WorldWideScience

Sample records for strongly reducing atmosphere

  1. Spectroscopic Investigations of High-Power Laser Sparks in Gas Mixtures Containing Methane: A Laboratory Model of Energetic Events in Strongly Reduced Planetary Atmospheres

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Civiš, Martin; Rašín, R.; Kamas, Michal; Dryahina, Kseniya; Španěl, Patrik; Juha, Libor; Ferus, Martin

    2009-01-01

    Roč. 39, 3-4 (2009), s. 217-217 ISSN 0169-6149 R&D Projects: GA MŠk LC510; GA MŠk(CZ) LC528; GA ČR GA203/06/1278 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100523 Keywords : planetary atmosphere * lasers * spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.053, year: 2009

  2. Reducing Weak to Strong Bisimilarity in CCP

    Directory of Open Access Journals (Sweden)

    Andrés Aristizábal

    2012-12-01

    Full Text Available Concurrent constraint programming (ccp is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes evolve by posting and querying (partial information in a global medium. Bisimilarity is a standard behavioural equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for ccp, and a ccp partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimiliarity is a central behavioural equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity; a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for ccp. We give an alternative reduction from weak ccp bisimilarity to the strong one that allows us to use the ccp partition refinement algorithm for deciding this equivalence.

  3. Strong scintillations during atmospheric occultations Theoretical intensity spectra. [radio scattering during spacecraft occultations by planetary atmospheres

    Science.gov (United States)

    Hinson, D. P.

    1986-01-01

    Each of the two Voyager spacecraft launched in 1977 has completed a reconnaissance of the Jovian and Saturnian systems. In connection with occultation experiments, strong scintillations were observed. Further theoretical work is required before these scintillations can be interpreted. The present study is, therefore, concerned with the derivation of a theory for strong scattering during atmospheric occultation experiments, taking into account as fundamental quantity of interest the spatial spectrum (or spectral density) of intensity fluctuations. Attention is given to a theory for intensity spectra, and numerical calculations. The new formula derived for Phi-i accounts for strong scattering of electromagnetic waves during atmospheric occultations.

  4. Regionally strong feedbacks between the atmosphere and terrestrial biosphere

    Science.gov (United States)

    Green, Julia K.; Konings, Alexandra G.; Alemohammad, Seyed Hamed; Berry, Joseph; Entekhabi, Dara; Kolassa, Jana; Lee, Jung-Eun; Gentine, Pierre

    2017-06-01

    The terrestrial biosphere and atmosphere interact through a series of feedback loops. Variability in terrestrial vegetation growth and phenology can modulate fluxes of water and energy to the atmosphere, and thus affect the climatic conditions that in turn regulate vegetation dynamics. Here we analyse satellite observations of solar-induced fluorescence, precipitation, and radiation using a multivariate statistical technique. We find that biosphere-atmosphere feedbacks are globally widespread and regionally strong: they explain up to 30% of precipitation and surface radiation variance in regions where feedbacks occur. Substantial biosphere-precipitation feedbacks are often found in regions that are transitional between energy and water limitation, such as semi-arid or monsoonal regions. Substantial biosphere-radiation feedbacks are often present in several moderately wet regions and in the Mediterranean, where precipitation and radiation increase vegetation growth. Enhancement of latent and sensible heat transfer from vegetation accompanies this growth, which increases boundary layer height and convection, affecting cloudiness, and consequently incident surface radiation. Enhanced evapotranspiration can increase moist convection, leading to increased precipitation. Earth system models underestimate these precipitation and radiation feedbacks mainly because they underestimate the biosphere response to radiation and water availability. We conclude that biosphere-atmosphere feedbacks cluster in specific climatic regions that help determine the net CO2 balance of the biosphere.

  5. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 85; Issue 3. Reduced larval feeding rate is a strong evolutionary correlate of rapid development in Drosophila melanogaster. M. Rajamani N. Raghavendra ... Keywords. life-history evolution; development time; larval feeding rate; competition; tradeoffs; Drosophila melanogaster.

  6. Self-channeling of high-power laser pulses through strong atmospheric turbulence

    Science.gov (United States)

    Peñano, J.; Palastro, J. P.; Hafizi, B.; Helle, M. H.; DiComo, G. P.

    2017-07-01

    We present an unusual example of truly long-range propagation of high-power laser pulses through strong atmospheric turbulence. A form of nonlinear self-channeling is achieved when the laser power is close to the self-focusing power of air and the transverse dimensions of the pulse are smaller than the coherence diameter of turbulence. In this mode, nonlinear self-focusing counteracts diffraction, and turbulence-induced spreading is greatly reduced. Furthermore, the laser intensity is below the ionization threshold so that multiphoton absorption and plasma defocusing are avoided. Simulations show that the pulse can propagate many Rayleigh lengths (several kilometers) while maintaining a high intensity. In the presence of aerosols, or other extinction mechanisms that deplete laser energy, the pulse can be chirped to maintain the channeling.

  7. Strongly-Interacting Fermi Gases in Reduced Dimensions

    Science.gov (United States)

    2015-11-16

    12 2012): 0. doi: 10.1103/PhysRevA.86.063625 Allan Adams , Lincoln D Carr, Thomas Schäfer, Peter Steinberg, John E Thomas. Strongly correlated quantum...Physics (NCSU, 2013) Received Book Chapter TOTAL: PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: Discipline Willie Ong 1.00 Chingyun Cheng 0.50...PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: NAME Total Number: NAME Total Number: Willie Ong 1 PERCENT_SUPPORTEDNAME FTE Equivalent: Total

  8. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    Science.gov (United States)

    Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  9. Glacial ocean circulation and stratification explained by reduced atmospheric temperature.

    Science.gov (United States)

    Jansen, Malte F

    2017-01-03

    Earth's climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5-10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

  10. Formation of nucleobases in a Miller–Urey reducing atmosphere

    Czech Academy of Sciences Publication Activity Database

    Ferus, Martin; Pietrucci, F.; Saitta, A. M.; Knížek, Antonín; Kubelík, Petr; Ivanek, Ondřej; Shestivska, Violetta; Civiš, Svatopluk

    2017-01-01

    Roč. 114, č. 17 (2017), s. 4306-4311 ISSN 0027-8424 R&D Projects: GA MŠk LG15013; GA ČR(CZ) GA14-12010S; GA MŠk(CZ) LM2015083; GA MŠk(CZ) 7AMB16FR035 Institutional support: RVO:61388955 Keywords : origin of life * asteroid impact * reducing atmosphere Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 9.661, year: 2016

  11. Atmospheres and spectra of strongly magnetized neutron stars - II. The effect of vacuum polarization

    Science.gov (United States)

    Ho, Wynn C. G.; Lai, Dong

    2003-01-01

    We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B= 1014-1015 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy that depends on the plasma density. Vacuum polarization can also induce resonant conversion of photon modes via a mechanism analogous to the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism for neutrino oscillation. We construct atmosphere models in radiative equilibrium with an effective temperature of a few ×106 K by solving the full radiative transfer equations for both polarization modes in a fully ionized hydrogen plasma. We discuss the subtleties in treating the vacuum polarization effects in the atmosphere models and present approximate solutions to the radiative transfer problem which bracket the true answer. We show from both analytic considerations and numerical calculations that vacuum polarization produces a broad depression in the X-ray flux at high energies (a few keV <~E<~ a few tens of keV) as compared to models without vacuum polarization; this arises from the density dependence of the vacuum resonance feature and the large density gradient present in the atmosphere. Thus the vacuum polarization effect softens the high-energy tail of the thermal spectrum, although the atmospheric emission is still harder than the blackbody spectrum because of the non-grey opacities. We also show that the depression of continuum flux strongly suppresses the equivalent width of the ion cyclotron line and therefore makes the line more difficult to observe.

  12. Background levels of methane in Mars’ atmosphere show strong seasonal variations

    Science.gov (United States)

    Webster, Christopher R.; Mahaffy, Paul R.; Atreya, Sushil K.; Moores, John E.; Flesch, Gregory J.; Malespin, Charles; McKay, Christopher P.; Martinez, German; Smith, Christina L.; Martin-Torres, Javier; Gomez-Elvira, Javier; Zorzano, Maria-Paz; Wong, Michael H.; Trainer, Melissa G.; Steele, Andrew; Archer, Doug; Sutter, Brad; Coll, Patrice J.; Freissinet, Caroline; Meslin, Pierre-Yves; Gough, Raina V.; House, Christopher H.; Pavlov, Alexander; Eigenbrode, Jennifer L.; Glavin, Daniel P.; Pearson, John C.; Keymeulen, Didier; Christensen, Lance E.; Schwenzer, Susanne P.; Navarro-Gonzalez, Rafael; Pla-García, Jorge; Rafkin, Scot C. R.; Vicente-Retortillo, Álvaro; Kahanpää, Henrik; Viudez-Moreiras, Daniel; Smith, Michael D.; Harri, Ari-Matti; Genzer, Maria; Hassler, Donald M.; Lemmon, Mark; Crisp, Joy; Sander, Stanley P.; Zurek, Richard W.; Vasavada, Ashwin R.

    2018-06-01

    Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.

  13. Treating Sample Covariances for Use in Strongly Coupled Atmosphere-Ocean Data Assimilation

    Science.gov (United States)

    Smith, Polly J.; Lawless, Amos S.; Nichols, Nancy K.

    2018-01-01

    Strongly coupled data assimilation requires cross-domain forecast error covariances; information from ensembles can be used, but limited sampling means that ensemble derived error covariances are routinely rank deficient and/or ill-conditioned and marred by noise. Thus, they require modification before they can be incorporated into a standard assimilation framework. Here we compare methods for improving the rank and conditioning of multivariate sample error covariance matrices for coupled atmosphere-ocean data assimilation. The first method, reconditioning, alters the matrix eigenvalues directly; this preserves the correlation structures but does not remove sampling noise. We show that it is better to recondition the correlation matrix rather than the covariance matrix as this prevents small but dynamically important modes from being lost. The second method, model state-space localization via the Schur product, effectively removes sample noise but can dampen small cross-correlation signals. A combination that exploits the merits of each is found to offer an effective alternative.

  14. Effectiveness of Emission Controls to Reduce the Atmospheric Concentrations of Mercury.

    Science.gov (United States)

    Castro, Mark S; Sherwell, John

    2015-12-15

    Coal-fired power plants in the United States are required to reduce their emissions of mercury (Hg) into the atmosphere to lower the exposure of Hg to humans. The effectiveness of power-plant emission controls on the atmospheric concentrations of Hg in the United States is largely unknown because there are few long-term high-quality atmospheric Hg data sets. Here, we present the atmospheric concentrations of Hg and sulfur dioxide (SO2) measured from 2006 to 2015 at a relatively pristine location in western Maryland that is several (>50 km) kilometers downwind of power plants in Ohio, Pennsylvania, and West Virginia. Annual average atmospheric concentrations of gaseous oxidized mercury (GOM), SO2, fine particulate mercury (PBM2.5), and gaseous elemental mercury (GEM) declined by 75%, 75%, 43%, and 13%, respectively, and were strongly correlated with power-plant Hg emissions from the upwind states. These results provide compelling evidence that reductions in Hg emissions from power plants in the United States had their intended impact to reduce regional Hg pollution.

  15. Regional atmospheric budgets of reduced nitrogen over the British isles assessed using a multi-layer atmospheric transport model

    NARCIS (Netherlands)

    Fournier, N.; Tang, Y.S.; Dragosits, U.; Kluizenaar, Y.de; Sutton, M.A.

    2005-01-01

    Atmospheric budgets of reduced nitrogen for the major political regions of the British Isles are investigated with a multi-layer atmospheric transport model. The model is validated against measurements of NH3 concentration and is developed to provide atmospheric budgets for defined subdomains of the

  16. Biomass burial and storage to reduce atmospheric CO2

    Science.gov (United States)

    Zeng, N.

    2012-04-01

    To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a theoretical carbon sequestration potential for wood burial is 10 ± 5 GtC/y, but probably 1-3 GtC/y can be realized in practice. Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other environmental concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from forest industry, the cost for wood burial is estimated to be 14/tCO2 (50/tC), lower than the typical cost for power plant CO2 capture with geological storage. The low cost for carbon sequestration with wood burial is possible because the technique uses the natural process of photosynthesis to remove carbon from the atmosphere. The technique is low tech, distributed, safe, and can be stopped at any time, thus an attractive option for large-scale implementation in a world-wide carbon market.

  17. Strongly reduced band gap in a correlated insulator in close proximity to a metal

    NARCIS (Netherlands)

    Hesper, R.; Tjeng, L.H; Sawatzky, G.A

    1997-01-01

    Using a combination of photoelectron and inverse photoelectron spectroscopy, we show that the band gap in a monolayer of C-60 on a Ag surface is strongly reduced from the solid C-60 surface value. We argue that this is a result of the reduction of the on-site molecular Coulomb interaction due to the

  18. Exploiting selective excitation of strongly coupled modes to reduce DMGD in multi-mode transmission systems

    NARCIS (Netherlands)

    van Weerdenburg, J.J.A.; Antonio-Lopez, J.E.; Alvarado-Zacarias, J.; Molin, D.; Bigot-Astruc, M.; van Uden, R.; de Waardt, H.; Koonen, A.M.J.; Amezcua-Correa, R.; Sillard, P.; Okonkwo, C.M.

    2016-01-01

    By exploiting strong coupling in higher-order modes, we experimentally demonstrate reduced differential mode group delay by a factor of 3. Comparing LP02+LP21 with respect to LP01+LP11 3-mode transmission, a 27% reduction in equalizer length is shown after 53.4km MMF transmission.

  19. Exceptionally strong sorption of infochemicals to activated carbon reduces their bioavailability to fish

    NARCIS (Netherlands)

    Jonker, Michiel T O; van Mourik, Louise

    2014-01-01

    The addition of activated carbon (AC) to sediments is a relatively new approach to remediate contaminated sites. Activated carbon strongly sorbs hydrophobic organic contaminants, thereby reducing their bioavailability and uptake in organisms. Because of its high sorption capacity, AC might, however,

  20. Prejudice and Racism, Year 2008--Still Going Strong: Research on Reducing Prejudice with Recommended Methodological Advances

    Science.gov (United States)

    Utsey, Shawn O.; Ponterotto, Joseph G.; Porter, Jerlym S.

    2008-01-01

    This article addresses the origins, mechanisms, and expressions of prejudice. A selective review of research finds strong support for the validity of G. W. Allport's (1954) contact hypothesis conditions in reducing prejudice. Methodological advances in the study of prejudice are reviewed, and implications of research findings for counselors are…

  1. Large methane releases lead to strong aerosol forcing and reduced cloudiness

    DEFF Research Database (Denmark)

    Kurten, T.; Zhou, L.; Makkonen, R.

    2011-01-01

    forcing that is comparable in magnitude to the long-wave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O-3 and CH4-OHaerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously......The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller...... contributions from the associated carbon dioxide or ozone increases. Here, we study the effect of strongly elevated methane (CH4) levels on oxidant and aerosol particle concentrations using a combination of chemistry-transport and general circulation models. A 10-fold increase in methane concentrations...

  2. Large methane releases lead to strong aerosol forcing and reduced cloudiness

    Directory of Open Access Journals (Sweden)

    T. Kurtén

    2011-07-01

    Full Text Available The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller contributions from the associated carbon dioxide or ozone increases. Here, we study the effect of strongly elevated methane (CH4 levels on oxidant and aerosol particle concentrations using a combination of chemistry-transport and general circulation models. A 10-fold increase in methane concentrations is predicted to significantly decrease hydroxyl radical (OH concentrations, while moderately increasing ozone (O3. These changes lead to a 70 % increase in the atmospheric lifetime of methane, and an 18 % decrease in global mean cloud droplet number concentrations (CDNC. The CDNC change causes a radiative forcing that is comparable in magnitude to the longwave radiative forcing ("enhanced greenhouse effect" of the added methane. Together, the indirect CH4-O3 and CH4-OH-aerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously large temperature changes associated with historic methane releases.

  3. Earth-Atmospheric Coupling Prior to Strong Earthquakes Analyzed by IR Remote Sensing Data

    Science.gov (United States)

    Freund, F.; Ouzounov, D.

    2001-12-01

    Earth-atmosphere interactions during major earthquakes (M>5) are the subject of this study. A mechanism has recently been proposed to account for the appearance of hole-type electronic charge carriers in rocks subjected to transient stress [Freund, 2000]. If such charge carriers are activated in the crust prior to large earthquakes, the predictable consequences are: injection of currents into the rocks, low frequency electromagnetic emission, changes in ground potentials, corona discharges with attendant light emission from high points at the surface of the Earth, and possibly an enhanced emission in the 8-12 μ m region similar to the thermal emission observed during laboratory rock deformation experiments [Geng et al., 1999]. Using data from MODIS (Moderate Resolution Imaging Spectroradiometer) and ASTER (Advanced Spaceborne Thermal Emission & Reflection radiometer) onboard NASA's TERRA satellite launched in Dec. 1999 we have begun analyzing vertical atmospheric profiles, land surface and kinetic temperatures. We looked for correlations between atmospheric dynamics and solid Earth processes prior to the Jan. 13, 2001 earthquake in El Salvador (M=7.6) and the Jan. 26, 2001 Gujarat earth-quake in India (M=7.7). With MODIS covering the entire Earth every 1-2 days in 36 wavelength bands (20 visible and 16 infrared) at different spatial resolutions (250 m, 500 m, and 1 km) we find evidence for a thermal anomaly pattern related to the pre-seismic activity. We also find evidence for changes in the aerosol content and atmospheric instability parameters, possibly due to changes in the ground potential that cause ion emission and lead to the formation of a thin near-ground aerosol layer. We analyze the aerosol content, atmospheric pressure, moisture profile and lifted index.

  4. Reduced Lung Cancer Mortality With Lower Atmospheric Pressure.

    Science.gov (United States)

    Merrill, Ray M; Frutos, Aaron

    2018-01-01

    Research has shown that higher altitude is associated with lower risk of lung cancer and improved survival among patients. The current study assessed the influence of county-level atmospheric pressure (a measure reflecting both altitude and temperature) on age-adjusted lung cancer mortality rates in the contiguous United States, with 2 forms of spatial regression. Ordinary least squares regression and geographically weighted regression models were used to evaluate the impact of climate and other selected variables on lung cancer mortality, based on 2974 counties. Atmospheric pressure was significantly positively associated with lung cancer mortality, after controlling for sunlight, precipitation, PM2.5 (µg/m 3 ), current smoker, and other selected variables. Positive county-level β coefficient estimates ( P atmospheric pressure were observed throughout the United States, higher in the eastern half of the country. The spatial regression models showed that atmospheric pressure is positively associated with age-adjusted lung cancer mortality rates, after controlling for other selected variables.

  5. Glacial ocean circulation and stratification explained by reduced atmospheric temperature

    OpenAIRE

    Jansen, Malte F.

    2016-01-01

    To understand climatic swings between glacial and interglacial climates we need to explain the observed fluctuations in atmospheric carbon dioxide (CO2), which in turn are most likely driven by changes in the deep ocean circulation. This study presents a model for differences in the deep ocean circulation between glacial and interglacial climates consistent with both our physical understanding and various proxy observations. The results suggest that observed changes in ocean circulation and s...

  6. Experimental Observation of Strongly Bound Dimers of Sulfuric Acid: Application to Nucleation in the Atmosphere

    DEFF Research Database (Denmark)

    Petaja, Tuukka; Sipila, Mikko; Paasonen, Pauli

    2011-01-01

    rate was clearly higher than the measured new particle formation rate at similar to 1.5 nmsuggesting that the rate limiting step for the nucleation takes place after the dimerization step. The quantum chemical calculations suggested that even in the ultraclean conditions there exist (a) stabilizing...... compound(s) with (a) concentration(s) high enough to prevent the dimer evaporation. Such a stabilizing compound should be abundant enough in any natural environment and would therefore not limit the formation of sulfuric acid dimers in the atmosphere....

  7. An Accurate Computational Tool for Performance Estimation of FSO Communication Links over Weak to Strong Atmospheric Turbulent Channels

    Directory of Open Access Journals (Sweden)

    Theodore D. Katsilieris

    2017-03-01

    Full Text Available The terrestrial optical wireless communication links have attracted significant research and commercial worldwide interest over the last few years due to the fact that they offer very high and secure data rate transmission with relatively low installation and operational costs, and without need of licensing. However, since the propagation path of the information signal, i.e., the laser beam, is the atmosphere, their effectivity affects the atmospheric conditions strongly in the specific area. Thus, system performance depends significantly on the rain, the fog, the hail, the atmospheric turbulence, etc. Due to the influence of these effects, it is necessary to study, theoretically and numerically, very carefully before the installation of such a communication system. In this work, we present exactly and accurately approximate mathematical expressions for the estimation of the average capacity and the outage probability performance metrics, as functions of the link’s parameters, the transmitted power, the attenuation due to the fog, the ambient noise and the atmospheric turbulence phenomenon. The latter causes the scintillation effect, which results in random and fast fluctuations of the irradiance at the receiver’s end. These fluctuations can be studied accurately with statistical methods. Thus, in this work, we use either the lognormal or the gamma–gamma distribution for weak or moderate to strong turbulence conditions, respectively. Moreover, using the derived mathematical expressions, we design, accomplish and present a computational tool for the estimation of these systems’ performances, while also taking into account the parameter of the link and the atmospheric conditions. Furthermore, in order to increase the accuracy of the presented tool, for the cases where the obtained analytical mathematical expressions are complex, the performance results are verified with the numerical estimation of the appropriate integrals. Finally, using

  8. REDUCING AMMONIA CONCENTRATIONS IN ATMOSPHERE AFTER ITS UNPLANNED RELEASE

    Directory of Open Access Journals (Sweden)

    L. V. Amelina

    2017-08-01

    Full Text Available Purpose. The aim of this work is development of numerical model, which allows to calculate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia emission at the territory of ammonia pump station. The numerical model should allow fast calculating, taking into account the meteorological parameters and buildings situated near the source of toxic chemical emission and equipment for neutralizer supply. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. To simulate the chemical interaction between ammonia and neutralizer the stoichiometry equation is used. Equation of potential flow is used to compute flow pattern among buildings. To solve the equation for potential flow the Samarskii implicit difference scheme is used. The implicit change-triangle difference scheme is used to solve equation of mass transfer. While for the numerical integration the authors use the rectangular difference grid. Method of porosity technique («markers method» is applied to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of ammonia and neutralizer in the atmosphere, as well as the influence of buildings on admixture dispersion. On the basis of the developed numerical models the authors carried out a computational experiment to estimate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows calculating the flow pattern among buildings and estimating the efficiency of neutralizer supply for reduction of air pollution in the case unplanned ammonia release. Practical value. Model allows performing fast

  9. Pressurized Martian-Like Pure CO2 Atmosphere Supports Strong Growth of Cyanobacteria, and Causes Significant Changes in their Metabolism

    Science.gov (United States)

    Murukesan, Gayathri; Leino, Hannu; Mäenpää, Pirkko; Ståhle, Kurt; Raksajit, Wuttinun; Lehto, Harry J.; Allahverdiyeva-Rinne, Yagut; Lehto, Kirsi

    2016-03-01

    Surviving of crews during future missions to Mars will depend on reliable and adequate supplies of essential life support materials, i.e. oxygen, food, clean water, and fuel. The most economical and sustainable (and in long term, the only viable) way to provide these supplies on Martian bases is via bio-regenerative systems, by using local resources to drive oxygenic photosynthesis. Selected cyanobacteria, grown in adequately protective containment could serve as pioneer species to produce life sustaining substrates for higher organisms. The very high (95.3 %) CO2 content in Martian atmosphere would provide an abundant carbon source for photo-assimilation, but nitrogen would be a strongly limiting substrate for bio-assimilation in this environment, and would need to be supplemented by nitrogen fertilizing. The very high supply of carbon, with rate-limiting supply of nitrogen strongly affects the growth and the metabolic pathways of the photosynthetic organisms. Here we show that modified, Martian-like atmospheric composition (nearly 100 % CO2) under various low pressure conditions (starting from 50 mbar to maintain liquid water, up to 200 mbars) supports strong cellular growth. Under high CO2 / low N2 ratio the filamentous cyanobacteria produce significant amount of H2 during light due to differentiation of high amount of heterocysts.

  10. Non-ammonium reduced nitrogen species in atmospheric aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Dod, R.L.; Gundel, L.A.; Benner, W.H.; Novakov, T.

    1983-08-01

    The traditional belief that ambient aerosol particles contain nitrogen predominantly in the form of inorganic ionic species such as NH/sub 4//sup +/ and NO/sub 3//sup -/ was challenged about 10 years ago by results from x-ray photoelectron spectroscopic analysis (ESCA) of California aerosol particles. A significant fraction (approx. 50%) of the reduced nitrogen was observed to have an oxidation state more reduced than ammonium, characteristic of organic nitrogen species. We have used a recently developed thermal evolved gas analysis method (NO/sub x/) in conjunction with ESCA to confirm the existence of these species in aerosol particles collected in both the United States and Europe. The agreement of EGA and ESCA analyses indicates that these species are found not only on the surface but also throughout the particles. 9 references, 6 figures.

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

    Science.gov (United States)

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

    2013-12-01

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

  12. Methods for Creation and Detection of Ultra-Strong Artificial Ionization in the Upper Atmosphere (Invited)

    Science.gov (United States)

    Bernhardt, P. A.; Siefring, C. L.; Briczinski, S. J.; Kendall, E. A.; Watkins, B. J.; Bristow, W. A.; Michell, R.

    2013-12-01

    The High Frequency Active Auroral Research Program (HAARP) transmitter in Alaska has been used to produce localized regions of artificial ionization at altitudes between 150 and 250 km. High power radio waves tuned near harmonics of the electron gyro frequency were discovered by Todd Pederson of the Air Force Research Laboratory to produce ionosonde traces that looked like artificial ionization layers below the natural F-region. The initial regions of artificial ionization (AI) were not stable but had moved down in altitude over a period of 15 minutes. Recently, artificial ionization has been produced by the 2nd, 3rd, 4th and 6th harmonics transmissions by the HAARP. In march 2013, the artificial ionization clouds were sustained for more the 5 hours using HAARP tuned to the 4 fce at the full power of 3.6 Mega-Watts with a twisted-beam antenna pattern. Frequency selection with narrow-band sweeps and antenna pattern shaping has been employed for optimal generation of AI. Recent research at HAARP has produced the longest lived and denser artificial ionization clouds using HF transmissions at the harmonics of the electron cyclotron frequency and ring-shaped radio beams tailored to prevent the descent of the clouds. Detection of artificial ionization employs (1) ionosonde echoes, (2) coherent backscatter from the Kodiak SuperDARN radar, (3) enhanced ion and plasma line echoes from the HAARP MUIR radar at 400 MHz, (4) high resolution optical image from ground sites, and (5) unique stimulated electromagnetic emissions, and (6) strong UHF and L-Band scintillation induced into trans-ionospheric signals from satellite radio beacons. Future HAARP experiments will determine the uses of long-sustained AI for enhanced HF communications.

  13. Bi-decadal variability excited in the coupled ocean-atmosphere system by strong tropical volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Zanchettin, D.; Lorenz, S.; Lohmann, K.; Jungclaus, J.H. [Max Planck Institute for Meteorology, Ocean in the Earth System Department, Hamburg (Germany); Timmreck, C. [Max Planck Institute for Meteorology, Atmosphere in the Earth System Department, Hamburg (Germany); Graf, H.-F. [University of Cambridge, Centre for Atmospheric Science, Cambridge (United Kingdom); Rubino, A. [Ca' Foscari University, Department of Environmental Sciences, Venice (Italy); Krueger, K. [Leibniz-Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany)

    2012-07-15

    Decadal and bi-decadal climate responses to tropical strong volcanic eruptions (SVEs) are inspected in an ensemble simulation covering the last millennium based on the Max Planck Institute - Earth system model. An unprecedentedly large collection of pre-industrial SVEs (up to 45) producing a peak annual-average top-of-atmosphere radiative perturbation larger than -1.5 Wm{sup -2} is investigated by composite analysis. Post-eruption oceanic and atmospheric anomalies coherently describe a fluctuation in the coupled ocean-atmosphere system with an average length of 20-25 years. The study provides a new physically consistent theoretical framework to interpret decadal Northern Hemisphere (NH) regional winter climates variability during the last millennium. The fluctuation particularly involves interactions between the Atlantic meridional overturning circulation and the North Atlantic gyre circulation closely linked to the state of the winter North Atlantic Oscillation. It is characterized by major distinctive details. Among them, the most prominent are: (a) a strong signal amplification in the Arctic region which allows for a sustained strengthened teleconnection between the North Pacific and the North Atlantic during the first post-eruption decade and which entails important implications from oceanic heat transport and from post-eruption sea ice dynamics, and (b) an anomalous surface winter warming emerging over the Scandinavian/Western Russian region around 10-12 years after a major eruption. The simulated long-term climate response to SVEs depends, to some extent, on background conditions. Consequently, ensemble simulations spanning different phases of background multidecadal and longer climate variability are necessary to constrain the range of possible post-eruption decadal evolution of NH regional winter climates. (orig.)

  14. Tritium concentration reducing method in atmosphere in nuclear reactor containment facility

    International Nuclear Information System (INIS)

    Hirasawa, Yoshiya; Kigoshi, Yasutane; Yonenaga, Haruo.

    1992-01-01

    A portion of water content in an atmosphere is condensed by a condensation/evaporation device disposed in a nuclear reactor containment building and then a portion of the condensed water is evaporated in the atmosphere. A portion of hydrogen nuclides constituting the evaporated water content is subjected to isotopic exchange with tritium nuclides in the atmosphere. A portion of water content in the atmosphere applied with the isotopic exchange is condensed in the condensation/evaporation device. That is, the hydrogen nuclides in steams are applied with isotopic exchange with tritium nuclides, and steams incorporating tritium nuclides are condensed again in the condensation/evaporation device, to transfer the tritium nuclides in the atmosphere to condensed water. The condensed water is recovered without releasing the tritium nuclides to the outside of the reactor containment building, thereby enabling to reduce the tritium concentration in the atmosphere. (N.H.)

  15. Performance analysis of relay-assisted all-optical FSO networks over strong atmospheric turbulence channels with pointing errors

    KAUST Repository

    Yang, Liang

    2014-12-01

    In this study, we consider a relay-assisted free-space optical communication scheme over strong atmospheric turbulence channels with misalignment-induced pointing errors. The links from the source to the destination are assumed to be all-optical links. Assuming a variable gain relay with amplify-and-forward protocol, the electrical signal at the source is forwarded to the destination with the help of this relay through all-optical links. More specifically, we first present a cumulative density function (CDF) analysis for the end-to-end signal-to-noise ratio. Based on this CDF, the outage probability, bit-error rate, and average capacity of our proposed system are derived. Results show that the system diversity order is related to the minimum value of the channel parameters.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  17. Large methane releases lead to strong aerosol forcing and reduced cloudiness

    DEFF Research Database (Denmark)

    Kurten, T.; Zhou, L.; Makkonen, R.

    2011-01-01

    The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller...... is predicted to significantly decrease hydroxyl radical (OH) concentrations, while moderately increasing ozone (O-3). These changes lead to a 70% increase in the atmospheric lifetime of methane, and an 18% decrease in global mean cloud droplet number concentrations (CDNC). The CDNC change causes a radiative...... forcing that is comparable in magnitude to the long-wave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O-3 and CH4-OHaerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously...

  18. Reduced calcification of marine plankton in response to increased atmospheric CO2.

    Science.gov (United States)

    Riebesell, U; Zondervan, I; Rost, B; Tortell, P D; Zeebe, R E; Morel, F M

    2000-09-21

    The formation of calcareous skeletons by marine planktonic organisms and their subsequent sinking to depth generates a continuous rain of calcium carbonate to the deep ocean and underlying sediments. This is important in regulating marine carbon cycling and ocean-atmosphere CO2 exchange. The present rise in atmospheric CO2 levels causes significant changes in surface ocean pH and carbonate chemistry. Such changes have been shown to slow down calcification in corals and coralline macroalgae, but the majority of marine calcification occurs in planktonic organisms. Here we report reduced calcite production at increased CO2 concentrations in monospecific cultures of two dominant marine calcifying phytoplankton species, the coccolithophorids Emiliania huxleyi and Gephyrocapsa oceanica. This was accompanied by an increased proportion of malformed coccoliths and incomplete coccospheres. Diminished calcification led to a reduction in the ratio of calcite precipitation to organic matter production. Similar results were obtained in incubations of natural plankton assemblages from the north Pacific ocean when exposed to experimentally elevated CO2 levels. We suggest that the progressive increase in atmospheric CO2 concentrations may therefore slow down the production of calcium carbonate in the surface ocean. As the process of calcification releases CO2 to the atmosphere, the response observed here could potentially act as a negative feedback on atmospheric CO2 levels.

  19. Dopamine D(1) receptor deletion strongly reduces neurotoxic effects of methamphetamine.

    Science.gov (United States)

    Ares-Santos, S; Granado, N; Oliva, I; O'Shea, E; Martin, E D; Colado, M I; Moratalla, R

    2012-02-01

    Methamphetamine (METH) is a potent, highly addictive psychostimulant consumed worldwide. In humans and experimental animals, repeated exposure to this drug induces persistent neurodegenerative changes. Damage occurs primarily to dopaminergic neurons, accompanied by gliosis. The toxic effects of METH involve excessive dopamine (DA) release, thus DA receptors are highly likely to play a role in this process. To define the role of D(1) receptors in the neurotoxic effects of METH we used D(1) receptor knock-out mice (D(1)R(-/-)) and their WT littermates. Inactivation of D(1)R prevented METH-induced dopamine fibre loss and hyperthermia, and increases in gliosis and pro-inflammatory molecules such as iNOS in the striatum. In addition, D(1)R inactivation prevented METH-induced loss of dopaminergic neurons in the substantia nigra. To explore the relationship between hyperthermia and neurotoxicity, METH was given at high ambient temperature (29 °C). In this condition, D(1)R(-/-) mice developed hyperthermia following drug delivery and the neuroprotection provided by D(1)R inactivation at 23 °C was no longer observed. However, reserpine, which empties vesicular dopamine stores, blocked hyperthermia and strongly potentiated dopamine toxicity in D(1)R(-/-) mice, suggesting that the protection afforded by D(1)R inactivation is due to both hypothermia and higher stored vesicular dopamine. Moreover, electrical stimulation evoked higher DA overflow in D(1)R(-/-) mice as demonstrated by fast scan cyclic voltammetry despite their lower basal DA content, suggesting higher vesicular DA content in D(1)R(-/-) than in WT mice. Altogether, these results indicate that the D(1)R plays a significant role in METH-induced neurotoxicity by mediating drug-induced hyperthermia and increasing the releasable cytosolic DA pool. Copyright © 2011. Published by Elsevier Inc.

  20. Strongly reduced band gap in NiMn2O4 due to cation exchange

    International Nuclear Information System (INIS)

    Huang, Jhih-Rong; Hsu, Han; Cheng, Ching

    2014-01-01

    NiMn 2 O 4 is extensively used as a basis material for temperature sensors due to its negative temperature coefficient of resistance (NTCR), which is commonly attributed to the hopping mechanism involving coexisting octahedral-site Mn 4+ and Mn 3+ . Using density-functional theory + Hubbard U calculations, we identify a ferrimagnetic inverse spinel phase as the collinear ground state of NiMn 2 O 4 . By a 12.5% cation exchange, a mixed phase with slightly higher energy can be constructed, accompanied by the formation of an impurity-like band in the original 1 eV band gap. This impurity-like band reduces the gap to 0.35 eV, suggesting a possible source of NTCR. - Highlights: • Density functional based calculations were used to study collinear phase of NiMn 2 O 4 . • The ground-state structure is a ferrimagnetic inverse spinel phase. • The tetrahedral and octahedral Mn cations have ferromagnetic interactions. • A 12.5% cation exchange introduces an impurity-like band in the original 1 eV gap. • The 0.35 eV gap suggests a source of negative temperature coefficient of resistance

  1. A New Sugarcane Cystatin Strongly Binds to Dental Enamel and Reduces Erosion.

    Science.gov (United States)

    Santiago, A C; Khan, Z N; Miguel, M C; Gironda, C C; Soares-Costa, A; Pelá, V T; Leite, A L; Edwardson, J M; Buzalaf, M A R; Henrique-Silva, F

    2017-08-01

    Cystatin B was recently identified as an acid-resistant protein in acquired enamel pellicle; it could therefore be included in oral products to protect against caries and erosion. However, human recombinant cystatin is very expensive, and alternatives to its use are necessary. Phytocystatins are reversible inhibitors of cysteine peptidases that are found naturally in plants. In plants, they have several biological and physiological functions, such as the regulation of endogenous processes, defense against pathogens, and response to abiotic stress. Previous studies performed by our research group have reported high inhibitory activity and potential agricultural and medical applications of several sugarcane cystatins, including CaneCPI-1, CaneCPI-2, CaneCPI-3, and CaneCPI-4. In the present study, we report the characterization of a novel sugarcane cystatin, named CaneCPI-5. This cystatin was efficiently expressed in Escherichia coli, and inhibitory assays demonstrated that it was a potent inhibitor of human cathepsins B, K, and L ( K i = 6.87, 0.49, and 0.34 nM, respectively). The ability of CaneCPI-5 to bind to dental enamel was evaluated using atomic force microscopy. Its capacity to protect against initial enamel erosion was also tested in vitro via changes in surface hardness. CaneCPI-5 showed a very large force of interaction with enamel (e.g., compared with mucin and casein) and significantly reduced initial enamel erosion. These results suggest that the inclusion of CaneCPIs in dental products might confer protection against enamel erosion.

  2. The role of catchment vegetation in reducing atmospheric inputs of pollutant aerosols in Ganga river.

    Science.gov (United States)

    Shubhashish, Kumar; Pandey, Richa; Pandey, Jitendra

    2012-08-01

    The role of woody perennials in the Ganga river basin in modifying the run-off quality as influenced by atmospheric deposition of pollutant aerosols was investigated. The concentration of seven nutrients and eight metals were measured in atmospheric deposits as well as in run-off water under the influence of five woody perennials. Nutrient retention was recorded maximum for Bougainvillea spectabilis ranged from 4.30 % to 33.70 %. Metal retention was recorded highest for Ficus benghalensis ranged from 5.15 % to 36.98 %. Although some species showed nutrient enrichment, all the species considered in the study invariably contribute to reduce nutrients and metal concentration in run-off water. Reduction in run off was recorded maximum for B. spectabilis (nutrient 6.48 %-40.66 %; metal 7.86 %-22.85 %) and minimum for Ficus religiosa (nutrient 1.68 %-27.19 %; metal 6.55 %-31.55 %). The study forms the first report on the use of woody perennials in reducing input of atmospheric pollutants to Ganga river and has relevance in formulating strategies for river basin management.

  3. Preparation of carbon nanotubes by DC arc discharge process under reduced pressure in an air atmosphere

    International Nuclear Information System (INIS)

    Kim, Hyeon Hwan; Kim, Hyeong Joon

    2006-01-01

    Carbon nanotubes (CNTs) were grown using a DC arc discharge process in an air atmosphere and relevant process parameters were investigated. Without using an inert gas, multi walled carbon nanotubes could be synthesized in the deposit area of the cathode even in an air atmosphere, but single walled carbon nanotubes were not detected in the soot area despite using the same process conditions as in the inert gas. The air pressure for the highest yield of multi walled CNTs was 300 Torr. In addition, the quantity of amorphous carbon and other nanoparticles in the process chamber was remarkably reduced by this technique, showing that an efficient, feasible method of large scale CNT fabrication could be achieved by the arc discharge process

  4. Osteoclast formation is strongly reduced both in vivo and in vitro in the absence of CD47/SIRPα-interaction

    International Nuclear Information System (INIS)

    Lundberg, Pernilla; Koskinen, Cecilia; Baldock, Paul A.; Loethgren, Hanna; Stenberg, Asa; Lerner, Ulf H.; Oldenborg, Per-Arne

    2007-01-01

    Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPα) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPα-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPα strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP) + osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47 -/- mice were strongly reduced, and bones of CD47 -/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPα interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47 -/- mice

  5. CONCENTRATION OF HARMFUL SUBSTANCES REDUCING IN SURFACE LAYER OF ATMOSPHERE AT RHEOSTAT LOCOMOTIVE TESTS

    Directory of Open Access Journals (Sweden)

    E. A. Bondar

    2010-06-01

    Full Text Available It is shown that at present an acceptable way of reducing the concentration of harmful substances in the surface layer of the atmosphere at rheostat tests of locomotives is their dispersion in a large volume of air. Channels, installed above an exhaust pipe of diesel locomotive with a break at the gas flow, work as ejectors. We have solved jointly the equation of aerodynamic characteristics of the ejector device and the equation of diffusion of gases; as a result the calculated dependence for determining the necessary height of ejector device has been obtained.

  6. Synthesis and characterization of some reduced ternary and quaternary molybdenum oxide phases with strong metal-metal bonds

    International Nuclear Information System (INIS)

    Lii, K.H.

