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Sample records for selenization atmosphere revealed

  1. Studies of rubidium selenate with secondary phase of RbOH under humidified reducing atmosphere

    International Nuclear Information System (INIS)

    Beyribey, Berceste; Hallinder, Jonathan; Poulsen, Finn Willy; Bonanos, Nikolaos; Mogensen, Mogens

    2012-01-01

    Highlights: ► Degradation of Rb 2 SeO 3 and Rb 2 SeO 4 to form RbOH provide protonic conductivity. ► The conductivity increases by increasing temperature. ► The highest conductivity value of 2.01·10 −4 S cm −1 is observed at 317 °C. ► The work may state conductivity rise in solid acid electrolytes upon decomposition. - Abstract: The high temperature properties of Rb 2 SeO 4 have been studied by calorimetry, impedance spectroscopy and X-ray powder diffraction. As synthesized, Rb 2 SeO 4 includes a second phase of Rb 2 SeO 3 , which can be eliminated upon heating the compound. As expected, no conductivity is observed in dry (pH 2 O 2 O = 0.1 bar) air at 176 °C, the conductivity increases sharply from 8.6·10 −8 to 1.7·10 −6 S cm −1 . Under humidified (pH 2 O = 0.1 bar) reducing atmosphere (9%H 2 in N 2 ), the conductivity increases to 2.0·10 −4 S cm −1 at 317 °C. Degradation of Rb 2 SeO 3 and Rb 2 SeO 4 to form RbOH, which is known as a proton conductor, are thought to be responsible for the observed conductivity in humidified atmospheres. Our observations may explain the conductivity rise in other solid acid electrolytes, including sulfate and selenate groups, around their decomposition temperatures, in humidified atmospheres.

  2. Studies of rubidium selenate with secondary phase of RbOH under humidified reducing atmosphere

    DEFF Research Database (Denmark)

    Beyribey, Berceste; Hallinder, Jonathan; Poulsen, Finn Willy

    2012-01-01

    The high temperature properties of Rb2SeO4 have been studied by calorimetry, impedance spectroscopy and X-ray powder diffraction. As synthesized, Rb2SeO4 includes a second phase of Rb2SeO3, which can be eliminated upon heating the compound. As expected, no conductivity is observed in dry (pH2O ....001 bar) air. By changing to humidified (pH2O = 0.1 bar) air at 176 deg. C, the conductivity increases sharply from 8.6·10-8 to 1.7·10-6 S cm-1. Under humidified (pH2O = 0.1 bar) reducing atmosphere (9%H2 in N2), the conductivity increases to 2.0·10-4 S cm-1 at 317 C. Degradation of Rb2SeO3 and Rb2SeO4...

  3. Sneaking of the Solar Wind Ions Into the Lunar Anti-subsolar Region Revealed by SELENE (Kaguya)

    Science.gov (United States)

    Nishino, M. N.; Fujimoto, M.; Saito, Y.; Shoichiro, Y.; Asamura, K.; Tanaka, T.; Tsunakawa, H.; Shibuya, H.; Matsushima, M.; Shimizu, H.; Takahashi, F.; Maezawa, K.; Terasawa, T.

    2008-12-01

    The moon spends more than 80 percent of its life staying in the solar wind (SW), where a quasi-vacuum region called the lunar wake is formed on the night side. The SW electrons with higher energy can come to the lunar night-side surface, while it has been thought that the SW ions are unlikely to approach the low altitude region on the night side because their thermal speed is much lower than the SW bulk speed. Here we show detection of SW ions sneaking into the anti-subsolar region at ~100 km altitude, using recent comprehensive measurement by a Japanese lunar orbiter SELENE (Kaguya). The sneaking of SW ions into the deepest lunar wake was accompanied by an enhancement of counter-streaming electrons along the SW magnetic field. A part of the ions detected in the anti-subsolar region came from the lunar surface, which means that the ions of solar wind origin reflected at the night-side surface. One possibility is that electron- rich wake environment strengthened the bipolar electric field at the wake boundary to let solar-wind ions approach the lunar night side, and the other scenario is that enhancement of ions in the wake let ambient electrons to come in. The sneaking mechanism of the solar wind ions in terms of plasma and electromagnetic environment around/inside the lunar wake will be discussed.

  4. Learning Lunar Science Through the Selene Videogame

    Science.gov (United States)

    Reese, D. D.; Wood, C. A.

    2010-03-01

    Selene is a videogame to promote and assess learning of lunar science concepts. As players build and modify a Moon, Selene measures learning as it occurs. Selene is a model for 21st century learning and embedded assessment.

  5. A Comprehensive Study of One-Step Selenization Process for Cu(In1-x Ga x )Se2 Thin Film Solar Cells.

    Science.gov (United States)

    Chen, Shih-Chen; Wang, Sheng-Wen; Kuo, Shou-Yi; Juang, Jenh-Yih; Lee, Po-Tsung; Luo, Chih Wei; Wu, Kaung-Hsiung; Kuo, Hao-Chung

    2017-12-01

    In this work, aiming at developing a rapid and environmental-friendly process for fabricating CuIn 1-x Ga x Se 2 (CIGS) solar cells, we demonstrated the one-step selenization process by using selenium vapor as the atmospheric gas instead of the commonly used H 2 Se gas. The photoluminescence (PL) characteristics indicate that there exists an optimal location with superior crystalline quality in the CIGS thin films obtained by one-step selenization. The energy dispersive spectroscopy (EDS) reveals that the Ga lateral distribution in the one-step selenized CIGS thin film is intimately correlated to the blue-shifted PL spectra. The surface morphologies examined by scanning electron microscope (SEM) further suggested that voids and binary phase commonly existing in CIGS films could be successfully eliminated by the present one-step selenization process. The agglomeration phenomenon attributable to the formation of MoSe 2 layer was also observed. Due to the significant microstructural improvement, the current-voltage (J-V) characteristics and external quantum efficiency (EQE) of the devices made of the present CIGS films have exhibited the remarkable carrier transportation characteristics and photon utilization at the optimal location, resulting in a high conversion efficiency of 11.28%. Correlations between the defect states and device performance of the one-step selenized CIGS thin film were convincingly delineated by femtosecond pump-probe spectroscopy.

  6. Double selenates of rare earths and ammonium

    International Nuclear Information System (INIS)

    Iskhakova, L.D.; Kozlova, N.P.; Makarevich, L.G.

    1991-01-01

    Double selenates of rare earths with ammonium were prepared in result of crystallization. It is shown that NH 4 Ln(SeO 4 ) · nH 2 O crystalline hydrates are presented by penta-and trihydrates. Existance of two modifications was revealed for NH 4 Ln(SeO 4 ) · 5H 2 O: monoclinic form of NH 4 La(SeO 4 ) 2 · 5H 2 O, isostructural RbCe(SeO 4 ) 2 · 5H 2 O, and earlier unknown rhombic form of salts with Ln = Pr, Nd. Trihydrates with Ln = Sm-Yb belong to structural type of RbNd(SeO 4 ) 2 · 3H 2 O. Anhydrous salts NH 4 Ln(SeO 4 ) 2 are isostructural with monoclinic KNd(SO 4 ) 2 modification. Lattice parameters of binary selenates are presented

  7. Characteristics of CuInSe sub 2 thin films grown by the selenization method

    CERN Document Server

    Kim, S D; Adurodija, F O; Yoon, K H; Song, J S

    1999-01-01

    CuInSe sub 2 thin films were formed from a selenization of co-sputtered Cu-In alloy layers which consisted of only two phases, CuIn sub 2 and Cu sub 1 sub 1 In sub 9. A linear dependence of the Cu-In alloy film composition on the Cu/In sputtering power was found. The metallic layers were selenized in vacuum or at 1 atm. A small number of Cu-Se and In-Se compounds was observed during the early stage of selenization, and single-phase CuInSe sub 2 was more easily formed in vacuum than at atmospheric pressure. Therefore, CuInSe sub 2 films selenized in vacuum showed larger grain sizes, smoother surfaces, and denser microstructures than those selenized at 1 atm.

  8. Characteristics of CuInSe2 thin films grown by the selenization method

    International Nuclear Information System (INIS)

    Kim, Sang Deok; Kim, Hyeong Joon; Adurodija, Frederick Ojo; Yoon, Kyeong Hoon; Song, Jin Soo

    1999-01-01

    CuInSe 2 thin films were formed from a selenization of co-sputtered Cu-In alloy layers which consisted of only two phases, CuIn 2 and Cu 11 In 9 . A linear dependence of the Cu-In alloy film composition on the Cu/In sputtering power was found. The metallic layers were selenized in vacuum or at 1 atm. A small number of Cu-Se and In-Se compounds was observed during the early stage of selenization, and single-phase CuInSe 2 was more easily formed in vacuum than at atmospheric pressure. Therefore, CuInSe 2 films selenized in vacuum showed larger grain sizes, smoother surfaces, and denser microstructures than those selenized at 1 atm

  9. SELENE

    Indian Academy of Sciences (India)

    Institute of Space and Astronautical Science, Japan Aerospace Exploration ... launch target is rescheduled for 2006 due to delay of completion of launch vehicle, H-IIA. ... Mapping of subsurface structure using active sounding, frequency 5MHz,.

  10. Selene: A Videogame for Learning about the Moon

    Science.gov (United States)

    Wood, C. A.; Reese, D. D.

    2008-06-01

    The Selene game-based, metaphor-enhanced (GaME) learning object prepares players with concrete knowledge of basic lunar geology processes. Selene is embedded within an online research environment studying learning and assessment within videogames.

  11. Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements

    Science.gov (United States)

    Gatti, L. V.; Gloor, M.; Miller, J. B.; Doughty, C. E.; Malhi, Y.; Domingues, L. G.; Basso, L. S.; Martinewski, A.; Correia, C. S. C.; Borges, V. F.; Freitas, S.; Braz, R.; Anderson, L. O.; Rocha, H.; Grace, J.; Phillips, O. L.; Lloyd, J.

    2014-02-01

    Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48+/-0.18 petagrams of carbon per year (PgCyr-1) during the dry year but was carbon neutral (0.06+/-0.1PgCyr-1) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25+/-0.14PgCyr-1, which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39+/-0.10PgCyr-1 previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.

  12. Selen og vitamin E til svin

    DEFF Research Database (Denmark)

    Nielsen, H. E.; Danielsen, V.; Nielsen, Gunnar Gissel

    1975-01-01

    , kan der let opstå selenmangel. Vitamin E kan i nogen grad erstatte selen, men kun indenfor visse grænser. De senere års erfaringer har tydeligt vist, at der ofte opstår selenmangel, selvom der findes rigeligt E-vitamin i foderet. Resultaterne fra dette forsøg tyder på, at en nedsættelse af...

  13. Selenization of CIS and CIGS layers deposited by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Babu, B. J.; Egaas, B.; Velumani, S.

    2018-03-21

    Cu(In1-xGax)Se2 (CIGS) thin films with x=0 (CIS) and x=0.3 (CIGS) were prepared on Mo-coated glass substrate by using chemical spray pyrolysis at a substrate temperature of 350 degrees C, followed by selenization treatment at 550 degrees C in selenium environment under N2 gas flow. X-ray diffraction patterns of as-deposited CIGS layers on Mo showed polycrystalline chalcopyrite phase with an intense (112) plane. Splitting of (204)/(220) and (116)/(312) planes for the film with x=0.3 reveals deviation of tetragonal nature. Field emission scanning electron microscopy cross-sectional images of selenized films showed clear re-crystallization of grains. During the selenization process of the CIGS absorber, a thin interface layer of MoSe2 is formed. Line mapping of Mo/CIGS layer showed more gallium segregation at the interface of back contact resulting in band gap grading. Chemical composition and mapping of the as-deposited and selenized samples were determined by energy dispersive analysis of X-rays. This work leads to fabrication of low cost and large scale Mo/CIGS/CdS/ZnO/ZnO:Al device structure.

  14. Upper atmospheric gravity wave details revealed in nightglow satellite imagery

    Science.gov (United States)

    Miller, Steven D.; Straka, William C.; Yue, Jia; Smith, Steven M.; Alexander, M. Joan; Hoffmann, Lars; Setvák, Martin; Partain, Philip T.

    2015-01-01

    Gravity waves (disturbances to the density structure of the atmosphere whose restoring forces are gravity and buoyancy) comprise the principal form of energy exchange between the lower and upper atmosphere. Wave breaking drives the mean upper atmospheric circulation, determining boundary conditions to stratospheric processes, which in turn influence tropospheric weather and climate patterns on various spatial and temporal scales. Despite their recognized importance, very little is known about upper-level gravity wave characteristics. The knowledge gap is mainly due to lack of global, high-resolution observations from currently available satellite observing systems. Consequently, representations of wave-related processes in global models are crude, highly parameterized, and poorly constrained, limiting the description of various processes influenced by them. Here we highlight, through a series of examples, the unanticipated ability of the Day/Night Band (DNB) on the NOAA/NASA Suomi National Polar-orbiting Partnership environmental satellite to resolve gravity structures near the mesopause via nightglow emissions at unprecedented subkilometric detail. On moonless nights, the Day/Night Band observations provide all-weather viewing of waves as they modulate the nightglow layer located near the mesopause (∼90 km above mean sea level). These waves are launched by a variety of physical mechanisms, ranging from orography to convection, intensifying fronts, and even seismic and volcanic events. Cross-referencing the Day/Night Band imagery with conventional thermal infrared imagery also available helps to discern nightglow structures and in some cases to attribute their sources. The capability stands to advance our basic understanding of a critical yet poorly constrained driver of the atmospheric circulation. PMID:26630004

  15. Structure, vibrations and quantum chemical investigations of hydrogen bonded complex of bis(1-hydroxy-2-methylpropan-2-aminium)selenate

    Science.gov (United States)

    Thirunarayanan, S.; Arjunan, V.; Marchewka, M. K.; Mohan, S.

    2017-04-01

    The hydrogen bonded molecular complex bis(1-hydroxy-2-methylpropan-2-aminium)selenate (C8H24N2O6Se) has been prepared by the reaction of 2-amino-2-methyl propanol and selenic acid. The X-ray diffraction analysis revealed that the intermolecular proton transfer from selenic acid (SeO4H2) to 2-amino-2-methylpropanol results in the formation of bis(1-hydroxy-2-methylpropan-2-aminium)selenate (HMPAS) salt and the fragments are connected through H-bonding and ion pairing. The N-H⋯O and O-H⋯O interactions between 2-amino-2-methylpropanol and selenic acid determine the supramolecular arrangement in three-dimensional space. The salt crystallises in the space group P121/n1 of monoclinic system. The complete vibrational assignments of HMPAS have been performed by FTIR and FT-Raman spectroscopy. The experimental data are correlated with the structural properties namely the energy, thermodynamic parameters, atomic charges, hybridization concepts and vibrational frequencies determined by quantum chemical studies performed with B3LYP method using 6-311++G*, 6-31+G* and 6-31G** basis sets.

  16. SELENE - Self-Forming Extensible Lunar EVA Network, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of this research effort (Phase I and Phase II) by Scientific Systems Company, Inc. and BBN Technologies is to develop the SELENE network --...

  17. Optimization of selenizing conditions for Seleno-Lentinan and its characteristics.

    Science.gov (United States)

    Ren, Guangming; Li, Koukou; Hu, Yang; Yu, Min; Qu, Juanjuan; Xu, Xiuhong

    2015-11-01

    Lentinan was successfully modified with nitric acid-sodium selenite method based on L9(3(4)) orthogonal experiments. The optimum selenizing conditions were obtained according to selenium conversion rate as follows: Lentinan of 1.0g, pH of 4.5, temperature of 70°C and sodium selenite of 1.50g. The antioxidant activity assays in vitro (DPPH, reducing power, superoxide radicals and hydroxyl radicals) proved that Lentinan had stronger antioxidant activity after selenizing. The elevations of serum alanine aminotransferase and aspartate aminotransferase, as well as the abnormal hepatic architecture, verified that oral administration of Seleno-Lentinan (SL2-1) markedly alleviated oxidative damage in the liver of mice induced by D-gal. In addition, SL2-1 significantly increased total antioxidant capacity, activities and protein expressions of catalase and glutathione peroxidase and lowered malondialdehyde levels in serum and liver. Fourier transform infrared spectroscopy analysis indicated that selenium of SL2-1 was mostly existed as the formations of OSeO, SeO and SeOC. Scanning electron microscope coupled with energy dispersive X-ray spectroscopy analysis revealed that the surface structure and elemental components of Lentinan significantly changed after selenizing. The results are instructive for the development of organic selenium-supplement resource. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The intensity of tyrosine nitration is associated with selenite and selenate toxicity in Brassica juncea L.

    Science.gov (United States)

    Molnár, Árpád; Feigl, Gábor; Trifán, Vanda; Ördög, Attila; Szőllősi, Réka; Erdei, László; Kolbert, Zsuzsanna

    2018-01-01

    Selenium phytotoxicity involves processes like reactive nitrogen species overproduction and nitrosative protein modifications. This study evaluates the toxicity of two selenium forms (selenite and selenate at 0µM, 20µM, 50µM and 100µM concentrations) and its correlation with protein tyrosine nitration in the organs of hydroponically grown Indian mustard (Brassica juncea L.). Selenate treatment resulted in large selenium accumulation in both Brassica organs, while selenite showed slight root-to-shoot translocation resulting in a much lower selenium accumulation in the shoot. Shoot and root growth inhibition and cell viability loss revealed that Brassica tolerates selenate better than selenite. Results also show that relative high amounts of selenium are able to accumulate in Brassica leaves without obvious visible symptoms such as chlorosis or necrosis. The more severe phytotoxicity of selenite was accompanied by more intense protein tyrosine nitration as well as alterations in nitration pattern suggesting a correlation between the degree of Se forms-induced toxicities and nitroproteome size, composition in Brassica organs. These results imply the possibility of considering protein tyrosine nitration as novel biomarker of selenium phytotoxicity, which could help the evaluation of asymptomatic selenium stress of plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Rate of oxygen isotope exchange between selenate and water.

    Science.gov (United States)

    Kaneko, Masanori; Poulson, Simon R

    2012-04-17

    The rate of oxygen isotope exchange between selenate and water was investigated at conditions of 10 to 80 °C and pH -0.6 to 4.4. Oxygen isotope exchange proceeds as a first-order reaction, and the exchange rate is strongly affected by reaction temperature and pH, with increased rates of isotope exchange at higher temperature and lower pH. Selenate speciation (HSeO(4)(-) vs SeO(4)(2-)) also has a significant effect on the rate of isotope exchange. The half-life for isotope exchange at example natural conditions (25 °C and pH 7) is estimated to be significantly in excess of 10(6) years. The very slow rate of oxygen isotope exchange between selenate and water under most environmental conditions demonstrates that selenate-δ(18)O signatures produced by biogeochemical processes will be preserved and hence that it will be possible to use the value of selenate-δ(18)O to investigate the biogeochemical behavior of selenate, in an analogous fashion to the use of sulfate-δ(18)O to study the biogeochemical behavior of sulfate.

  20. Determination of Proteinaceous Selenocysteine in Selenized Yeast

    Directory of Open Access Journals (Sweden)

    Katarzyna Bierla

    2018-02-01

    Full Text Available A method for the quantitation of proteinaceous selenocysteine (SeCys in Se-rich yeast was developed. The method is based on the reduction of the Se-Se and S-Se bridges with dithiotretiol, derivatization with iodoacetamide (carbamidomethylation, followed by HPLC-ICP MS. The chromatographic conditions were optimized for the total recovery of the proteinaceous selenocysteine, the minimum number of peaks in the chromatogram (reduction of derivatization products of other Se-species present and the baseline separation. A typical chromatogram of a proteolytic digest of selenized yeast protein consisted of up to five peaks (including SeMet, carbamidomethylated (CAM-SeCys, and Se(CAM2 identified by retention time matching with available standards and electrospray MS. Inorganic selenium non-specifically attached to proteins and selenomethionine could be quantified (in the form of Se(CAM2 along with SeCys. Selenocysteine, selenomethionine, inorganic selenium, and the water soluble-metabolite fraction accounted for the totality of selenium species in Se-rich yeast.

  1. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    Science.gov (United States)

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  2. Preparation, characterization and thermal behaviour study of double selenates of lanthanides, yttrium and beryllium

    International Nuclear Information System (INIS)

    Ribeiro, C.A.

    1988-01-01

    The lanthanides (III) and yttrium (III) double selenates were studied using common analytical methods, atomic absorption, X-ray diffraction infra-red absorption, thermogravimetry and differential thermal analysis. These compounds were prepared from the mixture of lanthanides (III) and yttrium (III) selenates aqueous solution and basic beryllium selenates aqueous solution, obeying equimolar relation (1:1) to the cation

  3. Cation–Anion Interactions within the Nucleic Acid Ion Atmosphere Revealed by Ion Counting

    Science.gov (United States)

    Gebala, Magdalena; Giambasu, George M.; Lipfert, Jan; Bisaria, Namita; Bonilla, Steve; Li, Guangchao; York, Darrin M.; Herschlag, Daniel

    2016-01-01

    The ion atmosphere is a critical structural, dynamic, and energetic component of nucleic acids that profoundly affects their interactions with proteins and ligands. Experimental methods that “count” the number of ions thermodynamically associated with the ion atmosphere allow dissection of energetic properties of the ion atmosphere, and thus provide direct comparison to theoretical results. Previous experiments have focused primarily on the cations that are attracted to nucleic acid polyanions, but have also showed that anions are excluded from the ion atmosphere. Herein, we have systematically explored the properties of anion exclusion, testing the zeroth-order model that anions of different identity are equally excluded due to electrostatic repulsion. Using a series of monovalent salts, we find, surprisingly, that the extent of anion exclusion and cation inclusion significantly depends on salt identity. The differences are prominent at higher concentrations and mirror trends in mean activity coefficients of the electrolyte solutions. Salts with lower activity coefficients exhibit greater accumulation of both cations and anions within the ion atmosphere, strongly suggesting that cation–anion correlation effects are present in the ion atmosphere and need to be accounted for to understand electrostatic interactions of nucleic acids. To test whether the effects of cation–anion correlations extend to nucleic acid kinetics and thermodynamics, we followed the folding of P4–P6, a domain of the Tetrahymena group I ribozyme, via single-molecule fluorescence resonance energy transfer in solutions with different salts. Solutions of identical concentration but lower activity gave slower and less favorable folding. Our results reveal hitherto unknown properties of the ion atmosphere and suggest possible roles of oriented ion pairs or anion-bridged cations in the ion atmosphere for electrolyte solutions of salts with reduced activity. Consideration of these new

  4. Growth of Cu(In,Al)(Se,S)2 thin films by selenization and sulfurization for a wide bandgap absorber

    International Nuclear Information System (INIS)

    Fujiwara, C.; Kawasaki, Y.; Sato, T.; Sugiyama, M.; Chichibu, S.F.

    2010-01-01

    Full text : Chalcopyrite structure Cu(In 1 .xAlx)(S y Se 1 -y) 2 (CIASS) alloys are attracting attention as promising candidates for the light-absorbing medium of high conversion efficiency, low cost, and lightweight solar cells. In addition, according to the wide variation in the bandgap energy (1.0-3.5eV), multiple-junction or tandem solar cells able to be fabricated using CIASS films of different compositions, x and y. In fact, several research groups have recently fabricated Cu(In,Al)Se 2 -based solar cells, and a high μ of 16.9 percent has been demonstrated. The sulfurization following selenization of Cu(In,Ga)Se2 (CIGS) films is believed to be promising for bandgap engineering of absorber material. Furthermore, it has been reported that the controlled incorporation of sulfur into CIGS films reduces the carrier recombination in the space charge region due to the deep trap states. Therefore, the sulfurization following selenization is expected to be used as a method of growth of CIASS films. However, sulfurization condition following selenization for obtaining CIASS films has not been clarified. The crystal growth of CIASS must be studied for solar cell applications. In this study, the advantages of using sulfurization for the growth of CIASS will be presented. Cu-In-Al precursors were selenized using diethylselenide (DESe) at 515-570 degrees Celsium for 60- 90 min under atmospheric pressure. The flow rates of DESe and N 2 carrier gases were 35 imol/min and 2 L/min, respectively. The films were then sulfurized at 550 degrees Celsium using S vapor. These films were characterized by SEM, EDX, XRD, and PL measurements. Using the selenization and sulfurization technique, polycrystalline Cu(In,Al)Se 2 , CuIn(Se,S) 2 , CuInS 2 films with thickness of approximately 2.0 im were formed without additional annealing. The films adhered well to the Mo/SLG substrate, which was confirmed by the peeling test. Phase separations, i.e. distinct peaks corresponding to CuInSe 2

  5. Initial investigations of microscale cellular convection in an equatorial marine atmospheric boundary layer revealed by lidar

    Science.gov (United States)

    Cooper, D. I.; Eichinger, W. E.; Ecke, R. E.; Kao, J. C. Y.; Reisner, J. M.; Tellier, L. L.

    During the Combined Sensor Program (CSP) in March of 1996, the Los Alamos National Laboratory (LANL) fielded an advanced scanning Raman lidar. The lidar was part of a larger suite of micrometeorological sensors to quantify processes associated with the ocean-atmosphere interface, including intermittency and coherent atmospheric features in the “warm pool” of the Tropical Western Pacific (TWP) near Manus Island (2° S. lat, 147° E. long). Initial inspection of the data has revealed excellent information on the microscale vertical and horizontal spatial and temporal structure of the equatorial Marine Atmospheric Boundary Layer (MABL). The data from this experiment have added to the increasing body of measurements on surface layer convection and intermittency including, for the first time, the observation of microscale cellular convective structures such as hexagonal patterns associated with Rayleigh-Bénard cells.

  6. Respiration of arsenate and selenate by hyperthermophilic archaea.

    Science.gov (United States)

    Huber, R; Sacher, M; Vollmann, A; Huber, H; Rose, D

    2000-10-01

    A novel, strictly anaerobic, hyperthermophilic, facultative organotrophic archaeon was isolated from a hot spring at Pisciarelli Solfatara, Naples, Italy. The rod-shaped cells grew chemolithoautotrophically with carbon dioxide as carbon source, hydrogen as electron donor and arsenate, thiosulfate or elemental sulfur as electron acceptor. H2S was formed from sulfur or thiosulfate, arsenite from arsenate. Organotrophically, the new isolate grew optimally in the presence of an inorganic electron acceptor like sulfur, selenate or arsenate. Cultures, grown on arsenate and thiosulfate or arsenate and L-cysteine, precipitated realgar (As2S2). During growth on selenate, elemental selenium was produced. The G+C content of the DNA was 58.3 mol%. Due to 16S rRNA gene sequence analysis combined with physiological and morphological criteria, the new isolate belongs to the Thermoproteales order. It represents a new species within the genus Pyrobaculum, the type species of which we name Pyrobaculum arsenaticum (type strain PZ6*, DSM 13514, ATCC 700994). Comparative studies with different Pyrobaculum-species showed, that Pyrobaculum aerophilum was also able to grow organotrophically under anaerobic culture conditions in the presence of arsenate, selenate and selenite. During growth on selenite, elemental selenium was formed as final product. In contrast to P. arsenaticum, P. aerophilum could use selenate or arsenate for lithoautotrophic growth with carbon dioxide and hydrogen.

  7. Orbit Determination of the SELENE Satellites Using Multi-Satellite Data Types and Evaluation of SELENE Gravity Field Models

    Science.gov (United States)

    Goossens, S.; Matsumoto, K.; Noda, H.; Araki, H.; Rowlands, D. D.; Lemoine, F. G.

    2011-01-01

    The SELENE mission, consisting of three separate satellites that use different terrestrial-based tracking systems, presents a unique opportunity to evaluate the contribution of these tracking systems to orbit determination precision. The tracking data consist of four-way Doppler between the main orbiter and one of the two sub-satellites while the former is over the far side, and of same-beam differential VLBI tracking between the two sub-satellites. Laser altimeter data are also used for orbit determination. The contribution to orbit precision of these different data types is investigated through orbit overlap analysis. It is shown that using four-way and VLBI data improves orbit consistency for all satellites involved by reducing peak values in orbit overlap differences that exist when only standard two-way Doppler and range data are used. Including laser altimeter data improves the orbit precision of the SELENE main satellite further, resulting in very smooth total orbit errors at an average level of 18m. The multi-satellite data have also resulted in improved lunar gravity field models, which are assessed through orbit overlap analysis using Lunar Prospector tracking data. Improvements over a pre-SELENE model are shown to be mostly in the along-track and cross-track directions. Orbit overlap differences are at a level between 13 and 21 m with the SELENE models, depending on whether l-day data overlaps or I-day predictions are used.

  8. Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

    Energy Technology Data Exchange (ETDEWEB)

    Bao, L.M., E-mail: baoliangman@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, G.L., E-mail: zhangguilin@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Lei, Q.T.; Li, Y.; Li, X.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Hwu, Y.K. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Yi, J.M. [Advanced Photon Source, Argonne National Laboratory, Argonne 60439 (United States)

    2015-09-15

    For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

  9. Entwicklung und Anwendung von Methoden zur Bestimmung von Selen-Spezies in human-biologischem Material

    OpenAIRE

    Jäger, Thomas

    2014-01-01

    Selen ist essentieller Bestandteil von mehr als 25 physiologisch wichtigen menschlichen Enzymen. Der tägliche Bedarf wird überwiegend in Form von organischen Selenverbindungen wie Selenmethionin oder Selenocystein aus der Nahrung aufgenommen. Weitere Expositionswege sind die Einnahme von Nahrungsergänzungsmitteln zur Selensupplementation sowie die inhalative oder dermale Aufnahme von in erster Linie anorganischen Selenverbindungen oder elementarem Selen an Arbeitsplätzen der Selen-verarbeiten...

  10. The chemical consequences of thermal neutron capture in alkali selenates

    International Nuclear Information System (INIS)

    Duplatre, G.; Vargas, J.I.

    1977-01-01

    The initial retention of the SeO 4 2- ion after thermal neutron capture has been studied in various matrices by chemical analysis. A comparison between the thermal behaviour of the chemically analyzed Sesup(IV) and the disappearance of the E.P.R. species SeO 3 - and SeO 4 3- showed that the retention fraction would include all species with oxidation state higher or equal to VI. The retentions observed in the different matrices show the existence of four families with respective retentions of: 2.6%[K 2 SeO 4 diluted in (NH 4 ) 2 SO 4 ], 9.2% [anhydrous and hydrated Li and Ca selenates; K 2 SeO 4 diluted in NaIO 3 ; Se + implanted in K 2 SeO 4 ; Triglycine selenate], 21.5% [K 2 SeO 4 diluted in KNO 3 , K 2 SO 4 , Na 2 WO 4 and Na 2 WO 4 .2H 2 O] and 32.0% [Na,K and Cs selenates]. Whereas chemical considerations may be invoked for the (NH 4 ) 2 SO 4 matrix, a mechanical model is proposed for the three other groups. (author)

  11. Variation in electrical properties of gamma irradiated cadmium selenate nanowires

    Science.gov (United States)

    Chauhan, R. P.; Rana, Pallavi; Narula, Chetna; Panchal, Suresh; Choudhary, Ritika

    2016-07-01

    Preparation of low-dimensional materials attracts more and more interest in the last few years, mainly due to the wide field of potential commercial applications ranging from life sciences, medicine and biotechnology to communication and electronics. One-dimensional systems are the smallest dimension structures that can be used for efficient transport of electrons and thus expected to be critical to the function and integration of nanoscale devices. Nanowires with well controlled morphology and extremely high aspect ratio can be obtained by replicating a nanoporous polymer ion-track membrane with cylindrical pores of controlled dimensions. With this technique, materials can be deposited within the pores of the membrane by electrochemical reduction of the desired ion. In the present study, cadmium selenate nanowires were synthesized potentiostatically via template method. These synthesized nanowires were then exposed to gamma rays by using a 60Co source at the Inter University Accelerator Centre, New Delhi, India. Structural, morphological, electrical and elemental characterizations were made in order to analyze the effect of gamma irradiation on the synthesized nanowires. I-V measurements of cadmium selenate nanowires, before and after irradiation were made with the help of Keithley 2400 source meter and Ecopia probe station. A significant change in the electrical conductivity of cadmium selenate nanowires was found after gamma irradiation. The crystallography of the synthesized nanowires was also studied using a Rigaku X-ray diffractrometer equipped with Cu-Kα radiation. XRD patterns of irradiated samples showed no variation in the peak positions or phase change.

  12. Variation in electrical properties of gamma irradiated cadmium selenate nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, R.P., E-mail: chauhanrpc@gmail.com; Rana, Pallavi, E-mail: prana.phy@gmail.com; Narula, Chetna; Panchal, Suresh; Choudhary, Ritika

    2016-07-15

    Preparation of low-dimensional materials attracts more and more interest in the last few years, mainly due to the wide field of potential commercial applications ranging from life sciences, medicine and biotechnology to communication and electronics. One-dimensional systems are the smallest dimension structures that can be used for efficient transport of electrons and thus expected to be critical to the function and integration of nanoscale devices. Nanowires with well controlled morphology and extremely high aspect ratio can be obtained by replicating a nanoporous polymer ion-track membrane with cylindrical pores of controlled dimensions. With this technique, materials can be deposited within the pores of the membrane by electrochemical reduction of the desired ion. In the present study, cadmium selenate nanowires were synthesized potentiostatically via template method. These synthesized nanowires were then exposed to gamma rays by using a {sup 60}Co source at the Inter University Accelerator Centre, New Delhi, India. Structural, morphological, electrical and elemental characterizations were made in order to analyze the effect of gamma irradiation on the synthesized nanowires. I–V measurements of cadmium selenate nanowires, before and after irradiation were made with the help of Keithley 2400 source meter and Ecopia probe station. A significant change in the electrical conductivity of cadmium selenate nanowires was found after gamma irradiation. The crystallography of the synthesized nanowires was also studied using a Rigaku X-ray diffractrometer equipped with Cu-Kα radiation. XRD patterns of irradiated samples showed no variation in the peak positions or phase change.

  13. Regional Atmospheric CO2 Inversion Reveals Seasonal and Geographic Differences in Amazon Net Biome Exchange

    Science.gov (United States)

    Alden, Caroline B.; Miller, John B.; Gatti, Luciana V.; Gloor, Manuel M.; Guan, Kaiyu; Michalak, Anna M.; van der Laan-Luijkx, Ingrid; Touma, Danielle; Andrews, Arlyn; Basso, Luana G.; hide

    2016-01-01

    Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (Approx.1-8 x 10(exp -6) km2) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub

  14. Inhibition of synthesis of heparan sulfate by selenate: Possible dependence on sulfation for chain polymerization

    International Nuclear Information System (INIS)

    Dietrich, C.P.; Nader, H.B.; Buonassisi, V.; Colburn, P.

    1988-01-01

    Selenate, a sulfation inhibitor, blocks the synthesis of heparan sulfate and chondroitin sulfate by cultured endothelial cells. In contrast, selenate does not affect the production of hyaluronic acid, a nonsulfated glycosaminoglycan. No differences in molecular weight, [ 3 H]glucosamine/[ 35 S]sulfuric acid ratios, or disaccharide composition were observed when the heparan sulfate synthesized by selenate-treated cells was compared with that of control cells. The absence of undersulfated chains in preparations from cultures exposed to selenate supports the concept that, in the intact cell, the polymerization of heparan sulfate might be dependent on the sulfation of the saccharide units added to the growing glycosaminoglycan chain

  15. Scaling Equation of State for Ferroelectric Triglycine Selenate at T ≈ Tc

    NARCIS (Netherlands)

    Iglesias, T.; Noheda, B.; Gallego, B.; Fernández del Castillo, J.R.; Lifante, G.; Gonzalo, J.A.

    1994-01-01

    Digital data of polarization vs. field on triglycine selenate at closely spaced temperature intervals (ΔT ≈ 0.015) in the vicinity of the quasi-tricritical point of triglycine selenate have been collected. These data fulfill very well the scaling equation of state ê± = ±p + (1/5)p5 (where ê- and ê+

  16. Thermal decomposition of double selenates of lanthanides (III), yttrium (III) and ammonium

    International Nuclear Information System (INIS)

    Crespi, M.S.

    1989-01-01

    Double selenates of lanthanides, yttrium and ammonium were prepared by treating mixtures of simple selenates with equimolar amounts and then dried in a vacuum desiccator containing anhydrous calcium chloride, protected from light. The compounds were studied using the conventional analytical methods such as infrared absorption spectra, X-ray diffraction, differential thermal analysis (DTA), and thermogravimetry (TG). (author)

  17. Modeling selenate adsorption behavior on oxides, clay minerals, and soils using the triple layer model

    Science.gov (United States)

    Selenate adsorption behavior was investigated on amorphous aluminum oxide, amorphous iron oxide, goethite, clay minerals: kaolinites, montmorillonites, illite, and 18 soil samples from Hawaii, and the Southwestern and the Midwestern regions of the US as a function of solution pH. Selenate adsorpti...

  18. Uptake and Distribution of Added Selenite and Selenate by Barley and Red Clover as Influenced by Sulphur

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel

    1973-01-01

    The uptake of added Se from selenite and selenate by barley and red clover was investigated in a pot experiment. Much more of selenate than of selenite was taken up but the Se concentrations in the plants declined more with time when selenate was the source. Increasing sulphate addition to the soil...

  19. The influence of temperature on selenate adsorption by goethite

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, M.; Vlasova, N. [Mainz Univ. (Germany). Geosciences Inst.

    2013-08-01

    Acid-base batch titration data up to 75 C were used to constrain a temperature-dependent 1-pK basic Stern model of the surface protonation reactions of goethite. Experimental data for the temperature dependence of pH{sub PZC} (as determined using the two-term Van't Hoff extrapolation) yielded a negative value of -44.9 kJ/mol for the surface protonation enthalpy, and therefore a shift of the zero point of charge towards lower pH values with increasing temperature. Batch titrations at selenate concentrations of between 10 and 100 {mu}M showed an increased degree of adsorption in the acidic pH range, which appeared to be sensitive to the ionic strength of the solution. The selenate adsorption edges shifted towards more acidic pH values with increasing temperature. A 1-pK charge distribution multi-site surface complexation (CD-MUSIC) model was applied, assuming the formation of an outer-spheric surface complex together with an inner-spheric one, in agreement with published spectroscopic information. The temperature behaviour of the intrinsic equilibrium constants were well represented by a linear Van't Hoff log K vs. 1/T plot, from which negative enthalpy values could be derived for both adsorption reactions. The adsorption of the selenate was therefore exothermic and became weaker with increasing temperature. The bidentate inner-spheric complex was more sensitive to rises in temperature (-70 kJ/mol), compared to the outer-spheric complex (-36 kJ/mol). The latter ultimately became the dominating adsorption process at the highest temperature studied. (orig.)

  20. The influence of temperature on selenate adsorption by goethite

    International Nuclear Information System (INIS)

    Kersten, M.; Vlasova, N.

    2013-01-01

    Acid-base batch titration data up to 75 C were used to constrain a temperature-dependent 1-pK basic Stern model of the surface protonation reactions of goethite. Experimental data for the temperature dependence of pH PZC (as determined using the two-term Van't Hoff extrapolation) yielded a negative value of -44.9 kJ/mol for the surface protonation enthalpy, and therefore a shift of the zero point of charge towards lower pH values with increasing temperature. Batch titrations at selenate concentrations of between 10 and 100 μM showed an increased degree of adsorption in the acidic pH range, which appeared to be sensitive to the ionic strength of the solution. The selenate adsorption edges shifted towards more acidic pH values with increasing temperature. A 1-pK charge distribution multi-site surface complexation (CD-MUSIC) model was applied, assuming the formation of an outer-spheric surface complex together with an inner-spheric one, in agreement with published spectroscopic information. The temperature behaviour of the intrinsic equilibrium constants were well represented by a linear Van't Hoff log K vs. 1/T plot, from which negative enthalpy values could be derived for both adsorption reactions. The adsorption of the selenate was therefore exothermic and became weaker with increasing temperature. The bidentate inner-spheric complex was more sensitive to rises in temperature (-70 kJ/mol), compared to the outer-spheric complex (-36 kJ/mol). The latter ultimately became the dominating adsorption process at the highest temperature studied. (orig.)

  1. Preparation of SnSe thin films by encapsulated selenization

    International Nuclear Information System (INIS)

    Sabar D. Hutagalung; Samsudi Sakrani; Yussof Wahab

    1994-01-01

    Tin selenide thin films were prepared by encapsulated selenization. A stacked layer of evaporated Sn and Se films were annealed in a carbon block at temperatures 100 - 500 degree Celsius for 3 hours. X-ray analysis and SEM (Scanning electron) micrograph results showed that SnSe was initially formed at 150 degree Celsius with crystal size 30.0 nm and reached optimum formation at 200 daximum of 57.4 % yield of 5-decene. Other factors such as reaction temperatures, types of solvent and wt% of rhenium loadings influence the activity of the catalytic system

  2. Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite-selenates

    Science.gov (United States)

    Gurzhiy, Vladislav V.; Kovrugin, Vadim M.; Tyumentseva, Olga S.; Mikhaylenko, Pavel A.; Krivovichev, Sergey V.; Tananaev, Ivan G.

    2015-09-01

    Single crystals of seven novel uranyl oxysalts of selenium with protonated methylamine molecules, [C2H8N]2[(UO2)(SeO4)2(H2O)] (I), [C2H8N]2[(UO2)2(SeO4)3(H2O)] (II), [C4H15N3][H3O]0.5[(UO2)2(SeO4)2.93(SeO3)0.07(H2O)](NO3)0.5 (III), [C2H8N]3[H5O2][(UO2)2(SeO4)3(H2O)2]2(H2O)5 (IV), [C2H8N]2[H3O][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)0.2 (V), [C4H12N]3[H3O][(UO2)3(SeO4)5(H2O)] (VI), and [C2H8N]3(C2H7N)[(UO2)3(SeO4)4(HSeO3)(H2O)] (VII) have been prepared by isothermal evaporation from aqueous solutions. Their crystal structures have been solved by direct methods and their uranyl selenate and selenite-selenate units investigated using black-and-white graphs from the viewpoints of topology of interpolyhedral linkages and isomeric variations. The crystal structure of IV is based upon complex layers with unique topology, which has not been observed previously in uranyl selenates. Investigations of the statistics and local distribution of the U-Obr-Se bond angles demonstrates that shorter angles associate with undulations, whereas larger angles correspond to planar areas of the uranyl selenite layers.

  3. Selenate as a novel ligand for keplerate chemistry. New {W72Mo60} keplerates with selenates inside the cavity.

    Science.gov (United States)

    Korenev, Vladimir S; Abramov, Pavel A; Vicent, Cristian; Zhdanov, Artem A; Tsygankova, Alphiya R; Sokolov, Maxim N; Fedin, Vladimir P

    2015-05-21

    The synthesis and characterization of three novel keplerate-type compounds containing the {W72Mo60} mixed-metal core are reported. Complexes (NH4)72[{W6O21(H2O)6}12{Mo2O4(SeO4)}30]·150H2O·6(NH4)2SeO4 (1a) and (NH4)25(NH2Me2)47[{W6O21(H2O)6}12{Mo2O4(SeO4)}30]·130H2O·3(NH4)2SeO4 (1b) were prepared by ligand substitution from the acetate anionic complex [{W6O21(H2O)5(CH3COO)0.5}12{Mo2O4(CH3COO)}30](48-) and selenate. The selenate anions in keplerate ions [{W6O21(H2O)6}12{Mo2O4(SeO4)}30](72-) are very labile and easily aquate with the formation of [{W6O21(H2O)6}12{Mo2O4}30(SeO4)20(H2O)20](52-), which was isolated as (NH4)20(NH2Me2)32[{W6O21(H2O)6}12{Mo2O4}30(SeO4)20(H2O)20]·150H2O (2) and structurally characterized. In the crystal structure of 2 selenate has several coordination modes, preferentially bonding to the {Mo2O4}(2+) units, and, additionally, to the {(W)W5} pentagonal blocks. The compounds have been characterized by elemental analysis, Raman, IR and (77)Se NMR spectroscopy, and by ESI mass spectrometry. Capillary electrophoresis was used for characterization of keplerates in solution for the first time.

  4. Simultaneous selenate reduction and denitrification by a consortium of enriched mine site bacteria.

    Science.gov (United States)

    Subedi, Gaurav; Taylor, Jon; Hatam, Ido; Baldwin, Susan A

    2017-09-01

    Increasing selenium concentrations in aquatic environments downstream of mine sites is of great concern due to selenium's bioaccumulation propensity and teratogenic toxicity. Removal of selenium from mine influenced water is complicated by the presence of nitrate, which is also elevated in mine influenced water due to the use of explosives in mining. In many biological treatment processes, nitrate as a thermodynamically more preferable electron acceptor inhibits selenate reduction. Here we report on an enrichment of a bacterial assemblage from a mine impacted natural marsh sediment that was capable of simultaneous selenate reduction and denitrification. Selenate reduction followed first order kinetics with respect to the concentration of total dissolved selenium. The kinetic rate constant was independent of initial nitrate concentration over the range 3-143 mg L -1 -NO 3 - -N. The initial concentration of selenate inhibited selenate reduction kinetics over the range 1-24 mg-Se L -1 . Dominant taxa that grew in selenate only medium were classified in the genera Pseudomonas, Lysinibacillus and Thauera. When nitrate was introduced in addition to selenate, previously rare taxa that became dominant were relatives of Exiguobacterium, Tissierella and Clostridium. Open reading frames (ORFs) associated with dissimilatory denitrification were identified for Pseudomonas, Thauera and Clostridium. In addition, ORFs were found that were homologous with known selenate reductase subunits (SerA and SerB). These findings suggest that native mine site bacteria can be used for removing selenate and nitrate from mine wastewater. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  5. Latitudinal and seasonal variations of lower atmospheric inertial gravity wave energy revealed by US radiosonde data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.D.; Yi, F. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Huang, C.M. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Miami Univ., Oxford, OH (United States). Electrical and Computer Engineering Dept.; Zhou, Q. [Miami Univ., Oxford, OH (United States). Electrical and Computer Engineering Dept.

    2010-07-01

    The latitudinal and seasonal variations of gravity wave (GW) potential energy density (E{sub P}), kinetic energy density (E{sub K}), and total energy density (E{sub T}), i.e, the sum of potential and kinetic energy densities in the tropospheric (typically 2-10 km) and lower stratospheric (typically 18- 25 km) segments have been derived from 10 years (1998- 2007) of radiosonde observations over 92 United States stations in the Northern Hemisphere. The latitudinal variation of E{sub P} in the lower stratosphere is in good agreement with satellite observations. However, E{sub K} and E{sub T} in the lower stratosphere are different from satellite observations and the difference is believed to be linked with the latitudinal dependence of GW sources. Our analysis reveals that GW energy properties exhibit distinctive latitudinal and seasonal variations. The upward-propagating GW energy in the troposphere is larger than that in the lower stratosphere at low latitudes but the opposite holds true at high latitudes. The transition latitude, where the upward- propagating energies in the two altitude regions are the same, occurs at 35 N throughout the year. So striking differences between GW activity in the troposphere and lower stratosphere are not likely explained only by the background wind Doppler shifting due to strong tropospheric jets. Our analysis indicates that the region around tropopause, roughly from 10 km to 18 km, is an important source region, especially at latitudes below 35 N. Our studies strongly suggest that in order to fully understand the global GW activity in the lower atmosphere, the GW kinetic energy and its geographical and seasonal variations should be included, and more attention should be given to GWs in the troposphere and GW sources within the intermediate region, especially the upper troposphere. (orig.)

  6. Latitudinal and seasonal variations of lower atmospheric inertial gravity wave energy revealed by US radiosonde data

    Directory of Open Access Journals (Sweden)

    S. D. Zhang

    2010-05-01

    Full Text Available The latitudinal and seasonal variations of gravity wave (GW potential energy density (EP, kinetic energy density (EK, and total energy density (ET, i.e, the sum of potential and kinetic energy densities in the tropospheric (typically 2–10 km and lower stratospheric (typically 18–25 km segments have been derived from 10 years (1998–2007 of radiosonde observations over 92 United States stations in the Northern Hemisphere. The latitudinal variation of EP in the lower stratosphere is in good agreement with satellite observations. However, EK and ET in the lower stratosphere are different from satellite observations and the difference is believed to be linked with the latitudinal dependence of GW sources. Our analysis reveals that GW energy properties exhibit distinctive latitudinal and seasonal variations. The upward-propagating GW energy in the troposphere is larger than that in the lower stratosphere at low latitudes but the opposite holds true at high latitudes. The transition latitude, where the upward- propagating energies in the two altitude regions are the same, occurs at 35° N throughout the year. So striking differences between GW activity in the troposphere and lower stratosphere are not likely explained only by the background wind Doppler shifting due to strong tropospheric jets. Our analysis indicates that the region around tropopause, roughly from 10 km to 18 km, is an important source region, especially at latitudes below 35° N. Our studies strongly suggest that in order to fully understand the global GW activity in the lower atmosphere, the GW kinetic energy and its geographical and seasonal variations should be included, and more attention should be given to GWs in the troposphere and GW sources within the intermediate region, especially the upper troposphere.

  7. Preliminary observations on the effects of selenate on the development of the embryonic skate, Raja eglanteria

    Science.gov (United States)

    Conrad, G. W.; Luer, C. A.; Paulsen, A. Q.; Funderburgh, J. L.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    Morphogenesis of the clearnose skate, Raja eglanteria, was not significantly inhibited as a result of 7 days of exposure to 1-2 mM selenate in the sea water during Days 59-69 of embryonic development (hatching would normally have occurred at 82 +/- 4 days of incubation). Although corneal transparency appeared normal in the eye, preliminary measurements of the thickness of Bowman's layer of the cornea suggested that it was significantly thinner in the corneas of embryos exposed to 1-2 mM selenate. Selenate is an ion reported to inhibit sulfation of glycosaminoglycans in connective tissue.

  8. Observation of Possible Lava Tube Skylights by SELENE cameras

    Science.gov (United States)

    Haruyama, Junichi; Hiesinger, Harald; van der Bogert, Carolyn

    We have discovered three deep hole-structures on the Moon in the Terrain Camera and Multi-band Imager on the SELENE. These holes are large depth to diameter ratios: Marius Hills Hole (MHH) is 65 m in diameter and 88-90 m in depth, Mare Tranquillitatis Hole (MTH) is 120 x 110 m in diameter and 180 m in depth, and Mare Ingenii Hole (MIH) is 140 x 110 m in diameter and deeper than 90 m. No volcanic material from the holes nor dike-relating pit craters is seen around the holes. They are possible lava tube skylights. These holes and possibly connected tubes have a lot of scientific interests and high potentialities as lunar bases.

  9. Infrared absorption spectra of selenate compounds of indium (3)

    International Nuclear Information System (INIS)

    Kharitonov, Yu.Ya.; Kadoshnikova, N.V.; Tananaev, I.V.

    1979-01-01

    Obtained and discussed are infrared absorption spectra (400-4000 cm -1 ) of the following indium selenates: In 2 (SeO 4 ) 3 x5H 2 O, In 2 (SeO 4 ) 3 x9H 2 O, NaIn(SeO 4 ) 2 x6H 2 O, NaIn(SeO 4 ) 2 xH 2 O, MIn(SeO 4 ) 2 x4H 2 O (M=NH 4 , K, Rb), CsIn(SeO 4 ) 2 x2H 2 O, Na 3 In(SeO 4 ) 3 x7H 2 O, MIn(SeO 4 ) 2 (M=NH 4 , Na, K, Rb, Cs), M 2 InOH(SeO 4 ) 2 xyH 2 O (M=NH 4 , Na, K, Rb) and K 2 InOD(SeO 4 ) 2 xyD 2 O

  10. Synthesis, characterization and thermal decomposition of tetramethylammonium rare earth double selenates

    Science.gov (United States)

    Divekar, Sandesh K.; Achary, S. Nagabhusan; Ajgaonkar, Vishnu R.

    2018-06-01

    A series of double selenates, as (CH3)4NLn(SeO4)2rad 4H2O (Ln = Rare earth ion like La, Pr, Nd, Sm, Gd, Tb, Dy) was crystallized from mixed solution and characterized in detail for their structure, vibrational and optical properties as well as thermal stabilities. The crystal structure of the praseodymium compound was obtained by single crystal X-ray diffraction (XRD) and revealed a monoclinic (C2/c) lattice with chains formed by PrO8 and SeO4 units. The chains with compositions [Pr(SeO4)4(H2O)4]- are stacked in three dimensions and the (CH3)4N+ ions located in between them provide charge neutrality to the structure. The characterization of other compounds were carried out from powder XRD data and revealed that they all are isostructural to Pr-compound. All the functional groups were identified by Raman and IR spectroscopic studies. Solid state 77Se NMR revealed noticeable changes in selenium environment in these compounds. The optical absorption studies on the compounds show strong band edge absorptions in UV region. Thermal stabilities of the compounds, as investigated by simultaneous TG-DTA techniques indicate their sequential decompositions due to loss of H2O, (CH3)4N+ group, SeO2 and finally leaving their corresponding rare earth oxides.

  11. Bioavailability of selenium from fish, yeast and selenate: A comparative study in humans using stable isotopes

    NARCIS (Netherlands)

    Fox, T.E.; Heuvel, E.G.H.M. van den; Atherton, C.A.; Dainty, J.R.; Lewis, D.J.; Langford, N.J.; Crews, H.M.; Luten, J.B.; Lorentzen, M.; Sieling, F.W.; Aken-Schneyder, P. van; Hoek, M.; Kotterman, M.J.J.; Dael, P. van; Firweather-Tail, S.J.

    2004-01-01

    Objective: To measure the bioavailability of selenium from cooked and raw fish in humans by estimating and comparing apparent absorption and retention of selenium in biosynthetically labelled fish with labelled selenate and biosynthetically labelled selenium in brewers yeast. Design: The

  12. Bioavailibility of selenium from fish, yeast and selenate: a comparative study in humans using stable isotopes

    NARCIS (Netherlands)

    Fox, T.E.; Heuvel, van den E.G.H.M.; Atherton, C.A.; Luten, J.B.; Hoek-van Nieuwenhuizen, van M.; Kotterman, M.J.J.

    2004-01-01

    Objective: To measure the bioavailability of selenium from cooked and raw fish in humans by estimating and comparing apparent absorption and retention of selenium in biosynthetically labelled fish with labelled selenate and biosynthetically labelled selenium in brewers yeast. Design: The

  13. Optimum Exploration for the Self-Ordering of Anodic Porous Alumina Formed via Selenic Acid Anodizing

    OpenAIRE

    Akiya, Shunta; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2015-01-01

    Improvements of the regularity of the arrangement of anodic porous alumina formed by selenic acid anodizing were investigated under various operating conditions. The oxide burning voltage increased with the stirring rate of the selenic acid solution, and the high applied voltage without oxide burning was achieved by vigorously stirring the solution. The regularity of the porous alumina was improved as the anodizing time and surface flatness increased. Conversely, the purity of the 99.5–99.999...

  14. Ocean to continent transfer of atmospheric Se as revealed by epiphytic lichens

    International Nuclear Information System (INIS)

    Wen Hanjie; Carignan, Jean

    2009-01-01

    There is still a long-term debate concerning the relative contributions of naturally emitted and anthropogenic Se at the regional and local scales. Here, Se and heavy metal concentrations are reported for epiphytic lichens collected in coastal and inland areas from the USA, Canada and France for assessing atmospheric Se source. Correlations found between Se and Cl in lichens confirmed the major marine biogenic source for atmospheric Se. Continental samples do not show systematic relationships between Se and other metal (Pb, Cu, In ...) contents, even for lichens collected in the vicinity of smelters or close to urban areas. Our results suggest that, although anthropogenic Se may be present, the marine biogenic Se source is a major contributor to atmospheric Se for our sampling locations. The contribution of naturally emitted atmospheric Se may be significant in urban and industrial areas and should be taken into account for further studies. - Although anthropogenic Se may be present, the contribution of naturally emitted atmospheric Se may be significant in urban and industrial areas and should be taken into account for further studies.

  15. Broadband and polarization reflectors in the lookdown, Selene vomer.

    Science.gov (United States)

    Zhao, Shulei; Brady, Parrish Clawson; Gao, Meng; Etheredge, Robert Ian; Kattawar, George W; Cummings, Molly E

    2015-03-06

    Predator evasion in the open ocean is difficult because there are no objects to hide behind. The silvery surface of fish plays an important role in open water camouflage. Various models have been proposed to account for the broadband reflectance by the fish skin that involve one-dimensional variations in the arrangement of guanine crystal reflectors, yet the three-dimensional organization of these guanine platelets have not been well characterized. Here, we report the three-dimensional organization and the optical properties of integumentary guanine platelets in a silvery marine fish, the lookdown (Selene vomer). Our structural analysis and computational modelling show that stacks of guanine platelets with random yaw angles in the fish skin produce broadband reflectance via colour mixing. Optical axes of the guanine platelets and the collagen layer are aligned closely and provide bulk birefringence properties that influence the polarization reflectance by the skin. These data demonstrate how the lookdown preserves or alters polarization states at different incident polarization angles. These optical properties resulted from the organization of these guanine platelets and the collagen layer may have implications for open ocean camouflage in varying light fields. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Migration history of air-breathing fishes reveals Neogene atmospheric circulation patterns

    Science.gov (United States)

    Böhme, M.

    2004-05-01

    The migration history of an air-breathing fish group (Channidae; snakehead fishes) is used for reconstructing Neogene Eurasian precipitation and atmospheric circulation patterns. The study shows that snakeheads are sensitive indicators of summer precipitation maxima in subtropical and temperate regions, and are present regularly if the wettest month exceeds 150 mm precipitation and 20 °C mean temperature. The analysis of 515 fossil freshwater fish deposits of the past 50 m.y. from Africa and Eurasia shows two continental-scale migration events from the snakeheads' center of origin in the south Himalayan region, events that can be related to changes in the Northern Hemisphere circulation pattern. The first migration, ca. 17.5 Ma, into western and central Eurasia may have been caused by a northward shift of the Intertropical Convergence Zone that brought western Eurasia under the influence of trade winds that produced a zonal and meridional precipitation gradient in Europe. During the second migration, between 8 and 4 Ma, into Africa and East Asia, snakeheads reached their present-day distribution. This migration could have been related to the intensification of the Asian monsoon that brought summer precipitation to their migratory pathways in East Africa Arabia and East Asia.

