WorldWideScience

Sample records for atmospheres thin atmospheres

  1. Levitating atmospheres of Eddington-luminosity neutron stars I. Optically thin Thomson-scattering atmospheres

    CERN Document Server

    Wielgus, M; Sądowski, A; Narayan, R; Abramowicz, M

    2015-01-01

    In general relativity static gaseous atmospheres may be in hydrostatic balance in the absence of a supporting stellar surface, provided that the luminosity is close to the Eddington value. We construct analytic models of optically thin, spherically symmetric shells supported by the radiation pressure of a luminous central body in the Schwarzschild metric.

  2. Light self-focusing in the atmosphere: thin window model

    Science.gov (United States)

    Vaseva, Irina A.; Fedoruk, Mikhail P.; Rubenchik, Alexander M.; Turitsyn, Sergei K.

    2016-08-01

    Ultra-high power (exceeding the self-focusing threshold by more than three orders of magnitude) light beams from ground-based laser systems may find applications in space-debris cleaning. The propagation of such powerful laser beams through the atmosphere reveals many novel interesting features compared to traditional light self-focusing. It is demonstrated here that for the relevant laser parameters, when the thickness of the atmosphere is much shorter than the focusing length (that is, of the orbit scale), the beam transit through the atmosphere in lowest order produces phase distortion only. This means that by using adaptive optics it may be possible to eliminate the impact of self-focusing in the atmosphere on the laser beam. The area of applicability of the proposed “thin window” model is broader than the specific physical problem considered here. For instance, it might find applications in femtosecond laser material processing.

  3. Light self-focusing in the atmosphere: thin window model.

    Science.gov (United States)

    Vaseva, Irina A; Fedoruk, Mikhail P; Rubenchik, Alexander M; Turitsyn, Sergei K

    2016-01-01

    Ultra-high power (exceeding the self-focusing threshold by more than three orders of magnitude) light beams from ground-based laser systems may find applications in space-debris cleaning. The propagation of such powerful laser beams through the atmosphere reveals many novel interesting features compared to traditional light self-focusing. It is demonstrated here that for the relevant laser parameters, when the thickness of the atmosphere is much shorter than the focusing length (that is, of the orbit scale), the beam transit through the atmosphere in lowest order produces phase distortion only. This means that by using adaptive optics it may be possible to eliminate the impact of self-focusing in the atmosphere on the laser beam. The area of applicability of the proposed "thin window" model is broader than the specific physical problem considered here. For instance, it might find applications in femtosecond laser material processing. PMID:27480220

  4. Atmospheric corrosion evaluation of galvanised steel by thin layer activation

    International Nuclear Information System (INIS)

    The release of certain metals, such as zinc, from outdoor constructions due to atmospheric corrosion is of some concern. For risk assessments the evaluation of the amount of released metal is of importance. Various methods can be used to study the release of metals. These include those using radiotracers, such as thin layer activation (TLA). To verify the reliability of TLA with respect to conventional techniques in the evaluation of atmospheric corrosion, galvanised steel was exposed to a mild marine environment. The amount of zinc in the corrosion products, released through artificial leaching, at different time intervals was evaluated by TLA and atomic absorption spectroscopy (AAS). A good correlation between the results was found indicating the feasibility of TLA for these release studies

  5. Thin film deposition on powder surfaces using atmospheric pressure discharge

    International Nuclear Information System (INIS)

    The deposition of SiOx containing films on NaCl and KBr particles in dielectric barrier discharge under atmospheric pressure was investigated. As precursor hexamethyldisiloxane (HMDSO) and tetraethoxysilane (TEOS) in argon-oxygen gas mixtures were used. The deposited layers were studied by means of light microscopy, SEM and XPS investigations. The particles could be completely covered by SiOx. With increasing oxygen content in the coating the carbon content decreases

  6. Atmospheric contamination

    International Nuclear Information System (INIS)

    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

  7. A FOURIER OPTICS METHOD FOR CALCULATING STELLAR OCCULTATION LIGHT CURVES BY OBJECTS WITH THIN ATMOSPHERES

    International Nuclear Information System (INIS)

    A stellar occultation occurs when a solar system object passes in front of a distant star. The light curves resulting from stellar occultations can reveal many aspects of the obscuring object. For airless bodies, the diffraction light curve specifies the object's size, distance and, if several chords are observed, shape. Occultation light curves are especially sensitive to the presence of atmospheres; the refraction light curve is a function of the atmosphere's density, pressure, and temperature profiles. The goal of this paper is to develop a practical algorithm to model the simultaneous effects of diffraction and refraction for objects in which both phenomena are observable. The algorithm we present is flexible: it can be used to calculate light curves by objects with arbitrary shapes and arbitrary atmospheres (including the presence of opacity sources such as hazes), provided that the atmosphere can be represented by a thin screen with a phase delay and an opacity defined at each location in the screen. Because the algorithm is limited at present to thin atmospheres (in which rays from a star are bent but undergo virtually no translation as they pass through an atmosphere), the gas giants, Earth, Mars, and Venus are not treated. Examples of stellar occultations are presented for round or irregularly shaped objects having thin atmospheres of various column densities.

  8. Laboratory studies of thin films representative of atmospheric sulfate aerosol

    Science.gov (United States)

    Fortin, Tara Jean

    Sulfate aerosols are present globally in both the upper troposphere and lower stratosphere. These aerosols are of great interest because they have a profound influence on Earth's radiation balance, heterogeneous chemistry, and cloud formation mechanisms throughout the atmosphere. The magnitude of these effects is ultimately determined by the size, phase, and chemical composition of the aerosols themselves. This thesis explores some of the questions that remain concerning the phase of these aerosols under atmospheric conditions and the effects of their chemical composition on heterogeneous chemistry and cloud formation mechanisms. In the upper troposphere, cirrus clouds are thought to form via the homogeneous nucleation of ice out of dilute sulfate aerosols such as ammonium sulfate ((NH4)2SO4). To investigate this, the low-temperature phase behavior of ammonium sulfate films has been studied using Fourier transform infrared (FTIR) spectroscopy. Experiments performed as a function of increasing relative humidity demonstrate that a phase transition from crystalline (NH 4)2SO4 to a metastable aqueous solution can occur at temperatures below the eutectic at 254 K. However, on occasion, direct deposition of ice from the vapor phase was observed, possibly indicating selective heterogeneous nucleation. In addition to serving as nuclei for cirrus clouds, sulfate aerosols can participate in heterogeneous reactions. The interaction of HNO3 with ammonium sulfate has been investigated as a possible loss mechanism for gas-phase HNO3 using a Knudsen cell reactor coupled with transmission FTIR spectroscopy. The results show that HNO3 reacts with solid ammonium sulfate to produce ammonium nitrate and letovicite at 203 K. Furthermore, this reaction is enhanced as a function of relative humidity from 0 to 41%. In the lower stratosphere, polar stratospheric clouds (PSCs) are important for springtime ozone depletion. The vapor deposition of ice on sulfuric acid tetrahydrate (SAT) has

  9. Effect of CO2 on Atmospheric Corrosion of UNS G10190 Steel under Thin Electrolyte Film

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The atmospheric corrosion of UNS G10190 steel under a thin electrolyte film in the atmosphere polluted by CO2 has been studied in the lab using an atmospheric corrosion monitor(ACM) in combination with XRD and SEM observations of the surface of steel. The ACM study indicated that the corrosion rate of the steel increased with increasing carbon dioxide concentration. The XRD and SEM observations showed that no carbonate was found in the corrosion product on the steel surface. The corrosion product consisted of two layers, i. e., inner and outer layer. From the experimental results, it was concluded that CO2 played an enhancing role in the atmospheric corrosion of UNS G10190 steel. The film of the corrosion product showed slight protection.

  10. Spatial atmospheric atomic layer deposition of InxGayZnzO for thin film transistors

    NARCIS (Netherlands)

    Illiberi, A.; Cobb, B.; Sharma, A.; Grehl, T.; Brongersma, H.; Roozeboom, F.; Gelinck, G.; Poodt, P.

    2015-01-01

    We have investigated the nucleation and growth of InGaZnO thin films by spatial atmospheric atomic layer deposition. Diethyl zinc (DEZ), trimethyl indium (TMIn), triethyl gallium (TEGa), and water were used as Zn, In, Ga and oxygen precursors, respectively. The vaporized metal precursors have been c

  11. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  12. Pluto's atmosphere

    International Nuclear Information System (INIS)

    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

  13. 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

  14. Effect of annealing atmosphere on phase formation and electrical characteristics of bismuth ferrite thin films

    International Nuclear Information System (INIS)

    Bismuth ferrite thin films were deposited on Pt/Ti/SiO2/Si substrates by a soft chemical method and spin-coating technique. The effect of annealing atmosphere (air, N2 and O2) on the structure and electrical properties of the films are reported. X-ray diffraction analysis reveals that the film annealed in air atmosphere is a single-phase perovskite structure. The films annealed in air showed better crystallinity and the presence of a single BFO phase leading to lower leakage current density and superior ferroelectric hysteresis loops at room temperature. In this way, we reveal that BFO film crystallized in air atmosphere by the soft chemical method can be useful for practical applications, including nonvolatile digital memories, spintronics and data-storage media.

  15. Utilization of a thin layer electrochemical system to study the atmospheric corrosion

    International Nuclear Information System (INIS)

    In the radioactive wastes deep underground disposal, it is necessary to forecast the aging of metallic containers over millions of years. The deterioration results particularly of the atmospheric corrosion. The aim of this study is to propose models describing the corrosion processes during the storage, in order to evaluate the containers design. In this framework the influence of a thin electrolyte film in contact with the metal is studied. (A.L.B.)

  16. Time Invariant Surface Roughness Evolution during Atmospheric Pressure Thin Film Depositions

    OpenAIRE

    Thomas Merkh; Robert Spivey; Toh Ming Lu

    2016-01-01

    The evolution of thin film morphology during atmospheric pressure deposition has been studied utilizing Monte Carlo methods. Time invariant root-mean-squared roughness and local roughness morphology were both observed when employing a novel simulation parameter, modeling the effect of the experimental high pressure condition. This growth regime, where the surface roughness remains invariant after reaching a critical value, has not been classified by any existing universality class. An anti-sh...

  17. Thin layer chromatography/desorption atmospheric pressure photoionization-mass spectrometry of lipids

    Czech Academy of Sciences Publication Activity Database

    Rejšek, Jan; Vrkoslav, Vladimír; Cvačka, Josef

    Praha: Ústav organické chemie a biochemie AV ČR, 2016 - (Kuda, O.). s. 30 ISBN 978-80-86241-54-8. [Česká lipidomická konference /5./. 21.04.2016-22.04.2016, Praha] Institutional support: RVO:61388963 Keywords : desorption atmospheric pressure photoionization * ambient mass spectrometry * thin layer chromatography * lipids Subject RIV: CB - Analytical Chemistry, Separation

  18. 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...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design......” implications and qualities of the approach are identified through concrete examples of a design case, which also investigates the qualities and implications of addressing atmospheres both as design concern and user experience....

  19. Exoplanetary Atmospheres

    CERN Document Server

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  20. Staging atmospheres

    DEFF Research Database (Denmark)

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

    2015-01-01

    . Nevertheless, people’s experience of the environment is sought manipulated in a variety of contexts, often without offering a less ‘true’ experience of a situation than if it had not been manipulated by people. In fact, orchestrations of space are often central to sociality, politics and aesthetics. This...... introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  1. 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...

  2. Atmospheric Smell

    DEFF Research Database (Denmark)

    Stenslund, Anette

    awareness. Subsequently, visitor interviews revealed how a museum-staged hospital atmosphere of an art installation was directly addressed owing to its smell. Curiously, this observation speaks against prevailing literature portraying smell as the ‘mute sense’, and what is more, the museum display did not...... alter smell curatorially. Rather, smell was gestured through non-olfactory effects and it was put in words metonymically, gesturing a reversibly synaesthetic atmosphere of a hospital. Visitor conversations revealed how smell could be poignantly picked up in situ, yet not until frequenting the museum...

  3. ANNEALING OF POLYCRYSTALLINE THIN FILM SILICON SOLAR CELLS IN WATER VAPOUR AT SUB-ATMOSPHERIC PRESSURES

    Directory of Open Access Journals (Sweden)

    Peter Pikna

    2014-10-01

    Full Text Available Thin film polycrystalline silicon (poly-Si solar cells were annealed in water vapour at pressures below atmospheric pressure. PN junction of the sample was contacted by measuring probes directly in the pressure chamber filled with steam during passivation. Suns-VOC method and a Lock-in detector were used to monitor an effect of water vapour to VOC of the solar cell during whole passivation process (in-situ. Tested temperature of the sample (55°C – 110°C was constant during the procedure. Open-circuit voltage of a solar cell at these temperatures is lower than at room temperature. Nevertheless, voltage response of the solar cell to the light flash used during Suns-VOC measurements was good observable. Temperature dependences for multicrystalline wafer-based and polycrystalline thin film solar cells were measured and compared. While no significant improvement of thin film poly-Si solar cell parameters by annealing in water vapour at under-atmospheric pressures was observed up to now, in-situ observation proved required sensitivity to changing VOC at elevated temperatures during the process.

  4. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    . As a response to this situation, our design artefact, the interactive furniture Kidkit, invites children to become accustomed to the alarming sounds sampled from the ward while they are waiting in the waiting room. Our design acknowledges how atmospheres emerge as temporal negotiations between the...

  5. Laboratory analogues simulating Titan's atmospheric aerosols: Compared chemical compositions of grains and thin films

    Science.gov (United States)

    Carrasco, Nathalie; Jomard, François; Vigneron, Jackie; Etcheberry, Arnaud; Cernogora, Guy

    2016-09-01

    Two sorts of solid organic samples can be produced in laboratory experiments simulating Titan's atmospheric reactivity: grains in the volume and thin films on the reactor walls. We expect that grains are more representative of Titan's atmospheric aerosols, but films are used to provide optical indices for radiative models of Titan's atmosphere. The aim of the present study is to address if these two sorts of analogues are chemically equivalent or not, when produced in the same N2-CH4 plasma discharge. The chemical compositions of both these materials are measured by using elemental analysis, XPS analysis and Secondary Ion Mass Spectrometry. The main parameter probed is the CH4/N2 ratio to explore various possible chemical regimes. We find that films are homogeneous but significantly less rich in nitrogen and hydrogen than grains produced in the same experimental conditions. This surprising difference in their chemical compositions could be explained by the efficient etching occurring on the films, which stay in the discharge during the whole plasma duration, whereas the grains are ejected after a few minutes. The higher nitrogen content in the grains possibly involves a higher optical absorption than the one measured on the films, with a possible impact on Titan's radiative models.

  6. Oxidation of sputtered metallic Sn thin films using N2 atmospheric pressure plasma jets

    International Nuclear Information System (INIS)

    We investigated the oxidation of sputtered metallic Sn thin films annealed by N2 atmospheric pressure plasma jets (APPJs) with and without the introduction of ambient air to the reaction. As the APPJ annealing duration increased, the metallic Sn first oxidized into SnO, and then, a metallic Sn phase reappeared owing to the disproportionation reaction 4SnO → Sn3O4 + Sn → 2Sn + 2SnO2. The involvement of O2 from the ambient air led to more reactive oxidation of the thin films. APPJ annealing increased the band gap to ∼2.6–2.7 eV. All the annealed films show conductivity with unstable readings of carrier types because of the mixed phases of Sn, SnO, and possibly, some SnO2 in the films. (paper)

  7. Atmospheric Neutrinos

    CERN Document Server

    Gaisser, Thomas K

    2016-01-01

    In view of the observation by IceCube of high-energy astrophysical neutrinos, it is important to quantify the uncertainty in the background of atmospheric neutrinos. There are two sources of uncertainty, the imperfect knowledge of the spectrum and composition of the primary cosmic rays that produce the neutrinos and the limited understanding of hadron production, including charm, at high energy. This paper is an overview of both aspects.

  8. Effect of ambient pressure and radiation reabsorption of atmosphere on the flame spreading over thermally thin combustibles in microgravity

    Institute of Scientific and Technical Information of China (English)

    DU; Wenfeng; (杜文峰); HU; Wenrui; (胡文瑞)

    2003-01-01

    For the flame spread over thermally thin combustibles in an atmosphere, if the atmosphere cannot emit and absorb the thermal radiation (e.g. for atmosphere of O2-N2), the conductive heat transfer from the flame to the fuel surface dominates the flame spread at lower ambient atmosphere. As the ambient pressure increases, the flame spread rate increases, and the radiant heat transfer from the flame to the fuel surface gradually becomes the dominant driving force for the flame spread. In contrast, if the atmosphere is able to emit and absorb the thermal radiation (e.g. for atmosphere of O2-CO2), at lower pressure, the heat transfer from flame to the fuel surface is enhanced by the radiation reabsorption of the atmosphere at the leading edge of the flame, and both conduction and thermal radiation play important roles in the mechanism of flame spread. With the increase in ambient pressure, the oxygen diffuses more quickly from ambient atmosphere into the flame, the chemical reaction in the flame is enhanced, and the flame spread rate increases. When the ambient pressure is greater than a critical value, the thermal radiation from the flame to the solid surface is hampered by the radiation reabsorption of ambient atmosphere with the further increase in ambient pressure. As a result, with the increase in ambient pressure, the flame spread rate decreases and the heat conduction gradually dominates the flame spread over the fuel surface.

  9. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    International Nuclear Information System (INIS)

    Graphical abstract: The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. - Highlights: • Compactness and smoothness of the films were enhanced after sulfur annealing. • Micro-strain values of some films were improved after sulfur annealing. • Dislocation density values of some films were improved after sulfur annealing. • Band gap values of the films were improved after sulfur annealing. - Abstract: Cadmium sulfide (CdS) thin films were prepared on glass substrates by using chemical bath deposition (CBD) technique. The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. Compactness and smoothness of the films (especially for pH 10.5 and 11) enhanced after sulfur annealing. pH value of the precursor solution remarkably affected the roughness, uniformity and particle sizes of the films. Based on the analysis of X-ray diffraction (XRD) patterns of the films, micro-strain and dislocation density values of the sulfur-annealed films (pH 10.5 and 11) were found to be lower than those of air-annealed films. Air-annealed films (pH 10.5, 11 and 11.5) exhibited higher transmittance than sulfur-annealed films in the wavelength region of 550–800 nm. Optical band gap values of the films were found between 2.31 eV and 2.36 eV

  10. Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

    International Nuclear Information System (INIS)

    Silicon (Si) thin films were produced using an aerosol assisted atmospheric pressure chemical vapor deposition technique with liquid hydrosilane precursors cyclopentasilane (CPS, Si5H10) and cyclohexasilane (CHS, Si6H12). Thin films were deposited at temperatures between 300 and 500 °C, with maximum observed deposition rates of 55 and 47 nm/s for CPS and CHS, respectively, at 500 °C. Atomic force microscopic analyses of the films depict smooth surfaces with roughness of 4–8 nm. Raman spectroscopic analysis indicates that the Si films deposited at 300 °C and 350 °C consist of a hydrogenated amorphous Si (a-Si:H) phase while the films deposited at 400, 450, and 500 °C are comprised predominantly of a hydrogenated nanocrystalline Si (nc-Si:H) phase. The wide optical bandgaps of 2–2.28 eV for films deposited at 350–400 °C and 1.7–1.8 eV for those deposited at 450–500 °C support the Raman data and depict a transition from a-Si:H to nc-Si:H. Films deposited at 450 oC possess the highest photosensitivity of 102–103 under AM 1.5G illumination. Based on the growth model developed for other silanes, we suggest a mechanism that governs the film growth using CPS and CHS. - Highlights: • Si films via AA-APCVD are realized using cyclopentasilane (CPS) and cyclohexasilane (CHS). • Low activation energies of CPS and CHS allow Si thin films at low temperatures (300 °C). • High growth rates of 47–55 nm/s were obtained at 500 °C • Near device quality Si thin films with 2–3 orders of photosensitivity • Si thin films via AA-APCVD are amenable to continuous roll-to-roll manufacturing

  11. Deposition of zinc oxide thin films by an atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    The ZnO thin film deposition process by using an atmospheric pressure (AP) plasma jet is studied. In this process, nebulized ZnCl2 solution is sprayed into the downstream of the nitrogen plasma jet to perform thin film deposition. X-ray diffraction analysis confirms that this AP jet has the capability to convert ZnCl2 solution to well-crystallized ZnO thin films with a hexagonal wurtzite structure in a short time. This film exhibits a smooth and mirror-like appearance visually. Scanning electron microscopy and atomic force microscopy show that the deposited film is dense and continuous with a root mean square surface roughness of 8.6 nm. A 1.29 nm/s deposition rate is obtained using this process. Given the fast deposition rate, we believe that both the temperature and the reactivity of the plasma play important roles. A ZnO film on a larger substrate is fabricated, which suggests the process capability in large area and continuous processing applications.

  12. Deposition of hard thin films from HMDSO in atmospheric pressure dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Trunec, D; Zajickova, L; BursIkova, V; Studnicka, F; Stahel, P; Prysiazhnyi, V; Navratil, Z; Franta, D [Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Perina, V [Institute of Nuclear Physics, Academy of Sciences of the Czech Republic, 250 68 Rez (Czech Republic); Houdkova, J, E-mail: trunec@physics.muni.c [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague (Czech Republic)

    2010-06-09

    An atmospheric pressure dielectric barrier discharge burning in nitrogen with a small admixture of hexamethyldisiloxane (HMDSO) was used for the deposition of thin organosilicon films. The thin films were deposited on glass, silicon and polycarbonate substrates, and the substrate temperature during the deposition process was increased up to values within the range 25-150 {sup 0}C in order to obtain hard SiO{sub x}-like thin films. The properties of the discharge were studied by means of optical emission spectroscopy and electrical measurements. The deposited films were characterized by the Rutherford backscattering and elastic recoil detection methods, x-ray photoelectron spectroscopy, infrared spectroscopy measurements, ellipsometry and the depth sensing indentation technique. It was found that the films' properties depend significantly on the substrate temperature at deposition. An increase in substrate temperature from 25 to 150 {sup 0}C led to an increase in film hardness from 0.4 to 7 GPa and the film chemical composition changed from CH{sub x}Si{sub y}O{sub z} to SiO{sub x}H{sub y}. The films were transparent in the visible range.

  13. Radiative properties of magnetic neutron stars with metallic surfaces and thin atmospheres

    CERN Document Server

    Potekhin, A Y; van Adelsberg, M; Werner, K

    2012-01-01

    The goal of this work is to develop a simple analytic description of the emission properties (spectrum and polarization) of the condensed, strongly magnetized surface of neutron stars. We have improved the method of van Adelsberg et al. (2005) (arXiv:astro-ph/0406001) for calculating the spectral properties of condensed magnetized surfaces. Using the improved method, we calculate the reflectivity of an iron surface at magnetic field strengths B \\sim (10^{12} - 10^{14}) G, with various inclinations of the magnetic field lines and radiation beam with respect to the surface and each other. We construct analytic expressions for the emissivity of this surface as functions of the photon energy, magnetic field strength, and the three angles that determine the geometry of the local problem. Using these expressions, we calculate X-ray spectra for neutron stars with condensed iron surfaces covered by thin partially ionized hydrogen atmospheres. We develop simple analytic descriptions of the intensity and polarization o...

  14. Time Invariant Surface Roughness Evolution during Atmospheric Pressure Thin Film Depositions.

    Science.gov (United States)

    Merkh, Thomas; Spivey, Robert; Lu, Toh Ming

    2016-01-01

    The evolution of thin film morphology during atmospheric pressure deposition has been studied utilizing Monte Carlo methods. Time invariant root-mean-squared roughness and local roughness morphology were both observed when employing a novel simulation parameter, modeling the effect of the experimental high pressure condition. This growth regime, where the surface roughness remains invariant after reaching a critical value, has not been classified by any existing universality class. An anti-shadowing growth mechanism responsible for this regime occurs when particles undergo binary collisions beneath the surface apexes. Hence, this mechanism is applicable when the mean free path of the depositing species is comparable to the amplitude of the surface features. Computationally this has been modeled by allowing particles to change direction at a specified height above the local film surface. This modification of the incoming flux trajectory consequently has a dramatic smoothening effect, and the resulting surfaces appear in agreement with recent experimental observations. PMID:26814165

  15. Obtaining Au thin films in atmosphere of reactive nitrogen through magnetron sputtering

    Science.gov (United States)

    Quintero, J. H.; Ospina, R.; Mello, A.

    2016-02-01

    4d and 5d series of the transition metals are used to the obtaining nitrides metallic, due to the synthesis of PtN, AgN and AuN in the last years. Different nitrides are obtained in the Plasma Assisted Physics Vapour Deposition system, due to its ionization energy which is necessary for their formation. In this paper a Magnetron Sputtering system was used to obtain Au thin films on Si wafers in Nitrogen atmosphere. The substrate temperature was varied between 500 to 950°C. The samples obtained at high temperatures (>500°C) show Au, Si and N elements, as it is corroborated in the narrow spectrum obtained for X-Ray Photoelectron Spectroscopy; besides the competition of orientation crystallographic texture between (111) and (311) directions was present in the X-Ray Diffraction analysis to the sample heated at 950°C.

  16. Research update : Atmospheric pressure spatial atomic layer deposition of ZnO thin films : reactors, doping and devices

    OpenAIRE

    Hoye, Robert L.Z.; David Muñoz-Rojas; Nelson, Shelby F.; Andrea Illiberi; Paul Poodt; Fred Roozeboom; MacManus-Driscoll, Judith L

    2015-01-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-S...

  17. Study of thin clouds at CNR-IMAA Atmospheric Observatory (CIAO

    Directory of Open Access Journals (Sweden)

    Marco Rosoldi

    2014-01-01

    Full Text Available Space-based measurements allow us to study atmospheric variables at global scale, but ground-based observations are necessary for calibration and validation [GCOS, 2006]. Upcoming satellite missions aim at showing the benefit coming from the availability of technological improvements and innovations. However, research is necessary to improve retrieval algorithms of atmospheric variables and to assess the real advances in the knowledge of weather and climate. Quality-controlled vertical profiles of atmospheric key variables provided by ground-based advanced atmospheric observatories represent the optimal basis for the satellite cal/val programs. So far, atmospheric observatories are working towards the development of new observation strategies and the full exploitation of the synergy among active and passive profiling sensors. This is highly relevant for the new generation satellites equipped with multiple sensors on board the same observation platform. [...

  18. Morphology and photocatalysis of mesoporous titania thin films annealed in different atmosphere for degradation of methyl orange

    Science.gov (United States)

    Ma, Qing; Qin, Tian Pang; Liu, Shao Jun; Weng, Lv Qian; Dong, Wen Yi

    2011-07-01

    The effect of different annealing atmosphere on the morphology and photocatalytic activity of mesoporous TiO2 thin films by dip-coating technique is investigated. The annealing temperature and atmosphere causes significant change of the morphology, thermal stability, photoluminescence, and photocatalytic properties of mesoporous TiO2 films. As-prepared mesoporous thin films have an amorphous structure that is transformed to crystalline TiO2 with well-maintained mesoporous structure at 450°C in various annealing atmosphere except that the mesoporous structure is fully destroyed for films annealed in air. Films annealed in N2 show the enhanced UV photodegradation of methyl orange (MO) resulting from the enhanced crystallinity in these films evidenced by XRD and Raman spectra. These findings can be used to tailor the structure and morphology of mesoporous TiO2 films and thus improve their photocatalytic activity for efficient removal of dye effluents in wastewater.

  19. Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Guruvenket, Srinivasan, E-mail: guruvenket.srinivasan@ndsu.edu [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Hoey, Justin M.; Anderson, Kenneth J.; Frohlich, Matthew T.; Sailer, Robert A. [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Boudjouk, Philip [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Department of Chemistry and Biochemistry, Ladd-Dunbar Hall, North Dakota State University, Fargo, ND 58102 (United States)

    2015-08-31

    Silicon (Si) thin films were produced using an aerosol assisted atmospheric pressure chemical vapor deposition technique with liquid hydrosilane precursors cyclopentasilane (CPS, Si{sub 5}H{sub 10}) and cyclohexasilane (CHS, Si{sub 6}H{sub 12}). Thin films were deposited at temperatures between 300 and 500 °C, with maximum observed deposition rates of 55 and 47 nm/s for CPS and CHS, respectively, at 500 °C. Atomic force microscopic analyses of the films depict smooth surfaces with roughness of 4–8 nm. Raman spectroscopic analysis indicates that the Si films deposited at 300 °C and 350 °C consist of a hydrogenated amorphous Si (a-Si:H) phase while the films deposited at 400, 450, and 500 °C are comprised predominantly of a hydrogenated nanocrystalline Si (nc-Si:H) phase. The wide optical bandgaps of 2–2.28 eV for films deposited at 350–400 °C and 1.7–1.8 eV for those deposited at 450–500 °C support the Raman data and depict a transition from a-Si:H to nc-Si:H. Films deposited at 450 {sup o}C possess the highest photosensitivity of 10{sup 2}–10{sup 3} under AM 1.5G illumination. Based on the growth model developed for other silanes, we suggest a mechanism that governs the film growth using CPS and CHS. - Highlights: • Si films via AA-APCVD are realized using cyclopentasilane (CPS) and cyclohexasilane (CHS). • Low activation energies of CPS and CHS allow Si thin films at low temperatures (300 °C). • High growth rates of 47–55 nm/s were obtained at 500 °C • Near device quality Si thin films with 2–3 orders of photosensitivity • Si thin films via AA-APCVD are amenable to continuous roll-to-roll manufacturing.

  20. Using In-Situ Deposition of Metallic Thin Films on Mars to Monitor Atmospheric H20

    Science.gov (United States)

    Zent, A. P.; Quinn, R. C.; Grunthaner, F. G.; Towner M.; Zanecki, J.; Ringrose, T.

    2005-01-01

    We describe the use of a novel sensor, designed to characterize the reactive nature of the Martian atmosphere, to also characterize the instantaneous abundance of atmospheric H,O. The sensor deposits, in situ, a thin silver film onto a sapphire substrate and monitors oxidation by measuring resistance of the Ag film during both deposition and subsequent oxidation [1,2]. . The evaporation source is placed in the center of a hollow, open-ended tube. On flash heating the source, evaporated metallic silver rapidly reacts with oxidizing gases in the tube, depositing on the tube walls as a resisitive Ag oxide film. Unoxidized silver deposits over the Ag oxides, once the oxidizing gases in the vicinity of the source have been consumed. Since the ends of the tube are open, atmospheric gases in the tube cause a time delay as the evaporated silver initially reacts with the available O2, and H2O; once oxidizing gases in the tube are significantly depleted, a silver film closes the chemiresistor circuit. In principle this operation mode provides a repeatable measure of the variable H2O abundance, since O2, levels are constant in the atmosphere. To explore the utility of the instrument as an H2O sensor, predict its behavior, and identify possible failure modes, we developed a numerical model of the instrument, and exercised it for Mars conditions. The model predicts the behavior of the electrical circuit, the temperature dependence of resistivity for each component, and the resultant Joule heating. The model balances Joule heating against radiation, sensible heat loss to ambient CO2, and, latent heat loss from sublimating Ag. The flux of Ag atoms from the source is tracked continuously. In the gas phase, the number density of Ag, O2, and H2O is calculated, along with their reaction rates on collision. The model suggests that Ag substantially depletes H2O only near the center of the tube. The model supports the hypothesis that the onset of high conductivity between the A u

  1. Tuning phase transition temperature of VO2 thin films by annealing atmosphere

    International Nuclear Information System (INIS)

    A simple new way to tune the optical phase transition temperature of VO2 films was proposed by only controlling the pressure of oxygen during the annealing process. Vanadium films were deposited on glass by a large-scale magnetron sputtering coating system and then annealed in appropriate oxygen atmosphere to form the VO2 films. The infrared transmission change (at 2400 nm) is as high as 58% for the VO2 thin film on the glass substrate, which is very good for tuning infrared radiation and energy saving as smart windows. The phase transition temperature of the films can be easily tuned from an intrinsic temperature to 44.7 °C and 40.2 °C on glass and sapphire by annealing oxygen pressure, respectively. The mechanism is: V3+ ions form in the film when under anaerobic conditions, which can interrupt the V4+ chain and reduce the phase transition temperature. The existence of V3+ ions has been observed by x-ray photoelectron spectroscopy (XPS) experiments as proof. (paper)

  2. Discovering Pluto's atmosphere

    International Nuclear Information System (INIS)

    Observations of the occultation of an obscure 12th-magnitude star in eastern Virgo by Pluto on June 9, 1988 are discussed. The occultation was observed by astronomers aboard NASA's Kuiper Airborne Observatory flying over the Pacific. The prediction of the occultation and the results of the observations are examined. The study demonstrated that Pluto has a thin atmosphere and that its diameter is about two-thirds that of the moon

  3. Atmospheric pressure chemical vapour deposition of thermochromic tungsten doped vanadium dioxide thin films for use in architectural glazing

    OpenAIRE

    Blackman, C. S.; Piccirillo, C.; Binions, R.; Parkin, I. P.

    2009-01-01

    Atmospheric pressure chemical vapour deposition of VCl4, WCl6 and water at 550 degrees C lead to the production of high quality tungsten doped vanadium dioxide thin films. Careful control of the gas phase precursors allowed for tungsten doping up to 8 at.%. The transition temperature of the thermochromic switch was tunable in the range 55 degrees C to - 23 degrees C. The films were analysed using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spect...

  4. How common are aeolian processes on planetary bodies with very thin atmospheres?

    Science.gov (United States)

    Pähtz, Thomas; Duran, Orencio

    2016-04-01

    Observations from the Voyager 2, New Horizons, and Rosetta missions indicate that aeolian surface features, such as ripples and dunes, do not only occur on the surfaces of Earth, Mars, and Titan, but seemingly also on the surfaces of planetary bodies with extremely thin atmospheres, such as Triton, Pluto, and the comet 67P/Churyumov-Gerasimenko. This is highly intriguing since the saltation-threshold wind shear velocities predicted for these bodies from standard saltation-threshold models are so large that wind erosion actually should not occur. Here, guided by coupled DEM/RANS numerical simulations of sediment transport in Newtonian fluid using the numerical model by Duran et al. (POF 24, 103306, 2012), we propose an analytical model based entirely on physical princinples that predicts the minimal fluid speeds required to sustain sediment transport in Newtonian fluid. The analytical model is consistent with measurements of the transport threshold in water and Earth's air and with a recent observational estimate of the threshold on Mars. When applied to Triton and Pluto, it predicts threshold wind shear velocities (ut) of about 1-3m/s, which is comparable to wind shear occurring during storms on Earth and Mars, for particles with diameters (d) within the range d ∈ [200,3000]μm. The minimal values (≈ 1m/s) are thereby predicted for surprisingly large particles with d ≈ 2000μm. When applied to 67P/Churyumov-Gerasimenko, the analytical model predicts threshold wind shear velocities that are fairly extreme (e.g., ut = 45m/s for d = 1cm), but nonetheless consistent with wind shear velocities estimated to occur on this comet. From our results, we conclude that surface-shaping wind erosion and thus the occurrence of aeolian surface features might be much more common on low-air-density planetary bodies than previously thought.

  5. Effect of Annealing Atmosphere on the Properties of Electrochemically Deposited Cu2ZnSnS4 (CZTS) Thin Films

    OpenAIRE

    Pawar, B. S.; S. M. Pawar; Gurav, K. V.; Shin, S. W.; Lee, J.Y.; S. S. KOLEKAR; Kim, J. H.

    2011-01-01

    The Cu2ZnSnS4 (CZTS) thin films have been electrochemically deposited from a weak acidic medium (pH 4.50~5.00) onto Mo- coated and ITO-coated glass substrate by using single-step electrodeposition method. Trisodium citrate was used as a complexing agent. The effect of annealing atmospheres such as Ar, N2, N2+H2S on the structural, morphological, compositional, and optical properties of CZTS thin films has been investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), ...

  6. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean.

    Science.gov (United States)

    Arrieta, Jesús M; Duarte, Carlos M; Sala, M Montserrat; Dachs, Jordi

    2015-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget. PMID:26834717

  7. Out of thin air: Microbial utilization of atmospheric gaseous organics in the surface ocean

    Directory of Open Access Journals (Sweden)

    Jesus M Arrieta

    2016-01-01

    Full Text Available Volatile and semi-volatile gas-phase organic carbon (GOC is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 to 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidising marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  8. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    Science.gov (United States)

    Arrieta, Jesús M.; Duarte, Carlos M.; Sala, M. Montserrat; Dachs, Jordi

    2016-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget. PMID:26834717

  9. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    KAUST Repository

    Arrieta, Jesus

    2016-01-20

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  10. Nucleation of atmospheric particles

    OpenAIRE

    Curtius J

    2009-01-01

    Two types of particles exist in the atmosphere, primary and secondary particles. While primary particles such as soot, mineral dust, sea salt particles or pollen are introduced directly as particles into the atmosphere, secondary particles are formed in the atmosphere by condensation of gases. The formation of such new aerosol particles takes place frequently and at a broad variety of atmospheric conditions and geographic locations. A considerable fraction of the atmospheric particles is form...

  11. Laboratory Studies of Hydrocarbon Nucleation on Tholin Particles and Thin Organic Films: Application to Titan's Atmosphere

    Science.gov (United States)

    Curtis, Daniel B.; Glandorf, David L.; Toon, Owen B.; Tolbert, Margaret A.; McKay, Christopher P.; Khare, Bishun N.

    2001-01-01

    Titan, Saturn's largest satellite, has a thick nitrogen/methane atmosphere. In Titan's lower atmosphere, methane is saturated or supersaturated with respect to nucleation and may form clouds. To better characterize the properties of Titan's methane clouds we have measured the saturation ratio required to obtain butane nucleation, S (sub crit), on Titan tholin material and organic films. We find a critical saturation ratio for butane on tholin particles of S (sub crit) = 1.40, suggesting high supersaturations are required for nucleation. If methane is similar to butane, we expect high supersaturations of methane as well. This could favor the formation of a small number of large particles, consistent with recent measurements of methane rain on Titan.

  12. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Hoye, Robert L. Z., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk; MacManus-Driscoll, Judith L., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Muñoz-Rojas, David [LMGP, University Grenoble-Alpes, CNRS, F-3800 Grenoble (France); Nelson, Shelby F. [Kodak Research Laboratories, Eastman Kodak Company, Rochester, New York 14650 (United States); Illiberi, Andrea; Poodt, Paul [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Roozeboom, Fred [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB (Netherlands)

    2015-04-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics.

  13. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    International Nuclear Information System (INIS)

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics

  14. Thin film deposition at atmospheric pressure using dielectric barrier discharges: Advances on three-dimensional porous substrates and functional coatings

    Science.gov (United States)

    Fanelli, Fiorenza; Bosso, Piera; Mastrangelo, Anna Maria; Fracassi, Francesco

    2016-07-01

    Surface processing of materials by atmospheric pressure dielectric barrier discharges (DBDs) has experienced significant growth in recent years. Considerable research efforts have been directed for instance to develop a large variety of processes which exploit different DBD electrode geometries for the direct and remote deposition of thin films from precursors in gas, vapor and aerosol form. This article briefly reviews our recent progress in thin film deposition by DBDs with particular focus on process optimization. The following examples are provided: (i) the plasma-enhanced chemical vapor deposition of thin films on an open-cell foam accomplished by igniting the DBD throughout the entire three-dimensional (3D) porous structure of the substrate, (ii) the preparation of hybrid organic/inorganic nanocomposite coatings using an aerosol-assisted process, (iii) the DBD jet deposition of coatings containing carboxylic acid groups and the improvement of their chemical and morphological stability upon immersion in water.

  15. Atmospheric composition change: Ecosystems–Atmosphere interactions

    DEFF Research Database (Denmark)

    Fowler, D.; Pilegaard, Kim; Sutton, M.A.;

    2009-01-01

    Ecosystems and the atmosphere: This review describes the state of understanding the processes involved in the exchange of trace gases and aerosols between the earth's surface and the atmosphere. The gases covered include NO, NO2, HONO, HNO3, NH3, SO2, DMS, Biogenic VOC, O3, CH4, N2O and particles...

  16. Statistics in Atmospheric Science

    OpenAIRE

    Solow, Andrew R.

    2003-01-01

    This paper reviews the use of statistical methods in atmospheric science. The applications covered include the development, assessment and use of numerical physical models of the atmosphere and more empirical analysis unconnected to physical models.

  17. 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...

  18. Planetary Atmospheric Electricity

    CERN Document Server

    Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M

    2008-01-01

    This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...

  19. Earth's changeable atmosphere

    Science.gov (United States)

    2016-06-01

    Billions of years ago, high atmospheric greenhouse gas concentrations were vital to life's tenuous foothold on Earth. Despite new constraints, the composition and evolution of Earth's early atmosphere remains hazy.

  20. Atmospheric Lepton Fluxes

    CERN Document Server

    Gaisser, Thomas K

    2014-01-01

    This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric $\

  1. Mirador - Atmospheric Composition

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Atmospheric Composition is focused on the composition of Earth's atmosphere in relation to climate prediction, solar effects,...

  2. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography

    OpenAIRE

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2015-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1 W, was used. The combination of the simple, low-budget laser pointer and the FAP...

  3. Beam tests of a thin dual-readout calorimeter for detecting cosmic rays outside the Earth's atmosphere

    International Nuclear Information System (INIS)

    Cosmic ray experiments outside the Earth's atmosphere are subject to very severe restrictions on the mass of the instruments. Therefore, it is important that the experimental information that can be obtained per unit detector mass is maximized. In this paper, we describe tests of a thin (1.4λint deep) hadron calorimeter that was designed with this goal in mind. This detector was equipped with two independent active media, which provided complementary information on the showering hadrons. It is shown that by combining the information from these media it was possible to reduce the effects of the dominant leakage fluctuations on the calorimeter performance

  4. Fabrication of transparent antifouling thin films with fractal structure by atmospheric pressure cold plasma deposition.

    Science.gov (United States)

    Miyagawa, Hayato; Yamauchi, Koji; Kim, Yoon-Kee; Ogawa, Kazufumi; Yamaguchi, Kenzo; Suzaki, Yoshifumi

    2012-12-21

    Antifouling surface with both superhydrophobicity and oil-repellency has been fabricated on glass substrate by forming fractal microstructure(s). The fractal microstructure was constituted by transparent silica particles of 100 nm diameter and transparent zinc-oxide columns grown on silica particles by atmospheric pressure cold plasma deposition. The sample surface was coated with a chemically adsorbed monomolecular layer. We found that one sample has the superhydrophobic ability with a water droplet contact angle of more than 150°, while another sample has a high transmittance of more than 85% in a wavelength range from 400 to 800 nm. PMID:23186100

  5. Intensifying the Atmospheric

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä

    2012-01-01

    understanding of atmospheres as aesthetically ‘radiating’ from the surfaces of space, thinks physiognomically, the article argues for a spatial morphological perspective on atmospheres. Thus, post-phenomeno¬logically, it is argued that the atmospheric given is given by the density of pedestrians, which are...

  6. From Sub-Neptunes to Earth-like Exoplanets: Modeling Optically Thick and Thin Planetary Atmospheres

    Science.gov (United States)

    Chen, Howard; Rogers, Leslie; Kasting, James

    2016-01-01

    Exoplanet surveys have revealed a wide diversity of planet properties in the Milky Way. Here, we present the results from two projects modeling planet atmospheres; one considering the hydrogen/helium envelopes of sub-Neptune-mass planets, and the other, the climate of Earth-like planets.First, we modify the state-of-the-art stellar evolution code Modules for Experimental Astrophysics (MESA) to model the thermal evolution of gaseous Sub-Neptune sized planets. Including photo-evaporation, we find a resulting convergent evolution trend that could potentially imprint itself on the close-in planet population as a preferred H/He mass fraction of 0.5-3%.We also use an updated version of a radiative-convective climate model to calculate the upper atmospheric conditions of planets warmer than the present Earth. In our simulations, cold, dry stratospheres are predicted at lower surface temperatures. However, onset of moist greenhouse water-loss limit to habitability emerges when the surface temperature reaches above 350 K. This result places constraint on a more accurate calculation of the inner edge of the habitable zone around Sun-like stars.