    1985-10-01

    In the course of our research on reduced ternary and quaternary molybdenum oxides, very interesting compounds with strong metal-metal bonds were discovered. Among these solid-state materials are found discrete cluster arrays and structures with extended metal-metal bonding. Further study in this system has revealed that many new structures exist in this new realm. The synthesis, structures, bonding, and properties of these new oxides, which are briefly summarized in tabular form, are presented in this thesis. 144 refs., 63 figs., 79 tabs

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

    Science.gov (United States)

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

    2018-01-01

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

  8. Hierarchically porous, ultra-strong reduced graphene oxide-cellulose nanocrystal sponges for exceptional adsorption of water contaminants

    DEFF Research Database (Denmark)

    Yousefi, Nariman; Wong, Kerwin K.W.; Hosseinidoust, Zeinab

    2018-01-01

    Self-assembly of graphene oxide (GO) nanosheets into porous 3D sponges is a promising approach to exploit their capacity to adsorb contaminants while facilitating the recovery of the nanosheets from treated water. Yet, forming mechanically robust sponges with suitable adsorption properties presents...... a significant challenge. Ultra-strong and highly porous 3D sponges are formed using GO, vitamin C (VC), and cellulose nanocrystals (CNCs) - natural nanorods isolated from wood pulp. CNCs provide a robust scaffold for the partially reduced GO (rGO) nanosheets resulting in an exceptionally stiff nanohybrid....... The concentration of VC as a reducing agent plays a critical role in tailoring the pore architecture of the sponges. By using excess amounts of VC, a unique hierarchical pore structure is achieved, where VC grains act as soft templates for forming millimeter-sized pores, the walls of which are also porous...

  9. Phase separation of cesium from lead borosilicate glass by heat treatment under a reducing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

    2016-11-05

    Highlights: • Cesium was phase separated from lead borosilicate glass under a reductive atmosphere. • The phase separation occurred on the glass surface that was in contact with the gas. • The leachability of cesium was enhanced by the phase separation. • The degree of such enhancement varied depending on the heat treatment conditions. - Abstract: A phase-separation technique for removing sodium from glass using a heat-treatment method under a reducing atmosphere was previously developed for sodium recovery from waste glass. In this study, this technique was applied to cesium-containing lead borosilicate glass to concentrate the cesium in phase-separated sodium-rich materials for efficient cesium extraction. The theoretical phase-separation temperature of the sodium-rich phase was simulated by thermodynamic equilibrium calculations and was predicted to occur below 700 °C for lead borosilicate glass. Experimentally, a simulated lead borosilicate glass was melted at 1000 °C and subsequently annealed below 700 °C under a CO-containing reducing atmosphere. The phase separation of cesium was found to occur with sodium enrichment on the glass surface that was in contact with the gas phase, promoting cesium extraction from the treated glass using water. The cesium extraction efficiency was affected by the surface area of the treated glass that was in contact with water, and under the examined conditions, the cesium extraction efficiency was up to 66%. Phase separation using reductive heat treatment, combined with a water leaching technique, is suggested to be effective for extracting cesium incorporated in borosilicate glass waste.

  10. Hall effect in a strong magnetic field: Direct comparisons of compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic equations

    International Nuclear Information System (INIS)

    Martin, L. N.; Dmitruk, P.; Gomez, D. O.

    2010-01-01

    In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.

  11. Permafrost thaw strongly reduces allowable CO2 emissions for 1.5°C and 2°C

    Science.gov (United States)

    Kechiar, M.; Gasser, T.; Kleinen, T.; Ciais, P.; Huang, Y.; Burke, E.; Obersteiner, M.

    2017-12-01

    We quantify how the inclusion of carbon emission from permafrost thaw impacts the budgets of allowable anthropogenic CO2 emissions. We use the compact Earth system model OSCAR v2.2 which we expand with a permafrost module calibrated to emulate the behavior of the complex models JSBACH, ORCHIDEE and JULES. When using the "exceedance" method and with permafrost thaw turned off, we find budgets very close to the CMIP5 models' estimates reported by IPCC. With permafrost thaw turned on, the total budgets are reduced by 3-4%. This corresponds to a 33-45% reduction of the remaining budget for 1.5°C, and a 9-13% reduction for 2°C. When using the "avoidance" method, however, permafrost thaw reduces the total budget by 3-7%, which corresponds to reductions by 33-56% and 56-79% of the remaining budget for 1.5°C and 2°C, respectively. The avoidance method relies on many scenarios that actually peak below the target whereas the exceedance method overlooks the carbon emitted by thawed permafrost after the temperature target is reached, which explains the difference. If we use only the subset of scenarios in which there is no net negative emissions, the permafrost-induced reduction in total budgets rises to 6-15%. Permafrost thaw therefore makes the emission budgets strongly path-dependent. We also estimate budgets of needed carbon capture in scenarios overshooting the temperature targets. Permafrost thaw strongly increases these capture budgets: in the case of a 1.5°C target overshot by 0.5°C, which is in line with the Paris agreement, about 30% more carbon must be captured. Our conclusions are threefold. First, inclusion of permafrost thaw systematically reduces the emission budgets, and very strongly so if the temperature target is overshot. Second, the exceedance method, that is the only one that complex models can follow, only partially accounts for the effect of slow non-linear processes such as permafrost thaw, leading to overestimated budgets. Third, the newfound

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  13. Effect of Oxygen-Reducing Atmospheres on the Safety of Packaged Shelled Brazil Nuts during Storage

    Directory of Open Access Journals (Sweden)

    Vildes Maria Scussel

    2011-01-01

    Full Text Available This work reports the application of oxygen-(O2- reducing atmosphere methods on stored shelled Brazil nut (Bertholletia excelsa H.B.K. packs aiming to evaluate the degree of aflatoxin degradation, nuts lipid oxidative stability, fungi control, and hygienic conditions improvement. The methods applied were (a ozone: O3, (b carbon dioxide: CO2, and (c O2 absorber pads with and without vacuum. From all modified atmospheres evaluated, the best performance was obtained with O3, either with or without vacuum. It was the only nut treatment that was able to degrade aflatoxins. None of the spiked (AFLs: 15 μg·kg−1 nut samples O3- treated had aflatoxins detected up to the LC-MS/MS method LOQ (0.36 μg·kg−1 for total AFLs, thus producing safer nuts. Also it kept the fatty acid oxidation indicator—malondialdehyde stable and improved the sensory attributes for consumer acceptance. In addition, the destruction of fungi and yeast was observed since the O3 application (from 1.8×104 cfu/g to NG = no growth. All other treatments stabilized and/or inhibited microorganisms' growth only. By adding CO2 gas also played an important role in the nut quality. Regarding cost, gaseous O3 showed to be of low cost for application in the nut packs.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  15. A Reduced-order NLTE Kinetic Model for Radiating Plasmas of Outer Envelopes of Stellar Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Munafò, Alessandro [Aerospace Engineering Department, University of Illinois at Urbana-Champaign, 206A Talbot Lab., 104 S. Wright Street, Urbana, IL 61801 (United States); Mansour, Nagi N. [NASA Ames Research Center, Moffett Field, 94035 CA (United States); Panesi, Marco, E-mail: munafo@illinois.edu, E-mail: nagi.n.mansour@nasa.gov, E-mail: m.panesi@illinois.edu [Aerospace Engineering Department, University of Illinois at Urbana-Champaign, 306 Talbot Lab., 104 S. Wright Street, Urbana, IL 61801 (United States)

    2017-04-01

    The present work proposes a self-consistent reduced-order NLTE kinetic model for radiating plasmas found in the outer layers of stellar atmospheres. A detailed collisional-radiative kinetic mechanism is constructed by leveraging the most up-to-date set of ab initio and experimental data available in the literature. This constitutes the starting point for the derivation of a reduced-order model, obtained by lumping the bound energy states into groups. In order to determine the needed thermo-physical group properties, uniform and Maxwell–Boltzmann energy distributions are used to reconstruct the energy population of each group. Finally, the reduced set of governing equations for the material gas and the radiation field is obtained based on the moment method. Applications consider the steady flow across a shock wave in partially ionized hydrogen. The results clearly demonstrate that adopting a Maxwell–Boltzmann grouping allows, on the one hand, for a substantial reduction of the number of unknowns and, on the other, to maintain accuracy for both gas and radiation quantities. Also, it is observed that, when neglecting line radiation, the use of two groups already leads to a very accurate resolution of the photo-ionization precursor, internal relaxation, and radiative cooling regions. The inclusion of line radiation requires adopting just one additional group to account for optically thin losses in the α , β , and γ lines of the Balmer and Paschen series. This trend has been observed for a wide range of shock wave velocities.

  16. Methanol and ethanol vapor conversion in gas discharge with strongly non-uniform distribution of electric field on atmospheric pressure

    International Nuclear Information System (INIS)

    Golota, V.I.; Zavada, L.M.; Kotyukov, O.V.; Kudin, D.V.; Rodionov, S.V.; Pis'menetskoj, A.S.; Dotsenko, Yu.V.

    2010-01-01

    The barrierless gas discharge of negative polarity with strongly non-uniform distribution of electrical field in the methanol and ethanol vapour was studied. It is shown that level of methanol and ethanol conversion depended from power consumed by the discharge and exposition time for gas mixture in discharge zone. The condition for deep conversion of the methanol and ethanol vapours were determined. The water and carbon dioxide are the end products for the methanol and ethanol conversion. Formaldehyde and formic acid are the intermediates products in the conversion of methanol. And ethanol has a number of different compounds, including acetic acid, acetaldehyde, etc.

  17. Photoprotection, photosynthesis and growth of tropical tree seedlings under near-ambient and strongly reduced solar ultraviolet-B radiation.

    Science.gov (United States)

    Krause, G Heinrich; Jahns, Peter; Virgo, Aurelio; García, Milton; Aranda, Jorge; Wellmann, Eckard; Winter, Klaus

    2007-10-01

    Seedlings of two late-successional tropical rainforest tree species, Tetragastris panamensis (Engler) O. Kuntze and Calophyllum longifolium (Willd.), were field grown for 3-4 months at an open site near Panama City (9 degrees N), Panama, under plastic films that either transmitted or excluded most solar UV-B radiation. Experiments were designed to test whether leaves developing under bright sunlight with strongly reduced UV-B are capable of acclimating to near-ambient UV-B conditions. Leaves of T. panamensis that developed under near-ambient UV-B contained higher amounts of UV-absorbing substances than leaves of seedlings grown under reduced UV-B. Photosynthetic pigment composition, content of alpha-tocopherol, CO(2) assimilation, potential photosystem II (PSII) efficiency (evaluated by F(v)/F(m) ratios) and growth of T. panamensis and C. longifolium did not differ between seedlings developed under near-ambient and reduced solar UV-B. When seedlings were transferred from the reduced UV-B treatment to the near-ambient UV-B treatment, a pronounced inhibition of photosynthetic capacity was observed initially in both species. UV-B-mediated inhibition of photosynthetic capacity nearly fully recovered within 1 week of the transfer in C. longifolium, whereas in T. panamensis an about 35% reduced capacity of CO(2) uptake was maintained. A marked increase in UV-absorbing substances was observed in foliage of transferred T. panamensis seedlings. Both species exhibited enhanced mid-day photoinhibition of PSII immediately after being transferred from the reduced UV-B to the near-ambient UV-B treatment. This effect was fully reversible within 1d in T. panamensis and within a few days in C. longifolium. The data show that leaves of these tropical tree seedlings, when developing in full-spectrum sunlight, are effectively protected against high solar UV-B radiation. In contrast, leaves developing under conditions of low UV-B lacked sufficient UV protection. They experienced a

  18. Further analysis of scintillation index for a laser beam propagating through moderate-to-strong non-Kolmogorov turbulence based on generalized effective atmospheric spectral model

    Science.gov (United States)

    Ma, Jing; Fu, Yu-Long; Yu, Si-Yuan; Xie, Xiao-Long; Tan, Li-Ying

    2018-03-01

    A new expression of the scintillation index (SI) for a Gaussian-beam wave propagating through moderate-to-strong non-Kolmogorov turbulence is derived, using a generalized effective atmospheric spectrum and the extended Rytov approximation theory. Finite inner and outer scale parameters and high wave number “bump” are considered in the spectrum with a generalized spectral power law in the range of 3–4, instead of the fixed classical Kolmogorov power law of 11/3. The obtained SI expression is then used to analyze the effects of the spectral power law and the inner scale and outer scale on SI under various non-Kolmogorov fluctuation conditions. These results will be useful in future investigations of optical wave propagation through atmospheric turbulence.

  19. Effects of sintering atmosphere and temperature on structural and magnetic properties of Ni-Cu-Zn ferrite nano-particles: Magnetic enhancement by a reducing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gholizadeh, Ahmad, E-mail: gholizadeh@du.ac.ir; Jafari, Elahe, E-mail: ah_gh1359@yahoo.com

    2017-01-15

    In this work, effects of sintering atmosphere and temperature on structural and magnetic properties of Ni{sub 0.3}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} nanoparticles prepared by citrate precursor method have been studied. The structural characterization of the samples by X-ray powder diffraction and FT-IR spectroscopy is evidence for formation of a cubic structure with no presence of impurity phase. Calculated values of crystallite size and unit cell parameter show an increase with sintering temperature under different atmospheres. Variation of saturation magnetization with sintering temperature and atmosphere can be attributed to change of three factors: magnetic core size, inversion parameter and the change of Fe{sup 3+}-ion concentration due to the presence of Fe{sup 4+} and Fe{sup 2+} ions. The saturation magnetization gradually grows with sintering temperature due to increase of magnetic core size and a maximum 63 emu/g was achieved at 600 °C under carbon monoxide-ambient atmosphere. - Highlights: • Different sintering atmosphere and temperature cause substantial differences in Ni{sub 0.3}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} nanoparticles. • The saturation magnetization gradually grows. • A maximum 63 emu/g was achieved at 600 °C under a reducing atmosphere.

  20. Reducing biases on H0 measurements using strong lensing and galaxy dynamics: results from the EAGLE simulation

    Science.gov (United States)

    Tagore, Amitpal S.; Barnes, David J.; Jackson, Neal; Kay, Scott T.; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2018-03-01

    Cosmological parameter constraints from observations of time-delay lenses are becoming increasingly precise. However, there may be significant bias and scatter in these measurements due to, among other things, the so-called mass-sheet degeneracy. To estimate these uncertainties, we analyse strong lenses from the largest EAGLE hydrodynamical simulation. We apply a mass-sheet transformation to the radial density profiles of lenses, and by selecting lenses near isothermality, we find that the bias on H0 can be reduced to 5 per cent with an intrinsic scatter of 10 per cent, confirming previous results performed on a different simulation data set. We further investigate whether combining lensing observables with kinematic constraints helps to minimize this bias. We do not detect any significant dependence of the bias on lens model parameters or observational properties of the galaxy, but depending on the source-lens configuration, a bias may still exist. Cross lenses provide an accurate estimate of the Hubble constant, while fold (double) lenses tend to be biased low (high). With kinematic constraints, double lenses show bias and intrinsic scatter of 6 per cent and 10 per cent, respectively, while quad lenses show bias and intrinsic scatter of 0.5 per cent and 10 per cent, respectively. For lenses with a reduced χ2 > 1, a power-law dependence of the χ2 on the lens environment (number of nearby galaxies) is seen. Lastly, we model, in greater detail, the cases of two double lenses that are significantly biased. We are able to remove the bias, suggesting that the remaining biases could also be reduced by carefully taking into account additional sources of systematic uncertainty.

  1. Options for cost-effectively reducing atmospheric methane concentrations from anthropogenic biomass sources

    International Nuclear Information System (INIS)

    Roos, K.F.; Jacobs, C.; Orlic, M.

    1993-01-01

    Methane is a major greenhouse gas, second only to carbon dioxide in its contribution to future global warming. Methane concentrations have more than doubled over the last two centuries and continue to rise annually. These increases are largely correlated with increasing human populations. Methane emissions from human related activities currently account for about 70 percent of annual emissions. Of these human related emissions, biomass sources account for about 75 percent and non-biomass sources about 25 percent. Because methane has a shorter lifetime than other major greenhouse gases, efforts to reduce methane emissions may fairly quickly be translated into lower atmospheric concentrations of methane and lower levels of radiative forcing. This fairly quick response would have the benefit of slowing the rate of climate change and hence allow natural ecosystems more time to adapt. Importantly, methane may be cost-effectively reduced from a number of biomass and non-biomass sources in the United States and worldwide. Methane is a valuable fuel, not just a waste by-product, and often systems may be reconfigured to reap the fuel value of the methane and more than justify the necessary expenditures. Such options for reducing methane emission from biomass sources exist for landfills, livestock manures, and ruminant livestock, and have been implemented to varying degrees in countries around the world. However, there are a number of barriers that hinder the more widespread use of technologies, including institutional, financial, regulatory, informational, and other barriers. This paper describes an array of available options that may be cost-effectively implemented to reduce methane emissions from biomass sources. This paper also discusses a number of programs that have been developed in the United States and internationally to promote the implementation of these methane reduction options and overcome existing barriers

  2. Men without a sense of smell exhibit a strongly reduced number of sexual relationships, women exhibit reduced partnership security - a reanalysis of previously published data.

    Science.gov (United States)

    Croy, Ilona; Bojanowski, Viola; Hummel, Thomas

    2013-02-01

    Olfactory function influences social behavior. For instance, olfaction seems to play a key role in mate choice and helps detecting emotions in other people. In a previous study, we showed that people who were born without a sense of smell exhibit enhanced social insecurity. Based on the comments to this article we decided to have a closer look to whether the absence of the sense of smell affects men and women differently. Under this focus questionnaire data of 32 patients, diagnosed with isolated congenital anosmia (10 men, 22 women) and 36 age-matched healthy controls (15 men, 21 women) was reanalyzed. In result, men and women without a sense of smell reported enhanced social insecurity, but with different consequences: Men who were born without a sense of smell exhibit a strongly reduced number of sexual relationships and women are affected such that they feel less secure about their partner. This emphasizes the importance of the sense of smell for intimate relationships. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Using smartphone technology to reduce health impacts from atmospheric environmental hazards

    Science.gov (United States)

    Johnston, F. H.; Wheeler, A. J.; Williamson, G. J.; Campbell, S. L.; Jones, P. J.; Koolhof, I. S.; Lucani, C.; Cooling, N. B.; Bowman, D. M. J. S.

    2018-04-01

    Background: Global environmental change is exacerbating human vulnerability to adverse atmospheric conditions including air pollution, aeroallergens such as pollen, and extreme weather events. Public information and advisories are a central component of responses to mitigate the human impacts of environmental hazards. Digital technologies are emerging as a means of providing personalised, timely and accessible warnings. Method: We describe AirRater, an integrated online platform that combines symptom surveillance, environmental monitoring, and notifications of changing environmental conditions via a free smartphone app. It was developed and launched in Tasmania, Australia (population 510 000), with the aim of reducing health impacts and improving quality of life in people with conditions such as asthma and allergic rhinitis. We present environmental data, user uptake and results from three online evaluation surveys conducted during the first 22 months of operation, from October 2015 through August 2017. Results: There were 3,443 downloads of the app from all regions of Tasmania. Of the 1,959 individuals who registered, 79% reported having either asthma or allergic rhinitis. Downloads increased during adverse environmental conditions and following publicity. Symptom reports per active user were highest during spring (72%), lowest in autumn (37%) and spiked during periods of reduced air quality. In response to online surveys, most users reported that the app was useful and had improved their understanding of how environmental conditions affect their health, and in some cases had prompted action such as the timely use of medication. Conclusion: Active engagement and consistent positive feedback from users demonstrates the potential for considerable individual, clinical and wider public health benefits from integrated and personalised monitoring systems such as AirRater. The perceived health benefits require objective verification, and such systems need to address

  4. Using ARM Measurements to Understand and Reduce the Double ITCZ Biases in the Community Atmospheric Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Minghua [Stony Brook Univ., NY (United States)

    2016-12-08

    that features a spurious double Inter-tropical Convergence Zone (ITCZ) in most models. This work is recently published in Yu et al. (2016). Interannual variation of ITCZ south of the eastern equatorial Pacific: By analyzing data from satellites, field measurements and atmospheric reanalysis, we have characterized the interannual variation of boreal spring precipitation in the eastern tropical Pacific and found the cause of the observed interannual variability. We have shown that ITCZ in this region can occur as a single ITCZ along the Equator, single ITCZ north of the Equator, single ITCZ south of the Equator, and double ITCZ on both sides of the Equator. We have found that convective instability only plays a secondary role in the ITCZ interannual variability. Instead, the remote impact of the Pacific basin-wide SST on the horizontal gradient of surface pressure and wind convergence is the primary driver of this interannual variability. Results point to the need to include moisture convergence in convection schemes to improve the simulation of precipitation in the eastern tropical Pacific. This result has been recently submitted for publication (Yu and Zhang 2016). 2. Improvement of model parameterizations to reduce the double ITCZ bias We analyzed the current status of climate model performance in simulating precipitation in the equatorial Pacific. We have found that the double ITCZ bias has not been reduced in CMIP5 models relative to CMIP4 models. We have characterized the dynamic structure of the common bias by using precipitation, sea surface temperature, surface winds and sea-level. Results are published in Zhang et al. (2015): Since cumulus convection plays a significant role in the double ITCZ behavior in models, we have used measurements from ARM and other sources to carry out a systematic analysis of the roles of shallow and deep convection in the CAM. We found that in both CAM4 and CAM5, when the intensity of deep convection decreases as a result of

  5. Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees.

    Science.gov (United States)

    Ziska, Lewis H; Pettis, Jeffery S; Edwards, Joan; Hancock, Jillian E; Tomecek, Martha B; Clark, Andrew; Dukes, Jeffrey S; Loladze, Irakli; Polley, H Wayne

    2016-04-13

    At present, there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide, Ca However, whether Ca-induced declines in nutritional quality are also occurring for pollinator food sources is unknown. Flowering late in the season, goldenrod (Solidago spp.) pollen is a widely available autumnal food source commonly acknowledged by apiarists to be essential to native bee (e.g. Bombus spp.) and honeybee (Apis mellifera) health and winter survival. Using floral collections obtained from the Smithsonian Natural History Museum, we quantified Ca-induced temporal changes in pollen protein concentration of Canada goldenrod (Solidago canadensis), the most wide spread Solidago taxon, from hundreds of samples collected throughout the USA and southern Canada over the period 1842-2014 (i.e. a Ca from approx. 280 to 398 ppm). In addition, we conducted a 2 year in situtrial of S. Canadensis populations grown along a continuous Ca gradient from approximately 280 to 500 ppm. The historical data indicated a strong significant correlation between recent increases in Ca and reductions in pollen protein concentration (r(2)= 0.81). Experimental data confirmed this decrease in pollen protein concentration, and indicated that it would be ongoing as Ca continues to rise in the near term, i.e. to 500 ppm (r(2)= 0.88). While additional data are needed to quantify the subsequent effects of reduced protein concentration for Canada goldenrod on bee health and population stability, these results are the first to indicate that increasing Ca can reduce protein content of a floral pollen source widely used by North American bees. © 2016 The Author(s).

  6. Coordinated activation of PTA-ACS and TCA cycles strongly reduces overflow metabolism of acetate in Escherichia coli.

    Science.gov (United States)

    Peebo, Karl; Valgepea, Kaspar; Nahku, Ranno; Riis, Gethe; Oun, Mikk; Adamberg, Kaarel; Vilu, Raivo

    2014-06-01

    Elimination of acetate overflow in aerobic cultivation of Escherichia coli would improve many bioprocesses as acetate accumulation in the growth environment leads to numerous negative effects, e.g. loss of carbon, inhibition of growth, target product synthesis, etc. Despite many years of studies, the mechanism and regulation of acetate overflow are still not completely understood. Therefore, we studied the growth of E. coli K-12 BW25113 and several of its mutant strains affecting acetate-related pathways using the continuous culture method accelerostat (A-stat) at various specific glucose consumption rates with the aim of diminishing acetate overflow. Absolute quantitative exo-metabolome and proteome analyses coupled to metabolic flux analysis enabled us to demonstrate that onset of acetate overflow can be postponed and acetate excretion strongly reduced in E. coli by coordinated activation of phosphotransacetylase-acetyl-CoA synthetase (PTA-ACS) and tricarboxylic acid (TCA) cycles. Fourfold reduction of acetate excretion (2 vs. 8 % from total carbon) at fastest growth compared to wild type was achieved by deleting the genes responsible for inactivation of acetyl-CoA synthetase protein (pka) and TCA cycle regulator arcA. The Δpka ΔarcA strain did not accumulate any other detrimental by-product besides acetate and showed identical μ max and only ~5 % lower biomass yield compared to wild type. We conclude that a fine-tuned coordination between increasing the recycling capabilities of acetate in the PTA-ACS node through a higher concentration of active acetate scavenging Acs protein and downstream metabolism throughput in the TCA cycle is necessary for diminishing overflow metabolism of acetate in E. coli and achieving higher target product production in bioprocesses.

  7. Impact of reduced atmospheric CO2 and varied potassium supply on carbohydrate and potassium distribution in grapevine and grape berries (Vitis vinifera L.).

    Science.gov (United States)

    Coetzee, Zelmari A; Walker, Rob R; Deloire, Alain J; Barril, Célia; Clarke, Simon J; Rogiers, Suzy Y

    2017-11-01

    To assess the robustness of the apparent sugar-potassium relationship during ripening of grape berries, a controlled-environment study was conducted on Shiraz vines involving ambient and reduced (by 34%) atmospheric CO 2 concentrations, and standard and increased (by 67%) soil potassium applications from prior to the onset of ripening. The leaf net photoassimilation rate was decreased by 35% in the reduced CO 2 treatment. The reduction in CO 2 delayed the onset of ripening, but at harvest the sugar content of the berry pericarp was similar to that of plants grown in ambient conditions. The potassium content of the berry pericarp in the reduced CO 2 treatment was however higher than for the ambient CO 2 . Berry potassium, sugar and water content were strongly correlated, regardless of treatments, alluding to a ternary link during ripening. Root starch content was lower under reduced CO 2 conditions, and therefore likely acted as a source of carbohydrates during berry ripening. Root carbohydrate reserve replenishment could also have been moderated under reduced CO 2 at the expense of berry ripening. Given that root potassium concentration was less in the vines grown in the low CO 2 atmosphere, these results point toward whole-plant fine-tuning of carbohydrate and potassium partitioning aimed at optimising fruit ripening. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. Use of Atmospheric Budget to Reduce Uncertainty in Estimated Water Availability over South Asia from Different Reanalyses

    Science.gov (United States)

    Sebastian, Dawn Emil; Pathak, Amey; Ghosh, Subimal

    2016-07-01

    Disagreements across different reanalyses over South Asia result into uncertainty in assessment of water availability, which is computed as the difference between Precipitation and Evapotranspiration (P-E). Here, we compute P-E directly from atmospheric budget with divergence of moisture flux for different reanalyses and find improved correlation with observed values of P-E, acquired from station and satellite data. We also find reduced closure terms for water cycle computed with atmospheric budget, analysed over South Asian landmass, when compared to that obtained with individual values of P and E. The P-E value derived with atmospheric budget is more consistent with energy budget, when we use top-of-atmosphere radiation for the same. For analysing water cycle, we use runoff from Global Land Data Assimilation System, and water storage from Gravity Recovery and Climate Experiment. We find improvements in agreements across different reanalyses, in terms of inter-annual cross correlation when atmospheric budget is used to estimate P-E and hence, emphasize to use the same for estimations of water availability in South Asia to reduce uncertainty. Our results on water availability with reduced uncertainty over highly populated monsoon driven South Asia will be useful for water management and agricultural decision making.

  9. Use of Atmospheric Budget to Reduce Uncertainty in Estimated Water Availability over South Asia from Different Reanalyses.

    Science.gov (United States)

    Sebastian, Dawn Emil; Pathak, Amey; Ghosh, Subimal

    2016-07-08

    Disagreements across different reanalyses over South Asia result into uncertainty in assessment of water availability, which is computed as the difference between Precipitation and Evapotranspiration (P-E). Here, we compute P-E directly from atmospheric budget with divergence of moisture flux for different reanalyses and find improved correlation with observed values of P-E, acquired from station and satellite data. We also find reduced closure terms for water cycle computed with atmospheric budget, analysed over South Asian landmass, when compared to that obtained with individual values of P and E. The P-E value derived with atmospheric budget is more consistent with energy budget, when we use top-of-atmosphere radiation for the same. For analysing water cycle, we use runoff from Global Land Data Assimilation System, and water storage from Gravity Recovery and Climate Experiment. We find improvements in agreements across different reanalyses, in terms of inter-annual cross correlation when atmospheric budget is used to estimate P-E and hence, emphasize to use the same for estimations of water availability in South Asia to reduce uncertainty. Our results on water availability with reduced uncertainty over highly populated monsoon driven South Asia will be useful for water management and agricultural decision making.

  10. On the strong and selective isotope effect in the UV excitation of N2 with implications toward the nebula and Martian atmosphere.

    Science.gov (United States)

    Muskatel, B H; Remacle, F; Thiemens, Mark H; Levine, R D

    2011-04-12

    Isotopic effects associated with molecular absorption are discussed with reference to natural phenomena including early solar system processes, Titan and terrestrial atmospheric chemistry, and Martian atmospheric evolution. Quantification of the physicochemical aspects of the excitation and dissociation processes may lead to enhanced understanding of these environments. Here we examine a physical basis for an additional isotope effect during photolysis of molecular nitrogen due to the coupling of valence and Rydberg excited states. The origin of this isotope effect is shown to be the coupling of diabatic electronic states of different bonding nature that occurs after the excitation of these states. This coupling is characteristic of energy regimes where two or more excited states are nearly crossing or osculating. A signature of the resultant isotope effect is a window of rapid variation in the otherwise smooth distribution of oscillator strengths vs. frequency. The reference for the discussion is the numerical solution of the time dependent Schrödinger equation for both the electronic and nuclear modes with the light field included as part of the Hamiltonian. Pumping is to all extreme UV dipole-allowed, valence and Rydberg, excited states of N(2). The computed absorption spectra are convoluted with the solar spectrum to demonstrate the importance of including this isotope effect in planetary, interstellar molecular cloud, and nebular photochemical models. It is suggested that accidental resonance with strong discrete lines in the solar spectrum such as the CIII line at 97.703 nm can also have a marked effect.

  11. A reduced order model to analytically infer atmospheric CO2 concentration from stomatal and climate data

    Science.gov (United States)

    Konrad, Wilfried; Katul, Gabriel; Roth-Nebelsick, Anita; Grein, Michaela

    2017-06-01

    To address questions related to the acceleration or deceleration of the global hydrological cycle or links between the carbon and water cycles over land, reliable data for past climatic conditions based on proxies are required. In particular, the reconstruction of palaeoatmospheric CO2 content (Ca) is needed to assist the separation of natural from anthropogenic Ca variability and to explore phase relations between Ca and air temperature Ta time series. Both Ta and Ca are needed to fingerprint anthropogenic signatures in vapor pressure deficit, a major driver used to explain acceleration or deceleration phases in the global hydrological cycle. Current approaches to Ca reconstruction rely on a robust inverse correlation between measured stomatal density in leaves (ν) of many plant taxa and Ca. There are two methods that exploit this correlation: The first uses calibration curves obtained from extant species assumed to represent the fossil taxa, thereby restricting the suitable taxa to those existing today. The second is a hybrid eco-hydrological/physiological approach that determines Ca with the aid of systems of equations based on quasi-instantaneous leaf-gas exchange theories and fossil stomatal data collected along with other measured leaf anatomical traits and parameters. In this contribution, a reduced order model (ROM) is proposed that derives Ca from a single equation incorporating the aforementioned stomatal data, basic climate (e.g. temperature), estimated biochemical parameters of assimilation and isotope data. The usage of the ROM is then illustrated by applying it to isotopic and anatomical measurements from three extant species. The ROM derivation is based on a balance between the biochemical demand and atmospheric supply of CO2 that leads to an explicit expression linking stomatal conductance to internal CO2 concentration (Ci) and Ca. The resulting expression of stomatal conductance from the carbon economy of the leaf is then equated to another

  12. Studying the influence of strong meteorological disturbances in the Earth's lower atmosphere on variations of ionospheric parameters in the Asian region of Russia

    Science.gov (United States)

    Chernigovskaya, Marina; Kurkin, Vladimir; Orlov, Igor; Oinats, Alexey; Sharkov, Eugenii

    2010-05-01

    Short-period temporal variations of ionospheric parameters were analyzed to study probabilities of manifestation of strong meteorological disturbances in the Earth's lower atmosphere in variations of upper atmosphere parameters in a zone far removed from a disturbance source. In the analysis, we used data on maximum observed frequencies (MOF) of oblique sounding (OS) signals along Norilsk-Irkutsk, Magadan-Irkutsk, and Khabarovsk-Irkutsk paths in East Siberia and the Far East. These data were obtained during solar minimum at equinoxes (March, September) in 2008-2009. Analyzing effects of wave disturbances in ionospheric parameters, we take into account helio-geomagnetic and meteorological conditions in regions under study to do an effective separation between disturbances associated with magnetospheric-ionospheric coupling and those induced by the influence of the lower atmosphere on the upper one. The frequency analysis we conducted revealed time intervals with higher intensity of short-period oscillations which may have been interpreted as manifestation of large-scale traveling ionospheric disturbances (TIDs) whose sources were internal gravity waves (IGWs) with periods of 1-5 hours. The complex analysis of helio-geomagnetic, ionospheric, and atmospheric data as well as data on tropical cyclones established that the detected TIDs were unrelated to helio-geomagnetic disturbances (2008-2009 exhibited solar minimum and quiet geomagnetic conditions). The analysis of other potential sources of the observed short-period wave disturbances shows that observed TIDs do not always coincide in time with passage of local meteorological fronts through the region of subionospheric points of OS paths and are not associated with passage of solar terminator. An attempt was made to connect a number of detected TIDs with ionospheric responses to tropical cyclones (TC) which were in active phase in the north-west of the Pacific Ocean during the periods considered. A considerable

  13. Reduced biomass burning emissions reconcile conflicting estimates of the post-2006 atmospheric methane budget.

    Science.gov (United States)

    Worden, John R; Bloom, A Anthony; Pandey, Sudhanshu; Jiang, Zhe; Worden, Helen M; Walker, Thomas W; Houweling, Sander; Röckmann, Thomas

    2017-12-20

    Several viable but conflicting explanations have been proposed to explain the recent ~8 p.p.b. per year increase in atmospheric methane after 2006, equivalent to net emissions increase of ~25 Tg CH 4 per year. A concurrent increase in atmospheric ethane implicates a fossil source; a concurrent decrease in the heavy isotope content of methane points toward a biogenic source, while other studies propose a decrease in the chemical sink (OH). Here we show that biomass burning emissions of methane decreased by 3.7 (±1.4) Tg CH 4 per year from the 2001-2007 to the 2008-2014 time periods using satellite measurements of CO and CH 4 , nearly twice the decrease expected from prior estimates. After updating both the total and isotopic budgets for atmospheric methane with these revised biomass burning emissions (and assuming no change to the chemical sink), we find that fossil fuels contribute between 12-19 Tg CH 4 per year to the recent atmospheric methane increase, thus reconciling the isotopic- and ethane-based results.

  14. The future role of reforestation in reducing buildup of atmospheric CO2

    International Nuclear Information System (INIS)

    Marland, G.

    1993-01-01

    Among the options posed for mitigating the buildup of atmospheric CO 2 is planting new forest areas to sequester carbon from the atmosphere. Among the questions of interest in modeling the global carbon cycle is the extent to which reforestation is likely to succeed in providing physical removal of CO 2 from the atmosphere. There are many strategies for using forest land to mitigate the atmospheric buildup of CO 2 : decreasing the rate at which forests are cleared for other land uses, increasing the density of carbon storage in existing forests, improving the rate and efficiency at which forest products are used in the place of other energy intensive products, substitution of renewable wood fuels for fossil fuels, improved management of forests and agroforestry, and increasing the amount of land in standing forest. Because increasing the area of forests has social, political, and economic limitations; in addition to physical limitations; it is hard to envision a large increase in forest area except where there are associated economic benefits. The authors speculation is that, over the next several decades, the forest strategies most likely to be pursued for the express purpose of CO 2 mitigation are those which provide more or more-efficient substitution of forest products for energy or energy-intensive resources and that the physical accumulation of additional carbon in forests will be of lesser importance

  15. Reduced early growing season freezing resistance in alpine treeline plants under elevated atmospheric CO2.

    NARCIS (Netherlands)

    Martin, M.; Gavazov, K.S.; Körner, S.; Rixen, C.

    2010-01-01

    The frequency of freezing events during the early growing season and the vulnerability to freezing of plants in European high-altitude environments could increase under future atmospheric and climate change. We tested early growing season freezing sensitivity in 10 species, from four plant

  16. Toward Reducing Uncertainties in Biospheric Carbon Uptake in the American West: An Atmospheric Perspective

    Science.gov (United States)

    Lin, J. C.; Stephens, B. B.; Mallia, D.; Wu, D.; Jacobson, A. R.

    2015-12-01

    Despite the need for an understanding of terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO2 concentrations, knowledge of such fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where lack of observations combined with difficulties in their interpretation lead to significant uncertainties. Yet mountainous regions are also where significant forest cover and biomass are found—areas that have the potential to serve as carbon sinks. In particular, understanding carbon fluxes in the American West is of critical importance for the U.S. carbon budget, as the large area and biomass indicate potential for carbon sequestration. However, disturbances such as drought, insect outbreak, and wildfires in this region can introduce significant perturbations to the carbon cycle and thereby affect the amount of carbon sequestered by vegetation in the Rockies. To date, there have been few atmospheric CO2 observations in the American Rockies due to a combination of difficulties associated with logistics and interpretation of the measurements in the midst of complex terrain. Among the few sites are those associated with NCAR's Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON). As CO2 observations in mountainous areas increase in the future, it is imperative that they can be properly interpreted to yield information about biospheric carbon fluxes. In this paper, we will present CO2 observations from RACCOON, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes in the Western U.S. from these observations. We show that atmospheric models can significantly misinterpret the CO2 observations, leading to large errors in the retrieved biospheric fluxes, due to erroneous atmospheric flows. Recommendations for ways to minimize such errors and properly link the CO2 concentrations to biospheric fluxes are discussed.

  17. Reduced ratings of physical and relational aggression for youths with a strong cultural identity: evidence from the Naskapi people.

    Science.gov (United States)

    Flanagan, Tara; Iarocci, Grace; D'Arrisso, Alexandra; Mandour, Tarek; Tootoosis, Curtis; Robinson, Sandy; Burack, Jacob A

    2011-08-01

    Minority youth in general, and Aboriginal youth in particular, are at increased statistical risk for being perpetrators or victims of aggression. We examined the potential protective aspect of cultural identity in relation to peer ratings of physical and relational aggression and factors typically associated with each among almost the entire cohort of Naskapi youths from Kawawachikamach, Québec. Hierarchical multiple regressions revealed that a strong identity with their own Native culture predicted less perceived physical and social aggression by their peers. These findings are discussed in the context of the role of a positive affiliation with ancestral culture for the diminishment of adolescent aggression and for general adaptive development and well-being. Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  18. Current-horn suppression for reduced coherent-synchrotron-radiation-induced emittance growth in strong bunch compression

    Directory of Open Access Journals (Sweden)

    T. K. Charles

    2017-03-01

    Full Text Available Control of coherent synchrotron radiation (CSR-induced emittance growth is essential in linear accelerators designed to deliver very high brightness electron beams. Extreme current values at the head and tail of the electron bunch, resulting from strong bunch compression, are responsible for large CSR production leading to significant transverse projected emittance growth. The Linac Coherent Light Source (LCLS truncates the head and tail current spikes which greatly improves free electron laser (FEL performance. Here we consider the underlying dynamics that lead to formation of current spikes (also referred to as current horns, which has been identified as caustics forming in electron trajectories. We present a method to analytically determine conditions required to avoid the caustic formation and therefore prevent the current spikes from forming. These required conditions can be easily met, without increasing the transverse slice emittance, through inclusion of an octupole magnet in the middle of a bunch compressor.

  19. Using Atmosphere-Forest Measurements To Examine The Potential For Reduced Downwind Dose

    International Nuclear Information System (INIS)

    Viner, B.

    2015-01-01

    A 2-D dispersion model was developed to address how airborne plumes interact with the forest at Savannah River Site. Parameters describing turbulence and mixing of the atmosphere within and just above the forest were estimated using measurements of water vapor or carbon dioxide concentration made at the Aiken AmeriFlux tower for a range of stability and seasonal conditions. Stability periods when the greatest amount of mixing of an airborne plume into the forest were found for 1) very unstable environments, when atmospheric turbulence is usually at a maximum, and 2) very stable environments, when the plume concentration at the forest top is at a maximum and small amounts of turbulent mixing can move a substantial portion of the plume into the forest. Plume interactions with the forest during stable periods are of particular importance because these conditions are usually considered the worst-case scenario for downwind effects from a plume. The pattern of plume mixing into the forest was similar during the year except during summer when the amount of plume mixed into the forest was nearly negligible for all but stable periods. If the model results indicating increased deposition into the forest during stable conditions can be confirmed, it would allow for a reduction in the limitations that restrict facility operations while maintaining conservative estimates for downwind effects. Continuing work is planned to confirm these results as well as estimate specific deposition velocity values for use in toolbox models used in regulatory roles.