  17. Interhemispheric gradient of atmospheric radiocarbon reveals natural variability of Southern Ocean winds

    Science.gov (United States)

    Rodgers, K. B.; Mikaloff-Fletcher, S. E.; Bianchi, D.; Beaulieu, C.; Galbraith, E. D.; Gnanadesikan, A.; Hogg, A. G.; Iudicone, D.; Lintner, B. R.; Naegler, T.; Reimer, P. J.; Sarmiento, J. L.; Slater, R. D.

    2011-10-01

    Tree ring Δ14C data (Reimer et al., 2004; McCormac et al., 2004) indicate that atmospheric Δ14C varied on multi-decadal to centennial timescales, in both hemispheres, over the period between AD 950 and 1830. The Northern and Southern Hemispheric Δ14C records display similar variability, but from the data alone is it not clear whether these variations are driven by the production of 14C in the stratosphere (Stuiver and Quay, 1980) or by perturbations to exchanges between carbon reservoirs (Siegenthaler et al., 1980). As the sea-air flux of 14CO2 has a clear maximum in the open ocean regions of the Southern Ocean, relatively modest perturbations to the winds over this region drive significant perturbations to the interhemispheric gradient. In this study, model simulations are used to show that Southern Ocean winds are likely a main driver of the observed variability in the interhemispheric gradient over AD 950-1830, and further, that this variability may be larger than the Southern Ocean wind trends that have been reported for recent decades (notably 1980-2004). This interpretation also implies that there may have been a significant weakening of the winds over the Southern Ocean within a few decades of AD 1375, associated with the transition between the Medieval Climate Anomaly and the Little Ice Age. The driving forces that could have produced such a shift in the winds at the Medieval Climate Anomaly to Little Ice Age transition remain unknown. Our process-focused suite of perturbation experiments with models raises the possibility that the current generation of coupled climate and earth system models may underestimate the natural background multi-decadal- to centennial-timescale variations in the winds over the Southern Ocean.

  18. Interhemispheric gradient of atmospheric radiocarbon reveals natural variability of Southern Ocean winds

    Directory of Open Access Journals (Sweden)

    K. B. Rodgers

    2011-10-01

    Full Text Available Tree ring Δ14C data (Reimer et al., 2004; McCormac et al., 2004 indicate that atmospheric Δ14C varied on multi-decadal to centennial timescales, in both hemispheres, over the period between AD 950 and 1830. The Northern and Southern Hemispheric Δ14C records display similar variability, but from the data alone is it not clear whether these variations are driven by the production of 14C in the stratosphere (Stuiver and Quay, 1980 or by perturbations to exchanges between carbon reservoirs (Siegenthaler et al., 1980. As the sea-air flux of 14CO2 has a clear maximum in the open ocean regions of the Southern Ocean, relatively modest perturbations to the winds over this region drive significant perturbations to the interhemispheric gradient. In this study, model simulations are used to show that Southern Ocean winds are likely a main driver of the observed variability in the interhemispheric gradient over AD 950–1830, and further, that this variability may be larger than the Southern Ocean wind trends that have been reported for recent decades (notably 1980–2004. This interpretation also implies that there may have been a significant weakening of the winds over the Southern Ocean within a few decades of AD 1375, associated with the transition between the Medieval Climate Anomaly and the Little Ice Age. The driving forces that could have produced such a shift in the winds at the Medieval Climate Anomaly to Little Ice Age transition remain unknown. Our process-focused suite of perturbation experiments with models raises the possibility that the current generation of coupled climate and earth system models may underestimate the natural background multi-decadal- to centennial-timescale variations in the winds over the Southern Ocean.

  19. Atmospheric CO2 measurements reveal strong drought sensitivity of Amazonian carbon balance

    Science.gov (United States)

    Miller, J. B.; Gatti, L.; Gloor, M.; Doughty, C.; Malhi, Y.; Domingues, L. G.; Basso, L. S.; Martinewski, A.; Correia, C.; Borges, V.; Freitas, S. R.; Braz, R.; Anderson, L.; Rocha, H.; Grace, J.; Phillips, O.; Lloyd, J.

    2013-12-01

    Potential feedbacks between land carbon pools and climate are one of the largest sources of uncertainty for predicting future global climate, but estimates of their sensitivity to climate anomalies in the tropics and determination of underlying mechanisms are either incomplete or strongly model-based. Amazonia alone stores ~150-200 Pg of labile carbon, and has experienced an increasing trend in temperature and extreme floods and droughts over the last two decades. Here we report the first Amazon Basin-wide seasonal and annual carbon balances based on tropospheric greenhouse gas sampling, during an anomalously dry and a wet year, 2010 and 2011, providing the first whole-system assessment of sensitivity to such conditions. During 2010, the Amazon Basin lost 0.5×0.2 PgCyr-1 while in 2011 it was approximately carbon neutral (0.06×0.1 PgCyr-1). Carbon loss via fire was 0.5×0.1 PgCyr-1 in 2010 and 0.3×0.1 PgCyr-1 in 2011, as derived from Basin-wide carbon monoxide (CO) enhancements. Subtracting fire emissions from total carbon flux to derive Basin net biome exchange (NBE) reveals that in 2010 the non-fire regions of the Basin were carbon neutral; in 2011 they were a net carbon sink of -0.3×0.1 PgC yr-1, roughly consistent with a three-decade long intact-forest biomass sink of ~ -0.5×0.3 PgCyr-1 estimated from forest censuses. Altogether, our results suggest that if the recent trend of precipitation extremes persists, the Amazon region may become an increasing carbon source as a result of both emissions from fires and suppression of NBE by drought.

  20. Deposition of CuIn(Se,S)2 thin films by sulfurization of selenized Cu/In alloys

    International Nuclear Information System (INIS)

    Sheppard, C.J.; Alberts, V.; Bekker, W.J.

    2004-01-01

    The relatively small band gap values (close to 1eV) of CuInSe 2 thin films limits the conversion efficiencies of completed CuInSe 2 /CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to increase the band gap by substituting indium with gallium. In this study, sputtered copper-indium alloys were exposed to a H 2 Se/Ar atmosphere under defined conditions in order to produce partially reacted CuInSe 2 structures. These films were subsequently exposed to a H 2 S/Ar atmosphere to produce monophasic CuIn(Se, S) 2 quaternary alloys. The homogeneous incorporation of S into CuInSe 2 led to a systematic shift in the lattice parameters and band gap of the ab- sorber films. From these studies optimum selenization/sulfurization conditions were determined for the deposition of homogeneous CuIn(Se,S) 2 thin films with an optimum band gap values between 1.15 and 1.2 eV. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. How the Starting Precursor Influences the Properties of Polycrystalline CuInGaSe2 Thin Films Prepared by Sputtering and Selenization

    Directory of Open Access Journals (Sweden)

    Greta Rosa

    2016-05-01

    Full Text Available Cu(In,GaSe2 (CIGS/CdS thin-film solar cells have reached, at laboratory scale, an efficiency higher than 22.3%, which is one of the highest efficiencies ever obtained for thin-film solar cells. The research focus has now shifted onto fabrication processes, which have to be easily scalable at an industrial level. For this reason, a process is highlighted here which uses only the sputtering technique for both the absorber preparation and the deposition of all the other materials that make up the cell. Particular emphasis is placed on the comparison between different precursors obtained with either In2Se3 and Ga2Se3 or InSe and GaSe as starting materials. In both cases, the precursor does not require any heat treatment, and it is immediately ready to be selenized. The selenization is performed in a pure-selenium atmosphere and only lasts a few minutes at a temperature of about 803 K. Energy conversion efficiencies in the range of 15%–16% are reproducibly obtained on soda-lime glass (SLG substrates. Similar results are achieved if commercial ceramic tiles are used as a substrate instead of glass. This result is especially useful for the so-called building integrated photovoltaic. Cu(In,GaSe2-based solar cells grown directly on ceramic tiles are ideal for the fabrication of ventilated façades in low impact buildings.

  2. Preparation, solubility, infrared spectra and radiolysis of tetramethylammonium hydrogenselenate monohydrate and lithium tetramethylammonium selenate tetrahydrate

    Czech Academy of Sciences Publication Activity Database

    Havlíček, D.; Turek, L.; Plocek, Jiří; Mička, Z.

    2006-01-01

    Roč. 71, č. 3 (2006), s. 411-422 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z40320502 Keywords : tetramethylammonium salts * hydrogenselenates * selenates Subject RIV: CA - Inorganic Chemistry Impact factor: 0.881, year: 2006

  3. A novel selenization technique for fabrication of superconducting FeSex thin film

    International Nuclear Information System (INIS)

    Chai Qinglin; Tu Hailing; Hua Zhiqiang; Wang Lei; Qu Fei

    2011-01-01

    A novel selenization technique was applied to prepare superconducting FeSe x films with pre-set FeS films. The combination of reactive sputtering deposition with elemental diffusion technique would extend to prepare films of other iron-based superconductors. The results of transport measurement got close or greater than that of previous reports. T c,onset and T c,0 got to 10.2 K and 4 K respectively. We believe that increase of the content of Fe 7 Se 8 could not only reduce T c but also slow down the decline of resistivity. A combinative method with reactive sputtering deposition and selenization technique was applied to prepare superconducting FeSe x films on LaAlO 3 substrates successfully. The influence of selenizing temperature on film components was studied. FeSe 0.96 and FeSe films had similar and good performances in transport measurement but little difference in magnetic property. The critical onset temperature got to 11.2 K and T c,0 got to 4 K approximately. X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy were used to analyze the ratio of constituents and morphology of several selenized films. FeSe x film had a porous structure on surface and no well preferred orientation, which were confirmed to have little influence on superconducting properties.

  4. Effect of selenization time on the structural and morphological properties of Cu(In,Ga)Se2 thin films absorber layers using two step growth process

    Science.gov (United States)

    Korir, Peter C.; Dejene, Francis B.

    2018-04-01

    In this work two step growth process was used to prepare Cu(In, Ga)Se2 thin film for solar cell applications. The first step involves deposition of Cu-In-Ga precursor films followed by the selenization process under vacuum using elemental selenium vapor to form Cu(In,Ga)Se2 film. The growth process was done at a fixed temperature of 515 °C for 45, 60 and 90 min to control film thickness and gallium incorporation into the absorber layer film. The X-ray diffraction (XRD) pattern confirms single-phase Cu(In,Ga)Se2 film for all the three samples and no secondary phases were observed. A shift in the diffraction peaks to higher 2θ (2 theta) values is observed for the thin films compared to that of pure CuInSe2. The surface morphology of the resulting film grown for 60 min was characterized by the presence of uniform large grain size particles, which are typical for device quality material. Photoluminescence spectra show the shifting of emission peaks to higher energies for longer duration of selenization attributed to the incorporation of more gallium into the CuInSe2 crystal structure. Electron probe microanalysis (EPMA) revealed a uniform distribution of the elements through the surface of the film. The elemental ratio of Cu/(In + Ga) and Se/Cu + In + Ga strongly depends on the selenization time. The Cu/In + Ga ratio for the 60 min film is 0.88 which is in the range of the values (0.75-0.98) for best solar cell device performances.

  5. Global Lunar Gravity Field Determination Using Historical and Recent Tracking Data in Preparation for SELENE

    Science.gov (United States)

    Goossens, S.; Matsumoto, K.; Namiki, N.; Hanada, H.; Iwata, T.; Tsuruta, S.; Kawano, N.; Sasaki, S.

    2006-12-01

    In the near future, a number of satellite missions are planned to be launched to the Moon. These missions include initiatives by China, India, the USA, as well as the Japanese SELENE mission. These missions will gather a wealth of lunar data which will improve the knowledge of the Moon. One of the main topics to be addressed will be the lunar gravity field. Especially SELENE will contribute to improving the knowledge of the gravity field, by applying 4-way Doppler tracking between the main satellite and a relay satellite, and by applying a separate differential VLBI experiment. These will improve the determination of the global gravity field, especially over the far side and at the lower degrees (mostly for degrees lower than 30), as is shown by extensive simulations of the SELENE mission. This work focuses on the determination of the global lunar gravity field from all available tracking data to this date. In preparation for the SELENE mission, analysis using Lunar Prospector tracking data, as well as Clementine data and historical data from the Apollo and Lunar Orbiter projects is being conducted at NAOJ. Some SMART-1 tracking data are also included. The goal is to combine the good-quality data from the existing lunar missions up to this date with the tracking data from SELENE in order to derive a new lunar gravity field model. The focus therefore currently lies on processing the available data and extracting lunar gravity field information from them. It is shown that the historical tracking data contribute especially to the lower degrees of the global lunar gravity field model. Due to the large gap in tracking data coverage over the far side for the historical data, the higher degrees are almost fully determined by the a priori information in the form of a Kaula rule. The combination with SELENE data is thus expected to improve the estimate for the lower degrees even further, including coverage of the far side. Since historical tracking data are from orbits with

  6. Potentiometric titration of selenic and telluric acids with titanium(III) chloride in nonaqueous solvents

    International Nuclear Information System (INIS)

    Yoshimura, Chozo; Miyamoto, Kiyoshige

    1985-01-01

    Selenic and Telluric acids were titrated potentiometrically with titanium(III) chloride solution by using Pt-Cu · Hg bimetallic electrodes in nonaqueous solvents such as N, N-dimethyl-formamide (DMF), dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA) and the mixtures of these solvents. It was found that selenic and telluric acids were titrated directly at room temperature in DMF solution without hydrochloric acid. The molar ratios of selenic and telluric acids to titanium(III) chloride was 1 : 6. However, the corresponding reactions to SeO 4 2- → SeO 3 2- or TeO 4 2- → TeO 3 2- were not confirmed in the titration curve in DMF. In the titration of selenic acid in mixed solvents of DMF and IPA in 1 : 1 or 1 : 2 ratio, two steps were observed. The first and the second steps were appeared on the titration curve at molar ratios of 1 : 2 and 1 : 6, respectively. It was interpreted that the first step corresponded to the intermediate reaction of SeO 4 2- → SeO 3 2- . Mixed solution of selenic and telluric acids were determined by the proposed method. Three steps were observed on the titration curve. It was interpreted that the first, second and third steps corresponded to the reaction of SeO 4 2- → SeO 3 2- , SeO 3 2- → Se(0), and TeO 4 2- → Te(0), respectively. Less than 5 % of water gave no influence on the titration. (author)

  7. Dehydration-driven evolution of topological complexity in ethylamonium uranyl selenates

    Energy Technology Data Exchange (ETDEWEB)

    Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Krivovichev, Sergey V. [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Tananaev, Ivan G. [Far Eastern Federal University, Suhanova st. 8, 690950 Vladivostok (Russian Federation)

    2017-03-15

    Single crystals of four novel uranyl selenate and selenite-selenate oxysalts with protonated ethylamine molecules, (C{sub 2}H{sub 8}N){sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) (I), (C{sub 2}H{sub 8}N){sub 3}[(UO{sub 2})(SeO{sub 4}){sub 2}(HSeO{sub 4})] (II), (C{sub 2}H{sub 8}N)[(UO{sub 2})(SeO{sub 4})(HSeO{sub 3})] (III), and (C{sub 2}H{sub 8}N)(H{sub 3}O)[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)] (IV) have been prepared by isothermal evaporation from aqueous solutions. Uranyl-containing 1D and 2D units have been investigated using topological approach and information-based complexity measurements that demonstrate the evolution of structural units and the increase of topological complexity with the decrease of H{sub 2}O content. - Graphical abstract: Single crystals of four novel uranyl selenate and selenite-selenate oxysalts with protonated ethylamine molecules have been prepared by isothermal evaporation from aqueous solutions. Structural analysis and information-based topological complexity calculations points to the possible sequence of crystalline phases formation, showing both topological and structural branches of evolution. - Highlights: • Single crystals of four novel uranyl oxysalts were prepared by evaporation method. • The graph theory was used for investigation of topologies of structural units. • Dehydration processes drives the evolution of topological complexity of 1D and 2D structural units.

  8. Uptake of selenate on hydrated and degraded cement: batch and dynamic experiments

    International Nuclear Information System (INIS)

    Rojo, I.; Rovira, I.; Marti, V.; Pablo, J. de; Duro, L.; Gaona, X.; Colas, E.; Grive, M.

    2009-01-01

    The evaluation of selenate sorption and retardation in batch and dynamic experiments on hydrated and degraded cement has been studied. Desorption studies have also been carried in order to assess the reversibility of the sorption process. Sorption data onto degraded cement have been treated assuming the formation of surface complexes, whereas sorption kinetics has been fitted by using a pseudo-first order kinetic equation. Dynamic flow experiments have also been modelled. (authors)

  9. Preparation of CIGS thin films by HiPIMS or DC sputtering and various selenization processes

    Czech Academy of Sciences Publication Activity Database

    Olejníček, Jiří; Hubička, Zdeněk; Kšírová, Petra; Kment, Štěpán; Brunclíková, Michaela; Kohout, Michal; Čada, Martin; Darveau, S.A.; Exstrom, C.L.

    2013-01-01

    Roč. 16, č. 2 (2013), s. 314-319 ISSN 1203-8407 R&D Projects: GA MŠk LH12045 Institutional support: RVO:68378271 Keywords : CIGS * HIPIMS * selenization * nanocrystals * solar energy * sputtering * thin films Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.106, year: 2013 http://www.ingentaconnect.com/content/stn/jaots/2013/00000016/00000002/art00015

  10. Novel in situ resistance measurement for the investigation of CIGS growth in a selenization process

    International Nuclear Information System (INIS)

    Liu Wei; He Qing; Li Fengyan; Li Changjian; Sun Yun; Tian Jianguo; Li Zubin

    2009-01-01

    During the selenization process of CIGS thin films, the relation between the element loss rate and the precursor depositions are analyzed. The growth of the CIGS thin films during the selenization process is investigated by the novel in situ resistance measurement, by which the formation of compound semiconductors can be observed directly and simultaneously. Their structures, phase evolutions and element losses are analyzed by XRD and XRF. Based on the experimental results, it can be concluded that the phase transforms have nothing to do with the deposition sequences of precursors, while the element loss rates are related to the deposition sequences in this process. In addition, element loss mechanisms of CIGS thin films prepared by the selenization process are analyzed by the phase evolutions and chemical combined path in the In, Ga–Se reaction processes. Moreover it is verified that the element losses are depressed by increasing the ramping-up rate finally. The results provide effective methods to fabricate high-quality CIGS thin films with low element losses

  11. Novel in situ resistance measurement for the investigation of CIGS growth in a selenization process

    Science.gov (United States)

    Liu, Wei; Tian, Jian-Guo; Li, Zu-Bin; He, Qing; Li, Feng-Yan; Li, Chang-Jian; Sun, Yun

    2009-03-01

    During the selenization process of CIGS thin films, the relation between the element loss rate and the precursor depositions are analyzed. The growth of the CIGS thin films during the selenization process is investigated by the novel in situ resistance measurement, by which the formation of compound semiconductors can be observed directly and simultaneously. Their structures, phase evolutions and element losses are analyzed by XRD and XRF. Based on the experimental results, it can be concluded that the phase transforms have nothing to do with the deposition sequences of precursors, while the element loss rates are related to the deposition sequences in this process. In addition, element loss mechanisms of CIGS thin films prepared by the selenization process are analyzed by the phase evolutions and chemical combined path in the In, Ga-Se reaction processes. Moreover it is verified that the element losses are depressed by increasing the ramping-up rate finally. The results provide effective methods to fabricate high-quality CIGS thin films with low element losses.

  12. Subsurface structures in the northern Mare Imbrium measured by Chang'E-3 and SELENE

    Science.gov (United States)

    Kumamoto, A.; Ishiyama, K.; Feng, J.

    2016-12-01

    Subsurface structures in the northern Mare Imbrium measured by Chang'E-3 and SELENE have been compared. In Chang'E-3 mission, subsurface radar sounding at (19.51W, 44.12N) was performed by Lunar Penetrating Radar (LPR) onboard the Yutu rover. The LPR was pulse radar operated at two frequencies: 60 MHz and 500 MHz. During its operation period from December 2013 to January 2014, the LPR observed subsurface echoes along the rover's track with total distance of 114 m. From the observation in 60 MHz, the subsurface echoes from buried regolith layers at depths of 35, 50, 140, 240, and 360 m were reported (Xiao et al., 2015). In SELENE mission, global subsurface radar sounding of the moon was performed by Lunar Radar Sounder (LRS) onboard the SELENE (Kaguya) spacecraft from the polar orbit with an altitude of 100 km. The LRS was chirp radar operated in a frequency range from 4-6 MHz. So the range resolution of LRS was 75 m in vacuum. During operation period from December 2007 to September 2008, subsurface echoes from all areas of the Moon was observed with a lateral resolution of 76 m. From the global observation, the subsurface echoes from the buried regolith layers in the neraside maria including Mare Imbrium at depths of several hundred meters were reported (Ono et al., 2009).In the present study, we focus on SELENE/LRS data obtained at (19.50W, 44.12N) which is the nearest to the Chang'E-3 landing site. While clear and large-scale subsurface reflectors, as found in Ono et al. (2009), are not found in it, we can identify some echo components from the depths of 140 ( 2000 ns), 240 ( 4000 ns), and 360 m ( 6000 ns). Further analyses utilizing high-resolution data from Chang'E-3/LPR and large-scale data from SELENE/LRS, we will be able to determine the thickness and large-scale structures of the buried regolith layers found by the both radars, and discuss their formation processes in volcanic history of Mare Imbrium.

  13. Study of Pitch Attitude Estimation Using a High-Definition TV (HDTV) Camera on the Japanese Lunar Explorer SELENE (KAGUYA)

    Science.gov (United States)

    Sobue, Shinichi; Yamazaki, Junichi; Matsumoto, Shuichi; Konishi, Hisahiro; Maejima, Hironori; Sasaki, Susumu; Kato, Manabu; Mitsuhashi, Seiji; Tachino, Junichi

    The lunar explorer SELENE (also called KAGUYA) carried thirteen scientific mission instruments to reveal the origin and evolution of Moon and to investigate the possible future utilization of Moon. In addition to the scientific instruments, a high-definition TV (HDTV) camera provided by the Japan Broadcasting Corporation (NHK) was carried on KAGUYA to promote public outreach. We usually use housekeeping telemetry data to derive the satellite attitude along with orbital determination and propagated information. However, it takes time to derive this information, since orbital determination and propagation calculation require the use of the orbital model. When a malfunction of the KAGUYA reaction wheel occurred, we could not have correct attitude information. This means that we don’t have a correct orbital determination in timely fashion. However, when we checked HDTV movies, we found that horizon information on the lunar surface derived from HDTV moving images as a horizon sensor was very useful for the detection of the attitude of KAGUYA. We then compared this information with the attitude information derived from orbital telemetry to validate the accuracy of the HDTV derived estimation. As a result of this comparison, there are good pitch attitude estimation using HDTV derived estimation and we could estimate the pitch angle change during the KAGUYA mission operation simplify and quickly. In this study, we show the usefulness of this HDTV camera as a horizon sensor.

  14. Contribution of SELENE-2 geodetic measurements to constrain the lunar internal structure

    Science.gov (United States)

    Matsumoto, K.; Kikuchi, F.; Yamada, R.; Iwata, T.; Kono, Y.; Tsuruta, S.; Hanada, H.; Goossens, S. J.; Ishihara, Y.; Kamata, S.; Sasaki, S.

    2012-12-01

    Internal structure and composition of the Moon provide important clue and constraints on theories for how the Moon formed and evolved. The Apollo seismic network has contributed to the internal structure modeling. Efforts have been made to detect the lunar core from the noisy Apollo data (e.g., [1], [2]), but there is scant information about the structure below the deepest moonquakes at about 1000 km depth. On the other hand, there have been geodetic studies to infer the deep structure of the Moon. For example, LLR (Lunar Laser Ranging) data analyses detected a displacement of the lunar pole of rotation, indicating that dissipation is acting on the rotation arising from a fluid core [3]. Bayesian inversion using geodetic data (such as mass, moments of inertia, tidal Love numbers k2 and h2, and quality factor Q) also suggests a fluid core and partial melt in the lower mantle region [4]. Further improvements in determining the second-degree gravity coefficients (which will lead to better estimates of moments of inertia) and the Love number k2 will help us to better constrain the lunar internal structure. Differential VLBI (Very Long Baseline Interferometry) technique, which was used in the Japanese lunar exploration mission SELENE (Sept. 2007 - June 2009), is expected to contribute to better determining the second-degree potential Love number k2 and low-degree gravity coefficients. SELENE will be followed by the future lunar mission SELENE-2 which will carry both a lander and an orbiter. We propose to put the SELENE-type radio sources on these spacecraft in order to accurately estimate k2 and the low-degree gravity coefficients. By using the same-beam VLBI tracking technique, these parameters will be retrieved through precision orbit determination of the orbiter with respect to the lander which serves as a reference. The VLBI mission with the radio sources is currently one of the mission candidates for SELENE-2. We have conducted a preliminary simulation study on the

  15. Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Lobinski, R.; Burger-Meyer, K.

    2006-01-01

    The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic...... in garlic. The selenium content in garlic, which was analysed by ICP-MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 mu g g(-1) (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content...... of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of gamma...

  16. Determination of selenite and selenate in human urine by ion chromatography and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jons, O.

    2000-01-01

    The selenium species selenite, selenate and selenomethionine were separated in aqueous solution by ion chromatography. The separation was performed on an IonPac AG11 in series with an AS11 anion exchange column by elution with 25 mM sodium hydroxide in 2% methanol. The Se-78 and Se-82 isotopes were...... monitored in the inductively coupled plasma mass spectrometry (ICP-MS) detector. When the chromatographic system was applied to analysis of urine samples diluted 1 + 1, the selenomethionine signal appeared in the front together with other unresolved selenium species, while the selenite and selenate signals...... and selenate, respectively, corresponding to absolute amounts of 8 and 16 pg, respectively. Calculations were based on peak height measurements of the Se-82 isotope. In 23 analysed urine samples, the concentration of selenite was in the range selenium...

  17. Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

    Science.gov (United States)

    Kassem, M. E.; Hamed, A. E.; Abulnasr, L.; Abboudy, S.

    1994-11-01

    Isotopic effects in pure and γ-irradiated triglycine selenate crystals were investigated using the specific heat ( Cp) technique. The obtained results showed an interesting dependence of the critical behavior of Cp on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order (γ-type) to a first order transition. After γ-irradiation, the behavior of Cp around the phase transition region was essentially affected. The transition temperature, Tc, decreased and Δ Cp depressed, and the transition became broad. It was noted that the effect of γ-irradiation is opposite to the isotopic effect.

  18. Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

    International Nuclear Information System (INIS)

    Kassem, M.E.; Hamed, A.E.; Abulnasr, L.; Abboudy, S.

    1994-01-01

    Isotopic effects in pure and γ-irradiated triglycine selenate crystals were investigated using the specific heat (C p ) technique. The obtained results showed an interesting dependence of the critical behavior of C p on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order (λ-type) to a first order transition. After γ-irradiation, the behavior of C p around the phase transition region was essentially affected. The transition temperature, T c , decreased and ΔC p depressed, and the transition became broad. It was noted that the effect of γ-irradiation is opposite to the isotopic effect. (author)

  19. Influence of selenite and selenate supplementation on the chromium uptake and translocation in Allium cepa

    International Nuclear Information System (INIS)

    Karuna Shanker; Setia, Seema; Srivastava, Shalini; Dass, Sahab; Srivastava, Rohit; Satya Prakash; Srivastava, M.M.

    1997-01-01

    Pot experiments were conducted on onion plant to study the effects of selenite and selenate treatments (0.5-6.0) μg ml -1 on the uptake and translocation of root absorbed chromium irrigated with 2 and 5 μg ml -1 of chromium in sand and soil. Both the form of selenium (SeO 3 2- , and SeO 4 2- ) were found equally effective in reducing the chromium burden of the plant. No significant difference (p>0.05) in dry matter yields among various selenium treatments exist suggesting no salt injury occurred in the plants under prevailing conditions. (author). 10 refs., 1 tab

  20. Effect of selenization conditions on the growth and properties of Cu2ZnSn(S,Se)4 thin films

    OpenAIRE

    Ranjbar, Samaneh; Rajesh Menon, M.R.; Fernandes, P.A.; da Cunha, A.F.

    2015-01-01

    The opto-electronic properties of copper zinc tin sulfide can be tuned to achieve better cell efficiencies by controlled incorporation of selenium. In this paper we report the growth of Cu2ZnSn(S,Se)4 (CZTSSe) using a hybrid process involving the sequential evaporation of Zn and sputtering of the sulfide precursors of Cu and Sn, followed by a selenization step. Two approaches for selenization were followed, one using a tubular furnace and the other using a rapid thermal processor. The effects...

  1. Separation of selenium compounds by CE-ICP-MS in dynamically coated capillaries applied to selenized yeast samples

    DEFF Research Database (Denmark)

    Bendahl, Lars; Gammelgaard, Bente

    2004-01-01

    The selenium species in nutritional supplement tablets, based on selenized yeast, were separated by capillary zone electrophoresis using capillaries coated dynamically with poly(vinyl sulfonate) and detected by ICP-MS. Sample pre-treatment consisted of cold-water extraction by sonication and subs......The selenium species in nutritional supplement tablets, based on selenized yeast, were separated by capillary zone electrophoresis using capillaries coated dynamically with poly(vinyl sulfonate) and detected by ICP-MS. Sample pre-treatment consisted of cold-water extraction by sonication...

  2. Atmospheric CO2 Observations Reveal Strong Correlation Between Regional Net Biospheric Carbon Uptake and Solar-Induced Chlorophyll Fluorescence

    Science.gov (United States)

    Shiga, Yoichi P.; Tadić, Jovan M.; Qiu, Xuemei; Yadav, Vineet; Andrews, Arlyn E.; Berry, Joseph A.; Michalak, Anna M.

    2018-01-01

    Recent studies have shown the promise of remotely sensed solar-induced chlorophyll fluorescence (SIF) in informing terrestrial carbon exchange, but analyses have been limited to either plot level ( 1 km2) or hemispheric/global ( 108 km2) scales due to the lack of a direct measure of carbon exchange at intermediate scales. Here we use a network of atmospheric CO2 observations over North America to explore the value of SIF for informing net ecosystem exchange (NEE) at regional scales. We find that SIF explains space-time NEE patterns at regional ( 100 km2) scales better than a variety of other vegetation and climate indicators. We further show that incorporating SIF into an atmospheric inversion leads to a spatial redistribution of NEE estimates over North America, with more uptake attributed to agricultural regions and less to needleleaf forests. Our results highlight the synergy of ground-based and spaceborne carbon cycle observations.

  3. Selen og vitamin E til søer og pattegrise

    DEFF Research Database (Denmark)

    Nielsen, H. E.; Danielsen, V.; Simesen, M. G.

    1977-01-01

    Formålet med dette forsøg var at undersøge virkningen af foderets selen- og vitamin E indhold på søernes frugtbarhed og pattegrisenes levedygtighed og vækst. Endvidere at undersøge koncentrationen af selen (Se) og vitamin E i råmælk, somælk og blod i relation til foderet. Der forekom enkelte...... dødsfald blandt grisene, som kunne sættes i forbindelse med enten lavt Se-indhold eller lavt vitamin E indhold i foderet. Der blev desuden konstateret flere brunst- og drægtighedsproblemer hos søer, derfik foder med det lave indhold af vitamin E end hos søer i de andre grupper. En forøgelse af Se......-indholdet fra 30 til 60 µg pr. kg foder gav en fordobling af indholdet i råmælk og i somælk. En forøgelse af vitamin E indholdet i foderet fra ca. 20 mg til ca. 45 mg pr. kg foder gav 4 gange forøgelse i råmælk og somælk. Der blev konstateret tilsvarende virkninger af Se og vitamin E i foderet på indholdet i...

  4. Combination cancer treatment through photothermally controlled release of selenous acid from gold nanocages.

    Science.gov (United States)

    Cheng, Haoyan; Huo, Da; Zhu, Chunlei; Shen, Song; Wang, Wenxia; Li, Haoxuan; Zhu, Zhihong; Xia, Younan

    2018-04-03

    Selenite, one of the inorganic forms of selenium, is emerging as an attractive chemotherapeutic agent owing to its selectivity in eradicating cancer cells. Here we demonstrate a new formulation of nanomedicine based on selenous acid, which is mixed with lauric acid (a phase-change material with a melting point around 43 °C) and then loaded into the cavities of Au nanocages. The Au nanocages can serve as a carrier during cell endocytosis and then as a photothermal agent to melt the lauric acid upon the irradiation with a near-infrared laser, triggering the swift release of selenous acid. The photothermal and chemo therapies can also work synergistically, leading to enhanced destruction of cancer cells relative to normal cells. Our systematic study suggests that the impaired mitochondrial function arising from the ROS generated through combination treatment is responsible for the cell death. This study offers an appealing candidate that holds great promise for synergistic cancer treatment. Published by Elsevier Ltd.

  5. From zinc selenate to zinc selenide nano structures synthesized by reduction process

    International Nuclear Information System (INIS)

    Hutagalung, S.D.; Eng, S.T.; Ahmad, Z.A.; Ishak Mat; Yussof Wahab

    2009-01-01

    One-dimensional nano structure materials are very attractive because of their electronic and optical properties depending on their size. It is well known that properties of material can be tuned by reducing size to nano scale because at the small sizes, that they behave differently with its bulk materials and the band gap will control by the size. The tunability of the band gap makes nano structured materials useful for many applications. As one of the wide band gaps semiconductor compounds, zinc selenide (ZnSe) nano structures (nanoparticles, nano wires, nano rods) have received much attention for the application in optoelectronic devices, such as blue laser diode, light emitting diodes, solar cells and IR optical windows. In this study, ZnSe nano structures have been synthesized by reduction process of zinc selenate using hydrazine hydrate (N 2 H 4 .2H 2 O). The reductive agent of hydrazine hydrate was added to the starting materials of zinc selenate were heat treated at 500 degree Celsius for 1 hour under argon flow to form one-dimensional nano structures. The SEM and TEM images show the formation of nano composite-like structure, which some small nano bar and nano pellets stick to the rod. The x-ray diffraction and elemental composition analysis confirm the formation of mixture zinc oxide and zinc selenide phases. (author)

  6. Detection of over 100 selenium metabolites in selenized yeast by liquid chromatography electrospray time-of-flight mass spectrometry.

    Science.gov (United States)

    Gilbert-López, Bienvenida; Dernovics, Mihaly; Moreno-González, David; Molina-Díaz, Antonio; García-Reyes, Juan F

    2017-08-15

    The characterization of the selenometabolome of Selenized(Se)-yeast, that is the fraction of water soluble low-molecular weight Se-metabolites produced in Se-yeast is of paramount interest to expand the knowledge on the composition of this food supplement. In this work, we have applied liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) to search for Se-species from the low molecular weight range fraction of the selenized yeast used for food supplements. Prior to LC-TOFMS, sample treatment consisted of ultrasound assisted water extraction followed by size exclusion fractionation assisted with off-line inductively coupled plasma mass spectrometry detection of isotope 82 Se. The fraction corresponding to low-molecular weight species was subjected to LC-TOFMS using electrospray ionization in the positive ion mode. The detection of the suspected selenized species has been based on the information obtained from accurate mass measurements of both the protonated molecules and fragments from in-source CID fragmentation; along with the characteristic isotope pattern exhibited by the presence of Se. The approach enables the detection of 103 selenized species, most of them not previously reported, in the range from ca. 300-650Da. Besides the detection of selenium species, related sulphur derivate metabolites were detected based on the accurate mass shift due to the substitution of sulphur and selenium. Copyright © 2017. Published by Elsevier B.V.

  7. Uptake and specification of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

    NARCIS (Netherlands)

    Larsen, E.H.; Lobinski, R.; Burger-Meijer, K.; Hansen, M.; Ruzik, R.; Mazurowska, L.; Rasmussen, P.H.; Sloth, J.J.; Scholten, O.E.; Kik, C.

    2006-01-01

    The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic

  8. Sudden increase in atmospheric concentration reveals strong coupling between shoot carbon uptake and root nutrient uptake in young walnut trees

    International Nuclear Information System (INIS)

    Delaire, M.; Sigogne, M.; Beaujard, F.; Frak, E.; Adam, B.; Le Roux, X.

    2005-01-01

    Short-term effects of a sudden increase in carbon dioxide concentration on nutrient uptake by roots during vegetative growth was studied in young walnut trees. Rates of carbon dioxide uptake and water loss by individual trees were determined by a branch bag method from three days before and six days after carbon dioxide concentration was increased. Nutrient uptake rates were measured concurrently by a hydroponic recirculating nutrient solution system. Carbon dioxide uptake rates increased greatly with increasing atmospheric carbon dioxide; nutrient uptake rates were proportional to carbon dioxide uptake rates, except for the phosphorus ion. Daily water loss rates were only slightly affected by elevated carbon dioxide. Overall, it was concluded that in the presence of non-limiting supplies of water and nutrients, root nutrient uptake and shoot carbon assimilation are strongly coupled in the short term in young walnut trees despite the important carbon and nutrient storage capacities od woody species. 45 refs., 7 figs

  9. Investigation into the dehydration of selenate doped Na2M(SO4)2·2H2O (M = Mn, Fe, Co and Ni): Stabilisation of the high Na content alluaudite phases Na3M1.5(SO4)3-1.5x(SeO4)1.5x (M = Mn, Co and Ni) through selenate incorporation

    Science.gov (United States)

    Driscoll, L. L.; Kendrick, E.; Knight, K. S.; Wright, A. J.; Slater, P. R.

    2018-02-01

    In this paper we report an investigation into the phases formed on dehydration of Na2M(SO4)2-x(SeO4)x·2H2O (0 ≤ x ≤ 1; M = Mn, Fe, Co and Ni). For the Fe series, all attempts to dehydrate the samples doped with selenate resulted in amorphous products, and it is suspected that a side redox reaction involving the Fe and selenate may be occurring leading to phase decomposition and hence the lack of a crystalline product on dehydration. For M = Mn, Co, Ni, the structure observed was shown to depend upon the transition metal cation and level of selenate doping. An alluaudite phase, Na3M1.5(SO4)3-1.5x(SeO4)1.5x, was observed for the selenate doped compositions, with this phase forming as a single phase for x ≥ 0.5 M = Co, and x = 1.0 M = Ni. For M = Mn, the alluaudite structure is obtained across the series, albeit with small impurities for lower selenate content samples. Although the alluaudite-type phases Na2+2y(Mn/Co)2-y(SO4)3 have recently been reported [1,2], doping with selenate appears to increase the maximum sodium content within the structure. Moreover, the selenate doped Ni based samples reported here are the first examples of a Ni sulfate/selenate containing system exhibiting the alluaudite structure.

  10. The study of complex equilibria of uranium(VI) with selenate

    International Nuclear Information System (INIS)

    Lubal, P.; Havel, J.

    1997-01-01

    Uranyl (M)-selenate (L) complex equilibria in solution were investigated by spectrophotometry in visible range and potentiometry by means of uranyl ion selective electrode. The formation ML and ML 2 species was proved and the corresponding stability constants calculated were: log β 1 = 1.57 6 ± 0.01 6 , log β 2 = 2.42 3 ± 0.01 3 (I 3.0 mol 1 -1 Na(ClO 4 , SeO 4 ) (spectrophotometry) at 298.2 K. Using potentiometry the values for infinite dilution (I → 0 mol 1 -1 ) were: log β 1 = 2.64 ± 0.01, log β 2 ≤ 3.4 at 298.2 K. Absorption spectra of the complexes were calculated and analysed by deconvolution technique. Derivative spectrophotometry for the chemical model determination has also been successfully applied. (author)

  11. Sorption mechanisms of selenium species (selenite and selenate) on copper-based minerals

    International Nuclear Information System (INIS)

    Devoy, J.

    2001-09-01

    The sorption of radionuclides on the surface of minerals represents a process capable to delay the migration of the elements from a spent fuel deep repository towards the biosphere. In the framework of a deep underground repository, an engineered clay barrier has a high trapping capacity for cationic radio-elements, in particular because of the negative charge of clay surfaces. However, anionic radioelements like selenium species, would be only weakly retained by chemical processes. In order to optimize the trapping capacity of a clay barrier with respect to anionic species, prospective studies are carried out in order to find and evaluate some minerals with specific chemical trapping functions. Among radionuclides, the case of selenium has to be considered because its isotope 79 Se is present in radioactive wastes and has a half life time of 6.5 10 4 years. It is also judicious to find a mineral capable of trapping simultaneously several anionic radio-elements. Copper oxides and sulfides (Cu 2 O, CuO, Cu 2 S, CuS, CuFeS 2 and Cu 5 FeS 4 ) are good adsorbents with respect to selenium species (selenite and selenate). These minerals, with their selenium retention properties, could be used also for the decontamination of soils and waters or to process industrial effluents. The sorption mechanisms have been studied in details for copper oxides (Cu 2 O and CuO) with respect to selenite and selenate. Chalcomenite precipitates in acid pH conditions when selenite is added to a Cu 2 O and CuO suspension. Selenate, in contact with cuprite (Cu 2 O) leads also to a selenium-based precipitate in acid pH environment. For higher pH values, selenite and selenate are adsorbed on copper oxides (Cu 2 O and CuO) and lead to internal and external sphere complexes, respectively. In the case of a selenite/cuprite mixture in basic pH environment and at the equilibrium, a chemical reaction occurs between the oxidation product of cuprite, Cu(OH) 2 and HSeO 3 . A preliminary study of

  12. Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, M.E.; Hamed, A.E.; Abulnasr, L.; Abboudy, S. [Alexandria Univ. (Egypt). Dept. of Physics

    1994-11-01

    Isotopic effects in pure and {gamma}-irradiated triglycine selenate crystals were investigated using the specific heat (C{sub p}) technique. The obtained results showed an interesting dependence of the critical behavior of C{sub p} on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order ({lambda}-type) to a first order transition. After {gamma}-irradiation, the behavior of C{sub p} around the phase transition region was essentially affected. The transition temperature, T{sub c}, decreased and {Delta}C{sub p} depressed, and the transition became broad. It was noted that the effect of {gamma}-irradiation is opposite to the isotopic effect. (author).

  13. Rover exploration on the lunar surface; a science proposal for SELENE-B mission

    Science.gov (United States)

    Sasaki, S.; Kubota, T.; Akiyama, H.; Hirata, N.; Kunii, Y.; Matsumoto, K.; Okada, T.; Otake, M.; Saiki, K.; Sugihara, T.

    LUNARSURFACE:ASCIENCES. Sasaki (1), T. Kubota (2) , H. Akiyama (1) , N. Hirata (3), Y. Kunii (4), K. Matsumoto (5), T. Okada (2), M. Otake (3), K. Saiki (6), T. Sugihara (3) (1) Department of Earth and Planetary Science, Univ. Tokyo, (2) Institute of Space and Astronautical Sciences, (3) National Space Development Agency of Japan, (4) Department of Electrical and Electronic Engineering, Chuo Univ., (5) National Aerospace Laboratory of Japan, (6) Research Institute of Materials and Resources, Akita Univ. sho@eps.s.u -tokyo.ac.jp/Fax:+81-3-5841-4569 A new lunar landing mission (SELENE-B) is now in consideration in Japan. Scientific investigation plans using a rover are proposed. To clarify the origin and evolution of the moon, the early crustal formation and later mare volcanic processes are still unveiled. We proposed two geological investigation plans: exploration of a crater central peak to discover subsurface materials and exploration of dome-cone structures on young mare region. We propose multi-band macro/micro camera using AOTF, X-ray spectrometer/diffractometer and gamma ray spectrometer. Since observation of rock fragments in brecciaed rocks is necessary, the rover should have cutting or scraping mechanism of rocks. In our current scenario, landing should be performed about 500m from the main target (foot of a crater central peak or a cone/dome). After the spectral survey by multi-band camera on the lander, the rover should be deployed for geological investigation. The rover should make a short (a few tens meter) round trip at first, then it should perform traverse observation toward the main target. Some technological investigations on SELENE-B project will be also presented.

  14. On the Revealing Firsthand Probing of Ocean-Ice-Atmosphere Interactions off Sabrina Coast During NBP1402

    Science.gov (United States)

    Huber, B. A.; Orsi, A. H.; Zielinski, N. J.; Durkin, W. J., IV; Clark, P.; Wiederwohl, C. L.; Rosenberg, M. A.; Gwyther, D.; Greenbaum, J. S.; Lavoie, C.; Shevenell, A.; Leventer, A.; Blankenship, D. D.; Gulick, S. P. S.; Domack, E. W.

    2014-12-01

    Diverse interactions of winds, currents and ice around Antarctica dictate how, where and when the world's densest waters form and massive floating ice shelves and glaciers melt, as well as control sea surface gas exchange and primary productivity. Compelled by recent rate estimates of East Antarctic Ice Sheet mass loss, we contrast the paths and mixing histories of oceanic waters reaching the continental ice edge off the Sabrina and Adelie coasts relying on the unique set of synoptic shipboard measurements from NBP1402 (swath bathymetry, ADCP, underway CTD). Analysis of historical hydrography and sea ice concentration fields within the Mertz Polynya indicates the apparent effect of evolving ocean-ice-atmosphere interactions on the characteristics of local Shelf Water (SW) sources to current outflow of newly formed Antarctic Bottom Water (AABW). A polynya dominated water mass structure similar to that observed off the Adelie Coast before the removal of the Mertz Ice Tongue was expected to the west of the Dalton Ice Tongue (DIT). However, we found no evidence of dense SW off Sabrina Coast, which may lessen the region's preconceived influence to global meridional overturning. Present sea ice production within the eastern Dalton Polynya is overshadowed by freshwater input to relatively stable interior upper waters. The Antarctic Coastal Current (ACoC) picks up distinct meltwater contributions along the DIT western flank and in front of the Moscow University Ice Shelf (MUIS) and Totten Glacier (TG). Unlike over other highly influential margins to global sea level rise, there is no evidence of local cross-shelf inflow and mixing of warm Circumpolar Deep Water. Relatively cold thermocline waters from the continental slope enter the eastern trough off Sabrina Coast, and they are swiftly steered poleward by complex underlying topography. Meltwater export from beneath the MUIS and TG is observed at newly discovered trenches that effectively constrain sub-cavity inflow to low

  15. Soil water stable isotopes reveal evaporation dynamics at the soil–plant–atmosphere interface of the critical zone

    Directory of Open Access Journals (Sweden)

    M. Sprenger

    2017-07-01

    Full Text Available Understanding the influence of vegetation on water storage and flux in the upper soil is crucial in assessing the consequences of climate and land use change. We sampled the upper 20 cm of podzolic soils at 5 cm intervals in four sites differing in their vegetation (Scots Pine (Pinus sylvestris and heather (Calluna sp. and Erica Sp and aspect. The sites were located within the Bruntland Burn long-term experimental catchment in the Scottish Highlands, a low energy, wet environment. Sampling took place on 11 occasions between September 2015 and September 2016 to capture seasonal variability in isotope dynamics. The pore waters of soil samples were analyzed for their isotopic composition (δ2H and δ18O with the direct-equilibration method. Our results show that the soil waters in the top soil are, despite the low potential evaporation rates in such northern latitudes, kinetically fractionated compared to the precipitation input throughout the year. This fractionation signal decreases within the upper 15 cm resulting in the top 5 cm being isotopically differentiated to the soil at 15–20 cm soil depth. There are significant differences in the fractionation signal between soils beneath heather and soils beneath Scots pine, with the latter being more pronounced. But again, this difference diminishes within the upper 15 cm of soil. The enrichment in heavy isotopes in the topsoil follows a seasonal hysteresis pattern, indicating a lag time between the fractionation signal in the soil and the increase/decrease of soil evaporation in spring/autumn. Based on the kinetic enrichment of the soil water isotopes, we estimated the soil evaporation losses to be about 5 and 10 % of the infiltrating water for soils beneath heather and Scots pine, respectively. The high sampling frequency in time (monthly and depth (5 cm intervals revealed high temporal and spatial variability of the isotopic composition of soil waters, which can be critical

  16. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Elliot, J.L.; Dunham, E.W.; Bosh, A.S.; Slivan, S.M.; Young, L.A.

    1989-01-01

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  17. Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Erik H.; Hansen, Marianne; Rasmussen, Peter Have; Sloth, Jens J. [Danish Institute for Food and Veterinary Research, Department of Food Chemistry, Soeborg (Denmark); Lobinski, Ryszard; Ruzik, Rafal; Mazurowska, Lena [CNRS UMR 5034, Pau (France); Warsaw University of Technology, Department of Analytical Chemistry, Warsaw (Poland); Burger-Meyer, Karin; Scholten, Olga [Wageningen University and Research Centre, Plant Research International (PRI), P.O. Box 16, Wageningen (Netherlands); Kik, Chris [Wageningen University and Research Centre, Plant Research International (PRI), P.O. Box 16, Wageningen (Netherlands); Wageningen University and Research Centre, Centre for Genetic Resources, The Netherlands (CGN), P.O. Box 16, Wageningen (Netherlands)

    2006-07-15

    The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP-MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 {mu}g g{sup -1} (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP-MS detection showed that {gamma}-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of {gamma}-glutamyl-Se-methyl-selenocysteine and {gamma}-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry. (orig.)

  18. Identifying the Impact of E-Selen on the Sterile Medfly Ceratitis capitata at the Genomic Level Using DNA Profile

    International Nuclear Information System (INIS)

    Zaghloul, Y.S.

    2014-01-01

    The antioxidant E-Selen is an exogenous antioxidant containing both selenium and vitamin E. It was added to the larval artificial diets of the Mediterranean fruit fly, Ceratitis capitata in various concentrations (0.1, 0.3, 0.5 and 1.5 mg) prior to irradiation in order to obtain fully competent males. The produced full grown pupae were exposed to gamma rays at a dose rate of 90 Gy. Biological assessment of two E-Selen concentrations 0.3 and 0.5 mg were found to ameliorate the fitness of the sterile insects as well as to increase significantly most of their amino acids content. The study of the PCR patterns of normal and irradiated C. capitata undertaken or not different doses of E-Selen prior to irradiation and contained in the larval diets induced some modifications to the DNA profiles. The appearance of some new bands and disappearance of others were frequently encountered during this investigation. The appearance of bands was attributed to a repair mechanism that occurs in the irradiated DNA. However, the similarity in the DNA patterns of the homogenate pupal of C. capitata was due to the irradiation-induced damage may be in genome regions other than the regions of study

  19. Optical and structural properties of FeSe2 thin films obtained by selenization of sprayed amorphous iron oxide films

    International Nuclear Information System (INIS)

    Ouertani, B.; Ouerfelli, J.; Saadoun, M.; Zribi, M.; Rabha, M.Ben; Bessais, B.; Ezzaouia, H.

    2006-01-01

    We report in this work the optical and structural properties of iron diselenide films (FeSe 2 ) obtained by selenization under vacuum of amorphous iron oxide films predeposited by spray pyrolysis. The structure of the FeSe 2 films was investigated by scanning electron microscopy (SEM), microprobe analyses, atomic force microscopy (AFM) and X-ray diffraction (XRD). XRD and micro-probe analyses showed that FeSe 2 as well as FeSe 2-x phases begin to appear at a selenization temperature of 500 deg. C. As the selenization temperature rises, the iron diselenide films become more stoichiometric with a dominance of the FeSe 2 phase. At 550 deg. C, a single FeSe 2 phase having good crystallinity was obtained. At 600 deg. C, two phases were detected: the major one corresponds to Fe 3 O 4 , and the minor one to FeSe 2 . SEM surface views show that FeSe 2 films have granular structure with small spherical crystallites. However, layered and clustered FeSe 2 films were found, respectively, at 550 deg. C and 600 deg. C. Absorption measurements show that iron diselenide films have a direct and an indirect gaps of about 1.03 eV and 0.3 eV, which were suggested to be due to the stoichiometric FeSe 2 phase and to a Fe-rich non-stoichiometric phase, respectively

  20. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing

    Science.gov (United States)

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2013-01-01

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing. PMID:24067318

  1. Abiotic pyrite reactivity versus nitrate, selenate and selenite using chemical and electrochemical methods

    International Nuclear Information System (INIS)

    Ignatiadis, I.; Betelu, S.; Gaucher, E.; Tournassat, C.; Chainet, F.

    2010-01-01

    Document available in extended abstract form only. This work is part of ReCosy European project (www.recosy.eu), whose main objectives are the sound understanding of redox phenomena controlling the long-term release/retention of radionuclides in nuclear waste disposal and providing tools to apply the results to performance assessment/safety case. Redox is one of the main factor affecting speciation and mobility of redox-sensitive radionuclides. Thus, it is of a great importance to investigate the redox reactivity of the host radioactive waste formations, particularly when exposed to redox perturbations. Callovo-Oxfordian formation (COx), a clay rock known as an anoxic and reducing system, was selected in France as the most suitable location to store nuclear waste. Iron (II) sulfide, mostly constituted of pyrite (FeS 2 ), iron (II) carbonate, iron(II) bearing clays and organic matter are considered to account almost entirely for the total reducing capacity of the rock. We report here the redox reactivity of pyrite upon exposure to nitrate (N(V)), selenate (Se(VI)) and selenite (Se(IV)) that possibly occur in the nuclear storage. Both, chemical and electrochemical kinetic approaches were simultaneously conducted such as to (i) determine the kinetics parameters of the reactions and (ii) understand the kinetic mechanisms. In order to reach similar conditions that are encountered in the storage system, all experiments were realised in NaCl 0.1 M, near neutral pH solutions, and an abiotic glove box (O 2 less than 10 -8 M). Chemical approach has consisted to set in contact pyrite in grains with solutions containing respectively nitrate, selenate and selenite. Reactants and products chemical analyses, conducted at different contact times, allowed us to assess the kinetics of oxidant reduction. Electrochemical approach has consisted in the continuous or semi-continuous analysis of large surface pyrite electrodes immersed in solutions with or without oxidant (nitrate

  2. Syntheses, characterizations and crystal structures of three new organically templated or organically bonded zinc selenates

    International Nuclear Information System (INIS)

    Feng Meiling; Mao Jianggao; Song Junling

    2004-01-01

    Three new organically templated or organically bonded zinc selenates, namely, {H 2 bipy}Zn(SeO 4 ) 2 (H 2 O) 2 1 (bipy=4,4'-bipyridine), {H 2 pip}{Zn(SeO 4 ) 2 (H 2 O) 4 }·2H 2 O 2 (pip=piprazine), and Zn(SeO 4 )(phen)(H 2 O) 2 3 (phen=1,10-phenanthroline) have been synthesized by hydrothermal reactions. The structure of compound 1 features a 1D chain composed of [Zn(SeO 4 ) 2 (H 2 O) 2 ] 2- anions. Compound 2 has a 2D layer structure built from {Zn(SeO 4 ) 2 (H 2 O) 4 } 2- anions that are cross-linked by doubly protonated piperazine cations via N-H···O hydrogen bonds. The structure of compound 3 contains a 1D chain of Zn(SeO 4 )(phen)(H 2 O) 2 , such chains are further interlinked by hydrogen bonds and π···π interactions to form a layer. The different roles the templates played have also been discussed

  3. Deletion of thioredoxin reductase and effects of selenite and selenate toxicity in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Christopher J Boehler

    Full Text Available Thioredoxin reductase-1 (TRXR-1 is the sole selenoprotein in C. elegans, and selenite is a substrate for thioredoxin reductase, so TRXR-1 may play a role in metabolism of selenium (Se to toxic forms. To study the role of TRXR in Se toxicity, we cultured C. elegans with deletions of trxr-1, trxr-2, and both in axenic media with increasing concentrations of inorganic Se. Wild-type C. elegans cultured for 12 days in Se-deficient axenic media grow and reproduce equivalent to Se-supplemented media. Supplementation with 0-2 mM Se as selenite results in inverse, sigmoidal response curves with an LC50 of 0.20 mM Se, due to impaired growth rather than reproduction. Deletion of trxr-1, trxr-2 or both does not modulate growth or Se toxicity in C. elegans grown axenically, and (75Se labeling showed that TRXR-1 arises from the trxr-1 gene and not from bacterial genes. Se response curves for selenide (LC50 0.23 mM Se were identical to selenite, but selenate was 1/4(th as toxic (LC50 0.95 mM Se as selenite and not modulated by TRXR deletion. These nutritional and genetic studies in axenic media show that Se and TRXR are not essential for C. elegans, and that TRXR alone is not essential for metabolism of inorganic Se to toxic species.

  4. Effect of Sodium Selenate on Hippocampal Proteome of 3×Tg-AD Mice-Exploring the Antioxidant Dogma of Selenium against Alzheimer's Disease.

    Science.gov (United States)

    Iqbal, Javed; Zhang, Kaoyuan; Jin, Na; Zhao, Yuxi; Liu, Qiong; Ni, Jiazuan; Shen, Liming

    2018-04-19

    Selenium (Se), an antioxidant trace element, is an important nutrient for maintaining brain functions and is reported to be involved in Alzheimer's disease (AD) pathologies. The present study has been designed to elucidate the protein changes in hippocampus of 3×Tg-AD mice after supplementing sodium selenate as an inorganic source of selenium. By using iTRAQ proteomics technology, 113 differentially expressed proteins (DEPs) are found in AD/WT mice with 37 upregulated and 76 downregulated proteins. Similarly, in selenate-treated 3×Tg-AD (ADSe/AD) mice, 115 DEPs are found with 98 upregulated and 17 downregulated proteins. The third group of mice (ADSe/WT) showed 75 DEPs with 46 upregulated and 29 downregulated proteins. Among these results, 42 proteins (40 downregulated and 2 upregulated) in the diseased group showed reverse expression when treated with selenate. These DEPs are analyzed with different bioinformatics tools and are found associated with various AD pathologies and pathways. Based on their functions, selenate-reversed proteins are classified as structural proteins, metabolic proteins, calcium regulating proteins, synaptic proteins, signaling proteins, stress related proteins, and transport proteins. Six altered AD associated proteins are successfully validated by Western blot analysis. This study shows that sodium selenate has a profound effect on the hippocampus of the triple transgenic AD mice. This might be established as an effective therapeutic agent after further investigation.

  5. Changes in SeMSC, glucosinolates and sulforaphane levels, and in proteome profile in broccoli (Brassica oleracea var. Italica) fertilized with sodium selenate.