  7. Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-01-01

    Full Text Available This work presents a study on the preparation of plasma-polymerized aniline (pPANI nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, gas chromatography-mass spectrometry (GC-MS, and gel permeation chromatography (GPC techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw, about 533 kDa with 1.9 polydispersity index (PDI. This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

  8. Nonisothermal Pluto atmosphere models

    International Nuclear Information System (INIS)

    The present thermal profile calculation for a Pluto atmosphere model characterized by a high number fraction of CH4 molecules encompasses atmospheric heating by solar UV flux absorption and conductive transport cooling to the surface of Pluto. The stellar occultation curve predicted for an atmosphere of several-microbar surface pressures (which entail the existence of a substantial temperature gradient close to the surface) agrees with observations and implies that the normal and tangential optical depth of the atmosphere is almost negligible. The minimum period for atmospheric methane depletion is calculated to be 30 years. 29 refs

  9. Ferroelectric properties of dysprosium-doped Bi4Ti3O12 thin films crystallized in various atmospheres

    Institute of Scientific and Technical Information of China (English)

    CHENG Chuan-pin; TANG Ming-hua; YE Zhi; ZHOU Yic-hun; ZHENG Xue-jun; ZHONG Xiang-li; HU Zeng-shun

    2006-01-01

    Dysprosium-doped Bi4Ti3O12 (Bi3.4Dy0.6Ti3O12,BDT) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si(111) substrates by chemical solution deposition (CSD) and crystallized in nitrogen,air and oxygen atmospheres,respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure,the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃,exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 μC/cm2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures (600-750 ℃) were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However,the polarization of the films is not monotonous function of the annealing temperature.

  10. Antifouling Transparent ZnO Thin Films Fabricated by Atmospheric Pressure Cold Plasma Deposition

    Science.gov (United States)

    Suzaki, Yoshifumi; Du, Jinlong; Yuji, Toshifumi; Miyagawa, Hayato; Ogawa, Kazufumi

    2015-09-01

    One problem with outdoor-mounted solar panels is that power generation efficiency is reduced by face plate dirt; a problem with electronic touch panels is the deterioration of screen visibility caused by finger grease stains. To solve these problems, we should fabricate antifouling surfaces which have superhydrophobic and oil-repellent properties without spoiling the transparency of the transparent substrate. In this study, an antifouling surface with both superhydrophobicity and oil-repellency was fabricated on a glass substrate by forming a fractal microstructure. The fractal microstructure was constituted of transparent silica particles 100 nm in diameter and transparent zinc-oxide columns grown on silica particles through atmospheric pressure cold plasma deposition; the sample surface was coated with a chemically adsorbed monomolecular layer. Samples were obtained which had a superhydrophobic property (with a water droplet contact angle of more than 150°) and a high average transmittance of about 90% (with wavelengths ranging from 400 nm to 780 nm).

  11. Fabrication of Titanium Dioxide Thin Films by DBD-CVD Under Atmosphere

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xi-wen; GUO Yu; HAN Gao-rong

    2007-01-01

    Titanium dioxide films were firstly deposited on glass substrate by DBD-CVD (dielectric barrier discharge enhanced chemical vapor deposition) technique.The structure of the films was investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM).TiO2 films deposited under atmosphere pressure show preferred orientation,and exhibit columnar-like structure,while TiO2 films deposited under low gas pressure show no preferred orientation.The columnar-like structure with preferred orientation exhibits higher photocatalytic efficiency,since the columnar structure has larger surface area.However,it contributes little to the improvement of hydrophilicity. DBD-CVD is an alternative method to prepare photocatalytic TiO2 for its well-controllable property.

  12. Atmospheric-pressure plasma-enhanced chemical vapor deposition of electrochromic organonickel oxide thin films with an atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    Deposition of electrochromic organonickel oxide (NiOxCy) films onto glass/indium tin oxide (ITO) substrates using atmospheric-pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet under various precursor injection angles is investigated. A precursor [nickelocene, Ni(C5H5)2] vapor, carried by argon gas and mixed with oxygen gas, is injected into an air plasma torch for the deposition of NiOxCy films by a short exposure of the substrate, 20 s, in the plasma. Uniform light modulation on glass/ITO/NiOxCy is produced while the moving glass/ITO substrate is exposed to the plasma torch at room temperature (∼ 23 °C) and under atmospheric pressure. Light modulation with up to a 40.9% transmittance variation at a wavelength of 513.9 nm under Li+ intercalation and de-intercalation in a 1 M LiClO4–propylene carbonate electrolyte is achieved. - Highlights: ► Rapid deposition of electrochromic NiOxCy film by atmospheric pressure plasma jet ► Uniform light modulation on NiOxCy film is produced. ► Nano-grains in NiOxCy films offer fast coloration and bleaching

  13. Pluto's atmosphere near perihelion

    International Nuclear Information System (INIS)

    A recent stellar occultation has confirmed predictions that Pluto has an atmosphere which is sufficiently thick to uniformly envelope the planet and to extend far above the surface. Pluto's atmosphere consists of methane and perhaps other volatile gases at temperatures below their freezing points; it should regulate the surface temperature of its volatile ices to a globally uniform value. As Pluto approaches and passes through perihelion, a seasonal maximum in the atmospheric bulk and a corresponding minimum in the exposed volatile ice abundance is expected to occur. The lag in maximum atmospheric bulk relative to perihelion will be diagnostic of the surface thermal properties. An estimate of Pluto's atmospheric bulk may result if a global darkening (resulting from the disappearance of the seasonally deposited frosts) occurs before the time of maximum atmospheric bulk. The ice deposited shortly after perihelion may be diagnostic of the composition of Pluto's volatile reservoir

  14. Measurement of the Atmospheric $\

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  15. Atmospheric Circulation of Exoplanets

    CERN Document Server

    Showman, Adam P; Menou, Kristen

    2009-01-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric d...

  16. Fair weather atmospheric electricity

    International Nuclear Information System (INIS)

    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.

  17. Photochemistry in planetary atmospheres

    Science.gov (United States)

    Levine, J. S.; Graedel, T. E.

    1981-01-01

    Widely varying paths of evolutionary history, atmospheric processes, solar fluxes, and temperatures have produced vastly different planetary atmospheres. The similarities and differences between the earth atmosphere and those of the terrestrial planets (Venus and Mars) and of the Jovian planets are discussed in detail; consideration is also given to the photochemistry of Saturn, Uranus, Pluto, Neptune, Titan, and Triton. Changes in the earth's ancient atmosphere are described, and problems of interest in the earth's present troposphere are discussed, including the down wind effect, plume interactions, aerosol nucleation and growth, acid rain, and the fate of terpenes. Temperature fluctuations in the four principal layers of the earth's atmosphere, predicted decreases in the ozone concentration as a function of time, and spectra of particles in the earth's upper atmosphere are also presented. Finally, the vertical structure of the Venus cloud system and the thermal structure of the Jovian planets are shown graphically.

  18. Adhesive Stretchable Printed Conductive Thin Film Patterns on PDMS Surface with an Atmospheric Plasma Treatment.

    Science.gov (United States)

    Li, Chun-Yi; Liao, Ying-Chih

    2016-05-11

    In this study, a plasma surface modification with printing process was developed to fabricate printed flexible conductor patterns or devices directly on polydimethylsiloxane (PDMS) surface. An atmospheric plasma treatment was first used to oxidize the PDMS surface and create a hydrophilic silica surface layer, which was confirmed with photoelectron spectra. The plasma operating parameters, such as gas types and plasma powers, were optimized to obtain surface silica layers with the longest lifetime. Conductive paste with epoxy resin was screen-printed on the plasma-treated PDMS surface to fabricate flexible conductive tracks. As a result of the strong binding forces between epoxy resin and the silica surface layer, the printed patterns showed great adhesion on PDMS and were undamaged after several stringent adhesion tests. The printed conductive tracks showed strong mechanical stability and exhibited great electric conductivity under bending, twisting, and stretching conditions. Finally, a printed pressure sensor with good sensitivity and a fast response time was fabricated to demonstrate the capability of this method for the realization of printed electronic devices. PMID:27082455

  19. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful......, in order to encompass dynamic atmospheres as intertwined, constantly shifting negotiations between the rhythms of the environment and of the body. The contribution of this paper is to unravel these negotiations of diverse rhythms, in order to approach dynamic atmospheres from an operational...

  20. 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...

  1. Inline atmospheric pressure metal-organic chemical vapour deposition for thin film CdTe solar cells

    International Nuclear Information System (INIS)

    A detailed study has been undertaken to assess the deposition of CdTe for thin film devices via an inline atmospheric pressure metal-organic chemical vapour deposition (AP-MOCVD) reactor. The precursors for CdTe synthesis were released from a showerhead assembly normal to a transparent conductive oxide (TCO)/glass substrate, previously coated with a CdZnS window layer using a conventional batch AP-MOCVD reactor with horizontal flow delivery. Under a simulated illumination with air mass coefficient 1.5 (AM1.5), the initial best cell conversion efficiency (11.2%) for such hybrid cells was comparable to a reference device efficiency (∼ 13%), grown entirely in the AP-MOCVD batch reactor. The performance and structure of the hybrid and conventional devices are compared for spectral response, CdTe grain morphology and crystal structure. These preliminary results reported on the transfer from a batch to an inline AP-MOCVD reactor which holds a good potential for the large-scale production of thin film photovoltaics devices and related materials. - Highlights: • Inline metal-organic chemical vapour deposition (MOCVD) used to grow CdTe films • Desired dopant profiles in CdTe:As achieved with inline MOCVD reactor • Initial conversion efficiency of 11.2% was comparable to batch devices (∼ 13%). • Inline MOCVD holds a good potential for large-scale thin film photovoltaics production

  2. Atmospheric corrosion Monitoring with Time-of-Wetness (TOW) sensor and Thin Film Electric Resistance (TFER) sensor

    International Nuclear Information System (INIS)

    In this study, TOW sensor was fabricated with the same P. J. Serada's in NRC and was evaluated according to pollutant amount and wet/dry cycle. Laboratorily fabricated thin film electric resistance (TFER) probes were applied in same environment for the measurement of corrosion rate for feasibility. TOW sensor could not differentiate the wet and dry time especially at polluted environment like 3.5% NaCl solution. This implies that wet/dry time monitoring by means of TOW sensor need careful application on various environment. TFER sensor could produce instant atmospheric corrosion rate regardless of environment condition. And corrosion rate obtained by TFER sensor could be differentiated according to wet/dry cycle, wet/dry cycle time variation and solution chemistry. Corrosion behaviors of TFER sensor showed that corrosion could proceed even after wet cycle because of remained electrolyte at the surface

  3. Atmospheric pressure chemical vapour deposition of thermochromic tungsten doped vanadium dioxide thin films for use in architectural glazing

    International Nuclear Information System (INIS)

    Atmospheric pressure chemical vapour deposition of VCl4, WCl6 and water at 550 oC lead to the production of high quality tungsten doped vanadium dioxide thin films. Careful control of the gas phase precursors allowed for tungsten doping up to 8 at.%. The transition temperature of the thermochromic switch was tunable in the range 55 oC to - 23 oC. The films were analysed using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. Their optical properties were examined using variable-temperature transmission and reflectance spectroscopy. It was found that incorporation of tungsten into the films led to an improvement in the colour from yellow/brown to green/blue depending on the level of tungsten incorporation. The films were optimized for optical transmission, thermochromic switching temperature, magnitude of the switching behaviour and colour to produce films that are suitable for use as an energy saving environmental glass product.

  4. Structural and Luminescent Properties of ZnO Thin Films Deposited by Atmospheric Pressure Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guo-Liang; LIN Bi-Xia; HONG Liang; MENG Xiang-Dong; FU Zhu-Xi

    2004-01-01

    ZnO thin films were successfully deposited on Si (100) substrates by chemical vapour deposition (CVD) at atmospheric pressure (1 atm). The only solid source used here is zinc acetate, (CHsCOO)2Zn, and the carrier gas is nitrogen. The sample, which was prepared at 550℃ during growth and then annealed in air at 900℃ , has only a ZnO (002) diffraction peak at 34.6° with its FWHM of 0.23° in the XRD pattern. The room-temperature PL spectrum shows a strong ultraviolet emission with the peak centred at 380nm. We analysed the effects of many factors, such as the source, substrates, growth and annealing temperatures, and annealing ambience, on the structural and optical properties of our prepared ZnO films.

  5. Testing of degreasing copper thin strips and foils in coils by heat treatment in the protective atmosphere

    International Nuclear Information System (INIS)

    Contemporary production of half hard copper thin strips and foils of dry surface, temper F24 /DIN 17660/ consists of: final rolling - degreasing - final slitting. Copper and Brass rolling mill Sevojno does not feature degreasing device after cold rolling process for thickness under 0,2 mm. So, in order to achieve above mentioned temper, tests were made to degrease strips in coils by heat treatment in the protective atmosphere. Analysis of results showed, that after two-stage heating /300 oC,60 min and 330 oC,30 min /,using rolling oil with boiling range oC, strips remain in requested half hard temper with bright surface and residual oil up to 0,32 mg/dm2. (Original)

  6. Conductive zinc oxide thin film coatings by combustion chemical vapour deposition at atmospheric pressure

    International Nuclear Information System (INIS)

    We have established a combustion chemical vapour deposition (C-CVD) system for the deposition of zinc oxide (ZnO) at atmospheric pressure. This C-CVD process has the advantage of a short exposure of the substrates to the flame. It is also potentially applicable as an inline coating system. Fundamental studies were performed on undoped ZnO. The specific resistivity of these layers strongly depends on the film thickness and decreases with increasing thickness. As the lowest resistivities, values of about 2.0 · 10−1 Ωcm are achieved. Ultra-violet photoemission spectra show the valence band structure of the deposited ZnO. The work function and valence band edge were determined. UV–vis spectra were taken to investigate the transmission of the coated glass samples. From these spectra the band gap energy was obtained. Raman spectroscopy as well as infrared spectroscopy confirmed the presence of ordered ZnO crystallites. The X-ray diffraction verified this result and illustrates the hexagonal structure. In the mid-infrared range precursor deposits were detected for low substrate temperatures. - Highlights: ► Zinc oxide (ZnO) films are conductive in the range of 2.0 · 10−1 Ωcm. ► X-ray diffraction, Raman and infrared spectroscopy indicate crystalline ZnO films. ► Precursor deposits were proved within the films for low growing temperatures. ► Band gap energy changes are achieved due to different growing temperatures

  7. Update on Atmospheric Neutrinos

    CERN Document Server

    González-Garciá, M Concepción; Peres, O L G; Stanev, T; Valle, José W F

    1998-01-01

    We discuss the impact of recent experimental results on the determination of atmospheric neutrino oscillation parameters. We use all published results on atmospheric neutrinos, including the preliminary large statistics data of Super-Kamiokande. We re-analyze the data in terms of both $\

  8. Atmosphere and Heritage

    DEFF Research Database (Denmark)

    Ventzel Riis, Nina

    2012-01-01

    -between of the materials. This is what we identify as atmosphere, an enveloping phenomenon that surrounds and affects our sensuous system and well-being when we approach, enter, stay or move in a building. When we leave the building again we carry this atmospheric multi-sensory experience with us without adequate methods...

  9. Urban atmospheric contamination

    International Nuclear Information System (INIS)

    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

  10. Magneto-atmospheric waves

    Science.gov (United States)

    Thomas, J. H.

    1983-01-01

    A theoretical treatment of magneto-atmospheric waves is presented and applied to the modelling of waves in the solar atmosphere. The waves arise in compressible, stratified, electrically conductive atmospheres within gravitational fields when permeated by a magnetic field. Compression, buoyancy, and distortion of the magnetic field all contribute to the existence of the waves. Basic linearized equations are introduced to describe the waves and attention is given to plane-stratified atmospheres and their stability. A dispersion relation is defined for wave propagation in a plane-stratified atmosphere when there are no plane-wave solutions. Solutions are found for the full wave equation in the presence of either a vertical or a horizontal magnetic field. The theory is applied to describing waves in sunspots, in penumbrae, and flare-induced coronal disturbances.

  11. Effects of annealing atmosphere on crystallization and electrical properties in BiFeO3 thin films by chemical solution deposition(CSD)

    International Nuclear Information System (INIS)

    BiFeO3 (BFO) thin films have been prepared on platinized silicon substrates by chemical solution deposition (CSD) and annealed at 600 .deg. C for 1 hour under various atmospheres, i.e., O2, Air and N2. Effects of annealing atmospheres on the crystallization and electrical properties of BFO films were investigated. Crystallization behavior and electrical properties of BFO films depend on the oxygen partial pressure of the annealing atmosphere. The BFO thin film annealed in N2 atmosphere showed a good crystallinity. The surface roughness of the BFO film decreased with lowering oxygen partial pressure of the annealing atmosphere. Low leakage current density and P-E hysteresis were found only in the BFO film annealed at 600 .deg. C under N2 atmosphere. Leakage current density, polarization (at zero electric field) and electric field (at zero polarization) of the BFO film annealed at 600 .deg. C under N2 are 5 x 10-7 A/cm2 at 1 V, 0.2 μC/cm2 and 15kV/cm, respectively

  12. Influence of gas flow dynamics on discharge stability and on the uniformity of atmospheric pressure PECVD thin film

    Energy Technology Data Exchange (ETDEWEB)

    Caquineau, H; Enache, I; Gherardi, N; Naude, N [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Massines, F, E-mail: caquineau@laplace.univ-tlse.f [PROMES-CNRS, Tecnosud, Rambla de la Thermodynamique, F-66100 (France)

    2009-06-21

    The aim of this paper is to improve the understanding of the mechanisms controlling the uniformity of thin films made by atmospheric pressure plasma enhanced chemical vapour deposition (AP-PECVD). To reach this goal, the influence of the gas flow-rate and injection design on the thin film thickness uniformity is studied through experiments and numerical simulation in the case of silica-like layers deposited from silane and nitrous oxide using a nitrogen Townsend dielectric barrier discharge. Results show that whatever the gas flow-rate, when the gas is injected uniformly parallel to the substrate, the obtained layer is always uniform along the substrate width, while when the gas is injected perpendicularly to the substrate, the width-uniformity of the layers decreases when the gas flow-rate increases. The layer non-uniformity is related to the penetration of gas recirculation into the discharge zone, which was confirmed by computational fluid dynamics. This link is corroborated experimentally by a clear improvement of the deposit uniformity when the discharge cell dimensions are modified in order to reduce the recirculation influence on the discharge. A plausible hypothesis for the layer uniformity dependence on the recirculation is the possible enhancement of powder formation and growth in the recirculation zone: when the particle size is large enough, electrons may attach on the powder inducing electron depletion at the origin of the discharge instabilities.

  13. Photocatalytic Functional Coating of TiO2 Thin Film Deposited by Cyclic Plasma Chemical Vapor Deposition at Atmospheric Pressure

    Science.gov (United States)

    Kwon, Jung-Dae; Rha, Jong-Joo; Nam, Kee-Seok; Park, Jin-Seong

    2011-08-01

    Photocatalytic TiO2 thin films were prepared with titanium tetraisopropoxide (TTIP) using cyclic plasma chemical vapor deposition (CPCVD) at atmospheric pressure. The CPCVD TiO2 films contain carbon-free impurities up to 100 °C and polycrystalline anatase phases up to 200 °C, due to the radicals and ion-bombardments. The CPCVD TiO2 films have high transparency in the visible wavelength region and absorb wavelengths below 400 nm (>3.2 eV). The photocatalytic effects of the CPCVD TiO2 and commercial sprayed TiO2 films were measured by decomposing methylene blue (MB) solution under UV irradiation. The smooth CPCVD TiO2 films showed a relatively lower photocatalytic efficiency, but superior catalyst-recycling efficiency, due to their high adhesion strength on the substrates. This CPCVD technique may provide the means to produce photocatalytic thin films with low cost and high efficiency, which would be a reasonable candidate for practical photocatalytic applications, because of the reliability and stability of their photocatalytic efficiency in a practical environment.

  14. Modelling of plasma generation and thin film deposition by a non-thermal plasma jet at atmospheric pressure

    Science.gov (United States)

    Sigeneger, F.; Becker, M. M.; Foest, R.; Loffhagen, D.

    2016-09-01

    The gas flow and plasma in a miniaturized non-thermal atmospheric pressure plasma jet for plasma enhanced chemical vapour deposition has been investigated by means of hydrodynamic modelling. The investigation focuses on the interplay between the plasma generation in the active zone where the power is supplied by an rf voltage to the filaments, the transport of active plasma particles due to the gas flow into the effluent, their reactions with the thin film precursor molecules and the transport of precursor fragments towards the substrate. The main features of the spatially two-dimensional model used are given. The results of the numerical modelling show that most active particles of the argon plasma are mainly confined within the active volume in the outer capillary of the plasma jet, with the exception of molecular argon ions which are transported remarkably into the effluent together with slow electrons. A simplified model of the precursor kinetics yields radial profiles of precursor fragment fluxes onto the substrate, which agree qualitatively with the measured profiles of thin films obtained by static film deposition experiments.

  15. Atmosphere influence on in situ ion beam analysis of thin film growth

    International Nuclear Information System (INIS)

    In situ, nondestructive surface characterization of thin-film growth processes in an environment of chemically active gas at pressures of several mTorr is required both for the understanding of growth processes in multicomponent films and layered heterostructures and for the improvement of process reproducibility and device reliability. The authors have developed a differentially pumped pulsed ion beam surface analysis system that includes ion scattering spectroscopy (ISS) and direct recoil spectroscopy (DRS), coupled to an automated ion beam sputter-deposition system (IBSD), to study film growth processes in an environment of chemically active gas, such as required for the growth of oxide, nitride, or diamond thin films. The influence of gas-phase scattering and gas-surface interactions on the ISS and DRS signal intensity and peak shape have been studied. From the intensity variation as a function of ambient gas pressure, the authors have calculated the mean free path and the scattering cross-section for a given combination of primary ion species and ambient gas. Depending on the system geometry and the combination of primary beam and background, it is shown that surface-specific data can be obtained during thin-film growth at pressures ranging from a few mtorr to approximately 1 Torr. Detailed information such as surface composition, structure, and film growth mechanism may be obtained in real-time, making ion beam analysis an ideal nondestructive, in situ probe of thin-film growth processes

  16. 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).

  17. An archetype hydrogen atmosphere problem

    International Nuclear Information System (INIS)

    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.)

  18. 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.

  19. Positioning of the Precursor Gas Inlet in an Atmospheric Dielectric Barrier Reactor, and its Effect on the Quality of Deposited TiOx Thin Film Surface

    Directory of Open Access Journals (Sweden)

    Jan Píchal

    2013-01-01

    Full Text Available Thin film technology has become pervasive in many applications in recent years, but it remains difficult to select the best deposition technique. A further consideration is that, due to ecological demands, we are forced to search for environmentally benign methods. One such method might be the application of cold plasmas, and there has already been a rapid growth in studies of cold plasma techniques. Plasma technologies operating at atmospheric pressure have been attracting increasing attention. The easiest way to obtain low temperature plasma at atmospheric pressure seems to be through atmospheric dielectric barrier discharge (ADBD. We used the plasma enhanced chemical vapour deposition (PECVD method applying atmospheric dielectric barrier discharge (ADBD plasmafor TiOx thin films deposition, employing titanium isopropoxide (TTIP and oxygen as reactants, and argon as a working gas. ADBD was operated in filamentary mode. The films were deposited on glass. We studied the quality of the deposited TiOx thin film surface for various precursor gas inlet positions in the ADBD reactor. The best thin films quality was achieved when the precursor gases were brought close to the substrate surface directly through the inlet placed in one of the electrodes.High hydrophilicity of the samples was proved by contact angle tests (CA. The film morphology was tested by atomic force microscopy (AFM. The thickness of the thin films varied in the range of (80 ÷ 210 nm in dependence on the composition of the reactor atmosphere. XPS analyses indicate that composition of the films is more like the composition of TiOxCy.

  20. Atmospheric Neutrino Status

    CERN Document Server

    O'Sullivan, E

    2016-01-01

    This conference proceeding discusses new results arising from atmospheric neutrino detection in the Super-Kamiokande and IceCube experiments. Super-Kamiokande has measured atmospheric neutrinos in the energy range of 100 MeV-10 TeV and uses this data set to conclusively measure the east-west effect to 8.0 (6.0) $\\sigma$ for electron (muon) neutrinos. IceCube is ideal for measuring high energy atmospheric neutrinos and has explored how different production channels for atmospheric neutrinos contribute to the total overall observed flux. The measurement is consistent with the conventional spectrum, produced by the decay of pions and kaon, while the contribution from the prompt channel (due to charm decay) is consistent with zero.

  1. Unravelling our atmosphere

    Science.gov (United States)

    Caldwell, Martin

    2014-05-01

    A main limiting factor in climate predictions is that we do not understand atmospheric processes as a function of height. An upcoming European and Japanese space mission called EarthCARE seeks to remedy this, as Martin Caldwell explains.

  2. Heterogeneous atmospheric chemistry

    Science.gov (United States)

    Schryer, D. R.

    1982-01-01

    The present conference on heterogeneous atmospheric chemistry considers such topics concerning clusters, particles and microparticles as common problems in nucleation and growth, chemical kinetics, and catalysis, chemical reactions with aerosols, electron beam studies of natural and anthropogenic microparticles, and structural studies employing molecular beam techniques, as well as such gas-solid interaction topics as photoassisted reactions, catalyzed photolysis, and heterogeneous catalysis. Also discussed are sulfur dioxide absorption, oxidation, and oxidation inhibition in falling drops, sulfur dioxide/water equilibria, the evidence for heterogeneous catalysis in the atmosphere, the importance of heterogeneous processes to tropospheric chemistry, soot-catalyzed atmospheric reactions, and the concentrations and mechanisms of formation of sulfate in the atmospheric boundary layer.

  3. The origin of atmosphere

    International Nuclear Information System (INIS)

    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.)

  4. The invention of atmosphere.

    Science.gov (United States)

    Martin, Craig

    2015-08-01

    The word "atmosphere" was a neologism Willebrord Snellius created for his Latin translation of Simon Stevin's cosmographical writings. Astronomers and mathematical practitioners, such as Snellius and Christoph Scheiner, applying the techniques of Ibn Mu'ādh and Witelo, were the first to use the term in their calculations of the height of vapors that cause twilight. Their understandings of the atmosphere diverged from Aristotelian divisions of the aerial region. From the early years of the seventeenth century, the term was often associated with atomism or corpuscular matter theory. The concept of the atmosphere changed dramatically with the advent of pneumatic experiments in the middle of the seventeenth century. Pierre Gassendi, Walter Charleton, and Robert Boyle transformed the atmosphere of the mathematicians giving it the characteristics of weight, specific gravity, and fluidity, while disputes about its extent and border remained unresolved. PMID:26193787

  5. 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)

  6. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE 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.

  7. Middle atmospheric electrodynamics

    Science.gov (United States)

    Kelley, M. C.

    1983-01-01

    A review is presented of the advances made during the last few years with respect to the study of the electrodynamics in the earth's middle atmosphere. In a report of the experimental work conducted, attention is given to large middle atmospheric electric fields, the downward coupling of high altitude processes into the middle atmosphere, and upward coupling of tropospheric processes into the middle atmosphere. It is pointed out that new developments in tethered balloons and superpressure balloons should greatly increase the measurement duration of earth-ionospheric potential measurements and of stratospheric electric field measurements in the next few years. Theoretical work considered provides an excellent starting point for study of upward coupling of transient and dc electric fields. Hays and Roble (1979) were the first to construct a model which included orographic features as well as the classical thunderstorm generator.

  8. 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....

  9. Atmospheric release advisory capability

    International Nuclear Information System (INIS)

    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. 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...

  11. Atmospheric muons: experimental aspects

    CERN Document Server

    Cecchini, Stefano

    2012-01-01

    We present a review of atmospheric muon flux and energy spectrum measurements over almost six decades of muon momentum. Sea-level and underground/water/ice experiments are considered. Possible sources of systematic errors in the measurements are examinated. The characteristics of underground/water muons (muons in bundle, lateral distribution, energy spectrum) are discussed. The connection between the atmospheric muon and neutrino measurements are also reported.

  12. Annealing of polycrystalline thin film silicon solar cells in water vapour at sub-atmospheric pressures

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Píč, Vlastimil; Benda, V.; Fejfar, Antonín

    2014-01-01

    Roč. 54, č. 5 (2014), s. 341-347. ISSN 1210-2709 R&D Projects: GA MŠk 7E10061 EU Projects: European Commission(XE) 240826 - PolySiMode Grant ostatní: AVČR(CZ) M100101216 Institutional support: RVO:68378271 Keywords : passivation * water vapour * thin film solar cell * polycrystalline silicon (poly-Si) * multicrys- talline silicon (m-Si) * Suns-VOC Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use

  13. Dynamics in Atmospheric Physics

    Science.gov (United States)

    Lindzen, Richard A.

    2005-08-01

    Motion is manifest in the atmosphere in an almost infinite variety of ways. In Dynamics in Atmospheric Physics, Dr. Richard Lindzen describes the nature of motion in the atmosphere, develops fluid dynamics relevant to the atmosphere, and explores the role of motion in determining the climate and atmospheric composition. The author presents the material in a lecture note style, and the emphasis throughout is on describing phenomena that are at the frontiers of current research, but due attention is given to the methodology of research and to the historical background of these topics. The author's treatment and choice of topics is didactic. Problems at the end of each chapter will help students assimilate the material. In general the discussions emphasize physical concepts, and throughout Dr. Lindzen makes a concerted effort to avoid the notion that dynamic meteorology is simply the derivation of equations and their subsequent solution. His desire is that interested students will delve further into solution details. The book is intended as a text for first year graduate students in the atmospheric sciences. Although the material in the book is self contained, a familiarity with differential equations is assumed; some background in fluid mechanics is helpful.

  14. GREAT/SOFIA atmospheric calibration

    OpenAIRE

    Guan, Xin; Stutzki, Jürgen; Graf, Urs U.; Güsten, Rolf; Okada, Yoko; Torres, Miguel Angel Requena; Simon, Robert; Wiesemeyer, Helmut

    2012-01-01

    The GREAT observations need frequency-selective calibration across the passband for the residual atmospheric opacity at flight altitude. At these altitudes the atmospheric opacity has both narrow and broad spectral features. To determine the atmospheric transmission at high spectral resolution, GREAT compares the observed atmospheric emission with atmospheric model predictions, and therefore depends on the validity of the atmospheric models. We discusse the problems identified in this compari...

  15. An Analytical Approach to Scattering Between Two Thin Magnetic Flux Tubes in a Stratified Atmosphere

    CERN Document Server

    Hanson, Chris S

    2014-01-01

    We expand on recent studies to analytically model the behavior of two thin flux tubes interacting through the near- and acoustic far-field. The multiple scattering that occurs between the pair alters the absorption and phase of the outgoing wave, when compared to non-interacting tubes. We have included both the sausage and kink scatter produced by the pair. It is shown that the sausage mode's contribution to the scattered wave field is significant, and plays an equally important role in the multiple scattering regime. A disparity between recent numerical results and analytical studies, in particular the lack of symmetry between the two kink modes, is addressed. This symmetry break is found to be caused by an incorrect solution for the near-field modes.

  16. Atmospheric pressure chemical vapour deposition of thermochromic tungsten doped vanadium dioxide thin films for use in architectural glazing

    Energy Technology Data Exchange (ETDEWEB)

    Blackman, Christopher S., E-mail: c.blackman@ucl.ac.u [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Piccirillo, C.; Binions, R.; Parkin, Ivan P. [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom)

    2009-06-30

    Atmospheric pressure chemical vapour deposition of VCl{sub 4}, WCl{sub 6} and water at 550 {sup o}C lead to the production of high quality tungsten doped vanadium dioxide thin films. Careful control of the gas phase precursors allowed for tungsten doping up to 8 at.%. The transition temperature of the thermochromic switch was tunable in the range 55 {sup o}C to - 23 {sup o}C. The films were analysed using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. Their optical properties were examined using variable-temperature transmission and reflectance spectroscopy. It was found that incorporation of tungsten into the films led to an improvement in the colour from yellow/brown to green/blue depending on the level of tungsten incorporation. The films were optimized for optical transmission, thermochromic switching temperature, magnitude of the switching behaviour and colour to produce films that are suitable for use as an energy saving environmental glass product.

  17. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography.

    Science.gov (United States)

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2016-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1 W, was used. The combination of the simple, low-budget laser pointer and the FAPA ion source has made this experimental arrangement broadly available, also for small laboratories. The approach was successfully applied for the characterization of low molecular weight compounds separated on TLC plates, such as a mixture of pyrazole derivatives, alkaloids (nicotine and sparteine), and an extract from a drug tablet consisting of paracetamol, propyphenazone, and caffeine. The laser pointer used was capable of ablating organic compounds without the need of application of any additional substances (matrices, staining, etc.) on the TLC spots. The detection limit of the proposed method was estimated to be 35 ng/cm(2) of a pyrazole derivative. PMID:26563110

  18. Deposition of Polymer Thin Film Using an Atmospheric Pressure Micro-Plasma Driven by Dual-Frequency Excitation

    International Nuclear Information System (INIS)

    Polymer thin film deposition using an atmospheric pressure micro-plasma jet driven by dual-frequency excitations is described in this paper. The discharge process was operated with a mixture of argon (6 slm) and a small amount of acetone (0-2100 ppm). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar spectra lines, we observed some spectra of C, CN, CH and C2. Through changing acetone content mixed in argon, we found that the optimum discharge condition for deposition can be characterized by the maximum concentration of carbonaceous species. The deposited film was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The XPS indicated that the film was mostly composed of C with trace amount of O and N elements. The FTIR suggested different carbon-containing bonds (−CHx, C=O, C=C, C-O-C) presented in the deposited film. (plasma technology)

  19. Fabrication of a Transparent Anti-stain Thin Film Using an Atmospheric Pressure Cold Plasma Deposition System

    Directory of Open Access Journals (Sweden)

    Suzaki Y.

    2013-08-01

    Full Text Available Recently, outdoor-constructed solar panels have a problem such as power generation efficiency is reduced by the face plate dirt. On the other hand, electronic touch panels have a problem such as deterioration of visibility of the screen by finger grease stain. To solve these problems, we need to fabricate the anti-stain surfaces which have superhydrophobic and oil-repellent abilities without spoiling the transparency of the transparent substrate. In this study, we fabricated lotus leaves like surface on a glass substrate. Firstly, SiO2 particles of ca. 100 nm diameter were arranged on the glass substrates. Secondly, to obtain the fractal-like structure (ultra-micro-rough structure on the surface, ZnO thin film having a columnar structure was fabricated on the SiO2 particles by using an atmospheric pressure cold plasma deposition system. By using these processes, the ZnO columns formed radiantly on the spherical surface of the SiO2 particles. Furthermore, without spoiling the ultra-micro-rough structure, a transparent anti-stain monolayer with low surface energy was prepared by using a chemical adsorption technique onto the surface. Average value of the water droplet contact angles of the samples fabricated was 151.8 deg. Field emission scanning electron microscope (FE-SEM observation reviled that this sample has a raspberry structure in which columnar structure has grown radially on the SiO2 particles.

  20. Preparation of nitrogen doped silicon oxides thin films by plasma polymerization of 3-aminopropyltriethoxylsilane using atmospheric pressure plasma jet

    Science.gov (United States)

    Lin, Yu-Chun; Wang, Meng-Jiy

    2016-01-01

    Surface modification techniques have been applied in various applications including self-cleaning surface, antibacterial filter, and biomaterials. In this study we employed the atmospheric pressure plasma jet (APPJ) deposition, a dry process for surface modification, to deposit 3-aminopropyltriethoxylsilane (APTES) on stainless steel (SS) on the purposes of simultaneously incorporating SiOx and nitrogen containing functionalities for the modulation of biofunctionality. The APPJ deposition allowed to form a thin layer of APTES with linear growth rate by controlling the deposition time. In addition, the surface chemical and physical properties, such as surface chemical composition, wettability, film thickness, and interactions with mammalian cells were evaluated by using different analytical methods. The results showed that the surface wettability was improved significantly due to the APTES deposition along with the increase of the incorporated nitrogen content. Moreover, the viability of L-929 fibroblasts was clearly promoted on the APTES deposited SS, which is most probably due to the thicker deposited films and higher density of nitrogen-containing functional groups. The outcomes of this research showed great potential to apply on metallic substrates in real time for biomedical related applications.

  1. Deposition of Polymer Thin Film Using an Atmospheric Pressure Micro-Plasma Driven by Dual-Frequency Excitation

    Science.gov (United States)

    Wang, Xiaomin; Yuan, Qianghua; Zhou, Yongjie; Yin, Guiqin; Dong, Chenzhong

    2014-01-01

    Polymer thin film deposition using an atmospheric pressure micro-plasma jet driven by dual-frequency excitations is described in this paper. The discharge process was operated with a mixture of argon (6 slm) and a small amount of acetone (0-2100 ppm). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar spectra lines, we observed some spectra of C, CN, CH and C2. Through changing acetone content mixed in argon, we found that the optimum discharge condition for deposition can be characterized by the maximum concentration of carbonaceous species. The deposited film was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The XPS indicated that the film was mostly composed of C with trace amount of O and N elements. The FTIR suggested different carbon-containing bonds (-CHx, C=O, C=C, C-O-C) presented in the deposited film.

  2. Fine Pattern Etching of Molybdenum Thin Film and Silicon Substrate by Using Atmospheric Line-Shaped Microplasma Source

    Science.gov (United States)

    Okumura, Tomohiro; Saitoh, Mitsuo; Yashiro, Yoichiro; Kimura, Tadashi

    2003-06-01

    An atmospheric line-shaped microplasma source was developed for fine pattern etching. Observation of plasma emission of the developed plasma source has revealed that the finest plasma line is formed when helium (He) gas is supplied to the inner gas feed and reaction gas to the outer gas feeds. When reaction gas is supplied to the outer gas feeds, fluorine radical (F*) emission intensity increases with the gas flow rate, eventually exceeding the maximum emission intensity obtained when a mixture of reaction gas and He gas is supplied to the inner gas feed. Fine pattern etching of molybdenum thin film and silicon substrate was experimentally carried out using microplasma sources in two different configurations: one with the copper electrode covered to protect it from plasma exposure (type 1), and the other with the aluminum electrode end knife-edged and exposed to a plasma (type 2). The experiment revealed that the type 2 source provides a higher etching rate than of the type 1 source. The type 2 source can produce a fine etched pattern with lines of several ten to several hundred μm width. The maximum etching rate of silicon substrate is 79.0 μm/min.

  3. Observations of Exoplanet Atmospheres

    CERN Document Server

    Crossfield, Ian J M

    2015-01-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  4. 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...

  5. Phenomenology of atmospheric neutrinos

    Science.gov (United States)

    Fedynitch, Anatoli

    2016-04-01

    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.

  6. Atmospheric Radiative Transfer

    Science.gov (United States)

    Perliski, Lori

    Because radiative transfer cuts across many scientific disciplines with applications including remote sensing, climate, atmospheric chemistry, and photobiology, there is a need for comprehensive books on this subject that can appeal to a wide readership. While Atmospheric Radiative Transfer takes strides toward filling this niche by addressing a broad range of topics, it is dry reading and suffers from lack of detail. The book was based on a graduate-level course taught at the University of Sciences and Technologies in Lille, France, and indeed, the text reads much like an expanded outline perhaps derived from lecture notes.Part one deals with general radiative transfer, and part two covers Earth's radiation budget, the climate system, and remote sensing techniques. The radiative transfer equation and solutions for absorbing and scattering atmospheres are discussed as are the details of absorption, such as energy levels, line strengths, line intensities, equivalent widths, and weak- and strong-line limits.

  7. Observations of Exoplanet Atmospheres

    Science.gov (United States)

    Crossfield, Ian J. M.

    2015-10-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics and circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress, while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  8. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  9. 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.

  10. Photochemistry of Pluto's Atmosphere

    Science.gov (United States)

    Krasnopolsky, Vladimir A.

    1999-01-01

    This work include studies of two problems: (1) Modeling thermal balance, structure. and escape processes in Pluto's upper atmosphere. This study has been completed in full. A new method, of analytic solution for the equation of hydrodynamic flow from in atmosphere been developed. It was found that the ultraviolet absorption by methane which was previously ignored is even more important in Pluto's thermal balance than the extreme ultraviolet absorption by nitrogen. Two basic models of the lower atmosphere have been suggested, with a tropopause and a planetary surface at the bottom of the stellar occultation lightcurve, respectively, Vertical profiles, of temperature, density, gas velocity, and the CH4 mixing ratio have been calculated for these two models at low, mean, and high solar activity (six models). We prove that Pluto' " s atmosphere is restricted to 3060-4500 km, which makes possible a close flyby of future spacecraft. Implication for Pluto's evolution have also been discussed. and (2) Modeling of Pluto's photochemistry. Based on the results of (1), we have made some changes in the basic continuity equation and in the boundary conditions which reflect a unique can of hydrodynamic escape and therefore have not been used in modeling of other planetary atmospheres. We model photochemistry of 44 neutral and 23 ion species. This work required solution of a set of 67 second-order nonlinear ordinary differential equations. Two models have been developed. Each model consists of the vertical profiles for 67 species, their escape and precipitation rates. These models predict the chemical structure and basic chemical processes in the current atmosphere and possible implication of these processes for evolution. This study has also been completed in full.

  11. Composition of Estonian atmosphere

    International Nuclear Information System (INIS)

    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 SO2 and NOx 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, CO2, 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

  12. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    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

  13. 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 introdu

  14. [Spectral analyzing effects of atmosphere states on the structure and characteristics of CdTe polycrystalline thin films made by close-spaced sublimation].

    Science.gov (United States)

    Zheng, Hua-jing; Zheng, Jia-gui; Feng, Liang-huan; Zhang, Jing-quan; Xie, Er-qing

    2005-07-01

    The structure and characteristics of CdTe thin films are dependent on the working atmosphere states in close-spaced sublimation. In the present paper, CdTe polycrystalline thin films were deposited by CSS in mixture atmosphere of argon and oxygen. The physical mechanism of CSS was analyzed, and the temperature distribution in CSS system was measured. The dependence of preliminary nucleus creation on the atmosphere states (involving component and pressure) was studied. Transparencies were measured and optic energy gaps were calculated. The results show that: (1) The CdTe films deposited in different atmospheres are cubic structure. With increasing oxygen concentration, a increases and reaches the maximum at 6% oxygen concentration, then reduces, and increases again after passing the point at 12% oxygen concentration. Among them, the sample depositing at 9% oxygen concentration is the best. The optic energy gaps are 1.50-1.51 eV for all CdTe films. (2) The samples depositing at different pressures at 9% oxygen concentration are all cubical structure of CdTe, and the diffraction peaks of CdS and SnO2:F still appear. With the gas pressure increasing, the crystal size of CdTe minishes, the transparency of the thin film goes down, and the absorption side shifts to the short-wave direction. (3) The polycrystalline thin films with high quality deposit in 4 minutes under the depositing condition that the substrate temperature is 550 degrees C, and source temperature is 620 degrees C at 9% oxygen concentration. PMID:16241058

  15. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

    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.

  16. Solar Atmosphere Models

    Science.gov (United States)

    Rutten, R. J.

    2002-12-01

    This contribution honoring Kees de Jager's 80th birthday is a review of "one-dimensional" solar atmosphere modeling that followed on the initial "Utrecht Reference Photosphere" of Heintze, Hubenet & de Jager (1964). My starting point is the Bilderberg conference, convened by de Jager in 1967 at the time when NLTE radiative transfer theory became mature. The resulting Bilderberg model was quickly superseded by the HSRA and later by the VAL-FAL sequence of increasingly sophisticated NLTE continuum-fitting models from Harvard. They became the "standard models" of solar atmosphere physics, but Holweger's relatively simple LTE line-fitting model still persists as a favorite of solar abundance determiners. After a brief model inventory I discuss subsequent work on the major modeling issues (coherency, NLTE, dynamics) listed as to-do items by de Jager in 1968. The present conclusion is that one-dimensional modeling recovers Schwarzschild's (1906) finding that the lower solar atmosphere is grosso modo in radiative equilibrium. This is a boon for applications regarding the solar atmosphere as one-dimensional stellar example - but the real sun, including all the intricate phenomena that now constitute the mainstay of solar physics, is vastly more interesting.

