WorldWideScience

Sample records for surface transportation committee

  1. 78 FR 58383 - Renewal of Rail Energy Transportation Advisory Committee

    Science.gov (United States)

    2013-09-23

    ... TRANSPORTATION Surface Transportation Board Renewal of Rail Energy Transportation Advisory Committee AGENCY: Surface Transportation Board, DOT. ACTION: Notice of intent to renew charter. SUMMARY: In accordance with... the Surface Transportation Board (Board) intends to renew the charter of the Rail...

  2. 76 FR 78329 - Commercial Space Transportation Advisory Committee; Public Teleconference

    Science.gov (United States)

    2011-12-16

    ... TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space... Commercial Space Transportation Advisory Committee (COMSTAC). The teleconference will take place on...

  3. 77 FR 35102 - Commercial Space Transportation Advisory Committee; Public Teleconference

    Science.gov (United States)

    2012-06-12

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Working Group (OWG) of the Commercial Space Transportation Advisory Committee (COMSTAC)....

  4. 78 FR 53496 - Commercial Space Transportation Advisory Committee; Public Teleconference

    Science.gov (United States)

    2013-08-29

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Space Transportation Advisory Committee (COMSTAC). DATES: The teleconference will take place on...

  5. 76 FR 82031 - Commercial Space Transportation Advisory Committee; Public Teleconference

    Science.gov (United States)

    2011-12-29

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... teleconference of the Commercial Space Transportation Advisory Committee (COMSTAC) Risk Management Working...

  6. 78 FR 53497 - Commercial Space Transportation Advisory Committee; Closed Session

    Science.gov (United States)

    2013-08-29

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Closed Session AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory... closed session of the Commercial Space Transportation Advisory Committee (COMSTAC). The special...

  7. 77 FR 71478 - Notice of Rail Energy Transportation Advisory Committee Vacancies

    Science.gov (United States)

    2012-11-30

    ... Surface Transportation Board Notice of Rail Energy Transportation Advisory Committee Vacancies AGENCY... vacancies on the Board's Rail Energy Transportation Advisory Committee for (1) a representative from a state... those vacancies. DATES: Suggestions of candidates for membership on RETAC are due December 27,...

  8. 78 FR 64291 - Notice of Rail Energy Transportation Advisory Committee Vacancy

    Science.gov (United States)

    2013-10-28

    ... Surface Transportation Board Notice of Rail Energy Transportation Advisory Committee Vacancy AGENCY... Energy Transportation Advisory Committee (RETAC) for a representative of an electric utility. The Board... for a candidate for membership on RETAC are due November 27, 2013. ADDRESSES: Suggestions may...

  9. 78 FR 23773 - Chemical Transportation Advisory Committee

    Science.gov (United States)

    2013-04-22

    ... of Hazardous Solid Bulk Residue b. Update on International Maritime Organization as it relates to the... Management; Notice of Federal Advisory Committee Meeting. SUMMARY: The Chemical Transportation Advisory... . (Preferred method to avoid delays in processing.) Fax: 202-493-2252. Mail: Docket Management Facility (M-30...

  10. 77 FR 52108 - Commercial Space Transportation Advisory Committee; Open Meeting

    Science.gov (United States)

    2012-08-28

    ... TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee; Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial...

  11. 78 FR 18416 - Commercial Space Transportation Advisory Committee; Open Meeting

    Science.gov (United States)

    2013-03-26

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  12. 78 FR 53496 - Commercial Space Transportation Advisory Committee; Open Meeting

    Science.gov (United States)

    2013-08-29

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee; Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  13. 76 FR 621 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-01-05

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Space Transportation Advisory Committee (COMSTAC). The teleconference will take place on...

  14. 76 FR 12211 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-03-04

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Commercial Space Transportation Advisory Committee (COMSTAC). The teleconference will take place on...

  15. 76 FR 42160 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-07-18

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Space Transportation Operations Working Group of the Commercial Space Transportation Advisory Committee Teleconference. SUMMARY:...

  16. 77 FR 48585 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2012-08-14

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Working Group (OWG) of the Commercial Space Transportation Advisory Committee (COMSTAC)....

  17. 76 FR 4988 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-01-27

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Space Transportation Advisory Committee (COMSTAC). The teleconference will take place on...

  18. 76 FR 41323 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-07-13

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Space Transportation Advisory Committee (COMSTAC). The teleconference will take place on...

  19. 78 FR 1917 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2013-01-09

    ... TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space... Space Transportation Advisory Committee (COMSTAC). DATES: The teleconference will take place on...

  20. 78 FR 70093 - Commercial Space Transportation Advisory Committee-Closed Session

    Science.gov (United States)

    2013-11-22

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Closed Session AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory... closed session of the Commercial Space Transportation Advisory Committee (COMSTAC). The special...

  1. 77 FR 71474 - Commercial Space Transportation Advisory Committee-Charter Renewal

    Science.gov (United States)

    2012-11-30

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Charter Renewal AGENCY... Renewal of the Commercial Space Transportation Advisory Committee (COMSTAC). SUMMARY: FAA announces the... (FAA) on the critical matters facing the U.S. commercial space transportation industry. This...

  2. 75 FR 6250 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

    Science.gov (United States)

    2010-02-08

    ... ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice of... Systems (ITS) Program Advisory Committee (ITSPAC). The Web conference will be held on February 24, 2010... to the study, development, and implementation of intelligent transportation systems. Through...

  3. 76 FR 4743 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-01-26

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Space Vehicle Debris Threat Management report. Interested members of the public may submit...

  4. 76 FR 31673 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

    Science.gov (United States)

    2011-06-01

    ... ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice of... (FACA) (Pub. L. 72-363; 5 U.S.C. app.), a meeting of the Intelligent Transportation Systems (ITS) Program Advisory Committee (ITS PAC). The meeting will be held on June 17, 2011, from 8 a.m. to 4 p.m....

  5. 76 FR 6841 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

    Science.gov (United States)

    2011-02-08

    ... TRANSPORTATION ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice of... (FACA) (Pub. L. 72-363; 5 U.S.C. app. 2), a meeting of the Intelligent Transportation Systems (ITS... study, development, and implementation of intelligent transportation systems. Through its sponsor,...

  6. 75 FR 13643 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

    Science.gov (United States)

    2010-03-22

    ... ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice of... (FACA) (Pub. L. 72-363; 5 U.S.C. app. 2), a meeting of the Intelligent Transportation Systems (ITS... implementation of intelligent transportation systems. Through its sponsor, the ITS Joint Program Office...

  7. 76 FR 51461 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2011-08-18

    ... TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial...

  8. 76 FR 4412 - Commercial Space Transportation Advisory Committee-Closed Session

    Science.gov (United States)

    2011-01-25

    ... TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Closed Session AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... 102-3.160, notice is hereby given of a special closed session of the Commercial Space...

  9. 75 FR 38866 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2010-07-06

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  10. 76 FR 67018 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-10-28

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  11. 76 FR 15041 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2011-03-18

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  12. 75 FR 71791 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2010-11-24

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  13. 75 FR 52058 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2010-08-24

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee-Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  14. 75 FR 51332 - Commercial Space Transportation Advisory Committee-Public Teleconference

    Science.gov (United States)

    2010-08-19

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation... Act (Pub. L. 92-463, 5 U.S.C. App. 2), notice is hereby given of a teleconference of the...

  15. 75 FR 54002 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2010-09-02

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  16. 77 FR 16891 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2012-03-22

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  17. 76 FR 17474 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2011-03-29

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  18. 75 FR 16901 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2010-04-02

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of the meetings of the Commercial...

  19. 78 FR 69742 - Commercial Space Transportation Advisory Committee-Open Meeting

    Science.gov (United States)

    2013-11-20

    ... Federal Aviation Administration Commercial Space Transportation Advisory Committee--Open Meeting AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory.... 92-463, 5 U.S.C. App. 2), notice is hereby given of a meeting of the Commercial Space...

  20. 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...

  1. 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

  2. Committees

    Science.gov (United States)

    2012-11-01

    Leadership Team of the IAHR Committee for Hydraulic Machinery and Systems Eduard EGUSQUIZA, UPC Barcelona, Spain, Chair François AVELLAN, EPFL-LMH, Switzerland, Past Chair Richard K FISHER, Voith Hydro Inc., USA, Past Chair Fidel ARZOLA, Edelca, Venezuela Michel COUSTON, Alstom Hydro, France Niklas DAHLBÄCKCK, Vatenfall, Sweden Normand DESY, Andritz VA TECH Hydro Ltd., Canada Chisachi KATO, University of Tokyo, Japan Andrei LIPEJ, Turboinstitut, Slovenija Torbjørn NIELSEN, NTNU, Norway Romeo SUSAN-RESIGA, 'Politehnica' University Timisoara, Romania Stefan RIEDELBAUCH, Stuggart University, Germany Albert RUPRECHT, Stuttgart University, Germany Qing-Hua SHI, Dong Fang Electrical Machinery Co., China Geraldo TIAGO, Universidade Federal de Itajubá, Brazil International Advisory Committee Shouqi YUAN (principal) Jiangsu University China QingHua SHI (principal) Dong Fang Electrical Machinery Co. China Fidel ARZOLA EDELCA Venezuela Thomas ASCHENBRENNER Voith Hydro GmbH & Co. KG Germany Anton BERGANT Litostroj Power doo Slovenia B C BHAOYAL Research & Technology Centre India Hermod BREKKE NTNU Norway Stuart COULSON Voith Hydro Inc. USA Paul COOPER Fluid Machinery Research Inc USA V A DEMIANOV Power Machines OJSC Russia Bart van ESCH Technische Universiteit Eindhoven Netherland Arno GEHRER Andritz Hydro Graz Austria Akira GOTO Ebara Corporation Japan Adiel GUINZBURG The Boeing Company USA D-H HELLMANN KSB AG Germany Ashvin HOSANGADI Combustion Research and Flow Technology USA Byung-Sun HWANG Korea Institute of Material Science Korea Toshiaki KANEMOTO Kyushu Institute of Technology Japan Mann-Eung KIM Korean Register of Shipping Korea Jiri KOUTNIK Voith Hydro GmbH & Co. KG Germany Jinkook LEE Eaton Corporation USA Young-Ho LEE Korea Maritime University Korea Woo-Seop LIM Hyosung Goodsprings Inc Korea Jun MATSUI Yokohama National University Japan Kazuyoshi Mitsubishi H I Ltd, Japan MIYAGAWA Christophe NICOLET Power Vision Engineering Srl Switzerland Maryse PAGE Hydro

  3. 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.

  4. 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.

  5. Congressional Testimony: Statement of Wade T. Najjum Before the Subcommittee on Water Resources and Environment Committee on Transportation

    Science.gov (United States)

    Statement of Wade T. Najjum Assistant Inspector General for Program Evaluation Office of Inspector General U.S. EPA Before the Subcommittee on Water Resources and Environment Committee on Transportation and Infrastructure U.S. House of Representatives

  6. 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.

  7. 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...

  8. 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.

  9. 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

  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. 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...

  12. Neural network committees for finger joint angle estimation from surface EMG signals

    Directory of Open Access Journals (Sweden)

    Reddy Narender P

    2009-01-01

    Full Text Available Abstract Background In virtual reality (VR systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG together with the actual joint angle measurements were obtained while the subject was performing flexion-extension rotation of the index finger at three speeds. Several neural networks were trained to predict the joint angle from the parameters extracted from the SEMG signals. The best networks were selected to form six committees. The neural network committees were evaluated using data from new subjects. Results There was hysteresis in the measured SMEG signals during the flexion-extension cycle. However, neural network committees were able to predict the joint angle with reasonable accuracy. RMS errors ranged from 0.085 ± 0.036 for fast speed finger-extension to 0.147 ± 0.026 for slow speed finger extension, and from 0.098 ± 0.023 for the fast speed finger flexion to 0.163 ± 0.054 for slow speed finger flexion. Conclusion Although hysteresis was observed in the measured SEMG signals, the committees of neural networks were able to predict the finger joint angle from SEMG signals.

  13. 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

  14. 77 FR 50463 - Transportation and Related Equipment; Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2012-08-21

    ... distribution of public presentation materials to Committee members, the Committee suggests that presenters forward the public presentation materials prior to the meeting to Ms. Springer via email. The Assistant... Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no later than September 6, 2012. A limited...

  15. 75 FR 20816 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2010-04-21

    ... presentation materials to Committee members, the Committee suggests that presenters forward the public presentation materials prior to the meeting to Ms. Springer via email. The Assistant Secretary for... on a first come, first serve basis. To join the conference, submit inquiries to Ms. Yvette...

  16. 78 FR 11143 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2013-02-15

    ... distribution of public presentation materials to Committee members, the Committee suggests that presenters forward the public presentation materials prior to the meeting to Ms. Springer via email. The Assistant... Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no later than February 28, 2013. A limited...

  17. 76 FR 20949 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2011-04-14

    ... presentation materials to Committee members, the Committee suggests that presenters forward the ] public presentation materials prior to the meeting to Ms. Springer via e-mail. The Assistant Secretary for... Springer at Yspringer@bis.doc.gov no later than April 28, 2011. A limited number of seats will be...

  18. 76 FR 3611 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2011-01-20

    ... public presentation materials to Committee members, the Committee suggests that presenters forward the public presentation materials prior to the meeting to Ms. Springer via e-mail. The Assistant Secretary... Ms. Yvette Springer at Yspringer@bis.doc.gov no later than February 3, 2011. A limited number...

  19. 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.

  20. 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...

  1. 78 FR 15112 - Rulemaking Advisory Committee; Transport Airplane Performance and Handling Characteristics-New Task

    Science.gov (United States)

    2013-03-08

    ... new task assignment for the Aviation Rulemaking Advisory Committee (ARAC). SUMMARY: The FAA assigned.... The output of this task is intended to support FAA planning for subsequent ARAC taskings in...

  2. 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.

  3. 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

  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. 76 FR 64895 - Transportation and Related Equipment Technical Advisory Committee; Notice of Open Meeting

    Science.gov (United States)

    2011-10-19

    ... join the conference, submit inquiries to Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no later... suggests that presenters forward the public presentation materials to Yvette Springer. For more information contact Ms. Springer on (202) 482-2813. Dated: October 13, 2011. Yvette Springer, Committee Liaison...

  6. 78 FR 63161 - Transportation and Related Equipment Technical Advisory Committee; Notice of Open Meeting

    Science.gov (United States)

    2013-10-23

    ... basis. To join the conference, submit inquiries to Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no... meeting to Ms. Springer via email. For more information, call Yvette Springer at (202) 482-2813. Dated: October 18, 2013. Yvette Springer, Committee Liaison Officer. BILLING CODE P ...

  7. 75 FR 51442 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2010-08-20

    ... first come, first serve basis. To join the conference, submit inquiries to Ms. Yvette Springer at... materials prior to the meeting to Ms. Springer via e-mail. The Assistant Secretary for Administration, with... Yvette Springer at (202) 482-2813. Dated: August 16, 2010. Yvette Springer, Committee Liaison Officer...

  8. 77 FR 65857 - Transportation and Related Equipment Technical Advisory Committee; Notice of Open Meeting

    Science.gov (United States)

    2012-10-31

    ... basis. To join the conference, submit inquiries to Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no... meeting to Ms. Springer via email. For more information, call Yvette Springer at (202) 482 2813. Dated: October 25, 2012. Yvette Springer, Committee Liaison Officer. BILLING CODE P ...

  9. 76 FR 52312 - Transportation and Related Equipment; Technical Advisory Committee; Notice of Partially Closed...

    Science.gov (United States)

    2011-08-22

    ... Ms. Yvette Springer at Yvette.Springer@bis.doc.gov no later than September 7, 2011. A limited number... forward the public presentation materials prior to the meeting to Ms. Springer via e-mail. The Assistant... Yvette Springer at (202) 482-2813. Dated: August 15, 2011. Yvette Springer, Committee Liaison...

  10. 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 ...

  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. 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.…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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).

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Activities of the Committee for Surface Protection from Mining Damage in the fourth quarter of 1983. [Poland

    Energy Technology Data Exchange (ETDEWEB)

    Chroszcz, A.

    1984-01-01

    The Committee for Surface Protection from Mining Damage analyzed mining of coal seams in the protective pillar of Bytom and the program of coal mining in the protective pillar of Jastrzebie from 1984 to 1985. The Bobrek coal mine proposed mining a thick coal seam under Bytom (Karb and Miechowice area) by slicing with caving (2 slices, each 2.5 m thick). Due to forecast intensive ground subsidence the proposal was not accepted. The Committee recommended use of mining with hydraulic stowing. The Bobrek mine developed a modified plan. The seam would be mined with hydraulic stowing; only one slice, 2.5 m thick, would be removed to reduce ground subsidence. The Committee also analyzed coal mining under Jastrzebie city by 3 coal mines: Jastrzebie, Moszczenica and Manifest Lipcowy. Mining with caving would be used. The Committee critically evaluated mining the protective coal pillar from 1976 to 1982. It also made recommendations on reducing mining damage caused by mining in the protective pillar of Jastrzebie.

  5. 78 FR 30393 - Preparations for the 43rd Session of the United Nations Sub-Committee of Experts on the Transport...

    Science.gov (United States)

    2013-05-22

    ... Administration Preparations for the 43rd Session of the United Nations Sub- Committee of Experts on the Transport... preparation for United Nations meetings being held in Geneva, Switzerland, this summer. PHMSA is hosting the... portion of the meeting to discuss proposals in preparation for the 25th session of the United Nations...

  6. 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.

  7. 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.

  8. 75 FR 53374 - Notice of Rail Energy Transportation Advisory Committee Meeting

    Science.gov (United States)

    2010-08-31

    ... a white paper on industry Best Practices; a Performance Measures subcommittee update on the trends... significantly affect either the quality of the human environment or the conservation of energy resources... transportation by rail of energy ] resources, particularly, but not necessarily limited to, coal, ethanol, and...

  9. 76 FR 17183 - Aviation Rulemaking Advisory Committee; Transport Airplane and Engine Issues-New Task

    Science.gov (United States)

    2011-03-28

    ... airplane hull loss. The National Transportation Safety Board (NTSB) found ``that the probable cause of this.... John's to Deer Lake, Newfoundland, with 36 passengers and 3 crew on board. During the climb-out from St. John's, the indicated airspeed gradually decreased to the point that the airplane entered...

  10. 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.

  11. 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.

  12. 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).

  13. 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.

  14. 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.

  15. 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...

  16. 78 FR 20685 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2013-04-05

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee (ASAC) Meeting AGENCY... Committee Meeting. SUMMARY: The Aviation Security Advisory Committee (ASAC) will meet in Arlington, VA. This.... L. 92-463). The Aviation Security Advisory Committee (ASAC) provides advice and makes...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Activities of the Committee for Surface Protection against Mining Damage in the second quarter of 1987

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    Reviews problems analyzed by the Committee, which is the highest state body approving development programs of coal mines from the point of view of environmental protection. The following programs are analyzed: longwall mining with caving in the safety pillar of the Szombierki power plant in Bytom, coordination of underground mining of the Marklowice coalfield (20.5 km/sup 2/ large) by the Marcel, Jankowice and 1 Maja coal mines, mining with caving or stowing in the safety pillar of Siemianowice city (coal seam 1.6 m thick at 250-320 m depth), program of underground mining in the safety pillar of Bytom for 1987-2010 with a special emphasis on 1987-1990, mining conditions in the area of the Reta housing estate, research programs on tremors caused by underground coal and copper ore mining in Poland, underground mining in the safety pillar of Katowice for 1987-1995, coordination of underground mining in the areas of Miechowice and Karb town districts of Bytom, program for underground mining in the safety pillar of the Orzel Bialy steelworks and Brzeziny town district by the Andaluzja, Rozbark and Barbara-Chorzow mines.

  4. Neural network committees for finger joint angle estimation from surface EMG signals

    OpenAIRE

    Reddy Narender P; Shrirao Nikhil A; Kosuri Durga R

    2009-01-01

    Abstract Background In virtual reality (VR) systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG) signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG togeth...

  5. 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...

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. American Academy of Pediatrics. Committee on Injury and Poison Prevention. Transporting children with special health care needs.

    Science.gov (United States)

    Bull, M; Agran, P; Laraque, D; Pollack, S H; Smith, G A; Spivak, H R; Tenenbein, M; Tully, S B; Brenner, R A; Bryn, S; Neverman, C; Schieber, R A; Stanwick, R; Tinsworth, D; Tully, W P; Garcia, V; Katcher, M L

    1999-10-01

    Children with special health care needs should have access to proper resources for safe transportation. This statement reviews important considerations for transporting children with special health care needs and provides current guidelines for the protection of children with specific health care needs, including those with a tracheostomy, a spica cast, challenging behaviors, or muscle tone abnormalities as well as those transported in wheelchairs.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. Conference Committees: Conference Committees

    Science.gov (United States)

    2009-09-01

    International Programm Committee (IPC) Harald Ade NCSU Sadao Aoki University Tsukuba David Attwood Lawrence Berkeley National Laboratory/CXRO Christian David Paul Scherrer Institut Peter Fischer Lawrence Berkeley National Laboratory Adam Hitchcock McMaster University Chris Jacobsen SUNY, Stony Brook Denis Joyeux Lab Charles Fabry de l'Institut d'Optique Yasushi Kagoshima University of Hyogo Hiroshi Kihara Kansai Medical University Janos Kirz SUNY Stony Brook Maya Kiskinova ELETTRA Ian McNulty Argonne National Lab/APS Alan Michette Kings College London Graeme Morrison Kings College London Keith Nugent University of Melbourne Zhu Peiping BSRF Institute of High Energy Physics Francois Polack Soleil Christoph Quitmann Paul Scherrer Institut Günther Schmahl University Göttingen Gerd Schneider Bessy Hyun-Joon Shin Pohang Accelerator Lab Jean Susini ESRF Mau-Tsu Tang NSRRC Tony Warwick Lawrence Berkeley Lab/ALS Local Organizing Committee Christoph Quitmann Chair, Scientific Program Charlotte Heer Secretary Christian David Scientific Program Frithjof Nolting Scientific Program Franz Pfeiffer Scientific Program Marco Stampanoni Scientific Program Robert Rudolph Sponsoring, Financials Alfred Waser Industry Exhibition Robert Keller Public Relation Markus Knecht Computing and WWW Annick Cavedon Proceedings and Excursions and Accompanying Persons Program Margrit Eichler Excursions and Accompanying Persons Program Kathy Eikenberry Excursions and Accompanying Persons Program Marlies Locher Excursions and Accompanying Persons Program

  16. American Academy of Pediatrics: Committee on Injury and Poison Prevention. School bus transportation of children with special health care needs.

    Science.gov (United States)

    2001-08-01

    School systems are responsible for ensuring that children with special needs are safely transported on all forms of federally approved transportation provided by the school system, and a plan should be developed to provide the most current and proper support to children with special transportation requirements. This statement provides current guidelines for the protection of child passengers with specific health care needs, including those with a tracheostomy, those requiring use of car seats, or those transported in wheelchairs. Guidelines that apply to general school transportation should be followed, including the training of staff, provision of nurses or aides if needed, establishment of a written emergency evacuation plan, and a comprehensive infection control program. Research provides the basis for recommendations concerning occupant securement for children in wheelchairs and children with other special needs who are transported on a school bus. Pediatricians can help their patients by being aware of guidelines for restraint systems for children with special needs and by remaining informed of new resources. Pediatricians can also play an important role at the state and local level in the development of school bus specifications.

  17. 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

  18. 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.

  19. 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...

  20. 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...

  1. 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.

  2. 77 FR 26641 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2012-05-04

    ... 4, 2012 Part III Department of Homeland Security Transportation Security Administration Aviation... Aviation Security Advisory Committee (ASAC) Meeting AGENCY: Transportation Security Administration, DHS... Security Administration (TSA) will hold a meeting of the Aviation Security Advisory Committee (ASAC) on May...

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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).

  10. 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...

  11. 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.

  12. 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.

  13. 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).

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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".

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. Audit Committees

    OpenAIRE

    2009-01-01

    We have produced this booklet to explain the role of audit committees as they can help to improve how an organisation is governed. In a company, an audit committee is a group of its directors whose main responsibilities are to: advise all directors about the quality of the company’s financial statements; work with the company’s external auditor; and examine the reports of the company’s internal auditor, if it employs one.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. 78 FR 35043 - Aviation Security Advisory Committee Charter Renewal and Request for Applicants

    Science.gov (United States)

    2013-06-11

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee Charter Renewal and... (TSA) announces the renewal of the charter for the Aviation Security Advisory Committee (ASAC). The... the Aviation Security Advisory Committee Charter Renewal section below. Comments, identified by...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 77 FR 41203 - NASA International Space Station Advisory Committee; Meeting

    Science.gov (United States)

    2012-07-12

    ... SPACE ADMINISTRATION NASA International Space Station Advisory Committee; Meeting AGENCY: National... Administration announces an open meeting of the NASA International Space Station (ISS) Advisory Committee. The... aboard the International Space Station, including transportation, and crew rotation; and, to assess...

