Science.gov

Sample records for air mass circulation

  1. Portable oven air circulator

    DOEpatents

    Jorgensen, Jorgen A.; Nygren, Donald W.

    1983-01-01

    A portable air circulating apparatus for use in cooking ovens which is used to create air currents in the oven which transfer heat to cooking foodstuffs to promote more rapid and more uniform cooking or baking, the apparatus including a motor, fan blade and housing of metallic materials selected from a class of heat resistant materials.

  2. Monitoring Air Circulation Under Reduced Pressures

    NASA Astrophysics Data System (ADS)

    Rygalov, Vadim

    Adequate air circulation is required for controlled environments to maintain uniform temperature and humidity control, and hence the ability to measure air flow accurately is important. Human and associated life support habitats (e.g.,. plant production systems) for future space missions will likely be operated at pressures less than 100 kPa to minimize gas leakage and structural mass. Under such reduced pressures, the outputs from conventional anemometers for monitoring air flow can change and require re-calibration. These effects of atmospheric pressure on different types of air flow measurements are not completely understood; hence we compared the performance of several air flow sensors across a range of hypobaric pressures. Sensors included a propeller type anemometer, a hot-wire anemometer, and a Pitot-tube based device. Theoretical schematics (including mathematical models) underlying these measurements were developed. Results demonstrated that changes in sensor outputs were predictable based on their operating principles, and that corrections could be developed for sensors calibrated under normal Earth atmosphere pressure ( 100 kPa) and then used at different pressures. The potential effects of hypobaric atmospheres and their altered air flows on plant physiology are also discussed.

  3. SpaceX Dragon Air Circulation System

    NASA Technical Reports Server (NTRS)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  4. Changes in large-scale air circulation and connection with climate variables in Romania

    NASA Astrophysics Data System (ADS)

    Stefan, Sabina; Barbu, Nicu

    2016-04-01

    The aim of this paper is the analysis of the relationship between climate variables (seasonal mean air temperature - T2m, and seasonal amount of precipitation - PP) and large-scale air circulation. In order to achieve this, the air circulation types were derived from GrossWetterTypen (GWT) and WetterLagenKlassifikation (WLK) Catalogues developed within COST733 framework. Daily air circulation types are divided into 18 groups according to the GWT Catalogue and in 40 groups according to the WLK Catalogue and for each type winter (DJF) and summer (JJA) occurrence frequency were calculated. To this end the Pearson correlation coefficient between climate variables and circulation type's frequency were computed. The results reveals that in wintertime the GWT circulation types captures better than WLK circulation types the T2m variability in time that for summer the WLK circulation types captures better than GWT circulation types. This is due to the seasonal variability of the horizontal extension of air masses. We found that the T2m is positive correlated to anticyclonic circulation types and negative correlated with cyclonic types and the PP is correlated to the cyclonic circulation and negative correlated to anticyclonic ones. Additionally, the trend significance of the climate variables as well as air circulation types have been analysed with the non-parametric Mann-Kendall test. The changes of the trends were detected by employing the non-parametric Pettit test. From the trend analysis we can state that some of the anticyclonic circulation types presents upward tendency and some of the cyclonic circulation presents downward tendency. This is an important results because explain the upward trend of the T2m and the downward trend of the PP.

  5. Pellet stove with enhanced air circulation efficiency

    SciTech Connect

    Burke, T.M.; Burke, W.L.

    1992-06-23

    This patent describes a stove for converting fuel to heat. It comprises means defining a fuel storage area; means for pressurizing the fuel storage area, the means comprising a single air blowing means; means defining a combustion area for allowing combustion to take place; vent means for venting air from the combustion area; means defining a heat exchange area adjacent to and in contact with the combustion area for removing heat from the combustion area; and means for conducting pressurized air from the fuel storage area directly to the combustion area and directly to the heat exchange area.

  6. Numerical simulation of temperature-driven air circulation and oxygen transport in unsaturated porous media

    SciTech Connect

    Guo, Weixing; Parizek, R.R. . Dept. of Geosciences)

    1992-01-01

    Temperature-driven air circulation within unsaturated porous media is receiving increasing attention in the studies of volatile organic component transport and remediation, safety assessment of radioactive waste repositories, soil moisture redistribution, etc. This coupled physical process also plays an important role in supplying oxygen to coal mine spoil where acid mine drainage is generated. To investigate the availability of oxygen within mine spoil, as the primary oxidant in acid reactions, a transient two-dimensional numerical model (HOT) which incorporates temperature-driven air circulation, dispersion-advection oxygen transport in gas phase, steady-state groundwater flow and chemical reactions, has been created. Energy and mass transfer across liquid and gas phases are included. Shrinking core models are used to simulate the kinetics of acid reactions. The rates of heat generation and oxygen consumption are determined stoichiometrically. The generalized Newton-Raphson method is used to linearize the partial differential equations describing heat and mass transfer in porous media. HOT has been used in studies of acid mine drainage generation within coal mine spoil and successfully compared with in-situ temperature measurements. This model may also be applied for some other research including soil vapor extraction, radon migration in soils and temperature prediction of nuclear waste repositories within unsaturated rocks.

  7. Quantifying the effects of mixing and residual circulation on trends of stratospheric mean age of air

    NASA Astrophysics Data System (ADS)

    Ploeger, Felix; Abalos, Marta; Birner, Thomas; Konopka, Paul; Legras, Bernard; Müller, Rolf; Riese, Martin

    2015-04-01

    Trends in stratospheric mean age of air are driven both by changes in the (slow, large scale) residual mean mass circulation and by changes in (fast, locally acting) eddy mixing. However, to what degree both effects affect mean age trends is an open question. Here, we present a method that allows the effects of mixing and residual circulation on trends of mean age of air to be quantified. This method is based on mean age simulations with the Lagrangian chemistry transport model CLaMS driven by ERA-Interim reanalysis, and on the mean age tracer continuity equation integrated along the residual circulation. CLaMS simulated climatological mean age in the lower stratosphere shows reliable agreement with balloon borne in-situ obsevations and with satellite observations by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding). During 1990--2013, CLaMS simulated mean age decreases throughout most of the stratosphere, qualitatively consistent with results based on climate model simulations (e.g., Butchart et al., 2010). Remarkably, in the Northern hemisphere subtropics and mid-latitudes above about 24km CLaMS mean age trends are insignificant, consistent with published mean age trends from in-situ observations (Engel et al., 2009). Furthermore, during 2002--2012 CLaMS mean age changes show a clear hemispheric asymmetry in agreement with MIPAS satellite observations (Stiller et al., 2012; Ploeger et al., 2014) and HCl decadal changes (Mahieu et al., 2014). We find that changes in the transit time along the residual circulation alone cannot explain the mean age trends, and including the effect of mixing integrated along the air parcel history is essential. Therefore, differences in mean age trends between models or between models and observations are likely related to differences in the integrated effect of mixing on mean age of air. Above about 550K, trends in the integrated mixing effect appear to be likely coupled to residual circulation changes. References

  8. Influence of large-scale atmospheric circulation on marine air intrusion toward the East Antarctic coast

    NASA Astrophysics Data System (ADS)

    Kurita, Naoyuki; Hirasawa, Naohiko; Koga, Seizi; Matsushita, Junji; Steen-Larsen, Hans Christian; Masson-Delmotte, Valérie; Fujiyoshi, Yasushi

    2016-09-01

    Marine air intrusions into Antarctica play a key role in high-precipitation events. Here we use shipboard observations of water vapor isotopologues between Australia and Syowa on the East Antarctic coast to elucidate the mechanism by which large-scale circulation influences marine air intrusions. The temporal isotopic variations at Syowa reflect the meridional movement of a marine air front. They are also associated with atmospheric circulation anomalies that enhance the southward movement of cyclones over the Southern Ocean. The relationship between large-scale circulation and the movement of the front is explained by northerly winds which, in association with cyclones, move toward the Antarctic coast and push marine air with isotopically enriched moisture into the inland covered by glacial air with depleted isotopic values. Future changes in large-scale circulation may have a significant impact on the frequency and intensity of marine air intrusion into Antarctica.

  9. Relations between atmospheric circulation and mass balance of South Cascade Glacier, Washington, U.S.A.

    SciTech Connect

    McCabe, G.J.; Fountain, A.G.

    1995-08-01

    The yearly net mass balance of South Cascade Glacier, Washington, has decreased since the mid-1970s. Results show that the decrease in winter mass balance is caused, in part, by changes in winter mean atmospheric circulation that began during the mid-1970s. Approximately 60% of the variability in winter mass balance can be explained by variations in winter mean 700-mb heights over western Canada. Since the mid-1970s, there has been an increase in winter mean 700-mb heights over western Canada and the northern western contiguous United States and a decrease in winter mean 700-mb heights in the eastern North Pacific Ocean centered near the Aleutian Islands. These changes in atmospheric circulation indicate a decrease in the movement of storms and moisture from the Pacific Ocean into the western contiguous United States. In addition, the increase in winter mean 700-mb heights over western Canada and the northern western contiguous United States indicates an increase in subsidence, which results in a warming and drying of the air that further reduces precipitation and also increases the ratio of rain to snow during the cold season. These factors contribute to below-average winter mass balances. 43 refs., 13 figs.

  10. Coastal recirculation potential affecting air pollutants in Portugal: The role of circulation weather types

    NASA Astrophysics Data System (ADS)

    Russo, Ana; Gouveia, Célia; Levy, Ilan; Dayan, Uri; Jerez, Sonia; Mendes, Manuel; Trigo, Ricardo

    2016-06-01

    Coastal zones are under increasing development and experience air pollution episodes regularly. These episodes are often related to peaks in local emissions from industry or transportation, but can also be associated with regional transport from neighbour urban areas influenced by land-sea breeze recirculation. This study intends to analyze the relation between circulation weather patterns, air mass recirculation and pollution levels in three coastal airsheds of Portugal (Lisbon, Porto and Sines) based on the application of an objective quantitative measure of potential recirculation. Although ventilation events have a dominant presence throughout the studied 9-yrs period on all the three airsheds, recirculation and stagnation conditions occur frequently. The association between NO2, SO2 and O3 levels and recirculation potential is evident during summer months. Under high average recirculation potential and high variability, NO2 and SO2 levels are higher for the three airsheds, whilst for O3 each airshed responds differently. This indicates a high heterogeneity among the three airsheds in (1) the type of emission - traffic or industry - prevailing for each contaminant, and (2) the response to the various circulation weather patterns and recirculation situations. Irrespectively of that, the proposed methodology, based on iterative K-means clustering, allows to identify which prevailing patterns are associated with high recirculation potential, having the advantage of being applicable to any geographical location.

  11. Gas circulation and mass exchange between animal and plant units

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Tong, Ling; Hu, Enzhu

    To investigate the gas circulation and mass exchange relations among animal, plant and other biological units in the bioregenarative life support system, a closed cultivating system consisting of animal breeding chamber and plant growing chamber was established. This facility is 1.4 m high with the bottom area measuring 1.4 m X 0.8 m. In the animal chamber, silkworms in the multistage instars from the first instar to the third day in the fifth instar were bred; in the plant chamber, lettuce with sharp leaves were grown in a staggered manner. After transferring the silkworms in different instars hatched in the artificial climate box proportionally, utilizing mulberry leaves supplied from the outside of the closed cultivating system to feed the silkworms from the first instar to the third instar; fed the silkworms after the third instar to the third day in the fifth instar with the lettuce leaves grown in the closed facility, meanwhile, took out silkworms' excretion whose amount was in proportion to that of the mulberry leaves input into the facility. Furthermore, the silkworms on the third day in the fifth instar were took out to provide animal protein with high quality for astronauts at certain intervals and the next batch of the silkworms in the first instar were put into the animal chamber. In this cultivating process, the O2 cycle period and CO2 concentration change were investigated, moreover, the transfer and transforming ways of carbon and other elements were determined.

  12. The Thermal Circulation on Kilimanjaro, Tanzania and its Relevance to Summit Ice-Field Mass Balance.

    NASA Astrophysics Data System (ADS)

    Pepin, N. C.; Duane, W. J.

    2008-12-01

    It is well known that mountains create their own climates. On Kilimanjaro, which is the tallest free standing mountain in Africa, the intense tropical sunlight generates a strong diurnal mountain circulation which transports moisture up the mountain during the day and back downslope at night. This process has strong consequences for development of cloud cover, precipitation, and hence ice-field mass balance on the summit crater. We compare surface climate (temperature, moisture and wind) measured at ten elevations on Kilimanjaro, with equivalent observations in the free atmosphere from NCEP/NCAR reanalysis data for September 2004 to July 2008. There are no simple temporal trends over this period in either surface of free- air data. Correlations between daily surface and free air temperatures are greatest below 2500 metres, meaning that synoptic (inter-diurnal) variability is the major control here. In contrast, temperatures and moisture on the higher slopes above treeline (about 3000 m) are strongly decoupled from the free atmosphere, showing intense heating/cooling by day/night (more than 5°C). The sparsely vegetated upper slopes are the focus for the most intense heating and upslope winds develop by mid-morning. The forest on the lower slopes acts as a moisture source, with large vapour pressure excesses reported (5 mb) which move upslope reaching the crater in the afternoon before subsiding downslope at night. The montane thermal circulation is more effective at upslope moisture transport during January as compared with July. Fluctuations in upper air flow strength and direction (at 500 mb) surprisingly have limited influence on the strength of surface heating and upslope moisture advection. This finding suggests that local changes in surface characteristics such as deforestation could have a strong influence on the mountain climate and the summit ice fields on Kilimanjaro, and make mass-balance somewhat divorced from larger-scale advective changes associated

  13. Recent accelerating mass loss of southeast Tibetan glaciers and the relationship with changes in macroscale atmospheric circulations

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Guo, Xiaofeng; Yao, Tandong; Zhu, Meilin; Wang, Yongjie

    2016-08-01

    The mass balance history (1980-2010) of a monsoon-dominated glacier in the southeast Tibetan Plateau is reconstructed using an energy balance model and later interpreted with regard to macroscale atmospheric variables. The results show that this glacier is characterized by significant interannual mass fluctuations over the past three decades, with a remarkably high mass loss during the recent period of 2003-2010. Analysis of the relationships between glacier mass balance and climatic variables shows that interannual temperature variability in the monsoonal season (June-September) is a primary driver of its mass balance fluctuations, but monsoonal precipitation tends to play an accentuated role for driving the observed glacier mass changes due to their covariation (concurrence of warm/dry and cold/wet climates) in the monsoon-influenced southeast Tibetan Plateau. Analysis of the atmospheric circulation pattern reveals that the predominance of anticyclonic/cyclonic circulations prevailing in the southeastern/northern Tibetan Plateau during 2003-2010 contributes to increased air temperature and decreased precipitation in the southeast Tibetan Plateau. Regionally contrasting atmospheric circulations explain the distinct mass changes between in the monsoon-influenced southeast Tibetan Plateau and in the north Tibetan Plateau/Tien Shan Mountains during 2003-2010. The macroscale climate change seems to be linked with the Europe-Asia teleconnection.

  14. The impact of circulation patterns on regional transport pathways and air quality over Beijing and its surroundings

    NASA Astrophysics Data System (ADS)

    Zhang, J. P.; Zhu, T.; Zhang, Q. H.; Li, C. C.; Shu, H. L.; Ying, Y.; Dai, Z. P.; Wang, X.; Liu, X. Y.; Liang, A. M.; Shen, H. X.; Yi, B. Q.

    2012-06-01

    This study investigated the air pollution characteristics of synoptic-scale circulation in the Beijing megacity, and provided quantitative evaluation of the impacts of circulation patterns on air quality during the 2008 Beijing Summer Olympics. Nine weather circulation types (CTs) were objectively identified over the North China region during 2000-2009, using obliquely rotated T-mode principal component analysis (PCA). The resulting CTs were examined in relation to the local meteorology, regional transport pathways, and air quality parameters, respectively. The FLEXPART-WRF model was used to calculate 48-h backward plume trajectories for each CT. Each CT was characterized with distinct local meteorology and air mass origin. CT 1 (high pressure to the west with a strong pressure gradient) was characterized by a northwestern air mass origin, with the smallest local and southeasterly air mass sources, and CT 6 (high pressure to the northwest) had air mass sources mostly from the north and east. On the contrary, CTs 5, 8, and 9 (weak pressure field, high pressure to the east, and low pressure to the northwest, respectively) were characterized by southern and southeastern trajectories, which indicated a greater influence of high pollutant emission sources. In turn, poor air quality in Beijing (high loadings of PM10, BC, SO2, NO2, NOx, O3, AOD, and low visibility) was associated with these CTs. Good air quality in Beijing was associated with CTs 1 and 6. The average visibilities (with ±1σ) in Beijing for CTs 1 and 6 during 2000-2009 were 18.5 ± 8.3 km and 14.3 ± 8.5 km, respectively. In contrast, low visibility values of 6.0 ± 3.5 km, 6.6 ± 3.7 km, and 6.7 ± 3.6 km were found in CTs 5, 8, and 9, respectively. The mean concentrations of PM10 for CTs 1, 6, 5, 8, and 9 during 2005-2009 were 90.3 ± 76.3 μg m-3, 111.7 ± 89.6 μg m-3, 173.4 ± 105.8 μg m-3, 158.4 ± 90.0 μg m-3, and 151.2 ± 93.1 μg m-3, respectively. Analysis of the relationship between

  15. The Effective Mass of a Ball in the Air

    ERIC Educational Resources Information Center

    Messer, J.; Pantaleone, J.

    2010-01-01

    The air surrounding a projectile affects the projectile's motion in three very different ways: the drag force, the buoyant force, and the added mass. The added mass is an increase in the projectile's inertia from the motion of the air around it. Here we experimentally measure the added mass of a spherical projectile in air. The results agree well…

  16. 24 CFR 3280.715 - Circulating air systems.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... incandescent particles dropped through the register or furnace such as directly under floor registers and the... provided shall be counted as return air area. (c) Joints and seams. Joints and seams of sheet metal...

  17. 24 CFR 3280.715 - Circulating air systems.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... incandescent particles dropped through the register or furnace such as directly under floor registers and the... provided shall be counted as return air area. (c) Joints and seams. Joints and seams of sheet metal...

  18. 24 CFR 3280.715 - Circulating air systems.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... incandescent particles dropped through the register or furnace such as directly under floor registers and the... provided shall be counted as return air area. (c) Joints and seams. Joints and seams of sheet metal...

  19. 24 CFR 3280.715 - Circulating air systems.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... incandescent particles dropped through the register or furnace such as directly under floor registers and the... provided shall be counted as return air area. (c) Joints and seams. Joints and seams of sheet metal...

  20. 24 CFR 3280.715 - Circulating air systems.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... incandescent particles dropped through the register or furnace such as directly under floor registers and the... provided shall be counted as return air area. (c) Joints and seams. Joints and seams of sheet metal...

  1. Natural Circulation Patterns in the VHTR Air-Ingress Accident and Related Issues

    SciTech Connect

    Chang H. Oh; Eung S. Kim

    2012-08-01

    Natural circulation patterns in the VHTR during a hypothetical air-ingress accident have been investigated using computational fluid dynamic (CFD) methods in order to compare results from the previous 1-D model which was developed using GAMMA code for the air-ingress analyses. The GT-MHR 600 MWt reactor was selected to be the reference design and modeled by a half symmetric 3-D geometry using FLUENT 6.3, a commercial CFD code. CFD simulations were carried out as the steady-state calculation, and the boundary conditions were either assumed or provided from the 1-D GAMMA code results. Totally, 12 different cases have been reviewed, and many notable results have been obtained through in this work. According to the simulations, natural circulation patterns in the reactor were quite different from the previous 1-D assumptions. A large re-circulation flow with thermal stratification phenomena was clearly observed in the hot-leg and the lower plenum in the 3-D model. This re-circulation flow provided about an order faster air-ingress speed (0.46 m/s in superficial velocity) than previously predicted by 1-D modeling (0.02~0.03 m/s). It indicates that the 1-D air-ingress modeling may significantly distort the air-ingress scenario and consequences. In addition, complicated natural circulation patterns are eventually expected to result in very complex graphite oxidations and corrosion behaviors.

  2. Air Mass Origin in the Arctic and its Response to Future Warming

    NASA Technical Reports Server (NTRS)

    Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

    2014-01-01

    We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

  3. The impact of circulation patterns on regional transport pathways and air quality over Beijing and its surroundings

    NASA Astrophysics Data System (ADS)

    Zhang, J. P.; Zhu, T.; Zhang, Q. H.; Li, C. C.; Shu, H. L.; Ying, Y.; Dai, Z. P.; Liu, X. Y.; Liang, A. M.; Shen, H. X.

    2011-12-01

    This study investigated the air pollution characteristics of synoptic-scale circulation in the Beijing megacity, and provided holistic evaluation of the impacts of circulation patterns on air quality during the 2008 Beijing Summer Olympics. Nine weather circulation types (CTs) were objectively identified over the North China region during 2000-2009, using obliquely rotated T-mode principal component analysis (PCA). The resulting CTs were examined in relation to the local meteorology, regional transport pathways, and air quality parameters, respectively. The FLEXPART-WRF model was used to calculate 48-h backward plume trajectories for each CT. Nine CTs were characterized, with distinct local meteorology and air mass origins. CT 1 (high to the west with a strong pressure gradient) was characterized by a northwestern origin, with the smallest local and southeasterly air mass sources, and CT 6 (high to the northwest) had air mass sources mostly from the north and east. In contrast, CTs 5, 8, and 9 (unique, high to the east, and low to the northwest, respectively) were characterized by southern and southeastern trajectories, which indicated a greater influence of high pollutant emission sources. In turn, poor air quality in Beijing (high loadings of PM10, BC, SO2, NO2, O3, AOD, and low visibility) was associated with these CTs. Good air quality in Beijing was associated with CTs 1 and 6. The average visibilities (with ±1 σ) in Beijing for CTs 1 and 6 during 2000-2009 were 18.5 ± 8.3 km and 14.3 ± 8.5 km, respectively. In contrast, poor visibility values of 6.0 ± 3.5 km, 6.6 ± 3.7 km, and 6.7 ± 3.6 km were found in CTs 5, 8, and 9, respectively. The mean concentrations of PM10 for CTs 1, 6, 5, 8, and 9 during 2005-2009 were 90.3 ± 76.3 μg m-3, 111.7 ± 89.6 μg m-3, 173.4 ± 105.8 μg m-3, 158.4 ± 90.0 μg m-3, and 151.2 ± 93.1 μg m-3, respectively. Analysis of the relationship between circulation pattern and air quality during the emission control period

  4. An objective definition of air mass types affecting Athens, Greece; the corresponding atmospheric pressure patterns and air pollution levels.

    PubMed

    Sindosi, O A; Katsoulis, B D; Bartzokas, A

    2003-08-01

    This work aims at defining characteristic air mass types that dominate in the region of Athens, Greece during the cold (November-March) and the warm (May-September) period of the year and also at evaluating the corresponding concentration levels of the main air pollutants. For each air mass type, the mean atmospheric pressure distribution (composite maps) over Europe and the Mediterranean is estimated in order to reveal the association of atmospheric circulation with air pollution levels in Athens. The data basis for this work consists of daily values of thirteen meteorological and six pollutant parameters covering the period 1993-97. The definition of the characteristic air mass types is attempted objectively by using the methods of Factor Analysis and Cluster Analysis. The results show that during the cold period of the year there are six prevailing air mass types (at least 3% of the total number of days) and six infrequent ones. The examination of the corresponding air pollution concentration levels shows that the primary air pollutants appear with increased concentrations when light or southerly winds prevail. This is usually the case when a high pressure system is located over the central Mediterranean or a low pressure system lays over south Italy, respectively. Low levels of the primary pollutants are recorded under northeasterly winds, mainly caused by a high pressure system over Ukraine. During the warm period of the year, the southwestern Asia thermal low and the subtropical anticyclone of the Atlantic Ocean affect Greece. Though these synoptic systems cause almost stagnant conditions, four main air mass types are dominant and ten others, associated with extreme weather, are infrequent. Despite the large amounts of total solar radiation characterizing this period, ozone concentrations remain at low levels in central Athens because of its destruction by nitric oxide.

  5. Drought Variability in Eastern Part of Romania and its Connection with Large-Scale Air Circulation

    NASA Astrophysics Data System (ADS)

    Barbu, Nicu; Stefan, Sabina; Georgescu, Florinela

    2014-05-01

    Drought is a phenomenon that appears due to precipitation deficit and it is intensified by strong winds, high temperatures, low relative humidity and high insolation; in fact, all these factors lead to increasing of evapotranspiration processes that contribute to soil water deficit. The Standardized Precipitation Evapotranspiration Index (SPEI) take into account all this factors listed above. The temporal variability of the drought in Eastern part of Romania for 50 years, during the period 1961-2010, is investigated. This study is focused on the drought variability related to large scale air circulation. The gridded dataset with spatial resolution of 0.5º lat/lon of SPEI, (https://digital.csic.es/handle/10261/72264) were used to analyze drought periods in connection with large scale air circulation determinate from the two catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) defined in COST733Action. The GWT catalogue uses at input dataset the sea level pressure and the WLK catalogue uses as input dataset the geopotential field at 925 hPa and 500 hPa, wind at 700 hPa and total water content for entire atmospheric column. In this study we use the GWT catalogue with 18 circulation types and the WLK catalogue with 40 circulation types. The analysis for Barlad Hydrological Basin indicated that the negative values (that means water deficit - drought period) of SPEI are associated with prevailing anticyclonic regime and positive values (that means water excess - rainy period) of SPEI are associated with prevailing cyclonic regime as was expected. In last decade was observed an increase of dry period associated with an increase of anticyclonic activity over Romania. Using GWT18 catalogue the drought are associated with the north-eastern anticyclonic circulation type (NE-A). According to the WLK40 catalogue, the dominant circulation type associated with the drought is north-west-anticyclonic-dry anticyclonic (NW-AAD) type. keywords: drought, SPEI

  6. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  7. Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

    PubMed

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

  8. Regional climates in the GISS general circulation model: Surface air temperature

    NASA Technical Reports Server (NTRS)

    Hewitson, Bruce

    1994-01-01

    One of the more viable research techniques into global climate change for the purpose of understanding the consequent environmental impacts is based on the use of general circulation models (GCMs). However, GCMs are currently unable to reliably predict the regional climate change resulting from global warming, and it is at the regional scale that predictions are required for understanding human and environmental responses. Regional climates in the extratropics are in large part governed by the synoptic-scale circulation and the feasibility of using this interscale relationship is explored to provide a way of moving to grid cell and sub-grid cell scales in the model. The relationships between the daily circulation systems and surface air temperature for points across the continental United States are first developed in a quantitative form using a multivariate index based on principal components analysis (PCA) of the surface circulation. These relationships are then validated by predicting daily temperature using observed circulation and comparing the predicted values with the observed temperatures. The relationships predict surface temperature accurately over the major portion of the country in winter, and for half the country in summer. These relationships are then applied to the surface synoptic circulation of the Goddard Institute for Space Studies (GISS) GCM control run, and a set of surface grid cell temperatures are generated. These temperatures, based on the larger-scale validated circulation, may now be used with greater confidence at the regional scale. The generated temperatures are compared to those of the model and show that the model has regional errors of up to 10 C in individual grid cells.

  9. Relationship between climate extremes in Romania and their connection to large-scale air circulation

    NASA Astrophysics Data System (ADS)

    Barbu, Nicu; Ştefan, Sabina

    2015-04-01

    The aim of this paper is to investigate the connection between climate extremes (temperature and precipitation) in Romania and large-scale air circulation. Daily observational data of maximum air temperature and amount of precipitation for the period 1961-2010 were used to compute two seasonal indices associated with temperature and precipitation, quantifying their frequency, as follows: frequency of very warm days (FTmax90 ≥ 90th percentile), frequency of very wet days (FPp90; daily precipitation amount ≥ 90th percentile). Seasonally frequency of circulation types were calculated from daily circulation types determined by using two objective catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) from the COST733Action. Daily reanalysis data sets (sea level pressure, geopotential height at 925 and 500 hPa, u and v components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column) build up by NCEP/NCAR, with 2.5°/2.5° lat/lon spatial resolution, were used to determine the circulation types. In order to select the optimal domain size related to the FTmax90 and the FPp90, the explained variance (EV) has been used. The EV determines the relation between the variance among circulation types and the total variance of the variable under consideration. This method quantifies the discriminatory power of a classification. The relationships between climate extremes in Romania and large-scale air circulation were investigated by using multiple linear regression model (MLRM), the predictands are FTmax90 and FPp90 and the circulation types were used as predictors. In order to select the independent predictors to build the MLRM the collinearity and multicollinearity analysis were performed. The study period is dividend in two periods: the period 1961-2000 is used to train the MLRM and the period 2001-2010 is used to validate the MLRM. The analytical relationship obtained by using MLRM can be used for future projection

  10. Estimation and Validation of Oceanic Mass Circulation from the GRACE Mission

    NASA Technical Reports Server (NTRS)

    Boy, J.-P.; Rowlands, D. D.; Sabaka, T. J.; Luthcke, S. B.; Lemoine, F. G.

    2011-01-01

    Since the launch of the Gravity Recovery And Climate Experiment (GRACE) in March 2002, the Earth's surface mass variations have been monitored with unprecedented accuracy and resolution. Compared to the classical spherical harmonic solutions, global high-resolution mascon solutions allows the retrieval of mass variations with higher spatial and temporal sampling (2 degrees and 10 days). We present here the validation of the GRACE global mascon solutions by comparing mass estimates to a set of about 100 ocean bottom pressure (OSP) records, and show that the forward modelling of continental hydrology prior to the inversion of the K-band range rate data allows better estimates of ocean mass variations. We also validate our GRACE results to OSP variations modelled by different state-of-the-art ocean general circulation models, including ECCO (Estimating the Circulation and Climate of the Ocean) and operational and reanalysis from the MERCATOR project.

  11. Diabetes Coverage in Mass-Circulating Women's Magazines, 1995-2001

    ERIC Educational Resources Information Center

    Wallace, Lorraine Silver

    2003-01-01

    This review evaluates the accuracy of diabetes mellitus coverage in selected mass-circulating women's magazines from 1995 through 2001. The ProQuest database was searched to obtain all citations from five women's magazines ("Better Homes and Gardens," "Good Housekeeping," "Ladies' Home Journal," "Family Circle," and "Woman's Day") and three…

  12. Air sparging effectiveness: laboratory characterization of air-channel mass transfer zone for VOC volatilization.

    PubMed

    Braida, W J; Ong, S K

    2001-10-12

    Air sparging in conjunction with soil vapor extraction is one of many technologies currently being applied for the remediation of groundwater contaminated with volatile organic compounds (VOCs). Mass transfer at the air-water interface during air sparging is affected by various soil and VOC properties. In this study with a single air-channel apparatus, mass transfer of VOCs was shown to occur within a thin layer of saturated porous media next to the air channel. In this zone, the VOCs were found to rapidly deplete during air sparging resulting in a steep concentration gradient while the VOC concentration outside the zone remained fairly constant. The sizes of the mass transfer zone were found to range from 17 to 41 mm or 70d(50) and 215d(50) (d(50)=mean particle size) for low organic carbon content media (<0.01% OC). The size of the mass transfer zone was found to be proportional to the square root of the aqueous diffusivity of the VOC, and was affected by the mean particle size, and the uniformity coefficient. Effects of the volatility of the VOCs as represented by the Henry's law constants and the airflow rates on the mass transfer zone were found to be negligible but VOC mass transfer from air-water interface to bulk air phase seems to play a role. A general correlation for predicting the size of the mass transfer zone was developed. The model was developed using data from nine different VOCs and verified by two other VOCs. The existence of the mass transfer zone provides an explanation for the tailing effect of the air phase concentration under prolonged air sparging and the rebound in the VOC air phase concentration after the sparging system is turned off.

  13. The role of aerosol in altering North Atlantic atmospheric circulation in winter and air-quality feedbacks

    NASA Astrophysics Data System (ADS)

    Pausata, F. S. R.; Gaetani, M.; Messori, G.; Kloster, S.; Dentener, F. J.

    2014-09-01

    Numerical model scenarios of future climate depict a global increase in temperatures and changing precipitation patterns, driven by increasing greenhouse gas (GHG) concentrations. Aerosol concentrations also play an important role in altering Earth's radiation budget and consequently surface temperature. Here, we use the general circulation aerosol model ECHAM5-HAM, coupled to a mixed layer ocean model, to investigate the impacts of future air pollution mitigation strategies in Europe on winter atmospheric circulation over the North Atlantic. We analyze the extreme case of a maximum feasible end-of-pipe reduction of aerosols in the near future (2030), in combination with increasing GHG concentrations. Our results show a more positive North Atlantic Oscillation (NAO) mean state in the near future, together with a significant eastward shift of the southern centre of action of the sea level pressure (SLP). Moreover, we show a significantly increased blocking frequency over the western Mediterranean. By separating the aerosol and GHG impacts, our study suggests that the aerosol abatement in the near future may be the primary driver of such circulation changes. All these concomitant modifications of the atmospheric circulation over the Euro-Atlantic sector lead to more stagnant weather conditions that favor air pollutant accumulation in the Mediterranean, especially in the western sector. These changes in atmospheric circulation should be included in future air pollution mitigation assessments. Our results suggest that an evaluation of NAO changes in individual climate model simulations will allow an objective assessment of the role of changes in wintertime circulation on future air quality.

  14. Measurements of CO in an aircraft experiment and their correlation with biomass burning and air mass origin in South America

    NASA Astrophysics Data System (ADS)

    Boian, C.; Kirchhoff, V. W. J. H.

    Carbon monoxide (CO) measurements are obtained in an aircraft experiment during 1-7 September 2000, conducted over Central Brazil in a special region of anticyclonic circulation. This is a typical transport regime during the dry season (July-September), when intense biomass burning occurs, and which gives origin to the transport of burning poluents from the source to distant regions. This aircraft experiment included in situ measurements of CO concentrations in three different scenarios: (1) areas of fresh biomass burning air masses, or source areas; (2) areas of aged biomass burning air masses; and (3) areas of clean air or pristine air masses. The largest CO concentrations were of the order of 450 ppbv in the source region near Conceicao do Araguaia (PA), and the smallest value near 100 ppbv, was found in pristine air masses, for example, near the northeast coastline (clean air, or background region). The observed concentrations were compared to the number of fire pixels seen by the AVHRR satellite instrument. Backward isentropic trajectories were used to determine the origin of the air masses at each sampling point. From the association of the observed CO mixing ratios, fire pixels and air mass trajectories, the previous scenarios may be subdivided as follows: (1a) source regions of biomass burning with large CO concentrations; (1b) regions with few local fire pixels and absence of contributions by transport. Areas with these characteristics include the northeast region of Brazil; (1c) regions close to the source region and strongly affected by transport (region of Para and Amazonas); (2) regions that have a consistent convergence of air masses, that have traveled over biomass burning areas during a few days (western part of the Cerrado region); (3a) Pristine air masses with origin from the ocean; (3b) regions with convergent transport that has passed over areas of no biomass burning, such as frontal weather systems in the southern regions.

  15. First signal from a broadband cryogenic preamplifier cooled by circulating liquid nitrogen in a 7 T Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Choi, Myoung Choul; Lee, Jeong Min; Lee, Se Gyu; Choi, Sang Hwan; Choi, Yeon Suk; Lee, Kyung Jae; Kim, SeungYong; Kim, Hyun Sik; Stahl, Stefan

    2012-12-18

    Despite the outstanding performance of Fourier transform ion cyclotron/mass spectrometry (FTICR/MS), the complexity of the cellular proteome or natural compounds presents considerable challenges. Sensitivity is a key performance parameter of a FTICR mass spectrometer. By improving this parameter, the dynamic range of the instrument can be increased to improve the detection signal of low-abundance compounds or fragment ion peaks. In order to improve sensitivity, a cryogenic detection system was developed by the KBSI (Korean Basic Science Institute) in collaboration with Stahl-Electronics (Mettenheim, Germany). A simple, efficient liquid circulation cooling system was designed and a cryogenic preamplifier implemented inside a FTICR mass spectrometer. This cooling system circulates a cryoliquid from a Dewar to the "liquid circulation unit" through a CF flange to cool a copper block and a cryopreamplifier; the cooling medium is subsequently exhausted into the air. The cryopreamplifier can be operated over a very wide temperature range, from room temperature to low temperature environments (4.2 K). First, ion signals detected by the cryopreamplifier using a circulating liquid nitrogen cooling system were observed and showed a signal-to-noise ratio (S/N) about 130% better than that obtained at room temperature.

  16. Warm-air advection, air mass transformation and fog causes rapid ice melt

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Shupe, Matthew D.; Brooks, Ian M.; Persson, P. Ola G.; Prytherch, John; Salisbury, Dominic J.; Sedlar, Joseph; Achtert, Peggy; Brooks, Barbara J.; Johnston, Paul E.; Sotiropoulou, Georgia; Wolfe, Dan

    2015-07-01

    Direct observations during intense warm-air advection over the East Siberian Sea reveal a period of rapid sea-ice melt. A semistationary, high-pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air-mass transformation over melting sea ice formed a strong, surface-based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface while reducing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m-2 for a week. Satellite images before and after the episode show sea-ice concentrations decreasing from > 90% to ~50% over a large area affected by the air-mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm-air advection.

  17. Variation in summer surface air temperature over Northeast Asia and its associated circulation anomalies

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Hong, Xiaowei; Lu, Riyu; Jin, Aifen; Jin, Shizhu; Nam, Jae-Cheol; Shin, Jin-Ho; Goo, Tae-Young; Kim, Baek-Jo

    2016-01-01

    This study investigates the interannual variation of summer surface air temperature over Northeast Asia (NEA) and its associated circulation anomalies. Two leading modes for the temperature variability over NEA are obtained by EOF analysis. The first EOF mode is characterized by a homogeneous temperature anomaly over NEA and therefore is called the NEA mode. This anomaly extends from southeast of Lake Baikal to Japan, with a central area in Northeast China. The second EOF mode is characterized by a seesaw pattern, showing a contrasting distribution between East Asia (specifically including the Changbai Mountains in Northeast China, Korea, and Japan) and north of this region. This mode is named the East Asia (EA) mode. Both modes contribute equivalently to the temperature variability in EA. The two leading modes are associated with different circulation anomalies. A warm NEA mode is associated with a positive geopotential height anomaly over NEA and thus a weakened upper-tropospheric westerly jet. On the other hand, a warm EA mode is related to a positive height anomaly over EA and a northward displaced jet. In addition, the NEA mode tends to be related to the Eurasian teleconnection pattern, while the EA mode is associated with the East Asia-Pacific/Pacific-Japan pattern.

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

    NASA Astrophysics Data System (ADS)

    Böhme, M.

    2004-05-01

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

  19. The sensitivity of latent heat flux to the air humidity approximations used in ocean circulation models

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Niiler, Pearn P.

    1990-01-01

    In deriving the surface latent heat flux with the bulk formula for the thermal forcing of some ocean circulation models, two approximations are commonly made to bypass the use of atmospheric humidity in the formula. The first assumes a constant relative humidity, and the second supposes that the sea-air humidity difference varies linearly with the saturation humidity at sea surface temperature. Using climatological fields derived from the Marine Deck and long time series from ocean weather stations, the errors introduced by these two assumptions are examined. It is shown that the errors reach above 100 W/sq m over western boundary currents and 50 W/sq m over the tropical ocean. The two approximations also introduce erroneous seasonal and spatial variabilities with magnitudes over 50 percent of the observed variabilities.

  20. Analysis of mass transfer performance in an air stripping tower

    SciTech Connect

    Chung, T.W.; Lai, C.H.; Wu, H.

    1999-10-01

    The carryover of working solution in a traditional stripping tower is of serious concern in real applications. A U-shaped spray tower to prevent carryover has been designed to study the stripping of water vapor from aqueous desiccant solutions of 91.8 to 95.8 wt% triethylene glycol. In this study, water vapor was removed from the diluted desiccant solution by heating the solution and stripping it with the ambient air. Therefore, the solution was concentrated to a desired concentration. This spray tower was capable of handling air flow rates from 3.2 to 5.13 kg/min and liquid flow rates from 1.6 to 2.76 kg/min. Since the literature data on air stripping towers are limited, studies on the mass transfer coefficient and other mass transfer parameters were carried out in this study. Under the operating conditions, the overall mass transfer coefficient calculated from the experimental data varied from 0.053 to 0.169 mol/m{sup 3}{center{underscore}dot}s. These corresponded to heights of a transfer unit of 2.3 to 0.71 m, respectively. The rates of stripping in this spray tower were typically varied from 2.28 to 12.15 kg H{sub 2}O/h. A correlation of the mass transfer coefficient for the air stripping process was also developed in this study.

  1. Water mass circulation on Demerara Rise during the Late Cretaceous based on Nd isotopes

    NASA Astrophysics Data System (ADS)

    Martin, E. E.; MacLeod, K. G.; Jiménez Berrocoso, A.; Bourbon, E.

    2012-04-01

    Circulation in the North Atlantic during the Late Cretaceous has implications for poleward heat transport and nutrient distribution during an extreme greenhouse interval with episodes of ocean anoxia. Nd isotopes of fossil fish teeth and debris represent one of the few water mass tracers that can be used to reconstruct deep ocean circulation. We present Nd isotopic data interpreted as bottom water values for 290 samples from three Ocean Drilling Program sites on Demerara Rise (Sites 1258, 1260, and 1261) along with 102 analyses from four other North Atlantic sites (Cape Verde, Goban Spur, Bermuda Rise and Blake Nose) that provide additional geographic and bathymetric control. Our results confirm the presence of a water mass with low ɛNd values (- 14 to - 17) that are believed to be influenced by continental material during local water mass formation at low latitudes. This Demerara Bottom Water (DBW) is the primary water mass in the region from the Cenomanian to Coniacian and from the late Campanian through early Maastrichtian following a hiatus of ~ 10 my. A positive 8 ɛNd unit excursion occurs during Ocean Anoxic Event 2 (OAE2) that cannot be explained by changes in weathering inputs, diagenesis or magmatic sources of Nd; instead, it appears to represent an influx of bottom waters sourced from the Tethys or North Atlantic. This replacement of DBW during OAE2 argues for decreased production of DBW or enhanced production of Tethys/North Atlantic waters during peak greenhouse conditions. From the late Campanian through early Maastrichtian, DBW becomes the only water mass recorded at Demerara Rise and it appears to expand to abyssal depths at Cape Verde in the Campanian. This water mass is ultimately replaced by waters that appear to be sourced from the North Atlantic starting in the late Maastrichtian. Observed variations in circulation in the tropical North Atlantic during the Late Cretaceous can account for extensive deposition of black shales in the region prior

  2. A heuristic simulation model of Lake Ontario circulation and mass balance transport

    USGS Publications Warehouse

    McKenna, J.E.; Chalupnicki, M.A.

    2011-01-01

    The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

  3. Effects of a Circulating-water Garment and Forced-air Warming on Body Heat Content and Core Temperature

    PubMed Central

    Taguchi, Akiko; Ratnaraj, Jebadurai; Kabon, Barbara; Sharma, Neeru; Lenhardt, Rainer; Sessler, Daniel I.

    2005-01-01

    Background: Forced-air warming is sometimes unable to maintain perioperative normothermia. We therefore compared heat transfer, regional heat distribution, and core rewarming of forced-air warming with a novel circulating-water garment. Methods: Nine volunteers were each evaluated on two randomly ordered study days. They were anesthetized and cooled to a core temperature near 34°C. The volunteers were subsequently warmed for 2.5 hours with either a circulating-water garment or forced-air cover. Overall, heat balance was determined from the difference between cutaneous heat loss (thermal flux transducers) and metabolic heat production (oxygen consumption). Average arm and leg (peripheral) tissue temperatures were determined from 18 intramuscular needle thermocouples, 15 skin thermal flux transducers, and “deep” arm and foot thermometers. Results: Heat production (≈ 60 kcal/h) and loss (≈45 kcal/h) were similar with each treatment before warming. The increase in heat transfer across anterior portions of the skin surface was similar with each warming system (≈65 kcal/h). Forced-air warming had no effect on posterior heat transfer whereas circulating-water transferred 21 ± 9 kcal/h through the posterior skin surface after a half hour of warming. Over 2.5 h, circulating-water thus increased body heat content 56% more than forced air. Core temperatures thus increased faster than with circulating water than forced air, especially during the first hour, with the result that core temperature was 1.1 ± 0.7°C greater after 2.5 h (P < 0.001). Peripheral tissue heat content increased twice as much as core heat content with each device, but the core-to-peripheral tissue temperature gradient remained positive throughout the study. Conclusions: The circulating-water system transferred more heat than forced air, with the difference resulting largely from posterior heating. Circulating water rewarmed patients 0.4°C/h faster than forced air. A substantial peripheral

  4. Small-size mass spectrometer for determining gases and volatile compounds in air during breathing

    NASA Astrophysics Data System (ADS)

    Kogan, V. T.; Kozlenok, A. V.; Chichagov, Yu. V.; Antonov, A. S.; Lebedev, D. S.; Bogdanov, A. A.; Moroshkin, V. S.; Berezina, A. V.; Viktorova-Leclerc, O. S.; Vlasov, S. A.; Tubol'tsev, Yu. V.

    2015-10-01

    We describe an automated mass spectrometer for diagnostics of deceases from the composition of exhaled air. It includes a capillary system, which performs a rapid direct feeding of the sample to the instrument without changing substantially its composition and serves for studying the dynamics of variation of the ratio between various components of exhaled air. The membrane system for introducing the sample is intended for determining low concentrations of volatile organic compounds which are biomarkers of pathologies. It is characterized by selective transmittance and ensures the detection limits of target compounds at the parts per million-parts per billion (ppm-ppb) level. A static mass analyzer operating on permanent magnets possesses advantages important for mobile devices as compared to its dynamic analogs: it is more reliable in operation, has a larger dynamic range, and can be used for determining the concentration of components in the mixture one-by-one or simultaneously. The curvilinear output boundary of the magnetic lens of the mass analyzer makes it possible to reduce its weight and size by 2.5 times without deteriorating the mass resolution. We report on the results of testing of the instrument and consider the possibility of its application for early detection of deceases of respiratory and blood circulation system, gastrointestinal tract, and endocrine system.

  5. Radium mass balance in the Dead Sea - time scale and quantification of circulation in the aquifer

    NASA Astrophysics Data System (ADS)

    Kiro, Y.; Weinstein, Y.; Starinsky, A.; Yechieli, Y.

    2013-12-01

    The Dead Sea hypersaline water and the adjacent groundwater are highly enriched in radium, whose concentration is 2-3 orders of magnitude higher than in the ocean. The combination of carbonate rocks, from which radium is extracted, and the high solubility of radium in hypersaline water contribute these high activities, especially of 226Ra. Being a terminal lake, the Dead Sea concentrates radium mainly the long-lived (t1/2=1600 y) 226Ra isotope, from the surrounding water and groundwater sources. Due to the differences in the isotope half-lives, the shorter-lived isotopes (228Ra, 224Ra and 223Ra) are enriched in the groundwater compared with the lake while 226Ra is enriched both in the lake water (~145 dpm/L) and in the groundwater (up to 500 dpm/L). The 228Ra/226Ra activity ratio in the groundwater on the western shore of the Dead Sea is significantly low (0.03-0.05), representing the high U/Th ratio in the carbonate rocks and sediments around the Dead Sea. However, the high 222Rn activities (up to 60,000 dpm/L) in the groundwater could not be explained by the U content of the carbonate rocks and probably indicate mobility of 226Ra along flow paths where salinity or temperature changes. During Dead Sea water circulation in the aquifer 226Ra is removed from the water by barite precipitation, while 228Ra is added to the water due to recoil from the aquifer sediments. The buildup rate of 228Ra in the circulated Dead Sea water was used for quantifying the circulation rate and the age of the groundwater, while the mass balances of both 228Ra and 226Ra in the lake were used for the quantification of the circulation volume. The rate of Dead Sea water inflow into the aquifer was found to be a few m/y and the annual volume of Dead Sea water circulating in the aquifer is ~320 m3/y. The opposite behavior of 226Ra and 228Ra during the circulation constrains the error on the calculated velocity to be relatively low (ς=×20) and allows the estimation of other sources and sinks

  6. The role of aerosol in altering North Atlantic atmospheric circulation in winter and its impact on air quality

    NASA Astrophysics Data System (ADS)

    Pausata, F. S. R.; Gaetani, M.; Messori, G.; Kloster, S.; Dentener, F. J.

    2015-02-01

    Numerical model scenarios of future climate depict a global increase in temperatures and changing precipitation patterns, primarily driven by increasing greenhouse gas (GHG) concentrations. Aerosol particles also play an important role by altering the Earth's radiation budget and consequently surface temperature. Here, we use the general circulation aerosol model ECHAM5-HAM, coupled to a mixed layer ocean model, to investigate the impacts of future air pollution mitigation strategies in Europe on winter atmospheric circulation over the North Atlantic. We analyse the extreme case of a maximum feasible end-of-pipe reduction of aerosols in the near future (2030), in combination with increasing GHG concentrations. Our results show a more positive North Atlantic Oscillation (NAO) mean state by 2030, together with a significant eastward shift of the southern centre of action of sea-level pressure (SLP). Moreover, we show a significantly increased blocking frequency over the western Mediterranean. By separating the impacts of aerosols and GHGs, our study suggests that future aerosol abatement may be the primary driver of both the eastward shift in the southern SLP centre of action and the increased blocking frequency over the western Mediterranean. These concomitant modifications of the atmospheric circulation over the Euro-Atlantic sector lead to more stagnant weather conditions that favour air pollutant accumulation, especially in the western Mediterranean sector. Changes in atmospheric circulation should therefore be included in future air pollution mitigation assessments. The indicator-based evaluation of atmospheric circulation changes presented in this work will allow an objective first-order assessment of the role of changes in wintertime circulation on future air quality in other climate model simulations.

  7. Analytical model for contaminant mass removal by air sparging

    SciTech Connect

    Rabideau, A.J.; Blayden, J.M.

    1998-12-31

    An analytical model was developed to predict the removal of volatile organic compounds (VOCs) from ground water by air sparging (AS). The model treats the air sparging zone as a completely mixed reactor subject to the removal of dissolved contaminants by volatilization, advection, and first-order decay. Nonequilibrium desorption is approximated as a first-order mass transfer process. The model reproduces the tailing and rebound behavior often observed at AS sites, and would normally require the estimation of three site-specific parameters. Dimensional analysis demonstrates that predicting tailing can be interpreted in terms of kinetic desorption or diffusion of aqueous phase contaminants into discrete air channels. Related work is ongoing to test the model against field data.

  8. The mass and speed dependence of meteor air plasma temperatures.

    PubMed

    Jenniskens, Peter; Laux, Christophe O; Wilson, Michael A; Schaller, Emily L

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  9. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  10. Solomon Sea circulation and water mass modifications: response at ENSO timescales

    NASA Astrophysics Data System (ADS)

    Melet, Angélique; Gourdeau, Lionel; Verron, Jacques; Djath, Bughsin

    2013-01-01

    The South Pacific low latitude western boundary currents (LLWBCs) carry waters of subtropical origin through the Solomon Sea before joining the equatorial Pacific. Changes in their properties or transport are assumed to impact El Niño Southern Oscillation (ENSO) dynamics. At ENSO timescales, the LLWBCs transport tends to counterbalance the interior geostrophic one. When transiting through the complex geography of the Solomon Sea, the main LLWBC, the New Guinea Coastal Undercurrent, cannot follow a unique simple route to the equator. Instead, its routes and water mass properties are influenced by the circulation occurring in the Solomon Sea. In this study, the response of the Solomon Sea circulation to ENSO is investigated based on a numerical simulation. The transport anomalies entering the Solomon Sea from the south are confined to the top 250 m of the water column, where they represent 7.5 Sv (based on ENSO composites) for a mean transport of 10 Sv. The induced circulation anomalies in the Solomon Sea are not symmetric between the two ENSO states because of (1) a bathymetric control at Vitiaz Strait, which plays a stronger role during El Niño, and (2) an additional inflow through Solomon Strait during La Niña events. In terms of temperature and salinity, modifications are particularly notable for the thermocline water during El Niño conditions, with cooler and fresher waters compared to the climatological mean. The surface water at Vitiaz Strait and the upper thermocline water at Solomon Strait, feeding respectively the equatorial Pacific warm pool and the Equatorial Undercurrent, particularly affect the heat and salt fluxes. These fluxes can change by up to a factor of 2 between extreme El Niño and La Niña conditions.

  11. The Theory of Propellers I : Determination of the Circulation Function and the Mass Coefficient for Dual-Rotating Propellers

    NASA Technical Reports Server (NTRS)

    Theodorsen, Theodore

    1944-01-01

    Values of the circulation function have been obtained for dual-rotating propellers. Numerical values are given for four, eight, and twelve-blade dual-rotating propellers and for advance ratios from 2 to about 6. In addition, the circulation function has been determine for single-rotating propellers for the higher values of the advance ratio. The mass coefficient, another quantity of significance in propeller theory, has been introduced.

  12. Decadal slowdown in global air temperature rise triggered by variability in the Atlantic Meridional Overturning Circulation

    NASA Astrophysics Data System (ADS)

    England, Matthew H.

    2015-04-01

    Various explanations have been proposed for the recent slowdown in global surface air temperature (SAT) rise, either involving enhanced ocean heat uptake or reduced radiation reaching Earth's surface. Among the mechanisms postulated involving enhanced ocean heat uptake, past work has argued for both a Pacific and Atlantic origin, with additional contributions from the Southern Ocean. Here we examine the mechanisms driving 'hiatus' periods originating out of the Atlantic Ocean. We show that while Atlantic-driven hiatuses are entirely plausible and consistent with known climate feedbacks associated with variability in the Atlantic Meridional Overturning Circulation (AMOC), the present climate state is configured to enhance global-average SAT, not reduce it. We show that Atlantic hiatuses are instead characterised by anomalously cool fresh oceanic conditions in the North Atlantic, with the atmosphere advecting the cool temperature signature zonally. Compared to the 1980s and 1990s, however, the mean climate since 2001 has been characterised by a warm saline North Atlantic, suggesting the AMOC cannot be implicated as a direct driver of the current hiatus. We further discuss the impacts of a warm tropical Atlantic on the unprecedented trade wind acceleration in the Pacific Ocean, and propose that this is the main way that the Atlantic has contributed to the present "false pause" in global warming.

  13. Air Mass Origin in the Arctic and its Response to Future Warming

    NASA Astrophysics Data System (ADS)

    Orbe, C.; Newman, P. A.; Waugh, D. W.; Holzer, M. B.; Oman, L.; Polvani, L. M.; Li, F.

    2014-12-01

    Long-range transport from Northern Hemisphere (NH) midlatitudes plays a key role in setting the distributions of trace species and aerosols in the Arctic. While comprehensive models project a strengthening and poleward shift in the midlatitude tropospheric jets in response to future warming, relatively little attention has been paid to assessing the large-scale transport response in the Arctic. A natural way to quantify transport and its future changes is in terms of rigorously defined air masses that partition air according to where it last contacted the planetary boundary layer (PBL). Here we present climatologies of Arctic air mass origin for NH winter and summer, computed from two integrations of the Goddard Earth Observing System chemistry-climate model (GEOSCCM) subject to present-day and future climate forcings. The modeled transport response to A1B greenhouse-gas induced warming reveals that in the future ~10% more air in the Arctic will originate over NH midlatitudes, with a slighter weaker albeit significant increase in winter compared to summer. Our results indicate that transport changes alone may lead to "cleaner" Arctic winters, as air will be 5-10% more likely to have last contacted the PBL over the East Pacific and the Atlantic Oceans and less likely to have originated over Europe and North America. Conversely, in future summers the air mass fractions originating over Asia and North America increase by ~10%, indicating that Arctic pollutant levels may be enhanced owing solely to changes in transport. In particular, our results suggest that more stringent emissions caps may be needed to combat enhanced transport into the Arctic from Asia, where increases in black carbon emissions have already posed concerns. Future changes in air mass fractions are interpreted in terms of large-scale circulation responses that are consistent with CMIP5 multi-model mean projections - namely, upward and poleward shifted meridional transient eddies in future winters and

  14. On the origin and destination of atmospheric moisture and air mass over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xu, Xiang-De; Yang, Shuai; Zhang, Wei

    2012-12-01

    The Tibet Plateau (TP) is a key region that imposes profound impacts on the atmospheric water cycle and energy budget of Asia, even the global climate. In this work, we develop a climatology of origin (destination) of air mass and moisture transported to (from) the TP using a Lagrangian moisture diagnosis combined with the forward and backward atmospheric tracking schemes. The climatology is derived from 6-h particle positions based on 5-year (2005-2009) seasonal summer trajectory dataset from the Lagrangian particle dispersion model FLEXPART using NCEP/GFS data as input, where the regional model atmosphere was globally filled with particles. The results show that (1) the dominant origin of the moisture supplied to the TP is a narrow tropical-subtropical band in the extended Arabian Sea covering a long distance from the Indian subcontinent to the Southern Hemisphere. Two additional moisture sources are located in the northwestern part of TP and the Bay of Bengal and play a secondary role. This result indicates that the moisture transporting to the TP more depends on the Indian summer monsoon controlled by large-scale circulation. (2) The moisture departing from the TP can be transported rapidly to East Asia, including East China, Korea, Japan, and even East Pacific. The qualitative similarity between the regions of diagnosed moisture loss and the pattern of the observed precipitation highlights the robustness of the role of the TP on precipitation over East Asia. (3) In contrast to the moisture origin confined in the low level, the origin and fate of whole column air mass over the TP is largely controlled by a strong high-level Asian anticyclone. The results show that the TP is a crossroad of air mass where air enters mainly from the northwest and northeast and continues in two separate streams: one goes southwestwards over the Indian Ocean and the other southeastwards through western North Pacific. Both of them partly enter the trade wind zone, which manifests the

  15. Functional forms for approximating the relative optical air mass

    NASA Astrophysics Data System (ADS)

    Rapp-Arrarás, Ígor; Domingo-Santos, Juan M.

    2011-12-01

    This article constitutes a review and systematic comparison of functional forms for approximating the air mass from the zenith to the horizon. Among them, we find the most meaningful forms in atmospheric optics, geophysics, meteorology, and solar energy science, as well as several forms arising from the study of the atmospheric delay of electromagnetic signals, whose relationship with the air mass was recently proved by the authors. In total, we have compared 26 functional forms, and the fits have been done for three atmospheric profiles, an observer at sea level, and the median wavelength of the Sun's spectral irradiance (0.7274 μm). As a result, the best of the uniparametric forms has more than three centuries of history; the best of the biparametric forms was recently introduced by one of the authors; the best of the tri- and tetraparametric forms were originally proposed for modeling the atmospheric delay of radio signals; and the best of the forms with more than four parameters is used here for the first time. On the basis of these, for the 1976 U.S. Standard Atmosphere (USSA-76), we provide one-, two-, three-, four-, and five-parameter formulas whose maximum deviations are 1.70, 2.91 × 10-1, 3.28 × 10-2, 2.49 × 10-3, and 3.24 × 10-4, respectively.

  16. Experimental determination of the effect of mountain-valley breeze circulation on air pollution in the vicinity of Freiburg

    NASA Astrophysics Data System (ADS)

    Baumbach, Günter; Vogt, Ulrich

    Tethersonde and airship measurements were carried out in 1994 during two different seasons within the framework of the preparation of the Clean Air Plan of Freiburg. These investigations concerned the influence of the Freiburg mountain-valley wind system, the so-called Höllentäler, on Freiburg's air quality. Vertical and horizontal measurements carried out east of Freiburg in the Dreisam Valley revealed that when the mountain-valley wind system has developed during summer high-pressure weather conditions, Freiburg is supplied with low polluted air masses from the Black Forest at night up to the early morning hours. Conversely, it may occur that during stable weather conditions with low wind speeds, the polluted air masses which flow into the Black Forest during the day are transported back to Freiburg with the mountain wind, so that there is no fresh air supply.

  17. Maternal Body-Mass Index and Cord Blood Circulating Endothelial Colony-Forming Cells

    PubMed Central

    Lin, Ruei-Zeng; Miranda, Maria L.; Vallejo-Vaz, Antonio J.; Stiefel, Pablo; Praena-Fernández, Juan M.; Bernal-Bermejo, Jose; Jimenez-Jimenez, Luis M.; Villar, Jose; Melero-Martin, Juan M.

    2013-01-01

    Objective Endothelial colony-forming cells (ECFCs) are a subset of circulating endothelial progenitor cells that are particularly abundant in umbilical cord blood. We sought to determine whether ECFC abundance in cord blood is associated with maternal body-mass index (BMI) in non-pathological pregnancies. Study design We measured the level of ECFCs in the cord blood of neonates (n=27) born from non-obese healthy mothers with non-pathological pregnancies and examined whether ECFC abundance correlated with maternal BMI. We also examined the effect of maternal BMI on ECFC phenotype and function using angiogenic and vasculogenic assays. Results We observed variation in ECFC abundance among subjects and found a positive correlation between pre-pregnancy maternal BMI and ECFC content (r=0.51, P=0.007), which was independent of other obstetric factors. Despite this variation, ECFC phenotype and functionality were deemed normal and highly similar between subjects with maternal BMI <25 kg/m2 and BMI between 25–30 kg/m2, including the ability to form vascular networks in vivo. Conclusions This study underlines the need to consider maternal BMI as a potential confounding factor for cord blood levels of ECFCs in future comparative studies between healthy and pathological pregnancies. Endothelial colony-forming cells (ECFCs) are a subset of progenitor cells that circulate in peripheral blood and can give rise to endothelial cells (1,2), contributing to the formation of new vasculature and the maintenance of vascular integrity (3–5). The mechanisms that regulate the abundance of these cells in vivo remain poorly understood. ECFCs are rare in adult peripheral blood (1,2,10). In contrast, there is an elevated number of these cells in fetal blood during the third trimester of pregnancy (11–13). Emerging evidence indicates that deleterious conditions during fetal life can impair ECFC content and function. For instance, offspring of diabetic mothers have been shown to have

  18. High-Altitude Air Mass Zero Calibration of Solar Cells

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Snyder, David B.

    2005-01-01

    Air mass zero calibration of solar cells has been carried out for several years by NASA Glenn Research Center using a Lear-25 aircraft and Langley plots. The calibration flights are carried out during early fall and late winter when the tropopause is at the lowest altitude. Measurements are made starting at about 50,000 feet and continue down to the tropopause. A joint NASA/Wayne State University program called Suntracker is underway to explore the use of weather balloon and communication technologies to characterize solar cells at elevations up to about 100 kft. The balloon flights are low-cost and can be carried out any time of the year. AMO solar cell characterization employing the mountaintop, aircraft and balloon methods are reviewed. Results of cell characterization with the Suntracker are reported and compared with the NASA Glenn Research Center aircraft method.

  19. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  20. Ambient particulate air pollution and circulating antioxidant enzymes: A repeated-measure study in healthy adults in Beijing, China.