  17. Climate and atmospheric research

    International Nuclear Information System (INIS)

    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)

  18. 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.

  19. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

    J G Learned

    2000-07-01

    With the announcement of new evidence for muon neutrino disappearance observed by the super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an apparently inescapable fact. The evidence is reviewed, and new indications are presented that the oscillations are probably between muon and tau neutrinos. Implications and future directions are discussed.

  20. Vehicle Cabin Atmosphere Monitor

    Science.gov (United States)

    Chutjian, Ara; Darrach, Muray

    2007-01-01

    Vehicle Cabin Atmosphere Monitor (VCAM) identifies gases that are present in minute quantities in the International Space Station (ISS) breathing air that could harm the crew s health. If successful, instruments like VCAM could accompany crewmembers during long-duration exploration missions to the Moon or traveling to Mars.

  1. 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...

  2. Electrochemical Measurement of Atmospheric Corrosion

    Science.gov (United States)

    DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

    1999-01-01

    Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

  3. Validation of the Atmospheric Infrared Sounder (AIRS) over the Antarctic Plateau: Low Radiance, Low Humidity, and Thin Clouds

    Science.gov (United States)

    Tobin, David C.

    2005-01-01

    The main goal of the project has been to use specialized measurements collected at the Antarctic Plateau to provide validation of the Atmospheric InfraRed Sounder (AIRS) spectral radiances and some AIRS Level 2 products. As proposed, efforts conducted at the University of Wisconsin are focused on providing technical information, data, and software in support of the validation studies.

  4. Dreaming of atmospheres

    CERN Document Server

    Waldmann, I P

    2015-01-01

    Here we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrievals 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 recognise molecular signatures for a wide range of planets, atmospheric thermal profiles and compositions. Reconstructions of the learned features, also referred to as `dreams' of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work towards retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from curre...

  5. Atmospheric Release Advisory Capability

    International Nuclear Information System (INIS)

    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

  6. Atmospheric lepton fluxes

    Directory of Open Access Journals (Sweden)

    Gaisser Thomas K.

    2015-01-01

    Full Text Available This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric νμ and νe are discussed, along with the implications of the muon charge ratio for the νµ / ν̅µ ratio. Methods to account for effects of the knee in the primary cosmic-ray spectrum and the energy-dependence of hadronic interactions on the neutrino fluxes are discussed and illustrated in the context of recent results from IceCube. A simple numerical/analytic method is proposed for systematic investigation of uncertainties in neutrino fluxes arising from uncertainties in the primary cosmic-ray spectrum/composition and hadronic interactions.

  7. Understanding Atmospheric Catastrophes

    Science.gov (United States)

    Chao, Winston C.

    2009-01-01

    The atmosphere, as in other parts of nature, is full of phenomena that involve rapid transitions from one (quasi-) equilibrium state to another--- i.e. catastrophes. These (quasi-) equilibria are the multiple solutions of the same dynamical system. Unlocking the mystery behind a catastrophe reveals not only the physical mechanism responsible for the transition, but also how the (quasi-) equilibria before and after the transition are maintained. Each catastrophe is different, but they do have some common traits. Understanding these common traits is the first step in studying these catastrophes. In this seminar, three examples chosen based on the speaker's research interest--tropical cyclogenesis, stratospheric sudden warming, and monsoon onset--are given to illustrate how atmospheric catastrophes can be studied.

  8. 24. Atmosphere and climate

    International Nuclear Information System (INIS)

    The Earth's atmosphere is changing, and we do not fully understand what the effect of those changes will be on our own lives, much less the lives of our children. It is easy to imagine effects that could be catastrophic for life on this planet. Yet, in the face of these possibilities and our inadequate understanding of Earth processes, anthropogenic emissions of trace gases - pollutants that affect climate, the ozone layer, and human health - continue. Tables give information on the following: CO2 emissions from industrial processes, 1989; Other greenhouse gas emissions, 1989; Atmospheric concentrations of greenhouse and ozone-depleting gases, 1959-90; World CO2 emissions from fossil fuel consumption and cement manufacture, 1950-89; Sulfur and nitrogen emissions, 1970-89; and Common anthropogenic pollutants, 1980-89

  9. Tritium in atmospheric hydrogen

    OpenAIRE

    Martin, J. David; Hackett, Joseph P.

    2011-01-01

    The radioactivity of tritiated hydrogen (HT) in the atmosphere in Westwood, New Jersey was measured at approximately weekly intervals from August 1971 to August 1973. The background level remained constant at approximately 80 tritium atoms per milligram of air. Frequent increases in the activity level of up to an order of magnitude were observed until January 1973. The source(s) of HT which was responsible for the frequent increases apparently ceased as a tropospheric source in January 1973. ...

  10. Atmospheric Disturbance Environment Definition

    Science.gov (United States)

    Tank, William G.

    1994-01-01

    Traditionally, the application of atmospheric disturbance data to airplane design problems has been the domain of the structures engineer. The primary concern in this case is the design of structural components sufficient to handle transient loads induced by the most severe atmospheric "gusts" that might be encountered. The concern has resulted in a considerable body of high altitude gust acceleration data obtained with VGH recorders (airplane velocity, V, vertical acceleration, G, altitude, H) on high-flying airplanes like the U-2 (Ehernberger and Love, 1975). However, the propulsion system designer is less concerned with the accelerations of the airplane than he is with the airflow entering the system's inlet. When the airplane encounters atmospheric turbulence it responds with transient fluctuations in pitch, yaw, and roll angles. These transients, together with fluctuations in the free-stream temperature and pressure will disrupt the total pressure, temperature, Mach number and angularity of the inlet flow. For the mixed compression inlet, the result is a disturbed throat Mach number and/or shock position, and in extreme cases an inlet unstart can occur (cf. Section 2.1). Interest in the effects of inlet unstart on the vehicle dynamics of large, supersonic airplanes is not new. Results published by NASA in 1962 of wind tunnel studies of the problem were used in support of the United States Supersonic Transport program (SST) (White, at aI, 1963). Such studies continued into the late 1970's. However, in spite of such interest, there never was developed an atmospheric disturbance database for inlet unstart analysis to compare with that available for the structures load analysis. Missing were data for the free-stream temperature and pressure disturbances that also contribute to the unStart problem.

  11. 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.

  12. Atmospheric pseudohalogen chemistry

    Directory of Open Access Journals (Sweden)

    D. J. Lary

    2004-09-01

    Full Text Available There are at least three reasons why hydrogen cyanide is likely to be significant for atmospheric chemistry. The first is well known, HCN is a product and marker of biomass burning. However, if a detailed ion chemistry of lightning is considered then it is almost certain than in addition to lightning producing NOx, it also produces HOx and HCN. Unlike NOx and HOx, HCN is long-lived and could therefore be a useful marker of lightning activity. Observational evidence is considered to support this view. Thirdly, the chemical decomposition of HCN leads to the production of small amounts of CN and NCO. NCO can be photolyzed in the visible portion of the spectrum yielding N atoms. The production of N atoms is significant as it leads to the titration of nitrogen from the atmosphere via N+N→N2. Normally the only modelled source of N atoms is NO photolysis which happens largely in the UV Schumann-Runge bands. However, NCO photolysis occurs in the visible and so could be involved in titration of atmospheric nitrogen in the lower stratosphere and troposphere. HCN emission inventories are worthy of attention. The CN and NCO radicals have been termed pseudohalogens since the 1920s. They are strongly bound, univalent, radicals with an extensive and varied chemistry. The products of the atmospheric oxidation of HCN are NO, CO and O3. N+CH4 and N+CH3OH are found to be important sources of HCN. Including the pseudohalogen chemistry gives a small increase in ozone and total reactive nitrogen (NOy.

  13. 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.

  14. Titan's surface and atmosphere

    Science.gov (United States)

    Hayes, Alexander G.; Soderblom, Jason M.; Ádámkovics, Máté

    2016-05-01

    Since its arrival in late 2004, the NASA/ESA Cassini-Huygens mission to Saturn has revealed Titan to be a world that is both strange and familiar. Titan is the only extraterrestrial body known to support standing bodies of stable liquid on its surface and, along with Earth and early Mars, is one of three places in the Solar System known to have had an active hydrologic cycle. With atmospheric pressures of 1.5 bar and temperatures of 90-95 K at the surface, methane and ethane condense out of Titan's nitrogen-dominated atmosphere and flow as liquids on the surface. Despite vast differences in environmental conditions and materials from Earth, Titan's methane-based hydrologic cycle drives climatic and geologic processes which generate landforms that are strikingly similar to their terrestrial counterparts, including vast equatorial dunes, well-organized channel networks that route material through erosional and depositional landscapes, and lakes and seas of liquid hydrocarbons. These similarities make Titan a natural laboratory for studying the processes that shape terrestrial landscapes and drive climates, probing extreme conditions impossible to recreate in earthbound laboratories. Titan's exotic environment ensures that even rudimentary measurements of atmospheric/surface interactions, such as wind-wave generation or aeolian dune development, provide valuable data to anchor physical models.

  15. NOAA's Tropical Atmosphere Ocean Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Realtime El Nino and La Nina data from the tropical Pacific Ocean is provided by the Tropical Atmosphere Ocean / Triangle Trans-Ocean buoy network (TAO/TRITON) of...

  16. Iron Thin Films from Fe„CO…5 and FeCp2/H2O under Atmospheric Pressure

    OpenAIRE

    Senocq, François; Duminica, Florin-Daniel; Maury, Francis; Delsol, Thomas; Vahlas, Constantin

    2006-01-01

    Iron layers were first obtained from iron pentacarbonyl in metallorganic chemical vapor deposition MOCVD process under atmospheric pressure, in the temperature range 473–773 K, in a vertical cold wall reactor. Films of good purity were obtained with or without hydrogen as co-reactant, no chemical additives being used. The experiments showed that the velocity of the gas stream and, to a lower extent, the precursor molar fraction are the key parameters to be controlled, in order to monitor f...

  17. Pluto's Atmosphere Does Not Collapse

    OpenAIRE

    Olkin, C. B.; Young, L. A.; Borncamp, D.; Pickles, A; Sicardy, B.; Assafin, M.; Bianco, F. B.; Buie, M. W.; Oliveira, A. Dias de; Gillon, M.; French, R. G.; Gomes Jr., A. Ramos; Jehin, E.; Morales, N.; Opitom, C.

    2013-01-01

    Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto's atmosphere does not collapse at any point in its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole.

  18. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, Manuel; Fuente, Daniel de la; Díaz Ocaña, Iván; Cano, Heidis

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morpholog...

  19. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, M.; de la Fuente, D.; I. Díaz; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel c...

  20. KAJIAN PUSTAKA MENGENAI RESTAURANT ATMOSPHERE

    OpenAIRE

    Adeline Agoes; Nami Fitricia Pasaribu

    2015-01-01

    Restaurant is one of the businesses that support tourism development. Restaurants nowadays dont only provide food, but also the service and atmosphere to their customers. The purpose of this study is to discover the aspects 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...

  1. Atmospheric corrosion of mild steel. Pt. II. Marine atmospheres

    International Nuclear Information System (INIS)

    This paper summarizes the results obtained in the MICAT project for mild steel specimens exposed for 1 to 4 years in 47 marine atmospheres in the Ibero-American region. All these atmospheres were characterized for climatology, pollution and corrosion rates according to ISO standards. Complementary morphological and chemical characterization of the steel corrosion product layers (SCPLs) formed in these atmospheres was carried out. The overall analysis of results contributes to understanding, in a systematic way, how atmospheric corrosivity categories can be correlated with corrosion mechanisms. Special aspects of the atmospheres, from pure to mixed marine, were considered. (orig.)

  2. Influence of aging atmosphere on the superelastic behavior of Ni50.9-Ti shape memory thin wires

    International Nuclear Information System (INIS)

    Research highlights: → Atmosphere of aging at 450 deg. C has a great effect on superelasticity of NiTi wires. → Oxide layers are not main reason for different superelastic behavior of NiTi wires. → Compositional changes due to oxidation have a significant effect on superelasticity. → Non-homogenous composition changes the sequence and temperature of transformations. - Abstract: Superelastic properties of Ni50.9-Ti shape memory wires were studied after aging in argon and air atmospheres. The oxide surface layer was characterized using transmission electron microscopy. Tensile tests carried out at 50 deg. C up to 5.5% strain to examine superelastic response of samples. In order to determine transformation temperatures differential scanning calorimeter tests were performed. Results indicate that atmosphere of heat treatment affects the transformation temperatures and superelastic behavior significantly. Titanium oxide and Ti2Ni/Ti4Ni2O layers are formed, respectively, on the surface of samples which were aged in air. However, the oxide surface layer is not the main reason for significant difference between superelastic behavior of the samples aged in air and argon. The effect of compositional changes during aging induced by preferential oxidation of titanium on superelastic behavior and transformation temperatures is more significant than oxide layers formed on the surface of wires.

  3. Effects of flow rate of atmosphere gases on the characteristics of Zn-doped ITO (ZITO) thin films for organic light emitting diodes

    Science.gov (United States)

    Jeong, Hwa-Kyun; Lee, Kyu-Mann

    2015-12-01

    We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of Zn-doped indium tin oxide (ZITO) thin films intended for use as anode contacts in organic light emitting diodes (OLED) devices. These ZITO thin films are deposited by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar + O2 and Ar + H2) at 300°C. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0.1 sccm to 0.5 sccm and from 0.1 sccm to 1 sccm, respectively. The intensity of the (400) peak in the ZITO thin films increases with increasing H2 flow rate whilst the (400) peak was nearly invisible in an atmosphere of Ar + O2. The electrical resistivity of the ZITO thin films increases with increasing O2 flow rate, whereas the electrical resistivity decreases with increasing H2 flow rate. The change of electrical resistivity with changes in the ambient gas composition is mainly interpreted in terms of the charge carrier mobility and the charge carrier concentration. All the films show an average transmittance of over 80% in the visible range. The optical bandgap of the ZITO films increases with increasing H2 flow rates, whereas the optical bandgap of the ZITO films deposited in an O2 atmosphere decreases with increasing O2 flow rates. The current density and the luminance of the OLED devices with ZITO thin films deposited in 1 sccm of H2 ambient gas are the highest among all the films. The optical bandgap energy of ZITO thin films plays a major role in OLED device performance, especially the current density and luminance.

  4. Atmospheric Aerosols at the MAGIC Site

    CERN Document Server

    Garrido, Daniel; Doro, Michele; Font, Lluís; López-Oramas, Alicia; Moralejo, Abelardo

    2013-01-01

    We investigate the performance of the MAGIC telescopes under three simulated atmospheric conditions: an increased aerosol content in the lower part of the troposphere, the presence of thin aerosol over-densities at different heights, and an extremely clean atmosphere. Weshow how the effective area of the telescope system is gradually reduced in the presence of varying concentrations of aerosols whereas the energy threshold rises. Clouds at different heights produce energy and altitude-dependent effects on the performance of the system.

  5. Photoinduced superhydrophilicity of amorphous TiOx-like thin films by a simple room temperature sol-gel deposition and atmospheric plasma jet treatment

    International Nuclear Information System (INIS)

    A room temperature sol gel process of TTIP / iPrOH / H2O /HNO3 sol was applied for the deposition of functional Ti alkoxide thin films on glass and polymeric substrates (PEEK). The unheated – amorphous films become superhydrophilic after 7 minutes of UV exposure which deteriorates after one day of storage in dark, exhibiting stable amphiphilic behavior. Superhydrophilicity is also obtained after 5 min of atmospheric pressure Ar – O2 plasma jet treatment. As the plasma power and the oxygen content of the mixture of the treatment increase (70W, 3.2 -5% O2) the films high hydrophilicity is maintained for many days even in dark atmospheric conditions providing long term hydrophilic coatings

  6. Photoinduced superhydrophilicity of amorphous TiOx-like thin films by a simple room temperature sol-gel deposition and atmospheric plasma jet treatment

    Science.gov (United States)

    Vrakatseli, V. E.; Pagonis, E.; Amanatides, E.; Mataras, D.

    2014-11-01

    A room temperature sol gel process of TTIP / iPrOH / H2O /HNO3 sol was applied for the deposition of functional Ti alkoxide thin films on glass and polymeric substrates (PEEK). The unheated - amorphous films become superhydrophilic after 7 minutes of UV exposure which deteriorates after one day of storage in dark, exhibiting stable amphiphilic behavior. Superhydrophilicity is also obtained after 5 min of atmospheric pressure Ar - O2 plasma jet treatment. As the plasma power and the oxygen content of the mixture of the treatment increase (70W, 3.2 -5% O2) the films high hydrophilicity is maintained for many days even in dark atmospheric conditions providing long term hydrophilic coatings.

  7. Atmospheric pseudohalogen chemistry

    OpenAIRE

    Lary, D. J.

    2004-01-01

    There are at least three reasons why hydrogen cyanide is likely to be significant for atmospheric chemistry. The first is well known, HCN is a product and marker of biomass burning. However, if a detailed ion chemistry of lightning is considered then it is almost certain than in addition to lightning producing NOx, it also produces HOx and HCN. Unlike NOx and HOx, HCN is long-lived and could therefore ...

  8. Fair weather terrestrial atmospheric electricity

    Science.gov (United States)

    Harrison, G.

    Atmospheric electricity is one of the oldest experimental topics in atmospheric science. The fair weather aspects, although having less dramatic effects than thunderstorm electrification, link the microscale behaviour of ion clusters to currents flowing on the global scale. This talk will include a survey of some past measurements and measurement methods, as atmospheric electrical data from a variety of sites and eras are now being used to understand changes in atmospheric composition. Potential Gradient data was the original source of information on the global atmospheric electrical circuit, and similar measurements can now be used to reconstruct past air pollution concentrations, and black carbon loading.

  9. Microbial biodiversity of the atmosphere

    Science.gov (United States)

    Klein, Ann Maureen

    Microorganisms are critical to the functioning of terrestrial and aquatic ecosystems and may also play a role in the functioning of the atmosphere. However, little is known about the diversity and function of microorganisms in the atmosphere. To investigate the forces driving the assembly of bacterial microbial communities in the atmosphere, I measured temporal variation in bacterial diversity and composition over diurnal and inter-day time scales. Results suggest that bacterial communities in the atmosphere markedly vary over diurnal time scales and are likely structured by inputs from both local terrestrial and long-distance sources. To assess the potential functions of bacteria and fungi in the atmosphere, I characterized total and potentially active communities using both RNA- and DNA-based data. Results suggest there are metabolically active microorganisms in the atmosphere that may affect atmospheric functions including precipitation development and carbon cycling. This dissertation includes previously published and unpublished co-authored material.

  10. Atmospheric pressure barrier torch discharge and its optimization for flexible deposition of TiO.sub.2./sub. thin coatings on various surfaces

    Czech Academy of Sciences Publication Activity Database

    Kment, Štěpán; Klusoň, Petr; Žabová, Hana; Churpita, Olexandr; Chichina, Mariya; Čada, Martin; Gregora, Ivan; Krýsa, J.; Hubička, Zdeněk

    2009-01-01

    Roč. 204, č. 5 (2009), s. 667-675. ISSN 0257-8972 R&D Projects: GA AV ČR KJB100100703; GA AV ČR KAN301370701; GA AV ČR KAN400720701; GA ČR GA202/09/0800 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z40720504 Keywords : atmospheric plasma * thin layers * titanium dioxide * PECVD * optical emmision spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.793, year: 2009

  11. Morphology and structure evolution of tin-doped indium oxide thin films deposited by radio-frequency magnetron sputtering: The role of the sputtering atmosphere

    International Nuclear Information System (INIS)

    The microstructure and morphology evolution of tin-doped indium oxide (ITO) thin films deposited by radio-frequency magnetron sputtering in different sputtering atmospheres were investigated by X-ray diffraction, X-ray reflectivity, and atomic force microscopy. The surface roughness w increases with increasing film thickness df, and exhibits a power law behavior w ∼ dfβ. The roughness decreases with increasing O2 flow, while it increases with increasing H2 flow. The growth exponent β is found to be 0.35, 0.75, and 0.98 for depositions in Ar/10%O2, pure Ar, and Ar/10%H2 atmospheres, respectively. The correlation length ξ increases with film thickness also with a power law according to ξ ∼ dfz with exponents z = 0.36, 0.44, and 0.57 for these three different gas atmospheres, respectively. A combination of local and non-local growth modes in 2 + 1 dimensions is discussed for the ITO growth in this work

  12. Greenhouse effect in the atmosphere

    Science.gov (United States)

    Smirnov, B. M.

    2016-04-01

    Average optical atmospheric parameters for the infrared spectrum range are evaluated on the basis of the Earth energetic balance and parameters of the standard atmosphere. The average optical thickness of the atmosphere is u ≈ 2.5 and this atmospheric emission is originated at altitudes below 10 km. Variations of atmospheric radiative fluxes towards the Earth and outward are calculated as a function of the concentration of \\text{CO}2 molecules for the regular model of molecular spectrum. As a result of doubling of the \\text{CO}2 concentration the change of the global Earth temperature is (0.4 +/- 0.2) \\text{K} if other atmospheric parameters are conserved compared to the value (3.0 +/- 1.5) \\text{K} under real atmospheric conditions with the variation of the amount of atmospheric water. An observed variation of the global Earth temperature during the last century (0.8 ^\\circ \\text{C}) follows from an increase of the mass of atmospheric water by 7% or by conversion of 1% of atmospheric water in aerosols.

  13. Properties of YBaCuO superconducting thin films deposited by nitrogen laser evaporation and heat-treated in O2 atmosphere by CW Co2-laser

    International Nuclear Information System (INIS)

    One of successfully applied methods for obtaining high Tc superconducting thin films is the pulsed laser deposition. The advantage of this method is preserving the film stoichiometry in comparison to target if UV eximer lasers, and for Nd-YAG laser in Q-modulation mode are used. In order to obtain the orthorombic phase of YBa2Cu3O7-x, the films are annealed in O2 atmosphere during the deposition process and after that. One problem her is the substrate temperature control. This temperature (Ts) determines to a great extent the vapor condensation mechanism and the chemical-physical processes at the substrate-film interface. This paper describes a method of obtaining high Tc superconducting thin films of YBa2Cu3O7-x by means of an N2 pulse laser and the properties of received films. The substrates used were poly-Al2O3, sapphire, SrTiO3 and Si

  14. Efficient Flame Retardant Thin Films Synthesized by Atmospheric Pressure PECVD through the High Co-deposition Rate of Hexamethyldisiloxane and Triethylphosphate on Polycarbonate and Polyamide-6 Substrates.

    Science.gov (United States)

    Hilt, Florian; Gherardi, Nicolas; Duday, David; Berné, Aurélien; Choquet, Patrick

    2016-05-18

    An innovative approach to produce high-performance and halogen-free flame-retardant thin films at atmospheric pressure is reported. PDMS-based coatings with embedded dopant-rich polyphosphates are elaborated thanks to a straightforward approach, using an atmospheric pressure dielectric barrier discharge (AP-DBD). Deposition conditions have been tailored to elaborate various thin films that can match the fire performance requirements. Morphology, chemical composition, and structure are investigated, and results show that the coatings performances are increased by taking advantage of the synergistic effect of P and Si flame retardant compounds. More specifically, this study relates the possibility to obtain flame retardant properties on PolyCarbonate and PolyAmide-6 thanks to their covering by a 5 μm thick coating, i.e. very thin films for this field of application, yet quite substantial for plasma processes. Hence, this approach enables deposition of flame retardant coatings onto different polymer substrates, providing a versatile fireproofing solution for different natures of polymer substrates. The presence of an expanded charred layer at the surface acts as a protective barrier limiting heat and mass transfer. This latter retains and consumes a part of the PC or PA-6 degradation byproducts and then minimizes the released flammable gases. It may also insulate the substrate from the flame and limit mass transfers of remaining volatile gases. Moreover, reactions in the condensed phase have also been highlighted despite the relatively thin thickness of the deposited layers. As a result of these phenomena, excellent performances are obtained, illustrated by a decrease of the peak of the heat release rate (pHRR) and an increase of the time to ignition (TTI). PMID:27115773

  15. 13. Atmosphere and climate

    International Nuclear Information System (INIS)

    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

  16. Halogens in the atmosphere

    Science.gov (United States)

    Cicerone, R. J.

    1981-01-01

    Atmospheric halogen measurement data are presented for: (1) inorganic and organic gaseous compounds of chlorine, fluorine, bromine and iodine; and (2) chloride, fluoride, bromide and iodine in particulate form and in precipitation. The roles that these data and other, unavailable data play in the determination of the global cycles of the halogens are discussed. It is found that the speciation of the halogen gases in the troposphere is uncertain, with the only inorganic species detected by species-specific methods being HC1 and SF6. It is shown that heterogeneous reactions, both gas-to-particle and particle-to-gas processes, precipitation removal, and sea-salt aerosol generation and fractionation processes, need quantitative investigation to allow progress in estimating halogen sources and sinks. Where practical, quantitative comparisons are made between measured and predicted concentrations.

  17. ZAP: Zurich Atmosphere Purge

    Science.gov (United States)

    Soto, Kurt T.; Lilly, Simon J.; Bacon, Roland; Richard, Johan; Conseil, Simon

    2016-02-01

    ZAP (Zurich Atmosphere Purge) provides sky subtraction for integral field spectroscopy; its approach is based on principal component analysis (PCA) developed for the Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP employs filtering and data segmentation to enhance the inherent capabilities of PCA for sky subtraction. ZAP reduces sky emission residuals while robustly preserving the flux and line shapes of astronomical sources; this method works in a variety of observational situations from sparse fields with a low density of sources to filled fields in which the target source fills the field of view. With the inclusion of both of these situations the method is generally applicable to many different science cases and should also be useful for other instrumentation.

  18. Atmospheric physics. Background - methods - trends

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Ulrich (ed.) [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    2012-11-01

    Presents more than 51 outstanding contributions of DLR-IPA to Atmospheric science. Gives a specific reference to Aerospace aspects. Prepared for educated laymen readers. Self-explaining. Understandable without the need to read references. 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.

  19. Atmospheric turbulence and diffusion research

    International Nuclear Information System (INIS)

    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

  20. A comparative study of thermal annealing effects under various atmospheres on nano-structured CdS thin films prepared by CBD

    International Nuclear Information System (INIS)

    Highlights: •Smooth and uniform CdS thin films were deposited successfully by CBD method. •The influence of CdCl2-assisted annealing under various atmospheres of CdS films has been investigated. •We gave a more detailed research on annealing temperature after identified the most optimal annealing method. •High quality CdS films were obtained with air–CdCl2-assisted treatments at 400 °C for 0.5 h. •GIXRD was used as a new analysis method of CdS in this paper. -- Abstract: Cadmium sulfide (CdS) nanofilms have been deposited on the glass substrate using the chemical bath technique. The effects of CdCl2-assisted annealing under different atmosphere (vacuum, Ar and air) on the structural, morphological and optical properties of CdS nanofilms have been studied. After identifying the optimal annealing atmosphere, we also investigated the CdS thin film annealed at different annealing temperature (300, 400 and 500 °C). Films have been characterized by GI-XRD analysis, scanning electron microscopy, and UV–Vis–NIR spectrophotometer. The as-deposited CdS films have been found to be nanocrystalline in nature with a mixture of two crystallographic phases: a hexagonal phase and a cubic phase. After annealed in air with a CdCl2 coating layer at 400 °C, the films showed pure hexagonal phase, indicating the phase transition of CdS. It was found that the treatment in air with a CdCl2 coating layer increased the crystallinity and the mean grain size of CdS film, which are advantageous to the application in solar cells as a window layer material

  1. Atmospheric lidar predevelopment program (ATLID)

    Science.gov (United States)

    Morancais, Didier; Marini, Andrea E.

    1997-09-01

    The Atmospheric Lidar (ATLID) is the backscatter lidar instrument developed for ESA, under the prime contractorship of MATRA MARCONI SPACE France. This kind of lidar has been selected for flight on an ESA Earth Explorer satellite, and will be based on ATLID concept and technologies. It is part of a multi-payload mission, named Earth Radiation, dedicated to the Earth radiative transfer study for climatology. The lidar will provide information on the atmosphere, such as cloud cover, top height of all cloud types and planetary boundary layer, thin cloud extent, optical depth and polarization. The instrument features a pulsed diode-pumped Nd-YAG laser (1.06 micrometers wavelength) together with a one-axis scanning 60 cm lightweight telescope. A technology pre-development program has been performed in order to raise the maturity of the instrument design. Elegant breadboard models have been realised and submitted to environmental tests. The laser transmitter, the laser thermal control subsystem (capillary-pumped two-phase loop), the diode laser power supply, the avalanche photodiode detection chain, the narrow-band filter, the scan mechanism, and the telescope lightweight primary mirror (C-SiC) have been breadboarded in the frame of the programme. The instrument design and performance have also been consolidated with regards to the successful hardware results.

  2. The composition of planetary atmospheres

    International Nuclear Information System (INIS)

    IR observations have proven to be efficient for the detection of thin atmospheres on faint objects (Triton, Pluto, Io). Also, they were especially successful for the determination of the chemical atmospheric composition of the giant planets and for the related determination of abundance ratios in these planets. Jupiter is the most extensively studied, and IR spectroscopy has led to the discovery of a large number of molecules and to the determination of major abundance ratios: H2/He, D/H, 12C/13C, 15N/14N, N/H, P/N, C/H. The authors' conclusion is that these ratios are close to the cosmic values while other authors conclude to a significant enrichment of most of the elements with respect to H. This controversy is reviewed and analyzed. Concerning the other outer planets, the H2/He ratio, in spite of large uncertainties, seems to be solar, too, and the C/H ratio, following most of the studies, is significantly enriched on Uranus and Neptune. (Auth.)

  3. Atmospheric neutrinos and neutrino oscillations

    International Nuclear Information System (INIS)

    The results on the composition of atmospheric neutrinos interacting in underground detectors and on the rate of atmospheric muon neutrino interactions in the earth surrounding the detectors are reviewed. So far, systematic errors on the neutrino flux and on the electrons and muons neutrino interaction identifications are not yet reliable enough to prove that atmospheric neutrinos oscillate before being detected. (author) 22 refs., 5 figs

  4. Exploring the atmosphere using smartphones

    CERN Document Server

    Monteiro, Martín; Stari, Cecilia; Cabeza, Cecilia; Marti, Arturo C

    2015-01-01

    The characteristics of the inner layer of the atmosphere, the troposphere, are determinant for the 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 flight information system of an aircraft. The experimental results are compared with the International Standard Atmosphere and other simple approximations: isothermal and constant density atmospheres.

  5. Atmospheric pressure chemical vapour deposition of NbSe2-TiSe2 composite thin films

    International Nuclear Information System (INIS)

    Atmospheric pressure chemical vapour deposition of titanium tetrachloride and niobium pentachloride with di-tert-butyl selenide at 550 deg. C was investigated for different precursors' flow rates. Scanning electron microscopy of the films showed that they were composed of two different kinds of plate-like crystallites. Point wavelength dispersive X-ray (WDX) analyses of the crystallites revealed that they either had the NbSe2 or the TiSe2 composition. The presence of the two phases was confirmed by X-ray diffraction (XRD) and the calculated cell parameters indicate that niobium or titanium was not incorporated into each others' lattice. WDX and XRD analyses highlighted how the NbSe2:TiSe2 ratio in the composite films could be controlled by precursor flow rate.

  6. A glossary of atmospheric science

    International Nuclear Information System (INIS)

    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.

  7. 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 dont only provide food, but also the service and atmosphere to their customers. The purpose of this study is to discover the aspects 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.

  8. The virial theorem and planetary atmospheres

    OpenAIRE

    Toth, Viktor T.

    2010-01-01

    We derive a version of the virial theorem that is applicable to diatomic planetary atmospheres that are in approximate thermal equilibrium at moderate temperatures and pressures and are sufficiently thin such that the gravitational acceleration can be considered constant. We contrast a pedagogically inclined theoretical presentation with the actual measured properties of air.

  9. Atmospheric electricity and aerosol-cloud interactions in earth's atmosphere

    Science.gov (United States)

    Manninen, Hanna E.; Tammet, Hannes; Mäkelä, Antti; Haapalainen, Jussi; Mirme, Sander; Nieminen, Tuomo; Franchin, Alessandro; Petäjä, Tuukka; Kulmala, Markku; Hõrrak, Urmas

    2013-05-01

    Firstly, atmospheric ions play an important role in the fair weather electricity in Earth's atmosphere. Small ions, or charged molecular clusters, carry electric currents in the atmosphere. These small ions are continuously present, and their lifetime in lower atmosphere is about one minute. It's essential to find out a connection between the production rate of cluster ions, ion-ion recombination, and ion-aerosol attachment, and their ambient concentrations, in order to understand electrical properties of air. Secondly, atmospheric ions are important for Earth's climate, due to their potential role in secondary aerosol formation, which can lead to increased number of cloud condensation nuclei (CCN), which in turn can change the cloud properties. Our aim is to quantify the connections between these two important roles of air ions based on field observations.

  10. 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.

  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. Models of Pluto's upper atmosphere

    International Nuclear Information System (INIS)

    Best guesses as to the thermal structure and composition of Pluto's atmosphere have led to speculations of substantial loss rates (∼1028 s-1) of methane from the planet over cosmogonic time scales. Results from recent stellar occultation measurements, and using a Parker-type hydrodynamic calculation, show that the loss rates may actually be lower by as much as a factor ∼5, depending upon the efficiency of heating of the atmosphere via the absorption of solar EUV and upon the true atmospheric composition, if the thermal structure of the upper atmosphere is properly taken into account. The loss rate may even be less (by another factor ∼10) if there is minimal heating of the upper atmosphere

  13. Chemistry Of Atmospheric Brown Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey

    2015-05-27

    Organic carbon (OC) accounts for a large fraction of atmospheric aerosol and has profound effects on air quality, atmospheric chemistry and climate forcing. Molecular composition of the OC and its evolution during common processes of atmospheric aging have been a subject of extensive research over the last decade (see reviews of Ervens et al.,1 Hallquist et al.,2 Herckes et al.,3 Carlton et al.,4 Kroll and Seinfeld,5 Rudich et al.,6 and Kanakidou et al.7). Even though many fundamental advances have been reported in these studies, our understanding of the climate-related properties of atmospheric OC is still incomplete and the specific ways in which OC impacts atmospheric environment and climate forcing are just beginning to be understood. This review covers one topic of particular interest in this area –environmental chemistry of light-absorbing aerosol OC and its impact on radiative forcing.

  14. 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.

  15. The Atmospheres of Extrasolar Planets

    CERN Document Server

    Marley, Mark S

    2008-01-01

    The characteristics of irradiated solar system planetary atmospheres have been studied for decades, consequently modern planetary science benefits from an exhaustive body of ground- and space-based data. The study of extrasolar planetary atmospheres, by contrast, is still in its infancy and currently rests on a few score of datapoints, mostly of the transiting planets. This short survey aims not to review this dynamic field but rather stresses the importance of a few theoretical concepts and processes for our understanding of exoplanet atmospheres. Topics covered include atmospheric structure and dynamics, cloud processes and photochemistry of planetary atmospheres. Influences on the albedos, spectra, and colors of extrasolar planets are reviewed and caution is urged in the interpretation of exoplanet colors.

  16. Detection of CO in Triton's atmosphere and the nature of surface-atmosphere interactions

    CERN Document Server

    Lellouch, E; Sicardy, B; Ferron, S; Käufl, H -U

    2010-01-01

    Triton possesses a thin atmosphere, primarily composed of nitrogen, sustained by the sublimation of surface ices. The goal is to determine the composition of Triton's atmosphere and to constrain the nature of surface-atmosphere interactions. We perform high-resolution spectroscopic observations in the 2.32-2.37 $\\mu$m range, using CRIRES at the VLT. From this first spectroscopic detection of Triton's atmosphere in the infrared, we report (i) the first observation of gaseous methane since its discovery in the ultraviolet by Voyager in 1989 and (ii) the first ever detection of gaseous CO in the satellite. The CO atmospheric abundance is remarkably similar to its surface abundance, and appears to be controlled by a thin, CO-enriched, surface veneer resulting from seasonal transport and/or atmospheric escape. The CH$_4$ partial pressure is several times larger than inferred from Voyager. This confirms that Triton's atmosphere is seasonally variable and is best interpreted by the warming of CH$_4$-rich icy grains ...

  17. Cyberinfrastructure for Atmospheric Discovery

    Science.gov (United States)

    Wilhelmson, R.; Moore, C. W.

    2004-12-01

    Each year across the United States, floods, tornadoes, hail, strong winds, lightning, hurricanes, and winter storms cause hundreds of deaths, routinely disrupt transportation and commerce, and result in billions of dollars in annual economic losses . MEAD and LEAD are two recent efforts aimed at developing the cyberinfrastructure for studying and forecasting these events through collection, integration, and analysis of observational data coupled with numerical simulation, data mining, and visualization. MEAD (Modeling Environment for Atmospheric Discovery) has been funded for two years as an NCSA (National Center for Supercomputing Applications) Alliance Expedition. The goal of this expedition has been the development/adaptation of cyberinfrastructure that will enable research simulations, datamining, machine learning and visualization of hurricanes and storms utilizing the high performance computing environments including the TeraGrid. Portal grid and web infrastructure are being tested that will enable launching of hundreds of individual WRF (Weather Research and Forecasting) simulations. In a similar way, multiple Regional Ocean Modeling System (ROMS) or WRF/ROMS simulations can be carried out. Metadata and the resulting large volumes of data will then be made available for further study and for educational purposes using analysis, mining, and visualization services. Initial coupling of the ROMS and WRF codes has been completed and parallel I/O is being implemented for these models. Management of these activities (services) are being enabled through Grid workflow technologies (e.g. OGCE). LEAD (Linked Environments for Atmospheric Discovery) is a recently funded 5-year, large NSF ITR grant that involves 9 institutions who are developing a comprehensive national cyberinfrastructure in mesoscale meteorology, particularly one that can interoperate with others being developed. LEAD is addressing the fundamental information technology (IT) research challenges needed

  18. Effect of glass tempering on microstructure and functional properties of SnO2:F thin film prepared by atmosphere pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    The low-emission glass was prepared via depositing fluorine-doped tin oxide thin film on glass substrate by atmospheric pressure chemical vapor deposition method. The as-deposited low-emission glass was found to present a SnO2:F/SiCxOy/glass sandwich structure via focused ion beam technique and transmission microscopic measurement. After tempering process at ∼ 650 °C with varied periods, the electrical and optical properties of the SnO2:F thin film remained stable for less than 10 min, but decreased dramatically when the tempering period exceeded 10 min, which was mainly due to the oxygen chemisorptions and fluorine ion diffusion. It was observed that the SnO2:F thin films presented uniform polycrystalline nature of cassiterite structure throughout the tempering process. The study has therefore suggested the appropriate tempering conditions for the SnO2:F low-emission glass, and provided a critical guidance for further energy-saving glass applications. - Highlights: • The sandwich structural low-e glass was prepared on an industrial line. • The film showed stable morphology and functional property under low temperature. • The functional property decreased dramatically after long time tempering at 650 °C

  19. Effect of glass tempering on microstructure and functional properties of SnO{sub 2}:F thin film prepared by atmosphere pressure chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Qian [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China); Liu, Qiying [Hangzhou Bluestar New Materials Technology Co., Ltd, Hangzhou, 310012 (China); Li, Ming [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China); Li, Xiang, E-mail: xiang.li@zju.edu.cn [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China); Liu, Yong; Song, Chenlu; Wang, Jianxun [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China); Liu, Junbo [Hangzhou Bluestar New Materials Technology Co., Ltd, Hangzhou, 310012 (China); Shen, Ge [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China); Han, Gaorong, E-mail: hgr@zju.edu.cn [State Key Laboratory for Silicon Materials and Center for Electron Microscopy, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 (China)

    2013-10-01

    The low-emission glass was prepared via depositing fluorine-doped tin oxide thin film on glass substrate by atmospheric pressure chemical vapor deposition method. The as-deposited low-emission glass was found to present a SnO{sub 2}:F/SiC{sub x}O{sub y}/glass sandwich structure via focused ion beam technique and transmission microscopic measurement. After tempering process at ∼ 650 °C with varied periods, the electrical and optical properties of the SnO{sub 2}:F thin film remained stable for less than 10 min, but decreased dramatically when the tempering period exceeded 10 min, which was mainly due to the oxygen chemisorptions and fluorine ion diffusion. It was observed that the SnO{sub 2}:F thin films presented uniform polycrystalline nature of cassiterite structure throughout the tempering process. The study has therefore suggested the appropriate tempering conditions for the SnO{sub 2}:F low-emission glass, and provided a critical guidance for further energy-saving glass applications. - Highlights: • The sandwich structural low-e glass was prepared on an industrial line. • The film showed stable morphology and functional property under low temperature. • The functional property decreased dramatically after long time tempering at 650 °C.

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

    International Nuclear Information System (INIS)

    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)

  1. Photosynthesis in Hydrogen-Dominated Atmospheres

    OpenAIRE

    William Bains; Sara Seager; Andras Zsom

    2014-01-01

    The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H[subscript 2]-dominated atmosphere. If a rocky, H[subscript 2]-dominated planet harbors life, th...

  2. Atmospheric pressure chemical vapour deposition of vanadium arsenide thin films via the reaction of VCl4 or VOCl3 with tBuAsH2

    International Nuclear Information System (INIS)

    Thin films of vanadium arsenide were deposited via the dual-source atmospheric pressure chemical vapour deposition reactions of VCl4 or VOCl3 with tBuAsH2. Using the vanadium precursor VCl4, films were deposited at substrate temperatures of 550–600 °C, which were black-gold in appearance and were found to be metal-rich with high levels of chlorine incorporation. The use of VOCl3 as the vanadium source resulted in films being deposited between 450 and 600 °C and, unlike when using VCl4, were silver in appearance. The films deposited using VOCl3 demonstrated vanadium to arsenic ratios close to 1:1, and negligible chlorine incorporation. Films deposited using either vanadium precursor were identified as VAs using powder X-ray diffraction and possessed borderline metallic/semiconductor resistivities. - Highlights: • Formation of VAs films via atmospheric pressure chemical vapour deposition. • Films formed using VCl4 or VOCl3 and tBuAsH2. • Powder X-ray diffraction showed that crystalline VAs films were deposited. • Films from VOCl3 had a V:As ratio close to 1 with negligible Cl incorporation. • Films were silver and possessed borderline metallic/semiconductor resistivities

  3. The effect of deposition atmosphere on the chemical composition of TiN and ZrN thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Very thin TiN and ZrN films (4 or N2. Auger electron spectroscopy investigations found that films contained a relatively low oxygen concentration, usually below 3.0 at%. Films deposited under residual vacuum or very low N2 pressures (−3 Pa) contained 3–6 at% C atoms in the bulk. This fraction grew to 8–10 at% when the deposition was performed under an atmosphere of 2 × 10−3 Pa CH4. To avoid C atoms incorporation into the bulk a deposition pressure of 10 Pa N2 was required. X-ray photoelectron spectroscopy investigations found that oxygen was mostly bonded in an oxynitride type of compound, while carbon was bonded into a metallic carbide. The presence of C atoms in the chemical composition of the TiN or ZrN improved the measured hardness of the films.

  4. Influence of annealing atmosphere and temperature on photoluminescence of Tb 3+ or Eu 3+-activated zinc silicate thin film phosphors via sol-gel method

    Science.gov (United States)

    Zhang, Q. Y.; Pita, K.; Ye, W.; Que, W. X.

    2002-01-01

    Thin films of Zn 2SiO 4:Tb 3+ or Eu 3+ were deposited on silicon wafers by a sol-gel method. The films exhibited prominent green or red photoluminescence, due to the sharp and strong intra-4f n-shell electronic transitions. The thermogravimetric analysis curve shows a remarkable weight loss in the temperature range 50-400 ° C, and a slow loss at higher temperature. The increases in fluorescence intensity and decay lifetimes of rare-earth ions sensitive to microstructure and chemical components are attributed to OH removal, nano-crystallite formation and the increased surface roughness by treatment of temperature. Strongly enhanced photoluminescence was observed in samples annealed at 950 °C in a nitrogen atmosphere.

