WorldWideScience

Sample records for surface transportation weather

  1. Solute transport predicts scaling of surface reaction rates in porous media: Applications to silicate weathering

    CERN Document Server

    Hunt, Allen G; Ghanbarian, Behzad

    2013-01-01

    We apply our theory of conservative solute transport, based on concepts from percolation theory, directly and without modification to reactive solute transport. This theory has previously been shown to predict the observed range of dispersivity values for conservative solute transport over ten orders of magnitude of length scale. We now show that the temporal dependence derived for the solute velocity accurately predicts the time-dependence for the weathering of silicate minerals over nine orders of magnitude of time scale, while its predicted length dependence agrees with data obtained for reaction rates over five orders of magnitude of length scale. In both cases, it is possible to unify lab and field results. Thus, net reaction rates appear to be limited by solute transport velocities. We suggest the possible relevance of our results to landscape evolution of the earth's terrestrial surface.

  2. Land Surface Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — METAR is the international standard code format for hourly surface weather observations. The acronym roughly translates from French as Aviation Routine Weather...

  3. Uruguay - Surface Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface weather observation forms for 26 stations in Uruguay. Period of record 1896-2005, with two to eight observations per day. Files created through a...

  4. Surface Weather Observations Hourly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard hourly observations taken at Weather Bureau/National Weather Service offices and airports throughout the United States. Hourly observations began during the...

  5. Surface Weather Observing Manuals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Manuals and instructions for taking weather observations. Includes the annual Weather Bureau 'Instructions for Preparing Meteorological Forms...' and early airways...

  6. Geomorphic controls on mineral weathering, elemental transport, and production of mineral surface area in a schist bedrock weathering profile, Piedmont Pennsylvania

    Science.gov (United States)

    Wenell, B.; Yoo, K.; Aufdenkampe, A. K.; Mahoney, J. B.; Lepak, L.

    2013-12-01

    We assess a deep chemical weathering profile in the context of geomorphic evolution in the Laurels Schist, a late proterozoic greenschist formation in the Christina River Basin Critical Zone Observatory located in the Piedmont region in southeastern Pennsylvania. Two 21-meter deep rotosonic drill cores were sampled at the ridge top and footslope positions in a first-order, forested watershed. The top meter was sampled at high-resolution in a soil pit adjacent to each drill core and along a hillslope transect to assess geomorphic controls on the weathering profile. Weathering processes in soil and saprolite were examined by observing changes in mineralogy, including the emergence of secondary phyllosilicate and oxide minerals; measuring specific surface area of bulk soil and saprolite; and by quantifying elemental mass changes of major and minor rock-forming elements. Mineral profiles were assessed using clay and bulk XRD, and reveal that kaolinite, a common secondary phyllosilicate, is present above 1.5 meters in the weathering profile. Specific surface area (SSA) values decrease with increasing depth to a critical depth around 2 meters, where the values of untreated (carbon-loaded) and muffled (carbon removed by heating) mineral grains converge to baseline SSA values below 10 m2g-1, indicating that carbon is sorbed with mineral surface area in the upper 2 meters. Immobile element concentrations decrease with increasing depth up to 3 meters, indicating that the preferential removal of mobile elements extends beyond the depth of C-mineral adsorption. Variability of immobile elements in the deep weathering profile reveal variations that could be the result of weathering in fractures but are more likely inherited by the rock composition and particle size of pre-metamorphosed parent rock.

  7. Mexico - Surface Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Mexican Surface Daily Observations taken at 94 observatories located throughout Mexico, beginning in 1872 and going up through 1981. The data resided on paper...

  8. Surface Weather Observations (Pre-1893)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly weather records from U.S. Army Forts stations (~1820-1871), U.S. Army Signal Service Stations (1871-1892), Smithsonian Institution voluntary observer network...

  9. Estimating the impact of wintry weather on transportation in Europe

    Science.gov (United States)

    Juga, I.; Rauhala, J.; Vajda, A.

    2010-09-01

    Wintry weather conditions have high impact on transportation. Sub-zero temperatures combined to snowfall result in traffic jams and increased accident rate. Dense snowfall causes poor grip between the road surface and tires and reduces the visibility, thus increasing the risk for severe pile-ups on highways. Low temperature and snowfall have a strong negative impact also on railway traffic and aviation, as experienced in Europe during winter 2009/10. Many big airfields in Central Europe were closed during several days and thousands of people had to spend the night at the airport or in the hotels nearby. The estimated total costs from a single major snowfall event can climb up to 1.3 billion pounds (1.5 billion euro), as happened in UK on 1-2 February 2009. By investigating the effect of hazardous winter weather conditions on different transport modes the worst situations can be identified and impact thresholds for different weather parameters and their combination can be assessed. In this study we estimate the impact thresholds for snowfall, wind gust and temperature as well as for their combination, the blizzard. This work is based on an impact review collected from literature and media reports as well as on local studies concerning the link between snowfall and traffic accidents for example. From the study on six winters it appears for example that a snowfall of 10 cm/24 h resulted in a double car accident rate on average in southern Finland. Such situations can be regarded as high impact cases (peak days of traffic accidents). It is estimated that climate change and global warming will decrease the average yearly number of wintry days in Europe. Even the northern part will probably have a shorter period of snow cover during the coming decades. However, the variability between different winters will remain and cold air outbreaks with even heavy snowfall can occasionally occur also during mild winters. Several studies have shown that the more uncommon some

  10. Extreme weather impacts on European networks of transport

    Science.gov (United States)

    Leviakangas, P.

    2012-04-01

    The EWENT project addresses the European Union (EU) policies and strategies related to climate change, with a particular focus on extreme weather impacts on the EU transportation system. This project is funded by the Seventh Framework Programme (Transports, call ID FPT7-TPT-2008-RTD-1). EWENT Work Package 1 (WP1) focuses particularly on identification and definition of extreme weather events within the European transport system. In the context of the EWENT project, the following definition for extreme weather events related to transport systems was used: "Extreme events are generally rare events. The events cause the exceeding of maximum values and/or pre-existing (measured) high (low) thresholds of certain weather parameters and generate impacts that are harmful to any part of the transport system (infrastructures, operations, vehicles, passengers or cargo)". Weather has major impacts on transportation. EWENT WP1 used three different approaches to assess the impacts and consequences extreme weather phenomena cause to the transport system. Firstly, an extensive traditional review of the professional literature has been carried out. Secondly, media mining has been done in order to obtain more empirical data and assess which transport modes in different parts of Europe seem to be most affected. Thirdly, a compilation of specific case studies on past extreme incidents has been prepared, helping to assess the specific consequences of certain phenomena. EWENT WP1 introduces a review of extreme weather phenomena and identifies their impacts and consequences on European transport system. All modes of transport are covered. Critical threshold values for most relevant weather phenomena that affect different transport modes have been established. The related impacts and consequences result in deterioration in the service level of transportation system. A dozen different impact mechanisms have been charted. The collaborators in the team for this part of the EWENT Project are

  11. Establishing Sprinkling Requirements on Trailers Transporting Market Weight Pigs in Warm and Hot Weather

    Directory of Open Access Journals (Sweden)

    Rebecca Kephart

    2014-04-01

    Full Text Available This study was conducted July of 2012 in Iowa, in WARM (<26.7 °C and HOT (≥26.7 °C weather. Four sprinkling methods were compared, with one treatment being randomly assigned to each load: control- no sprinkling (not applied in HOT weather, pigs only, bedding only, or pigs and bedding. Experiment 1 used 51 loads in WARM- and 86 loads in HOT weather to determine sprinkling effects on pig measures (surface temperature, vocalizations, slips and falls, and stress signs. Experiment 2 used 82 loads in WARM- and 54 loads in HOT weather to determine the sprinkling effects on transport losses (non-ambulatory, dead, and total transport losses. Experiment 1 found that, in WARM weather, there were no differences between sprinkling treatments for surface temperature, vocalizations, or slips and falls (p ≥ 0.18. However, stress signs were 2% greater when sprinkling pigs- or bedding only- compared to control (p = 0.03. Experiment 2 found that, in WARM and HOT weather, sprinkling did not affect non-ambulatory, dead, or total transport losses (p ≥ 0.18. Although the current study did not find any observed sprinkling effects for pig measures or transport losses it is extremely important to note that the inference space of this study is relatively small, so further studies should be conducted to see if these results are applicable to other geographical regions and seasons.

  12. Cloud information for FIRE from surface weather reports

    Science.gov (United States)

    Hahn, Carole J.; Warren, Stephen G.; London, Julius

    1990-01-01

    Surface weather observations of clouds were analyzed to obtain a global cloud climatology (Warren et al, 1986; 1988). The form of the synoptic weather code limits the types of cloud information which are available from these reports. Comparison of surface weather reports with instrumental observations during the FIRE field experiments can help to clarify the operational definitions which were made in the climatology because of the nature of the synoptic code. The long-term climatology from surface weather observations is also useful background for planning the location and timing of intensive field experiments.

  13. How to assess extreme weather impacts - case European transport network

    Science.gov (United States)

    Leviäkangas, P.

    2010-09-01

    To assess the impacts of climate change and preparing for impacts is a process. This process we must understand and learn to apply. EWENT (Extreme Weather impacts on European Networks of Transport) will be a test bench for one prospective approach. It has the following main components: 1) identifying what is "extreme", 2) assessing the change in the probabilities, 3) constructing the causal impact models, 4) finding appropriate methods of pricing and costing, 5) finding alternative strategy option, 6) assessing the efficiency of strategy option. This process follows actually the steps of standardized risk management process. Each step is challenging, but if EWENT project succeeds to assess the extreme weather impacts on European transport networks, it is one possible benchmark how to carry out similar analyses in other regions and on country level. EWENT approach could particularly useful for weather and climate information service providers, offering tools for transport authorities and financiers to assess weather risks, and then rationally managing the risks. EWENT project is financed by the European Commission and participated by met-service organisations and transport research institutes from different parts of Europe. The presentation will explain EWENT approach in detail and bring forth the findings of the first work packages.

  14. Transport of Aerosols: Regional and Global Implications for Climate, Weather, and Air Quality

    Science.gov (United States)

    Chin, Mian; Diehl, Thomas; Yu, Hongbin; Bian, Huisheng; Remer, Lorraine; Kahn, Ralph

    2008-01-01

    Long-range transport of atmospheric aerosols can have a significant impact on global climate, regional weather, and local air quality. In this study, we use a global model GOCART together with satellite data and ground-based measurements to assess the emission and transport of pollution, dust, biomass burning, and volcanic aerosols and their implications. In particular, we will show the impact of emissions and long-range transport of aerosols from major pollution and dust source regions to (1) the surface air quality, (2) the atmospheric heating rates, and (3) surface radiation change near the source and downwind regions.

  15. Calibrating surface weather observations to atmospheric attenuation measurements

    Science.gov (United States)

    Sanii, Babak

    2001-06-01

    A correlation between near-IR atmospheric attenuation measurements made by the Atmospheric Visibility Monitor (AVM) at the Table Mountain Facility and airport surface weather observations at Edwards Air Force Base has been performed. High correlations (over 0.93) exist between the Edwards observed sky cover and the average AVM measured attenuations over the course of the 10 months analyzed. The statistical relationship between the data-sets allows the determination of coarse attenuation statistics from the surface observations, suggesting that such statistics may be extrapolated from any surface weather observation site. Furthermore, a superior technique for converting AVM images to attenuation values by way of MODTRAN predictions has been demonstrated.

  16. Impacts of extreme weather events on transport infrastructure in Norway

    Science.gov (United States)

    Frauenfelder, Regula; Solheim, Anders; Isaksen, Ketil; Romstad, Bård; Dyrrdal, Anita V.; Ekseth, Kristine H. H.; Gangstø Skaland, Reidun; Harbitz, Alf; Harbitz, Carl B.; Haugen, Jan E.; Hygen, Hans O.; Haakenstad, Hilde; Jaedicke, Christian; Jónsson, Árni; Klæboe, Ronny; Ludvigsen, Johanna; Meyer, Nele K.; Rauken, Trude; Sverdrup-Thygeson, Kjetil

    2016-04-01

    With the latest results on expected future increase in air temperature and precipitation changes reported by the Intergovernmental Panel on Climate Change (IPCC), the climate robustness of important infrastructure is of raising concern in Norway, as well as in the rest of Europe. Economic consequences of natural disasters have increased considerably since 1950. In addition to the effect of demographic changes such as population growth, urbanization and more and more concentration of valuable assets, this increase is also related to an augmenting frequency of extreme events, such as storms, flooding, drought, and landslides. This change is also observable in Norway, where the increased frequency of strong precipitation has led to frequent flooding and landslide events during the last 20 years. A number of studies show that climate change causes an increase in both frequency and intensity of several types of extreme weather, especially when it comes to precipitation. Such extreme weather events greatly affect the transport infrastructure, with numerous and long closures of roads and railroads, in addition to damage and repair costs. Frequent closures of railroad and roads lead to delay or failure in delivery of goods, which again may lead to a loss of customers and/or - eventually - markets. Much of the Norwegian transport infrastructure is more than 50 years old and therefore not adequately dimensioned, even for present climatic conditions. In order to assess these problems and challenges posed to the Norwegian transport infrastructure from present-day and future extreme weather events, the project "Impacts of extreme weather events on infrastructure in Norway (InfraRisk)" was performed under the research Council of Norway program 'NORKLIMA', between 2009 and 2013. The main results of the project are: - Moderate to strong precipitation events have become more frequent and more intense in Norway over the last 50 years, and this trend continues throughout the 21st

  17. Jovian magnetospheric weathering of Europa's nonice surface material

    Science.gov (United States)

    Hibbitts, Charles A.; Paranicas, Christopher; Blaney, Diana L.; Murchie, Scott; Seelos, Frank

    2016-10-01

    Jovian plasma and energetic charged particles bombard the Galilean satellites. These satellites vary from volcanically active (Io) to a nearly primordial surface (Callisto). These satellites are imbedded in a harsh and complex particle radiation environment that weathers their surfaces, and thus are virtual laboratories for understanding how particle bombardment alters the surfaces of airless bodies. Europa orbits deeply in the Jovian radiation belts and may have an active surface, where space weathering and geologic processes can interact in complex ways with a range of timescales. At Europa's surface temperature of 80K to 130K, the hydrated nonice material and to a lesser extent, water ice, will be thermally stable over geologic times and will exhibit the effects of weathering. The ice on the surface of Europa is amorphous and contains trace products such as H2O2 [1] due to weathering. The nonice material, which likely has an endogenic component [2] may also be partially amorphous and chemically altered as a result of being weathered by electrons, Iogenic sulfur, or other agents [3]. This hydrated salt or frozen brine likely compositionally 'matures' over time as the more weakly bound constituents are preferentially removed compared with Ca and Mg [4]. Electron bombardment induces chemical reactions through deposition of energy (e.g., ionizations) possibly explaining some of the nonice material's redness [5,6]. Concurrently, micrometeroid gardening mixes the upper surface burying weathered and altered material while exposing both fresh material and previous altered material, potentially with astrobiological implications. Our investigation of the spectral alteration of nonice analog materials irradiated by 10s keV electrons demonstrates the prevalence of this alteration and we discuss relevance to potential measurements by the Europa MISE instrument.References: [1] Moore, M. and R. Hudson, (2000), Icarus, 145, 282-288; [2] McCord et al., (1998), Science, 280, 1242

  18. Weather, transport mode choices and emotional travel experiences

    NARCIS (Netherlands)

    Böcker, L.; Dijst, M.J.; Faber, J.

    2016-01-01

    With climate change high on the political agenda, weather has emerged as an important issue in travel behavioral research and urban planning. While various studies demonstrate profound effects of weather on travel behaviors, limited attention has been paid to subjective weather experiences and the

  19. The impact of synoptic weather on UK surface ozone and implications for premature mortality

    Science.gov (United States)

    Pope, R. J.; Butt, E. W.; Chipperfield, M. P.; Doherty, R. M.; Fenech, S.; Schmidt, A.; Arnold, S. R.; Savage, N. H.

    2016-12-01

    Air pollutants, such as ozone, have adverse impacts on human health and cause, for example, respiratory and cardiovascular problems. In the United Kingdom (UK), peak surface ozone concentrations typically occur in the spring and summer and are controlled by emission of precursor gases, tropospheric chemistry and local meteorology which can be influenced by large-scale synoptic weather regimes. In this study we composite surface and satellite observations of summer-time (April to September) ozone under different UK atmospheric circulation patterns, as defined by the Lamb weather types. Anticyclonic conditions and easterly flows are shown to significantly enhance ozone concentrations over the UK relative to summer-time average values. Anticyclonic stability and light winds aid the trapping of ozone and its precursor gases near the surface. Easterly flows (NE, E, SE) transport ozone and precursor gases from polluted regions in continental Europe (e.g. the Benelux region) to the UK. Cyclonic conditions and westerly flows, associated with unstable weather, transport ozone from the UK mainland, replacing it with clean maritime (North Atlantic) air masses. Increased cloud cover also likely decrease ozone production rates. We show that the UK Met Office regional air quality model successfully reproduces UK summer-time ozone concentrations and ozone enhancements under anticyclonic and south-easterly conditions for the summer of 2006. By using established ozone exposure-health burden metrics, anticyclonic and easterly condition enhanced surface ozone concentrations pose the greatest public health risk.

  20. Space Weathering of the Lunar Surface by Solar Wind Particles

    Science.gov (United States)

    Kim, Sungsoo S.; Sim, Chaekyung

    2017-08-01

    The lunar regolith is space-weathered to a different degree in response to the different fluxes of incident solar wind particles and micrometeoroids. Crater walls, among other slating surfaces, are good tracers of the space-weathering process because they mature differently depending on the varying incident angles of weathering agents. We divide a crater wall into four quadrants (north, south, east, and west) and analyze the distribution of 950-nm/750-nm reflectance-ratio and 750-nm reflectance values in each wall quadrant, using the topography-corrected images by Multispectral Imager (MI) onboard SELENE (Kaguya). For thousands of impact craters across the Moon, we interpret the spectral distributions in the four wall quadrants in terms of the space weathering by solar wind particles and micrometeoroids and of gardening by meteroids. We take into account the solar-wind shielding by the Earth’s magnetotail to correctly assess the different spectral behaviors between east- and west-facing walls of the craters in the near-side of the Moon.

  1. Verification of Forecast Weather Surface Variables over Vietnam Using the National Numerical Weather Prediction System

    Directory of Open Access Journals (Sweden)

    Tien Du Duc

    2016-01-01

    Full Text Available The national numerical weather prediction system of Vietnam is presented and evaluated. The system is based on three main models, namely, the Japanese Global Spectral Model, the US Global Forecast System, and the US Weather Research and Forecasting (WRF model. The global forecast products have been received at 0.25- and 0.5-degree horizontal resolution, respectively, and the WRF model has been run locally with 16 km horizontal resolution at the National Center for Hydro-Meteorological Forecasting using lateral conditions from GSM and GFS. The model performance is evaluated by comparing model output against observations of precipitation, wind speed, and temperature at 168 weather stations, with daily data from 2010 to 2014. In general, the global models provide more accurate forecasts than the regional models, probably due to the low horizontal resolution in the regional model. Also, the model performance is poorer for stations with altitudes greater than 500 meters above sea level (masl. For tropical cyclone performance validations, the maximum wind surface forecast from global and regional models is also verified against the best track of Joint Typhoon Warning Center. Finally, the model forecast skill during a recent extreme rain event in northeast Vietnam is evaluated.

  2. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    Directory of Open Access Journals (Sweden)

    Lei Li

    2014-10-01

    Full Text Available The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management.

  3. A weather type method to study surface ocean variables

    Science.gov (United States)

    Menendez, M.; Camus, P.; Mendez, F. J.; Losada, I. J.

    2012-04-01

    The set of methodologies for obtaining wave climate information at high spatial resolution from relatively coarse resolution is known as downscaling. Dynamic downscaling, based on the use of numerical models, is perhaps the most widely used methodology for surface ocean variables. An alternative approach is the statistical downscaling, that can be conducted by means of regression methods or weather pattern-based approaches. The main advantages of the statistical downscaling based on weather patterns are: the low computational requirements; the ease of implementation; the additional climatology information; and local forecast application. Moreover, this technique allows exploring the synoptic atmospheric climatology and their relationship with surface ocean variables. It is well known nowadays that the seasonal-to-interannual variability of wave climate is linked to the atmosphere circulation patterns. We proposed a statistical approach based on the predictand (eg. local wave characteristics) is associated to a particular synoptic-scale weather type (predictor). The predictor is the n-days-averaged sea level pressure field (SLP) anomalies, which are synthesized using data mining techniques to describe a number of weather types. In particular, we focus in NE Atlantic (NAO region) using as predictor the 3-days-averaged SLP fields calculated by NCEP atmospheric reanalysis (1948-2010). A principal component analysis is applied over SLP fields to reduce the spatial and temporal dimensions. The K-means clustering technique is then applied to the two-dimensional sample of the principal components which explain more than 95% variance of the SLP. The K-means technique divides the data space into a number of clusters, where each of them is characterized by a centroid and formed by the data for which the centroid is the nearest. Finally, we visualize the weather types associated to each centroid in an ordered way similar to self-organizing maps, SOMs. The probability

  4. Evidence of Space Weathering Processes Across the Surface of Vesta

    Science.gov (United States)

    Pieters, Carle M.; Blewett, David T.; Gaffey, Michael; Mittlefehldt, David W.; CristinaDeSanctis, Maria; Reddy, Vishnu; Coradini, Angioletta; Nathues, Andreas; Denevi, Brett W.; Li, Jian-Yang; hide

    2011-01-01

    As NASA s Dawn spacecraft explores the surface of Vesta, it has become abundantly clear that Vesta is like no other planetary body visited to date. Dawn is collecting global data at increasingly higher spatial resolution during its one-year orbital mission. The bulk properties of Vesta have previously been linked to the HED meteorites through remote mineral characterization of its surface from Earth-based spectroscopy. A principal puzzle has been why Vesta exhibits relatively unweathered diagnostic optical features compared to other large asteroids. Is this due to the composition of this proto-planet or the space environment at Vesta? Alteration or weathering of materials in space normally develops as the products of several processes accumulate on the surface or in an evolving particulate regolith, transforming the bedrock into fragmental material with properties that may be measurably different from the original. Data from Dawn reveal that the regolith of Vesta is exceptionally diverse. Regional surface units are observed that have not been erased by weathering with time. Several morphologically-fresh craters have excavated bright, mafic-rich materials and exhibit bright ray systems. Some of the larger craters have surrounding subdued regions (often asymmetric) that are lower in albedo and relatively red-sloped in the visible while exhibiting weaker mafic signatures. Several other prominent craters have rim exposures containing very dark material and/or display a system of prominent dark rays. Most, but not all, dark areas associated with craters exhibit significantly lower spectral contrast, suggesting that either a Vesta lithology with an opaque component has been exposed locally or that the surface has been contaminated by a relatively dark impactor. Similarly, most, but not all, bright areas associated with craters exhibit enhanced mafic signatures compared to surroundings. On a regional scale, the large south polar structure and surrounding terrain exhibit

  5. A comparison of all-weather land surface temperature products

    Science.gov (United States)

    Martins, Joao; Trigo, Isabel F.; Ghilain, Nicolas; Goettche, Frank-M.; Ermida, Sofia; Olesen, Folke-S.; Gellens-Meulenberghs, Françoise; Arboleda, Alirio

    2017-04-01

    The Satellite Application Facility on Land Surface Analysis (LSA-SAF, http://landsaf.ipma.pt) has been providing land surface temperature (LST) estimates using SEVIRI/MSG on an operational basis since 2006. The LSA-SAF service has since been extended to provide a wide range of satellite-based quantities over land surfaces, such as emissivity, albedo, radiative fluxes, vegetation state, evapotranspiration, and fire-related variables. Being based on infra-red measurements, the SEVIRI/MSG LST product is limited to clear-sky pixels only. Several all-weather LST products have been proposed by the scientific community either based on microwave observations or using Soil-Vegetation-Atmosphere Transfer models to fill the gaps caused by clouds. The goal of this work is to provide a nearly gap-free operational all-weather LST product and compare these approaches. In order to estimate evapotranspiration and turbulent energy fluxes, the LSA-SAF solves the surface energy budget for each SEVIRI pixel, taking into account the physical and physiological processes occurring in vegetation canopies. This task is accomplished with an adapted SVAT model, which adopts some formulations and parameters of the Tiled ECMWF Scheme for Surface Exchanges over Land (TESSEL) model operated at the European Center for Medium-range Weather Forecasts (ECMWF), and using: 1) radiative inputs also derived by LSA-SAF, which includes surface albedo, down-welling fluxes and fire radiative power; 2) a land-surface characterization obtained by combining the ECOCLIMAP database with both LSA-SAF vegetation products and the H(ydrology)-SAF snow mask; 3) meteorological fields from ECMWF forecasts interpolated to SEVIRI pixels, and 4) soil moisture derived by the H-SAF and LST from LSA-SAF. A byproduct of the SVAT model is surface skin temperature, which is needed to close the surface energy balance. The model skin temperature corresponds to the radiative temperature of the interface between soil and atmosphere

  6. nowCOAST's Map Service for Surface Weather and Ocean Observations (Time Enabled)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Map Information: This nowCOAST time-enabled map service provides maps depicting the latest surface weather and marine weather observations at observing sites using...

  7. A Study of Aerosols Transportation around City Boundary in the Fog Weather

    Science.gov (United States)

    Ding, J.; Li, J. H.; Liu, Y.; Zhang, B. L.; Wang, Q. T.

    2011-09-01

    The structure of city surface seriously affects transport and diffusion of pollutant aerosol particles in the fog weather. So dynamic model population balance model (PBM) of aerosol particles and multiphase-coupled flow model were established to describe the fluid-particle system of fog. Based on the Eulerian-Lagrangian method and Multi-Monte Carlo method, a study of aerosols transportation around city boundary was conducted. The computed results show a part of aerosols change into droplets during the formation of fog, and the average sizes of aerosols, droplets are about 0.032 7 μm and 28.7 μm with time evolution to 60 min. For the development of fog, with time of 60 min and wind of 2 m/s, the number of aerosol is down to 84.5% of initial value, and the average particle size is down to 22.1 μm accordingly. During the dissipation of fog, the numbers of aerosol and fog droplet are decreased to the 1.65% and 0.016 5% of initial value. As wind speed rising, the turbulent motion strength of particles is increased. Eventually, the droplets have almost disappeared, and a small number of aerosols are still suspended in the atmosphere. The computed results reflect the transport and dynamic characteristics for respirable aerosols around city boundary during three stages of fog.

  8. Formation of the Surface Space Charge Layer in Fair Weather

    Science.gov (United States)

    Redin, Alexander; Kupovykh, Gennady; Boldyreff, Anton

    2014-05-01

    It is widely known that the positive space charge, caused by electrode effect action, is obtained near surface in fair weather. Space charge density depends on the different local features: meteorological conditions, aerosol particles concentration, convective transfer of the surface layer. Namely space charge determines the local variations of electric field. Space charge could be negative in condition of strong ionization rate in thin air layer near surface. The electrodynamic model, consisting of transfer equations of light ions and nucleuses, generated by interactions between lights ions and aerosol particles, and Poisson equation. The turbulent transfer members, electric field near the surface, the mobility of positive and negative ions, recombination coefficient, ionization rate, the number of elementary charges on the nuclei were took into account in the model equations. The time-space variations of positive and negative small and heavy ions, electric field, electrical conductivity, current density and space charge, depending on aerosol particles concentrations, turbulence and convective transfer ionization rate, aerosol particles size and number of charged on the particles are calculated. The mechanisms of turbulent and convection-turbulent surface layer electrodynamic structure forming in dependence of single and multi-charged aerosol particles for different physical and meteorological conditions are investigated. Increasing of turbulent mixing intensity leads to increasing of character electrode layer thickness, decreasing of space charge density value, decreasing of electric current conductivity value. The electrode effect of the whole layer remains constant. Increasing of aerosol particles concentration leads to decreasing of electrode effect within the whole electrode layer and increasing of electric field values, decreasing of space charge density values and current conductivity density. It was received that increasing of the aerosol particles

  9. Composition, origin and weathering process of surface sediment in Kumtagh Desert, Northwest China

    Institute of Scientific and Technical Information of China (English)

    XU Zhiwei; LU Huayu; ZHAO Cunfa; WANG Xianyan; SU Zhizhua; WANG Zhenting; LIU Hongyi; WANG Lixin; LU Qi

    2011-01-01

    Kumtagh Desert is one of the eight biggest deserts in China,but poorly investigated before our interdisciplinary study because of the difficulty of access.In this paper,33 representative surface sediment samples were collected from the Kumtagh Desert and analyzed in the laboratory to obtain heavy mineral components and geochemical element contents.Results show that various kinds of heavy minerals are present in these samples,with high levels of epidote and hornblende.Si and AI take up a large part of chemical composition.Compared with the average composition of geochemical elements of the upper continental crust (UCC),except Si and Ca,all elements are depleted to a certain degree; Fe,Mg,Ca,P,Ti and Mn have high correlation coefficients in their contents.The mineral and geochemical composition of the Kumtagh Desert sediments have a similarity with that of rocks of Altyn Tagh Mountains,and the surface sediments of the alluvial/diluvial fans around the Altyn Tagh Mountains and that of the Taklamakan Desert,indicating that one major source of the Kumtagh Desert sediments is located in the Altyn Tagh Mountains.Alluvial deposits and lake sediments in Aqik valley and lower reaches of Shule River are prone to be eroded and transported by the strong northeasterly wind into the Kumtagh Desert,forming another source of the desert deposits.An A-CN-K ternary diagram shows that a weak degree chemical weathering by the loss of Na and K occurred in these sediments,whereas A-CNK-FM temary diagram suggests that Fe and Mg have undergone a significant chemical differentiation.Physical weathering processes cause easy erosion and enrichment in fine particles for mafic minerals,thus coarse desert sand particles can be relatively depleted in Fe and Mg.The mineral and geochemical composition of sediments in arid regions experiencing less chemical weathering are mostly affected by physical weathering.

  10. Investigating the influence of subsurface heterogeneity on chemical weathering in the critical zone using high resolution reactive transport models

    Science.gov (United States)

    Pandey, S.; Rajaram, H.

    2014-12-01

    The critical zone (CZ) represents a major life-sustaining realm of the terrestrial surface. The processes controlling the development and transformation of the CZ are important to continued health of the planet as human influence continues to grow. The CZ encompasses the shallow subsurface, a region of reaction, unsaturated flow, and transport. Chemical weathering in the subsurface is one of the important processes involved in the formation and functioning of the CZ. We present two case studies of reactive transport modeling to investigate the influence of subsurface heterogeneity and unsaturated flow on chemical weathering processes in the CZ. The model is implemented using the reactive transport code PFLOTRAN. Heterogeneity in subsurface flow is represented using multiple realizations of conductive fracture networks in a hillslope cross-section. The first case study is motivated by observations at the Boulder Creek Critical Zone Observatory (BCCZO) including extensive hydrologic and geochemical datasets. The simulations show that fractures greatly enhance weathering as compared to a homogeneous porous medium. Simulations of north-facing slope hydrology with prolonged snowmelt pulses also increases weathering rates, showing the importance of slope aspect on weathering intensity. Recent work elucidates deteriorating water quality caused by climate change in the CZ of watersheds where acid rock drainage (ARD) occurs. The more complex reactions of ARD require a customized kinetic reaction module with PFLOTRAN. The second case study explores the mechanisms by which changes in hydrologic forcing, air and ground temperatures, and water table elevations influence ARD. For instance, unreacted pyrite exposed by a water table drop was shown to produce a 125% increase in annual pyrite oxidization rate, which provides one explanation for increased ARD.

  11. Weather Station and Sensor Locations, MDTA Roadway weather station, weather stations, weather sensors, Roadway weather sensors, RWIS, MDTA weather sensors, Published in 2009, 1:1200 (1in=100ft) scale, Maryland Transportation Authority.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Weather Station and Sensor Locations dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Hardcopy Maps information as of 2009. It...

  12. Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroid Space Weathering Studies

    Science.gov (United States)

    Dominque, Deborah L.; Chapman, Clark R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Orlando, Thomas M.; Schriver, David; hide

    2011-01-01

    Understanding the composition of Mercury's crust is key to comprehending the formation of the planet. The regolith, derived from the crustal bedrock, has been altered via a set of space weathering processes. These processes are the same set of mechanisms that work to form Mercury's exosphere, and are moderated by the local space environment and the presence of an intrinsic planetary magnetic field. The alterations need to be understood in order to determine the initial crustal compositions. The complex interrelationships between Mercury's exospheric processes, the space environment, and surface composition are examined and reviewed. The processes are examined in the context of our understanding of these same processes on the lunar and asteroid regoliths. Keywords: Mercury (planet) Space weathering Surface processes Exosphere Surface composition Space environment 3

  13. Physical and chemical weathering. [of Martian surface and rocks

    Science.gov (United States)

    Gooding, James L.; Arvidson, Raymond E.; Zolotov, Mikhail IU.

    1992-01-01

    Physical and chemical weathering processes that might be important on Mars are reviewed, and the limited observations, including relevant Viking results and laboratory simulations, are summarized. Physical weathering may have included rock splitting through growth of ice, salt or secondary silicate crystals in voids. Chemical weathering probably involved reactions of minerals with water, oxygen, and carbon dioxide, although predicted products vary sensitively with the abundance and physical form postulated for the water. On the basis of kinetics data for hydration of rock glass on earth, the fate of weathering-rind formation on glass-bearing Martian volcanic rocks is tentatively estimated to have been on the order of 0.1 to 4.5 cm/Gyr; lower rates would be expected for crystalline rocks.

  14. Indication of insensitivity of planetary weathering behavior and habitable zone to surface land fraction

    CERN Document Server

    Abbot, Dorian S; Ciesla, Fred J

    2012-01-01

    It is likely that unambiguous habitable zone terrestrial planets of unknown water content will soon be discovered. Water content helps determine surface land fraction, which influences planetary weathering behavior. This is important because the silicate weathering feedback determines the width of the habitable zone in space and time. Here a low-order model of weathering and climate, useful for gaining qualitative understanding, is developed to examine climate evolution for planets of various land-ocean fractions. It is pointed out that, if seafloor weathering does not depend directly on surface temperature, there can be no weathering-climate feedback on a waterworld. This would dramatically narrow the habitable zone of a waterworld. Results from our model indicate that weathering behavior does not depend strongly on land fraction for partially ocean-covered planets. This is powerful because it suggests that previous habitable zone theory is robust to changes in land fraction, as long as there is some land. F...

  15. Widespread Weathered Glass on the Surface of Mars

    Science.gov (United States)

    Horgan, Briony; Bell, James F., III

    2012-01-01

    Low albedo sediments cover >10(exp 7) sq km in the northern lowlands of Mars, but the composition and origin of these widespread deposits have remained ambiguous despite many previous investigations. Here we use near-infrared spectra acquired by the Mars Express OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite') imaging spectrometer to show that these sediments exhibit spectral characteristics that are consistent with both high abundances of iron-bearing glass and silica-enriched leached rinds on glass. This interpretation is supported by observations of low-albedo soil grains with possible rinds at the Phoenix Mars Lander landing site in the northern lowlands. By comparison with the extensive glass-rich dune fields and sand sheets of Iceland, we propose an explosive volcanic origin for these glass-rich sediments. We also propose that the glassy remnant rinds on the sediments are the result of post-depositional alteration, as these rinds are commonly formed in arid terrestrial volcanic environments during water-limited, moderately acidic leaching. These weathered, glass-rich deposits in the northern lowlands are also colocated with the strongest concentrations of a major global compositional surface type previously identified in mid-infrared spectra, suggesting that they may be representative of global processes. Our results provide potential confirmation of models suggesting that explosive volcanism has been widespread on Mars, and also raise the possibilities that glass-rich volcaniclastics are a major source of eolian sand on Mars and that widespread surficial aqueous alteration has occurred under Amazonian climatic conditions.

  16. Driver behaviour data linked with vehicle, weather, road surface, and daylight data.

    Science.gov (United States)

    Hjelkrem, Odd André; Ryeng, Eirin Olaussen

    2017-02-01

    In this data set, vehicle observations have been linked to data containing weather and road surface conditions. A total of 311 908 observations are collected and classified in categories of precipitation type, road status information, and daylight condition. The data is collected for a long period of time, so that several different weather situations are present, ranging from dry summer to adverse winter weather conditions.

  17. Surface Exposure Ages of Space-Weathered Grains from Asteroid 25143 Itokawa

    Science.gov (United States)

    Keller, L. P.; Berger, E. L.; Christoffersen, R.

    2015-01-01

    Space weathering processes such as solar wind ion irradiation and micrometeorite impacts are widely known to alter the properties of regolith materials exposed on airless bodies. The rates of space weathering processes however, are poorly constrained for asteroid regoliths, with recent estimates ranging over many orders of magnitude. The return of surface samples by JAXA's Hayabusa mission to asteroid 25143 Itokawa, and their laboratory analysis provides "ground truth" to anchor the timescales for space weathering processes on airless bodies.

  18. Atmospheric Visual and Infrared Transmission Deduced from Surface Weather Observations: Weather and Warplanes. V1

    Science.gov (United States)

    1976-10-01

    require stadistically valid predictions of PGM utility as a function of weather conditions in different potential theaters of combat at different times of...resource in making statisti- cally valid predictions of weapon performance (including diurnal, sea- sonal, and geographic variability). The model of...dewpoint range IO°F- 700F. -1 -16- be valid at 296 0K (73*F). They further suggest a strong temperature dependence of yc. (These corrections have been

  19. Weather Radar Adjustment Using Runoff from Urban Surfaces

    DEFF Research Database (Denmark)

    Ahm, Malte; Rasmussen, Michael Robdrup

    2017-01-01

    Weather radar data used for urban drainage applications are traditionally adjusted to point ground references, e.g., rain gauges. However, the available rain gauge density for the adjustment is often low, which may lead to significant representativeness errors. Yet, in many urban catchments......, rainfall is often measured indirectly through runoff sensors. This paper presents a method for weather radar adjustment on the basis of runoff observations (Z-Q adjustment) as an alternative to the traditional Z-R adjustment on the basis of rain gauges. Data from a new monitoring station in Aalborg......, Denmark, were used to evaluate the flow-based weather radar adjustment method against the traditional rain-gauge adjustment. The evaluation was performed by comparing radar-modeled runoff to observed runoff. The methodology was both tested on an events basis and multiple events combined. The results...

  20. 2007 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.

    2009-01-01

    Weather data constitute an integral part of ecosystem monitoring in the Colorado River corridor and are particularly valuable for understanding processes of landscape change that contribute to the stability of archeological sites. Data collected in 2007 are reported from nine weather stations in the Colorado River corridor through Grand Canyon, Ariz. The stations were deployed in February and March 2007 to measure wind speed and direction, rainfall, air temperature, relative humidity, and barometric pressure. Sand traps near each weather station collect windblown sand, from which daily aeolian sand-transport rates are calculated. The data reported here were collected as part of an ongoing study to test and evaluate methods for quantifying processes that affect the physical integrity of archeological sites along the river corridor; as such, these data can be used to identify rainfall events capable of causing gully incision and to predict likely transport pathways for aeolian sand, two landscape processes integral to the preservation of archeological sites. Weather data also have widespread applications to other studies of physical, cultural, and biological resources in Grand Canyon. Aeolian sand-transport data reported here, collected in the year before the March 2008 High-Flow Experiment (HFE) at Glen Canyon Dam, represent baseline data against which the effects of the 2008 HFE on windblown sand will be compared in future reports.

  1. Surface transport in plasma-balls

    CERN Document Server

    Armas, Jay; Kundu, Nilay

    2015-01-01

    We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an applic...

  2. Vacancy Transport and Interactions on Metal Surfaces

    Science.gov (United States)

    2014-03-06

    AFRL-OSR-VA-TR-2013-0317 VACANCY TRANSPORT AND INTERACTIONS ON METAL SURFACES Gert Ehrlich UNIVERSITY OF ILLINOIS CHAMPAIGN Final Report 03/06/2014...30, 2012 Gert Ehrlich , PI Abstract This proposal is a study of vacancy transport and vacancy interaction on metal surfaces. Adatom self...Trembułowicz, Gert Ehrlich , Grażyna Antczak,Surface diffusion of gold on quasihexagonal-reconstructed Au(100) ,Physical Review B 84 (2011) 245445-1

  3. Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; O’Day, Peggy; Rivera, Nelson; Um, Wooyong; Chang, Hyun-Shik; Steefel, Carl; Thompson, Aaron

    2012-11-05

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

  4. Release of Aged Contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Chorover, Jon [Univ. of Arizona, Tucson, AZ (United States); Perdrial, Nico [Univ. of Arizona, Tucson, AZ (United States); Mueller, Karl [Pennsylvania State Univ., University Park, PA (United States); Strepka, Caleb [Pennsylvania State Univ., University Park, PA (United States); O' Day, Peggy [Univ. of California, Merced, CA (United States); Rivera, Nelson [Univ. of California, Merced, CA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chang, Hyun-Shik [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Steefel, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thompson, Aaron [Univ. of Georgia, Athens, GA (United States)

    2012-08-14

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake (Chorover et al., 2008). In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. Below, we provide some detailed descriptions of our results from this three year study, recently completed following a one-year no cost extension.

  5. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xianai [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Duygu, E-mail: dkocaefe@uqac.ca [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Yasar [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Boluk, Yaman [University of Alberta, 3-142 Markin/CNRL Natural Resources Engineering Facility, Edmonton, Alberta, T6G 2W2 (Canada); Krause, Cornelia [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Investigate detailed structural changes of heat-treated wood due to weathering. Black-Right-Pointing-Pointer Identify connection between physical structural changes and chemical degradation. Black-Right-Pointing-Pointer Study effect of heat treatment conditions on weathering degradation process. - Abstract: Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  6. Chemical weathering rates in deep-sea sediments: Comparison of multicomponent reactive transport models and estimates based on 234U

    Science.gov (United States)

    Maher, K.; Steefel, C. I.; Depaolo, D. J.

    2004-12-01

    Chemical weathering rates in natural systems are typically much slower than expected based on experiments and theory. There are several possible explanations. However, because it has been difficult to determine what effects in particular reduce the rates in specific settings, natural rates remain difficult to predict. Silicate-rich deep-sea sediments provide an ideal in-situ laboratory for investigating weathering rates because certain potentially important factors, such as advective transport through heterogeneous media, limitations on the availability of reactive surface area due to low porosity and/or cementation, unsaturated flow conditions, and seasonal variations in fluid flux and temperature, do not occur in this setting. Geochemical profiles from Site 984 in the North Atlantic are modeled using a multi-component reactive transport model (CRUNCH) to determine in-situ rates of plagioclase dissolution and other diagenetic processes, including sulfate reduction and anaerobic methane oxidation. Various possible processes which might contribute to slower rates in the field are considered, including the effect of mineral saturation state, secondary precipitation of clays, inhibition by dissolved aluminum, and the availability of reactive surface area. The reactive transport model includes an isotopic solid-solution formulation that tracks the isotopic composition of precipitating (calcite) and dissolving (plagioclase and calcite) phases, thus allowing the determination of plagioclase dissolution rates. The rate constants for plagioclase determined by geochemical transport modeling of major element profiles are within the same range determined from U-series calculations and suggest that natural weathering rates for this system are on the order of 10-17.5 to 10-17.7 mol/m2/sec assuming estimates of reactive surface area are correct, several orders of magnitude slower than laboratory-derived rates. The slow plagioclase rates are most likely due to the fact that

  7. Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies

    Science.gov (United States)

    Domingue, Deborah L.; Chapman, Clark. R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Schriver, David; Travnicek, Pavel M.; Orlando, Thomas M.; Sprague, Ann L.; Blewett, David T.; Gillis-Davis, Jeffrey J.; Feldman, William C.; Lawrence, David J.; Ho, George C.; Ebel, Denton S.; Nittler, Larry R.; Vilas, Faith; Pieters, Carle M.; Solomon, Sean C.; Johnson, Catherine L.; Winslow, Reka M..; Helbert, Jorn; Peplowski, Patrick N.; Weider, Shoshana Z.; Mouawad, Nelly; Izenberg, Noam R.; McClintock, William E.

    2014-01-01

    Mercury's regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret crustal composition, it is necessary to understand the nature of these surface alterations. The processes that space weather the surface are the same as those that form Mercury's exosphere (micrometeoroid flux and solar wind interactions) and are moderated by the local space environment and the presence of a global magnetic field. To comprehend how space weathering acts on Mercury's regolith, an understanding is needed of how contributing processes act as an interactive system. As no direct information (e.g., from returned samples) is available about how the system of space weathering affects Mercury's regolith, we use as a basis for comparison the current understanding of these same processes on lunar and asteroidal regoliths as well as laboratory simulations. These comparisons suggest that Mercury's regolith is overturned more frequently (though the characteristic surface time for a grain is unknown even relative to the lunar case), more than an order of magnitude more melt and vapor per unit time and unit area is produced by impact processes than on the Moon (creating a higher glass content via grain coatings and agglutinates), the degree of surface irradiation is comparable to or greater than that on the Moon, and photon irradiation is up to an order of magnitude greater (creating amorphous grain rims, chemically reducing the upper layers of grains to produce nanometer scale particles of metallic iron, and depleting surface grains in volatile elements and alkali metals). The processes that chemically reduce the surface and produce nanometer-scale particles on Mercury are suggested to be more effective than similar processes on the Moon. Estimated abundances of nanometer-scale particles can account for Mercury's dark surface relative to that of the Moon without requiring macroscopic grains of opaque minerals. The presence of

  8. Wurtsmith AFB, Michigan. Revised Uniform Summary of Surface Weather Observations. Parts A-F.

    Science.gov (United States)

    1987-06-12

    USAFETACITN-63-0I. "AN AID FOR USING THE REVISED UNIFORM SUMMARY OF SURFACE WEATHER OBSERVATIONS" 1RUSSAO. TABLE OF CONTENTS STATION HISTORY C PART A: WEATHER...24 634 OSC STATION LOCATION AND INSTRUMENTATION HISTORY Vitt~f tLAU UELtlNE L~TI EMI AIM WK A.1. U 6itffn maI~t . 041 1 Oscoda AA ich A Jul.43 1 Aug43...fla saiTT[I SUSHI ~ 15658 __________________ 1 Jul 43 1/A N/A 1/A N/A 2 JU 53 Permanently mounted on iop of AN/GMQ-1 ML-204-~1 30 ft the weather

  9. Soesterberg, Netherlands. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    Science.gov (United States)

    1978-07-13

    3 6.3 WSW CA1LM02 1. 1.6 A TOA NUBE O3 O1ERATON 213 .65’ I WN(I18 0 3s e. - -N - SFEA DO 08. (O.A PS 1OJ 1DTOSO*TI7OMMEODLT NNW~ a -? 3 � s VARIL...9051 + +j’+, 34 4 40 7 t1 .2 22+*821 82,61+-+ + a!+ of + TOTAL NUBE OF OBEVAIN 683 + 64:P: .. :++: .5:. .(O. A).. . +++.+.,+s f ms o n 1001 USAF...ON 9 981&1S Oi AM oWo - -- - -- -- ’ -ൈ 2 -- TOTAL NUBE OF~d OSRAIN 25 pp f, k- DATA PRUC SSINGBRANCHCCEILING VERSUS VISIBILITY AIR WEATHER SERVICE

  10. Surface Reactivity in Tropical Highly Weathered Soils and Implications for Rational Soil Management

    Institute of Scientific and Technical Information of China (English)

    R. MOREAU; J. PETARD

    2004-01-01

    Highly weathered soils are distributed in the humid and wet-dry tropics, as well as in the humid subtropics. As a result of strong weathering, these soils are characterized by low activity clays, which develop variable surface charge and related specific properties. Surface reactions regarding base exchange and soil acidification, heavy metal sorption and mobility, and phosphorus sorption and availability of the tropical highly weathered soils are reviewed in this paper.Factors controlling surface reactivity towards cations and anions, including ion exchange and specific adsorption processes, are discussed with consideration on practical implications for rational management of these soils. Organic matter content and pH value are major basic factors that should be controlled through appropriate agricultural practices, in order to optimise favorable effects of colloid surface properties on soil fertility and environmental quality.

  11. On the dual nature of lichen-induced rock surface weathering in contrasting micro-environments.

    Science.gov (United States)

    Marques, Joana; Gonçalves, João; Oliveira, Cláudia; Favero-Longo, Sergio E; Paz-Bermúdez, Graciela; Almeida, Rubim; Prieto, Beatriz

    2016-10-01

    Contradictory evidence from biogeomorphological studies has increased the debate on the extent of lichen contribution to differential rock surface weathering in both natural and cultural settings. This study, undertaken in Côa Valley Archaeological Park, aimed at evaluating the effect of rock surface orientation on the weathering ability of dominant lichens. Hyphal penetration and oxalate formation at the lichen-rock interface were evaluated as proxies of physical and chemical weathering, respectively. A new protocol of pixel-based supervised image classification for the analysis of periodic acid-Schiff stained cross-sections of colonized schist revealed that hyphal spread of individual species was not influenced by surface orientation. However, hyphal spread was significantly higher in species dominant on northwest facing surfaces. An apparently opposite effect was noticed in terms of calcium oxalate accumulation at the lichen-rock interface; it was detected by Raman spectroscopy and complementary X-ray microdiffraction on southeast facing surfaces only. These results suggest that lichen-induced physical weathering may be most severe on northwest facing surfaces by means of an indirect effect of surface orientation on species abundance, and thus dependent on the species, whereas lichen-induced chemical weathering is apparently higher on southeast facing surfaces and dependent on micro-environmental conditions, giving only weak support to the hypothesis that lichens are responsible for the currently observed pattern of rock-art distribution in Côa Valley. Assumptions about the drivers of open-air rock-art distribution patterns elsewhere should also consider the micro-environmental controls of lichen-induced weathering, to avoid biased measures of lichen contribution to rock-art deterioration.

  12. Surface transport in plasma-balls

    Energy Technology Data Exchange (ETDEWEB)

    Armas, Jay [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Bhattacharya, Jyotirmoy [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Kundu, Nilay [Harish-Chandra Research Institute,Chhatnag Road, Jhunsi, Allahabad 211019 (India)

    2016-06-06

    We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an application, we study the effect of temperature dependence of surface tension on some explicit examples of localized fluid configurations, which are dual to certain non-trivial black hole solutions via the AdS/CFT correspondence.

  13. Surface transport in plasma-balls

    Science.gov (United States)

    Armas, Jay; Bhattacharya, Jyotirmoy; Kundu, Nilay

    2016-06-01

    We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an application, we study the effect of temperature dependence of surface tension on some explicit examples of localized fluid configurations, which are dual to certain non-trivial black hole solutions via the AdS/CFT correspondence.

  14. Ground effects of space weather investigated by the surface impedance

    Science.gov (United States)

    Pirjola, R.; Boteler, D.; Trichtchenko, L.

    2009-02-01

    The objective of this paper is to provide a discussion of the surface impedance applicable in connection with studies of geomagnetically induced currents (GIC) in technological systems. This viewpoint means that the surface impedance is regarded as a tool to determine the horizontal (geo)electric field at the Earth's surface, which is the key quantity for GIC. Thus the approach is different from the traditional magnetotelluric viewpoint. The definition of the surface impedance usually involves wavenumber-frequency-domain fields, so inverse Fourier transforming the expression of the electric field in terms of the surface impedance and the geomagnetic field results in convolution integrals in the time and space domains. The frequency-dependent surface impedance has a high-pass filter character whereas the corresponding transfer function between the electric field and the time derivative of the magnetic field is of a low-pass filter type. The relative change of the latter transfer function with frequency is usually smaller than that of the surface impedance, which indicates that the geoelectric field is closer to the time derivative than to the magnetic field itself. An investigation of the surface impedance defined by the space-domain electric and magnetic components indicates that the largest electric fields are not always achieved by the plane wave assumption, which is sometimes regarded as an extreme case for GIC. It is also concluded in this paper that it is often possible to apply the plane wave relation locally between the surface electric and magnetic fields. The absolute value of the surface impedance decreases with an increasing wavenumber although the maximum may also be at a non-zero value of the wavenumber. The imaginary part of the surface impedance usually much exceeds the real part.

  15. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Science.gov (United States)

    Huang, Xianai; Kocaefe, Duygu; Kocaefe, Yasar; Boluk, Yaman; Krause, Cornélia

    2013-01-01

    Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  16. 2008 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Sondossi, Hoda A.; Hazel, Joseph E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.; Vanaman, Karen M.

    2009-01-01

    This report presents measurements of weather parameters and aeolian (windblown) sand transport made in 2008 near selected archaeological sites in the Colorado River corridor through Grand Canyon, Ariz. The quantitative methods and data discussed here form a basis for monitoring ecosystem processes that affect archeological-site stability. Combined with forthcoming work to evaluate landscape evolution at nearby archaeological sites, these data can be used to document the relationship between physical processes, including weather and aeolian sand transport, and their effects on the physical integrity of archaeological sites. Data collected in 2008 reveal event- and seasonal-scale variations in rainfall, wind, temperature, humidity, and barometric pressure. Broad seasonal changes in aeolian sediment flux are also apparent at most study sites. The continuation of monitoring that began in 2007, and installation of equipment at several new sites in early 2008, allowed evaluation of the effects of the March 2008 high-flow experiment (HFE) on aeolian sand transport. At two of the nine sites studied, spring and summer winds reworked 2008 HFE sandbars to form new aeolian dunes, at which sand moved inland toward larger, well-established dune fields. At the other seven study sites, neither dune formation nor enhanced sand transport after the HFE were observed. At several of those sites, dominant wind directions in spring 2008 were not oriented such that much HFE sand would have moved inland; at other sites, lack of increased inland sand flux is attributable to lack of sandbar enlargement near the study sites or to inhibition of sand movement by vegetation or local topography.

  17. Paleomagnetic dating of paleo-weathering surfaces, North America and Scotland

    Science.gov (United States)

    Dulin, S. A.; Elmore, R. D.; Parnell, J.

    2013-12-01

    Permian-Triassic chemical remanent magnetizations (CRMs) have been reported in basement rocks below weathering surfaces in continental Europe and North America, and are attributed to weathering fluids which caused precipitation of authigenic hematite. Identification and dating of these paleotopographic surfaces can have implications for climatic conditions during the weathering event. In this study we report paleomagnetic and petrographic results from unconformity surfaces in North America and Scotland to determine the characteristics and extent of this weathering event. Red granites from the Wichita Mountains in southern Oklahoma hold a CRM in hematite that is late Permian in age. The red granites represent a weathering profile that is seen in the upper 200m of the granites, and is present throughout the Wichita Mountains. On the Kintyre peninsula in Scotland, reddened Dalradian schist below an unconformity overlain by Permian-Triassic sandstones contains a late Permian-early Triassic CRM with southwesterly declinations and up inclinations (D = 184.6°, I = -33.3°). The CRM resides in hematite that is intergrown with dolomite. The overlying red sandstone has a similar CRM. Grey Dalradian schist contains magnetite but does not contain a stable magnetization. At another locality, reddened and dolomitized Dalradian schist below an unconformity overlain by the Devonian Old Red Sandstone contains a CRM with northeasterly declinations and down inclinations. The Devonian sandstones contain a CRM with southwesterly declinations and moderate up inclinations that are approximately antipodal to the CRM in the schist. The CRMs in the schist and sandstones reside in hematite. The fluids which caused remagnetization must have penetrated below the Permian unconformity into the Devonian unconformity. Other unconformity surfaces in Scotland (Cambrian-Lewisian; Triassic-Torridonian; Torridonian-Lewisian) are also being investigated as part of this study to determine if similar

  18. Final Project Report: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Jon Chorover, University of Arizona; Peggy O' €™Day, University of California, Merced; Karl Mueller, Penn State University; Wooyong Um, Pacific Northwest National Laboratory; Carl Steefel, Lawrence Berkeley National Laboratory

    2012-10-01

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided detailed characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions.

  19. Aspheric surface testing by irradiance transport equation

    Science.gov (United States)

    Shomali, Ramin; Darudi, Ahmad; Nasiri, Sadollah; Asgharsharghi Bonab, Armir

    2010-10-01

    In this paper a method for aspheric surface testing is presented. The method is based on solving the Irradiance Transport Equation (ITE).The accuracy of ITE normally depends on the amount of the pick to valley of the phase distribution. This subject is investigated by a simulation procedure.

  20. Energy balance of a glacier surface: analysis of Automatic Weather Station data from the Morteratschgletscher, Switzerland

    NARCIS (Netherlands)

    Oerlemans, J.; Klok, E.J.

    2002-01-01

    We describe and analyze a complete 1-yr data set from an automatic weather station (AWS) located on the snout of the Morteratschgletscher, Switzerland. The AWS stands freely on the glacier surface and measures pressure, windspeed, wind direction, air temperature and humidity, incoming and reflected

  1. Portland IAP, Portland, Oregon. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1980-09-08

    For theComiade I U’"S AMR FORCE u’S TECNICA REVISED UNIFORM SUMMARY APPLI CAIONS CEM0R OF SURFACE WEATHER OBSERVATIONS I, HOURLY OBSERVATIONS Hourly...ALL ’ i STATION STATION NAME ,e O L PERCENTAGE. FREQUENCY OF OCCURRENCE OF WEATH’ER i CONDITIONS FROM HOURLY OBSERVATIONS , "ii ONT HORS HUNER - RAIN

  2. Magnetic Flux Transport at the Solar Surface

    CERN Document Server

    Jiang, J; Cameron, R H; Solanki, S K; Gizon, L; Upton, L

    2014-01-01

    After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One is that the surface field, and its dynamics, sets the boundary condition for the coronal and heliospheric magnetic fields. Another is that the surface evolution gives us insight into the dynamo process. In particular, it plays an essential role in the Babcock-Leighton model of the solar dynamo. Describing this evolution is the aim of the surface flux transport model. The model starts from the emergence of magnetic bipoles. Thereafter, the model is based on the induction equation and the fact that after emergence the magnetic field is observed to evolve as if it were purely radial. The induction equation then describes how the surface flows -- differential rotation, meridional circulation, granular, supergranular flows, and active region inflows -- determine the evolution of the field (now taken to be purely radial). In this paper, we...

  3. INFLUENCE OF SEDIMENT TRANSPORT ON ARMORED SURFACES

    Institute of Scientific and Technical Information of China (English)

    Katinka KOLL; Andreas DITTRICH

    2001-01-01

    Laboratory experiments have been carried out to study the characteristics of sediment transport in steep streams. The question is discussed wether an armoured surfaces is destroyed due to the transport of material, because additional impulses are acting on it, or the layer is sheltered by the transported material, because a part of the stream power is used to move the material. According to the results of the presented experiments, in which the influence of the feeding rate and the feeding duration have been investigated, transported material reaching an armoured river section from upstream always remobilzes bed material, which is immobile under clear water flow conditions. To decide if a static armour layer is either destroyed or not, two simple criteria were chosen: oneconsidering the grain-size distribution of the eroded bed material, and another, which referes to the amount of eroded bed material.

  4. EVALUATION OF SURFACE QUALITY OF MEDIUM DENSITY FIBERBOARDS (MDF AND PARTICLEBOARDS AS FUNCTION OF WEATHERING

    Directory of Open Access Journals (Sweden)

    Aniela GARCIA PEREZ

    2012-12-01

    Full Text Available The objective of the study was to evaluate thesurface quality of commercially producedparticleboard and medium density fiberboard (MDFpanels as function of weathering. Four types ofpanels were exposed to three weathering cycles ofwater soaking, freezing, and heat exposures todetermine the influence of such conditions on theirsurface roughness. The stylus type equipment wasemployed to determine the roughness of controlsamples as well as after each one of the weatheringcycle. Two accepted roughness parameters, namelyaverage roughness (Ra and mean peak-to-valleyheight (Rz were used for the measurement of overallroughness changes of the specimens. Surfaces ofboth types of particleboard samples were adverselyinfluenced as a result of first cycle of weathering andthen they were reconditioned and subjected to twomore exposure cycles. In the case of MDF samplesthe first and the second weathering exposuresincreased roughness of the samples but they wererebalanced at the end of the third cycle. The highestRa value of 17.16μm was determined forparticleboard samples exposed to the first exposurecycle. Overall surface quality of MDF samples wereless influenced than those of particleboardspecimens. Based on the findings in this work itappears that stylus technique can effectively be usedto evaluate surface quality of such composite panelsas they are subjected to different weatheringexposures.

  5. Mars surface weathering products and spectral analogs: Palagonites and synthetic iron minerals

    Science.gov (United States)

    Golden, D. C.; Ming, D. W.; Morris, R. V.; Lauer, H. V., Jr.

    1992-01-01

    There are several hypotheses regarding the formation of Martian surface fines. These surface fines are thought to be products of weathering processes occurring on Mars. Four major weathering environments of igneous rocks on Mars have been proposed; (1) impact induced hydrothermal alterations; (2) subpermafrost igneous intrusion; (3) solid-gas surface reactions; and (4) subaerial igneous intrusion over permafrost. Although one or more of these processes may be important on the Martian surface, one factor in common for all these processes is the reaction of solid or molten basalt with water (solid, liquid, or gas). These proposed processes, with the exception of solid-gas surface reactions, are transient processes. The most likely product of transient hydrothermal processes are layer silicates, zeolites, hydrous iron oxides and palagonites. The long-term instability of hydrous clay minerals under present Martian conditions has been predicted; however, the persistence of such minerals due to slow kinetics of dehydration, or entrapment in permafrost, where the activity of water is high, can not be excluded. Anhydrous oxides of iron (e.g., hematite and maghemite) are thought to be stable under present Martian surface conditions. Oxidative weathering of sulfide minerals associated with Martian basalts has been proposed. Weathering of sulfide minerals leads to a potentially acidic permafrost and the formation of Fe(3) oxides and sulfates. Weathering of basalts under acidic conditions may lead to the formation of kaolinite through metastable halloysite and metahalloysite. Kaolinite, if present, is thought to be a thermodynamically stable phase at the Martian surface. Fine materials on Mars are important in that they influence the surface spectral properties; these fines are globally distributed on Mars by the dust storms and this fraction will have the highest surface area which should act as a sink for most of the absorbed volatiles near the surface of Mars. Therefore

  6. Approach to Integrate Global-Sun Models of Magnetic Flux Emergence and Transport for Space Weather Studies

    Science.gov (United States)

    Mansour, Nagi N.; Wray, Alan A.; Mehrotra, Piyush; Henney, Carl; Arge, Nick; Godinez, H.; Manchester, Ward; Koller, J.; Kosovichev, A.; Scherrer, P.; Zhao, J.; Stein, R.; Duvall, T.; Fan, Y.