    PubMed

    Wu, Shaowei; Wang, Bin; Yang, Di; Wei, Hongying; Li, Hongyu; Pan, Lu; Huang, Jing; Wang, Xin; Qin, Yu; Zheng, Chanjuan; Shima, Masayuki; Deng, Furong; Guo, Xinbiao

    2016-01-01

    The association of systemic antioxidant activity with ambient air pollution has been unclear. A panel of 40 healthy college students underwent repeated blood collection for 12 occasions under three exposure scenarios before and after relocating from a suburban area to an urban area in Beijing, China in 2010-2011. We measured various air pollutants including fine particles (PM2.5) and determined circulating levels of antioxidant enzymes extracellular superoxide dismutase (EC-SOD) and glutathione peroxidase 1 (GPX1) in the laboratory. An interquartile range increase of 63.4 μg/m(3) at 3-d PM2.5 moving average was associated with a 6.3% (95% CI: 0.6, 12.4) increase in EC-SOD and a 5.5% (95% CI: 1.3, 9.8) increase in GPX1. Several PM2.5 chemical constituents, including negative ions (nitrate and chloride) and metals (e.g., iron and strontium), were consistently associated with increases in EC-SOD and GPX1. Our results support activation of circulating antioxidant enzymes following exposure to particulate air pollution.

  1. A History of Water Mass Circulation in the Paleogene Southern Ocean from Nd Isotopes

    NASA Astrophysics Data System (ADS)

    Scher, H. D.; Martin, E. E.

    2003-12-01

    Using fossil fish teeth from ODP site 689 (2080m, Maud Rise) we have generated a 28 Myr record of Nd isotope ratios and concentrations for the early middle Eocene to early Miocene at an average resolution of 250-300 kyr. ɛ Nd(T) values documented in this time series range from -9.5 to -7.35, and demonstrate a pattern of secular variations that is remarkably similar to benthic foraminiferal δ 13C records from this site. This correlation suggests that secular variations of ɛ Nd(T) values observed at site 689 are related to changes in ocean circulation and may provide insight into the history of water mass circulation in the Southern Ocean. Early middle Eocene ɛ Nd(T) values average -9.25 and display little variation compared to younger portions of the record, which illustrate long term oscillations beginning in the late middle Eocene. Starting at 40.8 Ma ɛ Nd(T) values increase over a 6 Myr interval from -9.4 to -7.35 in a stepwise fashion. Although ɛ Nd(T) values begin to rise during the late middle Eocene the period of most rapid change occurs in the late Eocene (after 37 Ma). ɛ Nd(T) values begin to fall in the earliest Oligocene reaching -8.75 at 30 Ma, then rise to -7.75 during the late Oligocene, but fall again to -8.75 by the end of the Oligocene. A hiatus occurs from the latest Oligocene to early Miocene. Following that interval, late early Miocene values average -8.5. Throughout the record the most radiogenic Nd isotopic compositions ( ˜ -7.5), are associated with high δ 13C values (1.2-1.4 ‰ ), while nonradiogenic Nd isotopic compositions are associated with lower δ 13C values (.2-.4 ‰ ). The subsidence curve constructed for site 689 indicates a middle Eocene paleodepth of 1200-1500 m. A mean ɛ Nd(T) value of -9.25 during the middle Eocene possibly reflects upward mixing of Warm Saline Deep Water (WSDW) from the Tethys Sea, which has been documented at a deeper site on the Maud Rise (690) on the basis of an oxygen isotopic inversion between

  2. Influence of Baseline Air Masses and Wildland Fires on Air Quality in the Western United States

    NASA Astrophysics Data System (ADS)

    Wigder, Nicole L.

    This dissertation focuses on several key uncertainties related to particulate matter (PM) and O3 concentrations in the western U.S. Each analysis conducted for this dissertation centers on data collected at the Mount Bachelor Observatory (MBO, 2.8 km a.s.l., 43.98° N, 121.69° W), a mountaintop research site in central Oregon, U.S. The first component of this dissertation is an analysis of the contribution of baseline O3 to observed O3 concentrations in two western U.S. urban areas, Enumclaw, Washington (WA) and Boise, Idaho, during 2004 -- 2010. I compared O3 data from two baseline sites (MBO and Cheeka Peak, WA) to O3 concentrations in the two urban areas on days when backward air mass trajectories showed transport between the baseline and urban sites. I found that the urban areas studied had relatively low O3 on the days with a strong influence from baseline air masses (28.3 -- 48.3 ppbv). These data suggested that there was low production of O3 from urban emissions on these days, which allowed me to quantify the impact of baseline O3 on urban O3 concentrations. A regression of the Boise and MBO O3 observations showed that free tropospheric air masses were diluted by 50% as they were entrained into the boundary layer at Boise. These air masses can contain high O3 concentrations (>70 ppbv) from Asian pollution sources or stratospheric intrusions, indicating that these sources can greatly contribute to urban surface O 3 concentrations. In addition, I found that the elevation and surface temperature of the urban areas studied impacted baseline O3 concentrations in these areas, with higher elevation and greater surface temperatures leading to greater O3 concentrations. The second and third components of this dissertation are analyses of the impact of wildland fires on PM and O3 concentrations in the western U.S. For both of these analyses, I calculated pollutant enhancement ratios for PM, O3, and other species in wildland fire plumes observed at MBO during 2004

  3. Mass transfer of VOCs in laboratory-scale air sparging tank.

    PubMed

    Chao, Keh-Ping; Ong, Say Kee; Huang, Mei-Chuan

    2008-04-15

    Volatilization of VOCs was investigated using a 55-gal laboratory-scale model in which air sparging experiments were conducted with a vertical air injection well. In addition, X-ray imaging of an air sparging sand box showed air flows were in the form of air bubbles or channels depending on the size of the porous media. Air-water mass transfer was quantified using the air-water mass transfer coefficient which was determined by fitting the experimental data to a two-zone model. The two-zone model is a one-dimensional lumped model that accounts for the effects of air flow type and diffusion of VOCs in the aqueous phase. The experimental air-water mass transfer coefficients, KGa, obtained from this study ranged from 10(-2) to 10(-3)1/min. From a correlation analysis, the air-water mass transfer coefficient was found to be directly proportional to the air flow rate and the mean particle size of soil but inversely proportional to Henry's constant. The correlation results implied that the air-water mass transfer coefficient was strongly affected by the size of porous media and the air flow rates. PMID:17804158

  4. Changing air mass frequencies in Canada: potential links and implications for human health.

    PubMed

    Vanos, J K; Cakmak, S

    2014-03-01

    Many individual variables have been studied to understand climate change, yet an overall weather situation involves the consideration of many meteorological variables simultaneously at various times diurnally, seasonally, and yearly. The current study identifies a full weather situation as an air mass type using synoptic scale classification, in 30 population centres throughout Canada. Investigative analysis of long-term air mass frequency trends was completed, drawing comparisons between seasons and climate zones. We find that the changing air mass trends are highly dependent on the season and climate zone being studied, with an overall increase of moderate ('warm') air masses and decrease of polar ('cold') air masses. In the summertime, general increased moisture content is present throughout Canada, consistent with the warming air masses. The moist tropical air mass, containing the most hot and humid air, is found to increase in a statistically significant fashion in the summertime in 46% of the areas studied, which encompass six of Canada's ten largest population centres. This emphasises the need for heat adaptation and acclimatisation for a large proportion of the Canadian population. In addition, strong and significant decreases of transition/frontal passage days were found throughout Canada. This result is one of the most remarkable transition frequency results published to date due to its consistency in identifying declining trends, coinciding with research completed in the United States (US). We discuss relative results and implications to similar US air mass trend analyses, and draw upon research studies involving large-scale upper-level air flow and vortex connections to air mass changes, to small-scale meteorological and air pollution interactions. Further research is warranted to better understand such connections, and how these air masses relate to the overall and city-specific health of Canadians.

  5. Analysis of long-range transport of particulate matters in connection with air circulation over Central and Eastern part of Europe

    NASA Astrophysics Data System (ADS)

    Stefan, Sabina; Necula, Cristian; Georgescu, Florinela

    The aim of this paper is to establish a practical methodology for examining the long-range transport of particulate matters (PM), named TSP. The daily concentration values of TSP from years 2001 and 2002, for three sites, Baia Mare (RO), Vienna (AU), Aosta (IT), were analyzed. In order to connect the main air circulation types with the aerosol concentrations at the selected sites, the catalogues of Circulation and Weather type Classification (COST733) were used. Spectral analysis was made using spectrum software based on Lomb-Scargle periodograms, and multiresolution analysis (MRA) technique based on Maximal Overlap Discrete Wavelet Transform (MODWT) with Fejer-Korovkin in 22 points wavelet filter (waveslim package). Spectral analysis shows a dominant one-year periodicity for all the time series with a variance around 22% for each time series. In addition, several winters TSP pollution episodes from each city were analyzed using a back trajectory model (HYSPLIT4), in order to compare with the resulted air circulation types. Two important concluding remarks emerge: (i) the Eastern part of Europe shows a dominant easterly air circulation and central Europe is characterized by south-west air circulations, which drive the maxima of pollutant concentrations; (ii) the choice of the domain for analysis of the circulation types is very important.

  6. Microbial air quality in mass transport buses and work-related illness among bus drivers of Bangkok Mass Transit Authority.

    PubMed

    Luksamijarulkul, Pipat; Sundhiyodhin, Viboonsri; Luksamijarulkul, Soavalug; Kaewboonchoo, Orawan

    2004-06-01

    The air quality in mass transport buses, especially air-conditioned buses may affect bus drivers who work full time. Bus numbers 16, 63, 67 and 166 of the Seventh Bus Zone of Bangkok Mass Transit Authority were randomly selected to investigate for microbial air quality. Nine air-conditioned buses and 2-4 open-air buses for each number of the bus (36 air-conditioned buses and 12 open-air buses) were included. Five points of in-bus air samples in each studied bus were collected by using the Millipore A ir Tester Totally, 180 and 60 air samples collected from air-conditioned buses and open-air buses were cultured for bacterial and fungal counts. The bus drivers who drove the studied buses were interviewed towards histories of work-related illness while working. The results revealed that the mean +/- SD of bacterial counts in the studied open-air buses ranged from 358.50 +/- 146.66 CFU/m3 to 506 +/- 137.62 CFU/m3; bus number 16 had the highest level. As well as the mean +/- SD of fungal counts which ranged from 93.33 +/- 44.83 CFU/m3 to 302 +/- 294.65 CFU/m3; bus number 166 had the highest level. Whereas, the mean +/- SD of bacterial counts in the studied air-conditioned buses ranged from 115.24 +/- 136.01 CFU/m3 to 244.69 +/- 234.85 CFU/m3; bus numbers 16 and 67 had the highest level. As well as the mean +/- SD of fungal counts which rangedfrom 18.84 +/- 39.42 CFU/m3 to 96.13 +/- 234.76 CFU/m3; bus number 166 had the highest level. When 180 and 60 studied air samples were analyzed in detail, it was found that 33.33% of the air samples from open-air buses and 6.11% of air samples from air-conditioned buses had a high level of bacterial counts (> 500 CFU/m3) while 6.67% of air samples from open-air buses and 2.78% of air samples from air-conditioned buses had a high level of fungal counts (> 500 CFU/m3). Data from the history of work-related illnesses among the studied bus drivers showed that 91.67% of open-air bus drivers and 57.28% of air-conditioned bus drivers had

  7. Air pollution exposure affects circulating white blood cell counts in healthy subjects: the role of particle composition, oxidative potential and gaseous pollutants - the RAPTES project.

    PubMed

    Steenhof, Maaike; Janssen, Nicole A H; Strak, Maciej; Hoek, Gerard; Gosens, Ilse; Mudway, Ian S; Kelly, Frank J; Harrison, Roy M; Pieters, Raymond H H; Cassee, Flemming R; Brunekreef, Bert

    2014-02-01

    Studies have linked air pollution exposure to cardiovascular health effects, but it is not clear which components drive these effects. We examined the associations between air pollution exposure and circulating white blood cell (WBC) counts in humans. To investigate independent contributions of particulate matter (PM) characteristics, we exposed 31 healthy volunteers at five locations with high contrast and reduced correlations amongst pollutant components: two traffic sites, an underground train station, a farm and an urban background site. Each volunteer visited at least three sites and was exposed for 5 h with intermittent exercise. Exposure measurements on-site included PM mass and number concentration, oxidative potential (OP), elemental- and organic carbon, metals, O3 and NO2. Total and differential WBC counts were performed on blood collected before and 2 and 18 h post-exposure (PE). Changes in total WBC counts (2 and 18 h PE), number of neutrophils (2 h PE) and monocytes (18 h PE) were positively associated with PM characteristics that were high at the underground site. These time-dependent changes reflect an inflammatory response, but the characteristic driving this effect could not be isolated. Negative associations were observed for NO2 with lymphocytes and eosinophils. These associations were robust and did not change after adjustment for a large suite of PM characteristics, suggesting an independent effect of NO2. We conclude that short-term air pollution exposure at real-world locations can induce changes in WBC counts in healthy subjects. Future studies should indicate if air pollution exposure-induced changes in blood cell counts results in adverse cardiovascular effects in susceptible individuals.

  8. Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2012-12-01

    While the isotopic distribution of precipitation has been widely used for research in hydrology, paleoclimatology, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal

  9. Influence of sea ice cover and icebergs on circulation and water mass formation in a numerical circulation model of the Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Dinniman, Michael S.; Klinck, John M.; Smith, Walker O.

    2007-11-01

    Satellite imagery shows that there was substantial variability in the sea ice extent in the Ross Sea during 2001-2003. Much of this variability is thought to be due to several large icebergs that moved through the area during that period. The effects of these changes in sea ice on circulation and water mass distributions are investigated with a numerical general circulation model. It would be difficult to simulate the highly variable sea ice from 2001 to 2003 with a dynamic sea ice model since much of the variability was due to the floating icebergs. Here, sea ice concentration is specified from satellite observations. To examine the effects of changes in sea ice due to iceberg C-19, simulations were performed using either climatological ice concentrations or the observed ice for that period. The heat balance around the Ross Sea Polynya (RSP) shows that the dominant term in the surface heat budget is the net exchange with the atmosphere, but advection of oceanic warm water is also important. The area average annual basal melt rate beneath the Ross Ice Shelf is reduced by 12% in the observed sea ice simulation. The observed sea ice simulation also creates more High-Salinity Shelf Water. Another simulation was performed with observed sea ice and a fixed iceberg representing B-15A. There is reduced advection of warm surface water during summer from the RSP into McMurdo Sound due to B-15A, but a much stronger reduction is due to the late opening of the RSP in early 2003 because of C-19.

  10. Midlatitudes precipitation and the global atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Pauluis, O.; Czaja, A.; Korty, R.; Laliberte, F.

    2008-12-01

    The global atmospheric circulation transports energy from the equatorial regions to higher latitudes. Due to the turbulent nature of the flow, describing a 'mean' circulation depends strongly on the averaging method and coordinates system. When averaged in isentropic coordinates, the circulation appears as a single overturning cell with a poleward flow of high entropy air and return flow at lower entropy. However, the entropy of a parcel of moist air is not uniquely defined, and different expression for the entropy yield different mean circulations. Here, the global circulation in the NCEP/NCAR Reanalysis is computed on surfaces of constant potential temperature, or dry isentropes, and on surfaces of constant equivalent potential temperature, or moist isentropes. The two analyses are qualitatively similar but differ quantitatively in that the circulation on moist isentropes is between 1.5 and 3 times larger than the circulation on dry isentropes. It is shown that the additional mass transport on moist isentropes corresponds to a poleward flow of warm, moist air near the Earth's surface that moves from the subtropics into the midlatitudes and rises in the upper troposphere within the stormtracks. In the subtropics, this flow is characterized by a low potential temperature but a much higher equivalent potential temperature. It does not appear in the circulation on dry isentropes, as it is hidden by the presence of a larger equatorward flow of drier air at same potential temperature. However, as the equivalent potential temperature in this low-level poleward flow is close to the potential temperature of the air near the tropopause, it is included in the total circulation on moist isentropes. The thermodynamic properties of this low-level poleward flow indicates that these poleward moving air parcels should ascend into the upper troposphere within the midlatitude stormtracks. Based on these findings, we propose a revised version of the global circulation. We argue that

  11. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    NASA Technical Reports Server (NTRS)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; Diskin, Glenn S.; Dickerson, Russell R.

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  12. Water mass circulation on the continental shelf of the Gulf of Cádiz

    NASA Astrophysics Data System (ADS)

    García-Lafuente, Jesús; Delgado, Javier; Criado-Aldeanueva, Francisco; Bruno, Miguel; del Río, Jorge; Miguel Vargas, Juan

    2006-06-01

    Acoustic Doppler Current Profiler data collected during three successive surveys in the Gulf of Cádiz in May-June 2001 have been used to analyse the surface circulation on the continental shelves of the Gulf of Cádiz and how this circulation matches the circulation in the ocean side of the Gulf. The wider and larger eastern continental shelf holds a cyclonic circulation bounded at the south by a shelf-break jet that is identified with the Huelva front. The coastal current that closes the gyre at the north is identified with the warm counterflow mentioned in the literature. Under westerly winds, this counter current recirculates toward the east while recent upwelled water near Cape Santa Maria is advected downstream by the shelf-break jet, leaving the cold signature at the surface that has been identified historically with the Huelva front. Under easterlies, part of the coastal counterflow invades the western continental shelf while the remaining recirculates eastward to close the cyclonic cell. The western continental shelf and slope is occupied by a larger-scale cyclonic eddy that extends into the deep ocean. This eddy has vertical length scale of hundreds of metres and is linked to the general wind forcing in the area. Both cyclonic structures are bounded at the south by a jet that enters in the Gulf of Cádiz moving around the second eddy and eastward to feed the Atlantic inflow through the Strait of Gibraltar.

  13. Mathematical modeling of heat exchange between mine air and rock mass during fire

    SciTech Connect

    A.E. Krasnoshtein; B.P. Kazakov; A.V. Shalimov

    2006-05-15

    Solution of problems on heat exchange between ventilating air and rock mass and on gas admixture propagation in mine workings serve as a base for considering changes in heat-gas-air state at a mine after inflammation. The presented mathematical relations allow calculation of a varied velocity and movement direction of air flows, their temperatures and smoking conditions during fire.

  14. DNS of scalar transfer across an air-water interface during inception and growth of Langmuir circulation

    NASA Astrophysics Data System (ADS)

    Hafsi, Amine; Tejada-Martinez, Andres; Veron, Fabrice; Ma, Yi; USF/UDEL Collaboration

    2015-11-01

    Upon a blowing of a wind over an initially quiescent air-sea interface, first short capillary waves are generated which in time coexist with longer waves as part of a broad spectrum of waves. The interaction between the Stokes drift velocity induced by surface gravity waves and the mean current induced by surface wind stress leads to Langmuir turbulence (LT) characterized by Langmuir circulation (LC) consisting of parallel downwind-elongated, counter rotating vortices roughly aligned in the direction of the wind. The typical length scale of LC ranges from several centimeters when short capillary waves first appear up to tens of meters when the spectrum of waves broadens. Results are presented from direct numerical simulation (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s. Cases with a freely deforming interface (characterized by gravity-capillary waves giving rise to small-scale LC) and with the interface intentionally held fixed (i.e. without LC) will be compared to understand the mechanisms by which the LT enhances scalar transfer from the airside to the waterside and bulk concentration throughout the water column. Time-permitting, we will compare our results with available laboratory physical experiments.

  15. View-Angle Dependent AIRS Cloud Radiances and Fluctuations: Implications of Organized Cloud Structures for Tropical Circulations

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.; Gong, Jie

    2012-01-01

    Interactions between wave dynamics and moisture generate clouds in a wide range of scales. Organized cloud structures produce statistically asymmetric radiances and perturbations in AIRS and AMSU-B measurements. With high resolution (approx.14 km beamwidth) and high-sensitivity instruments, these wave-modulated cloud structures can be readily detected from calibrated Levell radiance data. In this study we analyzed eight-year (2003 - 2010) statistics of AIRS cloud-induced radiances and found that in tropical convective regions the ascending (13:30 LST) measurements reveal higher view-angle asymmetry in cloud radiance than the descending (1:30 LST). The daytime asymmetry suggests 10% more cloudiness when the instrument views east, implying tilted and banded structures in most of the anvil clouds to which AIRS is sensitive. Such banded cloud structures are likely a manifestation of embedded westward propagating gravity waves in tropical convective systems. More importantly, organized cloud structures carry asymmetric momentum fluxes in addition to energy fluxes, which must be taken into account for modeling wave-wave and wave-mean flow interactions in tropical circulations.

  16. Air Mass Origin as a Diagnostic of Seasonally-Varying Transport into the Arctic

    NASA Astrophysics Data System (ADS)

    Orbe, C.; Waugh, D. W.; Holzer, M. B.; Newman, P. A.; Polvani, L. M.; Oman, L.; Li, F.

    2013-12-01

    While the signatures of the seasonal cycle on basic state variables such as temperature, winds and on chemical composition have been explored in depth, its signature on air mass composition has received relatively little attention. To this end, we present the first analysis of the seasonally varying transport from the northern hemisphere (NH) midlatitudes into the Arctic using rigorously defined air masses. The fractional contribution from each air mass partitions Arctic air according to where it was last in the planetary boundary layer (PBL) at midlatitudes over the Pacific and Atlantic oceans, North America, Europe, and Asia. Air mass fractions are computed using the coupled climate-chemistry model GEOSCCM subject to fixed present-day climate forcings. We find that during DJF 48% of the air in the free troposphere poleward of 60N was last at midlatitudes primarily at the Pacific and Atlantic oceans, at 20% and 10% respectively. During JJA, however, the largest contributions to Arctic air come from Asian and North American source regions, revealing that transport from the industrialized midlatitude regions dominates during boreal summer. Preliminary calculations of future air masses for a model integration subject to A1B greenhouse gases also reveal the model's climate change response in arctic air mass composition. In concert with weakened tropospheric eddy kinetic energy and a weakened Hadley cell, we find that changes in annual mean arctic air mass fractions are of the order 10%, with increased contributions from air that was last in contact with the PBL over North America and over the Atlantic and Pacific oceans. Air-mass fractions, and their changes, thus help to isolate the role of transport to changes in composition, which are not only driven by changes in chemistry and emissions but also crucially by changes in atmospheric flow.

  17. CFD analyses of natural circulation in the air-cooled reactor cavity cooling system

    SciTech Connect

    Hu, R.; Pointer, W. D.

    2013-07-01

    The Natural Convection Shutdown Heat Removal Test Facility (NSTF) is currently being built at Argonne National Laboratory, to evaluate the feasibility of the passive Reactor Cavity Cooling System (RCCS) for Next Generation Nuclear Plant (NGNP). CFD simulations have been applied to evaluate the NSTF and NGNP RCCS designs. However, previous simulations found that convergence was very difficult to achieve in simulating the complex natural circulation. To resolve the convergence issue and increase the confidence of the CFD simulation results, additional CFD simulations were conducted using a more detailed mesh and a different solution scheme. It is found that, with the use of coupled flow and coupled energy models, the convergence can be greatly improved. Furthermore, the effects of convection in the cavity and the effects of the uncertainty in solid surface emissivity are also investigated. (authors)

  18. Tracking air-dropped drogues and dyes from aircraft in support of ERTS-1 circulation studies. [Delaware Bay

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Davis, G.; Wang, H.

    1974-01-01

    The author has identified the following significant results. For two years ERTS-1 has been employed to investigate current circulation patterns in Delaware Bay under different tidal, flow, and wind conditions. Since sufficient numbers of current meters and boats are not available, air-droppable drogues and dye packs have been developed and tested. The drogues consist of a styrofoam float and a line to which is attached a stainless steel biplane. The length of the line determines at what depth currents will be monitored. The floats are color coded to distinguish their movement and mark the depth of the biplanes. Simultaneously floating and anchored dye packs of fluorescein dye have been deployed from aircraft. The movement of the dye and drogues is tracked by sequential aerial photography, using fixed markers on shore or on buoys as reference points to calibrate the scale and direction of drogue movement. The current data obtained by this technique is then used to annotate current circulation maps derived from ERTS-1 imagery.

  19. Heat fluxes and roll circulations over the western Gulf Stream during an intense cold-air outbreak

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Ferguson, Michael P.

    1991-01-01

    Turbulence and heat fluxes in the marine atmospheric boundary layer (MABL) for three aircraft stacks near the western Gulf Stream front, observed during the Genesis of Atlantic Lows Experiment (GALE) January 28, 1986 cold-air outbreak, has been studied using mixed-layer scaling. The GOES image and stability parameter indicates that these three stacks were in the roll vortex regime. The turbulence structure in the MABL is studied for this case, as well as the significance of roll vortices to heat fluxes. The roll circulations are shown to contribute significantly to the sensible (temperature) and latent heat (moisture) fluxes with importance increasing upward. The results suggest that the entrainment at the MABL top might affect the the budgets of temperature and humidity fluxes in the lower MABL, but not in the unstable surface layer.

  20. The effect of clear-air turbulence on a model of the general circulation of the atmosphere

    NASA Technical Reports Server (NTRS)

    Heck, W. J.; Panofsky, H. A.; Bender, M. A.

    1977-01-01

    Mixing coefficients due to clear-air turbulence are estimated from turbulence observations from aircraft, and from large-scale dissipation estimates from the large-scale energy budgets. Maximum coefficients occur near middle-latitude jet streams, and eddy viscosity there is of order of 10 sq m/sec; eddy conductivity is estimated to be about ten times smaller. These coefficients are introduced into the 12-layer general circulation model of the National Center of Atmospheric Research. They produce an apparently significant, though small reduction in maximum speed of the jet, and a reduction in eddy energy. Further, the stratospheric polar-night jet is produced at about the correct location with about the correct intensity.

  1. Preparation, characterization, and photocatalytic studies on anatase nano-TiO{sub 2} at internal air lift circulating photocatalytic reactor

    SciTech Connect

    Xu, Hang Li, Mei; Jun, Zhang

    2013-09-01

    Graphical abstract: The micro morphological structure of the nano-TiO{sub 2} particles was also observed with TEM, as shown in figure. The TEM images clearly exhibited the homogeneous microstructure of particles with a size of around 10–15 nm. - Highlights: • Nano-TiO{sub 2} was prepared by complex techniques of sol–gel, micro-emulsion and solvent thermal. • The size of TiO{sub 2} was nano level and uniformity. • Nano-TiO{sub 2} exhibited high photo-catalytic activity at internal air lift circulating reactor. • The best nano-TiO{sub 2} dosage was obtained. - Abstract: Anatase nano-titania (TiO{sub 2}) powder was prepared by using a sol–gel process mediated in reverse microemulsion combined with a solvent thermal technique. The structures of the obtained TiO{sub 2} were characterized by TG-DSC, XRD, TEM. The photocatalytic decomposition of methylene blue (MB) on nano-TiO{sub 2} was studied by using an internal air lift circulating photocatalytic reactor. The results show that the anatase structure appears in the calcination temperature range of 400–510 °C, while the transformation of anatase into rutile takes place above 510 °C. The homogeneous microstructure of nano-TiO{sub 2} particles was obtained with a size of around 10–15 nm. In the photocatalytic performance, degradation process follows pseudo first order kinetics with different dosages of photocatalyst and initial MB concentrations and optimal TiO{sub 2} dosage is 0.1 g/L with neutral medium.

  2. A Comparison of the Red Green Blue Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Folmer, Michael; Dunion, Jason

    2014-01-01

    The Red Green Blue (RGB) Air Mass imagery is derived from multiple channels or paired channel differences. Multiple channel products typically provide additional information than a single channel can provide alone. The RGB Air Mass imagery simplifies the interpretation of temperature and moisture characteristics of air masses surrounding synoptic and mesoscale features. Despite the ease of interpretation of multiple channel products, the combination of channels and channel differences means the resulting product does not represent a quantity or physical parameter such as brightness temperature in conventional single channel satellite imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles of temperature, moisture, and ozone can provide insight about the air mass represented on the RGB Air Mass product and provide confidence in the product and representation of air masses despite the lack of a quantity to reference for interpretation. This study focuses on RGB Air Mass analysis of Hurricane Sandy as it moved north along the U.S. East Coast, while transitioning to a hybrid extratropical storm. Soundings and total column ozone retrievals were analyzed using data from the Cross-track Infrared and Advanced Technology Microwave Sounder Suite (CrIMSS) on the Suomi National Polar Orbiting Partnership satellite and the Atmospheric Infrared Sounder (AIRS) on the National Aeronautics and Space Administration Aqua satellite along with dropsondes that were collected from National Oceanic and Atmospheric Administration and Air Force research aircraft. By comparing these datasets to the RGB Air Mass, it is possible to capture quantitative information that could help in analyzing the synoptic environment enough to diagnose the onset of extratropical transition. This was done by identifying any stratospheric air intrusions (SAIs) that existed in the vicinity of Sandy as the wind

  3. The air-sea transformation and diapycnal overturning circulation within the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Isachsen, P. E.; Nøst, O. A.

    2012-04-01

    Air-sea flux climatologies and reanalyzes show that the bulk of the oceanic heat and buoyancy loss over the Nordic Seas takes place over interior regions not easily accessible by the time-mean large-scale currents. Eddy transport of heat and buoyancy, from the boundary currents and into the deep basins, is thought to be a key mechanism. Here we use gridded observations, theory and a modern parametrization of eddy transport to quantify the buoyancy budget of this region. The calculations confirm that mean currents are unable to explain the air-sea transformation that takes place over the interior basins of the Nordic Seas and that eddy transport instead dominates. The parametrization of eddy transport also suggests a significant overturning cell between the eastern and western parts of the Nordic Seas. This cell is, however, unaccounted for in the remaining data sets studied here.

  4. [Serological evidence of St. Louis encephalitis virus circulation in birds from Buenos Aires City, Argentina].

    PubMed

    Beltrán, Fernando J; Díaz, Luis A; Konigheim, Brenda; Molina, José; Beaudoin, Juan B; Contigiani, Marta; Spinsanti, Lorena I

    2015-01-01

    Our goal was to determine the presence of neutralizing antibodies against St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) in sera of wild and domestic birds from Buenos Aires City, Argentina. From October 2012 to April 2013, 180 samples were collected and processed by the microneutralization technique. A 7.2% of the sampled birds were seropositive for SLEV, while no seropositive birds for WNV were detected.

  5. Simultaneous quantification of 21 water soluble vitamin circulating forms in human plasma by liquid chromatography-mass spectrometry.

    PubMed

    Meisser Redeuil, Karine; Longet, Karin; Bénet, Sylvie; Munari, Caroline; Campos-Giménez, Esther

    2015-11-27

    This manuscript reports a validated analytical approach for the quantification of 21 water soluble vitamins and their main circulating forms in human plasma. Isotope dilution-based sample preparation consisted of protein precipitation using acidic methanol enriched with stable isotope labelled internal standards. Separation was achieved by reversed-phase liquid chromatography and detection performed by tandem mass spectrometry in positive electrospray ionization mode. Instrumental lower limits of detection and quantification reached <0.1-10nM and 0.2-25nM, respectively. Commercially available pooled human plasma was used to build matrix-matched calibration curves ranging 2-500, 5-1250, 20-5000 or 150-37500nM depending on the analyte. The overall performance of the method was considered adequate, with 2.8-20.9% and 5.2-20.0% intra and inter-day precision, respectively and averaged accuracy reaching 91-108%. Recovery experiments were also performed and reached in average 82%. This analytical approach was then applied for the quantification of circulating water soluble vitamins in human plasma single donor samples. The present report provides a sensitive and reliable approach for the quantification of water soluble vitamins and main circulating forms in human plasma. In the future, the application of this analytical approach will give more confidence to provide a comprehensive assessment of water soluble vitamins nutritional status and bioavailability studies in humans. PMID:26522745

  6. Interdecadal linkages between Pacific decadal oscillation and interhemispheric air mass oscillation and their possible connections with East Asian Monsoon

    NASA Astrophysics Data System (ADS)

    Lu, C.

    2015-12-01

    The Pacific decadal oscillation (PDO) recently emerged in the literature as a robust signal in the Northern Hemisphere climate variability. Many studies reported that the relationships between PDO and East Asian monsoon (EAM) and climate variability in China are significant. However, the possible mechanisms are still unclear. The present study investigates the interdecadal relationship between Pacific decadal oscillation (PDO) and interhemispheric air mass imbalance or oscillation (IHO) between the Northern and Southern Hemispheres. The possible connection of PDO and IHO with both East Asian monsoon and climate variability in China are also assessed in this study. It is found that the interdecadal components (11-38 years) of PDO, IHO, and EAM contribute large variance to low frequency variations, and they are well-matched with each other on (inter)decadal timescale. In particular, their negative phases mainly appeared in the 1970s and late 1990s, while positive phase in period from 1980s to mid 1990s. Decadal change of global mean air columnar temperature may be the key factor for the notable difference between PDO and IHO from mid 1970s to mid 1990s. The spatial distributions of PDO and IHO associated surface air temperature and surface pressure anomalies exhibit highly similar and large scale characteristics, indicative of their intimate linkage with air mass redistribution over global domain especially over 300S-500N. The PDO associated columnar integral of velocity potential anomalies that maintain the air mass redistribution, show a dipole pattern with air mass flux emanating mainly from the eastern hemisphere to the Pacific regions in positive PDO phase. This contributes to hemispherical and land-sea mass exchange and redistribution, and also leads to the decadal displacement of both upward and downward branch of Walker circulation. In positive phase of PDO, an anomalous anticyclone is found in the Mongolian region in both boreal summer and winter seasons

  7. Associations between circulating components of the renin-angiotensin-aldosterone system and left ventricular mass.

    PubMed Central

    Schunkert, H.; Hense, H. W.; Muscholl, M.; Luchner, A.; Kürzinger, S.; Danser, A. H.; Riegger, G. A.

    1997-01-01

    OBJECTIVE: Cardiac growth may be modulated in part by the trophic effects of neurohormones. The aim of the present study was to investigate the relation between the basal activity of the renin-angiotensin-aldosterone system and left ventricular mass. DESIGN: A population based sample of 615 middle-age subjects was studied by standardised echocardiography; anthropometric measurements; and biochemical quantification of renin, pro-renin, angiotensinogen, angiotensin converting enzyme (ACE), and aldosterone. RESULTS: Echocardiographic left ventricular mass index correlated significantly with arterial blood pressure, age, and body mass index. In addition, in men ACE activity was significantly related to left ventricular mass index in univariate (P = 0.0007) and multivariate analyses (P = 0.008). Men with left ventricular hypertrophy presented with significantly higher serum ACE concentrations than those with normal left ventricular mass index (P = 0.002). In both men and women serum aldosterone was strongly related to septal and posterior wall thickness. Furthermore, in women serum aldosterone was positively and independently associated with left ventricular mass index (P = 0.0001). This effect was most prominent in hypertensive women. Finally, women with left ventricular hypertrophy presented with significantly higher serum aldosterone (P = 0.01). No significant associations with left ventricular mass index were observed for angiotensinogen, renin, or pro-renin. CONCLUSIONS: The data suggest that the variability of serum ACE or aldosterone, as occurred in this large population based sample, may contribute to the modulation of left ventricular mass. Images PMID:9038690

  8. Influence of forced internal air circulation on airflow distribution and heat transfer in a gas double-dynamic solid-state fermentation bioreactor.

    PubMed

    Chen, Hongzhang; Qin, Lanzhi; Li, Hongqiang

    2014-02-01

    Internal air circulation affects the temperature field distribution in a gas double-dynamic solid-state fermentation bioreactor (GDSFB). To enhance heat transfer through strengthening internal air circulation in a GDSFB, we put an air distribution plate (ADP) into the bioreactor and studied the effects of forced internal air circulation on airflow, heat transfer, and cellulase activity of Trichoderma viride L3. Results showed that ADP could help form a steady and uniform airflow distribution, and with gas-guide tubes, air reversal was formed inside the bioreactor, thus resulting in a smaller temperature difference between medium and air by enhancing convective heat transfer inside the bioreactor. Using an ADP of 5.35 % aperture ratio caused a 1 °C decrease in the average temperature difference during the solid-state fermentation process of T. viride L3. Meanwhile, the cellulase activity of T. viride L3 increased by 13.5 %. The best heat-transfer effect was attained when using an ADP of 5.35 % aperture ratio and setting the fan power to 125 V (4.81 W) in the gas double-dynamic solid-state fermentation (GDSF) process. An option of suitable aperture ratio and fan power may be conducive to ADPs' industrial amplification.

  9. Influence of forced internal air circulation on airflow distribution and heat transfer in a gas double-dynamic solid-state fermentation bioreactor.

    PubMed

    Chen, Hongzhang; Qin, Lanzhi; Li, Hongqiang

    2014-02-01

    Internal air circulation affects the temperature field distribution in a gas double-dynamic solid-state fermentation bioreactor (GDSFB). To enhance heat transfer through strengthening internal air circulation in a GDSFB, we put an air distribution plate (ADP) into the bioreactor and studied the effects of forced internal air circulation on airflow, heat transfer, and cellulase activity of Trichoderma viride L3. Results showed that ADP could help form a steady and uniform airflow distribution, and with gas-guide tubes, air reversal was formed inside the bioreactor, thus resulting in a smaller temperature difference between medium and air by enhancing convective heat transfer inside the bioreactor. Using an ADP of 5.35 % aperture ratio caused a 1 °C decrease in the average temperature difference during the solid-state fermentation process of T. viride L3. Meanwhile, the cellulase activity of T. viride L3 increased by 13.5 %. The best heat-transfer effect was attained when using an ADP of 5.35 % aperture ratio and setting the fan power to 125 V (4.81 W) in the gas double-dynamic solid-state fermentation (GDSF) process. An option of suitable aperture ratio and fan power may be conducive to ADPs' industrial amplification. PMID:24347160

  10. Fluoride pollution of atmospheric precipitation and its relationship with air circulation and weather patterns (Wielkopolski National Park, Poland).

    PubMed

    Walna, Barbara; Kurzyca, Iwona; Bednorz, Ewa; Kolendowicz, Leszek

    2013-07-01

    A 2-year study (2010-2011) of fluorides in atmospheric precipitation in the open area and in throughfall in Wielkopolski National Park (west-central Poland) showed their high concentrations, reaching a maximum value of 2 mg/l under the tree crowns. These high values indicate substantial deposition of up to 52 mg/m(2)/year. In 2011, over 51% of open area precipitation was characterized by fluoride concentration higher than 0.10 mg/l, and in throughfall such concentrations were found in more than 86% of events. In 2010, a strong connection was evident between fluoride and acid-forming ions, and in 2011, a correlation between phosphate and nitrite ions was seen. Analysis of available data on F(-) concentrations in the air did not show an unequivocal effect on F(-) concentrations in precipitation. To find reasons for and source areas of high fluoride pollution, the cases of extreme fluoride concentration in rainwater were related to atmospheric circulation and weather patterns. Weather conditions on days of extreme pollution were determined by movement of weather fronts over western Poland, or by small cyclonic centers with meteorological fronts. Macroscale air advection over the sampling site originated in the western quadrant (NW, W, and SW), particularly in the middle layers of the troposphere (2,500-5,000 m a.s.l.). Such directions indicate western Poland and Germany as possible sources of the pollution. At the same time in the lower troposphere, air inflow was frequently from the north, showing short distance transport from local emitters, and from the agglomeration of Poznań. PMID:23114919

  11. The Analysis of PPM Levels of Gases in Air by Photoionization Mass Spectrometry

    ERIC Educational Resources Information Center

    Driscoll, John N.; Warneck, Peter

    1973-01-01

    Discusses analysis of trace gases in air by photoionization mass spectrometer. It is shown that the necessary sensitivity can be obtained by eliminating the UV monochromator and using direct ionization with a hydrogen light source. (JP)

  12. Topologically protected one-way edge mode in networks of acoustic resonators with circulating air flow

    NASA Astrophysics Data System (ADS)

    Ni, Xu; He, Cheng; Sun, Xiao-Chen; Liu, Xiao-ping; Lu, Ming-Hui; Feng, Liang; Chen, Yan-Feng

    2015-05-01

    Recent explorations of topology in physical systems have led to a new paradigm of condensed matters characterized by topologically protected states and phase transition, for example, topologically protected photonic crystals enabled by magneto-optical effects. However, in other wave systems such as acoustics, topological states cannot be simply reproduced due to the absence of similar magnetics-related sound-matter interactions in naturally available materials. Here, we propose an acoustic topological structure by creating an effective gauge magnetic field for sound using circularly flowing air in the designed acoustic ring resonators. The created gauge magnetic field breaks the time-reversal symmetry, and therefore topological properties can be designed to be nontrivial with non-zero Chern numbers and thus to enable a topological sonic crystal, in which the topologically protected acoustic edge-state transport is observed, featuring robust one-way propagation characteristics against a variety of topological defects and impurities. Our results open a new venue to non-magnetic topological structures and promise a unique approach to effective manipulation of acoustic interfacial transport at will.

  13. DNAPL REMOVAL MECHANISMS AND MASS TRANSFER CHARACTERISTICS DURING COSOLVENT-AIR FLOODING

    EPA Science Inventory

    The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass t...

  14. Experimental Determination of the Mass of Air Molecules from the Law of Atmospheres.

    ERIC Educational Resources Information Center

    Hayn, Carl H.; Galvin, Vincent, Jr.

    1979-01-01

    A gas pressure gauge has been constructed for use in a student experiment involving the law of atmospheres. From pressure data obtained at selected elevations the average mass of air molecules is determined and compared to that calculated from the molecular weights and percentages of constituents to the air. (Author/BB)

  15. Recent changes in air temperature, heat waves occurrences, and atmospheric circulation in Northern Africa

    NASA Astrophysics Data System (ADS)

    Fontaine, Bernard; Janicot, Serge; Monerie, Paul-Arthur

    2013-08-01

    study documents the time evolution of air temperature and heat waves occurrences over Northern Africa for the period 1979-2011. A significant warming (1°-3°C), appearing by the mid-1960s over Sahara and Sahel, is associated with higher/lesser frequency of warm/cold temperatures, as with longer duration and higher occurrences of heat waves. Heat waves episodes of at least 4 day duration have been examined after removing the long-term evolution. These episodes are associated with specific anomalies: (i) in spring, positive low-level temperature anomalies over the Sahel and Sahara; low and midlevel cyclonic rotation over Morocco associated with a Rossby wave pattern, lessening the Harmattan; more/less atmospheric moisture westward/eastward to 0°; upward/downward anomalies above the western/eastern regions associated with the Rossby wave pattern; (ii) in summer, a similar but weaker positive low-level temperature anomaly (up to 3°C); less moisture westward to 10°W, a cyclonic anomaly in central Sahel favoring the monsoon eastward to 0° and a midlevel anticyclonic anomaly over the Western Sahara, increasing southward the flux divergence associated with the African Easterly Jet. In March-May, two to three heat waves propagate eastward. They are preceded by an abnormal warm cell over Libya and southwesterlies over the West Sahara. A large trough stands over North Atlantic while midtropospheric subsidence and anticyclonic rotation reinforce over the continent, then migrates toward the Arabian peninsula in breaking up. These signals are spatially coherent and might suggest the role of short Rossby waves with an eastward group velocity and a baroclinic mode, possibly associated with jet stream deformation.

  16. Improving microbial air quality in air-conditioned mass transport buses by opening the bus exhaust ventilation fans.

    PubMed

    Luksamijarulkul, Pipat; Arunchai, Nongphon; Luksamijarulkul, Soavalug; Kaewboonchoo, Orawan

    2005-07-01

    The air quality in air-conditioned mass transport buses may affect bus drivers' health. In-bus air quality improvement with the voluntary participation of bus drivers by opening the exhaust ventilation fans in the bus was implemented in the Seventh Bus Zone of Bangkok Mass Transit Authority. Four bus numbers, including bus numbers 16, 63, 67 and 166, were randomly selected to investigate microbial air quality and to observe the effect of opening the exhaust ventilation fans in the bus. With each bus number, 9 to 10 air-conditioned buses (total, 39 air-conditioned buses) were included. In-bus air samples were collected at 5 points in each studied bus using the Millipore Air Tester. A total of 195 air samples were cultured for bacterial and fungal counts. The results reveal that the exhaust ventilation fans of 17 air-conditioned buses (43.6%) were opened to ventilate in-bus air during the cycle of the bus route. The means +/- SD of bacterial counts and fungal counts in the studied buses with opened exhaust ventilation fans (83.8 +/- 70.7 and 38.0 +/- 42.8 cfu/m3) were significantly lower than those in the studied buses without opened exhaust ventilation fans (199.6 +/- 138.8 and 294.1 +/- 178.7 cfu/m3), p < 0.0005. All the air samples collected from the studied buses with opened exhaust ventilation fans were at acceptable levels (< 500 cfu/m3) compared with 4.6% of the air samples collected from the studied buses without opened exhaust ventilation fans, which had high levels (> 500 cfu/m3). Of the studied buses with opened exhaust ventilation fans (17 buses), the bacterial and fungal counts after opening the exhaust ventilation fans (68.3 +/- 33.8 and 28.3 +/- 19.3 cfu/m3) were significantly lower than those before opening the exhaust ventilation fans (158.3 +/- 116.9 and 85.3 +/- 71.2 cfu/m3), p < 0.005.

  17. Aerosol composition and properties variation at the ground and over the column under different air masses advection in South Italy.

    PubMed

    Pavese, G; Lettino, A; Calvello, M; Esposito, F; Fiore, S

    2016-04-01

    Aerosol composition and properties variation under the advection of different air masses were investigated, as case studies, by contemporary measurements over the atmospheric column and at the ground in a semi-rural site in South Italy. The absence of local strong sources in this area allowed to characterize background aerosol and to compare particle mixing effects under various atmospheric circulation conditions. Aerosol optical depth (AOD) and Ǻngström parameters from radiometric measurements allowed the detection and identification of polluted, dust, and volcanic atmospheric conditions. AODs were the input for a suitable model to evaluate the columnar aerosol composition, according to six main atmospheric components (water-soluble, soot, sea salt accumulation, sea salt coarse, mineral dus,t and biological). Scanning electron microscope (SEM) analysis of particulate sampled with a 13-stage impactor at the ground showed not only fingerprints typical of the different air masses but also the effects of transport and aging on atmospheric particles, suggesting processes that changed their chemical and optical properties. Background columnar aerosol was characterized by 72% of water-soluble and soot, in agreement with ground-based findings that highlighted 60% of contribution from anthropogenic carbonate particles and soot. In general, a good agreement between ground-based and columnar results was observed. Under the advection of trans-boundary air masses, water-soluble and soot were always present in columnar aerosol, whereas, in variable percentages, sea salt and mineral particles characterized both dust and volcanic conditions. At the ground, sulfates characterized the amorphous matrix produced in finer stages by the evaporation of solutions of organic and inorganic aerosols. Sulfates were also one of the key players involved in heterogeneous chemical reactions, producing complex secondary aerosol, as such clay-sulfate internally mixed particle externally mixed

  18. Numerical Study on the Impact of SST Initialization on Regional Circulation and Air Pollution at Southern Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Jeon, W.; Lee, H.; Lee, S.

    2010-12-01

    Numerical simulations were carried out to investigate the impact of temporal resolution of sea surface temperature on regional circulation and air pollution over southern Korean Peninsula. Well urbanized target area with densely populated inventories called Gwangyang bay is situated at the southern part of the Korean Peninsula, and assessment period is from 15 to 19 August 2007 for investigating the SST impact under various synoptic conditions. A three-dimensional non-hydrostatic atmospheric model RAMS and New Generation Sea Surface Temperature (NGSST) data was applied in this study. Two different numerical experiments were carried out in accordance with the temporal resolution of SST, which are, NGSST without temporal update (case NO-UP), and temporally varied NGSST for whole period (case YES-UP). Based on the Buoy observation, SST at Geoje Island near Gwayang bay region increased 4.1°C for target period. This rapid variation of SST cannot be negligible to estimate the meteorological wind field and the distribution of photochemical ozone emitted at the well urbanized Gwangyang bay. Wind intensity including wind direction is also influenced by the temporal variation of SST distribution. In case YES-UP with high temporal resolution of SST, Sea breeze is stronger and more reasonable than that estimated in any other cases due to the precise information of SST distribution. In IOA analysis, most successfully estimated IOA values for surface air temperature and wind speed arose in case YES-UP and their values reached on the 0.958 and 0.829, respectively. These differences were due to the discrepancy of the temperature gradient caused by different SST initialization. Diurnal variation of temperature and wind speed for YES_UP has indicated great agreement with the observation data and the statistics such as root mean squared error, index of agreement were also better than NO_UP. In order to assess the influence of the difference of the meteorological input data to air

  19. The extent of seawater circulation in the aquifer and its role in elemental mass balances: A lesson from the Dead Sea

    NASA Astrophysics Data System (ADS)

    Kiro, Yael; Weinstein, Yishai; Starinsky, Abraham; Yechieli, Yoseph

    2014-05-01

    This paper shows for the first time a field-based estimation of the volume of dispersive density-driven long-term seawater circulation in coastal aquifers, which is crucial to the understanding of water-rock interaction and to the assessment of its potential impact on elemental mass balances in the sea. The Dead Sea is an ideal place for studying this type of circulation due to the absence of tides and the accessibility of the shallow fresh-saline transition zone. The unique antithetical behavior of 226Ra and 228Ra during seawater circulation in the Dead Sea aquifer, where 228Ra is added and 226Ra is removed, provides a robust new method for quantifying aquifer circulation. Here we estimate water circulation through the Dead Sea aquifer to be 400 million m3/yr (˜2.5 million m3/yr per 1 km of shoreline), which is ˜20% of the fresh water inflow prior to the 1960s. This large volume can affect trace element concentrations in the Dead Sea, e.g. it is a sink for 226Ra, Ba and U and a source for 228Ra and Fe. These results suggest that dispersive density-driven seawater circulation in aquifers may play an important role in mass balances in other lacustrine and oceanic settings.

  20. Aerial observations of air masses transported from East Asia to the Western Pacific: Vertical structure of polluted air masses

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Shiro; Ikeda, Keisuke; Hanaoka, Sayuri; Watanabe, Izumi; Arakaki, Takemitsu; Bandow, Hiroshi; Sadanaga, Yasuhiro; Kato, Shungo; Kajii, Yoshizumi; Zhang, Daizhou; Okuyama, Kikuo; Ogi, Takashi; Fujimoto, Toshiyuki; Seto, Takafumi; Shimizu, Atsushi; Sugimoto, Nobuo; Takami, Akinori

    2014-11-01

    There has been only limited information about the vertical chemical structure of the atmosphere, so far. We conducted aerial observations on 11, 12, and 14 December 2010 over the northern part of the East China Sea to analyze the spatial distribution of atmospheric pollutants from East Asia and to elucidate transformation processes of air pollutants during the long-range transport. On 11 December, a day on which Asian dust created hazy conditions, the average PM10 concentration was 40.69 μg m-3, and we observed high concentrations of chemical components such as Ca2+, NO3-, SO42-, Al, Ca, Fe, and Zn. The height of the boundary layer was about 1200 m, and most species of pollutants (except for dust particles and SO2) had accumulated within the boundary layer. In contrast, concentrations of pollutants were low in the boundary layer (up to 1000 m) on 12 December because clean Pacific air from the southeast had diluted the haze. However, we observed natural chemical components (Na+, Cl-, Al, Ca, and Fe) at 3000 m, the indication being that dust particles, including halite, were present in the lower free troposphere. On 14 December, peak concentrations of SO2 and black carbon were measured within the boundary layer (up to 700 m) and at 2300 m. The concentrations of anthropogenic chemical components such as NO3-, NH4+, and Zn were highest at 500 m, and concentrations of both anthropogenic and natural chemical components (SO42-, Pb, Ca2+, Ca, Al, and Fe) were highest at 2000 m. Thus, it was clearly indicated that the air above the East China Sea had a well-defined, layered structure below 3000 m.

  1. [Genomic heterogeneity of hepatitis B virus, genotype A circulating in the metropolitan area of Buenos Aires, Argentina].

    PubMed

    Fernandez, C; Mariana; de Torres, R A

    1996-01-01

    HVB DNA was extracted from highly purified Dane particles, from sera of HBV viremic patients, collected in the metropolitan area of Buenos Aires (Argentina). HBV DNA was cloned in pUC18 vector, amplified in Escherichia coli DH5 F'. Plasmids were recovered and analyzed for HBV DNA inserts. Three recombinant plasmids, pHB4, pHB7 and pHB20 were selected, and HBVDNA inserts sequenced. The resulted sequences were incorporated at the GenBank, with the following accession numbers: PHB4P3=U33188; PHB4P5=U33189; PHB7P3=U33190; PHB7P5=U33191 and PHB20=U33190; PHB7P5=U33191 and PHB20=U33187. All belongs to the genotype A, pHB4 and pHB20 have a very close relation in between each other and with L13994 sequence, from North America origin. pHB7 have a significant distance from pHB4 and pHB20 and have a discrete homology with m57633 detected in Philippines. pHB4 shows a mutation at the T 3182-Leu in the preS1 region that change Pro for Leu, this mutation is absent in 125 sequences selected (having a 65% or more of homology) from NCBI by Blast algortm. The sequence of the pre C regions of all three inserts do not show any evidence to belong to the e-or scape mutants. Type A genotypes shows to be common in the area, but a hight degree of divergence have been demonstrate between two circulating strains. PMID:9335928

  2. [Genomic heterogeneity of hepatitis B virus, genotype A circulating in the metropolitan area of Buenos Aires, Argentina].

    PubMed

    Fernandez, C; Mariana; de Torres, R A

    1996-01-01

    HVB DNA was extracted from highly purified Dane particles, from sera of HBV viremic patients, collected in the metropolitan area of Buenos Aires (Argentina). HBV DNA was cloned in pUC18 vector, amplified in Escherichia coli DH5 F'. Plasmids were recovered and analyzed for HBV DNA inserts. Three recombinant plasmids, pHB4, pHB7 and pHB20 were selected, and HBVDNA inserts sequenced. The resulted sequences were incorporated at the GenBank, with the following accession numbers: PHB4P3=U33188; PHB4P5=U33189; PHB7P3=U33190; PHB7P5=U33191 and PHB20=U33190; PHB7P5=U33191 and PHB20=U33187. All belongs to the genotype A, pHB4 and pHB20 have a very close relation in between each other and with L13994 sequence, from North America origin. pHB7 have a significant distance from pHB4 and pHB20 and have a discrete homology with m57633 detected in Philippines. pHB4 shows a mutation at the T 3182-Leu in the preS1 region that change Pro for Leu, this mutation is absent in 125 sequences selected (having a 65% or more of homology) from NCBI by Blast algortm. The sequence of the pre C regions of all three inserts do not show any evidence to belong to the e-or scape mutants. Type A genotypes shows to be common in the area, but a hight degree of divergence have been demonstrate between two circulating strains.

  3. Assessment of the impact of the meteorological meso-scale circulation on air quality in arid subtropical region.

    PubMed

    Charabi, Yassine; Al-Bulooshi, Ali; Al-Yahyai, Sultan

    2013-03-01

    In this paper, COSMO numerical weather prediction model is used to simulate land-sea breeze circulation in the north coast of Oman and to analyze the variability of the PBL depth. Typical summer day 1st August 2009 and winter day 1st January 2009 were simulated and verified by surface observations. The COSMO model was initialized using the German global model which runs as 40 km resolution and 40 vertical layers. The simulations show differences in the onset, strength, and inland penetration of the sea breeze. The high sea-land thermal contrast in the summer season induces earlier onset and progression of the sea breeze with larger horizontal and vertical extents. The summer and winter inland penetration is simulated around 150 and 65 km, respectively. The PBL depth was defined from the verticals profiles of the turbulence kinetic energy (TKE). The simulated PBL height varied at 1,600 m in summer and 700 m in the winter case. These results are in general in good agreement with the simulations of the National Centers for Environmental Prediction Global Data Assimilation System (NCEP-GDAS) model. The dispersive ability of the atmosphere was tested through the vertical mixing coefficient (VMC) generated by NCEP-GDAS simulations. The VMC during the summer simulated case is approximately four times larger than the respective one during the winter case. Consequently, during the advection of winter sea breeze, a shallow dome less than 100 m is shaped and forms an obstacle to the air-pollutant dispersion.

  4. Influence of the relative optical air mass on ultraviolet erythemal irradiance

    NASA Astrophysics Data System (ADS)

    Antón, M.; Serrano, A.; Cancillo, M. L.; García, J. A.

    2009-12-01

    The main objective of this article is to analyze the relationship between the transmissivity for ultraviolet erythemal irradiance (UVER) and the relative optical air mass at Badajoz (Southwestern Spain). Thus, a power expression between both variables is developed, which analyses in detail how atmospheric transmission is influenced by the total ozone column (TOC) and the atmospheric clearness. The period of analysis extends from 2001 to 2005. The experimental results indicate that clearness conditions play an important role in the relationship between UVER transmissivity and the relative optical air mass, while the effect of TOC is much smaller for this data set. In addition, the results show that UVER transmissivity is more sensitive to changes in atmospheric clearness than to TOC variability. Changes in TOC values higher than 15% cause UVER trasnmissivity to vary between 14% and 22%, while changes between cloud-free and overcast conditions produce variations in UVER transmissivity between 68% and 74% depending on the relative optical air mass.

  5. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  6. Interaction of mid-latitude air masses with the polar dome area during RACEPAC and NETCARE

    NASA Astrophysics Data System (ADS)

    Bozem, Heiko; Hoor, Peter; Koellner, Franziska; Kunkel, Daniel; Schneider, Johannes; Schulz, Christiane; Herber, Andreas; Borrmann, Stephan; Wendisch, Manfred; Ehrlich, Andre; Leaitch, Richard; Willis, Megan; Burkart, Julia; Thomas, Jennie; Abbatt, Jon

    2016-04-01

    We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories as well as Flexpart particle dispersion modeling we analyze the transport regimes of mid-latitude air masses traveling to the high Arctic prevalent during spring (RACEPAC 2014, NETCARE 2015) and summer (NETCARE 2014). In general more northern parts of the high Arctic (Lat > 75°N) were relatively unaffected from mid-latitude air masses. In contrast, regions further south are influenced by air masses from Asia and Russia (eastern part of Canadian Arctic and European Arctic) as well as from North America (central and western parts of Canadian Arctic). The transition between the mostly isolated high Arctic and more southern regions indicated by tracer gradients is remarkably sharp. This allows for a chemical definition of the Polar dome based on the variability of CO and CO2 as a marker. Isentropic surfaces that slope from the surface to higher altitudes in the high Arctic form the polar dome that represents a transport barrier for mid-latitude air masses to enter the lower troposphere in the high Arctic. Synoptic-scale weather systems frequently disturb this transport barrier and foster the exchange between air masses from the mid-latitudes and polar regions. This can finally lead to enhanced pollution levels in the lower polar troposphere. Mid-latitude pollution plumes from biomass burning or flaring entering the polar dome area lead to an enhancement of 30% of the observed CO mixing ratio within the polar dome area.

  7. The circulation and water masses of the Antarctic shelf and continental slope between 30 and 80∘E

    NASA Astrophysics Data System (ADS)

    Meijers, A. J. S.; Klocker, A.; Bindoff, N. L.; Williams, G. D.; Marsland, S. J.

    2010-05-01

    The circulation and water masses from the Antarctic continental shelf to 62∘S between 30 and 80∘E are described using hydrographic data collected on seven hydrographic sections during the Baseline Research on Oceanography, Krill and the Environment-West (BROKE-West) experiment. The eastern limb of the Weddell Gyre dominates circulation between 30 and 40∘E, and is significantly cooler and fresher than the region to the east. The Antarctic Circumpolar Current (ACC) extends from the north into the survey region east of 40∘E, reaching as far south as 65.5∘S at 60∘E. This results in increasing observed maximum temperature and salinities progressively towards the east, peaking at 80∘E due to the intrusion of the southern ACC Front (sACCF) to 63∘S. This southward extension is steered by the southern end of Kerguelen Plateau, causing a horizontal shear of over 0.15ms-1 between the eastward ACC and westward-flowing Antarctic Slope Current (ASC). The ASC is observed at all six meridional sections immediately north of the shelf break. It is strongly barotropic and transports a total of 15.8±7.4Sv westwards, while the bottom referenced baroclinic component only contributes 1.3±0.3Sv. At each section this current intensifies to a narrow westward 'jet' with absolute velocities up to 0.3ms-1 over the steepest shelf slope gradients. At 70∘E a 'V' shape is observed in the ASF. This, and the nearby presence of denser shelf water and ice-shelf water, is characteristic of Antarctic Bottom Water (AABW) formation, but no new AABW is found on this section. Instead, significantly warmer, saltier and less oxygenated AABW to the east and newly formed AABW high on the continental slope immediately to the west suggest a formation region just west of 70∘E. This newly formed AABW progressively becomes warmer and saltier west of 60∘E and is observed extending offshore and moving westward below eastward flowing water masses. ACC frontal positions are found to be 1-2

  8. Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement

    SciTech Connect

    Desantes, J.M.; Galindo, J.; Guardiola, C.; Dolz, V.

    2010-01-15

    Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementing standard methods. Present paper uses in cylinder pressure increase during the intake stroke for inferring the trapped air mass. The method is validated on two different turbocharged diesel engines and compared with the standard methods. (author)

  9. Apparatus and method for generating large mass flow of high temperature air at hypersonic speeds

    NASA Technical Reports Server (NTRS)

    Sabol, A. P.; Stewart, R. B. (Inventor)

    1973-01-01

    High temperature, high mass air flow and a high Reynolds number test air flow in the Mach number 8-10 regime of adequate test flow duration is attained by pressurizing a ceramic-lined storage tank with air to a pressure of about 100 to 200 atmospheres. The air is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the air over an electric arc heater means. The air cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized air in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized air effects an exothermic reaction which maintains the pressure and temperature of the pressurized air during the rapid release.

  10. The Use of Red Green Blue (RGB) Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Zavodsky, Bradley; Molthan, Andrew; Jedlovec, Gary

    2013-01-01

    AIRS ozone and model PV analysis confirm the stratospheric air in RGB Air Mass imagery. Trajectories confirm winds south of the low were distinct from CCB driven winds. Cross sections connect the tropopause fold, downward motion, and high nearsurface winds. Comparison to conceptual models show Shapiro-Keyser features and sting jet characteristics were observed in a storm that impacted the U.S. East Coast. RGB Air Mass imagery can be used to identify stratospheric air and regions susceptible to tropopause folding and attendant non-convective winds.

  11. A Lower Olfactory Capacity Is Related to Higher Circulating Concentrations of Endocannabinoid 2-Arachidonoylglycerol and Higher Body Mass Index in Women.

