WorldWideScience

Sample records for neutral gas transport

  1. Neutral gas transport modeling with DEGAS 2

    International Nuclear Information System (INIS)

    Karney, C.; Stotler, D.

    1993-01-01

    The authors are currently re-writing the neutral gas transport code, DEGAS, with a view to making it both faster and easier to include new physics. They present model calculations including ionization and charge exchange illustrating the way that reactions are included into DEGAS 2 and its operation on a distributed network of workstations

  2. Plasma/neutral gas transport in divertors and limiters

    International Nuclear Information System (INIS)

    Gierszewski, P.J.

    1983-09-01

    The engineering design of the divertor and first wall region of fusion reactors requires accurate knowledge of the energies and particle fluxes striking these surfaces. Simple calculations indicate that approx. 10 MW/m 2 heat fluxes and approx. 1 cm/yr erosion rates are possible, but there remain fundamental physics questions that bear directly on the engineering design. The purpose of this study was to treat hydrogen plasma and neutral gas transport in divertors and pumped limiters in sufficient detail to answer some of the questions as to the actual conditions that will be expected in fusion reactors. This was accomplished in four parts: (1) a review of relevant atomic processes to establish the dominant interactions and their data base; (2) a steady-state coupled O-D model of the plasma core, scrape-off layer and divertor exhaust to determine gross modes of operation and edge conditions; (3) a 1-D kinetic transport model to investigate the case of collisionless divertor exhaust, including non-Maxwellian ions and neutral atoms, highly collisional electrons, and a self-consistent electric field; and (4) a 3-D Monte Carlo treatment of neutral transport to correctly account for geometric effects

  3. Integral Transport Analysis Results for Ions Flowing Through Neutral Gas

    Science.gov (United States)

    Emmert, Gilbert; Santarius, John

    2017-10-01

    Results of a computational model for the flow of energetic ions and neutrals through a background neutral gas will be presented. The method models reactions as creating a new source of ions or neutrals if the energy or charge state of the resulting particle is changed. For a given source boundary condition, the creation and annihilation of the various species is formulated as a 1-D Volterra integral equation that can quickly be solved numerically by finite differences. The present work focuses on multiple-pass, 1-D ion flow through neutral gas and a nearly transparent, concentric anode and cathode pair in spherical, cylindrical, or linear geometry. This has been implemented as a computer code for atomic (3He, 3He +, 3He + +) and molecular (D, D2, D-, D +, D2 +, D3 +) ion and neutral species, and applied to modeling inertial-electrostatic connement (IEC) devices. The code yields detailed energy spectra of the various ions and energetic neutral species. Calculations for several University of Wisconsin IEC and ion implantation devices will be presented. Research supported by US Dept. of Homeland Security Grant 2015-DN-077-ARI095, Dept. of Energy Grant DE-FG02-04ER54745, and the Grainger Foundation.

  4. Understanding of Neutral Gas Transport in the Alcator C-Mod Tokamak Divertor

    International Nuclear Information System (INIS)

    Stotler, D.P.; Pitcher, C.S.; Boswell, C.J.; LaBombard, B.; Terry, J.L.; Elder, J.D.; Lisgo, S.

    2002-01-01

    A series of experiments on the effect of divertor baffling on the Alcator C-Mod tokamak provides stringent tests on models of neutral gas transport in and around the divertor region. One attractive feature of these experiments is that a trial description of the background plasma can be constructed from experimental measurements using a simple model, allowing the neutral gas transport to be studied with a stand-alone code. The neutral-ion and neutral-neutral elastic scattering processes recently added to the DEGAS 2 Monte Carlo neutral transport code permit the neutral gas flow rates between the divertor and main chamber to be simulated more realistically than before. Nonetheless, the simulated neutral pressures are too low and the deuterium Balmer-alpha emission profiles differ qualitatively from those measured, indicating an incomplete understanding of the physical processes involved in the experiment. Some potential explanations are examined and opportunities for future exploration a re highlighted. Improvements to atomic and surface physics data and models will play a role in the latter

  5. Neutral gas transport and particle recycling in the W VII-AS stellarator

    International Nuclear Information System (INIS)

    Sardei, F.; Ringler, H.; Dodhy, A.; Kuehner, G.

    1990-01-01

    Neutral gas transport simulations with the 3D DEGAS code were applied to model plasmas before the W VII-AS operation was started. For a source of neutrals due to limiter recycling the calculated neutral density distribution is strongly affected by the asymmetries of the magnetic flux surfaces, limiter and wall structures. For a typical ECF heated deuterium discharge from the first months of W VII-AS operation the time histories of H α signals at five toroidal positions provide information about the neutral fluxes due to limiter and wall recycling and to gas puffing. The H α signals are used to scale the calculated 3D distributions of the neutrals and the radial profiles of the ion sources as obtained from the DEGAS code. By comparing the results for the three different neutral sources the limiter is found to provide more than 80% of the plasma refuelling, with a recycling coefficient of about 95%. The calculated total particle fluxes resulting from the integrated ion sources are consistent with neoclassical predictions in the temperature gradient region. Near the plasma edge, however, the fluxes are strongly anomalous. The diffusion coefficient estimated from the fluxes and the measured density gradients (with z eff approx. 3) is about 1/10 - 1/20 of the electron heat conductivity. (author). 6 refs, 10 figs

  6. Three-Dimensional Neutral Transport Simulations of Gas Puff Imaging Experiments

    International Nuclear Information System (INIS)

    Stotler, D.P.; DIppolito, D.A.; LeBlanc, B.; Maqueda, R.J.; Myra, J.R.; Sabbagh, S.A.; Zweben, S.J.

    2003-01-01

    Gas Puff Imaging (GPI) experiments are designed to isolate the structure of plasma turbulence in the plane perpendicular to the magnetic field. Three-dimensional aspects of this diagnostic technique as used on the National Spherical Torus eXperiment (NSTX) are examined via Monte Carlo neutral transport simulations. The radial width of the simulated GPI images are in rough agreement with observations. However, the simulated emission clouds are angled approximately 15 degrees with respect to the experimental images. The simulations indicate that the finite extent of the gas puff along the viewing direction does not significantly degrade the radial resolution of the diagnostic. These simulations also yield effective neutral density data that can be used in an approximate attempt to infer two-dimensional electron density and temperature profiles from the experimental images

  7. Neutral Transport Simulations of Gas Puff Imaging Experiments on Alcator C-Mod

    International Nuclear Information System (INIS)

    Stotler, D.P.; LaBombard, B.; Terry, J.L.; Zweben, S.J.

    2002-01-01

    Visible imaging of gas puffs has been used on the Alcator C-Mod tokamak to characterize edge plasma turbulence, yielding data that can be compared with plasma turbulence codes. Simulations of these experiments with the DEGAS 2 Monte Carlo neutral transport code have been carried out to explore the relationship between the plasma fluctuations and the observed light emission. By imposing two-dimensional modulations on the measured time-average plasma density and temperature profiles, we demonstrate that the spatial structure of the emission cloud reflects that of the underlying turbulence. However, the photon emission rate depends on the plasma density and temperature in a complicated way, and no simple scheme for inferring the plasma parameters directly from the light emission patterns is apparent. The simulations indicate that excited atoms generated by molecular dissociation are a significant source of photons, further complicating interpretation of the gas puff imaging results.Visibl e imaging of gas puffs has been used on the Alcator C-Mod tokamak to characterize edge plasma turbulence, yielding data that can be compared with plasma turbulence codes. Simulations of these experiments with the DEGAS 2 Monte Carlo neutral transport code have been carried out to explore the relationship between the plasma fluctuations and the observed light emission. By imposing two-dimensional modulations on the measured time-average plasma density and temperature profiles, we demonstrate that the spatial structure of the emission cloud reflects that of the underlying turbulence. However, the photon emission rate depends on the plasma density and temperature in a complicated way, and no simple scheme for inferring the plasma parameters directly from the light emission patterns is apparent. The simulations indicate that excited atoms generated by molecular dissociation are a significant source of photons, further complicating interpretation of the gas puff imaging results

  8. Influence of nonlinear effects on the neutral gas transport in tokamaks

    International Nuclear Information System (INIS)

    Behringer, T.