    2013-01-01

    The Sun lies at the center of space weather and is the source of its variability. The primary input to coronal and solar wind models is the activity of the magnetic field in the solar photosphere. Recent advancements in solar observations and numerical simulations provide a basis for developing physics-based models for the dynamics of the magnetic field from the deep convection zone of the Sun to the corona with the goal of providing robust near real-time boundary conditions at the base of space weather forecast models. The goal is to develop new strategic capabilities that enable characterization and prediction of the magnetic field structure and flow dynamics of the Sun by assimilating data from helioseismology and magnetic field observations into physics-based realistic magnetohydrodynamics (MHD) simulations. The integration of first-principle modeling of solar magnetism and flow dynamics with real-time observational data via advanced data assimilation methods is a new, transformative step in space weather research and prediction. This approach will substantially enhance an existing model of magnetic flux distribution and transport developed by the Air Force Research Lab. The development plan is to use the Space Weather Modeling Framework (SWMF) to develop Coupled Models for Emerging flux Simulations (CMES) that couples three existing models: (1) an MHD formulation with the anelastic approximation to simulate the deep convection zone (FSAM code), (2) an MHD formulation with full compressible Navier-Stokes equations and a detailed description of radiative transfer and thermodynamics to simulate near-surface convection and the photosphere (Stagger code), and (3) an MHD formulation with full, compressible Navier-Stokes equations and an approximate description of radiative transfer and heating to simulate the corona (Module in BATS-R-US). CMES will enable simulations of the emergence of magnetic structures from the deep convection zone to the corona. Finally, a plan

  7. Solar wind interaction with the Reiner Gamma crustal magnetic anomaly: Connecting source magnetization to surface weathering

    Science.gov (United States)

    Poppe, Andrew R.; Fatemi, Shahab; Garrick-Bethell, Ian; Hemingway, Doug; Holmström, Mats

    2016-03-01

    Remanent magnetization has long been known to exist in the lunar crust, yet both the detailed topology and ultimate origin(s) of these fields remains uncertain. Some crustal magnetic fields coincide with surface albedo anomalies, known as lunar swirls, which are thought to be formed by differential surface weathering of the regolith underlying crustal fields due to deflection of incident solar wind protons. Here, we present results from a three-dimensional, self-consistent, plasma hybrid model of the solar wind interaction with two different possible source magnetizations for the Reiner Gamma anomaly. We characterize the plasma interaction with these fields and the resulting spatial distribution of charged-particle weathering of the surface and compare these results to optical albedo measurements of Reiner Gamma. The model results constrain the proposed source magnetizations for Reiner Gamma and suggest that vertical crustal magnetic fields are required to produce the observed "dark lanes."

  8. Glyphosate transport through weathered granite soils under irrigated and non-irrigated conditions--Barcelona, Spain.

    Science.gov (United States)

    Candela, Lucila; Caballero, Juan; Ronen, Daniel

    2010-05-15

    The transport of Glyphosate ([N-phosphonomethyl] glycine), AMPA (aminomethylphosphonic acid, CH(6)NO(3)P), and Bromide (Br(-)) has been studied, in the Mediterranean Maresme area of Spain, north of Barcelona, where groundwater is located at a depth of 5.5m. The unsaturated zone of weathered - granite soils was characterized in adjacent irrigated and non-irrigated experimental plots where 11 and 10 boreholes were drilled, respectively. At the non irrigated plot, the first half of the period was affected by a persistent and intense rainfall. After 69 days of application residues of Glyphosate up to 73.6 microgg(-1) were detected till a depth of 0.5m under irrigated conditions, AMPA, analyzed only in the irrigated plot was detected till a depth of 0.5m. According to the retardation coefficient of Glyphosate as compared to that of Br(-) for the topsoil and subsoil (80 and 83, respectively) and the maximum observed migration depth of Br(-) (2.9 m) Glyphosate and AMPA should have been detected till a depth of 0.05 m only. Such migration could be related to the low content of organic matter and clays in the soils; recharge generated by irrigation and heavy rain, and possible preferential solute transport and/or colloidal mediated transport. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Tropical Ocean Surface Energy Balance Variability: Linking Weather to Climate Scales

    Science.gov (United States)

    Roberts, J. Brent; Clayson, Carol Anne

    2013-01-01

    Radiative and turbulent surface exchanges of heat and moisture across the atmosphere-ocean interface are fundamental components of the Earth s energy and water balance. Characterizing the spatiotemporal variability of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-ocean feedbacks, and improving model predictability. These fluxes are integral components to tropical ocean-atmosphere variability; they can drive ocean mixed layer variations and modify the atmospheric boundary layer properties including moist static stability, thereby influencing larger-scale tropical dynamics. Non-parametric cluster-based classification of atmospheric and ocean surface properties has shown an ability to identify coherent weather regimes, each typically associated with similar properties and processes. Using satellite-based observational radiative and turbulent energy flux products, this study investigates the relationship between these weather states and surface energy processes within the context of tropical climate variability. Investigations of surface energy variations accompanying intraseasonal and interannual tropical variability often use composite-based analyses of the mean quantities of interest. Here, a similar compositing technique is employed, but the focus is on the distribution of the heat and moisture fluxes within their weather regimes. Are the observed changes in surface energy components dominated by changes in the frequency of the weather regimes or through changes in the associated fluxes within those regimes? It is this question that the presented work intends to address. The distribution of the surface heat and moisture fluxes is evaluated for both normal and non-normal states. By examining both phases of the climatic oscillations, the symmetry of energy and water cycle responses are considered.

  10. Turbulent transport in the atmospheric surface layer

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Science, Lund Univ., Lund (Sweden)

    2012-04-15

    In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to {approx}3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect

  11. Turbulent transport in the atmospheric surface layer

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Science, Lund Univ., Lund (Sweden)

    2012-04-15

    In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to {approx}3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect

  12. Effects of UV weathering on surface properties of polypropylene composites reinforced with wood flour, lignin, and cellulose

    Science.gov (United States)

    Peng, Yao; Liu, Ru; Cao, Jinzhen; Chen, Yu

    2014-10-01

    In this study, the influence of accelerated weathering on polypropylene composites reinforced with wood flour (WF), lignin, and cellulose at different loading levels were evaluated. Six groups of samples were exposed in a QUV accelerated weathering tester for a total of 960 h. The surface color, surface gloss, contact angle and flexural properties of the samples were tested. Besides, the weathered surface was characterized by SEM and ATR-FTIR. The results revealed that (1) the discoloration of composites was accelerated by the presence of lignin, especially at high content; (2) composites containing lignin showed less loss of flexural strength and modulus, less cracks, and better hydrophobicity on weathered surface than other groups, confirming its functions of stabilization and antioxidation; (3) cellulose-based composites exhibited better color stability but more significant deterioration in flexural properties after weathering compared to other composites, suggesting that such kind of composites could not be used as load-bearing structure in outdoor applications.

  13. Temperature and Relative Humidity Inside Trailers During Finishing Pig Loading and Transport in Cold and Mild Weather

    Directory of Open Access Journals (Sweden)

    John McGlone

    2014-09-01

    Full Text Available The effect of bedding levels and trailer compartment on internal trailer temperature and relative humidity (RH during loading and transport of finishing pigs was evaluated in cold and mild weather. Three levels of bedding were used in each experiment: 0.6 m3, 1.2 m3, and 2.4 m3. In mild weather, internal temperatures were lower when 1.2 m3 or 2.4 m3 of bedding were used during loading and transport compared to 0.6 m3 (P < 0.05. Internal trailer temperature increased in a quadratic fashion in the top front compartment when 1.2 m3 was used (P < 0.05, and in a linear fashion in the top rear compartment when 2.4 m3 were used in cold weather (P < 0.05. In mild weather, temperature increased linearly in the top front compartment with heavy bedding levels. Relative humidity increased in a linear fashion in the top front compartment with 0.6 m3, bottom front with 1.2 m3, and top front with 1.2 m3 in cold weather (P < 0.05. In general, temperature and RH increased as bedding levels increased in both cold and mild temperatures. Excess bedding can absorb more moisture, resulting in transport loss and decreased animal welfare.

  14. Space Weathering Impact on Solar System Surfaces and Planetary Mission Science

    Science.gov (United States)

    Cooper, John F.

    2011-01-01

    We often look "through a glass, darkly" at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compOSitional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer

  15. From the surface to the deep critical zone: Linking soil carbon, fluid saturation and weathering rate

    Science.gov (United States)

    Druhan, Jennifer; Lawrence, Corey; Oster, Jessica; Rempe, Daniella; Dietrich, William

    2017-04-01

    Shallow soils from a wide range of ecosystems demonstrate a clear and consistent relationship between effective fluid saturation and the rate at which organic carbon is converted to CO2. While the underlying mechanisms contributing to this dependence are diverse, a consistent pattern of maximum CO2 production at intermediate soil moisture supports a generalized functional relationship, which may be incorporated into a quantitative reactive transport framework. A key result of this model development is a prediction of the extent to which the inorganic carbon content of water in biologically active soils varies as a function of hydrologic parameters (i.e. moisture content and residence time), and in turn influences weathering reactions. Deeper in the CZ, the consistency of this relationship and the influence of hydrologically - regulated CO2 production on the rates of water - rock interaction are largely unknown. Here, we use a novel reactive transport model incorporating this functional relationship to consider how variations in the reactive potential of water entering the vadose zone influences subsurface weathering rates. We leverage two examples of variably saturated natural systems to consider (1) CO2 production and associated weathering potential regulated by seasonal hydrologic shifts and (2) the preservation of soil carbon signatures in the deep CZ over millennial timescales. First, at the Eel River CZ Observatory in Northern California, USA, a novel Vadose Zone Monitoring System (VMS) installed in a 14 - 20 m thick unsaturated section offers an unprecedented view into the physical, chemical and biological behavior of the depth profile separating soils from groundwater. Based on soil moisture, gas and fluid phase samples, we demonstrate a predictive relationship between seasonal hydrologic variations and the location and magnitude of geochemical weathering rates. Second, an environmental monitoring project in the Blue Springs Cave, Sparta, TN, USA, provides

  16. 29 CFR 1926.902 - Surface transportation of explosives.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Surface transportation of explosives. 1926.902 Section 1926... Explosives § 1926.902 Surface transportation of explosives. (a) Transportation of explosives shall meet the... Carriers. (b) Motor vehicles or conveyances transporting explosives shall only be driven by, and be in the...

  17. Characterization of surface chemistry and crystallization behavior of polypropylene composites reinforced with wood flour, cellulose, and lignin during accelerated weathering

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Yao; Liu, Ru; Cao, Jinzhen, E-mail: caoj@bjfu.edu.cn

    2015-03-30

    Highlights: • AFM was firstly used to characterize the surface morphology and roughness of weathered wood–plastic composites. • Composites containing lignin showed less loss of flexural strength and modulus and less roughness on weathered surface compared with lignin-free composites. • ATR-FTIR and XPS analyses demonstrated in detail that significant chemistry changes occurred in wood flour, lignin, and cellulose. • The crystallinity of PP increased in all weathered samples due to chain scissions and recrystallization. • The stabilization and antioxidation effects of lignin were proved. - Abstract: In this study, six groups of polypropylene composites reinforced with wood flour (WF), cellulose, and lignin at different loading levels were exposed in a QUV accelerated weathering tester for a total duration of 960 h. The changes in surface morphology, chemistry, and thermal properties of weathered samples were characterized by atomic force microscope (AFM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetric (DSC), respectively. The flexural properties of all samples were tested after different durations of weathering. The results showed that: (1) the surface roughness of all samples increased after weathering; (2) composites containing lignin showed less loss of flexural strength and modulus and less roughness on weathered surface compared with lignin-free composites, indicating the functions of stabilization and antioxidation of lignin; (3) the crystallinity of PP increased in all weathered samples due to chain scissions and recrystallization; (4) ATR-FTIR and XPS analyses demonstrated in detail that significant changes occurred in surface chemistry, accompanied by the photodegradation and photo-oxidation of lignin and cellulose with prolonged weathering time.

  18. Coal mine spoil-water interaction: Ⅱ. Weathering concentrated metals in surface coal mine spoils

    Institute of Scientific and Technical Information of China (English)

    党志; 万国江; 李德忍

    1996-01-01

    Concentrations of metals are lower in coal shales collected from recently exposed surface mine wastes than in shales collected from spoils exposed to surface weathering for 45 a. In this period, the character of the spoils changes dramatically as a result of the accelerated breakdown of the freshly exposed minestones. Since the metals are held as unstable sulfides, it is suggested that enrichment may be caused by absorption of metals by colloid of iron or formation of organic complex compound with organic carbon existing in the remnant structure of coal mine spoil. This process may contribute to the triggering of soil contamination thresholds on coal-lands already heavily loaded with metals.

  19. A much warmer Earth surface for most of geologic time: implications to biotic weathering

    Science.gov (United States)

    Schwartzman, D. W.; McMenamin, M.

    1993-01-01

    The authors present two scenarios for the temperature history of Earth. One scenario is conventional, the other relies on a warmer history. Both scenarios include surface cooling determined by the evolution of the biosphere and are similar until the Proterozoic period. The warmer scenario requires a higher plant/lichen terrestrial biota to increase weathering intensity. Justification for a warmer surface includes period temperatures from the oxygen isotope record of coexisting phosphates and cherts, an upper limit of 58 degrees C from primary gypsum precipitation, and the lack of fractionation of sulfur isotopes between sulfide and sulfates in Archean sediments.

  20. A much warmer Earth surface for most of geologic time: implications to biotic weathering

    Science.gov (United States)

    Schwartzman, D. W.; McMenamin, M.

    1993-01-01

    The authors present two scenarios for the temperature history of Earth. One scenario is conventional, the other relies on a warmer history. Both scenarios include surface cooling determined by the evolution of the biosphere and are similar until the Proterozoic period. The warmer scenario requires a higher plant/lichen terrestrial biota to increase weathering intensity. Justification for a warmer surface includes period temperatures from the oxygen isotope record of coexisting phosphates and cherts, an upper limit of 58 degrees C from primary gypsum precipitation, and the lack of fractionation of sulfur isotopes between sulfide and sulfates in Archean sediments.

  1. Potential crop evapotranspiration and surface evaporation estimates via a gridded weather forcing dataset

    Science.gov (United States)

    Lewis, Clayton S.; Allen, L. Niel

    2017-03-01

    Absent local weather stations, a gridded weather dataset can provide information useful for water management in irrigated areas including potential crop evapotranspiration calculations. In estimating crop irrigation requirements and surface evaporation in Utah, United States of America, methodology and software were developed using the ASCE Standardized Penman-Monteith Reference Evapotranspiration equation with input climate drivers from the North American Land Data Assimilation System (NLDAS) gridded weather forcing dataset and a digital elevation model. A simple procedure was devised to correct bias in NLDAS relative humidity and air temperature data based on comparison to weather data from ground stations. Potential evapotranspiration was calculated for 18 crops (including turfgrass), wetlands (large and narrow), and open water evaporation (deep and shallow) by multiplying crop coefficient curves to reference evapotranspiration with annual curve dates set by summation of Hargreaves evapotranspiration, cumulative growing degree days, or number of days. Net potential evapotranspiration was calculated by subtracting effective precipitation estimates from the Daymet gridded precipitation dataset. Analysis of the results showed that daily estimated potential crop evapotranspiration from the model compared well with estimates from electronic weather stations (1980-2014) and with independently calculated potential crop evapotranspiration in adjacent states. Designed for this study but open sourced for other applications, software entitled GridET encapsulated the GIS-based model that provided data download and management, calculation of reference and potential crop evapotranspiration, and viewing and analysis tools. Flexible features in GridET allows a user to specify grid resolution, evapotranspiration equations, cropping information, and additional datasets with the output being transferable to other GIS software.

  2. Surface-Correlated Nanophase Iron Metal in Lunar Soils: Petrography and Space Weathering Effects

    Science.gov (United States)

    Keller, Lindsay P.; Wentworth, Susan J.; McKay, David S.

    1998-01-01

    Space weathering is a term used to include all of the processes that act on material exposed at the surface of a planetary or small body. In the case of the Moon, it includes a variety of processes that formed the lunar regolith, caused the maturation of lunar soils, and formed patina on rock surfaces. The processes include micrometeorite impact and reworking, implantation of solar wind and flare particles, radiation damage and chemical effects from solar particles and cosmic rays, interactions with the lunar atmosphere, and sputtering erosion and deposition. Space weathering effects collectively result in a reddened continuum slope, lowered albedo, and attenuated absorption features in reflectance spectra of lunar soils as compared to finely comminuted rocks from the same Apollo sites. Understanding these effects is critical in order to fully integrate the lunar sample collection with remotely sensed data from recent robotic missions (e.g., Lunar Prospector, Clementine, Galileo). Our objective is to determine the origin of space weathering effects in lunar soils through combined electron microscopy and microspectrophotometry techniques applied to individual soil particles from lunar soils. It has been demonstrated that it is the finest size fraction (lunar soils that dominates the optical properties of the bulk soils.

  3. Spectral properties of Titan's impact craters imply chemical weathering of its surface

    Science.gov (United States)

    Barnes, J. W.; Sotin, C.; MacKenzie, S.; Soderblom, J. M.; Le Mouélic, S.; Kirk, R. L.; Stiles, B. W.; Malaska, M. J.; Le Gall, A.; Brown, R. H.; Baines, K. H.; Buratti, B.; Clark, R. N.; Nicholson, P. D.

    2015-01-01

    Abstract We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions. PMID:27656006

  4. Dover AFB, Delaware Revised Uniform Summary of Surface Weather Observations (RUSSWO) Parts A-F.

    Science.gov (United States)

    1981-10-16

    UNIFORM SUMMARY A.PPLICATIONS CEPWER OF SURFACE WEATHER OBSERVATIONS HOURLY OBSERVATIONS _r_ )Lsr.a*o:Lt,- are ievuI~ td a~i ttnoz~ rtecord or record...STATION MNS YEANS MONTH ALL WEATHER A LL CLASS Noun$ II..S.T.J CONDITION SPEED MEAN IKNTS) 1.3 4.6 7-10 It1-16 17.21 22-27 2533 34.40 41-.47 48.55 td ...704 _24 .U 59 17 ~9 6 99 ] 0Kk 5. _1 1 0_ 42.7 - 4 . ,, 13.4, 3 6 7 - 11 ,,. - 9 -17@539. 5’,_ 7 7 li. 7.a91 22a. 57e~9, -"eB .e 344 9~9 2~ 9*2 59.c 5

  5. Characterization of the role of heterogeneous advection and diffusion on transport in weathered and fractured granite

    Science.gov (United States)

    Guihéneuf, N.; Boisson, A.; Bour, O.; Le Borgne, T.; Marechal, J.; Nigon, B.; Wajiddudin, M.; Ahmed, S.

    2013-12-01

    The prediction of transport in weathered and fractured rocks is critical as it represents the primary control of contaminant transfer from the subsurface in many parts of the world. This is the case in Southern India, where the subsurface is composed mainly of weathered and fractured granite and where the overexploitation of the groundwater resource since the 70's has led to high water table depletion and strong groundwater quality deterioration. One key issue for modelling transport in such systems is to quantify the respective role of advective heterogeneities and matrix diffusion, which can both lead to strongly non Fickian transport properties. We investigate this question by analysing tracer test experiments performed under different flow configurations at a fractured granite experimental site located in Andhra Pradesh (India). We performed both convergent and push-pull tracer tests within the same fracture and at different scales. Three convergent tracer tests were performed with a solution of fluorescein for different pumping rate and for different distances between injection and pumping boreholes: 6, 30 and 41 meters. To evaluate diffusive process, we performed two long-duration push-pull tests (push time of 3 hours) with a solution of two conservative tracers of different diffusion coefficient (fluorescein and sodium chloride). We performed also six others push-pull tests with only fluorescein but for a variable push times of 14 min and 55 min with or without resting time of about 60 min. The late-time behaviour on the breakthrough curves (BTCs) obtained for all convergent tracer tests showed a power-law slope of -2. Two of them showed an inflexion in the BTCs suggesting the existence of two independent flow paths and thus a highly channelized flow. The long-duration push-pull tests showed similar late-time behaviour with a power-law slope of -2.2 for both tracers. The six others push-pull tests showed a variation of power-law exponent from -3 to -2

  6. Biochemical evolution II: origin of life in tubular microstructures on weathered feldspar surfaces.

    Science.gov (United States)

    Parsons, I; Lee, M R; Smith, J V

    1998-12-22

    Mineral surfaces were important during the emergence of life on Earth because the assembly of the necessary complex biomolecules by random collisions in dilute aqueous solutions is implausible. Most silicate mineral surfaces are hydrophilic and organophobic and unsuitable for catalytic reactions, but some silica-rich surfaces of partly dealuminated feldspars and zeolites are organophilic and potentially catalytic. Weathered alkali feldspar crystals from granitic rocks at Shap, north west England, contain abundant tubular etch pits, typically 0.4-0.6 microm wide, forming an orthogonal honeycomb network in a surface zone 50 microm thick, with 2-3 x 10(6) intersections per mm2 of crystal surface. Surviving metamorphic rocks demonstrate that granites and acidic surface water were present on the Earth's surface by approximately 3.8 Ga. By analogy with Shap granite, honeycombed feldspar has considerable potential as a natural catalytic surface for the start of biochemical evolution. Biomolecules should have become available by catalysis of amino acids, etc. The honeycomb would have provided access to various mineral inclusions in the feldspar, particularly apatite and oxides, which contain phosphorus and transition metals necessary for energetic life. The organized environment would have protected complex molecules from dispersion into dilute solutions, from hydrolysis, and from UV radiation. Sub-micrometer tubes in the honeycomb might have acted as rudimentary cell walls for proto-organisms, which ultimately evolved a lipid lid giving further shelter from the hostile outside environment. A lid would finally have become a complete cell wall permitting detachment and flotation in primordial "soup." Etch features on weathered alkali feldspar from Shap match the shape of overlying soil bacteria.

  7. Characterization of surface chemistry and crystallization behavior of polypropylene composites reinforced with wood flour, cellulose, and lignin during accelerated weathering

    Science.gov (United States)

    Peng, Yao; Liu, Ru; Cao, Jinzhen

    2015-03-01

    In this study, six groups of polypropylene composites reinforced with wood flour (WF), cellulose, and lignin at different loading levels were exposed in a QUV accelerated weathering tester for a total duration of 960 h. The changes in surface morphology, chemistry, and thermal properties of weathered samples were characterized by atomic force microscope (AFM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetric (DSC), respectively. The flexural properties of all samples were tested after different durations of weathering. The results showed that: (1) the surface roughness of all samples increased after weathering; (2) composites containing lignin showed less loss of flexural strength and modulus and less roughness on weathered surface compared with lignin-free composites, indicating the functions of stabilization and antioxidation of lignin; (3) the crystallinity of PP increased in all weathered samples due to chain scissions and recrystallization; (4) ATR-FTIR and XPS analyses demonstrated in detail that significant changes occurred in surface chemistry, accompanied by the photodegradation and photo-oxidation of lignin and cellulose with prolonged weathering time.

  8. Surface degradation of CeO2 stabilized acrylic polyurethane coated thermally treated jack pine during accelerated weathering

    Science.gov (United States)

    Saha, Sudeshna; Kocaefe, Duygu; Boluk, Yaman; Pichette, Andre

    2013-07-01

    The thermally treated wood is a new value-added product and is very important for the diversification of forestry products. It drew the attention of consumers due to its attractive dark brown color. However, it loses its color when exposed to outside environment. Therefore, development of a protective coating for this value added product is necessary. In the present study, the efficiency of CeO2 nano particles alone or in combination with lignin stabilizer and/or bark extracts in acrylic polyurethane polymer was investigated by performing an accelerated weathering test. The color measurement results after accelerated weathering demonstrated that the coating containing CeO2 nano particles was the most effective whereas visual assessment suggested the coating containing CeO2 nano particles and lignin stabilizer as the most effective coating. The surface polarity changed for all the coatings during weathering and increase in contact angle after weathering suggested cross linking and reorientation of the polymer chain during weathering. The surface chemistry altered during weathering was evaluated by ATR-FTIR analysis. It suggested formation of different carbonyl byproducts during weathering. The chain scission reactions of the urethane linkages were not found to be significant during weathering.

  9. INTRAVAL phase 2, test case 8, Alligator Rivers Natural Analogue: Modelling of uranium transport in the weathered zone at Koongarra (Australia)

    Energy Technology Data Exchange (ETDEWEB)

    Van de Weerd, H.; Leijnse, A.; Hassanizadeh, S.M.; Richardson-van der Poel, M.A.

    1994-04-01

    The purpose of this study is to test the simulation package METROPOL, developed at RIVM to simulate transport of radionuclides over large time scales. At the Koongarra site secondary uranium mineralization and dispersed uranium is present from the surface down to the base of weathering. Field data are analyzed to choose a modelling approach, to estimate model inputs and to test model results. Field data show that three layers can be distinguished in the Koongarra area: (1) a top layer which is fully weathered, (2) an intermediate layer which is partially weathered (the transition zone) and (3) a lower layer which is unweathered. The groundwater velocities are largest in the transition zone which has been moving downward as the weathering process proceeds. The finite element code METROPOL has been adapted to account for the movement of the transition zone and to describe the dissolution of uranium in the orebody by a non-equilibrium relation. In simulations taking into account the downward movement of the transition zone, the dispersion patterns at all depths are simulated. These simulations result in a pseudo steady state situation. Despite the fact that the model results presented are not fully in agreement with the dispersion patterns, it is expected that the present situation may be obtained by changing some of the model parameters. In this study it was shown that over large timescales geologic processes may have an impact on the transport of radionuclides, and the movement of the transition zone will have an impact on the uranium concentration distribution. The simulation results are influenced by the parameters values, which are difficult to estimate for a period of some million years. The largest uncertainties are associated with the boundary conditions. Continuation of natural analogue studies in the framework of nuclear waste disposal research is highly recommended. 24 figs., 13 tabs., 2 appendices, 39 refs.

  10. Surface area dependence of calcium isotopic reequilibration in carbonates: Implications for isotopic signatures in the weathering zone

    Science.gov (United States)

    Fernandez, N. M.; Druhan, J. L.; Potrel, A.; Jacobson, A. D.

    2016-12-01

    The concept of dynamic equilibrium carries the implicit assumption of continued isotopic exchange between a mineral and the surrounding fluid. While this effect has received much attention in the marine paleoproxy literature, it has been relatively overlooked in application to the terrestrial environment. In weathering systems, a potential consequence is that rapid reequilibration may alter or erase isotopic signatures generated during secondary mineral formation. The extent and timescale over which isotopic signatures are reset in these hydrologic systems is unknown. Using reactive transport modeling, we show isotopic reequilibration under conditions reflecting terrestrial hydrologic settings to be significant and dependent on the reactive surface area of the solid. In particular, we suggest that the non-traditional stable isotopes commonly used in application to carbonates (e.g., Ca, Mg, Sr) are sensitive to these effects due to their rapid reaction rates. We aim to characterize the dependence of Ca isotopic reequilibration on surface area during calcite precipitation via batch experiments conducted at ambient temperature over 48-hour time periods. Calcite precipitation was performed in a closed batch reactor utilizing a controlled free-drift method. The batch reactors contained mixed supersaturated solutions of CaCl2 and NaHCO3 at an initial pH of 8.54. Precipitation was initiated by seed inoculation of calcite crystals with two distinct, pre-constrained surface areas. All experiments achieved the same final state of chemical equilibrium, but as expected, the fastest approach to equilibrium occurred for experiments employing calcite seeds with the highest surface area. This implies that differences in equilibrated Ca isotope ratios (δ44/40Ca) should reflect differences in surface area. This prediction is upheld by models of the experiments, indicating a measureable difference in δ44Ca during calcite precipitation where the higher surface area corresponds to

  11. Characterizing Surface Transport Barriers in the South China Sea

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Characterizing Surface Transport Barriers in the South...in mathematical methods for detecting key Lagrangian transport structures in velocity field data sets for spatially complex, time- dependent, ocean...surface flows. Such transport structures are typically not inherently obvious in snapshots of the Eulerian velocity field and require analysis

  12. Surface dynamics of crude and weathered oil in the presence of dispersants: Laboratory experiment and numerical simulation

    Science.gov (United States)

    Soloviev, Alexander V.; Haus, Brian. K.; McGauley, Michael G.; Dean, Cayla W.; Ortiz-Suslow, David G.; Laxague, Nathan J. M.; Özgökmen, Tamay M.

    2016-05-01

    Marine oil spills can have dire consequences for the environment. Research on their dynamics is important for the well-being of coastal communities and their economies. Propagation of oil spills is a very complex physical-chemical process. As seen during the Deepwater Horizon event in the Gulf of Mexico during 2010, one of the critical problems remaining for prediction of oil transport and dispersion in the marine environment is the small-scale structure and dynamics of surface oil spills. The laboratory experiments conducted in this work were focused on understanding the differences between the dynamics of crude and weathered oil spills and the effect of dispersants. After deposition on the still water surface, a drop of crude oil quickly spread into a thin slick; while at the same time, a drop of machine (proxy for weathered) oil did not show significant evolution. Subsequent application of dispersant to the crude oil slick resulted in a quick contraction or fragmentation of the slick into narrow wedges and tiny drops. Notably, the slick of machine oil did not show significant change in size or topology after spraying dispersant. An advanced multi-phase, volume of fluid computational fluid dynamics model, incorporating capillary forces, was able to explain some of the features observed in the laboratory experiment. As a result of the laboratory and modeling experiments, the new interpretation of the effect of dispersant on the oil dispersion process including capillary effects has been proposed, which is expected to lead to improved oil spill models and response strategies.

  13. Controlling the potential hazards of government-sponsored technology. [such as weather modification and the supersonic transports

    Science.gov (United States)

    Wollan, M. J.

    1975-01-01

    The ability was examined of governmental agencies to adequately assess technological programs or projects to which they are committed. The hazards of government-sponsored activities are discussed; these include weather modification, supersonic transport noise, and the value conflicts involved in the fluoridation controversy. These three case studies indicate that the Federal vested interests in the continuation of its technological programs limit its ability to provide adequate technology assessment.

  14. How much does weather-driven vegetation dynamics matter in land surface modelling?

    Science.gov (United States)

    Ingwersen, Joachim; Streck, Thilo

    2016-04-01

    Land surface models (LSM) are an essential part of weather and climate models as they provide the lower boundary condition for the atmospheric models. In state-of-the-art LSMs the seasonal vegetation dynamics is "frozen". The seasonal variation of vegetation state variables, such as leaf area index or green vegetation fraction, are prescribed in lookup tables. Hence, a year-by-year variation in the development of vegetation due to changing weather conditions cannot be considered. For climate simulations, this is obviously a severe drawback. The objective of the present study was to quantify the potential error in the simulation of land surface exchange processes resulting from "frozen" vegetation dynamics. For this purpose we simulated energy and water fluxes from a winter wheat stand and a maize stand in Southwest Germany. In a first set of simulations, six years (2010 to 2015) were simulated considering weather-driven vegetation dynamics. For this purpose, we coupled the generic crop growth model GECROS with the NOAH-MP model (NOAHMP-GECROS). In a second set of simulations all vegetation-related state variables of the 2010 simulation were written to an external file and were used to overwrite the vegetation-related state variables of the simulations of the years 2011-2015. The difference between both sets was taken as a measure for the potential error introduced to the LSM due to the assumption of a "frozen" vegetation dynamics. We will present first results and discuss the impact of "frozen" vegetation dynamics on climate change simulations.

  15. Space Weathering Effects in Lunar Soils: The Roles of Surface Exposure Time and Bulk Chemical Composition

    Science.gov (United States)

    Zhang, Shouliang; Keller, Lindsay P.

    2011-01-01

    Space weathering effects on lunar soil grains result from both radiation-damaged and deposited layers on grain surfaces. Typically, solar wind irradiation forms an amorphous layer on regolith silicate grains, and induces the formation of surficial metallic Fe in Fe-bearing minerals [1,2]. Impacts into the lunar regolith generate high temperature melts and vapor. The vapor component is largely deposited on the surfaces of lunar soil grains [3] as is a fraction of the melt [4, this work]. Both the vapor-deposits and the deposited melt typically contain nanophase Fe metal particles (npFe0) as abundant inclusions. The development of these rims and the abundance of the npFe0 in lunar regolith, and thus the optical properties, vary with the soil mineralogy and the length of time the soil grains have been exposed to space weathering effects [5]. In this study, we used the density of solar flare particle tracks in soil grains to estimate exposure times for individual grains and then perform nanometer-scale characterization of the rims using transmission electron microscopy (TEM). The work involved study of lunar soil samples with different mineralogy (mare vs. highland) and different exposure times (mature vs. immature).

  16. Observed linear trend in few surface weather elements over the Northwest Himalayas (NWH) during winter season

    Indian Academy of Sciences (India)

    Dan Singh; Vikas Sharma; Vikas Juyal

    2015-04-01

    Linear trends in few surface weather variables such as air temperatures (maximum temperature, minimum temperature), snow and rainy days, snowfall and rainfall amounts, rainfall contribution to seasonal total precipitation amount, seasonal snow cover depth and snow cover days (duration) are examined from winter-time observations at 11 stations located over the Northwest Himalayas (NWH). This study indicates that snowfall tends to show a decline in this region, while the rainfall tends to increase during the winter months. Seasonal snow cover depth and seasonal snow cover days also tend to show a decline over the NWH. Decrease in seasonal snow cover depth and duration have reduced the winter period in terms of availability of seasonal snow cover over the NWH during the last 2–3 decades. Other surface weather variables also exhibited significant temporal changes in recent decades. Observed trends in temperature and precipitation over the NWH in recent decades are also supported by long data series of temperature over the western Himalayas (WH), north mountain India (NMI) rainfall data and reanalysis products.

  17. Recovery of Global Surface Weather Observations for Historical Reanalyses and International Users

    Science.gov (United States)

    Allan, Rob; Compo, Gil; Carton, Jim

    2011-05-01

    Third International Atmospheric Circulation Reconstructions Over the Earth Initiative Workshop: Reanalysis and Applications; Baltimore, Maryland, 3-5 November 2010 ; The third Atmospheric Circulation Reconstructions over the Earth (ACRE) workshop advanced the goals of the international ACRE initiative (http://www.met-acre.org/) to undertake and facilitate the recovery of instrumental terrestrial and marine global surface weather observations underpinning global weather reconstructions and reanalyses spanning the past 200-250 years (http://reanalyses.org). The workshop improved integration of the 35-40 ACRE-linked international scientific projects, institutions, and organizations working toward these ends. The meeting highlighted the broad array and international usage of ACRE-facilitated data sets and reanalysis: the International Surface Pressure Databank (ISPD; http://dss.ucar.edu/datasets/ds132.0/), the International Comprehensive Ocean-Atmosphere Data Set (http:/icoads.noaa.gov/ICOADS;), and the 20th Century Reanalysis (20CR; http://www.esrl.noaa.gov/psd/data/20thC_Rean/). The need for more data recovery for all regions of the globe during the nineteenth and early twentieth centuries was emphasized. Many regional efforts for such recovery are under way. The Arctic and maritime regions were highlighted as particular areas needing attention. As a result of the meeting, connections with existing projects were made and new efforts were started to address these needs.

  18. Weathering processes and the composition of inorganic material transported through the orinoco river system, Venezuela and Colombia

    Science.gov (United States)

    Stallard, R.F.; Koehnken, L.; Johnsson, M.J.

    1991-01-01

    The composition of river-borne material in the Orinoco River system is related primarily to erosion regime, which in turn is related to tectonic setting; especially notable is the contrast between material derived from tectonically active mountain belts and that from stable cratonic regions. For a particular morpho-tectonic region, the compositional suites of suspended sediment, bed material, overback deposits, and dissolved phases are fairly uniform are are typically distinct from whose of other regions. For each region, a consistent set of chemical weathering reactions can be formulated to explain the composition of dissolved and solid loads. In developing these formulations, erosion on slopes and storage of solids in soils and alluvial sediments are important considerations. Compositionally verymature sediment is derived from areas of thick soils where erosion is transport limited and from areas where sediments are stored for extended periods of time in alluvial deposits. Compositionally immature sediments are derived from tectonically active mountain belts where erosion is weathering limited. Weathering-limited erosion also is important in the elevated parts of the Guayana Shield within areas of sleep topography. Compared to the mountain belts, sediments derived from elevated parts of the Shield are more mature. A greater degree of chemical weathering seems to be needed to erode the rock types typical of the Shield. The major-element chemistry and mineral composition of sediment delivered by the Orinoco River to the ocean are controlled by rivers that have their headwaters in mountain belts and cross the Llanos, a region of alluvial plains within the foreland basin. The composition of sediments in rivers that drain the Shield seems to be established primarily at the site of soil formation, whereas for rivers that drain the mountain belts, additional weathering occurs during s episodes of storage on alluvial plains as sediments are transported across the Llanos

  19. Constraining storm-scale forecasts of deep convective initiation with surface weather observations

    Science.gov (United States)

    Madaus, Luke

    Successfully forecasting when and where individual convective storms will form remains an elusive goal for short-term numerical weather prediction. In this dissertation, the convective initiation (CI) challenge is considered as a problem of insufficiently resolved initial conditions and dense surface weather observations are explored as a possible solution. To better quantify convective-scale surface variability in numerical simulations of discrete convective initiation, idealized ensemble simulations of a variety of environments where CI occurs in response to boundary-layer processes are examined. Coherent features 1-2 hours prior to CI are found in all surface fields examined. While some features were broadly expected, such as positive temperature anomalies and convergent winds, negative temperature anomalies due to cloud shadowing are the largest surface anomaly seen prior to CI. Based on these simulations, several hypotheses about the required characteristics of a surface observing network to constrain CI forecasts are developed. Principally, these suggest that observation spacings of less than 4---5 km would be required, based on correlation length scales. Furthermore, it is anticipated that 2-m temperature and 10-m wind observations would likely be more relevant for effectively constraining variability than surface pressure or 2-m moisture observations based on the magnitudes of observed anomalies relative to observation error. These hypotheses are tested with a series of observing system simulation experiments (OSSEs) using a single CI-capable environment. The OSSE results largely confirm the hypotheses, and with 4-km and particularly 1-km surface observation spacing, skillful forecasts of CI are possible, but only within two hours of CI time. Several facets of convective-scale assimilation, including the need for properly-calibrated localization and problems from non-Gaussian ensemble estimates of the cloud field are discussed. Finally, the characteristics

  20. Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra

    Science.gov (United States)

    Kaňuchová, Z.; Baratta, G. A.; Garozzo, M.; Strazzulla, G.

    2010-07-01

    Context. The surfaces of airless bodies in the Solar System are continuously altered by the bombardment of micrometeoroids and irradiation by solar wind, flares, and cosmic particles. Major effects of this process - space weathering - are darkening and “reddening” of the spectra of surface materials, as well as a “degrading” of absorption features. Aims: We studied the changes induced by energetic ion irradiation in the ultraviolet-visual-near-infrared (UV-Vis-NIR) (0.2-0.98 μm) reflectance spectra of targets selected to mimic the surfaces of airless bodies in the inner Solar System. Our chosen targets are olivine pellets, pure or covered by an organic polymer (polystyrene), which is transparent before irradiation. Polystyrene is used as a template for organic matter of low volatility that can be present on asteroidal surfaces. Moreover we measured the changes induced by ion irradiation in the absorption coefficient of the polymer. The purpose was to have a tool to better compare laboratory with observed spectra and distinguish between planetary objects with pure silicate surfaces and those whose surface is covered by organic matter exposed to cosmic ion bombardment. Methods: The samples were irradiated in vacuum, at room temperature, with 200 keV protons or 200-400 keV argon ions. Before, during, and after irradiation diffuse reflectance spectra were acquired. Polystyrene films were also deposited on quartz substrates and irradiated while transmittance spectra were recorded. Results: We measured the variations of the absorption coefficient of polystyrene as a function of ion fluence. We showed that after ion irradiation the diffuse reflectance spectra of the samples covered by organics exhibit a much more significant variation than those of pure silicates. The spectra of targets made of olivine plus polystyrene can be fitted by using the measured absorption coefficient of polystyrene. Conclusions: The results obtained for pure olivine extend to the UV the

  1. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    Science.gov (United States)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  2. Understanding the roles of ligand promoted dissolution, water column saturation and hydrological properties on intense basalt weathering using reactive transport and watershed-scale hydrologic modeling

    Science.gov (United States)

    Perez Fodich, A.; Walter, M. T.; Derry, L. A.

    2016-12-01

    The interaction of rocks with rainwater generates physical and chemical changes, which ultimately culminates in soil development. The addition of catalyzers such as plants, atmospheric gases and hydrological properties will result in more intense and/or faster weathering transformations. The intensity of weathering across the Island of Hawaii is strongly correlated with exposure age and time-integrated precipitation. Intense weathering has resulted from interaction between a thermodynamically unstable lithology, high water/rock ratios, atmospheric gases (O2, CO2) and biota as an organic acid and CO2 producer. To further investigate the role of different weathering agents we have developed 1-D reactive transport models (RTM) to understand mineralogical and fluid chemistry changes in the initially basaltic porous media. The initial meso-scale heterogeneity of porosity makes it difficult for RTMs to capture changes in runoff/groundwater partitioning. Therefore, hydraulic properties (hydraulic conductivity and aquifer depth) are modeled as a watershed parameter appropriate for this system where sub-surface hydraulic data is scarce(1). Initial results agree with field data in a broad sense: different rainfall regimes and timescales show depletion of mobile cations, increasingly low pH, congruent dissolution of olivine and pyroxene, incongruent dissolution of plagioclase and basaltic glass, precipitation of non-crystalline allophane and ferrihydrite, and porosity changes due to dissolution and precipitation of minerals; ultimately Al and Fe are also exported from the system. RTM is used to examine the roles of unsaturation in the soil profile, ligand promoted dissolution of Al- and Fe-bearing phases, and Fe-oxide precipitation at the outcrop scale. Also, we aim to test the use of recession flow analysis to model watershed-scale hydrological properties to extrapolate changes in the runoff/groundwater partitioning. The coupling between weathering processes and hydrologic

  3. Improving Weather Research and Forecasting Model Initial Conditions via Surface Pressure Analysis

    Science.gov (United States)

    2015-09-01

    Obsgrid) that creates input data for the Advanced Research version of the Weather Research and Forecasting model (WRF-ARW) is modified to perform a...Configuration  The Advanced Research version of the Weather Research and Forecasting model (WRF-ARW) V3.6.1 (Skamarock et al. 2008) is applied with 56 vertical...those with more benign weather. On 7 February a trough moved onshore and led to widespread precipitation in the region . More quiescent weather was in

  4. Chemical Weathering in the San Gabriel Mountains of California: The influence of erosion rates, soil depth, and transport processes on soil chemical losses (Invited)

    Science.gov (United States)

    Dixon, J. L.; Hartshorn, A. S.; Heimsath, A. M.; Dibiase, R. A.; Whipple, K. X.

    2010-12-01

    What controls the chemical weathering of soils in actively eroding landscapes? In this study, we explore the tectonic signature on soil weathering in the San Gabriel Mountains (SGM) of California, where propagating waves of incision triggered by increasing rock uplift have resulted in distinctly different hillslope morphologies and erosion rates across the range. We quantify downslope patterns of soil weathering across this landscape using sites that bracket low-gradient hillslopes of the stable upland plateau and hillslopes near the margins of the incising landscape. We use elemental mass balances in rock and soil to index the weathered extent of soils, and couple these extents with previously measured 10Be-derived soil production rates to calculate rates of soil weathering and erosion. Across all sites, Tau-Si—the fractional loss or gain of Si from parent material—averages -0.32±0.04, and the weathered extent of soils generally increases with increasing distance from the hillcrest. However, weathering intensities decrease as hillslope gradients steepen beyond 30°. Chemical weathering extents on slopes controlling mineral supply and residence time. These patterns are consistent with previously published predictive models for denudation-weathering relationships based on mineral weathering kinetics. Variable weathering extents in soils indicate that soil weathering in the SGM is largely kinetically limited. This work provides a field-based quantification of the complex relationship between soil erosion and chemical weathering, and together our data suggest that tectonic forcing strongly influences soil weathering rates and extents through its control on erosion rates, transport processes and soil thickness.

  5. Columbus AFB, Columbus, Mississippi. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    Science.gov (United States)

    1975-11-05

    Weather Service (MAC) 13. NU S .AES- Scott AFB IL 62225 , 468 p. 14 MONITORING AGENCY NAME & ADDRESS(II dillerIl I,nm Controfling Oihce) IS SECURIT /Y.CL...64 DATA lPRk;CFS3 ’ 4G WvlnC4 .- , /- ,rSURFACE WINDS 4 ,! W Ai) h .tI-RPVI> : , ,PERCENTAGE FREQUENCY OF WIND it DIRECTION AND SPEED (FROM HOURLY...69., 69. 6, 9, 2:k 350 lu.222 27) 26 7o.9 7 . ? .2 1.2~ 74.? P( Z~~ ~~ 300 4). 4g .7 66. 3 6 8 . 6 6 9 . 9 7 0 . 2 7 ( . 70 1,, ’ , 71.I ?1 71., l

  6. Earth surface erosion and weathering from the 10Be (meteoric)/9Be ratio

    Science.gov (United States)

    von Blanckenburg, F.; Bouchez, J.; Wittmann, H.; Dannhaus, N.

    2012-12-01

    A perfect clock of the stability of the Earth surface is one that combines a first isotope the flux of which depends on the release rate during erosion, and a second isotope produced at constant rate. The ratio of the meteoric cosmogenic nuclide 10Be to stable 9Be is such a system. We provide a quantitative framework for its use. In a weathering zone some of the 9Be, present typically in 2.5ppm concentrations in silicate minerals, is released and partitioned between a reactive phase (adsorbed to clay and hydroxide surfaces, given the high partition coefficients at intermediate pH), and into the dissolved phase. The combined mass flux of both phases is defined by the soil formation rate and a mineral dissolution rate - and is hence proportional to the chemical weathering rate and the denudation rate. At the same time, the surface of the weathering zone is continuously exposed to fallout of meteoric 10Be. This 10Be percolates into the weathering zone where it mixes with dissolved 9Be. Both isotopes may exchange with the adsorbed Be, given that equilibration rate of Be is fast relative to soil residence times. Hence a 10Be/9Be(reactive) ratio results in soils from which the total denudation rate can be calculated. A prerequisite is that the flux of meteoric 10Be is known from field experiments or from global production models [1], that the 9Be concentration in bedrock (mostly 2.5ppm) is known [2], and that the reactive Be can be chemically extracted from soil or sediment [3]. In rivers, when reactive Be and dissolved Be equilibrate, a catchment-wide denudation rate can be determined from both sediment and a sample of filtered river water, where the sediment 10Be/9Be ratio is independent of grain size. We have tested this approach in sediment-bound Be and dissolved Be in water of the Amazon and Orinoco basin. The reactive Be was extracted from sediment by combined hydroxylamine and HCl leaches [2]. In the Amazon trunk stream, the Orinoco, Apure, and La Tigra river 10Be

  7. Lagrangian Transport Through Surfaces in Volume-Preserving Flows

    CERN Document Server

    Karrasch, Daniel

    2015-01-01

    Advective transport of scalar quantities through surfaces is of fundamental importance in many scientific applications. From the Eulerian perspective of the surface it can be quantified by the well-known integral of the flux density. The recent development of highly accurate semi-Lagrangian methods for solving scalar conservation laws and of Lagrangian approaches to coherent structures in turbulent (geophysical) fluid flows necessitate a new approach to transport from the (Lagrangian) material perspective. We present a Lagrangian framework for calculating transport of conserved quantities through a given surface in $n$-dimensional, fully aperiodic, volume-preserving flows. Our approach does not involve any dynamical assumptions on the surface or its boundary.

  8. Sensor performance and weather effects modeling for intelligent transportation systems (ITS) applications

    Science.gov (United States)

    Everson, Jeffrey H.; Kopala, Edward W.; Lazofson, Laurence E.; Choe, Howard C.; Pomerleau, Dean A.

    1995-01-01

    Optical sensors are used for several ITS applications, including lateral control of vehicles, traffic sign recognition, car following, autonomous vehicle navigation, and obstacle detection. This paper treats the performance assessment of a sensor/image processor used as part of an on-board countermeasure system to prevent single vehicle roadway departure crashes. Sufficient image contrast between objects of interest and backgrounds is an essential factor influencing overall system performance. Contrast is determined by material properties affecting reflected/radiated intensities, as well as weather and visibility conditions. This paper discusses the modeling of these parameters and characterizes the contrast performance effects due to reduced visibility. The analysis process first involves generation of inherent road/off- road contrasts, followed by weather effects as a contrast modification. The sensor is modeled as a charge coupled device (CCD), with variable parameters. The results of the sensor/weather modeling are used to predict the performance on an in-vehicle warning system under various levels of adverse weather. Software employed in this effort was previously developed for the U.S. Air Force Wright Laboratory to determine target/background detection and recognition ranges for different sensor systems operating under various mission scenarios.

  9. Climate, Weather and Daily Mobility : Transport Mode Choices and Travel Experiences in the Randstad Holland

    NARCIS (Netherlands)

    Böcker, L.

    2014-01-01

    Intuitively, weather plays an important role in everyday mobility. How often do we not expose ourselves to cold, heat, sun, rain, snow or wind when we are travelling on foot or by bicycle; waiting at a bus stop; walking towards a parked car; or driving under slippery road conditions. Recently, weath

  10. 76 FR 50312 - Surface Transportation Environment and Planning Cooperative Research Program (STEP)

    Science.gov (United States)

    2011-08-12

    ... transportation safety planning strategies for surface transportation systems and improvements; (5) Improving... Federal Highway Administration Surface Transportation Environment and Planning Cooperative Research...-LU) established the Surface Transportation Environment and Planning Cooperative Research Program...

  11. Predicting Solar Cycle 25 using Surface Flux Transport Model

    Science.gov (United States)

    Imada, Shinsuke; Iijima, Haruhisa; Hotta, Hideyuki; Shiota, Daiko; Kusano, Kanya

    2017-08-01

    It is thought that the longer-term variations of the solar activity may affect the Earth’s climate. Therefore, predicting the next solar cycle is crucial for the forecast of the “solar-terrestrial environment”. To build prediction schemes for the next solar cycle is a key for the long-term space weather study. Recently, the relationship between polar magnetic field at the solar minimum and next solar activity is intensively discussed. Because we can determine the polar magnetic field at the solar minimum roughly 3 years before the next solar maximum, we may discuss the next solar cycle 3years before. Further, the longer term (~5 years) prediction might be achieved by estimating the polar magnetic field with the Surface Flux Transport (SFT) model. Now, we are developing a prediction scheme by SFT model as a part of the PSTEP (Project for Solar-Terrestrial Environment Prediction) and adapting to the Cycle 25 prediction. The predicted polar field strength of Cycle 24/25 minimum is several tens of percent smaller than Cycle 23/24 minimum. The result suggests that the amplitude of Cycle 25 is weaker than the current cycle. We also try to obtain the meridional flow, differential rotation, and turbulent diffusivity from recent modern observations (Hinode and Solar Dynamics Observatory). These parameters will be used in the SFT models to predict the polar magnetic fields strength at the solar minimum. In this presentation, we will explain the outline of our strategy to predict the next solar cycle and discuss the initial results for Cycle 25 prediction.

  12. Weathering on land and transport of chromium to the ocean in a subtropical region (Misiones, NW Argentina)

    DEFF Research Database (Denmark)

    Frei, Robert; Poiré, Daniel G.; Frei, Karin Margarita

    2014-01-01

    We have investigated the pathway of chromium from its mobilization on land and along its riverine transport in a subtropical region of South America (Misiones Province, Argentina), in an attempt to link Cr stable isotope compositions recently measured in seawater with signals prevailing in rivers.......4‰, balancing the negatively fractionated weathering products. The isotope composition and concentration of dissolved Cr in the ca. 1200 km long Paraná River from Misiones to its estuary and discharge area into the South Atlantic Ocean remains relatively constant with an average Cr concentration around 2.4 ppb...

  13. BET surface area distributions in polar stream sediments: Implications for silicate weathering in a cold-arid environment

    Science.gov (United States)

    Marra, Kristen R.; Elwood Madden, Megan E; Soreghan, Gerilyn S.; Hall, Brenda L

    2014-01-01

    BET surface area values are critical for quantifying the amount of potentially reactive sediments available for chemical weathering and ultimately, prediction of silicate weathering fluxes. BET surface area values of fine-grained (glacier surfaces, where dust is trapped and subsequently liberated during summer melting. Additionally, variations in stream discharge rate, which mobilizes sediment in pulses and influences water:rock ratios, the origin and nature of the underlying drift material, and the contribution of organic acids may play significant roles in the production and mobilization of high-surface area sediment. This study highlights the presence of sediments with high surface area in cold-based glacier systems, which influences models of chemical denudation rates and the impact of glacial systems on the global carbon cycle.

  14. Nonlinear Transport In Gases, Traps And Surfaces

    Science.gov (United States)

    Šuvakov, M.; Marjanovic, S.

    2010-07-01

    We will present our numerical study of three different charge transport processes and we will compare properties, specially the nonlinearity, of these processes. First process is electron transport in gases in swarm regime. We used well tested Monte Carlo techique to investigate kinetic phenomena such as negative diferencial conductivity (NDC) or negative apsolute mobility (NAM). We explain these phenomena analysing the spatial profiles of the swarm and collision events. In the second part we will apply the same technique on positron transport to obtain the same level of understanding of positron transport as has been achieved for electrons. The influence of positronium formation, non-conservative process, is much larger than any comparable effects in electron transport due to attachment and/or ionisation. As a result several new phenomena have been observed, such as NDC for the bulk drift velocity. Additionaly, the same Monte Carlo technique is used for modeling and optimisation of Surko like positron traps in different geometries and field configurations. Third process we studied is the charge transport under voltage bias via single-electron tunnelings through the junctions between metallic particles on nanoparticle films. We show how the regular nanoparticle array and topologically inhomogeneous nanonetworks affect the charge transport. We find long-range correlations in the time series of charge fluctuation at individual nanoparticles and of flow along the junctions within the network. These correlations explain the occurrence of a large non-linearity in the simulated and experimentally measured current-voltage characteristics and non-Gaussian fluctuations of the current at the electrode.

  15. Oil droplet self-transportation on oleophobic surfaces

    Science.gov (United States)

    Li, Juan; Qin, Qi Hang; Shah, Ali; Ras, Robin H. A.; Tian, Xuelin; Jokinen, Ville

    2016-01-01

    Directional liquid transportation is important for a variety of biological processes and technical applications. Although surface engineering through asymmetric chemical modification or geometrical patterning facilitates effective liquid manipulation and enables water droplet self-transportation on synthetic surfaces, self-transportation of oil droplets poses a major challenge because of their low surface tension. We report oil droplet self-transportation on oleophobic surfaces that are microtextured with radial arrays of undercut stripes. More significantly, we observe three modes of oil motion on various sample surfaces, namely, inward transportation, pinned, and outward spreading, which can be switched by the structure parameters, including stripe intersection angle and width. Accompanying theoretical modeling provides an in-depth mechanistic understanding of the structure–droplet motion relationship. Finally, we reveal how to optimize the texture parameters to maximize oil droplet self-transportation capability and demonstrate spontaneous droplet movement for liquids down to a surface tension of 22.4 mN/m. The surfaces presented here open up new avenues for power-free liquid transportation and oil contamination self-removal applications in various analytical and fluidic devices. PMID:27386574

  16. Comparison of surface water chemistry and weathering effects of two lake basins in the Changtang Nature Reserve, China.

    Science.gov (United States)

    Wang, Rui; Liu, Zhaofei; Jiang, Liguang; Yao, Zhijun; Wang, Junbo; Ju, Jianting

    2016-03-01

    The geochemistry of natural waters in the Changtang Nature Reserve, northern Tibet, can help us understand the geology of catchments, and provide additional insight in surface processes that influence water chemistry such as rock weathering on the Qinghai-Tibet Plateau. However, severe natural conditions are responsible for a lack of scientific data for this area. This study represents the first investigation of the chemical composition of surface waters and weathering effects in two lake basins in the reserve (Lake Dogaicoring Qiangco and Lake Longwei Co). The results indicate that total dissolved solids (TDS) in the two lakes are significantly higher than in other gauged lakes on the Qinghai-Tibet Plateau, reaching 20-40g/L, and that TDS of the tectonic lake (Lake Dogaicoring Qiangco) is significantly higher than that of the barrier lake (Lake Longwei Co). Na(+) and Cl(-) are the dominant ions in the lake waters as well as in the glacier-fed lake inflows, with chemical compositions mainly affected by halite weathering. In contrast, ion contents of inflowing rivers fed by nearby runoff are lower and concentrations of dominant ions are not significant. Evaporite, silicate, and carbonate weathering has relatively equal effects on these rivers. Due to their limited scope, small streams near the lakes are less affected by carbonate than by silicate weathering.

  17. Modeling Uranium Transport in Koongarra, Australia: The Effect of a Moving Weathering Zone

    OpenAIRE

    2001-01-01

    Natural analogues are an important source of long-term data and may be viewed as naturally occurring experiments that often include processes, phenomena, and scenarios that are important to nuclear waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region of Australia is one of the best-studied natural analogue sites. The deposit has been subjected to chemical weathering over several million years, during which many climatological, hydrological, an...

  18. Labrador Sea surface temperature control on the summer weather in the Eastern Europe

    Science.gov (United States)

    Gnatiuk, Natalia; Vihma, Timo; Bobylev, Leonid

    2016-04-01

    Many studies have addressed the linkages between the Arctic Amplification and mid-latitude weather patterns. Most of them have focused on the effects of changes in sea ice, terrestrial snow or open ocean SST on the air temperature in selected mid-latitude areas. However, when analysing such potential linkages, one should be aware that from the point of view of the atmosphere it is almost the same whether the thermal forcing originates from the sea ice melt, snowmelt, or changes in SST. Most important is to quantify how the atmosphere responds to anomalies in the surface temperature and then affects weather patterns in remote areas. For this purpose, we studied the hemispheric-scale relationships between anomalies in the Northern Hemisphere Earth surface temperature (Ts) and 2-m air temperature (T2m) in mid-latitudes (Central and Eastern Europe). Using regression analyses based on the ERA-Interim reanalysis data, we assessed the said temperature relationships with focus on the lagged monthly and inter-seasonal linkages. Technically we divided the Northern Hemisphere in equal areas with a size of 15x10 degrees and calculated correlation coefficients for the monthly mean temperatures between all defined regions from one side and the Central/East European study regions from another side over the period 1979-2014. Using this approach, we found that the strongest links in the considered kind of relationships take place between spring sea surface temperature in the Labrador Sea and summer air (T2m) temperature in the Eastern Europe. In order to confirm the correlation results obtained, to identify thermal forcing factors and to assess their relative importance, we analysed the multiyear averages and anomalies of various meteorological parameters for 10 coldest and 10 warmest springs and summers in the period 1979-2014: surface pressure, total precipitation, sea-ice and total cloud cover, wind components, surface solar radiation downwards, surface heat fluxes and air

  19. Soil, snow, weather, and sub-surface storage data from a mountain catchment in the rain-snow transition zone

    Science.gov (United States)

    A comprehensive hydroclimatic data set is presented for the 2011 water year to improve understanding of hydrologic processes in the rain-snow transition zone. Catchment soil depths and surface texture from 57 points are presented along with soil moisture, snow cover, weather data, and associated hy...

  20. Weathering and transport of chromium and nickel from serpentinite in the Coast Range ophiolite to the Sacramento Valley, California, USA

    Science.gov (United States)

    Morrison, Jean M.; Goldhaber, Martin B.; Mills, Christopher T.; Breit, George N.; Hooper, Robert L.; Holloway, JoAnn M.; Diehl, Sharon F.; Ranville, James F.

    2015-01-01

    A soil geochemical study in northern California was done to investigate the role that weathering and transport play in the regional distribution and mobility of geogenic Cr and Ni, which are both potentially toxic and carcinogenic. These elements are enriched in ultramafic rocks (primarily serpentinite) and the soils derived from them (1700–10,000 mg Cr per kg soil and 1300–3900 mg Ni per kg soil) in the Coast Range ophiolite. Chromium and Ni have been transported eastward from the Coast Range into the western Sacramento Valley and as a result, valley soil is enriched in Cr (80–1420 mg kg−1) and Ni (65–224 mg kg−1) compared to median values of U.S. soils of 50 and 15 mg kg−1, respectively. Nickel in ultramafic source rocks and soils is present in serpentine minerals (lizardite, antigorite, and chrysotile) and is more easily weathered compared to Cr, which primarily resides in highly refractory chromite ([Mg,Fe2+][Cr3+,Al,Fe3+]2O4). Although the majority of Cr and Ni in soils are in refractory chromite and serpentine minerals, the etching and dissolution of these minerals, presence of Cr- and Ni-enriched clay minerals and development of nanocrystalline Fe (hydr)oxides is evidence that a significant fractions of these elements have been transferred to potentially more labile phases.

  1. The Themis-Beagle families: Investigation of space-weathering processes on primitive surfaces

    Science.gov (United States)

    Fornasier, S.; Perna, D.; Lantz, C.; Barucci, M.

    2014-07-01

    In the past 20 years, enormous progress has been reached in the study of space-weathering (SW) effects on silicates and silicate asteroids. The so-called ordinary chondrite paradox, that is, lack of asteroids similar to the ordinary chondrites, which represent 80 % of meteorite falls, has been solved. These meteorites are now clearly related to S-type asteroids, as proved also by the direct measurements of the NEAR and HAYABUSA missions on the near-Earth asteroids Eros and Itokawa. Spectral differences between S-type asteroids and ordinary chondrites are caused by space-weathering effects, which produce a darkening in the albedo, a reddening of the spectra, and diminish the silicate absorption bands on the asteroids surfaces, exposed to cosmic radiation and solar wind. On the other hand, our understanding of space-weathering effects on primitive asteroids is still poor. Only few laboratory experiments have been devoted to the investigation of SW effects on dark carbonaceous chondrites and on complex organic materials. Irradiation of transparent organic materials produces firstly redder and darker materials that upon further processing turn flatter-bluish and darker (Kanuchova et al. 2012; Moroz et al. 2004). The Themis family is a natural laboratory to study primitive asteroids and space-weathering effects. The Themis family is located between 3.05 and 3.24 au, beyond the snow line, and it is composed of primitive asteroids. Themis is one of the most statistically reliable families in the asteroid belt. First discovered by Hirayama (1918), it has been identified as a family in all subsequent works, and it has 550 members as determined by Zappalà et al. (1995) and more than 4000 as determined by Nesvorny et al. (2010). The family formed probably about 2.3 Gyr ago as a result of a large-scale catastrophic disruption event of a parent asteroid 400 km in diameter colliding with a 190-km projectile (Marzari et al. 1995). Several Themis family members show absorption

  2. Effect of Photostablizers on Surface Color and Mechanical Property of Wood-flour/HDPE Composites after Weathering

    Institute of Scientific and Technical Information of China (English)

    XUE Ping; JIA Mingyin; WANG Kejian; DING Yun; WANG Linna

    2012-01-01

    The effects of photostabilizers of ultraviolet absorbers (UVA),hindered amine light stabilizer (HALS) and pigment on surface color change and mechanical properties of weathered wood-flour/polyethylene (HDPE) composites were investigated.After being added UVA with high UV absorbance,the WPC exhibites better ability to resist color fading and mechanical property loss.High molecular weight HALS is found to be the most effective in controlling long term fading and yellowing changes.Pigments cover the composites for remaining the original color after weathering regardless of less contribution to mechanical property.Addition of photostabilizer and pigment together show great synergism in decreasing color fading and flexural property loss.