  5. On the formation mechanisms of the diffuse atmospheric pressure dielectric barrier discharge in CVD processes of thin silica-like films

    International Nuclear Information System (INIS)

    Pathways of formation and temporal evolution of the diffuse dielectric barrier discharge at atmospheric pressure were experimentally studied in this work by means of optical (fast imaging camera) and electrical diagnostics. The chosen model system is relevant for applications of plasma-enhanced chemical vapor deposition of thin silica-like film on the polymeric substrate, from cost-efficient gas mixtures of Ar/N2/O2/hexamethyldisiloxane. It was found that the discharge can gradually experience the phases of homogeneous low current Townsend-like mode, local Townsend to glow transition and expanding high current density (∼0.7 A cm-2) glow-like mode. While the glow-like current spot occupies momentarily only a small part of the electrode area, its expanding behavior provides uniform treatment of the whole substrate surface. Alternatively, it was observed that a visually uniform discharge can be formed by the numerous microdischarges overlapping over the large electrode area.

  6. Global distribution of Pluto's atmosphere

    International Nuclear Information System (INIS)

    Pluto's volatile atmosphere currently extends essentially uniformly around the globe and has nearly uniform thickness, discounting topographic elevation differences and tidal effects. Although in equilibrium with the surface ice, the atmosphere does not noticeably freeze out on the night side, during eclipses of the Sun by Charon, or at the poles during Pluto's present season near perihelion. The bulk thermal tide is negligible. The rotational and tidal deformations of the atmosphere affect the atmospheric thickness of 0.6--2% for a pure CH4 atmosphere, depending on the unknown mass of Charon, and up to 15% for an atmosphere with high mean molecular weight. An important consequence of the global uniformity of Pluto's atmosphere and the observed CH4 column abundance of 27 +- 7 m--Am is that Pluto's surface is close to 58 K over the entire globe. This compares with the value approx.43 K expected on the basis of insolation and blackbody radiation. We suggest that the explanation for Pluto's elevated surface temperature is the low thermal emissivity of solid CH4, expected on the basis of the absence of a rotational spectrum in the gas. Solid CH4, which covers an appreciable portion of Pluto's surface, can absorb sunlight in the visible and near-infrared bands but lacks opacity at thermal wavelengths to radiate the absorbed energy efficiently

  7. Atmospheric predictability revisited

    Directory of Open Access Journals (Sweden)

    Lizzie S. R. Froude

    2013-06-01

    Full Text Available This article examines the potential to improve numerical weather prediction (NWP by estimating upper and lower bounds on predictability by re-visiting the original study of Lorenz (1982 but applied to the most recent version of the European Centre for Medium Range Weather Forecasts (ECMWF forecast system, for both the deterministic and ensemble prediction systems (EPS. These bounds are contrasted with an older version of the same NWP system to see how they have changed with improvements to the NWP system. The computations were performed for the earlier seasons of DJF 1985/1986 and JJA 1986 and the later seasons of DJF 2010/2011 and JJA 2011 using the 500-hPa geopotential height field. Results indicate that for this field, we may be approaching the limit of deterministic forecasting so that further improvements might only be obtained by improving the initial state. The results also show that predictability calculations with earlier versions of the model may overestimate potential forecast skill, which may be due to insufficient internal variability in the model and because recent versions of the model are more realistic in representing the true atmospheric evolution. The same methodology is applied to the EPS to calculate upper and lower bounds of predictability of the ensemble mean forecast in order to explore how ensemble forecasting could extend the limits of the deterministic forecast. The results show that there is a large potential to improve the ensemble predictions, but for the increased predictability of the ensemble mean, there will be a trade-off in information as the forecasts will become increasingly smoothed with time. From around the 10-d forecast time, the ensemble mean begins to converge towards climatology. Until this point, the ensemble mean is able to predict the main features of the large-scale flow accurately and with high consistency from one forecast cycle to the next. By the 15-d forecast time, the ensemble mean has lost

  8. Scientific investigations of atmospheric processes

    Science.gov (United States)

    1994-01-01

    Research was performed in atmospheric, dynamical, and thermodynamical processes and in other disciplines necessary to accomplish the following tasks: develop procedures for combining generalized radiative transfer codes with dynamic atmospheric model codes; perform diagnostic analysis of atmospheric processes to gain a better understanding of the evolution and development of mesoscale circulation systems and their precipitation structures; and to develop algorithms and software necessary to graphically display diagnostic sets on the MSFC McIDAS and EADS to facilitate scientific study and sensor capability evaluation. Research activities during this reporting period are detailed.

  9. 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

  10. Atmospheric effects of nuclear war

    International Nuclear Information System (INIS)

    A review of recent computer model studies of the global atmospheric consequences of nuclear war is presented. The studies predict that sub-freezing surface temperatures and semi-darkness beneath regional-scale smoke and dust clouds are the most serious long-term atmospheric repercussions following a nuclear exchange. These studies and the subsequent predictions of global ecological disaster by some biologists have aroused considerable contention amongst scientists from many disciplines. Despite this contention, the predictions of the models reviewed here remain unrefuted. However, from the models so far published the severity of the predicted atmospheric effects and their temporal evolution, particularly in the Southern Hemisphere, cannot be accurately forecast

  11. Saturn: atmosphere, ionosphere, and magnetosphere.

    Science.gov (United States)

    Gombosi, Tamas I; Ingersoll, Andrew P

    2010-03-19

    The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere? PMID:20299587

  12. Atmospheric monitoring in MAGIC and data corrections

    Directory of Open Access Journals (Sweden)

    Fruck Christian

    2015-01-01

    Full Text Available A method for analyzing returns of a custom-made “micro”-LIDAR system, operated alongside the two MAGIC telescopes is presented. This method allows for calculating the transmission through the atmospheric boundary layer as well as thin cloud layers. This is achieved by applying exponential fits to regions of the back-scattering signal that are dominated by Rayleigh scattering. Making this real-time transmission information available for the MAGIC data stream allows to apply atmospheric corrections later on in the analysis. Such corrections allow for extending the effective observation time of MAGIC by including data taken under adverse atmospheric conditions. In the future they will help reducing the systematic uncertainties of energy and flux.

  13. Effects of residual hydrogen in sputtering atmosphere on structures and properties of amorphous In-Ga-Zn-O thin films

    International Nuclear Information System (INIS)

    We investigated the effects of residual hydrogen in sputtering atmosphere on subgap states and carrier transport in amorphous In-Ga-Zn-O (a-IGZO) using two sputtering systems with different base pressures of ∼10−4 and 10−7 Pa (standard (STD) and ultrahigh vacuum (UHV) sputtering, respectively), which produce a-IGZO films with impurity hydrogen contents at the orders of 1020 and 1019 cm−3, respectively. Several subgap states were observed by hard X-ray photoemission spectroscopy, i.e., peak-shape near-valence band maximum (near-VBM) states, shoulder-shape near-VBM states, peak-shape near-conduction band minimum (near-CBM) states, and step-wise near-CBM states. It was confirmed that the formation of these subgap states were affected strongly by the residual hydrogen (possibly H2O). The step-wise near-CBM states were observed only in the STD films deposited without O2 gas flow and attributed to metallic In. Such step-wise near-CBM state was not detected in the other films including the UHV films even deposited without O2 flow, substantiating that the metallic In is segregated by the strong reduction effect of the hydrogen/H2O. Similarly, the density of the near-VBM states was very high for the STD films deposited without O2. These films had low film density and are consistent with a model that voids in the amorphous structure form a part of the near-VBM states. On the other hand, the UHV films had high film densities and much less near-VBM states, keeping the possibility that some of the near-VBM states, in particular, of the peak-shape ones, originate from –OH and weakly bonded oxygen. These results indicate that 2% of excess O2 flow is required for the STD sputtering to compensate the effects of the residual hydrogen/H2O. The high-density near-VBM states and the metallic In segregation deteriorated the electron mobility to 0.4 cm2/(V s)

  14. Effects of residual hydrogen in sputtering atmosphere on structures and properties of amorphous In-Ga-Zn-O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Haochun; Ishikawa, Kyohei; Ide, Keisuke [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio, E-mail: kamiya.t.aa@m.titech.ac.jp [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ueda, Shigenori [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-city, Ibaraki 305-0047 (Japan); Ohashi, Naoki [Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-city, Ibaraki 305-0047 (Japan); Kumomi, Hideya [Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

    2015-11-28

    We investigated the effects of residual hydrogen in sputtering atmosphere on subgap states and carrier transport in amorphous In-Ga-Zn-O (a-IGZO) using two sputtering systems with different base pressures of ∼10{sup −4} and 10{sup −7 }Pa (standard (STD) and ultrahigh vacuum (UHV) sputtering, respectively), which produce a-IGZO films with impurity hydrogen contents at the orders of 10{sup 20} and 10{sup 19 }cm{sup −3}, respectively. Several subgap states were observed by hard X-ray photoemission spectroscopy, i.e., peak-shape near-valence band maximum (near-VBM) states, shoulder-shape near-VBM states, peak-shape near-conduction band minimum (near-CBM) states, and step-wise near-CBM states. It was confirmed that the formation of these subgap states were affected strongly by the residual hydrogen (possibly H{sub 2}O). The step-wise near-CBM states were observed only in the STD films deposited without O{sub 2} gas flow and attributed to metallic In. Such step-wise near-CBM state was not detected in the other films including the UHV films even deposited without O{sub 2} flow, substantiating that the metallic In is segregated by the strong reduction effect of the hydrogen/H{sub 2}O. Similarly, the density of the near-VBM states was very high for the STD films deposited without O{sub 2}. These films had low film density and are consistent with a model that voids in the amorphous structure form a part of the near-VBM states. On the other hand, the UHV films had high film densities and much less near-VBM states, keeping the possibility that some of the near-VBM states, in particular, of the peak-shape ones, originate from –OH and weakly bonded oxygen. These results indicate that 2% of excess O{sub 2} flow is required for the STD sputtering to compensate the effects of the residual hydrogen/H{sub 2}O. The high-density near-VBM states and the metallic In segregation deteriorated the electron mobility to 0.4 cm{sup 2}/(V s)

  15. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  16. 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.

  17. Early Earth: Atmosphere's solar shock

    Science.gov (United States)

    Ramirez, Ramses

    2016-06-01

    Frequent storms on the young Sun would have ejected energetic particles and compressed Earth's magnetosphere. Simulations suggest that the particles penetrated the atmosphere and initiated reactions that warmed the planet and fertilized life.

  18. Atmospheric soundings from Mount Abu

    Science.gov (United States)

    Sharma, Som; Sinha, H. S. S.

    2005-06-01

    An atmospheric science laboratory was set up at Gurushikhar, in the campus of PRL's Infrared observatory, in 1994. A variety of scientific instruments were housed in the atmospheric science laboratory to explore the Earth's ionosphere and neutral atmosphere. A powerful Nd-YAG laser based Lidar, a multi-wavelength all sky imaging system, Day-night-airglow photometer/spectrometer and a proton precession magnetometer are in operation along with a surface ozone sampler, a carbon mono-oxide analyzer and a UV radiometer (measures solar ultraviolet irradiance between 280 and 320 nm). This article highlights the neutral density and temperature measurements by the lidar as well as Atmospheric/Ionospheric parameters derived by other instruments.

  19. Atmospheric Methane in Ice Cores

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The reconstruction of air trapped in ice cores provides us the most direct information about atmospheric CH4 variations in the past history. Ice core records from the "Three Poles (Antarctica, Greenland and Tibetan Plateau)" reveal the detailed fluctuations of atmospheric CH4 concentration with time and are allowed to quantify the CH4 differences among latitudes. These data are indispensably in the farther study of the relationship between greenhouse gases and climatic change, and of the past changes in terrestrial CH4 emissions. Ice cores reconstruction indicates that atmospheric CH4 concentration has increased quickly since industrialization, and the present day's level of atmospheric CH4 (1800 ppbv) is unprecedented during the past Glacial-Interglacial climate cycles.

  20. Light atmosphere in hospital wards

    DEFF Research Database (Denmark)

    Stidsen, Lone Mandrup

    Sociocultural aspects of light are important for the user experience of the atmosphere in a ward. According to the Danish Regulation for light in hospitals (DS703, 1983), a home-like feeling is required to support the patients, as they needa pleasant environment for their recovery. The term ‘Light...... Atmosphere’ is explored using methods in the practice of lighting design where qualitative and quantitative methods are used to qualify important aspects of a lighting design. Measurable parameters such as the amount of Lux, composition of CRI and degree of Kelvin is well described so the designer can handle...... Atmosphere' is the focal point developed through the study. Primarily, the model frames the study and serves as a design tool for creating the light atmosphere in hospital wards. First, brain storming is used to open up the field supported by theoretical aspects based on Gernot Böhmes' concept of atmosphere...

  1. 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.

  2. Atmospheric Chemistry and Air Pollution

    OpenAIRE

    Gaffney, Jeffrey S.; Marley, Nancy A.

    2003-01-01

    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...

  3. Laser Atmospheric Studies with VERITAS

    CERN Document Server

    Hui, C M

    2007-01-01

    As a calibrated laser pulse propagates through the atmosphere, the amount of Rayleigh-scattered light arriving at the VERITAS telescopes can be calculated precisely. This technique was originally developed for the absolute calibration of ultra-high-energy cosmic-ray fluorescence telescopes but is also applicable to imaging atmospheric Cherenkov telescopes (IACTs). In this paper, we present two nights of laser data taken with the laser at various distances away from the VERITAS telescopes and compare it to Rayleigh scattering simulations.

  4. Radionuclide dispersion in the atmosphere

    International Nuclear Information System (INIS)

    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)

  5. Atmospheric changes from solar eclipses.

    Science.gov (United States)

    Aplin, K L; Scott, C J; Gray, S L

    2016-09-28

    This article reviews atmospheric changes associated with 44 solar eclipses, beginning with the first quantitative results available, from 1834 (earlier qualitative accounts also exist). Eclipse meteorology attracted relatively few publications until the total solar eclipse of 16 February 1980, with the 11 August 1999 eclipse producing the most papers. Eclipses passing over populated areas such as Europe, China and India now regularly attract scientific attention, whereas atmospheric measurements of eclipses at remote locations remain rare. Many measurements and models have been used to exploit the uniquely predictable solar forcing provided by an eclipse. In this paper, we compile the available publications and review a subset of them chosen on the basis of importance and novelty. Beyond the obvious reduction in incoming solar radiation, atmospheric cooling from eclipses can induce dynamical changes. Observations and meteorological modelling provide evidence for the generation of a local eclipse circulation that may be the origin of the 'eclipse wind'. Gravity waves set up by the eclipse can, in principle, be detected as atmospheric pressure fluctuations, though theoretical predictions are limited, and many of the data are inconclusive. Eclipse events providing important early insights into the ionization of the upper atmosphere are also briefly reviewed.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550760

  6. Carbon Nitride Thin Films Deposited by Plasma Assisted Nd∶YAG Laser Ablation of Graphite in N2+H2 Atmosphere

    Institute of Scientific and Technical Information of China (English)

    YU Wei; WANG Shufang; ZHANG Lianshui; LI Xiaowei; FU Guangsheng

    2001-01-01

    Carbon nitride thin films are deposited on silicon wafers by 532 nm Nd∶YAG laser ablation of graphite in the N2+H2 atmosphere assisted by a dc glow discharge plasma at a higher gas pressure of about 4.0 kPa. The properties of the thin films are investigated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The results show that the deposited films are composed of α-C3N4, β-C3N4 phase and have the N/C atomic ratio of 2.01. The optical emission spectroscopy (OES) studies indicate that the introduction of a dc glow discharge and the adoption of a higher gas pressure during the film deposition are favorable to the net generation of the atomic N, CN radicals and N+2 in B2Σ+u excited state in the plasma, which are considered to play a major role in the synthesis of carbon nitride.

  7. Cu-Doped ZnO Thin Films Deposited by a Sol-Gel Process Using Two Copper Precursors: Gas-Sensing Performance in a Propane Atmosphere

    Directory of Open Access Journals (Sweden)

    Heberto Gómez-Pozos

    2016-01-01

    Full Text Available A study on the propane gas-sensing properties of Cu-doped ZnO thin films is presented in this work. The films were deposited on glass substrates by sol-gel and dip coating methods, using zinc acetate as a zinc precursor, copper acetate and copper chloride as precursors for doping. For higher sensitivity values, two film thickness values are controlled by the six and eight dippings, whereas for doping, three dippings were used, irrespective of the Cu precursor. The film structure was analyzed by X-ray diffractometry, and the analysis of the surface morphology and film composition was made through scanning electron microscopy (SEM and secondary ion mass spectroscopy (SIMS, respectively. The sensing properties of Cu-doped ZnO thin films were then characterized in a propane atmosphere, C3H8, at different concentration levels and different operation temperatures of 100, 200 and 300 °C. Cu-doped ZnO films doped with copper chloride presented the highest sensitivity of approximately 6 × 104, confirming a strong dependence on the dopant precursor type. The results obtained in this work show that the use of Cu as a dopant in ZnO films processed by sol-gel produces excellent catalysts for sensing C3H8 gas.

  8. Effects of annealing in nitrogen atmosphere and HCl-etching on the photoluminescence spectra of spray-deposited CdS:In thin films

    International Nuclear Information System (INIS)

    The aim of this work is to find the effect of processing on the photoluminescence (PL) of spray-deposited CdS:In thin films. So the PL spectra of the as-deposited, annealed and HCl-etched CdS:In thin films prepared by the spray pyrolysis (SP) technique were recorded at T = 23 K. The yellow and red bands were observed in the spectrum of the as-deposited film beside bands with weaker intensity in the infrared region. The PL signal was weakened by annealing in nitrogen atmosphere at T = 400 deg. C and HCl-etching. A deconvolution peak fit was established to find the effects of these treatments on the different bands. The spectrum of the as-deposited film was deconvoluted to 12 peaks, which were reduced to 6 peaks after both treatments. It was found that both treatments have approximately the same effects on the PL spectra; that is they removed most of the peaks and shoulders in the red and infrared regions and attenuated most of the peaks in the yellow region. Some peaks were blue-shifted after annealing which was explained by the growth of nanocrystallites due to the thermal stress that results from the different expansion coefficients of the film and the substrate. These changes were accompanied by a phase change from the mixed (cubic and hexagonal) phase to the hexagonal phase as shown in the X-ray diffractograms.

  9. Characteristics of SiOX thin films deposited by atmospheric pressure chemical vapor deposition using a double-discharge system

    International Nuclear Information System (INIS)

    SiOX thin films were deposited using a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar from a remote-type dielectric barrier discharges (DBD) source, with/without the additional direct-type DBD just above the substrate (double discharge), and the effect of the double discharge on the characteristics of the SiOX thin film was investigated. The increase of HMDS flow rate and the decrease of oxygen flow rate in the gas mixture increased the SiOX-thin-film deposition rate. The improvement of the mechanical properties for SiOX film, in addition to the increase of deposition rate, is believed to be related not only to the higher gas dissociation because of the higher power deposition but also to the lesser recombination of oxygen atoms and dissociated HMDS due to the shorter diffusion length to the substrate.

  10. Composition, Chemistry, and Climate of the Atmosphere. 2: Mean properties of the atmosphere

    Science.gov (United States)

    Singh, Hanwant B. (Editor); Salstein, David A.

    1994-01-01

    The atmosphere can be defined as the relatively thin gaseous envelope surrounding the entire planet Earth. It possesses a number of properties related to its physical state and chemical composition, and it undergoes a variety of internal processes and external interactions that can either maintain or alter these properties. Whereas descriptions of the atmosphere's chemical properties form much of the remaining chapters of this book, the present chapter will highlight the atmosphere's gases, and these define its temperature structure. In contrast, the larger-scale motions comprise the winds, the global organization of which is often referred to as the general circulation. The framework of the dynamical and thermodynamical laws, including the three principles of conversation of mass, momentum, and energy, are fundamental in describing both the internal processes of the atmosphere and its external interactions. The atmosphere is not a closed system, because it exchanges all three of these internally conservative quantities across the atmosphere's boundary below and receives input from regions outside it. Thus surface fluxes of moisture, momentum, and heat occur to and from the underlying ocean and land. The atmosphere exchanges very little mass and momentum with space, though it absorbs directly a portion of the solar radiational energy received from above.

  11. Atmospheric radar sounding

    Science.gov (United States)

    Crane, R. K.

    1972-01-01

    Monostatic and bistatic radar techniques for the measurement of the structure of volume targets in the troposphere and lower stratosphere are reviewed. The targets considered are thin turbulent layers in the lower stratosphere and rain in the troposphere. The measurements of scattering from thin turbulent layers show that layers are generally detected at or near the tropopause, and in 31 out of 34 sets of measurements, layers were detected above the tropopause in the lower 10 km of the stratosphere. The threshold for turbulent layer detection corresponds to an equivalent thickness product of ten to the minus 13th power times the cube root of m at a range of 100 km and for layers with less than 1000 m thickness. The measurement of scattering by rain shows that in the New England area both convective and widespread rain consists of a number of small cells. On average, the cells appear to have a half-intensity width of 3 to 4 km as measured with a radar system with a 1.8 km resolution cell size for cells at 100 km range.

  12. Effect of Heat Treatment Under Nitrogen Atmosphere on Sprayed Fluorine Doped In2O3 Thin Films

    Science.gov (United States)

    Beji, Nasreddine; Ajili, Mejda; Turki, Najoua Kamoun

    2016-07-01

    Fluorine-doped indium oxide thin films (In2O3:F) were prepared at 500°C for different fluorine concentrations (0 at.%, 2 at.%, 6 at.% and 10 at.%) using the chemical spray pyrolysis technique. Structure and surface morphology of these films were characterized by x-ray diffraction (XRD) and atomic force microscopy (AFM). XRD analysis revealed that fluorine doped In2O3 thin films exhibit a centered cubic structure with the (400) preferential orientation. The change of the preferential reflection plane from (222) to (400) was found after doping. The doping optimum concentration of thin film crystal structure is obtained witha fluorine ratio equal to 2 at.%. The crystallinity improvement of In2O3:F (2 at.%) film is detected after annealing at 200°C, 300°C, and 400°C in nitrogen gas for 45 min. Transmission and reflection spectra measurements were performed over the wavelength range of 250-2500 nm. The band gap energy increase from 3.10 eV to 3.45 eV was detected after treatment at 400°C. In parallel, the electrical resistivity, deduced from Hall effect measurements, decreases from 428.90 × 10-4 Ω cm to 6.58 × 10-4 Ω cm.

  13. Work on Planetary Atmospheres and Planetary Atmosphere Probes

    Science.gov (United States)

    Lester, Peter

    1999-01-01

    A summary final report of work accomplished is presented. Work was performed in the following areas: (1) Galileo Probe science analysis, (2) Galileo probe Atmosphere Structure Instrument, (3) Mars Pathfinder Atmosphere Structure/Meteorology instrument, (4) Mars Pathfinder data analysis, (5) Science Definition for future Mars missions, (6) Viking Lander data analysis, (7) winds in Mars atmosphere Venus atmospheric dynamics, (8) Pioneer Venus Probe data analysis, (9) Pioneer Venus anomaly analysis, (10) Discovery Venus Probe Titan probe instrument design, and (11) laboratory studies of Titan probe impact phenomena. The work has resulted in more than 10 articles published in archive journals, 2 encyclopedia articles, and many working papers. This final report is organized around the four planets on which there was activity, Jupiter, Mars, Venus, and Titan, with a closing section on Miscellaneous Activities. A major objective was to complete the fabrication, test, and evaluation of the atmosphere structure experiment on the Galileo probe, and to receive, analyze and interpret data received from the spacecraft. The instrument was launched on April 14, 1989. Calibration data were taken for all experiment sensors. The data were analyzed, fitted with algorithms, and summarized in a calibration report for use in analyzing and interpreting data returned from Jupiter's atmosphere. The sensors included were the primary science pressure, temperature and acceleration sensors, and the supporting engineering temperature sensors. Computer programs were written to decode the Experiment Data Record and convert the digital numbers to physical quantities, i.e., temperatures, pressures, and accelerations. The project office agreed to obtain telemetry of checkout data from the probe. Work to extend programs written for use on the Pioneer Venus project included: (1) massive heat shield ablation leading to important mass loss during entry; and (2) rapid planet rotation, which introduced

  14. 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.

  15. 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

  16. Tutorial models of the climate and habitability of Proxima Centauri b: a thin atmosphere is sufficient to distribute heat given low stellar flux

    CERN Document Server

    Goldblatt, Colin

    2016-01-01

    Proxima Centauri b, an Earth-size planet in the habitable zone of our nearest stellar neighbour, has just been discovered. A theoretical framework of synchronously rotating planets, in which the risk of a runaway greenhouse on the sunlight side and atmospheric collapse on the reverse side are mutually ameliorated via heat transport is discussed. This is developed via simple (tutorial) models of the climate. These show that lower incident stellar flux means that less heat transport, so less atmospheric mass, is required. The incident stellar flux at Proxima Centauri b is indeed low, which may help enhance habitability if it has suffered some atmospheric loss or began with a low volatile inventory.

  17. Atmospheric corrosion of mild steel

    Directory of Open Access Journals (Sweden)

    Morcillo, M.

    2011-10-01

    Full Text Available The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a the morphology of steel corrosion products and corrosion product layers; and b long-term atmospheric corrosion ( > 10 years.

    La corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a morfología de los productos de corrosión del acero y capas de productos de corrosión, y b corrosión atmosférica a larga duración (> 10 años.

  18. 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.

  19. Frontiers of Exoplanet Atmosphere Characterization

    Science.gov (United States)

    Kreidberg, Laura

    2016-01-01

    Exoplanet atmosphere characterization has the potential to reveal the origins, nature, and even habitability of distant worlds. In this dissertation talk, I will present work that is a step toward realizing that potential for a diverse group of four extrasolar planets. I will discuss the results of intensive observational campaigns with the Hubble and Spitzer Space Telescopes to study the atmospheres of the super-Earth GJ 1214b and the hot Jupiters WASP-43b, WASP-12b, and WASP-103b. For GJ 1214b, I measured an unprecedentedly precise near-infrared transmission spectrum that definitively reveals the presence of clouds in the planet's atmosphere. For WASP-43b and WASP-12b, I also obtained very precise spectra. These exhibit water features at high confidence (>7 sigma). The retrieved water abundance for WASP-43b extends the well-known Solar System trend of decreasing atmospheric metallicity with increasing planet mass. The detection of water for WASP-12b marks the first spectroscopic identification of a molecule in the planet's atmosphere and implies that it has solar composition, ruling out carbon-to-oxygen ratios greater than unity. For WASP-103b, I will present preliminary results from the new technique of phase-resolved spectroscopy that constrain the planet's temperature structure, dynamics, and energy budget. Taken together, these results provide a foundation for comparative planetology beyond the Solar System and the investigation of Earth-like, potentially habitable planets with future observing facilities.

  20. MARCS model atmospheres

    CERN Document Server

    Plez, Bertrand

    2008-01-01

    In this review presented at the Symposium A stellar journey in Uppsala, June 2008, I give my account of the historical development of the MARCS code from the first version published in 1975 and its premises to the 2008 grid. It is shown that the primary driver for the development team is the science that can be done with the models, and that they constantly strive to include the best possible physical data. A few preliminary comparisons of M star model spectra to spectrophotometric observations are presented. Particular results related to opacity effects are discussed. The size of errors in the spectral energy distribution (SED) and model thermal stratification are estimated for different densities of the wavelength sampling. The number of points used in the MARCS 2008 grid (108000) is large enough to ensure errors of only a few K in all models of the grid, except the optically very thin layers of metal-poor stars. Errors in SEDs may reach about 10% locally in the UV. The published sampled SEDs are thus appro...

  1. Atmospheric changes from solar eclipses

    CERN Document Server

    Aplin, Karen; Gray, Suzanne

    2016-01-01

    This article reviews atmospheric changes associated with 44 solar eclipses, beginning with the first quantitative results available, from 1834 (earlier qualitative, accounts also exist). Eclipse meteorology attracted relatively few publications until the total solar eclipse of 16 February 1980, with the 11 August 1999 eclipse producing the most papers. Eclipses passing over populated areas such as Europe, China and India now regularly attract scientific attention, whereas atmospheric measurements of eclipses at remote locations remain rare. Many measurements and models have been used to exploit the uniquely predictable solar forcing provided by an eclipse. In this paper we compile the available publications and review a sub-set of them chosen on the basis of importance and novelty. Beyond the obvious reduction in incoming solar radiation, atmospheric cooling from eclipses can induce dynamical changes. Observations and meteorological modelling provide evidence for the generation of a local eclipse circulation ...

  2. Atmospheres of Jupiter and Saturn

    International Nuclear Information System (INIS)

    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)

  3. 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.

  4. Interaction of Atmospheric Plasma Vortices

    Science.gov (United States)

    Izhovkina, N. I.; Artekha, S. N.; Erokhin, N. S.; Mikhailovskaya, L. A.

    2016-06-01

    Atmospheric electric fields, connected with the ionization of particles and plasma processes, occur in the fields of pressure gradients of mosaic mesh topology. Atmospheric aerosol particles play a significant role in the vortex generation. The Coriolis force and the motion of charged particles in the geomagnetic field lead to gyrotropy of the atmosphere and ionosphere. Occurrence of plasma vortices is stochastically determined for such an inhomogeneous gyrotropic medium. The geomagnetic field influences the change of structures of inhomogeneous media in the process of excitation of plasma vortices and their interaction. If colliding vortices are centered on the one geomagnetic line, the merge of vortices and the generation of a joint powerful vortex are possible. If a collision of vortices with centers at different geomagnetic field lines occurs, then the emergence of areas of heating and jet streams and the generation of new vortices are possible.

  5. Cumulant expansions for atmospheric flows

    CERN Document Server

    Ait-Chaalal, Farid; Meyer, Bettina; Marston, J B

    2015-01-01

    The equations governing atmospheric flows are nonlinear, and consequently the hierarchy of cumulant equations is not closed. But because atmospheric flows are inhomogeneous and anisotropic, the nonlinearity may manifests itself only weakly through interactions of mean fields with disturbances such as thermals or eddies. In such situations, truncations of the hierarchy of cumulant equations hold promise as a closure strategy. We review how truncations at second order can be used to model and elucidate the dynamics of turbulent atmospheric flows. Two examples are considered. First, we study the growth of a dry convective boundary layer, which is heated from below, leading to turbulent upward energy transport and growth of the boundary layer. We demonstrate that a quasilinear truncation of the equations of motion, in which interactions of disturbances among each other are neglected but interactions with mean fields are taken into account, can successfully capture the growth of the convective boundary layer. Seco...

  6. Interaction of Atmospheric Plasma Vortices

    Science.gov (United States)

    Izhovkina, N. I.; Artekha, S. N.; Erokhin, N. S.; Mikhailovskaya, L. A.

    2016-08-01

    Atmospheric electric fields, connected with the ionization of particles and plasma processes, occur in the fields of pressure gradients of mosaic mesh topology. Atmospheric aerosol particles play a significant role in the vortex generation. The Coriolis force and the motion of charged particles in the geomagnetic field lead to gyrotropy of the atmosphere and ionosphere. Occurrence of plasma vortices is stochastically determined for such an inhomogeneous gyrotropic medium. The geomagnetic field influences the change of structures of inhomogeneous media in the process of excitation of plasma vortices and their interaction. If colliding vortices are centered on the one geomagnetic line, the merge of vortices and the generation of a joint powerful vortex are possible. If a collision of vortices with centers at different geomagnetic field lines occurs, then the emergence of areas of heating and jet streams and the generation of new vortices are possible.

  7. Smooth YBa2Cu3O7-x thin films prepared by pulsed laser deposition in O2/Ar atmosphere

    DEFF Research Database (Denmark)

    Kyhle, Anders; Skov, Johannes; Hjorth, Søren; Rasmussen, Inge; Hansen, Jørn Bindslev

    1994-01-01

    We report on pulsed laser deposition of YBa2Cu3O7-x in a diluted O2/Ar gas resulting in thin epitaxial films which are almost outgrowth-free. Films were deposited on SrTiO3 or MgO substrates around 800-degrees-C at a total chamber pressure of 1.0 mbar, varying the argon partial pressure from 0 to 0.......6 mbar. The density of boulders and outgrowths usual for laser deposited films varies strongly with Ar pressure: the outgrowth density is reduced from 1.4 x 10(7) to 4.5 x 10(5) cm-2 with increasing Ar partial pressure, maintaining a critical temperature T(c,zero) almost-equal-to 90 K and a transport...

  8. Microplasma jet at atmospheric pressure

    International Nuclear Information System (INIS)

    A nitrogen microplasma jet operated at atmospheric pressure was developed for treating thermally sensitive materials. For example, the plasma sources in treatment of vulnerable biological materials must operate near the room temperature at the atmospheric pressure, without any risk of arcing or electrical shock. The microplasma jet device operated by an electrical power less than 10 W exhibited a long plasma jet of about 6.5 cm with temperature near 300 K, not causing any harm to human skin. Optical emission measured at the wide range of 280-800 nm indicated various reactive species produced by the plasma jet

  9. 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.

  10. Atmospheric Neutrinos: Status and Prospects

    CERN Document Server

    Choubey, Sandhya

    2016-01-01

    We present an overview of the current status of neutrino oscillation studies at atmospheric neutrino experiments. While the current data gives some tentalising hints regarding the neutrino mass hierarchy, octant of $\\theta_{23}$ and $\\delta_{CP}$, the hints are not statistically significant. We summarise the sensitivity to these sub-dominant three-generation effects from the next-generation proposed atmospheric neutrino experiments. We next present the prospects of new physics searches such as non-standard interactions, sterile neutrinos and CPT violation studies at these experiments.

  11. Atmospheric chemistry-climate feedbacks

    OpenAIRE

    Raes, Frank; Liao, Hong; Chen, Wei-Ting; Seinfeld, John H.

    2010-01-01

    We extend the theory of climate feedbacks to include atmospheric chemistry. A change in temperature caused by a radiative forcing will include, in general, a contribution from the chemical change that is fed back into the climate system; likewise, the change in atmospheric burdens caused by a chemical forcing will include a contribution from the associated climate change that is fed back into the chemical system. The theory includes two feedback gains, G_(che) and G_(cli). G_(che) is defined ...

  12. Atmospheric contaminant sensor, book 1

    Science.gov (United States)

    Scott, B. W.; Stuart, J. H.

    1972-01-01

    Design and fabrication of a mass spectrometer system for use as an atmospheric monitor by submarine is reported. The performance design goals are presented. The operation of the system is essentially automatic, providing continuous display of the partial pressures of the principal atmospheric constituents and a pushbutton update display of two freon trace contaminants. The freon update cycle takes 15 or 30 seconds, depending on which are measured. Trouble free, long term, reliable operation, and ease of maintenance are the primary system requirements. The requirement of the freon detection with high sensitivity and high resolution made redesign of the overall analyzer housing and magnet necessary.

  13. Atmospheric Pressure Chemical Vapor Deposition of CdTe for High-Efficiency Thin-Film PV Devices; Annual Report, 26 January 1998-25 January 1999

    International Nuclear Information System (INIS)

    ITN's 3-year project, titled ''Atmospheric Pressure Chemical Vapor Deposition (APCVD) of CdTe for High-Efficiency Thin-Film Photovoltaic (PV) Devices,'' has the overall objectives of improving thin-film CdTe PV manufacturing technology and increasing CdTe PV device power conversion efficiency. CdTe deposition by APCVD employs the same reaction chemistry as has been used to deposit 16%-efficient CdTe PV films, i.e., close-spaced sublimation, but employs forced convection rather than diffusion as a mechanism of mass transport. Tasks of the APCVD program center on demonstrating APCVD of CdTe films, discovering fundamental mass-transport parameters, applying established engineering principles to the deposition of CdTe films, and verifying reactor design principles that could be used to design high-throughput, high-yield manufacturing equipment. Additional tasks relate to improved device measurement and characterization procedures that can lead to a more fundamental understanding of CdTe PV device operation, and ultimately, to higher device conversion efficiency and greater stability. Specifically, under the APCVD program, device analysis goes beyond conventional one-dimensional device characterization and analysis toward two-dimension measurements and modeling. Accomplishments of the first year of the APCVD subcontract include: selection of the Stagnant Flow Reactor design concept for the APCVD reactor, development of a detailed reactor design, performance of detailed numerical calculations simulating reactor performance, fabrication and installation of an APCVD reactor, performance of dry runs to verify reactor performance, performance of one-dimensional modeling of CdTe PV device performance, and development of a detailed plan for quantification of grain-boundary effects in polycrystalline CdTe devices

  14. Effect of the substrate on the properties of ZnO-MgO thin films grown by atmospheric pressure metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Huerta, A.M., E-mail: atohuer@hotmail.com [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Brachetti-Sibaja, S.B. [Alumna del postgrado en Tecnologia Avanzada del CICATA-IPN, Unidad Altamira IPN, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Arenas-Alatorre, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000, D.F. (Mexico); Rodriguez-Pulido, A. [Unidad Profesional Adolfo Lopez Mateos, Luis Enrique Erro s/n, 07738, D. F. (Mexico)

    2011-07-01

    The ZnO-MgO alloys possess attractive properties for possible applications in optoelectronic and display devices; however, the optical properties are strongly dependent on the deposition parameters. In this work, the effect of the glassy and metallic substrates on the structural, morphological and optical properties of ZnO-MgO thin films using atmospheric pressure metal-organic chemical vapor deposition was investigated at relatively low deposition temperature, 500 deg. C. Magnesium and zinc acetylacetonates were used as the metal-organic source. X-ray diffraction experiments provided evidence that the kind of substrates cause a deviation of c-axis lattice constant due to the constitution of a oxide mixture (ZnO and MgO) in combination with different intermetallic compounds(Mg{sub 2}Zn{sub 11} and Mg{sub 4}Zn{sub 7}) in the growth films. The substitutional and interstitial sites of Mg{sup 2+} instead of Zn{sup 2+} ions in the lattice are the most probable mechanism to form intermetallic compounds. The optical parameters as well as thickness of the films were calculated by Spectroscopic Ellipsometry using the classical dispersion model based on the sum of the single and double Lorentz and Drude oscillators in combination with Kato-Adachi equations, as well as X-ray reflectivity.

  15. Effect of the substrate on the properties of ZnO-MgO thin films grown by atmospheric pressure metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    The ZnO-MgO alloys possess attractive properties for possible applications in optoelectronic and display devices; however, the optical properties are strongly dependent on the deposition parameters. In this work, the effect of the glassy and metallic substrates on the structural, morphological and optical properties of ZnO-MgO thin films using atmospheric pressure metal-organic chemical vapor deposition was investigated at relatively low deposition temperature, 500 deg. C. Magnesium and zinc acetylacetonates were used as the metal-organic source. X-ray diffraction experiments provided evidence that the kind of substrates cause a deviation of c-axis lattice constant due to the constitution of a oxide mixture (ZnO and MgO) in combination with different intermetallic compounds(Mg2Zn11 and Mg4Zn7) in the growth films. The substitutional and interstitial sites of Mg2+ instead of Zn2+ ions in the lattice are the most probable mechanism to form intermetallic compounds. The optical parameters as well as thickness of the films were calculated by Spectroscopic Ellipsometry using the classical dispersion model based on the sum of the single and double Lorentz and Drude oscillators in combination with Kato-Adachi equations, as well as X-ray reflectivity.

  16. Effect of Growth Parameters and Annealing Atmosphere on the Properties of Cu2ZnSnS4 Thin Films Deposited by Cosputtering

    Directory of Open Access Journals (Sweden)

    Arun Khalkar

    2013-01-01

    Full Text Available Cu2ZnSnS4 (CZTS thin films were deposited using the cosputtering technique. The growth parameters, such as working pressure, target powers, and postannealing atmosphere, were optimized for CZTS films deposition. A comparative study between post annealing using sulfur vapor in a quartz tube furnace and sulfurization chamber using H2S gas was carried out to optimize the kesterite Cu2ZnSnS4 phase. 10 min annealing at 530°C in the furnace in sulfur vapor eliminated all the secondary phases and formed kesterite Cu2ZnSnS4. The diffusion of sulfur in the film during the annealing process enhanced the crystallinity of the film. The kesterite Cu2ZnSnS4 phase was confirmed by X-ray diffraction, Raman scattering, and optical measurements. The film showed phonon peaks corresponding to the kesterite CZTS, high-absorption coefficient (1.1 × 105 cm−1, and desired optical direct band gap (1.5 eV.

  17. Influence of RF excitation during pulsed laser deposition in oxygen atmosphere on the structural properties and luminescence of nanocrystalline ZnO:Al thin films

    International Nuclear Information System (INIS)

    Thin ZnO:Al layers were deposited by pulsed laser deposition in vacuum and in oxygen atmosphere at gas pressures between 10 and 70 Pa and by applying radio-frequency (RF) plasma. Grazing incidence small angle x-ray scattering and grazing incidence x-ray diffraction (GIXRD) data showed that an increase in the oxygen pressure leads to an increase in the roughness, a decrease in the sample density, and changes in the size distribution of nanovoids. The nanocrystal sizes estimated from GIXRD were around 20 nm, while the sizes of the nanovoids increased from 1 to 2 nm with the oxygen pressure. The RF plasma mainly influenced the nanostructural properties and point defects dynamics. The photoluminescence consisted of three contributions, ultraviolet (UV), blue emission due to Zn vacancies, and red emission, which are related to an excess of oxygen. The RF excitation lowered the defect level related to blue emission and narrowed the UV luminescence peak, which indicates an improvement of the structural ordering. The observed influence of the deposition conditions on the film properties is discussed as a consequence of two main effects: the variation of the energy transfer from the laser plume to the growing film and changes in the growth chemistry

  18. Influence of RF excitation during pulsed laser deposition in oxygen atmosphere on the structural properties and luminescence of nanocrystalline ZnO:Al thin films

    Energy Technology Data Exchange (ETDEWEB)

    Meljanac, Daniel, E-mail: dmeljan@irb.hr; Plodinec, Milivoj; Siketić, Zdravko; Gracin, Davor [Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb (Croatia); Juraić, Krunoslav [Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia and Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/IV, 8010 Graz (Austria); Krstulović, Nikša; Salamon, Krešimir; Skenderović, Hrvoje; Kregar, Zlatko; Rakić, Iva Šrut [Institute of Physics, Bijenička 46, 10000 Zagreb (Croatia); Bernstorff, Sigrid [Elettra-Sincrotrone Trieste, SS 14, Km 163.5, I-34049 Basovizza (TS) (Italy)

    2016-03-15

    Thin ZnO:Al layers were deposited by pulsed laser deposition in vacuum and in oxygen atmosphere at gas pressures between 10 and 70 Pa and by applying radio-frequency (RF) plasma. Grazing incidence small angle x-ray scattering and grazing incidence x-ray diffraction (GIXRD) data showed that an increase in the oxygen pressure leads to an increase in the roughness, a decrease in the sample density, and changes in the size distribution of nanovoids. The nanocrystal sizes estimated from GIXRD were around 20 nm, while the sizes of the nanovoids increased from 1 to 2 nm with the oxygen pressure. The RF plasma mainly influenced the nanostructural properties and point defects dynamics. The photoluminescence consisted of three contributions, ultraviolet (UV), blue emission due to Zn vacancies, and red emission, which are related to an excess of oxygen. The RF excitation lowered the defect level related to blue emission and narrowed the UV luminescence peak, which indicates an improvement of the structural ordering. The observed influence of the deposition conditions on the film properties is discussed as a consequence of two main effects: the variation of the energy transfer from the laser plume to the growing film and changes in the growth chemistry.