  20. The bean rhizosphere Pseudomonas aeruginosa strain RZ9 strongly reduces Fusarium culmorum growth and infectiveness of plant roots

    Energy Technology Data Exchange (ETDEWEB)

    Haddoudi, I.; Sendi, Y.; Batnini, M.; Romdhane, S.B.; Mhadhbi, H.; Mrabet, M.

    2017-07-01

    A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW) by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51%) and root DW (up to 60%) for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110%) and root DWs (29% and 67%), in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans.

  1. The bean rhizosphere Pseudomonas aeruginosa strain RZ9 strongly reduces Fusarium culmorum growth and infectiveness of plant roots

    Directory of Open Access Journals (Sweden)

    Imen Haddoudi

    2017-07-01

    Full Text Available A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51% and root DW (up to 60% for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110% and root DWs (29% and 67%, in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans.

  2. The effect of a strong stellar flare on the atmospheric chemistry of an earth-like planet orbiting an M dwarf.

    Science.gov (United States)

    Segura, Antígona; Walkowicz, Lucianne M; Meadows, Victoria; Kasting, James; Hawley, Suzanne

    2010-09-01

    Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high-energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwarf AD Leonis (AD Leo), simulating the effects from both UV radiation and protons on the atmospheric chemistry of a hypothetical, Earth-like planet located within its habitable zone. Based on observations of solar proton events and the Neupert effect, we estimated a proton flux associated with the flare of 5.9 × 10⁸ protons cm⁻² sr⁻¹ s⁻¹ for particles with energies >10 MeV. Then we calculated the abundance of nitrogen oxides produced by the flare by scaling the production of these compounds during a large solar proton event called the Carrington event. The simulations were performed with a 1-D photochemical model coupled to a 1-D radiative/convective model. Our results indicate that the UV radiation emitted during the flare does not produce a significant change in the ozone column depth of the planet. When the action of protons is included, the ozone depletion reaches a maximum of 94% two years after the flare for a planet with no magnetic field. At the peak of the flare, the calculated UV fluxes that reach the surface, in the wavelength ranges that are damaging for life, exceed those received on Earth during less than 100 s. Therefore, flares may not present a direct hazard for life on the surface of an orbiting habitable planet. Given that AD Leo is one of the most magnetically active M dwarfs known, this conclusion should apply to planets around other M dwarfs with lower levels of chromospheric activity.

  3. New reduced-dimensionality models for efficient quantum-mechanical description of ultrafast strong-field phenomena

    International Nuclear Information System (INIS)

    Silaev, A.A.; Ryabikin, M.Yu.; Vvedenskii, N.V.

    2010-01-01

    Complete text of publication follows. The development of theoretical approaches to the description of strong-field phenomena caused by ultrashort laser pulses is optical for studying the interaction of atoms and molecules with intense laser fields. In this work, we address two phenomena which attract much attention and can be observed under similar experimental conditions, namely, when a gas is ionized by ultrashort laser pulse. The first phenomenon is the excitation of high-order harmonics of the driving field frequency in the electron current, which leads to the generation of vacuum ultraviolet and soft X-ray radiation, as well as the attosecond pulse production. The second phenomenon is the excitation of a quasi-dc residual current in the laser-produced plasma, which results in the generation of radiation having a frequency below the laser one, e.g., terahertz waves. We present new one-dimensional (1D) and two-dimensional (2D) quantum-mechanical models for the description of such phenomena for the case a hydrogen (H) atom, and the generalization of these models to the case of various noble-gas atoms. The shape of the electrostatic potential produced by an atomic ion is shown to influence significantly the rates of the processes in the dynamics of atomic electron, and even more, the rates of the tunneling and above-barrier ionization, which is of utmost importance for the considered phenomena. The results of solving the time-dependent Schroedinger equation with the 1D and 2D potentials, which we propose, are compared with the results of the ab initio three-dimensional calculations for the H atom. We find the regions of laser pulse parameters, where the results obtained with proposed models have much better accuracy than the results provided by the models used earlier. Acknowledgements. This work was supported by the Russian Foundation for Basic Research, the Presidential Council on Grants of the Russian Federation, the Ministry of Education and Science of the

  4. Recent changes in the oxidized to reduced nitrogen ratio in atmospheric precipitation

    Science.gov (United States)

    Kurzyca, Iwona; Frankowski, Marcin

    2017-10-01

    In this study, the characteristics of precipitation in terms of various nitrogen forms (NO3-, NO2-, NH4+, Norganic, Ntotal) is presented. The samples were collected in the areas of different anthropogenic pressure (urban area vs. ecologically protected woodland area, ∼30 km distant from each other; Wielkopolska region, Poland). Based on the Nox and Nred emission profiles (Nox/Nred ratio), temporal and spatial comparison was carried out. For both sites, during a decade of observation, more than 60% of samples had higher contribution of N-NH4+ than N-NO3-, the amount of N-NO2- was negligible, and organic nitrogen amounted to 30% of total nitrogen content which varied up to 16 mg/l. The precipitation events w ith high concentration of nitrogen species were investigated in terms of possible local and remote sources of nitrogen (synoptic meteorology), to indicate the areas which can act as potential sources of N-compounds. Based on the chemometric analysis, it was found that Nred implies Nox and vice versa, due to interactions between them in the atmosphere. Taking into account the analysis of precipitation occurring simultaneously in both locations (about 50% of all rainfall episodes), it was observed that such factor as anthropogenic pressure differentiates but does not determine the chemical composition of precipitation in the investigated areas (urban vs. woodland area; distance of ∼30 km). Thermodynamics of the atmosphere had a significant impact on concentrations of N-NO3- and N-NH4+ in precipitation, as well as the circulation of air masses and remote N sources responsible for transboundary inflow of pollutants.

  5. Some reduced ternary and quaternary oxides of molybdenum. A family of compounds with strong metal-metal bonds

    International Nuclear Information System (INIS)

    Torardi, C.C.; McCarley, R.E.

    1981-01-01

    Several new, reduced ternary and quaternary oxides of molybdenum are reported, each containing molybdenum in an average oxidation state 2 sealed in Mo tubes held at 1100 0 C for ca. 7 days. Refinement of the substructure of the new compound Ba 0 62 Mo 4 O 6 was based on an orthorhombic cells, with a = 9.509(2), b = 9.825(2), c = 2.853(1) A, Z = 2 in space group Pbam; weak supercell reflections indicate the true structure has c = 8(2.853) A. The chief structural feature is closely related to that of NaMo 4 O 6 which consists of infinite chains of Mo 6 octahedral clusters fused on opposite edges, bridged on the outer edges by O atoms and crosslinked by Mo-O-Mo bonding to create four-sided tunnels in which the Ba 2+ ions are located. The structure of Ba 1 13 Mo 8 O 16 is triclinic, a = 7.311(1), b = 7.453(1), c = 5.726(1) A, α = 101.49(2), β = 99.60(2), γ = 89.31(2) 0 , Z = 1, space group P1. It is a low-symmetry, metal-metal bonded variant of the hollandite structure, in which two different infinite chains, built up from Mo 4 O 8 2- and Mo 4 O 8 0 26- cluster units, respectively, are interlinked via Mo-O-Mo bridge bonding to create again four-sided tunnels in which the Ba 2+ ions reside. Other compounds prepared and characterized by analyses and x-ray powder diffraction data are Pb/sub x/Mo 4 O 6 (x approx. 0.6), LiZn 2 Mo 3 O 8 , , CaMo 5 O 8 , K 2 Mo 12 O 19 , and Na 2 Mo 12 O 19

  6. Increased expression of CD133 and reduced dystroglycan expression are strong predictors of poor outcome in colon cancer patients

    Directory of Open Access Journals (Sweden)

    Coco Claudio

    2012-09-01

    Full Text Available Abstract Background Expression levels of CD133, a cancer stem cell marker, and of the α-subunit of the dystroglycan (α-DG complex, have been previously reported to be altered in colorectal cancers. Methods Expression levels of CD133 and α-DG were assessed by immunohistochemistry in a series of colon cancers and their prognostic significance was evaluated. Results Scattered cells positive for CD133 were rarely detected at the bases of the crypts in normal colonic mucosa while in cancer cells the median percentage of positive cells was 5% (range 0–80. A significant correlation was observed with pT parameter and tumor stage but not with tumor grade and N status. Recurrence and death from disease were significantly more frequent in CD133-high expressing tumors and Kaplan-Meier curves showed a significant separation between high vs low expressor groups for both disease-free (p = 0.002 and overall (p = 0.008 survival. Expression of α-DG was reduced in a significant fraction of tumors but low α-DG staining did not correlate with any of the classical clinical-pathological parameters. Recurrence and death from the disease were significantly more frequent in α-DG-low expressing tumors and Kaplan-Meier curves showed a significant separation between high vs low expressor tumors for both disease-free (p = 0.02 and overall (p = 0.02 survival. Increased expression of CD133, but not loss of α-DG, confirmed to be an independent prognostic parameters at a multivariate analysis associated with an increased risk of recurrence (RR = 2.4; p = 0.002 and death (RR = 2.3; p = 0.003. Conclusions Loss of α-DG and increased CD133 expression are frequent events in human colon cancer and evaluation of CD133 expression could help to identify high-risk colon cancer patients.

  7. Thyme oil vapour and modified atmosphere packaging reduce anthracnose incidence and maintain fruit quality in avocado.

    Science.gov (United States)

    Sellamuthu, Periyar Selvam; Mafune, Mpho; Sivakumar, Dharini; Soundy, Puffy

    2013-09-01

    Postharvest application of prochloraz fungicide is commercially practiced to control anthracnose, a postharvest disease in avocado. Increasing consumer concern regarding food safety and demand for organically produced fruits make it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry. A combination of modified atmosphere packaging (MAP; ∼8% CO₂, 2% O₂) plus thyme oil (TO) was evaluated on the incidence and severity of anthracnose, physiological disorders (grey pulp, vascular browning), fruit quality parameters (L*, h°, firmness, weight loss) and sensory parameters (taste, texture, flavour and overall acceptance), phenylalanine ammonia-lyase (PAL) enzyme activity, total phenolic compounds, flavonoid contents and antioxidant activity in avocados ('Fuerte' and 'Hass' cultivars) held at 10 °C cold storage for 18 days and thereafter, ripened at 25 °C for 5-10 days. Stand-alone MAP, commercial treatment (prochloraz 0.05%) and untreated (control) fruit were included for comparison. MAP + TO treatment significantly (P anthracnose, grey pulp, vascular browning, weight loss and loss of fruit firmness, and showed acceptable taste, flavour, texture and higher overall acceptance, increased PAL activity, total phenolic compounds, flavonoid contents and antioxidant activity, after ripening at 25 °C followed by cold storage at 10 °C. This investigation recommends MAP + TO combination treatment as a suitable alternative to the currently adopted prochloraz application. © 2013 Society of Chemical Industry.

  8. Atmospheric contamination

    International Nuclear Information System (INIS)

    Gruetter, Juerg

    1997-01-01

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

  9. Increasing atmospheric deposition nitrogen and ammonium reduced microbial activity and changed the bacterial community composition of red paddy soil.

    Science.gov (United States)

    Zhou, Fengwu; Cui, Jian; Zhou, Jing; Yang, John; Li, Yong; Leng, Qiangmei; Wang, Yangqing; He, Dongyi; Song, Liyan; Gao, Min; Zeng, Jun; Chan, Andy

    2018-03-27

    Atmospheric deposition nitrogen (ADN) increases the N content in soil and subsequently impacts microbial activity of soil. However, the effects of ADN on paddy soil microbial activity have not been well characterized. In this study, we studied how red paddy soil microbial activity responses to different contents of ADN through a 10-months ADN simulation on well managed pot experiments. Results showed that all tested contents of ADN fluxes (27, 55, and 82kgNha -1 when its ratio of NH 4 + /NO 3 - -N (R N ) was 2:1) enhanced the soil enzyme activity and microbial biomass carbon and nitrogen and 27kgNha -1 ADN had maximum effects while comparing with the fertilizer treatment. Generally, increasing of both ADN flux and R N (1:2, 1:1 and 2:1 with the ADN flux of 55kgNha -1 ) had similar reduced effects on microbial activity. Furthermore, both ADN flux and R N significantly reduced soil bacterial alpha diversity (pADN flux and R N were the main drivers in shaping paddy soil bacteria community. Overall, the results have indicated that increasing ADN flux and ammonium reduced soil microbial activity and changed the soil bacterial community. The finding highlights how paddy soil microbial community response to ADN and provides information for N management in paddy soil. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. XPS and ToF-SIMS analysis of natural rubies and sapphires heat-treated in a reducing (5 mol% H 2/Ar) atmosphere

    Science.gov (United States)

    Achiwawanich, S.; James, B. D.; Liesegang, J.

    2008-12-01

    Surface effects on Mong Hsu rubies and Kanchanaburi sapphires after heat treatment in a controlled reducing atmosphere (5 mol% H 2/Ar) have been investigated using advanced surface science techniques including X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Visual appearance of the gemstones is clearly affected by the heat treatment in a reducing atmosphere. Kanchanaburi sapphires, in particular, exhibit Fe-containing precipitates after the heat treatment which have not been observed in previous studies under an inert atmosphere. Significant correlation between changes in visual appearance of the gemstones and variations in surface concentration of trace elements, especially Ti and Fe are observed. The XPS and ToF-SIMS results suggest that; (1) a reducing atmosphere affects the oxidation state of Fe; (2) dissociation of Fe-Ti interaction may occur during heat treatment.

  11. XPS and ToF-SIMS analysis of natural rubies and sapphires heat-treated in a reducing (5 mol% H{sub 2}/Ar) atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Achiwawanich, S. [Department of Physics, La Trobe University, VIC 3086 (Australia); Centre for Materials and Surface Science, La Trobe University, VIC 3086 (Australia); James, B.D. [Centre for Materials and Surface Science, La Trobe University, VIC 3086 (Australia); Department of Chemistry, La Trobe University, VIC 3086 (Australia); Liesegang, J. [Department of Physics, La Trobe University, VIC 3086 (Australia); Centre for Materials and Surface Science, La Trobe University, VIC 3086 (Australia)], E-mail: J.Liesegang@latrobe.edu.au

    2008-12-30

    Surface effects on Mong Hsu rubies and Kanchanaburi sapphires after heat treatment in a controlled reducing atmosphere (5 mol% H{sub 2}/Ar) have been investigated using advanced surface science techniques including X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Visual appearance of the gemstones is clearly affected by the heat treatment in a reducing atmosphere. Kanchanaburi sapphires, in particular, exhibit Fe-containing precipitates after the heat treatment which have not been observed in previous studies under an inert atmosphere. Significant correlation between changes in visual appearance of the gemstones and variations in surface concentration of trace elements, especially Ti and Fe are observed. The XPS and ToF-SIMS results suggest that; (1) a reducing atmosphere affects the oxidation state of Fe; (2) dissociation of Fe-Ti interaction may occur during heat treatment.

  12. Reduced tillage and cover crops as a strategy for mitigating atmospheric CO2 increase through soil organic carbon sequestration in dry Mediterranean agroecosystems.

    Science.gov (United States)

    Almagro, María; Garcia-Franco, Noelia; de Vente, Joris; Boix-Fayos, Carolina; Díaz-Pereira, Elvira; Martínez-Mena, María

    2016-04-01

    , respectively) than under CT treatment (399 g C-CO2 m-2 yr-1) in site 2. Tillage operations had a rapid but short-lived effect on soil CO2 efflux rates, with no significant influence on the annual soil CO2 emissions. The larger amounts of plant biomass incorporated into soil annually in the reduced tillage treatments compared to the conventional tillage treatment promoted soil aggregation and the physico-chemical soil organic carbon stabilization while soil CO2 emissions did not significantly increase. According to our results, reduced-tillage is strongly recommended as a beneficial SLM strategy for mitigating atmospheric CO2 increase through soil carbon sequestration and stabilization in semiarid Mediterranean agroecosystems.

  13. Bacterial ice nuclei impact cloud lifetime and radiative properties and reduce atmospheric heat loss in the BRAMS simulation model

    International Nuclear Information System (INIS)

    Costa, Tassio S; Gonçalves, Fábio L T; Yamasoe, Marcia A; Martins, Jorge A; Morris, Cindy E

    2014-01-01

    This study examines the effect of the bacterial species Pseudomonas syringae acting as ice nuclei (IN) on cloud properties to understand its impact on local radiative budget and heating rates. These bacteria may become active IN at temperatures as warm as −2 °C. Numerical simulations were developed using the Brazilian Regional Atmospheric Model System (BRAMS). To investigate the isolated effect of bacterial IN, four scenarios were created considering only homogeneous and bacterial ice nucleation, with 1, 10 and 100 IN per cubic meter of cloud volume and one with no bacteria. Moreover, two other scenarios were generated: the BRAMS default parameterization and its combination with bacterial IN. The model reproduced a strong convective cell over São Paulo on 3 March 2003. Results showed that bacterial IN may change cloud evolution as well as its microphysical properties, which in turn influence cloud radiative properties. For example, the reflected shortwave irradiance over an averaged domain in a scenario considering bacterial IN added to the BRAMS default parameterization was 14% lower than if bacteria were not considered. Heating rates can also be impacted, especially due to differences in cloud lifetime. Results suggest that the omission of bacterial IN in numerical models, including global cloud models, could neglect relevant ice nucleation processes that potentially influence cloud radiative properties. (letter)

  14. Direct night-time ejection of particle-phase reduced biogenic sulfur compounds from the ocean to the atmosphere.

    Science.gov (United States)

    Gaston, Cassandra J; Furutani, Hiroshi; Guazzotti, Sergio A; Coffee, Keith R; Jung, Jinyoung; Uematsu, Mitsuo; Prather, Kimberly A

    2015-04-21

    The influence of oceanic biological activity on sea spray aerosol composition, clouds, and climate remains poorly understood. The emission of organic material and gaseous dimethyl sulfide (DMS) from the ocean represents well-documented biogenic processes that influence particle chemistry in marine environments. However, the direct emission of particle-phase biogenic sulfur from the ocean remains largely unexplored. Here we present measurements of ocean-derived particles containing reduced sulfur, detected as elemental sulfur ions (e.g., (32)S(+), (64)S2(+)), in seven different marine environments using real-time, single particle mass spectrometry; these particles have not been detected outside of the marine environment. These reduced sulfur compounds were associated with primary marine particle types and wind speeds typically between 5 and 10 m/s suggesting that these particles themselves are a primary emission. In studies with measurements of seawater properties, chlorophyll-a and atmospheric DMS concentrations were typically elevated in these same locations suggesting a biogenic source for these sulfur-containing particles. Interestingly, these sulfur-containing particles only appeared at night, likely due to rapid photochemical destruction during the daytime, and comprised up to ∼67% of the aerosol number fraction, particularly in the supermicrometer size range. These sulfur-containing particles were detected along the California coast, across the Pacific Ocean, and in the southern Indian Ocean suggesting that these particles represent a globally significant biogenic contribution to the marine aerosol burden.

  15. An identical-location transmission electron microscopy study on the degradation of Pt/C nanoparticles under oxidizing, reducing and neutral atmosphere

    International Nuclear Information System (INIS)

    Dubau, L.; Castanheira, L.; Berthomé, G.; Maillard, F.

    2013-01-01

    This study shows that the predominant degradation mechanism of Pt/Vulcan XC72 electrocatalysts strongly depends on the nature of the gas atmosphere and of the upper potential limit used in accelerated stress tests (ASTs). The morphological changes of Pt/Vulcan XC72 nanoparticles were studied by identical location transmission electron microscopy (IL-TEM), following accelerated stress tests in different potential ranges and under various gas atmospheres. X-ray photoelectron spectroscopy was used to probe changes in carbon surface chemistry. Whereas minor changes were detected under neutral atmosphere (Ar) and low potential limit conditions (0.05 2 ). With an increase of the upper potential limit to 1.23 V vs. RHE, the trends observed previously were maintained but 3D Ostwald ripening strongly overlapped with the three other degradation mechanisms, precluding any identification of the dominant mechanism

  16. Strong correlation in acene sheets from the active-space variational two-electron reduced density matrix method: effects of symmetry and size.

    Science.gov (United States)

    Pelzer, Kenley; Greenman, Loren; Gidofalvi, Gergely; Mazziotti, David A

    2011-06-09

    Polyaromatic hydrocarbons (PAHs) are a class of organic molecules with importance in several branches of science, including medicine, combustion chemistry, and materials science. The delocalized π-orbital systems in PAHs require highly accurate electronic structure methods to capture strong electron correlation. Treating correlation in PAHs has been challenging because (i) traditional wave function methods for strong correlation have not been applicable since they scale exponentially in the number of strongly correlated orbitals, and (ii) alternative methods such as the density-matrix renormalization group and variational two-electron reduced density matrix (2-RDM) methods have not been applied beyond linear acene chains. In this paper we extend the earlier results from active-space variational 2-RDM theory [Gidofalvi, G.; Mazziotti, D. A. J. Chem. Phys. 2008, 129, 134108] to the more general two-dimensional arrangement of rings--acene sheets--to study the relationship between geometry and electron correlation in PAHs. The acene-sheet calculations, if performed with conventional wave function methods, would require wave function expansions with as many as 1.5 × 10(17) configuration state functions. To measure electron correlation, we employ several RDM-based metrics: (i) natural-orbital occupation numbers, (ii) the 1-RDM von Neumann entropy, (iii) the correlation energy per carbon atom, and (iv) the squared Frobenius norm of the cumulant 2-RDM. The results confirm a trend of increasing polyradical character with increasing molecular size previously observed in linear PAHs and reveal a corresponding trend in two-dimensional (arch-shaped) PAHs. Furthermore, in PAHs of similar size they show significant variations in correlation with geometry. PAHs with the strictly linear geometry (chains) exhibit more electron correlation than PAHs with nonlinear geometries (sheets).

  17. RE-EVALUATING WASP-12b: STRONG EMISSION AT 2.315 μm, DEEPER OCCULTATIONS, AND AN ISOTHERMAL ATMOSPHERE

    International Nuclear Information System (INIS)

    Crossfield, Ian J. M.; Barman, Travis; Hansen, Brad M. S.; Tanaka, Ichi; Kodama, Tadayuki

    2012-01-01

    We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 μm) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% ± 0.06%, corresponding to a brightness temperature of 3640 ± 230 K; second, recent Spitzer/Infrared Array Camera and Hubble Space Telescope/Wide Field Camera 3 observations; and third, a recently observed star only 1'' from WASP-12, which has diluted previous observations and which we further characterize here. We correct past WASP-12b eclipse measurements for the presence of this object, and we revisit the interpretation of WASP-12b's dilution-corrected emission spectrum. The resulting planetary emission spectrum is well approximated by a blackbody, and consequently our primary conclusion is that the planet's infrared photosphere is nearly isothermal. Thus, secondary eclipse spectroscopy is relatively ill suited to constrain WASP-12b's atmospheric abundances, and transmission spectroscopy may be necessary to achieve this goal.

  18. Growing Platinum-Ruthenium-Tin ternary alloy nanoparticles on reduced graphene oxide for strong ligand effect toward enhanced ethanol oxidation reaction.

    Science.gov (United States)

    Xia, Qing Qing; Zhang, Lian Ying; Zhao, Zhi Liang; Li, Chang Ming

    2017-11-15

    Uniform Pt 1 Ru 0.5 Sn 0.5 ternary alloy nanoparticles are in situ deposited on reduced graphene oxide (Pt 1 Ru 0.5 Sn 0.5 -RGO) through its functional groups and defects as nucleation sites to greatly electrocatalyze ethanol oxidation reaction for much higher mass current densities, larger apparent specific current densities and better stability than commercial Pt-C catalyst (Pt-C(commer)). Mechanistic studies indicate that the excellent electrocatalytic activity and anti-poisoning are resulted from a strong ligand effect of the ternary alloy components, in which the charge transfer is boosted while decreasing the density of states close to the Fermi level of Pt to reduce bond energy between Pt and CO-like adsorbates for greatly improved anti-poisoning ability. This work holds a great promise to fabricate a high performance anode catalyst with a low Pt loading for direct ethanol fuel cells. Copyright © 2017. Published by Elsevier Inc.

  19. Effects of Dopant on the Dielectric Properties of CaZrO3 Ceramic Sintered in a Reducing Atmosphere

    Science.gov (United States)

    Lee, W. S.; Su, C. Y.; Lee, Y. C.; Lin, S. P.; Yang, Tony

    2006-07-01

    In this study, the influence of CaZrO3 doped with three dopants, SiO2, MnO, and Nb2O5, and then sintered in a reducing atmosphere on microstructure, phase formation, and electrical properties is investigated. SiO2 plays the role of sintering aid to enhance the density of CaZrO3 leading to better performance of electrical properties as a function of SiO2 content. MnO, and Nb2O5 were incorporated into the Zr-site of CaZrO3 to make stoichometric CaZrO3 into non-stoichiometric CaZrO3 with Zr excess resulting in the formation of a second phase, CaZr4O9, which has a lower dielectric constant (13) in comparison with that of the main phase of CaZrO3 (32). Thus, the dielectric constant of CaZrO3 doped with Nb2O5, or MnO is decreased markedly. In addition, Mn+2 incorporated into Zr-sites of CaZrO3 plays the role of acceptor, which compensates for the number of conduction electrons and contributes to better performance of electrical properties such as insulation resistance and \\tanδ. Conversely, Nb+5 incorporated into Zr-sites of CaZrO3 plays the role of donor and provides more conduction electrons, leading to poor performance of electrical properties.

  20. Enhancement of thermoelectric power factor of Sr2CoMoO6 double perovskite by annealing in reducing atmosphere

    Science.gov (United States)

    Tanwar, Khagesh; Saxena, Mandvi; Maiti, Tanmoy

    2017-10-01

    In general, n-type thermoelectric materials are rather difficult to design. This study particularly pivoted on designing potential environmentally benign oxides based n-type thermoelectric material. We synthesized Sr2CoMoO6 (SCMO) polycrystalline ceramics via the solid-state synthesis route. XRD, SEM, and thermoelectric measurements were carried out for phase constitution, microstructure analysis, and to determine its potential for thermoelectric applications. As-sintered SCMO sample showed an insulator like behavior till 640 °C after which it exhibited an n-type non-degenerate semiconductor behavior followed by a p-n type conduction switching. To stabilize a high temperature n-type behavior, annealing of SCMO in reducing atmosphere (H2) at 1000 °C was carried out. After annealing, the SCMO demonstrated an n-type semiconductor behavior throughout the temperature range of measurement. The electrical conductivity (σ) and the power factor (S2σ) were found to be increased manifold in the annealed SCMO double perovskite.

  1. Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

    Directory of Open Access Journals (Sweden)

    A. A. Turnipseed

    2017-06-01

    Full Text Available A new solid-phase scrubber for use in conventional ozone (O3 photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100–130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm, the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH, volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S. Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

  2. Expression of DIAPH1 is up-regulated in colorectal cancer and its down-regulation strongly reduces the metastatic capacity of colon carcinoma cells.

    Science.gov (United States)

    Lin, Yuan-Na; Izbicki, Jakob R; König, Alexandra; Habermann, Jens K; Blechner, Christine; Lange, Tobias; Schumacher, Udo; Windhorst, Sabine

    2014-04-01

    In most cases, metastatic colorectal cancer is not curable, thus new approaches are necessary to identify novel targets for colorectal cancer therapy. Actin-binding-proteins (ABPs) directly regulate motility of metastasising tumor cells, and for cortactin an association with colon cancer metastasis has been already shown. However, as its depletion only incompletely inhibits metastasis, additional, more suitable cellular targets have to be identified. Here we analyzed expression of the ABPs, DIAPH1, VASP, N-WASP, and fascin in comparison with cortactin and found that, besides cortactin, DIAPH1 was expressed with the highest frequency (63%) in colorectal cancer. As well as cortactin, DIAPH1 was not detectable in normal colon tissue and expression of both proteins was positively correlated with metastasis of colorectal cancer. To analyse the mechanistic role of DIAPH1 for metastasis of colon carcinoma cells in comparison with cortactin, expression of the proteins was stably down-regulated in the human colon carcinoma cell lines HT-29, HROC-24 and HCT-116. Analysis of metastasis of colon carcinoma cells in SCID mice revealed that depletion of DIAPH1 reduced metastasis 60-fold and depletion of cortactin 16-fold as compared with control cells. Most likely the stronger effect of DIAPH1 depletion on colon cancer metastasis is due to the fact that in vitro knock down of DIAPH1 impaired all steps of metastasis; adhesion, invasion and migration while down-regulation of cortactin only reduced adhesion and invasion. This very strong reducing effect of DIAPH1 depletion on colon carcinoma cell metastasis makes the protein a promising therapeutic target for individualized colorectal cancer therapy. © 2013 UICC.

  3. There is not yet strong evidence that exercise regimens other than pelvic floor muscle training can reduce stress urinary incontinence in women: a systematic review.

    Science.gov (United States)

    Bø, Kari; Herbert, Robert D

    2013-09-01

    What evidence is there for alternative exercises to specific pelvic floor muscle training for treatment of stress urinary incontinence in women? A systematic review was conducted with searches of PubMed and PEDro to January 2013. The quality of randomised trials was evaluated using the PEDro scale. Each type of exercise was classified as being in a Development Phase, Testing Phase, or Refinement and Dissemination Phase. Women with stress or mixed urinary incontinence with predominantly stress urinary incontinence. Exercise regimens other than pelvic floor muscle training. The primary outcome was urinary leakage. Seven randomised controlled trials were found: three on abdominal training, two on the Paula method, and two on Pilates exercise. The methodological quality score ranged between 4 and 8 with a mean of 5.7. There was no convincing evidence for the effect of these exercise regimens so they remain in the Testing Phase. Because no randomised trials were found for posture correction, breathing exercise, yoga, Tai Chi, and general fitness training, these were classified as being in the Development Phase. There is not yet strong evidence that alternative exercise regimens can reduce urinary leakage in women with stress urinary incontinence. Alternative exercise regimens should not yet be recommended for use in clinical practice for women with stress urinary incontinence. Copyright © 2013 Australian Physiotherapy Association. Published by .. All rights reserved.

  4. Densification and Grain Growth during Early-stage Sintering of Ce0.9Gd0.1O1.95-δ in Reducing Atmosphere

    DEFF Research Database (Denmark)

    He, Zeming; Yuan, Hao; Glasscock, Julie

    2010-01-01

    The present work investigates the processes of densification and grain growth of Ce0.9Gd0.1O1.95-δ (CGO10) during sintering in reducing atmosphere. Sintering variables were experimentally characterized and analyzed using defect chemistry and sintering constitutive laws. Based on the achieved...

  5. Reducing errors in aircraft atmospheric inversion estimates of point-source emissions: the Aliso Canyon natural gas leak as a natural tracer experiment

    Science.gov (United States)

    Gourdji, S. M.; Yadav, V.; Karion, A.; Mueller, K. L.; Conley, S.; Ryerson, T.; Nehrkorn, T.; Kort, E. A.

    2018-04-01

    Urban greenhouse gas (GHG) flux estimation with atmospheric measurements and modeling, i.e. the ‘top-down’ approach, can potentially support GHG emission reduction policies by assessing trends in surface fluxes and detecting anomalies from bottom-up inventories. Aircraft-collected GHG observations also have the potential to help quantify point-source emissions that may not be adequately sampled by fixed surface tower-based atmospheric observing systems. Here, we estimate CH4 emissions from a known point source, the Aliso Canyon natural gas leak in Los Angeles, CA from October 2015–February 2016, using atmospheric inverse models with airborne CH4 observations from twelve flights ≈4 km downwind of the leak and surface sensitivities from a mesoscale atmospheric transport model. This leak event has been well-quantified previously using various methods by the California Air Resources Board, thereby providing high confidence in the mass-balance leak rate estimates of (Conley et al 2016), used here for comparison to inversion results. Inversions with an optimal setup are shown to provide estimates of the leak magnitude, on average, within a third of the mass balance values, with remaining errors in estimated leak rates predominantly explained by modeled wind speed errors of up to 10 m s‑1, quantified by comparing airborne meteorological observations with modeled values along the flight track. An inversion setup using scaled observational wind speed errors in the model-data mismatch covariance matrix is shown to significantly reduce the influence of transport model errors on spatial patterns and estimated leak rates from the inversions. In sum, this study takes advantage of a natural tracer release experiment (i.e. the Aliso Canyon natural gas leak) to identify effective approaches for reducing the influence of transport model error on atmospheric inversions of point-source emissions, while suggesting future potential for integrating surface tower and

  6. Six commercially viable ways to remove CO2 from the atmosphere and/or reduce CO2 emissions

    NARCIS (Netherlands)

    Schuiling, O.; de Boer, P.L.

    2013-01-01

    Background The burning of fossil fuels is the main cause of rising CO2 levels of the atmosphere. This will probably result in climate change. Another consequence is ocean acidification. Although these consequences are not yet proven beyond doubt, the risk of doing nothing is too large. The simplest

  7. Study of the thermal transformations of Co- and Fe-exchanged zeolites A and X by 'in situ' XRD under reducing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Ronchetti, Silvia, E-mail: silvia.ronchetti@polito.it [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Turcato, Elisa Aurelia; Delmastro, Alessandro [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Esposito, Serena; Ferone, Claudio; Pansini, Michele [Laboratorio Materiali del Dipartimento di Meccanica, Strutture, Ambiente e Territorio, Facolta di Ingegneria dell' Universita di Cassino, Via G. Di Biasio 43, 03043 Cassino (Italy); Onida, Barbara; Mazza, Daniele [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2010-06-15

    'In situ' high temperature X-ray diffraction under reducing atmosphere is used for the first time to study the thermal stability and transformations of Co- and Fe-exchanged A and X zeolites. TG-DTA and 'ex situ' XRD characterization were also carried out. The temperature of incipient crystallization of metallic phase was found to be 700 {sup o}C in Fe-zeolites and 800 {sup o}C in Co-zeolites. Moreover, ex situ X-ray experiments, after thermal treatment both under inert and reducing atmosphere, revealed the formation of ceramic phases upon the thermal collapse of the zeolitic framework. Metal nanoparticles were obtained by reduction and the size of metal clusters was found to range between 24 and 40 nm.

  8. Spectroscopic investigations of high-energy-density plasma transformations in a simulated early reducing atmosphere containing methane, nitrogen and water

    Czech Academy of Sciences Publication Activity Database

    Civiš, M.; Ferus, M.; Knížek, A.; Kubelík, P.; Karnas, M.; Španěl, P.; Dryahina, K.; Shestivska, V.; Juha, Libor; Skřehot, P.; Laitl, V.; Civiš, S.

    2016-01-01

    Roč. 18, č. 39 (2016), s. 27317-27325 ISSN 1463-9076 R&D Projects: GA MŠk LG15013; GA MŠk(CZ) LM2015083 Institutional support: RVO:61389021 Keywords : HIGH-POWER LASER * INDUCED DIELECTRIC-BREAKDOWN * EARTHS EARLY ATMOSPHERE Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 4.123, year: 2016

  9. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  10. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  11. Carbonation of alkaline paper mill waste to reduce CO{sub 2} greenhouse gas emissions into the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lopez, R. [Laboratoire de Geophysique Interne et Tectonophysique, CNRS-OSUG-UJF, Universite Joseph Fourier Grenoble I, Maison des Geosciences, BP 53, 38041 Grenoble Cedex (France); Department of Geology, University of Huelva, Campus ' El Carmen' , 21071 Huelva (Spain)], E-mail: rafael.perez@dgeo.uhu.es; Montes-Hernandez, G. [Laboratoire de Geophysique Interne et Tectonophysique, CNRS-OSUG-UJF, Universite Joseph Fourier Grenoble I, Maison des Geosciences, BP 53, 38041 Grenoble Cedex (France); Nieto, J.M. [Department of Geology, University of Huelva, Campus ' El Carmen' , 21071 Huelva (Spain); Renard, F. [Laboratoire de Geodynamique des Chaines Alpines, CNRS-OSUG-UJF, Universite Joseph Fourier Grenoble I, Maison des Geosciences, BP 53, 38041 Grenoble Cedex (France); Physics of Geological Processes, University of Oslo (Norway); Charlet, L. [Laboratoire de Geophysique Interne et Tectonophysique, CNRS-OSUG-UJF, Universite Joseph Fourier Grenoble I, Maison des Geosciences, BP 53, 38041 Grenoble Cedex (France)

    2008-08-15

    The global warming of Earth's near-surface, air and oceans in recent decades is a direct consequence of anthropogenic emission of greenhouse gases into the atmosphere such as CO{sub 2}, CH{sub 4}, N{sub 2}O and CFCs. The CO{sub 2} emissions contribute approximately 60% to this climate change. This study investigates experimentally the aqueous carbonation mechanisms of an alkaline paper mill waste containing about 55 wt% portlandite (Ca(OH){sub 2}) as a possible mineralogical CO{sub 2} sequestration process. The overall carbonation reaction includes the following steps: (1) Ca release from portlandite dissolution, (2) CO{sub 2} dissolution in water and (3) CaCO{sub 3} precipitation. This CO{sub 2} sequestration mechanism was supported by geochemical modelling of final solutions using PHREEQC software, and observations by scanning electron microscope and X-ray diffraction of final reaction products. According to the experimental protocol, the system proposed would favour the total capture of approx. 218 kg of CO{sub 2} into stable calcite/ton of paper waste, independently of initial CO{sub 2} pressure. The final product from the carbonation process is a calcite (ca. 100 wt%)-water dispersion. Indeed, the total captured CO{sub 2} mineralized as calcite could be stored in degraded soils or even used for diverse industrial applications. This result demonstrates the possibility of using the alkaline liquid-solid waste for CO{sub 2} mitigation and reduction of greenhouse effect gases into the atmosphere.

  12. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells

    Science.gov (United States)

    Lan, Rong; Cowin, Peter I.; Sengodan, Sivaprakash; Tao, Shanwen

    2016-08-01

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3-δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3-δ (SFCN) exhibits a conductivity of 63 Scm-1and 60 Scm-1 at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3-δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3-δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3-δ as the cathode achieved a power density of 423 mWcm-2 at 700 °C indicating that SFCN is a promising anode for SOFCs.

  13. Griffiths-like phase in high TC perovskite La2FeReO6 prepared in a controlled reducing atmosphere

    Science.gov (United States)

    Kaipamagalath, Aswathi; Palakkal, Jasnamol P.; Varma, Manoj R.

    2018-05-01

    The perovskite La2FeReO6 is prepared by solid-state reaction method. Calcination was done in a controlled reducing atmosphere. The structure of the compound is found to be orthorhombic with Pbnm space group. From the DC magnetic studies, the transition temperature (TC) of La2FeReO6 is found to be at 729 K. A Griffiths-like phase is present in the material with ferromagnetic short-range correlations above TC up to the Griffiths temperature TG = 863 K.

  14. Reduced ultrafine particle levels in São Paulo's atmosphere during shifts from gasoline to ethanol use.

    Science.gov (United States)

    Salvo, Alberto; Brito, Joel; Artaxo, Paulo; Geiger, Franz M

    2017-07-18

    Despite ethanol's penetration into urban transportation, observational evidence quantifying the consequence for the atmospheric particulate burden during actual, not hypothetical, fuel-fleet shifts, has been lacking. Here we analyze aerosol, meteorological, traffic, and consumer behavior data and find, empirically, that ambient number concentrations of 7-100-nm diameter particles rise by one-third during the morning commute when higher ethanol prices induce 2 million drivers in the real-world megacity of São Paulo to substitute to gasoline use (95% confidence intervals: +4,154 to +13,272 cm -3 ). Similarly, concentrations fall when consumers return to ethanol. Changes in larger particle concentrations, including US-regulated PM2.5, are statistically indistinguishable from zero. The prospect of increased biofuel use and mounting evidence on ultrafines' health effects make our result acutely policy relevant, to be weighed against possible ozone increases. The finding motivates further studies in real-world environments. We innovate in using econometrics to quantify a key source of urban ultrafine particles.The biofuel ethanol has been introduced into urban transportation in many countries. Here, by measuring aerosols in São Paulo, the authors find that high ethanol prices coincided with an increase in harmful nanoparticles by a third, as drivers switched from ethanol to cheaper gasoline, showing a benefit of ethanol.

  15. Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere

    Science.gov (United States)

    Becker, S.; Halsall, C. J.; Tych, W.; Kallenborn, R.; Schlabach, M.; Manø, S.

    2012-05-01

    An extensive database of organochlorine (OC) pesticide concentrations measured at the Norwegian Arctic monitoring station at Ny-Ålesund, Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to isolate underlying inter-annual trends. Although a simple comparison of annual mean concentrations (1994-2005) suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p,p'-DDT. Indeed, HCB shows an increase from 2003-2005. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cis-chlordane (TC/CC) indicate a shift from primary sources, to more "weathered" secondary sources, whereas an increasing trend in o,p'-DDT/p,p'-DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from "new" sources.

  16. Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere

    Directory of Open Access Journals (Sweden)

    S. Becker

    2012-05-01

    Full Text Available An extensive database of organochlorine (OC pesticide concentrations measured at the Norwegian Arctic monitoring station at Ny-Ålesund, Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB, and to isolate underlying inter-annual trends. Although a simple comparison of annual mean concentrations (1994–2005 suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p,p'-DDT. Indeed, HCB shows an increase from 2003–2005. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cis-chlordane (TC/CC indicate a shift from primary sources, to more "weathered" secondary sources, whereas an increasing trend in o,p'-DDT/p,p'-DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from "new" sources.