  11. 77 FR 66082 - NASA International Space Station Advisory Committee; Meeting

    Science.gov (United States)

    2012-11-01

    ... SPACE ADMINISTRATION NASA International Space Station Advisory Committee; Meeting AGENCY: National... Administration announces an open meeting of the NASA International Space Station (ISS) Advisory Committee. The... aboard the International Space Station, including transportation, and crew rotation; and, to assess...

  12. 77 FR 2765 - NASA International Space Station Advisory Committee; Meeting

    Science.gov (United States)

    2012-01-19

    ... SPACE ADMINISTRATION NASA International Space Station Advisory Committee; Meeting AGENCY: National... Administration announces an open meeting of the NASA International Space Station (ISS) Advisory Committee. The... aboard the International Space Station, including transportation, and crew rotation; and, to assess...

  13. 78 FR 16757 - First Meeting: RTCA Tactical Operations Committee (TOC)

    Science.gov (United States)

    2013-03-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Aviation Administration First Meeting: RTCA Tactical Operations Committee (TOC) AGENCY: Federal... Discussion Committee Operations FAA Taskings Discussion FAA Task Groups Discussion Anticipated Issues for...

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 49 CFR 8.9 - Information Security Review Committee.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Information Security Review Committee. 8.9 Section 8.9 Transportation Office of the Secretary of Transportation CLASSIFIED INFORMATION: CLASSIFICATION/DECLASSIFICATION/ACCESS Classification/Declassification of Information § 8.9 Information Security Review Committee. (a) There is hereby established...

  20. Can progress in reducing alcohol-impaired driving fatalities be resumed? Results of a workshop sponsored by the Transportation Research Board, Alcohol, Other Drugs, and Transportation Committee (ANB50).

    Science.gov (United States)

    Fell, James C; Beirness, Douglas J; Voas, Robert B; Smith, Gordon S; Jonah, Brian; Maxwell, Jane Carlisle; Price, Jana; Hedlund, James

    2016-11-16

    Despite successes in the 1980s and early 1990s, progress in reducing impaired driving fatalities in the United States has stagnated in recent years. Since 1997, the percentage of drivers involved in fatal crashes with illegal blood alcohol concentration (BAC) levels has remained at approximately 20 to 22%. Many experts believe that public complacency, competing social and public health issues, and the lack of political fortitude have all contributed to this stagnation. The number of alcohol-related crashes, injuries, and fatalities is still unacceptable, and most are preventable. The public needs to be aware that the problem presented by drinking drivers has not been solved. Political leaders need guidance on which measures will affect the problem, and stakeholders need to be motivated once again to implement effective strategies. The National Academy of Sciences (NAS) Transportation Research Board (TRB), Alcohol, Other Drugs, and Transportation Committee (ANB50) sponsored a workshop held at the NAS facility in Woods Hole, Massachusetts, on August 24-25, 2015, to discuss the lack of progress in reducing impaired driving and to make recommendations for future progress. A total of 26 experts in research and policy related to alcohol-impaired driving participated in the workshop. The workshop began by examining the static situation in the rate of alcohol-impaired driving fatal crashes to determine what factors may be inhibiting further progress. The workshop then discussed 8 effective strategies that have not been fully implemented in the United States. Workshop participants (16 of the 26) rated their top 3 strategies. 3 strategies received the most support: 1. Impose administrative sanctions for drivers with BACs = 0.05 to 0.08 g/dL. 2. Require alcohol ignition interlocks for all alcohol-impaired driving offenders. 3. Increase the frequency of sobriety checkpoints, including enacting legislation to allow them in the 11 states that currently prohibit them. 5 other

  1. Science: The Recombinant DNA Advisory Committee.

    Science.gov (United States)

    Wright, Susan

    1979-01-01

    Reports on the status of the Recombinant DNA Advisory Committee (RAC) and attempts to rationalize Suburban Highway Policy. Effective communication among members of the RAC is a current problem facing the committee. A federal transportation priority spending policy is suggested during these times of money and fuel shortages. (MA)

  2. 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.

  3. Plasma Science Committee (PLSC)

    Science.gov (United States)

    1990-12-01

    The Plasma Science Committee (PLSC) is a standing committee under the auspices of the Board on Physics and Astronomy, Commission on Physical Sciences, Mathematics, and Applications of the National Academy of Sciences - National Research Council. Plasma sciences represent a broad and diverse field. The PLSC has accepted the responsibility of monitoring the continuing development and assessing the general health of the field as whole. Although select advisory bodies have been created to address specific issues that affect plasma science, such as the Fusion Policy Advisory Committee (FPAC), the PLSC provides a focus for the plasma science community that is unique and essential. The membership of the PLSC is drawn from research laboratories in universities, industry, and government. Areas of expertise on the committee include accelerators and beams, space physics, astrophysics, computational physics and applied mathematics, fusion plasmas, fundamental experiments and theory, radiation sources, low temperature plasmas, and plasma-surface interactions. The PLSC is well prepared to respond to requests for studies on specific issues.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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.

  11. 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

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 77 FR 70543 - Pipeline Safety: Meeting of the Gas Pipeline Advisory Committee and the Liquid Pipeline Advisory...

    Science.gov (United States)

    2012-11-26

    ... for natural gas pipelines and for hazardous liquid pipelines. Both committees were established under... TRANSPORTATION Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Meeting of the Gas Pipeline Advisory Committee and the Liquid Pipeline Advisory Committee AGENCY: Pipeline and...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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 ...

  20. 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

  1. Executive committee

    Science.gov (United States)

    Xiao, Guoqing; Cai, Xiaohong; Ding, Dajun; Ma, Xinwen; Zhao, Yongtao

    2014-04-01

    ChairVice Chair Toshiyuki AzumaRoberto Rivarola Atomic, Molecular & Optical Physics LabUniversidad Nacional de Rosario and Advanced Science InstituteInstituto de Fisica Rosario RIKEN, JapanRosario, Argentina SecretaryMembers Dominique VernhetJoachim Burgdörfer, Austria Institut des NanoSciences de Paris Birgit Lohmann, Australia Université Pierre et Marie Curie Hossein Sadeghpour, USA Paris, FranceThomas Stöhlker, Germany Past ChairJim McCann, UK Barry DunningGuoqing Xiao, China Physics & AstronomyXiaohong Cai, China Rice University, HoustonXinwen Ma, China Texas, USAYongtao Zhao, China TreasurerFernando Martin, Spain Henrik CederquistLuis Mendez, Spain Alba Nova University CenterAnatoli Kheifets, Australia Stockholm University Stockholm, Sweden Details of the general committee are available in the PDF

  2. Conference Committees

    Science.gov (United States)

    2015-11-01

    Scientific Committee Silvia Arrese-Igor Irigoyen (CFM, CSIC - UPV/EHU, Donostia), Javier Campo (ICMA-CSIC, Zaragoza), Carlos Frontera (ICMAB-CSIC, Barcelona), Victoria García Sakai (ISIS, Chilton), Cristina Gómez-Polo (UPNa, Pamplona), Miguel Ángel González (ILL, Grenoble), Pedro Gorría (Universidad Oviedo), Jon Gutiérrez Echevarría (EHU/UPV, Bilbao), J. Iñaki Pérez Landazábal (UPNa, Pamplona), Vicente Recarte (UPNa, Pamplona), Jesús Ruíz Hervías (UPM, Madrid), Vicente Sánchez-Alarcos (UPNa, Pamplona), Antonio Urbina (UPC, Cartagena) Organizing Committee J. Iñaki Pérez Landazábal (Co-Chair), Vicente Recarte ( Co-Chair), Cristina Gómez-Polo, Silvia Larumbe Abuin, Vicente Sánchez-Alarcos Editors of the Proceedings J. Iñaki Pérez Landazábal, Vicente Recarte Plenary speakers Charles Simon (Institut Laue-Langevin, Grenoble, France), Miguel Angel Alario Franco (Universidad Complutense, Madrid, Spain), Dieter Richter (Jülich Centre for Neutron Science, Jülich, Germany), James Yeck (European Spallation Source, Lund, Sweden) Invited speakers Manu Barandiarán (BCMaterials & EHU/UPV), Arantxa Arbe (MFC, CSIC- UPV/EHU), José Luis Martínez (Consorcio ESS-Bilbao), Marta Castellote, IETcc-CSIC), Josep Lluis Tamarit (UPC), Diego Alba-Venero (ISIS), Elizabeth Castillo (CIC Energigune), Josu M. Igartua (EHU/UPV), Antonio Dos Santos (UPM), Alex Masalles (Museu Nacional d'Art de Catalunya), José Abad (UPCT), Claudia Mondelli (ILL), Oscar Fabelo (ILL), Aurora Nogales (IEM-CSIC), Jesús Rodríguez (UC), Gerardo

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. The Investment Committee. AGB Effective Committee Series

    Science.gov (United States)

    Yoder, Jay A.

    2011-01-01

    This publication is part of an AGB series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices included in this text support the objectives of board committees:…

  8. 76 FR 72967 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2011-11-28

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee (ASAC) Meeting AGENCY... Meeting. SUMMARY: The Transportation Security Administration (TSA) will hold a meeting of the Aviation... matters affecting civil aviation security. This meeting is open to the public, but participation is...

  9. 78 FR 41413 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2013-07-10

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee (ASAC) Meeting AGENCY... Meeting. SUMMARY: The Transportation Security Administration (TSA) will hold a meeting of the Aviation... and provides advice and recommendations for improving aviation security measures to the Administrator...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 78 FR 65244 - Rail Vehicles Access Advisory Committee

    Science.gov (United States)

    2013-10-31

    ... assistive listening system, communication access real-time translation (CART), and sign language... TRANSPORTATION BARRIERS COMPLIANCE BOARD 36 CFR Part 1192 RIN 3014-AA42 Rail Vehicles Access Advisory Committee AGENCY: Architectural and Transportation Barriers Compliance Board. ACTION: Notice of advisory committee...

  15. 77 FR 53902 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2012-09-04

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee (ASAC) Meeting AGENCY... Meeting. SUMMARY: The Transportation Security Administration (TSA) will hold a meeting of the Aviation... of the International Aviation Sub-committee, placed in the public docket. You may submit comments on...

  16. 77 FR 2342 - Fifth Meeting: RTCA, Next Gen Advisory Committee

    Science.gov (United States)

    2012-01-17

    ... TRANSPORTATION Federal Aviation Administration Fifth Meeting: RTCA, Next Gen Advisory Committee AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA, NextGen... RTCA, NextGen Advisory Committee. DATES: The meeting will be held February 3, 2012, from 9:30...

  17. 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...

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. Primary system fission product release and transport: A state-of-the-art report to the committee on the safety of nuclear installations

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A.L. [Oak Ridge National Lab., TN (United States)

    1994-06-01

    This report presents a summary of the status of research activities associated with fission product behavior (release and transport) under severe accident conditions within the primary systems of water-moderated and water-cooled nuclear reactors. For each of the areas of fission product release and fission product transport, the report summarizes relevant information on important phenomena, major experiments performed, relevant computer models and codes, comparisons of computer code calculations with experimental results, and general conclusions on the overall state of the art. Finally, the report provides an assessment of the overall importance and knowledge of primary system release and transport phenomena and presents major conclusions on the state of the art.

  14. 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

  15. 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

  16. 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.

  17. Report of working committee 4 ''transmission of gases''; Rapport de la commission 4 ''transport des gaz''

    Energy Technology Data Exchange (ETDEWEB)

    Volskij, E.

    2000-07-01

    Report of the WOC 4 Transmission contains the results of works carried out during 1998-2000 by the Committee members and the three study groups. The most important is: - review of actual situation and prospects for the gas pipeline transmission system development; - report of SG-4.1 'Pipeline Ageing and Rehabilitation', including analysis of pipeline steels, welding and insulation, methods of rehabilitation, the program of pipeline reconstruction; - report of SG-4.2 'Emission monitoring' including appraisal of gas losses and methods of lowering of methane and other emissions of the gas units in different countries; - report of SG-4.3 'Pipelines Integrity Management and Safety' including basic information on gas pipeline failure intensity, key elements of the Integrity Management System of the gas transmission, methods of risk evaluation and the effectiveness of the approach. (authors)

  18. 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).

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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...

  6. 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

  7. 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

  8. 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.

  9. 78 FR 51809 - Seventeenth Meeting: RTCA Special Committee 217-Aeronautical Databases Joint With EUROCAE WG-44...

    Science.gov (United States)

    2013-08-21

    ... Federal Aviation Administration Seventeenth Meeting: RTCA Special Committee 217--Aeronautical Databases Joint With EUROCAE WG-44--Aeronautical Databases AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 217--Aeronautical Databases...

  10. 78 FR 66418 - Eighteenth Meeting: RTCA Special Committee 217-Aeronautical Databases Joint With EUROCAE WG-44...

    Science.gov (United States)

    2013-11-05

    ... Federal Aviation Administration Eighteenth Meeting: RTCA Special Committee 217--Aeronautical Databases Joint With EUROCAE WG-44--Aeronautical Databases AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 217--Aeronautical Databases...

  11. 78 FR 25134 - Sixteenth Meeting: RTCA Special Committee 217-Aeronautical Databases Joint With EUROCAE WG-44...

    Science.gov (United States)

    2013-04-29

    ... Federal Aviation Administration Sixteenth Meeting: RTCA Special Committee 217--Aeronautical Databases Joint With EUROCAE WG-44--Aeronautical Databases AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 217--Aeronautical Databases...

  12. 78 FR 8684 - Fifteenth Meeting: RTCA Special Committee 217-Aeronautical Databases Joint with EUROCAE WG-44...

    Science.gov (United States)

    2013-02-06

    ... Federal Aviation Administration Fifteenth Meeting: RTCA Special Committee 217--Aeronautical Databases Joint with EUROCAE WG-44--Aeronautical Databases AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 217--Aeronautical Databases...

  13. 76 FR 69769 - Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling

    Science.gov (United States)

    2011-11-09

    ... indication of citizenship and affiliation) may be faxed or emailed to: Mark Fuhrmann, Environmental Transport... COMMISSION Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling... the Federal Interagency Steering Committee on Multimedia Environmental Modeling (ISCMEM) will...

  14. 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.

  15. 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.

  16. 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

  17. 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...

  18. 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

  19. 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

  20. 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 ...

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. The Audit Committee. AGB Effective Committee Series

    Science.gov (United States)

    Staisloff, Richard L.

    2011-01-01

    This publication is part of an Association of Governing Boards of Universities and Colleges (AGB) series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices…

  11. The Facilities Committee. AGB Effective Committee Series

    Science.gov (United States)

    Kaiser, Harvey H.

    2012-01-01

    This publication is part of an Association of Governing Boards of Universities and Colleges (AGB) series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices…

  12. The Compensation Committee. AGB Effective Committee Series

    Science.gov (United States)

    Hyatt, Thomas K.

    2013-01-01

    This publication is part of an Association of Governing Boards of Universities and Colleges (AGB) series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices…

  13. The Facilities Committee. AGB Effective Committee Series

    Science.gov (United States)

    Kaiser, Harvey H.

    2012-01-01

    This publication is part of an Association of Governing Boards of Universities and Colleges (AGB) series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices…

  14. 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.

  15. 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

  16. 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.

  17. 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...

  18. 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

  19. 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

  20. 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.

  1. Kinesin-5/Eg5 is important for transport of CARTS from the trans-Golgi network to the cell surface

    Science.gov (United States)

    Villeneuve, Julien; van Galen, Josse; Cruz-Garcia, David; Tagaya, Mitsuo

    2013-01-01

    Here we report that the kinesin-5 motor Klp61F, which is known for its role in bipolar spindle formation in mitosis, is required for protein transport from the Golgi complex to the cell surface in Drosophila S2 cells. Disrupting the function of its mammalian orthologue, Eg5, in HeLa cells inhibited secretion of a protein called pancreatic adenocarcinoma up-regulated factor (PAUF) but, surprisingly, not the trafficking of vesicular stomatitis virus G protein (VSV-G) to the cell surface. We have previously reported that PAUF is transported from the trans-Golgi network (TGN) to the cell surface in specific carriers called CARTS that exclude VSV-G. Inhibition of Eg5 function did not affect the biogenesis of CARTS; however, their migration was delayed and they accumulated near the Golgi complex. Altogether, our findings reveal a surprising new role of Eg5 in nonmitotic cells in the facilitation of the transport of specific carriers, CARTS, from the TGN to the cell surface. PMID:23857769

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

    DEFF Research Database (Denmark)

    Barreto, Lucas

    2014-01-01

    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...

  3. Transport of temperature and humidity variance and covariance in the marine surface layer

    DEFF Research Database (Denmark)

    Sempreviva, A.M.; Højstrup, J.

    1998-01-01

    In this paper we address the budget of potential temperature T and moisture mixing ratio q variances as well as the q - T covariance budget. We focus on the vertical transport and study the quantities contained in these terms. Estimates of transport terms are rare and to the best of our knowledge...

  4. Wind-induced contaminant transport in near-surface soils with application to radon entry into buildings

    Energy Technology Data Exchange (ETDEWEB)

    Riley, W J [Univ. of California, Berkeley, CA (United States)

    1996-05-01

    Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind`s interactions with a building`s superstructure and the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon transport.

  5. 75 FR 60163 - The Future of Aviation Advisory Committee (FAAC) Aviation Safety Subcommittee; Notice of Meeting

    Science.gov (United States)

    2010-09-29

    ... Office of the Secretary of Transportation The Future of Aviation Advisory Committee (FAAC) Aviation... of Transportation. ACTION: The Future of Aviation Advisory Committee (FAAC): Aviation Safety... Transportation, announces a meeting of the FAAC Aviation Safety Subcommittee, which will be held October 19,...

  6. 75 FR 57103 - The Future of Aviation Advisory Committee (FAAC) Aviation Safety Subcommittee; Notice of Meeting

    Science.gov (United States)

    2010-09-17

    ... Office of the Secretary of Transportation The Future of Aviation Advisory Committee (FAAC) Aviation... of Transportation. ACTION: The Future of Aviation Advisory Committee (FAAC): Aviation Safety... Transportation, announces a meeting of the FAAC Aviation Safety Subcommittee, which will be held September...

  7. On the Sensitivity of Atmospheric Model Implied Ocean Heat Transport to the Dominant Terms of the Surface Energy Balance

    Energy Technology Data Exchange (ETDEWEB)

    Gleckler, P J

    2004-11-03

    The oceanic meridional heat transport (T{sub o}) implied by an atmospheric General Circulation Model (GCM) can help evaluate a model's readiness for coupling with an ocean GCM. In this study we examine the T{sub o} from benchmark experiments of the Atmospheric Model Intercomparison Project, and evaluate the sensitivity of T{sub o} to the dominant terms of the surface energy balance. The implied global ocean TO in the Southern Hemisphere of many models is equatorward, contrary to most observationally-based estimates. By constructing a hybrid (model corrected by observations) T{sub o}, an earlier study demonstrated that the implied heat transport is critically sensitive to the simulated shortwave cloud radiative effects, which have been argued to be principally responsible for the Southern Hemisphere problem. Systematic evaluation of one model in a later study suggested that the implied T{sub o} could be equally as sensitive to a model's ocean surface latent heat flux. In this study we revisit the problem with more recent simulations, making use of estimates of ocean surface fluxes to construct two additional hybrid calculations. The results of the present study demonstrate that indeed the implied T{sub o} of an atmospheric model is very sensitive to problems in not only the surface net shortwave, but the latent heat flux as well. Many models underestimate the shortwave radiation reaching the surface in the low latitudes, and overestimate the latent heat flux in the same region. The additional hybrid transport calculations introduced here could become useful model diagnostic tests as estimates of implied ocean surface fluxes are improved.

  8. Accurate testing of aspheric surfaces using the transport of intensity equation by properly selecting the defocusing distance.

    Science.gov (United States)

    Soltani, Peyman; Darudi, Ahmad; Nehmetallah, George; Moradi, Ali Reza; Amiri, Javad

    2016-12-10

    In the last decade, the transport of intensity has been increasingly used in microscopy, wavefront sensing, and metrology. In this study, we verify by simulation and experiment the use of the transport of intensity equation (TIE) in the accurate testing of optical aspheric surfaces. Guided by simulation results and assuming that the experimental setup parameters and the conic constants are known, one can estimate an appropriate defocusing distance Δz that leads to an accurate solution of the TIE. In this paper, this method is verified through the construction of a non-nulled experiment for testing the 2D profile of an aspheric surface. The theoretical method and experimental results are compared to validate the results. Finally, to validate the TIE methodology, the phase distribution obtained by TIE is compared with the phase distribution obtained by a Shack-Hartmann sensor.

  9. A biogeochemical transport model to simulate the attenuation of chlorinated hydrocarbon contaminant fluxes across the groundwater-surface water interface

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Binning, Philip John; Albrechtsen, Hans-Jørgen

    2009-01-01

    Chlorinated hydrocarbons originating from point sources are amongst the most prevalent contaminants of ground water and surface water resources. Riparian zones may play an important role in the attenuation of contaminant concentrations when contaminant plumes flow from groundwater to surface water...... because of the occurrence of redox gradients, strongly reductive conditions and high biological activity. In order to meet the expectations of the EU Water Framework Directive, an evaluation of the impact of such plumes on surface water is needed. The aim of this work is to develop a groundwater transport...... number of geochemical processes, allows the simulation of soil geochemical transformations when microbial by-products are released to surface water, and the consideration of non-linear feedbacks on bacterial growth and pollutant transformations. Sensitivity analysis is performed through Monte Carlo...

  10. Effect of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators

    OpenAIRE

    2013-01-01

    In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultra-relativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface tran...

  11. Control of start-up and dynamic braking of conveyors used for downhill transport in surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Rosseger, A.; Borczyk, Z.; Kwater, M. (POLTEGOR Instytut, Wroclaw (Poland))

    1992-04-01

    Presents the structure of a microprocessor-aided control system for conveyors used in surface mines for downhill transport. Control of motor start-up and braking is performed in 8 speed stages. Permissible starting time duration is taken into consideration. The procedure of direct current braking is described. The microprocessor activates emergency braking by disc brakes if direct current braking is not sufficient. The system was implemented on four conveyors and has been used successfully since 1990.

  12. Surface electrocardiogram and action potential in mice lacking urea transporter UT-B.

    Science.gov (United States)

    Meng, Yan; Zhao, Chunyan; Zhang, Xuexin; Zhao, Huashan; Guo, Lirong; Lü, Bin; Zhao, Xuejian; Yang, Baoxue

    2009-05-01

    UT-B is a urea transporter protein expressed in the kidney and in many non-renal tissues including erythrocytes, brain, heart, bladder and the testis. The objective of this study was to determine the phenotype of UT-B deletion in the heart. UT-B expression in the heart was studied in wild-type mice vs UT-B null mice by utilizing RT-PCR and Western blot. A surface electrocardiogram (ECG) recording (lead II) was measured in wild-type mice and UT-B null mice at the ages of 6, 16 and 52 weeks. For the action potential recording, the ventricular myocytes of 16 w mice were isolated and recorded by floating microelectrode method. The sodium current was recorded by the patch clamp technique. RT-PCR and Western blot showed the UT-B expression in the heart of wild-type mice. No UT-B transcript and protein was found in UT-B null mice. The ECG recording showed that the P-R interval was significantly prolonged in UT-B null mice ((43.5 +/- 4.2), (45.5 +/- 6.9) and (43.8 +/- 7.6) ms at ages of 6, 16 and 52 weeks) vs wild-type mice ((38.6 +/- 2.9), (38.7 +/- 5.6) and (38.2 +/- 7.3) ms, PUT-B null mice (52 w old). The amplitude of action potential and V (max) decreased significantly in UT-B null mice ((92.17 +/- 10.56) and (101.89 +/- 9.54) mV/s) vs those in wild-type mice (vs (110.51 +/- 10.38) and (109.53 +/- 10.64) mV/s, PUT-B null mice ((123.83 +/- 11.17) and (195.43 +/- 16.41) ms) vs that in wild-type mice ((108.27 +/- 10.85) and (171.00 +/- 15.53) ms, PUT-B null mice (-8.80 +/- 0.92) nA vs that in wild-type mice ((-5.98 +/- 1.07) nA, PUT-B deletion causes progressive heart block in mice.

  13. A review of rapid transport of pesticides from sloping farmland to surface waters: Processes and mitigation strategies

    Institute of Scientific and Technical Information of China (English)

    Xiangyu Tang; Bo Zhu; Hidetaka Katou

    2012-01-01

    Pesticides applied to sloping farmland may lead to surface water contamination through rapid transport processes as influenced by the complex topography and high spatial variability of soil properties and land use in hilly or mountainous regions.However,the fate of pesticides applied to sloping farmland has not been sufficiently elucidated.This article reviews the current understanding of pesticide transport from sloping farmland to surface water.It examines overland flow and subsurface lateral flow in areas where surface soil is underlain by impervious subsoil or rocks and tile drains.It stresses the importance of quantifying and modeling the contributions of various pathways to rapid pesticide loss at catchment and regional scales.Such models could be used in scenario studies for evaluating the effectiveness of possible mitigation strategies such as constructing vegetated strips,depressions,wetlands and drainage ditches,and implementing good agricultural practices.Field monitoring studies should also be conducted to calibrate and validate the transport models as well as biophysical-economic models,to optimize mitigation measures in areas dominated by sloping farmland.