    1992-06-01

    The linear Monte Carlo computer code EIRENE for calculation of free molecular flow of neutral gases through a background plasma has been extended to the non-linear transition flow regime (Knudsen number 0.1-10). Motivation arose from higher gas densities in the range of 10 13 -10 15 cm -3 appearing in the srape-off layer and in parts of the vacuum system of advanced tokamak experiments. To treat the problem, the Direct Monte Carlo Simulation Method after Bird, a kinetic approach, was chosen, since the conditions for application of continuum theory are not met. First results with the extended code were obtained in calculating the conductance of plasma-free short cylindrical ducts and elbows. A steady increase in conductance with decreasing Knudsen number was found, which is in good agreement with experimental data. Further calculations for transition flows through fixed background plasmas were made. In these, solutions obtained were represented as differences from solutions obtained by linear calculations. Simulation of a 1-D plasma slab configuration (related to the gaseous divertor concept) revealed markedly varying neutral gas profiles due to neutral-neutral collisions. In addition, in these runs neutral-neutral inelastic collision processes turned out to be negligible. Finally, neutral gas behaviour at higher densities in pump limiter geometries was studied, related to experiments on the tokamak TEXTOR. An increase in conductance in the direction to the pumps of up to 25% relative to linear results was found. Recently obtained experimental data on the impact of non-linear neutral effects upon conductance could be confirmed. (orig.) [de

  9. Neutralized transport experiment

    International Nuclear Information System (INIS)

    Roy, P.K.; Yu, S.S.; Eylon, S.; Henestroza, E.; Anders, A.; Gilson, E.P.; Bieniosek, F.M.; Greenway, W.G.; Logan, B.G.; Waldron, W.L.; Shuman, D.B.; Vanecek, D.L.; Welch, D.R.; Rose, D.V.; Thoma, C.; Davidson, R.C.; Efthimion, P.C.; Kaganovich, I.; Sefkow, A.B.; Sharp, W.M.

    2005-01-01

    Experimental details on providing active neutralization of high brightness ion beam have been demonstrated for Heavy Ion Fusion program. A K + beam was extracted from a variable-perveance injector and transported through 2.4 m long quadrupole lattice for final focusing. Neutralization was provided by a localized cathode arc plasma plug and a RF volume plasma system. Effects of beam perveance, emittance, convergence focusing angle, and axial focusing position on neutralization have been investigated. Good agreement has been observed with theory and experiment throughout the study

  10. Gas cell neutralizers (Fundamental principles)

    International Nuclear Information System (INIS)

    Fuehrer, B.

    1985-06-01

    Neutralizing an ion-beam of the size and energy levels involved in the neutral-particle-beam program represents a considerable extension of the state-of-the-art of neutralizer technology. Many different mediums (e.g., solid, liquid, gas, plasma, photons) can be used to strip the hydrogen ion of its extra electron. A large, multidisciplinary R and D effort will no doubt be required to sort out all of the ''pros and cons'' of these various techniques. The purpose of this particular presentation is to discuss some basic configurations and fundamental principles of the gas type of neutralizer cell. Particular emphasis is placed on the ''Gasdynamic Free-Jet'' neutralizer since this configuration has the potential of being much shorter than other type of gas cells (in the beam direction) and it could operate in nearly a continuous mode (CW) if necessary. These were important considerations in the ATSU design which is discussed in some detail in the second presentation entitled ''ATSU Point Design''

  11. On plasma-neutral gas interaction

    International Nuclear Information System (INIS)

    Venkataramani, N.; Mattoo, S.K.

    1980-01-01

    The importance of plasma-neutral gas interaction layer has been emphasized by pointing out its application to a wide variety of physical phenomena. The interaction of a magnetised plasma stream penetrating a neutral gas cloud is discussed in the light of Alfven's critical velocity and Varma's threshold velocity on the ionising interaction. Interaction of a moving magnetised plasma with a stationary neutral gas has been studied and described. The device comprises of a plasma gun and an interaction region where neutral gas cloud is injected. The interaction region is provided with a transverse magnetic field of upto 1000 G. Several diagnostics deployed at the interaction region to make measurements on the macroscopic parameters of plasma and neutral gas are described. The parameters of discharge circuits are measured with high current and voltage probes. An interaction between a magnetised plasma stream and a neutral gas cloud is demonstrated. It is shown that this interaction does not have Varma's threshold on their relative velocity. The Alfven's critical velocity phenomenon is shown to depend on the integrated column neutral gas density that a plasma stream encounters while penetrating through it and not on the neutral gas density in the range of 10 17 -10 21 m -3 . (auth.)

  12. Ballistic-neutralized chamber transport of intense heavy ion beams

    International Nuclear Information System (INIS)

    Rose, D.V.; Welch, D.R.; Oliver, B.V.; Clark, R.E.; Sharp, W.M.; Friedman, A.

    2001-01-01

    Two-dimensional particle-in-cell simulations of intense heavy ion beams propagating in an inertial confinement fusion (ICF) reactor chamber are presented. The ballistic-neutralized transport scheme studied uses 4 GeV Pb +1 ion beams injected into a low-density, gas-filled reactor chamber and the beam is ballistically focused onto an ICF target before entering the chamber. Charge and current neutralization of the beam is provided by the low-density background gas. The ballistic-neutralized simulations include stripping of the beam ions as the beam traverses the chamber as well as ionization of the background plasma. In addition, a series of simulations are presented that explore the charge and current neutralization of the ion beam in an evacuated chamber. For this vacuum transport mode, neutralizing electrons are only drawn from sources near the chamber entrance

  13. Measurement of plasma production and neutralization in gas neutralizers

    International Nuclear Information System (INIS)

    Maor, D.; Meron, M.; Johnson, B.; Jones, K.; Agagu, A.; Hu, B.

    1986-01-01

    In order to satisfy the need of experimental data for the designing of gas neutralizers we have started a project aimed at measuring all relevant cross sections for the charge exchange of H - , H 0 and H + projectiles, as well as the cross sections for the production of ions in the target. The expected results of these latter measurements are shown schematically

  14. NATURAL GAS TRANSPORTATION

    OpenAIRE

    Stanis³aw Brzeziñski

    2007-01-01

    In the paper, Author presents chosen aspects of natural gas transportation within global market. Natural gas transportation is a technicaly complicated and economicly expensive process; in infrastructure construction and activities costs. The paper also considers last and proposed initiatives in natural gas transportation.

  15. Greenhouse gas neutral Germany in 2050

    International Nuclear Information System (INIS)

    Benndorf, Rosemarie; Bernicke, Maja; Bertram, Andreas

    2014-01-01

    In order to answer the question how a greenhouse gas neutral Germany would look like an interdisciplinary process was started by the Federal Environmental Agency. It was clear from the beginning of this work that a sustainable regenerative energy supply could not be sufficient. Therefore all relevant emission sources were included into the studies: traffic, industry, waste and waste water, agriculture, land usage, land usage changes and forestry. The necessary transformation paths to reach the aim of a greenhouse gas neutral Germany in 2050, economic considerations and political instruments were not part of this study.

  16. Modelling of neutral particle transport in divertor plasma

    International Nuclear Information System (INIS)

    Kakizuka, Tomonori; Shimizu, Katsuhiro

    1995-01-01

    An outline of the modelling of neutral particle transport in the diverter plasma was described in the paper. The characteristic properties of divertor plasma were largely affected by interaction between neutral particles and divertor plasma. Accordingly, the behavior of neutral particle should be investigated quantitatively. Moreover, plasma and neutral gas should be traced consistently in the plasma simulation. There are Monte Carlo modelling and the neutral gas fluid modelling as the transport modelling. The former need long calculation time, but it is able to make the physical process modelling. A ultra-large parallel computer is good for the former. In spite of proposing some kinds of models, the latter has not been established. At the view point of reducing calculation time, a work station is good for the simulation of the latter, although some physical problems have not been solved. On the Monte Carlo method particle modelling, reducing the calculation time and introducing the interaction of particles are important subjects to develop 'the evolutional Monte Carlo Method'. To reduce the calculation time, two new methods: 'Implicit Monte Carlo method' and 'Free-and Diffusive-Motion Hybrid Monte-Carlo method' have been developing. (S.Y.)