  17. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  18. Application of a Reduced Order Kalman Filter to Initialize a Coupled Atmosphere-Ocean Model: Impact on the Prediction of El Nino

    Science.gov (United States)

    Ballabrera-Poy, Joaquim; Busalacchi, Antonio J.; Murtugudde, Ragu

    2000-01-01

    A reduced order Kalman Filter, based on a simplification of the Singular Evolutive Extended Kalman (SEEK) filter equations, is used to assimilate observed fields of the surface wind stress, sea surface temperature and sea level into the nonlinear coupled ocean-atmosphere model. The SEEK filter projects the Kalman Filter equations onto a subspace defined by the eigenvalue decomposition of the error forecast matrix, allowing its application to high dimensional systems. The Zebiak and Cane model couples a linear reduced gravity ocean model with a single vertical mode atmospheric model of Zebiak. The compatibility between the simplified physics of the model and each observed variable is studied separately and together. The results show the ability of the model to represent the simultaneous value of the wind stress, SST and sea level, when the fields are limited to the latitude band 10 deg S - 10 deg N. In this first application of the Kalman Filter to a coupled ocean-atmosphere prediction model, the sea level fields are assimilated in terms of the Kelvin and Rossby modes of the thermocline depth anomaly. An estimation of the error of these modes is derived from the projection of an estimation of the sea level error over such modes. This method gives a value of 12 for the error of the Kelvin amplitude, and 6 m of error for the Rossby component of the thermocline depth. The ability of the method to reconstruct the state of the equatorial Pacific and predict its time evolution is demonstrated. The method is shown to be quite robust for predictions I up to six months, and able to predict the onset of the 1997 warm event fifteen months before its occurrence.

  19. Can green roofs reduce urban heat stress in vulnerable urban communities: A coupled atmospheric and social modeling approach

    Science.gov (United States)

    Sharma, A.; Woodruff, S.; Budhathoki, M.; Hamlet, A. F.; Fernando, H. J. S.; Chen, F.

    2017-12-01

    Urban areas provide organized, engineered, sociological and economical infrastructure designed to provide a high quality of life, but the implementation and management of urban infrastructure has been a continued challenge. Increasing urbanization, warming climate, as well as anthropogenic heat emissions that accompany urban development generates "stress". This rapidly increasing `urban stress' affects the sustainability of cities, making populations more vulnerable to extreme hazards, such as heat. Cities are beginning to extensively use green roofs as a potential urban heat mitigation strategy. This study explores the potential of green roofs to reduce summertime temperatures in the most vulnerable neighborhoods of the Chicago metropolitan area by combining social vulnerability indices (a function of exposure, sensitivity and adaptive capacity), and temperatures from mesoscale model. Numerical simulations using urbanized version the Advanced Research Weather Research and Forecasting (WRF) model were performed to measure rooftop temperatures, a representative variable for exposure in this study. The WRF simulations were dynamically coupled with a green roof algorithm as a part of urban parameterization within WRF. Specifically, the study examines roof surface temperature with changing green roof fractions and how would they help reduce exposure to heat stress for vulnerable urban communities. This study shows an example of applied research that can directly benefit urban communities and be used by urban planners to evaluate mitigation strategies.

  20. Interleukins 1alpha and 1beta secreted by some melanoma cell lines strongly reduce expression of MITF-M and melanocyte differentiation antigens.

    Science.gov (United States)

    Kholmanskikh, Olga; van Baren, Nicolas; Brasseur, Francis; Ottaviani, Sabrina; Vanacker, Julie; Arts, Nathalie; van der Bruggen, Pierre; Coulie, Pierre; De Plaen, Etienne

    2010-10-01

    We report that melanoma cell lines expressing the interleukin-1 receptor exhibit 4- to 10-fold lower levels of mRNA of microphthalmia-associated transcription factor (MITF-M) when treated with interleukin-1beta. This effect is NF-kappaB and JNK-dependent. MITF-M regulates the expression of melanocyte differentiation genes such as MLANA, tyrosinase and gp100, which encode antigens recognized on melanoma cells by autologous cytolytic T lymphocytes. Accordingly, treating some melanoma cells with IL-1beta reduced by 40-100% their ability to activate such antimelanoma cytolytic T lymphocytes. Finally, we observed large amounts of biologically active IL-1alpha or IL-1beta secreted by two melanoma cell lines that did not express MITF-M, suggesting an autocrine MITF-M downregulation. We estimate that approximately 13% of melanoma cell lines are MITF-M-negative and secrete IL-1 cytokines. These results indicate that the repression of melanocyte-differentiation genes by IL-1 produced by stromal cells or by tumor cells themselves may represent an additional mechanism of melanoma immune escape.

  1. Control of substrate oxidation in MOD cerawwwmic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Science.gov (United States)

    Tanaka, Teruya; Muroga, Takeo

    2014-12-01

    An Er2O3 ceramic coating fabricated using the metal-organic decomposition (MOD) method on a Cr2O3-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr2O3 layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of baking. Preprocessing to obtain a Cr2O3 layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr2O3 layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr2O3 and MOD oxide ceramic.

  2. Control of substrate oxidation in MOD ceramic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Teruya, E-mail: teru@nifs.ac.jp; Muroga, Takeo

    2014-12-15

    Highlights: • A Cr{sub 2}O{sub 3} layer was produced on a ferritic steel substrate with a reduced-pressure. • The Cr{sub 2}O{sub 3} layer prevents further substrate oxidation in following coating process. • The Cr{sub 2}O{sub 3} layer has a function as a hydrogen permeation barrier. • A smooth MOD Er{sub 2}O{sub 3} coating was successfully made on the Cr{sub 2}O{sub 3} layer by dip coating. • The Cr{sub 2}O{sub 3} layer would enhance flexibility in MOD coating process and performances. - Abstract: An Er{sub 2}O{sub 3} ceramic coating fabricated using the metal–organic decomposition (MOD) method on a Cr{sub 2}O{sub 3}-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr{sub 2}O{sub 3} layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of <5 × 10{sup −3} Pa and 5 Pa. The Cr{sub 2}O{sub 3} layer was significantly stable even with heat treatment at 700 °C in air. This layer prevented further production of Fe{sub 2}O{sub 3}, which has been considered to degrade coating performance. An MOD Er{sub 2}O{sub 3} coating with a smooth surface was successfully obtained on a Cr{sub 2}O{sub 3}-covered JLF-1 substrate by dip coating followed by drying and baking. Preprocessing to obtain a Cr{sub 2}O{sub 3} layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr{sub 2}O{sub 3} layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr{sub 2}O{sub 3} and MOD oxide ceramic.

  3. Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

    Science.gov (United States)

    Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

    2017-01-01

    Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

  4. Conductivity of SDC and (Li/Na){sub 2}CO{sub 3} composite electrolytes in reducing and oxidising atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Boden, Andreas; Lagergren, Carina; Lindbergh, Goeran [KTH Chemical Science and Engineering, Applied Electrochemistry, SE-100 44 Stockholm (Sweden); Di, Jing; Wang, Cheng Yang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2007-10-25

    Composite electrolytes made of samarium-doped cerium oxide and a mixture of lithium carbonate and sodium carbonate salts are investigated with respect to their structure, morphology and ionic conductivity. The composite electrolytes are considered promising for use in so called intermediate temperature solid oxide fuel cells (IT-SOFC), operating at 400-600 C. The electrolytes are tested in both gaseous anode (reducing) and cathode (oxidising) environments and at different humidities and carbon dioxide partial pressures. For the structure and morphology measurements, it was concluded that no changes occur to the materials after usage. From measurements of melting energies, it was concluded that the melting point of the carbonate salt phase decreases with decreasing fraction of carbonate salt and that a partial melting occurs before the bulk melting point of the salt is reached. For all the composites, two regions may be observed for the conductivity, one below the carbonate salt melting point and one above the melting point. The conductivity is higher when electrolytes are tested in anode gas than when tested in cathode gas, at least for electrolytes with less than half the volume fraction consisting of carbonate salt. The higher the content of carbonate salt phase, the higher the conductivity of the composite for the temperature region above the carbonate melting point. Below the melting point, though, the conductivity does not follow this trend. Calculations on activation energies for the conductivity show no trend or value that indicates a certain transport mechanism for ion transport, either when changing between the different composites or between different gas environments. (author)

  5. Dissolution rates of unirradiated UO2, UO2 doped with 233U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    International Nuclear Information System (INIS)

    Ollila, Kaija; Albinsson, Yngve; Oversby, Virginia; Cowper, Mark

    2003-10-01

    The experimental results given in this report allow us to draw the following conclusions. 1) Tests using unirradiated fuel pellet materials from two different manufacturers gave very different dissolution rates under air atmosphere testing. Tests for fragments of pellets from different pellets made by the same manufacturer gave good agreement. This indicates that details of the manufacturing process have a large effect on the behavior of unirradiated UO 2 in dissolution experiments. Care must be taken in interpreting differences in results obtained in different laboratories because the results may be affected by manufacturing effects. 2) Long-term tests under air atmosphere have begun to show the effects of precipitation. Further testing will be needed before the samples reach steady state. 3) Testing of unirradiated UO 2 in systems containing an iron strip to produce reducing conditions gave [U] less than detection limits ( 235 U added as spike was recovered, indicating that 90% of the spike had precipitated onto the solid sample or the iron strip. 9) Tests of UO 2 pellet materials containing 233 U to provide an alpha decay activity similar to that expected for spent fuel 3000 and 10,000 years after disposal showed that the pellet materials behaved as expected under air atmosphere conditions, showing that the manufacturing method was successful. 10) Early testing of the 233 U-doped materials under reducing conditions showed relatively rapid (30 minute) dissolution of small amounts of U at the start of the puff test procedure. Results of analyses of an acidified fraction of the same solutions after 1 or 2 weeks holding indicate that the solutions were inhomogeneous, indicating the presence of colloidal material or small grains of solid. 11) Samples from the 233 U-doped tests initially indicated dissolution of solid during the first week of testing, with some indication of more rapid dissolution of the material with the higher doping. 12) The second cycle of testing

  6. Forest science and technology to reduce atmospheric greenhouse gases - an overview, with emphasis on carbon in Canada's forests

    International Nuclear Information System (INIS)

    Savidge, R.A.

    2001-01-01

    The forest as a CO 2 sink comprises, in addition to mature and immature trees, C accumulated in understorey plants, animals, forest soils, peat bogs and wetlands. Estimates of how much carbon (C) is entering and leaving a forest ecosystem cannot be obtained merely by estimating gaseous CO 2 fluxes. The C cycle also involves direct transfer of CO 2 to soil in rain and snow, non-photosynthetic or 'dark' fixation of CO 2 by myriad soil and aquatic micro-organisms, roots, fungi and animals, and loss of C in forms other than CO 2 via air, groundwater flow and runoff. The complexity of the carbon cycle challenges us to develop reliably accurate means of inventorying C accumulation in trees. In productive forests the C of wood can be determined by estimating tree merchantable volume and, by density conversion, mass of dry wood. Percentage C in dry wood varies by species and type of wood, but otherwise C of wood can be readily calculated. The C present in foliage, branches, bark and roots can, as a first approximation, be assumed to be equivalent to that in the merchantable boles. National Forestry Database statistics and our elemental analysis data on total carbon in wood were used to determine how much C is present in and being removed annually from Canadian forests. In 1998 Canada extracted 45 million tonnes of C of wood from 0.5% of its more than 244 million hectares (ha) of productive forest area. That annual harvest contained less than 0.001% of the 6400 gigatonnes of C of wood existing in boles of merchantable trees. However, harvesting over the last three centuries has reduced C content m productive forests to well below 50% of their pre-1700 sink capacity. To refill the sink, it is proposed that a ceiling of 50 million tonnes C of wood be set as the annual allowable cut. Mean temperature increases of as much as 8 o C have been forecast for Canada over the next 100 years. The impact of those increases on tree growth and survival will depend not so much on changes

  7. ESCAPING PARTICLE FLUXES IN THE ATMOSPHERES OF CLOSE-IN EXOPLANETS. II. REDUCED MASS-LOSS RATES AND ANISOTROPIC WINDS

    International Nuclear Information System (INIS)

    Guo, J. H.

    2013-01-01

    In Paper I, we presented a one-dimensional hydrodynamic model for the winds of close-in exoplanets. However, close-in exoplanets are tidally locked and irradiated only on the day sides by their host stars. This requires two-dimensional hydrodynamic models with self-consistent radiative transfer calculations. In this paper, for the tidal-locking (two-dimensional radiative transfer) and non-tidal-locking cases (one-dimensional radiative transfer), we constructed a multi-fluid two-dimensional hydrodynamic model with detailed radiative transfer to depict the escape of particles. We found that the tidal forces (the sum of tidal gravity of the star and centrifugal force due to the planetary rotation) supply significant accelerations and result in anisotropic winds. An important effect of the tidal forces is that it severely depresses the outflow of particles near the polar regions where the density and the radial velocity are a factor of a few (ten) smaller than those of the low-latitude regions. As a consequence, most particles escape the surface of the planet from the regions of low latitude. Comparing the tidal-locking and non-tidal-locking cases, we found that their optical depths are very different so that the flows also emerge with a different pattern. In the case of non-tidal locking, the radial velocities at the base of the wind are higher than the meridional velocities. However, in the case of tidal locking, the meridional velocities dominate the flow at the base of the wind, and they can effectively transfer mass and energy from the day sides to the night sides. Further, we also found that the differences of the winds show a middle extent at large radii. This means that the structure of the wind at the base can be changed by the two-dimensional radiative transfer due to large optical depths, but the extent is reduced with an increase in radius. Because the escape is depressed in the polar regions, the mass-loss rate predicted by the non-tidal-locking model, in

  8. Impact of Amazonian deforestation on atmospheric chemistry

    NARCIS (Netherlands)

    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

  9. Strong reducing of the laser focal volume

    CSIR Research Space (South Africa)

    Godin, T

    2011-08-01

    Full Text Available equal to -1 or +1 modeled on the p light rings of the incident TEMp0 beam. The transformation quality of a 30TEM beam into a single-lobed pattern in the focal plane is shown in Fig. 3. It is clear that the intensity pattern of the rectified beam... DOE (blue solid line), rectified 30TEM (red solid line) -3 -2 -1 0 1 2 3 0 1 2 3 4 z=0 z=f DOE Fig. 2 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 0,0 0,2 0,4 0,6 0,8 1,0 TEM30 without DOE "rectified" TEM30 TEM00 In te ns...

  10. Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

  11. Staging atmospheres

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  12. Can Energy Structure Optimization, Industrial Structure Changes, Technological Improvements, and Central and Local Governance Effectively Reduce Atmospheric Pollution in the Beijing–Tianjin–Hebei Area in China?

    Directory of Open Access Journals (Sweden)

    Xinxuan Cheng

    2018-02-01

    Full Text Available Economic growth in the Beijing–Tianjin–Hebei region has been achieved by consuming large amounts of fossil fuels. This produces a large number of pollutants, which damage the physical and mental health of residents, and prevent sustainable economic development. The most urgent task at present is improving the quality of the environment. This paper takes carbon emission as a pollution index, and adopts an extended stochastic impacts by regression on population, affluence, and technology (STIRPAT model in order to study the impact of the optimization of industry structure (in particular the reduction of the proportion of energy-intensive secondary industry, the optimization of the energy structure, and technological improvements on the atmospheric environmental quality. We obtain some important and enlightening discoveries. First of all, the rapid economic growth that has been based on magnanimous fossil fuel consumption is still the main reason for the deterioration of the atmospheric environment. This means that the main driving force of economic growth still comes from high pollution industries, despite a strategy for the transformation of the pattern of economic growth having been proposed for many years. Second, the optimization of the industrial structure has not played a significant role in promoting the reduction of carbon emissions. Through further research, we believe that this may be due to the low-quality development of the third industry. In other words, the traditional service industry related to high energy consumption accounts for a large proportion in regional total output, while the high-end service industry related to small pollution accounts for a relatively small proportion. Third, reducing the consumption of coal and improving the technological level can effectively curb the deterioration of the environmental quality. In addition, we find that transboundary pollution is an important factor affecting the environment in

  13. Scan-Mode Atmospheric-Pressure Plasma Jet Processed Reduced Graphene Oxides for Quasi-Solid-State Gel-Electrolyte Supercapacitors

    Directory of Open Access Journals (Sweden)

    Aliyah R. Hsu

    2018-01-01

    Full Text Available A scanning atmospheric-pressure plasma jet (APPJ is essential for high-throughput large-area and roll-to-roll processes. In this study, we evaluate scan-mode APPJ for processing reduced graphene oxides (rGOs that are used as the electrodes of quasi-solid-state gel-electrolyte supercapacitors. rGO nanoflakes are mixed with ethyl cellulose (EC and terpineol to form pastes for screen-printing. After screen-printing the pastes on carbon cloth, a DC-pulse nitrogen APPJ is used to process the pastes in the scan mode. The maximal temperature attained is ~550 °C with a thermal influence duration of ~10 s per scan. The pastes are scanned by APPJ for 0, 1, 3 and 5 times. X-ray photoelectron spectroscopy (XPS indicates the reduction of C-O binding content as the number of scan increases, suggesting the oxidation/decomposition of EC. The areal capacitance increases and then decreases as the number of scan increases; the best achieved areal capacitance is 15.93 mF/cm2 with one APPJ scan, in comparison to 4.38 mF/cm2 without APPJ processing. The capacitance retention rate of the supercapacitor with the best performance is ~93% after a 1000-cycle cyclic voltammetry (CV test. The optimal number of APPJ scans should enable the proper removal of inactive EC and improved wettability while minimizing the damage caused to rGOs by nitrogen APPJ processing.

  14. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  15. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  16. Jovian atmospheres

    International Nuclear Information System (INIS)

    Allison, M.; Travis, L.D.

    1986-10-01

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

  17. Morphological and physiological responses of two varieties of a highland species (Chenopodium quinoa Willd.) growing under near-ambient and strongly reduced solar UV-B in a lowland location.

    Science.gov (United States)

    González, Juan A; Rosa, Mariana; Parrado, María F; Hilal, Mirna; Prado, Fernando E

    2009-08-03

    Morphological and physiological responses of seedlings to different solar UV-B irradiances were evaluated in two varieties of quinoa (Chenopodium quinoa Willd.), a crop species from Andean region of South America. Cristalina and Chucapaca varieties were grown at 1965m a.s.l in a glasshouse under natural light conditions for 18 days, and then transferred to outdoors under near-ambient (+UV-B) and strongly reduced (-UV-B) solar UV-B radiation. Exposition to -UV-B increased cotyledon area and seedling height in Cristalina variety whereas leaf number decreased compared to +UV-B. By contrast Chucapaca variety was not affected by UV-B treatments. Seedling fresh weight (FW), root length and leaf thickness did not show significant differences between +UV-B and -UV-B treatments. Mesophyll tissue was slightly affected by solar UV-B reduction. Chlorophyll content was differentially affected by UV-B treatments. Under +UV-B the highest value was observed in Cristalina variety, while in Chucapaca it was observed under -UV-B treatment. Chlorophyll content was slightly higher in leaves than in cotyledons, but there was no difference in the distribution pattern. Chlorophyll a/b ratio and carotenoid content did not show significant differences between UV-B treatments. Leaf UVB-absorbing compounds showed significant differences between UV-B treatments in Chucapaca only, while there were no significant differences in Cristalina variety. UVB-absorbing compounds of cotyledons did not show significant differences between +UV-B and -UV-B treatments. Sucrose, glucose and fructose showed different distribution patterns in cotyledons and leaves of the two varieties under near-ambient and strongly reduced UV-B. Results demonstrated that varieties of quinoa exhibit different morphological and physiological responses to changes in solar UV-B irradiance, but these responses cannot be used to predict the sensitivity to solar UV-B during a short-term exposition. Also, this study can be useful to

  18. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  19. Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5

    Science.gov (United States)

    Ogura, Tomoo; Shiogama, Hideo; Watanabe, Masahiro; Yoshimori, Masakazu; Yokohata, Tokuta; Annan, James D.; Hargreaves, Julia C.; Ushigami, Naoto; Hirota, Kazuya; Someya, Yu; Kamae, Youichi; Tatebe, Hiroaki; Kimoto, Masahide

    2017-12-01

    This study discusses how much of the biases in top-of-atmosphere (TOA) radiation and clouds can be removed by parameter tuning in the present-day simulation of a climate model in the Coupled Model Inter-comparison Project phase 5 (CMIP5) generation. We used output of a perturbed parameter ensemble (PPE) experiment conducted with an atmosphere-ocean general circulation model (AOGCM) without flux adjustment. The Model for Interdisciplinary Research on Climate version 5 (MIROC5) was used for the PPE experiment. Output of the PPE was compared with satellite observation data to evaluate the model biases and the parametric uncertainty of the biases with respect to TOA radiation and clouds. The results indicate that removing or changing the sign of the biases by parameter tuning alone is difficult. In particular, the cooling bias of the shortwave cloud radiative effect at low latitudes could not be removed, neither in the zonal mean nor at each latitude-longitude grid point. The bias was related to the overestimation of both cloud amount and cloud optical thickness, which could not be removed by the parameter tuning either. However, they could be alleviated by tuning parameters such as the maximum cumulus updraft velocity at the cloud base. On the other hand, the bias of the shortwave cloud radiative effect in the Arctic was sensitive to parameter tuning. It could be removed by tuning such parameters as albedo of ice and snow both in the zonal mean and at each grid point. The obtained results illustrate the benefit of PPE experiments which provide useful information regarding effectiveness and limitations of parameter tuning. Implementing a shallow convection parameterization is suggested as a potential measure to alleviate the biases in radiation and clouds.

  20. <strong>Neuroeconomics and Health Economicsstrong>/>

    DEFF Research Database (Denmark)

    Larsen, Torben

    2009-01-01

      Objective: Neuroeconomics integrates economics, psychology and neuroscience. Recently, this line of research is summarized in a neuroeconomic model (NeM) which addresses the rehabilitation of important chronic conditions from a new angle as surveyed in this study. Data and Method: Firstly, Ne......://www.integratedhomecare.eu/ . III. In-depth-relaxation is evidenced as the result of regular practice of medical meditation comprising various practical meditation settings by NGOs whereof some are rooted in the religious tradition while other aim to be post-religious. Medical meditation combines savings on health care costs...... with de-stressing benefits as reduced anxiety, less use of stimulants and a reduction of blood pressure which in all increase life-expectancy. Conclusion: Neuroeconomics helps economists to identify dominant health economic interventions that may be overlooked by traditional discipålines   [i] This part...

  1. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

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

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

    Indian Academy of Sciences (India)

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

  3. Proton-oxygen conductivity in substituted perovskites ATi0.95Mo0.05O3-α (A = Ca, Sr, Ba; M = Sc, Mg) in the reducing hydrogen-containing atmospheres

    International Nuclear Information System (INIS)

    Gorelov, V.P.; Balakireva, V.B.; Sharova, N.V.

    1999-01-01

    Electric conductivity depending on temperature, oxygen partial pressure, as well as the number of t i ion transfer and transfer hydrogen numbers in the perovskites ATi 0.95 Mo 0.05 O 3-α (A = Ca, Sr, Ba; M = Sc, Mg) in reducing hydrogen-containing atmospheres in the temperature range of 450-850 deg C have been measured. With the temperature decrease t i increases reaching 1.0 at a temperature of 550 deg C for all compositions. Proton conductivity under conditions of assumed concomitant transfer of either O 2- or OH - has been ascertained [ru

  4. Understanding Microbial Contributions to Planetary Atmosphere

    Science.gov (United States)

    DesMarais, David J.

    2000-01-01

    Should our search of distant, extrasolar planetary atmospheres encounter evidence of life, that evidence will most likely be the gaseous products of microorganisms. Our biosphere was exclusively microbial for over 80 percent of its history and, even today, microbes strongly influence atmospheric composition. Life's greatest environmental impact arises from its capacity for harvesting energy and creating organic matter. Microorganisms catalyze the equilibration of C, S and transition metal species at temperatures where such reactions can be very slow in the absence of life. Sunlight has been harvested through photosynthesis to create enormous energy reservoirs that exist in the form of coexisting reservoirs of reduced, organic C and S stored in Earth's crust, and highly oxidized species (oxygen, sulfate and ferric iron) stored in the crust, oceans and atmosphere. Our civilization taps that storehouse of energy by burning fossil fuels. As astrobiologists, we identify the chemical consequences of distant biospheres as expressed in the atmospheres of their planets. Our approach must recognize that planets, biospheres and atmospheres evolve and change. For example, a tectonically more active early Earth hosted a thermophilic, non-photosynthetic biosphere and a mildly reducing, carbon dioxide-rich and oxygen-poor atmosphere. Microorganisms acquired energy by consuming hydrogen and sulfide and producing a broad array of reduced C and S gases, most notably, methane. Later, diverse types of bacterial photosynthesis developed that enhanced productivity but were incapable of splitting water to produce oxygen. Later, but still prior to 2.6 billion years ago, oxygenic photosynthesis developed. We can expect to encounter distant biospheres that represent various stages of evolution and that coexist with atmospheres ranging from mildly reducing to oxidizing compositions. Accordinaly, we must be prepared to interpret a broad range of atmospheric compositions, all containing

  5. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  6. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  7. Atmosphere Impact Losses

    Science.gov (United States)

    Schlichting, Hilke E.; Mukhopadhyay, Sujoy

    2018-02-01

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

  8. Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5

    Directory of Open Access Journals (Sweden)

    T. Ogura

    2017-12-01

    Full Text Available This study discusses how much of the biases in top-of-atmosphere (TOA radiation and clouds can be removed by parameter tuning in the present-day simulation of a climate model in the Coupled Model Inter-comparison Project phase 5 (CMIP5 generation. We used output of a perturbed parameter ensemble (PPE experiment conducted with an atmosphere–ocean general circulation model (AOGCM without flux adjustment. The Model for Interdisciplinary Research on Climate version 5 (MIROC5 was used for the PPE experiment. Output of the PPE was compared with satellite observation data to evaluate the model biases and the parametric uncertainty of the biases with respect to TOA radiation and clouds. The results indicate that removing or changing the sign of the biases by parameter tuning alone is difficult. In particular, the cooling bias of the shortwave cloud radiative effect at low latitudes could not be removed, neither in the zonal mean nor at each latitude–longitude grid point. The bias was related to the overestimation of both cloud amount and cloud optical thickness, which could not be removed by the parameter tuning either. However, they could be alleviated by tuning parameters such as the maximum cumulus updraft velocity at the cloud base. On the other hand, the bias of the shortwave cloud radiative effect in the Arctic was sensitive to parameter tuning. It could be removed by tuning such parameters as albedo of ice and snow both in the zonal mean and at each grid point. The obtained results illustrate the benefit of PPE experiments which provide useful information regarding effectiveness and limitations of parameter tuning. Implementing a shallow convection parameterization is suggested as a potential measure to alleviate the biases in radiation and clouds.

  9. Pluto's atmosphere

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  10. 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

  11. Stochastic background of atmospheric cascades

    International Nuclear Information System (INIS)

    Wilk, G.; Wlodarczyk, Z.

    1993-01-01

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

  12. Atmospheric dynamics of Earth-like tidally locked aquaplanets

    Directory of Open Access Journals (Sweden)

    Tapio Schneider

    2010-12-01

    Full Text Available We present simulations of atmospheres of Earth-like aquaplanets that are tidally locked to their star, that is, planets whose orbital period is equal to the rotation period about their spin axis, so that one side always faces the star and the other side is always dark. Such simulations are of interest in the study of tidally locked terrestrial exoplanets and as illustrations of how planetary rotation and the insolation distribution shape climate. As extreme cases illustrating the effects of slow and rapid rotation, we consider planets with rotation periods equal to one current Earth year and one current Earth day. The dynamics responsible for the surface climate (e.g., winds, temperature, precipitation and the general circulation of the atmosphere are discussed in light of existing theories of atmospheric circulations. For example, as expected from the increasing importance of Coriolis accelerations relative to inertial accelerations as the rotation rate increases, the winds are approximately isotropic and divergent at leading order in the slowly rotating atmosphere but are predominantly zonal and rotational in the rapidly rotating atmosphere. Free-atmospheric horizontal temperature variations in the slowly rotating atmosphere are generally weaker than in the rapidly rotating atmosphere. Interestingly, the surface temperature on the night side of the planets does not fall below ~240 K in either the rapidly or slowly rotating atmosphere; that is, heat transport from the day side to the night side of the planets efficiently reduces temperature contrasts in either case. Rotational waves and eddies shape the distribution of winds, temperature, and precipitation in the rapidly rotating atmosphere; in the slowly rotating atmosphere, these distributions are controlled by simpler divergent circulations. Both the slowly and rapidly rotating atmospheres exhibit equatorial superrotation. Systematic variation of the planetary rotation rate shows that the

  13. Comparison of the atmospheric- and reduced-pressure HS-SPME strategies for analysis of residual solvents in commercial antibiotics using a steel fiber coated with a multiwalled carbon nanotube/polyaniline nanocomposite.

    Science.gov (United States)

    Ghiasvand, Ali Reza; Nouriasl, Kolsoum; Yazdankhah, Fatemeh

    2018-01-01

    A low-cost, sensitive and reliable reduced-pressure headspace solid-phase microextraction (HS-SPME) setup was developed and evaluated for direct extraction of residual solvents in commercial antibiotics, followed by determination by gas chromatography with flame ionization detection (GC-FID). A stainless steel narrow wire was made porous and adhesive by platinization by a modified electrophoretic deposition method and coated with a polyaniline/multiwalled carbon nanotube nanocomposite. All experimental variables affecting the extraction efficiency were investigated for both atmospheric-pressure and reduced-pressure conditions. Comparison of the optimal experimental conditions and the results demonstrated that the reduced-pressure strategy leads to a remarkable increase in the extraction efficiency and reduction of the extraction time and temperature (10 min, 25 °Ϲ vs 20 min, 40 °Ϲ). Additionally, the reduced-pressure strategy showed better analytical performances compared with those obtained by the conventional HS-SPME-GC-FID method. Limit of detections, linear dynamic ranges, and relative standard deviations of the reduced-pressure HS-SPME procedure for benzene, toluene, ethylbenzene, and xylene (BTEX) in injectable solid drugs were obtained over the ranges of 20-100 pg g -1 , 0.02-40 μg g -1 , and 2.8-10.2%, respectively. The procedure developed was successful for the analysis of BTEX in commercial containers of penicillin, ampicillin, ceftriaxone, and cefazolin. Graphical abstract Schematic representation of the developed RP-HS-SPME setup.

  14. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  15. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  16. Light extinction in the atmosphere

    International Nuclear Information System (INIS)

    Laulainen, N.

    1992-06-01

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

  17. Earth’s Earliest Atmospheres

    Science.gov (United States)

    Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

    2010-01-01

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

  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...

  19. Atmospheric electrodynamics

    International Nuclear Information System (INIS)

    Volland, H.

    1984-01-01

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

  20. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

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

  1. Atmospheric Electricity

    Science.gov (United States)

    Aplin, Karen; Fischer, Georg

    2018-02-01

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

  2. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  3. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  4. Mars: Atmosphere

    Science.gov (United States)

    Moroz, V.; Murdin, P.

    2001-07-01

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

  5. I-129, Kr-85, C-14 and NO/sub x/ removal from spent fuel dissolver off-gas at atmospheric pressure and at reduced off-gas flow

    International Nuclear Information System (INIS)

    Henrich, E.; Huefner, R.

    1981-01-01

    A dissolver off-gas (DOG) system suitable for a LWR, FBR or HTR spent fuel reprocessing plant is described, incorporating the following features: (1) the DOG flow is reduced to a reasonably small volume, using fumeless dissolution conditions, by maintaining high concentrations, the retention procedures are simplified and accompanied by an economic reduction of the equipment size; (2) all process operations are conducted at atmospheric or subatmospheric pressure, including noble gas removal by selective absorption, without using high temperature processes; (3) all processes, except HEPA filtering, are continuous and do not accumulate large amounts of waste nuclides, the DOG process sequence is mutually compatible with itself and with processing in the headend, showing on-line redundancy for the removal of the most radiotoxic nuclides; and (4) the DOG system only deviates slightly from proven technology. The stage of development and relevant results are given both for a lab. scale and a pilot plant scale

  6. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  7. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  8. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

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

  9. Non-LTE profiles of strong solar lines

    Science.gov (United States)

    Schneeberger, T. J.; Beebe, H. A.

    1976-01-01

    The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.

  10. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  11. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  12. Reducing vibration damage claims: Field application of strong public relations and one method of using commonly available seismograph and video taping equipment to document blast vibration regression at the nearest structure

    International Nuclear Information System (INIS)

    Fritzen, M.R.; Fritzen, T.A.

    1994-01-01

    Anytime that blasting operations will be conducted near existing inhabited structures, vibration damage claims are a major concern of the blasting contractor. It has been the authors' experience that even when vibration and airblast levels generated from a blast are well below accepted damage thresholds, damage claims can still arise. The single greatest source of damage claims is the element of surprise associated with not knowing that blasting operations are being conducted nearby. The second greatest source of damage claims arise form the inability to produce accurate and detailed records of all blasting activity which provides evidence that vibration and air blast levels from each blast had been taken by seismic recording equipment. Using a two part plan consisting of extensive public relations followed by a detailed and accurate monitoring and recording of blasting operations has resulted in no substantiated claims of damage since its' incorporation. The authors experience shows that by using this two part process when conducting blasting operations near inhabited structures, unsubstantiated blast vibration damage claims may be significantly reduced

  13. Reducing vibration damage claims: Field application of strong public relations and one method of using commonly available seismograph and video taping equipment to document blast vibration regression at the nearest structure

    Energy Technology Data Exchange (ETDEWEB)

    Fritzen, M.R.; Fritzen, T.A. [Blasting Technology, Inc., Maui, HI (United States)

    1994-12-31

    Anytime that blasting operations will be conducted near existing inhabited structures, vibration damage claims are a major concern of the blasting contractor. It has been the authors` experience that even when vibration and airblast levels generated from a blast are well below accepted damage thresholds, damage claims can still arise. The single greatest source of damage claims is the element of surprise associated with not knowing that blasting operations are being conducted nearby. The second greatest source of damage claims arise form the inability to produce accurate and detailed records of all blasting activity which provides evidence that vibration and air blast levels from each blast had been taken by seismic recording equipment. Using a two part plan consisting of extensive public relations followed by a detailed and accurate monitoring and recording of blasting operations has resulted in no substantiated claims of damage since its` incorporation. The authors experience shows that by using this two part process when conducting blasting operations near inhabited structures, unsubstantiated blast vibration damage claims may be significantly reduced.

  14. 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...

  15. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

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

  16. Atmospheric cooling tower with reduced plume

    International Nuclear Information System (INIS)

    Gautier, D.M.; Lagoutte, A.

    1985-01-01

    The cooling tower, usable in thermal-electric power plants, has a vertical chimney having a central water tower fed with water to be cooled, a pipe network distributing water coming from the water tower and dispersing it in flows streaming down on a packing, and a basin to receive the water cooled by contact with an air flow passing through apertures at the lower part of the chimney and flowing up through the chimney. The cooling tower has inlet air pipes for the said apertures to a zone of the chimney situated beyond the streaming zone, the said pipes being arranged such their surface is swept by water to be cooled [fr

  17. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  18. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  19. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  20. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  1. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

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

  2. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  3. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  4. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  5. Aperture averaging in strong oceanic turbulence

    Science.gov (United States)

    Gökçe, Muhsin Caner; Baykal, Yahya

    2018-04-01

    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

  6. MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

    International Nuclear Information System (INIS)

    Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L.; Steinkirch, Marina von; Calder, Alan C.

    2016-01-01

    The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

  7. MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Steinkirch, Marina von; Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2016-12-01

    The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

  8. Irradiation strongly reduces tumorigenesis of human induced pluripotent stem cells

    International Nuclear Information System (INIS)

    Inui, Shoki; Minami, Kazumasa; Ito, Emiko; Imaizumi, Hiromasa; Mori, Seiji; Koizumi, Masahiko; Fukushima, Satsuki; Miyagawa, Shigeru; Sawa, Yoshiki; Matsuura, Nariaki

    2017-01-01

    Induced pluripotent stem (iPS) cells have demonstrated they can undergo self-renewal, attain pluripotency, and differentiate into various types of functional cells. In clinical transplantation of iPS cells, however, a major problem is the prevention of tumorigenesis. We speculated that tumor formation could be inhibited by means of irradiation. Since the main purpose of this study was to explore the prevention of tumor formation in human iPS (hiPS) cells, we tested the effects of irradiation on tumor-associated factors such as radiosensitivity, pluripotency and cell death in hiPS cells. The irradiated hiPS cells showed much higher radiosensitivity, because the survival fraction of hiPS cells irradiated with 2 Gy was < 10%, and there was no change of pluripotency. Irradiation with 2 and 4 Gy caused substantial cell death, which was mostly the result of apoptosis. Irradiation with 2 Gy was detrimental enough to cause loss of proliferation capability and trigger substantial cell death in vitro. The hiPS cells irradiated with 2 Gy were injected into NOG mice (NOD/Shi-scid, IL-2 Rγnull) for the analysis of tumor formation. The group of mice into which hiPS cells irradiated with 2 Gy was transplanted showed significant suppression of tumor formation in comparison with that of the group into which non-irradiated hiPS cells were transplanted. It can be presumed that this diminished rate of tumor formation was due to loss of proliferation and cell death caused by irradiation. Our findings suggest that tumor formation following cell therapy or organ transplantation induced by hiPS cells may be prevented by irradiation.

  9. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    International Nuclear Information System (INIS)

    Himanen, Sari J.; Nerg, Anne-Marja; Nissinen, Anne; Stewart, C. Neal; Poppy, Guy M.; Holopainen, Jarmo K.

    2009-01-01

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants

  10. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

    2009-01-15

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

  11. Strongly correlated perovskite fuel cells

    Science.gov (United States)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  12. CLOUDS IN SUPER-EARTH ATMOSPHERES: CHEMICAL EQUILIBRIUM CALCULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mbarek, Rostom; Kempton, Eliza M.-R., E-mail: mbarekro@grinnell.edu, E-mail: kemptone@grinnell.edu [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States)

    2016-08-20

    Recent studies have unequivocally proven the existence of clouds in super-Earth atmospheres. Here we provide a theoretical context for the formation of super-Earth clouds by determining which condensates are likely to form under the assumption of chemical equilibrium. We study super-Earth atmospheres of diverse bulk composition, which are assumed to form by outgassing from a solid core of chondritic material, following Schaefer and Fegley. The super-Earth atmospheres that we study arise from planetary cores made up of individual types of chondritic meteorites. They range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a range of atmospheric composition that is appropriate for low-mass exoplanets. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of formation for over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350–3000 K. Clouds should form along the temperature–pressure boundaries where the condensed species appear in our calculation. We find that the composition of condensate clouds depends strongly on both the H:O and C:O ratios. For the super-Earth archetype GJ 1214b, KCl and ZnS are the primary cloud-forming condensates at solar composition, in agreement with previous work. However, for oxidizing atmospheres, K{sub 2}SO{sub 4} and ZnO condensates are favored instead, and for carbon-rich atmospheres with super-solar C:O ratios, graphite clouds appear. For even hotter planets, clouds form from a wide variety of rock-forming and metallic species.

  13. Dissolution rates of unirradiated UO{sub 2}, UO{sub 2} doped with {sup 233}U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    Energy Technology Data Exchange (ETDEWEB)

    Ollila, Kaija [VTT Processes, Helsinki (Finland); Albinsson, Yngve [Chalmers Univ. of Technology, Goeteborg (Sweden); Oversby, Virginia [VMO Konsult, Stockholm (Sweden); Cowper, Mark [AEA Technology, Harwell (United Kingdom)

    2003-10-01

    The experimental results given in this report allow us to draw the following conclusions. 1) Tests using unirradiated fuel pellet materials from two different manufacturers gave very different dissolution rates under air atmosphere testing. Tests for fragments of pellets from different pellets made by the same manufacturer gave good agreement. This indicates that details of the manufacturing process have a large effect on the behavior of unirradiated UO{sub 2} in dissolution experiments. Care must be taken in interpreting differences in results obtained in different laboratories because the results may be affected by manufacturing effects. 2) Long-term tests under air atmosphere have begun to show the effects of precipitation. Further testing will be needed before the samples reach steady state. 3) Testing of unirradiated UO{sub 2} in systems containing an iron strip to produce reducing conditions gave [U] less than detection limits (<0.02 ppb) after a few days to a few weeks of testing. Uranium recovered from the rinsing of reaction vessels and from acid stripping of vessels was shown to be from dissolution of grains of solid dislodged when the samples were handled after the tests were terminated. 4) Batch tests conducted under reducing conditions showed evidence of colloidal material in the early solution samples. 5) In the batch tests, measurements taken at day 3 and day 5 show that precipitation occurs from day 3 to day 5 without any further dissolution of the solid. 6) At termination of the batch tests, all but one sample had [U] in solution less than detection limits (< 0.02 ppb). Materials recovered in test termination samples showed evidence for recovery of small amounts - amounts corresponding to that expected from a few grains of 5 to 10 {mu}m size - in the acidified solution samples. These are interpreted to have been dislodged during sample handling operations. 7) Batch test data show that increasing test duration beyond 2 weeks does not provide

  14. Contribution to the study of atmospheric projection and under partial vacuum of tungsten carbide particles with cobalt or nickel binder. Application to fretting coatings on steel

    International Nuclear Information System (INIS)

    Vinayo, Maria-Elena

    1985-01-01

    This research thesis addresses the plasma spraying (atmospheric, under controlled atmosphere, and under reduced pressure) of tungsten carbides with a metallic binder (WC/Co, WC/Ni; W 2 C/Co). This work comprised an optimisation of the spraying process under reduced pressure, the study of the influence of the powder production process on the physicochemical and micro-structural characteristics as well as on coating fretting properties, and a correlation between spraying parameters in a controlled atmosphere (power and pressure) and coating physico-chemical and micro-structural properties. Results show a high decarburization-oxidation of tungsten carbides during atmospheric spraying, as well as an important evaporation of cobalt. Under reduced pressure, high losses of carbides are noticed. These both phenomena strongly depend on the powder production process. Fretting results highlight remarkable performance of coatings obtained by atmospheric spraying [fr

  15. Evolution of Earth-like Extrasolar Planetary Atmospheres: Assessing the Atmospheres and Biospheres of Early Earth Analog Planets with a Coupled Atmosphere Biogeochemical Model.