  14. 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.

  15. In Situ Determination of the Transport Properties of Near-Surface Concrete Using AC Impedance Spectroscopy Techniques

    Directory of Open Access Journals (Sweden)

    Lipeng Wu

    2016-01-01

    Full Text Available The durability of existing concrete structures has increasingly attracted widespread attention in recent years. The phenomenon of performance degradation is often associated with the intrusion of hazardous ions from outside. As the first barrier to external substances intrusion, the near-surface concrete plays an important role in durability. So the performance of in-service concrete structures often depends on the transport properties of the near-surface concrete. Accordingly, information on service conditions and life prediction can be obtained by testing these transport properties. In this paper, an in situ method for chloride ion diffusion coefficient determination is proposed based on the relationship between the alternating current impedance spectroscopy parameters and the chloride ion diffusion coefficient. By a rational design, the new method can synthetically reflect the transport properties of near-surface concrete and is not affected by the presence of the reinforcing bar. In addition, the experimental results show that the method is in good agreement with “PERMIT” migration test which has been widely used. The proposed method is less time consuming and nondestructive and has good reproducibility.

  16. Redistribution of monocarboxylate transporter 2 on the surface of astrocytes in the human epileptogenic hippocampus

    DEFF Research Database (Denmark)

    Lauritzen, Fredrik; Heuser, Kjell; de Lanerolle, Nihal C

    2012-01-01

    Emerging evidence points to monocarboxylates as key players in the pathophysiology of temporal lobe epilepsy (TLE) with hippocampal sclerosis (mesial temporal lobe epilepsy, MTLE). Monocarboxylate transporters (MCTs) 1 and 2, which are abundantly present on brain endothelial cells and perivascular...

  17. Transport of ultracold neutrons through a mirror system with surface roughness as a velocity filter

    CERN Document Server

    Chizhova, L A; Jenke, T; Cronenberg, G; Geltenbort, P; Abele, H; Burgdörfer, J

    2012-01-01

    We perform classical Monte Carlo simulations of ultracold neutron transport through an absorbing-reflecting mirror system in the Earth's gravitational field. We show that the underlying mixed phase space of regular skipping motion and random motion due to disorder scattering can be exploited to realize a velocity filter for ultracold neutrons. The range of velocities selected is controlled by geometric parameters of the wave guide. Possible applications include investigations of transport and scattering dynamics in confined systems.

  18. A Two-Phase Cooling Loop for Fission Surface Power Waste Heat Transport Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Current lunar-based Fission Surface Power (FSP) Systems that will support sustained surface outposts consist of a nuclear reactor with power converters, whose waste...

  19. 78 FR 65317 - National Committee on Vital and Health Statistics: Meeting Standards Subcommittee

    Science.gov (United States)

    2013-10-31

    ... coding, document-type standards, message content, structure and format standards, transport, vocabulary... the Committee on health information standardization and community health data initiatives. Contact...

  20. Effects of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators

    Science.gov (United States)

    Skinner, B.; Chen, T.; Shklovskii, B. I.

    2013-09-01

    In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultrarelativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review, we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface transport in TIs. We present self-consistent theories for Coulomb screening both in the bulk and at the surface, discuss the magnitude of the disorder potential in each case, and present results for the conductivity. In the bulk, where the band gap leads to thermally activated transport, we show how disorder leads to a smaller-than-expected activation energy that gives way to variable-range hopping at low temperatures. We confirm this enhanced conductivity with numerical simulations that also allow us to explore different degrees of impurity compensation. For the surface, where the TI has gapless Dirac modes, we present a theory of disorder and screening of deep impurities, and we calculate the corresponding zero-temperature conductivity. We also comment on the growth of the disorder potential in passing from the surface of the TI into the bulk. Finally, we discuss how the presence of a gap at the Dirac point, introduced by some source of time-reversal symmetry breaking, affects the disorder potential at the surface and the mid-gap density of states.

  1. 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)

    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. Contaminant transport in the integrated surface and subsurface domains is simulated using advection-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 agricultural watersheds with shallow streams.

  2. 78 FR 40264 - First Meeting: RTCA Tactical Operations Committee (TOC)

    Science.gov (United States)

    2013-07-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Aviation Administration First Meeting: RTCA Tactical Operations Committee (TOC) AGENCY: Federal... approval: Terms of Reference--Structure, Scope, Leadership Anticipated Issues for TOC consideration...

  3. 75 FR 36698 - Committee Management Renewals

    Science.gov (United States)

    2010-06-28

    ... Communications and Cyber Systems, 1196 Proposal Review Panel for Engineering Education and Centers, 173 Proposal... Science and Engineering, 1173 Advisory Committee for Computer and Information Science and Engineering... Panel for Chemical, Bioengineering, Environmental, and Transport Systems, 1189 Proposal Review Panel for...

  4. Transport signatures of surface potentials on three-dimensional topological insulators

    Science.gov (United States)

    Roy, Sthitadhi; Das, Sourin

    2016-02-01

    The spin-momentum-locked nature of the robust surface states of three-dimensional topological insulators (3D TIs) makes them promising candidates for spintronics applications. Surface potentials which respect time-reversal symmetry can exist at the surface between a 3D TI and the trivial vacuum. These potentials can distort the spin texture of the surface states while retaining their gapless nature. In this work, the effect of all such surface potentials on the spin textures is studied. Since a tunnel magnetoresistance signal carries the information of the spin texture, it is proposed that spin-polarized tunneling of electrons to a 3D TI surface can be used to uniquely identify the surface potentials and quantitatively characterize them.

  5. From Soil to Surface Water: a Meta-Analysis of Catchment-Scale Organic Matter Production and Transport

    Science.gov (United States)

    Gabor, R. S.; Brooks, P. D.; Perdrial, J. N.

    2015-12-01

    Organic matter plays a fundamental role in the ecology and biogeochemistry of many ecosystems, from soils to headwater streams to oceans. In most catchments, the terrestrial environment is the dominant source of organic matter for the aquatic system, and thus DOM represents a fundamental linkage between soil and surface water. With trends of increasing DOC concentrations observed in many areas of the world, there is growing interest in identifying which factors drive DOM concentration and chemistry. Studies of systems ranging from tropical rainforests to boreal landscapes have identified many catchment characteristics that co-vary with DOM concentration and chemistry. These include climate elements such as solar radiation and precipitation patterns, chemical measurements such as sulfate or chloride concentration, and land use impacts such as percent agriculture. The question of which catchment characteristics actually control DOM can be broken down into two parts: which factors control the production of mobile DOM and what drives DOM transport from the terrestrial to the aquatic system. Here we review studies covering a range of ecosystems, scales, and measurement techniques, to categorize the major state factors that drive catchment controls of aquatic organic matter. Specifically, we identify three major transport vectors that vary both in their timing of DOM transport to surface water and the propensity for DOM originating from terrestrial source areas to be modified during transport. We use this three vector conceptual model of transport to group catchments and identify reproducible signatures of DOM export with varying levels of disturbance. By developing a generalized conceptual model of catchment-scale controls on aquatic organic matter, we can predict how dissolved organic matter will respond to environmental change. This knowledge can then help guide best management practices.

  6. T tubules and surface membranes provide equally effective pathways of carbonic anhydrase-facilitated lactic acid transport in skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Janine Hallerdei

    Full Text Available We have studied lactic acid transport in the fast mouse extensor digitorum longus muscles (EDL by intracellular and cell surface pH microelectrodes. The role of membrane-bound carbonic anhydrases (CA of EDL in lactic acid transport was investigated by measuring lactate flux in muscles from wildtype, CAIV-, CAIX- and CAXIV-single ko, CAIV-CAXIV double ko and CAIV-CAIX-CAXIV-triple ko mice. This was complemented by immunocytochemical studies of the subcellular localization of CAIV, CAIX and CAXIV in mouse EDL. We find that CAXIV and CAIX single ko EDL exhibit markedly but not maximally reduced lactate fluxes, whereas triple ko and double ko EDL show maximal or near-maximal inhibition of CA-dependent lactate flux. Interpretation of the flux measurements in the light of the immunocytochemical results leads to the following conclusions. CAXIV, which is homogeneously distributed across the surface membrane of EDL fibers, facilitates lactic acid transport across this membrane. CAIX, which is associated only with T tubular membranes, facilitates lactic acid transport across the T tubule membrane. The removal of lactic acid from the lumen of T tubuli towards the interstitial space involves a CO2-HCO3- diffusional shuttle that is maintained cooperatively by CAIX within the T tubule and, besides CAXIV, by the CAIV, which is strategically located at the opening of the T tubules. The data suggest that about half the CA-dependent muscular lactate flux occurs across the surface membrane, while the other half occurs across the membranes of the T tubuli.

  7. Spinel-structured surface layers for facile Li ion transport and improved chemical stability of lithium manganese oxide spinel

    Science.gov (United States)

    Lee, Hae Ri; Seo, Hyo Ree; Lee, Boeun; Cho, Byung Won; Lee, Kwan-Young; Oh, Si Hyoung

    2017-01-01

    Li-ion conducting spinel-structured oxide layer with a manganese oxidation state close to being tetravalent was prepared on aluminum-doped lithium manganese oxide spinel for improving the electrochemical performances at the elevated temperatures. This nanoscale surface layer provides a good ionic conduction path for lithium ion transport to the core and also serves as an excellent chemical barrier for protecting the high-capacity core material from manganese dissolution into the electrolyte. In this work, a simple wet process was employed to prepare thin LiAlMnO4 and LiMg0.5Mn1.5O4 layers on the surface of LiAl0.1Mn1.9O4. X-ray absorption studies revealed an oxidation state close to tetravalent manganese on the surface layer of coated materials. Materials with these surface coating layers exhibited excellent capacity retentions superior to the bare material, without undermining the lithium ion transport characteristics and the high rate performances.

  8. Transport properties of iron-porphyrin molecule sandwiched between Au surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Hisashi [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); CMSC, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)], E-mail: KONDO.Hisashi@nims.go.jp; Kino, Hiori; Nara, Jun [CMSC, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Ohno, Takahisa [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); CMSC, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); MANA, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2008-09-30

    The transport properties of an iron-porphyrin molecule sandwiched between Au(1 1 1) electrodes are investigated using the non-equilibrium Green's function method based on the density functional theory, and in particular, the dependence on a terminal-atom position is studied. We consider four models for terminal-atom positions. It is found that the transport properties of the junction system are very sensitive to a terminal-atom position. We also find that the contribution of the d-orbitals of the Fe atom to the transport properties around the Fermi energy strongly changes, depending on a terminal-atom position. From these results, we propose a suitable terminal-atom position for the molecular sensor discussed in the other paper.

  9. Committee Reports, May 2008

    Science.gov (United States)

    2008-08-01

    The Division's Executive Committee conducted several items of business at the New Orleans meeting. Elsewhere in this issue [see p 1032] is a listing of the candidates for Division offices for Fall 2008 election, approved by the Committee and later affirmed at the Division business meeting. Among items of specific interest to Division members is a plan to have the Journal of Chemical Education send an announcement to members when each issues goes online, and the Committee approved this use of the Division email list. It also approved plans presented by Amina El-Ashmawy and the BCCE committee to proceed with a bid from Pennsylvania State University for the 2012 BCCE.

  10. Consensus, contracts, and committees.

    Science.gov (United States)

    Moreno, J D

    1991-08-01

    Following a brief account of the puzzle that ethics committees present for the Western Philosophical tradition, I will examine the possibility that social contract theory can contribute to a philosophical account of these committees. Passing through classical as well as contemporary theories, particularly Rawls' recent constructivist approach, I will argue that social contract theory places severe constraints on the authority that may legitimately be granted to ethics committees. This, I conclude, speaks more about the suitability of the theory to this level of analysis than about the ethics committee phenomenon itself.

  11. Pseudospin-valve effect on transport in junctions of three-dimensional topological insulator surfaces

    Science.gov (United States)

    Roy, Sthitadhi; Roychowdhury, Krishanu; Das, Sourin

    2016-07-01

    We show that the surface states of pristine 3D topological insulators (TIs) are analogs of ferromagnetic half metals due to complete polarization of an emergent momentum independent pseudospin (SU(2)) degree of freedom on the surface. To put this claim on firm footing, we present results for TI surfaces perpendicular to the crystal growth axis, which clearly show that the tunneling conductance between two such TI surfaces of the same TI material is dominated by this half metallic behavior leading to physics reminiscent of a spin-valve. Further using the generalized tunnel magnetoresistance derived in this work we also study the tunneling current between arbitrary TI surfaces. We also perform a comprehensive study of the effect of all possible surface potentials allowed by time reversal symmetry on this spin-valve effect and show that it is robust against most of such potentials.

  12. Surface electrocardiogram and action potential in mice lacking urea transporter UT-B

    Institute of Scientific and Technical Information of China (English)

    MENG Yan; ZHAO ChunYan; ZHANG XueXin; ZHAO HuaShan; GUO LiRong; Lü Bin; ZHAO XueJian; YANG BaoXue

    2009-01-01

    UT-B is a urea transporter protein expressed in the kidney and in many non-renal tissues including erythrocytes, brain, heart, bladder and the testis. The objective of this study was to determine the phenotype of UT-B deletion in the heart. UT-B expression in the heart was studied in wild-type mice vs UT-B null mice by utilizing RT-PCR and Western blot. A surface electrocardiogram (ECG) recording (lead Ⅱ) was measured in wild-type mice and UT-B null mice at the ages of 6, 16 and 52 weeks. For the action potential recording, the ventricular myocytes of 16 w mice were isolated and recorded by float-ing microelectrode method. The sodium current was recorded by the patch clamp technique. RT-PCR and Western blot showed the UT-B expression in the heart of wild-type mice. No UT-B transcript and protein was found in UT-B null mice. The ECG recording showed that the P-R interval was significantly prolonged in UT-B null mice ((43.5±4.2), (45.5±6.9) and (43.8±7.6) ms at ages of 6, 16 and 52 weeks) vs wild-type mice ((38.6±2.9), (38.7±5.6) and (38.2±7.3) ms, P<0.05). The atrial ventricular heart block type Ⅱ and Ⅲ only appeared in the aging UT-B null mice (52 w old). The amplitude of action potential and Vmax decreased significantly in UT-B null mice ((92.17±10.56) and (101.89±9.54) mV/s) vs those in wild-type mice (vs (110.51±10.38) and (109.53±10.64) mV/s, P<0.05). The action potential duration at 50% and 90% (APD50 and APD90) was significantly prolonged in UT-B null mice ((123.83±11.17) and (195.43±16.41) ms) vs that in wild-type mice ((108.27±10.85) and (171.00±15.53) ms, P<0.05). The maximal sodium current decreased significantly in UT-B null mice (-8.80±0.92) nA vs that in wild-type mice ((-5.98±1.07) nA, P<0.05). These results provide the first evidence that UT-B deletion causes progressive heart block in mice.

  13. Surface electrocardiogram and action potential in mice lacking urea transporter UT-B

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    UT-B is a urea transporter protein expressed in the kidney and in many non-renal tissues including erythrocytes, brain, heart, bladder and the testis. The objective of this study was to determine the phenotype of UT-B deletion in the heart. UT-B expression in the heart was studied in wild-type mice vs UT-B null mice by utilizing RT-PCR and Western blot. A surface electrocardiogram (ECG) recording (lead II) was measured in wild-type mice and UT-B null mice at the ages of 6, 16 and 52 weeks. For the action potential recording, the ventricular myocytes of 16 w mice were isolated and recorded by floating microelectrode method. The sodium current was recorded by the patch clamp technique. RT-PCR and Western blot showed the UT-B expression in the heart of wild-type mice. No UT-B transcript and protein was found in UT-B null mice. The ECG recording showed that the P-R interval was significantly prolonged in UT-B null mice ((43.5 ± 4.2), (45.5 ± 6.9) and (43.8 ± 7.6) ms at ages of 6, 16 and 52 weeks) vs wild-type mice ((38.6 ± 2.9), (38.7 ± 5.6) and (38.2 ± 7.3) ms, P<0.05). The atrial ventricular heart block type II and III only appeared in the aging UT-B null mice (52 w old). The amplitude of action potential and Vmax decreased significantly in UT-B null mice ((92.17 ± 10.56) and (101.89 ± 9.54) mV/s) vs those in wild-type mice (vs (110.51 ± 10.38) and (109.53 ± 10.64) mV/s, P<0.05). The action potential duration at 50% and 90% (APD50 and APD90) was significantly prolonged in UT-B null mice ((123.83 ± 11.17) and (195.43 ± 16.41) ms) vs that in wild-type mice ((108.27 ± 10.85) and (171.00 ± 15.53) ms, P<0.05). The maximal sodium current decreased significantly in UT-B null mice (-8.80 ± 0.92) nA vs that in wild-type mice ((-5.98 ± 1.07) nA, P<0.05). These results provide the first evidence that UT-B deletion causes progressive heart block in mice.

  14. Distributions of clay minerals in surface sediments of the middle Bay of Bengal: Source and transport pattern

    Science.gov (United States)

    Li, Jingrui; Liu, Shengfa; Shi, Xuefa; Feng, Xiuli; Fang, Xisheng; Cao, Peng; Sun, Xingquan; Wenxing, Ye; Khokiattiwong, Somkiat; Kornkanitnan, Narumol

    2017-08-01

    The clay mineral contents in 110 surface sediment samples collected from the middle of the Bay of Bengal were analyzed by X-ray diffraction (XRD) to investigate the provenance and transport patterns. The illite content was highest, followed by chlorite, kaolinite and then smectite, with average weight percent distributions of 52%, 22%, 14% and 12%, respectively. Illite and chlorite had similar distribution pattern, with higher contents in the northern and central areas and lower contents in the southern area, whereas smectite showed the opposite distribution pattern. Kaolinite show no obvious higher or lower areas and the southern ;belt; was one of the highest content areas. Based on the spatial distribution characteristics and cluster analysis results, the study area can be classified into two provinces. Province I covers the southwestern area and contains high concentrations of illite and smectite sediments. Province II covers most sites and is also characterized by high concentrations of illite, but the weight percent of smectite is only half of that of province I. According to a quantitative estimate using end-member clay minerals contents, the relative contributions from the Himalayan source and the Indian source are 63% and 37% on average, respectively. Integrative analysis indicates that the hydrodynamic environment in the study area, especially the turbidity and surface monsoonal circulation, plays an important role in the spatial distribution and dispersal of the clay fraction in the sediments. The sediments in province I are mainly from the Indian source transported by the East Indian Coastal Current (EICC) and the surface monsoon circulation with minor contributions from the Himalayan source while the sediments in province II are mainly from the Himalayan source transported by turbidity and surface monsoonal circulation with little contribution from Indian river materials.

  15. Decadal Arctic surface atmosphere/ocean heat budgets and mass transport estimates from several atmospheric and oceanic reanalyses

    Science.gov (United States)

    Chepurin, gennaday; Carton, James

    2017-04-01

    The Arctic is undergoing dramatic changes associated with the loss of seasonal and permanent ice pack. By exposing the surface ocean to the atmosphere these changes dramatically increase surface exchange processes. In contrast, increases in freshwater and heat input decreases turbulent exchanges within the ocean. In this study we present results from an examination of changing ocean heat flux, storage, and transport during the 36 year period 1980-2015. To identify changes in the surface atmosphere we examine three atmospheric reanalyses: MERRA2, ERA-I, and JRA55. Significant differences in fluxes from these reanalyses arise due to the representation of clouds and water vapor. These differences provide an indication of the uncertainties in the historical record. Next we turn to the Simple Ocean Data Assimilation version 3 (SODA3) global ocean/sea ice reanalysis system to allow us to infer the full ocean circulation from the limited set of historical record of ocean observations. SODA3 has 10 km horizontal resolution in the Arctic and assimilates the full suite of historical marine temperature and salinity observations. To account for the uncertainties in atmospheric forcing, we repeat our analysis with each of the three atmospheric reanalyses. In the first part of the talk we review the climatological seasonal surface fluxes resulting from our reanalysis system, modified for consistency with the ocean observations, and the limits of what we can learn from the historical record. Next we compare the seasonal hydrography, heat, and mass transports with direct estimates from moorings. Finally we examine the impact on the Arctic climate of the changes in sea ice cover and variability and trends of ocean/sea ice heat storage and transport and their contributions to changes in the seasonal stratification of the Arctic Ocean.

  16. Lagrangian study of surface transport in the Kuroshio Extension area based on simulation of propagation of Fukushima-derived radionuclides

    CERN Document Server

    Prants, S V; Uleysky, M Yu

    2013-01-01

    Lagrangian approach is applied to study near-surface large-scale transport in the Kuroshio Extension area using a simulation with synthetic particles advected by AVISO altimetric velocity field. A material line technique is applied to find the origin of water masses in cold-core cyclonic rings pinched off from the jet in summer 2011. Tracking and Lagrangian maps provide the evidence of cross-jet transport. Fukushima derived caesium isotopes are used as Lagrangian tracers to study transport and mixing in the area a few months after the March of 2011 tsunami that caused a heavy damage of the Fukushima nuclear power plant (FNPP). Tracking maps are computed to trace the origin of water parcels with measured levels of Cs-134 and Cs-137 concentrations collected in two R/V cruises in June and July 2011 in the large area of the Northwest Pacific. It is shown that Lagrangian simulation is useful to finding the surface areas that are potentially dangerous due to the risk of radioactive contamination. The results of sim...

  17. Transport Properties and Surface Morphology Correlated Studies on Graphene Formed by Si Desorption of 6H-SiC

    Science.gov (United States)

    Roach, William; Beringer, Douglas; Skuza, Jonathan; Clavero, Cesar; Lukaszew, Rosa Alejandra

    2009-11-01

    Interest in graphene, a single layer of carbon atoms arranged in a hexagonal lattice, has increased in recent years due to exciting characteristics such as its predicted high mobility [1]. However, developing a method to produce graphene that is easily integrated into existing fabrication processes has proved difficult thus far. One promising method is high temperature annealing of 6H-SiC such that Si desorption occurs [2], although this method leads to graphene that exhibits lower mobility than predicted [3]. Thus, we have investigated the relationship between different growth conditions (i.e. annealing time and temperature), the resulting surface morphology and the transport properties of graphene films produced using this method. Raman spectroscopy, atomic force microscopy, and Van der Pauw Hall mobility measurements have been used to correlate the surface morphology to transport properties of graphene formed on SiC. Understanding the effect of growth conditions on the resulting transport properties will help optimize the fabrication of graphene for use in the next generation of electronic devices and other applications. [1] Novoselov et al., Science 306, 666 (2004). [2] C. Berger et al., J. Phys. Chem. B 108, 19912 (2004). [3] G. Gu et al., Appl. Phys. Lett. 90, 253507 (2007).

  18. Transonic unsteady airloads on an energy efficient transport wing with oscillating control surfaces

    Science.gov (United States)

    Sandford, M. C.; Ricketts, R. H.; Cazier, F. W., Jr.; Cunningham, H. J.

    1980-01-01

    An aspect ratio 10.8 supercritical wing with oscillating control surfaces is described. The wing is instrumental with 252 static orifices and 164 in situ dynamic pressure transducers for studying the effects of control surface deflection on steady and unsteady pressures at transonic speeds. Results from initial wind tunnel tests conducted in the Langley Transonic Dynamics Tunnel are discussed. Unsteady pressure results are presented for two trailing edge control surfaces oscillating separately at the design Mach number of 0.78. Some experimental results are compared with analytical results obtained by using linear lifting surface theory.

  19. Molecular dynamics study on mechanism of preformed particle gel transporting through nanopores: Surface chemistry and heterogeneity

    Science.gov (United States)

    Cui, Peng; Zhang, Heng; Ma, Ying; Hao, Qingquan; Liu, Gang; Sun, Jichao; Yuan, Shiling

    2017-10-01

    The translocation behavior of preformed particle gel (PPG) in porous media is crucial for its application in enhanced oil recovery. By means of non-equilibrium molecular dynamics simulation, the translocation mechanism of PPG confined in different silica nanopores were investigated. The influence of surface chemistry and chemical heterogeneity of silica nanopore on the translocation process was revealed. As the degree of surface hydroxylation increases and the heterogeneity decreases, the pulling force needed to drive PPG decreases. We infer that the nanopore's surface (i.e. surface chemistry and heterogeneity) affects the translocation of PPG indirectly by forming different hydration layers.

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

    Science.gov (United States)

    Chen, Bin; Xiang-De, XU

    2017-02-01

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

  1. 77 FR 57638 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2012-09-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... new measures; Formal safety assessment; Piracy and armed robbery against ships; Implementation...

  2. 75 FR 64390 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2010-10-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... --Formal safety assessment --Piracy and armed robbery against ships --General cargo ship...

  3. 76 FR 19176 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2011-04-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct two... safety --Piracy and armed robbery against ships --Implementation of instruments and related...

  4. 78 FR 29201 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2013-05-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... new measures Formal safety assessment Piracy and armed robbery against ships Implementation...