    PubMed

    Pastor, Antoni; Fernández-Aranda, Fernando; Fitó, Montserrat; Jiménez-Murcia, Susana; Botella, Cristina; Fernández-Real, Jose M; Frühbeck, Gema; Tinahones, Francisco J; Fagundo, Ana B; Rodriguez, Joan; Agüera, Zaida; Langohr, Klaus; Casanueva, Felipe F; de la Torre, Rafael

    2016-01-01

    The endocannabinoid (eCB) system can promote food intake by increasing odor detection in mice. The eCB system is over-active in human obesity. Our aim is to measure circulating eCB concentrations and olfactory capacity in a human sample that includes people with obesity and explore the possible interaction between olfaction, obesity and the eCB system. The study sample was made up of 161 females with five groups of body mass index sub-categories ranging from under-weight to morbidly obese. We assessed olfactory capacity with the "Sniffin´Sticks" test, which measures olfactory threshold-discrimination-identification (TDI) capacity. We measured plasma concentrations of the eCBs 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine or anandamide (AEA), and several eCB-related compounds, 2-acylglycerols and N-acylethanolamines. 2-AG and other 2-acylglycerols fasting plasma circulating plasma concentrations were higher in obese and morbidly obese subjects. AEA and other N-acylethanolamine circulating concentrations were lower in under-weight subjects. Olfactory TDI scores were lower in obese and morbidly obese subjects. Lower TDI scores were independently associated with higher 2-AG fasting plasma circulating concentrations, higher %body fat, and higher body mass index, after controlling for age, smoking, menstruation, and use of contraceptives. Our results show that obese subjects have a lower olfactory capacity than non-obese ones and that elevated fasting plasma circulating 2-AG concentrations in obesity are linked to a lower olfactory capacity. In agreement with previous studies we show that eCBs AEA and 2-AG, and their respective congeners have a distinct profile in relation to body mass index. The present report is the first study in humans in which olfactory capacity and circulating eCB concentrations have been measured in the same subjects. PMID:26849214

  12. A Lower Olfactory Capacity Is Related to Higher Circulating Concentrations of Endocannabinoid 2-Arachidonoylglycerol and Higher Body Mass Index in Women

    PubMed Central

    Pastor, Antoni; Fernández-Aranda, Fernando; Fitó, Montserrat; Jiménez-Murcia, Susana; Botella, Cristina; Fernández-Real, Jose M.; Frühbeck, Gema; Tinahones, Francisco J.; Fagundo, Ana B.; Rodriguez, Joan; Agüera, Zaida; Langohr, Klaus; Casanueva, Felipe F.; de la Torre, Rafael

    2016-01-01

    The endocannabinoid (eCB) system can promote food intake by increasing odor detection in mice. The eCB system is over-active in human obesity. Our aim is to measure circulating eCB concentrations and olfactory capacity in a human sample that includes people with obesity and explore the possible interaction between olfaction, obesity and the eCB system. The study sample was made up of 161 females with five groups of body mass index sub-categories ranging from under-weight to morbidly obese. We assessed olfactory capacity with the “Sniffin´Sticks” test, which measures olfactory threshold-discrimination-identification (TDI) capacity. We measured plasma concentrations of the eCBs 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine or anandamide (AEA), and several eCB-related compounds, 2-acylglycerols and N-acylethanolamines. 2-AG and other 2-acylglycerols fasting plasma circulating plasma concentrations were higher in obese and morbidly obese subjects. AEA and other N-acylethanolamine circulating concentrations were lower in under-weight subjects. Olfactory TDI scores were lower in obese and morbidly obese subjects. Lower TDI scores were independently associated with higher 2-AG fasting plasma circulating concentrations, higher %body fat, and higher body mass index, after controlling for age, smoking, menstruation, and use of contraceptives. Our results show that obese subjects have a lower olfactory capacity than non-obese ones and that elevated fasting plasma circulating 2-AG concentrations in obesity are linked to a lower olfactory capacity. In agreement with previous studies we show that eCBs AEA and 2-AG, and their respective congeners have a distinct profile in relation to body mass index. The present report is the first study in humans in which olfactory capacity and circulating eCB concentrations have been measured in the same subjects. PMID:26849214

  13. The Hydrothermal Circulation of the Atmosphere

    NASA Astrophysics Data System (ADS)

    Kjellsson, J.; Doos, K.; Laliberté, F. B.; Zika, J. D.

    2012-12-01

    The atmospheric circulation maintains the energy balance between the warm/moist regions and the colder/drier regions of the Earth. A well-studied aspect of the atmospheric circulation is the time-averaged zonal-mean meridional overturning circulation. The meridional overturning describes the Hadley, Ferrel and Polar Cells in each hemisphere. However, in isobaric coordinates, the zonal average is unable to capture zonally asymmetric features such as the Walker circulation and transient exchanges of heat and moisture. The Walker Circulation is restricted to equatorial regions, and is commonly studied using a meridional mean over a limited region with ill-defined latitudinal boundaries. The Walker Circulation is thus neither mass-conserving nor uniquely defined. To overtcome these limitations, the Walker circulation is often diagnosed using vertical velocity. As a consequence, it is difficult to distinguish between the zonal-mean circulation (Hadley Circulation) and the zonal asymmetries (Walker Circulation). Global mass and energy transport is here investigated using a moisture-heat perspective. A hydrothermal streamfunction is defined where latent heat and dry static energy act as coordinates. Because the hydrothermal streamfunction resides in purely thermodynamical space, it does not differentiate between zonal, meridional, or vertical transports. The hydrothermal streamfunction shows the global overturning circulation as a unified cycle. It describes a cycle with three branches: i) a convective branch where latent heat is converted into sensible heat along moist adiabats, ii) a cooling branch where dry air loses energy due to radiative damping and iii) a return branch where cold, dry air is heated and moistened following the Clausius-Clapeyron relationship. These three branches form a single cell of more than 400 Sv with at least 100 Sv due to zonal motions such as the Walker Circulation. The cell is also found fairly stationary on seasonal and inter

  14. Hurricane-related air-sea interactions, circulation modifications, and coastal impacts on the eastern Louisiana coastline

    NASA Astrophysics Data System (ADS)

    Walker, N. D.; Pilley, C.; Li, C.; Liu, B.; Leben, R. R.; Raghunthan, V.; Ko, D.; Teague, W. J.

    2012-12-01

    Beginning in 1995, Atlantic hurricane activity increased significantly relative to the 1970s and 1980s. In 2005, records were broken when two hurricanes intensified rapidly to Category 5 for a period of time within the Gulf of Mexico, later landed, and flooded vast expanses of Louisiana's coastal regions within the span of 30 days. In this study, we investigate major hurricane events (including 2005) to elucidate air-sea interactions pertinent to hurricane intensity changes, shelf circulation, coastal flooding, and coastal land losses. We employ satellite measurements from passive sensors (temperature, true color, pigments) and active sensors (scatterometers, altimeters) in tandem with in-situ measurements from WAVCIS, NDBC, USGS, and NRL, as well as dedicated field campaigns along the coast. A selection of hurricane events during the 1998 to 2008 time period are used in this investigation. Research has shown that the Loop Current and its warm-core anticyclonic eddies (with high heat content) can intensify hurricanes transiting the Gulf; whereas, the cold-core cyclonic eddies (which are upwelling regions) can weaken hurricanes. Hurricane winds can intensify cold-core cyclonic eddies, which in some cases can impact outer shelf currents, mixing, and thermal structure throughout the water column. The exceptionally strong winds and waves in the northeast quadrant of these cyclonic atmospheric storms drive strong and long-lived westward currents. Storm surges and/or set-up of 2-6 m commonly occur along the Louisiana coastline, sometimes as a result of hurricanes traveling across the central Gulf of Mexico, at great distances from the coastal region experiencing the flooding (e.g. Hurricanes Rita and Gustav). The eastern shelf, north of the Mississippi River Birdfoot Delta, is particularly vulnerable to water level set-up and storm surge intensification due to the coastal orientation that causes the trapping of water. This area experienced land loss of 169 km2, or ~20

  15. Interactions between mass balance, atmospheric circulation, and recent climate change on the Djankuat Glacier, Caucasus Mountains, Russia

    NASA Astrophysics Data System (ADS)

    Shahgedanova, Maria; Stokes, Chris R.; Gurney, Stephen D.; Popovnin, Viktor

    2005-02-01

    This paper reports recent changes in the mass balance record from the Djankuat Glacier, central greater Caucasus, Russia, and investigates possible relationships between the components of mass balance, local climate, and distant atmospheric forcing. The results clearly show that a strong warming signal has emerged in the central greater Caucasus, particularly since the 1993/1994 mass balance year, and this has led to a significant increase in the summer ablation of Djankuat. At the same time, there has been no compensating consistent increase in winter precipitation and accumulation leading to the strong net loss of mass and increase in glacier runoff. Interannual variability in ablation and accumulation is partly associated with certain major patterns of Northern Hemisphere climatic variability. The positive phase of the North Pacific (NP) teleconnection pattern forces negative geopotential height and temperature anomalies over the Caucasus in summer and results in reduced summer melt, such as in the early 1990s, when positive NP extremes resulted in a temporary decline in ablation rates. The positive phase of the NP is related to El Niño-Southern Oscillation, and it is possible that a teleconnection between the tropical Pacific sea surface temperatures and summer air temperatures in the Caucasus is bridged through the NP pattern. More recently, the NP pattern was predominantly negative, and this distant moderating forcing on summer ablation in the Caucasus was absent. Statistically significant correlations are observed between accumulation and the Scandinavian (SCA) teleconnection pattern. The frequent occurrence of the positive SCA phase at the beginning of accumulation season results in lower than average snowfall and reduced accumulation. The relationship between the North Atlantic Oscillation (NAO), Arctic Oscillation, and accumulation is weak, although positive precipitation anomalies in the winter months are associated with the negative phase of the NAO. A

  16. Thermocline circulation and ventilation of the East/Japan Sea, part I: Water-mass characteristics and transports

    NASA Astrophysics Data System (ADS)

    You, Yuzhu; Chang, Kyung-Il; Yun, Jae-Yul; Kim, Kyung-Ryul

    2010-07-01

    three other major convection sites of the world's oceans, the Gulf of Lions, Labrador Sea and Greenland Sea, showing some common and distinctive features, especially the extremely low salinity of the EJS. Water-mass properties on neutral density surfaces are analyzed with the water-mass Turner angle (WTu) and circulation and transport are deducted from geostrophic calculations. From the 15-year mean hydrography, a basin-wide net annual mean transport of about 2.10±0.29 Sv (1 Sv=10 6 m 3 s -1) is estimated with summer and winter transports of 2.56±0.36 and 1.63±0.23 Sv, respectively. This transport is slightly less than the annual mean transport of the Tsushima Current at the KTS, 2.4 Sv from cable and 2.3 Sv from other direct current meter and geostrophic methods but matches the ±14% error bar of ±0.29 Sv adjusted by ±150 dbar from the reference level of 800 dbar. This error bar is close to the error of ±0.34 Sv determined from water-mass conservation residual in a separated study. Three mechanisms are discovered to explain the seasonal difference in the Tsushima Current transports: the stronger winter Ekman pumping, outcropping and southward crossing flow. During winter, the Tsushima Current branches are imposed under strong wind stress curl in the Ulleung Basin and Yamato Basin, showing a doubling Ekman downwelling transport, partly weakening the Tsushima Current flow in the eastern boundary. Meanwhile the thermocline isopycnal surfaces outcrop in winter, reducing volume transport due to reduced space and thickness. The southward currents in the southern Ulleung Basin and Yamato Basin are perpendicular to the Tsushima Current branches west of Japan, which weakens the eastern boundary current in winter.

  17. Inert gas purgebox for Fourier transform ion cyclotron resonance mass spectrometry of air-sensitive solids

    NASA Astrophysics Data System (ADS)

    May, Michael A.; Marshall, Alan G.

    1994-03-01

    A sealed rigid ``purgebox'' makes it possible to load air- and/or moisture-sensitive solids into the solids probe inlet of a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer. A pelletized sample is transferred (in a sealed canister) from a commercial drybox to a Lucite(R) purgebox. After the box is purged with inert gas, an attached glove manipulator is used to transfer the sample from the canister to the solids probe of the mass spectrometer. Once sealed inside the inlet, the sample is pre-evacuated and then passed into the high vacuum region of the instrument at ˜10-7 Torr. The purgebox is transparent, portable, and readily assembled/disassembled. Laser desorption FT/ICR mass spectra of the air- and moisture-sensitive solids, NbCl5. NbCl2(C5H5)2, and Zr(CH3)2(C5H5)2 are obtained without significant oxidation. The residual water vapor concentration inside the purgebox was measured as 100±20 ppm after a 90-min purge with dry nitrogen gas. High-resolution laser desorption/ionization mass spectrometry of air-sensitive solids becomes feasible with the present purgebox interface. With minor modification of the purgebox geometry, the present method could be adapted to any mass spectrometer equipped with a solid sample inlet.

  18. Airborne mass spectrometers: four decades of atmospheric and space research at the Air Force research laboratory.

    PubMed

    Viggiano, A A; Hunton, D E

    1999-11-01

    Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general. PMID:10548806

  19. Airborne mass spectrometers: four decades of atmospheric and space research at the Air Force research laboratory.

    PubMed

    Viggiano, A A; Hunton, D E

    1999-11-01

    Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general.

  20. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  1. Measuring Air-water Interfacial Area for Soils Using the Mass Balance Surfactant-tracer Method

    PubMed Central

    Araujo, Juliana B.; Mainhagu, Jon; Brusseau, Mark L.

    2015-01-01

    There are several methods for conducting interfacial partitioning tracer tests to measure air-water interfacial area in porous media. One such approach is the mass balance surfactant tracer method. An advantage of the mass-balance method compared to other tracer-based methods is that a single test can produce multiple interfacial area measurements over a wide range of water saturations. The mass-balance method has been used to date only for glass beads or treated quartz sand. The purpose of this research is to investigate the effectiveness and implementability of the mass-balance method for application to more complex porous media. The results indicate that interfacial areas measured with the mass-balance method are consistent with values obtained with the miscible-displacement method. This includes results for a soil, for which solid-phase adsorption was a significant component of total tracer retention. PMID:25950136

  2. Turbulent heat and mass transfers across a thermally stratified air-water interface

    NASA Technical Reports Server (NTRS)

    Papadimitrakis, Y. A.; Hsu, Y.-H. L.; Wu, J.

    1986-01-01

    Rates of heat and mass transfer across an air-water interface were measured in a wind-wave research facility, under various wind and thermal stability conditions (unless otherwise noted, mass refers to water vapor). Heat fluxes were obtained from both the eddy correlation and the profile method, under unstable, neutral, and stable conditions. Mass fluxes were obtained only under unstable stratification from the profile and global method. Under unstable conditions the turbulent Prandtl and Schmidt numbers remain fairly constant and equal to 0.74, whereas the rate of mass transfer varies linearly with bulk Richardson number. Under stable conditions the turbulent Prandtl number rises steadily to a value of 1.4 for a bulk Richardson number of about 0.016. Results of heat and mass transfer, expressed in the form of bulk aerodynamic coefficients with friction velocity as a parameter, are also compared with field data.

  3. Measuring air-water interfacial area for soils using the mass balance surfactant-tracer method.

    PubMed

    Araujo, Juliana B; Mainhagu, Jon; Brusseau, Mark L

    2015-09-01

    There are several methods for conducting interfacial partitioning tracer tests to measure air-water interfacial area in porous media. One such approach is the mass balance surfactant tracer method. An advantage of the mass-balance method compared to other tracer-based methods is that a single test can produce multiple interfacial area measurements over a wide range of water saturations. The mass-balance method has been used to date only for glass beads or treated quartz sand. The purpose of this research is to investigate the effectiveness and implementability of the mass-balance method for application to more complex porous media. The results indicate that interfacial areas measured with the mass-balance method are consistent with values obtained with the miscible-displacement method. This includes results for a soil, for which solid-phase adsorption was a significant component of total tracer retention.

  4. Impact of vertical structure on water mass circulation in a tropical lagoon (Ebrié, Ivory Coast)

    NASA Astrophysics Data System (ADS)

    Brenon, Isabelle; Audouin, Olivier; Pouvreau, Nicolas; Maurin, Jean-Christophe

    2009-09-01

    A one-dimensional vertical model has been developed to simulate the water mass circulation along the vertical structure in all deep coastal areas. The model has hydrodynamic and transport components solved using finite difference scheme. The one-dimensional vertical model results are coupled to the vertically averaged two-dimensional model results at each point of a horizontal grid. A theoretical salinity profile is introduced for each vertically integrated value obtained from the 2DH model results. A viscosity profile, simulating a viscosity value close to zero at the surface and with large viscosity gradients, is applied along the water column. The model is applied to the Vridi channel, connecting the Ebrié lagoon to the sea (Ivory Coast). The response of the Ebrié lagoon is studied in terms of inflow and outflow of water in the system through the Vridi channel. Due to the abrupt variation of the surface slope, vertical velocities along the water column show an anticlockwise spiral from bottom to surface during a tidal cycle. Due to the bottom friction and to the vertical viscosity profile, velocities decrease from surface to bottom. However, the freshwater inflow slows down the tidal propagation during the flood and causes the surface velocity to be smaller than the bottom velocity at mid-tide. Close to the bottom, velocities follow an anticlockwise movement due to the tidal propagation. At the water surface, velocities follow only an alternative movement of either ebb or flood, along the channel direction. No cross shore velocities can develop at the surface in the channel.

  5. MISR Aerosol Air Mass Type Mapping over Mega-City: Validation and Applications

    NASA Astrophysics Data System (ADS)

    Patadia, F.; Kahn, R. A.

    2010-12-01

    Most aerosol air-quality monitoring in mega-city environments is done from scattered ground stations having detailed chemical and optical sampling capabilities. Satellite instruments such as the Multi-angle Imaging SpectroRadiometer (MISR) can retrieve total-column Aerosol Optical Depth (AOD), along with some information about particle microphysical properties. Although the particle property information from MISR is much less detailed than that obtained from the ground sampling stations, the coverage is extensive, making it possible to put individual surface observations into the context of regional aerosol air mass types. This paper presents an analysis of MISR aerosol observations made coincident with aircraft and ground-based instruments during the INTEX-B field campaign. These detailed comparisons of satellite aerosol property retrievals against dedicated field measurements provide the opportunity to validate the retrievals quantitatively at a regional level, and help to improve aerosol representation in retrieval algorithms. Validation of MISR retrieved AOD and other aerosol properties over the INTEX-B study region in and around Mexico City will be presented. MISR’s ability to distinguish among aerosol air mass types will be discussed. The goal of this effort is to use the MISR aerosol property retrievals for mapping both aerosol air mass type and AOD gradients in mega-city environments over the decade-plus that MISR has made global observations.

  6. Establishing Lagrangian Connections between Observations within Air Masses Crossing the Atlantic during the ICARTT Experiment

    NASA Technical Reports Server (NTRS)

    Methven, J.; Arnold, S. R.; Stohl, A.; Evans, M. J.; Avery, M.; Law, K.; Lewis, A. C.; Monks, P. S.; Parrish, D.; Reeves, C.; Schlager, H.; Atlas, E.; Blake, D.; Coe, H.; Cohen, R. C.; Crosier, J.; Flocke, F.; Holloway, J. S.; Hopkins, J. R.; Huber, G.; McQuaid, J.; Purvis, R.; Rappengluck, B.; Ryerson, T. B.; Sachse, G. W.

    2006-01-01

    The International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)-Lagrangian experiment was conceived with an aim to quantify the effects of photochemistry and mixing on the transformation of air masses in the free troposphere away from emissions. To this end attempts were made to intercept and sample air masses several times during their journey across the North Atlantic using four aircraft based in New Hampshire (USA), Faial (Azores) and Creil (France). This article begins by describing forecasts using two Lagrangian models that were used to direct the aircraft into target air masses. A novel technique is then used to identify Lagrangian matches between flight segments. Two independent searches are conducted: for Lagrangian model matches and for pairs of whole air samples with matching hydrocarbon fingerprints. The information is filtered further by searching for matching hydrocarbon samples that are linked by matching trajectories. The quality of these coincident matches is assessed using temperature, humidity and tracer observations. The technique pulls out five clear Lagrangian cases covering a variety of situations and these are examined in detail. The matching trajectories and hydrocarbon fingerprints are shown and the downwind minus upwind differences in tracers are discussed.

  7. The Relationship of Loss, Mean Age of Air and the Distribution of CFC's to Stratospheric Circulation and Implications for Atmospheric Lifetimes

    NASA Technical Reports Server (NTRS)

    Douglas, A. R.; Stolarski, R. S.; Schoeberl, M. R.; Jackman, C. H.; Gupta, M. L.; Newman, P. A.; Nielsen, J. E.; Fleming, E. L.

    2008-01-01

    Model-derived estimates of the annually integrated destruction and lifetime for various ozone depleting substances (ODSs) depend on the simulated stratospheric transport and mixing in the global model used to produce the estimate. Observations in the middle and high latitude lower stratosphere show that the mean age of an air parcel (i.e., the time since its stratospheric entry) is related to the fractional release for the ODs (i.e., the amount of the ODS that has been destroyed relative to the amount at the time of stratospheric entry). We use back trajectory calculations to produce an age spectrum, and explain the relationship between the mean age and the fractional release by showing that older elements in the age spectrum have experienced higher altitudes and greater ODs destruction than younger elements. In our study, models with faster circulations produce distributions for the age-of-air that are 'young' compared to a distribution derived from observations. These models also fail to reproduce the observed relationship between the mean age of air and the fractional release. Models with slower circulations produce both realistic distributions for mean age and a realistic relationship between mean age and fractional release. These models also produce a CFCl3 lifetime of approximately 56 years, longer than the 45 year lifetime used to project future mixing ratios. We find that the use of flux boundary conditions in assessment models would have several advantages, including consistency between ODS evolution and simulated loss even if the simulated residual circulation changes due to climate change.

  8. Hemispheric asymmetries and seasonality of mean age of air in the lower stratosphere: Deep versus shallow branch of the Brewer-Dobson circulation

    NASA Astrophysics Data System (ADS)

    Konopka, Paul; Ploeger, Felix; Tao, Mengchu; Birner, Thomas; Riese, Martin

    2015-03-01

    Based on multiannual simulations with the Chemical Lagrangian Model of the Stratosphere, (CLaMS) driven by ECMWF ERA-Interim reanalysis, we discuss hemispheric asymmetries and the seasonality of the mean age of air (AoA) in the lower stratosphere. First, the planetary wave forcing of the Brewer-Dobson circulation is quantified in terms of Eliassen Palm flux divergence calculated by using the isentropic coordinate θ. While the forcing of the deep branch at θ = 1000 K (around 10 hPa) has a clear maximum in each hemisphere during the respective winter, the shallow branch of the Brewer-Dobson circulation, i.e., between 100 and 70 hPa (380 < θ < 420 K), shows almost opposite seasonality in both hemispheres with a pronounced minimum between June and September in the Southern Hemisphere. Second, we decompose the time-tendency of AoA into the contributions of the residual circulation and of eddy mixing by analyzing the zonally averaged tracer continuity equation. In the tropical lower stratosphere between ±30°, the air becomes younger during boreal winter and older during boreal summer. During boreal winter, the decrease of AoA due to tropical upwelling outweighs aging by isentropic mixing. In contrast, weaker isentropic mixing outweighs an even weaker upwelling in boreal summer and fall making the air older during these seasons. Poleward of 60°, the deep branch locally increases AoA and eddy mixing locally decreases AoA with the strongest net decrease during spring. Eddy mixing in the Northern Hemisphere outweighs that in the Southern Hemisphere throughout the year.

  9. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    USGS Publications Warehouse

    Friedman, I.; Harris, J.M.; Smith, G.I.; Johnson, C.A.

    2002-01-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (??D) and oxygen-18 (??18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  10. Mass spectrometry of solid samples in open air using combined laser ionization and ambient metastable ionization

    NASA Astrophysics Data System (ADS)

    He, X. N.; Xie, Z. Q.; Gao, Y.; Hu, W.; Guo, L. B.; Jiang, L.; Lu, Y. F.

    2012-01-01

    Mass spectrometry of solid samples in open air was carried out using combined laser ionization and metastable ionization time-of-flight mass spectrometry (LI-MI-TOFMS) in ambient environment for qualitative and semiquantitative (relative analyte information, not absolute information) analysis. Ambient metastable ionization using a direct analysis in realtime (DART) ion source was combined with laser ionization time-of-flight mass spectrometry (LI-TOFMS) to study the effects of combining metastable and laser ionization. A series of metallic samples from the National Institute of Standards and Technology (NIST 494, 495, 498, 499, and 500) and a pure carbon target were characterized using LI-TOFMS in open air. LI-MI-TOFMS was found to be superior to laser-induced breakdown spectroscopy (LIBS). Laser pulse energies between 10 and 200 mJ at the second harmonic (532 nm) of an Nd:YAG laser were applied in the experiment to obtain a high degree of ionization in plasmas. Higher laser pulse energy improves signal intensities of trace elements (such as Fe, Cr, Mn, Ni, Ca, Al, and Ag). Data were analyzed by numerically calculating relative sensitivity coefficients (RSCs) and limit of detections (LODs) from mass spectrometry (MS) and LIBS spectra. Different parameters, such as boiling point, ionization potential, RSC, LOD, and atomic weight, were shown to analyze the ionization and MS detection processes in open air.

  11. Study of single and combined mass-sensitive observables of cosmic ray induced extensive air showers

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, G.; Nemati, M.

    2016-03-01

    In this study, combinations of the global arrival time, (Δτ_{global}), pseudorapidity, and lateral density distribution (ρ_{μ}) of muons, which are three mass-sensitive observables of cosmic ray induced extensive air showers, have been used as new parameters to study the primary mass discrimination around the knee energies (100 TeV-10 PeV). This is a simulation-based study and the simulations have been performed for the KASCADE array at Karlsruhe and the Alborz-I array at Tehran to study the effect of the altitude on the quality of the primary mass discrimination. The merit factors of the single and combined three mass-sensitive observables have been calculated to compare the discrimination power of combined and single observables. We have used the CORSIKA 7.4 code to simulate the extensive air showers (EASs) sample sets. Considering all aspects of our study, it is found that the ratio of the global time to the lateral density distribution of the muons gives better results than other ratios; also in the case of single observables, the muon density gives better results compared with the other observables. Also it is shown that below 1 PeV primary energies, the ratio of the muon global time to the muon density (Δτ_{global}/ρ_{μ}) results in a better mass discrimination relative to the muon density only.

  12. Neonatal Presentation of an Air-Filled Neck Mass that Enlarges with Valsalva: A Case Report

    PubMed Central

    Patel, Jasminkumar Bharatbhai; Kilbride, Howard; Paulson, Lorien

    2015-01-01

    Branchial cleft cysts are common causes of congenital neck masses in the pediatric population. However, neonatal presentation of branchial cleft cysts is uncommon, but recognizable secondary to acute respiratory distress from airway compression or complications secondary to infection. We report a 1-day-old infant presenting with an air-filled neck mass that enlarged with Valsalva and was not associated with respiratory distress. The infant was found to have a third branchial cleft cyst with an internal opening into the pyriform sinus. The cyst was conservatively managed with endoscopic surgical decompression and cauterization of the tract and opening. We review the embryology of branchial cleft cysts and current management. PMID:26495186

  13. Measurement of mass attenuation coefficients in air by application of detector linearity tests

    NASA Astrophysics Data System (ADS)

    Peele, A. G.; Chantler, C. T.; Paterson, D.; McMahon, P. J.; Irving, T. H.; Lin, J. J.; Nugent, K. A.; Brunton, A. N.; McNulty, I.

    2002-10-01

    Accurate knowledge of x-ray mass attenuation coefficients is essential for studies as diverse as atomic physics, materials science, and radiation safety. However, a significant discrepancy exists between theoretical tabulated results for air at soft x-ray energies. We outline a precision measurement of the mass attenuation coefficients for air at various energies using two types of detectors and a simple test of detector response. We discuss whether sufficient accuracy can be obtained using this data to distinguish between competing theoretical estimates. In the process, we investigate the intensity response of two common synchrotron x-ray detectors: an x ray to optical charge-coupled device camera using a crystal scintillator and an x-ray sensitive photodiode.

  14. Estimation of whole lemon mass transfer parameters during hot air drying using different modelling methods

    NASA Astrophysics Data System (ADS)

    Torki-Harchegani, Mehdi; Ghanbarian, Davoud; Sadeghi, Morteza

    2015-08-01

    To design new dryers or improve existing drying equipments, accurate values of mass transfer parameters is of great importance. In this study, an experimental and theoretical investigation of drying whole lemons was carried out. The whole lemons were dried in a convective hot air dryer at different air temperatures (50, 60 and 75 °C) and a constant air velocity (1 m s-1). In theoretical consideration, three moisture transfer models including Dincer and Dost model, Bi- G correlation approach and conventional solution of Fick's second law of diffusion were used to determine moisture transfer parameters and predict dimensionless moisture content curves. The predicted results were then compared with the experimental data and the higher degree of prediction accuracy was achieved by the Dincer and Dost model.

  15. Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

    NASA Astrophysics Data System (ADS)

    Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

    2014-05-01

    Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

  16. Impacts of Typhoon and Air-Mass Pathways on Rainwater Chemical Compositions

    NASA Astrophysics Data System (ADS)

    Cheng, M.; You, C.

    2006-12-01

    To assess the importance of chemical fluxes on trace elements by wet precipitation, we have collected time- series rain waters between 06/20/04 and 09/20/05 for ICPMS and IC measurements. The sampling site is located at Tainan city in southwest Taiwan and there were four typhoons, namely Mindulle, Rananim, Aere, and Haima, hit the island during this period. Combining trace element compositions with HYSPLIT model for air-mass transportation designed by NOAA, we were able to understand possible source, flux and migration pathway of pollutants in rainwater. Our results show that seasalt contribution and trace element fluxes were higher during typhoon events. The Na and Pb flux varied largely, between 0.03~1388 and 0.0002~2000 mg/m2/day respectively, depended on the pathways of air mass trajectory and wind strength. It is clear that typhoons carry not only sea spray but also major anthropogenic pollutants from south Asia. Among the four typhoons, the Mindulle carried the largest fluxes of seasalt and trace elements while Rananim was weak in strength and brought the lowest Na and Pb due to less degree of mixing with air mass on land. The calculated enriched factors normalized to seawater (EFsea) were near unity for Na and Mg, but were much larger for K and Ca possibly due to crust source contamination and biomass burning. The EFcrust or EFsea values of various trace metals (e.g., V, Cr, Mn, Co, Ni, Cu, Zn, As, Ba and Pb were all significantly larger than 10 indicating the importance of anthropogenic sources. Interestingly, the PCA results confirm that rain waters with similar chemical characteristics have shared common air mass backward trajectory history.

  17. Trend analysis of air temperature time series in Greece and their relationship with circulation using surface and satellite data: recent trends and an update to 2013

    NASA Astrophysics Data System (ADS)

    Feidas, H.

    2016-07-01

    In this paper, the surface and lower tropospheric temperature trends in Greece and their relationship to the atmospheric circulation for the period 1955-2013 were examined, updating the study of Feidas et al. (Theor Appl Climatol 79:185-208, 2004) for data observed during the 12-year period 2002-2013. The trend analysis is based on a combination of three statistical tests. The trends are now examined for all the seasonal time series, new atmospheric circulation indices were added in the analysis, and maps with the spatial distribution of correlation between air temperature and atmospheric circulation were constructed and analysed. The series updated to 2013 for 18 stations reveal a clearer positive trend than that found for the period 1955-2001 on both the annual and the seasonal timescales. The warming signal detected only in summer in the study of Feidas et al. (Theor Appl Climatol 79:185-208, 2004) has now intensified and spread in other seasons. This warming appears to be mainly caused by the very high temperatures in the last decade (after 2004) of the record. At the national scale, there is now a match between surface temperature trends in Greece and Northern Hemisphere (NH) but only for summer, spring and annual time series, which are the only time series presenting a statistically significant warming trend in Greece. Satellite-induced lower tropospheric temperatures now show a statistically significant tropospheric temperature warming trend for the period 1979-2013, for both areas (Greece and NH). Lower tropospheric and surface air temperatures for the same period (1979-2013) show a very good agreement, with differences only in winter and summer for Greece. The influence of atmospheric circulation on the temperature variability in Greece was also examined using two more circulation indices: the Eastern Mediterranean Pattern Index (EMPI) and the North-Sea Caspian Pattern Index (NCPI). EMPI and especially NCPI explain better now the temperature variance in

  18. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    PubMed Central

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-01-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2− and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios. PMID:27033381

  19. Mass transfer characteristics of bisporus mushroom ( Agaricus bisporus) slices during convective hot air drying

    NASA Astrophysics Data System (ADS)

    Ghanbarian, Davoud; Baraani Dastjerdi, Mojtaba; Torki-Harchegani, Mehdi

    2016-05-01

    An accurate understanding of moisture transfer parameters, including moisture diffusivity and moisture transfer coefficient, is essential for efficient mass transfer analysis and to design new dryers or improve existing drying equipments. The main objective of the present study was to carry out an experimental and theoretical investigation of mushroom slices drying and determine the mass transfer characteristics of the samples dried under different conditions. The mushroom slices with two thicknesses of 3 and 5 mm were dried at air temperatures of 40, 50 and 60 °C and air flow rates of 1 and 1.5 m s-1. The Dincer and Dost model was used to determine the moisture transfer parameters and predict the drying curves. It was observed that the entire drying process took place in the falling drying rate period. The obtained lag factor and Biot number indicated that the moisture transfer in the samples was controlled by both internal and external resistance. The effective moisture diffusivity and the moisture transfer coefficient increased with increasing air temperature, air flow rate and samples thickness and varied in the ranges of 6.5175 × 10-10 to 1.6726 × 10-9 m2 s-1 and 2.7715 × 10-7 to 3.5512 × 10-7 m s-1, respectively. The validation of the Dincer and Dost model indicated a good capability of the model to describe the drying curves of the mushroom slices.

  20. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  1. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity.

    PubMed

    Bugbee, B; Monje, O; Tanner, B

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature. PMID:11538791

  2. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    NASA Astrophysics Data System (ADS)

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-04-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2‑ and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios.

  3. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways.

    PubMed

    Liu, D X; Liu, Z C; Chen, C; Yang, A J; Li, D; Rong, M Z; Chen, H L; Kong, M G

    2016-01-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H(+), nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2(-) and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios. PMID:27033381

  4. Seasonal variation of local atmospheric circulations and boundary layer structure in the Beijing-Tianjin-Hebei region and implications for air quality

    NASA Astrophysics Data System (ADS)

    Miao, Yucong; Hu, Xiao-Ming; Liu, Shuhua; Qian, Tingting; Xue, Ming; Zheng, Yijia; Wang, Shu

    2015-12-01

    The Beijing-Tianjin-Hebei (BTH) region experiences frequent heavy haze pollution in fall and winter. Pollution was often exacerbated by unfavorable atmospheric boundary layer (BL) conditions. The topography in this region impacts the BL processes in complex ways. Such impacts and implications on air quality are not yet clearly understood. The BL processes in all four seasons in BTH are thus investigated in this study using idealized simulations with the WRF-Chem model. Results suggest that seasonal variation of thermal conditions and synoptic patterns significantly modulates BL processes. In fall, with a relatively weak northwesterly synoptic forcing, thermal contrast between the mountains and the plain leads to a prominent mountain-plain breeze circulation (MPC). In the afternoon, the downward branch of the MPC, in addition to northwesterly warm advection, suppresses BL development over the western side of BTH. In the eastern coastal area, a sea-breeze circulation develops late in the morning and intensifies during the afternoon. In summer, southeasterly BL winds allow the see-breeze front to penetrate farther inland (˜150 km from the coast), and the MPC is less prominent. In spring and winter, with strong northwesterly synoptic winds, the sea-breeze circulation is confined in the coastal area, and the MPC is suppressed. The BL height is low in winter due to strong near-surface stability, while BL heights are large in spring due to strong mechanical forcing. The relatively low BL height in fall and winter may have exacerbated the air pollution, thus contributing to the frequent severe haze events in the BTH region.

  5. Influence of drying air parameters on mass transfer characteristics of apple slices

    NASA Astrophysics Data System (ADS)

    Beigi, Mohsen

    2016-10-01

    To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

  6. Influence of drying air parameters on mass transfer characteristics of apple slices

    NASA Astrophysics Data System (ADS)

    Beigi, Mohsen

    2015-12-01

    To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

  7. Comparison of the efficacy of a forced-air warming system and circulating-water mattress on core temperature and post-anesthesia shivering in elderly patients undergoing total knee arthroplasty under spinal anesthesia

    PubMed Central

    Lee, Kyu Chang; Lee, Myeong Jong; Kim, Mi-Na; Kim, Ji-Sub; Lee, Won Sang; Lee, Jung Hwa

    2014-01-01

    Background In the present study, we compared changes in body temperature and the occurrence of shivering in elderly patients undergoing total knee arthroplasty under spinal anesthesia during warming with either a forced-air warming system or a circulating-water mattress. Methods Forty-six patients were randomly assigned to either the forced-air warming system (N = 23) or circulating-water mattress (N = 23) group. Core temperature was recorded using measurements at the tympanic membrane and rectum. In addition, the incidence and intensity of post-anesthesia shivering and verbal analogue score for thermal comfort were simultaneously assessed. Results Core temperature outcomes did not differ between the groups. The incidence (13.0 vs 43.5%, P < 0.05) and intensity (20/2/1/0/0 vs 13/5/3/2/0, P < 0.05) of post-anesthesia shivering was significantly lower in the forced-air system group than in the circulating-water mattress group. Conclusions The circulating-water mattress was as effective as the forced-air warming system for maintaining body temperature. However, the forced-air warming system was superior to the circulating-water mattress in reducing the incidence of post-anesthesia shivering. PMID:24910726

  8. DNS and measurements of scalar transfer across an air-water interface during inception and growth of Langmuir circulation

    NASA Astrophysics Data System (ADS)

    Hafsi, A.; Ma, Y.; Buckley, M.; Tejada-Martinez, A. E.; Veron, F.

    2016-05-01

    Direct numerical simulations (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s have been conducted and scalar transfer from the air side to the water side and subsequent vertical transport in the water column have been analysed. Two simulations are compared: one with a freely deforming interface, giving rise to gravity-capillary waves and aqueous Langmuir turbulence (LT) characterized by small-scale (centimeter-scale) Langmuir cells (LC), and the other with the interface intentionally held flat, i.e., without LC. It is concluded that LT serves to enhance vertical transport of the scalar in the water side and in the process increases scalar transfer efficiency from the air side to the water side relative to the shear-dominated turbulence in the flat interface case. Furthermore, transition to LT was observed to be accompanied by a spike in scalar flux characterized by an order of magnitude increase. These episodic flux increases, if linked to gusts and overall unsteadiness in the wind field, are expected to be an important contributor in determining the long-term average of the air-sea gas fluxes.

  9. Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application.

    PubMed

    He, Jiuming; Tang, Fei; Luo, Zhigang; Chen, Yi; Xu, Jing; Zhang, Ruiping; Wang, Xiaohao; Abliz, Zeper

    2011-04-15

    Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI-MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability.

  10. Seasonality of new particle formation in Vienna, Austria - Influence of air mass origin and aerosol chemical composition

    NASA Astrophysics Data System (ADS)

    Wonaschütz, Anna; Demattio, Anselm; Wagner, Robert; Burkart, Julia; Zíková, Naděžda; Vodička, Petr; Ludwig, Wolfgang; Steiner, Gerhard; Schwarz, Jaroslav; Hitzenberger, Regina

    2015-10-01

    The impact of air mass origin and season on aerosol chemical composition and new particle formation and growth events (NPF events) in Vienna, Austria, is investigated using impactor samples from short-term campaigns and two long-term number size distribution datasets. The results suggest that air mass origin is most important for bulk PM concentrations, chemical composition of the coarse fraction (>1.5 μm) and the mass size distribution, and less important for chemical composition of the fine fraction (<1.5 μm). Continental air masses (crustal elements) were distinguished from air masses of marine origin (traces of sea salt). NPF events were most frequent in summer (22% of measurement days), and least frequent in winter (3% of measurement days). They were associated with above-average solar radiation and ozone concentrations, but were largely independent of PM2.5. Air mass origin was a secondary influence on NPF, largely through its association with meteorological conditions. Neither a strong dependence on the PM2.5 loading of the air masses, nor indications of a source area for NPF precursors outside the city were found.

  11. Community air monitoring for pesticides-part 2: multiresidue determination of pesticides in air by gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.

    PubMed

    Hengel, Matt; Lee, P

    2014-03-01

    Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography-mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37-104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70-170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air. PMID:24370860

  12. Optimization of solar cells for air mass zero operation and a study of solar cells at high temperatures, phase 2

    NASA Technical Reports Server (NTRS)

    Hovel, H.; Woodall, J. M.

    1976-01-01

    Crystal growth procedures, fabrication techniques, and theoretical analysis were developed in order to make GaAlAs-GaAs solar cell structures which exhibit high performance at air mass 0 illumination and high temperature conditions.

  13. Evidence for widespread tropospheric Cl chemistry in free tropospheric air masses from the South China Sea

    NASA Astrophysics Data System (ADS)

    Baker, Angela K.; Sauvage, Carina; Thorenz, Ute R.; Brenninkmeijer, Carl A. M.; Oram, David E.; van Velthoven, Peter; Zahn, Andreas; Williams, Jonathan

    2015-04-01

    While the primary global atmospheric oxidant is the hydroxyl radical (OH), under certain circumstances chlorine radicals (Cl) can compete with OH and perturb the oxidative cycles of the troposphere. During flights between Bangkok, Thailand and Kuala Lumpur, Malaysia conducted over two fall/winter seasons (November 2012 - March 2013 and November 2013 - January 2014) the IAGOS-CARIBIC (www.caribic-atmospheric.com) observatory consistently encountered free tropospheric air masses (9-11 km) originating over the South China Sea which had non-methane hydrocarbon (NMHC) signatures characteristic of processing by Cl. These signatures were observed in November and December of both years, but were not seen in other months, suggesting that oxidation by Cl is a persistent seasonal feature in this region. These Cl signatures were observed over a range of ~1500 km indicating a large-scale phenomenon. In this region, where transport patterns facilitate global redistribution of pollutants and persistent deep convection creates a fast-track for cross-tropopause transport, there exists the potential for regional chemistry to have impacts further afield. Here we use observed relationships between NMHCs to estimate the significance and magnitude of Cl oxidation in this region. From the relative depletions of NMHCs in these air masses we infer OH to Cl ratios of 83±28 to 139±40 [OH]/[Cl], which we believe represents an upper limit, based on the technique employed. At a predicted average [OH] of 1.5×106 OH cm-3 this corresponds to an average (minimum) [Cl] exposure of 1-2×104 Cl cm-3 during air mass transport. Lastly, in addition to estimating Cl abundances we have used IAGOS-CARIBIC observations to elucidate whether the origin of this Cl is predominantly natural or anthropogenic.

  14. The Breath of Planet Earth: Atmospheric Circulation. Assimilation of Surface Wind Observations

    NASA Technical Reports Server (NTRS)

    Atlas, Robert; Bloom, Stephen; Otterman, Joseph

    2000-01-01

    Differences in air pressure are a major cause of atmospheric circulation. Because heat excites the movement of atoms, warm temperatures cause, air molecules to expand. Because those molecules now occupy a larger space, the pressure that their weight exerts is decreased. Air from surrounding high-pressure areas is pushed toward the low-pressure areas, creating circulation. This process causes a major pattern of global atmosphere movement known as meridional circulation. In this form of convection, or vertical air movement, heated equatorial air rises and travels through the upper atmosphere toward higher latitudes. Air just above the equator heads toward the North Pole, and air just below the equator moves southward. This air movement fills the gap created where increased air pressure pushes down cold air. The ,cold air moves along the surface back toward the equator, replacing the air masses that rise there. Another influence on atmospheric. circulation is the Coriolis force. Because of the Earth's rotation, large-scale wind currents move in the direction of this axial spin around low-pressure areas. Wind rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. just as the Earth's rotation affects airflow, so too does its surface. In the phenomenon of orographic lifting, elevated topographic features such as mountain ranges lift air as it moves up their surface.

  15. Horizontal coring using air as the circulating fluid: Some prototype studies conducted in G Tunnel at the Nevada Test Site for the Yucca Mountain Project

    SciTech Connect

    Chornack, M.P.; French, C.A.

    1989-12-31

    Horizontal coring using air as the circulating fluid has been conducted in the G Tunnel Underground Facility (GTUF) at the Nevada Test Site. This work is part of the prototype investigations of hydrogeology for the Yucca Mountain Project. The work is being conducted to develop methods and procedures that will be used at the Department of Energy`s Yucca Mountain Site, a candidate site for the nation`s first high-level nuclear waste repository, during the site characterization phase of the investigations. The United States Geological Survey (USGS) is conducting this prototype testing under the guidance of the Los Alamos National Laboratory (LANL) and in conjunction with Reynolds Electrical & Engineering Company (REECo), the drilling contractor. 7 refs., 8 figs., 5 tabs.

  16. Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

    NASA Astrophysics Data System (ADS)

    Miller, Michael F.; Kessler, William J.; Allen, Mark G.

    1996-08-01

    An optical air mass flux sensor based on a compact, room-temperature diode laser in a fiber-coupled delivery system has been tested on a full-scale gas turbine engine. The sensor is based on simultaneous measurements of O 2 density and Doppler-shifted velocity along a line of sight across the inlet duct. Extensive tests spanning engine power levels from idle to full afterburner demonstrate accuracy and precision of the order of 1 2 of full scale in density, velocity, and mass flux. The precision-limited velocity at atmospheric pressure was as low as 40 cm s. Multiple data-reduction procedures are quantitatively compared to suggest optimal strategies for flight sensor packages.

  17. A combination of air and fluid drilling technique for zones of lost circulation in the Black Warrior Basin

    SciTech Connect

    Graves, S.L.; Niederhofer, J.D.; Beavers, W.M.

    1986-02-01

    Structural geologic information available for the coal-bearing formations in the Black Warrior basin documents the occurrence of numerous fault and fracture zones. A combination air/fluid drilling technique may be advantageous to coalbed-methane operations in this and other areas with similar hydrologic and geologic conditions. The authors successfully used this technique recently on coalbed-methane wells in Tuscaloosa County, AL.

  18. Characteristics of dimethylsulfide, ozone, aerosols, and cloud condensation nuclei in air masses over the northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Nagao, Ippei; Matsumoto, Kiyoshi; Tanaka, Hiroshi

    1999-05-01

    Long-term measurements of several trace gases and aerosols were carried out from December 1994 to October 1996 at Ogasawara Hahajima Island over the northwestern Pacific Ocean. The continental impact on the concentrations of sulfur compounds, ozone (O3), and cloud condensation nuclei (CCN) was estimated on the basis of the classification of air mass into seven types by isentropic trajectory analysis. From May to October, the air mass originating from the central North Pacific Ocean is predominant and regarded as the clean marine air for the concentrations of sulfur compounds and CCN. From the results of the molar ratio of methane sulfonic acid to non-sea-salt sulfate (NSS) and the positive correlation between dimethylsulfide (DMS) and CCN in this air mass it can be concluded that DMS largely contributes to the production of NSS and CCN. On the other hand, continental and anthropogenic substances are preferably transported to the northwestern Pacific Ocean by the predominant continental air mass from November to March. The enhancement of concentrations by the outflow from the Asian continent are estimated by a factor of 2.8 for O3, 3.9 for SO2, 3.5 for CCN activated at 0.5% supersaturation (0.5% CCN), 4.7 for 1.0% CCN, and 5.5 for NSS. Moreover, the CCN supersaturation spectra are also affected by the continental substances resulting in factor 2 of enhancement of cloud droplet number concentration. The diurnal variations of DMS and O3 for each air mass show a pattern of daytime minimum and nighttime maximum, which are typically found in remote ocean, even though those amplitudes are different for each air mass. Consequently, it can be concluded that the influence of nitric oxides (NOx) for the daytime O3 production and nitrate (NO3) radical for the nighttime oxidation of DMS are small even in the continental air mass.

  19. Solitary fibrous tumor of the pleura manifesting as an air-containing cystic mass: radiologic and histopathologic correlation.

    PubMed

    Baek, Ji Eun; Ahn, Myeong Im; Lee, Kyo Young

    2013-01-01

    Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that typically presents as a well-defined lobular soft tissue mass commonly arising from the pleura. We report an extremely rare case of an SFT containing air arising from the right major fissure in a 58-year-old woman. Chest CT showed an ovoid air-containing cystic mass with an internal, homogeneously enhancing solid nodule. To our knowledge, this is the first case in the literature. The histopathologic findings were correlated with the radiologic findings, and the mechanism of air retention within the tumor is discussed.

  20. Mixture model-based atmospheric air mass classification: a probabilistic view of thermodynamic profiles

    NASA Astrophysics Data System (ADS)

    Pernin, Jérôme; Vrac, Mathieu; Crevoisier, Cyril; Chédin, Alain

    2016-10-01

    Air mass classification has become an important area in synoptic climatology, simplifying the complexity of the atmosphere by dividing the atmosphere into discrete similar thermodynamic patterns. However, the constant growth of atmospheric databases in both size and complexity implies the need to develop new adaptive classifications. Here, we propose a robust unsupervised and supervised classification methodology of a large thermodynamic dataset, on a global scale and over several years, into discrete air mass groups homogeneous in both temperature and humidity that also provides underlying probability laws. Temperature and humidity at different pressure levels are aggregated into a set of cumulative distribution function (CDF) values instead of classical ones. The method is based on a Gaussian mixture model and uses the expectation-maximization (EM) algorithm to estimate the parameters of the mixture. Spatially gridded thermodynamic profiles come from ECMWF reanalyses spanning the period 2000-2009. Different aspects are investigated, such as the sensitivity of the classification process to both temporal and spatial samplings of the training dataset. Comparisons of the classifications made either by the EM algorithm or by the widely used k-means algorithm show that the former can be viewed as a generalization of the latter. Moreover, the EM algorithm delivers, for each observation, the probabilities of belonging to each class, as well as the associated uncertainty. Finally, a decision tree is proposed as a tool for interpreting the different classes, highlighting the relative importance of temperature and humidity in the classification process.

  1. Variation in particulate PAHs levels and their relation with the transboundary movement of the air masses.

    PubMed

    Ravindra, Khaiwal; Wauters, Eric; Van Grieken, René

    2008-06-25

    The levels of particulate polycyclic aromatic hydrocarbons (PAHs) were determined with a fast analytical approach to study their seasonal variations at Menen (Belgium) during 2003; they were found to be 5-7 times higher in January, February and December, in comparison to May, June and August. The annual average concentration of the sum of 16 US Environmental Protection Agency (EPA) criteria PAHs was 6.7 ng/m3 and around 63% of it was found to be probably carcinogenic to humans. The application of diagnostic ratio and principal component analysis showed vehicular emission as a major source. An increased ratio of 'combustion PAHs' to 'total EPA-PAHs' during the winter season indicated towards combustion activities. Further, the differences in PAHs concentration were assessed with relation to backward air mass trajectories, which show that the levels of PAHs increase when there is an air mass movement from Central and Western Europe and a fall when the trajectories spend most of their 4-day time over the Atlantic Ocean or in the Arctic region.

  2. Precipitation chemistry and corresponding transport patterns of influencing air masses at Huangshan Mountain in East China

    NASA Astrophysics Data System (ADS)

    Shi, ChunE; Deng, Xueliang; Yang, Yuanjian; Huang, Xiangrong; Wu, Biwen

    2014-09-01

    One hundred and ten samples of rainwater were collected for chemical analysis at the summit of Huangshan Mountain, a high-altitude site in East China, from July 2010 to June 2011. The volume-weighted-mean (VWM) pH for the whole sampling period was 5.03. SO{4/2-} and Ca2+ were the most abundant anion and cation, respectively. The ionic concentrations varied monthly with the highest concentrations in winter/spring and the lowest in summer. Evident inter-correlations were found among most ions, indicating the common sources for some species and fully mixing characteristics of the alpine precipitation chemistry. The VWM ratio of [SO{4/2-}]/[NO{3/-}] was 2.54, suggesting the acidity of rainwater comes from both nitric and sulfuric acids. Compared with contemporary observations at other alpine continental sites in China, the precipitation at Huangshan Mountain was the least polluted, with the lowest ionic concentrations. Trajectories to Huangshan Mountain on rainy days could be classified into six groups. The rainwater with influencing air masses originating in Mongolia was the most polluted with limited effect. The emissions of Jiangxi, Anhui, Zhejiang and Jiangsu provinces had a strong influence on the overall rain chemistry at Huangshan Mountain. The rainwater with influencing air masses from Inner Mongolia was heavily polluted by anthropogenic pollutants.

  3. Impact of maritime air mass trajectories on the Western European coast urban aerosol.

    PubMed

    Almeida, S M; Silva, A I; Freitas, M C; Dzung, H M; Caseiro, A; Pio, C A

    2013-01-01

    Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon, (2) identify the main sources of particles, (3) determine PM contribution to this urban area, and (4) assess the impact of maritime air mass trajectories on concentration and composition of respirable PM sampled in Lisbon. During 2007, PM2.5 was collected on a daily basis in the center of Lisbon with a Partisol sampler. The exposed Teflon filters were measured by gravimetry and cut into two parts: one for analysis by instrumental neutron activation analysis (INAA) and the other by ion chromatography (IC). Principal component analysis (PCA) and multilinear regression analysis (MLRA) were used to identify possible sources of PM2.5 and determine mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, calcium, soil, and sea. Four-day backtracking trajectories ending in Lisbon at the starting sampling time were calculated using the HYSPLIT model. Results showed that maritime transport scenarios were frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and exerted a significant role on air quality in this urban area.

  4. [Analysis of polycyclic aromatic hydrocarbons in air samples by gas chromatography-triple quadrupole mass spectrometry].

    PubMed

    Zhao, Bo; Li, Yuqing; Zhang, Sukun; Han, Jinglei; Xu, Zhencheng; Fang, Jiande

    2014-09-01

    A method of gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-MS/MS) has been optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in air samples. In the analysis step, isotope dilution was introduced to the quantification of PAHs. The GC-MS/MS method was applied to the analysis of the real air samples around a big petrochemical power plant in South China. The results were compared with those obtained by gas chromatography coupled to mass spectrometry (GC-MS). The results showed that better selectivity and sensitivity were obtained by GC-MS/MS. It was found that the external standard of deuterated-PAHs and internal standard of hexamethyl benzene were disturbed seriously with GC-MS, and the problems were both solved effectively by GC-MS/MS. Therefore more accurate quantification results of PAHs were obtained with GC-MS/MS. For the analysis of real samples, the RSDs of relative response factors ranged from 2.60% to 15.6% in standard curves; the recoveries of deuterated-PAHs ranged from 55.2% to 82.3%; the recoveries of spiked samples ranged from 98.9% to 111%; the RSDs of parallel specimens ranged from 6.50% to 18.4%; the concentrations of field blank samples ranged from not detected to 44.3 pg/m3; and the concentrations of library blank samples ranged from not detected to 36.5 pg/m3. The study indicated that the application of GC-MS/MS on the analysis of PAHs in air samples was recommended. PMID:25752088

  5. Air mass distribution and the heterogeneity of the climate change signal in the Hudson Bay/Foxe Basin region, Canada

    NASA Astrophysics Data System (ADS)

    Leung, Andrew; Gough, William

    2016-08-01

    The linkage between changes in air mass distribution and temperature trends from 1971 to 2010 is explored in the Hudson Bay/Foxe Basin region. Statistically significant temperature increases were found of varying spatial and temporal magnitude. Concurrent statistically significant changes in air mass frequency at the same locations were also detected, particularly in the declining frequency of dry polar (DP) air. These two sets of changes were found to be linked, and we thus conclude that the heterogeneity of the climatic warming signal in the region is at least partially the result of a fundamental shift in the concurrent air mass frequency in addition to global and regional changes in radiative forcing due to increases in long-lived greenhouse gases.

  6. Arctic Ocean circulation, processes and water masses: A description of observations and ideas with focus on the period prior to the International Polar Year 2007-2009

    NASA Astrophysics Data System (ADS)

    Rudels, Bert

    2015-03-01

    The evolving knowledge of the Arctic Ocean, its hydrography and its water masses and their transformations and circulation is reviewed starting with the observations made on Fram 1893-1896 and extending to the International Polar Year (IPY) 2007-2009. The expeditions and observations after Fram to the mid 20th century as well as the more extensive and systematic studies of water masses and circulation made from ice stations and airborne expeditions from the late 1940s to the late 1970s are briefly described. The early concepts of the connections and exchanges between the Arctic Ocean and the world ocean are also discussed. In the 1980s scientific icebreakers were beginning to enter the inner parts of the Arctic Ocean and large international programmes were launched, culminating in the IPY. The changes in the Arctic Ocean, first noted in the Atlantic layer in 1990 and shortly after in the upper layers, are described. The exchanges between the Arctic Ocean and the surrounding seas through the four main openings, Fram Strait, Barents Sea, Bering Strait and the Canadian Arctic Archipelago as well the volume and freshwater balances of the Arctic Ocean are examined.

  7. The South Asian Monsoon Circulation in Moist Isentropic coordinates

    NASA Astrophysics Data System (ADS)

    Thazhe Purayil, Sabin; Pauluis, Olivier

    2016-04-01

    The atmospheric circulation and thermodynamic structure during the South Asian Summer Monsoon season is analyzed in isentropic coordinates through the mass transport represented in terms of the potential temperature and equivalent potential temperature. This approach, originally developed to analyze the global meridional circulation, makes it possible to identify the thermodynamic properties of the inflow and outflow of different air mass. To understand the thermodynamic properties of air mass in south Asian monsoon region, we have used three diagnostics; a) the joint distribution of the mass transport as a function of dry and moist entropy, b) the vertical mass flux over the monsoon domain and c) the mass transport and isentropic thickness for different moist ventilation range of tropical atmosphere. The thermodynamic properties of the various air masses, such as the inflow of warm moist air in the boundary layer, upper tropospheric outflow, and midlatitude dry air intrusion are being systematically identified. The isentropic distribution of the vertical mass flux transport in terms of equivalent potential temperature is used to explain the characteristics of ascending and descending air parcels over the Indian subcontinent. Diagnosis based on the isentropic thickness reveals that the regional monsoon circulation and associated precipitation features can be systematically explained by this method. This technique is used to study the evolution of the monsoon flow in the seasonal scale. We used the data from AMIP-type simulations carried out with prescribed Sea Surface Temperature and sea ice for a 25 year period (1981-2005) from the GFDL High-resolution atmospheric model (HiRAM) with an average grid spacing of ~25km over the globe.

  8. Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

    PubMed

    Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

    2016-05-15

    This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins.

  9. Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

    PubMed

    Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

    2016-05-15

    This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins. PMID:26930305

  10. Quantification of methane in humid air and exhaled breath using selected ion flow tube mass spectrometry.

    PubMed

    Dryahina, Kseniya; Smith, D; Spanel, P

    2010-05-15

    In selected ion flow tube mass spectrometry, SIFT-MS, analyses of humid air and breath, it is essential to consider and account for the influence of water vapour in the media, which can be profound for the analysis of some compounds, including H(2)CO, H(2)S and notably CO(2). To date, the analysis of methane has not been considered, since it is known to be unreactive with H(3)O(+) and NO(+), the most important precursor ions for SIFT-MS analyses, and it reacts only slowly with the other available precursor ion, O(2) (+). However, we have now experimentally investigated methane analysis and report that it can be quantified in both air and exhaled breath by exploiting the slow O(2) (+)/CH(4) reaction that produces CH(3)O(2) (+) ions. We show that the ion chemistry is significantly influenced by the presence of water vapour in the sample, which must be quantified if accurate analyses are to be performed. Thus, we have carried out a study of the loss rate of the CH(3)O(2) (+) analytical ion as a function of sample humidity and deduced an appropriate kinetics library entry that provides an accurate analysis of methane in air and breath by SIFT-MS. However, the associated limit of detection is rather high, at 0.2 parts-per-million, ppm. We then measured the methane levels, together with acetone levels, in the exhaled breath of 75 volunteers, all within a period of 3 h, which shows the remarkable sample throughput rate possible with SIFT-MS. The mean methane level in ambient air is seen to be 2 ppm with little spread and that in exhaled breath is 6 ppm, ranging from near-ambient levels to 30 ppm, with no significant variation with age and gender. Methane can now be included in the wide ranging analyses of exhaled breath that are currently being carried out using SIFT-MS.

  11. Aerosols in Polluted versus Nonpolluted Air Masses: Long-Range Transport and Effects on Clouds.

    NASA Astrophysics Data System (ADS)

    Pueschel, R. F.; van Valin, C. C.; Castillo, R. C.; Kadlecek, J. A.; Ganor, E.

    1986-12-01

    To assess the influence of anthropogenic aerosols on the physics and chemistry of clouds in the northeastern United State, aerosol and cloud-drop size distributions, elemental composition of aerosols as a function of size, and ionic content of cloud water were measured on Whiteface Mountain, New York, during the summers of 1981 and 1982. In several case studies, the data were cross-correlated with different air mass types-background continental, polluted continental, and maritime-that were advected to the sampling site. The results are the following (1) Anthropogenic sources hundreds of kilometers upwind cause the small-particle (accumulation) mode number to increase from hundreds to thousands per cubic centimeter and the mass loading to increase from a few to several tens of micrograms per cubic meter, mostly in the form of sulfur aerosols. (ii) A significant fraction of anthropogenic sulfur aerosols appears to act as cloud condensation nuclei (CCN) to affect the cloud drop concentration. (iii) Clouds in Atlantic maritime air masses have cloud drop spectra that are markedly different from those measured in continental clouds. The drop concentration is significantly lower, and the drop size spectra are heavily skewed toward large drops. (iv) Effects of anthropogenic pollutants on cloud water ionic composition are an increase of nitrate by a factor of 50, an increase of sulfate by more than one order of magnitude, and an increase of ammonium ion by a factor of 7. The net effect of the changes in ionic concentrations is an increase in cloud water acidity. An anion deficit even in maritime clouds suggests an unknown, possibly biogenic, source that could be responsible for a pH below neutral, which is frequently observed in nonpolluted clouds.

  12. Finite element analysis of an inflatable torus considering air mass structural element

    NASA Astrophysics Data System (ADS)

    Gajbhiye, S. C.; Upadhyay, S. H.; Harsha, S. P.

    2014-01-01

    Inflatable structures, also known as gossamer structures, are at high boom in the current space technology due to their low mass and compact size comparing to the traditional spacecraft designing. Internal pressure becomes the major source of strength and rigidity, essentially stiffen the structure. However, inflatable space based membrane structure are at high risk to the vibration disturbance due to their low structural stiffness and material damping. Hence, the vibration modes of the structure should be known to a high degree of accuracy in order to provide better control authority. In the past, most of the studies conducted on the vibration analysis of gossamer structures used inaccurate or approximate theories in modeling the internal pressure. The toroidal shaped structure is one of the important key element in space application, helps to support the reflector in space application. This paper discusses the finite-element analysis of an inflated torus. The eigen-frequencies are obtained via three-dimensional small-strain elasticity theory, based on extremum energy principle. The two finite-element model (model-1 and model-2) have cases have been generated using a commercial finite-element package. The structure model-1 with shell element and model-2 with the combination of the mass of enclosed fluid (air) added to the shell elements have been taken for the study. The model-1 is computed with present analytical approach to understand the convergence rate and the accuracy. The convergence study is made available for the symmetric modes and anti-symmetric modes about the centroidal-axis plane, meeting the eigen-frequencies of an inflatable torus with the circular cross section. The structural model-2 is introduced with air mass element and analyzed its eigen-frequency with different aspect ratio and mode shape response using in-plane and out-plane loading condition are studied.

  13. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Moltham, A. L.; Folmer, M. J.; Jedlovec, G. J.