  3. Near-Real Time Satellite-Retrieved Cloud and Surface Properties for Weather and Aviation Safety Applications

    Science.gov (United States)

    Minnis, Patrick; Smith, William L., Jr.; Bedka, Kristopher M.; Nguyen, Louis; Palikonda, Rabindra; Hong, Gang; Trepte, Qing Z.; Chee, Thad; Scarino, Benjamin; Spangenberg, Douglas A.; Sun-Mack, Szedung; Fleeger, Cecilia; Ayers, J. Kirk; Chang, Fu-Lung; Heck, Patrick M.

    2014-01-01

    Cloud properties determined from satellite imager radiances provide a valuable source of information for nowcasting and weather forecasting. In recent years, it has been shown that assimilation of cloud top temperature, optical depth, and total water path can increase the accuracies of weather analyses and forecasts. Aircraft icing conditions can be accurately diagnosed in near-­-real time (NRT) retrievals of cloud effective particle size, phase, and water path, providing valuable data for pilots. NRT retrievals of surface skin temperature can also be assimilated in numerical weather prediction models to provide more accurate representations of solar heating and longwave cooling at the surface, where convective initiation. These and other applications are being exploited more frequently as the value of NRT cloud data become recognized. At NASA Langley, cloud properties and surface skin temperature are being retrieved in near-­-real time globally from both geostationary (GEO) and low-­-earth orbiting (LEO) satellite imagers for weather model assimilation and nowcasting for hazards such as aircraft icing. Cloud data from GEO satellites over North America are disseminated through NCEP, while those data and global LEO and GEO retrievals are disseminated from a Langley website. This paper presents an overview of the various available datasets, provides examples of their application, and discusses the use of the various datasets downstream. Future challenges and areas of improvement are also presented.

  4. Comparison of alternative concepts for lunar surface transportation

    Science.gov (United States)

    Apel, Uwe

    The lunar surface transportation system is a key element in lunar development. The decision which means of conveyance should be preferred depends on a lot of influencing factors such as transportation requirements, physical boundary conditions and economics. Starting with a systematic approach to define and structure the problem, a model to compare alternative transportation systems has been built. From the pool of possible means of conveyance, chemical rockets, electric cars, maglev-trains and mass-drivers have been chosen as candidates for investigation. With these candidates five different surface transportation systems were defined. For a reference lunar development scenario the systems were compared on the basis of a cost-to-benefit ratio. Preliminary results indicate that under the assumption that LH2 could be produced on lunar surface, LOX/LH2 propulsed "Hoppers" seem very attractive up to medium transportation demands. For large amounts of bulk cargo, mass driver transportation seems to have advantages, and electric cars should be used for all transportation tasks if the transportation demand is high. Maglev-trains seem to be competitive only for very large transportation demand and long life cycles.

  5. Weathering performance of surface of thermally modified wood finished with nanoparticles-modified waterborne polyacrylate coatings

    Science.gov (United States)

    Miklečić, Josip; Turkulin, Hrvoje; Jirouš-Rajković, Vlatka

    2017-06-01

    In this research the samples of thermally modified (TMT) beech wood samples, finished with waterborne polyacrylate clear coatings modified with nano-sized ZnO and TiO2-rutil were naturally and artificially exposed to weathering conditions. To extend the lifetime of wood and maintain its natural look, the research and development of clear coatings with minimal use of harmful chemicals has become very important. Therefore nano-sized inorganic UV absorbers are increasingly used to enhance the durability of the coating and wood substrate, still retaining the transparency of the coating. During exposure the visual inspection was performed, further the changes of colour, gloss and adhesion were recorded. Interaction of the film with the thermally modified substrate surface were studied. Results showed that the addition of TiO2-rutil and ZnO nanoparticles to the waterborne polyacrylate coating improved the colour stability of thermally modified beech-wood. However, nano-sized ZnO increased the cracking and peeling, and caused the loss in adhesion strength of the film on thermally modified beech wood.

  6. Age and weathering rate of sediments in small catchments: the role of hillslope erosion

    Science.gov (United States)

    Dosseto, A.; Buss, H. L.; Chabaux, F.

    2014-12-01

    Erosion is intimately linked to chemical weathering, however we lack quantitative constraints on how erosion processes impact mineral weathering rates. Here we use the uranium-series isotope composition of river-borne material in small catchments of Puerto Rico and southeastern Australia to study the effect of contrasting erosion regimes on weathering. The U-series isotope composition of stream sediments was modelled to infer a weathering age, i.e. the average time elapsed since the sediment's minerals have started weathering. In southeastern Australia, the weathering age of stream sediments ranges between 346 ± 12 kyr and 1.78 ± 0.16 Myr, similar to values inferred from weathering profiles in the same catchment. Old weathering ages likely reflect the shallow origin of sediments mobilised via near-surface soil transport, the main mechanism of erosion in this catchment. Contrastingly, in Puerto Rico weathering ages are much younger, ranging from 5.1 ± 0.1 to 19.4 ± 0.4 kyr, reflecting that sediments are derived from less weathered, deeper saprolite, mobilised by landslides. Weathering ages of stream sediments are used to infer catchment-wide, mineral-specific weathering rates that are one to two orders of magnitude faster for Puerto Rico than for southeastern Australia. Thus, the type of erosion (near-surface soil transport vs. landslide) also affects the weathering rate of river sediments, because their weathering ages determine the potential for further weathering during sediment transport and storage in alluvial plains.

  7. Transport properties of interfacial Si-rich layers formed on silicate minerals during weathering: Implications for environmental concerns

    Science.gov (United States)

    Daval, Damien; Rémusat, Laurent; Bernard, Sylvain; Wild, Bastien; Micha, Jean-Sébastien; Rieutord, François; Fernandez-Martinez, Alejandro

    2015-04-01

    The dissolution of silicate minerals is of primary importance for various processes ranging from chemical weathering to CO2 sequestration. Whether it determines the rates of soil formation, CO2 uptake and its impact on climate change, channeling caused by hydrothermal circulation in reservoirs of geothermal power plants, durability of radioactive waste confinement glasses or geological sequestration of CO2, the same strategy is commonly applied for determining the long term evolution of fluid-rock interactions. This strategy relies on a bottom-up approach, where the kinetic rate laws governing silicate mineral dissolution are determined from laboratory experiments. However, a long-standing problem regarding this approach stems from the observation that laboratory-derived dissolution rates overestimate their field counterparts by orders of magnitude, casting doubt on the accuracy and relevance of predictions based on reactive-transport simulations. Recently [1], it has been suggested that taking into account the formation of amorphous Si-rich surface layers (ASSL) as a consequence of mineral dissolution may contribute to decrease the large gap existing between laboratory and natural rates. Our ongoing study is aimed at deciphering the extent to which ASSL may represent a protective entity which affects the dissolution rate of the underlying minerals, both physically (passivation) and chemically (by promoting the formation of a local chemical medium which significantly differs from that of the bulk solution). Our strategy relies on the nm-scale measurement of the physicochemical properties (diffusivity, thickness and density) of ASSL formed on cleavages of a model mineral (wollastonite) and their evolution as a function of reaction progress. Our preliminary results indicate that the diffusivity of nm-thick ASSL formed on wollastonite surface is ~1,000,000 times smaller than that reported for an aqueous medium, as estimated from the monitoring of the progression of a

  8. Urban Mobility and Economic Shock: How Bangkok’s Transportation System Weathered the 1997 Financial Crisis

    OpenAIRE

    Leipziger, David

    2015-01-01

    Bangkok is a rising global city, home to nearly 20 million people and notorious traffic congestion. Constrained mobility and accessibility have long underscored the centrality of transportation issues to managing growth. Historically, the preponderance of Bangkok’s transportation network interventions have expanded road capacity to alleviate traffic; however, major investments in the city’s mass transit network began in the late 1980’s and early 1990’s. This was also a time of massive economi...

  9. Vertical Transport of Subwavelength Localized Surface Electromagnetic Modes

    CERN Document Server

    Gao, Fei; Zhang, Youming; Shi, Xihang; Yang, Zhaoju; Zhang, Baile

    2015-01-01

    Transport of subwavelength electromagnetic (EM) energy has been achieved through near-field coupling of highly confined surface EM modes supported by plasmonic nanoparticles, in a configuration usually staying on a two-dimensional (2D) substrate. Vertical transport of similar modes along the third dimension, on the other hand, can bring more flexibility in designs of functional photonic devices, but this phenomenon has not been observed in reality. In this paper, designer (or spoof) surface plasmon resonators (plasmonic meta-atoms) are stacked in the direction vertical to their individual planes in demonstrating vertical transport of subwavelength localized surface EM modes. Dispersion relation of this vertical transport is determined from coupled mode theory and is verified with near-field transmission spectrum and field mapping with a microwave near-field scanning stage. This work extends the near-field coupled resonator optical waveguide (CROW) theory into the vertical direction, and may find applications ...

  10. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  11. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  12. Implementation of Globally Simulated Dust within a Physical Sea Surface Temperature Retrievals for Numerical Weather Prediction

    Science.gov (United States)

    Oyola, M. I.; Nalli, N. R.; Lu, C. H.; Joseph, E.; Morris, V. R.; Campbell, J. R.

    2016-12-01

    Aerosols are not the only source of error in sea surface temperature (SST) retrievals; however, it is nontrivial problem that requires attention. Simulation and validation of aerosol in radiative transfer models (RTM) is considered extremely challenging, especially in the infrared (IR); this is because brightness temperatures (BTs) retrievals -which are converted into SSTs- are highly influenced by changes in atmospheric composition. Tropospheric aerosols seem to have a persistent impact that may result in negative SST biases of 1K or more. Several questions arise around this topic, but most importantly: is it even possible to simulate aerosols using a RTM for a SST retrieval application? If so, what are the implications? This works presents the results for the first study to ever attempt to analyze the full potential and limitations of incorporating aerosols within a truly physical SST retrieval for operational weather forecasting purposes. This is accomplished through the application of a satellite sea surface temperature (SST) physical retrieval for split-window and hyperspectral infrared (IR) sensors that allows a better representation of the atmospheric state under aerosol-laden conditions. The new algorithm includes 1) accurate specification of the emissivity that characterizes the surface leaving radiance and 2) transmittance and physical characterization of the atmosphere by using the Community Radiative Transfer Model (CRTM). This project includes application of the NEMS-Global Forecasting System Aerosol Component (NGAC) fields, which corresponds to the first global interactive atmosphere-aerosol forecast system ever implemented at NOAA's National Center for Environmental Prediction (NCEP). SST outputs are validated against a bulk and a parameterized SST derived from operational products and partly against observed measurements from the eastern Atlantic Ocean, which is dominated by Saharan dust throughout most of the year and that is also a genesis region

  13. All-Weather Sounding of Moisture and Temperature From Microwave Sensors Using a Coupled Surface/Atmosphere Inversion Algorithm

    Science.gov (United States)

    Boukabara, S. A.; Garrett, K.

    2014-12-01

    A one-dimensional variational retrieval system has been developed, capable of producing temperature and water vapor profiles in clear, cloudy and precipitating conditions. The algorithm, known as the Microwave Integrated Retrieval System (MiRS), is currently running operationally at the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite Data and Information Service (NESDIS), and is applied to a variety of data from the AMSU-A/MHS sensors on board the NOAA-18, NOAA-19, and MetOp-A/B polar satellite platforms, as well as SSMI/S on board both DMSP F-16 and F18, and from the NPP ATMS sensor. MiRS inverts microwave brightness temperatures into atmospheric temperature and water vapor profiles, along with hydrometeors and surface parameters, simultaneously. This atmosphere/surface coupled inversion allows for more accurate retrievals in the lower tropospheric layers by accounting for the surface emissivity impact on the measurements. It also allows the inversion of the soundings in all-weather conditions thanks to the incorporation of the hydrometeors parameters in the inverted state vector as well as to the inclusion of the emissivity in the same state vector, which is accounted for dynamically for the highly variable surface conditions found under precipitating atmospheres. The inversion is constrained in precipitating conditions by the inclusion of covariances for hydrometeors, to take advantage of the natural correlations that exist between temperature and water vapor with liquid and ice cloud along with rain water. In this study, we present a full assessment of temperature and water vapor retrieval performances in all-weather conditions and over all surface types (ocean, sea-ice, land, and snow) using matchups with radiosonde as well as Numerical Weather Prediction and other satellite retrieval algorithms as references. An emphasis is placed on retrievals in cloudy and precipitating atmospheres, including extreme weather events

  14. Studying Polymer Transport on Soft and Hard Surfaces

    Science.gov (United States)

    Kumar, Sanat

    2007-03-01

    We have employed experiments and simulations to understand the factors controlling the transport of polymers on surfaces. From an experimental viewpoint we have focused on the transport of DNA (single stranded) on lipid bilayers. We show that this behavior is slaved to the mobility of the lipids. More surprisingly, it appears that the transport of molecules adsorbed on surfaces follows the same dependence on lipid mobility as for molecules incorporated into the lipid layer. The ability to control this surface diffusion through the introduction of posts or varying the strength of adsorption (by the use of an AC field normal to the surfaces) will also be studied. Theoretically we have used molecular dynamics simulations of a polymer chain of length N dissolved in explicit solvent and adsorbed as a pancake at the solid-liquid interface to discriminate between respective influences on surface diffusion of hydrodynamics and adsorption energetics. Only for analytically-smooth surfaces do we observe a strong influence of hydrodynamics; the polymer lateral diffusion constant, D, scales as D 1/N^3/4, more weakly than for implicit solvent. For atomistic surface corrugation with uniform surface chemical makeup, D 1/N instead. This suggests that while we can understand the results for diffusion on lipid surfaces, more recent experimental observations of stronger N dependence for diffusion on hard solid surfaces originate not in hydrodynamic interactions but in spatially patchy energetic interactions.

  15. Problems at the Leading Edge of Space Weathering as Revealed by TEM Combined with Surface Science Techniques

    Science.gov (United States)

    Christoffersen, R.; Dukes, C. A.; Keller, L. P.; Rahman, Z.; Baragiola, R. A.

    2015-01-01

    Both transmission electron micros-copy (TEM) and surface analysis techniques such as X-ray photoelectron spectroscopy (XPS) were instrumen-tal in making the first characterizations of material generated by space weathering in lunar samples [1,2]. Without them, the nature of nanophase metallic Fe (npFe0) correlated with the surface of lunar regolith grains would have taken much longer to become rec-ognized and understood. Our groups at JSC and UVa have been using both techniques in a cross-correlated way to investigate how the solar wind contributes to space weathering [e.g., 3]. These efforts have identified a number of ongoing problems and knowledge gaps. Key insights made by UVa group leader Raul Barag-iola during this work are gratefully remembered.

  16. Weather induced effects on extensive air showers observed with the surface detector of the Pierre Auger Observatory

    CERN Document Server

    Bleve, Carla

    2007-01-01

    The rate of events measured with the surface detector of the Pierre Auger Observatory is found to be modulated by the weather conditions. This effect is due to the increasing amount of matter traversed by the shower as the ground pressure increases and to the inverse proportionality of the Moliere radius to the air density near ground. Air-shower simulations with different realistic profiles of the atmosphere support this interpretation of the observed effects.

  17. Modeling land-surface processes and land-atmosphere interactions in the community weather and regional climate WRF model (Invited)

    Science.gov (United States)

    Chen, F.; Barlage, M. J.

    2013-12-01

    The Weather Research and Forecasting (WRF) model has been widely used with high-resolution configuration in the weather and regional climate communities, and hence demands its land-surface models to treat not only fast-response processes, such as plant evapotranspiration that are important for numerical weather prediction but also slow-evolving processes such as snow hydrology and interactions between surface soil water and deep aquifer. Correctly representing urbanization, which has been traditionally ignored in coarse-resolution modeling, is critical for applying WRF to air quality and public health research. To meet these demands, numerous efforts have been undertaken to improve land-surface models (LSM) in WRF, including the recent implementation of the Noah-MP (Noah Multiple-Physics). Noah-MP uses multiple options for key sub-grid land-atmosphere interaction processes (Niu et al., 2011; Yang et al., 2011), and contains a separate vegetation canopy representing within- and under-canopy radiation and turbulent processes, a multilayer physically-based snow model, and a photosynthesis canopy resistance parameterization with a dynamic vegetation model. This paper will focus on the interactions between fast and slow land processes through: 1) a benchmarking of the Noah-MP performance, in comparison to five widely-used land-surface models, in simulating and diagnosing snow evolution for complex terrain forested regions, and 2) the effects of interactions between shallow and deep aquifers on regional weather and climate. Moreover, we will provide an overview of recent improvements of the integrated WRF-Urban modeling system, especially its hydrological enhancements that takes into account the effects of lawn irrigation, urban oasis, evaporation from pavements, anthropogenic moisture sources, and a green-roof parameterization.

  18. Sea surface temperature and Ekman transport in the Persian Gulf

    Directory of Open Access Journals (Sweden)

    E. H.

    2002-12-01

    Full Text Available   The wind drift motion of the water which is produced by the stress of the wind exerted upon the surface of the ocean is described by Ekmans theory (1905. Using the mean monthly values for the wind stress and SST, seasonal Ekman transport for the Persian Gulf was computed and contoured. The geostrophic winds have combined with the SST to estimate the effect of cooling due to Ekman transport of colder northern waters and inflow from the Oman Sea. The monthly SST mainly obtained from the 10 10 grided data of Levitus atlas and Hormuz Cruis Experiment for 1997.   Analyses show a NW to SE Ekman transport due to wind stress and significant interannual variability of SST on sea surface in the Persian Gulf. The seasonal variation of SST shows a continental pattern due to severe interaction between the land and sea. But these variations somehow moderates because of Ekman transport in Persian Gulf.

  19. Effect of wet-cold weather transportation conditions on thermoregulation and the development of accidental hypothermia in pullets under tropical conditions.

    Science.gov (United States)

    Minka, Ndazo S; Ayo, Joseph O

    2016-03-01

    The present study examines onboard thermal microclimatic conditions and thermoregulation of pullets exposed to accidental hypothermia during wet-cold weather transportation conditions, and the effect of rewarming on colonic temperature (CT) of the birds immediately after transportation. A total of 2200 pullets were transportation for 5 h in two separate vehicles during the nighttime. The last 3 h of the transportation period was characterized by heavy rainfall. During the precipitation period, each vehicle was covered one fourth way from the top-roof with a tarpaulin. The onboard thermal conditions inside the vehicles during transportation, which comprised ambient temperature and relative humidity were recorded, while humidity ratio and specific enthalpy were calculated. The CT of the birds was recorded before and after transportation. During transportation, onboard thermal heterogeneity was observed inside the vehicles with higher (p transported pullets under tropical conditions and a successful rewarming outcome. In conclusion, transportation of pullets during wet weather at onboard temperature of 18-20 °C induced hypothermia on birds located at the air inlets, which recovered fully after several hours of gradual rewarming.

  20. Topographic imprint on chemical weathering in deeply weathered soil-mantled landscapes (southern Brazil)

    Science.gov (United States)

    Vanacker, Veerle; Schoonejans, Jerome; Ameijeiras-Marino, Yolanda; Opfergelt, Sophie; Minella, Jean

    2017-04-01

    The regolith mantle is defined as the thin layer of unconsolidated material overlaying bedrock that contributes to shape the Earth's surface. The development of the regolith mantle in a landscape is the result of in-situ weathering, atmospheric input and downhill transport of weathering products. Bedrock weathering - the physical and chemical transformations of rock to soil - contributes to the vertical development of the regolith layer through downward propagation of the weathering front. Lateral transport of soil particles, aggregates and solutes by diffusive and concentrated particle and solute fluxes result in lateral redistribution of weathering products over the hillslope. In this study, we aim to expand the empirical basis on long-term soil evolution at the landscape scale through a detailed study of soil weathering in subtropical soils. Spatial variability in chemical mass fluxes and weathering intensity were studied along two toposequences with similar climate, lithology and vegetation but different slope morphology. This allowed us to isolate the topographic imprint on chemical weathering and soil development. The toposequences have convexo-concave slope morphology, and eight regolith profiles were analysed involving the flat upslope, steep midslope and flat toeslope part. Our data show a clear topographic imprint on soil development. Along hillslope, the chemical weathering intensity of the regolith profiles increases with distance from the crest. In contrast to the upslope positions, the soils in the basal concavities develop on in-situ and transported regolith. While the chemical weathering extent on the slope convexities (the upslope profiles) is similar for the steep and gentle toposequence, there is a clear difference in the rate of increase of the chemical weathering extent with distance from the crest. The increase of chemical weathering extent along hillslope is highest for the steep toposequence, suggesting that topography enhances soil particle

  1. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

    Science.gov (United States)

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-10-01

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

  2. Surface analysis and anti-graffiti behavior of a weathered polyurethane-based coating embedded with hydrophobic nano silica

    Science.gov (United States)

    Rabea, A. Mohammad; Mohseni, M.; Mirabedini, S. M.; Tabatabaei, M. Hashemi

    2012-03-01

    In this study, a permanent anti-graffiti polyurethane coating was prepared using concomitant loading of an OH-functional silicone modified polyacrylate additive ranging from 2 to 15 mol% and hydrophobic silica nanoparticles from 1 to 5 wt%. UV-visible spectroscopy, contact angle measurement and dynamic mechanical thermal analysis (DMTA) analysis were conducted on selected samples to study the weathering performance of samples containing various amounts of silica nanoparticles before and after accelerated weathering conditions. The results showed that higher amounts of additive had inferior effects on the anti-graffiti performance of the coating samples after exposure. However, silica nanoparticles could positively affect the anti-graffiti performance against ageing cycles. This improvement was attributed to lower degradation of samples containing silica nanoparticles and barrier property of nanoparticles against graffiti penetration. The presence of silica nanoparticles did not have any significant effect on the surface free energy of the samples prior and after ageing.

  3. Frost Monitoring and Forecasting Using MODIS Land Surface Temperature Data and a Numerical Weather Prediction Model Forecasts for Eastern Africa

    Science.gov (United States)

    Kabuchanga, Eric; Flores, Africa; Malaso, Susan; Mungai, John; Sakwa, Vincent; Shaka, Ayub; Limaye, Ashutosh

    2014-01-01

    Frost is a major challenge across Eastern Africa, severely impacting agricultural farms. Frost damages have wide ranging economic implications on tea and coffee farms, which represent a major economic sector. Early monitoring and forecasting will enable farmers to take preventive actions to minimize the losses. Although clearly important, timely information on when to protect crops from freezing is relatively limited. MODIS Land Surface Temperature (LST) data, derived from NASA's Terra and Aqua satellites, and 72-hr weather forecasts from the Kenya Meteorological Service's operational Weather Research Forecast model are enabling the Regional Center for Mapping of Resources for Development (RCMRD) and the Tea Research Foundation of Kenya to provide timely information to farmers in the region. This presentation will highlight an ongoing collaboration among the Kenya Meteorological Service, RCMRD, and the Tea Research Foundation of Kenya to identify frost events and provide farmers with potential frost forecasts in Eastern Africa.

  4. Surface hall effect and nonlocal transport in SmB₆: evidence for surface conduction.

    Science.gov (United States)

    Kim, D J; Thomas, S; Grant, T; Botimer, J; Fisk, Z; Xia, Jing

    2013-11-06

    A topological insulator (TI) is an unusual quantum state in which the insulating bulk is topologically distinct from vacuum, resulting in a unique metallic surface that is robust against time-reversal invariant perturbations. The surface transport, however, remains difficult to isolate from the bulk conduction in most existing TI crystals (particularly Bi₂Se₃, Bi₂Te₃ and Sb₂Te₃) due to impurity caused bulk conduction. We report in large crystals of topological Kondo insulator (TKI) candidate material SmB₆ the thickness-independent surface Hall effects and non-local transport, which persist after various surface perturbations. These results serve as proof that at low temperatures SmB₆ has a metallic surface that surrounds an insulating bulk, paving the way for transport studies of the surface state in this proposed TKI material.

  5. 75 FR 38605 - Surface Transportation Environment and Planning Cooperative Research Program (STEP)

    Science.gov (United States)

    2010-07-02

    ... research to address congestion reduction efforts; (4) Developing transportation safety planning strategies... Federal Highway Administration Surface Transportation Environment and Planning Cooperative Research...-LU) established the Surface Transportation Environment and Planning Cooperative Research Program...

  6. Directional transport of impinging capillary jet on wettability engineered surfaces

    Science.gov (United States)

    Ghosh, Aritra; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Impingement of capillary jet on a surface is important for applications like heat transfer, or for liquid manipulation in bio-microfluidic devices. Using wettability engineered surfaces, we demonstrate pump-less and directional transport of capillary jet on a flat surface. Spatial contrast of surface energy and a wedge-shape geometry of the wettability confined track on the substrate facilitate formation of instantaneous spherical bulges upon jet impingement; these bulges are further transported along the superhydrophilic tracks due to Laplace pressure gradient. Critical condition warranted for formation of liquid bulge along the varying width of the superhydrophilic track is calculated analytically and verified experimentally. The work throws light on novel fluid phenomena of unidirectional jet impingement on wettability confined surfaces and provides a platform for innovative liquid manipulation technique for further application. By varying the geometry and wettability contrast on the surface, one can achieve volume flow rates of ~ O(100 μL/sec) and directionally guided transport of the jet liquid, pumplessly at speeds of ~ O(10cm/sec).

  7. Modeling marine surface microplastic transport to assess optimal removal locations

    NARCIS (Netherlands)

    Sherman, Peter; Van Sebille, Erik

    2016-01-01

    Marine plastic pollution is an ever-increasing problem that demands immediate mitigation and reduction plans. Here, a model based on satellite-tracked buoy observations and scaled to a large data set of observations on microplastic from surface trawls was used to simulate the transport of plastics f

  8. Modeling marine surface microplastic transport to assess optimal removal locations

    NARCIS (Netherlands)

    Sherman, Peter; Van Sebille, Erik|info:eu-repo/dai/nl/304831921

    2016-01-01

    Marine plastic pollution is an ever-increasing problem that demands immediate mitigation and reduction plans. Here, a model based on satellite-tracked buoy observations and scaled to a large data set of observations on microplastic from surface trawls was used to simulate the transport of plastics

  9. Barents Sea heat – transport, storage and surface fluxes

    Directory of Open Access Journals (Sweden)

    Ø. Skagseth

    2009-07-01

    Full Text Available Sensitivity of the Barents Sea to variation in ocean heat transport and surface fluxes is explored using a 1-D column model. Mean monthly ocean transport and atmospheric forcing are synthesised and force model results that reproduce the observed winter convection and surface warming and freshening well. Model results are compared to existing estimates of the ocean to air heat fluxes and horizontally averaged profiles for the southern and northern Barents Sea. Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production. The northern Barents Sea, the major part of the area, receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss in the north, the balance is achieved by long wave loss removing most of the solar heating, and the model also suggests a positive sensible heat gain. During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. Despite large changes the Barents Sea heat loss remains robust, the temperature adjusts, and the yearly cycle remains. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport probably leads to a spreading of warm water further north.

  10. STM tip-mediated mass transport on Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.S.N. [College of Physical Science and Technology, Shenyang Normal University, Huanghe Street 253, Shenyang 110034 (China); Huang, R.Z., E-mail: renzhonghuang@synu.edu.cn [College of Physical Science and Technology, Shenyang Normal University, Huanghe Street 253, Shenyang 110034 (China); Gao, T.F. [College of Physical Science and Technology, Shenyang Normal University, Huanghe Street 253, Shenyang 110034 (China); Zhang, R.J. [School of Information Science and Engineering, Fudan University, Handan Road 220, Shanghai 200433 (China); Wang, Y.M. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016 (China)

    2015-02-01

    Highlights: • Tip-induced atomic motion of Co atoms embedded in the Cu (0 0 1) surface in the presence of vacancies. • Interlayer mass transport at the island edge is found to depend strongly on the tip height and the lateral distance from the tip. • The jumping and the Ehrlich–Schwoebel (E–S) diffusion barrier can be reduced by tip manipulation. - Abstract: Atomic-scale simulations are performed to study atomic motion on Cu surfaces to illustrate the effect of the scanning tunneling microscopy tip on mass transport (MT) in the surfaces and on top of the Co island in heteroepitaxial Co/Cu(0 0 1) and Co/Cu(1 1 1) systems. First we investigate tip-induced atomic motion of Co atoms embedded in the Cu(0 0 1) surface at zero bias voltage. With the help of the tip, the Co atom in the surface can freely diffuse toward its nearby vacancy site. So-called vacancy mechanism is used to interpret this phenomenon. Then tip-mediated atomic motion of Co adatoms on the Co islands supported by a Cu(1 1 1) surface is studied. It is revealed that the tip has a significant effect on the diffusion of adatoms on the islands and interlayer mass transport at the island edge. Interlayer mass transport at the island edge is found to depend strongly on the tip height and the lateral distance from the tip. By calculating the diffusion barriers, it is found that the jumping diffusion barrier on the island can be zero by the tip vertical manipulation while the Ehrlich–Schwoebel diffusion barrier at the island edge can be reduced by the tip lateral manipulation. Thus, the quality of thin films can be improved by controlling MT in and/or on the surface.

  11. Evaluating the Impacts of NASA/SPoRT Daily Greenness Vegetation Fraction on Land Surface Model and Numerical Weather Forecasts

    Science.gov (United States)

    Bell, Jordan R.; Case, Jonathan L.; LaFontaine, Frank J.; Kumar, Sujay V.

    2012-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center has developed a Greenness Vegetation Fraction (GVF) dataset, which is updated daily using swaths of Normalized Difference Vegetation Index data from the Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA EOS Aqua and Terra satellites. NASA SPoRT began generating daily real-time GVF composites at 1-km resolution over the Continental United States (CONUS) on 1 June 2010. The purpose of this study is to compare the National Centers for Environmental Prediction (NCEP) climatology GVF product (currently used in operational weather models) to the SPoRT-MODIS GVF during June to October 2010. The NASA Land Information System (LIS) was employed to study the impacts of the SPoRT-MODIS GVF dataset on a land surface model (LSM) apart from a full numerical weather prediction (NWP) model. For the 2010 warm season, the SPoRT GVF in the western portion of the CONUS was generally higher than the NCEP climatology. The eastern CONUS GVF had variations both above and below the climatology during the period of study. These variations in GVF led to direct impacts on the rates of heating and evaporation from the land surface. In the West, higher latent heat fluxes prevailed, which enhanced the rates of evapotranspiration and soil moisture depletion in the LSM. By late Summer and Autumn, both the average sensible and latent heat fluxes increased in the West as a result of the more rapid soil drying and higher coverage of GVF. The impacts of the SPoRT GVF dataset on NWP was also examined for a single severe weather case study using the Weather Research and Forecasting (WRF) model. Two separate coupled LIS/WRF model simulations were made for the 17 July 2010 severe weather event in the Upper Midwest using the NCEP and SPoRT GVFs, with all other model parameters remaining the same. Based on the sensitivity results, regions with higher GVF in the SPoRT model runs had higher evapotranspiration and

  12. Heat in the Barents Sea: transport, storage, and surface fluxes

    Directory of Open Access Journals (Sweden)

    L. H. Smedsrud

    2010-02-01

    Full Text Available A column model is set up for the Barents Sea to explore sensitivity of surface fluxes and heat storage from varying ocean heat transport. Mean monthly ocean transport and atmospheric forcing are synthesised and force the simulations. Results show that by using updated ocean transports of heat and freshwater the vertical mean hydrographic seasonal cycle can be reproduced fairly well.

    Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production.

    The northern Barents Sea receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss annually in the north. The balance is achieved by a heat loss through long wave radiation all year, removing most of the summer solar heating.

    During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. The Barents Sea responds to such large changes by adjusting temperature and heat loss. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport leads to a spreading of warm water further north.

  13. Seattle Tacoma IAP, Washington. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-06-21

    ground, not freezing. Freezing rain and/or freezin zle ( glaze ) - Precipitation falling in liquid form, but freezing on contact with an unheated...8217We n -STO.2 nut m 0mI ALL WEATHER 1800-2000 ClAm W.- I(L I. SPEED MEAN (KNTS) 1-3 4.6 7- 10 11 - 16 17-21 22.27 28- 33 34.40 41 .47 48 . 55 󈧼

  14. Lubbock Regional Airport, Texas. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-11-12

    FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 7 267 LUBOCK REGIONAL ARPT TX 73-81 ALUG ALL WEATHER 1 ]0-ZC02 SPEED MEAN IN’S) 5.- 4.-6 7.10...VISIBILITYA!;- EAITHER SF0VlCF/-AC :-’ LUBOCK ;ZE IONAL Af T T - C PERCENTAGE FREQUENCY OF OCCURRENCE FROM HOURLY OBSERVATIONS 672- 6 0. T 6 67 69.1~ 64

  15. Incirlik AB, Adana, Turkey. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A through F.

    Science.gov (United States)

    1977-03-15

    WEATHER SERVICE/MAC 130 INCIALIK Al TURKEY/ADANA 67-74 AE2 09010 STATION STATION NAME YEARS HOUNS 4L. S. T.1 T-.WET SULS TEMPERATURE DEPRESION (F...TURKy/ADANA 6_ _6 JUt_ STAT.ON STATIC. NiAME ER A E OT’*N’[R IR OT -! T..p. WET BULB TEMPERATURE DEPRESION (F) TOTALTOA , r 2! 1. S /o 7 .. . 6 . .i

  16. Weather types across the Caribbean basin and their relationship with rainfall and sea surface temperature

    Science.gov (United States)

    Moron, Vincent; Gouirand, Isabelle; Taylor, Michael

    2016-07-01

    Eight weather types (WTs) are computed over 98.75°W-56.25°W, 8.75°N-31.25°N using cluster analysis of daily low-level (925 hPa) winds and outgoing longwave radiation, without removing the mean annual cycle, by a k-means algorithm from 1979 to 2013. The WTs can be firstly interpreted as snapshots of the annual cycle with a clear distinction between 5 "wintertime" and 3 "summertime" WTs, which account together for 70 % of the total mean annual rainfall across the studied domain. The wintertime WTs occur mostly from late November to late April and are characterized by varying intensity and location of the North Atlantic subtropical high (NASH) and transient synoptic troughs along the northern edge of the domain. Large-scale subsidence dominates the whole basin but rainfall can occur over sections of the basin, especially on the windward shores of the troughs associated with the synoptic waves. The transition between wintertime and summertime WTs is rather abrupt, especially in May. One summertime WT (WT 4) is prevalent in summer, and almost exclusive around late July. It is characterized by strong NASH, fast Caribbean low level jet and rainfall mostly concentrated over the Caribbean Islands, the Florida Peninsula, the whole Central America and the tropical Eastern Pacific. The two remaining summertime WTs display widespread rainfall respectively from Central America to Bermuda (WT 5) and over the Eastern Caribbean (WT 6). Both WTs combine reduced regional scale subsidence and weaker Caribbean low-level jet relatively to WT 4. The relationships between WT frequency and El Niño Southern Oscillation (ENSO) events are broadly linear. Warm central and eastern ENSO events are associated with more WT 4 (less WT 5-6) during boreal summer and autumn (0) while this relationship is reversed during boreal summer (+1) for central events only. In boreal winter, the largest anomalies are observed for two WTs consistent with negative (WT 2) and positive (WT 8) phases of the

  17. Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Timothy D.; Babauta, Jerome T.; Davenport, Emily K.; Renslow, Ryan S.; Beyenal, Haluk

    2015-05-01

    We investigated ion transport limitations on 3D graphite felt electrodes by growing Geobacter sulfurreducens biofilms with advection to eliminate external mass transfer limitations. We characterized ion transport limitations by: (i) showing that serially increasing NaCl concentration up to 200mM increased current linearly up to a total of þ273% vs. 0mM NaCl under advective conditions; (ii) growing the biofilm with a starting concentration of 200mM NaCl, which led to a maximum current increase of 400% vs. current generation without NaCl, and (iii) showing that un-colonized surface area remained even after steadystate current was reached. After accounting for iR effects, we confirmed that the excess surface area existed despite a non-zero overpotential. The fact that the biofilm was constrained from colonizing and producing further current under these conditions confirmed the biofilms under study here were ion transport-limited. Our work demonstrates that the use of high surface area electrodes may not increase current density when the system design allows ion transport limitations to become dominant.

  18. Quantum Transport and Surface Scattering in Magnetic Metallic Film

    Institute of Scientific and Technical Information of China (English)

    HU Yin; DONG Zheng-Chao

    2008-01-01

    Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,we present a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) for surface roughness is described by a Gaussion model.Our result shows that the conductivity is a sensitive function of surface roughness and exchange energy.It is also found that in the thin film limit and in the lower-order approximation of the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spin channels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.

  19. Different Multifractal Scaling of the 0 cm Average Ground Surface Temperature of Four Representative Weather Stations over China

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2013-01-01

    Full Text Available The temporal scaling properties of the daily 0 cm average ground surface temperature (AGST records obtained from four selected sites over China are investigated using multifractal detrended fluctuation analysis (MF-DFA method. Results show that the AGST records at all four locations exhibit strong persistence features and different scaling behaviors. The differences of the generalized Hurst exponents are very different for the AGST series of each site reflecting the different scaling behaviors of the fluctuation. Furthermore, the strengths of multifractal spectrum are different for different weather stations and indicate that the multifractal behaviors vary from station to station over China.

  20. A pre-Paleogene unconformity surface of the Sikeshu Sag, Junggar Basin: Lithological, geophysical and geochemical implications for the transportation of hydrocarbons

    Directory of Open Access Journals (Sweden)

    Xiaoyue Gao

    2013-11-01

    Full Text Available The unconformity surface at the bottom of the Paleogene is one of the most important migration pathways in the Sikeshu Sag of the Junggar Basin, which consists of three layers: upper coarse clastic rock, lower weathering crust and leached zone. The upper coarse clastic rock is characterized by higher density and lower SDT and gamma-ray logging parameters, while the lower weathering crust displays opposite features. The transport coefficient of the unconformity surface is controlled by its position in respect to the basal sandstone; it is higher in the ramp region but lower in the adjacent uplifted and sag areas. The content of saturated hydrocarbons increases with the decrease of the content of non-hydrocarbons and asphaltenes. The content of benzo[c] carbazole decreases as the content of benzo[a] carbazole and [alkyl carbazole]/[alkyl + benzo carbazole] increases. This suggests that the unconformity surface is an efficient medium for the transportation of hydrocarbons.

  1. Band bending and electrical transport at chemically modified silicon surfaces

    Science.gov (United States)

    Lopinski, Greg; Ward, Tim; Hul'Ko, Oleksa; Boukherroub, Rabah

    2002-03-01

    High resolution electron energy loss spectroscopy (HREELS) and electrical transport measurements have been used to investigate how various chemical modifications give rise to band bending and alter the conductivity of Si(111) surfaces. HREELS is a sensitive probe of band bending through observations of the low frequency free carrier plasmon mode. For hydrogen terminated surfaces, prepared by the standard etch in ammonium flouride, HREELS measurements on both n and n+ substrates are consistent with nearly flat bands. Chlorination of these surfaces results in substantial upward band bending due to the strong electron withdrawing nature of the chlorine, driving the surface into inversion. The presence of this inversion layer on high resistivity n-type samples is observed through a substantial enhancement of the surface conductivity (relative to the H-terminated surface), as well as through broadening of the quasi-elastic peak in the HREELS measurements. We have also begun to examine organically modified silicon surfaces, prepared by various wet chemical reactions with the H-terminated surface. Decyl modified Si(111) surfaces are seen to exhibit a small degree of band bending, attributed to extrinsic defect states cause by a small degree of oxidation accompanying the modification reaction. The prospects of using conductivity as an in-situ monitor of the rate of these reactions will be discussed.

  2. Fort Campbell AAF, Clarksville, Kentucky. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    Science.gov (United States)

    1975-07-10

    FROM HOURLY OBSERVATIONS) 13806 FO~RT CA;*,PSFLL KY/ CAMPRELL AAF 43-45,t5-72 AUG STATION STATIONM ARC ?"Its MONTH (ALL V4,FATKER 1200-1400 CLASS... CAMPRELL AAF 44-45P50-72 APR STATKO, STATIO’ N E Y. "s ONT. PERCENTAGE FREQUENCY OF OCCURRENCE 12o-o (FROM HOURLY OBSERVATIONS) VISIBLITY (STATUTE MILES...T.,S 0EM Ate OM.CITE ( UDATA PRUCESS, b,"ACCh USAF ETAC CEILING VERSUS VISIBILITY AIR WEATHER SERVICE/MAC + 13806 FORT CAMPBELL KY/ CAMPRELL AAF 4"A

  3. Daggett Municipal, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-07-02

    T~TATT I Am maL imlr ALL WEATHER �-2300 SP1EED1 MEAN (KNTS) 1 -3 4. 6 7-10 11 16 17. 21 22-27 2 6 33 34-40 41 . 4 - 55 t56 % WIND R. - SPEED e...000,0100.0100.0 - 98.4 996 1 99.2 990, 99.,p 99.9 99.9 99.99,v o.Olo.o 1 .oO,,o~ Ojo .oEo.01 TOTA NUMUI OF0SERVATIONS 748 USAF fTC 0. 4.5 :L A, low- An 0

  4. Myrtle Beach AFB South Carolina. Revised Uniform Summary of Surface Weather Observations. Parts A-F

    Science.gov (United States)

    1975-07-03

    falling to the ground, not freezing. Freeziag rain and/or freezing drizzle ( glaze ) - Precipitation falling in liquid form, but freezing on contact...13717 0YRTLE DFACh AFB SOUTH CAROLINA 43-47.,49-72 APR TATION STATION Nut TANS MONTH . ALL WE.ATHER ALL CLASS MOlUS (L.S.T.) C CONDITION SPEED...19_ 111 902~. * 131 36/ 251 r 51 5v k V~2 117 Z 32/ 311 .4. 51 5_ 12i 81~ - - I4 . C 26/ 27~ L L . I____l ’ I 6 20 19 t -__ __I El- nut (X) I x

  5. Droplet Transport Mechanism on Horizontal Hydrophilic/Hydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook [Kookmin University, Seoul (Korea, Republic of)

    2014-06-15

    A fluid transport technique is a key issue for the development of microfluidic systems. In this study, the movement of a droplet on horizontal hydrophilic/hydrophobic surfaces, which is a new concept to transport droplets without external power sources that was recently proposed by the author, was simulated using an in-house solution code(PowerCFD). This code employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The droplet transport mechanism is examined through numerical results that include velocity vectors, pressure contours, and total kinetic energy inside and around the droplet.

  6. Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

    Science.gov (United States)

    Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

    2015-08-01

    The dissolved nickel (Ni) isotopic composition of rivers and oceans presents an apparent paradox. Even though rivers represent a major source of Ni in the oceans, seawater is more enriched in the heavier isotopes than river-water. Additional sources or processes must therefore be invoked to account for the isotopic budget of dissolved Ni in seawater. Weathering of continental rocks is thought to play a major role in determining the magnitude and sign of isotopic fractionation of metals between a rock and the dissolved product. We present a study of Ni isotopes in the rock-soil-plant systems of several ultramafic environments. The results reveal key insights into the magnitude and the control of isotopic fractionation during the weathering of continental ultramafic rocks. This study introduces new constraints on the influence of vegetation during the weathering process, which should be taken into account in interpretations of the variability of Ni isotopes in rivers. The study area is located in a temperate climate zone within the ophiolitic belt area of Albania. The serpentinized peridotites sampled present a narrow range of heavy Ni isotopic compositions (δ60Ni = 0.25 ± 0.16 ‰, 2SD n = 2). At two locations, horizons within two soil profiles affected by different degrees of weathering all presented light isotopic compositions compared to the parent rock (Δ60Nisoil-rock up to - 0.63 ‰). This suggests that the soil pool takes up the light isotopes, while the heavier isotopes remain in the dissolved phase. By combining elemental and mineralogical analyses with the isotope compositions determined for the soils, the extent of fractionation was found to be controlled by the secondary minerals formed in the soil. The types of vegetation growing on ultramafic-derived soils are highly adapted and include both Ni-hyperaccumulating species, which can accumulate several percent per weight of Ni, and non-accumulating species. Whole-plant isotopic compositions were found

  7. Impact of additional surface observation network on short range weather forecast during summer monsoon 2008 over Indian subcontinent

    Indian Academy of Sciences (India)

    Prashant Kumar; Randhir Singh; P C Joshi; P K Pal

    2011-02-01

    The three dimensional variational data assimilation scheme (3D-Var) is employed in the recently developed Weather Research and Forecasting (WRF) model. Assimilation experiments have been conducted to assess the impact of Indian Space Research Organisation’s (ISRO) Automatic Weather Stations (AWS) surface observations (temperature and moisture) on the short range forecast over the Indian region. In this study, two experiments, CNT (without AWS observations) and EXP (with AWS observations) were made for 24-h forecast starting daily at 0000 UTC during July 2008. The impact of assimilation of AWS surface observations were assessed in comparison to the CNT experiment. The spatial distribution of the improvement parameter for temperature, relative humidity and wind speed from one month assimilation experiments demonstrated that for 24-h forecast, AWS observations provide valuable information. Assimilation of AWS observed temperature and relative humidity improved the analysis as well as 24-h forecast. The rainfall prediction has been improved due to the assimilation of AWS data, with the largest improvement seen over the Western Ghat and eastern India.

  8. Surface Diffusion Effect on Gas Transport in Nanoporous Materials

    Science.gov (United States)

    Hori, Takuma; Yoshimoto, Yuta; Takagi, Shu; Kinefuchi, Ikuya

    2016-11-01

    Polymer electrolyte fuel cells are one of the promising candidates for power sources of electric vehicles. For further improvement of their efficiency in high current density operation, a better understanding of oxygen flow inside the cells, which have micro- or nanoporous structures, is necessary. Molecular simulations such as the direct simulation of Monte Carlo (DSMC) are necessary to elucidate flow phenomena in micro- or nanostructures since the Knudsen number is close to unity. Our previous report showed that the oxygen diffusion resistance in porous structures with a characteristic pore size of 100 nm calculated by DSMC agrees well with that measured experimentally. On the other hand, when it comes to the transport in structures with much smaller pore sizes, it is expected that the surface diffusion has a significant impact on gas transport because of their higher specific surface area. Here we present the calculation of gas transport in porous structures with considering surface diffusion. The numerical porous structure models utilized in our simulations are constructed from three-dimensional imaging of materials. The effect of the distance of random walk on the total diffusion resistance in the structures is discussed. This paper is based on results obtained from a project commissioned by the New Energy and Industrial Development Organization (NEDO).

  9. Siegenberg Germany Gunnery Range, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1971-10-28

    PERrORMING OGANZ𔃺.. %k.4E A% tD ADODESS b E t E’ U SAFETAC/OL-A A .6_q 1 S 5 Air Force Environmental Technical Appl. Center Scott AFB IL 62225 1% ’K...INNERY RANGE 64070 JUL S51ONSAT-CV NAE YER S=N PERCENTAGE FREQUENCY OF OCCURRENCE OF WEATHER CONDZTIONS FROM HOURLY OBSERVATIONS MONTH HOS T .RAIN...10 !1 - .6 17 . 21 22 - 27 28 -33 34 40 Al - 48 55 >$6 % WIND DIR. AS " S EE D N. 7! 00 Is 798_--4,61’T NN ENE td ;1 _____ 1 - 3j~Z~ SSE $61 . -_ 1

  10. Influence of surface modified nano silica on alkyd binder before and after accelerated weathering

    DEFF Research Database (Denmark)

    Nikolic, Miroslav; Nguyen, Hiep Dinh; Daugaard, Anders Egede

    2016-01-01

    Introduction of nano fillers in exterior wood coatings is not straight forward. Influence on aging of polymer binder needs to be taken into account along with possible benefits that nano fillers can provide immediately after application. This study shows the influence of two differently modified...... hydrophobic nano silica on an alkyd binder for exterior wood coatings. One month after application, the highest strength and energy required to break the films was obtained with addition of 3% disilazane modified silica. Changes in tensile properties were accompanied with a small increase in glass transition...... temperature. However, the highest stability upon accelerated weathering, measured by ATR-IR and DMA, was for nano composites with the highest amount of nano filler. The reasons for the observed changes are discussed together with the appearance of a feature that is possibly a secondary relaxation of alkyd...

  11. Friendship IAP, Maryland. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-05-04

    USAFETAC PSYCHROMETRIC SUMMARY’k A1 dEATHER SERVXCE/MAC STATIO STATION 041A vt LS MONT. PAGE I1 - i(Fl WI~III~i~i1IIi ET SUL& TESIPEXATUnE DEPRESION (F...WEATHER SERVICE/MAC L2AD0. FRIENDOSHIP IAP MD 74-S1orf STATION STATION *464 VtAAS M. PAGE 2 -nn-nn Th.~.WIT SUL$ TEMPERATURE DEPRESION (F) ITOTAL TOTAL () 0...Alte WEAT.4ER SERVICE/IAC 776ff F7hnSHTP Ti A mn-t ER STAION NWA YA PAGE 1 WE? BULB TEMPERATURE DEPRESION (F) TOTAL 1 TOTAL (I 0 1.2 j3-43. 7. 9. . 1o 1

  12. Slippery Liquid-Infused Porous Surfaces and Droplet Transportation by Surface Acoustic Waves

    Science.gov (United States)

    Luo, J. T.; Geraldi, N. R.; Guan, J. H.; McHale, G.; Wells, G. G.; Fu, Y. Q.

    2017-01-01

    On a solid surface, a droplet of liquid will stick due to the capillary adhesion, and this causes low droplet mobility. To reduce contact line pinning, surface chemistry can be coupled to micro- and/or nanostructures to create superhydrophobic surfaces on which a droplet balls up into an almost spherical shape, thus, minimizing the contact area. Recent progress in soft matter has now led to alternative lubricant-impregnated surfaces capable of almost zero contact line pinning and high droplet mobility without causing droplets to ball up and minimize the contact area. Here we report an approach to surface-acoustic-wave- (SAW) actuated droplet transportation enabled using such a surface. These surfaces maintain the contact area required for efficient energy and momentum transfer of the wave energy into the droplet while achieving high droplet mobility and a large footprint, therefore, reducing the threshold power required to induce droplet motion. In our approach, we use a slippery layer of lubricating oil infused into a self-assembled porous hydrophobic layer, which is significantly thinner than the SAW wavelength, and avoid damping of the wave. We find a significant reduction (up to 85%) in the threshold power for droplet transportation compared to that using a conventional surface-treatment method. Moreover, unlike droplets on superhydrophobic surfaces, where interaction with the SAW induces a transition from a Cassie-Baxter state to a Wenzel state, the droplets on our liquid-impregnated surfaces remain in a mobile state after interaction with the SAW.

  13. Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

    Science.gov (United States)

    Niiya, Hirofumi; Nishimura, Kouichi

    2017-05-01

    We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from 10-5 to 10 m above the flat surface. The numerical results are as follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below 10 cm and gradual wind response above 10 cm. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below 100 µm remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above 300 µm is less than the wind speed, whereas that below 300 µm exceeds the wind speed because of descending particles. (v) The particle diameter increases with height in the saltation layer, and the relationship is expressed as a power function. Through comparisons with the previously reported random-flight model, we find a crucial problem that empirical splash functions cannot reproduce particle dynamics at a relatively high wind speed.

  14. Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

    CERN Document Server

    Niiya, Hirofumi

    2016-01-01

    We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from $10^{-5} \\hspace{0.5 ex} \\mathrm{m}$ to $10 \\hspace{0.5 ex} \\mathrm{m}$ above the flat surface. The numerical results are s follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below $10 \\hspace{0.5 ex} \\mathrm{cm}$ and gradual wind response above $10 \\hspace{0.5 ex} \\mathrm{cm}$. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below $100 \\hspace{0.5 ex} \\mu\\mathrm{m}$ remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above $300 \\hspace{0.5 ex} \\mu\\mathrm{m}$ is less than the wind speed, whereas that below $300 \\hspace{0.5 ex} \\mu\\mathrm...

  15. Nanoscale electron transport at the surface of a topological insulator

    Science.gov (United States)

    Bauer, Sebastian; Bobisch, Christian A.

    2016-01-01

    The use of three-dimensional topological insulators for disruptive technologies critically depends on the dissipationless transport of electrons at the surface, because of the suppression of backscattering at defects. However, in real devices, defects are unavoidable and scattering at angles other than 180° is allowed for such materials. Until now, this has been studied indirectly by bulk measurements and by the analysis of the local density of states in close vicinity to defect sites. Here, we directly measure the nanoscale voltage drop caused by the scattering at step edges, which occurs if a lateral current flows along a three-dimensional topological insulator. The experiments were performed using scanning tunnelling potentiometry for thin Bi2Se3 films. So far, the observed voltage drops are small because of large contributions of the bulk to the electronic transport. However, for the use of ideal topological insulating thin films in devices, these contributions would play a significant role. PMID:27098939

  16. Nanoscale electron transport at the surface of a topological insulator

    Science.gov (United States)

    Bauer, Sebastian; Bobisch, Christian A.

    2016-04-01

    The use of three-dimensional topological insulators for disruptive technologies critically depends on the dissipationless transport of electrons at the surface, because of the suppression of backscattering at defects. However, in real devices, defects are unavoidable and scattering at angles other than 180° is allowed for such materials. Until now, this has been studied indirectly by bulk measurements and by the analysis of the local density of states in close vicinity to defect sites. Here, we directly measure the nanoscale voltage drop caused by the scattering at step edges, which occurs if a lateral current flows along a three-dimensional topological insulator. The experiments were performed using scanning tunnelling potentiometry for thin Bi2Se3 films. So far, the observed voltage drops are small because of large contributions of the bulk to the electronic transport. However, for the use of ideal topological insulating thin films in devices, these contributions would play a significant role.

  17. TRANSPORT OF BICOMPONENT CONTAMINANT IN FREE-SURFACE WETLAND FLOW

    Institute of Scientific and Technical Information of China (English)

    CHEN Bin; ZENG Li; WU Yi-hong; JI Ping; ZHAO Yi-jun

    2012-01-01

    This paper presents a theoretical analysis of a pulsed bicomponent contaminant emission into a free-surface wetland flow.The basic equations are for the bicomponent contaminant transport in the wetland flow under the combined action of advection,mass dispersion,and ecological reaction at the phase averaged scale.The effect of the ecological reaction is separated from the hydrodynamic effect via a set of widely used transforms.The analytical solution for the evolution of the depth-averaged concentration is rigorously derived,with a limiting case covering the known solution for the single component contaminant transport.It is found that the depth-averaged species concentration of the bicomponent contaminant can approach an equilibrium state determined by the distribution coefficient.

  18. Kimpo-iap K-14, Seoul, Korea. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1973-10-30

    31.4 8,0 37;5 2266 03.05 .1 5.4 .504 3 6.8 6.3 43o2 2279 C 06;0S .2 5.6 5o5 50.6 211, . eo 63.0 2265 S09-.1 .2 4 4, 11.5 2696 35.5 2263 12.1* .1 _0 .0 5.0...SURFACE WINDS AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 4 3 2 n l K IM PJ IA P K ORFA / S EO U...OBSERVATIONS) 412n1 KtMPfl TAP KOR9A/SFDUL K-14 46,4050;71 qgp *TATK 4 StATION NAM& VIAS MONTH ALL W ATHER 12n.-14no CLASS HOURS IL.S.T.) ( CONDITION SPEED

  19. McGuire AFB, New Jersey. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1983-07-20

    2000 78 gUSAFETAC MYMv 0 10 SIOL A), moowmm ofv’F.no m, N wN a - ,/ USAFrTAC 010-5 L J, P’t’O SIlQIS~ttl~t IOItt: c’,.,-- * . *1 GLOBAL CLIMATOLOGY... mm Aon oss O$S i = . ft PA " --- 5LrBAL CLIMATOLOGY BRANCH S AFETAC SURFACE WINDS AIR wEATHER SERVICE/MA" PERCENTAGE FREQUENCY OF WIND DIRECTION AND...FROM HOURLY OBSERVATIONS) ALL hLFAT Hr ClASS mm US?.) SPEED IA KITS) I- 4.6 7.0 1.16 17-21 22 - 27 2 - 33 34.40 41 -47 491.55 2t s6 WIND DIR. _ _ SPEED

  20. Don Muang IAP, Bangkok, Thailand. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1971-04-02

    00,10 10. 0.09, M0.±0.1k., 0..D.’ 0 J AQf 100 98,4100, 00.0100. 100.01001 00. 100,0100,0100, 100.0 00,0 00,o000.0100.0 2: 0 so .00100 1 100,1000 20...SUMMARYOP SURFACE WEATHER OSEAYATM BANGKOK THAILAND/DON WUANG IAP W8ANO 41001 N 13 55 E 100 36 ELEV 33 FT VTOD WMOE 46436 PARTS A-F POR FROM HOURLY OBS JAN...LOCATION STION FROM TO STATIONIrr) BAROMETER DAY 0I Don uang Apt, Thailand /TAF Jan 54 Dee 63 N 13 55 E 100 36 33 39 Ft 24 LOCATION CHANACTEI LOCATION

  1. ClimoBase: Rouse Canadian Surface Observations of Weather, Climate, and Hydrological Variables, 1984-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ClimoBase is a collection of surface climate measurements collected in Northern Canada by Dr. Wayne Rouse between 1984 and 1998 in three locations: Churchill,...

  2. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    Science.gov (United States)

    Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J. M.; Gómez, M. A.; Hortal, A. R.; Martínez-Haya, B.

    2013-10-01

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  3. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, P., E-mail: mportcal@upo.es [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Antúnez, V.; Ortiz, R.; Martín, J.M. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Gómez, M.A. [Instituto Andaluz de Patrimonio Histórico, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Hortal, A.R.; Martínez-Haya, B. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain)

    2013-10-15

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  4. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue. Modelling of uranium transport in the weathered zone at Koongarra, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Hassanizadeh, S.M.; Van de Weerd, H.; Richardson-Van der Poel, M.A. [National Inst. of Public Health and Environmental Protection RIVM, Bilthoven (Netherlands)

    1993-01-01

    Preliminary results of modelling of the dispersion of uranium in the weathered and transition zones are given. In the course of the Alligator Rivers Analogue Project (ARAP) more insight was gained about the formation of the dispersion fan and about the hydrology at Koongarra. The here applied transport modelling strategy takes into account those results. First, a general explanation of Natural Analogue is given, next to a brief description of the ARAP test case, carried out within the INTRAVAL phase 2. INTRAVAL is an international project concerned with the use of mathematical models for predicting the potential transport of radioactive solutes in the geosphere. Following is the analysis of chemical data, necessary for the choice of the modelling approach, for estimation of model inputs and for testing model results. Subsequently, the modelling strategy is expounded and a description is given of METROPOL, the transport code, used for modelling. 11 figs., 2 tabs., 1 appendix, 17 refs.

  5. Gela, Italy, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1983-11-03

    manual table is also presented for surface wind meeting INSTHUINTE CLASS conditions as follows: Ceiling 200 through lh0 feet inclusive with visibility...OBSERVATIONS Ui AFETAC 0 8 5 tCI . A] yo s 0 Oi T’. UMAEo.-St! -I AL L MT AtL’ ~Ck WID T A SURFACE WINDS - F .EArH: ST VI "t L PERCENTAGE FREQUENCY OF WIND...temperature Lombined; tuid again for dry-bulb, wet-bulb, and dew-point tempera - tures separately. Total observations for thc.;e four Items is also

  6. Modeling marine surface microplastic transport to assess optimal removal locations

    Science.gov (United States)

    Sherman, Peter; van Sebille, Erik

    2016-01-01

    Marine plastic pollution is an ever-increasing problem that demands immediate mitigation and reduction plans. Here, a model based on satellite-tracked buoy observations and scaled to a large data set of observations on microplastic from surface trawls was used to simulate the transport of plastics floating on the ocean surface from 2015 to 2025, with the goal to assess the optimal marine microplastic removal locations for two scenarios: removing the most surface microplastic and reducing the impact on ecosystems, using plankton growth as a proxy. The simulations show that the optimal removal locations are primarily located off the coast of China and in the Indonesian Archipelago for both scenarios. Our estimates show that 31% of the modeled microplastic mass can be removed by 2025 using 29 plastic collectors operating at a 45% capture efficiency from these locations, compared to only 17% when the 29 plastic collectors are moored in the North Pacific garbage patch, between Hawaii and California. The overlap of ocean surface microplastics and phytoplankton growth can be reduced by 46% at our proposed locations, while sinks in the North Pacific can only reduce the overlap by 14%. These results are an indication that oceanic plastic removal might be more effective in removing a greater microplastic mass and in reducing potential harm to marine life when closer to shore than inside the plastic accumulation zones in the centers of the gyres.

  7. Site characterization summary report for dry weather surface water sampling upper East Fork Poplar Creek characterization area Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    This report describes activities associated with conducting dry weather surface water sampling of Upper East Fork Poplar Creek (UEFPC) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. This activity is a portion of the work to be performed at UEFPC Operable Unit (OU) 1 [now known as the UEFPC Characterization Area (CA)], as described in the RCRA Facility Investigation Plan for Group 4 at the Oak- Ridge Y-12 Plant, Oak Ridge, Tennessee and in the Response to Comments and Recommendations on RCRA Facility Investigation Plan for Group 4 at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee, Volume 1, Operable Unit 1. Because these documents contained sensitive information, they were labeled as unclassified controlled nuclear information and as such are not readily available for public review. To address this issue the U.S. Department of Energy (DOE) published an unclassified, nonsensitive version of the initial plan, text and appendixes, of this Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) Plan in early 1994. These documents describe a program for collecting four rounds of wet weather and dry weather surface water samples and one round of sediment samples from UEFPC. They provide the strategy for the overall sample collection program including dry weather sampling, wet weather sampling, and sediment sampling. Figure 1.1 is a schematic flowchart of the overall sampling strategy and other associated activities. A Quality Assurance Project Plan (QAPJP) was prepared to specifically address four rounds of dry weather surface water sampling and one round of sediment sampling. For a variety of reasons, sediment sampling has not been conducted and has been deferred to the UEFPC CA Remedial Investigation (RI), as has wet weather sampling.

  8. 49 CFR 195.224 - Welding: Weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Weather. 195.224 Section 195.224 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.224 Welding: Weather. Welding must be protected from weather conditions...

  9. Hurlburt Field, Valparaiso, Florida. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    Science.gov (United States)

    1972-05-25

    TOTA,--- NUBE OF OBSERVATIONS 1--- -7 ’I.. C)AIA PRUCf.SSIN" r.VI ,NI3r 1 TAC(/USA, SURFACE WINDS 2 A WEATtER ShkVLE/ AC PERCENTAGE...T~ NNW ~ 3 110 9 1. 2,6 61__ __ __ __7__ __ Ile- 17 3.9 1-36--1011 10 ___ t ___ o z__ ____ -__ TOTA NUBE OF9 OB.41TON 14407 _____TA __’_ 0 * 8.5 .2

  10. North America Synoptic Weather Maps

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Series of Synoptic Weather Maps. Maps contains a surface analysis comprised of plotted weather station observations, isobars indicating low and high-pressure...

  11. Distribution of Quercus agrifolia mycorrhizae deep within weathered bedrock: a potential mechanism for transport of stored water

    Science.gov (United States)

    M. Bornyasz; R. Graham; M. Allen

    2002-01-01

    In southwestern California, Quercus agrifolia distribution closely matches regions of granitic regolith. High annual evapotranspiration demand and inherent shallow soil conditions lead to a dependence on a deep rooting system and an ability to access water from deep within the regolith. Most of the plant available water in weathered granitic rock is...

