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Sample records for air mass movement

  1. Air movement preferences observed in office buildings.

    PubMed

    Zhang, Hui; Arens, Edward; Fard, Sahar Abbaszadeh; Huizenga, Charlie; Paliaga, Gwelen; Brager, Gail; Zagreus, Leah

    2007-05-01

    Office workers' preferences for air movement have been extracted from a database of indoor environmental quality surveys performed in over 200 buildings. Dissatisfaction with the amount of air motion is very common, with too little air movement cited far more commonly than too much air movement. Workers were also surveyed in a detailed two-season study of a single naturally ventilated building. About one-half the building's population wanted more air movement and only 4% wanted less. This same ratio applied when the air movement in workspaces was higher than 0.2 m/s, the de facto draft limit in the current ASHRAE and ISO thermal environment standards. Preference for "less air motion" exceeded that for "more" only at thermal sensations of -2 (cool) or colder. These results raise questions about the consequences of the ASHRAE and ISO standards' restrictions on air movement, especially for neutral and warm conditions.

  2. Air movement preferences observed in office buildings

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Arens, Edward; Fard, Sahar Abbaszadeh; Huizenga, Charlie; Paliaga, Gwelen; Brager, Gail; Zagreus, Leah

    2007-05-01

    Office workers’ preferences for air movement have been extracted from a database of indoor environmental quality surveys performed in over 200 buildings. Dissatisfaction with the amount of air motion is very common, with too little air movement cited far more commonly than too much air movement. Workers were also surveyed in a detailed two-season study of a single naturally ventilated building. About one-half the building’s population wanted more air movement and only 4% wanted less. This same ratio applied when the air movement in workspaces was higher than 0.2 m/s, the de facto draft limit in the current ASHRAE and ISO thermal environment standards. Preference for “less air motion” exceeded that for “more” only at thermal sensations of -2 (cool) or colder. These results raise questions about the consequences of the ASHRAE and ISO standards’ restrictions on air movement, especially for neutral and warm conditions.

  3. PM10-bound polycyclic aromatic hydrocarbons in Chiang Mai (Thailand): Seasonal variations, source identification, health risk assessment and their relationship to air-mass movement

    NASA Astrophysics Data System (ADS)

    Wiriya, Wan; Prapamontol, Tippawan; Chantara, Somporn

    2013-04-01

    found that vehicle emission and biomass burning were the main sources of PM10 and PAHs in this area. The high ratio value of benzo(a)anthracene/chrysene (BaA/CHR) in the dry season of 2010 indicated possible photochemical processes and long distance emissions. Findings on source identification of PM10 and PAHs were found to be relevant to the direction and speed of air mass movement run by backward trajectory.

  4. Mass movement slope streaks imaged by the Mars Orbiter Camera

    NASA Astrophysics Data System (ADS)

    Sullivan, Robert; Thomas, Peter; Veverka, Joseph; Malin, Michael; Edgett, Kenneth S.

    2001-10-01

    Narrow, fan-shaped dark streaks on steep Martian slopes were originally observed in Viking Orbiter images, but a definitive explanation was not possible because of resolution limitations. Pictures acquired by the Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor (MGS) spacecraft show innumerable examples of dark slope streaks distributed widely, but not uniformly, across the brighter equatorial regions, as well as individual details of these features that were not visible in Viking Orbiter data. Dark slope streaks (as well as much rarer bright slope streaks) represent one of the most widespread and easily recognized styles of mass movement currently affecting the Martian surface. New dark streaks have formed since Viking and even during the MGS mission, confirming earlier suppositions that higher contrast dark streaks are younger, and fade (brighten) with time. The darkest slope streaks represent ~10% contrast with surrounding slope materials. No small outcrops supplying dark material (or bright material, for bright streaks) have been found at streak apexes. Digitate downslope ends indicate slope streak formation involves a ground-hugging flow subject to deflection by minor topographic obstacles. The model we favor explains most dark slope streaks as scars from dust avalanches following oversteepening of air fall deposits. This process is analogous to terrestrial avalanches of oversteepened dry, loose snow which produce shallow avalanche scars with similar morphologies. Low angles of internal friction typically 10-30¡ for terrestrial loess and clay materials suggest that mass movement of (low-cohesion) Martian dusty air fall is possible on a wide range of gradients. Martian gravity, presumed low density of the air fall deposits, and thin (unresolved by MOC) failed layer depths imply extremely low cohesive strength at time of failure, consistent with expectations for an air fall deposit of dust particles. As speed increases during a dust avalanche, a

  5. Early Warning at the Gradenbach Mass Movement

    NASA Astrophysics Data System (ADS)

    Lienhart, Werner; Lang, Erich; Mertl, Stefan; Stary, Ulrike; Brückl, Ewald

    2013-04-01

    The Gradenbach mass movement (GMM) is an example of a deep seated gravitational slope deformation in the crystalline rocks of the Eastern Alps (12.85° E, 47.00° N). The main body of the GMM covers an area of 1.7km2 and comprises a volume of 0.12km3. The main scarp is located below the mountain crest at an elevation of 2235m. The toe is at 1200m elevation in the Gradenbach valley. The GMM became active during the second half of the 19th century according to historic documents. Quantitative data about the movement are available since 1962. Quasi-stationary phases of creep or slow sliding were interrupted by accelerations in 1965-1966, 1975, 2001, and 2009 yielding a total displacement of about 20m. The cumulative displacement during the high velocity phases was about 8m in 1965/66 and about 1m in 2001 and 2009. A transition to rapid and catastrophic sliding cannot be excluded during the acceleration phases in the future. The early warning system of the Gradenbach Observatory at the GMM consists of a geodetic, a hydro-meteorological, and a seismological component. The geodetic component comprises a GPS network with stations distributed over the whole GMM and two wire-extensometers recording the displacement at the toe of the landslide relative to the opposite slope. The GPS data are available in real time. The extensometer data are currently transmitted in weekly intervals. The hydro-meteorological component comprises the real time registration and data transmission of precipitation and temperature at one station on the GMM. The water equivalent of the snow cover is weekly determined at 15 profiles. Snow melt and infiltration into the GMM are estimated from this data. The hydrostatic water level is measured at two borehole gauges. A proxy of the hydrostatic water level at the surface of rupture is derived from the hydro-meteorological data and related to the velocity of the GMM by a power law. Investigations show that a variation of the hydrostatic water level at

  6. Prison Meditation Movements and Mass Incarceration.

    PubMed

    Lyons, Thomas; Cantrell, W Dustin

    2016-09-01

    By some estimates, more than half of inmates held in jails and prisons in the United States have a substance use disorder. Treatments involving the teaching of meditation and other contemplative practices have been developed for a variety of physical and mental disorders, including drug and alcohol addiction. At the same time, an expanding volunteer movement across the country has been bringing meditation and yoga into jails and prisons. This review first examines the experimental research on one such approach-mindfulness meditation as a treatment for drug and alcohol addiction, as well as the research on mindfulness in incarcerated settings. We argue that to make a substantial impact on recidivism, such programs must mirror volunteer programs which emphasize interdependency and non-duality between the "helper" and the "helped," and the building of meditation communities both inside and outside of prison.

  7. 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.

  8. Rainfall intensity-duration conditions for mass movements in Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Chi-Wen; Saito, Hitoshi; Oguchi, Takashi

    2015-12-01

    Mass movements caused by rainfall events in Taiwan are analyzed during a 7-year period from 2006 to 2012. Data from the Taiwan Soil and Water Conservation Bureau reports were compiled for 263 mass movement events, including 156 landslides, 91 debris flows, and 16 events with both landslides and debris flows. Rainfall totals for each site location were obtained from interpolated rain gauge data. The rainfall intensity-duration ( I-D) relationship was examined to establish a rainfall threshold for mass movements using random sampling: I = 18.10(±2.67) D -0.17(±0.04), where I is mean rainfall intensity (mm/h) and D is the time (h) between the beginning of a rainfall event and the resulting mass movement. Significant differences were found between rainfall intensities and thresholds for landslides and debris flows. For short-duration rainfall events, higher mean rainfall intensities were required to trigger debris flows. In contrast, for long-duration rainfall events, similar mean rainfall intensities triggered both landslides and debris flows. Mean rainfall intensity was rescaled by mean annual precipitation (MAP) to define a new threshold: I MAP = 0.0060(±0.0009) D -0.17(±0.04), where I MAP is rescaled rainfall intensity and MAP is the minimum for mountainous areas in Taiwan (3000 mm). Although the I-D threshold for Taiwan is high, the I MAP -D threshold for Taiwan tends to be low relative to other areas around the world. Our results indicate that Taiwan is highly prone to rainfall-induced mass movements. This study also shows that most mass movements occur in high rainfall-intensity periods, but some events occur before or after the rainfall peak. Both antecedent and peak rainfall play important roles in triggering landslides, whereas debris flow occurrence is more related to peak rainfall than antecedent rainfall.

  9. Seismic stratigraphy of giant mass movements on actual margins

    SciTech Connect

    Coumes, F.

    1986-05-01

    Recent geophysical surveys of different marine slopes show distinct figures corresponding to sliding, slumping, and creeping processes. The comparison of these phenomena is made on the basis of a seismic interpretation of gravity events in distinct margins and basins such as Indian Ocean, China Sea, Tasman Sea, and Mediterranean Sea. The distinction between such phenomena is sometimes difficult, but some features seem characteristic of a slow movement of the sedimentary cover on low-angle slopes. This distinction is important, considering the reservoir potential of the sedimentary cover involved in the phenomena. In instantaneous events such as sliding, the successive processes following this first step lead in a final stage to a potential reservoir (such as the Bouma sequence). However, slow mass movement on slopes destroys the internal structure to finalize into chaotic or transparent layers that can be misinterpreted as sedimentary reservoirs.

  10. THE EFFECTS OF BUILDING FEATURES ON INDOOR AIR AND POLLUTANT MOVEMENTS

    EPA Science Inventory

    The paper discusses full-scale residential building tests to determine the effects of building features on indoor air and pollutant movement. It was found that the activated heating and air-conditioning (HAC) system served as a conductor that enhanced the indoor air movement and ...

  11. Modeling rapid mass movements using the shallow water equations

    NASA Astrophysics Data System (ADS)

    Hergarten, S.; Robl, J.

    2014-11-01

    We propose a new method to model rapid mass movements on complex topography using the shallow water equations in Cartesian coordinates. These equations are the widely used standard approximation for the flow of water in rivers and shallow lakes, but the main prerequisite for their application - an almost horizontal fluid table - is in general not satisfied for avalanches and debris flows in steep terrain. Therefore, we have developed appropriate correction terms for large topographic gradients. In this study we present the mathematical formulation of these correction terms and their implementation in the open source flow solver GERRIS. This novel approach is evaluated by simulating avalanches on synthetic and finally natural topographies and the widely used Voellmy flow resistance law. The results are tested against analytical solutions and the commercial avalanche model RAMMS. The overall results are in excellent agreement with the reference system RAMMS, and the deviations between the different models are far below the uncertainties in the determination of the relevant fluid parameters and involved avalanche volumes in reality. As this code is freely available and open source, it can be easily extended by additional fluid models or source areas, making this model suitable for simulating several types of rapid mass movements. It therefore provides a valuable tool assisting regional scale natural hazard studies.

  12. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  13. 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…

  14. Mass movements on Venus - Preliminary results from Magellan cycle 1 observations

    NASA Astrophysics Data System (ADS)

    Malin, Michael C.

    1992-10-01

    A preliminary assessment of mass movements and their geomorphic characteristics as determined from visual inspection of Magellan cycle 1 synthetic aperture radar images is described. The primary data set was a catalog of over 200 ten-inch square photographic prints of full-resolution mosaic image data records. Venus exhibits unambiguous evidence of mass movements at a variety of scales. Mass movements appear mostly in the form of block and rock movements; there is little evidence of regolith and sediment movements. Unique Venusian conditions may play a role in the creation of some mass movement features. Dark (smooth) surfaces surrounding many rockslide avalanches are probably fine materials emplaced as part of the mass movement process, as airfall, surface-hugging density flows, or coarse-depleted debris flows. The size and efficiency of emplacement of landslide deposits on Venus are comparable to those seen on Mars, which in turn generally resemble terrestrial occurrences.

  15. Mass movements on Venus - Preliminary results from Magellan cycle 1 observations

    NASA Technical Reports Server (NTRS)

    Malin, Michael C.

    1992-01-01

    A preliminary assessment of mass movements and their geomorphic characteristics as determined from visual inspection of Magellan cycle 1 synthetic aperture radar images is described. The primary data set was a catalog of over 200 ten-inch square photographic prints of full-resolution mosaic image data records. Venus exhibits unambiguous evidence of mass movements at a variety of scales. Mass movements appear mostly in the form of block and rock movements; there is little evidence of regolith and sediment movements. Unique Venusian conditions may play a role in the creation of some mass movement features. Dark (smooth) surfaces surrounding many rockslide avalanches are probably fine materials emplaced as part of the mass movement process, as airfall, surface-hugging density flows, or coarse-depleted debris flows. The size and efficiency of emplacement of landslide deposits on Venus are comparable to those seen on Mars, which in turn generally resemble terrestrial occurrences.

  16. Evolution of Southern Hemisphere spring air masses observed by HALOE

    NASA Technical Reports Server (NTRS)

    Pierce, R. Bradley; Grose, William L.; Russell, James M., III; Tuck, Adrian F.

    1994-01-01

    The evolution of Southern Hemisphere air masses observed by the Halogen Occultation Experiment (HALOE) during September 21 through October 15, 1992, is investigated using isentropic trajectories computed from United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures. Maps of constituent concentrations are obtained by accumulation of air masses from previous HALOE occultations. Lagged correlations between initial and subsequent HALOE observations of the same air mass are used to validate the air mass trajectories. High correlations are found for lag times as large as 10 days. Frequency distributions of the air mass constituent concentrations are used to examine constituent distributions in and around the Southern Hemisphere polar vortex.

  17. Evaluation of the Army’s Plan for Tailoring Its Forces for Air Movement

    DTIC Science & Technology

    1963-11-01

    essential part of the overall plan for tailoring Army forces for movement by air . The principal advantage of this concept allows the option of rapidly...Tailoring Its Forces For Air l^ovement# :p^ Inventoried * Retention Justified Library J tf Headquarters, U.S. Aray ^ I luitw.j of Cus...Tailoring its Forces for Air Movement (U)" TO: Assistant Chief of Staff for Force Development Department of the Army ATTN: DOT DO 3 Washington, D. C

  18. Movement simulation of the variable masses in the Gylden-Meshcherskii problem

    SciTech Connect

    Starinova, Olga L.; Salmin, Vadim V.

    2014-12-10

    The Gylden-Meshcherskii problem is used for various cases of dynamics of two points of the variable mass. For example, it describes of double star evolution due to mass loss at the photon expense and the corpuscular activity. Except, it is mathematical model for the movement of spacecraft with propulsion system. In the present work the mass variation laws, allowing a stationary form of the movement differential equations are considered. Movement simulation for all cases was conducted. The relative movement trajectories was constructed as for known Eddington-Jeans laws and for other mass variation laws.

  19. Subaqueous Mass movements in Lake Mjøsa, Norway

    NASA Astrophysics Data System (ADS)

    Forsberg, C. F.; Heyerdahl, H.; Solheim, A.

    2010-12-01

    Lake Mjøsa is Norway’s largest lake (117 km long, area: 365 km2, greatest depth 468 m). It lies in a depression formed by glacial over-deepening of the southward extension of the Gudbrandsdalen glacial valley. It is therefore characterized by typical glacial ”U-shaped” cross sections. In the study area it almost annually covered by winter ice. The present study arose from pipeline breakages near the city of Gjøvik that ROV inspections demonstrated were caused by subaqueous mass movements. The purpose of the study was suggest new pipeline routes based on slope stability evaluations from morphological analyses supplemented by simple geotechnical testing of core samples. Data consisted of a multibeam bathymetric survey of the study area, a grid of sub-bottom profiler lines (SES 2000) and 9 gravity cores. The morphological analysis of the multibeam data revealed that lake bed has slopes between ~15° and ~35° from the coastline and into the central deep (~250 m in the study area). Numerous flow paths were identified as were areas offshore from river mouths with clear evidence of downslope mass transport. Several slide scarps from 1 to 3 m were also discovered. Slope stability analyses reveal safety factors close to 1 for the steepest gradients. The submarine slides are therefore thought to have been caused by density currents of cold water formed during winter. This dense water flowed down slope along the flow paths and is beleived to erosively undercut the soft seafloor sediments which thereby lost their downslope support. New pipeline corridors were drawn to avoid such scenarios.

  20. A laboratory study on groundwater quality and mass movement occurrence

    NASA Astrophysics Data System (ADS)

    Fan, Jen-Chen; Liu, Che-Hsin; Yang, Chih-Hsiang; Huang, Hsiao-Yu

    2009-06-01

    In this study, soil samples collected from the sides of two streams with high debris flow potential at Shenmu and Fengchiou village in Nantou County, Taiwan, were used for seepage tank tests in the laboratory. While the tests were being conducted, observations were made to investigate the relationships among displacement of the slope, quality of the seepage water and occurrence of mass movement. The results showed that according to the change rate, displacement could be divided into two stages, namely, the initial failure displacement stage and primary failure displacement stage. While the displacement of the slope was in primary failure displacement stages, the probability of slope failure became much higher. Before general slope failure, electrical conductivity (EC) and sulfate ion (SO4 2-) concentration of the seepage water increased significantly. The time when EC of the seepage water started to increase rapidly was much earlier than that when displacement of the slope started to increase significantly. Therefore, from the hazard mitigation view, there will be a longer time for response if EC of the seepage water was monitored.

  1. Catastrophic glacial multi-phase mass movements: a special type of glacial hazard

    NASA Astrophysics Data System (ADS)

    Petrakov, D. A.; Chernomorets, S. S.; Evans, S. G.; Tutubalina, O. V.

    2008-04-01

    Many glacier-related hazards are well typified and studied, but some events stand out from conventional classifications. The Kolka-Karmadon catastrophic event on 20 September 2002 in North Ossetia, North Caucasus, Russia is used as an example of a complex glacier failure exhibiting characteristics such as high mobility, long runout, ultrarapid movement and multiphase behaviour. We consider terminology protocol for glacier hazard classification and then, using the Kolka-Karmadon event and several other examples from around the world, we propose a new term for this family of events. Catastrophic glacier multi-phase mass movement (CGMM) is described and further illustrated by eight major events from Russia, Georgia, Peru, Chile, and Canada. CGMM have a combination of specific features: extraordinary velocities and long-distance runout despite low path angle; progressive fluidisation along travel path; superelevation and run-up of the moving mass, air blast wave in the avalanche flow phase; entrainment of available materials in its path, and the repeated nature of the event. CGMM events may affect areas remote from glaciers which were previously considered as safe.

  2. Evolution of Mass Movements near Epicentre of Wenchuan Earthquake, the First Eight Years

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Zhang, Limin; Lacasse, Suzanne; Nadim, Farrokh

    2016-11-01

    It is increasingly clear that landslides represent a major cause of economic costs and deaths in earthquakes in mountains. In the Wenchuan earthquake case, post-seismic cascading landslides continue to represent a major problem eight years on. Failure to anticipate the impact of cascading landslides could lead to unexpected losses of human lives and properties. Previous studies tended to focus on separate landslide processes, with little attention paid to the quantification of long-term evolution of multiple processes or the evolution of mass movements. The very active mass movements near the epicentre of the Wenchuan earthquake provided us a unique opportunity to understand the complex processes of the evolving cascading landslides after a strong earthquake. This study budgets the mass movements on the hillslopes and in the channels in the first eight years since the Wenchuan earthquake and verify a conservation in mass movements. A system illustrating the evolution and interactions of mass movement after a strong earthquake is proposed.

  3. Evolution of Mass Movements near Epicentre of Wenchuan Earthquake, the First Eight Years.

    PubMed

    Zhang, Shuai; Zhang, Limin; Lacasse, Suzanne; Nadim, Farrokh

    2016-11-08

    It is increasingly clear that landslides represent a major cause of economic costs and deaths in earthquakes in mountains. In the Wenchuan earthquake case, post-seismic cascading landslides continue to represent a major problem eight years on. Failure to anticipate the impact of cascading landslides could lead to unexpected losses of human lives and properties. Previous studies tended to focus on separate landslide processes, with little attention paid to the quantification of long-term evolution of multiple processes or the evolution of mass movements. The very active mass movements near the epicentre of the Wenchuan earthquake provided us a unique opportunity to understand the complex processes of the evolving cascading landslides after a strong earthquake. This study budgets the mass movements on the hillslopes and in the channels in the first eight years since the Wenchuan earthquake and verify a conservation in mass movements. A system illustrating the evolution and interactions of mass movement after a strong earthquake is proposed.

  4. Isentropic analysis of polar cold air mass streams

    NASA Astrophysics Data System (ADS)

    Iwasaki, Toshiki; Kanno, Yuki

    2015-04-01

    1. Introduction A diagnostic method is presented of polar cold air mass streams defined below a threshold potential temperature. The isentropic threshold facilitates a Lagrangian view of the cold air mass streams from diabatic generation to disappearance. 2. Mass-weighted isentropic zonal mean (MIM) cold air streams In winter hemispheres, MIM's mass stream functions show a distinct extratropical direct (ETD) cell in addition to the Hadley cell. The mass stream functions have local maxima at around (280K, 45N) for NH winter and, around (280K, 50S) for SH winter. Thus, =280K may be appropriate to a threshold of the polar cold air mass for both hemispheres. The high-latitude downward motion indicates the diabatic generation of cold air mass, whereas the mid-latitude equatorward flow does its outbreak. The strength of equatorward flow is under significant control of wave-mean flow interactions. 3. Geographical distribution of the cold air mass streams in the NH winter In the NH winter, the polar cold air mass flux has two distinct mainstreams, hereafter called as East Asian (EA) stream and the North American (NA) stream. The former grows over the northern part of the Eurasian continent, turns down southeastward toward East Asia and disappears over the western North Pacific Ocean. The latter grows over the Arctic Ocean, flows toward the East Coast of North America and disappears over the western North Atlantic Ocean. These coincide well with main routes of cold surges. 4. Comparison between NH and SH winter streams The cold air mass streams in NH winter are more asymmetric than those in SH winter. The NH total cold air mass below =280K is about 1.5 times greater than the SH one. These come mainly from the topography and land-sea distribution. The mid-latitude mountains steer the cold air mass streams on the northern sides and enhance the residence time over its genesis region.

  5. An analysis of trichloroethylene movement in groundwater at castle Air Force Base, California

    USGS Publications Warehouse

    Avon, L.; Bredehoeft, J.D.

    1989-01-01

    A trichloroethylene (TCE) plume has been identified in the groundwater under a U.S. Air Force Base in the Central Valley of California. An areal, two-dimensional numerical solute transport model indicates that the movement of TCE due to advection, dispersion, and linear sorption is simulated over a 25-year historic period. The model is used in several ways: (1) to estimate the extent of the plume; (2) to confirm the likely sources of contamination as suggested by a soil organic vapor survey of the site; and (3) to make predictions about future movement of the plume. Despite the noisy and incomplete data set, the model reproduces the general trends in contamination at a number of observation wells. The analysis indicates that soil organic vapor monitoring is an effective tool for identifying contaminant source locations. Leaky sewer pipes and underground tanks are the indicated pathways for TCE to have entered the groundwater system. The chemical mass balance indicates that a total of about 100 gallons of TCE - a relatively small amount of organic solvent - has created the observed groundwater plume. ?? 1989.

  6. Prospective impact of forest fire on Mass Movement events

    NASA Astrophysics Data System (ADS)

    Ziade, Rouba; Abdallah, Chadi; Baghdadi, Nicolas

    2013-04-01

    Mass Movement (MM) has always been one of the main natural hazards that threatened both the natural and human environments of Lebanon and their occurrence has increased by almost 60% between 1956 and 2008. On the other hand, Forest Fire (FF) has emerged to impose as another natural hazard that has destroyed more than 25 % of Lebanon's forests in less than 40 years. The increased FF occurrence is one of the potential detrimental impacts of anthropogenic climate change where high temperatures and current-year drought are strongly associated with an increase in the number of fires and area burned in a variety of forest types. A simple observation shows the coincident trends between MM and FF. This paper investigates the potential impact of FF on MM occurrence in Damour and Nahr Ibrahim watersheds in Lebanon. Preconditioning factors taken into consideration were topography, soil, geology, mean annual precipitation and land cover maps. MM and FF inventory maps were produced through Remote Sensing (RS) using aerial (1956 and 2008) and satellite images (2005 and 2011) in addition to Google Earth Timeline. Furthermore, FF was introduced as the inducing factor whose impact was assessed by the calculation of FF burn severity. This burn severity was extracted from Landsat images (1986-2011) through the Normalized Burn Ratio (NBR) index. A field study was carried out in order to substantiate the MM inventory. Furthermore, the burn index maps were validated through the Mini-Disk Infiltrometer (MDI), a device which supplies the soil infiltration rate usually after a fire. Following the standardization of the impact factors into layers using Geographic Information System (GIS), the relative importance of these layers for causing MM has been evaluated using modified InfoVal method and a MM Susceptibility Map (MMSM) was generated. Hence, every factor obtained a weight that shows its impact on MM occurrence. Preceded only by Land Cover change, NBR obtained the highest weight making

  7. YANGTZE project: Investigation of mass movements in the Three Gorges Reservoir Area (P. R. China)

    NASA Astrophysics Data System (ADS)

    Ehret, Dominik; Rohn, Joachim; Wiedenmann, Johannes; Rudolph, René; Otte, Karel; Ernstberger, Stefanie; Eckstein, Susan; Dumperth, Christian

    2010-05-01

    Within the German YANGTZE Project, mass movement hazard is investigated for the Xiangxi Catchment which is part of the Three Gorges Reservoir (P. R. China). The objective of our sub-project is to investigate the impact of the Three Gorges Reservoir on slope stability and (re-)activation of mass movements. Within this paper first results of investigations on mass movements in the Xiangxi Catchment that were started in summer 2008 are presented. They show a significant correlation between mass movement distribution and activity on the one hand and lithology and altitude on the other hand. In Xiangxi Catchment, correlation between geology and occurrence of mass movements can be studied ideally as most of the geological formations outcropping in the reservoir area can be found there. Furthermore, the mouth of Xiangxi River is quite close to the Three Gorges Dam so that the impact of the impoundment is distinctive in the Xiangxi Catchment. In 2008 and 2009, about 70 km² were mapped geotechnically. The mapping was done for (a) the backwater area of Xiangxi River influenced by the impoundment of the Three Gorges Reservoir (from Yangtze River to Gaoyang Town), (b) Quyuan Valley as a sub-catchment of Xiangxi Catchment, and (c) along the main roads from Gaoyang Town towards Gufu City and towards Shennongjia Nature Reserve. The investigated area comprises marine and continental sedimentary layers from Cambrian to Jurassic Period. The lithology of these layers is dominated by carbonates (limestone, dolostone and marlstone) on the one hand and clastic sediments (shale, mudstone, siltstone, sandstone, and conglomerate) on the other hand. A total of 180 mass movements was found and mapped. Mainly rotational or combined rotational-translational landslides, but also some rockslides and rockfalls were found. As expected, a strong correlation between lithology on the one side and occurrence and activity of mass movements on the other side could be found. In the study area, Jurassic

  8. The Relationship between Fundamental Movement Skills and Body Mass Index in Korean Preschool Children

    ERIC Educational Resources Information Center

    Kim, Chung-Il; Lee, Kang-Yi

    2016-01-01

    Early childhood obesity is a serious worldwide problem, and fundamental movement skills (FMS) are very important factors in human movement. Thus, several advanced studies have examined the associations between FMS and body mass index (BMI). The purpose of this study was to investigate BMI and FMS (locomotion and object control skills) in Korean…

  9. A study of the air movement in two aircraft-engine cylinders

    NASA Technical Reports Server (NTRS)

    Lee, Dana W

    1940-01-01

    Studies were made of the air movements in the NACA glass-cylinder apparatus using cylinder heads similar to those on the Wright R-1820-G engine and the Pratt & Whitney Wasp engine as modified by the Eclipse Aviation Corporation to use fuel-injection equipment. The air movements were made visible by mixing small feathers with the air; high-speed motion pictures were than taken of the feathers as they swirled about the inside the glass cylinder. The test engine speeds were 350, 500, and 1,000 r.p.m. Motion pictures were also taken of gasoline sprays injected into the cylinder during the intake stroke. The air flow produced by each cylinder head is described and some results of the velocity measurements of feathers are presented. The apparent time intervals required for vaporization of the gasoline sprays are also given.

  10. Thermal comfort, perceived air quality, and cognitive performance when personally controlled air movement is used by tropically acclimatized persons.

    PubMed

    Schiavon, S; Yang, B; Donner, Y; Chang, V W-C; Nazaroff, W W

    2016-10-18

    In a warm and humid climate, increasing the temperature set point offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature set point. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29°C and in the latter two cases with and without occupant-controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms, and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26°C and 29°C than at the common set point of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26°C; at 29°C, the availability of an occupant-controlled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature set point of 23°C yielded the lowest cognitive performance. An elevated set point in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates.

  11. Movement.

    ERIC Educational Resources Information Center

    Roberts, Lynda S.

    This document summarizes 20 articles and books which stress the importance of movement in the overall development of the human species. Each summary ranges in length from 100 to 200 words and often includes direct quotations. A wide range of movement activities suitable for people of all ages (from infants to adults) are discussed. Many summaries…

  12. Climate change impacts on mass movements--case studies from the European Alps.

    PubMed

    Stoffel, M; Tiranti, D; Huggel, C

    2014-09-15

    This paper addresses the current knowledge on climate change impacts on mass movement activity in mountain environments by illustrating characteristic cases of debris flows, rock slope failures and landslides from the French, Italian, and Swiss Alps. It is expected that events are likely to occur less frequently during summer, whereas the anticipated increase of rainfall in spring and fall could likely alter debris-flow activity during the shoulder seasons (March, April, November, and December). The magnitude of debris flows could become larger due to larger amounts of sediment delivered to the channels and as a result of the predicted increase in heavy precipitation events. At the same time, however, debris-flow volumes in high-mountain areas will depend chiefly on the stability and/or movement rates of permafrost bodies, and destabilized rock glaciers could lead to debris flows without historic precedents in the future. The frequency of rock slope failures is likely to increase, as excessively warm air temperatures, glacier shrinkage, as well as permafrost warming and thawing will affect and reduce rock slope stability in the direction that adversely affects rock slope stability. Changes in landslide activity in the French and Western Italian Alps will likely depend on differences in elevation. Above 1500 m asl, the projected decrease in snow season duration in future winters and springs will likely affect the frequency, number and seasonality of landslide reactivations. In Piemonte, for instance, 21st century landslides have been demonstrated to occur more frequently in early spring and to be triggered by moderate rainfalls, but also to occur in smaller numbers. On the contrary, and in line with recent observations, events in autumn, characterized by a large spatial density of landslide occurrences might become more scarce in the Piemonte region.

  13. Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments

    NASA Astrophysics Data System (ADS)

    Hilbe, Michael; Anselmetti, Flavio S.

    2015-02-01

    Previous studies of the sediments of Lake Lucerne have shown that massive subaqueous mass movements affecting unconsolidated sediments on lateral slopes are a common process in this lake, and, in view of historical reports describing damaging waves on the lake, it was suggested that tsunamis generated by mass movements represent a considerable natural hazard on the lakeshores. Newly performed numerical simulations combining two-dimensional, depth-averaged models for mass-movement propagation and for tsunami generation, propagation and inundation reproduce a number of reported tsunami effects. Four analysed mass-movement scenarios—three based on documented slope failures involving volumes of 5.5 to 20.8 × 106 m3—show peak wave heights of several metres and maximum runup of 6 to >10 m in the directly affected basins, while effects in neighbouring basins are less drastic. The tsunamis cause large-scale inundation over distances of several hundred metres on flat alluvial plains close to the mass-movement source areas. Basins at the ends of the lake experience regular water-level oscillations with characteristic periods of several minutes. The vulnerability of potentially affected areas has increased dramatically since the times of the damaging historical events, recommending a thorough evaluation of the hazard.

  14. Evolution of Mass Movements near Epicentre of Wenchuan Earthquake, the First Eight Years

    PubMed Central

    Zhang, Shuai; Zhang, Limin; Lacasse, Suzanne; Nadim, Farrokh

    2016-01-01

    It is increasingly clear that landslides represent a major cause of economic costs and deaths in earthquakes in mountains. In the Wenchuan earthquake case, post-seismic cascading landslides continue to represent a major problem eight years on. Failure to anticipate the impact of cascading landslides could lead to unexpected losses of human lives and properties. Previous studies tended to focus on separate landslide processes, with little attention paid to the quantification of long-term evolution of multiple processes or the evolution of mass movements. The very active mass movements near the epicentre of the Wenchuan earthquake provided us a unique opportunity to understand the complex processes of the evolving cascading landslides after a strong earthquake. This study budgets the mass movements on the hillslopes and in the channels in the first eight years since the Wenchuan earthquake and verify a conservation in mass movements. A system illustrating the evolution and interactions of mass movement after a strong earthquake is proposed. PMID:27824077

  15. The influence of mass movements on flow dynamics in carbonatic conglomerates in the Western Sattnitz, Carinthia (Austria)

    NASA Astrophysics Data System (ADS)

    Winkler, Gerfried; Thalheim, Felix

    2016-04-01

    The Turiawald plateau (about 6 km²) in the Western Sattnitz (Carinthia, Austria) is built up by massive carbonatic conglomerates with a thickness up to 200 m which are underlain by Miocene fine clastic sediments that act as an aquiclude and slightly incline towards NW. Nearly no overland flow occurs and most of the infiltrating water flows towards three captured major springs, the Roach spring, Pleier spring, and Hojoutz spring. Their catchments are characterized by highly differing in the occurrence of mass movements. The Roach spring drains about 75% of the plateau and is located in the west of the plateau and is influenced by a large-scale mass movement. The Pleier spring drains an area situated at the northern escarpment of the plateau influenced by smaller mass movements and rockfalls. The Hojoutz spring is supposed to be unaffected by mass movements as the water is collected in a gallery with a length of 110 m. This gallery was driven below the Turiawald plateau at the contact between the conglomerates and the aquiclude. Discharge (water level), water temperature and electrical conductivity data were continuously measured at these springs over a period of approximately three years. Additionally, air temperature and precipitation measurements are provided by a weather station located on top of the plateau. The recession analyses result three drainage components for each spring (first runoff, middle flow, and base flow). The Roach spring shows high discharge variability and the highest recession coefficients with a base flow coefficient of about 0.01 1/d. That is almost as high as the fast flow component of the other two springs. In addition, the discharge responses to groundwater recharge after several days. The water temperature seasonally ranges between 7.9 and 8.2 °C with a time shift of 4 to 6 months to the air temperature. The Pleier spring is characterized by a response to precipitation events after a few hours which can be extended up to nearly one

  16. Movement.

    ERIC Educational Resources Information Center

    Online-Offline, 1998

    1998-01-01

    Focuses on movement: movable art, relocating families, human rights, and trains and cars. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books, additional resources and activities (PEN)

  17. Ions in oceanic and continental air masses

    SciTech Connect

    Tanner, D.J.; Eisele, F.L. )

    1991-01-20

    Measurements of tropospheric ions and several trace atmospheric neutral species have been performed at Cheeka Peak Research Station and at Mauna Loa Observatory. Two new positive ion species at masses 114 and 102 have been identified as protonated caprolactam and a saturated 6-carbon primary amine, respectively. In the negative ion spectrum, methane sulfonic acid (MSA) has been identified as the parent species responsible for an ion commonly observed at mass 95 during these two studies. The diurnal variations of gas phase H{sub 2}SO{sub 4} and MSA were also measured at Cheeka Peak and have typically been found to be present in the sub-ppt range. Ion assisted measurements at Mauna Loa Observatory of pyridine and ammonia indicate concentrations of 2.5 and 70 ppt, respectively, with at least a factor of 2 uncertainty. Interesting variations and potential sources of several of the observed ions are also discussed.

  18. A data-based model to locate mass movements triggered by seismic events in Sichuan, China.

    PubMed

    de Souza, Fabio Teodoro

    2014-01-01

    Earthquakes affect the entire world and have catastrophic consequences. On May 12, 2008, an earthquake of magnitude 7.9 on the Richter scale occurred in the Wenchuan area of Sichuan province in China. This event, together with subsequent aftershocks, caused many avalanches, landslides, debris flows, collapses, and quake lakes and induced numerous unstable slopes. This work proposes a methodology that uses a data mining approach and geographic information systems to predict these mass movements based on their association with the main and aftershock epicenters, geologic faults, riverbeds, and topography. A dataset comprising 3,883 mass movements is analyzed, and some models to predict the location of these mass movements are developed. These predictive models could be used by the Chinese authorities as an important tool for identifying risk areas and rescuing survivors during similar events in the future.

  19. Mass Movement on Vesta at Steep Scarps and Crater Rims

    NASA Technical Reports Server (NTRS)

    Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.; De Sanctis, M. C.; Kneissl, T.; Schmedemann, N.; Kersten, E.; Stephan, K.; Matz, K.-D.; Pieters, C. M.; Preusker, F.; Roatsch, T.; Schenk, P.; Russell, C. T.; Raymond, C. A.

    2014-01-01

    The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.

  20. Some Problems of Movement of Bodies with Variable Masses and Cases of Their Integration

    NASA Astrophysics Data System (ADS)

    Mammadli, A. H.

    2009-12-01

    Problems of movement of bodies with variable masses within the framework of the two-body problem are considered. It is shown, that under certain conditions by the method of spatial-time transformation the differential equations of movement with variable coefficients suppose autonomization, i.e. are transformed to the differential equations with constant coefficients, integrated in quadrature. The analogue of the Jacobi integral is found, surfaces of zero velocity and possible regions of motion are determined. As an example the problem of the motion of a star with a variable mass inside a globular cluster with a variable mass is considered. It has turned out, that the solution of differential equations in new variables represents elliptical epicycloids, and in initial variables it is a very complex trajectory. At the research of motion in the gravitating and resisting medium it is shown, that in the law change of Jeans mass the change of a body mass sign is admissible.

  1. Total-reflection X-ray fluorescence — a tool to obtain information about different air masses and air pollution

    NASA Astrophysics Data System (ADS)

    Schmeling, Martina

    2001-11-01

    Atmospheric aerosols are solid particles dissolved in air and change their chemical composition frequently depending on various parameters. In order to identify regional air circulation atmospheric aerosol filter samples were taken at Loyola University Chicago's Lake Shore Campus during the months of July and August 2000 with sampling times ranging between 1 and 2 h. The samples were digested in a microwave oven and analyzed by total-reflection X-ray fluorescence (TXRF) spectrometry. One diurnal variation comprising five consecutive sampling events was selected and discussed as well as 4 days experiencing different meteorology were compared to exemplify the variation in trace elemental concentration according to air mass movements and highlight the capability of total-reflection X-ray fluorescence analysis. It was found that due to changes in meteorological conditions particularly wind direction and wind speed, trace elemental compositions varied rapidly and could be used to distinguish between 'Lake Michigan air' and 'metropolitan Chicago air' on such short-term time scale like one hour. Back trajectory analysis was applied to support and corroborate the results. The outcome of this study clearly shows that total-reflection X-ray fluorescence is an optimal tool for analysis of atmospheric aerosols.

  2. Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004 2006

    NASA Astrophysics Data System (ADS)

    Wehner, B.; Birmili, W.; Ditas, F.; Wu, Z.; Hu, M.; Liu, X.; Mao, J.; Sugimoto, N.; Wiedensohler, A.

    2008-10-01

    The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

  3. Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004-2006

    NASA Astrophysics Data System (ADS)

    Wehner, B.; Birmili, W.; Ditas, F.; Wu, Z.; Hu, M.; Liu, X.; Mao, J.; Sugimoto, N.; Wiedensohler, A.

    2008-06-01

    The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration (PM1 and PM10) by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

  4. Catastrophic mass movement of 1998 monsoons at Malpa in Kali Valley, Kumaun Himalaya (India)

    NASA Astrophysics Data System (ADS)

    Paul, S. K.; Bartarya, S. K.; Rautela, Piyoosh; Mahajan, A. K.

    2000-11-01

    A devastating landslide on 18 August 1998 near Malpa Village in Kali Valley of Higher Kumaun Himalaya killed 221 persons. The landslide was a complex rock fall-debris flow. The mass movement generated around one million cubic metres of debris and partially blocked the Kali River, Malpa Gad (a tributary of Kali) being blocked completely. The rock mass failed primarily due to the near vertical slopes hanging over the valley along joints, the formation of structural wedges along the free face, the sheared rock mass due to the close proximity of major tectonic planes, and the enhanced pore-water pressure due to prolonged heavy precipitation in the preceding days. The mesoscopic shear zone, exhibiting ramp and flat structure in quartzites, shows a southward thrust movement that might have generated shear stress in the rocks. The slide clearly demonstrates the distressed state of the rock mass in the Himalayan region due to the ongoing northward drift of the Indian plate.

  5. Mass MOVEMENTS' Detection in Hirise Images of the North Pole of Mars

    NASA Astrophysics Data System (ADS)

    Fanara, L.; Gwinner, K.; Hauber, E.; Oberst, J.

    2016-06-01

    We are investigating change detection techniques to automatically detect mass movements at the steep north polar scarps of Mars, in order to improve our understanding of these dynamic processes. Here we focus on movements of blocks specifically. The precise detection of such small changes requires an accurate co-registration of the images, which is achieved by ortho-rectifying them using High Resolution Imaging Science Experiment (HiRISE) Digital Terrain Models (DTMs). Moreover, we deal with the challenge of deriving the true shape of the moved blocks. In a next step, these results are combined with findings based on HiRISE DTMs from different points in time in order to estimate the volume of mass movements.

  6. Revisiting submarine mass movements along the U.S. Atlantic Continental Margin: implications for tsunami hazards

    USGS Publications Warehouse

    Chaytor, J.D.; Twichell, D.C.; ten Brink, U.S.; Buczkowski, B.J.; Andrews, B.D.

    2007-01-01

    Interest in the generation of tsunamis by submarine mass movements has warranted a reassessment of their distribution and the nature of submarine landslides offshore of the eastern U.S. The recent acquisition and analysis of multibeam bathymetric data over most of this continental slope and rise provides clearer view into the extent and style of mass movements on this margin. Debris flows appear to be the dominant type of mass movement, although some translational slides have also been identified. Areas affected by mass movements range in size from less than 9 km2 to greater than 15,200 km2 and reach measured thicknesses of up to 70 m. Failures are seen to originate on either the open-slope or in submarine canyons. Slope-sourced failures are larger than canyonsourced failures, suggesting they have a higher potential for tsunami generation although the volume of material displaced during individual failure events still needs to be refined. The slope-sourced failures are most common offshore of the northern, glaciated part of the coast, but others are found downslope of shelf-edge deltas and near salt diapirs, suggesting that several geological conditions control their distribution.

  7. Mass-movement deposits in the lacustrine Eocene Green River Formation, Piceance Basin, western Colorado

    USGS Publications Warehouse

    Johnson, Ronald C.; Birdwell, Justin E.; Brownfield, Michael E.; Mercier, Tracey J.

    2015-01-01

    The Eocene Green River Formation was deposited in two large Eocene saline lakes, Lake Uinta in the Uinta and Piceance Basins and Lake Gosiute in the Greater Green River Basin. Here we will discuss mass-movement deposits in just the Piceance Basin part of Lake Uinta.

  8. Using the Earth as a guide to martian mass movement processes: From form to process

    NASA Astrophysics Data System (ADS)

    Lanza, N.; Newsom, H. E.; Osterloo, M. M.; Okubo, C. H.