    2014-01-01

    The investigation of non-convective winds associated with passing extratropical cyclones and the formation of the sting jet in North Atlantic cyclones that impact Europe has been gaining interest. Sting jet research has been limited to North Atlantic cyclones that impact Europe because it is known to occur in Shapiro-Keyser cyclones and theory suggests it does not occur in Norwegian type cyclones. The global distribution of sting jet cyclones is unknown and questions remain as to whether cyclones with Shapiro-Keyser characteristics that impact the United States develop features similar to the sting jet. Therefore unique National Aeronautics and Space Administration (NASA) products were used to analyze an event that impacted the Northeast United States on 09 February 2013. Moderate Resolution Imaging Spectroradiometer (MODIS) Red Green Blue (RGB) Air Mass imagery and Atmospheric Infrared Sounder (AIRS) ozone data were used in conjunction with NASA's global Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis and higher-resolution regional 13-km Rapid Refresh (RAP) data to analyze the role of stratospheric air in producing high winds. The RGB Air Mass imagery and a new AIRS ozone anomaly product were used to confirm the presence of stratospheric air. Plan view and cross sectional plots of wind, potential vorticity, relative humidity, omega, and frontogenesis were used to analyze the relationship between stratospheric air and high surface winds during the event. Additionally, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to plot trajectories to determine the role of the conveyor belts in producing the high winds. Analyses of new satellite products, such as the RGB Air Mass imagery, show the utility of future GOES-R products in forecasting non-convective wind events.

  14. Fullerene Soot in Eastern China Air: Results from Soot Particle-Aerosol Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Wang, J.; Ge, X.; Chen, M.; Zhang, Q.; Yu, H.; Sun, Y.; Worsnop, D. R.; Collier, S.

    2015-12-01

    In this work, we present for the first time, the observation and quantification of fullerenes in ambient airborne particulate using an Aerodyne Soot Particle - Aerosol Mass Spectrometer (SP-AMS) deployed during 2015 winter in suburban Nanjing, a megacity in eastern China. The laser desorption and electron impact ionization techniques employed by the SP-AMS allow us to differentiate various fullerenes from other aerosol components. Mass spectrum of the identified fullerene soot is consisted by a series of high molecular weight carbon clusters (up to m/z of 2000 in this study), almost identical to the spectral features of commercially available fullerene soot, both with C70 and C60 clusters as the first and second most abundant species. This type of soot was observed throughout the entire study period, with an average mass loading of 0.18 μg/m3, accounting for 6.4% of the black carbon mass, 1.2% of the total organic mass. Temporal variation and diurnal pattern of fullerene soot are overall similar to those of black carbon, but are clearly different in some periods. Combining the positive matrix factorization, back-trajectory and analyses of the meteorological parameters, we identified the petrochemical industrial plants situating upwind from the sampling site, as the major source of fullerene soot. In this regard, our findings imply the ubiquitous presence of fullerene soot in ambient air of industry-influenced area, especially the oil and gas production regions. This study also offers new insights into the characterization of fullerenes from other environmental samples via the advanced SP-AMS technique.

  15. The Relationship of Loss, Mean Age of Air and the Distribution of CFCs to Stratospheric Circulation and Implications for Atmospheric Lifetimes

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Stolarski, R. S.; Schoeberl, M. R.; Jackman, C. H.; Guptal, M. L.; Newman, P. A.; Nielsen, J. E.; Fleming, E. L.

    2007-01-01

    Man-made molecules called chlorofluorcarbons (CFCs) are broken apart in the stratosphere by high energy light, and the reactive chlorine gases that come from them cause the ozone hole. Since the ozone layer stops high energy light from reaching low altitudes, CFCs must be transported to high altitudes to be broken apart. The number of molecules per volume (the density) is much smaller at high altitudes than near the surface, and CFC molecules have a very small chance of reaching that altitude in any particular year. Many tons of CFCs were put into the atmosphere during the end of the last century, and it will take many years for all of them to be destroyed. Each CFC has an atmospheric lifetime that depends on the amount of energy required to break them apart. Two of the gases that were made the most are CFC13 and CF2C12. It takes more energy to break apart CF2C12 than CFC13, and its lifetime is about 100 years, nearly twice as long as the lifetime for CFC13. It is hard to figure out the lifetimes from surface measurements because we don't know exactly how much was released into the air each year. Atmospheric models are used to predict what will happen to ozone and other gases as the CFCs decrease and other gases like C02 continue to increase during the next century. CFC lifetimes are used to predict future concentrations and all assessment models use the predicted future concentrations. The models have different circulations and the amount of CFC lost according to the model may not match the loss that is expected according to the lifetime. In models the amount destroyed per year depends on how fast the model pushes air into the stratosphere and how much goes to high altitudes each year. This paper looks at the way the model circulation changes the lifetimes, and looks at measurements that tell us which model is more realistic. Some models do a good job reproducing the age-of-air, which tells us that these models are circulating the stratospheric air at the right

  16. Number size distribution of aerosols at Mt. Huang and Nanjing in the Yangtze River Delta, China: Effects of air masses and characteristics of new particle formation

    NASA Astrophysics Data System (ADS)

    Wang, Honglei; Zhu, Bin; Shen, Lijuan; An, Junlin; Yin, Yan; Kang, Hanqing

    2014-12-01

    Aerosol number spectra in the range of 10 nm-10 μm were observed at Mt. Huang (Aug. 15-Sep. 15) and Nanjing (Oct. 13-Nov. 15) by a wide-range particle spectrometer (WPS) in 2011. Based on the backward trajectories obtained using the HYSPLIT model, the transport pathways of observed air masses during the study periods were classified into the following four groups: maritime air mass, continental air mass, marine-continental mixed air mass and local air mass. The variations in the aerosol number spectrum and the new particle formation (NPF) events for various types of air masses were discussed, along with meteorological data. The results showed that the average number concentration was 12,540 cm- 3 at Nanjing and only 2791 cm- 3 at Mt. Huang. The aerosol number concentration in Nanjing was 3-7 times higher than that in Mt. Huang; the large discrepancy was in the range of 10-100 nm. Different types of air masses had different effects on number concentration distribution. The number concentration of aerosols was higher in marine air masses, continental air masses and continental-marine mixed air masses at 10-50 nm, 100-500 nm and 50-200 nm, respectively. Under the four types of air masses, the aerosol size spectra had bimodal distributions in Nanjing and unimodal distributions in Mt. Huang (except under continental air masses: HT1). The effects of the diverse air masses on aerosol size segments of the concentration peak in Mt. Huang were stronger than those in Nanjing. The local air masses were dominant at these two sites and accounted for 44% of the total air masses. However, the aerosol number concentration was the lowest in Mt. Huang and the highest in Nanjing when local air masses were present. The number concentrations for foreign air masses increased at Mt. Huang and decreased at Nanjing. Different types of air masses had greater effects on the aerosol spectrum distribution at Mt. Huang than at Nanjing. During the NPF events, the particle growth rates at Mt

  17. Circulation factors affecting precipitation over Bulgaria

    NASA Astrophysics Data System (ADS)

    Nojarov, Peter

    2015-09-01

    The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, showing west-east or south-north transport of air masses over Bulgaria and four teleconnection indices (patterns)—North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian. Omega values at 700-hPa level show vertical motions in the atmosphere. Annual precipitation trends are mixed and not statistically significant. A significant decrease of precipitation in Bulgaria is observed in November due to the strengthening of the eastward transport of air masses (strengthening of EA teleconnection pattern) and anticyclonal weather (increase of descending motions in the atmosphere). There is also a precipitation decrease in May and June due to the growing influence of the Azores High. An increase of precipitation happens in September. All this leads to a redistribution of annual precipitation course, but annual precipitation amounts remain the same. However, this redistribution has a negative impact on agriculture and winter ski tourism. Zonal circulation has a larger influence on precipitation in Bulgaria compared to meridional. Eastward transport throughout the year leads to lower than the normal precipitation, and vice versa. With regard to the four teleconnection patterns, winter precipitation in Bulgaria is determined mainly by EA/WR teleconnection pattern, spring and autumn by EA teleconnection pattern, and summer by SCAND teleconnection pattern.

  18. An Air Mass Based Approach to the Establishment of Spring Season Synoptic Characteristics in the Northeast United States

    NASA Astrophysics Data System (ADS)

    Zander, R.; Messina, A.; Godek, M. L.

    2012-12-01

    The spring season is indicative of marked meteorological, ecological, and biological changes across the Northeast United States. The onset of spring coincides with distinct meteorological phenomena including an increase in severe weather events and snow meltwaters that can cause localized flooding and other costly damages. Increasing and variable springtime temperatures also influence Northeast tourist operations and agricultural productivity. Even with the vested interest of industry in the season and public awareness of the dynamic characteristics of spring, the definition of spring remains somewhat arbitrary. The primary goal of this research is to obtain a synoptic meteorological definition of the spring season through an assessment of air mass frequency over the past 60 years. A secondary goal examines the validity of recent speculations that the onset and termination of spring has changed in recent decades, particularly since 1975. The Spatial Synoptic Classification is utilized to define daily air masses over the region. Annual and seasonal baseline frequencies are identified and their differences are acquired to characterize the season. Seasonal frequency departures of the early and late segments of the period of record around 1975 are calculated and examined for practical and statistical significance. The daily boundaries of early and late spring are then isolated and frequencies are obtained for these periods. Boundary frequencies are assessed across the period of record to identify important changes in the season's initiation and termination through time. Results indicate that the Northeast spring season is dominated by dry air masses, mainly the Dry Moderate and Dry Polar types. Significant differences in seasonal air mass frequency are also observed through time. Prior to 1975, higher frequencies of polar air mass types are detected while after 1975 there is an increase in the frequencies of both moderate and tropical types. This finding is also

  19. Atmospheric Thickness Variability During Air Mass Conditions and Winter Snow Events at Albany, NY: 2002-2012

    NASA Astrophysics Data System (ADS)

    Dubbs, A. M.; Swift, S.; Godek, M. L.

    2014-12-01

    A winter weather parameter that is underutilized in the prediction of Northeast snowfall events is critical thickness. Knowledge of atmospheric thickness values during snowfall can benefit the accuracy of winter forecasts, especially if thickness layer ranges at times without precipitation are known. This investigation aims to better understand atmospheric thickness variations in the 1000-500, 1000-700, and 1000-850 hPa layers at Albany, New York during snowfall with differing air mass conditions. Since snow can occur alongside a variety of air mass environments, distinctions in layer thickness between air mass types and critical levels will be examined. Pairing air mass information with an improved understanding of thicknesses may allow forecasters to determine normal snowfall conditions of the atmosphere and decipher when anomalous conditions are occurring alongside heavier snows. Daily geopotential height data are examined alongside Spatial Synoptic Classification weather types over the past decade. Air mass frequencies are computed and baseline thicknesses are established for non-snow days, days with snow and liquid precipitation, and days with only snowfall. Thicknesses are compared to those computed for seven air mass types and differences layers are examined for continuity. For the three air masses identified as prevalent during heavy snow, light-to-heavy and early-to-late season snowfall categories are established and thickness variations are evaluated against non-snow days for significant differences. Results indicate that the differences in layer thicknesses are comparable for all precipitation and non-snow days but around 40 geopotential meters less for pure-snow days. For air masses present during snow, layer thicknesses can vary by over 100 gpm with type. Isolating polar varieties, approximately 50 gpm thickness differences are found in pure-snow days. Comparable differences are detected between the moderate and polar types and the continuity between

  20. Upper Air Temperature and Circulation Climatologies from GPS Radio Occultation Measurements for Climate Process Studies and Model Evaluation

    NASA Astrophysics Data System (ADS)

    Ao, C. O.; Verkhoglyadova, O. P.; Mannucci, A. J.; Leroy, S. S.

    2014-12-01

    GPS radio occultation (RO) measurements are known to yield highly accurate temperature and geopotential height in the upper troposphere and lower stratosphere (UTLS) with 200 m vertical resolution in all-weather conditions. With over twelve years (2001-present) of continuous GPS RO measurements now available from CHAMP, COSMIC, and other missions, the dataset has become increasingly valuable in the study of upper air climate trend, variability, and processes. In this presentation, we will describe our approach towards the generation of global monthly gridded data products that include temperature, geopotential height, and geostrophic wind in the UTLS. To interpolate or map the irregularly sampled RO data into a 2D grid, a Bayesian method with spherical harmonic basis functions is implemented. Furthermore, we will quantify the measurement and sampling uncertainty associated with the monthly gridded data. Applications of the dataset in the variability of the tropical belt and CMIP5 model evaluation will be presented. In addition, we will discuss recent progress in reducing systematic retrieval errors as well as efforts to extend the current data record rigorously to the GPS/MET era (1995-1997).

  1. The mesoscale forcing of a midlatitude upper-tropospheric jet streak by a simulated convective system. 1: Mass circulation and ageostrophic processes

    NASA Technical Reports Server (NTRS)

    Wolf, Bart J.; Johnson, D. R.

    1995-01-01

    The mutual forcing of a midlatitude upper-tropospheric jet streak by organized mesoscale adiabatic and diabatic processes within a simulated convective system (SCS) is investigated. Using isentropic diagnostics, results from a three-dimensional numerical simulation of an SCS are examined to study the isallobaric flow field, modes of dominant ageostrophic motion, and stability changes in relation to the mutual interdependence of adiabatic processes and latent heat release. Isentropic analysis affords an explicit isolation of a component of isallobaric flow associated with diabatic processes within the SCS. Prior to convective development within the simulations, atmospheric destabilization occurs through adiabatic ageostrophic mass adjustment and low-level convergence in association with the preexisting synoptic-scale upper-tropospheric jet streak. The SCS develops in a baroclinic zone and quickly initiates a vigorous mass circulation. By the mature stage, a pronounced vertical couplet of low-level convergence and upper-level mass divergence is established, linked by intense midtropospoheric diabatic heating. Significant divergence persists aloft for several hours subsequent to SCS decay. The dominant role of ageostrophic motion within which the low-level mass convergence develops is the adiabatic isallobaric component, while the mass divergence aloft develops principally through the diabatic isallobaric component. Both compnents are intrinsically linked to the convectively forced vertical mass transport. The inertial diabatic ageostrophic component is largest near the level of maximum heating and is responsible for the development of inertial instability to the north of SCS, resulting in this quadrant being preferred for outflow. The inertial advective component, the dominant term that produces the new downstream wind maximum, rapidly develops north of the SCS and through mutual adjustment creates the baroclinic support for the new jet streak.

  2. Composition of air masses in Fuerteventura (Canary Islands) according to their origins

    SciTech Connect

    Patier, R.F.; Diez Hernandez, P.; Diaz Ramiro, E.; Ballesteros, J.S.; Santos-Alves, S.G. dos

    1994-12-31

    The Centro Nacional de Sanidad Ambiental has among their duties the background atmospheric pollution monitoring in Spain. To do so, the laboratory has set up 6 field stations in the Iberian Peninsula. In these stations, both gaseous and particulate pollutants are currently analyzed. However, there is a lack of data about the atmospheric pollution in the Canary, where they are a very strong influence of natural emissions from sea and the Saharan desert, mixed with anthropogenic ones. Therefore, during the ASTEX/MAGE project the CNSA established a station in Fuerteventura island, characterized by the nonexistence of man-made emissions, to measure some atmospheric pollutants, in order to foresee their origins. In this study, the authors analyzed some pollutants that are used to obtain a clue about the sources of air masses such as gaseous ozone and metallic compounds (vanadium, iron and manganese) in the atmospheric aerosol fractionated by size.

  3. Operational performance of a low cost, air mass 2 solar simulator

    NASA Technical Reports Server (NTRS)

    Yass, K.; Curtis, H. B.

    1975-01-01

    Modifications and improvements on a low cost air mass 2 solar simulator are discussed. The performance characteristics of total irradiance, uniformity of irradiance, spectral distribution, and beam subtense angle are presented. The simulator consists of an array of tungsten halogen lamps hexagonally spaced in a plane. A corresponding array of plastic Fresnel lenses shapes the output beam such that the simulator irradiates a 1.2 m by 1.2 m area with uniform collimated irradiance. Details are given concerning individual lamp output measurements and placement of the lamps. Originally, only the direct component of solar irradiance was simulated. Since the diffuse component may affect the performance of some collectors, the capability to simulate it is being added. An approach to this diffuse addition is discussed.

  4. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  5. Simultaneous measurement of mass and rotation of trapped absorbing particles in air.

    PubMed

    Bera, Sudipta K; Kumar, Avinash; Sil, Souvik; Saha, Tushar Kanti; Saha, Tanumoy; Banerjee, Ayan

    2016-09-15

    We trap absorbing micro-particles in air by photophoretic forces generated using a single loosely focused Gaussian trapping beam. We measure a component of the radial Brownian motion of a trapped particle cluster and determine the power spectral density, mean squared displacement, and normalized position and velocity autocorrelation functions to characterize the photophoretic body force in a quantitative fashion for the first time. The trapped particles also undergo spontaneous rotation due to the action of this force. This is evident from the spectral density that displays clear peaks at the rotation and the particles' inertial resonance frequencies. We fit the spectral density to the well-known analytical function derived from the Langevin equation, measure the resonance and rotation frequencies, and determine the values for particle mass that we verify at different trapping laser powers with reasonable accuracy. PMID:27628396

  6. Identification of aerosol types over an urban site based on air-mass trajectory classification

    NASA Astrophysics Data System (ADS)

    Pawar, G. V.; Devara, P. C. S.; Aher, G. R.

    2015-10-01

    Columnar aerosol properties retrieved from MICROTOPS II Sun Photometer measurements during 2010-2013 over Pune (18°32‧N; 73°49‧E, 559 m amsl), a tropical urban station in India, are analyzed to identify aerosol types in the atmospheric column. Identification/classification is carried out on the basis of dominant airflow patterns, and the method of discrimination of aerosol types on the basis of relation between aerosol optical depth (AOD500 nm) and Ångström exponent (AE, α). Five potential advection pathways viz., NW/N, SW/S, N, SE/E and L have been identified over the observing site by employing the NOAA-HYSPLIT air mass back trajectory analysis. Based on AE against AOD500 nm scatter plot and advection pathways followed five major aerosol types viz., continental average (CA), marine continental average (MCA), urban/industrial and biomass burning (UB), desert dust (DD) and indeterminate or mixed type (MT) have been identified. In winter, sector SE/E, a representative of air masses traversed over Bay of Bengal and Eastern continental Indian region has relatively small AOD (τpλ = 0.43 ± 0.13) and high AE (α = 1.19 ± 0.15). These values imply the presence of accumulation/sub-micron size anthropogenic aerosols. During pre-monsoon, aerosols from the NW/N sector have high AOD (τpλ = 0.61 ± 0.21), and low AE (α = 0.54 ± 0.14) indicating an increase in the loading of coarse-mode particles over Pune. Dominance of UB type in winter season for all the years (i.e. 2010-2013) may be attributed to both local/transported aerosols. During pre-monsoon seasons, MT is the dominant aerosol type followed by UB and DD, while the background aerosols are insignificant.

  7. AUTOMATED DECONVOLUTION OF COMPOSITE MASS SPECTRA OBTAINED WITH AN OPEN-AIR IONIZATIONS SOURCE BASED ON EXACT MASSES AND RELATIVE ISOTIPIC ABUNDANCES

    EPA Science Inventory

    Chemicals dispersed by accidental, deliberate, or weather-related events must be rapidly identified to assess health risks. Mass spectra from high levels of analytes obtained using rapid, open-air ionization by a Direct Analysis in Real Time (DART®) ion source often contain

  8. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    SciTech Connect

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  9. Ring waves as a mass transport mechanism in air-driven core-annular flows.

    PubMed

    Camassa, Roberto; Forest, M Gregory; Lee, Long; Ogrosky, H Reed; Olander, Jeffrey

    2012-12-01

    Air-driven core-annular fluid flows occur in many situations, from lung airways to engineering applications. Here we study, experimentally and theoretically, flows where a viscous liquid film lining the inside of a tube is forced upwards against gravity by turbulent airflow up the center of the tube. We present results on the thickness and mean speed of the film and properties of the interfacial waves that develop from an instability of the air-liquid interface. We derive a long-wave asymptotic model and compare properties of its solutions with those of the experiments. Traveling wave solutions of this long-wave model exhibit evidence of different mass transport regimes: Past a certain threshold, sufficiently large-amplitude waves begin to trap cores of fluid which propagate upward at wave speeds. This theoretical result is then confirmed by a second set of experiments that show evidence of ring waves of annular fluid propagating over the underlying creeping flow. By tuning the parameters of the experiments, the strength of this phenomenon can be adjusted in a way that is predicted qualitatively by the model.

  10. Synoptic patterns and air mass transport during ozone episodes in northwestern Iberia.

    PubMed

    Saavedra, S; Rodríguez, A; Taboada, J J; Souto, J A; Casares, J J

    2012-12-15

    High levels of ozone are frequently measured at the Galicia (NW Iberian Peninsula) air quality monitoring stations from March to October. However, there have been very few studies on surface ozone in the northwestern Iberian Peninsula, most likely because the climate of this region is not favourable to photochemical ozone generation. The occurrence of these episodes may be related to either local-scale photochemical pollution or regional-scale transport from other polluted regions. In addition, high ozone episodes usually are developed under specific synoptic conditions. The main purposes of this study are to characterise the atmospheric conditions that lead to the ozone episodes in this region and to identify possible advection paths of ozone and precursors. A surface hourly ozone dataset (2002-2007) measured at rural sites in Galicia was analysed to identify high ozone episodes together with their associated synoptic patterns using a subjective classification with 23 different synoptic types. The synoptic weather patterns revealed that most of the episodes occur with high surface pressures centred over the British Isles and/or Central Europe while a high-altitude anticyclonic ridge crosses the Peninsula from North Africa, causing easterly or southeasterly winds. This analysis was completed with 3-day backward air mass trajectories obtained with HYSPLIT to assess the contribution of long-range transport, resulting in the following main routes: Mediterranean-Peninsular, South Atlantic-Portuguese, local and French-Cantabric.

  11. Enantiomeric signatures of organochlorine pesticides in Asian, trans-Pacific, and western U.S. air masses.

    PubMed

    Genualdi, Susan A; Simonich, Staci L Massey; Primbs, Toby K; Bidleman, Terry F; Jantunen, Liisa M; Ryoo, Keon-Sang; Zhu, Tong

    2009-04-15

    The enantiomeric signatures of organochlorine pesticides were measured in air masses from Okinawa, Japan and three remote locations in the Pacific Northwestern United States: Cheeka Peak Observatory (CPO), a marine boundary layer site on the Olympic Peninsula of Washington at 500 m above sea level (m.a.s.l); Mary's Peak Observatory (MPO), a site at 1250 m.a.s.l in Oregon's Coast range; and Mt. Bachelor Observatory (MBO), a site at 2763 m.a.s.l in Oregon's Cascade range. The enantiomeric signatures of composite soil samples, collected from China, South Korea, and the western U.S. were also measured. The data from chiral analysis was expressed asthe enantiomeric fraction, defined as (+) enantiomer/(sum of the (+) and (-) enantiomers), where a racemic composition has EF = 0.5. Racemic alpha-hexachlorocyclohexane (alpha-HCH) was measured in Asian air masses at Okinawa and in Chinese and South Korean soils. Nonracemic alpha-HCH (EF = 0.528 +/- 0.0048) was measured in regional air masses at CPO, and may reflect volatilization from the Pacific Ocean and regional soils. However, during trans-Pacific transport events at CPO, the alpha-HCH EFs were significantly more racemic (EF = 0.513 +/- 0.0003, p < 0.001). Racemic alpha-HCH was consistently measured at MPO and MBO in trans-Pacific air masses that had spent considerable time in the free troposphere. The alpha-HCH EFs in CPO, MPO, and MBO air masses were negatively correlated (p = 0.0017) with the amount of time the air mass spent above the boundary layer, along the 10-day back air mass trajectory, prior to being sampled. This suggests that, on the West coast of the U.S., the alpha-HCH in the free troposphere is racemic. Racemic signatures of cis- and trans-chlordane were measured in air masses at all four air sampling sites, suggesting that Asian and U.S. urban areas continue to be sources of chlordane that has not yet been biotransformed. PMID:19475954

  12. Enantiomeric Signatures of Organochlorine Pesticides in Asian, Trans-Pacific and Western U.S. Air Masses

    PubMed Central

    Genualdi, Susan A.; Massey Simonich, Staci L.; Primbs, Toby K.; Bidleman, Terry F.; Jantunen, Liisa M.; Ryoo, Keon-Sang; Zhu, Tong

    2009-01-01

    The enantiomeric signatures of organochlorine pesticides were measured in air masses from Okinawa, Japan and three remote locations in the Pacific Northwestern U.S.: Cheeka Peak Observatory (CPO), a marine boundary layer site on the Olympic Peninsula of Washington at 500 meters above sea level (m.a.s.l); Mary’s Peak Observatory (MPO), a site at 1250 m.a.s.l in Oregon’s Coast range; and Mt. Bachelor Observatory (MBO), a site at 2763 m.a.s.l in Oregon’s Cascade range. The enantiomeric signatures of composite soil samples, collected from China, South Korea, and the western U.S. were also measured. The data from chiral analysis was expressed as the enantiomeric fraction (1), defined as (+) enantiomer/(sum of the (+) and (−) enantiomers), where a racemic composition has EF = 0.5. Racemic α-hexachlorocyclohexane (α-HCH) was measured in Asian air masses at Okinawa and in Chinese and South Korean soils. Non-racemic α-HCH (EF = 0.528 ± 0.0048) was measured in regional air masses at CPO, and may reflect volatilization from the Pacific Ocean and regional soils. However, during trans-Pacific transport events at CPO, the α-HCH EFs were significantly more racemic (EF = 0.513 ± 0.0003, p < 0.001). Racemic α-HCH was consistently measured at MPO and MBO in trans-Pacific air masses that had spent considerable time in the free troposphere. The α-HCH EFs in CPO, MPO, and MBO air masses were negatively correlated (p = 0.0017) with the amount of time the air mass spent above the boundary layer, along the 10-day back air mass trajectory, prior to being sampled. This suggests that, on the West coast of the U.S., the α-HCH in the free troposphere is racemic. Racemic signatures of cis- and trans-chlordane were measured in air masses at all four air sampling sites, suggesting that Asian and U.S. urban areas continue to be sources of chlordane that has not yet been biotransformed. PMID:19475954

  13. Enantiomeric signatures of organochlorine pesticides in Asian, trans-Pacific, and western U.S. air masses.

    PubMed

    Genualdi, Susan A; Simonich, Staci L Massey; Primbs, Toby K; Bidleman, Terry F; Jantunen, Liisa M; Ryoo, Keon-Sang; Zhu, Tong

    2009-04-15

    The enantiomeric signatures of organochlorine pesticides were measured in air masses from Okinawa, Japan and three remote locations in the Pacific Northwestern United States: Cheeka Peak Observatory (CPO), a marine boundary layer site on the Olympic Peninsula of Washington at 500 m above sea level (m.a.s.l); Mary's Peak Observatory (MPO), a site at 1250 m.a.s.l in Oregon's Coast range; and Mt. Bachelor Observatory (MBO), a site at 2763 m.a.s.l in Oregon's Cascade range. The enantiomeric signatures of composite soil samples, collected from China, South Korea, and the western U.S. were also measured. The data from chiral analysis was expressed asthe enantiomeric fraction, defined as (+) enantiomer/(sum of the (+) and (-) enantiomers), where a racemic composition has EF = 0.5. Racemic alpha-hexachlorocyclohexane (alpha-HCH) was measured in Asian air masses at Okinawa and in Chinese and South Korean soils. Nonracemic alpha-HCH (EF = 0.528 +/- 0.0048) was measured in regional air masses at CPO, and may reflect volatilization from the Pacific Ocean and regional soils. However, during trans-Pacific transport events at CPO, the alpha-HCH EFs were significantly more racemic (EF = 0.513 +/- 0.0003, p < 0.001). Racemic alpha-HCH was consistently measured at MPO and MBO in trans-Pacific air masses that had spent considerable time in the free troposphere. The alpha-HCH EFs in CPO, MPO, and MBO air masses were negatively correlated (p = 0.0017) with the amount of time the air mass spent above the boundary layer, along the 10-day back air mass trajectory, prior to being sampled. This suggests that, on the West coast of the U.S., the alpha-HCH in the free troposphere is racemic. Racemic signatures of cis- and trans-chlordane were measured in air masses at all four air sampling sites, suggesting that Asian and U.S. urban areas continue to be sources of chlordane that has not yet been biotransformed.

  14. Role of circulation scales and water mass distributions on larval fish habitats in the Eastern Tropical Pacific off Mexico

    NASA Astrophysics Data System (ADS)

    León-Chávez, Cristina A.; Beier, Emilio; Sánchez-Velasco, Laura; Barton, Eric Desmond; Godínez, Victor M.

    2015-06-01

    On the basis of five oceanographic cruises carried out in the Eastern Tropical Pacific off Mexico, relationships between the larval fish habitats (areas inhabited by larval fish assemblages) and the environmental circulation scales (mesoscale, seasonal, and interannual) were examined. Analysis of in situ data over a grid of hydrographic stations and oblique zooplankton hauls with bongo net (505 µm) was combined with orthogonal robust functions decomposition applied to altimetry anomalies obtained from satellite. During both cool (March and June) and warm (August and November) periods, Bray-Curtis dissimilarity Index defined three recurrent larval fish habitats which varied in species composition and extent as a function of the environmental scales. The variability of the Tropical larval fish habitat (characterized by high species richness, and dominated by Vinciguerria lucetia, Diogenichthys laternatus, and Diaphus pacificus) was associated with the seasonal changes. The Transitional-California Current larval fish habitat (dominated by V. lucetia and D. laternatus, with lower mean abundance and lower species richness than in the Tropical habitat) and Coastal-and-Upwelling larval fish habitat (dominated by Bregmaceros bathymaster) was associated mainly with mesoscale activity induced by eddies and with coastal upwelling. During February 2010, the Tropical larval fish habitat predominated offshore and the Transitional-California Current larval fish habitat was not present, which we attribute to the effect of El Niño conditions. Thus, the mesoscale, seasonal, and interannual environmental scales affect the composition and extension of larval fish habitats.

  15. Body mass penalties in the physical fitness tests of the Army, Air Force, and Navy.

    PubMed

    Vanderburgh, Paul M; Crowder, Todd A

    2006-08-01

    Recent research has empirically documented a consistent penalty against heavier service members for events identical or similar to those in the physical fitness tests of the Army, Air Force, and Navy. These penalties, which are not related to body fatness, are based on biological scaling models and have a physiological basis. Using hypothetical cases, we quantified the penalties for men, with body mass of 60 vs. 90 kg, and women, 45 vs. 75 kg, to be 15% to 20% for the fitness tests of these three services. Such penalties alone can adversely affect awards and promotions for heavier service members. To deal equitably with these penalties in a practical manner, we offer two recommendations, i.e., (1) implementation of revised fitness tests with balanced events, in which the penalties of one event for heavier service members are balanced by an equal and opposite bias against lighter service members, or (2) development of correction factors that can be multiplied by raw scores to yield adjusted scores free of body mass bias.

  16. Statistical downscaling of general-circulation-model- simulated average monthly air temperature to the beginning of flowering of the dandelion (Taraxacum officinale) in Slovenia

    NASA Astrophysics Data System (ADS)

    Bergant, Klemen; Kajfež-Bogataj, Lučka; Črepinšek, Zalika

    2002-02-01

    Phenological observations are a valuable source of information for investigating the relationship between climate variation and plant development. Potential climate change in the future will shift the occurrence of phenological phases. Information about future climate conditions is needed in order to estimate this shift. General circulation models (GCM) provide the best information about future climate change. They are able to simulate reliably the most important mean features on a large scale, but they fail on a regional scale because of their low spatial resolution. A common approach to bridging the scale gap is statistical downscaling, which was used to relate the beginning of flowering of Taraxacum officinale in Slovenia with the monthly mean near-surface air temperature for January, February and March in Central Europe. Statistical models were developed and tested with NCAR/NCEP Reanalysis predictor data and EARS predictand data for the period 1960-1999. Prior to developing statistical models, empirical orthogonal function (EOF) analysis was employed on the predictor data. Multiple linear regression was used to relate the beginning of flowering with expansion coefficients of the first three EOF for the Janauary, Febrauary and March air temperatures, and a strong correlation was found between them. Developed statistical models were employed on the results of two GCM (HadCM3 and ECHAM4/OPYC3) to estimate the potential shifts in the beginning of flowering for the periods 1990-2019 and 2020-2049 in comparison with the period 1960-1989. The HadCM3 model predicts, on average, 4 days earlier occurrence and ECHAM4/OPYC3 5 days earlier occurrence of flowering in the period 1990-2019. The analogous results for the period 2020-2049 are a 10- and 11-day earlier occurrence.

  17. Air-sea fluxes and satellite-based estimation of water masses formation

    NASA Astrophysics Data System (ADS)

    Sabia, Roberto; Klockmann, Marlene; Fernandez-Prieto, Diego; Donlon, Craig

    2015-04-01

    Recent work linking satellite-based measurements of sea surface salinity (SSS) and sea surface temperature (SST) with traditional physical oceanography has demonstrated the capability of generating routinely satellite-derived surface T-S diagrams [1] and analyze the distribution/dynamics of SSS and its relative surface density with respect to in-situ measurements. Even more recently [2,3], this framework has been extended by exploiting these T-S diagrams as a diagnostic tool to derive water masses formation rates and areas. A water mass describes a water body with physical properties distinct from the surrounding water, formed at the ocean surface under specific conditions which determine its temperature and salinity. The SST and SSS (and thus also density) at the ocean surface are largely determined by fluxes of heat and freshwater. The surface density flux is a function of the latter two and describes the change of the density of seawater at the surface. To obtain observations of water mass formation is of great interest, since they serve as indirect observations of the thermo-haline circulation. The SSS data which has become available through the SMOS [4] and Aquarius [5] satellite missions will provide the possibility of studying also the effect of temporally-varying SSS fields on water mass formation. In the present study, the formation of water masses as a function of SST and SSS is derived from the surface density flux by integrating the latter over a specific area and time period in bins of SST and SSS and then taking the derivative of the total density flux with respect to density. This study presents a test case using SMOS SSS, OSTIA SST, as well as Argo ISAS SST and SSS for comparison, heat fluxes from the NOCS Surface Flux Data Set v2.0, OAFlux evaporation and CMORPH precipitation. The study area, initially referred to the North Atlantic, is extended over two additional ocean basins and the study period covers the 2011-2012 timeframe. Yearly, seasonal

  18. Characteristics of tyre dust in polluted air: Studies by single particle mass spectrometry (ATOFMS)

    NASA Astrophysics Data System (ADS)

    Dall'Osto, Manuel; Beddows, David C. S.; Gietl, Johanna K.; Olatunbosun, Oluremi A.; Yang, Xiaoguang; Harrison, Roy M.

    2014-09-01

    There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35 nm and 85 nm were obtained from SMPS/APS measurements over the range 6-20,000 nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000 nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z > 100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.

  19. Study Case of Air-Mass Modification over Poland and Romania Observed by the Means of Multiwavelength Raman Depolarization Lidars

    NASA Astrophysics Data System (ADS)

    Costa-Surós, Montserrat; Janicka, Lucja; Stachlewska, Iwona S.; Nemuc, Anca; Talianu, Camelia; Heese, Birgit; Engelmann, Ronny

    2016-06-01

    An air-mass modification, on its way from Poland to Romania, observed between 19-21 July 2014 is discussed. The air-mass was investigated using data of two multi-wavelength lidars capable of performing regular elastic, depolarization and Raman measurements in Warsaw, Poland, and in Magurele, Romania. The analysis was focused on evaluating optical properties of aerosol in order to search for similarities and differences in the vertical profiles describing the atmospheric layers above the two stations within given period.

  20. AIR COOLED NEUTRONIC REACTOR

    DOEpatents

    Fermi, E.; Szilard, L.

    1958-05-27

    A nuclear reactor of the air-cooled, graphite moderated type is described. The active core consists of a cubicle mass of graphite, approximately 25 feet in each dimension, having horizontal channels of square cross section extending between two of the opposite faces, a plurality of cylindrical uranium slugs disposed in end to end abutting relationship within said channels providing a space in the channels through which air may be circulated, and a cadmium control rod extending within a channel provided in the moderator. Suitable shielding is provlded around the core, as are also provided a fuel element loading and discharge means, and a means to circulate air through the coolant channels through the fuel charels to cool the reactor.

  1. Salinity minima, water masses and surface circulation in the Eastern Tropical Pacific off Mexico and surrounding areas

    NASA Astrophysics Data System (ADS)

    Portela, Esther; Beier, Emilio; Godínez, Victor; Castro, Rubén; Desmond Barton, Eric

    2016-04-01

    The seasonal variations of the water masses and their interactions are analyzed in the Tropical Pacific off Mexico (TPOM) and four contiguous areas of on the basis of new extensive hydrographic database. The regional water masses intervals are redefined in terms of Absolute Salinity (SA) in g kg-1 and Conservative Temperature (Θ) according to TEOS - 10. The California Current System Water (CCSW) mass is introduced as an improved description of the former California Current Water (CCW) together with the Subarctic Water (SAW) to describe better the characteristics of the components of the California Current System. Hydrographic data, Precipitation-Evaporation balance and geostrophic currents were used to investigate the origin and seasonality of two salinity minima in the area. The shallow salinity minimum of around 33.5 g kg-1 originated in the California Current System and became saltier but less dense water as it traveled to the southeast. It can be identified as a mixture of CCSW and tropical waters. The surface salinity minimum of 32 - 33 g kg-1 was seen as a sharp surface feature in the TPOM from August to November. It was produced by the arrival of tropical waters from the south in combination with the net precipitation in the area during these months. This result provides new evidence of the presence of the poleward-flowing Mexican Coastal Current and, for the first time, of its seasonal pattern of variation.

  2. Detrital sources and water mass circulation in the tropical North Atlantic during the Late Cretaceous to Paleogene

    NASA Astrophysics Data System (ADS)

    Martin, E. E.; Pugh, E.; Kamenov, G. D.; MacLeod, K. G.

    2014-12-01

    Seawater Nd isotopes from fossil fish teeth in Campanian to Paleogene calcareous claystone on Demerara Rise in the tropical North Atlantic record a change from epsilon Nd values of -17 to -11 during the late Maastrichtian. This shift has been identified in three different Ocean Drilling Program (ODP) sites that span from 600 to 1500 m paleodepths (ODP sites 1259, 1260 and 1261) and has been interpreted as a transition from a warm saline intermediate water mass formed on the South American margin, referred to as Demerara Bottom Water, to a source from the North Atlantic. A study of corresponding detrital Sr, Nd and Pb isotopes was undertaken to confirm the isotopic values derived from fish teeth record water mass compositions rather than diagenesis or boundary exchange. Several leaching procedures designed to remove Fe-Mn oxide coatings and the seawater signature they carry from the detrital fractions were tested. Sr isotopic data indicate a 0.02 M hydroxylamine hydrochloride (HH) leach was ineffective at removing the Fe-Mn oxides whereas a 1.0 M HH leach produced detrital Sr isotopic values that were consistent for all three sites and plotted farther from the seawater value. Detrital isotopic results can be divided into three intervals: 1) 73 - 66 Ma, when DBW is present, 2) 66 - 61 Ma, during the transition to North Atlantic sources, and 3) <61 Ma, when North Atlantic sources appear to dominate. During interval 1, detrital Nd isotopes increase gradually, while Sr and Pb isotopic ratios are relatively constant. Leading into interval 2, detrital Nd isotopes are fairly constant while there is a stepwise increase in Sr and Pb isotopes. Leading into interval 3, there is a large increase in Nd and decrease in Sr isotopes and a slight decrease in Pb isotopes. The subtle differences in the timing of changes in fish teeth and detrital Nd isotopes suggest the seawater signal is responding to changes in water mass rather than changes in sediment composition (boundary

  3. A Wind Tunnel Model to Explore Unsteady Circulation Control for General Aviation Applications

    NASA Technical Reports Server (NTRS)

    Cagle, Christopher M.; Jones, Gregory S.

    2002-01-01

    Circulation Control airfoils have been demonstrated to provide substantial improvements in lift over conventional airfoils. The General Aviation Circular Control model is an attempt to address some of the concerns of this technique. The primary focus is to substantially reduce the amount of air mass flow by implementing unsteady flow. This paper describes a wind tunnel model that implements unsteady circulation control by pulsing internal pneumatic valves and details some preliminary results from the first test entry.

  4. Anaerobic degradation of purified terephthalic acid wastewater using a novel, rapid mass-transfer circulating fluidized bed.

    PubMed

    Feng, Yangyang; Lu, Beibei; Jiang, Yu; Chen, Yinwen; Shen, Shubao

    2012-01-01

    The anaerobic treatability of purified terephthalic acid (PTA) wastewater in a novel, rapid mass-transfer fluidized bed reactor using brick particles as porous carrier materials was investigated. The reactor operation was stable after a short 34 day start-up period, with chemical oxygen demand (COD) removal efficiency between 65 and 75%, terephthalate (TA) removal efficiency between 60% and 70%, and system organic loading rate (OLR) increasing from 7.37 to 18.52 kg COD/m(3) d. The results demonstrate that the reactor is very efficient, and requires a low hydraulic retention time (HRT) of 8 h to remove both TA and COD from the high-concentration PTA wastewater. The system also has high resistance capacity to varied OLR.

  5. On the association between daily mortality and air mass types in Athens, Greece during winter and summer

    NASA Astrophysics Data System (ADS)

    Kassomenos, Pavlos A.; Gryparis, Alexandros; Katsouyanni, Klea

    2007-03-01

    In this study, we examined the short-term effects of air mass types on mortality in Athens, Greece. An objective air mass types classification was used, based on meteorological parameters measured at the surface. Mortality data were treated with generalized additive models (GAM) and extending Poisson regression, using a LOESS smoother to control for the confounding effects of seasonal patterns, adjusting also for temperature, long-term trends, day of the week, and ambient particle concentrations. The introduced air mass classification explains the daily variation of mortality to a statistically significant degree. The highest daily mortality was observed on days characterized by southerly flow conditions for both the cold (increase in relative risk for mortality 9%; with a 95% confidence interval: 3-14%), and the warm period (7%; with a 95% confidence interval: 2-13%) of the year. The northeasterly flow is associated with the lowest mortality. Effects on mortality, independent of temperature, are observed mainly for lag 0 during the cold period, but persist longer during the warm period. Not adjusting for temperature and/or ambient particle levels slightly alters the results, which then reflect the known temperature and particle effects, already reported in the literature. In conclusion, we find that air mass types have independent effects on mortality for both the cold and warm season and may be used to predict weather-related adverse health effects.

  6. Dietary Magnesium Is Positively Associated With Skeletal Muscle Power and Indices of Muscle Mass and May Attenuate the Association Between Circulating C-Reactive Protein and Muscle Mass in Women.

    PubMed

    Welch, Ailsa A; Kelaiditi, Eirini; Jennings, Amy; Steves, Claire J; Spector, Tim D; MacGregor, Alexander

    2016-02-01

    Age-related loss of skeletal muscle mass and strength are risk factors for sarcopenia, osteoporosis, falls, fractures, frailty, and mortality. Dietary magnesium (Mg) could play a role in prevention of age-related loss of skeletal muscle mass, power, and strength directly through physiological mechanisms or indirectly through an impact on chronic low-grade inflammation, itself a risk factor for loss of skeletal muscle mass and strength. In a cross-sectional study of 2570 women aged 18 to 79 years, we examined associations between intakes of Mg, estimated using a food-frequency questionnaire (FFQ), dual-energy X-ray absorptiometry (DXA)-derived measures of muscle mass (fat-free mass as a percentage of body weight [FFM%], fat-free mass index [FFMI, kg/m(2)]), leg explosive power (LEP), and grip strength (n = 949 only). We also examined associations between circulating hs-CRP (C-reactive protein) and muscle mass and LEP, and explored the potential attenuation of these relationships by Mg. We compared our findings with those of age and protein intake. Endpoints were calculated by quintile of Mg and adjusted for relevant confounders. Significant positive associations were found between a higher Mg and indices of skeletal muscle mass and LEP, and also with hs-CRP, after adjustment for covariates. Contrasting extreme quintiles of Mg intake showed differences of 2.6% for FFM% (p trend < 0.001), 0.4 kg/m(2) for FFMI (p trend = 0.005), and 19.6 watts/kg for LEP (p trend < 0.001). Compared with protein, these positive associations were 7 times greater for FFM% and 2.5 times greater for LEP. We also found that higher hs-CRP was negatively associated with skeletal muscle mass and, in statistical modeling, that a higher dietary Mg attenuated this negative relationship by 6.5%, with greater attenuation in women older than 50 years. No association was found between Mg and grip strength. Our results suggest that dietary magnesium may aid conservation of age-related loss of skeletal

  7. Caucasian children's fat mass: routine anthropometry v. air-displacement plethysmography.

    PubMed

    Michels, Nathalie; Huybrechts, Inge; Bammann, Karin; Lissner, Lauren; Moreno, Luis; Peeters, Maarten; Sioen, Isabelle; Vanaelst, Barbara; Vyncke, Krishna; De Henauw, Stefaan

    2013-04-28

    The present paper will use fat mass percentage (FM%) obtained via BOD POD® air-displacement plethysmography (FMADP%) to examine the relative validity of (1) anthropometric measurements/indices and (2) of FM% assessed with equations (FMeq%) based on skinfold thickness and bioelectrical impedance (BIA). In 480 Belgian children (aged 5-11 years) weight, height, skinfold thickness (triceps and subscapular), body circumferences (mid-upper arm, waist and hip), foot-to-foot BIA (Tanita®) and FMADP% were measured. Anthropometric measurements and calculated indices were compared with FMADP%. Next, published equations were used to calculate FMeq% using impedance (equations of Tanita®, Tyrrell, Shaefer and Deurenberg) or skinfold thickness (equations of Slaughter, Goran, Dezenberg and Deurenberg). Both indices and equations performed better in girls than in boys. For both sexes, the sum of skinfold thicknesses resulted in the highest correlation with FMADP%, followed by triceps skinfold, arm fat area and subscapular skinfold. In general, comparing FMeq% with FMADP% indicated mostly an age and sex effect, and an increasing underestimation but less dispersion with increasing FM%. The Tanita® impedance equation and the Deurenberg skinfold equation performed the best, although none of the used equations were interchangeable with FMADP%. In conclusion, the sum of triceps and subscapular skinfold thickness is recommended as marker of FM% in the absence of specialised technologies. Nevertheless, the higher workload, cost and survey management of an immobile device like the BOD POD® remains justified.

  8. Background NO/sub x/ mixing ratios in air masses over the North Atlantic ocean

    SciTech Connect

    Helas, G.; Warneck, P.

    1981-08-20

    A chemiluminescence analyzer was used to measure NO/sub x/ mixing ratios at the west coast of Ireland. Two measurement modes allowed the determination of NO and NO/sub x/ = NO+NO/sub 2/. In a third mode using a molybdenum converter, higher signals were observed than was in the second mode indicating that nitrogen compounds other than NO+NO/sub 2/ are registered. They are denoted 'excess NO/sub x/'. The average NO/sub 2/ mixing ratio for a week period was 101 +- 87 pptv. In pure marine air masses identified by means of trajectory calculations, the NO/sub 2/ mixing ratios were lower and exhibited in addition a diurnal variation with nighttime values of 37 +- 6 pptv and average values of 87 +- 47 pptv. Possible origins of the diurnal variation are discussed. For such conditions, the NO mixing ratio generally was unmeasurably small, certainly less than 10 pptv. The excess NO/sub x/ is also higher during the day compared with nighttime values of about 70 pptv. Further studies are required to identify the compounds involved.

  9. New Directions: Questions surrounding suspended particle mass used as a surrogate for air quality and for regulatory control of ambient urban air pollution

    NASA Astrophysics Data System (ADS)

    Hoare, John L.

    2014-07-01

    The original choice of particulate matter mass (PM) as a realistic surrogate for gross air pollution has gradually evolved into routine use nowadays of epidemiologically-based estimates of the monetary and other benefits expected from regulating urban air quality. Unfortunately, the statistical associations facilitating such calculations usually are based on single indices of air pollution whereas the health effects themselves are more broadly based causally. For this and other reasons the economic benefits of control tend to be exaggerated. Primarily because of their assumed inherently inferior respirability, particles ≥10 μm are generally excluded from such considerations. Where the particles themselves are chemically heterogeneous, as in an urban context, this may be inappropriate. Clearly all air-borne particles, whether coarse or fine, are susceptible to inhalation. Hence, the possibility exists for any adhering potentially harmful semi-volatile substances to be subsequently de-sorbed in vivo thereby facilitating their transport deeper into the lungs. Consequently, this alone may be a sufficient reason for including rather than rejecting during air quality monitoring the relatively coarse 10-100 μm particle fraction, ideally in conjunction with routine estimation of the gaseous co-pollutants thereby facilitating a multi-pollutant approach apropos regulation.

  10. A new application of a finite element heat and mass transfer numerical modeling code (FEHM) to heat and fluid circulation in lava domes

    NASA Astrophysics Data System (ADS)

    Ball, J. L.; Stauffer, P. H.; Calder, E. S.

    2012-12-01

    Lava domes have been well-characterized in terms of their surface structure and activity, but there is much to be learned about their internal structure and geothermal systems. Even when a lava dome is no longer actively erupting, subsurface studies are often difficult to conduct; lava domes are highly complex structures, but their rugged nature often precludes systematic drilling and/or geophysical surveys. Because of this, we know little about the internal geothermal activity that may still contribute to both hazards and opportunities for exploitation of mineral deposits and hot groundwater. Despite the difficulty of studying the interior of lava domes directly, numerical modeling can still provide insights into the behavior of their geothermal systems. Lava domes have the potential to be highly transmissive structures, and the presence of hot springs in the vicinity of lava domes (Santiaguito in Guatemala, La Soufriere on Guadeloupe) suggests that water circulation may be an important process in post-eruptive dome evolution. FEHM, a heat and mass transfer modeling code developed at Los Alamos National Laboratory (fehm.lanl.gov) is an ideal tool to study fluid and gas circulation in geologic structures. FEHM was developed for subsurface reservoir modeling (originally for the Hot Dry Rock geothermal project) and is capable of dealing with both high- (magmatic) and low-temperature fluids. In this study, FEHM has been used in combination with a LANL-developed grid-generating utility (LaGriT) to create an idealized model of water circulation in a saturated lava dome. Multiple material regions are used to represent the dome core, outer talus layer, conduit, and volcanic substrate. Material properties (such as permeability, porosity, density, etc.) were chosen from a combination of literature review and sensitivity testing using a simplified dome geometry and a continuum modeling approach that accounts for fractures (Equivalent Porous Medium) was used when applying

  11. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    NASA Astrophysics Data System (ADS)

    Hoseeinzadeh, Sepideh; Gorji-Bandpy, Mofid

    2012-04-01

    This paper presents a computational fluid dynamics (CFD) calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  12. Sample Preparation and Liquid Chromatography-Tandem Mass Spectrometry for Multiple Steroids in Mammalian and Avian Circulation

    PubMed Central

    Soma, Kiran K.; Wynne-Edwards, Katherine E.

    2012-01-01

    Blood samples from wild mammals and birds are often limited in volume, allowing researchers to quantify only one or two steroids from a single sample by immunoassays. In addition, wildlife serum or plasma samples are often lipemic, necessitating stringent sample preparation. Here, we validated sample preparation for simultaneous liquid chromatography – tandem mass spectrometry (LC-MS/MS) quantitation of cortisol, corticosterone, 11-deoxycortisol, dehydroepiandrosterone (DHEA), 17β-estradiol, progesterone, 17α-hydroxyprogesterone and testosterone from diverse mammalian (7 species) and avian (5 species) samples. Using 100 µL of serum or plasma, we quantified (signal-to-noise (S/N) ratio ≥10) 4–7 steroids depending on the species and sample, without derivatization. Steroids were extracted from serum or plasma using automated solid-phase extraction where samples were loaded onto C18 columns, washed with water and hexane, and then eluted with ethyl acetate. Quantitation by LC-MS/MS was done in positive ion, multiple reaction-monitoring (MRM) mode with an atmospheric pressure chemical ionization (APCI) source and heated nebulizer (500°C). Deuterated steroids served as internal standards and run time was 15 minutes. Extraction recoveries were 87–101% for the 8 analytes, and all intra- and inter-run CVs were ≤8.25%. This quantitation method yields good recoveries with variable lipid-content samples, avoids antibody cross-reactivity issues, and delivers results for multiple steroids. Thus, this method can enrich datasets by providing simultaneous quantitation of multiple steroids, and allow researchers to reimagine the hypotheses that could be tested with their volume-limited, lipemic, wildlife samples. PMID:22384262

  13. Mountains and Tropical Circulation

    NASA Astrophysics Data System (ADS)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  14. Lung Circulation.

    PubMed

    Suresh, Karthik; Shimoda, Larissa A

    2016-04-01

    The circulation of the lung is unique both in volume and function. For example, it is the only organ with two circulations: the pulmonary circulation, the main function of which is gas exchange, and the bronchial circulation, a systemic vascular supply that provides oxygenated blood to the walls of the conducting airways, pulmonary arteries and veins. The pulmonary circulation accommodates the entire cardiac output, maintaining high blood flow at low intravascular arterial pressure. As compared with the systemic circulation, pulmonary arteries have thinner walls with much less vascular smooth muscle and a relative lack of basal tone. Factors controlling pulmonary blood flow include vascular structure, gravity, mechanical effects of breathing, and the influence of neural and humoral factors. Pulmonary vascular tone is also altered by hypoxia, which causes pulmonary vasoconstriction. If the hypoxic stimulus persists for a prolonged period, contraction is accompanied by remodeling of the vasculature, resulting in pulmonary hypertension. In addition, genetic and environmental factors can also confer susceptibility to development of pulmonary hypertension. Under normal conditions, the endothelium forms a tight barrier, actively regulating interstitial fluid homeostasis. Infection and inflammation compromise normal barrier homeostasis, resulting in increased permeability and edema formation. This article focuses on reviewing the basics of the lung circulation (pulmonary and bronchial), normal development and transition at birth and vasoregulation. Mechanisms contributing to pathological conditions in the pulmonary circulation, in particular when barrier function is disrupted and during development of pulmonary hypertension, will also be discussed. PMID:27065170

  15. Chiral Signatures of Anthropogenic Semi-Volatile Organic Compounds in Asian, trans- Pacific, and Pacific Northwestern Air Masses

    NASA Astrophysics Data System (ADS)

    Genualdi, S.; Primbs, T.; Bidleman, T.; Jantunen, L.; Simonich, S.

    2006-12-01

    The goal of this research is to use the chiral signatures of Semi-Volatile Organic Compounds (SOCs) to distinguish between new and old sources in Asian, trans-Pacific, and regional air masses. During 2004, a six week air sampling campaign was conducted at a remote site in Okinawa, Japan to determine the chemical composition of Eurasian air masses. During 2003 and 2004, high volume air samples were collected at three different locations in the Pacific Northwest of the United States. These sampling locations were; Mary's Peak Observatory (MPO) located at 1250m in the Oregon Coast Range, Mt. Bachelor located at 2800m in Oregon's Cascade Range, and Cheeka Peak Observatory (CPO) located at 500m in the state of Washington. The air samples consisted of both polyurethane foam and XAD-2 resin to collect the gas phase SOCs, and glass fiber filters to collect the particulate phase SOCs. The samples were extracted using accelerated solvent extraction and enantiomer fractions were determined using GCMS-ECNI with the use of a BGB Analytik chiral column. The chiral SOCs, á-Hexachlorocyclohexane, cis and trans chlordane, heptachlor epoxide, and o'p' DDT, were measured, the enantiomer ratios were determined, and potential new and historical sources of these compounds were identified.

  16. Ozone-surface interactions: Investigations of mechanisms, kinetics, mass transport, and implications for indoor air quality

    SciTech Connect

    Morrison, Glenn C.

    1999-12-01

    {sup {minus}7}, 10{sup {minus}5}, and 10{sup {minus}5} respectively. To understand how internal surface area influences the equivalent reaction probability of whole carpet, a model of ozone diffusion into and reaction with internal carpet components was developed. This was then used to predict apparent reaction probabilities for carpet. He combines this with a modified model of turbulent mass transfer developed by Liu, et al. to predict deposition rates and indoor ozone concentrations. The model predicts that carpet should have an equivalent reaction probability of about 10{sup {minus}5}, matching laboratory measurements of the reaction probability. For both carpet and duct materials, surfaces become progressively quenched (aging), losing the ability to react or otherwise take up ozone. He evaluated the functional form of aging and find that the reaction probability follows a power function with respect to the cumulative uptake of ozone. To understand ozone aging of surfaces, he developed several mathematical descriptions of aging based on two different mechanisms. The observed functional form of aging is mimicked by a model which describes ozone diffusion with internal reaction in a solid. He shows that the fleecy nature of carpet materials in combination with the model of ozone diffusion below a fiber surface and internal reaction may explain the functional form and the magnitude of power function parameters observed due to ozone interactions with carpet. The ozone induced aldehyde emissions, measured from duct materials, were combined with an indoor air quality model to show that concentrations of aldehydes indoors may approach odorous levels. He shows that ducts are unlikely to be a significant sink for ozone due to the low reaction probability in combination with the short residence time of air in ducts.

  17. Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008)

    NASA Astrophysics Data System (ADS)

    Crumeyrolle, S.; Schwarzenboeck, A.; Roger, J. C.; Sellegri, K.; Burkhart, J. F.; Stohl, A.; Gomes, L.; Quennehen, B.; Roberts, G.; Weigel, R.; Villani, P.; Pichon, J. M.; Bourrianne, T.; Laj, P.

    2013-05-01

    Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project, the Météo-France aircraft ATR-42 performed 22 research flights over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped to study the aerosol physical, chemical, hygroscopic and optical properties, as well as cloud microphysics. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin, allowing for a qualitative evaluation of emission influence on the respective air parcel. This study shows that the extensive aerosol parameters (aerosol mass and number concentrations) show vertical decreasing gradients and in some air masses maximum mass concentrations (mainly organics) in an intermediate layer (1-3 km). The observed mass concentrations (in the boundary layer (BL): between 10 and 30 μg m-3; lower free troposphere (LFT): 0.8 and 14 μg m-3) are high especially in comparison with the 2015 European norms for PM2.5 (25 μg m-3) and with previous airborne studies performed over England (Morgan et al., 2009; McMeeking et al., 2012). Particle number size distributions show a larger fraction of particles in the accumulation size range in the LFT compared to BL. The chemical composition of submicron aerosol particles is dominated by organics in the BL, while ammonium sulphate dominates the submicron aerosols in the LFT, especially in the aerosol particles originated from north-eastern Europe (~ 80%), also experiencing nucleation events along the transport. As a consequence, first the particle CCN acting ability, shown by the CCN/CN ratio, and second the average values of the scattering cross sections of optically active particles (i.e. scattering coefficient divided by the optical active particle concentration) are increased in the LFT compared to BL.

  18. Influence of the ozone profile above Madrid (Spain) on Brewer estimation of ozone air mass factor

    NASA Astrophysics Data System (ADS)

    Antón, M.; López, M.; Costa, M. J.; Serrano, A.; Bortoli, D.; Bañón, M.; Vilaplana, J. M.; Silva, A. M.

    2009-08-01

    The methodology used by Brewer spectroradiometers to estimate the ozone column is based on differential absorption spectroscopy. This methodology employs the ozone air mass factor (AMF) to derive the total ozone column from the slant path ozone amount. For the calculating the ozone AMF, the Brewer algorithm assumes that the ozone layer is located at a fixed height of 22 km. However, for a real specific site the ozone presents a certain profile, which varies spatially and temporally depending on the latitude, altitude and dynamical conditions of the atmosphere above the site of measurements. In this sense, this work address the reliability of the mentioned assumption and analyses the influence of the ozone profiles measured above Madrid (Spain) in the ozone AMF calculations. The approximated ozone AMF used by the Brewer algorithm is compared with simulations obtained using the libRadtran radiative transfer model code. The results show an excellent agreement between the simulated and the approximated AMF values for solar zenith angle lower than 75°. In addition, the relative differences remain lower than 2% at 85°. These good results are mainly due to the fact that the altitude of the ozone layer assumed constant by the Brewer algorithm for all latitudes notably can be considered representative of the real profile of ozone above Madrid (average value of 21.7±1.8 km). The operational ozone AMF calculations for Brewer instruments are limited, in general, to SZA below 80°. Extending the usable SZA range is especially relevant for Brewer instruments located at high mid-latitudes.

  19. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    SciTech Connect

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  20. Influence of runoff, high frequency atmospheric forcing and model resolution on deep water mass formation regions and Atlantic Meridional Overturning Circulation, from a numerical model.

    NASA Astrophysics Data System (ADS)

    Garcia Quintana, Yarisbel; Courtois, Peggy; Hu, Xianmin; Pennelly, Clark; Myers, Paul G.

    2016-04-01

    Water mass formation regions act as windows to the deep ocean where surface waters are transformed to intermediate and deep waters. Within the North Atlantic, Labrador Sea Water (LSW) is convectively produced in the Labrador Sea while in the Nordic Seas the source waters for Denmark Strait Overflow Water (DSOW) and Iceland-Scotland Overflow Water (NEADW) are formed. They are the main components of the North Atlantic Deep Water (NADW) which forms the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). We explore the changes of the LSW formation rates and in AMOC strength as consequence of runoff glacial melt, high frequency atmospheric forcing influence and variations in model's resolution. We use 1/4° resolution Arctic and Northern Hemisphere Atlantic (ANHA4) configuration from the Nucleus for European Modelling of the Ocean (NEMO) model. A nest using ANHA4 and the Adaptive Grid Refinement in FORTRAN (AGRIF) package was used to increase the resolution to 1/12° in the sub-polar gyre. The formation rate is calculated based upon a kinematic subduction approach where the exchange through the dynamic mixed layer base is calculated based on shallowing and deepening in the mixed layer, and convergence of horizontal transport into or out of the mixed layer. Lastly we use a Lagrangian tool (Ariane) to track the path of the DSOW and the NEADW from their formation source.

  1. Determination of benzene, toluene, ethylbenzene and xylenes in air by solid phase micro-extraction/gas chromatography/mass spectrometry.

    PubMed

    Tumbiolo, Simonetta; Gal, Jean-François; Maria, Pierre-Charles; Zerbinati, Orfeo

    2004-11-01

    The aim of the study was to analyse BTEX compounds (benzene, toluene, ethylbenzene, xylenes) in air by solid phase micro-extraction/gas chromatography/mass spectrometry (SPME/GC/MS), and this article presents the features of the calibration method proposed. Examples of real-world air analysis are given. Standard gaseous mixtures of BTEX in air were generated by dynamic dilution. SPME sampling was carried out under non-equilibrium conditions using a Carboxen/PDMS fibre exposed for 30 min to standard gas mixtures or to ambient air. The behaviour of the analytical response was studied from 0 to 65 microg/m3 by adding increasing amounts of BTEX to the air matrix. Detection limits range from 0.05 to 0.1 microg/m3 for benzene, depending on the fibre. Inter-fibre relative standard deviations (reproducibility) are larger than 18%, although the repeatability for an individual fibre is better than 10%. Therefore, each fibre should be considered to be a particular sampling device, and characterised individually depending on the required accuracy. Sampling indoor and outdoor air by SPME appears to be a suitable short-delay diagnostic method for volatile organic compounds, taking advantage of short sampling time and simplicity.

  2. An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

    NASA Astrophysics Data System (ADS)

    Obersteiner, F.; Bönisch, H.; Engel, A.