    Science.gov (United States)

    Gebauer, S; Grenfell, J L; Stock, J W; Lehmann, R; Godolt, M; von Paris, P; Rauer, H

    2017-01-01

    Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models. In this work, we present results from our newly developed Coupled Atmosphere Biogeochemistry model in which atmospheric O 2 concentrations are fixed to values inferred by geological evidence. Applying a unique tool (Pathway Analysis Program), ours is the first quantitative analysis of catalytic cycles that governed O 2 in early Earth's atmosphere near the Great Oxidation Event. Complicated oxidation pathways play a key role in destroying O 2 , whereas in the upper atmosphere, most O 2 is formed abiotically via CO 2 photolysis. The O 2 bistability found by Goldblatt et al. ( 2006 ) is not observed in our calculations likely due to our detailed CH 4 oxidation scheme. We calculate increased CH 4 with increasing O 2 during the Great Oxidation Event. For a given atmospheric surface flux, different atmospheric states are possible; however, the net primary productivity of the biosphere that produces O 2 is unique. Mixing, CH 4 fluxes, ocean solubility, and mantle/crust properties strongly affect net primary productivity and surface O 2 fluxes. Regarding exoplanets, different "states" of O 2 could exist for similar biomass output. Strong geological activity could lead to false negatives for life (since our analysis suggests that reducing gases

  16. South African seasonal rainfall prediction performance by a coupled ocean-atmosphere model

    CSIR Research Space (South Africa)

    Landman, WA

    2010-12-01

    Full Text Available Evidence is presented that coupled ocean-atmosphere models can already outscore computationally less expensive atmospheric models. However, if the atmospheric models are forced with highly skillful SST predictions, they may still be a very strong...

  17. Strong imploding shock, the representative curve

    International Nuclear Information System (INIS)

    Mishkin, E.A.; Alejaldre, C.

    1981-01-01

    The representative curve of the ideal gas behind the front of a spherically, or cylindrically, symmetric strong imploding shock is shown to pass through the point where the reduced pressure is maximum, P(xisub(m)) = Psub(m)sub(a)sub(x). (orig.)

  18. Strong Coupling Corrections in Quantum Thermodynamics

    Science.gov (United States)

    Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

    2018-03-01

    Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

  19. Formation of a hybrid-type proto-atmosphere on Mars accreting in the solar nebula

    Science.gov (United States)

    Saito, Hiroaki; Kuramoto, Kiyoshi

    2018-03-01

    Recent studies of the chronology of Martian meteorites suggest that the growth of Mars was almost complete within a few Myr after the birth of the Solar system. During such rapid accretion, proto-Mars likely gravitationally maintained both the solar nebula component and the impact degassing component, containing H2O vapour and reduced gas species, as a proto-atmosphere to be called a hybrid-type proto-atmosphere. Here we numerically analyse the mass and composition of the degassed component and the atmospheric thermal structure sustained by accretional heating. Our results predict that a growing Mars possibly acquired a massive and hot hybrid-type proto-atmosphere with surface pressure and temperature greater than several kbar and 2000 K, respectively, which is sufficient to produce a deep magma ocean. In such a high-temperature and high-pressure environment, a significant amount of H2O, CH4, CO, and H2 is expected to be partitioned into the planetary interior, although this would strongly depend on the dynamics of the magma ocean and mantle solidification. The dissolved H2O may explain the wet Martian mantle implied from basaltic Martian meteorites. Along with the remnant reduced atmosphere after the hydrodynamic atmospheric escape, dissolved reduced gas species may have maintained an earliest Martian surface environment that allowed prebiotic chemical evolution and liquid H2O activities.

  20. Atmospheric chemistry and climate

    OpenAIRE

    Satheesh, SK

    2012-01-01

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

  1. New constraints on terrestrial and oceanic sources of atmospheric methanol

    Directory of Open Access Journals (Sweden)

    D. B. Millet

    2008-12-01

    Full Text Available We use a global 3-D chemical transport model (GEOS-Chem to interpret new aircraft, surface, and oceanic observations of methanol in terms of the constraints that they place on the atmospheric methanol budget. Recent measurements of methanol concentrations in the ocean mixed layer (OML imply that in situ biological production must be the main methanol source in the OML, dominating over uptake from the atmosphere. It follows that oceanic emission and uptake must be viewed as independent terms in the atmospheric methanol budget. We deduce that the marine biosphere is a large primary source (85 Tg a−1 of methanol to the atmosphere and is also a large sink (101 Tg a−1, comparable in magnitude to atmospheric oxidation by OH (88 Tg a−1. The resulting atmospheric lifetime of methanol in the model is 4.7 days. Aircraft measurements in the North American boundary layer imply that terrestrial plants are a much weaker source than presently thought, likely reflecting an overestimate of broadleaf tree emissions, and this is also generally consistent with surface measurements. We deduce a terrestrial plant source of 80 Tg a−1, comparable in magnitude to the ocean source. The aircraft measurements show a strong correlation with CO (R2=0.51−0.61 over North America during summer. We reproduce this correlation and slope in the model with the reduced plant source, which also confirms that the anthropogenic source of methanol must be small. Our reduced plant source also provides a better simulation of methanol observations over tropical South America.

  2. Review: the atmospheric boundary layer

    Science.gov (United States)

    Garratt, J. R.

    1994-10-01

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

  3. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  4. Instabilities in strongly coupled plasmas

    CERN Document Server

    Kalman, G J

    2003-01-01

    The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

  5. Promoting Strong Written Communication Skills

    Science.gov (United States)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  6. Short proofs of strong normalization

    OpenAIRE

    Wojdyga, Aleksander

    2008-01-01

    This paper presents simple, syntactic strong normalization proofs for the simply-typed lambda-calculus and the polymorphic lambda-calculus (system F) with the full set of logical connectives, and all the permutative reductions. The normalization proofs use translations of terms and types to systems, for which strong normalization property is known.

  7. High resolution transmission spectroscopy as a diagnostic for Jovian exoplanet atmospheres: constraints from theoretical models

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); Perna, Rosalba [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Heng, Kevin, E-mail: kemptone@grinnell.edu [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2014-11-01

    We present high resolution transmission spectra of giant planet atmospheres from a coupled three-dimensional (3D) atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model Jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9-55 day orbital periods around solar-type stars. The results of our 3D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple one-dimensional (1D) models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blueshifts of up to 3 km s{sup –1}, whereas less irradiated planets show almost no net Doppler shifts. We find only minor differences between transmission spectra for atmospheres with temperature inversions and those without. Compared to 1D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1D atmospheric models may be inadequate, as 3D atmospheric motions can produce a noticeable effect on the absorption

  8. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  9. Unintended consequences of atmospheric injection of sulphate aerosols.

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

    2010-10-01

    Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the

  10. Medicanes in an ocean-atmosphere coupled regional climate model

    Science.gov (United States)

    Akhtar, N.; Brauch, J.; Dobler, A.; Béranger, K.; Ahrens, B.

    2014-08-01

    So-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and warm-core Mediterranean cyclones that exhibit some similarities to tropical cyclones. The strong cyclonic winds associated with medicanes threaten the highly populated coastal areas around the Mediterranean basin. To reduce the risk of casualties and overall negative impacts, it is important to improve the understanding of medicanes with the use of numerical models. In this study, we employ an atmospheric limited-area model (COSMO-CLM) coupled with a one-dimensional ocean model (1-D NEMO-MED12) to simulate medicanes. The aim of this study is to assess the robustness of the coupled model in simulating these extreme events. For this purpose, 11 historical medicane events are simulated using the atmosphere-only model, COSMO-CLM, and coupled model, with different setups (horizontal atmospheric grid spacings of 0.44, 0.22, and 0.08°; with/without spectral nudging, and an ocean grid spacing of 1/12°). The results show that at high resolution, the coupled model is able to not only simulate most of medicane events but also improve the track length, core temperature, and wind speed of simulated medicanes compared to the atmosphere-only simulations. The results suggest that the coupled model is more proficient for systemic and detailed studies of historical medicane events, and that this model can be an effective tool for future projections.

  11. Ionization Efficiency in the Dayside Martian Upper Atmosphere

    Science.gov (United States)

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

    2018-04-01

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

  12. The Structure and Composition of Io's Atmosphere

    Science.gov (United States)

    Smyth, W. H.; Marconi, M. L.

    2011-12-01

    Io's atmosphere is thought to be generated principally by sublimation on the dayside and by multiple volcanoes scattered throughout its surface and more concentrated near the equator. While SO2 seems to be the principle product of these sources, many other chemical species are placed into the atmosphere by these sources, including substantial amounts of SO and S2 as well as smaller but observationally significant amounts of Na bearing molecules. These species in turn interact strongly with the torus plasma generating additional species such as O2, S, O, and Na. The strong interaction of the torus plasma with the neutral atmosphere not only exerts a profound effect on the composition of Io's atmosphere but also strongly affects the dynamics and thermodynamics of Io's atmosphere, particularly at higher altitudes. In addition, as Io orbits Jupiter, the change in location of the sublimation region and the eclipse of Io as it passes through Jupiter's shadow result in substantial variation in the atmosphere. A complex time-dependent three-dimensional atmosphere with strong spatial compositional variation is created. Here we extend the two-dimensional multispecies Navier-Stokes model of Smyth and Wong (2004) to three-dimensions, include two volcanic sources similar to Pele and Loki, and include the effect of Io's movement around Jupiter on sublimation. The effects of the torus plasma are also included as in Smyth and Wong. We will present the overall composition and structure of the atmosphere, O to S ratios in the upper atmosphere, and discuss a potential issue with the O2 abundance. Smyth, W.H. and M.C. Wong, Icarus 171, 171-182, 2004.

  13. Atmospheric Research 2014 Technical Highlights

    Science.gov (United States)

    Platnick, Steven

    2015-01-01

    Earth Sciences Division in atmospheric science research. Figure 1.1 shows the 20-year record of peer-reviewed publications and proposals among the various Laboratories. This data shows that the scientific work being conducted in the Laboratories is competitive with the work being done elsewhere in universities and other government agencies. The office of Deputy Director for Atmospheric Research will strive to maintain this record by rigorously monitoring and promoting quality while emphasizing coordination and integration among atmospheric disciplines. Also, an appropriate balance will be maintained between the scientists' responsibility for large collaborative projects and missions and their need to carry out active science research as a principal investigator. This balance allows members of the Laboratories to improve their scientific credentials, and develop leadership potentials. Interdisciplinary research is carried out in collaboration with other laboratories and research groups within the Earth Sciences Division, across the Sciences and Exploration Directorate, and with partners in universities and other government agencies. Members of the Laboratories interact with the general public to support a wide range of interests in the atmospheric sciences. Among other activities, the Laboratories raise the public's awareness of atmospheric science by presenting public lectures and demonstrations, by making scientific data available to wide audiences, by teaching, and by mentoring students and teachers. The Atmosphere Laboratories make substantial efforts to attract and recruit new scientists to the various areas of atmospheric research. We strongly encourage the establishment of partnerships with Federal and state agencies that have operational responsibilities to promote the societal application of our science products. This report describes our role in NASA's mission, provides highlights of our research scope and activities, and summarizes our scientists' major

  14. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  15. Strong interactions at high energy

    International Nuclear Information System (INIS)

    Anselmino, M.

    1995-01-01

    Spin effects in strong interaction high energy processes are subtle phenomena which involve both short and long distance physics and test perturbative and non perturbative aspects of QCD. Moreover, depending on quantities like interferences between different amplitudes and relative phases, spin observables always test a theory at a fundamental quantum mechanical level; it is then no surprise that spin data are often difficult to accommodate within the existing models. A report is made on the main issues and contributions discussed in the parallel Session on the open-quote open-quote Strong interactions at high energy close-quote close-quote in this Conference. copyright 1995 American Institute of Physics

  16. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  17. Sensitivity of marine protected area network connectivity to atmospheric variability.

    Science.gov (United States)

    Fox, Alan D; Henry, Lea-Anne; Corne, David W; Roberts, J Murray

    2016-11-01

    International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming cold-water corals in the northeast Atlantic to changes in larval dispersal driven by atmospheric cycles and larval behaviour. Trajectories of Lophelia pertusa larvae were strongly correlated to the North Atlantic Oscillation (NAO), the dominant pattern of interannual atmospheric circulation variability over the northeast Atlantic. Variability in trajectories significantly altered network connectivity and source-sink dynamics, with positive phase NAO conditions producing a well-connected but asymmetrical network connected from west to east. Negative phase NAO produced reduced connectivity, but notably some larvae tracked westward-flowing currents towards coral populations on the mid-Atlantic ridge. Graph theoretical metrics demonstrate critical roles played by seamounts and offshore banks in larval supply and maintaining connectivity across the network. Larval longevity and behaviour mediated dispersal and connectivity, with shorter lived and passive larvae associated with reduced connectivity. We conclude that the existing MPA network is vulnerable to atmospheric-driven changes in ocean circulation.

  18. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...... of a discrete random variable....

  19. Strong coupling electroweak symmetry breaking

    International Nuclear Information System (INIS)

    Barklow, T.L.; Burdman, G.; Chivukula, R.S.

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models

  20. Strong coupling electroweak symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Barklow, T.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Burdman, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Chivukula, R.S. [Boston Univ., MA (United States). Dept. of Physics

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models.

  1. The colours of strong interaction

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)

  2. Strong cosmic censorship and the strong curvature singularities

    International Nuclear Information System (INIS)

    Krolak, A.

    1987-01-01

    Conditions are given under which any asymptotically simple and empty space-time that has a partial Cauchy surface with an asymptotically simple past is globally hyperbolic. It is shown that this result suggests that the Cauchy horizons of the type occurring in Reissner--Nordstroem and Kerr space-times are unstable. This in turn gives support for the validity of the strong cosmic censorship hypothesis

  3. 13. Atmosphere and climate

    International Nuclear Information System (INIS)

    Mock, G.; Hammond, A.

    1992-01-01

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

  4. Investigation of Titan's surface and atmosphere photometric functions using the Cassini/VIMS instrument

    Science.gov (United States)

    Cornet, Thomas; Altobelli, Nicolas; Rodriguez, Sébastien; Maltagliati, Luca; Le Mouélic, Stéphane; Sotin, Christophe; Brown, Robert; Barnes, Jason; Buratti, Bonnie; Baines, Kevin; Clark, Roger; Nicholson, Phillip

    2015-04-01

    After 106 flybys spread over 10 years, the Cassini Visual and Infrared Mapping Spectrometer (VIMS) instrument acquired 33151 hyperspectral cubes pointing at the surface of Titan on the dayside. Despite this huge amount of data available for surface studies, and due to the strong influence of the atmosphere (methane absorption and haze scattering), Titan's surface is only visible with VIMS in 7 spectral atmospheric windows centred at 0.93, 1.08, 1.27, 1.59, 2.01, 2.7-2.8 and 5 microns. Atmospheric scattering and absorption effects dominate Titan's spectrum at wavelengths shorter than 3 microns, while the 5 micron window, almost insensitive to the haze scattering, only presents a reduced atmospheric absorption contribution to the signal recorded by VIMS. In all cases, the recorded I/F represents an apparent albedo, which depends on the atmospheric contributions and the surface photometry at each wavelength. We therefore aim to determine real albedo values for Titan's surface by finding photometric functions for the surface and the atmosphere that could be used as a basis for empirical corrections or Radiative Transfer calculations. After updating the navigation of the VIMS archive, we decomposed the entire VIMS data set into a MySQL relational database gathering the viewing geometry, location, time (season) and I/F (for pure atmosphere and surface-atmosphere images) for each pixel of the 33151 individual VIMS cubes. We then isolated all the VIMS pixels where Titan's surface has been repeatedly imaged at low phase angles (< 20 degrees) in order to characterize phase curves for the surface at 5 microns and for the atmosphere. Among these, the T88 flyby appears noteworthy, with a "Emergence-Phase Function (EPF)"-type observation: 25 cubes acquired during the same flyby, over the same area (close to Tortola Facula, in relatively dark terrains), at a constant incidence and with varying emergence and phase (from 0 to 60 degrees) angles. The data clearly exhibit an increase

  5. Quantum strongly secure ramp secret sharing

    DEFF Research Database (Denmark)

    Zhang, Paul; Matsumoto, Rytaro Yamashita

    2015-01-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together...... however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced....... This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can...

  6. Quantum Transport in Strongly Correlated Systems

    DEFF Research Database (Denmark)

    Bohr, Dan

    2007-01-01

    the density matrix renormalization group (DMRG) method. We present two DMRG setups for calculating the linear conductance of strongly correlated nanostructures in the infinitesimal source-drain voltage regime. The first setup describes the leads by modified real-space tight-binding chains, whereas the second....... Thus both coherence and correlation effects are important in this model, and the methods applied should be able to handle both these effects rigorously. We present the DMRG setup for this model and benchmark against existing Greens function results for the model. Then we present initial DMRG results...... screening plays a much less significant role than in bulk systems due to the reduced size of the objects, therefore making it necessary to consider the importance of correlations between electrons. The work presented in this thesis deals with quantum transport through strongly correlated systems using...

  7. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  8. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  9. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  10. Recovering of images degraded by atmosphere

    Science.gov (United States)

    Lin, Guang; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

    2017-08-01

    Remote sensing images are seriously degraded by multiple scattering and bad weather. Through the analysis of the radiative transfer procedure in atmosphere, an image atmospheric degradation model considering the influence of atmospheric absorption multiple scattering and non-uniform distribution is proposed in this paper. Based on the proposed model, a novel recovering method is presented to eliminate atmospheric degradation. Mean-shift image segmentation and block-wise deconvolution are used to reduce time cost, retaining a good result. The recovering results indicate that the proposed method can significantly remove atmospheric degradation and effectively improve contrast compared with other removal methods. The results also illustrate that our method is suitable for various degraded remote sensing, including images with large field of view (FOV), images taken in side-glance situations, image degraded by atmospheric non-uniform distribution and images with various forms of clouds.

  11. Designing Affective Atmospheres on the Move

    DEFF Research Database (Denmark)

    Wind, Simon; Lanng, Ditte Bendix

    travelling “unfolds affects as much as reasons” (Jensen, 2013, p.99). Practices, embodiment, technologies and materialities interconnect in non-quantifiable experiences of mobilities, which may fruitfully be unfolded by means of the concept of “atmosphere”. According to Böhme, atmosphere cannot be reduced...... to properties or qualities of neither human nor non-human bodies but they are “manifestations of the co-presence of subject and object” (Böhme, 1998, p.114). When travelling in and through spaces of mobilities in everyday life we are co-constituents in an on-flow of aesthetic atmospheres shaping emotional...... an analytical tool for capturing atmospheres as well as an interventionist tool for orchestrating atmospheres in everyday urban spaces of mobilities. References Anderson, B. (2009) ´Affective Atmospheres´, in: Emotion, Space and Society, pp. 77–81 Bissel, D. (2010) ´Passenger mobilities: affective atmospheres...

  12. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  13. String dynamics at strong coupling

    International Nuclear Information System (INIS)

    Hull, C.M.

    1996-01-01

    The dynamics of superstring, supergravity and M-theories and their compactifications are probed by studying the various perturbation theories that emerge in the strong and weak-coupling limits for various directions in coupling constant space. The results support the picture of an underlying non-perturbative theory that, when expanded perturbatively in different coupling constants, gives different perturbation theories, which can be perturbative superstring theories or superparticle theories. The p-brane spectrum is considered in detail and a criterion found to establish which p-branes govern the strong-coupling dynamics. In many cases there are competing conjectures in the literature, and this analysis decides between them. In other cases, new results are found. The chiral 6-dimensional theory resulting from compactifying the type IIB string on K 3 is studied in detail and it is found that certain strong-coupling limits appear to give new theories, some of which hint at the possibility of a 12-dimensional origin. (orig.)

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

    Science.gov (United States)

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

    2016-01-01

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

  15. On the CO2 exchange between the atmosphere and the biosphere: the role of synoptic and mesoscale processes

    International Nuclear Information System (INIS)

    Chan, Douglas; Higuchi, Kaz; Shashkov, Alexander; Worthy, Douglas; Liu, Jane; Chen Jing; Yuen Chiu Wai

    2004-01-01

    Estimating global carbon fluxes by inverting atmospheric CO 2 through the use of atmospheric transport models has shown the importance of the covariance between biospheric fluxes and atmospheric transport on the carbon budget. This covariance or coupling occurs on many time scales. This study examines the coupling of the biosphere and the atmosphere on the meso- and synoptic scales using a coupled atmosphere-biosphere regional model covering Canada. The results are compared with surface and light aircraft measurement campaigns at two boreal forest sites in Canada. Associated with cold and warm frontal features, the model results showed that the biospheric fluxes are strongly coupled to the atmosphere through radiative forcing. The presence of cloud near frontal regions usually results in reduced photosynthetic uptake, producing CO 2 concentration gradients across the frontal regions on the order of 10 parts per million (ppm). Away from the frontal region, the biosphere is coupled to the mesoscale variations in similar ways, resulting in mesoscale variations in CO 2 concentrations of about 5 ppm. The CO 2 field is also coupled strongly to the atmospheric dynamics. In the presence of frontal circulation, the CO 2 near the surface can be transported to the mid to upper troposphere. Mesoscale circulation also plays a significant part in transporting the CO 2 from the planetary boundary layer (PBL) to the mid-troposphere. In the absence of significant mesoscale or synoptic scale circulation, the CO 2 in the PBL has minimal exchange with the free troposphere, leading to strong gradients across the top of the PBL. We speculate that the ubiquity of the common synoptic and mesoscale processes in the atmosphere may contribute significantly to the rectifier effect and hence CO 2 inversion calculations

  16. Helium atoms and molecules in strong magnetic fields

    Science.gov (United States)

    Mori, K.

    Recent theoretical studies have shown that the neutron star surface may be composed of helium or heavier elements as hydrogen may be quickly depleted by diffuse nuclear burning Chang Bildsten However while Hydrogen atmospheres have been studied in great details atomic data for helium is available only for He ion Pavlov Bezchastnov 2005 We performed Hartree-Fock type calculation for Helium atom and molecules and computed their binding ionization and dissociation energies in strong magnetic fields B sim10 12 -- 10 15 G We will present ionization balance of Helium atmospheres at typical magnetic field strengths and temperatures to radio-quiet neutron stars and AXPs We will also discuss several implications of helium atmosphere to X-ray data of isolated neutron stars focusing on the detected spectral features

  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. A class of solutions for the strong gravity equations

    International Nuclear Information System (INIS)

    Salam, A.; Strathdee, J.

    1976-12-01

    We solve the Einstein equation for strong gravity in the limit that weak gravity is neglected. The class of solutions we find reduces to the Schwarzschild solution (with the weak gravity Newtonian constant replaced by a strong coupling parameter) in the limit M 2 →0 where M is the mass of the strong gravity spin-2 meson. These solutions may be of relevance for the problem of defining temperature in hadronic physics

  19. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  20. Strong enhancement of transport by interaction on contact links

    DEFF Research Database (Denmark)

    Bohr, Dan; Schmitteckert, P.

    2007-01-01

    Strong repulsive interactions within a one-dimensional Fermi system in a two-probe configuration normally lead to a reduced off-resonance conductance. We show that if the repulsive interaction extends to the contact regions, a strong increase of the conductance may occur, even for systems where o...

  1. Matter and Radiation in Strong Magnetic Fields of Neutron Stars

    International Nuclear Information System (INIS)

    Lai, D

    2006-01-01

    Neutron stars are found to possess magnetic fields ranging from 10 8 G to 10 15 G, much larger than achievable in terrestrial laboratories. Understanding the properties of matter and radiative transfer in strong magnetic fields is essential for the proper interpretation of various observations of magnetic neutron stars, including radio pulsars and magnetars. This paper reviews the atomic/molecular physics and condensed matter physics in strong magnetic fields, as well as recent works on modeling radiation from magnetized neutron star atmospheres/surface layers

  2. Feasibility study of cocos, condensation of containment atmosphere on structures

    International Nuclear Information System (INIS)

    Rij, H.M. van; Vonka, V.

    1989-12-01

    The aim of this report is to assess the state of the art of the knowledge of the thermo-hydraulic conditions within a LWR containment in order to determine both the radioactive and the non-radioactive aerosol deposition rates during a severe reactor accident. The radioactive aerosol in the containment atmosphere is, together with the noble gases, responsible for the radioactive source term into the biosphere when a containment failure occurs. The dominant aerosol removal mechanisms depend strongly upon the thermal-hydraulic state of the containment atmosphere. It is demonstrated that the thermohydraulic state, determined by heat sources and the sensible heat transport, is predominantly super-heated when fission products are released into the containment. Hence the thermohydraulic conditions are not favorable for an intensive bulk condensation onto aerosol particles during an essential period of time. A station black-out scenario, in which the primary system of the considered 500 MWe PWR with a dry cavity is depressurized prior to vessel failure, is used as an example to demonstrate this effect. The results, obtained with the CONTAIN code, show the relevance of the sensible heat transport in the period of time (c.a. 30 minutes) between the end of the injection of the steam and fission products into the containment, and the molten core concrete interaction. All considered variation of the station black-out scenario, in which the decay heat dissipated in the containment atmosphere has been 10% of the total decay heat, indicate that the atmosphere becomes super-heated within the 30 minutes. Reducing the fraction of the decay heat in the containment from the 10% to 5% increases the time period with saturated conditions. The amount of the decay heat released into the containment atmosphere forms the major factor determining the thermohydraulic state. It influences the duration of the bulk condensation period, which in turn has an influence on the aerosol deposition

  3. Atmospheric refraction : a history

    NARCIS (Netherlands)

    Lehn, WH; van der Werf, S

    2005-01-01

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

  4. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  5. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  6. Strong versions of Bell's theorem

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1994-01-01

    Technical aspects of a recently constructed strong version of Bell's theorem are discussed. The theorem assumes neither hidden variables nor factorization, and neither determinism nor counterfactual definiteness. It deals directly with logical connections. Hence its relationship with modal logic needs to be described. It is shown that the proof can be embedded in an orthodox modal logic, and hence its compatibility with modal logic assured, but that this embedding weakens the theorem by introducing as added assumptions the conventionalities of the particular modal logic that is adopted. This weakening is avoided in the recent proof by using directly the set-theoretic conditions entailed by the locality assumption

  7. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  8. Weak consistency and strong paraconsistency

    Directory of Open Access Journals (Sweden)

    Gemma Robles

    2009-11-01

    Full Text Available In a standard sense, consistency and paraconsistency are understood as, respectively, the absence of any contradiction and as the absence of the ECQ (“E contradictione quodlibet” rule that allows us to conclude any well formed formula from any contradiction. The aim of this paper is to explain the concepts of weak consistency alternative to the standard one, the concepts of paraconsistency related to them and the concept of strong paraconsistency, all of which have been defined by the author together with José M. Méndez.

  9. On the strong CP problem

    Energy Technology Data Exchange (ETDEWEB)

    Dowrick, N.J. (Dept. of Physics, Oxford (United Kingdom)); McDougall, N.A. (National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan))

    1992-07-09

    We show that two well-known solutions to the strong CP problem, the axion and a massless quark, may be understood in terms of the mechanism recently proposed by Samuel where long-range interactions between topological charges may be responsible for the removal of CP violation. We explain how the axion and a QCD meson (identified as the {eta}' if all quarks are massless) suppress fluctuations in global topological charge by almost identical dynamical although the masses, couplings and relevant length scales are very different. Furthermore, we elucidate the precise origin of the {eta}' mass. (orig.).

  10. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  11. Estimation of strong ground motion

    International Nuclear Information System (INIS)

    Watabe, Makoto

    1993-01-01

    Fault model has been developed to estimate a strong ground motion in consideration of characteristics of seismic source and propagation path of seismic waves. There are two different approaches in the model. The first one is a theoretical approach, while the second approach is a semi-empirical approach. Though the latter is more practical than the former to be applied to the estimation of input motions, it needs at least the small-event records, the value of the seismic moment of the small event and the fault model of the large event

  12. Strong Mechanoluminescence from Oxynitridosilicate Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lin; Xu Chaonan; Yamada, Hiroshi, E-mail: cn-xu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku, Tosu, Saga 841-0052 (Japan)

    2011-10-29

    We successfully developed a novel Mechanoluminescence (ML) material with water resistance, oxynitridosilicate; BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+}. The crystal structure, photoluminescence (PL) and ML properties were characterized. The ML of BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+} is so strong that the blue-green emission can be observed by the naked eyes clearly. In addition, it shows superior water resistance property. No changes were found in the ML intensities during the total water treatment test.

  13. Effective lagrangian for strong interactions

    International Nuclear Information System (INIS)

    Jain, P.

    1988-01-01

    We attempt to construct a realistic phenomenological Lagrangian in order to describe strong interactions. This is in general a very complicated problem and we shall explore its various aspects. We first include the vector mesons by writing down the most general chiral invariant terms proportional to the Levi-Civita symbol ε μναβ . These terms involve three unknown coefficients, which are calculated by using the experimental results of strong interaction processes. We then calculate the static nucleon properties by finding the solitonic excitations of this model. The results turn out to be, as is also the case for most other vector-pseudoscalar Lagrangians, better than the Skyrme model but are still somewhat different from the experiments. Another aspect that we shall study is the incorporation of scale anomaly of QCD into the Skyrme model. We thus introduce a scalar glueball in our Lagrangian. Here we find an interesting result that the effective glue field dynamically forms a bag for the soliton. Depending on the values of the parameters, we get either a deep bag or a shallow bag. However by including the scalar meson, we find that to get realistic scalar sector we must have the shallow bag. Finally we show some intriguing connections between the chiral quark model, in which the nucleon is described as a solitonic excitation, and the ordinary potential binding quark model

  14. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  15. Strong Selective Adsorption of Polymers.

    Science.gov (United States)

    Ge, Ting; Rubinstein, Michael

    2015-06-09

    A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the

  16. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-20

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

  17. 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.

  18. Evaluation of methods to reduce or compensate for the effects of increased levels of atmospheric CO/sub 2/. Bewertung von Massnahmen zur Reduzierung bzw. Kompensation der Answirkung von CO/sub 2/ - Anreicherungen in der Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Bach, W; Jung, H J

    1980-07-01

    After a short introduction to the carbon dioxide issue carbon dioxide disposal methods are evaluated. Studies of the prognosis for energy conservation are reviewed and the possibility of reducing the consumption of fossil fuels discussed. Methods of compensating for a carbon dioxide warming by modifying the earth's albedo are examined with particular attention to the consequences of this countermeasure for the radiative heat balance and the climate. (In German)

  19. Strong growth for Queensland mining

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    The Queensland mining industry experienced strong growth during 1989-90 as shown in the latest statistics released by the Department of Resource Industries. The total value of Queensland mineral and energy production rose to a new record of $5.1 billion, an increase of 16.5% on 1988-89 production. A major contributing factor was a 20.9 percent increase in the value of coal production. While the quantity of coal produced rose only 1.1 percent, the substantial increase in the value of coal production is attributable to higher coal prices negotiated for export contracts. In Australian dollar terms coal, gold, lead, zinc and crude oil on average experienced higher international prices than in the previous year. Only copper and silver prices declined. 3 tabs.

  20. Strong moduli stabilization and phenomenology

    CERN Document Server

    Dudas, Emilian; Mambrini, Yann; Mustafayev, Azar; Olive, Keith A

    2013-01-01

    We describe the resulting phenomenology of string theory/supergravity models with strong moduli stabilization. The KL model with F-term uplifting, is one such example. Models of this type predict universal scalar masses equal to the gravitino mass. In contrast, A-terms receive highly suppressed gravity mediated contributions. Under certain conditions, the same conclusion is valid for gaugino masses, which like A-terms, are then determined by anomalies. In such models, we are forced to relatively large gravitino masses (30-1000 TeV). We compute the low energy spectrum as a function of m_{3/2}. We see that the Higgs masses naturally takes values between 125-130 GeV. The lower limit is obtained from the requirement of chargino masses greater than 104 GeV, while the upper limit is determined by the relic density of dark matter (wino-like).

  1. Strongly interacting W's and Z's

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1984-01-01

    The study focussed primarily on the dynamics of a strongly interacting W, Z(SIW) sector, with the aim of sharpening predictions for total W, Z yield and W, Z multiplicities expected from WW fusion for various scenarios. Specific issues raised in the context of the general problem of modeling SIW included the specificity of the technicolor (or, equivalently, QCD) model, whether or not a composite scalar model can be evaded, and whether the standard model necessarily implies an I = J = O state (≅ Higgs particle) that is relatively ''light'' (M ≤ hundreds of TeV). The consensus on the last issue was that existing arguments are inconclusive. While the author shall briefly address compositeness and alternatives to the technicolor model, quantitative estimates will be of necessity based on technicolor or an extrapolation of pion data

  2. Uniquely Strongly Clean Group Rings

    Institute of Scientific and Technical Information of China (English)

    WANG XIU-LAN

    2012-01-01

    A ring R is called clean if every element is the sum of an idempotent and a unit,and R is called uniquely strongly clean (USC for short) if every element is uniquely the sum of an idempotent and a unit that commute.In this article,some conditions on a ring R and a group G such that RG is clean are given.It is also shown that if G is a locally finite group,then the group ring RG is USC if and only if R is USC,and G is a 2-group.The left uniquely exchange group ring,as a middle ring of the uniquely clean ring and the USC ring,does not possess this property,and so does the uniquely exchange group ring.

  3. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  4. Atmosphere after a nuclear war: twilight at noon

    Energy Technology Data Exchange (ETDEWEB)

    Crutzen, P; Birks, J

    1982-01-01

    If a nuclear war occurs, serious atmospheric consequences will result from the production of large amounts of particulate matter due to the many fires that will start in cities, industry, and particularly in forests, agricultural fields, and oil and gas fields. The authors estimate that for most of the Northern Hemisphere the average intensity of sunlight reaching the surface of the earth would be reduced by a large factor as a result of light absorption by particles in the submicron diameter size range, and this darkness would persist for as long as the fires burn, which is expected to be many weeks. The screening of sunlight by the fire-produced aerosol over extended periods during the growing season would eliminate much of the food production in the Northern Hemisphere. Marine ecosystems may be particularly sensitive to the loss of sunlight that would result. The fires would also inject large quantities of oxides of nitrogen and reactive hydrocarbons into the atmosphere, creating the potential for a severe photochemical smog situation throughout much of the Northern Hemisphere. The production of strong oxidants such as ozone and peroxyacetylnitrate (PAN) as the aerosol is removed from the atmosphere would also negatively influence food production throughout the Northern Hemisphere during the first year following the war.

  5. Study on IR Properties of Reduced Graphene Oxide

    Science.gov (United States)

    Ma, Deyue; Li, Xiaoxia; Guo, Yuxiang; Zeng, Yurun

    2018-01-01

    Firstly, the reduced graphene oxide was prepared by modified hummer method and characterized. Then, the complex refractive index of reduced graphene oxide in IR band was tested and its IR absorption and radiation properties were researched by correlated calculation. The results show that reduced graphene oxide prepared by hummer method are multilayered graphene with defects and functional groups on its surface. Its absorption in near and far IR bands is strong, but it’s weaker in middle IR band. At the IR atmosphere Window, its normal spectral emissivity decreases with wavelength increasing, and its total normal spectral emissivity in 3 ∼ 5μm and 8 ∼ 14μm are 0.75 and 0.625, respectively. Therefore, reduced graphene oxide can be used as IR absorption and coating materials and have a great potential in microwave and infrared compatible materials.

  6. Origin of the atmospheres of the earth and the planets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z M

    1978-06-01

    From a systematic analysis of the whole history of the protoplanetary cloud and the observational facts of the earth's atmosphere, new theory is proposed on the origin of the atmospheres of the earth and the planets. For the earth-like planets, there were profound primordial atmospheres originated from the protoplanetary cloud by the accretion of the embryoes of planets. These primordial atmospheres has existed in a time scale of 10/sup 3/ to 10/sup 7/ years and were composed of chemically reducing gases. The presence of such a reducing atmosphere may be of great significance to the theories of cosmogony and the origin of life. The contents are as follows: the escape of the nebulae and the planetary atmospheres, the blowing-off of the atmospheres and the disspiation of gases driven by the solar wind, the accretion of gases by the planetary embryoes, the primordial atmospheres.

  7. Jets in Planetary Atmospheres

    Science.gov (United States)

    Dowling, Tim

    2018-05-01

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

  8. Geophysical and atmospheric evolution of habitable planets.

    Science.gov (United States)

    Lammer, Helmut; Selsis, Frank; Chassefière, Eric; Breuer, Doris; Griessmeier, Jean-Mathias; Kulikov, Yuri N; Erkaev, Nikolai V; Khodachenko, Maxim L; Biernat, Helfried K; Leblanc, Francois; Kallio, Esa; Lundin, Richard; Westall, Frances; Bauer, Siegfried J; Beichman, Charles; Danchi, William; Eiroa, Carlos; Fridlund, Malcolm; Gröller, Hannes; Hanslmeier, Arnold; Hausleitner, Walter; Henning, Thomas; Herbst, Tom; Kaltenegger, Lisa; Léger, Alain; Leitzinger, Martin; Lichtenegger, Herbert I M; Liseau, René; Lunine, Jonathan; Motschmann, Uwe; Odert, Petra; Paresce, Francesco; Parnell, John; Penny, Alan; Quirrenbach, Andreas; Rauer, Heike; Röttgering, Huub; Schneider, Jean; Spohn, Tilman; Stadelmann, Anja; Stangl, Günter; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

    2010-01-01

    The evolution of Earth-like habitable planets is a complex process that depends on the geodynamical and geophysical environments. In particular, it is necessary that plate tectonics remain active over billions of years. These geophysically active environments are strongly coupled to a planet's host star parameters, such as mass, luminosity and activity, orbit location of the habitable zone, and the planet's initial water inventory. Depending on the host star's radiation and particle flux evolution, the composition in the thermosphere, and the availability of an active magnetic dynamo, the atmospheres of Earth-like planets within their habitable zones are differently affected due to thermal and nonthermal escape processes. For some planets, strong atmospheric escape could even effect the stability of the atmosphere.

  9. Strong interactions in low dimensions

    CERN Document Server

    Baeriswyl, D

    2007-01-01

    This book provides an attempt to convey the colorful facets of condensed matter systems with reduced dimensionality. Some of the specific features predicted for interacting one-dimensional electron systems, such as charge- and spin-density waves, have been observed in many quasi-one-dimensional materials. The two-dimensional world is even richer: besides d-wave superconductivity and the Quantum Hall Effect - perhaps the most spectacular phases explored during the last two decades - many collective charge and spin states have captured the interest of researchers, such as charge stripes or spont

  10. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  11. Strong Statistical Convergence in Probabilistic Metric Spaces

    OpenAIRE

    Şençimen, Celaleddin; Pehlivan, Serpil

    2008-01-01

    In this article, we introduce the concepts of strongly statistically convergent sequence and strong statistically Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong statistical limit points and the strong statistical cluster points of a sequence in this space and investigate the relations between these concepts.

  12. John Strong - 1941-2006

    CERN Multimedia

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  13. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  14. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.

    1988-10-01

    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  15. Fair weather atmospheric electricity

    International Nuclear Information System (INIS)

    Harrison, R G

    2011-01-01

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

  16. Atmosphere physics and chemistry

    International Nuclear Information System (INIS)

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

    2005-10-01

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

  17. Phytoremediation of Atmospheric Methane

    Science.gov (United States)

    2013-04-15

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

  18. Oscillations in stellar atmospheres

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  19. Reducing greenhouses and the temperature history of Earth and Mars

    International Nuclear Information System (INIS)

    Sagan, C.