    2011-12-01

    The discovery of gully features on Mars has led to renewed interest in hillslope processes on that planet, in particular mass movement and the morphologies that it produces. Mass movement is a collection of gravity-driven processes that act to move materials down a hillslope. Here, we examine how mass movements on hillslopes may be expected to differ on Earth and Mars as the result of gravity differences between these planets. Downslope movement of unconsolidated materials is generally controlled by the bulk shear strength of these materials. Although the relationship between gravity and shear strength is largely dependent on variables that are independent of gravity, the lower gravity on Mars is expected to produce some systematic changes in mass movement behaviors that may in turn create morphological features that are observably different from their terrestrial counterparts. After scaling for gravity and modifying empirically derived relationships, we may expect the following differences on martian hillslopes when compared to their terrestrial counterparts: ==On Mars, hillslopes may have steeper angles of repose in fine grained (< ~2 mm) materials, even when dry. No change in angle of repose is expected for larger particles; ==An increase in soil moisture content (e.g., excess pore pressure) is expected to weaken unconsolidated slope materials more on Mars for a particular regolith type, which in turn may produce --An increase in creep rates for a given pore pressure, and --An increase in effectiveness of frost heave to transport materials downslope; ==Processes triggered by saturation may occur at lower pore pressures on Mars; --A smaller amount of fluid is needed to achieve failure; ==Shorter runout lengths are expected for rapid mass movements; ==On Mars, overland flow will exert a proportionally lower shear stress on slope materials; --In cohesive materials, the same volume of water will detach sediments of smaller sizes. On Earth, mass movement processes

  9. Where do the air masses between double tropopauses come from?

    NASA Astrophysics Data System (ADS)

    Parracho, A. C.; Marques, C. A. F.; Castanheira, J. M.

    2014-01-01

    An analysis of the origin of air masses that end up between double tropopauses (DT) in the subtropics and midlatitudes is presented. The double tropopauses were diagnosed in the ERA-Interim reanalysis (1979-2010), and the origin of air masses was analysed using the Lagrangian model FLEXPART. Different processes for the formation of double tropopauses (DT) have been suggested in the literature. Some studies have suggested that double tropopauses may occur as a response to the vertical profile of adiabatic heating, due to the residual meridional circulation, while others have put forward contradicting explanations. Whereas some studies have suggested that double tropopauses result from poleward excursions of the tropical tropopause over the extratropical one, others have argued that DTs develop in baroclinic unstable processes involving transport of air from high latitudes. In some regions, the DT structure has a semipermanent character which cannot be explained by excursions of the tropical tropopause alone. However, the results presented in this paper confirm that processes involving excursions of the tropical tropopause over the extratropical tropopause, which are therefore accompanied by intrusions of air from the tropical troposphere into the lower extratropical stratosphere, make a significant contribution for the occurrence of DTs in the subtropics and midlatitudes. Specifically, it is shown that the air between double tropopauses comes from equatorward regions, and has a higher percentage of tropospheric particles and a lower mean potential vorticity.

  10. "Quien Sabe Mas Lucha Mejor": Adult Educators' Care of the Self Practices within Social Movements in Buenos Aires, Argentina

    ERIC Educational Resources Information Center

    O'Donnell, Jennifer Lee

    2014-01-01

    This article looks at popular adult educators' care of the self practices within social movements in Buenos Aires, Argentina. It answers the following questions: How is popular adult education practiced amongst educators in social movements? What can studying popular adult educators' care of the self practices offer the field of adult education?…

  11. Mass Movement and Landform Degradation on the Icy Galilean Satellites: Results of the Galileo Nominal Mission

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.; Asphaug, Erik; Morrison, David; Spencer, John R.; Chapman, Clark R.; Bierhaus, Beau; Sullivan, Robert J.; Chuang, Frank C.; Klemaszewski, James E.; Greeley, Ronald

    1999-01-01

    The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on the icy Galilean satellites of Jupiter. Weakening of surface materials coupled with mass movement reduces the topographic relief of landforms by moving surface materials down-slope. Throughout the Galileo orbiter nominal mission we have studied all known forms of mass movement and landform degradation of the icy galilean satellites, of which Callisto, by far, displays the most degraded surface. Callisto exhibits discrete mass movements that are larger and apparently more common than seen elsewhere. Most degradation on Ganymede appears consistent with sliding or slumping, impact erosion, and regolith evolution. Sliding or slumping is also observed at very small (100 m) scale on Europa. Sputter ablation, while probably playing some role in the evolution of Ganymede's and Callisto's debris layers, appears to be less important than other processes. Sputter ablation might play a significant role on Europa only if that satellite's surface is significantly older than 10(exp 8) years, far older than crater statistics indicate. Impact erosion and regolith formation on Europa are probably minimal, as implied by the low density of small craters there. Impact erosion and regolith formation may be important on the dark terrains of Ganymede, though some surfaces on this satellite may be modified by sublimation-degradation. While impact erosion and regolith formation are expected to operate with the same vigor on Callisto as on Ganymede, most of the areas examined at high resolution on Callisto have an appearance that implies that some additional process is at work, most likely sublimation-driven landform modification and mass wasting. The extent of surface degradation ascribed to sublimation on the outer two Galilean satellites implies that an ice more volatile than H2O is probably involved.

  12. Mass movements and tree rings: A guide to dendrogeomorphic field sampling and dating

    NASA Astrophysics Data System (ADS)

    Stoffel, Markus; Butler, David R.; Corona, Christophe

    2013-10-01

    Trees affected by mass movements record the evidence of geomorphic disturbance in the growth-ring series, and thereby provide a precise geochronological tool for the reconstruction of past activity of mass movement. The identification of past activity of processes was typically based on the presence of growth anomalies in affected trees and focused on the presence of scars, tilted or buried trunks, as well as on apex decapitation. For the analyses and interpretation of disturbances in tree-ring records, in contrast, clear guidelines have not been established, with largely differing or no thresholds used to distinguish signal from noise. At the same time, processes with a large spatial footprint (e.g., snow avalanches, landslides, or floods) will likely leave growth anomalies in a large number of trees, whereas a falling rock would only cause scars in one or a few trees along its trajectory.

  13. Assessment Of Slope Covers Vulnerability To Shallow Mass Movements Using Sinmap

    NASA Astrophysics Data System (ADS)

    Demczuk, Piotr; Zydroń, Tymoteusz; Franczak, Łukasz

    2014-06-01

    In Flysch Carpathians mass movements are a significant factor that causes changes in the morphology of slopes and, in many cases, causes also economic damage. A complicated geological structure of the area, high height differences and high rainfall, which is the main factor initiating mass movements, are mainly listed among the basic conditions for such type of processes to occur. Infiltration of rainfall in the soil profile can lead to a loss of stability in two ways (Crosta 1998). Infiltration process can cause an increase in the groundwater level when there are low intensity rainfalls. High intensity rainfalls can cause creating of perched water table in the area of moving quench front, therefore in many publications in the field of geotechnics and engineering geology (among others: Crosta 1998; Li et al. 2006; Rahardjo et al. 2007, 2010; Tu et al. 2009) assessment of vulnerability of slope covers to mass movements does not focus only on the strength parameters of the soil, but it also takes infiltration of rainfall into consideration. Because of a recent development of spatial information systems, slope stability evaluation is more often done in relation to large areas, comprising river basins or even regions (Montgomery and Dietrich 1994; Morrissey et al. 2001; Meisina and Scarabelli 2007). One of the generally used in GIS environment phy sical model of water distribution in the soil profile that allows to determine slope stability is SINMAP (Pack et al. 1999). An attempt to do a preliminary assessment of vulnerability of surface slope covers from the area of Nowy Wiśnicz commune to mass movements using SINMAP model was made and presented in the paper, along with the verification of modeling results with actual existing landslides

  14. Mass Movement Susceptibility in the Western San Juan Mountains, Colorado: A Preliminary 3-D Mapping Approach

    NASA Astrophysics Data System (ADS)

    Kelkar, K. A.; Giardino, J. R.

    2015-12-01

    Mass movement is a major activity that impacts lives of humans and their infrastructure. Human activity in steep, mountainous regions is especially at risk to this potential hazard. Thus, the identification and quantification of risk by mapping and determining mass movement susceptibility are fundamental in protecting lives, resources and ensuring proper land use regulation and planning. Specific mass-movement processes including debris flows, rock falls, snow avalanches and landslides continuously modify the landscape of the San Juan Mountains. Historically, large-magnitude slope failures have repeatedly occurred in the region. Common triggers include intense, long-duration precipitation, freeze-thaw processes, human activity and various volcanic lithologies overlying weaker sedimentary formations. Predicting mass movement is challenging because of its episodic and spatially, discontinuous occurrence. Landslides in mountain terrain are characterized as widespread, highly mobile and have a long duration of activity. We developed a 3-D model for landslide susceptibility using Geographic Information Systems Technology (GIST). The study area encompasses eight USGS quadrangles: Ridgway, Dallas, Mount Sneffels, Ouray, Telluride, Ironton, Ophir and Silverton. Fieldwork consisted of field reconnaissance mapping at 1:5,000 focusing on surficial geomorphology. Field mapping was used to identify potential locations, which then received additional onsite investigation and photographic documentation of features indicative of slope failure. A GIS module was created using seven terrain spatial databases: geology, surficial geomorphology (digitized), slope aspect, slope angle, vegetation, soils and distance to infrastructure to map risk. The GIS database will help determine risk zonation for the study area. Correlations between terrain parameters leading to slope failure were determined through the GIS module. This 3-D model will provide a spatial perspective of the landscape to

  15. Writing in the Air: Contributions of Finger Movement to Cognitive Processing.

    PubMed

    Itaguchi, Yoshihiro; Yamada, Chiharu; Fukuzawa, Kazuyoshi

    2015-01-01

    The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is called kusho, meaning air-writing in Japanese. However, its functional role is still unknown. To reveal the role of kusho behavior in cognitive processing, we conducted a series of experiments, employing two different cognitive tasks, a construction task and a stroke count task. To distinguish the effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks; participants were instructed to use either kusho, unrelated finger movements or do nothing during the response time. To isolate possible visual effects, two visual conditions in which participants saw their hand and the other in which they did not, were introduced. We used the number of correct responses and response time as measures of the task performance. The results showed that kusho behavior has different functional roles in the two types of cognitive tasks. In the construction task, the visual feedback from finger movement facilitated identifying a character, whereas the kinetic feedback or motor commands for the behavior did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of the finger movements influenced counting performance depending on the type of the finger movement. Regardless of the visual condition, kusho behavior improved task performance and unrelated finger movements degraded it. These results indicated that motor behavior contributes to cognitive processes. We discussed possible mechanisms of the modality dependent contribution. These findings might lead to better understanding of the complex interaction between action and cognition in daily life.

  16. Writing in the Air: Contributions of Finger Movement to Cognitive Processing

    PubMed Central

    Itaguchi, Yoshihiro; Yamada, Chiharu; Fukuzawa, Kazuyoshi

    2015-01-01

    The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is called kusho, meaning air-writing in Japanese. However, its functional role is still unknown. To reveal the role of kusho behavior in cognitive processing, we conducted a series of experiments, employing two different cognitive tasks, a construction task and a stroke count task. To distinguish the effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks; participants were instructed to use either kusho, unrelated finger movements or do nothing during the response time. To isolate possible visual effects, two visual conditions in which participants saw their hand and the other in which they did not, were introduced. We used the number of correct responses and response time as measures of the task performance. The results showed that kusho behavior has different functional roles in the two types of cognitive tasks. In the construction task, the visual feedback from finger movement facilitated identifying a character, whereas the kinetic feedback or motor commands for the behavior did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of the finger movements influenced counting performance depending on the type of the finger movement. Regardless of the visual condition, kusho behavior improved task performance and unrelated finger movements degraded it. These results indicated that motor behavior contributes to cognitive processes. We discussed possible mechanisms of the modality dependent contribution. These findings might lead to better understanding of the complex interaction between action and cognition in daily life. PMID:26061273

  17. 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.

  18. 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.

  19. Dynamics of a complex mass movement triggered by heavy rainfall: a case study from NW Turkey

    NASA Astrophysics Data System (ADS)

    Ocakoglu, Faruk; Gokceoglu, Candan; Ercanoglu, Murat

    2002-01-01

    Following a period of heavy precipitation, a large and complex mass movement, namely the Dagkoy landslide, occurred in the West Black Sea Region of Turkey on May 21, 1998. This paper describes the conditioning factors of the landslide and interprets the mass transport processes in terms of a movement scenario. Geology, geomorphology and vegetation cover were considered as the conditioning factors of the failure. Observations showed that the gently sloping (about 10°) area is mostly covered by dense forest trees at the crown where the motion initiated. Significant intersection of the collapsed slope with dip of the local marls seems to have contributed to the formation and geometry of the landslide. The distance from the crown down to the toe of the landslide measured more than 600 m, with about 0.6 km 3 total earth material displaced. The landslide has both a block sliding characteristics in the upper portions and a debris flow/soil flow component around the margins of the sliding blocks in the middle parts and at the toe. The proposed scenario for the landslide reveals that the movement was initiated near crown as a result of the excess water content in the marls at the end of 3 days of heavy rainfall. The early perturbations (transverse cracks, ridges, etc.) lasted for 6-7 h, after which the central part of the zone started to move as a soil flow in which very large intact blocks were transported. Even though the movement was very rapid (1.2 m/min), there was no loss of life. However, the movement destroyed 38 houses, one mosque and a considerable amount of farmland.

  20. Frequency, triggering factors and possible consequences of mass movements on outlet glaciers in Iceland.

    NASA Astrophysics Data System (ADS)

    Saemundsson, Thorsteinn; Margeirsson, Guðbjörn

    2016-04-01

    During the last 15 years several mass movements of various size and origin, e.g. rock avalanches, rock slides and debris slides have been observed to have fall on outlet glaciers in Iceland. This should not come as a surprise in this type of glacial environment, but in a way it does. When looking at the history only few mass movements are recorded to have fall on outlet glaciers in Iceland, during the decades before the year 2000 or since 1960. This "lack of mass movements" can be explained by the fact that fewer observations and monitoring were done in the past, but is it so or are we seeing increasing activity? Looking at the distribution of the known mass movements, two activity periods cam be identified. The former one around 1970 and the second one starting around 2000 and is still ongoing. Both of these periods are characterized by warmer climate leading to retreating phases of glaciers. Two larger mass movements are known from these two retreating periods. The former one occurred in January 1967. Then a large rockslide fell on the snout and into the glacial lake of the Steinholtsjökull outlet glacier in the northern side of the Eyjafjallajökull ice cap. The rockslide broke up the snout of the glacier and caused large floodwave bursting down the Steinholtsdalur valley transporting large volume of sediments down its path. The later one occurred in 2007, when a large rockavalanche fell on the Morsárjökull outlet glacier, in the southern side of the Vatnajökull ice cap. The avalanche debris covered around 1/5 of the glacier surface. Today the retreat and thinning of glaciers in Iceland are extremely rapid. The consequences of such a rapid retreat are e.g. unstable valley slopes surrounding the outlet glaciers, both in loose sediments and bedrock, thawing of mountain permafrost and not least formation of glacial lakes in front of the rapid retreating ice margins. Such conditions can become extremely hazardous, as seen by the above mentioned examples, both

  1. Assessment of advective porewater movement affecting mass transfer of hydrophobic organic contaminants in marine intertidal sediment.

    PubMed

    Cho, Yeo-Myoung; Werner, David; Moffett, Kevan B; Luthy, Richard G

    2010-08-01

    Advective porewater movement and molecular diffusion are important factors affecting the mass transfer of hydrophobic organic compounds (HOCs) in marsh and mudflat sediments. This study assessed porewater movement in an intertidal mudflat in South Basin adjacent to Hunters Point Shipyard, San Francisco, CA, where a pilot-scale test of sorbent amendment assessed the in situ stabilization of polychlorinated biphenyls (PCBs). To quantify advective porewater movement within the top 0-60 cm sediment layer, we used temperature as a tracer and conducted heat transport analysis using 14-day data from multidepth sediment temperature logging stations and one-dimensional heat transport simulations. The best-fit conditions gave an average Darcy velocity of 3.8cm/d in the downward vertical direction for sorbent-amended sediment with a plausible range of 0 cm/d to 8 cm/d. In a limiting case with no net advection, the best-fit depth-averaged mechanical dispersion coefficient was 2.2x10(-7) m2/s with a range of 0.9x10(-7) m2/s to 5.6x10(-7) m2/s. The Peclet number for PCB mobilization showed that molecular diffusion would control PCB mass transfer from sediment to sorbent particles for the case of uniform distribution of sorbent. However, the advective flow and mechanical dispersion in the test site would significantly benefit the stabilization effect of heterogeneously distributed sorbent by acting to smooth out the heterogeneities and homogenizing pollutant concentrations across the entire bioactive zone. These measurements and modeling techniques on intertidal sediment porewater transport could be useful for the development of more reliable mass transfer models for the prediction of contaminant release within the sediment bed, the movement of HOCs in the intertidal aquatic environment, and in situ sequestration by sorbent addition.

  2. Parameterization experiments performed via synthetic mass movements prototypes generated by 3D slope stability simulator

    NASA Astrophysics Data System (ADS)

    Colangelo, Antonio C.

    2010-05-01

    The central purpose of this work is to perform a reverse procedure in the mass movement conventional parameterization approach. The idea is to generate a number of synthetic mass movements by means of the "slope stability simulator" (Colangelo, 2007), and compeer their morphological and physical properties with "real" conditions of effective mass movements. This device is an integrated part of "relief unity emulator" (rue), that permits generate synthetic mass movements in a synthetic slope environment. The "rue" was build upon fundamental geomorphological concepts. These devices operate with an integrated set of mechanical, geomorphic and hydrological models. The "slope stability simulator" device (sss) permits to perform a detailed slope stability analysis in a theoretical three dimensional space, by means of evaluation the spatial behavior of critical depths, gradients and saturation levels in the "potential rupture surfaces" inferred along a set of slope profiles, that compounds a synthetic slope unity. It's a meta-stable 4-dimensional object generated by means of "rue", that represents a sequence evolution of a generator profile applied here, was adapted the infinite slope model for slope. Any slope profiles were sliced by means of finite element solution like in Bishop method. For the synthetic slope systems generated, we assume that the potential rupture surface occurs at soil-regolith or soil-rock boundary in slope material. Sixteen variables were included in the "rue-sss" device that operates in an integrated manner. For each cell, the factor of safety was calculated considering the value of shear strength (cohesion and friction) of material, soil-regolith boundary depth, soil moisture level content, potential rupture surface gradient, slope surface gradient, top of subsurface flow gradient, apparent soil bulk density and vegetation surcharge. The slope soil was considered as cohesive material. The 16 variables incorporated in the models were analyzed for

  3. Elevated air movement enhances stomatal sensitivity to abscisic acid in leaves developed at high relative air humidity

    PubMed Central

    Carvalho, Dália R. A.; Torre, Sissel; Kraniotis, Dimitrios; Almeida, Domingos P. F.; Heuvelink, Ep; Carvalho, Susana M. P.

    2015-01-01

    High relative air humidity (RH ≥ 85%) during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV) 24 h per day, during the whole period of leaf development would increase abscisic acid concentration ([ABA]) enhancing stomatal functioning. Pot rose ‘Toril’ was grown at moderate (61%) or high (92%) RH combined with a continuous low (0.08 m s-1) or high (0.92 m s-1) MOV. High MOV reduced stomatal pore length and aperture in plants developed at high RH. Moreover, stomatal function improved when high MOV-treated plants were subjected to leaflet desiccation and ABA feeding. Endogenous concentration of ABA and its metabolites in the leaves was reduced by 35% in high RH, but contrary to our hypothesis this concentration was not significantly affected by high MOV. Interestingly, in detached leaflets grown at high RH, high MOV increased stomatal sensitivity to ABA since the amount of exogenous ABA required to decrease the transpiration rate was significantly reduced. This is the first study to show that high MOV increases stomatal functionality in leaves developed at high RH by reducing the stomatal pore length and aperture and enhancing stomatal sensitivity to ABA rather than increasing leaf [ABA]. PMID:26074943

  4. Unravelling the multiphase run-out conditions of a slide-flow mass movement

    NASA Astrophysics Data System (ADS)

    van Asch, Th. W. J.; Xu, Q.; Dong, X. J.

    2015-02-01

    In this paper an attempt is made to unravel the run-out characteristics of a mass movement in the Sichuan Province, SW China by means of 1D numerical modelling and calibration on the topography of run-out profiles. The Dagou mass movement started as a rockslide with an initial volume of 480,000 m3, which transformed into a debris flow, increasing in volume due to entrainment of loose material in the upper part of the travelling track. The rapid mass movement had a run-out distance of 1380 m and a run-out time of about 50 s. Numerical calculations were conducted with the depth average shallow water equation to explain the variation in thickness of the debris flow deposits along the run-out track. For the calibration of the first run-out phase, three rheological models were applied, namely the Bingham, Voellmy and Quadratic rheology. Calibration was done on 1) the run-out distance, 2) the run-out time and 3) the goodness of fit with the thickness of the deposits along the track. In addition the erosion constant in the entrainment equation was calibrated on the observed versus calculated run-out volumes. Sensitivity analyses of the resistance parameters for the different rheologies showed that the viscosity, the basal friction, the turbulence term and the resistance factor are the most sensitive ones. It appeared that the variation in thickness along the run-out track can be explained by entrainment of material in the upper part of the track and a change in parametric values during the run-out process. The three rheologies produced a reasonable fit with the observed geometry of the run-out profile, run-out time and run-out volume. It was argued that the Voellmy rheology seems to give the most appropriate explanation for the difference in resistance along the run-out path. The main problem in the simulation was to stop the debris flow on a slope with a gradient around 22°. A reactivation of the mass movement by frictional sliding of the material half way the run

  5. r.randomwalk v1, a multi-functional conceptual tool for mass movement routing

    NASA Astrophysics Data System (ADS)

    Mergili, M.; Krenn, J.; Chu, H.-J.

    2015-12-01

    We introduce r.randomwalk, a flexible and multi-functional open-source tool for backward and forward analyses of mass movement propagation. r.randomwalk builds on GRASS GIS (Geographic Resources Analysis Support System - Geographic Information System), the R software for statistical computing and the programming languages Python and C. Using constrained random walks, mass points are routed from defined release pixels of one to many mass movements through a digital elevation model until a defined break criterion is reached. Compared to existing tools, the major innovative features of r.randomwalk are (i) multiple break criteria can be combined to compute an impact indicator score; (ii) the uncertainties of break criteria can be included by performing multiple parallel computations with randomized parameter sets, resulting in an impact indicator index in the range 0-1; (iii) built-in functions for validation and visualization of the results are provided; (iv) observed landslides can be back analysed to derive the density distribution of the observed angles of reach. This distribution can be employed to compute impact probabilities for each pixel. Further, impact indicator scores and probabilities can be combined with release indicator scores or probabilities, and with exposure indicator scores. We demonstrate the key functionalities of r.randomwalk for (i) a single event, the Acheron rock avalanche in New Zealand; (ii) landslides in a 61.5 km2 study area in the Kao Ping Watershed, Taiwan; and (iii) lake outburst floods in a 2106 km2 area in the Gunt Valley, Tajikistan.

  6. Puzzling mass movement features in the Navarinsky Canyon head, Bering Sea

    USGS Publications Warehouse

    Carlson, P.R.; Karl, Herman A.; Edwards, B.D.

    1982-01-01

    Two types of morphologic features in the head of Navarinsky Canyon are attributed to mass movement of near-surface sediment. A series of pull-aparts is located downslope of large sand waves. These pull-aparts, possibly induced by liquefaction, affect the upper 5 to 10 m of sandy sediment (water depths 350 to 600 m) on a 1o slope. A hummocky elongate mound of muddy sand (water depths 550 to 800 m) contains chaotic internal reflectors to a subbottom depth of 30 to 40 m and possibly is the product of a shallow slide. We speculate that Holocene seismicity is the likely triggering mechanism. ?? 1982 A. M. Dowden, Inc.

  7. Mapping mass movement processes using terrestrial LIDAR: a swift mechanism for hazard and disaster risk assessment

    NASA Astrophysics Data System (ADS)

    Garnica-Peña, Ricardo; Murillo-García, Franny; Alcántara-Ayala, Irasema

    2014-05-01

    The impact of disasters associated with mass movement processes has increased in the past decades. Either triggered by earthquakes, volcanic activity or rainfall, mass movement processes have affected people, infrastructure, economic activities and the environment in different parts of the world. Extensive damage is particularly linked to rainfall induced landslides due to the occurrence of tropical storms, hurricanes, and the combination of different meteorological phenomenon on exposed vulnerable communities. Therefore, landslide susceptibility analysis, hazard and risk assessments are considered as significant mechanisms to lessen the impact of disasters. Ideally, these procedures ought to be carried out before disasters take place. However, under intense or persistent periods of rainfall, the evaluation of potentially unstable slopes becomes a critical issue. Such evaluations are constrained by the availability of resources, capabilities and scientific and technological tools. Among them, remote sensing has proved to be a valuable tool to evaluate areas affected by mass movement processes during the post-disaster stage. Nonetheless, the high cost of imagery acquisition inhibits their wide use. High resolution topography field surveys consequently, turn out to be an essential approach to address landslide evaluation needs. In this work, we present the evaluation and mapping of a series of mass movement processes induced by hurricane Ingrid in September, 2013, in Teziutlán, Puebla, México, a municipality situated 265 km Northeast of Mexico City. Geologically, Teziutlán is characterised by the presence, in the North, of siltstones and conglomerates of the Middle Jurassic, whereas the central and Southern sectors consist of volcanic deposits of various types: andesitic tuffs of Tertiary age, and basalts, rhyolitic tuffs and ignimbrites from the Quaternary. Major relief structures are formed by the accumulation of volcanic material; lava domes, partially buried

  8. Rock glaciers originating from mass movements: A new model based on field data

    NASA Astrophysics Data System (ADS)

    Reitner, J. M.; Gruber, A.

    2009-04-01

    The morphological and geological conditions for the formation of rock glaciers in Alpine environments seem to be clear according to our present knowledge (BARSCH, 1996; HAEBERLI et al. 2006). All known examples derive from porous more or less coarse grained sedimentary bodies, either from moraines or, in most cases, from talus fans. In the latter case the debris accumulation originates overwhelmingly from physical weathering, rock falls or rock avalanches in proximity to rockwalls. However, in the course of geological mapping in the crystalline areas of Eastern and Northern Tyrol (Schober Gruppe, Tuxer Alpen) we found an additional setting. Some relict rock glaciers occur directly at the bulging toe of bedrock slopes, which had been affected by deep-seated gravitational slope deformations (REITNER, 2003; GRUBER, 2005). Furthermore rock glaciers are also present in ridge-top depressions and similar graben-like features that originated from gravitational processes in jointed bedrock. In all these cases talus fans with debris accumulation are missing in the source area of those rock glaciers. According to our model the disintegration of jointed rocks by creeping mass movements resulted in an increased volume of joint space. This enabled the formation of interstitial ice under permafrost conditions. Increased ice saturation led to the reduction of the angle of internal friction and finally to the initial formation of a rock glacier. Abundant material was provided for the further movement and thus for formation of quite large rock glaciers due to the previous and maybe still ongoing slope deformation. Most rock glaciers of this type originated from mass movements of sagging -type (Sackung sensu ZISCHINSKY, 1966), which illustrates the continuous transition from gravitational to periglacial creep process in high Alpine areas. All studied examples are of Lateglacial age according to the altitude in correspondence to the known amount of permafrost depression compared to

  9. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

    NASA Astrophysics Data System (ADS)

    Dugaria, S.; Moro, L.; Del, D., Col

    2015-11-01

    The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

  10. Micromorphology in unconsolidated landslide sediments - investigating mass movement deposits at a different scale

    NASA Astrophysics Data System (ADS)

    Jaeger, Daniel; Menzies, John

    2015-04-01

    In order to reliably reconstruct a landslide event, its triggers, movements and the main factors of influence, a profound knowledge of the slide masses' inner architecture and their internal processes is of great importance. As van der Meer (1996) states, micromorphology permits a complete examination of particles, matrix and all components contained in unconsolidated sediments, as well as an insight into their internal arrangement. So far, thin sections and micromorphology are mainly used for studying marine, periglacial and glacial sediments (e.g. Maltman 1988; van der Meer 1993, Menzies 2000, van Fliet-Lanoe 2010, van der Meer & Menzies 2011). Comparatively little work has been carried out with a focus on landslides (e.g. Bertran & Texier 1999). Therefore, our work is a first attempt at investigating unconsolidated deposits of landslides in the low mountain areas of southern Germany using micromorphological tools. The objective was to observe sedimentary microstructures in order to gain an understanding of the sediments' internal movement, deformation etc. during a slide event. On the investigated landslides near Ebermannstadt (Franconian Alb), Gailnau (Frankenhöhe region) and Talheim (Swabian Alb) samples were taken from small pits or outcrops (depths between 50 cm - 300 cm below the surface) in the upper, central and lower part (foot) of the slide mass. The thin section analyses revealed several differences between the three environments and within the specific landslides themselves. Most prominently, several structures (e.g. water-escape-structures, flow-noses and rotational structures) indicate a crucial impact of water in all three slide masses. Furthermore, the thin sections showed heterogeneous compositions of different sediment materials and aggregates, presumably transported, mixed together and deformed during the slide movement. In Ebermannstadt and Talheim, several ductile and brittle deformation structures (rotational structures, marbled structures

  11. Lacustrine chronology links late Pleistocene climate change and mass movements in northern New Mexico

    SciTech Connect

    Dethier, D.P.; Reneau, S.L.

    1996-06-01

    Well-dated lacustrine deposits in northern White Rock Canyon, New Mexico, record damming of the Rio Grande by at least four separate failures of a slump complex between about 17.5 and 12.4 ka ({sup 14}C), linking mass movements to a period of rapid climate change in the western United States. Failure of metastable slumps probably resulted from removal of lateral support during down-cutting and erosion by the Rio Grande and from a decrease in resisting forces due to increased pore pressures. Our chronology suggests that the lake that formed between 17.5 and 15.0 ka may record effects of both glacial melt and pluvial activity (mainly enhanced rainfall); the youngest lake (neary 12.4 ka) may record pluvial runoff; and the intermediate lakes (13.7 to 13.1 ka) may record pluvial and minor melt-water activity. We have not found lacustrine deposits younger than about 12.4 ka. The record of geomorphic response along the Rio Grande suggests that late Pleistocene climatic changes may have triggered similar mass movements elsewhere in the southwest. 27 refs., 4 figs.

  12. Modelling rapid mass movements using the shallow water equations in Cartesian coordinates

    NASA Astrophysics Data System (ADS)

    Hergarten, S.; Robl, J.

    2015-03-01

    We propose a new method to model rapid mass movements on complex topography using the shallow water equations in Cartesian coordinates. These equations are the widely used standard approximation for the flow of water in rivers and shallow lakes, but the main prerequisite for their application - an almost horizontal fluid table - is in general not satisfied for avalanches and debris flows in steep terrain. Therefore, we have developed appropriate correction terms for large topographic gradients. In this study we present the mathematical formulation of these correction terms and their implementation in the open-source flow solver GERRIS. This novel approach is evaluated by simulating avalanches on synthetic and finally natural topographies and the widely used Voellmy flow resistance law. Testing the results against analytical solutions and the proprietary avalanche model RAMMS, we found a very good agreement. As the GERRIS flow solver is freely available and open source, it can be easily extended by additional fluid models or source areas, making this model suitable for simulating several types of rapid mass movements. It therefore provides a valuable tool for assisting regional-scale natural hazard studies.

  13. Potential tsunamigenic hazard associated to submarine mass movement along the Ionian continental margin (Mediterranean Sea).

    NASA Astrophysics Data System (ADS)

    Ceramicola, S.; Tinti, S.; Praeg, D.; Zaniboni, F.; Planinsek, P.

    2012-04-01

    Submarine mass movements are natural geomorphic processes that transport marine sediment down continental slopes into deep-marine environments. Type of mass wasting include creep, slides, slump, debris flows, each with its own features and taking place over timescale from seconds to years. Submarine landslides can be triggered by a number of different causes, either internal (such as changes in physical chemical sediment properties) or external (e.g. earthquakes, volcanic activity, salt movements, sea level changes etc.). Landslides may mobilize sediments in such a way as to form an impulsive vertical displacement of a body of water, originating a wave or series of waves with long wavelengths and long periods called tsunamis ('harbor waves'). Over 600 km of continental margin has been investigated by OGS in the Ionian sea using geophysical data - morpho-bathymetry (Reson 8111, 8150) and sub-bottom profiles (7-10 KHz) - collected aboard the research vessel OGS Explora in the framework of the MAGIC Project (Marine Geohazard along the Italian Coasts), funded by the Italian Civil Protection. The objective of this project is the definition of elements that may constitute geological risk for coastal areas. Geophysical data allowed the recognition of four main types of mass wasting phenomena along the slopes of the ICM: 1) mass transport complexes (MTCs) within intra-slope basins. Seabed imagery show the slopes of all the seabed ridges to be marked by headwall scarps recording widespread failure, multiple debris flows in several basins indicate one or more past episodes of failure that may be linked to activity on the faults bounding the structural highs. 2) submarine landslide - a multiple failure event have been identified (Assi landslide) at about 6 km away from the coastline nearby Riace Marina. Headwall scars up to 50 m high across water depths of 700 to 1400 m, while sub-bottom profiles indicate stacked slide deposits at and near seabed. 4) canyon headwalls - in the

  14. 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.

  15. Large mass movements related to deglaciation effects in southern Peru (Cusco)

    NASA Astrophysics Data System (ADS)

    Giráldez, Claudia; Choquevilca, Walter; Fernández, Felipe; Frey, Holger; García, Javier; Haeberli, Wilfried; Huggel, Christian; Ludena, Sebastián; Rohrer, Mario; Suarez, Wilson

    2013-04-01

    The Andes of Peru are among the regions most severely affected by glacier and high-mountain hazards over the past 100 years. Large-scale disasters with thousands of people killed are on record, including ice/rock avalanches, debris flows, and glacier lake outburst floods (GLOF's). Effects of climate change such as glacier retreat and formation of glacier lakes have been one of the drivers of hazards in the past. Now, there is an increasing concern about the destabilizing effect that recent and further warming has a on perennially frozen bedrock and on steep glaciers in the steep flanks of high-mountain peaks, with potentially severe consequences to ice/rock avalanches, which may impact existing and new lakes, producing far-reaching outburst floods. Risks are also changing due to the socio-economic development in the Andean region and need to be considered using integrative approaches. Most research so far has concentrated on the Cordillera Blanca region where the most devastating disasters occurred during the 20th century. Very little is known about glacier and high-mountain hazards in the southern Peruvian Cordilleras of Cusco although some of the largest debris flows worldwide affected this region in recent years. In fact, very little is known about the nature, origin and exact dimensions of mass movements in this area, and long-term climatic records are neither available. Here we analyze these recent events in the Santa Teresa region based on field work, satellite images, available meteorological data, and numerical modeling of mass movements. These studies are part of a larger effort towards an integrative risk management. Most of the mass movements that caused disasters have their origin in glaciated catchments draining towards Santa Teresa with catchment sizes between about 100 and 300 km2, and glacier areas of 6 to 16 km2 per catchment. It is known that the enormous 1998 debris flow (ca. 25 million m3) that destroyed the Machu Picchu hydropower plant

  16. 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.

  17. Air Mass Frequency during Precipitation Events in the United States Northern Plains

    NASA Astrophysics Data System (ADS)

    Loveless, D. M.; Sharr, N. J.; Baum, A.; Contract, J. S.; DePasquale, R.; Godek, M. L.

    2013-12-01

    Since 1980, numerous billion-dollar disasters have affected the Northern Plains of the United States, including nine droughts and four floods. Given the region's large agricultural sector, the ability to accurately forecast the frequency and quantity of precipitation events here is imperative as it has a major impact on the economy of states in the region. The atmospheric environment present during precipitation events can largely be described by the presiding air mass conditions since air masses characterize a multitude of meteorological variables at one time over a large region. Therefore, understanding the relationship between air masses and rainfall episodes can contribute to improved precipitation forecasts. The goal of this research is to add knowledge to current understandings of the factors responsible for precipitation in the Northern Plains through an assessment of synoptic air mass conditions. The Spatial Synoptic Classification is used to categorize 30 years of daily air mass types across the region and daily precipitation is acquired from the United States Historical Climatological Network at stations in close proximity. Air mass frequencies are then analyzed for all regional precipitation events and rainfall categories are developed based on precipitation quantity. Both annual and seasonal air mass frequencies are assessed at the time of precipitation events. Additionally, air mass frequencies are obtained for positive and negative phases of the Pacific/North American Pattern to examine the influence of a teleconnection forcing factor on the air mass types responsible for producing precipitation quantities. Results indicate that the Transitional (TR) air mass, associated with changing air mass conditions commonly related to passing fronts, is not the leading producer of rainfall in the region. The TR is generally responsible for only 10-20% of regional precipitation, which often is classed in a heavy rainfall category. All moist air mass varieties are

  18. Influence of basketball shoe mass, outsole traction, and forefoot bending stiffness on three athletic movements.

    PubMed

    Worobets, Jay; Wannop, John William

    2015-09-01

    Prior research has shown that footwear can enhance athletic performance. However, public information is not available on what basketball shoe properties should be selected to maximise movement performance. Therefore, the purpose of the study was to investigate the influence of basketball shoe mass, outsole traction, and forefoot bending stiffness on sprinting, jumping, and cutting performance. Each of these three basketball shoe properties was systematically varied by ± 20% to produce three shoe conditions of varying mass, three conditions of varying traction, and three conditions of varying bending stiffness. Each shoe was tested by 20 recreational basketball players completing maximal effort sprints, vertical jumps, and a cutting drill. Outsole traction had the largest influence on performance, as the participants performed significantly worse in all tests when traction was decreased by 20% (p < 0.001), and performed significantly better in the cutting drill when traction was increased by 20% (p = 0.005). Forefoot bending stiffness had a moderate effect on sprint and cutting performance (p = 0.013 and p = 0.016 respectively) and shoe mass was found to have no effect on performance. Therefore, choosing a shoe with relatively high outsole traction and forefoot bending stiffness should be prioritised, and less concern should be focused on selecting the lightest shoe.

  19. A New Limb Movement Detector Enabling People with Multiple Disabilities to Control Environmental Stimulation through Limb Swing with a Gyration Air Mouse

    ERIC Educational Resources Information Center

    Shih, Ching-Hsiang; Chang, Man-Ling; Shih, Ching-Tien

    2010-01-01

    This study assessed whether two persons with multiple disabilities would be able to control environmental stimulation using limb swing with a gyration air mouse and a newly developed limb movement detection program (LMDP, i.e., a new software program that turns a gyration air mouse into a precise limb movement detector). The study was performed…

  20. Characterization of large mass movements occurred in the Italian Alps using seismic monitoring networks

    NASA Astrophysics Data System (ADS)

    Coviello, Velio; De Santis, Francesca; Chiarle, Marta; Arattano, Massimo; Godio, Alberto

    2014-05-01

    Passive seismic monitoring techniques have been profusely adopted to detect seismic sources induced by slope deformation and landslide propagation. Seismic signal processing can provide relevant information on the dynamics of unstable slopes, and may allow the identification of collapse precursors. Otherwise, seismic sensors have been used to characterize the volume and propagation velocity of rock-slides and debris-flows. For these purposes, geophone arrays are usually installed in specific monitoring sites. However, also a broadband seismic network can be used to identify signals originated by the detachment and movements of large masses. One advantage of using these networks would be the ability to detect remote events that might otherwise go unnoticed for weeks or months. Furthermore, even if often recorded at a distance, the spectral analysis of the low frequency content of the recorded signal may allow a preliminary characterization of the phenomenon. We selected five well known large mass movements occurred in the Italian Alps with volumes between 300.000 cubic meter (Monte Rosa rock avalanche, 2007) and 34.000.000 cubic meter (Val Pola rock avalanche, 1987). On average, seismic stations located up to 40 km far from these events were able to detect them, except for the Val Pola rock avalanche which was recorded at a distance greater than 100 km. As already observed by other authors, for these phenomena common signal characteristics include emergent onsets on all channels, slowly decaying tails and a triangular spectrogram shape. For this study we used different ground velocity sensors and considering the event magnitude, the distance source-receiver and to ensure a flat frequency response we focused on the 1-40 Hz frequency band. In this work these five large slope instabilities are described and the associated seismograms are presented and analyzed together with a first discussion of their spectral characteristics.

  1. Spring Defrosting of Mass-Movement Material at South High Latitudes

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Southern hemisphere spring on Mars will begin this year around May 6, 2003. During the spring, the MOC operations team will be documenting changes as the seasonal carbon dioxide frost cap retreats southward. In preparation for this year's southern spring, the team has been examining images obtained during the last southern spring, which occurred in 2001.

    This pair of images shows gullies and associated scars formed by mass-movement down a slope in the south polar region. The first view, in mid-spring, was acquired in August 2001; it shows a terrain that is largely devoid of the frost that covered everything during winter. However, the aprons of debris from the mass-movements (landslides) are still frosted. By late spring, in the second picture (right), the frost on the aprons had finally sublimed away, and the debris was seen to be not much brighter than their surroundings. The second picture was taken in November 2001, about a week before the first day of summer.

    The fact that the aprons of debris retained frost in mid-spring, whereas the surrounding terrain did not, probably indicates that the debris underlying the frost has different thermal properties than the surroundings. The debris might be more coarse-grained (sand or gravel, perhaps), and remained cooler in the daytime than the surrounding, dust-mantled surfaces.

    The images are both illuminated from the bottom/lower right. North is toward the bottom, and the area imaged is located near 70.9oS, 339.3oW.

  2. A determination of character and frequency changes in air masses using a spatial synoptic classification

    NASA Astrophysics Data System (ADS)

    Kalkstein, Laurence S.; Sheridan, Scott C.; Graybeal, Daniel Y.

    1998-09-01

    Of the numerous climate change studies which have been performed, few of these have analyzed recent trends using an air mass-based approach. The air mass approach is superior to simple trend analysis, as it can identify patterns which may be too subtle to influence the entire climate record. The recently-developed spatial synoptic classification (SSC) is thus used to identify trends over the contiguous United States for summer and winter seasons from 1948 to 1993. Both trends in air mass frequency and character have been assessed.The most noteworthy trend in frequency is a decline in air mass transitional days (TR) during both seasons. In winter, decreases of up to 1% per decade are noted in parts of the central U.S. Other notable trends include a decrease in moist tropical (MT) air in winter, and an increase in MT in summer over the southeastern states.Numerous national and local air mass character changes have been uncovered. A large overall upward trend in cloudiness is noted in summer. All air masses feature an overnight increase, yet afternoon cloudiness increases are generally limited to the three dry air masses. Also in summer, a significant warming and increase in dew point of MT air has occurred at many locales. The most profound winter trend is a large decrease in dew point (up to 1.5°C per decade) in the dry polar (DP) air mass over much of the eastern states.

  3. The impact of air mass advection on aerosol optical properties over Gotland (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Zdun, Agnieszka; Rozwadowska, Anna; Kratzer, Susanne

    2016-12-01

    In the present paper, measurements of aerosol optical properties from the Gotland station of the AERONET network, combined with a two-stage cluster analysis of back trajectories of air masses moving over Gotland, were used to identify the main paths of air mass advection to the Baltic Sea and to relate them to aerosol optical properties, i.e. the aerosol optical thickness at the wavelength λ = 500 nm, AOT (500) and the Ångström exponent for the spectral range from 440 to 870 nm, α(440,870). One- to six-day long back trajectories ending at 300, 500 and 3000 m above the station were computed using the HYSPLIT model. The study shows that in the Gotland region, variability in aerosol optical thickness AOT(500) is more strongly related to advections in the boundary layer than to those in the free troposphere. The observed variability in AOT(500) was best explained by the advection speeds and directions given by clustering of 4-day backward trajectories of air arriving in the boundary layer at 500 m above the station. 17 clusters of 4-day trajectories arriving at altitude 500 m above the Gotland station (sea level) derived using two-stage cluster analysis differ from each other with respect to trajectory length, the speed of air mass movement and the direction of advection. They also show different cluster means of AOT(500) and α(440,870). The cluster mean AOT(500) ranges from 0.342 ± 0.012 for the continental clusters M2 (east-southeast advection with moderate speed) and 0.294 ± 0.025 for S5 (slow south-southeast advection) to 0.064 ± 0.002 and 0.069 ± 0.002 for the respective marine clusters L3 (fast west-northwest advection) and M3 (north-northwest advection with moderate speed). The cluster mean α(440,870) varies from 1.65-1.70 for the short-trajectory clusters to 0.98 ± 0.03 and 1.06 ± 0.03 for the Arctic marine cluster L4 (fast inflow from the north) and marine cluster L5 (fast inflow from the west) respectively.