    2015-09-01

    We present the characterization and application of a new gas chromatography-time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δ m of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 Th/Th and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found around 5 ppm after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits were as low as a few femtograms as mass traces could be made highly specific for selected molecule fragments with the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. The TOFMS was found to be linear within a concentration range from about 1 pg to 1 ng of analyte per Liter of air. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straight-forward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well-suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, low resolution quadrupole MS and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

  3. HEPA air filter (image)

    MedlinePlus

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  4. Influence of air mass source region on nanoparticle events and hygroscopicity in central Virginia, U.S.

    NASA Astrophysics Data System (ADS)

    O'Halloran, T. L.; Fuentes, J. D.; Collins, D. R.; Cleveland, M. J.; Keene, W. C.

    During autumn, 2006, variation in the frequency of aerosol nucleation events, as inferred from nanoparticle growth events, and associated hygroscopicity were investigated as a function of air mass transport history at a mixed deciduous forest in central Virginia, U.S. Above-canopy size distributions of aerosols between 0.012 and 0.700 μm diameter, size-resolved particle hygroscopicity at eight dry diameters between 0.012 and 0.400 μm, and cloud condensation nuclei (CCN) activity were characterized. Air mass back trajectories were clustered to identify source regions. Growth events were most frequent in fast-moving air masses (mean = 9 m s -1) that originated over the north central U.S. Under these flow regimes, mean values for preexisting sub-μm aerosol number concentrations (4700 cm -3), corresponding surface area (142 μm 2 cm -3), air temperature (6.2 °C), and relative humidity (RH, 49.4%) were relatively low compared to other regimes. Under stagnant flow conditions (mean = 3 m s -1), mean number concentrations were higher (>6000 cm -3) and size fractions <0.1 μm diameter exhibited enhanced hygroscopicity compared to other source regions. These results indicate that precursors emitted into relatively clean, cold, and dry air transported over the southeastern U.S. reacted to form condensable intermediates that subsequently produced new aerosols via nucleation and growth. This pathway was an important source for CCN. During events in October, nanoparticles were produced in greater numbers and grew more rapidly compared to November and December.

  5. On the relationship between Arctic ice clouds and polluted air masses over the North Slope of Alaska in April 2008

    NASA Astrophysics Data System (ADS)

    Jouan, C.; Pelon, J.; Girard, E.; Ancellet, G.; Blanchet, J. P.; Delanoë, J.

    2014-02-01

    Recently, two types of ice clouds (TICs) properties have been characterized using the Indirect and Semi-Direct Aerosol Campaign (ISDAC) airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (< 10 L-1) and larger (> 110 μm) ice crystals, and a larger ice supersaturation (> 15%) compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nucleating properties of ice nuclei (IN) through acidification, resulting in a smaller concentration of larger ice crystals and leading to precipitation (e.g., cloud regime TIC-2B). Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from three potential SO2 emission sources into Alaska: eastern China and Siberia where anthropogenic and biomass burning emissions, respectively, are produced, and the volcanic region of the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China and Siberia over Alaska, most probably with the contribution of acidic volcanic aerosol during the TIC-2B period. Observation Monitoring Instrument (OMI) satellite observations reveal that SO2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results support the hypothesis that acidic coating on IN could be at the origin of the formation of TIC-2B.

  6. On the relationship between Arctic ice clouds and polluted air masses over the north slope of Alaska in April 2008

    NASA Astrophysics Data System (ADS)

    Jouan, C.; Pelon, J.; Girard, E.; Ancellet, G.; Blanchet, J. P.; Delanoë, J.

    2013-02-01

    Recently, two Types of Ice Clouds (TICs) properties have been characterized using ISDAC airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (<10 L-1) and larger (>110 μm) ice crystals, a larger ice supersaturation (>15%) and a fewer ice nuclei (IN) concentration (<2 order of magnitude) when compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nucleating properties of IN through acidification, resulting to a smaller concentration of larger ice crystals and leading to precipitation (e.g. cloud regime TIC-2B) because of the reduced competition for the same available moisture. Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from the three potentials SO2 emission areas to Alaska: eastern China and Siberia where anthropogenic and biomass burning emission respectively are produced and the volcanic region from the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China/Siberia over Alaska, most probably with the contribution of acid volcanic aerosol during the TIC-2B period. OMI observations reveal that SO2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results strongly support the hypothesis that acidic coating on IN are at the origin of the formation of TIC-2B.

  7. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall.

    PubMed

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-11-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005-2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination.

  8. Influence of power ultrasound application on mass transport and microstructure of orange peel during hot air drying

    NASA Astrophysics Data System (ADS)

    Ortuño, Carmen; Pérez-Munuera, Isabel; Puig, Ana; Riera, Enrique; Garcia-Perez, J. V.

    2010-01-01

    Power ultrasound application on convective drying of foodstuffs may be considered an emergent technology. This work deals with the influence of power ultrasound on drying of natural materials addressing the kinetic as well as the product's microstructure. Convective drying kinetics of orange peel slabs (thickness 5.95±0.41 mm) were carried out at 40 ∘C and 1 m/s with (US) and without (AIR) power ultrasound application. A diffusion model considering external resistance to mass transfer was considered to describe drying kinetics. Fresh, US and AIR dried samples were analyzed using Cryo-SEM. Results showed that drying kinetics of orange peel were significantly improved by the application of power ultrasound. From modeling, it was observed a significant (p¡0.05) increase in both mass transfer coefficient and effective moisture diffusivity. The effects on mass transfer properties were confirmed from microestructural observations. In the cuticle surface, the pores were obstructed by wax components scattering, which evidence the ultrasonic effects on the interfaces. The cells of the flavedo were compressed and large intercellular air spaces were generated in the albedo facilitating water transfer through it.

  9. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall

    PubMed Central

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-01-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005–2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination. PMID:24722630

  10. Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

    NASA Technical Reports Server (NTRS)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2012-01-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote

  11. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-03-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. OMI observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the tropospheric NO2 AMF calculation by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model for cloud-free scenes. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation (SD) of the difference was 0.6 ± 8%. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 72% of the daily OMAERUV AOD observations were within 0.3 of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10% higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30%, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and explicit aerosol parameters is on average 6 and 3

  12. An ion-drag air mass-flow sensor for automotive applications

    SciTech Connect

    Malaczynski, G.W.; Schroeder, T. )

    1992-04-01

    An air-flow meter, developed primarily for the measurement of intake air flow into an internal combustion engine, is described. The well-known process of corona ion deflection in a gas flow together with proper electrode geometry and a detection scheme provides the conceptual basis for a humidity-insensitive ionic air-flow sensor. Output characteristics of the sensor, such as response time and range of operation, are discussed and compared with those of a production hot-wore meter for the type that is currently used with electronic fuel injection systems.

  13. Traffic-related air pollution and circulating levels of total and allergen-specific IgE among children in Detroit, Michigan

    EPA Science Inventory

    Introduction: There is a growing body of literature suggesting a relationship between traffic-related air pollution and allergic health outcomes. Animal studies have demonstrated that air pollution, particularly diesel exhaust particles, may stimulate or enhance atopic responses...

  14. Surface analysis using a new plasma assisted desorption/ionisation source for mass spectrometry in ambient air

    NASA Astrophysics Data System (ADS)

    Bowfield, A.; Barrett, D. A.; Alexander, M. R.; Ortori, C. A.; Rutten, F. M.; Salter, T. L.; Gilmore, I. S.; Bradley, J. W.

    2012-06-01

    The authors report on a modified micro-plasma assisted desorption/ionisation (PADI) device which creates plasma through the breakdown of ambient air rather than utilising an independent noble gas flow. This new micro-PADI device is used as an ion source for ambient mass spectrometry to analyse species released from the surfaces of polytetrafluoroethylene, and generic ibuprofen and paracetamol tablets through remote activation of the surface by the plasma. The mass spectra from these surfaces compare favourably to those produced by a PADI device constructed using an earlier design and confirm that the new ion source is an effective device which can be used to achieve ambient mass spectrometry with improved spatial resolution.

  15. Measurement of Circulating 1,25-Dihydroxyvitamin D: Comparison of an Automated Method with a Liquid Chromatography Tandem Mass Spectrometry Method

    PubMed Central

    Zittermann, Armin; Ernst, Jana B.; Becker, Tobias; Dreier, Jens; Knabbe, Cornelius; Gummert, Jan F.; Kuhn, Joachim

    2016-01-01

    Background. The clinical relevance of circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) is probably underappreciated, but variations in the measurement of this difficult analyte between different methods limit comparison of results. Methods. In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit. Results. Median (interquartile range) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5–39.0 pg/mL) and 23.6 pg/mL (16.1–31.3 pg/mL), respectively (P = 0.001). Using the method-specific cut-offs for deficient 1,25(OH)2D levels (<20 pg/mL for the automated assay and <17 pg/mL for the LC-MS/MS method), the percentage of patients classified as 1,25(OH)2D deficient was 28.7% and 27.1%, respectively. However, concordance between the two methods for deficient levels was only 62% and the concordance correlation coefficient was poor (0.534). The regression equation resulted in an intercept of −1.99 (95% CI: −7.33–1.31) and a slope of 1.27 (95% CI: 1.04–1.52) for the automated assay. The mean bias with respect to the mean of the two methods was −3.8 (1.96 SD: −28.3–20.8) pg/mL for the LC-MS/MS method minus the automated assay. Conclusions. The two methods show only modest correlation and further standardization is required to improve reliability and comparability of 1,25(OH)2D test procedures. PMID:27127512

  16. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  17. Chemical and Trajectory Analysis of an Air Mass Plume from Asia

    NASA Astrophysics Data System (ADS)

    Guo, J. J.; Marrero, J. E.; Blake, D. R.

    2014-12-01

    Tracking the source of pollution events is important in understanding the transport of pollution plumes and impact on areas far from the source. Previous studies have shown that the rising contribution of Asian air pollution to the US has increased the number of days that pollution events exceed National Ambient Air Quality Standards (NAAQS). Whole air samples collected over the Edwards Air Force Base during a June 2014 NASA Student Airborne Research Program (SARP) flight exhibited enhancements in the concentrations of several compounds between 23-32 thousand feet. Chemical tracer analysis of these high altitude samples reveal that the air does not correspond to California emitted air. Chemical signatures in the plume, including high levels of OCS, chloroform, and methyl chloride, and low levels of methyl bromide, indicate that the plume was most heavily influence by coal combustion with contributions from biomass burning events from Asia. Low concentrations of ethene at the high altitude despite enhanced concentrations of ethane and ethyne suggest that this plume was aged. Further analysis of the plume using meteorological wind trajectories reveal that the plume had originated in China approximately 4-5 days prior. This is faster than results from previous studies that had found a Spring transport time of approximately 6 days.

  18. Peripheral circulation.

    PubMed

    Laughlin, M Harold; Davis, Michael J; Secher, Niels H; van Lieshout, Johannes J; Arce-Esquivel, Arturo A; Simmons, Grant H; Bender, Shawn B; Padilla, Jaume; Bache, Robert J; Merkus, Daphne; Duncker, Dirk J

    2012-01-01

    Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.

  19. A Comparison of the Red Green Blue (RGB) Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles and NOAA G-IV Dropsondes

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Folmer, Michael; Dunion, Jason

    2014-01-01

    RGB air mass imagery is derived from multiple channels or paired channel differences. The combination of channels and channel differences means the resulting imagery does not represent a quantity or physical parameter such as brightness temperature in conventional single channel imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles and NOAA G-IV dropsondes provide insight about the vertical structure of the air mass represented on the RGB air mass imagery and are a first step to validating the imagery.

  20. Influence of pregnancy in mid-to-late gestation on circulating metabolites, visceral organ mass, and abundance of proteins relating to energy metabolism in mature beef cows.

    PubMed

    Wood, K M; Awda, B J; Fitzsimmons, C; Miller, S P; McBride, B W; Swanson, K C

    2013-12-01

    In mid-to-late gestation, nutrient demand increases to meet the growth requirements of the conceptus and cows may alter metabolism in response to energy demands of pregnancy. By better understanding the metabolic role of pregnancy, there may be opportunities to better understand maintenance energy costs and improve overall feed efficiency. Eighteen mature Simmental/Angus crossbred cows, pregnant (PREG; n = 9) and nonpregnant (OPEN; n = 9), were used to investigate the effect of pregnancy on BW change, carcass traits, visceral organ mass, and circulating serum metabolites. Cows were blocked by day of expected parturition such that each block was slaughtered 4 to 5 wk before parturition. Cows were individually fed for ad libitum intake using Calan gates for 89 to 105 d. Cows were weighed, ultrasounded for rib (over the 12th and 13th rib) and rump fat, and a serum sample obtained at d 1, 56, and 3 to 5 d before slaughter. At slaughter, organs were removed, trimmed of fat, and weighed. Serum was analyzed for β-hydroxybutyrate (BHBA), NEFA, glucose, urea, total cholesterol, and triiodothyronine (T3). Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papillae, pancreas, and small intestinal mucosa were collected at slaughter and snap frozen in liquid N. Western blots were conducted to quantify abundance of: proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na(+)/K+ ATPase for all tissues; PPARγ, PPARγ coactivator 1α (PGC1-α), 5'-adenosine monophosphate-activated protein kinase (AMPK) and phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Data were analyzed using PROC MIXED in SAS as a replicated randomized complete block. Liver weights (actual, relative to BW, relative to HCW) were heavier (P ≤ 0.02) in OPEN. Rumen mass and kidney fat weight, both relative to BW, were also greater (P ≤ 0.04) in OPEN. On d 56

  1. Long-term Trend of Cold Air Mass Amount below a Designated Potential Temperature in Northern and Southern Hemisphere Winters with 7 Different Reanalysis Datasets

    NASA Astrophysics Data System (ADS)

    Kanno, Y.; Abdillah, M. R.; Iwasaki, T.

    2015-12-01

    This study addresses that the hemispheric total cold air mass amount defined below a threshold potential temperature of 280 K is a good indicator of the long-term trend of climate change in the polar region. We demonstrate quantitative analyses of warming trend in the Northern Hemisphere (NH) and Southern Hemisphere (SH) winters, using 7 different reanalysis datasets (JRA-55, JRA-55C, JRA-55AMIP, ERA-interim, CFSR, JRA-25, NCEP-NCAR). Hemispheric total cold air mass amount in the NH winter exhibit a statistically significant decreasing trend in all reanalysis datasets at a rate about -1.37 to -0.77% per decade over the period 1959-2012 and at a rate about -1.57 to -0.82% per decade over 1980-2012. There is no statistically significant trend in the equatorward cold air mass flux across latitude of 45N, which is an indicator for hemispheric-scale cold air outbreak, over the period 1980-2012 except for NCEP-NCAR reanalysis dataset which shows substantial decreasing trend of about -3.28% per decade. The spatial distribution of the long-term trend of cold air mass amount in the NH winter is almost consistent among reanalysis datasets except for JRA-55AMIP over the period 1980-2012. Cold air mass amount increases over Central Siberia, Kamchatka peninsula, and Bering Sea, while it decreases over Norwegian Sea, Barents Sea, Kara Sea, Greenland, Canada, Northern part of United States, and East Asia. In the SH winter, on the other hand, there is a large discrepancy in hemispheric total cold air mass amount and equatorward cold air mass flux across latitude of 50S over the period 1980-2010 among reanalysis datasets. This result indicate that there is a large uncertainty in the long-term trend of cold air mass amount in the SH winter.

  2. Use of Chiral Signatures of Organochlorine Pesticides in Asian, Trans-Pacific, and Western U.S. Air Masses to Identify Source Regions

    NASA Astrophysics Data System (ADS)

    Simonich, S.; Genualdi, S.; Primbs, T.; Ryoo, K.; Bidleman, T.; Jantunen, L.

    2008-12-01

    Chiral signatures of organochlorine pesticides were measured in air masses on Okinawa Japan and three remote locations in the Pacific Northwestern U.S.: Cheeka Peak Observatory (CPO), a coastal site on the Olympic Peninsula of Washington at 500 m; Mary's Peak Observatory (MPO), a site at 1250 m in Oregon's Coast range; and Mt. Bachelor Observatory (MBO), a site at 2300 m in Oregon's Cascade range. The chiral signature of composite soil samples collected from agricultural areas in China and South Korea were also measured. Racemic alpha-HCH was measured in Asian air masses and soil from China and South Korea. Non-racemic (enantiomer fraction (EF) = 0.528 ± 0.0048) alpha-HCH was measured in regional air masses at CPO, a marine boundary layer site, and may reflect volatilization from the Pacific Ocean and regional soils. However, during trans-Pacific transport events at CPO, the EFs were significantly (p-value <0.001) more racemic (EF = 0.513 ± 0.0003). Racemic alpha-HCH was consistently measured in trans- Pacific air masses at MPO and MBO. The alpha-HCH EFs in CPO, MPO, and MBO air masses were positively correlated (p-value = 0.0017) with the amount of time the air mass spent above the boundary layer along the 10-day back air mass trajectory prior to being sampled. This suggests that the alpha-HCH in the free troposphere is racemic. The racemic signatures of cis and trans chlordane in air masses at all four air sampling sites suggest that Asian and U.S. urban areas continue to be sources of chlordanes that have not yet undergone biotransformation.

  3. Retrospective screening of pesticide metabolites in ambient air using liquid chromatography coupled to high-resolution mass spectrometry.

    PubMed

    López, Antonio; Yusà, Vicent; Millet, Maurice; Coscollà, Clara

    2016-04-01

    A new methodology for the retrospective screening of pesticide metabolites in ambient air was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS), including two systematic workflows (i) post-run target screening (suspect screening) and (ii) non-target screening. An accurate-mass database was built and used for the post-run screening analysis. The database contained 240 pesticide metabolites found in different matrixes such as air, soil, water, plants, animals and humans. For non-target analysis, a "fragmentation-degradation" relationship strategy was selected. The proposed methodology was applied to 31 air samples (PM10) collected in the Valencian Region (Spain). In the post-target analysis 34 metabolites were identified, of which 11 (3-ketocarburan, carbofuran-7-phenol, carbendazim, desmethylisoproturon, ethiofencarb-sulfoxide, malaoxon, methiocarb-sulfoxide, N-(2-ethyl-6-methylphenyl)-L-alanine, omethoate, 2-hydroxy-terbuthylazine, and THPAM) were confirmed using analytical standards. The semiquantitative estimated concentration ranged between 6.78 and 198.31 pg m(-3). Likewise, two unknown degradation products of malaoxon and fenhexamid were elucidated in the non-target screening. PMID:26838378

  4. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Curci, G.

    2014-11-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyse aerosol optical depth τa(z) values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean τa(3.5 km) ∼ 0.04 - and shows a seasonal trend with a winter minimum - τa(3.5 km) ∼ 0.03 -, and a summer maximum - τa(3.5 km) ∼ 0.06 -, and an unexpected increase from August to September - τa(3.5 km) ∼ 0.055. We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from the Pacific Ocean. Average concentrations are affected by continental sources (wind-blown dust and urban pollution), whilst the peak observed in September and October could be linked to biomass burning in the northern part of Argentina or air pollution coming from surrounding urban areas.

  5. Thermal desorption-gas chromatography-mass spectrometry method to determine phthalate and organophosphate esters from air samples.

    PubMed

    Aragón, M; Borrull, F; Marcé, R M

    2013-08-16

    A method based on thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed to determine four organophosphate esters, seven phthalate esters, and bis(2-ethylhexyl) adipate in the gas phase from harbour and urban air samples. The method involves the sampling of 1.5L of air in a Tenax TA sorbent tube followed by thermal desorption (using a Tenax TA cryogenic trap) coupled to gas chromatography-mass spectrometry. The repeatability of the method expressed as %RSD (n=3) is less than 15% and the MQLs are between 0.007μgm(-3) (DMP, TBP, BBP, TPP and DnOP) and 6.7μgm(-3) (DEHP). The method was successfully applied in two areas (urban and harbour) testing two and three points in each one, respectively. Some of these compounds were found in both urban and harbour samples. Di-(2-ethylhexyl)phthalate was the most abundant compound found in both areas at concentration levels between 6.7μgm(-3) and 136.4μgm(-3). This study demonstrates that thermal desorption is an efficient method for the determination of these semi-volatile compounds in the gas phase fraction of air samples.

  6. Retrospective screening of pesticide metabolites in ambient air using liquid chromatography coupled to high-resolution mass spectrometry.

    PubMed

    López, Antonio; Yusà, Vicent; Millet, Maurice; Coscollà, Clara

    2016-04-01

    A new methodology for the retrospective screening of pesticide metabolites in ambient air was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS), including two systematic workflows (i) post-run target screening (suspect screening) and (ii) non-target screening. An accurate-mass database was built and used for the post-run screening analysis. The database contained 240 pesticide metabolites found in different matrixes such as air, soil, water, plants, animals and humans. For non-target analysis, a "fragmentation-degradation" relationship strategy was selected. The proposed methodology was applied to 31 air samples (PM10) collected in the Valencian Region (Spain). In the post-target analysis 34 metabolites were identified, of which 11 (3-ketocarburan, carbofuran-7-phenol, carbendazim, desmethylisoproturon, ethiofencarb-sulfoxide, malaoxon, methiocarb-sulfoxide, N-(2-ethyl-6-methylphenyl)-L-alanine, omethoate, 2-hydroxy-terbuthylazine, and THPAM) were confirmed using analytical standards. The semiquantitative estimated concentration ranged between 6.78 and 198.31 pg m(-3). Likewise, two unknown degradation products of malaoxon and fenhexamid were elucidated in the non-target screening.

  7. Influence of trans-boundary biomass burning impacted air masses on submicron particle number concentrations and size distributions

    NASA Astrophysics Data System (ADS)

    Betha, Raghu; Zhang, Zhe; Balasubramanian, Rajasekhar

    2014-08-01

    Submicron particle number concentration (PNC) and particle size distribution (PSD) in the size range of 5.6-560 nm were investigated in Singapore from 27 June 2009 through 6 September 2009. Slightly hazy conditions lasted in Singapore from 6 to 10 August. Backward air trajectories indicated that the haze was due to the transport of biomass burning impacted air masses originating from wild forest and peat fires in Sumatra, Indonesia. Three distinct peaks in the morning (08:00-10:00), afternoon (13:00-15:00) and evening (16:00-20:00) were observed on a typical normal day. However, during the haze period no distinct morning and afternoon peaks were observed and the PNC (39,775 ± 3741 cm-3) increased by 1.5 times when compared to that during non-haze periods (26,462 ± 6017). The morning and afternoon peaks on the normal day were associated with the local rush hour traffic while the afternoon peak was induced by new particle formation (NPF). Diurnal profiles of PNCs and PSDs showed that primary particle peak diameters were large during the haze (60 nm) period when compared to that during the non-haze period (45.3 nm). NPF events observed in the afternoon period on normal days were suppressed during the haze periods due to heavy particle loading in atmosphere caused by biomass burning impacted air masses.

  8. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-09-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. Satellite observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the Ozone Monitoring Instrument (OMI) tropospheric NO2 AMF calculation for cloud-free scenes. We do so by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation of the difference was 0.6 ± 8 %. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 68 % of the daily OMAERUV AOD observations were within 30 % of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10 % higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30 %, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and

  9. An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

    NASA Astrophysics Data System (ADS)

    Obersteiner, F.; Bönisch, H.; Engel, A.

    2016-01-01

    We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

  10. Air mass origin and its influence on radionuclide activities ( 7Be and 210Pb) in aerosol particles at a coastal site in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Dueñas, C.; Orza, J. A. G.; Cabello, M.; Fernández, M. C.; Cañete, S.; Pérez, M.; Gordo, E.

    2011-07-01

    Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of 7Be and 210Pb in aerosols at Málaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2000-2006 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory clusters. The average concentration values of 7Be and 210Pb over the 7 year period have been found to be 4.6 and 0.58 mBq m -3, respectively, with mean aerosol mass concentration of 53.6 μg m -3. The identified air flow types arriving at Málaga reflect the transitional location of the Iberian Peninsula and show significant differences in radionuclide activities. Air concentrations of both nuclides and the aerosol mass concentration are controlled predominantly by the synoptic scenarios leading to the entrance of dust-laden continental flows from northern Africa and the arrival of polar maritime air masses, as implied by the strong correlations found between the monthly frequencies of the different air masses and the specific activities of both radionuclides. Correlations between activity concentrations and precipitation are significant though lower than with air masses.

  11. [Determination of volatile organic compounds in ambient air by thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry].

    PubMed

    Feng, Lili; Hu, Xiaofang; Yu, Xiaojuan; Zhang, Wenying

    2016-02-01

    A method was established for the simultaneous determination of 23 volatile organic compounds (VOCs) in ambient air with combination of thermal desorption (TD) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). The air samples were collected by active sampling method using Tenax-TA sorbent tubes, and desorbed by thermal desorption. The analytes were determined by GC-MS/MS in selected reaction monitoring (SRM) mode, and internal standard method was applied to quantify the VOCs. The results of all the 23 VOCs showed good linearities in low level (0. 01-1 ng) and high level (1-100 ng) with all the correlation coefficients (r2) more than 0. 99. The method quantification limits were between 0. 000 08-1 µg/m3. The method was validated by means of recovery experiments (n = 6) at three spiked levels of 2, 10 and 50 ng. The recoveries between 77% and 124% were generally obtained. The relative standard deviations (RSDs) in all cases were lower than 20%, except for chlorobenzene at the low spiked level. The developed method was applied to determine VOCs in ambient air collected at three sites in Shanghai. Several compounds, like benzene, toluene, ethylbenzene, m-xylenes, p-xylenes, styrene, 1, 2, 4-trimethylbenzene and hexachlorobutadiene were detected and confirmed in all the samples analyzed. The method is highly accurate, reliable and sensitive for monitoring the VOCs in ambient air. PMID:27382728

  12. Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

    2015-12-01

    Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air. PMID:26493981

  13. Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

    2015-12-01

    Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

  14. Modeling 3D conjugate heat and mass transfer for turbulent air drying of Chilean papaya in a direct contact dryer

    NASA Astrophysics Data System (ADS)

    Lemus-Mondaca, Roberto A.; Vega-Gálvez, Antonio; Zambra, Carlos E.; Moraga, Nelson O.

    2016-03-01

    A 3D model considering heat and mass transfer for food dehydration inside a direct contact dryer is studied. The k- ɛ model is used to describe turbulent air flow. The samples thermophysical properties as density, specific heat, and thermal conductivity are assumed to vary non-linearly with temperature. FVM, SIMPLE algorithm based on a FORTRAN code are used. Results unsteady velocity, temperature, moisture, kinetic energy and dissipation rate for the air flow are presented, whilst temperature and moisture values for the food also are presented. The validation procedure includes a comparison with experimental and numerical temperature and moisture content results obtained from experimental data, reaching a deviation 7-10 %. In addition, this turbulent k- ɛ model provided a better understanding of the transport phenomenon inside the dryer and sample.

  15. Implementation of Tritium in the Lmdz-Iso General Circulation Model: First Promising Results for the Study of the Relationships Between Stratospheric Air Inputs into the Lower Troposphere in Polar Regions, Water Cycle and Climate

    NASA Astrophysics Data System (ADS)

    Cauquoin, A.; Jean Baptiste, P.; Risi, C. M.; Fourre, E.; Landais, A.

    2014-12-01

    Understanding the links between climate and water cycle is essential in the current context of global warming. The water isotopic composition, quantified as δD, δ18O or δ17O, has a great potential to trace the organization of present-day hydrological cycle. When recorded in various archives as tree rings, sediments, ice cores, they have also been largely used to reconstruct the past evolution of climate and water. The Antarctic cap is extremely sensitive to climate change. Moreover, this region is under the influence of exchanges between the troposphere and the stratosphere because of the presence of the polar vortex. Tritium (3H) has been shown to be an appropriate tracer for the intrusion of stratospheric air masses into the lower troposphere. Natural tritium is mainly produced by the interaction of cosmic radiations with the upper atmosphere. This tritium enters the hydrological cycle in the form of tritiated water molecules (HTO) and has a radioactive half-life of 4500±8 days. In an approach combining data and model, we have first implemented tritium in the coupled Laboratoire de Météorologie Dynamique Zoom (LMDZ) Atmospheric General Circulation Model developed at IPSL [Risi et al., 2010]: LMDZ-iso. The implementation of natural tritium uses the same model architecture as for the other water isotopes, after a correct description of associated cosmogenic production terms [Masarik and Beer, 2009]. The model is used in a configuration dedicated to the simulation of the stratosphere, with 39 layers. In this presentation, we will focus on the modeling of spatial and temporal natural variations of tritium content in precipitation. The model is validated against a compilation of available data for natural tritium. We show that the continental and latitudinal effects are well reproduced by the model and that simulated seasonal variations of the tritium content of precipitation are coherent with our current knowledge of troposphere-stratosphere exchanges. Masarik

  16. Continental Land Mass Air Traffic Control (COLM ATC). [using three artificial satellite configurations

    NASA Technical Reports Server (NTRS)

    Pecar, J. A.; Henrich, J. E.

    1973-01-01

    The application of various satellite systems and techniques relative to providing air traffic control services for the continental United States was studied. Three satellite configurations were reviewed. The characteristics and capabilities of the satellites are described. The study includes consideration for the various ranging waveforms, multiple access alternatives, and the power and bandwidth required as a function of the number of users.

  17. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    SciTech Connect

    McJimpsey, E L; Steele, P T; Coffee, K R; Fergenson, D P; Riot, V J; Woods, B W; Gard, E E; Frank, M; Tobias, H J; Lebrilla, C

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  18. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    SciTech Connect

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-18

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  19. Smart tetroons for Lagrangian air-mass tracking during ACE 1

    NASA Astrophysics Data System (ADS)

    Businger, Steven; Johnson, Randy; Katzfey, Jack; Siems, Steven; Wang, Qing

    1999-05-01

    A series of "smart" tetroons was released from shipboard during the recent ACE 1 field experiment designed to monitor changes in the sulfur budget in a remote marine boundary layer (MBL) south of Tasmania, Australia. The smart tetroons were designed at NOAA Air Resources Laboratory Field Research Division to provide air parcel tracking information. The adjective smart here refers here to the fact that the buoyancy of the tetroons automatically adjusts through the action of a pump and valves when the tetroon travels vertically outside a range of pressures set prior to tetroon release. The smart tetroon design provides GPS location, barometric pressure, temperature, relative humidity, and tetroon status data via a transponder to the NCAR C-130 research aircraft flying in the vicinity of the tetroons. In this paper we will describe (1) the design and capability of the smart tetroons and their performance during the two Lagrangian experiments conducted during ACE 1, (2) the synoptic context of the Lagrangians, including the origin of the air parcels being tracked, and (3) the results of trajectory predictions derived from the National Center for Environmental Prediction (NCEP) Global Spectral Model (GSM) and Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Atmospheric Research (DAR) limited-area model.

  20. Mass transfer of volatile organic compounds from drinking water to indoor air: The role of residential dishwashers

    SciTech Connect

    Howard-Reed, C.; Corsi, R.L.; Moya, J.

    1999-07-01

    Contaminated tap water may be a source of volatile organic compounds (VOCs) in residential indoor air. To better understand the extent and impact of chemical emissions from this source, a two-phase mass balance model was developed based on mass transfer kinetics between each phase. Twenty-nine experiments were completed using a residential dishwasher to determine model parameters. During each experiment, inflow water was spiked with a cocktail of chemical tracers with a wide range of physicochemical properties. In each case, the effects of water temperature, detergent, and dish-loading pattern on chemical stripping efficiencies and mass transfer coefficients were determined. Dishwasher headspace ventilation rates were also measured using an isobutylene tracer gas. Chemical stripping efficiencies for a single cycle ranged from 18% to 55% for acetone, from 96% to 98% for toluene, and from 97% to 98% for ethylbenzene and were consistently 100% for cyclohexane. Experimental results indicate that dishwashers have a relatively low but continuous ventilation rate that results in significant chemical storage within the headspace of the dishwasher. In conjunction with relatively high mass transfer coefficients, low ventilation rates generally lead to emissions that are limited by equilibrium conditions after approximately 1--2 min of dishwasher operation.

  1. Interaction of clothing and body mass index affects validity of air displacement plethysmography in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Examine the effect of alternate clothing schemes on validity of Bod Pod to estimate percent body fat (BF) compared to dual x-ray absorptiometry (DXA), and determine if these effects differ by body mass index (BMI). Design: Cross-sectional Subjects: 132 healthy adults aged 19-81 classifi...

  2. Determination of cooling air mass flow for a horizontally-opposed aircraft engine installation

    NASA Technical Reports Server (NTRS)

    Miley, S. J.; Cross, E. J., Jr.; Ghomi, N. A.; Bridges, P. D.

    1979-01-01

    The relationship between the amount of cooling air flow and the corresponding flow pressure difference across an aircraft engine was investigated in flight and on the ground. The flight test results were consistent with theory, but indicated a significant installation leakage problem. A ground test blower system was used to identify and reduce the leakage. The correlation between ground test cell determined engine orifice characteristics and flight measurements showed good agreement if the engine pressure difference was based on total pressure rather than static pressure.

  3. Circulation in gas-slurry column reactors

    SciTech Connect

    Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.

    1990-08-15

    Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.

  4. An air-mass trajectory study of the transport of radioactivity from Fukushima to Thessaloniki, Greece and Milan, Italy

    NASA Astrophysics Data System (ADS)

    Ioannidou, A.; Giannakaki, E.; Manolopoulou, M.; Stoulos, S.; Vagena, E.; Papastefanou, C.; Gini, L.; Manenti, S.; Groppi, F.

    2013-08-01

    Analyses of 131I, 137Cs and 134Cs in airborne aerosols were carried out in daily samples at two different sites of investigation: Thessaloniki, Greece (40° N) and Milan, Italy (45° N) after the Fukushima accident during the period of March-April, 2011. The radionuclide concentrations were determined and studied as a function of time. The 131I concentration in air over Milan and Thessaloniki peaked on April 3-4, 2011, with observed activities 467 μBq m-3 and 497 μBq m-3, respectively. The 134Cs/137Cs activity ratio values in air were around 1 in both regions, related to the burn-up history of the damaged nuclear fuel of the destroyed nuclear reactor. The high 131I/137Cs ratio, observed during the first days after the accident, followed by lower values during the following days, reflects not only the initial release ratio but also the different volatility, attachment and removal of the two isotopes during transportation due to their different physico-chemical properties. No artificial radionuclides could be detected in air after April 28, 2011 in both regions of investigation. The different maxima of airborne 131I and 134,137Cs in these two regions were related to long-range air mass transport from Japan, across the Pacific and to Central Europe. Analysis of backward trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. HYSPLIT backward trajectories were applied for the interpretation of activity variations of measured radionuclides.

  5. Numerical simulation for the influence of laser-induced plasmas addition on air mass capture of hypersonic inlet

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Dou, Zhiguo; Li, Qian

    2012-03-01

    The theory of laser-induced plasmas addition to hypersonic airflow off a vehicle to increase air mass capture and improve the performance of hypersonic inlets at Mach numbers below the design value is explored. For hypersonic vehicles, when flying at mach numbers lower than the design one, we can increase the mass capture ratio of inlet through laser-induced plasmas injection to the hypersonic flow upstream of cowl lip to form a virtual cowl. Based on the theory, the model of interaction between laser-induced plasmas and hypersonic flow was established. The influence on the effect of increasing mass capture ratio was studied at different positions of laser-induced plasmas region for the external compression hypersonic inlet at Mach 5 while the design value is 6, the power of plasmas was in the range of 1-8mJ. The main results are as follows: 1. the best location of the plasma addition region is near the intersection of the nose shock of the vehicle with the continuation of the cowl line, and slightly below that line. In that case, the shock generated by the heating is close to the shock that is a reflection of the vehicle nose shock off the imaginary solid surface-extension of the cowl. 2. Plasma addition does increase mass capture, and the effect becomes stronger as more energy is added, the peak value appeared when the power of plasma was about 4mJ, when the plasma energy continues to get stronger, the mass capture will decline slowly.

  6. Influence of dissolved humic substances on the mass transfer of organic compounds across the air-water interface.

    PubMed

    Ramus, Ksenia; Kopinke, Frank-Dieter; Georgi, Anett

    2012-01-01

    The effect of dissolved humic substances (DHS) on the rate of water-gas exchange of two volatile organic compounds was studied under various conditions of agitation intensity, solution pH and ionic strength. Mass-transfer coefficients were determined from the rate of depletion of model compounds from an apparatus containing a stirred aqueous solution with continuous purging of the headspace above the solution (dynamic system). Under these conditions, the overall transfer rate is controlled by the mass-transfer resistance on the water side of the water-gas interface. The experimental results show that the presence of DHS hinders the transport of the organic molecules from the water into the gas phase under all investigated conditions. Mass-transfer coefficients were significantly reduced even by low, environmentally relevant concentrations of DHS. The retardation effect increased with increasing DHS concentration. The magnitude of the retardation effect on water-gas exchange was compared for Suwannee River fulvic and humic acids, a commercially available leonardite humic acid and two synthetic surfactants. The observed results are in accordance with the concept of hydrodynamic effects. Surface pressure forces due to surface film formation change the hydrodynamic characteristics of water motion at the water-air interface and thus impede surface renewal.

  7. How much do carbon isotope measurements constrain glacial ocean circulation?

    NASA Astrophysics Data System (ADS)

    Schmittner, A.; Mix, A. C.

    2010-12-01

    Reconstructions of the isotopic composition of dissolved inorganic carbon in seawater (d13DIC) are often interpreted as a ventilation or circulation proxy in paleoceanography. The modern deep-sea distribution of d13C in dissolved inorganic carbon (d13DIC) is highly anti-correlated to macronutrient (PO4, NO3) and apparent oxygen utilization (AOU) patterns due to fractionation during photosynthetic carbon uptake by phytoplankton. Nutrient and AOU concentrations in freshly ventilated North Atlantic Deep Water, for example, are low (d13DIC is high), whereas older water masses contain more respired nutrients and (isotopically light) carbon and have high AOU. However, d13DIC is also influenced by fractionation during air sea gas exchange - a process that decouples d13DIC from changes in nutrients and AOU. Moreover, biological fractionation is not constant but spatially and temporally variable. Here we are using a new global three-dimensional model of stable carbon isotope cycling that includes variable biological and air-sea gas exchange fractionation effects in conjunction with modern and glacial d13C observations to reconstruct ocean circulation patterns. Model versions with different rates and patterns of ocean circulation are produced and the resulting d13C patterns are compared to a compilation of measurements from ocean sediment cores in a probabilistic approach. The method allows us to quantify the uncertainty of deep ocean mass fluxes given available d13C observations/reconstructions and provide a quantitative test of the assumption of d13C as a ventilation proxy.

  8. Uncertainties in Modelling Glacier Melt and Mass Balances: the Role of Air Temperature Extrapolation and Type of Melt Models

    NASA Astrophysics Data System (ADS)

    Pellicciotti, F.; Ragettli, S.; Carenzo, M.; Ayala, A.; McPhee, J. P.; Stoffel, M.

    2014-12-01

    While glacier responses to climate are understood in general terms and in their main trends, model based projections are affected by the type of model used and uncertainties in the meteorological input data, among others. Recent works have attempted at improving glacio-hydrological models by including neglected processes and investigating uncertainties in their outputs. In this work, we select two knowledge gaps in current modelling practices and illustrate their importance through modelling with a fully distributed mass balance model that includes some of the state of the art approaches for calculations of glacier ablation, accumulation and glacier geometry changes. We use an advanced mass balance model applied to glaciers in the Andes of Chile, Swiss Alps and Nepalese Himalaya to investigate two issues that seem of importance for a sound assessment of glacier changes: 1) the use of physically-based models of glacier ablation (energy balance) versus more empirical models (enhanced temperature index approaches); 2) the importance of the correct extrapolation of air temperature forcing on glaciers and the large uncertainty in model outputs associated with it. The ablation models are calibrated with a large amount of data from in-situ campaigns, and distributed observations of air temperature used to calculate lapse rates and calibrate a thermodynamic model of temperature distribution. We show that no final assessment can be made of what type of melt model is more appropriate or accurate for simulation of glacier ablation at the glacier scale, not even for relatively well studied glaciers. Both models perform in a similar manner at low elevations, but important differences are evident at high elevations, where lack of data prevents a final statement on which model better represent the actual ablation amounts. Accurate characterization of air temperature is important for correct simulations of glacier mass balance and volume changes. Substantial differences are

  9. Forecasting for New York City and its Surroundings, with Emphasis on Sea-Surface Temperature's Effect on Sea Breezes and Other Coastal Circulations that Influence Air Quality

    NASA Astrophysics Data System (ADS)

    Knievel, J. C.; Rife, D. L.; Grim, J. A.

    2008-12-01

    The complex coastal setting of New York City, Long Island, and the surrounding urban environment affects boundary-layer winds and the way they transport hazardous airborne materials, including pollutants. Properly forecasting coastal circulations, such as sea breezes, is critical if weather-based decision support systems (DSSs) are to be useful to health officials, emergency responders, and anyone else interested in the challenges of predicting transport and dispersion in urban settings. The Research Applications Laboratory (RAL) within the National Center for Atmospheric Research (NCAR) is running a real-time forecast system focused on New York City (NYC) and its urban and suburban surroundings. The system is based on the Weather Research and Forecasting (WRF) Model and NCAR's Real-Time Four-Dimensional Data Assimilation (RTFDDA) System. The presenter will provide an overview of the project and present results from a few case studies of sea breezes and other circulations characteristic of the complex coastal setting of NYC and Long Island. A particular emphasis of the presentation will be the sensitivity of forecasts to sea-surface temperature (SST). The forecast system is currently using SSTs from gridded composites created by NCAR from observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Aqua and Terra satellites.

  10. What is the role of wind pumping on heat and mass transfer rates at the air-snow interface?

    NASA Astrophysics Data System (ADS)

    Helgason, W.; Pomeroy, J. W.

    2010-12-01

    Accurate prediction of the turbulent exchange of sensible heat and water vapour between the atmosphere and snowpack remains a challenging task under all but the most ideal conditions. Heat and mass transfer coefficients that recognize the unique properties of the snow surface are warranted. A particular area requiring improvement concerns the role of the porous nature of snow which provides a large surface area for heat and mass exchange with the atmosphere. Wind-pumping has long been considered as a viable mechanism for incorporating aerosols into snowpacks; however these processes are not considered in parameterization schemes for heat and mass transfer near the surface. This study attempts to determine the degree to which wind pumping can increase the rates of heat and mass transfer to snow, and to ascertain which structural properties of the snowpack are needed for inclusion in heat and mass transfer coefficients that reflect wind pumping processes. Based upon a review of recent geophysical and engineering literature where porous surfaces are exploited for their ability to augment heat and mass transfer rates, a technical analysis was conducted. Numerous conceptual mechanisms of wind pumping were considered: topographically-induced flow; barometric pressure changes; high frequency pressure fluctuations at the surface; and steady flow in the interfacial region. A sensitivity analysis was performed, subjecting each conceptual model to varying thermal and hydraulic conditions at the air-snow interface, as well as variable micro-structural properties of snow. It is shown that the rate of heat and mass exchange is most sensitive to the interfacial thermal conditions and factors controlling the energy balance of the uppermost snow grains. The effect upon the thermal regime of the snowpack was found to be most significant for mechanisms of wind pumping that result in shorter flow paths near the surface, rather than those caused by low frequency pressure changes. In

  11. NEIGHBORHOOD SCALE AIR QUALITY MODELING IN HOUSTON USING URBAN CANOPY PARAMETERS IN MM5 AND CMAQ WITH IMPROVED CHARACTERIZATION OF MESOSCALE LAKE-LAND BREEZE CIRCULATION

    EPA Science Inventory

    Advanced capability of air quality simulation models towards accurate performance at finer scales will be needed for such models to serve as tools for performing exposure and risk assessments in urban areas. It is recognized that the impact of urban features such as street and t...

  12. Seasonal variability of tritium and ion concentrations in rain at Kumamoto, Japan and back-trajectory analysis of air mass

    SciTech Connect

    Momoshima, N.; Sugihara, S.; Toyoshima, T.; Nagao, Y.; Takahashi, M.; Nakamura, Y.

    2008-07-15

    Tritium and major ion concentrations in rain were analyzed in Kumamoto (Japan)) between 2001 and 2006 to examine present tritium concentration and seasonal variation. The average tritium concentration was 0.36 {+-} 0.19 Bq/L (n=104) and higher tritium concentrations were observed in spring than the other seasons. Among the ions, non-sea-salt (nss) SO{sub 4}{sup 2}'- showed higher concentration in winter while other ions did not show marked increase in winter. Based on the back-trajectory analyses of air masses, the increase in tritium concentrations in spring arises from downward movement of naturally produced tritium from stratosphere to troposphere, while the increase of the nss-SO{sub 4}{sup 2-} concentrations in winter is due to long range transport of pollutants from China to Japan. (authors)

  13. Distinct synoptic patterns and air masses responsible for long-range desert dust transport and sea spray in Palermo, Italy

    NASA Astrophysics Data System (ADS)

    Dimitriou, K.; Paschalidou, A. K.; Kassomenos, P. A.

    2016-09-01

    Undoubtedly, anthropogenic emissions carry a large share of the risk posed on public health by particles exposure in urban areas. However, natural emissions, in the form of desert dust and sea spray, are well known to contribute significantly to the PM load recorded in many Mediterranean environments, posing an extra risk burden on public health. In the present paper, we examine the synoptic climatology in a background station in Palermo, Italy, through K-means clustering of the mean sea-level pressure (MSLP) maps, in an attempt to associate distinct synoptic patterns with increased PM10 levels. Four-day backward trajectory analysis is then applied, in order to study the origins and pathways of air masses susceptible of PM10 episodes. It is concluded that a number of atmospheric patterns result in several kind of flows, namely south, west, and slow-moving/stagnant flows, associated with long-range dust transport and sea spray.

  14. Brief Communication: Upper-air relaxation in RACMO2 significantly improves modelled interannual surface mass balance variability in Antarctica

    NASA Astrophysics Data System (ADS)

    van de Berg, Willem Jan; Medley, Brooke

    2016-03-01

    The Regional Atmospheric Climate Model (RACMO2) has been a powerful tool for improving surface mass balance (SMB) estimates from GCMs or reanalyses. However, new yearly SMB observations for West Antarctica show that the modelled interannual variability in SMB is poorly simulated by RACMO2, in contrast to ERA-Interim, which resolves this variability well. In an attempt to remedy RACMO2 performance, we included additional upper-air relaxation (UAR) in RACMO2. With UAR, the correlation to observations is similar for RACMO2 and ERA-Interim. The spatial SMB patterns and ice-sheet-integrated SMB modelled using UAR remain very similar to the estimates of RACMO2 without UAR. We only observe an upstream smoothing of precipitation in regions with very steep topography like the Antarctic Peninsula. We conclude that UAR is a useful improvement for regional climate model simulations, although results in regions with steep topography should be treated with care.

  15. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  16. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean

    USGS Publications Warehouse

    Garrison, Virginia H.; Majewski, Michael S.; Foreman, William T.; Genualdi, Susan A.; Mohammed, Azad; Massey Simonich, Stacy L.

    2014-01-01

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9–126 ng/m3 (mean = 25 ± 34) at source and 0.05–0.71 ng/m3 (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1–3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses.

  17. Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air.

    PubMed

    Urabe, Tatsuya; Takahashi, Kazuya; Kitagawa, Michiko; Sato, Takafumi; Kondo, Tomohide; Enomoto, Shuichi; Kidera, Masanori; Seto, Yasuo

    2014-01-01

    A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future. PMID:24211802

  18. Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air.

    PubMed

    Urabe, Tatsuya; Takahashi, Kazuya; Kitagawa, Michiko; Sato, Takafumi; Kondo, Tomohide; Enomoto, Shuichi; Kidera, Masanori; Seto, Yasuo

    2014-01-01

    A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future.

  19. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean.

    PubMed

    Garrison, V H; Majewski, M S; Foreman, W T; Genualdi, S A; Mohammed, A; Massey Simonich, S L

    2014-01-15

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9-126 ng/m(3) (mean = 25 ± 34) at source and 0.05-0.71 ng/m(3) (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1-3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses. PMID:24055669

  20. A mass balance method for non-intrusive measurements of surface-air trace gas exchange

    NASA Astrophysics Data System (ADS)

    Denmead, O. T.; Harper, L. A.; Freney, J. R.; Griffith, D. W. T.; Leuning, R.; Sharpe, R. R.

    A mass balance method is described for calculating gas production from a surface or volume source in a small test plot from measurements of differences in the horizontal fluxes of the gas across upwind and downwind boundaries. It employs a square plot, 24 m×24 m, with measurements of gas concentration at four heights (up to 3.5 m) along each of the four boundaries. Gas concentrations are multiplied by the appropriate vector winds to yield the horizontal fluxes at each height on each boundary. The difference between these fluxes integrated over downwind and upwind boundaries represents production. Illustrations of the method, which involve exchanges of methane and carbon dioxide, are drawn from experiments with landfills, pastures and grazing animals. Tests included calculation of recovery rates from known gas releases and comparisons with a conventional micrometeorological approach and a backward dispersion model. The method performed satisfactorily in all cases. Its sensitivity for measuring exchanges of CO 2, CH 4 and N 2O in various scenarios was examined. As employed by us, the mass balance method can suffer from errors arising from the large number of gas analyses required for a flux determination, and becomes unreliable when there are light winds and variable wind directions. On the other hand, it is non-disturbing, has a simple theoretical basis, is independent of atmospheric stability or the shape of the wind profile, and is appropriate for flux measurement in situations where conventional micrometeorological methods can not be used, e.g. for small plots, elevated point sources, and heterogeneous surface sources.

  1. Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath.

    PubMed

    Spesyvyi, Anatolii; Smith, David; Španěl, Patrik

    2015-12-15

    A selected ion flow-drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion-molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density), and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O(+) ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O(+) ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O(+) reagent ions with H2O molecules, which is the first step in the production of H3O(+)(H2O)1,2,3 reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates the development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses.

  2. Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath.

    PubMed

    Spesyvyi, Anatolii; Smith, David; Španěl, Patrik

    2015-12-15

    A selected ion flow-drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion-molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density), and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O(+) ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O(+) ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O(+) reagent ions with H2O molecules, which is the first step in the production of H3O(+)(H2O)1,2,3 reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates the development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses. PMID:26583448

  3. Atmospheric pollutants in Chiang Mai (Thailand) over a five-year period (2005-2009), their possible sources and relation to air mass movement

    NASA Astrophysics Data System (ADS)

    Chantara, Somporn; Sillapapiromsuk, Sopittaporn; Wiriya, Wan

    2012-12-01

    Monitoring and analysis of the chemical composition of air pollutants were conducted over a five-year period (2005-2009) in the sub-urban area of Chiang Mai, Thailand. This study aims to determine the seasonal variation of atmospheric ion species and gases, examine their correlations, identify possible sources and assess major air-flow patterns to the receptor. The dominant gas and particulate pollutants were NH3 (43-58%) and SO42- (39-48%), respectively. The annual mean concentrations of NH3 (μg m-3) in descending order were 4.08 (2009) > 3.32 (2007) > 2.68 (2008) > 2.47 (2006) and 1.87 (2005), while those of SO42- (μg m-3) were 2.60 (2007) > 2.20 (2006) > 1.95 (2009) > 1.75 (2008) and 1.26 (2005). Concentrations of particulate ions were analyzed by principle component analysis to find out the possible sources of air pollutants in this area. The first component of each year had a high loading of SO42- and NH4+, which probably came from fuel combustion and agricultural activity, respectively. K+, a tracer of biomass burning, also contributed to the first or the second components of each year. Concentrations of NH4+ and SO42- were well correlated (r > 0.777, p < 0.01), which lead to the conclusion that (NH4)2SO4 was a major compound present in this area. The 3-day backward trajectories of air mass arriving at Chiang Mai from 2005 to 2009 were analyzed using the hybrid single particle langrangian integrated trajectory (HYSPLIT) model and grouped by cluster analysis. The air mass data was analyzed for the dry season (n = 18; 100%). The trajectory of air mass in 2005 mainly originated locally (67%). In 2006, the recorded data showed that 56% of air mass was emitted from the western continental region of Thailand. In 2007, the percent ratios from the western and eastern continental areas were equal (39%). In 2008, 67% originated from the western continental area. In 2009, the recorded air mass mainly came from the western continental area (72%). In conclusion, the

  4. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    PubMed

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC.

  5. Air flow-assisted ionization imaging mass spectrometry method for easy whole-body molecular imaging under ambient conditions.

    PubMed

    Luo, Zhigang; He, Jiuming; Chen, Yi; He, Jingjing; Gong, Tao; Tang, Fei; Wang, Xiaohao; Zhang, Ruiping; Huang, Lan; Zhang, Lianfeng; Lv, Haining; Ma, Shuanggang; Fu, Zhaodi; Chen, Xiaoguang; Yu, Shishan; Abliz, Zeper

    2013-03-01

    Whole-body molecular imaging is able to directly map spatial distribution of molecules and monitor its biotransformation in intact biological tissue sections. Imaging mass spectrometry (IMS), a label-free molecular imaging method, can be used to image multiple molecules in a single measurement with high specificity. Herein, a novel easy-to-implement, whole-body IMS method was developed with air flow-assisted ionization in a desorption electrospray ionization mode. The developed IMS method can effectively image molecules in a large whole-body section in open air without sample pretreatment, such as chemical labeling, section division, or matrix deposition. Moreover, the signal levels were improved, and the spatial assignment errors were eliminated; thus, high-quality whole-body images were obtained. With this novel IMS method, in situ mapping analysis of molecules was performed in adult rat sections with picomolar sensitivity under ambient conditions, and the dynamic information of molecule distribution and its biotransformation was provided to uncover molecular events at the whole-animal level. A global view of the differential distribution of an anticancer agent and its metabolites was simultaneously acquired in whole-body rat and model mouse bearing neuroglioma along the administration time. The obtained drug distribution provided rich information for identifying the targeted organs and predicting possible tumor spectrum, pharmacological activity, and potential toxicity of drug candidates.

  6. Development of analysis of volatile polyfluorinated alkyl substances in indoor air using thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Wu, Yaoxing; Chang, Victor W-C

    2012-05-18

    The study attempts to utilize thermal desorption (TD) coupled with gas chromatography-mass spectrometry (GC-MS) for determination of indoor airborne volatile polyfluorinated alkyl substances (PFASs), including four fluorinated alcohols (FTOHs), two fluorooctane sulfonamides (FOSAs), and two fluorooctane sulfonamidoethanols (FOSEs). Standard stainless steel tubes of Tenax/Carbograph 1 TD were employed for low-volume sampling and exhibited minimal breakthrough of target analytes in sample collection. The method recoveries were in the range of 88-119% for FTOHs, 86-138% for FOSAs, exhibiting significant improvement compared with other existing air sampling methods. However, the widely reported high method recoveries of FOSEs were also observed (139-210%), which was probably due to the structural differences between FOSEs and internal standards. Method detection limit, repeatability, linearity, and accuracy were reported as well. The approach has been successfully applied to routine quantification of targeted PFASs in indoor environment of Singapore. The significantly shorter sampling time enabled the observation of variations of concentrations of targeted PFASs within different periods of a day, with higher concentration levels at night while ventilation systems were shut off. This indicated the existence of indoor sources and the importance of building ventilation and air conditioning system.

  7. Thermally-driven advections of aerosol-rich air masses to an Alpine valley: Theoretical considerations and experimental evidences

    NASA Astrophysics Data System (ADS)

    Diémoz, Henri; Magri, Tiziana; Pession, Giordano; Zublena, Manuela; Campanelli, Monica; Gobbi, Gian Paolo; Barnaba, Francesca; Di Liberto, Luca; Dionisi, Davide

    2016-04-01

    A CHM-15k laser radar (lidar) was installed in April 2015 at the solar observatory of the Environmental Protection Agency (ARPA) of the Aosta Valley (Northern Italy, 45.74N, 7.36E, 560 m a.s.l.). The instrument operates at 1064 nm, is capable of mapping the vertical profile of aerosols and clouds up to the tropopause and is part of the Alice-net ceilometers network (www.alice-net.eu). The site is in a large Alpine valley floor, in a semi-rural context. Among the most interesting cases observed in the first months of operation, several days characterised by weak synoptic circulation and well-developed, thermally-driven up-valley winds are accompanied by the appearance of a thick aerosol layer in the afternoon. The phenomenon is frequent in Spring and Summer and is likely to be related to easterly airmass advections from polluted sites (e.g., the Po basin) rather than to local emissions. To test this hypothesis, the following method was adopted. First, some case studies were selected and the respective meteorological fields were analysed based on both observations at ground and the high-resolution output of the nonhydrostatic limited-area atmospheric prediction model maintained by the COnsortium for Small-scale MOdelling (COSMO) over the complex orography of the domain. Then, to evaluate the dynamics of the aerosol diffusion in the valley, the chemical transport 2D/3D eulerian Flexible Air quality Regional Model (FARM) was run. Finally, the three-dimensional output of the model was compared to the vertically-resolved aerosol field derived from the lidar-ceilometer soundings. The effects of up-slope winds, and the resulting subsidence along the main axis of the valley, is hypothesised to break up the aerosol layer close to the ground in the middle of the day and to drag the residual layer down into the mixing layer. The measurements by a co-located sun/sky photometer operating in the framework of the EuroSkyRad (ESR) network were additionally analysed to detect any

  8. Identification of water-soluble polar organics in air and vehicular emitted particulate matter using ultrahigh resolution mass spectrometry and Capillary electrophoresis - mass spectrometry.

    NASA Astrophysics Data System (ADS)

    Schmitt-Kopplin, P.; Yassine, M.; Gebefugi, I.; Hertkorn, N.; Dabek-Zlotorzynska, E.

    2009-04-01

    The effects of aerosols on human health, atmospheric chemistry, and climate are among the central topics in current environmental health research. Detailed and accurate measurements of the chemical composition of air particulate matter (PM) represent a challenging analytical task. Minute sample amounts are usually composed of several main constituents and hundreds of minor and trace constituents. Moreover, the composition of individual particles can be fairly uniform or very different (internally or externally mixed aerosols), depending on their origin and atmospheric aging processes (coagulation, condensation / evaporation, chemical reaction). The aim of the presentation was the characterization of the organic matter (OM) fraction of environmental aerosols which is not accessible by GC-methods, either because of their high molecular weight, their polarity or due to thermal instability. We also describe the main chemical characteristics of complexe oligomeric organic fraction extracted from different aerosols collected in urban and rural area in Germany and Canada. Mass spectrometry (MS) became an essential tool used by many prominent leaders of the biological research community and the importance of MS to the future of biological research is now clearly evident as in the fields of Proteomics and Metabolomics. Especially Fourier Transform Ion Cyclotron Mass Spectrometry (ICR-FT/MS) is an ultrahigh resolution MS that allows new approach in the analysis of complex mixtures. The mass resolution (< 200 ppb) allowed assigning the elemental composition (C, H, O, N, S…) to each of the obtained mass peaks and thus already a description of the mixture in terms of molecular composition. This possibility is used by the authors together with a high resolution separation method of charged compounds: capillary electrophoresis. A CE-ESI-MS method using an ammonium acetate based background electrolyte (pH 4.7) was developed for the determination of isomeric benzoic acids in

  9. Large-Scale Air Mass Characteristics Observed Over the Remote Tropical Pacific Ocean During March-April 1999: Results from PEM-Tropics B Field Experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Fenn, Marta A.; Butler, Carolyn F.; Grant, William B.; Ismail, Syed; Ferrare, Richard A.; Kooi, Susan A.; Brackett, Vincent G.; Clayton, Marian B.; Avery, Melody A.

    2001-01-01

    Eighteen long-range flights over the Pacific Ocean between 38 S to 20 N and 166 E to 90 W were made by the NASA DC-8 aircraft during the NASA Pacific Exploratory Mission (PEM) Tropics B conducted from March 6 to April 18, 1999. Two lidar systems were flown on the DC-8 to remotely measure vertical profiles of ozone (O3), water vapor (H2O), aerosols, and clouds from near the surface to the upper troposphere along their flight track. In situ measurements of a wide range of gases and aerosols were made on the DC-8 for comprehensive characterization of the air and for correlation with the lidar remote measurements. The transition from northeasterly flow of Northern Hemispheric (NH) air on the northern side of the Intertropical Convergence Zone (ITCZ) to generally easterly flow of Southern Hemispheric (SH) air south of the ITCZ was accompanied by a significant decrease in O3, carbon monoxide, hydrocarbons, and aerosols and an increase in H2O. Trajectory analyses indicate that air north of the ITCZ came from Asia and/or the United States, while the air south of the ITCZ had a long residence time over the Pacific, perhaps originating over South America several weeks earlier. Air south of the South Pacific Convergence Zone (SPCZ) came rapidly from the west originating over Australia or Africa. This air had enhanced O3 and aerosols and an associated decrease in H2O. Average latitudinal and longitudinal distributions of O3 and H2O were constructed from the remote and in situ O3 and H2O data, and these distributions are compared with results from PEM-Tropics A conducted in August-October 1996. During PEM-Tropics B, low O3 air was found in the SH across the entire Pacific Basin at low latitudes. This was in strong contrast to the photochemically enhanced O3 levels found across the central and eastern Pacific low latitudes during PEM-Tropics A. Nine air mass types were identified for PEM-Tropics B based on their O3, aerosols, clouds, and potential vorticity characteristics. The

  10. The influence of air temperature inversions on snowmelt and glacier mass-balance simulations, Ammassalik island, SE Greenland

    SciTech Connect

    Mernild, Sebastian Haugard; Liston, Glen

    2009-01-01

    In many applications, a realistic description of air temperature inversions is essential for accurate snow and glacier ice melt, and glacier mass-balance simulations. A physically based snow-evolution modeling system (SnowModel) was used to simulate eight years (1998/99 to 2005/06) of snow accumulation and snow and glacier ice ablation from numerous small coastal marginal glaciers on the SW-part of Ammassalik Island in SE Greenland. These glaciers are regularly influenced by inversions and sea breezes associated with the adjacent relatively low temperature and frequently ice-choked fjords and ocean. To account for the influence of these inversions on the spatiotemporal variation of air temperature and snow and glacier melt rates, temperature inversion routines were added to MircoMet, the meteorological distribution sub-model used in SnowModel. The inversions were observed and modeled to occur during 84% of the simulation period. Modeled inversions were defined not to occur during days with strong winds and high precipitation rates due to the potential of inversion break-up. Field observations showed inversions to extend from sea level to approximately 300 m a.s.l., and this inversion level was prescribed in the model simulations. Simulations with and without the inversion routines were compared. The inversion model produced air temperature distributions with warmer lower elevation areas and cooler higher elevation areas than without inversion routines due to the use of cold sea-breeze base temperature data from underneath the inversion. This yielded an up to 2 weeks earlier snowmelt in the lower areas and up to 1 to 3 weeks later snowmelt in the higher elevation areas of the simulation domain. Averaged mean annual modeled surface mass-balance for all glaciers (mainly located above the inversion layer) was -720 {+-} 620 mm w.eq. y{sup -1} for inversion simulations, and -880 {+-} 620 mm w.eq. y{sup -1} without the inversion routines, a difference of 160 mm w.eq. y

  11. Long-term measurements of particle number size distributions and the relationships with air mass history and source apportionment in the summer of Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Hu, M.; Wu, Z. J.; Yue, D. L.; He, L. Y.; Huang, X. F.; Liu, X. G.; Wiedensohler, A.