  17. Natural gas marketing and transportation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This book covers: Overview of the natural gas industry; Federal regulation of marketing and transportation; State regulation of transportation; Fundamentals of gas marketing contracts; Gas marketing options and strategies; End user agreements; Transportation on interstate pipelines; Administration of natural gas contracts; Structuring transactions with the nonconventional source fuels credit; Take-or-pay wars- a cautionary analysis for the future; Antitrust pitfalls in the natural gas industry; Producer imbalances; Natural gas futures for the complete novice; State non-utility regulation of production, transportation and marketing; Natural gas processing agreements and Disproportionate sales, gas balancing, and accounting to royalty owners

  18. H- beam neutralization measurements in a solenoidal beam transport system

    International Nuclear Information System (INIS)

    Sherman, J.; Pitcher, E.; Stevens, R.; Allison, P.

    1992-01-01

    H minus beam space-charge neutralization is measured for 65-mA, 35-keV beams extracted from a circular-aperture Penning surface-plasma source, the small-angle source. The H minus beam is transported to a RFQ matchpoint by a two-solenoid magnet system. Beam noise is typically ±4%. A four-grid analyzer is located in a magnetic-field-free region between the two solenoid magnets. H minus potentials are deduced from kinetic energy measurements of particles (electrons and positive ions) ejected radially from the beam channel by using a griddled energy analyzer. Background neutral gas density is increased by the introduction of additional Xe and Ar gases, enabling the H minus beam to become overneutralized

  19. Impact of neutral density fluctuations on gas puff imaging diagnostics

    Science.gov (United States)

    Wersal, C.; Ricci, P.

    2017-11-01

    A three-dimensional turbulence simulation of the SOL and edge regions of a toroidally limited tokamak is carried out. The simulation couples self-consistently the drift-reduced two-fluid Braginskii equations to a kinetic equation for neutral atoms. A diagnostic neutral gas puff on the low-field side midplane is included and the impact of neutral density fluctuations on D_α light emission investigated. We find that neutral density fluctuations affect the D_α emission. In particular, at a radial distance from the gas puff smaller than the neutral mean free path, neutral density fluctuations are anti-correlated with plasma density, electron temperature, and D_α fluctuations. It follows that the neutral fluctuations reduce the D_α emission in most of the observed region and, therefore, have to be taken into account when interpreting the amplitude of the D_α emission. On the other hand, higher order statistical moments (skewness, kurtosis) and turbulence characteristics (such as correlation length, or the autocorrelation time) are not significantly affected by the neutral fluctuations. At distances from the gas puff larger than the neutral mean free path, a non-local shadowing effect influences the neutral density fluctuations. There, the D_α fluctuations are correlated with the neutral density fluctuations, and the high-order statistical moments and measurements of other turbulence properties are strongly affected by the neutral density fluctuations.

  20. Germany 2050 a greenhouse gas-neutral country. Background paper

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kathrin; Nissler, Diana (eds.)

    2013-10-15

    For several years, the German Federal Environment Agency (UBA) has been looking at the question how the climate target of a GHG-neutral Germany can be achieved. In a multi-disciplinary project launched by the agency, the first point of call was power generation because of its high emissions. It was shown in 2010 that power generation from 100 % renewable energy is possible. Even then it was understood that a renewable energy supply alone would not be enough to completely abolish greenhouse gas emissions. Other sectors of the economy would have to follow suit and undergo major changes, relying on low-GHG technology. Consequently, the study now submitted, ''Greenhouse gas-neutral Germany 2050'', includes in its research all relevant emission sources that are described in the annual National Inventory Report (NIR) on emissions and removal of greenhouse gases. Alongside complete energy supply, including heating and transport, we also look at emissions from industry, waste disposal, agriculture and forestry as well as changes in land use. We develop a target scenario. The transformations that lead to the target and related economic considerations or the selection of appropriate policy instruments, however, are not part of our study. The scenario analysis is based on the assumption that in 2050, Germany will still be an exporting industrial country with an average annual growth of 0.7 % of its gross domestic product.

  1. Ion-neutral transport through quadrupole interfaces of mass-spectrometer systems

    International Nuclear Information System (INIS)

    Jugroot, M.; Groth, C.P.T.; Thomson, B.A.; Baranov, V.; Collings, B.A.; French, J.B.

    2004-01-01

    The transport of free ions through highly under-expanded jet flows of neutral gases and in the presence of applied electric fields is investigated by continuum-based numerical simulations. In particular, numerical results are described which are relevant to ion flows occurring in quadrupole interfaces of mass spectrometer systems. A five-moment mathematical model and parallel multi-block numerical solution procedure is developed for predicting the ion transport. The model incorporates the effects of ion-neutral collision processes and is used in conjunction with a Navier-Stokes model and flow solver for the neutral gas to examine the key influences controlling the ion motion. The effects of the neutral gas flow, electric fields (both dc and rf), and flow field geometry on ion mobility are carefully assessed. The capability of controlling the charged particle motions through a combination of directed neutral flow and applied electric field is demonstrated for these high-speed, hypersonic, jet flows. (author)

  2. Landfill Gas | Climate Neutral Research Campuses | NREL

    Science.gov (United States)

    Landfill Gas Landfill Gas For campuses located near an active or recently retired landfill , landfill gas offers an opportunity to derive significant energy from a renewable energy resource. The following links go to sections that describe when and where landfill gas systems may fit into your climate

  3. Transportation Options | Climate Neutral Research Campuses | NREL

    Science.gov (United States)

    Transportation Options Transportation Options Transportation to, from, and within a research campus from business travel often enlarge the footprint more than expected. To understand options for climate

  4. Neutral transport and helium pumping of ITER

    International Nuclear Information System (INIS)

    Ruzic, D.N.

    1990-08-01

    A 2-D Monte-Carlo simulation of the neutral atom densities in the divertor, divertor throat and pump duct of ITER was made using the DEGAS code. Plasma conditions in the scrape-off layer and region near the separatrix were modeled using the B2 plasma transport code. Wall reflection coefficients including the effect of realistic surface roughness were determined by using the fractal TRIM code. The DEGAS and B2 coupling was iterated until a consistent recycling was predicted. Results were obtained for a helium and a deuterium/tritium mixture on 7 different ITER divertor throat geometries for both the physics phase reference base case and a technology phase case. The geometry with a larger structure on the midplane-side of the throat opening closing the divertor throat and a divertor plate which maintains a steep slope well into the throat removed helium 1.5 times better than the reference geometry for the physics phase case and 2.2 times better for the technology phase case. At the same time the helium to hydrogen pumping ratio shows a factor of 2.34 ± .41 enhancement over the ratio of helium to hydrogen incident on the divertor plate in the physics phase and an improvement of 1.61 ± .31 in the technology phase. If the helium flux profile on the divertor plate is moved outward by 20 cm with respect to the D/T flux profile for this particular geometry, the enhancement increases to 4.36 ± .90 in the physics phase and 5.10 ± .92 in the technology phase

  5. Physics of gas breakdown for ion beam transport in gas

    International Nuclear Information System (INIS)

    Olson, C.L.; Poukey, J.W.; Hinshelwood, D.D.; Rose, D.V.; Hubbard, R.F.; Lampe, M.; Neri, J.M.; Ottinger, P.F.; Slinker, S.P.; Stephanakis, S.J.; Young, F.C.; Welch, D.R.