    Science.gov (United States)

    Sepúlveda, Ignacio; Barrientos, Herna; Mahn, Andrea; Moenne, Alejandra

    2013-05-07

    The aim of this work was to analyze the effect of sodium selenate fortification on the content of selenomethyl selenocysteine (SeMSC), total glucosinolates and sulforaphane, as well as the changes in protein profile of the inflorescences of broccoli (Brassica oleracea var. Italica). Two experimental groups were considered: plants treated with 100 μmol/L sodium selenate (final concentration in the pot) and control plants treated with water. Fortification began 2 weeks after transplantation and was repeated once a week during 10 weeks. Broccoli florets were harvested when they reached appropriate size. SeMSC content in broccoli florets increased significantly with sodium selenate fortification; but total glucosinolates and sulforaphane content as well as myrosinase activity were not affected. The protein profile of broccoli florets changed due to fortification with sodium selenate. Some proteins involved in general stress-responses were up-regulated, whereas down-regulated proteins were identified as proteins involved in protection against pathogens. This is the first attempt to evaluate the physiological effect of fortification with sodium selenate on broccoli at protein level. The results of this work will contribute to better understanding the metabolic processes related with selenium uptake and accumulation in broccoli.

  6. Changes in SeMSC, Glucosinolates and Sulforaphane Levels, and in Proteome Profile in Broccoli (Brassica oleracea var. Italica Fertilized with Sodium Selenate

    Directory of Open Access Journals (Sweden)

    Alejandra Moenne

    2013-05-01

    Full Text Available The aim of this work was to analyze the effect of sodium selenate fortification on the content of selenomethyl selenocysteine (SeMSC, total glucosinolates and sulforaphane, as well as the changes in protein profile of the inflorescences of broccoli (Brassica oleracea var. Italica. Two experimental groups were considered: plants treated with 100 mmol/L sodium selenate (final concentration in the pot and control plants treated with water. Fortification began 2 weeks after transplantation and was repeated once a week during 10 weeks. Broccoli florets were harvested when they reached appropriate size. SeMSC content in broccoli florets increased significantly with sodium selenate fortification; but total glucosinolates and sulforaphane content as well as myrosinase activity were not affected. The protein profile of broccoli florets changed due to fortification with sodium selenate. Some proteins involved in general stress-responses were up-regulated, whereas down-regulated proteins were identified as proteins involved in protection against pathogens. This is the first attempt to evaluate the physiological effect of fortification with sodium selenate on broccoli at protein level. The results of this work will contribute to better understanding the metabolic processes related with selenium uptake and accumulation in broccoli.

  7. Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: biogeochemical significance of a novel, sulfate-independent respiration

    Science.gov (United States)

    Oremland, Ronald S.; Hollibaugh, James T.; Maest, Ann S.; Presser, Theresa S.; Miller, Laurence G.; Culbertson, Charles W.

    1989-01-01

    Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO2. A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.

  8. Fabrication of selenization-free superstrate-type CuInS{sub 2} solar cells based on all-spin-coated layers

    Energy Technology Data Exchange (ETDEWEB)

    Cheshme khavar, Amir Hossein [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Gisha Bridge, Tehran (Iran, Islamic Republic of); Mahjoub, Alireza, E-mail: mahjouba@modares.ac.ir [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Gisha Bridge, Tehran (Iran, Islamic Republic of); Samghabadi, Farnaz Safi [Physics Department, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of); Taghavinia, Nima, E-mail: taghavinia@sharif.edu [Physics Department, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of)

    2017-01-15

    Today manufacturing of high efficiency chalcogenide thin film solar cells is based on high cost vacuum-based deposition processes at high temperature (>500 °C) and in chalcogen -containing atmosphere. In this paper, we introduce a simple vacuum-free and selenization-free, solution processing for fabricating a superstrate-type CuInS{sub 2} (CIS) solar cell. The absorber, buffer and blocking layers were all deposited by spin coating of molecular precursor inks. We demonstrate the deposition of In{sub 2}S{sub 3} buffer layer by sol-gel spin casting for the first time. The rapid sintering process of CIS layer was carried out at 250 °C that is considered a very low temperature in CIGS thin-film technologies. A novel molecular-ink route to deposit In{sub 2}S{sub 3} type buffer layer is presented. For the back contact we employed carbon, deposited by simple knife coating method. Different parameters including type of buffer, thickness of absorber layer, CIS and In{sub 2}S{sub 3} annealing temperature and morphology were optimized. Our air stable simple device structure consisting of showed promising power conversion efficiency (PCE) of 2.67%. - Highlights: • This work is an effort on the fabrication of all spin-coated CIS solar cells. • A novel molecular-ink route to deposit In{sub 2}S{sub 3} type buffer layer is presented. • The best devices showed power conversion efficiency (PCE) of 2.67%.

  9. The simulation of lunar gravity field recovery from D-VLBI of Chang’E-1 and SELENE lunar orbiters

    Science.gov (United States)

    Yan, Jianguo; Ping, Jingsong; Matsumoto, K.; Li, Fei

    2008-07-01

    The lunar gravity field is a foundation to study the lunar interior structure, and to recover the evolution history of the Moon. It is still an open and key topic for lunar science. For above mentioned reasons, it becomes one of the important scientific objectives of recent lunar missions, such as KAGUYA (SELENE) the Japanese lunar mission and Chang’E-1, the Chinese lunar mission. The Chang’E-1 and the SELENE were successfully launched in 2007. It is estimated that these two missions can fly around the Moon longer than 6 months simultaneously. In these two missions, the Chinese new VLBI (Very Long Baseline Interferometry) network will be applied for precise orbit determination (POD) by using a differential VLBI (D-VLBI) method during the mission period. The same-beam D-VLBI technique will contribute to recover the lunar gravity field together with other conventional observables, i.e. R&RR (Range and Range Rate) and multi-way Doppler. Taking VLBI tracking conditions into consideration and using the GEODYNII/SOVLE software of GSFC/NASA/USA [Rowlands, D.D., Marshall, J.A., Mccarthy, J., et al. GEODYN II System Description, vols. 1 5. Contractor Report, Hughes STX Corp. Greenbelt, MD, 1997; Ullman, R.E. SOLVE program: mathematical formulation and guide to user input, Hughes/STX Contractor Report, Contract NAS5-31760. NASA Goddard Space Flight Center, Greenbelt, Maryland, 1994], we simulated the lunar gravity field recovering ability with and without D-VLBI between the Chang’E-1 and SELENE main satellite. The cases of overlapped flying and tracking period of 30 days, 60 days and 90 days have been analyzed, respectively. The results show that D-VLBI tracking between two lunar satellites can improve the gravity field recovery remarkably. The results and methods introduced in this paper will benefit the actual missions.

  10. Behaviour of selenate in soils: experimental approach and modeling of hysteresis of sorption/desorption

    International Nuclear Information System (INIS)

    Loffredo, N.

    2010-01-01

    In the context of future storage of nuclear material in deep geological layers, the transfer of selenium-79 from groundwater to biosphere through irrigation is one of the scenarios considered by the ANDRA (National Agency for Radioactive Waste Management). So, the soil would act as an interface between the geosphere and biosphere. Actually the model adopted to evaluate the element mobility in soil is based on a simple representation of its distribution between the quantity adsorbed on the soil and the amount remaining in the solution (KD model). Such distribution is considered as instantaneous, reversible and linear with the concentration of contamination. This model has some inadequacies with respect to selenium because this latter can be present in different redox states that control its mobility and whose transformation kinetics among states are poorly known (Se(-II), Se(0), Se(IV) and Se(VI)). In order to improve predictions on the mobility of selenium in soil, selenate (Se(VI)) - which is the most mobile form - has been used to study its interactions with respect to two different soils (soil B and soil R). A kinetic model, alternative to the K d model, has been developed to describe the evolution of stocks of Se(VI) in solution. This model considers that a fraction of selenium is associated with soil in a reversibly way (potentially mobile) and a portion of it is stabilized in soil (pseudo-irreversibly fixed). This model integrates on one hand, in the soil, kinetics of biotic and abiotic stabilization and on the other hand, in solution, a reduction kinetic. With the goal of acquiring the parameters of the models, various experiments using dialysis bags have been effectuated, both in batch and with open-flow reactors. The parameter acquisition has allowed kinetic and K d models to be compared in different realistic scenarios of contamination (chronic or sequential) of a surface soil with 79 Se(VI). In addition, the sorption mechanisms of Se(VI) have been

  11. A comparative study of APLI and APCI in IMS at atmospheric pressure to reveal and explain peak broadening effects by the use of APLI.

    Science.gov (United States)

    Ihlenborg, Marvin; Raupers, Björn; Gunzer, Frank; Grotemeyer, Jürgen

    2015-11-21

    The details of the ionization mechanism in atmospheric pressure are still not completely known. In order to obtain further insight into the occurring processes in atmospheric pressure laser ionization (APLI) a comparative study of atmospheric pressure chemical ionization (APCI) and APLI is presented in this paper. This study is carried out using similar experimental condition at atmospheric pressure employing a commercial ion mobility spectrometer (IMS). Two different peak broadening mechanisms can then be assigned, one related to a range of different species generated and detected, and furthermore for the first time a power broadening effect on the signals can be identified.

  12. Background electrolytes and pH effects on selenate adsorption using iron-impregnated granular activated carbon and surface binding mechanisms.

    Science.gov (United States)

    Zhang, Ning; Gang, Daniel Dianchen; McDonald, Louis; Lin, Lian-Shin

    2018-03-01

    Iron-impregnated granular activated carbon (Fe-GAC) has been shown effective for selenite adsorptive removal from aqueous solutions, but similar effectiveness was not observed with selenate. This study examined the effects of background electrolytes and pH on selenate adsorption on to Fe-GAC, and surface bindings to elucidate the selenate adsorption mechanisms. The decrease magnitude of selenate adsorption capacity under three background electrolytes followed the order: LiCl > NaCl > KCl, as ionic strength increased from 0.01 to 0.1 M. Larger adsorption capacity differences among the three electrolytes were observed under the higher ionic strengths (0.05 and 0.1 M) than those under 0.01 M. Multiplet peak fittings of high resolution X-ray photoelectron spectra for O1s and Fe2p 3/2 indicated the presence of iron (III) on adsorbent surface. pH variations during the adsorbent preparation within 3-8 in NaCl solutions did not cause appreciable changes in the iron redox state and composition. Raman spectra showed the formation of both monodentate and bidentate inner sphere complexes under pHs adsorption under alkaline conditions. Mechanisms for monodentate and bidentate formations and a stable six-member ring structure were proposed. Two strategies were recommended for modifying Fe-GAC preparation procedure to enhance the selenate adsorption: (1) mixed-metal oxide coatings to increase the point of zero charge (pH zpc ); and (2) ferrous iron coating to initially reduce selenate followed by selenite adsorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium

    International Nuclear Information System (INIS)

    Avoscan, L.

    2007-06-01

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  14. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-01-01

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  15. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-08-08

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  16. An optional focusing SELENE extension to conventional neutron guides: A case study for the ESS instrument BIFROST

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, U.B., E-mail: uhansen@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Bertelsen, M. [Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Stahn, J. [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Lefmann, K. [Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark)

    2017-04-21

    The high brilliance at the European Spallation Source (ESS) will allow for performing experiments with much smaller samples than at present neutron facilities and in much more complex sample environments. However the higher flux also results in higher background from unwanted neutrons not originating from scattering of the sample. We here present a new design idea for beam delivery, where a 165 m ballistic guide system with good transport properties is followed by a 4–8 m SELENE guide system similar to Montel optics used for X-ray optics. We have investigated the system by detailed Monte-Carlo simulations using McStas. We show that under certain conditions, this set-up works surprisingly well, with a brilliance transfer of 20–60% for neutrons of wavelength 4 Å and above. We demonstrate that the guide system is able to focus the beam almost perfectly onto samples sizes in the range of 0.1–2 mm. We furthermore show that our SELENE system is insensitive to gravity and to realistic values of guide waviness. We argue that this guide system can be useful as an optional guide insert when small samples are used in the vicinity of bulky sample environment, e.g. for high-field or high-pressure experiments.

  17. Investigation of stacked elemental layers for Cu(In,Ga)Se{sub 2} thin film preparation by rapid thermal selenization

    Energy Technology Data Exchange (ETDEWEB)

    Stroth, Christiane; Ohland, Joerg; Mikolajczak, Ulf; Madena, Thomas; Keller, Jan; Parisi, Juergen; Hammer, Maria; Riedel, Ingo [Energy and Semiconductor Research Laboratory, Department of Physics, University of Oldenburg, 26111 Oldenburg (Germany)

    2013-07-01

    Rapid thermal selenization of pure metallic (Cu-In-Ga) or selenium-containing (Cu-In-Ga-Se) precursors is a favorable method to fabricate Cu(In,Ga)Se{sub 2} absorber films for application in thin film solar cells. Because of its upscaling potential and the short process time it is a promising approach for the fabrication of CIGSe photovoltaic modules on industrial scale. As a preliminary work for prospective plasma-enhanced selenization of stacked elemental layers (SEL) the elements copper, indium and gallium were sequentially deposited on molybdenum coated soda-lime glass by thermal evaporation. The stacking order was varied and the precursors were annealed with different heating rates. Morphology, elemental depth distribution and phases of the layers were investigated before and after annealing using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Furthermore the influence of different heating rates on phase transitions during annealing was studied by in-situ X-ray diffraction.

  18. Band gap engineering of tandem structured CIGS compound absorption layer fabricated by sputtering and selenization

    Energy Technology Data Exchange (ETDEWEB)

    Kang, San; Sharma, Rahul; Sim, Jae-Kwan [Semiconductor Materials Processing Laboratory, School of Advanced Materials Engineering, College of Engineering, Research Center for Advanced Materials Development (RCAMD), Chonbuk National University, Deokjin-dong 664-14, Jeonju 561-756 (Korea, Republic of); Lee, Cheul-Ro, E-mail: crlee7@jbnu.ac.kr [Semiconductor Materials Processing Laboratory, School of Advanced Materials Engineering, College of Engineering, Research Center for Advanced Materials Development (RCAMD), Chonbuk National University, Deokjin-dong 664-14, Jeonju 561-756 (Korea, Republic of)

    2013-06-25

    Highlights: ► Systematic band gap engineering to fabricate tandem Cu(In,Ga)Se{sub 2} absorption layers. ► XRD shows prominent (1 1 2) reflection shift for attributed CIS, CIGS, and CGS phases. ► Optical transmittance and reflectance spectrum are improved towards infrared region. ► The Cu/In + Ga and Ga/In + Ga effect is matched with highest efficient solar cell. ► Tandem CIS/CIGS/CGS layer, the band gap is increased from 1.15 to 2.06 eV. -- Abstract: Band gap engineering was executed to fabricate a multi-junction stacked i.e. tandem Cu(In,Ga)Se{sub 2} (CIGS) absorption layer. The CIGS absorption layers consist of multi-junction stacked CIS/CIGS/CGS thin films from bottom to top with increasing band gap. Tandem CIGS layers were fabricated by using three precursor of CuIn, In/CuGa/In, and CuGa onto the Mo coated soda-lime glass (SLG) by the sequential sputtering of CuIn, CuGa, and In targets. The CIG precursors were converted into CIGS absorption thin film by selenization process. From the X-ray diffraction (XRD) pattern of CIS/CIGS/CGS tandem layer, with the prominent peak shift for (1 1 2) reflections was attributed to the individual CIS, CIGS, and CGS phases at 26.76°, 27.15°, and 27.65° diffraction angles, respectively. The morphologies and atomic (at%) composition uniformity onto the surface and along the depth were extensively analyzed with field effect scanning electron microscope (FESEM) attached energy dispersive spectroscopy (EDS) and secondary ion mass spectroscopy (SIMS). The optical properties such as transmittance, reflectance and absorbance were found to improve in the infrared region for all the tandem CIGS layers. Near the fundamental absorption edge, the absorption coefficient was approached to 10{sup 5} cm{sup −1} for CIS/CIGS/CGS tandem layer. The straight-line behavior indicates that the films have a direct band gap. The band gap was found to increase from 1.15 to 1.74 eV with the Ga-grading along the depth of individual CIS, CIGS

  19. Band gap engineering of tandem structured CIGS compound absorption layer fabricated by sputtering and selenization

    International Nuclear Information System (INIS)

    Kang, San; Sharma, Rahul; Sim, Jae-Kwan; Lee, Cheul-Ro

    2013-01-01

    Highlights: ► Systematic band gap engineering to fabricate tandem Cu(In,Ga)Se 2 absorption layers. ► XRD shows prominent (1 1 2) reflection shift for attributed CIS, CIGS, and CGS phases. ► Optical transmittance and reflectance spectrum are improved towards infrared region. ► The Cu/In + Ga and Ga/In + Ga effect is matched with highest efficient solar cell. ► Tandem CIS/CIGS/CGS layer, the band gap is increased from 1.15 to 2.06 eV. -- Abstract: Band gap engineering was executed to fabricate a multi-junction stacked i.e. tandem Cu(In,Ga)Se 2 (CIGS) absorption layer. The CIGS absorption layers consist of multi-junction stacked CIS/CIGS/CGS thin films from bottom to top with increasing band gap. Tandem CIGS layers were fabricated by using three precursor of CuIn, In/CuGa/In, and CuGa onto the Mo coated soda-lime glass (SLG) by the sequential sputtering of CuIn, CuGa, and In targets. The CIG precursors were converted into CIGS absorption thin film by selenization process. From the X-ray diffraction (XRD) pattern of CIS/CIGS/CGS tandem layer, with the prominent peak shift for (1 1 2) reflections was attributed to the individual CIS, CIGS, and CGS phases at 26.76°, 27.15°, and 27.65° diffraction angles, respectively. The morphologies and atomic (at%) composition uniformity onto the surface and along the depth were extensively analyzed with field effect scanning electron microscope (FESEM) attached energy dispersive spectroscopy (EDS) and secondary ion mass spectroscopy (SIMS). The optical properties such as transmittance, reflectance and absorbance were found to improve in the infrared region for all the tandem CIGS layers. Near the fundamental absorption edge, the absorption coefficient was approached to 10 5 cm −1 for CIS/CIGS/CGS tandem layer. The straight-line behavior indicates that the films have a direct band gap. The band gap was found to increase from 1.15 to 1.74 eV with the Ga-grading along the depth of individual CIS, CIGS, and CGS thin films

  20. Selenized milk casein in the diet of BALB/c nude mice reduces growth of intramammary MCF-7 tumors

    International Nuclear Information System (INIS)

    Warrington, Jenny M; Kim, Julie JM; Stahel, Priska; Cieslar, Scott RL; Moorehead, Roger A; Coomber, Brenda L; Corredig, Milena; Cant, John P

    2013-01-01

    Dietary selenium has the potential to reduce growth of mammary tumors. Increasing the Se content of cows’ milk proteins is a potentially effective means to increase Se intake in humans. We investigate the effects of selenized milk protein on human mammary tumor progression in immunodeficient BALB/c nude mice. Four isonitrogenous diets with selenium levels of 0.16, 0.51, 0.85 and 1.15 ppm were formulated by mixing low- and high-selenium milk casein isolates with a rodent premix. MCF-7 cells were inoculated into the mammary fat pad of female BALB/c nude mice implanted with slow-release 17 β-estradiol pellets. Mice with palpable tumors were randomly assigned to one of the four diets for 10 weeks, during which time weekly tumor caliper measurements were conducted. Individual growth curves were fit with the Gompertz equation. Apoptotic cells and Bcl-2, Bax, and Cyclin D1 protein levels in tumors were determined. There was a linear decrease in mean tumor volume at 70 days with increasing Se intake (P < 0.05), where final tumor volume decreased 35% between 0.16 and 1.15 ppm Se. There was a linear decrease in mean predicted tumor volume at 56, 63 and 70 days, and the number of tumors with a final volume above 500 mm 3 , with increasing Se intake (P < 0.05). This tumor volume effect was associated with a decrease in the proportion of tumors with a maximum growth rate above 0.03 day -1 . The predicted maximum volume of tumors (V max ) and the number of tumors with a large V max , were not affected by Se-casein. Final tumor mass, Bcl-2, Bax, and Cyclin D1 protein levels in tumors were not significantly affected by Se-casein. There was a significantly higher number of apoptotic cells in high-Se tumors as compared to low-Se tumors. Taken together, these results suggest that turnover of cells in the tumor, but not its nutrient supply, were affected by dairy Se. We have shown that 1.1 ppm dietary Se from selenized casein can effectively reduce tumor progression in an MCF-7

  1. Impact of anthropogenic emission on air quality over a megacity – revealed from an intensive atmospheric campaign during the Chinese Spring Festival

    Directory of Open Access Journals (Sweden)

    K. Huang

    2012-12-01

    Full Text Available The Chinese Spring Festival is one of the most important traditional festivals in China. The peak transport in the Spring Festival season (spring travel rush provides a unique opportunity for investigating the impact of human activity on air quality in the Chinese megacities. Emission sources are varied and fluctuate greatly before, during and after the Festival. Increased vehicular emissions during the "spring travel rush" before the 2009 Festival resulted in high level pollutants of NOx (270 μg m−3, CO (2572 μg m−3, black carbon (BC (8.5 μg m−3 and extremely low single scattering albedo of 0.76 in Shanghai, indicating strong, fresh combustion. Organics contributed most to PM2.5, followed by NO3, NH4+, and SO42−. During the Chinese Lunar New Year's Eve and Day, widespread usage of fireworks caused heavy pollution of extremely high aerosol concentration, scattering coefficient, SO2, and NOx. Due to the "spring travel rush" after the festival, anthropogenic emissions gradually climbed and mirrored corresponding increases in the aerosol components and gaseous pollutants. Secondary inorganic aerosol (SO42−, NO3, and NH4+ accounted for a dominant fraction of 74% in PM2.5 due to an increase in human activity. There was a greater demand for energy as vast numbers of people using public transportation or driving their own vehicles returned home after the Festival. Factories and constructions sites were operating again.

    The potential source contribution function (PSCF analysis illustrated the possible source areas for air pollutants of Shanghai. The effects of regional and long-range transport were both revealed. Five major sources, i.e. natural sources, vehicular emissions, burning of fireworks, industrial

  2. [Pb2F2](SeO4): a heavier analogue of grandreefite, the first layered fluoride selenate

    Science.gov (United States)

    Charkin, Dmitri O.; Plokhikh, Igor V.; Zadoya, Anastasiya I.; Kazakov, Sergey M.; Zaloga, Alexander N.; Kozin, Michael S.; Depmeier, Wulf; Siidra, Oleg I.

    2018-01-01

    Co-precipitation of PbF2 and PbSeO4 in weakly acidic media results in the formation of [Pb2F2](SeO4), the selenate analogue of the naturally occurring mineral grandreefite, [Pb2F2](SO4). The new compound is monoclinic, C2/ c, a = 14.0784(2) Å, b = 4.6267(1) Å, c = 8.8628(1) Å, β = 108.98(1)°, V = 545.93(1) Å3. Its structure has been refined from powder data to R B = 1.55%. From thermal studies, it is established that the compound is stable in air up to about 300 °C, after which it gradually converts into a single phase with composition [Pb2O](SeO4), space group C2/ m, and lattice parameters a = 14.0332(1) Å, b = 5.7532(1) Å, c = 7.2113(1) Å, β = 115.07(1)°, V = 527.37(1) Å3. It is the selenate analogue of lanarkite, [Pb2O](SO4), and phoenicochroite, [Pb2O](CrO4), and its crystal structure was refined to R B = 1.21%. The formation of a single decomposition product upon heating in air suggests that this happens by a thermal hydrolysis mechanism, i.e., Pb2F2SeO4 + H2O (vapor) → Pb2OSeO4 + 2HF↑. This relatively low-temperature process involves complete rearrangement of the crystal structure—from a 2D architecture featuring slabs [Pb2F2]2+ formed by fluorine-centered tetrahedra into a structure characterized by 1D motifs based on [OPb2]2+ chains of oxocentered tetrahedra. The comparative crystal chemistry of the obtained anion-centered structural architectures is discussed.

  3. Cu2ZnSnSe4 Thin Film Solar Cell with Depth Gradient Composition Prepared by Selenization of Sputtered Novel Precursors.

    Science.gov (United States)

    Lai, Fang-I; Yang, Jui-Fu; Chen, Wei-Chun; Kuo, Shou-Yi

    2017-11-22

    In this study, we proposed a new method for the synthesis of the target material used in a two stage process for preparation of a high quality CZTSe thin film. The target material consisting of a mixture of Cu x Se and Zn x Sn 1-x alloy was synthesized, providing a quality CZTSe precursor layer for highly efficient CZTSe thin film solar cells. The CZTSe thin film can be obtained by annealing the precursor layers through a 30 min selenization process under a selenium atmosphere at 550 °C. The CZTSe thin films prepared by using the new precursor thin film were investigated and characterized using X-ray diffraction, Raman scattering, and photoluminescence spectroscopy. It was found that diffusion of Sn occurred and formed the CTSe phase and Cu x Se phase in the resultant CZTSe thin film. By selective area electron diffraction transmission electron microscopy images, the crystallinity of the CZTSe thin film was verified to be single crystal. By secondary ion mass spectroscopy measurements, it was confirmed that a double-gradient band gap profile across the CZTSe absorber layer was successfully achieved. The CZTSe solar cell with the CZTSe absorber layer consisting of the precursor stack exhibited a high efficiency of 5.46%, high short circuit current (J SC ) of 37.47 mA/cm 2 , open circuit voltage (V OC ) of 0.31 V, and fill factor (F.F.) of 47%, at a device area of 0.28 cm 2 . No crossover of the light and dark current-voltage (I-V) curves of the CZTSe solar cell was observed, and also, no red kink was observed under red light illumination, indicating a low defect concentration in the CZTSe absorber layer. Shunt leakage current with a characteristic metal/CZTSe/metal leakage current model was observed by temperature-dependent I-V curves, which led to the discovery of metal incursion through the CdS buffer layer on the CZTSe absorber layer. This leakage current, also known as space charge-limited current, grew larger as the measurement temperature increased and

  4. 大气水汽同位素组成的短期变异特征%Short-term variations of vapor isotope ratios reveal the influence of atmospheric processes

    Institute of Scientific and Technical Information of China (English)

    张世春; 孙晓敏; 王建林; 于贵瑞; 温学发

    2011-01-01

    Stable isotopes of atmospheric water vapor reveal rich information on water movement and phase changes in the atmosphere. Here we presented two nearly continuous time-series of δD and δ18O of atmospheric water vapor (δv) measured at hourly intervals in surface air in Beijing and above a winter wheat canopy in Shijiazhuang using in-situ measurement technique. During the precipitation events, the δv values in both Beijing and Shijiazhuang were in the state of equilibrium with precipitation water, revealing the influence of precipitation processes. However, the δv departures from the equilibrium state were positively correlated with local relative humidity. Note that the δv tended to enrich in Beijing, but deplete in Shijiazhuang during the precipitation events, which mainly resulted from the influence of transpiration processes that enriched the δv in Shijiazhuang. On seasonal time-scale, the δvvalues were log-linear functions of water vapor mixing ratios in both Beijing and Shijiazhuang. The water vapor mixing ratio was an excellent predictor of the δv by the Rayleigh distillation mechanisms, indicating that air mass advection could also play an important role in determining the δv. On a diurnal time-scale, the δv reached the minimum in the early afternoon hours in Beijing which was closely related to the atmospheric processes of boundary layer entrainment. During the peak of growing season of winter wheat, however, the δv reached the minimum in the early morning, and increased gradually through the daytime, and reached the maximum in the late afternoon, which was responsible by the interaction between boundary layer entrainment and the local atmospheric processes, such as transpiration and dew formation. This study has the implications for the important role of vegetation in determining the surface δv and highlights the need to conduct δv measurement on short-term (e.g. diurnal) time scales.

  5. Formation of CuInSe{sub 2} films from metal sulfide and selenide precursor nanocrystals by gas-phase selenization, an in-situ XRD study

    Energy Technology Data Exchange (ETDEWEB)

    Capon, B., E-mail: boris.capon@ugent.be [Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000 Ghent (Belgium); Dierick, R. [Physics and Chemistry of Nanostructures, Ghent University, Krijgslaan 281-S3, B-9000 Ghent (Belgium); Hens, Z. [Physics and Chemistry of Nanostructures, Ghent University, Krijgslaan 281-S3, B-9000 Ghent (Belgium); Center for Nano and Biophotonics, Ghent University, Ghent (Belgium); Detavernier, C. [Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000 Ghent (Belgium)

    2016-08-01

    In this work phase pure CuInSe{sub 2} thin flms were obtained by selenization of ternary CuInSe{sub 2} and CuInS{sub 2} nanocrystals and mixtures of binary nanocrystals such as CuS, In{sub 2}S{sub 3}, Cu{sub 2}Se and In{sub 2}Se{sub 3}. The temperature of the selenium source was kept at 400 °C during selenization. Monitoring the process using in-situ x-ray diffraction, the effect of selenization on the phase formation and grain growth in the precursor film was investigated. Whereas CuInSe{sub 2} and CuInS{sub 2} nanocrystals exhibit little grain growth, we found that mixtures of binary nanocrystals can show significant sintering depending on the reaction conditions. For the mixture of CuS and In{sub 2}S{sub 3} nanocrystals, the crystallinity and the morphology of the obtained fims strongly depends on the Cu/In ratio, with a Cu excess strongly promoting grain growth. With mixtures of Cu{sub 2}Se and In{sub 2}Se{sub 3} nanocrystals the selenium partial pressure plays a crucial role. Selenium evaporation from the mixed compounds results in CuInSe{sub 2} films composed of relatively small crystallites. Higher selenium partial pressures however resulted in improved sintering. Incomplete propagation of the selenization reaction through the layer was observed though, only leading to a well sintered CuInSe{sub 2} top layer above a fine grained bottom layer. - Highlights: • Different types of colloidal nanocrystals were used as precursors to obtain CuInSe{sub 2} films by gas-phase selenization. • In-situ XRD was used to study the effect of selenization on the phase formation and grain growth in the precursor films. • For a mixture of binary metal sulfides the crystallinity and the morphology strongly depend on the Cu/In ratio. • Higher selenium partial pressures result in improved sintering for a mixture of binary metal selenides.

  6. Preparation of Cu{sub 2}ZnSnSe{sub 4} solar cells by low-temperature co-evaporation and following selenization

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Chao, E-mail: chao.gao@kit.edu; Hetterich, Michael [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Schnabel, Thomas; Abzieher, Tobias; Ahlswede, Erik [Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany); Powalla, Michael [Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany); Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany)

    2016-01-04

    Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films are prepared by a two-step method which involves co-evaporation of Cu, Zn, Sn, and Se on molybdenum-coated soda-lime glass at low substrate temperature and a following selenization. Solar cells with efficiencies of up to 6.5% can be achieved. The influence of the selenium deposition rates during co-evaporation and the nitrogen pressure during selenization on the properties of the CZTSe films are investigated. It is found that these two parameters can significantly affect the morphology and crystallinity of the CZTSe films. The possible reasons for the experimental results are discussed.

  7. Selenium deficiency occurs in some patients with moderate-to-severe cirrhosis and can be corrected by administration of selenate but not selenomethionine: a randomized controlled trial123

    Science.gov (United States)

    Burk, Raymond F; Hill, Kristina E; Motley, Amy K; Byrne, Daniel W; Norsworthy, Brooke K

    2015-01-01

    Background: Selenomethionine, which is the principal dietary form of selenium, is metabolized by the liver to selenide, which is the form of the element required for the synthesis of selenoproteins. The liver synthesizes selenium-rich selenoprotein P (SEPP1) and secretes it into the plasma to supply extrahepatic tissues with selenium. Objectives: We conducted a randomized controlled trial to determine whether cirrhosis is associated with functional selenium deficiency (the lack of selenium for the process of selenoprotein synthesis even though selenium intake is not limited) and, if it is, whether the deficiency is associated with impairment of selenomethionine metabolism. Design: Patients with Child-Pugh (C-P) classes A, B, and C (mild, moderate, and severe, respectively) cirrhosis were supplemented with a placebo or supranutritional amounts of selenium as selenate (200 or 400 μg/d) or as selenomethionine (200 μg/d) for 4 wk. Plasma SEPP1 concentration and glutathione peroxidase (GPX) activity, the latter due largely to the selenoprotein GPX3 secreted by the kidneys, were measured before and after supplementation. Results: GPX activity was increased more by both doses of selenate than by the placebo in C-P class B patients. The activity was not increased more by selenomethionine supplementation than by the placebo in C-P class B patients. Plasma selenium was increased more by 400 μg Se as selenate than by the placebo in C-P class C patients. Within the groups who responded to selenate, there was a considerable variation in responses. Conclusion: These results indicate that severe cirrhosis causes mild functional selenium deficiency in some patients that is associated with impaired metabolism of selenomethionine. This trial was registered at clinicaltrials.gov as NCT00271245. PMID:26468123

  8. Community ecology of the metazoan parasites of Atlantic Moonfish, Selene setapinnis (Osteichthyes: Carangidae from the coastal zone of the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    A. S. Cordeiro

    Full Text Available Eighty-nine specimens of Selene setapinnis (Mitchill, 1815 collected from the coastal zone of the State of Rio de Janeiro (21-23ºS, 41-45ºW and 23º05'S, 44º30'W, Brazil, from August 2001 to May 2002, were necropsied to study their metazoan parasites. Eighty-one (91% specimens of S. setapinnis were parasitized by one or more metazoan species. Twenty-one species of parasites were collected: 8 digeneans, 3 monogeneans, 2 cestodes, 5 nematodes, and 3 copepods. The endoparasites (digeneans, cestodes, and nematodes were 74.1% of total number of parasite specimens collected. The monogenean Pseudomazocraes selene (Hargis, 1957 was the most dominant species with the highest prevalence in the parasite community of S. setapinnis. The metazoan parasites of this host species showed the typical aggregated pattern of distribution. Only one parasite species (Acanthocolpoides pauloi Travassos, Freitas & Buhrnheim, 1955 showed positive correlation between the host total length and parasite abundance in S. setapinnis. Caligus robustus Bassett-Smith, 1898, P. selene, and Terranova sp. demonstrated positive correlation between the host total length and prevalence. Larvae of Terranova sp. showed influence of the host sex on its prevalence. A pair of ectoparasite species, P. selene-C. robustus, exhibited positive covariation between their abundances. Two pairs of endoparasite species, L. microstomum-P. merus and A. pauloi-P. merus showed significant covariation among their abundances; and the pair Terranova sp.-Raphidascaris sp. had positive co-ocorrence and covariation in the infracommunities of S. setapinnis. Like the parasite communities of the other carangid fishes from Rio de Janeiro, the parasite community of S. setapinnis is apparently only a slightly ordered species complex, characterized by dominance of endoparasite species.

  9. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  10. Texture control and growth mechanism of WSe{sub 2} film prepared by rapid selenization of W film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongchao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Chongyi Zhangyuan Tungsten Industry Corporation Limited, Ganzhou 341300 (China); Gao, Di; Li, Kun; Pang, Mengde; Xie, Senlin [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Liu, Rutie, E-mail: llrrtt@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Zou, Jianpeng [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2017-02-01

    Highlights: • We present a highly efficient method for preparing WSe{sub 2} film by rapid selenization. • The W film phase composition has little effect on WSe{sub 2} film orientation. • W film density is a critical factor that influences the WSe{sub 2} orientation. • A growth model was proposed for two kinds of WSe{sub 2} film textures. - Abstract: The tungsten diselenide (WSe{sub 2}) films with different orientation present unique properties suitable for specific applications, such as WSe{sub 2} with a C-axis⊥substrate for optoelectronics and WSe{sub 2} with a C-axis // substrate for electrocatalysts. Orientation control of WSe{sub 2} is essential for realizing the practical applications. In this letter, a WSe{sub 2} film has been prepared via rapid selenization of a magnetron-sputtered tungsten (W) film. The influence of the magnetron-sputtered W film on WSe{sub 2} film growth was studied systematically. Scanning electron microscopy, X-ray diffractometry and high-resolution transmission electron microscopy were used to evaluate the morphology, microstructure and phase composition of the W and WSe{sub 2} films. The substrate temperature has a significant effect on the W film phase composition, but little effect on the WSe{sub 2} film orientation. The WSe{sub 2} orientation can be controlled by changing the W film microstructure. A dense W film that is deposited at low pressure is conducive to the formation of WSe{sub 2} with a C-axis⊥substrate, whereas a porous W film deposited at high pressure favors the formation of WSe{sub 2} with a C-axis // substrate. A growth model for the WSe{sub 2} film with different texture has been proposed based on the experimental results. The direction of selenium (Se) vapor diffusion differs at the top and side surfaces. This is a key factor for the preparation of anisotropic WSe{sub 2} films. Highly oriented WSe{sub 2} films with a C-axis⊥substrate grow from the dense W film deposited at low pressure because Se vapor

  11. The Effect of E-Selen Antioxidant on the Fatty Acids Content of the Homogenate of Unirradiated and Irradiated Pupae of Ceratitis Capitata

    International Nuclear Information System (INIS)

    Zaghloul, Y.S.; Abbassy, S.A.; Elakhdar, E.A.H.; Elakhdar, E.A.H.

    2011-01-01

    As antioxidant E-selen was added to the larval artificial diets of the Mediterranean fruit fly, Ceratitis capitata. The produced full grown pupae were exposed to gamma rays at dose rate of 90 Gy. The fatty acid contents of the normal and irradiated insects were analyzed to test to what extent, the uptake of the antioxidant will ameliorate the physiological damage induced to the medfly pupae, as a result of their exposure to irradiation. The results obtained by using Gas-liquid chromatography of fatty acid methyl esters, showed the palmitic and oleic acids to be the most predominant fatty acids in all pupal homogenates in both normal and irradiated pupae, either by the uptake of doses of the E-selen or without. The uptake of E-Selen with a dose of 0.3 mg led to a complete absence of the lauric and myristic acids in the homogenates of the unirradiated pupae of the medfly. This absence of lauric and myristic acids was accompanied by a decrease in the concentrations of the palmitic and linoleic acids reaching 25.17% and 32.98%, respectively as compared to pupae without the uptake of antioxidant. The concentrations of both the stearic and oleic acids showed an obvious increment reaching 199.22% and 58.94%, respectively, relative to those reared on the defined media and no added E.Selen. Exposure of the pupae to a dose of 90 Gy, resulted in an increment in the concentrations of the saturated lauric and myristic acid reaching 96.77% and 34.07%, respectively, relative to the untreated ones. While, at the same dose level, there were decrements in the concentrations of the palmitic, stearic, oleic and linoleic acids with percentages reaching 6.4, 9.22, 3.65 and 1.15%, respectively as compared to unirradiated controls. Irradiation of the pupae with sterilizing dose (90 Gy) after up taking the E-Selen in their larval diets, led to the increase of the concentrations of lauric, oleic and linoleic acids by ratios of 16.82, 8.84 and 29.26%, respectively as compared to their

  12. Local Lunar Gravity Field Analysis over the South Pole-aitken Basin from SELENE Farside Tracking Data

    Science.gov (United States)

    Goossens, Sander Johannes; Ishihara, Yoshiaki; Matsumoto, Koji; Sasaki, Sho

    2012-01-01

    We present a method with which we determined the local lunar gravity field model over the South Pole-Aitken (SPA) basin on the farside of the Moon by estimating adjustments to a global lunar gravity field model using SELENE tracking data. Our adjustments are expressed in localized functions concentrated over the SPA region in a spherical cap with a radius of 45deg centered at (191.1 deg E, 53.2 deg S), and the resolution is equivalent to a 150th degree and order spherical harmonics expansion. The new solution over SPA was used in several applications of geophysical analysis. It shows an increased correlation with high-resolution lunar topography in the frequency band l = 40-70, and admittance values are slightly different and more leveled when compared to other, global gravity field models using the same data. The adjustments expressed in free-air anomalies and differences in Bouguer anomalies between the local solution and the a priori global solution correlate with topographic surface features. The Moho structure beneath the SPA basin is slightly modified in our solution, most notably at the southern rim of the Apollo basin and around the Zeeman crater

  13. Revealed variations of air quality in industrial development over a remote plateau of Southwest China: an application of atmospheric visibility data

    Science.gov (United States)

    Zhao, Tianliang; Liu, Di; Zheng, Xiaobo; Yang, Lexin; Gu, Xiaoping; Hu, Jun; Shu, Zhuozhi; Chang, Jiacheng; Wu, Xiasheng

    2017-12-01

    quality change with less regional transport of air pollutant over YGP during 1980-2010. Implications of the climate change for atmospheric environment will be having potential utility for sustainable development in China.

  14. Jovian atmospheres

    International Nuclear Information System (INIS)

    Allison, M.; Travis, L.D.

    1986-10-01

    A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers

  15. Coupled Effect of Ferrous Ion and Oxygen on the Electron Selectivity of Zerovalent Iron for Selenate Sequestration.

    Science.gov (United States)

    Qin, Hejie; Li, Jinxiang; Yang, Hongyi; Pan, Bingcai; Zhang, Weiming; Guan, Xiaohong

    2017-05-02

    Although the electron selectivity (ES) of zerovalent iron (ZVI) for target contaminant and its utilization ratio (UR) decide the removal capacity of ZVI, little effort has been made to improve them. Taking selenate [Se(VI)] as a target contaminant, this study investigated the coupled influence of aeration gas and Fe(II) on the ES and UR of ZVI. Oxygen was necessary for effective removal of Se(VI) by ZVI without Fe(II) addition. Due to the application of 1.0 mM Fe(II), the ES of ZVI was increased from 3.2-3.6% to 6.2-6.8% and the UR of ZVI was improved by 5.0-19.4% under aerobic conditions, which resulted in a 100-180% increase in the Se(VI) removal capacity by ZVI. Se(VI) reduction by Fe 0 was a heterogeneous redox reaction, and the enrichment of Se(VI) on ZVI surface was the first step of electron transfer from Fe 0 core to Se(VI). Oxygen promoted the generation of iron (hydr)oxides, which facilitated the enrichment of Se(VI) on the ZVI particle surface. Therefore, the high oxygen fraction (25-50%) in the purging gas resulted in only a slight decrease in the ES of ZVI. Fe(II) addition resulted in a pH drop and promoted the generation of lepidocrocite and magnetite, which benefited Se(VI) adsorption and the following electron transfer from underlying Fe 0 to surface-located Se(VI).

  16. Selenium Accumulation Characteristics and Biofortification Potentiality in Turnip (Brassica rapa var. rapa Supplied with Selenite or Selenate

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2018-01-01

    Full Text Available Selenium (Se is an essential trace element for humans. About 70% of the regions in China, including most of the Tibetan Plateau, are faced with Se deficiency problems. Turnip is mainly distributed around the Tibetan Plateau and is one of the few local crops. In the present study, we compared the absorption and translocation differences of Se (IV selenite and Se (VI selenate in turnip. The results showed that Se treatment, either by soil addition (0.2–2 mg Se kg−1 dry soil or by foliar spraying (50–200 mg L−1 Se, could significantly increase the Se concentrations in turnips, and 0.5 mg Se (IV or Se (VI kg−1 dry matter in soils could improve the biomasses of turnips. Moreover, turnip absorbed significantly more Se (VI than Se (IV at the same concentration and also transferred much more Se (VI from roots to leaves. Based on the Se concentrations, as well as the bioconcentration factors and translocation coefficients, we considered that turnip might be a potential Se indicator plant. Subsequently, we estimated the daily Se intake for adults based on the Se concentrations in turnip roots. The results indicated that Se (IV should be more suitable as an artificial Se fertilizer for turnips, although the levels found in most samples in this study could cause selenosis to humans. In addition, we also estimated the optimum and maximum Se concentrations for treating turnips based on the linear relations between Se concentrations in turnip roots and Se treatment concentrations. The results provided preliminary and useful information about Se biofortification in turnips.

  17. THE EFFECTS OF SODIUM SELENITE AND SELENIZED YEAST SUPPLEMENTATION INTO DIET FOR LAYING HENS ON SELECTED QUALITATIVE PARAMETERS OF TABLE EGGS

    Directory of Open Access Journals (Sweden)

    HENRIETA ARPÁŠOVÁ

    2009-10-01

    Full Text Available In this experiment the effects of supplementation of the diet for laying hens with sodium selenite (SS or selenized yeast (SY on whole egg and egg shell quality of layers were studied. The chickens of Shaver Starcross 288 strain were randomly divided at the day of hatching into 4 groups (n=12; in each. The birds were fed from Day 1 of life to 9 months of age with diets differing in amounts and/or forms of selenium. Control group received basal diet (BD containing selenium naturally occurring in feeds (0.1 mg Se/kg of dry matter (DM. First and second experimental group of chickens were fed with a same BD enriched with equivalent dose of Se 0.4 mg/kg DM in form of sodium selenite or selenized yeast, respectively. The feed for third experimental group of birds consisted of BD supplemented with selenized yeast to the final amount of selenium 1.0 mg/kg DM. The egg weight was significantly higher in the groups with SY supplementation only. On the contrary the egg shell ratio was significantly lower in the groups with SY supplementation in both amounts. The width of egg was significantly increased in the groups with selenium supplementation in both forms. The value of egg shell strength was significantly decreased in group with SY in the highest amount 0.9 mg/kg DM The average egg shell thickness was the highest in the experimental group with Se-yeast in amount 0.9 mg/kg DM, however different was not significant compared with control group. The results showed that the most of selected parameters of egg quality appeared to be significantly influenced by selenium supplementation into laying hen’s basal diet.

  18. Preparation of SnSe thin films by encapsulated selenization; Saput tipis SnSe disediakan dengan kaedah penselenidan tertudung-tebat

    Energy Technology Data Exchange (ETDEWEB)

    Sabar, D Hutagalung [Universitas Sumatera Utara, Medan (Indonesia). Dept. of Physics; Sakrani, Samsudi; Wahab, Yussof [Universiti Teknologi Malaysia, Skudai, Johor Bahru (Malaysia). Dept. of Physics

    1994-12-31

    Tin selenide thin films were prepared by encapsulated selenization. A stacked layer of evaporated Sn and Se films were annealed in a carbon block at temperatures 100 - 500 degree Celsius for 3 hours. X-ray analysis and SEM (Scanning electron) micrograph results showed that SnSe was initially formed at 150 degree Celsius with crystal size 30.0 nm and reached optimum formation at 200 daximum of 57.4 % yield of 5-decene. Other factors such as reaction temperatures, types of solvent and wt% of rhenium loadings influence the activity of the catalytic system.

  19. Atmospheric contamination

    International Nuclear Information System (INIS)

    Gruetter, Juerg

    1997-01-01

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  20. Synthesis and crystal structure of hydrogen selenates K(HSeO4)(H2SeO4) and Cs(HSeO4)(H2SeO4)

    International Nuclear Information System (INIS)

    Troyanov, S.I.; Morozov, I.V.; Zakharov, M.A.; Kemnitz, E.

    1999-01-01

    Hydrogen selenates of the compositions K(HSeO 4 )(H 2 SeO 4 ) and Cs(HSeO 4 )(H 2 SeO 4 ) are synthesized by the reaction of alkali metal carbonates with an excess of the concentrated selenic acid. The X-ray diffraction study showed that both compounds are isostructural to the corresponding hydrogen sulfates. The difference in the systems of hydrogen bonding are caused by various combinations of the acceptor functions of the oxygen atoms in the HSeO 4 and H 2 SeO 4 groups

  1. Incorporation of sulfate or selenate groups into oxotellurates(IV). I. Calcium, cadmium, and strontium compounds

    International Nuclear Information System (INIS)

    Weil, Matthias; Shirkhanlou, Mahdi

    2017-01-01

    Seven new mixed oxochalcogenate compounds in the systems M II /X VI /Te IV /O/(H), (M II = Ca, Cd, Sr; X VI = S, Se) were obtained under hydrothermal conditions (210 C, one week). Crystal structure determinations based on single-crystal X-ray diffraction data revealed the compositions Ca 3 (SeO 4 )(TeO 3 ) 2 , Ca 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (H 2 O)(SO 4 )(Te 3 O 8 ), Cd 4 (SO 4 )(TeO 3 ) 3 , Cd 5 (SO 4 ) 2 (TeO 3 ) 2 (OH) 2 , and Sr 3 (H 2 O) 2 (SeO 4 )(TeO 3 ) 2 for these phases. Peculiar features of the crystal structures of Ca 3 (SeO 4 )(TeO 3 ) 2 , Ca 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (H 2 O)(SO 4 )(Te 3 O 8 ), and Sr 3 (H 2 O) 2 (SeO 4 )(TeO 3 ) 2 are metal-oxotellurate(IV) layers connected by bridging XO 4 tetrahedra and/or by hydrogen-bonding interactions involving hydroxyl or water groups, whereas Cd 4 (SO 4 )(TeO 3 ) 3 and Cd 5 (SO 4 ) 2 (TeO 3 ) 2 (OH) 2 crystallize as framework structures. Common to all crystal structures is the stereoactivity of the Te IV electron lone pair for each oxotellurate(IV) unit, pointing either into the inter-layer space, or into channels and cavities in the crystal structures. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Selenization of mixed metal oxides for dense and ZnSe-free Cu{sub 2}ZnSnSe{sub 4} absorber films

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yitao; Chen, Guilin; Pan, Bin; Li, JianMin; Jiang, Guoshun; Liu, Weifeng, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

    2014-04-05

    Highlights: • ZnSe-free CZTSe films with large grains was prepared from mixed oxides nanopraticles. • Appearance of Zn{sub 2}SnO{sub 4} in mixed oxides precursors leads to the absence of ZnSe secondary phrase. • To obtain pure CZTSe phase, different treating temperature was used. -- Abstract: Cu{sub 2}ZnSnSe{sub 4} (CZTSe) films were prepared by direct selenization of Cu{sub 2}O, SnO{sub 2} and Zn{sub 2}SnO{sub 4} precursors. Oxides precursors were prepared by baking hydroxides precipitation. In order to obtain ZnSe-free CZTSe films, Zn{sub 2}SnO{sub 4} was used to replace separated ZnO and SnO{sub 2} as one of the precursors. Through X-ray diffraction (XRD), scanning electron microscopy (SEM), it was found that CZTSe films, with micron-sized dense grains, were obtained in our work. From Raman spectra, it was also found that the ZnSe secondary phase was absent after the selenization. An energy bandgap about 0.86 eV was obtained in our work, which confirmed the Stannite-CZTSe structure.

  3. Incorporation of sulfate or selenate groups into oxotellurates(IV). I. Calcium, cadmium, and strontium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Weil, Matthias; Shirkhanlou, Mahdi [Institute for Chemical Technologies and Analytics, Division Structural Chemistry, TU Wien, Vienna (Austria)

    2017-02-15

    Seven new mixed oxochalcogenate compounds in the systems M{sup II}/X{sup VI}/Te{sup IV}/O/(H), (M{sup II} = Ca, Cd, Sr; X{sup VI} = S, Se) were obtained under hydrothermal conditions (210 C, one week). Crystal structure determinations based on single-crystal X-ray diffraction data revealed the compositions Ca{sub 3}(SeO{sub 4})(TeO{sub 3}){sub 2}, Ca{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(H{sub 2}O)(SO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 4}(SO{sub 4})(TeO{sub 3}){sub 3}, Cd{sub 5}(SO{sub 4}){sub 2}(TeO{sub 3}){sub 2}(OH){sub 2}, and Sr{sub 3}(H{sub 2}O){sub 2}(SeO{sub 4})(TeO{sub 3}){sub 2} for these phases. Peculiar features of the crystal structures of Ca{sub 3}(SeO{sub 4})(TeO{sub 3}){sub 2}, Ca{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(H{sub 2}O)(SO{sub 4})(Te{sub 3}O{sub 8}), and Sr{sub 3}(H{sub 2}O){sub 2}(SeO{sub 4})(TeO{sub 3}){sub 2} are metal-oxotellurate(IV) layers connected by bridging XO{sub 4} tetrahedra and/or by hydrogen-bonding interactions involving hydroxyl or water groups, whereas Cd{sub 4}(SO{sub 4})(TeO{sub 3}){sub 3} and Cd{sub 5}(SO{sub 4}){sub 2}(TeO{sub 3}){sub 2}(OH){sub 2} crystallize as framework structures. Common to all crystal structures is the stereoactivity of the Te{sup IV} electron lone pair for each oxotellurate(IV) unit, pointing either into the inter-layer space, or into channels and cavities in the crystal structures. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Studies on structural, optical, and photoelectric properties of CdS{sub 1-x}Se{sub x} films fabricated by selenization of chemical bath deposited CdS films

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tianyu; Gu, Han; Ge, Zhenhua; Zhang, Lei; Wang, Zhicheng; Fang, Yong; Han, Zhida; Qian, Bin; Jiang, Xuefan [Department of Physics, Changshu Institute of Technology, Changshu (China); Wu, Wangping [School of Mechanical Engineering, Changzhou University, Changzhou (China)

    2017-02-15

    In this paper, high-photosensitive CdS{sub 1-x}Se{sub x} films are synthesized by a two-step technique, which includes the chemical bath deposition of CdS films and a following selenization process. The structural, optical, and photoelectric properties of the CdS{sub 1-x}Se{sub x} films were investigated. With the substitution of selenium for sulfur atoms, grain sizes of the as-prepared CdS{sub 1-x}Se{sub x} films are effectively enlarged and reach the scales of the films thickness when the selenization temperature exceeds 450 C. With increasing the selenization temperature from 350 to 550 C, the band gaps of CdS{sub 1-x}Se{sub x} films gradually decrease from 2.37 to 1.82 eV. Under the co-action of the grain-size enlargement and band-gap decrease, the CdS{sub 1-x}Se{sub x} films fabricated at 450 C show very pronounced photosensitivity. Noteworthy, the ratio of photo to dark conductivity of the CdS{sub 1-x}Se{sub x} film selenized at 450 C reaches 1.1 x 10{sup 5}, suggesting a promising application potential in the photoelectric devices. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Controlled formation of MoSe{sub 2} by MoN{sub x} thin film as a diffusion barrier against Se during selenization annealing for CIGS solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Chan-Wook [School of Chemical Engineering, Yeungnam University, Gyeongsangbuk-do 712-749 (Korea, Republic of); Cheon, Taehoon [School of Materials Science and Engineering, Yeungnam University, Gyeongsangbuk-do 712-749 (Korea, Republic of); Center for Core Research Facilities, DaeguGyeongbuk Institute of Science & Technology, Daegu (Korea, Republic of); Kim, Hangil [School of Materials Science and Engineering, Yeungnam University, Gyeongsangbuk-do 712-749 (Korea, Republic of); Kwon, Min-Su [School of Chemical Engineering, Yeungnam University, Gyeongsangbuk-do 712-749 (Korea, Republic of); Kim, Soo-Hyun [School of Materials Science and Engineering, Yeungnam University, Gyeongsangbuk-do 712-749 (Korea, Republic of)

    2015-09-25

    Highlights: • Mo/MoN{sub x}/Mo multilayer was investigated as a back contact for CIGS solar cell. • The MoN{sub x} protected the underlying Mo layer during high temperature selenization. • The formation of MoSe{sub 2} layer was precisely controlled. • The diffusion barrier performance of MoN{sub x} against Se was evaluated using TEM analysis. - Abstract: This study investigated the interfacial reactions and electrical properties of a Mo single layer and Mo/MoN{sub x}/Mo multilayer during high temperature selenization annealing. The Mo single layer was converted easily to MoSe{sub 2}, which was 7 times thicker than the Mo layer consumed ∼900 nm, by selenization at 460 °C for 10 min and the sheet resistance increased 8 fold compared to that of the as-deposited Mo film. On the other hand, in the Mo/MoN{sub x}/Mo structure, transmission electron microscopy (TEM) showed that the MoSe{sub 2} transformation was localized only in the top Mo layer and the bottom Mo layer was completely unaffected, even after selenization at 560 °C. The sheet resistance of the multilayer was relatively unchanged by selenization. This suggests that the MoN{sub x} layer performed well as a diffusion barrier against Se and the thickness of MoSe{sub 2} can be controlled precisely by adjusting the top Mo layer thickness. Furthermore, TEM and energy dispersive spectroscopy analysis showed that the selenized multilayer consisted of MoSe{sub 2}/Mo/MoN{sub x}/Mo, in which the top Mo layer of 60 nm was not fully converted to MoSe{sub 2} and 20 nm was left unreacted. The residual Mo interlayer located at the interface of MoSe{sub 2} and MoN{sub x} is believed to be beneficial for the ohmic contact of the selenized multilayer.

  6. Syntheses, structures, and IR spectroscopic characterization of new uranyl sulfate/selenate 1D-chain, 2D-sheet and 3D-framework

    Energy Technology Data Exchange (ETDEWEB)

    Ling Jie; Sigmon, Ginger E.; Ward, Matthew; Roback, Nancy; Burns, Peter C. [Dept. of Civil Engineering and Geological Science, Univ. of Notre Dame, IN (United States)

    2010-07-01

    Three uranyl sulfates, (C{sub 6}H{sub 20}N{sub 4})[(UO{sub 2}){sub 2} . (SO{sub 4}){sub 4}(H{sub 2}O){sub 2}](H{sub 2}O){sub 6} (TETAUS), (C{sub 15}H{sub 14}N{sub 3})[(UO{sub 2}) . (SO{sub 4}){sub 2}](NO{sub 3})(H{sub 2}O){sub 2} (TPUS), and K{sub 2}[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)] . H{sub 2}O (KUS), and two uranyl selenates, K(H{sub 3}O)[(UO{sub 2}){sub 2} . (SeO{sub 4}){sub 3}(H{sub 2}O)](H{sub 2}O){sub 6} (KUSe) and (H{sub 3}O){sub 2}[(UO{sub 2}){sub 2}(SeO{sub 4}){sub 3} . (H{sub 2}O)] (USe), were synthesized by slow evaporation of aqueous solutions at room temperature. TETAUS crystallizes in space group P anti 1, a = 6.7186(5) A, b = 9.2625(7) A, c = 13.1078(9) A, {alpha} = 72.337(2) , {beta} = 89.198(2) , {gamma} = 70.037(1) , V = 726.89(9) A{sup 3}, Z = 1. TPUS is triclinic, P anti 1, a = 6.9732(7) A, b = 13.569(1) A, c = 13.641(1) A, {alpha} = 111.809(2) , {beta} = 102.386(2) , {gamma} = 93.833(2) , V = 1150.0(2) A{sup 3}, Z = 2. KUS is orthorhombic, Cmca, a = 12.171(2) A, b = 16.689(3) A, c = 10.997(2) A, V = 2233.8(6) A{sup 3}, Z = 8. These uranyl sulfates are built from infinite one-dimensional uranyl sulfate chains with different topologies. KUSe is monoclinic, P2{sub 1}/n, a = 14.715(1) A, b = 10.1557(7) A, c = 15.833(1) A, {beta} = 114.415(1) , V = 2154.5(3) A{sup 3}, Z = 4. Its structure is based on a two-dimensional uranyl selenate sheet. USe crystallizes in space group P2{sub 1}/c, a = 10.6124(2) A, b = 14.7717(3) A, c = 13.7139(3) A, {beta} = 96.989(1) , V = 2133.86(8) A{sup 3}, Z = 4, with a complex three-dimensional uranyl selenate framework containing channels extending in three directions. (orig.)