    2013-02-01

    A series of long-term and temporary measurements were conducted to study the improvement of air quality in Beijing during Olympic Games period (8-24 August 2008). To evaluate actions taken to improve the air quality, comparisons of particle number and volume size distributions of August 2008 and 2004-2007 were performed. The total particle number and volume concentrations were 14 000 cm-3 and 37 μm3 cm-3 in August of 2008, respectively. These were reductions of 41% and 35% compared with the mean values of August 2004-2007. A cluster analysis on air mass history and source apportionment were performed, exploring reasons of the reduction of particle concentrations. Back trajectories were classified into five major clusters. Air mass from south direction are always associated with pollution events during the summertime of Beijing. In August 2008, the frequency of air mass arriving from south has been twice higher compared to the average of the previous years, these southerly air masses did however not result in elevated particle volume concentrations in Beijing. This result implied that the air mass history was not the key factor, explaining reduced particle number and volume concentrations during the Beijing 2008 Olympic Games. Four factors were found influencing particle concentrations using a Positive matrix factorization (PMF) model. They were identified to local and remote traffic emissions, combustion sources as well as secondary transformation. The reductions of the four sources were calculated to 47%, 44%, 43% and 30%, respectively. The significant reductions of particle number and volume concentrations may attribute to actions taken, focusing on primary emissions, especially related to the traffic and combustion sources.

  12. First day of an oil spill on the open sea: early mass transfers of hydrocarbons to air and water.

    PubMed

    Gros, Jonas; Nabi, Deedar; Würz, Birgit; Wick, Lukas Y; Brussaard, Corina P D; Huisman, Johannes; van der Meer, Jan R; Reddy, Christopher M; Arey, J Samuel

    2014-08-19

    During the first hours after release of petroleum at sea, crude oil hydrocarbons partition rapidly into air and water. However, limited information is available about very early evaporation and dissolution processes. We report on the composition of the oil slick during the first day after a permitted, unrestrained 4.3 m(3) oil release conducted on the North Sea. Rapid mass transfers of volatile and soluble hydrocarbons were observed, with >50% of ≤C17 hydrocarbons disappearing within 25 h from this oil slick of <10 km(2) area and <10 μm thickness. For oil sheen, >50% losses of ≤C16 hydrocarbons were observed after 1 h. We developed a mass transfer model to describe the evolution of oil slick chemical composition and water column hydrocarbon concentrations. The model was parametrized based on environmental conditions and hydrocarbon partitioning properties estimated from comprehensive two-dimensional gas chromatography (GC×GC) retention data. The model correctly predicted the observed fractionation of petroleum hydrocarbons in the oil slick resulting from evaporation and dissolution. This is the first report on the broad-spectrum compositional changes in oil during the first day of a spill at the sea surface. Expected outcomes under other environmental conditions are discussed, as well as comparisons to other models.

  13. Cyclic organic peroxides identification and trace analysis by Raman microscopy and open-air chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pena-Quevedo, Alvaro Javier

    The persistent use of cyclic organic peroxides in explosive devices has increased the interest in study these compounds. Development of methodologies for the detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has become an urgent priority. However, differences in physical properties between cyclic organic peroxides make difficult the development of a general method for peroxide analysis and detection. Following this urgency, the first general technique for the analysis of any peroxide, regarding its structural differences is reported. Characterization and detection of TATP and HMTD was performed using an Open-Air Chemical Ionization High-Resolution Time-of-Flight Mass Spectrometer. The first spectrometric analysis for tetramethylene diperoxide dicarbamide (TMDD) and other nitrogen based peroxides using Raman Microscopy and Mass Spectrometry is reported. Analysis of cyclic peroxides by GC-MS was also conducted to compare results with OACI-HRTOF data. In the OACI mass spectrum, HMTD showed a clear signal at m/z 209 MH + and a small adduct peak at m/z 226 [M+NH4]+ that allowed its detection in commercial standard solutions and lab made standards. TMDD presented a molecular peak of m/z 237 MH+ and an adduct peak of m/z 254 [M+NH4]+. TATP showed a single peak at m/z 240 [M+NH4]+, while the peak of m/z 223 or 222 was completely absent. This evidence suggests that triperoxides are stabilized by the ammonium ion. TATP samples with deuterium enrichment were analyzed to compare results that could differentiate from HMTD. Raman microscopy was used as a complementary characterization method and was an essential tool for cyclic peroxides identification, particularly for those which could not be extensively purified. All samples were characterized by Raman spectroscopy to confirm the Mass Spectrometry results. Peroxide O-O vibrations were observed around 750-970 cm-1. D18-TATP studies had identified ketone triperoxide nu(O-O) vibration around

  14. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  15. Physical and chemical processes of air masses in the Aegean Sea during Etesians: Aegean-GAME airborne campaign.

    PubMed

    Tombrou, M; Bossioli, E; Kalogiros, J; Allan, J D; Bacak, A; Biskos, G; Coe, H; Dandou, A; Kouvarakis, G; Mihalopoulos, N; Percival, C J; Protonotariou, A P; Szabó-Takács, B

    2015-02-15

    High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 ± 76 ppbv for CO, 62.5 ± 4.1 ppbv for O3, 5.0 ± 1.1 μg m(-3) for sulfate, 4.7 ± 0.9 μg m(-3) for organic mass and 0.5 ± 0.2 μg m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport. PMID:25460953

  16. On-line analysis of volatile chlorinated hydrocarbons in air by gas chromatography-mass spectrometry Improvements in preconcentration and injection steps.

    PubMed

    Zoccolillo, Lelio; Amendola, Luca; Insogna, Susanna; Pastorini, Elisabetta

    2010-06-11

    An analytical system composed of a cryofocusing trap injector device coupled to a gas chromatograph with mass spectrometric detection (CTI-GC-MS) specific for the on-line analysis in air of volatile chlorinated hydrocarbons (VCHCs) (dichloromethane; chloroform; 1,1,1-trichloroethane; tetrachloromethane; 1,1,2-trichloroethylene; tetrachloroethylene) was developed. The cryofocusing trap injector was the result of appropriate low cost modifications to an original purge-and-trap device to make it suitable for direct air analysis even in the case of only slightly contaminated air samples, such as those from remote zones. The CTI device can rapidly and easily be rearranged into the purge-and-trap allowing water and air analysis with the same apparatus. Air samples, collected in stainless steel canisters, were introduced directly into the CTI-GC-MS system to realize cryo-concentration (at -120 degrees C), thermal desorption (at 200 degrees C) and for the subsequent analysis of volatiles. The operating phases and conditions were customised and optimized. Recovery efficiency was optimized in terms of moisture removal, cold trap temperature and sampling mass flow. The injection of entrapped volatiles was realized through a direct transfer with high chromatographic reliability (capillary column-capillary column). These improvements allowed obtaining limits of detection (LODs) at least one order of magnitude lower than current LODs for the investigated substances. The method was successfully employed on real samples: air from urban and rural areas and air from remote zones such as Antarctica.

  17. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  18. Linear thermal circulator based on Coriolis forces.

    PubMed

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform.

  19. Impact of Stratospheric Ozone Distribution on Features of Tropospheric Circulation

    NASA Astrophysics Data System (ADS)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2016-04-01

    In this work we study connections between stratospheric ozone distribution and general circulation patterns in the troposphere and aim to investigate the causal relationship between them, including the practical side of the influence of stratospheric ozone on tropospheric medium-range weather and regional climate. Analysis of several decades of observational data, which has been performed at the A.I. Voeikov Main Geophysical Observatory, suggests a clear relation between the stratospheric ozone distribution, upper stratospheric temperature field and planetary-scale air-masses boundaries in the troposphere [1]. Furthermore, it has been shown that each global air-mass, which can be attributed to the corresponding circulation cell in a conceptual model of tropospheric general circulation, has a distinct "regime" of ozone vertical distribution in the stratosphere [1-3]. Proceeding from atmospheric reanalyses combined with satellite and ground-based observations, we study time evolution of the upper-level frontal zones (stationary fronts) with the relevant jet streams, which can be treated as boundaries of global air-masses, in connection with the tropopause height and distribution of ozone in the stratosphere. For that, we develop an algorithm for automated identification of jet streams, stationary fronts and tropopause surface from gridded data (reanalyses or modelling results), and apply it for several cases associated with rapid changes in the stratospheric temperature and ozone fields, including SSW events over Eastern Siberia. Aiming to study the causal relationship between the features of tropospheric circulation and changes in the stratospheric ozone field, we estimate the time lag between these categories of processes on different time scales. Finally, we discuss the possibility to use the elementary circulation mechanisms classification (by B.L. Dzerdzeevski) in connection with analysis of the stratospheric ozone field and the relevant stratosphere

  20. Hydrogen sulphide in human nasal air quantified using thermal desorption and selected ion flow tube mass spectrometry.

    PubMed

    Wondimu, Taddese; Wang, Rui; Ross, Brian

    2014-09-01

    The discovery that hydrogen sulphide (H2S) acts as a gasotransmitter when present at very low concentrations (sub-parts per billion (ppbv)) has resulted in the need to quickly quantify trace amounts of the gas in complex biological samples. Selected ion flow tube mass spectrometry (SIFT-MS) is capable of real-time quantification of H2S but many SIFT-MS instruments lack sufficient sensitivity for this application. In this study we investigate the utility of combining thermal desorption with SIFT-MS for quantifying H2S in the 0.1-1 ppbv concentration range. Human orally or nasally derived breath, and background ambient air, were collected in sampling bags and dried by passing through CaCl2 and H2S pre-concentrated using a sorbent trap optimised for the capture of this gas. The absorbed H2S was then thermally desorbed and quantified by SIFT-MS. H2S concentrations in ambient air, nasal breath and oral breath collected from 10 healthy volunteers were 0.12  ±  0.02 (mean ± SD), 0.40  ±  0.11 and 3.1  ±  2.5 ppbv respectively, and in the oral cavity H2S, quantified by SIFT-MS without pre-concentration, was present at 13.5  ±  8.6 ppbv. The oral cavity H2S correlates well with oral breath H2S but not with nasal breath H2S, suggesting that oral breath H2S derives mainly from the oral cavity but nasal breath is likely pulmonary in origin. The successful quantification of such low concentrations of H2S in nasal air using a rapid analytical procedure paves the way for the straightforward analysis of H2S in breath and may assist in elucidating the role that H2S plays in biological systems.

  1. Automated high-speed analysis of selected organic compounds in urban air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry.

    PubMed

    Davoli, E; Cappellini, L; Maggi, M; Fanelli, R

    1994-11-01

    An automated environmental air monitor has been developed to measure selected organic compounds in urban air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous air monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer.The gas chromatograph is equipped with a computer-controlled six-way sampling valve, with a 100-mL sampling loop and thermal desorption cold trap injector. Environmental air is enriched with an isotopically labeled internal standard in the sampling line. This internal standard is added with a validated, custom-made, permeation tube device. The "on-line" internal standard provides for high quality quantitative data because all variations in instrument sensitivity in cryofocusing or in thermal desorption efficiency are taken into account. High repetition rates (down to 5 min for a full analytical cycle) are obtained with the use of an isothermal gas chromatography program, microbore capillary column, and environmental air sampling during the gas chromatography run.

  2. Influence of air mass origin on the wet deposition of nitrogen to Tampa Bay, Florida—An eight-year study

    NASA Astrophysics Data System (ADS)

    Strayer, Hillary; Smith, Ronald; Mizak, Connie; Poor, Noreen

    Rainfall delivers on the average ˜10% of the total annual nitrogen load directly to Tampa Bay, based on precipitation monitoring at a National Atmospheric Deposition Program (NADP) Atmospheric Integrated Research Monitoring Network (AIRMoN) site located adjacent to Tampa Bay in urban Tampa. We coupled the chemical analyses for 606 daily precipitation samples collected from 1996 to 2004 with corresponding air mass trajectory information to investigate if wet-deposited nitrogen originated from near versus removed source regions. Air mass trajectories were obtained using the National Oceanic and Atmospheric Administration (NOAA) HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, and were classified into six trajectory categories by the direction of their approach to Tampa Bay. Rainfall nitrate and ammonium concentrations were significantly lower for over-water air mass trajectories than for over-land trajectories as expected, but contributed to 40% of the total wet-deposited nitrogen, a likely consequence of the higher frequency of rain events for these trajectories. Average rainfall nitrate concentrations were significantly higher for air masses that stagnated over the urbanized bay region. We estimated that local sources contributed 1kgNha-1yr-1 or 25% of the total inorganic nitrogen wet-deposited to Tampa Bay.

  3. REAL TIME, ON-LINE CHARACTERIZATION OF DIESEL GENERATOR AIR TOXIC EMISSIONS BY RESONANCE ENHANCED MULTI-PHOTON IONIZATION TIME OF FLIGHT MASS SPECTROMETRY

    EPA Science Inventory

    The laser based resonance, enhanced multi-photon ionization time-of-flight mass spectrometry (REMPI-TOFMS) technique has been applied to the exhaust gas stream of a diesel generator to measure, in real time, concentration levels of aromatic air toxics. Volatile organic compounds ...

  4. Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

    ERIC Educational Resources Information Center

    Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

    2011-01-01

    Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

  5. Formic and Acetic Acid Observations over Colorado by Chemical Ionization Mass Spectrometry and Organic Acids' Role in Air Quality

    NASA Astrophysics Data System (ADS)

    Treadaway, V.; O'Sullivan, D. W.; Heikes, B.; Silwal, I.; McNeill, A.

    2015-12-01

    Formic acid (HFo) and acetic acid (HAc) have both natural and anthropogenic sources and a role in the atmospheric processing of carbon. These organic acids also have an increasing importance in setting the acidity of rain and snow as precipitation nitrate and sulfate concentrations have decreased. Primary emissions for both organic acids include biomass burning, agriculture, and motor vehicle emissions. Secondary production is also a substantial source for both acids especially from biogenic precursors, secondary organic aerosols (SOAs), and photochemical production from volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). Chemical transport models underestimate organic acid concentrations and recent research has sought to develop additional production mechanisms. Here we report HFo and HAc measurements during two campaigns over Colorado using the peroxide chemical ionization mass spectrometer (PCIMS). Iodide clusters of both HFo and HAc were recorded at mass-to-charge ratios of 173 and 187, respectively. The PCIMS was flown aboard the NCAR Gulfstream-V platform during the Deep Convective Clouds and Chemistry Experiment (DC3) and aboard the NCAR C-130 during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE). The DC3 observations were made in May and June 2012 extending from the surface to 13 km over the central and eastern United States. FRAPPE observations were made in July and August 2014 from the surface to 7 km over Colorado. DC3 measurements reported here are focused over the Colorado Front Range and complement the FRAPPE observations. DC3 HFo altitude profiles are characterized by a decrease up to 6 km followed by an increase either back to boundary layer mixing ratio values or higher (a "C" shape). Organic acid measurements from both campaigns are interpreted with an emphasis on emission sources (both natural and anthropogenic) over Colorado and in situ photochemical production especially ozone precursors.

  6. Determination of trichloroanisole and trichlorophenol in wineries' ambient air by passive sampling and thermal desorption-gas chromatography coupled to tandem mass spectrometry.

    PubMed

    Camino-Sánchez, F J; Bermúdez-Peinado, R; Zafra-Gómez, A; Ruíz-García, J; Vílchez-Quero, J L

    2015-02-01

    The present paper describes the calibration of selected passive samplers used in the quantitation of trichlorophenol and trichloroanisole in wineries' ambient air, by calculating the corresponding sampling rates. The method is based on passive sampling with sorbent tubes and involves thermal desorption-gas chromatography-triple quadrupole mass spectrometry analysis. Three commercially available sorbents were tested using sampling cartridges with a radial design instead of axial ones. The best results were found for Tenax TA™. Sampling rates (R-values) for the selected sorbents were determined. Passive sampling was also used for accurately determining the amount of compounds present in the air. Adequate correlation coefficients between the mass of the target analytes and exposure time were obtained. The proposed validated method is a useful tool for the early detection of trichloroanisole and its precursor trichlorophenol in wineries' ambient air while avoiding contamination of wine or winery facilities.

  7. Transport Regimes of Air Masses Affecting the Tropospheric Composition of the Canadian and European Arctic During RACEPAC 2014 and NETCARE 2014/2015

    NASA Astrophysics Data System (ADS)

    Bozem, H.; Hoor, P. M.; Koellner, F.; Kunkel, D.; Schneider, J.; Schulz, C.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Willis, M. D.; Burkart, J.; Thomas, J. L.; Abbatt, J.

    2015-12-01

    The Arctic is warming much faster than any other place in the world and undergoes a rapid change dominated by a changing climate in this region. The impact of polluted air masses traveling to the Arctic from various remote sources significantly contributes to the observed climate change, in contrast there are additional local emission sources contributing to the level of pollutants (trace gases and aerosol). Processes affecting the emission and transport of these pollutants are not well understood and need to be further investigated. We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories we analyze the transport regimes prevalent during spring (RACEPAC 2014 and NETCARE 2015) and summer (NETCARE 2014) in the observed region. Whereas the eastern part of the Canadian Arctic is affected by air masses with their origin in Asia, in the central and western parts of the Canadian and European Arctic air masses from North America are predominant at the time of the measurement. In general the more northern parts of the Arctic were relatively unaffected by pollution from mid-latitudes since air masses mostly travel within the polar dome, being quite isolated. Associated mixing ratios of CO and CO2 fit into the seasonal cycle observed at NOAA ground stations throughout the Arctic, but show a more mid-latitudinal characteristic at higher altitudes. The transition is remarkably sharp and allows for a chemical definition of the polar dome. At low altitudes, synoptic disturbances transport polluted air masses from mid-latitudes into regions of the polar dome. These air masses contribute to the Arctic pollution background, but also

  8. Development and characterisation of a state-of-the-art GOME-2 formaldehyde air-mass factor algorithm

    NASA Astrophysics Data System (ADS)

    Hewson, W.; Barkley, M. P.; Gonzalez Abad, G.; Bösch, H.; Kurosu, T.; Spurr, R.

    2015-01-01

    Space-borne observations of formaldehyde (HCHO) are frequently used to derive surface emissions of isoprene, an important biogenic volatile organic compound. The conversion of retrieved HCHO slant column concentrations from satellite line of sight measurements to vertical columns is determined through application of an air mass factor (AMF), accounting for instrument viewing geometry, radiative transfer, and vertical profile of the absorber in the atmosphere. This step in the trace gas retrieval is subject to large errors. This work presents the AMF algorithm in use at the University of Leicester (UoL), which introduces scene specific variables into a per-observation full radiative transfer AMF calculation, including increasing spatial resolution of key environmental parameter databases, input variable area weighting, instrument specific scattering weight calculation, and inclusion of an ozone vertical profile climatology. Application of these updates to HCHO slant columns from the GOME-2 instrument is shown to typically adjust the AMF by ±10%, compared to a~reference algorithm without these advanced parameterisations. Furthermore, the new UoL algorithm also incorporates a full radiative transfer error calculation for each scene to help characterise AMF uncertainties. Global median AMF errors are typically 50-60%, and are dominated by uncertainties in the HCHO profile shape and its corresponding seasonal variation.

  9. Student understanding of the volume, mass, and pressure of air within a sealed syringe in different states of compression

    NASA Astrophysics Data System (ADS)

    de Berg, Kevin Charles

    Problem-solving strategies in the physical sciences have been characterized by a dependence on algorithmic techniques often devoid of any reasoning skills. The purpose of this study was to examine student responses to a task relating to Boyle's Law for gases, which did not demand the use of a mathematical equation for its solution. Students (17- to 18-year-olds) in lower sixth form from two colleges in the Leeds district of Yorkshire in England were asked to respond to a task relating to pressure and volume measurements of air within a sealed syringe in different states of compression. Both qualitative and quantitative tasks for the sealed syringe system were examined. It was found that 34% to 38% of students did not understand the concepts of volume and mass, respectively, of a gas under such circumstances. Performance on an inverse ratio (2:1) task was shown to depend on gender and those students who performed well on the 2:1 inverse ratio task did not necessarily perform well on a different inverse ratio task when an arithmetic averaging principle was present. Tasks which draw upon qualitative knowledge as well as quantitative knowledge have the potential to reduce dependence on algorithms, particularly equation substitution and solution. The implications for instructional design are discussed.Received: 14 April 1993; Revised: 29 June 1994;

  10. Volatile garlic odor components: gas phases and adsorbed exhaled air analysed by headspace gas chromatography-mass spectrometry.

    PubMed

    Laakso, I; Seppänen-Laakso, T; Hiltunen, R; Müller, B; Jansen, H; Knobloch, K

    1989-06-01

    Combined headspace gas chromatography-mass spectrometry (HSGC-MS) was used in the analysis of garlic volatile compounds. Twenty major components were identified in the gas phases enriched by fresh, sliced garlic cloves ( ALLIUM SATIVUM L, Allioceae, Liliidae). Suspended dry garlic powder and crushed garlic, incubated in vegetable oil, revealed a different pattern since mainly the amounts of di- and trisulfides were decreased. The considerable compositional differences found in the analyses for the gas phase of garlic cloves, kept in oil, are likely associated with the poor stability of allicin in a lipophilic environment; a marked increase in the amounts of 2-propene-1-thiol, acetic acid, and ethanol was observed in the gas phase, whereas trisulfides were present in traces only. The occurrence of 2-propene-1-thiol and diallyl disulfide, the two principal sulfur components in exhaled air, also may indicate a rapid degradation of most garlic volatile components probably caused by the enzymatically active human salivary or digestive system. PMID:17262412

  11. Long-range transport and re-circulation of pollutants in the western Mediterranean during the project Regional Cycles of Air Pollution in the West-Central Mediterranean Area

    NASA Astrophysics Data System (ADS)

    Gangoiti, Gotzon; Millán, Millán M.; Salvador, Rosa; Mantilla, Enrique

    During the warm season (March-September), high ozone concentrations have been reported at the coastal and mountain monitoring stations of the eastern Iberia coast (Millán et al., J. Geophys. Res. 102 (D7) 8811, J. Appl. Meteorol. 4 (2000) 487). The vegetation protection threshold of current Directive 92/72/EEC and the World Health Organisation guideline for the protection of crops and semi-natural vegetation are systematically exceeded during the whole period. The main objective of the present study is to search for the origin of these chronic pollution levels: to search for the reason(s) for such high O 3 concentrations during such a long period. A mesoscale model is used to reproduce the diurnal cycle of winds and stability/layering over the Western Mediterranean Basin (WMB), at a sufficient space/temporal resolution, under a typical recursive synoptic condition during the warm season: data from the flight tracks of the European Project—Regional Cycles of Air Pollution in the West-Central Mediterranean Area—are used to substantiate the model results. Times of residence and the final distribution of pollutants entering the WMB are estimated using single-particle Lagrangian trajectories and a multiple-particle dispersion model. Our results show that the marine boundary layer and the lower troposphere in the region between the Balearic Islands and eastern Iberia are subject to a flow regime that tends to accumulate pollutants within large circulations, covering the entire western basin. We have also shown a diurnal pulsation of the Tramontana/Mistral wind regime, which can transport new pollutants into the area (background concentrations of 50-65 ppb of O 3 of continental European origin) that are added to local emissions and re-circulated within the coastal breezes at eastern Iberia for periods of more than five days. Local emissions and wind configuration contribute to increase the O 3 concentrations up to 100 ppb and even more.

  12. Inventory of metal complexes circulating in plant fluids: a reliable method based on HPLC coupled with dual elemental and high-resolution molecular mass spectrometric detection.

    PubMed

    Flis, Paulina; Ouerdane, Laurent; Grillet, Louis; Curie, Catherine; Mari, Stéphane; Lobinski, Ryszard

    2016-08-01

    Description of metal species in plant fluids such as xylem, phloem or related saps remains a complex challenge usually addressed either by liquid chromatography-mass spectrometry, X-ray analysis or computational prediction. To date, none of these techniques has achieved a complete and true picture of metal-containing species in plant fluids, especially for the least concentrated complexes. Here, we present a generic analytical methodology for a large-scale (> 10 metals, > 50 metal complexes) detection, identification and semiquantitative determination of metal complexes in the xylem and embryo sac liquid of the green pea, Pisum sativum. The procedure is based on direct injection using hydrophilic interaction chromatography with dual detection by elemental (inductively coupled plasma mass spectrometry) and molecular (high-resolution electrospray mass spectrometry) mass spectrometric detection. Numerous and novel complexes of iron(II), iron(III), copper(II), zinc, manganese, cobalt(II), cobalt(III), magnesium, calcium, nickel and molybdenum(IV) with several ligands including nicotianamine, citrate, malate, histidine, glutamine, aspartic acid, asparagine, phenylalanine and others are observed in pea fluids and discussed. This methodology provides a large inventory of various types of metal complexes, which is a significant asset for future biochemical and genetic studies into metal transport/homeostasis.

  13. Inventory of metal complexes circulating in plant fluids: a reliable method based on HPLC coupled with dual elemental and high-resolution molecular mass spectrometric detection.

    PubMed

    Flis, Paulina; Ouerdane, Laurent; Grillet, Louis; Curie, Catherine; Mari, Stéphane; Lobinski, Ryszard

    2016-08-01

    Description of metal species in plant fluids such as xylem, phloem or related saps remains a complex challenge usually addressed either by liquid chromatography-mass spectrometry, X-ray analysis or computational prediction. To date, none of these techniques has achieved a complete and true picture of metal-containing species in plant fluids, especially for the least concentrated complexes. Here, we present a generic analytical methodology for a large-scale (> 10 metals, > 50 metal complexes) detection, identification and semiquantitative determination of metal complexes in the xylem and embryo sac liquid of the green pea, Pisum sativum. The procedure is based on direct injection using hydrophilic interaction chromatography with dual detection by elemental (inductively coupled plasma mass spectrometry) and molecular (high-resolution electrospray mass spectrometry) mass spectrometric detection. Numerous and novel complexes of iron(II), iron(III), copper(II), zinc, manganese, cobalt(II), cobalt(III), magnesium, calcium, nickel and molybdenum(IV) with several ligands including nicotianamine, citrate, malate, histidine, glutamine, aspartic acid, asparagine, phenylalanine and others are observed in pea fluids and discussed. This methodology provides a large inventory of various types of metal complexes, which is a significant asset for future biochemical and genetic studies into metal transport/homeostasis. PMID:27111838

  14. Direct Lipido-Metabolomics of Single Floating Cells for Analysis of Circulating Tumor Cells by Live Single-cell Mass Spectrometry.

    PubMed

    Hiyama, Eiso; Ali, Ahmed; Amer, Sara; Harada, Takanori; Shimamoto, Kazumi; Furushima, Rie; Abouleila, Yasmine; Emara, Samy; Masujima, Tsutomu

    2015-01-01

    Direct trapping of a single floating cell, i.e. a white blood cell from a drop of blood, within a nanospray tip was followed by super-sonication after the addition of ionization solvent. Molecular detection of an increased number of peaks with a higher intensity and a wider m/z range, which extends from metabolites to lipids, was acquired than of that without sonication. This method was applied to a few separated circulating tumor cells (CTC) from a neuroblastoma patient's blood to obtain their lipido-metabolomic molecular profile at the single cell level. In addition to vital molecules such as amino acids, catechol amine metabolites, which are specific to neuroblastoma, and drugs included in the patient's course of therapy were detected. This established "direct single-cell lipido-metabolomic method" seems to be useful for direct and wide range molecular detection not only for many live single-cells, but also for rare cells, such as CTCs, for future molecular diagnosis.

  15. Equatorial zonal circulations: Historical perspectives

    NASA Astrophysics Data System (ADS)

    Hastenrath, Stefan

    2007-04-01

    The changing perceptions on zonal circulations in the equatorial belt are traced for (a) stratospheric wind regimes, and (b) vertical-zonal circulation cells in the troposphere. (a) Observations from the Krakatoa eruption 1883 and Berson's 1908 expedition to East Africa, along with later soundings over Batavia (Jakarta) led to the notion of "Krakatoa easterlies" around 30 km (10 mb) and "Berson westerlies" around 20 km (50 mb). Prompted by contrary observations since the late 1950s, this dogma was replaced by the notion of easterlies alternating with westerlies in the equatorial stratosphere at a rhythm of about 26 months. (b) Stimulated by Bjerknes' postulate of a "Walker circulation" along the Pacific Equator, a multitude of such cells have been hypothesized at other longitudes, in part from zonal contrasts of temperature and cloudiness. Essential for the diagnosis of equatorial zonal circulation cells is the continuity following the flow between the centers of ascending and subsiding motion. Evaluation of the recent NCEP-NCAR and ECMWF Reanalysis upper-air datasets reveals equatorial zonal circulation cells over the Pacific all year round, over the Atlantic only in boreal winter, and over the Indian Ocean only in autumn, all being seasons and oceanic longitudes with strong zonal flow in the lower troposphere.

  16. Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001(PNW2001) Air Quality Study In Puget Sound

    NASA Astrophysics Data System (ADS)

    Disselkamp, R. S.; Barrie, L. A.; Shutthanadan, S.; Cliff, S.; Cahill, T.

    2001-12-01

    In mid-August, 2001, an aircraft-based air-quality study was performed in the Puget Sound, WA, area entitled PNW2001 (http://www.pnl.gov/pnw2001). The objectives of this field campaign were the following: 1. reveal information about the 3-dimensional distribution of ozone, its gaseous precursors and fine particulate matter during weather conditions favoring air pollution; 2. derive information about the accuracy of urban and biogenic emissions inventories that are used to drive the air quality forecast models; and 3. examine the accuracy of modeled ozone concentration with that observed. In support of these efforts, we collected time-averaged ( { ~}10 minute averages), size-segregated, aerosol composition and mass-loading information using ex post facto analysis techniques of synchrotron x-ray fluorescence (s-XRF), proton induced x-ray emissions(PIXE), proton elastic scattering (PESA), and scanning transmission ion microscopy (STIM). This is the first time these analysis techniques have been used together on samples collected from aircraft using an optimized 3-stage rotating drum impactor. In our presentation, we will discuss the aerosol components in three aerosol size fractions as identified by statistical analysis of multielemental data (including total mass, H, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Pb) and relate variations in these components to physical aerosol properties, other gaseous trace constituents and to air mass origin.

  17. Characterization of ion processes in a GC/DMS air quality monitor by integration of the instrument to a mass spectrometer.

    PubMed

    Limero, T F; Nazarov, E G; Menlyadiev, M; Eiceman, G A

    2015-02-01

    The air quality monitor (AQM), which included a portable gas chromatograph (GC) and a detector was interfaced to a mass spectrometer (MS) by introducing flow from the GC detector to the atmospheric pressure ion source of the MS. This small GC system, with a gas recirculation loop for carrier and detector make-up gases, comprised an inlet to preconcentrate volatile organic compounds (VOCs) in air, a thermal desorber before the GC column, a differential mobility spectrometer (DMS), and another DMS as an atmospheric pressure ionization source for the MS. Return flow to the internally recirculated air system of the AQM's DMS was replenished using purified air. Although ions and unreacted neutral vapors flowed from the detector through Viton® tubing into the source of the MS, ions were not detected in the MS without the auxillary ion source, (63)Ni as in the mobility detector. The GC-DMS-MS instrument provided a 3-D measurement platform (GC, DMS, and MS analysis) to explore the gas composition inside the GC-DMS recirculation loop and provide DMS-MS measurement of the components of a complex VOC mixture with performance significantly enhanced by mass-analysis, either with mass spectral scans or with an extracted ion chromatogram. This combination of a mobility spectrometer and a mass spectrometer was possible as vapors and ions are carried together through the DMS analyzer, thereby preserving the chromatographic separation efficiency. The critical benefit of this instrument concept is that all flows in and through the thoroughly integrated GC-DMS analyzer are kept intact allowing a full measure of the ion and vapor composition in the complete system. Performance has been evaluated using a synthetic air sample and a sample of airborne vapors in a laboratory. Capabilities and performance values are described using results from AQM-MS analysis of purified air, ambient air from a research laboratory in a chemistry building, and a sample of synthetic air of known composition

  18. Air conditioned suit

    NASA Technical Reports Server (NTRS)

    Carl, G. R. (Inventor)

    1973-01-01

    An environmentally controlled suit is described consisting of an airtight outergarment attached by an airtight bellows to the wall of a sterile chamber, an undergarment providing for circulation of air near the skin of the wearer, and a circulation system comprised of air supply and distribution to the extremities of the undegarment and central collection and exhaust of air from the midsection of the undergarment. A workman wearing the undergarment and attached circulation system enters the outer garment through a tunnel in the chamber wall and the attached bellows to work in the chamber without any danger of spreading bacteria.

  19. Oxy-combustion of biomass in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Kosowska-Golachowska, Monika; Kijo-Kleczkowska, Agnieszka; Luckos, Adam; Wolski, Krzysztof; Musiał, Tomasz

    2016-03-01

    The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  20. Development and characterisation of a state-of-the-art GOME-2 formaldehyde air-mass factor algorithm

    NASA Astrophysics Data System (ADS)

    Hewson, W.; Barkley, M. P.; Gonzalez Abad, G.; Bösch, H.; Kurosu, T.; Spurr, R.; Tilstra, L. G.

    2015-10-01

    Space-borne observations of formaldehyde (HCHO) are frequently used to derive surface emissions of isoprene, an important biogenic volatile organic compound. The conversion of retrieved HCHO slant column concentrations from satellite line-of-sight measurements to vertical columns is determined through application of an air mass factor (AMF), accounting for instrument viewing geometry, radiative transfer, and vertical profile of the absorber in the atmosphere. This step in the trace gas retrieval is subject to large errors. This work presents the AMF algorithm in use at the University of Leicester (UoL), which introduces scene-specific variables into a per-observation full radiative transfer AMF calculation, including increasing spatial resolution of key environmental parameter databases, input variable area weighting, instrument-specific scattering weight calculation, and inclusion of an ozone vertical profile climatology. Application of these updates to HCHO slant columns from the GOME-2 instrument is shown to typically adjust the AMF by ±20 %, compared to a reference algorithm without these advanced parameterisations. On average the GOME-2 AMFs increase by 4 %, with over 70 % of locations having an AMF of 0-20 % larger than originally, largely resulting from the use of the latest GOME-2 reflectance product. Furthermore, the new UoL algorithm also incorporates a full radiative transfer error calculation for each scene to help characterise AMF uncertainties. Global median AMF errors are typically 50-60 %, and are driven by uncertainties in the HCHO profile shape and its vertical distribution relative to clouds and aerosols. If uncertainty on the a priori HCHO profile is relatively small (< 10 %) then the median AMF total error decreases to about 30-40 %.

  1. Air Mass Factor Formulation for Spectroscopic Measurements from Satellites: Application to Formaldehyde Retrievals from the Global Ozone Monitoring Experiment

    NASA Technical Reports Server (NTRS)

    Palmer, Paul I.; Jacob, Daniel J.; Chance, Kelly; Martin, Randall V.; Spurr, Robert J. D.; Kurosu, Thomas P.; Bey, Isabelle; Yantosca, Robert; Fiore, Arlene; Li, Qinbin

    2004-01-01

    We present a new formulation for the air mass factor (AMF) to convert slant column measurements of optically thin atmospheric species from space into total vertical columns. Because of atmospheric scattering, the AMF depends on the vertical distribution of the species. We formulate the AMF as the integral of the relative vertical distribution (shape factor) of the species over the depth of the atmosphere, weighted by altitude-dependent coefficients (scattering weights) computed independently from a radiative transfer model. The scattering weights are readily tabulated, and one can then obtain the AMF for any observation scene by using shape factors from a three dimensional (3-D) atmospheric chemistry model for the period of observation. This approach subsequently allows objective evaluation of the 3-D model with the observed vertical columns, since the shape factor and the vertical column in the model represent two independent pieces of information. We demonstrate the AMF method by using slant column measurements of formaldehyde at 346 nm from the Global Ozone Monitoring Experiment satellite instrument over North America during July 1996. Shape factors are cumputed with the Global Earth Observing System CHEMistry (GEOS-CHEM) global 3-D model and are checked for consistency with the few available aircraft measurements. Scattering weights increase by an order of magnitude from the surface to the upper troposphere. The AMFs are typically 20-40% less over continents than over the oceans and are approximately half the values calculated in the absence of scattering. Model-induced errors in the AMF are estimated to be approximately 10%. The GEOS-CHEM model captures 50% and 60% of the variances in the observed slant and vertical columns, respectively. Comparison of the simulated and observed vertical columns allows assessment of model bias.

  2. An Active Flow Circulation Controlled Flap Concept for General Aviation Aircraft Applications

    NASA Technical Reports Server (NTRS)

    Jones, Gregory S.; Viken, Sally A.; Washburn, Anthony E.; Jenkins, Luther N.; Cagle, C. Mark

    2002-01-01

    A recent focus on revolutionary aerodynamic concepts has highlighted the technology needs of general aviation and personal aircraft. New and stringent restrictions on these types of aircraft have placed high demands on aerodynamic performance, noise, and environmental issues. Improved high lift performance of these aircraft can lead to slower takeoff and landing speeds that can be related to reduced noise and crash survivability issues. Circulation Control technologies have been around for 65 years, yet have been avoided due to trade offs of mass flow, pitching moment, perceived noise etc. The need to improve the circulation control technology for general aviation and personal air-vehicle applications is the focus of this paper. This report will describe the development of a 2-D General Aviation Circulation Control (GACC) wing concept that utilizes a pulsed pneumatic flap.

  3. Measurement and analysis of aerosol and black carbon in the southwestern United States and Panama and their dependence on air mass origin

    NASA Astrophysics Data System (ADS)

    Junker, C.; Sheahan, J. N.; Jennings, S. G.; O'Brien, P.; Hinds, B. D.; Martinez-Twary, E.; Hansen, A. D. A.; White, C.; Garvey, D. M.; Pinnick, R. G.

    2004-07-01

    Total aerosol mass loading, aerosol absorption, and black carbon (BC) content were determined from aerosol collected on 598 quartz fiber filters at a remote, semiarid site near Orogrande, New Mexico from December 1989 to October 1995. Aerosol mass was determined by weighing filters before and after exposure, and aerosol absorption was determined by measuring the visible light transmitted through loaded filter samples and converting these measurements to aerosol absorption. BC content was determined by measuring visible light transmitted through filter samples before and after firing and converting the absorption to BC mass, assuming a BC absorption cross section of 19 m2/g in the fiber filter medium. Two analyses were then performed on each of the logged variables: an autoregressive integrating moving average (ARIMA) analysis and a decomposition analysis using an autoregressive model to accommodate first-order autocorrelation. The two analyses reveal that BC mass has no statistically significant seasonal dependence at the 5% level of significance but only random fluctuations varying around an average annual value that has a long-term decreasing trend (from 0.16 to 0.11 μg/m3 during 1990-1995). Aerosol absorption, which is dominated by BC, also displays random fluctuations about an average value, and decreases from 1.9 Mm-1 to 1.3 Mm-1 during the same period. Unlike BC, aerosol mass at the Orogrande site displays distinctly different character. The analyses reveal a pronounced seasonal dependence, but no long-term trend for aerosol mass. The seasonal indices resulting from the autoregression analysis have a minimum in January (-0.78) and maximum in June (+0.58). The geometric mean value over the 1990-1995 period for aerosol mass is 16.0 μg/m3. Since BC aerosol at the Orogrande site is a product of long-range atmospheric transport, a back trajectory analysis of air masses was conducted. Back trajectory analyses indicate that air masses traversing high population

  4. Mobile selected ion flow tube mass spectrometry (SIFT-MS) devices and their use for pollution exposure monitoring in breath and ambient air-pilot study.

    PubMed

    Storer, Malina; Salmond, Jennifer; Dirks, Kim N; Kingham, Simon; Epton, Michael

    2014-09-01

    Studies of health effects of air pollution exposure are limited by inability to accurately determine dose and exposure of air pollution in field trials. We explored the feasibility of using a mobile selected ion flow tube mass spectrometry (SIFT-MS) device, housed in a van, to determine ambient air and breath levels of benzene, xylene and toluene following exercise in areas of high motor vehicle traffic. The breath toluene, xylene and benzene concentration of healthy subjects were measured before and after exercising close to a busy road. The concentration of the volatile organic compounds (VOCs), in ambient air were also analysed in real time. Exercise close to traffic pollution is associated with a two-fold increase in breath VOCs (benzene, xylene and toluene) with levels returning to baseline within 20 min. This effect is not seen when exercising away from traffic pollution sources. Situating the testing device 50 m from the road reduced any confounding due to VOCs in the inspired air prior to the breath testing manoeuvre itself. Real-time field testing for air pollution exposure is possible using a mobile SIFT-MS device. This device is suitable for exploring exposure and dose relationships in a number of large scale field test scenarios.

  5. Characteristics of particle number and mass emissions during heavy-duty diesel truck parked active DPF regeneration in an ambient air dilution tunnel

    NASA Astrophysics Data System (ADS)

    Yoon, Seungju; Quiros, David C.; Dwyer, Harry A.; Collins, John F.; Burnitzki, Mark; Chernich, Donald; Herner, Jorn D.

    2015-12-01

    Diesel particle number and mass emissions were measured during parked active regeneration of diesel particulate filters (DPF) in two heavy-duty diesel trucks: one equipped with a DPF and one equipped with a DPF + SCR (selective catalytic reduction), and compliant with the 2007 and 2010 emission standards, respectively. The emission measurements were conducted using an ambient air dilution tunnel. During parked active regeneration, particulate matter (PM) mass emissions measured from a 2007 technology truck were significantly higher than the emissions from a 2010 technology truck. Particle number emissions from both trucks were dominated by nucleation mode particles having a diameter less than 50 nm; nucleation mode particles were orders of magnitude higher than accumulation mode particles having a diameter greater than 50 nm. Accumulation mode particles contributed 77.8 %-95.8 % of the 2007 truck PM mass, but only 7.3 %-28.2 % of the 2010 truck PM mass.

  6. Control of a Circulating Fluidized Bed

    SciTech Connect

    Shim, Hoowang; Rickards, Gretchen; Famouri, Parviz; Turton, Richard; Sams, W. Neal; Koduro, Praveen; Patankar, Amol; Davari, Assad; Lawson, Larry; Boyle, Edward J.

    2001-11-06

    Two methods for optimally controlling the operation of a circulating fluidized bed are being investigated, neural network control and Kalman filter control. The neural network controls the solids circulation rate by adjusting the flow of move air in the non-mechanical valve. Presented is the method of training the neural network from data generated by the circulating fluidized bed (CFB), the results of a sensitivity study indicating that adjusting the move air can control solids flow, and the results of controlling solids circulation rate. The Kalman filter approach uses a dynamic model and a measurement model of the standpipe section of the CFB. Presented are results showing that a Kalman filter can successfully find the standpipe bed height.

  7. Easy dual-mode ambient mass spectrometry with Venturi self-pumping, canned air, disposable parts and voltage-free sonic-spray ionization.

    PubMed

    Schwab, Nicolas V; Porcari, Andreia M; Coelho, Mirela B; Schmidt, Eduardo M; Jara, Jose L; Visentainer, Jesui V; Eberlin, Marcos N

    2012-06-01

    An exceptionally easy to assemble source for ambient mass spectrometry is described. Based on Venturi easy ambient sonic-spray ionization (V-EASI), the source was further simplified by the use of a can of compressed air which simultaneously provides solution or solvent Venturi self-pumping and continuous, stable and abundant low-noise ion signal via voltage-free sonic-spraying. Further simplification was also attained by the use of inexpensive and readily commercially available parts: a surgical 2-way catheter, an aerosol can of compressed air, a 30 cm long fused-silica capillary and a hypodermic needle. This "Spartan" V-EASI source seems to offer one of the easiest and cheapest ways to make ions for ambient desorption/ionization mass spectrometry analysis of both liquid and solid samples. PMID:22349120

  8. Long-term measurements of particle number size distributions and the relationships with air mass history and source apportionment in the summer of Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Hu, M.; Wu, Z. J.; Yue, D. L.; He, L. Y.; Huang, X. F.; Liu, X. G.; Wiedensohler, A.

    2013-10-01

    A series of long-term and temporary measurements were conducted to study the improvement of air quality in Beijing during the Olympic Games period (8-24 August 2008). To evaluate actions taken to improve the air quality, comparisons of particle number and volume size distributions of August 2008 and 2004-2007 were performed. The total particle number and volume concentrations were 14 000 cm-3 and 37 μm-3 cm-3 in August of 2008, respectively. These were reductions of 41% and 35% compared with mean values of August 2004-2007. A cluster analysis on air mass history and source apportionment were performed, exploring reasons for the reduction of particle concentrations. Back trajectories were classified into five major clusters. Air masses from the south direction are always associated with pollution events during the summertime in Beijing. In August 2008, the frequency of air mass arriving from the south was 1.3 times higher compared to the average of the previous years, which however did not result in elevated particle volume concentrations in Beijing. Therefore, the reduced particle number and volume concentrations during the 2008 Beijing Olympic Games cannot be only explained by meteorological conditions. Four factors were found influencing particle concentrations using a positive matrix factorization (PMF) model. They were identified as local and remote traffic emissions, combustion sources as well as secondary transformation. The reductions of the four sources were calculated to 47%, 44%, 43% and 30%, respectively. The significant reductions of particle number and volume concentrations may attribute to actions taken, focusing on primary emissions, especially related to the traffic and combustion sources.

  9. Quantification of Intact and Truncated Stromal Cell-Derived Factor-1α in Circulation by Immunoaffinity Enrichment and Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Weixun; Choi, Bernard K.; Li, Wenyu; Lao, Zhege; Lee, Anita Y. H.; Souza, Sandra C.; Yates, Nathan A.; Kowalski, Timothy; Pocai, Alessandro; Cohen, Lucinda H.

    2014-04-01

    Stromal cell-derived factor 1α (SDF-1α) or CXCL12 is a small pro-inflammatory chemoattractant cytokine and a substrate of dipeptidyl peptidase IV (DPP-IV). Proteolytic cleavage by DPP-IV inactivates SDF-1α and attenuates its interaction with CXCR4, its cell surface receptor. To enable investigation of suppression of such inactivation with pharmacologic inhibition of DPP-IV, we developed quantitative mass spectrometric methods that differentiate intact SDF-1α from its inactive form. Using top-down strategy in quantification, we demonstrated the unique advantage of keeping SDF-1α's two disulfide bridges intact in the analysis. To achieve the optimal sensitivity required for quantification of intact and truncated SDF-1α at endogenous levels in blood, we coupled nano-flow tandem mass spectrometry with antibody-based affinity enrichment. The assay has a quantitative range of 20 pmol/L to 20 nmol/L in human plasma as well as in rhesus monkey plasma. With only slight modification, the same assay can be used to quantify SDF-1α in mice. Using two in vivo animal studies as examples, we demonstrated that it was critical to differentiate intact SDF-1α from its truncated form in the analysis of biomarkers for pharmacologic inhibition of DPP-IV activity. These novel methods enable translational research on suppression of SDF-1 inactivation with DPP-IV inhibition and can be applied to relevant clinical samples in the future to yield new insights on change of SDF-1α levels in disease settings and in response to therapeutic interventions.

  10. Modelled Circulation In Storfjorden

    NASA Astrophysics Data System (ADS)

    Skogseth, R.; Asplin, L.

    tidal modeling in the Barents Sea including Storfjorden with Heleysundet and Freemansundet closed gave a half-phase shift between tides in inner Storfjorden and northern Barents Sea that induced large difference in water level. The present tidal model simulations of Storfjorden with Freemansundet opened also showed a phase shift between tides in inner Storfjorden and northern Barents Sea indicating that the phase shift does ex- ist independent of the sounds and that the strong tidal currents are due to the phase shift. The residual current from the model simulation probably shows a pronounced cyclonic coastal circulation in Storfjorden. Artificial tracers are used in the simula- tions to depict the residual current. The role of surface buoyancy flux north of the sill for enhancement of the cyclonical circulation due to a larger horizontal density gra- 1 dient will be discussed. Other possible mechanisms forcing the cyclonic circulation, which will be studied and discussed, are fresh water input from rivers, glaciers and melted sea ice, and the initial hydrographic fields in the model. Alternatively, initial fields based on extensive hydrographical surveys (Skogseth, Haugan &Nøst: Water mass transformations in Storfjorden, submitted EGS 2002) can be used in the model providing better resolution and representation of the present fresh water. 2

  11. Who should take responsibility for decisions on internationally recommended datasets? The case of the mass concentration of mercury in air at saturation

    NASA Astrophysics Data System (ADS)

    Brown, Richard J. C.; Brewer, Paul J.; Ent, Hugo; Fisicaro, Paola; Horvat, Milena; Kim, Ki-Hyun; Quétel, Christophe R.

    2015-10-01

    This paper considers how decisions on internationally recommended datasets are made and implemented and, further, how the ownership of these decisions comes about. Examples are given of conventionally agreed data and values where the responsibility is clear and comes about through official designation or by common usage and practice over long time periods. The example of the dataset describing the mass concentration of mercury in air at saturation is discussed in detail. This is a case where there are now several competing datasets that are in disagreement with each other, some with historical authority and some more recent but, arguably, with more robust metrological traceability to the SI. Further, it is elaborated that there is no body charged with the responsibility to make a decision on an international recommendation for such a dataset. This has led to the situation where several competing datasets are in use simultaneously. Close parallels are drawn with the current debate over changes to the ozone absorption cross section, which has equal importance to the measurement of ozone amount fraction in air and to subsequent compliance with air quality legislation. It is noted that in the case of the ozone cross section there is already a committee appointed to deliberate over any change. We make the proposal that a similar committee, under the auspices of IUPAC or the CIPM’s CCQM (if it adopted a reference data function) could be formed to perform a similar role for the mass concentration of mercury in air at saturation.

  12. Characterization of volatile organic compounds (VOCs) in Asian and North American pollution plumes during INTEX-B: identification of specific Chinese air mass tracers

    NASA Astrophysics Data System (ADS)

    Barletta, B.; Meinardi, S.; Simpson, I. J.; Atlas, E. L.; Beyersdorf, A. J.; Baker, A. K.; Blake, N. J.; Yang, M.; Midyett, J. R.; Novak, B. J.; McKeachie, R. J.; Fuelberg, H. E.; Sachse, G. W.; Avery, M. A.; Campos, T.; Weinheimer, A. J.; Sherwood Rowland, F.; Blake, D. R.

    2009-03-01

    We present results from the Intercontinental Chemical Transport Experiment - Phase B (INTEX-B) aircraft mission conducted in spring 2006. By analyzing the mixing ratios of volatile organic compounds (VOCs) measured during the second part of the field campaign, together with kinematic back trajectories, we were able to identify five plumes originating from China, four plumes from other Asian regions, and three plumes from the United States. To identify specific tracers for the different air masses, we focused on characterizing the VOC composition of these different pollution plumes. The Chinese and other Asian air masses were significantly enhanced in carbonyl sulfide (OCS) and methyl chloride (CH3Cl), while all CFC replacement compounds were elevated in US plumes, particularly HCFC-134a. Although elevated mixing ratios of Halon-1211 were measured in some of the Chinese plumes, several measurements at background levels were also observed. After analyzing the VOC distribution in the Chinese pollution plumes and the correlations among selected compounds, we suggest the use of a suite of species, rather than the use of a single gas, to be used as specific tracers of Chinese air masses (namely OCS, CH3Cl, 1,2-dichloroethane, and Halon-1211). In an era of constantly changing halocarbon usage patterns, this suite of gases best reflects new emission characteristics from China.

  13. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  14. PM2.5 chemical composition at a rural background site in Central Europe, including correlation and air mass back trajectory analysis

    NASA Astrophysics Data System (ADS)

    Schwarz, Jaroslav; Cusack, Michael; Karban, Jindřich; Chalupníčková, Eva; Havránek, Vladimír; Smolík, Jiří; Ždímal, Vladimír

    2016-07-01

    of fresh, local aerosol and aged, long-range transport aerosol. The influences of different air masses were also investigated. The lowest concentrations of PM2.5 were recorded under the influence of marine air masses from the NW, which were also marked by increased concentrations of marine aerosol. In contrast, the highest concentrations of PM2.5 and most major chemical components were measured during periods when continental easterly air masses were dominant.

  15. Retrieval of Vertical Columns of Sulfur Dioxide From SCIAMACHY and OMI: Air Mass Factor Algorithm Development and Validation

    NASA Astrophysics Data System (ADS)

    Lee, C.; Martin, R. V.; Donkelaar, A. V.; O'Byrne, G.; Krotkov, N.; Richter, A.; Huey, G.; Holloway, J. S.

    2009-05-01

    Sulfur dioxide (SO2) is released into the atmosphere as a result of both anthropogenic activities and natural phenomena. SO2 oxidizes rapidly in the atmosphere, leading to aerosol formation and acid deposition. Outstanding questions exist about SO2 emissions and its atmospheric chemistry. Global mapping of atmospheric SO2 concentrations can provide critical information on its emissions and transport and generally improve scientific understanding of its atmospheric chemistry. Here, we present an improved retrieval of sulfur dioxide (SO2) vertical columns from satellite instruments (SCIAMACHY and OMI) that measure solar backscattered UV radiance. Particular attention is devoted to development of a local air mass factor (AMF) algorithm to convert slant columns to vertical columns. For each SCIAMACHY and OMI observation, we calculate an AMF from the relative vertical SO2 distribution (shape factor) determined locally with a 3-D global model of atmospheric chemistry (GEOS-Chem), weighted by altitude-dependent scattering weights computed with a radiative transfer model (LIDORT). Seasonal mean instrument sensitivity to SO2 (AMF) is generally twice as high over ocean than land. Mineral dust can reduce seasonal mean instrument sensitivity by 50%. Mean relative vertical profiles of SO2 simulated with GEOS-Chem and used in the AMF calculation are highly consistent with airborne in situ measurements (INTEX-A and INTEX-B); differences would affect the retrieved SO2 columns by 10%. The retrieved vertical columns are validated (r = 0.9) with coincident airborne in-situ measurements (INTEX-A, INTEX-B, and a campaign over East China). A global uniform AMF would reduce the correlation with aircraft measurements by 0.1 - 0.2. The overall error assessment leads to 45 - 80% errors for yearly averages over the polluted regions. Seasonal mean SO2 columns retrieved from SCIAMACHY and OMI for 2006 are significantly spatially correlated with those from GEOS-Chem, in particular over the

  16. Intercomparison of OMI NO2 and HCHO air mass factor calculations: recommendations and best practices for retrievals

    NASA Astrophysics Data System (ADS)

    Lorente Delgado, Alba; Klaas Boersma, Folkert; Hilboll, Andreas; Richter, Andreas; Yu, Huan; van Roozendael, Michel; Dörner, Steffen; Wagner, Thomas; Barkley, Michael; Lamsal, Lok; Lin, Jintai; Liu, Mengyao

    2016-04-01

    We present a detailed comparison of the air mass factor (AMF) calculation process used by various research groups for OMI satellite retrievals of NO2 and HCHO. Although satellite retrievals have strongly improved over the last decades, there is still a need to better understand and reduce the uncertainties associated with every retrieval step of satellite data products, such as the AMF calculation. Here we compare and evaluate the different approaches used to calculate AMFs by several scientific groups (KNMI (WUR), IASB-BIRA, IUP-UNI. BREMEN, MPI-C, NASA GSFC, LEICESTER UNI. and PEKING UNI.). Each group calculated altitude dependent (box-) AMFs and clear sky and total tropospheric AMFs for several OMI orbits. First, European groups computed AMFs for one OMI orbit using common settings for the choice of surface albedo data, terrain height, cloud treatment and a priori vertical profile. Second, every group computed AMFs for two complete days in different seasons using preferred settings for the ancillary data and cloud treatment as a part of a Round Robin exercise. Box-AMFs comparison showed good consistency and underlined the importance of a correct treatment of the physical processes affecting the effective light path and the vertical discretization of the atmosphere. Using common settings, tropospheric NO2 AMFs in polluted pixels on average agreed within 4.7% whereas in remote pixels agreed within 3.5%. Using preferred settings relative differences between AMFs increase up to 15-30%. This increase is traced back to the different choices and assumptions made throughout the AMF calculation, which affect the final AMF values and thus the uncertainty in the AMF calculation. Differences between state of the art cloud treatment approaches highlight the importance of an accurate cloud correction: total and clear sky AMFs in polluted conditions differ by up to 40% depending on the retrieval scenario. Based on the comparison results, specific recommendations on best

  17. Release of PCDD/PCDF to air and land during open burning of sugarcane and forest litter over soil fortified with mass labelled PCDD/PCDF

    NASA Astrophysics Data System (ADS)

    Black, Robert R.; (Mick) Meyer, Carl P.; Yates, Alan; Van Zwieten, Lukas; Chittim, Brock G.; Mueller, Jochen F.

    2012-11-01

    The contribution of PCDD/PCDF emissions from soil during open burning of biomass was examined. Mass labelled PCDD/PCDF was added to soil containing native PCDD/PCDF and biomass was laid out on this soil and burnt, simulating sugarcane trash and forest fires. Smoke samples were collected using a high volume portable field sampler. After each fire the concentration of all mass labelled PCDD/PCDF congeners in the surface soil decreased, however, the concentration of some native 2,3,7,8 substituted congeners increased, indicating that formation was occurring. Mass labelled PCDD/PCDF congeners were detected in all ash samples, mean 2.8 pg g-1 (range 0.5-8 pg g-1), demonstrating release from the soil. Additionally, mass labelled PCDD/PCDF congeners were detected in all air samples mean 1.2 μg (t fuel)-1 (range 0.2-2.0 μg (t fuel)-1), again demonstrating release from the soil. Native 2,3,7,8 substituted congeners detected in the air samples were dominated (in terms of contribution to total congener mass) by Cl8DD (90% for forest litter and 77% for sugarcane). The major contributor to TEQ of emissions from both forest litter and sugarcane was 1, 2, 3, 7, 8-Cl5DD (40-64% and 57-75%, respectively). These results demonstrate that release of PCDD/PCDF from soil to air and land occurs during open burning of biomass when soil temperatures are sufficiently elevated.

  18. Erosional and depositional contourite features at the transition between the western Scotia Sea and southern South Atlantic Ocean: links with regional water-mass circulation since the Middle Miocene

    NASA Astrophysics Data System (ADS)

    Pérez, Lara F.; Hernández-Molina, F. Javier; Esteban, Federico D.; Tassone, Alejandro; Piola, Alberto R.; Maldonado, Andrés; Preu, Benedict; Violante, Roberto A.; Lodolo, Emanuele

    2015-08-01

    The aim of the present study was to characterise the morpho-sedimentary features and main stratigraphic stacking pattern off the Tierra del Fuego continental margin, the north-western sector of the Scotia Sea abyssal plain (Yaghan Basin) and the Malvinas/Falkland depression, based on single- and multi-channel seismic profiles. Distinct contourite features were identified within the sedimentary record from the Middle Miocene onwards. Each major drift developed in a water depth range coincident with a particular water mass, contourite terraces on top of some of these drifts being associated with interfaces between water masses. Two major palaeoceanographic changes were identified. One took place in the Middle Miocene with the onset of Antarctic Intermediate Water flow and the enhancement of Circumpolar Deep Water (CDW) flow, coevally with the onset of Weddell Sea Deep Water flow in the Scotia Sea. Another palaeoceanographic change occurred on the abyssal plain of the Yaghan Basin in the Late Miocene as a consequence of the onset of Southeast Pacific Deep Water flow and its complex interaction with the lower branch of the CDW. Interestingly, these two periods of change in bottom currents are coincident with regional tectonic episodes, as well as climate and Antarctic ice sheet oscillations. The results convincingly demonstrate that the identification of contourite features on the present-day seafloor and within the sedimentary record is the key for decoding the circulation of water masses in the past. Nevertheless, further detailed studies, especially the recovery of drill cores, are necessary to establish a more robust chronology of the evolutionary stages at the transition between the western Scotia Sea and the southern South Atlantic Ocean.

  19. Air circulation under reduced atmospheric pressures

    NASA Astrophysics Data System (ADS)

    Hillhouse, Lendell E.

    The control of heat exchange is vital for plant life in off-world, low pressure, greenhouses. The ability to control this process was limited by methodology and technology. Mathematical models, based on classical mechanics are created to enhance our control capabilities. Data is collected using various sensors placed inside the Low Pressure Test Bed (LPTB) Chamber at Kennedy Space Center. Data from those sensors became non-linear at various pressures below 25 kPa. We introduced mathematical calibration corrections and found that sensor data linearity could be extended to a greater range of pressures. These calibration corrections allow for sensor calibration corrections in operational environments that differ from the environment of calibration (normal Earth atmospheric pressure).

  20. Operational Use of the AIRS Total Column Ozone Retrievals Along with the RGB Air Mass Product as Part of the GOES-R Proving Ground

    NASA Technical Reports Server (NTRS)

    Folmer, Michael; Zavodsky, Bradley; Molthan, Andrew

    2012-01-01

    The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Hydrometeorological Prediction Center (HPC) and Ocean Prediction Center (OPC) provide short-term and medium-range forecast guidance of heavy precipitation, strong winds, and other features often associated with mid-latitude cyclones over both land and ocean. As a result, detection of factors that lead to rapid cyclogenesis and high wind events is key to improving forecast skill. One phenomenon that has been identified with these events is the stratospheric intrusion that occurs near tropopause folds. This allows for deep mixing near the top of the atmosphere where dry air high in ozone concentrations and potential vorticity descends (sometimes rapidly) deep into the mid-troposphere. Observations from satellites can aid in detection of these stratospheric air intrusions (SAI) regions. Specifically, multispectral composite imagery assign a variety of satellite spectral bands to the red, green, and blue (RGB) color components of imagery pixels and result in color combinations that can assist in the detection of dry stratospheric air associated with PV advection, which in turn may alert forecasters to the possibility of a rapidly strengthening storm system. Single channel or RGB satellite imagery lacks quantitative information about atmospheric moisture unless the sampled brightness temperatures or other data are converted to estimates of moisture via a retrieval process. Thus, complementary satellite observations are needed to capture a complete picture of a developing storm system. Here, total column ozone retrievals derived from a hyperspectral sounder are used to confirm the extent and magnitude of SAIs. Total ozone is a good proxy for defining locations and intensity of SAIs and has been used in studies evaluating that phenomenon (e.g. Tian et al. 2007, Knox and Schmidt 2005). Steep gradients in values of total ozone seen by satellites have been linked

  1. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-04-01

    The early twentieth century Arctic warming (ETCAW) between 1920-1940 is an exceptional feature of climate dynamics in the last century and its warming rate was only recently matched by anthropogenic global warming amplification in the Arctic region. However, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We use these gridded datasets to investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analysing heat flux components and regional differences, it was found that climate models are not able to reproduce the heat flux evolution shown by reanalysis and reconstruction datasets. These datasets compute an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis revealed the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it could be shown that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  2. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-06-01

    The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  3. Isentropic analysis of the Indian Summer Monsoon circulation and its implications for the active and break periods

    NASA Astrophysics Data System (ADS)

    Pauluis, O. M.; Sandeep, S.; Ravindran, A. M.