  4. Quantification of Process in AN Actively Eroding Gully-Mass Movement Complex, Waipaoa Catchment, New Zealand

    NASA Astrophysics Data System (ADS)

    Fuller, I. C.; Taylor, R.; Massey, C. I.; Marden, M.

    2012-12-01

    Tarndale Gully is a major fluvio-mass movement gully complex in the headwaters of the Waipaoa catchment, contributing c.3% of the Waipaoa sediment yield (Marden et al., 2008). Using a combination of airborne LiDAR (2005) and Terrestrial Laser Scanning (2007, 2008, 2010, 2011), this paper quantifies sediment delivery processes and slope-channel connectivity in this major contributor to the Waipaoa sediment cascade over a seven year period. Building on previous work, which inferred connectivity characteristics using RTK-dGPS surveys of the fan fed by the gully-mass movement complex (Fuller & Marden, 2011), acquisition of terrain data from high-resolution surveys of the whole gully-fan system provides new insights into slope process and slope-channel linkages operating in the complex. Raw terrain data from the airborne and ground-based laser scans were converted into raster DEMs in Arc-GIS using inverse distance weighting interpolation to a vertical accuracy between surveys of < ±0.1m. Using GIS maths functions, grid elevations in each successive DEM were subtracted from the previous DEM to provide models of change across the gully and fan complex. Deposition equates to positive vertical change, while erosion to negative vertical change in these models. Total annualised erosion equates to an average of 125,000m3 generated from the gully-mass movement complex, which is a product of debris flow, slumping and surface erosion by runoff (gullying in the conventional sense). Erosion rates from the gully complex appear to have been consistent year to year between 2005 and 2011. While the average annual volume of sediment exported to the stream system equates to 57,328 m3, this figure varies from 25,000 m3 to 110,000 m3 with no distinct correlation to rainfall. Fluctuations in stored sediment volumes account for this variation, where a critical mass in the upper fan initiates downstream progradation of sediment, building-up the lower fan. When an unknown threshold is reached

  5. 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

  6. Relief unity emulator and slope stability simulator applied to mass movement occurrence analysis in slope evolution

    NASA Astrophysics Data System (ADS)

    Colangelo, Antonio C.

    2010-05-01

    , effective stress, water retention factor, vegetation canopy unit weight and height. All these considering variables were calculated for each cell in the synthetic slope system, that is defined laterally by crossing of equivalence topographic belt with inter-profile space and, vertically by soil surface and potential rupture surface, that may be soil-regolith or regolith-rock transition. Therefore, with this device is possible, from a single generatrix profile, to design infinity of slope evolution ways by means of definition of boundary value of the models. When in the "potential rupture surface" is produced an "effective potential rupture surface", factor of safety less than unity, the soil fails and the slope stability simulator generate a mass movement prototype. A number of interesting and verisimilar 3D mass movement digital experiments may be performed for an inferred neogenic slope evolution time scale.

  7. Effects of lighting and air movement on temperatures in reproductive organs of plants in a closed plant growth facility

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Hirai, H.

    Temperature increases in plant reproductive organs such as anthers and stigmas could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions without adequately controlled environments in closed plant growth facilities. There is a possibility such a situation could occur in Bioregenerative Life Support Systems under microgravity conditions in space because there will be little natural convective or thermal mixing. This study was conducted to determine the temperature of the plant reproductive organs as affected by illumination and air movement under normal gravitational forces on the earth and to make an estimation of the temperature increase in reproductive organs in closed plant growth facilities under microgravity in space. Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at air temperatures of 10 11 °C. Compared to the air temperature, temperatures of petals, stigmas and anthers of strawberry increased by 24, 22 and 14 °C, respectively, after 5 min of lighting at an irradiance of 160 W m-2 from incandescent lamps. Temperatures of reproductive organs and leaves of strawberry were significantly higher than those of rice. The temperatures of petals, stigmas, anthers and leaves of strawberry decreased by 13, 12, 13 and 14 °C, respectively, when the air velocity was increased from 0.1 to 1.0 ms-1. These results show that air movement is necessary to reduce the temperatures of plant reproductive organs in plant growth facilities.

  8. Minimum acceleration with constraints of center of mass: a unified model for arm movements and object manipulation.

    PubMed

    Leib, Raz; Karniel, Amir

    2012-09-01

    Daily interaction with the environment consists of moving with or without objects. Increasing interest in both types of movements drove the creation of computational models to describe reaching movements and, later, to describe a simplified version of object manipulation. The previously suggested models for object manipulation rely on the same optimization criteria as models for reaching movements, yet there is no single model accounting for both tasks that does not require reminimization of the criterion for each environment. We suggest a unified model for both cases: minimum acceleration with constraints for the center of mass (MACM). For point-to-point reaching movement, the model predicts the typical rectilinear path and bell-shaped speed profile as previous criteria. We have derived the predicted trajectories for the case of manipulating a mass-on-spring and show that the predicted trajectories match the observations of a few independent previous experimental studies of human arm movement during a mass-on-spring manipulation. Moreover, the previously reported "unusual" trajectories are also well accounted for by the proposed MACM. We have tested the predictions of the MACM model in 3 experiments with 12 subjects, where we demonstrated that the MACM model is equal or better (Wilcoxon sign-rank test, P < 0.001) in accounting for the data than three other previously proposed models in the conditions tested. Altogether, the MACM model is currently the only model accounting for reaching movements with or without external degrees of freedom. Moreover, it provides predictions about the intermittent nature of the neural control of movements and about the dominant control variable.

  9. 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.

  10. A brief survey of GIS in mass-movement studies, with reflections on theory and methods

    NASA Astrophysics Data System (ADS)

    Alexander, David E.

    This paper surveys the evolution and progress of landslide studies with particular reference to the use of geographic information systems (GIS) in setting the agenda for research. The article begins with a critical discussion of the mass-movement classification problem and notes that it has been thornier and more complex than it has for many other types of extreme natural phenomena. The evolution of slope instability studies is charted from its descriptive, field-based origins to recent higher levels of understanding. On the one hand there has been a shift from static to dynamic modelling of slope processes using digital simulation and computer graphics, while on the other hand, automated cartography, GIS and remote sensing have enabled regional studies at last to predominate over site-based ones. However, GIS often tends to favour inductive study design, and so does the continuing emphasis on classification. The low level of insight generated by inductive studies has inhibited the development of more interdisciplinary frameworks for study. It has also proved difficult to reorient landslide studies to tackle slope instability problems with greater sensitivity to the stakeholders' needs. Finally, although social, administrative, political, cultural and perceptual aspects of landslides have been neglected, there are signs of a new interest in these important aspects.

  11. Modeling and forecasting daily movement of ambient air mean PM₂.₅ concentration based on the elliptic orbit model with weekly quasi-periodic extension: a case study.

    PubMed

    Yang, Zong-chang

    2014-01-01

    Nowadays, the issue of air pollution has continuously been a global public health concern. Modeling and forecasting daily movement of ambient air mean PM2.5 concentration is an increasingly important task as it is intimately associated with human health that the air pollution has unignorable negative effects in reducing air quality, damaging environment, even causing serious harm to health. It is demonstrated that daily movement of mean PM₂.₅ concentration approximately exhibits weekly cyclical variations as daily particle pollution in the air is largely influenced by human daily activities. Then, based on weekly quasi-periodic extension for daily movement of mean PM₂.₅ concentration, the called elliptic orbit model is proposed to describe its movement. By mapping daily movement of mean PM₂.₅ concentration as one time series into the polar coordinates, each 7-day movement is depicted as one elliptic orbit. Experimental result and analysis indicate workability and effectiveness of the proposed method. Here we show that with the weekly quasi-periodic extension, daily movements of mean PM₂.₅ concentration at the given monitoring stations in Xiangtan of China are well described by the elliptic orbit model, which provides a vivid description for modeling and prediction daily movement of mean PM₂.₅ concentration in a concise and intuitive way.

  12. An evaluation of interventions for reducing the risk of PRRSV introduction to filtered farms via retrograde air movement through idle fans.

    PubMed

    Alonso, Carmen; Otake, Satoshi; Davies, Peter; Dee, Scott

    2012-06-15

    Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically significant pathogen of pigs that can be transported via the airborne route out to 9.1 km. To reduce this risk, large swine facilities have started to implement systems to filter contaminated incoming air. A proposed means of air filtration failure is the retrograde movement of air (back-drafting) from the external environment into the animal air space through non-filtered points such as idle wall fans; however, this risk has not been validated. Therefore, the purpose of this study was threefold: (1) to prove that PRRSV introduction via retrograde air movement through idle fans is a true risk; (2) to determine the minimum retrograde air velocity necessary to introduce PRRSV to an animal airspace from an external source; and (3) to evaluate the efficacy of different interventions designed to reduce this risk. A retrograde air movement model was used to test a range of velocities and interventions, including a standard plastic shutter, a plastic shutter plus a canvas cover, a nylon air chute, an aluminum shutter plus an air chute and a double shutter system. Results indicated that retrograde air movement is a real risk for PRRSV introduction to a filtered air space; however, it required a velocity of 0.76 m/s. In addition, while all the interventions designed to reduce this risk were superior when compared to a standard plastic shutter, significant differences were detected between treatments.

  13. 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

  14. 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.

  15. Movement and orientation decision modeling of Rhyzopertha dominica (Coleoptera: Bostrichidae) in the grain mass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain stored in bins is initially a relatively homogenous resource patch for stored-product insects, but over time spatial pattern in insect distribution can form, due in part to insect movement patterns. However, the factors that influence stored-product insect movement patterns in grain are not w...

  16. High mobility of large mass movements: a study by means of FEM/DEM simulations

    NASA Astrophysics Data System (ADS)

    Manzella, I.; Lisjak, A.; Grasselli, G.

    2013-12-01

    Large mass movements, such as rock avalanches and large volcanic debris avalanches are characterized by extremely long propagation, which cannot be modelled using normal sliding friction law. For this reason several studies and theories derived from field observation, physical theories and laboratory experiments, exist to try to explain their high mobility. In order to investigate more into deep some of the processes recalled by these theories, simulations have been run with a new numerical tool called Y-GUI based on the Finite Element-Discrete Element Method FEM/DEM. The FEM/DEM method is a numerical technique developed by Munjiza et al. (1995) where Discrete Element Method (DEM) algorithms are used to model the interaction between different solids, while Finite Element Method (FEM) principles are used to analyze their deformability being also able to explicitly simulate material sudden loss of cohesion (i.e. brittle failure). In particular numerical tests have been run, inspired by the small-scale experiments done by Manzella and Labiouse (2013). They consist of rectangular blocks released on a slope; each block is a rectangular discrete element made of a mesh of finite elements enabled to fragment. These simulations have highlighted the influence on the propagation of block packing, i.e. whether the elements are piled into geometrical ordinate structure before failure or they are chaotically disposed as a loose material, and of the topography, i.e. whether the slope break is smooth and regular or not. In addition the effect of fracturing, i.e. fragmentation, on the total runout have been studied and highlighted.

  17. Numerical Simulation of Air Mass Modification Over the East China Sea during the Winter Season

    NASA Astrophysics Data System (ADS)

    Hsu, Wu-Ron

    Air mass modification over the East China Sea during cold air outbreaks in the winter season was simulated by utilizing a high-resolution numerical model. The model includes most of the major physical processes, such as, surface exchange of heat and moisture between water and air; condensation and evaporation; and vertical turbulent transfer of heat, moisture, and momentum. The simulated convective boundary layer (CBL) consists of a surface layer, a subcloud layer, and a cloud layer. It is capped by an inversion with strong temperature and moisture gradients. Mesoscale cellular convection (MCC) embedded within the convective layer moves along with the mean wind. The average aspect ratio of the cells is 17.5, which agrees with observed aspect ratios for convective cells over the East China Sea. The upward convective motion correlates very well with the appearance of clouds, higher temperature, and higher moisture content in the CBL. The effects of diabatic heating were found to be very important in driving the thermal convection. Without the release of latent heat, the convective layer would be very shallow, and the convective motion would be greatly suppressed. Even though the formulation and dissipation of a cloud is associated with the movement of the resolvable scale MCC, the vertical transport of heat and moisture is achieved mainly by the unresolvable turbulent eddies. The distribution of specific humidity during the passage of the surface front reveals the moisture being pushed upward along the frontal surface as observed. The cold and dry air behind the cold front is quickly modified by strong convection over the warm water surface, especially over the Kuroshio Current. A cloud-free region exists near the coast where the CBL is too shallow for clouds to develop. A layer of stratocumulus forms downstream from the cloud-free region. The depth of the CBL increases toward the Kuroshio Current due to strong heat and moisture fluxes from the water surface. The CBL

  18. Elemental composition of different air masses over Jeju Island, South Korea

    NASA Astrophysics Data System (ADS)

    Kang, Jeongwon; Choi, Man-Sik; Yi, Hi-Il; Jeong, Kap-Sik; Chae, Jung-Sun; Cheong, Chang-Sik

    2013-03-01

    We investigated the characteristics (concentrations and compositional changes) of atmospheric elements in total suspended particulates through source-receptor relationships using cluster analyses to classify air mass back-trajectories arriving at Gosan, Jeju Island, South Korea, from October 2003 to December 2008. Five trajectory clusters were chosen to explain the transport regimes. Continental outflows of natural and anthropogenic aerosols from Asian dust source regions and eastern China during the colder period could increase element concentrations at Gosan. Elemental levels at Gosan decreased in air masses that passed over marine regions (East China Sea, Pacific Ocean/southern side of Kyushu Island in Japan, and East Sea/southern side of South Korea) during the warmer rainy period due to lower source intensity and dilution by the marine air mass. Anthropogenic pollutants were often major components in air masses passing over marine regions. Air mass characterization by elemental concentration and composition revealed that enrichment by non-sea-salt sulfur in the air mass originated from eastern China, indicative of the main sulfur emitter in northeast Asia. The apportionment of V and Ni by principal component analysis as a marker of heavy oil combustion suggested different residence times and deposition rates from other anthropogenic components in the air. Regionally intermediate concentrations of pollutants were found in the atmosphere over the Korean peninsula.

  19. Mass movement and storms in the drainage basin of Redwood Creek, Humboldt County, California: a progress report

    USGS Publications Warehouse

    Harden, Deborah Reid; Janda, Richard J.; Nolan, K. Michael

    1978-01-01

    Numerous active landslides are clearly significant contributors to high sediment loads in the Redwood Creek basin. Field and aerial-photograph inspections indicate that large mass-movement features, such as earthflows and massive streamside debris slides, occur primarily in terrain underlain by unmetamorphosed or slightly metamorphosed sedimentary rocks. These features cannot account for stream sediment derived from schist. Observed lithologic heterogeneity of stream sediment therefore suggests that large-scale mass movement is only one part of a complex suite of processes supplying sediment to streams in this basin. Other significant sediment contributors include various forms of fluvial erosion and small-scale discrete mass failures, particularly on oversteepened hillslopes adjacent to perennial streams. Photo-interpretive studies of landslide and timber-harvest history adjacent to Redwood Creek, together with analysis of regional precipitation and runoff records for six flood-producing storms between 1953 and 1975, indicate that loci and times of significant streamside landsliding are influenced by both local storm intensity and streamside logging. Analysis of rainfall records and historic accounts indicates that the individual storms comprising a late-19th-century series of storms in northwestern California were similar in magnitude and spacing to those of the past 25 years. The recent storms apparently initiated more streamside landslides than comparable earlier storms, which occurred prior to extensive road construction and timber harvest. Field observations and repeated surveys of stake arrays at 10 sites in the basin indicate that earthflows are especially active during prolonged periods of moderate rainfall; but that during brief intense storms, fluvial processes are the dominant erosion mechanism. Stake movement occurs mostly during wet winter months. Spring and summer movement was detected at some moist streamside sites. Surveys of stake arrays in two

  20. Creep: An underrated type of mass movement on gently dipping hill slopes - examples from the Eastern Alpine foreland

    NASA Astrophysics Data System (ADS)

    Leopold, Philip; Draganits, Erich; Heiss, Gerhard

    2010-05-01

    Creep, as a very slow type of mass movement was first described by Terzahgi (1950) und Haefeli (1954, 1967). Terzaghi (1950) pointed out that creep represents an own type of mass movement cannot be compared with other types, such as slides, as creep occurs without rupture. According to him other mechanical laws than those that typically apply for mass movements, have to be determined for creep. In a more recent classification of mass movements, creep is described as slow earthflow within the flow type of movement (Highland & Bobrowsky, 2008). Aside from different ways of categorization of landslides, a very slow, imperceptible rate of movement is still considered characteristic for creep. Recent geological and geomorphological investigations of all kind of mass movements in the Eastern Alpine foreland in Austria (Eastern part of the Styrian basin, Oberpullendorf basin, Eisenstadt basin) showed that creep is not only widespread, but is in fact the most common type of mass movement in the Neogene sediments of the basins. More than 180 previously unrecognized zones of creep have been classified. Statistical analysis indicates that in some of the investigated areas creep occurs typically on slopes with gradients between only 10-35°. Movement rates are very low, inclinometer and other measurements show displacement rates in the range of a few centimeters per year. Therefore these mass movements have previously remained unnoticed by the population, local authorities and engineers. As a result there have been misjudgments in the land use-, building- and infrastructure planning which have caused a number of damages. Aside from the immediate implications creep has even more severe and longer term consequences. As a landforming process creep acts very constant over a very long period of time. Already Haefeli (1967) realized that creep occurs at a much lower rate of shear stress than the shear strength of the soil material. The rate of shear stress where creep starts to

  1. United States Air Force Role in Mass Atrocity Response Operations

    DTIC Science & Technology

    2012-05-17

    commands establish “off- the-shelf” plans for genocide-prone hot-spots around the world . These plans are crucial for two reasons. First , due to the...prevent or stop the occurrence of genocide. However, at the turn of the millennium, a movement was afoot in the world to change their policies. In... first case of genocide appeared in an international criminal tribunal.8 This 47- year void of action in the prevention or punishment of genocide was

  2. 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)

  3. On the evaluation of air mass factors for atmospheric near-ultraviolet and visible absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Perliski, Lori M.; Solomon, Susan

    1993-01-01

    The interpretation of UV-visible twilight absorption measurements of atmospheric chemical constituents is dependent on how well the optical path, or air mass factor, of light collected by the spectrometer is understood. A simple single scattering model and a Monte Carlo radiative transfer scheme have been developed to study the effects of multiple scattering, aerosol scattering, surface albedo and refraction on air mass factors for scattered light observations. At fairly short visible wavelengths (less than about 450 nm), stratospheric air mass factors are found to be relatively insensitive to multiple scattering, surface albedo and refraction, as well as aerosol scattering by background aerosols. Longer wavelengths display greater sensitivity to refraction and aerosol scattering. Tropospheric air mass factors are found to be highly dependent on aerosol scattering, surface albedo and, at long visible wavelengths (about 650 nm), refraction. Absorption measurements of NO2 and O4 are shown to support these conclusions.

  4. A Physical Experiment to determine the Impact of Atmospheric Condensation of Water Vapour on Surface Air Movement

    NASA Astrophysics Data System (ADS)

    Bunyard, Peter

    2014-05-01

    A physical experiment, in which atmospheric air is enclosed in two interconnecting 4.8-metre high insulated PVC columns, consistently gives results showing that the condensation of water vapor, precipitated by means of refrigeration coils, gives rise to detectable air movements, with air speeds of up to 0.1 m/s. Once the compressor, sited well away from the two columns, is shut down, heavy drops of precipitated water are obtained which funnel into a flask for collection and measurement. The results in kg.m-2 (mm) from the 20 m3 volume of enclosed air accord well (>90%) with the physical calculations based on water vapour as an ideal gas. Air flow, resulting from the highly localized condensation, is measured through the movement of light-weight gauzes and an anemometer. It has a circulation time of some two minutes, such that both columns show cooling and a significant reduction in specific humidity from 0.01 to 0.005 (kg water vapour to kg dry air, r) with a drop in relative humidity of up to 40 per cent. Air flow is minimal during the control, non-refrigeration period of the experiment but becomes substantial within a minute of the compressor being switched on. The negative partial pressure change peaks at as much as 0.4 Pa/s during the first 30 minutes but reduces to approx.0.08 Pa/s during the latter part of the 110 minute-long experiment. Airflow displays an inverse relationship to the partial pressure change, initially rising rapidly and then reducing before returning to zero once refrigeration has been switched off. Inverse correlations of up to 0.8 or higher between the partial pressure reduction and the airflow are obtained routinely. Semi-aquatic vegetation from the nearby marshland enhances precipitation, suggesting that evapotranspiration adds significantly to humidity. Without vegetation the condensation rate is 0.06 to 0.07 millimol.m-3.s-1 on average compared with 0.11 when vegetation is present. Cooling, by some 2°C, combined with a reduction in

  5. A Physical Experiment to determine the Impact of Atmospheric Condensation of Water Vapor on Surface Air Movement

    NASA Astrophysics Data System (ADS)

    Bunyard, P. P.; Nechev, P.

    2013-12-01

    A physical experiment, in which atmospheric air is enclosed in two interconnecting 4.8-metre high insulated PVC columns, consistently gives results showing that the condensation of water vapor, precipitated by means of refrigeration coils, gives rise to detectable air movements, with air speeds of up to 0.1 m/s. Once the compressor, sited well away from the two columns, is shut down, heavy drops of precipitated water are obtained which funnel into a flask for collection and measurement. The results in kg.m-2 (mm) from the 20 m3 volume of enclosed air accord well (>90%) with the physical calculations based on water vapor as an ideal gas. Air flow, resulting from the highly localized condensation, is measured through the movement of light-weight gauzes and an anemometer. It has a circulation time of some two minutes, such that both columns show cooling and a significant reduction in specific humidity from 0.01 to 0.005 (kg water vapor to kg dry air, r) with a drop in relative humidity of up to 40 per cent. Air flow is minimal during the control, non-refrigeration period of the experiment but becomes substantial within a minute of the compressor being switched on. The negative partial pressure change peaks at as much as 0.4 Pa/s during the first 30 minutes but reduces to approx. 0.08 Pa/s during the latter part of the 110 minute- long experiment. Airflow displays an inverse relationship to the partial pressure change, initially rising rapidly and then reducing before returning to zero once refrigeration has been switched off. Inverse correlations of up to 0.8 or higher between the partial pressure reduction and the airflow are obtained routinely. Semi-aquatic vegetation from the nearby marshland enhances precipitation, suggesting that evapotranspiration adds significantly to humidity. Without vegetation the condensation rate is 0.06 to 0.07 millimol.m-3.s-1 on average compared with 0.11 when vegetation is present. Cooling, by some 2°C, combined with a reduction in

  6. A Systematic Review of the Health Impacts of Mass Earth Movements (Landslides)

    PubMed Central

    Kennedy, Iain T R; Petley, Dave N.; Williams, Richard; Murray, Virginia

    2015-01-01

    Background. Mass ground movements (commonly referred to as ‘landslides’) are common natural hazards that can have significant economic, social and health impacts. They occur as single events, or as clusters, and are often part of ‘disaster’ chains, occurring secondary to, or acting as the precursor of other disaster events. Whilst there is a large body of literature on the engineering and geological aspects of landslides, the mortality and morbidity caused by landslides is less well documented. As far as we are aware, this is the first systematic review to examine the health impacts of landslides. Methods. The MEDLINE, EMBASE, CINAHL, SCOPUS databases and the Cochrane library were systematically searched to identify articles which considered the health impacts of landslides. Case studies, case series, primary research and systematic reviews were included. News reports, editorials and non-systematic reviews were excluded. Only articles in English were considered. The references of retrieved papers were searched to identify additional articles. Findings. 913 abstracts were reviewed and 143 full text articles selected for review. A total of 27 papers reporting research studies were included in the review (25 from initial search, 1 from review of references and 1 from personal correspondence). We found a limited number of studies on the physical health consequences of landslides. Only one study provided detail of the causes of mortality and morbidity in relation a landslide event. Landslides cause significant mental health impacts, in particular the prevalence of PTSD may be higher after landslides than other types of disaster, though these studies tend to be older with only 3 papers published in the last 5 years, with 2 being published 20 years ago, and diagnostic criteria have changed since they were produced. Discussion. We were disappointed at the small number of relevant studies, and the generally poor documentation of the health impacts of landslides

  7. Caesium-137 as Indicator of Present Mass-Movement and Erosion Processes

    NASA Astrophysics Data System (ADS)

    Supper, R.; Baron, I.; Winkler, E.; Motschka, K.; Jaritz, W.; Moser, G.; Carman, M.

    2012-04-01

    with bare surfaces of active landslides, earthflows, erosion gullies, spring areas and zones of estimated higher superficial water flow. On the other hand, the flat and stable areas have a relatively high content of this isotope. As conclusion we can say that the 137Cs distribution could be used as a parameter for mapping of present active mass-movement, wash-out, and other superficial erosion processes that have occurred in Europe after the 1986 Chernobyl event. This study was done within the framework of the SafeLand project funded by the European Commission's FP7 Programme.

  8. Globally referenced real time monitoring of mass movements using monoscopic time-lapse photography.

    NASA Astrophysics Data System (ADS)

    Kenner, Robert; Phillips, Marcia; Buchroithner, Manfred

    2016-04-01

    The creep movement of a rock glacier was monitored in daily resolution using images of an automatic in-situ time-lapse camera (AC). Displacements were calculated between the images in 2D image coordinates using the imaging velocimetry algorithm of Roesgen and Totaro, 1995. To georeference and scale these displacements, a creep velocity field captured once by a terrestrial laser scan (TLS) repeat measurement was used. The laser scan point cloud and the creep velocity vector field were projected in image coordinates of the AC to obtain a georeferencing mask, a scale mask and an azimuth mask for the 2D displacements calculated between two images. The scale mask was obtained by comparing the TLS derived displacement vectors with those of the AC, referring to a common measurement period. The automatic procedure includes the following work steps: 1. Offsets between two images are identified and corrected based on image parts representing unchanged terrain. 2. 2D displacements are calculated between all chronological image sequences. 3. Faulty displacement vectors are eliminated based on a predefined threshold for spatial direction differences. 4. The remaining displacements are georeferenced, scaled and attributed with individual displacement directions (azimuths) in global coordinates. 5. In addition to the displacement values, displacement velocities and accelerations are calculated using the date of the images. 6. For chronologically successive displacement vector fields, the spatial mean of the relative velocity is defined and expressed as a percentage of the first displacement velocity in the series. The time series of the relative velocities is expressed in chart form. 7. The spatial resolution of all georeferenced output data sets is homogenized, as they were influenced by the central projection of the photos. The described procedure proved to be a reliable, low cost method to monitor mass wasting processes. Even under difficult conditions, like thin snow coverage

  9. A systematic review of the health impacts of mass Earth movements (landslides).

    PubMed

    Kennedy, Iain T R; Petley, Dave N; Williams, Richard; Murray, Virginia

    2015-04-30

    Background. Mass ground movements (commonly referred to as 'landslides') are common natural hazards that can have significant economic, social and health impacts. They occur as single events, or as clusters, and are often part of 'disaster' chains, occurring secondary to, or acting as the precursor of other disaster events. Whilst there is a large body of literature on the engineering and geological aspects of landslides, the mortality and morbidity caused by landslides is less well documented. As far as we are aware, this is the first systematic review to examine the health impacts of landslides. Methods. The MEDLINE, EMBASE, CINAHL, SCOPUS databases and the Cochrane library were systematically searched to identify articles which considered the health impacts of landslides. Case studies, case series, primary research and systematic reviews were included. News reports, editorials and non-systematic reviews were excluded. Only articles in English were considered. The references of retrieved papers were searched to identify additional articles. Findings. 913 abstracts were reviewed and 143 full text articles selected for review. A total of 27 papers reporting research studies were included in the review (25 from initial search, 1 from review of references and 1 from personal correspondence). We found a limited number of studies on the physical health consequences of landslides. Only one study provided detail of the causes of mortality and morbidity in relation a landslide event. Landslides cause significant mental health impacts, in particular the prevalence of PTSD may be higher after landslides than other types of disaster, though these studies tend to be older with only 3 papers published in the last 5 years, with 2 being published 20 years ago, and diagnostic criteria have changed since they were produced. Discussion. We were disappointed at the small number of relevant studies, and the generally poor documentation of the health impacts of landslides. Mental

  10. 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)

  11. 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...

  12. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    NASA Astrophysics Data System (ADS)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  13. 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.

  14. Erroneous mass transit system and its tended relationship with motor vehicular air pollution (An integrated approach for reduction of urban air pollution in Lahore).

    PubMed

    Aziz, Amer; Bajwa, Ihsan Ullah

    2008-02-01

    Air pollution is threat to the lives of people living in big cities of Pakistan. In Lahore 1,250 people die annually because of air pollution. Mass transit system that can be put forth as solution to urban air pollution is contingent with right choice of system and its affiliation with motorized vehicles and nature of urban air pollution. Existing mass transit system in Lahore due to untrue operation causes surfeit discharge of motor vehicular carbon monoxide. Tended relationships of mass transit system with motorized vehicles and urban air pollution are quite noteworthy. The growing motor vehicles (a consequence of flawed public mass transit system) are potential source of urban air pollution. This paper attempts to highlight correlations and regression curves of existing mass transit system. Further it recommends a two facet approach for reduction of motor vehicular air pollution in Lahore.

  15. The environmental significance of the remobilisation of ancient mass movements in the Atbara Tekeze headwaters, Northern Ethiopia

    NASA Astrophysics Data System (ADS)

    Nyssen, Jan; Moeyersons, Jan; Poesen, Jean; Deckers, Jozef; Haile, Mitiku

    2003-01-01

    Old landslides are prominent features in the landscape around Hagere Selam, Tigray Highlands, Ethiopia. The available evidence suggests their Late Pleistocene to Middle Holocene age and conditions of soil humidity. The affected geological layers, often silicified lacustrine deposits prone to sliding, rest upon or above the water holding Amba Aradam sandstone aquifer. Three examples of present-day (remobilisation of old) mass movements are illustrated and discussed. The aims of the study were to unravel the environmental conditions of the present-day remobilisation of ancient flows, as well as those of first-time landslides. The first two mass movements discussed are slumps, located in areas with vigorous regeneration of (grassy) vegetation. Their activation is thought to be the consequence of an increase in infiltration capacity of the soils under regenerating vegetation. One of these slumps had a horizontal movement of the order of 10-20 m in 1 day. The other case is the remobilisation of the May Ntebteb debris flow below the Amba Aradam sandstone cliff. The debris flow presently creeps downslope at a rate of 3-6 cm year -1. Palynological evidence from tufa shows that the reactivation of the flow started 70 years ago. Shear resistance measurements indicate the danger for continuous or prefailure creep. From the soil mechanics point of view, the reactivation of the debris flow is due to the combination of two factors: (1) the reduction of flow confining pressures as a result of gully incision over the last hundred years, and (2) the increase of seepage pressure as a consequence of the cumulative effect of this incision and the increase in infiltration rates on the lobe since grazing and woodcutting have been prohibited 8 years ago. The role of such exclosures as possible landslide triggers is discussed. From the geomorphological point of view, the ancient movements and their present-day reactivation cannot be compared: the ancient movements led to the development

  16. Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements.

    PubMed

    Crevecoeur, F; McIntyre, J; Thonnard, J-L; Lefèvre, P

    2014-07-15

    Moving requires handling gravitational and inertial constraints pulling on our body and on the objects that we manipulate. Although previous work emphasized that the brain uses internal models of each type of mechanical load, little is known about their interaction during motor planning and execution. In this report, we examine visually guided reaching movements in the horizontal plane performed by naive participants exposed to changes in gravity during parabolic flight. This approach allowed us to isolate the effect of gravity because the environmental dynamics along the horizontal axis remained unchanged. We show that gravity has a direct effect on movement kinematics, with faster movements observed after transitions from normal gravity to hypergravity (1.8g), followed by significant movement slowing after the transition from hypergravity to zero gravity. We recorded finger forces applied on an object held in precision grip and found that the coupling between grip force and inertial loads displayed a similar effect, with an increase in grip force modulation gain under hypergravity followed by a reduction of modulation gain after entering the zero-gravity environment. We present a computational model to illustrate that these effects are compatible with the hypothesis that participants partially attribute changes in weight to changes in mass and scale incorrectly their motor commands with changes in gravity. These results highlight a rather direct internal mapping between the force generated during stationary holding against gravity and the estimation of inertial loads that limb and hand motor commands must overcome.

  17. Discrete element modeling of the mass movement and loose material supplying the gully process of a debris avalanche in the Bayi Gully, Southwest China

    NASA Astrophysics Data System (ADS)

    Zhou, Jia-wen; Huang, Kang-xin; Shi, Chong; Hao, Ming-hui; Guo, Chao-xu

    2015-03-01

    The dynamic process of a debris avalanche in mountainous areas is influenced by the landslide volume, topographical conditions, mass-material composition, mechanical properties and other factors. A good understanding of the mass movement and loose material supplying the gully process is very important for understanding the dynamic properties of debris avalanches. Three-dimensional particle flow code (PFC3D) was used to simulate a debris avalanche in Quaternary deposits at the Bayi Gully, Southwest China. FORTRAN and AutoCAD were used for the secondary development to display the mass movement process and to quantitatively describe the mass movement and loose material supplying the gully process. The simulated results show that after the landslide is initiated, the gravitational potential energy is converted into kinetic energy with a variation velocity for the sliding masses. Two stages exist for the average-movement velocity: the acceleration stage and the slowdown stage, which are influenced by the topographical conditions. For the loose materials supplying the gully process, the cumulative volume of the sliding masses into the gully gradually increases over the time. When the landslide volume is not large enough, the increasing landslide volume does not obviously influence the movement process of the sliding masses. The travel distance and movement velocity increase with the decreasing numerical parameters, and the mass-movement process is finished more quickly using low-value parameters. The deposition area of the sliding masses decreases with the increasing numerical parameters and the corresponding deposition thickness increases. The mass movement of the debris avalanche is not only influenced by the mechanical parameters but is also controlled by the topographical conditions.

  18. Monolithic mass sensor fabricated using a conventional technology with attogram resolution in air conditions

    NASA Astrophysics Data System (ADS)

    Verd, J.; Uranga, A.; Abadal, G.; Teva, J.; Torres, F.; Pérez-Murano, F.; Fraxedas, J.; Esteve, J.; Barniol, N.

    2007-07-01

    Monolithic mass sensors for ultrasensitive mass detection in air conditions have been fabricated using a conventional 0.35μm complementary metal-oxide-semiconductor (CMOS) process. The mass sensors are based on electrostatically excited submicrometer scale cantilevers integrated with CMOS electronics. The devices have been calibrated obtaining an experimental sensitivity of 6×10-11g/cm2Hz equivalent to 0.9ag/Hz for locally deposited mass. Results from time-resolved mass measurements are also presented. An evaluation of the mass resolution have been performed obtaining a value of 2.4×10-17g in air conditions, resulting in an improvement of these devices from previous works in terms of sensitivity, resolution, and fabrication process complexity.

  19. Peroxy radicals and ozone photochemistry in air masses undergoing long-range transport

    NASA Astrophysics Data System (ADS)

    Parker, A. E.; Monks, P. S.; Jacob, M. J.; Penkett, S. A.; Lewis, A. C.; Stewart, D. J.; Whalley, L. K.; Methven, J.; Stohl, A.

    2009-09-01

    Concentrations of peroxy radicals (HO2+ΣiRiO2) in addition to other trace gases were measured onboard the UK Meteorological Office/Natural Environment Research Council British Aerospace 146-300 atmospheric research aircraft during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign based at Horta Airport, Faial, Azores (38.58° N, 28.72° W) in July/August 2004. The overall peroxy radical altitude profile displays an increase with altitude that is likely to have been impacted by the effects of long-range transport. The peroxy radical altitude profile for air classified as of marine origin shows no discernable altitude profile. A range of air-masses were intercepted with varying source signatures, including those with aged American and Asian signatures, air-masses of biomass burning origin, and those that originated from the east coast of the United States. Enhanced peroxy radical concentrations have been observed within this range of air-masses indicating that long-range transported air-masses traversing the Atlantic show significant photochemical activity. The net ozone production at clear sky limit is in general negative, and as such the summer mid-Atlantic troposphere is at limit net ozone destructive. However, there is clear evidence of positive ozone production even at clear sky limit within air masses undergoing long-range transport, and during ITOP especially between 5 and 5.5 km, which in the main corresponds to a flight that extensively sampled air with a biomass burning signature. Ozone production was NOx limited throughout ITOP, as evidenced by a good correlation (r2=0.72) between P(O3) and NO. Strong positive net ozone production has also been seen in varying source signature air-masses undergoing long-range transport, including but not limited to low-level export events, and export from the east coast of the United States.

  20. 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)

  1. Mass movements of lowland areas in long range TLS and ALS monitoring

    NASA Astrophysics Data System (ADS)

    Tyszkowski, Sebastian

    2015-04-01

    The development of geodynamic processes in lowland areas remains an interesting issue for geomorphology and geology as well as civil engineering. Landslides, slumps, slope washes, rills and gully erosion are considered both geomorphological processes and natural hazards. In order to know precisely their origin and development, it is crucial to determine the rate and direction of their change. Previously such studies used geodesy and photogrammetry but the recent progress in the LiDAR technology allows collecting the data in a wider range and comparable or higher precision than most of geodetic methods. Airborne Laser Scanning (ALS) is also a good tool, but high costs and low frequency of the surveys make it difficult to trace the dynamics of the studied phenomena and processes. Nevertheless, this method enables gathering information from large areas, which is useful for the preliminary identification of the research issues and nomination of the areas for subsequent case studies. It is, however, more common to use Terrestrial Laser Scanning (TLS) for the detailed studies of morphology and its change. This method provides mobility and high accuracy, and enables frequent measurements. The problem in the analysis of many geoprocesses lies in the limited range of this method. This study concerns the Lower Vistula Valley located in northern Poland. It presents the results of measurements of landslides located in the escarpment zone of a big river valley. The object of the studies is mass movements developing within the quaternary deposits on the valley slopes. These processes were monitored in previous years with the traditional survey methods, mainly based on the geodesy field observations (benchmark) as well as the analyses of historical maps and archives. The ALS method used during the study enabled gathering the data on the valley with the density of 8 points per sq m, which provided the background for the consecutive monitoring study. In the surveys a terrestrial

  2. 3. Mass Movements, Erosion Patterns and Sediment Transport along the Sutlej River (NW-Himalaya)

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Thiede, R. C.; Strecker, M. R.

    2003-04-01

    The spatial and temporal distribution of mass movements in active orogens can provide valuable insights into the relation between sedimentation and erosion processes. In areas of high relief, hillslope processes dominate surface geomorphology and can lead to the damming of rivers and formation of lakes upstream. These basins provide a record of natural climatic variations along the river profile and divide the regions in different sedimentational and erosional compartments. To characterize the variations, digital elevation models were used for quantitative analysis of topography, basin-fill volume, and active channel gradients. High-resolution spatial data (digitized 1:25,000 to 1:100,000 topographic maps) and ASTER-derived digital elevation models (DEM) were processed to analyze topography. Combined with geological field measurements and observations we could distinguish erosional patterns within several study areas in the NW Himalayas. Precipitation data were derived from calibrated passive microwave satellite data (SSMI), providing information on a 10 year time series at sufficient spatial resolution (12.5 km2). Modern sediment flux and transport, discharge, geomorphic field observations including river width and slope define the boundary conditions for surface erosion calculations. The Sutlej Valley (32N, 78E) in NW India is dominated by the antecedent Sutlej River, the third-largest river in the Himalayas. It flows perpendicular through the orogen and cuts through all major geologic units of the Tethyan Himalaya, High and Lesser Himalayan Crystallines, and Lower Himalayan units. The geomorphologic changes across thrust faults bounding these units provide valuable insights into the evolution of the orogen. Tectonically active sectors of the orogen are manifested by pronounced knickpoints in longitudinal river profiles that cross active thrust faults. In contrast to other parts of the Himalayas, no (re-) activation of the MCT and STDS can be seen in the

  3. r.randomwalk v1.0, a multi-functional conceptual tool for mass movement routing

    NASA Astrophysics Data System (ADS)

    Mergili, M.; Krenn, J.; Chu, H.-J.

    2015-09-01

    We introduce r.randomwalk, a flexible and multi-functional open source tool for backward- and forward-analyses of mass movement propagation. r.randomwalk builds on GRASS GIS, the R software for statistical computing and the programming languages Python and C. Using constrained random walks, mass points are routed from defined release pixels of one to many mass movements through a digital elevation model until a defined break criterion is reached. Compared to existing tools, the major innovative features of r.randomwalk are: (i) multiple break criteria can be combined to compute an impact indicator score, (ii) the uncertainties of break criteria can be included by performing multiple parallel computations with randomized parameter settings, resulting in an impact indicator index in the range 0-1, (iii) built-in functions for validation and visualization of the results are provided, (iv) observed landslides can be back-analyzed to derive the density distribution of the observed angles of reach. This distribution can be employed to compute impact probabilities for each pixel. Further, impact indicator scores and probabilities can be combined with release indicator scores or probabilities, and with exposure indicator scores. We demonstrate the key functionalities of r.randomwalk (i) for a single event, the Acheron Rock Avalanche in New Zealand, (ii) for landslides in a 61.5 km2 study area in the Kao Ping Watershed, Taiwan; and (iii) for lake outburst floods in a 2106 km2 area in the Gunt Valley, Tajikistan.

  4. A Synoptic Air Mass Approach to Defining Southwest U.S. Summer Duration and Change

    NASA Astrophysics Data System (ADS)

    Morrill, C.; Wachtel, C. J.; Godek, M. L.

    2015-12-01

    As the past decade was the warmest in the 110-year active record, and future Southwest warming is expected to be most intense in the summer season, it is important to have an updated atmospheric definition of what constitutes a Southwest summer. This is particularly true given the intensity of current drought conditions and that summers may be changing. Using weather-type data from the Spatial Synoptic Classification, this research aims to synoptically define the summer season in the Southwest since 1950. The Southwest is spatially described here by sub-region and 28 air mass stations within are chosen for air mass analysis. Daily air mass frequencies are examined to determine the dominant and less prevalent types annually and seasonally, from May to September. Then, frequencies in the middle of summer are compared to those in the seasonal fringe months to explore the possibility of a synoptic shift in the timing of the region's summer season. Finally, to further scrutinize how regional air mass frequencies have changed with time, the data are subdivided and evaluated for the 'Early record' (years prior to 1975) and 'Modern record' (post 1975). Frequency departures are tested for practical and statistical significance to characterize the strength of summer season variability. Results indicate that Dry Moderate air masses are the most common annually and in summer. Moist and transitional air masses tend to less frequent throughout the Southwest; however, frequencies vary greatly by sub-region. Wet and dry conditions are observed in accordance with the monsoon in some sub-regions, but not throughout the region. Significant changes in sub-regional air mass tendencies are identified that show the Early record experienced cooler air mass conditions (fewer tropical types and more moderate and cool types) than the Modern record. From a long-term synoptic air mass perspective, typical Southwest summers likely last from May to August. However, in the Modern record May

  5. Mass movement deposit and Tsunami in Lake Geneva (Switzerland-France) caused by a rockslide in 563 AD

    NASA Astrophysics Data System (ADS)

    Kremer, K.; Simpson, G.; Girardclos, S.