  12. Ab initio transport across bismuth selenide surface barriers

    KAUST Repository

    Narayan, Awadhesh

    2014-11-24

    © 2014 American Physical Society. We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi2Se3(111) topological surface states by means of large-scale ab initio transport simulations. Our results demonstrate the suppression of perfect backscattering, while all other scattering processes, which do not entail a complete spin and momentum reversal, are allowed. Furthermore, we find that the spin of the surface state develops an out-of-plane component as it traverses the barrier. Our calculations reveal the existence of quasibound states in the vicinity of the surface barriers, which appear in the form of an enhanced density of states in the energy window corresponding to the topological state. For double barriers we demonstrate the formation of quantum well states. To complement our first-principles results we construct a two-dimensional low-energy effective model and illustrate its shortcomings. Our findings are discussed in the context of a number of recent experimental works.

  13. Retrieving Clear-Sky Surface Skin Temperature for Numerical Weather Prediction Applications from Geostationary Satellite Data

    Directory of Open Access Journals (Sweden)

    Baojuan Shan

    2013-01-01

    Full Text Available Atmospheric models rely on high-accuracy, high-resolution initial radiometric and surface conditions for better short-term meteorological forecasts, as well as improved evaluation of global climate models. Remote sensing of the Earth’s energy budget, particularly with instruments flown on geostationary satellites, allows for near-real-time evaluation of cloud and surface radiation properties. The persistence and coverage of geostationary remote sensing instruments grant the frequent retrieval of near-instantaneous quasi-global skin temperature. Among other cloud and clear-sky retrieval parameters, NASA Langley provides a non-polar, high-resolution land and ocean skin temperature dataset for atmospheric modelers by applying an inverted correlated k-distribution method to clear-pixel values of top-of-atmosphere infrared temperature. The present paper shows that this method yields clear-sky skin temperature values that are, for the most part, within 2 K of measurements from ground-site instruments, like the Southern Great Plains Atmospheric Radiation Measurement (ARM Infrared Thermometer and the National Climatic Data Center Apogee Precision Infrared Thermocouple Sensor. The level of accuracy relative to the ARM site is comparable to that of the Moderate-resolution Imaging Spectroradiometer (MODIS with the benefit of an increased number of daily measurements without added bias or increased error. Additionally, matched comparisons of the high-resolution skin temperature product with MODIS land surface temperature reveal a level of accuracy well within 1 K for both day and night. This confidence will help in characterizing the diurnal and seasonal biases and root-mean-square differences between the retrievals and modeled values from the NASA Goddard Earth Observing System Version 5 (GEOS-5 in preparation for assimilation of the retrievals into GEOS-5. Modelers should find the immediate availability and broad coverage of these skin temperature

  14. Use of weather research and forecasting model outputs to obtain near-surface refractive index structure constant over the ocean.

    Science.gov (United States)

    Qing, Chun; Wu, Xiaoqing; Li, Xuebin; Zhu, Wenyue; Qiao, Chunhong; Rao, Ruizhong; Mei, Haipin

    2016-06-13

    The methods to obtain atmospheric refractive index structure constant (Cn2) by instrument measurement are limited spatially and temporally and they are more difficult and expensive over the ocean. It is useful to forecast Cn2 effectively from Weather Research and Forecasting Model (WRF) outputs. This paper introduces a method that WRF Model is used to forecast the routine meteorological parameters firstly, and then Cn2 is calculated based on these parameters by the Bulk model from the Monin-Obukhov similarity theory (MOST) over the ocean near-surface. The corresponding Cn2 values measured by the micro-thermometer which is placed on the ship are compared with the ones forecasted by WRF model to determine how this method performs. The result shows that the forecasted Cn2 is consistent with the measured Cn2 in trend and the order of magnitude as a whole, as well as the correlation coefficient is up to 77.57%. This method can forecast some essential aspects of Cn2 and almost always captures the correct magnitude of Cn2, which experiences fluctuations of two orders of magnitude. Thus, it seems to be a feasible and meaningful method that using WRF model to forecast near-surface Cn2 value over the ocean.

  15. On the contribution of lakes in predicting near-surface temperature in a global weather forecasting model

    Directory of Open Access Journals (Sweden)

    T. Stockdale

    2012-02-01

    Full Text Available The impact of lakes in numerical weather prediction is investigated in a set of global simulations performed with the ECMWF Integrated Forecasting System (IFS. A Fresh shallow-water Lake model (FLake is introduced allowing the coupling of both resolved and subgrid lakes (those that occupy less than 50% of a grid-box to the IFS atmospheric model. Global fields for the lake ancillary conditions (namely lake cover and lake depth, as well as initial conditions for the lake physical state, have been derived to initialise the forecast experiments. The procedure for initialising the lake variables is described and verified with particular emphasis on the importance of surface water temperature and freezing conditions. The response of short-range near surface temperature to the representation of lakes is examined in a set of forecast experiments covering one full year. It is shown that the impact of subgrid lakes is beneficial, reducing forecast error over the Northern territories of Canada and over Scandinavia particularly in spring and summer seasons. This is mainly attributed to the lake thermal effect, which delays the temperature response to seasonal radiation forcing.

  16. Taipei IAP, Taiwan. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1973-09-07

    TOTA NUBE OP5 OBS3RVATIONS A 22 N6 Fb 6 3 1 USAFETAC FOM 0-8-S (0. A) PREAIOS EDITION$ Of THIS FORM ARE OBSOLETE vV TAe C/usA SURFACE WINDS tIi .EAr E4...4_. s a 4? TOTA NUBE 04OSSAIN -26 ls--- at 4, 1 3,7. L sW 1.5 1,41 ,61 .4.1 4 NW~ lo l 7 .,1 ,1 17 2 ,51 0N 1591 10.9 1.,8 10.9

  17. Mechanics of weathered clay-marl rock masses along the rupture surface in homogeneous dry slopes

    Directory of Open Access Journals (Sweden)

    Kostić Srđan

    2016-01-01

    Full Text Available Authors analyze stress-strain distribution within slope using the shear stress reduction technique based on finite element method, which was previously confirmed to provide approximately the same results as the Janbu's corrected limit equilibrium method. Results obtained indicate that the largest vertical displacements occur at the slope base and crest, while central part of the slope is exposed to the largest horizontal displacements. Normal and shear stress show maximum values in the middle part of the slope. It was also determined that separate stress-strain relations could be derived for the exact upper and lower part of the rupture surface. [Projekat Ministarstva nauke Republike Srbije, br. 37005

  18. Ternary Complexation on Bacterial Surfaces: Implications for Subsurface Anion Transport

    Science.gov (United States)

    Maclean, L. C.; Higginbottom, C. M.; Fowle, D. A.

    2002-12-01

    The physical, chemical, and biological controls on contaminant mobilities in aquatic ecosystems must be determined to establish the threat that contamination poses to the environment. Quantitative models of contaminant mobilities are required as a prerequisite to guide remediation efforts and to prioritize the potential hazard to the ecosystem of each contaminated site. It is well established that mineral surface adsorption is an important control on contaminant mobilities, and many studies have utilized thermodynamics to quantify metal/organic adsorption in order to yield predictive models of contaminant transport. However, these models of contaminant transport may not be representative of the reactions which control contaminant mobilities as most mineral surfaces are coated with organic acids, bacteria, and extracellular polymers. Numerous laboratory studies have demonstrated that bacterial cell walls have a high affinity for binding metal cations, and field studies indicate that a significant proportion of bacteria cells and associated extracellular matrices are coated with small scale hydrous metal oxides. The small size of bacteria, and in many cases the nanoscale of their associated mineral phases, suggests these bacteria-mineral composites may represent a large proportion of surface area exposed to fluid flow. Therefore, due to the affinity of bacterial cell walls for cations and biominerals, bacteria may also have a significant impact on anionic contaminant mobility in many natural systems. The extent of metal-bacteria adsorption reactions varies drastically as a function of pH and solution chemistry. Current adsorption models have focused on the interactions of positively charged metal cations with bacterial surfaces, however in many oxidizing environments metals such as Cr exist as anions or anionic complexes. We have studied the ability of non-metabolizing cells of the bacterial species Bacillus subtilis and Shewanella putrifaciens to adsorb aqueous Cr

  19. Geostatistical improvements of evapotranspiration spatial information using satellite land surface and weather stations data

    Science.gov (United States)

    de Carvalho Alves, Marcelo; de Carvalho, Luiz Gonsaga; Vianello, Rubens Leite; Sediyama, Gilberto C.; de Oliveira, Marcelo Silva; de Sá Junior, Arionaldo

    2013-07-01

    The objective of the present study was to use the simple cokriging methodology to characterize the spatial variability of Penman-Monteith reference evapotranspiration and Thornthwaite potential evapotranspiration methods based on Moderate Resolution Imaging Spetroradiometer (MODIS) global evapotranspiration products and high-resolution surfaces of WordClim temperature and precipitation data. The climatic element data referred to 39 National Institute of Meteorology climatic stations located in Minas Gerais state, Brazil and surrounding states. The use of geostatistics and simple cokriging technique enabled the characterization of the spatial variability of the evapotranspiration providing uncertainty information on the spatial prediction pattern. Evapotranspiration and precipitation surfaces were implemented for the climatic classification in Minas Gerais. Multivariate geostatistical determined improvements of evapotranspiration spatial information. The regions in the south of Minas Gerais derived from the moisture index estimated with the MODIS evapotranspiration (2000-2010), presented divergence of humid conditions when compared to the moisture index derived from the simple kriged and cokriged evapotranspiration (1961-1990), indicating climate change in this region. There was stronger pattern of crossed covariance between evapotranspiration and precipitation rather than temperature, indicating that trends in precipitation could be one of the main external drivers of the evapotranspiration in Minas Gerais state, Brazil.

  20. Coupled Soil Water and Heat Transport Near the Land Surface in Arid and Semiarid Regions - Multi-Domain Modeling

    Science.gov (United States)

    Mohanty, Binayak; Yang, Zhenlei

    2016-04-01

    Understanding and simulating coupled water and heat transfer appropriately in the shallow subsurface is of vital significance for accurate prediction of soil evaporation that would improve the coupling between land surface and atmosphere, which consequently could enhance the reliability of weather as well as climate forecast. The theory of Philip and de Vries (1957), accounting for water vapor diffusion only, was considered physically incomplete and consequently extended and improved by several researchers by explicitly taking water vapor convection, dispersion or air flow into account. It is generally believed that the soil moisture is usually low in the near surface layer under highly transient field conditions, particularly in arid and semiarid regions, and that accurate characterization of water vapor transport is critical when modeling simultaneous water and heat transport in the shallow field soils. The first objective of this study is thus mainly to test existing coupled water and heat transport theories and to develop reasonable and simplified numerical models using field experimental data collected under semi-arid and arid hydro-climatic conditions. In addition, more complex multi-domain models are developed for ubiquitous heterogeneous terrestrial surfaces such as horizontal textural contrasts or structured heterogeneity including macropores (fractures, cracks, root channels, etc.). This would make coupled water and heat transfer models applicable in such non-homogeneous soils more meaningful and enhance the skill of land-atmosphere interaction models at a larger context.

  1. Evaporation and weather

    NARCIS (Netherlands)

    Bruin, H.A.R. de; Feddes, R.A.; Holtslag, A.A.M.; Lablans, W.N.; Schuurmans, C.J.E.; Shuttleworth, W.J.

    1987-01-01

    Data on evaporation to be used in agriculture, hydrology, forestry, etc. are usually supplied by meteorologists. Meteorologists themselves also use evaporation data. Air mass properties determining weather are strongly dependent on the input of water vapour from the surface. So for weather

  2. Evaporation and weather

    NARCIS (Netherlands)

    Bruin, H.A.R. de; Feddes, R.A.; Holtslag, A.A.M.; Lablans, W.N.; Schuurmans, C.J.E.; Shuttleworth, W.J.

    1987-01-01

    Data on evaporation to be used in agriculture, hydrology, forestry, etc. are usually supplied by meteorologists. Meteorologists themselves also use evaporation data. Air mass properties determining weather are strongly dependent on the input of water vapour from the surface. So for weather predictio

  3. Taegu AB, Korea. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A, C-F.

    Science.gov (United States)

    1981-10-07

    USAETAC 0.6.5 (OL*A) MviOUS 101TIONS Of THIS OIM S A OSS ITIl ~1------------ -- ---- -- -- -- -- -- -- - GLL.AL CLIMATOLOUY PRANCH LS r7ETAC SURFACE...1 5 > ~16 . 0 NOCEILING 4’.5 6 . 1 ol. 6 . ,7.5 69:4 7 .7 7. 7 .4 71.5 ’ 𔃻 TI 71.5 1 -1. C . - 20000 5% b ’S1. 6 ? ś ".,95 7?.6 73.9 74 74.7 7j S...61.6 51 .9 61 .9 b I o 6 . 6Z 6 2.5 b2t Q2.5 .> 20000 , ,. 2 b 2 4 6 3 o 4 6 r. 6 5 .6 a ’. 8 6 5 . , 65 o 5 ,:o 4 6 0 4 6 6 4 6 6 . 4 S6 0 4 4 6 ? 18000

  4. Selfridge ANGB, Michigan. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-04-20

    PRECIPITATION PSYCMROMETRIC.ORY VS WIT SULS SNOWFALL MEAN & STD DIV.- 104Y SULI, WET 9UL6, & DEW POINT)SNOW DEPTH obAasvTim SURFACE WINDS P REATIJV UIDITY...5_000 i 1 "n. ir.| -,11 - l I-7A_n aI.* B17 . -7. 7’P~ Lier I2t f hA ) A 2 4 ft-A.:P, 48l )I~ - 7 9 ai 1. ;:, . 0. 51.3 51.7 51.8 52.0 52.0 52.3 2s.3...SELfRIOBE Atd6I "I 69-712.74-ak CPAGE I1 WIT OLS TOMMATUS ONUSS IV) TOTAL TOTAL (p) 2 1- 4s 6 J7- 4 i011 i. . 1 . 1 Iii 1 I I I I III.II . 1 3 I 60% 6 4 1 V

  5. Advanced computer technology - An aspect of the Terminal Configured Vehicle program. [air transportation capacity, productivity, all-weather reliability and noise reduction improvements

    Science.gov (United States)

    Berkstresser, B. K.

    1975-01-01

    NASA is conducting a Terminal Configured Vehicle program to provide improvements in the air transportation system such as increased system capacity and productivity, increased all-weather reliability, and reduced noise. A typical jet transport has been equipped with highly flexible digital display and automatic control equipment to study operational techniques for conventional takeoff and landing aircraft. The present airborne computer capability of this aircraft employs a multiple computer simple redundancy concept. The next step is to proceed from this concept to a reconfigurable computer system which can degrade gracefully in the event of a failure, adjust critical computations to remaining capacity, and reorder itself, in the case of transients, to the highest order of redundancy and reliability.

  6. Monthly Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface Weather Observation 1001 Forms is a set of historical manuscript records for the period 1893-1948. The collection includes two very similar form types: Form...

  7. Coupled Stochastic Time-Inverted Lagrangian Transport/Weather Forecast and Research/Vegetation Photosynthesis and Respiration Model. Part II; Simulations of Tower-Based and Airborne CO2 Measurements

    Science.gov (United States)

    Eluszkiewicz, Janusz; Nehrkorn, Thomas; Wofsy, Steven C.; Matross, Daniel; Gerbig, Christoph; Lin, John C.; Freitas, Saulo; Longo, Marcos; Andrews, Arlyn E.; Peters, Wouter

    2007-01-01

    This paper evaluates simulations of atmospheric CO2 measured in 2004 at continental surface and airborne receptors, intended to test the capability to use data with high temporal and spatial resolution for analyses of carbon sources and sinks at regional and continental scales. The simulations were performed using the Stochastic Time-Inverted Lagrangian Transport (STILT) model driven by the Weather Forecast and Research (WRF) model, and linked to surface fluxes from the satellite-driven Vegetation Photosynthesis and Respiration Model (VPRM). The simulations provide detailed representations of hourly CO2 tower data and reproduce the shapes of airborne vertical profiles with high fidelity. WRF meteorology gives superior model performance compared with standard meteorological products, and the impact of including WRF convective mass fluxes in the STILT trajectory calculations is significant in individual cases. Important biases in the simulation are associated with the nighttime CO2 build-up and subsequent morning transition to convective conditions, and with errors in the advected lateral boundary condition. Comparison of STILT simulations driven by the WRF model against those driven by the Brazilian variant of the Regional Atmospheric Modeling System (BRAMS) shows that model-to-model differences are smaller than between an individual transport model and observations, pointing to systematic errors in the simulated transport. Future developments in the WRF model s data assimilation capabilities, basic research into the fundamental aspects of trajectory calculations, and intercomparison studies involving other transport models, are possible venues for reducing these errors. Overall, the STILT/WRF/VPRM offers a powerful tool for continental and regional scale carbon flux estimates.

  8. Convective Weather Avoidance with Uncertain Weather Forecasts

    Science.gov (United States)

    Karahan, Sinan; Windhorst, Robert D.

    2009-01-01

    Convective weather events have a disruptive impact on air traffic both in terminal area and in en-route airspaces. In order to make sure that the national air transportation system is safe and efficient, it is essential to respond to convective weather events effectively. Traffic flow control initiatives in response to convective weather include ground delay, airborne delay, miles-in-trail restrictions as well as tactical and strategic rerouting. The rerouting initiatives can potentially increase traffic density and complexity in regions neighboring the convective weather activity. There is a need to perform rerouting in an intelligent and efficient way such that the disruptive effects of rerouting are minimized. An important area of research is to study the interaction of in-flight rerouting with traffic congestion or complexity and developing methods that quantitatively measure this interaction. Furthermore, it is necessary to find rerouting solutions that account for uncertainties in weather forecasts. These are important steps toward managing complexity during rerouting operations, and the paper is motivated by these research questions. An automated system is developed for rerouting air traffic in order to avoid convective weather regions during the 20- minute - 2-hour time horizon. Such a system is envisioned to work in concert with separation assurance (0 - 20-minute time horizon), and longer term air traffic management (2-hours and beyond) to provide a more comprehensive solution to complexity and safety management. In this study, weather is dynamic and uncertain; it is represented as regions of airspace that pilots are likely to avoid. Algorithms are implemented in an air traffic simulation environment to support the research study. The algorithms used are deterministic but periodically revise reroutes to account for weather forecast updates. In contrast to previous studies, in this study convective weather is represented as regions of airspace that pilots

  9. 36 CFR 13.460 - Use of snowmobiles, motorboats, dog teams, and other means of surface transportation...

    Science.gov (United States)

    2010-07-01

    ... transportation in accordance with 43 CFR 36.11(c), (d), (e), and (g). ..., motorboats, dog teams, and other means of surface transportation traditionally employed by local rural... of snowmobiles, motorboats, dog teams, and other means of surface transportation...

  10. Weather and emotional state

    Science.gov (United States)

    Spasova, Z.

    2010-09-01

    Introduction Given the proven effects of weather on the human organism, an attempt to examine its effects on a psychic and emotional level has been made. Emotions affect the bio-tonus, working ability and concentration, hence their significance in various domains of economic life, such as health care, education, transportation, tourism, etc. Data and methods The research has been made in Sofia City within a period of 8 months, using 5 psychological methods (Eysenck Personality Questionnaire (EPQ), State-Trait Anxiety Inventory (STAI), Test for Self-assessment of the emotional state (developed by Wessman and Ricks), Test for evaluation of moods and Test "Self-confidence - Activity - Mood" (developed by the specialists from the Military Academy in Saint Petersburg). The Fiodorov-Chubukov's complex-climatic method was used to characterize meteorological conditions because of the purpose to include in the analysis a maximal number of meteorological elements. 16 weather types are defined in dependence of the meteorological elements values according to this method. Abrupt weather changes from one day to another, defined by the same method, were considered as well. Results and discussions The results obtained by t-test show that the different categories of weather lead to changes in the emotional status, which indicates a character either positive or negative for the organism. The abrupt weather changes, according to expectations, have negative effect on human emotions but only when a transition to the cloudy weather or weather type, classified as "unfavourable" has been realized. The relationship between weather and human emotions is rather complicated since it depends on individual characteristics of people. One of these individual psychological characteristics, marked by the dimension "neuroticism", has a strong effect on emotional reactions in different weather conditions. Emotionally stable individuals are more "protected" to the weather influence on their emotions

  11. Modeling sheet-flow sand transport under progressive surface waves

    NARCIS (Netherlands)

    Kranenburg, W.M.

    2013-01-01

    In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels. Howeve

  12. Surface trap mediated electronic transport in biofunctionalized silicon nanowires

    Science.gov (United States)

    Puppo, F.; Traversa, F. L.; Di Ventra, M.; De Micheli, G.; Carrara, S.

    2016-08-01

    Silicon nanowires (SiNWs), fabricated via a top-down approach and then functionalized with biological probes, are used for electrically-based sensing of breast tumor markers. The SiNWs, featuring memristive-like behavior in bare conditions, show, in the presence of biomarkers, modified hysteresis and, more importantly, a voltage memory component, namely a voltage gap. The voltage gap is demonstrated to be a novel and powerful parameter of detection thanks to its high-resolution dependence on charges in proximity of the wire. This unique approach of sensing has never been studied and adopted before. Here, we propose a physical model of the surface electronic transport in Schottky barrier SiNW biosensors, aiming at reproducing and understanding the voltage gap based behavior. The implemented model describes well the experimental I-V characteristics of the device. It also links the modification of the voltage gap to the changing concentration of antigens by showing the decrease of this parameter in response to increasing concentrations of the molecules that are detected with femtomolar resolution in real human samples. Both experiments and simulations highlight the predominant role of the dynamic recombination of the nanowire surface states, with the incoming external charges from bio-species, in the appearance and modification of the voltage gap. Finally, thanks to its compactness, and strict correlation with the physics of the nanodevice, this model can be used to describe and predict the I-V characteristics in other nanostructured devices, for different than antibody-based sensing as well as electronic applications.

  13. Modelling surface drifting of buoys during a rapidly-moving weather front in the Gulf of Finland, Baltic Sea

    Science.gov (United States)

    Gästgifvars, Maria; Lauri, Hannu; Sarkanen, Annakaisa; Myrberg, Kai; Andrejev, Oleg; Ambjörn, Cecilia

    2006-12-01

    The Gulf of Finland is an elongated estuary located in the north-eastern extremity of the Baltic Sea. This semi-enclosed sea-area is subject to heavy sea traffic, and is one of the main risk areas for oil accidents in the Baltic. The continuous development and validation of operational particle drift and oil-spill forecasting systems is thus seen to be essential for this sea-area. Here, the results of a three-day drift experiment in May 2003 are discussed. The field studies were performed using GPS-positioned surface floating buoys. The aim of this paper is to evaluate how well models can reproduce the drift of these buoys. Model simulations, both in forecast and hindcast modes, were carried out by three different 3D hydrodynamic models, the results of which are evaluated by comparing the calculated drifts with observations. These models were forced by HIRLAM (High Resolution Limited Area Model) and ECMWF (European Centre for Medium-Range Weather Forecasts) meteorological forecast fields. The simulated drift of the buoys showed a good agreement with observations even when, during the study period, a rapidly-changing wind situation was observed to affect the investigation area; in this situation the winds turned about 100 degrees in half an hour. In such a case it is a very complicated task to forecast the drifters' routes: there is a need to regularly update the meteorological forcing fields and to use these regularly-updated fields throughout the simulations. It is furthermore recommended that forecasts should be made using several circulation models and several meteorological forecasts, in order to get an overview of the accuracy of the forecasted drifts and related differences in between the forecasts.

  14. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    NARCIS (Netherlands)

    Bhattacharjee, S.; Opstal, van E.J.; Alink, G.M.; Marcelis, A.T.M.; Zuilhof, H.; Rietjens, I.M.C.M.

    2013-01-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/s

  15. Laboratory studies of aeolian sediment transport processes on planetary surfaces

    Science.gov (United States)

    Rasmussen, Keld R.; Valance, Alexandre; Merrison, Jonathan

    2015-09-01

    , but not all, older or recent wind tunnel observations. Similarly some measurements performed with uniform sand samples having grain diameters of the order of 0.25-0.40 mm indicate that ripple spacing depends on friction velocity in a similar way as particle jump length. The observations are thus in agreement with a recent ripple model that link the typical jump length to ripple spacing. A possible explanation for contradictory observations in some experiments may be that long observation sequences are required in order to assure that equilibrium exists between ripple geometry and wind flow. Quantitative understanding of saltation characteristics on Mars still lacks important elements. Based upon image analysis and numerical predictions, aeolian ripples have been thought to consist of relatively large grains (diameter > 0.6 mm) and that saltation occurs at high wind speeds (> 26 m/s) involving trajectories that are significantly longer than those on Earth (by a factor of 10-100). However, this is not supported by recent observations from the surface of Mars, which shows that active ripples in their geometry and composition have characteristics compatible with those of terrestrial ripples (Sullivan et al., 2008). Also the highest average wind speeds on Mars have been measured to be terrestrial conditions electric fields typically observed are not intense enough to significantly affect sand transport rates while little is known in the case of extra-terrestrial environments.

  16. Ubon RTAFB, Ubon Ratchathani, Thailand. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1971-03-02

    593 ADA 09696 1 ’HANI DATA PROCESSING DIVISION USAF ETAC Air Weather Service ( MAC ) .;: DI HFORM SUMMARY OF ’,CE WEATHER OBSERVATIONS UDON ...1jjn.oilc0o. TOTAL NUMBER OF OBSERVAIIONS 11 r USAIFTA( 𔃾 ’OL1, .. AT 𔃻 K f I I IV/ISI !N A CEILING VERSUSVISIBILITY 𔃾 17 1. n, AC-’A THANI T,,A /I T...41017 Ui8N RATCNATHANI THAI/ UdON RTAFO 66-70 FEFi STATION STATION AME PERIOo ONT CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE (FROM HOURLY OBSERVATIONS

  17. Kinetic Space Weather: Toward a Global Hybrid Model of the Polar Ionosphere-Lower Magnetosphere Plasma Transport

    Science.gov (United States)

    Horwitz, James L.

    1996-01-01

    During the indicated period of performance, we had a number of publications concerned with kinetic polar ionosphere-lower magnetosphere plasma transport. For the IUGG 1991-4 Quadrennial Report, we reviewed aspects of U.S. accomplishments concerned with polar plasma transport, among other issues. In another review, we examined the computer simulations of multiple-scale processes in space plasmas, including polar plasma outflow and transport. We also examined specifically multiscale processes in ionospheric outflows. We developed a Generalized Semi-Kinetic(GSK) model for the topside-lower magnetosphere which explored the synergistic action of wave heating and electric potentials in the formation of auroral Ion conics, in particular the "pressure cooker" mechanism. We extended the GSK model all the way down to 120 km and applied this code to illustrate the response of the ionosphere- magnetosphere to soft-electron precipitation and convection-driven frictional ion heating, respectively. Later, the convection-driven heating work was extended to a paper for the Journal of Geophysical Research. In addition to the above full published papers, we also presented the first developments of the coupled fluid-semikinetic model for polar plasma transport during this period. The results from a steady-state treatment were presented, with the second presentation being concerned with the effects of photo-electrons on the polar wind, and the first garnering an outstanding student paper award from the American Geophysical Union. We presented the first results from a time-dependent version of this coupled fluid-semikinetic model.

  18. Storm and fair-weather driven sediment-transport within Poverty Bay, New Zealand, evaluated using coupled numerical models

    Science.gov (United States)

    Bever, Aaron J.; Harris, Courtney K.

    2014-09-01

    The Waipaoa River Sedimentary System in New Zealand, a focus site of the MARGINS Source-to-Sink program, contains both a terrestrial and marine component. Poverty Bay serves as the interface between the fluvial and oceanic portions of this dispersal system. This study used a three-dimensional hydrodynamic and sediment-transport numerical model, the Regional Ocean Modeling System (ROMS), coupled to the Simulated WAves Nearshore (SWAN) wave model to investigate sediment-transport dynamics within Poverty Bay and the mechanisms by which sediment travels from the Waipaoa River to the continental shelf. Two sets of model calculations were analyzed; the first represented a winter storm season, January-September, 2006; and the second an approximately 40 year recurrence interval storm that occurred on 21-23 October 2005. Model results indicated that hydrodynamics and sediment-transport pathways within Poverty Bay differed during wet storms that included river runoff and locally generated waves, compared to dry storms driven by oceanic swell. During wet storms the model estimated significant deposition within Poverty Bay, although much of the discharged sediment was exported from the Bay during the discharge pulse. Later resuspension events generated by Southern Ocean swell reworked and modified the initial deposit, providing subsequent pulses of sediment from the Bay to the continental shelf. In this manner, transit through Poverty Bay modified the input fluvial signal, so that the sediment characteristics and timing of export to the continental shelf differed from the Waipaoa River discharge. Sensitivity studies showed that feedback mechanisms between sediment-transport, currents, and waves were important within the model calculations.

  19. Wacky Weather

    Science.gov (United States)

    Sabarre, Amy; Gulino, Jacqueline

    2013-01-01

    What do a leaf blower, water hose, fan, and ice cubes have in common? Ask the students who participated in an integrative science, technology, engineering, and mathematics (I-STEM) education unit, "Wacky Weather," and they will tell say "fun and severe weather"--words one might not have expected! The purpose of the unit…

  20. Wacky Weather

    Science.gov (United States)

    Sabarre, Amy; Gulino, Jacqueline

    2013-01-01

    What do a leaf blower, water hose, fan, and ice cubes have in common? Ask the students who participated in an integrative science, technology, engineering, and mathematics (I-STEM) education unit, "Wacky Weather," and they will tell say "fun and severe weather"--words one might not have expected! The purpose of the unit…

  1. Rhein-Main Apt, Germany/Franfurt. Revised Uniform Summary of Surface Weather Observations. Parts A-F

    Science.gov (United States)

    1977-08-01

    DATA PROCESSING BRANCH usAF E’ C CEILING, VERSUS VISIBILITY AIR WEATHER SERVICE/MAC 0 RHEINMAIN APT GERMANY/FRAtKFURT...SERVICE/MAC RHEINMAIN APT GENMANY/FRANKFURT 67-7o OEZ U. PERCENTAGE FREQUENCY OF OCCURRENCE 0000-.)200 , (FROM HOURLY OBSERVATIONS) o , - VISIBILITY

  2. Bad Tolz AAF, Bad Tolz, Germany. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1972-01-26

    PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 417.. BADL 01-2 OER MANY AAF ---67 STATION STATION kANS VI.$ No 1. ALL WEATHER 21...and aruual for all years Tcc , ... ase pab !atior.s rovide the caunalative percentae fre..ency to tenths of temperature by 5-degrea ’ahrcnheit

  3. The effect of surface transport on water desalination by porous electrodes undergoing capacitive charging

    CERN Document Server

    Shocron, Amit N

    2016-01-01

    Capacitive deionization (CDI) is a technology in which water is desalinated by ion electrosorption into the electric double layers (EDLs) of charging porous electrodes. In recent years significant advances have been made in modeling the charge and salt dynamics in a CDI cell, but the possible effect of surface transport within diffuse EDLs on these dynamics has not been investigated. We here present theory which includes surface transport in describing the dynamics of a charging CDI cell. Through our numerical solution to the presented models, the possible effect of surface transport on the CDI process is elucidated. While at some model conditions surface transport enhances the rate of CDI cell charging, counter-intuitively this additional transport pathway is found to slow down cell charging at other model conditions.

  4. Surface electronic transport measurements: A micro multi-point probe approach

    DEFF Research Database (Denmark)

    Barreto, Lucas

    2014-01-01

    setup, but the terminology used and data analysis were also ameliorated in order to simplify the interpretation of the results. We used the mentioned technique in the following projects: • The electronic transport dimensionality of epitaxial grahene grown on SiC is detected and important physical......This work is mostly focused on the study of electronic transport properties of two-dimensional materials, in particular graphene and topological insulators. To study these, we have improved a unique micro multi-point probe instrument used to perform transport measurements. Not only the experimental...... a direct measurement of the surface electronic transport on a bulk topological insulator. The surface state conductivity and mobility are obtained. Apart from transport properties, we also investigate the atomic structure of the Bi2Se3(111) surface via surface x-ray diraction and low-energy electron...

  5. WARP Weather Information Network Server

    Data.gov (United States)

    Department of Transportation — WINS is the dissemination module of the WARP system that provides an interface to various NAS Users/systems that require weather data/products/information from WARP...

  6. Aeolian transport in the field: A comparison of the effects of different surface treatments

    Science.gov (United States)

    Dong, Zhibao; Lv, Ping; Zhang, Zhengcai; Qian, Guangqiang; Luo, Wanyin

    2012-05-01

    Aeolian transport represents the result of wind-surface interactions, and therefore depends strongly on variations in the characteristics of the sediment surface. We conducted field observations of aeolian transport of typical dune sand in three 80 m × 80 m plots with different surface treatments: gravel-covered sand, enclosed shifting sand, and open (unprotected) shifting sand. The study was performed at the Shapotou Aeolian Experiment Site in the southeastern part of China's Tengger Desert to compare the effects of these different surface treatments on aeolian transport. To do so, we analyzed the flux density profiles and transport rates above each surface. The flux density profiles for all three treatments followed the exponential decay law that was proposed by most previous researchers to describe the saltation flux density profiles. Coefficients of the exponential decay function were defined as a function of the surface and the wind velocity. The enclosed and open plots with shifting sand had similar flux density profiles, but the flux density above gravel-covered plots showed that transport decayed more slowly with increasing height, producing flux density profiles with a higher average saltation height. The transport rate above the three treatment plots tended to increase proportionally with the cube of the mean wind velocity and with the maximum wind velocity during the observation period, but was more strongly correlated with the square of drift potential. Transport rates above the plot with open shifting sand were greater than those above the plots with enclosed shifting sand and the gravel-covered plot.

  7. Vehicle Emission Inspection and Maintenance (I/M) Provision in the Fixing America’s Surface Transportation (FAST) Act

    Science.gov (United States)

    This document is a memorandum regarding Vehicle Emission Inspection and Maintenance (I/M) Provision in Fixing America's Surface Transportation (FAST) Act, which provides long-term funding certainty for surface transportation infrastructure planning

  8. Nha Trang Apt.,Vietnam. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1971-01-29

    38. 38, e *2 120 2.1 6 2 8 82 6 * 6 o5 6 62 62 .62. 62. 62 .62. 62. 62, 62- 62. 2000oo 62, 62.21 . 2:1 .62:; ,2, 2: big : a 6 62, 62 62. ?-16000 3...10 - I _ __ - - - - - -_ V * ADATA PROCESSING OIVISIONV USAF ETAC CEILING VERSUS VISIBILITY S AIR WEATHER SERVICE/MAC 41010

  9. Investigating Surface Bias Errors in the Weather Research and Forecasting (WRF) Model using a Geographic Information System (GIS)

    Science.gov (United States)

    2015-02-01

    horizontal grid spacing inner domain centered near San Diego, California. The San Diego area contains a mixture of urban , suburban, agricultural, and...Global Forecast System (GFS) model (Environmental Modeling Center 2003). The WRE–N is envisioned to be a rapid-update cycling application of WRF–ARW...surface– hydrology model with the Penn State-NCAR MM5 modeling system. Part I: Model implementation and sensitivity. Monthly Weather Review. 2001a

  10. Weathering behaviour of overburden-coal ash blending in relation to overburden management for acid mine drainage prevention in coal surface mine

    Energy Technology Data Exchange (ETDEWEB)

    Gautama, R.S.; Kusuma, G.J.; Lestari, I.; Anggana, R.P. [Bandung Inst. Teknologi (Indonesia). Dept. of Mining Engineering, Faculty of Mining and Petroleum Engineering

    2010-07-01

    Potentially acid forming (PAF) materials are encapsulated with non-acid forming materials (NAF) in order to prevent acid mine drainage (AMD) in surface coal mines. NAF compaction techniques with fly and bottom ashes from coal-fired power plants are used in mines with limited amounts of NAF materials. This study investigated the weathering behaviour of blended overburden and coal combustion ash in laboratory conditions. Free draining column leach tests were conducted on different blending schemes. The weathering process was simulated by spraying the samples with de-ionized water once per day. The leachates were then analyzed using X-ray diffraction and fluorescence analyses in order to identify the mineral composition of the samples over a 14 week period. Results of the study indicated that the weathering process plays a significant role in controlling infiltration rates, and may increase the capability of capping materials to prevent infiltration into PAF materials. Fly- and bottom-ash additions improved the performance of the encapsulation materials. 3 refs., 4 tabs., 2 figs.

  11. Determination of Granite Rock Massif Weathering and Cracking of Surface Layers in the Oldest Parts of Medieval Mine Depending on Used Mining Method

    Science.gov (United States)

    Lednická, Markéta; Kaláb, Zdeněk

    2016-06-01

    The paper presents the use of selected non-destructive testing methods for the purpose of specifying information on weathering and cracking of surface layers of granite rock massif in the medieval Jeroným Mine (the Czech Republic). This mine has been declared the National Heritage Site of the Czech Republic and its opening as a mining museum to the public is gradually prepared. Geological and geomechanical evaluation documents the possibility to find all kinds of weathering grades of rock massif in this mine. Two non-destructive methods have been tested, namely the measurement of ultrasonic pulse velocity and the measurement of Schmidt hammer rebound value. Field measurements were performed in two selected galleries to verify the application of such methods in specific conditions of underground spaces. Used mining method is one of the parameters later influencing cracking of rock massif. In selected galleries, two different mining methods were used which means that a part of a gallery profile was mined out by hand tools in the Middle Ages and another part of the profile was later mined out by blasting. Measurements in these galleries have enabled to analyse the influence of used mining methods on cracking of rock massif in the impaired zone, and, consequently, on ongoing weathering processes in those zones.

  12. Mirador - Weather

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Our weather system includes the dynamics of the atmosphere and its interaction with the oceans and land. The improvement of...

  13. On Limiting Behavior of Contaminant Transport Models in Coupled Surface and Groundwater Flows

    Directory of Open Access Journals (Sweden)

    Vincent J. Ervin

    2015-11-01

    Full Text Available There has been a surge of work on models for coupling surface-water with groundwater flows which is at its core the Stokes-Darcy problem. The resulting (Stokes-Darcy fluid velocity is important because the flow transports contaminants. The analysis of models including the transport of contaminants has, however, focused on a quasi-static Stokes-Darcy model. Herein we consider the fully evolutionary system including contaminant transport and analyze its quasi-static limits.

  14. Serotonin-induced down-regulation of cell surface serotonin transporter

    DEFF Research Database (Denmark)

    Jørgensen, Trine Nygaard; Christensen, Peter Møller; Gether, Ulrik

    2014-01-01

    The serotonin transporter (SERT) terminates serotonergic signaling and enables refilling of synaptic vesicles by mediating reuptake of serotonin (5-HT) released into the synaptic cleft. The molecular and cellular mechanisms controlling SERT activity and surface expression are not fully understood...

  15. 75 FR 9638 - Surface Transportation Project Delivery Pilot Program; Caltrans Audit Report

    Science.gov (United States)

    2010-03-03

    ...; 49 CFR 1.48. Issued on: February 23, 2010. Victor M. Mendez, Administrator. Surface Transportation... Chapter 25 references FHWA Order 6640.2 FHWA Actions to address Environmental Justice in minority and...

  16. Transport Rate of Surface Erosion by the Hydrodynamics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The coherence and exposure degree are used in analyzing initiation of slope sediment.The initial ve- locity is built by using a critical roiling model.A transport rate formula of slope erosion is established using the Meyer-Peter model.The formula is tested by experiment and agrees well but the errors are big when the flow discharge and rain intensity are smaller.

  17. Updated global soil map for the Weather Research and Forecasting model and soil moisture initialization for the Noah land surface model

    Science.gov (United States)

    DY, C. Y.; Fung, J. C. H.

    2016-08-01

    A meteorological model requires accurate initial conditions and boundary conditions to obtain realistic numerical weather predictions. The land surface controls the surface heat and moisture exchanges, which can be determined by the physical properties of the soil and soil state variables, subsequently exerting an effect on the boundary layer meteorology. The initial and boundary conditions of soil moisture are currently obtained via National Centers for Environmental Prediction FNL (Final) Operational Global Analysis data, which are collected operationally in 1° by 1° resolutions every 6 h. Another input to the model is the soil map generated by the Food and Agriculture Organization of the United Nations - United Nations Educational, Scientific and Cultural Organization (FAO-UNESCO) soil database, which combines several soil surveys from around the world. Both soil moisture from the FNL analysis data and the default soil map lack accuracy and feature coarse resolutions, particularly for certain areas of China. In this study, we update the global soil map with data from Beijing Normal University in 1 km by 1 km grids and propose an alternative method of soil moisture initialization. Simulations of the Weather Research and Forecasting model show that spinning-up the soil moisture improves near-surface temperature and relative humidity prediction using different types of soil moisture initialization. Explanations of that improvement and improvement of the planetary boundary layer height in performing process analysis are provided.

  18. Enhanced Thermal Transport of Surfaces with Superhydrophobic Coatings

    Science.gov (United States)

    2015-07-01

    Deposition 4 3. Results/ Analysis 5 4. Conclusion 7 5. References 8 Distribution List 9 iv List of Figures Fig. 1 Contact angle...by measuring the contact angle (σ) formed between a droplet of liquid and the surface (Fig. 1). Qualitatively , surfaces with a water contact angle...several seconds and dried with filtered nitrogen. The samples were then immersed in 0.01-M aqueous solution of silver nitrate for 20 s. The deposition

  19. Interannual variability of surface and bottom sediment transport on the Laptev Sea shelf during summer

    Directory of Open Access Journals (Sweden)

    C. Wegner

    2012-09-01

    Full Text Available Sediment transport dynamics were studied during ice-free conditions under different atmospheric circulation regimes on the Laptev Sea shelf (Siberian Arctic. To study the interannual variability of suspended particulate matter (SPM dynamics and their coupling with the variability in surface river water distribution on the Laptev Sea detailed oceanographic, optical (turbidity and Ocean Color satellite data, and hydrochemical (nutrients, SPM, stable oxygen isotopes process studies were carried out continuously during the summers of 2007 and 2008. Thus, for the first time SPM and nutrient variations on the Laptev Sea shelf under different atmospheric forcing and the implications for the turbidity and transparency of the water column can be presented.

    The data indicate a clear link between different surface distributions of riverine waters and the SPM transport dynamics within the entire water column. The summer of 2007 was dominated by shoreward winds and an eastward transport of riverine surface waters. The surface SPM concentration on the south-eastern inner shelf was elevated, which led to decreased transmissivity and increased light absorption. Surface SPM concentrations in the Central and Northern Laptev Sea were comparatively low. However, the SPM transport and concentration within the bottom nepheloid layer increased considerably on the entire eastern shelf. The summer of 2008 was dominated by offshore-winds and northwards transport of the river plume. The surface SPM transport was enhanced and extended onto the mid-shelf whereas the bottom SPM transport and concentration was diminished. This study suggests that the SPM concentration and transport in both, the surface and bottom nepheloid layers, are associated with the distribution of riverine surface waters which are linked to the atmospheric circulation patterns over the Laptev Sea and the adjacent Arctic Ocean during open water season. A continuing trend toward shoreward winds

  20. 49 CFR 192.231 - Protection from weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Protection from weather. 192.231 Section 192.231 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... weather. The welding operation must be protected from weather conditions that would impair the quality...

  1. Subarctic physicochemical weathering of serpentinized peridotite

    Science.gov (United States)

    Ulven, O. I.; Beinlich, A.; Hövelmann, J.; Austrheim, H.; Jamtveit, B.

    2017-06-01

    Frost weathering is effective in arctic and subarctic climate zones where chemical reactions are limited by the reduced availability of liquid water and the prevailing low temperature. However, small scale mineral dissolution reactions are nevertheless important for the generation of porosity by allowing infiltration of surface water with subsequent fracturing due to growth of ice and carbonate minerals. Here we combine textural and mineralogical observations in natural samples of partly serpentinized ultramafic rocks with a discrete element model describing the fracture mechanics of a solid when subject to pressure from the growth of ice and carbonate minerals in surface-near fractures. The mechanical model is coupled with a reaction-diffusion model that describes an initial stage of brucite dissolution as observed during weathering of serpentinized harzburgites and dunites from the Feragen Ultramafic Body (FUB), SE-Norway. Olivine and serpentine are effectively inert at relevant conditions and time scales, whereas brucite dissolution produces well-defined cm to dm thick weathering rinds with elevated porosity that allows influx of water. Brucite dissolution also increases the water saturation state with respect to hydrous Mg carbonate minerals, which are commonly found as infill in fractures in the fresh rock. This suggests that fracture propagation is at least partly driven by carbonate precipitation. Dissolution of secondary carbonate minerals during favorable climatic conditions provides open space available for ice crystallization that drives fracturing during winter. Our model reproduces the observed cm-scale meandering fractures that propagate into the fresh part of the rock, as well as dm-scale fractures that initiate the breakup of larger domains. Rock disintegration increases the reactive surface area and hence the rate of chemical weathering, enhances transport of dissolved and particulate matter in the weathering fluid, and facilitates CO2 uptake by

  2. Development of a New Data Tool for Computing Launch and Landing Availability with Respect to Surface Weather

    Science.gov (United States)

    Burns, K. Lee; Altino, Karen

    2008-01-01

    The Marshall Space Flight Center Natural Environments Branch has a long history of expertise in the modeling and computation of statistical launch availabilities with respect to weather conditions. Their existing data analysis product, the Atmospheric Parametric Risk Assessment (APRA) tool, computes launch availability given an input set of vehicle hardware and/or operational weather constraints by calculating the climatological probability of exceeding the specified constraint limits, APRA has been used extensively to provide the Space Shuttle program the ability to estimate impacts that various proposed design modifications would have to overall launch availability. The model accounts for both seasonal and diurnal variability at a single geographic location and provides output probabilities for a single arbitrary launch attempt. Recently, the Shuttle program has shown interest in having additional capabilities added to the APRA model, including analysis of humidity parameters, inclusion of landing site weather to produce landing availability, and concurrent analysis of multiple sites, to assist in operational landing site selection. In addition, the Constellation program has also expressed interest in the APRA tool, and has requested several additional capabilities to address some Constellation-specific issues, both in the specification and verification of design requirements and in the development of operations concepts. The combined scope of the requested capability enhancements suggests an evolution of the model beyond a simple revision process. Development has begun for a new data analysis tool that will satisfy the requests of both programs. This new tool, Probabilities of Atmospheric Conditions and Environmental Risk (PACER), will provide greater flexibility and significantly enhanced functionality compared to the currently existing tool.

  3. Cockpit weather information system

    Science.gov (United States)

    Tu, Jeffrey Chen-Yu (Inventor)

    2000-01-01

    Weather information, periodically collected from throughout a global region, is periodically assimilated and compiled at a central source and sent via a high speed data link to a satellite communication service, such as COMSAT. That communication service converts the compiled weather information to GSDB format, and transmits the GSDB encoded information to an orbiting broadcast satellite, INMARSAT, transmitting the information at a data rate of no less than 10.5 kilobits per second. The INMARSAT satellite receives that data over its P-channel and rebroadcasts the GDSB encoded weather information, in the microwave L-band, throughout the global region at a rate of no less than 10.5 KB/S. The transmission is received aboard an aircraft by means of an onboard SATCOM receiver and the output is furnished to a weather information processor. A touch sensitive liquid crystal panel display allows the pilot to select the weather function by touching a predefined icon overlain on the display's surface and in response a color graphic display of the weather is displayed for the pilot.

  4. KSC Shuttle APT, Titusville, Florida. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1979-11-06

    o vus " usvenS.u V = Sowp vtt 4ete - 4*h* Iy (,L( AL LIIM LTtILUry tsPA’C 2 J 5 AJ-;t.AL WEATHER CONDITIONS AIR. i-ATHR SERVTCFIAC 128tW K.jC SrITTL r...0 O0 .0 *0 00 75 .0 s0 .0 Ill .0, .0 .0 40 R,00 . 76 .1 .d go~ 0 . .0 .0 so so 00 00 __ so TRAC td *0 00 .0 .q 0 .0 00 .0 TRA0 70 -A~ 0 .~. 0 *0 .0

  5. Hamilton AFB, San Rafael, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A through F

    Science.gov (United States)

    1972-11-03

    QIILLT1y M4,rrTCA7ITA1 -It G-YY1CA"T rrL- U? kiy iL~jD ItISTRIIIUTON STAMP LEGIBLY. 80 ~ 1104 DATE RECEIVED) IN l) TIC 1I11OTOGRMPII TIS SIfEF~r AND...wihTompotatute Dry sulb 79 93W~ 127T974., D0610 SO* A 9 F s2 RPM ~ ~ Z,7-- - - - - - -- - -w’ DATA PRUCESSING DIV;SIQN3 USO FTAC PSYCHROMETRIC SUMMARY "AIR WEATHER

  6. Biggs AAF, El Paso, Texas. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1981-01-14

    BGSAF E AO 38 U -OOTN FRO HORL OLOBLECIMAOLOYIONS Hoti !S WEATHER CONDITLOONS MONTH CRMS I AD/OR jRAIN &,cRj ANDOR MAIL -B A’ D/OR WITH 015? NO. OF (L5 W...0_____ Fs 32_FJa067 F 73F 0 F -93 F Total . -,-.. ;. .." "I ~ q " -," " * ’f 41 v>"K~ ’ ’, ,Jim j - - ’ ArTA C PSYCHROMETRIC SUMMARY L. < el’ AT.Ft? SUIV

  7. Hydrogen mediated transport of Sn to Ru film surface

    NARCIS (Netherlands)

    Faradzhev, N.; Sidorkin, V.

    2009-01-01

    The authors report on the interaction of atomic hydrogen with Sn and thin Ru film at room temperature. The study is done using a combination of photoelectron and low energy ion scattering spectroscopies as well as scanning electron microscopy. The adsorption of hydrogen on a Sn surface leads to the

  8. Hydrogen mediated transport of Sn to Ru film surface

    NARCIS (Netherlands)

    Faradzhev, N.; Sidorkin, V.

    2009-01-01

    The authors report on the interaction of atomic hydrogen with Sn and thin Ru film at room temperature. The study is done using a combination of photoelectron and low energy ion scattering spectroscopies as well as scanning electron microscopy. The adsorption of hydrogen on a Sn surface leads to the

  9. Impacts of Weather Conditions Modified by Urban Expansion on Surface Ozone:Comparison between the Pearl River Delta and Yangtze River Delta Regions

    Institute of Scientific and Technical Information of China (English)

    WANG Xuemei; CHEN Fei; WU Zhiyong; ZHANG Meigen; Mukul TEWARI; Alex GUENTHER; Christine WIEDINMYER

    2009-01-01

    In this paper,the online weather research and forecasting and chemistry (WRF-Chem) model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta(PRD) and Yangtze River Delta(YRD) regions.Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s (pre-urbanization) and the current urban distribution in the PRD and the YRD.Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃ and 1.4℃,respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime (0.5 to 2 m s-1).The daytime increase in the PBL height (>200 m) is also larger than the nighttime (50-100 m).The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD.Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime.In addition to modifying individual meteorological variables,urbanization also enhances the convergence zones,especially in the PRD.More importantly,urbanization has different effects on the surface ozone for the PRD and the YRD,presumably due to their urbanization characteristics and geographical locations.Even though the PRD has a smaller increase in the surface temperature than the YRD,it has (a) weaker surface wind speed,(b)smaller increase in PBL heights,and (c) stronger convergence zones.The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.

  10. Transport mechanism of an initially spherical droplet on a combined hydrophilic/hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook; Kwon, Young Hoo [Dept. of Mechanical Engineering, Kookmin University, Seoul (Korea, Republic of)

    2015-11-15

    Fluid transport is a key issue in the development of microfluidic systems. Recently, Myong (2014) has proposed a new concept for droplet transport without external power sources, and numerically validated the results for a hypothetical 2D shape, initially having a hemicylindrical droplet shape. Myong and Kwon (2015) have also examined the transport mechanism for an actual water droplet, initially having a 3D hemispherical shape, on a horizontal hydrophilic/hydrophobic surface, based on the numerical results of the time evolution of the droplet shape, as well as the total kinetic, gravitational, pressure and surface free energies inside the droplet. In this study, a 3D numerical analysis of an initially spherical droplet is carried out to establish a new concept for droplet transport. Further, the transport mechanism of an actual water droplet is examined in detail from the viewpoint of the capillarity force imbalance through the numerical results of droplet shape and various energies inside the droplet.

  11. Modeling Fate and Transport of Rotavirus in Surface Flow by Integrating WEPP and a Pathogen Transport Model

    Science.gov (United States)

    Bhattarai, R.; Kalita, P. K.; Davidson, P. C.; Kuhlenschmidt, M. S.

    2012-12-01

    More than 3.5 million people die each year from a water related diseases in this world. Every 20 seconds, a child dies from a water-related illness. Even in a developed country like the United States, there have been at least 1870 outbreaks associated with drinking water during the period of 1920 to 2002, causing 883,806 illnesses. Most of these outbreaks are resulted due to the presence of microbial pathogens in drinking water. Rotavirus infection has been recognized as the most common cause of diarrhea in young children throughout the world. Laboratory experiments conducted at the University of Illinois have demonstrated that recovery of rotavirus has been significantly affected by climatic and soil-surface conditions like slope, soil types, and ground cover. The objective of this study is to simulate the fate and transport of Rotavirus in overland and near-surface flow using a process-based model. In order to capture the dynamics of sediment-bound pathogens, the Water Erosion Prediction Project (WEPP) is coupled with the pathogen transport model. Transport of pathogens in overland flow can be simulated mathematically by including terms for the concentration of the pathogens in the liquid phase (in suspension or free-floating) and the solid phase (adsorbed to the fine solid particles like clay and silt). Advection, adsorption, and decay processes are considered. The mass balance equations are solved using numerical technique to predict spatial and temporal changes in pathogen concentrations in two phases. Outputs from WEPP simulations (flow velocity, depth, saturated conductivity and the soil particle fraction exiting in flow) are transferred as input for the pathogen transport model. Three soil types and three different surface cover conditions have been used in the experimental investigations. Results from these conditions have been used in calibrating and validating the simulation results. Bare surface conditions have produced very good agreement between

  12. Micro-mapping Meteorite Surfaces on Mars using Microscopic Imager Mosaics — A Tool for Unraveling Weathering History at Meridiani Planum

    Science.gov (United States)

    Ashley, J. W.; Herkenhoff, K. E.; Golombek, M. P.; Johnson, J. R.

    2012-12-01

    Meteorites found on Mars provide valuable insights into martian surface processes. During the course of Mars Exploration Rover (MER) extended missions, Spirit and Opportunity have identified 17 confirmed and candidate meteorites on Mars, most of which are irons. The iron meteorites exhibit morphologies and coatings that communicate complex post-fall exposure histories relevant to an understanding of climate near the martian equator [1-4]. Both chemical and mechanical weathering effects are represented. Among the more significant of these are: 1) cm-scale hollowing, 2) surficial rounding, 3) mass excavation/dissolution and removal, 4) differential etching of kamacite plates and taenite lamellae, revealing Widmanstätten patterns, 5) discontinuous iron oxide coatings, and 6) the effects of cavernous weathering, which often penetrate to rock interiors. Determining the nature, magnitude, and timing of each process and its associated features is a complex problem that will be aided by laboratory experiments, image processing, and careful surface evaluation. Because some features appear to superpose others in ways analogous to stratigraphic relationships, Microscopic Imager (MI) mosaics are useful for sketching "geologic maps" of meteorite surfaces. Employing the techniques of conventional planetary mapping [5], each map was drafted manually using full-resolution MI mosaics and Adobe Photoshop software. Units were selected to represent the oxide coating, dust-coated surfaces, sand-coated surfaces, taenite lamellae, and uncoated metal. Also included are areas in shadow, and regions of blooming caused by specular reflection of metal. Regmaglypt rim crests are presented as lineations. As with stratigraphic relationships, noting embayments and other cross-cutting relationships assists with establishing the relative timing for observed weathering effects. In addition to suggesting alternating sequences of wind and water exposure [1], patterns in oxide coating occurrence show

  13. Microbial Weathering of Olivine

    Science.gov (United States)

    McKay, D. S.; Longazo, T. G.; Wentworth, S. J.; Southam, G.

    2002-01-01

    Controlled microbial weathering of olivine experiments displays a unique style of nanoetching caused by biofilm attachment to mineral surfaces. We are investigating whether the morphology of biotic nanoetching can be used as a biosignature. Additional information is contained in the original extended abstract.

  14. Spatial Transport of Magnetic Flux Surfaces in Strongly Anisotropic Turbulence

    Science.gov (United States)

    Matthaeus, W. H.; Servidio, S.; Wan, M.; Ruffolo, D. J.; Rappazzo, A. F.; Oughton, S.

    2013-12-01

    Magnetic flux surfaces afford familiar descriptions of spatial structure, dynamics, and connectivity of magnetic fields, with particular relevance in contexts such as solar coronal flux tubes, magnetic field connectivity in the interplanetary and interstellar medium, as well as in laboratory plasmas and dynamo problems [1-4]. Typical models assume that field-lines are orderly, and flux tubes remain identifiable over macroscopic distances; however, a previous study has shown that flux tubes shred in the presence of fluctuations, typically losing identity after several correlation scales [5]. Here, the structure of magnetic flux surfaces is numerically investigated in a reduced magnetohydrodynamic (RMHD) model of homogeneous turbulence. Short and long-wavelength behavior is studied statistically by propagating magnetic surfaces along the mean field. At small scales magnetic surfaces become complex, experiencing an exponential thinning. At large scales, instead, the magnetic flux undergoes a diffusive behavior. The link between the diffusion of the coarse-grained flux and field-line random walk is established by means of a multiple scale analysis. Both large and small scales limits are controlled by the Kubo number. These results have consequences for understanding and interpreting processes such as magnetic reconnection and field-line diffusion in plasmas [6]. [1] E. N. Parker, Cosmical Magnetic Fields (Oxford Univ. Press, New York, 1979). [2] J. R. Jokipii and E. N. Parker, Phys. Rev. Lett. 21, 44 (1968). [3] R. Bruno et al., Planet. Space Sci. 49, 1201 (2001). [4] M. N. Rosenbluth et al., Nuclear Fusion 6, 297 (1966). [5] W. H. Matthaeus et al., Phys. Rev. Lett. 75, 2136 (1995). [6] S. Servidio et al., submitted (2013).

  15. Electrical transport properties of graphene on SiO2 with specific surface structures

    OpenAIRE

    Nagashio, K.; Yamashita, T; Nishimura, T.; K. Kita; Toriumi, A.

    2011-01-01

    The mobility of graphene transferred on a SiO2/Si substrate is limited to ~10,000 cm2/Vs. Without understanding the graphene/SiO2 interaction, it is difficult to improve the electrical transport properties. Although surface structures on SiO2 such as silanol and siloxane groups are recognized, the relation between the surface treatment of SiO2 and graphene characteristics has not yet been elucidated. This paper discusses the electrical transport properties of graphene on specific surface stru...

  16. Interplay between hydrophilicity and surface barriers on water transport in zeolite membranes

    Science.gov (United States)

    Fasano, Matteo; Humplik, Thomas; Bevilacqua, Alessio; Tsapatsis, Michael; Chiavazzo, Eliodoro; Wang, Evelyn N.; Asinari, Pietro

    2016-10-01

    A comprehensive understanding of molecular transport within nanoporous materials remains elusive in a broad variety of engineering and biomedical applications. Here, experiments and atomistic simulations are synergically used to elucidate the non-trivial interplay between nanopore hydrophilicity and surface barriers on the overall water transport through zeolite crystals. At these nanometre-length scales, these results highlight the dominating effect of surface imperfections with reduced permeability on the overall water transport. A simple diffusion resistance model is shown to be sufficient to capture the effects of both intracrystalline and surface diffusion resistances, thus properly linking simulation to experimental evidence. This work suggests that future experimental work should focus on eliminating/overcoming these surface imperfections, which promise an order of magnitude improvement in permeability.

  17. Theory connecting nonlocal sediment transport, earth surface roughness, and the Sadler effect

    Science.gov (United States)

    Schumer, Rina; Taloni, Alessandro; Furbish, David Jon

    2017-03-01

    Earth surface evolution, like many natural phenomena typified by fluctuations on a wide range of scales and deterministic smoothing, results in a statistically rough surface. We present theory demonstrating that scaling exponents of topographic and stratigraphic statistics arise from long-time averaging of noisy surface evolution rather than specific landscape evolution processes. This is demonstrated through use of "elastic" Langevin equations that generically describe disturbance from a flat earth surface using a noise term that is smoothed deterministically via sediment transport. When smoothing due to transport is a local process, the geologic record self organizes such that a specific Sadler effect and topographic power spectral density (PSD) emerge. Variations in PSD slope reflect the presence or absence and character of nonlocality of sediment transport. The range of observed stratigraphic Sadler slopes captures the same smoothing feature combined with the presence of long-range spatial correlation in topographic disturbance.

  18. Severe Weather Forecast Decision Aid

    Science.gov (United States)

    Bauman, William H., III; Wheeler, Mark M.; Short, David A.

    2005-01-01

    This report presents a 15-year climatological study of severe weather events and related severe weather atmospheric parameters. Data sources included local forecast rules, archived sounding data, Cloud-to-Ground Lightning Surveillance System (CGLSS) data, surface and upper air maps, and two severe weather event databases covering east-central Florida. The local forecast rules were used to set threat assessment thresholds for stability parameters that were derived from the sounding data. The severe weather events databases were used to identify days with reported severe weather and the CGLSS data was used to differentiate between lightning and non-lightning days. These data sets provided the foundation for analyzing the stability parameters and synoptic patterns that were used to develop an objective tool to aid in forecasting severe weather events. The period of record for the analysis was May - September, 1989 - 2003. The results indicate that there are certain synoptic patterns more prevalent on days with severe weather and some of the stability parameters are better predictors of severe weather days based on locally tuned threat values. The results also revealed the stability parameters that did not display any skill related to severe weather days. An interactive web-based Severe Weather Decision Aid was developed to assist the duty forecaster by providing a level of objective guidance based on the analysis of the stability parameters, CGLSS data, and synoptic-scale dynamics. The tool will be tested and evaluated during the 2005 warm season.