  19. Photosynthesis in Hydrogen-Dominated Atmospheres

    Directory of Open Access Journals (Sweden)

    William Bains

    2014-11-01

    Full Text Available The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H2-dominated atmosphere. If a rocky, H2-dominated planet harbors life, then that life is likely to convert atmospheric carbon into methane. Outgassing may also build an atmosphere in which methane is the principal carbon species. We describe the possible chemical routes for photosynthesis starting from methane and show that less energy and lower energy photons could drive CH4-based photosynthesis as compared with CO2-based photosynthesis. We find that a by-product biosignature gas is likely to be H2, which is not distinct from the hydrogen already present in the environment. Ammonia is a potential biosignature gas of hydrogenic photosynthesis that is unlikely to be generated abiologically. We suggest that the evolution of methane-based photosynthesis is at least as likely as the evolution of anoxygenic photosynthesis on Earth and may support the evolution of complex life.

  20. Detection of Atmospheric Composition Based on Lidar

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinye; Tong Yala; Yang Xiaoling; Gong Jiaoli [School of science, Hubei University of Technology, Wuhan 430068 (China); Gong Wei, E-mail: yezi.zh@163.com [State Key Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079 (China)

    2011-02-01

    A summary overview about the types of lidar and their own applications on atmosphere detection is presented. Measurement of atmospheric aerosols by Mie lidar and Raman lidar is focused. The vertical profiles of aerosols in the atmosphere are retrieved. And at the same time, through analyzing aerosol vertical content distribution, the atmosphere boundary layer and the cloud are also observed. All the results show that the lidar has good performance on detecting the atmospheric composition.

  1. Detection of Atmospheric Composition Based on Lidar

    International Nuclear Information System (INIS)

    A summary overview about the types of lidar and their own applications on atmosphere detection is presented. Measurement of atmospheric aerosols by Mie lidar and Raman lidar is focused. The vertical profiles of aerosols in the atmosphere are retrieved. And at the same time, through analyzing aerosol vertical content distribution, the atmosphere boundary layer and the cloud are also observed. All the results show that the lidar has good performance on detecting the atmospheric composition.

  2. Applications of theoretical methods in atmospheric science

    DEFF Research Database (Denmark)

    Johnson, Matthew Stanley; Goodsite, Michael E.

    2008-01-01

    Theoretical chemistry involves explaining chemical phenomenon using natural laws. The primary tool of theoretical chemistry is quantum chemistry, and the field may be divided into electronic structure calculations, reaction dynamics and statistical mechanics. These three all play a role in...... addressing an issue of primary concern: understanding photochemical reaction rates at the various conditions found in the atmosphere. Atmospheric science includes both atmospheric chemistry and atmospheric physics, meteorology, climatology and the study of extraterrestrial atmospheres....

  3. 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...

  4. 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.

  5. Properties of daytime tweek atmospherics

    Czech Academy of Sciences Publication Activity Database

    Kolmašová, Ivana; Santolík, Ondřej; Lán, Radek; Uhlíř, Luděk

    Miltenberg: U.R.S.I. Landesausschuss in der Bundesrepublik Deutschland e.V, 2015. s. 53. [URSI Kleinheubacher Tagung 2015. 28.09.2005-30.09.2005, Miltenberg] Institutional support: RVO:68378289 Keywords : tweek atmospherics * ionospheric cutoff * ionosphere Subject RIV: DG - Athmosphere Sciences, Meteorology http://www.kh2015.de/KH2015_book_of_abstracts.pdf

  6. Atmospheric contamination during ultrasonic scaling

    NARCIS (Netherlands)

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

    2004-01-01

    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 treatmen

  7. Acoustics in the Martian Atmosphere

    Science.gov (United States)

    Williams, J.-P.

    2000-10-01

    With the advent of the first attempt to deliver an acoustic microphone to the Martian surface aboard the failed Mars Polar Lander, there has been growing interests in the development of acoustic sensors to compliment scientific payloads on future spacecraft. Terrestrial scientist have been very successful in using infrasound (sound at frequencies below human detection, detect and monitor atmospheric phenomena related to weather, tornadoes, mountain waves, microbaroms, ionospheric and auroral disturbances, and meteror/fireballs, as well as anthropogenic sources such as aircraft and nuclear explosions. Sounds on Mars at the audible frequencies (20 Hz to 20 kHz) will be severely attenuated due to viscous relaxation and thermal diffusion (collectively referred to as classical attenuation) which will be much more severe in the colder, less dense Martian atmosphere. Molecular relaxation of carbon dioxide will also contribute to the sound absorption in the lower audible frequencies. Since classical attenuation increases as a function of the frequency squared, at low infrasonic frequencies ( < 10 Hz), classical attenuation becomes less significant and sound absorption in the Martian atmosphere becomes more similar to that of the terrestrial atmosphere for the same frequencies. At these longer wavelengths, geometric spreading will dominate as the source of attenuation as the acoustic energy is spread out over an ever increasing spherical wave front. This implies that infrasound (10 to 0.01 Hz) will be a useful frequency range for future acoustic sensors developed for scientific payloads delivered to the Martian surface.

  8. Temporal Variations in Jupiter's Atmosphere

    Science.gov (United States)

    Simon-Miller, Amy A.; Chanover, N. J.; Yanamandra-Fisher, P.; Hammel, H. B.; dePater, I.; Noll, K.; Wong, M.; Clarke, J.; Sanchez-Levega, A.; Orton, G. S.; Gonzaga, S.

    2009-01-01

    In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.

  9. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis. PMID:20368458

  10. Positron production within our atmosphere

    Science.gov (United States)

    Dwyer, Joseph

    2016-04-01

    Positrons are commonly produced within our atmosphere by cosmic rays and the decay radioactive isotopes. Energetic positrons are also produced by pair production from the gamma rays generated by relativistic runaway electrons. Indeed, such positrons have been detected in Terrestrial Electron Beams (TEBs) in the inner magnetosphere by Fermi/GBM. In addition, positrons play an important role in relativistic feedback discharges (also known as dark lightning). Relativistic feedback models suggest that these discharges may be responsible for Terrestrial Gamma-ray Flashes (TGFs) and some gamma-ray glows. When producing TGFs, relativistic feedback discharges may generate large, lightning-like currents with current moments reaching hundreds of kA-km. In addition, relativistic feedback discharges also may limit the electric field that is possible in our atmosphere, affecting other mechanisms for generating runaway electrons. It is interesting that positrons, often thought of as exotic particles, may play an important role in thunderstorm processes. In this presentation, the role of positrons in high-energy atmospheric physics will be discussed. The unusual observation of positron clouds inside a thunderstorm by the ADELE instrument on an NCAR/NSF Gulfstream V aircraft will also be described. These observations illustrate that we still have much to learn about positron production within our atmosphere.

  11. Modelling land surface - atmosphere interactions

    DEFF Research Database (Denmark)

    Rasmussen, Søren Højmark

    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...

  12. Some advances in atmospheric chemistry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the recent decade, researches have been carried out by our group on some aspects of atmospheric chemistry through field observation, mechanism analysis and model simulation. Here some main results on greenhouse gas (CH4, N2O) emission from Chinese agricultural fields, aerosol, global carbon cycle and ozone variation in surface laver over China are briefly reported.

  13. 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…

  14. Forecasting global atmospheric CO2

    Directory of Open Access Journals (Sweden)

    A. Agustí-Panareda

    2014-05-01

    Full Text Available A new global atmospheric carbon dioxide (CO2 real-time forecast is now available as part of the pre-operational 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 CO2 forecasting system is that the land surface, including vegetation CO2 fluxes, is modelled online within the IFS. Other CO2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO2 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 CO2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO2 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 CO2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO2 fluxes also lead to accumulating errors in the CO2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO2 fluxes compared to total optimized fluxes and the atmospheric CO2 compared to observations. The largest biases in the atmospheric CO2 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 CO2 analyses based on the assimilation of CO2 satellite retrievals, as they

  15. 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.

  16. Ions in the Terrestrial Atmosphere and Other Solar System Atmospheres

    Science.gov (United States)

    Harrison, R. Giles; Tammet, Hannes

    2008-06-01

    Charged molecular clusters, traditionally called small ions, carry electric currents in atmospheres. Charged airborne particles, or aerosol ions, play an important role in generation and evolution of atmospheric aerosols. Growth of ions depends on the trace gas content, which is highly variable in the time and space. Even at sub-ppb concentrations, electrically active organic compounds ( e.g. pyridine derivatives) can affect the ion composition and size. The size and mobility are closely related, although the form of the relationship varies depending on the critical diameter, which, at 273 K, is about 1.6 nm. For ions smaller than this the separation of quantum levels exceeds the average thermal energy, allowing use of a molecular aggregate model for the size-mobility relation. For larger ions the size-mobility relation approaches the Stokes-Cunningham-Millikan law. The lifetime of a cluster ion in the terrestrial lower atmosphere is about one minute, determined by the balance between ion production rate, ion-ion recombination, and ion-aerosol attachment.

  17. Middle Atmosphere Electrodynamics (MAE). Middle atmospheric electrodynamics during MAP

    Science.gov (United States)

    Goldberg, R. A.

    1989-01-01

    The recent revival and strong motivation for research in middle atmospheric electrodynamics can be attributed, in large part, to the discovery of large (V/m) electric fields within the lower mesosphere during the decade prior to MAP. Subsequent rocket soundings appeared to verify the preliminary findings. During the MAP era, more sophisticated techniques have been employed to obtain measurements which respond positively to criticisms of earlier results, and which provide more insight regarding the character of the fields. The occurrence of mesospheric V/m electric fields now seems to require the presence of aerosols, of local winds and related dynamics, and of an atmospheric electrical conductivity less than 10(-10)S/m. Furthermore, new theoretical ideas describing the origin of the V/m fields are consistent with the measurements. The current status of results regarding V/m fields in the middle atmosphere is reviewed in light of the more widely accepted electric field structure for this region from rocket, balloon and modeling results.

  18. Atmosphere

    Science.gov (United States)

    Ghosh, D.; Mitra, S. K.

    2014-05-01

    This paper investigates the high-temperature corrosion behavior of microstructurally different regions of the weldment of 9 Cr-1 Mo steel used in thermal power plant boiler in SO2 + O2 environment. The weldment is produced by tungsten inert gas welding method, and the different regions of the weldment (weld metal, heat-affected zone, and base metal) are exposed in SO2 + O2 (ratio 2:1) environment at 973 K for 120 h. The reaction kinetics and corrosion growth rate of different regions of weldment in isothermal condition are evaluated. The post corroded scales of the different specimens are studied in SEM, EDS, and XRD. The results indicate that the weld metal shows higher corrosion rate followed by HAZ and base metal. The higher rate of corrosion of weldmetal is mainly attributed to the least protective inner scale of Cr2O3 with minimum Cr Content. This is due to the formation of delta ferrite, which leads to the precipitation of the Cr-based secondary phases and depletes the free Cr from the matrix. The thermal cycles during welding at high temperature are favorable for the formation of delta ferrite. On the other hand, in absence of delta ferrite, the base metal and HAZ regions of the weldment show lower corrosion rate than weld metal. The difference in corrosion rate in the three regions of the weldment is supplemented by post-corroded scale characterizations.

  19. High Vertically Resolved Atmospheric and Surface/Cloud Parameters Retrieved with Infrared Atmospheric Sounding Interferometer (IASI)

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, WIlliam L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

    2008-01-01

    The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25/cm and a spectral coverage from 645 to 2760/cm. Ultra-spectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. This physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the cloud-free and/or clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals are achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated indicating a high vertical structure of atmosphere is retrieved.

  20. 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

  1. Advances in Studies of the Middle and Upper Atmosphere and Their Coupling with the Lower Atmosphere

    Institute of Scientific and Technical Information of China (English)

    吕达仁; 易帆; 徐寄遥

    2004-01-01

    Recent advances in studies of the middle and upper atmosphere and their coupling with the lower atmosphere in China are briefly reviewed. This review emphasizes four aspects: (1) Development of instrumentation for middle and upper atmosphere observation; (2) Analyses and observation of middle and upper atmosphere; (3) Theoretical and modeling studies of planetary wave and gravity wave activities in the middle atmosphere and their relation to lower atmospheric processes; (4) Study on the coupling between the stratosphere and the troposphere.

  2. The atmospheric extinction of light

    CERN Document Server

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

    2015-01-01

    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.

  3. The atmospheric extinction of light

    Science.gov (United States)

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

    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.

  4. Domestic atmospheric pressure thermal deaerators

    Science.gov (United States)

    Egorov, P. V.; Gimmelberg, A. S.; Mikhailov, V. G.; Baeva, A. N.; Chuprakov, M. V.; Grigoriev, G. V.

    2016-04-01

    Based on many years of experience and proven technical solutions, modern atmospheric pressure deaerators of the capacity of 0.4 to 800 t/h were designed and developed. The construction of such deaerators is based on known and explored technical solutions. A two-stage deaeration scheme is applied where the first stage is a jet dripping level (in a column) and the second one is a bubble level (in a tank). In the design of deaeration columns, low-pressure hydraulic nozzles (Δ p TPP at heating and industrial-heating plants. The atmospheric pressure thermal deaerators developed at NPO TsKTI with consideration of the current requirements are recommended for the use in water preparation schemes of various power facilities.

  5. Atmospheric Scintillation in Astronomical Photometry

    CERN Document Server

    Osborn, J; Dhillon, V S; Wilson, R W

    2015-01-01

    Scintillation noise due to the Earth's turbulent atmosphere can be a dominant noise source in high-precision astronomical photometry when observing bright targets from the ground. Here we describe the phenomenon of scintillation from its physical origins to its effect on photometry. We show that Young's (1967) scintillation-noise approximation used by many astronomers tends to underestimate the median scintillation noise at several major observatories around the world. We show that using median atmospheric optical turbulence profiles, which are now available for most sites, provides a better estimate of the expected scintillation noise and that real-time turbulence profiles can be used to precisely characterise the scintillation noise component of contemporaneous photometric measurements. This will enable a better understanding and calibration of photometric noise sources and the effectiveness of scintillation correction techniques. We also provide new equations for calculating scintillation noise, including ...

  6. Juno's investigation of Jupiter's Atmosphere

    Science.gov (United States)

    Bolton, Scott

    The Juno mission is the second mission in NASA’s New Frontiers program. Launched in August 2011, Juno arrives at Jupiter in 2016 for a one year prime mission. Juno primary science goals include the study of Jupiter’s origin, interior structure, deep atmosphere, aurora and magnetosphere. Juno’s orbit around Jupiter is a polar elliptical orbit with perijove approximately 5000 km above the visible cloud tops. The payload consists of a set of microwave antennas for deep sounding, magnetometers, gravity radio science, low and high energy charged particle detectors, electric and magnetic field radio and plasma wave experiment, ultraviolet imaging spectrograph, infrared imager/spectrometer and a visible camera. An overview of Juno's investigation of Jupiter and its atmosphere will be presented.

  7. Climate of the upper atmosphere

    OpenAIRE

    Christoph Jacobi; Giorgiana De Franceschi; Dalia Buresˇová; Pal Bencze; David Altadill; Andrei V. Mikhailov; Jan Lasˇtovicˇka; Jürgen Bremer; Stamatis Kouris; Loredana Perrone; Esa Turunen

    2009-01-01

    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...

  8. 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, a...... 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....

  9. 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.

  10. Instrumentation for atmospheric ion measurements

    CERN Document Server

    Aplin, K L

    2005-01-01

    Small ions are part of the atmospheric aerosol spectrum, and study of ion-aerosol interactions is fundamental in atmospheric physics. Air ion physics and instrumentation are reviewed, including the historical context. A miniaturised Gerdien condenser for ion measurement, operating in situ to minimise inlet errors, is described. Two operating modes using independent current and voltage decay measurements are employed. A more sophisticated self-calibrating and fully programmable ion mobility spectrometer (PIMS) based on the same principles, is also discussed. Detailed analysis of error terms and application of new technology is demonstrated to greatly improve its capability. Self-consistent experimental approaches, including ionisation and ion concentration instruments, are used for calibration. In developing and characterising the individual components of the PIMS, favourable and unfavourable operating regimes are identified: this approach can also be applied to other aspiration ion counting techniques. Use of...

  11. Modeling of atmospheric pollutant transfers

    International Nuclear Information System (INIS)

    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.)

  12. Atmospheric Radiation Measurement Program plan

    International Nuclear Information System (INIS)

    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. Electrical and optical properties of thin indium tin oxide films produced by pulsed laser ablation in oxygen or rare gas atmospheres

    DEFF Research Database (Denmark)

    Thestrup, B.; Schou, Jørgen; Nordskov, A.;

    1999-01-01

    Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate temperatu......Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate...

  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. Lightning detection in planetary atmospheres

    CERN Document Server

    Aplin, Karen L

    2016-01-01

    Lightning in planetary atmospheres is now a well-established concept. Here we discuss the available detection techniques for, and observations of, planetary lightning by spacecraft, planetary landers and, increasingly, sophisticated terrestrial radio telescopes. Future space missions carrying lightning-related instrumentation are also summarised, specifically the European ExoMars mission and Japanese Akatsuki mission to Venus, which could both yield lightning observations in 2016.

  16. Cumulant expansions for atmospheric flows

    Science.gov (United States)

    Ait-Chaalal, Farid; Schneider, Tapio; Meyer, Bettina; Marston, J. B.

    2016-02-01

    Atmospheric flows are governed by the equations of fluid dynamics. These equations are nonlinear, and consequently the hierarchy of cumulant equations is not closed. But because atmospheric flows are inhomogeneous and anisotropic, the nonlinearity may manifest itself only weakly through interactions of nontrivial mean fields with disturbances such as thermals or eddies. In such situations, truncations of the hierarchy of cumulant equations hold promise as a closure strategy. Here we show how truncations at second order can be used to model and elucidate the dynamics of turbulent atmospheric flows. Two examples are considered. First, we study the growth of a dry convective boundary layer, which is heated from below, leading to turbulent upward energy transport and growth of the boundary layer. We demonstrate that a quasilinear truncation of the equations of motion, in which interactions of disturbances among each other are neglected but interactions with mean fields are taken into account, can capture the growth of the convective boundary layer. However, it does not capture important turbulent transport terms in the turbulence kinetic energy budget. Second, we study the evolution of two-dimensional large-scale waves, which are representative of waves seen in Earth's upper atmosphere. We demonstrate that a cumulant expansion truncated at second order (CE2) can capture the evolution of such waves and their nonlinear interaction with the mean flow in some circumstances, for example, when the wave amplitude is small enough or the planetary rotation rate is large enough. However, CE2 fails to capture the flow evolution when strongly nonlinear eddy-eddy interactions that generate small-scale filaments in surf zones around critical layers become important. Higher-order closures can capture these missing interactions. The results point to new ways in which the dynamics of turbulent boundary layers may be represented in climate models, and they illustrate different classes

  17. Atmospheric Circulation of Terrestrial Exoplanets

    OpenAIRE

    Showman, Adam P.; Wordsworth, Robin D.; Merlis, Timothy M.; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical a...

  18. Terrestrial atmosphere, water and astrobiology

    OpenAIRE

    Coradini M.; Brack A.

    2010-01-01

    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 bon...

  19. Atmospheric chemistry in volcanic plumes

    OpenAIRE

    von Glasow, Roland

    2010-01-01

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume...

  20. Light extinction in the atmosphere

    International Nuclear Information System (INIS)

    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

  1. Light extinction in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    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. Equipment selection for atmospheric drying

    International Nuclear Information System (INIS)

    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 D2O vapour recovery system, and highlights advances in dryer technology. (author)

  3. Potential biomonitors for atmospheric pollution

    International Nuclear Information System (INIS)

    Undesirable influence of air pollution on the human health and the ecosystem has led to an increased interest in toxic emission monitoring programs. To fingerprint the countrywide and regional transboundary pollution profiles, extensive direct monitoring network is needed, which is very expensive and laborious. Plant leaves. Mosses and epiphytic lichens are regarded as potential alternate tools for monitoring levels of atmospheric pollution. Mosses and epiphytic lichens, unlike higher plants have no roots and waxy cuticle nor stomata; hence for mineral nutrition they are largely dependent on wet or dry deposition from the atmosphere. This unique feature has been exploited to predict the pollution levels of the areas in which they are grown by analyzing the embodied toxic elements. Sampling of such naturally growing bioindicators is relatively easier and no sophisticated equipment are needed. The aim of this study was to obtain insight into the response of such plants, when exposed in the vicinity of highly polluted areas and subsequently to confirm the agreement between elemental levels in bioindicators and those measured in atmospheric deposition collected directly with air samplers. INAA and AAS techniques were employed for multielement analysis of exposed samples. Definite influence of pollution on the studied bioindicators was observed for some of the heavy metals like Cd, Cu, Pb and Zn. Results obtained in this work indicate the feasibility of using Broussonetia Papyrifera levels and moss as bioindicators for environmental pollution monitoring. This pattern was also confirmed by analyzing the air particulate matters (APM) collected on filters using Gent air sampler. (author)

  4. Atmospheric Downscaling using Genetic Programming

    Science.gov (United States)

    Zerenner, Tanja; Venema, Victor; Simmer, Clemens

    2013-04-01

    Coupling models for the different components of the Soil-Vegetation-Atmosphere-System requires up-and downscaling procedures. Subject of our work is the downscaling scheme used to derive high resolution forcing data for land-surface and subsurface models from coarser atmospheric model output. The current downscaling scheme [Schomburg et. al. 2010, 2012] combines a bi-quadratic spline interpolation, deterministic rules and autoregressive noise. For the development of the scheme, training and validation data sets have been created by carrying out high-resolution runs of the atmospheric model. The deterministic rules in this scheme are partly based on known physical relations and partly determined by an automated search for linear relationships between the high resolution fields of the atmospheric model output and high resolution data on surface characteristics. Up to now deterministic rules are available for downscaling surface pressure and partially, depending on the prevailing weather conditions, for near surface temperature and radiation. Aim of our work is to improve those rules and to find deterministic rules for the remaining variables, which require downscaling, e.g. precipitation or near surface specifc humidity. To accomplish that, we broaden the search by allowing for interdependencies between different atmospheric parameters, non-linear relations, non-local and time-lagged relations. To cope with the vast number of possible solutions, we use genetic programming, a method from machine learning, which is based on the principles of natural evolution. We are currently working with GPLAB, a Genetic Programming toolbox for Matlab. At first we have tested the GP system to retrieve the known physical rule for downscaling surface pressure, i.e. the hydrostatic equation, from our training data. We have found this to be a simple task to the GP system. Furthermore we have improved accuracy and efficiency of the GP solution by implementing constant variation and

  5. Radiative equilibrium and escape of Pluto's atmosphere

    Science.gov (United States)

    Erwin, Justin; Koskinen, Tommi T.; Yelle, Roger V.

    2015-11-01

    Observations of Pluto’s extend atmosphere by the New Horizons spacecraft motivate an update to our modeling effort on Pluto’s atmosphere. New Horizons observations have already improved our constraints on planet radius and surface pressure, which are key to modeling the atmospheric structure. We model the radiative conductive equilibrium in the lower atmosphere combined with the UV driven escape model of the upper atmosphere. The non-LTE radiative transfer model in the lower atmosphere include heating and cooling by CH4, CO, and HCN. The escape model of the upper atmosphere is updated to include diffusion and escape of each molecular component. These results will be used to aid in the analysis and better understanding of the full atmospheric structure.

  6. 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...

  7. 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.

  8. International Comprehensive Ocean Atmosphere Data Set (ICOADS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — International Comprehensive Ocean Atmosphere Data Set (ICOADS) consists of digital data set DSI-1173, archived at the National Climatic Data Center (NCDC). ICOADS...

  9. Internal wave coupling processes in Earth's atmosphere

    CERN Document Server

    Yiğit, Erdal

    2014-01-01

    This paper presents a contemporary review of vertical coupling in the atmosphere and ionosphere system induced by internal waves of lower atmospheric origin. Atmospheric waves are primarily generated by meteorological processes, possess a broad range of spatial and temporal scales, and can propagate to the upper atmosphere. A brief summary of internal wave theory is given, focusing on gravity waves, solar tides, planetary Rossby and Kelvin waves. Observations of wave signatures in the upper atmosphere, their relationship with the direct propagation of waves into the upper atmosphere, dynamical and thermal impacts as well as concepts, approaches, and numerical modeling techniques are outlined. Recent progress in studies of sudden stratospheric warming and upper atmospheric variability are discussed in the context of wave-induced vertical coupling between the lower and upper atmosphere.

  10. Atmospheric electrification in the Solar System

    CERN Document Server

    Aplin, K

    2005-01-01

    Atmospheric electrification is not a purely terrestrial phenomenon: all Solar System planetary atmospheres become slightly electrified by cosmic ray ionisation. There is evidence for lightning on Jupiter, Saturn, Uranus and Neptune, and it appears likely to exist on Mars, Venus and Titan. Atmospheric electricity has controversially been implicated in climate on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This paper reviews planetary atmospheric electricity including ionisation and ion-aerosol interactions. The conditions necessary for a global electric circuit, and the likelihood of meeting these conditions in other planetary atmospheres are briefly discussed. Atmospheric electrification could be important throughout the Solar System, particularly at the outer planets which receive little solar radiation, increasing the significance of electrical forces. Nucleation onto atmospheric ions has been predicted to affect ...

  11. Quantitative determination of atmospheric hydroperoxyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Springston, Stephen R. (Upton, NY); Lloyd, Judith (Westbury, NY); Zheng, Jun (Stony Brook, NY)

    2007-10-23

    A method for the quantitative determination of atmospheric hydroperoxyl radical comprising: (a) contacting a liquid phase atmospheric sample with a chemiluminescent compound which luminesces on contact with hydroperoxyl radical; (b) determining luminescence intensity from the liquid phase atmospheric sample; and (c) comparing said luminescence intensity from the liquid phase atmospheric sample to a standard luminescence intensity for hydroperoxyl radical. An apparatus for automating the method is also included.

  12. Radar range measurements in the atmosphere.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2013-02-01

    The earth's atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

  13. A Search for Magnesium in Europa's Atmosphere

    OpenAIRE

    Horst, Sarah M.; Brown, Michael 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 wa...

  14. 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

  15. Dynamics of Jupiter’s atmosphere

    OpenAIRE

    Ingersoll, Andrew P.; Dowling, Timothy E.; Gierasch, Peter J.; Orton, Glenn S.; Read, Peter L.; Sánchez-Lavega, Agustin; Showman, Adam P.; Simon-Miller, Amy A.; Vasavada, Ashwin R.

    2004-01-01

    Giant planet atmospheres provided many of the surprises and remarkable discoveries of planetary exploration during the past few decades. Studying Jupiter's atmosphere and comparing it with Earth's gives us critical insight and a broad understanding of how atmospheres work that could not be obtained by studying Earth alone.

  16. Hypothesis on the nature of atmospheric UFOs

    Science.gov (United States)

    Mukharev, L. A.

    1991-08-01

    A hypothesis is developed according to which the atmospheric UFO phenomenon has an electromagnetic nature. It is suggested that an atmospheric UFO is an agglomeration of charged atmospheric dust within which there exists a slowly damped electromagnetic field. This field is considered to be the source of the observed optical effects and the motive force of the UFO.

  17. Atmospheric Methane Contributions From Fractured Bedrock Aquifers

    Science.gov (United States)

    Marrin, D. L.

    2013-05-01

    Groundwater is not normally considered as an important contributor of atmospheric methane because the organic carbon content of aquifers is too low to sustain significant methanogenesis. Also, groundwater-generated methane partitions into the gas phase of the overlying soil, where it either dissolves in the pore water or is oxidized to carbon dioxide by methanotrophs. There are, however, localized conditions (related to human activities and hydrogeologic conditions) under which atmospheric contributions of groundwater-generated methane occur at the ground surface. Storing and transporting liquid petroleum products in the subsurface has resulted in the local introduction of high concentrations of degradable organic carbon and the creation of redox conditions that favor methanogenesis over more oxidative biodegradation pathways. Groundwater overlain by fractured bedrock, rather than by unconsolidated porous media, creates a situation where CH4 migrates through discrete fractures, thus limiting the soil volume and the surface area available for methanotrophic activity. The spatial distribution of methane in thin surface soils overlying bedrock suggests that CH4 migrates via fracture networks and that CH4 oxidation is a factor of about 50 less than that measured in typical unconsolidated soils. Atmospheric flux rates associated with contaminated bedrock aquifers were on the order of several grams of carbon (as CH4) per square meter, which is less than that reported for well documented sources (e.g., rice paddies) and probably represents a minor worldwide contribution. Nonetheless, these aquifers can represent an important localized source, can shift soils from a sink to a source of methane, and can permit petroleum products to load carbon (as biogenic CH4 and CO2) to the atmosphere without ever being combusted.

  18. Currents in the cometary atmosphere

    Science.gov (United States)

    Ip, W.-H.

    1979-01-01

    If the structure of the magnetic field and electric current in the cometary type I tail can be represented by an electric current circuit, disruption of the cross-tail current system may lead to a current discharging through the cometary ionosphere, and the dissipation of the magnetic energy stored in the tail. From the point of view of energy budget, a tail-aligned magnetic field on the order of 10 gamma will be sufficient to produce a strong ionization effect of the cometary atmosphere.

  19. Therapeutic potential of atmospheric neutrons

    International Nuclear Information System (INIS)

    Background: Glioblastoma multiform (GBM) is the most common and most aggressive type of primary brain tumour in humans. It has a very poor prognosis despite multi-modality treatments consisting of open craniotomy with surgical resection, followed by chemotherapy and/or radiotherapy. Recently, a new treatment has been proposed - Boron Neutron Capture Therapy (BNCT) - which exploits the interaction between Boron-10 atoms (introduced by vector molecules) and low energy neutrons produced by giant accelerators or nuclear reactors. Methods: The objective of the present study is to compute the deposited dose using a natural source of neutrons (atmospheric neutrons). For this purpose, Monte Carlo computer simulations were carried out to estimate the dosimetric effects of a natural source of neutrons in the matter, to establish if atmospheric neutrons interact with vector molecules containing Boron-10. Results: The doses produced (an average of 1 micro Gy in a 1 g tumour) are not sufficient for therapeutic treatment of in situ tumours. However, the non-localised yet specific dosimetric properties of 10B vector molecules could prove interesting for the treatment of micro-metastases or as (neo)adjuvant treatment. On a cellular scale, the deposited dose is approximately 0.5 Gy/neutron impact. Conclusion: It has been shown that BNCT may be used with a natural source of neutrons, and may potentially be useful for the treatment of micro-metastases. The atmospheric neutron flux is much lower than that utilized during standard NBCT. However the purpose of the proposed study is not to replace the ordinary NBCT but to test if naturally occurring atmospheric neutrons, considered to be an ionizing pollution at the Earths surface, can be used in the treatment of a disease such as cancer. To finalize this study, it is necessary to quantify the biological effects of the physically deposited dose, taking into account the characteristics of the incident particles (alpha particle and Lithium

  20. Evolution of the Martian atmosphere

    Science.gov (United States)

    Pepin, R. O.

    Evolution of Mars' noble gases through two stages of hydrodynamic escape early in planetary history has been proposed previously by the author. In the first evolutionary stage of this earlier model, beginning at a solar age of approximately 50 m.y., fractionating escape of a H2-rich primordial atmosphere containing CO2, N2, and the noble gases in roughly the proportions found in primitive carbonaceous (CI) chondrites is driven by intense extreme-ultraviolet (EUV) leads to a long (approximately 80 m.y.) period of quiescence, followed by an abrupt degassing of remnant H2, CO2, and N2 from the mantle and of solar-composition noble gases lighter than Xe from the planet's volatile-rich accretional core. Degassed H refuels hydrodynamic loss in a waning but still potent solar EUV flux. Atmospheric Xe, Kr, and Ar remaining at the end of this second escape stage, approximately 4.2 G.y. ago, have evolved to their present-day abundances and compositions. Residual Ne continues to be modified by accretion of solar wind gases throughout the later history of the planet. This model does not address a number of processes that now appear germane to Martian atmospheric history. One, gas loss and fractionation by sputtering, has recently been shown to be relevant. Another, atmospheric erosion, appears increasingly important. In the absence then of a plausible mechanism, the model did not consider the possibility of isotopic evolution of noble gases heavier than Ne after the termination of hydrodynamic escape. Subsequent non-thermal loss of N was assumed, in an unspecified way, to account for the elevation of N from the model value of approximately 250 percent at the end of the second escape stage to approximately 620 percent today. Only qualitative attention was paid to the eroding effects of impact on abundances of all atmophilic species prior to the end of heavy bombardment approximately 3.8 G.y. ago. No attempt was made to include precipitation and recycling of carbonates in

  1. Low-energy atmospheric neutrinos

    International Nuclear Information System (INIS)

    Results of a three-dimensional Monte Carlo calculation of the low-energy spectrum and angular distribution of atmospheric neutrinos are presented and compared with earlier one-dimensional calculations valid at higher neutrino energies. The three-dimensional results agree with the one-dimensional calculation above 200 MeV, but are up to a factor of 2 lower below 50 MeV. Geomagnetic-cutoff effects on primary cosmic rays significantly reduce the neutrino flux at low geomagnetic latitudes. Azimuthal angular dependence shows a strong north-south asymmetry for upward-going fluxes, whereas an east-west effect is apparent only at low geomagnetic latitudes

  2. Evolution of the Earth's Atmosphere.

    Science.gov (United States)

    Rasool, S I

    1967-09-22

    We living things are a late outgrowth of the metabolism of our Galaxy. The carbon that enters so importantly into our composition was cooked in the remote past in a dying star. From it at lower temperatures nitrogen and oxygen were formed. These, our indispensable elements, were spewed out into space in the exhalations of red giants and such stellar catastrophes as supernovae, there to be mixed with hydrogen, to form eventually the substance of the sun and planets, and ourselves. The waters of ancient seas set the pattern of ions in our blood. The ancient atmospheres molded our metabolism. PMID:17819549

  3. Chemical characterization of atmospheric particles

    International Nuclear Information System (INIS)

    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)

  4. Hadrons produced in atmospheric interactions

    International Nuclear Information System (INIS)

    Systematic analysis is made on cosmic ray induced atmospheric interactions detected to study the hadron multiple production. It is demonstrated that hadrons rich events are not characterized only by super families (halo events). About 5% of the events with visible energy in the range of 100-1000 TeV and transverse momentum sensity over the rapidity scale ≥1 GeV.km, has an anomalously 'hadron excess', already observed in super families (visible energy > 1000 TeV). The analysis did not include events identified as exotic ones (Centauro, Mini Centauro, Geminion and Chiron). (Author)

  5. Carbon in Atmospheric Particulate Matter

    International Nuclear Information System (INIS)

    Carbon compounds account for a large fraction of airborne particulate matter ('carbonaceous aerosols'). Their presence raises a number of scientific questions dealing with climate issues and possible effects on human health. This review describes the current state of knowledge with respect to the ambient concentrations levels (elemental carbon, organic carbon and organic matter) and the various emission sources, and summarizes the role of atmospheric carbon in the various environmental issues. The report finishes by identifying the actual gaps in knowledge and gives (related) suggestions for future research

  6. Earth’s Earliest Atmospheres

    OpenAIRE

    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 s...

  7. 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.

  8. Does Pluto have a substantial atmosphere

    International Nuclear Information System (INIS)

    The presence of CH4 ice on Pluto implies that Pluto may have a substantial atmosphere consisting of heavy gases. Without such an atmosphere, sublimation of the CH4 ice would be so rapid on a cosmogonic time scale that either such an atmosphere would soon develop through the exposure of gases trapped in the CH4 ice or else the surface CH4 ice would soon be all sublimated away as other, more stable, ices became exposed. If such stable ices were present from the beginning, the existence of CH4 frosts would also imply that Pluto's present atmosphere contains a remnant of its primordial atmosphere

  9. The Earth's atmosphere its physics and dynamics

    CERN Document Server

    Saha, Kshudiram

    2008-01-01

    The book entitled ""Atmospheric science and Global Warming"" covers a wide area of the atmospheric science, focusing particularly on those physical and dynamical aspects of our environment which tend to create heat sources and sinks in the earth-atmosphere system and which it seeks to balance through circulation at different time and space scales. The processes of heat transfer in the atmosphere and ocean by general circulation and by waves and oscillations are discussed in detail. The heat balance of the atmosphere is discussed after taking into consideration the role of various types of gree

  10. The atmosphere and ocean: A physical introduction

    International Nuclear Information System (INIS)

    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 sciences annual progress report, 1974

    International Nuclear Information System (INIS)

    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

  12. Atmospheres of Hot Super-Earths

    CERN Document Server

    Castan, Thibaut

    2011-01-01

    Hot super-Earths likely possess minimal atmospheres established through vapor saturation equilibrium with the ground. We solve the hydrodynamics of these tenuous atmospheres at the surface of Corot-7b, Kepler 10b and 55 Cnc-e, including idealized treatments of magnetic drag and ohmic dissipation. We find that atmospheric pressures remain close to their local saturation values in all cases. Despite the emergence of strongly supersonic winds which carry sublimating mass away from the substellar point, the atmospheres do not extend much beyond the day-night terminators. Ground temperatures, which determine the planetary thermal (infrared) signature, are largely unaffected by exchanges with the atmosphere and thus follow the effective irradiation pattern. Atmospheric temperatures, however, which control cloud condensation and thus albedo properties, can deviate substantially from the irradiation pattern. Magnetic drag and ohmic dissipation can also strongly impact the atmospheric behavior, depending on atmospheri...

  13. Waves in vertically inhomogeneous dissipative atmosphere

    CERN Document Server

    Dmitrienko, I S

    2015-01-01

    A method of construction of solution for acoustic-gravity waves (AGW) above a wave source, taking dissipation throughout the atmosphere into account (Dissipative Solution above Source, DSAS), is proposed. The method is to combine three solutions for three parts of the atmosphere: an analytical solution for the upper isothermal part and numerical solutions for the real non-isothermal dissipative atmosphere in the middle part and for the real non-isothermal small dissipation atmosphere in the lower one. In this paper the method has been carried out for the atmosphere with thermal conductivity but without viscosity. The heights of strong dissipation and the total absorption index in the regions of weak and average dissipation are found. For internal gravity waves the results of test calculations for an isothermal atmosphere and calculations for a real non-isothermal atmosphere are shown in graphical form. An algorithm and appropriate code to calculate DSAS, taking dissipation due to finite thermal conductivity i...

  14. Escape and Stand of the Pluto Atmosphere

    Institute of Scientific and Technical Information of China (English)

    GAO Chong-Yi

    2002-01-01

    Molar mass μmin of the lightest gas, which will exist "forever" in the atmosphere at the planet surface,can be evaluated by Jeans rule. The μmin of Pluto is 17.3 g@ mol-1. It is evident that both N2 and CO can be major atmospheric composition at the Pluto surface, and will exist "forever". CH4 can only be escaping slowly from Pluto atmosphere, and still holds quite a proportion in current Pluto atmosphere. However, it will not escape from Titan (or Jupiter, Saturn) atmosphere largely, and will exist "forever". Given the quantitylevelof partial pressure of CH4 in Pluto and Titan (or Jupiter, Saturn) original atmosphere is the same, it will be clear that the current partial pressure of CH4 in Pluto surface atmosphere is 10-3 Pa.

  15. Substrate selection for optimum qualitative and quantitative single atmospheric particles analysis using nano-manipulation, sequential thin-window electron probe X-ray microanalysis and micro-Raman spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Godoi, Ricardo Henrique Moreton [Graduate Program in Environmental Management, Centro Universitario Positivo-UnicenP R., Prof. Pedro Viriato Parigot de Souza, 5300, Campo Comprido, Curitiba-PR-CEP 81280-330 (Brazil); School of Chemistry, University of the Witwatersrand, Private Bag X 3, Wits, 2050 (South Africa); Potgieter-Vermaak, Sanja [Graduate Program in Environmental Management, Centro Universitario Positivo-UnicenP R., Prof. Pedro Viriato Parigot de Souza, 5300, Campo Comprido, Curitiba-PR-CEP 81280-330 (Brazil) and School of Chemistry, University of the Witwatersrand, Private Bag X 3, Wits, 2050 (South Africa)]. E-mail: sanja.potgieter@ua.ac.be; Hoog, Johan de [Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Kaegi, Ralf [EMPA, Swiss Federal Laboratories for Materials Testing and Research, Ueberlandstrasse 129, Dubendorf, CH-8600 (Switzerland); Grieken, Rene van [Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium)

    2006-04-15

    Sequential electron probe X-ray microanalysis using thin-window energy dispersive X-ray detection (TW-EDX-EPMA) and micro-Raman spectrometry (MRS) on the same atmospheric particle using nano-manipulation, is demonstrated. The advantageous combination of these two techniques allows information on the morphology, size, elemental and molecular composition, as well as the molecular structure of the same individual particle with a diameter as small as 500 nm. The use of an ultra-thin atmospheric window and a cold stage in EPMA enables qualitative and quantitative analysis of low-Z elements like C, N, and O as well as higher-Z elements. The work illustrates substrate optimisation and subsequent application in the analysis of atmospheric particles. Particle relocation was achieved by manipulative transfer onto transmission electron microscope grids, in an environmental scanning electron microscope, using 100 nm glass tips. A moderate correlation between the elemental composition obtained by TW-EDX-EPMA and the molecular fingerprint obtained by MRS is illustrated and its useful application in the interpretation of indoor air quality is discussed.

  16. 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

  17. ADVANCES ON STUDY OF MIDDLE AND UPPER ATMOSPHERE AND THEIR COUPLING WITH LOWER ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper advances on study of middle and upper atmosphere and their cou pling with lower atmosphere in China in recent two years are briefly reviewed.This review emphasized three aspects, ie. (1) analysis and observation of mid and upper atmosphere over China; (2) theoretical and modelling study of grav ity wave activities in middle atmosphere and their relation to lower atmospheric processes; (3) coupling between the stratosphere and troposphere.

  18. Dust ablation in Pluto's atmosphere

    Science.gov (United States)

    Horanyi, Mihaly; Poppe, Andrew; Sternovsky, Zoltan

    2016-04-01

    Based on measurements by dust detectors onboard the Pioneer 10/11 and New Horizons spacecraft the total production rate of dust particles born in the Edgeworth Kuiper Belt (EKB) has been be estimated to be on the order of 5 ṡ 103 kg/s in the approximate size range of 1 - 10 μm. Dust particles are produced by collisions between EKB objects and their bombardment by both interplanetary and interstellar dust particles. Dust particles of EKB origin, in general, migrate towards the Sun due to Poynting-Robertson drag but their distributions are further sculpted by mean-motion resonances as they first approach the orbit of Neptune and later the other planets, as well as mutual collisions. Subsequently, Jupiter will eject the vast majority of them before they reach the inner solar system. The expected mass influx into Pluto atmosphere is on the order of 200 kg/day, and the arrival speed of the incoming particles is on the order of 3 - 4 km/s. We have followed the ablation history as function of speed and size of dust particles in Pluto's atmosphere, and found that volatile rich particles can fully sublimate due to drag heating and deposit their mass in narrow layers. This deposition might promote the formation of the haze layers observed by the New Horizons spacecraft. This talk will explore the constraints on the composition of the dust particles by comparing the altitude of the deposition layers to the observed haze layers.

  19. Kuiper Prize: Giant Planet Atmospheres

    Science.gov (United States)

    Ingersoll, Andrew P.

    2007-10-01

    The study of giant planet atmospheres is near and dear to me, for several reasons. First, the giant planets are photogenic; the colored clouds are great tracers, and one can make fantastic movies of the atmosphere in motion. Second, the giant planets challenge us with storms that last for hundreds of years and winds that blow faster the farther you go from the sun. Third, they remind us of Earth with their hurricanes, auroras, and lightning, but they also are the link to the 200 giant planets that have been discovered around other stars. This talk will cover the past, present, and future (one hopes) of giant planet research. I will review the surprises of the Voyager and Galileo eras, and will discuss what we are learning now from the Cassini orbiter. I will review the prospects for answering the outstanding questions like: Where's the water? What is providing the colors of the clouds? How deep do the features extend? Where do the winds get their energy? What is the role of the magnetic field? Finally, I will briefly discuss how extrasolar giant planets compare with objects in our own solar system.