  7. Structure of caesium selenate

    International Nuclear Information System (INIS)

    Zuniga, F.J.; Breczewski, T.; Arnaiz, A.

    1991-01-01

    Cs 2 SeO 4 , M 4 =408.77, orthorhombic, Pnam, a=8.3777 (8), b=11.276 (2), c=6.434 (2) A, V=607.8 (2) A 3 , Z=4, D x =4.46 Mg m -3 , MoKα, λ=0.71069 A, μ=185.06 cm -1 , F(000)=704, T=293 K, R=0.048, 3348 observed reflections. Average values of the Se-O and Cs-O distances are 1.637 (4) and 3.387 (3) A, respectively [range 3.038 (5)-3.872 (6) A with 9 and 11 coordination of caesium by oxygen]. (orig.)

  8. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  9. Chiral speciation and determination of selenomethionine enantiomers in selenized yeast by ligand-exchange micellar electrokinetic capillary chromatography after solid phase extraction.

    Science.gov (United States)

    Duan, Jiankun; He, Man; Hu, Bin

    2012-12-14

    A new phenylalanine derivative (L-N-(2-hydroxy-propyl)-phenylalanine, L-HP-Phe) was synthesized and its chelate with Cu(II) (Cu(II)-(L-HP-Phe)(2)) was used as the chiral selector for the ligand-exchange (LE) chiral separation of D,L-selenomethionine (SeMet) in selenized yeast samples by micelle electrokinetic capillary chromatography (MEKC). In order to improve the sensitivity of MEKC-UV, two-step preconcentration strategy was employed, off-line solid phase extraction (SPE) and on-line large volume sample stacking (LVSS). D,L-SeMet was first retained on the Cu(II) loaded mesoporous TiO(2), then eluted by 0.1 mL of 5 mol L(-1) ammonia, and finally introduced for MEKC-UV analysis by LVSS injection after evaporation of NH(3). With the enrichment factors of 1400 and 1378, the LODs of 0.44 and 0.60 ng mL(-1) for L-SeMet and D-SeMet was obtained, respectively. The developed method was applied to the analysis of D,L-SeMet in a certified reference material of SELM-1 and a commercial nutrition yeast, and the results showed that most of SeMet in the SELM-1 selenized yeast was l isomer and the recovery for L and D isomers in the spiked commercial nutrition yeast was 96.3% and 103%, respectively. This method is featured with low running cost, high sensitivity and selectivity, and exhibits application potential in chiral analysis of seleno amino acids in real world samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...

  11. Atmospheric electrodynamics

    International Nuclear Information System (INIS)

    Volland, H.

    1984-01-01

    The book Atmospheric Electrodynamics, by Hans Voland is reviewed. The book describes a wide variety of electrical phenomena occurring in the upper and lower atmosphere and develops the mathematical models which simulate these processes. The reviewer finds that the book is of interest to researchers with a background in electromagnetic theory but is of only limited use as a reference work

  12. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

    What is an urban atmosphere? How can we differentiate an 'atmosphere' from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an 'affective atmosphere' as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres.

  13. Atmospheric Electricity

    Science.gov (United States)

    Aplin, Karen; Fischer, Georg

    2018-02-01

    Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and electric fields. On Earth, lightning is likely to have existed for a long time, based on evidence from fossilized lightning strikes in ancient rocks, but observations of planetary lightning are necessarily much more recent. The generation and observations of lightning and other atmospheric electrical processes, both from within-atmosphere measurements, and spacecraft remote sensing, can be readily studied using a comparative planetology approach, with Earth as a model. All atmospheres contain charged molecules, electrons, and/or molecular clusters created by ionization from cosmic rays and other processes, which may affect an atmosphere's energy balance both through aerosol and cloud formation, and direct absorption of radiation. Several planets are anticipated to host a "global electric circuit" by analogy with the circuit occurring on Earth, where thunderstorms drive current of ions or electrons through weakly conductive parts of the atmosphere. This current flow may further modulate an atmosphere's radiative properties through cloud and aerosol effects. Lightning could potentially have implications for life through its effects on atmospheric chemistry and particle transport. It has been observed on many of the Solar System planets (Earth, Jupiter, Saturn, Uranus, and Neptune) and it may also be present on Venus and Mars. On Earth, Jupiter, and Saturn, lightning is thought to be generated in deep water and ice clouds, but discharges can be generated in dust, as for terrestrial volcanic lightning, and on Mars. Other, less well-understood mechanisms causing discharges in non-water clouds also seem likely. The discovery of thousands of exoplanets has recently led to a range of further exotic possibilities for atmospheric electricity, though lightning detection beyond our Solar System

  14. Photochemistry of Planetary Atmospheres

    Science.gov (United States)

    Yung, Y. L.

    2005-12-01

    The Space Age started half a century ago. Today, with the completion of a fairly detailed study of the planets of the Solar System, we have begun studying exoplanets (or extrasolar planets). The overriding question in is to ask whether an exoplanet is habitable and harbors life, and if so, what the biosignatures ought to be. This forces us to confront the fundamental question of what controls the composition of an atmosphere. The composition of a planetary atmosphere reflects a balance between thermodynamic equilibrium chemistry (as in the interior of giant planets) and photochemistry (as in the atmosphere of Mars). The terrestrial atmosphere has additional influence from life (biochemistry). The bulk of photochemistry in planetary atmospheres is driven by UV radiation. Photosynthesis may be considered an extension of photochemistry by inventing a molecule (chlorophyll) that can harvest visible light. Perhaps the most remarkable feature of photochemistry is catalytic chemistry, the ability of trace amounts of gases to profoundly affect the composition of the atmosphere. Notable examples include HOx (H, OH and HO2) chemistry on Mars and chlorine chemistry on Earth and Venus. Another remarkable feature of photochemistry is organic synthesis in the outer solar system. The best example is the atmosphere of Titan. Photolysis of methane results in the synthesis of more complex hydrocarbons. The hydrocarbon chemistry inevitably leads to the formation of high molecular weight products, giving rise to aerosols when the ambient atmosphere is cool enough for them to condense. These results are supported by the findings of the recent Cassini mission. Lastly, photochemistry leaves a distinctive isotopic signature that can be used to trace back the evolutionary history of the atmosphere. Examples include nitrogen isotopes on Mars and sulfur isotopes on Earth. Returning to the question of biosignatures on an exoplanet, our Solar System experience tells us to look for speciation

  15. Mars: Atmosphere

    Science.gov (United States)

    Moroz, V.; Murdin, P.

    2001-07-01

    The atmosphere of MARS is much thinner than the terrestrial one. However, even the simplest visual telescopic observations show a set of atmospheric events such as seasonal exchange of material between polar caps, temporal appearance of clouds and changes of visibility of dark regions on the disk of the planet. In 1947 the prominent CO2 bands in the near-infrared part of the Martian spectrum were...

  16. Preparation and Characterization of Cu(In,GaSe2 Thin Films by Selenization of Cu0.8Ga0.2 and In2Se3 Precursor Films

    Directory of Open Access Journals (Sweden)

    Jiang Liu

    2012-01-01

    Full Text Available Se-containing precursor films with two different compositions were prepared by magnetron sputtering from and targets, and then were selenized using Se vapor. The effects of precursor composition and selenization temperature on the film properties were investigated. The results show that Se phase plays a critical role in film growth and electrical properties of CIGS films. The Cu-rich films exhibit different surface morphology and better crystallinity, as compared to the Cu-poor films. All the CIGS films exhibit p-type conductivity. The resistivity of the Cu-rich films is about three orders of magnitude lower than that of the Cu-poor films, which is attributed to the presence of p-type highly conductive Se phase.

  17. Synthesis and crystal structure of a new neodymium(III) selenate-selenite: Nd2(SeO4)(SeO3)2(H2O)2

    International Nuclear Information System (INIS)

    Feng Meiling; Mao Jianggao

    2005-01-01

    The title new neodymium(III) selenate-selenite was obtained by hydrothermal reactions of neodymium(III) oxide, H 2 SeO 4 and 1,10-phenanthroline at 140 o C. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group C2/c with cell parameters of a = 12.258(2) A, b 7.1024(15) A, c = 13.391(3) A, β = 104.250(2) o . The structure of Nd 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 is isomorphous with that of Er 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 , which was refined in the monoclinic space group C2 with the disordered selenate group. It features an ordered 3D network with channels along b-axis. The selenate or selenite groups alone can form a 2D layer with the Nd(III) ions. IR spectrum, TGA and luminescent studies have also been performed

  18. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  19. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  20. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  1. Comparing the influence of selenite (Se4+) and selenate (Se6+) on the inhibition of the mercury (Hg) phytotoxicity to pak choi.

    Science.gov (United States)

    Tran, Thi Anh Thu; Dinh, Quang Toan; Cui, Zeiwei; Huang, Jie; Wang, Dan; Wei, Tianjiao; Liang, Dongli; Sun, Xin; Ning, Ping

    2018-01-01

    Selenite (Se (IV)) and selenate (Se (IV)) have recently been demonstrated to be equally effective in inhibiting mercury (Hg) phytotoxicity to plants. This assertion is still unclear. In this study, we aimed to explore the potential effects of Se species (Se 4+ and Se 6+ ) on the inhibition of the mercury (Hg) bioavailability to pak choi in dry land. Pot experiments with exposure to different dosages of mercuric chloride (HgCl 2 ) and selenite (Na 2 SeO 3 ) or selenate (Na 2 SeO 4 ) were treated. To compare the influence of Se (IV) and Se (VI) on the bioaccumulation and bioavailability of Hg, the levels of total Hg in different pak choi (Brassica chinensis L.) tissues (roots and shoots) and the distribution changes of Hg fractions in soil before planting and after harvest were determined as well as the Hg I R values in soils (relative binding intensity) were analyzed. Results showed that application Se (IV) reduced the concentrations of Hg in pak choi roots more than Se (VI). Hg concentrations were also decreased in pak choi shoots in Se (IV) treatments, while which notably increased in Se (VI) treatments. Thus, Se (IV) plays a more important role than Se (VI) in limiting the absorption and bioaccumulation of Hg in pak choi. Moreover, this inhibition may only significantly occur when Se (IV) is at an appropriate level (2.5mg/kg). In addition, the good correlations between the proportions of mobile Hg fractions (soluble and exchangeable fractions), I R values with the Hg concentrations in plants were observed. This affirmed the importance of the Hg fractions transformation and the I R indicator of Hg in the assessment of their bioavailability. Our findings regarding the importance of Se (IV) influence in reducing Hg bioaccumulation not only provided the correct appraisal about the effect of Se species on the inhibition of the Hg phytotoxicity to pak choi in dry land, but also be a good reference for selecting Se fertilizer forms (Se 4+ or Se 6+ ). Copyright © 2017

  2. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    Nurses working in the Neuro-Intensive Care Unit at Aarhus University Hospital lack the tools to prepare children for the alarming atmosphere they will enter when visiting a hospitalised relative. The complex soundscape dominated by alarms and sounds from equipment is mentioned as the main stressor...

  3. Puerto Rico Revealed Preference Survey Data 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Revealed preference models provide insights into recreational angler behavior and the economic value of recreational fishing trips. Revealed preference data is...

  4. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  5. Selenization of Cu2ZnSnS4 Enhanced the Performance of Dye-Sensitized Solar Cells: Improved Zinc-Site Catalytic Activity for I3.

    Science.gov (United States)

    Wang, Xiuwen; Xie, Ying; Bateer, Buhe; Pan, Kai; Jiao, Yanqing; Xiong, Ni; Wang, Song; Fu, Honggang

    2017-11-01

    Cu 2 ZnSnS 4 (CZTS) and Cu 2 ZnSn(S,Se) 4 (CZTSSe) as promising photovoltaic materials have drawn much attention because they are environmentally benign and earth-abundant elements. In this work, the monodispersed, low-cost Cu 2 ZnSnS 4 nanocrystals with small size have been controllably synthesized via a wet chemical routine. And CZTSSe could be easily prepared after selenization of CZTS. When they are employed as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), the power conversion efficiency (PCE) has been improved from 3.54% to 7.13% as CZTS is converted to CZTSSe, which is also compared to that of Pt (7.62%). The exact reason for the enhanced catalytic activity of I 3 - is discussed with the work function and density functional theory (DFT) when CZTSSe converted from CZTS. The results of a Kelvin probe suggest that the work function of CZTSSe (5.61 eV) is closer to that of Pt (5.65 eV) and higher than that of CZTS, which matched the redox shuttle potential better. According to the theory calculation, all the atomic and bond populations changed significantly when Se replaced partly the S on the CZTS system, especially in the Zn site. During the catalytic process as CEs, the adsorption energy obviously increased compared to those at other sites when I 3 - adsorbed on the Zn site in CZTSSe. So, Zn plays an important role for the reduction of I 3 - after CZTS is converted to CZTSSe. Based on above analysis, the reason for enhanced performance of DSSCs when CZTS converted to CZTSSe is mainly due to the enhancement of Zn-site activity. This work is beneficial for understanding the catalytic reaction mechanism of CZTS(Se) as CEs of DSSCs.

  6. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium; Etude de la resistance de Cupriavidus metallidurans CH34 aux oxyanions selenite et seleniate: accumulation, localisation et transformation du selenium

    Energy Technology Data Exchange (ETDEWEB)

    Avoscan, L

    2007-06-15

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  7. Mathematics revealed

    CERN Document Server

    Berman, Elizabeth

    1979-01-01

    Mathematics Revealed focuses on the principles, processes, operations, and exercises in mathematics.The book first offers information on whole numbers, fractions, and decimals and percents. Discussions focus on measuring length, percent, decimals, numbers as products, addition and subtraction of fractions, mixed numbers and ratios, division of fractions, addition, subtraction, multiplication, and division. The text then examines positive and negative numbers and powers and computation. Topics include division and averages, multiplication, ratios, and measurements, scientific notation and estim

  8. Selenizing Hericium erinaceus polysaccharides induces dendritic cells maturation through MAPK and NF-κB signaling pathways.

    Science.gov (United States)

    Qin, Tao; Ren, Zhe; Huang, Yifan; Song, Yulong; Lin, Dandan; Li, Jian; Ma, Yufang; Wu, Xiuqin; Qiu, Fuan; Xiao, Qi

    2017-04-01

    In this study, polysaccharides extracted from Hericium erinaceus were modified to obtain its nine selenium derivatives, sHEP 1 -sHEP 9 . Their structures were identified, yields and selenium contents were determined, the phenotypic and functional maturation of murine bone marrow-derived dendritic cells (DCs) and relevant mechanisms were compared taking unmodified HEP as control. The results revealed that the selenylation were successful. sHEP 1 , sHEP 2 and sHEP 8 treatment of DCs increased their surface expression of MHC-II and CD86 and indicated that sHEP 1 , sHEP 2 and sHEP 8 induced DC maturation. Furthermore, sHEP 2 and sHEP 8 also significantly decreased DCs endocytosis and significantly enhanced cytokine (IL-12 and IFN-γ) production. In line with TLR4 activation, sHEP 2 increased the phosphorylation of ERK, p38, and JNK, and the nuclear translocation of p-c-Jun, p-CREB, and c-Fos. sHEP 2 also activated NF-κB signaling, as evidenced by degradation of IκBα/β and nuclear translocation of p65 and p50. Together, these results suggest that sHEP is a strong immunostimulant. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Atmospheric chemistry and climate

    OpenAIRE

    Satheesh, SK

    2012-01-01

    Atmospheric chemistry is a branch of atmospheric science where major focus is the composition of the Earth's atmosphere. Knowledge of atmospheric composition is essential due to its interaction with (solar and terrestrial) radiation and interactions of atmospheric species (gaseous and particulate matter) with living organisms. Since atmospheric chemistry covers a vast range of topics, in this article the focus is on the chemistry of atmospheric aerosols with special emphasis on the Indian reg...

  10. Revealing Rembrandt

    Directory of Open Access Journals (Sweden)

    Andrew J Parker

    2014-04-01

    Full Text Available The power and significance of artwork in shaping human cognition is self-evident. The starting point for our empirical investigations is the view that the task of neuroscience is to integrate itself with other forms of knowledge, rather than to seek to supplant them. In our recent work, we examined a particular aspect of the appreciation of artwork using present-day functional magnetic resonance imaging (fMRI. Our results emphasised the continuity between viewing artwork and other human cognitive activities. We also showed that appreciation of a particular aspect of artwork, namely authenticity, depends upon the co-ordinated activity between the brain regions involved in multiple decision making and those responsible for processing visual information. The findings about brain function probably have no specific consequences for understanding how people respond to the art of Rembrandt in comparison with their response to other artworks. However, the use of images of Rembrandt’s portraits, his most intimate and personal works, clearly had a significant impact upon our viewers, even though they have been spatially confined to the interior of an MRI scanner at the time of viewing. Neuroscientific studies of humans viewing artwork have the capacity to reveal the diversity of human cognitive responses that may be induced by external advice or context as people view artwork in a variety of frameworks and settings.

  11. Atmospheric chemistry of peroxynitrates

    International Nuclear Information System (INIS)

    Hendry, D.G.; Kenley, R.A.

    1979-01-01

    The thermochemistry and kinetics of the various types of peroxy nitrates are discussed, and the influence of these compounds on smog formation is evaluated. The heats of formation and of two dissociation reactions for various peroxyalkyl nitrates are calculated and it is shown that dissociation into nitrogen dioxide is more favorable than into nitrogen trioxide for the peroxyalkyl and peroxyacetyl nitrates (PANs). The atmospheric lifetimes of peroxynitric acid, peroxyalkyl nitrates and peroxyacyl nitrates are estimated as a function of temperature and it is found that PANs can exhibit lifetimes greater than a day at low temperatures, resulting in significant concentrations. In the presence of NO, PANs are shown to be an important source of OH radicals in the early morning and at night. A computer simulation reveals the contribution of PANs to ozone formation by the oxidation of NO to NO2

  12. Sorption mechanisms of selenium species (selenite and selenate) on copper-based minerals; Mecanismes de sorption des especes du selenium (selenite et seleniate) sur des mineraux a base de cuivre

    Energy Technology Data Exchange (ETDEWEB)

    Devoy, J

    2001-09-01

    The sorption of radionuclides on the surface of minerals represents a process capable to delay the migration of the elements from a spent fuel deep repository towards the biosphere. In the framework of a deep underground repository, an engineered clay barrier has a high trapping capacity for cationic radio-elements, in particular because of the negative charge of clay surfaces. However, anionic radioelements like selenium species, would be only weakly retained by chemical processes. In order to optimize the trapping capacity of a clay barrier with respect to anionic species, prospective studies are carried out in order to find and evaluate some minerals with specific chemical trapping functions. Among radionuclides, the case of selenium has to be considered because its isotope {sup 79}Se is present in radioactive wastes and has a half life time of 6.5 10{sup 4} years. It is also judicious to find a mineral capable of trapping simultaneously several anionic radio-elements. Copper oxides and sulfides (Cu{sub 2}O, CuO, Cu{sub 2}S, CuS, CuFeS{sub 2} and Cu{sub 5}FeS{sub 4}) are good adsorbents with respect to selenium species (selenite and selenate). These minerals, with their selenium retention properties, could be used also for the decontamination of soils and waters or to process industrial effluents. The sorption mechanisms have been studied in details for copper oxides (Cu{sub 2}O and CuO) with respect to selenite and selenate. Chalcomenite precipitates in acid pH conditions when selenite is added to a Cu{sub 2}O and CuO suspension. Selenate, in contact with cuprite (Cu{sub 2}O) leads also to a selenium-based precipitate in acid pH environment. For higher pH values, selenite and selenate are adsorbed on copper oxides (Cu{sub 2}O and CuO) and lead to internal and external sphere complexes, respectively. In the case of a selenite/cuprite mixture in basic pH environment and at the equilibrium, a chemical reaction occurs between the oxidation product of cuprite, Cu

  13. Titan Casts Revealing Shadow

    Science.gov (United States)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  14. Our shared atmosphere

    Science.gov (United States)

    Our atmosphere is a precious and fascinating resource, providing air to breath, shielding us from harmful ultraviolet radiation (UV), and maintaining a comfortable climate. Since the industrial revolution, people have significantly altered the composition of the atmosphere throu...

  15. Atmospheric refraction : a history

    NARCIS (Netherlands)

    Lehn, WH; van der Werf, S

    2005-01-01

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of

  16. Mobile Instruments Measure Atmospheric Pollutants

    Science.gov (United States)

    2009-01-01

    As a part of NASA's active research of the Earth s atmosphere, which has included missions such as the Atmospheric Laboratory of Applications and Science (ATLAS, launched in 1992) and the Total Ozone Mapping Spectrometer (TOMS, launched on the Earth Probe satellite in 1996), the Agency also performs ground-based air pollution research. The ability to measure trace amounts of airborne pollutants precisely and quickly is important for determining natural patterns and human effects on global warming and air pollution, but until recent advances in field-grade spectroscopic instrumentation, this rapid, accurate data collection was limited and extremely difficult. In order to understand causes of climate change and airborne pollution, NASA has supported the development of compact, low power, rapid response instruments operating in the mid-infrared "molecular fingerprint" portion of the electromagnetic spectrum. These instruments, which measure atmospheric trace gases and airborne particles, can be deployed in mobile laboratories - customized ground vehicles, typically - to map distributions of pollutants in real time. The instruments must be rugged enough to operate rapidly and accurately, despite frequent jostling that can misalign, damage, or disconnect sensitive components. By measuring quickly while moving through an environment, a mobile laboratory can correlate data and geographic points, revealing patterns in the environment s pollutants. Rapid pollutant measurements also enable direct determination of pollutant sources and sinks (mechanisms that remove greenhouse gases and pollutants), providing information critical to understanding and managing atmospheric greenhouse gas and air pollutant concentrations.

  17. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Yates, Jack S.; Palmer, Paul I. [School of GeoSciences, University of Edinburgh (United Kingdom); Biller, Beth; Cockell, Charles S., E-mail: j.s.yates@ed.ac.uk [Centre for Exoplanet Science, University of Edinburgh (United Kingdom)

    2017-02-20

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. To illustrate our model, we use a cool Y dwarf atmosphere, such as WISE J085510.83–0714442.5, whose 4.5–5.2 μ m spectrum shows absorption features consistent with water vapor and clouds. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment, we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Based on a previously defined statistical approach, we infer that there are of the order of 10{sup 9} cool Y brown dwarfs in the Milky Way, and likely a few tens of these objects are within 10 pc from Earth. Our work also has implications for exploring life in the atmospheres of temperate gas giants. Consideration of the habitable volumes in planetary atmospheres significantly increases the volume of habitable space in the galaxy.

  18. The atmospheric extinction of light

    International Nuclear Information System (INIS)

    Hughes, Stephen W; Powell, Sean; Carroll, Joshua; Cowley, Michael

    2016-01-01

    An experiment is described that enables students to understand the properties of atmospheric extinction due to Rayleigh scattering. The experiment requires the use of red, green and blue lasers attached to a travelling microscope or similar device. The laser beams are passed through an artificial atmosphere, made from milky water, at varying depths, before impinging on either a light meter or a photodiode integral to a Picotech Dr. DAQ ADC. A plot of measured spectral intensity verses depth reveals the contribution Rayleigh scattering has to the extinction coefficient. For the experiment with the light meter, the extinction coefficients for red, green and blue light in the milky sample of water were 0.27, 0.36 and 0.47 cm −1 respectively and 0.032, 0.037 and 0.092 cm −1 for the Picotech Dr. DAQ ADC. (paper)

  19. Pluto's surface composition and atmosphere

    Science.gov (United States)

    Young, L. A.; Gladstone, R.; Summers, M. E.; Strobel, D. F.; Kammer, J.; Hinson, D. P.; Grundy, W. M.; Cruikshank, D. P.; Protopapa, S.; Schmitt, B.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.

    2017-12-01

    New Horizons studied Pluto's N2-dominated neutral atmosphere through radio (at 4.2 cm with the REX radio experiment), solar and stellar occultations and airglow (at 52-187 nm with the Alice ultraviolet spectrograph), and imaging (with the LORRI and MVIC visible-wavelength cameras). It studied the plasma environment and solar wind interaction with in situ instruments (PEPPSI and SWAP). Contemporaneous observations of Pluto's atmosphere from Earth included a ground-based stellar occultation and ALMA observations of gaseous CO and HCN. Joint analysis of these datasets reveal a variable boundary layer; a stable lower atmosphere; radiative heating and cooling; haze production and hydrocarbon chemistry; diffusive equilibrium; and slower-than-expected escape. New Horizons studied Pluto's surface composition with the LEISA near-infrared spectral imager from 1.25 to 2.5 micron. Additional compositional information at higher spatial resolution came from the MVIC 4-channel color imager, which included a channel centered at 0.89 micron specifically designed to detect solid CH4. These instruments allow mapping of the volatiles N2, CO, and CH4, the surface expression of the H2O bedrock, and the dark, reddish material presumed to be tholins. These observations reveal a large equatorial basin (informally named Sptunik Planitia), filled with N2 ice with minor amounts of CO and CH4, surrounded by hills of CH4 and H2O ice. Broadly speaking, composition outside of Sptunik Planitia follows latitudinal banding, with dark, mainly volatile free terrains near the equator, with N2, CO, and CH4 at mid-northern latitudes, and mainly CH4 at high northern latitudes. Deviations from these broad trends are seen, and point to complex surface-atmosphere interactions at diurnal, seasonal, perennial, and million-year timescales.

  20. Archives of Atmospheric Lead Pollution

    Science.gov (United States)

    Weiss, Dominik; Shotyk, William; Kempf, Oliver

    Environmental archives such as peat bogs, sediments, corals, trees, polar ice, plant material from herbarium collections, and human tissue material have greatly helped to assess both ancient and recent atmospheric lead deposition and its sources on a regional and global scale. In Europe detectable atmospheric lead pollution began as early as 6000years ago due to enhanced soil dust and agricultural activities, as studies of peat bogs reveal. Increased lead emissions during ancient Greek and Roman times have been recorded and identified in many long-term archives such as lake sediments in Sweden, ice cores in Greenland, and peat bogs in Spain, Switzerland, the United Kingdom, and the Netherlands. For the period since the Industrial Revolution, other archives such as corals, trees, and herbarium collections provide similar chronologies of atmospheric lead pollution, with periods of enhanced lead deposition occurring at the turn of the century and since 1950. The main sources have been industry, including coal burning, ferrous and nonferrous smelting, and open waste incineration until c.1950 and leaded gasoline use since 1950. The greatest lead emissions to the atmosphere all over Europe occurred between 1950 and 1980 due to traffic exhaust. A marked drop in atmospheric lead fluxes found in most archives since the 1980s has been attributed to the phasing out of leaded gasoline. The isotope ratios of lead in the various archives show qualitatively similar temporal changes, for example, the immediate response to the introduction and phasing out of leaded gasoline. Isotope studies largely confirm source assessments based on lead emission inventories and allow the contributions of various anthropogenic sources to be calculated.

  1. Fair weather atmospheric electricity

    International Nuclear Information System (INIS)

    Harrison, R G

    2011-01-01

    Not long after Franklin's iconic studies, an atmospheric electric field was discovered in 'fair weather' regions, well away from thunderstorms. The origin of the fair weather field was sought by Lord Kelvin, through development of electrostatic instrumentation and early data logging techniques, but was ultimately explained through the global circuit model of C.T.R. Wilson. In Wilson's model, charge exchanged by disturbed weather electrifies the ionosphere, and returns via a small vertical current density in fair weather regions. New insights into the relevance of fair weather atmospheric electricity to terrestrial and planetary atmospheres are now emerging. For example, there is a possible role of the global circuit current density in atmospheric processes, such as cloud formation. Beyond natural atmospheric processes, a novel practical application is the use of early atmospheric electrostatic investigations to provide quantitative information on past urban air pollution.

  2. Atmosphere physics and chemistry

    International Nuclear Information System (INIS)

    Delmas, R.; Megie, G.; Peuch, V.H.

    2005-10-01

    Since the 1970's, the awareness about the atmospheric pollution threat has led to a spectacular development of the researches on the complex interactions between the chemical composition of the atmosphere and the climate. This book makes a synthesis of the state-of-the-art in this very active domain of research. Content: introduction, atmosphere dynamics and transport, matter-radiation interaction and radiant transfer, physico-chemical processes, atmospheric aerosol and heterogenous chemistry, anthropic and natural emissions and deposition, stratospheric chemical system, tropospheric chemical system, polluted boundary layer, paleo-environments and ice archives, role of atmospheric chemistry in global changes, measurement principles and instruments, numerical modeling, experimental strategy, regulation and management of the atmospheric environment, index. (J.S.)

  3. Phytoremediation of Atmospheric Methane

    Science.gov (United States)

    2013-04-15

    REPORT Phytoremediation of Atmospheric Methane 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: We have transformed a plant, Arabidopsis thaliana, with the...298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - 31-Mar-2012 Phytoremediation of Atmospheric Methane Report Title ABSTRACT We have transformed a...DD882) Scientific Progress See attachment Technology Transfer 1    Final Report for DARPA project W911NF1010027  Phytoremediation  of Atmospheric

  4. Oscillations in stellar atmospheres

    International Nuclear Information System (INIS)

    Costa, A.; Ringuelet, A.E.; Fontenla, J.M.

    1989-01-01

    Atmospheric excitation and propagation of oscillations are analyzed for typical pulsating stars. The linear, plane-parallel approach for the pulsating atmosphere gives a local description of the phenomenon. From the local analysis of oscillations, the minimum frequencies are obtained for radially propagating waves. The comparison of the minimum frequencies obtained for a variety of stellar types is in good agreement with the observed periods of the oscillations. The role of the atmosphere in the globar stellar pulsations is thus emphasized. 7 refs

  5. Nucleation in the atmosphere

    International Nuclear Information System (INIS)

    Hegg, D A; Baker, M B

    2009-01-01

    Small particles play major roles in modulating radiative and hydrological fluxes in the atmosphere and thus they impact both climate (IPCC 2007) and weather. Most atmospheric particles outside clouds are created in situ through nucleation from gas phase precursors and most ice particles within clouds are formed by nucleation, usually from the liquid. Thus, the nucleation process is of great significance in the Earth's atmosphere. The theoretical examination of nucleation in the atmosphere has been based mostly on classical nucleation theory. While diagnostically very useful, the prognostic skill demonstrated by this approach has been marginal. Microscopic approaches such as molecular dynamics and density functional theory have also proven useful in elucidating various aspects of the process but are not yet sufficiently refined to offer a significant prognostic advantage to the classical approach, due primarily to the heteromolecular nature of atmospheric nucleation. An important aspect of the nucleation process in the atmosphere is that the degree of metastability of the parent phase for the nucleation is modulated by a number of atmospheric processes such as condensation onto pre-existing particles, updraft velocities that are the main driving force for supersaturation of water (a major factor in all atmospheric nucleation), and photochemical production rates of nucleation precursors. Hence, atmospheric nucleation is both temporally and spatially inhomogeneous

  6. Atmospheric Measurements Laboratory (AML)

    Data.gov (United States)

    Federal Laboratory Consortium — The Atmospheric Measurements Laboratory (AML) is one of the nation's leading research facilities for understanding aerosols, clouds, and their interactions. The AML...

  7. Simultaneous detection of selenium by atomic fluorescence and sulfur by molecular emission by flow-injection hydride generation with on-line reduction for the determination of selenate, sulfate and sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Tyson, J.F., E-mail: tyson@chem.umass.edu [Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Palmer, C.D. [Lead Poisoning Trace Elements Laboratory, Wadsworth Center, New York State Department of Health, P.O. Box 509, Empire State Plaza, Albany, NY 12201-0509 (United States)

    2009-10-12

    An inductively coupled plasma atomic fluorescence spectrometry (ICP-AFS) instrument, was modified so that it was capable of monitoring transient chromatographic or flow-injection profiles and that sulfur molecular emission and selenium atomic fluorescence could be monitored simultaneously in an argon-hydrogen diffusion flame on a glass burner. The analytes were introduced as hydrogen selenide and hydrogen sulfide, generated on a flow-injection manifold. Selenate was reduced to hydride-forming selenite by microwave-assisted on-line reaction with hydrochloric acid, and sulfate, or sulfite, was reduced to hydride-forming sulfide by a mixture of hydriodic acid, acetic acid and sodium hypophosphite. The effects of the nature of reducing agent, flow rate, microwave power and coil length were studied. The limit of detection (3 s) for selenium was 10 {mu}g L{sup -1}, and for sulfide was 70 {mu}g L{sup -1} (200-{mu}L injection volume). The calibration was linear for selenium up to 2 mg L{sup -1} and to 10 mg L{sup -1} for sulfide. The throughput was 180 h{sup -1}. The three sulfur species could be differentiated on the basis of reactivity at various microwave powers.

  8. Synthesis and crystal structure of Fe[(Te1.5Se0.5)O5]Cl, the first iron compound with selenate(IV) and tellurate(IV) groups

    Science.gov (United States)

    Akhrorov, Akhmad Yu; Kuznetsova, Elena S.; Aksenov, Sergey M.; Berdonosov, Peter S.; Kuznetsov, Alexey N.; Dolgikh, Valery A.

    2017-12-01

    During the search for selenium analogues of FeTe2O5Cl, the new iron (III) tellurate(IV) selenate(IV) chloride with the composition Fe[(Te1.5Se0.5)O5]Cl was synthesized by chemical vapor transport (CVT) reaction and characterized by TGA-, EDX-,SCXRD-analysis, as well as IR and Raman spectroscopy. It was found that Fe[(Te1.5Se0.5)O5]Cl crystallizes in the monoclinic space group P21/c with unitcell parameters a = 5.183(3) Å, b = 15.521(9) Å, c = 7.128(5) Å and β = 107.16(1)°. The crystal structure of Fe[(Te1.5Se0.5)O5]Cl represents a new structure type and contains electroneutral heteropolyhedral layers formed by dimers of the [FeO5Cl]8- octahedra, linked via common O-O edges, and mixed [Te3SeO10]4- tetramers. Adjacent layers are stacked along the b axis and linked by weak residual bonds. The new compound is stable up to 420 °C. DFT calculations predict Fe[(Te1.5Se0.5)O5]Cl to be a wide-gap semiconductor with the band gap of ca. 2.7 eV.

  9. Deuterium in atmospheric cycle

    International Nuclear Information System (INIS)

    Pontikis, M.C.

    Interest of the study concerning the deuterium content variation (HDO) in the atmospheric water. Standards and measurement methods. Molecule HDO cycle in the atmospheric water. Application to the study of hail-generating cumulus-nimbus and of the mantle of snow [fr

  10. Urban atmospheric contamination

    International Nuclear Information System (INIS)

    Baldasano Jose, M.

    1997-01-01

    The problems of contamination are not only limited to this century, pale pathology evidences of the effects of the contamination of the air exist in interiors in the health of the old ones; the article mention the elements that configure the problem of the atmospheric contamination, atmospheric pollutants and emission sources, orography condition and effects induced by the urbanization process

  11. Controlled Atmosphere Stunning

    NARCIS (Netherlands)

    Lambooij, E.; Gerritzen, M.A.

    2009-01-01

    Controlled atmosphere (CAS) stunning includes several variations of gaseous mixtures given to induce an anaesthetic state before slaughter poultry. One method of multi phase CAS is to unload the birds out of the crate on a conveyor belt and subject the birds to an atmosphere of 30% O2, 40% CO2 and

  12. Atmosphere Impact Losses

    Science.gov (United States)

    Schlichting, Hilke E.; Mukhopadhyay, Sujoy

    2018-02-01

    Determining the origin of volatiles on terrestrial planets and quantifying atmospheric loss during planet formation is crucial for understanding the history and evolution of planetary atmospheres. Using geochemical observations of noble gases and major volatiles we determine what the present day inventory of volatiles tells us about the sources, the accretion process and the early differentiation of the Earth. We further quantify the key volatile loss mechanisms and the atmospheric loss history during Earth's formation. Volatiles were accreted throughout the Earth's formation, but Earth's early accretion history was volatile poor. Although nebular Ne and possible H in the deep mantle might be a fingerprint of this early accretion, most of the mantle does not remember this signature implying that volatile loss occurred during accretion. Present day geochemistry of volatiles shows no evidence of hydrodynamic escape as the isotopic compositions of most volatiles are chondritic. This suggests that atmospheric loss generated by impacts played a major role during Earth's formation. While many of the volatiles have chondritic isotopic ratios, their relative abundances are certainly not chondritic again suggesting volatile loss tied to impacts. Geochemical evidence of atmospheric loss comes from the {}3He/{}^{22}Ne, halogen ratios (e.g., F/Cl) and low H/N ratios. In addition, the geochemical ratios indicate that most of the water could have been delivered prior to the Moon forming impact and that the Moon forming impact did not drive off the ocean. Given the importance of impacts in determining the volatile budget of the Earth we examine the contributions to atmospheric loss from both small and large impacts. We find that atmospheric mass loss due to impacts can be characterized into three different regimes: 1) Giant Impacts, that create a strong shock transversing the whole planet and that can lead to atmospheric loss globally. 2) Large enough impactors (m_{cap} ≳ √{2

  13. Atmospheric signals produced by cavity rebound

    International Nuclear Information System (INIS)

    Jones, E.M.; App, F.N.; Whitaker, R.W.

    1993-01-01

    An analysis of the atmospheric acoustic signals produced by a class of low-yield tests conducted just below the base of the alluvial cover in Yucca Flat of the Nevada Test Site (NTS), has revealed a clear manifestation of an elastic, cavity rebound signal. We use modeling as the basis for understanding the observed phenomena

  14. Dynamics of Massive Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Chemke, Rei; Kaspi, Yohai, E-mail: rei.chemke@weizmann.ac.il [Department of Earth and Planetary Sciences, Weizmann Institute of Science, 234 Herzl st., 76100, Rehovot (Israel)

    2017-08-10

    The many recently discovered terrestrial exoplanets are expected to hold a wide range of atmospheric masses. Here the dynamic-thermodynamic effects of atmospheric mass on atmospheric circulation are studied using an idealized global circulation model by systematically varying the atmospheric surface pressure. On an Earth analog planet, an increase in atmospheric mass weakens the Hadley circulation and decreases its latitudinal extent. These changes are found to be related to the reduction of the convective fluxes and net radiative cooling (due to the higher atmospheric heat capacity), which, respectively, cool the upper troposphere at mid-low latitudes and warm the troposphere at high latitudes. These together decrease the meridional temperature gradient, tropopause height and static stability. The reduction of these parameters, which play a key role in affecting the flow properties of the tropical circulation, weakens and contracts the Hadley circulation. The reduction of the meridional temperature gradient also decreases the extraction of mean potential energy to the eddy fields and the mean kinetic energy, which weakens the extratropical circulation. The decrease of the eddy kinetic energy decreases the Rhines wavelength, which is found to follow the meridional jet scale. The contraction of the jet scale in the extratropics results in multiple jets and meridional circulation cells as the atmospheric mass increases.

  15. Reference Atmosphere for Mercury

    Science.gov (United States)

    Killen, Rosemary M.

    2002-01-01

    We propose that Ar-40 measured in the lunar atmosphere and that in Mercury's atmosphere is due to current diffusion into connected pore space within the crust. Higher temperatures at Mercury, along with more rapid loss from the atmosphere will lead to a smaller column abundance of argon at Mercury than at the Moon, given the same crustal abundance of potassium. Because the noble gas abundance in the Hermean atmosphere represents current effusion, it is a direct measure of the crustal potassium abundance. Ar-40 in the atmospheres of the planets is a measure of potassium abundance in the interiors, since Ar-40 is a product of radiogenic decay of K-40 by electron capture with the subsequent emission of a 1.46 eV gamma-ray. Although the Ar-40 in the Earth's atmosphere is expected to have accumulated since the late bombardment, Ar-40 in the atmospheres of Mercury and the Moon is eroded quickly by photoionization and electron impact ionization. Thus, the argon content in the exospheres of the Moon and Mercury is representative of current effusion rather than accumulation over the lifetime of the planet.

  16. Establishing atmospheric neutrino oscillations with Super-Kamiokande

    International Nuclear Information System (INIS)

    Kajita, T.; Kearns, E.; Shiozawa, M.

    2016-01-01

    In this article we review the discovery of atmospheric neutrino oscillation by the Super-Kamiokande experiment. This review outlines the sequence of observations and their associated publications that solved the atmospheric neutrino anomaly and established the existence of neutrino oscillations with nearly maximal mixing of muon neutrinos and tau neutrinos. We also discuss subsequent and ongoing studies that use atmospheric neutrinos to continue to reveal the nature of the neutrino.

  17. New atmospheric program

    Science.gov (United States)

    The National Science Foundation's Division of Atmospheric Sciences has established an Upper Atmospheric Facilities program within its Centers and Facilities section. The program will support the operation of and the scientific research that uses the longitudinal chain of incoherent scatter radars. The program also will ensure that the chain is maintained as a state-of-the-art research tool available to all interested and qualified scientists.For additional information, contact Richard A. Behnke, Division of Atmospheric Sciences, National Science Foundation, 1800 G Street, N.W., Washington, DC 20550 (telephone: 202-357-7390).

  18. Atmospheric ionisation in Snowdonia

    Energy Technology Data Exchange (ETDEWEB)

    Aplin, K L [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH UK (United Kingdom); Williams, J H, E-mail: k.aplin1@physics.ox.ac.uk [Envirodata-Eyri, Bryn Goleu, Penmaen Park, Llanfairfechan, Gwynedd LL33 0RL (United Kingdom)

    2011-06-23

    Atmospheric ionisation from natural radioactivity and cosmic rays has been measured at several sites in Snowdonia from 2005-present. The motivation for this project was a combination of public engagement with science, and research into the effects of ionisation on climate. A four-component atmospheric radiometer instrument is co-located with the ionisation detectors and the data is remotely logged and displayed on the Web. Atmospheric ionisation from natural radioactivity varies with local geology, and the cosmic ray ionisation component is modulated by solar activity and altitude. Variations due to all these effects have been identified and are described.

  19. Atmospheres of Brown Dwarfs

    Science.gov (United States)

    Wang, Ruoyan; Seay, Christopher

    2018-01-01

    We construct a grid of brown dwarf model atmospheres spanning a wide range of atmospheric metallicity (0.3x ≤ met ≤ 100x), C/O ratios (0.25x ≤ C/O ≤ 2.5x), and cloud properties, encompassing atmospheres of effective temperatures 200 ≤ Teff ≤ 2400 K and gravities 2.5 ≤ log g ≤ 5.5. We produce the expected temperature-pressure profiles and emergent spectra from an atmosphere in radiative-convective equilibrium. We can then compare our predicted spectra to observations and retrieval results to aid in their predictions and influence future missions and telescopic observations. In our poster we briefly describe our modeling methodology and present our progress on model grid construction, spanning solar and subsolar C/O and metallicity.

  20. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

    Africa and South India first detected the natural neutrinos and observed .... lucky coincidences, such as the angular diameter of the moon and sun being ... (where there is some peaking due to longer flight paths for pions in the atmosphere).

  1. Students 'Weigh' Atmospheric Pollution.

    Science.gov (United States)

    Caporaloni, Marina

    1998-01-01

    Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

  2. CARBON NEUTRON STAR ATMOSPHERES

    International Nuclear Information System (INIS)

    Suleimanov, V. F.; Klochkov, D.; Werner, K.; Pavlov, G. G.

    2014-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in the chemical composition of their atmospheres. For example, the atmospheres of thermally emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in Cas A, a pure carbon atmosphere has recently been suggested by Ho and Heinke. To test this composition for other similar sources, a publicly available detailed grid of the carbon model atmosphere spectra is needed. We have computed this grid using the standard local thermodynamic equilibrium approximation and assuming that the magnetic field does not exceed 10 8  G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra

  3. Exoplanet atmospheres physical processes

    CERN Document Server

    Seager, Sara

    2010-01-01

    Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introduction, examples that combine the relevant physics equations with real data, and exercises. Topics range from foundational knowledge, such as the origin of atmospheric composition and planetary spectra, to more advanced concepts, such as solutions to the radiative transfer equation, polarization, and molecular and condensate opacities. Since planets vary widely in their atmospheric properties, Seager emphasizes the major p...

  4. Origin of atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Marx, Gy [Eotvos Lorand Tudomanyegyetem, Budapest (Hungary). Atomfizikai Tanszek

    1975-01-01

    The evolution of the atmosphere of the Earth is described. Starting from the hot Universe the main steps of the ''cooling-down'' process as the different states of the condensation of the matter are discussed. After this nuclear evolution the chemical evolution could start on the solid Earth's crust. In the reductive primordial atmosphere mainly due to ultraviolet rays the basic molecules for life as sugars and amino acids were formed. The photosynthesis of the plants has later produced the oxygen being present in the recent atmosphere. The question whether pollution could affect the auto-stabilization loop of the atmosphere is also discussed. Finally the possibility of life on the Mars is studied.

  5. The origin of atmosphere

    International Nuclear Information System (INIS)

    Marx, Gy.

    1975-01-01

    The evolution of the atmosphere of the Earth is described. Starting from the hot Universe the main steps of the ''cooling-down'' process as the different states of the condensation of the matter are discussed. After this nuclear evolution the chemical evolution could start on the solid Earth's crust. In the reductive primordial atmosphere mainly due to ultraviolet rays the basic molecules for life as sugars and amino acids were formed. The photosynthesis of the plants has later produced the oxygen being present in the recent atmosphere. The question whether the pollution could affect the auto-stabilization loop of the atmosphere is also discussed. Finally the possibility of life on the Mars is studied. (Sz.Z.)

  6. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

  7. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  8. Intensifying the Atmospheric

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä

    2012-01-01

    The phenomenological concept of urban atmospheres is more often applied as an aesthetic description of the metropolitan space as such. This conceptualization is supported in this paper; however, I strive to give the concept a post-phenomenological axial turn. While phenomenology, due to its under...... sufficiently intense. All things considered, the paper should be read as a sociological contribution to theoretically reconstruct the concept of urban atmospheres in the light of spatial morphology....

  9. Atmospheric release advisory capability

    International Nuclear Information System (INIS)

    Sullivan, T.J.

    1981-01-01

    The ARAC system (Atmospheric Release Advisory Capability) is described. The system is a collection of people, computers, computer models, topographic data and meteorological input data that together permits a calculation of, in a quasi-predictive sense, where effluent from an accident will migrate through the atmosphere, where it will be deposited on the ground, and what instantaneous and integrated dose an exposed individual would receive

  10. Atmospheric pollution in Lisbon urban atmosphere

    Science.gov (United States)

    Oliveira, C.

    2009-04-01

    Lisbon is the capital city of Portugal with about 565,000 residents in 2008 and a population density of 6,600 inhabitants per square kilometre. Like several other major metropolis, the town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants, a quarter of the overall Portuguese population. Besides their local residents, it is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams, with important consequences on air pollution levels and obvious negative impacts on human health. Airborne particulate matter limit values are frequently exceeded, making urgent the existence of consistent programs to monitor and help taking measures to control them. Within the Portuguese project PAHLIS (Polycyclic Aromatic Hydrocarbons Contamination in Lisbon Urban Atmosphere) financed by the Portuguese Science Foundation ("Fundação para a Ciência e a Tecnologia"), an aerosol and vapour phase sampling program is being implemented in the city of Lisbon at two selected contrasting zones, namely a typically busy area with intense road traffic and frequent exceedences of the particulate matter standard for the maximum allowable concentration, and a residential quieter area, thus with a cleaner atmosphere characterised as an urban background site. An one month-long sampling campaign was performed during the summer of 2008, where particulate matter was collected in two fractions (coarse 2.5µmwork are expected to cover a lack of reliable information regarding sources of atmospheric pollutants in Portugal and present, for the first time, systematic data of PAHs levels in Lisbon. Acknowledgement: This work was performed under Project PAHLIS (PTDC/AMB/65699/2006) financed by "Fundação para a Ciência e a Tecnologia". C. Oliveira thanks Project PAHLIS his scholarship.

  11. Chemical and structural evolution in the Th-SeO3(2-)/SeO4(2-) system: from simple selenites to cluster-based selenate compounds.

    Science.gov (United States)

    Xiao, Bin; Langer, Eike; Dellen, Jakob; Schlenz, Hartmut; Bosbach, Dirk; Suleimanov, Evgeny V; Alekseev, Evgeny V

    2015-03-16

    While extensive success has been gained in the structural chemistry of the U-Se system, the synthesis and characterization of Th-based Se structures are widely unexplored. Here, four new Th-Se compounds, α-Th(SeO3)2, β-Th(SeO3)2, Th(Se2O5)2, and Th3O2(OH)2(SeO4)3, have been obtained from mild hydrothermal or low-temperature (180-220 °C) flux conditions and were subsequently structurally and spectroscopically characterized. The crystal structures of α-Th(SeO3)2 and β-Th(SeO3)2 are based on ThO8 and SeO3 polyhedra, respectively, featuring a three-dimensional (3D) network with selenite anions filling in the Th channels along the a axis. Th(Se2O5)2 is a 3D framework composed of isolated ThO8 polyhedra interconnected by [Se2O5](2-) dimers. Th3O2(OH)2(SeO4)3 is also a 3D framework constructed by octahedral hexathorium clusters [Th6(μ3-O)4(μ3-OH)4](12+), which are interlinked by selenate groups SeO4(2-). The positions of the vibrational modes associated with both Se(IV)O3(2-) and Se(VI)O4(2-) units, respectively, were determined for four compounds, and the Raman spectra of α- and β-Th(SeO3)2 are compared and discussed in detail.

  12. Atmospheric ions and pollution

    International Nuclear Information System (INIS)

    Renoux, A.

    1977-01-01

    The various types of atmospheric ions are defined, the main sources of natural atmospheric radioactivity inducing the formation of radioactive ions in the air are then recalled. The basic equations governing the formation of these ions are indicated and the most current experimental methods used for detecting them are described (Zeleny tubes, Erikson tubes). The special properties of these ions are examined, they are particularly emphasized for the smaller ones. The existence of a discret spectrum of mobilities is shown and the presence of big negative radioactive ions is investigated. Indicative information are given on the granulometric distribution of the atmospheric radioactivity in the air, from small positive Ra A ion fixation on aerosols [fr

  13. Phenomenology of atmospheric neutrinos

    Directory of Open Access Journals (Sweden)

    Fedynitch Anatoli

    2016-01-01

    Full Text Available The detection of astrophysical neutrinos, certainly a break-through result, introduced new experimental challenges and fundamental questions about acceleration mechanisms of cosmic rays. On one hand IceCube succeeded in finding an unambiguous proof for the existence of a diffuse astrophysical neutrino flux, on the other hand the precise determination of its spectral index and normalization requires a better knowledge about the atmospheric background at hundreds of TeV and PeV energies. Atmospheric neutrinos in this energy range originate mostly from decays of heavy-flavor mesons, which production in the phase space relevant for prompt leptons is uncertain. Current accelerator-based experiments are limited by detector acceptance and not so much by the collision energy. This paper recaps phenomenological aspects of atmospheric leptons and calculation methods, linking recent progress in flux predictions with particle physics at colliders, in particular the Large Hadron Collider.

  14. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...

  15. Composition of Estonian atmosphere

    International Nuclear Information System (INIS)

    Punning, J. M.; Karindi, A.

    1996-01-01

    Atmospheric study, particularly that of its chemical composition, has a long tradition in Estonia. Since middle of this century, in addition to meteorological observations, some chemical compounds in precipitations have been regularly measured in many meteorological stations. The main aim was to acquire information about the state and dynamics of the atmosphere. Therefore, main attention was paid to monitoring chemical compounds which have a direct impact on the human environment. As energy production developed intensively and SO 2 and NO x increased drastically in the atmosphere in acidic rock areas, like Scandinavia, the problem of acid rain became the most important environmental problem in Europe and North-America. As a consequence, monitoring the compounds of sulphur in precipitation was organized in Estonia. In the 1970 s, as related to large operating oil shale-based power plants, Estonia became a country , where emissions of sulphur compounds per capita were extremely high. In 1979, Estonia became a participant in the European Monitoring and Evaluation Programme - the network created to study transboundary air pollution. The aims of the precipitation chemistry study and the related problems of the formation and transformation of the atmospheric composition have varied over the years. But monitoring of pollutant (in particular, sulphur compound) loads has been a central issue. Over recent years, an attempt was made to estimate the spatial regularities of atmospheric impurities and their impact on the pH of mean monthly precipitations. Furthermore, calculations were provided to find out the origin of atmospheric impurities washed out in Estonia. Until the 1990 s, CO 2 , and some other greenhouse gas (GHG) emissions were not studied in Estonia. The first inventory of GHG for Estonia was provided in 1995 using the Intergovernmental Panel on Climate Change (IPCC) methodology

  16. Atmospheric correction of satellite data

    Science.gov (United States)

    Shmirko, Konstantin; Bobrikov, Alexey; Pavlov, Andrey

    2015-11-01

    Atmosphere responses for more than 90% of all radiation measured by satellite. Due to this, atmospheric correction plays an important role in separating water leaving radiance from the signal, evaluating concentration of various water pigments (chlorophyll-A, DOM, CDOM, etc). The elimination of atmospheric intrinsic radiance from remote sensing signal referred to as atmospheric correction.

  17. Natural atmospheric radioactivity

    International Nuclear Information System (INIS)

    Renoux, A.

    1986-01-01

    After having summed up the different old or new units, used in radioactivity and radioprotection, the origins of atmospheric radioactivity are reported. Next the authors deal with the air content in radon, thoron and their radioactive descendants, insisting on the variations of the radon air content and on the radioactive balance between radon and its descendants. Then a few notions concerning the natural radioactive aerosol are developed: electric charge state, granulometric distribution. The possible effects of natural atmospheric radioactivity on man are studied with a distinction between inner irradiation and outer irradiation, an average assessment is shown. Finally the important problem of radon in inhabitations is approached [fr

  18. Atmosphere beyond Poetics

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2014-01-01

    Defined by German philosopher Gernot Böhme as a ‘fundamental concept of a new aesthetics’ (Böhme 2003), the notion of atmosphere has been widely discussed across many disciplinary fields over the last few decades. It has taken a central stage also in architectural debate, leading to both conceptual......, the notion of atmosphere is presented as parallactic for designing experience in architectural fields, since it transgresses formal and material boundaries of bodies, opening a new gap that exposes the orthodox space-body-environment relationships to questions. It leads to the dissolution...

  19. Global atmospheric changes.

    Science.gov (United States)

    Piver, W T

    1991-12-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the processes that are responsible for the greenhouse effect, air pollution, acid deposition, and increased exposure to UV radiation.

  20. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    Crawford, T.V.

    1977-01-01

    The chairman and contributors are members of the Working Group on Atmospheric Dispersion, Deposition, and Resuspension. This group examined the mathematical approaches for determining the direct and indirect pathways to man of releases of pollutants to the atmosphere. The dose-to-man limitations promulgated by the Nuclear Regulatory Commission, the Environmental Protection Agency, and the Energy Research and Development Administration were presented. The present status of research was discussed, and recommendations for future work were made. Particular emphasis was placed on the need for additional experimental work to develop confidence limits leading to acceptable probability statements of critical pathways for determining the dose-to-man

  1. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    Crawford, T.V.

    1978-01-01

    The chairman and contributors are members of the Working Group on Atmospheric Dispersion, Deposition, and Resuspension. This group examined the mathematical approaches for determining the direct and indirect pathways to man of releases of pollutants to the atmosphere. The dose-to-man limitations promulgated by the Nuclear Regulatory Commission, the Environmental Protection Agency, and the Energy Research and Development Administration were presented. The present status of research was discussed, and recommendations for future work were made. Particular emphasis was placed on the need for additional experimental work to develop confidence limits leading to acceptable probability statements of critical pathways for determining the dose-to-man

  2. Seasonal atmospheric extinction

    International Nuclear Information System (INIS)

    Mikhail, J.S.

    1979-01-01

    Mean monochromatic extinction coefficients at various wavelengths at the Kottamia Observatory site have shown the existence of a seasonal variation of atmospheric extinction. The extinction of aerosol compontnts with wavelengths at winter represent exceedingly good conditions. Spring gives the highest extinction due to aerosol. (orig.)

  3. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  4. Atmospheric muons in Hanoi

    International Nuclear Information System (INIS)

    Pham Ngoc Diep; Pham thi Tuyet Nhung; Pierre Darriulat; Nguyen Thi Thao; Dang Quang Thieu; Vo Van Thuan

    2006-01-01

    Recent measurements of the atmospheric muon flux in Hanoi were reviewed. As the measurements were carried out in a region of maximal geomagnetic rigidity cutoff, they provided a sensitive test of air shower models used in the interpretation of neutrino oscillation experiments. The measured data were found to be in a very good agreement with the prediction from the model of M. Honda. (author)

  5. Climate and atmospheric research

    International Nuclear Information System (INIS)

    Kramer, G.; Schumacher, R.

    1992-01-01

    This issue of the scientific journal of the Humboldt university is dedicated to results of research work carried out to the greatest extent at the meteorological institute in the last two years on the area of climate and atmospheric research. The traditional research areas of the institute are climatology and the dynamics of the atmosphere, in particular the atmospherical boundary layer. Considering the high probability of a global climatic fluctuation due to the anthropogenic change of composition of the atmosphere and other climate-relevant factors imminent in the next century, climatological research today is an important part of global and regional environmental research. From the necessity of determination and evaluation of the effect of climatic fluctuations on nature and society the contours of a new interdisciplinary research area are already visible now. This is suitable as hardly any other area to be the supporting idea of environmental research at universities. The contributions contained in the issue already consider, in addition to results on climate diagnosis, also results on aspects of climate effect research. (orig./KW) [de

  6. Astronomy and Atmospheric Optics

    Science.gov (United States)

    Cowley, Les; Gaina, Alex

    2011-12-01

    The authors discusse the insuccess of the observation of the Total Eclipse of the Moon from 10 december 2011 in Romania and relate them with meteoconditions. Only a very short part of the last penumbral phase was observed, while the inital part and the totality was not observed due to very dense clouds. The change in color and brightness during this phase was signaled. Meanwhile, there is an area of science where clouds are of great use and interest. This area is Atmospheric optics, while the science which study clouds is meteorology. Clouds in combination with Solar and Moon light could give rise to a variety of strange, rare and unobvious phenomena in the atmosphere (sky), sometimes confused with Unidentified Flying Objects (UFO). The importance of meteorology for astronomy and atmospheric optics is underlined and an invitation to astronomers to use unfavourable days for athmospheric observations was sent. The web address of the site by Les Cowley, designed for atmospheric optics phenomena is contained in the text of the entry.