    2014-12-01

    The atmospheric flow during the Indian Summer Monsoon here is analyzed in isentropic coordinates in two different ways. First, the lateral mass transport fo air is separated in terms of both the potential temperature and equivalent potential temperature. This approach, originally developed to analyze the global meridional circulation, makes it possible to identify the thermodynamic properties of the inflow and outflow. It is shown here how the properties of various air masses, such as the inflow of warm moist air in the boundary layer, upper tropospheric outflow, and midlatitudes dry air intrusion, can be systematically identified. Second, we analyze the vertical overturning in terms of terms of the equivalent potential temperature of the ascending and subsiding air parcels over the indian subcontinent, which allows us to further infer the thermodynamic transformation occurring during the monsoon. This technique is first used to look at the evolution of the flow through the seasonal cycle. We then further analyze the circulation patterns associated with monsoon breaks and active periods. In doing so, we identify midtropospheric in usions of dry air from the midlatitudes as a key precursor of monsoon breaks. The meteorological conditions associated for such intrusion to reach the subcontinent are then discussed.

  4. Highly sensitive determination of polycyclic aromatic hydrocarbons in ambient air dust by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction.

    PubMed

    Krupadam, Reddithota J; Bhagat, Bhagyashree; Khan, Muntazir S

    2010-08-01

    A method based on solid--phase extraction with a molecularly imprinted polymer (MIP) has been developed to determine five probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry (GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phase extraction (SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L(-1) (r = 0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials--powdered activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD)--and it was shown that the extraction capacity of the MIP was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L(-1) for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic PAHs in air dust of industrial zones and satisfactory results were obtained.

  5. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.; Molthan, A. L.

    2013-01-01

    Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

  6. Circulating glioma biomarkers

    PubMed Central

    Kros, Johan M.; Mustafa, Dana M.; Dekker, Lennard J.M.; Sillevis Smitt, Peter A.E.; Luider, Theo M.; Zheng, Ping-Pin

    2015-01-01

    Validated biomarkers for patients suffering from gliomas are urgently needed for standardizing measurements of the effects of treatment in daily clinical practice and trials. Circulating body fluids offer easily accessible sources for such markers. This review highlights various categories of tumor-associated circulating biomarkers identified in blood and cerebrospinal fluid of glioma patients, including circulating tumor cells, exosomes, nucleic acids, proteins, and oncometabolites. The validation and potential clinical utility of these biomarkers is briefly discussed. Although many candidate circulating protein biomarkers were reported, none of these have reached the required validation to be introduced for clinical practice. Recent developments in tracing circulating tumor cells and their derivatives as exosomes and circulating nuclear acids may become more successful in providing useful biomarkers. It is to be expected that current technical developments will contribute to the finding and validation of circulating biomarkers. PMID:25253418

  7. High-precision measurements of mercury vapor in air: Design of a six-port-manifold mass flow controller system and evaluation of mass flow errors at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Hyun; Lindberg, Steven E.

    1994-03-01

    We constructed an atmospheric sampling system for Hg vapor that utilizes a single vacuum pump connected via a manifold to six separate mass flow controllers (MFC). The manifold system reduces the size and power requirements for collection of replicate samples, is ideally suited for use on meteorological towers, and achieves the precise control of air-sampling volumes required for computing air/surface exchange rates from concentration gradients of Hg vapor. In testing our air sampling systems, we found consistent calibration errors between the manufacturer's calibrations and a standard bubble flow meter. Errors as high as 30% decreased systematically with increasing flow rate to values of 3-5% at near-maximum flow. The relative error patterns established between adjacent MFC units in each system were found to be relatively stable over time. Using gold-coated sand amalgamation traps for Hg vapor and the flow correction factors computed from our calibrations, we routinely achieve precision for replicate measurements of Hg vapor in background air of 0.5-2% (expressed as relative standard errors of mean concentrations of 1.5-3.5 ng/m3). Application of the flow correction factors measurably decreases the level of bias between mean concentrations of Hg vapor measured with adjacent sampling systems and is necessary to reduce uncertainty associated with quantifying gradients in atmospheric concentrations.

  8. Numerical investigation of interfacial mass transport resistance and two-phase flow in PEM fuel cell air channels

    NASA Astrophysics Data System (ADS)

    Koz, Mustafa

    Proton exchange membrane fuel cells (PEMFCs) are efficient and environmentally friendly electrochemical engines. The performance of a PEMFC is adversely affected by oxygen (O2) concentration loss from the air flow channel to the cathode catalyst layer (CL). Oxygen transport resistance at the gas diffusion layer (GDL) and air channel interface is a non-negligible component of the O2 concentration loss. Simplified PEMFC performance models in the available literature incorporate the O2 resistance at the GDL-channel interface as an input parameter. However, this parameter has been taken as a constant so far in the available literature and does not reflect variable PEMFC operating conditions and the effect of two-phase flow in the channels. This study numerically calculates the O2 transport resistance at the GDL-air channel interface and expresses this resistance through the non-dimensional Sherwood number (Sh). Local Sh is investigated in an air channel with multiple droplets and films inside. These water features are represented as solid obstructions and only air flow is simulated. Local variations of Sh in the flow direction are obtained as a function of superficial air velocity, water feature size, and uniform spacing between water features. These variations are expressed with mathematical expressions for the PEMFC performance models to utilize and save computational resources. The resulting mathematical correlations for Sh can be utilized in PEMFC performance models. These models can predict cell performance more accurately with the help of the results of this work. Moreover, PEMFC performance models do not need to use a look-up table since the results were expressed through correlations. Performance models can be kept simplified although their predictions will become more realistic. Since two-phase flow in channels is experienced mostly at lower temperatures, performance optimization at low temperatures can be done easier.

  9. An online educational atmospheric global circulation model

    NASA Astrophysics Data System (ADS)

    Navarro, T.; Schott, C.; Forget, F.

    2015-10-01

    As part of online courses on exoplanets of Observatoire de Paris, an online tool designed to vizualise outputs of the Laboratoire de Métérologie Dynamique (LMD) Global Circulation Model (GCM) for various atmospheric circulation regimes has been developed. It includes the possibility for students to visualize 1D and 2D plots along with animations of atmospheric quantities such as temperature, winds, surface pressure, mass flux, etc... from a state-of-the-art model.

  10. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    PubMed

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-01

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs.

  11. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    PubMed

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-01

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs. PMID:24678766

  12. Seasonal, anthropogenic, air mass, and meteorological influences on the atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs): Evidence for the importance of diffuse combustion sources

    SciTech Connect

    Lee, R.G.M.; Green, N.J.L.; Lohmann, R.; Jones, K.C.

    1999-09-01

    Sampling programs were undertaken to establish air polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations at a semirural site on the northwest coast of England in autumn and summer and to investigate factors causing their variability. Changing source inputs, meteorological parameters, air masses, and the impact of a festival when it is customary to light fireworks and bonfires were investigated. Various lines of evidence from the study point to diffuse, combustion-related sources being a major influence on ambient air concentrations. Higher PCDD/F concentrations were generally associated with air masses that had originated and moved over land, particularly during periods of low ambient temperature. Low concentrations were associated with air masses that had arrived from the Atlantic Ocean/Irish Sea to the west of the sampling site and had little or no contact with urban/industrialized areas. Concentrations in the autumn months were 2 to 10 times higher than those found in the summer.

  13. The effects of air mass transport, seasonality, and meteorology on pollutant levels at the Iskrba regional background station (1996-2014)

    NASA Astrophysics Data System (ADS)

    Poberžnik, Matevž; Štrumbelj, Erik

    2016-06-01

    Our main goal was to estimate the effects of long-range air transport on pollutant concentrations measured at the Iskrba regional background station (Slovenia). We cluster back-trajectories into categories and simultaneously model the effects of meteorology, seasonality, trends, and air mass trajectory clusters using a Bayesian statistical approach. This simplifies the interpretation of results and allows us to better identify the effects of individual variables, which is important, because pollutant concentrations, meteorology, and trajectories are seasonal and correlated. Similar to related work from other European sites, we find that slow and faster moving trajectories from eastern Europe and the northern part of the Balkan peninsula are associated with higher pollutant levels, while fast-moving trajectories from the Atlantic are associated with lower pollutant concentration. Overall, pollutant concentrations have decreased in the studied period.

  14. Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

    NASA Astrophysics Data System (ADS)

    Mohammad, Abdulrahman Th.; Mat, Sohif Bin; Sulaiman, M. Y.; Sopian, K.; Al-abidi, Abduljalil A.

    2013-11-01

    A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.

  15. Combustion of a Methane-Air Mixture in a Slot Burner with an Inert Insert in Mass Transfer to the Environment

    NASA Astrophysics Data System (ADS)

    Krainov, A. Yu.; Moiseeva, K. M.

    2016-03-01

    A problem on combustion of a methane-air mixture in a slot burner with an internal insert in mass transfer from the burner's exterior wall to the environment has been solved. A mathematical formulation of the problem takes account of the dependence of the diffusion, thermal-conductivity, and heat-transfer coefficients on temperature, and also of the heat removal from the gas to the environment by convective and radiant heat transfer. A numerical investigation has been carried out in a one-dimensional mathematical formulation of the problem in dimensional variables. The boundary of existence of a stable high-temperature regime of combustion of the methane-air mixture has been determined as a function of the rate of feed of the gas, the environmental temperature, and the width of the flow area of the burner.

  16. Determination of seven pyrethroids biocides and their synergist in indoor air by thermal-desorption gas chromatography/mass spectrometry after sampling on Tenax TA ® passive tubes.

    PubMed

    Raeppel, Caroline; Appenzeller, Brice M; Millet, Maurice

    2015-01-01

    A method coupling thermal desorption and gas chromatography/mass spectrometry (GC/MS) was developed for the simultaneous determination of 7 pyrethroids (allethrin, bifenthrin, cyphenothrin, imiprothrin, permethrin, prallethrin and tetramethrin) and piperonyl butoxide adsorbed on Tenax TA(®) passive samplers after exposure in indoor air. Thermal desorption was selected as it permits efficient and rapid extraction without solvent used together with a good sensitivity. Detection (S/N>3) and quantification (S/N>10) limits varied between 0.001 ng and 2.5 ng and between 0.005 and 10 ng respectively with a reproducibility varied between 14% (bifenthrin) and 39% (permethrin). The method was used for the comparison indoor air contamination after low-pressure spraying and fumigation application in a rubbish chute situated in the basement of a building.

  17. Monitoring of Hazardous Air Pollutant Surrogates Using Resonance Enhanced Multiphoton Ionization/Time of Flight Mass Spectrometry

    EPA Science Inventory

    EPA’s preferred approach for regulatory emissions compliance is based upon real-time monitoring of individual hazardous air pollutants (HAPs). Real-time, continuous monitoring not only provides the most comprehensive assurance of emissions compliance, but also can serve as...

  18. Determination of Hazardous Air Pollutant Surrogates Using Resonance Enhanced Multi Photon Ionization - Time of Flight Mass Spectrometry

    EPA Science Inventory

    EPA?s preferred approach for regulatory emissions compliance is based upon real-time monitoring of individual hazardous air pollutants (HAPs). Real-time, continuous monitoring not only provides the most comprehensive assurance of emissions compliance, but also can serve as a pro...

  19. Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

    NASA Astrophysics Data System (ADS)

    Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

    2016-05-01

    A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes

  20. Light extinction by fine atmospheric particles in the White Mountains region of New Hampshire and its relationship to air mass transport.

    PubMed

    Slater, John F; Dibb, Jack E; Keim, Barry D; Talbot, Robert W

    2002-03-27

    Chemical, optical, and physical measurements of fine aerosols (aerodynamic diameter < or = 2.5 microm) have been performed at a mountaintop location adjacent to the White Mountain National Forest in northern NH, USA. A 1-month long sampling campaign was conducted at Cranmore Mountain during spring 2000. We report on the apportionment of light extinction by fine aerosols into its major chemical components, and relationships between variations in aerosol parameters and changes in air mass origin. Filter-based, 24-h integrated samples were collected and analyzed for major inorganic ions, as well as organic (OC), elemental (EC), and total carbon. Light scattering and light absorption coefficients were measured at 5-min intervals using an integrating nephelometer and a light absorption photometer. Fine particle number density was measured with a condensation particle counter. Air mass origins and transport patterns were investigated through the use of 3-day backward trajectories and a synoptic climate classification system. Two distinct transport regimes were observed: (1) flow from the north/northeast (N/NE) occurred during 9 out of 18 sample-days; and (2) flow from the west/southwest (W/SW) occurred 8 out of 18 sample-days. All measured and derived aerosol and meteorological parameters were separated into two categories based on these different flow scenarios. During W/SW flow, higher values of aerosol chemical concentration, absorption and scattering coefficients, number density, and haziness were observed compared to N/NE flow. The highest level of haziness was associated with the climate classification Frontal Atlantic Return, which brought polluted air into the region from the mid-Atlantic corridor. Fine particle mass scattering efficiencies of (NH4)2SO4 and OC were 5.35 +/- 0.42 m2 g(-1) and 1.56 +/- 0.40 m2 g(-1), respectively, when transport was out of the N/NE. When transport was from the W/SW the values were 4.94 +/- 0.68 m2 g(-1) for (NH4)2SO4 and 2.18 +/- 0

  1. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    NASA Technical Reports Server (NTRS)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  2. Inter-annual variability of air mass and acidified pollutants transboundary exchange in the north-eastern part of the EANET region

    NASA Astrophysics Data System (ADS)

    Gromov, Sergey A.; Trifonova-Yakovleva, Alisa; Gromov, Sergey S.

    2016-04-01

    Anthropogenic emissions, be it exhaust gases or aerosols, stem from multitude of sources and may survive long-range transport within the air masses they were emitted into. So they follow regional and global transport pathways varying under different climatological regimes. Transboundary transfer of pollutants occurs this way and has a significant impact on the ecological situation of the territories neighbouring those of emission sources, as found in a few earlier studies examining the environmental monitoring data [1]. In this study, we employ a relatively facile though robust technique for estimating the transboundary air and concomitant pollutant fluxes using actual or climatological meteorological and air pollution monitoring data. Practically, we assume pollutant transfer being proportional to the horizontal transport of air enclosed in the lower troposphere and to the concentration of the pollutant of interest. The horizontal transport, in turn, is estimated using the mean layer wind direction and strength, or their descriptive statistics at the individual transects of the boundary of interest. The domain of our interest is the segment of Russian continental border in East Asia spanning from 88° E (southern Middle Siberia) to 135° E (Far East at Pacific shore). The data on atmospheric pollutants concentration are available from the Russian monitoring sites of the region-wide Acid Deposition Monitoring Network in East Asia (EANET, http://www.eanet.asia/) Mondy (Baikal area) and Primorskaya (near Vladivostok). The data comprises multi-year continuous measurement of gas-phase and particulate species abundances in air with at least biweekly sampling rate starting from 2000. In the first phase of our study, we used climatological dataset on winds derived from the aerological soundings at Russian stations along the continental border for the 10-year period (1961-1970) by the Research Institute of Hydrometeorological Information - World Data Centre (RIHMI-WDC) [3

  3. Is PM(10) mass measurement a reliable index for air quality assessment? An environmental study in a geographical area of north-eastern Italy.

    PubMed

    Cozzi, F; Adami, G; Barbieri, P; Reisenhofer, E; Bovenzi, M

    2008-09-01

    The aim of this study was to measure the concentration of some metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Ti) in PM(10) samples collected in one urban and one industrial site and to assess that PM(10) total mass measurement may be not sufficient as air quality index due to its complex composition. Metals were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and differential pulsed anodic stripping voltammetry (DPASV). The measured concentrations were used to calculate the content of metals in the PM(10) total mass, and to estimate the enrichment factors and the correlations between PM(10), metal concentrations and meteorological data for the two sites. The mean PM10 concentration during the sampling period in the urban site exceeded the annual European Union (EU) standard (40 microg/m(3)) and, for some sampling days, the daily EU standard (50 microg/m(3)) was also exceeded. In opposite, both EU standards were never exceeded in the industrial site. The overall metal content was nearly double in the industrial site compared to the urban one, and the mean Ni concentration exceeded the EU annual limit value (10 ng/m(3)). The metals with the highest enrichment factor were Cd, Cu, Ni and Pb for both sites, suggesting a dominant anthropogenic source for these metals. Metal concentrations were very low and typical of rural background during Christmas holidays, when factories were closed. PM(10) total mass measurement is not a sufficient air quality index since the metal content of PM(10) is not related to its total mass, especially in sites with industrial activities. This measurement should be associated with the analysis of toxic metals.

  4. Apparatus Circulates Sterilizing Gas

    NASA Technical Reports Server (NTRS)

    Cross, John H.; Schwarz, Ray P.

    1991-01-01

    Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

  5. Convergent crater circulations on Mars: Influence on the surface pressure cycle and the depth of the convective boundary layer

    NASA Astrophysics Data System (ADS)

    Tyler, Daniel; Barnes, Jeffrey R.

    2015-09-01

    Modeling of slope flow circulations in idealized axisymmetric craters is used to understand (1) the large surface pressure amplitude observed in Gale Crater by the Rover Environmental Monitoring Station and (2) the shallow convective boundary layer (CBL) suggested by Curiosity imagery. Air temperatures vary within craters with greater amplitudes than outside them, becoming warmer/colder during day/night. This crater circulation effect is most significant over the depth of the crater (key parameter). Within the idealized craters, a surface pressure cycle develops (in the real atmosphere it is enhanced). Partially caused by thermal expansion, a "surge" of mass away from the craters develops during daytime. Over crater floors, the CBL depth is inhibited by a capping inversion from the adiabatic warming of widespread daytime subsidence. For a variety of craters (radius, depth, and with or without a central mound), the results are very similar. In real-atmosphere simulations over canyons or large basins, similar circulations are seen.

  6. Sensitive indoor air monitoring of monoterpenes using different adsorbents and thermal desorption gas chromatography with mass-selective detection.

    PubMed

    Hollender, Juliane; Sandner, Frank; Möller, Manfred; Dott, Wolfgang

    2002-07-12

    A simple method using active trapping on adsorbents and thermal desorption followed by GC-MS analysis was developed for the indoor air monitoring of monoterpenes. The study was carried out using a dynamically generated atmosphere consisting of 11 monoterpenes: camphene, camphor, delta 3-carene, 1,8-cineol, limonene, linalool, alpha-pinene, beta-pinene, alpha-terpinene, gamma-terpinene, fenchyl alcohol. The influence of the different adsorbents Tenax TA, Tenax GR, Carbosieve SIII, Chromosorb 106 on the yield of six selected monoterpenes at indoor air concentrations was studied. The adsorbent Tenax GR gave relatively the best yields followed by Tenax TA. Detection limits of approximately 1 microgram m3 were determined with Tenax GR for most of the monoterpenes.

  7. Ocean circulation and climate change

    NASA Astrophysics Data System (ADS)

    Hasselmann, Klaus

    1991-09-01

    Recent numerical simulations using global ocean circulation models are reviewed together with model experiments involving further important climate sub-systems with which the ocean interacts: the atmosphere, the air-sea interface and the global carbon cycle. A common feature of all ocean circulation experiments considered is the strong sensitivity of the circulation to relatively minor changes in surface forcing, particularly to the buoyancy fluxes in regions of deep water formation in high latitudes. This may explain some of the well-known deficiencies of past global ocean circulation simulations. The strong sensitivity may also have been the cause of rapid climate changes observed in paleoclimatic records and can lead further to significant natural climate variability on the time scales of a few hundred years through the stochastic forcing of the ocean by atmospheric weather variability. Gobal warming computations using two different coupled ocean-atmosphere models for the "business-as-usual" scenario of the Intergovernmental Panel on Climate Change yield a significantly stronger warming delay due to the heat uptake by the oceans in the Southern Ocean than estimated on the basis of box-diffusion models. Recent advances in surface wave modelling, illustrated by a comparison of wave height fields derived from the WAM model and the GEOSAT altimeter, hold promise for the development of an improved representation of ocean-atmosphere coupling based on an explicit description of the dynamical processes at the air-sea interface. Global carbon cycle simulations with a three dimensional carbon cycle model tuned to reproduce past variations of carbon cycle indices show a significant impact of variations in the ocean circulation on the CO2 concentration in the atmosphere and thereby on climate. The series of experiments suggest that for the study of climate in the time scale range from 10-Ocean circulation and climate change

    NASA Astrophysics Data System (ADS)

    Hasselmann, Klaus

    1991-08-01

    Recent numerical simulations using global ocean circulation models are reviewed together with model experiments involving further important climate sub-systems with which the ocean interacts: the atmosphere, the air-sea interface and the global carbon cycle. A common feature of all ocean circulation experiments considered is the strong sensitivity of the circulation to relatively minor changes in surface forcing, particularly to the buoyancy fluxes in regions of deep water formation in high latitudes. This may explain some of the well-known deficiencies of past global ocean circulation simulations. The strong sensitivity may also have been the cause of rapid climate changes observed in paleoclimatic records and can lead further to significant natural climate variability on the time scales of a few hundred years through the stochastic forcing of the ocean by atmospheric weather variability. Gobal warming computations using two different coupled ocean-atmosphere models for the "business-as-usual" scenario of the Intergovernmental Panel on Climate Change yield a significantly stronger warming delay due to the heat uptake by the oceans in the Southern Ocean than estimated on the basis of box-diffusion models. Recent advances in surface wave modelling, illustrated by a comparison of wave height fields derived from the WAM model and the GEOSAT altimeter, hold promise for the development of an improved representation of ocean-atmosphere coupling based on an explicit description of the dynamical processes at the air-sea interface. Global carbon cycle simulations with a three dimensional carbon cycle model tuned to reproduce past variations of carbon cycle indices show a significant impact of variations in the ocean circulation on the CO2 concentration in the atmosphere and thereby on climate. The series of experiments suggest that for the study of climate in the time scale range from 10-Occupational Exposure to Cobalt and Tungsten in the Swedish Hard Metal Industry: Air Concentrations of Particle Mass, Number, and Surface Area

    PubMed Central

    Bryngelsson, Ing-Liss; Pettersson, Carin; Husby, Bente; Arvidsson, Helena; Westberg, Håkan

    2016-01-01

    Exposure to cobalt in the hard metal industry entails severe adverse health effects, including lung cancer and hard metal fibrosis. The main aim of this study was to determine exposure air concentration levels of cobalt and tungsten for risk assessment and dose–response analysis in our medical investigations in a Swedish hard metal plant. We also present mass-based, particle surface area, and particle number air concentrations from stationary sampling and investigate the possibility of using these data as proxies for exposure measures in our study. Personal exposure full-shift measurements were performed for inhalable and total dust, cobalt, and tungsten, including personal real-time continuous monitoring of dust. Stationary measurements of inhalable and total dust, PM2.5, and PM10 was also performed and cobalt and tungsten levels were determined, as were air concentration of particle number and particle surface area of fine particles. The personal exposure levels of inhalable dust were consistently low (AM 0.15mg m−3, range <0.023–3.0mg m−3) and below the present Swedish occupational exposure limit (OEL) of 10mg m−3. The cobalt levels were low as well (AM 0.0030mg m−3, range 0.000028–0.056mg m−3) and only 6% of the samples exceeded the Swedish OEL of 0.02mg m−3. For continuous personal monitoring of dust exposure, the peaks ranged from 0.001 to 83mg m−3 by work task. Stationary measurements showed lower average levels both for inhalable and total dust and cobalt. The particle number concentration of fine particles (AM 3000 p·cm−3) showed the highest levels at the departments of powder production, pressing and storage, and for the particle surface area concentrations (AM 7.6 µm2·cm−3) similar results were found. Correlating cobalt mass-based exposure measurements to cobalt stationary mass-based, particle area, and particle number concentrations by rank and department showed significant correlations for all measures except for particle

  8. Desert Dust Air Mass Mapping in the Western Sahara, using Particle Properties Derived from Space-based Multi-angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Fiebig, Marcus; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the SAhara Mineral dUst experiMent (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from Multi-angle Imaging SpectroRadiometer (MISR) observations, and to place the sub-orbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days for which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 to 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR's ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape, and single-scattering albedo. For the three study days, the satellite observations (a) highlight regional gradients in the mix of dust and background spherical particles, (b) identify a dust plume most likely part of a density flow, and (c) show an air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometers away.

  9. Quantification of VX vapor in ambient air by liquid chromatography isotope dilution tandem mass spectrometric analysis of glass bead filled sampling tubes.

    PubMed

    Evans, Ronald A; Smith, Wendy L; Nguyen, Nam-Phuong; Crouse, Kathy L; Crouse, Charles L; Norman, Steven D; Jakubowski, E Michael

    2011-02-15

    An analysis method has been developed for determining low parts-per-quadrillion by volume (ppqv) concentrations of nerve agent VX vapor actively sampled from ambient air. The method utilizes glass bead filled depot area air monitoring system (DAAMS) sampling tubes with isopropyl alcohol extraction and isotope dilution using liquid chromatography coupled with a triple-quadrupole mass spectrometer (LC/MS/MS) with positive ion electrospray ionization for quantitation. The dynamic range was from one-tenth of the worker population limit (WPL) to the short-term exposure limit (STEL) for a 24 L air sample taken over a 1 h period. The precision and accuracy of the method were evaluated using liquid-spiked tubes, and the collection characteristics of the DAAMS tubes were assessed by collecting trace level vapor generated in a 1000 L continuous flow chamber. The method described here has significant improvements over currently employed thermal desorption techniques that utilize a silver fluoride pad during sampling to convert VX to a higher volatility G-analogue for gas chromatographic analysis. The benefits of this method are the ability to directly analyze VX with improved selectivity and sensitivity, the injection of a fraction of the extract, quantitation using an isotopically labeled internal standard, and a short instrument cycle time.

  10. Numerical Model Studies of the Martian Mesoscale Circulations

    NASA Technical Reports Server (NTRS)

    Segal, M.; Arritt, R. W.

    1996-01-01

    Studies concerning mesoscale topographical effects on Martian flows examined low-level jets in the near equatorial latitudes and the dynamical intensification of flow by steep terrain. Continuation of work from previous years included evaluating the dissipation of cold air mass outbreaks due to enhanced sensible heat flux, further sensitivity and scaling evaluations for generalization of the characteristics of Martian mesoscale circulation caused by horizontal sensible heat-flux gradients, and evaluations of the significance that non-uniform surface would have on enhancing the polar CO2 ice sublimation during the spring. The sensitivity of maximum and minimum atmospheric temperatures to changes in wind speed, surface albedo, and deep soil temperature was investigated.

  11. Comparative metabolomics analysis on invigorating blood circulation for herb pair Gui-Hong by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry and pattern recognition approach.

    PubMed

    Li, Shujiao; Lin, Hang; Tang, Yuping; Li, Weixia; Shen, Juan; Kai, Jun; Yue, Shijun; Shang, Guanxiong; Zhu, Zhenhua; Shang, Erxin; Zhang, Changbin; Zhang, Li; Yan, Hui; Liu, Pei; Duan, Jin-ao

    2015-03-25

    The compatibility of Angelicae Sinensis Radix (Danggui, DG) and Flos Carthami (Honghua, HH), a famous herb pair Gui-Hong (GH), can produce synergistic and promoting blood effects. Although some physiological and pathological function parameters of the acute blood stasis have been investigated, little information about the changes of small metabolites in biofluids has been reported. In present study, global metabolic profiling with ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) combined with pattern recognition method was performed to discover the underlying blood-activating regulation mechanisms of DG, HH and GH on the acute blood stasis rats induced by subcutaneous injection of adrenaline hydrochloride and ice water bath. The total 14 metabolites (10 in urine and 4 in plasma), up regulated or down regulated (P<0.05 or 0.01), were identified and contributed to the acute blood stasis progress. These promising identified biomarkers underpin the metabolic pathway including phenylalanine metabolism, sphingolipid metabolism, arachidonic acid metabolism and arginine and proline metabolism are disturbed in the acute blood stasis rats, which identified by using pathway analysis with MetPA. The altered metabolites and hemorheological indexes could be regulated closer to normal level after DG, HH and GH intervention. In term of activate blood circulation function, GH was the most effective as shown by the relative distance in PLS-DA score plots and relative intensity of metabolomics trategy, reflecting the synergic action between Danggui and Honghua. The results demonstrated that biofluids metabolomics was a powerful tool in clinical diagnosis and treatment of syndrome of blood stasis for providing information on changes in metabolites pathways. PMID:25668798

  12. Student Understanding of the Volume, Mass, and Pressure of Air within a Sealed Syringe in Different States of Compression.

    ERIC Educational Resources Information Center

    de Berg, Kevin Charles

    1995-01-01

    Investigation of (n=101) 17- to 18-year-old students' responses to a task relating to Boyle's Law for gases found that 34% to 38% of students did not understand the concepts of volume and mass, respectively, of a gas under the given circumstances. (Author/MKR)

  13. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry.

    PubMed

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH(+), MOH(+), and MO(2)H(+), respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH(+) sharply decreased, that of MOH(+) increased once and then decreased, and that of MO(2)H(+) sharply increased until reaching a plateau. The signal intensity of MO(2)H(+) at the plateau was 40 times higher than that of MH(+) and 100 times higher than that of MOH(+) in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO(2)H(+) signal in the concentration range up to 60 μg/m(3), which is high enough for hygiene management. In the low concentration range lower than 3 μg/m(3), which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-μg/m(3) vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  14. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH+, MOH+, and MO2H+, respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH+ sharply decreased, that of MOH+ increased once and then decreased, and that of MO2H+ sharply increased until reaching a plateau. The signal intensity of MO2H+ at the plateau was 40 times higher than that of MH+ and 100 times higher than that of MOH+ in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO2H+ signal in the concentration range up to 60 μg/m3, which is high enough for hygiene management. In the low concentration range lower than 3 μg/m3, which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-μg/m3 vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  15. Climatological classification of five sectors in the Iberian Peninsula using columnar (AOD, α) and surface (PM10, PM2.5) aerosol data supported by air mass apportioning

    NASA Astrophysics Data System (ADS)

    Cachorro, Victoria; Mateos, David; Toledano, Carlos; Burgos, Maria A.; Bennouna, Yasmine; Torres, Benjamín; Fuertes, David; González, Ramiro; Guirado, Carmen; Román, Roberto; Velasco-Merino, Cristian; Marcos, Alberto; Calle, Abel; de Frutos, Angel M.

    2015-04-01

    The study of atmospheric aerosol over the Iberian Peninsula (IP) under a climatologic perspective is an interesting and meaningful aim due to the wide variety of conditions (geographical position, air masses, topography, among others) which cause a complex role of the distribution of aerosol properties. In the deeply investigation on the annual cycle and time evolution of the particulate matter lower than 10 µm (PM10, surface) and aerosol optical depth (AOD, columnar) in a large number of sites covering the period 2000-2013, five sectors can be distinguished in the IP. Both set of data belong to EMEP and AERONET networks respectively, as representative of aerosol air quality and climate studies, are complementary elements for a global aerosol research. The prevalence of fine-coarse particles is also analyzed over each sector. Seasonal bimodality of the PM10 annual cycle with a strong North-South gradient is observed in most sites, but this is only reported in the AOD climatology for the southern IP. The northern coast is clearly governed by the Atlantic Ocean influence, while the northeastern area is modulated by the Mediterranean Sea. The southern area, very close to the African continent, presents a large influence of desert dust intrusions. However, the southern Atlantic and Mediterranean coast present discrepancies and two sectors have been defined in this area. Finally, the center of the Peninsula is a mix of conditions, with north-south and east-west gradients of different magnitude. Overall, there is a relationship between PM10 and AOD with a proportional factor varying from 20 to 90, depending on the sector. The particular characteristic of PM10-AOD annual cycle of each geographical sector can be understood by the different climatology of the air mass origins observed at 500 and 1500 m (a.s.l.) and its apportioning to PM10 and AOD, respectively.

  16. Back-trajectory modelling and DNA-based species-specific detection methods allow tracking of fungal spore transport in air masses.

    PubMed

    Grinn-Gofroń, Agnieszka; Sadyś, Magdalena; Kaczmarek, Joanna; Bednarz, Aleksandra; Pawłowska, Sylwia; Jedryczka, Malgorzata

    2016-11-15

    Recent advances in molecular detection of living organisms facilitate the introduction of novel methods to studies of the transport of fungal spores over large distances. Monitoring the migration of airborne fungi using microscope based spore identification is limited when different species produce very similar spores. In our study, DNA-based monitoring with the use of species-specific probes allowed us to track the aerial movements of two important fungal pathogens of oilseed rape (Brassica napus L.), i.e., Leptosphaeria maculans and Leptosphaeria biglobosa, which have identical spore shape and size. The fungi were identified using dual-labelled fluorescent probes that were targeted to a β-tubulin gene fragment of either Leptosphaeria species. Spore identification by Real-Time PCR techniques capable of detecting minute amounts of DNA of selected fungal species was combined with back-trajectory analysis, allowing the tracking of past movements of air masses using the Hybrid Single Particle Lagrangian Integrated Trajectory model. Over a study period spanning the previous decade (2006-2015) we investigated two specific events relating to the long distance transport of Leptosphaeria spp. spores to Szczecin in North-West Poland. Based on the above mentioned methods and the results obtained with the additional spore sampler located in nearby Szczecin, and operating at the ground level in an oilseed rape field, we have demonstrated that on both occasions the L. biglobosa spores originated from the Jutland Peninsula. This is the first successful attempt to combine analysis of back-trajectories of air masses with DNA-based identification of economically important pathogens of oilseed rape in Europe. In our studies, the timing of L. biglobosa ascospore dispersal in the air was unlikely to result in the infection of winter oilseed rape grown as a crop plant. However, the fungus could infect other host plants, such as vegetable brassicas, cruciferous weeds, spring rapeseed

  17. Back-trajectory modelling and DNA-based species-specific detection methods allow tracking of fungal spore transport in air masses.

    PubMed

    Grinn-Gofroń, Agnieszka; Sadyś, Magdalena; Kaczmarek, Joanna; Bednarz, Aleksandra; Pawłowska, Sylwia; Jedryczka, Malgorzata

    2016-11-15

    Recent advances in molecular detection of living organisms facilitate the introduction of novel methods to studies of the transport of fungal spores over large distances. Monitoring the migration of airborne fungi using microscope based spore identification is limited when different species produce very similar spores. In our study, DNA-based monitoring with the use of species-specific probes allowed us to track the aerial movements of two important fungal pathogens of oilseed rape (Brassica napus L.), i.e., Leptosphaeria maculans and Leptosphaeria biglobosa, which have identical spore shape and size. The fungi were identified using dual-labelled fluorescent probes that were targeted to a β-tubulin gene fragment of either Leptosphaeria species. Spore identification by Real-Time PCR techniques capable of detecting minute amounts of DNA of selected fungal species was combined with back-trajectory analysis, allowing the tracking of past movements of air masses using the Hybrid Single Particle Lagrangian Integrated Trajectory model. Over a study period spanning the previous decade (2006-2015) we investigated two specific events relating to the long distance transport of Leptosphaeria spp. spores to Szczecin in North-West Poland. Based on the above mentioned methods and the results obtained with the additional spore sampler located in nearby Szczecin, and operating at the ground level in an oilseed rape field, we have demonstrated that on both occasions the L. biglobosa spores originated from the Jutland Peninsula. This is the first successful attempt to combine analysis of back-trajectories of air masses with DNA-based identification of economically important pathogens of oilseed rape in Europe. In our studies, the timing of L. biglobosa ascospore dispersal in the air was unlikely to result in the infection of winter oilseed rape grown as a crop plant. However, the fungus could infect other host plants, such as vegetable brassicas, cruciferous weeds, spring rapeseed

  18. Circulation control STOL aircraft design aspects

    NASA Technical Reports Server (NTRS)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  1. Lidar observations of ozone changes induced by subpolar air mass motion over Table Mountain, California (34.4 deg N)

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Newman, Paul; Ferrare, Richard; Whiteman, David; Burris, John; Butler, James; Godin, Sophie; Mcdermid, I. Stuart

    1990-01-01

    Between October 15 and November 8, 1988, the Goddard Space Flight Center mobile stratospheric lidar was in place at the (JPL) Table Mountain Facility (located at 34.4 deg N, 117.7 deg W) for the purpose of intercomparing with the JPL lidar permanently stationed at the observatory. During the course of the intercomparison both lidar systems detected a significant change in the vertical profile of ozone lasting for several days. An analysis of meteorological data available from the National Meteorological Center has shown this change to be dynamical in origin due to the transport of subpolar air over Table Mountain.

  2. Circulating omentin concentration increases after weight loss

    PubMed Central

    2010-01-01

    Background Omentin-1 is a novel adipokine expressed in visceral adipose tissue and negatively associated with insulin resistance and obesity. We aimed to study the effects of weight loss-induced improved insulin sensitivity on circulating omentin concentrations. Methods Circulating omentin-1 (ELISA) concentration in association with metabolic variables was measured in 35 obese subjects (18 men, 17 women) before and after hypocaloric weight loss. Results Baseline circulating omentin-1 concentrations correlated negatively with BMI (r = -0.58, p < 0.001), body weight (r = -0.35, p = 0.045), fat mass (r = -0.67, p < 0.001), circulating leptin (r = -0.7, p < 0.001) and fasting insulin (r = -0.37, p = 0.03). Circulating omentin-1 concentration increased significantly after weight loss (from 44.9 ± 9.02 to 53.41 ± 8.8 ng/ml, p < 0.001). This increase in circulating omentin after weight loss was associated with improved insulin sensitivity (negatively associated with HOMA value and fasting insulin, r = -0.42, p = 0.02 and r = -0.45, p = 0.01, respectively) and decreased BMI (r = -0.54, p = 0.001). Conclusion As previously described with adiponectin, circulating omentin-1 concentrations increase after weight loss-induced improvement of insulin sensitivity. PMID:20380714

  3. Interannual variability of the Adriatic Sea circulation

    NASA Astrophysics Data System (ADS)

    Beg Paklar, Gordana; Sepic, Jadranka; Grbec, Branka; Dzoic, Tomislav; Kovac, Zarko; Ivatek-Sahdan, Stjepan

    2016-04-01

    The Regional Ocean Modeling System (ROMS) was implemented in order to reproduce interannual variability of the Adriatic Sea circulation. Simulations and model result analysis were performed for a three-year period from 1st January 2011 to 31st December 2013. ROMS model run was forced with realistic atmospheric fields obtained from meteorological model Aladin, climatological river discharges, tides and Mediterranean circulation imposed at the southern open boundary. Atmospheric forcing included momentum, heat and water fluxes calculated interactively from the Aladin surface fields during ROMS model simulations. Model results were compared with available CTD and ADCP measurements and discussed in the light of the climatological circulation and thermohaline properties of the Adriatic Sea and its coastal areas. Interannual variability in the Adriatic circulation is related to the prevailing atmospheric conditions, changes in the hydrological conditions and water mass exchange at the Otranto Strait. Basic features of the Adriatic circulation - basin-wide cyclonic circulation with several embedded smaller cyclonic gyres around main pits - are well reproduced by ROMS model. Modelled temperatures and salinities are within corresponding seasonal intervals, although measured profiles generally indicate stronger stratification than modelled ones. Summer circulation in 2011 with current reversal obtained along the eastern Adriatic coast was related to the sampling results of the early fish stages as well as to ARGO drifter movements. Simulated fields from the Adriatic scale model were used to prescribe the initial and open boundary conditions for the interannual simulation in the middle Adriatic coastal domain.

  4. Associations between Prenatal traffic-related air pollution exposure and birth weight: Modification by sex and maternal pre-pregnancy body mass index

    PubMed Central

    Coull, Brent A.; Just, Allan C.; Maxwell, Sarah L.; Schwartz, Joel; Gryparis, Alexandros; Kloog, Itai; Wright, Rosalind J.; Wright, Robert O.

    2015-01-01

    Background Prenatal traffic-related air pollution exposure is linked to adverse birth outcomes. However, modifying effects of maternal body mass index (BMI) and infant sex remain virtually unexplored. Objectives We examined whether associations between prenatal air pollution and birth weight differed by sex and maternal BMI in 670 urban ethnically mixed mother-child pairs. Methods Black carbon (BC) levels were estimated using a validated spatio-temporal land-use regression (LUR) model; fine particulate matter (PM2.5) was estimated using a hybrid LUR model incorporating satellite-derived Aerosol Optical Depth measures. Using stratified multivariable-adjusted regression analyses, we examined whether associations between prenatal air pollution and calculated birth weight for gestational age (BWGA) z-scores varied by sex and maternal pre-pregnancy BMI. Results Median birth weight was 3.3±0.6 kg; 33% of mothers were obese (BMI ≥30 kg/m3). In stratified analyses, the association between higher PM2.5 and lower birth weight was significant in males of obese mothers (−0.42 unit of BWGA z-score change per IQR increase in PM2.5, 95%CI: −0.79 to −0.06) ( PM2.5 × sex × obesity Pinteraction=0.02). Results were similar for BC models (Pinteraction=0.002). Conclusions Associations of prenatal exposure to traffic-related air pollution and reduced birth weight were most evident in males born to obese mothers. PMID:25601728

  5. Mass of chlorinated volatile organic compounds removed by Pump-and-Treat, Naval Air Warfare Center, West Trenton, New Jersey, 1996-2010

    USGS Publications Warehouse

    Lacombe, Pierre J.

    2011-01-01

    Pump and Treat (P&T) remediation is the primary technique used to contain and remove trichloroethylene (TCE) and its degradation products cis 1-2,dichloroethylene (cDCE) and vinyl chloride (VC) from groundwater at the Naval Air Warfare Center (NAWC), West Trenton, NJ. Three methods were used to determine the masses of TCE, cDCE, and VC removed from groundwater by the P&T system since it became fully operational in 1996. Method 1, is based on the flow volume and concentrations of TCE, cDCE, and VC in groundwater that entered the P&T building as influent. Method 2 is based on withdrawal volume from each active recovery well and the concentrations of TCE, cDCE, and VC in the water samples from each well. Method 3 compares the maximum monthly amount of TCE, cDCE, and VC from Method 1 and Method 2. The greater of the two values is selected to represent the masses of TCE, cDCE and VC removed from groundwater each month. Previously published P&T monthly reports used Method 1 to determine the mass of TCE, cDCE, and VC removed. The reports state that 8,666 pounds (lbs) of TCE, 13,689 lbs of cDCE, and 2,455 lbs of VC were removed by the P&T system during 1996-2010. By using Method 2, the mass removed was determined to be 8,985 lbs of TCE, 17,801 lbs of cDCE, and 3,056 lbs of VC removed, and Method 3, resulted in 10,602 lbs of TCE, 21,029 lbs of cDCE, and 3,496 lbs of VC removed. To determine the mass of original TCE removed from groundwater, the individual masses of TCE, cDCE, and VC (determined using Methods 1, 2, and 3) were converted to numbers of moles, summed, and converted to pounds of original TCE. By using the molar conversion the mass of original TCE removed from groundwater by Methods 1, 2, and 3 was 32,381 lbs, 39,535 lbs, and 46,452 lbs, respectively, during 1996-2010. P&T monthly reports state that 24,805 lbs of summed TCE, cDCE, and VC were removed from groundwater. The simple summing method underestimates the mass of original TCE removed by the P&T system.

  6. Dynamic behavior of air lubricated pivoted-pad journal-bearing, rotor system. 2: Pivot consideration and pad mass

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1972-01-01

    Rotor bearing dynamic tests were conducted with tilting-pad journal bearings having three different pad masses and two different pivot geometries. The rotor was vertically mounted and supported by two three-pad tilting-pad gas journal bearings and a simple externally pressurized thrust bearing. The bearing pads were 5.1 cm (2.02 in.) in diameter and 2.8 cm (1.5 in.) long. The length to diameter ratio was 0.75. One pad was mounted on a flexible diaphragm. The bearing supply pressure ranged from 0 to 690 kilonewtons per square meter (0 to 100 psig), and speeds ranged to 38,500 rpm. Heavy mass pad tilting-pad assemblies produced three rotor-bearing resonances above the first two rotor critical speeds. Lower supply pressure eliminated the resonances. The resonances were oriented primarily in the direction normal to the diaphragm.

  7. Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters

    SciTech Connect

    Smith, Brian M.; Barnett, J. Matthew; Ballinger, Marcel Y.

    2011-01-18

    This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

  8. Two-dimensional two-phase mass transport model for methanol and water crossover in air-breathing direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Ye, Dingding; Zhu, Xun; Liao, Qiang; Li, Jun; Fu, Qian

    A two-dimensional two-phase mass transport model has been developed to predict methanol and water crossover in a semi-passive direct methanol fuel cell with an air-breathing cathode. The mass transport in the catalyst layer and the discontinuity in liquid saturation at the interface between the diffusion layer and catalyst layer are particularly considered. The modeling results agree well with the experimental data of a home-assembled cell. Further studies on the typical two-phase flow and mass transport distributions including species, pressure and liquid saturation in the membrane electrode assembly are investigated. Finally, the methanol crossover flux, the net water transport coefficient, the water crossover flux, and the total water flux at the cathode as well as their contributors are predicted with the present model. The numerical results indicate that diffusion predominates the methanol crossover at low current densities, while electro-osmosis is the dominator at high current densities. The total water flux at the cathode is originated primarily from the water generated by the oxidation reaction of the permeated methanol at low current densities, while the water crossover flux is the main source of the total water flux at high current densities.

  9. Direct AFM force measurements between air bubbles in aqueous polydisperse sodium poly(styrene sulfonate) solutions: effect of collision speed, polyelectrolyte concentration and molar mass.

    PubMed

    Browne, Christine; Tabor, Rico F; Grieser, Franz; Dagastine, Raymond R

    2015-07-01

    Interactions between colliding air bubbles in aqueous solutions of polydisperse sodium poly(styrene sulfonate) (NaPSS) using direct force measurements were studied. The forces measured with deformable interfaces were shown to be more sensitive to the presence of the polyelectrolytes when compared to similar measurements using rigid interfaces. The experimental factors that were examined were NaPSS concentration, bubble collision velocity and polyelectrolyte molar mass. These measurements were then compared with an analytical model based on polyelectrolyte scaling theory in order to explain the effects of concentration and bubble deformation on the interaction between bubbles. Typically structural forces from the presence of monodisperse polyelectrolyte between interacting surfaces may be expected, however, it was found that the polydispersity in molar mass resulted in the structural forces to be smoothed and only a depletion interaction was able to be measured between interacting bubbles. It was found that an increase in number density of NaPSS molecules resulted in an increase in the magnitude of the depletion interaction. Conversely this interaction was overwhelmed by an increase in the fluid flow in the system at higher bubble collision velocities. Polymer molar mass dispersity plays a significant role in the interactions present between the bubbles and has implications that also affect the polyelectrolyte overlap concentration of the solution. Further understanding of these implications can be expected to play a role in the improvement in operations in such fields as water treatment and mineral processing where polyelectrolytes are used extensively.

  10. Determining air pollutant emission rates based on mass balance using airborne measurement data over the Alberta oil sands operations

    NASA Astrophysics Data System (ADS)

    Gordon, M.; Li, S.-M.; Staebler, R.; Darlington, A.; Hayden, K.; O'Brien, J.; Wolde, M.

    2015-09-01

    Top-down approaches to measure total integrated emissions provide verification of bottom-up, temporally resolved, inventory-based estimations. Aircraft-based measurements of air pollutants from sources in the Canadian oil sands were made in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring during a summer intensive field campaign between 13 August and 7 September 2013. The measurements contribute to knowledge needed in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring. This paper describes the top-down emission rate retrieval algorithm (TERRA) to determine facility emissions of pollutants, using SO2 and CH4 as examples, based on the aircraft measurements. In this algorithm, the flight path around a facility at multiple heights is mapped to a two-dimensional vertical screen surrounding the facility. The total transport of SO2 and CH4 through this screen is calculated using aircraft wind measurements, and facility emissions are then calculated based on the divergence theorem with estimations of box-top losses, horizontal and vertical turbulent fluxes, surface deposition, and apparent losses due to air densification and chemical reaction. Example calculations for two separate flights are presented. During an upset condition of SO2 emissions on one day, these calculations are within 5 % of the industry-reported, bottom-up measurements. During a return to normal operating conditions, the SO2 emissions are within 11 % of industry-reported, bottom-up measurements. CH4 emissions calculated with the algorithm are relatively constant within the range of uncertainties. Uncertainty of the emission rates is estimated as less than 30 %, which is primarily due to the unknown SO2 and CH4 mixing ratios near the surface below the lowest flight level.

  11. Flapping Wing Micro Air Vehicles: An Analysis of the Importance of the Mass of the Wings to Flight Dynamics, Stability, and Control

    NASA Astrophysics Data System (ADS)

    Orlowski, Christopher T.

    The flight dynamics, stability, and control of a model flapping wing micro air vehicle are analyzed with a focus on the inertial and mass effects of the wings on the position and Orientation of the body. A multi-body, flight dynamics model is derived from first principles. The multi-body model predicts significant differences in the position and orientation of the flapping wing micro air vehicle, when compared to a flight dynamics model based on the standard aircraft, or six degree of freedom, equations of motion. The strongly coupled, multi-body equations of motion are transformed into first order form using an approximate inverse and appropriate assumptions. Local (naive) averaging of the first order system does not produce an accurate result and a new approximation technique named 'quarter-cycle' averaging is proposed. The technique is effective in reducing the error by at least an order of magnitude for three reference flight conditions. A stability analysis of the local averaged equations of motions, in the vicinity of a hover condition, produces a modal structure consist with the most common vertical takeoff or landing structure and independent stability analyses of the linearized flight dynamics of insect models. The inclusion of the wing effects produces a non-negligible change in the linear stability of a hawkmoth-sized model. The hovering solution is shown, under proper control, to produce a limit cycle. The control input to achieve a limit cycle is different if the flight dynamics model includes the wing effects or does not include the wing effects. Improper control input application will not produce the desired limit cycle effects. A scaling analysis is used to analyze the relative importance of the mass of the wings, based on the quarter-cycle approximation. The conclusion of the scaling analysis is that the linear momentum effects of the wings are always important in terms of the inertial position of the flapping wing micro air vehicle. Above a

  12. Application of high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for determination of chromium compounds in the air at the workplace.

    PubMed

    Stanislawska, Magdalena; Janasik, Beata; Wasowicz, Wojciech

    2013-12-15

    The toxicity and bioavailability of chromium species are highly dependable on the form or species, therefore determination of total chromium is insufficient for a complete toxicological evaluation and risk assessment. An analytical method for determination of soluble and insoluble Cr (III) and Cr (VI) compounds in welding fume at workplace air has been developed. The total chromium (Cr) was determined by using quadruple inductively coupled plasma mass spectrometry (ICP-MS) equipped with a dynamic reaction cell (DRC(®)). Soluble trivalent and hexavalent chromium compounds were determined by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). A high-speed, reversed-phase CR C8 column (PerkinElmer, Inc., Shelton, CT, USA) was used for the speciation of soluble Cr (III) and soluble Cr (VI). The separation was accomplished by interaction of the chromium species with the different components of the mobile phase. Cr (III) formed a complex with EDTA, i.e. retained on the column, while Cr (VI) existed in the solutions as dichromate. Alkaline extraction (2% KOH and 3% Na2CO3) and anion exchange column (PRP-X100, PEEK, Hamilton) were used for the separation of the total Cr (VI). The results of the determination of Cr (VI) were confirmed by the analysis of the certified reference material BCR CRM 545 (Cr (VI) in welding dust). The results obtained for the certified material (40.2±0.6 g kg(-1)) and the values recorded in the examined samples (40.7±0.6 g kg(-1)) were highly consistent. This analytical method was applied for the determination of chromium in the samples in the workplace air collected onto glass (Whatman, Ø 37 mm) and membrane filters (Sartorius, 0.8 μm, Ø 37 mm). High performance liquid chromatography with inductively coupled plasma mass spectrometry is a remarkably powerful and versatile technique for determination of chromium species in welding fume at workplace air. PMID:24209303

  13. Detecting holocene changes in thermohaline circulation.

    PubMed

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous. PMID:10677463

  14. Detecting Holocene changes in thermohaline circulation

    PubMed Central

    Keigwin, L. D.; Boyle, E. A.

    2000-01-01

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous. PMID:10677463

  15. Detecting holocene changes in thermohaline circulation.

    PubMed

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  16. Development and Evaluation of an Externally Air-Cooled Low-Flow torch and the Attenuation of Space Charge and Matrix Effects in Inductively Coupled Plasma Mass Spectrometry

    SciTech Connect

    Praphairaksit, N.

    2000-09-12

    An externally air-cooled low-flow torch has been constructed and successfully demonstrated for applications in inductively coupled plasma mass spectrometry (ICP-MS). The torch is cooled by pressurized air flowing at {approximately}70 L/min through a quartz air jacket onto the exterior of the outer tube. The outer gas flow rate and operating RF forward power are reduced considerably. Although plasmas can be sustained at the operating power as low as 400 W with a 2 L/min of outer gas flow, somewhat higher power and outer gas flows are advisable. A stable and analytical useful plasma can be obtained at 850 W with an outer gas flow rate of {approximately}4 L/min. Under these conditions, the air-cooled plasma produces comparable sensitivities, doubly charged ion ratios, matrix effects and other analytical merits as those produced by a conventional torch while using significantly less argon and power requirements. Metal oxide ion ratios are slightly higher with the air-cooled plasma but can be mitigated by reducing the aerosol gas flow rate slightly with only minor sacrifice in analyte sensitivity. A methodology to alleviate the space charge and matrix effects in ICP-MS has been developed. A supplemental electron source adapted from a conventional electron impact ionizer is added to the base of the skimmer. Electrons supplied from this source downstream of the skimmer with suitable amount and energy can neutralize the positive ions in the beam extracted from the plasma and diminish the space charge repulsion between them. As a result, the overall ion transmission efficiency and consequent analyte ion sensitivities are significantly improved while other important analytical aspects, such as metal oxide ion ratio, doubly charged ion ratio and background ions remain relatively unchanged with the operation of this electron source. This technique not only improves the ion transmission efficiency but also minimizes the matrix effects drastically. The matrix-induced suppression

  17. A high-fidelity multiphysics model for the new solid oxide iron-air redox battery part I: Bridging mass transport and charge transfer with redox cycle kinetics

    SciTech Connect

    Jin, XF; Zhao, X; Huang, K

    2015-04-15

    A high-fidelity two-dimensional axial symmetrical multi-physics model is described in this paper as an effort to simulate the cycle performance of a recently discovered solid oxide metal-air redox battery (SOMARB). The model collectively considers mass transport, charge transfer and chemical redox cycle kinetics occurring across the components of the battery, and is validated by experimental data obtained from independent research. In particular, the redox kinetics at the energy storage unit is well represented by Johnson-Mehl-Avrami-Kolmogorov (JIVIAK) and Shrinking Core models. The results explicitly show that the reduction of Fe3O4 during the charging cycle limits the overall performance. Distributions of electrode potential, overpotential, Nernst potential, and H-2/H2O-concentration across various components of the battery are also systematically investigated. (C) 2015 Elsevier B.V. All rights reserved.

  18. Engineering correlations of variable-property effects on laminar forced convection mass transfer for dilute vapor species and small particles in air

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.; Rosner, D. E.

    1984-01-01

    A simple engineering correlation scheme is developed to predict the variable property effects on dilute species laminar forced convection mass transfer applicable to all vapor molecules or Brownian diffusing small particle, covering the surface to mainstream temperature ratio of 0.25 T sub W/T sub e 4. The accuracy of the correlation is checked against rigorous numerical forced convection laminar boundary layer calculations of flat plate and stagnation point flows of air containing trace species of Na, NaCl, NaOH, Na2SO4, K, KCl, KOH, or K2SO4 vapor species or their clusters. For the cases reported here the correlation had an average absolute error of only 1 percent (maximum 13 percent) as compared to an average absolute error of 18 percent (maximum 54 percent) one would have made by using the constant-property results.

  19. Design, Modeling, Fabrication, and Evaluation of the Air Amplifier for Improved Detection of Biomolecules by Electrospray Ionization Mass Spectrometry

    PubMed Central

    Robichaud, Guillaume; Dixon, R. Brent; Potturi, Amarnatha S.; Cassidy, Dan; Edwards, Jack R.; Sohn, Alex; Dow, Thomas A.; Muddiman, David C.

    2010-01-01

    Through a multi-disciplinary approach, the air amplifier is being evolved as a highly engineered device to improve detection limits of biomolecules when using electrospray ionization. Several key aspects have driven the modifications to the device through experimentation and simulations. We have developed a computer simulation that accurately portrays actual conditions and the results from these simulations are corroborated by the experimental data. These computer simulations can be used to predict outcomes from future designs resulting in a design process that is efficient in terms of financial cost and time. We have fabricated a new device with annular gap control over a range of 50 to 70 μm using piezoelectric actuators. This has enabled us to obtain better aerodynamic performance when compared to the previous design (2× more vacuum) and also more reproducible results. This is allowing us to study a broader experimental space than the previous design which is critical in guiding future directions. This work also presents and explains the principles behind a fractional factorial design of experiments methodology for testing a large number of experimental parameters in an orderly and efficient manner to understand and optimize the critical parameters that lead to obtain improved detection limits while minimizing the number of experiments performed. Preliminary results showed that several folds of improvements could be obtained for certain condition of operations (up to 34 folds). PMID:21499524

  20. Mass loading of size-segregated atmospheric aerosols in the ambient air during fireworks episodes in eastern Central India.

    PubMed

    Nirmalkar, Jayant; Deb, Manas K; Deshmukh, Dhananjay K; Verma, Santosh K

    2013-04-01

    The effects of combustion of the fire crackers on the air quality in eastern Central India were studied for the first time during Diwali festival. This case study analyzes the size distribution and temporal variation of aerosols collected in the rural area of eastern Central India during pre-diwali, Diwali and post-diwali period for the year of 2011. Fifteen aerosol samples were collected during the special case study of Diwali period using Andersen sampler. The mean concentrations of PM10 (respirable particulate matter) were found to be 212.8 ± 4.2, 555.5 ± 20.2 and 284.4 ± 5.8 during pre-diwali, Diwali and post-diwali period, respectively. During Diwali festival PM10 concentration was about 2.6 and 1.9 times higher than pre-diwali and post-diwali period, respectively. PM2.5 (fine) and PM1 (submicron) concentrations during Diwali festival were more than 2 times higher than pre-diwali and post-diwali.

  1. Distortion of thermospheric air masses by horizontal neutral winds over Poker Flat Alaska measured using an all-sky scanning Doppler imager

    NASA Astrophysics Data System (ADS)

    Dhadly, M. S.; Conde, M.

    2016-01-01

    An air mass transported by a wind field will become distorted over time by any gradients present in the wind field. To study this effect in Earth's thermosphere, we examine the behavior of a simple parameter that we describe here as the "distortion gradient." It incorporates all of the wind field's departures from uniformity and is thus capable of representing all contributions to the distortion or mixing of air masses. The distortion gradient is defined such that it is always positive, so averaging over time and/or space does not suppress small-scale features. Conventional gradients, by contrast, are signed quantities that would often average to zero. To analyze the climatological behavior of this distortion gradient, we used three years (2010, 2011, and 2012) of thermospheric F region wind observations from a high-latitude ground-based all-sky wavelength scanning Doppler Fabry-Perot interferometer located at Poker Flat Alaska. Climatological averaging of the distortion gradient allowed us to investigate its diurnal and seasonal (annual) behaviors at our observing location. Distortion was observed to be higher before local magnetic midnight and to be seasonally dependent. While maximum distortion occurred before local magnetic midnight under all geomagnetic conditions, the peak distortion occurred earlier under moderate geomagnetic conditions as compared to the quiet geomagnetic conditions and even earlier still when geomagnetic conditions were active. Peak distortion was stronger and appeared earlier when interplanetary magnetic field (IMF) was southward compared to northward. By contrast, we could not resolve any time-shift effect due to the IMF component tangential to Earth's orbit.

  2. Rainwater monocarboxylic and dicarboxylic acid concentrations in southeastern North Carolina, USA, as a function of air-mass back-trajectory

    NASA Astrophysics Data System (ADS)

    Brooks Avery, G.; Kieber, Robert J.; Witt, Melanie; Willey, Joan D.

    Eight organic acids were measured in 111 rain events occurring between September 1996 and May 1998 in Wilmington, North Carolina. Formic and acetic acids were the most abundant comprising approximately 75% of the total molar quantity of organic acids. The annual volume-weighted concentrations of organic acids in order of decreasing abundance in rainwater was formic (9.9 μM), acetic (7.3 μM), oxalic (1.8 μM), lactic (1.3 μM), succinic (1.0 μM), malonic (0.7 μM), pyruvic (0.3 μM), and maleic (0.1 μM), with methanesulfonic and glyoxylic acids usually below their detection limit. Growing season back-trajectory data provided strong evidence that terrestrial organic acid sources dominated over marine sources. Air mass back-trajectory analysis indicated that during the growing season air mass origin had a consistent impact on concentrations of rainwater organic acids. Rain with continental back-trajectories coming from the west had the highest concentrations of organic acids while two predominately marine back-trajectories had the lowest concentrations. Concentrations of organic acids in non-growing season rain did not display a consistent pattern indicating variability in sources. Seasonality of individual organic acids for specific back-trajectories was most pronounced in terrestrial back-trajectories and least in the marine back-trajectories indicating that seasonality in rainwater organic acid concentrations is driven by variations in terrestrial sources. Formic to acetic acid ratios (F:A), previously an indicator of terrestrial versus marine sources of these organic acids, were similar for all back-trajectories reflecting anthropogenic impacts on F:A locally and regionally. The ratios of malonic to succinic acids (M:S), also an indicator of sources for these acids, indicated direct anthropogenic sources for terrestrial back-trajectories and secondary processes for marine back-trajectories.

  3. Origin of the water vapor responsible for the European extreme rainfalls of August 2002: 1. High-resolution simulations and tracking of air masses

    NASA Astrophysics Data System (ADS)

    Gangoiti, G.; SáEz de CáMara, E.; Alonso, L.; Navazo, M.; Gómez, M. C.; Iza, J.; GarcíA, J. A.; Ilardia, J. L.; MilláN, M. M.

    2011-11-01

    This article investigates an extreme rainfall event occurred over wide areas of central Europe on August 11-13, 2002. By using a synergistic approach that includes regional modeling, air mass tracking, and observational data sets, the importance of moisture accumulation processes in the Western Mediterranean basin (WMB) is acknowledged as an important mechanism responsible for the magnitude of this event. The RAMS-HYPACT modeling system is used to track air masses from potential marine sources of evaporation. MODIS water vapor products, wind profilers and surface rain gauge measurements are used to substantiate our simulations. Results show that most of the precipitation occurring in central Europe during the initiation of the rainfall episode (August 11) came from vapor accumulated over 4 days (August 6-9) within the WMB: the vapor was transported, after the irruption of the Vb cyclone Ilse, through the Italian Peninsula and the Adriatic Sea, into the target area, causing the precipitation episode. On August 12 and 13 the marine sources of evaporation changed to include the north-Atlantic region. The north-African convergence region, the eastern Mediterranean and the Black Sea are revealed to be sources more related to the intense rainfall experienced in eastern Europe. The subsidence-related processes through which pollutants and water vapor can accumulate for several days in the WMB are shown to be very relevant for this event. The quantification of the evaporative sources, responsible for the extreme rainfall events in central Europe, and the relative importance of marine and terrestrial sources within a chosen regional domain are discussed in the companion following article.