    2012-04-01

    Steep continental margins are known to collapse, producing submarine landslides that can generate Tsunamis. At smaller scale, the same can happen in lake basins. Lake sediments are excellent archives of such events. The study of mass movement deposits in lake sediments allows a better knowledge of past natural hazards in intracontinental regions at historic and prehistoric timescales. In Lake Geneva (Switzerland-France), more than 100 km of high resolution seismic reflection profiles reveal two distinct sequences in the lakes' late Holocene sedimentation history. The first sequence consists mainly of a succession of five large lens-shaped seismic units (A to E), characterized by transparent/chaotic seismic facies with irregular lower boundaries, interpreted as mass-movement deposits. These units are interbedded with parallel, continuous and strong amplitude reflections, interpreted as the 'background' lake sediment. The largest and most recent unit (E) is 5 m thick, covers an area of 50 km2 and has an estimated minimum volume of 0.25 km3, making it the largest sub-lacustrine mass-movement unit in Switzerland. The second sediment sequence consists of 5 m of 'background' seismic facies with parallel geometry, varying at small scale between chaotic/transparent and continuous, high amplitude reflections, which is interpreted as alternating turbidite and hemipelagic layers, respectively. Four 10 m long sediment cores confirm the seismic interpretation and show that the 5 m thick deposit can be described as a co-genetic debrite turbidite (Talling et al., 2004). Radiocarbon dating of plant macro-remains reveals that the unit E deposit may be linked to the Tauredunum rockslide of 563 AD in Rhone delta area. The induced sediment failure in the Rhone delta triggered a tsunami wave destroying parts of the Geneva Burgudian city and other villages at the lake borders as described in historical records. Numerical simulations, based on the shallow water equations, performed here

  6. 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

  7. 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.

  8. The effect of long-range air mass transport pathways on PM10 and NO2 concentrations at urban and rural background sites in Ireland: Quantification using clustering techniques.

    PubMed

    Donnelly, Aoife A; Broderick, Brian M; Misstear, Bruce D

    2015-01-01

    The specific aims of this paper are to: (i) quantify the effects of various long range transport pathways nitrogen dioxide (NO2) and particulate matter with diameter less than 10μm (PM10) concentrations in Ireland and identify air mass movement corridors which may lead to incidences poor air quality for application in forecasting; (ii) compare the effects of such pathways at various sites; (iii) assess pathways associated with a period of decreased air quality in Ireland. The origin of and the regions traversed by an air mass 96h prior to reaching a receptor is modelled and k-means clustering is applied to create air-mass groups. Significant differences in air pollution levels were found between air mass cluster types at urban and rural sites. It was found that easterly or recirculated air masses lead to higher NO2 and PM10 levels with average NO2 levels varying between 124% and 239% of the seasonal mean and average PM10 levels varying between 103% and 199% of the seasonal mean at urban and rural sites. Easterly air masses are more frequent during winter months leading to higher overall concentrations. The span in relative concentrations between air mass clusters is highest at the rural site indicating that regional factors are controlling concentration levels. The methods used in this paper could be applied to assist in modelling and forecasting air quality based on long range transport pathways and forecast meteorology without the requirement for detailed emissions data over a large regional domain or the use of computationally demanding modelling techniques.

  9. 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.

  10. Incidence of mass movement processes after an historical episode of heavy snowfall in the Asturian Massif (Northern Spain)

    NASA Astrophysics Data System (ADS)

    Garcia-Hernandez, Cristina; Ruiz-Fernández, Jesús; Gallinar, David

    2015-04-01

    This research examines a mass movement event caused in the context of the Great Blizzard of 1888, one of the most severe recorded blizzards in the history of Europe, whose implications go far beyond. In the Asturian Massif the episode consisted in four linked and consecutive snowstorms that took place between the 14th of February 1888 and the 8th of April 1888, creating snow covers with a depth ranging between 5 and 7 m, snow avalanches and flooding, causing dozens of deaths and large material damage. The Asturian Massif belongs to the Atlantic-climate area and is composed mainly by sedimentary and metamorphic paleozoic rocks. Many sectors of the Massif are between 1.000 and 2.000 m a.s.l., and its topography is characterized by a great height difference and steep slopes. Because of the lack of deep soils suitable for farming, the main traditional activity has been livestock keeping, and goods traffic. We have devised a method that enables the reconstruction of this event on the basis of nivo-meteorogical conditions, geographical location and socio-economic impact. The mass movement episode has been studied through the issues of 6 newspapers published in Asturias between the 20th of January and 30th of May 1888, the ancient meteorological station data of the University of Oviedo, and field work. A logical database structure has been designed with the aim to store and cross the information for statistical analysis. Thirty six mass movement worthy of consideration were documented, 28 of them causing material damage (six homes destroyed and at least 22 interruptions with the traffic flow on roads, highways and railways). Ten high- and mid-elevation mountain municipalities were affected by mass movement. We must consider that only the most important events, or those that happened in crowded places, have been considered by the newspapers, so the total number of mass movements should be considered as a minimum figure. We have got to identify and classify 27 of them; 16

  11. The correlation between movement of the center of mass and the kinematics of the spine, pelvis, and hip joints during body rotation.

    PubMed

    Wada, Osamu; Tateuchi, Hiroshige; Ichihashi, Noriaki

    2014-01-01

    Body rotation is associated with many activities. The concomitant movement of the center of mass (COM) is essential for effective body rotation. This movement is considered to be influenced by kinematic changes in the spine, pelvis, and hip joints. However, there is no research on the association between COM movement and kinematic changes during body rotation. We aimed to investigate the association between COM movement and the kinematics of the spine, pelvis, and hip joints during body rotation in standing. Twenty-four healthy men were included in the study. COM movement during active body rotation in a standing position was measured. We evaluated pelvic shift and changes in the angles of the spine, pelvis, and hip joints. We calculated the Pearson correlation coefficients to analyze the relationship between COM movement and kinematic changes in the spine, pelvis, and hip joints. There were significant correlations between lateral COM movement to the rotational side and pelvic shift to the rotational side, and between posterior COM movement and pelvic shift to the posterior side. In addition, lateral COM movement to the rotational side showed significant and negative correlation with spinal flexion and was significantly and positively correlated with the change in anterior pelvic tilt. Clinicians need to take particular note of both spinal and pelvic motion in the sagittal plane, as well as the pelvic shift, to speculate COM movement during body rotation in standing.

  12. Technical note: Air compared to nitrogen as nebulizing and drying gases for electrospray ionization mass spectrometry.

    PubMed

    Mielczarek, P; Silberring, J; Smoluch, M

    2016-01-01

    In the present study we tested the application of compressed air instead of pure nitrogen as the nebulizing and drying gas, and its influence on the quality of electrospray ionization (ESI) mass spectra. The intensities of the signals corresponding to protonated molecules were significantly (twice) higher when air was used. Inspection of signal-to-noise (S/N) ratios revealed that, in both cases, sensitivity was comparable. A higher ion abundance after the application of compressed air was followed by a higher background. Another potential risk of using air in the ESI source is the possibility for sample oxidation due to the presence of oxygen. To test this, we selected five easily oxidizing compounds to verify their susceptibility to oxidation. In particular, the presence of methionine was of interest. For all the compounds studied, no oxidation was observed. Amodiaquine oxidizes spontaneously in water solutions and its oxidized form can be detected a few hours after preparation. Direct comparison of the spectra where nitrogen was used with the corresponding spectra obtained when air was applied did not show significant differences. The only distinction was slightly different patterns of adducts when air was used. The difference concerns acetonitrile, which forms higher signals when air is the nebulizing gas. It is also important that the replacement of nitrogen with air does not affect quantitative data. The prepared calibration curves also visualize an intensity twice as high (independent of concentration within tested range) of the signal where air was applied. We have used our system continuously for three months with air as the nebulizing and drying gas and have not noticed any unexpected signal deterioration caused by additional source contamination from the air. Moreover, compressed air is much cheaper and easily available using oil-free compressors or pumps.

  13. Remote mass spectrometric sampling of electrospray- and desorption electrospray-generated ions using an air ejector.

    PubMed

    Dixon, R Brent; Bereman, Michael S; Muddiman, David C; Hawkridge, Adam M

    2007-10-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data are presented.

  14. A chain kinematic model to assess the movement of lower-limb including wobbling masses.

    PubMed

    Thouzé, A; Monnet, T; Bélaise, C; Lacouture, P; Begon, M

    2016-01-01

    Computer simulation models have shown that wobbling mass on the lower limb affects the joint kinetics. Our objective was to propose a non-invasive method to estimate bones and wobbling mass kinematics in the lower limb during hopping. The chain kinematic model has set degrees of freedom at the joints and free wobbling bodies. By comparison to a model without wobbling bodies, the marker residual was reduced by 20% but the joint kinematics remains unchanged. Wobbling bodies' displacements reached 6.9 ± 3.5° and 6.9 ± 2.4 mm relative to the modelled bones. This original method is a first step to assess wobbling mass effect on joint kinetics.

  15. Detection of Hydrazine in Air Using Electron Transfer Ionization Mass Spectrometry.

    DTIC Science & Technology

    1981-02-15

    is in tI qualitative agreement with American Petroleum Institute (API) 6 data. Unequivocal identification and monitoring of N2H4 fuels at the launch...N2H4 in air. At even lower concentrations, the delay time 61ndex of Mass Spectral Data, American Petroleum Institute , Research Project 44, NBS

  16. Toward a better understanding of the impact of mass transit air pollutants on human health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern mass transit systems, based on roads, rail, water, and air, generate toxic airborne pollutants throughout the developed world. This has become one of the leading concerns about the use of modern transportation, particularly in densely-populated urban areas where their use is enormous and inc...

  17. Modeling and hazard mapping of complex cascading mass movement processes: the case of glacier lake 513, Carhuaz, Peru

    NASA Astrophysics Data System (ADS)

    Schneider, Demian; Huggel, Christian; García, Javier; Ludeña, Sebastian; Cochachin, Alejo

    2013-04-01

    The Cordilleras in Peru are especially vulnerable to, and affected by impacts from climate change. Local communities and cities often exist directly within the reach of major hazard potentials such as lake outburst floods (aluviones), mud-/debris flows (huaycos) or large rock-/ice avalanches. They have been repeatedly and strongly affected these regions over the last decades and since the last century, and thousands of people have been killed. One of the most recent events in the Cordillera Blanca occurred on 11 April 2010, when a rock/ice avalanche from the top of Hualcán mountain, NE of the town of Carhuaz impacted the glacier lake 513 (Laguna 513), caused displacement waves and triggered an outburst flood wave. The flow repeatedly transformed from debris flow to hyperconcentrated flow and eventually caused significant damage in Carhuaz. This event was motivation to start early warning and prevention efforts to reduce risks related to ice/rock avalanches and glacier lake outburst floods (GLOF). One of the basic components of an early warning system is the assessment, understanding and communication of relevant hazards and risks. Here we report on the methodology and results of generating GLOF related hazard maps for Carhuaz based on numerical modeling and field work. This exercise required an advanced concept and implementation of different mass movement models. Specifically, numerical models were applied for simulating avalanche flow, avalanche lake impact, displacement wave generation and lake overtopping, and eventually flow propagation of the outburst flood with changing rheology between debris flow and hyperconcentrated flows. We adopted a hazard mapping procedure slightly adjusted adjusted from guidelines developed in Switzerland and in the Andes region. A methodology has thereby been developed to translate results from numerical mass movement modeling into hazard maps. The resulting hazard map was verified and adjusted during field work. This study shows

  18. Low-CCN concentration air masses over the eastern North Atlantic: Seasonality, meteorology, and drivers

    NASA Astrophysics Data System (ADS)

    Wood, Robert; Stemmler, Jayson D.; Rémillard, Jasmine; Jefferson, Anne

    2017-01-01

    A 20 month cloud condensation nucleus concentration (NCCN) data set from Graciosa Island (39°N, 28°W) in the remote North Atlantic is used to characterize air masses with low cloud condensation nuclei (CCN) concentrations. Low-CCN events are defined as 6 h periods with mean NCCN<20 cm-3 (0.1% supersaturation). A total of 47 low-CCN events are identified. Surface, satellite, and reanalysis data are used to explore the meteorological and cloud context for low-CCN air masses. Low-CCN events occur in all seasons, but their frequency was 3 times higher in December-May than during June-November. Composites show that many of the low-CCN events had a common meteorological basis that involves southerly low-level flow and rather low wind speeds at Graciosa. Anomalously low pressure is situated to the west of Graciosa during these events, but back trajectories and lagged SLP composites indicate that low-CCN air masses often originate as cold air outbreaks to the north and west of Graciosa. Low-CCN events were associated with low cloud droplet concentrations (Nd) at Graciosa, but liquid water path (LWP) during low-CCN events was not systematically different from that at other times. Satellite Nd and LWP estimates from MODIS collocated with Lagrangian back trajectories show systematically lower Nd and higher LWP several days prior to arrival at Graciosa, consistent with the hypothesis that observed low-CCN air masses are often formed by coalescence scavenging in thick warm clouds, often in cold air outbreaks.

  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. Radon as a tracer of daily, seasonal and spatial air movements in the Underground Tourist Route "Coal Mine" (SW Poland).

    PubMed

    Tchorz-Trzeciakiewicz, Dagmara Eulalia; Parkitny, Tomasz

    2015-11-01

    The surveys of radon concentrations in the Underground Tourist Route "Coal Mine" were carried out using passive and active measurement techniques. Passive methods with application of Solid State Nuclear Track Detectors LR115 were used at 4 points in years 2004-2007 and at 21 points in year 2011. These detectors were exchanged at the beginning of every season in order to get information about seasonal and spatial changes of radon concentrations. The average radon concentration noted in this facility was 799 Bq m(-3) and is consistent with radon concentrations noted in Polish coal mines. Seasonal variations, observed in this underground tourist route, were as follows: the highest radon concentrations were noted during summers, the lowest during winters, during springs and autumns intermediate but higher in spring than in autumn. The main external factor that affected seasonal changes of radon concentrations was the seasonal variation of outside temperature. No correlation between seasonal variations of radon concentrations and seasonal average atmospheric pressures was found. Spatial variations of radon concentrations corresponded with air movements inside the Underground Tourist Route "Coal Mine". The most vivid air movements were noted along the main tunnel in adit and at the place located near no blinded (in the upper part) shaft. Daily variations of radon concentrations were recorded in May 2012 using RadStar RS-230 as the active measurement technique. Typical daily variations of radon concentrations followed the pattern that the highest radon concentrations were recorded from 8-9 a.m. to 7-8 p.m. and the lowest during nights. The main factor responsible for hourly variations of radon concentrations was the daily variation of outside temperatures. No correlations were found between radon concentration and other meteorological parameters such as atmospheric pressure, wind velocity or precipitation. Additionally, the influence of human factor on radon

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. [The investigation of control mechanisms of stepping rhythm in human in the air-stepping conditions during passive and voluntary leg movements].

    PubMed

    Solopova, I A; Selionon, V A; Grishin, A A

    2010-01-01

    influences from moving leg in the most degree then on central commands. It seems that afferent inputs from pressure receptors of foot in the condition of "air-stepping" actively interact with central program of stepping and, irrespective of type of the performing movements (voluntary or passive), form the final pattern activity.

  6. 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

  7. Source areas and trajectories of nucleating air masses within and near the Carpathian Basin

    NASA Astrophysics Data System (ADS)

    Németh, Z.; Salma, I.

    2014-04-01

    Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6-1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeast Central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28+6/-4) % and (27+9/-4) %, respectively. Total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate if there are any specific tracks and/or separable source regions for the nucleating air masses within or near the basin. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation, and end time parameter of the particle growth were derived by a standardized procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each air mass trajectory that is associated with the track of the nucleating air mass. The results indicated that the nucleation events happened in the continental boundary layer mostly within the Carpathian Basin but the most distant trajectories originated outside of the basin. The tracks of the nucleating air masses were predominantly associated with NW and SE geographical fields, while the source areas that could be separated were frequently situated in the NW and NE quarters. Many of them were within or close to large forested territories. The results also emphasize that the new particle formation and growth phenomenon that occurs in the region influences larger territories than the Carpathian Basin.

  8. Seasonal air and water mass redistribution effects on LAGEOS and Starlette

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roberto; Wilson, Clark R.

    1987-01-01

    Zonal geopotential coefficients have been computed from average seasonal variations in global air and water mass distribution. These coefficients are used to predict the seasonal variations of LAGEOS' and Starlette's orbital node, the node residual, and the seasonal variation in the 3rd degree zonal coefficient for Starlette. A comparison of these predictions with the observed values indicates that air pressure and, to a lesser extent, water storage may be responsible for a large portion of the currently unmodeled variation in the earth's gravity field.

  9. Improving Hydrological Models by Applying Air Mass Boundary Identification in a Precipitation Phase Determination Scheme

    NASA Astrophysics Data System (ADS)

    Feiccabrino, James; Lundberg, Angela; Sandström, Nils

    2013-04-01

    Many hydrological models determine precipitation phase using surface weather station data. However, there are a declining number of augmented weather stations reporting manually observed precipitation phases, and a large number of automated observing systems (AOS) which do not report precipitation phase. Automated precipitation phase determination suffers from low accuracy in the precipitation phase transition zone (PPTZ), i.e. temperature range -1° C to 5° C where rain, snow and mixed precipitation is possible. Therefore, it is valuable to revisit surface based precipitation phase determination schemes (PPDS) while manual verification is still widely available. Hydrological and meteorological approaches to PPDS are vastly different. Most hydrological models apply surface meteorological data into one of two main PPDS approaches. The first is a single rain/snow threshold temperature (TRS), the second uses a formula to describe how mixed precipitation phase changes between the threshold temperatures TS (below this temperature all precipitation is considered snow) and TR (above this temperature all precipitation is considered rain). However, both approaches ignore the effect of lower tropospheric conditions on surface precipitation phase. An alternative could be to apply a meteorological approach in a hydrological model. Many meteorological approaches rely on weather balloon data to determine initial precipitation phase, and latent heat transfer for the melting or freezing of precipitation falling through the lower troposphere. These approaches can improve hydrological PPDS, but would require additional input data. Therefore, it would be beneficial to link expected lower tropospheric conditions to AOS data already used by the model. In a single air mass, rising air can be assumed to cool at a steady rate due to a decrease in atmospheric pressure. When two air masses meet, warm air is forced to ascend the more dense cold air. This causes a thin sharp warming (frontal

  10. 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 ...

  11. Mixing of stratospheric and tropospheric air-masses detected with CRISTA-NF during AMMA

    NASA Astrophysics Data System (ADS)

    Weigel, K.; Guenther, G.; Hoffmann, L.; Konopka, P.; Riese, M.

    2009-04-01

    CRISTA-NF (CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere - New Frontiers) is an infrared limb sounding instrument installed onbord the high-flying research aircraft M55-Geophysica and took part in the AMMA-SCOUT measurement campaign in Summer 2006. During the test flight on 29th of July 2006, CRISTA-NF detected a sharp boundary between ozone rich air over northernItaly and ozone poor air over southern Italy and the Mediterranean Sea. The structure is also clearly visible in the HNO3 distribution. The air mass boundary extends from about 10km altitude to the thermal tropopause at about 16km altitude with indication for mixing in the lower part of this altitude range. This is supported by enhanced values of PAN and water vapour found. The observed structure is also visible in the CLaMS (Chemical Lagrangian Model of the Stratosphere) ozone distribution but hardly resolved in ECMWF forecast data. Backward trajectories show that the ozone rich air is originated westwards, between 40 and 60oN while the ozone poor air is coming from the south-east, at about 0-20oN and has a younger age of air. In the presentation details of the CRISTA-NF measurements and retrieval procedures as well as the origin of the trace gas structures will be discussed.

  12. Shear-strength signatures of mass movements, continental slope of Campos Basin, Brazil

    NASA Astrophysics Data System (ADS)

    Kowsmann, R. O.; da Costa, A. M.; Amaral, C. S.

    2003-04-01

    Downhole shear-strength profiles, obtained from cone-penetrometer and lab tests were tied to sedimentary facies from adjacent continuous cores. The geotechnical response of mass-transport deposits was investigated. In the Campos Basin, sediments have evacuated from the upper continental slope and have accumulated as folded deposits on the middle slope. Sediment removal is recognised by an abrupt step-like increase in shear-strength at the level of the unconformity. The folded deposits are characterised by a belly-shaped increase in shear-strength coinciding with a zone of intense lamination within the deposit, induced by internal shearing and fluid loss (strain hardening). In contrast, highly disintegrated muddy debris-flow deposits are indistinguishable, in terms of shear-strength, from normal hemipelagic slope sediments. Debris-flow tongues emanating from canyon mouths, which contain a significant amount of more consolidated mud clasts can however be differentiated from in situ sediments by their serrated signature and higher shear-strength.

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

    2012-04-01

    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 in order to study aerosol physical, chemical and optical properties, as well as cloud microphysics. During the campaign, continental air masses from Eastern and Western Europe were encountered, along with polar and Scandinavian air masses. 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 which allows for a qualitative evaluation of emission influence on the respective air parcel. In the polluted boundary layer (BL), typical concentrations of particles with diameters larger than 10 nm (N10) are of the order of 5000-6000 cm-3, whereas N10 concentrations of clean air masses were lower than 1300 cm-3. The detection of the largest particle number concentrations occurred in air masses coming from Polar and Scandinavian regions for which an elevated number of nucleation mode (25-28 nm) particles was observed and attributed to new particle formation over open sea. In the free troposphere (FT), typical observed N10 are of the order of 900 cm-3 in polluted air masses and 400-600 cm-3 in clean air masses, respectively. In both layers, the chemical composition of submicron aerosol particles is dominated by organic matter and nitrate in polluted air masses, while, sulphate and ammonium followed by organics dominate the submicron aerosols in clean air masses. The highest CCN/CN ratios were observed within the polar air masses while the CCN concentration values are the highest within the polluted air masses. Within the five air mass sectors defined and the two layers (BL and FT), observations have been distinguished into anticyclonic (first half of May 2008) and cyclonic

  14. Enhancement of acidic gases in biomass burning impacted air masses over Canada

    NASA Technical Reports Server (NTRS)

    Lefer, B. L.; Talbot, R. W.; Harriss, R. C.; Bradshaw, J. D.; Sandholm, S. T.; Olson, J. O.; Sachse, G. W.; Collins, J.; Shipham, M. A.; Blake, D. R.

    1994-01-01

    Biomass-burning impacted air masses sampled over central and eastern Canada during the summer of 1990 as part of ABLE 3B contained enhanced mixing ratios of gaseous HNO3, HCOOH, CH3COOH, and what appears to be (COOH)2. These aircraft-based samples were collected from a variety of fresh burning plumes and more aged haze layers from different source regions. Values of the enhancement factor, delta X/delta CO, where X represents an acidic gas, for combustion-impacted air masses sampled both near and farther away from the fires, were relatively uniform. However, comparison of carboxylic acid emission ratios measured in laboratory fires to field plume enhancement factors indicates significant in-plume production of HCOOH. Biomass-burning appears to be an important source of HNO3, HCOOH, and CH3COOH to the troposphere over subarctic Canada.

  15. Ozone and Trace Gas Trends in the UK and Links to Changing Air Mass Pathways

    NASA Astrophysics Data System (ADS)

    Fleming, Z.; Monks, P. S.; Reeves, C.; Bohnenstengel, S.

    2014-12-01

    Trace gas measurements from UK measurement sites on the North Sea coast and in central London reveal a complicated relationship between NO2, CO, hydrocarbons and ozone. Due to the location of the sites, they receive air masses from the UK, Europe, the North sea, Scandinavia and the Arctic and Atlantic Seas and any seasonality is hard to discern. The transport pathway of air masses that can change on an hourly timescale clearly influences the trace gas levels. Investigations into how the transport pathways have changed over the years, using the NAME dispersion model try to elucidate whether it is the 'where' (transport pathway) or the 'what' (trace gas emissions) that is leading to the ozone trends recorded over the past few years.

  16. Toward a better understanding of the impact of mass transit air pollutants on human health.

    PubMed

    Kim, Ki-Hyun; Kumar, Pawan; Szulejko, Jan E; Adelodun, Adedeji A; Junaid, Muhammad Faisal; Uchimiya, Minori; Chambers, Scott

    2017-05-01

    Globally, modern mass transport systems whether by road, rail, water, or air generate airborne pollutants in both developing and developed nations. Air pollution is the primary human health concern originating from modern transportation, particularly in densely-populated urban areas. This review will specifically focus on the origin and the health impacts of carbonaceous traffic-related air pollutants (TRAP), including particulate matter (PM), volatile organic compounds (VOCs), and elemental carbon (EC). We conclude that the greatest current challenge regarding urban TRAP is understanding and evaluating the human health impacts well enough to set appropriate pollution control measures. Furthermore, we provide a detailed discussion regarding the effects of TRAP on local environments and pedestrian health in low and high traffic-density environments.

  17. 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.

  18. 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).

  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.

    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.

  1. 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.

  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 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

  4. 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

  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. 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.

  7. Large mass movements, probably earthquake triggered, in Lake Geneva off the city of Lausanne revealed by seismic and sediment coring data

    NASA Astrophysics Data System (ADS)

    Correia Demand, Jehanne; Marillier, François; Yrro, Blé; Kremer, Katrina; Girardclos, Stéphanie

    2013-04-01

    Recent seismic studies in the central part of Lake Geneva have revealed the presence a series of Holocene sedimentary layers with either well-organized reflections or with chaotic or transparent seismic character. While the former correspond to lacustrine sediments deposited as hemipelagic or turbidite layers, the latter are interpreted to be related to mass movements. One of these events has recently been identified in the lake off the city of Lausanne. The total volume of the mass flow deposits, the surface of the associated turbidite and the length of its failure scar show that it was a major slide event. To study this lacustrine slide, two types of seismic data were acquired. The first one was a multichannel system with a 15 inch3 water gun with a central frequency of 800 Hz and the second one was a 3.5 kHz single channel pinger. The data sets provide complementary data, because of their differing vertical resolution, respectively 0.5 m and 0.15 m. Some data were acquired with both systems along the same profiles for direct comparison. A depth-age relationship derived from a sediment core located above the main mass deposit yields an age for the mass movement deposit between 3488 and 3820 cal BP (2 sigma uncertainty). The failure scar that lies close to the lake north shore appears to be continuous over a distance of more than 7 km. However, the presence of two separated mass flow deposits associated with this scar suggests that there were in fact two simultaneous slides and not only one. This, together with the observation of another simultaneous mass movement on the lake south shore of the lake, suggests that the mass movements were triggered by an earthquake. The mass movements off the city of Lausanne are located over a major fault zone affecting the Mesozoic substratum under the Quaternary sediments. The fault zone which is related to the formation of the Alps is not known to be seismically active at present. However, conspicuous features within the

  8. The mass movement routing tool r.randomwalk and its functionalities for parameter sensitivity analysis and optimization

    NASA Astrophysics Data System (ADS)

    Krenn, Julia; Mergili, Martin

    2016-04-01

    r.randomwalk is a GIS-based, multi-functional conceptual tool for mass movement routing. Starting from one to many release points or release areas, mass points are routed down through the digital elevation model until a defined break criterion is reached. Break criteria are defined by the user and may consist in an angle of reach or a related parameter (empirical-statistical relationships), in the drop of the flow velocity to zero (two-parameter friction model), or in the exceedance of a maximum runup height. Multiple break criteria may be combined. A constrained random walk approach is applied for the routing procedure, where the slope and the perpetuation of the flow direction determine the probability of the flow to move in a certain direction. r.randomwalk is implemented as a raster module of the GRASS GIS software and, as such, is open source. It can be obtained from http://www.mergili.at/randomwalk.html. Besides other innovative functionalities, r.randomwalk serves with built-in functionalities for the derivation of an impact indicator index (III) map with values in the range 0-1. III is derived from multiple model runs with different combinations of input parameters varied in a random or controlled way. It represents the fraction of model runs predicting an impact at a given pixel and is evaluated against the observed impact area through an ROC Plot. The related tool r.ranger facilitates the automated generation and evaluation of many III maps from a variety of sets of parameter combinations. We employ r.randomwalk and r.ranger for parameter optimization and sensitivity analysis. Thereby we do not focus on parameter values, but - accounting for the uncertainty inherent in all parameters - on parameter ranges. In this sense, we demonstrate two strategies for parameter sensitivity analysis and optimization. We avoid to (i) use one-at-a-time parameter testing which would fail to account for interdependencies of the parameters, and (ii) to explore all possible

  9. Mass movements in the Rio Grande Valley (Quebrada de Humahuaca, Northwestern Argentina): a methodological approach to reduce the risk

    NASA Astrophysics Data System (ADS)

    Marcato, G.; Pasuto, A.; Rivelli, F. R.

    2009-10-01

    Slope processes such as slides and debris flows, are among the main events that induce effects on the Rio Grande sediment transport capacity. The slides mainly affect the slope of the Rio Grande river basin while debris and mud flows phenomena take place in the tributary valleys. In the past decades several mass movements occurred causing victims and great damages to roads and villages and therefore hazard assessment and risk mitigation is of paramount importance for a correct development of the area. This is also an urgent need since the Quebrada de Humahuaca was recently included in the UNESCO World Cultural Heritage. The growing tourism business may lead to an uncontrolled urbanization of the valley with the consequent enlargement of threatened areas. In this framework mitigation measures have to take into account not only technical aspects related to the physical behaviour of the moving masses but also environmental and sociological factors that could influence the effectiveness of the countermeasures. Mitigation of landslide effects is indeed rather complex because of the large extension of the territory and the particular geological and geomorphological setting. Moreover the necessity to maintain the natural condition of the area as prescribed by UNESCO, make this task even more difficult. Nowadays no in-depth study of the entire area exists, therefore an integrated and multidisciplinary investigation plan is going to be set up including geological and geomorphological investigations as well as archaeological and historical surveys. The better understanding of geomorphological evolution processes of the Quebrada de Humahuaca will bridge the gap between the necessity of preservation and the request of safety keeping of the recommendation by UNESCO.

  10. 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

  11. Influence of air mass origin on aerosol properties at a remote Michigan forest site

    NASA Astrophysics Data System (ADS)

    VanReken, T. M.; Mwaniki, G. R.; Wallace, H. W.; Pressley, S. N.; Erickson, M. H.; Jobson, B. T.; Lamb, B. K.

    2015-04-01

    The northern Great Lakes region of North America is a large, relatively pristine area. To date, there has only been limited study of the atmospheric aerosol in this region. During summer 2009, a detailed characterization of the atmospheric aerosol was conducted at the University of Michigan Biological Station (UMBS) as part of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX). Measurements included particle size distribution, water-soluble composition, and CCN activity. Aerosol properties were strongly dependent on the origin of the air masses reaching the site. For ∼60% of the study period, air was transported from sparsely populated regions to the northwest. During these times aerosol loadings were low, with mean number and volume concentrations of 1630 cm-3 and 1.91 μm3 cm-3, respectively. The aerosol during clean periods was dominated by organics, and exhibited low hygroscopicities (mean κ = 0.18 at s = 0.3%). When air was from more populated regions to the east and south (∼29% of the time), aerosol properties reflected a stronger anthropogenic influence, with 85% greater particle number concentrations, 2.5 times greater aerosol volume, six times more sulfate mass, and increased hygroscopicity (mean k = 0.24 at s = 0.3%). These trends are have the potential to influence forest-atmosphere interactions and should be targeted for future study.

  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. Calibration of Dissolved Noble Gas Mass Spectrometric Measurements by an Air-Water Equilibration System

    NASA Astrophysics Data System (ADS)

    Hillegonds, Darren; Matsumoto, Takuya; Jaklitsch, Manfred; Han, Liang-Feng; Klaus, Philipp; Wassenaar, Leonard; Aggarwal, Pradeep

    2013-04-01

    Precise measurements by mass spectrometry of dissolved noble gases (He, Ar, Ne, Kr, Xe) in water samples require careful calibration against laboratory standards with known concentrations. Currently, air pipettes are used for day-to-day calibrations, making estimation of overall analytical uncertainties for dissolved noble gas measurements in water difficult. Air equilibrated water (AEW) is often used as a matrix-equivalent laboratory standard for dissolved gases in groundwater, because of the well-known and constant fractions of noble gases in the atmosphere. AEW standards, however, are only useful if the temperature and pressure of the gas-water equilibrium can be controlled and measured precisely (i.e., to better than 0.5%); contamination and partial sample degassing must also be prevented during sampling. Here we present the details of a new custom air-water equilibration system which consists of an insulated 600 liter tank filled with deionized water, held isothermally at a precise target temperature (<0.05 °C) through the use of a heat exchanger. The temperature and total dissolved gas of the water in the tank are monitored continually, as are atmospheric pressure and air temperature in the laboratory. Different noble gas concentration standards can be reliably produced by accurately controlling the water temperature of the equilibration system. Equilibration characteristics and reproducibility of this system for production of copper tubes containing known amounts of noble gases will be presented.

  14. Determination of the effect of transfer between vacuum and air on mass standards of platinum-iridium and stainless steel

    NASA Astrophysics Data System (ADS)

    Davidson, Stuart

    2010-08-01

    This paper reports work undertaken to assess the change in the mass values of stainless steel and platinum-iridium weights transferred between air and vacuum and to determine the repeatability of this change. Sets of kilogram transfer standards, manufactured from stainless steel and platinum-iridium and with different surface areas, were used to determine the effect of transfer between air and vacuum on the values of the mass standards. The SI unit of mass is the only unit of the seven base SI quantities which is still defined in terms of an artefact rather than by relation to a fundamental physical constant. Work is underway to identify a means of deriving the SI unit of mass from fundamental constants and at present the two principal approaches are the International Avogadro Coordination and the watt balance projects. Both of these approaches involve realizing a kilogram in vacuum and therefore the traceability from a kilogram realized in vacuum to mass standards in air is crucial to the effective dissemination of the mass scale. The work reported here characterizes the changes in mass values of standards on transfer between air and vacuum and thus will enable traceability to be established for an in-air mass scale based on a definition of the unit in vacuum.

  15. Effect of the relative optical air mass and the clearness index on solar erythemal UV irradiance.

    PubMed

    Moreno, J C; Serrano, M A; Cañada, J; Gurrea, G; Utrillas, M P

    2014-09-05

    This paper analyses the effects of the clearness index (Kt) and the relative optical air mass (mr) on erythemal UV irradiance (UVER). The UVER measurements were made in Valencia (Spain) from 6:00 am to 6:00 pm between June 2003 and December 2012 and (140,000 data points). Firstly, two models were used to calculate values for the erythemal ultraviolet irradiance clearness index (KtUVER) as a function of the global irradiance clearness index (Kt). Secondly, a potential regression model to measure the KtUVER as a function of the relative optical air mass was studied. The coefficients of this regression were evaluated for clear and cloudy days, as well as for days with high and low ozone levels. Thirdly, an analysis was made of the relationship between the two effects in the experimental database, with it being found that the highest degree of agreement, or the joint highest frequencies, are located in the optical mass range mr∈[1.0, 1.2] and the clearness index range of Kt∈[0.8, 1.0]. This is useful for establishing the ranges of parameters where models are more efficient. Simple equations have been tested that can provide additional information for the engineering projects concerning thermal installations. Fourthly, a high dispersion of radiation data was observed for intermediate values of the clearness for UV and UVER.

  16. Visual Steering and Verification of Mass Spectrometry Data Factorization in Air Quality Research.

    PubMed

    Engel, D; Greff, K; Garth, C; Bein, K; Wexler, A; Hamann, B; Hagen, H

    2012-12-01

    The study of aerosol composition for air quality research involves the analysis of high-dimensional single particle mass spectrometry data. We describe, apply, and evaluate a novel interactive visual framework for dimensionality reduction of such data. Our framework is based on non-negative matrix factorization with specifically defined regularization terms that aid in resolving mass spectrum ambiguity. Thereby, visualization assumes a key role in providing insight into and allowing to actively control a heretofore elusive data processing step, and thus enabling rapid analysis meaningful to domain scientists. In extending existing black box schemes, we explore design choices for visualizing, interacting with, and steering the factorization process to produce physically meaningful results. A domain-expert evaluation of our system performed by the air quality research experts involved in this effort has shown that our method and prototype admits the finding of unambiguous and physically correct lower-dimensional basis transformations of mass spectrometry data at significantly increased speed and a higher degree of ease.

  17. The relationship of force output characteristics during a sit-to-stand movement with lower limb muscle mass and knee joint extension in the elderly.

    PubMed

    Yamada, Takayoshi; Demura, Shinichi

    2010-01-01

    This study examined the reliability of ground reaction force (GRF) parameters during sit-to-stand (STS) movements and the relationships between the GRF parameters and lower limb muscle mass and knee extension muscle strength. Fifty elderly females performed an STS movement twice from a chair adjusted to their knee height and the GRF, lower limb muscle mass and isometric knee extension muscle strength were measured. Reliabilities of GRF parameters were high (intra-class correlation coefficient=ICC=0.70-0.95). Parameters on force output during trunk flexion phase (ground reaction force at hip-lift off, sum of force output between beginning of STS movement and hip-lift off) differed significantly between trials, but their effect sizes were small (0.15-0.23). GRF parameters during hip-lift off and knee-hip joint extension phases significantly correlated with knee extension strength (|r|=0.29-0.64) but not lower limb muscle mass. In conclusion, the reliability of GRF during STS movement is good in hip-lift off and knee-hip joint extension phases and these phases relate significantly with lower limb muscle function. These two phases are useful for evaluation of leg muscle function of the elderly.

  18. Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Shirley, John A.; Winter, Michael

    1993-01-01

    An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

  19. Ozone Modulation/Membrane Introduction Mass Spectrometry for Analysis of Hydrocarbon Pollutants in Air

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.

    2001-12-01

    Modulation of volatile hydrocarbons in two-component mixtures is demonstrated using an ozonolysis pretreatment with membrane introduction mass spectrometry (MIMS). The MIMS technique allows selective introduction of volatile and semivolatile analytes into a mass spectrometer via processes known collectively as pervaporation [Kotiaho and Cooks, 1992]. A semipermeable polymer membrane acts as an interface between the sample (vapor or solution) and the vacuum of the mass spectrometer. This technique has been demonstrated to allow for sensitive analysis of hydrocarbons and other non-polar volatile organic compounds (VOC`s) in air samples[Cisper et al., 1995] . The methodology has the advantages of no sample pretreatment and short analysis time, which are promising for online monitoring applications but the chief disadvantage of lack of a separation step for the different analytes in a mixture. Several approaches have been investigated to overcome this problem including use of selective chemical ionization [Bier and Cooks, 1987] and multivariate calibration techniques[Ketola et al., 1999] . A new approach is reported for the quantitative measurement of VOCs in complex matrices. The method seeks to reduce the complexity of mass spectra observed in hydrocarbon mixture analysis by selective pretreatment of the analyte mixture. In the current investigation, the rapid reaction of ozone with alkenes is used, producing oxygenated compounds which are suppressed by the MIMS system. This has the effect of removing signals due to unsaturated analytes from the compound mass spectra, and comparison of the spectra before and after the ozone treatment reveals the nature of the parent compounds. In preliminary investigations, ozone reacted completely with cyclohexene from a mixture of cylohexene and cyclohexane, and with β -pinene from a mixture of toluene and β -pinene, suppressing the ion signals from the olefins. A slight attenuation of the cyclohexane and toluene in those

  20. 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.

  1. Relationship between functional movement screen scores, core strength, posture, and body mass index in school children in Moldova.

    PubMed

    Mitchell, Ulrike H; Johnson, A Wayne; Adamson, Brynn

    2015-05-01

    The assessment of functionality should include parameters that consider postural control, limb asymmetries, range of motion limitations, proprioceptive deficits, and pain. An increasingly popular battery of tests, the Functional Movement Screen (FMS), is purported to assess the above named parameters. The purpose of our study was twofold: (a) to report differences in total FMS scores in children, provide preliminary normative reference values of each of the 7 individual FMS scores for both genders and report on asymmetries and (b) to evaluate the relationship between total FMS scores, age, body mass index (BMI), core strength/stability, and postural angles to explore the possibility of using the FMS in the assessment of children's functional fitness. Descriptive data on 77 children aged 8-11 years were collected. The children performed core strength/stability exercises. Photographs were taken from a lateral view for later calculation of postural angles. The children performed the FMS while being videotaped for later review. The average total FMS score (of 21) was 14.9 (+1.9), and BMI was 16.4 (+2.2). Static posture is not related to results of the FMS. Core strength was positively correlated to the total FMS score (r = 0.31; p = 0.006). Over 60% demonstrated at least 1 asymmetry. The individual test scores indicate that none of the test items is too difficult for the children. Based on the screen's correlation to core strength, and the fact that it identifies areas of asymmetry, we suggest to further investigate its possible use in the assessment of children's functional fitness.

  2. VOC Composition of Air Masses Transported from Asia to the U.S. West Coast

    NASA Astrophysics Data System (ADS)

    de Gouw, J.; Warneke, C.; Kuster, B.; Parrish, D.; Holloway, J.; Huebler, G.; Fehsenfeld, F.

    2002-12-01

    Airborne measurements of volatile organic compounds (VOCs) were performed using a proton-transfer-reaction mass spectrometer (PTR-MS) operated onboard a NOAA WP-3 aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in 2002. Enhancements of acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN) and in some cases benzene were observed in air masses that were impacted by outflow from Asia. The enhancement ratios with respect to carbon monoxide are compared to emission factors for fossil fuel combustion and biomass burning, which gives some insight into the sources responsible for the pollution. The observed mixing ratios for acetone, methanol and in particular acetonitrile were generally reduced in the marine boundary layer, suggesting the presence of an ocean uptake sink. The ocean uptake of acetonitrile was found to be particularly efficient in a zone with upwelling water off of the U.S. west coast. Reduced mixing ratios of acetone and methanol were observed in a stratospheric intrusion. This observation gives some information about the lifetime of these VOCs in the stratosphere. Enhanced concentrations of aromatic hydrocarbons were observed in air masses that were impacted by urban sources in California. The ratio between the concentrations of benzene, toluene and higher aromatics indicated the degree of photochemical oxidation. PTR-MS only gives information about the mass of the ions produced by proton-transfer reactions between H3O+ and VOCs in the instrument. The identification of VOCs was confirmed by coupling a gas-chromatographic (GC) column to the instrument and post-flight GC-PTR-MS analyses of canister samples collected during the flights.

  3. Air mass characterization during the DAURE field campaign by PTR-TOF

    NASA Astrophysics Data System (ADS)

    Metzger, Axel; Schallhart, Simon; Müller, Markus; Hansel, Armin

    2010-05-01

    Volatile organic compounds (VOCs) are emitted into the atmosphere from a wide variety of biogenic and anthropogenic sources. Although some of the sources are well characterized, many uncertainties remain about the fate of these compounds in the atmosphere and their role in organic aerosol formation. Here we present measurements using Proton Transfer Reaction Time-of-Flight (PTR-TOF) Mass Spectrometry during the DAURE field campaign ("Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean") obtained during February and March 2009. Measurements were performed at a rural mountain site located in the Montseny Natural Park 40 km to the NNE of the city of Barcelona, and 25 km from the Mediterranean coast. Volatile organic compounds where identified and quantified using PTR-TOF with 1 minute time resolution. The instruments mass resolving power of 4000 - 5000 and a mass accuracy of 5 ppm allows for the unambiguous sum-formula identification of e.g. hydrocarbons (HCs) or oxygenated VOCs (OVOCs). The high time resolution allows separating out on site pollution events. Air masses impacted by biomass-burning, urban, marine and vegetation emissions are characterized using tracers like acetonitrile, aromatics, dimethyl sulfide or biogenic compounds (terpenoids) and the degree of photochemical processing is inferred from the data.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Use of stable lead isotopes and trace metals to characterize air mass sources into the eastern North Atlantic

    NASA Astrophysics Data System (ADS)

    VéRon, Alain J.; Church, Thomas M.

    1997-12-01

    Stable lead isotopes (204Pb, 206Pb, 207Pb, 208Pb) and trace metals (Mn, Al, Fe, Ni, Cu, Cd, Zn, Pb) have been analyzed in aerosol collected during the Atlantic Stratocumulus Transition Experiment-Marine Aerosol and Gas Exchange (ASTEX-MAGE) cruise that transited between Miami and the Azores from May to July 1992. Our goal was to define the continental signatures of the air masses encountered between the Azores and the subtropical regions. The combination of air mass trajectories, trace metal concentrations and stable lead isotopes allowed us to characterize the anthropogenic character of encountered air masses. The average 206Pb/207Pb ratio was 1.148±0.021 and corresponded to a mixing between well defined European (such as Great Britain with 1.115<206Pb/207Pb<1.125 and France with 206Pb/207Pb=1.141±0.000) and North American sources (with 206Pb/207Pb=1.184±0.000). On the basis of air mass trajectories and trace metal concentrations, the background isotopic signature associated with the trade winds (206Pb/207Pb=1.161±0.004) is consistent with previous reports by Church et al. [1990] such as 206Pb/207Pb=1.154±0.004 in 1988, (Véron et al., 1993), 206Pb/207Pb=1.155±0.004 in 1989, and Hamelin et al. [1996] (206Pb/207Pb=1.158±0.006) in 1991. Short-term variations of continental air mass sources was particularly investigated by considering the anthropogenic character of aerosols collected during two Lagrangian experiments conducted as part of the ASTEX-MAGE cruise. We demonstrated the utility of stable lead isotopes to assign a "continental source signature" (or mixture thereof) to air masses beyond that normally possible by conventional air mass trajectory analysis in remote oceanic regions.