  5. Stability and transport of graphene oxide nanoparticles in groundwater and surface water

    Science.gov (United States)

    A transport study investigating the effects of natural organic matter (NOM) in the presence of monovalent (KCl) and divalent (CaCl2) salts was performed in a packed bed column. The electrophoretic mobility (EPM) and effective diameter of the graphene oxide nanoparticles (GONPs) were measured as a fu...

  6. Solute Transport of Negatively Charged Contrast Agents Across Articular Surface of Injured Cartilage.

    Science.gov (United States)

    Kokkonen, H T; Chin, H C; Töyräs, J; Jurvelin, J S; Quinn, T M

    2017-04-01

    Solute transport through the extracellular matrix (ECM) is crucial to chondrocyte metabolism. Cartilage injury affects solute transport in cartilage due to alterations in ECM structure and solute-matrix interactions. Therefore, cartilage injury may be detected by using contrast agent-based clinical imaging. In the present study, effects of mechanical injury on transport of negatively charged contrast agents in cartilage were characterized. Using cartilage plugs injured by mechanical compression protocol, effective partition coefficients and diffusion fluxes of iodine- and gadolinium-based contrast agents were measured using high resolution microCT imaging. For all contrast agents studied, effective diffusion fluxes increased significantly, particularly at early times during the diffusion process (38 and 33% increase after 4 min, P integrity in cartilage superficial zone. This study suggests that alterations in contrast agent diffusion flux, a non-equilibrium transport parameter, provides a more sensitive indicator for assessment of cartilage matrix integrity than partition coefficient and the equilibrium distribution of solute. These findings may help in developing clinical methods of contrast agent-based imaging to detect cartilage injury.

  7. 77 FR 10599 - Surface Transportation Project Delivery Pilot Program; Caltrans Audit Report

    Science.gov (United States)

    2012-02-22

    ...) Interviews with staff indicated a large staff turnover in certain Districts. The loss of experienced staff... agency staff at the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service (FWS), the National... Transportation Systems Center; U.S. FWS. During the onsite audit, the audit team interviewed more than 60 staff...

  8. Single-electron transport driven by surface acoustic waves: Moving quantum dots versus short barriers

    DEFF Research Database (Denmark)

    Utko, Pawel; Hansen, Jørn Bindslev; Lindelof, Poul Erik;

    2007-01-01

    We have investigated the response of the acoustoelectric-current driven by a surface-acoustic wave through a quantum point contact in the closed-channel regime. Under proper conditions, the current develops plateaus at integer multiples of ef when the frequency f of the surface-acoustic wave or t...

  9. Flexible Surface Hopping Approach to Model the Crossover from Hopping to Band-like Transport in Organic Crystals.

    Science.gov (United States)

    Wang, Linjun; Beljonne, David

    2013-06-06

    Two distinct pictures are usually evoked when modeling charge transport in organic crystals, that is, band and hopping models, the signature of which is conveyed by a characteristic temperature dependence of mobility. Here, we present a novel flexible surface hopping approach compliant with general Hamiltonians that is able to grasp the crossover from hopping to band-like transport regimes. This approach is applied to solve a one-dimensional mixed quantum-classical model and to calculate the temperature dependence of charge mobility along with the degree of charge spatial localization. It is found that the roles of both local and nonlocal electron-phonon couplings strongly depend on the intrinsic charge localization strength.

  10. Effect of Surface-optical Phonons on the Charge Transport in Wrap-gated Semiconducting Nanowire Field-effect Transistors

    Science.gov (United States)

    Konar, Aniruddha; Fang, Tian; Jena, Debdeep

    2010-03-01

    Surface phonons (SO-phonons) arise at the boundary of two different dielectric mediums. Though the effect of electron-surface phonon scattering on low-filed charge transport has been studied extensively for thin Si-MOSFET [1] and graphene [2], its effect on the 1D nanowire devices has not studied so far. Vibrating diploes in polar gate-dielectric induces a time-varying potential inside the nanowires. The frequencies of these time-varying fields have been calculated by implementing electrostatic boundary conditions at different interfaces of nanowire-dielectric-metal system. Our calculation shows that the electron-SO phonon interaction strength decays exponentially from the gate-nanowire interface towards the nanowire axis. Electron-SO phonon scattering rate has been calculated using Boltzmann transport equation under relaxation time approximation. We find that for thin nanowires (radius 1-20 nm), electron-SO phonon scattering rate is comparable to other dominant scattering mechanisms (such as impurity and bulk optical phonon scatterings) and reduces carrier mobility significantly. Calculating surface-phonon limited mobility of Si nanowires on various available common dielectrics, we have predicted the optimum choice of gate-dielectrics for nanowire-based electronic devices. [4pt] [1] M. V. Fischetti et. al J. Appl. Phys. 90 4581 (2001). [0pt] [2] A. Konar et. al. arXiv: 0902.0819.

  11. Animal Care Use Committees.

    Science.gov (United States)

    Snyder, Margaret D.; And Others

    1992-01-01

    Describes the structure, activities, responsibilities, and practices of animal care and use committees established to review classroom activities and student research using animals. Provides six hypothetical situations with suggested solutions to test a committee's decision-making ability. Includes a proposed activity form for teachers. (MDH)

  12. Ethics committees in Croatia

    NARCIS (Netherlands)

    Borovecki, Ana

    2007-01-01

    In this thesis the work of ethics committees in Croatia is being investigated for the first time. The 1997 Law on Health Protection introduced legal standards for the establishment of the so-called 'mixed' type of ethics committees in healthcare institutions. Our study aims to examine whether this t

  13. Turbulent momentum transport due to the beating between different tokamak flux surface shaping effects

    CERN Document Server

    Ball, Justin

    2016-01-01

    Introducing up-down asymmetry into the tokamak magnetic equilibria appears to be a feasible method to drive fast intrinsic toroidal rotation in future large devices. In this paper we investigate how the intrinsic momentum transport generated by up-down asymmetric shaping scales with the mode number of the shaping effects. Making use the gyrokinetic tilting symmetry (Ball et al (2016) Plasma Phys. Control. Fusion 58 045023), we study the effect of envelopes created by the beating of different high-order shaping effects. This reveals that the presence of an envelope can change the scaling of the momentum flux from exponentially small in the limit of large shaping mode number to just polynomially small. This enhancement of the momentum transport requires the envelope to be both up-down asymmetric and have a spatial scale on the order of the minor radius.

  14. Plasmonic Hot Electron Transport Driven Site-Specific Surface-Chemistry with Nanoscale Spatial Resolution

    CERN Document Server

    Cortés, Emiliano; Cambiasso, Javier; Jermyn, Adam S; Sundararaman, Ravishankar; Narang, Prineha; Schlücker, Sebastian; Maier, Stefan A

    2016-01-01

    Nanoscale localization of electromagnetic fields near metallic nanostructures underpins the fundamentals and applications of plasmonics. The unavoidable energy loss from plasmon decay, initially seen as a detriment, has now expanded the scope of plasmonic applications to exploit the generated hot carriers. However, quantitative understanding of the spatial localization of these hot carriers, akin to electromagnetic near-field maps, has been elusive. Here we spatially map hot-electron-driven reduction chemistry with 15 nanometre resolution as a function of time and electromagnetic field polarization for different plasmonic nanostructures. We combine experiments employing a six-electron photo-recycling process that modify the terminal group of a self-assembled monolayer on plasmonic silver nanoantennas, with theoretical predictions from first-principles calculations of non-equilibrium hot-carrier transport in these systems. The resulting localization of reactive regions, determined by hot carrier transport from...

  15. Turbulent momentum transport due to the beating between different tokamak flux surface shaping effects

    Science.gov (United States)

    Ball, Justin; Parra, Felix I.

    2017-02-01

    Introducing up-down asymmetry into the tokamak magnetic equilibria appears to be a feasible method to drive fast intrinsic toroidal rotation in future large devices. In this paper we investigate how the intrinsic momentum transport generated by up-down asymmetric shaping scales with the mode number of the shaping effects. Making use the gyrokinetic tilting symmetry (Ball et al 2016 Plasma Phys. Control. Fusion 58 045023), we study the effect of envelopes created by the beating of different high-order shaping effects. This reveals that the presence of an envelope can change the scaling of the momentum flux from exponentially small in the limit of large shaping mode number to just polynomially small. This enhancement of the momentum transport requires the envelope to be both up-down asymmetric and have a spatial scale on the order of the minor radius.

  16. Can clouds enhance long-range transport of low volatile, ionizable and surface-active chemicals?

    DEFF Research Database (Denmark)

    Franco, Antonio; Trapp, Stefan

    2011-01-01

    Atmospheric partitioning and transport of low volatile organic compounds is strongly influenced by the presence of water (e.g. clouds) and its deposition velocity (e.g. rainfall, snow). It was identified that the assumption of continuous rainfall underestimates the residence time and the transport...... substances. A modified version of the regional multimedia activity model for ionics MAMI, including twolayered atmosphere with atmospheric boundary layer (ABL) and lower/middle troposphere (LMT), interface partitioning, intermittent rainfall and variable cloud coverage was applied to a selection of ten low...... were run for a constant emission to the atmospheric boundary layer to identify key model inputs. The degradation rate, the duration of dry and wet periods and the parameters describing air-water bulk partitioning (KAW and T) and ionization (pKa and pH) determine the residence time in the ABL...

  17. New York state high-speed surface transportation study: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    In 1990, New York State Governor Mario M. Cuomo created an interagency task force under the leadership of Lt. Governor Stan Lundine to investigate the potential of high speed ground transportation (HSGT) systems. Building on information from previous agency activities, including consultant efforts contracted by the New York State Energy Research and Development Authority (NYSERDA), the New York State Thruway Authority (NYSTA), and in-house analyses performed by New York State Department of Transportation (NYSDOT), the task force focused on the corridor between New York City and the Niagara Frontier. In December 1991, NYSERDA issued a contract for a study of high speed ground transportation options for New York State. The study`s objective was to assess potential rights-of-way, ridership, energy and environmental impacts, economic benefits, capital, operating, and maintenance costs, and financial viability of HSGT systems. This study builds upon and supplements previous and on-going HSGT activities conducted by the members of the interagency task force. These activities include: Maglev Technical and Economic Feasibility Study (NYSERDA); Maglev Demonstration Site Investigation (NYSTA); and New York/Massachusetts High Speed Ground Transportation Study (NYSDOT). This study is intended to verify and refine previous information and analyses and provide supplemental information and insights to be used in determining if additional investigation and activities involving HSGT are desirable for New York State. This study evaluates HSGT technologies capable of speeds significantly higher than those achieved with the present rail system. Three HSGT categories are used in this study: incremental rail improvement, very high-speed rail, and Maglev.

  18. GPS based surface displacements – a proxy for discharge and sediment transport from the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Hasholt, Bent; Khan, Shfaqat Abbas; Mikkelsen, Andreas Bech

    2014-01-01

    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 10000 km2 segment of the Greenland Ice Sheet (GrIS) correlated very well (R2=0.83) with GPS measured uplift. Accumulated....... 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....

  19. Updated model for radionuclide transport in the near-surface till at Forsmark - Implementation of decay chains and sensitivity analyses

    Energy Technology Data Exchange (ETDEWEB)

    Pique, Angels; Pekala, Marek; Molinero, Jorge; Duro, Lara; Trinchero, Paolo; Vries, Luis Manuel de [Amphos 21 Consulting S.L., Barcelona (Spain)

    2013-02-15

    The Forsmark area has been proposed for potential siting of a deep underground (geological) repository for radioactive waste in Sweden. Safety assessment of the repository requires radionuclide transport from the disposal depth to recipients at the surface to be studied quantitatively. The near-surface quaternary deposits at Forsmark are considered a pathway for potential discharge of radioactivity from the underground facility to the biosphere, thus radionuclide transport in this system has been extensively investigated over the last years. The most recent work of Pique and co-workers (reported in SKB report R-10-30) demonstrated that in case of release of radioactivity the near-surface sedimentary system at Forsmark would act as an important geochemical barrier, retarding the transport of reactive radionuclides through a combination of retention processes. In this report the conceptual model of radionuclide transport in the quaternary till at Forsmark has been updated, by considering recent revisions regarding the near-surface lithology. In addition, the impact of important conceptual assumptions made in the model has been evaluated through a series of deterministic and probabilistic (Monte Carlo) sensitivity calculations. The sensitivity study focused on the following effects: 1. Radioactive decay of {sup 135}Cs, {sup 59}Ni, {sup 230}Th and {sup 226}Ra and effects on their transport. 2. Variability in key geochemical parameters, such as the composition of the deep groundwater, availability of sorbing materials in the till, and mineral equilibria. 3. Variability in hydraulic parameters, such as the definition of hydraulic boundaries, and values of hydraulic conductivity, dispersivity and the deep groundwater inflow rate. The overarching conclusion from this study is that the current implementation of the model is robust (the model is largely insensitive to variations in the parameters within the studied ranges) and conservative (the Base Case calculations have a

  20. Solution processed deposition of electron transport layers on perovskite crystal surface-A modeling based study

    Science.gov (United States)

    Mortuza, S. M.; Taufique, M. F. N.; Banerjee, Soumik

    2017-02-01

    The power conversion efficiency (PCE) of planar perovskite solar cells (PSCs) has reached up to ∼20%. However, structural and chemicals defects that lead to hysteresis in the perovskite based thin film pose challenges. Recent work has shown that thin films of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) deposited on the photo absorption layer, using solution processing techniques, minimize surface pin holes and defects thereby increasing the PCE. We developed and employed a multiscale model based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) to establish a relationship between deposition rate and surface coverage on perovskite surface. The MD simulations of PCBMs dispersed in chlorobenzene, sandwiched between (110) perovskite substrates, indicate that PCBMs are deposited through anchoring of the oxygen atom of carbonyl group to the exposed lead (Pb) atom of (110) perovskite surface. Based on rates of distinct deposition events calculated from MD, kMC simulations were run to determine surface coverage at much larger time and length scales than accessible by MD alone. Based on the model, a generic relationship is established between deposition rate of PCBMs and surface coverage on perovskite crystal. The study also provides detailed insights into the morphology of the deposited film.

  1. Transport of Substances on Different Stages of Processes Initiated by Free Fallen Drop Impact on Surface of Quiescent Water

    Science.gov (United States)

    Ilyinykh, A. Yu.

    2012-04-01

    Collision of a free fallen drop with a surface of quiescent layer of water initiates a sequence of processes including initial shock, formation of cavern and crown with a chevron edge emitted small water drops, wide central trough surrounding by a train of running surface circular capillary waves, splash, secondary cavern collapsing with a streamer discharge and gradual decal of all disturbances. Fine structure of the drop splashes and transport of substances carrying by the drop inside accepting target fluid are studied by methods of direct registering of flow images by fast video- and photo cameras. Different directions of observations were realized that are side, top and bottom view of flow patterns. Flow patterns produced by clean and coloured water, alcohol (changing the surface tension) and oil drops were investigated. Attention was concentrated on small scale processes dynamics studying which produce fast variations of water surface shapes with sharp local irregularities. Shapes and textures of craters and surrounding rim surfaces as well as coloured filaments of a drop substance inside the fluid body were registered and analyzed. Two groups of flows with relatively large scales defined by the drop diameter and very fine scales were identified. It is supposed that short living and fast changing flow components are result of strong short-acting forces impact. Their manifestations depend on surface tension on the boundaries fluid-fluid and fluid-air. Effects of surface tension gradients on the drop dye propagation pattern are also demonstrated and discussed. Experiments were performed on set-up USU "HPC IPMec RAS" under support of Ministry of Education and Science RF (Goscontract No. 16.518.11.7059).

  2. Quantum transport equation for systems with rough surfaces and its application to ultracold neutrons in a quantizing gravity field

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, M.; Meyerovich, A. E., E-mail: Alexander-Meyerovich@uri.edu [University of Rhode Island, Department of Physics (United States)

    2014-12-15

    We discuss transport of particles along random rough surfaces in quantum size effect conditions. As an intriguing application, we analyze gravitationally quantized ultracold neutrons in rough waveguides in conjunction with GRANIT experiments (ILL, Grenoble). We present a theoretical description of these experiments in the biased diffusion approximation for neutron mirrors with both one- and two-dimensional (1D and 2D) roughness. All system parameters collapse into a single constant which determines the depletion times for the gravitational quantum states and the exit neutron count. This constant is determined by a complicated integral of the correlation function (CF) of surface roughness. The reliable identification of this CF is always hindered by the presence of long fluctuation-driven correlation tails in finite-size samples. We report numerical experiments relevant for the identification of roughness of a new GRANIT waveguide and make predictions for ongoing experiments. We also propose a radically new design for the rough waveguide.

  3. The Helium Field Effect Transistor (II): Gated Transport of Surface-State Electrons Through Micro-constrictions

    Science.gov (United States)

    Shaban, F.; Ashari, M.; Lorenz, T.; Rau, R.; Scheer, E.; Kono, K.; Rees, D. G.; Leiderer, P.

    2016-11-01

    We present transport measurements of surface-state electrons on liquid helium films in confined geometry. The measurements are taken using split-gate devices similar to a field effect transistor. The number of electrons passing between the source and drain areas of the device can be precisely controlled by changing the length of the voltage pulse applied to the gate electrode. We find evidence that the effective driving potential depends on electron-electron interactions, as well as the electric field applied to the substrate. Our measurements indicate that the mobility of electrons on helium films can be high and that microfabricated transistor devices allow electron manipulation on length scales close to the interelectron separation. Our experiment is an important step toward investigations of surface-state electron properties at much higher densities, for which the quantum melting of the system to a degenerate Fermi gas should be observed.

  4. The Compensation Committee. Effective Committees. Board Basics.

    Science.gov (United States)

    Tranquada, Robert E.

    2001-01-01

    This booklet describes some of the practices of committees charged with setting the compensation of the college or university president or chancellor. Whether the institution is private or public, the president's income will become public information, and apart from any public relations implications, it simply makes good sense for the compensation…

  5. Effect of low-concentration rhamnolipid on transport of Pseudomonas aeruginosa ATCC 9027 in an ideal porous medium with hydrophilic or hydrophobic surfaces.

    Science.gov (United States)

    Zhong, Hua; Liu, Guansheng; Jiang, Yongbing; Brusseau, Mark L; Liu, Zhifeng; Liu, Yang; Zeng, Guangming

    2016-03-01

    The success of effective bioaugmentation processes for remediation of soil and groundwater contamination requires effective transport of the injected microorganisms in the subsurface environment. In this study, the effect of low concentrations of monorhamnolipid biosurfactant solutions on transport of Pseudomonas aeruginosa in an ideal porous medium (glass beads) with hydrophilic or hydrophobic surfaces was investigated by conducting miscible-displacement experiments. Transport behavior was examined for both glucose-grown and hexadecane-grown cells, with low and high surface hydrophobicity, respectively. A clean-bed colloid deposition model was used for determination of deposition rate coefficients. Results show that cells with high surface hydrophobicity exhibit greater retention than cells with low surface hydrophobicity. Rhamnolipid affects cell transport primarily by changing cell surface hydrophobicity, with an additional minor effect by increasing solution ionic strength. There is a good linear relation between k and rhamnolipid-regulated cell surface hydrophobicity presented as bacterial-adhesion-to-hydrocarbon (BATH) rate of cells (R(2)=0.71). The results of this study show the importance of hydrophobic interaction for transport of bacterial cells in silica-based porous media, and the potential of using low-concentration rhamnolipid solutions for facilitating bacterial transport in bioaugmentation efforts.

  6. Prediction of Flow and Solute Transport in Fractured Media: Comparison of Metrics to Describe Effects of Rough Surfaces

    Science.gov (United States)

    Slottke, D.; Ketcham, R. A.; Sharp, J. M.

    2008-05-01

    Fractures dominate fluid flow and transport of solutes when they are open and connected. The prediction of flow through fractured media has implications for development of water resources, petroleum reservoir exploitation, contamination and remediation assessment, and site evaluation for waste repositories. Assessing the impact of surface roughness on fluid flow and solute transport through fractured media from samples on the order of 100 cm2 assumes the existence of a relationship between fracture morphology and discharge that is scale invariant or at least smoothly transformable. Although some studies assume that the length scale at which surface roughness significantly contributes to the discharge through a fracture falls within the size of a typical hand sample, there is a dearth of empirical data supporting an extension of the relationships found at small scales to larger samples. Furthermore, an appropriate metric to describe a fracture volume accurately must be chosen. We compile data from physical flow tests and numerical modeling of two discrete natural fractures of different scales in rhyolitc tuff. The University of Texas HRXCT facility provided computed tomography representations of the fractures that allow analysis of surface roughness and aperture statistics at 0.25mm grid resolution, which form the basis for transmissivity field inputs to numerical models. We show that although a small (10cm2) representative surface can describe roughness, aperture fields are not so well behaved. We compare physical flow test results, modeled flow, and analytical solutions of the cubic law using various methods of assigning a meaningful aperture to illustrate the challenges of accurate modeling of fracture flow without a priori flow information. While a geometric mean aperture of the entire aperture field closely approximates the hydraulic aperture, an arbitrary profile mean aperture has little utility for predictive purposes.

  7. A putative cell surface receptor for white spot syndrome virus is a member of a transporter superfamily.

    Directory of Open Access Journals (Sweden)

    Huai-Ting Huang

    Full Text Available White spot syndrome virus (WSSV, a large enveloped DNA virus, can cause the most serious viral disease in shrimp and has a wide host range among crustaceans. In this study, we identified a surface protein, named glucose transporter 1 (Glut1, which could also interact with WSSV envelope protein, VP53A. Sequence analysis revealed that Glut1 is a member of a large superfamily of transporters and that it is most closely related to evolutionary branches of this superfamily, branches that function to transport this sugar. Tissue tropism analysis showed that Glut1 was constitutive and highly expressed in almost all organs. Glut1's localization in shrimp cells was further verified and so was its interaction with Penaeus monodon chitin-binding protein (PmCBP, which was itself identified to interact with an envelope protein complex formed by 11 WSSV envelope proteins. In vitro and in vivo neutralization experiments using synthetic peptide contained WSSV binding domain (WBD showed that the WBD peptide could inhibit WSSV infection in primary cultured hemocytes and delay the mortality in shrimps challenged with WSSV. These findings have important implications for our understanding of WSSV entry.

  8. Tracking of magnetic flux concentrations over a five-day observation, and an insight into surface magnetic flux transport

    Directory of Open Access Journals (Sweden)

    Iida Yusuke

    2016-01-01

    Full Text Available The solar dynamo problem is the question of how the cyclic variation in the solar magnetic field is maintained. One of the important processes is the transport of magnetic flux by surface convection. To reveal this process, the dependence of the squared displacement of magnetic flux concentrations on the elapsed time is investigated in this paper via a feature-recognition technique and a continual five-day magnetogram. This represents the longest time scale over which a satellite observation has ever been performed for this problem. The dependence is found to follow a power law and differ significantly from that of diffusion transport. Furthermore, there is a change in the behavior at a spatial scale of 103.8 km. A super-diffusion behavior with an index of 1.4 is found at smaller scales, while changing to a sub-diffusion behavior with an index of 0.6 on larger ones. We interpret this difference in the transport regime as coming from the network-flow pattern.

  9. Transport properties governed by surface barriers in Bi2Sr2CaCu2O8

    Science.gov (United States)

    Fuchs, Dan T.; Zeldov, Eli; Rappaport, Michael; Tamegai, Tsuyoshi; Ooi, Shuuichi; Shtrikman, Hadas

    1998-01-01

    One of the most common investigation techniques of type-II superconductors is the transport measurement, in which an electrical current is applied to a sample and the corresponding resistance is measured as a function of temperature and magnetic field. At temperatures well below the critical temperature, Tc, the resistance of a superconductor is usually immeasurably low. But at elevated temperatures and fields, in the so-called vortex liquid phase, a substantial linear resistance is observed. In this dissipative state, which in anisotropic high-temperature superconductors like Bi2Sr2CaCu2O8 may occupy most of the mixed-state phase diagram, the transport current is usually assumed to flow uniformly across the sample as in a normal metal. To test this assumption, we have devised a measurement approach which allows determination of the flow pattern of the transport current across the sample. The surprising result is that, in Bi2Sr2CaCu2O8 crystals, most of the current flows at the edges of the sample rather than in the bulk, even in the highly resistive state, due to the presence of strong surface barriers. This finding has significant implications for the interpretation of existing resistivity data and may be of importance for the development of high-temperature superconducting wires and tapes.

  10. Tracking of magnetic flux concentrations over a five-day observation and an insight into surface magnetic flux transport

    CERN Document Server

    Iida, Y

    2016-01-01

    The solar dynamo problem is the question of how the cyclic variation in the solar magnetic field is maintained. One of the important processes is the transport of magnetic flux by surface convection. To reveal this process, the dependence of the squared displacement of magnetic flux concentrations upon the elapsed time is investigated in this paper via a feature-recognition technique and a continual five-day magnetogram. This represents the longest time scale over which a satellite observation has ever been performed for this problem. The dependence is found to follow a power-law and differ significantly from that of diffusion transport. Furthermore there is a change in the behavior at a spatial scale of 10^{3.8} km. A super-diffusion behavior with an index of 1.4 is found on smaller scales, while changing to a sub-diffusion behavior with an index of 0.6 on larger ones. I interpret this difference in the transport regime as coming from the network-flow pattern.