    1993-01-01

    Detailed analysis, experiments, and computer simulations are producing a new understanding of gas breakdown during intense ion beam transport in neutral gas. Charge neutralization of beam micro clumps is shown to limit the net clump potentials to a non-zero value π min , which can lead to divergence growth and axial energy spreading. At pressures approx-gt 1 Torr, plasma shielding should substantially reduce this effect Current neutralization has been studied in experiments on the GAMBLE II accelerator. The importance of fast electrons (knockons and runaways) has been established in IPROP simulations, which are in agreement with the experiments. For light ion fusion parameters with pressures approx-gt 1 Torr, very small net current fractions (much-lt 1%) appear feasible, permitting ballistic transport in gas. Self-pinched requires higher net current fractions (≥ 2%) and preliminary IPROP code results indicate that this appears achievable for small-radius intense beams in lower pressure gases (approx-gt Torr). Several self-pinched transport concepts look promising. The importance of these results for both light ion fusion and heavy ion fusion is discussed

  6. Edge momentum transport by neutrals: an interpretive numerical framework

    Science.gov (United States)

    Omotani, J. T.; Newton, S. L.; Pusztai, I.; Viezzer, E.; Fülöp, T.; The ASDEX Upgrade Team

    2017-06-01

    Due to their high cross-field mobility, neutrals can contribute to momentum transport even at the low relative densities found inside the separatrix and they can generate intrinsic rotation. We use a charge-exchange dominated solution to the neutral kinetic equation, coupled to neoclassical ions, to evaluate the momentum transport due to neutrals. Numerical solutions to the drift-kinetic equation allow us to cover the full range of collisionality, including the intermediate levels typical of the tokamak edge. In the edge there are several processes likely to contribute to momentum transport in addition to neutrals. Therefore, we present here an interpretive framework that can evaluate the momentum transport through neutrals based on radial plasma profiles. We demonstrate its application by analysing the neutral angular momentum flux for an L-mode discharge in the ASDEX Upgrade tokamak. The magnitudes of the angular momentum fluxes we find here due to neutrals of 0.6-2 \\text{N} \\text{m} are comparable to the net torque on the plasma from neutral beam injection, indicating the importance of neutrals for rotation in the edge.

  7. Transport of neutral atoms and molecules in TFCX

    International Nuclear Information System (INIS)

    Boley, C.D.

    1984-09-01

    The distribution of neutrals in the proposed reactor TFCX has been modeled by the 3-D Monte Carlo neutral transport code DEGAS, which has been run in conjunction with the 1-1/2-D time-dependent plasma transport code WHIST. The former code contains the best available treatment of neutral-particle physics, including a selection of wall reflection models. The latter code has a comprehensive set of plasma transport coefficients, an MHD equilibrium package, and provision for source terms such as those involving neutrals. It has a simple scrape-off model involving sound-speed flow to the neutralizer plates. The codes are run in iteration, so that the flux-surface averaged particle and energy sources due to interactions with neutrals are consistent with the plasma profiles. The design considered here has a bottom limiter with a pumping plenum. Results are given for the power balance, the mutually consistent plasma and neutral distributions set up in the edge region, the neutral density in the plenum, and the charge-exchange power deposition and erosion along the limiter

  8. Modeling of modification experiments involving neutral-gas release

    International Nuclear Information System (INIS)

    Bernhardt, P.A.

    1983-01-01

    Many experiments involve the injection of neutral gases into the upper atmosphere. Examples are critical velocity experiments, MHD wave generation, ionospheric hole production, plasma striation formation, and ion tracing. Many of these experiments are discussed in other sessions of the Active Experiments Conference. This paper limits its discussion to: (1) the modeling of the neutral gas dynamics after injection, (2) subsequent formation of ionosphere holes, and (3) use of such holes as experimental tools

  9. Strategic regulation of gas transport

    International Nuclear Information System (INIS)

    Nese, Gjermund; Straume, Odd Rune

    2005-01-01

    The basis of the article has been the steadily increasing focus particularly from EU, on increased competition in the natural gas markets. This could influence the profit distribution between the gas producing and consuming counties which is an important problem situation for Norway as a gas producer. The gas market value chain consist of three parts (production, transport and distribution). How the countries may use strategic regulation of the transport tariff for the transport and distribution systems in order to move as much as possible of the total profit to the part of the value chain in control is studied. The focus has been on how increased competition influences the incentives of the authorities through low or high transport tariff and to what extent increased competition influences the welfare level in the producer and consumer counties when strategic regulations of the transport occur. The analysis is based on a theoretical model developed in 2005. Some central mechanisms related to the natural gas market are mapped and Norway may counteract some negative effects of liberalisation of the European gas market through strategic adaptation of the transport tariff to the Norwegian gas transport systems

  10. GASDUC-3: a gas pipeline with neutralization of greenhouse gases

    Energy Technology Data Exchange (ETDEWEB)

    D' Oliveira, Celso A.; Paula, Eliane H. de; Freire, Dilian A.D. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    PETROBRAS seeks to develop its projects following the contemporary premises of sustainable development. The Cabiunas-REDUC-3 Gas Pipeline (GASDUC-3), an undertaking from the Transportadora Associada de Gas - TAG (Associated Gas Transporter) in progress by PETROBRAS, is an example showing that interfacing with the environment can overcome legal questions to reach the realm of awareness and community spirit. In addition to the many programs directed specifically towards the fulfillment of environmental regulations, as defined by competent agencies, the GASDUC-3 is also inserted in the Carbon Free Program. In the Carbon Free Program, all the GHG emissions into the atmosphere during the construction of the gas pipeline will be compensated for with the neutralization of carbon through reforestation. Such initiative is considered unheard of in works with pipelines worldwide. An inventory that quantified the emission of GHG during the implementation of GASDUC-3 made it possible to quantify the reforestation to be implemented and to calculate the number of native species to be planted for absorption - during the course of their growth - of this same amount of carbon dioxide from the atmosphere. The trees are being planted especially in Permanent Preservation Areas (PPA), located in the Unidades de Conservacao do Bioma Mata Atlantica (Conservation Units of the Atlantic Forest Biome), inside the influence region of the gas pipeline, in accordance with the competent environmental agencies and owners. In this way, in addition to fixing carbon and contributing to the deceleration of global warming, the project also cooperates with the preservation of hydro and soil resources and the local and regional biodiversity. The recapturing of the already emitted GHG through reforestation faces bureaucratic and economic difficulties in order to be implemented, different from the emission reduction projects which are widely disseminated by means of Clean Development Mechanisms (CDM

  11. Gas transport in porous media

    CERN Document Server

    Ho, Clifford K

    2006-01-01

    This book presents a compilation of state-of-the art studies on gas and vapor transport processes in porous and fractured media. A broad set of models and processes are presented, including advection/diffusion, the Dusty Gas Model, enhanced vapor diffusion, phase change, coupled processes, solid/vapor sorption, and vapor-pressure lowering. Numerous applications are also presented that illustrate these processes and models in current problems facing the scientific community. This book fills a gap in the general area of transport in porous and fractured media; an area that has historically been dominated by studies of liquid-phase flow and transport. This book identifies gas and vapor transport processes that may be important or dominant in various applications, and it exploits recent advances in computational modeling and experimental methods to present studies that distinguish the relative importance of various mechanisms of transport in complex media.

  12. Gas Transport in Bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Gutierre-Rodrigo, V.; Martin, P. I.; Romero, F. J.; Barcala, J. M.