  4. Circulating serotonin in vertebrates.

    PubMed

    Maurer-Spurej, E

    2005-08-01

    The role of circulating serotonin is unclear and whether or not serotonin is present in the blood of non-mammalian species is not known. This study provides the first evidence for the presence of serotonin in thrombocytes of birds and three reptilian species, the endothermic leatherback sea turtle, the green sea turtle and the partially endothermic American alligator. Thrombocytes from a fresh water turtle, American bullfrog, Yellowfin tuna, and Chinook salmon did not contain serotonin. Serotonin is a vasoactive substance that regulates skin blood flow, a major mechanism for endothermic body temperature regulation, which could explain why circulating serotonin is present in warm-blooded species. The temperature sensitivity of human blood platelets with concomitant changes in serotonin content further supports a link between circulating serotonin and thermoregulation. Phylogenetic comparison of the presence of circulating serotonin indicated an evolutionary divergence within reptilian species that might coincide with the emergence of endothermy. PMID:16041566

  5. Structural Determination of Circulation.

    ERIC Educational Resources Information Center

    Blankenburg, William B.

    1981-01-01

    Analyzes the effects of both structural factors (demographics, economic conditions, and competition) and discretionary factors (content, design, and marketing techniques) and concludes that it is the former that determine a newspaper's circulation. (FL)

  6. Comparison of negative-ion proton-transfer with iodide ion chemical ionization mass spectrometry for quantification of isocyanic acid in ambient air

    NASA Astrophysics Data System (ADS)

    Woodward-Massey, Robert; Taha, Youssef M.; Moussa, Samar G.; Osthoff, Hans D.

    2014-12-01

    Isocyanic acid (HNCO) is a trace gas pollutant of potential importance to human health whose measurement has recently become possible through the development of negative-ion proton-transfer chemical ionization mass spectrometry (NI-PT-CIMS) with acetate reagent ion. In this manuscript, an alternative ionization and detection scheme, in which HNCO is quantified by iodide CIMS (iCIMS) as a cluster ion at m/z 170, is described. The sensitivity was inversely proportional to water vapor concentration but could be made independent of humidity changes in the sampled air by humidifying the ion-molecule reaction (IMR) region of the CIMS. The performance of the two ionization schemes was compared and contrasted using ambient air measurements of HNCO mixing ratios in Calgary, AB, Canada, by NI-PT-CIMS with acetate reagent ion from Dec 16 to 20, 2013, and by the same CIMS operated in iCIMS mode from Feb 3 to 7, 2014. The iCIMS exhibited a greater signal-to-noise ratio than the NI-PT-CIMS, not because of its sensitivity, which was lower (˜0.083 normalized counts per second (NCPS) per parts-per-trillion by volume (pptv) compared to ˜9.7 NCPS pptv-1), but because of a much lower and more stable background (3 ± 4 compared to a range of ˜2 × 103 to ˜6 × 103 NCPS). For the Feb 2014 data set, the HNCO mixing ratios in Calgary air ranged from <12 to 94 pptv (median 34 pptv), were marginally higher at night than during day, and correlated with nitrogen oxide (NOx = NO + NO2) mixing ratios and submicron particle volume. The ratios of HNCO to NOx observed are within the range of emission ratios reported for gasoline-powered motor vehicles.

  7. Determination of fragrance allergens in indoor air by active sampling followed by ultrasound-assisted solvent extraction and gas chromatography-mass spectrometry.

    PubMed

    Lamas, J Pablo; Sanchez-Prado, Lucia; Garcia-Jares, Carmen; Llompart, Maria

    2010-03-19

    Fragrances are ubiquitous pollutants in the environment, present in the most of household products, air fresheners, insecticides and cosmetics. Commercial perfumes may contain hundreds of individual fragrance chemicals. In addition to the widespread use and exposure to fragranced products, many of the raw fragrance materials have limited available health and safety data. Because of their nature as artificial fragrances, inhalation should be considered as an important exposure pathway, especially in indoor environments. In this work, a very simple, fast, and sensitive methodology for the analysis of 24 fragrance allergens in indoor air is presented. Considered compounds include those regulated by the EU Directive, excluding limonene; methyl eugenol was also included due to its toxicity. The proposed methodology is based on the use of a very low amount of adsorbent to retain the target compounds, and the rapid ultrasound-assisted solvent extraction (UAE) using a very low volume of solvent which avoids further extract concentration. Quantification was performed by gas chromatography coupled to mass spectrometry (GC-MS). The influence of main factors involved in the UAE step (type of adsorbent and solvent, solvent volume and extraction time) was studied using an experimental design approach to account for possible factor interactions. Using the optimized procedure, 0.2 m(-3) air are sampled, analytes are retained on 25 mg Florisil, from which they are extracted by UAE (5 min) with 2 mL ethyl acetate. Linearity was demonstrated in a wide concentration range. Efficiency of the total sampling-extraction process was studied at several concentration levels (1, 5 and 125 microg m(-3)), obtaining quantitative recoveries, and good precision (RSD<10%). Method detection limits were < or =0.6 microg m(-3). Finally, the proposed method was applied to real samples collected in indoor environments in which several of the target compounds were determined.

  8. Real-time quantification of traces of biogenic volatile selenium compounds in humid air by selected ion flow tube mass spectrometry.

    PubMed

    Sovová, Kristýna; Shestivska, Violetta; Španěl, Patrik

    2012-06-01

    Biological volatilization of selenium, Se, in a contaminated area is an economical and environmentally friendly approach to phytoremediation techniques, but analytical methods for monitoring and studying volatile compounds released in the process of phytovolatilization are currently limited in their performance. Thus, a new method for real time quantification of trace amounts of the vapors of hydrogen selenide (H(2)Se), methylselenol (CH(3)SeH), dimethylselenide ((CH(3))(2)Se), and dimethyldiselenide ((CH(3))(2)Se(2)) present in ambient air adjacent to living plants has been developed. This involves the characterization of the mechanism and kinetics of the reaction of H(3)O(+), NO(+), and O(2)(+•) reagent ions with molecules of these compounds and then use of the rate constants so obtained to determine their absolute concentrations in air by selected ion flow tube mass spectrometry, SIFT-MS. The results of experiments demonstrating this method on emissions from maize (Zea mays) seedlings cultivated in Se rich medium are also presented.

  9. Atmospheric Circulation and Dynamics

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay S.; Rengel, Miriam

    The deep atmosphere of Venus ( ˜ 180 km including the thermosphere) presents both observational and modeling challenges. Its thick, nearly uniform global cloud cover makes it difficult to fathom the vertical structure of the global circulation through available techniques that are applied to Earth's atmosphere. Further, the slow rotation of the planet and the consequential prevailing cyclostrophic balance restricts easy inferences about the meridional flow and circulation (Gierasch et al. 1997, Read 1986, Schubert et al. 2007).

  10. Circulating venous bubbles in children after diving.

    PubMed

    Lemaitre, Frederic; Carturan, Daniel; Tourney-Chollet, Claire; Gardette, Bernard

    2009-02-01

    Doppler ultrasonic detection of circulating venous bubbles after a scuba dive is a useful index of decompression safety in adults, since a relationship between bubbles and the risk of decompression sickness has been documented. No study, however, has investigated circulating venous bubbles in young recreational divers after their usual dives. The aim of this study was to determine whether these bubbles would be detected in children who performed a single dive without any modification in their diving habits. Ten young recreational divers (13.1 +/- 2.3 years) performed their usual air dive. They were Doppler-monitored 20 min before the dive (12 +/- 3 m for 26 +/- 7 min) and for 60 min after surfacing, at 20-min intervals. No circulating venous bubbles were detected after the children surfaced. The results showed that during a usual shallow diving session, venous bubbles were not detected in children.

  11. A Longitudinal Cohort Study of Body Mass Index and Childhood Exposure to Secondhand Tobacco Smoke and Air Pollution: The Southern California Children’s Health Study

    PubMed Central

    Shen, Ernest; Gilliland, Frank D.; Jerrett, Michael; Wolch, Jennifer; Chang, Chih-Chieh; Lurmann, Frederick; Berhane, Kiros

    2014-01-01

    Background: Childhood body mass index (BMI) and obesity prevalence have been associated with exposure to secondhand smoke (SHS), maternal smoking during pregnancy, and vehicular air pollution. There has been little previous study of joint BMI effects of air pollution and tobacco smoke exposure. Methods: Information on exposure to SHS and maternal smoking during pregnancy was collected on 3,318 participants at enrollment into the Southern California Children’s Health Study. At study entry at average age of 10 years, residential near-roadway pollution exposure (NRP) was estimated based on a line source dispersion model accounting for traffic volume, proximity, and meteorology. Lifetime exposure to tobacco smoke was assessed by parent questionnaire. Associations with subsequent BMI growth trajectory based on annual measurements and attained BMI at 18 years of age were assessed using a multilevel modeling strategy. Results: Maternal smoking during pregnancy was associated with estimated BMI growth over 8-year follow-up (0.72 kg/m2 higher; 95% CI: 0.14, 1.31) and attained BMI (1.14 kg/m2 higher; 95% CI: 0.66, 1.62). SHS exposure before enrollment was positively associated with BMI growth (0.81 kg/m2 higher; 95% CI: 0.36, 1.27) and attained BMI (1.23 kg/m2 higher; 95% CI: 0.86, 1.61). Growth and attained BMI increased with more smokers in the home. Compared with children without a history of SHS and NRP below the median, attained BMI was 0.80 kg/m2 higher (95% CI: 0.27, 1.32) with exposure to high NRP without SHS; 0.85 kg/m2 higher (95% CI: 0.43, 1.28) with low NRP and a history of SHS; and 2.15 kg/m2 higher (95% CI: 1.52, 2.77) with high NRP and a history of SHS (interaction p-value 0.007). These results suggest a synergistic effect. Conclusions: Our findings strengthen emerging evidence that exposure to tobacco smoke and NRP contribute to development of childhood obesity and suggest that combined exposures may have synergistic effects. Citation: McConnell R, Shen E

  12. Assessing Patterns in the Surface Electric Field Prior to First CG Flashes and After Last CG Flashes in Air-Mass Thunderstorms

    NASA Astrophysics Data System (ADS)

    Williams, D. E.; Beasley, W. H.; Hyland, P. T.

    2007-12-01

    In an effort to elicit patterns in the temporal and spatial evolution of the contours of surface electric field relevant to the occurrence of cloud-to-ground (CG) lightning, we have analyzed data from the network of 31 electric-field mills jointly operated by the John F. Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). To identify cases of interest, we used lightning ground-strike data, maps of in-cloud lightning discharges, rainfall data, and radar data. In particular, we have focused on two critical problems: 1) estimation of when and where the first CG flash in a storm might occur and 2) assessment of the likelihood of CG flashes occurring late in a storm after a long period without a CG flash. Our long-term goal is to understand the evolution of surface contours of electric field for periods of 30 minutes or more before the first flash of any kind and 30 minutes or more before and after the last flash of any kind. For practical reasons, we are reporting here on analysis of data for periods of 30 minutes before the first CG flash and 30 minutes after the last CG flash in each storm of interest. We have analyzed electric-field data from isolated air-mass convective storms that developed over KSC/CCAFS from late May through early September, 2004-2006. To identify thunderstorms that fit the air-mass, or "pop-up" criteria, we started by examining rainfall and CG lightning data, then looked at radar data. Then, for the storms selected, we performed a two-pass Barnes objective analysis on the electric-field data. Each analysis cycle resulted in one contour plot of 20-second averaged data, yielding 90 plots for each 30 minute interval, which we then animated. This resulted in 58 animations of the field contours prior to first CG flashes and 62 animations of the field contours after last CG flashes. Preliminary impressions from examinations of these cases suggest that the electric-field contours before the first flash exhibit a smooth transition

  13. Determining the levels of volatile organic pollutants in urban air using a gas chromatography-mass spectrometry method.

    PubMed

    Nicoara, Simona; Tonidandel, Loris; Traldi, Pietro; Watson, Jonathan; Morgan, Geraint; Popa, Ovidiu

    2009-01-01

    The paper presents the application of a method based on coupled gas chromatography-mass spectrometry, using an isotopically labelled internal standard for the quantitative analysis of benzene (B), toluene (T), ethyl benzene (E), and o-, m-, p-xylenes (X). Their atmospheric concentrations were determined based on short-term sampling, in different sites of Cluj-Napoca, a highly populated urban centre in N-W Romania, with numerous and diversified road vehicles with internal combustion engines. The method is relatively inexpensive and simple and shows good precision and linearity in the ranges of 7-60 mug/m(3) (B), 13-90 mug/m(3) (T), 7-50 mug/m(3) (E), 10-70 mug/m(3) (X-m,p), and 20-130 mug/m(3) (X-o). The limits of quantitation/detection of the method LOQ/LOD are of 10/5 mug/m(3) (Xo), 5/3 mug/m(3) (B, E, X-m,p), and of 3/1 mug/m(3) (T), respectively. PMID:20168976

  14. Fraction and composition of NOy transported in air masses lofted from the North American continental boundary layer

    NASA Astrophysics Data System (ADS)

    Parrish, D. D.; Ryerson, T. B.; Holloway, J. S.; Neuman, J. A.; Roberts, J. M.; Williams, J.; Stroud, C. A.; Frost, G. J.; Trainer, M.; Hübler, G.; Fehsenfeld, F. C.; Flocke, F.; Weinheimer, A. J.

    2004-05-01

    Five field studies have included research aircraft flights over the continental United States and the western North Atlantic Ocean from 1996 through 2000 in spring, summer, and fall seasons. The major source of NOx in this region is fossil fuel combustion, which is localized within the continental boundary layer (CBL). We use CO as a tracer of these anthropogenic emissions to estimate the fraction of the emitted NOx that is exported to the free troposphere (FT), either as NOx itself or as its oxidation products. This export was identified as plumes enhanced in CO above an estimated background by at least 30 ppbv, which account for 20-31% of the air parcels sampled in the FT during the five field studies. These plumes were encountered throughout the FT up to the 8 km ceiling of the aircraft but were primarily located just above the CBL with average altitudes of 3.0-4.1 km above ground level. In the summer over the continent, only 20 ± 5% of the originally emitted nitrogen oxides was transported in those plumes. This fraction is in reasonable accord with model results, but the models include only deep convection and not the shallow CBL venting mechanisms responsible for the observed plumes. During the two field studies in the early fall and in the spring over the western North Atlantic, we find that 9 ± 4% of the NOy was transported, although [2004] suggest that this is an underestimate and that 15 ± 11% is more accurate. Both of these numbers indicate that model results in the literature overestimate the amount of NOy transported from the CBL to the FT. In these five field studies, HNO3 generally accounted for one-half to two-thirds of the NOy, which is in contrast to the dominance by NOx and organic nitrates suggested by models. Over the North Atlantic, this difference is likely due to further photochemical processing of the NOy species within the FT and over the continent due to the different transport mechanism considered in the models.

  15. Impact of northern and southern air mass transport on the temporal distribution of atmospheric (210)Po and (210)Pb in the east coast of Johor, Malaysia.

    PubMed

    Sabuti, Asnor Azrin; Mohamed, Che Abd Rahim

    2016-09-01

    Concentration activities of (210)Pb and (210)Po in the PM10 were determined to discuss their distribution and chemical behavior in relation to meteorological parameters especially in air mass transport during monsoon events. Marine aerosol samples were collected between January 2009 and December 2010 at the coastal region of Mersing, which is located in the southern South China Sea and is about 160 km northeast of Johor Bahru, as part of the atmosphere-ocean interaction program in Malaysia. About 47 PM10 samples were collected using the Sierra-Andersen model 1200 PM10 sampler over a 2-year sampling campaign between January 2009 and December 2010. Samples were processed using acid digestion sequential extraction techniques to analyze various fractions such as Fe and Mn oxides, organic matter, and residual fractions. While, (210)Pb and (210)Po activities were measured with the Gross Alpha/Beta Counting System model XLB-5 Tennelec® Series 5 and the Alpha Spectrometry (model Alpha Analyst Spectroscopy system with a silicon-surface barrier detector), respectively. The distribution activities of (210)Pb and (210)Po in the PM10 samples were varied from 162 to 881 μBq/m(3) with mean value of 347 ± 170 μBq/m(3) and from 85 to 1009 μBq/m(3) with mean value of 318 ± 202 μBq/m(3), respectively. The analysis showed that (210)Po activity in our samples lies in a border and higher range than global distribution values due to contributions from external sources injected to the atmosphere. The speciation of (210)Pb and (210)Po in marine aerosol corresponds to transboundary haze; e.g., biomass burning especially forest fires and long-range air mass transport of terrestrial dust has enriched concentrations of particle mass in the local atmosphere. The monsoon seems to play an important role in transporting terrestrial dust from Indo-China and northern Asia especially during the northeast monsoon, as well as biogenic pollutants originating from Sumatra and the southern

  16. Impact of northern and southern air mass transport on the temporal distribution of atmospheric (210)Po and (210)Pb in the east coast of Johor, Malaysia.

    PubMed

    Sabuti, Asnor Azrin; Mohamed, Che Abd Rahim

    2016-09-01

    Concentration activities of (210)Pb and (210)Po in the PM10 were determined to discuss their distribution and chemical behavior in relation to meteorological parameters especially in air mass transport during monsoon events. Marine aerosol samples were collected between January 2009 and December 2010 at the coastal region of Mersing, which is located in the southern South China Sea and is about 160 km northeast of Johor Bahru, as part of the atmosphere-ocean interaction program in Malaysia. About 47 PM10 samples were collected using the Sierra-Andersen model 1200 PM10 sampler over a 2-year sampling campaign between January 2009 and December 2010. Samples were processed using acid digestion sequential extraction techniques to analyze various fractions such as Fe and Mn oxides, organic matter, and residual fractions. While, (210)Pb and (210)Po activities were measured with the Gross Alpha/Beta Counting System model XLB-5 Tennelec® Series 5 and the Alpha Spectrometry (model Alpha Analyst Spectroscopy system with a silicon-surface barrier detector), respectively. The distribution activities of (210)Pb and (210)Po in the PM10 samples were varied from 162 to 881 μBq/m(3) with mean value of 347 ± 170 μBq/m(3) and from 85 to 1009 μBq/m(3) with mean value of 318 ± 202 μBq/m(3), respectively. The analysis showed that (210)Po activity in our samples lies in a border and higher range than global distribution values due to contributions from external sources injected to the atmosphere. The speciation of (210)Pb and (210)Po in marine aerosol corresponds to transboundary haze; e.g., biomass burning especially forest fires and long-range air mass transport of terrestrial dust has enriched concentrations of particle mass in the local atmosphere. The monsoon seems to play an important role in transporting terrestrial dust from Indo-China and northern Asia especially during the northeast monsoon, as well as biogenic pollutants originating from Sumatra and the southern

  17. An evaluation of the impact of urban air pollution on paint dosimeters by tracking changes in the lipid MALDI-TOF mass spectra profile.

    PubMed

    Herrera, A; Navas, N; Cardell, C

    2016-08-01

    We evaluated the impact of urban air pollution on egg yolk tempera paint dosimeters (binary mixture samples made with historic artist´s blue, red and white pigments) by tracking changes over time in their lipid matrix-assisted laser desorption ionization time-of-flight mass spectra (MALDI-TOF-MS) profiles. We studied triacylglycerols (TGs), phospholipids (PLs) and their oxidation by-products from paint dosimeters that had been exposed outdoors for six months to the polluted atmosphere in the city center of Granada (Spain). Four types of chickens' eggs were also analyzed to find out whether their lipid mass spectra (lipid fingerprints) varied significantly. The ultimate goal of this research is to provide a precise analytical protocol to show whether the changes in the egg yolk identified in paint dosimeters are due to pigment-binder interactions. The Bligh-Dyer (BD) method was optimized for the extraction of the lipids. This innovative procedure included a washing-step prior to the mass spectrometric analysis, which proved crucial for obtaining higher quality lipid fingerprints. A novel interpretation of the results is proposed by applying the BD method, which suggests that transesterification processes occurred in the lipid fractions that were catalyzed by the pigments in the paint dosimeters. In blank dosimeters specific ions produced by oxidative cleavage of PLs and/or TGs may be used as markers of the presence of egg yolk binders. The composition and structure of the specific lipid compounds are also tentatively proposed. In aged dosimeters the intact content of the TGs and PLs decreased; however, we propose that short-chain oxidative products arising from TGs and PLs are present in all the samples, except for the white lead based dosimeter. We end with a new explanation as to why this dosimeter behaves differently from the others.

  18. An evaluation of the impact of urban air pollution on paint dosimeters by tracking changes in the lipid MALDI-TOF mass spectra profile.

    PubMed

    Herrera, A; Navas, N; Cardell, C

    2016-08-01

    We evaluated the impact of urban air pollution on egg yolk tempera paint dosimeters (binary mixture samples made with historic artist´s blue, red and white pigments) by tracking changes over time in their lipid matrix-assisted laser desorption ionization time-of-flight mass spectra (MALDI-TOF-MS) profiles. We studied triacylglycerols (TGs), phospholipids (PLs) and their oxidation by-products from paint dosimeters that had been exposed outdoors for six months to the polluted atmosphere in the city center of Granada (Spain). Four types of chickens' eggs were also analyzed to find out whether their lipid mass spectra (lipid fingerprints) varied significantly. The ultimate goal of this research is to provide a precise analytical protocol to show whether the changes in the egg yolk identified in paint dosimeters are due to pigment-binder interactions. The Bligh-Dyer (BD) method was optimized for the extraction of the lipids. This innovative procedure included a washing-step prior to the mass spectrometric analysis, which proved crucial for obtaining higher quality lipid fingerprints. A novel interpretation of the results is proposed by applying the BD method, which suggests that transesterification processes occurred in the lipid fractions that were catalyzed by the pigments in the paint dosimeters. In blank dosimeters specific ions produced by oxidative cleavage of PLs and/or TGs may be used as markers of the presence of egg yolk binders. The composition and structure of the specific lipid compounds are also tentatively proposed. In aged dosimeters the intact content of the TGs and PLs decreased; however, we propose that short-chain oxidative products arising from TGs and PLs are present in all the samples, except for the white lead based dosimeter. We end with a new explanation as to why this dosimeter behaves differently from the others. PMID:27216656

  19. Rotor blade construction for circulation control aircraft

    NASA Technical Reports Server (NTRS)

    Carter, Sr., Donald R. (Inventor); Krauss, Timothy A. (Inventor); Sedlak, Matthew (Inventor)

    1986-01-01

    A circulation control aircraft rotor blade having a spanwise Coanda surface 16 and a plurality of spanwise extending flexible composite material panels 18 cooperating with the surface to define slots for the discharge of compressed air from within the blade with each panel having first flexure means 60 associated with screw adjustments 36 for establishing a slot opening preload and second flexure means 62 associated with screw adjustments 38 for establishing a slot maximum opening.

  20. Modeling biomass gasification in circulating fluidized beds

    NASA Astrophysics Data System (ADS)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous

  1. Structure and Composition of Air-Plane Soots and Surrogates Analyzed by Raman Spectroscopy and Laser/Ions Desorption Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ortega, Ismael; Chazallon, Bertrand; Carpentier, Yvain; Irimiea, Cornelia; Focsa, Cristian; Ouf, François-Xavier; Salm, François; Delhaye, David; Gaffié, Daniel; Yon, Jérôme

    2015-04-01

    Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion [1]. An aircraft exhaust plume contains species emitted by the engines, species formed in the plume from the emitted species and atmospheric species that become entrained into the plume. The majority of emitted species (gases and soot particles) are produced by the combustion of kerosene with ambient air in the combustion chamber of the engine. Emissions of soot particles by air-planes produce persistent contrails in the upper troposphere in ice-supersaturated air masses that contribute to cloudiness and impact the radiative properties of the atmosphere. These aerosol-cloud interactions represent one of the largest sources of uncertainty in global climate models [2]. Though the formation of atmospheric ice particles has been studied since many years [3], there are still numerous opened questions on nucleation properties of soot particles [4], as the ice nucleation experiments showed a large spread in results depending on the nucleation mode chosen and origin of the soot produced. Most likely one of the reasons behind these discrepancies resides in the different physico-chemical properties (composition, structure) of soot particles produced in different conditions, e.g. with respect to fuel or combustion techniques. In this work, we use Raman microscopy (266, 514 and 785 nm excitation) and ablation techniques (SIMS, Secondary Ions Mass Spectrometry, and Laser Desorption Mass Spectrometry) to characterize soot particles produced from air-plane at different engine regimes simulating a landing and taking-off (LTO) cycle. First, the spectral parameters of the first-order Raman band of various soot samples, collected from three different sources in the frame of the MERMOSE project (http://mermose.onera.fr/): PowerJet SaM-146 turbofan (four engine regimes), CAST generator (propane fuel, four different global equivalence ratios), and Kerosene laboratory flame

  2. Connection between ozone concentration and atmosphere circulation at peak Moussala

    NASA Astrophysics Data System (ADS)

    Nojarov, Peter; Ivanov, Peter; Kalapov, Ivo; Penev, Ilia; Drenska, Mirolujba

    2009-09-01

    Connection between ozone concentration and atmosphere circulation is investigated based on measurements at BEO station, peak Moussala (2,925 m a.s.l.), for the period 09 August 2006 to 29 January 2008. Ozone concentration data are collected with UV-analyzer “Environnement O3 42” and meteo data with weather station “Vaisala”. There are measurements of 7Be. Data from NOAA HYSPLIT model for particle trajectories are also used. Eight wind directions and three ranges of wind velocities are employed in the analysis. A comparison of ozone concentrations in upward and downward air transport according to HYSPLIT model is made. The number of cases with ozone concentration above 63 ppb has been counted. Mann-Whitney nonparametric test is employed as a basic statistical method. Correlation between atmosphere pressure and tropospheric ozone content is made. The same is done for 7Be and ozone. The main conclusion is that there is not any local or regional pollution effect detectable at peak Moussala, but most of the ozone measured is due to emissions of hydrocarbons and NO x over a larger region. There could be some regional sources of ozone building substances in southwest direction from peak Moussala. Air transported from the north quarter has higher ozone concentrations compared to the south quarter. In vertical direction, upward transport of air masses shows higher values of ozone concentration. Higher wind velocity is associated with low ozone concentrations at peak Moussala. The annual course of ozone concentration has summer maximum and winter minimum. There is right connection between air pressure and ozone concentration. The same is valid for the correlation between 7Be and ozone. Diurnal ozone course shows daytime maximum in winter and nighttime maximum in summer.

  3. On the North Atlantic circulation

    SciTech Connect

    Schmitz, W.J. Jr.; McCartney, M.S. )

    1993-02-01

    A summary for North Atlantic circulation is proposed to replace the circulation scheme hypothesized by Worthington in 1976. Divergences from the previous model are in thermohaline circulation, cross-equatorical transport and Florida Current sources, flow in the eastern Atlantic, circulation in the Newfoundland Basin, slope water currents, and flow pattern near the Bahamas. The circulation patterns presented here are consistent with the majority of of published accounts of flow components. 77 refs., 14 figs., 3 tabs.

  4. Concentrations of Semivolatile Organic Compounds Associated with African Dust Air Masses in Mali, Cape Verde, Trinidad and Tobago, and the U.S. Virgin Islands, 2001-2008

    USGS Publications Warehouse

    Garrison, Virginia H.; Foreman, William T.; Genualdi, Susan A.; Majewski, Michael S.; Mohammed, Azad; Simonich, Staci Massey

    2011-01-01

    Every year, billions of tons of fine particles are eroded from the surface of the Sahara Desert and the Sahel of West Africa, lifted into the atmosphere by convective storms, and transported thousands of kilometers downwind. Most of the dust is carried west to the Americas and the Caribbean in the Saharan Air Layer (SAL). Dust air masses predominately impact northern South America during the Northern Hemisphere winter and the Caribbean and Southeastern United States in summer. Dust concentrations vary considerably temporally and spatially. In a dust source region (Mali), concentrations range from background levels of 575 micrograms per cubic meter (mu/u g per m3) to 13,000 mu/u g per m3 when visibility degrades to a few meters (Gillies and others, 1996). In the Caribbean, concentrations of 200 to 600 mu/u g per m3 in the mid-Atlantic and Barbados (Prospero and others, 1981; Talbot and others, 1986), 3 to 20 mu/u g per m3 in the Caribbean (Prospero and Nees, 1986; Perry and others, 1997); and >100 mu/u g per m3 in the Virgin Islands (this dataset) have been reported during African dust conditions. Mean dust particle size decreases as the SAL traverses from West Africa to the Caribbean and Americas as a result of gravitational settling. Mean particle size reaching the Caribbean is <1 micrometer (mu/u m) (Perry and others, 1997), and even finer particles are carried into Central America, the Southeastern United States, and maritime Canada. Particles less than 2.5 mu/u m diameter (termed PM2.5) can be inhaled deeply into human lungs. A large body of literature has shown that increased PM2.5 concentrations are linked to increased cardiovascular/respiratory morbidity and mortality (for example, Dockery and others, 1993; Penn and others, 2005).

  5. Determination of a wide range of volatile organic compounds in ambient air using multisorbent adsorption/thermal desorption and gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Pankow, J.F.; Luo, W.; Isabelle, L.M.; Bender, D.A.; Baker, R.J.

    1998-01-01

    Adsorption/thermal desorption with multisorbent air-sampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3- trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02-0.06 ppbv. No breakthrough was detected with the prescribed sample volumes. Analyte stability on the cartridges was very good. Excellent recoveries were obtained with independent check standards. Travel spike recoveries ranged from 90 to 110% for 72 of the 87 compounds. The recoveries were less than 70% for bromomethane and chloroethene and for a few compounds such as methyl acetate that are subject to losses by hydrolysis; the lowest travel spike recovery was obtained for bromomethane (62%). Blank values for all compounds were either below detection or very low. Ambient atmospheric sampling was conducted in New Jersey from April to December, 1997. Three sites characterized by low, moderate, and high densities of urbanization/traffic were sampled. The median detected concentrations of the compounds were either similar at all three sites (as with the chlorofluorocarbon compounds) or increased with the density of urbanization/traffic (as with dichloromethane, MTBE, benzene, and toluene). For toluene, the median detected

  6. Response of air stagnation frequency to anthropogenically enhanced radiative forcing.

    PubMed

    Horton, Daniel E; Harshvardhan; Diffenbaugh, Noah S

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) Air Stagnation Index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21(st) century climate change (SRES A1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase 12-to-25% relative to late-20(th) century stagnation frequencies (3-18+ days/year). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21(st) century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. PMID:23284587

  7. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    PubMed Central

    Horton, Daniel E.; Harshvardhan; Diffenbaugh, Noah S.

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) Air Stagnation Index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRES A1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase 12-to-25% relative to late-20th century stagnation frequencies (3-18+ days/year). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. PMID:23284587

  8. Arctic circulation regimes.

    PubMed

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. PMID:26347536

  9. Arctic circulation regimes

    PubMed Central

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L.

    2015-01-01

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. PMID:26347536

  10. Circulation and Finding System.

    ERIC Educational Resources Information Center

    Pierce, A. R.

    This report describes an online minicomputer-based system, one combining library inventory control with catalog access, that was implemented at Virginia Tech's main library in order to meet the demands of increased circulation activity and rising staff costs. Following overviews of the institutional environment, the systems development department,…

  11. Circulation Aide Training Manual.

    ERIC Educational Resources Information Center

    Bergeson, Alan O.

    This training manual provides instruction on shelving and other duties for student assistants in the learning resources center at the College of Dupage, located in Illinois. It is noted that prospective student circulation aides are required to read the manual and pass a written test on policies and procedures before they are allowed to shelve…

  12. The global distribution of natural tritium in precipitation simulated with an Atmospheric General Circulation Model and comparison with observations

    NASA Astrophysics Data System (ADS)

    Cauquoin, A.; Jean-Baptiste, P.; Risi, C.; Fourré, É.; Stenni, B.; Landais, A.

    2015-10-01

    The description of the hydrological cycle in Atmospheric General Circulation Models (GCMs) can be validated using water isotopes as tracers. Many GCMs now simulate the movement of the stable isotopes of water, but here we present the first GCM simulations modelling the content of natural tritium in water. These simulations were obtained using a version of the LMDZ General Circulation Model enhanced by water isotopes diagnostics, LMDZ-iso. To avoid tritium generated by nuclear bomb testing, the simulations have been evaluated against a compilation of published tritium datasets dating from before 1950, or measured recently. LMDZ-iso correctly captures the observed tritium enrichment in precipitation as oceanic air moves inland (the so-called continental effect) and the observed north-south variations due to the latitudinal dependency of the cosmogenic tritium production rate. The seasonal variability, linked to the stratospheric intrusions of air masses with higher tritium content into the troposphere, is correctly reproduced for Antarctica with a maximum in winter. LMDZ-iso reproduces the spring maximum of tritium over Europe, but underestimates it and produces a peak in winter that is not apparent in the data. This implementation of tritium in a GCM promises to provide a better constraint on: (1) the intrusions and transport of air masses from the stratosphere, and (2) the dynamics of the modelled water cycle. The method complements the existing approach of using stable water isotopes.

  13. A paleoceanographic circulation and chemistry model

    SciTech Connect

    Southam, J.R. )

    1990-01-09

    We have developed a 3-D circulation and tracer field model for paleoceanographic applications. The development of the model was motivated by the desire to explore Cretaceous Oceanic Anoxic Events and ocean chemistry during glacial and interglacial modes of circulation. The bulk of paleoceanographic data is the consequences of biological processes operating in ancient oceans. This type of data represents the response to environmental conditions and can be used to reconstruct water mass properties. To infer both wind driven and thermohaline components of circulation in ancient oceans requires a model which relates circulation and water mass properties. With this motivation in mind we have formulated a model which satisfies the following criteria: (1) geostrophically balanced interior, (2) multiple sites for deep water production, (3) deep water production described by entraining plumes, (4) high vertical resolution in both velocity and property fields, (5) meridional varibility in wind stress and evaporation-precipitation rate, (6) applicable to basin scale where exchange with adjacent oceans described by flux conditions, and (7) the chemistry is coupled through the flux of particulate carbon sinking through the interior.

  14. Variability in deep ocean circulation from GRACE

    NASA Astrophysics Data System (ADS)

    Boening, C.; Watkins, M. M.

    2015-12-01

    Although nearly impossible to observe on a global scale, total water mass transport and inter-basin exchange are central to understanding long-term changes in ocean circulation. Of particular interest are changes in the Meridional Overturning Circulation (MOC) as they pose potential impacts in continental climtae. However, in-situ observations are limited in space and time preventing a holistic view of current variability. The representation of long-term transports in ocean models is highly dependent on the atmospheric forcing fields, which may misrepresent real interannual variability. The bottom pressure observations from the Gravity Recovery And Climate Experiment (GRACE) provide for the first time the ability to observe this global water mass transport. Here, we present the first near-global maps of variability in the depth-independent ocean circulation derived from advanced analysis of GRACE data. We find that significant variability on annual to decadal time scales exists in the deep large-scale circulation, some of which are related to the Southern Annular Mode forcing dominating Southern Ocean variability.

  15. Low-pressure gas chromatography-ion trap mass spectrometry for the fast determination of polycyclic aromatic hydrocarbons in air samples.

    PubMed

    Ravindra, Khaiwal; Godoi, Ana F L; Bencs, László; Van Grieken, René

    2006-05-12

    A low-pressure gas chromatography-ion trap mass spectrometry (LPGC-ITMS) method was investigated to shorten the analysis time for 18 US Environmental Protection Agency priority listed polycyclic aromatic hydrocarbons (PAHs). Their elution was optimised with a short, wide-bore column coupled to a deactivated capillary at the inlet end and with a long, conventional column to compare their analytical performance. The analytical figures of merit under optimal LPGC-ITMS conditions were determined with respect to chromatographic separation, S/N ratio, limit of detection and precision. The peak width at half height of 1.5s matched the ITMS duty cycle. Up to 16 PAHs in the molecular weight (MW) range of 128-278 Da could be separated in a very short time, i.e. less than 13 min using LPGC-ITMS, whereas with conventional GC-MS, it took approximately 40 min. However, LPGC-ITMS has a limited loss of separation power compared to that of conventional GC-MS due to the occurrence of three critical pairs for high-MW PAHs. For a practical evaluation, the LPGC-ITMS approach was applied to the determination of PAHs in gas and aerosol phase samples collected in the ambient air of Hasselt, Belgium.

  16. Breathing Easy over Air Quality.

    ERIC Educational Resources Information Center

    Greim, Clifton; Turner, William

    1991-01-01

    School systems should test the air in every school building for the presence and level of contaminants such as radon and asbestos and whether the ventilation system is circulating the proper amount of air. Periodic maintenance is required for all mechanical systems. (MLF)

  17. Changes in atmospheric circulation and ocean ice cover over the North Atlantic during the last 41,000 years

    SciTech Connect

    Mayewski, P.A.; Meeker, L.D.; Whitlow, S.; Twickler, M.S.; Morrison, M.C. ); Bloomfield, P. ); Alley, R.B. ); Gow, A.J.; Meese, D.A. ); Grootes, P.M. )

    1994-03-25

    High-resolution, continuous multivariate chemical records from a central Greenland ice core provide a sensitive measure of climate change and chemical composition of the atmosphere over the last 41,000 years. These chemical series reveal a record of change in the relative size and intensity of the circulation system that transported air masses to Greenland [defined here as the polar circulation index (PC)] and in the extent of ocean ice cover. Massive iceberg discharge events previously defined from the marine record are correlated with notable expansion of ocean ice cover and increases in PCI. During stadials without discharge events, ocean ice cover appears to reach some common maximum level. The massive aerosol loadings and dramatic variations in ocean ice cover documented in ice cores should be included in climate modeling.

  18. How do changes in the stratospheric circulation impact ozone?

    NASA Astrophysics Data System (ADS)

    Garny, Hella; Dameris, Martin; Bodeker, Greg; Grewe, Volker; Stenke, Andrea

    2010-05-01

    destruction) and transport are used. A diagnostic that tags ozone according to its region of production provides a measure of the relative importance of ozone from different origins. Also, together with net production rates, it can be used to assess the month-to-month transport of ozone between the defined regions. The climatology and changes in transport of ozone are compared to transport of air masses obtained from a Lagrangian diagnostic. This allows differentiation between changes in transport of ozone due to higher concentrations in the source region or due to a change in the strength of transport of air. The results show an increase in transport of air masses from the troposphere into the lower stratosphere in the tropics and increases of transport of stratospheric air into the troposphere in mid-latitudes. This is reflected in ozone with, for example, higher contributions of stratospheric ozone in the mid-latitude troposphere.

  19. Circulation pattern classification for climate change studies

    NASA Astrophysics Data System (ADS)

    Stehlik, J.; Bardossy, A.

    2003-04-01

    Several circulation pattern classifications developed for different European regions were compared regarding their mutual dependence. Circulation pattern (CP) classifications, both subjective and objective, for the British Isles, Germany and Greece were taken into account. Statistical tests were applied in order to investigate the relationships between each pair of CP classifications. It was found that each pair of classifications can not be considered to be independent. Time dependence of the relationship between CP classifications shows anomaleous behavior only when one of the classifications is subjective. This can be due to a gradual change in the methodology. Thus, one should use these classifications for climate evolution studies with care. Results showing the inter-dependence of different CP classifications were motivation for developing one classification which would be valid in every European region. For this purpose an objective and automated classification was applied. By means of daily 700 hPa data, 13 CPs were defined which explain the variability of local precipitation in 27 stations spread over the whole of Europe. The validation of this classification proved that there is almost no information lost when comparing this classification with local classifications. Based on this classification method the air pressure outputs from Global Circulation Models will be classified. Subsequently the classified circulation patterns will be used for climate change studies. For this purpose statistical downscaling of precipitation will be applied.

  20. Circulating Tumor Cells.

    PubMed

    Paoletti, Costanza; Hayes, Daniel F

    2016-01-01

    Circulating Tumor Cells (CTC) are shed from primary or secondary tumors. Prior studies have demonstrated that enumeration of CTC is a robust independent prognostic factor of progression free and overall survival in patients with early and metastatic breast cancer. CTC, as well as other circulating tumor markers, have the appealing advantages over tissue biopsy of (1) ease of collection, (2) serial evaluation, and (3) interrogation of the entire tumor burden instead of just a limited part of the tumor. Advances have been recently made in phenotyping and genotyping of CTC, which should provide insights into the predictive role of CTC for sensitivity or resistance to therapies. In addition, CTC phenotypic marker changes during the course of treatment may serve as pharmacodynamic monitoring tools. Therefore, CTC may be considered "liquid biopsies," providing prognostic and predictive clinical information as well as additional understanding of tumor heterogeneity.

  1. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  2. Anomalous North Pacific atmospheric circulation and large winter floods in the Southwestern United States

    SciTech Connect

    Ely, L.L. ); Enzel, Y. ); Cayan, D.R. )

    1994-06-01

    Specific anomalous atmospheric circulation conditions over the North Pacific are conducive to the occurrence of the largest winter floods ([ge] 10-yr return period) on rivers in six hydroclimatic subregions of Arizona and southern Utah, Nevada, and California. Composite maps of anomalies in daily 700-mb heights indicate that floods in all of the subregions are associated with a low pressure anomaly off the California coast and a high-pressure anomaly in the vicinity of either Alaska or the Aleutian Islands. Of these two major circulation features, the presence of the low is the controlling factor in determining whether large floods will occur. Shifts in the locations of the low and high pressure anomalies over the North Pacific appear to control which subregions experience floods, with high-elevation topographic features and proximity to air masses forming a major influence over the specific atmospheric circulation conditions that generate large floods in each hydroclimatic region. Concerning the interannual variability of flooding in the Southwest, there is an increased frequency of large winter floods during multiple-year periods dominated by negative SOI and a virtual absence of large floods during the intervening periods. This suggests that global-scale climatic anomalies exert a strong influence on the occurrence of severe regional winter floods. 42 refs., 7 figs., 2 tabs.

  3. Migration and circulation in Ecuador.

    PubMed

    Brea, J A

    1991-01-01

    "This study investigates labor mobility in Ecuador as a function of the socioeconomic structure of places and personal attributes of migrants and circulators (short-term movers).... Particular attention is given to the role of agrarian change in altering established migration and circulation patterns." The author finds that "circulation may significantly alter family organization and the role of women in many Ecuadorian communities."

  4. Library Circulation Systems: An Overview

    ERIC Educational Resources Information Center

    Surace, Cecily J.

    1972-01-01

    The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list. The model extends beyond the operational limits of most existing circulation systems and can be considered a reflection of the current state of the art. (36 references) (Author/NH)

  5. Physical and Radiative Properties of Aerosol Particles across the Caribbean Basin: A Comparison between Clean and Perturbed African Dust and Volcanic Ash Air Masses

    NASA Astrophysics Data System (ADS)

    Rivera, H.; Ogren, J. A.; Sheridan, P. J.; Mayol-Bracero, O.

    2009-12-01

    Aerosol’s optical and physical properties were measured during year 2007 at Cape San Juan, a ground-based station located at the northeastern tip of Puerto Rico. The three cases investigated were classified according to the origin of the air masses: clean (C), African dust (AD), and volcanic ash (VA). The instrumentation used included a sunphotometer to determine volume size distributions and aerosol optical thickness (AOT), a 3-wavelength nephelometer to determine the scattering coefficient (σsp), and a 3-wavelength particle/soot absorption photometer (PSAP) to measure the absorption coefficient (σap). The average volume size distributions were trimodal for the C (peaks at 0.14, 0.99 and 4.25 µm radius) and AD (peaks at 0.11, 1.30 and 2.00 µm radius) cases and bimodal for the VA (peaks at 0.19 and 2.75 µm radius) case. Fine and coarse modes maxima for AD occurred at radii smaller than for VA, confirming the different origins of those particles. The average values for the total σsp were higher for AD (82.9 Mm-1) and VA (33.7 Mm-1) compared to C (16.6 Mm-1). The same happened for the AOT maximum values at 500 nm with 0.92, 0.30, and 0.06 for AD, VA, and C, respectively. The observed increase in the values of the Angstrom exponent (å) is indicative of a decrease in the size of the particles associated to VA (å= 0.27) and AD (å =0.89) when compared to C (å =0.24). The volume size distributions and thus the mass were dominated by the coarse mode (> 1.0 µm) especially for the AD case. Results have shown that AD as well as VA has a significant impact on the physical and radiative properties across Puerto Rico and the Caribbean. Additional results on the AOT wavelength dependence and on the annual variability of the properties under study will be presented.

  6. Circulation Control in NASA's Vehicle Systems

    NASA Technical Reports Server (NTRS)

    Rich, Paul; McKinley, Bob; Jones, Greg

    2005-01-01

    Specific to the application of any technology to a vehicle, such as circulation control, it is important to understand the process that NASA is using to set its direction in research and development. To see how circulation control fits into any given NASA program requires the reader to understand NASA's Vehicle Systems (VS) Program. The VS Program recently celebrated its first year of existence with an annual review - an opportunity to look back on accomplishments, solicit feedback, expand national advocacy and support for the program, and recognize key contributions. Since its formation last year, Vehicle Systems has coordinated seven existing entities in a streamlined aeronautics research effort. It invests in vehicle technologies to protect the environment, make air travel more accessible and affordable for Americans, enable exploration through new aerospace missions, and augment national security. This past year has seen a series of valuable partnerships with industry, academia, and government agencies to make crucial aeronautics advances and assure America s future in flight.

  7. Chemical composition of tropospheric air masses encountered during high altitude flights (>11.5 km) during the 2009 fall Operation Ice Bridge field campaign

    NASA Astrophysics Data System (ADS)

    Yang, Mei Ying Melissa; Vay, Stephanie A.; Stohl, Andreas; Choi, Yonghoon; Diskin, Glenn S.; Sachse, Glen W.; Blake, Donald R.

    2012-09-01

    As part of the 2009 Operation Ice Bridge campaign, the NASA DC-8 aircraft was used to fill the data-time gap in laser observation of the changes in ice sheets, glaciers and sea ice between ICESat-I (Ice, Cloud, and land Elevation Satellite) and ICESat-II. Complementing the cryospheric instrument payload were four in situ atmospheric sampling instruments integrated onboard to measure trace gas concentrations of CO2, CO, N2O, CH4, water vapor and various VOCs (Volatile Organic Compounds). This paper examines two plumes encountered at high altitude (12 km) during the campaign; one during a southbound transit flight (13°S) and the other at 86°S over Antarctica. The data presented are especially significant as the Southern Hemisphere is heavily under-sampled during the austral spring, with few if any high-resolution airborne observations of atmospheric gases made over Antarctica. Strong enhancements of CO, CH4, N2O, CHCl3, OCS, C2H6, C2H2 and C3H8 were observed in the two intercepted air masses that exhibited variations in VOC composition suggesting different sources. The transport model FLEXPART showed that the 13°S plume contained predominately biomass burning emissions originating from Southeast Asia and South Africa, while both anthropogenic and biomass burning emissions were observed at 86°S with South America and South Africa as indicated source regions. The data presented here show evidence that boundary layer pollution is transported from lower latitudes toward the upper troposphere above the South Pole, which may not have been observed in the past.

  8. Sensitive monitoring of volatile chemical warfare agents in air by atmospheric pressure chemical ionization mass spectrometry with counter-flow introduction.

    PubMed

    Seto, Yasuo; Kanamori-Kataoka, Mieko; Tsuge, Koichiro; Ohsawa, Isaac; Iura, Kazumitsu; Itoi, Teruo; Sekiguchi, Hiroyuki; Matsushita, Koji; Yamashiro, Shigeharu; Sano, Yasuhiro; Sekiguchi, Hiroshi; Maruko, Hisashi; Takayama, Yasuo; Sekioka, Ryoji; Okumura, Akihiko; Takada, Yasuaki; Nagano, Hisashi; Waki, Izumi; Ezawa, Naoya; Tanimoto, Hiroyuki; Honjo, Shigeru; Fukano, Masumi; Okada, Hidehiro

    2013-03-01

    A new method for sensitively and selectively detecting chemical warfare agents (CWAs) in air was developed using counter-flow introduction atmospheric pressure chemical ionization mass spectrometry (MS). Four volatile and highly toxic CWAs were examined, including the nerve gases sarin and tabun, and the blister agents mustard gas (HD) and Lewisite 1 (L1). Soft ionization was performed using corona discharge to form reactant ions, and the ions were sent in the direction opposite to the airflow by an electric field to eliminate the interfering neutral molecules such as ozone and nitrogen oxide. This resulted in efficient ionization of the target CWAs, especially in the negative ionization mode. Quadrupole MS (QMS) and ion trap tandem MS (ITMS) instruments were developed and investigated, which were movable on the building floor. For sarin, tabun, and HD, the protonated molecular ions and their fragment ions were observed in the positive ion mode. For L1, the chloride adduct ions of L1 hydrolysis products were observed in negative ion mode. The limit of detection (LOD) values in real-time or for a 1 s measurement monitoring the characteristic ions were between 1 and 8 μg/m(3) in QMS instrument. Collision-induced fragmentation patterns for the CWAs were observed in an ITMS instrument, and optimized combinations of the parent and daughter ion pairs were selected to achieve real-time detection with LOD values of around 1 μg/m(3). This is a first demonstration of sensitive and specific real-time detection of both positively and negatively ionizable CWAs by MS instruments used for field monitoring. PMID:23339735

  9. Disinfecting Filters For Recirculated Air

    NASA Technical Reports Server (NTRS)

    Pilichi, Carmine A.

    1992-01-01

    Simple treatment disinfects air filters by killing bacteria, algae, fungi, mycobacteria, viruses, spores, and any other micro-organisms filters might harbor. Concept applied to reusable stainless-steel wire mesh filters and disposable air filters. Treatment used on filters in air-circulation systems in spacecraft, airplanes, other vehicles, and buildings to help prevent spread of colds, sore throats, and more-serious illnesses.

  10. On the North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    Schmitz, William J.; McCartney, Michael S.

    1993-02-01

    A new, speculative, and, we hope, provocative summary of the North Atlantic circulation is described, including both horizontal currents (wind-driven) and the primarily (thermohaline) meridional flows that involve the transformation of warm to cold water at high latitudes. Our picture is based on a synthesis of a variety of independent investigations that are contained in the literature as opposed to a presentation of the results of one technique or the point of view of one author. We describe a thermohaline cell (the so-called thermohaline conveyor belt) that is concentrated within the Atlantic and Southern oceans (rather than essentially global), with the most important upwelling sites being in the circumpolar and the equatorial current regimes. We concentrate on deep water formation and its replacement relative to intermediate-water formation. It has been pointed out recently that the formation of 13 Sv (1 Sv = 106 m³ s-1) of southward flowing North Atlantic Deep Water is compensated for in the upper ocean by northward cross-equatorial transport. We suggest that this thermocline layer flow passes through the Straits of Florida, transits the Gulf Stream system on its inshore side, and exits through the North Atlantic Current system after recirculation and modification. There is now a clear observational basis for the structure of recirculating gyres on the southern and northern sides of the Gulf Stream. We suggest a recirculation for the North Atlantic Current as well. We also describe a C-shaped component to the southern Gulf Stream recirculation and identify a roughly 10-Sv circulation in the eastern North Atlantic associated with the Azores Current. Recirculations play an important role in deep boundary current regimes and in water mass formation and modification. The transport of the deep western and northern boundary currents in the North Atlantic Ocean may be boosted (roughly doubled or tripled) by counterclockwise recirculating gyres and by additions of

  11. Characterizing the Atmospheric Circulation over the Colombian Orinoquia through Lagrangian Back-Trajectory Analysis

    NASA Astrophysics Data System (ADS)

    Orjuela, H. R.; Leon, G. E.; Jimenez-Pizarro, R.

    2012-12-01

    The ongoing transformation of the Colombian Orinoquia (Eastern Plains) due to the rapid expansion of the agricultural frontier and oil production implies a series of new atmospheric emissions, which might negatively impact human health and ecosystems in different ways. Some air pollutants have already been detected in the region. This is the case of Persistent Organic Pollutants (POPs), which are sampled in a site of the Global Atmospheric Passive Sampling (GAPS) network located in Arauca, Colombia. The current understanding on the origin and transport of pollutants is limited due to the lack of information on the atmospheric circulation in the Colombian Orinoquia. This research aims at generating new knowledge on the meteorology of this region mainly for weather forecasting and atmospheric pollution impact assessment. We present a conceptual model of the atmospheric circulation in the Colombian Orinoquia, including the main synoptic and mesoscale factors governing its meteorology. In order to identify the source of air masses and synoptic scale disturbances, we used Lagrangian back trajectories obtained with the model HYSPLIT 4.9 over the period 2000-2010. NCEP/NCAR and Global Data Assimilation System (GDAS) reanalysis results were used as meteorological input to HYSPLIT. Prior to the Lagrangian simulation, these global datasets were evaluated for their capability to reproduce meteorological observations in the region, particularly for rain and flood-triggering conditions. The observational data included satellite images and ground level network measurements by the Colombian Institute of Hydrology, Meteorology and Environmental Research (IDEAM). Windgridds and other data analysis tools were used.

  12. Gravitational Separation in the Stratosphere - A New Tracer of Atmospheric Circulation

    NASA Astrophysics Data System (ADS)

    Ishidoya, S.; Sugawara, S.; Morimoto, S.; Aoki, S.; Nakazawa, T.; Honda, H.; Murayama, S.

    2012-12-01

    As a basic knowledge of atmospheric science, it has been believed that the gravitational separation of atmospheric components is observable only in the atmosphere above the turbopause. Despite this common perception, we found, from high-precision measurements not only of the isotopic ratios of N2, O2 and Ar but also of the concentration of Ar, that the gravitational separation occurs significantly even in the stratosphere; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle stratosphere, corrected for the gravitational separation, showed the same mean air age as estimated from the CO2 concentration. Simulations with a 2-dimensional NCAR model (SOCRATES) also indicated that a relationship between the gravitational separation and the air age in the stratosphere would be affected by an enhancement of the Brewer-Dobson circulation due to global warming. Therefore, the gravitational separation would be usable as a new tracer for an understanding of atmospheric circulation in the stratosphere.

  13. Climate modelling: Northern Hemisphere circulation.

    PubMed

    Gillett, Nathan P

    2005-09-22

    Air pressure at sea level during winter has decreased over the Arctic and increased in the Northern Hemisphere subtropics in recent decades, a change that has been associated with 50% of the Eurasian winter warming observed over the past 30 years, with 60% of the rainfall increase in Scotland and with 60% of the rainfall decrease in Spain. This trend is inconsistent with the simulated response to greenhouse-gas and sulphate-aerosol changes, but it has been proposed that other climate influences--such as ozone depletion--could account for the discrepancy. Here I compare observed Northern Hemisphere sea-level pressure trends with those simulated in response to all the major human and natural climate influences in nine state-of-the-art coupled climate models over the past 50 years. I find that these models all underestimate the circulation trend. This inconsistency suggests that we cannot yet simulate changes in this important property of the climate system or accurately predict regional climate changes.

  14. AIRS-Light Instrument Concept and Critical Technology Development

    NASA Technical Reports Server (NTRS)

    Maschhoff, Kevin

    2001-01-01

    Understanding Earth's climate, atmospheric transport mechanisms, and the hydrologic cycle requires a precise knowledge of global atmospheric circulation, temperature profiles, and water vapor distribution. The accuracy of advanced sounders such as AIRS/AMSU/HSB on NASA's Aqua spacecraft can match radiosonde accuracy. It is essential to fold those capabilities fully into the NPOESS, enabling soundings of radiosonde accuracy, every 6 hours around the globe on an operational basis. However, the size, mass, power demands, and thermal characteristics of the Aqua sounding instrument suite cannot be accommodated on the NPOESS spacecraft. AIRS-Light is an instrument concept, developed under the Instrument Incubator Program, which provides IR sounding performance identical to the AIRS instrument, but uses advances in HgCdTe FPA technology and pulse tube cooler technology, as well as design changes to dramatically reduce the size, mass, and power demand, allowing AIRS-Light to meet all NPOESS spacecraft interface requirements. The instrument concept includes substantial re-use of AIRS component designs, including the complex AIRS FPA, to reduce development risk and cost. The AIRS-Light Instrument Incubator program fostered the development of photovoltaic-mode HgCdTe detector array technology for the 13.5-15.4 micron band covered by photoconductive-mode HgCdTe arrays in AIRS, achieved state of the art results in this band, and substantially reduced the development risk for this last new technology needed for AIRS-Light implementation, A demonstration of a prototype 14.5-15.4 micron band IRFPA in a reduced heat-load dewar together with the IMAS pulse tube cryocooler is in progress.

  15. Evaluation of chemical transport model predictions of primary organic aerosol for air masses classified by particle component-based factor analysis

    NASA Astrophysics Data System (ADS)

    Stroud, C. A.; Moran, M. D.; Makar, P. A.; Gong, S.; Gong, W.; Zhang, J.; Slowik, J. G.; Abbatt, J. P. D.; Lu, G.; Brook, J. R.; Mihele, C.; Li, Q.; Sills, D.; Strawbridge, K. B.; McGuire, M. L.; Evans, G. J.

    2012-09-01

    Observations from the 2007 Border Air Quality and Meteorology Study (BAQS-Met 2007) in Southern Ontario, Canada, were used to evaluate predictions of primary organic aerosol (POA) and two other carbonaceous species, black carbon (BC) and carbon monoxide (CO), made for this summertime period by Environment Canada's AURAMS regional chemical transport model. Particle component-based factor analysis was applied to aerosol mass spectrometer measurements made at one urban site (Windsor, ON) and two rural sites (Harrow and Bear Creek, ON) to derive hydrocarbon-like organic aerosol (HOA) factors. A novel diagnostic model evaluation was performed by investigating model POA bias as a function of HOA mass concentration and indicator ratios (e.g. BC/HOA). Eight case studies were selected based on factor analysis and back trajectories to help classify model bias for certain POA source types. By considering model POA bias in relation to co-located BC and CO biases, a plausible story is developed that explains the model biases for all three species. At the rural sites, daytime mean PM1 POA mass concentrations were under-predicted compared to observed HOA concentrations. POA under-predictions were accentuated when the transport arriving at the rural sites was from the Detroit/Windsor urban complex and for short-term periods of biomass burning influence. Interestingly, the daytime CO concentrations were only slightly under-predicted at both rural sites, whereas CO was over-predicted at the urban Windsor site with a normalized mean bias of 134%, while good agreement was observed at Windsor for the comparison of daytime PM1 POA and HOA mean values, 1.1 μg m-3 and 1.2 μg m-3, respectively. Biases in model POA predictions also trended from positive to negative with increasing HOA values. Periods of POA over-prediction were most evident at the urban site on calm nights due to an overly-stable model surface layer. This model behaviour can be explained by a combination of model under

  16. The main characteristics of atmospheric circulation associated with fog in Greece

    NASA Astrophysics Data System (ADS)

    Houssos, E. E.; Lolis, C. J.; Bartzokas, A.

    2009-11-01

    The characteristics of the atmospheric circulation over Europe and the Mediterranean associated with the formation and the dissipation of fog in Greece are examined. The data used consists of: i) 3-hourly meteorological observations recorded at 16 meteorological stations in Greece and ii) daily (00:00 UTC) 2.5×2.5 grid point values of mean sea-level pressure, 500 hPa geopotential height, 850 hPa and 500 hPa air temperatures and 1000-500 hPa thickness over Europe for the period 1957-2002. 1055 fog events are extracted from the 3-hourly meteorological observations. A specific methodology scheme including S-mode Factor Analysis and k-means Cluster Analysis is applied to the grid point data sets for the first day of a fog event (D day), the day prior to D day (D-1 day) and the day that follows the last day of a fog event (END day) and the 1055 evolutions of the atmospheric circulation associated with fog events in Greece are classified into 10 clusters. The mean patterns of MSL Pressure, 850 hPa and 500 hPa air temperatures, 1000-500 hPa thickness and 500 hPa geopotential height show that in most of the clusters, the presence of anticyclonic conditions over the Balkans, a warm front passage, or a weak, humid southerly flow induced by the presence of a shallow depression over the western Mediterranean favor fog formation in Greece, while the dissipation of fog occurs when drier air masses are transferred over the Balkans. The main differences among the 10 clusters refer to the exact position, the intensity and the specific evolution of the surface and the upper air systems, the season of their predominance and the area of the Greek territory that mainly refer to.

  17. Monitoring coastal water properties and current circulation with ERTS-1

    NASA Technical Reports Server (NTRS)

    Klemas, V.; Otley, M.; Wethe, C.; Rogers, R. H.

    1977-01-01

    Imagery and digital tapes from nine successful ERTS-1 passes over Delaware Bay during different portions of the tidal cycle were analyzed with special emphasis on turbidity, current circulation, waste disposal plumes, and convergent boundaries between different water masses. ERTS-1 image radiance correlated well with Secchi depth and suspended sediment concentration. Circulation patterns observed by ERTS-1 during different parts of the tidal cycle, agreed well with predicted and measured currents throughout Delaware Bay.

  18. Online volatile organic compound measurements using a newly developed proton-transfer ion-trap mass spectrometry instrument during New England Air Quality Study--Intercontinental Transport and Chemical Transformation 2004: performance, intercomparison, and compound identification.

    PubMed

    Warneke, Carsten; Kato, Shuji; De Gouw, Joost A; Goldan, Paul D; Kuster, William C; Shao, Min; Lovejoy, Edward R; Fall, Ray; Fehsenfeld, Fred C

    2005-07-15

    We have used a newly developed proton-transfer ion-trap mass spectrometry (PIT-MS) instrument for online trace gas analysis of volatile organic compounds (VOCs) during the 2004 New England Air Quality Study-Intercontinental Transport and Chemical Transformation study. The PIT-MS instrument uses proton-transfer reactions with H3O+ ions to ionize VOCs, similarto a PTR-MS (proton-transfer reaction mass spectrometry) instrument but uses an ion trap mass spectrometer to analyze the product ions. The advantages of an ion trap are the improved identification of VOCs and a near 100% duty cycle. During the experiment, the PIT-MS instrument had a detection limit between 0.05 and 0.3 pbbv (S/N = 3 (signal-to-noise ratio)) for 2-min integration time for most tested VOCs. PIT-MS was used for ambient air measurements onboard a research ship and agreed well with a gas chromatography mass spectrometer). The comparison included oxygenated VOCs, aromatic compounds, and others such as isoprene, monoterpenes, acetonitrile, and dimethyl sulfide. Automated collision-induced dissociation measurements were used to determine the contributions of acetone and propanal to the measured signal at 59 amu; both species are detected at this mass and are thus indistinguishable in conventional PTR-MS.

  19. World Ocean Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Clarke, R. Allyn

    1992-01-01

    The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

  20. The method for on-site determination of trace concentrations of methyl mercaptan and dimethyl sulfide in air using a mobile mass spectrometer with atmospheric pressure chemical ionization, combined with a fast enrichment/separation system.

    PubMed

    Kudryavtsev, Andrey S; Makas, Alexey L; Troshkov, Mikhail L; Grachev, Mikhail А; Pod'yachev, Sergey P

    2014-06-01

    A method for fast simultaneous on-site determination of methyl mercaptan and dimethyl sulfide in air was developed. The target compounds were actively collected on silica gel, followed by direct flash thermal desorption, fast separation on a short chromatographic column and detection by means of mass spectrometer with atmospheric pressure chemical ionization. During the sampling of ambient air, water vapor was removed with a Nafion selective membrane. A compact mass spectrometer prototype, which was designed earlier at Trofimuk Institute of Petroleum Geology and Geophysics, was used. The minimization of gas load of the atmospheric pressure ion source allowed reducing the power requirements and size of the vacuum system and increasing its ruggedness. The measurement cycle is about 3 min. Detection limits in a 0.6 L sample are 1 ppb for methyl mercaptan and 0.2 ppb for dimethyl sulfide.