    1977-01-01

    The modern theory of stellar evolution implies that the Sun has increased in brightness by several tens per cent over geological time. Were all other global parameters held constant, this would imply that the mean temperature of the Earth was below the freezing point of seawater about 2 x 10 9 yr ago. There is, however, excellent geological and palaeontological evidence that there were extensive bodies of liquid water on the Earth between 3 and 4 x 10 9 yr ago. A possible solution to this puzzle is that the Earth's primitive atmosphere contained small quantities of NH 3 and other reducing gases which significantly enhanced the global 'greenhouse' effect. Cosmochemical considerations point strongly to a higher abundance of reduced constituents in the primitive than in the contemporary terrestrial atmosphere; and reduced atmospheric components such as NH 3 and CH 4 are required to understand the accumulation of prebiological organic compounds necessary for the origin of life between 3 and 4 x 10 9 yr ago. Similar arguments may apply to Mars. (author)

  20. Reducing greenhouses and the temperature history of Earth and Mars

    Energy Technology Data Exchange (ETDEWEB)

    Sagan, C [Cornell Univ., Ithaca, N.Y. (USA). Lab. for Planetary Studies

    1977-09-15

    The modern theory of stellar evolution implies that the Sun has increased in brightness by several tens per cent over geological time. Were all other global parameters held constant, this would imply that the mean temperature of the Earth was below the freezing point of seawater about 2 x 10/sup 9/ yr ago. There is, however, excellent geological and palaeontological evidence that there were extensive bodies of liquid water on the Earth between 3 and 4 x 10/sup 9/ yr ago. A possible solution to this puzzle is that the Earth's primitive atmosphere contained small quantities of NH/sub 3/ and other reducing gases which significantly enhanced the global 'greenhouse' effect. Cosmochemical considerations point strongly to a higher abundance of reduced constituents in the primitive than in the contemporary terrestrial atmosphere; and reduced atmospheric components such as NH/sub 3/ and CH/sub 4/ are required to understand the accumulation of prebiological organic compounds necessary for the origin of life between 3 and 4 x 10/sup 9/ yr ago. Similar arguments may apply to Mars.

  1. Nucleation in the atmosphere

    International Nuclear Information System (INIS)

    Hegg, D A; Baker, M B

    2009-01-01

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

  2. 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...

  3. Strongly interacting photons and atoms

    International Nuclear Information System (INIS)

    Alge, W.

    1999-05-01

    This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)

  4. Topics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Skoric, M.M.

    1981-01-01

    This thesis discusses certain aspects of the turbulence of a fully ionised non-isothermal plasma dominated by the Langmuir mode. Some of the basic properties of strongly turbulent plasmas are reviewed. In particular, interest is focused on the state of Langmuir turbulence, that is the turbulence of a simple externally unmagnetized plasma. The problem of the existence and dynamics of Langmuir collapse is discussed, often met as a non-linear stage of the modulational instability in the framework of the Zakharov equations (i.e. simple time-averaged dynamical equations). Possible macroscopic consequences of such dynamical turbulent models are investigated. In order to study highly non-linear collapse dynamics in its advanced stage, a set of generalized Zakharov equations are derived. Going beyond the original approximation, the author includes the effects of higher electron non-linearities and a breakdown of slow-timescale quasi-neutrality. He investigates how these corrections may influence the collapse stabilisation. Recently, it has been realised that the modulational instability in a Langmuir plasma will be accompanied by the collisionless-generation of a slow-timescale magnetic field. Accordingly, a novel physical situation has emerged which is investigated in detail. The stability of monochromatic Langmuir waves in a self-magnetized Langmuir plasma, is discussed, and the existence of a novel magneto-modulational instability shown. The wave collapse dynamics is investigated and a physical interpretation of the basic results is given. A problem of the transient analysis of an interaction of time-dependent electromagnetic pulses with linear cold plasma media is investigated. (Auth.)

  5. An atmospheric electrical method to determine the eddy diffusion ...

    Indian Academy of Sciences (India)

    Keywords. Atmospheric electrical profiles; electrode layer; ion–aerosol balance equations. ... eddy diffusion theory (K-theory) in our model equations. K-theory is appropriate for near neutral ...... limit of strong turbulent mixing; J. Geophys. Res.

  6. Large-Scale Atmosphere-Ocean Coupling.

    Science.gov (United States)

    1984-05-01

    atmosphere (INT. -r, i 0) InEkman layer off the coast of Peru eastward) and meridional (y, positive north- the latter case. T, which was assumcd uniform...influence of teleconnectivity of the atmosphere is strongest for diabetic forcing located near the equatorial central Pacific, but much reduced i for ocinp...the monsoon diabetic heat sources during the latter half of the year (July- February, denoted by atching numerals). The extent of the diabetic beat

  7. Effect of Atmospheric Conditions on LIBS Spectra

    OpenAIRE

    Effenberger, Andrew J.; Scott, Jill R.

    2010-01-01

    Laser-induced breakdown spectroscopy (LIBS) is typically performed at ambient Earth atmospheric conditions. However, interest in LIBS in other atmospheric conditions has increased in recent years, especially for use in space exploration (e.g., Mars and Lunar) or to improve resolution for isotopic signatures. This review focuses on what has been reported about the performance of LIBS in reduced pressure environments as well as in various gases other than air.

  8. Effect of Atmospheric Conditions on LIBS Spectra

    Science.gov (United States)

    Effenberger, Andrew J.; Scott, Jill R.

    2010-01-01

    Laser-induced breakdown spectroscopy (LIBS) is typically performed at ambient Earth atmospheric conditions. However, interest in LIBS in other atmospheric conditions has increased in recent years, especially for use in space exploration (e.g., Mars and Lunar) or to improve resolution for isotopic signatures. This review focuses on what has been reported about the performance of LIBS in reduced pressure environments as well as in various gases other than air. PMID:22399914

  9. Impact Delivery of Reduced Greenhouse Gases on Early Mars

    Science.gov (United States)

    Haberle, R. M.; Zahnle, K. J.; Barlow, N. G.

    2017-12-01

    Reducing greenhouse gases are the latest trend in finding solutions to the early Mars climate dilemma. In thick CO2 atmospheres with modest concentrations of H2 and/or CH4, collision induced absorptions can reduce the outgoing long wave radiation enough to provide a significant greenhouse effect. To raise surface temperatures significantly by this process, surface pressures must be at least 500 mb and H2 and/or CH4 concentrations must be at or above the several percent level. Volcanism, serpentinization, and impacts are possible sources for reduced gases. Here we investigate the delivery of such gases by impact degassing from comets and asteroids. We use a time-marching stochastic impactor model that reproduces the observed crater size frequency distribution of Noachian surfaces. Following each impact, reduced gases are added to the atmosphere from a production function based on gas equilibrium calculations for several classes of meteorites and comets at typical post-impact temperatures. Escape and photochemistry then remove the reduced greenhouse gases continuously in time throughout each simulation. We then conduct an ensemble of simulations with this simple model varying the surface pressure, impact history, reduced gas production and escape functions, and mix of impactor types, to determine if this could be a potentially important part of the early Mars story. Our goal is to determine the duration of impact events that elevate reduced gas concentrations to significant levels and the total time of such events throughout the Noachian. Our initial simulations indicate that large impactors can raise H2 concentrations above the 10% level - a level high enough for a very strong greenhouse effect in a 1 bar CO2 atmosphere - for millions of years, and that the total time spent at or above that level can be in the 10's of millions of years range. These are interesting results that we plan to explore more thoroughly for the meeting.

  10. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning......Deformation twinning1, 2, 3, 4, 5, 6 in crystals is a highly coherent inelastic shearing process that controls the mechanical behaviour of many materials, but its origin and spatio-temporal features are shrouded in mystery. Using micro-compression and in situ nano-compression experiments, here we...... find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...

  11. Titan Coupled Surface/Atmosphere Retrievals

    Science.gov (United States)

    West, R. A.; Pitman, K. M.

    2009-05-01

    Titan's thick haze obscures its surface at visible wavelengths and hinders surface photometric studies in the near-infrared. The large vertical extent of the haze produces two effects which require radiative transfer analysis beyond the capability of plane-parallel multi-scatter models. Haze aerosols extend to altitudes above 500 km and require a spherical-shell RT algorithm close to the limb or terminator. Even near nadir viewing, horizontal scattering at spatial scales less than a few hundred km requires a code capable of simulating the adjacency effect. The adjacency effect will reduce contrast more for small spatial scales than for large spatial scales, and the amount of contrast reduction depends on many factors (haze optical thickness, vertical distribution, single scattering albedo, scattering geometry, spatial scale). Titan's haze is strongly forward scattering even near 1-µm wavelength and many RT codes do a poor job. Fortunately the problem is more tractable at longer wavelengths. We show how data from the Cassini VIMS and ISS instruments can be used to understand surface contrast and atmospheric haze properties.

  12. Russia needs a strong counterpart

    International Nuclear Information System (INIS)

    Slovak, K.; Marcan, P.

    2008-01-01

    In this paper an interview with the head of OMV, Wolfgang Ruttenstorfer is published. There is extract from this interview: Q: There have been attempts to take over MOL for a quite long time. Do you think you can still succeed? Since the beginning we kept saying that this would not happen from one day to another. But it may take two to three years. But we are positive that it is justified. Q: Resistance from MOL and the Hungarian government is strong. We have tried to persuade the Hungarian government. We offered them a split company management. A part of the management would be in Budapest. We would locate the management of the largest division - the refinery, there. And of course only the best could be part of the management. We would not nominate people according to their nationality, it would not matter whether the person was Austrian, Hungarian or Slovak. We want a Central European company, not Hungarian, Romanian or Slovak company. Q: Would the transaction still be attractive if, because of pressure exercised by Brussels, you had to sell Slovnaft or your refinery in Szazhalobatta? We do not intend to sell any refineries. Q: Rumours are spreading that the Commission may ask you to sell a refinery? We do not want to speculate. Let us wait and see what happens. We do not want to sell refineries. Q: It is said that OMV is coordinating or at least consulting its attempts to acquire MOL with Gazprom. There are many rumours in Central Europe. But I can tell you this is not true. We are interested in this merger because we feel the increasing pressure exercised by Kazakhstan and Russia. We, of course, have a good relationship with Gazprom which we have had enjoyed for over forty years. As indeed Slovakia has. Q: A few weeks ago Austrian daily Wirtschaftsblatt published an article about Gazprom's interest in OMV shares. That is gossip that is more than ten years' old. Similarly to the rumours that Gazprom is a shareholder of MOL. There are no negotiations with Gazprom

  13. Trade-Induced Atmospheric Mercury Deposition over China and Implications for Demand-Side Controls.

    Science.gov (United States)

    Chen, Long; Meng, Jing; Liang, Sai; Zhang, Haoran; Zhang, Wei; Liu, Maodian; Tong, Yindong; Wang, Huanhuan; Wang, Wei; Wang, Xuejun; Shu, Jiong

    2018-02-20

    Mercury (Hg) is of global concern because of its adverse effects on humans and the environment. In addition to long-range atmospheric transport, Hg emissions can be geographically relocated through economic trade. Here, we investigate the effect of China's interregional trade on atmospheric Hg deposition over China, using an atmospheric transport model and multiregional input-output analysis. In general, total atmospheric Hg deposition over China is 408.8 Mg yr -1 , and 32% of this is embodied in China's interregional trade, with the hotspots occurring over Gansu, Henan, Hebei, and Yunnan provinces. Interprovincial trade considerably redistributes atmospheric Hg deposition over China, with a range in deposition flux from -104% to +28%. Developed regions, such as the Yangtze River Delta (Shanghai, Jiangsu, and Zhejiang) and Guangdong, avoid Hg deposition over their geographical boundaries, instead causing additional Hg deposition over developing provinces. Bilateral interaction among provinces is strong over some regions, suggesting a need for joint mitigation, such as the Jing-Jin-Ji region (Beijing, Tianjin, and Hebei) and the Yangtze River Delta. Transferring advanced technology from developed regions to their developing trade partners would be an effective measure to mitigate China's Hg pollution. Our findings are relevant to interprovincial efforts to reduce trans-boundary Hg pollution in China.

  14. Nickel: makes stainless steel strong

    Science.gov (United States)

    Boland, Maeve A.

    2012-01-01

    Nickel is a silvery-white metal that is used mainly to make stainless steel and other alloys stronger and better able to withstand extreme temperatures and corrosive environments. Nickel was first identified as a unique element in 1751 by Baron Axel Fredrik Cronstedt, a Swedish mineralogist and chemist. He originally called the element kupfernickel because it was found in rock that looked like copper (kupfer) ore and because miners thought that "bad spirits" (nickel) in the rock were making it difficult for them to extract copper from it. Approximately 80 percent of the primary (not recycled) nickel consumed in the United States in 2011 was used in alloys, such as stainless steel and superalloys. Because nickel increases an alloy's resistance to corrosion and its ability to withstand extreme temperatures, equipment and parts made of nickel-bearing alloys are often used in harsh environments, such as those in chemical plants, petroleum refineries, jet engines, power generation facilities, and offshore installations. Medical equipment, cookware, and cutlery are often made of stainless steel because it is easy to clean and sterilize. All U.S. circulating coins except the penny are made of alloys that contain nickel. Nickel alloys are increasingly being used in making rechargeable batteries for portable computers, power tools, and hybrid and electric vehicles. Nickel is also plated onto such items as bathroom fixtures to reduce corrosion and provide an attractive finish.

  15. Forecasting global atmospheric CO2

    International Nuclear Information System (INIS)

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

    2014-01-01

    measurements and CO 2 in situ observations, as they become available in near-real time. In this way, the accumulation of errors in the atmospheric CO 2 forecast will be reduced. Improvements in the CO 2 forecast are also expected with the continuous developments in the operational IFS. (authors)

  16. Deuterium in atmospheric cycle

    International Nuclear Information System (INIS)

    Pontikis, M.C.

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

  17. Urban atmospheric contamination

    International Nuclear Information System (INIS)

    Baldasano Jose, M.

    1997-01-01

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

  18. Controlled Atmosphere Stunning

    NARCIS (Netherlands)

    Lambooij, E.; Gerritzen, M.A.

    2009-01-01

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

  19. Host trait combinations drive abundance and canopy distribution of atmospheric bromeliad assemblages.

    Science.gov (United States)

    Chaves, Cleber Juliano Neves; Dyonisio, Júlio César; Rossatto, Davi Rodrigo

    2016-01-01

    Epiphytes are strongly dependent on the conditions created by their host's traits and a certain degree of specificity is expected between them, even if these species are largely abundant in a series of tree hosts of a given environment, as in the case of atmospheric bromeliads. Despite their considerable abundance in these environments, we hypothesize that stochasticity alone cannot explain the presence and abundance of atmospheric bromeliads on host trees, since host traits could have a greater influence on the establishment of these bromeliads. We used secondary and reforested seasonal forests and three distinct silvicultures to test whether species richness, phylogenetic diversity and functional diversity of trees can predict the differential presence, abundance and distribution of atmospheric bromeliads on hosts. We compared the observed parameters of their assemblage with null models and performed successive variance hierarchic partitions of abundance and distribution of the assemblage to detect the influence of multiple traits of the tree hosts. Our results do not indicate direct relationships between the abundance of atmospheric bromeliads and phylogenetic or functional diversity of trees, but instead indicate that bromeliads occurred on fewer tree species than expected by chance. We distinguished functional tree patterns that can improve or reduce the abundance of atmospheric bromeliads, and change their distribution on branches and trunk. While individual tree traits are related to increased abundance, species traits are related to the canopy distribution of atmospheric bromeliad assemblages. A balance among these tree functional patterns drives the atmospheric bromeliad assemblage of the forest patches. Published by Oxford University Press on behalf of the Annals of Botany Company.

  20. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    Kaspi, Yohai [Department of Earth and Planetary Sciences, Weizmann Institute of Science, 234 Herzl st., 76100, Rehovot (Israel); Showman, Adam P., E-mail: yohai.kaspi@weizmann.ac.il [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States)

    2015-05-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.

  1. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    International Nuclear Information System (INIS)

    Kaspi, Yohai; Showman, Adam P.

    2015-01-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate

  2. Land-Ocean-Atmospheric Coupling Associated with Earthquakes

    Science.gov (United States)

    Prasad, A. K.; Singh, R. P.; Kumar, S.; Cervone, G.; Kafatos, M.; Zlotnicki, J.

    2007-12-01

    Earthquakes are well known to occur along the plate boundaries and also on the stable shield. The recent studies have shown existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes. We have carried out detailed analysis of multi sensor data (optical and microwave remote) to show existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes with focal depth up to 30 km and magnitude greater than 5.5. Complimentary nature of various land, ocean and atmospheric parameters will be demonstrated in getting an early warning information about an impending earthquake.

  3. Dynamics of Massive Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-10

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

  4. Reference Atmosphere for Mercury

    Science.gov (United States)

    Killen, Rosemary M.

    2002-01-01

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

  5. The response of the North Pacific Decadal Variability to strong tropical volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tao [Chinese Academy of Sciences, Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Beijing (China); Otteraa, Odd Helge [Uni Bjerknes Centre, Uni Research, Bergen (Norway); Bjerknes Center for Climate Research, Bergen (Norway); Gao, Yongqi [Chinese Academy of Sciences, Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Beijing (China); Bjerknes Center for Climate Research, Bergen (Norway); Nansen Environmental and Remote Sensing Center, Bergen (Norway); Wang, Huijun [Chinese Academy of Sciences, Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Beijing (China); Chinese Academy of Sciences, Climate Change Research Center, Institute of Atmospheric Physics, Beijing (China)

    2012-12-15

    In this study, the effects of volcanic forcing on North Pacific climate variability, on interannual to decadal time scales, are examined using climate model simulations covering the last 600 years. The model used is the Bergen Climate Model, a fully coupled atmosphere-ocean general circulation model. It is found that natural external forcings, such as tropical strong volcanic eruptions (SVEs) and variations in total solar irradiance, play an important role in regulating North Pacific Decadal Variability (NPDV). In response to tropical SVEs the lower stratospheric pole-to-equator temperature gradient is enhanced. The North polar vortex is strengthened, which forces a significant positive Arctic Oscillation. At the same time, dipole zonal wind anomalies associated with strong polar vortex propagate downward from the lower stratosphere. Through positive feedbacks in the troposphere, the surface westerly winds across the central North Pacific are significantly weakened, and positive sea level pressure anomalies are formed in the North Pacific. This anomalous surface circulation results in changes in the net heat fluxes and the oceanic advection across the North Pacific. As a result of this, warm water converges in the subtropical western North Pacific, where the surface waters in addition are heated by significantly reduced latent and sensible heat fluxes from the ocean. In the eastern and high-latitude North Pacific the ocean loses more heat, and large-scale decreases in sea surface temperatures are found. The overall response of this chain of events is that the North Pacific enters a negative phase of the Pacific decadal oscillation (PDO), and this negative phase of the PDO is maintained for several years. It is thus concluded that the volcanic forcing plays a key role in the phasing of the PDO. The model results furthermore highlight the important role of troposphere-stratosphere coupling, tropical-extratropical teleconnections and extratropical ocean-atmosphere

  6. Photochemistry of Planetary Atmospheres

    Science.gov (United States)

    Yung, Y. L.

    2005-12-01

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

  7. CASPER: Concordia Atmospheric SPectroscopy of Emitted Radiation

    Science.gov (United States)

    de Petris, M.; Catalano, A.; de Gregori, S.; Lamagna, L.; Lattanzi, V.; Luzzi, G.; Maoli, R.; Melchiorri, A.; Melchiorri, F.; Savini, G.; Vetrani, G. G.; Battistelli, E. S.; Valenziano, L.; Mandolesi, N.; Villa, F.; Cuttaia, F.; Ade, P. A. R.; Mauskopf, P.; Orlando, A.; Encrenaz, P.; Pardo, J. R.; Cernicharo, J.

    CASPER (Concordia Atmospheric SPectroscopy of Emitted Radiation) is a spectrometer proposed for installation at Dome C, devoted to measurements of atmospheric emission in the spectral region between 180 μm and 3 mm (3 55 cm-1). This instrument will be able to perform continuous spectral sampling at different altitudes at angular scales of 1°. From the recorded data it is possible to extract atmospheric transmittance within 1% in the whole wide operating band, together with water vapour content and O{2} and O{3} concentrations. CASPER will allow us to characterize the site for future FIR/mm telescopes. Atmospheric data recorded by CASPER will allow for correction of astrophysical and cosmological observations without the need for telescope-specific procedures and further loss of observation time with more precision in the observations themselves. Calibration of ground-based telescopes on known sky sources is strongly affected by atmospheric absorption. CASPER has this as its primary goal. The spectrometer is based on a Martin-Puplett interferometer. Two data sampling solutions will be performed: phase modulation & fast scan strategy. Sky radiation is collected towards the interferometer by an optical setup that allows the field of view, to explore the full 0° div 90° range of elevation angles. With a low spurious polarization instrument, monitoring of polarized atmospheric contribution will be possible.

  8. Recent Advances in Atmospheric Chemistry of Mercury

    Directory of Open Access Journals (Sweden)

    Lin Si

    2018-02-01

    Full Text Available Mercury is one of the most toxic metals and has global importance due to the biomagnification and bioaccumulation of organomercury via the aquatic food web. The physical and chemical transformations of various mercury species in the atmosphere strongly influence their composition, phase, transport characteristics and deposition rate back to the ground. Modeling efforts to assess global cycling of mercury require an accurate understanding of atmospheric mercury chemistry. Yet, there are several key uncertainties precluding accurate modeling of physical and chemical transformations. We focus this article on recent studies (since 2015 on improving our understanding of the atmospheric chemistry of mercury. We discuss recent advances in determining the dominant atmospheric oxidant of elemental mercury (Hg0 and understanding the oxidation reactions of Hg0 by halogen atoms and by nitrate radical (NO3—in the aqueous reduction of oxidized mercury compounds (HgII as well as in the heterogeneous reactions of Hg on atmospheric-relevant surfaces. The need for future research to improve understanding of the fate and transformation of mercury in the atmosphere is also discussed.

  9. 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).

  10. Atmospheric ionisation in Snowdonia

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-23

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

  11. LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

    International Nuclear Information System (INIS)

    Zugger, M. E.; Kane, T. J.; Kasting, J. F.; Williams, D. M.; Philbrick, C. R.

    2010-01-01

    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) = 180 0 , whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30 0 . Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74 0 ; 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 = 90 0 , 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.

  12. Modeling the atmospheric chemistry of TICs

    Science.gov (United States)

    Henley, Michael V.; Burns, Douglas S.; Chynwat, Veeradej; Moore, William; Plitz, Angela; Rottmann, Shawn; Hearn, John

    2009-05-01

    An atmospheric chemistry model that describes the behavior and disposition of environmentally hazardous compounds discharged into the atmosphere was coupled with the transport and diffusion model, SCIPUFF. The atmospheric chemistry model was developed by reducing a detailed atmospheric chemistry mechanism to a simple empirical effective degradation rate term (keff) that is a function of important meteorological parameters such as solar flux, temperature, and cloud cover. Empirically derived keff functions that describe the degradation of target toxic industrial chemicals (TICs) were derived by statistically analyzing data generated from the detailed chemistry mechanism run over a wide range of (typical) atmospheric conditions. To assess and identify areas to improve the developed atmospheric chemistry model, sensitivity and uncertainty analyses were performed to (1) quantify the sensitivity of the model output (TIC concentrations) with respect to changes in the input parameters and (2) improve, where necessary, the quality of the input data based on sensitivity results. The model predictions were evaluated against experimental data. Chamber data were used to remove the complexities of dispersion in the atmosphere.

  13. Degassing of reduced carbon from planetary basalts.

    Science.gov (United States)

    Wetzel, Diane T; Rutherford, Malcolm J; Jacobsen, Steven D; Hauri, Erik H; Saal, Alberto E

    2013-05-14

    Degassing of planetary interiors through surface volcanism plays an important role in the evolution of planetary bodies and atmospheres. On Earth, carbon dioxide and water are the primary volatile species in magmas. However, little is known about the speciation and degassing of carbon in magmas formed on other planets (i.e., Moon, Mars, Mercury), where the mantle oxidation state [oxygen fugacity (fO2)] is different from that of the Earth. Using experiments on a lunar basalt composition, we confirm that carbon dissolves as carbonate at an fO2 higher than -0.55 relative to the iron wustite oxygen buffer (IW-0.55), whereas at a lower fO2, we discover that carbon is present mainly as iron pentacarbonyl and in smaller amounts as methane in the melt. The transition of carbon speciation in mantle-derived melts at fO2 less than IW-0.55 is associated with a decrease in carbon solubility by a factor of 2. Thus, the fO2 controls carbon speciation and solubility in mantle-derived melts even more than previous data indicate, and the degassing of reduced carbon from Fe-rich basalts on planetary bodies would produce methane-bearing, CO-rich early atmospheres with a strong greenhouse potential.

  14. Predominant nonlinear atmospheric response to meridional shift of the Gulf Stream path from the WRF atmospheric model simulations

    Science.gov (United States)

    Seo, H.; Kwon, Y. O.; Joyce, T. M.

    2016-02-01

    A remarkably strong nonlinear behavior of the atmospheric circulation response to North Atlantic SST anomalies (SSTA) is revealed from a set of large-ensemble, high-resolution, and hemispheric-scale Weather Research and Forecasting (WRF) model simulations. The model is forced with the SSTA associated with meridional shift of the Gulf Stream (GS) path, constructed from a lag regression of the winter SST on a GS Index from observation. Analysis of the systematic set of experiments with SSTAs of varied amplitudes and switched signs representing various GS-shift scenarios provides unique insights into mechanism for emergence and evolution of transient and equilibrium response of atmospheric circulation to extratropical SSTA. Results show that, independent of sign of the SSTA, the equilibrium response is characterized by an anomalous trough over the North Atlantic Ocean and the Western Europe concurrent with enhanced storm track, increased rainfall, and reduced blocking days. To the north of the anomalous low, an anomalous ridge emerges over the Greenland, Iceland, and Norwegian Seas accompanied by weakened storm track, reduced rainfall and increased blocking days. This nonlinear component of the total response dominates the weak and oppositely signed linear response that is directly forced by the SSTA, yielding an anomalous ridge (trough) downstream of the warm (cold) SSTA. The amplitude of the linear response is proportional to that of the SSTA, but this is masked by the overwhelmingly strong nonlinear behavior showing no clear correspondence to the SSTA amplitude. The nonlinear pattern emerges 3-4 weeks after the model initialization in November and reaches its first peak amplitude in December/January. It appears that altered baroclinic wave activity due to the GS SSTA in November lead to low-frequency height responses in December/January through transient eddy vorticity flux convergence.

  15. Nighttime atmospheric chemistry of iodine

    Science.gov (United States)

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

    2016-12-01

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

  16. Atmospheres of Brown Dwarfs

    Science.gov (United States)

    Wang, Ruoyan; Seay, Christopher

    2018-01-01

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

  17. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

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

  18. 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)

  19. CARBON NEUTRON STAR ATMOSPHERES

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  20. Exoplanet atmospheres physical processes

    CERN Document Server

    Seager, Sara

    2010-01-01

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

  1. Origin of atmosphere

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-01-01

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

  2. The origin of atmosphere

    International Nuclear Information System (INIS)

    Marx, Gy.

    1975-01-01

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

  3. Behavior of Particle Depots in Molten Silicon During Float-Zone Growth in Strong Magnetic Fields

    Science.gov (United States)

    Jauss, T.; Croell, A.; SorgenFrei, T.; Azizi, M.; Reimann, C.; Friedrich, J.; Volz, M. P.

    2014-01-01

    Solar cells made from directionally solidified silicon cover 57% of the photovoltaic industry's market [1]. One major issue during directional solidification of silicon is the precipitation of foreign phase particles. These particles, mainly SiC and Si3N4, are precipitated from the dissolved crucible coating, which is made of silicon nitride, and the dissolution of carbon monoxide from the furnace atmosphere. Due to their hardness and size of several hundred micrometers, those particles can lead to severe problems during the wire sawing process for wafering the ingots. Additionally, SiC particles can act as a shunt, short circuiting the solar cell. Even if the particles are too small to disturb the wafering process, they can lead to a grit structure of silicon micro grains and serve as sources for dislocations. All of this lowers the yield of solar cells and reduces the performance of cells and modules. We studied the behaviour of SiC particle depots during float-zone growth under an oxide skin, and strong static magnetic fields. For high field strengths of 3T and above and an oxide layer on the sample surface, convection is sufficiently suppressed to create a diffusive like regime, with strongly dampened convection [2, 3]. To investigate the difference between atomically rough phase boundaries and facetted growth, samples with [100] and [111] orientation were processed.

  4. 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....

  5. 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...

  6. Intensifying the Atmospheric

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä

    2012-01-01

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

  7. Atmospheric release advisory capability

    International Nuclear Information System (INIS)

    Sullivan, T.J.

    1981-01-01

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

  8. Atmospheric pollution in Lisbon urban atmosphere

    Science.gov (United States)

    Oliveira, C.

    2009-04-01

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

  9. Atmospheric rivers: a mini-review

    Directory of Open Access Journals (Sweden)

    Luis eGimeno

    2014-03-01

    Full Text Available Atmospheric rivers (ARs are narrow regions responsible for the majority of the poleward water vapour transport across the midlatitudes. They are characterized by high water vapour content and strong low level winds, and form a part of the broader warm conveyor belt of extratropical cyclones. Although the meridional water vapour transport within ARs is critical for water resources, ARs can also cause disastrous floods especially when encountering mountainous terrain. They were labelled as atmospheric rivers in the 1990s, and have since become a well-studied feature of the midlatitude climate. We briefly review the conceptual model, the methods used to identify them, their main climatological characteristics, their impacts, the predictive ability of numerical weather prediction models, their relationship with large-scale ocean-atmosphere dynamics, possible changes under future climates, and some future challenges.

  10. Atmospheric Chemistry of Micrometeoritic Organic Compounds

    Science.gov (United States)

    Kress, M. E.; Belle, C. L.; Pevyhouse, A. R.; Iraci, L. T.

    2011-01-01

    Micrometeorites approx.100 m in diameter deliver most of the Earth s annual accumulation of extraterrestrial material. These small particles are so strongly heated upon atmospheric entry that most of their volatile content is vaporized. Here we present preliminary results from two sets of experiments to investigate the fate of the organic fraction of micrometeorites. In the first set of experiments, 300 m particles of a CM carbonaceous chondrite were subject to flash pyrolysis, simulating atmospheric entry. In addition to CO and CO2, many organic compounds were released, including functionalized benzenes, hydrocarbons, and small polycyclic aromatic hydrocarbons. In the second set of experiments, we subjected two of these compounds to conditions that simulate the heterogeneous chemistry of Earth s upper atmosphere. We find evidence that meteor-derived compounds can follow reaction pathways leading to the formation of more complex organic compounds.

  11. Infrared observations of planetary atmospheres

    International Nuclear Information System (INIS)

    Orton, G.S.; Baines, K.H.; Bergstralh, J.T.

    1988-01-01

    The goal of this research in to obtain infrared data on planetary atmospheres which provide information on several aspects of structure and composition. Observations include direct mission real-time support as well as baseline monitoring preceding mission encounters. Besides providing a broader information context for spacecraft experiment data analysis, observations will provide the quantitative data base required for designing optimum remote sensing sequences and evaluating competing science priorities. In the past year, thermal images of Jupiter and Saturn were made near their oppositions in order to monitor long-term changes in their atmospheres. Infrared images of the Jovian polar stratospheric hot spots were made with IUE observations of auroral emissions. An exploratory 5-micrometer spectrum of Uranus was reduced and accepted for publication. An analysis of time-variability of temperature and cloud properties of the Jovian atomsphere was made. Development of geometric reduction programs for imaging data was initiated for the sun workstation. Near-infrared imaging observations of Jupiter were reduced and a preliminary analysis of cloud properties made. The first images of the full disk of Jupiter with a near-infrared array camera were acquired. Narrow-band (10/cm) images of Jupiter and Saturn were obtained with acousto-optical filters

  12. Conduction properties of strongly interacting Fermions

    Science.gov (United States)

    Brantut, Jean-Philippe; Stadler, David; Krinner, Sebastian; Meineke, Jakob; Esslinger, Tilman

    2013-05-01

    We experimentally study the transport process of ultracold fermionic atoms through a mesoscopic, quasi two-dimensional channel connecting macroscopic reservoirs. By observing the current response to a bias applied between the reservoirs, we directly access the resistance of the channel in a manner analogous to a solid state conduction measurement. The resistance is further controlled by a gate potential reducing the atomic density in the channel, like in a field effect transistor. In this setup, we study the flow of a strongly interacting Fermi gas, and observe a striking drop of resistance with increasing density in the channel, as expected at the onset of superfluidity. We relate the transport properties to the in-situ evolution of the thermodynamic potential, providing a model independant thermodynamic scale. The resistance is compared to that of an ideal Fermi gas in the same geometry, which shows an order of magnitude larger resistance, originating from the contact resistance between the channel and the reservoirs. The extension of this study to a channel containing a tunable disorder is briefly outlined.

  13. Quantum entanglement in strong-field ionization

    Science.gov (United States)

    Majorosi, Szilárd; Benedict, Mihály G.; Czirják, Attila

    2017-10-01

    We investigate the time evolution of quantum entanglement between an electron, liberated by a strong few-cycle laser pulse, and its parent ion core. Since the standard procedure is numerically prohibitive in this case, we propose a method to quantify the quantum correlation in such a system: we use the reduced density matrices of the directional subspaces along the polarization of the laser pulse and along the transverse directions as building blocks for an approximate entanglement entropy. We present our results, based on accurate numerical simulations, in terms of several of these entropies, for selected values of the peak electric-field strength and the carrier-envelope phase difference of the laser pulse. The time evolution of the mutual entropy of the electron and the ion-core motion along the direction of the laser polarization is similar to our earlier results based on a simple one-dimensional model. However, taking into account also the dynamics perpendicular to the laser polarization reveals a surprisingly different entanglement dynamics above the laser intensity range corresponding to pure tunneling: the quantum entanglement decreases with time in the over-the-barrier ionization regime.

  14. Strong Bisimilarity of Simple Process Algebras

    DEFF Research Database (Denmark)

    Srba, Jirí

    2003-01-01

    We study bisimilarity and regularity problems of simple process algebras. In particular, we show PSPACE-hardness of the following problems: (i) strong bisimilarity of Basic Parallel Processes (BPP), (ii) strong bisimilarity of Basic Process Algebra (BPA), (iii) strong regularity of BPP, and (iv......) strong regularity of BPA. We also demonstrate NL-hardness of strong regularity problems for the normed subclasses of BPP and BPA. Bisimilarity problems of simple process algebras are introduced in a general framework of process rewrite systems, and a uniform description of the new techniques used...

  15. Strongly nonlinear dynamics of electrolytes in large ac voltages

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bazant, Martin Z.; Bruus, Henrik

    2010-01-01

    to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional...

  16. Theory of Spin Waves in Strongly Anisotropic Magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Cooke, J. F.

    1976-01-01

    A new infinite-order perturbation approach to the theory of spin waves in strongly anisotropic magnets is introduced. The system is transformed into one with effective two-ion anisotropy and considerably reduced ground-state corrections. A general expression for the spin-wave energy, valid to any...

  17. Wave function of free electron in a strong laser plasma

    International Nuclear Information System (INIS)

    Zhu Shitong; Shen Wenda; Guo Qizhi

    1993-01-01

    The wave function of free electron in a strong laser plasma is obtained by solving exactly the Dirac equation in a curved space-time with optical metric for the laser plasma. When the laser field is diminished to zero, the wave function is naturally reduced to relativistic wave function of free electron. The possible application of the wave function is discussed

  18. Quantum field model of strong-coupling binucleon

    International Nuclear Information System (INIS)

    Amirkhanov, I.V.; Puzynin, I.V.; Puzynina, T.P.; Strizh, T.A.; Zemlyanaya, E.V.; Lakhno, V.D.

    1996-01-01

    The quantum field binucleon model for the case of the nucleon spot interaction with the scalar and pseudoscalar meson fields is considered. It is shown that the nonrelativistic problem of the two nucleon interaction reduces to the one-particle problem. For the strong coupling limit the nonlinear equations describing two nucleons in the meson field are developed [ru

  19. Application of strong phosphoric acid to radiochemistry

    International Nuclear Information System (INIS)

    Terada, Kikuo

    1977-01-01

    Not only inorganic and organic compounds but also natural substrances, such as accumulations in soil, are completely decomposed and distilled by heating with strong phosphoric acid for 30 to 50 minutes. As applications of strong phosphoric acid to radiochemistry, determination of uranium and boron by use of solubilization effect of this substance, titration of uranyl ion by use of sulfuric iron (II) contained in this substance, application to tracer experiment, and determination of radioactive ruthenium in environmental samples are reviewed. Strong phosphoric acid is also applied to activation analysis, for example, determination of N in pyrographite with iodate potassium-strong phosphoric acid method, separation of Os and Ru with sulfuric cerium (IV) - strong phosphoric acid method or potassium dechromate-strong phosphoric acid method, analysis of Se, As and Sb rocks and accumulations with ammonium bromide, sodium chloride and sodium bromide-strong phosphoric acid method. (Kanao, N.)

  20. Frost protection for atmospheric cooling tower

    International Nuclear Information System (INIS)

    Legrand, G.

    1987-01-01

    When the atmospheric temperature is near or lower than zero it is necessary to reduce the air flow entering in a cooling tower. A wire netting mounted on the air inlet is sprinkled with cold water. The level of the ice curtain and consequently the air flow is regulated by aspersion by hot water [fr

  1. Atmospheric Pollution: Its Origins and Prevention.

    Science.gov (United States)

    Meetham, A. R.

    Although atmospheric pollution can be reduced or eliminated in many different ways, each way involves questions of economics, the time factor, availability of materials, priority over other urgent reforms, and individual and social psychology. To provide a basis for consideration of these questions, this book gives information not only about the…

  2. 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

  3. Formation and Evolution of the Atmosphere on Early Titan

    Science.gov (United States)

    Marounina, N.; Tobie, G.; Carpy, S.; Monteux, J.; Charnay, B.; Grasset, O.

    2014-12-01

    The mass and composition of Titan's massive atmosphere, which is dominated by N2 and CH4 at present, have probably varied all along its history owing to a combination of exogenous and endogenous processes. In a recent study, we investigated its fate during the Late Heavy Bombardment (LHB) by modeling the competitive loss and supply of volatiles by cometary impacts and their consequences on the atmospheric balance. We examine the emergence of an atmosphere as well as the evolution of a primitive atmosphere of various sizes and compositions. By considering an impactor population characteristic of the LHB, we showed that an atmosphere with a mass equivalent to the present-day one cannot be formed during the LHB era. Our calculations indicated that the high-velocity impacts during the LHB led to a strong atmospheric erosion, so that the pre-LHB atmosphere should be 5 to 7 times more massive than at present (depending mostly on the albedo), in order to sustain an atmosphere equivalent to the present-day one. This implies that either a massive atmosphere was formed on Titan during its accretion or that the nitrogen-rich atmosphere was generated after the LHB.To investigate the primitive atmosphere of the satellite, we consider chemical exchanges of volatils between a global water ocean at Titan's surface, generated by impact heating during the accretion and an atmosphere. We are currently developing a liquid-vapor equilibrium model for various initial oceanic composition to investigate how a massive atmosphere may be generated during the satellite growth and how it may evolve toward a composition dominated by N2. More generally, our model address how atmosphere may be generated in water-rich objects, which may be common around other stars.

  4. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    Science.gov (United States)

    Graven, Heather D

    2015-08-04

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  5. Atmospheric ions and pollution

    International Nuclear Information System (INIS)

    Renoux, A.

    1977-01-01

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

  6. 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.

  7. 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...

  8. The Atmosphere and Climate of Venus

    Science.gov (United States)

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

    this chapter in terms of the initial forcing due to a perturbation, radiative response, and indirect responses, which are feedbacks — either positive or negative. When applied to one Venus climate model, we found that the albedo-radiative feedback is more important than greenhouse forcing for small changes in atmospheric H2O and SO2. An increase in these gases cools the planet by making the clouds brighter. On geologic timescales the reaction of some atmospheric species (SO2, CO, OCS, S, H2O, H2S, HCl, HF) with surface minerals could cause significant changes in atmospheric composition. Laboratory data and thermochemical modeling have been important for showing that atmospheric SO2 would be depleted in ~10 m.y. if carbonates are available at the surface. Without replenishment, the clouds would disappear. Alternatively, the oxidation of pyrite could add SO2 to the atmosphere while producing stable Fe oxides at the surface. The correlation of near-infrared high emissivity (dark) surface features with three young, large volcanos on Venus is strong evidence for recent volcanic activity at these sites, certainly over the timescale necessary to support the clouds. We address the nature of heterogeneous reactions with the surface and the implications for climate change on Venus. Chemical and mineralogical signatures of past climates must exist at the surface and below, so in situ experiments on the composition of surface layers are vital for reconstructing Venus' past climate. Many of the most Earth-like planets found around other stars will probably resemble Venus or a younger version of Venus. We finish the chapter with discussing what Venus can tell us about life in the universe, since it is an example of a planetary climate rendered uninhabitable. It also resembles our world's likely future. As with the climate history of Venus, however, the timing of predictable climate transitions on the Earth is poorly constrained by the data.