  19. Stallion Site, San Marcial, New Mexico. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A, C through F.

    Science.gov (United States)

    1975-02-21

    N1 2,& 2.6 . . ME _.__,_ 16.- 3 SEE 2.6__ 2...L A SW1 5__ 1 ~ WSW w 2.6 -JL2. WNW _ __ 2r . . (C MW 2a6_ 26_ .8 j, NNW zb 2.6 saA _ _ _ _ _ _ _ _ 1l.1...PROCESSINO SRAHCN SCRM TI U M R 3 USAF ITAG SC R MTICSNM A Y -r AIR WIATHER SIVICEI"AC 1)ohl STALLION 3119 wa Augp&p) E’ STATION STATION NAME ERP G NIONT. T...D ATA PROCESSING BRANCH RLTVoA, PO~l~tN SaA *CNRELATIVE HUMIDITY 3 ETAC/USAF ; G AI|R WEATHER SERVICI/MAC a i $TALLIIIN SITE NM _ _7_

  20. Kobler Field, Saipan, Mariana Island. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1973-04-19

    HOURLY OBSERVATIONS) 41408 KUBLER PLD SAIPAN NAS/MARIANA 45-47,53-62 ALL $TATION STAT...NN[UOT ALL WEATHER ALL CLASS COouS CL *.T.J SPEED MEAN (NTS) 1...FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 414OR KUBLER FLO SAIPAN NAS/I’ARIANA 43#54-62 _ __R ALL WEATHFk ALL cASS -11S 4L 9 T...OBSERVATIONS) 4140 8 KUBLER FLO SAIPAN NAS/4ARIANA 45,47,53-62 mAY ALL wATHFR ALL sPFD 1 F T7 MEAN (KNTS) -3 . 6 7- 10 11 - 16 17 21 22 27 28 .33 34- 40 41

  1. Fort Huachuca, Libby AAF, Arizona. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-04-22

    AAF AZ 61-70 APP STATION STATIOq NA&W YEARS UNCT PAGE 1 0900-1100 MsI" IL. S. T.) T..p.WET &ULD TEMPERATURE DEPRESION (F) TOTAL I TTL "/ 0 1-2 53 -6 I 9...PSYCHROMETRIC SUMMARY P2 AP WEATHER SERVICE/"AC 722730 FT MUACI4UCA/LhSU VLAF AZ 6-0JUL 19 PAGE 1 c90o-11jo WET WULM TUMPERATUItE DEPRESION (P) _____TOTAL...STATIO’ STATION NAME YEARS MO.T. PAGE 1 09S0-11anHO0URS L. S. T.) WET BULB TEMPERATURE DEPRESION (F) TOTAL TOTAL ( (Fl 0 1-2 3.4 5.6 It7.8 10 11112 13

  2. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Sourav, E-mail: sourav.bhattacharjee@wur.nl [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Opstal, Edward J. van; Alink, Gerrit M. [Wageningen University, Division of Toxicology (Netherlands); Marcelis, Antonius T. M.; Zuilhof, Han [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Rietjens, Ivonne M. C. M. [Wageningen University, Division of Toxicology (Netherlands)

    2013-06-15

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size {approx}45 nm) and polystyrene nanoparticles (PSNPs/size {approx}50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  3. Correction of Sampling Errors in Ocean Surface Cross-Sectional Estimates from Nadir-Looking Weather Radar

    Science.gov (United States)

    Caylor, I. Jeff; Meneghini, R.; Miller, L. S.; Heymsfield, G. M.

    1997-01-01

    The return from the ocean surface has a number of uses for airborne meteorological radar. The normalized surface cross section has been used for radar system calibration, estimation of surface winds, and in algorithms for estimating the path-integrated attenuation in rain. However, meteorological radars are normally optimized for observation of distributed targets that fill the resolution volume, and so a point target such as the surface can be poorly sampled, particularly at near-nadir look angles. Sampling the nadir surface return at an insufficient rate results in a negative bias of the estimated cross section. This error is found to be as large as 4 dB using observations from a high-altitude airborne radar. An algorithm for mitigating the error is developed that is based upon the shape of the surface echo and uses the returned signal at the three range gates nearest the peak surface echo.

  4. Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, Yuki, E-mail: ynagao@jaist.ac.jp; Kubo, Takahiro

    2014-12-30

    Graphical abstract: - Highlights: • Proton transport of fully protonated poly(aspartic acid) thin film was investigated. • The thin film structure differed greatly from the partially protonated one. • Proton transport occurs on the surface, not inside of the thin film. • This result contributes to biological transport systems such as bacteriorhodopsin. - Abstract: Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120–670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system.

  5. The weathering of oil after the Deepwater Horizon oil spill: insights from the chemical composition of the oil from the sea surface, salt marshes and sediments

    Science.gov (United States)

    Liu, Zhanfei; Liu, Jiqing; Zhu, Qingzhi; Wu, Wei

    2012-09-01

    The oil released during the Deepwater Horizon (DWH) oil spill may have both short- and long-time impacts on the northern Gulf of Mexico ecosystems. An understanding of how the composition and concentration of the oil are altered by weathering, including chemical, physical and biological processes, is needed to evaluate the oil toxicity and impact on the ecosystem in the northern Gulf of Mexico. This study examined petroleum hydrocarbons in oil mousse collected from the sea surface and salt marshes, and in oil deposited in sediments adjacent to the wellhead after the DWH oil spill. Oil mousses were collected at two stations (OSS and CT, located 130 and 85 km away from the wellhead, respectively) in May 2010, and two sediment samples from stations SG and SC, within 6 km of the wellhead, in May 2011. We also collected oil mousse from salt marshes at Marsh Point (MP), Mississippi, 186 km away from the wellhead in July 2010. In these samples, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, BTEX (collective name of benzene, toluene, ethylbenzene and p-, m-, and o-xylenes), C3-benzenes and trace metals were measured to examine how the oil was altered chemically. The chemical analysis indicates that the oil mousses underwent different degrees of weathering with the pattern of OSS Petroleum hydrocarbon data reveal that the oil deposited in sediments underwent only light to moderate degradation one year after the DWH oil spill, as supported by the presence of short-chained n-alkanes (C10-C 15), BTEX and C 3-benzenes. The weathering of oil in sediment may result from biological degradation and dissolution, evidenced by the preferential loss of mid-chained n-alkanes C16-C 27, lower ratios of n-C 17/Pr and n-C 18/Ph , and preferential loss of PAHs relative to alkylated PAHs.

  6. Ricci Curvature on Polyhedral Surfaces via Optimal Transportation

    Directory of Open Access Journals (Sweden)

    Benoît Loisel

    2014-03-01

    Full Text Available The problem of correctly defining geometric objects, such as the curvature, is a hard one in discrete geometry. In 2009, Ollivier defined a notion of curvature applicable to a wide category of measured metric spaces, in particular to graphs. He named it coarse Ricci curvature because it coincides, up to some given factor, with the classical Ricci curvature, when the space is a smooth manifold. Lin, Lu and Yau and Jost and Liu have used and extended this notion for graphs, giving estimates for the curvature and, hence, the diameter, in terms of the combinatorics. In this paper, we describe a method for computing the coarse Ricci curvature and give sharper results, in the specific, but crucial case of polyhedral surfaces.

  7. Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

    Directory of Open Access Journals (Sweden)

    K. Yi

    2017-07-01

    Full Text Available The response of surface ozone (O3 concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM. Idealized, spatially uniform sea surface temperature (SST anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage

  8. Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

    Science.gov (United States)

    Yi, Kan; Liu, Junfeng; Ban-Weiss, George; Zhang, Jiachen; Tao, Wei; Cheng, Yanli; Tao, Shu

    2017-07-01

    The response of surface ozone (O3) concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM). Idealized, spatially uniform sea surface temperature (SST) anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage between basin-scale SST

  9. GHRSST Level 2P Western Pacific Regional Skin Sea Surface Temperature from the Multifunctional Transport Satellite 1R (MTSAT-1R) (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multi-functional Transport Satellites (MTSAT) are a series of geostationary weather satellites operated by the Japan Meteorological Agency (JMA). MTSAT carries an...

  10. GHRSST Level 2P Western Pacific Regional Skin Sea Surface Temperature from the Multifunctional Transport Satellite 2 (MTSAT-2) (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multi-functional Transport Satellites (MTSAT) are a series of geostationary weather satellites operated by the Japan Meteorological Agency (JMA). MTSAT carries an...

  11. A simple parameterization of the short-wave aerosol optical properties for surface direct and diffuse irradiances assessment in a numerical weather model

    Directory of Open Access Journals (Sweden)

    J. A. Ruiz-Arias

    2014-01-01

    Full Text Available Broadband short-wave (SW surface direct and diffuse irradiances are not typically within the set of output variables produced by numerical weather prediction (NWP models. However, they are being more and more demanded in solar energy applications. A detailed representation of the aerosol optical properties is important to achieve an accurate assessment of these direct and diffuse irradiances. Nonetheless, NWP models typically oversimplify its representation or even neglect its effect. In this work, a flexible method to account for the SW aerosol optical properties in the computation of broadband SW surface direct and diffuse irradiances is presented. It only requires aerosol optical depth at 0.55 μm and the type of predominant aerosol. The rest of parameters needed to consider spectral aerosol extinction, namely, Angström exponent, aerosol single-scattering albedo and aerosol asymmetry factor, are parameterized. The parameterization has been tested in the RRTMG SW scheme of the Weather Research and Forecasting (WRF NWP model. However, it can be adapted to any other SW radiative transfer band model. It has been verified against a control experiment along five radiometric stations in the contiguous US. The control experiment consisted of a clear-sky evaluation of the RRTMG solar radiation estimates obtained in WRF when RRTMG is driven with ground-observed aerosol optical properties. Overall, the verification has shown very satisfactory results for both broadband SW surface direct and diffuse irradiances. It has proven effective to significantly reduce the prediction error and constraint the seasonal bias in clear-sky conditions to within the typical observational error in well-maintained radiometers.

  12. A New Concept to Transport a Droplet on Horizontal Hydrophilic/Hydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook [Kookmin Univ., Seoul (Korea, Republic of)

    2014-03-15

    A fluid transport technique is a key issue for the development of microfluidic systems. In this paper, a new concept for transporting a droplet without external power sources is proposed and verified numerically. The proposed device is a heterogeneous surface which has both hydrophilic and hydrophobic horizontal surfaces. The numerical simulation to demonstrate the new concept is conducted by an in-house solution code (PowerCFD) which employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method (CICSAM) in a volume of fluid (VOF) scheme for phase interface capturing. It is found that the proposed concept for droplet transport shows superior performance for droplet transport in microfluidic systems.

  13. Selective detection of Fe and Mn species at mineral surfaces in weathered granite by conversion electron yield X-ray absorption fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Itai, Takaaki [Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)], E-mail: itai-epss@hiroshima-u.ac.jp; Takahashi, Yoshio [Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Uruga, Tomoya; Tanida, Hajime [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Iida, Atsuo [Photon Factory, National Laboratory for High Energy Physics, O-ho, Tsukuba, Ibaraki 305 (Japan)

    2008-09-15

    A new method for the speciation of Fe and Mn at mineral surfaces is proposed using X-ray absorption fine structure in conversion electron yield mode (CEY-XAFS). This method generally reflects information on the species at the sub-{mu}m scale from the particle surface due to the limited escape depth of the inelastic Auger electron. The surface sensitivity of this method was assessed by experiments on two samples of granite showing different degrees of weathering. The XANES spectra of the Fe-K and Mn-K edge clearly gave different information for CEY and fluorescence (FL) modes. These XANES spectra of Fe and Mn show a good fit upon application of least-squares fitting using ferrihydrite/MnO{sub 2} and biotite as the end members. The XANES spectra collected by CEY mode provided more selective information on the secondary phases which are probably present at the mineral surfaces. In particular, CEY-XANES spectra of Mn indicated the presence of Mn oxide in unweathered granite despite a very small contribution of Mn oxide being indicated by FL-XANES and selective chemical-extraction analyses. Manganese oxide could not be detected by micro-beam XANES (beam size: 5 x 5 {mu}m{sup 2}) in unweathered granite, suggesting that Mn oxide thinly and ubiquitously coats mineral surface at a sub-{mu}m scale. This information is important, since Mn oxide can be the host for various trace elements. CEY-XAFS can prove to be a powerful tool as a highly sensitive surface speciation method. Combination of CEY and FL-XAFS will help identify minor phases that form at mineral surfaces, but identification of Fe and Mn oxides at mineral surfaces is critical to understand the migration of trace elements in water-rock interaction.

  14. Applications of asymmetric nanotextured parylene surface using its wetting and transport properties

    Science.gov (United States)

    Sekeroglu, Koray

    In this thesis, basic digital fluidics devices were introduced using polymeric nanorods (nano-PPX) inspired from nature. Natural inspiration ignited this research by observing butterfly wings, water strider legs, rye grass leaves, and their asymmetric functions. Nano-PPX rods, manufactured by an oblique angle polymerization (OAP) method, are asymmetrically aligned structures that have unidirectional wetting properties. Nano-PPX demonstrates similar functions to the directional textured surfaces of animals and plants in terms of wetting, adhesion, and transport. The water pin-release mechanism on the asymmetric nano-PPX surface with adhesion function provides a great transport property. How the asymmetry causes transport is discussed in terms of hysteresis and interface contact of water droplets. In this study, the transport property of nano-PPX rods is used to guide droplets as well as transporting cargo such as microgels. With the addition of tracks on the nano-PPX rods, the surfaces were transformed into basic digital fluidics devices. The track-assisted nano-PPX has been employed to applications (i.e. sorting, mixing, and carrying cargo particles). Thus, digital fluidics devices fabricated on nano-PPX surface is a promising pathway to assemble microgels in the field of bioengineering. The characterization of the nano textured surface was completed using methods such as Scanning Electron Microscopy, Atomic Force Microscopy, Contact Angle Goniometry, and Fourier Transform Infra-Red Spectroscopy. These methods helped to understand the physical and chemical properties of nano-PPX. Parameters such as advancing and receding contact angles, nanorod tilt angle, and critical drop volumes were utilized to investigate the anisotropic wetting properties of nano-PPX surface. This investigation explained the directional wetting behavior of the surface as well as approaching new design parameters for adjusting surface properties. The nanorod tilt angle was a key parameter

  15. Climatic variability of near-surface turbulent kinetic energy over the United States: implications for fire-weather predications

    Science.gov (United States)

    Warren E. Heilman; Xindi. Bain

    2013-01-01

    Recent research suggests that high levels of ambient near-surface atmospheric turbulence are often associated with rapid and sometimes erratic wildland fire spread that may eventually lead to large burn areas. Previous research has also examined the feasibility of using near-surface atmospheric turbulent kinetic energy (TKEs) alone or in...

  16. Effects of trans-Eurasian transport of air pollutants on surface ozone concentrations over Western China

    Science.gov (United States)

    Li, Xiaoyuan; Liu, Junfeng; Mauzerall, Denise L.; Emmons, Louisa K.; Walters, Stacy; Horowitz, Larry W.; Tao, Shu

    2014-11-01

    Due to a lack of industrialization in Western China, surface air there was, until recently, believed to be relatively unpolluted. However, recent measurements and modeling studies have found high levels of ozone (O3) there. Based on the state-of-the-science global chemical transport model MOZART-4, we identify the origin, pathway, and mechanism of trans-Eurasian transport of air pollutants to Western China in 2000. MOZART-4 generally simulates well the observed surface O3 over inland areas of China. Simulations find surface ozone concentrations over Western China on average to be about 10 ppbv higher than Eastern China. Using sensitivity studies, we find that anthropogenic emissions from all Eurasian regions except China contribute 10-15 ppbv surface O3 over Western China, superimposed upon a 35-40 ppbv natural background. Transport from European anthropogenic sources to Northwestern China results in 2-6 ppbv O3 enhancements in spring and summer. Indian anthropogenic sources strongly influence O3 over the Tibetan Plateau during the summer monsoon. Transport of O3 originating from emissions in the Middle East occasionally reach Western China and increase surface ozone there by about 1-4 ppbv. These influences are of similar magnitude as trans-Pacific and transatlantic transport of O3 and its precursors, indicating the significance of trans-Eurasian ozone transport in hemispheric transport of air pollution. Our study further indicates that mitigation of anthropogenic emissions from Europe, the Indian subcontinent, and the Middle East could benefit public health and agricultural productivity in Western China.

  17. Effects of trans-Eurasian transport of anthropogenic pollutants on surface ozone concentrations over China

    Science.gov (United States)

    Liu, J.; Li, X.; Mauzerall, D. L.; Emmons, L. K.; Horowitz, L. W.; Guo, Y.; Tao, S.

    2015-12-01

    Due to a lack of industrialization in Western China, surface air there was, until recently, believed to be relatively unpolluted. However, recent measurements and modeling studies have found high levels of ozone (O3) there. Based on the state-of-the-science global chemical transport model MOZART-4, we identify the origin, pathway, and mechanism of trans-Eurasian transport of air pollutants to Western China in 2000. MOZART-4 generally simulates well the observed surface O3 over inland areas of China. Simulations find surface ozone concentrations over Western China on average to be about 10 ppbv higher than Eastern China. Using sensitivity studies as well as a fully-tagged approach, we find that anthropogenic emissions from all Eurasian regions except China contribute 10-15 ppbv surface O3 over Western China, superimposed upon a 35-40 ppbv natural background. Transport from European anthropogenic sources to Northwestern China results in 2-6 ppbv O3 enhancements in spring and summer. Indian anthropogenic sources strongly influence O3 over the Tibetan Plateau during the summer monsoon. Transport of O3 originating from emissions in the Middle East occasionally reach Western China and increase surface ozone there by about 1-4 ppbv. These influences are of similar magnitude as trans-Pacific and transatlantic transport of O3 and its precursors, indicating the significance of trans-Eurasian ozone transport in hemispheric transport of air pollution. Our study further indicates that mitigation of anthropogenic emissions from Europe, the Indian subcontinent, and the Middle East could benefit public health and agricultural productivity in Western China.

  18. Light-Driven Transport of a Liquid Marble with and against Surface Flows.

    Science.gov (United States)

    Kavokine, Nikita; Anyfantakis, Manos; Morel, Mathieu; Rudiuk, Sergii; Bickel, Thomas; Baigl, Damien

    2016-09-01

    Liquid marbles, that is, liquid drops coated by a hydrophobic powder, do not wet any solid or liquid substrate, making their transport and manipulation both highly desirable and challenging. Herein, we describe the light-driven transport of floating liquid marbles and emphasize a surprising motion behavior. Liquid marbles are deposited on a water solution containing photosensitive surfactants. Irradiation of the solution generates photoreversible Marangoni flows that transport the liquid marbles toward UV light and away from blue light when the thickness of the liquid substrate is large enough (Marangoni regime). Below a critical thickness, the liquid marbles move in the opposite direction to that of the surface flow at a speed increasing with decreasing liquid thickness (anti-Marangoni). We demonstrate that the anti-Marangoni motion is driven by the free surface deformation, which propels the non-wetting marble against the surface flow. We call this behavior "slide effect".

  19. Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

    Science.gov (United States)

    Nagao, Yuki; Kubo, Takahiro

    2014-12-01

    Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120-670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system.

  20. Continuous directional water transport on the peristome surface of Nepenthes alata

    Science.gov (United States)

    Chen, Huawei; Zhang, Pengfei; Zhang, Liwen; Liu, Hongliang; Jiang, Ying; Zhang, Deyuan; Han, Zhiwu; Jiang, Lei

    2016-04-01

    Numerous natural systems contain surfaces or threads that enable directional water transport. This behaviour is usually ascribed to hierarchical structural features at the microscale and nanoscale, with gradients in surface energy and gradients in Laplace pressure thought to be the main driving forces. Here we study the prey-trapping pitcher organs of the carnivorous plant Nepenthes alata. We find that continuous, directional water transport occurs on the surface of the ‘peristome’—the rim of the pitcher—because of its multiscale structure, which optimizes and enhances capillary rise in the transport direction, and prevents backflow by pinning in place any water front that is moving in the reverse direction. This results not only in unidirectional flow despite the absence of any surface-energy gradient, but also in a transport speed that is much higher than previously thought. We anticipate that the basic ‘design’ principles underlying this behaviour could be used to develop artificial fluid-transport systems with practical applications.

  1. Fort Simpson, Northwest Territories, Canada. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1972-01-25

    5s7 4.1 6.3 * .1 17,’ Wp SSE 1.6 1,3 2.3 .3 .0 _,.__6,2 S , a4 o3 4,_ 2 SSW .3 . .1 .4 3.6 SIN ,4 ,2 *2 @1 .7I 5,9 wSW ,i . 2 1, Q .1 6 5,4 w o...7ESE I~ lE 4.3 . 7’,.4 , SE 3el 7 a ’W 1.5 17.7 7 SSE ’, 1.0 .9 c3 -;-7 o s ,6 1.3 1.2 ___ _2T SIN 26 ,4 s,3 1’,4 4,5 WSW #1 .4 .1 .3 _ _.9 w *,1 .1 l...3766 SFP SA,- SITAn SAt& V... N0M1m ALL WEATHER 0000-0200 CLASS NOCUSS L.S.t.I SPEED MEAN (KNTS) 3 4. 6 7- 10 j 11 - 16 17. 21 22.27 28-33 34.40 41 .47

  2. Tunable Surface Hydrophobicity and Fluid Transport through Nanoporous Membranes

    Science.gov (United States)

    Ostrowski, Joseph H. J.

    There are more than three billion people across the globe that struggle to obtain clean drinkable water. One of the most promising avenues for generating potable water is through reverse osmosis and nanofiltration. Both solutions require a semipermeable membrane that prohibits passage of unwanted solute particles but allows passage of the solvent. Atomically thin two-dimensional membranes based on porous graphene show great promise as semipermeable materials, but modeling fluid flow on length scales between the microscopic (nanometer and smaller) and macroscopic (micron and larger) regimes presents formidable challenges. This thesis explores both equilibrium and nonequilibrium aspects of this problem and develops new methodology for simulating systems away from thermal equilibrium. First, we hypothesize that there is a wetting penalty for water as it tries to breach a sheet of graphene that should be naturally hydrophobic. By using equilibrium molecular dynamics simulations, we show that the hydrophobicity depends sensitively on the degree of electrical doping, offering an opportunity to tune the hydrophobic effect of graphene using small amounts of doping. The wetting contact angle, a measure of hydrophobicity, changes dramatically with the voltage applied to single layer graphene. We find that the sensitivity of the hydrophobic effect to voltage depends not on hydrogen bonding motifs at the interface between graphene and water, but instead on a phenomenon known as electrowetting. The theory of electrowetting predicts that the difference in surface tensions that defines the contact angle is quartic in the voltage, rather than quadratic, as it would be in bilayer graphene or in a two-dimensional metal. To explore the nonequilibrium aspects of fluid passage through atomically thin membranes, we developed a molecular dynamics methodology for simulating fluid flow at constant flux based on Gauss's principle of least constraint. This method develops microscopic

  3. Corresponding-states principle and its practice thermodynamic, transport and surface properties of fluids

    CERN Document Server

    Xiang, Hong Wei

    2005-01-01

    The corresponding-states principle helps the understanding and calculating of thermodynamic, transport, and surface properties of substances in various states, required by our modern lifestyle. The Corresponding-States Principle and its Practice: Thermodynamic, Transport and Surface Properties of Fluids describes the origins and applications of the principle from a universal point of view with comparisons to experimental data where possible. It uses the universal theory to explain present theories. Emphasis is on the properties of pure systems, and the corresponding-states theory can also be e

  4. Weather Derivatives – Origin, Types and Application

    Directory of Open Access Journals (Sweden)

    Piotr Binkowski

    2008-03-01

    Full Text Available The number of companies that are exposed to the revenues loss risk caused by weather variability is still increasing. The businesses that are mostly exposed to weather risk are following: energy, agriculture, constructions and transport. That situation has initiated dynamic growth of weather derivatives markets as well as the awareness of the weather risk among the market participants. Presently, the weather derivatives markets evaluate rapidly in all the mature economies: USA, Asia and Europe. Constructing weather derivatives relies on qu- antifying climate factors in the form of indexes, what is quite simple task, more difficultly can be gathering precise historical data of required climate factors. Taking into consideration so far development of derivatives ñ especially the financial derivatives based on different types of indexes ñ financial market has at disposal wide range of different types of proved derivatives (futures, forward, options, swaps, which can be successfully utilised on the weather-driven markets both for hedging weather risk and speculating.

  5. Coupling convectively driven atmospheric circulation to surface rotation: Evidence for active methane weather in the observed spin rate drift of Titan

    CERN Document Server

    Mitchell, Jonathan L

    2008-01-01

    A large drift in the rotation rate of Titan observed by Cassini provided the first evidence of a subsurface ocean isolating the massive core from the icy crust. Seasonal exchange of angular momentum between the surface and atmosphere accounts for the magnitude of the effect, but observations lag the expected signal by a few years. We argue this time lag is due to the presence of an active methane weather cycle in the atmosphere. An analytic model of the seasonal cycle of atmospheric angular momentum is developed and compared to time-dependent simulations of Titan's atmosphere with and without methane thermodynamics. The disappearance of clouds at the summer pole suggests the drift rate has already switched direction, signaling the change in season from solstice to equinox.

  6. Stormy Weather

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Inspired by the deep abyss of the unknown; a constant source for investigation and discovery, heating and destruction, all simultaneously. Beneath the deep darkness, millions of species vibrantly thrive in another universe wholly untouched by human hands, though affected by their choices. The weathered pieces and people associated with seaside villages, the deep wrinkles that tell a story of one's life and experiences like

  7. Road Weather and Connected Vehicles

    Science.gov (United States)

    Pisano, P.; Boyce, B. C.

    2015-12-01

    On average, there are over 5.8 M vehicle crashes each year of which 23% are weather-related. Weather-related crashes are defined as those crashes that occur in adverse weather or on slick pavement. The vast majority of weather-related crashes happen on wet pavement (74%) and during rainfall (46%). Connected vehicle technologies hold the promise to transform road-weather management by providing improved road weather data in real time with greater temporal and geographic accuracy. This will dramatically expand the amount of data that can be used to assess, forecast, and address the impacts that weather has on roads, vehicles, and travelers. The use of vehicle-based measurements of the road and surrounding atmosphere with other, more traditional weather data sources, and create road and atmospheric hazard products for a variety of users. The broad availability of road weather data from mobile sources will vastly improve the ability to detect and forecast weather and road conditions, and will provide the capability to manage road-weather response on specific roadway links. The RWMP is currently demonstrating how weather, road conditions, and related vehicle data can be used for decision making through an innovative Integrated Mobile Observations project. FHWA is partnering with 3 DOTs (MN, MI, & NV) to pilot these applications. One is a mobile alerts application called the Motorists Advisories and Warnings (MAW) and a maintenance decision support application. These applications blend traditional weather information (e.g., radar, surface stations) with mobile vehicle data (e.g., temperature, brake status, wiper status) to determine current weather conditions. These weather conditions, and other road-travel-relevant information, are provided to users via web and phone applications. The MAW provides nowcasts and short-term forecasts out to 24 hours while the EMDSS application can provide forecasts up to 72 hours in advance. The three DOTs have placed readers and external

  8. A simple approach to fabricate the rose petal-like hierarchical surfaces for droplet transportation

    Science.gov (United States)

    Yuan, Chao; Huang, Mengyu; Yu, Xingjian; Ma, Yupu; Luo, Xiaobing

    2016-11-01

    Precise transportation of liquid microdroplets is a great challenge in the microfluidic field. A sticky superhydrophobic surface with a high static contact angle (CA) and a large contact angle hysteresis (CAH) is recognized as the favorable tool to deal with the challenging job. Some approaches have been proposed to fabricate such surface, such as mimicing the dual-scale hierarchical structure of a natural material, like rose petal. However, the available approaches normally require multiple processing steps or are carried out with great expense. In this study, we report a straightforward and inexpensive method for fabricating the sticky superhydrophobic surfaces. The fabrication relies on electroless galvanic deposition to coat the copper substrates with a textured layer of silver. The whole fabrication process is carried out under ambient conditions by using conventional laboratory materials and equipments, and generally take less than 15 min. Despite the simplicity of this fabrication method, the rose petal-like hierarchical structures and the corresponding sticky superhydrophobic wetting properties were well achieved on the artificial surfaces. For instance, the surface with a deposition time of 10 s exhibits the superhydrophobity with a CA of 151.5°, and the effective stickiness with a CAH of 56.5°. The prepared sticky superhydrophobic surfaces are finally shown in the application of droplet transportation, in which the surface acts as a mechanical hand to grasp and transport the water droplet.

  9. Probing the electronic transport on the reconstructed Au/Ge(001 surface

    Directory of Open Access Journals (Sweden)

    Franciszek Krok

    2014-09-01

    Full Text Available By using scanning tunnelling potentiometry we characterized the lateral variation of the electrochemical potential µec on the gold-induced Ge(001-c(8 × 2-Au surface reconstruction while a lateral current flows through the sample. On the reconstruction and across domain boundaries we find that µec shows a constant gradient as a function of the position between the contacts. In addition, nanoscale Au clusters on the surface do not show an electronic coupling to the gold-induced surface reconstruction. In combination with high resolution scanning electron microscopy and transmission electron microscopy, we conclude that an additional transport channel buried about 2 nm underneath the surface represents a major transport channel for electrons.

  10. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes

    Energy Technology Data Exchange (ETDEWEB)

    He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

    2011-08-01

    The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

  11. Weathering of the New Albany Shale, Kentucky: II. Redistribution of minor and trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Tuttle, Michele L.W., E-mail: mtuttle@usgs.gov [US Geological Survey, MS 964D, Box 25046, Denver, CO 80215 (United States); Breit, George N.; Goldhaber, Martin B. [US Geological Survey, MS 964D, Box 25046, Denver, CO 80215 (United States)

    2009-08-15

    During weathering, elements enriched in black shale are dispersed in the environment by aqueous and mechanical transport. Here a unique evaluation of the differential release, transport, and fate of Fe and 15 trace elements during progressive weathering of the Devonian New Albany Shale in Kentucky is presented. Results of chemical analyses along a weathering profile (unweathered through progressively weathered shale to soil) describe the chemically distinct pathways of the trace elements and the rate that elements are transferred into the broader, local environment. Trace elements enriched in the unweathered shale are in massive or framboidal pyrite, minor sphalerite, CuS and NiS phases, organic matter and clay minerals. These phases are subject to varying degrees and rates of alteration along the profile. Cadmium, Co, Mn, Ni, and Zn are removed from weathered shale during sulfide-mineral oxidation and transported primarily in aqueous solution. The aqueous fluxes for these trace elements range from 0.1 g/ha/a (Cd) to 44 g/ha/a (Mn). When hydrologic and climatic conditions are favorable, solutions seep to surface exposures, evaporate, and form Fe-sulfate efflorescent salts rich in these elements. Elements that remain dissolved in the low pH (<4) streams and groundwater draining New Albany Shale watersheds become fixed by reactions that increase pH. Neutralization of the weathering solution in local streams results in elements being adsorbed and precipitated onto sediment surfaces, resulting in trace element anomalies. Other elements are strongly adsorbed or structurally bound to solid phases during weathering. Copper and U initially are concentrated in weathering solutions, but become fixed to modern plant litter in soil formed on New Albany Shale. Molybdenum, Pb, Sb, and Se are released from sulfide minerals and organic matter by oxidation and accumulate in Fe-oxyhydroxide clay coatings that concentrate in surface soil during illuviation. Chromium, Ti, and V are

  12. Weathering of the New Albany Shale, Kentucky: II. Redistribution of minor and trace elements

    Science.gov (United States)

    Tuttle, M.L.W.; Breit, G.N.; Goldhaber, M.B.

    2009-01-01

    During weathering, elements enriched in black shale are dispersed in the environment by aqueous and mechanical transport. Here a unique evaluation of the differential release, transport, and fate of Fe and 15 trace elements during progressive weathering of the Devonian New Albany Shale in Kentucky is presented. Results of chemical analyses along a weathering profile (unweathered through progressively weathered shale to soil) describe the chemically distinct pathways of the trace elements and the rate that elements are transferred into the broader, local environment. Trace elements enriched in the unweathered shale are in massive or framboidal pyrite, minor sphalerite, CuS and NiS phases, organic matter and clay minerals. These phases are subject to varying degrees and rates of alteration along the profile. Cadmium, Co, Mn, Ni, and Zn are removed from weathered shale during sulfide-mineral oxidation and transported primarily in aqueous solution. The aqueous fluxes for these trace elements range from 0.1 g/ha/a (Cd) to 44 g/ha/a (Mn). When hydrologic and climatic conditions are favorable, solutions seep to surface exposures, evaporate, and form Fe-sulfate efflorescent salts rich in these elements. Elements that remain dissolved in the low pH (reactions that increase pH. Neutralization of the weathering solution in local streams results in elements being adsorbed and precipitated onto sediment surfaces, resulting in trace element anomalies. Other elements are strongly adsorbed or structurally bound to solid phases during weathering. Copper and U initially are concentrated in weathering solutions, but become fixed to modern plant litter in soil formed on New Albany Shale. Molybdenum, Pb, Sb, and Se are released from sulfide minerals and organic matter by oxidation and accumulate in Fe-oxyhydroxide clay coatings that concentrate in surface soil during illuviation. Chromium, Ti, and V are strongly correlated with clay abundance and considered to be in the structure of

  13. Formulation Effects and the Off-target Transport of Pyrethroid Insecticides from Urban Hard Surfaces

    OpenAIRE

    2010-01-01

    Controlled rainfall experiments utilizing drop forming rainfall simulators were conducted to study various factors contributing to off-target transport of off-the-shelf formulated pyrethroid insecticides from concrete surfaces. Factors evaluated included active ingredient, product formulation, time between application and rainfall (set time), and rainfall intensity. As much as 60% and as little as 0.8% of pyrethroid applied could be recovered in surface runoff depending primarily on product f...

  14. PETROCHEMISTRY AND MINERALOGY EVIDENCES FOR THE WEATHERING PROCESS OF THE WEATHERING PITS ON ROCK SURFACES OF MOUNTAIN LAOSHAN,CHINA%崂山山顶风化坑化学风化过程的岩石化学与矿物学证据

    Institute of Scientific and Technical Information of China (English)

    王为; 周尚哲; 李炳元; 林志海; 刘志鹏; 黄日辉; 赖宜讯; 陈科景

    2012-01-01

    After the first field trip in July of 2010,the authors made a second field trip in May of 2011 to investigate the weathering pits on the top of Mountain Laoshan, which is composed of Mesozoic granite with its highest peak 1132. 7meters above sea level and located on the shore of the Yellow Sea, China. The conclusion of the first investigation is that the so-called glacial potholes in Mountain Laoshan are nothing but weathering pits as are generally found in the other granite areas around the world and then the pits on the rock surface of Mountain Laoshan are not originated from glaciers. In this paper, the evidence collected in this field investigation for the weathering origin of the pits is discussed.The detritus in the weathering pits and the surface rock outside the pits were taken from 7 weathering pits ,4 of which at Laoding,the top of the mountain about l000m's high, and 3 in Hualou area, northwest of Laoding with elevations of 280 ~340m. X-Ray fluorescence(XRF) and X-ray diffraction ( XRD ) methods are used to measure the type and the amount of minerals and chemical elements of the rock samples. Based on the result of XDF and XDR, the samples' chemical index CIA, weathering ratios and element transformation ratio were calculated. The weathering process of the pits was analyzed and discussed in the following aspects: 1) The relation of the chemical weathering to the mineral weathering of the pit detritus; 2)Chemical element transferring between the pit detritus and the surface rock; 3)The different weathering intensity of the pits and the surface rock of Mountain Laoshan and its cause. The result of the study shows that: l)The ratio between quartz and feldspar of the detritus is higher than those of the surface rock, indicating the feldspar being degenerated by weathering while the quartz remaining the same in the pits; 2)The weathered feldspars in the pit are mainly perthite and potassium feldspars owing to a lack of plagioclase in their original rocks; 3

  15. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2017-01-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  16. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2016-07-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  17. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2016-07-21

    We evaluate the sensitivity of simulated turbine-height winds to 26 parameters applied in a planetary boundary layer (PBL) scheme and a surface layer scheme of the Weather Research and Forecasting (WRF) model over an area of complex terrain during the Columbia Basin Wind Energy Study. An efficient sampling algorithm and a generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of modeled turbine-height winds. The results indicate that most of the variability in the ensemble simulations is contributed by parameters related to the dissipation of the turbulence kinetic energy (TKE), Prandtl number, turbulence length scales, surface roughness, and the von Kármán constant. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability. The parameter associated with the TKE dissipation rate is found to be the most important one, and a larger dissipation rate can produce larger hub-height winds. A larger Prandtl number results in weaker nighttime winds. Increasing surface roughness reduces the frequencies of both extremely weak and strong winds, implying a reduction in the variability of the wind speed. All of the above parameters can significantly affect the vertical profiles of wind speed, the altitude of the low-level jet and the magnitude of the wind shear strength. The wind direction is found to be modulated by the same subset of influential parameters. Remainder of abstract is in attachment.

  18. The role of weathering in the formation of bedrock valleys on Earth and Mars: A numerical modeling investigation

    Science.gov (United States)

    Pelletier, Jon D.; Baker, Victor R.

    2011-11-01

    Numerical models of bedrock valley development generally do not include weathering explicitly. Nevertheless, weathering is an essential process that acts in concert with the transport of loose debris by seepage and runoff to form many bedrock valleys. Here we propose a numerical model for bedrock valley development that explicitly distinguishes weathering and the transport of loose debris and is capable of forming bedrock valleys similar to those observed in nature. In the model, weathering rates are assumed to increase with increasing water availability, a relationship that data suggest likely applies in many water-limited environments. We compare and contrast the model results for cases in which weathering is the result of runoff-induced infiltration versus cases in which it is the result of seepage- or subsurface-driven flow. The surface flow-driven version of our model represents an alternative to the stream-power model that explicitly shows how rates of both weathering and the transport of loose debris are related to topography or water flow. The subsurface flow-driven version of our model can be solved analytically using the linearized Boussinesq approximation. In such cases the model predicts theater-headed valleys that are parabolic in planform, a prediction broadly consistent with the observed shapes of theater-headed bedrock valleys on Mars that have been attributed to a combination of seepage weathering and episodic removal of weathered debris by runoff, seepage, and/or spring discharge.

  19. Patterned gradient surface for spontaneous droplet transportation and water collection: simulation and experiment

    Science.gov (United States)

    Tan, Xianhua; Zhu, Yiying; Shi, Tielin; Tang, Zirong; Liao, Guanglan

    2016-11-01

    We demonstrate spontaneous droplet transportation and water collection on wedge-shaped gradient surfaces consisting of alternating hydrophilic and hydrophobic regions. Droplets on the surfaces are modeled and simulated to analyze the Gibbs free energy and free energy gradient distributions. Big half-apex angle and great wettability difference result in considerable free energy gradient, corresponding to large driving force for spontaneous droplet transportation, thus causing the droplets to move towards the open end of the wedge-shaped hydrophilic regions, where the Gibbs free energy is low. Gradient surfaces are then fabricated and tested. Filmwise condensation begins on the hydrophilic regions, forming wedge-shaped tracks for water collection. Dropwise condensation occurs on the hydrophobic regions, where the droplet size distribution and departure diameters are controlled by the width of the regions. Condensate water from both the hydrophilic and hydrophobic regions are collected directionally to the open end of the wedge-shaped hydrophilic regions, agreeing with the simulations. Directional droplet transport and controllable departure diameters make the branched gradient surfaces more efficient than smooth surfaces for water collection, which proves that gradient surfaces are potential in water collection, microfluidic devices, anti-fogging and self-cleaning.

  20. Mass Transport in a Thin Layer of Bi-Viscous Mud Under Surface Waves

    Institute of Scientific and Technical Information of China (English)

    NG Chiu-on; FU Sau-chung; BAI Yu-chuan(白玉川)

    2002-01-01

    The mass transport in a thin layer of non-Newtonian bed mud under surface waves is examined with a two-fluidStokes boundary layer model. The mud is assumed to be a bi-viscous fluid, which tends to resist motion for small-appliedstresses, but flows readily when the yield stress is exceeded. Asymptotic expansions suitable for shallow fluid layers areapplied, and the second-order solutions for the mass transport induced by surface progressive waves are obtained numeri-cally. It is found that the stronger the non-Newtonian behavior of the mud, the more pronounced intermittency of theflow. Consequently, the mass transport velocity is diminished in magnitude, and can even become negative (i. e., oppo-site to wave propagation) for a certain range of yield stress.

  1. Ambipolar surface state transport in nonmetallic stoichiometric Bi2Se3 crystals

    Science.gov (United States)

    Syers, Paul; Paglione, Johnpierre

    2017-01-01

    Achieving true bulk insulating behavior in Bi2Se3 , the archetypal topological insulator with a simplistic one-band electronic structure and sizable band gap, has been prohibited by a well-known self-doping effect caused by selenium vacancies, whose extra electrons shift the chemical potential into the bulk conduction band. We report a synthesis method for achieving stoichiometric Bi2Se3 crystals that exhibit nonmetallic behavior in electrical transport down to low temperatures. Hall-effect measurements indicate the presence of both electron- and holelike carriers, with the latter identified with surface state conduction and the achievement of ambipolar transport in bulk Bi2Se3 crystals without gating techniques. With carrier mobilities surpassing the highest values yet reported for topological surface states in this material, the achievement of ambipolar transport via upward band bending is found to provide a key method to advancing the potential of this material for future study and applications.

  2. Mass transport in a thin layer of power-law mud under surface waves

    Science.gov (United States)

    Liu, Jie; Bai, Yuchuan; Xu, Dong

    2017-02-01

    The mass transport velocity in a two-layer system is studied theoretically. The wave motion is driven by a periodic pressure load on the free water surface, and mud in the lower layer is described by a power-law rheological model. Perturbation analysis is performed to the second order to find the mean Eulerian velocity. A numerical iteration method is employed to solve the non-linear governing equation at the leading order. The influence of rheological properties on fluid motion characteristics including the flow field, the surface displacement, the mass transport velocity, and the net discharge rates are investigated based on theoretical results. Theoretical analysis shows that under the action of interfacial shearing, a recirculation structure may appear near the interface in the upper water layer. A higher mass transport velocity at the interface does not necessarily mean a higher discharge rate for a pseudo-plastic fluid mud.

  3. Nonadiabaticity and single-electron transport driven by surface acoustic waves

    DEFF Research Database (Denmark)

    Flensberg, Karsten; Niu, Q.; Pustilnik, M.

    1999-01-01

    Single-electron transport driven by surface acoustic waves (SAW) through a narrow constriction, formed in a two-dimensional electron gas, is studied theoretically. Due to long-range Coulomb interaction, the tunneling coupling between the electron gas and the moving minimum of the SAW...

  4. Quantum transport and two-parameter scaling at the surface of a weak topological insulator.

    Science.gov (United States)

    Mong, Roger S K; Bardarson, Jens H; Moore, Joel E

    2012-02-17

    Weak topological insulators have an even number of Dirac cones in their surface spectrum and are thought to be unstable to disorder, which leads to an insulating surface. Here we argue that the presence of disorder alone will not localize the surface states; rather, the presence of a time-reversal symmetric mass term is required for localization. Through numerical simulations, we show that in the absence of the mass term the surface always flow to a stable metallic phase and the conductivity obeys a one-parameter scaling relation, just as in the case of a strong topological insulator surface. With the inclusion of the mass, the transport properties of the surface of a weak topological insulator follow a two-parameter scaling form.

  5. Reliable transport through a microfabricated X-junction surface-electrode ion trap

    Science.gov (United States)

    Wright, Kenneth; Amini, Jason M.; Faircloth, Daniel L.; Volin, Curtis; Doret, S. Charles; Hayden, Harley; Pai, C.-S.; Landgren, David W.; Denison, Douglas; Killian, Tyler; Slusher, Richart E.; Harter, Alexa W.

    2013-03-01

    We report the design, fabrication and characterization of a microfabricated surface-electrode ion trap that supports controlled transport through the two-dimensional intersection of linear trapping zones arranged in a 90° cross. The trap is fabricated with very large scalable integration techniques which are compatible with scaling to a large quantum information processor. The shape of the radio-frequency electrodes is optimized with a genetic algorithm to reduce axial pseudopotential barriers and minimize ion heating during transport. Seventy-eight independent dc control electrodes enable fine control of the trapping potentials. We demonstrate reliable ion transport between junction legs and determine the rate of ion loss due to transport. Doppler-cooled ions survive more than 105 round-trip transits between junction legs without loss and more than 65 consecutive round trips without laser cooling.

  6. Heating and ion transport in a Y-junction surface-electrode trap

    CERN Document Server

    Shu, G; Volin, C; Buikema, A; Nichols, C S; Stick, D; Brown, Kenneth R

    2014-01-01

    We measure ion heating following transport throughout a Y-junction surface-electrode ion trap. By carefully selecting the trap voltage update rate during adiabatic transport along a trap arm, we observe minimal heating relative to the anomalous heating background. Transport through the junction results in an induced heating between 37 and 150 quanta in the axial direction per traverse. To reliably measure heating in this range, we compare the experimental sideband envelope, including up to fourth-order sidebands, to a theoretical model. The sideband envelope method allows us to cover the intermediate heating range inaccessible to the first-order sideband and Doppler recooling methods. We conclude that quantum information processing in this ion trap will likely require sympathetic cooling in order to support high fidelity gates after junction transport.

  7. Soil, snow, weather, and sub-surface storage data from a mountain catchment in the rain–snow transition zone

    OpenAIRE

    P. R. Kormos; Marks, D.; Williams, C J; H. P. Marshall; P. Aishlin; D. G. Chandler; J. P. McNamara

    2014-01-01

    A comprehensive hydroclimatic data set is presented for the 2011 water year to improve understanding of hydrologic processes in the rain–snow transition zone. This type of data set is extremely rare in scientific literature because of the quality and quantity of soil depth, soil texture, soil moisture, and soil temperature data. Standard meteorological and snow cover data for the entire 2011 water year are included, which include several rain-on-snow (ROS) events. Surface so...

  8. Langley AFB, Newport News, Virginia. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1979-06-01

    i1 1 "+ ’I"+ " *+ +" ENVI-77E 74 4, +, + ~ P CATON C UTER +"+,, :+ PARTO SURFACE WINDS , jr..,+ + -, + +"C reenedi tispatar vriu ta.ltins...frequency distribution of wet-bulb ) depression in 17 classes spread ho izontally; by 2-degree intervals of dry-bulb temperature spread vertically ...humidity and total number of observations in two tables. a. Table 1 is prepared by month and annual, all years combined, with montb being the vertical

  9. Microfour-point probe for studying electronic transport through surface states

    DEFF Research Database (Denmark)

    Petersen, Christian Leth; Grey, Francois; Shiraki, I.

    2000-01-01

    Microfour-point probes integrated on silicon chips have been fabricated with probe spacings in the range 4-60 mum. They provide a simple robust device for electrical transport measurements at surfaces, bridging the gap between conventional macroscopic four-point probes and scanning tunneling...... microscopy. Measurements on Si(111) surfaces in ultrahigh vacuum reveal that the Si(111)-root 3x root3-Ag structure induced by a monolayer of Ag atoms has a four-point resistance two orders of magnitude lower than that of the Si(111)-7x7 clean surface. We attribute this remarkable difference to direct...

  10. Quantum transport in the surface states of epitaxial Bi(111) thin films

    Science.gov (United States)

    Zhu, Kai; Wu, Lin; Gong, Xinxin; Xiao, Shunhao; Jin, Xiaofeng

    2016-09-01

    Although bulk Bi is a prototypical semimetal with a topologically trivial electronic band structure, we show by various quantum transport measurements that epitaxial Bi(111) thin films have unexpected and nontrivial properties. Not only the top and the bottom but also the side surfaces of epitaxial Bi(111) thin films are always robustly metallic while the interior has already become insulating. We identify the coupling between the top and the bottom surface states that drives the two originally independent surface conducting channels into a single connected one. The properties of Bi(111) thin films realized could lead to promising applications in spintronics.

  11. Impact of storm-induced cooling of sea surface temperature on large turbulent eddies and vertical turbulent transport in the atmospheric boundary layer of Hurricane Isaac

    Science.gov (United States)

    Zhu, Ping; Wang, Yuting; Chen, Shuyi S.; Curcic, Milan; Gao, Cen

    2016-01-01

    Roll vortices in the atmospheric boundary layer (ABL) are important to oil operation and oil spill transport. This study investigates the impact of storm-induced sea surface temperature (SST) cooling on the roll vortices generated by the convective and dynamic instability in the ABL of Hurricane Isaac (2012) and the roll induced transport using hindcasting large eddy simulations (LESs) configured from the multiply nested Weather Research & Forecasting model. Two experiments are performed: one forced by the Unified Wave INterface - Coupled Model and the other with the SST replaced by the NCEP FNL analysis that does not include the storm-induced SST cooling. The simulations show that the roll vortices are the prevalent eddy circulations in the ABL of Isaac. The storm-induced SST cooling causes the ABL stability falls in a range that satisfies the empirical criterion of roll generation by dynamic instability, whereas the ABL stability without considering the storm-induced SST cooling meets the criterion of roll generation by convective instability. The ABL roll is skewed and the increase of convective instability enhances the skewness. Large convective instability leads to large vertical transport of heat and moisture; whereas the dominant dynamic instability results in large turbulent kinetic energy but relatively weak heat and moisture transport. This study suggests that failure to consider roll vortices or incorrect initiation of dynamic and convective instability of rolls in simulations may substantially affect the transport of momentum, energy, and pollutants in the ABL and the dispersion/advection of oil spill fume at the ocean surface.

  12. Twelve testable hypotheses on the geobiology of weathering.

    Science.gov (United States)

    Brantley, S L; Megonigal, J P; Scatena, F N; Balogh-Brunstad, Z; Barnes, R T; Bruns, M A; Van Cappellen, P; Dontsova, K; Hartnett, H E; Hartshorn, A S; Heimsath, A; Herndon, E; Jin, L; Keller, C K; Leake, J R; McDowell, W H; Meinzer, F C; Mozdzer, T J; Petsch, S; Pett-Ridge, J; Pregitzer, K S; Raymond, P A; Riebe, C S; Shumaker, K; Sutton-Grier, A; Walter, R; Yoo, K

    2011-03-01

    Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby controlling the location and extent of biological weathering. (2) Biological stoichiometry drives changes in mineral stoichiometry and distribution through weathering. (3) On landscapes experiencing little erosion, biology drives weathering during initial succession, whereas weathering drives biology over the long term. (4) In eroding landscapes, weathering-front advance at depth is coupled to surface denudation via biotic processes. (5) Biology shapes the topography of the Critical Zone. (6) The impact of climate forcing on denudation rates in natural systems can be predicted from models incorporating biogeochemical reaction rates and geomorphological transport laws. (7) Rising global temperatures will increase carbon losses from the Critical Zone. (8) Rising atmospheric P(CO2) will increase rates and extents of mineral weathering in soils. (9) Riverine solute fluxes will respond to changes in climate primarily due to changes in water fluxes and secondarily through changes in biologically mediated weathering. (10) Land use change will impact Critical Zone processes and exports more than climate change. (11) In many severely altered settings, restoration of hydrological processes is possible in decades or less, whereas restoration of biodiversity and biogeochemical processes requires longer timescales. (12) Biogeochemical properties impart thresholds or tipping points beyond which rapid and irreversible losses of ecosystem health, function, and services can occur.

  13. Rapid transport from the surface to wells in fractured rock: a unique infiltration tracer experiment.

    Science.gov (United States)

    Levison, Jana K; Novakowski, Kent S

    2012-04-01

    A unique infiltration tracer experiment was performed whereby a fluorescent dye was applied to the land surface in an agricultural field, near Perth, Ontario, Canada, to simulate the transport of solutes to two pumped monitoring wells drilled into the granitic gneiss aquifer. This experiment, interpreted using the discrete-fracture capability of the numerical model HydroGeoSphere, showed that solute transport from the surface through thin soil (less than 2m) to wells in fractured bedrock can be extremely rapid (on the order of hours). Also, it was demonstrated that maximum concentrations of contaminants originating from the ground surface will not necessarily be the highest in the shallow aquifer horizon. These are important considerations for both private and government-owned drinking water systems that draw water from shallow fractured bedrock aquifers. This research illustrates the extreme importance of protecting drinking water at the source.

  14. Transport of particles by surface waves: a modification of the classical bouncer model

    Energy Technology Data Exchange (ETDEWEB)

    Ragulskis, M [Department of Mathematical Research in Systems, Kaunas University of Technology, Studentu 50-222, 51638 Kaunas (Lithuania); Sanjuan, M A F [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)], E-mail: minvydas.ragulskis@ktu.lt, E-mail: miguel.sanjuan@urjc.es

    2008-08-15

    We consider a ball under the influence of gravity on a platform. A propagating surface wave travels on the surface of the platform, while the platform remains motionless. This is a modification of the classical bouncing ball problem and describes the transport of particles by surface waves. Phase and velocity maps cannot be expressed in an explicit form owing to implicit formulations, and no formal analytical analysis is possible. Numerical analysis shows that the transition to chaos is produced via a period doubling route, which is a common property for classical bouncers. The bouncing process can be sensitive to the initial conditions, which can build the ground for control techniques that can dramatically increase the effectiveness of particle transport in practical applications.

  15. Intercomparison of the Performance of CLM3, NOAH, RUC, and STD Land Surface Schemes in the Weather and Research Forecasting Model

    Science.gov (United States)

    Jin, J.; Miller, N.

    2007-12-01

    The Community Land Model version 3 (CLM3) developed by the National Center for Atmospheric Research (NCAR) was coupled into the Weather Research and Forecasting (WRF) Model version 2.2. The performance of WRF-CLM3 in predicting regional climate was quantitatively compared with that of WRF coupled to the soil thermal diffusion (STD), Rapid Update Cycle, and NOAH Land Surface Schemes. These land surface schemes represent a range of complexity within land-surface schemes. CLM3 is the most sophisticated model, with detailed snow and vegetation processes. The STD scheme is oversimplified, which only calculates soil temperature and neglects vegetation and snow physics. The RUC and NOAH schemes are intermediate in the detail, and the major deference between them is that RUC has a multi-layer snow scheme, and Noah has a single snow layer lumped with the topmost soil layer. WRF was driven by the National Centers for Environmental Prediction Reanalysis data II with each of these land surface schemes for one-year simulations over the period, 1 October 1995 to 30 September 1996, resulting in four one-year simulations for intercomparison. Each simulation has 30km-10km two-way nested domains. The 30 km domain includes the western U.S. and eastern Pacific, and the inner domain includes California and parts of Nevada, Oregon, and the eastern Pacific. Our analysis shows that WRF-CLM3 outperforms WRF-RUC, WRF-NOAH, and WRF-STD in simulating temperature and snow when compared with observations. The WRF-STD scheme, which does not include snow and vegetation processes resulted in the poorest results, with a dramatic overestimation of surface air temperature. However, regardless of the land surface scheme chosen, WRF reasonably well reproduces the winter precipitation, a major water resource for California, suggesting that the linkage between land surface processes and precipitation is not explicit. In general, land surface schemes play a significant role in the simulation of regional

  16. The Effect of Surface Roughness on Fluid Configuration and Solute Transport in Unsaturated Porous Media

    Science.gov (United States)

    Kibbey, T. C.

    2013-12-01

    When describing the configuration of water in unsaturated media, a distinction is often made between water that is held by capillary forces between grains (capillary water), and water associated with adsorbed films on solid surfaces (film water). The objective of this work was to better understand the nature of the water associated with solid surfaces, with emphasis on understanding the configuration of water on rough natural surfaces. Stereoscopic SEM was used to determine elevation maps on a range of different natural solid surfaces. A computational technique was then developed to calculate the configuration of water on the surfaces as a function of capillary pressure. Calculations of fluid configurations show that, except at extremely high capillary pressures, fluid configuration is dominated by bridging of surface roughness features, even for extremely smooth surfaces. Results suggest that true adsorbed films are likely extremely rare in the environment except under near-dry, ultra-high capillary pressure conditions. This result has significant implications for understanding fate and transport within the unsaturated zone. Preliminary simulations exploring the impact on transport will be discussed.

  17. Fort Campbell, Campbell AAF, Kentucky. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    Science.gov (United States)

    1982-12-01

    R SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) ,4671 FT CAMPRELL KY 73-81 "A-’ ALL WEATHtR. SPEED MAN...34., AFETAC SURFACE WINDS A2 EATHR SEV1CL/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 74f-71 FT CAMPRELL KY 73-81...SERVI11/mAC ’ 467 . FT CAMPRELL KY 73-31 Ju’. e PERCENTAGE FREQUENCY OF OCCURRENCE (FROM HOURLY OBSERVATIONS) VfSf bitT STAT JTE -ILES !Ci Nu, i I -o i > I

  18. Surface Effect on Oil Transportation in Nanochannel: a Molecular Dynamics Study.

    Science.gov (United States)

    Zheng, Haixia; Du, Yonggang; Xue, Qingzhong; Zhu, Lei; Li, Xiaofang; Lu, Shuangfang; Jin, Yakang

    2017-12-01

    In this work, we investigate the dynamics mechanism of oil transportation in nanochannel using molecular dynamics simulations. It is demonstrated that the interaction between oil molecules and nanochannel has a great effect on the transportation properties of oil in nanochannel. Because of different interactions between oil molecules and channel, the center of mass (COM) displacement of oil in a 6-nm channel is over 30 times larger than that in a 2-nm channel, and the diffusion coefficient of oil molecules at the center of a 6-nm channel is almost two times more than that near the channel surface. Besides, it is found that polarity of oil molecules has the effect on impeding oil transportation, because the electrostatic interaction between polar oil molecules and channel is far larger than that between nonpolar oil molecules and channel. In addition, channel component is found to play an important role in oil transportation in nanochannel, for example, the COM displacement of oil in gold channel is very few due to great interaction between oil and gold substrate. It is also found that nano-sized roughness of channel surface greatly influences the speed and flow pattern of oil. Our findings would contribute to revealing the mechanism of oil transportation in nanochannels and therefore are very important for design of oil extraction in nanochannels.

  19. Influence of enterococcal surface protein (esp) on the transport of Enterococcus faecium within saturated quartz sands.

    Science.gov (United States)

    Johanson, Jennifer J; Feriancikova, Lucia; Xu, Shangping

    2012-02-07

    Enterococcus was selected by US EPA as a Gram-positive indicator microorganism for groundwater fecal contamination. It was recently reported that enterococcal surface protein (esp) was more prevalent in Enterococcus from human sources than in Enterococcus from nonhuman sources and esp could potentially be used as a source tracking tool for fecal contamination (Scott et al., 2005). In this research, we performed laboratory column transport experiments to investigate the transport of Enterococcus faecium within saturated quartz sands. Particularly, we used a wild type strain (E1162) and a mutant (E1162Δesp) to examine the influence of esp on the transport behavior of E. faecium. Our results showed that esp could significantly enhance the attachment of E. faecium cells onto the surface of silica sands and thus lower the mobility of E. faecium within sand packs. Cell surface properties (e.g., zeta potential) were determined and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was applied to explain the effects of esp on the retention of E. faecium. Overall, our results suggested that E. faecium strains with esp could display lower mobility within saturated sand packs than E. faecium strains without esp. The disparity in the transport behavior of E. faecium with and without esp could limit the effectiveness of esp as a source tracking tool within the groundwater system.

  20. Electronic transport at semiconductor surfaces - from point-contact transistor to micro-four-point probes

    DEFF Research Database (Denmark)

    Hasegawa, S.; Grey, Francois

    2002-01-01

    show that this type of conduction is measurable using new types of experimental probes, such as the multi-tip scanning tunnelling microscope and the micro-four-point probe. The resulting electronic transport properties are intriguing, and suggest that semiconductor surfaces should be considered......The electrical properties of semiconductor surfaces have played a decisive role in one of the most important discoveries of the last century, transistors. In the 1940s, the concept of surface states-new electron energy levels characteristic of the surface atoms-was instrumental in the fabrication...... of the first point-contact transistors, and led to the successful fabrication of field-effect transistors. However, to this day, one property of semiconductor surface states remains poorly understood, both theoretically and experimentally. That is the conduction of electrons or holes directly through...

  1. Magnetically Controlled Electronic Transport Properties of a Ferromagnetic Junction on the Surface of a Topological Insulator

    Science.gov (United States)

    Liu, Zheng-Qin; Wang, Rui-Qiang; Deng, Ming-Xun; Hu, Liang-Bin

    2015-06-01

    We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topological insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted: observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electrically controlled magnetization switching. Supported by National Natural Science Foundation of China under Grant Nos. 11174088, 11175067, 11274124

  2. Measurements of wind friction speeds over lava surfaces and assessment of sediment transport

    Science.gov (United States)

    Greeley, Ronald; Iversen, James D.

    1987-01-01

    Wind velocity profiles were obtained over alluvial plains, lava flows, and a cinder cone in the Mojave Desert to determine the wind shear and the potential for particle transport. It was found that aerodynamic roughness for winds increases nearly a factor of 5 as flow crosses from the alluvium to the lava surface, resulting in wind shear that is 21 percent greater. Thus, wind erosion and sand flux may be substantially enhanced over the lava field. Moreover, wind flow turbulence is enhanced in the wake of the cinder cone, which also increases erosion and sediment transportation by the wind.

  3. A controlled field pilot for testing near surface CO2 detection techniques and transport models

    Science.gov (United States)

    Spangler, L.H.; Dobeck, L.M.; Repasky, K.; Nehrir, A.; Humphries, S.; Keith, C.; Shaw, J.; Rouse, J.; Cunningham, A.; Benson, S.; Oldenburg, C.M.; Lewicki, J.L.; Wells, A.; Diehl, R.; Strazisar, B.; Fessenden, J.; Rahn, Thomas; Amonette, J.; Barr, J.; Pickles, W.; Jacobson, J.; Silver, E.; Male, E.; Rauch, H.; Gullickson, K.; Trautz, R.; Kharaka, Y.; Birkholzer, J.; Wielopolski, L.

    2009-01-01

    A field facility has been developed to allow controlled studies of near surface CO2 transport and detection technologies. The key component of the facility is a shallow, slotted horizontal well divided into six zones. The scale and fluxes were designed to address large scale CO2 storage projects and desired retention rates for those projects. A wide variety of detection techniques were deployed by collaborators from 6 national labs, 2 universities, EPRI, and the USGS. Additionally, modeling of CO2 transport and concentrations in the saturated soil and in the vadose zone was conducted. An overview of these results will be presented. ?? 2009 Elsevier Ltd. All rights reserved.

  4. The Kuroshio Transport East of Taiwan and the Sea Surface Height Anomaly from the Interior Ocean

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; LIU Qinyu; JIA Yinglai

    2004-01-01

    The relationship between the Kuroshio transport to the east of Taiwan and the SSHA(Sea Surface Height Anomaly)field is studied based on the World Ocean Circulation Experiment(WOCE)PCM-1 moored current meter array observation, the satellite altimeter data from the MSLA(Map of Sea Level Anomaly)products merged with the ERS and TOPEX/POSEIDON(T/P)data sets, and the WOCE satellite-tracked drifting buoy data. It is confirmed that the Kuroshio transport across PCM-1 array highly correlates with the SSHA upstream(22°-24°, 121.75°-124°E). The SSHA is not locally generated by the developed Kuroshio meandering but is from the interior ocean and is propagating westward or northwestward. During the period from October 1992 to January 1998, two events of the northwestward propagating negative SSHA occurred, during which the SSHA merged into the Kuroshio and caused the remarkable low transport events in contrast to the normal westward propagating negative SSHA. It is also shown that the lower Kuroshio transport event would be generated in different ways. The negative anomaly in the upstream of PCM-1 array can reduce the Kuroshio transport by either offshore or onshore Kuroshio meandering. The positive anomaly, which is strong enough to detour the Kuroshio, can cause an offshore meandering and a low transport event at the PCM-1 array.