  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.

  10. Aerosols in polluted versus nonpolluted air masses Long-range transport and effects on clouds

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    To assess the influence of anthropogenic aerosols on the physics and chemistry of clouds in the northeastern United States, 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, NY, 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 of 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. (2) A significant fraction of anthropogenic sulfur appears to act as cloud condensation nuclei (CCN) to affect the cloud drop concentration. (3) 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. (4) 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.

  11. 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.

  12. An effective indicator of continental scale cold air outbreaks in northern winter: the intensity variation of the meridional mass circulation

    NASA Astrophysics Data System (ADS)

    Ren, R.; Yu, Y.; Cai, M.

    2015-12-01

    This study reports that the intensity variation of the meridional mass circulation can be an effective leading indicator of cold air outbreaks (CAOs) over midlatitudes in northern winter. It is found that continental-scale coldness by cold air outbreaks (CAOs) tend to preferentially occur within a week after stronger mass circulation events defined as the peak time when the net mass transport across 60°N in the upper warm or the lower cold air branch exceeds ~88×109 kg s-1. During weaker mass circulation events when the net mass transport across 60°N is below ~71.6×109 kg s-1, most areas of the mid-latitudes are generally in mild condition except the northern part of Western Europe. Composite pattern of circulation anomalies during stronger mass circulation events greatly resemble that of the winter-mean, with the two main routes of anomalous cold air outbreaks being along the climatological routes of polar cold air, namely, via East Asia and North America. The Siberian High shifts westward during stronger mass circulation events, opening up a third route of cold air outbreaks through Eastern Europe. The relationship of CAOs with Arctic Oscillation (AO) is less robust because temporal changes of AO are resulted from a small imbalance between the poleward and equatorward branches of the mass circulation. Only when the poleward branch leads the equatorward branch (44% of all cases), CAOs tend to take place within a week after a negative phase of AO. The daily ERA-Interim reanalysis data set for the 32 winters in 1979-2011 were used in this study.

  13. 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.

  14. Air mass modification over Europe: EARLINET aerosol observations from Wales to Belarus

    NASA Astrophysics Data System (ADS)

    Wandinger, Ulla; Mattis, Ina; Tesche, Matthias; Ansmann, Albert; BöSenberg, Jens; Chaikovski, Anatoly; Freudenthaler, Volker; Komguem, Leonce; Linné, Holger; Matthias, Volker; Pelon, Jacques; Sauvage, Laurent; Sobolewski, Piotr; Vaughan, Geraint; Wiegner, Matthias

    2004-12-01

    For the first time, the vertically resolved aerosol optical properties of western and central/eastern European haze are investigated as a function of air mass transport. Special emphasis is put on clean maritime air masses that cross the European continent from the west and become increasingly polluted on their way into the continent. The study is based on observations at seven lidar stations (Aberystwyth, Paris, Hamburg, Munich, Leipzig, Belsk, and Minsk) of the European Aerosol Research Lidar Network (EARLINET) and on backward trajectory analysis. For the first time, a lidar network monitored continent-scale haze air masses for several years (since 2000). Height profiles of the particle backscatter coefficient and the particle optical depth of the planetary boundary layer (PBL) at 355-nm wavelength are analyzed for the period from May 2000 to November 2002. From the observations at Aberystwyth, Wales, the aerosol reference profile for air entering Europe from pristine environments was determined. A mean 355-nm optical depth of 0.05 and a mean PBL height of 1.5 km was found for clean maritime summer conditions. The particle optical depth and PBL height increased with increasing distance from the North Atlantic. Mean summer PBL heights were 1.9-2.8 km at the continental sites of Leipzig, Belsk, and Minsk. Winter mean PBL heights were mostly between 0.7 and 1.3 km over the seven EARLINET sites. Summer mean 355-nm optical depths increased from 0.17 (Hamburg, northwesterly airflow from the North Sea) and 0.21 (Paris, westerly flow from the Atlantic) over 0.33 (Hamburg, westerly flow) and 0.35 (Leipzig, westerly flow) to 0.59 (Belsk, westerly flow), and decreased again to 0.37 (westerly flow) at Minsk. Winter mean optical depths were, on average, 10-30% lower than the respective summer values. PBL-mean extinction coefficients were of the order of 200 Mm-1 at 355 nm at Hamburg and Leipzig, Germany, and close to 600 Mm-1 at Belsk, Poland, in winter for westerly flows

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. The influence of polarization on box air mass factors for UV/vis nadir satellite observations

    NASA Astrophysics Data System (ADS)

    Hilboll, Andreas; Richter, Andreas; Rozanov, Vladimir V.; Burrows, John P.

    2015-04-01

    Tropospheric abundances of pollutant trace gases like, e.g., NO2, are often derived by applying the differential optical absorption spectroscopy (DOAS) method to space-borne measurements of back-scattered and reflected solar radiation. The resulting quantity, the slant column density (SCD), subsequently has to be converted to more easily interpretable vertical column densities by means of the so-called box air mass factor (BAMF). The BAMF describes the ratio of SCD and VCD within one atmospheric layer and is calculated by a radiative transfer model. Current operational and scientific data products of satellite-derived trace gas VCDs do not include the effect of polarization in their radiative transfer models. However, the various scattering processes in the atmosphere do lead to a distinctive polarization pattern of the observed Earthshine spectra. This study investigates the influence of these polarization patterns on box air mass factors for satellite nadir DOAS measurements of NO2 in the UV/vis wavelength region. NO2 BAMFs have been simulated for a multitude of viewing geometries, surface albedos, and surface altitudes, using the radiative transfer model SCIATRAN. The results show a potentially large influence of polarization on the BAMF, which can reach 10% and more close to the surface. A simple correction for this effect seems not to be feasible, as it strongly depends on the specific measurement scenario and can lead to both high and low biases of the resulting NO2 VCD. We therefore conclude that all data products of NO2 VCDs derived from space-borne DOAS measurements should include polarization effects in their radiative transfer model calculations, or at least include the errors introduced by using linear models in their uncertainty estimates.

  20. 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.

  1. A Comparison of Two Methods for Initiating Air Mass Back Trajectories

    NASA Astrophysics Data System (ADS)

    Putman, A.; Posmentier, E. S.; Faiia, A. M.; Sonder, L. J.; Feng, X.

    2014-12-01

    Lagrangian air mass tracking programs in back cast mode are a powerful tool for estimating the water vapor source of precipitation events. The altitudes above the precipitation site where particle's back trajectories begin influences the source estimation. We assume that precipitation comes from water vapor in condensing regions of the air column, so particles are placed in proportion to an estimated condensation profile. We compare two methods for estimating where condensation occurs and the resulting evaporation sites for 63 events at Barrow, AK. The first method (M1) uses measurements from a 35 GHz vertically resolved cloud radar (MMCR), and algorithms developed by Zhao and Garrett1 to calculate precipitation rate. The second method (M2) uses the Global Data Assimilation System reanalysis data in a lofting model. We assess how accurately M2, developed for global coverage, will perform in absence of direct cloud observations. Results from the two methods are statistically similar. The mean particle height estimated by M2 is, on average, 695 m (s.d. = 1800 m) higher than M1. The corresponding average vapor source estimated by M2 is 1.5⁰ (s.d. = 5.4⁰) south of M1. In addition, vapor sources for M2 relative to M1 have ocean surface temperatures averaging 1.1⁰C (s.d. = 3.5⁰C) warmer, and reported ocean surface relative humidities 0.31% (s.d. = 6.1%) drier. All biases except the latter are statistically significant (p = 0.02 for each). Results were skewed by events where M2 estimated very high altitudes of condensation. When M2 produced an average particle height less than 5000 m (89% of events), M2 estimated mean particle heights 76 m (s.d. = 741 m) higher than M1, corresponding to a vapor source 0.54⁰ (s.d. = 4.2⁰) south of M1. The ocean surface at the vapor source was an average of 0.35⁰C (s.d. = 2.35⁰C) warmer and ocean surface relative humidities were 0.02% (s.d. = 5.5%) wetter. None of the biases was statistically significant. If the vapor source

  2. 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.

  3. Large-scale transport of a CO-enhanced air mass from Europe to the Middle East

    NASA Technical Reports Server (NTRS)

    Connors, V. S.; Miles, T.; Reichle, H. G., Jr.

    1989-01-01

    On November 14, 1981, the shuttle-borne Measurement of Air Pollution from Satellites (MAPS) experiment observed a carbon monoxide (CO) enhanced air mass in the middle troposphere over the Middle East. The primary source of this polluted air was estimated by constructing adiabatic isentropic trajectories backwards from the MAPS measurement location over a 36 h period. The isentropic diagnostics indicate that CO-enhanced air was transported southeastward over the Mediterranean from an organized synoptic-scale weather regime, albeit of moderate intensity, influencing central Europe on November 12. Examination of the evolving synoptic scale vertical velocity and precipitation patterns during this period, in conjuction with Meteosat visible, infrared, and water vapor imagery, suggests that the presence of this disturbed weather system over Europe may have created upward transport of CO-enhanced air between the boundary-layer and midtropospheric levels, and subsequent entrainment in the large-scale northwesterly jet stream flow over Europe and the Mediterranean.

  4. 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.

  5. Air/water subchannel measurements of the equilibrium quality and mass-flux distribution in a rod bundle. [BWR

    SciTech Connect

    Sterner, R.W.; Lahey, R.T. Jr.

    1983-07-01

    Subchannel measurements were performed in order to determine the equilibrium quality and mass flux distribution in a four rod bundle, using air/water flow. An isokinetic technique was used to sample the flow in the center, side and corner subchannels of this test section. Flow rates of the air and water in each sampled subchannel were measured. Experiments were performed for two test-section-average mass fluxes (0.333x10/sup 6/ and 0.666x10/sup 6/ lb/sub m//h-ft/sup 2/), and the test-section-average quality was varied from 0% to 0.54% for each mass flux. Single-phase liquid, bubbly, slug and churn-turbulent two-phase flow regimes were achieved. The observed data trends agreed with previous diabatic measurements in which the center subchannel had the highest quality and mass flux, while the corner subchannel had the lowest.

  6. Lake dwellers occupation gap in Lake Geneva (France-Switzerland) possibly explained by an earthquake-mass movement-tsunami event during Early Bronze Age

    NASA Astrophysics Data System (ADS)

    Kremer, Katrina; Marillier, François; Hilbe, Michael; Simpson, Guy; Dupuy, David; Yrro, Ble J. F.; Rachoud-Schneider, Anne-Marie; Corboud, Pierre; Bellwald, Benjamin; Wildi, Walter; Girardclos, Stéphanie

    2014-01-01

    High-resolution seismic and sediment core data from the ‘Grand Lac’ basin of Lake Geneva reveal traces of repeated slope instabilities with one main slide-evolved mass-flow (minimum volume 0.13 km3) that originated from the northern lateral slope of the lake near the city of Lausanne. Radiocarbon dating of organic remains sampled from the top of the main deposit gives an age interval of 1865-1608 BC. This date coincides with the age interval for a mass movement event described in the ‘Petit Lac’ basin of Lake Geneva (1872-1622 BC). Because multiple mass movements took place at the same time in different parts of the lake, we consider the most likely trigger mechanism to be a strong earthquake (Mw 6) that occurred in the period between 1872 and 1608 BC. Based on numerical simulations, we show the major deposit near Lausanne would have generated a tsunami with local wave heights of up to 6 m. The combined effects of the earthquake and the following tsunami provide a possible explanation for a gap in lake dwellers occupation along the shores of Lake Geneva revealed by dendrochronological dating of two palafitte archaeological sites.

  7. Seismically-induced mass movements and volumetric fluxes resulting from the 2010 Mw = 7.2 earthquake in the Sierra Cucapah, Mexico

    NASA Astrophysics Data System (ADS)

    Barlow, John; Barisin, Ivana; Rosser, Nick; Petley, David; Densmore, Alexander; Wright, Tim

    2015-02-01

    The observation that sediment flux from mountain ranges struck by high magnitude earthquakes can be strongly influenced by coseismic mass movements brings into question the nature of coseismic deformation as a net contributor to mountain building. To better constrain the role of high-magnitude earthquakes in orogenesis, high-resolution data of earthquake induced mass wasting is required for areas of differing tectonic, morphological, and climatic settings. Here we compare the erosional flux to the tectonic flux associated with the 2010 Mw = 7.2 Sierra El Mayor earthquake in Mexico and examine the landslide patterning of coseismic mass movements associated with this event. The ruptured fault system has a significant strike-slip component with subsidence along the eastern flank and uplift on the western flank of the range. Peak ground acceleration was highest along the steepest sections of the range such that the frequency of landslide occurrence was strongly correlated to slope gradient. Both vertical and horizontal coseismic displacement demonstrated a strong control over landslide initiation. This result suggests that strike-slip systems experience very different landslide patterning to thrust faults during earthquakes. Based on interferometric analysis of synthetic aperture radar images, the earthquake resulted in a total uplifted volume of 41.6 × 106 m3 and a loss of 95.2 × 106 m3 due to subsidence. This suggests a net tectonic volumetric flux of - 53.6 × 106 m3. Sediment mobilisation by coseismic landslides is estimated at - 2.7 × 106 m3 derived from a manually mapped inventory using SPOT 5 multispectral imagery. Thus, the net volume loss through coseismic subsidence of the mountain range generated a strongly negative mass flux, which was only marginally enhanced by mass wasting.

  8. Movement Disorders

    MedlinePlus

    ... t want them to. If you have a movement disorder, you experience these kinds of impaired movement. Dyskinesia ... movement and is a common symptom of many movement disorders. Tremors are a type of dyskinesia. Nerve diseases ...

  9. Optimization of solar cells for air mass zero operation and a study of solar cells at high temperatures, phase 3

    NASA Technical Reports Server (NTRS)

    Blakeslee, A. E.; Hovel, H. J.; Woodall, J. M.

    1977-01-01

    The etch-back epitaxy process is described for producing thin, graded composition GaAlAs layers. The palladium-aluminum contact system is discussed along with its associated problems. Recent solar cell results under simulated air mass zero light and at elevated temperatures are reported and the growth of thin polycrystalline GaAs films on foreign substrates is developed.

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

    PubMed

    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.

  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. 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.

  13. Northern East Asian Monsoon Precipitation Revealed by Air Mass Variability and Its Prediction

    NASA Astrophysics Data System (ADS)

    Son, J. H.; Seo, K. H.

    2015-12-01

    This work provides a new perspective on the major factors controlling the East Asian summer monsoon (EASM) in July, and a promising physical-statistical forecasting of the EASM ahead of summer. Dominant modes of the EASM are revealed from the variability of large-scale air masses discerned by equivalent potential temperature, and are found to be dynamically connected with the anomalous sea surface temperatures (SSTs) over the three major oceans of the world and their counterparts of prevailing atmospheric oscillation or teleconnection patterns. Precipitation over Northeast Asia (NEA) during July is enhanced by the tropical central Indian Ocean warming and central Pacific El Niño-related SST warming, the northwestern Pacific cooling off the coast of NEA, and the North Atlantic Ocean warming. Using these factors and data from the preceding spring seasons, the authors build a multiple linear regression model for seasonal forecasting. The cross-validated correlation skill predicted for the period 1994 to 2012 is up to 0.84, which far exceeds the skill level of contemporary climate models.

  14. Inverse Estimation of SO2 Emissions over China with Local Air Mass Factor Applied

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wang, J.; Xu, X.; Henze, D. K.

    2015-12-01

    Sulfur dioxide (SO2) has significant impacts on human health as it forms sulfate aerosols in the atmosphere. Widespread uncertainty in the magnitude of SO2 emissions hinders efforts to address this issue. In this work we use Ozone Monitoring Instrument (OMI) slant column SO2 observations as constraints to conduct inversion of SO2 emissions over China for April 2008. Local air mass factors are formulated as the integral of the relative vertical distribution of SO2 simulated from GEOS-Chem, weighted by scattering weights computed from VLIDORT. They are applied to convert slant column to vertical column GEOS-Chem SO2. After data assimilation SO2 emissions decrease in Sichuan Basin, South China, and most areas of North China. The posterior SO2 emissions are evaluated with in situ SO2 observation. Besides, we apply the posterior SO2 emissions of April 2008 to April 2009, and it leads to improved agreement of modeled SO2 to the OMI observations. This offers potential to update SO2 emissions in real time.

  15. Anticipatory control of center of mass and joint stability during voluntary arm movement from a standing posture: interplay between active and passive control.

    PubMed

    Patla, Aftab E; Ishac, Milad G; Winter, David A

    2002-04-01

    Anticipatory control of upright posture is the focus of this study that combines experimental and modeling work. Individuals were asked to raise or lower their arms from two initial postures such that the final posture of the arm was at 90 degrees with respect to the body. Holding different weights in the hand varied the magnitude of perturbation to postural stability generated by the arm movement. Whole body kinematics and ground reaction forces were measured. Inverse dynamic analysis was used to determine the internal joint moments at the shoulder, hip, knee and ankle, and reaction forces at the shoulder. Center of mass (COM) of the arm, posture (rest of the body without the arms) and whole body (net COM) were also determined. Changes in joint moment at the hip, knee and ankle revealed a significant effect of the direction of movement. The polarities of the joint moment response were appropriate for joint stabilization. Net COM change showed a systematic effect of the direction of movement even though the arm COM was displaced by the same amount and in the same direction for both arm raising and lowering conditions. In order to determine the effects of the passive forces and moments on the posture COM, the body was modeled as an inverted pendulum. The model was customized for each participant; the relevant model parameters were estimated from data obtained from each trial. The ankle joint stiffness and viscosity were adjusted to ensure postural equilibrium prior to arm movement. Joint reactive forces and moments generated by the arm movements were applied at the shoulder level of this inverted pendulum; these were the only inputs and no active control was included. The posture COM profile from the model simulation was calculated. Results show that simulated posture COM profile and measured posture COM profile are identical for about 200 ms following the onset of arm movement and then they deviate. Therefore, the initial control of COM is passive in nature and the

  16. 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

  17. Geomorphology of Late Quaternary Mass Movement Deposits using a Decimetre-Resolution 3D Seismic Volume: Case Studies from Windermere, UK, and Trondheimsfjorden, Norway

    NASA Astrophysics Data System (ADS)

    Vardy, M. E.; Dix, J. K.; Henstock, T.; Bull, J. M.; Pinson, L.; L'Heureux, J.; Longva, O.; Hansen, L.; Chand, S.; Gutowski, M.

    2009-12-01

    We present results from decimetre resolution 3D seismic volumes acquired over Late Quaternary mass movement deposits in both Lake Windermere, UK, and the Trondheim Harbour area, central Norway. Both deposits were imaged using the 3D Chirp sub-bottom profiler, which combines the known, highly repeatable source waveform of Chirp profilers with the coherent processing and interpretation afforded by true 3D seismic volumes. Reflector morphology from these two volumes are used to identify and map structure on scales of 10s cm to 100s metres. This shows the applicability of the method for the interpretation of failure mechanism, flow morphology and depositional style in these two environments. In Windermere, Younger Dryas deposits have been substantially reworked by the episodic redistribution of sediment from the steep lakesides into the basin. Within the 100 x 400 m 3D seismic volume we identify two small debris flow deposits (1500 m3 and 60,000 m3) and one large (500,000 m3) erosive mass flow deposit. These two depositional mechanisms are distinct. The debris flows have high amplitude, chaotic internal reflections, with a high amplitude reflector representing a lower erosional boundary, discontinuous low amplitude top reflector, and thin out rapidly with distance from the lake margin. The thicker mass flow unit lacks internal structure, and has high amplitude top and base reflectors,. In the Trondheim Harbour we image the down-slope extent of three large slide blocks (which have a net volume > 1 x 106 m3), mobilised by a landslide in 1990, in the 100 x 450 m 3D seismic volume. The morphology of these mass movement deposits is distinct again; demonstrating translational failure along a clear slip plane, leaving well defined slide scars, and forming prominent compressional/extensional structures.

  18. Gazing into Thin Air: The Dual-Task Costs of Movement Planning and Execution during Adaptive Gait

    PubMed Central

    Ellmers, Toby J.; Cocks, Adam J.; Doumas, Michail; Williams, A. Mark; Young, William R.

    2016-01-01

    We examined the effect of increased cognitive load on visual search behavior and measures of gait performance during locomotion. Also, we investigated how personality traits, specifically the propensity to consciously control or monitor movements (trait movement ‘reinvestment’), impacted the ability to maintain effective gaze under conditions of cognitive load. Healthy young adults traversed a novel adaptive walking path while performing a secondary serial subtraction task. Performance was assessed using correct responses to the cognitive task, gaze behavior, stepping accuracy, and time to complete the walking task. When walking while simultaneously carrying out the secondary serial subtraction task, participants visually fixated on task-irrelevant areas ‘outside’ the walking path more often and for longer durations of time, and fixated on task-relevant areas ‘inside’ the walkway for shorter durations. These changes were most pronounced in high-trait-reinvesters. We speculate that reinvestment-related processes placed an additional cognitive demand upon working memory. These increased task-irrelevant ‘outside’ fixations were accompanied by slower completion rates on the walking task and greater gross stepping errors. Findings suggest that attention is important for the maintenance of effective gaze behaviors, supporting previous claims that the maladaptive changes in visual search observed in high-risk older adults may be a consequence of inefficiencies in attentional processing. Identifying the underlying attentional processes that disrupt effective gaze behaviour during locomotion is an essential step in the development of rehabilitation, with this information allowing for the emergence of interventions that reduce the risk of falling. PMID:27824937

  19. A Cross-Age Study of Pupils' Conceptions Concerning the Movement of Air Masses in the Troposphere.

    ERIC Educational Resources Information Center

    Papadimitriou, Vasiliki; Londridou, Paraskevi

    Since weather plays an important role in many ways in our everyday life, the study of meteorological phenomena by school children becomes of great importance in enhancing their scientific literacy. This necessity becomes even more important today, as these phenomena are connected to serious environmental problems such as climate change and air…

  20. Literacy Education and Social Change Efforts in Pre-Communist China: The Mass Education Movement 1922-1949.

    ERIC Educational Resources Information Center

    Paulston, Rolland G.

    Socioeconomic development in China between the two world wars included an extensive mass education effort by reform-minded young Chinese. Focusing on adult literacy and rural reconstruction, Chinese educators employed various strategies to stimulate and assist self-help efforts in Chinese villages. Paramount among these educational techniques were…

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

    SciTech Connect

    Morrison, Glenn Charles

    1999-12-01

    -7, 10-5, and 10-5 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 10-5, 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.

  2. Change of microbial communities in glaciers along a transition of air masses in western China

    NASA Astrophysics Data System (ADS)

    Xiang, Shu-Rong; Chen, Yong; Shang, Tian-Cui; Jing, Ze-Fan; Wu, Guangjian

    2010-12-01

    Microbial community dynamics across glaciers in different climatic zones provide important information about the sources, transportation pathways, and deposition of microorganisms. To better understand the possible driving forces of microbial community shifts in glacier ice at a large spatial scale, 16S rRNA gene amplification was used to establish clone libraries containing 95 bacterial sequences from three different habitats in the Qiangyong Gacier in 2005. The libraries were used in phylogenetic comparison with 149 previously reported sequences from the surface samples collected from the Kuytun 51, and East Rongbuk glaciers in the same year. The results showed the presence of cosmopolitan and endemic species, and displayed a tendency of zonal distribution of bacterial communities at genera and community levels, corresponding to the geographic placement of the three glaciers. Data also showed a significant difference in the proportion of dominant phylogenetic groups in the three glaciers. Comamonadaceae/Polaromonas (Betaproteobacteria) and Flexibacteraceae (Bacteroidetes) were dominant in the Qiangyong Glacier, Cyanobacteria, Comamonadaceae/Polaromonas, and Rhodoferax (Betaproteobacteria) were dominant in the Kuytun 51 Glacier, and Acinetobacteria (Gammaproteobacteria) were dominant in the Rongbuk Glacier. In conclusion, the current study provides evidence of microbial biogeography in glacier ice at both the fine lineage and whole community levels. The biogeographical patterns were generally associated with the hydrological transition over the glaciers in the northern periphery and southern part of the Tibetan plateau. This supports our hypothesis of air mass behavior being one of the main drivers determining the zonal distribution of microbial communities across the mountain glaciers in western China.

  3. Climatology of wintertime long-distance transport of surface-layer air masses arriving urban Beijing in 2001-2012

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xiang-De, XU

    2017-02-01

    In this study, the FLEXPART-WRF coupled modeling system is used to conduct 12-year Lagrangian modeling over Beijing, China, for the winters of 2001-2012. Based on large trajectory tracking ensembles, the long-range air transport properties, in terms of geographic source regions within the atmospheric planetary boundary layer (PBL) and large-scale ventilation, and its association with air quality levels were quantified from a climatological perspective. The results show the following: (1) The air masses residing in the near-surface layer over Beijing potentially originate from broader atmospheric boundary-layer regions, which cover vast areas with the backward tracking time elapsed. However, atmospheric transport from northeastern China and, to a lesser extent, from the surrounding regions of Beijing is important. (2) The evolution of air quality over Beijing is negatively correlated with large-scale ventilation conditions, particularly at a synoptic timescale. Thus, the simple but robust backward-trajectory ventilation (BV) index defined in this study could facilitate operational forecasting of severe air pollution events. (3) By comparison, the relatively short-range transport occurring over transport timescales of less than 3 days from southern and southeastern Beijing and its surrounding areas plays a vital role in the formation of severe air pollution events during the wintertime. (4) Additionally, an interannual trend analysis suggests that the geographic sources and ventilation conditions also changed, at least over the last decade, corresponding to the strength variability of the winter East Asian monsoon.

  4. Regional hydro-meteorological thresholds for shallow and deep-seated mass movements triggering in the South Eastern French Alps (Queyras, Ubaye, Mercantour)

    NASA Astrophysics Data System (ADS)

    Remaitre, Alexandre; Malet, Jean-Philippe; Rigoudy, Gaëlle

    2015-04-01

    Rainfall is recognized worldwide as the main triggering factor of landslides. Numerous studies were conducted in order to (1) define qualitatively the relationships between the precipitations and the triggering or the reactivation of landslides and (2) determine quantitatively the amount of precipitation needed to trigger slopes failures. For rainfall-induced landslides, hydro-meteorological thresholds (expressed in terms of antecedent rain, intensity of the precipitation, soil moisture or ground water levels within the slope) can be defined as the rainfall, soil moisture or hydrological conditions that, when reached or exceeded, are likely to trigger landslides. Usually, the thresholds are based on the analysis of statistical relations among historical landslide catalogues (event dates) and antecedent hydro-meteorological conditions; other approaches based on conceptual or process-based models can also be used in specific cases such as limited information in landslide catalogues. Further, both the large variety of landslide types and the extreme variability of climatic conditions in mountain regions limit the definition of regional relationships between landslide occurrence and the associated hydro-meteorological conditions. The purpose of this work is to propose hydro-meteorological thresholds for the triggering of shallow (slides, debris/mud flows) and deep-seated mass movements for three mountainous massifs regions of the Southeast French Alps (Queyras, Mercantour, Ubaye) characterized by different rainfall patterns. For this purpose, we exploit for each study sites an historical landslide catalogue and rainfall data series to define a typology of rainfall induced-landslides for the relevant landslide types. For the analysis of the triggering of the deep-seated mass movements, slope hydrological time series (ground water levels, soil moisture) and simple water balance models are used to define hydrological thresholds for landslide reactivation. The results of

  5. Study of the Tropospheric Aerosol Structure Under Changing of the Air Mass Type from Lidar Observations in Tomsk

    NASA Astrophysics Data System (ADS)

    Samoilova, S. V.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. É.

    2016-04-01

    The aerosol optical characteristics in the main tropospheric layers are investigated based on joint interpretation of data of multi-frequency lidar sensing (110 sessions) and results of modeling of back air mass trajectories. Methodical problems for separating layers with different scattering properties and estimating their vertical boundaries are considered. Three optical criteria are simultaneously used to distinguish aerosol layers from cloud formations, including the gradient of the backscattering coefficient, optical depth, and the depolarization ratio. High values of the lidar ratio (66 sr) and of the Angstrom exponent (1.62) in the shortwavelength spectral range are observed in the boundary layer for Arctic transport. At the same time, low values of these optical parameters are characteristic for Asian transport: the lidar ratio is 54 sr and the Angstrom exponent is 1.1, which is explained by different relative contributions of the coarse and fine aerosol fractions to the air mass.

  6. Simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters by gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Akyüz, Mehmet

    2008-05-01

    A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters (PMs). The method includes collection of the particulate matters (PM2.5 and PM10) using dichotomous Partisol 2025 sampler followed by extraction of the compounds into acidic solution, and pre-concentration of the compounds by percolating the air samples through the acidic solution, then ion-pair extraction of amines with bis-2-ethylhexylphosphate and derivatisation with isobutyl chloroformate prior to their GC-MS analysis in both electron impact and positive and negative ion chemical ionisation mode as their isobutyloxycarbonyl (isoBOC) derivatives. In the present study, ambient air and airborne particulate samples collected in Zonguldak province during summer and winter times of 2006-2007 were analysed for aliphatic and aromatic amines by the proposed method and the method was shown to be suitable for the simultaneous determination of these compounds at the levels of pg m-3 in air and airborne particulate samples. The seasonal distributions of bioactive amines in concentrations in ambient air and airborne PMs were evaluated as they are significant for the estimation of their effects on the environment and human health. The concentration levels of water soluble amines fluctuate significantly within a year with higher means and peak concentrations, probably due to the increased emissions from coal-fired domestic and central heating, in the winter times compared to the summer times. The results indicated that the relative amine content in particulates modulates with molecular mass and time of the year and the relative amine content especially in fine fractions of inhalable airborne particulates increases with the molecular mass of species but decreases with temperature.

  7. Calculations of relative optical air masses for various aerosol types and minor gases in Arctic and Antarctic atmospheres

    NASA Astrophysics Data System (ADS)

    Tomasi, Claudio; Petkov, Boyan H.

    2014-02-01

    The dependence functions of relative optical air mass on apparent solar zenith angle θ have been calculated over the θ < 87° range for the vertical profiles of wet-air molecular number density in the Arctic and Antarctic atmospheres, extinction coefficients of different aerosol types, and molecular number density of water vapor, ozone, nitrogen dioxide, and oxygen dimer. The calculations were made using as weight functions the seasonal average vertical profiles of (i) pressure and temperature derived from multiyear sets of radiosounding measurements performed at Ny-Ålesund, Alert, Mario Zucchelli, and Neumayer stations; (ii) volume extinction coefficients of background summer aerosol, Arctic haze, and Kasatochi and Pinatubo volcanic aerosol measured with lidars or balloon-borne samplings; and (iii) molecular number concentrations of the above minor gases, derived from radiosonde, ozonesonde, and satellite-based observations. The air mass values were determined using a formula based on a realistic atmospheric air-refraction model. They were systematically checked by comparing their mutual differences with the uncertainties arising from the seasonal and daily variations in pressure and temperature conditions within the various ranges, where aerosol and gases attenuate the solar radiation most efficiently. The results provide evidence that secant-approximated and midlatitude air mass values are inappropriate for analyzing the Sun photometer measurements performed at polar sites. They indicate that the present evaluations can be reliably used to estimate the aerosol optical depth from the Arctic and Antarctic measurements of total optical depth, after appropriate corrections for the Rayleigh scattering and gaseous absorption optical depths.

  8. Screening for sarin in air and water by solid-phase microextraction-gas chromatography-mass spectrometry.

    PubMed

    Schneider, J F; Boparai, A S; Reed, L L

    2001-10-01

    A method of screening air and water samples for the chemical-warfare agent Sarin is developed using solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). The SPME field kit sampler is ideal for collecting air and water samples in the field and transporting samples safely to the laboratory. The sampler also allows the sample to be introduced into the GC-MS system without further sample preparation. Results of the tests with Sarin using the SPME technique indicate that a sample collection time of 5 min is sufficient to detect 100 ng/L of Sarin in air. For water samples, Sarin is detected at a concentration of 12 microg/mL or higher. This method is ideal for screening samples for quick response situations.

  9. Screening for sarin in air and water by solid-phase microextraction-gas chromatography/mass spectrometry.

    SciTech Connect

    Schneider, J. F.; Boparai, A. S.; Reed, L. L.

    2001-10-01

    A method of screening air and water samples for the chemical-warfare agent Sarin is developed using solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). The SPME field kit sampler is ideal for collecting air and water samples in the field and transporting samples safely to the laboratory. The sampler also allows the sample to be introduced into the GC-MS system without further sample preparation. Results of the tests with Sarin using the SPME technique indicate that a sample collection time of 5 min is sufficient to detect 100 ng/L of Sarin in air. For water samples, Sarin is detected at a concentration of 12 {mu}g/mL or higher. This method is ideal for screening samples for quick response situations.

  10. 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.

  11. Sex pheromones of Callosobruchus subinnotatus and C. maculatus (Coleoptera: Bruchidae): congeneric responses and role of air movement.

    PubMed

    Mbata, G N; Shu, S; Ramaswamy, S B

    2000-04-01

    Females of Callosobruchus spp. are known to produce sex pheromones that attract males. These sex pheromones cannot be adopted for use in pest management without first investigating the responses of the males in the windless conditions of storage environments. Consequently, behavioural bioassays of Callosobruchus subinnotatus Pic males were conducted in an olfactometer in the absence of air-flow. Under these conditions males were found to be able to follow odour trails to the source. However, the latency period was longer in diffusional bioassays than for insects in a Y-tube olfactometer that provided directional wind cues. The highest percentage of males reached the pheromone source when components of the pheromones, (E)-3-methyl-2-heptenoic acid (E32A) and (Z)-3-methyl-2-heptenoic acid (Z32A), were formulated in a 50:50 or 25:75 ratio. Males of C. maculatus (Fabricius) responded to sex pheromone of C. subinnotatus, but males of C. subinnotatus did not respond to that of C. maculatus. The two sex pheromone components of C. subinnotatus are also constituents of C. maculatus sex pheromone. These two components may be potentially useful in monitoring the populations of both species in stored beans. It is postulated that (Z)-3-methyl-3-heptenoic acid (Z33A), the major component of the sex pheromone of C. maculatus, must have acted as an antagonist inhibiting response of C. subinnotatus to the sex pheromone of C. maculatus.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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 Astrophysics Data System (ADS)

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

    2013-10-01

    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 (λ = 550 nm) 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 sulfate, nitrate, and elemental carbon. Achieving full optical closure is hampered by limitations in accounting for the role of water vapor in the system, uncertainties in the instruments and the need for further knowledge in the source apportionment of the model's major chemical components. Nonetheless, 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 sulfate 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. Consistency between the measured and modeled optical parameters serves as an

  17. 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

  18. New air Cherenkov light detectors to study mass composition of cosmic rays with energies above knee region

    NASA Astrophysics Data System (ADS)

    Tsunesada, Yoshiki; Katsuya, Ryoichi; Mitsumori, Yu; Nakayama, Keisuke; Kakimoto, Fumio; Tokuno, Hisao; Tajima, Norio; Miranda, Pedro; Salinas, Juan; Tavera, Wilfredo

    2014-11-01

    We have installed a hybrid detection system for air showers generated by cosmic rays with energies greater than 3 ×1015 eV at Mount Chacaltaya (5200 m above the sea level), in order to study the mass composition of cosmic rays above the knee region. This detection system comprises an air shower array with 49 scintillation counters in an area of 500 m×650 m, and seven new Cherenkov light detectors installed in a radial direction from the center of the air shower array with a separation of 50 m. It is known that the longitudinal development of a particle cascade in the atmosphere strongly depends on the type of the primary nucleus, and an air shower initiated by a heavier nucleus develops faster than that by a lighter primary of the same energy, because of the differences in the interaction cross-section and the energy per nucleon. This can be measured by detecting the Cherenkov radiation emitted from charged particles in air showers at higher altitudes. In this paper we describe the design and performance of our new non-imaging Cherenkov light detectors at Mount Chacaltaya that are operated in conjunction with the air shower array. The arrival directions and energies of air showers are determined by the shower array, and information about the primary masses is obtained from the Cherenkov light data including the time profiles and lateral distributions. The detector consists of photomultiplier tube (PMT), high-speed ADCs, other control modules, and data storage device. The Cherenkov light signals from an air shower are typically 10-100 ns long, and the waveforms are digitized with a sampling frequency of 1 GHz and recorded in situ without long-distance analog signal transfers. All the Cherenkov light detectors record their time-series data by receiving a triggering signal transmitted from the trigger module of the air shower array, which is fired by a coincidence of shower signals in four neighboring scintillation counters. The optical characteristics of the

  19. Hydrologic and mass-movement hazards near McCarthy Wrangell-St Elias National Park and Preserve, Alaska

    USGS Publications Warehouse

    Jones, S.H.; Glass, R.L.

    1993-01-01

    At the confluence of McCarthy Creek and the Kennicott River, about 1 mile from the terminus of Kennicott Glacier, Alaska, McCarthy Creek and Kennicott River basins are prone to several natural hazards including floods; formation and failure of natural dams; stream erosion and sediment deposi- tion; snow avalanches; aufeis; and the mass wasting of rock, soil, and debris. Low-lying areas along the Kennicott River flood annually, commonly during late July or early August, as a result of outbursts from glacier-dammed lakes, but these floods can occur during any month of the year. Flood plains along McCarthy Creek and its tributaries are frequently flooded and prone to rapid erosion and deposition during intense rainfall and periods of rapid snow- melt. Sediments from continual mass wasting accumu- late in stream channels and are mobilized during floods. Several lateral erosion, scour, and deposition resulting from floods in September 1980 and August 1985 destroyed bridges and several historic structures at McCarthy were jeopardized by the rapidly eroding northern streambank of McCarthy Creek. Flood discharges were determined indirectly using the slope-area method at two high-gradient reaches on the Kennicott River, four on McCarthy Creek, and one on Nikolai Creek. During the flood of September 13, 1980, peak discharge for McCarthy Creek at McCarthy was 4,500 cubic feet per second.

  20. Linear and cyclic methylsiloxanes in air by concurrent solvent recondensation-large volume injection-gas chromatography-mass spectrometry.

    PubMed

    Companioni-Damas, E Y; Santos, F J; Galceran, M T

    2014-01-01

    In the present work, a simple and fast method for the analysis of linear and cyclic methylsiloxanes in ambient air based on active sampling combined with gas chromatography - mass spectrometry (GC-MS) was developed. The retention efficiency of five sampling sorbents (activated coconut charcoal, Carbopack B, Cromosorb 102, Cromosorb 106 and Isolute ENV+) was evaluated and Isolute ENV+ was found to be the most effective. A volume of 2700 L of air can be sampled without significant losses of the most volatile methylsiloxanes. To improve the sensitivity of the GC-MS method, concurrent solvent recondensation - large volume injection (CSR-LVI), using volumes up to 30 µl of sample extract, is proposed and limits of quantification down to 0.03-0.45 ng m(-3), good linearity (r>0.999) and precision (RSD %<9%) were obtained. The developed method was applied to the analysis of ambient air. Concentrations of linear and cyclic methylsiloxanes in indoor air ranging from 3.9 to 319 ng m(-3) and between 48 and 292668 ng m(-3), were obtained, respectively, while levels from 6 to 22 ng m(-3) for linear and between 2.2 and 439 ng m(-3) for cyclic methylsiloxanes in outdoor air from Barcelona (Spain), were found.

  1. 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

  2. Structural uncertainty in air mass factor calculation for NO2 and HCHO satellite retrievals

    NASA Astrophysics Data System (ADS)

    Lorente, Alba; Folkert Boersma, K.; Yu, Huan; Dörner, Steffen; Hilboll, Andreas; Richter, Andreas; Liu, Mengyao; Lamsal, Lok N.; Barkley, Michael; De Smedt, Isabelle; Van Roozendael, Michel; Wang, Yang; Wagner, Thomas; Beirle, Steffen; Lin, Jin-Tai; Krotkov, Nickolay; Stammes, Piet; Wang, Ping; Eskes, Henk J.; Krol, Maarten

    2017-03-01

    Air mass factor (AMF) calculation is the largest source of uncertainty in NO2 and HCHO satellite retrievals in situations with enhanced trace gas concentrations in the lower troposphere. Structural uncertainty arises when different retrieval methodologies are applied within the scientific community to the same satellite observations. Here, we address the issue of AMF structural uncertainty via a detailed comparison of AMF calculation methods that are structurally different between seven retrieval groups for measurements from the Ozone Monitoring Instrument (OMI). We estimate the escalation of structural uncertainty in every sub-step of the AMF calculation process. This goes beyond the algorithm uncertainty estimates provided in state-of-the-art retrievals, which address the theoretical propagation of uncertainties for one particular retrieval algorithm only. We find that top-of-atmosphere reflectances simulated by four radiative transfer models (RTMs) (DAK, McArtim, SCIATRAN and VLIDORT) agree within 1.5 %. We find that different retrieval groups agree well in the calculations of altitude resolved AMFs from different RTMs (to within 3 %), and in the tropospheric AMFs (to within 6 %) as long as identical ancillary data (surface albedo, terrain height, cloud parameters and trace gas profile) and cloud and aerosol correction procedures are being used. Structural uncertainty increases sharply when retrieval groups use their preference for ancillary data, cloud and aerosol correction. On average, we estimate the AMF structural uncertainty to be 42 % over polluted regions and 31 % over unpolluted regions, mostly driven by substantial differences in the a priori trace gas profiles, surface albedo and cloud parameters. Sensitivity studies for one particular algorithm indicate that different cloud correction approaches result in substantial AMF differences in polluted conditions (5 to 40 % depending on cloud fraction and cloud pressure, and 11 % on average) even for low

  3. International system of units traceable results of Hg mass concentration at saturation in air from a newly developed measurement procedure.

    PubMed

    Quétel, Christophe R; Zampella, Mariavittoria; Brown, Richard J C; Ent, Hugo; Horvat, Milena; Paredes, Eduardo; Tunc, Murat

    2014-08-05

    Data most commonly used at present to calibrate measurements of mercury vapor concentrations in air come from a relationship known as the "Dumarey equation". It uses a fitting relationship to experimental results obtained nearly 30 years ago. The way these results relate to the international system of units (SI) is not known. This has caused difficulties for the specification and enforcement of limit values for mercury concentrations in air and in emissions to air as part of national or international legislation. Furthermore, there is a significant discrepancy (around 7% at room temperature) between the Dumarey data and data calculated from results of mercury vapor pressure measurements in the presence of only liquid mercury. As an attempt to solve some of these problems, a new measurement procedure is described for SI traceable results of gaseous Hg concentrations at saturation in milliliter samples of air. The aim was to propose a scheme as immune as possible to analytical biases. It was based on isotope dilution (ID) in the liquid phase with the (202)Hg enriched certified reference material ERM-AE640 and measurements of the mercury isotope ratios in ID blends, subsequent to a cold vapor generation step, by inductively coupled plasma mass spectrometry. The process developed involved a combination of interconnected valves and syringes operated by computer controlled pumps and ensured continuity under closed circuit conditions from the air sampling stage onward. Quantitative trapping of the gaseous mercury in the liquid phase was achieved with 11.5 μM KMnO4 in 2% HNO3. Mass concentrations at saturation found from five measurements under room temperature conditions were significantly higher (5.8% on average) than data calculated from the Dumarey equation, but in agreement (-1.2% lower on average) with data based on mercury vapor pressure measurement results. Relative expanded combined uncertainties were estimated following a model based approach. They ranged from 2

  4. Stability of reference masses: VII. Cleaning methods in air and vacuum applied to a platinum mass standard similar to the international and national kilogram prototypes

    NASA Astrophysics Data System (ADS)

    Cumpson, Peter J.; Sano, Naoko; Barlow, Anders J.; Portoles, Jose F.