  11. Circular dichroism and superdiffusive transport at the surface of BiTeI.

    Science.gov (United States)

    Mauchain, J; Ohtsubo, Y; Hajlaoui, M; Papalazarou, E; Marsi, M; Taleb-Ibrahimi, A; Faure, J; Kokh, K A; Tereshchenko, O E; Eremeev, S V; Chulkov, E V; Perfetti, L

    2013-09-20

    We investigate the electronic states of BiTeI after the optical pumping with circularly polarized photons. Our data show that photoexcited electrons reach an internal thermalization within 300 fs of the arrival of the pump pulse. Instead, the dichroic contrast generated by the circularly polarized light relaxes on a time scale shorter than 80 fs. This result implies that orbital and spin polarization created by the circular pump pulse rapidly decays via manybody interaction. The persistent dichroism at longer delay times is due to the helicity dependence of superdiffussive transport. We ascribe it to the lack of inversion symmetry in an electronic system far from equilibrium conditions.

  12. Soil surface searching and transport of Euphorbia characias seeds by ants

    Science.gov (United States)

    Espadaler, Xavier; Gómez, Crisanto

    The intensity of exploring the soil surface by ants was studied for the four species involved in the dispersal and predation of seeds of the West-Mediterranean myrmecochorous plant Euphorbia characias. During the dehiscence period (June) the whole soil surface is sccanned in 43 minutes. Not all ants that find a seed take it to the nest. For the four ant species studied ( Pheidole pallidula, Aphaenogaster senilis, Tapinoma nigerrimum, Messor barbarus) the proportion of ants that finally take the seed is 67.6%. In spite of this, the high level of soil surface searching explains the rather short time that seeds remain on the soil before being removed. The presence of an elaiosome is a key element in the outcome of the ant-seed interaction: a seed with elaiosome has a seven-fold increase in probability of being taken to the nest if found by a non-granivorous ant. The predator-avoidance hypothesis for myrmecochory is supported.

  13. The Effect of Diffusional Transport and Surface Catalysis on the Aerothermodynamic Heating for Martian Atmospheric Entry

    Science.gov (United States)

    Henline, William D.; Papadopoulos, Periklis; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    For the reentry heating of 70-degree blunt sphere-cones entering Mars at velocities in excess of 6 km/sec, a study was performed to determine the magnitude of both convective and catalytic heating on the cone forebody. Case studies of the peak heating conditions for the current NASA Mars Pathfinder entry probe, as well as the peak heating conditions of the proposed NASA Mars 2001 aerobraking orbiter mission were performed. Since the actual behavior of the chemical recombination of Mars atmosphere hypersonic shock layer species on heat shield materials is not known, and no experimental studies of any consequence have been done to determine surface reaction rates for the CO2 system, a parametric analysis of various reaction schemes and surface catalytic mechanistic models was performed. In many cases the actual Mars entry probe will have a heat shield composed of an ablative material which can either partially or completely preclude the existence of catalytic surface recombination phenomena. The extent of this blockage effect has not been examined at this time and is not considered in this effort. Instead only non-ablative computations are performed to separately evaluate the full extent of the surface catalysis and related diffusional phenomena. Parametric studies include peak heating point comparisons of non-catalytic, partially catalytic and fully catalytic total surface heat transfer for three difference surface recombination catalytic mechanisms (with and without simultaneous CO + O and O + O recombination) as well as with different species diffusion models. Diffusion model studies include constant Schmidt number (equal diffusivities) and the bifurcation, approximate multi-component diffusion model. Since the gas phase reaction kinetics for the Mars CO2 based atmosphere have also not been validated, the effect of two different (fast and slow) sets of gas kinetics on heat transfer is presented.

  14. Efficient Coupling and Transport of a Surface Plasmon at 780 nm in a Gold Nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; Joly, Alan G.; El-Khoury, Patrick Z.; Hess, Wayne P.

    2015-08-28

    We studied plasmonic nanostructures in single-crystal gold with scanning electron and femtosecond photoemission electron microscopies. We designed an integrated laser coupling and nanowire waveguide structure by focused ion beam lithography in single-crystal gold flakes. The photoemission results show that the laser field is efficiently coupled into a propagating surface plasmon by a simple hole structure and propagates efficiently in an adjacent nano-bar waveguide. A strong local field is created by the propagating surface plasmon at the nano-bar tip. A similar structure, with a decreased waveguide width and thickness, displayed significantly more intense photoemission indicating enhanced local electric field at the sharper tip.

  15. Electronic transport through Si nanowires: Role of bulk and surface disorder

    DEFF Research Database (Denmark)

    Markussen, Troels; Rurali, R.; Brandbyge, Mads

    2006-01-01

    on the situation a preferable method can be identified. Several numerical results are presented to illustrate the relative merits of the two methods. Our calculations of relaxed atomic structures and their conductance properties are based on density functional theory without introducing adjustable parameters. Two...... specific models of disorder are considered: Unpassivated, surface reconstructed SiNW's are perturbed by random on-site (Anderson) disorder whereas defects in hydrogen passivated wires are introduced by randomly removed H atoms. The unpassivated wires are very sensitive to disorder in the surface whereas...

  16. Transport of a nematicide in surface and ground waters in a farmed tropical catchment with volcanic substratum

    Science.gov (United States)

    Charlier, J.-B.; Cattan, P.; Voltz, M.; Moussa, R.

    2009-04-01

    Assessment of water-pollution risks in agricultural regions requires studying pesticide transport processes in soil and water compartments at the catchment scale. In tropical regions, banana (Musa spp.) plantations are located in zones with abundant rainfalls and soils with high infiltration rates, which lead to washout and leaching of soil-applied pesticides, causing severe diffuse pollution of water resources. The aim of this paper is to determine how the nematicide cadusafos [S,S-di-sec-butyl O-ethyl phosphorodithioate], used in banana plantations, contaminates water and soils at the two scales of subcatchment and catchment. The study site was a small banana-growing catchment on the tropical volcanic island of Guadeloupe in the Caribbean (FWI). The catchment is located in pedoclimatic conditions where rainfall is abundant (> 4000 mm/year), and soil permeable (saturated hydraulic conductivity of Andosol Ks > 30 mm/h). Two campaigns of nematicide application were conducted, one in 2003 over 40% of the catchment and one in 2006 over 12%. For 100 days after application, we monitored the surface water and groundwater flows and the cadusafos concentrations in the soil and in surface and ground waters in a 2400 m² subcatchment and a 17.8 ha catchment. The results show that at the subcatchment scale the high retention in the A horizon of the soil limited the transport of cadusafos by runoff, whereas the lower retention of the molecule in the B horizon favoured percolation towards the shallow groundwater. The contamination levels of surface water, as well as shallow and deep groundwaters, reflected the geological structure of the Féfé catchment: i.e. a shallow aquifer in the most recent volcanic deposits that is rapidly exposed to pollution and a deeper aquifer that is relatively protected from the pollution coming from the treated fields. Comparing the losses of cadusafos at the subcatchment and at the catchment scales revealed that the nematicide re-infiltrated in

  17. Turbulent coherent-structure dynamics in a natural surface storage zone: Mechanisms of mass and momentum transport in rivers

    Science.gov (United States)

    Escauriaza, Cristian; Sandoval, Jorge; Mignot, Emmanuel; Mao, Luca

    2016-11-01

    Turbulent flows developed in surface storage zones (SSZ) in rivers control many physical and biogeochemical processes of contaminants in the water. These regions are characterized by low velocities and long residence times, which favor particle deposition, nutrient uptake, and flow interactions with reactive sediments. The dynamics of the flow in SSZ is driven by a shear layer that induces multiple vortical structures with a wide range of temporal and spatial scales. In this work we study the flow in a lateral SSZ of the Lluta River, a high-altitude Andean stream (4,000 masl), with a Re=45,800. We describe the large-scale turbulent coherent structures using field measurements and 3D numerical simulations. We measure the bed topography, instantaneous 3D velocities at selected points, the mean 2D free-surface velocity field, and arsenic concentration in the sediment. Numerical simulations of the flow are also performed using a DES turbulence model. We focus on the mass and momentum transport processes, analyzing the statistics of mass exchange and residence times in the SSZ. With this information we provide new insights on the flow and transport processes between the main channel and the recirculating region in natural conditions. Supported by Fondecyt 1130940.

  18. The effects of the accuracy of the atmospheric forcings on the prediction of the sea surface transport in coastal areas.

    Science.gov (United States)

    Cucco, Andrea; Quattrocchi, Giovanni; Satta, Andrea; Antognarelli, Fabio; della Valle, Antonio; De Biasio, Francesco; Cadau, Enrico; Zecchetto, Stefano; Umgiesser, Georg

    2015-04-01

    In the framework of the Italian flagship project RITMARE (http://www.ritmare.it/en/) an Operational Oceanography Systems (OOS hereafter) based on high resolution 3D hydrodynamic model has been developed for the Oristano Gulf (Sardinia, Italy), with the aim of making short term predictions of water currents and pollutant transport. Atmospheric data provided by the SKIRON meteorological model system (http://forecast.uoa.gr/) were used to make the predictions. In order to asses the quality of the wind field adopted to force the hydrodynamic model, a coastal wind measuring system (WMS hereafter) was developed. The WMS is composed by five three-components anemometers located along the Gulf coasts, which provide hourly and operationally wind measurements. These data are then used operationally to derive high resolution wind fields over the entire Gulf and surrounding coastal areas. The modelled wind data have been compared with the measured ones and the meteorological model accuracy estimated. A set of lagrangian buoys were deployed within the Gulf to measure the sea surface transport due to the main local wind regimes. The OOS were used to reproduce the paths followed by each lagrangian buoy using as forcing conditions both the wind fields measured by the local WMS and the predicted ones. Therefore the effects of the atmospheric forcing quality on predicting the surface hydrodynamics at coastal scale were determined.

  19. Ab-Initio Modelling Of Surface Site Reactivity And Fluid Transport In Clay Minerals Case Study: Pyrophyllite

    Energy Technology Data Exchange (ETDEWEB)

    Churakov, S.V

    2005-03-01

    Pyrophyllite, Al{sub 2}[Si{sub 4}O{sub 10}](OH){sub 2}, is the simplest structural prototype for 2:1 dioctahedral phyllosilicate. Because the net electric charge in pyrophyllite is zero, it is the best candidate for investigating the non electrostatic contribution to sorption and transport phenomena in clays. Using ab-initio simulations, we have investigated the reactivity and structure of the water-solid interface on the basal plane and edge sites of pyrophyllite. The calculations predict slightly hydrophobic behaviour of the basal plane. For the high water coverage (100), (110) and (-110), lateral facets have a lower energy than for the (010), (130) and (-130) surfaces. Analysis of the surface reactivity reveals that the =Al-OH groups are most easily protonated on the (010), (130) and (-130) facets. The =Al-O-Si= sites will be protonated on the (100), (130), (110), (-110) and (-130) surfaces. The =Al-OH{sub 2} complexes are more easily de-protonated than the =Si-OH and =Al-OH sites. A spontaneous, reversible exchange of the protons between the solution and the edge sites has been observed in ab-initio molecular dynamics simulations at 300 K. Such near-surface proton diffusion may result in a significant contribution to the diffusion coefficients measured in neutron scattering experiments. (author)

  20. Electrowetting actuated microfluidic transport in surface grooves with triangular cross section.

    Science.gov (United States)

    Barman, Jitesh; Swain, Digendranath; Law, Bruce M; Seemann, Ralf; Herminghaus, Stephan; Khare, Krishnacharya

    2015-01-27

    Liquids show different static wetting morphologies in open triangular grooves depending upon the wedge angle (ψ) of the groove and the liquid contact angle (θ) with the substrate. Switching between different morphologies can be achieved either by varying the contact angle of the liquid or by changing the wedge angle of the groove. In the present work we manipulate the apparent contact angle of a liquid by electrowetting to switch between liquid morphologies, from droplet to filament, to achieve microfluidic transport of the liquid into open triangular grooves. The static length of liquid filaments in grooves is analyzed as a function of applied voltage for different applied ac frequencies. The dynamic advancement of the filament lengths in grooves is analyzed as a function of time for different applied voltages for two different liquids: first with contact angle greater than the wedge angle and second with contact angle smaller than the wedge angle. Later an exact electrical model is derived to explain the liquid transport in triangular grooves actuated by electrowetting which includes the precise geometry of the liquid morphology.

  1. FOB-SH: Fragment orbital-based surface hopping for charge carrier transport in organic and biological molecules and materials

    Science.gov (United States)

    Spencer, J.; Gajdos, F.; Blumberger, J.

    2016-08-01

    We introduce a fragment orbital-based fewest switches surface hopping method, FOB-SH, designed to efficiently simulate charge carrier transport in strongly fluctuating condensed phase systems such as organic semiconductors and biomolecules. The charge carrier wavefunction is expanded and the electronic Hamiltonian constructed in a set of singly occupied molecular orbitals of the molecular sites that mediate the charge transfer. Diagonal elements of the electronic Hamiltonian (site energies) are obtained from a force field, whereas the off-diagonal or electronic coupling matrix elements are obtained using our recently developed analytic overlap method. We derive a general expression for the exact forces on the adiabatic ground and excited electronic state surfaces from the nuclear gradients of the charge localized electronic states. Applications to electron hole transfer in a model ethylene dimer and through a chain of ten model ethylenes validate our implementation and demonstrate its computational efficiency. On the larger system, we calculate the qualitative behaviour of charge mobility with change in temperature T for different regimes of the intermolecular electronic coupling. For small couplings, FOB-SH predicts a crossover from a thermally activated regime at low temperatures to a band-like transport regime at higher temperatures. For higher electronic couplings, the thermally activated regime disappears and the mobility decreases according to a power law. This is interpreted by a gradual loss in probability for resonance between the sites as the temperature increases. The polaron hopping model solved for the same system gives a qualitatively different result and underestimates the mobility decay at higher temperatures. Taken together, the FOB-SH methodology introduced here shows promise for a realistic investigation of charge carrier transport in complex organic, aqueous, and biological systems.

  2. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NARCIS (Netherlands)

    Sedao, X.; Derrien, T.J.Y.; Romer, G.W.R.B.E.; Pathiraj, B.; Huis in 't Veld, A.J.

    2012-01-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array assemb

  3. Ultrahigh-frequency surface acoustic wave generation for acoustic charge transport in silicon

    NARCIS (Netherlands)

    Büyükköse, S.; Vratzov, B.; van der Veen, Johan (CTIT); Santos, P.V.; van der Wiel, Wilfred Gerard

    2013-01-01

    We demonstrate piezo-electrical generation of ultrahigh-frequency surface acoustic waves on silicon substrates, using high-resolution UV-based nanoimprint lithography, hydrogen silsequioxane planarization, and metal lift-off. Interdigital transducers were fabricated on a ZnO layer sandwiched between

  4. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores t

  5. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NARCIS (Netherlands)

    Sedao, X.; Derrien, T.J.Y.; Romer, G.W.R.B.E.; Pathiraj, B.; Huis in 't Veld, A.J.

    2012-01-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array

  6. Interactions between bacteria and solid surfaces in relation to bacterial transport in porous media

    NARCIS (Netherlands)

    Rijnaarts, H.H.M.

    1994-01-01

    Interactions between bacteria and solid surfaces strongly influence the behaviour of bacteria in natural and engineered ecosystems. Many biofilm reactors and terrestrial environments are porous media. The purpose of the research presented in this thesis is to gain a better insight into the

  7. Phosphate availability in the soil-root system: integration of oxide surface chemistry, transport and uptake.

    NARCIS (Netherlands)

    Geelhoed, J.S.

    1998-01-01

    A study is presented on the adsorption of phosphate on goethite, the interaction of phosphate with other adsorbing ions at the goethite surface, and the resulting availability of phosphate to plants. The plant-availability of sorbed phosphate was determined from phosphorus uptake of plants growing o

  8. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores t

  9. Interactions between bacteria and solid surfaces in relation to bacterial transport in porous media.

    NARCIS (Netherlands)

    Rijnaarts, H.H.M.

    1994-01-01

    Interactions between bacteria and solid surfaces strongly influence the behaviour of bacteria in natural and engineered ecosystems. Many biofilm reactors and terrestrial environments are porous media. The purpose of the research presented in this thesis is to gain a better insight into the basic mec

  10. Self-assembled monolayers based spintronics: from ferromagnetic surface functionalization to spin-dependent transport.

    Science.gov (United States)

    Tatay, Sergio; Galbiati, Marta; Delprat, Sophie; Barraud, Clément; Bouzehouane, Karim; Collin, Sophie; Deranlot, Cyrile; Jacquet, Eric; Seneor, Pierre; Mattana, Richard; Petroff, Frédéric

    2016-03-09

    Chemically functionalized surfaces are studied for a wide range of applications going from medicine to electronics. Whereas non-magnetic surfaces have been widely studied, functionalization of magnetic surfaces is much less common and has almost never been used for spintronics applications. In this article we present the functionalization of La2/3Sr1/3MnO3, a ferromagnetic oxide, with self-assembled monolayers for spintronics. La2/3Sr1/3MnO3 is the prototypical half-metallic manganite used in spintronics studies. First, we show that La2/3Sr1/3MnO3 can be functionalized by alkylphosphonic acid molecules. We then emphasize the use of these functionalized surfaces in spintronics devices such as magnetic tunnel junctions fabricated using a nano-indentation based lithography technique. The observed exponential increase of tunnel resistance as a function of alkyl chain length is a direct proof of the successful connection of molecules to ferromagnetic electrodes. For all alkyl chains studied we obtain stable and robust tunnel magnetoresistance, with effects ranging from a few tens to 10 000%. These results show that functionalized electrodes can be integrated in spintronics devices and open the door to a molecular engineering of spintronics.

  11. Microscopic droplet formation and energy transport analysis of condensation on scalable superhydrophobic nanostructured copper oxide surfaces.

    Science.gov (United States)

    Li, GuanQiu; Alhosani, Mohamed H; Yuan, ShaoJun; Liu, HaoRan; Ghaferi, Amal Al; Zhang, TieJun

    2014-12-01

    Utilization of nanotechnologies in condensation has been recognized as one opportunity to improve the efficiency of large-scale thermal power and desalination systems. High-performance and stable dropwise condensation in widely-used copper heat exchangers is appealing for energy and water industries. In this work, a scalable and low-cost nanofabrication approach was developed to fabricate superhydrophobic copper oxide (CuO) nanoneedle surfaces to promote dropwise condensation and even jumping-droplet condensation. By conducting systematic surface characterization and in situ environmental scanning electron microscope (ESEM) condensation experiments, we were able to probe the microscopic formation physics of droplets on irregular nanostructured surfaces. At the early stages of condensation process, the interfacial surface tensions at the edge of CuO nanoneedles were found to influence both the local energy barriers for microdroplet growth and the advancing contact angles when droplets undergo depinning. Local surface roughness also has a significant impact on the volume of the condensate within the nanostructures and overall heat transfer from the vapor to substrate. Both our theoretical analysis and in situ ESEM experiments have revealed that the liquid condensate within the nanostructures determines the amount of the work of adhesion and kinetic energy associated with droplet coalescence and jumping. Local and global droplet growth models were also proposed to predict how the microdroplet morphology within nanostructures affects the heat transfer performance of early-stage condensation. Our quantitative analysis of microdroplet formation and growth within irregular nanostructures provides the insight to guide the anodization-based nanofabrication for enhancing dropwise and jumping-droplet condensation performance.

  12. Potential problems with environmental sound barriers when used in mitigating surface transportation noise.

    Science.gov (United States)

    Arenas, Jorge P

    2008-11-01

    The public, increasingly well-informed about the problem of excessive noise, is taking actions for the development of new transport infrastructure projects and improvement of existing infrastructure. In addition, many countries have implemented mandatory Environmental Impact Assessment procedures. As a result, the construction of sound barriers has become a common measure, which can be used by an agency to mitigate potentially significant noise impacts. A sound barrier, eventually, will become part of the surrounding landscape and could be a cause of impact for ecosystems, the road users and those who live alongside the road. Basically, this article discusses these potential effects in the context of environmental assessment procedures. In addition, results of a pilot survey conducted at a residential area affected by the construction of a barrier are presented. Although most residents felt that sleeping conditions improved after the barrier was built, most important negative reactions are the loss of sunlight and visual impact.

  13. Fate and transport of glyphosate and aminomethylphosphonic acid in surface waters of agricultural basins

    Science.gov (United States)

    Gregoire, Caroline; Capel, Paul D.; Coupe, Richard H.; Kalkhoff, Stephen J.

    2011-01-01

    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.

  14. Nanofluidic Transport over a Curved Surface with Viscous Dissipation and Convective Mass Flux

    Science.gov (United States)

    Mehmood, Zaffar; Iqbal, Z.; Azhar, Ehtsham; Maraj, E. N.

    2017-03-01

    This article is a numerical investigation of boundary layer flow of nanofluid over a bended stretching surface. The study is carried out by considering convective mass flux condition. Contribution of viscous dissipation is taken into the account along with thermal radiation. Suitable similarity transformations are employed to simplify the system of nonlinear partial differential equations into a system of nonlinear ordinary differential equations. Computational results are extracted by means of a shooting method embedded with a Runge-Kutta Fehlberg technique. Key findings include that velocity is a decreasing function of curvature parameter K. Moreover, Nusselt number decreases with increase in curvature of the stretching surface while skin friction and Sherwood number enhance with increase in K.

  15. Volatile transport on inhomogeneous surfaces: II. Numerical calculations (VT3D)

    CERN Document Server

    Young, Leslie A

    2015-01-01

    Several distant icy worlds have atmospheres that are in vapor-pressure equilibrium with their surface volatiles, including Pluto, Triton, and, probably, several large KBOs near perihelion. Studies of the volatile and thermal evolution of these have been limited by computational speed, especially for models that treat surfaces that vary with both latitude and longitude. In order to expedite such work, I present a new numerical model for the seasonal behavior of Pluto and Triton which (i) uses initial conditions that improve convergence, (ii) uses an expedient method for handling the transition between global and non-global atmospheres, (iii) includes local conservation of energy and global conservation of mass to partition energy between heating, conduction, and sublimation or condensation, (iv) uses time-stepping algorithms that ensure stability while allowing larger timesteps, and (v) can include longitudinal variability. This model, called VT3D, has been used in Young (2012), Young (2013), Olkin et al. (201...

  16. Nanofluidic transport over a curved surface with viscous dissipation and convective mass flux

    Energy Technology Data Exchange (ETDEWEB)

    Mehmood, Zaffar; Iqbal, Z.; Azhar, Ehtsham; Maraj, E.N. [HITEC Univ., Taxila (Pakistan). Dept. of Mathematics

    2017-06-01

    This article is a numerical investigation of boundary layer flow of nanofluid over a bended stretching surface. The study is carried out by considering convective mass flux condition. Contribution of viscous dissipation is taken into the account along with thermal radiation. Suitable similarity transformations are employed to simplify the system of nonlinear partial differential equations into a system of nonlinear ordinary differential equations. Computational results are extracted by means of a shooting method embedded with a Runge-Kutta Fehlberg technique. Key findings include that velocity is a decreasing function of curvature parameter K. Moreover, Nusselt number decreases with increase in curvature of the stretching surface while skin friction and Sherwood number enhance with increase in K.

  17. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2010-01-01

    Main issues examined at the meeting of 2 October 2009 The October 2009 meeting of the Standing Concertation Committee was entirely devoted to preparation of TREF’s meeting on 21-22 October. The Committee took note of, discussed and agreed on clarifications needed to some of the documents and presentations that the Management intended to submit and/or present to TREF on the following subjects: Equal opportunities The Committee took note of a preliminary report on equal opportunities at CERN drawn up by D. Chromek-Burckhart, the Equal Opportunities Officer, and T. Smith, Chairman of the Equal Opportunities Advisory Panel, containing in particular a proposal for a new process for resolving harassment conflicts. Technical analysis of the CERN Health Insurance Scheme - Actuary’s Report The Committee took note of a presentation by P. Charpentier, Chairman of the CERN Health Insurance Supervisory Board (CHIS Board), on the 2009 actuarial report on the CERN Health Insurance Scheme (CHIS). Th...

  18. The Chinese Olympic Committee

    Institute of Scientific and Technical Information of China (English)

    余信波

    2008-01-01

    The Chinese Olympic Committee (COC) is a non-governmental,non-profit national sports organization of a mass character,with the objective of developing sports and promoting the Olympic Movement in the country.

  19. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2008-01-01

    ORDINARY MEETING ON 27 FEBRUARY 2008 The main items discussed at the meetings of the Standing Concertation Committee on 27 February 2008 included: Short-term Saved Leave Scheme The Committee noted that, by the end of February 2008, some 600 staff had enrolled in the short-term saved leave scheme: approx. 58% had signed up for 1 slice, 14% for two slices, 5% for three slices and 23% for four slices. Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme The Committee agreed to recommend the Director-General to approve Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme. Administrative Circular No. 30 (Rev. 2) - Financial benefits upon taking up appointment and termination of contract The Committee agreed to recommend the Director-General to approve Administrative Circular No. 30 (Rev. 2) - Financial Benefits upon taking up appointment and termination of contract. Progressive Retirement Programme The Progressive Retirement Programme (PR...