  7. Contaminants in the Atmosphere

    DEFF Research Database (Denmark)

    Skov, H.; Bossi, R.; Wåhlin, P.

    This report presents the results of atmospheric monitoring in Nuuk, Greenland. A long series of heavy metals and persistent organic Pollutants (POPs) have been measured and model calculations have been carried out supporting the interpretation of the results. Financially, the Danish Environmental...

  8. Atmospheric neutrino challenges

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor [Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)

    2005-08-15

    We briefly review the improvements in the predictions of atmospheric neutrino fluxes since the NOW2000 workshop. In spite of the great progress of the calculational technique the predictions are still not exact because of the uncertainties in the two major sets of input - cosmic ray flux and hadronic interactions on light nuclei.

  9. Atmosphere as colloid

    International Nuclear Information System (INIS)

    Kutsenogij, K.P.; Kutsenogij, P.K.

    2008-01-01

    In the paper review the results of experimental and theoretical investigations on space-time variability of physical, chemical and biological atmospheric characteristics and its influence on climate, ecology and environmental quality under the impact of natural processes and anthropogenic load is submitted

  10. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

    McNeill, V. Faye; Ariya, Parisa A.; McGill Univ. Montreal, QC

    2014-01-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  11. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Perkins, D.H.

    1984-01-01

    The atmospheric neutrino fluxes, which are responsible for the main background in proton decay experiments, have been calculated by two independent methods. There are discrepancies between the two sets of results regarding latitude effects and up-down asymmetries, especially for neutrino energies Esub(ν) < 1 GeV. (author)

  12. Atoms and atmosphere

    International Nuclear Information System (INIS)

    Megie, G.

    1994-01-01

    The ozone sources, roles and distribution are reviewed, and the atmosphere dynamic effects on ozone circulation are discussed; chlorine and CFC are the two main perturbative agents of the ozone layer and their effects are described and analyzed; impacts of the limitation of the CFC and chlorine utilization are discussed. 5 figs., 9 tabs

  13. ESA Atmospheric Toolbox

    Science.gov (United States)

    Niemeijer, Sander

    2017-04-01

    The ESA Atmospheric Toolbox (BEAT) is one of the ESA Sentinel Toolboxes. It consists of a set of software components to read, analyze, and visualize a wide range of atmospheric data products. In addition to the upcoming Sentinel-5P mission it supports a wide range of other atmospheric data products, including those of previous ESA missions, ESA Third Party missions, Copernicus Atmosphere Monitoring Service (CAMS), ground based data, etc. The toolbox consists of three main components that are called CODA, HARP and VISAN. CODA provides interfaces for direct reading of data from earth observation data files. These interfaces consist of command line applications, libraries, direct interfaces to scientific applications (IDL and MATLAB), and direct interfaces to programming languages (C, Fortran, Python, and Java). CODA provides a single interface to access data in a wide variety of data formats, including ASCII, binary, XML, netCDF, HDF4, HDF5, CDF, GRIB, RINEX, and SP3. HARP is a toolkit for reading, processing and inter-comparing satellite remote sensing data, model data, in-situ data, and ground based remote sensing data. The main goal of HARP is to assist in the inter-comparison of datasets. By appropriately chaining calls to HARP command line tools one can pre-process datasets such that two datasets that need to be compared end up having the same temporal/spatial grid, same data format/structure, and same physical unit. The toolkit comes with its own data format conventions, the HARP format, which is based on netcdf/HDF. Ingestion routines (based on CODA) allow conversion from a wide variety of atmospheric data products to this common format. In addition, the toolbox provides a wide range of operations to perform conversions on the data such as unit conversions, quantity conversions (e.g. number density to volume mixing ratios), regridding, vertical smoothing using averaging kernels, collocation of two datasets, etc. VISAN is a cross-platform visualization and

  14. Comets, impacts, and atmospheres

    Science.gov (United States)

    Owen, Tobias; Bar-Nun, Akiva

    Studies of element abundances and values of D/H in the atmospheres of the giant planets and Titan have emphasized the important role of icy planetesimals in the formation of these bodies. In these atmospheres, C/H and D/H increase as the relative masses of the 'cores' of the planets increase. N/H appears to deviate from this trend in an interesting way. In the inner solar system, the traditional approach of using carbonaceous chondrites as the source of planetary volatiles is in serious trouble because of the depletion of xenon and the unusual pattern of xenon isotopes found in the atmospheres of Earth and Mars, and because of the solar-type abundance ratios of argon, krypton and xenon and the large amounts of neon and argon on Venus. Recent studies of elemental abundances in comets, especially P/Halley, coupled with laboratory studies of the trapping of gas in ice formed at low temperatures by A. Bar-Nun et al. provide a consistent interpretation of all of these results. This interpretation emphasizes the fundamental importance of icy planetesimals (comets) and the randomness of early impacts in the formation of planetary systems. Cometary delivery by itself will not explain the noble gas abundances on the inner planets. There is good evidence for at least one additional source, which presumably consists of the rocky material making up the bulk of the planets. The existence of this rocky reservoir is manifested in the nucleogenic isotopes and in the neon which is found in all these atmospheres and is also present in the Earth's mantle. This neon may well be a relic of the planets' earliest, accretional atmospheres.

  15. Density imaging of volcanos with atmospheric muons

    OpenAIRE

    Fehr , F.

    2011-01-01

    collaboration : TOMUVOL; International audience; Their capability to penetrate large depths of material renders high-energy atmospheric muons a unique probe for geophysical explorations. Provided the topography of the target is known, the measurement of the attenuation of the muon flux permits the cartography of matter density distributions revealing spatial and possibly also temporal variations in extended geological structures. A Collaboration between volcanologists, astroparticle- and part...

  16. Thomson scattering measurements in atmospheric plasma jets

    International Nuclear Information System (INIS)

    Gregori, G.; Schein, J.; Schwendinger, P.; Kortshagen, U.; Heberlein, J.; Pfender, E.

    1999-01-01

    Electron temperature and electron density in a dc plasma jet at atmospheric pressure have been obtained using Thomson laser scattering. Measurements performed at various scattering angles have revealed effects that are not accounted for by the standard scattering theory. Differences between the predicted and experimental results suggest that higher order corrections to the theory may be required, and that corrections to the form of the spectral density function may play an important role. copyright 1999 The American Physical Society

  17. Influence of autochthonous micro-organisms on sorption and remobilization of technetium and selenium. Final report; Einfluss der autochthonen Mikroflora auf die Sorption und Remobilisierung des Technetiums und des Selens. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Maue, G.; Stroetmann, I.; Dott, W. [Technische Univ. Berlin (Germany). Fachgebiet Umwelthygiene; Taute, T.; Winkler, A.; Pekdeger, A. [Freie Univ. Berlin (Germany). Fachrichtung Rohstoff- und Umweltgeologie

    1996-10-31

    Within this research project the influence of autochthonous mirco-organisms on immobilization and remobilization of Technetium and Selenium was investigated. Both redoxsensitive radionuclides are part of the waste of nuclear fuel (Tc app. 6%). Former investigations have shown, that immobilization behaviour of both elements could be influenced by micro-organisms. It has not been known, if the autochthonous (or in situ) organisms from greater depth do also have an influence on radionuclide mobility. The autochthonous populations of micro-organisms in deep sediments and their influence on the migration of Tc and Se were investigated in this study. For this reason recirculation column experiments were carried out. Absolutely sterile and anaerobic handling was necessary for the sampling and the further treatment of the sediments and waters used in the experiments. Therefor special methods for sampling, storage and handling had been developed. The results of recirculation column test with autochthonous micro-organisms were compared with sterile parallel tests and were verified with the results of an elaborated version of the hydrogeochemical equilibration code PHREEQE. It was shown that the autochthonous micro-organisms had only very little influence on the migration behaviour. The reason is the very low population (less than 10 E+6 CFU). Nevertheless it has to be taken into consideration, that conventional laboratory experiments for the estimation of the retention capacities of sediments for hazardous waste lead to an overestimation, if the sediments are contaminated with allochthonous micro-organisms (CFU=colony forming units). (orig.) [Deutsch] In dem Forschungsvorhaben wurde der Einfluss der autochthonen Mikroorgansimen auf die Mobilitaet von Technetium und Selen untersucht. Beide redoxsensitiven Radionuklide sind im Abfall von Kernbrennelementen enthalten (Tc ca. 6%). Aus vorangegangenen Forschungsarbeiten ist bekannt, dass die Mobilitaet der beiden Elemente durch

  18. Lichens and atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, J H

    1964-09-01

    The extreme sensitivity of lichens, particularly the larger ones, to industrialization has been recognized for many years. Most people attribute the absence of lichens from urban areas to the atmospheric pollution prevailing, and a few attribute it to climatic dryness, resulting from efficient drainage systems in towns. The two main components of air pollution are solid matter, or soot, and gaseous sulfur dioxide. The main effects of pollution appear to be: a direct reduction of light intensity by smoke haze, a deposit of soot on the plant surface, an acidification of the soil, and direct damage to plants. A body of evidence indicates that SO/sub 2/ may be the main harmful component for lichens. The distribution of lichens thus might be used to determine the limits within which atmospheric pollution is operating. 5 references.

  19. Atmospheric Release Advisory Capability

    International Nuclear Information System (INIS)

    Dickerson, M.H.; Gudiksen, P.H.; Sullivan, T.J.

    1983-02-01

    The Atmospheric Release Advisory Capability (ARAC) project is a Department of Energy (DOE) sponsored real-time emergency response service available for use by both federal and state agencies in case of a potential or actual atmospheric release of nuclear material. The project, initiated in 1972, is currently evolving from the research and development phase to full operation. Plans are underway to expand the existing capability to continuous operation by 1984 and to establish a National ARAC Center (NARAC) by 1988. This report describes the ARAC system, its utilization during the past two years, and plans for its expansion during the next five to six years. An integral part of this expansion is due to a very important and crucial effort sponsored by the Defense Nuclear Agency to extend the ARAC service to approximately 45 Department of Defense (DOD) sites throughout the continental US over the next three years

  20. Outer atmospheric research

    International Nuclear Information System (INIS)

    Anderson, J.L.

    1988-01-01

    The region above the earth from about 90 km to 150 km is a major part of the upper or outer atmosphere. It is relatively unexplored, being too high for balloons or aircraft and too low for persistent orbiting spacecraft. However, the concept of a tethered subsatellite, deployed downward from an orbiting, more massive craft such as the Space Shuttle, opens the possibility of a research capability that could provide global mapping of this region. The need for research in this thick spherical shell above the earth falls into two major categories: (1) scientific data for understanding and modeling the global atmosphere and thereby determining its role in the earth system, and (2) engineering data for the design of future aerospace vehicles that will operate there. This paper presents an overview and synthesis of the currently perceived research needs and the state-of-the-art of the proposed tethered research capability. 16 references

  1. Atmospheric Science Without Borders

    Science.gov (United States)

    Panday, Arnico; Praveen, Ps; Adhikary, Bhupesh; Bhave, Prakash; Surapipith, Vanisa; Pradhan, Bidya; Karki, Anita; Ghimire, Shreta; Thapa, Alpha; Shrestha, Sujan

    2016-04-01

    The Indo-Gangetic Plains (IGP) in northern South Asia are among the most polluted and most densely populated places in the world, and they are upwind of vulnerable ecosystems in the Himalaya mountains. They are also fragmented across 5 countries between which movement of people, data, instruments and scientific understanding have been very limited. ICIMOD's Atmosphere Initiative has for the past three years been working on filling data gaps in the region, while facilitating collaborations across borders. It has established several atmospheric observatories at low and mid elevations in Bhutan and Nepal that provide new data on the inflow of pollutants from the IGP towards the mountains, as well as quantify the effects of local emissions on air quality in mountain cities. EGU will be the first international conference where these data will be presented. ICIMOD is in the process of setting up data servers through which data from the region will be shared with scientists and the general public across borders. Meanwhile, to promote cross-border collaboration among scientists in the region, while addressing an atmospheric phenomenon that affects the lives of the several hundred million people, ICIMOD' Atmosphere Initiative has been coordinating an interdisciplinary multi-year study of persistent winter fog over the Indo-Gangetic Plains, with participation by researchers from Pakistan, India, China, Nepal, Bhutan and Bangladesh. Using a combination of in-situ measurements and sample collection, remote sensing, modeling and community based research, the researchers are studying how changing moisture availability and air pollution have led to increases in fog frequency and duration, as well as the fog's impacts on local communities and energy demand that may affect air pollution emissions. Preliminary results of the Winter 2015-2016 field campaign will be shown.

  2. Atmospheric tides on Neptune

    International Nuclear Information System (INIS)

    Dement'ev, M.S.; Morozhenko, A.V.

    1989-01-01

    The dependence of the equivalent width of the methane absorption band at 619 nm in the Neptune's spectrum upon the Triton's orbital position is discovered. It is assumed that observed changes of the equivalent width of the band and colour index (J - K) (Belton et al., 1981; Brown et al., 1981; Cruikshank, 1978) are due to atmospheric tides (period 2 d .9375) and Neptune's rotation (period 10 h .14)

  3. Dreaming of Atmospheres

    Science.gov (United States)

    Waldmann, I. P.

    2016-04-01

    Here, we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrieval of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated, and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst-case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep-belief neural (DBN) networks trained to accurately recognize molecular signatures for a wide range of planets, atmospheric thermal profiles, and compositions. Reconstructions of the learned features, also referred to as the “dreams” of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work toward retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data, and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process.

  4. Atmospheric benzene and toluene

    International Nuclear Information System (INIS)

    Rasmussen, R.A.; Khalil, M.A.K.

    1983-01-01

    Atmospheric concentrations of benzene (C 6 H 6 ) and toluene (C 7 H 8 )have been observed at nine remote locations of the world ranging in latitude from inside the arctic circle to the south pole. The observations span all seasons at each location. In the northern hemisphere it is observed that C 6 H 6 and C 7 H 8 are most abundant during winter and least abundant during summer. Based on the limited data available, such cycles are not observed in the tropics. These findings are consistent with the expected latitudinal and seasonal variations of OH radicals which cause benzene and toluene to be removed from the atmosphere. The latitude distribution shows high concentrations at mid latitude and low levels in the southern hemisphere. This finding is consistent with the present understanding that the sources of benzene and toluene are primarily anthropogenic. The observed concentration distribution and varibility are consistent with the short expected atmospheric lifetime of the order of months for benzene and days for toluene

  5. DREAMING OF ATMOSPHERES

    International Nuclear Information System (INIS)

    Waldmann, I. P.

    2016-01-01

    Here, we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrieval of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated, and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst-case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep-belief neural (DBN) networks trained to accurately recognize molecular signatures for a wide range of planets, atmospheric thermal profiles, and compositions. Reconstructions of the learned features, also referred to as the “dreams” of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work toward retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data, and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process

  6. Atmospheric radiation monitor

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M.A. Leigui de; Peixoto, C.J. Todero; Leao, M.S.A.B.; Luzio, V.P. [Universidade Federal do ABC (UFABC), SP (Brazil); Barbosa, A.F.; Lima Junior, H.P.; Vilar, A.B.; Gama, R.G.; Ferraz, V.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Full text: The Atmospheric Radiation Monitor (MonRAt) is a compact telescope designed to detect fluorescence photons generated in the atmosphere by ultra-high energy cosmic rays showers with energies in the interval between 10{sup 17} eV and 10{sup 18} eV. It is composite by a 64 pixels MultiAnodic PhotoMultiplier Tube (MAPMT) placed at the focus of a parabolic mirror mounted in a Newtonian telescope setup and the data acquisition system. In front of the MAPMT photocathode, filters will be positioned to select light with wavelength in the near ultraviolet region (300 nm < {lambda} < 450 nm) where the nitrogen fluorescent emissions occurs. The data acquisition system consists of a set of pre-amplifiers and FPGA-based boards able to record trigger times and waveforms from each channel and send the data to a computer by USB ports. MonRAt will be used to detect fluorescence photons under different atmospheric conditions (pressure, temperature, humidity, local geomagnetic field, etc) and will contribute with a detailed study of the fluorescence radiation yield. The assembly of the telescope is under way and we present in this work the status of the experiment and its first measurements in the laboratory. (author)

  7. Atmospheric radiation monitor

    International Nuclear Information System (INIS)

    Oliveira, M.A. Leigui de; Peixoto, C.J. Todero; Leao, M.S.A.B.; Luzio, V.P.; Barbosa, A.F.; Lima Junior, H.P.; Vilar, A.B.; Gama, R.G.; Ferraz, V.A.

    2011-01-01

    Full text: The Atmospheric Radiation Monitor (MonRAt) is a compact telescope designed to detect fluorescence photons generated in the atmosphere by ultra-high energy cosmic rays showers with energies in the interval between 10 17 eV and 10 18 eV. It is composite by a 64 pixels MultiAnodic PhotoMultiplier Tube (MAPMT) placed at the focus of a parabolic mirror mounted in a Newtonian telescope setup and the data acquisition system. In front of the MAPMT photocathode, filters will be positioned to select light with wavelength in the near ultraviolet region (300 nm < λ < 450 nm) where the nitrogen fluorescent emissions occurs. The data acquisition system consists of a set of pre-amplifiers and FPGA-based boards able to record trigger times and waveforms from each channel and send the data to a computer by USB ports. MonRAt will be used to detect fluorescence photons under different atmospheric conditions (pressure, temperature, humidity, local geomagnetic field, etc) and will contribute with a detailed study of the fluorescence radiation yield. The assembly of the telescope is under way and we present in this work the status of the experiment and its first measurements in the laboratory. (author)

  8. The Atmospheric Boundary Layer

    Science.gov (United States)

    Garratt, J. R.

    1994-05-01

    A comprehensive and lucid account of the physics and dynamics of the lowest one to two kilometers of the Earth's atmosphere in direct contact with the Earth's surface, known as the atmospheric boundary layer (ABL). Dr. Garratt emphasizes the application of the ABL problems to numerical modeling of the climate, which makes this book unique among recent texts on the subject. He begins with a brief introduction to the ABL before leading to the development of mean and turbulence equations and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modeling of the ABL is crucially dependent for its realism on the surface boundary conditions, so chapters four and five deal with aerodynamic and energy considerations, with attention given to both dry and wet land surfaces and the sea. The author next treats the structure of the clear-sky, thermally stratified ABL, including the convective and stable cases over homogeneous land, the marine ABL, and the internal boundary layer at the coastline. Chapter seven then extends this discussion to the cloudy ABL. This is particularly relevant to current research because the extensive stratocumulus regions over the subtropical oceans and stratus regions over the Arctic have been identified as key players in the climate system. In the final chapters, Dr. Garratt summarizes the book's material by discussing appropriate ABL and surface parameterization schemes in general circulation models of the atmosphere that are being used for climate stimulation.

  9. DREAMING OF ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Waldmann, I. P., E-mail: ingo@star.ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT (United Kingdom)

    2016-04-01

    Here, we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrieval of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated, and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst-case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep-belief neural (DBN) networks trained to accurately recognize molecular signatures for a wide range of planets, atmospheric thermal profiles, and compositions. Reconstructions of the learned features, also referred to as the “dreams” of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work toward retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data, and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process.

  10. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J. (Discovery Bay Marine Laboratory, Univ. of the West Indies (JM))

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  11. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T J [Discovery Bay Marine Laboratory, Univ. of the West Indies (JM)

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  12. Determination of the Atmospheric Neutrino Fluxes from Atmospheric Neutrino Data

    NARCIS (Netherlands)

    Gonzalez-Garcia, M. C.; Maltoni, M.; Rojo, J.

    2006-01-01

    The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard atmospheric neutrino data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based

  13. Frontiers in Atmospheric Chemistry Modelling

    Science.gov (United States)

    Colette, Augustin; Bessagnet, Bertrand; Meleux, Frederik; Rouïl, Laurence

    2013-04-01

    The first pan-European kilometre-scale atmospheric chemistry simulation is introduced. The continental-scale air pollution episode of January 2009 is modelled with the CHIMERE offline chemistry-transport model with a massive grid of 2 million horizontal points, performed on 2000 CPU of a high performance computing system hosted by the Research and Technology Computing Center at the French Alternative Energies and Atomic Energy Commission (CCRT/CEA). Besides the technical challenge, which demonstrated the robustness of the selected air quality model, we discuss the added value in terms of air pollution modelling and decision support. The comparison with in-situ observations shows that model biases are significantly improved despite some spurious added spatial variability attributed to shortcomings in the emission downscaling process and coarse resolution of the meteorological fields. The increased spatial resolution is clearly beneficial for the detection of exceedances and exposure modelling. We reveal small scale air pollution patterns that highlight the contribution of city plumes to background air pollution levels. Up to a factor 5 underestimation of the fraction of population exposed to detrimental levels of pollution can be obtained with a coarse simulation if subgrid scale correction such as urban increments are ignored. This experiment opens new perspectives for environmental decision making. After two decades of efforts to reduce air pollutant emissions across Europe, the challenge is now to find the optimal trade-off between national and local air quality management strategies. While the first approach is based on sectoral strategies and energy policies, the later builds upon new alternatives such as urban development. The strategies, the decision pathways and the involvement of individual citizen differ, and a compromise based on cost and efficiency must be found. We illustrated how high performance computing in atmospheric science can contribute to this

  14. Atmospheric Radiation Measurement Program Plan

    International Nuclear Information System (INIS)

    1990-02-01

    In order to understand energy's role in anthropogenic global climate change, significant reliance is being placed on General Circulation Models (GCMs). A major goal of the Department is to foster the development of GCMs capable of predicting the timing and magnitude of greenhouse gas-induced global warming and the regional effects of such warming. DOE research has revealed that cloud radiative feedback is the single most important effect determining the magnitude of possible climate responses to human activity. However, cloud radiative forcing and feedbacks are not understood at the levels needed for reliable climate prediction. The Atmospheric Radiation Measurement (ARM) Program will contribute to the DOE goal by improving the treatment of cloud radiative forcing and feedbacks in GCMs. Two issues will be addressed: the radiation budget and its spectral dependence and the radiative and other properties of clouds. Understanding cloud properties and how to predict them is critical because cloud properties may very well change as climate changes. The experimental objective of the ARM Program is to characterize empirically the radiative processes in the Earth's atmosphere with improved resolution and accuracy. A key to this characterization is the effective treatment of cloud formation and cloud properties in GCMs. Through this characterization of radiative properties, it will be possible to understand both the forcing and feedback effects. GCM modelers will then be able to better identify the best approaches to improved parameterizations of radiative transfer effects. This is expected to greatly improve the accuracy of long-term, GCM predictions and the efficacy of those predictions at the important regional scale, as the research community and DOE attempt to understand the effects of greenhouse gas emissions on the Earth's climate. 153 refs., 24 figs., 6 tabs

  15. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  16. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and

  17. Heat transfer in the atmosphere

    NARCIS (Netherlands)

    Oerlemans, J.

    1982-01-01

    The atmosphere is almost transparent to solar radiation and almost opaque to terrestrial radiation. This implies that in the mean the atmosphere cools while the earth's surface is heated. Convection in the lower atmosphere must therefore occur. The upward flux of energy associated with it

  18. Atmospheric tritium. Measurement and application

    International Nuclear Information System (INIS)

    Frejaville, Gerard

    1967-02-01

    The possible origins of atmospheric tritium are reviewed and discussed. A description is given of enrichment (electrolysis and thermal diffusion) and counting (gas counters and liquid scintillation counters) processes which can be used for determining atmospheric tritium concentrations. A series of examples illustrates the use of atmospheric tritium for resolving a certain number of hydrological and glaciological problems. (author) [fr

  19. Titan's hydrodynamically escaping atmosphere

    Science.gov (United States)

    Strobel, Darrell F.

    2008-02-01

    The upper atmosphere of Titan is currently losing mass at a rate ˜(4-5)×10 amus, by hydrodynamic escape as a high density, slow outward expansion driven principally by solar UV heating by CH 4 absorption. The hydrodynamic mass loss is essentially CH 4 and H 2 escape. Their combined escape rates are restricted by power limitations from attaining their limiting rates (and limiting fluxes). Hence they must exhibit gravitational diffusive separation in the upper atmosphere with increasing mixing ratios to eventually become major constituents in the exosphere. A theoretical model with solar EUV heating by N 2 absorption balanced by HCN rotational line cooling in the upper thermosphere yields densities and temperatures consistent with the Huygens Atmospheric Science Investigation (HASI) data [Fulchignoni, M., and 42 colleagues, 2005. Nature 438, 785-791], with a peak temperature of ˜185-190 K between 3500-3550 km. This model implies hydrodynamic escape rates of ˜2×10 CHs and 5×10 Hs, or some other combination with a higher H 2 escape flux, much closer to its limiting value, at the expense of a slightly lower CH 4 escape rate. Nonthermal escape processes are not required to account for the loss rates of CH 4 and H 2, inferred by the Cassini Ion Neutral Mass Spectrometer (INMS) measurements [Yelle, R.V., Borggren, N., de la Haye, V., Kasprzak, W.T., Niemann, H.B., Müller-Wodarg, I., Waite Jr., J.H., 2006. Icarus 182, 567-576].

  20. Atmospheric natural radioactivity outdoors

    International Nuclear Information System (INIS)

    Renoux, A.

    1985-01-01

    Following a short account of natural atmospheric radioactivity, radon concentrations are given as well as their variations with time obtained by means of a original apparatus developped in Brest. The radioactive equilibrium of radon and its daughters is then considered, many experiments demonstrating that equilibrium is seldom reached even for 218 Po (RaA). Finally, some characteristics of natural radioactive aerosols are studied: charge, particle size distribution (demonstrating they are fine aerosols since only 30 per cent are made of particles with radii exceeding 0,1 μm) [fr

  1. Atmospheres of central stars

    International Nuclear Information System (INIS)

    Hummer, D.G.

    1978-01-01

    The author presents a brief summary of atmospheric models that are of possible relevance to the central stars of planetary nebulae, and then discusses the extent to which these models accord with the observations of both nebulae and central stars. Particular attention is given to the significance of the very high Zanstra temperature implied by the nebulae He II lambda 4686 A line, and to the discrepancy between the Zanstra He II temperature and the considerably lower temperatures suggested by the appearance of the visual spectrum for some of these objects. (Auth.)

  2. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Honda, M.; Kasahara, K.; Hidaka, K.; Midorikawa, S.

    1990-02-01

    A detailed Monte Carlo simulation of neutrino fluxes of atmospheric origin is made taking into account the muon polarization effect on neutrinos from muon decay. We calculate the fluxes with energies above 3 MeV for future experiments. There still remains a significant discrepancy between the calculated (ν e +antiν e )/(ν μ +antiν μ ) ratio and that observed by the Kamiokande group. However, the ratio evaluated at the Frejus site shows a good agreement with the data. (author)

  3. Rectenna related atmospheric effects

    Science.gov (United States)

    Lee, J.

    1980-01-01

    Possible meteorological effects arising from the existence and operations of a solar power satellite (SPS) system rectenna are examined. Analysis and model simulations in some chosen site situations and meteorological conditions indicate that the meteorological effects of the construction and operation of a rectenna are small, particularly outside the boundary of the structure. From weather and climate points of view, installation of an SPS rectenna seems likely to have effects comparable with those due to other nonindustrial land use changes covering the same area. The absorption and scattering of microwave radiation in the troposphere would have negligible atmospheric effects.

  4. Effects in atmospheric electricity daily variation controlled by solar wind

    International Nuclear Information System (INIS)

    Ptitsyna, N.G.; Tyasto, M.I.; Levitin, A.E.; Gromova, L.A.; Tuomi, T.; AN SSSR, Moscow

    1995-01-01

    An analysis of fair weather atmospheric electricity, one of the environmental factors which affects the biosphere, is conducted. A distinct difference in the diurnal variation of atmospheric electric field at Helsinki is found between disturbed and extremely quiet conditions in the magnetosphere in winter before midnight. The comparison with the numerical model of the ionospheric electric field based on the solar wind parameters reveals that the maximum contribution of the magnetospheric-ionospheric generator to atmospheric electric field is about 100-150 v/m which assumes values of about 30% of the surface field. 8 refs.; 2 figs

  5. Soodusrenoveerimine kogub hoogu / Selene-Rete Rebane

    Index Scriptorium Estoniae

    Rebane, Selene-Rete

    2002-01-01

    Tallinna kultuuriväärtuste ameti poolt koos erafirmadega käivitatud projekti "Vana maja korda" raames restaureeritakse puitmajde uksi ning väljastatkse värvipasse, mille alusel saab soodushinnaga fassaadivärve osta

  6. Influence of atmospheric pressure on infrarenal abdominal aortic aneurysm rupture.

    Science.gov (United States)

    Robert, Nicolas; Frank, Michael; Avenin, Laure; Hemery, Francois; Becquemin, Jean Pierre

    2014-04-01

    Meteorologic conditions have a significant impact on the occurrence of cardiovascular events. Previous studies have shown that abdominal aortic aneurysm rupture (AAAR) may be associated with atmospheric pressure, with conflicting results. Therefore, we aimed to further investigate the nature of the correlation between atmospheric pressure variations and AAAR. Hospital admissions related to AAAR between 2005-2009 were assessed in 19 districts of metropolitan France and correlated with geographically and date-matched mean atmospheric pressures. In parallel and from 2005-2009, all fatal AAARs as reported by death certificates were assessed nationwide and correlated to local atmospheric pressures at the time of aortic rupture. Four hundred ninety-four hospital admissions related to AAAR and 6,358 deaths nationwide by AAAR were identified between 2005-2009. Both in-hospital ruptures and aneurysm-related mortality had seasonal variations, with peak/trough incidences in January and June, respectively. Atmospheric pressure peaks occurred during winter. Univariate analysis revealed a significant association (P atmospheric pressure values and AAAR. After multivariate analysis, mean maximum 1-month prerupture atmospheric pressure had a persistent correlation with both in-hospital relative risk (1.05 [95% confidence interval: 1.03-1.06]; P atmospheric pressure. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.

    1989-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10/sup 7/ was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H/sub 2/O to the stream entering the molecular sieve and premoistening of the sieve with H/sub 2/O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled

  8. 13. Atmosphere and climate

    International Nuclear Information System (INIS)

    Mock, G.; Hammond, A.

    1992-01-01

    This chapter reports on past and current trends in the major forms of atmospheric pollution and on the relative contributions of the countries of the world to these emissions. It also reports on emissions of carbon dioxide from industrial processes - principally the combustion of fossil fuels - which is the largest single source of greenhouse gases and an appropriate target for initial efforts to limit emissions. Discussions are presented on the following: urban air pollution - sources, trends and effects (particulates, sulfur dioxide, smog and its precursors, indoor air pollution, carbon monoxide, lead); regional air pollution - sources, trends and effects (acid deposition, ground-level ozone, regional responses and emission trends, acceleration of ozone depletion); solutions (cleaning up stationary sources, corporate responsibility movement, reducing vehicle pollution); global climate treaty talks proceed; greenhouse gas emissions; and targets for limiting emissions

  9. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.; Los Alamos National Lab., NM; Princeton Univ., NJ

    1988-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10 7 was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H 2 O to the stream entering the molecular sieve and premoistening of the sieve with H 2 O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled. 13 refs., 4 figs

  10. Habituating alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie

    This paper proposes embodied rhythmic sound habituation as a possible resource when designing contextualized technologies in critical atmospheres. The main contribution is collating the concept of rhythm as presented by Henri Lefebvre with the concept of sound habituation to help operationalize...... functionality for the staff, but are stressful for visitors and patients, as they are designed to demand attention even though they have no direct functional meaning to them. By introducing sounds from the ward, integrated in the furniture as simple sound sample triggers, KidKit invites children to become...... accustomed to the alarming sounds through rhythmic interaction in the waiting room, and bringing the furniture with them afterwards as a secure anchor, when entering the ward. This rhythmic habituation can enable the child to focus her attention on the meeting with the hospitalized relative....

  11. Synthesis and crystal structure of new uranyl selenite(IV)-selenate(VI) [C5H14N][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)(HSeO4)

    International Nuclear Information System (INIS)

    Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F.; Kalenberg, V.

    2006-01-01

    Crystals of new uranyl selenite(IV)-selenate(VI) [C 5 H 14 N][(UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)](H 2 SeO 3 )(HSeO 4 ) are obtained by the method of evaporation from aqueous solutions. Compound has triclinic lattice, space group P1-bar, a=11.7068(9), b=14.8165(12), c=16.9766(15), α=73.899(6), β=76.221(7), γ=89.361(6) Deg, V=2743.0(4) A 3 , Z=2. Laminated complexes (UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)] 3- are the basis of the structure. [HSe(VI)O 4 ] - , [H 2 Se(IV)O 3 ] complexes and protonated methylbutylamine cations are disposed between layers [ru

  12. Atmospheric turbulence and diffusion research

    International Nuclear Information System (INIS)

    Hosker, R.P. Jr.

    1993-01-01

    The Atmospheric Turbulence and Diffusion Division (well known in the atmospheric dispersion community as the Atmospheric Turbulence and Diffusion Laboratory, ATDL) is one of several field facilities of NOAAs Air Resources Laboratory, headquartered in Silver Spring, Maryland. The laboratory conducts research on matters of atmospheric diffusion and turbulent exchange, concerning air quality. ATDD focuses attention on the physics of the lower atmosphere, with special emphasis on the processes contributing to atmospheric transport, dispersion, deposition, and air-surface exchange, and on the development of predictive capabilities using the results of this research. Research is directed toward issues of national and global importance related to the missions of DOE, to DOE's Oak Ridge Field Office, and to NOAA. The program is divided into four major projects: plume transport and diffusion in the planetary boundary layer, complex topography, canopy micrometeorology, and air-surface exchange

  13. Stochastic background of atmospheric cascades

    International Nuclear Information System (INIS)

    Wilk, G.; Wlodarczyk, Z.

    1993-01-01

    Fluctuations in the atmospheric cascades developing during the propagation of very high energy cosmic rays through the atmosphere are investigated using stochastic branching model of pure birth process with immigration. In particular, we show that the multiplicity distributions of secondaries emerging from gamma families are much narrower than those resulting from hadronic families. We argue that the strong intermittent like behaviour found recently in atmospheric families results from the fluctuations in the cascades themselves and are insensitive to the details of elementary interactions

  14. Planetary Surface-Atmosphere Interactions

    Science.gov (United States)

    Merrison, J. P.; Bak, E.; Finster, K.; Gunnlaugsson, H. P.; Holstein-Rathlou, C.; Knak Jensen, S.; Nørnberg, P.

    2013-09-01

    Planetary bodies having an accessible solid surface and significant atmosphere, such as Earth, Mars, Venus, Titan, share common phenomenology. Specifically wind induced transport of surface materials, subsequent erosion, the generation and transport of solid aerosols which leads both to chemical and electrostatic interaction with the atmosphere. How these processes affect the evolution of the atmosphere and surface will be discussed in the context of general planetology and the latest laboratory studies will be presented.

  15. A glossary of atmospheric science

    International Nuclear Information System (INIS)

    1996-09-01

    This book concentrates on the glossary of atmospheric science, which contains summary, for enactment and deliberation on choosing special glossary on atmospheric science in Korea, examiner for the glossary on atmospheric science, reference, explanatory notes and a lot of glossary on atmospheric science. It also has an appendix on commercial abbreviation, prefix, unit, wavelength and the number o vibrations of electromagnetic waves, ICAO classified catalogue on cloud, list of varietal cloud and list of local wind. It has explanation of the glossary in English, Korea, China and Japan.

  16. Kajian Pustaka Mengenai Restaurant Atmosphere

    Directory of Open Access Journals (Sweden)

    Adeline Agoes

    2015-05-01

    Full Text Available Restaurant is one of the businesses that support tourism development. Restaurants nowadays don’t only provide food, but also the service and atmosphere to their customers. The purpose of this study is to discover theaspects defining restaurant atmosphere and the implications of restaurant atmosphere to other particular aspects related to restaurant business. This article is written based on a study conducted through a literature review. Through the examination, it is found that the atmosphere of a restaurant is one important aspect and can be considered as a competitive advantage as well as one of the determinants of customer satisfaction.

  17. Anthropogenous modifications of the atmosphere. The atmospheric ozone threat

    International Nuclear Information System (INIS)

    Aimedieu, P.

    1991-01-01

    Ozone role and atmospheric chemistry are first reviewed: chemical reactions and vertical distribution of ozone in the atmosphere. The origins of chlorofluorocarbon air pollution and the role of the various types of CFC on ozone depletion, greenhouse effect, cancer, etc. are then discussed. The political and environmental discussions concerning these phenomena are also reviewed

  18. Jets in Planetary Atmospheres

    Science.gov (United States)

    Dowling, Tim

    2018-05-01

    Jet streams, "jets" for short, are remarkably coherent streams of air found in every major atmosphere. They have a profound effect on a planet's global circulation, and have been an enigma since the belts and zones of Jupiter were discovered in the 1600s. The study of jets, including what processes affect their size, strength, direction, shear stability, and predictability, are active areas of research in geophysical fluid dynamics. Jet research is multidisciplinary and global, involving collaborations between observers, experimentalists, numerical modelers, and applied mathematicians. Jets in atmospheres have strong analogies with shear instability in nonneutral plasmas, and these connections are highlighted throughout the article. The article begins with a description of four major challenges that jet researchers face: nonlinearity, non-intuitive wave physics, non-constant-coefficients, and copious nondimensional numbers. Then, two general fluid-dynamical tenets, the practice of rendering expressions dimensionally homogeneous (nondimensional), and the universal properties of shocks are applied to the open question of what controls the on-off switch of shear instability. The discussion progresses to how the physics of jets varies in equatorial, midlatitude, and polar regions, and how jets are observed to behave in each of these settings. The all-in-one conservation law of potential vorticity (PV), which combines the conservation laws of mass, momentum, and thermal energy into a single expression, is the common language of jet research. Earth and Uranus have weak retrograde equatorial jets, but most planets exhibit super-rotating equatorial jets, which require eddies to transport momentum up gradient in a non-intuitive manner. Jupiter and Saturn exhibit multiple alternating jets in their midlatitudes. The theory for why jets are invariably zonal (east-west orientated) is reviewed, and the particular challenges that Jupiter's sharp westward jets present to existing

  19. Characteristics in mineral compositions of lunar latest mare volcanism revealed from spectral data

    Science.gov (United States)

    Kato, S.; Morota, T.; Yamaguchi, Y.; Watanabe, S.; Otake, H.; Ohtake, M.; Nimura, T.

    2016-12-01

    Lunar mare basalts provide insights into the composition and thermal history of the lunar mantle. According to crater counting analysis with remote sensing data, the ages of mare basalts suggest a first peak of magma activity at 3.2-3.8 Ga and a second peak at 2 Ga. In order to understand the mechanism for causing the second peak and its magma source, we reassess the correlation between the titanium contents and the eruption ages of mare basalt units using the compositional and chronological data updated by SELENE (Kaguya). In the Procellarum KREEP Terrane, where the latest mare basalt units are concentrated, an increase in the mean titanium content is observed in the Eratosthenian Period, as reported by previous studies. We found that, however, a rapid increase in mean titanium content occurred near 2.3 Ga. This result suggests that the magma source of the mare basalts changed at this particular age. Moreover, the high-titanium basaltic eruptions are correlated with the second peak in mare volcanism at 2 Ga. The latest mare volcanism may have been induced by a super-hot plume originating from the core-mantle boundary. In this study, to reveal the difference between the volcanic activities before and after 2.3 Ga, we developed the method to estimate the mineral components and elemental compositions of lunar mare basalts by using the Kaguya Spectral Profiler data. We will introduce the detail of the method and discuss about the difference between the mineral compositions of mare basalts before and after 2.3 Ga based on our preliminary results.

  20. Hubble Images Reveal Jupiter's Auroras

    Science.gov (United States)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.This image and other images and data

  1. Sources of atmospheric acidity

    International Nuclear Information System (INIS)

    Clarke, A.G.

    1992-01-01

    The emissions of acid gases from anthropogenic sources and their impact on the environment are the main concern of this book. However, that impact can only be assessed if all the naturally occurring sources of these gases are also known and can be quantified. Given the widely dispersed nature of the natural sources and the problems of measurement of trace species at low concentrations, often in remote regions, the quantification is a very difficult task. Nevertheless, considerable progress has been made over the last decade. In this chapter both man-made and natural sources of atmospheric acidity will be reviewed, but the emphasis will be placed not so much on the global balances as on the scale of the natural sources in relation to the man-made sources. This requires that the very uneven geographical distribution of emissions and the lifetime of individual chemical species be taken into account. The emissions considered are sulphur compounds, nitrogen compounds, chlorine compounds and organic acids. The anthropogenic sources discussed are the combustion of fossil fuels and certain industrial processes. Emissions data for anthropogenic sources are given for the United Kingdom, Europe, USA and globally. A list of 95 references is given. (Author)

  2. Measurement of atmospheric pollutants

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    Studies of simplified methods of determining various atmospheric pollutants were performed. Measurements with Kitagawa detecting tubes were made in front of Shibuya Station in Tokyo on October 27, 1973. The number of cars that passed the site was counted then the nitrogen dioxide, sulfur dioxide, hydrocarbons and carbon monoxide content was determined. The number of cars was about 7000-12,000 between 9 AM and 6 PM. The heaviest traffic occurred around 10 am, and the least traffic occurred around 1 pm. A simulation experiment of smoking was also performed. A simplified model of smoking indicated that the concentration of CO in the mouth is as high as 10,000-15,000 ppM. The simplified measurement of sulfur dioxide and nitrogen dioxide by the use of a small piece of an alkaline filter was also investigated. A photoelectric colorimeter gave an excellent demonstration of the pollution due to SO/sub 2/ and NO/sub 2/. A simplified determination of NO/sub 2/ by the Saltzman method was also performed.

  3. Revealing the programming process

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Caspersen, Michael Edelgaard

    2005-01-01

    One of the most important goals of an introductory programming course is that the students learn a systematic approach to the development of computer programs. Revealing the programming process is an important part of this; however, textbooks do not address the issue -- probably because...... the textbook medium is static and therefore ill-suited to expose the process of programming. We have found that process recordings in the form of captured narrated programming sessions are a simple, cheap, and efficient way of providing the revelation.We identify seven different elements of the programming...

  4. TypeScript revealed

    CERN Document Server

    Maharry, Dan

    2013-01-01

    TypeScript Revealed is a quick 100-page guide to Anders Hejlsberg's new take on JavaScript. With this brief, fast-paced introduction to TypeScript, .NET, Web and Windows 8 application developers who are already familiar with JavaScript will easily get up to speed with TypeScript and decide whether or not to start incorporating it into their own development. TypeScript is 'JavaScript for Application-scale development'; a superset of JavaScript that brings to it an additional object-oriented-like syntax familiar to .NET programmers that compiles down into simple, clean JavaScript that any browse

  5. Atmospheric carbon reduction by urban trees

    International Nuclear Information System (INIS)

    Nowak, D.J.

    1993-01-01

    Trees, because they sequester atmospheric carbon through their growth process and conserve energy in urban areas, have been suggested as one means to combat increasing levels of atmospheric carbon. Analysis of the urban forest in Oakland, California (21% tree cover), reveals a tree carbon storage level of 11·0 metric tons/hectare. Trees in the area of the 1991 fire in Oakland stored approximately 14,500 metric tons of carbon, 10% of the total amount stored by Oakland's urban forest. National urban forest carbon storage in the United States (28% tree cover) is estimated at between 350 and 750 million metric tons. Establishment of 10 million urban trees annually over the next 10 years is estimated to sequester and offset the production of 363 million metric tons of carbon over the next 50 years-less than 1% of the estimated carbon emissions in the United States over the same time period. Advantages and limitations of managing urban trees to reduce atmospheric carbon are discussed. 36 refs., 2 figs., 3 tabs

  6. Microwave Atmospheric-Pressure Sensor

    Science.gov (United States)

    Flower, D. A.; Peckham, G. E.; Bradford, W. J.

    1986-01-01

    Report describes tests of microwave pressure sounder (MPS) for use in satellite measurements of atmospheric pressure. MPS is multifrequency radar operating between 25 and 80 GHz. Determines signal absorption over vertical path through atmosphere by measuring strength of echoes from ocean surface. MPS operates with cloud cover, and suitable for use on current meteorological satellites.

  7. Geologic data on atmospheric history

    NARCIS (Netherlands)

    Rutten, M.G.

    1966-01-01

    Attention is focussed on the possible existence of an anoxygenic, primeval atmosphere and on the history of atmospheric O2 and CO2. For this purpose, geologic data can be divided into those on fossil remains, on biogenic deposits formed by early life, on “chemicofossils”, and on deposits formed

  8. Remote measurement of atmospheric pollutants

    Science.gov (United States)

    Allario, F.; Hoell, J.; Seals, R. K.

    1979-01-01

    The concentration and vertical distribution of atmospheric ammonia and ozone are remotely sensed, using dual-C02-laser multichannel infrared Heterodyne Spectrometer (1HS). Innovation makes atmospheric pollution measurements possible with nearly-quantum-noise-limited sensitivity and ultrafine spectral resolution.

  9. Pathlength distributions of atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Gaisser, T.K.; Stanev, Todor

    1999-01-01

    We discuss the distribution of the production heights of atmospheric neutrinos as a function of zenith angle and neutrino energy. The distributions can be used as the input for evaluation of neutrino propagation under various hypotheses for neutrino flavor oscillations. Their use may alter substantially the estimates of the oscillation parameters for almost horizontal atmospheric neutrinos.

  10. Criteria for controlled atmosphere chambers

    International Nuclear Information System (INIS)

    Robinson, J.N.

    1980-03-01

    The criteria for design, construction, and operation of controlled atmosphere chambers intended for service at ORNL are presented. Classification of chambers, materials for construction, design criteria, design, controlled atmosphere chamber systems, and operating procedures are presented. ORNL Safety Manual Procedure 2.1; ORNL Health Physics Procedure Manual Appendix A-7; and Design of Viewing Windows are included in 3 appendices

  11. Organic chemistry in Titan's atmosphere

    Science.gov (United States)

    Scattergood, T.

    1982-01-01

    Laboratory photochemical simulations and other types of chemical simulations are discussed. The chemistry of methane, which is the major known constituent of Titan's atmosphere was examined with stress on what can be learned from photochemistry and particle irradiation. The composition of dust that comprises the haze layer was determined. Isotope fractionation in planetary atmospheres is also discussed.

  12. Atmospheric Research 2012 Technical Highlights

    Science.gov (United States)

    Lau, William K -M.

    2013-01-01

    This annual report, as before, is intended for a broad audience. Our readers include colleagues within NASA, scientists outside the Agency, science graduate students, and members of the general public. Inside are descriptions of atmospheric research science highlights and summaries of our education and outreach accomplishments for calendar year 2012.The report covers research activities from the Mesoscale Atmospheric Processes Laboratory, the Climate and Radiation Laboratory, the Atmospheric Chemistry and Dynamics Laboratory, and the Wallops Field Support Office under the Office of Deputy Director for Atmospheres, Earth Sciences Division in the Sciences and Exploration Directorate of NASAs Goddard Space Flight Center. The overall mission of the office is advancing knowledge and understanding of the Earths atmosphere. Satellite missions, field campaigns, peer-reviewed publications, and successful proposals are essential to our continuing research.

  13. On the Atmospheric Correction of Antarctic Airborne Hyperspectral Data

    Directory of Open Access Journals (Sweden)

    Martin Black

    2014-05-01

    Full Text Available The first airborne hyperspectral campaign in the Antarctic Peninsula region was carried out by the British Antarctic Survey and partners in February 2011. This paper presents an insight into the applicability of currently available radiative transfer modelling and atmospheric correction techniques for processing airborne hyperspectral data in this unique coastal Antarctic environment. Results from the Atmospheric and Topographic Correction version 4 (ATCOR-4 package reveal absolute reflectance values somewhat in line with laboratory measured spectra, with Root Mean Square Error (RMSE values of 5% in the visible near infrared (0.4–1 µm and 8% in the shortwave infrared (1–2.5 µm. Residual noise remains present due to the absorption by atmospheric gases and aerosols, but certain parts of the spectrum match laboratory measured features very well. This study demonstrates that commercially available packages for carrying out atmospheric correction are capable of correcting airborne hyperspectral data in the challenging environment present in Antarctica. However, it is anticipated that future results from atmospheric correction could be improved by measuring in situ atmospheric data to generate atmospheric profiles and aerosol models, or with the use of multiple ground targets for calibration and validation.

  14. Exoplanetary Atmospheres-Chemistry, Formation Conditions, and Habitability.

    Science.gov (United States)

    Madhusudhan, Nikku; Agúndez, Marcelino; Moses, Julianne I; Hu, Yongyun

    2016-12-01

    Characterizing the atmospheres of extrasolar planets is the new frontier in exoplanetary science. The last two decades of exoplanet discoveries have revealed that exoplanets are very common and extremely diverse in their orbital and bulk properties. We now enter a new era as we begin to investigate the chemical diversity of exoplanets, their atmospheric and interior processes, and their formation conditions. Recent developments in the field have led to unprecedented advancements in our understanding of atmospheric chemistry of exoplanets and the implications for their formation conditions. We review these developments in the present work. We review in detail the theory of atmospheric chemistry in all classes of exoplanets discovered to date, from highly irradiated gas giants, ice giants, and super-Earths, to directly imaged giant planets at large orbital separations. We then review the observational detections of chemical species in exoplanetary atmospheres of these various types using different methods, including transit spectroscopy, Doppler spectroscopy, and direct imaging. In addition to chemical detections, we discuss the advances in determining chemical abundances in these atmospheres and how such abundances are being used to constrain exoplanetary formation conditions and migration mechanisms. Finally, we review recent theoretical work on the atmospheres of habitable exoplanets, followed by a discussion of future outlook of the field.

  15. Determination of the atmospheric neutrino fluxes from atmospheric neutrino data

    International Nuclear Information System (INIS)

    Gonzalez-Garcia, C.; Maltoni, M.; Rojo, J.

    2006-06-01

    The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based on the convolution of the primary cosmic ray spectrum with the expected yield of neutrinos per incident cosmic ray. In this work we present an alternative approach to the determination of the atmospheric neutrino fluxes based on the direct extraction from the experimental data on neutrino event rates. The extraction is achieved by means of a combination of artificial neural networks as interpolants and Monte Carlo methods for faithful error estimation. (author)

  16. Determination of the atmospheric neutrino fluxes from atmospheric neutrino data

    International Nuclear Information System (INIS)

    Gonzalez-Garcia, Concepcion; Maltoni, Michele; Rojo, Joan

    2006-01-01

    The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based on the convolution of the primary cosmic ray spectrum with the expected yield of neutrinos per incident cosmic ray. In this work we present an alternative approach to the determination of the atmospheric neutrino fluxes based on the direct extraction from the experimental data on neutrino event rates. The extraction is achieved by means of a combination of artificial neural networks as interpolants and Monte Carlo methods for faithful error estimation

  17. Atmospheric stability and atmospheric circulation in Athens, Greece

    International Nuclear Information System (INIS)

    Synodinou, B.M.; Petrakis, M.; Kassomenos, P.; Lykoudis, S.

    1996-01-01

    In the evaluation and study of atmospheric pollution reference is always made to the stability criteria. These criteria, usually represented as functions of different meteorological data such as wind speed and direction, temperature, solar radiation, etc., play a very important role in the investigation of different parameters that affect the build up of pollution episodes mainly in urban areas. In this paper an attempt is made to evaluate the atmospheric stability criteria based on measurements obtained from two locations in and nearby Athens. The atmospheric stability is then examined along with the other meteorological parameters

  18. Atmospheric Seasonality as an Exoplanet Biosignature

    Science.gov (United States)

    Olson, Stephanie L.; Schwieterman, Edward W.; Reinhard, Christopher T.; Ridgwell, Andy; Kane, Stephen R.; Meadows, Victoria S.; Lyons, Timothy W.

    2018-05-01

    Current investigations of exoplanet biosignatures have focused on static evidence of life, such as the presence of biogenic gases like O2 or CH4. However, the expected diversity of terrestrial planet atmospheres and the likelihood of both “false positives” and “false negatives” for conventional biosignatures motivate exploration of additional life detection strategies, including time-varying signals. Seasonal variation in atmospheric composition is a biologically modulated phenomenon on Earth that may occur elsewhere because it arises naturally from the interplay between the biosphere and time-variable insolation. The search for seasonality as a biosignature would avoid many assumptions about specific metabolisms and provide an opportunity to directly quantify biological fluxes—allowing us to characterize, rather than simply recognize, biospheres on exoplanets. Despite this potential, there have been no comprehensive studies of seasonality as an exoplanet biosignature. Here, we provide a foundation for further studies by reviewing both biological and abiological controls on the magnitude and detectability of seasonality of atmospheric CO2, CH4, O2, and O3 on Earth. We also consider an example of an inhabited world for which atmospheric seasonality may be the most notable expression of its biosphere. We show that life on a low O2 planet like the weakly oxygenated mid-Proterozoic Earth could be fingerprinted by seasonal variation in O3 as revealed in its UV Hartley–Huggins bands. This example highlights the need for UV capabilities in future direct-imaging telescope missions (e.g., LUVOIR/HabEx) and illustrates the diagnostic importance of studying temporal biosignatures for exoplanet life detection/characterization.

  19. Chemistry of plutonium revealed

    International Nuclear Information System (INIS)

    Connick, R.E.

    1992-01-01

    In 1941 one goal of the Manhattan Project was to unravel the chemistry of the synthetic element plutonium as rapidly as possible. In this paper the work carried out at Berkeley from the spring of 1942 to the summer of 1945 is described briefly. The aqueous chemistry of plutonium is quite remarkable. Important insights were obtained from tracer experiments, but the full complexity was not revealed until macroscopic amounts (milligrams) became available. Because processes for separation from fission products were based on aqueous solutions, such solution chemistry was emphasized, particularly precipitation and oxidation-reduction behavior. The latter turned out to be unusually intricate when it was discovered that two more oxidation states existed in aqueous solution than had previously been suspected. Further, an equilibrium was rapidly established among the four aqueous oxidation states, while at the same time any three were not in equilibrium. These and other observations made while doing a crash study of a previously unknown element are reported

  20. Android Emotions Revealed

    DEFF Research Database (Denmark)

    Vlachos, Evgenios; Schärfe, Henrik

    2012-01-01

    This work presents a method for designing facial interfaces for sociable android robots with respect to the fundamental rules of human affect expression. Extending the work of Paul Ekman towards a robotic direction, we follow the judgment-based approach for evaluating facial expressions to test...... findings are based on the results derived from a number of judgments, and suggest that before programming the facial expressions of a Geminoid, the Original should pass through the proposed procedure. According to our recommendations, the facial expressions of an android should be tested by judges, even...... in which case an android robot like the Geminoid|DK –a duplicate of an Original person- reveals emotions convincingly; when following an empirical perspective, or when following a theoretical one. The methodology includes the processes of acquiring the empirical data, and gathering feedback on them. Our...

  1. Radiation transfer and stellar atmospheres

    Science.gov (United States)

    Swihart, T. L.

    This is a revised and expanded version of the author's Basic Physics of Stellar Atmospheres, published in 1971. The equation of transfer is considered, taking into account the intensity and derived quantities, the absorption coefficient, the emission coefficient, the source function, and special integrals for plane media. The gray atmosphere is discussed along with the nongray atmosphere, and aspects of line formation. Topics related to polarization are explored, giving attention to pure polarized radiation, general polarized radiation, transfer in a magnetic plasma, and Rayleigh scattering and the sunlit sky. Physical and astronomical constants, and a number of problems related to the subjects of the book are presented in an appendix.

  2. Atmospheres of the terrestrial planets

    International Nuclear Information System (INIS)

    Kivelson, M.G.; Schubert, G.

    1986-01-01

    Properties of the planets are identified - such as size, spin rate, and distance from the sun - that are important in understanding the characteristics of their atmospheres. Venus, earth and Mars have surface-temperature differences only partly explained by the decrease of solar radiation flux with distance from the sun. More significant effects arise from the variations in the degree to which the atmospheres act as absorbers of planetary thermal reradiation. Atmospheric circulation on a global scale also varies markedly among the three planets. 5 references

  3. Hydrodynamics of oceans and atmospheres

    CERN Document Server

    Eckart, Carl

    1960-01-01

    Hydrodynamics of Oceans and Atmospheres is a systematic account of the hydrodynamics of oceans and atmospheres. Topics covered range from the thermodynamic functions of an ideal gas and the thermodynamic coefficients for water to steady motions, the isothermal atmosphere, the thermocline, and the thermosphere. Perturbation equations, field equations, residual equations, and a general theory of rays are also presented. This book is comprised of 17 chapters and begins with an introduction to the basic equations and their solutions, with the aim of illustrating the laws of dynamics. The nonlinear

  4. Atmospheric Entry Studies for Uranus

    Science.gov (United States)

    Agrawal, P.; Allen, G. A.; Hwang, H. H.; Marley, M. S.; McGuire, M. K.; Garcia, J. A.; Sklyanskiy, E.; Huynh, L. C.; Moses, R. W.

    2014-07-01

    To better understand the technology requirements for Uranus atmospheric entry probe, Entry Vehicle Technology project funded an internal study with a multidisciplinary team from NASA Ames, Langley and JPL. The results of this study are communicated.

  5. The bibliometrics of atmospheric environment

    Science.gov (United States)

    Brimblecombe, Peter; Grossi, Carlota M.

    Bibliometric analysis is an important tool in the management of a journal. SCOPUS output is used to assess the increase in the quantity of material in Atmospheric Environment and stylistic changes in the way authors choose words and punctuation in titles and assemble their reference lists. Citation analysis is used to consider the impact factor of the journal, but perhaps more importantly the way in which it reflects the importance authors give to papers published in Atmospheric Environment. The impact factor of Atmospheric Environment (2.549 for 2007) from the Journal Citation Reports suggests it performs well within the atmospheric sciences, but it conceals the long term value authors place on papers appearing in the journal. Reference lists show that a fifth come through citing papers more than a decade old.