    2013-10-01

    Mercury contamination and the build-up of carbonaceous contamination are two contributing factors to the instability observed in kilogram prototype masses. The kilogram prototypes that lie at the core of the dissemination of the SI base unit were manufactured in the late 19th century, and have polished surfaces. In papers IV and V of this series we developed a method for cleaning noble metal mass standards in air to remove carbonaceous contamination. At the core of this ‘UVOPS’ protocol is the application of UV light and ozone gas generated in situ in air. The precise nature of the carbonaceous contamination that builds up on such surfaces is difficult to mimic demonstrably or quickly on new test surfaces, yet data from such tests are needed to provide the final confidence to allow UVOPS to be applied to a real 19th century kilogram prototype. Therefore, in the present work we have applied the UVOPS method to clean a platinum avoirdupois pound mass standard, ‘RS2’, manufactured in the mid-19th century. This is thought to have been polished in a similar manner to the kilogram prototypes. To our knowledge this platinum surface has not previously been cleaned by any method. We used x-ray photoelectron spectroscopy to identify organic contamination, and weighing to quantify the mass lost at each application of the UVOPS procedure. The UVOPS procedure is shown to be very effective. It is likely that the redefinition of the kilogram will require mass comparisons in vacuum in the years to come. Therefore, in addition to UVOPS a cleaning method for use in vacuum will also be needed. We introduce and evaluate gas cluster ion-beam (GCIB) treatment as a potential method for cleaning reference masses in vacuum. Again, application of this GCIB cleaning to a real artefact, RS2, allows us to make a realistic evaluation of its performance. While it has some attractive features, we cannot recommend it for cleaning mass standards in its present form.

  5. 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.

  6. Reconstructing ~2,200 years of mass movement and tsunami events in a deep fjord-type lake, western Norway

    NASA Astrophysics Data System (ADS)

    Waldmann, Nicolas; Vasskog, Kristian; Simpson, Guy; Hansen, Louise; Ariztegui, Daniel; Chapron, Emmanuel; Nesje, Atle

    2016-04-01

    Rock avalanches are one of the most devastating geohazards in Norway. A recent example can be given by the September 1936 rock fall that released ca. 1 million m3 of gneissic bedrock from the Ramnefjell Mountain, 800 m above Lake Lovatnet in inner Nordfjord, western Norway. The rock fall plunged into the lake causing a tsunami with a maximum run-up of 74 m and causing 74 casualties. This rock failure opened a deep-seated fracture that may serve as a sliding surface threatening for the generation of potential new series of failures. Lake Lovatnet was surveyed combining simultaneously 1 in3 airgun multi-channel and 3.5 kHz (pinger) single-channel systems. The seismic survey was complemented by piston cores. The general seismic stratigraphy of the lake was reconstructed using the 1 in3 airgun multi-channel survey. The seismic data shows an overall succession of glaciomarine sediments deposited during glacier retreat at the termination of the last ice age and a transition to marine and lacustrine sedimentation, as glacio-isostatic rebound turned the fjord into a land-locked lake. Furthermore, a record of ~2200 years of mass wasting events were identified and dated in the sedimentary record and the events were further mapped in the geophysical data. A specially tailored physically-based numerical simulation was carried out on the 1936 rock fall and related tsunami event in Lake Lovatnet. This model allowed us to reconstruct the effects of such an event on a small lacustrine basin. The outcome of the model has been further validated against historical, marine and terrestrial information. Results from this study further permit to extend the record of mass wasting events beyond historical times, providing a data set that can be applied to comparable basins at various temporal and geographical scales.

  7. 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.

  8. Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

    SciTech Connect

    Gupta, A.; Biswas, P. ); Monson, P.R. ); Novick, V.J. )

    1993-07-01

    The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K[sub 2] was computed for different test conditions and used as a measure of the mass loading capacity. K[sub 2] was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K[sub 2] for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs.

  9. Air Superiority at Red Flag: Mass, Technology, and Winning the Next War

    DTIC Science & Technology

    2009-10-01

    improved their estimate. In The Art of Wargaming, Peter Perla suggests that adding exercise analysis could help. He recommends a “continuous cycle...Survey, 44. 45. Ibid., 27–28. 46. “Desert Shield Tactical Air Force Combat Losses, Damage, and Muni- tions Consumption.” 47. Ibid. 48. Perla , Art of...Williamson. Strategy for Defeat: The Luftwaffe, 1933– 1945, 1983. Reprint. Maxwell AFB, AL: Air University Press, 2007. Perla , Peter P. The Art of Wargaming

  10. Consequences of postural changes and removal of vestibular inputs on the movement of air in and out of the lungs of conscious felines.

    PubMed

    Arshian, M; Holtje, R J; Cotter, L A; Rice, C D; Cass, S P; Yates, B J

    2007-07-01

    A variety of experimental approaches in human subjects and animal models established that the vestibular system contributes to regulation of respiration. In cats, the surgical elimination of labyrinthine signals produced changes in the spontaneous activity and posturally related responses of a number of respiratory muscles. However, these effects were complex and sometimes varied between muscle compartments, such that the physiological role of vestibulo-respiratory responses is unclear. The present study determined the functional significance of vestibulo-respiratory influences by examining the consequences of a bilateral labyrinthectomy on breathing rate and the pressure, volume, and flow rate of air exchanged during inspiration and expiration as body orientation with respect to gravity was altered. Data were collected from conscious adult cats acclimated to breathing through a facemask connected to a pneuomotach during 60 degrees head-up pitch and ear-down roll body rotations. Removal of vestibular inputs resulted in a 15% reduction in breathing rate, a 13% decrease in minute ventilation, a 16% decrease in maximal inspiratory airflow rate, and a 14% decrease in the maximal expiratory airflow rate measured when the animals were in the prone position. However, the lesions did not appreciably affect phasic changes in airflow parameters related to alterations in posture. These results suggest that the role of the vestibular system in the control of breathing is to modify baseline respiratory parameters in proportion to the general intensity of ongoing movements, and not to rapidly alter ventilation in accordance with body position.

  11. EPA Air Method, Toxic Organics - 15 (TO-15): Determination of Volatile Organic Compounds (VOCs) in Air Collected in Specially-Prepared Canisters and Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS)

    EPA Pesticide Factsheets

    Method T)-15 describes procedures for for preparation and analysis of air samples containing volatile organic compounds collected in specially-prepared canisters, using gas chromatography-mass spectrometry.

  12. 129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

    PubMed Central

    Liu, Dan; Hou, Xiaolin; Du, Jinzhou; Zhang, Luyuan; Zhou, Weijian

    2016-01-01

    Anthropogenic 129I as a long-lived radioisotope of iodine has been considered as an ideal oceanographic tracer due to its high residence time and conservative property in the ocean. Surface water samples collected from the East China Sea (ECS) in August 2013 were analyzed for 129I, 127I and their inorganic chemical species in the first time. The measured 129I/127I ratio is 1–3 orders of magnitude higher than the pre-nuclear level, indicating its dominantly anthropogenic sources. Relatively high 129I levels were observed in the Yangtze River and its estuary, as well as in the southern Yellow Sea, and 129I level in seawater declines towards the ECS shelf. In the open sea, 129I and 127I in surface water exists mainly as iodate, while in Yangtze River estuary and some locations, iodide is dominated. The results indicate that the Fukushima nuclear accident has no detectable effects in the ECS until August 2013. The obtained results are used for investigation of interaction of various water masses and water circulation in the ECS, as well as the marine environment in this region. Meanwhile this work provides essential data for evaluation of the possible influence of the increasing NPPs along the coast of the ECS in the future. PMID:27849026

  13. 129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

    NASA Astrophysics Data System (ADS)

    Liu, Dan; Hou, Xiaolin; Du, Jinzhou; Zhang, Luyuan; Zhou, Weijian

    2016-11-01

    Anthropogenic 129I as a long-lived radioisotope of iodine has been considered as an ideal oceanographic tracer due to its high residence time and conservative property in the ocean. Surface water samples collected from the East China Sea (ECS) in August 2013 were analyzed for 129I, 127I and their inorganic chemical species in the first time. The measured 129I/127I ratio is 1–3 orders of magnitude higher than the pre-nuclear level, indicating its dominantly anthropogenic sources. Relatively high 129I levels were observed in the Yangtze River and its estuary, as well as in the southern Yellow Sea, and 129I level in seawater declines towards the ECS shelf. In the open sea, 129I and 127I in surface water exists mainly as iodate, while in Yangtze River estuary and some locations, iodide is dominated. The results indicate that the Fukushima nuclear accident has no detectable effects in the ECS until August 2013. The obtained results are used for investigation of interaction of various water masses and water circulation in the ECS, as well as the marine environment in this region. Meanwhile this work provides essential data for evaluation of the possible influence of the increasing NPPs along the coast of the ECS in the future.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2012-04-01

    Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM1) was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions, could be identified in the particle phase

  19. 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

  20. 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.

  1. Numerical study of coupled transfer of heat and mass between air and water inside a geothermal water cooling tower

    NASA Astrophysics Data System (ADS)

    Bassem, Mohamed Mehdi; Bourouni, Karim; Thameur Chaibi, Mohamed

    2006-11-01

    In the south of Tunisia, geothermal water is used to irrigate cultures. Since its temperature is very high (70 C), geothermal water is cooled by cooling towers. These towers are sized empirically and present many operating problems such as excessive energy consumption, big loss of vapour and low cooling efficiency. The aim of our work is modelling the coupled heat and mass transfer between air and water inside the cooling tower. The most important results obtained are that the evaporative potential is dominating the convective one in the cooling process. That's why the cooling is more efficient in summer than in hibernal period when humidity of ambient air reaches high values. In other hand, the negative convective phenomenon is illustrated. In fact, at the bottom of the tower, water temperature reaches the air one; the two fluids begin to cooling simultaneously. Air is cooled by convection and water by evaporation. We demonstrate also that there is no point in putting fans in working during cold weather. We studied also the effect of the variation of heat transfer coefficient on the efficiency of cooling.

  2. Petroleum mass removal from low permeability sediment using air sparging/soil vapor extraction: impact of continuous or pulsed operation

    NASA Astrophysics Data System (ADS)

    Kirtland, Brian C.; Aelion, C. Marjorie

    2000-02-01

    Air sparging and soil vapor extraction (AS/SVE) are innovative remediation techniques that utilize volatilization and microbial degradation to remediate petroleum spills from soils and groundwater. This in situ study investigated the use of AS/SVE to remediate a gasoline spill from a leaking underground storage tank (UST) in the low permeability, clayey soil of the Appalachian Piedmont. The objectives of this study were to evaluate AS/SVE in low permeability soils by quantifying petroleum mass removal rates, monitoring vadose zone contaminant levels, and comparing the mass extraction rates of continuous AS/SVE to 8 and 24 h pulsed operation. The objectives were met by collecting AS/SVE exhaust gas samples and vadose zone air from multi-depth soil vapor probes. Samples were analyzed for O 2, CO 2, BTEX (benzene, toluene, ethylbenzene, xylene), and total combustible hydrocarbon (TCH) concentrations using portable hand meters and gas chromatography. Continuous AS/SVE was effective in removing 608 kg of petroleum hydrocarbons from low permeability soil in 44 days (14.3 kg day -1). Mass removal rates ranged from 2.6 times higher to 5.1 times lower than other AS/SVE studies performed in sandy sediments. BTEX levels in the vadose zone were reduced from about 5 ppm to 1 ppm. Ten pulsed AS/SVE tests removed 78 kg in 23 days and the mean mass removal rate (17.6 kg day -1) was significantly higher than the last 15 days of continuous extraction. Pulsed operation may be preferable to continuous operation because of increased mass removal and decreased energy consumption.

  3. Ambient air analyses using nonspecific flame ionization and electron capture detection compared to specific detection by mass spectroscopy

    SciTech Connect

    Pleil, J.D.; Oliver, K.D.; McClenny, W.A.

    1988-08-01

    Ambient air samples from various studies were analyzed for a specific set of trace-level volatile organic compounds by using a gas chromatograph (GC) equipped with a flame ionization detector (FID) in parallel with an electron capture detector (ECD). The samples were then reanalyzed on a second GC system equipped with a mass selective detector (MSD). GC-FID/ECD data were compared to the nominally correct GC-MSD data to determine the accuracy of the nonspecific detectors, which often do not differentiate the targeted compound from interfering compounds. Qualitative accuracy (capability for correctly identifying compounds on the basis of retention time only) and quantitative accuracy (capability for correctly measuring the concentration of an identified compound on the basis of peak area) were evaluated. Data are presented on a per-compound basis to provide the combined typical results from air samples collected in three geographic regions: Kanawha Valley, WV; Los Angeles, CA, area; and Houston, TX.

  4. 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.

    2017-01-01

    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.

  5. Ground-water flow in the surficial aquifer system and potential movement of contaminants from selected waste-disposal sites at Cecil Field Naval Air Station, Jacksonville, Florida

    USGS Publications Warehouse

    Halford, K.J.

    1998-01-01

    As part of the Installation Restoration Program, Cecil Field Naval Air Station, Jacksonville, Florida, is considering remedialaction alternatives to control the possible movement of contaminants from sites that may discharge to the surface. This requires a quantifiable understanding of ground-water flow through the surficial aquifer system and how the system will respond to any future stresses. The geologic units of interest in the study area consist of sediments of Holocene to Miocene age that extend from land surface to the base of the Hawthorn Group. The hydrogeology within the study area was determined from gamma-ray and geologists? logs. Ground-water flow through the surficial aquifer system was simulated with a seven-layer, finite-difference model that extended vertically from the water table to the top of the Upper Floridan aquifer. Results from the calibrated model were based on a long-term recharge rate of 6 inches per year, which fell in the range of 4 to 10 inches per year, estimated using stream hydrograph separation methods. More than 80 percent of ground-water flow circulates within the surficial-sand aquifer, which indicates that most contaminant movement also can be expected to move through the surficial-sand aquifer alone. The surficial-sand aquifer is the uppermost unit of the surficial aquifer system. Particle-tracking results showed that the distances of most flow paths were 1,500 feet or less from a given site to its discharge point. For an assumed effective porosity of 20 percent, typical traveltimes are 40 years or less. At all of the sites investigated, particles released 10 feet below the water table had shorter traveltimes than those released 40 feet below the water table. Traveltimes from contaminated sites to their point of discharge ranged from 2 to 300 years. The contributing areas of the domestic supply wells are not very extensive. The shortest traveltimes for particles to reach the domestic supply wells from their respective

  6. Identifying tropospheric baseline air masses at Mauna Loa Observatory between 2004 and 2010 using Radon-222 and back trajectories

    NASA Astrophysics Data System (ADS)

    Chambers, Scott D.; Zahorowski, Wlodek; Williams, Alastair G.; Crawford, Jagoda; Griffiths, Alan D.

    2013-01-01

    We use 7 years of hourly radon observations at Mauna Loa Observatory (MLO), together with 10-day back trajectories, to identify baseline air masses at the station. The amplitude of the annual MLO radon cycle, based on monthly means, was 98 mBq m-3 (39 -137 mBq m-3), with maximum values in February (90th percentile 330 mBq m-3) and minimum values in August (10th percentile 8.1 mBq m-3). The composite diurnal radon cycle (amplitude 49 mBq m-3) is discussed with reference to the influences of local flow features affecting the site, and a 3-hour diurnal sampling window (0730-1030 HST) is proposed for observing the least terrestrially influenced tropospheric air masses. A set of 763 baseline events is selected, using the proposed sampling window together with trajectory information, and presented along with measured radon concentrations as a supplement. This data set represents a resource for the selection of baseline events at MLO for use with a range of trace species. A reduced set of 196 "deep baseline" events occurring in the July-September window is also presented and discussed. The distribution (10th/50th/90th percentile) of radon in deep-baseline events (8.7/29.2/66.1 mBq m-3) was considerably lower than that for the overall set of 763 baseline events (12.3/40.8/104.1 mBq m-3). Results from a simple budget calculation, using sonde-derived mixing depths and literature-based estimates of oceanic radon flux and radon concentrations in the marine boundary layer, indicate that the main source of residual radon in the lower troposphere under baseline conditions at MLO is downward mixing from aged terrestrial air masses in the upper troposphere.

  7. 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.

  8. 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.

  9. Bowel Movement

    MedlinePlus

    A bowel movement is the last stop in the movement of food through your digestive tract. Your stool passes out ... rectum and anus. Another name for stool is feces. It is made of what is left after ...

  10. Movement - uncontrollable

    MedlinePlus

    ... peripheral nervous system References Jankovic J, Lang AE. Movement disorders: diagnosis and assessment. In: Daroff RB, Fenichel GM, ... Elsevier Saunders; 2012:chap 21. Lang AE. Other movement disorders. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  11. Near-road air pollution impacts of goods movement in communities adjacent to the Ports of Los Angeles and Long Beach

    NASA Astrophysics Data System (ADS)

    Kozawa, Kathleen H.; Fruin, Scott A.; Winer, Arthur M.

    A mobile platform was outfitted with real-time instruments to spatially characterize pollution concentrations in communities adjacent to the Ports of Los Angeles and Long Beach, communities heavily impacted by emissions related to dieselized goods movement, with the highest localized air pollution impacts due to heavy-duty diesel trucks (HDDT). Measurements were conducted in the winter and summer of 2007 on fixed routes driven both morning and afternoon. Diesel-related pollutant concentrations such as black carbon, nitric oxide, ultrafine particles, and particle-bound polycyclic aromatic hydrocarbons were frequently elevated two to five times within 150 m downwind of freeways (compared to more than 150 m) and up to two times within 150 m downwind of arterial roads with significant amounts of diesel traffic. While wind direction was the dominant factor associated with downwind impacts, steady and consistent wind direction was not required to produce; high impacts were observed when a given area was downwind of a major roadway for any significant fraction of time. This suggests elevated pollution impacts downwind of freeways and of busy arterials are continuously occurring on one side of the road or the other, depending on wind direction. The diesel truck traffic in the area studied was high, with more than 2000 trucks per peak hour on the freeway and two- to six-hundred trucks per hour on the arterial roads studied. These results suggest that similarly-frequent impacts occur throughout urban areas in rough proportion to diesel truck traffic fractions. Thus, persons living or working near and downwind of busy roadways can have several-fold higher exposures to diesel vehicle-related pollution than would be predicted by ambient measurements in non-impacted locations.

  12. Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer.

    PubMed

    Smith, Jonell N; Noll, Robert J; Cooks, R Graham

    2011-05-30

    Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

    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 22cm diameter and 30cm length, purifies an airflow rate of 5000lpm 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.

  15. Identification of European Air Masses Using an Interactive Computer Technique for Separating Mixed Normal Distributions.

    DTIC Science & Technology

    1982-01-01

    classifying a maritime surface, he refers to the Pacific, Atlantic, or Gulf of Mexico using the general term "maritime" only when the exact origin is...portions of North Atlantic NPA PA air modified over warm North Atlantic TC Southern U.S. and Northern Mexico TG Gulf of Mexico and Caribbean NTG TG...Bergeron, T., 1928: " Uber Die Dreidimensional Verknupfende Wetteranalyse, Teil I." Geofys. Pub!., Vol. 5, No. 6. Berggren, R., 1953: "On Temperature

  16. Properties of individual aerosol particles and their relation to air mass origins in a south China coastal city

    NASA Astrophysics Data System (ADS)

    Shi, Zongbo; He, Kebin; Xue, Zhigang; Yang, Fumo; Chen, Yanju; Ma, Yongliang; Luo, Jiaojiao

    2009-05-01

    Atmospheric particles in urban and rural areas in Shenzhen city were collected in summer and winter 2004. The particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. The fine particles (<1 μm) were categorized into chain-like, elongated, rounded, and others on the basis of their morphology. Chain-like particles were likely soot aggregates. In summer and winter, chain-like particles accounted for 43% and 42% of total particles in the urban area, and 22% and 43% in the rural area, respectively. The elongated particles were mixtures of aged sea salts and ammonium sulfate, suggesting an aqueous phase reaction mechanism, i.e., in-cloud sulfate formation. Such particles occupied 12% of total particles in the urban area in the summer and were rarely observed in the wintertime samples. The rounded particles were mainly composed of sulfate and/or carbon. Their number concentration in the urban area was more than three times higher in the winter. In addition, we found that air masses from northern inland contained much higher concentrations of particles than those from the ocean. This was particularly evident in the rural area, where concentrations of chain-like and rounded particles were eight times higher in the continental air masses. These results suggest the strong influence of regional pollution on the particle number concentrations in the coastal city.

  17. 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.

  18. An improved, automated whole air sampler and gas chromatography mass spectrometry analysis system for volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Lerner, Brian M.; Gilman, Jessica B.; Aikin, Kenneth C.; Atlas, Elliot L.; Goldan, Paul D.; Graus, Martin; Hendershot, Roger; Isaacman-VanWertz, Gabriel A.; Koss, Abigail; Kuster, William C.; Lueb, Richard A.; McLaughlin, Richard J.; Peischl, Jeff; Sueper, Donna; Ryerson, Thomas B.; Tokarek, Travis W.; Warneke, Carsten; Yuan, Bin; de Gouw, Joost A.

    2017-01-01

    Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography-mass spectrometry instrument. During flight, air samples were pressurized with a stainless steel bellows compressor into electropolished stainless steel canisters. The air samples were analyzed using a novel gas chromatograph system designed specifically for field use which eliminates the need for liquid nitrogen. Instead, a Stirling cooler is used for cryogenic sample pre-concentration at temperatures as low as -165 °C. The analysis system was fully automated on a 20 min cycle to allow for unattended processing of an entire flight of 72 sample canisters within 30 h, thereby reducing typical sample residence times in the canisters to less than 3 days. The new analytical system is capable of quantifying a wide suite of C2 to C10 organic compounds at part-per-trillion sensitivity. This paper describes the sampling and analysis systems, along with the data analysis procedures which include a new peak-fitting software package for rapid chromatographic data reduction. Instrument sensitivities, uncertainties and system artifacts are presented for 35 trace gas species in canister samples. Comparisons of reported mixing ratios from each field campaign with measurements from other instruments are also presented.

  19. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J. C.; Sodeau, J. R.; Healy, R. M.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; O'Dowd, C. D.

    2009-12-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the NE Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Black carbon concentrations in polluted air were between 300-400 ng m-3, and in clean marine air were less than 50 ng m-3. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water

  20. Identification of oxidation products of solanesol produced during air sampling for tobacco smoke by electrospray mass spectrometry and HPLC.

    PubMed

    Tucker, Samuel P; Pretty, Jack R

    2005-10-01

    Solanesol, a 45-carbon, trisesquiterpenoid alcohol found in tobacco leaves and tobacco smoke, has been used as a quantitative marker for tobacco smoke for years. However, solanesol appears to be unreliable as a quantitative marker for tobacco smoke during environmental air sampling because it can be degraded substantially when present as a component of tobacco smoke and by as much as 100% when present as pure solanesol on fortified filters during air sampling. Since there is strong evidence that ozone is the agent responsible for the degradation, solanesol appears to be unreliable as a quantitative marker during indoor air sampling when indoor levels of ozone are greater than about 15 ppb. The degree of loss of pure solanesol is directly proportional to the concentration of ozone and the length of the sampling period and depends on the type of 37 mm membrane filter used for air sampling (PTFE or quartz fiber). While the degree of loss of solanesol is inversely proportional to the relative humidity of the air at a sampling rate of 1.7 L min(-1), the degree of loss is virtually independent of relative humidity at a lower sampling rate; i.e., 0.25 L min(-1). A curve of loss of solanesol on a filter versus concentration of ozone from an ozone generator is virtually identical to a curve segment based on atmospheric ozone under the same conditions of air sampling. Oxidation of solanesol by ozone to approximately 25 to 60% completion produces at least three series of products for a total of at least 26 compounds: (1) isoprenoid acetones, (2)omega-hydroxyisoprenoid acetaldehydes, and (3) isoprenoid oxoaldehydes. All products in each series were tentatively identified as their derivatives with 2-(p-aminophenyl)ethanol (APE) by electrospray mass spectrometry (ES-MS). Ten ozonation products were detected as their 2,4-dinitrophenylhydrazine derivatives by HPLC at 360 nm: 4-oxopentanal and nine isoprenoid acetones (acetone, 6-methyl-5-hepten-2-one, geranylacetone

  1. Upper air relaxation in regional climate model improves resolved interannual variability of the surface mass balance of Antarctica

    NASA Astrophysics Data System (ADS)

    van de Berg, Willem Jan; Medley, Brooke; van Meijgaard, Erik

    2015-04-01

    The surface mass balance (SMB) determines the variability of the mass balance of the Antarctic Ice sheet on sub-decadal timescales. Since continent-wide SMB cannot be measured, it must be modeled and regional climate models (RCMs) generally outperform global reanalyses in the representation of total mass flux and the spatial distribution of SMB. However, if RCMs are only forced with reanalysis on their lateral boundaries, the representation of the interannual variability of SMB deteriorates significantly. In this study we show how to improve the resolved interannual variability in RCM modeled SMB. For this purpose we use annual SMB observations in the Thwaites drainage basin in Antarctica derived from airborne radar reflections and the RCM RACMO2. RACMO2, driven by ERA-Interim, better represents the mean spatial SMB pattern in this basin than ERA-Interim. However, without relaxation in the interior, RACMO2 poorly resolves the observed interannual SMB variability. If we gently relax the temperature and wind field in the upper atmosphere in RACMO2 to ERA-Interim, RACMO2 gets the best of both. Upper air relaxation little changes the mean SMB and spatial pattern compared to the original RACMO2 output, but allows RACMO2 to resolve the observed interannual SMB as good as ERA-Interim.

  2. Decomposing the profile of PM in two low polluted German cities--mapping of air mass residence time, focusing on potential long range transport impacts.

    PubMed

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2014-07-01

    This paper aims to decompose the profile of particulates in Karlsruhe and Potsdam (Germany), focusing on the localization of PM potential transboundary sources. An air mass cluster analysis was implemented, followed by a study of air mass residence time on a grid of a 0.5° × 0.5° resolution. Particulate/gaseous daily air pollution and meteorological data were used to indicate PM local sources. Four Principal Component Analysis (PCA) components were produced: traffic, photochemical, industrial/domestic and particulate. PM2.5/PM10 ratio seasonal trends, indicated production of PMCOARSE (PM10-PM2.5) from secondary sources in Potsdam during warm period (WP). The residing areas of incoming slow moving air masses are potential transboundary PM sources. For Karlsruhe those areas were mainly around the city. An air mass residence time secondary peak was observed over Stuttgart. For Potsdam, areas with increased dwelling time of the arriving air parcels were detected particularly above E/SE Germany.

  3. 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

  4. Differential optical absorption spectroscopy (DOAS) and air mass factor concept for a multiply scattering vertically inhomogeneous medium: theoretical consideration

    NASA Astrophysics Data System (ADS)

    Rozanov, V. V.; Rozanov, A. V.

    2010-06-01

    The Differential Optical Absorption Spectroscopy (DOAS) technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering. Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS), the modified (MDOAS), and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption. The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as well as of the relationship between

  5. Differential optical absorption spectroscopy (DOAS) and air mass factor concept for a multiply scattering vertically inhomogeneous medium: theoretical consideration

    NASA Astrophysics Data System (ADS)

    Rozanov, V. V.; Rozanov, A. V.

    2010-02-01

    The Differential Optical Absorption Spectroscopy (DOAS) technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering. Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS), the modified (MDOAS), and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption. The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as well as of the relationship between

  6. [Stereotypic movements].

    PubMed

    Fernández-Alvarez, E

    2003-02-01

    Stereotypic movements are repetitive patterns of movement with certain peculiar features that make them especially interesting. Their physiopathology and their relationship with the neurobehavioural disorders they are frequently associated with are unknown. In this paper our aim is to offer a simple analysis of their dominant characteristics, their differentiation from other processes and a hypothesis of the properties of stereotypic movements, which could all set the foundations for research work into their physiopathology.

  7. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J.; Healy, R.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; Ehn, M.; Mikkilä, J.; Kulmala, M.; O'Dowd, C. D.

    2010-09-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June, 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the N. E. Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water soluble organic carbon, which, in turn, was dominated by methanesulphonic acid (MSA). Sulphate concentrations were

  8. 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.

  9. Characterisation of a smartphone image sensor response to direct solar 305nm irradiation at high air masses.

    PubMed

    Igoe, D P; Amar, A; Parisi, A V; Turner, J

    2017-06-01

    This research reports the first time the sensitivity, properties and response of a smartphone image sensor that has been used to characterise the photobiologically important direct UVB solar irradiances at 305nm in clear sky conditions at high air masses. Solar images taken from Autumn to Spring were analysed using a custom Python script, written to develop and apply an adaptive threshold to mitigate the effects of both noise and hot-pixel aberrations in the images. The images were taken in an unobstructed area, observing from a solar zenith angle as high as 84° (air mass=9.6) to local solar maximum (up to a solar zenith angle of 23°) to fully develop the calibration model in temperatures that varied from 2°C to 24°C. The mean ozone thickness throughout all observations was 281±18 DU (to 2 standard deviations). A Langley Plot was used to confirm that there were constant atmospheric conditions throughout the observations. The quadratic calibration model developed has a strong correlation between the red colour channel from the smartphone with the Microtops measurements of the direct sun 305nm UV, with a coefficient of determination of 0.998 and very low standard errors. Validation of the model verified the robustness of the method and the model, with an average discrepancy of only 5% between smartphone derived and Microtops observed direct solar irradiances at 305nm. The results demonstrate the effectiveness of using the smartphone image sensor as a means to measure photobiologically important solar UVB radiation. The use of ubiquitous portable technologies, such as smartphones and laptop computers to perform data collection and analysis of solar UVB observations is an example of how scientific investigations can be performed by citizen science based individuals and groups, communities and schools.

  10. 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.

  11. The collision cross sections of iodide salt cluster ions in air via differential mobility analysis-mass spectrometry.

    PubMed

    Ouyang, Hui; Larriba-Andaluz, Carlos; Oberreit, Derek R; Hogan, Christopher J

    2013-12-01

    To date, most collision cross section (CCS) predictions have invoked gas molecule impingement-reemission rules in which specular and elastic scattering of spherical gas molecules from rigid polyatomic surfaces are assumed. Although such predictions have been shown to agree well with CCSs measured in helium bath gas, a number of studies reveal that these predictions do not agree with CCSs for ions in diatomic gases, namely, air and molecular nitrogen. To further examine the validity of specular-elastic versus diffuse-inelastic scattering models, we measured the CCSs of positively charged metal iodide cluster ions of the form [MI]n[M(+)]z, where M = Na, K, Rb, or Cs, n = 1 - 25, and z = 1 - 2. Measurements were made in air via differential mobility analysis mass spectrometry (DMA-MS). The CCSs measured are compared with specular-elastic as well as diffuse-inelastic scattering model predictions with candidate ion structures determined from density functional theory. It is found that predictions from diffuse-inelastic collision models agree well (within 5%) with measurements from sodium iodide cluster ions, while specular-elastic collision model predictions are in better agreement with cesium iodide cluster ion measurements. The agreement with diffuse-inelastic and specular-elastic predictions decreases and increases, respectively, with increasing cation mass. However, even when diffuse-inelastic cluster ion predictions disagree with measurements, the disagreement is of a near-constant factor for all ions, indicating that a simple linear rescaling collapses predictions to measurements. Conversely, rescaling cannot be used to collapse specular-elastic predictions to measurements; hence, although the precise impingement reemission rules remain ambiguous, they are not specular-elastic.

  12. 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.

  13. The Collision Cross Sections of Iodide Salt Cluster Ions in Air via Differential Mobility Analysis-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ouyang, Hui; Larriba-Andaluz, Carlos; Oberreit, Derek R.; Hogan, Christopher J.

    2013-12-01

    To date, most collision cross section (CCS) predictions have invoked gas molecule impingement-reemission rules in which specular and elastic scattering of spherical gas molecules from rigid polyatomic surfaces are assumed. Although such predictions have been shown to agree well with CCSs measured in helium bath gas, a number of studies reveal that these predictions do not agree with CCSs for ions in diatomic gases, namely, air and molecular nitrogen. To further examine the validity of specular-elastic versus diffuse-inelastic scattering models, we measured the CCSs of positively charged metal iodide cluster ions of the form [MI]n[M+]z, where M = Na, K, Rb, or Cs, n = 1 - 25, and z = 1 - 2. Measurements were made in air via differential mobility analysis mass spectrometry (DMA-MS). The CCSs measured are compared with specular-elastic as well as diffuse-inelastic scattering model predictions with candidate ion structures determined from density functional theory. It is found that predictions from diffuse-inelastic collision models agree well (within 5 %) with measurements from sodium iodide cluster ions, while specular-elastic collision model predictions are in better agreement with cesium iodide cluster ion measurements. The agreement with diffuse-inelastic and specular-elastic predictions decreases and increases, respectively, with increasing cation mass. However, even when diffuse-inelastic cluster ion predictions disagree with measurements, the disagreement is of a near-constant factor for all ions, indicating that a simple linear rescaling collapses predictions to measurements. Conversely, rescaling cannot be used to collapse specular-elastic predictions to measurements; hence, although the precise impingement reemission rules remain ambiguous, they are not specular-elastic.

  14. 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

  15. 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

  16. Development of a thermal desorption-gas chromatography-mass spectrometry method for determining personal care products in air.

    PubMed

    Ramírez, Noelia; Marcé, Rosa Maria; Borrull, Francesc

    2010-06-25

    This study describes the development of a new analytical method for determining 14 personal care products (PCPs) - nine synthetic musks, four parabens and one insect repellent - in air samples. The method is based on active sampling on sorbent tubes and thermal desorption-gas chromatography-mass spectrometry analysis, and is rapid, sensitive and drastically reduces the risk of sample contamination. Three kinds of tubes and traps were tested, those filled with Tenax TA being the most suitable for this study. Method validation showed good repeatability and reproducibility, low detection limits (between 0.03 ng m(-3) for DPMI and 12.5 ng m(-3) for propyl paraben) and good linearity for all compounds. Stability during storage indicated that samples must be kept refrigerated at 4 degrees C and analysed within 1 week of collection. The applicability of the technique to real samples was tested in different indoor and outdoor atmospheres. The total PCP values for indoor air ranged from 135 ng m(-3) in a pharmacy to 2838 ng m(-3) in a hairdresser's, whereas the values for outdoor air ranged from 14 ng m(-3) for a suburban environment to 26 ng m(-3) for an urban environment. In general, the most abundant synthetic musks were galaxolide (5.9-1256 ng m(-3)), musk xylene (1.6-766 ng m(-3)) and tonalide (1.1-138 ng m(-3)). Methyl and ethyl paraben (2.4-313 ng m(-3) and 1.8-117 ng m(-3), respectively) were the most abundant parabens. Although thermal desorption methods have been widely used for determining volatile organic compounds, they are rarely used with semi-volatile compounds. This study thus demonstrates that the thermal desorption method performs well with semi-volatile compounds and, for the first time, that it can be used for determining PCPs.

  17. 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.

  18. 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

    2013-03-05

    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.

  19. Simulation of solid oxide iron-air battery: Effects of heat and mass transfer on charge/discharge characteristics

    NASA Astrophysics Data System (ADS)

    Ohmori, Hiroko; Iwai, Hiroshi

    2015-07-01

    A time-dependent 2-D numerical simulation was performed on a solid oxide iron-air battery (SOIAB) to reveal the fundamental characteristics of this new system. The SOIAB is a rechargeable battery consisting of a solid oxide electrochemical cell (SOEC) and iron as a redox metal. A simple battery configuration was employed assuming a system with a small capacity. A simulation model for a unit element was developed considering heat and mass transfer in the system, taking both electrochemical and redox reactions into account. The numerical results showed the spatial and temporal changes in the temperature field in the charge and discharge operations, which were due to the combined effects of heat generation/absorption by the electrochemical and redox reactions and heat exchange with the air supplied through convective heat transfer. As the reaction rates are functions of the local temperature, the predicted results show the importance of considering the heat transfer phenomena in this system. It was also found that the active reaction region in the redox metal evolves with time. The nonuniform distribution of iron utilization is affected by the effective gas diffusion coefficients in the porous redox metal, and consequently the change in the current density distribution in the SOEC.

  20. 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).

  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. Measurement error models in chemical mass balance analysis of air quality data

    NASA Astrophysics Data System (ADS)

    Christensen, William F.; Gunst, Richard F.

    The chemical mass balance (CMB) equations have been used to apportion observed pollutant concentrations to their various pollution sources. Typical analyses incorporate estimated pollution source profiles, estimated source profile error variances, and error variances associated with the ambient measurement process. Often the CMB model is fit to the data using an iteratively re-weighted least-squares algorithm to obtain the effective variance solution. We consider the chemical mass balance model within the framework of the statistical measurement error model (e.g., Fuller, W.A., Measurement Error Models, Wiley, NewYork, 1987), and we illustrate that the models assumed by each of the approaches to the CMB equations are in fact special cases of a general measurement error model. We compare alternative source contribution estimators with the commonly used effective variance estimator when standard assumptions are valid and when such assumptions are violated. Four approaches for source contribution estimation and inference are compared using computer simulation: weighted least squares (with standard errors adjusted for source profile error), the effective variance approach of Watson et al. (Atmos, Environ., 18, 1984, 1347), the Britt and Luecke (Technometrics, 15, 1973, 233) approach, and a method of moments approach given in Fuller (1987, p. 193). For the scenarios we consider, the simplistic weighted least-squares approach performs as well as the more widely used effective variance solution in most cases, and is slightly superior to the effective variance solution when source profile variability is large. The four estimation approaches are illustrated using real PM 2.5 data from Fresno and the conclusions drawn from the computer simulation are validated.

  3. Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; Cooper, O. R.; Warneke, C.; Hudson, P. K.; Fehsenfeld, F. C.; Holloway, J. S.; Hübler, G.; Nicks, D. K., Jr.; Nowak, J. B.; Parrish, D. D.; Ryerson, T. B.; Atlas, E. L.; Donnelly, S. G.; Schauffler, S. M.; Stroud, V.; Johnson, K.; Carmichael, G. R.; Streets, D. G.

    2004-12-01

    As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators.

  4. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with continental, urban and marine air masses at the SW Atlantic coast of Iberia

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2011-12-01

    Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions could be identified in the particle phase. In all

  5. Chloroplast movement.

    PubMed

    Wada, Masamitsu; Kagawa, Takatoshi; Sato, Yoshikatsu

    2003-01-01

    The study of chloroplast movement made a quantum leap at the beginning of the twenty-first century. Research based on reverse-genetic approaches using targeted mutants has brought new concepts to this field. One of the most exciting findings has been the discovery of photoreceptors for both accumulation and avoidance responses in Arabidopsis and in the fern Adiantum. Evidence for the adaptive advantage of chloroplast avoidance movements in plant survival has also been found. Additional discoveries include mechano-stress-induced chloroplast movement in ferns and mosses, and microtubule-mediated chloroplast movement in the moss Physcomitrella. The possible ecological significance of chloroplast movement is discussed in the final part of this review.

  6. 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

  7. Air mass 1.5 global and direct solar simulation and secondary reference cell calibration using a filtered large area pulsed solar simulator

    NASA Technical Reports Server (NTRS)

    Mueller, Robert L.

    1985-01-01

    Spectral mismatch between a solar simulator and a desired spectrum can result in nearly 20 percent measurement error in the output of photovoltaic devices. This occurs when a crystalline silicon cell monitors the intensity of an unfiltered large area pulsed solar simulator (LAPSS) simulating the ASTM air mass 1.5 direct spectrum and the test device is amorphous silicon. The LAPSS spectral irradiance is modified with readily available glass UV filters to closely match either the ASTM air mass 1.5 direct or global spectrum. Measurement error is reduced to about 1 percent when using either filter if the reference cell and test device are the same general type.

  8. 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.

  9. Polycyclic aromatic hydrocarbons in air on small spatial and temporal scales - II. Mass size distributions and gas-particle partitioning

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Klánová, Jana; Ilić, Predrag; Kohoutek, Jiří; Gasić, Bojan; Kovacić, Igor; Škrdlíková, Lenka

    2010-12-01

    Polycyclic aromatic hydrocarbons (PAHs) were measured together with inorganic air pollutants at two urban sites and one rural background site in the Banja Luka area, Bosnia and Hercegovina, during 72 h in July 2008 using a high time resolution (5 samples per day) with the aim to study gas-particle partitioning, aerosol mass size distributions and to explore the potential of a higher time resolution (4 h-sampling). In the particulate phase the mass median diameters of the PAHs were found almost exclusively in the accumulation mode (0.1-1.0 μm of size). These were larger for semivolatile PAHs than for non-volatile PAHs. Gas-particle partitioning of semivolatile PAHs was strongly influenced by temperature. The results suggest that the Junge-Pankow model is inadequate to explain the inter-species variation and another process must be significant for phase partitioning which is less temperature sensitive than adsorption. Care should be taken when interpreting slopes m of plots of the type log K p = m log p L0 + b based on 24 h means, as these are found sensitive to the time averaging, i.e. tend to be higher than when based on 12 h-mean samples.

  10. 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

  11. 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.

  12. PMF receptor modelling of fine and coarse PM 10 in air masses governing monsoon conditions in Hanoi, northern Vietnam

    NASA Astrophysics Data System (ADS)

    Hien, P. D.; Bac, V. T.; Thinh, N. T. H.

    Fine and coarse PM 10 samples collected in Hanoi in 1999-2001 were analysed for black carbon (BC) and water soluble ions (WSI) and measured data were disaggregated according to three types of back trajectories, namely (1) northerly, over inland China, (2) northeasterly, over East China Sea and, (3) southwesterly over Indochina peninsula. Trajectories of types 1, 2 and 3 prevail in September/October-December, January-March/April and May-August, respectively. A source-receptor modelling was performed for each type of trajectories individually using the Positive Matrix Factorisation (PMF) technique. Six or seven sources were extracted for each trajectory type, including soil dust, primary and secondary emissions from local burning (LB), vehicle/road dust, sea salt, Cl-depleted marine aerosols and long-range transport (LRT). LRT contributes little to the coarse mass, but accounts for 50%, 34% and 33% of the fine mass in trajectories of types 1, 2 and 3, respectively. More than two-thirds of the fine mode sulphate are attributed to LRT and associated with ammonium. The comparison of LRT and LB source profiles suggests that air masses arriving from north-northeasterly trajectories are more polluted than those coming from the southwest. Therefore the contribution of LRT's aerosols further enhances the seasonal contrast in the particulate concentration with maximum in winter and minimum in summer. Various mechanisms of sulphate formation in LRT and LB were suggested based on the concentration ratios of [SO 42-]/[K +], [SO 42-]/[BC] and [NH 4+]/[SO 42-] for the two sources.

  13. 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.

  14. Biomass Burning versus Fossil Fuel Combustion Signatures of Air Masses Transported from Asia to the U.S. West Coast during ITCT2k2

    NASA Astrophysics Data System (ADS)

    de Gouw, J.; Cooper, O.; Warneke, C.; Hudson, P.; Brock, C.; Fehsenfeld, F.; Holloway, J.; Huebler, G.; Murphy, D.; Nowak, J.; Parrish, D.; Ryerson, T.; Trainer, M.; Atlas, E.

    2003-12-01

    The goal of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT2k2) was to study the transport of air pollution from Asia across the Pacific Ocean, and the implications for the background atmospheric composition at the surface in North America. During research flights of the NOAA WP-3 research aircraft on May 5 and 17, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia in the free troposphere to North America. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on May 5, 17 and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) versus propane (C3H8), and the percentage of particles measured by the PALMS (particle analysis by laser mass spectrometry) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast at various latitudes and pressures during the entire ITCT2k2 period, showed that air masses from South-East Asia and China were generally transported at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for South-East Asia. Combined with the origin of the air masses versus altitude determined by the back-trajectories, this explains the measured altitude profiles of the biomass burning indicators.