  20. High-energy atmospheric neutrinos

    CERN Document Server

    Sinegovsky, S I; Sinegovskaya, T S

    2010-01-01

    High-energy neutrinos, arising from decays of mesons that were produced through the cosmic rays collisions with air nuclei, form unavoidable background noise in the astrophysical neutrino detection problem. The atmospheric neutrino flux above 1 PeV should be supposedly dominated by the contribution of charmed particle decays. These (prompt) neutrinos originated from decays of massive and shortlived particles, $D^\\pm$, $D^0$, $\\bar{D}{}^0$, $D_s^\\pm$, $\\Lambda^+_c$, form the most uncertain fraction of the high-energy atmospheric neutrino flux because of poor explored processes of the charm production. Besides, an ambiguity in high-energy behavior of pion and especially kaon production cross sections for nucleon-nucleus collisions may affect essentially the calculated neutrino flux. There is the energy region where above flux uncertainties superimpose. A new calculation presented here reveals sizable differences, up to the factor of 1.8 above 1 TeV, in muon neutrino flux predictions obtained with usage of known...

  1. Atmospheric discharges and particle fluxes

    Science.gov (United States)

    Chilingarian, A.; Chilingaryan, S.; Reymers, A.

    2015-07-01

    Fluxes of the electrons, gamma rays, and neutrons observed by particle detectors located on the Earth's surface during thunderstorms originate so-called Thunderstorm Ground Enhancements (TGEs). The relativistic runaway electron avalanches giving rise to TGEs originate in the thundercloud's lower dipole between the main negatively charged region in the middle of the thundercloud and transient lower positively charged region. Acceleration of electrons in the upper dipole between main negative and main positive charge regions leads to initiation of the terrestrial gamma flashes (TGFs) intensive researched during the last two decades by orbiting gamma ray observatories. TGFs are exceptionally intense, submillisecond bursts of electromagnetic radiation directed to the open space from the thunderstorm atmosphere. Unlike visible lightning, TGF beams do not create a hot plasma channel and optical flash; hence, in the literature they got name "dark lightning." We investigate the TGEs development in 1 min and 1 s time series of particle detector count rates. Synchronized time series of the near-surface electric field and lightning occurrences allows interconnecting two atmospheric phenomena. Registration of the Extensive Air Showers allows approaching problems of relation of the lightning occurrences and particle fluxes.

  2. Thermal structure of Uranus' atmosphere.

    Science.gov (United States)

    Marley, M S; McKay, C P

    1999-04-01

    Application of a radiative-convective equilibrium model to the thermal structure of Uranus' atmosphere evaluates the role of hazes in the planet's stratospheric energy budget and places a lower limit on the internal energy flux. The model is constrained by Voyager and post-Voyager observations of the vertical aerosol and radiative active gas profiles. Our baseline model generally reproduces the observed tropospheric and stratospheric temperature profile. However, as in past studies, the model stratosphere from about 10(-3) to 10(-1) bar is too cold. We find that the observed stratospheric hazes do not warm this region appreciably and that any postulated hazes capable of warming the stratosphere sufficiently are inconsistent with Voyager and ground-based constraints. We explore the roles played by the stratospheric methane abundance, the H2 pressure-induced opacity, photochemical hazes, and C2H2, and C2H6 in controlling the temperature structure in this region. Assuming a vertical methane abundance profile consistent with that found by the Voyager UVS occultation observations, the model upper stratosphere, from 10 to 100 microbar, is also too cold. Radiation in the 7.8-micrometers band from a small abundance of hot methane in the lower thermosphere absorbed in this region can warm the atmosphere and bring models into closer agreement with observations. Finally, we find that internal heat fluxes < or approximately 60 erg cm-2 sec-1 are inconsistent with the observed tropospheric temperature profile. PMID:11542927

  3. Pulling Results Out of Thin Air: Four Years of Ozone and Greenhouse Gas Measurements by the Alpha Jet Atmospheric Experiment (AJAX)

    Science.gov (United States)

    Yates, Emma

    2015-01-01

    The Alpha Jet Atmospheric eXperiment (AJAX) has been measuring atmospheric ozone, carbon dioxide, methane and meteorological parameters from near the surface to 8000 m since January 2011. The main goals are to study photochemical ozone production and the impacts of extreme events on western US air quality, provide data to support satellite observations and aid in the quantification of emission sources e.g. wildfires, urban outflow, diary and oil and gas. The aircraft is based at Moffett Field and flies multiple times a month to sample vertical profiles at selected sites in California and Nevada, providing long-term data records at these sites. AJAX is also uniquely positioned to launch with short notice sampling flights in rapid response to extreme events e.g. the 2013 Yosemite Rim fire. This talk will focus on the impacts of vertical transport on surface air quality, and investigation of emission sources from diaries and wildfires.

  4. Global Daily Atmospheric State Profiles from the Atmospheric Infrared Sounder

    Science.gov (United States)

    Pagano, Thomas S.; Aumann, Hartmut H.; Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Chahine, Moustafa T.

    2008-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 (micro)m to 15.4 (micro)m and a 13.5 km footprint. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles, clouds, dust and trace gas amounts for CO2, CO, SO2, O3 and CH4.[1] AIRS data are used for weather forecasting and studies of global climate change. The AIRS is a 'facility' instrument developed by NASA as an experimental demonstration of advanced technology for remote sensing and the benefits of high resolution infrared spectra to science investigations.

  5. RADIATION HYDRODYNAMICS OF HOT JUPITER ATMOSPHERES

    International Nuclear Information System (INIS)

    Radiative transfer in planetary atmospheres is usually treated in the static limit, i.e., neglecting atmospheric motions. We argue that hot Jupiter atmospheres, with possibly fast (sonic) wind speeds, may require a more strongly coupled treatment, formally in the regime of radiation hydrodynamics. To lowest order in v/c, relativistic Doppler shifts distort line profiles along optical paths with finite wind velocity gradients. This leads to flow-dependent deviations in the effective emission and absorption properties of the atmospheric medium. Evaluating the overall impact of these distortions on the radiative structure of a dynamic atmosphere is non-trivial. We present transmissivity and systematic equivalent width excess calculations which suggest possibly important consequences for radiation transport in hot Jupiter atmospheres. If winds are fast and bulk Doppler shifts are indeed important for the global radiative balance, accurate modeling and reliable data interpretation for hot Jupiter atmospheres may prove challenging: it would involve anisotropic and dynamic radiative transfer in a coupled radiation-hydrodynamical flow. On the bright side, it would also imply that the emergent properties of hot Jupiter atmospheres are more direct tracers of their atmospheric flows than is the case for solar system planets. Radiation hydrodynamics may also influence radiative transfer in other classes of hot exoplanetary atmospheres with fast winds.

  6. 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

  7. Intermediate ions in the atmosphere

    Science.gov (United States)

    Tammet, Hannes; Komsaare, Kaupo; Hõrrak, Urmas

    2014-01-01

    Intermediate air ions are charged nanometer-sized aerosol particles with an electric mobility of about 0.03-0.5 cm2 V- 1 s- 1 and a diameter of about 1.5-7.5 nm. Intensive studies of new particle formation provided good knowledge about intermediate ions during burst events of atmospheric aerosol nucleation. Information about intermediate ions during quiet periods between the bursts remained poor. The new mobility analyzer SIGMA can detect air ions at concentrations of mobility fractions of about 1 cm- 3 and enables studying intermediate ions during quiet periods. It became evident that intermediate ions always exist in atmospheric air and should be considered an indicator and a mediator of aerosol nucleation. The annual average concentration of intermediate ions of one polarity in Tartu, Estonia, was about 40 cm- 3 while 5% of the measurements showed a concentration of less than 10 cm- 3. The fraction concentrations in logarithmic 1/8-decade mobility bins between 0.1 and 0.4 cm2 V- 1 s- 1 often dropped below 1 cm- 3. The bursts of intermediate ions at stations separated by around 100 km appeared to be correlated. The lifespan of intermediate ions in the atmosphere is a few minutes, and they cannot be carried by wind over long distances. Thus the observed long-range correlation of intermediate ions is explained by simultaneous changes in air composition in widely spaced stations. A certain amount of intermediate ion bursts, predominantly of negative polarity, are produced by the balloelectric effect at the splashing of water drops during rain. These bursts are usually excluded when speaking about new particle formation because the balloelectric particles are assumed not to grow to the size of the Aitken mode. The mobility distribution of balloelectric ions is uniform in shape in all measurements. The maximum is located at a mobility of about 0.2 cm2 V- 1 s- 1, which corresponds to the diameter of particles of about 2.5 nm.

  8. Effect of atmospheric CO2 on surface segregation and phase formation in La0.6Sr0.4Co0.2Fe0.8O3−δ thin films

    International Nuclear Information System (INIS)

    Highlights: • LSCF exhibits Sr surface segregation on high-temperature annealing. • The presence of atmospheric CO2 enhances the kinetics of Sr surface segregation. • At high-CO2 partial pressures, there is a significant coverage of the surface by Sr-rich phases. • The increase in kinetics is attributed to increased thermodynamic driving force for SrCO3 formation. - Abstract: The effects of atmospheric CO2 on surface segregation and phase formation in La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF-6428) were investigated. (0 0 1)-oriented LSCF-6428 thin films were deposited on lattice matched (1 1 0)-oriented NdGaO3 (NGO) substrates by pulsed laser deposition (PLD). Using the synchrotron technique of total reflection X-ray fluorescence (TXRF), it was found that the kinetics of Sr surface segregation was enhanced when annealing at 800 °C in a high-CO2 partial pressure, as compared to a similar anneal in a CO2-free atmosphere, with the oxygen partial pressure being constant in both cases. Hard X-ray photoelectron spectroscopy (HAXPES) measurements showed that the contribution of the surface carbonate to surface oxide phases increased significantly for the sample annealed in the high-CO2 atmosphere. Atomic force microscopy (AFM) studies showed enhanced surface phase formation during the high-CO2 partial pressure anneal. Density functional theory (DFT) calculations provide a thermodynamic basis for the enhanced kinetics of surface segregation in the presence of atmospheric CO2

  9. Atmospheric transformation of diesel emissions.

    Science.gov (United States)

    Zielinska, Barbara; Samy, Shar; McDonald, Jacob D; Seagrave, JeanClare

    2010-04-01

    The hypothesis of this study was that exposing diesel exhaust (DE*) to the atmosphere transforms its composition and toxicity. Our specific aims were (1) to characterize the gas- and particle-phase products of atmospheric transformations of DE under the influence of daylight, ozone (O3), hydroxyl (OH) radicals, and nitrate (NO3) radicals; and (2) to explore the biologic activity of DE before and after the transformations took place. The study was executed with the aid of the EUPHORE (European Photoreactor) outdoor simulation chamber facility in Valencia, Spain. EUPHORE is one of the largest and best-equipped facilities of its kind in the world, allowing investigation of atmospheric transformation processes under realistic ambient conditions (with dilutions in the range of 1:300). DE was generated on-site using a modern light-duty diesel engine and a dynamometer system equipped with a continuous emission-gas analyzer. The engine (a turbocharged, intercooled model with common-rail direct injection) was obtained from the Ford Motor Company. A first series of experiments was carried out in January 2005 (the winter 2005 campaign), a second in May 2005 (the summer 2005 campaign), and a third in May and June 2006 (the summer 2006 campaign). The diesel fuel that was used closely matched the one currently in use in most of the United States (containing 47 ppm sulfur and 15% aromatic compounds). Our experiments examined the effects on the composition of DE aged in the dark with added NO3 radicals and of DE aged in daylight with added OH radicals both with and without added volatile organic compounds (VOCs). In order to remove excess nitrogen oxides (NO(x)), a NO(x) denuder was devised and used to conduct experiments in realistic low-NO(x) conditions in both summer campaigns. A scanning mobility particle sizer was used to determine the particle size and the number and volume concentrations of particulate matter (PM) in the DE. O3, NO(x), and reactive nitrogen oxides (NO

  10. Atmospheric muons reconstruction with Antares

    International Nuclear Information System (INIS)

    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)

  11. 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.

  12. Light Atmosphere in Hospital Wards

    DEFF Research Database (Denmark)

    Stidsen, Lone Mandrup

    At the moment, the future of hospital design is a subject of interest and thereby also a subject of discussion. It is a fact that new hospitals have an increased focus on user perspectives and an interest for improving the physical environment in such a way it supports the user needs...... and preferences and thereby the experience of an admission to the hospital. Recent literature such as ‘Hospitals of the senses’ and ‘Healing Architecture’ presents research and design solutions focused on senses and experience of the design. The Danish Regions ask for ‘Evidence Based Design’ to future prove...... the hospitals by research base the design of the buildings. The present PhD project expands the existing knowledge of lighting research by focusing on the experienced light atmosphere. The project uses multi strategies of methodology based on a flexible design to elaborate on the sociocultural aspect of light...

  13. 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...... variation by height is adopted. A particular problem for simulation studies with finite time steps is the construction of a reflection rule different from the rule of perfect reflection at the boundaries such that the rule complies with the imposed skewness of the velocity distribution for particle...... 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...

  14. BIOSIGNATURE GASES IN H2-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS

    International Nuclear Information System (INIS)

    Super-Earth exoplanets are being discovered with increasing frequency and some will be able to retain stable H2-dominated atmospheres. We study biosignature gases on exoplanets with thin H2 atmospheres and habitable surface temperatures, using a model atmosphere with photochemistry and a biomass estimate framework for evaluating the plausibility of a range of biosignature gas candidates. We find that photochemically produced H atoms are the most abundant reactive species in H2 atmospheres. In atmospheres with high CO2 levels, atomic O is the major destructive species for some molecules. In Sun-Earth-like UV radiation environments, H (and in some cases O) will rapidly destroy nearly all biosignature gases of interest. The lower UV fluxes from UV-quiet M stars would produce a lower concentration of H (or O) for the same scenario, enabling some biosignature gases to accumulate. The favorability of low-UV radiation environments to accumulate detectable biosignature gases in an H2 atmosphere is closely analogous to the case of oxidized atmospheres, where photochemically produced OH is the major destructive species. Most potential biosignature gases, such as dimethylsulfide and CH3Cl, are therefore more favorable in low-UV, as compared with solar-like UV, environments. A few promising biosignature gas candidates, including NH3 and N2O, are favorable even in solar-like UV environments, as these gases are destroyed directly by photolysis and not by H (or O). A more subtle finding is that most gases produced by life that are fully hydrogenated forms of an element, such as CH4 and H2S, are not effective signs of life in an H2-rich atmosphere because the dominant atmospheric chemistry will generate such gases abiologically, through photochemistry or geochemistry. Suitable biosignature gases in H2-rich atmospheres for super-Earth exoplanets transiting M stars could potentially be detected in transmission spectra with the James Webb Space Telescope

  15. Study of Atmospheric Nitric Oxide

    Science.gov (United States)

    Dalgarno, A.

    1998-01-01

    We investigated the contribution of energetic nitrogen atoms to the production of nitric oxide in the thermosphere and their influence on the infrared emission spectrum. The nitric oxide molecules are important contributors to the cooling of the atmosphere. We first pointed out that in determining the energy distribution of the nitrogen atoms, it is important to take into account the thermal motion of the atmospheric gases. It had been ignored in all earlier studies. The source spectra are broadened considerably by the center of mass motion of the reactants. We worked out the consequences for the production of nitric oxide at night, using as sources of energetic N atoms, NO(+) + e yield N + O, N(D-2) + O yield N + O. The high energy tail is enhanced by orders of magnitude. We had earlier suggested (Sharma et al. 1993) that the reaction of energetic nitrogen atoms with O2 was responsible for the rotationally enhanced NO identified in the infrared spectrum. Our calculations provided quantitative confirmation of the suggestion. We proceeded to explore the validity of another approximation used in earlier analyses, the hard sphere approximation for the energy loss in elastic collisions. We carried out precise quantum mechanical calculations of the elastic 2 differential scattering of nitrogen atoms in collisions with oxygen atoms and showed that although the hard sphere approximation was nowhere of high precision, reasonable results could be obtained with an effective cross section of 6 x 10(exp 15)sq cm. We also initiated a program to include inelastic energy loss processes in the determination of the energy distribution function. We began a calculation of the rotation and vibrational excitation cross sections of molecular nitrogen and nitrogen atoms and developed a method for including inelastic energy loss as a function of scattering angle in the Boltzmann equation. A procedure for obtaining the solution of the Boltzman equation was worked out.

  16. Atmospheric Radiation Measurement Program Plan

    International Nuclear Information System (INIS)

    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

  17. Inhibition of corrosive processes in wet atmosphere

    International Nuclear Information System (INIS)

    Toluylalanine (TALA) is an additive in industrial cleaning baths and an effective temporary inhibitor of the corrosion of steel in neutral and weak alkaline electrolytes as well as in wet atmosphere. In dependence on the relative humidity of the atmosphere and the presence of hygroscopic salts, thin water films condense. The interaction between the metallic surface and the condensed liquid depends strongly on the surface tension. In our case we obtained a hydrophilic effect after the adsorption of the inhibitor. It can be assumed, that the water of the cleaning bath drains off the metal much better than in the case of hydrophobic layers. These effects in the range of monolayers could be studied with the quartz microbalance due to the high sensitivity of this technique. Improving our model, we obtained a lower and homogenous deposition of salt after the dipping in solution with TALA, which causes also a reduced homogenous condensation of water. Thus, corrosive attacks become less probable. The reactions in the cleaning bath and in films of condensed water were investigated by electrochemical methods in bulk electrolytes. In the presence of inhibitor the corrosion potential was shifted into the anodic direction, simultaneously the thickness of the oxide layer was increased in the presence of TALA. The characteristic data of pitting corrosion were obtained from anodic potentiodynamic sweeps. These results show, that pitting is hindered by TALA. Besides the stabilization of the passive layer, the growth of pits is also inhibited and repassivation is accelerated. From the polarization of probes precorroded at wet atmosphere we yielded in solutions with TALA an re-inhibition, too. Additionally we observed in unprotected solutions the sensitivity of this method to active corrosion centers, which cause pitting at lower overvoltages

  18. 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.)

  19. Time dependences of atmospheric Carbon dioxide fluxes

    CERN Document Server

    DeSalvo, Riccardo

    2014-01-01

    Understanding the lifetime of CO2 in the atmosphere is critical for predictions regarding future climate changes. A simple mass conservation analysis presented here generates tight estimations for the atmosphere's retention time constant. The analysis uses a leaky integrator model that combines the observed deficit (only less than 40% of CO2 produced from combustion of fossil fuels is actually retained in the atmosphere, while more than 60% is continuously shed) with the exponential growth of fossil fuel burning. It reveals a maximum characteristic time of less than 23 year for the transfer of atmospheric CO2 to a segregation sink. This time constant is further constrained by the rapid disappearance of 14C after the ban of atmospheric atomic bomb tests, which provides a lower limit of 18 years for this transfer. The study also generates evaluations of other CO2 fluxes, exchange time constants and volumes exchanged. Analysis of large harmonic oscillations of atmospheric CO2 concentration, often neglected in th...

  20. On the Stability of Super Earth Atmospheres

    CERN Document Server

    Heng, Kevin

    2012-01-01

    We investigate the stability of super Earth atmospheres around M stars using a 7-parameter, analytical framework. We construct stability diagrams in the parameter space of exoplanetary radius versus semi-major axis and elucidate the regions in which stable atmospheres may exist. We find that super Earth atmospheres with higher mean molecular weights and enhanced metallicities occupy a smaller region of allowed parameter space, because of the dual effects of diminished advection and enhanced radiative cooling. Furthermore, many super Earths which reside within the habitable zones of M stars may not possess stable, Earth-like atmospheres. We apply our stability diagrams to GJ 436b and GJ 1214b, and demonstrate that Earth-like elemental compositions for their atmospheres are disfavoured if these exoplanets possess solid surfaces and shallow atmospheres. Finally, we construct stability diagrams tailored to the Kepler dataset, for G and K stars, and predict that about half of the exoplanetary candidates are expect...

  1. Clouds and Hazes in Exoplanet Atmospheres

    CERN Document Server

    Marley, Mark 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 the role clouds play in influencing the spectra of planets as well as their habitability and detectability. We briefly summarize how clouds are treated in terrestrial climate models and consider the far simpler approaches that have been taken so far to model exoplanet clouds, the evidence for which we also review. Since clouds play a major role in the atmospheres of certain classes of brown dwarfs we briefly discuss brown dwarf cloud modeling as well. We also review how the scattering and extinction efficiencies of cloud p...

  2. On the role of dust storms in triggering atmospheric gravity waves observed in the middle atmosphere

    Directory of Open Access Journals (Sweden)

    S. K. Das

    2011-09-01

    Full Text Available Lower atmospheric perturbations often produce measurable effects in the middle and upper atmosphere. The present study demonstrates the response of the middle atmospheric thermal structure to the significant enhancement of the lower atmospheric heating effect caused by dust storms observed over the Thar Desert, India. Our study from multi-satellite observations of two dust storm events that occurred on 3 and 8 May 2007 suggests that dust storm events produce substantial changes in the lower atmospheric temperatures as hot spots which can become sources for gravity waves observed in the middle atmosphere.

  3. Radar remote sensing of the lower atmosphere

    OpenAIRE

    Karimian, Ali

    2012-01-01

    Non-standard radio wave propagation in the atmosphere is caused by anomalous changes of the atmospheric refractivity index. These changes, if not accounted for, can cause major problems in detection of the location of flying targets. Direct sensing of the atmospheric refractivity index by measuring humidity and temperature has been common practice in past. Refractivity from clutter (RFC) was developed in recent years to complement traditional ways of measuring the refractivity profile in mari...

  4. The general circulation of the atmosphere

    OpenAIRE

    Schneider, Tapio

    2006-01-01

    Theories of how Earth's surface climate may change in the future, of how it may have been in the past, and of how it is related to climates of other planets must build upon a theory of the general circulation of the atmosphere. The view of the atmospheric general circulation presented here focuses not on Earth's general circulation as such but on a continuum of idealized circulations with axisymmetric flow statistics. Analyses of observational data for Earth's atmosphere, simulations with ide...

  5. Atmospheric Prebiotic Chemistry and Organic Hazes

    OpenAIRE

    Trainer, Melissa G.

    2013-01-01

    Earth’s atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of prebiotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of orga...

  6. Atmospheric methods for nuclear test monitoring

    International Nuclear Information System (INIS)

    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

  7. Methane present in an extrasolar planet atmosphere

    OpenAIRE

    Swain, Mark R.; Vasisht, Gautam; Tinetti, Giovanna

    2008-01-01

    Molecules present in exoplanetary atmospheres are expected to strongly influence the atmospheric radiation balance, trace dynamical and chemical processes, and indicate the presence of disequilibrium effects. Since molecules have the potential to reveal the exoplanet atmospheric conditions and chemistry, searching for them is a high priority. The rotational-vibrational transition bands of water, carbon monoxide, and methane are anticipated to be the primary sources of non-continuum opacity in...

  8. Multisensor for detection of atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, J.; Sayago, I.; Horrillo, M.C.; Fernandez, M.J.; Ares, L.; Gomez-Espinosa, R.; Otero, L.; Garcia, M.; Aleixandre, M. [Lab. de Sensores, Inst. de Fisica Aplicada (IFA), Consejo Superior de Investigaciones Cientificas (CSIC), Serrano, Madrid (Spain); Baluk, S. [Lab. de Sensores, Inst. de Fisica Aplicada (IFA), Consejo Superior de Investigaciones Cientificas (CSIC), Serrano, Madrid (Spain)]|[Inst. Nacional de Tecnologia Industrial CITEI, San Martin-Buenos Aires (Argentina)

    2001-07-01

    A multisensor based on tin oxides has been utilised to detect gas mixtures for the atmospheric pollution control. The multisensor consists of 8 different sensing elements formed by tin oxide thin layers deposited by r.f. reactive sputtering. Some sensors were doped with Pt and Cr by sputtering. The multisensor device was placed in a stainless steel test chamber and it was characterized by DC electrical measurements. The designed system is a portable one and it permits the in situ measurement The pollutants detected are: nitrogen dioxide, carbon monoxide, toluene and propanal. Detections were carried out with single gas and gas mixture (two gases) in dry air at 250 C. The sensitivity and selectivity to these gases were studied. (orig.)

  9. The Abundance of Atomic Sulfur in the Atmosphere of Io

    CERN Document Server

    Feaga, L M; Feldman, P D; Feaga, Lori M.; Grath, Melissa A. Mc; Feldman, Paul D.

    2002-01-01

    Observations with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope have been used to constrain the atomic sulfur column density in Io's atmosphere. The SI 1479 dipole allowed and forbidden transition multiplets have been resolved for the first time at Io, enabling the study of both optically thick and thin transitions from a single atomic species. The allowed transitions contribute 62 +/- 8% and the forbidden transitions 38 +/- 8%, on average, to the total signal of the SI 1479 multiplets. Using the optically thick and thin transitions of SI 1479 observed near the limbs of Io, we derive a tangential atmospheric sulfur column abundance of 3.6*10^12 cm^-2 < N_s < 1.7*10^13 cm^-2, which is independent of electron temperature and density. A low density SO_2 atmosphere, N_so2 ~ 5-10*10^15 cm^-2, consistent with that inferred from other recent observations, is most consistent with these bounds.

  10. Fission product transport in the atmosphere

    International Nuclear Information System (INIS)

    In the present thesis,a theoretical treatment has been developed for investigating the fission product transport in the atmosphere, and expressing its underlying dynamics. Some basic material has been critically reviewed for the purpose of establishing the mathematical equations that govern the motion of a general pollutant - whether it is radioactive or not - in the atmosphere. Such review included the study of particulate matter motion in the atmosphere and radioactive cloud motion, together with the analysis of available mathematical models for atmospheric dispersion

  11. Atmospheric pollution. From processes to modelling

    International Nuclear Information System (INIS)

    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.)

  12. SMEX02 Atmospheric Aerosol Optical Properties Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  13. Rugged Optical Atmospheric Humidity Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trace species measurement on unmanned atmospheric research craft suitable for interplanetary travel is a demanding application for optical sensing techniques. Yet...

  14. Atmospheric neutrino flux calculation using the NRLMSISE00 atmospheric model

    CERN Document Server

    Honda, M; Kajita, T; Kasahara, K; Midorikawa, S

    2015-01-01

    In this paper, we extend the calculation of the atmospheric neutrino flux~\\cite{hkkm2004,hkkms2006,hkkm2011} to the sites in polar and tropical regions. In our earliest full 3D-calculation~\\cite{hkkm2004}, we used DPMJET-III~\\cite{dpm} for the hadronic interaction model above 5~GeV, and NUCRIN~\\cite{nucrin} below 5~GeV. We modified DPMJET-III as in Ref.~\\cite{hkkms2006} to reproduce the experimental muon spectra better, mainly using the data observed by BESS group~\\cite{BESSTeVpHemu}. In a recent work~\\cite{hkkm2011}, we introduced JAM interaction model for the low energy hadronic interactions. JAM is a nuclear interaction model developed with PHITS (Particle and Heavy-Ion Transport code System)~\\cite{phits}. In Ref.~\\cite{hkkm2011}, we could reproduce the observed muon flux at the low energies at balloon altitude with DPMJET-III above 32 GeV and JAM below that better than the combination of DPMJET-III above 5~GeV and NUCRIN below that. Besides the interaction model, we have also improved the calculation sche...

  15. Microwave diagnostics of atmospheric plasmas

    Science.gov (United States)

    Scott, David

    Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon

  16. Atmospheric radiative transfer simulation for atmospheric correction of remote sensing data

    Institute of Scientific and Technical Information of China (English)

    Yunfei Bao; Shengbo Chen

    2006-01-01

    The radiance leaving the earth-atmosphere system which can be sensed by a satellite borne radiometer is the sum of radiation emission from the earth surface and each atmospheric level that are transmitted to the top of the atmosphere. The radiation emission from the earth surface and the radiance of each atmospheric level can be separated from the radiance at the top the atmospheric level measured by a satellite borne radiometer. However, it is very difficult to measure the atmospheric radiance, especially the synchronous measurement with the satellite. Thus some atmospheric radiative transfer models have been developed to provide many options for modeling atmospheric radiation transport, such as LOWTRAN, MODTRAN, 6S, FASCODE, LBLRTM, SHARC, and SAMM. Meanwhile, these models can support the detailed detector system design, the optimization and evaluation of satellite mission parameters, and the data processing procedures. As an example, the newly atmospheric radiative transfer models, MODTRAN will be compared with other models after the atmospheric radiative transfer is described. And the atmospheric radiative transfer simulation procedures and their applications to atmospheric transmittance, retrieval of atmospheric elements, and surface parameters, will also be presented.

  17. Polar Atmospheric Dynamics of Jupiter

    Science.gov (United States)

    Sayanagi, Kunio M.; Mitchell, J. L.; Heavens, N. G.

    2012-10-01

    We investigate the transition in Jupiter's atmospheric dynamic regime between mid-latitudes to polar regions. Spacecraft observations of Jupiter have identified three distinct dynamical regimes in the cloud-top winds. In the equatorial region, a fast, broad jetstream blows eastward where no vortices are found. In the mid-latitudes, many vortices exist between the numerous jetstreams that alternate in wind direction between eastward and westward. On Jupiter, vortices become increasingly prevalent with latitude; poleward of 65 degree N/S latitudes, the banded structure that characterizes the lower latitudes becomes indiscernible, and the flow acquires an increasingly turbulent appearance with little zonal organization - we identify this regime as polar turbulence. Saturn also has a very similarly organized atmosphere, except that it maintains zonally organized cloud bands up to the poles and lacks polar turbulence. The zonal structure of Saturn culminates in the southern hemisphere with a hurricane-like cyclonic vortex residing precisely at south pole. Here, we focus on the transition from the mixed jet-vortex regime in the mid-latitudes to the vortex-dominated polar-regime of Jupiter. Using an idealized shallow-water model in a beta-plane channel, we test the stability of various scenarios that range between a jet-dominated flow and vortical turbulence. Since we are simulating a zone on the sphere rather than the full circulation, we test the sensitivity of the dynamics to latitude by varying the model’s beta-plane parameters, namely, the background Coriolis parameter f0 and its gradient beta. In addition, as we employ a 1 1/2-layer shallow-water model, we also vary the layer thickness and the bottom-layer topography to mimic a steeply varying thermal stratification (i.e., a potential vorticity front) by exploiting the topographic beta effects. We use the EPIC model (Dowling et al. 1998) to perform our numerical experiments. Our study is supported by a NASA Outer

  18. Lookup tables to compute high energy cosmic ray induced atmospheric ionization and changes in atmospheric chemistry

    OpenAIRE

    Atri, Dimitra; Melott, Adrian L.; Thomas, Brian C.

    2008-01-01

    A variety of events such as gamma-ray bursts and supernovae may expose the Earth to an increased flux of high-energy cosmic rays, with potentially important effects on the biosphere. Existing atmospheric chemistry software does not have the capability of incorporating the effects of substantial cosmic ray flux above 10 GeV . An atmospheric code, the NASA-Goddard Space Flight Center two-dimensional (latitude, altitude) time-dependent atmospheric model (NGSFC), is used to study atmospheric chem...

  19. Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution

    OpenAIRE

    J. Namieśnik; K. Skarżyńska; Ż Polkowska

    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.

  20. Improving practical atmospheric dispersion models

    International Nuclear Information System (INIS)

    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.)

  1. Tornadoes and other atmospheric vortices

    Science.gov (United States)

    Deissler, R. G.

    1976-01-01

    The growth of random vortices in an atmosphere with buoyant instability and vertical wind shear is studied along with the velocities in a single gravity-driven vortex; a frictionless adiabatic model which is supported by laboratory experiments is first considered. The effects of axial drag, heat transfer, and precipitation-induced downdrafts are then calculated. Heat transfer and axial drag tend to have stabilizing effects; they reduce the downdrafts of updrafts due to buoyancy. It is found that downdrafts or tornadic magnitude might occur in negatively-buoyant columns. The radial-inflow velocity required to maintain a given maximum tangential velocity in a tornado is determined by using a turbulent vortex model. Conditions under which radial-inflow velocities become sufficiently large to produce tangential velocities of tornadic magnitude are determined. The radial velocities in the outer regions, as well as the tangential velocities in the inner regions may be large enough to cause damage. The surface boundary layer, which is a region where large radial inflows can occur, is studied, and the thickness of the radial-inflow friction layer is estimated. A tornado model which involves a rotating parent cloud, as well as buoyancy and precipitation effects, is discussed.

  2. Atmospheric pressure plasma jet applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.; Herrmann, H.W.; Henins, I.; Selwyn, G.S. [Los Alamos National Lab., NM (United States)

    1998-12-31

    The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g., He/O2/H2O) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz RF. While passing through the plasma, the feedgas becomes excited, ionized or dissociated by electron impact. The fast-flowing effluent consists of ions and electrons, which are rapidly lost by recombination, highly reactive radicals (e.g., O, OH), and metastable species (e.g., O2). The metastable O2, which is reactive to hydrocarbon and other organic species, has been observed through optical emission spectroscopy to decrease by a factor of 2 from the APPJ nozzle exit to a distance of 10 cm. Unreacted metastable O2, and that which does not impinge on a surface, will then decay back to ordinary ground state O2, resulting in a completely dry, environmentally-benign form of surface cleaning. Applications such as removal of photoresist, oxide films and organic residues from wafers for the electronics industry, decontamination of civilian and military areas and personnel exposed to chemical or biological warfare agents, and paint (e.g., graffiti) removal are being considered.

  3. Atmospheric composition forecasting in Europe

    Science.gov (United States)

    Menut, L.; Bessagnet, B.

    2010-01-01

    The atmospheric composition is a societal issue and, following new European directives, its forecast is now recommended to quantify the air quality. It concerns both gaseous and particles species, identified as potential problems for health. In Europe, numerical systems providing daily air quality forecasts are numerous and, mostly, operated by universities. Following recent European research projects (GEMS, PROMOTE), an organization of the air quality forecast is currently under development. But for the moment, many platforms exist, each of them with strengths and weaknesses. This overview paper presents all existing systems in Europe and try to identify the main remaining gaps in the air quality forecast knowledge. As modeling systems are now able to reasonably forecast gaseous species, and in a lesser extent aerosols, the future directions would concern the use of these systems with ensemble approaches and satellite data assimilation. If numerous improvements were recently done on emissions and chemistry knowledge, improvements are still needed especially concerning meteorology, which remains a weak point of forecast systems. Future directions will also concern the use of these forecast tools to better understand and quantify the air pollution impact on health.

  4. Pulsating Helium Atmosphere White Dwarfs

    Science.gov (United States)

    Provencal, Judith; Montgomery, Michael H.; Bischoff-Kim, Agnes; Shipman, Harry; Nitta, Atsuko; Whole Earth Telescope Collaboration

    2015-08-01

    The overwhelming majority of all stars currently on the main sequence as well as those from earlier generations will or have ended their stellar lives as white dwarf stars. White dwarfs are rich forensic laboratories linking the history and future evolution of our Galaxy. Their structure and atmospheric composition provide evidence of how the progenitors lived, how they evolved, and how they died. This information reveals details of processes governing the behavior of contemporary main sequence stars. Combined with their distribution in luminosity/temperature, white dwarfs strongly constrain models of galactic and cosmological evolution.GD358 is among the brightest (mv =13.7) and best studied of the pulsating white dwarfs. This helium atmoshere pulsator (DBV) has an extensive photometric database spanning 30 years, including nine multisite Whole Earth Telescope campaigns. GD358 exhibits a range of behaviors, from drastic changes in excited pulsation modes to variable multiplet splittings. We use GD358 as a template for an examination of the DBV class, combining photometric results with recent COS spectroscopy. The results present new questions concerning DB formation and evolution.

  5. Atmospheric composition forecasting in Europe

    Directory of Open Access Journals (Sweden)

    L. Menut

    2010-01-01

    Full Text Available The atmospheric composition is a societal issue and, following new European directives, its forecast is now recommended to quantify the air quality. It concerns both gaseous and particles species, identified as potential problems for health. In Europe, numerical systems providing daily air quality forecasts are numerous and, mostly, operated by universities. Following recent European research projects (GEMS, PROMOTE, an organization of the air quality forecast is currently under development. But for the moment, many platforms exist, each of them with strengths and weaknesses. This overview paper presents all existing systems in Europe and try to identify the main remaining gaps in the air quality forecast knowledge. As modeling systems are now able to reasonably forecast gaseous species, and in a lesser extent aerosols, the future directions would concern the use of these systems with ensemble approaches and satellite data assimilation. If numerous improvements were recently done on emissions and chemistry knowledge, improvements are still needed especially concerning meteorology, which remains a weak point of forecast systems. Future directions will also concern the use of these forecast tools to better understand and quantify the air pollution impact on health.

  6. Total tritium measurement in atmosphere

    International Nuclear Information System (INIS)

    Measurement of tritium in the atmosphere is of strong interest wherever this radionuclide is used. Therefore, a method is proposed for the joint measurement of burnable tritium, independently from its physico-chemical form, and of tritiated water. The method consists of transforming the tritiated molecules of the gases present in the air volume into tritiated water by burning them together with a known quantity of hydrogen. The water vapor is condensed and added to a liquid scintillator. The scintillator is also able to dissolve conventional filters so that the tritium attached to particulate and concentrated on these filters can be jointly measured, as will be discussed in a future report. The overall detection limit of the method is approximately 64 Bq m-3 for a combustion period of 10 min (which corresponds to sampling an air volume of 15 L) and a counting period of 10 min. This limit, much lower than the derived air concentrations in the most unfavorable cases, allows the application of the method for safety purposes. Moreover, the method can be integrated into a general procedure for the measurement of tritium in different chemical forms, to be applied in case of necessity

  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. Basic research in meteorology and atmospheric physics

    Science.gov (United States)

    Miller, J. E.

    1975-01-01

    The effect was studied of the variations of the electromagnetic properties of the three phases of water on measurements of atmospheric and oceanographic parameters by microwave instruments aboard satellites. Other studies reported include: orbital detection of extrasolar planets, detection of stratospheric aerosols from earth orbit, chemistry of Jupiter's atmosphere, and stratospheric ozone.

  9. Energy, atmospheric chemistry, and global climate

    Science.gov (United States)

    Levine, Joel S.

    1991-01-01

    Global atmospheric changes due to ozone destruction and the greenhouse effect are discussed. The work of the Intergovernmental Panel on Climate Change is reviewed, including its judgements regarding global warming and its recommendations for improving predictive capability. The chemistry of ozone destruction and the global atmospheric budget of nitrous oxide are reviewed, and the global sources of nitrous oxide are described.

  10. Investigation on Atmospheric Corrosiveness in Hainan Province

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    According to the results of four-year exposure tests for carbon steel samples in Hainan province, the influences of meteorological factors and Cl- on atmospheric corrosion were investigated. The feature of atmospheric corrosion in this area was summarized. A corrosive map for the area was drawn. The corrosion products on carbon steel at some typical places were analyzed by XRD and XPS.

  11. Simulating super earth atmospheres in the laboratory

    Science.gov (United States)

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

    2016-01-01

    Several space missions, such as JWST, TESS and the very recently proposed ARIEL, or ground-based experiments, as SPHERE and GPI, have been proposed to measure the atmospheric transmission, reflection and emission spectra of extrasolar planets. The planet atmosphere characteristics and possible biosignatures will be inferred by studying planetary spectra in order to identify the emission/absorption lines/bands from atmospheric molecules such as water (H2O), carbon monoxide (CO), methane (CH4), ammonia (NH3), etc. In particular, it is important to know in detail the optical characteristics of gases in the typical physical conditions of the planetary atmospheres and how these characteristics could be affected by radiation driven photochemical and biochemical reaction. The main aim of the project `Atmosphere in a Test Tube' is to provide insights on exoplanet atmosphere modification due to biological intervention. This can be achieved simulating planetary atmosphere at different pressure and temperature conditions under the effects of radiation sources, used as proxies of different bands of the stellar emission. We are tackling the characterization of extrasolar planet atmospheres by mean of innovative laboratory experiments described in this paper. The experiments are intended to reproduce the conditions on warm earths and super earths hosted by low-mass M dwarfs primaries with the aim to understand if a cyanobacteria population hosted on a Earth-like planet orbiting an M0 star is able to maintain its photosynthetic activity and produce traceable signatures.

  12. The global atmospheric budget of ethanol revisited

    Directory of Open Access Journals (Sweden)

    W. V. Kirstine

    2012-01-01

    Full Text Available Ethanol is an important biogenic volatile organic compound, which is increasingly used as a fuel for motor vehicles; therefore, an improved understanding of its atmospheric cycle is important. In this paper we use three sets of observational data, measured emissions of ethanol from living plants, measured concentrations of ethanol in the atmosphere and measured hydroxyl concentrations in the atmosphere (by methyl chloroform titration, to make two independent estimates related to the rate of cycling of ethanol through the atmosphere. In the first estimate, simple calculations give the emission rate of ethanol from living plants as 26 (range, 10–38 Tg yr−1. This contributes significantly to the total global ethanol source of 42 (range, 25–56 Tg yr−1. In the second estimate, the total losses of ethanol from the global atmosphere are 70 (range, 50–90 Tg yr−1, with about three-quarters of the ethanol removed by reaction with hydroxyl radicals in the gaseous and aqueous phases of the atmosphere, and the remainder lost through wet and dry deposition to land. These values of both the source of ethanol from living plants and the removal of atmospheric ethanol via oxidation by hydroxyl radicals (derived entirely from observations are significantly larger than those in recent literature. We suggest that a revision of the estimate of global ethanol emissions from plants to the atmosphere to a value comparable with this analysis is warranted.

  13. 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…

  14. Carbonyl sulfide (OCS) in the Archean atmosphere

    DEFF Research Database (Denmark)

    Ueno, Yuichiro; Danielache, Sebastian Oscar; Johnson, Matthew Stanley;

    2009-01-01

    absorbs >200 nm region of solar UV flux. Further, we performed numerical simulation of atmospheric reactions including OCS chemistry and found that ppm-level OCS could be accumulated in a O2- free reducing atmosphere when CO/CO2 ratio is greater than 1. Therefore, appreciable amount of OCS is likely...

  15. Park power deficit due to atmospheric stability

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Barthelmie, Rebecca; Ott, Søren; Larsen, Gunner Chr.

    The purpose of this paper is to present a power deficit analysis based on offshore wind farm measurements with respect to the atmospheric stability classification. The result is used to validate wind farm prediction models under different inflow and atmospheric stability conditions...

  16. Affective Atmospheres in the House of Usher

    DEFF Research Database (Denmark)

    Brink, Dennis Meyhoff

    2016-01-01

    atmospheres in literary and cultural studies are extraordinarily productive for an analysis of Poe’s short story: on the one hand they can help us understand the many descriptions of affective atmospheres in Poe’s story, and on the other hand Poe’s text can help us discuss existing theories and develop new...

  17. Laser Micromachining In A Reactive Atmosphere

    Science.gov (United States)

    Shlichta, Paul J.; Zahaykevich, George

    1988-01-01

    Drilling of deep holes in silicon by laser beam aided by conducting operation in reactive atmosphere. Atmosphere reacts with material ejected from hole and converts material to gas flowing away from work area. Hole cleaner and more sharply defined, and debris do not spatter surface of work.

  18. Evolution of an Early Titan Atmosphere: Comment

    CERN Document Server

    Johnson, Robert E; Volkov, Alexey N

    2015-01-01

    Escape of an early atmosphere from Titan, during which time NH3 could be converted by photolysis into the present N2 dominated atmosphere, is an important problem in planetary science. Recently Gilliam and Lerman (2014) estimated escape driven by the surface temperature and pressure, which we show gave loss rates that are orders of magnitude too large. Their model, related to Jeans escape from an isothermal atmosphere, was used to show that escape driven only by surface heating would deplete the atmospheric inventory of N for a suggested Titan accretion temperature of ~355 K. Therefore, they concluded that the accretion temperature must be lower in order to retain the present Titan atmosphere. Here we show that the near surface atmospheric temperature is essentially irrelevant for determining the atmospheric loss rate from Titan and that escape is predominantly driven by solar heating of the upper atmosphere. We also give a rough estimate of the escape rate in the early solar system (~10^4 kg/s) consistent wi...

  19. 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.

  20. Atmospheric monitor for Telescope Array experiment

    Directory of Open Access Journals (Sweden)

    Tsunesada Y.