    2013-07-01

    The gas permeability of the Spanish FEBEX bentonite compacted at dry densities of between 1.4 and 1.8 g/cm{sup 3} with high water contents was measured for different confining, injection and back pressures. The results were compared with results obtained in previous investigations for lower degrees of saturation. It was checked that gas permeability was greatly affected by dry density, decreasing about three orders of magnitude when it increased from 1.5 to 1.8 g/cm{sup 3} for similar water content. The increase of water content caused also a decrease in gas permeability. It was found that both gas permeability and the relative gas permeability were mainly related to the accessible porosity. These relationships could be fitted to potential expressions with exponents between 3 and 4, as well as the relationship between intrinsic permeability and void ratio. For gas pressures below 1.2 MPa no effect of the injection or confining pressures on the value of permeability was detected. For a given confining pressure the permeability value decreased as the effective pressure increased, especially if the increase in effective pressure was due to a decrease in gas back pressure. It was checked that the Klinkenberg effect was not significant for this material in the range of pressures applied in the tests. The gas breakthrough pressure values in FEBEX saturated bentonite were determined for different dry densities. They increased clearly with dry density and were always higher than the swelling pressure of the bentonite. In high density samples gas flow tended to stop abruptly after breakthrough, whereas in lower density samples gas flow decreased gradually until a given pressure gradient was reached. The permeabilities computed after breakthrough (which usually did not stabilise) were inversely related to dry density. This would indicate that, even if the flow took place predominantly through preferential pathways that sometimes closed quickly after breakthrough and others

  13. Gas Transport in Bentonite

    International Nuclear Information System (INIS)

    Villar, M. V.; Gutierrez-Rodrigo, V.; Martin, P. L.; Romero, F. J.; Barcala, J. M.

    2013-01-01

    The gas permeability of the Spanish FEBEX bentonite compacted at dry densities of between 1.4 and 1.8 g/cm 3 with high water contents was measured for different confining, injection and back pressures. The results were compared with results obtained in previous investigations for lower degrees of saturation. It was checked that gas permeability was greatly affected by dry density, decreasing about three orders of magnitude when it increased from 1.5 to 1.8 g/cm 3 for similar water content. The increase of water content caused also a decrease in gas permeability. It was found that both gas permeability and the relative gas permeability were mainly related to the accessible porosity. These relationships could be fitted to potential expressions with exponents between 3 and 4, as well as the relationship between intrinsic permeability and void ratio. For gas pressures below 1.2 MPa no effect of the injection or confining pressures on the value of permeability was detected. For a given confining pressure the permeability value decreased as the effective pressure increased, especially if the increase in effective pressure was due to a decrease in gas back pressure. It was checked that the Klinkenberg effect was not significant for this material in the range of pressures applied in the tests. The gas breakthrough pressure values in FEBEX saturated bentonite were determined for different dry densities. They increased clearly with dry density and were always higher than the swelling pressure of the bentonite. In high density samples gas flow tended to stop abruptly after breakthrough, whereas in lower density samples gas flow decreased gradually until a given pressure gradient was reached. The permeabilities computed after breakthrough (which usually did not stabilise) were inversely related to dry density. This would indicate that, even if the flow took place predominantly through preferential pathways that sometimes closed quickly after breakthrough and others remained

  14. Two dimensional neutral transport analysis in tokamak plasma

    International Nuclear Information System (INIS)

    Shimizu, Katsuhiro; Azumi, Masafumi

    1987-02-01

    Neutral particle influences the particle and energy balance, and play an important role on sputtering impurity and the charge exchange loss of neutral beam injection. In order to study neutral particle behaviour including the effects of asymmetric source and divertor configuration, the two dimensional neutral transport code has been developed using the Monte-Carlo techniques. This code includes the calculation of the H α radiation intensity based on the collisional-radiation model. The particle confinement time of the joule heated plasma in JT-60 tokamak is evaluated by comparing the calculated H α radiation intensity with the experimental data. The effect of the equilibrium on the neutral density profile in high-β plasma is also investigated. (author)

  15. Neutralization principles for the Extraction and Transport of Ion Beams

    CERN Document Server

    Riege, H

    2000-01-01

    The strict application of conventional extraction techniques of ion beams from a plasma source is characterized by a natural intensity limit determined by space charge.The extracted current may be enhanced far beyond this limit by neutralizing the space charge of the extracted ions in the first extraction gap of the source with electrons injected from the opposite side. The transverse and longitudinal emittances of a neutralized ion beam, hence its brightness, are preserved. Results of beam compensation experiments, which have been carried out with a laser ion source, are resumed for proposing a general scheme of neutralizing ion sources and their adjacent low-energy beam transport channels with electron beams. Many technical applications of high-mass ion beam neutralization technology may be identified: the enhancement of ion source output for injection into high-intensity, low-and high-energy accelerators, or ion thrusters in space technology, for the neutral beams needed for plasma heating of magnetic conf...

  16. Coarse Grained Transport Model for Neutrals in Turbulent SOL Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Marandet, Y.; Mekkaoui, A.; Genesio, P.; Rosato, J.; Capes, H.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R., E-mail: yannick.marandet@univ-amu.fr [PIIM, CNRS/Aix-Marseille University, Marseille (France); Reiter, D.; Boerner, P. [IEK4, FZJ, Juelich (Germany)

    2012-09-15

    Full text: Edge plasmas of magnetic fusion devices exhibit strong intermittent turbulence, which governs perpendicular transport of particles and heat. Turbulent fluxes result from the coarse graining procedure used to derive the transport equation, which entails time averaging of the underlying equations governing the turbulent evolution of the electron and ion fluids. In previous works, we have pointed out that this averaging is not carried out on the Boltzmann equation that describes the transport of neutral particles (atoms, molecules) in current edge code suites (such as SOLPS). Since fluctuations in the far SOL are of order unity, calculating the transport of neutral particles, hence the source terms in plasma fluid equations, in the average plasma background might lead to misleading results. In particular, retaining the effects of fluctuations could affect the estimation of the importance of main chamber recycling, hence first wall sputtering by charge exchange atoms, as well as main chamber impurity contamination and transport. In this contribution, we obtain an exact coarse-grained equation for the average neutral density, assuming that density fluctuations are described by multivariate Gamma statistics. This equation is a scattering free Boltzmann equation, where the ionization rate has been renormalized to account for fluctuations. The coarse grained transport model for neutrals has been implemented in the EIRENE code, and applications in 2D geometry with ITER relevant plasma parameters are presented. Our results open the way for the implementation of the effects of turbulent fluctuations on the transport of neutral particles in coupled plasma/neutral edge codes like B2-EIRENE. (author)

  17. Discrete elements method of neutral particle transport

    International Nuclear Information System (INIS)

    Mathews, K.A.

    1983-01-01

    A new discrete elements (L/sub N/) transport method is derived and compared to the discrete ordinates S/sub N/ method, theoretically and by numerical experimentation. The discrete elements method is more accurate than discrete ordinates and strongly ameliorates ray effects for the practical problems studied. The discrete elements method is shown to be more cost effective, in terms of execution time with comparable storage to attain the same accuracy, for a one-dimensional test case using linear characteristic spatial quadrature. In a two-dimensional test case, a vacuum duct in a shield, L/sub N/ is more consistently convergent toward a Monte Carlo benchmark solution than S/sub N/, using step characteristic spatial quadrature. An analysis of the interaction of angular and spatial quadrature in xy-geometry indicates the desirability of using linear characteristic spatial quadrature with the L/sub N/ method

  18. Electron effects in the Neutralized Transport Experiment (NTX)

    Energy Technology Data Exchange (ETDEWEB)

    Eylon, S. [Lawrence Berkeley National Laboratory (LBNL), MS47R 0112, 1 Cyclotron Road, Berkeley, CA 94720 (United States) and Heavy Ion Fusion Virtual National Laboratory, Cyclotron Road, CA 94720 (United States)]. E-mail: S_Eylon@lbl.gov; Henestroza, E. [Lawrence Berkeley National Laboratory (LBNL), MS47R 0112, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Heavy Ion Fusion Virtual National Laboratory, Cyclotron Road, CA 94720 (United States); Roy, P.K. [Lawrence Berkeley National Laboratory (LBNL), MS47R 0112, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Heavy Ion Fusion Virtual National Laboratory, Cyclotron Road, CA 94720 (United States); Yu, S.S. [Lawrence Berkeley National Laboratory (LBNL), MS47R 0112, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Heavy Ion Fusion Virtual National Laboratory, Cyclotron Road, CA 94720 (United States)

    2005-05-21

    The Neutralized Transport Experiment (NTX) at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high-perveance heavy ion beams. To focus a high-intensity beam to a small spot requires a high-brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce-type diode. At the diode exit, an aperture with variable opening provides the capability to vary the beam perveance. The beam is transported through four quadrupole magnets to a distance of 2.5 m. The beam can be neutralized and focused using a MEVVA plasma plug and a RF plasma source. We shall report on the measurement of the electron effects and the ways to mitigate the effects. Furthermore, we shall present the results of EGUN calculations consistent with the measurements effects of the electrons.