  15. Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

    NASA Astrophysics Data System (ADS)

    Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

    2011-12-01

    The chemical composition and concentration of aerosols at a certain site can vary depending on season, the air mass source region and distance from sources. Regardless of the environment, new particle formation (NPF) events are one of the major sources for ultrafine particles which are potentially hazardous to human health. Grown particles are optically active and efficient CCN resulting in important implications for visibility and climate (Zhang et al., 2004). The study presented here is intended to provide information about various aspects of continental, urban and marine air masses reflected by wind patterns of the air arriving at the measurement site. Additionally we will be focusing on NPF events associated with different types of air masses affecting their emergence and temporal evolution. Measurements of the ambient aerosol, various trace gases and meteorological parameters were performed within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from mid-November to mid-December 2008 at the atmospheric research station "El Arenosillo" located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean. Number and mass as well as PAH and black carbon concentrations were measured in PM1 and size distribution instruments covered the size range 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (AMS). In order to evaluate the characteristics of different air masses linking local and regional sources as well as NPF processes, characteristic air mass types were classified dependent on backwards trajectory pathways and local meteorology. Large nuclei mode concentrations in the number size distribution were found within continental and urban influenced air mass types due to frequently occurring NPF events. Exploring individual production and sink variables, sulfuric

  16. Satellite-based identification of tropopause folding signatures along air mass boundaries

    NASA Astrophysics Data System (ADS)

    Wimmers, Anthony James

    Tropopause folding is a significant though frequently underestimated source of mass exchange between the stratosphere and the troposphere. Although tropopause folds are inherently three-dimensional phenomena, empirical evidence shows that certain signature features in two-dimensional satellite products that are sensitive to tropopause height can be used to infer the vertical layering that characterizes tropopause folds. Both Altered Water Vapor (AWV) imagery and Total Ozone Mapping Spectrometer (TOMS) total ozone reveal significant gradients at the "openings" of tropopause folds, and the direction of the gradient indicates the direction of the intrusion. This is demonstrated empirically with a comparison of the satellite imagery to a data set of aircraft-based ozone lidar transects from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment. Using the data set to optimize the parameters of this empirical relationship, a statistical model is developed to predict the location of tropopause folds based solely on the properties of AWV imagery, which operates on a hemispheric-scale domain and at the approximately 10-km resolution of the GOES water vapor channel. Validation of this model with evidence of tropopause folding from operational radiosonde data was only partially successful; the validation was not reliable enough to provide precise confirmation of the model parameter values, but it did provide some confirmation that the model was well calibrated. Application of this model over a February to May, 2000 time period provides a four-month "climatology" of tropopause folding activity around North America. During this time period, tropopause folding activity was strongest over the northeast Pacific and northwest Atlantic, and at a minimum in the high latitudes around Hudson Bay. Over the entire domain (25--63° N, 40--165° W), tropopause folding activity was greatest in March. This result does not prove that downward vertical transport from

  17. Multidisciplinary distinction of mass-movement and flood-induced deposits in lacustrine environments: implications for Holocene palaeohydrology and natural hazards (Lake Ledro, Southern Alps, Italy)

    NASA Astrophysics Data System (ADS)

    Simonneau, A.; Chapron, E.; Vannière, B.; Wirth, S. B.; Gilli, A.; Di Giovanni, C.; Anselmetti, F. S.; Desmet, M.; Magny, M.

    2012-08-01

    High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and river-bed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events) in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments are finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events: light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography) of the organic matter occurring in soils, river beds and lacustrine samples together with lake-sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are dense and synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass movements triggered by historical and pre-historical regional earthquakes dated to 2005 AD, 1891 AD, 1045 AD and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11495 cal. yr BP. Dark-coloured sedimentary event are dense and develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and ligno-cellulosic debris) and are interpreted as resulting from intense hyperpycnal flood events. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence and applying the De Ploey erosion model allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 4 mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting

  18. Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards

    NASA Astrophysics Data System (ADS)

    Simonneau, A.; Chapron, E.; Vannière, B.; Wirth, S. B.; Gilli, A.; Di Giovanni, C.; Anselmetti, F. S.; Desmet, M.; Magny, M.

    2013-03-01

    High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and riverbed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events) in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments have been finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events (SEs): light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography) of the organic matter present in soil, riverbed and lacustrine samples together with lake sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass-movements triggered by historical and pre-historical regional earthquakes dated to AD 2005, AD 1891, AD 1045 and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11 495 cal. yr BP. Dark-coloured SEs develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and lignocellulosic debris) and are interpreted as resulting from intense hyperpycnal flood event. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 5 mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting from the combination of heavy rainfall and snowmelt. The recurrence of

  19. Recent trends of persistent organic pollutants in air in central Europe - Air monitoring in combination with air mass trajectory statistics as a tool to study the effectivity of regional chemical policy

    NASA Astrophysics Data System (ADS)

    Dvorská, A.; Lammel, G.; Holoubek, I.

    We use air mass back trajectory analysis of persistent organic pollutant (POP) levels monitored at a regional background site, Košetice, Czech Republic, as a tool to study the effectiveness of emission reduction measures taken in the last decade in the region. The representativity of the chosen trajectory starting height for air sampling near ground was ensured by excluding trajectories starting at time of inversions lower than their starting height. As the relevant pollutant sources are exclusively located in the atmospheric boundary layer, trajectory segments above this layer were also excluded from the analysis. We used a linear time weight to account for the influence of dispersion and deposition on trace components abundances and to quantify the ground source loading, a continuous measure for the influence of surface emissions. Hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), DDT, and two time periods, the years 1997-1999 and 2004-2006, were studied. The pollutant levels transported to Košetice decreased for all substances except HCB. Except for lindane seasonal emissions were insignificant. Increasing emissions of HCB were at least partly linked to the 2002 floods in the Danube basin. Major emissions of 1997-1999 which decreased significantly were in France (lindane), western Poland, Hungary and northern ex-Yugoslavia (technical HCH), and the Czech Republic (DDT). Emissions remaining in 2004-2006 include HCB and DDT in the northern Czech Republic, HCB and PCBs in Germany. Besides changes in emission strength meteorological factors influence the level of transported pollutant concentrations. The prevailing air flow pattern limits the geographic coverage of this analysis to central Europe and parts of western Europe. However, no POP monitoring stations exist in areas suitable for a possible extension of the study area.

  20. Movement - uncoordinated

    MedlinePlus

    Lack of coordination; Loss of coordination; Coordination impairment; Ataxia; Clumsiness; Uncoordinated movement ... are passed through families (such as congenital cerebellar ataxia, Friedreich ataxia , ataxia - telangiectasia , or Wilson disease ) Multiple ...

  1. Validation and Application of the Mass Balance Model To Determine the Effectiveness of Portable Air Purifiers in Removing Ultrafine and Submicrometer Particles in an Apartment.

    PubMed

    Lee, Wan-Chen; Catalano, Paul J; Yoo, Jun Young; Park, Chan Jung; Koutrakis, Petros

    2015-08-18

    We validated the use of the mass balance model to determine the effectiveness of portable air purifiers in removing ultrafine (<0.10 μm) and submicrometer particles (0.10-0.53 μm) in an apartment. We evaluated two identical portable air purifiers, equipped with high efficiency particulate air filters, for their performance under three different air flow settings and three target air exchange rates: 0.60, 0.90, and 1.20 h(-1). We subsequently used a mixed effects model to estimate the slope between the measured and modeled effectiveness by particle size. Our study showed that effectiveness was highly particle size-dependent. For example, at the lowest target air exchange rate, it ranged from 0.33 to 0.56, 0.51 to 0.75, and 0.60 to 0.81 for the three air purifier flow settings, respectively. Our findings suggested that filtration was the dominant removal mechanism for submicrometer particles, whereas deposition could play a more important role in ultrafine particle removal. We found reasonable agreement between measured and modeled effectiveness with size-resolved slopes ranging from 1.11 ± 0.06 to 1.25 ± 0.07 (mean ± SE), except for particles <35 nm. Our study design can be applied to investigate the performances of other portable air purifiers as well as the influences of various parameters on effectiveness in different residential settings.

  2. Air mass origin signals in δ 18O of tree-ring cellulose revealed by back-trajectory modeling at the monsoonal Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Wernicke, Jakob; Hochreuther, Philipp; Grießinger, Jussi; Zhu, Haifeng; Wang, Lily; Bräuning, Achim

    2016-12-01

    A profound consideration of stable oxygen isotope source water origins is a precondition for an unambiguous palaeoenvironmental interpretation of terrestrial δ 18O archives. To stress the influence of air mass origins on widely used δ 18O tree-ring chronologies, we conducted correlation analyses between six annually resolved δ 18O tree-ring cellulose ( δ ^{18}O_{TC}) chronologies and mean annual air package origins obtained from backward trajectory modeling. This novel approach has been tested for a transect at the southeastern Tibetan plateau (TP), where air masses with different isotopic composition overlap. Detailed examinations of daily precipitation amounts and monthly precipitation δ 18O values ( δ ^{18}OP) were conducted with the ERA Interim and Laboratoire de Météorologie Dynamique General Circulation Model (LMDZiso) data, respectively. Particularly the southernmost study sites are influenced by a distinct amount effect. Here, air package origin δ ^{18}O_{TC} relations are generally weaker in contrast to our northern located study sites. We found that tree-ring isotope signatures at dry sites with less rain days per year tend to be influenced stronger by air mass origin than tree-ring isotope values at semi-humid sites. That implies that the local hydroclimate history inferred from δ ^{18}O_{TC} archives is better recorded at semi-humid sites.

  3. 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…

  4. 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 ...

  5. 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

    2015-02-06

    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.

  6. Determination of benzene at trace levels in air by a novel method based on solid-phase microextraction gas chromatography/mass spectrometry.

    PubMed

    Saba, A; Cuzzola, A; Raffaelli, A; Pucci, S; Salvadori, P

    2001-01-01

    A new method for the determination of benzene at trace levels in air is presented. The method consists of the collection of air samples on adsorbent cartridges with simultaneous adsorption of pre-established amounts of D6-labeled internal standard. Desorption from the cartridge is performed by solid-phase microextraction (SPME) with analysis by gas chromatography/mass spectrometry (GC/MS) using an ion trap mass spectrometer. The influence of several parameters (type of SPME fiber, temperature, time, for example) was investigated, and good linearity in the range 10-400 ng of C6D6, with a coefficient of variance (CV) around 3-5%, was obtained. The method was tested by sampling air in a town center in Italy, and a benzene concentration of approximately 50 microg/m(3) was determined. The maximum limit recommended by the European Community is 10 microg/m(3).

  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. 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.

  9. Elemental composition and radical formation potency of PM10 at an urban background station in Germany in relation to origin of air masses

    NASA Astrophysics Data System (ADS)

    Hellack, Bryan; Quass, Ulrich; Beuck, Henning; Wick, Gabriele; Kuttler, Wilhelm; Schins, Roel P. F.; Kuhlbusch, Thomas A. J.

    2015-03-01

    At an urban background station in Mülheim-Styrum, North Rhine Westphalia, Germany, a set of 75 PM10 samples was collected over a one year period, followed by analyses for mass, chemical composition and hydroxyl radical (OHrad) formation potency. Additionally, the origin of air masses for the sampling days was calculated by 48-h backward trajectories, subdivided into the four cardinal sectors. Significant lower PM10 mass concentrations were observed for summertime air masses from the west compared to the other seasons and cardinal sectors. For the OHrad formation potency higher values were detected if air masses originate from east and south, thus predominantly being of continental origin. From the elevated OHrad formation potencies in fall and winter a seasonal trend with low potencies in summers is assumed. Furthermore, source apportionment was performed by a positive matrix factor analysis, separating seven plausible factors which could be attributed to mineral dust, secondary nitrate, industry, non-exhaust traffic, fossil fuel combustion, marine aerosol and secondary aerosol factors. The intrinsic OHrad formation potency was found to be associated mainly with the fossil fuel combustion factor (45%) and industry factor (22%).

  10. Optimization of automated gas sample collection and isotope ratio mass spectrometric analysis of delta(13)C of CO(2) in air.

    PubMed

    Zeeman, Matthias J; Werner, Roland A; Eugster, Werner; Siegwolf, Rolf T W; Wehrle, Günther; Mohn, Joachim; Buchmann, Nina

    2008-12-01

    The application of (13)C/(12)C in ecosystem-scale tracer models for CO(2) in air requires accurate measurements of the mixing ratios and stable isotope ratios of CO(2). To increase measurement reliability and data intercomparability, as well as to shorten analysis times, we have improved an existing field sampling setup with portable air sampling units and developed a laboratory setup for the analysis of the delta(13)C of CO(2) in air by isotope ratio mass spectrometry (IRMS). The changes consist of (a) optimization of sample and standard gas flow paths, (b) additional software configuration, and (c) automation of liquid nitrogen refilling for the cryogenic trap. We achieved a precision better than 0.1 per thousand and an accuracy of 0.11 +/- 0.04 per thousand for the measurement of delta(13)C of CO(2) in air and unattended operation of measurement sequences up to 12 h.

  11. 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;

  12. The Effect of Isotopic Composition on the Uncertainty of Routine Metal Mass Concentration Measurements in Ambient Air

    PubMed Central

    Brown, Richard J. C.; Goddard, Sharon L.; Brown, Andrew S.; Yardley, Rachel E.

    2008-01-01

    The main sources of uncertainty encountered during the analysis of the mass concentration of metals in ambient air as part of the operation of the UK Heavy Metals Monitoring Network are presented. It is observed that the uncertainty contribution from possible variation in the isotopic composition of the sample depends on the element in question, but can be significant (e.g., for Pb, Cd, and Hg). The working curve method for the ICP-MS analysis of metals in solution, with a low resolution, high throughput instrument measuring at one m/z ratio per element, relies on the relative abundance of the isotopes under consideration being the same in both the sample and the calibration solution. Calculation of the uncertainty in this analysis assumes that the isotopic composition variation within the sample and calibration solution is limited to a defined range. Therefore, in order to confirm the validity of this quantification methodology and its uncertainty budget, the isotopic composition of the calibration standards used for quantification has been determined. The results of this analysis are presented here. PMID:19223968

  13. Total ozone seasonal and interannual variations in the principal air masses of the Northern Hemisphere in 1975-1990

    NASA Technical Reports Server (NTRS)

    Karol, Igor L.; Klyagina, L. P.; Shalamyansky, A. M.; Jagovkina, S. V.

    1994-01-01

    The diurnally mean total ozone X from the Northern Hemisphere ground based 90 stations for 1975-1990 are averaged over the Arctic (bar X (sub A)) Intermediate (bar X (sub I)) and Tropical (bar X (sub T)) air mass areas, divided by the jet stream axes on the isobaric surfaces 300 and 200 mb. The mean square variations of the so averaged X are considerably smaller than of the X, averaged over the corresponding zonal belts. This property allows one to improve considerably the statistical significance of X trends and changes over various time periods, taking into account the time correlation of data for adjacent time intervals. Bar X (sub A), bar X (sub I), and bar X (sub T) trends are estimated over the periods of solar activity rise and fall in its 21st and rise in its 22nd 11 year cycles and over the periods of west and east phases of the known over the periods of west and east phases of the known quasibiennial oscillation (QBO). Solar activity variations affect mostly bar X (sub T), bar X (sub I) trends in summer months, while QBO phases influence the X changes mostly during the cold half year. X are lower in the west QBO phase and their trend is negative during almost all periods considered. The anthropogenic effects on the X is also estimated.

  14. Biological soliton in multicellular movement

    NASA Astrophysics Data System (ADS)

    Kuwayama, Hidekazu; Ishida, Shuji

    2013-07-01

    Solitons have been observed in various physical phenomena. Here, we show that the distinct characteristics of solitons are present in the mass cell movement of non-chemotactic mutants of the cellular slime mould Dictyostelium discoideum. During starvation, D. discoideum forms multicellular structures that differentiate into spore or stalk cells and, eventually, a fruiting body. Non-chemotactic mutant cells do not form multicellular structures; however, they do undergo mass cell movement in the form of a pulsatile soliton-like structure (SLS). We also found that SLS induction is mediated by adhesive cell-cell interactions. These observations provide novel insights into the mechanisms of biological solitons in multicellular movement.

  15. Historical and Social Movement: A Search for Boundaries.

    ERIC Educational Resources Information Center

    Smith, Arthur L.

    This paper is a presentation of what a mass movement pressupposes rhetorically, as opposed to what a movement is in social or historical terms. The author outlines the functions of rhetoric in a movement, in order to establish how the metaphor operates as the essential rhetorical instrument. He states that a mass social or historical movement is…

  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. Measurements of δ13C in CH4 and using particle dispersion modeling to characterize sources of Arctic methane within an air mass

    NASA Astrophysics Data System (ADS)

    France, J. L.; Cain, M.; Fisher, R. E.; Lowry, D.; Allen, G.; O'Shea, S. J.; Illingworth, S.; Pyle, J.; Warwick, N.; Jones, B. T.; Gallagher, M. W.; Bower, K.; Le Breton, M.; Percival, C.; Muller, J.; Welpott, A.; Bauguitte, S.; George, C.; Hayman, G. D.; Manning, A. J.; Myhre, C. Lund; Lanoisellé, M.; Nisbet, E. G.

    2016-12-01

    A stratified air mass enriched in methane (CH4) was sampled at 600 m to 2000 m altitude, between the north coast of Norway and Svalbard as part of the Methane in the Arctic: Measurements and Modelling campaign on board the UK's BAe-146-301 Atmospheric Research Aircraft. The approach used here, which combines interpretation of multiple tracers with transport modeling, enables better understanding of the emission sources that contribute to the background mixing ratios of CH4 in the Arctic. Importantly, it allows constraints to be placed on the location and isotopic bulk signature of the emission source(s). Measurements of δ13C in CH4 in whole air samples taken while traversing the air mass identified that the source(s) had a strongly depleted bulk δ13C CH4 isotopic signature of -70 (±2.1)‰. Combined Numerical Atmospheric-dispersion Modeling Environment and inventory analysis indicates that the air mass was recently in the planetary boundary layer over northwest Russia and the Barents Sea, with the likely dominant source of methane being from wetlands in that region.

  18. The quantification of carbon dioxide in humid air and exhaled breath by selected ion flow tube mass spectrometry.

    PubMed

    Smith, David; Pysanenko, Andriy; Spanel, Patrik

    2009-05-01

    The reactions of carbon dioxide, CO(2), with the precursor ions used for selected ion flow tube mass spectrometry, SIFT-MS, analyses, viz. H(3)O(+), NO(+) and O(2) (+), are so slow that the presence of CO(2) in exhaled breath has, until recently, not had to be accounted for in SIFT-MS analyses of breath. This has, however, to be accounted for in the analysis of acetaldehyde in breath, because an overlap occurs of the monohydrate of protonated acetaldehyde and the weakly bound adduct ion, H(3)O(+)CO(2), formed by the slow association reaction of the precursor ion H(3)O(+) with CO(2) molecules. The understanding of the kinetics of formation and the loss rates of the relevant ions gained from experimentation using the new generation of more sensitive SIFT-MS instruments now allows accurate quantification of CO(2) in breath using the level of the H(3)O(+)CO(2) adduct ion. However, this is complicated by the rapid reaction of H(3)O(+)CO(2) with water vapour molecules, H(2)O, that are in abundance in exhaled breath. Thus, a study has been carried out of the formation of this adduct ion by the slow three-body association reaction of H(3)O(+) with CO(2) and its rapid loss in the two-body reaction with H(2)O molecules. It is seen that the signal level of the H(3)O(+)CO(2) adduct ion is sensitively dependent on the humidity (H(2)O concentration) of the sample to be analysed and a functional form of this dependence has been obtained. This has resulted in an appropriate extension of the SIFT-MS software and kinetics library that allows accurate measurement of CO(2) levels in air samples, ranging from very low percentage levels (0.03% typical of tropospheric air) to the 6% level that is about the upper limit in exhaled breath. Thus, the level of CO(2) can be traced through single time exhalation cycles along with that of water vapour, also close to the 6% level, and of trace gas metabolites that are present at only a few parts-per-billion. This has added a further dimension to

  19. 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

    2015-02-07

    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

  20. Quantitative comparison of a flared and a standard heated metal capillary inlet with a voltage-assisted air amplifier on an electrospray ionization linear ion trap mass spectrometer.

    PubMed

    Dixon, R Brent; Muddiman, David C

    2007-01-01

    The performance characteristics (i.e., ion abundance and electrospray ion current) of a flared and blunt-ended heated metal capillary were evaluated with a voltage-assisted air amplifier on a linear ion trap mass spectrometer (LTQ-MS). The results demonstrated that a standard capillary afforded higher ion abundance than a flared capillary, thus further work is necessary to investigate conditions for which significant benefits with the flared capillary will be observed. The compatibility of a voltage-assisted air amplifier is explored for both types of capillaries and in all cases resulted in improved ion abundance and spray current.

  1. Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds

    USGS Publications Warehouse

    Weiser, Emily; Lanctot, Richard B.; Brown, Stephen C.; Alves, Jose A.; Battley, Phil F.; Bentzen, Rebecca L.; Bety, Joel; Bishop, Mary Anne; Boldenow, Megan; Bollache, Loic; Casler, Bruce; Christie, Maureen; Coleman, Jonathan T.; Conklin, Jesse R.; English, Willow B.; Gates, H. River; Gilg, Olivier; Giroux, Marie-Andree; Gosbell, Ken; Hassell, Chris J.; Helmericks, Jim; Johnson, Andrew; Katrinardottir, Borgny; Koivula, Kari; Kwon, Eunbi; Lamarre, Jean-Francois; Lang, Johannes; Lank, David B.; Lecomte, Nicolas; Liebezeit, Joseph R.; Loverti, Vanessa; McKinnon, Laura; Minton, Clive; Mizrahi, David S.; Nol, Erica; Pakanen, Veli-Matti; Perz, Johanna; Porter, Ron; Rausch, Jennie; Reneerkens, Jeroen; Ronka, Nelli; Saalfeld, Sarah T.; Senner, Nathan R.; Sittler, Benoit; Smith, Paul A.; Sowl, Kristine M.; Taylor, Audrey; Ward, David H.; Yezerinac, Stephen; Sandercock, Brett K.

    2016-01-01

    Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional markers. Investigators could maximize recovery of tags by strategically deploying geolocators on males, previously marked individuals, and successful breeders, though targeting subsets of a population could bias the resulting migratory movement data in some species.

  2. Chloroplast movement.

    PubMed

    Wada, Masamitsu

    2013-09-01

    Chloroplast movement is important for plant survival under high light and for efficient photosynthesis under low light. This review introduces recent knowledge on chloroplast movement and shows how to analyze the responses and the moving mechanisms, potentially inspiring research in this field. Avoidance from the strong light is mediated by blue light receptor phototropin 2 (phot2) plausibly localized on the chloroplast envelop and accumulation at the week light-irradiated area is mediated by phot1 and phot2 localized on the plasma membrane. Chloroplasts move by chloroplast actin (cp-actin) filaments that must be polymerized by Chloroplast Unusual Positioning1 (CHUP1) at the front side of moving chloroplast. To understand the signal transduction pathways and the mechanism of chloroplast movement, that is, from light capture to motive force-generating mechanism, various methods should be employed based on the various aspects. Observation of chloroplast distribution pattern under different light condition by fixed cell sectioning is somewhat an old-fashioned technique but the most basic and important way. However, most importantly, precise chloroplast behavior during and just after the induction of chloroplast movement by partial cell irradiation using an irradiator with either low light or strong light microbeam should be recorded by time lapse photographs under infrared light and analyzed. Recently various factors involved in chloroplast movement, such as cp-actin filaments and CHUP1, could be traced in Arabidopsis transgenic lines with fluorescent protein tags under a confocal laser scanning microscope (CLSM) and/or a total internal reflection fluorescence microscope (TIRFM). These methods are listed and their advantages and disadvantages are evaluated.

  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. Interlaboratory evaluation of trace element determination in workplace air filter samples by inductively coupled plasma mass spectrometry†‡

    PubMed Central

    Shulman, Stanley A.; Brisson, Michael J.; Howe, Alan M.

    2015-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is becoming more widely used for trace elemental analysis in the occupational hygiene field, and consequently new ICP-MS international standard procedures have been promulgated by ASTM International and ISO. However, there is a dearth of interlaboratory performance data for this analytical methodology. In an effort to fill this data void, an interlaboratory evaluation of ICP-MS for determining trace elements in workplace air samples was conducted, towards fulfillment of method validation requirements for international voluntary consensus standard test methods. The study was performed in accordance with applicable statistical procedures for investigating interlaboratory precision. The evaluation was carried out using certified 37-mm diameter mixed-cellulose ester (MCE) filters that were fortified with 21 elements of concern in occupational hygiene. Elements were spiked at levels ranging from 0.025 to 10 μg filter−1, with three different filter loadings denoted “Low”, “Medium” and “High”. Participating laboratories were recruited from a pool of over fifty invitees; ultimately twenty laboratories from Europe, North America and Asia submitted results. Triplicates of each certified filter with elemental contents at three different levels, plus media blanks spiked with reagent, were conveyed to each volunteer laboratory. Each participant was also provided a copy of the test method which each participant was asked to follow; spiking levels were unknown to the participants. The laboratories were requested to prepare the filters by one of three sample preparation procedures, i.e., hotplate digestion, microwave digestion or hot block extraction, which were described in the test method. Participants were then asked to analyze aliquots of the prepared samples by ICP-MS, and to report their data in units of μg filter−1. Most interlaboratory precision estimates were acceptable for medium- and high

  5. Retrieval of vertical columns of sulfur dioxide from SCIAMACHY and OMI: Air mass factor algorithm development, validation, and error analysis

    NASA Astrophysics Data System (ADS)

    Lee, Chulkyu; Martin, Randall V.; van Donkelaar, Aaron; O'Byrne, Gray; Krotkov, Nickolay; Richter, Andreas; Huey, L. Gregory; Holloway, John S.

    2009-11-01

    We develop an improved retrieval of sulfur dioxide (SO2) vertical columns from two satellite instruments (SCIAMACHY and OMI) that measure ultraviolet solar backscatter. For each SCIAMACHY and OMI observation, a local air mass factor (AMF) algorithm converts line-of-sight "slant" columns to vertical columns using altitude-dependent scattering weights computed with a radiative transfer model (LIDORT), weighted by relative vertical SO2 profile (shape factor) determined locally with a global atmospheric chemistry model (GEOS-Chem). The scattering weights account for viewing geometry, surface albedo, cloud scattering, absorption by ozone, and scattering and absorption by aerosols. Absorption of radiation by mineral dust can reduce seasonal mean instrument sensitivity by 50%. Mean SO2 shape factors 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 with coincident airborne in situ measurements (INTEX-A, INTEX-B, and a campaign over east China). The annual mean AMF errors are estimated to be 35-70% in polluted regions (e.g., East Asia and the eastern United States) and less than 10% over clear ocean regions. The overall SO2 error assessment is 45-80% for yearly averages over 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 United States (r = 0.85 for SCIAMACHY and 0.82 for OMI). A sensitivity study confirms the sensitivity of SCIAMACHY and OMI to anthropogenic SO2 emissions.

  6. sup 222 Rn, sup 222 Rn progeny and sup 220 Rn progeny as atmospheric tracers of air masses at the Mauno Loa Observatory

    SciTech Connect

    Hutter, A.R.; George, A.C.; Maiello, M.L.; Fisenne, I.M.; Larsen, R.J.; Beck, H.L.; Wilson, F.C.

    1990-03-01

    {sup 222}Rn, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations in air were measured at the Mauna Loa Observatory (MLO) in Hawaii during March 1989 in order to investigate the feasibility of using them as atmospheric tracers to help determine local air mass flow patterns. Charcoal traps, cooled to dry ice temperatures, were used to collect {sup 222}Rn, which was subsequently measured in pulse ionization chambers at the Environmental Measurements Laboratory (EML). {sup 222}Rn progeny and {sup 220}Rn progeny for 37 samples were measured at the Observatory by sampling high volumes of air through filters, which were counted for up to 11 h in alpha scintillation counters. Individual progeny concentrations were calculated using both least squares and maximum likelihood techniques. In general, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations were low when free tropospheric air was present (downslope and tradewind conditions), and consistently higher when surface air from the island broke through the trade wind inversion layer (upslope conditions). The data suggest that {sup 222}Rn, {sup 222}Rn progeny, or {sup 220}Rn progeny monitoring may provide new and useful information to help indicate the different air flow patterns present at MLO. 17 refs., 5 figs., 2 tabs.

  7. 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.

  8. 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.

  9. Characterizing the chemical evolution of air masses via multi-platform measurements of volatile organic compounds (VOCs) during CalNEX: Composition, OH reactivity, and potential SOA formation

    NASA Astrophysics Data System (ADS)

    Gilman, J. B.; Kuster, W. C.; Bon, D.; Warneke, C.; Lerner, B. M.; Williams, E. J.; Holloway, J. S.; Pollack, I. B.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Herndon, S. C.; Zahniser, M. S.; Vlasenko, A. L.; Li, S.; Alvarez, S. L.; Rappenglueck, B.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; De Gouw, J. A.

    2011-12-01

    Volatile organic compounds (VOCs) are critical components in the photochemical production of ozone (O3) and secondary organic aerosol (SOA). During the CalNex 2010 field campaign, an extensive set of VOCs were measured at the Pasadena ground site, and aboard the NOAA WP-3D aircraft and the WHOI Research Vessel Atlantis. The measurements from each platform provide a unique perspective into the emissions, transport, and atmospheric processing of VOCs within the South Coast Air Basin (SoCAB). The observed enhancement ratios of the hydrocarbons measured on all three platforms are in good agreement and are generally well correlated with carbon monoxide (CO), indicating the prevalence of on-road VOC emission sources throughout the SoCAB. Offshore measurements aboard the ship and aircraft are used to characterize the air mass composition as a function of the land/sea-breeze effect. VOC ratios and other trace gases are used to identify air masses containing relatively fresh emissions that were often associated with offshore flow and re-circulated continental air associated with onshore flow conditions. With the prevailing southwesterly airflow pattern in the LAB throughout the daytime, the Pasadena ground site effectively functions as a receptor site and is used to characterize primary VOC emissions from downtown Los Angeles and to identify the corresponding secondary oxidation products. The chemical evolution of air masses as a function of the time of day is investigated in order to determine the relative impacts of primary emissions vs. secondary VOC products on OH reactivity and potential SOA formation. The reactivity of VOCs with the hydroxyl radical (OH) at the Pasadena site was dominated by the light hydrocarbons, isoprene, and oxygenated VOCs including aldehydes (secondary products) and alcohols (primary anthropogenic emissions). Toluene and benzaldehyde, both of which are associated with primary anthropogenic emissions, are the predominant VOC precursors to the

  10. Measurement of the mass energy-absorption coefficient of air for x-rays in the range from 3 to 60 keV.

    PubMed

    Buhr, H; Büermann, L; Gerlach, M; Krumrey, M; Rabus, H

    2012-12-21

    For the first time the absolute photon mass energy-absorption coefficient of air in the energy range of 10 to 60 keV has been measured with relative standard uncertainties below 1%, considerably smaller than those of up to 2% assumed for calculated data. For monochromatized synchrotron radiation from the electron storage ring BESSY II both the radiant power and the fraction of power deposited in dry air were measured using a cryogenic electrical substitution radiometer and a free air ionization chamber, respectively. The measured absorption coefficients were compared with state-of-the art calculations and showed an average deviation of 2% from calculations by Seltzer. However, they agree within 1% with data calculated earlier by Hubbell. In the course of this work, an improvement of the data analysis of a previous experimental determination of the mass energy-absorption coefficient of air in the range of 3 to 10 keV was found to be possible and corrected values of this preceding study are given.

  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. Inertial Mass

    ERIC Educational Resources Information Center

    King, Kenneth P.

    2007-01-01

    The inertial balance is one device that can help students to quantify the quality of inertia--a body's resistance to a change in movement--in more generally understood terms of mass. In this hands-on activity, students use the inertial balance to develop a more quantitative idea of what mass means in an inertial sense. The activity also helps…

  13. 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.

  14. Measurement of the x-ray mass energy-absorption coefficient of air using 3 keV to 10 keV synchrotron radiation.

    PubMed

    Büermann, L; Grosswendt, B; Kramer, H-M; Selbach, H-J; Gerlach, M; Hoffmann, M; Krumrey, M

    2006-10-21

    For the first time absolute photon mass energy-absorption coefficients of air in the energy range 3 keV to 10 keV have been measured with relative standard uncertainties less than 1%, significantly smaller than those of up to 5% assumed hitherto for calculated data. Monochromatized synchrotron radiation was used to measure both the total radiant energy by means of silicon photodiodes calibrated against a cryogenic radiometer and the fraction of radiant energy that is deposited in dry air by means of a free air ionization chamber. The measured ionization charge was converted into energy absorbed in air by calculated effective W values of photons as a function of their energy based on new measurements of the W values in dry air for electron kinetic energies between 1 keV and 7 keV, also presented in this work. The measured absorption coefficients were compared with state-of-the art calculations and found to agree within 0.7% with data calculated earlier by Hubbell at energies above 4 keV but were found to differ by values up to 2.1% at 10 keV from more recent calculations of Seltzer.

  15. 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

  16. 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

  17. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    PubMed Central

    Amos-Abanyie, S.; Akuffo, F. O.; Kutin-Sanwu, V.

    2013-01-01

    Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+) simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT). An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses. PMID:23878528

  18. Variation in airborne (134)Cs, (137)Cs, particulate (131)I and (7)Be maximum activities at high-altitude European locations after the arrival of Fukushima-labeled air masses.

    PubMed

    Masson, Olivier; Bieringer, Jacqueline; Brattich, Erika; Dalheimer, Axel; Estier, Sybille; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Steinmann, Philipp; Tositti, Laura; Van Beek, Pieter; Vismes-Ott, Anne de

    2016-10-01

    The Fukushima-labeled air mass arrival, and later the cesium-134 ((134)Cs), cesium-137 ((137)Cs) and particulate iodine-131 (hereafter noted (131)Ip) maximum levels were registered in Europe at different dates depending on the location. Most of those data were obtained at low-altitude sampling areas. Here, we compare the airborne levels registered at different high-altitude European locations (from 850 m to about 3500 m). The integrated (137)Cs activity concentration was not uniform with regard to the altitude even after a long travel time/distance from Japan. Moreover, the relation of integrated (137)Cs vs. altitude showed a linear decrease up to an altitude of about 3000 m. A similar trend was noticed for (131)Ip (particulate fraction) while it increased above 3000 m. Comparison with (7)Be activity concentration showed that, as far as the high altitude location is concerned, the (137)Cs and (134)Cs maximum concentrations corresponded to the (7)Be maximum, suggesting downdraft movements from high tropospheric or stratospheric layers to be responsible for (137,134)Cs increase and peak values. This was also confirmed by high potential vorticity and low relative humidity registered during the peak values.

  19. Detection of Free Tropospheric Air Masses With High So2 and Aerosol Concentrations: Evidence For New Aerosol Particle Formation By H2so4/h2o Nucleation

    NASA Astrophysics Data System (ADS)

    Katragkou, E.; Wilhelm, S.; Kiendler, A.; Arnold, F.; Minikin, A.; Schlager, H.; van Velthoven, P.

    Sulfur dioxide and aerosol measurements were performed in the free troposphere (FT) and the Planetary Boundary Layer (PBL) above continental Europe. The measure- ments took place on board of the German research aircraft "Falcon" in 18 April 2001 as a part of the SCAVEX campaign. A novel aircraft based CIMS (Chemical Ion- ization Mass Spectrometry) instrument equipped with an ion trap mass spectrometer (ITMS) with a low detection limit (50pptv) and a high time resolution (1.3s) operated by MPI-K was used to perform the SO2 measurements. For the aerosol measurements DLR-IPA operated a Condensation Particle Size Analyzer, detecting particles with diameters d > 4, 7, 9 and 20nm and a PCASP-100X aerosol spectrometer probe (d > 100nm). In the measurements made mostly around 5000m altitude SO2 rich air masses were occasionally observed with SO2 VMR of up to 2900pptv. The strong SO2 pollu- tion was due to fast vertical transport of polluted continental PBL air and small-scale deep convection, as indicated by the 5-day backward 3D trajectories. These observa- tions of strong SO2 pollution have interesting implications for aerosol processes, in- cluding efficient formation of gaseous sulfuric acid (GSA) and new aerosol particles. They also imply fast growth of freshly nucleated aerosol particles, which increases the chance for new particles to grow to the size of a CCN. Our analysis indicates the occurrence of new particle formation by H2SO4/H2O nucleation and fast new particle growth by H2SO4/H2O condensation and self-coagulation in the different air masses encountered during the flight.

  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. Seasonal origins of air masses transported to Mount Wrangell, Alaska, and comparison with the past atmospheric dust and tritium variations in its ice core

    NASA Astrophysics Data System (ADS)

    Yasunari, T. J.; Shiraiwa, T.; Kanamori, S.; Fujii, Y.; Igarashi, M.; Yamazaki, K.; Benson, C. S.; Hondoh, T.

    2006-12-01

    The North Pacific region is subject to various climatic phenomena such as the Pacific Decadal Oscillation (PDO), the El Niño-Southern Oscillation (ENSO), and the Arctic Oscillation (AO), significantly affecting the ocean and the atmosphere. Additionally, material circulation is also very active in this region such as spring dust storms in the desert and arid regions of East Asia and forest fires in Siberia and Alaska. Understanding the complex connections among the climatic phenomena and the material circulation would help in attempts to predict future climate changes. For this subject, we drilled a 50-m ice core at the summit of Mount Wrangell, which is located near the coast of Alaska (62°162'170"162°171'N, 144°162'170"162;°171'W, and 4100-m). We analyzed dust particle number density, tritium concentration, and 171 171 171 171 170 162 171 D in the core. The ice core spanned the years from 1992 to 2002 and we finally divided the years into five parts (early-spring; late-spring; summer; fall; winter). Dust and tritium amounts varied annually and intra-annually. For further understanding of the factors on those variations, we should know the origins of the seasonal dust and tritium. Hence, we examined their origins by the calculation of everyday 10-days backward trajectory analysis from January 1992 to August 2002 with 3-D wind data of the European Center for Medium-Range Weather Forecast (ECMWF). In early spring, the air mass from East Asia increased and it also explained dust increases in springtime, although the air contribution in winter increased too. In late spring, the air mass from the stratosphere increased, and it also corresponded to the stratospheric tritium increase in the ice core. The air masses from Siberia and the North Pacific in the mid-latitude always significantly contributed to Mount Wrangell, although those maximum contributions were fall and summer, respectively. The air mass originating in the interior of Alaska and North America did

  2. Observation of the transport of polluted air masses from the northeastern United States to Cape Sable Island, Nova Scotia, Canada, during the 1993 NARE summer intensive

    NASA Astrophysics Data System (ADS)

    Knapp, K. G.; Balsley, B. B.; Jensen, M. L.; Hanson, H. P.; Birks, J. W.

    1998-06-01

    Vertical profiles of ozone, temperature, pressure, and water vapor mass mixing ratio obtained using a parafoil kite platform during the North Atlantic Regional Experiment (NARE) 1993 summer intensive at Cape Sable Island, Nova Scotia, Canada, demonstrate the of use of kite platforms for the collection of vertically and temporally resolved data over a fixed location. During the period August 8-28, 1993, 39 profiles of the lower atmosphere were collected. Data collected as part of this field campaign illustrate the complex vertical stratification and temporal variability of pollutants transported into the Maritime Provinces of Canada. Transport phenomena resulted in pollution events in which ozone at the ground level remained in the 20-40 parts per billion by volume (ppbv) range, while mixing ratios of 90-130 ppbv were observed above ˜300 m. Back trajectories indicate that these highly elevated levels of ozone are attributable to source regions in the heavily industrialized northeastern United States. Vertical stratification of the lower atmosphere was also present during transport of Canadian air to the sampling site, with layers of both elevated and diminished ozone observed, while marine air did not exhibit layering characteristic of air masses originating from continental source regions.

  3. Development of a thermal desorption gas chromatography-mass spectrometry method for quantitative determination of haloanisoles and halophenols in wineries' ambient air.

    PubMed

    Camino-Sánchez, F J; Ruiz-García, J; Zafra-Gómez, A

    2013-08-30

    An analytical method for the detection and quantification of haloanisoles and their corresponding halophenols in wineries' ambient air was developed. The target analytes were haloanisoles and halophenols, reported by previous scientific literature as responsible for wine taint. A calibrated pump and active tubes filled with Tenax GR™ were used for sampling. These tubes were thermally desorbed and analyzed using gas chromatography-triple quadrupole mass spectrometry in the selected reaction monitoring mode. The adsorption efficiencies of five commercial sampling tubes filled with different materials were evaluated. The efficiencies of the selected adsorbent were close to 100% for all sampled compounds. Desorption, chromatographic and mass spectrometric conditions were accurately optimized allowing very low limits of quantification and wide linear ranges. The limits of quantification in ambient air ranged from 0.8pgtube(-1) for 2,4,6-trichlorophenol, to 28pgtube(-1) for pentachlorophenol. These results are of great importance because human sensory threshold for haloanisoles is very low. The chromatographic method was also validated and the instrumental precision and trueness were established, a maximum RSD of 9% and a mean recovery of 91-106% were obtained. The proposed method involves an easy and sensitive technique for the early detection of haloanisoles and their precursor halophenols in ambient air avoiding contamination of wine or winery facilities.

  4. Ambient air particle transport into the effluent of a cold atmospheric-pressure argon plasma jet investigated by molecular beam mass spectrometry

    NASA Astrophysics Data System (ADS)

    Dünnbier, M.; Schmidt-Bleker, A.; Winter, J.; Wolfram, M.; Hippler, R.; Weltmann, K.-D.; Reuter, S.

    2013-10-01

    Ambient air species, which are transported into the active effluent of an atmospheric-pressure plasma jet result in highly reactive oxygen and nitrogen species (RONS). Especially for the envisaged application field of plasma medicine, these RONS are responsible for strong biological responses. In this work, the effect of ambient air transport into the effluent of an atmospheric-pressure plasma argon jet on the on-axis densities of nitrogen, oxygen and argon was investigated by means of absolutely calibrated molecular beam mass spectrometry (MBMS). According to biomedical experiments a (bottomless) Petri dish was installed in front of the MBMS. In the following, the near flow field is referring to the region close to the nozzle exit and the far flow field is referring to the region beyond that. The absolute on-axis densities were obtained by three different methods, for the near flow field with VUV-absorption technique, for the far flow field with the MBMS and the total flow field was calculated with a computational fluid dynamics (CFD) simulation. The results of the ambient air particle densities of all independent methods were compared and showed an excellent agreement. Therefore the transport processes of ambient air species can be measured for the whole effluent of an atmospheric-pressure plasma jet. Additionally, with the validation of the simulation it is possible in future to calculate the ambient species transport for various gas fluxes in the same turbulent flow regime. Comparing the on-axis densities obtained with an ignited and with a non-ignited plasma jet shows that for the investigated parameters, the main influence on the ambient air species transport is due to the increased temperature in the case when the jet is switched on. Moreover, the presence of positive ions (e.g. ArN_{2}^{+} ) formed due to the interaction of plasma-produced particles and ambient air species, which are transported into the effluent, is shown.

  5. 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.

  6. 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.

  7. Movements, dive patterns, and social associations of short-finned pilot whales, Globicephala macrorhynchus, released from a mass stranding in the Florida keys

    USGS Publications Warehouse

    Wells, Randall S.; Fougeres, Erin M.; Cooper, Arthur G.; Stevens, Robert O.; Brodsky, Micah; Lingenfelser, Robert; Dold, Chris; Douglas, David C.