  20. Universal quantifier derived from AFM analysis links cellular mechanical properties and cell-surface integration forces with microbial deposition and transport behavior.

    Science.gov (United States)

    Li, Yueyun; Wang, Xin; Onnis-Hayden, Annalisa; Wan, Kai-tak; Gu, April Z

    2014-01-01

    In this study, we employed AFM analysis combined with mathematical modeling for quantifying cell-surface contact mechanics and magnitude and range of cell-surface interaction forces for seven bacterial strains with a wide range of cell morphology, dimension, and surface characteristics. Comprehensive cell-surface characterization including surface charge, extracellular polymeric substance content, hydrophobicity, and cell-cell aggregation analyses were performed. Flow-through column tests were employed to determine the attachment efficiency and deposition-transport behavior of these bacterial strains. No statistically significant correlation between attachment efficiency and any single-cell surface property was identified. Single-cell characterization by atomic force microscopy (AFM) yielded the mechanical deformation and elastic modulus, penetration resistance to AFM probe penetration by cellular surface substances (CSS), range and magnitude of the repulsive-attractive intersurface forces, and geometry of each strain. We proposed and derived a universal dimensionless modified Tabor's parameter to integrate all these properties that account for their collective behavior. Results showed that the Tabor parameter derived from AFM analysis correlated well with experimentally determined attachment efficiency (α), which therefore is able to link microscale cell-surface properties with macroscale bacterial transport behavior. Results suggested that the AFM tests performed between a single cell and a surface captured the key quantities of the interactions between the cell and the surface that dictate overall cell attachment behavior. Tabor's parameter therefore can be potentially incorporated into the microbial transport model.

  1. Self-assembly, redox activity, and charge transport of functional surface nano-architectures by molecular design

    Science.gov (United States)

    Skomski, Daniel

    inter-layer charge transport allowed electronic property characterization with the scanning tunneling microscope, demonstrating a narrowing of the film bandgap with increasing thickness which evidenced electron conjugation in the film. These results have advanced our understanding of supramolecular self-assembly at surfaces and how it can impact future technologies from organic-based materials.

  2. 78 FR 3908 - Aviation Security Advisory Committee (ASAC) Meeting

    Science.gov (United States)

    2013-01-17

    ... SECURITY Transportation Security Administration Aviation Security Advisory Committee (ASAC) Meeting AGENCY... Meeting. SUMMARY: The Transportation Security Administration (TSA) will hold a meeting of the Aviation... Administrator of TSA on matters affecting civil aviation security. This meeting is open to the public, but...

  3. The Human Dopamine Transporter: Investigating the Role of the C Terminus in Surface Targeting

    DEFF Research Database (Denmark)

    Vægter, Christian Bjerggaard

    2005-01-01

    Dopaminergic neurotransmission is involved in the modulation of locomotor activity, emotional behavior, memory and cognition. Hence, imbalances in the dopaminergic system in humans have been hypothesized to contribute to the pathogenesis of a number of illnesses, including Parkinson's disease...... also found evidence for a direct interaction between DAT and the Ca2+/calmodulin dependent kinase II α (CaMKIIα) and this interaction seems to depend on the same epitopes that are essential for surface targeting of DAT. Finally, using a fluorescently labelled cocaine analogue we were able to detect...

  4. Transport Properties of Hydrogen-Terminated Silicon Surface Controlled by Ionic-Liquid Gating

    Science.gov (United States)

    Sasama, Yosuke; Yamaguchi, Takahide; Tanaka, Masashi; Takeya, Hiroyuki; Takano, Yoshihiko

    2017-01-01

    We fabricated electric double-layer transistors on the hydrogen-terminated (111)-oriented surface of non-doped silicon using ionic liquid as a gate dielectric. We introduced hole carriers into silicon with the application of a negative gate voltage. The sheet resistance of silicon was controlled by more than three orders of magnitude at 220 K by changing the gate voltage. The temperature dependence of sheet resistance became weak as the gate voltage was increased, suggesting the approach to an insulator-metal transition.

  5. Assimilation of surface NO2 and O3 observations into the SILAM chemistry transport model

    Science.gov (United States)

    Vira, J.; Sofiev, M.

    2015-02-01

    This paper describes the assimilation of trace gas observations into the chemistry transport model SILAM (System for Integrated modeLling of Atmospheric coMposition) using the 3D-Var method. Assimilation results for the year 2012 are presented for the prominent photochemical pollutants ozone (O3) and nitrogen dioxide (NO2). Both species are covered by the AirBase observation database, which provides the observational data set used in this study. Attention was paid to the background and observation error covariance matrices, which were obtained primarily by the iterative application of a posteriori diagnostics. The diagnostics were computed separately for 2 months representing summer and winter conditions, and further disaggregated by time of day. This enabled the derivation of background and observation error covariance definitions, which included both seasonal and diurnal variation. The consistency of the obtained covariance matrices was verified using χ2 diagnostics. The analysis scores were computed for a control set of observation stations withheld from assimilation. Compared to a free-running model simulation, the correlation coefficient for daily maximum values was improved from 0.8 to 0.9 for O3 and from 0.53 to 0.63 for NO2.

  6. Predicting the Amplitude and Hemispheric Asymmetry of Solar Cycle 25 with Surface Flux Transport

    CERN Document Server

    Hathaway, David H

    2016-01-01

    Evidence strongly indicates that the strength of the Sun's polar fields near the time of a sunspot cycle minimum determines the strength of the following solar activity cycle. We use our Advective Flux Transport (AFT) code, with flows well constrained by observations, to simulate the evolution of the Sun's polar magnetic fields from early 2016 to the end of 2019 --- near the expected time of Cycle 24/25 minimum. We run a series of simulations in which the uncertain conditions (convective motion details, active region tilt, and meridional flow profile) are varied within expected ranges. We find that the average strength of the polar fields near the end of Cycle 24 will be similar to that measured near the end of Cycle 23, indicating that Cycle 25 will be similar in strength to the current cycle. In all cases the polar fields are asymmetric with fields in the south stronger than those in the north. This asymmetry would be more pronounced if not for the predicted weakening of the southern polar fields in late 20...

  7. Human papillomavirus type 16 entry: retrograde cell surface transport along actin-rich protrusions.

    Directory of Open Access Journals (Sweden)

    Mario Schelhaas

    Full Text Available The lateral mobility of individual, incoming human papillomavirus type 16 pseudoviruses (PsV bound to live HeLa cells was studied by single particle tracking using fluorescence video microscopy. The trajectories were computationally analyzed in terms of diffusion rate and mode of motion as described by the moment scaling spectrum. Four distinct modes of mobility were seen: confined movement in small zones (30-60 nm in diameter, confined movement with a slow drift, fast random motion with transient confinement, and linear, directed movement for long distances. The directed movement was most prominent on actin-rich cell protrusions such as filopodia or retraction fibres, where the rate was similar to that measured for actin retrograde flow. It was, moreover, sensitive to perturbants of actin retrograde flow such as cytochalasin D, jasplakinolide, and blebbistatin. We found that transport along actin protrusions significantly enhanced HPV-16 infection in sparse tissue culture, cells suggesting a role for in vivo infection of basal keratinocytes during wound healing.

  8. Volatile transport on inhomogeneous surfaces: II. Numerical calculations (VT3D)

    Science.gov (United States)

    Young, Leslie A.

    2017-03-01

    Several distant icy worlds have atmospheres that are in vapor-pressure equilibrium with their surface volatiles, including Pluto, Triton, and, probably, several large KBOs near perihelion. Studies of the volatile and thermal evolution of these have been limited by computational speed, especially for models that treat surfaces that vary with both latitude and longitude. In order to expedite such work, I present a new numerical model for the seasonal behavior of Pluto and Triton which (i) uses initial conditions that improve convergence, (ii) uses an expedient method for handling the transition between global and non-global atmospheres, (iii) includes local conservation of energy and global conservation of mass to partition energy between heating, conduction, and sublimation or condensation, (iv) uses time-stepping algorithms that ensure stability while allowing larger timesteps, and (v) can include longitudinal variability. This model, called VT3D, has been used in Young (2012a, 2012b), Young (2013), Olkin et al. (2015), Young and McKinnon (2013), and French et al. (2015). Many elements of VT3D can be used independently. For example, VT3D can also be used to speed up thermophysical models (Spencer et al., 1989) for bodies without volatiles. Code implementation is included in the supplemental materials and is available from the author.

  9. Transport system

    NARCIS (Netherlands)

    Drenth, K.F.

    1999-01-01

    The transport system comprises at least one road surface (2) and at least one vehicle (4) on wheels (6). The road surface (2) has a substantially bowl-shaped cross section and the vehicle (4) is designed so that the wheels (6) run directly on the road surface (2) while the road surface (2) acts as a

  10. What is greener than a VMT tax? The case for an indexed energy user fee to finance us surface transportation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, David L [ORNL

    2011-01-01

    Highway finance in the United States is perceived by many to be in a state of crisis, primarily due to the erosion of motor fuel tax revenues due to inflation, fuel economy improvement, increased use of alternative sources of energy and diversion of revenues to other purposes. Monitoring vehicle miles of travel (VMT) and charging highway users per mile has been proposed as a replacement for the motor fuel tax. A VMT user fee, however, does not encourage energy efficiency in vehicle design, purchase and operation, as would a user fee levied on all forms of commercial energy used for transportation and indexed to the average efficiency of vehicles on the road and to inflation. An indexed roadway user toll on energy (IRoUTE) would induce two to four times as much reduction in greenhouse gas (GHG) emissions and petroleum use as a pure VMT user fee. However, it is not a substitute for pricing GHG emissions and would make only a small but useful contribution to reducing petroleum dependence. An indexed energy user fee cannot adequately address the problems of traffic congestion and heavy vehicle cost responsibility. It could, however, be a key component of a comprehensive system of financing surface transportation that would eventually also include time and place specific monitoring of VMT for congestion pricing, externality charges and heavy vehicle user fees.

  11. Moving beyond the limits of mass transport in liquid absorbent microfilms through the implementation of surface-induced vortices

    Energy Technology Data Exchange (ETDEWEB)

    Bigham, S; Yu, DZ; Chugh, D; Moghaddam, S

    2014-02-01

    The slow diffusion of an absorbate molecule into an absorbent often makes the absorption process a rate-limiting step in many applications. In cases involving an absorbate with a high heat of phase change, such as water absorption into a LiBr (lithium bromide) solution, the absorption rate is further slowed due to significant heating of the absorbent. Recently, it has been demonstrated that constraining a LiBr solution film by a hydrophobic porous structure enables manipulation of the solution flow thermohydraulic characteristics. Here, it is shown that mass transport mode in a constrained laminar solution flow can be changed from diffusive to advective. This change in mode is accomplished through stretching and folding the laminar streamlines within the solution film via the implementation of micro-scale features on the flow channel surface. The process induces vortices within the solution film, which continuously bring concentrated solution from the bottom and middle of the solution channel to its interface with the vapor phase, thus leading to a significant enhancement in the absorption rate. The detailed physics of the involved transport processes is elucidated using the LBM (Lattice Boltzmann Method). Published by Elsevier Ltd.

  12. Implication of surface modified NZVI particle retention in the porous media: Assessment with the help of 1-D transport model

    Indian Academy of Sciences (India)

    Trishikhi Raychoudhury; Vikranth Kumar Surasani

    2017-06-01

    Retention of surface-modified nanoscale zero-valent iron (NZVI) particles in the porous media near the point of injection has been reported in the recent studies. Retention of excess particles in porous media can alter the media properties. The main objectives of this study are, therefore, to evaluate the effect of particle retention on the porous media properties and its implication on further NZVI particle transport under different flow conditions. To achieve the objectives, a one-dimensional transport model is developed by considering particle deposition, detachment, and straining mechanisms along with the effect of changes in porosity resulting from retention of NZVI particles. Two different flow conditions are considered for simulations. The first is a constant Darcy’s flow rate condition, which assumes a change in porosity, causes a change in pore water velocity and the second, is a constant head condition, which assumes the change in porosity, influence the permeability and hydraulic conductivity (thus Darcy’s flow rate). Overall a rapid decrease in porosity was observed as a result of high particle retention near the injection points resulting in a spatial distribution of deposition rate coefficient. In the case of constant head condition, the spatial distribution of Darcy’s velocities is predicted due to variation in porosity and hydraulic conductivity. The simulation results are compared with the data reported from the field studies; which suggests straining is likely to happen in the real field condition.

  13. Photodetection and transport properties of surface capped silicon nanowires arrays with polyacrylic acid

    Directory of Open Access Journals (Sweden)

    Kamran Rasool

    2013-08-01

    Full Text Available Efficient hybrid photodetector consisting of silicon nanowires (SiNWs (∼40 μm capped with Polyacrylic Acid (PAA is demonstrated. Highly diluted PAA with deionized (DI water was spun directly on vertical SiNW arrays prepared by metal assisted electroless chemical etching (MACE technique. We have observed ∼9, 4 and 9 times enhancement in responsivity, detectivity and external quantum efficiency in SiNWs/PAA hybrid device in comparison to SiNWs only device. Higher electrical current and photodetection may be due to the increment of hydrophilic content (acceptor like states on SiNWs interface. The higher photosensitivity can also be attributed to the presence of low refractive index PAA around SiNWs which causes funneling of photon energy into SiNWs. Surface roughness of SiNWs leads to immobilization of charge carriers and hence shows persistent photoconductivity.

  14. Optically tunable spin transport on the surface of a topological insulator

    Science.gov (United States)

    Yudin, D.; Kibis, O. V.; Shelykh, I. A.

    2016-10-01

    The emerging field of spinoptronics has a potential to supersede the functionality of modern electronics, while a proper description of strong light-matter coupling pose the most intriguing questions from both fundamental scientific and technological perspectives. In this paper we address a highly relevant issue for such a development. We theoretically explore spin dynamics on the surface of a 3D topological insulator (TI) irradiated with an off-resonant high-frequency electromagnetic wave. The strong coupling between electrons and the electromagnetic wave drastically modifies the spin properties of TI. The effects of irradiation are shown to result in anisotropy of electron energy spectrum near the Dirac point and suppression of spin current and are investigated in detail in this work.

  15. Thermoelectric transport in surface- and antimony-doped bismuth telluride nanoplates

    Science.gov (United States)

    Pettes, Michael Thompson; Kim, Jaehyun; Wu, Wei; Bustillo, Karen C.; Shi, Li

    2016-10-01

    We report the in-plane thermoelectric properties of suspended (Bi1-xSbx)2Te3 nanoplates with x ranging from 0.07 to 0.95 and thicknesses ranging from 9 to 42 nm. The results presented here reveal a trend of increasing p-type behavior with increasing antimony concentration, and a maximum Seebeck coefficient and thermoelectric figure of merit at x ˜ 0.5. We additionally tuned extrinsic doping of the surface using a tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) coating. The lattice thermal conductivity is found to be below that for undoped ultrathin Bi2Te3 nanoplates of comparable thickness and in the range of 0.2-0.7 W m-1 K-1 at room temperature.

  16. Transport mechanism of reverse surface leakage current in AlGaN/GaN high-electron mobility transistor with SiN passivation

    Institute of Scientific and Technical Information of China (English)

    郑雪峰; 张进成; 郝跃; 范爽; 陈永和; 康迪; 张建坤; 王冲; 默江辉; 李亮; 马晓华

    2015-01-01

    The transport mechanism of reverse surface leakage current in AlGaN/GaN high-electron mobility transistor (HEMT) becomes one of the most important reliability issues with the downscaling of feature size. In this paper, the research results show that the reverse surface leakage current in AlGaN/GaN HEMT with SiN passivation increases with the enhancement of temperature in a range from 298 K to 423 K. Three possible transport mechanisms are proposed and examined to explain the generation of reverse surface leakage current. By comparing the experimental data with the numerical transport models, it is found that neither Fowler–Nordheim tunneling nor Frenkel–Poole emission can describe the transport of reverse surface leakage current. However, good agreement is found between the experimental data and the two-dimensional variable range hopping (2D-VRH) model. Therefore, it is concluded that the reverse surface leakage current is dominated by the electron hopping through the surface states at barrier layer. Moreover, the activation energy of surface leakage current is extracted, which is around 0.083 eV. Finally, the SiN passivated HEMT with high Al composition and thin AlGaN barrier layer is also studied. It is observed that 2D-VRH still dominates the reverse surface leakage current and the activation energy is around 0.10 eV, which demonstrates that the alteration of AlGaN barrier layer does not affect the transport mechanism of reverse surface leakage current in this paper.

  17. The imprint of surface fluxes and transport on variations in total column carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Keppel-Aleks, G [California Institute of Technology, Pasadena; Wennberg, PO [California Institute of Technology, Pasadena; Washenfelder, RA [National Oceanic and Atmospheric Admin; Wunch, D [California Institute of Technology, Pasadena; Schneider, T [California Institute of Technology, Pasadena; Toon, GC [Jet Propulsion Laboratory, Pasadena, CA; Andres, Robert Joseph [ORNL; Blavier, J-F [Jet Propulsion Laboratory, Pasadena, CA; Connor, B [BC Consulting; Davis, K. J. [Pennsylvania State University; Desai, Desai Ankur R. [University of Wisconsin, Madison; Messerschmidt, J [University of Bremen, Bremen, Germany; Notholt, J [University of Bremen, Bremen, Germany; Roehl, CM [California Institute of Technology, Pasadena; Sherlock, V [National Institue of Water and Atmospheric Research, New Zealand; Stephens, BB [National Center for Atmospheric Research (NCAR); Vay, SA [NASA Langley Research Center; Wofsy, Steve [Harvard University

    2012-01-01

    New observations of the vertically integrated CO{sub 2} mixing ratio, , from ground-based remote sensing show that variations in are primarily determined by large-scale flux patterns. They therefore provide fundamentally different information than observations made within the boundary layer, which reflect the combined influence of large-scale and local fluxes. Observations of both and CO{sub 2} concentrations in the free troposphere show that large-scale spatial gradients induce synoptic-scale temporal variations in in the Northern Hemisphere midlatitudes through horizontal advection. Rather than obscure the signature of surface fluxes on atmospheric CO{sub 2}, these synoptic-scale variations provide useful information that can be used to reveal the meridional flux distribution. We estimate the meridional gradient in from covariations in and potential temperature, {theta}, a dynamical tracer, on synoptic timescales to evaluate surface flux estimates commonly used in carbon cycle models. We find that simulations using Carnegie Ames Stanford Approach (CASA) biospheric fluxes underestimate both the seasonal cycle amplitude throughout the Northern Hemisphere midlatitudes and the meridional gradient during the growing season. Simulations using CASA net ecosystem exchange (NEE) with increased and phase-shifted boreal fluxes better fit the observations. Our simulations suggest that climatological mean CASA fluxes underestimate boreal growing season NEE (between 45-65{sup o} N) by {approx}40%. We describe the implications for this large seasonal exchange on inference of the net Northern Hemisphere terrestrial carbon sink.

  18. Role of rainfall intensity and hydrology in nutrient transport via surface runoff.

    Science.gov (United States)

    Kleinman, Peter J A; Srinivasan, M S; Dell, Curtis J; Schmidt, John P; Sharpley, Andrew N; Bryant, Ray B

    2006-01-01

    Loss of soil nutrients in runoff accelerates eutrophication of surface waters. This study evaluated P and N in surface runoff in relation to rainfall intensity and hydrology for two soils along a single hillslope. Experiments were initiated on 1- by 2-m plots at foot-slope (6%) and mid-slope (30%) positions within an alfalfa (Medicago sativa L.)-orchardgrass (Dactylis glomerata L.) field. Rain simulations (2.9 and 7.0 cm h(-1)) were conducted under wet (spring) and dry (late-summer) conditions. Elevated, antecedent soil moisture at the foot-slope during the spring resulted in less rain required to generate runoff and greater runoff volumes, compared with runoff from the well-drained mid-slope in spring and at both landscape positions in late summer. Phosphorus in runoff was primarily in dissolved reactive form (DRP averaged 71% of total P), with DRP concentrations from the two soils corresponding with soil test P levels. Nitrogen in runoff was mainly nitrate (NO3-N averaged 77% of total N). Site hydrology, not chemistry, was primarily responsible for variations in mass N and P losses with landscape position. Larger runoff volumes from the foot-slope produced higher losses of total P (0.08 kg ha(-1)) and N (1.35 kg ha(-1)) than did runoff from the mid-slope (0.05 total P kg ha(-1); 0.48 kg N ha(-1)), particularly under wet, spring-time conditions. Nutrient losses were significantly greater under the high intensity rainfall due to larger runoff volumes. Results affirm the critical source area concept for both N and P: both nutrient availability and hydrology in combination control nutrient loss.

  19. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment.

    Science.gov (United States)

    Ellis, Laura-Jayne A; Valsami-Jones, Eugenia; Lead, Jamie R; Baalousha, Mohammed

    2016-10-15

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water - MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV-visible spectrometry (UV-vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96h (4days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Comparing Methods of Separating Bacterial Biofilms on the Surface of Water Transportation Pipes and Equipment of Milking in the Farms

    Directory of Open Access Journals (Sweden)

    setareh nabizadeh

    2016-08-01

    Full Text Available Introduction Bacterial biofilms can be both useful and harmful based on their combination and locations. Biofilm formation occurs as a stepwise process. Their formation in liquid transportation pipes used for milking system and drinking water in animal farms may create some problems and is a potential source of pollution. Speed of biofilm formation depends on many factors including: construction and functional characteristics of bacteria, the composition and culture conditions such as temperature and substratum. In this research the Bacillus subtillis bacteria with special characteristics was selected due to its capability for biofilm creation. Bacillus subtillis bacteria is mobility and a stronger connection than other bacteria levels are created. In the research conducted in the biofilm there are many resources on biofilm formation by Bacillus subtillis bacteria. Bacillus subtillis is saprophytic in the soil, water and air. There is also the ability to form spores of Bacillus subtillis. Materials and Methods Firstly the possibility of creating biofilms on different Plastic (polyvinilchlorid, polypropylene, polyethylengelycole, alluminum and glass surfaces in three temperatures of 4°C, 30°C and 37°C were studied. Two different methods of biofilms separation including separating swap and vortex were tested and their efficienceies were calculated. After biofilm formation on parts of the vortex separation method after washing parts in sterile conditions in a tube containing normal saline for 4 minutes was vortex. The bacterial suspension decreasing dilution series was created. Pour plate in medium using agar plate count agar and was cultured at 30°C for 24-48 hours. Numbers of colonies were counted. The numbers of biofilm cells were calculated. In swap method after biofilm formation on parts using a cotton swap was isolated biofilms. The swap was transferred to tube containing normal saline and the bacterial suspension decreasing dilution

  1. Mechanisms controlling surface ozone over East Asia: a multiscale study coupling regional and global chemical transport models

    Science.gov (United States)

    Lin, M.; Holloway, T.; Oki, T.; Streets, D. G.; Richter, A.

    2008-12-01

    Mechanisms controlling surface ozone (O3) over East Asia are examined using the regional Community Multiscale Air Quality (CMAQ) model at two horizontal scales: 81 km and 27 km. Through sensitivity studies and comparison with recently available satellite data and surface measurements in China and Japan, we find that the O3 budget over East Asia shows complex interactions among photochemical production, regional transport, meteorological conditions, burning of agricultural residues, and global inflows. For example, wintertime surface O3 over northern domain is sensitive to boundary conditions derived from the MOZART (Model for Ozone and Related Tracers) global model, whereas summertime O3 budget is controlled by the competitive processes between photochemical production and monsoonal intrusion of low-O3 marine air masses from tropical Pacific. We find that simulated surface O3 for 2001 does not exhibit the same sharp drop in July and August concentrations that is observed at two mountaintop sites (Tai and Hua) for 2004 and Beijing for 1995-2005. CMAQ sensitivity tests with two widely used photochemical schemes demonstrate that over the industrial areas in East Asia north of 30° N, SAPRC99 produces higher values of mean summertime O3 than CBIV, amounting to a difference of 10 ppb. In addition, analysis of NCEP winds and geopotential heights suggests that southwesterly monsoonal intrusion in central east China is weakened in August 2001 as compared with the climatologically mean for 1980-2005. Further examination of the O3 diurnal cycle at nine Japanese sites shows that boundary layer evolution has an important effect on the vertical mixing of ground-level O3, and error in near surface meteorology might contribute to overprediction of nighttime O3 in urban and rural areas. In conclusion, the uncertainties in simulating cloud activities and convection mixing, Asian monsoon circulation, photochemical production, and nighttime cooling explain why CMAQ with 81 km

  2. Mechanisms controlling surface ozone over East Asia: a multiscale study coupling regional and global chemical transport models

    Directory of Open Access Journals (Sweden)

    M. Lin

    2008-12-01

    Full Text Available Mechanisms controlling surface ozone (O3 over East Asia are examined using the regional Community Multiscale Air Quality (CMAQ model at two horizontal scales: 81 km and 27 km. Through sensitivity studies and comparison with recently available satellite data and surface measurements in China and Japan, we find that the O3 budget over East Asia shows complex interactions among photochemical production, regional transport, meteorological conditions, burning of agricultural residues, and global inflows. For example, wintertime surface O3 over northern domain is sensitive to boundary conditions derived from the MOZART (Model for Ozone and Related Tracers global model, whereas summertime O3 budget is controlled by the competitive processes between photochemical production and monsoonal intrusion of low-O3 marine air masses from tropical Pacific. We find that simulated surface O3 for 2001 does not exhibit the same sharp drop in July and August concentrations that is observed at two mountaintop sites (Tai and Hua for 2004 and Beijing for 1995–2005. CMAQ sensitivity tests with two widely used photochemical schemes demonstrate that over the industrial areas in East Asia north of 30° N, SAPRC99 produces higher values of mean summertime O3 than CBIV, amounting to a difference of 10 ppb. In addition, analysis of NCEP winds and geopotential heights suggests that southwesterly monsoonal intrusion in central east China is weakened in August 2001 as compared with the climatologically mean for 1980–2005. Further examination of the O3 diurnal cycle at nine Japanese sites shows that boundary layer evolution has an important effect on the vertical mixing of ground-level O3, and error in near surface meteorology might contribute to overprediction of nighttime O3 in urban and rural areas. In conclusion, the uncertainties in simulating cloud activities and

  3. Cell surface receptors for signal transduction and ligand transport - a design principles study

    Energy Technology Data Exchange (ETDEWEB)

    Shankaran, Harish; Resat, Haluk; Wiley, H. S.