  5. Martin Marietta Airfield, Baltimore, Maryland. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    Science.gov (United States)

    1979-08-02

    PARTSI PRECIPITATION PSYCHROMITRIC-DRY VS WET IULS SNOWFALL M9EAN & SYD DIV SNOW DEPTH (DRY RLL, WIT SULD, & DEW POINT) PARKC SURFACE WINDSREAIEUM iT... WiT -;2.2 1 s94o76 97.o 9 7 ’n --47 . 9 8- -9.4 F9. 7 _ 45.8 7-,P 77,4 Ld1.( It, d.2 Tj,3 -u22 193 ,1L9 4 ,6 9 7 ,. 97,0 27,9 9Ao8 99.4(p0o TOTAL...Q b17 85,5 67,7 4o 89 89,4 89,9 89o8 69 R 9,8 89. 89,8 89,b-a 8 0 , l a " I .3 3 , 3 7 2 8 9 . 9 , 1. 9 1 . a 9 : 3 9 2 , . 9 2 , a . s 4 9 2 93

  6. Predicting uncertainty in sediment transport and landscape evolution - the influence of initial surface conditions

    Science.gov (United States)

    Hancock, G. R.; Coulthard, T. J.; Lowry, J. B. C.

    2016-05-01

    Numerical landscape evolution models were initially developed to examine natural catchment hydrology and geomorphology and have become a common tool to examine geomorphic behaviour over a range of time and space scales. These models all use a digital elevation model (DEM) as a representation of the landscape surface and a significant issue is the quality and resolution of this surface. Here we focus on how subtle perturbations or roughness on the DEM surface can produce alternative model results. This study is carried out by randomly varying the elevations of the DEM surface and examining the effect on sediment transport rates and geomorphology for a proposed rehabilitation design for a post-mining landscape using multiple landscape realisations with increasing magnitudes of random changes. We show that an increasing magnitude of random surface variability does not appear to have any significant effect on sediment transport over millennial time scales. However, the random surface variability greatly changes the temporal pattern or delivery of sediment output. A significant finding is that all simulations at the end of the 10,000 year modelled period are geomorphologically similar and present a geomorphological equifinality. However, the individual patterns of erosion and deposition were different for repeat simulations with a different sequence of random perturbations. The alternative positions of random perturbations strongly influence local patterns of hillslope erosion and evolution together with the pattern and behaviour of deposition. The findings demonstrate the complex feedbacks that occur even within a simple modelled system.

  7. Enhanced Hydrogen Transport over Palladium Ultrathin Films through Surface Nanostructure Engineering.

    Science.gov (United States)

    Abate, Salvatore; Giorgianni, Gianfranco; Gentiluomo, Serena; Centi, Gabriele; Perathoner, Siglinda

    2015-11-01

    Palladium ultrathin films (around 2 μm) with different surface nanostructures are characterized by TEM, SEM, AFM, and temperature programmed reduction (TPR), and evaluated in terms of H2 permeability and H2-N2 separation. A change in the characteristics of Pd seeds by controlled oxidation-reduction treatments produces films with the same thickness, but different surface and bulk nanostructure. In particular, the films have finer and more homogeneous Pd grains, which results in lower surface roughness. Although all samples show high permeo-selectivity to H2 , the samples with finer grains exhibit enhanced permeance and lower activation energy for H2 transport. The analysis of the data suggests that grain boundaries between the Pd grains at the surface favor H2 transfer from surface to subsurface. Thus, the surface nanostructure plays a relevant role in enhancing the transport of H2 over the Pd ultrathin film, which is an important aspect to develop improved membranes that function at low temperatures and toward new integrated process architectures in H2 and syngas production with enhanced sustainability.

  8. Relationship between Surface Urban Heat Island intensity and sensible heat flux retrieved from meteorological parameters observed by road weather stations in urban area

    Science.gov (United States)

    Gawuć, Lech

    2017-04-01

    Urban Heat Island (UHI) is a direct consequence of altered energy balance in urban areas (Oke 1982). There has been a significant effort put into an understanding of air temperature variability in urban areas and underlying mechanisms (Arnfield 2003, Grimmond 2006, Stewart 2011, Barlow 2014). However, studies that are concerned on surface temperature are less frequent. Therefore, Voogt & Oke (2003) proposed term "Surface Urban Heat Island (SUHI)", which is analogical to UHI and it is defined as a difference in land surface temperature (LST) between urban and rural areas. SUHI is a phenomenon that is not only concerned with high spatial variability, but also with high temporal variability (Weng and Fu 2014). In spite of the fact that satellite remote sensing techniques give a full spatial pattern over a vast area, such measurements are strictly limited to cloudless conditions during a satellite overpass (Sobrino et al., 2012). This significantly reduces the availability and applicability of satellite LST observations, especially over areas and seasons with high cloudiness occurrence. Also, the surface temperature is influenced by synoptic conditions (e.g., wind and humidity) (Gawuc & Struzewska 2016). Hence, utilising single observations is not sufficient to obtain a full image of spatiotemporal variability of urban LST and SUHI intensity (Gawuc & Struzewska 2016). One of the possible solutions would be a utilisation of time-series of LST data, which could be useful to monitor the UHI growth of individual cities and thus, to reveal the impact of urbanisation on local climate (Tran et al., 2006). The relationship between UHI and synoptic conditions have been summarised by Arnfield (2003). However, similar analyses conducted for urban LST and SUHI are lacking. We will present analyses of the relationship between time series of remotely-sensed LST and SUHI intensity and in-situ meteorological observations collected by road weather stations network, namely: road surface

  9. Thermally driven transverse transports and magnetic dynamics on a topological surface capped with a ferromagnet strip

    Science.gov (United States)

    Deng, Ming-Xun; Zhong, Ming; Zheng, Shi-Han; Qiu, Jian-Ming; Yang, Mou; Wang, Rui-Qiang

    2016-02-01

    We theoretically study thermally driven transport of the Dirac fermions on the surface of a topological insulator capped with a ferromagnet strip. The generation and manipulation of anomalous Hall and Nernst effects are analyzed, in which the in-plane magnetization of the ferromagnet film is found to take a decisive role. This scenario is distinct from that modulated by Berry phase where the in-plane magnetization is independent. We further discuss the thermal spin-transfer torque as a backaction of the thermoelectric transports on the magnetization and calculate the dynamics of the anomalous Hall and Nernst effects self-consistently. It is found that the magnitude of the long-time steady Hall and Nernst conductance is determined by competition between the magnetic anisotropy and current-induced effective anisotropy. These results open up a possibility of magnetically controlling the transverse thermoelectric transports or thermally manipulating the magnet switching.

  10. Reliable transport through a microfabricated X-junction surface-electrode ion trap

    CERN Document Server

    Wright, Kenneth; Faircloth, Daniel L; Volin, Curtis; Doret, S Charles; Hayden, Harley; Pai, C-S; Landgren, David W; Denison, Douglas; Killian, Tyler; Slusher, Richart E; Harter, Alexa W

    2012-01-01

    We report the design, fabrication, and characterization of a microfabricated surface-electrode ion trap that supports controlled transport through the two-dimensional intersection of linear trapping zones arranged in a ninety-degree cross. The trap is fabricated with very-large-scalable-integration (VLSI) techniques which are compatible with scaling to a larger quantum information processor. The shape of the radio-frequency (RF) electrodes is optimized with a genetic algorithm to minimize axial pseudopotential barriers and to minimize ion heating during transport. Seventy-eight independent DC control electrodes enable fine control of the trapping potentials. We demonstrate reliable ion transport between junction legs, trapping of ion chains with nearly-equal spacing in one of the trap's linear sections, and merging and splitting ions from these chains. Doppler-cooled ions survive more than 10^5 round-trip transits between junction legs without loss and more than sixty-five consecutive round trips without lase...

  11. Photoluminescence Imaging of Polyfluorene Surface Structures on Semiconducting Carbon Nanotubes: Implications for Thin Film Exciton Transport.

    Science.gov (United States)

    Hartmann, Nicolai F; Pramanik, Rajib; Dowgiallo, Anne-Marie; Ihly, Rachelle; Blackburn, Jeffrey L; Doorn, Stephen K

    2016-12-27

    Single-walled carbon nanotubes (SWCNTs) have potential to act as light-harvesting elements in thin film photovoltaic devices, but performance is in part limited by the efficiency of exciton diffusion processes within the films. Factors contributing to exciton transport can include film morphology encompassing nanotube orientation, connectivity, and interaction geometry. Such factors are often defined by nanotube surface structures that are not yet well understood. Here, we present the results of a combined pump-probe and photoluminescence imaging study of polyfluorene (PFO)-wrapped (6,5) and (7,5) SWCNTs that provide additional insight into the role played by polymer structures in defining exciton transport. Pump-probe measurements suggest exciton transport occurs over larger length scales in films composed of PFO-wrapped (7,5) SWCNTs, compared to those prepared from PFO-bpy-wrapped (6,5) SWCNTs. To explore the role the difference in polymer structure may play as a possible origin of differing transport behaviors, we performed a photoluminescence imaging study of individual polymer-wrapped (6,5) and (7,5) SWCNTs. The PFO-bpy-wrapped (6,5) SWCNTs showed more uniform intensity distributions along their lengths, in contrast to the PFO-wrapped (7,5) SWCNTs, which showed irregular, discontinuous intensity distributions. These differences likely originate from differences in surface coverage and suggest the PFO wrapping on (7,5) nanotubes produces a more open surface structure than is available with the PFO-bpy wrapping of (6,5) nanotubes. The open structure likely leads to improved intertube coupling that enhances exciton transport within the (7,5) films, consistent with the results of our pump-probe measurements.

  12. Photoluminescence Imaging of Polyfluorene Surface Structures on Semiconducting Carbon Nanotubes: Implications for Thin Film Exciton Transport

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Nicolai F.; Pramanik, Rajib; Dowgiallo, Anne-Marie; Ihly, Rachelle; Blackburn, Jeffrey L.; Doorn, Stephen K.

    2016-12-27

    Single-walled carbon nanotubes (SWCNTs) have potential to act as light-harvesting elements in thin film photovoltaic devices, but performance is in part limited by the efficiency of exciton diffusion processes within the films. Factors contributing to exciton transport can include film morphology encompassing nanotube orientation, connectivity, and interaction geometry. Such factors are often defined by nanotube surface structures that are not yet well understood. Here, we present the results of a combined pump-probe and photoluminescence imaging study of polyfluorene (PFO)-wrapped (6,5) and (7,5) SWCNTs that provide additional insight into the role played by polymer structures in defining exciton transport. Pump-probe measurements suggest exciton transport occurs over larger length scales in films composed of PFO-wrapped (7,5) SWCNTs, compared to those prepared from PFO-bpy-wrapped (6,5) SWCNTs. To explore the role the difference in polymer structure may play as a possible origin of differing transport behaviors, we performed a photoluminescence imaging study of individual polymer-wrapped (6,5) and (7,5) SWCNTs. The PFO-bpy-wrapped (6,5) SWCNTs showed more uniform intensity distributions along their lengths, in contrast to the PFO-wrapped (7,5) SWCNTs, which showed irregular, discontinuous intensity distributions. These differences likely originate from differences in surface coverage and suggest the PFO wrapping on (7,5) nanotubes produces a more open surface structure than is available with the PFO-bpy wrapping of (6,5) nanotubes. The open structure likely leads to improved intertube coupling that enhances exciton transport within the (7,5) films, consistent with the results of our pump-probe measurements.

  13. Tuning thermal transport in ultrathin silicon membranes by surface nanoscale engineering.

    Science.gov (United States)

    Neogi, Sanghamitra; Reparaz, J Sebastian; Pereira, Luiz Felipe C; Graczykowski, Bartlomiej; Wagner, Markus R; Sledzinska, Marianna; Shchepetov, Andrey; Prunnila, Mika; Ahopelto, Jouni; Sotomayor-Torres, Clivia M; Donadio, Davide

    2015-04-28

    A detailed understanding of the connections of fabrication and processing to structural and thermal properties of low-dimensional nanostructures is essential to design materials and devices for phononics, nanoscale thermal management, and thermoelectric applications. Silicon provides an ideal platform to study the relations between structure and heat transport since its thermal conductivity can be tuned over 2 orders of magnitude by nanostructuring. Combining realistic atomistic modeling and experiments, we unravel the origin of the thermal conductivity reduction in ultrathin suspended silicon membranes, down to a thickness of 4 nm. Heat transport is mostly controlled by surface scattering: rough layers of native oxide at surfaces limit the mean free path of thermal phonons below 100 nm. Removing the oxide layers by chemical processing allows us to tune the thermal conductivity over 1 order of magnitude. Our results guide materials design for future phononic applications, setting the length scale at which nanostructuring affects thermal phonons most effectively.

  14. New efficient optimal mass transport approach for single freeform surface design

    CERN Document Server

    Bösel, Christoph

    2015-01-01

    We present a new optimal mass transport approach for the design of a continuous single freeform surface for collimated beams. By applying the law of reflection/refraction and the well-known integrability condition, it is shown that the design process in a small angle approximation can be decoupled into the calculation of a raymapping by optimal mass transport methods and the subsequent construction of the freeform surface by a steady linear advection equation. It is shown that the solution of this linear advection equation can be obtained by a decomposition into two dimensional subproblems and solving these by standard integrals. The efficiency of the method is demonstrated by applying it to two challenging design examples.

  15. Taking advantage of reduced droplet-surface interaction to optimize transport of bioanalytes in digital microfluidics.

    Science.gov (United States)

    Freire, Sergio L S; Thorne, Nathaniel; Wutkowski, Michael; Dao, Selina

    2014-11-10

    Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of "lab-on-a-chip" platforms. Often, droplet motion relies on the wetting of a surface, directly associated with the application of an electric field; surface interactions, however, make motion dependent on droplet contents, limiting the breadth of applications of the technique. Some alternatives have been presented to minimize this dependence. However, they rely on the addition of extra chemical species to the droplet or its surroundings, which could potentially interact with droplet moieties. Addressing this challenge, our group recently developed Field-DW devices to allow the transport of cells and proteins in DMF, without extra additives. Here, the protocol for device fabrication and operation is provided, including the electronic interface for motion control. We also continue the studies with the devices, showing that multicellular, relatively large, model organisms can also be transported, arguably unaffected by the electric fields required for device operation.

  16. Anisotropic surface hole-transport property of triphenylamine-derivative single crystal prepared by solution method

    Science.gov (United States)

    Umeda, Minoru; Katagiri, Mitsuhiko; Shironita, Sayoko; Nagayama, Norio

    2016-12-01

    This paper reports the anisotropic hole transport at the triphenylamine-derivative single crystal surface prepared by a solution method. Triphenylamine derivatives are commonly used in a hole-transport material for organic photoconductors of laser-beam printers, in which the materials are used as an amorphous form. For developing organic photovoltaics using the photoconductor's technology, preparation of a single crystal seems to be a specific way by realizing the high mobility of an organic semiconductor. In this study, a single crystal of 4-(2,2-diphenylethenyl)-N,N-bis(4-methylphenyl)-benzenamine (TPA) was prepared and its anisotropic hole-transport property measured. First, the hole-transport property of the TPA was investigated based on its chemical structure and electrochemical redox characteristics. Next, a large-scale single crystal formation at a high rate was developed by employing a solution method based on its solubility and supersolubility curves. The grown TPA was found to be a single crystal based on the polarization micrograph observation and crystallographic analysis. For the TPA single crystal, an anisotropic surface conduction was found, which was well explained by its molecular stack structure. The measured current in the long-axis direction is one order of magnitude greater than that of amorphous TPA.

  17. Surface plasmon enhanced quantum transport in a hybrid metal nanoparticle array

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Lin; Nan, Yali; Xu, Shang; Zhang, Sishi; Han, Min, E-mail: sjhanmin@nju.edu.cn

    2014-07-18

    Hybrid Pd–Ag nanoparticle arrays composed of randomly distributed Pd nanoparticles in dense packing and a small number of dispersed Ag nanoparticles were fabricated with controlled coverage. Photo-enhanced conductance was observed in the nanoparticle arrays. Largest enhancement, which can be higher than 20 folds, was obtained with 450 nm light illumination. This wavelength was found to correlate with the surface plasmon resonance of the Ag nanoparticles. Electron transport measurements showed there were significant Coulomb blockade in the nanoparticle arrays and the blockade could be overcome with the surface plasmon enhanced local field of Ag nanoparticles induced by light illumination. - Highlights: • We study photo-enhanced electron conductance of a hybrid Pd–Ag nanoparticle array. • The light-induced conductance enhancement is as high as 20 folds at 10 K. • The enhancement is correlate with the surface plasmon resonance of Ag nanoparticles. • Coulomb blockades is overcome with the surface plasmon enhanced local field.

  18. Modeling comprehensive chemical composition of weathered oil following a marine spill to predict ozone and potential secondary aerosol formation and constrain transport pathways

    Science.gov (United States)

    Drozd, Greg T.; Worton, David R.; Aeppli, Christoph; Reddy, Christopher M.; Zhang, Haofei; Variano, Evan; Goldstein, Allen H.

    2015-11-01

    Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate-volatile and semivolatile compounds (IVOC, SVOC), which cause secondary organic aerosol (SOA) and ozone production. The Deepwater Horizon (DWH) disaster in the northern Gulf of Mexico during Spring/Summer of 2010 presented a unique opportunity to observe SOA production due to an oil spill. To better understand these observations, we conducted measurements and modeled oil evaporation utilizing unprecedented comprehensive composition measurements, achieved by gas chromatography with vacuum ultraviolet time of flight mass spectrometry (GC-VUV-HR-ToFMS). All hydrocarbons with 10-30 carbons were classified by degree of branching, number of cyclic rings, aromaticity, and molecular weight; these hydrocarbons comprise ˜70% of total oil mass. Such detailed and comprehensive characterization of DWH oil allowed bottom-up estimates of oil evaporation kinetics. We developed an evaporative model, using solely our composition measurements and thermodynamic data, that is in excellent agreement with published mass evaporation rates and our wind-tunnel measurements. Using this model, we determine surface slick samples are composed of oil with a distribution of evaporative ages and identify and characterize probable subsurface transport of oil.

  19. Density wave like transport anomalies in surface doped Na2IrO3

    Directory of Open Access Journals (Sweden)

    Kavita Mehlawat

    2017-05-01

    Full Text Available We report that the surface conductivity of Na2IrO3 crystal is extremely tunable by high energy Ar plasma etching and can be tuned from insulating to metallic with increasing etching time. Temperature dependent electrical transport for the metallic samples show signatures of first order phase transitions which are consistent with charge or spin density wave like phase transitions predicted recently. Additionally, grazing-incidence small-angle x-ray scattering (GISAXS reveal that the room temperature surface structure of Na2IrO3 does not change after plasma etching.

  20. Surface and transport properties of Cu-Sn-Ti liquid alloys

    Institute of Scientific and Technical Information of China (English)

    R. Novakovic; E. Ricci; S. Amore; T. Lanata

    2006-01-01

    The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and Sn-Ti subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattce theory (QLT). This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.

  1. 49 CFR 176.160 - Protection against weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Protection against weather. 176.160 Section 176.160 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Protection against weather. Any person loading or unloading packages containing Class 1 (explosive)...

  2. Stochastic model for photoinduced surface relief grating formation through molecular transport in polymer films.

    Energy Technology Data Exchange (ETDEWEB)

    Juan, M.; Plain, J.; Bachelot, R.; Royer, P.; Gray, S. K.; Wiederrecht, G. P.; Univ. de Technologie de Troyes

    2008-09-01

    We use a stochastic model to study photoinduced surface relief grating (SRG) formation due to molecular transport in azobenzene polymer films. The model is shown to reproduce the essential experimental features of SRG formation. In particular, it predicts SRG formation under both p and s polarizations, and the double peaked topographies that can occur at early times of the process. The evolving molecular positions and orientations during exposure are also followed, providing a useful mechanistic picture of SRG dynamics.

  3. Transportation-Driven Mars Surface Operations Supporting an Evolvable Mars Campaign

    Science.gov (United States)

    Toups, Larry; Brown, Kendall; Hoffman, Stephen J.

    2015-01-01

    This paper describes the results of a study evaluating options for supporting a series of human missions to a single Mars surface destination. In this scenario the infrastructure emplaced during previous visits to this site is leveraged in following missions. The goal of this single site approach to Mars surface infrastructure is to enable "Steady State" operations by at least 4 crew for up to 500 sols at this site. These characteristics, along with the transportation system used to deliver crew and equipment to and from Mars, are collectively known as the Evolvable Mars Campaign (EMC). Information in this paper is presented in the sequence in which it was accomplished. First, a logical buildup sequence of surface infrastructure was developed to achieve the desired "Steady State" operations on the Mars surface. This was based on a concept of operations that met objectives of the EMC. Second, infrastructure capabilities were identified to carry out this concept of operations. Third, systems (in the form of conceptual elements) were identified to provide these capabilities. This included top-level mass, power and volume estimates for these elements. Fourth, the results were then used in analyses to evaluate three options (18t, 27t, and 40t landed mass) of Mars Lander delivery capability to the surface. Finally, Mars arrival mass estimates were generated based upon the entry, descent, and landing requirements for inclusion in separate assessments of in-space transportation capabilities for the EMC.

  4. Precipitable water and surface humidity over global oceans from special sensor microwave imager and European Center for Medium Range Weather Forecasts

    Science.gov (United States)

    Liu, W. T.; Tang, Wenqing; Wentz, Frank J.

    1992-01-01

    Global fields of precipitable water W from the special sensor microwave imager were compared with those from the European Center for Medium Range Weather Forecasts (ECMWF) model. They agree over most ocean areas; both data sets capture the two annual cycles examined and the interannual anomalies during an ENSO episode. They show significant differences in the dry air masses over the eastern tropical-subtropical oceans, particularly in the Southern Hemisphere. In these regions, comparisons with radiosonde data indicate that overestimation by the ECMWF model accounts for a large part of the differences. As a check on the W differences, surface-level specific humidity Q derived from W, using a statistical relation, was compared with Q from the ECMWF model. The differences in Q were found to be consistent with the differences in W, indirectly validating the Q-W relation. In both W and Q, SSMI was able to discern clearly the equatorial extension of the tongues of dry air in the eastern tropical ocean, while both ECMWF and climatological fields have reduced spatial gradients and weaker intensity.

  5. River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone: U TRANSPORT IN A GROUNDWATER-SURFACE WATER TRANSITION ZONE

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M. [Pacific Northwest National Laboratory, Richland Washington USA; Chen, Xingyuan [Pacific Northwest National Laboratory, Richland Washington USA; Murray, Chris [Pacific Northwest National Laboratory, Richland Washington USA; Hammond, Glenn [Sandia National Laboratories, Albuquerque New Mexico USA

    2016-03-01

    A tightly spaced well-field within a groundwater uranium (U) plume in the groundwater-surface water transition zone was monitored for a three year period for groundwater elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from mountain snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (Uaq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time series trends for Uaq and SpC were complex and displayed large temporal well-to well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common temporal behaviors resulting from the intrusion dynamics of river water and the location of source terms. Concentration hot spots were observed in groundwater that varied in location with increasing water table elevation. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While uranium time-series concentration trends varied significantly from year to year as a result of climate-caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of the river water intrusion event.

  6. Impact of lux gene insertion on bacterial surface properties and transport.

    Science.gov (United States)

    Chen, Gang; Srinivasa Ranga, Vijay Penagonda; Mao, Yongjun; Chen, Kevin; Qiao, Hanzi

    2008-03-01

    Genetic markers have been in popular use for tracing microbial movement in the environment. However, the impact of genetic marker insertion on microbial surface properties and consequent transport is often ignored. For this research, we investigated the impact of luminescence-based genetic marker insertion on bacterial surface properties and transport. Typical Gram-positive bacterial strains of Lactobacillus casei, Streptococcus mitis and Micrococcus luteus were used as model bacterial strains in this research. We manipulated gene transfer to observe the impact of lux gene insertion on bacterial surface properties based on contact angle measurements, and we conducted column experiments to evaluate the impact of lux gene insertion on bacterial transport. After lux gene insertion, bacterial interactions with the porous media increased, demonstrating stronger deposition potential in the porous media. Accordingly, retention of the daughter strains increased. Lux gene insertion also resulted in an increase in bacterial dispersion and equilibrium adsorption in the porous media. The bacterial deposition coefficient was found to correlate with the free energy of interactions between bacteria and the porous media.

  7. Passive scalar transport to and from the surface of a Pocillopora coral colony

    Science.gov (United States)

    Hossain, Md Monir; Staples, Anne

    2016-11-01

    Three-dimensional simulations of flow through a single Pocillopora coral colony were performed to examine the interaction between the flow conditions and scalar transport near a coral colony. With corals currently undergoing a third global bleaching event, a fuller understanding of the transport of nutrients, weak temperature gradients, and other passive scalars to and from the coral polyp tissue is more important than ever. The complex geometry of a coral colony poses a significant challenge for numerical simulation. To simplify grid generation and minimize computational cost, the immersed boundary method was implemented. Large eddy simulation was chosen as the framework to capture the turbulent flow field in the range of realistic Reynolds numbers of 5,000 to 30,000 and turbulent Schmidt numbers of up to 1,000. Both uniform and oscillatory flows through the colony were investigated. Significant differences were found between the cases when the scalar originated at the edge of the flow domain and was transported into the colony, versus when the scalar originated on the surface of the colony and was transported away from the coral. The domain-to-colony transport rates were found to be orders of magnitude higher than the colony-to-domain rates.

  8. Impact of Tactical and Strategic Weather Avoidance on Separation Assurance

    Science.gov (United States)

    Refai, Mohamad S.; Windhorst, Robert

    2011-01-01

    The ability to keep flights away from weather hazards while maintaining aircraft-to-aircraft separation is critically important. The Advanced Airspace Concept is an automation concept that implements a ground-based strategic conflict resolution algorithm for management of aircraft separation. The impact of dynamic and uncertain weather avoidance on this concept is investigated. A strategic weather rerouting system is integrated with the Advanced Airspace Concept, which also provides a tactical weather avoidance algorithm, in a fast time simulation of the Air Transportation System. Strategic weather rerouting is used to plan routes around weather in the 20 minute to two-hour time horizon. To address forecast uncertainty, flight routes are revised at 15 minute intervals. Tactical weather avoidance is used for short term trajectory adjustments (30 minute planning horizon) that are updated every minute to address any weather conflicts (instances where aircraft are predicted to pass through weather cells) that are left unresolved by strategic weather rerouting. The fast time simulation is used to assess the impact of tactical weather avoidance on the performance of automated conflict resolution as well as the impact of strategic weather rerouting on both conflict resolution and tactical weather avoidance. The results demonstrate that both tactical weather avoidance and strategic weather rerouting increase the algorithm complexity required to find aircraft conflict resolutions. Results also demonstrate that tactical weather avoidance is prone to higher airborne delay than strategic weather rerouting. Adding strategic weather rerouting to tactical weather avoidance reduces total airborne delays for the reported scenario by 18% and reduces the number of remaining weather violations by 13%. Finally, two features are identified that have proven important for strategic weather rerouting to realize these benefits; namely, the ability to revise reroutes and the use of maneuvers

  9. Monthly Weather Review

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Supplements to the Monthly Weather Review publication. The Weather Bureau published the Monthly weather review Supplement irregularly from 1914 to 1949. The...

  10. Weather Prediction Models

    Science.gov (United States)

    Bacmeister, Julio T.

    Awareness of weather and concern about weather in the proximate future certainly must have accompanied the emergence of human self-consciousness. Although weather is a basic idea in human existence, it is difficult to define precisely.

  11. A field study of colloid transport in surface and subsurface flows

    Science.gov (United States)

    Zhang, Wei; Tang, Xiang-Yu; Xian, Qing-Song; Weisbrod, Noam; Yang, Jae E.; Wang, Hong-Lan

    2016-11-01

    Colloids have been recognized to enhance the migration of strongly-sorbing contaminants. However, few field investigations have examined combined colloid transport via surface runoff and subsurface flows. In a headwater catchment of the upper Yangtze River, a 6 m (L) by 4 m (W) sloping (6°) farmland plot was built by cement walls to form no-flow side boundaries. The plot was monitored in the summer of 2014 for the release and transport of natural colloids via surface runoff and subsurface flows (i.e., the interflow from the soil-mudrock interface and fracture flow from the mudrock-sandstone interface) in response to rain events. The water sources of the subsurface flows were apportioned to individual rain events using a two end-member model (i.e., mobile pre-event soil water extracted by a suction-cup sampler vs. rainwater (event water)) based on δ18O measurements. For rain events with high preceding soil moisture, mobile pre-event soil water was the main contributor (generally >60%) to the fracture flow. The colloid concentration in the surface runoff was 1-2 orders of magnitude higher than that in the subsurface flows. The lowest colloid concentration was found in the subsurface interflow, which was probably the result of pore-scale colloid straining mechanisms. The rainfall intensity and its temporal variation govern the dynamics of the colloid concentrations in both surface runoff and subsurface flows. The duration of the antecedent dry period affected not only the relative contributions of the rainwater and the mobile pre-event soil water to the subsurface flows but also the peak colloid concentration, particularly in the fracture flow. The rain period because their transport in association with colloids may occur rapidly over long distances via both surface runoff and subsurface flows with rainfall.

  12. Titan: Callisto With Weather?

    Science.gov (United States)

    Moore, J. M.; Pappalardo, R. T.

    2008-12-01

    Instead of being endogenically active, Titan's interior may be cold and dead. Those landforms on Titan that are unambiguously identifiable can all be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). At the scale of available imaging data, the surface is dominated by vast dune ergs and by fluvial erosion, transportation, and deposition. The sparse distribution of recognizable impact craters (themselves exogenic) is consistent with the presence of aeolian and fluvial activity sufficient to cover and or erode smaller craters, leaving only large ones. Previous suggestions of endogenically produced landforms have been, without exception, inconclusively identified. Features suggested to be cryovolcanic flows may be debris flows and other mass movements, facilitated by hydrocarbon-fluidized unconsolidated materials. Ganesa Macula has been suggested as a putative cryovolcanic dome, but it may simply be an impact structure that contains radar-dark dune or mass-wasted materials. Mountains, which are heavily modified by fluvial and mass wasting processes, could have formed as the scarps of large impact features and/or by slow contraction due to global cooling and freezing of an internal ammonia-water ocean, rather than by endogenically powered orogeny. A cold and inactive interior is consistent with an internal ammonia-water ocean, which has a peritectic temperature of 173K, easily obtained in Titan by radioactive decay alone in the absence of tidal heating. Titan's orbital eccentricity should have damped if its interior is warm and dissipative; instead, its high eccentricity can be ancient if the interior is assumed to be cold and non-dissipative. Indeed, it has been suggested that Titan may be non-hydrostatic, consistent with a thick ice shell and a cold and rigid interior. We suggest that the satellite most akin to Titan may be Callisto. Like Callisto, which may have formed relatively slowly in the outer circumjovian accretion disk

  13. A physically-based integrated numerical model for flow, upland erosion, and contaminant transport in surface-subsurface systems

    Institute of Scientific and Technical Information of China (English)

    HE ZhiGuo; WU WeiMing

    2009-01-01

    This paper presents a physically-based integrated hydrologic model that can simulate the rain-fall-induced 2D surface water flow, 3D variably saturated subsurface flow, upland soil erosion and transport, and contaminant transport in the surface-subsurface system of a watershed.The model couples surface and subsurface flows based on the assumption of continuity conditions of pressure head and exchange flux at the ground, considering infiltration and evapotranspiration.The upland rill/interrill soil erosion and transport are simulated using a non-equilibrium transport model.Con-taminant transport in the integrated surface and subsurface domains is simulated using advec-tion-diffusion equations with mass changes due to sediment sorption and desorption and exchanges between two domains due to infiltration, diffusion, and bed change.The model requires no special treatments at the interface of upland areas and streams and is suitable for wetland areas and agricul-tural watersheds with shallow streams.

  14. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey; Harden, Jennifer; Maher, Kate

    2014-08-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  15. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  16. Examining Lagrangian surface transport during a coastal upwelling in the Gulf of Finland, Baltic Sea

    Science.gov (United States)

    Delpeche-Ellmann, Nicole; Mingelaitė, Toma; Soomere, Tarmo

    2017-07-01

    We employ in-situ surface drifters and satellite derived sea surface temperature data to examine the impact that an upwelling event may have on mixing and Lagrangian transport of surrounding surface waters. The test area is located near the southern coast of the Gulf of Finland where easterly winds are known to trigger intense coastal upwellings. The analysis is based on the comparison of motions of three drifters that follow the currents in the uppermost layer with a thickness of 2 m with MODIS-based sea surface temperature data and high-quality open sea wind time series. The presence of an upwelling event superseded the classic Ekman-type drift of the surface layer and considerably slowed down the average speed of surface currents in the region affected by the upwelled cold water jet and its filaments. The drifters tended to stay amidst the surrounding surface waters. The properties of mixing were evaluated using the daily rate of temperature change along several transects. The upwelled cooler water largely kept its identity during almost the entire duration of the upwelling event. Intense mixing started at a later stage of the upwelling and continued after the end of the event when the winds that have driven the entire process began to subside.

  17. Emergent Conformal Symmetry and Geometric Transport Properties of Quantum Hall States on Singular Surfaces

    Science.gov (United States)

    Can, T.; Chiu, Y. H.; Laskin, M.; Wiegmann, P.

    2016-12-01

    We study quantum Hall states on surfaces with conical singularities. We show that the electronic fluid at the cone tip possesses an intrinsic angular momentum, which is due solely to the gravitational anomaly. We also show that quantum Hall states behave as conformal primaries near singular points, with a conformal dimension equal to the angular momentum. Finally, we argue that the gravitational anomaly and conformal dimension determine the fine structure of the electronic density at the conical point. The singularities emerge as quasiparticles with spin and exchange statistics arising from adiabatically braiding conical singularities. Thus, the gravitational anomaly, which appears as a finite size correction on smooth surfaces, dominates geometric transport on singular surfaces.

  18. Flight Deck Weather Avoidance Decision Support: Implementation and Evaluation

    Science.gov (United States)

    Wu, Shu-Chieh; Luna, Rocio; Johnson, Walter W.

    2013-01-01

    Weather related disruptions account for seventy percent of the delays in the National Airspace System (NAS). A key component in the weather plan of the Next Generation of Air Transportation System (NextGen) is to assimilate observed weather information and probabilistic forecasts into the decision process of flight crews and air traffic controllers. In this research we explore supporting flight crew weather decision making through the development of a flight deck predicted weather display system that utilizes weather predictions generated by ground-based radar. This system integrates and presents this weather information, together with in-flight trajectory modification tools, within a cockpit display of traffic information (CDTI) prototype. that the CDTI features 2D and perspective 3D visualization models of weather. The weather forecast products that we implemented were the Corridor Integrated Weather System (CIWS) and the Convective Weather Avoidance Model (CWAM), both developed by MIT Lincoln Lab. We evaluated the use of CIWS and CWAM for flight deck weather avoidance in two part-task experiments. Experiment 1 compared pilots' en route weather avoidance performance in four weather information conditions that differed in the type and amount of predicted forecast (CIWS current weather only, CIWS current and historical weather, CIWS current and forecast weather, CIWS current and forecast weather and CWAM predictions). Experiment 2 compared the use of perspective 3D and 21/2D presentations of weather for flight deck weather avoidance. Results showed that pilots could take advantage of longer range predicted weather forecasts in performing en route weather avoidance but more research will be needed to determine what combinations of information are optimal and how best to present them.

  19. Fate and transport of glyphosate and aminomethylphosphonic acid in surface waters of agricultural basins

    Science.gov (United States)

    Coupe, R.H.; Kalkhoff, S.J.; Capel, P.D.; Gregoire, C.

    2012-01-01

    Background: Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is heavily used on soybeans, corn and cotton. Glyphosate is used in almost all agricultural areas of the United States, and the agricultural use of glyphosate has increased from less than 10 000 Mg in 1992 to more than 80 000 Mg in 2007. The greatest intensity of glyphosate use is in the midwestern United States, where applications are predominantly to genetically modified corn and soybeans. In spite of the increase in usage across the United States, the characterization of the transport of glyphosate and its degradate aminomethylphosphonic acid (AMPA) on a watershed scale is lacking. Results: Glyphosate and AMPA were frequently detected in the surface waters of four agricultural basins. The frequency and magnitude of detections varied across basins, and the load, as a percentage of use, ranged from 0.009 to 0.86% and could be related to three general characteristics: source strength, rainfall runoff and flow route. Conclusions: Glyphosate use in a watershed results in some occurrence in surface water; however, the watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff and a flow route that does not include transport through the soil. ?? 2011 Society of Chemical Industry.

  20. Modeling pollutant transport in overland flow over non-planar and non-homogenous infiltrating surfaces

    Institute of Scientific and Technical Information of China (English)

    Zhi-guo HE; Gokmen TAYFUR; Qi-hua RAN; Hao-xuan WENG

    2013-01-01

    Pollutant transport in overland flow over surfaces with spatially varying microtopography,roughness,and infiltration was investigated using the diffusion wave equation and transport rate-based equation.The finite volume method in space and an implicit backward difference scheme in time were employed in the numerical solution of the 2D governing equations.The developed model was first tested against an analytical solution and an experimental study involving overland flow and the associated pollutant transport,subsequently a series of numerical tests were carried out.Non-point source pollution was investigated under spatially varying microtopography,roughness,and infiltration.The simulation results showed that microtopography and roughness were the dominant factors causing significant spatial variations in solute concentration.When the spatially varying microtopography was replaced by a smooth surface,the result was an overestimation of the solute rate at the outlet of the upland.On the other hand,when the spatially varying roughness was replaced by the average roughness and spatially varying infiltration rate by the average infiltration rate,the pollutant discharge at the outlet of the upland was not significantly affected.The numerical results further showed that one cannot ignore the spatial variations of slope and roughness when investigating the local pollutant concentration distribution.

  1. The Fate and Transport of Glyphosate and AMPA into Surface Waters of Agricultural Watersheds

    Science.gov (United States)

    Coupe, R.; Kalkhoff, S.; Capel, P.; Gregoire, C.

    2010-12-01

    Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops, but is particularly heavily used on crops which are genetically modified to be glyphosate tolerant: predominately soybeans, corn, potatoes, and cotton. Glyphosate is used extensively in almost all agricultural areas of the United States, and annual application has increased from less than 10,000 Mg in 1992 to more than 80,000 Mg in 2007. The greatest areal use is in the Midwest where glyphosate is applied on genetically modified corn and soybeans. Although use is increasing, the characterization of glyphosate transport on the watershed scale is lacking. Glyphosate, and its degradate AMPA [aminomethylphosphoric acid], was frequently detected in the surface waters of four agricultural watersheds. The load as a percent of use of glyphosate ranged from 0.009 to 0.86 percent and can be related to three factors: source strength, hydrology, and flowpath. Glyphosate use within a watershed results in some occurrence in surface water at the part per billion level; however watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.

  2. Transport and dispersion of pollutants in surface impoundments: a finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  3. Preliminary Assessment of Mercury Atmosphere-Surface Exchange Parameterizations for Incorporation into Chemical Transport Models

    Science.gov (United States)

    Khan, T.; Agnan, Y.; Obrist, D.; Selin, N. E.; Urban, N. R.; Wu, S.; Perlinger, J. A.

    2015-12-01

    Inadequate representation of process-based mechanisms of exchange behavior of elemental mercury (Hg0) and decoupled treatment of deposition and emission are two major limitations of parameterizations of atmosphere-surface exchange flux commonly incorporated into chemical transport models (CTMs). Of nineteen CTMs for Hg0 exchange we reviewed (ten global, nine regional), eight global and seven regional models have decoupled treatment of Hg0 deposition and emission, two global models include no parameterization to account for emission, and the remaining two regional models include coupled deposition and emission parameterizations (i.e., net atmosphere-surface exchange). The performance of atmosphere-surface exchange parameterizations in CTMs depends on parameterization uncertainty (in terms of both accuracy and precision) and feasibility of implementation. We provide a comparison of the performance of three available parameterizations of net atmosphere-surface exchange. To evaluate parameterization accuracy, we compare predicted exchange fluxes to field measurements conducted over a variety of surfaces compiled in a recently developed global database of terrestrial Hg0 surface-atmosphere exchange flux measurements. To assess precision, we estimate the sensitivity of predicted fluxes to the imprecision in parameter input values, and compare this sensitivity to that derived from analysis of the global Hg0 flux database. Feasibility of implementation is evaluated according to the availability of input parameters, computational requirements, and the adequacy of uncertainty representation. Based on this assessment, we provide suggestions for improved treatment of Hg0 net exchange processes in CTMs.

  4. Effects of magnetic drift tangential to magnetic surfaces on neoclassical transport in non-axisymmetric plasmas

    CERN Document Server

    Matsuoka, Seikichi; Kanno, Ryutaro; Sugama, Hideo

    2015-01-01

    In evaluating neoclassical transport by radially-local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic drift on the local neoclassical transport are investigated. To retain the effect of the tangential magnetic drift in the local treatment of neoclassical transport, a new local formulation for the drift kinetic simulation is developed. The compressibility of the phase-space volume caused by the tangential magnetic drift is regarded as a source term for the drift kinetic equation, which is solved by using a two-weight $\\delta f$ Monte Carlo method for non-Hamiltonian system [G. Hu and J. A. Krommes, Phys. Plasmas $\\rm \\textbf{1}$, 863 (1994)]. It is demonstrated that the effect of the drift is negligible for the neoclassical transport in tokamaks. In non-axisymmetric systems, however, the tangential magnetic drift substantially changes the dependence of the neoclassical transpo...

  5. Surface oxygen vacancy and oxygen permeation flux limits of perovskite ion transport membranes

    KAUST Repository

    Hunt, Anton

    2015-09-01

    © 2015 Elsevier B.V. The mechanisms and quantitative models for how oxygen is separated from air using ion transport membranes (ITMs) are not well understood, largely due to the experimental complexity for determining surface exchange reactions at extreme temperatures (>800°C). This is especially true when fuels are present at the permeate surface. For both inert and reactive (fuels) operations, solid-state oxygen surface vacancies (δ) are ultimately responsible for driving the oxygen flux, JO2. In the inert case, the value of δ at either surface is a function of the local PO2 and temperature, whilst the magnitude of δ dictates both the JO2 and the inherent stability of the material. In this study values of δ are presented based on experimental measurements under inert (CO2) sweep: using a permeation flux model and local PO2 measurements, collected by means of a local gas-sampling probe in our large-scale reactor, we can determine δ directly. The ITM assessed was La0.9Ca0.1FeO3-δ (LCF); the relative resistances to JO2 were quantified using the pre-defined permeation flux model and local PO2 values. Across a temperature range from 825°C to 1056°C, δ was found to vary from 0.007 to 0.029 (<1%), safely within material stability limits, whilst the permeate surface exchange resistance dominates. An inert JO2 limit was identified owing to a maximum sweep surface δ, δmaxinert. The physical presence of δmaxinert is attributed to a rate limiting step shift from desorption to associative electron transfer steps on the sweep surface as PO2 is reduced. Permeate surface exchange limitations under non-reactive conditions suggest that reactive (fuel) operation is necessary to accelerate surface chemistry for future work, to reduce flux resistance and push δpast δmaxinert in a stable manner.

  6. The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

    Science.gov (United States)

    Steffensen Schmidt, Louise; Aðalgeirsdóttir, Guðfinna; Guðmundsson, Sverrir; Langen, Peter L.; Pálsson, Finnur; Mottram, Ruth; Gascoin, Simon; Björnsson, Helgi

    2017-07-01

    A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980-2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs) from the period 2001-2014, as well as in situ SMB measurements from the period 1995-2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995-2014) shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981-2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes currently not accounted for in RCMs

  7. The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

    Directory of Open Access Journals (Sweden)

    L. S. Schmidt

    2017-07-01

    Full Text Available A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980–2014, is used to estimate the evolution of the glacier surface mass balance (SMB. This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs from the period 2001–2014, as well as in situ SMB measurements from the period 1995–2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995–2014 shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981–2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes

  8. The effects of surface aging on nanoparticle fate and transport in natural and engineered porous media

    Science.gov (United States)

    Mittelman, Anjuliee M.

    Nanomaterials will be subjected to various surface transformations in the environment and within water and wastewater treatment systems. A comprehensive understanding of the fate and transport behavior of "aged" nanomaterials in both natural and engineered porous media is required in order to accurately quantify ecological and human health risks. This research sought to (1) evaluate the impact of ultraviolet (UV) light aging on nanoparticle transport in water-saturated porous media; and (2) assess the effects of influent water quality on silver nanoparticle retention and dissolution in ceramic water filters. Additionally, the value of quartz crystal microbalance (QCM-D) data in nanoparticle fate and transport studies was evaluated by comparing deposition behavior in complementary QCM-D and sand columns experiments. Silver (nAg) and iron oxide nanoparticles exposed to UV light were up to 50% more strongly retained in porous media compared with freshly prepared suspensions due to less negative surface charge and larger aggregate sizes. UV-aged nAg were more prone to dissolution in sand columns, resulting in effluent Ag+ concentrations as high as 1.2 mg/L. In ceramic water filters, dissolution and cation exchange processes controlled silver release into treated water. The use of acidic, high salinity, or high hardness water accelerated oxidative dissolution of the silver coating and resulted in effluent silver concentrations 5-10 times above international drinking water guidelines. Results support the recommendation for a regular filter replacement or silver re-application schedule to ensure ongoing efficacy. Taken in concert, these research findings suggest that oxidative aging of nanomaterial surfaces (either through exposure to UV light or aggressive water chemistries) will alter the fate of nanomaterials in the environment and may decrease the effective lifetime of devices which utilize nanotechnology. Corresponding QCM-D and column experiments revealed that

  9. Electrostatic potential variation on the flux surface and its impact on impurity transport

    CERN Document Server

    García-Regaña, J M; Turkin, Y; Kleiber, R; Helander, P; Maaßberg, H; Alonso, J A; Velasco, J L

    2015-01-01

    The particle transport of impurities in magnetically confined plasmas under some conditions does not find, neither quantitatively nor qualitatively, a satisfactory theory-based explanation. This compromise the successful realization of thermo-nuclear fusion for energy production since its accumulation is known to be one of the causes that leads to the plasma breakdown. In standard reactor-relevant conditions this accumulation is in most stellarators intrinsic to the lack of toroidal symmetry, that leads to the neoclassical electric field to point radially inwards. This statement, that the standard theory allows to formulate, has been contradicted by some experiments that showed weaker or no accumulation under such conditions \\cite{Ida_pop_16_056111_2009, Yoshinuma_nf_49_062002_2009}. The charge state of the impurities makes its transport more sensitive to the electric fields. Thus, the short length scale turbulent electrostatic potential or its long wave-length variation on the flux surface $\\Phi_{1}$ -- that...

  10. High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician

    Science.gov (United States)

    Porada, Philipp; Lenton, Tim; Pohl, Alexandre; Weber, Bettina; Mander, Luke; Donnadieu, Yannick; Beer, Christian; Pöschl, Ulrich; Kleidon, Axel

    2017-04-01

    Early non-vascular vegetation in the Late Ordovician may have strongly increased chemical weathering rates of surface rocks at the global scale. This could have led to a drawdown of atmospheric CO2 and, consequently, a decrease in global temperature and an interval of glaciations. Under current climatic conditions, usually field or laboratory experiments are used to quantify enhancement of chemical weathering rates by non-vascular vegetation. However, these experiments are constrained to a small spatial scale and a limited number of species. This complicates the extrapolation to the global scale, even more so for the geological past, where physiological properties of non-vascular vegetation may have differed from current species. Here we present a spatially explicit modelling approach to simulate large-scale chemical weathering by non-vascular vegetation in the Late Ordovician. For this purpose, we use a process-based model of lichens and bryophytes, since these organisms are probably the closest living analogue to Late Ordovician vegetation. The model explicitly represents multiple physiological strategies, which enables the simulated vegetation to adapt to Ordovician climatic conditions. We estimate productivity of Ordovician vegetation with the model, and relate it to chemical weathering by assuming that the organisms dissolve rocks to extract phosphorus for the production of new biomass. Thereby we account for limits on weathering due to reduced supply of unweathered rock material in shallow regions, as well as decreased transport capacity of runoff for dissolved weathered material in dry areas. We simulate a potential global weathering flux of 2.8 km3 (rock) per year, which we define as volume of primary minerals affected by chemical transformation. Our estimate is around 3 times larger than today's global chemical weathering flux. Furthermore, chemical weathering rates simulated by our model are highly sensitive to atmospheric CO2 concentration, which implies

  11. Phosphorus transport with runoff of simulated rainfall from purple-soil cropland of different surface conditions

    Institute of Scientific and Technical Information of China (English)

    GAO Yang; ZHANG Jin-zhong; ZHU Bo; ZHOU Pei; MIAO Chi-yuan; WANG Tao

    2008-01-01

    We investigated the patterns of phosphorus transport from purple-soil cropland of 5° and 10° slopes with bare and vegetated surfaces, respectively. Each type of land was tested under a simulated moderate rainfall of 0.33 mm/min, a downfall of 0.90 mm/min, and a rainstorm of 1.86 mm/min. Runoff dynamics and changes in the export amount of phosphorus are influenced by the rainfall intensity, the slope and surface conditions of cropland. The vegetation diverts rain water from the surface into soil and helps the formation of a subsurface runoff, but has little influence on runoff process at the same sloping degree. Vegetated soil has a smaller phosphorous loss, particularly much less in the particulate form. A heavier rainfall flushes away more phosphorous. Rainwater percolating soil carries more dissolved phosphorous than particulate phosphorous. Understanding the patterns of phosphorous transport under various conditions from purple soil in the middle of Sichuan basin is helpful for developing countermeasures against non-point-source pollution resulting in the eutrophication of water bodies in this region that could, if not controlled properly, deteriorate the water quality of the Three Gorges Reservoir.

  12. A propagating ATPase gradient drives transport of surface-confined cellular cargo.

    Science.gov (United States)

    Vecchiarelli, Anthony G; Neuman, Keir C; Mizuuchi, Kiyoshi

    2014-04-01

    The faithful segregation of duplicated genetic material into daughter cells is critical to all organisms. In many bacteria, the segregation of chromosomes involves transport of "centromere-like" loci over the main body of the chromosome, the nucleoid, mediated by a two-protein partition system: a nonspecific DNA-binding ATPase, ParA, and an ATPase stimulator, ParB, which binds to the centromere-like loci. These systems have previously been proposed to function through a filament-based mechanism, analogous to actin- or microtubule-based movement. Here, we reconstituted the F-plasmid partition system using a DNA-carpeted flow cell as an artificial nucleoid surface and magnetic beads coated with plasmid partition complexes as surface-confined cargo. This minimal system recapitulated directed cargo motion driven by a surface ATPase gradient that propagated with the cargo. The dynamics are consistent with a diffusion-ratchet model, whereby the cargo dynamically establishes, and interacts with, a concentration gradient of the ATPase. A chemophoresis force ensues as the cargo perpetually chases the ATPase gradient, allowing the cargo to essentially "surf" the nucleoid on a continuously traveling wave of the ATPase. Demonstration of this non-filament-based motility mechanism in a biological context establishes a distinct class of motor system used for the transport and positioning of large cellular cargo.

  13. Rayleigh surface waves, phonon mode conversion, and thermal transport in nanostructures

    Science.gov (United States)

    Maurer, Leon; Knezevic, Irena

    We study the effects of phonon mode conversion and Rayleigh (surface) waves on thermal transport in nanostructures. We present a technique to calculate thermal conductivity in the elastic-solid approximation: a finite-difference time-domain (FDTD) solution of the elastic or scalar wave equations combined with the Green-Kubo formula. The technique is similar to an equilibrium molecular dynamics simulation, captures phonon wave behavior, and scales well to nanostructures that are too large to simulate with many other techniques. By imposing fixed or free boundary conditions, we can selectively turn off mode conversion and Rayleigh waves to study their effects. In the example case of graphenelike nanoribbons with rough edges, we find that mode conversion among bulk modes has little effect on thermal transport, but that conversion between bulk and Rayleigh waves can significantly reduce thermal conductivity. With increasing surface disorder, Rayleigh waves readily become trapped by the disorder and draw energy away from the propagating bulk modes, which lowers thermal conductivity. We discuss the implications on the accuracy of popular phonon-surface scattering models that stem from scalar wave equations and cannot capture mode conversion to Rayleigh waves.

  14. What Supergranule Flow Models Tell Us About the Sun's Surface Shear Layer and Magnetic Flux Transport

    Science.gov (United States)

    Hathaway, David

    2011-01-01

    Models of the photospheric flows due to supergranulation are generated using an evolving spectrum of vector spherical harmonics up to spherical harmonic wavenumber l1500. Doppler velocity data generated from these models are compared to direct Doppler observations from SOHO/MDI and SDO/HMI. The models are adjusted to match the observed spatial power spectrum as well as the wavenumber dependence of the cell lifetimes, differential rotation velocities, meridional flow velocities, and relative strength of radial vs. horizontal flows. The equatorial rotation rate as a function of wavelength matches the rotation rate as a function of depth as determined by global helioseismology. This leads to the conclusions that the cellular structures are anchored at depths equal to their widths, that the surface shear layer extends to at least 70 degrees latitude, and that the poleward meridional flow decreases in amplitude and reverses direction at the base of the surface shear layer (approx.35 Mm below the surface). Using the modeled flows to passively transport magnetic flux indicates that the observed differential rotation and meridional flow of the magnetic elements are directly related to the differential rotation and meridional flow of the convective pattern itself. The magnetic elements are transported by the evolving boundaries of the supergranule pattern (where the convective flows converge) and are unaffected by the weaker flows associated with the differential rotation or meridional flow of the photospheric plasma.

  15. Large scale reactive transport of nitrate across the surface water divide

    Science.gov (United States)

    Kortunov, E.; Lu, C.; Amos, R.; Grathwohl, P.

    2016-12-01

    Groundwater pollution caused by agricultural and atmospheric inputs is a pressing issue in environmental management worldwide. Various researchers have studied different aspects of nitrate contamination since the substantial increase of the agriculture pollution in the second half of the 20th century. This study addresses large scale reactive solute transport in a typical Germany hilly landscapes in a transect crossing 2 valleys: River Neckar and Ammer. The numerical model was constructed compromising a 2-D cross-section accounting for typical fractured mudstones and unconsolidated sediments. Flow modelling showed that the groundwater divide significantly deviates from the surface water divide providing conditions for inter-valley flow and transport. Reactive transport modelling of redox-sensitive solutes (e.g. agriculture nitrate and natural sulfate, DOC, ammonium) with MIN3P was used to elucidate source of nitrate in aquifers and rivers. Since both floodplains, in the Ammer and Neckar valley contain Holocene sediments relatively high in organic carbon, agricultural nitrate is reduced therein and does not reach the groundwater. However, nitrate applied in the hillslopes underlain by fractured oxidized mudrock is transported to the high yield sand and gravel aquifer in the Neckar valley. Therefore, the model predicts that nitrate in the Neckar valley comes, to a large extent, from the neighboring Ammer valley. Moreover, nitrate observed in the rivers and drains in the Ammer valley is very likely geogenic since frequent peat layers there release ammonium which is oxidized as it enters the surface water. Such findings are relevant for land and water quality management.

  16. Importance of 3D Processes Near the Ocean's Surface for Material Transport

    Science.gov (United States)

    Ozgokmen, T. M.

    2014-12-01

    There are a number of practical problems that demand an accurate knowledge of ocean currents near the surface of the ocean. It is known that oceanic coherent features transport heat and carry out vertical exchange of biogeochemical tracers. Ocean currents can affect biological primary production, air-sea gas exchanges and global tracer budgets. Ocean currents are also important for the dispersion of substances that pose a danger to society, economy and human health. Examples of such events include algal blooms, the Fukushima nuclear plant incident in the Pacific Ocean in 2011, and repeated large oil spills in the Gulf of Mexico, namely the IXTOC in 1978 and the Deepwater Horizon event in 2010. Such incidents demand accurate answers to questions such as ``where will the pollutant go?", ``how fast will it get there?" and ``how much pollutant will arrive there?", and in some instances ``where did the pollutant come from?". The answers to these questions are critical to the allocation of limited response resources, and in determining the overall impact of the events. We will summarize the efforts by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). One of the primary objectives of CARTHE is to improve predictive modeling capability for flows near the air-sea interface. In particular, two large experiments, Grand Lagrangian Deployment (GLAD) and Surf-zone and Coastal Oil Pathways Experiment (SCOPE), coordinated with real-time modeling were instructive on processes influencing near-surface material transport. Findings on submesoscale flows as well as model deficiencies to capture processes relevant to transport will be discussed. Insight into future modeling and observational plans will be provided.

  17. Weather in Your Life.

    Science.gov (United States)

    Kannegieter, Sandy; Wirkler, Linda

    Facts and activities related to weather and meteorology are presented in this unit. Separate sections cover the following topics: (1) the water cycle; (2) clouds; (3) the Beaufort Scale for rating the speed and force of wind; (4) the barometer; (5) weather prediction; (6) fall weather in Iowa (sleet, frost, and fog); (7) winter weather in Iowa…

  18. Rainfall intensity and phosphorus source effects on phosphorus transport in surface runoff from soil trays.

    Science.gov (United States)

    Shigaki, Francirose; Sharpley, Andrew; Prochnow, Luis Ignacio

    2007-02-01

    Phosphorus runoff from agricultural fields amended with mineral fertilizers and manures has been linked to freshwater eutrophication. A rainfall simulation study was conducted to evaluate the effects of different rainfall intensities and P sources differing in water soluble P (WSP) concentration on P transport in runoff from soil trays packed with a Berks loam and grassed with annual ryegrass (Lolium multiflorum Lam.). Triple superphosphate (TSP; 79% WSP), low-grade super single phosphate (LGSSP; 50% WSP), North Carolina rock phosphate (NCRP; 0.5% WSP) and swine manure (SM; 70% WSP), were broadcast (100 kg total P ha-1) and rainfall applied at 25, 50 and 75 mm h-1 1, 7, 21, and 56 days after P source application. The concentration of dissolved reactive (DRP), particulate (PP), and total P (TP) was significantly (Prunoff with a rainfall intensity of 75 than 25 mm h-1 for all P sources. Further, runoff DRP increased as P source WSP increased, with runoff from a 50 mm h-1 rain 1 day after source application having a DRP concentration of 0.25 mg L-1 for NCRP and 28.21 mg L-1 for TSP. In contrast, the proportion of runoff TP as PP was greater with low (39% PP for NCRP) than high WSP sources (4% PP for TSP) averaged for all rainfall intensities. The increased PP transport is attributed to the detachment and transport of undissolved P source particles during runoff. These results show that P source water solubility and rainfall intensity can influence P transport in runoff, which is important in evaluating the long-term risks of P source application on P transport in surface runoff.

  19. Coupling of morphology to surface transport in ion-beam-irradiated surfaces: normal incidence and rotating targets

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Garcia, Javier [Grupo Interdisciplinar de Sistemas Complejos (GISC) and School of Mathematical Sciences and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Cuerno, Rodolfo [Departamento de Matematicas and GISC, Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes (Spain); Castro, Mario [GISC and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de IngenierIa (ICAI), Universidad Pontificia Comillas de Madrid, E-28015 Madrid (Spain)], E-mail: javiermunozgarcia@gmail.com, E-mail: cuerno@math.uc3m.es, E-mail: mariocastro73@gmail.com

    2009-06-03

    Continuum models have proved their applicability to describe nanopatterns produced by ion-beam sputtering of amorphous or amorphizable targets at low and medium energies. Here we pursue the recently introduced 'hydrodynamic approach' in the cases of bombardment at normal incidence, or of oblique incidence onto rotating targets, known to lead to self-organized arrangements of nanodots. Our approach stresses the dynamical roles of material (defect) transport at the target surface and of local redeposition. By applying results previously derived for arbitrary angles of incidence, we derive effective evolution equations for these geometries of incidence, which are then numerically studied. Moreover, we show that within our model these equations are identical (albeit with different coefficients) in both cases, provided surface tension is isotropic in the target. We thus account for the common dynamics for both types of incidence conditions, namely formation of dots with short-range order and long-wavelength disorder, and an intermediate coarsening of dot features that improves the local order of the patterns. We provide for the first time approximate analytical predictions for the dependence of stationary dot features (amplitude and wavelength) on phenomenological parameters, that improve upon previous linear estimates. Finally, our theoretical results are discussed in terms of experimental data.

  20. A charge transport study in diamond, surface passivated by high-k dielectric oxides

    Energy Technology Data Exchange (ETDEWEB)

    Kovi, Kiran Kumar, E-mail: KiranKumar.Kovi@angstrom.uu.se; Majdi, Saman; Gabrysch, Markus; Isberg, Jan [Division for Electricity, Department of Engineering Sciences, Box 534, Uppsala University, Uppsala SE-751 21 (Sweden)

    2014-11-17

    The recent progress in the growth of high-quality single-crystalline diamond films has sparked interest in the realization of efficient diamond power electronic devices. However, finding a suitable passivation is essential to improve the reliability and electrical performance of devices. In the current work, high-k dielectric materials such as aluminum oxide and hafnium oxide were deposited by atomic layer deposition on intrinsic diamond as a surface passivation layer. The hole transport properties in the diamond films were evaluated and compared to unpassivated films using the lateral time-of-flight technique. An enhancement of the near surface hole mobility in diamond films of up to 27% is observed when using aluminum oxide passivation.

  1. A Controlled Field Pilot for Testing Near Surface CO2 Detection Techniques and Transport Models

    Science.gov (United States)

    Spangler, L. H.; Dobeck, L.

    2007-12-01

    A field facility has been developed to allow controlled studies of near surface CO2transport and detection technologies. The key component of the facility is a shallow horizontal, well slotted over 70m of its length and divided into seven zones via packers with mass flow control in each individual zone. The scale and fluxes were designed to address large scale CO2 storage projects and desired retention rates for those projects and those design parameters will be discussed. A wide variety of detection techniques were deployed by collaborators from Los Alamos National Lab, Lawrence Berkeley National Lab, the National Energy Technology Lab, Pacific Northwest National Lab, Lawrence Livermore National Lab and West Virginia University. Techniques included eddy covariance, soil gas measurements, hyperspectral imaging for plant stress detection, differential absorption LIDAR (both free space atmospheric and below surface soil gas), tracer studies, water sampling, stable isotope studies, and soil flux chambers. An overview of these results will be presented.

  2. Observed and modeled surface Lagrangian transport between coastal regions in the Adriatic Sea with implications for marine protected areas

    Science.gov (United States)

    Carlson, Daniel F.; Griffa, Annalisa; Zambianchi, Enrico; Suaria, Giuseppe; Corgnati, Lorenzo; Magaldi, Marcello G.; Poulain, Pierre-Marie; Russo, Aniello; Bellomo, Lucio; Mantovani, Carlo; Celentano, Paolo; Molcard, Anne; Borghini, Mireno

    2016-04-01

    Surface drifters and virtual particles are used to investigate transport between seven coastal regions in the central and southern Adriatic Sea to estimate the degree to which these regions function as a network. Alongshore coastal currents and cyclonic gyres are the primary circulation features that connected regions in the Adriatic Sea. The historical drifter observations span 25 years and, thus, provide estimates of transport between regions realized by the mean surface circulation. The virtual particle trajectories and a dedicated drifter experiment show that southeasterly Sirocco winds can drive eastward cross-Adriatic transport from the Italian coast near the Gargano Promontory to the Dalmatian Islands in Croatia. Southeasterly winds disrupt alongshore transport on the west coast. Northwesterly Mistral winds enhanced east-to-west transport and resulted in stronger southeastward coastal currents in the western Adriatic current (WAC) and export to the northern Ionian Sea. The central Italian regions showed strong connections from north to south, likely realized by alongshore transport in the WAC. Alongshore, downstream transport was weaker on the east coast, likely due to the more complex topography introduced by the Dalmatian Islands of Croatia. Cross-Adriatic connection percentages were higher for east-to-west transport. Cross-Adriatic transport, in general, occurred via the cyclonic sub-gyres, with westward (eastward) transport observed in the northern (southern) arms of the central and southern gyres.