  19. Electron effects in the Neutralized Transport Experiment (NTX)

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.; Roy, P.K.; Yu, S.S.

    2005-01-01

    The Neutralized Transport Experiment (NTX) at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high-perveance heavy ion beams. To focus a high-intensity beam to a small spot requires a high-brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce-type diode. At the diode exit, an aperture with variable opening provides the capability to vary the beam perveance. The beam is transported through four quadrupole magnets to a distance of 2.5 m. The beam can be neutralized and focused using a MEVVA plasma plug and a RF plasma source. We shall report on the measurement of the electron effects and the ways to mitigate the effects. Furthermore, we shall present the results of EGUN calculations consistent with the measurements effects of the electrons

  20. Electron effects in the Neutralized Transport Experiment (NTX)

    Science.gov (United States)

    Eylon, S.; Henestroza, E.; Roy, P. K.; Yu, S. S.

    2005-05-01

    The Neutralized Transport Experiment (NTX) at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high-perveance heavy ion beams. To focus a high-intensity beam to a small spot requires a high-brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce-type diode. At the diode exit, an aperture with variable opening provides the capability to vary the beam perveance. The beam is transported through four quadrupole magnets to a distance of 2.5 m. The beam can be neutralized and focused using a MEVVA plasma plug and a RF plasma source. We shall report on the measurement of the electron effects and the ways to mitigate the effects. Furthermore, we shall present the results of EGUN calculations consistent with the measurements effects of the electrons.

  1. Observational Constraints on a Pluto Torus of Circumsolar Neutral Gas

    Science.gov (United States)

    Hill, M. E.; Kollmann, P.; McNutt, R. L., Jr.; Smith, H. T.; Bagenal, F.; Brown, L. E.; Elliott, H. A.; Haggerty, D. K.; Horanyi, M.; Krimigis, S. M.; Kusterer, M. B.; Lisse, C. M.; McComas, D. J.; Piquette, M. R.; Sidrow, E. J.; Strobel, D. F.; Szalay, J.; Vandegriff, J. D.; Zirnstein, E.; Ennico Smith, K.; Olkin, C.; Weaver, H. A., Jr.; Young, L. A.; Stern, S. A.

    2015-12-01

    We present the concept of a neutral gas torus surrounding the Sun, aligned with Pluto's orbit, and place observational constraints based primarily on comparison of New Horizons (NH) measurements with a 3-D Monte Carlo model adapted from analogous satellite tori surrounding Saturn and Jupiter. Such a torus, or perhaps partial torus, should result from neutral N2 escaping from Pluto's exosphere. Unlike other more massive planets closer to the Sun, neutrals escape Pluto readily owing, e.g., to the high thermal speed relative to the escape velocity. Importantly, escaped neutrals have a long lifetime due to the great distance from the Sun, ~100 years for photoionization of N2 and ~180 years for photoionization of N, which results from disassociated N2. Despite the lengthy 248-year orbit, these long e-folding lifetimes may allow an enhanced neutral population to form an extended gas cloud that modifies the N2 spatial profile near Pluto. These neutrals are not directly observable by NH but once ionized N2+ or N+ are picked up by the solar wind, reaching ~50 keV, making these pickup ions (PUIs) detectable by NH's Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument. PEPSSI observations analyzed to date may constrain the N2 density; the remaining ~95% of the encounter data, scheduled for downlink in August along with similarly anticipated data from the Solar Wind Around Pluto (SWAP) experiment, should help determine the Pluto outgassing rates. Measurements from SWAP include the solar wind speed, a quantity that greatly enhances PUI studies by enabling us to directly account for the PUI distribution's sensitive dependence on plasma speed. Note that anomalous cosmic ray Si observed at Voyager is overabundant by a factor of ~3000 relative to interstellar composition. This might be related to "outer source" PUIs, but the fact that N2 and Si are indistinguishable in many instruments could mean that N2 is actually driving this apparent Si discrepancy.

  2. Neutral transport calculations for W VII-X. First applications to W VII-X

    International Nuclear Information System (INIS)

    Sardei, F.

    1988-01-01

    Results of neutral gas transport calculations obtained with the DEGAS code are presented for a W VII-AS model plasma and a source of neutrals due to limiter recycling. For typical profiles of the plasma parameters as predicted for an ECRH discharge, the simulation yields a radial drop of the average neutral population by a factor of 30. The neutrals are strongly localized near the limiter and have a poloidal minimum at its opposite side. For a W VII-X configuration (HS4-12), a neutral source given by a high recycling ion flux equally distributed over the wall is considered. For an ion density of 5 x 10 1 3 /cc and 30 eV edge temperature, the neutrals originating from the wall completely ionize within the ergodic region. The corresponding average energy of cx neutrals hitting the wall is less than 30 eV. Neutral penetration into the plasma locally depends on the distance between wall and separatrix

  3. Los Alamos neutral particle transport codes: New and enhanced capabilities

    International Nuclear Information System (INIS)

    Alcouffe, R.E.; Baker, R.S.; Brinkley, F.W.; Clark, B.A.; Koch, K.R.; Marr, D.R.

    1992-01-01

    We present new developments in Los Alamos discrete-ordinates transport codes and introduce THREEDANT, the latest in the series of Los Alamos discrete ordinates transport codes. THREEDANT solves the multigroup, neutral-particle transport equation in X-Y-Z and R-Θ-Z geometries. THREEDANT uses computationally efficient algorithms: Diffusion Synthetic Acceleration (DSA) is used to accelerate the convergence of transport iterations, the DSA solution is accelerated using the multigrid technique. THREEDANT runs on a wide range of computers, from scientific workstations to CRAY supercomputers. The algorithms are highly vectorized on CRAY computers. Recently, the THREEDANT transport algorithm was implemented on the massively parallel CM-2 computer, with performance that is comparable to a single-processor CRAY-YMP We present the results of THREEDANT analysis of test problems

  4. BEAM TRANSPORT AND STORAGE WITH COLD NEUTRAL ATOMS AND MOLECULES

    Energy Technology Data Exchange (ETDEWEB)

    Walstrom, Peter L. [Los Alamos National Laboratory

    2012-05-15

    A large class of cold neutral atoms and molecules is subject to magnetic field-gradient forces. In the presence of a field, hyperfine atomic states are split into several Zeeman levels. The slopes of these curves vs. field are the effective magnetic moments. By means of optical pumping in a field, Zeeman states of neutral lithium atoms and CaH molecules with effective magnetic moments of nearly {+-} one Bohr magneton can be selected. Particles in Zeeman states for which the energy increases with field are repelled by increasing fields; particles in states for which the energy decreases with field are attracted to increasing fields. For stable magnetic confinement, field-repelled states are required. Neutral-particle velocities in the present study are on the order of tens to hundreds of m/s and the magnetic fields needed for transport and injection are on the order of in the range of 0.01-1T. Many of the general concepts of charged-particle beam transport carry over into neutral particle spin-force optics, but with important differences. In general, the role of bending dipoles in charged particle optics is played by quadrupoles in neutral particle optics; the role of quadrupoles is played by sextupoles. The neutralparticle analog of charge-exchange injection into storage rings is the use of lasers to flip the state of particles from field-seeking to field-repelled. Preliminary tracking results for two neutral atom/molecule storage ring configurations are presented. It was found that orbit instabilities limit the confinment time in a racetrack-shaped ring with discrete magnetic elements with drift spaces between them; stable behavior was observed in a toroidal ring with a continuous sextupole field. An alternative concept using a linear sextupole or octupole channel with solenoids on the ends is presently being considered.