  6. Atmospheric pressure plasma vapour coatings

    NARCIS (Netherlands)

    Sanden, van de M.C.M.; Starostine, S.; Premkumar, P.A.; Creatore, M.; Vries, de H.W.; Kondruweit, S.; Szyszka, B.; Pütz, J.

    2010-01-01

    The dielectric barrier discharge (DBD) is recognized as a promising tool of thin films deposition on various substrates at atmospheric pressure. Emerging applications including encapsulation of flexible solar cells and flexible displays require large scale low costs production cif transparent

  7. (Chemistry of the global atmosphere)

    Energy Technology Data Exchange (ETDEWEB)

    Marland, G.

    1990-09-27

    The traveler attended the conference The Chemistry of the Global Atmosphere,'' and presented a paper on the anthropogenic emission of carbon dioxide (CO{sub 2}) to the atmosphere. The conference included meetings of the International Global Atmospheric Chemistry (IGAC) programme, a core project of the International Geosphere/Biosphere Programme (IGBP) and the traveler participated in meetings on the IGAC project Development of Global Emissions Inventories'' and agreed to coordinate the working group on CO{sub 2}. Papers presented at the conference focused on the latest developments in analytical methods, modeling and understanding of atmospheric CO{sub 2}, CO, CH{sub 4}, N{sub 2}O, SO{sub 2}, NO{sub x}, NMHCs, CFCs, and aerosols.

  8. Exploring the Atmosphere with Lidars

    Indian Academy of Sciences (India)

    the source is beyond the control of the observer, e.g. radiometer, photometer ... of the atmosphere, environmental monitoring, measurement of air quality ... able for the development of mobile systems for vehicles, aircraft and spacecraft ...

  9. Atmospheric Research 2014 Technical Highlights

    Science.gov (United States)

    Platnick, Steven

    2015-01-01

    Atmospheric research in the Earth Sciences Division (610) consists of research and technology development programs dedicated to advancing knowledge and understanding of the atmosphere and its interaction with the climate of Earth. The Division's goals are to improve understanding of the dynamics and physical properties of precipitation, clouds, and aerosols; atmospheric chemistry, including the role of natural and anthropogenic trace species on the ozone balance in the stratosphere and the troposphere; and radiative properties of Earth's atmosphere and the influence of solar variability on the Earth's climate. Major research activities are carried out in the Mesoscale Atmospheric Processes Laboratory, the Climate and Radiation Laboratory, the Atmospheric Chemistry and Dynamics Laboratory, and the Wallops Field Support Office. The overall scope of the research covers an end-to-end process, starting with the identification of scientific problems, leading to observation requirements for remote-sensing platforms, technology and retrieval algorithm development; followed by flight projects and satellite missions; and eventually, resulting in data processing, analyses of measurements, and dissemination from flight projects and missions. Instrument scientists conceive, design, develop, and implement ultraviolet, infrared, optical, radar, laser, and lidar technology to remotely sense the atmosphere. Members of the various Laboratories conduct field measurements for satellite sensor calibration and data validation, and carry out numerous modeling activities. These modeling activities include climate model simulations, modeling the chemistry and transport of trace species on regional-to-global scales, cloud resolving models, and developing the next-generation Earth system models. Satellite missions, field campaigns, peer-reviewed publications, and successful proposals are essential at every stage of the research process to meeting our goals and maintaining leadership of the

  10. Uranus atmospheric dynamics and circulation

    Science.gov (United States)

    Allison, Michael; Beebe, Reta F.; Conrath, Barney J.; Hinson, David P.; Ingersoll, Andrew P.

    1991-01-01

    The observations, models, and theories relevant to the atmospheric dynamics and meteorology of Uranus are discussed. The available models for the large-scale heat transport and atmospheric dynamics as well as diagnostic interpretations of the Voyager data are reviewed. Some pertinent ideas and questions regarding the global circulation balance are considered, partly in comparison with other planetary atmospheres. The available data indicate atmospheric rotation at midlatitudes nearly 200 m/s faster than that of the planetary magnetic field. Analysis of the dynamical deformation of the shape and size of isobaric surfaces measured by the Voyager radio-occultation experiment suggests a subrotating equator at comparable altitudes. Infrared temperature retrievals above the cloud deck indicate a smaller equator-to-pole contrast than expected for purely radiative-convective equilibrium, but show local variations implying a latitudinally correlated decrease with altitude in the cloud-tracked wind.

  11. Atmospheres in a Test Tube

    Science.gov (United States)

    Claudi, R.; Erculiani, M. S.; Giro, E.; D'Alessandro, M.; Galletta, G.

    2013-09-01

    The "Atmosphere in a Test Tube" project is a laboratory experiment that will be able to reproduce condition of extreme environments by means of a simulator. These conditions span from those existing inside some parts of the human body to combinations of temperatures, pressures, irradiation and atmospheric gases present on other planets. In this latter case the experiments to be performed will be useful as preliminary tests for both simulation of atmosphere of exoplanets and Solar System planets and Astrobiology experiments that should be performed by planetary landers or by instruments to be launched in the next years. In particular at INAF Astronomical Observatory of Padova Laboratory we are approaching the characterization of extrasolar planet atmospheres taking advantage by innovative laboratory experiments with a particular focus on low mass Neptunes and Super earths and low mass M dwarfs primaries.

  12. Atmospheric science and power production

    Energy Technology Data Exchange (ETDEWEB)

    Randerson, D. (ed.)

    1984-07-01

    This is the third in a series of scientific publications sponsored by the US Atomic Energy Commission and the two later organizations, the US Energy Research and Development Adminstration, and the US Department of Energy. The first book, Meteorology and Atomic Energy, was published in 1955; the second, in 1968. The present volume is designed to update and to expand upon many of the important concepts presented previously. However, the present edition draws heavily on recent contributions made by atmospheric science to the analysis of air quality and on results originating from research conducted and completed in the 1970s. Special emphasis is placed on how atmospheric science can contribute to solving problems relating to the fate of combustion products released into the atmosphere. The framework of this book is built around the concept of air-quality modeling. Fundamentals are addressed first to equip the reader with basic background information and to focus on available meteorological instrumentation and to emphasize the importance of data management procedures. Atmospheric physics and field experiments are described in detail to provide an overview of atmospheric boundary layer processes, of how air flows around obstacles, and of the mechanism of plume rise. Atmospheric chemistry and removal processes are also detailed to provide fundamental knowledge on how gases and particulate matter can be transformed while in the atmosphere and how they can be removed from the atmosphere. The book closes with a review of how air-quality models are being applied to solve a wide variety of problems. Separate analytics have been prepared for each chapter.

  13. Radionuclide dispersion in the atmosphere

    International Nuclear Information System (INIS)

    Moura Neto, C. de; Amorim, E.S. do; Panetta, J.

    1979-05-01

    The instantaneous liberation of radionuclides in the atmosphere is studied in three dimensions, according to the formalism of the diffusion theory. The analytical solution, expose to gravitational and an atmospherical effects, is combined with the discretization of space and time in the calculation of levels of exposure. A typical inventory (for a PWR) was considered in the calculation of immersion doses, and the results permitted a comparative analysis among the different existing models. (Author) [pt

  14. LIDAR and atmosphere remote sensing

    CSIR Research Space (South Africa)

    Venkataraman, S

    2008-05-01

    Full Text Available using state of the art Light Detection And Ranging (LiDAR) instrumentation and other active and passive remote sensing tools. First “Lidar Field Campaign” • 2-day measurement campaign at University of Pretoria • First 23-hour continuous measurement... head2rightCirrus cloud morphology and dynamics. Atmospheric Research in Southern Africa and Indian Ocean (ARSAIO) Slide 24 © CSIR 2008 www.csir.co.za Middle atmosphere dynamics and thermal structure: comparative studies from...

  15. Atmospheric Research 2016 Technical Highlights

    Science.gov (United States)

    Platnick, Steven

    2017-01-01

    Atmospheric research in the Earth Sciences Division (610) consists of research and technology development programs dedicated to advancing knowledge and understanding of the atmosphere and its interaction with the climate of Earth. The Divisions goals are to improve understanding of the dynamics and physical properties of precipitation, clouds, and aerosols; atmospheric chemistry, including the role of natural and anthropogenic trace species on the ozone balance in the stratosphere and the troposphere; and radiative properties of Earth's atmosphere and the influence of solar variability on the Earth's climate. Major research activities are carried out in the Mesoscale Atmospheric Processes Laboratory, the Climate and Radiation Laboratory, the Atmospheric Chemistry and Dynamics Laboratory, and the Wallops Field Support Office. The overall scope of the research covers an end-to-end process, starting with the identification of scientific problems, leading to observation requirements for remote-sensing platforms, technology and retrieval algorithm development; followed by flight projects and satellite missions; and eventually, resulting in data processing, analyses of measurements, and dissemination from flight projects and missions. Instrument scientists conceive, design, develop, and implement ultraviolet, infrared, optical, radar, laser, and lidar technology to remotely sense the atmosphere. Members of the various laboratories conduct field measurements for satellite sensor calibration and data validation, and carry out numerous modeling activities. These modeling activities include climate model simulations, modeling the chemistry and transport of trace species on regional-to-global scales, cloud resolving models, and developing the next-generation Earth system models. Satellite missions, field campaigns, peer-reviewed publications, and successful proposals are essential at every stage of the research process to meeting our goals and maintaining leadership of the

  16. Clouds in the Martian Atmosphere

    Science.gov (United States)

    Määttänen, Anni; Montmessin, Franck

    2018-01-01

    Although resembling an extremely dry desert, planet Mars hosts clouds in its atmosphere. Every day somewhere on the planet a part of the tiny amount of water vapor held by the atmosphere can condense as ice crystals to form cirrus-type clouds. The existence of water ice clouds has been known for a long time, and they have been studied for decades, leading to the establishment of a well-known climatology and understanding of their formation and properties. Despite their thinness, they have a clear impact on the atmospheric temperatures, thus affecting the Martian climate. Another, more exotic type of clouds forms as well on Mars. The atmospheric temperatures can plunge to such frigid values that the major gaseous component of the atmosphere, CO2, condenses as ice crystals. These clouds form in the cold polar night where they also contribute to the formation of the CO2 ice polar cap, and also in the mesosphere at very high altitudes, near the edge of space, analogously to the noctilucent clouds on Earth. The mesospheric clouds are a fairly recent discovery and have put our understanding of the Martian atmosphere to a test. On Mars, cloud crystals form on ice nuclei, mostly provided by the omnipresent dust. Thus, the clouds link the three major climatic cycles: those of the two major volatiles, H2O and CO2; and that of dust, which is a major climatic agent itself.

  17. Illusion and reality in the atmospheres of exoplanets

    Science.gov (United States)

    Deming, L. Drake; Seager, Sara

    2017-01-01

    The atmospheres of exoplanets reveal all their properties beyond mass, radius, and orbit. Based on bulk densities, we know that exoplanets larger than 1.5 Earth radii must have gaseous envelopes and, hence, atmospheres. We discuss contemporary techniques for characterization of exoplanetary atmospheres. The measurements are difficult, because—even in current favorable cases—the signals can be as small as 0.001% of the host star's flux. Consequently, some early results have been illusory and not confirmed by subsequent investigations. Prominent illusions to date include polarized scattered light, temperature inversions, and the existence of carbon planets. The field moves from the first tentative and often incorrect conclusions, converging to the reality of exoplanetary atmospheres. That reality is revealed using transits for close-in exoplanets and direct imaging for young or massive exoplanets in distant orbits. Several atomic and molecular constituents have now been robustly detected in exoplanets as small as Neptune. In our current observations, the effects of clouds and haze appear ubiquitous. Topics at the current frontier include the measurement of heavy element abundances in giant planets, detection of carbon-based molecules, measurement of atmospheric temperature profiles, definition of heat circulation efficiencies for tidally locked planets, and the push to detect and characterize the atmospheres of super-Earths. Future observatories for this quest include the James Webb Space Telescope and the new generation of extremely large telescopes on the ground. On a more distant horizon, NASA's study concepts for the Habitable Exoplanet Imaging Mission (HabEx) and the Large UV/Optical/Infrared Surveyor (LUVOIR) missions could extend the study of exoplanetary atmospheres to true twins of Earth.

  18. Improving InSAR geodesy using Global Atmospheric Models

    Science.gov (United States)

    Jolivet, Romain; Agram, Piyush Shanker; Lin, Nina Y.; Simons, Mark; Doin, Marie-Pierre; Peltzer, Gilles; Li, Zhenghong

    2014-03-01

    Spatial and temporal variations of pressure, temperature, and water vapor content in the atmosphere introduce significant confounding delays in interferometric synthetic aperture radar (InSAR) observations of ground deformation and bias estimates of regional strain rates. Producing robust estimates of tropospheric delays remains one of the key challenges in increasing the accuracy of ground deformation measurements using InSAR. Recent studies revealed the efficiency of global atmospheric reanalysis to mitigate the impact of tropospheric delays, motivating further exploration of their potential. Here we explore the effectiveness of these models in several geographic and tectonic settings on both single interferograms and time series analysis products. Both hydrostatic and wet contributions to the phase delay are important to account for. We validate these path delay corrections by comparing with estimates of vertically integrated atmospheric water vapor content derived from the passive multispectral imager Medium-Resolution Imaging Spectrometer, onboard the Envisat satellite. Generally, the performance of the prediction depends on the vigor of atmospheric turbulence. We discuss (1) how separating atmospheric and orbital contributions allows one to better measure long-wavelength deformation and (2) how atmospheric delays affect measurements of surface deformation following earthquakes, and (3) how such a method allows us to reduce biases in multiyear strain rate estimates by reducing the influence of unevenly sampled seasonal oscillations of the tropospheric delay.

  19. Atmosphere-Ionosphere Electrodynamic Coupling

    Science.gov (United States)

    Sorokin, V. M.; Chmyrev, V. M.

    Numerous phenomena that occur in the mesosphere, ionosphere, and the magnetosphere of the Earth are caused by the sources located in the lower atmosphere and on the ground. We describe the effects produced by lightning activity and by ground-based transmitters operated in high frequency (HF) and very low frequency (VLF) ranges. Among these phenomena are the ionosphere heating and the formation of plasma density inhomogeneities, the excitation of gamma ray bursts and atmospheric emissions in different spectral bands, the generation of ULF/ELF/VLF electromagnetic waves and plasma turbulence in the ionosphere, the stimulation of radiation belt electron precipitations and the acceleration of ions in the upper ionosphere. The most interesting results of experimental and theoretical studies of these phenomena are discussed below. The ionosphere is subject to the action of the conductive electric current flowing in the atmosphere-ionosphere circuit. We present a physical model of DC electric field and current formation in this circuit. The key element of this model is an external current, which is formed with the occurrence of convective upward transport of charged aerosols and their gravitational sedimentation in the atmosphere. An increase in the level of atmospheric radioactivity results in the appearance of additional ionization and change of electrical conductivity. Variation of conductivity and external current in the lower atmosphere leads to perturbation of the electric current flowing in the global atmosphere-ionosphere circuit and to the associated DC electric field perturbation both on the Earth's surface and in the ionosphere. Description of these processes and some results of the electric field and current calculations are presented below. The seismic-induced electric field perturbations produce noticeable effects in the ionosphere by generating the electromagnetic field and plasma disturbances. We describe the generation mechanisms of such experimentally

  20. Problems in global atmospheric chemistry

    Science.gov (United States)

    Crutzen, Paul J.

    1993-02-01

    The chemistry of the atmosphere is substantially influenced by a wide range of chemical processes which are primarily driven by the action of ultraviolet radiation of wavelengths shorter than 320 nm (UV-B) on ozone and water vapor. This leads to the formation of hydroxyl (OH) radicals which, despite very low tropospheric concentrations, remove most gases that are emitted into the atmosphere by natural and anthropogenic processes. Therefore, although only about 10% of all atmospheric ozone is located in the troposphere, through the formation of OH, it determines the oxidation efficiency of the atmosphere and is, therefore, of the utmost importance for maintaining its chemical composition. Due to a variety of human activities, especially through increasing emissions of CH4, CO, and NOx, the concentrations of tropospheric ozone and hydroxyl are expected to be increasing in polluted and decreasing in clean tropospheric environments. Altogether, this may be leading to an overall decrease in the oxidation efficiency of the atmosphere, contributing to a gradual buildup of several longlived trace gases that are primarily removed by reaction with OH. In the stratosphere, especially due to catalytic reactions of chlorine-containing gases of industrial origin, ozone is being depleted, most drastically noted during the early spring months over Antarctica. Because ozone is the only atmospheric constituent that can significantly absorb solar radiation in the wavelength region 240 - 320 nm, this loss of ozone enhances the penetration of biologically harmful UV-B radiation to the earth's surface with ensuing negative consequences for the biosphere. Several of the aforementioned chemically active trace gases with growing trends in the atmosphere are also efficient greenhouse gases. Together they can exert a warming effect on the earth's climate about equal to that of carbon dioxide.

  1. Organic chemistry in the atmosphere. [laboratory modeling of Titan atmosphere

    Science.gov (United States)

    Sagan, C.

    1974-01-01

    The existence of an at least moderately complex organic chemistry on Titan is stipulated based on clear evidence of methane, and at least presumptive evidence of hydrogen in its atmosphere. The ratio of methane to hydrogen is the highest of any atmosphere in the solar system. Irradiation of hydrogen/methane mixtures produces aromatic and aliphatic hydrocarbons. A very reasonable hypothesis assumes that the red cloud cover of Titan is made of organic chemicals. Two-carbon hydrocarbons experimentally produced from irradiated mixtures of methane, ammonia, water, and hydrogen bear out the possible organic chemistry of the Titanian environment.

  2. Atmospheric Chemistry Over Southern Africa

    Science.gov (United States)

    Gatebe, Charles K.; Levy, Robert C.; Thompson, Anne M.

    2011-01-01

    During the southern African dry season, regional haze from mixed industrial pollution, biomass burning aerosol and gases from domestic and grassland fires, and biogenic sources from plants and soils is worsened by a semi-permanent atmosphere gyre over the subcontinent. These factors were a driver of several major international field campaigns in the 1990s and early 2000s, and attracted many scientists to the region. Some researchers were interested in understanding fundamental processes governing chemistry of the atmosphere and interaction with climate change. Others found favorable conditions for evaluating satellite-derived measurements of atmospheric properties and a changing land surface. With that background in mind a workshop on atmospheric chemistry was held in South Africa. Sponsored by the International Commission for Atmospheric Chemistry and Global Pollution (ICACGP; http://www.icacgp.org/), the workshop received generous support from the South African power utility, Eskom, and the Climatology Research Group of the University of the Witwatersrand, Johannesburg, South Africa. The purpose of the workshop was to review some earlier findings as well as more recent findings on southern African climate vulnerability, chemical changes due to urbanization, land-use modification, and how these factors interact. Originally proposed by John Burrows, president of ICACGP, the workshop was the first ICACGP regional workshop to study the interaction of air pollution with global chemical and climate change. Organized locally by the University of the Witwatersrand, the workshop attracted more than 60 delegates from South Africa, Mozambique, Botswana, Zimbabwe, France, Germany, Canada, and the United States. More than 30 presentations were given, exploring both retrospective and prospective aspects of the science. In several talks, attention was focused on southern African chemistry, atmospheric pollution monitoring, and climate processes as they were studied in the field

  3. Hydrodynamic escape from planetary atmospheres

    Science.gov (United States)

    Tian, Feng

    Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Due to the existence of a singularity point near the transonic point, it is difficult to find transonic steady state solutions by solving the time-independent hydrodynamic equations. In addition to that, most previous works assume that all energy driving the escape flow is deposited in one narrow layer. This assumption not only results in less accurate solutions to the hydrodynamic escape problem, but also makes it difficult to include other chemical and physical processes in the hydrodynamic escape models. In this work, a numerical model describing the transonic hydrodynamic escape from planetary atmospheres is developed. A robust solution technique is used to solve the time dependent hydrodynamic equations. The method has been validated in an isothermal atmosphere where an analytical solution is available. The hydrodynamic model is applied to 3 cases: hydrogen escape from small orbit extrasolar planets, hydrogen escape from a hydrogen rich early Earth's atmosphere, and nitrogen/methane escape from Pluto's atmosphere. Results of simulations on extrasolar planets are in good agreement with the observations of the transiting extrasolar planet HD209458b. Hydrodynamic escape of hydrogen from other hypothetical close-in extrasolar planets are simulated and the influence of hydrogen escape on the long-term evolution of these extrasolar planets are discussed. Simulations on early Earth suggest that hydrodynamic escape of hydrogen from a hydrogen rich early Earth's atmosphere is about two orders magnitude slower than the diffusion limited escape rate. A hydrogen rich early Earth's atmosphere could have been maintained by the balance between the hydrogen escape and the supply of hydrogen into the atmosphere by volcanic outgassing. Origin of life may have occurred in the organic soup ocean created by the efficient formation of prebiotic molecules in the hydrogen rich early

  4. Lord Kelvin's atmospheric electricity measurements

    Science.gov (United States)

    Aplin, Karen; Harrison, R. Giles; Trainer, Matthew; Hough, James

    2013-04-01

    Lord Kelvin (William Thomson), one of the greatest Victorian scientists, made a substantial but little-recognised contribution to geophysics through his work on atmospheric electricity. He developed sensitive instrumentation for measuring the atmospheric electric field, including invention of a portable electrometer, which made mobile measurements possible for the first time. Kelvin's measurements of the atmospheric electric field in 1859, made during development of the portable electrometer, can be used to deduce the substantial levels of particulate pollution blown over the Scottish island of Arran from the industrial mainland. Kelvin was also testing the electrometer during the largest solar flare ever recorded, the "Carrington event" in the late summer of 1859. Subsequently, Lord Kelvin also developed a water dropper sensor, and employed photographic techniques for "incessant recording" of the atmospheric electric field, which led to the long series of measurements recorded at UK observatories for the remainder of the 19th and much of the 20th century. These data sets have been valuable in both studies of historical pollution and cosmic ray effects on atmospheric processes.

  5. Atmosphere in a Test Tube

    Science.gov (United States)

    Claudi, R.; Pace, E.; Ciaravella, A.; Micela, G.; Piccioni, G.; Billi, D.; Cestelli Guidi, M.; Coccola, L.; Erculiani, M. S.; Fedel, M.; Galletta, G.; Giro, E.; La Rocca, N.; Morosinotto, T.; Poletto, L.; Schierano, D.; Stefani, S.

    The ancestor philosophers' dream of thousand of new world is finally realised: more than 1800 extrasolar planets have been discovered in the neighborhood of our Sun. Most of them are very different from those we used to know in our Solar System. Others orbit the Habitable Zone (HZ) of their parent stars. Space missions, as JWST and the very recently proposed ARIEL, or ground based instruments, like SPHERE@VLT, GPI@GEMINI and EPICS@ELT, have been proposed and built to measure the atmospheric transmission, reflection and emission spectra over a wide wavelength range of these new worlds. In order to interpret the spectra coming out by this new instrumentation, it is important to know in detail the optical characteristics of gases in the typical physical conditions of the planetary atmospheres and how those characteristics could be affected by radiation driven photochemical and bio-chemical reaction. Insights in this direction can be achieved from laboratory studies of simulated planetary atmosphere of different pressure and temperature conditions under the effects of radiation sources, used as proxies of different bands of the stellar emission. ''Atmosphere in a Test Tube'' is a collaboration among several Italian astronomical, biological and engineering institutes in order to share their experiencece in performing laboratory experiments on several items concerning extrasolar planet atmospheres.

  6. Examining Model Atmospheric Particles Inside and Out

    Science.gov (United States)

    Wingen, L. M.; Zhao, Y.; Fairhurst, M. C.; Perraud, V. M.; Ezell, M. J.; Finlayson-Pitts, B. J.

    2017-12-01

    Atmospheric particles scatter incoming solar radiation and act as cloud condensation nuclei (CCN), thereby directly and indirectly affecting the earth's radiative balance and reducing visibility. These atmospheric particles may not be uniform in composition. Differences in the composition of a particle's outer surface from its core can arise during particle growth, (photo)chemical aging, and exchange of species with the gas phase. The nature of the surface on a molecular level is expected to impact growth mechanisms as well as their ability to act as CCN. Model laboratory particle systems are explored using direct analysis in real time-mass spectrometry (DART-MS), which is sensitive to surface composition, and contrasted with average composition measurements using high resolution, time-of-flight aerosol mass spectrometry (HR-ToF-AMS). Results include studies of the heterogeneous reactions of amines with solid dicarboxylic acid particles, which are shown to generate aminium dicarboxylate salts at the particle surface, leaving an unreacted core. Combination of both mass spectrometric techniques reveals a trend in reactivity of C3-C7 dicarboxylic acids with amines and allows calculation of the DART probe depth into the particles. The results of studies on additional model systems that are currently being explored will also be reported.

  7. Reassessing the atmospheric oxidation mechanism of toluene

    Science.gov (United States)

    Ji, Yuemeng; Zhao, Jun; Terazono, Hajime; Misawa, Kentaro; Levitt, Nicholas P.; Li, Yixin; Lin, Yun; Peng, Jianfei; Wang, Yuan; Duan, Lian; Pan, Bowen; Zhang, Fang; Feng, Xidan; An, Taicheng; Marrero-Ortiz, Wilmarie; Secrest, Jeremiah; Zhang, Annie L.; Shibuya, Kazuhiko; Molina, Mario J.; Zhang, Renyi

    2017-08-01

    Photochemical oxidation of aromatic hydrocarbons leads to tropospheric ozone and secondary organic aerosol (SOA) formation, with profound implications for air quality, human health, and climate. Toluene is the most abundant aromatic compound under urban environments, but its detailed chemical oxidation mechanism remains uncertain. From combined laboratory experiments and quantum chemical calculations, we show a toluene oxidation mechanism that is different from the one adopted in current atmospheric models. Our experimental work indicates a larger-than-expected branching ratio for cresols, but a negligible formation of ring-opening products (e.g., methylglyoxal). Quantum chemical calculations also demonstrate that cresols are much more stable than their corresponding peroxy radicals, and, for the most favorable OH (ortho) addition, the pathway of H extraction by O2 to form the cresol proceeds with a smaller barrier than O2 addition to form the peroxy radical. Our results reveal that phenolic (rather than peroxy radical) formation represents the dominant pathway for toluene oxidation, highlighting the necessity to reassess its role in ozone and SOA formation in the atmosphere.

  8. Atmospheric multidecadal variations in the North Atlantic realm: proxy data, observations, and atmospheric circulation model studies

    Directory of Open Access Journals (Sweden)

    K. Grosfeld

    2007-01-01

    Full Text Available We investigate the spatial and temporal characteristics of multidecadal climate variability in the North Atlantic realm, using observational data, proxy data and model results. The dominant pattern of multidecadal variability of SST depicts a monopolar structure in the North Atlantic during the instrumental period with cold (warm phases during 1900–1925 and 1970–1990 (1870–1890 and 1940–1960. Two atmospheric general circulation models of different complexity forced with global SST over the last century show SLP anomaly patterns from the warm and cold phases of the North Atlantic similar to the corresponding observed patterns. The analysis of a sediment core from Cariaco Basin, a coral record from the northern Red Sea, and a long-term sea level pressure (SLP reconstruction reveals that the multidecadal mode of the atmospheric circulation characterizes climate variability also in the pre-industrial era. The analyses of SLP reconstruction and proxy data depict a persistent atmospheric mode at least over the last 300 years, where SLP shows a dipolar structure in response to monopolar North Atlantic SST, in a similar way as the models' responses do. The combined analysis of observational and proxy data with model experiments provides an understanding of multidecadal climate modes during the late Holocene. The related patterns are useful for the interpretation of proxy data in the North Atlantic realm.

  9. Interaction of Titan's atmosphere with Saturn's magnetosphere

    International Nuclear Information System (INIS)

    Hartle, R.E.

    1985-01-01

    The Voyager 1 measurements made during the Titan flyby reveal that Saturn's rotating magnetospheric plasma interacts directly with Titan's neutral atmosphere and ionosphere. This results from the lack of an intrinsic magnetic field at Titan. The interaction induces a magnetosphere which deflects the flowing plasma around Titan and forms a plasma wake downstream. Within the tail of the induced magnetosphere, ions of ionospheric origin flow away from Titan. Just outside Titan's magnetosphere, a substantial ion-exosphere forms from an extensive hydrogen-nitrogen exosphere. The exospheric ions are picked up and carried downstream into the wake by the plasma flowing around Titan. Mass loading produced by the addition of exospheric ions slows the wake plasma down considerably in the vicinity of the magnetopause. 36 references

  10. GCM simulations of cold dry Snowball Earth atmospheres

    Science.gov (United States)

    Voigt, A.; Held, I.; Marotzke, J.

    2009-12-01

    We use the full-physics atmospheric general circulation model ECHAM5 to investigate cold and virtually dry Snowball Earth atmospheres. These result from specifying sea ice as the surface boundary condition everywhere, corresponding to a frozen aquaplanet, while keeping total solar irradiance at its present-day value of 1365 Wm-2 and setting atmospheric carbon dioxide to 300 ppmv. Here, we present four simulations corresponding to the four possible combinations of enabled or disabled diurnal and seasonal cycles. The aim of this study is twofold. First, we focus on the zonal-mean circulation of Snowball Earth atmospheres, which, due to missing moisture, might constitute an ideal though yet unexplored testbed for theories of atmospheric dynamics. Second, we investigate tropical surface temperatures with an emphasis on the impact of the diurnal and seasonal cycles. This will indicate whether the presence of the diurnal or seasonal cycle would facilitate or anticipate the escape from Snowball Earth conditions when total solar irradiance or atmospheric CO2 levels were increased. The dynamics of the tropical circulation in Snowball Earth atmospheres differs substantially from that in the modern atmosphere. The analysis of the mean zonal momentum budget reveals that the mean flow meridional advection of absolute vorticity is primarily balanced by vertical diffusion of zonal momentum. The contribution of eddies is found to be even smaller than the contribution of mean flow vertical advection of zonal momentum, the latter being usually neglected in theories for the Hadley circulation, at least in its upper tropospheric branch. Suppressing vertical diffusion of horizontal momentum above 850 hPa leads to a stronger Hadley circulation. This behaviour cannot be understood from axisymmetric models of the atmosphere, nor idealized atmospheric general circulation models, which both predict a weakening of the Hadley circulation when the vertical viscosity is decreased globally. We

  11. Upper atmosphere research at INPE

    International Nuclear Information System (INIS)

    Clemesha, B.R.

    1984-01-01

    Upper atmosphere research at INPE is mainly concerned with the chemistry and dynamics of the stratosphere, upper mesosphere and lower thermosphere, and the middle thermosphere. Experimental work includes lidar observations of the stratospheric aerosol, measurements of stratospheric ozone by Dobson spectrophotometers and by balloon and rocket-borne sondes, lidar measurements of atmospheric sodium, and photometric observations of O, O 2 , OH and Na emissions, including interferrometric measurements of the OI6300 emission for the purpose of determing thermospheric winds and temperature. The airglow observations also include measurements of a number of emissions produced by the precipitation of energetic neutral particles generated by charge exchange in the ring current. Some recent results of INPE's upper atmosphere program are presented. (Author) [pt

  12. An archetype hydrogen atmosphere problem

    Science.gov (United States)

    Athay, R. G.; Mihalas, D.; Shine, R. A.

    1975-01-01

    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.

  13. An archetype hydrogen atmosphere problem

    International Nuclear Information System (INIS)

    Athay, R.G.; Mihalas, D.; Shine, R.A.

    1975-01-01

    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal, hydrostatic atmosphere at 20000K. The atmosphere is treated as being optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1,3-1,3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is non-trivial, and presents sufficient difficulty to have caused failure of at least one rather standard technique. The problem is thus a good archetype against which new methods, or new implementations of old methods may be tested. (Auth.)

  14. Atmospheres of Jupiter and Saturn

    International Nuclear Information System (INIS)

    Hunt, G.E.

    1981-01-01

    In this paper the current knowledge of the atmospheres of Jupiter and Saturn are reviewed making use of the extensive telescopic studies, International Ultraviolet Explorer Satellite observations and the measurements made during the recent Pioneer and Voyager flybys which have been supported by detailed theoretical studies. A detailed discussion is given of the composition of these atmospheres and the abundance ratios which provide insight into their original state and their evolution. The Voyager observations indicate a surprisingly close similarity between the weather systems of the Earth and the giant planets. Although both Jupiter and Saturn have internal heat sources, and are therefore star-like in their interiors, they appear to produce terrestrial-style weather systems. A detailed discussion is given of this work, which forms a major study of the Laboratory for Planetary Atmospheres at University College London. (author)

  15. Terrestrial atmosphere, water and astrobiology

    Directory of Open Access Journals (Sweden)

    Coradini M.

    2010-12-01

    Full Text Available Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bonds. The carbon-based molecules were either home made in the atmosphere and/or in submarine hydrothermal systems or delivered by meteorites and micrometeorites. The search for possible places beyond the earth where the trilogy atmosphere/water/life could exist is the main objective of astrobiology. Within the Solar System, exploration missions are dedicated to Mars, Europa, Titan and the icy bodies. The discovery of several hundreds of extrasolar planets opens the quest to the whole Milky Way.

  16. The role of ammonia in the chemistry of atmospheric aerosols

    International Nuclear Information System (INIS)

    Brosset, C.

    1979-01-01

    Data is presented on the concentrations of hydrogen and ammonium ions in aerosol samples taken under various meteorological conditions in different areas of Sweden, and implications for the atmospheric chemistry of aerosols are discussed. Particle compositions at coastal and inland stations were determined during situations when particle concentrations increased as much as a hundred times due to atmospheric transport from Europe or air movements from the east or west. Analysis of particle compositions during both types of particle episodes reveals variations in the H(+)/NH4(+) ratio which indicate that particles present over agricultural areas take up ammonia from the ground and release it over a forest district with acid lakes. The ratio is found to be dependent on the atmospheric partial pressure of ammonia at equilibrium, with the flow of ammonia to or from the ground and transport conditions also likely to influence the ratio

  17. Atomistic modeling of carbon Cottrell atmospheres in bcc iron

    Science.gov (United States)

    Veiga, R. G. A.; Perez, M.; Becquart, C. S.; Domain, C.

    2013-01-01

    Atomistic simulations with an EAM interatomic potential were used to evaluate carbon-dislocation binding energies in bcc iron. These binding energies were then used to calculate the occupation probability of interstitial sites in the vicinity of an edge and a screw dislocation. The saturation concentration due to carbon-carbon interactions was also estimated by atomistic simulations in the dislocation core and taken as an upper limit for carbon concentration in a Cottrell atmosphere. We obtained a maximum concentration of 10 ± 1 at.% C at T = 0 K within a radius of 1 nm from the dislocation lines. The spatial carbon distributions around the line defects revealed that the Cottrell atmosphere associated with an edge dislocation is denser than that around a screw dislocation, in contrast with the predictions of the classical model of Cochardt and colleagues. Moreover, the present Cottrell atmosphere model is in reasonable quantitative accord with the three-dimensional atom probe data available in the literature.

  18. Atmospheric processes on ice nanoparticles in molecular beams

    Directory of Open Access Journals (Sweden)

    Michal eFárník

    2014-02-01

    Full Text Available This review summarizes some recent experiments with ice nanoparticles (large water clusters in molecular beams and outlines their atmospheric relevance: (1 Investigation of mixed water–nitric acid particles by means of the electron ionization and sodium doping combined with photoionization revealed the prominent role of HNO3 molecule as the condensation nuclei. (2 The uptake of atmospheric molecules by water ice nanoparticles has been studied, and the pickup cross sections for some molecules exceed significantly the geometrical sizes of the ice nanoparticles. (3 Photodissociation of hydrogen halides on water ice particles has been shown to proceed via excitation of acidically dissociated ion pair and subsequent biradical generation and H3O dissociation. The photodissociation of CF2Cl2 molecule in clusters is also mentioned. Possible atmospheric consequences of all these results are briefly discussed.

  19. Surface cleaning of metal wire by atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Nakamura, T.; Buttapeng, C.; Furuya, S.; Harada, N.

    2009-01-01

    In this study, the possible application of atmospheric pressure dielectric barrier discharge plasma for the annealing of metallic wire is examined and presented. The main purpose of the current study is to examine the surface cleaning effect for a cylindrical object by atmospheric pressure plasma. The experimental setup consists of a gas tank, plasma reactor, and power supply with control panel. The gas assists in the generation of plasma. Copper wire was used as an experimental cylindrical object. This copper wire was irradiated with the plasma, and the cleaning effect was confirmed. The result showed that it is possible to remove the tarnish which exists on the copper wire surface. The experiment reveals that atmospheric pressure plasma is usable for the surface cleaning of metal wire. However, it is necessary to examine the method for preventing oxidization of the copper wire.

  20. Seductive Atmospheres: Using tools to effectuate spaces for Leadership Development

    DEFF Research Database (Denmark)

    Elmholdt, Kasper Trolle; Clausen, Rune Thorbjørn; Madsen, Mona T

    2018-01-01

    Hospital, this study investigates how a business game is used as a tool to effectuate episodic spaces for leadership development. The study reveals three tool affordances and discusses how they enable and constrain episodic spaces for development and further develops the notion of seductive atmospheres......This study applies an affordance lens to understand the use of management tools and how atmospheres for change and development are created and exploited. Drawing on an ethnographic case study of a consultant-facilitated change intervention among a group of research leaders at a Danish Public...... as an important mechanism. The article suggests that a broader understanding of the use of tools and the role of atmospheres is essential for understanding how episodic spaces for development come to work in relation to organizational change and development....

  1. Future of Atmospheric Neutrino Measurements

    International Nuclear Information System (INIS)

    Choubey, Sandhya

    2013-01-01

    Discovery of large θ 13 has opened up the possibility of determining the neutrino mass hierarchy and θ 23 octant through earth matter effects. The atmospheric neutrinos pick up large earth matter effects both in the ν e and ν μ channels, which if observed could lead to the determination of the mass hierarchy and θ 23 octant using this class of experiments in the near future. In this talk I review the status and prospects of future atmospheric neutrino measurements in determining the mass hierarchy and octant of θ 23

  2. Atmospheric-pressure plasma technology

    International Nuclear Information System (INIS)

    Kogelschatz, U

    2004-01-01

    Major industrial plasma processes operating close to atmospheric pressure are discussed. Applications of thermal plasmas include electric arc furnaces and plasma torches for generation of powders, for spraying refractory materials, for cutting and welding and for destruction of hazardous waste. Other applications include miniature circuit breakers and electrical discharge machining. Non-equilibrium cold plasmas at atmospheric pressure are obtained in corona discharges used in electrostatic precipitators and in dielectric-barrier discharges used for generation of ozone, for pollution control and for surface treatment. More recent applications include UV excimer lamps, mercury-free fluorescent lamps and flat plasma displays

  3. Plume spread and atmospheric stability

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The horizontal spread of a plume in atmospheric dispersion can be described by the standard deviation of horizontal direction. The widely used Pasquill-Gifford classes of atmospheric stability have assigned typical values of the standard deviation of horizontal wind direction and of the lapse rate. A measured lapse rate can thus be used to estimate the standard deviation of wind direction. It is examined by means of a large dataset of fast wind measurements how good these estimates are. (author) 1 fig., 2 refs.

  4. Baseline atmospheric program Australia 1993

    International Nuclear Information System (INIS)

    Francey, R.J.; Dick, A.L.; Derek, N.

    1996-01-01

    This publication reports activities, program summaries and data from the Cape Grim Baseline Air Pollution Station in Tasmania, during the calendar year 1993. These activities represent Australia's main contribution to the Background Air Pollution Monitoring Network (BAPMoN), part of the World Meteorological Organization's Global Atmosphere Watch (GAW). The report includes 5 research reports covering trace gas sampling, ozone and radon interdependence, analysis of atmospheric dimethylsulfide and carbon-disulfide, sampling of trace gas composition of the troposphere, and sulfur aerosol/CCN relationship in marine air. Summaries of program reports for the calendar year 1993 are also included. Tabs., figs., refs

  5. Characterizing Convection in Stellar Atmospheres

    International Nuclear Information System (INIS)

    Tanner, Joel; Basu, Sarbani; Demarque, Pierre; Robinson, Frank

    2011-01-01

    We perform 3D radiative hydrodynamic simulations to study the properties of convection in the superadiabatic layer of stars. The simulations show differences in both the stratification and turbulent quantities for different types of stars. We extract turbulent pressure and eddy sizes, as well as the T-τ relation for different stars and find that they are sensitive to the energy flux and gravity. We also show that contrary to what is usually assumed in the field of stellar atmospheres, the structure and gas dynamics of simulations of turbulent atmospheres cannot be parameterized with T eff and log(g) alone.

  6. Review: the atmospheric boundary layer

    Science.gov (United States)

    Garratt, J. R.

    1994-10-01

    An overview is given of the atmospheric boundary layer (ABL) over both continental and ocean surfaces, mainly from observational and modelling perspectives. Much is known about ABL structure over homogeneous land surfaces, but relatively little so far as the following are concerned, (i) the cloud-topped ABL (over the sea predominantly); (ii) the strongly nonhomogeneous and nonstationary ABL; (iii) the ABL over complex terrain. These three categories present exciting challenges so far as improved understanding of ABL behaviour and improved representation of the ABL in numerical models of the atmosphere are concerned.

  7. The First Atmospheric Characterization of a Habitable-Zone Exoplanet

    Science.gov (United States)

    Stevenson, Kevin; Bean, Jacob; Charbonneau, David; Desert, Jean-Michel; Fortney, Jonathan; Irwin, Jonathan; Kreidberg, Laura; Line, Michael; Montet, Ben; Morley, Caroline

    2015-10-01

    Exoplanet surveys have recently revealed nearby planets orbiting within stellar habitable zones. This highly-anticipated breakthrough brings us one step closer in our quest to identify cosmic biosignatures, the indicators of extrasolar life. To achieve our goal, we must first study the atmospheres of these temperate worlds to measure their compositions and determine the prevalence of obscuring clouds. Using observations from the K2 mission, Co-I Montet recently announced the discovery of a 2.2 Earth-radii planet within the habitable zone of its relatively bright, nearby M dwarf parent star, K2-18. This temperate world is currently the best habitable-zone target for atmospheric characterization. Congruent with currently planned HST observations, we propose a Spitzer program to measure the transmission spectrum of the first habitable-zone exoplanet. Both telescopes are essential to revealing K2-18b's chemical composition. In a cloud-free, hydrogen-dominated atmosphere, the precision achieved by these measurements will be sufficient to detect methane, ammonia, and water vapor, which are the dominant C, N, and O bearing species at these temperatures. In turn, elemental abundance constraints from a primordial atmosphere can tell us about the composition of a protoplanetary disk in which Earth-like planets could have formed. Conversely, if the atmosphere contains thick clouds then the multi-wavelength observations from K2, HST, and Spitzer will constrain the clouds' properties. Because temperature plays a key role in the formation of clouds, their detection within the atmosphere of this habitable-zone exoplanet would be an important signpost that serves as a guide to future investigations of smaller, rocky exoplanets. As K2 continues discovering more habitable-zone planets, it is imperative that we perform spectral reconnaissance with Spitzer to determine their physical characteristics and begin understanding the prevalence of potentially-obscuring clouds prior to the

  8. Clouds and Hazes in Exoplanet Atmospheres

    OpenAIRE

    Marley, Mark S.; Ackerman, Andrew S.; Cuzzi, Jeffrey N.; Kitzmann, Daniel

    2013-01-01

    Clouds and hazes are commonplace in the atmospheres of solar system planets and are likely ubiquitous in the atmospheres of extrasolar planets as well. Clouds affect every aspect of a planetary atmosphere, from the transport of radiation, to atmospheric chemistry, to dynamics and they influence - if not control - aspects such as surface temperature and habitability. In this review we aim to provide an introduction to the role and properties of clouds in exoplanetary atmospheres. We consider t...

  9. Environmental factor atmosphere. Umweltfaktor Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Pogosjan, C P

    1981-01-01

    This book presents chapters on constitution of atmosphere, sun energy, air temperature, ocean-currents and heat transfer, annual specialities of pressure field, low and high pressure areas, hurricanes, formation of clouds and rainfall, climate variations, weather and weather forecast, artificial influence of weather and climate.

  10. Millimeter Wave Atmospheric Radiometry Observations.

    Science.gov (United States)

    1981-03-27

    structure of the atmosphere would be very important. Rufton [20] combined thermal sensor technology for microthermal measurements with radiosonde...fromT2 h n relationships with CT(h) at least for optical effects. Bufton obtained the mean-square temperature difference between two microthermal probes

  11. Exploring the Atmosphere Using Smartphones

    Science.gov (United States)

    Monteiro, Martin; Vogt, Patrik; Stari, Cecilia; Cabeza, Cecilia; Marti, Arturo C.

    2016-01-01

    The characteristics of the inner layer of the atmosphere, the troposphere, are determinant for Earth's life. In this experience we explore the first hundreds of meters using a smartphone mounted on a quadcopter. Both the altitude and the pressure are obtained using the smartphone's sensors. We complement these measures with data collected from the…

  12. Atmospheric contamination during ultrasonic scaling

    NARCIS (Netherlands)

    Timmerman, MF; Menso, L; Steinfort, J; van Winkelhoff, AJ; van der Weijden, GA

    Objective: The aim of this study was to determine the microbial atmospheric contamination during initial periodontal treatment using a piezoelectric ultrasonic scaler in combination with either high-volume evacuation (HVE) or conventional dental suction (CDS). Methods: The study included 17

  13. the Martian atmospheric boundary layer

    DEFF Research Database (Denmark)

    Petrosyan, A.; Galperin, B.; Larsen, Søren Ejling

    2011-01-01

    . This portion of the atmosphere is extremely important, both scientifically and operationally, because it is the region within which surface lander spacecraft must operate and also determines exchanges of heat, momentum, dust, water, and other tracers between surface and subsurface reservoirs and the free...

  14. Would be the Atmosphere Chaotic?

    Directory of Open Access Journals (Sweden)

    Isimar de Azevedo Santos

    2013-07-01

    Full Text Available The atmosphere has often been considered “chaotic” when in fact the “chaos” is a manifestation of the models that simulate it, which do not include all the physical mechanisms that exist within it. A weather prediction cannot be perfectly verified after a few days of integration due to the inherent nonlinearity of the equations of the hydrodynamic models. The innovative ideas of Lorenz led to the use of the ensemble forecast, with clear improvements in the quality of the numerical weather prediction. The present study addresses the statement that “even with perfect models and perfect observations, the ‘chaotic’ nature of the atmosphere would impose a finite limit of about two weeks to the predictability of the weather” as the atmosphere is not necessarily “chaotic”, but the models used in the simulation of atmospheric processes are. We conclude, therefore, that potential exists for developments to increase the horizon of numerical weather prediction, starting with better models and observations.

  15. Airborne Atmospheric Aerosol Measurement System

    Science.gov (United States)

    Ahn, K.; Park, Y.; Eun, H.; Lee, H.

    2015-12-01

    It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

  16. Atmospheric Research 2011 Technical Highlights

    Science.gov (United States)

    2012-01-01

    The 2011 Technical Highlights describes the efforts of all members of Atmospheric Research. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  17. Climate of the upper atmosphere

    Czech Academy of Sciences Publication Activity Database

    Bremer, J.; Laštovička, Jan; Mikhailov, A. V.; Altadill, D.; Pal, B.; Burešová, Dalia; Franceschi de, G.; Jacobi, C.; Kouris, S. S.; Perrone, L.; Turunen, E.

    2009-01-01

    Roč. 52, 3/4 (2009), s. 273-299 ISSN 1593-5213 R&D Projects: GA MŠk OC 091 Institutional research plan: CEZ:AV0Z30420517 Keywords : Ionosphere * trends * atmospheric waves * ionospheric variability * incoherent radar * space weather Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.548, year: 2009

  18. Forecasting global atmospheric CO2

    International Nuclear Information System (INIS)

    Agusti-Panareda, A.; Massart, S.; Boussetta, S.; Balsamo, G.; Beljaars, A.; Engelen, R.; Jones, L.; Peuch, V.H.; Chevallier, F.; Ciais, P.; Paris, J.D.; Sherlock, V.

    2014-01-01

    A new global atmospheric carbon dioxide (CO 2 ) real-time forecast is now available as part of the preoperational Monitoring of Atmospheric Composition and Climate - Interim Implementation (MACC-II) service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS). One of the strengths of the CO 2 forecasting system is that the land surface, including vegetation CO 2 fluxes, is modelled online within the IFS. Other CO 2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO 2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP) system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO 2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO 2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO 2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO 2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO 2 fluxes also lead to accumulating errors in the CO 2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO 2 fluxes compared to total optimized fluxes and the atmospheric CO 2 compared to observations. The largest biases in the atmospheric CO 2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO 2 analyses based on the assimilation of CO 2 products retrieved from satellite

  19. Observations of atmospheric ammonia from TANSO-FTS/GOSAT

    Science.gov (United States)

    Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Shiomi, Kei

    2017-04-01

    Atmospheric ammonia has large impacts on the nitrogen cycles or atmospheric environment such as nucleation of PM2.5 particles. It is reported that ammonia in the atmosphere has been increasing rapidly with the growth of population globally and this trend must continue in the future. Satellite observation is an effective approach to get to know the global perspectives of the gas. Atmospheric ammonia is observable using the thermal infrared (TIR) spectra, and IASI, TES and CrIS had been revealed those distributions. GOSAT also has TIR band including the ammonia absorption bands. GOSAT has the shorter revisit cycle than that of the other hyper-spectral TIR sounders mentioned above, therefore, the shorter time-scale events can be represented. In addition to the importance of the impacts of ammonia itself, the concentration ratio between ammonia and the other trace gases such as CO which is one of the main targets of the GOSAT-2 project is useful as the indicator of their emission sources. In this study, we introduce an algorithm to retrieve the column amount of atmospheric ammonia based on non-linear optimal estimation (Rogers, 2000) from GOSAT spectra in the ammonia absorption band between 960 - 970 cm-1. Temperature and water vapor profiles are estimated in advance of the ammonia retrieval. The preliminary results showed significant high concentrations of ammonia in the Northern India and the Eastern China as pointed out in the previous researches. We will discuss the global distribution of ammonia in the presentation.

  20. Finding Atmospheric Composition (AC) Metadata

    Science.gov (United States)

    Strub, Richard F..; Falke, Stefan; Fiakowski, Ed; Kempler, Steve; Lynnes, Chris; Goussev, Oleg

    2015-01-01

    The Atmospheric Composition Portal (ACP) is an aggregator and curator of information related to remotely sensed atmospheric composition data and analysis. It uses existing tools and technologies and, where needed, enhances those capabilities to provide interoperable access, tools, and contextual guidance for scientists and value-adding organizations using remotely sensed atmospheric composition data. The initial focus is on Essential Climate Variables identified by the Global Climate Observing System CH4, CO, CO2, NO2, O3, SO2 and aerosols. This poster addresses our efforts in building the ACP Data Table, an interface to help discover and understand remotely sensed data that are related to atmospheric composition science and applications. We harvested GCMD, CWIC, GEOSS metadata catalogs using machine to machine technologies - OpenSearch, Web Services. We also manually investigated the plethora of CEOS data providers portals and other catalogs where that data might be aggregated. This poster is our experience of the excellence, variety, and challenges we encountered.Conclusions:1.The significant benefits that the major catalogs provide are their machine to machine tools like OpenSearch and Web Services rather than any GUI usability improvements due to the large amount of data in their catalog.2.There is a trend at the large catalogs towards simulating small data provider portals through advanced services. 3.Populating metadata catalogs using ISO19115 is too complex for users to do in a consistent way, difficult to parse visually or with XML libraries, and too complex for Java XML binders like CASTOR.4.The ability to search for Ids first and then for data (GCMD and ECHO) is better for machine to machine operations rather than the timeouts experienced when returning the entire metadata entry at once. 5.Metadata harvest and export activities between the major catalogs has led to a significant amount of duplication. (This is currently being addressed) 6.Most (if not all

  1. Atmospheric anomalies in summer 1908: Water in the atmosphere

    Science.gov (United States)

    Gladysheva, O. G.

    2011-10-01

    A gigantic noctilucent cloud field was formed and different solar halos were observed after the Tunguska catastrophe. To explain these anomalous phenomena, it is necessary to assume that a large quantity of water was carried into the atmosphere, which indicates that the Tunguska cosmic body was of a comet origin. According to rough estimates, the quantity of water that is released into the atmosphere as a result of a cosmic body's destruction is more than 1010 kg. The observation of a flying object in an area with a radius of ≥700 km makes it possible to state that the Tunguska cosmic body looked like a luminous coma with a diameter not smaller than ≥10 km and became visible at heights of >500 km. The assumption that the Tunguska cosmic body started disintegrating at a height of ˜1000 km explains the formation of an area where its mater diffused and formed a luminous area above Europe.

  2. Afghanistan Reveals the Source of Atmospheric Nitrogen during North Western Monsoons

    Directory of Open Access Journals (Sweden)

    Ayse Ozlem Goral

    2014-10-01

    Full Text Available Chemical analysis of soil samples collected from Afghanistan have shown that those regions having capability of generating wind-induced dust at northern and south western territories have the capability of supplying nitrates and nitrites in addition to crustal materials. Together with all the other essential elements Afghan soil samples has the potential of controlling so far unexplained phytoplankton bloom and excess nitrate and nitrites during the course of NWM (North Western Monsoons over the surface waters of Arabian Sea

  3. Afghanistan Reveals the Source of Atmospheric Nitrogen during North Western Monsoons

    International Nuclear Information System (INIS)

    Goral, A.O.

    2014-01-01

    Chemical analysis of soil samples collected from Afghanistan have shown that those regions having capability of generating wind-induced dust at northern and south western territories have the capability of supplying nitrates and nitrites in addition to crustal materials. Together with all the other essential elements Afghan soil samples has the potential of controlling so far unexplained phytoplankton bloom and excess nitrate and nitrites during the course of NWM (North Western Monsoons) over the surface waters of Arabian Sea. (author)

  4. Anthropogenic osmium in rain and snow reveals global-scale atmospheric contamination.

    Science.gov (United States)

    Chen, Cynthia; Sedwick, Peter N; Sharma, Mukul

    2009-05-12

    Osmium is one of the rarer elements in seawater, with typical concentration of approximately 10 x 10(-15) g g(-1) (5.3 x 10(-14) mol kg(-1)). The osmium isotope composition ((187)Os/(188)Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (approximately 1.3) and mantle/cosmic dust (approximately 0.13). Here, we show that the (187)Os/(188)Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximately 0.2) that are processed to extract platinum and other metals to be used primarily in automobile catalytic converters. Present-day surface seawater has a lower (187)Os/(188)Os ratio (approximately 0.95) than deep waters, suggesting that human activities have altered the isotope composition of the world's oceans and impacted the global geochemical cycle of osmium. The contamination of the surface ocean is particularly remarkable given that osmium has few industrial uses. The pollution may increase with growing demand for platinum-based catalysts.

  5. Atmospheric evolution on inhabited and lifeless worlds

    CERN Document Server

    Catling, David C

    2017-01-01

    As the search for Earth-like exoplanets gathers pace, in order to understand them, we need comprehensive theories for how planetary atmospheres form and evolve. Written by two well-known planetary scientists, this text explains the physical and chemical principles of atmospheric evolution and planetary atmospheres, in the context of how atmospheric composition and climate determine a planet's habitability. The authors survey our current understanding of the atmospheric evolution and climate on Earth, on other rocky planets within our Solar System, and on planets far beyond. Incorporating a rigorous mathematical treatment, they cover the concepts and equations governing a range of topics, including atmospheric chemistry, thermodynamics, radiative transfer, and atmospheric dynamics, and provide an integrated view of planetary atmospheres and their evolution. This interdisciplinary text is an invaluable one-stop resource for graduate-level students and researchers working across the fields of atmospheric science...

  6. Improved Mars Upper Atmosphere Climatology

    Science.gov (United States)

    Bougher, S. W.

    2004-01-01

    The detailed characterization of the Mars upper atmosphere is important for future Mars aerobraking activities. Solar cycle, seasonal, and dust trends (climate) as well as planetary wave activity (weather) are crucial to quantify in order to improve our ability to reasonably depict the state of the Mars upper atmosphere over time. To date, our best information is found in the Mars Global Surveyor (MGS) Accelerometer (ACC) database collected during Phase 1 (Ls = 184 - 300; F10.7 = 70 - 90) and Phase 2 (Ls = 30 - 90; F10.7 = 90 - 150) of aerobraking. This database (100 - 170 km) consists of thermospheric densities, temperatures, and scale heights, providing our best constraints for exercising the coupled Mars General Circulation Model (MGCM) and the Mars Thermospheric General Circulation Model (MTGCM). The Planetary Data System (PDS) contains level 0 and 2 MGS Accelerometer data, corresponding to atmospheric densities along the orbit track. Level 3 products (densities, temperatures, and scale heights at constant altitudes) are also available in the PDS. These datasets provide the primary model constraints for the new MGCM-MTGCM simulations summarized in this report. Our strategy for improving the characterization of the Mars upper atmospheres using these models has been three-fold : (a) to conduct data-model comparisons using the latest MGS data covering limited climatic and weather conditions at Mars, (b) to upgrade the 15-micron cooling and near-IR heating rates in the MGCM and MTGCM codes for ad- dressing climatic variations (solar cycle and seasonal) important in linking the lower and upper atmospheres (including migrating tides), and (c) to exercise the detailed coupled MGCM and MTGCM codes to capture and diagnose the planetary wave (migrating plus non-migrating tidal) features throughout the Mars year. Products from this new suite of MGCM-MTGCM coupled simulations are being used to improve our predictions of the structure of the Mars upper atmosphere for the

  7. Model for Simulation Atmospheric Turbulence

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik

    1976-01-01

    A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance...... eigenfunctions and estimates of the distributions of the corresponding expansion coefficients. The simulation method utilizes the eigenfunction expansion procedure to produce preliminary time histories of the three velocity components simultaneously. As a final step, a spectral shaping procedure is then applied....... The method is unique in modeling the three velocity components simultaneously, and it is found that important cross-statistical features are reasonably well-behaved. It is concluded that the model provides a practical, operational simulator of atmospheric turbulence....

  8. Modeling of atmospheric pollutant transfers

    International Nuclear Information System (INIS)

    Jourdain, F.