    2007-06-01

    Although many different receptors undergo endocytosis, the system-level design principles that govern the evolution of receptor dynamics are far from fully understood. We have constructed a generalized mathematical model to understand how receptor internalization dynamics encodes receptor function and regulation. Parametric analysis of the response of receptor systems to ligand inputs reveals that receptors can be categorized a being: i) avidity-controlled where the response control depends primarily on the extracelluar 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 epidermal growth factor receptor is a dual-sensitivity receptor. Significantly, we show that ligand-induced endocytosis is a mechanism to anhance the accuracy of signaling receptors rather than 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 regulations.

  4. Surface roughness and phonon transport in thin Si nanowires: an atomistic study

    Science.gov (United States)

    Carrete, Jesus; Gallego, Luis Javier; Varela, Luis Miguel; Mingo, Natalio

    2011-03-01

    Good thermal insulation is much harder to achieve than electrical insulation. Thus, the astonishingly low thermal conductivities recently reported on Si nanowires came as a surprise, since the displayed values were an order of magnitude lower than predicted by the diffuse boundary limit of Casimir's theory. Recent theoretical work has employed the Born approximation to predict a very much enhanced boundary scattering rate that would lead to a thermal conductivity well below the Casimir limit. We present a Green's function calculation that answers the question of whether the Casimir limit to the phonon mean free path can be overcome by roughness. Our results show that the mean free path (MFP) and the thermal conductivity of a nanowire are very close to the Casimir limit for shallow disorder, and can only be pushed below it using very deep surface roughness, well beyond previous estimates. We also explore the limits of the Born approximation in this context using vacancies and isotopic impurities as defects. This work was supported by the Spanish MICINN/FEDER (FIS2008-04894/FIS) and the Xunta de Galicia (INCITE09E2R206033ES). J.Carrete thanks the Spanish Ministry of Education for a FPU grant.

  5. Cell-surface signaling in Pseudomonas: stress responses, iron transport, and pathogenicity.

    Science.gov (United States)

    Llamas, María A; Imperi, Francesco; Visca, Paolo; Lamont, Iain L

    2014-07-01

    Membrane-spanning signaling pathways enable bacteria to alter gene expression in response to extracytoplasmic stimuli. Many such pathways are cell-surface signaling (CSS) systems, which are tripartite molecular devices that allow Gram-negative bacteria to transduce an extracellular stimulus into a coordinated transcriptional response. Typically, CSS systems are composed of the following: (1) an outer membrane receptor, which senses the extracellular stimulus; (2) a cytoplasmic membrane-spanning protein involved in signal transduction from the periplasm to the cytoplasm; and (3) an extracytoplasmic function (ECF) sigma factor that initiates expression of the stimulus-responsive gene(s). Members of genus Pseudomonas provide a paradigmatic example of how CSS systems contribute to the global control of gene expression. Most CSS systems enable self-regulated uptake of iron via endogenous (pyoverdine) or exogenous (xenosiderophores, heme, and citrate) carriers. Some are also implicated in virulence, biofilm formation, and cell-cell interactions. Incorporating insights from the well-characterized alginate regulatory circuitry, this review will illustrate common themes and variations at the level of structural and functional properties of Pseudomonas CSS systems. Control of the expression and activity of ECF sigma factors are central to gene regulation via CSS, and the variety of intrinsic and extrinsic factors influencing these processes will be discussed.

  6. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2009-01-01

    Main points examined at the meeting of 24 June 2009 Results of the 2009 MARS exercise The Committee took note of the results of the 2009 MARS exercise presented by the Head of the HR Department, expressing satisfaction for the early availability of the statistics and for the fact that the analysis of the results covered the last three years. Status report on the work on the five-yearly review The Committee took note of a presentation by P. Gildemyn on the data collection procedure for the 2010 five-yearly review (staff, fellows, associate members of the personnel, CHIS) and of the proposed work schedule. Implications for employment conditions of the discussions at the Finance Committee and Council on 17 and 18 June 2009 The Chairman briefly reported on the discussions at the meetings of the Finance Committee and Council in June 2009, on the 2010-2014 medium-term plan and the 2010 preliminary draft budget, as well as on the modified strategy and goals for 2009. The Committee ...

  7. Estimating source-attributable health impacts of ambient fine particulate matter exposure: global premature mortality from surface transportation emissions in 2005

    Science.gov (United States)

    Chambliss, S. E.; Silva, R.; West, J. J.; Zeinali, M.; Minjares, R.

    2014-10-01

    Exposure to ambient fine particular matter (PM2.5) was responsible for 3.2 million premature deaths in 2010 and is among the top ten leading risk factors for early death. Surface transportation is a significant global source of PM2.5 emissions and a target for new actions. The objective of this study is to estimate the global and national health burden of ambient PM2.5 exposure attributable to surface transportation emissions. This share of health burden is called the transportation attributable fraction (TAF), and is assumed equal to the proportional decrease in modeled ambient particulate matter concentrations when surface transportation emissions are removed. National population-weighted TAFs for 190 countries are modeled for 2005 using the MOZART-4 global chemical transport model. Changes in annual average concentration of PM2.5 at 0.5 × 0.67 degree horizontal resolution are based on a global emissions inventory and removal of all surface transportation emissions. Global population-weighted average TAF was 8.5 percent or 1.75 μg m-3 in 2005. Approximately 242 000 annual premature deaths were attributable to surface transportation emissions, dominated by China, the United States, the European Union and India. This application of TAF allows future Global Burden of Disease studies to estimate the sector-specific burden of ambient PM2.5 exposure. Additional research is needed to capture intraurban variations in emissions and exposure, and to broaden the range of health effects considered, including the effects of other pollutants.

  8. Facile spray-coating process for the fabrication of tunable adhesive superhydrophobic surfaces with heterogeneous chemical compositions used for selective transportation of microdroplets with different volumes.

    Science.gov (United States)

    Li, Jian; Jing, Zhijiao; Zha, Fei; Yang, Yaoxia; Wang, Qingtao; Lei, Ziqiang

    2014-06-11

    In this paper, tunable adhesive superhydrophobic ZnO surfaces have been fabricated successfully by spraying ZnO nanoparticle (NP) suspensions onto desired substrates. We regulate the spray-coating process by changing the mass percentage of hydrophobic ZnO NPs (which were achieved by modifying hydrophilic ZnO NPs with stearic acid) in the hydrophobic/hydrophilic ZnO NP mixtures to control heterogeneous chemical composition of the ZnO surfaces. Thus, the water adhesion on the same superhydrophobic ZnO surface could be effectively tuned by controlling the surface chemical composition without altering the surface morphology. Compared with the conventional tunable adhesive superhydrophobic surfaces, on which there were only three different water sliding angle values: lower than 10°, 90° (the water droplet is firmly pinned on the surface at any tilted angles), and the value between the two ones, the water adhesion on the superhydrophobic ZnO surfaces has been tuned effectively, on which the sliding angle is controlled from 2 ± 1° to 9 ± 1°, 21 ± 2°, 39 ± 3°, and 90°. Accordingly, the adhesive force can be adjusted from extremely low (∼2.5 μN) to very high (∼111.6 μN). On the basis of the different adhesive forces of the tunable adhesive superhydrophobic surfaces, the selective transportation of microdroplets with different volumes was achieved, which has never been reported before. In addition, we demonstrated a proof of selective transportation of microdroplets with different volumes for application in the droplet-based microreactors via our tunable adhesive superhydrophobic surfaces for the quantitative detection of AgNO3 and NaOH. The results reported herein realize the selective transportation of microdroplets with different volumes and we believe that this method would potentially be used in many important applications, such as selective water droplet transportation, biomolecular quantitative detection and droplet-based biodetection.

  9. Evaluation of influence of surface barrier in solid on ion reflection by bipartition model of ion transport

    Institute of Scientific and Technical Information of China (English)

    YANG Dai-Lun; WU Zhang-Wen

    2004-01-01

    The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory has been developed instead of the MC simulation, due to important implication of the effect for fusion research. In the present paper we have calculated the number reflection coefficients of H+, D+, He and T+ normally incident on C,Al and Cu for ion energy from several eV to one hundred keV respectively. Our computational results accorded with the MC simulation. The results have shown that the effect of surface barrier on ion reflection becomes evident when the energy of incident ions is lower than one keV. In particular, for the ion energy from several eV to one hun dred eV, the discrepancies of number reflection coefficients can increase up to 0.1~0.3, showing this influence to be very important.

  10. Modeling disinfection of plastic poultry transport cages inoculated with Salmonella enteritids by slightly acidic electrolyzed water using response surface methodology.

    Science.gov (United States)

    Zang, Y T; Li, B M; Bing, Sh; Cao, W

    2015-09-01

    In order to reduce the risk of enteric pathogens transmission in animal farms, the disinfection effectiveness of slightly acidic electrolyzed water (SAEW, pH 5.85 to 6.53) for inactivating Salmonella Enteritidis on the surface of plastic poultry transport cages was evaluated. The coupled effects of the tap water cleaning time (5 to 15 s), SAEW treatment time (20 to 40 s), and available chlorine concentrations (ACCs) of 30 to 70 mg/l on the reductions of S. Enteritidis on chick cages were investigated using a central composite design of the response surface methodology (RSM). The established RS model had a goodness of fit quantified by the parameter R2 (0.971), as well as a lack of fit test (P>0.05). The maximum reduction of 3.12 log10 CFU/cm2 for S. Enteritidis was obtained for the cage treated with tap water cleaning for 15 s followed by SAEW treatment for 40 s at an ACC of 50 mg/l. Results indicate that the established RS model has shown the potential of SAEW in disinfection of bacteria on cages. © 2015 Poultry Science Association Inc.

  11. Insights into a dust event transported through Beijing in spring 2012: Morphology, chemical composition and impact on surface aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Wei [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502 (Japan); Niu, Hongya [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Key Laboratory of Resource Exploration Research of Hebei Province, Hebei University of Engineering, Handan, Hebei 056038 (China); Zhang, Daizhou [Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502 (Japan); Wu, Zhijun [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Chen, Chen [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Beijing Municipal Environmental Monitoring Center, Beijing 100044 (China); Wu, Yusheng; Shang, Dongjie [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Hu, Min, E-mail: minhu@pku.edu.cn [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China)

    2016-09-15

    Multiple approaches were used to investigate the evolution of surface aerosols in Beijing during the passage of a dust event at high altitude, which was from the Gobi areas of southern Mongolia and covered a wide range of North China. Single particle analysis with electron microscope showed that the majority of coarse particles were mineral ones, and most of them were in the size range of 1–7 μm with a peak of number concentration at about 3.5 μm. Based on elemental composition and morphology, the mineral particles could be classified into several groups, including Si-rich (71%), Ca-rich (15%), Fe-rich (6%), and halite-rich (2%), etc., and they were the main contributors to the aerosol optical depth as the dust occurred. The size distributions of surface aerosols were significantly affected by the dust intrusion. The average number concentration of accumulation mode particles during the event was about 400 cm{sup −3}, which was much lower than that in heavily polluted days (6300 cm{sup −3}). At the stage of floating dust, the number concentration of accumulation mode particles decreased, and coarse particles contributed to total volume concentration of particulate matter as much as 90%. The accumulation mode particles collected in this stage were mostly in the size range of 0.2–0.5 μm, and were rectangular or spherical. They were considered to be particles consisting of ammonium sulfate. New particle formation (NPF) was observed around noon in the three days during the dust event, indicating that the passage of the dust was probably favorable for NPF. - Highlights: • A dust event transported at high altitude through Beijing was investigated. • The dust event caused high variation in surface aerosol number concentrations. • Fine particles in the floating dust period probably consisted of ammonium sulfate. • Passage of the dust induced a favorable condition for new particle formation.

  12. Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

    Science.gov (United States)

    Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

    2014-09-01

    This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing.

  13. [Hospital clinical ethics committees].

    Science.gov (United States)

    Gómez Velásquez, Luis; Gómez Espinosa, Luis Néstor

    2007-01-01

    The scientific and technological advances have been surprising, more in the two last decades, but they don't go united with to the ethical values of the medical professional practice, it has been totally escaped, specially when the biological subsistence, the maintenance of the life through apparatuses and the mechanisms that prolong the existence are who undergoes an alteration that until recently time was mortal shortly lapse. It is common listening that exist a crisis in the medical profession, but what really is it of human values, which as soon and taken into nowadays, actually professional account, which gives rise to a dehumanization towards the life, the health, the disease, the suffering and the death. The ideal of the doctor to give to service to the man in its life and health, as well to be conscious that the last biological process that must fulfill is the death, and when it appears, does not have considered as a actually professional failure. It has protect to the patient as the extreme cruelty therapeutic, that it has right a worthy death. It's taking to the birth of the hospital ethics committees, they have like function to analyze, to advise and to think about the ethical dilemmas that appear actually clinical or in the biomedical investigation. In 1982 in the UEA only 1% of its hospitals had a ethics committees; by 1988, it was 67% and the 100% in 2000. In Mexico the process of the formation by these committees begins, only in the Military Central Hospital, to count the ethics committee on 1983, also the Hospital no. 14 of the IMSS in Guadalajara, it works with regularity from 1995, with internal teaching of bioethic. The Secretariat of Health has asked the formation of the bioethical committees in each hospital, and order the it was be coordinated by the National Committee of Bioética. The integration of these committees is indispensable that their members have the knowledge necessary of bioética. The Mexican Society of Ortopedia, conscious of

  14. Practice affairs committee

    Directory of Open Access Journals (Sweden)

    Dan Sadowski

    2004-01-01

    Full Text Available The Practice Affairs Committee has had a productive year representing the interests of gastroenterologists involved in clinical care. The principle mandate of the committee is to address all issues relevant to the practice of gastroenterology, such as participation in the development of clinical practice guidelines and education programs, and the facilitation of clinical research. A major activity in 2003 was participation in the drafting of several new clinical practice guidelines: Infliximab and the management of Crohn's disease;Screening for colorectal cancer; andManagement of gastroesophageal reflux disease.

  15. 78 FR 69991 - Advisory Committee; Veterinary Medicine Advisory Committee; Termination

    Science.gov (United States)

    2013-11-22

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 14 Advisory Committee; Veterinary Medicine... Food and Drug Administration (FDA) is announcing the termination of the Veterinary Medicine Advisory Committee. This document removes the Veterinary Advisory Committee from the Agency's list of...

  16. 75 FR 63888 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2010-10-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... regarding piracy --Matters arising from the 25th extraordinary and the 104th regular sessions of the...

  17. 76 FR 12787 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2011-03-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... piracy; --Matters arising from the 105th regular session of the IMO Council; --Technical...

  18. 77 FR 12353 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2012-02-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... Convention, 2006; Fair treatment of seafarers in the event of a maritime accident; Piracy; Matters...

  19. 78 FR 17467 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2013-03-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will conduct an... seafarers in the event of a maritime accident. --Piracy. --Collation and preservation of evidence...

  20. 77 FR 21619 - Shipping Coordinating Committee; Notice of Committee Meeting

    Science.gov (United States)

    2012-04-10

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF STATE Shipping Coordinating Committee; Notice of Committee Meeting The Shipping Coordinating Committee (SHC) will... implementation of new measures; Role of the human element; Formal safety assessment; Piracy and armed...

  1. A Comparison of Numerical Strategies for Modeling the Transport Phenomena in High-Energy Laser Surface Alloying Process

    Directory of Open Access Journals (Sweden)

    Dipankar Chatterjee

    2017-06-01

    Full Text Available A comparative assessment is done on the effectiveness of some developed and reported macroscopic and mesoscopic models deployed for addressing the three-dimensional thermo-fluidic transport during high-power laser surface alloying process. The macroscopic models include the most celebrated k–ε turbulence model and the large eddy simulation (LES model, whereas a kinetic theory-based lattice Boltzmann (LB approach is invoked under the mesoscopic paradigm. The time-dependent Navier–Stokes equations are transformed into the k–ε turbulence model by performing the Reynolds averaging technique, whereas a spatial filtering operation is used to produce the LES model. The models are suitably modified to address the turbulent melt-pool convection by using a modified eddy viscosity expression including a damping factor in the form of square root of the liquid fraction. The LB scheme utilizes three separate distribution functions to monitor the underlying hydrodynamic, thermal and compositional fields. Accordingly, the kinematic viscosity, thermal and mass diffusivities are adjusted independently. A single domain fixed-grid enthalpy-porosity approach is utilized to model the phase change phenomena in conjunction with an appropriate enthalpy updating closure scheme. The performance of these models is recorded by capturing the characteristic nature of the thermo-fluidic transport during the laser material processing. The maximum values of the pertinent parameters in the computational domain obtained from several modeling efforts are compared to assess their capabilities. The comparison shows that the prediction from the k–ε turbulence model is higher than the LES and LB models. In addition, the results from all three models are compared with the available experimental results in the form of dimensionless composition of the alloyed layer along the dimensionless depth of the pool. The comparison reveals that the LB and the LES approaches are better

  2. Surface-state-dominated transport in crystals of the topological crystalline insulator In-doped Pb1 -xSnxTe

    Science.gov (United States)

    Zhong, Ruidan; He, Xugang; Schneeloch, J. A.; Zhang, Cheng; Liu, Tiansheng; Pletikosić, I.; Yilmaz, T.; Sinkovic, B.; Li, Qiang; Ku, Wei; Valla, T.; Tranquada, J. M.; Gu, Genda

    2015-05-01

    Three-dimensional topological insulators and topological crystalline insulators represent new quantum states of matter, which are predicted to have insulating bulk states and spin-momentum-locked gapless surface states. Experimentally, it has proven difficult to achieve the high bulk resistivity that would allow surface states to dominate the transport properties over a substantial temperature range. Here we report a series of indium-doped Pb1 -xSnxTe compounds that manifest huge bulk resistivities together with evidence consistent with the topological character of the surface states for x ≳0.35 , based on thickness-dependent transport studies and magnetoresistance measurements. For these bulk-insulating materials, the surface states determine the resistivity for temperatures beyond 20 K.

  3. Connecting Surface Emissions, Convective Uplifting, and Long-Range Transport of Carbon Monoxide in the Upper Troposphere: New Observations from the Aura Microwave Limb Sounder

    Science.gov (United States)

    Jiang, Jonathan H.; Livesey, Nathaniel J.; Su, Hui; Neary, Lori; McConnell, John C.; Richards, Nigel A. D.

    2007-01-01

    Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed; in combination with the CO surface emission climatology and data from the NCEP analyses. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality.

  4. CCCT - Patient Advocate Steering Committee

    Science.gov (United States)

    The Patient Advocate Steering Committee (PASC) works to ensure advocates involved with the Scientific Steering Committees (SSCs) are completely integrated in the development, implementation, and monitoring of clinical trials within those groups.

  5. Additively manufactured metallic porous biomaterials based on minimal surfaces: A unique combination of topological, mechanical, and mass transport properties.

    Science.gov (United States)

    Bobbert, F S L; Lietaert, K; Eftekhari, A A; Pouran, B; Ahmadi, S M; Weinans, H; Zadpoor, A A

    2017-04-15

    Porous biomaterials that simultaneously mimic the topological, mechanical, and mass transport properties of bone are in great demand but are rarely found in the literature. In this study, we rationally designed and additively manufactured (AM) porous metallic biomaterials based on four different types of triply periodic minimal surfaces (TPMS) that mimic the properties of bone to an unprecedented level of multi-physics detail. Sixteen different types of porous biomaterials were rationally designed and fabricated using selective laser melting (SLM) from a titanium alloy (Ti-6Al-4V). The topology, quasi-static mechanical properties, fatigue resistance, and permeability of the developed biomaterials were then characterized. In terms of topology, the biomaterials resembled the morphological properties of trabecular bone including mean surface curvatures close to zero. The biomaterials showed a favorable but rare combination of relatively low elastic properties in the range of those observed for trabecular bone and high yield strengths exceeding those reported for cortical bone. This combination allows for simultaneously avoiding stress shielding, while providing ample mechanical support for bone tissue regeneration and osseointegration. Furthermore, as opposed to other AM porous biomaterials developed to date for which the fatigue endurance limit has been found to be ≈20% of their yield (or plateau) stress, some of the biomaterials developed in the current study show extremely high fatigue resistance with endurance limits up to 60% of their yield stress. It was also found that the permeability values measured for the developed biomaterials were in the range of values reported for trabecular bone. In summary, the developed porous metallic biomaterials based on TPMS mimic the topological, mechanical, and physical properties of trabecular bone to a great degree. These properties make them potential candidates to be applied as parts of orthopedic implants and/or as bone

  6. 76 FR 56454 - Consumer Advisory Committee Meeting

    Science.gov (United States)

    2011-09-13

    ... COMMISSION Consumer Advisory Committee Meeting AGENCY: Federal Communications Commission. ACTION: Notice. SUMMARY: The Commission announces the next meeting date and agenda of its Consumer Advisory Committee (Committee). The purpose of the Committee is to make recommendations to the Commission regarding...

  7. 75 FR 9898 - Consumer Advisory Committee

    Science.gov (United States)

    2010-03-04

    ... COMMISSION Consumer Advisory Committee AGENCY: Federal Communications Commission. ACTION: Notice. SUMMARY: The Commission announces the next meeting date and agenda of its Consumer Advisory Committee (``Committee''). The purpose of the ] Committee is to make recommendations to the Commission regarding...

  8. 75 FR 4819 - Consumer Advisory Committee

    Science.gov (United States)

    2010-01-29

    ... COMMISSION Consumer Advisory Committee AGENCY: Federal Communications Commission. ACTION: Notice. SUMMARY: The Commission announces the next meeting date and agenda of its Consumer Advisory Committee (``Committee''). The purpose of the Committee is to make recommendations to the Commission regarding...

  9. The European Mathematical Society Ethics Committee

    DEFF Research Database (Denmark)

    Jensen, Arne

    2011-01-01

    The Executive Committee of the European Mathematical Society created an Ethics Committee in the Spring of 2010.......The Executive Committee of the European Mathematical Society created an Ethics Committee in the Spring of 2010....

  10. Surface Spills at Unconventional Oil and Gas Sites: a Contaminant Transport Modeling Study for the South Platte Alluvial Aquifer

    Science.gov (United States)

    McCray, J. E.; Kanno, C.; McLaughlin, M.; Blotevogel, J.; Borch, T.

    2016-12-01

    Hydraulic fracturing has revolutionized the U.S.'s energy portfolio by making shale reservoirs productive and commercially viable. However, the public is concerned that the chemical constituents in hydraulic fracturing fluid, produced water, or natural gas itself could potentially impact groundwater. Here, we present fate and transport simulations of aqueous fluid surface spills. Surface spills are the most likely contamination pathway to occur during oil and gas production operations. We have three primary goals: 1) evaluate whether or not these spills pose risks to groundwater quality in the South Platte aquifer system, 2) develop a screening level methodology that could be applied at other sites and for various pollutants, and 3) demonstrate the potential importance of co-contaminant interactions using selected chemicals. We considered two types of fluid that can be accidentally released at oil and gas sites: produced water and hydraulic fracturing fluid. Benzene was taken to be a representative contaminant of interest for produced water. Glutaraldehyde, polyethylene glycol, and polyacrylamide were the chemical additives considered for spills of hydraulic fracturing fluid. We focused on the South Platte Alluvial Aquifer, which is located in the greater Denver metro area and overlaps a zone of high-density oil and gas development. Risk of groundwater pollution was based on predicted concentration at the groundwater table. In general, results showed groundwater contamination due to produced water and hydraulic fracturing fluid spills is low in most areas of the South Platte system for the contaminants and spill conditions investigated. Substantial risk may exist in certain areas where the groundwater table is shallow (less than 10 ft below ground surface) and when large spills and large post-spill storms occur. Co-chemical interactions are an important consideration in certain cases when modeling hydraulic fracturing fluid spills. By helping to identify locations

  11. Coupled Vadose Zone and Atmospheric Surface-Layer Transport of CO2 from Geologic Carbon Sequestration Sites

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, Curtis M.; Unger, Andre J.A.