  5. Gas transport in graphitic materials

    International Nuclear Information System (INIS)

    Hoinkis, E.

    1995-02-01

    The characterization of the gas transport properties of porous solids is of interest in several fields of science and technology. Many catalysts, adsorbents, soils, graphites and carbons are porous. The gas transport through most porous solids can be well described by the dusty gas model invented by Evans, Watson and Mason. This model includes all modes of gas tranport under steady-state conditions, which are Knudsen diffusion, combined Knudsen/continuum diffusion and continuum diffusion, both for gas pairs with equal and different molecular weights. In the absence of a pressure difference gas transport in a pore system can be described by the combined Knudsen/continuum diffusion coefficient D 1 for component 1 in the pores, the Knudsen diffusion coefficient D 1K in the pores, and the continuum diffusion coefficient D 12 for a binary mixture in the pores. The resistance to stationary continuum diffusion of the pores is characterized by a geometrical factor (ε/τ) 12 = (ε/τ)D 12 , were D 12 is the continuum diffusion coefficient for a binary mixture in free space. The Wicke-Kallenbach method was often used to measure D 1 as function of pressure. D 12 and D 1K can be derived from a plot 1/D 1 νs P, and ε/τcan be calculated since D 12 is known. D 1K and the volume of dead end pores can be derived from transient measurements of the diffusional flux at low pressures. From D 1K the expression (ε/τ c ) anti l por may be calculated, which characterizes the pore system for molecular diffusion, where collisions with the pore walls are predominant. (orig.)

  6. Strategic regulation of gas transport

    International Nuclear Information System (INIS)

    Nese, Gjermund; Straume, Odd Rune

    2005-02-01

    The basis of the article has been the growing focus on competition within the natural gas markets particularly in the EU. Increased competition whether upstream or downstream may influence the distribution of profit between producing and consuming countries. For Norway as a large exporter of natural gas to the European market this would be an important problem. The chain of values in the gas market consists of three complementary parts (production, problem definition and distribution). With this in mind it is studied how the countries would use strategic availability pricing for transport and distribution systems for moving as large a part of the total profit as possible to the parts of the chain of value they control themselves. The focus has been on how increased competition in the market for natural gas influence the authority incentives for stipulating a high or low availability price and to what extent increased competition influence the welfare level in the producing and consuming countries when they use strategic availability pricing. The analysis builds on a theoretical model developed by the company Nese and Straume (2005). Finally some of the more interesting results as to the Norwegian position as a gas producer are presented. One of the more surprising results was that for an exporting country and an importing country increased competition upwards may be an advantage for the exporting country while negative for the importing country. The result was valid also when a competing export country was included when this country did not use strategic availability pricing. If the competing country also acted strategically the result inverted. However, if the gas exporting countries were capable of perfect coordination of their availability pricing the case would revert to the situation with only one exporting country and the result would be valid. If a future formation of a ''gas-OPEC'' is considered where for example Norway and Russia cooperate in a gas

  7. Revised neutral gas shielding model for pellet ablation - combined neutral and plasma shielding

    International Nuclear Information System (INIS)

    Houlberg, W.A.; Schuresko, D.D.; Attenberger, S.E.

    1986-01-01

    The ablation and penetration of pellets in early ORMAK and ISX-A experiments were reliably predicted by the neutral gas shielding model of Milora and Foster. These experiments demonstrated that the principle components of the model - a self-generated shield which reduces the heat flux at the plasma surface - were correct. In more recent experiments with higher temperature plasmas, this model consistently predicts greater penetration than observed in the experiments. Upgarding known limitations of the original model brings the predicted and observed penetration values into agreement. These improvements include: (1) treating the incident electrons as having distribution in energy rather than being monoenergetic; (2) including the shielding effects of cold, dense plasma extending along the magnetic field outside the neutral shield; and (3) modifying the finite plasma, self-limiting incident heat flux so that it represents a collisionless plasma limit rather than a collisional limit. Comparisons are made between the models for a selection of ISX-B Alcator-C, and TFTR shots. The net effect of the changes in the model is an increase in pellet ablation rates and decrease in penetration for current and future experiments

  8. Recent advances in neutral particle transport methods and codes

    International Nuclear Information System (INIS)

    Azmy, Y.Y.

    1996-01-01

    An overview of ORNL's three-dimensional neutral particle transport code, TORT, is presented. Special features of the code that make it invaluable for large applications are summarized for the prospective user. Advanced capabilities currently under development and installation in the production release of TORT are discussed; they include: multitasking on Cray platforms running the UNICOS operating system; Adjacent cell Preconditioning acceleration scheme; and graphics codes for displaying computed quantities such as the flux. Further developments for TORT and its companion codes to enhance its present capabilities, as well as expand its range of applications are disucssed. Speculation on the next generation of neutron particle transport codes at ORNL, especially regarding unstructured grids and high order spatial approximations, are also mentioned

  9. Plasma-neutral gas interaction in a tokamak divertor: effects of hydrogen molecules and plasma recombination

    International Nuclear Information System (INIS)

    Krasheninnikov, S.I.; Pigarov, A.Yu.; Soboleva, T.K.; Sigmar, D.J.

    1997-01-01

    We investigate the influence of hydrogen molecules on plasma recombination using a collisional-radiative model for multispecies hydrogen plasmas and tokamak detached divertor parameters. The rate constant found for molecular activated recombination of a plasma can be as high as 2 x 10 -10 cm 3 /s, confirming our pervious estimates. We investigate the effects of hydrogen molecules and plasma recombination on self-consistent plasma-neutral gas interactions in the recycling region of a tokamak divertor. We treat the plasma flow in a fluid approximation retaining the effects of plasma recombination and employing a Knudsen neutral transport model for a 'gas box' divertor geometry. For the model of plasma-neutral interactions we employ we find: (a) molecular activated recombination is a dominant channel of divertor plasma recombination; and (b) plasma recombination is a key element leading to a decrease in the plasma flux onto the target and substantial plasma pressure drop which are the main features of detached divertor regimes. (orig.)

  10. Specific lysosomal transport of small neutral amino acids

    International Nuclear Information System (INIS)

    Pisoni, R.L.; Flickinger, K.S.; Thoene, J.G.; Christensen, H.N.

    1986-01-01

    Studies of amino acid exodus from lysosomes have allowed us previously to describe transport systems specific for cystine and another for cationic amino acids in fibroblast lysosomes. They are now able to study amino acid uptake into highly purified fibroblast lysosomes obtained by separating crude granular fraction on gradients formed by centrifugation in 35% isoosmotic Percoll solutions. Analog inhibition and saturation studies indicate that L-[ 14 C]proline (50 μM) uptake by fibroblast lysosomes at 37 0 C in 50 mM citrate/tris pH 7.0 buffer containing 0.25 M sucrose is mediated by two transport systems, one largely specific for L-proline and the other for which transport is shared with small neutral amino acids such as alanine, serine and threonine. At 7 mM, L-proline inhibits L-[ 14 C]proline uptake almost completely, whereas ala, ser, val, thr, gly, N-methylalanine and sarcosine inhibit proline uptake by 50-65%. The system shared by alanine, serine and threonine is further characterized by these amino acids strongly inhibiting the uptakes of each other. Lysosomal proline transport is selective for the L-isomer of the amino acid, and is scarcely inhibited by 7 mM arg, glu, asp, leu, phe, his, met, (methylamino) isobutyrate, betaine or N,N-dimethylglycine. Cis or trans-4-hydroxy-L-proline inhibit proline uptake only slightly. In sharp contrast to the fibroblast plasma membrane in which Na + is required for most proline and alanine transport, lysosomal uptake of these amino acids occurs independently of Na +

  11. Recently developed methods in neutral-particle transport calculations: overview

    International Nuclear Information System (INIS)

    Alcouffe, R.E.