    2013-01-01

    Short-finned pilot whales (Globicephala macrorhynchus) are among the most common cetaceans to engage in mass strandings in the southeastern United States. Because these are primarily pelagic, continental shelf-edge animals, much of what is known about this species has derived from mass stranding events. Post-release monitoring via satellite-linked telemetry was conducted with two adult males determined on-site to be healthy, and released directly from a mass stranding of 23 pilot whales in May 2011, near Cudjoe Key, Florida. Tracking provided an opportunity to evaluate the decision for immediate release vs rehabilitation, and to learn more about the lives of members of this difficult-to-study species in the wild. The two pilot whales remained together for at least 16 d before transmissions from one pilot whale (Y-404) ceased. Dive patterns and travel rates suggested that Y-404’s condition deteriorated prior to signal loss. Pilot Whale Y-400 was tracked for another 51 d, moving from the Blake Plateau to the Greater Antilles, remaining in the Windward Passage east of Cuba for the last 17 d of tracking. Once he reached the Antilles, Y-400 remained in high-relief habitat appropriate for the species and made dives within or exceeding the reported range for depth and duration for this species, following expected diel patterns, presumably reflecting continued good health. Telemetry data indicate that he made at least one dive to 1,000 to 1,500 m, and several dives lasted more than 40 min. Although the fates of the two released pilot whales may have been different, the concept of evaluating health and releasing individuals determined to be healthy at the time of stranding appears to have merit as an alternative to bringing all members of mass-stranded pilot whale groups into rehabilitation.

  8. A mass-balance approach for assessing PCB movement during remediation of a PCB-contaminated deposit on the Fox River, Wisconsin

    USGS Publications Warehouse

    Steuer, Jeffrey J.

    2000-01-01

    The U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, collected water samples during the September 1 - December 15, 1999 removal of sediment contaminated with polychlorinated biphenyls (PCBs) from a reach of the Lower Fox River designated Sediment Management Unit (SMU) 56/57. Results of analyses of the samples, along with monitoring activities of several other organizations, were used to delineate and compare PCB mass pathways during the cleanup effort (fig. 1). Results indicate that the cleanup at SMU 56/57 had the following effect on PCB mass: dredging permanently removed more than 650 kg (1441 lb) of PCBs, transported 14.5 kg (32 lb) downstream, and volatilized 2.6 kg (5.7 lb) to the atmosphere; associated activities on the shore returned 0.1 kg (0.3 lb) to the river. This report documents the USGS data-collection efforts and details the mass-balance approach for PCB pathway delineation.

  9. The Differential Effect of Arm Movements during Gait on the Forward Acceleration of the Centre of Mass in Children with Cerebral Palsy and Typically Developing Children

    PubMed Central

    Meyns, Pieter; Molenaers, Guy; Duysens, Jacques; Jonkers, Ilse

    2017-01-01

    Background: We aimed to study the contribution of upper limb movements to propulsion during walking in typically developing (TD) children (n = 5) and children with hemiplegic and diplegic cerebral palsy (CP; n = 5 and n = 4, respectively). Methods: Using integrated three-dimensional motion capture data and a scaled generic musculoskeletal model that included upper limbs, we generated torque driven simulations of gait in OpenSim. Induced acceleration analyses were then used to determine the contributions of the individual actuators located at the relevant degrees of freedoms of the upper and lower limb joints to the forward acceleration of the COM at each time point of the gait simulation. The mean values of the contribution of the actuators of upper limbs, lower limbs, and gravity in different phases of the gait cycle were compared between the three groups. Findings: The results indicated a limited contribution of the upper limb actuators to COM forward acceleration compared to the contribution of lower limbs and gravity, in the three groups. In diplegic CP, the contribution of the upper limbs seemed larger compared to TD during the preswing and swing phases of gait. In hemiplegic CP, the unaffected arm seemed to contribute more to COM deceleration during (pre)swing, while the affected side contributed to COM acceleration. Interpretation: These findings suggest that in the presence of lower limb dysfunction, the contribution of the upper limbs to forward propulsion is altered, although they remain negligible compared to the lower limbs and gravity. PMID:28298890

  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

    2014-05-06

    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. Improved detection of low vapor pressure compounds in air by serial combination of single-sided membrane introduction with fiber introduction mass spectrometry (SS-MIMS-FIMS).

    PubMed

    Cotte-Rodríguez, Ismael; Handberg, Eric; Noll, Robert J; Kilgour, David P A; Cooks, R Graham

    2005-05-01

    The use of two methods in tandem, single-sided membrane introduction mass spectrometry (SS-MIMS) and fiber introduction mass spectrometry (FIMS), is presented as a technique for field analysis. The combined SS-MIMS-FIMS technique was employed in both a modified commercial mass spectrometer and a miniature mass spectrometer for the selective preconcentration of the explosive simulant o-nitrotoluene (ONT) and the chemical warfare agent simulant, methyl salicylate (MeS), in air. A home-built FIMS inlet was fabricated to allow introduction of the solid-phase microextraction (SPME) fiber into the mass spectrometer chamber and subsequent desorption of the trapped compounds using resistive heating. The SS-MIMS preconcentration system was also home-built from commercial vacuum parts. Optimization experiments were done separately for each preconcentration system to achieve the best extraction conditions prior to use of the two techniques in combination. Improved limits of detection, in the low ppb range, were observed for the combination compared to FIMS alone, using several SS-MIMS preconcentration cycles. The SS-MIMS-FIMS response for both instruments was found to be linear over the range 50 to 800 ppb. Other parameters studied were absorption time profiles, effects of sample flow rate, desorption temperature, fiber background, memory effects, and membrane fatigue. This simple, sensitive, accurate, robust, selective, and rapid sample preconcentration and introduction technique shows promise for field analysis of low vapor pressure compounds, where analyte concentrations will be extremely low and the compounds are difficult to extract from a matrix like air.

  12. The patient movement as an emancipation movement

    PubMed Central

    Williamson, Charlotte

    2008-01-01

    Abstract Objective  To suggest that the patient movement is an emancipation movement. Background  The patient movement is young and fragmented; and it can seem confusing because it lacks an explicit ideology with intellectual and theoretical underpinnings. Methods  Drawing mainly on the experiences and the published writings of patient activists, the author identified eight aspects of the patient movement that could be compared with aspects of recognized emancipation movements: the radicalization of activists; the creation of new knowledge; the identification of guiding principles; the sense of direction; the unmasking of new issues; schisms within the movement and allies outside it; and the gradual social acceptance of some of the ideas (here standards of health care) that activists work to promote. Results  Similarities between certain aspects of the patient movement and of the recognized emancipation movements were close. Conclusion  The patient movement can be regarded as an emancipation movement, albeit an immature one. PMID:18494955

  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. 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.

  15. 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

  16. 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.

  17. The Impact of Mass Movement and Fluid Flow during Ridge Subduction inferred from Physical Properties and Zeolite Assemblage in the Upper Plate Slope of the Costa Rica Subduction Zone

    NASA Astrophysics Data System (ADS)

    Hamahashi, M.; Screaton, E.; Tanikawa, W.; Hashimoto, Y.; Martin, K. M.; Saito, S.; Kimura, G.

    2015-12-01

    The Costa Rica subduction zone offshore Osa Peninsula is known as an erosive margin with active seismicity and the subduction of the Cocos Ridge. One of the major unknowns in this margin is the nature of the unconformity at the base of the slope sediments in the upper plate and the high velocity materials below. To investigate the geologic processes across the unconformity, we examined the consolidation state and mineral assemblages of the sediments at the mid-slope Site 1380 drilled during IODP Expedition 344 by conducting microstructural observation, particle size analysis, X-ray fluorescence/diffraction analysis and resistivity measurement. The general compaction trend is controlled primarily by grain-size sorting and the physical property transition is likely caused by massive sediment removal under normal fault regime, thickness of which range between ~600-850 m determined from the composite porosity-depth curve. Across the unconformity between the late Pliocene~late Pleistocene silty clay (Unit 1) and late Pliocene~early Pleistocene clayey siltstone (Unit 2), the mineral/element components of the sediments is marked by the transitions in zeolite compositions; Unit 1 consists of laumontite and heulandite, whereas below the unconformity, Unit 2 sediments contain analcime, laumontite, and heulandite, but laumontite become less abundant at lower depth. The experienced temperature of the sediments in Unit 2 is estimated to have reached between ~86 and 122℃ as inferred from analcime burial diagenesis. This may correspond with the greater depth range prior to mass movement and normal faulting. The initial analcime burial diagenetic zone was likely cut off by the sediment removal across the unconformity, and later overprinted by high temperature fluid along the boundary forming laumontite and heulandite in the vicinity. These results illustrate that ridge subduction has substantial potential to cause mass movement, an extensional stress regime, and fluid flow from

  18. 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.

  19. Design and preliminary tests of a blade tip air mass injection system for vortex modification and possible noise reduction on a full-scale helicopter rotor

    NASA Technical Reports Server (NTRS)

    Pegg, R. J.; Hosier, R. N.; Balcerak, J. C.; Johnson, H. K.

    1975-01-01

    Full-scale tests were conducted on the Langley helicopter rotor test facility as part of a study to evaluate the effectiveness of a turbulent blade tip air mass injection system in alleviating the impulsive noise (blade slap) caused by blade-vortex interaction. Although blade-slap conditions could not be induced during these tests, qualitative results from flow visualization studies using smoke showed that the differential velocity between the jet velocity and the rotor tip speed was a primary parameter controlling the vortex modification.

  20. Early Holocene (8.6 ka) rock avalanche deposits, Obernberg valley (Eastern Alps): Landform interpretation and kinematics of rapid mass movement

    PubMed Central

    Ostermann, Marc; Sanders, Diethard; Ivy-Ochs, Susan; Alfimov, Vasily; Rockenschaub, Manfred; Römer, Alexander

    2012-01-01

    In the Obernberg valley, the Eastern Alps, landforms recently interpreted as moraines are re-interpreted as rock avalanche deposits. The catastrophic slope failure involved an initial rock volume of about 45 million m³, with a runout of 7.2 km over a total vertical distance of 1330 m (fahrböschung 10°). 36Cl surface-exposure dating of boulders of the avalanche mass indicates an event age of 8.6 ± 0.6 ka. A 14C age of 7785 ± 190 cal yr BP of a palaeosoil within an alluvial fan downlapping the rock avalanche is consistent with the event age. The distal 2 km of the rock-avalanche deposit is characterized by a highly regular array of transverse ridges that were previously interpreted as terminal moraines of Late-Glacial. ‘Jigsaw-puzzle structure’ of gravel to boulder-size clasts in the ridges and a matrix of cataclastic gouge indicate a rock avalanche origin. For a wide altitude range the avalanche deposit is preserved, and the event age of mass-wasting precludes both runout over glacial ice and subsequent glacial overprint. The regularly arrayed transverse ridges thus were formed during freezing of the rock avalanche deposits. PMID:24966447

  1. Early Holocene (8.6 ka) rock avalanche deposits, Obernberg valley (Eastern Alps): Landform interpretation and kinematics of rapid mass movement.

    PubMed

    Ostermann, Marc; Sanders, Diethard; Ivy-Ochs, Susan; Alfimov, Vasily; Rockenschaub, Manfred; Römer, Alexander

    2012-10-15

    In the Obernberg valley, the Eastern Alps, landforms recently interpreted as moraines are re-interpreted as rock avalanche deposits. The catastrophic slope failure involved an initial rock volume of about 45 million m³, with a runout of 7.2 km over a total vertical distance of 1330 m (fahrböschung 10°). (36)Cl surface-exposure dating of boulders of the avalanche mass indicates an event age of 8.6 ± 0.6 ka. A (14)C age of 7785 ± 190 cal yr BP of a palaeosoil within an alluvial fan downlapping the rock avalanche is consistent with the event age. The distal 2 km of the rock-avalanche deposit is characterized by a highly regular array of transverse ridges that were previously interpreted as terminal moraines of Late-Glacial. 'Jigsaw-puzzle structure' of gravel to boulder-size clasts in the ridges and a matrix of cataclastic gouge indicate a rock avalanche origin. For a wide altitude range the avalanche deposit is preserved, and the event age of mass-wasting precludes both runout over glacial ice and subsequent glacial overprint. The regularly arrayed transverse ridges thus were formed during freezing of the rock avalanche deposits.

  2. 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...

  3. 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...

  4. 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

  5. Ports Primer: 7.2 Air Emissions

    EPA Pesticide Factsheets

    Near-port communities are often disproportionately impacted by air emissions due to port operations, goods movement operations and other industries that may be co-located with ports. Air emissions at ports also impact regional air quality.

  6. On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory

    SciTech Connect

    Arsene, N.; Rebel, H.; Sima, O.

    2012-11-20

    In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

  7. Indications of photochemical histories of Pacific air masses from measurements of atmospheric trace species at Point Arena, California

    NASA Technical Reports Server (NTRS)

    Parrish, D. D.; Hahn, C. J.; Williams, E. J.; Norton, R. B.; Fehsenfeld, F. C.; Singh, H. B.; Shetter, J. D.; Gandrud, B. W.; Ridley, B. A.

    1992-01-01

    Measurements were made of a suite of photochemically active trace species (including light hydrocarbons, ozone, peroxyacetyl nitrate, HNO3, NO3(-), NO(x), and NO(y)) in marine air collected during a 10-day period in April and May 1985 at Point Arena (California), a coastal inflow site. It was found that the mixing ratios of the alkanes, ozone, peroxyacetyl nitrate, and HNO3 correlated with variations in the origins of calculated air parcel trajectories and with variations in the ratios of the light alkanes. The highest levels of alkanes and the photochemical products were found in parcels that had been rapidly transported across the North Pacific Ocean from near the 600-mbar level above the east Asian coast. It is suggested that production over the continents, transport to the marine areas, and parallel removal processes account for much of the observed correlation.

  8. 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

  9. Occupational Exposure to Cobalt and Tungsten in the Swedish Hard Metal Industry: Air Concentrations of Particle Mass, Number, and Surface Area.

    PubMed

    Klasson, Maria; Bryngelsson, Ing-Liss; Pettersson, Carin; Husby, Bente; Arvidsson, Helena; Westberg, Håkan

    2016-07-01

    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 µm(2)·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 number

  10. Desert dust aerosol air mass mapping in the western Sahara, using particle properties derived from space-based multi-angle imaging

    NASA Astrophysics Data System (ADS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Müller, Detlef; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

    2009-02-01

    ABSTRACT 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 suborbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05-0.1. 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 (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

  11. 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.

  12. Desert Dust Aerosol 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; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Mueller, Detlef; 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 suborbital aerosol measurements into the satellite s larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 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 (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

  13. Determination of volatile organic compounds in urban and industrial air from Tarragona by thermal desorption and gas chromatography-mass spectrometry.

    PubMed

    Ras-Mallorquí, Maria Rosa; Marcé-Recasens, Rosa Maria; Borrull-Ballarín, Francesc

    2007-05-15

    This study describes the optimisation of an analytical method to determine 54 volatile organic compounds (VOCs) in air samples by active collection on multisorbent tubes, followed by thermal desorption and gas chromatography-mass spectrometry. Two multisorbent beds, Carbograph 1/Carboxen 1000 and Tenax/Carbograph 1TD, were tested. The latter gave better results, mainly in terms of the peaks that appeared in blank chromatograms. Temperatures, times and flow desorption were optimised. Recoveries were higher than 98.9%, except methylene dichloride, for which the recovery was 74.9%. The method's detection limits were between 0.01 and 1.25mugm(-3) for a volume sample of 1200ml, and the repeatability on analysis of 100ng of VOCs, expressed as relative standard deviation for n=3, was lower than 4% for all compounds. Urban and industrial air samples from the Tarragona region were analysed. Benzene, toluene, ethylbenzene and xylenes (BTEX) were found to be the most abundant VOCs in urban air. Total VOCs in urban samples ranged between 18 and 307mugm(-3). Methylene chloride, 1,4-dichlorobenzene, chloroform and styrene were the most abundant VOCs in industrial samples, and total VOCs ranged between 19 and 85mugm(-3).

  14. 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.

  15. 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.

  16. 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.

  17. Quantification of the sources and composition of particulate matter by field-deployable mass spectrometry: implications for air quality and public health.

    PubMed

    Hayes, Patrick L

    2017-02-27

    Airborne particulate matter less than 2.5 μm in diameter (PM2.5) negatively impacts air quality in cities throughout the world where it has been linked to increased cardiac and respiratory morbidity and mortality. For this reason PM2.5 standards have been established by many countries and the World Health Organization. However, these guidelines are regularly exceeded in North America, Europe and East Asia. While PM2.5 is often reported as a single atmospheric species, it is actually a mixture of organic and inorganic compounds. The organic fraction, termed organic aerosol (OA), contributes approximately 20-70% of the PM2.5 mass globally, and OA itself is a complex mixture of thousands of compounds. Characterizing the chemical properties of OA represents a major analytical challenge that has motivated the development of a range of new instruments. The focus of this perspective is the use of field-deployable mass spectrometers and in particular the Aerodyne Aerosol Mass Spectrometer (AMS) for chemically characterizing submicron particles. Field measurements of the composition of PM2.5 are directly relevant to evaluating its health impact because reductions in life expectancy due to PM2.5 vary according to composition. In addition, AMS measurements are especially useful for characterizing OA. The sources of OA are not well understood as evidenced by the performance of many air quality models, including those run by government agencies, which lack accurate and well constrained parameterizations for simulating secondary OA concentrations in urban regions. Given that OA is an important component of the total PM2.5 mass, this uncertainty makes accurate evaluation of the impact of PM2.5 on public health difficult, especially when evaluating future mitigation strategies. The development of the AMS has been a critical step towards addressing this public health challenge in that it provides quantitative data regarding particulate matter and OA concentration and composition

  18. Tracking surface water mass movements in the Southwest Pacific for the last 5,000 years: Perspectives from deep-sea corals

    NASA Astrophysics Data System (ADS)

    Komugabe, A. F.; Fallon, S.; Thresher, R.; Eggins, S. M.

    2013-12-01

    Current understanding of present-day natural climate variability can be improved by obtaining a good baseline through investigating past variability during the Holocene (11,500 cal yr B.P. to the present). In particular, changes in marine reservoir radiocarbon ages through the Holocene can provide information on regional ocean circulation. In the southwest Pacific, little is known about the variability of reservoir ages during this period. This limits efforts to reconstruct Southern Hemisphere Ocean and atmospheric circulation over this period. Here we present mid- to late-Holocene reservoir ages for the southwest Pacific. Reservoir ages were calculated using coupled uranium series (MC ICPMS) and radiocarbon (AMS) measurements on deep-sea (200 - 1000m) black coral (Anthozoa, Antipatharia) collected live from the Tasman Sea. Black corals have enormous potential as environmental archives to provide valuable long-term, high-resolution records. We confirm that black corals are slow growing (typical radial growth rate is 0.005 mm/yr) and extremely long-lived (maximum age 5,823 × 41 years), making them excellent candidates for proxies to extend environmental records into the Holocene. Our results also indicate comparatively lower reservoir ages for the mid-Holocene than present day for the south Tasman Sea. The lower reservoir ages in the mid-Holocene reflect a greater influx of well-equilibrated warm water of sub-tropical origin into this region, as well as increased stratification. During the late Holocene in the north Tasman, the average reservoir age between 1790 and 1900 was ˜330 years, followed by a steep decrease over time of about 70 years to 1950 AD (our most modern value). This indicates an increase in surface ocean ventilation of water masses in this region. These results are consistent with observational and modeling studies for the last century, which show significant changes in regional circulation and suggest these changes started as early as the 17th

  19. 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)

  20. 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.

  1. Movement - unpredictable or jerky

    MedlinePlus

    ... uncontrolled); Hyperkinetic movements References Jankovic J, Lang AE. Movement disorders. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta ... Elsevier Saunders; 2012:chap 21. Lang AE. Other movement disorders. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  2. Relationship between maternal pre‐pregnancy body mass index, gestational weight gain and childhood fatness at 6–7 years by air displacement plethysmography

    PubMed Central

    Santos, Iná S.; Matijasevich, Alicia

    2015-01-01

    Abstract This study aims to investigate the effect of maternal pre‐pregnancy body mass index (BMI) and gestational weight gain (GWG) on offspring body composition. In this prospective cohort study, offspring body composition at 6 years of age was obtained through air displacement plethysmography. Linear regression was used to obtain crude and adjusted coefficients. Information regarding offspring body composition and maternal pre‐pregnancy BMI was available for 3156 children and on offspring body composition and GWG for 3129 children. There was a direct association of maternal pre‐pregnancy BMI and GWG with offspring's fat mass (FM), fat‐free mass (FFM), fat mass index (FMI), fat‐free mass index (FFMI) and body fat percent (BF%) in crude and adjusted analyses. After adjustment for co‐variables, for each kg m−2 of maternal pre‐pregnancy BMI increase, there was a mean increment of 0.13 kg in the offspring FFM, 0.06 kg m−2 in FFMI, 0.11 kg in FM, 0.07 kg m−2 in FMI and 0.18% in BF%. For each kilogram of maternal GWG increase, there was a mean increment of 0.08 kg in offspring's FM, 0.05 kg m−2 in FMI, 0.04 kg in FFM, 0.01 kg m−2 in FFMI and 0.18 % in BF%. Mothers with a higher pre‐pregnancy BMI or GWG tend to have children with greater adiposity at age 6 years. Fetal overnutrition is more likely among mothers with greater BMI during pregnancy; as a consequence, it can accelerate the childhood obesity epidemic. PMID:25850519

  3. 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.

  4. 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.

  5. Proton transfer reaction mass spectrometry for the sensitive and rapid real-time detection of solid high explosives in air and water.

    PubMed

    Jürschik, S; Sulzer, P; Petersson, F; Mayhew, C A; Jordan, A; Agarwal, B; Haidacher, S; Seehauser, H; Becker, K; Märk, T D

    2010-12-01

    Relying on recent developments in proton transfer reaction mass spectrometry (PTR-MS), we demonstrate here the capability of detecting solid explosives in air and in water in real time. Two different proton transfer reaction mass spectrometers have been used in this study. One is the PTR-TOF 8000, which has an enhanced mass resolution (m/Δm up to 8,000) and high sensitivity (~50 cps/ppbv). The second is the high-sensitivity PTR-MS, which has an improved limit of detection of about several hundreds of parts per quadrillion by volume and is coupled with a direct aqueous injection device. These instruments have been successfully used to identify and monitor the solid explosive 2,4,6-trinitrotoluene (TNT) by analysing on the one hand the headspace above small quantities of samples at room temperature and from trace quantities not visible to the naked eye placed on surfaces (also demonstrating the usefulness of a simple pre-concentration and thermal desorption technique) and by analysing on the other hand trace compounds in water down to a level of about 100 pptw. The ability to identify even minute amounts of threat compounds, such as explosives, particularly within a complex chemical environment, is vital to the fight against crime and terrorism and is of paramount importance for the appraisal of the fate and harmful effects of TNT at marine ammunition dumping sites and the detection of buried antipersonnel and antitank landmines.

  6. Estimation of air-water gas exchange coefficient in a shallow lagoon based on 222Rn mass balance.

    PubMed

    Cockenpot, S; Claude, C; Radakovitch, O

    2015-05-01

    The radon-222 mass balance is now commonly used to quantify water fluxes due to Submarine Groundwater Discharge (SGD) in coastal areas. One of the main loss terms of this mass balance, the radon evasion to the atmosphere, is based on empirical equations. This term is generally estimated using one among the many empirical equations describing the gas transfer velocity as a function of wind speed that have been proposed in the literature. These equations were, however, mainly obtained from areas of deep water and may be less appropriate for shallow areas. Here, we calculate the radon mass balance for a windy shallow coastal lagoon (mean depth of 6m and surface area of 1.55*10(8) m(2)) and use these data to estimate the radon loss to the atmosphere and the corresponding gas transfer velocity. We present new equations, adapted to our shallow water body, to express the gas transfer velocity as a function of wind speed at 10 m height (wind range from 2 to 12.5 m/s). When compared with those from the literature, these equations fit particularly well with the one of Kremer et al. (2003). Finally, we emphasize that some gas transfer exchange may always occur, even for conditions without wind.

  7. Turbulent mass flux closure modeling for variable density turbulence in the wake of an air-entraining transom stern

    NASA Astrophysics Data System (ADS)

    Hendrickson, Kelli; Yue, Dick

    2016-11-01

    This work presents the development and a priori testing of closure models for the incompressible highly-variable density turbulent (IHVDT) flow in the near wake region of a transom stern. This complex, three-dimensional flow includes three regions with distinctly different flow behavior: (i) the convergent corner waves that originate from the body and collide on the ship center plane; (ii) the "rooster tail" that forms from the collision; and (iii) the diverging wave train. The characteristics of these regions involve violent free-surface flows and breaking waves with significant turbulent mass flux (TMF) at Atwood number At = (ρ2 -ρ1) / (ρ2 +ρ1) 1 for which there is little guidance in turbulence closure modeling for the momentum and scalar transport along the wake. Utilizing datasets from high-resolution simulations of the near wake of a canonical three-dimensional transom stern using conservative Volume-of-Fluid (cVOF), implicit Large Eddy Simulation (iLES), and Boundary Data Immersion Method (BDIM), we develop explicit algebraic turbulent mass flux closure models that incorporate the most relevant physical processes. Performance of these models in predicting the turbulent mass flux in all three regions of the wake will be presented. Office of Naval Research.

  8. 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

  9. Evidence from catch-up growth and hoarding behavior of rats that exposure to hypobaric air lowers the body-mass set point.

    PubMed

    Bozzini, Carlos E; Lezón, Christian E; Norese, María F; Conti, María I; Martínez, María P; Olivera, María I; Alippi, Rosa M

    2005-01-01

    The depression of body growth rate and the reduction of body mass for chronological age and gender in growing experimental animals exposed to hypobaric air (simulated high altitude = SHA) have been associated with hypophagia because of reduced appetite. Catch-up growth during protein recovery after a short period of protein restriction only occurs if food intake becomes super-normal, which should not be possible under hypoxic conditions if the set-point for appetite is adjusted by the level of SHA. The present investigation was designed to test the hypothesis that growth retardation during exposure to SHA is due to an alteration of the neural mechanism for setting body mass size rather than a primary alteration of the central set-point for appetite. One group of female rats aged 35 d were exposed to SHA (5460m) in a SHA chamber for 27 d (HX rats). Other group was maintained under local barometric pressure conditions (NX rats). One half of both NX and HX rats were fed a protein-free diet for the initial 9 d of the experimental period. From this time on, they were fed a diet containing 20% protein, as were the remaining rats of both groups during the entire experimental period. The growth rates of both mass and length of the body were significantly depressed in well-nourished rats exposed to SHA during the entire observation period when compared to normoxic ones. At its end, body mass and body length were 24% and 21% less in HX than in NX rats. Growth rates were negatively affected by protein restriction in both NX and HX rats. During protein recovery, they reached supernormal values in response to supernormal levels of energy intake that allowed a complete catch-up of both body mass and length. The finding that energy intake during the period of protein rehabilitation in HX rats previously stunted by protein restriction was markedly higher than in HX control ones at equal levels of hypoxia demonstrates that the degree of hypoxia does not determine directly the

  10. Remote sensing observations for monitoring and mathematical simulations of transboundary air pollutants migration from Siberian mass wildfires to Kazakhstan

    NASA Astrophysics Data System (ADS)

    Kaipov, I. V.

    2017-03-01

    Anthropogenic and natural factors have increased the power of wildfires in massive Siberian woodlands. As a consequence, the expansion of burned areas and increase in the duration of the forest fire season have led to the release of significant amounts of gases and aerosols. Therefore, it is important to understand the impact of wildland fires on air quality, atmospheric composition, climate and accurately describe the distribution of combustion products in time and space. The most effective research tool is the regional hydrodynamic model of the atmosphere, coupled with the model of pollutants transport and chemical interaction. Taking into account the meteorological parameters and processes of chemical interaction of impurities, complex use of remote sensing techniques for monitoring massive forest fires and mathematical modeling of long-range transport of pollutants in the atmosphere, allow to evaluate spatial and temporal scale of the phenomenon and calculate the quantitative characteristics of pollutants depending on the height and distance of migration.

  11. 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, Narong

    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 ~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 ~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 of signal for even the most

  12. Time-of-flight secondary ion mass spectroscopy with bismuth primary ions of clean and air-exposed surfaces of tellurium.

    PubMed

    Trzyna, Malgorzata; Berchenko, Nicolas; Rading, Derk; Cebulski, Jozef

    2014-01-01

    The regularity of Bi(+), Bi(3+) and Bi(3++) primary ions in the time- of-flight secondary ion mass spectroscopy fragment pattern of air oxidized Te and Bi(+) direct-current scan cleaned Te is discussed. The most intensive fragments for a cleaned Te surface are positive and negative Tex and BiTex clusters. The sequence of secondary ion cluster formation is Bi-Te alloying followed by sputtering and ionization. For oxidized Te the chemical composition of the produced TexOy fragments satisfies the relation y=2x for positive fragments and y=2x+1 for negative ones. Experimental findings are in a good agreement with the results predicted by Plog's model for TeO2.

  13. 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

    NASA Astrophysics Data System (ADS)

    Jin, Xinfang; Zhao, Xuan; Huang, Kevin

    2015-04-01

    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 (JMAK) 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 H2/H2O-concentration across various components of the battery are also systematically investigated.

  14. 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.

  15. 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.

  16. Application of proton-transfer-reaction mass spectrometry to the assessment of odorant removal in a biological air cleaner for pig production.

    PubMed

    Hansen, Michael J; Liu, Dezhao; Guldberg, Lise Bonne; Feilberg, Anders

    2012-03-14

    There is an urgent need to develop odor reduction technologies for animal production facilities, and this requires a reliable measurement technique for estimating the removal of odorants. The purpose of the present experiment was to investigate the application of proton-transfer-reaction mass spectrometry (PTR-MS) for continuous measurements at a biofilter from SKOV A/S installed at a pig production facility. PTR-MS was able to handle the harsh conditions with high humidity and dust load in a biofilter and provide reliable data for the removal of odorants, including the highly odorous sulfur compounds. The biofilter removed 80-99% of carboxylic acids, aldehydes, ketones, phenols, and indoles and ca. 75% of hydrogen sulfide. However, only ~0-15% of methanethiol and dimethyl sulfide was removed. In conclusion, PTR-MS is a promising tool that can be used to improve the development of biological air cleaning and other odor reduction technologies toward significant odorants.

  17. Photochemistry of the indoor air pollutant acetone on Degussa P25 TiO2 studied by chemical ionization mass spectrometry.

    PubMed

    Schmidt, Catherine M; Buchbinder, Avram M; Weitz, Eric; Geiger, Franz M

    2007-12-20

    We have used chemical ionization mass spectrometry (CIMS) to study the adsorption and photochemistry of several oxygenated organic species adsorbed to Degussa P25 TiO2, an inexpensive catalyst that can be used to mineralize volatile organic compounds. The molecules examined in this work include the common indoor air pollutant acetone and several of its homologs and possible oxidation and condensation products that may be formed during the adsorption and/or photocatalytic degradation of acetone on titanium dioxide catalysts. We report nonreactive uptake coefficients for acetone, formic acid, acetic acid, mesityl oxide, and diacetone alcohol, and results from photochemical studies that quantify, on a per-molecule basis, the room-temperature photocatalytic conversion of the species under investigation to CO2 and related oxidation products. The data presented here imply that catalytic surfaces that enhance formate and acetate production from acetone precursors will facilitate the photocatalytic remediation of acetone in indoor environments, even at room temperature.

  18. 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.

  19. 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

  20. 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.

  1. Measurement of toxic volatile organic compounds in indoor air of semiconductor foundries using multisorbent adsorption/thermal desorption coupled with gas chromatography-mass spectrometry.

    PubMed

    Wu, Chien-Hou; Lin, Ming-Nan; Feng, Chien-Tai; Yang, Kuang-Ling; Lo, Yu-Shiu; Lo, Jiunn-Guang

    2003-05-09

    A method for the qualitative and quantitative analysis of volatile organic compounds (VOCs) in the air of class-100 clean rooms at semiconductor fabrication facilities was developed. Air samples from two semiconductor factories were collected each hour on multisorbent tubes (including Carbopack B, Carbopack C, and Carbosieve SIII) with a 24-h automatic active sampling system and analyzed using adsorption/thermal desorption coupled with gas chromatography-mass spectrometry. Experimental parameters, including thermal desorption temperature, desorption time, and cryofocusing temperature, were optimized. The average recoveries and the method detection limits for the target compounds were in the range 94-101% and 0.31-0.89 ppb, respectively, under the conditions of a 1 L sampling volume and 80% relative humidity. VOCs such as acetone, isopropyl alcohol, 2-heptanone, and toluene, which are commonly used in the semiconductor and electronics industries, were detected and accurately quantified with the established method. Temporal variations of the analyte concentrations observed were attributed to the improper use of organic solvents during operation.

  2. Molecular characterisation of organic material in air fine particles (PM10) using conventional and reactive pyrolysis-gas chromatography-mass spectrometry.

    PubMed

    Fabbri, Daniele; Prati, Silvia; Vassura, Ivano

    2002-04-01

    Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to study the composition of organic constituents in air particulate matter (PM10) collected inside an industrial area. A few milligrams of sampling filters containing air particles were pyrolysed at 700 degrees C directly (conventional) or after the addition of a derivatising reagent (tetramethylammonium hydroxide, TMAH, for pyrolysis-methylation; hexamethyldisilazane, HMDS, for pyrolysis-silylation). Py-GC-MS was also applied to synthetic polymers (poly(styrene-co-isoprene), polylimonene and polypinene) and vegetation samples (coniferous pollen, bark and resin) to identify markers indicative of possible precursors. Pyrolysates of PM10 showed the same suite of compounds in all the four seasons, dominated by hydrocarbons like styrene, limonene and clusters of isomeric alkenes with 14, 15 and 16 carbon atoms. Pyrolysis products of natural origin, including furaldehyde, benzeneacetonitrile, dehydroabietin and other diterpenoids were found, while no specific markers of synthetic rubbers were detected. The principal products released from reactive pyrolysis of PM10 were methyl or trimethylsilyl (TMS) derivatives of 1,6-anhydroglucose (levoglucosan), fatty acids, dehydroabietic acid and other resin acids along with hydroxy (di)carboxylic acids. Possible sources of the detected products (e.g. pine forest, biomass combustion) are discussed.

  3. Movement disorders and sleep.

    PubMed

    Driver-Dunckley, Erika D; Adler, Charles H

    2012-11-01

    This article summarizes what is currently known about sleep disturbances in several movement disorders including Parkinson disease, essential tremor, parkinsonism, dystonia, Huntington disease, myoclonus, and ataxias. There is an association between movement disorders and sleep. In some cases the prevalence of sleep disorders is much higher in patients with movement disorder, such as rapid eye movement sleep behavior disorder in Parkinson disease. In other cases, sleep difficulties worsen the involuntary movements. In many cases the medications used to treat patients with movement disorder disturb sleep or cause daytime sleepiness. The importance of discussing sleep issues in patients with movement disorders cannot be underestimated.

  4. 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

  5. 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.

  6. Design, Modeling, Fabrication, and Evaluation of the Air Amplifier for Improved Detection of Biomolecules by Electrospray Ionization Mass Spectrometry.

    PubMed

    Robichaud, Guillaume; Dixon, R Brent; Potturi, Amarnatha S; Cassidy, Dan; Edwards, Jack R; Sohn, Alex; Dow, Thomas A; Muddiman, David C

    2011-03-01

    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).

  7. Carbon dioxide emissions from international air freight

    NASA Astrophysics Data System (ADS)

    Howitt, Oliver J. A.; Carruthers, Michael A.; Smith, Inga J.; Rodger, Craig J.

    2011-12-01

    Greenhouse gas emissions from international air transport were excluded from reduction targets under the Kyoto Protocol, partly because of difficulties with quantifying and apportioning such emissions. Although there has been a great deal of recent research into calculating emissions from aeroplane operations globally, publicly available emissions factors for air freight emissions are scarce. This paper presents a methodology to calculate the amount of fuel burnt and the resulting CO 2 emissions from New Zealand's internationally air freighted imports and exports in 2007. This methodology could be applied to other nations and/or regions. Using data on fuel uplift, air freight and air craft movements, and assumptions on mean passenger loadings and the mass of passengers and air freight, CO 2 emissions factors of 0.82 kg CO 2 per t-km and 0.69 kg CO 2 per t-km for short-haul and long-haul journeys, respectively, were calculated. The total amount of fuel consumed for the international air transport of New Zealand's imports and exports was calculated to be 0.21 Mt and 0.17 Mt respectively, with corresponding CO 2 emissions of 0.67 Mt and 0.53 Mt.

  8. 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

  9. Analysis of air-mass modification over Poland and Romania by means of multiwavelength lidars - a case study 19-21/07/2014

    NASA Astrophysics Data System (ADS)

    Costa-Surós, Montserrat; Stachlewska, Iwona S.; Nicolae, Doina; Nemuc, Anca; Janicka, Lucja; Markowicz, Krzysztof M.; Belegante, Livio; Talianu, Camelia; Heese, Birgit; Engelmann, Ronny

    2015-04-01

    A case study of air-mass modification over Poland and Romania, assessing the role of the Carpathian Mountains, during 19-21/07/2014 is analyzed. The study is based mainly on measurements taken by two multiwavelength Raman lidars at two different sites: the Radiative Transfer Laboratory (RT-Lab) at the Faculty of Physics of the University of Warsaw in Warsaw (Poland) and at the RADO site of the National Institute of R&D in Optoelectronics in Magurele (Romania). These data were complemented with meteorological data collected at two other sites: SolarAOT in Strzyżów (Poland) - equipped also with AERONET photometer and CHM15k ceilometer, and in Cluj (Romania). The RADO site, with its 7-wavelength aerosol-Raman-depolarization lidar (RALi) is integrated into EARLINET network. The RT-Lab site, with its 8-wavelength aerosol-Raman-depolarization (PollyXT-type) lidar, started the procedure to join in EARLINET last year. Moreover, RT-Lab and SolarAOT sites are part of the Poland AOD network. The analysis is focused on evaluating both multi-wavelength lidar data sets in order to search for similarities and differences in the vertical profiles describing the atmospheric layers above the two stations. Accordingly to GDAS Hysplit 4-days backward trajectory ending up in Magurele at 0.5, 1.5 and 3 km an air-mass from western Europe entered Poland from the north-west on 19/07/2014, descended on the following day over the Poland AOD station in Strzyżów, followed by Cluj and end up at Magurele on 21/07/2014. As the four stations are located along a north-west to south-east line the objective was to evaluate the aerosol properties of the air flow transported over Poland and further to Romania. At both sites, backscatter profiles at 355, 532 and 1064nm, extinction profiles at 355 and 532nm, and depolarization profiles at 532nm and 355nm, show distinctly layered structure in the atmosphere. Along with these we used data from stations in Strzyżów and Cluj as well as information

  10. Modelling Mass Movements for Planetary Studies

    NASA Technical Reports Server (NTRS)

    Bulmer, M. H.; Glaze, L.; Barnouin-Jha, O.; Murphy, W.; Neumann, G.

    2002-01-01

    Use of an empirical model in conjunction with data from the Chaos Jumbles rock avalanches constrain to first order their flow behavior, and provide a method to interpret rock/debris avalanche emplacement on Mars. Additional information is contained in the original extended abstract.

  11. Topographic Effects on Geologic Mass Movements

    NASA Technical Reports Server (NTRS)

    Baloga, Stephen M.; Frey, Herbert (Technical Monitor)

    2000-01-01

    This report describes research directed toward understanding the response of volcanic lahars and lava flows to changes in the topography along the path of the flow. We have used a variety of steady-state and time-dependent models of lahars and lava flows to calculate the changes in flow dynamics due to variable topography. These models are based on first-order partial differential equations for the local conservation of volume. A global volume conservation requirement is also imposed to determine the extent of the flow as a function of time and the advance rate. Simulated DEMs have been used in this report.

  12. Biomechanics of foetal movement.

    PubMed

    Nowlan, N C

    2015-01-02

    Foetal movements commence at seven weeks of gestation, with the foetal movement repertoire including twitches, whole body movements, stretches, isolated limb movements, breathing movements, head and neck movements, jaw movements (including yawning, sucking and swallowing) and hiccups by ten weeks of gestational age. There are two key biomechanical aspects to gross foetal movements; the first being that the foetus moves in a dynamically changing constrained physical environment in which the freedom to move becomes increasingly restricted with increasing foetal size and decreasing amniotic fluid. Therefore, the mechanical environment experienced by the foetus affects its ability to move freely. Secondly, the mechanical forces induced by foetal movements are crucial for normal skeletal development, as evidenced by a number of conditions and syndromes for which reduced or abnormal foetal movements are implicated, such as developmental dysplasia of the hip, arthrogryposis and foetal akinesia deformation sequence. This review examines both the biomechanical effects of the physical environment on foetal movements through discussion of intrauterine factors, such as space, foetal positioning and volume of amniotic fluid, and the biomechanical role of gross foetal movements in human skeletal development through investigation of the effects of abnormal movement on the bones and joints. This review also highlights computational simulations of foetal movements that attempt to determine the mechanical forces acting on the foetus as it moves. Finally, avenues for future research into foetal movement biomechanics are highlighted, which have potential impact for a diverse range of fields including foetal medicine, musculoskeletal disorders and tissue engineering.

  13. Understanding the movements of metal whiskers

    NASA Astrophysics Data System (ADS)

    Karpov, V. G.

    2015-06-01

    Metal whiskers often grow across leads of electric equipment causing short circuits and raising significant reliability issues. Their nature remains a mystery after several decades of research. It was observed that metal whiskers exhibit large amplitude movements under gentle air flow or, according to some testimonies, without obvious stimuli. Understanding the physics behind that movements would give additional insights into the nature of metal whiskers. Here, we quantitatively analyze possible mechanisms of the observed movements: (1) minute air currents; (2) Brownian motion due to random bombardments with the air molecules; (3) mechanically caused movements, such as (a) transmitted external vibrations, and (b) torque exerted due to material propagation along curved whiskers (the garden hose instability); (4) time dependent electric fields due to diffusion of ions; and (5) non-equilibrium electric fields making it possible for some whiskers to move. For all these mechanisms, we provide numerical estimates. Our conclusion is that the observed movements are likely due to the air currents or electric recharging caused by external light or similar factors.

  14. Environmental Conservation through the People's Movements in India.

    ERIC Educational Resources Information Center

    Asopa, Sheel K.

    1993-01-01

    Describes three popular environmental campaigns against deforestation in India. Discusses the folk dimension, mass mobilization, and geographic extent of the Chipko Movement; the movement against a government program to plant eucalyptus trees; and the movement to save villages in government-labeled "wastelands." (MDH)

  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. 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

  17. 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).

  18. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  19. Functional Movement Disorder

    MedlinePlus

    ... that controls muscles during contraction and at rest. Electroencephalography (EEG) can correlate the movement and detect any ... that controls muscles during contraction and at rest. Electroencephalography (EEG) can correlate the movement and detect any ...

  20. Eye Movement Disorders

    MedlinePlus

    ... t work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder ... of the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over ...

  1. 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

  2. Predicate Movements in Chinese

    ERIC Educational Resources Information Center

    Shou-hsin, Teng

    1975-01-01

    The movements of such higher predicates as time, locative, and complementation verbs are studied, and Tai's Predicate Placement Constraint is rejected as an incorrect account of predicate movements in Chinese. It is proposed, on the other hand, that there is only leftward movement involving predicates in Chinese. (Author)

  3. Linking Literacy and Movement

    ERIC Educational Resources Information Center

    Pica, Rae

    2010-01-01

    There are many links between literacy and movement. Movement and language are both forms of communication and self-expression. Rhythm is an essential component of both language and movement. While people may think of rhythm primarily in musical terms, there is a rhythm to words and sentences as well. Individuals develop an internal rhythm when…

  4. Eye Movements and Learning.

    ERIC Educational Resources Information Center

    Nesbit, Larry L.

    Research on the use of eye movement indices (such as number of fixations, the average fixation duration, and saccadic movements) as a measure of cognitive processing is reviewed in this paper. Information is provided on the physiology of the eye, computer applications to eye movement study, the influence of stimulus materials and intelligence on…

  5. Volatile organic compounds in air at urban and industrial areas in the Tarragona region by thermal desorption and gas chromatography-mass spectrometry.

    PubMed

    Ras, Maria Rosa; Marcé, Rosa Maria; Borrull, Francesc

    2010-02-01

    Annual trends of a group of 66 volatile organic compounds (VOCs), containing 20 ozone precursors, were the aim of a sampling campaign carried out for a year in air at urban and industrial areas from Tarragona region. VOCs were determined by active collection on multisorbent tubes, followed by thermal desorption and gas chromatography-mass spectrometry. The analytical method was developed and validated, showing good levels of detection and qu