    2013-06-01

    Full Text Available The atmospheric monitoring is very important for the observation of air shower by air fluorescence technique. In the Telescope Array (TA experiment, LIDAR (LIght Detection And Ranging system and CLF (Central Laser Facility system have been used for the measurement of atmospheric transparency. The LIDAR system is located in the southeast of TA site. The CLF is located in the center of the TA site. The usefulness of the CLF and LIDAR systems is demonstrated by analyzing the time variation of atmospheric transparency with the systems. The two atmospheric monitor systems are complementary. Therefore, monitoring efficiency is advanced by a new LIDAR system that was installed at CLF system. Clouds are observed with CCD camera, IR camera and eye scan visual check. In addition, we have also measured atmospheric parameters at the ground level using several weather systems.

  1. Energetic particle influences in Earth's atmosphere

    Science.gov (United States)

    Aplin, Karen; Harrison, R. Giles; Nicoll, Keri; Rycroft, Michael; Briggs, Aaron

    2016-04-01

    Energetic particles from outer space, known as galactic cosmic rays, constantly ionise the entire atmosphere. During strong solar storms, solar energetic particles can also reach the troposphere and enhance ionisation. Atmospheric ionisation generates cluster ions. These facilitate current flow in the global electric circuit, which arises from charge separation in thunderstorms driven by meteorological processes. Energetic particles, whether solar or galactic in origin, may influence the troposphere and stratosphere through a range of different mechanisms, each probably contributing a small amount. Some of the suggested processes potentially acting over a wide spatial area in the troposphere include enhanced scavenging of charged aerosol particles, modification of droplet or droplet-droplet behavior by charging, and the direct absorption of infra-red radiation by the bending and stretching of hydrogen bonds inside atmospheric cluster-ions. As well as reviewing the proposed mechanisms by which energetic particles modulate atmospheric properties, we will also discuss new instrumentation for measurement of energetic particles in the atmosphere.

  2. Free Internal Waves in Polytropic Atmospheres

    CERN Document Server

    Ivanov, Mikhail I

    2011-01-01

    Free internal waves in polytropic atmospheres are studied (polytropic atmosphere is such one that the temperature of gas linearly depends on altitude). We suppose gas to be ideal and incompressible. Also, we regard the atmosphere of constant height with the "rigid lid" condition on its top to filter internal waves. If temperature, density and pressure of such undisturbed atmosphere do not depend on latitude and longitude then the internal waves are harmonic with apriori unknown eigenfrequencies, the problem permits separation of variables and reduces to the system of two ODE's. The first ODE (the Laplace's tidal equation) is analyzed by author earlier. The second ODE determines the vertical structure of the waves to be considered and has analytical solution for polytropic atmospheres. There are 6 dimensionless numbers, 2 for the Laplace's tidal equation and 4 for the vertical structure equation. The solution is a countable set of the eigenfrequencies and eigenfunctions of the vertical structure equation; ever...

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

    CERN Document Server

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

    2016-01-01

    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, incl...

  4. The global atmospheric electrical circuit and climate

    CERN Document Server

    Harrison, R G

    2004-01-01

    Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultrafine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution ca...

  5. The growth of organosilicon film using a hexamethyldisilazane/oxygen atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    An atmospheric pressure plasma jet, using a hexamethyldisilazane and oxygen mixture, was used to deposit an organosilicon thin film on polycarbonate (PC) substrates. The atmospheric pressure plasma jet deposited homogeneous thin films without unfavorable contamination from the plasma source. The surface properties of the organosilicon thin films were studied as a function of oxygen gas flow rate. The atmospheric pressure plasma deposited organosilicon thin films were analyzed using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectrometry and atomic forced microscopy. Surface analysis showed that atmospheric pressure plasma deposited films are more inorganic as the oxygen flow rate increases. The UV–vis spectra, detected in the range 300–800 nm, demonstrated improved transparency in the visible region and increased absorption in UV region of the spectrum. The improved hardness of the atmospheric pressure plasma deposited PC substrates was measured using a pencil hardness testing method and this was related to the chemical composition of the plasma deposited organosilicon thin films. The plasma jet allowed deposition of the coating without a chamber. - Highlights: ► Organosilicon thin films on polycarbonate (PC) by atmospheric pressure plasma jet. ► Properties of SiOx films vary with the injected oxygen flow rate in the plasma jet. ► Improved hardness of atmospheric pressure plasma deposited SiOx films achieved. ► Double-pipe atmospheric pressure plasma jet suitable for chamberless deposition

  6. The growth of organosilicon film using a hexamethyldisilazane/oxygen atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chun, E-mail: chunhuang@saturn.yzu.edu.tw; Wu, Shin-Yi; Tsai, Ching-Yuan; Liu, Wei-Ting

    2013-02-01

    An atmospheric pressure plasma jet, using a hexamethyldisilazane and oxygen mixture, was used to deposit an organosilicon thin film on polycarbonate (PC) substrates. The atmospheric pressure plasma jet deposited homogeneous thin films without unfavorable contamination from the plasma source. The surface properties of the organosilicon thin films were studied as a function of oxygen gas flow rate. The atmospheric pressure plasma deposited organosilicon thin films were analyzed using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectrometry and atomic forced microscopy. Surface analysis showed that atmospheric pressure plasma deposited films are more inorganic as the oxygen flow rate increases. The UV–vis spectra, detected in the range 300–800 nm, demonstrated improved transparency in the visible region and increased absorption in UV region of the spectrum. The improved hardness of the atmospheric pressure plasma deposited PC substrates was measured using a pencil hardness testing method and this was related to the chemical composition of the plasma deposited organosilicon thin films. The plasma jet allowed deposition of the coating without a chamber. - Highlights: ► Organosilicon thin films on polycarbonate (PC) by atmospheric pressure plasma jet. ► Properties of SiOx films vary with the injected oxygen flow rate in the plasma jet. ► Improved hardness of atmospheric pressure plasma deposited SiOx films achieved. ► Double-pipe atmospheric pressure plasma jet suitable for chamberless deposition.

  7. Atmospheric Prebiotic Chemistry and Organic Hazes

    Science.gov (United States)

    Trainer, Melissa G.

    2012-01-01

    Earth's atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of pre biotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of organic molecules is more productive in reduced atmospheres, yet the primitive Earth may not have been as reducing as earlier workers assumed, and recent research has reflected this shift in thinking. This work provides a survey of the range of chemical products that can be produced given a set of atmospheric conditions, with a particular focus on recent reports. Intertwined with the discussion of atmospheric synthesis is the consideration of an organic haze layer, which has been suggested as a possible ultraviolet shield on the anoxic early Earth. Since such a haze layer - if formed - would serve as a reservoir for organic molecules, the chemical composition of the aerosol should be closely examined. The results highlighted here show that a variety of products can be formed in mildly reducing or even neutral atmospheres, demonstrating that contributions of atmospheric synthesis to the organic inventory on early Earth should not be discounted. This review intends to bridge current knowledge of the range of possible atmospheric conditions in the prebiotic environment and pathways for synthesis under such conditions by examining the possible products of organic chemistry in the early atmosphere.

  8. An investigation into the optimum thickness of titanium dioxide thin films synthesized by using atmospheric pressure chemical vapour deposition for use in photocatalytic water oxidation.

    Science.gov (United States)

    Hyett, Geoffrey; Darr, Jawwad A; Mills, Andrew; Parkin, Ivan P

    2010-09-10

    Twenty eight films of titanium dioxide of varying thickness were synthesised by using atmospheric pressure chemical vapour deposition (CVD) of titanium(IV) chloride and ethyl acetate onto glass and titanium substrates. Fixed reaction conditions at a substrate temperature of 660 °C were used for all depositions, with varying deposition times of 5-60 seconds used to control the thickness of the samples. A sacrificial electron acceptor system composed of alkaline sodium persulfate was used to determine the rate at which these films could photo-oxidise water in the presence of 365 nm light. The results of this work showed that the optimum thickness for CVD films on titanium substrates for the purposes of water oxidation was ≈200 nm, and that a platinum coating on the reverse of such samples leads to a five-fold increase in the observed rate of water oxidation. PMID:20645333

  9. Mysteries of the Lunar Atmosphere

    Science.gov (United States)

    Killen, R. M.; Hurley, D. M.

    2012-12-01

    The lunar atmosphere has been probed by various instruments since the Apollo program, and continues to be measured today by the instruments onboard the Lunar Reconnaissance Orbiter, LRO. But like Sisyphus' trek, the progress has not been linear. LAMP, The Lyman Alpha Mapping Project, onboard LRO, measured He in the lunar exosphere, confirming the Apollo 17 result from the Lunar Atmosphere Composition Experiment (LACE) (Hoffman et al., 1973), but LAMP did not observe Ar although the expected 0.1 R should have been detectable by their instrument (Gladstone et al., Science, 2010). A surfeit of O+ was reported in the lunar wake (Mall et al. 1998; Hilchenbach et al. 1992;1993), but the origin of those ions is unknown, since oxygen has not been seen. Water and OH were measured on the surface of the moon, but theory tells us that efficiencies of production of water by solar wind proton bombardment may be low (Burke et al., Icarus, 2011). Starukhina and Shukaratov (LPSC, abstract 1385, 2010) suggest that the observed diurnal variation in the 3 micron band at the moon is due to thermal emission and not to variation in OH. LAMP observed Hg vapor following the LCROSS impact into Cabeus crater, but Hg atoms at 800 K (Wooden et al., LPSC abstract 2025, 2010) are too heavy to reach the altitudes where they would be exposed to sunlight, and thereby resonantly scatter photons, unless they are entrained in a gas with bulk velocity 3.5 km/s (Hurley et al., JGR, 2012). This bulk velocity is high for a 2 km/s impact. Another mystery from LCROSS is the H2 energy budget. Given the large amount of H2 observed after the LCROSS impact, and the high velocity required (a few km/s) to get in the field of view when it did, the kinetic energy associated with the H2 is too large of a fraction of the impactor energy. One possibility is that the H2 is produced by an exothermic reaction, which has implications for how it is stored in the regolith in permanently shadowed regions. The Na density is

  10. Biosignature Gases in H2-Dominated Atmospheres on Rocky Exoplanets

    CERN Document Server

    Seager, S; Hu, R

    2013-01-01

    (Abridged) Super Earth exoplanets are being discovered with increasing frequency and some will be able to retain stable H2-dominated atmospheres. We study biosignature gases on exoplanets with thin H2 atmospheres and habitable surface temperatures, by using a model atmosphere with photochemistry, and biomass estimate framework for evaluating the plausibilty of a range of biosignature gas candidates. We find that photochemically produced H atoms are the most abundant reactive species in H2 atmospheres. In atmospheres with high CO2 levels, atomic O is the major destructive species for some molecules. In sun-Earth-like UV radiation environments, H (and in some cases O) will rapidly destroy nearly all biosignature gases of interest. The lower UV fluxes from UV quiet M stars would produce a lower concentration of H (or O) for the same scenario, enabling some biosignature gases to accumulate. The favorability of low-UV radiation environments to in an H2 atmosphere is closely analogous to the case of oxidized atmosp...

  11. Can mushrooms fix atmospheric nitrogen?

    Indian Academy of Sciences (India)

    H S Jayasinghearachchi; Gamini Seneviratne

    2004-09-01

    It is generally reported that fungi like Pleurotus spp. can fix nitrogen (N2). The way they do it is still not clear. The present study hypothesized that only associations of fungi and diazotrophs can fix N2. This was tested in vitro. Pleurotus ostreatus was inoculated with a bradyrhizobial strain nodulating soybean and P. ostreatus with no inoculation was maintained as a control. At maximum mycelial colonization by the bradyrhizobial strain and biofilm formation, the cultures were subjected to acetylene reduction assay (ARA). Another set of the cultures was evaluated for growth and nitrogen accumulation. Nitrogenase activity was present in the biofilm, but not when the fungus or the bradyrhizobial strain was alone. A significant reduction in mycelial dry weight and a significant increase in nitrogen concentration were observed in the inoculated cultures compared to the controls. The mycelial weight reduction could be attributed to C transfer from the fungus to the bradyrhizobial strain, because of high C cost of biological N2 fixation. This needs further investigations using 14C isotopic tracers. It is clear from the present study that mushrooms alone cannot fix atmospheric N2. But when they are in association with diazotrophs, nitrogenase activity is detected because of the diazotrophic N2 fixation. It is not the fungus that fixes N2 as reported earlier. Effective N2 fixing systems, such as the present one, may be used to increase protein content of mushrooms. Our study has implications for future identification of as yet unidentified N2 systems occurring in the environment.

  12. Atmospheric effects of nuclear war

    International Nuclear Information System (INIS)

    The above uncertainties in the nuclear winter calculations are not one-sided. It is possible that certain errors would cause over estimation of the effects, while others could just as easily cause underestimation. Although the calculations involve material and processes that are complex, and for which the present state of knowledge is limited, the rather simple 1-dimensional models were quite correct in establishing the possibility of large-scale climatic perturbations following a nuclear war. The main conclusions regarding the possible climate effects of the nuclear war are: for large smoke injections, occurring between April and September in the northern hemisphere, land surface temperatures could decrease by 10-25 degrees C below normal in continental areas within a few days; the initial smoke distribution would be patchy, so temperature fluctuations could be spatially and temporally quite variable; within a few weeks, the smoke would be spread throughout much of the northern hemisphere. For spring-summer injections, a substantial fraction of the smoke would be transported, by solar heating, up into the stratosphere; surface temperatures of much of the northern hemisphere could drop to wintertime levels. Precipitation would also be affected; and stratospheric smoke could also be transported toward the equator, resulting in atmospheric perturbations in the southern hemisphere. Although recent developments have indicated that surface temperature reductions may be 25% less than suggested earlier, there is substantial reason to believe that severe climatic perturbations are the probable outcome of nuclear war and that these disturbances could cause more human casualties globally than the direct effects

  13. UFOMOD - atmospheric dispersion and deposition

    International Nuclear Information System (INIS)

    The report gives an introduction into the modelling of atmospheric dispersion and deposition which has been implemented in the new program system UFOMOD for assessing the consequences after nuclear accidents. According to the new structure of UFOMOD, different trajectory models with ranges of validity near to the site and at far distances are applied. Emphasis is laid on the description of the segmented plume model MUSEMET and its affilated submodels, being the removal of activity from the cloud by dry and wet deposition, and special effects like plume rise and the behaviour of plumes released into building wakes. In addition, the evaluation of γ-dose correction factors to take account of the finite extent of the radioactive plume in the near range (up to about 20 km) are described. Only brief introductions are given into the principles of the other models available: the puff model RIMPUFF, the long-range puff model MESOS, and the special straight-line Gaussian model ISOLA which are used if low-level long-duration releases are considered. To define starting times of weather sequences and the probabilities of occurrence of these sequences, it is convenient to perform stratified sampling. Therefore, the preprocessing program package METSAM has been developed to perform for generic ACAs a random sampling of weather sequences out off a population of classified weather conditions. The sampling procedure and a detailed input/output (I/O) description is presented and an additional appendix, respectively. A general overview on the I/O structure of MUSEMET as well as a brief user guide to run the KfK version of the MESOS code are also given in the appendix. (orig.)

  14. Atmospheric Entry Experiments at IRS

    Science.gov (United States)

    Auweter-Kurtz, M.; Endlich, P.; Herdrich, G.; Kurtz, H.; Laux, T.; Löhle, S.; Nazina, N.; Pidan, S.

    2002-01-01

    Entering the atmosphere of celestial bodies, spacecrafts encounter gases at velocities of several km/s, thereby being subjected to great heat loads. The thermal protection systems and the environment (plasma) have to be investigated by means of computational and ground facility based simulations. For more than a decade, plasma wind tunnels at IRS have been used for the investigation of TPS materials. Nevertheless, ground tests and computer simulations cannot re- place space flights completely. Particularly, entry mission phases encounter challenging problems, such as hypersonic aerothermodynamics. Concerning the TPS, radiation-cooled materials used for reuseable spacecrafts and ablator tech- nologies are of importance. Besides the mentioned technologies, there is the goal to manage guidance navigation, con- trol, landing technology and inflatable technologies such as ballutes that aim to keep vehicles in the atmosphere without landing. The requirement to save mass and energy for planned interplanetary missions such as Mars Society Balloon Mission, Mars Sample Return Mission, Mars Express or Venus Sample Return mission led to the need for manoeuvres like aerocapture, aero-breaking and hyperbolic entries. All three are characterized by very high kinetic vehicle energies to be dissipated by the manoeuvre. In this field flight data are rare. The importance of these manoeuvres and the need to increase the knowledge of required TPS designs and behavior during such mission phases point out the need of flight experiments. As result of the experience within the plasma diagnostic tool development and the plasma wind tunnel data base, flight experiments like the PYrometric RE-entry EXperiment PYREX were developed, fully qualified and successfully flown. Flight experiments such as the entry spectrometer RESPECT and PYREX on HOPE-X are in the conceptual phase. To increase knowledge in the scope of atmospheric manoeuvres and entries, data bases have to be created combining both

  15. Discovery of carbon monoxide in the upper atmosphere of Pluto

    OpenAIRE

    Greaves, J.S.; Helling, Ch.; Friberg, P.

    2011-01-01

    Pluto's icy surface has changed colour and its atmosphere has swelled since its last closest approach to the Sun in 1989. The thin atmosphere is produced by evaporating ices, and so can also change rapidly, and in particular carbon monoxide should be present as an active thermostat. Here we report the discovery of gaseous CO via the 1.3mm wavelength J=2-1 rotational transition, and find that the line-centre signal is more than twice as bright as a tentative result obtained by Bockelee-Morvan ...

  16. Atmospheric Laboratory for Applications and Science Payload

    Science.gov (United States)

    1994-01-01

    This is an STS-66 mission onboard photo of the Space Shuttle Orbiter Atlantis showing the payload of the third Atmospheric Laboratory for Applications and Science (ATLAS-3) mission. During the ATLAS missions, international teams of scientists representing many disciplines combined their expertise to seek answers to complex questions about the atmospheric and solar conditions that sustain life on Earth. The ATLAS program specifically investigated how Earth's middle and upper atmospheres and climate are affected by by the sun and by products of industrial and agricultural activities on Earth. Thirteen ATLAS instruments supported experiments in atmospheric sciences, solar physics, space plasma physics, and astronomy. The instruments were mounted on two Spacelab pallets in the Space Shuttle payload bay. The ATLAS-3 mission continued a variety of atmospheric and solar studies to improve understanding of the Earth's atmosphere and its energy input from the sun. A key scientific objective was to refine existing data on variations in the fragile ozone layer of the atmosphere. The Orbiter Atlantis was launched on November 3, 1994 for the ATLAS-3 mission (STS-66).

  17. LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

    International Nuclear Information System (INIS)

    Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 1800, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 300. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 740; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 900, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.

  18. SWiFT site atmospheric characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, Christopher Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ennis, Brandon Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    Historical meteorological tall tower data are analyzed from the Texas Tech University 200 m tower to characterize the atmospheric trends of the Scaled Wind Farm Technologies (SWiFT) site. In this report the data are analyzed to reveal bulk atmospheric trends, temporal trends and correlations of atmospheric variables. Through this analysis for the SWiFT turbines the site International Electrotechnical Commission (IEC) classification is determined to be class III-C. Averages and distributions of atmospheric variables are shown, revealing large fluctuations and the importance of understanding the actual site trends as opposed to simply using averages. The site is significantly directional with the average wind speed from the south, and particularly so in summer and fall. Site temporal trends are analyzed from both seasonal (time of the year) to daily (hour of the day) perspectives. Atmospheric stability is seen to vary most with time of day and less with time of year. Turbulence intensity is highly correlated with stability, and typical daytime unstable conditions see double the level of turbulence intensity versus that experienced during the average stable night. Shear, veer and atmospheric stability correlations are shown, where shear and veer are both highest for stable atmospheric conditions. An analysis of the Texas Tech University tower anemometer measurements is performed which reveals the extent of the tower shadow effects and sonic tilt misalignment.

  19. Advances in spacecraft atmospheric entry guidance

    Science.gov (United States)

    Benito Manrique, Joel

    acceleration guidance approach successfully used in missions like the Space Shuttle. Based on this approach, a new planner has been developed that is computationally fast and provides trajectories with both high final altitude and high control authority. A new tracking law based on nonlinear predictive control has been developed to track the reference trajectory. The new tracking law accounts for control saturation, which is a common feature of trajectories in the thin Martian atmosphere with a low lift vehicle. Finally, a final position guidance algorithm that aligns the vehicle's heading towards the target and provides altitude and range control, has been developed. The new guidance algorithm provides increased accuracy as well as higher final altitude compared to an entry guidance algorithm representative of the current capabilities.

  20. Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy

    Science.gov (United States)

    Wyttenbach, Aurélien; Ehrenreich, David

    2015-12-01

    The field of exoplanet atmospheres is booming thanks to (low-resolution) space-borne spectrographs and high-resolution (narrow-ranged) NIR spectrographs on ground-based 8m-class telescopes. Atmospheres are important because they are our observing window on the physical, chemical, and evolutionary processes occurring on exoplanets. Transiting exoplanets are the best suitable targets for atmospheric studies. Observing a transit in different filters or with a spectrograph reveals the transmission spectrum of the planet atmosphere. More than one decade of such observations allowed the exploration of these remote words by detecting some constituents of their atmospheres, but revealing also the presence of scattering hazes and clouds in several exoplanets preventing the detection of major chemical constituents at low to medium resolution even from space.Transit observations from the ground with stabilised high-resolution spectrograph, such HARPS, have key roles to play in this context. Observation of the hot-jupiter HD 189733b with HARPS allow the detection of sodium in the planet atmosphere. The high-resolution transmission spectra allowed to probe a new region high in the atmosphere and revealed rapid winds and a heating thermosphere. This new use of the famous planet hunter turned HARPS into a powerful exoplanet characterisation machine. It has the precision level of the Hubble Space Telescope, albeit at 20 higher resolution.A survey of a large set of known hot transiting exoplanets with HARPS and later with ESPRESSO will allow the detection of key tracers of atmospheric physics, chemistry, and evolution, above the scattering haze layers known to dominate low-resolution visible spectra of exoplanets.Such observation, in total sinergy with other technics, will rmly establish stabilised, high-resolution spectrographs on 4m telescopes as corner-stones for the characterisation of exoplanets. This is instrumental considering the upcoming surveys (NGTS,K2, CHEOPS, TESS

  1. The Radiometer Atmospheric Cubesat Experiment

    Science.gov (United States)

    Lim, B.; Bryk, M.; Clark, J.; Donahue, K.; Ellyin, R.; Misra, S.; Romero-Wolf, A.; Statham, S.; Steinkraus, J.; Lightsey, E. G.; Fear, A.; Francis, P.; Kjellberg, H.; McDonald, K.

    2014-12-01

    The Jet Propulsion Laboratory (JPL) has been developing the Radiometer Atmospheric CubeSat Experiment (RACE) since 2012, which consists of a water vapor radiometer integrated on a 3U CubeSat platform. RACE will measure 2 channels of the 183 GHz water vapor line, and will be used to validate new low noise amplifier (LNA) technology and a novel amplifier based internal calibration subsystem. The 3U spacecraft is provided by the University of Texas at Austin's Satellite Design Laboratory. RACE will advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and a CubeSat 183 GHz radiometer system from TRL 4 to TRL 7. Measurements at 183 GHz are used to retrieve integrated products and vertical profiles of water vapor. Current full scale satellite missions that can utilize the technology include AMSU, ATMS, SSMIS and Megha-Tropiques. The LNAs are designed at JPL, based on a 35 nm indium phosphide (InP) high-electron-mobility transistors (HEMT) technology developed by Northrop Grumman. The resulting single chip LNAs require only 25 mW of power. Current pre-launch instrument performance specifications include an RF gain of over 30 dB and a room noise figure of 5dB. If a coupler based calibration system is shown to be sufficient, future receiver systems will have noise figures < 4 dB. The gain and noise figure variation over temperature is approximately 0.55 dB/K. The NEDT of the system is < 1K, and on orbit performance is expected to improve due to the thermal environment. The current system is configured for direct detection to reduce power consumption by eliminating the need for a local oscillator. A 2012 NASA CubeSat Launch Initiative (CSLI) selection, RACE is manifested for launch on the Orbital 3 (Orb-3) mission scheduled for October 2014. RACE will be deployed from the International Space Station (ISS) by NanoRacks.

  2. Atmospheric pressure plasma for surface modification

    CERN Document Server

    Wolf, Rory A

    2012-01-01

    This Book's focus and intent is to impart an understanding of the practical application of atmospheric plasma for the advancement of a wide range of current and emerging technologies. The primary key feature of this book is the introduction of over thirteen years of practical experimental evidence of successful surface modifications by atmospheric plasma methods. It offers a handbook-based approach for leveraging and optimizing atmospheric plasma technologies which are currently in commercial use. It also offers a complete treatment of both basic plasma physics and industrial plasma process

  3. Containment atmospheric response (CAR) scoping study

    International Nuclear Information System (INIS)

    The primary objectives of the Containment Atmospheric Response (CAR) subtask are to identify and evaluate thermodynamic phenomena occurring in the containment atmosphere during postulated gas-cooled reactor depressurization events that may affect the release of fission products to the environment. The release of fission products to the environment can be altered if the containment function fails, if the amount of plateout in the containment is changed or if the performance of the containment atmospheric cleanup system is impaired. A knowledge of the blowdown phenomena can also provide guidelines for locating reactor shutdown equipment and establishing requirements for the CACS

  4. Effect of atmospheric pollution on health

    International Nuclear Information System (INIS)

    In recent years the incidence of smog episodes and their intensity have gone down considerably and difference in atmospheric pollutant levels between urban and rural areas is very small. Even the sudden moderate elevation of atmospheric pollution during winter months affects the pulmonary function adversely and provokes increased respiratory symptomes. The prevalence of rhinitis and allergy is more frequent both in adults and in children in urban townships than in rural areas. It has also been observed that industrial city dwellers have inferior pulmonary function. Very recent results indicate possible interaction between atmospheric pollutant levels and regeneration process following airways infection in yound children. (orig.)

  5. Updating the science of atmospheric electricity

    Science.gov (United States)

    Pinto, Osmar, Jr.; Williams, Earle R.

    2011-12-01

    XIV International Conference on Atmospheric Electricity; Rio de Janeiro, Brazil, 7-12 August 2011 The main goal of the XIV International Conference on Atmospheric Electricity (ICAE 2011) was to provide a comprehensive description of the status of knowledge in the field of atmospheric electricity, as well as to provide an opportunity for extensive interaction among researchers in this field. The history of the ICAE goes back to the first conference held in May 1954 in Portsmouth, N. H. The conference was attended by 51 scientists from 10 countries, and only three topics were addressed: fair weather electricity, thunderstorm electrification, and lightning.

  6. HLINOP: Hydrogen LINe OPacity in stellar atmospheres

    Science.gov (United States)

    Barklem, P. S.; Piskunov, N.

    2015-07-01

    HLINOP is a collection of codes for computing hydrogen line profiles and opacities in the conditions typical of stellar atmospheres. It includes HLINOP for approximate quick calculation of any line of neutral hydrogen (suitable for model atmosphere calculations), based on the Fortran code of Kurucz and Peterson found in ATLAS9. It also includes HLINPROF, for detailed, accurate calculation of lower Balmer line profiles (suitable for detailed analysis of Balmer lines) and HBOP, to implement the occupation probability formalism of Daeppen, Anderson and Milhalas (1987) and thus account for the merging of bound-bound and bound-free opacity (used often as a wrapper to HLINOP for model atmosphere calculations).

  7. Clear sky atmosphere at cm-wavelengths from climatology data

    CERN Document Server

    Lew, Bartosz

    2015-01-01

    We utilise ground-based, balloon-born and satellite climatology data to reconstruct site and season-dependent vertical profiles of precipitable water vapour (PWV). We use these profiles to numerically solve radiative transfer through the atmosphere, and derive atmospheric brightness temperature ($T_{\\rm atm}$) and optical depth ($\\tau$) at the centimetre wavelengths. We validate the reconstruction by comparing the model column PWV, with photometric measurements of PWV, performed in the clear sky conditions towards the Sun. Based on the measurements, we devise a selection criteria to filter the climatology data to match the PWV levels to the expectations of the clear sky conditions. We apply the reconstruction to the location of the Polish 32-metre radio telescope, and characterise $T_{\\rm atm}$ and $\\tau$ year-round, at selected frequencies. We also derive the zenith distance dependence for these parameters, and discuss shortcomings of using planar, single-layer, and optically thin atmospheric model approxima...

  8. Atmospheric-pressure guided streamers for liposomal membrane disruption

    Science.gov (United States)

    Svarnas, P.; Matrali, S. H.; Gazeli, K.; Aleiferis, Sp.; Clément, F.; Antimisiaris, S. G.

    2012-12-01

    The potential to use liposomes (LIPs) as a cellular model in order to study interactions of cold atmospheric-pressure plasma with cells is herein investigated. Cold atmospheric-pressure plasma is formed by a dielectric-barrier discharge reactor. Large multilamellar vesicle liposomes, consisted of phosphatidylcholine and cholesterol, are prepared by the thin film hydration technique, to encapsulate a small hydrophilic dye, i.e., calcein. The plasma-induced release of calcein from liposomes is then used as a measure of liposome membrane integrity and, consequently, interaction between the cold atmospheric plasma and lipid bilayers. Physical mechanisms leading to membrane disruption are suggested, based on the plasma characterization including gas temperature calculation.

  9. Atmospheric-pressure guided streamers for liposomal membrane disruption

    International Nuclear Information System (INIS)

    The potential to use liposomes (LIPs) as a cellular model in order to study interactions of cold atmospheric-pressure plasma with cells is herein investigated. Cold atmospheric-pressure plasma is formed by a dielectric-barrier discharge reactor. Large multilamellar vesicle liposomes, consisted of phosphatidylcholine and cholesterol, are prepared by the thin film hydration technique, to encapsulate a small hydrophilic dye, i.e., calcein. The plasma-induced release of calcein from liposomes is then used as a measure of liposome membrane integrity and, consequently, interaction between the cold atmospheric plasma and lipid bilayers. Physical mechanisms leading to membrane disruption are suggested, based on the plasma characterization including gas temperature calculation.

  10. Atmospheric-pressure guided streamers for liposomal membrane disruption

    Energy Technology Data Exchange (ETDEWEB)

    Svarnas, P.; Aleiferis, Sp. [High Voltage Laboratory, Department of Electrical and Computer Engineering, University of Patras, Rion 26504 (Greece); Matrali, S. H. [Pharmaceutical Technology Laboratory, Department of Pharmacy, University of Patras, Rion 26504 (Greece); Gazeli, K. [High Voltage Laboratory, Department of Electrical and Computer Engineering, University of Patras, Rion 26504 (Greece); IPREM-LCABIE, Plasmas et Applications, UPPA, 64000 Pau (France); Clement, F. [IPREM-LCABIE, Plasmas et Applications, UPPA, 64000 Pau (France); Antimisiaris, S. G. [Pharmaceutical Technology Laboratory, Department of Pharmacy, University of Patras, Rion 26504 (Greece); Institute of Chemical Engineering Sciences (ICES)-FORTH, Rion 26504 (Greece)

    2012-12-24

    The potential to use liposomes (LIPs) as a cellular model in order to study interactions of cold atmospheric-pressure plasma with cells is herein investigated. Cold atmospheric-pressure plasma is formed by a dielectric-barrier discharge reactor. Large multilamellar vesicle liposomes, consisted of phosphatidylcholine and cholesterol, are prepared by the thin film hydration technique, to encapsulate a small hydrophilic dye, i.e., calcein. The plasma-induced release of calcein from liposomes is then used as a measure of liposome membrane integrity and, consequently, interaction between the cold atmospheric plasma and lipid bilayers. Physical mechanisms leading to membrane disruption are suggested, based on the plasma characterization including gas temperature calculation.

  11. Nano-particle size-dependent charging and electro-deposition in dielectric barrier discharges at atmospheric pressure for thin SiO{sub x} film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jidenko, N [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France); Jimenez, C [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Massines, F [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Borra, J-P [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France)

    2007-07-21

    This paper focuses on charging and electro-deposition of nano-particles produced in a mixture of silane and nitrous oxide diluted in N{sub 2}, by dielectric barrier discharge (DBD) at atmospheric pressure for SiO{sub x} film deposition. Townsend discharge (TD) and filamentary discharge (FD) are compared with and without SiH{sub 4}. Without SiH{sub 4}, particles are produced by filament-surface interaction. Both filament-surface and plasma-silane interactions lead to bimodal particle size distributions from nucleation and agglomeration. With SiH{sub 4}, particle formation and growth imply the same mechanisms in TD and FD. Faster dynamics in FD are related to higher local volume energy density than in TD. From scanning electron microscope images of the film and measurements downstream of the DBD reactor, the diameter of the particle produced is below 50 nm. An analytical model of electro-collection in an ac electric field is used to investigate nano-particle charging. To account for selective electro-deposition leading to particles smaller than 50 nm being included in the layer and to particle size distribution measured downstream of the DBD, the same size-dependent charging and electro-deposition of particle are involved, with different charging dynamics in TD and FD.

  12. The Atmosphere and Climate of Venus

    Science.gov (United States)

    Bullock, M. A.; Grinspoon, D. H.

    Venus lies just sunward of the inner edge of the Sun's habitable zone. Liquid water is not stable. Like Earth and Mars, Venus probably accreted at least an ocean's worth of water, although there are alternative scenarios. The loss of this water led to the massive, dry CO2 atmosphere, extensive H2SO4 clouds (at least some of the time), and an intense CO2 greenhouse effect. This chapter describes the current understanding of Venus' atmosphere, established from the data of dozens of spacecraft and atmospheric probe missions since 1962, and by telescopic observations since the nineteenth century. Theoretical work to model the temperature, chemistry, and circulation of Venus' atmosphere is largely based on analogous models developed in the Earth sciences. We discuss the data and modeling used to understand the temperature structure of the atmosphere, as well as its composition, cloud structure, and general circulation. We address what is known and theorized about the origin and early evolution of Venus' atmosphere. It is widely understood that Venus' dense CO2 atmosphere is the ultimate result of the loss of an ocean to space, but the timing of major transitions in Venus' climate is very poorly constrained by the available data. At present, the bright clouds allow only 20% of the sunlight to drive the energy balance and therefore determine conditions at Venus' surface. Like Earth and Mars, differential heating between the equator and poles drives the atmospheric circulation. Condensable species in the atmosphere create clouds and hazes that drive feedbacks that alter radiative forcing. Also in common with Earth and Mars, the loss of light, volatile elements to space produces long-term changes in composition and chemistry. As on Earth, geologic processes are most likely modifying the atmosphere and clouds by injecting gases from volcanos as well as directly through chemical reactions with the surface. The sensitivity of Venus' atmospheric energy balance is quantified in

  13. Soil-vegetation-atmosphere transfer modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ikonen, J.P.; Sucksdorff, Y. [Finnish Environment Agency, Helsinki (Finland)

    1996-12-31

    In this study the soil/vegetation/atmosphere-model based on the formulation of Deardorff was refined to hour basis and applied to a field in Vihti. The effect of model parameters on model results (energy fluxes, temperatures) was also studied as well as the effect of atmospheric conditions. The estimation of atmospheric conditions on the soil-vegetation system as well as an estimation of the effect of vegetation parameters on the atmospheric climate was estimated. Areal surface fluxes, temperatures and moistures were also modelled for some river basins in southern Finland. Land-use and soil parameterisation was developed to include properties and yearly variation of all vegetation and soil types. One classification was selected to describe the hydrothermal properties of the soils. Evapotranspiration was verified against the water balance method

  14. Atmospheric corrosion in nuclear waste storage

    International Nuclear Information System (INIS)

    The following topics were dealt with: storage of conditioned radioactive wastes in metallic containers, atmospheric corrosion effects, long-term behavior prediction, numerical modelling of surface corrosion effects under thermohygrometric fluctuations according ISO/DIS 9223

  15. Containment Atmosphere Response (CAR) program status report

    International Nuclear Information System (INIS)

    The report contains a technical summary of the work performed on the chemical response of HTGR containment atmosphere during accidents such as core heat-up, steam ingress, and air ingress. Methods were developed and analytical models incorporated into existing and new computer programs. For the mixing and chemical behavior of combustible gases released into the containment atmosphere, a computer program based on the existing CNTB computer program for partial mixing in dry containment atmospheres at General Atomic (GA) was developed. An air ingress model was incorporated into the OXIDE-3 computer program to achieve coupling between the chemical reaction of air in the core and the containment response to the release of combustible gases from the prestressed concrete reactor vessel (PCRV). For the release of combustible particles into the containment atmosphere a new computer program (SILT) was developed for the prediction of the effects of combustion on containment integrity for a given concentration of carbon dust

  16. Thermal atmosphere of a black hole

    International Nuclear Information System (INIS)

    Black-hole atmospheres and their thermodynamic properties are explored quantitatively, using a membrane paradigm that includes a 3+1 formalism which splits space-time coordinates into a family of three-dimensional spacelike hypersurfaces and one-dimensional time. The means by which black holes retain their thermal atmosphere and avoid rapid evaporation are examined. Quantum mechanical probability distributions are presented for fiducial observers (FIDO) within a perfectly thermal atmosphere, and deviations from perfect thermality are discussed. Four types of modes of classical or quantized fields around a black hole are introduced (IN, UP, superradiant, and nonsuperradiant) and are used to describe interactions of the atmosphere with the external universe. Attention is also given to the statistical-mechanical origin of black-hole entropy, and a second law of thermodynamics is derived for a slowly evolving black hole using statistical-mechanics methods

  17. Atmospheric chemistry: The return of ethane

    Science.gov (United States)

    Hakola, Hannele; Hellén, Heidi

    2016-07-01

    Ethane emissions can lead to ozone pollution. Measurements at 49 sites show that long-declining atmospheric ethane concentrations started rising in 2010 in the Northern Hemisphere, largely due to greater oil and gas production in the USA.

  18. Single Event Effects: Space and Atmospheric Environments

    Science.gov (United States)

    Barth, Janet L.

    2003-01-01

    The paper discusses the following: 1. Sun-Earth connections. 2. Heavy ions: galactic cosmic rays; solar particle events. 3. Protons: solar particle events; trapped. 4. Atmospheric neutrons. 5. Summary.

  19. Optical Intensity Interferometry through Atmospheric Turbulence

    CERN Document Server

    Tan, Peng Kian; Kurtsiefer, Christian

    2015-01-01

    Conventional ground-based astronomical observations suffer from image distortion due to atmospheric turbulence. This can be minimized by choosing suitable geographic locations or adaptive optical techniques, and avoided altogether by using orbital platforms outside the atmosphere. One of the promises of optical intensity interferometry is its independence from atmospherically induced phase fluctuations. By performing narrowband spectral filtering on sunlight and conducting temporal intensity interferometry using actively quenched avalanche photon detectors (APDs), the Solar $g^{(2)}(\\tau)$ signature was directly measured. We observe an averaged photon bunching signal of $g^{(2)}(\\tau) = 1.693 \\pm 0.003$ from the Sun, consistently throughout the day despite fluctuating weather conditions, cloud cover and elevation angle. This demonstrates the robustness of the intensity interferometry technique against atmospheric turbulence and opto-mechanical instabilities, and the feasibility to implement measurement scheme...

  20. Earth's Climate: The Ocean-Atmosphere Interaction

    Science.gov (United States)

    Lifland, Jonathan

    2004-11-01

    A new AGU book, Earth's Climate: The Ocean-Atmosphere Interaction, edited by Chunzai Wang, Shang-Ping Xie, and James A. Carton, presents current observations, theories, and models of ocean-atmosphere interaction that helps shape climate and its variations over the global ocean. The book represents the climate community's first effort to summarize the modern science of ocean-atmosphere interaction and the roles that the interaction play in climate variability in the Pacific, Atlantic, and Indian Oceans as well as interactions across basins and between the tropics and extratropics. In this issue, Eos talks with lead editor Chunzai Wang. Wang is a research oceanographer at the Physical Oceanography Division of the National Oceanic and Atmospheric Administration's Atlantic Oceanographic and Meteorological Laboratory, in Miami, Florida.

  1. An Updated Analysis on Atmospheric Neutrinos

    CERN Document Server

    González-Garciá, M Concepción; Peres, O L G; Stanev, T; Valle, José W F

    1997-01-01

    We have reanalysed the atmospheric neutrino data including new results from Super-Kamiokande and Soudan-II experiments, under the assumption of two-flavor neutrino oscillation. We present the allowed region of oscillation parameters for the $\

  2. Methane present in an extrasolar planet atmosphere

    CERN Document Server

    Swain, Mark R; Tinetti, Giovanna

    2008-01-01

    Molecules present in exoplanetary atmospheres are expected to strongly influence the atmospheric radiation balance, trace dynamical and chemical processes, and indicate the presence of disequilibrium effects. Since molecules have the potential to reveal the exoplanet atmospheric conditions and chemistry, searching for them is a high priority. The rotational-vibrational transition bands of water, carbon monoxide, and methane are anticipated to be the primary sources of non-continuum opacity in hot-Jovian planets. Since these bands overlap in wavelength, and the corresponding signatures from them are weak, decisive identification requires precision infrared spectroscopy. Here we report on a near-infrared transmission spectrum of the planet HD 189733b showing the presence of methane. Additionally, a resolved water-vapour band at 1.9 microns confirms the recent claim of water in this object. On thermochemical grounds, carbon-monoxide is expected to be abundant in the upper atmosphere of hot-Jovian exoplanets; thu...

  3. Atmospheric neutrinos and discovery of neutrino oscillations

    International Nuclear Information System (INIS)

    Neutrino oscillation was discovered through studies of neutrinos produced by cosmic-ray interactions in the atmosphere. These neutrinos are called atmospheric neutrinos. They are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith-angle and energy dependent deficit of muon-neutrino events. Neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. Neutrino oscillations imply that neutrinos have small but non-zero masses. The small neutrino masses have profound implications to our understanding of elementary particle physics and the Universe. This article discusses the experimental discovery of neutrino oscillations. (author)

  4. Formulations of moist thermodynamics for atmospheric modelling

    CERN Document Server

    Marquet, Pascal

    2015-01-01

    Internal energy, enthalpy and entropy are the key quantities to study thermodynamic properties of the moist atmosphere, because they correspond to the First (internal energy and enthalpy) and Second (entropy) Laws of thermodynamics. The aim of this chapter is to search for analytical formulas for the specific values of enthalpy and entropy and for the moist-air mixture composing the atmosphere. The Third Law of thermodynamics leads to the definition of absolute reference values for thermal enthalpies and entropies of all atmospheric species. It is shown in this Chapter 22 that it is possible to define and compute a general moist-air entropy potential temperature, which is really an equivalent of the moist-air specific entropy in all circumstances (saturated, or not saturated). Similarly, it is shown that it is possible to define and compute the moist-air specific enthalpy, which is different from the thermal part of what is called Moist-Static-Energy in atmospheric studies.

  5. Pierre Auger Atmosphere-Monitoring Lidar System

    CERN Document Server

    Filipcic, A; Veberic, D; Zavrtanik, D; Zavrtanik, M; Chiosso, M; Mussa, R; Sequeiros, G; Mostafa, M A; Roberts, M D

    2003-01-01

    The fluorescence-detection techniques of cosmic-ray air-shower experiments require precise knowledge of atmospheric properties to reconstruct air-shower energies. Up to now, the atmosphere in desert-like areas was assumed to be stable enough so that occasional calibration of atmospheric attenuation would suffice to reconstruct shower profiles. However, serious difficulties have been reported in recent fluorescence-detector experiments causing systematic errors in cosmic ray spectra at extreme energies. Therefore, a scanning backscatter lidar system has been constructed for the Pierre Auger Observatory in Malargue, Argentina, where on-line atmospheric monitoring will be performed. One lidar system is already deployed at the Los Leones fluorescence detector site and the second one is currently (April 2003) under construction at the Coihueco site. Next to the established ones, a novel analysis method with assumption on horizontal invariance, using multi-angle measurements is shown to unambiguously measure optica...

  6. South America Land-Atmosphere Coupling Strength

    Science.gov (United States)

    de Mattos, J. Z.; Goncalves, L.; Herdies, D. L.