  3. WRF-Fire: coupled weather-wildland fire modeling with the weather research and forecasting model

    Science.gov (United States)

    Janice L. Coen; Marques Cameron; John Michalakes; Edward G. Patton; Philip J. Riggan; Kara M. Yedinak

    2012-01-01

    A wildland fire behavior module (WRF-Fire) was integrated into the Weather Research and Forecasting (WRF) public domain numerical weather prediction model. The fire module is a surface fire behavior model that is two-way coupled with the atmospheric model. Near-surface winds from the atmospheric model are interpolated to a finer fire grid and used, with fuel properties...

  4. Bulk and surface electron transport in topological insulator candidate YbB{sub 6-δ}

    Energy Technology Data Exchange (ETDEWEB)

    Glushkov, Vladimir V.; Demishev, Sergey V.; Sluchanko, Nikolay E. [Prokhorov General Physics Institute of RAS, Vavilov str. 38, 119991, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudny, Moscow Region (Russian Federation); Bozhko, Alexey D.; Bogach, Alexey V.; Semeno, Alexey V.; Voronov, Valeriy V. [Prokhorov General Physics Institute of RAS, Vavilov str. 38, 119991, Moscow (Russian Federation); Dukhnenko, Anatoliy V.; Filipov, Volodimir B.; Shitsevalova, Natalya Yu. [Frantsevich Institute for Problems of Materials Science NAS, Krzhyzhanovsky str. 3, 03680, Kiev (Ukraine); Kondrin, Mikhail V. [Vereshchagin Institute of High Pressure Physics of RAS, 142190, Troitsk, Moscow (Russian Federation); Kuznetsov, Alexey V.; Sannikov, Ilia I. [National Research Nuclear University ' ' MEPhI' ' , Kashirskoe Shosse 31, 115409, Moscow (Russian Federation)

    2016-04-15

    We report the study of transport and magnetic properties of the YbB{sub 6-δ}single crystals grown by inductive zone melting. A strong disparity in the low temperature resistivity, Seebeck and Hall coefficients is established for the samples with the different level of boron deficiency. The effective parameters of the charge transport in YbB{sub 6-δ} are shown to depend on the concentration of intrinsic defects, which is estimated to range from 0.09% to 0.6%. The pronounced variation of Hall mobility μ{sub H} found for bulk holes is induced by the decrease of transport relaxation time from τ ∼ 7.7 fs for YbB{sub 5.994} to τ ∼ 2.2 fs for YbB{sub 5.96}. An extra contribution to conductivity from electrons with μ{sub H}∼ -1000 cm{sup 2} V{sup -1} s{sup -1} and the very low concentration n /n{sub Yb}∼ 10{sup -6} discovered below 20 K for all the single crystals under investigation is suggested to arise from the surface electron states appeared in the inversion layer due to the band bending. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Surface transport and stable trapping of particles and cells by an optical waveguide loop.

    Science.gov (United States)

    Hellesø, Olav Gaute; Løvhaugen, Pål; Subramanian, Ananth Z; Wilkinson, James S; Ahluwalia, Balpreet Singh

    2012-09-21

    Waveguide trapping has emerged as a useful technique for parallel and planar transport of particles and biological cells and can be integrated with lab-on-a-chip applications. However, particles trapped on waveguides are continuously propelled forward along the surface of the waveguide. This limits the practical usability of the waveguide trapping technique with other functions (e.g. analysis, imaging) that require particles to be stationary during diagnosis. In this paper, an optical waveguide loop with an intentional gap at the centre is proposed to hold propelled particles and cells. The waveguide acts as a conveyor belt to transport and deliver the particles/cells towards the gap. At the gap, the diverging light fields hold the particles at a fixed position. The proposed waveguide design is numerically studied and experimentally implemented. The optical forces on the particle at the gap are calculated using the finite element method. Experimentally, the method is used to transport and trap micro-particles and red blood cells at the gap with varying separations. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip, e.g. microfluidics or optical detection, to make an on-chip system for single cell analysis and to study the interaction between cells.

  6. Methodologies for Removing/Desorbing and Transporting Particles from Surfaces to Instrumentation

    Science.gov (United States)

    Miller, Carla J.; Cespedes, Ernesto R.

    2012-12-01

    Explosive trace detection (ETD) continues to be a key technology supporting the fight against terrorist bombing threats. Very selective and sensitive ETD instruments have been developed to detect explosive threats concealed on personnel, in vehicles, in luggage, and in cargo containers, as well as for forensic analysis (e.g. post blast inspection, bomb-maker identification, etc.) in a broad range of homeland security, law enforcement, and military applications. A number of recent studies have highlighted the fact that significant improvements in ETD systems' capabilities will be achieved, not by increasing the selectivity/sensitivity of the sensors, but by improved techniques for particle/vapor sampling, pre-concentration, and transport to the sensors. This review article represents a compilation of studies focused on characterizing the adhesive properties of explosive particles, the methodologies for removing/desorbing these particles from a range of surfaces, and approaches for transporting them to the instrument. The objectives of this review are to summarize fundamental work in explosive particle characterization, to describe experimental work performed in harvesting and transport of these particles, and to highlight those approaches that indicate high potential for improving ETD capabilities.

  7. Temporal and Spatial Characterization of Macondo 252 Signatures in Gulf of Mexico Shelf and Slope Sediments: Evidence for Weathering, Biodegradation, and Transport

    Science.gov (United States)

    Woodruff, O. P.; Yeager, K. M.; Wade, T.; Louchouarn, P.; Bonner, S.; Rutledge, M. H.

    2014-12-01

    The long-term fate of hydrocarbons in the Gulf of Mexico (GOMx) following the 2010 Deepwater Horizon oil spill has yet to be fully characterized. Elemental (% C and % N), stable isotopes (δ13Corganic), and polycyclic aromatic hydrocarbon (PAH) molecular signatures were investigated in shelf and slope sediments collected in October 2010 and 2011 to gain insight into processes affecting the distribution and fate of spilled Macondo oil. Particulate organic carbon (POC) ranged between 1.55 and 2.22 wt. % in 2010, and between 0.55 and 2.06 % in 2011, while the corresponding δ13Corganic ranges were from -23.37 to -20.77 ‰ (vs. PDB (Pee Dee Belemnite)) in 2010, and -22.68 to -20.75 ‰ (vs. PDB) in 2011. Ranges of total polycyclic aromatic hydrocarbon (TPAH) concentrations were from 72.57 to 7,543.53 ng/g in 2010 and 25.55 to 16,582.77 ng/g in 2011.The significant findings of this study are: a) sediments in 2010 and 2011 both display a deviation from the background signature of GOMx seafloor sediments through elevated POC concentrations, elevated OC:N ratios, depleted δ13Corganic, elevated TPAH concentrations, and a PAH signature dominated by petrogenic source materials, b) sediments collected 19 months after the Deepwater Horizon event display evidence of biodegraded and weathered oil, through decreased POC concentrations and OC:N, enriched δ13Corganic values, decreased TPAH concentrations, and alkyl homologue distributions characteristic of a biodegraded or weathered petrogenic source of PAHs, and c) physical processes that have distributed Macondo oil as indicated by the strong relationship of δ13Corganic (in 2010 and 2011) with longitude, in accordance with previous investigations that have characterized a west, southwest trending subsurface hydrocarbon plume that extended west from the Macondo well.

  8. Medium-range fire weather forecasts

    Science.gov (United States)

    J.O. Roads; K. Ueyoshi; S.C. Chen; J. Alpert; F. Fujioka

    1991-01-01

    The forecast skill of theNational Meteorological Center's medium range forecast (MRF) numerical forecasts of fire weather variables is assessed for the period June 1,1988 to May 31,1990. Near-surface virtual temperature, relative humidity, wind speed and a derived fire weather index (FWI) are forecast well by the MRF model. However, forecast relative humidity has...

  9. Influence of near-surface blisters on deuterium transport in tungsten

    Science.gov (United States)

    Bauer, J.; Schwarz-Selinger, T.; Schmid, K.; Balden, M.; Manhard, A.; von Toussaint, U.

    2017-08-01

    The effect of near-surface blisters on deuterium transport in tungsten is studied by means of nuclear reaction analysis (NRA) and scanning electron microscopy (SEM). Gentle deuterium plasma loading of different durations and subsequent NRA depth profiling is performed in heavily pre-blistered and unblistered areas on self-damaged tungsten samples. Comparison of the deuterium depth profiles reveals a considerable reduction of the deuterium transport into the bulk due to the presence of near-surface blisters. SEM and NRA results identify the enhanced re-emission of deuterium from the sample due to open blisters as the underlying mechanism, which reduces the deuterium flux into the bulk. Based on a simple analytical hydrogen retention model, the re-emitted deuterium flux by open blisters is determined to be 80% of the implanted deuterium flux in the present conducted experiment. In addition, the deuterium flux into the bulk is reduced by 60% compared to the unblistered case. Hence the presence of blisters is not a general disadvantage in the context of retention, but can be beneficial in slowing down the build up of a certain hydrogen inventory and in reducing the permeation flux.

  10. Oceanic transport of surface meltwater from the southern Greenland ice sheet

    Science.gov (United States)

    Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

    2016-07-01

    The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamics and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

  11. ATP-binding cassette transporter controls leaf surface secretion of anticancer drug components in Catharanthus roseus.

    Science.gov (United States)

    Yu, Fang; De Luca, Vincenzo

    2013-09-24

    The Madagascar periwinkle (Catharanthus roseus) is highly specialized for the biosynthesis of many different monoterpenoid indole alkaloids (MIAs), many of which have powerful biological activities. Such MIAs include the commercially important chemotherapy drugs vinblastine, vincristine, and other synthetic derivatives that are derived from the coupling of catharanthine and vindoline. However, previous studies have shown that biosynthesis of these MIAs involves extensive movement of metabolites between specialized internal leaf cells and the leaf epidermis that require the involvement of unknown secretory processes for mobilizing catharanthine to the leaf surface and vindoline to internal leaf cells. Spatial separation of vindoline and catharanthine provides a clear explanation for the low levels of dimers that accumulate in intact plants. The present work describes the molecular cloning and functional identification of a unique catharanthine transporter (CrTPT2) that is expressed predominantly in the epidermis of young leaves. CrTPT2 gene expression is activated by treatment with catharanthine, and its in planta silencing redistributes catharanthine to increase the levels of catharanthine-vindoline drug dimers in the leaves. Phylogenetic analysis shows that CrTPT2 is closely related to a key transporter involved in cuticle assembly in plants and that may be unique to MIA-producing plant species, where it mediates secretion of alkaloids to the plant surface.

  12. Oceanic Transport of Surface Meltwater from the Southern Greenland Ice Sheet

    Science.gov (United States)

    Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

    2016-01-01

    The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamic1 and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

  13. Factors contributing to the off-target transport of pyrethroid insecticides from urban surfaces.

    Science.gov (United States)

    Jorgenson, Brant C; Wissel-Tyson, Christopher; Young, Thomas M

    2012-08-01

    Pyrethroid insecticides used in urban and suburban contexts have been found in urban creek sediments and associated with toxicity in aquatic bioassays. The objectives of this study were to evaluate the main factors contributing to the off-target transport of pyrethroid insecticides from surfaces typical of residential landscapes. Controlled rainfall simulations over concrete, bare soil, and turf plots treated individually with pyrethroid insecticides in a suspension concentrate, an emulsifiable concentrate, or a granule formulation were conducted at different rainfall intensities and different product set-time intervals. Pyrethroid mass washoff varied by several orders of magnitude between experimental treatments. Suspension concentrate product application to concrete yielded significantly greater washoff than any other treatment; granule product application to turf yielded the least washoff. Fractional losses at 10 L of runoff ranged from 25.9 to 0.011% of pyrethroid mass applied, and 10 L nominal mass losses ranged from 3970 to 0.18 μg. Mass washoff depended principally on formulation and surface type combination and, to a lesser degree, on set-time interval and rainfall intensity. Treatment effects were analyzed by ANOVA on main factors of formulation, surface type, and set time. Factor effects were not purely additive; a significant interaction between formulation and surface type was noted.

  14. Applying GIS characterizing and modeling contaminant transport in surface water at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Becker, N.M.; Van Eeckhout, E. [Los Alamos National Lab., NM (United States); David, N.A. [Environmental Res., Inst. of Michigan, Santa Fe, NM (United States); Irvine, J.M. [Environmental Res. Inst. of Michigan, Arlington, VA (United States)

    1995-10-01

    During World War II, Los Alamos, New Mexico was chosen as the site for the secret development of the first atomic bomb. The remote location in the southwestern United States was ideal for such a project. After the war, research activities continued at the Los Alamos installation, focusing on new nuclear weapons models as well as greater effectiveness and reliability of existing weapons. Due to the emphasis on nuclear and non-nuclear weapons development as well as associated nuclear research, a large inventory of radionuclides and heavy metals have been tested, expended, and disposed of in the local environment, a high plateau of tuffaceous volcanic rocks incised by deep canyons in a semi-arid climate. In recent years an intensive evaluation of the environmental, impact of weapons testing at Los Alamos and elsewhere has been undertaken. GIS system utilization and image processing of past and current data has been an important part of this evaluation. Important problems can be more easily displayed and understood using this methodology. The main objective in this paper is to illustrate how transport of depleted uranium and associated heavy metals (copper in this case) used in dynamic testing of weapons components at open air firing sites can be evaluated and visualized. In our studies, surface water has been found to be the predominant transport mechanism. We have sampled soils, sediments, fallout, runoff water and snowmelt over a number of years in order to understand contaminant transport on- and offsite. Statistical analyses of these data have assisted in our characterization of issues such as contaminant variability, spatially and temporally, as well as in development of transport rates.

  15. The Signature Sequence Region of the Human Drug Transporter Organic Anion Transporting Polypeptide 1B1 Is Important for Protein Surface Expression

    Directory of Open Access Journals (Sweden)

    Jennina Taylor-Wells

    2014-01-01

    Full Text Available The organic anion transporting polypeptides (OATPs encompass a family of membrane transport proteins responsible for the uptake of xenobiotic compounds. Human organic anion transporting polypeptide 1B1 (OATP1B1 mediates the uptake of clinically relevant compounds such as statins and chemotherapeutic agents into hepatocytes, playing an important role in drug delivery and detoxification. The OATPs have a putative 12-transmembrane domain topology and a highly conserved signature sequence (human OATP1B1: DSRWVGAWWLNFL, spanning the extracellular loop 3/TM6 boundary. The presence of three conserved tryptophan residues at the TM interface suggests a structural role for the sequence. This was investigated by site-directed mutagenesis of selected amino acids within the sequence D251E, W254F, W258/259F, and N261A. Transport was measured using the substrate estrone-3-sulfate and surface expression detected by luminometry and confocal microscopy, facilitated by an extracellular FLAG epitope. Uptake of estrone-3-sulfate and the surface expression of D251E, W254F, and W258/259F were both significantly reduced from the wild type OATP1B1-FLAG in transfected HEK293T cells. Confocal microscopy revealed that protein was produced but was retained intracellularly. The uptake and expression of N261A were not significantly different. The reduction in surface expression and intracellular protein retention indicates a structural and/or membrane localization role for these signature sequence residues in the human drug transporter OATP1B1.

  16. The Signature Sequence Region of the Human Drug Transporter Organic Anion Transporting Polypeptide 1B1 Is Important for Protein Surface Expression.

    Science.gov (United States)

    Taylor-Wells, Jennina; Meredith, David

    2014-01-01

    The organic anion transporting polypeptides (OATPs) encompass a family of membrane transport proteins responsible for the uptake of xenobiotic compounds. Human organic anion transporting polypeptide 1B1 (OATP1B1) mediates the uptake of clinically relevant compounds such as statins and chemotherapeutic agents into hepatocytes, playing an important role in drug delivery and detoxification. The OATPs have a putative 12-transmembrane domain topology and a highly conserved signature sequence (human OATP1B1: DSRWVGAWWLNFL), spanning the extracellular loop 3/TM6 boundary. The presence of three conserved tryptophan residues at the TM interface suggests a structural role for the sequence. This was investigated by site-directed mutagenesis of selected amino acids within the sequence D251E, W254F, W258/259F, and N261A. Transport was measured using the substrate estrone-3-sulfate and surface expression detected by luminometry and confocal microscopy, facilitated by an extracellular FLAG epitope. Uptake of estrone-3-sulfate and the surface expression of D251E, W254F, and W258/259F were both significantly reduced from the wild type OATP1B1-FLAG in transfected HEK293T cells. Confocal microscopy revealed that protein was produced but was retained intracellularly. The uptake and expression of N261A were not significantly different. The reduction in surface expression and intracellular protein retention indicates a structural and/or membrane localization role for these signature sequence residues in the human drug transporter OATP1B1.

  17. No-Loss Transportation of Water Droplets by Patterning a Desired Hydrophobic Path on a Superhydrophobic Surface.

    Science.gov (United States)

    Hu, Haibao; Yu, Sixiao; Song, Dong

    2016-07-26

    The directional transportation of droplets on solid surfaces is essential in a wide range of engineering applications. It is convenient to guide liquid droplets in a given direction by utilizing the gradient of wettability, by which the binding forces can be produced. In contrast to the mass-loss transportation of a droplet moving along hydrophilic paths on a horizontal superhydrophobic surface, we present no-loss transportation by fabricating a hydrophobic path on the same surface under tangential wind. In experimental exploration and theoretical analysis, the conditions of no-loss transportation of a droplet are mainly considered. We demonstrate that the lower (or upper) critical wind velocity, under which the droplet starts on the path (or is derailed from the path), is determined by the width of the path, the length of the contact area in the direction parallel to the path, the drift angle between the path and the wind direction, and the surface wettability of the pattern. Meanwhile, the no-loss transportation of water droplets along the desired path zigzagging on a superhydrophobic surface can be achieved steadily under appropriate conditions. We anticipate that such robust no-loss transportation will find an extensive range of applications.

  18. A Study of Transport and Impact Strength of Fukushima Nuclear Pollutants in the North Pacific Surface

    Institute of Scientific and Technical Information of China (English)

    FU Hongli; LI Wei; ZHANG Xuefeng; HAN Guijun; WANG Xidong; WU Xinrong; ZHANG Lianxin

    2014-01-01

    Based on the statistics of surface drifter data of 1979-2011 and the simulation of nuclear pollutant particulate move-ments simulated using high quality ocean reanalysis surface current dataset, the transport pathways and impact strength of Fuku-shima nuclear pollutants in the North Pacific have been estimated. The particulates are used to increase the sampling size and en-hance the representativeness of statistical results. The trajectories of the drifters and particulates are first examined to identify typical drifting pathways. The results show that there are three types of transport paths for nuclear pollutants at the surface: 1) most pollutant particles move eastward and are carried by the Kuroshio and Kuroshio-extension currents and reach the east side of the North Pacific after about 3.2-3.9 years;2) some particles travel with the subtropical circulation branch and reach the east coast of China after about 1.6 years according to one drifter trajectory and about 3.6 years according to particulate trajectories;3) a little of them travel with local, small scale circulations and reach the east coast of China after about 1.3-1.8 years. Based on the par-ticulates, the impact strength of nuclear pollutants at these time scales can be estimated according to the temporal variations of relative concentration combined with the radioactive decay rate. For example, Cesium-137, carried by the strong North Pacific current, mainly accumulates in the eastern North Pacific and its impact strength is 4%of the initial level at the originating Fuku-shima area after 4 years. Due to local eddies, Cesium-137 in the western North Pacific is 1%of the initial pollutant level after 1.5 years and continuously increases to 3%after 4 years. The vertical movement of radioactive pollutants is not taken into account in the present study, and the estimation accuracy would be improved by considering three-dimensional flows.

  19. Transport and fate of nitrate at the ground-water/surface-water interface

    Science.gov (United States)

    Puckett, L.J.; Zamora, C.; Essaid, H.; Wilson, J.T.; Johnson, H.M.; Brayton, M.J.; Vogel, J.R.

    2008-01-01

    Although numerous studies of hyporheic exchange and denitrification have been conducted in pristine, high-gradient streams, few studies of this type have been conducted in nutrient-rich, low-gradient streams. This is a particularly important subject given the interest in nitrogen (N) inputs to the Gulf of Mexico and other eutrophic aquatic systems. A combination of hydrologic, mineralogical, chemical, dissolved gas, and isotopic data, were used to determine the processes controlling transport and fate of NO3- in streambeds at five sites across the USA. Water samples were collected from streambeds at depths ranging from 0.3 to 3 m at three to five points across the stream and in two to five separate transects. Residence times of water ranging from 0.28 to 34.7 d m-1 in the streambeds of N-rich watersheds played an important role in allowing denitrification to decrease NO3- concentrations. Where potential electron donors were limited and residence times were short, denitrification was limited. Consequently, in spite of reducing conditions at some sites, NO3- was transported into the stream. At two of the five study sites, NO3- in surface water infiltrated the streambeds and concentrations decreased, supporting current models that NO3- would be retained in N-rich streams. At the other three study sites, hydrogeologic controls limited or prevented infiltration of surface water into the streambed, and ground-water discharge contributed to NO 3- loads. Our results also show that in these low hydrologic-gradient systems, storm and other high-flow events can be important factors for increasing surface-water movement into streambeds. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  20. Surface runoff from manured cropping systems assessed by the paired-watershed method, part 1: P, N, and sediment transport

    Science.gov (United States)

    Transport of P, N, and sediment via runoff from crop fields can contribute to degradation of surface waters. We established a paired-watershed study in central Wisconsin to evaluate surface runoff losses of nutrients, sediment, and pathogens from different manure/crop/tillage management systems for ...

  1. High resolution imaging of vadose zone transport using surface and crosswell ground penetrating radar methods

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Kenneth H.; Kowalsky, Mike B.; Peterson, John E.

    2002-11-05

    To effectively clean up many contaminated sites there is a need for information on heterogeneities at scales ranging from one centimeter to tens of meters, as these features can alter contaminant transport significantly. At the Department of Energy's Hanford, Washington site heterogeneities of interest can range from localized phenomena such as silt or gravel lenses, fractures, clastic dikes, to large-scale lithologic discontinuities. In the vadose zone it is critical to understand the parameters controlling flow. These features have been suspected of leading to funneling and fingering, additional physical mechanisms that could alter and possibly accelerate the transport of contaminants to underlying groundwater. For example, it has been observed from the studies to date that over relatively short distances there are heterogeneities in the physical structure of the porous medium and structural differences between repacked soil cores and the field site from which the materials initially came (Raymond and Shdo, 1966). Analysis of cores taken from the vadose zone (i.e., soil surface to water table) has been useful in identifying localized zones of contamination. Unfortunately, these analyses are sparse (limited to a few boreholes) and extremely expensive. The high levels of radioactivity at many of the contaminated sites increase drilling and sample costs and analysis time. Cost of drilling and core analysis for the SX tank farm has exceeded $1M per borehole (50 meter deep) for sampling. The inability to track highly mobile species through the vadose zone highlights an important need: the need for methods to describe the complete vadose zone plume and to determine processes controlling accelerated contamination of groundwater at Hanford. A combination of surface and crosswell (i.e. borehole) geophysical measurements is one means to provide this information. The main questions addressed with the radar methods in this study are: (1) What parts of the vadose zone

  2. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue - Modelling of uranium transport in the weathered zone at Koongarra (Australia). Progress report

    NARCIS (Netherlands)

    van der Weerd H; Hassanizadeh SM; Richardson-van der Poel MA; LBG

    1993-01-01

    A study of uranium transport in the Koongarra site of Alligator Rivers Uranium deposit (Australia) is carried out. The analysis of the solid phase uranium concentration measured at various depths provides a useful picture of the dispersion process. Results of this analysis seem to support the

  3. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue - Modelling of uranium transport in the weathered zone at Koongarra (Australia). Progress report

    NARCIS (Netherlands)

    van der Weerd H; Hassanizadeh SM; Richardson-van der Poel MA; LBG

    1993-01-01

    A study of uranium transport in the Koongarra site of Alligator Rivers Uranium deposit (Australia) is carried out. The analysis of the solid phase uranium concentration measured at various depths provides a useful picture of the dispersion process. Results of this analysis seem to support the hypo

  4. Onsager heat of transport of carbon dioxide at the surface of aqueous ammonia: The remarkable effect of carbamate formation

    Science.gov (United States)

    Packwood, Daniel M.; Phillips, Leon F.

    2010-11-01

    The Onsager heat of transport Q∗ has been measured for CO 2 at the surface of aqueous ammonia. The heat of transport incorporates the enthalpy of reaction of gaseous CO 2 with ammonia, adsorbed on the liquid surface, to form adsorbed ammonium carbamate, with the result that -Q∗ has the unusually large value of 180 kJ mol -1. Measurement of Q∗ for transfer of a reactive species through a surfactant monolayer is proposed as a new method of studying reactions at liquid and quasi-liquid surfaces.

  5. Surface-modified silica colloidal crystals: nanoporous films and membranes with controlled ionic and molecular transport.

    Science.gov (United States)

    Zharov, Ilya; Khabibullin, Amir

    2014-02-18

    Nanoporous membranes are important for the study of the transport of small molecules and macromolecules through confined spaces and in applications ranging from separation of biomacromolecules and pharmaceuticals to sensing and controlled release of drugs. For many of these applications, chemists need to gate the ionic and molecular flux through the nanopores, which in turn depends on the ability to control the nanopore geometry and surface chemistry. Most commonly used nanoporous membrane materials are based on polymers. However, the nanostructure of polymeric membranes is not well-defined, and their surface is hard to modify. Inorganic nanoporous materials are attractive alternatives for polymers in the preparation of nanoporous membranes. In this Account, we describe the preparation and surface modification of inorganic nanoporous films and membranes self-assembled from silica colloidal spheres. These spheres form colloidal crystals with close-packed face centered cubic lattices upon vertical deposition from colloidal solutions. Silica colloidal crystals contain ordered arrays of interconnected three dimensional voids, which function as nanopores. We can prepare silica colloidal crystals as supported thin films on various flat solid surfaces or obtain free-standing silica colloidal membranes by sintering the colloidal crystals above 1000 °C. Unmodified silica colloidal membranes are capable of size-selective separation of macromolecules, and we can surface-modify them in a well-defined and controlled manner with small molecules and polymers. For the surface modification with small molecules, we use silanol chemistry. We grow polymer brushes with narrow molecular weight distribution and controlled length on the colloidal nanopore surface using atom transfer radical polymerization or ring-opening polymerization. We can control the flux in the resulting surface-modified nanoporous films and membranes by pH and ionic strength, temperature, light, and small molecule

  6. Transport rectification in nanopores with outer membranes modified with surface charges and polyelectrolytes.

    Science.gov (United States)

    Tagliazucchi, Mario; Rabin, Yitzhak; Szleifer, Igal

    2013-10-22

    This work reports a comprehensive theoretical study of the transport-rectification properties of cylindrical nanopores with neutral inner walls and chemically modified outer membrane. The chemical species on the two outer sides of the membrane have charges of opposite sign and can be either surface-confined species (i.e., surface charges) or polyelectrolyte brushes. The advantage of this design over other types of rectifying nanopores is that it requires controlling the composition of the outer walls of the pore (which are easy to access) rather than the inner walls, thus simplifying the fabrication process. Ion-current rectification in nanopores with charged outer walls is ascribed to applied-potential-induced changes in the ionic concentration within the pore. The rectification efficiency is studied as a function of pore length, radius, surface charge and bulk electrolyte concentration. An analytical model is derived for the case of surface-confined charges that predicts the current-potential curves in very good agreement with the numerical calculations. Neutral nanopores with polyelectrolyte-modified outer walls have two distinct advantages compared to surface-charged systems: (i) they exhibit higher rectification factors due to the large charge density immobilized by the polyelectrolyte brushes, and (ii) the applied potential deforms the polyelectrolyte chains toward the oppositely charged electrode. This deformation brings the polyelectrolyte brushes into the pore in the low conductivity state and expels them from the pore in the high conductivity regime. Calculations of the potentials of mean-force suggest that the applied-field-induced conformational changes can be used to control the translocation of cargoes larger than ions, such as proteins and nanoparticles.

  7. Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

    Science.gov (United States)

    Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

    2010-05-01

    Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model

  8. Mass Transport in Surface Diffusion of van der Waals Bonded Systems: Boosted by Rotations?

    Science.gov (United States)

    Hedgeland, Holly; Sacchi, Marco; Singh, Pratap; McIntosh, Andrew J; Jardine, Andrew P; Alexandrowicz, Gil; Ward, David J; Jenkins, Stephen J; Allison, William; Ellis, John

    2016-12-01

    Mass transport at a surface is a key factor in heterogeneous catalysis. The rate is determined by excitation across a translational barrier and depends on the energy landscape and the coupling to the thermal bath of the surface. Here we use helium spin-echo spectroscopy to track the microscopic motion of benzene adsorbed on Cu(001) at low coverage (θ ∼ 0.07 ML). Specifically, our combined experimental and computational data determine both the absolute rate and mechanism of the molecular motion. The observed rate is significantly higher by a factor of 3.0 ± 0.1 than is possible in a conventional, point-particle model and can be understood only by including additional molecular (rotational) coordinates. We argue that the effect can be described as an entropic contribution that enhances the population of molecules in the transition state. The process is generally relevant to molecular systems and illustrates the importance of the pre-exponential factor alongside the activation barrier in studies of surface kinetics.

  9. Orf virus interferes with MHC class I surface expression by targeting vesicular transport and Golgi

    Directory of Open Access Journals (Sweden)

    Rohde Jörg

    2012-07-01

    Full Text Available Abstract Background The Orf virus (ORFV, a zoonotic Parapoxvirus, causes pustular skin lesions in small ruminants (goat and sheep. Intriguingly, ORFV can repeatedly infect its host, despite the induction of a specific immunity. These immune modulating and immune evading properties are still unexplained. Results Here, we describe that ORFV infection of permissive cells impairs the intracellular transport of MHC class I molecules (MHC I as a result of structural disruption and fragmentation of the Golgi apparatus. Depending on the duration of infection, we observed a pronounced co-localization of MHC I and COP-I vesicular structures as well as a reduction of MHC I surface expression of up to 50%. These subversion processes are associated with early ORFV gene expression and are accompanied by disturbed carbohydrate trimming of post-ER MHC I. The MHC I population remaining on the cell surface shows an extended half-life, an effect that might be partially controlled also by late ORFV genes. Conclusions The presented data demonstrate that ORFV down-regulates MHC I surface expression in infected cells by targeting the late vesicular export machinery and the structure and function of the Golgi apparatus, which might aid to escape cellular immune recognition.

  10. Surface-to-mountaintop transport characterised by radon observations at the Jungfraujoch

    Directory of Open Access Journals (Sweden)

    A. D. Griffiths

    2014-07-01

    Full Text Available Atmospheric composition measurements at Jungfraujoch are affected intermittently by thermally-driven (anabatic mountain winds as well as by other vertical transport mechanisms. Using radon-222 observations, and a new analysis method, we quantify the land surface influence hour-by-hour and detect the presence of anabatic winds on a daily basis. During 2010–2011, anabatic winds occurred on roughly 40% of days, but only from April–September. Anabatic wind days were associated with warmer air temperatures over a large fraction of Europe and with a shift in airmass properties. Shifts were evident even when comparing the same radon concentrations, a proxy for land-surface influence. Aerosol washout, when quantified as a function of rain-rate using a radon normalisation technique, was also influenced by anabatic winds being more pronounced on non-anabatic days. Excluding the influence of anabatic winds, however, did not lead to a better definition of the unperturbed aerosol background than a definition based on radon alone, supporting the use of a radon threshold to identify periods with weak land-surface influence.

  11. Formulation effects and the off-target transport of pyrethroid insecticides from urban hard surfaces.

    Science.gov (United States)

    Jorgenson, Brant C; Young, Thomas M

    2010-07-01

    Controlled rainfall experiments utilizing drop-forming rainfall simulators were conducted to study various factors contributing to off-target transport of off-the-shelf formulated pyrethroid insecticides from concrete surfaces. Factors evaluated included active ingredient, product formulation, time between application and rainfall (set time), and rainfall intensity. As much as 60% and as little as 0.8% of pyrethroid applied could be recovered in surface runoff depending primarily on product formulation, and to a lesser extent on product set time. Resulting wash-off profiles during one-hour storm simulations could be categorized based on formulation, with formulations utilizing emulsifying surfactants rather than organic solvents resulting in unique wash-off profiles with overall higher wash-off efficiency. These higher wash-off efficiency profiles were qualitatively replicated by applying formulation-free neat pyrethroid in the presence of independently applied linear alkyl benzene sulfonate (LAS) surfactant, suggesting that the surfactant component of some formulated products may be influential in pyrethroid wash-off from urban hard surfaces.

  12. Weathering of rock 'Ginger'

    Science.gov (United States)

    1997-01-01

    One of the more unusual rocks at the site is Ginger, located southeast of the lander. Parts of it have the reddest color of any material in view, whereas its rounded lobes are gray and relatively unweathered. These color differences are brought out in the inset, enhanced at the upper right. In the false color image at the lower right, the shape of the visible-wavelength spectrum (related to the abundance of weathered ferric iron minerals) is indicated by the hue of the rocks. Blue indicates relatively unweathered rocks. Typical soils and drift, which are heavily weathered, are shown in green and flesh tones. The very red color in the creases in the rock surface correspond to a crust of ferric minerals. The origin of the rock is uncertain; the ferric crust may have grown underneath the rock, or it may cement pebbles together into a conglomerate. Ginger will be a target of future super-resolution studies to better constrain its origin.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  13. Project Weather and Water.

    Science.gov (United States)

    Hansen, Pal J. Kirkeby

    2000-01-01

    Introduces Project Weather and Water with the goal of developing and testing ideas of how to implement weather topics and water physics in an integrated way. Discusses teacher preparation, implementation, and evaluation of this project. (ASK)

  14. Pilot Weather Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviation weather reports relayed from pilots to FAA air traffic controllers or National Weather Service personnel. Elements include sky cover, turbulence, wind...

  15. Natural Weathering Exposure Station

    Data.gov (United States)

    Federal Laboratory Consortium — The Corps of Engineers' Treat Island Natural Weathering Exposure Station is a long-term natural weathering facility used to study concrete durability. Located on the...

  16. Daily Weather Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These daily weather records were compiled from a subset of stations in the Global Historical Climatological Network (GHCN)-Daily dataset. A weather record is...

  17. Winter Weather Emergencies

    Science.gov (United States)

    Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

  18. National Convective Weather Diagnostic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current convective hazards identified by the National Convective Weather Detection algorithm. The National Convective Weather Diagnostic (NCWD) is an automatically...

  19. Internet Weather Source

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Weather Service (NWS) National Telecommunications Gateway provides weather, hydrologic, and climate forecasts and warnings for the United States, its...

  20. Weather Radar Stations

    Data.gov (United States)

    Department of Homeland Security — These data represent Next-Generation Radar (NEXRAD) and Terminal Doppler Weather Radar (TDWR) weather radar stations within the US. The NEXRAD radar stations are...

  1. Transport and scavenging of Pu in surface waters of the Southern Hemisphere Oceans

    DEFF Research Database (Denmark)

    Gastaud, J.; Povinec, P.P.; Aoyama, M.

    2011-01-01

    The distribution of 239Pu in Atlantic and Indian Ocean waters about four decades after their main injection from atmospheric nuclear weapons tests is discussed. Recent data obtained in the framework of the SHOTS (Southern Hemisphere Ocean Tracer Studies) projects are evaluated and compared...... with previous investigations. Seawater samples were collected during the round the globe BEAGLE2003 (Blue Ocean Global Expedition) along the 30°S transect in the Atlantic and the 20°S transect in the Indian Ocean. The results indicate transport of surface waters labelled with 239Pu from the western North...... Pacific via the Indonesian Seas to the South Indian Ocean and then to the South Atlantic Ocean. Along the whole BEAGLE2003 sampling route, the Atlantic Ocean has the lowest 239Pu content due to its particle scavenging on the long way from the western North Pacific. On the other hand, concentrations...

  2. Using Contaminant Transport Modeling to Determine Historical Discharges at the Surface

    Science.gov (United States)

    Fogwell, T. W.

    2013-12-01

    When it is determined that a contaminated site needs to be remediated, the issue of who is going to pay for that remediation is an immediate concern. This means that there needs to be a determination of who the responsible parties are for the existing contamination. Seldom is it the case that records have been made and kept of the surface contaminant discharges. In many cases it is possible to determine the relative amount of contaminant discharge at the surface of the various responsible parties by employing a careful analysis of the history of contaminant transport through the surface, through the vadose zone, and within the saturated zone. The process begins with the development of a dynamic conceptual site model that takes into account the important features of the transport of the contaminants through the vadose zone and in the groundwater. The parameters for this model can be derived from flow data available for the site. The resulting contaminant transport model is a composite of the vadose zone transport model, together with the saturated zone (groundwater) flow model. Any calibration of the model should be carefully employed in order to avoid using information about the conclusions of the relative discharge amounts of the responsible parties in determining the calibrated parameters. Determination of the leading edge of the plume is an important first step. It is associated with the first discharges from the surface of the site. If there were several discharging parties at the same time, then it is important to establish a chemical or isotopic signature of the chemicals that were discharged. The time duration of the first discharger needs to be determined as accurately as possible in order to establish the appropriate characterization of the leading portion of the resulting plume in the groundwater. The information about the first discharger and the resulting part of the plume associated with this discharger serves as a basis for the determination of the

  3. Can Surface Flux Transport Account for the Weak Polar Field in Cycle 23?

    Science.gov (United States)

    Jiang, Jie; Cameron, Robert H.; Schmitt, Dieter; Schüssler, Manfred

    2013-06-01

    To reproduce the weak magnetic field on the polar caps of the Sun observed during the declining phase of cycle 23 poses a challenge to surface flux transport models since this cycle has not been particularly weak. We use a well-calibrated model to evaluate the parameter changes required to obtain simulated polar fields and open flux that are consistent with the observations. We find that the low polar field of cycle 23 could be reproduced by an increase of the meridional flow by 55% in the last cycle. Alternatively, a decrease of the mean tilt angle of sunspot groups by 28% would also lead to a similarly low polar field, but cause a delay of the polar field reversals by 1.5 years in comparison to the observations.

  4. Can surface flux transport account for the weak polar field in cycle 23?

    CERN Document Server

    Jiang, Jie; Schmitt, Dieter; Schuessler, Manfred

    2011-01-01

    To reproduce the weak magnetic field on the polar caps of the Sun observed during the declining phase of cycle 23 poses a challenge to surface flux transport models since this cycle has not been particularly weak. We use a well-calibrated model to evaluate the parameter changes required to obtain simulated polar fields and open flux that are consistent with the observations. We find that the low polar field of cycle 23 could be reproduced by an increase of the meridional flow by 55% in the last cycle. Alternatively, a decrease of the mean tilt angle of sunspot groups by 28% would also lead to a similarly low polar field, but cause a delay of the polar field reversals by 1.5 years in comparison to the observations.

  5. Simulation of soluble waste transport and buildup in surface waters using tracers

    Science.gov (United States)

    Kilpatrick, F.A.

    1993-01-01

    Soluble tracers can be used to simulate the transport and dispersion of soluble wastes that might have been introduced or are planned for introduction into surface waters. Measured tracer-response curves produced from the injection of a known quantity of soluble tracer can be used in conjunction with the superposition principle to simulate potential waste buildup in streams, lakes, and estuaries. Such information is particularly valuable to environmental and water-resource planners in determining the effects of proposed waste discharges. The theory, techniques, analysis, and presentation of results of tracer-waste simulation tests in rivers, lakes, and estuaries are described. This manual builds on other manuals dealing with dye tracing by emphasizing the expanded use of data from time-of-travel studies.

  6. Weathering-limited hillslope evolution in carbonate landscapes

    Science.gov (United States)

    Godard, Vincent; Ollivier, Vincent; Bellier, Olivier; Miramont, Cécile; Shabanian, Esmaeil; Fleury, Jules; Benedetti, Lucilla; Guillou, Valéry

    2016-07-01

    Understanding topographic evolution requires integrating elementary processes acting at the hillslope scale into the long-wavelength framework of landscape dynamics. Recent progress has been made in the quantification of denudation of eroding landscapes and its links with topography. Despite these advances, data is still sparse in carbonate terrain, which covers a significant part of the Earth's surface. In this study, we measured both long-term denudation rates using in situ-produced 36Cl concentrations in bedrock and regolith clasts and surface convexity at 12 sites along ridges of the Luberon carbonate range in Provence, Southeastern France. Starting from ∼30 mm/ka for the lowering of the summit plateau surface, denudation linearly increases with increasing hilltop convexity up to ∼70 mm/ka, as predicted by diffusive mass transport theory. Beyond this point denudation rates appear to be insensitive to the increase in hilltop convexity. We interpret this constant denudation as indicating a transition from a regime where hillslope evolution is primarily controlled by diffusive downslope regolith transport, toward a situation in which denudation is limited by the rate at which physical and chemical weathering processes can produce clasts and lower the hilltop. Such an abrupt transition into a weathering-limited dynamics may prevent hillslope denudation from balancing the rate of base level fall imposed by the river network and could potentially explain the development of high local relief in many Mediterranean carbonate landscapes.

  7. The power of weather

    OpenAIRE

    Christian Huurman; Francesco Ravazzolo; Chen Zhou

    2010-01-01

    This paper examines the predictive power of weather for electricity prices in day ahead markets in real time. We find that next-day weather forecasts improve the forecast accuracy of Scandinavian day-ahead electricity prices substantially in terms of point forecasts, suggesting that weather forecasts can price the weather premium. This improvement strengthens the confidence in the forecasting model, which results in high center-mass predictive densities. In density forecast, such a predictive...

  8. From the surface to the seafloor: How giant larvaceans transport microplastics into the deep sea.

    Science.gov (United States)

    Katija, Kakani; Choy, C Anela; Sherlock, Rob E; Sherman, Alana D; Robison, Bruce H

    2017-08-01

    Plastic waste is a pervasive feature of marine environments, yet little is empirically known about the biological and physical processes that transport plastics through marine ecosystems. To address this need, we conducted in situ feeding studies of microplastic particles (10 to 600 μm in diameter) with the giant larvacean Bathochordaeus stygius. Larvaceans are abundant components of global zooplankton assemblages, regularly build mucus "houses" to filter particulate matter from the surrounding water, and later abandon these structures when clogged. By conducting in situ feeding experiments with remotely operated vehicles, we show that giant larvaceans are able to filter a range of microplastic particles from the water column, ingest, and then package microplastics into their fecal pellets. Microplastics also readily affix to their houses, which have been shown to sink quickly to the seafloor and deliver pulses of carbon to benthic ecosystems. Thus, giant larvaceans can contribute to the vertical flux of microplastics through the rapid sinking of fecal pellets and discarded houses. Larvaceans, and potentially other abundant pelagic filter feeders, may thus comprise a novel biological transport mechanism delivering microplastics from surface waters, through the water column, and to the seafloor. Our findings necessitate the development of tools and sampling methodologies to quantify concentrations and identify environmental microplastics throughout the water column.

  9. Surface Flux Transport and the Evolution of the Sun's Polar Fields

    Science.gov (United States)

    Wang, Y.-M.

    2017-09-01

    The evolution of the polar fields occupies a central place in flux transport (Babcock-Leighton) models of the solar cycle. We discuss the relationship between surface flux transport and polar field evolution, focusing on two main issues: the latitudinal profile of the meridional flow and the axial tilts of active regions. Recent helioseismic observations indicate that the poleward flow speed peaks at much lower latitudes than inferred from magnetic feature tracking, which includes the effect of supergranular diffusion and thus does not represent the actual bulk flow. Employing idealized simulations, we demonstrate that flow profiles that peak at mid latitudes give rise to overly strong and concentrated polar fields. We discuss the differences between magnetic and white-light measurements of tilt angles, noting the large uncertainties inherent in the sunspot group measurements and their tendency to underestimate the actual tilts. We find no clear evidence for systematic cycle-to-cycle variations in Joy's law during cycles 21-23. Finally, based on the observed evolution of the Sun's axial dipole component and polar fields up to the end of 2015, we predict that cycle 25 will be similar in amplitude to cycle 24.

  10. Transport and retention of phosphorus in surface water in an urban slum area

    Science.gov (United States)

    Nyenje, P. M.; Meijer, L. M. G.; Foppen, J. W.; Kulabako, R.; Uhlenbrook, S.

    2013-08-01

    The transport of excessive phosphorus (P) discharged from unsewered informal settlements (slums) due to poor on-site sanitation is largely unknown. Hence, we investigated the processes governing P transport in a 28 km2 slum-dominated catchment in Kampala, Uganda. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining the catchment and from a small size tertiary channel draining one of the contributing slum areas (0.5 km2). Samples were analyzed for orthophosphate (PO4-P), particulate P (PP), total P (TP) and selected hydro-chemical parameters. Channel bed and suspended sediments were collected to determine their sorption potential, geo-available metals and dominant P forms. We found that P inputs in the catchment originated mainly from domestic wastewater as evidenced by high concentrations of Cl (36-144 mg L-1), HCO3 and other cations in the channels. Most P discharged during low flow conditions was particulate implying that much of it was retained in bed sediments. Retained P was mostly bound to Ca and Fe/Al oxides. Hence, we inferred that mineral precipitation and adsorption to Ca-minerals were the dominant P retention processes. Bed sediments were P-saturated and showed a tendency to release P to discharging waters. P released was likely due to Ca-bound P because of the strong correlation between Ca and total P in sediments (r2 = 0.9). High flows exhibited a strong flush of PP and SS implying that part of P retained was frequently flushed out of the catchment by surface erosion and resuspension of bed sediment. Our findings suggest that P accumulated in the channel bed during low flows and then was slowly released into surface water. Hence, it will likely take some time, even with improved wastewater management practices, before P loads to downstream areas can be significantly reduced.

  11. Transport and retention of phosphorus in surface water in an urban slum area

    Directory of Open Access Journals (Sweden)

    P. M. Nyenje

    2013-08-01

    Full Text Available The transport of excessive phosphorus (P discharged from unsewered informal settlements (slums due to poor on-site sanitation is largely unknown. Hence, we investigated the processes governing P transport in a 28 km2 slum-dominated catchment in Kampala, Uganda. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h from a primary channel draining the catchment and from a small size tertiary channel draining one of the contributing slum areas (0.5 km2. Samples were analyzed for orthophosphate (PO4-P, particulate P (PP, total P (TP and selected hydro-chemical parameters. Channel bed and suspended sediments were collected to determine their sorption potential, geo-available metals and dominant P forms. We found that P inputs in the catchment originated mainly from domestic wastewater as evidenced by high concentrations of Cl (36–144 mg L-1, HCO3 and other cations in the channels. Most P discharged during low flow conditions was particulate implying that much of it was retained in bed sediments. Retained P was mostly bound to Ca and Fe/Al oxides. Hence, we inferred that mineral precipitation and adsorption to Ca-minerals were the dominant P retention processes. Bed sediments were P-saturated and showed a tendency to release P to discharging waters. P released was likely due to Ca-bound P because of the strong correlation between Ca and total P in sediments (r2 = 0.9. High flows exhibited a strong flush of PP and SS implying that part of P retained was frequently flushed out of the catchment by surface erosion and resuspension of bed sediment. Our findings suggest that P accumulated in the channel bed during low flows and then was slowly released into surface water. Hence, it will likely take some time, even with improved wastewater management practices, before P loads to downstream areas can be significantly reduced.

  12. Cell surface receptors for signal transduction and ligand transport: a design principles study.

    Directory of Open Access Journals (Sweden)

    Harish Shankaran

    2007-06-01

    Full Text Available Receptors constitute the interface of cells to their external environment. These molecules bind specific ligands involved in multiple processes, such as signal transduction and nutrient transport. Although a variety of cell surface receptors undergo endocytosis, the systems-level design principles that govern the evolution of receptor trafficking dynamics are far from fully understood. We have constructed a generalized mathematical model of receptor-ligand binding and internalization to understand how receptor internalization dynamics encodes receptor function and regulation. A given signaling or transport receptor system represents a particular implementation of this module with a specific set of kinetic parameters. Parametric analysis of the response of receptor systems to ligand inputs reveals that receptor systems can be characterized as being: i avidity-controlled where the response control depends primarily on the extracellular ligand capture efficiency, ii consumption-controlled where the ability to internalize surface-bound ligand is the primary control parameter, and iii dual-sensitivity where both the avidity and consumption parameters are important. We show that the transferrin and low-density lipoprotein receptors are avidity-controlled, the vitellogenin receptor is consumption-controlled, and the epidermal growth factor receptor is a dual-sensitivity receptor. Significantly, we show that ligand-induced endocytosis is a mechanism to enhance the accuracy of signaling receptors rather than merely serving to attenuate signaling. Our analysis reveals that the location of a receptor system in the avidity-consumption parameter space can be used to understand both its function and its regulation.

  13. Dew architectures - Dew annouces the good weather

    OpenAIRE

    Beysens, Daniel; Broggini, Filippo; Milimouk-Melnytchouk, Iryna; Ouazzani, Jalil; Tixier, Nicolas

    2012-01-01

    International audience; Dew is a natural phenomenon that occurs under particular weather conditions (clear nocturnal sky, humid air, low wind) and on a surface specially designed for this purpose (high radiative cooling properties, special architectural design). Depending on the weather conditions and the surface characteristics, the water yield can give up to 0.7 litres per square meter and per night. Although the collection of rain water on roof turns out to be relatively simple, dew harves...

  14. Effects of noradrenaline on the cell-surface glucose transporters in cultured brown adipocytes: novel mechanism for selective activation of GLUT1 glucose transporters.

    Science.gov (United States)

    Shimizu, Y; Satoh, S; Yano, H; Minokoshi, Y; Cushman, S W; Shimazu, T

    1998-01-01

    Glucose transport into rat brown adipocytes has been shown to be stimulated directly by the sympathetic neurotransmitter, noradrenaline, without a significant increase in the protein content of either GLUT1 or GLUT4 glucose transporter in the plasma membrane [Shimizu, Kielar, Minokoshi and Shimazu (1996) Biochem. J. 314, 485-490]. In the present study, we labelled the exofacial glucose-binding sites of GLUT1 and GLUT4 with a membrane-impermeant photoaffinity reagent, 2-N-[4-(1-azitrifluoroethyl)benzoyl]-[2-3H]1,3-bis- (D-mannos-4-yloxy)-2-propylamine (ATB-[3H]BMPA), to determine which isoform is responsible for the noradrenaline-induced increase in glucose transport into intact brown adipocytes in culture. Insulin stimulated the rate of hexose transport by increasing ATB-[3H]BMPA-labelled cell-surface GLUT4. In contrast, the noradrenaline-induced increase in glucose transport was not accompanied by an increased ATB-[3H]BMPA labelling of GLUT4, nor with an increased amount of GLUT4 in the plasma membrane fraction as assessed by Western blotting, indicating that noradrenaline does not promote the translocation of GLUT4. However, noradrenaline induced an increase in photoaffinity labelling of cell-surface GLUT1 without an apparent increase in the immunoreactive GLUT1 protein in the plasma membrane. This is suggestive of an increased affinity of GLUT1 for the ligand. In fact, the Ki value of non-radioactive ATB-BMPA for 2-deoxy-D-glucose uptake was significantly decreased after treatment of the cells with noradrenaline. The increased photoaffinity labelling of GLUT1 and increased glucose transport caused by noradrenaline were inhibited by a cAMP antagonist, cAMP-S Rp-isomer. These results demonstrate that noradrenaline stimulates glucose transport in brown adipocytes by enhancing the functional activity of GLUT1 through a cAMP-dependent mechanism. PMID:9461536

  15. Weather Fundamentals: Meteorology. [Videotape].

    Science.gov (United States)

    1998

    The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) looks at how meteorologists gather and interpret current weather data collected from sources…

  16. Cold-Weather Sports

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Cold-Weather Sports KidsHealth > For Teens > Cold-Weather Sports A A A What's in this article? ... Equipment Ahh, winter! Shorter days. Frigid temperatures. Foul weather. What better time to be outdoors? Winter sports ...

  17. Weather Conditions, Weather Information and Car Crashes

    Directory of Open Access Journals (Sweden)

    Adriaan Perrels

    2015-11-01

    Full Text Available Road traffic safety is the result of a complex interaction of factors, and causes behind road vehicle crashes require different measures to reduce their impacts. This study assesses how strongly the variation in daily winter crash rates associates with weather conditions in Finland. This is done by illustrating trends and spatiotemporal variation in the crash rates, by showing how a GIS application can evidence the association between temporary rises in regional crash rates and the occurrence of bad weather, and with a regression model on crash rate sensitivity to adverse weather conditions. The analysis indicates that a base rate of crashes depending on non-weather factors exists, and some combinations of extreme weather conditions are able to substantially push up crash rates on days with bad weather. Some spatial causation factors, such as variation of geophysical characteristics causing systematic differences in the distributions of weather variables, exist. Yet, even in winter, non-spatial factors are normally more significant. GIS data can support optimal deployment of rescue services and enhance in-depth quantitative analysis by helping to identify the most appropriate spatial and temporal resolutions. However, the supportive role of GIS should not be inferred as existence of highly significant spatial causation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Glenn Charles [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    In this dissertation, results are presented of laboratory investigations and mathematical modeling efforts designed to better understand the interactions of ozone with surfaces. In the laboratory, carpet and duct materials were exposed to ozone and measured ozone uptake kinetics and the ozone induced emissions of volatile organic compounds. To understand the results of the experiments, mathematical methods were developed to describe dynamic indoor aldehyde concentrations, mass transport of reactive species to smooth surfaces, the equivalent reaction probability of whole carpet due to the surface reactivity of fibers and carpet backing, and ozone aging of surfaces. Carpets, separated carpet fibers, and separated carpet backing all tended to release aldehydes when exposed to ozone. Secondary emissions were mostly n-nonanal and several other smaller aldehydes. The pattern of emissions suggested that vegetable oils may be precursors for these oxidized emissions. Several possible precursors and experiments in which linseed and tung oils were tested for their secondary emission potential were discussed. Dynamic emission rates of 2-nonenal from a residential carpet may indicate that intermediate species in the oxidation of conjugated olefins can significantly delay aldehyde emissions and act as reservoir for these compounds. The ozone induced emission rate of 2-nonenal, a very odorous compound, can result in odorous indoor concentrations for several years. Surface ozone reactivity is a key parameter in determining the flux of ozone to a surface, is parameterized by the reaction probability, which is simply the probability that an ozone molecule will be irreversibly consumed when it strikes a surface. In laboratory studies of two residential and two commercial carpets, the ozone reaction probability for carpet fibers, carpet backing and the equivalent reaction probability for whole carpet were determined. Typically reaction probability values for these materials were 10

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

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Glenn C.

    1999-12-01

    In this dissertation, results are presented of laboratory investigations and mathematical modeling efforts designed to better understand the interactions of ozone with surfaces. In the laboratory, carpet and duct materials were exposed to ozone and measured ozone uptake kinetics and the ozone induced emissions of volatile organic compounds. To understand the results of the experiments, mathematical methods were developed to describe dynamic indoor aldehyde concentrations, mass transport of reactive species to smooth surfaces, the equivalent reaction probability of whole carpet due to the surface reactivity of fibers and carpet backing, and ozone aging of surfaces. Carpets, separated carpet fibers, and separated carpet backing all tended to release aldehydes when exposed to ozone. Secondary emissions were mostly n-nonanal and several other smaller aldehydes. The pattern of emissions suggested that vegetable oils may be precursors for these oxidized emissions. Several possible precursors and experiments in which linseed and tung oils were tested for their secondary emission potential were discussed. Dynamic emission rates of 2-nonenal from a residential carpet may indicate that intermediate species in the oxidation of conjugated olefins can significantly delay aldehyde emissions and act as reservoir for these compounds. The ozone induced emission rate of 2-nonenal, a very odorous compound, can result in odorous indoor concentrations for several years. Surface ozone reactivity is a key parameter in determining the flux of ozone to a surface, is parameterized by the reaction probability, which is simply the probability that an ozone molecule will be irreversibly consumed when it strikes a surface. In laboratory studies of two residential and two commercial carpets, the ozone reaction probability for carpet fibers, carpet backing and the equivalent reaction probability for whole carpet were determined. Typically reaction probability values for these materials were 10

  20. Theoretical investigation of the electronic structure and quantum transport in the graphene-C(111) diamond surface system.

    Science.gov (United States)

    Selli, Daniele; Baburin, Igor; Leoni, Stefano; Zhu, Zhen; Tománek, David; Seifert, Gotthard

    2013-10-30

    We investigate the interaction of a graphene monolayer with the C(111) diamond surface using ab initio density functional theory. To accommodate the lattice mismatch between graphene and diamond, the overlayer deforms into a wavy structure that binds strongly to the diamond substrate. The detached ridges of the wavy graphene overlayer behave electronically as free-standing polyacetylene chains with delocalized π electrons, separated by regions containing only sp(3) carbon atoms covalently bonded to the (111) diamond surface. We performed quantum transport calculations for different geometries of the system to study how the buckling of the graphene layer and the associated bonding to the diamond substrate affect the transport properties. The system displays high carrier mobility along the ridges and a wide transport gap in the direction normal to the ridges. These intriguing, strongly anisotropic transport properties qualify the hybrid graphene-diamond system as a viable candidate for electronic nanodevices.

  1. A model for the biosynthesis and transport of plasma membrane-associated signaling receptors to the cell surface

    Directory of Open Access Journals (Sweden)

    Sorina Claudia Popescu

    2012-04-01

    Full Text Available Intracellular protein transport is emerging as critical in determining the outcome of receptor-activated signal transduction pathways. In plants, relatively little is known about the nature of the molecular components and mechanisms involved in coordinating receptor synthesis and transport to the cell surface. Recent advances in this field indicate that signaling pathways and intracellular transport machinery converge and coordinate to render receptors competent for signaling at their plasma membrane activity sites. The biogenesis and transport to the cell surface of signaling receptors appears to require both general trafficking and receptor-specific factors. Several molecular determinants, residing or associated with compartments of the secretory pathway and known to influence aspects in receptor biogenesis, are discussed and integrated into a predictive cooperative model for the functional expression of signaling receptors at the plasma membrane.

  2. Transport of Dirac fermions on the surface of strong topological insulator and graphene

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Arijit

    2012-06-14

    In this dissertation I study electronic transport through Dirac Fermions on the surface of strong topological insulator and graphene. I start by reviewing the physics of topological insulator and graphene and the low energy effective theory for the electronic states of the surface of a 3D strong topological insulator and graphene. Using this theory the electronic structure of the surface states of strong topological insulators of geometries with large surface to bulk ratio like nanowire and thin film are obtained. Then the energy spectrum and the spin-parity structure of the eigenstates for a finite size topological insulator quantum dot of the shape of a nanotube are considered. Numerical calculations show that even at the lowest energy scales, the ''spin-surface locking'' is broken, that is, the spin direction in a topologically protected surface mode is not locked to the surface. The calculations also show the existence of ''zero-momentum'' modes, and sub-gap states localized near the ''caps'' of the dot. Both the energy spectrum and the spin texture of the eigenstates are basically reproduced from an analytical surface Dirac fermion description. The results are compared to microscopic calculations using a tight-binding model for a strong topological insulator in a finite-length nanowire geometry, which shows qualitative similarity. Then, a theoretical study of electron-phonon scattering effects in thin films made of a strong topological insulator is presented. Phonons are modeled by isotropic elastic continuum theory with stress-free boundary conditions, and the interaction with the helical surface Dirac fermions is mediated by the deformation potential. The temperature-dependent electrical resistivity ρ(T) and the quasi-particle decay rate Γ(T) observable in photo-emission are computed numerically. The low and high-temperature power laws for both quantities are obtained analytically. Detailed

  3. Spatio-Temporal Modelling of Dust Transport over Surface Mining Areas and Neighbouring Residential Zones

    Directory of Open Access Journals (Sweden)

    Eva Gulikova

    2008-06-01

    Full Text Available Projects focusing on spatio-temporal modelling of the living environment need to manage a wide range of terrain measurements, existing spatial data, time series, results of spatial analysis and inputs/outputs from numerical simulations. Thus, GISs are often used to manage data from remote sensors, to provide advanced spatial analysis and to integrate numerical models. In order to demonstrate the integration of spatial data, time series and methods in the framework of the GIS, we present a case study focused on the modelling of dust transport over a surface coal mining area, exploring spatial data from 3D laser scanners, GPS measurements, aerial images, time series of meteorological observations, inputs/outputs form numerical models and existing geographic resources. To achieve this, digital terrain models, layers including GPS thematic mapping, and scenes with simulation of wind flows are created to visualize and interpret coal dust transport over the mine area and a neighbouring residential zone. A temporary coal storage and sorting site, located near the residential zone, is one of the dominant sources of emissions. Using numerical simulations, the possible effects of wind flows are observed over the surface, modified by natural objects and man-made obstacles. The coal dust drifts with the wind in the direction of the residential zone and is partially deposited in this area. The simultaneous display of the digital map layers together with the location of the dominant emission source, wind flows and protected areas enables a risk assessment of the dust deposition in the area of interest to be performed. In order to obtain a more accurate simulation of wind flows over the temporary storage and sorting site, 3D laser scanning and GPS thematic mapping are used to create a more detailed digital terrain model. Thus, visualization of wind flows over the area of interest combined with 3D map layers enables the exploration of the processes of coal dust

  4. Mechanisms of nanoparticle internalization and transport across an intestinal epithelial cell model: effect of size and surface charge.

    Science.gov (United States)

    Bannunah, Azzah M; Vllasaliu, Driton; Lord, Jennie; Stolnik, Snjezana

    2014-12-01

    This study investigated the effect of nanoparticle size (50 and 100 nm) and surface charge on their interaction with Caco-2 monolayers as a model of the intestinal epithelium, including cell internalization pathways and the level of transepithelial transport. Initially, toxicity assays showed that cell viability and cell membrane integrity were dependent on the surface charge and applied mass, number, and total surface area of nanoparticles, as tested in two epithelial cell lines, colon carcinoma Caco-2 and airway Calu-3. This also identified suitable nanoparticle concentrations for subsequent cell uptake experiments. Nanoparticle application at doses below half maximal effective concentration (EC₅₀) revealed that the transport efficiency (ratio of transport to cell uptake) across Caco-2 cell monolayers is significantly higher for negatively charged nanoparticles compared to their positively charged counterparts (of similar size), despite the higher level of internalization of positively charged systems. Cell internalization pathways were hence probed using a panel of pharmacological inhibitors aiming to establish whether the discrepancy in transport efficiency is due to different uptake and transport pathways. Vesicular trans-monolayer transport for both positively and negatively charged nanoparticles was confirmed via inhibition of dynamin (by dynasore) and microtubule network (via nocodazole), which significantly reduced the transport of both nanoparticle systems. For positively charged nanoparticles a significant decrease in internalization and transport (46% and 37%, respectively) occurred in the presence of a clathrin pathway inhibitor (chlorpromazine), macropinocytosis inhibition (42%; achieved by 5-(N-ethyl-N-isopropyi)-amiloride), and under cholesterol depletion (38%; via methyl-β-cyclodextrin), but remained unaffected by the inhibition of lipid raft associated uptake (caveolae) by genistein. On the contrary, the most prominent reduction in

  5. Thermal transport study across interface “nanostructured solid surface / fluid” by photoacoustic technique

    Science.gov (United States)

    Voitenko, K.; Isaiev, M.; Pastushenko, A.; Andrusenko, D.; Kuzmich, A.; Lysenko, V.; Burbelo, R.