  9. Influence of Gas Atmosphere Dew Point on the Galvannealing of CMnSi TRIP Steel

    Science.gov (United States)

    Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

    2013-11-01

    The Fe-Zn reaction occurring during the galvannealing of a Si-bearing transformation-induced plasticity (TRIP) steel was investigated by field-emission electron probe microanalysis and field-emission transmission electron microscopy. The galvannealing was simulated after hot dipping in a Zn bath containing 0.13 mass pct Al at 733 K (460 °C). The galvannealing temperature was in the range of 813 K to 843 K (540 °C to 570 °C). The kinetics and mechanism of the galvannealing reaction were strongly influenced by the gas atmosphere dew point (DP). After the galvannealing of a panel annealed in a N2+10 pct H2 gas atmosphere with low DPs [213 K and 243 K (-60 °C and -30 °C)], the coating layer consisted of δ (FeZn10) and η (Zn) phase crystals. The Mn-Si compound oxides formed during intercritical annealing were present mostly at the steel/coating interface after the galvannealing. Galvannealing of a panel annealed in higher DP [263 K and 273 K, and 278 K (-10 °C, 0 °C, and +5 °C)] gas atmospheres resulted in a coating layer consisting of δ and Г (Fe3Zn10) phase crystals, and a thin layer of Г 1 (Fe11Zn40) phase crystals at the steel/coating interface. The Mn-Si oxides were distributed homogeneously throughout the galvannealed (GA) coating layer. When the surface oxide layer thickness on panels annealed in a high DP gas atmosphere was reduced, the Fe content at the GA coating surface increased. Annealing in a higher DP gas atmosphere improved the coating quality of the GA panels because a thinner layer of oxides was formed. A high DP atmosphere can therefore significantly contribute to the suppression of Zn-alloy coating defects on CMnSi TRIP steel processed in hot dip galvanizing lines.

  10. CHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Thomas P. [NASA Ames Research Center, Space Science and Astrobiology Division, M.S. 245-6, Moffett Field, CA 94035 (United States); Line, Michael R.; Montero, Cezar; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lustig-Yaeger, Jacob [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Luther, Kyle, E-mail: tom.greene@nasa.gov [Department of Physics, University of California, 366 LeConte Hall MC 7300, Berkeley, CA 94720 (United States)

    2016-01-20

    We explore how well spectra from the James Webb Space Telescope (JWST) will likely constrain bulk atmospheric properties of transiting exoplanets. We start by modeling the atmospheres of archetypal hot Jupiter, warm Neptune, warm sub-Neptune, and cool super-Earth planets with atmospheres that are clear, cloudy, or of high mean molecular weight (HMMW). Next we simulate the λ = 1–11 μm transmission and emission spectra of these systems for several JWST instrument modes for single-transit or single-eclipse events. We then perform retrievals to determine how well temperatures and molecular mixing ratios (CH{sub 4}, CO, CO{sub 2}, H{sub 2}O, NH{sub 3}) can be constrained. We find that λ = 1–2.5 μm transmission spectra will often constrain the major molecular constituents of clear solar-composition atmospheres well. Cloudy or HMMW atmospheres will often require full 1–11 μm spectra for good constraints, and emission data may be more useful in cases of sufficiently high F{sub p} and high F{sub p}/F{sub *}. Strong temperature inversions in the solar-composition hot-Jupiter atmosphere should be detectable with 1–2.5+ μm emission spectra, and 1–5+ μm emission spectra will constrain the temperature–pressure profiles of warm planets. Transmission spectra over 1–5+ μm will constrain [Fe/H] values to better than 0.5 dex for the clear atmospheres of the hot and warm planets studied. Carbon-to-oxygen ratios can be constrained to better than a factor of 2 in some systems. We expect that these results will provide useful predictions of the scientific value of single-event JWST spectra until its on-orbit performance is known.

  11. Environmental consequences of atmospheric krypton-85

    International Nuclear Information System (INIS)

    Boeck, W.L.

    1978-01-01

    This project examines the thesis that atmospheric background ionization is relevant to the understanding of weather. Projections of future world-wide use of nuclear energy imply that sufficient krypton-85 will be produced and may be released to significantly alter the natural ionization background. The scope of the project includes an assessment of krypton-85 on the electrical aspects of the atmosphere as well as the consequences of an altered electrical state of the atmosphere. The results of a first approximation model for the effects of krypton-85 on the atmosphere show that the electric field at the surface of the ocean would be reduced by about 25 percent and at a continental station by about 15 percent. At about two kilometers altitude, the electric field would be reduced by about 14 percent over the oceans and 16 percent over the land. The effects decrease quickly with increasing altitude. Analytical studies of the equations for fair weather atmospheric electricity yield solutions suitable for the interpretation of time dependent phenomena with periods longer than a few seconds. A brief analysis shows that a perfect assessment is not necessary to make an error-free decision regarding krypton-85 control measures. From the viewpoint of a decision-maker, those aspects that could swing the decision from one alternative to another are priority areas for analysis

  12. On the permanent hip-stabilizing effect of atmospheric pressure.

    Science.gov (United States)

    Prietzel, Torsten; Hammer, Niels; Schleifenbaum, Stefan; Kaßebaum, Eric; Farag, Mohamed; von Salis-Soglio, Georg

    2014-08-22

    Hip joint dislocations related to total hip arthroplasty (THA) are a common complication especially in the early postoperative course. The surgical approach, the alignment of the prosthetic components, the range of motion and the muscle tone are known factors influencing the risk of dislocation. A further factor that is discussed until today is atmospheric pressure which is not taken into account in the present THA concepts. The aim of this study was to investigate the impact of atmospheric pressure on hip joint stability. Five joint models (Ø 28-44 mm), consisting of THA components were hermetically sealed with a rubber capsule, filled with a defined amount of fluid and exposed to varying ambient pressure. Displacement and pressure sensors were used to record the extent of dislocation related to intraarticular and ambient pressure. In 200 experiments spontaneous dislocations of the different sized joint models were reliably observed once the ambient pressure was lower than 6.0 kPa. Increasing the ambient pressure above 6.0 kPa immediately and persistently reduced the joint models until the ambient pressure was lowered again. Displacement always exceeded half the diameter of the joint model and was independent of gravity effects. This experimental study gives strong evidence that the hip joint is permanently stabilized by atmospheric pressure, confirming the theories of Weber and Weber (1836). On basis of these findings the use of larger prosthetic heads, capsular repair and the deployment of an intracapsular Redon drain are proposed to substantially decrease the risk of dislocation after THA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Composition of Estonian atmosphere

    International Nuclear Information System (INIS)

    Punning, J. M.; Karindi, A.

    1996-01-01

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

  14. Atmospheric correction of satellite data

    Science.gov (United States)

    Shmirko, Konstantin; Bobrikov, Alexey; Pavlov, Andrey

    2015-11-01

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

  15. Natural atmospheric radioactivity

    International Nuclear Information System (INIS)

    Renoux, A.

    1986-01-01

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

  16. Atmosphere beyond Poetics

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2014-01-01

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

  17. Global atmospheric changes.

    Science.gov (United States)

    Piver, W T

    1991-12-01

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

  18. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    Crawford, T.V.

    1977-01-01

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

  19. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    Crawford, T.V.

    1978-01-01

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

  20. Severe asthma with markedly increased asbestos of 2 types & TXB2, and markedly reduced acetylcholine, DHEA & drug uptake in parts of upper lungs, & similar abnormalities at respiratory & cardiac center of medulla oblongata: complete elimination of this asthma within 15 days using one optimal dose of astragalus & application of strong red light & EMF neutralizer on respiratory centers of abnormal medulla oblongata.

    Science.gov (United States)

    Omura, Yoshiaki; Henoch, Avraham; Shimotsuura, Yasuhira; Duvvi, Harsha; Kawashima, Hiroshi; Ohki, Motomu

    2009-01-01

    When the window of an Asbestos-contaminated room from a broken ceiling was opened wide, A 73 year-old male physician of Oriental origin, who was sitting in the next room, suddenly developed a severe asthma attack, which did not stop by the use of a hand-held Albuterol inhaler. Temporary relief was obtained only by using a Compressor-Nebulizer (Inspiration 626 with Albuterol Sulfate Inhalation Solution 0.083%). During the attack, abnormal areas were discovered at the upper lobes of both lungs, where Thromboxane B2 (TXB2) was markedly increased to 500 ng (BDORT units) (the rest of the lung had about 2.5 ng), 2 types of Asbestos (Chrysotile and Crocidolite) were abnormally increased to 0.120-0.135 mg, (BDORT units) Acetylcholine was markedly reduced to 0.5 ng (the rest of the lung was low, about 100 ng), DHEA was extremely reduced to 1 ng (the rest of the lung had about 52 ng), and telomere was less than 1 yg (= 10(-24) g). Bacterial & viral infections were also present in these abnormal areas, but no antibiotics entered the abnormal parts of the lungs. Therefore, one optimal dose of Astragalus was given once, which resulted in a rapid continuous excretion of large amounts of the above 2 types of Asbestos & TXB2 in urine & sputum, and Asthma symptoms reduced slightly in severity. Additional acupuncture & shiatsu given on all the known acupuncture points for lung disease only created slight, temporary improvement. Then, the respiratory & cardiac center of the Medulla Oblongata was found to have similar abnormalities as the lungs. Therefore, 100 mW output of Light Emitting Diode of red spectra (650 nm center spectrum) was projected on the abnormal area of the medulla oblongata on the back of the head. This resulted drug uptake of on and off and significantly reduced difficulty of breathing. Additional application of the EMF Neutralizer on the abnormal area of the Medulla Oblongata for 3 hours resulted in continuous drug uptake and complete disappearance of asthma. As a

  1. Strong Stationary Duality for Diffusion Processes

    OpenAIRE

    Fill, James Allen; Lyzinski, Vince

    2014-01-01

    We develop the theory of strong stationary duality for diffusion processes on compact intervals. We analytically derive the generator and boundary behavior of the dual process and recover a central tenet of the classical Markov chain theory in the diffusion setting by linking the separation distance in the primal diffusion to the absorption time in the dual diffusion. We also exhibit our strong stationary dual as the natural limiting process of the strong stationary dual sequence of a well ch...

  2. Strongly correlating liquids and their isomorphs

    OpenAIRE

    Pedersen, Ulf R.; Gnan, Nicoletta; Bailey, Nicholas P.; Schröder, Thomas B.; Dyre, Jeppe C.

    2010-01-01

    This paper summarizes the properties of strongly correlating liquids, i.e., liquids with strong correlations between virial and potential energy equilibrium fluctuations at constant volume. We proceed to focus on the experimental predictions for strongly correlating glass-forming liquids. These predictions include i) density scaling, ii) isochronal superposition, iii) that there is a single function from which all frequency-dependent viscoelastic response functions may be calculated, iv) that...

  3. Atom collisions in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Smirnov, V.S.; Chaplik, A.V.

    1976-01-01

    It is shown that the long-range part of interatomic interaction is considerably altered in a strong electromagnetic field. Instead of the van der Waals law the potential asymptote can best be described by a dipole-dipole R -3 law. Impact broadening and the line shift in a strong nonresonant field are calculated. The possibility of bound states of two atoms being formed in a strong light field is discussed

  4. Modified Atmosphere Packaging of tomatoes; controlling gas and humidity

    NARCIS (Netherlands)

    Evelo, R.G.; Horst, J.

    1996-01-01

    Modified atmosphere (MA) packaging technology is a modern technique of which the application is steadily growing. Its essence is to reduce the decay of perishable produce by creating a special atmosphere around the produce. The MA factors influencing the quality behaviour of the produce are oxygen

  5. Aspects of the atmospheric surface layers on Mars and Earth

    DEFF Research Database (Denmark)

    Larsen, Søren Ejling; Ejsing Jørgensen, Hans; Landberg, L.

    2002-01-01

    and mean flow on Mars is found to obey the same scaling laws as on Earth. The largest micrometeorological differences between the two atmospheres are associated with the low air density of the Martian atmosphere. Together with the virtual absence of water vapour, it reduces the importance...

  6. Dispersion and transport of atmospheric pollutants

    International Nuclear Information System (INIS)

    Cieslik, S.

    1991-01-01

    This paper presents the physical mechanisms that govern the dispersion and transport of air pollutant; the influence of the state of the 'carrying fluid', i.e. the role of meteorology; and finally, outlines the different techniques of assessing the process. Aspects of physical mechanisms and meteorology covered include: fate of an air pollutant; turbulence and dispersion; transport; wind speed and direction; atmospheric stability; and the role of atmospheric water. Assessment techniques covered are: concentrations measurements; modelling meteorological observations; and tracer releases. It is concluded that the only way to reduce air pollution is to pollute less. 10 refs., 12 figs., 2 tabs

  7. Seasonal atmospheric extinction

    International Nuclear Information System (INIS)

    Mikhail, J.S.

    1979-01-01

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

  8. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-01

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

  9. Atmospheric muons in Hanoi

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  10. Climate and atmospheric research

    International Nuclear Information System (INIS)

    Kramer, G.; Schumacher, R.

    1992-01-01

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

  11. 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.

  12. 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...

  13. Atmospheric neutrino challenges

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-08-15

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

  14. Atmosphere as colloid

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  15. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  16. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Perkins, D.H.

    1984-01-01

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

  17. Atoms and atmosphere

    International Nuclear Information System (INIS)

    Megie, G.

    1994-01-01

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

  18. Inert atmosphere system for plutonium processing gloveboxes

    International Nuclear Information System (INIS)

    Bogard, C.F.; Calkins, K.W.; Rogers, R.F.

    1975-01-01

    Recent efforts to reduce fire hazards in plutonium processing operations are described. In such operations, the major environmental controls are developed through various kinds of glovebox systems. In evaluating the air-atmosphere glovebox systems, formerly in use at Rocky Flats and many other plants, a decision was made to convert to a recirculating ''inert'' atmosphere. The inert atmosphere consists of nitrogen, supplied from an on-site generating plant, diluting oxygen content to one to 5 percent by volume. Problems encountered during the change over included: determination of all factors influencing air leakage into the system, and reducing leakage to the practical minimum; meeting all fire and safety standards on the filter plenum and exhaust systems; provision for converting portions of the system to an air atmosphere to conduct maintenance work; inclusion of oxygen analyzers throughout the system to check gas quality and monitor for leaks; and the use of automatic controls to protect against a variety of potential malfunctions. The current objectives to reduce fire hazards have been met and additional safeguards were added. The systems are operating satisfactorily. (U.S.)

  19. ESA Atmospheric Toolbox

    Science.gov (United States)

    Niemeijer, Sander

    2017-04-01

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

  20. Hyperspectral material identification on radiance data using single-atmosphere or multiple-atmosphere modeling

    Science.gov (United States)

    Mariano, Adrian V.; Grossmann, John M.

    2010-11-01

    Reflectance-domain methods convert hyperspectral data from radiance to reflectance using an atmospheric compensation model. Material detection and identification are performed by comparing the compensated data to target reflectance spectra. We introduce two radiance-domain approaches, Single atmosphere Adaptive Cosine Estimator (SACE) and Multiple atmosphere ACE (MACE) in which the target reflectance spectra are instead converted into sensor-reaching radiance using physics-based models. For SACE, known illumination and atmospheric conditions are incorporated in a single atmospheric model. For MACE the conditions are unknown so the algorithm uses many atmospheric models to cover the range of environmental variability, and it approximates the result using a subspace model. This approach is sometimes called the invariant method, and requires the choice of a subspace dimension for the model. We compare these two radiance-domain approaches to a Reflectance-domain ACE (RACE) approach on a HYDICE image featuring concealed materials. All three algorithms use the ACE detector, and all three techniques are able to detect most of the hidden materials in the imagery. For MACE we observe a strong dependence on the choice of the material subspace dimension. Increasing this value can lead to a decline in performance.

  1. Comets, impacts, and atmospheres

    Science.gov (United States)

    Owen, Tobias; Bar-Nun, Akiva

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

  2. On the Strong Direct Summand Conjecture

    Science.gov (United States)

    McCullough, Jason

    2009-01-01

    In this thesis, our aim is the study the Vanishing of Maps of Tor Conjecture of Hochster and Huneke. We mainly focus on an equivalent characterization called the Strong Direct Summand Conjecture, due to N. Ranganathan. Our results are separated into three chapters. In Chapter 3, we prove special cases of the Strong Direct Summand Conjecture in…

  3. Physics challenges in the strong interactions

    International Nuclear Information System (INIS)

    Ellis, S.D.

    1992-01-01

    The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders

  4. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D. [Univ. of Washington, Seattle (United States)

    1992-12-31

    The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  5. Theoretical studies of strongly correlated fermions

    Energy Technology Data Exchange (ETDEWEB)

    Logan, D [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Strongly correlated fermions are investigated. An understanding of strongly correlated fermions underpins a diverse range of phenomena such as metal-insulator transitions, high-temperature superconductivity, magnetic impurity problems and the properties of heavy-fermion systems, in all of which local moments play an important role. (author).

  6. The strong reflecting property and Harrington's Principle

    OpenAIRE

    Cheng, Yong

    2015-01-01

    In this paper we characterize the strong reflecting property for $L$-cardinals for all $\\omega_n$, characterize Harrington's Principle $HP(L)$ and its generalization and discuss the relationship between the strong reflecting property for $L$-cardinals and Harrington's Principle $HP(L)$.

  7. Strong Nash Equilibria and the Potential Maimizer

    NARCIS (Netherlands)

    van Megen, F.J.C.; Facchini, G.; Borm, P.E.M.; Tijs, S.H.

    1996-01-01

    A class of non cooperative games characterized by a `congestion e ect' is studied, in which there exists a strong Nash equilibrium, and the set of Nash equilibria, the set of strong Nash equilibria and the set of strategy pro les maximizing the potential function coincide.The structure of the class

  8. Large N baryons, strong coupling theory, quarks

    International Nuclear Information System (INIS)

    Sakita, B.

    1984-01-01

    It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)

  9. The lambda sigma calculus and strong normalization

    DEFF Research Database (Denmark)

    Schack-Nielsen, Anders; Schürmann, Carsten

    Explicit substitution calculi can be classified into several dis- tinct categories depending on whether they are confluent, meta-confluent, strong normalization preserving, strongly normalizing, simulating, fully compositional, and/or local. In this paper we present a variant of the λσ-calculus, ...

  10. Optimization of strong and weak coordinates

    NARCIS (Netherlands)

    Swart, M.; Bickelhaupt, F.M.

    2006-01-01

    We present a new scheme for the geometry optimization of equilibrium and transition state structures that can be used for both strong and weak coordinates. We use a screening function that depends on atom-pair distances to differentiate strong coordinates from weak coordinates. This differentiation

  11. 78 FR 15710 - Strong Sensitizer Guidance

    Science.gov (United States)

    2013-03-12

    ... the supplemental definition of ``strong sensitizer'' found at 16 CFR 1500.3(c)(5). The Commission is proposing to revise the supplemental definition of ``strong sensitizer'' due to advancements in the science...'' definition, assist manufacturers in understanding how CPSC staff would assess whether a substance and/or...

  12. Strong water absorption in the dayside emission spectrum of the planet HD 189733b.

    Science.gov (United States)

    Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

    2008-12-11

    Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources.

  13. Seismic switch for strong motion measurement

    Science.gov (United States)

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  14. Calculation of atmospheric neutrino flux using the interaction model calibrated with atmospheric muon data

    International Nuclear Information System (INIS)

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

    2007-01-01

    Using the 'modified DPMJET-III' model explained in the previous paper [T. Sanuki et al., preceding Article, Phys. Rev. D 75, 043005 (2007).], we calculate the atmospheric neutrino flux. The calculation scheme is almost the same as HKKM04 [M. Honda, T. Kajita, K. Kasahara, and S. Midorikawa, Phys. Rev. D 70, 043008 (2004).], but the usage of the 'virtual detector' is improved to reduce the error due to it. Then we study the uncertainty of the calculated atmospheric neutrino flux summarizing the uncertainties of individual components of the simulation. The uncertainty of K-production in the interaction model is estimated using other interaction models: FLUKA'97 and FRITIOF 7.02, and modifying them so that they also reproduce the atmospheric muon flux data correctly. The uncertainties of the flux ratio and zenith angle dependence of the atmospheric neutrino flux are also studied

  15. Cloud Computing with iPlant Atmosphere.

    Science.gov (United States)

    McKay, Sheldon J; Skidmore, Edwin J; LaRose, Christopher J; Mercer, Andre W; Noutsos, Christos

    2013-10-15

    Cloud Computing refers to distributed computing platforms that use virtualization software to provide easy access to physical computing infrastructure and data storage, typically administered through a Web interface. Cloud-based computing provides access to powerful servers, with specific software and virtual hardware configurations, while eliminating the initial capital cost of expensive computers and reducing the ongoing operating costs of system administration, maintenance contracts, power consumption, and cooling. This eliminates a significant barrier to entry into bioinformatics and high-performance computing for many researchers. This is especially true of free or modestly priced cloud computing services. The iPlant Collaborative offers a free cloud computing service, Atmosphere, which allows users to easily create and use instances on virtual servers preconfigured for their analytical needs. Atmosphere is a self-service, on-demand platform for scientific computing. This unit demonstrates how to set up, access and use cloud computing in Atmosphere. Copyright © 2013 John Wiley & Sons, Inc.

  16. 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.

  17. Atmospheric Composition Change: Climate-Chemistry Interactions

    Science.gov (United States)

    Isaksen, I.S.A.; Granier, C.; Myhre, G.; Bernsten, T. K.; Dalsoren, S. B.; Gauss, S.; Klimont, Z.; Benestad, R.; Bousquet, P.; Collins, W.; hide

    2011-01-01

    Chemically active climate compounds are either primary compounds such as methane (CH4), removed by oxidation in the atmosphere, or secondary compounds such as ozone (O3), sulfate and organic aerosols, formed and removed in the atmosphere. Man-induced climate-chemistry interaction is a two-way process: Emissions of pollutants change the atmospheric composition contributing to climate change through the aforementioned climate components, and climate change, through changes in temperature, dynamics, the hydrological cycle, atmospheric stability, and biosphere-atmosphere interactions, affects the atmospheric composition and oxidation processes in the troposphere. Here we present progress in our understanding of processes of importance for climate-chemistry interactions, and their contributions to changes in atmospheric composition and climate forcing. A key factor is the oxidation potential involving compounds such as O3 and the hydroxyl radical (OH). Reported studies represent both current and future changes. Reported results include new estimates of radiative forcing based on extensive model studies of chemically active climate compounds such as O3, and of particles inducing both direct and indirect effects. Through EU projects such as ACCENT, QUANTIFY, and the AEROCOM project, extensive studies on regional and sector-wise differences in the impact on atmospheric distribution are performed. Studies have shown that land-based emissions have a different effect on climate than ship and aircraft emissions, and different measures are needed to reduce the climate impact. Several areas where climate change can affect the tropospheric oxidation process and the chemical composition are identified. This can take place through enhanced stratospheric-tropospheric exchange of ozone, more frequent periods with stable conditions favouring pollution build up over industrial areas, enhanced temperature-induced biogenic emissions, methane releases from permafrost thawing, and enhanced

  18. Selections from 2017: Discoveries in Titan's Atmosphere

    Science.gov (United States)

    Kohler, Susanna

    2017-12-01

    Editors note:In these last two weeks of 2017, well be looking at a few selections that we havent yet discussed on AAS Nova from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume in January.Carbon Chain Anions and the Growth of Complex Organic Molecules in Titans IonospherePublished July2017Main takeaway:Graphic depicting some of the chemical reactions taking place in Titans atmosphere, leading to the generation of organic haze particles. [ESA]In a recently published study led by Ravi Desai (University College London), scientists used data from the Cassini mission to identify negatively charged molecules known as carbon chain anions in the atmosphere of Saturns largest moon, Titan.Why its interesting:Carbon chain anions are the building blocks ofmore complex molecules, and Titans thick nitrogen and methane atmosphere mightmimic the atmosphere of earlyEarth. This first unambiguous detection of carbon chain anions in a planet-like atmosphere might therefore teach us about the conditions and chemical reactions that eventually led to the development of life on Earth. And ifwe can use Titan to learn about how complex molecules grow from these anion chains, we may be able to identify auniversal pathway towards the ingredients for life.What weve learned so far:Cassini measured fewer and fewer lower-mass anions the deeper in Titans ionosphere that it looked and at the same time,an increase in the number of precursors to larger aerosol molecules further down. This tradeoff strongly suggests that the anions are indeed involved in building up the more complex molecules, seeding their eventual growth into the complex organic haze of Titans lower atmosphere.CitationR. T. Desai et al 2017 ApJL 844 L18. doi:10.3847/2041-8213/aa7851

  19. Electron microscopy of atmospheric particles

    Science.gov (United States)

    Huang, Po-Fu

    Electron microscopy coupled with energy dispersive spectrometry (EM/EDS) is a powerful tool for single particle analysis. However, the accuracy with which atmospheric particle compositions can be quantitatively determined by EDS is often hampered by substrate-particle interactions, volatilization losses in the low pressure microscope chamber, electron beam irradiation and use of inaccurate quantitation factors. A pseudo-analytical solution was derived to calculate the temperature rise due to the dissipation of the electron energy on a particle-substrate system. Evaporative mass loss for a spherical cap-shaped sulfuric acid particle resting on a thin film supported by a TEM grid during electron beam impingement has been studied. Measured volatilization rates were found to be in very good agreement with theoretical predictions. The method proposed can also be used to estimate the vapor pressure of a species by measuring the decay of X-ray intensities. Several types of substrates were studied. We found that silver-coated silicon monoxide substrates give carbon detection limits comparable to commercially available substrates. An advantage of these substrates is that the high thermal conductivity of the silver reduces heating due to electron beam impingement. In addition, exposure of sulfuric acid samples to ammonia overnight substantially reduces sulfur loss in the electron beam. Use of size-dependent k-factors determined from particles of known compositions shows promise for improving the accuracy of atmospheric particle compositions measured by EM/EDS. Knowledge accumulated during the course of this thesis has been used to analyze atmospheric particles (Minneapolis, MN) selected by the TDMA and collected by an aerodynamic focusing impactor. 'Less' hygroscopic particles, which do not grow to any measurable extent when humidified to ~90% relative humidity, included chain agglomerates, spheres, flakes, and irregular shapes. Carbon was the predominant element detected in

  20. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    Science.gov (United States)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  1. Lichens and atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, J H

    1964-09-01

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

  2. Atmospheric Release Advisory Capability

    International Nuclear Information System (INIS)

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

    1983-02-01

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

  3. Outer atmospheric research

    International Nuclear Information System (INIS)

    Anderson, J.L.

    1988-01-01

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

  4. Dual field theory of strong interactions

    International Nuclear Information System (INIS)

    Akers, D.

    1987-01-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant α = 1/137

  5. Strong and superstrong pulsed magnetic fields generation

    CERN Document Server

    Shneerson, German A; Krivosheev, Sergey I

    2014-01-01

    Strong pulsed magnetic fields are important for several fields in physics and engineering, such as power generation and accelerator facilities. Basic aspects of the generation of strong and superstrong pulsed magnetic fields technique are given, including the physics and hydrodynamics of the conductors interacting with the field as well as an account of the significant progress in generation of strong magnetic fields using the magnetic accumulation technique. Results of computer simulations as well as a survey of available field technology are completing the volume.

  6. Semi-strong split domination in graphs

    Directory of Open Access Journals (Sweden)

    Anwar Alwardi

    2014-06-01

    Full Text Available Given a graph $G = (V,E$, a dominating set $D subseteq V$ is called a semi-strong split dominating set of $G$ if $|V setminus D| geq 1$ and the maximum degree of the subgraph induced by $V setminus D$ is 1. The minimum cardinality of a semi-strong split dominating set (SSSDS of G is the semi-strong split domination number of G, denoted $gamma_{sss}(G$. In this work, we introduce the concept and prove several results regarding it.

  7. Atmospherical experiment in Angra I plant for characterizing the effluent transport threw in the atmospheric

    International Nuclear Information System (INIS)

    Silva Lobo, M.A. da; Kronemberger, B.M.E.

    1989-01-01

    Available as short communication only. The Environmental Safety Division of the Nuclear Safety and Fuel Department from FURNAS Electric Station S.A. joint with the National Oceanic and Atmospheric Administration (NOAA), achieved a field experiment for characterizing the atmospheric transport and diffusion in the site complex of Angra I Nuclear Power Plant. The complex topography with the thick vegetation and the neighbour building bring problems for the modelling of the effluent transport and the dispersion. The actual meteorological measure system is automatic and compound with four towers. An intensive atmospheric measure with captive balloon is included, and the collected data shows that the site flux is strongly influenced by the topography and insolation. (C.G.C.). 2 figs

  8. Densification behaviour of UO2 in six different atmospheres

    International Nuclear Information System (INIS)

    Kutty, T.R.G.; Hegde, P.V.; Khan, K.B.; Basak, U.; Pillai, S.N.; Sengupta, A.K.; Jain, G.C.; Majumdar, S.; Kamath, H.S.; Purushotham, D.S.C.

    2002-01-01

    The shrinkage behaviour of UO 2 has been studied using a dilatometer in various atmospheres of Ar, Ar-8%H 2 , vacuum, CO 2 , commercial N 2 and N 2 +1000 ppm of O 2 . The onset of shrinkage occurs at around 300-400 deg. C lower in oxidizing atmospheres such as CO 2 , commercial N 2 and N 2 +1000 ppm O 2 compared to that in reducing or inert atmospheres. Shrinkage behaviour of UO 2 is almost identical in Ar, Ar-8%H 2 and vacuum. The shrinkage in N 2 +1000 ppm O 2 begins at a lower temperature than that in the commercial N 2 . The mechanism of sintering in the reducing, inert and vacuum atmospheres is explained by diffusion of uranium vacancies and that in the oxidizing atmospheres by cluster formation

  9. 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.

  10. Atmospheric tides on Neptune

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  11. Frost formation under different gaseous atmospheres

    International Nuclear Information System (INIS)

    Fukada, Satoshi; Tsuru, Hisanori; Nishikawa, Masabumi

    1995-01-01

    Rates of water frost growth in a vessel with a cooled horizontal plate were experimentally determined under reduced pressure atmospheres of hydrogen, helium, methane and nitrogen. The mass deposited on the cooled surface under each of the atmospheres was almost in proportion to time. The Sherwood number under the condition of no mist formation, Sh 0 , in the atmospheres of methane and nitrogen was in good agreement with Catton's equation for natural convection between horizontal parallel plates. Sh 0 in a hydrogen atmosphere was unity, which corresponds to control by molecular diffusion in the stagnant gas. The tendency of the decrease in Sh due to mist formation could be evaluated well by multiplying Sh 0 by a factor ζ CSM . The ζ CSM value was calculated based on the critical supersaturation model as a function of the two interface temperatures and the total pressure. Frost growth rates under each atmosphere were in proportion to [(T S1 -T W1 )t/(1+1/A S1 )] 0.5 . The proportional constant for hydrogen was greater than that for any other tested gas. Agreement and disagreement of the frost effective thermal conductivity with previous models were discussed. (author)

  12. 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.

  13. Atmospheric benzene and toluene

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  14. DREAMING OF ATMOSPHERES

    International Nuclear Information System (INIS)

    Waldmann, I. P.

    2016-01-01

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

  15. Atmospheric radiation monitor

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  16. Atmospheric radiation monitor

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  17. The Atmospheric Boundary Layer

    Science.gov (United States)

    Garratt, J. R.

    1994-05-01

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

  18. DREAMING OF ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-01

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

  19. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  20. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  2. Temperature variability over the tropical middle atmosphere

    Directory of Open Access Journals (Sweden)

    K. Mohanakumar

    1994-04-01

    Full Text Available A study on the variability of temperature in the tropical middle atmosphere over Thumba (8 32' N, 76 52' E, located at the southern part of India, has been carried out based on rocket observations for a period of 20 years, extending from 1970 to 1990. The rocketsonde-derived mean temperatures over Thumba are corrected prior to 1978 and then compared with the middle atmospheric reference model developed from satellite observations and Solar Mesosphere Explorer (SME satellite data. Temperature variability at every 1 km interval in the 25-75 km region was analysed. The tropical stratosphere is found to be highly stable, whereas considerable variability is noted in the middle mesosphere. The effect of seasonal cycle is least in the lower stratosphere. Annual and semi-annual oscillations in temperature are the primary oscillations in the tropical middle atmosphere. Annual temperature oscillations are dominant in the mesosphere and semi-annual oscillations are strong in the stratosphere. The stratopause region is noted to be the part of the middle atmosphere least sensitive to the changes in solar activity and long-term variability.

  3. Strong-force theorists scoop Noble Prize

    CERN Multimedia

    Durrani, Matin

    2004-01-01

    Three US theorists have shared the 2004 Nobel Prize in Physics "for the discovery of asymptotic freedom in the theory of the strong interaction". Their theoretical work explains why quarks behave almost as free particles at high energies (½ page)

  4. Strong-coupling theory of superconductivity

    International Nuclear Information System (INIS)

    Rainer, D.; Sauls, J.A.

    1995-01-01

    The electronic properties of correlated metals with a strong electron-phonon coupling may be understood in terms of a combination of Landau''s Fermi liquid theory and the strong-coupling theory of Migdal and Eliashberg. In these lecture notes we discuss the microscopic foundations of this phenomenological Fermi-liquid model of correlated, strong-coupling metals. We formulate the basic equations of the model, which are quasiclassical transport equations that describe both equilibrium and non-equilibrium phenomena for the normal and superconducting states of a metal. Our emphasis is on superconductors close to equilibrium, for which we derive the general linear response theory. As an application we calculate the dynamical conductivity of strong-coupling superconductors. (author)

  5. Nuclear physics from strong coupling QCD

    CERN Document Server

    Fromm, Michael

    2009-01-01

    The strong coupling limit (beta_gauge = 0) of QCD offers a number of remarkable research possibilities, of course at the price of large lattice artifacts. Here, we determine the complete phase diagram as a function of temperature T and baryon chemical potential mu_B, for one flavor of staggered fermions in the chiral limit, with emphasis on the determination of a tricritical point and on the T ~ 0 transition to nuclear matter. The latter is known to happen for mu_B substantially below the baryon mass, indicating strong nuclear interactions in QCD at infinite gauge coupling. This leads us to studying the properties of nuclear matter from first principles. We determine the nucleon-nucleon potential in the strong coupling limit, as well as masses m_A of nuclei as a function of their atomic number A. Finally, we clarify the origin of nuclear interactions at strong coupling, which turns out to be a steric effect.

  6. Modeling and synthesis of strong ground motion

    Indian Academy of Sciences (India)

    There have been many developments in modeling techniques, and ... damage life and property in a city or region. How- ... quake of 26 January 2001 as a case study. 2. ...... quake derived from a dense strong-motion network; Bull. Seismol.

  7. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  8. Physics challenges in the strong interactions

    International Nuclear Information System (INIS)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders

  9. Strong interaction effects in hadronic atoms

    International Nuclear Information System (INIS)

    Kaufmann, W.B.

    1977-01-01

    The WKB method is applied to the calculation of strong interaction-induced level widths and shifts of hadronic atoms. The calculation, while elementary enough for undergraduate quantum mechanics students, gives a good account of kaonic and antiprotonic atom data

  10. Perturbation of an exact strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1982-10-01

    Perturbations of an exact strong gravity solution are investigated. It is shown, by using the new multipole expansions previously presented, that this exact and static spherically symmetric solution is stable under odd parity perturbations. (author)

  11. Calculating hadronic properties in strong QCD

    International Nuclear Information System (INIS)

    Pennington, M.R.

    1996-01-01

    This talk gives a brief review of the progress that has been made in calculating the properties of hadrons in strong QCD. In keeping with this meeting I will concentrate on those properties that can be studied with electromagnetic probes. Though perturbative QCD is highly successful, it only applies in a limited kinematic regime, where hard scattering occur, and the quarks move in the interaction region as if they are free, pointlike objects. However, the bulk of strong interactions are governed by the long distance regime, where the strong interaction is strong. It is this regime of length scales of the order of a Fermi, that determines the spectrum of light hadrons and their properties. The calculation of these properties requires an understanding of non-perturbative QCD, of confinement and chiral symmetry breaking. (author)

  12. The Charm and Beauty of Strong Interactions

    Science.gov (United States)

    El-Bennich, Bruno

    2018-01-01

    We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.

  13. Strong impacts on aerosol indirect effects from historical oxidant changes

    Science.gov (United States)

    Hafsahl Karset, Inger Helene; Koren Berntsen, Terje; Storelvmo, Trude; Alterskjær, Kari; Grini, Alf; Olivié, Dirk; Kirkevåg, Alf; Seland, Øyvind; Iversen, Trond; Schulz, Michael

    2018-06-01

    Uncertainties in effective radiative forcings through aerosol-cloud interactions (ERFaci, also called aerosol indirect effects) contribute strongly to the uncertainty in the total preindustrial-to-present-day anthropogenic forcing. Some forcing estimates of the total aerosol indirect effect are so negative that they even offset the greenhouse gas forcing. This study highlights the role of oxidants in modeling of preindustrial-to-present-day aerosol indirect effects. We argue that the aerosol precursor gases should be exposed to oxidants of its era to get a more correct representation of secondary aerosol formation. Our model simulations show that the total aerosol indirect effect changes from -1.32 to -1.07 W m-2 when the precursor gases in the preindustrial simulation are exposed to preindustrial instead of present-day oxidants. This happens because of a brightening of the clouds in the preindustrial simulation, mainly due to large changes in the nitrate radical (NO3). The weaker oxidative power of the preindustrial atmosphere extends the lifetime of the precursor gases, enabling them to be transported higher up in the atmosphere and towards more remote areas where the susceptibility of the cloud albedo to aerosol changes is high. The oxidation changes also shift the importance of different chemical reactions and produce more condensate, thus increasing the size of the aerosols and making it easier for them to activate as cloud condensation nuclei.

  14. Strong impacts on aerosol indirect effects from historical oxidant changes

    Directory of Open Access Journals (Sweden)

    I. H. H. Karset

    2018-06-01

    Full Text Available Uncertainties in effective radiative forcings through aerosol–cloud interactions (ERFaci, also called aerosol indirect effects contribute strongly to the uncertainty in the total preindustrial-to-present-day anthropogenic forcing. Some forcing estimates of the total aerosol indirect effect are so negative that they even offset the greenhouse gas forcing. This study highlights the role of oxidants in modeling of preindustrial-to-present-day aerosol indirect effects. We argue that the aerosol precursor gases should be exposed to oxidants of its era to get a more correct representation of secondary aerosol formation. Our model simulations show that the total aerosol indirect effect changes from −1.32 to −1.07 W m−2 when the precursor gases in the preindustrial simulation are exposed to preindustrial instead of present-day oxidants. This happens because of a brightening of the clouds in the preindustrial simulation, mainly due to large changes in the nitrate radical (NO3. The weaker oxidative power of the preindustrial atmosphere extends the lifetime of the precursor gases, enabling them to be transported higher up in the atmosphere and towards more remote areas where the susceptibility of the cloud albedo to aerosol changes is high. The oxidation changes also shift the importance of different chemical reactions and produce more condensate, thus increasing the size of the aerosols and making it easier for them to activate as cloud condensation nuclei.

  15. Atmospheric chemistry: Description of the area of performance and a working plan

    Science.gov (United States)

    Kirchhoff, Volker W. J. H.

    1986-11-01

    INPE's program in Atmospheric Chemistry Research is described. Research in this area is concerned with atmospheric gases and their chemical reactions, production and loss rates, and their interactions with the biosphere. Atmospheric chemistry includes concepts in Physics, Chemistry, Meteorology, and Biology, which gives it a strong interdisciplinary character. The interaction of some of the atmospheric gases with the biosphere, such as ozone, is very strong and direct. Studying atmospheric chemistry is, therefore, of direct interest to man and the quality of life. Details are described to define the objectives of study, in particular those of our research program at INPE. A working plan is proposed in order to reach the defined goals. Owing to the large anthropogenic interference in the balance of the natural atmosphere it is anticipated that a better understanding of Atmospheric Chemistry will be the great scientific challenge of the next decade.

  16. Intermittency in Hall-magnetohydrodynamics with a strong guide field

    OpenAIRE

    Imazio, P. Rodriguez; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

    2013-01-01

    We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure funct...

  17. The persistent and pernicious myth of the early CO2-N2 atmospheres of terrestrial planets

    Science.gov (United States)

    Shaw, G. H.

    2009-12-01

    don’t get life. Third, solutions invoking high atmospheric CO2 as the answer to the faint young sun problem encounter exactly the same problems associated with prompt degassing of CO2. Fourth, the carbon isotope record, in which early carbonaceous deposits show signs of photosynthetic fractionation of carbon are problematical if most of the primary surface and near-surface carbon was CO2. Finally, the delay in oxidation of Earth’s surface following oxygenic photosynthesis is problematical if early photosynthesizers had a vast CO2 source from early degassing. Given an abundant food supply, what prevented early cyanobacteria from rapidly oxidizing the surface? Although discovery of CO2-rich atmospheres on Venus and Mars seem to support CO2 as the primary surface carbon reservoir, these atmospheres are the result of atmospheric evolution, particularly loss of H to space. ALL of these problems disappear with early degassing of reduced gases such as CH4 and NH3. Considerations of meteoritic compositions, accretionary processes, and early atmosphere/hydrosphere chemical processing all support reduced gases as dominant in the early atmospheres of the terrestrial planets. The time has come to revert to any earlier idea of strongly reducing conditions on early terrestrial planet surfaces, followed by long-term evolutionary trends toward oxidation.