    2013-05-01

    This study examines the land-atmosphere coupling strength during summer over subregions of the South America based on simulations made with the Atmospheric Global Circulation Model (AGCM) of the INPE/CPTEC coupled with the simplified simple biosphere model (SsiB). The coupling strength is evaluated by the ability of subsurface soil wetness to affect locally the time series of precipitation. We follow the protocols of the Global Land-Atmosphere Coupling Experiment (GLACE) to measure the strenght of the land-atmosphere coupling. Over South America are found two main regions of strong coupling: 1) the La Plata Basin and 2) the Northeastern of Brazil. Some studies suggest that this regions are hotspot due to evapotranspiration recycling. Additional experiments, with different convective parameterization and with constrains in the surface soilmoisture, in which we isolate the AGCM as the principal source of the sensitivity of precipitation to land surface states were made.

  7. Low Temperature Atmospheric Pressure Plasma Sterilization Shower

    Science.gov (United States)

    Gandhiraman, R. P.; Beeler, D.; Meyyappan, M.; Khare, B. N.

    2012-10-01

    Low-temperature atmospheric pressure plasma sterilization shower to address both forward and backward biological contamination issues is presented. The molecular effects of plasma exposure required to sterilize microorganisms is also analysed.

  8. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line...

  9. Atmospheric Heat Redistribution on Hot Jupiters

    CERN Document Server

    Perez-Becker, Daniel

    2013-01-01

    Infrared lightcurves of transiting hot Jupiters present a trend in which the atmospheres of the hottest planets are less efficient at redistributing the stellar energy absorbed on their daysides---and thus have a larger day-night temperature contrast---than colder planets. No predictive atmospheric model has been published that identifies which dynamical mechanisms determine the atmospheric heat redistribution efficiency on tidally locked exoplanets. Here we present a two-layer shallow water model of the atmospheric dynamics on synchronously rotating planets that explains the observed trend. Our model shows that planets with weak friction and weak irradiation exhibit a banded zonal flow with minimal day-night temperature differences, while models with strong irradiation and/or strong friction exhibit a day-night flow pattern with order-unity fractional day-night temperature differences. To interpret the model, we develop a scaling theory that shows that the timescale for gravity waves to propagate horizontall...

  10. Fundamentals of Atmospheric Physics for Engineering

    CERN Document Server

    Cionco, Rodolfo G

    2012-01-01

    We present the proposal of an elective for engineering courses, designed to train professionals with a solid foundation in Physics of the Atmosphere interested in environmental and sustainability issues broadly. We propose four chapters that contain a variety of topics but strongly interrelated, which correspond to three main areas: nature of the atmosphere and meteorology relevant to contaminant transport, the dispersion of air pollutants and climate in general. We conclude that it is possible train engineers who understand the basic mechanisms that led to the current atmosphere, atmospheric processes related to local and global climate, the dispersion of air pollutants and key concepts such as solar activity, climatic change and climatic variability, even in one semester. It also discusses the relationship with other subjects and proposes and illustrates a method of course approval based on the performance of work directly applicable to engineering problems.

  11. Mars Molniya Orbit Atmospheric Resource Mining

    Science.gov (United States)

    Mueller, Robert P.; Braun, Robert D.; Sibille, Laurent; Sforzo, Brandon; Gonyea, Keir; Ali, Hisham

    2016-01-01

    This NIAC (NASA Advanced Innovative Concepts) work will focus on Mars and will build on previous efforts at analyzing atmospheric mining at Earth and the outer solar system. Spacecraft systems concepts will be evaluated and traded, to assess feasibility. However the study will primarily examine the architecture and associated missions to explore the closure, constraints and critical parameters through sensitivity studies. The Mars atmosphere consists of 95.5 percent CO2 gas which can be converted to methane fuel (CH4) and Oxidizer (O2) for chemical rocket propulsion, if hydrogen is transported from electrolyzed water on the Mars surface or from Earth. By using a highly elliptical Mars Molniya style orbit, the CO2 atmosphere can be scooped, ram-compressed and stored while the spacecraft dips into the Mars atmosphere at periapsis. Successive orbits result in additional scooping of CO2 gas, which also serves to aerobrake the spacecraft, resulting in a decaying Molniya orbit.

  12. Study of atmospheric pressure chemical vapor deposition by using a double discharge system for SiOx thin-film deposition with a HMDS/Ar/He/O2 gas mixture

    International Nuclear Information System (INIS)

    SiOx thin films were deposited at atmospheric pressure by using a double discharge system composed of a remote-type dielectric barrier discharge (DBD) formed above the substrate and a direct-type DBD formed by applying an AC power to the substrate with a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar. Instead of using a single DBD, the use of the double discharge system not only showed higher SiOx thin film deposition rates but also produced fewer impurities in the deposited SiOx thin film. The improvement was partially related to the increased gas dissociation near the substrate through the direct-type DBD and to the remote-type DBD. A 7-kV, 30-kHz AC voltage was applied to the remote-type DBD and a 5-kV, 20-kHz AC voltage was applied to the direct-type DBD, with a gas mixture of HMDS (400 sccm)/O2 (20 slm)/He (5 slm)/Ar (3 slm). As a result, a SiOx deposition rate of 58.29 nm/scan could be obtained while moving the substrate at a speed of 0.25 meter/min.

  13. Monitoring geologically stored carbon using atmospheric techniques

    International Nuclear Information System (INIS)

    Full text: Geosequestration (carbon capture and underground storage) is planned as a major global emissions reduction measure and is an essential part of several low C02 emission energy technologies. The potential escape of the geologically stored C02 to the atmosphere is one of the main concerns of project operators, regulators (including carbon accounting) and the public. Although rates of escape large enough to endanger health and safety are extremely unlikely, low leak rates could reduce the effectiveness of geosequestration in controlling emissions. Monitoring geosequestration sites will be a requirement and atmospheric monitoring will be part of an overall package, together with geophysical, geochemical, and hydrological techniques. Atmospheric monitoring of a C02 storage site will provide advantages such as relatively low cost and minimal intervention but also presents challenges because of the typically high and variable concentrations and fluxes of C02 in the atmosphere. Our modelling of hypothetical leaks from C02 storage and dispersion into the atmosphere suggests that identifying and quantifying emissions to the atmosphere may be possible with a combination of atmospheric techniques. These include the continuous and precise monitoring of C02, naturally occurring tracers such as C02 isotopes, and introduced tracers, together with the measurement and modeling of transport and C02 fluxes, over several special scales. An atmospheric monitoring strategy incorporating these techniques has been deployed at the C02CRC's Otway Basin Pilot Project in Victoria. This is Australia's first geosequestration project and the first in the world to include a comprehensive atmospheric scheme within its monitoring and verification program. The C02CRC plans to inject about 100,000 tonnes of C02 from a natural geological accumulation into a depleted natural gas reservoir over a period of about two years, observe the behavior of C02 in the subsurface and monitor intensively

  14. Isotopes in the Arctic atmospheric water cycle

    OpenAIRE

    Bonne, Jean-Louis; Werner, Martin; Meyer, Hanno; Kipfstuhl, Sepp; Rabe, Benjamin; Behrens, Melanie; Schönicke, Lutz; Steen-Larsen, Hans Christian; Masson-Delmotte, Valérie

    2016-01-01

    The ISO-ARC project aims at documenting the Arctic atmospheric hydrological cycle, by assessing the imprint of the marine boundary conditions (e.g. temperature variations, circulation changes, or meltwater input) to the isotopic composition of the atmospheric water cycle (H218O and HDO) with a focus on North Atlantic and Arctic oceans. For this purpose, two continuous monitoring water vapour stable isotopes cavity ring-down spectrometers have been installed in July 2015: on-boar...

  15. Gas fired boilers and atmospheric pollution

    International Nuclear Information System (INIS)

    A general analysis concerning atmospheric pollution is presented: chemical composition and vertical distribution of atmosphere and pollutants, chemical reactions, ozone destruction and production cycles, COx, NOx and SOx pollutions. The gas fired boiler number and repartition in France are presented and the associated pollution is analyzed (CO2, CO, NOx) and quantified. Various pollution control technics concerning gas fired boiler pollutants are described and a pollution criterion for clean gas fired generators is proposed

  16. Radiative transfer in the cloudy atmosphere

    OpenAIRE

    Mayer B.

    2009-01-01

    Radiative transfer in clouds is a challenging task, due to their high spatial and temporal variability which is unrivaled by any other atmospheric species. Clouds are among the main modulators of radiation along its path through the Earth’s atmosphere. The cloud feedback is the largest source of uncertainty in current climate model predictions. Cloud observation from satellites, on a global scale, with appropriate temporal and spatial sampling is therefore one of the top aims of current Earth...

  17. Effect of Atmospheric Ions on Interfacial Water

    OpenAIRE

    Chien-Chang Kurt Kung; Pollack, Gerald H.

    2014-01-01

    The effect of atmospheric positivity on the electrical properties of interfacial water was explored. Interfacial, or exclusion zone (EZ) water was created in the standard way, next to a sheet of Nafion placed horizontally at the bottom of a water-filled chamber. Positive atmospheric ions were created from a high voltage source placed above the chamber. Electrical potential distribution in the interfacial water was measured using microelectrodes. We found that beyond a threshold, the positive ...

  18. Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes

    OpenAIRE

    Albuquerque, Ivone F. M.; Smoot, George F.

    2001-01-01

    Neutrino telescopes with large detection volumes can demonstrate that the current indications of neutrino oscillation are correct or if a better description can be achieved with non-standard alternatives. Observations of contained muons produced by atmospheric neutrinos can better constrain the allowed region for oscillations or determine the relevant parameters of non-standard models. We analyze the possibility of neutrino telescopes measuring atmospheric neutrino oscillations. We suggest ad...

  19. Atmospheric plasma processes for environmental applications

    OpenAIRE

    Shapoval, Volodymyr

    2012-01-01

    Plasma chemistry is a rapidly growing field which covers applications ranging from technological processing of materials, including biological tissues, to environmental remediation and energy production. The so called atmospheric plasma, produced by electric corona or dielectric barrier discharges in a gas at atmospheric pressure, is particularly attractive for the low costs and ease of operation and maintenance involved. The high concentrations of energetic and chemically active species (e.g...

  20. Atmospheric freeze drying assisted by power ultrasound

    OpenAIRE

    Santacatalina Bonet, Juan Vicente; Carcel Carrión, Juan Andrés; García Pérez, José Vicente; Mulet Pons, Antonio; Simal, S.

    2012-01-01

    [EN] Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that pur...

  1. Evaluation of atmospheric corrosion in Orizaba, Mexico

    OpenAIRE

    J. L. RAMÍREZ-REYES; J. URUCHURTU-CHAVARÍN; J. Genescá; R. Longoria-Ramírez

    2012-01-01

    This study evaluated the atmospheric aggressiveness in the city of Orizaba, Veracruz, Mexico, as part of the Atmospheric corrosiveness map of the state of Veracruz project, developed by Universidad Veracruzana from 2007 to 2008. The corrosiveness in marine, industrial and rural environments was determined with the standard method of bolt and wire, and the corrosion levels throughout flat samples of mild steel, galvanized steel, copper and aluminum in accordance to ISO 9223. The corrosion prod...

  2. Marine atmospheric corrosion of carbon steels

    OpenAIRE

    Morcillo, Manuel; Alcántara, Jenifer; Díaz, Iván; Chico, Belén; Simancas, Joaquín; de la Fuente, Daniel

    2015-01-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products...

  3. 10Be production calculations in the atmosphere

    International Nuclear Information System (INIS)

    Cosmic rays (CRs) interacting with the Earth's atmosphere produce a cascade of secondary particles and cosmogenic nuclides. Cosmogenic nuclides itself are stored in natural archives such as ice cores and can therefore be measured by e.g. accelerator mass spectrometry (AMS). Here we present our calculations of the cosmogenic radionuclide 10Be, which is produced by spallation reactions between secondary neutrons and protons and the atmospheric gases nitrogen and oxygen, using PLANETOCOSMICS, a GEANT4 based computer code (Desorgher[2006]).

  4. Wind-Induced Atmospheric Escape: Titan

    Science.gov (United States)

    Hartle, Richard; Johnson, Robert; Sittler, Edward, Jr.; Sarantos, Menelaos; Simpson, David

    2012-01-01

    Rapid thermospheric flows can significantly enhance the estimates of the atmospheric loss rate and the structure of the atmospheric corona of a planetary body. In particular, rapid horizontal flow at the exobase can increase the corresponding constituent escape rate. Here we show that such corrections, for both thermal and non-thermal escape, cannot be ignored when calculating the escape of methane from Titan, for which drastically different rates have been proposed. Such enhancements are also relevant to Pluto and exoplanets.

  5. Antropogen contamination of the earth atmosphere

    International Nuclear Information System (INIS)

    Among the antropogen contamination sources of the earth atmosphere the total beta activity of rain water, carbon 14 activity according to the annual rings of trees and the krypton 85 activity of the air were determined systematically for several years in Hungary. The data of aerial contamination due to atmospheric nuclear explosions and to the impact of nuclear facilities especially nuclear power plants and fuel reprocessing plants are discussed and demonstrated in graphs. (V.N.) 12 refs.; 7 figs

  6. Computational investigations of atmospheric pressure discharges

    OpenAIRE

    Iqbal, Muhammad Munawar

    2010-01-01

    This research work presents the numerical simulations of multispecies multi-dimensional fluid model of atmospheric pressure discharge. The semi-implicit sequential iterative scheme is used to solve the coupled system of plasma fluid model equations with a proper set of boundary conditions. A one- dimensional self consistent drift-diffusion fluid model is developed to investigate the characteristics of atmospheric pressure discharge in pure helium and He-N2 gases. The uniform atmos...

  7. Peer-Mentoring Program and Academic Atmosphere

    OpenAIRE

    Sri Endah Kusmartini; Tiur Simanjuntak

    2014-01-01

    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 sam...

  8. North Sea sensitivity to atmospheric forcing

    OpenAIRE

    Skogen, Morten D.; Drinkwater, Ken; Solfrid S. Hjøllo; Schrum, Corinna

    2011-01-01

    The sensitivity of North Sea physics and phytoplankton production to atmospheric forcing has been studied by performing perturbations of the atmospheric forcing fields through a number of model simulations. The perturbations are kept in the range of expected climate change, to give a first indication of the climate change impacts on regional systems. The model simulations suggest that an increase in air temperature and short wave radiation will increase sea surface temperature, while an incre...

  9. Impact of Amazonian deforestation on atmospheric chemistry

    OpenAIRE

    Ganzeveld, L.N.; Lelieveld, J.

    2004-01-01

    A single-column chemistry and climate model has been used to study the impact of deforestation in the Amazon Basin on atmospheric chemistry. Over deforested areas, daytime ozone deposition generally decreases strongly except when surface wetness decreases through reduced precipitation, whereas nocturnal soil deposition increases. The isoprene and soil nitric oxide emissions decrease although nitrogen oxide release to the atmosphere increases due to reduced canopy deposition. Deforestation als...

  10. Modelling the atmospheric chemistry of volcanic plumes

    OpenAIRE

    Surl, Luke

    2016-01-01

    Abstract Volcanoes are the principal way by which volatiles are transferred from the solid Earth to the atmosphere-hydrosphere system. Once released into the atmosphere, volcanic emissions rapidly undergo a complex series of chemical reactions. This thesis seeks to further the understanding of such processes by both observation and numerical modelling. I have adapted WRF-Chem to model passive degassing from Mount Etna, the chemistry of its plume, and its influence on the ...

  11. Photochemical processing of aqueous atmospheric brown carbon

    Science.gov (United States)

    Zhao, R.; Lee, A. K. Y.; Huang, L.; Li, X.; Yang, F.; Abbatt, J. P. D.

    2015-06-01

    Atmospheric brown carbon (BrC) is a collective term for light absorbing organic compounds in the atmosphere. While the identification of BrC and its formation mechanisms is currently a central effort in the community, little is known about the atmospheric removal processes of aerosol BrC. As a result, we report on a series of laboratory studies of photochemical processing of BrC in the aqueous phase, by direct photolysis and OH oxidation. Solutions of ammonium sulfate mixed with glyoxal (GLYAS) or methylglyoxal (MGAS) are used as surrogates for a class of secondary BrC mediated by imine intermediates. Three nitrophenol species, namely 4-nitrophenol, 5-nitroguaiacol and 4-nitrocatechol, were investigated as a class of water-soluble BrC originating from biomass burning. Photochemical processing induced significant changes in the absorptive properties of BrC. The imine-mediated BrC solutions exhibited rapid photo-bleaching with both direct photolysis and OH oxidation, with atmospheric half-lives of minutes to a few hours. The nitrophenol species exhibited photo-enhancement in the visible range during direct photolysis and the onset of OH oxidation, but rapid photo-bleaching was induced by further OH exposure on an atmospheric timescale of an hour or less. To illustrate the atmospheric relevance of this work, we also performed direct photolysis experiments on water-soluble organic carbon extracted from biofuel combustion samples and observed rapid changes in the optical properties of these samples as well. Overall, these experiments indicate that atmospheric models need to incorporate representations of atmospheric processing of BrC species to accurately model their radiative impacts.

  12. Biopreservation in modified atmosphere packaged vegetables.

    OpenAIRE

    Bennik, M. H. J.

    1997-01-01

    Recent trends in food preservation are the use of mild preservation techniques, such as modified atmosphere (MA) packaging and refrigeration, to prolong the shelflife of foods without affecting the fresh character of the product. This has resulted in the development of a new generation of chill stored, minimally processed foods, such as vegetables that are packaged under reduced oxygen (0 2 ) and elevated carbon dioxide (C0 2 ) concentrations. These gas atmospheres in combination with refrige...

  13. Upper Atmosphere Humidity Measurement with Drycap Sensor

    OpenAIRE

    Lehtola, Terhi Johanna

    2014-01-01

    Atmospheric water vapor is a significant greenhouse gas. To gain proper understanding of the impact of water vapor on the climate, atmospheric water vapor profiles should be measured with high precision and accuracy. Due to challenging environmental conditions including extremely low temperatures and humidity concentrations, few research grade instruments are capable of measuring humidity accurately in upper troposphere and stratosphere. Laborious utilization or inadequate resolution of the e...

  14. Atmospheric trace gas measurements in the tropics

    OpenAIRE

    Petersen, Anna Katinka

    2009-01-01

    Fourier Transform Infrared (FTIR) spectrometry has been used for ground-based solar absorption, laboratory and flux measurements, to study the atmospheric composition, as well as physical and chemical processes in the atmosphere.The solar absorption FTIR measurements have been performed in Paramaribo, Suriname (5.8 N, 55.2 W) between September 2004 and November 2007 and represent the first remote sensing measurements in the inner tropics over severalyears. These measurements are of great impo...

  15. Atmospheric forcing of sulphate in speleothem carbonate.

    OpenAIRE

    Peter M. Wynn; Fairchild, Ian J.; Baker, A.; Frisia, S. R.; Borsato, A.; R. Miorandi

    2006-01-01

    Sulphur emitted into the atmosphere from anthropogenic combustion of fossil fuels has played a dramatic role in moderating climatic change. Trace amounts of sulphur in calcite speleothems suggest that stalagmites may act as archives of sulphur deposition, thereby recording aspects of atmospheric variability in sulphur content in mid-latitude locations. Stalagmites obtained from a variety of sites with proportions of sulphur from different sources display concentrations ranging from 15 to 200 ...

  16. FMCW Radar Performance for Atmospheric Measurements

    Directory of Open Access Journals (Sweden)

    T. Ince

    2010-04-01

    Full Text Available Frequency-modulated continuous-wave radars (FMCW have been used in the investigation of the atmosphere since the late 1960’s. FMCW radars provide tremendous sensitivity and spatial resolution compared to their pulsed counterparts and are therefore attractive for clear-air remote-sensing applications. However, these systems have some disadvantages and performance limitations that have prevented their widespread use by the atmospheric science community. In this study, system performance of atmospheric FMCW radar is analyzed and some measurement limitations for atmospheric targets are discussed. The effects of Doppler velocities and spectral widths on radar performance, radar’s near-field operation, and parallax errors for two-antenna radar systems are considered. Experimental data collected by the highresolution atmospheric FMCW radar is used to illustrate typical performance qualitatively based on morphological backscattered power information. A post-processing based on single-lag covariance differences between the Bragg and Rayleigh echo is applied to estimate clear-air component from refractive index turbulence and perform quantitative analysis of FMCW radar reflectivity from atmospheric targets.

  17. Worldwide trend of atmospheric mercury since 1995

    Directory of Open Access Journals (Sweden)

    F. Slemr

    2011-01-01

    Full Text Available Concern about the adverse effects of mercury on human health and ecosystems has led to tightening emission controls since the mid 1980s. But the resulting mercury emissions reductions in many parts of the world are believed to be offset or even surpassed by the increasing emissions in rapidly industrializing countries. Consequently, concentrations of atmospheric mercury are expected to remain roughly constant. Here we show that the worldwide atmospheric mercury concentration have decreased by about 20 to 38% since 1996 as indicated by long term monitoring at stations in the Southern and Northern Hemispheres combined with intermittent measurements of latitudinal distribution over the Atlantic Ocean. The total reduction of the atmospheric mercury burden of this magnitude within 14 yrs is unprecedented among most of atmospheric trace gases and is at odds with the current mercury emission inventories with nearly constant emissions over the period. It suggests a major shift in the biogeochemical cycle of mercury including oceans and soil reservoirs. Decreasing reemissions from the legacy of historical mercury emissions are the most likely explanation for this decline since the hypothesis of an accelerated oxidation rate of elemental mercury in the atmosphere is not supported by the observed trends of other trace gases. Consequently, models of the atmospheric mercury cycle have to include soil and ocean mercury pools and their dynamics to be able to make projections of future trends.

  18. Marine atmospheric corrosion of carbon steels

    International Nuclear Information System (INIS)

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  19. Comparative Planetary Atmospheres of the Galilean Satellites

    Science.gov (United States)

    Strobel, Darrell F.

    We know that each of the Galilean satellites of Jupiter has a tenuous atmosphere by terrestrial standards. Io has an SO2 atmosphere with column densities ~ 1016 cm-2 in the equatorial regions and at least an order of magnitude smaller densities in the polar regions. Europa and Ganymede have O2 atmospheres with column densities in the range of (1-10) x 1014 cm-2 whereas Callisto has an CO2 atmosphere of comparable column density. I will give exploratory comparisons of the composition of these atmospheres and their production and loss rates to estimate residence times of the dominant molecules. Based on measured and calculated ionospheric density profiles the ionospheric Pedersen and Hall conductances can be computed to estimate the strengths of their electrodynamic interactions with the Io plasma torus. As a result of these interactions large electric currents flow through their ionospheres (~ 106 A) accompanied by large Joule heating rates that can be the dominant heating mechanism of their atmospheres. Production mechanisms for HST/STIS observed UV airglow/auroras will be discussed in terms of neutral composition electron densities and temperatures necessary to achieve measured brightnesses.

  20. Mass loss from the atmosphere of Pluto

    Science.gov (United States)

    Liang, Mao-Chang; Yen, Chien-Chang; Taam, Ronald

    2015-11-01

    Molecules can escape readily from the atmosphere of Pluto. Hydrodynamic escape is a process that drives large scale escape. The process was generally believed to produce rather small isotopic fractionation. Here, we show that the escape highly fractionates the isotopic composition of nitrogen. The process preferentially selects lighter species, with an escape probability ~30% higher for the lighter isotopologue. This fractionation factor is higher than the fractionations occurring in most of known processes in modifying the distributions of molecules in the planetary atmospheres. The validity of the model can be tested against the upcoming data, mainly nitrogen abundance in the outer atmosphere of Pluto, from the New Horizons. The property of the selection can significantly modify the isotopic composition of the atmosphere, leaving the present-day atmosphere isotopically heavier than the ancient one. This also impacts the current view of the evolution of planetary atmospheres. Venus, for example, may not need that much mass loss, in order to explain the current D/H ratio.

  1. The Upper Atmosphere of HD17156b

    CERN Document Server

    Koskinen, T T; Miller, S

    2008-01-01

    HD17156b is a newly-found transiting extrasolar giant planet (EGP) that orbits its G-type host star in a highly eccentric orbit (e~0.67) with an orbital semi-major axis of 0.16 AU. Its period, 21.2 Earth days, is the longest among the known transiting planets. The atmosphere of the planet undergoes a 27-fold variation in stellar irradiation during each orbit, making it an interesting subject for atmospheric modelling. We have used a three-dimensional model of the upper atmosphere and ionosphere for extrasolar gas giants in order to simulate the progress of HD17156b along its eccentric orbit. Here we present the results of these simulations and discuss the stability, circulation, and composition in its upper atmosphere. Contrary to the well-known transiting planet HD209458b, we find that the atmosphere of HD17156b is unlikely to escape hydrodynamically at any point along the orbit, even if the upper atmosphere is almost entirely composed of atomic hydrogen and H+, and infrared cooling by H3+ ions is negligible...

  2. Atmospheric Neutrinos in the MINOS Far Detector

    Energy Technology Data Exchange (ETDEWEB)

    Howcroft, Caius L.F.

    2004-12-01

    The phenomenon of flavour oscillations of neutrinos created in the atmosphere was first reported by the Super-Kamiokande collaboration in 1998 and since then has been confirmed by Soudan 2 and MACRO. The MINOS Far Detector is the first magnetized neutrino detector able to study atmospheric neutrino oscillations. Although it was designed to detect neutrinos from the NuMI beam, it provides a unique opportunity to measure the oscillation parameters for neutrinos and anti-neutrinos independently. The MINOS Far Detector was completed in August 2003 and since then has collected 2.52 kton-years of atmospheric data. Atmospheric neutrino interactions contained within the volume of the detector are separated from the dominant background from cosmic ray muons. Thirty seven events are selected with an estimated background contamination of less than 10%. Using the detector's magnetic field, 17 neutrino events and 6 anti-neutrino events are identified, 14 events have ambiguous charge. The neutrino oscillation parameters for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} are studied using a maximum likelihood analysis. The measurement does not place constraining limits on the neutrino oscillation parameters due to the limited statistics of the data set analysed. However, this thesis represents the first observation of charge separated atmospheric neutrino interactions. It also details the techniques developed to perform atmospheric neutrino analyses in the MINOS Far Detector.

  3. Analysis of coastal atmospheric stability schemes

    International Nuclear Information System (INIS)

    The delta temperature and sigma theta methods do not correlate well in the determination of atmospheric stability. However, the two values were within one stability class of each other more than 80 per cent of the time. In its present form, the wind speed ratio method cannot be used for determination of atmospheric stability at the two coastal nuclear power plants that were examined. Modified sigma theta (MST) is a small improvement over the conventional sigma theta method. However, MST is still not an acceptable substitute for the temperature difference method in the determination of atmospheric stability. Under conditions which require the use of a backup meteorological monitoring system, stability conditions observed at one plant cannot be used as an indicator of stability at the other plant without the development of a complex correlation scheme. This study has demonstrated the noncomparability among various systems for determining atmospheric stability. The results support the conclusions drawn by other investigators. Future work should be concentrated on a detailed examination of the relationship between the atmospheric stability schemes and the strength of the lake breeze (based on the difference between lake temperature and land temperature) for lake breeze cases. The use of Monin-Obukhov length as an atmospheric stability indicator should also be explored

  4. Marine atmospheric corrosion of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Morcillo, M.; Alcantara, J.; Diaz, I.; Chico, B.; Simancas, J.; Fuente, D. de la

    2015-07-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  5. Triton's surface-atmosphere energy balance

    Science.gov (United States)

    Stansberry, J.A.; Yelle, R.V.; Lunine, J.I.; McEwen, A.S.

    1992-01-01

    We explore the energetics of Triton's surface-atmosphere system using a model that includes the turbulent transfer of sensible heat as well as insolation, reradiation, and latent heat transport. The model relies on a 1?? by 1?? resolution hemispheric bolometric albedo map of Triton for determining the atmospheric temperature, the N2 frost emissivity, and the temperatures of unfrosted portions of the surface consistent with a frost temperature of ???38 K. For a physically plausible range of heat transfer coefficients, we find that the atmospheric temperature roughly 1 km above the surface is approximately 1 to 3 K hotter than the surface. Atmospheric temperatures of 48 K suggested by early analysis of radio occultation data cannot be obtained for plausible values of the heat transfer coefficients. Our calculations indicate that Triton's N2 frosts must have an emissivity well below unity in order to have a temperature of ???38 K, consistent with previous results. We also find that convection over small hot spots does not significantly cool them off, so they may be able to act as continous sources of buoyancy for convective plumes, but have not explored whether the convection is vigorous enough to entrain particulate matter thereby forming a dust devil. Our elevated atmospheric temperatures make geyser driven plumes with initial upward velocities ???10 m s-1 stagnate in the lower atmosphere. These "wimpy" plumes provide a possible explanation for Triton's "wind streaks.". ?? 1992.

  6. Pluto's lower atmosphere structure and methane abundance from high-resolution spectroscopy and stellar occultations

    OpenAIRE

    Lellouch, E.; Sicardy, B.; De Bergh, Catherine; Käufl, H.-U.; Kassi, Samir; Campargue, Alain

    2009-01-01

    International audience Context. Pluto possesses a thin atmosphere, primarily composed of nitrogen, in which the detection of methane has been reported. Aims. The goal is to constrain essential but so far unknown parameters of Pluto's atmosphere such as the surface pressure, lower atmosphere thermal stucture, and methane mixing ratio. Methods. We use high-resolution spectroscopic observations of gaseous methane, and a novel analysis of occultation light-curves. Results. We show that (i) Plu...

  7. Development of an RF cavity for an atmospheric scanning positron microscope

    International Nuclear Information System (INIS)

    An atmospheric scanning positron microscope has been developed for obtaining a positron annihilation imaging of a sample mounted in the atmosphere. Then, positron microbeam has to be accelerated up to 50-100 keV to extract it from the vacuum chamber to the atmosphere through a thin film. Therefore, we have developed an RF acceleration cavity and the single-gap type was fabricated as the first phase. (author)

  8. Enhancement of the light-scattering ability of Ga-doped ZnO thin films using SiOx nano-films prepared by atmospheric pressure plasma deposition system

    International Nuclear Information System (INIS)

    To enhance the light-trapping qualities of silicon thin-film solar cells, the use of transparent conductive oxide with high haze and high conductivity is essential. This study investigated an eco-friendly technique that used bilayer Ga-doped zinc oxide/SiOx films prepared with an atmospheric pressure plasma jet to achieve high haze and low resistivity. A minimum resistivity of 6.00 × 10−4 Ω·cm was achieved at 8 at.% gallium doping. Examination of X-ray diffraction spectra showed that increased film thickness led to increased carrier concentration in GZO bilayers. The optimal bilayer GZO film achieved considerably higher haze values in the visible and NIR regions, compared with Asahi U-type fluorine doped tin oxide. - Highlights: • Ga-doped ZnO (GZO) and SiOx deposited by atmospheric pressure plasma jet (APPJ) • Deposition uses a water-based precursor and low substrate temperature (< 150 °C). • SiOx buffer layers deposited by APPJ can control haze value of Ga-doped ZnO films. • GZO/SiOx achieved the resistivity of 6.00 × 10−4 Ω·cm and haze of 21.5% at 550 nm

  9. Atmosphere: An International and Interdisciplinary Scientific Open Access Journal

    OpenAIRE

    Daniela Jacob

    2010-01-01

    The new online, Open Access journal Atmosphere has been launched to present reviews, regular research papers, communications and short notes on atmospheric topics. These topics include experimental and theoretical work related to the physical atmosphere, such as turbulence, atmospheric flow, dynamic and physical processes and mechanisms, atmospheric chemistry, such as changes in atmospheric composition, including aerosols, ozone, air pollution, chemical weather, meteorology and scale interact...

  10. Comparing the Degree of Land-Atmosphere Interaction in Four Atmospheric General Circulation Models

    Science.gov (United States)

    Koster, Randal D.; Dirmeyer, Paul A.; Hahmann, Andrea N.; Ijpelaar, Ruben; Tyahla, Lori; Cox, Peter; Suarez, Max J.; Houser, Paul R. (Technical Monitor)

    2001-01-01

    Land-atmosphere feedback, by which (for example) precipitation-induced moisture anomalies at the land surface affect the overlying atmosphere and thereby the subsequent generation of precipitation, has been examined and quantified with many atmospheric general circulation models (AGCMs). Generally missing from such studies, however, is an indication of the extent to which the simulated feedback strength is model dependent. Four modeling groups have recently performed a highly controlled numerical experiment that allows an objective inter-model comparison of land-atmosphere feedback strength. The experiment essentially consists of an ensemble of simulations in which each member simulation artificially maintains the same time series of surface prognostic variables. Differences in atmospheric behavior between the ensemble members then indicates the degree to which the state of the land surface controls atmospheric processes in that model. A comparison of the four sets of experimental results shows that feedback strength does indeed vary significantly between the AGCMs.

  11. The Performance Improvement of N2 Plasma Treatment on ZrO2 Gate Dielectric Thin-Film Transistors with Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition IGZO Channel.

    Science.gov (United States)

    Wu, Chien-Hung; Huang, Bo-Wen; Chang, Kow-Ming; Wang, Shui-Jinn; Lin, Jian-Hong; Hsu, Jui-Mei

    2016-06-01

    The aim of this paper is to illustrate the N2 plasma treatment for high-κ ZrO2 gate dielectric stack (30 nm) with indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs). Experimental results reveal that a suitable incorporation of nitrogen atoms could enhance the device performance by eliminating the oxygen vacancies and provide an amorphous surface with better surface roughness. With N2 plasma treated ZrO2 gate, IGZO channel is fabricated by atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique. The best performance of the AP-PECVD IGZO TFTs are obtained with 20 W-90 sec N2 plasma treatment with field-effect mobility (μ(FET)) of 22.5 cm2/V-s, subthreshold swing (SS) of 155 mV/dec, and on/off current ratio (I(on)/I(off)) of 1.49 x 10(7). PMID:27427669

  12. Atmospheric confinement of jet streams on Uranus and Neptune.

    Science.gov (United States)

    Kaspi, Yohai; Showman, Adam P; Hubbard, William B; Aharonson, Oded; Helled, Ravit

    2013-05-16

    The observed cloud-level atmospheric circulation on the outer planets of the Solar System is dominated by strong east-west jet streams. The depth of these winds is a crucial unknown in constraining their overall dynamics, energetics and internal structures. There are two approaches to explaining the existence of these strong winds. The first suggests that the jets are driven by shallow atmospheric processes near the surface, whereas the second suggests that the atmospheric dynamics extend deeply into the planetary interiors. Here we report that on Uranus and Neptune the depth of the atmospheric dynamics can be revealed by the planets' respective gravity fields. We show that the measured fourth-order gravity harmonic, J4, constrains the dynamics to the outermost 0.15 per cent of the total mass of Uranus and the outermost 0.2 per cent of the total mass of Neptune. This provides a stronger limit to the depth of the dynamical atmosphere than previously suggested, and shows that the dynamics are confined to a thin weather layer no more than about 1,000 kilometres deep on both planets. PMID:23676751

  13. PCBs in the Arctic atmosphere: determining important driving forces using a global atmospheric transport model

    OpenAIRE

    Friedman, Carey L.; Selin, Noelle E

    2016-01-01

    We present a spatially and temporally resolved global atmospheric polychlorinated biphenyl (PCB) model, driven by meteorological data, that is skilled at simulating mean atmospheric PCB concentrations and seasonal cycles in the Northern Hemisphere midlatitudes and mean Arctic concentrations. However, the model does not capture the observed Arctic summer maximum in atmospheric PCBs. We use the model to estimate global budgets for seven PCB congeners, and we demonstrate that c...

  14. Air-sea interaction in tropical atmosphere: influence of ocean mixing on atmospheric processes

    OpenAIRE

    Baranowski, Dariusz B.

    2016-01-01

    One the major factors determining the development and evolution of atmospheric convection is the sea surface temperature and its variability. Results of this thesis show that state of atmospheric convection impacts the diurnal distribution of thermal energy in the upper ocean. Under calm and clear sky conditions a shallow warm layer of several meters depth develops on the surface of the ocean. This warm layer drives an anomalous flux from the ocean to the atmosphere. A novel Kelvin wave traje...

  15. Analytical investigation of the atmospheric radiation limits in semigray atmospheres in radiative equilibrium

    OpenAIRE

    Pujol i Sagaró, Toni; North, Gerald R.

    2003-01-01

    We model the wavelength-dependent absorption of atmospheric gases by assuming constant mass absorption coefficients in finite-width spectral bands. Such a semigray atmosphere is analytically solved by a discrete ordinate method. The general solution is analyzed for a water vapor saturated atmosphere that also contains a carbon dioxide-like absorbing gas in the infrared. A multiple stable equilibrium with a relative upper limit in the outgoing long-wave radiation is found. Differing from previ...

  16. Influence of thermal treatment in N{sub 2} atmosphere on chemical, microstructural and optical properties of indium tin oxide and nitrogen doped indium tin oxide rf-sputtered thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stroescu, H.; Anastasescu, M.; Preda, S.; Nicolescu, M.; Stoica, M. [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Stefan, N. [National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, RO-77125, Bucharest-Magurele (Romania); Kampylafka, V.; Aperathitis, E. [FORTH-IESL, Crete (Greece); Modreanu, M. [Tyndall National Institute, University College Cork, Cork (Ireland); Zaharescu, M. [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Gartner, M., E-mail: mgartner@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania)

    2013-08-31

    We report the influence of the normal thermal treatment (TT) and of rapid thermal annealing (RTA) on the microstructural, optical and electrical properties of indium tin oxide (ITO) and nitrogen doped indium tin oxide (ITO:N) thin films. The TT was carried out for 1 h at 400 °C and the RTA for 1 min up to 400 °C, both in N{sub 2} atmosphere. The ITO and ITO:N films were deposited by reactive sputtering in Argon, and respectively Nitrogen plasma, on Si with (100) and (111) orientation. The present study brings data about the microstructural and optical properties of ITO thin films with thicknesses around 300–400 nm. Atomic Force Microscopy analysis showed the formation of continuous and homogeneous films, fully covered by quasi-spherical shaped particles, with higher roughness values on Si(100) as compared to Si(111). Spectroscopic ellipsometry allowed the determination of film thickness, optical band gap as well as of the dispersion curves of n and k optical constants. X-ray diffraction analysis revealed the presence of diffraction peaks corresponding to the same nominal bulk composition of ITO, but with different intensities and preferential orientation depending on the substrate, atmosphere of deposition and type of thermal treatment. - Highlights: ► Stability of the films can be monitored by experimental ellipsometric spectra. ► The refractive index of indium tin oxide film on 0.3–30 μm range is reported. ► Si(100) substrate induces rougher film surfaces than Si(111). ► Rapid thermal annealing and normal thermal treatment lead to stable conductive film. ► The samples have a higher preferential orientation after rapid thermal annealing.

  17. Electrochemical protection of pointed metallic structures from atmospheric corrosion

    International Nuclear Information System (INIS)

    Efficiency of electrochemical protection (ECP) of steel against atmospheric corrosion under thin electrolyte films is investigated. It is shown that the zone of ECP action is restricted by a low conductivity of moisture films, occurring on metals under natural conditions. A method of increasing ECP efficiency by means of using electroconducting coatings applied to standard paint and varnish coatings, is proposed. 6 refs., 2 figs

  18. Copper Corrosion by Atmospheric Pollutants in the Electronics Industry

    OpenAIRE

    Benjamin Valdez Salas; Michael Schorr Wiener; Roumen Zlatev Koytchev; Gustavo López Badilla; Rogelio Ramos Irigoyen; Monica Carrillo Beltrán; Nicola Radnev Nedev; Mario Curiel Alvarez; Navor Rosas Gonzalez; Jose María Bastidas Rull

    2013-01-01

    Hydrogen sulphide (H2S) is considered one of the most corrosive atmospheric pollutants. It is a weak, diprotic, reducing acid, readily soluble in water and dispersed into the air by winds when emitted from natural, industrial, and anthropogenic sources. It is a pollutant with a high level of toxicity impairing human health and the environment quality. It attacks copper forming thin films of metallic sulphides or dendrite whiskers, which are cathodic to the metal substrate, enhancing corrosion...

  19. Atmospheric icing of structures: Observations and simulations

    Science.gov (United States)

    Ágústsson, H.; Elíasson, Á. J.; Thorsteins, E.; Rögnvaldsson, Ó.; Ólafsson, H.

    2012-04-01

    This study compares observed icing in a test span in complex orography at Hallormsstaðaháls (575 m) in East-Iceland with parameterized icing based on an icing model and dynamically downscaled weather at high horizontal resolution. Four icing events have been selected from an extensive dataset of observed atmospheric icing in Iceland. A total of 86 test-spans have been erected since 1972 at 56 locations in complex terrain with more than 1000 icing events documented. The events used here have peak observed ice load between 4 and 36 kg/m. Most of the ice accretion is in-cloud icing but it may partly be mixed with freezing drizzle and wet snow icing. The calculation of atmospheric icing is made in two steps. First the atmospheric data is created by dynamically downscaling the ECMWF-analysis to high resolution using the non-hydrostatic mesoscale Advanced Research WRF-model. The horizontal resolution of 9, 3, 1 and 0.33 km is necessary to allow the atmospheric model to reproduce correctly local weather in the complex terrain of Iceland. Secondly, the Makkonen-model is used to calculate the ice accretion rate on the conductors based on the simulated temperature, wind, cloud and precipitation variables from the atmospheric data. In general, the atmospheric model correctly simulates the atmospheric variables and icing calculations based on the atmospheric variables correctly identify the observed icing events, but underestimate the load due to too slow ice accretion. This is most obvious when the temperature is slightly below 0°C and the observed icing is most intense. The model results improve significantly when additional observations of weather from an upstream weather station are used to nudge the atmospheric model. However, the large variability in the simulated atmospheric variables results in high temporal and spatial variability in the calculated ice accretion. Furthermore, there is high sensitivity of the icing model to the droplet size and the possibility that

  20. MAVEN Observations of Atmospheric Loss at Mars

    Science.gov (United States)

    Curry, Shannon; Luhmann, Janet; Jakosky, Bruce M.; Brain, David; LeBlanc, Francis; Modolo, Ronan; Halekas, Jasper S.; Schneider, Nicholas M.; Deighan, Justin; McFadden, James; Espley, Jared R.; Mitchell, David L.; Connerney, J. E. P.; Dong, Yaxue; Dong, Chuanfei; Ma, Yingjuan; Cohen, Ofer; Fränz, Markus; Holmström, Mats; Ramstad, Robin; Hara, Takuya; Lillis, Robert J.

    2016-06-01

    The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has been making observations of the Martian upper atmosphere and its escape to space since November 2014. The subject of atmospheric loss at terrestrial planets is a subject of intense interest not only because of the implications for past and present water reservoirs, but also for its impacts on the habitability of a planet. Atmospheric escape may have been especially effective at Mars, relative to Earth or Venus, due to its smaller size as well as the lack of a global dynamo magnetic field. Not only is the atmosphere less gravitationally bound, but also the lack of global magnetic field allows the impinging solar wind to interact directly with the Martian atmosphere. When the upper atmosphere is exposed to the solar wind, planetary neutrals can be ionized and 'picked up' by the solar wind and swept away.Both neutral and ion escape have played significant roles the long term climate change of Mars, and the MAVEN mission was designed to directly measure both escaping planetary neutrals and ions with high energy, mass, and time resolution. We will present 1.5 years of observations of atmospheric loss at Mars over a variety of solar and solar wind conditions, including extreme space weather events. We will report the average ion escape rate and the spatial distribution of escaping ions as measured by MAVEN and place them in context both with previous measurements of ion loss by other spacecraft (e.g. Phobos 2 and Mars Express) and with estimates of neutral escape rates by MAVEN. We will then report on the measured variability in ion escape rates with different drivers (e.g. solar EUV, solar wind pressure, etc.) and the implications for the total ion escape from Mars over time. Additionally, we will also discuss the implications for atmospheric escape at exoplanets, particularly weakly magnetized planetary bodies orbiting M-dwarfs, and the dominant escape mechanisms that may drive atmospheric erosion in other