    2017-01-01

    In the paper the experimental study of heat transport across the interface “porous silicon/liquid” by photoacoustic technique is reported. Two cases with and without liquid covering of porous silicon surface were considered. Thermal perturbations were excited at the surface of porous silicon as a result of absorption of the light with modulated intensity. The resulting thermal-elastic stresses arising in the system were registered with piezoelectric transducer. The amplitude-frequency dependencies of the voltage on the piezoelectric electrodes were measured. The presence of the liquid film leads to decreasing of the amplitude of photoacoustic signal as a result of the thermal energy evacuation from the porous silicon into the liquid. The experimental dependencies were fitted with the results of simulation that takes into account heat fluxes separation at the porous silicon/liquid interface. With the presented method one can precisely measure heat fluxes transferred from the solid into contacting fluid. Moreover, the presented approach can be easily adopted for the thermal conductivity study of the different nanofluids as well as thermal resistance at the interface nanostructured solid/fluid.

  6. Weatherization and Intergovernmental Program - Weatherization Assistance Program

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-06-01

    The U.S. Department of Energy’s (DOE) Weatherization Assistance Program reduces energy costs for low-income households by increasing the energy efficiency of their homes, while ensuring their health and safety.

  7. Surface States Transport in Topological Insulator Bi_{0.83}Sb_{0.17} Nanowires

    Science.gov (United States)

    Konopko, L. A.; Nikolaeva, A. A.; Huber, T. E.; Ansermet, J.-P.

    2016-12-01

    We investigate the transport properties of topological insulator (TI) Bi_{0.83}Sb_{0.17} nanowires. Single-crystal nanowire samples with diameters ranging from 75 nm to 1.1 μ m are prepared using high frequency liquid phase casting in a glass capillary; cylindrical single crystals with (10bar{1}1) orientation along the wire axis are produced. Bi_{0.83}Sb_{0.17} is a narrow-gap semiconductor with an energy gap at the L point of the Brillouin zone, Δ E = 21 meV. The resistance of the samples increases with decreasing temperature, but a decrease in resistance is observed at low temperatures. This effect is a clear manifestation of TI properties (i.e., the presence of a highly conducting zone on the TI surface). When the diameter of the nanowire decreases, the energy gap Δ E grows as 1 / d (for diameter d = 1.1 μ m and d =75 nm Δ E = 21 and 45 meV, respectively), which proves the presence of the quantum size effect in these samples. We investigate the magnetoresistance of Bi_{0.83}Sb_{0.17} nanowires at various magnetic field orientations. Shubnikov-de Haas oscillations are observed in Bi_{0.83}Sb_{0.17} nanowires at T = 1.5 K, demonstrating the existence of high mobility (μ_S = 26{,}700-47{,}000 cm^2V^{-1}s^{-1}) two-dimensional (2D) carriers in the surface areas of the nanowires, which are nearly perpendicular to the C_3 axis. From the linear dependence of the nanowire conductance on nanowire diameter at T = 4.2 K, the square resistance R_sq of the surface states of the nanowires is obtained (R_sq =70 Ohm).

  8. Phonon transport in silicon nanowires: The reduced group velocity and surface-roughness scattering

    Science.gov (United States)

    Zhu, Liyan; Li, Baowen; Li, Wu

    2016-09-01

    Using a linear-scaling Kubo simulation approach, we have quantitatively investigated the effects of confinement and surface roughness on phonon transport in silicon nanowires (SiNWs) as thick as 55 nm in diameter R . The confinement effect leads to significant reduction of phonon group velocity v in SiNWs compared to bulk silicon except at extremely low phonon frequencies f , which very likely persists in SiNWs several hundreds of nanometers thick, suggesting the inapplicability of bulk properties, including anharmonic phonon scattering, to SiNWs. For instance, the velocity can be reduced by more than 30% for phonons with f >4.5 THz in 55-nm-thick nanowires. In rough SiNWs Casimir's limit, which is valid in confined macroscopic systems, can underestimate the surface scattering by more than one order of magnitude. For a roughness profile with Lorentzian correlation characterized by root-mean-square roughness σ and correlation length Lr, the frequency-dependent phonon diffusivity D follows power-law dependences D ∝Rασ-βLrγ , where α ˜2 and β ˜1 . On average, γ increases from 0 to 0.5 as R /σ increases. The mean free path and the phonon lifetime essentially follow the same power-law dependences. These dependences are in striking contrast to Casimir's limit, i.e., D ˜v R /3 , and manifest the dominant role of the change in the number of atoms due to roughness. The thermal conductivity κ can vary by one order of magnitude with varying σ and Lr in SiNWs, and increasing σ and shortening Lr can efficiently lower κ below Casimir's limit by one order of magnitude. Our work provides different insights to understand the ultralow thermal conductivity of SiNWs reported experimentally and guidance to manipulate κ via surface roughness engineering.

  9. 膨胀土渠道坡面风化特征及处理措施探讨%Weathering characteristics of slope surface of expansive soil canal and treatment measures

    Institute of Scientific and Technical Information of China (English)

    强鲁斌; 麻斌; 薛永明; 倪柱柱

    2014-01-01

    After slope excavation of expansive soil canal, the soil body at slope surface would suffer weathering destruction of different degree due to the long-time exposure. If the protection and treatment for weathered canal slope are not taken in time, the destruction will expand and the stability of canal slope will be threatened. In view of the practical situation of deep excavation of slope of expansive soil canal of Middle Route Project of South-to-North Water Diversion, the weathering characteristics of the slope surface are analyzed, and the suggestions for its construction and excavation, protection and treatment are put forward. It is pointed out that after the excavation, modified soil should be backfilled in time. If it can not be sealed timely, the measures such as surface protection by waterproof material, setting drainage ditches and changing excavation mode should be adopted, so as to reduce or avoid the destruction of the slope surface by weathering.%膨胀土渠道边坡开挖后,若裸露时间过长,渠坡坡面土体会遭受不同程度的风化破坏。若不及时采取防护或处理,风化渠坡的破坏范围会不断扩大,很有可能会危及到渠坡的稳定。结合南水北调中线深挖方膨胀土渠道开挖所揭露的实际情况,对渠坡坡面风化特征进行了分析,并提出了膨胀土渠坡施工开挖、防护及处理措施。着重指出,渠道开挖后应及时回填改性土封闭,对于不能及时封闭的坡面,可采取防雨材料覆盖、设置排水沟、改变开挖方式等,避免或减小坡面土体遭受风化破坏的风险。

  10. Weathering and vegetation effects in early stages of soil formation

    Science.gov (United States)

    Jonathan D. Phillips; Alice V. Turkington; Daniel A. Marion

    2008-01-01

    Bedrock surfaces in the Ouachita Mountains, Arkansas, exposed by spillway construction and which had not previously been subjected to surface weathering environments, developed 15?20 cm thick soil covers in less than three decades. All open bedrock joints showed evidence of weathering and biological activity. Rock surfaces and fragments also showed evidence of...

  11. Surface-Water to Groundwater Transport of Pharmaceuticals in a Wastewater-Impacted Stream in the U.S.

    Science.gov (United States)

    Bradley, P. M.; Barber, L. B.; Duris, J. W.; Foreman, W. T.; Furlong, E. T.; Hubbard, L. E.; Hutchinson, K. J.; Keefe, S. H.; Kolpin, D. W.

    2014-12-01

    Wastewater pharmaceutical contamination of shallow groundwater is a substantial concern in effluent-dominated streams, due to aqueous mobility and designed bioactivity of pharmaceuticals and due to effluent-driven hydraulic gradients. Improved understanding of the environmental fate and transport of wastewater-derived pharmaceuticals is essential for effective protection of vital aquatic ecosystem services, environmental health, and drinking-water supplies. Substantial longitudinal (downstream) transport of pharmaceutical contaminants has been documented in effluent-impacted streams. The comparative lack of information on vertical and lateral transport (infiltration) of wastewater contaminants from surface-water to hyporheic and shallow groundwater compartments is a critical scientific data gap, given the potential for contamination of groundwater supplies in effluent-impacted systems. Growing dependencies on bank filtration and artificial recharge applications for release of wastewater to the environment and for pretreatment of poor-quality surface-water for drinking water emphasize the critical need to better understand the exchange of wastewater contaminants, like pharmaceuticals, between surface-water and groundwater compartments. The potential transport of effluent-derived pharmaceutical contaminants from surface-water to hyporheic-water and shallow groundwater compartments was examined in a wastewater-treatment-facility (WWTF) impacted stream in Ankeny, Iowa under effluent-dominated (71-99% of downstream flow) conditions. Strong hydraulic gradients and hydrologic connectivity were evident between surface-water and shallow-groundwater compartments in the vicinity of the WWTF outfall. Carbamazepine, sulfamethoxazole, and immunologically-related compounds were detected in groundwater 10-20 meters from the stream bank. Direct aqueous-injection HPLC-MS/MS revealed high percentage detections of pharmaceuticals (110 total analytes) in surface-water and groundwater

  12. Application of divided convective-dispersive transport model to simulate conservative transport processes in planted horizontal sub-surface flow constructed wetlands.

    Science.gov (United States)

    Dittrich, Ernő; Klincsik, Mihály

    2015-11-01

    We have created a divided convective-dispersive transport (D-CDT) model that can be used to provide an accurate simulation of conservative transport processes in planted horizontal sub-surface flow constructed wetlands filled with coarse gravel (HSFCW-C). This model makes a fitted response curve from the sum of two independent CDT curves, which show the contributions of the main and side streams. The analytical solutions of both CDT curves are inverse Gaussian distribution functions. We used Fréchet distribution to provide a fast optimization mathematical procedure. As a result of our detailed analysis, we concluded that the most important role in the fast upward part of the tracer response curve is played by the main stream, with high porous velocity and dispersion. This gives the first inverse Gaussian distribution function. The side stream shows slower transport processes in the micro-porous system, and this shows the impact of back-mixing and dead zones, too. The significance of this new model is that it can simulate transport processes in this kind of systems more accurately than the conventionally used convective-dispersive transport (CDT) model. The calculated velocity and dispersion coefficients with the D-CDT model gave differences of 24-54% (of velocity) and 22-308% (of dispersion coeff.) from the conventional CDT model, and were closer to actual hydraulic behaviour.

  13. Influence of surface wettability on transport mechanisms governing water droplet evaporation.

    Science.gov (United States)

    Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

    2014-08-19

    Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ≲ 60°), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ≲ CA ≲ 90°), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ≳ 90°), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ≥ 90°) when evaporative cooling is strong and the

  14. Contributions of regional and intercontinental transport to surface ozone in Tokyo

    Science.gov (United States)

    Yoshitomi, M.; Wild, O.; Akimoto, H.

    2011-04-01

    Japan lies downwind of the Asian continent and for much of the year air quality is directly influenced by emissions of ozone precursors over these heavily-populated and rapidly-industrializing regions. This study examines the extent to which oxidant transport from regional and distant anthropogenic sources influences air quality in Japan in springtime, when these contributions are largest. We find that European and North American contributions to surface ozone over Japan in spring are persistent, averaging 3.5±1.1 ppb and 2.8±0.5 ppb respectively, and are greatest in cold continental outflow conditions following the passage of cold fronts. Contributions from China are larger, 4.0±2.8 ppb, and more variable, as expected for a closer source region, and are generally highest near cold fronts preceding the influence of more distant sources. The stratosphere provides a varying but ever-present background of ozone of about 11.2±2.5 ppb during spring. Local sources over Japan and Korea have a relatively small impact on mean ozone, 2.4±7.6 ppb, but this masks a strong diurnal signal, and local sources clearly dominate during episodes of high daytime ozone. By examining the meteorological mechanisms that favour transport from different source regions, we demonstrate that while maximum foreign influence generally does not occur at the same time as the greatest buildup of oxidants from local sources, it retains a significant influence under these conditions. It is thus clear that while meteorological boundaries provide some protection from foreign influence during oxidant outbreaks in Tokyo, these distant sources still make a substantial contribution to exceedance of the Japanese ozone air quality standard in springtime.

  15. Contributions of regional and intercontinental transport to surface ozone in the Tokyo area

    Science.gov (United States)

    Yoshitomi, M.; Wild, O.; Akimoto, H.

    2011-08-01

    Japan lies downwind of the Asian continent and for much of the year air quality is directly influenced by emissions of ozone precursors over these heavily-populated and rapidly-industrializing regions. This study examines the extent to which oxidant transport from regional and distant anthropogenic sources influences air quality in Japan in springtime, when these contributions are largest. We find that European and North American contributions to surface ozone over Japan in spring are persistent, averaging 3.5±1.1 ppb and 2.8±0.5 ppb respectively, and are greatest in cold continental outflow conditions following the passage of cold fronts. Contributions from China are larger, 4.0±2.8 ppb, and more variable, as expected for a closer source region, and are generally highest near cold fronts preceding the influence of more distant sources. The stratosphere provides a varying but ever-present background of ozone of about 11.2±2.5 ppb during spring. Local sources over Japan and Korea have a relatively small impact on mean ozone, 2.4±7.6 ppb, but this masks a strong diurnal signal, and local sources clearly dominate during episodes of high daytime ozone. By examining the meteorological mechanisms that favour transport from different source regions, we demonstrate that while maximum foreign influence generally does not occur at the same time as the greatest buildup of oxidants from local sources, it retains a significant influence under these conditions. It is thus clear that while meteorological boundaries provide some protection from foreign influence during oxidant outbreaks in Tokyo, these distant sources still make a substantial contribution to exceedance of the Japanese ozone air quality standard in springtime.

  16. Chemical weathering trends in fine-grained ephemeral stream sediments of the McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Marra, Kristen R.; Elwood Madden, Megan E.; Soreghan, Gerilyn S.; Hall, Brenda L.

    2017-03-01

    We investigated chemical weathering trends within the fine-grained ( 40 m2/g. Utilization of MFW (mafic-felsic-weathered) and A-CN-K (Al2O3-CaO + Na2O-K2O) plots, however, are more effective in discerning the extent and nature of chemical weathering in these stream systems. Ca and Na depletion observed within the sediments exhibiting the highest surface area in Delta Stream suggest that chemical weathering may result in pitting and/or incongruent dissolution of pyroxenes and feldspars, as well as the development of amorphous and/or nanophase weathering products. In contrast, Clark Glacier stream sediments do not have similar leaching trends in the fine-grained sediment fraction and exhibit minimal weathering overall. This may suggest that fine-grained material is being trapped on top of the Clark Glacier surface and has not yet been transported into the weathering environment of the hyporheic zone due to timing of sampling. Alternatively, complete dissolution of very fine-grained sediment could be occurring in this stream transect, and is therefore not preserved in the fine sediment fraction. Overall, the magnitude of chemical weathering observed between the two stream systems is ultimately related to the nature of the underlying drift (cold and wet-based drift deposition), dispersal patterns of eolian fines, and variable stream discharge rates. Thus, incorporation of local fine-grained sediment derived from the underlying glacial drift deposits and distributed via the varying wind regimes within the hyper-arid climate into active stream channels may facilitate incongruent mineral dissolution and development of weathering products, and ultimately influence the composition and concentration of meltwater stream solutes.

  17. A Double-Ring Algorithm for Modeling Solar Active Regions: Unifying Kinematic Dynamo Models and Surface Flux-Transport Simulations

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Martens, Petrus C H; Yeates, Anthony R

    2010-01-01

    The emergence of tilted bipolar active regions and the dispersal of their flux, mediated via processes such as diffusion, differential rotation and meridional circulation is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed $\\alpha$-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithm for modeling the Babcock-Leighton mechanism based on active region eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations we first show that an axisymmetric formulation -- which is usually invoked in kinematic dynamo models -- can reasonably approximate the surface flux dy...

  18. Transport and fate of hexachlorocyclohexanes in the oceanic air and surface seawater

    Directory of Open Access Journals (Sweden)

    Z. Xie

    2011-06-01

    Full Text Available Hexachlorocyclohexanes (HCHs are ubiquitous organic pollutants derived from pesticide application. They are subject to long-range transport, persistent in the environment, and capable of accumulation in biota. Shipboard measurements of HCH isomers (α-, γ- and β-HCH in surface seawater and boundary layer atmospheric samples were conducted in the Atlantic and the Southern Ocean in October to December of 2008. ΣHCHs concentrations (the sum of α-, γ- and β-HCH in the lower atmosphere ranged from 11.8 to 36.9 pg m−3 (mean: 26.6 ± 11.0 pg m−3 in the Northern Hemisphere (NH, and from 1.5 to 4.0 pg m−3 (mean: 2.8 ± 1.1 pg m−3 in the Southern Hemisphere (SH, respectively. Water concentrations were: α-HCH 0.33–46.8 pg l−1, γ-HCH 0.02–33.2 pg l−1 and β-HCH 0.11–2 pg l−1. HCH concentrations decreased from the North Atlantic to the Southern Ocean, indicating historical use of HCHs in the NH. Spatial distribution showed increasing concentrations from the equator towards North and South latitudes illustrating the concept of cold condensation and less interhemispheric mixing process. In comparison to concentrations measured in 1987–1999/2000, gaseous HCHs were slightly lower, while dissolved HCHs decreased by factor of 2–3 orders of magnitude. Air-water exchange gradients suggested net deposition for α-HCH (mean: 3759 pg m−2 day−1 and γ-HCH (mean: 1987 pg m−2 day−1, whereas β-HCH varied between equilibrium (volatilization: <0–12 pg m−2 day−1 and net deposition (range: 6–687 pg m−2 day−1, indicating a multi-hopper transport behavior. Climate change may significantly accelerate the releasing process of "old" HCHs from continental storage (e.g. soil, vegetation and high mountains and drive long-range transport from sources to deposition in the

  19. The effects of surface functionalization on rheology, structure and transport properties of nanocomposites

    Science.gov (United States)

    Ranka, Moulik A.

    In this thesis, the effects of surface functionalization using hydrophobic silanes on properties of nanocomposites comprising 42 nm silica particles suspended in a melt of polyethylene-glycol (PEG) are studied using rheological, static and dynamic x-ray scattering studies. The nanocomposites are studied in the low molecular weight unentangled (PEG-400) and high molecular weight entangled (PEG-20000) regimes. We find no differences in the properties of the bare and silanized particles in the low volume fraction regime up to where the interparticle separation distance h > 6Rg. In the region of 6Rg > h > 3Rg (5Rg > h > 3Rg, in case of entangled melts), we find substantial differences in the rheological, structure and transport properties when comparing the bare and silanized particles. In the unentangled melts, we observe up to four orders of magnitude drop in the viscosity of the composites at the highest levels of silanization and observe shear thinning behavior that is unlike what is universally seen for hard spheres. For the entangled melts, a yield stress is observed for the silanized particles that is absent in the case of the bare particles and there is a divergence in the elastic modulus in comparison to bare particles. We observe an anomalous speed up in the density relaxations and an associated maxima in structure properties in the case of unentangled melts which has been reported previously for particles experiencing soft repulsive potentials. A clear reentrant behavior in structure and transport properties is observed for bare particles in the entangled melts that have been previously reported for particles interacting with soft repulsive potentials such as square shoulder and ramp potentials. In the silanized systems, the density relaxation times although lower than bare particles, is ii unaffected by increasing volume fraction up to h ~ 3Rg and is decoupled from the structure properties which are non-monotonic similar to bare particles. In the region of

  20. Weather pattern climatology of the United States

    Energy Technology Data Exchange (ETDEWEB)

    Barchet, W.R.; Davis, W.E.

    1984-01-01

    In this study the geographic domain covered the 48 conterminous states of the United States. The daily synoptic weather pattern was classified into nine types for the 10-year period January 1, 1969 to December 31, 1978. Weather pattern types were defined relative to the classical polar front model of a mid-latitude cyclonic storm system and its associated air masses. Guidelines for classifying weather patterns on an operational basis were developed. These were applied to 3652 daily surface weather maps to produce a time series of weather pattern type at 120 grid points of a 160 point, 3/sup 0/ latitude by 4/sup 0/ longitude array over the United States. Statistics on the frequency of occurrence, persistence and alternation of weather patterns were calculated for each grid point. Summary statistics for the entire grid and for six regions were also presented. Frequency of occurrence and persistence were found to depend on the size and speed of movement of the weather pattern. Large, slow moving air masses had higher frequency of occurrence and longer persistence than small (fronts) or rapidly moving (or changing) features (fronts, storm centers). Some types showed distinct regional preferences. The subtropical maritime high occurred mainly in the south central and southeast. An indeterminate weather pattern type accounted for those weather patterns that did not fit the polar front model or were too disorganized to be classified. The intermountain thermal low of the desert southwest was one such feature that dominated both frequency of occurrence and persistence in this region. Alternation from one weather pattern to another followed the polar front model of a moving cyclonic storm. The tendency for anticyclonic weather patterns to become disorganized as they weakened was seen in the high percentage of these patterns that changed to an indeterminate pattern as they aged.

  1. Micromechanism of oxygen transport during initial stage oxidation in Si(100) surface: A ReaxFF molecular dynamics simulation study

    Science.gov (United States)

    Sun, Yu; Liu, Yilun; Chen, Xuefeng; Zhai, Zhi; Xu, Fei; Liu, Yijun

    2017-06-01

    The early stage oxidation in Si(100) surface has been investigated in this work by a reactive force field molecular dynamics (ReaxFF MD) simulation, manifesting that the oxygen transport acted as a dominant issue for initial oxidation process. Due to the oxidation, a compressive stress was generated in the oxide layer which blocked the oxygen transport perpendicular to the Si(100) surface and further prevented oxidation in the deeper layer. In contrast, thermal actuation was beneficial to the oxygen transport into deeper layer as temperature increases. Therefore, a competition mechanism was found for the oxygen transport during early stage oxidation in Si(100) surface. At room temperature, the oxygen transport was governed by the blocking effect of compressive stress, so a better quality oxide film with more uniform interface and more stoichiometric oxide structure was obtained. Indeed, the mechanism presented in this work is also applicable for other self-limiting oxidation (e.g. metal oxidation) and is helpful for the design of high-performance electronic devices.

  2. Landslides as weathering reactors; links between physical erosion and weathering in rapidly eroding mountain belts

    Science.gov (United States)

    Emberson, R.; Hovius, N.; Galy, A.

    2014-12-01

    The link between physical erosion and chemical weathering is generally modelled with a surface-blanketing weathering zone, where the supply of fresh minerals is tied to the average rate of denudation. In very fast eroding environments, however, sediment production is dominated by landsliding, which acts in a stochastic fashion across the landscape, contrasting strongly with more uniform denudation models. If physical erosion is a driver of weathering at the highest erosion rates, then an alternative weathering model is required. Here we show that landslides can be effective 'weathering reactors'. Previous work modelling the effect of landslides on chemical weathering (Gabet 2007) considered the fresh bedrock surfaces exposed in landslide scars. However, fracturing during the landslide motion generates fresh surfaces, the total surface area of which exceeds that of the exposed scar by many orders of magnitude. Moreover, landslides introduce concavity into hillslopes, which acts to catch precipitation. This is funnelled into a deposit of highly fragmented rock mass with large reactive surface area and limited hydraulic conductivity (Lo et al. 2007). This allows percolating water reaction time for chemical weathering; any admixture of macerated organic debris could yield organic acid to further accelerate weathering. In the South island of New Zealand, seepage from recent landslide deposits has systematically high solute concentrations, far outstripping concentration in runoff from locations where soils are present. River total dissolved load in the western Southern Alps is highly correlated with the rate of recent (erosion; this contrasts with persistent and ubiquitous weathering associated with soil production. Solute fluxes from fast eroding landscapes therefore likely depend on climatic or tectonic forcing of mass wasting; greater precipitation would drive increased weathering, while earthquakes, in generating landslides (Dadson et al. 2003; Chen & Hawkins 2009

  3. Fate of Uranium During Transport Across the Groundwater-Surface Water Interface

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, Peter R. [Princeton Univ., NJ (United States); Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-30

    Discharge of contaminated groundwater to surface waters is of concern at many DOE facilities. For example, at F-Area and TNX-Area on the Savannah River Site, contaminated groundwater, including uranium, is already discharging into natural wetlands. It is at this interface where contaminants come into contact with the biosphere. These this research addressed a critical knowledge gap focusing on the geochemistry of uranium (or for that matter, any redox-active contaminant) in wetland systems. Understanding the interactions between hydrological, microbial, and chemical processes will make it possible to provide a more accurate conceptual and quantitative understanding of radionuclide fate and transport under these unique conditions. Understanding these processes will permit better long-term management and the necessary technical justification for invoking Monitored Natural Attenuation of contaminated wetland areas. Specifically, this research did provide new insights on how plant-induced alterations to the sediment biogeochemical processes affect the key uranium reducing microorganisms, the uranium reduction, its spatial distribution, the speciation of the immobilized uranium, and its long-term stability. This was achieved by conducting laboratory mesocosm wetland experiments as well as field measurements at the SRNL. Results have shown that uranium can be immobilized in wetland systems. To a degree some of the soluble U(VI) was reduced to insoluble U(IV), but the majority of the immobilized U was incorporated into iron oxyhydroxides that precipitated onto the root surfaces of wetland plants. This U was immobilized mostly as U(VI). Because it was immobilized in its oxidized form, results showed that dry spells, resulting in the lowering of the water table and the exposure of the U to oxic conditions, did not result in U remobilization.

  4. Campylobacter fetus surface layer proteins are transported by a type I secretion system.

    Science.gov (United States)

    Thompson, S A; Shedd, O L; Ray, K C; Beins, M H; Jorgensen, J P; Blaser, M J

    1998-12-01

    The virulence of Campylobacter fetus, a bacterial pathogen of ungulates and humans, is mediated in part by the presence of a paracrystalline surface layer (S-layer) that confers serum resistance. The subunits of the S-layer are S-layer proteins (SLPs) that are secreted in the absence of an N-terminal signal sequence and attach to either type A or B C. fetus lipopolysaccharide in a serospecific manner. Antigenic variation of multiple SLPs (encoded by sapA homologs) of type A strain 23D occurs by inversion of a promoter-containing DNA element flanked by two sapA homologs. Cloning and sequencing of the entire 6.2-kb invertible region from C. fetus 23D revealed a probable 5.6-kb operon of four overlapping genes (sapCDEF, with sizes of 1,035, 1,752, 1,284, and 1,302 bp, respectively) transcribed in the opposite direction from sapA. The four genes also were present in the invertible region of type B strain 84-107 and were virtually identical to their counterparts in the type A strain. Although SapC had no database homologies, SapD, SapE, and SapF had predicted amino acid homologies with type I protein secretion systems (typified by Escherichia coli HlyBD/TolC or Erwinia chrysanthemi PrtDEF) that utilize C-terminal secretion signals to mediate the secretion of hemolysins, leukotoxins, or proteases from other bacterial species. Analysis of the C termini of four C. fetus SLPs revealed conserved structures that are potential secretion signals. A C. fetus sapD mutant neither produced nor secreted SLPs. E. coli expressing C. fetus sapA and sapCDEF secreted SapA, indicating that the sapCDEF genes are sufficient for SLP secretion. C. fetus SLPs therefore are transported to the cell surface by a type I secretion system.

  5. Fate and Transport of Nutrients in Groundwater and Surface Water in an Urban Slum Catchment Kampala, Uganda

    NARCIS (Netherlands)

    Nyenje, P.

    2014-01-01

    This study investigates the generation, transport and fate of sanitation-related nutrients in groundwater and surface water in an urban slum area in sub-Saharan Africa. In excess, nutrients can cause eutrophication of downstream water bodies. The study argues that nitrogen-containing rains and

  6. 50 CFR 36.12 - Use of snowmobiles, motorboats, dog teams and other means of surface transportation traditionally...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Use of snowmobiles, motorboats, dog teams... Subsistence Uses § 36.12 Use of snowmobiles, motorboats, dog teams and other means of surface transportation... provision of subchapter C of title 50 CFR the use of snowmobiles, motorboats, dog teams and other means...

  7. Fate and Transport of Nutrients in Groundwater and Surface Water in an Urban Slum Catchment Kampala, Uganda

    NARCIS (Netherlands)

    Nyenje, P.

    2014-01-01

    This study investigates the generation, transport and fate of sanitation-related nutrients in groundwater and surface water in an urban slum area in sub-Saharan Africa. In excess, nutrients can cause eutrophication of downstream water bodies. The study argues that nitrogen-containing rains and domes

  8. Reactive transport in surface sediments. II. Media: an object-oriented problem-solving environment for early diagenesis

    NARCIS (Netherlands)

    Meysman, F.J.R.; Middelburg, J.J.; Herman, P.M.J.; Heip, C.H.R.

    2003-01-01

    The MEDIA (Modelling Early DIAgenesis) software package comprises a flexible and extensible software system that provides problem-solving assistance for simulating 1D reactive transport in surface sediments. MEDIA allows multiple diagenetic models to be built by extending a model template with new m

  9. Magnetic transport apparatus for the production of ultracold atomic gases in the vicinity of a dielectric surface

    CERN Document Server

    Haendel, S; Wiles, T P; Hopkins, S A; Cornish, S L

    2011-01-01

    We present an apparatus designed for studies of atom-surface interactions using quantum degenerate gases of $^{85}$Rb and $^{87}$Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum (UHV). To maintain excellent optical access to the region surrounding the surface magnetic transport is used to deliver ultracold atoms from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the magnetic transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally we demonstrate the loading of a hybrid optical-magnetic trap with $^{87}$Rb and the creation of Bose-Einstein condensates via forced evaporative cooling ...

  10. Estrogen transport in surface runoff from agricultural fields treated with two different application methods of dairy manure

    Science.gov (United States)

    While the land-application of animal manure provides many benefits, concerns exist regarding the subsequent transport of hormones and potential effects on aquatic ecosystems. This study compares two methods of dairy manure application, surface broadcasting and shallow disk injection, on the fate and...

  11. Space weathering of asteroids

    CERN Document Server

    Shestopalov, D I; Cloutis, E A

    2012-01-01

    Analysis of laboratory experiments simulating space weathering optical effects on atmosphereless planetary bodies reveals that the time needed to alter the spectrum of an ordinary chondrite meteorite to resemble the overall spectral shape and slope of an S-type asteroid is about ~ 0.1 Myr. The time required to reduce the visible albedo of samples to ~ 0.05 is ~ 1 Myr. Since both these timescales are much less than the average collisional lifetime of asteroids larger than several kilometers in size, numerous low-albedo asteroids having reddish spectra with subdued absorption bands should be observed instead of an S-type dominated population. It is not the case because asteroid surfaces cannot be considered as undisturbed, unlike laboratory samples. We have estimated the number of collisions occurring in the time of 105 yr between asteroids and projectiles of various sizes and show that impact-activated motions of regolith particles counteract the progress of optical maturation of asteroid surfaces. Continual r...

  12. Stratification, Sediment Transport, and the Early Wet Surface of Meridiani Planum

    Science.gov (United States)

    Grotzinger, J. P.; Athena Science Team

    2004-12-01

    the spectral gap in the size distribution of eolian dunes and ripples. A further clue to the likely subaqueous origin for Eagle cross-laminae is provided by their festoon geometry which requires that the reconstructed ripples have three-dimensional geometry defined by highly sinuous crestlines. In terrestrial settings such bedforms are known only to develop in subaqueous, subcritical flows, with velocities of less than one meter per second. On Mars, the initiation of subaqueous sediment movement is expected to occur at velocities lower than on earth, by a factor of 1.34. With respect to length scales, such as bedform dimensions, the scaling factor turns out to have the opposite sense so that, given dynamically similar flows, ripples on Mars might be larger by a factor of 1.34. Neither of these rescaling effects influences the interpretation that cm-scale, festoon cross-lamination at Eagle crater most probably requires sediment transport in subaqueous, low-velocity flows across the Meridiani plains. The assemblage of primary facies recorded at Eagle crater is most consistent with an environment characterized by episodic inundation by surface water to shallow depths, followed by evaporation, and exposure and desiccation. Terrestrial analogs for such a suite of facies and surface processes include small interdune depressions, playa lakes, and sabkhas adjacent to marginal seaways. All rover observations indicate that the evaporite-bearing cross-bedded unit extends at least on the order of 1 km though MOC and THEMIS data suggest it extends much further.

  13. Upscaling of the specific surface area for reactive transport modelling in fractured rock

    Science.gov (United States)

    Cvetkovic, Vladimir

    2014-05-01

    The impact of flow heterogeneity on chemical transport from single to multiple fractures, is investigated. The emphasis is on the dynamic nature of the specific surface area (SSA) due to heterogeneity of the flow, relative to a purely geometrical definition. It is shown how to account for SSA as a random variable in modelling multi-component reactions. The flow-dependent SSA is interpreted probabilistically, following inert tracer particles along individual fractures. Upscaling to a fracture network is proposed as a time-domain random walk based on the statistics of SSA for single fractures. Statistics of SSA are investigated for three correlation structures of transmissivity, one classical multi-gaussian, and two non-Gaussian. The coefficient of variation of single fracture SSA decreases monotonously with the distance over the fracture length; the CV of the upscaled SSA reduces further such that after ca 20 fractures it is under 0.1 for a disconnected field, and around 0.2 for connected and multi-gaussian fields. This implies that after 10-20 fractures, uncertainty in SSA is significantly reduced, justifying the use of an effective value. A conservative, lower bound for the dimensionless upscaled effective SSA was found to be 1, suitable for all heterogeneity structures, assuming the cubic hydraulic law applicable.

  14. EHD-driven mass transport enhancement in surface dielectric barrier discharges

    Science.gov (United States)

    Taglioli, M.; Shaw, A.; Wright, A.; FitzPatrick, B.; Neretti, G.; Seri, P.; Borghi, C. A.; Iza, F.

    2016-12-01

    Surface dielectric barrier discharges (S-DBDs) have received renewed attention in recent years for their potential application in emerging biomedical, environmental and agricultural applications. In most of these applications, the plasma is not in direct contact with the substrate being treated and the transport of reactive species from the plasma to the substrate is typically assumed to be controlled by diffusion. Here, we demonstrate that generally this is not the case and that electrohydrodynamic (EHD) forces can produce jets that enhance the delivery of these species, thereby influencing the efficacy of the S-DBD device. In particular, we have studied the degradation of potassium indigotrisulfonate solutions exposed to S-DBDs generated in devices with annular electrodes of diameters varying between 10 mm and 50 mm. All the devices were driven at constant linear power density (watts per cm of plasma length) and although local plasma properties remained the same in all the devices, a three-fold efficacy enhancement was observed for devices of diameter ~30 mm due to EHD effects.

  15. A Review of Removable Surface Contamination on Radioactive Materials Transportation Containers

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Jr, W. E.; Watson, E. C.; Murphy, D. W.; Harrer, B. J.; Harty, R.; Aldrich, J. M.

    1981-05-01

    This report contains the results of a study sponsored by the U.S. Nuclear Regulatory Commission (NRC) of removable surface contamination on radioactive materials transportation containers. The purpose of the study is to provide information to the NRC during their review of existing regulations. Data was obtained from both industry and literature on three major topics: 1) radiation doses, 2) economic costs, and 3) contamination frequencies. Containers for four categories of radioactive materials are considered including radiopharmaceuticals, industrial sources, nuclear fuel cycle materials, and low-level radioactive waste. Assumptions made in this study use current information to obtain realistic yet conservative estimates of radiation dose and economic costs. Collective and individual radiation doses are presented for each container category on a per container basis. Total doses, to workers and the public, are also presented for spent fuel cask and low-level waste drum decontamination. Estimates of the additional economic costs incurred by lowering current limits by factors of 10 and 100 are presented. Current contamination levels for each category of container are estimated from the data collected. The information contained in this report is designed to be useful to the NRC in preparing their recommendations for new regulations.

  16. A Versatile Lifting Device for Lunar Surface Payload Handling, Inspection & Regolith Transport Operations

    Science.gov (United States)

    Doggett, William; Dorsey, John; Collins, Tim; King, Bruce; Mikulas, Martin

    2008-01-01

    Devices for lifting and transporting payloads and material are critical for efficient Earth-based construction operations. Devices with similar functionality will be needed to support lunar-outpost construction, servicing, inspection, regolith excavation, grading and payload placement. Past studies have proposed that only a few carefully selected devices are required for a lunar outpost. One particular set of operations involves lifting and manipulating payloads in the 100 kg to 3,000 kg range, which are too large or massive to be handled by unassisted astronauts. This paper will review historical devices used for payload handling in space and on earth to derive a set of desirable features for a device that can be used on planetary surfaces. Next, an innovative concept for a lifting device is introduced, which includes many of the desirable features. The versatility of the device is discussed, including its application to lander unloading, servicing, inspection, regolith excavation and site preparation. Approximate rules, which can be used to size the device for specific payload mass and reach requirements, are provided. Finally, details of a test-bed implementation of the innovative concept, which will be used to validate the structural design and develop operational procedures, is provided.

  17. Surface Evolution of the Sun's Magnetic Field: A Historical Review of the Flux-Transport Mechanism

    Directory of Open Access Journals (Sweden)

    Sheeley Jr. Neil R.

    2005-10-01

    Full Text Available This paper reviews our attempts to understand the transport of magnetic flux on the Sun from the Babcock and Leighton models to the recent revisions that are being used to simulate the field over many sunspot cycles. In these models, the flux originates in sunspot groups and spreads outward on the surface via supergranular diffusion; the expanding patterns become sheared by differential rotation, and the remnants are carried poleward by meridional flow. The net result of all of the flux eruptions during a sunspot cycle is to replace the initial polar fields with new fields of opposite polarity. A central issue in this process is the role of meridional flow, whose relatively low speed is near the limit of detection with Doppler techniques. A compelling feature of Leighton’s original model was that it reversed the polar fields without the need for meridional flow. Now, we think that meridional flow is central to the reversal and to the dynamo itself.

  18. Geocenter motion due to surface mass transport from GRACE satellite data

    Science.gov (United States)

    Riva, R. E. M.; van der Wal, W.; Lavallée, D. A.; Hashemi Farahani, H.; Ditmar, P.

    2012-04-01

    Measurements of mass redistribution from satellite gravimetry are insensitive to geocenter motions. However, geocenter motions can be constrained by satellite gravity data alone if we partition mass changes between land and oceans, under the assumption that the ocean is passive (i.e., in gravitational equilibrium with the land load and the solid earth). Here, we make use of 8 years (2003-2010) of optimally filtered monthly GRACE-based solutions produced at TU Delft to determine changes in the land load and the corresponding geocenter motion, through an iterative procedure. We pay particular attention to correcting for signal leakage caused by the limited spatial resolution of GRACE. We also investigate how the choice of a model of glacial isostatic adjustment (GIA) affects the estimated geocenter motion trend due to present-day surface mass transport. Finally, we separate the contribution of ice masses from that of land hydrology and show how they have a different sensitivity to the chosen GIA model and observational time-span.

  19. A strategy for representing the effects of convective momentum transport in multiscale models: Evaluation using a new superparameterized version of the Weather Research and Forecast model (SP-WRF)

    Science.gov (United States)

    Tulich, S. N.

    2015-06-01

    This paper describes a general method for the treatment of convective momentum transport (CMT) in large-scale dynamical solvers that use a cyclic, two-dimensional (2-D) cloud-resolving model (CRM) as a "superparameterization" of convective-system-scale processes. The approach is similar in concept to traditional parameterizations of CMT, but with the distinction that both the scalar transport and diagnostic pressure gradient force are calculated using information provided by the 2-D CRM. No assumptions are therefore made concerning the role of convection-induced pressure gradient forces in producing up or down-gradient CMT. The proposed method is evaluated using a new superparameterized version of the Weather Research and Forecast model (SP-WRF) that is described herein for the first time. Results show that the net effect of the formulation is to modestly reduce the overall strength of the large-scale circulation, via "cumulus friction." This statement holds true for idealized simulations of two types of mesoscale convective systems, a squall line, and a tropical cyclone, in addition to real-world global simulations of seasonal (1 June to 31 August) climate. In the case of the latter, inclusion of the formulation is found to improve the depiction of key synoptic modes of tropical wave variability, in addition to some aspects of the simulated time-mean climate. The choice of CRM orientation is also found to importantly affect the simulated time-mean climate, apparently due to changes in the explicit representation of wide-spread shallow convective regions.

  20. Benign Weather Modification

    Science.gov (United States)

    2007-11-02

    operational interest in modifying weather to support combat operations increased, ultimately leading to a multi-service effort called PROJECT POPEYE . The goal...This, coupled with the revelations concerning weather modification use in the Vietnam War (PROJECT POPEYE ), was a double blow to weather modification...AWS-TR-74-247, June 1984. Cobb, James T., Jr., et. al. Project Popeye : Final Report. China Lake, CA: Naval Weapons Center, 1967. Langmuir, Irving

  1. Is Weather Chaotic?

    CERN Document Server

    Raidl, A

    1998-01-01

    The correlation dimension and K2-entropy are estimated from meteorological time- series. The results lead us to claim that seasonal variability of weather is under influence of low dimensional dynamics, whereas changes of weather from day to day are governed by high dimensional system(s). Error-doubling time of this system is less than 3 days. We suggest that the outstanding feature of the weather dynamics is deterministic chaos.

  2. The fate of chromium during tropical weathering

    DEFF Research Database (Denmark)

    Berger, Alfons; Frei, Robert

    2014-01-01

    . The negatively fractionated δ53Cr values measured in the weathering profile relative to the unaltered tonalitic bedrock characterized by a high temperature magmatic inventory Cr isotope signature are consistent with loss of a positively fractionated Cr(VI) pool formed during weathering. The predicted existence......We performed a mineral, geochemical and Cr–Sr–Pb isotope study on a laterite profile developed on ca. 540 Ma old tonalitic bedrock in Madagascar with special emphasis on the behavior of chromium during tropical weathering. The observed strong depletions of Ca, Si, and P, and enrichment of Fe and Al...... of the soil profile relative to stage one altered saprolite. This gain in Cr is accompanied by decreasing δ53Cr values and can be explained by partial immobilization (possibly by adsorption/coprecipitation on/with Fe-oxy-hydroxides) of mobile Cr(III) during upward transport in the weathering profile...

  3. Space Weather Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Space Weather Computational Laboratory is a Unix and PC based modeling and simulation facility devoted to research analysis of naturally occurring electrically...

  4. Space Weather Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Space Weather Analysis archives are model output of ionospheric, thermospheric and magnetospheric particle populations, energies and electrodynamics

  5. Modeling Np and Pu transport with a surface complexation model and spatially variant sorption capacities: Implications for reactive transport modeling and performance assessments of nuclear waste disposal sites

    Science.gov (United States)

    Glynn, P.D.

    2003-01-01

    One-dimensional (1D) geochemical transport modeling is used to demonstrate the effects of speciation and sorption reactions on the ground-water transport of Np and Pu, two redox-sensitive elements. Earlier 1D simulations (Reardon, 1981) considered the kinetically limited dissolution of calcite and its effect on ion-exchange reactions (involving 90Sr, Ca, Na, Mg and K), and documented the spatial variation of a 90Sr partition coefficient under both transient and steady-state chemical conditions. In contrast, the simulations presented here assume local equilibrium for all reactions, and consider sorption on constant potential, rather than constant charge, surfaces. Reardon's (1981) seminal findings on the spatial and temporal variability of partitioning (of 90Sr) are reexamined and found partially caused by his assumption of a kinetically limited reaction. In the present work, sorption is assumed the predominant retardation process controlling Pu and Np transport, and is simulated using a diffuse-double-layer-surface-complexation (DDLSC) model. Transport simulations consider the infiltration of Np- and Pu-contaminated waters into an initially uncontaminated environment, followed by the cleanup of the resultant contamination with uncontaminated water. Simulations are conducted using different spatial distributions of sorption capacities (with the same total potential sorption capacity, but with different variances and spatial correlation structures). Results obtained differ markedly from those that would be obtained in transport simulations using constant Kd, Langmuir or Freundlich sorption models. When possible, simulation results (breakthrough curves) are fitted to a constant K d advection-dispersion transport model and compared. Functional differences often are great enough that they prevent a meaningful fit of the simulation results with a constant K d (or even a Langmuir or Freundlich) model, even in the case of Np, a weakly sorbed radionuclide under the

  6. Changes in Global Silicate Weathering Feedbacks over Phanerozoic Time

    Science.gov (United States)

    West, A. J.

    2015-12-01

    The release of carbon from the solid Earth exerts a first-order control on the evolution of the planetary environment. This basic climate forcing is modulated by a host of chemical reactions at the Earth's surface, the pace of which are in turn regulated by tectonic forces. Together, these various pieces in the puzzle of the global carbon cycle have been identified for decades, but understanding of how they fit together has remained elusive and continues to be much debated. In particular, we now know the climate-dependence of silicate mineral weathering may vary as a function of denudation rate, which is related to tectonic drivers. This variation suggests that the strength of the weathering feedback may have varied in the past, with consequent implications for the past state of global climate. This work will survey and synthesize approaches to representing changes in the weathering feedback, showing that relatively simple parameterizations yield similar results as recently developed reactive transport approaches. This similarity gives confidence in applying the simple parameterizations to reconstructing changes in feedback strength in the geologic past, at least over Phanerozoic timescales, and allows inclusion of this effect explicitly in carbon cycle models.

  7. Mass transfer in fuel cells. [electron microscopy of components, thermal decomposition of Teflon, water transport, and surface tension of KOH solutions

    Science.gov (United States)

    Walker, R. D., Jr.

    1973-01-01

    Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.

  8. 内蒙古半干旱区沙尘天气特征及其与地表特征的关系%Characteristics of Sand-dust Weather and the Relationship between Land Surface Conditions and Sand-dust Weather in Semiarid Region of Inner Mongolia,China

    Institute of Scientific and Technical Information of China (English)

    陈亿; 尚可政; 王式功; 李艳; 熊光洁

    2013-01-01

    In this paper,based on meteorological data from the Zhurihe meteorological station and normalized difference vegetation index (NDVI),leaf area index (LAI),net primary productivity (NPP) in Zhurihe from 2002 to 2010,the characteristics of sand-dust weather and the relationships between land surface conditions and sand-dust weather in zhurihe were analyzed.The threshold wind speed is 9.4 m· s-1 in Zhurihe.The frequency of sand-dust weather and strong wind is fluctuant from 2002 to 2010.Sand-dust weather frequency is positively correlated with strong wind.Wind of more than 18 m·s-1 can easily lead to sand-dust weather.The normalized dust outbreak frequency (NfDo) is defined as the ratio of sand-dust weather frequency to strong wind frequency.NfDo in spring was always low in Zhurihe,when the accumulated precipitation amount from June to August,maximum NDVI,maximum LAI and maximum NPP from June to August during the previous year exceeded their thresholds (100 mm,0.24,0.3 and 0.6 g C· m-2 · d-1,respectively).It suggests that the precipitation amount during the vegetation growing season predominantly controls plant production in summer and the land erodibility in spring of the next year and suppress sand-dust outbreak.%利用2002-2010年朱日和气象站观测资料,结合同期归一化植被指数(NDVI),叶面积指数(LAI),植被净初级生产力(NPP)资料,分析了内蒙古半干旱区朱日和地区2002-2010年的沙尘天气特征.结果表明:朱日和地区临界起沙风速为9.4m·s-1,2002-2010年沙尘天气频率和大于临界起沙风速频率呈波动变化,沙尘天气频率和大于临界起沙风速频率有很好相关性,超过18m·s-1的强风极易导致沙尘天气的发生;定义标准化的沙尘天气频率(NfDo)为沙尘天气频率与大于临界起沙风速频率之比,当夏季降水量大于100mm,夏季最大NDVI、最大LAI和最大NPP分别大于0.24、0.3g·m-2·d-1和0.6g·m-2·d-1(以碳计算)时,次年春季NfDO较低,沙尘

  9. Relating a Jet-Surface Interaction Experiment to a Commercial Supersonic Transport Aircraft Using Numerical Simulations

    Science.gov (United States)

    Dippold, Vance F. III; Friedlander, David

    2017-01-01

    Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for a commercial supersonic transport aircraft concept and experimental hardware models designed to represent the installed propulsion system of the conceptual aircraft in an upcoming test campaign. The purpose of the experiment is to determine the effects of jet-surface interactions from supersonic aircraft on airport community noise. RANS simulations of the commercial supersonic transport aircraft concept were performed to relate the representative experimental hardware to the actual aircraft. RANS screening simulations were performed on the proposed test hardware to verify that it would be free from potential rig noise and to predict the aerodynamic forces on the model hardware to assist with structural design. The simulations showed a large region of separated flow formed in a junction region of one of the experimental configurations. This was dissimilar with simulations of the aircraft and could invalidate the noise measurements. This configuration was modified and a subsequent RANS simulation showed that the size of the flow separation was greatly reduced. The aerodynamic forces found on the experimental models were found to be relatively small when compared to the expected loads from the model’s own weight.Reynolds-Averaged Navier-Stokes (RANS) simulations were completed for two configurations of a three-stream inverted velocity profile (IVP) nozzle and a baseline single-stream round nozzle (mixed-flow equivalent conditions). For the Sideline and Cutback flow conditions, while the IVP nozzles did not reduce the peak turbulent kinetic energy on the lower side of the jet plume, the IVP nozzles did significantly reduce the size of the region of peak turbulent kinetic energy when compared to the jet plume of the baseline nozzle cases. The IVP nozzle at Sideline conditions did suffer a region of separated flow from the inner stream nozzle splitter that did produce an intense, but small, region of

  10. GPS based surface displacements – a proxy for discharge and sediment transport from the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    B. Hasholt

    2014-07-01

    Full Text Available The elastic respond of the Earth's surface to mass changes has been measured with Global Positioning System (GPS. Mass loss as accumulated runoff and sediment transport from a 10 000 km2 segment of the Greenland Ice Sheet (GrIS correlated very well (R2 = 0.83 with GPS measured uplift. Accumulated winter precipitation correlated fairly well with surface depression (R2 = 0.69. The relationships are based on seven years of runoff and sediment transport observations from the Watson River (2007–2013, winter precipitation from Kangerlussuaq Airport and GPS observations at Kellyville. GPS recordings of surface subsidence and uplift from 1996–2013 are used to calculate 18 years time series of annual runoff, sediment and solute transport and winter precipitation. Runoff and related transport of sediment and solutes increase over the period, while winter precipitation (land depression tends to decrease. Based on the entire GPS record (1996–2013, it is shown that until 2005–2006 the mass balance of this segment of the GrIS was rather stable – since then there has been an increasing loss of mass, culminating in 2012.

  11. 14 CFR 23.961 - Fuel system hot weather operation.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system hot weather operation. 23.961 Section 23.961 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Fuel System § 23.961 Fuel system hot weather operation. Each fuel system must be free from vapor...

  12. Designing a Weather Station

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    The collection and analysis of weather data is crucial to the location of alternate energy systems like solar and wind. This article presents a design challenge that gives students a chance to design a weather station to collect data in advance of a large wind turbine installation. Data analysis is a crucial part of any science or engineering…

  13. Clay mineral distribution in surface sediments of the South China Sea and its significance for in sediment sources and transport

    Institute of Scientific and Technical Information of China (English)

    刘建国; 陈木宏; 陈忠; 颜文

    2010-01-01

    Clay minerals of surface sediments in the South China Sea (SCS) are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis (GSTA) model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS (north of 20°N) between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediment...

  14. Transport and deposition of nitrogen oxides and ozone in the atmospheric surface layer

    Science.gov (United States)

    Li, Yongxian

    Tropospheric ozone is an important photochemical air pollutant, which increases respiratory-related diseases, decreases crop yields, and causes other environmental problems. This research has focused on the measurement of soil biogenic emissions of nitric oxide (NO), one of the precursors for ozone formation, from intensively managed soils in the Southeast US, and examined the transport and deposition of NOx (NO + NO2) and ozone in the atmospheric surface layer, and the effects of NO emissions and its chemical reactions on ozone flux and deposition to the earth's surface. Emissions of nitric oxide were measured from an intensively managed agricultural soil, in the lower coastal plain of North Carolina (near Plymouth, NC), using a dynamic chamber technique. Measurements of soil NO emissions in several crop canopies were conducted at four different sites in North Carolina during late spring and summer of 1994-1996. The turbulent fluxes of NO2 and O3 at 5 m and 10 m above the ground were measured using the eddy-correlation technique near Plymouth, NC during late spring of 1995 and summer of 1996, concurrent with measurements of soil NO emissions using the dynamic chamber system. Soil NO emission from within the corn field was high averaging approximately 35 ng N/m2/s during the measurement period of 1995. In another study, vertical measurements of ozone were made on a 610 m tall tower located 15 km Southeast of Raleigh, NC during the summers of 1993-1997, as part of an effort by the State of North Carolina to develop a State Implementation Plan (SIP) for ozone control in the Raleigh Metropolitan Statistical Area. A strong correlation was observed between the nighttime and early morning ozone concentrations in the residual layer (CR) above the NBL and the maximum ground level concentration (C o max) the following afternoon. Based on this correlation, an empirical regression equation (Co max = 27.67*exp(0.016 CR)) was developed for predicting maximum ground level ozone

  15. A non-equilibrium model for soil heating and moisture transport during extreme surface heating

    Directory of Open Access Journals (Sweden)

    W. J. Massman

    2015-03-01

    Full Text Available With increasing use of prescribed fire by land managers and increasing likelihood of wildfires due to climate change comes the need to improve modeling capability of extreme heating of soils during fires. This issue is addressed here by developing a one-dimensional non-equilibrium model of soil evaporation and transport of heat, soil moisture, and water vapor, for use with surface forcing ranging from daily solar cycles to extreme conditions encountered during fires. The model employs a linearized Crank–Nicolson scheme for the conservation equations of energy and mass and its performance is evaluated against dynamic soil temperature and moisture observations obtained during laboratory experiments on soil samples exposed to surface heat fluxes ranging between 10 000 and 50 000 W m−2. The Hertz–Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. The model includes a dynamic residual soil moisture as a function of temperature and soil water potential, which allows the model to capture some of the dynamic aspects of the strongly bound soil moisture that seems to require temperatures well beyond 150 °C to fully evaporate. Furthermore, the model emulates the observed increase in soil moisture ahead of the drying front and the hiatus in the soil temperature rise during the strongly evaporative stage of drying. It also captures the observed rapid evaporation of soil moisture that occurs at relatively low temperatures (50–90 °C. Sensitivity analyses indicate that the model's success results primarily from the use of a temperature and moisture potential dependent condensation coefficient in the evaporative source term. The model's solution for water vapor density (and vapor pressure, which can exceed one standard atmosphere, cannot be experimentally verified, but they are supported by results from (earlier and very different models developed for somewhat different purposes and for different porous

  16. Biomimetic Bacterial Identification Platform Based on Thermal Wave Transport Analysis (TWTA) through Surface-Imprinted Polymers.

    Science.gov (United States)

    Steen Redeker, Erik; Eersels, Kasper; Akkermans, Onno; Royakkers, Jeroen; Dyson, Simba; Nurekeyeva, Kunya; Ferrando, Beniamino; Cornelis, Peter; Peeters, Marloes; Wagner, Patrick; Diliën, Hanne; van Grinsven, Bart; Cleij, Thomas Jan

    2017-05-12

    This paper introduces a novel bacterial identification assay based on thermal wave analysis through surface-imprinted polymers (SIPs). Aluminum chips are coated with SIPs, serving as synthetic cell receptors that have been combined previously with the heat-transfer method (HTM) for the selective detection of bacteria. In this work, the concept of bacterial identification is extended toward the detection of nine different bacterial species. In addition, a novel sensing approach, thermal wave transport analysis (TWTA), is introduced, which analyzes the propagation of a thermal wave through a functional interface. The results presented here demonstrate that bacterial rebinding to the SIP layer resulted in a measurable phase shift in the propagated wave, which is most pronounced at a frequency of 0.03 Hz. In this way, the sensor is able to selectively distinguish between the different bacterial species used in this study. Furthermore, a dose-response curve was constructed to determine a limit of detection of 1 × 10(4) CFU mL(-1), indicating that TWTA is advantageous over HTM in terms of sensitivity and response time. Additionally, the limit of selectivity of the sensor was tested in a mixed bacterial solution, containing the target species in the presence of a 99-fold excess of competitor species. Finally, a first application for the sensor in terms of infection diagnosis is presented, revealing that the platform is able to detect bacteria in clinically relevant concentrations as low as 3 × 10(4) CFU mL(-1) in spiked urine samples.

  17. Weather and road capacity

    DEFF Research Database (Denmark)

    Jensen, Thomas Christian

    2014-01-01

    The paper presents estimations of the effect of bad weather on the observed speed on a Danish highway section; Køge Bugt Motorvejen. The paper concludes that weather, primarily precipitation and snow, has a clear negative effect on speed when the road is not in hypercongestion mode. Furthermore......, the capacity of the highway seems to be reduced in bad weather and there are indications that travel time variability is also increased, at least in free-flow conditions. Heavy precipitation reduces speed and capacity by around 5-8%, whereas snow primarily reduces capacity. Other weather variables......-parametrically against traffic density and in step 2 the residuals from step 1 are regressed linearly against the weather variables. The choice of a non-parametric method is made to avoid constricting ties from a parametric specification and because the focus here is not on the relationship between traffic flow...

  18. Geophysics in the Critical Zone: Constraints on Deep Weathering and Water Storage Potential in the Southern Sierra CZO

    Science.gov (United States)

    Holbrook, W.; Riebe, C. S.; Hayes, J. L.; Reeder, K.; Harry, D. L.; Malazian, A. I.; Dosseto, A.; Hartsough, P. C.; Hopmans, J. W.

    2012-12-01

    Quantifying the depth and degree of subsurface weathering in landscapes is crucial for quantitative understanding of the biogeochemistry of weathering, the mechanics of hillslope sediment transport, and biogeochemical cycling of nutrients and carbon over both short and long timescales. Although the degree of weathering can be readily measured from geochemical and physical properties of regolith and rock, many distributed samples are needed to measure it over broad spatial scales. Moreover, quantifying the thickness of subsurface weathering has remained challenging, in part because the interface between altered and unaltered rock is often buried at difficult to access depths. To overcome these challenges, we combined seismic refraction and resistivity surveys to estimate regolith thickness and generate representative hillslope-scale images of subsurface weathering and water storage at the Southern Sierra Critical Zone Observatory (SSCZO). Inferred seismic velocities and electrical resistivities of the subsurface provide evidence for a weathering zone with thickness ranging from 10 to 35 m (average = 23 m) along one intensively studied transect. This weathering zone consists of roughly equal thicknesses of saprolite (P-velocity < 2 km/s) and moderately weathered bedrock (P-velocity < 4 km/s). We use a rock physics model of seismic velocities, based on Hertz-Mindlin contact theory, to estimate lateral and vertical variations in porosity as a metric of water storage potential along the transect. Inferred porosities are as high as 55% near the surface and decrease to zero at the base of weathered rock. Model-predicted porosities are broadly consistent with values measured from physical properties of saprolite, suggesting that our analysis of the geophysical data provides realistic estimates of subsurface water storage potential. A major advantage of our geophysical approach is that it quickly and non-invasively quantifies porosity over broad vertical and lateral scales

  19. The weathering of municipal solid waste incineration bottom ash evaluated by some weathering indices for natural rock.

    Science.gov (United States)

    Takahashi, Fumitake; Shimaoka, Takayuki

    2012-12-01

    The weathering of municipal solid waste incineration (MSWI) residues consists of complicated phenomena. This makes it difficult to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash, which was relevant interactively to pH neutralization and formation of secondary minerals. In this study, mineralogical weathering indices for natural rock profiles were applied to fresh/landfilled MSWI bottom ash to investigate the relation of these weathering indices to landfill time and leaching concentrations of component elements. Tested mineralogical weathering indices were Weathering Potential Index (WPI), Ruxton ratio (R), Weathering Index of Parker (WIP), Vogt's Residual Index (V), Chemical Index of Alternation (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alternation (PIA), Silica-Titania Index (STI), Weathering Index of Miura (Wm), and Weatherability index of Hodder (Ks). Welch's t-test accepted at 0.2% of significance level that all weathering indices could distinguish fresh and landfilled MSWI bottom ash. However, R and STI showed contrasted results for landfilled bottom ash to theoretical expectation. WPI, WIP, Wm, and Ks had good linearity with reclamation time of landfilled MSWI bottom ash. Therefore, these four indices might be applicable as an indicator to identify fresh/weathered MSWI bottom ash and to estimate weathering time. Although WPI had weak correlation with leachate pH, other weathering indices had no significant correlation. In addition, all weathering indices could not explain leaching concentration of Al, Ca, Cu, and Zn quantitatively. Large difficulty to modify weathering indices correctly suggests that geochemical simulation including surface sorption, complexation with DOM, and other mechanisms seems to be the only way to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Fluvial transport and surface enrichment of arsenic in semi-arid mining regions: examples from the Mojave Desert, California.

    Science.gov (United States)

    Kim, Christopher S; Stack, David H; Rytuba, James J

    2012-07-01

    As a result of extensive gold and silver mining in the Mojave Desert, southern California, mine wastes and tailings containing highly elevated arsenic (As) concentrations remain exposed at a number of former mining sites. Decades of weathering and erosion have contributed to the mobilization of As-enriched tailings, which now contaminate surrounding communities. Fluvial transport plays an intermittent yet important and relatively undocumented role in the migration and dispersal of As-contaminated mine wastes in semi-arid climates. Assessing the contribution of fluvial systems to tailings mobilization is critical in order to assess the distribution and long-term exposure potential of tailings in a mining-impacted environment. Extensive sampling, chemical analysis, and geospatial mapping of dry streambed (wash) sediments, tailings piles, alluvial fans, and rainwater runoff at multiple mine sites have aided the development of a conceptual model to explain the fluvial migration of mine wastes in semi-arid climates. Intense and episodic precipitation events mobilize mine wastes downstream and downslope as a series of discrete pulses, causing dispersion both down and lateral to washes with exponential decay behavior as distance from the source increases. Accordingly a quantitative model of arsenic concentrations in wash sediments, represented as a series of overlapping exponential power-law decay curves, results in the acceptable reproducibility of observed arsenic concentration patterns. Such a model can be transferable to other abandoned mine lands as a predictive tool for monitoring the fate and transport of arsenic and related contaminants in similar settings. Effective remediation of contaminated mine wastes in a semi-arid environment requires addressing concurrent changes in the amounts of potential tailings released through fluvial processes and the transport capacity of a wash.