  18. Reducing Resistance

    DEFF Research Database (Denmark)

    Lindell, Johanna

    care may influence decisions on antibiotic use. Based on video-and audio recordings of physician-patient consultations it is investigated how treatment recommendations are presented, can be changed, are forecast and explained, and finally, how they seemingly meet resistance and how this resistance......Antibiotic resistance is a growing public health problem both nationally and internationally, and efficient strategies are needed to reduce unnecessary use. This dissertation presents four research studies, which examine how communication between general practitioners and patients in Danish primary...... is responded to.The first study in the dissertation suggests that treatment recommendations on antibiotics are often done in a way that encourages patient acceptance. In extension of this, the second study of the dissertation examines a case, where acceptance of such a recommendation is changed into a shared...

  19. Interaction of strong electromagnetic fields with atoms

    International Nuclear Information System (INIS)

    Brandi, H.S.; Davidovich, L.; Zagury, N.

    1982-06-01

    Several non-linear processes involvoing the interaction of atoms with strong laser fields are discussed, with particular emphasis on the ionization problem. Non-perturbative methods which have been proposed to tackle this problem are analysed, and shown to correspond to an expansion in the intra-atomic potential. The relation between tunneling and multiphoton absorption as ionization mechanisms, and the generalization of Einstein's photoelectric equation to the strong-field case are discussed. (Author) [pt

  20. Building strong brands – does it matter?

    OpenAIRE

    Aure, Kristin Gaaseide; Nervik, Kristine Dybvik

    2014-01-01

    Brand equity has proven, through several decades of research, to be a primary source of competitive advantage and future earnings (Yoo & Donthu, 2001). Building strong brands has therefore become a priority for many organizations, with the presumption that building strong brands yields these advantages (Yasin et al., 2007). A quantitative survey was conducted at Sunnmøre in Norway in order to answer the two developed research questions. - Does the brand equity dimensions; brand...

  1. Algebra of strong and electroweak interactions

    International Nuclear Information System (INIS)

    Bolokhov, S.V.; Vladimirov, Yu.S.

    2004-01-01

    The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru

  2. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  3. Nonlinear wave collapse and strong turbulence

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1997-01-01

    The theory and applications of wave self-focusing, collapse, and strongly nonlinear wave turbulence are reviewed. In the last decade, the theory of these phenomena and experimental realizations have progressed rapidly. Various nonlinear wave systems are discussed, but the simplest case of collapse and strong turbulence of Langmuir waves in an unmagnetized plasma is primarily used in explaining the theory and illustrating the main ideas. First, an overview of the basic physics of linear waves and nonlinear wave-wave interactions is given from an introductory perspective. Wave-wave processes are then considered in more detail. Next, an introductory overview of the physics of wave collapse and strong turbulence is provided, followed by a more detailed theoretical treatment. Later sections cover numerical simulations of Langmuir collapse and strong turbulence and experimental applications to space, ionospheric, and laboratory plasmas, including laser-plasma and beam-plasma interactions. Generalizations to self-focusing, collapse, and strong turbulence of waves in other systems are also discussed, including nonlinear optics, solid-state systems, magnetized auroral and astrophysical plasmas, and deep-water waves. The review ends with a summary of the main ideas of wave collapse and strong-turbulence theory, a collection of open questions in the field, and a brief discussion of possible future research directions. copyright 1997 The American Physical Society

  4. Atmospheric activity in red dwarf stars

    International Nuclear Information System (INIS)

    Pettersen, B.R.

    1986-01-01

    Active and inactive stars of similar mass and luminosity have similar physical conditions in their photospheres, outside of magnetically disturbed regions. Such field structures give rise to stellar activity, which manifests itself at all heights of the atmosphere. Observations of uneven distributions of flux across the stellar disc have led to the disovery of photospheric starspots, chromospheric plage areas, and coronal holes. Localized transient behavior has been identified in both thermal and non-thermal sources, such as flares, shock waves and particle acceleration. The common element to all active regions is the presence of strong magnetic field structures connecting the violently turbulent deep layers in the convection zones of stars with the tenuous outer atmospheres. Transport and dissipation of energy into the chromospheric and coronal regions are still much debated topics

  5. Heat transfer in the atmosphere

    NARCIS (Netherlands)

    Oerlemans, J.

    1982-01-01

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

  6. Atmospheric tritium. Measurement and application

    International Nuclear Information System (INIS)

    Frejaville, Gerard

    1967-02-01

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

  7. Structural modifications under reactive atmosphere of cobalt catalysts; Modifications structurales sous atmospheres reactionnelles de catalyseurs a base de cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Ducreux, O.

    1999-11-23

    The purpose of this work was to develop in situ methods under reactive dynamic conditions (XRD and Fourier transform infrared spectroscopy) to describe the active phase structure in order to understand Fischer-Tropsch catalyst behaviour and improve the natural gas conversion process performance. Experiments were designed to correlate structural modifications with catalytic results. The effect of ruthenium used as a promoter has also been studied. The impregnation process increases cobalt-support interaction. The presence of ruthenium promoter reduces this effect. Interactions between Co{sub 3}O{sub 4} oxide and support play an important role in the reducibility of cobalt and in the resulting metal structure. This in turn strongly influences the catalytic behaviour. Our results show a close correlation between structure modification and reactivity in the systems studied. Cobalt metal and CO can react to form a carbide Co{sub 2}C under conditions close to those of the Fischer-Tropsch synthesis. This carbide formation seems to be related to a deactivation process. The presence of interstitial carbon formed by dissociation of CO is proposed as a key to understanding the mechanism of the Fischer-Tropsch reaction. A specific catalyst activation treatment was developed to increase the catalytic activity. This work permits correlation of materials structure with their chemical properties and demonstrates the contribution of in situ physico-chemical characterisation methods to describe solids under reactive atmosphere. (author)

  8. The extended reciprocity: Strong belief outperforms persistence.

    Science.gov (United States)

    Kurokawa, Shun

    2017-05-21

    The existence of cooperation is a mysterious phenomenon and demands explanation, and direct reciprocity is one key potential explanation for the evolution of cooperation. Direct reciprocity allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior. Here, relevant to direct reciprocity is information deficiency. When the opponent's last move is unknown, how should players behave? One possibility is to choose cooperation with some default probability without using any further information. In fact, our previous paper (Kurokawa, 2016a) examined this strategy. However, there might be beneficial information other than the opponent's last move. A subsequent study of ours (Kurokawa, 2017) examined the strategy which uses the own last move when the opponent's last move is unknown, and revealed that referring to the own move and trying to imitate it when information is absent is beneficial. Is there any other beneficial information else? How about strong belief (i.e., have infinite memory and believe that the opponent's behavior is unchanged)? Here, we examine the evolution of strategies with strong belief. Analyzing the repeated prisoner's dilemma game and using evolutionarily stable strategy (ESS) analysis against an invasion by unconditional defectors, we find the strategy with strong belief is more likely to evolve than the strategy which does not use information other than the opponent player's last move and more likely to evolve than the strategy which uses not only the opponent player's last move but also the own last move. Strong belief produces the extended reciprocity and facilitates the evolution of cooperation. Additionally, we consider the two strategies game between strategies with strong belief and any strategy, and we consider the four strategies game in which unconditional cooperators, unconditional defectors, pessimistic reciprocators with strong belief, and optimistic reciprocators with

  9. Reducing costs by reducing size

    International Nuclear Information System (INIS)

    Hayns, M.R.; Shepherd, J.

    1991-01-01

    The present paper discusses briefly the many factors, including capital cost, which have to be taken into account in determining whether a series of power stations based on a small nuclear plant can be competitive with a series based on traditional large unit sizes giving the guaranteed level of supply. The 320 MWe UK/US Safe Integral Reactor is described as a good example of how the factors discussed can be beneficially incorporated into a design using proven technology. Finally it goes on to illustrate how the overall costs of a generating system can indeed by reduced by use of the 320 MWe Safe Integral Reactor rather than conventional units of around 1200 MWe. (author). 9 figs

  10. Titan's hydrodynamically escaping atmosphere

    Science.gov (United States)

    Strobel, Darrell F.

    2008-02-01

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

  11. What controls the atmospheric methane seasonal variability over India?

    KAUST Repository

    Guha, Tania; Tiwari, Yogesh K.; Valsala, Vinu; Lin, Xin; Ramonet, Michel; Mahajan, Anoop; Datye, Amey; Kumar, K. Ravi

    2017-01-01

    Atmospheric CH4 observations from two ground-based stations within Indian subcontinent, namely, Sinhagad (SNG) and Cape Rama station (CRI) showed a strong seasonality with a minima (∼1800 ± 20 ppb) during southwest monsoon (SWM; i.e. June–September, JJAS) and a maxima (2000 ± 30 ppb) during northeast monsoon (NEM i.e. December–February, DJF) with a peak-to-peak seasonality close to 200 ppb. The Indian summer (winter) monsoon is characterized with strong southwesterly (northeasterly) winds of oceanic origin at the surface level and strong easterly (westerly) jet streams aloft. The monsoon dynamics has pronounced impact on CH4 variability over India and is analyzed with winds, Lagrangian trajectories, and 3-dimentional distributions of CH4 simulated by a general circulation model. The model simulations suggest a consistent annual vertical structure (mean and sub-seasonal uncertainty) of CH4 over India with a stark contrast in concentration from summer to winter at surface levels (below 750 mb) in confirmation with what is identified by the ground-based observations. During SWM (NEM) the air with comparatively lower (higher) CH4 concentrations from southern (northern) hemisphere reduces the CH4 over India by 1814 ± 26 ppb (enhances by 1950 ± 51 ppb). The contribution of local fluxes to this seasonality appears to be albeit weak as the synthesized CH4 fluxes (from EDGAR dataset) of the Indian peninsula itself show a peak in summer and a dip in winter. Similar property of CH4 is also common to nearby oceanic region (i.e. over Arabian Sea, 1765 ± 10 ppb during summer) suggesting the role of monsoon dynamics as the controlling factor. Further the mixing and convection carries the CH4 to the upper atmosphere and advect inward or outward aloft according the seasonal monsoon dynamics.

  12. What controls the atmospheric methane seasonal variability over India?

    KAUST Repository

    Guha, Tania

    2017-11-28

    Atmospheric CH4 observations from two ground-based stations within Indian subcontinent, namely, Sinhagad (SNG) and Cape Rama station (CRI) showed a strong seasonality with a minima (∼1800 ± 20 ppb) during southwest monsoon (SWM; i.e. June–September, JJAS) and a maxima (2000 ± 30 ppb) during northeast monsoon (NEM i.e. December–February, DJF) with a peak-to-peak seasonality close to 200 ppb. The Indian summer (winter) monsoon is characterized with strong southwesterly (northeasterly) winds of oceanic origin at the surface level and strong easterly (westerly) jet streams aloft. The monsoon dynamics has pronounced impact on CH4 variability over India and is analyzed with winds, Lagrangian trajectories, and 3-dimentional distributions of CH4 simulated by a general circulation model. The model simulations suggest a consistent annual vertical structure (mean and sub-seasonal uncertainty) of CH4 over India with a stark contrast in concentration from summer to winter at surface levels (below 750 mb) in confirmation with what is identified by the ground-based observations. During SWM (NEM) the air with comparatively lower (higher) CH4 concentrations from southern (northern) hemisphere reduces the CH4 over India by 1814 ± 26 ppb (enhances by 1950 ± 51 ppb). The contribution of local fluxes to this seasonality appears to be albeit weak as the synthesized CH4 fluxes (from EDGAR dataset) of the Indian peninsula itself show a peak in summer and a dip in winter. Similar property of CH4 is also common to nearby oceanic region (i.e. over Arabian Sea, 1765 ± 10 ppb during summer) suggesting the role of monsoon dynamics as the controlling factor. Further the mixing and convection carries the CH4 to the upper atmosphere and advect inward or outward aloft according the seasonal monsoon dynamics.

  13. Atmospheric natural radioactivity outdoors

    International Nuclear Information System (INIS)

    Renoux, A.

    1985-01-01

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

  14. Atmospheres of central stars

    International Nuclear Information System (INIS)

    Hummer, D.G.

    1978-01-01

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

  15. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

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

    1990-02-01

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

  16. Rectenna related atmospheric effects

    Science.gov (United States)

    Lee, J.

    1980-01-01

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

  17. Analysis of the atmospheric upward radiation in low latitude area

    Science.gov (United States)

    Li, Haiying; Wu, Zhensen; Lin, Leke; Lu, Changsheng

    2016-10-01

    Remote sensing using THz wave has irreplaceable advantage comparing to the microwave and the infrared waves, and study on the THz remote sensing become more and more popular in recent years. The major applications of the remote sensing in THz wavelengths are the retrieval of the atmospheric parameters and the microphysical information of the ice cloud. The remote sensing of the atmosphere is based on the radiation of THz wave along the earth-space path of which the most significant part is the upward radiation of the atmosphere. The upward radiation of the atmosphere in sunny day in the low latitude area is computed and analyzed in this paper. The absorption of THz wave by the atmosphere is calculated using the formulations illustrated in the Recommendation ITU-R P.676 to save machine hour, the frequency range is then restricted below 1THz. The frequencies used for the retrieval of atmospheric parameters such as temperature and water content are usually a few hundred GHz, at the lower end of THz wavelengths, so this frequency range is sufficient. The radiation contribution of every atmospheric layer for typical frequencies such as absorption window frequencies and peak frequencies are analyzed. Results show that at frequencies which absorption is severe, information about lower atmosphere cannot reach the receiver onboard a satellite or other high platforms due to the strong absorption along the path.

  18. Frontiers in Atmospheric Chemistry Modelling

    Science.gov (United States)

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

    2013-04-01

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

  19. Advanced Atmospheric Ensemble Modeling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Chiswell, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kurzeja, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Maze, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Viner, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Werth, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-29

    Ensemble modeling (EM), the creation of multiple atmospheric simulations for a given time period, has become an essential tool for characterizing uncertainties in model predictions. We explore two novel ensemble modeling techniques: (1) perturbation of model parameters (Adaptive Programming, AP), and (2) data assimilation (Ensemble Kalman Filter, EnKF). The current research is an extension to work from last year and examines transport on a small spatial scale (<100 km) in complex terrain, for more rigorous testing of the ensemble technique. Two different release cases were studied, a coastal release (SF6) and an inland release (Freon) which consisted of two release times. Observations of tracer concentration and meteorology are used to judge the ensemble results. In addition, adaptive grid techniques have been developed to reduce required computing resources for transport calculations. Using a 20- member ensemble, the standard approach generated downwind transport that was quantitatively good for both releases; however, the EnKF method produced additional improvement for the coastal release where the spatial and temporal differences due to interior valley heating lead to the inland movement of the plume. The AP technique showed improvements for both release cases, with more improvement shown in the inland release. This research demonstrated that transport accuracy can be improved when models are adapted to a particular location/time or when important local data is assimilated into the simulation and enhances SRNL’s capability in atmospheric transport modeling in support of its current customer base and local site missions, as well as our ability to attract new customers within the intelligence community.

  20. Special issue: diagnostics of atmospheric pressure microplasmas

    Science.gov (United States)

    Bruggeman, Peter; Czarnetzki, Uwe; Tachibana, Kunihide

    2013-11-01

    In recent decades, a strong revival of non-equilibrium atmospheric pressure plasma studies has developed in the form of microplasmas. Microplasmas have typical scales of 1 mm or less and offer a very exciting research direction in the field of plasma science and technology as the discharge physics can be considerably different due to high collisionality and the importance of plasma-surface interaction. These high-pressure small-scale plasmas have a diverse range of physical and chemical properties. This diversity coincides with various applications including light/UV sources [1], material processing [2], chemical analysis [3], material synthesis [4], electromagnetics [5], combustion [6] and even medicine [7]. At atmospheric pressure, large scale plasmas have the tendency to become unstable due to the high collision rates leading to enhanced heating and ionization compared to their low-pressure counterparts. As low-pressure plasmas typically operate in reactors with sizes of tens of centimetres, scaling up the pressure to atmospheric pressure the size of the plasma reduces to typical sizes below 1 mm. A natural approach of stabilizing atmospheric pressure plasmas is thus the use of microelectrode geometries. Traditionally microplasmas have been produced in confined geometries which allow one to stabilize dc excited discharges. This stabilization is intrinsically connected to the large surface-to-volume ratio which enhances heat transfer and losses of charged and excited species to the walls. Currently challenging boundaries are pushed by producing microcavity geometries with dimensions of the order of 1 µm [8]. The subject of this special issue, diagnostics of microplasmas, is motivated by the many challenges in microplasma diagnostics in view of the complex chemistry and strong spatial (and even temporal) gradients of species densities and plasma properties. Atmospheric pressure plasmas have a very long history dating back more than 100 years, with early work of

  1. Measuring mixing efficiency in experiments of strongly stratified turbulence

    Science.gov (United States)

    Augier, P.; Campagne, A.; Valran, T.; Calpe Linares, M.; Mohanan, A. V.; Micard, D.; Viboud, S.; Segalini, A.; Mordant, N.; Sommeria, J.; Lindborg, E.

    2017-12-01

    Oceanic and atmospheric models need better parameterization of the mixing efficiency. Therefore, we need to measure this quantity for flows representative of geophysical flows, both in terms of types of flows (with vortices and/or waves) and of dynamical regimes. In order to reach sufficiently large Reynolds number for strongly stratified flows, experiments for which salt is used to produce the stratification have to be carried out in a large rotating platform of at least 10-meter diameter.We present new experiments done in summer 2017 to study experimentally strongly stratified turbulence and mixing efficiency in the Coriolis platform. The flow is forced by a slow periodic movement of an array of large vertical or horizontal cylinders. The velocity field is measured by 3D-2C scanned horizontal particles image velocimetry (PIV) and 2D vertical PIV. Six density-temperature probes are used to measure vertical and horizontal profiles and signals at fixed positions.We will show how we rely heavily on open-science methods for this study. Our new results on the mixing efficiency will be presented and discussed in terms of mixing parameterization.

  2. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  3. Coherent Vortices in Strongly Coupled Liquids

    International Nuclear Information System (INIS)

    Ashwin, J.; Ganesh, R.

    2011-01-01

    Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using ''first principles'' molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

  4. Coherent Vortices in Strongly Coupled Liquids

    Science.gov (United States)

    Ashwin, J.; Ganesh, R.

    2011-04-01

    Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using “first principles” molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

  5. Strong Coupling between Plasmons and Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Joel Bellessa

    2014-05-01

    Full Text Available In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed.

  6. Institutionalizing Strong Sustainability: A Rawlsian Perspective

    Directory of Open Access Journals (Sweden)

    Konrad Ott

    2014-02-01

    Full Text Available The article aims to provide some ethical orientation on how sustainability might be actualized by institutions. Since institutionalization is about rules and organization, it presupposes ideas and concepts by which institutions can be substantiated. After outlining terminology, the article deals with underlying ethical and conceptual problems which are highly relevant for any suggestions concerning institutionalization. These problems are: (a the ethical scope of the sustainability perspective (natural capital, poverty, sentient animals, (b the theory of justice on which ideas about sustainability are built (capability approach, Rawlsianism, and (c the favored concept of sustainability (weak, intermediate, and strong sustainability. These problems are analyzed in turn. As a result, a Rawlsian concept of rule-based strong sustainability is proposed. The specific problems of institutionalization are addressed by applying Rawls’s concept of branches. The article concludes with arguments in favor of three transnational duties which hold for states that have adopted Rawlsian strong sustainability.

  7. A theory of the strong interactions

    International Nuclear Information System (INIS)

    Gross, D.J.

    1979-01-01

    The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)

  8. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

    Electronic structure and physical properties of strongly correlated materials containing elements with partially filled 3d, 4d, 4f and 5f electronic shells is analyzed by Dynamical Mean-Field Theory (DMFT). DMFT is the most universal and effective tool used for the theoretical investigation of electronic states with strong correlation effects. In the present book the basics of the method are given and its application to various material classes is shown. The book is aimed at a broad readership: theoretical physicists and experimentalists studying strongly correlated systems. It also serves as a handbook for students and all those who want to be acquainted with fast developing filed of condensed matter physics.

  9. Strongly interacting matter in magnetic fields

    CERN Document Server

    Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

    2013-01-01

    The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...

  10. Forcing of global ocean models using an atmospheric boundary layer model: assessing consequences for the simulation of the AMOC

    Science.gov (United States)

    Abel, Rafael; Boening, Claus

    2015-04-01

    Current practice in the atmospheric forcing of ocean model simulations can lead to unphysical behaviours. The problem lies in the bulk formulation of the turbulent air-sea fluxes in conjunction with a prescribed, and unresponsive, atmospheric state as given, e.g., by reanalysis products. This forcing formulation corresponds to assuming an atmosphere with infinite heat capacity, and effectively damps SST anomalies even on basin scales. It thus curtails an important negative feedback between meridional ocean heat transport and SST in the North Atlantic, rendering simulations of the AMOC in such models excessively sensitive to details in the freshwater fluxes. As a consequence, such simulations are known for spurious drift behaviors which can only partially controlled by introducing some (and sometimes strong) unphysical restoring of sea surface salinity. There have been several suggestions during the last 20 years for at least partially alleviating the problem by including some simplified model of the atmospheric boundary layer (AML) which allows a feedback of SST anomalies on the near-surface air temperature and humidity needed to calculate the surface fluxes. We here present simulations with a simple, only thermally active AML formulation (based on the 'CheapAML' proposed by Deremble et al., 2013) implemented in a global model configuration based on NEMO (ORCA05). In a suite of experiments building on the CORE-bulk forcing methodology, we examine some general features of the AML-solutions (in which only the winds are prescribed) in comparison to solutions with a prescribed atmosperic state. The focus is on the North Atlantic, where we find that the adaptation of the atmospheric temperature the simulated ocean state can lead to strong local modifications in the surface heat fluxes in frontal regions (e.g., the 'Northwest Corner'). We particularly assess the potential of the AML-forcing concept for obtaining AMOC-simulations with reduced spurious drift, without

  11. Refining multi-model projections of temperature extremes by evaluation against land-atmosphere coupling diagnostics

    Science.gov (United States)

    Sippel, Sebastian; Zscheischler, Jakob; Mahecha, Miguel D.; Orth, Rene; Reichstein, Markus; Vogel, Martha; Seneviratne, Sonia I.

    2017-05-01

    The Earth's land surface and the atmosphere are strongly interlinked through the exchange of energy and matter. This coupled behaviour causes various land-atmosphere feedbacks, and an insufficient understanding of these feedbacks contributes to uncertain global climate model projections. For example, a crucial role of the land surface in exacerbating summer heat waves in midlatitude regions has been identified empirically for high-impact heat waves, but individual climate models differ widely in their respective representation of land-atmosphere coupling. Here, we compile an ensemble of 54 combinations of observations-based temperature (T) and evapotranspiration (ET) benchmarking datasets and investigate coincidences of T anomalies with ET anomalies as a proxy for land-atmosphere interactions during periods of anomalously warm temperatures. First, we demonstrate that a large fraction of state-of-the-art climate models from the Coupled Model Intercomparison Project (CMIP5) archive produces systematically too frequent coincidences of high T anomalies with negative ET anomalies in midlatitude regions during the warm season and in several tropical regions year-round. These coincidences (high T, low ET) are closely related to the representation of temperature variability and extremes across the multi-model ensemble. Second, we derive a land-coupling constraint based on the spread of the T-ET datasets and consequently retain only a subset of CMIP5 models that produce a land-coupling behaviour that is compatible with these benchmark estimates. The constrained multi-model simulations exhibit more realistic temperature extremes of reduced magnitude in present climate in regions where models show substantial spread in T-ET coupling, i.e. biases in the model ensemble are consistently reduced. Also the multi-model simulations for the coming decades display decreased absolute temperature extremes in the constrained ensemble. On the other hand, the differences between projected

  12. Refining multi-model projections of temperature extremes by evaluation against land–atmosphere coupling diagnostics

    Directory of Open Access Journals (Sweden)

    S. Sippel

    2017-05-01

    Full Text Available The Earth's land surface and the atmosphere are strongly interlinked through the exchange of energy and matter. This coupled behaviour causes various land–atmosphere feedbacks, and an insufficient understanding of these feedbacks contributes to uncertain global climate model projections. For example, a crucial role of the land surface in exacerbating summer heat waves in midlatitude regions has been identified empirically for high-impact heat waves, but individual climate models differ widely in their respective representation of land–atmosphere coupling. Here, we compile an ensemble of 54 combinations of observations-based temperature (T and evapotranspiration (ET benchmarking datasets and investigate coincidences of T anomalies with ET anomalies as a proxy for land–atmosphere interactions during periods of anomalously warm temperatures. First, we demonstrate that a large fraction of state-of-the-art climate models from the Coupled Model Intercomparison Project (CMIP5 archive produces systematically too frequent coincidences of high T anomalies with negative ET anomalies in midlatitude regions during the warm season and in several tropical regions year-round. These coincidences (high T, low ET are closely related to the representation of temperature variability and extremes across the multi-model ensemble. Second, we derive a land-coupling constraint based on the spread of the T–ET datasets and consequently retain only a subset of CMIP5 models that produce a land-coupling behaviour that is compatible with these benchmark estimates. The constrained multi-model simulations exhibit more realistic temperature extremes of reduced magnitude in present climate in regions where models show substantial spread in T–ET coupling, i.e. biases in the model ensemble are consistently reduced. Also the multi-model simulations for the coming decades display decreased absolute temperature extremes in the constrained ensemble. On the other hand

  13. Frictional Coulomb drag in strong magnetic fields

    DEFF Research Database (Denmark)

    Bønsager, Martin Christian; Flensberg, Karsten; Hu, Ben Yu-Kuang

    1997-01-01

    A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21...

  14. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  15. Strong WW scattering at photon linear colliders

    International Nuclear Information System (INIS)

    Berger, M.S.

    1994-06-01

    We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process γγ → ZZ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the Z bosons to enhance the signal relative to the background of transversely polarized ZZ pairs. We find that the background overwhelms the signal unless there are strong resonant effects, as for instance from a technicolor analogue of the hadronic f 2 (1270) meson

  16. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

  17. Universal behavior of strongly correlated Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Shaginyan, Vasilii R [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation); Amusia, M Ya [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation); Popov, Konstantin G [Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar (Russian Federation)

    2007-06-30

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T{sub c} superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  18. Universal behavior of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Shaginyan, Vasilii R; Amusia, M Ya; Popov, Konstantin G

    2007-01-01

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T c superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  19. De Sitter vacua of strongly interacting QFT

    Energy Technology Data Exchange (ETDEWEB)

    Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)

    2017-03-22

    We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.

  20. Optical spectral weight anomalies and strong correlation

    International Nuclear Information System (INIS)

    Toschi, A.; Capone, M.; Ortolani, M.; Calvani, P.; Lupi, S.; Castellani, C.

    2007-01-01

    The anomalous behavior observed in the optical spectral weight (W) of the cuprates provides valuable information about the physics of these compounds. Both the doping and the temperature dependences of W are hardly explained through conventional estimates based on the f-sum rule. By computing the optical conductivity of the doped Hubbard model with the Dynamical Mean Field Theory, we point out that the strong correlation plays a key role in determining the basic features of the observed anomalies: the proximity to a Mott insulating phase accounts simultaneously for the strong temperature dependence of W and for its zero temperature value

  1. Strong cosmic censorship in de Sitter space

    Science.gov (United States)

    Dias, Oscar J. C.; Eperon, Felicity C.; Reall, Harvey S.; Santos, Jorge E.

    2018-05-01

    Recent work indicates that the strong cosmic censorship hypothesis is violated by nearly extremal Reissner-Nordström-de Sitter black holes. It was argued that perturbations of such a black hole decay sufficiently rapidly that the perturbed spacetime can be extended across the Cauchy horizon as a weak solution of the equations of motion. In this paper we consider the case of Kerr-de Sitter black holes. We find that, for any nonextremal value of the black hole parameters, there are quasinormal modes which decay sufficiently slowly to ensure that strong cosmic censorship is respected. Our analysis covers both scalar field and linearized gravitational perturbations.

  2. Future changes of the atmospheric composition and the impact of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Grewe, V.; Dameris, M.; Hein, R.; Sausen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Steil, B. [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany). Abt. Chemie der Atmosphaere

    1999-05-01

    The development of the future atmospheric chemical composition, with respect of NO{sub y} and O{sub 3} is investigated by means of the off-line coupled dynamic-chemical general circulation model ECHAM3/CHEM. Two time slice experiments have been performed for the years 1992 and 2015, which include changes in sea surface temperatures, greenhouse gas concentrations, emissions of CFCs, NO{sub x} and other species, i.e., the 2015 simulation accounts for changes in chemically relevant emissions and for a climate change and its impact on air chemistry. The 2015 simulation clearly shows a global increase in ozone except for large areas of the lower stratosphere, where no significant changes or even decreases in the ozone concentration are found. For a better understanding of the importance of (A) emissions like NO{sub x} and CFCs, (B) future changes of air temperature and water vapour concentration, and (C) other dynamic parameters, like precipitation and changes in the circulation, i.e. wind speed, diabatic circulation, stratosphere-troposphere-exchange, the simulation of the future atmosphere has been performed stepwise. This method requires a climate-chemistry model without interactive coupling of chemical species. Model results show that the direct effect of emissions (A) plays a major role for the composition of the future atmosphere, but they also clearly show that climate change has a significant impact and strongly reduces the NO{sub y} and ozone concentration in the lower stratosphere. (orig.)

  3. A Hot Downflowing Model Atmosphere for Umbral Flashes and the Physical Properties of Their Dark Fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, V. M. J.; Mathioudakis, M. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, BT7 1NN, Northern Ireland (United Kingdom); Socas-Navarro, H. [Instituto de Astrofísica de Canarias, Avda vía Láctea S/N, E-38205 La Laguna, Tenerife (Spain); Rodríguez, J. de la Cruz, E-mail: v.henriques@qub.ac.uk [Institute for Solar Physics, Department of Astronomy, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden)

    2017-08-20

    We perform non-LTE inversions in a large set of umbral flashes, including the dark fibrils visible within them, and in the quiescent umbra by using the inversion code NICOLE on a set of full Stokes high-resolution Ca ii λ 8542 observations of a sunspot at disk center. We find that the dark structures have Stokes profiles that are distinct from those of the quiescent and flashed regions. They are best reproduced by atmospheres that are more similar to the flashed atmosphere in terms of velocities, even if with reduced amplitudes. We also find two sets of solutions that finely fit the flashed profiles: a set that is upflowing, featuring a transition region that is deeper than in the quiescent case and preceded by a slight dip in temperature, and a second solution with a hotter atmosphere in the chromosphere but featuring downflows close to the speed of sound at such heights. Such downflows may be related, or even dependent, on the presence of coronal loops, rooted in the umbra of sunspots, as is the case in the region analyzed. Similar loops have been recently observed to have supersonic downflows in the transition region and are consistent with the earlier “sunspot plumes,” which were invariably found to display strong downflows in sunspots. Finally, we find, on average, a magnetic field reduction in the flashed areas, suggesting that the shock pressure is moving field lines in the upper layers.

  4. CHARACTERIZING THE ATMOSPHERES OF TRANSITING ROCKY PLANETS AROUND LATE-TYPE DWARFS

    International Nuclear Information System (INIS)

    Palle, E.; Garcia Munoz, A.; Zosorio, M. R. Zapatero

    2011-01-01

    Visible and near-infrared spectra of transiting hot Jupiter planets have recently been observed, revealing some of the atmospheric constituents of their atmospheres. In the near future, it is probable that primary and secondary eclipse observations of Earth-like rocky planets will also be achieved. The characterization of Earth's transmission spectrum has shown that both major and trace atmospheric constituents may present strong absorption features, including important bio-markers such as water, oxygen, and methane. Our simulations using a recently published empirical Earth's transmission spectrum, and the stellar spectra for a variety of stellar types, indicate that the new generation of extremely large telescopes, such as the proposed 42 m European Extremely Large Telescope, could be capable of retrieving the transmission spectrum of an Earth-like planet around very cool stars and brown dwarfs (T eff ≤ ∼3100 K). For a twin of Earth around a star with T eff ∼ 3100 K (M4), for example, the spectral features of H 2 O, CH 4 , CO 2 , and O 2 in the wavelength range between 0.9 and 2.4 μm can simultaneously be detected within 100 hr of observing time, or even less for a late-M star. Such detection would constitute proof for the existence of life in that planet. The detection time can be reduced to a few hours for a super-Earth type of planet with twice Earth's radius.

  5. Noise Radiation Of A Strongly Pulsating Tailpipe Exhaust

    Science.gov (United States)

    Peizi, Li; Genhua, Dai; Zhichi, Zhu

    1993-11-01

    The method of characteristics is used to solve the problem of the propagation of a strongly pulsating flow in an exhaust system tailpipe. For a strongly pulsating exhaust, the flow may shock at the pipe's open end at some point in a pulsating where the flow pressure exceeds its critical value. The method fails if one insists on setting the flow pressure equal to the atmospheric pressure as the pipe end boundary condition. To solve the problem, we set the Mach number equal to 1 as the boundary condition when the flow pressure exceeds its critical value. For a strongly pulsating flow, the fluctuations of flow variables may be much higher than their respective time averages. Therefore, the acoustic radiation method would fail in the computation of the noise radiation from the pipe's open end. We simulate the exhaust flow out of the open end as a simple sound source to compute the noise radiation, which has been successfully applied in reference [1]. The simple sound source strength is proportional to the volume acceleration of exhaust gas. Also computed is the noise radiation from the turbulence of the exhaust flow, as was done in reference [1]. Noise from a reciprocating valve simulator has been treated in detail. The radiation efficiency is very low for the pressure range considered and is about 10 -5. The radiation efficiency coefficient increases with the square of the frequency. Computation of the pipe length dependence of the noise radiation and mass flux allows us to design a suitable length for an aerodynamic noise generator or a reciprocating internal combustion engine. For the former, powerful noise radiation is preferable. For the latter, maximum mass flux is desired because a freer exhaust is preferable.

  6. Geoethical suggestions for reducing risk of next (not only strong) earthquakes

    Science.gov (United States)

    Nemec, Vaclav

    2013-04-01

    Three relatively recent examples of earthquakes can be used as a background for suggesting geoethical views into any prediction accompanied by a risk analysis. ĹAquila earthquake (Italy - 2009): ĹAquila was largely destroyed by earthquakes in 1315, 1319, 1452, 1461, 1501, 1646, 1703 (until that time altogether about 3000 victims) and 1786 (about 6000 victims of this event only). The city was rebuilt and remained stable until October 2008, when tremors began again. From January 1 through April 5, 2009, additional 304 tremors were reported. When after measuring increased levels of radon emitted from the ground a local citizen (for many years working for the Italian National Institute of Astrophysics) predicted a major earthquake on Italian television, he was accused of being alarmist. Italy's National Commission for Prediction and Prevention of Major Risks met in L'Aquila for one hour on March 31, 2009, without really evaluating and characterising the risks that were present. On April 6 a 6.3 magnitude earthquake struck Aquila and nearby towns, killing 309 people and injuring more than 1,500. The quake also destroyed roughly 20,000 buildings, temporarily displacing another 65,000 people. In July 2010, prosecutor Fabio Picuti charged the Commission members with manslaughter and negligence for failing to warn the public of the impending risk. Many international organizations joined the chorus of criticism wrongly interpreting the accusation and sentence at the first stage as a problem of impossibility to predict earthquakes. - The Eyjafjallajokull volcano eruption (Iceland - 2010) is a reminder that in our globalized, interconnected world because of the increased sensibility of the new technology even a relatively small natural disaster may cause unexpected range of problems. - Earthquake and tsunami (Japan - 2011) - the most powerful known earthquake ever to have hit Japan on March 11. Whereas the proper earthquake with the magnitude of 9.0 has caused minimum of deaths (incomparably lower than tragic events from 1923) the tsunami has broken any known record. The existing anti-tsunami measures have appeared to be appropriate to expectations given by unsatisfactory safety limits extended to the human memory experience. Conclusions of geoethics: a) a new legal interpretation of "false alarms" and reasonable risk and danger levels is to be established (up-dating internationally acceptable definitions and protection measures); b) any positive prediction for any known real natural disaster (whoever made it) is to be precisely analysed by competent institutes avoiding any underestimation of "incompetent" researchers and amateurs and respecting diversity of scientific research "schools"; c) a reciprocal respect between scientists and the population is to be based on the use of a reciprocally understandable language; d) scientists as well as media are obliged to respect and publish the complete truth about facts with clearly defined words to avoid any misinterpretation of results; e) consequences of relatively "minor" earthquakes are no more limited only to an adjacent local area; f) the appropriate programs for computerized predictions are to be under a permanent control of validity (using alternative parameters and incorporating verified or supposed time-tables of events from the past); g) any scientist when accepting a function in a State organ has to accept his role with high personal responsibility for and respect to the goals, work and results of such a commission; h) any effective prevention of the population is to be based on a mutual consensus preferring in any stage the common good instead of particular or personal interests and respecting human lives as the top value priority.

  7. Natural strong CP conservation in flipped physics

    Energy Technology Data Exchange (ETDEWEB)

    Frampton, P.H. (Institute of Field Physics, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC (USA)); Kephart, T.W. (Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (USA))

    1990-08-13

    A natural axion-free solution of the strong {ital CP} problem {ital at} {ital tree} {ital level} is noted within an E(6) grand unified theory. Using this as a springboard, it is shown that several flipped SU(5) theories which occur in superstring phenomenology contain within them a mechanism which enforces {bar {theta}}=0 at high accuracy.

  8. Riesz basis for strongly continuous groups.

    NARCIS (Netherlands)

    Zwart, Heiko J.

    Given a Hilbert space and the generator of a strongly continuous group on this Hilbert space. If the eigenvalues of the generator have a uniform gap, and if the span of the corresponding eigenvectors is dense, then these eigenvectors form a Riesz basis (or unconditional basis) of the Hilbert space.

  9. Earthquake source model using strong motion displacement

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  10. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...

  11. Discrete symmetries, strong CP problem and gravity

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1993-05-01

    Spontaneous breaking of parity or time reversal invariance offers a solution to the strong CP problem, the stability of which under quantum gravitational effects provides an upper limit on the scale of symmetry breaking. Even more important, these Planck scale effects may provide a simple and natural way out of the resulting domain wall problem. (author). 22 refs

  12. Phase transition from strong-coupling expansion

    International Nuclear Information System (INIS)

    Polonyi, J.; Szlachanyi, K.

    1982-01-01

    Starting with quarkless SU(2) lattice gauge theory and using the strong-coupling expansion we calculate the action of the effective field theory which corresponds to the thermal Wilson loop. This effective action makes evident that the quark liberating phase transition traces back to the spontaneous breaking of a global Z(2) symmetry group. It furthermore describes both phases qualitatively. (orig.)

  13. The stability of the strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1978-01-01

    The perturbation of the classical solution to a strong gravity model given by Salam and Strathdee is investigated. Using the Hamiltonian formalism it is shown that this static and spherically symmetric solution is stable under the odd parity perturbations provided some parameters in the solution are suitably restricted

  14. Chaos desynchronization in strongly coupled systems

    International Nuclear Information System (INIS)

    Wu Ye; Liu Weiqing; Xiao, Jinghua; Zhan Meng

    2007-01-01

    The dynamics of chaos desynchronization in strongly coupled oscillator systems is studied. We find a new bifurcation from synchronous chaotic state, chaotic short wave bifurcation, i.e. a chaotic desynchronization attractor is new born in the systems due to chaos desynchronization. In comparison with the usual periodic short wave bifurcation, very rich but distinct phenomena are observed

  15. Strong motion duration and earthquake magnitude relationships

    International Nuclear Information System (INIS)

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ''strong motion duration'' has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions

  16. Physics challenges in the strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, S.D.

    1991-01-01

    An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.

  17. Strongly \\'etale difference algebras and Babbitt's decomposition

    OpenAIRE

    Tomašić, Ivan; Wibmer, Michael

    2015-01-01

    We introduce a class of strongly \\'{e}tale difference algebras, whose role in the study of difference equations is analogous to the role of \\'{e}tale algebras in the study of algebraic equations. We deduce an improved version of Babbitt's decomposition theorem and we present applications to difference algebraic groups and the compatibility problem.

  18. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    hanced values needed to interpret the data at higher energies point towards the importance of strong-coupling effects. ... when all secondary particles have been created. For short times in the initial phase ... It is decisive for a proper representation of the available data for relativistic heavy-ion collisions at and beyond SPS.

  19. Strongly coupled semidirect mediation of supersymmetry breaking

    International Nuclear Information System (INIS)

    Ibe, M.; Izawa, K.-I.; Nakai, Y.

    2009-01-01

    Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard-model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard-model gaugino masses for a small mediator mass without breaking the standard-model symmetries.

  20. Strong Turbulence in Low-beta Plasmas

    DEFF Research Database (Denmark)

    Tchen, C. M.; Pécseli, Hans; Larsen, Søren Ejling

    1980-01-01

    An investigation of the spectral structure of turbulence in a plasma confined by a strong homogeneous magnetic field was made by means of a fluid description. The turbulent spectrum is divided into subranges. Mean gradients of velocity and density excite turbulent motions, and govern the production......-cathode reflex arc, Stellarator, Zeta discharge, ionospheric plasmas, and auroral plasma turbulence....