    2007-01-01

    Modeling is today a common tool for the evaluation of the environmental impact of atmospheric pollution events, for the design of air monitoring networks or for the calculation of pollutant concentrations in the ambient air. It is even necessary for the a priori evaluation of the consequences of a pollution plume. A large choice of atmospheric transfer codes exist but no ideal tool is available which allows to model all kinds of situations. The present day approach consists in combining different types of modeling according to the requested results and simulations. The CEA has a solid experience in this domain and has developed independent tools for the impact and safety studies relative to industrial facilities and to the management of crisis situations. (J.S.)

  9. Particulate carbon in the atmosphere

    International Nuclear Information System (INIS)

    Surakka, J.

    1992-01-01

    Carbonaceous aerosols are emitted to the atmosphere in combustion processes. Carbon particles are very small and have a long residence time in the air. Black Carbon, a type of carbon aerosol, is a good label when transport of combustion emissions in the atmosphere is studied. It is also useful tool in air quality studies. Carbon particles absorb light 6.5 to 8 times stronger than any other particulate matter in the air. Their effect on decreasing visibility is about 50 %. Weather disturbances are also caused by carbon emissions e.g. in Kuwait. Carbon particles have big absorption surface and capacity to catalyze different heterogenous reactions in air. Due to their special chemical and physical properties particulate carbon is a significant air pollution specie, especially in urban air. Average particulate carbon concentration of 5.7 μg/m 2 have been measured in winter months in Helsinki

  10. Atmospheric dispersion and environmental consequences

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1992-11-01

    Methods are described for assessing early radiation doses due to atmospheric releases of radionuclides, i.e. inhalation and external exposure from the plume and from deposited activity. Data to be used in these assessments are presented. The purpose of the present work is to evaluate methods and data that could be used in emergency situations as well as for emergency planning purposes. The most important direct pathways following a release of airborne radionuclides to the atmosphere are the inhalation pathway and the external exposure pathway from ground-deposited activity. For long-lived radionuclides like 134 Cs and 137 Cs the committed effective external dose from deposited acitivity is 1-2 orders of magnitude larger than the committed effective dose from inhalation. Similarly, the committed effective dose from inhalation is 1-2 orders of magnitude larger than the external γ-dose originating directly from the plume. (au) (21 tabs., 2 ills., 37 refs.)

  11. Atmospheric Chemistry and Air Pollution

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Gaffney

    2003-01-01

    Full Text Available Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozone and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.

  12. Atmospheric Radiation Measurement Program plan

    International Nuclear Information System (INIS)

    1990-02-01

    In order to understand energy's role in anthropogenic global climate change, significant reliance is being placed on General Circulation Models (GCMs). A major goal is to foster the development of GCMs capable of predicting the timing and magnitude of greenhouse gas-induced global warming and the regional effects of such warming. The Atmospheric Radiation Measurement (ARM) Program will contribute to the Department of Energy goal by improving the treatment of cloud radiative forcing and feedbacks in GCMs. Two issues will be addressed: the radiation budget and its spectral dependence and the radiative and other properties of clouds. The experimental objective of the ARM Program is to characterize empirically the radiative processes in the Earth's atmosphere with improved resolution and accuracy. A key to this characterization is the effective treatment of cloud formation and cloud properties in GCMs. Through this characterization of radiative properties, it will be possible to understand both the forcing and feedback effects. 19 refs., 4 figs., 2 tabs

  13. Models for infrared atmospheric radiation

    Science.gov (United States)

    Tiwari, S. N.

    1976-01-01

    Line and band models for infrared spectral absorption are discussed. Radiative transmittance and integrated absorptance of Lorentz, Doppler, and voigt line profiles were compared for a range of parameters. It was found that, for the intermediate path lengths, the combined Lorentz-Doppler (Voigt) profile is essential in calculating the atmospheric transmittance. Narrow band model relations for absorptance were used to develop exact formulations for total absorption by four wide band models. Several continuous correlations for the absorption of a wide band model were compared with the numerical solutions of the wide band models. By employing the line-by-line and quasi-random band model formulations, computational procedures were developed for evaluating transmittance and upwelling atmospheric radiance. Homogeneous path transmittances were calculated for selected bands of CO, CO2, and N2O and compared with experimental measurements. The upwelling radiance and signal change in the wave number interval of the CO fundamental band were also calculated.

  14. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  15. Nighttime atmospheric chemistry of iodine

    Science.gov (United States)

    Saiz-Lopez, Alfonso; Plane, John M. C.; Cuevas, Carlos A.; Mahajan, Anoop S.; Lamarque, Jean-François; Kinnison, Douglas E.

    2016-12-01

    Little attention has so far been paid to the nighttime atmospheric chemistry of iodine species. Current atmospheric models predict a buildup of HOI and I2 during the night that leads to a spike of IO at sunrise, which is not observed by measurements. In this work, electronic structure calculations are used to survey possible reactions that HOI and I2 could undergo at night in the lower troposphere, and hence reduce their nighttime accumulation. The new reaction NO3+ HOI → IO + HNO3 is proposed, with a rate coefficient calculated from statistical rate theory over the temperature range 260-300 K and at a pressure of 1000 hPa to be k(T) = 2.7 × 10-12 (300 K/T)2.66 cm3 molecule-1 s-1. This reaction is included in two atmospheric models, along with the known reaction between I2 and NO3, to explore a new nocturnal iodine radical activation mechanism. The results show that this iodine scheme leads to a considerable reduction of nighttime HOI and I2, which results in the enhancement of more than 25 % of nighttime ocean emissions of HOI + I2 and the removal of the anomalous spike of IO at sunrise. We suggest that active nighttime iodine can also have a considerable, so far unrecognized, impact on the reduction of the NO3 radical levels in the marine boundary layer (MBL) and hence upon the nocturnal oxidizing capacity of the marine atmosphere. The effect of this is exemplified by the indirect effect on dimethyl sulfide (DMS) oxidation.

  16. Toxic metals in the atmosphere

    International Nuclear Information System (INIS)

    Munoz-Ribadeneira, F.J.; Mo, T.; Canoy, M.J.

    1975-05-01

    Methods used in Puerto Rico for monitoring toxic metals in the atmosphere are described. Air sampling machines are placed at heights from 15 to 25 ft above the surface and the tapes are subjected to neutron activation and γ spectroscopy. The concentrations of up to 33 elements can be determined with precision and sensitivity without destroying the tapes, which can then be used for analysis by other methods. (U.S.)

  17. Climate of the upper atmosphere

    Directory of Open Access Journals (Sweden)

    Christoph Jacobi

    2009-06-01

    Full Text Available

    In the frame of the European COST 296 project (Mitigation of Ionospheric Effects on Radio Systems, MIERS

    investigations of the climate of the upper atmosphere have been carried out during the last four years to obtain

    new information on the upper atmosphere. Mainly its ionospheric part has been analysed as the ionosphere

    most essential for the propagation of radio waves. Due to collaboration between different European partners

    many new results have been derived in the fields of long-term trends of different ionospheric and related atmospheric

    parameters, the investigations of different types of atmospheric waves and their impact on the ionosphere,

    the variability of the ionosphere, and the investigation of some space weather effects on the ionosphere.


  18. Atmospheric neutrinos in Soudan 2.

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, M. C.; Soudan 2 Collaboration

    1999-03-30

    Soudan 2 has measured the atmospheric neutrino flavor ratio with 4.2 fiducial kiloton-years of exposure. It measures a flavor ratio of 0.66 {+-} 0.11(stat), inconsistent with the expected ratio but consistent with the hypothesis of neutrino oscillations and the Super-Kamiokande data. In a sample of events with good angular resolution, fits to the L/E distribution suggest that {Delta}m{sup 2} > 10{sup {minus}3} eV{sup 2}.

  19. The atmosphere as particle detector

    Science.gov (United States)

    Stanev, Todor

    1990-01-01

    The possibility of using an inflatable, gas-filled balloon as a TeV gamma-ray detector on the moon is considered. By taking an atmosphere of Xenon gas there, or by extracting it on the moon, a layman's detector design is presented. In spite of its shortcomings, the exercise illustrates several of the novel features offered by particle physics on the moon.

  20. Oblique Longwave Infrared Atmospheric Compensation

    Science.gov (United States)

    2017-09-14

    been updated to take terrain shape from a digital elevation model into account, as well as multiple viewing geometries for the different pixels...utilizing a digital elevation map). In summary, OISAC simply estimates line contributions for the transmission and path radiance, τ̄` and L̄p,`, from the...and Atmospheric Administration (NOAA) National Operational Model Archive and Distribution System ( NOMADS ) [34]. At- mospheric estimates from the

  1. Light extinction in the atmosphere

    International Nuclear Information System (INIS)

    Laulainen, N.

    1992-06-01

    Atmospheric aerosol particles originating from natural sources, such as volcanos and sulfur-bearing gas emissions from the oceans, and from human sources, such as sulfur emissions from fossil fuel combustion and biomass burning, strongly affect visual air quality and are suspected to significantly affect radiative climate forcing of the planet. During the daytime, aerosols obscure scenic vistas, while at night they diminish our ability to observe stellar objects. Scattering of light is the main means by which aerosols attenuate and redistribute light in the atmosphere and by which aerosols can alter and reduce visibility and potentially modify the energy balance of the planet. Trends and seasonal variability of atmospheric aerosol loading, such as column-integrated light extinction or optical depth, and how they may affect potential climate change have been difficult to quantify because there have been few observations made of important aerosol optical parameters, such as optical depth, over the globe and over time and often these are of uneven quality. To address questions related to possible climate change, there is a pressing need to acquire more high-quality aerosol optical depth data. Extensive deployment of improved solar radiometers over the next few years will provide higher-quality extinction data over a wider variety of locations worldwide. An often overlooked source of turbidity data, however, is available from astronomical observations, particularly stellar photoelectric photometry observations. With the exception of the Project ASTRA articles published almost 20 years ago, few of these data ever appear in the published literature. This paper will review the current status of atmospheric extinction observations, as highlighted by the ASTRA work and augmented by more recent solar radiometry measurements

  2. Earth’s Earliest Atmospheres

    Science.gov (United States)

    Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

    2010-01-01

    Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth’s atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth’s subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases. PMID:20573713

  3. Atmospheric-pressure plasma jet

    Science.gov (United States)

    Selwyn, Gary S.

    1999-01-01

    Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

  4. Equipment selection for atmospheric drying

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, P D; Bhattacharyya, S [Nuclear Power Corporation, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Heavy water management is a major factor in deciding the economics of the PHWRs. Hence it is necessary to have an efficient recovery system, for the heavy water vapour escaping from various process systems and maintain a dry atmosphere in the recovery areas. While the basic objective of the atmospheric drying system is to maximize recovery and to minimize stack losses, it is equally important to optimally design the system with due consideration to operational and maintenance aspects. At present, heavy water vapour recovery in the existing Nuclear Power Plants (NPPs) is carried out by dryers of dual fixed bed design. While moving bed design could have some advantages, this has not been adopted so far because of the cumbersome mechanical design involved and special requirements for nuclear application. Developmental work done in this direction has resulted in compact alternative designs. In one of the designs, the change over from adsorption to regeneration is achieved by rotating the bed slowly. This concept is further refined in another alternative using a dessicant wheel. This paper contains brief equipment description of different designs; enumerates the design requirements of an atmospheric drying system for reactor building; describes steps for designing fixed bed type D{sub 2}O vapour recovery system, and highlights advances in dryer technology. (author). 2 refs., 4 figs., 1 ill.

  5. Atmospheric processes over complex terrain

    Science.gov (United States)

    Banta, Robert M.; Berri, G.; Blumen, William; Carruthers, David J.; Dalu, G. A.; Durran, Dale R.; Egger, Joseph; Garratt, J. R.; Hanna, Steven R.; Hunt, J. C. R.

    1990-06-01

    A workshop on atmospheric processes over complex terrain, sponsored by the American Meteorological Society, was convened in Park City, Utah from 24 vto 28 October 1988. The overall objective of the workshop was one of interaction and synthesis--interaction among atmospheric scientists carrying out research on a variety of orographic flow problems, and a synthesis of their results and points of view into an assessment of the current status of topical research problems. The final day of the workshop was devoted to an open discussion on the research directions that could be anticipated in the next decade because of new and planned instrumentation and observational networks, the recent emphasis on development of mesoscale numerical models, and continual theoretical investigations of thermally forced flows, orographic waves, and stratified turbulence. This monograph represents an outgrowth of the Park City Workshop. The authors have contributed chapters based on their lecture material. Workshop discussions indicated interest in both the remote sensing and predictability of orographic flows. These chapters were solicited following the workshop in order to provide a more balanced view of current progress and future directions in research on atmospheric processes over complex terrain.

  6. Atmospheric phenomena deduced from radiosonde and GPS ...

    Indian Academy of Sciences (India)

    gation and atmospheric modeling studies. ... the earth. Atmosphere causes refraction of radio signals as it passes through it. This time ... from cloud, aerosol, precipitation and it provides ... in the troposphere have strong influence on tropical.

  7. MODIS/Aqua Atmosphere Aeronet Subsetting Product

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS/Aqua Atmosphere Aeronet Subsetting Product (MYDARNSS) consists of MODIS Atmosphere and Ancillary Products subsets that are generated over a number of...

  8. Atmospheric Sondes and Method for Tracking

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A system for wind profiling comprises sondes for being borne through the atmosphere by balloons and transmitting signals enabling identifying the sondes, and...

  9. Observations and Modeling of Atmospheric Radiance Structure

    National Research Council Canada - National Science Library

    Wintersteiner, Peter

    2001-01-01

    The overall purpose of the work that we have undertaken is to provide new capabilities for observing and modeling structured radiance in the atmosphere, particularly the non-LTE regions of the atmosphere...

  10. Clean Air Slots Amid Atmospheric Pollution

    Science.gov (United States)

    Hobbs, Peter V.

    2002-01-01

    This article investigates the mechanism for those layers in the atmosphere that are free of air borne pollution even though the air above and below them carry pollutants. Atmospheric subsidence is posed as a mechanism for this phenomenon.

  11. Energy balance at the soil atmosphere interface

    NARCIS (Netherlands)

    Sedighi, M; Hepburn, B.D.P.; Thomas, HR; Vardon, P.J.

    2016-01-01

    Soil atmospheric interactions play an important role within the thermal energy balance and seasonal temperature variations of the ground. This paper presents a formulation for the surface boundary conditions related to interactions between soil and atmosphere. The boundary condition formulated

  12. Atmospheric anthropic impacts tracked by the French atmospheric mobile observatory

    Science.gov (United States)

    Cuesta, J.; Chazette, P.; Flamant, P. H.

    2009-04-01

    A new ATmospheric Mobile ObServatory, so called "ATMOS", has been developed by the LiMAG "Lidar, Meteorology and Geophysics" team of the Institut Pierre Simon Laplace (IPSL) in France, in order to contribute to international field campaigns for studying atmospheric physico-chemistry, air quality and climate (i.e. aerosols, clouds, trace gazes, atmospheric dynamics and energy budget) and the ground-based validation of satellite observations. ATMOS has been deployed in the framework of i) LISAIR, for monitoring air quality in Paris in 2005, ii) AMMA "African Monsoon Multidisciplinary Analysis", in Tamanrasset and in Niamey for observing the aerosols and the atmospheric boundary layer in the Sahara and in the Sahel in 2006, iii) COPS "Convectively and Orographycally driven Precipitation Study" in the Rhin Valley in 2007 and iv) the validation of the spatial mission CALIPSO, launched in April 2006. In the coming years, ATMOS will be deployed i) in the Paris Megacity, in the framework of MEGAPOLI (2009-2010), ii) in southern France (near Marseille) for the Chemistry-Aerosol Mediterranean Experiment CHARMEX (2011-2012) and iii) the validation of ADM-Aeolus in 2010-2011 and Earth-Care in 2012. ATMOS payload is modular, accounting for the different platforms, instruments and measuring techniques. The deployment of ATMOS is an essential contribution to field campaigns, complementing the fixed sites, and a potential alternative of airborne platforms, heavier and more expensive. ATMOS mobile payload comprises both the remote sensing platform MOBILIS ("Moyens mOBIles de téLédetection de l'IPSL") and the in-situ physico-chemical station SAMMO ("Station Aérosols et chiMie MObile"). MOBILIS is an autonomous and high-performance system constituted by a full set of active and passive remote sensing instrumentation (i.e. Lidars and radiometers), whose payload may be adapted for either i) long term fixed monitoring in a maritime container or a shelter, ii) ground-based transect

  13. Determining Atmospheric Pressure Using a Water Barometer

    Science.gov (United States)

    Lohrengel, C. Frederick, II; Larson, Paul R.

    2012-01-01

    The atmosphere is an envelope of compressible gases that surrounds Earth. Because of its compressibility and nonuniform heating by the Sun, it is in constant motion. The atmosphere exerts pressure on Earth's surface, but that pressure is in constant flux. This experiment allows students to directly measure atmospheric pressure by measuring the…

  14. Ozone, Climate, and Global Atmospheric Change.

    Science.gov (United States)

    Levine, Joel S.

    1992-01-01

    Presents an overview of global atmospheric problems relating to ozone depletion and global warming. Provides background information on the composition of the earth's atmosphere and origin of atmospheric ozone. Describes causes, effects, and evidence of ozone depletion and the greenhouse effect. A vignette provides a summary of a 1991 assessment of…

  15. The Upper Atmosphere; Threshold of Space.

    Science.gov (United States)

    Bird, John

    This booklet contains illustrations of the upper atmosphere, describes some recent discoveries, and suggests future research questions. It contains many color photographs. Sections include: (1) "Where Does Space Begin?"; (2) "Importance of the Upper Atmosphere" (including neutral atmosphere, ionized regions, and balloon and investigations); (3)…

  16. Carbonaceous content of atmospheric aerosols in Lisbon urban atmosphere

    Science.gov (United States)

    Mirante, Fátima; Oliveira, C.; Martins, N.; Pio, C.; Caseiro, A.; Cerqueira, M.; Alves, C.; Oliveira, C.; Oliveira, J.; Camões, F.; Matos, M.; Silva, H.

    2010-05-01

    Lisbon is the capital city of Portugal with about 565,000 residents and a population density of 6,600 inhabitants per square kilometre. The town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants. It is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams. Airborne particulate matter limit values are frequently exceeded, with important consequences on air pollution levels and obvious negative impacts on human health. Atmospheric aerosols are known to have in their structure significant amounts of carbonaceous material. The knowledge of the aerosols carbon content, particularly on their several carbon forms (as TC, EC and OC, meaning respectively Total, Elemental and Organic carbon) is often required to provide information for source attribution. In order to assess the vehicles PM input, two sampling campaigns (summer and winter periods) were carried out in 2008 in Lisbon in two contrasting sites, a roadside and an urban background site. Particulate matter was collected in two fractions on quartz fibre filters using Hi-Vol samplers (coarse fraction, 2.5µmwork was performed under Project PAHLIS (Polycyclic Aromatic Hydrocarbons Contamination in Lisbon Urban Atmosphere - PTDC/AMB/65699/2006) financed by "Fundação para a Ciência e a Tecnologia" - FCT. Fátima Mirante acknowledges FCT her PhD grant (SFRH/BD/45473/2008).

  17. Oxidation products of biogenic emissions contribute to nucleation of atmospheric particles.

    Science.gov (United States)

    Riccobono, Francesco; Schobesberger, Siegfried; Scott, Catherine E; Dommen, Josef; Ortega, Ismael K; Rondo, Linda; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Downard, Andrew; Dunne, Eimear M; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hansel, Armin; Junninen, Heikki; Kajos, Maija; Keskinen, Helmi; Kupc, Agnieszka; Kürten, Andreas; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Nieminen, Tuomo; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud P; Santos, Filipe D; Schallhart, Simon; Seinfeld, John H; Sipilä, Mikko; Spracklen, Dominick V; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjö; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Wimmer, Daniela; Carslaw, Kenneth S; Curtius, Joachim; Donahue, Neil M; Kirkby, Jasper; Kulmala, Markku; Worsnop, Douglas R; Baltensperger, Urs

    2014-05-16

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations. Copyright © 2014, American Association for the Advancement of Science.

  18. Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles

    CERN Document Server

    Riccobono, Francesco; Baltensperger, Urs; Worsnop, Douglas R; Curtius, Joachim; Carslaw, Kenneth S; Wimmer, Daniela; Wex, Heike; Weingartner, Ernest; Wagner, Paul E; Vrtala, Aron; Viisanen, Yrjö; Vaattovaara, Petri; Tsagkogeorgas, Georgios; Tomé, Antonio; Stratmann, Frank; Stozhkov, Yuri; Spracklen, Dominick V; Sipilä, Mikko; Praplan, Arnaud P; Petäjä, Tuukka; Onnela, Antti; Nieminen, Tuomo; Mathot, Serge; Makhmutov, Vladimir; Lehtipalo, Katrianne; Laaksonen, Ari; Kvashin, Alexander N.; Kürten, Andreas; Kupc, Agnieszka; Keskinen, Helmi; Kajos, Maija; Junninen, Heikki; Hansel, Armin; Franchin, Alessandro; Flagan, Richard C; Ehrhart, Sebastian; Duplissy, Jonathan; Dunne, Eimear M; Downard, Andrew; David, André; Breitenlechner, Martin; Bianchi, Federico; Amorim, Antonio; Almeida, João; Rondo, Linda; Ortega, Ismael K; Dommen, Josef; Scott, Catherine E; Vrtala, Aron; Santos, Filipe D; Schallhart, Simon; Seinfeld, John H; Sipila, Mikko; Donahue, Neil M; Kirkby, Jasper; Kulmala, Markku

    2014-01-01

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.

  19. Atmospheric aerosol system: An overview

    International Nuclear Information System (INIS)

    Prospero, J.M.; Charlson, R.J.; Mohnen, V.; Jaenicke, R.; Delany, A.C.; Moyers, J.; Zoller, W.; Rahn, K.

    1983-01-01

    Aerosols could play a critical role in many processes which impact on our lives either indirectly (e.g., climate) or directly (e.g., health). However, our ability to assess these possible impacts is constrained by our limited knowledge of the physical and chemical properties of aerosols, both anthropogenic and natural. This deficiency is attributable in part to the fact that aerosols are the end product of a vast array of chemical and physical processes. Consequently, the properties of the aerosol can exhibit a great deal of variability in both time and space. Furthermore, most aerosol studies have focused on measurements of a single aerosol characteristic such as composition or size distribution. Such information is generally not useful for the assessment of impacts because the degree of impact may depend on the integral properties of the aerosol, for example, the aerosol composition as a function of particle size. In this overview we discuss recent work on atmospheric aerosols that illustrates the complex nature of the aerosol chemical and physical system, and we suggest strategies for future research. A major conclusion is that man has had a great impact on the global budgets of certain species, especially sulfur and nitrogen, that play a dominant role in the atmospheric aerosol system. These changes could conceivably affect climate. Large-scale impacts are implied because it has recently been demonstrated that natural and pollutant aerosol episodes can be propagated over great distances. However, at present there is no evidence linking anthropogenic activities with a persistent increase in aerosol concentrations on a global scale. A major problem in assessing man's impact on the atmospheric aerosol system and on global budgets is the absence of aerosol measurements in remote marine and continental areas

  20. Study of the high power laser-metal interactions in the gaseous atmospheres

    Science.gov (United States)

    Lugomer, Stjepan; Bitelli, G.; Stipancic, M.; Jovic, F.

    1994-08-01

    The tantalum and titanium plates were treated by pulsed, high power CO2 laser in the pressurized atmospheres of N2 and O2. Studies performed by the optical microscopy, microhardness measurements, and the auger electron spectroscopy revealed: (1) topographic modification of the surface caused by the temperature field; (2) metal hardening, caused by the laser shock; and (3) alloying/cladding, caused by the chemical reaction between the metal surface and the gaseous atmosphere.

  1. Unusual neurological syndrome induced by atmospheric pressure change.

    Science.gov (United States)

    Ptak, Judy A; Yazinski, Nancy A; Block, Clay A; Buckey, Jay C

    2013-05-01

    We describe a case of a 46-yr-old female who developed hypertension, tachycardia, dysarthria, and leg weakness provoked by pressure changes associated with flying. Typically during the landing phase of flight, she would feel dizzy and note that she had difficulty with speech and leg weakness. After the flight the leg weakness persisted for several days. The symptoms were mitigated when she took a combined alpha-beta blocker (labetalol) prior to the flight. To determine if these symptoms were related to atmospheric pressure change, she was referred for testing in a hyperbaric chamber. She was exposed to elevated atmospheric pressure (maximum 1.2 ATA) while her heart rate and blood pressure were monitored. Within 1 min she developed tachycardia and hypertension. She also quickly developed slurred speech, left arm and leg weakness, and sensory changes in her left leg. She was returned to sea level pressure and her symptoms gradually improved. A full neurological workup has revealed no explanation for these findings. She has no air collections, cysts, or other anatomic findings that could be sensitive to atmospheric pressure change. The pattern is most consistent with a vascular event stimulated by altitude exposure. This case suggests that atmospheric pressure change can produce neurological symptoms, although the mechanism is unknown.

  2. FORMATION OF ORGANIC MOLECULES AND WATER IN WARM DISK ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Najita, Joan R. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Adamkovics, Mate; Glassgold, Alfred E. [Astronomy Department, University of California, Berkeley, CA 94720 (United States)

    2011-12-20

    Observations from Spitzer and ground-based infrared spectroscopy reveal significant diversity in the molecular emission from the inner few AU of T Tauri disks. We explore theoretically the possible origin of this diversity by expanding on our earlier thermal-chemical model of disk atmospheres. We consider how variations in grain settling, X-ray irradiation, accretion-related mechanical heating, and the oxygen-to-carbon ratio can affect the thermal and chemical properties of the atmosphere at 0.25-40 AU. We find that these model parameters can account for many properties of the detected molecular emission. The column density of the warm (200-2000 K) molecular atmosphere is sensitive to grain settling and the efficiency of accretion-related heating, which may account, at least in part, for the large range in molecular emission fluxes that have been observed. The dependence of the atmospheric properties on the model parameters may also help to explain trends that have been reported in the literature between molecular emission strength and mid-infrared color, stellar accretion rate, and disk mass. We discuss whether some of the differences between our model results and the observations (e.g., for water) indicate a role for vertical transport and freezeout in the disk midplane. We also discuss how planetesimal formation in the outer disk (beyond the snowline) may imprint a chemical signature on the inner few AU of the disk and speculate on possible observational tracers of this process.

  3. Generation and characterization of gasoline engine exhaust inhalation exposure atmospheres.

    Science.gov (United States)

    McDonald, Jacob D; Barr, Edward B; White, Richard K; Kracko, Dean; Chow, Judith C; Zielinska, Barbara; Grosjean, Eric

    2008-10-01

    Exposure atmospheres for a rodent inhalation toxicology study were generated from the exhaust of a 4.3-L gasoline engine coupled to a dynamometer and operated on an adapted California Unified Driving Cycle. Exposure levels were maintained at three different dilution rates. One chamber at the lowest dilution had particles removed by filtration. Each exposure atmosphere was characterized for particle mass, particle number, particle size distribution, and detailed chemical speciation. The majority of the mass in the exposure atmospheres was gaseous carbon monoxide, nitrogen oxides, and volatile organics, with small amounts of particle-bound carbon/ions and metals. The atmospheres varied according to the cycle, with the largest spikes in volatile organic and inorganic species shown during the "cold start" portion of the cycle. Ammonia present from the exhaust and rodents interacted with the gasoline exhaust to form secondary inorganic particles, and an increase in exhaust resulted in higher proportions of secondary inorganics as a portion of the total particle mass. Particle size had a median of 10-20 nm by number and approximately 150 nm by mass. Volatile organics matched the composition of the fuel, with large proportions of aliphatic and aromatic hydrocarbons coupled to low amounts of oxygenated organics. A new measurement technique revealed organics reacting with nitrogen oxides have likely resulted in measurement bias in previous studies of combustion emissions. Identified and measured particle organic species accounted for about 10% of total organic particle mass and were mostly aliphatic acids and polycyclic aromatic hydrocarbons.

  4. FORMATION OF ORGANIC MOLECULES AND WATER IN WARM DISK ATMOSPHERES

    International Nuclear Information System (INIS)

    Najita, Joan R.; Ádámkovics, Máté; Glassgold, Alfred E.

    2011-01-01

    Observations from Spitzer and ground-based infrared spectroscopy reveal significant diversity in the molecular emission from the inner few AU of T Tauri disks. We explore theoretically the possible origin of this diversity by expanding on our earlier thermal-chemical model of disk atmospheres. We consider how variations in grain settling, X-ray irradiation, accretion-related mechanical heating, and the oxygen-to-carbon ratio can affect the thermal and chemical properties of the atmosphere at 0.25-40 AU. We find that these model parameters can account for many properties of the detected molecular emission. The column density of the warm (200-2000 K) molecular atmosphere is sensitive to grain settling and the efficiency of accretion-related heating, which may account, at least in part, for the large range in molecular emission fluxes that have been observed. The dependence of the atmospheric properties on the model parameters may also help to explain trends that have been reported in the literature between molecular emission strength and mid-infrared color, stellar accretion rate, and disk mass. We discuss whether some of the differences between our model results and the observations (e.g., for water) indicate a role for vertical transport and freezeout in the disk midplane. We also discuss how planetesimal formation in the outer disk (beyond the snowline) may imprint a chemical signature on the inner few AU of the disk and speculate on possible observational tracers of this process.

  5. Ionization Efficiency in the Dayside Martian Upper Atmosphere

    Science.gov (United States)

    Cui, J.; Wu, X.-S.; Xu, S.-S.; Wang, X.-D.; Wellbrock, A.; Nordheim, T. A.; Cao, Y.-T.; Wang, W.-R.; Sun, W.-Q.; Wu, S.-Q.; Wei, Y.

    2018-04-01

    Combining the Mars Atmosphere and Volatile Evolution measurements of neutral atmospheric density, solar EUV/X-ray flux, and differential photoelectron intensity made during 240 nominal orbits, we calculate the ionization efficiency, defined as the ratio of the secondary (photoelectron impact) ionization rate to the primary (photon impact) ionization rate, in the dayside Martian upper atmosphere under a range of solar illumination conditions. Both the CO2 and O ionization efficiencies tend to be constant from 160 km up to 250 km, with respective median values of 0.19 ± 0.03 and 0.27 ± 0.04. These values are useful for fast calculation of the ionization rate in the dayside Martian upper atmosphere, without the need to construct photoelectron transport models. No substantial diurnal and solar cycle variations can be identified, except for a marginal trend of reduced ionization efficiency approaching the terminator. These observations are favorably interpreted by a simple scenario with ionization efficiencies, as a first approximation, determined by a comparison between relevant cross sections. Our analysis further reveals a connection between regions with strong crustal magnetic fields and regions with high ionization efficiencies, which are likely indicative of more efficient vertical transport of photoelectrons near magnetic anomalies.

  6. Atmospheric oxidation mechanism of toluene.

    Science.gov (United States)

    Wu, Runrun; Pan, Shanshan; Li, Yun; Wang, Liming

    2014-06-26

    The atmospheric oxidation mechanism of toluene initiated by OH radical addition is investigated by quantum chemistry calculations at M06-2X, G3MP2-RAD, and ROCBS-QB3 levels and by kinetics calculation by using transition state theory and unimolecular reaction theory coupled with master equation (RRKM-ME). The predicted branching ratios are 0.15, 0.59, 0.05, and 0.14 for OH additions to ipso, ortho, meta, and para positions (forming R1-R4 adducts), respectively. The fate of R2, R4, and R1 is investigated in detail. In the atmosphere, R2 reacts with O2 either by irreversible H-abstraction to form o-cresol (36%), or by reversible recombination to R2-1OO-syn and R2-3OO-syn, which subsequently cyclize to bicyclic radical R2-13OO-syn (64%). Similarly, R4 reacts with O2 with branching ratios of 61% for p-cresol and 39% for R4-35OO-syn, while reaction of R1 and O2 leads to R1-26OO-syn. RRKM-ME calculations show that the reactions of R2/R4 with O2 have reached their high-pressure limits at 760 Torr and the formation of R2-16O-3O-s is only important at low pressure, i.e., 5.4% at 100 Torr. The bicyclic radicals (R2-13OO-syn, R4-35OO-syn, and R1-26OO-syn) will recombine with O2 to produce bicyclic alkoxy radicals after reacting with NO. The bicyclic alkoxy radicals would break the ring to form products methylglyoxal/glyoxal (MGLY/GLY) and their corresponding coproducts butenedial/methyl-substituted butenedial as proposed in earlier studies. However, a new reaction pathway is found for the bicyclic alkoxy radicals, leading to products MGLY/GLY and 2,3-epoxybutandial/2-methyl-2,3-epoxybutandial. A new mechanism is proposed for the atmospheric oxidation mechanism of toluene based on current theoretical and previous theoretical and experimental results. The new mechanism predicts much lower yield of GLY and much higher yield of butenedial than other atmospheric models and recent experimental measurements. The new mechanism calls for detection of proposed products 2

  7. Chemical characterization of atmospheric particles

    International Nuclear Information System (INIS)

    Adams, F.

    2002-01-01

    In the characterisation of complex environmental materials such as atmospheric particulate matter, analytical specificity is required to account for the many dimensions of information present in the sample. These dimensions include size, morphology, elemental composition, inorganic and organic chemical speciation, all to be performed on either single particles or on the population (or bulk sample) basis. Various techniques were developed for such measurements, including a number of bulk analysis procedures, methodologies for microscopical analysis of individual particles, and a variety of procedures for organic/inorganic chemical speciation. (author)

  8. Outer scale of atmospheric turbulence

    Science.gov (United States)

    Lukin, Vladimir P.

    2005-10-01

    In the early 70's, the scientists in Italy (A.Consortini, M.Bertolotti, L.Ronchi), USA (R.Buser, Ochs, S.Clifford) and USSR (V.Pokasov, V.Lukin) almost simultaneously discovered the phenomenon of deviation from the power law and the effect of saturation for the structure phase function. During a period of 35 years we have performed successively the investigations of the effect of low-frequency spectral range of atmospheric turbulence on the optical characteristics. The influence of the turbulence models as well as a outer scale of turbulence on the characteristics of telescopes and systems of laser beam formations has been determined too.

  9. White dwarf stars with chemically stratified atmospheres

    Science.gov (United States)

    Muchmore, D.

    1982-01-01

    Recent observations and theory suggest that some white dwarfs may have chemically stratified atmospheres - thin layers of hydrogen lying above helium-rich envelopes. Models of such atmospheres show that a discontinuous temperature inversion can occur at the boundary between the layers. Model spectra for layered atmospheres at 30,000 K and 50,000 K tend to have smaller decrements at 912 A, 504 A, and 228 A than uniform atmospheres would have. On the basis of their continuous extreme ultraviolet spectra, it is possible to distinguish observationally between uniform and layered atmospheres for hot white dwarfs.

  10. The atmosphere and ocean: A physical introduction

    International Nuclear Information System (INIS)

    Wells, N.

    1986-01-01

    The book's contents are: The Earth within the solar system. Composition and physical properties of the ocean and atmosphere. Radiation, temperature and stability. Water in the atmosphere. Global budgets of heat, water and salt. Observations of winds and currents. The influence of the Earth's rotation on fluid motion. Waves and tides. Energy transfer in the ocean-atmosphere system. Climate variability and predictability. The atmosphere and ocean are two different environmental systems, yet both are interdependent, interacting and exchanging energy, heat and matter. This book attempts to bring the study of the atmosphere and ocean together. It is a descriptive account of physical properties, exploring their common bases, similarities, interactions and fundamental differences

  11. Atmospheric Physics Background – Methods – Trends

    CERN Document Server

    2012-01-01

    On the occasion of the 50th anniversary of the Institute of Atmospheric Physics of the German Aerospace Center (DLR), this book presents more than 50 chapters highlighting results of the institute’s research. The book provides an up-to-date, in-depth survey across the entire field of atmospheric science, including atmospheric dynamics, radiation, cloud physics, chemistry, climate, numerical simulation, remote sensing, instruments and measurements, as well as atmospheric acoustics. The authors have provided a readily comprehensible and self-contained presentation of the complex field of atmospheric science. The topics are of direct relevance for aerospace science and technology. Future research challenges are identified.

  12. Atmospheric gravity waves in the Red Sea: a new hotspot

    KAUST Repository

    Magalhaes, J. M.

    2011-02-03

    The region of the Middle East around the Red Sea (between 32° E and 44° E longitude and 12° N and 28° N latitude) is a currently undocumented hotspot for atmospheric gravity waves (AGWs). Satellite imagery shows evidence that this region is prone to relatively high occurrence of AGWs compared to other areas in the world, and reveals the spatial characteristics of these waves. The favorable conditions for wave propagation in this region are illustrated with three typical cases of AGWs propagating in the lower troposphere over the sea. Using weakly nonlinear long wave theory and the observed characteristic wavelengths we obtain phase speeds which are consistent with those observed and typical for AGWs, with the Korteweg-de Vries theory performing slightly better than Benjamin-Davis-Acrivos-Ono theory as far as phase speeds are concerned. ERS-SAR and Envisat-ASAR satellite data analysis between 1993 and 2008 reveals signatures consistent with horizontally propagating large-scale internal waves. These signatures cover the entire Red Sea and are more frequently observed between April and September, although they also occur during the rest of the year. The region\\'s (seasonal) propagation conditions for AGWs, based upon average vertical atmospheric stratification profiles suggest that many of the signatures identified in the satellite images are atmospheric internal waves. © Author(s) 2011.

  13. Atmospheric sciences annual progress report, 1974

    International Nuclear Information System (INIS)

    Tucker, W.D.

    1975-11-01

    Activities in atmospheric sciences in the Department of Applied Science at Brookhaven National Laboratory carried out during 1974 are described. Included are contributions from the Meteorology, Atmospheric Diagnostics, Atmospheric Chemistry Research, and Atmospheric Instrumentation Groups. Programs in Meteorology reported on include diffusion from an off-shore source, plume dynamics studies, modeling of coastal effects on wind and temperature fields and pollutant distributions, effects of indoor shelter on inhalation of airborne radionuclides, chemical-dynamical interactions, techniques for determining acid-rain impact upon the ecology of the eastern U.S., and climatology. Work under Atmospheric Chemistry Research was concentrated on atmospheric aerosol studies, including formation by free radical and neutral association reactions, identification of reactive systems leading to aerosol formation, growth of sodium aerosols under atmospheric conditions and clustering reactions. Atmospheric Diagnostics presents work on field sampling and analytical technology for atmospheric pollutants, airborne sampling systems, atmospheric sulfate particulates methodology, and on a pyroturbidometric method for particulate sulfate discrimination and determination. Methodology for the use of sulfur hexafluoride in field tracer studies is discussed under Atmospheric Instrumentation. A list of publications is included

  14. Regional Ecosystem-Atmosphere CO2 Exchange Via Atmospheric Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Davis, K J; Richardson, S J; Miles, N L

    2007-03-07

    Inversions of atmospheric CO2 mixing ratio measurements to determine CO2 sources and sinks are typically limited to coarse spatial and temporal resolution. This limits our ability to evaluate efforts to upscale chamber- and stand-level CO2 flux measurements to regional scales, where coherent climate and ecosystem mechanisms govern the carbon cycle. As a step towards the goal of implementing atmospheric budget or inversion methodology on a regional scale, a network of five relatively inexpensive CO2 mixing ratio measurement systems was deployed on towers in northern Wisconsin. Four systems were distributed on a circle of roughly 150-km radius, surrounding one centrally located system at the WLEF tower near Park Falls, WI. All measurements were taken at a height of 76 m AGL. The systems used single-cell infrared CO2 analyzers (Licor, model LI-820) rather than the siginificantly more costly two-cell models, and were calibrated every two hours using four samples known to within ± 0.2 ppm CO2. Tests prior to deployment in which the systems sampled the same air indicate the precision of the systems to be better than ± 0.3 ppm and the accuracy, based on the difference between the daily mean of one system and a co-located NOAA-ESRL system, is consistently better than ± 0.3 ppm. We demonstrate the utility of the network in two ways. We interpret regional CO2 differences using a Lagrangian parcel approach. The difference in the CO2 mixing ratios across the network is at least 2-3 ppm, which is large compared to the accuracy and precision of the systems. Fluxes estimated assuming Lagrangian parcel transport are of the same sign and magnitude as eddy-covariance flux measurements at the centrally-located WLEF tower. These results indicate that the network will be useful in a full inversion model. Second, we present a case study involving a frontal passage through the region. The progression of a front across the network is evident; changes as large as four ppm in one minute

  15. Thermal Band Atmospheric Correction Using Atmospheric Profiles Derived from Global Positioning System Radio Occultation and the Atmospheric Infrared Sounder

    Science.gov (United States)

    Pagnutti, Mary; Holekamp, Kara; Stewart, Randy; Vaughan, Ronald D.

    2006-01-01

    This Rapid Prototyping Capability study explores the potential to use atmospheric profiles derived from GPS (Global Positioning System) radio occultation measurements and by AIRS (Atmospheric Infrared Sounder) onboard the Aqua satellite to improve surface temperature retrieval from remotely sensed thermal imagery. This study demonstrates an example of a cross-cutting decision support technology whereby NASA data or models are shown to improve a wide number of observation systems or models. The ability to use one data source to improve others will be critical to the GEOSS (Global Earth Observation System of Systems) where a large number of potentially useful systems will require auxiliary datasets as input for decision support. Atmospheric correction of thermal imagery decouples TOA radiance and separates surface emission from atmospheric emission and absorption. Surface temperature can then be estimated from the surface emission with knowledge of its emissivity. Traditionally, radiosonde sounders or atmospheric models based on radiosonde sounders, such as the NOAA (National Oceanic & Atmospheric Administration) ARL (Air Resources Laboratory) READY (Real-time Environmental Application and Display sYstem), provide the atmospheric profiles required to perform atmospheric correction. Unfortunately, these types of data are too spatially sparse and too infrequently taken. The advent of high accuracy, global coverage, atmospheric data using GPS radio occultation and AIRS may provide a new avenue for filling data input gaps. In this study, AIRS and GPS radio occultation derived atmospheric profiles from the German Aerospace Center CHAMP (CHAllenging Minisatellite Payload), the Argentinean Commission on Space Activities SAC-C (Satellite de Aplicaciones Cientificas-C), and the pair of NASA GRACE (Gravity Recovery and Climate Experiment) satellites are used as input data in atmospheric radiative transport modeling based on the MODTRAN (MODerate resolution atmospheric

  16. Infrared observations of planetary atmospheres

    International Nuclear Information System (INIS)

    Orton, G.S.; Baines, K.H.; Bergstralh, J.T.

    1988-01-01

    The goal of this research in to obtain infrared data on planetary atmospheres which provide information on several aspects of structure and composition. Observations include direct mission real-time support as well as baseline monitoring preceding mission encounters. Besides providing a broader information context for spacecraft experiment data analysis, observations will provide the quantitative data base required for designing optimum remote sensing sequences and evaluating competing science priorities. In the past year, thermal images of Jupiter and Saturn were made near their oppositions in order to monitor long-term changes in their atmospheres. Infrared images of the Jovian polar stratospheric hot spots were made with IUE observations of auroral emissions. An exploratory 5-micrometer spectrum of Uranus was reduced and accepted for publication. An analysis of time-variability of temperature and cloud properties of the Jovian atomsphere was made. Development of geometric reduction programs for imaging data was initiated for the sun workstation. Near-infrared imaging observations of Jupiter were reduced and a preliminary analysis of cloud properties made. The first images of the full disk of Jupiter with a near-infrared array camera were acquired. Narrow-band (10/cm) images of Jupiter and Saturn were obtained with acousto-optical filters

  17. Atmospheric diffusion of large clouds

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, T. V. [Univ. of California, Lawrence Radiation Lab., Livermore, California (United States)

    1967-07-01

    Clouds of pollutants travel within a coordinate system that is fixed to the earth's surface, and they diffuse and grow within a coordinate system fixed to the cloud's center. This paper discusses an approach to predicting the cloud's properties, within the latter coordinate system, on space scales of a few hundred meters to a few hundred kilometers and for time periods of a few days. A numerical cloud diffusion model is presented which starts with a cloud placed arbitrarily within the troposphere. Similarity theories of atmospheric turbulence are used to predict the horizontal diffusivity as a function of initial cloud size, turbulent atmospheric dissipation, and time. Vertical diffusivity is input as a function of time and height. Therefore, diurnal variations of turbulent diffusion in the boundary layer and effects of temperature inversions, etc. can be modeled. Nondiffusive cloud depletion mechanisms, such as dry deposition, washout, and radioactive decay, are also a part of this numerical model. An effluent cloud, produced by a reactor run at the Nuclear Rocket Development Station, Nevada, is discussed in this paper. Measurements on this cloud, for a period of two days, are compared to calculations with the above numerical cloud diffusion model. In general, there is agreement. within a factor of two, for airborne concentrations, cloud horizontal area, surface air concentrations, and dry deposition as airborne concentration decreased by seven orders of magnitude during the two-day period. (author)

  18. Atmospheric Release Advisory Capability (ARAC)

    International Nuclear Information System (INIS)

    Dickerson, M.H.

    1975-01-01

    The chief purpose of ARAC data acquisition program is to provide site officials, who are responsible for ensuring maximum health protection for the endangered site personnel and public, with estimates of the effects of atmospheric releases of hazardous material as rapidly and accurately as possible. ARAC is in the initial stages of being implemented and is therefore susceptible to changes before it reaches its final form. However the concept of ARAC is fully developed and was successfully demonstrated during a feasibility study conducted in June 1974, as a joint effort between the Savannah River Laboratory (SRL) and Lawrence Livermore Laboratory (LLL). Additional tests between SRL and LLL are scheduled for December 1975. While the immediate goal is the application of ARAC to assist a limited number of ERDA sites, the system is designed with sufficient flexibility to permit expanding the service to a large number of sites. Success in ARAC application should provide nuclear facilities with a means to handle better the urgent questions concerning the potential accidental hazards from atmospheric releases in addition to providing the sites with a capability to assess the effort of their normal operations

  19. Atmospheric particulate pollution in Kenitra (Morocco)

    International Nuclear Information System (INIS)

    Zghaid, Mustapha; Noack, Yves; Boukla, Moussa; Benyaich, Fouad

    2009-01-01

    Cities of Morocco are exposed to a high atmospheric particulate pollution due to automobile traffic, industrialization, but also to soil dusts (in relation with aridity and desert proximity). Monitoring networks and data about air pollution still rare. The present study is a preliminary work about particulate and heavy metals pollution in Kenitra city. Aerosols had been collected with a PM10 sampler (Partisol), a dichotomous sampler (P M2.5 and P M2.5-10 fractions) and stacked filter unit (Gent type) with a fine fraction (below 2.5 um) and a coarse fraction. In summer, the average PM10 concentration is near 80 u g/N m 3 , above the EEC rule and OMS recommendations, but similar to some other african towns. The ratio P M2.5/PM 10 is low (below 0.5), with seasonal variation in relation with meteorology. The lead and nickel concentrations are also very low, in relation with the use of leaded gasoline and the oldness of many vehicles. This preliminary work reveals high levels of pollution (especially PM10, Pb and Ni) in the town of Kenitra. The major sources are traffic, soil dusts and resuspension of deposited particles. It is necessary to develop monitoring network and sanitary and and environmental impact studies in these cities [fr

  20. Atmospheric emissions from road transportation in India

    International Nuclear Information System (INIS)

    Baidya, S.; Borken-Kleefeld, J.

    2009-01-01

    India has become one of the biggest emitters of atmospheric pollutants from the road transportation sector globally. Here we present an up-to-date inventory of the exhaust emissions of ten species. This inventory has been calculated bottom-up from the vehicle mileage, differentiating by seven vehicle categories, four age/technology layers and three fuel types each, for the seven biggest cities as well as for the whole nation. The age composition of the rolling fleet has been carefully modelled, deducting about one quarter of vehicles still registered but actually out-of-service. The vehicle mileage is calibrated to the national fuel consumption which is essential to limit uncertainties. Sensitivity analyses reveal the primary impact of the emission factors and the secondary influence of vehicle mileage and stock composition on total emissions. Emission estimates since 1980 are reviewed and qualified. A more comprehensive inspection and maintenance is essential to limit pollutant emissions; this must properly include commercial vehicles. They are also the most important vehicle category to address when fuel consumption and CO 2 emissions shall be contained. (author)

  1. Large wind ripples on Mars: A record of atmospheric evolution

    Science.gov (United States)

    Lapotre, M. G. A.; Ewing, R. C.; Lamb, M. P.; Fischer, W. W.; Grotzinger, J. P.; Rubin, D. M.; Lewis, K. W.; Ballard, M. J.; Day, M.; Gupta, S.; Banham, S. G.; Bridges, N. T.; Des Marais, D. J.; Fraeman, A. A.; Grant, J. A.; Herkenhoff, K. E.; Ming, D. W.; Mischna, M. A.; Rice, M. S.; Sumner, D. A.; Vasavada, A. R.; Yingst, R. A.

    2016-07-01

    Wind blowing over sand on Earth produces decimeter-wavelength ripples and hundred-meter- to kilometer-wavelength dunes: bedforms of two distinct size modes. Observations from the Mars Science Laboratory Curiosity rover and the Mars Reconnaissance Orbiter reveal that Mars hosts a third stable wind-driven bedform, with meter-scale wavelengths. These bedforms are spatially uniform in size and typically have asymmetric profiles with angle-of-repose lee slopes and sinuous crest lines, making them unlike terrestrial wind ripples. Rather, these structures resemble fluid-drag ripples, which on Earth include water-worked current ripples, but on Mars instead form by wind because of the higher kinematic viscosity of the low-density atmosphere. A reevaluation of the wind-deposited strata in the Burns formation (about 3.7 billion years old or younger) identifies potential wind-drag ripple stratification formed under a thin atmosphere.

  2. Large wind ripples on Mars: A record of atmospheric evolution

    Science.gov (United States)

    Lapotre, M G; Ewing, R C; Lamb, M P; Fischer, W W; Grotzinger, J P; Rubin, D M; Lewis, K W; Ballard, M; Day, Mitch D.; Gupta, S.; Banham, S G; Bridges, N T; Des Marais, D J; Fraeman, A A; Grant, J A; Herkenhoff, Kenneth E.; Ming, D W; Mischna, M A; Rice, M S; Sumner, D A; Vasavada, A R; Yingst, R A

    2016-01-01

    Wind blowing over sand on Earth produces decimeter-wavelength ripples and hundred-meter– to kilometer-wavelength dunes: bedforms of two distinct size modes. Observations from the Mars Science Laboratory Curiosity rover and the Mars Reconnaissance Orbiter reveal that Mars hosts a third stable wind-driven bedform, with meter-scale wavelengths. These bedforms are spatially uniform in size and typically have asymmetric profiles with angle-of-repose lee slopes and sinuous crest lines, making them unlike terrestrial wind ripples. Rather, these structures resemble fluid-drag ripples, which on Earth include water-worked current ripples, but on Mars instead form by wind because of the higher kinematic viscosity of the low-density atmosphere. A reevaluation of the wind-deposited strata in the Burns formation (about 3.7 billion years old or younger) identifies potential wind-drag ripple stratification formed under a thin atmosphere.

  3. Atmospheric pollutants monitoring by analysis of epiphytic lichens

    International Nuclear Information System (INIS)

    Fuga, Alessandra; Saiki, Mitiko; Marcelli, Marcelo P.; Saldiva, Paulo H.N.

    2008-01-01

    The Canoparmelia texana epiphytic lichenized fungi was used to monitor atmospheric pollution in the Sao Paulo metropolitan region, SP, Brazil. The cluster analysis applied to the element concentration values confirmed the site groups of different levels of pollution due to industrial and vehicular emissions. In the distribution maps of element concentrations, higher concentrations of Ba and Mn were observed in the vicinity of industries and of a petrochemical complex. The highest concentration of Co found in lichens from the Sao Miguel Paulista site is due to the emissions from a metallurgical processing plant that produces this element. For Br and Zn, the highest concentrations could be associated both to vehicular and industrial emissions. Exploratory analyses revealed that the accumulation of toxic elements in C. texana may be of use in evaluating the human risk of cardiopulmonary mortality due to prolonged exposure to ambient levels of air pollution. - Canoparmelia texana lichenized fungi is a valuable biomonitor for atmospheric pollution

  4. Electron microscopy of atmospheric particles

    Science.gov (United States)

    Huang, Po-Fu

    Electron microscopy coupled with energy dispersive spectrometry (EM/EDS) is a powerful tool for single particle analysis. However, the accuracy with which atmospheric particle compositions can be quantitatively determined by EDS is often hampered by substrate-particle interactions, volatilization losses in the low pressure microscope chamber, electron beam irradiation and use of inaccurate quantitation factors. A pseudo-analytical solution was derived to calculate the temperature rise due to the dissipation of the electron energy on a particle-substrate system. Evaporative mass loss for a spherical cap-shaped sulfuric acid particle resting on a thin film supported by a TEM grid during electron beam impingement has been studied. Measured volatilization rates were found to be in very good agreement with theoretical predictions. The method proposed can also be used to estimate the vapor pressure of a species by measuring the decay of X-ray intensities. Several types of substrates were studied. We found that silver-coated silicon monoxide substrates give carbon detection limits comparable to commercially available substrates. An advantage of these substrates is that the high thermal conductivity of the silver reduces heating due to electron beam impingement. In addition, exposure of sulfuric acid samples to ammonia overnight substantially reduces sulfur loss in the electron beam. Use of size-dependent k-factors determined from particles of known compositions shows promise for improving the accuracy of atmospheric particle compositions measured by EM/EDS. Knowledge accumulated during the course of this thesis has been used to analyze atmospheric particles (Minneapolis, MN) selected by the TDMA and collected by an aerodynamic focusing impactor. 'Less' hygroscopic particles, which do not grow to any measurable extent when humidified to ~90% relative humidity, included chain agglomerates, spheres, flakes, and irregular shapes. Carbon was the predominant element detected in

  5. Titan's Atmospheric Dynamics and Meteorology

    Science.gov (United States)

    Flasar, F. M.; Baines, K. H.; Bird, M. K.; Tokano, T.; West, R. A.

    2008-01-01

    Titan, after Venus, is the second example of an atmosphere with a global cyclostrophic circulation in the solar system, but a circulation that has a strong seasonal modulation in the middle atmosphere. Direct measurement of Titan's winds, particularly observations tracking the Huygens probe at 10degS, indicate that the zonal winds are generally in the sense of the satellites rotation. They become cyclostrophic approx. 35 km above the surface and generally increase with altitude, with the exception of a sharp minimum centered near 75 km, where the wind velocity decreases to nearly zero. Zonal winds derived from the temperature field retrieved from Cassini measurements, using the thermal wind equation, indicate a strong winter circumpolar vortex, with maximum winds at mid northern latitudes of 190 ms-' near 300 km. Above this level, the vortex decays. Curiously, the zonal winds and temperatures are symmetric about a pole that is offset from the surface pole by approx.4 degrees. The cause of this is not well understood, but it may reflect the response of a cyclostrophic circulation to the offset between the equator, where the distance to the rotation axis is greatest, and the solar equator. The mean meridional circulation can be inferred from the temperature field and the meridional distribution of organic molecules and condensates and hazes. Both the warm temperatures in the north polar region near 400 km and the enhanced concentration of several organic molecules suggests subsidence there during winter and early spring. Stratospheric condensates are localized at high northern latitudes, with a sharp cut-off near 50degN. Titan's winter polar vortex appears to share many of the same characteristics of winter vortices on Earth-the ozone holes. Global mapping of temperatures, winds, and composition in he troposphere, by contrast, is incomplete. The few suitable discrete clouds that have bee found for tracking indicate smaller velocities than aloft, consistent with the

  6. Revealed preference with limited consideration

    NARCIS (Netherlands)

    Demuynck, T.; Seel, C.

    2014-01-01

    We derive revealed preference tests for models where individuals use consideration sets to simplify their consumption problem. Our basic test provides necessary and sufficient conditions for consistency of observed choices with the existence of consideration set restrictions. The same conditions can

  7. Decision Making and Revealed Preference

    DEFF Research Database (Denmark)

    de la Rosa, Leonidas Enrique

    If our decision-making processes are to some extent shaped by evolutionary pressures and our environment is different from that to which we adapted, some of our choices will not be in our best interest. But revealed preference is the only tool that we have so far to conduct a normative analysis...

  8. Direct and indirect atmospheric deposition of PCBs to the Delaware River watershed.

    Science.gov (United States)

    Totten, Lisa A; Panangadan, Maya; Eisenreich, Steven J; Cavallo, Gregory J; Fikslin, Thomas J

    2006-04-01

    Atmospheric deposition can be an important source of PCBs to aquatic ecosystems. To develop the total maximum daily load (TMDL) for polychlorinated biphenyls (PCBs) for the tidal Delaware River (water-quality Zones 2-5), estimates of the loading of PCBs to the river from atmospheric deposition were generated from seven air-monitoring sites along the river. This paper presents the atmospheric PCB data from these sites, estimates direct atmospheric deposition fluxes, and assesses the importance of atmospheric deposition relative to other sources of PCBs to the river. Also, the relationship between indirect atmospheric deposition and PCB loads from minor tributaries to the Delaware River is discussed. Data from these sites revealed high atmospheric PCB concentrations in the Philadelphia/Camden urban area and lower regional background concentrations in the more remote areas. Wet, dry particle, and gaseous absorption deposition are estimated to contribute about 0.6, 1.8, and 6.5 kg year-(-1) sigmaPCBs to the River, respectively, exceeding the TMDL of 0.139 kg year(-1) by more than an order of magnitude. Penta-PCB watershed fluxes were obtained by dividing the tributary loads by the watershed area. The lowest of these watershed fluxes are less than approximately 1 ng m(-2) day(-1) for penta-PCB and probably indicates pristine watersheds in which PCB loads are dominated by atmospheric deposition. In these watersheds, the pass-through efficiency of PCBs is estimated to be on the order of 1%.

  9. Modelling land surface - atmosphere interactions

    DEFF Research Database (Denmark)

    Rasmussen, Søren Højmark

    representation of groundwater in the hydrological model is found to important and this imply resolving the small river valleys. Because, the important shallow groundwater is found in the river valleys. If the model does not represent the shallow groundwater then the area mean surface flux calculation......The study is investigates modelling of land surface – atmosphere interactions in context of fully coupled climatehydrological model. With a special focus of under what condition a fully coupled model system is needed. Regional climate model inter-comparison projects as ENSEMBLES have shown bias...... by the hydrological model is found to be insensitive to model resolution. Furthermore, this study highlights the effect of bias precipitation by regional climate model and it implications for hydrological modelling....