    2004-03-29

    Geologic carbon dioxide (CO{sub 2}) sequestration is being considered as a way to offset fossil-fuel-related CO{sub 2} emissions to reduce the rate of increase of atmospheric CO{sub 2} concentrations. The accumulation of vast quantities of injected carbon dioxide (CO{sub 2}) in geologic sequestration sites may entail health and environmental risks from potential leakage and seepage of CO{sub 2} into the near-surface environment. We are developing and applying a coupled subsurface and atmospheric surface-layer modeling capability built within the framework of the integral finite difference reservoir simulator TOUGH2. The overall purpose of modeling studies is to predict CO{sub 2} concentration distributions under a variety of seepage scenarios and geologic, hydrologic, and atmospheric conditions. These concentration distributions will provide the basis for determining above-ground and near-surface instrumentation needs for carbon sequestration monitoring and verification, as well as for assessing health, safety, and environmental risks. A key feature of CO{sub 2} is its large density ({rho} = 1.8 kg m{sup -3}) relative to air ({rho} = 1.2 kg m{sup -3}), a property that may allow small leaks to cause concentrations in air above the occupational exposure limit of 4 percent in low-lying and enclosed areas such as valleys and basements where dilution rates are low. The approach we take to coupled modeling involves development of T2CA, a TOUGH2 module for modeling the multicomponent transport of water, brine, CO{sub 2}, gas tracer, and air in the subsurface. For the atmospheric surface-layer advection and dispersion, we use a logarithmic vertical velocity profile to specify constant time-averaged ambient winds, and atmospheric dispersion approaches to model mixing due to eddies and turbulence. Initial simulations with the coupled model suggest that atmospheric dispersion quickly dilutes diffuse CO{sub 2} seepage fluxes to negligible concentrations, and that rainfall

  12. SENIOR STAFF ADVANCEMENT COMMITTEE (SSAC)

    CERN Document Server

    2000-01-01

    Composition and mandateThe Senior Staff Advancement Committee is composed of members nominated ad persona by the Director-General.The Committee examines proposals from Divisions concerning promotions to grade 13 in Career Path IX, changes of career path to Career Path IX and advancements to the exceptional grade in Career path VIII.The Director-General may consult the Committee on any matter related to senior staff careers.The Committee makes its recommendations to the Director-General.

  13. Citizens Advisory Committees.

    Science.gov (United States)

    Stemnock, Suzanne K.

    1968-01-01

    This document contains the results of a national survey designed to determine the composition and location of permanent citizens advisory committees operating within the nation's school districts. The 52 district-wide, continuing citizens advisory bodies identified by 290 responding school systems are listed alphabetically by State. The following…

  14. Module utilization committee

    Science.gov (United States)

    Volkmer, K.; Praver, G.

    1984-01-01

    Photovoltaic collector modules were declared surplus to the needs of the U.S. Dept. of Energy. The Module Utilization Committee was formed to make appropriate disposition of the surplus modules on a national basis and to act as a broker for requests for these modules originating outside of the National Photovoltaics Program.

  15. Quantum Transport and Nano Angle-resolved Photoemission Spectroscopy on the Topological Surface States of Single Sb2Te3 Nanowires

    Science.gov (United States)

    Arango, Yulieth C.; Huang, Liubing; Chen, Chaoyu; Avila, Jose; Asensio, Maria C.; Grützmacher, Detlev; Lüth, Hans; Lu, Jia Grace; Schäpers, Thomas

    2016-09-01

    We report on low-temperature transport and electronic band structure of p-type Sb2Te3 nanowires, grown by chemical vapor deposition. Magnetoresistance measurements unravel quantum interference phenomena, which depend on the cross-sectional dimensions of the nanowires. The observation of periodic Aharonov-Bohm-type oscillations is attributed to transport in topologically protected surface states in the Sb2Te3 nanowires. The study of universal conductance fluctuations demonstrates coherent transport along the Aharonov-Bohm paths encircling the rectangular cross-section of the nanowires. We use nanoscale angle-resolved photoemission spectroscopy on single nanowires (nano-ARPES) to provide direct experimental evidence on the nontrivial topological character of those surface states. The compiled study of the bandstructure and the magnetotransport response unambiguosly points out the presence of topologically protected surface states in the nanowires and their substantial contribution to the quantum transport effects, as well as the hole doping and Fermi velocity among other key issues. The results are consistent with the theoretical description of quantum transport in intrinsically doped quasi-one-dimensional topological insulator nanowires.

  16. Conceptual and numerical modelling of radionuclide transport in near-surface systems at Forsmark. SR-Site Biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pique, Angels; Grandia, Fidel; Sena, Clara; Arcos, David; Molinero, Jorge; Duro, Lara; Bruno, Jordi (Amphos21 Consulting S.L., Barcelona (Spain))

    2010-11-15

    In the framework of the SR-Site safety assessment, a conceptual and numerical modelling of radionuclide reactive transport in near-surface systems (including till and clay systems) at Forsmark has been carried out. The objective was to evaluate the retention capacity of the near-surface systems, composed of Quaternary deposits, which would be the last natural barrier for an eventual radionuclide release from the deep repository prior to reaching the biosphere. The studied radionuclides are 14C, 129I, 36Cl, 94Nb, 59Ni, 93Mo, 79Se, 99Tc, 230Th, 90Sr, 226Ra, 135Cs and U. Conceptual description and numerical simulations of radionuclide reactive transport show that cation exchange and surface complexation on illite are active processes for the retention of several radionuclides (U, Th, Ni, Cs, Sr, Ra). Surface complexation on iron hydroxide is an active process in the till system, able to effectively retain U and Ni. Another retention process of importance is the incorporation of the radionuclides into mineral phases, either by the precipitation of pure phases or solid solutions. Quantitative modelling has been useful to illustrate the incorporation of C and Sr in the carbonate solid solution in the considered model domains (till and clay), as well as the precipitation of uraninite in the clay sediments and the precipitation of native selenium and radiobarite in the till. Other mineral phases that could, a priori, retain U, Se, Nb and Tc do not precipitate in the simulations, either due to the pH-Eh conditions and/or because the dissolved concentration of the element is not high enough under the considered simulation conditions. It is important to keep in mind that changes in these parameters and in the boundary conditions could modify the predicted behaviour of these elements. The radionuclides that are most significantly retarded are Th, Ni and Cs, mainly through sorption onto illite. Therefore, if the amount of illite (or available sorption sites) decreases, the

  17. Module Utilization Committee. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-03-01

    Photovoltaic collector modules were declared surplus to the needs of the US Department of Energy. The Module Utilization Committee was formed to make appropriate disposition of the surplus modules. The final report of that committee accounts for that disposition. The membership and activities of the committee are set forth and the results of its activities are reported.

  18. Scholarship Committees--Their Duties

    Science.gov (United States)

    Fletcher, Oscar J.

    1978-01-01

    Some functions for members of a scholarship committee are presented along with a suggested technique for committee operation and examples of problems handled by members of such a committee at the College of Veterinary Medicine at the University of Georgia. (LBH)

  19. Akt-mediated regulation of antidepressant-sensitive serotonin transporter function, cell-surface expression and phosphorylation.

    Science.gov (United States)

    Rajamanickam, Jeyaganesh; Annamalai, Balasubramaniam; Rahbek-Clemmensen, Troels; Sundaramurthy, Santhanalakshmi; Gether, Ulrik; Jayanthi, Lankupalle D; Ramamoorthy, Sammanda

    2015-05-15

    The serotonin [5-HT (5-hydroxytryptamine)] transporter (SERT) controls serotonergic neurotransmission in the brain by rapid clearance of 5-HT from the synaptic cleft into presynaptic neurons. SERTs are primary targets for antidepressants for therapeutic intervention of mood disorders. Our previous studies have identified the involvement of several signalling pathways and protein kinases in regulating SERT function, trafficking and phosphorylation. However, whether Akt/PKB (protein kinase) regulates SERT function is not known. In the present study, we made the novel observation that inhibition of Akt resulted in the down-regulation of SERT function through the regulation of SERT trafficking and phosphorylation. Akt inhibitor Akt X {10-(4'-[N-diethylamino)butyl]-2-chlorophenoxazine} reduced the endogenously phosphorylated Akt and significantly decreased 5-HT uptake and 5-HT-uptake capacity. Furthermore, SERT activity is also reduced by siRNA down-regulation of total and phospho-Akt levels. The reduction in SERT activity is paralleled by lower levels of cell-surface SERT protein, reduced SERT exocytosis with no effect on SERT endocytosis and accumulation of SERT in intracellular endocytic compartments with the most prominent localization to late endosomes and lysosomes. Akt2 inhibitor was more effective than Akt1 inhibitor in inhibiting SERT activity. Inhibition of downstream Akt kinase GSK3α/β (glycogen synthase kinase α/β) stimulates SERT function. Akt inhibition leads to a decrease in SERT basal phosphorylation. Our results provide evidence that Akt regulates SERT function and cell-surface expression by regulating the intracellular SERT distribution and plasma membrane availability, which perhaps may be linked to SERT phosphorylation state. Thus any changes in the activation of Akt and/or GSK3α/β could alter SERT-mediated 5-HT clearance and subsequently serotonergic neurotransmission.

  20. Long-range atmospheric transport of persistent organic pollutants, I: description of surface-atmosphere exchange modules and implementation in EUROS.

    NARCIS (Netherlands)

    Jacobs, C.M.J.; Pul, van W.A.J.

    1996-01-01

    Concerns a description of a model for the exchange of gaseous Persistent Organic Pollutants (POP) at land and sea surfaces and its application in the Eulerian air pollution transport model EUROS. Sample simulations of the net deposition of lindane over Europe are discussed. For non-emission areas

  1. Current status, research needs, and opportunities in applications of surface processing to transportation and utilities technologies. Proceedings of a December 1991 workshop

    Energy Technology Data Exchange (ETDEWEB)

    Czanderna, A.W.; Landgrebe, A.R. [eds.

    1992-09-01

    Goal of surface processing is to develop innovative methods of surface modification and characterization for optimum performance and environmental protection for cost-effective operational lifetimes of systems, materials, and components used in transportation and utilities. These proceedings document the principal discussions and conclusions reached at the workshop; they document chapters about the current status of surface characterization with focus on composition, structure, bonding, and atomic-scale topography of surfaces. Also documented are chapters on the current status of surface modification techniques: electrochemical, plasma-aided, reactive and nonreactive physical vapor deposition, sol-gel coatings, high-energy ion implantation, ion-assisted deposition, organized molecular assemblies, solar energy. Brief chapters in the appendices document basic research in surface science by NSF, Air Force, and DOE. Participants at the workshop were invited to serve on 10 working groups. Separate abstracts were prepared for the data base where appropriate.

  2. Studies on the selective Am3+ transport, irradiation stability and surface morphology of polymer inclusion membranes containing Cyanex-301 as carrier extractant.

    Science.gov (United States)

    Bhattacharyya, A; Mohapatra, P K; Hassan, P A; Manchanda, V K

    2011-08-15

    Transport behaviour of Am(3+) across cellulose triacetate (CTA) based polymer inclusion membranes (PIM) containing Cyanex-301 (bis(2,4,4-trimethylpentyl)dithiophosphinic acid) as the carrier extractant and tri-n-butyl phosphate (TBP) or 2-nitrophenyloctylether (NPOE) as the plasticizer was investigated from different feed and strip conditions. The TBP plasticized membrane resulted back transport of Am when alpha-hydroxy iso-butyric acid was used as the complexing agent in the strip phase while no such effect was seen when ethylene diamine tetraacetic acid (EDTA) was used as the complexant. Effect of varying Cyanex-301 concentration and bipyridyl (bipy) concentration on Am transport was also investigated. Long term reusability of the membrane was studied by measuring the permeability coefficient (P) after exposing the PIMs to a maximum gamma ray dose of ∼ 200 kGy. The surface morphology of the membranes was analyzed by atomic force microscopy and the roughness parameter was correlated to transport efficiency.

  3. Simulation of large particle transport near the surface under stable conditions: comparison with the Hanford tracer experiments

    Science.gov (United States)

    Kim, Eugene; Larson, Timothy

    A plume model is presented describing the downwind transport of large particles (1-100 μm) under stable conditions. The model includes both vertical variations in wind speed and turbulence intensity as well as an algorithm for particle deposition at the surface. Model predictions compare favorably with the Hanford single and dual tracer experiments of crosswind integrated concentration (for particles: relative bias=-0.02 and 0.16, normalized mean square error=0.61 and 0.14, for the single and dual tracer experiments, respectively), whereas the US EPA's fugitive dust model consistently overestimates the observed concentrations at downwind distances beyond several hundred meters (for particles: relative bias=0.31 and 2.26, mean square error=0.42 and 1.71, respectively). For either plume model, the measured ratio of particle to gas concentration is consistently overestimated when using the deposition velocity algorithm of Sehmel and Hodgson (1978. DOE Report PNL-SA-6721, Pacific Northwest Laboratories, Richland, WA). In contrast, these same ratios are predicted with relatively little bias when using the algorithm of Kim et al. (2000. Atmospheric Environment 34 (15), 2387-2397).

  4. Surface Transportation: Watercraft

    Science.gov (United States)

    2007-11-02

    Cardiopulmonary resuscitation (CPR). (3) Ensuring the recommended surgical equipment, instruments , and supplies are maintained on board. (4) Remaining...diseases. (6) Remaining familiar with DH MEDICO (Medical advice by radio) procedures. Familiar with emergency station bill procedures. b. Must be...AR 215–1 Morale, Welfare, and Recreation Activities and Nonappropriated Fund Instrumentalities . AR 385–10 The Army Safety Program. AR 500–60 Disaster

  5. Coupling of Insulin Secretion and Display of a Granule-resident Zinc Transporter ZnT8 on the Surface of Pancreatic Beta Cells.

    Science.gov (United States)

    Huang, Qiong; Merriman, Chengfeng; Zhang, Hao; Fu, Dax

    2017-03-10

    The islet-specific zinc transporter ZnT8 mediates zinc enrichment in the insulin secretory granules of the pancreatic beta cell. This granular zinc transporter is also a major self-antigen found in type 1 diabetes patients. It is not clear whether ZnT8 can be displayed on the cell surface and how insulin secretion may regulate the level of ZnT8 exposure to extracellular immune surveillance. Here we report specific antibody binding to the extracellular surface of rat insulinoma INS-1E cells that stably expressed a tagged human zinc transporter ZnT8. Flow cytometry analysis after fluorescent antibody labeling revealed strong correlations among the levels of ZnT8 expression, its display on the cell surface, and glucose-stimulated insulin secretion (GSIS). Glucose stimulation increased the surface display of endogenous ZnT8 from a basal level to 32.5% of the housekeeping Na(+)/K(+) ATPase on the cell surface, thereby providing direct evidence for a GSIS-dependent surface exposure of the ZnT8 self-antigen. Moreover, the variation in tagged-ZnT8 expression and surface labeling enabled sorting of heterogeneous beta cells to subpopulations that exhibited marked differences in GSIS with parallel changes in endogenous ZnT8 expression. The abundant surface display of endogenous ZnT8 and its coupling to GSIS demonstrated the potential of ZnT8 as a surface biomarker for tracking and isolating functional beta cells in mixed cell populations.

  6. Optimal estimation of the surface fluxes of methyl chloride using a 3-D global chemical transport model

    Directory of Open Access Journals (Sweden)

    X. Xiao

    2010-06-01

    Full Text Available Methyl chloride (CH3Cl is a chlorine-containing trace gas in the atmosphere contributing significantly to stratospheric ozone depletion. Large uncertainties in estimates of its source and sink magnitudes and temporal and spatial variations currently exist. GEIA inventories and other bottom-up emission estimates are used to construct a priori maps of the surface fluxes of CH3Cl. The Model of Atmospheric Transport and Chemistry (MATCH, driven by NCEP interannually varying meteorological data, is then used to simulate CH3Cl mole fractions and quantify the time series of sensitivities of the mole fractions at each measurement site to the surface fluxes of various regional and global sources and sinks. We then implement the Kalman filter (with the unit pulse response method to estimate the surface fluxes on regional/global scales with monthly resolution from January 2000 to December 2004. High frequency observations from the AGAGE, SOGE, NIES, and NOAA/ESRL HATS in situ networks and low frequency observations from the NOAA/ESRL HATS flask network are used to constrain the source and sink magnitudes. The inversion results indicate global total emissions around 4100 ± 470 Gg yr−1 with very large emissions of 2200 ± 390 Gg yr−1 from tropical plants, which turn out to be the largest single source in the CH3Cl budget. Relative to their a priori annual estimates, the inversion increases global annual fungal and tropical emissions, and reduces the global oceanic source. The inversion implies greater seasonal and interannual oscillations of the natural sources and sink of CH3Cl compared to the a priori. The inversion also reflects the strong effects of the 2002/2003 globally widespread heat waves and droughts on global emissions from tropical plants, biomass burning and salt marshes, and on the soil sink.

  7. Optimal estimation of the surface fluxes of methyl chloride using a 3-D global chemical transport model

    Directory of Open Access Journals (Sweden)

    X. Xiao

    2009-12-01

    Full Text Available Methyl chloride (CH3Cl is a chlorine-containing trace gas in the atmosphere contributing significantly to stratospheric ozone depletion. Large uncertainties in estimates of its source and sink magnitudes and temporal and spatial variations currently exist. GEIA inventories and other bottom-up emission estimates are used to construct a priori maps of the surface fluxes of CH3Cl. The Model of Atmospheric Transport and Chemistry (MATCH, driven by NCEP interannually varying meteorological data, is then used to simulate CH3Cl mole fractions and quantify the time series of sensitivities of the mole fractions at each measurement site to the surface fluxes of various regional and global sources and sinks. We then implement the Kalman filter (with the unit pulse response method to estimate the surface fluxes on regional/global scales with monthly resolution from January 2000 to December 2004. High frequency observations from the AGAGE, SOGE, NIES, and NOAA/ESRL HATS in situ networks and low frequency observations from the NOAA/ESRL HATS flask network are used to constrain the source and sink magnitudes. The inversion results indicate global total emissions around 4100±470 Gg yr−1 with very large emissions of 2200±390 Gg yr−1 from tropical plants, which turn out to be the largest single source in the CH3Cl budget. Relative to their a priori annual estimates, the inversion increases global annual fungal and tropical emissions, and reduces the global oceanic source. The inversion implies greater seasonal and interannual oscillations of the natural sources and sink of CH3Cl compared to the a priori. The inversion also reflects the strong effects of the 2002/2003 globally widespread heat waves and droughts on global emissions from tropical plants, biomass burning and salt marshes, and on the soil sink.

  8. Standing Concertation Committee - Ordinary Meeting on 3 September 2008

    CERN Multimedia

    HR Department

    2008-01-01

    The main items discussed at the meeting of the Standing Concertation Committee on 3 September 2008 included: Education fees: Indexation of the amounts for accommodation and meals The Committee approved the indexation calculations for accommodation and meals for the academic year 2008-2009. With the indexation of the lump sum payments, accommodation costs for the academic year 2007-2008 will be reimbursed at 529 CHF per month (previously CHF 500). Meals will be reimbursed at 17.50 CHF per meal (unchanged). The ceiling for school transport has been increased from 600 CHF to 622 CHF. Administrative Circular No. 26 (Rev. 8) The Committee took note of the modifications to Administrative Circular No. 26 (Rev. 8) ‘Recognition of merit of staff members’, concerning provision for the award of exceptional advancement outside the annual advancement exercise to recognize, for example, the completion of a major project. HR Survey The Committee took note of the Head of HR Department...

  9. 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.

  10. Molecular Dynamics Simulation for Surface and Transport Properties of Fluorinated Silica Nanoparticles in Water or Decane: Application to Gas Recovery Enhancement

    Directory of Open Access Journals (Sweden)

    Sepehrinia Kazem

    2017-05-01

    Full Text Available Determination of surface and transport properties of nanoparticles (NPs is essential for a variety of applications in enhanced oil and gas recoveries. In this paper, the impact of the surface chemistry of silica NPs on their hydro- and oleo-phobic properties as well as their transport properties are investigated in water or decane using molecular dynamics simulation. Trifluoromethyl or pentafluoroethyl groups as water and oil repellents are placed on the NPs. It is found that the density and residence time of liquid molecules around the NPs are modulated considerably with the existence of the functional groups on the NPs’ surfaces. Also, much larger density fluctuations for liquids close to the surface of the NPs are observed when the number of the groups on the NPs increases, indicating increased hydrophobicity. In addition, the diffusion coefficient of the NPs in either water or decane increases with increasing the number or length of the fluorocarbon chains, demonstrating non-Brownian behavior for the NPs. The surface chemistry imparts a considerable contribution on the diffusion coefficient of the NPs. Finally, potential of mean force calculations are undertaken. It is observed that the free energy of adsorption of the NPs on a mineral surface is more favorable than that of the aggregation of the NPs, which suggests the NPs adsorb preferably on the mineral surface.

  11. Committees and sponsors

    Science.gov (United States)

    2011-10-01

    International Advisory Committee Richard F CastenYale, USA Luiz Carlos ChamonSão Paulo, Brazil Osvaldo CivitareseLa Plata, Argentina Jozsef CsehATOMKI, Hungary Jerry P DraayerLSU, USA Alfredo Galindo-UribarriORNL & UT, USA James J KolataNotre Dame, USA Jorge López UTEP, USA Joseph B NatowitzTexas A & M, USA Ma Esther Ortiz IF-UNAM Stuart PittelDelaware, USA Andrés SandovalIF-UNAM Adam SzczepaniakIndiana, USA Piet Van IsackerGANIL, France Michael WiescherNotre Dame, USA Organizing Committee Libertad Barrón-Palos (Chair)IF-UNAM Roelof BijkerICN-UNAM Ruben FossionICN-UNAM David LizcanoININ Sponsors Instituto de Ciencias Nucleares, UNAMInstituto de Física, UNAMInstituto Nacional de Investigaciones NuclearesDivisión de Física Nuclear de la SMFCentro Latinoamericano de Física

  12. Standing Concertation Committee

    CERN Document Server

    HR Department

    2009-01-01

    Ordinary Meeting on 11 May 2009 The meeting of the Standing Concertation Committee held on 11 May 2009 was entirely dedicated to the preparation of the TREF meeting on 19 & 20 May 2009. The Committee took note, discussed and agreed on some clarifications on a number of documents and presentations that the Management planned to submit and/or present to TREF on the following subjects: • Personnel statistics 2008: J. Purvis presented the Personnel Statistics for 2008 prepared by HR Department. In line with the previous year, key messages were firstly, a general reduction in staff (2544 to 2400, - 6%), secondly, a reduction in administrative services personnel (from 422 to 387, - 8%) and thirdly, a marked increase in the number of Users and Unpaid Associates (from 8369 to 9140, + 9%) • Five-Yearly Review 2010: A series of draft documents were submitted for discussion, comprising an introductory document explaining the statutory basis for the following four document...

  13. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2009-01-01

    The main items discussed at the meetings of the Standing Concertation Committee in the first quarter of 2009 included: Merit Appraisal and Recognition Scheme (MARS) 2009 exercise The committee took note of 2009 MARS ceiling guidelines giving the advancement budget by career path and amounting to approx 1.80% of the basic salary bill. To this will be added 250 steps CERN-wide, financed by savings from implementation of the international indemnity for 2007, 2008 and the first half of 2009. The specific Senior Staff Guidelines, including the proposed number of promotions from Career Path E to F, were also noted. The guidelines with respect to step distribution were also noted: the minima and maxima remain the same as in previous years. Compliance with the guidelines will continue to be monitored closely (more details, including a frequently asked questions section). It was also noted that Financial Awards (awards for extraordinary service and responsibility allowances) may b...

  14. 78 FR 16757 - Twentieth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2013-03-18

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held April 4, 2013 from...

  15. 78 FR 43963 - Twenty-Third Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2013-07-22

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held on June 20,...

  16. 77 FR 71474 - Seventeenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2012-11-30

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held December 13,...

  17. 78 FR 51810 - Twenty-Fourth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2013-08-21

    ... Security Access Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control... RTCA Special Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held...

  18. 78 FR 22025 - Twenty First Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2013-04-12

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held April 9-10,...

  19. 77 FR 55894 - Fifteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Science.gov (United States)

    2012-09-11

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems DATES: The meeting will be held September 27-28,...

  20. 77 FR 25525 - Thirteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems.

    Science.gov (United States)

    2012-04-30

    ... Access Control Systems. AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems... Committee 224, Airport Security Access Control Systems DATES: The meeting will be held May 30, 2012, from...