  10. Atmospheric pollution in our environment

    International Nuclear Information System (INIS)

    Tanvir, G.

    1986-01-01

    Air pollution is associated with all the activities of humans. It is becoming a serious problem in coming years so it is relevant to find out how seriously our atmosphere is being polluted and how this pollution affects human and plant life in our environment. Not only the human activities are the source of our pollution but nature causes more pollution. Air pollution that is due to the pressure of foreign substances in air, effects the quality and concentration of air substances. It is not only injurious to property, but also to vegetation and animal life. Air pollution is one of our most serious environmental problems. The sources vary from smoke-stacks and automobiles to noise and foreon containing aerosols. (orig./A.B.)

  11. VIRTUAL AND PHYSICAL ARCHITECTURAL ATMOSPHERE

    DEFF Research Database (Denmark)

    Hermund, Anders; Klint, Lars

    2016-01-01

    This study, of the similarities between the perception of architectural space experienced in physical space conditions and in Virtual Reality, intents to clarify to what extend subjective and objective attributes of architectural space can be conveyed through a direct use of Building Information...... Models in Virtual Reality. 60 test persons experienced a specific test space as either a physical or a virtual environment, while data from their experiences was collected through a quantitative/qualitative questionnaire. The overall conclusion, from this phase of the study, is that even a simple BIM...... model through HMD VR can convey rather precise information about both subjective and objective experiences of architectural space, ambience and atmosphere. Next phase of the study will include eye-tracking data from the two scenarios....

  12. Imaging spectrometers for atmosphere monitoring

    Science.gov (United States)

    Reinert, Thido; Bovensmann, Heinrich; Münzenmayer, Ralf; Weiss, Stefan; Posselt, Winfried

    2017-11-01

    Atmospheric monitoring missions aim at products like O3, H2O, NO2, SO2, BrO, CH4, CO, CO2 as well as aerosols and cloud information. Depending on the application area (Ozone Monitoring, Green House Gas Monitoring, Tropospheric Composition and Air Quality, Chemistry Climate Interaction etc.) total or tropospheric columns as well as profile information is required. The user community of these data as well as their central requirements w.r.t. the payload aspects will be described. A large range of relevant passive instrument types is available, in particular imaging spectrometer, sounder and polarisation measuring systems in the UV-VIS, SWIR and TIR spectral range. Differences between instruments for dedicated missions are highlighted and evolution of requirements is explained, also in comparison with relevant existing instrumentation partly in orbit today. Aspects of technology roadmaps for instrument implementation as well as synergetic effects of instrument combinations and according mission scopes are discussed.

  13. The black hole quantum atmosphere

    Science.gov (United States)

    Dey, Ramit; Liberati, Stefano; Pranzetti, Daniele

    2017-11-01

    Ever since the discovery of black hole evaporation, the region of origin of the radiated quanta has been a topic of debate. Recently it was argued by Giddings that the Hawking quanta originate from a region well outside the black hole horizon by calculating the effective radius of a radiating body via the Stefan-Boltzmann law. In this paper we try to further explore this issue and end up corroborating this claim, using both a heuristic argument and a detailed study of the stress energy tensor. We show that the Hawking quanta originate from what might be called a quantum atmosphere around the black hole with energy density and fluxes of particles peaked at about 4 MG, running contrary to the popular belief that these originate from the ultra high energy excitations very close to the horizon. This long distance origin of Hawking radiation could have a profound impact on our understanding of the information and transplanckian problems.

  14. The black hole quantum atmosphere

    Directory of Open Access Journals (Sweden)

    Ramit Dey

    2017-11-01

    Full Text Available Ever since the discovery of black hole evaporation, the region of origin of the radiated quanta has been a topic of debate. Recently it was argued by Giddings that the Hawking quanta originate from a region well outside the black hole horizon by calculating the effective radius of a radiating body via the Stefan–Boltzmann law. In this paper we try to further explore this issue and end up corroborating this claim, using both a heuristic argument and a detailed study of the stress energy tensor. We show that the Hawking quanta originate from what might be called a quantum atmosphere around the black hole with energy density and fluxes of particles peaked at about 4MG, running contrary to the popular belief that these originate from the ultra high energy excitations very close to the horizon. This long distance origin of Hawking radiation could have a profound impact on our understanding of the information and transplanckian problems.

  15. Atmospheric muons reconstruction with Antares

    International Nuclear Information System (INIS)

    Melissas, M.

    2007-09-01

    The ANTARES collaboration is building a neutrino telescope in the Mediterranean Sea. This detector contains 900 photomultiplier tubes, dispatched on 12 lines, in order to detect Cerenkov light from muon induced by neutrino interactions in the the vicinity of the detector. Currently the first 5 lines have been deployed. A first task consists in studying the stability of the detector calibration, which is a necessary step to understand the detector response. Then we studied optical properties of water, for this we developed a reconstruction method dedicated to LED Beacon. The extracted parameters are compatible with earlier measurements. A quality criteria to reject badly reconstructed track has been developed based on the likelihood of the tracks fit versus point fit. This has been applied to real data and a preliminary analysis of atmospheric muons with a 5-lines detector is performed. (author)

  16. CONTRIBUTION FOR MINING ATMOSPHERE CALCULATION

    Directory of Open Access Journals (Sweden)

    Franica Trojanović

    1989-12-01

    Full Text Available Humid air is an unavoidable feature of mining atmosphere, which plays a significant role in defining the climate conditions as well as permitted circumstances for normal mining work. Saturated humid air prevents heat conduction from the human body by means of evaporation. Consequently, it is of primary interest in the mining practice to establish the relative air humidity either by means of direct or indirect methods. Percentage of water in the surrounding air may be determined in various procedures including tables, diagrams or particular calculations, where each technique has its specific advantages and disadvantages. Classical calculation is done according to Sprung's formula, in which case partial steam pressure should also be taken from the steam table. The new method without the use of diagram or tables, established on the functional relation of pressure and temperature on saturated line, is presented here for the first time (the paper is published in Croatian.

  17. Stochastic models for atmospheric dispersion

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2003-01-01

    Simple stochastic differential equation models have been applied by several researchers to describe the dispersion of tracer particles in the planetary atmospheric boundary layer and to form the basis for computer simulations of particle paths. To obtain the drift coefficient, empirical vertical...... positions close to the boundaries. Different rules have been suggested in the literature with justifications based on simulation studies. Herein the relevant stochastic differential equation model is formulated in a particular way. The formulation is based on the marginal transformation of the position...... velocity distributions that depend on height above the ground both with respect to standard deviation and skewness are substituted into the stationary Fokker/Planck equation. The particle position distribution is taken to be uniform *the well/mixed condition( and also a given dispersion coefficient...

  18. Atmospheric Pressure Plasma Treatment for Grey Cotton Knitted Fabric

    Directory of Open Access Journals (Sweden)

    Chi-wai Kan

    2018-01-01

    Full Text Available 100% grey cotton knitted fabric contains impurities and yellowness and needs to be prepared for processing to make it suitable for coloration and finishing. Therefore, conventionally 100% grey cotton knitted fabric undergoes a process of scouring and bleaching, which involves the use of large amounts of water and chemicals, in order to remove impurities and yellowness. Due to increased environmental awareness, pursuing a reduction of water and chemicals is a current trend in textile processing. In this study, we explore the possibility of using atmospheric pressure plasma as a dry process to treat 100% grey cotton knitted fabric (single jersey and interlock before processing. Experimental results reveal that atmospheric pressure plasma treatment can effectively remove impurities from 100% grey cotton knitted fabrics and significantly improve its water absorption property. On the other hand, if 100% grey cotton knitted fabrics are pretreated with plasma and then undergo a normal scouring process, the treatment time is reduced. In addition, the surface morphological and chemical changes in plasma-treated fabrics were studied and compared with the conventionally treated fabrics using scanning electron microscope (SEM, Fourier-transform infrared spectroscopy-attenuated total reflection (FTIR-ATR and X-ray photoelectron spectroscopy (XPS. The decrease in carbon content, as shown in XPS, reveal the removal of surface impurities. The oxygen-to-carbon (O/C ratios of the plasma treated knitted fabrics reveal enhanced hydrophilicity.

  19. Advanced Atmospheric Ensemble Modeling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Chiswell, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kurzeja, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Maze, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Viner, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Werth, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-29

    Ensemble modeling (EM), the creation of multiple atmospheric simulations for a given time period, has become an essential tool for characterizing uncertainties in model predictions. We explore two novel ensemble modeling techniques: (1) perturbation of model parameters (Adaptive Programming, AP), and (2) data assimilation (Ensemble Kalman Filter, EnKF). The current research is an extension to work from last year and examines transport on a small spatial scale (<100 km) in complex terrain, for more rigorous testing of the ensemble technique. Two different release cases were studied, a coastal release (SF6) and an inland release (Freon) which consisted of two release times. Observations of tracer concentration and meteorology are used to judge the ensemble results. In addition, adaptive grid techniques have been developed to reduce required computing resources for transport calculations. Using a 20- member ensemble, the standard approach generated downwind transport that was quantitatively good for both releases; however, the EnKF method produced additional improvement for the coastal release where the spatial and temporal differences due to interior valley heating lead to the inland movement of the plume. The AP technique showed improvements for both release cases, with more improvement shown in the inland release. This research demonstrated that transport accuracy can be improved when models are adapted to a particular location/time or when important local data is assimilated into the simulation and enhances SRNL’s capability in atmospheric transport modeling in support of its current customer base and local site missions, as well as our ability to attract new customers within the intelligence community.

  20. Innovative measurement within the atmosphere of Venus.

    Science.gov (United States)

    Ekonomov, Alexey; Linkin, Vyacheslav; Manukin, Anatoly; Makarov, Vladislav; Lipatov, Alexander

    The results of Vega project experiments with two balloons flew in the cloud layer of the atmosphere of Venus are analyzed as to the superrotation nature and local dynamic and thermodynamic characteristics of the atmosphere. These balloons in conjunction with measurements of temperature profiles defined by the Fourier spectrometer measurements from the spacecraft Venera 15 allow us to offer a mechanism accelerating the atmosphere to high zonal velocities and supporting these speeds, the atmosphere superrotation in general. Spectral measurements with balloons confirm the possibility of imaging the planet's surface from a height of not more than 55 km. Promising experiments with balloons in the atmosphere of Venus are considered. In particular, we discuss the possibility of measuring the geopotential height, as Venus no seas and oceans to vertical positioning of the temperature profiles. As an innovative research facilities within the atmosphere overpressure balloon with a lifetime longer than 14 Earth days and vertical profile microprobes are considered.

  1. Recovering of images degraded by atmosphere

    Science.gov (United States)

    Lin, Guang; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

    2017-08-01

    Remote sensing images are seriously degraded by multiple scattering and bad weather. Through the analysis of the radiative transfer procedure in atmosphere, an image atmospheric degradation model considering the influence of atmospheric absorption multiple scattering and non-uniform distribution is proposed in this paper. Based on the proposed model, a novel recovering method is presented to eliminate atmospheric degradation. Mean-shift image segmentation and block-wise deconvolution are used to reduce time cost, retaining a good result. The recovering results indicate that the proposed method can significantly remove atmospheric degradation and effectively improve contrast compared with other removal methods. The results also illustrate that our method is suitable for various degraded remote sensing, including images with large field of view (FOV), images taken in side-glance situations, image degraded by atmospheric non-uniform distribution and images with various forms of clouds.

  2. Designing Affective Atmospheres on the Move

    DEFF Research Database (Denmark)

    Wind, Simon; Lanng, Ditte Bendix

    travelling “unfolds affects as much as reasons” (Jensen, 2013, p.99). Practices, embodiment, technologies and materialities interconnect in non-quantifiable experiences of mobilities, which may fruitfully be unfolded by means of the concept of “atmosphere”. According to Böhme, atmosphere cannot be reduced...... to properties or qualities of neither human nor non-human bodies but they are “manifestations of the co-presence of subject and object” (Böhme, 1998, p.114). When travelling in and through spaces of mobilities in everyday life we are co-constituents in an on-flow of aesthetic atmospheres shaping emotional...... an analytical tool for capturing atmospheres as well as an interventionist tool for orchestrating atmospheres in everyday urban spaces of mobilities. References Anderson, B. (2009) ´Affective Atmospheres´, in: Emotion, Space and Society, pp. 77–81 Bissel, D. (2010) ´Passenger mobilities: affective atmospheres...

  3. Thermal Conductivity of the Multicomponent Neutral Atmosphere

    Science.gov (United States)

    Pavlov, A. V.

    2017-12-01

    Approximate expressions for the thermal conductivity coefficient of the multicomponent neutral atmosphere consisting of N2, O2, O, He, and H are analyzed and evaluated for the atmospheric conditions by comparing them with that given by the rigorous hydrodynamic theory. The new approximations of the thermal conductivity coefficients of simple gases N2, O2, O, He, and H are derived and used. It is proved that the modified Mason and Saxena approximation of the atmospheric thermal conductivity coefficient is more accurate in reproducing the atmospheric values of the rigorous hydrodynamic thermal conductivity coefficient in comparison with those that are generally accepted in atmospheric studies. This approximation of the thermal conductivity coefficient is recommended to use in calculations of the neutral temperature of the atmosphere.

  4. Atmospheric oxidation of selected alcohols and esters

    Energy Technology Data Exchange (ETDEWEB)

    Becker, K H; Cavalli, F

    2001-03-01

    The decision whether it is appropriate and beneficial for the environment to deploy specific oxygenated organic compounds as replacements for traditional solvent types requires a quantitative assessment of their potential atmospheric impacts including tropospheric ozone and other photooxidant formation. This involves developing chemical mechanisms for the gasphase atmospheric oxidation of the compounds which can be reliably used in models to predict their atmospheric reactivity under a variety of environmental conditions. Until this study, there was very little information available concerning the atmospheric fate of alcohols and esters. The objectives of this study were to measure the atmospheric reaction rates and to define atmospheric reaction mechanisms for the following selected oxygenated volatile organic compounds: the alcohols, 1-butanol and 1-pentanol, and the esters, methyl propionate and dimethyl succinate. The study has successfully addressed these objectives. (orig.)

  5. Atmospheric correction of APEX hyperspectral data

    Directory of Open Access Journals (Sweden)

    Sterckx Sindy

    2016-03-01

    Full Text Available Atmospheric correction plays a crucial role among the processing steps applied to remotely sensed hyperspectral data. Atmospheric correction comprises a group of procedures needed to remove atmospheric effects from observed spectra, i.e. the transformation from at-sensor radiances to at-surface radiances or reflectances. In this paper we present the different steps in the atmospheric correction process for APEX hyperspectral data as applied by the Central Data Processing Center (CDPC at the Flemish Institute for Technological Research (VITO, Mol, Belgium. The MODerate resolution atmospheric TRANsmission program (MODTRAN is used to determine the source of radiation and for applying the actual atmospheric correction. As part of the overall correction process, supporting algorithms are provided in order to derive MODTRAN configuration parameters and to account for specific effects, e.g. correction for adjacency effects, haze and shadow correction, and topographic BRDF correction. The methods and theory underlying these corrections and an example of an application are presented.

  6. New insights into the atmospheric mercury cycling in central Antarctica and implications on a continental scale

    Directory of Open Access Journals (Sweden)

    H. Angot

    2016-07-01

    Full Text Available Under the framework of the GMOS project (Global Mercury Observation System atmospheric mercury monitoring has been implemented at Concordia Station on the high-altitude Antarctic plateau (75°06′ S, 123°20′ E, 3220 m above sea level. We report here the first year-round measurements of gaseous elemental mercury (Hg(0 in the atmosphere and in snowpack interstitial air on the East Antarctic ice sheet. This unique data set shows evidence of an intense oxidation of atmospheric Hg(0 in summer (24-hour daylight due to the high oxidative capacity of the Antarctic plateau atmosphere in this period of the year. Summertime Hg(0 concentrations exhibited a pronounced daily cycle in ambient air with maximal concentrations around midday. Photochemical reactions and chemical exchange at the air–snow interface were prominent, highlighting the role of the snowpack on the atmospheric mercury cycle. Our observations reveal a 20 to 30 % decrease of atmospheric Hg(0 concentrations from May to mid-August (winter, 24 h darkness. This phenomenon has not been reported elsewhere and possibly results from the dry deposition of Hg(0 onto the snowpack. We also reveal the occurrence of multi-day to weeklong atmospheric Hg(0 depletion events in summer, not associated with depletions of ozone, and likely due to a stagnation of air masses above the plateau triggering an accumulation of oxidants within the shallow boundary layer. Our observations suggest that the inland atmospheric reservoir is depleted in Hg(0 in summer. Due to katabatic winds flowing out from the Antarctic plateau down the steep vertical drops along the coast and according to observations at coastal Antarctic stations, the striking reactivity observed on the plateau most likely influences the cycle of atmospheric mercury on a continental scale.

  7. Global Hawk dropsonde observations of the Arctic atmosphere obtained during the Winter Storms and Pacific Atmospheric Rivers (WISPAR field campaign

    Directory of Open Access Journals (Sweden)

    J. M. Intrieri

    2014-11-01

    Full Text Available In February and March of 2011, the Global Hawk unmanned aircraft system (UAS was deployed over the Pacific Ocean and the Arctic during the Winter Storms and Pacific Atmospheric Rivers (WISPAR field campaign. The WISPAR science missions were designed to (1 mprove our understanding of Pacific weather systems and the polar atmosphere; (2 evaluate operational use of unmanned aircraft for investigating these atmospheric events; and (3 demonstrate operational and research applications of a UAS dropsonde system at high latitudes. Dropsondes deployed from the Global Hawk successfully obtained high-resolution profiles of temperature, pressure, humidity, and wind information between the stratosphere and surface. The 35 m wingspan Global Hawk, which can soar for ~ 31 h at altitudes up to ~ 20 km, was remotely operated from NASA's Dryden Flight Research Center at Edwards Air Force Base (AFB in California. During the 25 h polar flight on 9–10 March 2011, the Global Hawk released 35 sondes between the North Slope of Alaska and 85° N latitude, marking the first UAS Arctic dropsonde mission of its kind. The polar flight transected an unusually cold polar vortex, notable for an associated record-level Arctic ozone loss, and documented polar boundary layer variations over a sizable ocean–ice lead feature. Comparison of dropsonde observations with atmospheric reanalyses reveal that, for this day, large-scale structures such as the polar vortex and air masses are captured by the reanalyses, while smaller-scale features, including low-level jets and inversion depths, are mischaracterized. The successful Arctic dropsonde deployment demonstrates the capability of the Global Hawk to conduct operations in harsh, remote regions. The limited comparison with other measurements and reanalyses highlights the potential value of Arctic atmospheric dropsonde observations where routine in situ measurements are practically nonexistent.

  8. Lidar investigations of atmospheric aerosols over Sofia

    International Nuclear Information System (INIS)

    Dreischuh, T.; Deleva, A.; Peshev, Z.; Grigorov, I.; Kolarov, G.; Stoyanov, D.

    2016-01-01

    An overview is given of the laser remote sensing of atmospheric aerosols and related processes over the Sofia area performed in the Institute of Electronics, Bulgarian Academy of Sciences, during the last three years. Results from lidar investigations of the optical characteristics of atmospheric aerosols obtained in the frame of the European Aerosol Research Lidar Network, as well as from the lidar mapping of near-surface aerosol fields for remote monitoring of atmospheric pollutants are presented and discussed in this paper.

  9. The atmospheric temperature structure of Titan

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, J. B.; Courtin, Regis; Lunine, Jonathan I.

    1992-01-01

    The contribution of various factors to the thermal structure of Titan's past and present atmosphere are discussed. A one dimensional model of Titan's thermal structure is summarized. The greenhouse effect of Titan's atmosphere, caused primarily by pressure induced opacity of N2, CH4, and H2, is discussed together with the antigreenhouse effect dominated by the haze which absorbs incident sunlight. The implications for the atmosphere of the presence of an ocean on Titan are also discussed.

  10. Modelling of pollution dispersion in atmosphere

    International Nuclear Information System (INIS)

    Borysiewicz, M.; Stankiewicz, R.

    1994-01-01

    The paper contains the review of the mathematical foundation of atmospheric dispersion models. The atmospheric phenomena relevant to atmospheric dispersion model are discussed. In particular the parametrization of processes with time and space scales smaller than numerical grid size, limited by available computer power, is presented. The special attention was devoted to similarity theory and parametrization of boundary layer. The numerical methods are analysed and the drawbacks of the method are presented. (author). 99 refs, 15 figs, 3 tabs

  11. WFIRST: Exoplanet Data Challenge. Atmospheric retrieval results

    Science.gov (United States)

    Hildebrandt, Sergi; Turnbull, Margaret; Exoplanet Data Challenge Team

    2018-01-01

    We present the results of the Exoplanet Data Challenge for its first 2016/17 cycle and the current cycle 2. Some input spectra for extra-solar systems are processed through the WFIRST IFS instrument model, producing simulated data representative of the flight data. Atmospheric properties are then recovered using complex atmospheric models and multidimensional optimization. The results inform about WFIRST CGI ability to characterize exo-planetray atmospheres.

  12. Atmospheric methods for nuclear test monitoring

    International Nuclear Information System (INIS)

    Simons, D.J.

    1995-01-01

    The U.S. DOE sponsored research investigating atmospheric infrasound as a means of detecting both atmospheric and underground nuclear tests. Various detection schemes were examined and were found to be effective for different situations. It has been discovered that an enhanced sensitivity is realizable for the very lowest frequency disturbances by detecting the infrasound at the top of the atmosphere using ratio sound techniques. These techniques are compared to more traditional measurement schemes

  13. Composition of atmospheric precipitation. I. Nitrogen compounds

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, E

    1952-01-01

    The purpose of this paper is to present a survey of published data on chemical analysis of atmospheric precipitation to discuss different cycles proposed for inorganic compounds in atmospheric precipitation and, finally, to assess the importance of these compounds from different points of view. Investigations of rainwater with a view to determine atmospheric pollution in industrial areas are mentioned incidentally but no results are detailed.

  14. Atmospheric Electricity and Tethered Aerostats, Volume 2

    Science.gov (United States)

    1976-05-11

    EASTERN TEST RANGE PATRICK AIR FORCE BASE, FLORIDA 11 MAY 1976 028 099 AFETR -TR-76-07 ATMOSPHERIC ELECTRICITY AND ~TETHERED AEROSTATS, VOLUME 11 Range...number) Atmospheric Electricity Lightning- Effects , Protection, Warning Balloons Systems Conducting & Nonconducting Tethers Potential Gradient Anomalies...if necessary and Identify by block number) Part A, "Atmospheric Electrical Effects of and on Tethered Balloon Systems," by Latham includes airborne

  15. Atmospheric pollution. From processes to modelling

    International Nuclear Information System (INIS)

    Sportisse, B.

    2008-01-01

    Air quality, greenhouse effect, ozone hole, chemical or nuclear accidents.. All these phenomena are tightly linked to the chemical composition of atmosphere and to the atmospheric dispersion of pollutants. This book aims at supplying the main elements of understanding of 'atmospheric pollutions': stakes, physical processes involved, role of scientific expertise in decision making. Content: 1 - classifications and scales: chemical composition of the atmosphere, vertical structure, time scales (transport, residence); 2 - matter/light interaction: notions of radiative transfer, application to the Earth's atmosphere; 3 - some elements about the atmospheric boundary layer: notion of scales in meteorology, atmospheric boundary layer (ABL), thermal stratification and stability, description of ABL turbulence, elements of atmospheric dynamics, some elements about the urban climate; 4 - notions of atmospheric chemistry: characteristics, ozone stratospheric chemistry, ozone tropospheric chemistry, brief introduction to indoor air quality; 5 - aerosols, clouds and rains: aerosols and particulates, aerosols and clouds, acid rains and leaching; 6 - towards numerical simulation: equation of reactive dispersion, numerical methods for chemistry-transport models, numerical resolution of the general equation of aerosols dynamics (GDE), modern simulation chains, perspectives. (J.S.)

  16. Denitrification, nitrification, and atmospheric nitrous oxide

    National Research Council Canada - National Science Library

    Delwiche, C. C

    1981-01-01

    In this book, a number of unanswered questions particularly demanding of attention are analyzed to determine the significance of various chemical and biological processes involved with the atmospheric...

  17. Increasing atmospheric carbon dioxide and its consequences

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, J G

    1982-09-16

    The effects of increasing CO/sub 2/ concentrations in the atmosphere are estimated using general circulation models (GCMs), which have the ability to portray many of the nonlinear feedback processes which serve to regulate atmospheric (and hence climatic) changes. GCMs predict that a doubling of atmospheric CO/sub 2/ would result in a 2-3 k increase of globally averaged surface air temperature. The largest warming will occur in the winter in high latitudes. Detection studies are now being directed towards isolating those parts of observed climate fluctuations that are attributable to increasing atmospheric CO/sub 2/. (KRM)

  18. On The Implications of Atmospheric Gravity Waves on Wind Power

    OpenAIRE

    Norris, Luke

    2011-01-01

    In view of the rapidly rising cost of fossil fuels and concerns over climate change, there can be little doubt that renewable energy is to play a large role in the future of our economic development. The impact of Atmospheric Gravity Waves (AGWs) on wind power is, at best, unclear. In this research, AGWs are successfully modelled both in theoretical and real world environments using the WindSim software package which has revealed a potential 7.4% drop in annual power output as a direct ...

  19. Study of a dual frequency atmospheric pressure corona plasma

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Moon, S. Y.; Jung, H.; Gweon, B.; Choe, Wonho

    2010-01-01

    Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressure corona plasma. As a result of the dual frequency, length, current density, and electron excitation temperature of the plasma were increased, while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover, observation of time-resolved images revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer, 2 MHz negative glow, and 13.56 MHz continuous glow.

  20. Stochastic excitation of low frequency variability in the midlatitude atmosphere

    International Nuclear Information System (INIS)

    Ioannou, P.J.; Farrell, B.F.

    1994-01-01

    Spectral analysis of the transient geopotential variance of the midlatitude atmosphere reveals a sharp peak in the wavenumber-period spectra concentrated at large scales (zonal wave numbers m 10 days). This is surprising because conventional baroclinic instability calculations predict a broad maximum of the variance at synoptic scale (8 < m < 12) with associated period of a few days. In this work we review the method for calculating the maintained variance and associated fluxes and then discuss some results pertaining to the interpretation of the EOF's which arise from the stochastic dynamics of non-normal dynamical systems

  1. Some aspects of composition of the lower Martian atmosphere: input for MIRA

    Science.gov (United States)

    Moroz, V.; Korablev, O.; Krasnopolsky, V.; Rorin, A.

    Recent spacecraft missions and high-resolution spectroscopic observations from the Earth-based, airborne and spaceborne observatories have justified the chemical contents of the Martian atmosphere at a new level of confidence. Both the lower and middle atmosphere of Mars reveal very limited chemical activity, while the variations of the abundance of minor constituents may be attributed to phase transitions of volatiles. Water vapor, which mixing ratio is controlled by complex hydrological cycle in the lower atmosphere and at the surface of the planet, affects seasonally varying depletion of ozone. Measured ratio of D/H can be explained with general models of the early evolution of the planet, though this estimate in the bulk atmosphere may not be ultimately representative due to altitude dependant fractionation of water isotopes. CO, as a chemically passive nonvolatile component, reveals increase of mixing ratio in the vicinity of winter polar caps during active condensation of the bulk CO2 atmosphere. No reliable evidence o any organicf matter in the atmosphere of Mars has been obtained.

  2. Archiving Derived Data with the PDS Atmospheres Node: The Educational Labeling System for Atmospheres (ELSA)

    Science.gov (United States)

    Neakrase, L. D. V.; Hornung, D.; Chanover, N.; Huber, L.; Beebe, R.; Johnson, J.; Sweebe, K.; Stevenson, Z.

    2017-06-01

    The PDS Atmospheres Node is developing an online tool, the Educational Labeling System for Atmospheres (ELSA), to aid in planning and creation of PDS4 bundles and associated labels for archiving derived data.

  3. Swell impact on wind stress and atmospheric mixing in a regional coupled atmosphere-wave model

    DEFF Research Database (Denmark)

    Wu, Lichuan; Rutgersson, Anna; Sahlée, Erik

    2016-01-01

    Over the ocean, the atmospheric turbulence can be significantly affected by swell waves. Change in the atmospheric turbulence affects the wind stress and atmospheric mixing over swell waves. In this study, the influence of swell on atmospheric mixing and wind stress is introduced into an atmosphere-wave-coupled...... regional climate model, separately and combined. The swell influence on atmospheric mixing is introduced into the atmospheric mixing length formula by adding a swell-induced contribution to the mixing. The swell influence on the wind stress under wind-following swell, moderate-range wind, and near......-neutral and unstable stratification conditions is introduced by changing the roughness length. Five year simulation results indicate that adding the swell influence on atmospheric mixing has limited influence, only slightly increasing the near-surface wind speed; in contrast, adding the swell influence on wind stress...

  4. Atmospheric fluoride pollution. Part II

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T; Yamazaki, Y

    1969-01-01

    In East Osaka, agricultural crops either died or showed poor growth in the neighborhood of a factory producing white cosmetic bottles. Since fluorite was used as a material and there was no damage before the establishment of the factory, it was suspected that fluorine compounds were causing the damage. Quantitative analysis was performed on the agricultural crops and the exhaust gas as well as the dust particles in order to determine the fluorine content. Gas samplers were used to collect the dusts from the surrounding atmosphere. The fluorine content of dust near the factory was about 93 mg per cubic meter per day, and in some parts, as high as 1.54 mq per cubic meter per day. Relatively larger quantities of fluorine were measured at the southwestern and southeastern area of the factory, corresponding to the general wind pattern. Rice and soy beans from the neighborhood of the factory showed concentrations of fluorine and, especially in the leaves of the damaged crops, the concentrations were several hundred times higher than those of the undamaged leaves.

  5. Mortality, fog and atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A E; Bradley, W H

    1960-01-01

    A study was made associating climate and atmospheric pollution with excess mortality in greater London during the winter of 1958 and 1959. It was a particularly foggy winter with 6 major episodes, 4 of which resembled previous dangerous smogs. There were two additional periods of high pollution without fog. Excess mortality during these 8 periods ranged from 70 to 230. During one period, a flu epidemic accompanied the fog. In 4 to 6 foggy periods, morbidity (hospital bed demand) also increased. This small number of observations indicates mortality association: on 2/3 of days with high SO/sub 2/ (2.5 pphM) or high particulate soot (10 mg/m/sup 3/), and on all days with thick fog, there was an increase in mortality (20 deaths more than previous day) on that or the following day. Fifteen-day moving mortality index and bronchitis mortality index were significantly correlated with black suspended matter and SO/sub 2/; association with pneumonia was not significant. Also little or no relation between mortality and humidity, mean temperature, or barometric pressure was found. Rapid response of mortality to air pollution may indicate that pollution affects mostly those already ill.

  6. Report from upper atmospheric science

    International Nuclear Information System (INIS)

    Carignan, G.R.; Roble, R.G.; Mende, S.B.; Nagy, A.F.; Hudson, R.D.

    1989-01-01

    Most of the understanding of the thermosphere resulted from the analysis of data accrued through the Atmosphere Explorer satellites, the Dynamics Explorer 2 satellite, and observations from rockets, balloons, and ground based instruments. However, new questions were posed by the data that have not yet been answered. The mesosphere and lower thermosphere have been less thoroughly studied because of the difficulty of accessibility on a global scale, and many rather fundamental characteristics of these regions are not well understood. A wide variety of measurement platforms can be used to implement various parts of a measurement strategy, but the major thrusts of the International Solar Terrestrial Physics Program would require Explorer-class missions. A remote sensing mission to explore the mesosphere and lower thermosphere and one and two Explorer-type spacecraft to enable a mission into the thermosphere itself would provide the essential components of a productive program of exploration of this important region of the upper atomsphere. Theoretical mission options are explored

  7. Middle atmosphere electrical energy coupling

    Science.gov (United States)

    Hale, L. C.

    1989-01-01

    The middle atmosphere (MA) has long been known as an absorber of radio waves, and as a region of nonlinear interactions among waves. The region of highest transverse conductivity near the top of the MA provides a common return for global thunderstorm, auroral Birkeland, and ionospheric dynamo currents, with possibilities for coupling among them. Their associated fields and other transverse fields map to lower altitudes depending on scale size. Evidence now exists for motion-driven aerosol generators, and for charge trapped at the base of magnetic field lines, both capable of producing large MA electric fields. Ionospheric Maxwell currents (curl H) parallel to the magnetic field appear to map to lower altitudes, with rapidly time-varying components appearing as displacement currents in the stratosphere. Lightning couples a (primarily ELF and ULF) current transient to the ionosphere and magnetosphere whose wave shape is largely dependent on the MA conductivity profile. Electrical energy is of direct significance mainly in the upper MA, but electrodynamic transport of minor constituents such as smoke particles or CN may be important at other altitudes.

  8. Atmospheric mercury footprints of nations.

    Science.gov (United States)

    Liang, Sai; Wang, Yafei; Cinnirella, Sergio; Pirrone, Nicola

    2015-03-17

    The Minamata Convention was established to protect humans and the natural environment from the adverse effects of mercury emissions. A cogent assessment of mercury emissions is required to help implement the Minamata Convention. Here, we use an environmentally extended multi-regional input-output model to calculate atmospheric mercury footprints of nations based on upstream production (meaning direct emissions from the production activities of a nation), downstream production (meaning both direct and indirect emissions caused by the production activities of a nation), and consumption (meaning both direct and indirect emissions caused by final consumption of goods and services in a nation). Results show that nations function differently within global supply chains. Developed nations usually have larger consumption-based emissions than up- and downstream production-based emissions. India, South Korea, and Taiwan have larger downstream production-based emissions than their upstream production- and consumption-based emissions. Developed nations (e.g., United States, Japan, and Germany) are in part responsible for mercury emissions of developing nations (e.g., China, India, and Indonesia). Our findings indicate that global mercury abatement should focus on multiple stages of global supply chains. We propose three initiatives for global mercury abatement, comprising the establishment of mercury control technologies of upstream producers, productivity improvement of downstream producers, and behavior optimization of final consumers.

  9. Improving practical atmospheric dispersion models

    International Nuclear Information System (INIS)

    Hunt, J.C.R.; Hudson, B.; Thomson, D.J.

    1992-01-01

    The new generation of practical atmospheric dispersion model (for short range ≤ 30 km) are based on dispersion science and boundary layer meteorology which have widespread international acceptance. In addition, recent improvements in computer skills and the widespread availability of small powerful computers make it possible to have new regulatory models which are more complex than the previous generation which were based on charts and simple formulae. This paper describes the basis of these models and how they have developed. Such models are needed to satisfy the urgent public demand for sound, justifiable and consistent environmental decisions. For example, it is preferable that the same models are used to simulate dispersion in different industries; in many countries at present different models are used for emissions from nuclear and fossil fuel power stations. The models should not be so simple as to be suspect but neither should they be too complex for widespread use; for example, at public inquiries in Germany, where simple models are mandatory, it is becoming usual to cite the results from highly complex computational models because the simple models are not credible. This paper is written in a schematic style with an emphasis on tables and diagrams. (au) (22 refs.)

  10. Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution

    OpenAIRE

    Skarżyńska, K.; Polkowska, Ż; Namieśnik, J.

    2006-01-01

    This paper reviews techniques and equipment for collecting precipitation samples from the atmosphere (fog and cloud water) and from atmospheric deposits (dew, hoarfrost, and rime) that are suitable for the evaluation of atmospheric pollution. It discusses the storage and preparation of samples for analysis and also presents bibliographic information on the concentration ranges of inorganic and organic compounds in the precipitation and atmospheric deposit samples.

  11. Transparency masters for mathematics revealed

    CERN Document Server

    Berman, Elizabeth

    1980-01-01

    Transparency Masters for Mathematics Revealed focuses on master diagrams that can be used for transparencies for an overhead projector or duplicator masters for worksheets. The book offers information on a compilation of master diagrams prepared by John R. Stafford, Jr., audiovisual supervisor at the University of Missouri at Kansas City. Some of the transparencies are designed to be shown horizontally. The initial three masters are number lines and grids that can be used in a mathematics course, while the others are adaptations of text figures which are slightly altered in some instances. The

  12. Annual atmospheric mercury species in downtown Toronto, Canada.

    Science.gov (United States)

    Song, Xinjie; Cheng, Irene; Lu, Julia

    2009-03-01

    Real-time concentrations of atmospheric gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and mercury associated with particles having sizes RGM were 4.5 +/- 3.1 ng m(-3) (99.2%), 21.5 +/- 16.4 pg m(-3) (0.5%) and 14.2 +/- 13.2 pg m(-3) (0.3%), respectively. The concentrations for all the measured Hg species were highly variable throughout the year and were lower in winter than in the other three seasons. The maximum concentrations of Hg species were observed in June and were a result of the high number of Hg spikes (using [GEM] >10 ng m(-3) as an indicator) that occurred in the month. Nighttime (between 9pm-6am) concentrations of Hg species were higher than those of daytime. The results revealed: (1) an urban area is a continuous source of Hg species that have the potential to pose impacts on local, regional and global scales; (2) local/regional anthropogenic sources contributed significantly to the levels and the distributions of the Hg species in the urban atmosphere. More studies are needed to identify and quantify the anthropogenic sources of Hg and the Hg species emitted from these sources; (3) surface emission and photochemical reactions (including the reactions involving ozone) did not have significant influence on the levels of Hg species and their distribution in the urban atmosphere.

  13. Chernobyl source term, atmospheric dispersion, and dose estimation

    International Nuclear Information System (INIS)

    Gudiksen, P.H.; Harvey, T.F.; Lange, R.

    1988-02-01

    The Chernobyl source term available for long-range transport was estimated by integration of radiological measurements with atmospheric dispersion modeling, and by reactor core radionuclide inventory estimation in conjunction with WASH-1400 release fractions associated with specific chemical groups. These analyses indicated that essentially all of the noble gases, 80% of the radioiodines, 40% of the radiocesium, 10% of the tellurium, and about 1% or less of the more refractory elements were released. Atmospheric dispersion modeling of the radioactive cloud over the Northern Hemisphere revealed that the cloud became segmented during the first day, with the lower section heading toward Scandinavia and the uppper part heading in a southeasterly direction with subsequent transport across Asia to Japan, the North Pacific, and the west coast of North America. The inhalation doses due to direct cloud exposure were estimated to exceed 10 mGy near the Chernobyl area, to range between 0.1 and 0.001 mGy within most of Europe, and to be generally less than 0.00001 mGy within the US. The Chernobyl source term was several orders of magnitude greater than those associated with the Windscale and TMI reactor accidents, while the 137 Cs from the Chernobyl event is about 6% of that released by the US and USSR atmospheric nuclear weapon tests. 9 refs., 3 figs., 6 tabs

  14. Waterspout as a special type of atmospheric aerosol dusty plasma

    Science.gov (United States)

    Rantsev-Kartinov, Valentin A.

    2004-11-01

    An analysis of databases of photographic images of oceanic surface revealed the presence of oceanic skeletal structures (OSS) [1] Rantsev-Kartinov V.A., Preprint . The OSSs presumably differ from the formerly found skeletal structures (SS) (Phys. Lett. A 306 (2002) 175) only by the fact that OSS are filled in with the closely packed blocks of a smaller size, up to thin, tens of microns-sized capillaries. The SSs in the Earth atmosphere were suggested [1] to be produced during atmospheric electricity activity by the volcanic-born dust. The fall-out of such SSs on the oceanic surface is a material source of OSS. Here we suggest that an OSS block [1] in the form of vertically oriented floating cylinder may be a stimulator of waterspout (WS). The main body of WS may be interpreted as a special type of atmospheric aerosol dusty plasma, and WS column - as a long-lived filament, being formed in the process of electric breakdown between the cloud and oceanic surface. The charged water drops aerosol may behave similar to microdust and lift upward to the cloud by the electrostatic force. With such a capillary&;electrostatic model of WS, it appears possible to interpret many effects related to WS.

  15. Dynamical variability in Saturn Equatorial Atmosphere

    Science.gov (United States)

    Sánchez-Lavega, A.; Pérez-Hoyos, S.; Hueso, R.; Rojas, J. F.; French, R. G.; Grupo Ciencias Planetarias Team

    2003-05-01

    Historical ground-based and recent HST observations show that Saturn's Equatorial Atmosphere is the region where the most intense large-scale dynamical variability took place at cloud level in the planet. Large-scale convective storms (nicknamed the ``Great White Spots") occurred in 1876, 1933 and 1990. The best studied case (the 1990 storm), produced a dramatic change in the cloud aspect in the years following the outburst of September 1990. Subsequently, a new large storm formed in 1994 and from 1996 to 2002 our HST observations showed periods of unusual cloud activity in the southern part of the Equator. This contrast with the aspect observed during the Voyager 1 and 2 encounters in 1980 and 1981 when the Equator was calm, except for some mid-scale plume-like features seen in 1981. Cloud-tracking of the features have revealed a dramatic slow down in the equatorial winds from maximum velocities of ˜ 475 m/s in 1980-1981 to ˜ 275 m/s during 1996-2002, as we have recently reported in Nature, Vol. 423, 623 (2003). We discuss the possibility that seasonal and ring-shadowing effects are involved in generating this activity and variability. Acknowledgements: This work was supported by the Spanish MCYT PNAYA 2000-0932. SPH acknowledges a PhD fellowship from the Spanish MECD and RH a post-doc fellowship from Gobierno Vasco. RGF was supported in part by NASA's Planetary Geology and Geophysics Program NAG5-10197 and STSCI Grant GO-08660.01A.

  16. Shock Synthesis in the Atmosphere of Jupiter

    Science.gov (United States)

    Khare, B. N.; Sagan, C.; McDonald, G. D.; de Vanssay, E.; Borucki, W. J.; McKay, C. P.; Bernstein, M. P.; Hartman, T. G.; Lech, J.

    1996-09-01

    We have previously investigated an approximate simulation of the Jupiter troposphere at the 1 bar NH_3 cloud level using Laser Induced Plasma (LIP) for shock synthesis in a 84.62:13.3:1.07:1.01 H_2:He:CH_4:NH_3 gas mixture, and found by GC/MS that HCN is the most abundant product, more abundant than all the major product hydrocarbons (C_2H_6, C_2H_2, C_3H_8, and C_4H10) combined. Using purge and trap isolation techniques on the LIP gas mixture using two absorbent traps in tandem, thermal desorption GC/MS has revealed a large array of product molecules starting from simple hydrocarbons such as C_2H_2, C_2H_4, etc., simple nitriles such as HCN, CH_3CN, etc., to molecules up to C13 (e.g. C13H23N). Here we report the results of our more accurate simulation of Jupiter at the 5 bar level using LIP with a 88:11.7:0.2:0.1 H_2:He:CH_4:NH_3 mixture, for comparison with mass spectral data from the Galileo probe. We detect in this more acurate simulation of Jupiter many of the same compounds, such as HCN, dimethylaminoacetonitrile, and dimethylcyanamide, as in the previous lower dilution experiment. We will compare the present results with those from low-pressure continuous flow plasma discharge experiments (McDonald et al. 1992, al Icarus 99, 131). We will also discuss the relevance of our data in light of the significant discrepancies between standard models of the jovian atmosphere and the compositional data returned by the Galileo entry probe.

  17. Atmospheric phenomena deduced from radiosonde and GPS ...

    Indian Academy of Sciences (India)

    The tropopause height and tropopause temperature are sensitive to temperature changes in troposphere and stratosphere. These are the measures of global climatic variability. Atmospheric profiles of temperature, refractivity and water vapour are always needed for communication, navigation and atmospheric modeling ...

  18. An Atmospheric Pressure Ping-Pong "Ballometer"

    Science.gov (United States)

    Kazachkov, Alexander; Kryuchkov, Dmitriy; Willis, Courtney; Moore, John C.

    2006-01-01

    Classroom experiments on atmospheric pressure focus largely on demonstrating its existence, often in a most impressive way. A series of amusing physics demonstrations is widely known and practiced by educators teaching the topic. However, measuring the value of atmospheric pressure(P[subscript atm]) is generally done in a rather mundane way,…

  19. Atmospheric emissions from power plant cooling towers

    International Nuclear Information System (INIS)

    Micheletti, W.

    2006-01-01

    Power plant recirculated cooling systems (cooling towers) are not typically thought of as potential sources of air pollution. However, atmospheric emissions can be important considerations that may influence cooling tower design and operation. This paper discusses relevant U.S. environmental regulations for potential atmospheric pollutants from power plant cooling towers, and various methods for estimating and controlling these emissions. (orig.)

  20. Atmospheric krypton-85 during 1962 and 1963

    Energy Technology Data Exchange (ETDEWEB)

    Ehhalt, D.; Muennich, K. O.; Roether, W.; Schoelch, J.; Stich, W.

    1963-11-15

    The krypton-85 found in the atmosphere presumably originates from two different sources, namely fission bomb tests and processing of burned-out fuel elements from nuclear reactors. This paper discusses the impact of the sources of krypton in the atmosphere in greater detail.

  1. Performance engineering in the community atmosphere model

    International Nuclear Information System (INIS)

    Worley, P; Mirin, A; Drake, J; Sawyer, W

    2006-01-01

    The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years

  2. Modeling of atmospheric dispersion of radionuclides

    International Nuclear Information System (INIS)

    Baklouti, Nada

    2010-01-01

    This work is a prediction of atmospheric dispersion of radionuclide from a chronic rejection of the nuclear power generating plant that can be located in one of the Tunisian sites: Skhira or Bizerte. Also it contains a study of acute rejection 'Chernobyl accident' which was the reference for the validation of GENII the code of modeling of atmospheric dispersion.

  3. The sources of atmospheric gravity waves

    International Nuclear Information System (INIS)

    Nagpal, O.P.

    1979-01-01

    The gravity wave theory has been very successful in the interpretation of various upper atmospheric phenomena. This article offers a review of the present state of knowledge about the various sources of atmospheric gravity waves, particularly those which give rise to different types of travelling ionospheric disturbance. Some specific case studies are discussed. (author)

  4. Peranan Store Atmosphere Dalam Meningkatkan Keputusan Pembelian

    Directory of Open Access Journals (Sweden)

    Rennyta Yusiana

    2017-04-01

    ABSTRACT Bandung is a destination for domestic and foreign tourists with culinary goals. There are many restaurants and cafes offering a variety of culinary tastes, ranging from culinary archipelago to abroad. Nowadays consumers are attracted to the restaurant and cafe with a different atmosphere. One of them is the Hummingbird Eatery which implementing store homey atmosphere, with the cozy interior and dominated by furniture made of wood. Atmosphere is an important factor for consumers in choosing where to dine and relax. Cozy atmosphere with unique decor and creative appeal to a restaurant that makes consumers visit. This study aims to determine consumer response regarding the role of Store Atmosphere in increasing consumer purchasing decisions. This type of research is descriptive and quantitative, using 100 samples. Data collection techniques used were questionnaires, observations, interviews, and literature studies. This study uses SPSS V.22 and simple linear regression. The results of this study indicate that the general interior becomes a major consideration as a benefit for consumers in making purchasing decisions apart from other sub variables store atmosphere. Managers can prioritize managing general interior more effectively, because consumers prefer it in the store atmosphere. Keywords: Store Atmosphere, Purchase Decision

  5. Space Science in Action: Earth's Atmosphere [Videotape].

    Science.gov (United States)

    1999

    In this videotape recording, students learn about the layers of the atmosphere and why each is important to the survival of life on the planet. Students discover why the atmosphere is responsible for weather and see how special aircraft actually fly into hurricanes. Students build their own working barometer in a hands-on activity. Contents…

  6. Atmosphere, Science (Experimental): 5343.08.

    Science.gov (United States)

    Reese, Sandra Kay

    This unit of instruction deals with a study of the general atmosphere by layers with an emphasis on physical characteristics. The formation of layers in the atmosphere and the energy relationships that exist between them are also discussed. No requisites for prior course work, experience, or courses to be taken concurrently are required for…

  7. Atmospheric Science: It's More than Meteorology.

    Science.gov (United States)

    Smith, David R.; Krockover, Gerald H.

    1988-01-01

    Indicates that atmospheric science is not just forcasting the weather. Gives an overview of current topics in meteorology including ozone depletion, acid precipitation, winter cyclones, severe local storms, the greenhouse effect, wind shear and microbursts. Outlines the Atmospheric Sciences Education Program at Purdue University to produce…

  8. Atmospheric nitrogen compounds: Occurrence, composition and deposition

    DEFF Research Database (Denmark)

    Nielsen, T.; Pilegaard, K.; Egeløv, A.H.

    1996-01-01

    Traffic in cities and on highways is an important contributor to NOy atmospheric pollution in open areas. In this situation both the concentration and composition of NOy compounds show a wide variation and are dependent on meteorological and atmospheric chemical conditions. The proportion of NOz ...

  9. Theories for convection in stellar atmospheres

    International Nuclear Information System (INIS)

    Nordlund, Aa.

    1976-02-01

    A discussion of the fundamental differences between laboratory convection in a stellar atmosphere is presented. The shortcomings of laterally homogeneous model atmospheres are analysed, and the extent to which these shortcoming are avoided in the two-component representation is discussed. Finally a qualitative discussion on the scaling properties of stellar granulation is presented. (Auth.)

  10. Coherence degree of the fundamental Bessel-Gaussian beam in turbulent atmosphere

    Science.gov (United States)

    Lukin, Igor P.

    2017-11-01

    In this article the coherence of a fundamental Bessel-Gaussian optical beam in turbulent atmosphere is analyzed. The problem analysis is based on the solution of the equation for the transverse second-order mutual coherence function of a fundamental Bessel-Gaussian optical beam of optical radiation. The behavior of a coherence degree of a fundamental Bessel-Gaussian optical beam depending on parameters of an optical beam and characteristics of turbulent atmosphere is examined. It was revealed that at low levels of fluctuations in turbulent atmosphere the coherence degree of a fundamental Bessel-Gaussian optical beam has the characteristic oscillating appearance. At high levels of fluctuations in turbulent atmosphere the coherence degree of a fundamental Bessel-Gaussian optical beam is described by an one-scale decreasing curve which in process of increase of level of fluctuations on a line of formation of a laser beam becomes closer to the same characteristic of a spherical optical wave.

  11. A Synergistic Approach to Interpreting Planetary Atmospheres

    Science.gov (United States)

    Batalha, Natasha E.

    We will soon have the technological capability to measure the atmospheric composition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In contrast to jovian-like atmospheres, whose bulk compositions consist of hydrogen and helium, terrestrial planet atmospheres are likely comprised of high mean molecular weight secondary atmospheres, which have gone through a high degree of evolution. For example, present-day Mars has a frozen surface with a thin tenuous atmosphere, but 4 billion years ago it may have been warmed by a thick greenhouse atmosphere. Several processes contribute to a planet's atmospheric evolution: stellar evolution, geological processes, atmospheric escape, biology, etc. Each of these individual processes affects the planetary system as a whole and therefore they all must be considered in the modeling of terrestrial planets. In order to demonstrate the intricacies in modeling terrestrial planets, I use early Mars as a case study. I leverage a combination of one-dimensional climate, photochemical and energy balance models in order to create one self-consistent model that closely matches currently available climate data. One-dimensional models can address several processes: the influence of greenhouse gases on heating, the effect of the planet's geological processes (i.e. volcanoes and the carbonatesilicate cycle) on the atmosphere, the effect of rainfall on atmospheric composition and the stellar irradiance. After demonstrating the number of assumptions required to build a model, I look towards what exactly we can learn from remote observations of temperate Earths and Super Earths. However, unlike in-situ observations from our own solar system, remote sensing techniques need to be developed and understood in order to accurately characterize exo-atmospheres. I describe the models used to create synthetic transit transmission observations, which includes models of

  12. Void growth suppression by dislocation impurity atmospheres

    International Nuclear Information System (INIS)

    Weertman, J.; Green, W.V.

    1976-01-01

    A detailed calculation is given of the effect of an impurity atmosphere on void growth under irradiation damage conditions. Norris has proposed that such an atmosphere can suppress void growth. The hydrostatic stress field of a dislocation that is surrounded by an impurity atmosphere was found and used to calculate the change in the effective radius of a dislocation line as a sink for interstitials and vacancies. The calculation of the impurity concentration in a Cottrell cloud takes into account the change in hydrostatic pressure produced by the presence of the cloud itself. It is found that void growth is eliminated whenever dislocations are surrounded by a condensed atmosphere of either oversized substitutional impurity atoms or interstitial impurity atoms. A condensed atmosphere will form whenever the average impurity concentration is larger than a critical concentration

  13. Peer-Mentoring Program and Academic Atmosphere

    Directory of Open Access Journals (Sweden)

    Sri Endah Kusmartini

    2014-03-01

    Full Text Available Management of Sriwijaya State Polytechnic believes that peer-mentoring program has positive effects on students’ academic success. Moreover, it is also believed that good academic atmosphere should be developed. In line with these, researchers tried to investigate whether peer-mentoring program and academic atmosphere correlated significantly to students’ writing achievement partially and simultaneously. The research was conducted in English Department, Sriwijaya State Polytechnic with 60 samples taken randomly. Measures of Peer-mentoring Program and Academic Atmosphere were used sequentially to measure peer-mentoring program and academic atmosphere as perceived by the students. Meanwhile, writing score was used to find out writing achievement of the students. The hypotheses were tested by using Pearson Product Moment Correlation and Multiple Linear Regression. The results showed that peer-mentoring program and academic atmosphere as perceived by the students correlated significantly towards students’ writing achievement partially and simultaneously. Therefore it is recommended to continue the programs.

  14. INERT Atmosphere confinement operability test procedure

    International Nuclear Information System (INIS)

    RISENMAY, H.R.

    1999-01-01

    This Operability Test Procedure (OTP) provides instructions for testing operability of the Inert Atmosphere Confinement (IAC). The Inert Atmosphere Confinement was designed and built for opening cans of metal items that might have hydrided surfaces. Unreviewed Safety Question (USQ) PFP-97-005 addresses the discovery of suspected plutonium hydride forming on plutonium metal currently stored in the Plutonium Finishing Plant vaults. Plutonium hydride reacts quickly with air, liberating energy. The Inert Atmosphere Confinement was designed to prevent this sudden liberation of energy by opening the material in an inert argon atmosphere instead of the normal glovebox atmosphere. The IAC is located in glovebox HC-21A, room 230B of the 234-5Z Building at the Plutonium Finishing Plant (PFP) in the 200-West Area of the Hanford Site

  15. Deviations from LTE in a stellar atmosphere

    International Nuclear Information System (INIS)

    Kalkofen, W.; Klein, R.I.; Stein, R.F.

    1979-01-01

    Deviations from LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient b is smaller than unity when the radiative cross section αsub(ν) grows with frequency ν faster than ν 2 ; b exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of αsub(ν). Overpopulation (b > 1) always implies that the kinetic temperature in the statistical equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature. (author)

  16. Deviations from LTE in a stellar atmosphere

    Science.gov (United States)

    Kalkofen, W.; Klein, R. I.; Stein, R. F.

    1979-01-01

    Deviations for LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient is smaller than unity when the radiative cross section grows with frequency faster than with the square of frequency; it exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of the radiative cross section. Overpopulation always implies that the kinetic temperature in the statistical-equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature.

  17. A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

    International Nuclear Information System (INIS)

    Hörst, S. M.; Brown, M. E.

    2013-01-01

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

  18. The FLUKA atmospheric neutrino flux calculation

    CERN Document Server

    Battistoni, G.; Montaruli, T.; Sala, P.R.

    2003-01-01

    The 3-dimensional (3-D) calculation of the atmospheric neutrino flux by means of the FLUKA Monte Carlo model is here described in all details, starting from the latest data on primary cosmic ray spectra. The importance of a 3-D calculation and of its consequences have been already debated in a previous paper. Here instead the focus is on the absolute flux. We stress the relevant aspects of the hadronic interaction model of FLUKA in the atmospheric neutrino flux calculation. This model is constructed and maintained so to provide a high degree of accuracy in the description of particle production. The accuracy achieved in the comparison with data from accelerators and cross checked with data on particle production in atmosphere certifies the reliability of shower calculation in atmosphere. The results presented here can be already used for analysis by current experiments on atmospheric neutrinos. However they represent an intermediate step towards a final release, since this calculation does not yet include the...

  19. Atmospheric Infrasound during a Large Wildfire

    Science.gov (United States)

    Vance, Alexis; Elbing, Brian

    2017-11-01

    Numerous natural and manmade sources generate infrasound, including tornado producing storms, human heart, hurricanes, and volcanoes. Infrasound is currently being studied as part of Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics (CLOUD MAP), which is a multi-university collaboration focused on development and implementation of unmanned aircraft systems (UAS) and integration with sensors for atmospheric measurements. To support this effort a fixed infrasonic microphone located in Stillwater, Oklahoma has been monitoring atmospheric emissions since September of 2016. While severe storm systems is the primary focus of this work, the system also captures a wide range of infrasonic sources from distances in excess of 300 miles due to an acoustic ceiling and weak atmospheric absorption. The current presentation will focus on atmospheric infrasound observations during a large wildfire on the Kansas-Oklahoma border that occurred between March 6-22, 2017. This work was supported by NSF Grant 1539070.

  20. Atmospheric-pressure plasma activation and surface characterization on polyethylene membrane separator

    Science.gov (United States)

    Tseng, Yu-Chien; Li, Hsiao-Ling; Huang, Chun

    2017-01-01

    The surface hydrophilic activation of a polyethylene membrane separator was achieved using an atmospheric-pressure plasma jet. The surface of the atmospheric-pressure-plasma-treated membrane separator was found to be highly hydrophilic realized by adjusting the plasma power input. The variations in membrane separator chemical structure were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Chemical analysis showed newly formed carbonyl-containing groups and high surface concentrations of oxygen-containing species on the atmospheric-pressure-plasma-treated polymeric separator surface. It also showed that surface hydrophilicity primarily increased from the polar component after atmospheric-pressure plasma treatment. The surface and pore structures of the polyethylene membrane separator were examined by scanning electron microscopy, revealing a slight alteration in the pore structure. As a result of the incorporation of polar functionalities by atmospheric-pressure plasma activation, the electrolyte uptake and electrochemical impedance of the atmospheric-pressure-plasma-treated membrane separator improved. The investigational results show that the separator surface can be controlled by atmospheric-pressure plasma surface treatment to tailor the hydrophilicity and enhance the electrochemical performance of lithium ion batteries.