    1982-01-01

    It has become increasingly apparent that successful, general methods for the solution of the neutral particle transport equation involve a close connection between the spatial-discretization method used and the source-acceleration method chosen. The first form of the transport equation, angular discretization which is discrete ordinates is considered as well as spatial discretization based upon a mesh arrangement. Characteristic methods are considered briefly in the context of future, desirable developments. The ideal spatial-discretization method is described as having the following attributes: (1) positive-positive boundary data yields a positive angular flux within the mesh including its boundaries; (2) satisfies the particle balance equation over the mesh, that is, the method is conservative; (3) possesses the diffusion limit independent of spatial mesh size, that is, for a linearly isotropic flux assumption, the transport differencing reduces to a suitable diffusion equation differencing; (4) the method is unconditionally acceleratable, i.e., for each mesh size, the method is unconditionally convergent with a source iteration acceleration. It is doubtful that a single method possesses all these attributes for a general problem. Some commonly used methods are outlined and their computational performance and usefulness are compared; recommendations for future development are detailed, which include practical computational considerations

  12. Entangling two transportable neutral atoms via local spin exchange.

    Science.gov (United States)

    Kaufman, A M; Lester, B J; Foss-Feig, M; Wall, M L; Rey, A M; Regal, C A

    2015-11-12

    To advance quantum information science, physical systems are sought that meet the stringent requirements for creating and preserving quantum entanglement. In atomic physics, robust two-qubit entanglement is typically achieved by strong, long-range interactions in the form of either Coulomb interactions between ions or dipolar interactions between Rydberg atoms. Although such interactions allow fast quantum gates, the interacting atoms must overcome the associated coupling to the environment and cross-talk among qubits. Local interactions, such as those requiring substantial wavefunction overlap, can alleviate these detrimental effects; however, such interactions present a new challenge: to distribute entanglement, qubits must be transported, merged for interaction, and then isolated for storage and subsequent operations. Here we show how, using a mobile optical tweezer, it is possible to prepare and locally entangle two ultracold neutral atoms, and then separate them while preserving their entanglement. Ground-state neutral atom experiments have measured dynamics consistent with spin entanglement, and have detected entanglement with macroscopic observables; we are now able to demonstrate position-resolved two-particle coherence via application of a local gradient and parity measurements. This new entanglement-verification protocol could be applied to arbitrary spin-entangled states of spatially separated atoms. The local entangling operation is achieved via spin-exchange interactions, and quantum tunnelling is used to combine and separate atoms. These techniques provide a framework for dynamically entangling remote qubits via local operations within a large-scale quantum register.

  13. Approximate models for neutral particle transport calculations in ducts

    International Nuclear Information System (INIS)

    Ono, Shizuca

    2000-01-01

    The problem of neutral particle transport in evacuated ducts of arbitrary, but axially uniform, cross-sectional geometry and isotropic reflection at the wall is studied. The model makes use of basis functions to represent the transverse and azimuthal dependences of the particle angular flux in the duct. For the approximation in terms of two basis functions, an improvement in the method is implemented by decomposing the problem into uncollided and collided components. A new quadrature set, more suitable to the problem, is developed and generated by one of the techniques of the constructive theory of orthogonal polynomials. The approximation in terms of three basis functions is developed and implemented to improve the precision of the results. For both models of two and three basis functions, the energy dependence of the problem is introduced through the multigroup formalism. The results of sample problems are compared to literature results and to results of the Monte Carlo code, MCNP. (author)

  14. Trans Ocean Gas CNG transportation development plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-11-01

    Liquefied natural gas (LNG) transportation is on the rise due to increased global demand for natural gas. However, the challenge of transporting LNG lies in finding suitable locations for import terminals. Compressed natural gas (CNG) transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets not practical for LNG or pipelines. The founder of Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. Financial support is needed to perform verification testing and for regulatory approval. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. 2 tabs., 3 figs.

  15. Gas transport in solid oxide fuel cells

    CERN Document Server

    He, Weidong; Dickerson, James

    2014-01-01

    This book provides a comprehensive overview of contemporary research and emerging measurement technologies associated with gas transport in solid oxide fuel cells. Within these pages, an introduction to the concept of gas diffusion in solid oxide fuel cells is presented. This book also discusses the history and underlying fundamental mechanisms of gas diffusion in solid oxide fuel cells, general theoretical mathematical models for gas diffusion, and traditional and advanced techniques for gas diffusivity measurement.

  16. Plans for longitudinal and transverse neutralized beam compression experiments, and initial results from solenoid transport experiments

    International Nuclear Information System (INIS)

    Seidl, P.A.; Armijo, J.; Baca, D.; Bieniosek, F.M.; Coleman, J.; Davidson, R.C.; Efthimion, P.C.; Friedman, A.; Gilson, E.P.; Grote, D.; Haber, I.; Henestroza, E.; Kaganovich, I.; Leitner, M.; Logan, B.G.; Molvik, A.W.; Rose, D.V.; Roy, P.K.; Sefkow, A.B.; Sharp, W.M.; Vay, J.L.; Waldron, W.L.; Welch, D.R.; Yu, S.S.

    2007-01-01

    This paper presents plans for neutralized drift compression experiments, precursors to future target heating experiments. The target-physics objective is to study warm dense matter (WDM) using short-duration (∼1 ns) ion beams that enter the targets at energies just above that at which dE/dx is maximal. High intensity on target is to be achieved by a combination of longitudinal compression and transverse focusing. This work will build upon recent success in longitudinal compression, where the ion beam was compressed lengthwise by a factor of more than 50 by first applying a linear head-to-tail velocity tilt to the beam, and then allowing the beam to drift through a dense, neutralizing background plasma. Studies on a novel pulse line ion accelerator were also carried out. It is planned to demonstrate simultaneous transverse focusing and longitudinal compression in a series of future experiments, thereby achieving conditions suitable for future WDM target experiments. Future experiments may use solenoids for transverse focusing of un-neutralized ion beams during acceleration. Recent results are reported in the transport of a high-perveance heavy ion beam in a solenoid transport channel. The principal objectives of this solenoid transport experiment are to match and transport a space-charge-dominated ion beam, and to study associated electron-cloud and gas effects that may limit the beam quality in a solenoid transport system. Ideally, the beam will establish a Brillouin-flow condition (rotation at one-half the cyclotron frequency). Other mechanisms that potentially degrade beam quality are being studied, such as focusing-field aberrations, beam halo, and separation of lattice focusing elements

  17. ORNL neutral gas shielding model for pellet-plasma interactions

    International Nuclear Information System (INIS)

    Milora, S.L; Foster, C.A.

    1977-05-01

    A revised neutral molecule ablation model is derived to describe the evaporation of a solid hydrogen pellet in a tokamak plasma. The approach taken is based on the theory of Parks, Turnbull, and Foster who postulate that a cloud of molecular hydrogen surrounding the pellet shields the surface from incoming energetic electrons and, in so doing, regulates the evaporation rate. This treatment differs from an earlier model in that the hydrodynamic behavior of the molecular cloud is treated in a self-consistent manner. Numerical solutions of the fluid dynamic equations, which include the effects of strong electron heating locally in the gas, reveal that the flow of material away from the pellet is initially retarded by the heating and then rapidly accelerated and rarefied. This behavior is more pronounced for higher temperature plasmas and the net effect is that pellet lifetimes are prolonged slightly by including the heating effects. A comparison is made with the results of the recent pellet injection experiments on ORMAK and a simple injection depth scaling law is derived

  18. Current neutralization in ballistic transport of light ion beams

    International Nuclear Information System (INIS)

    Hubbard, R.F.; Slinker, S.P.; Lampe, M.; Joyce, G.; Ottinger, P.

    1992-01-01

    Intense light ion beams are being considered as drivers to ignite fusion targets in the Laboratory Microfusion Facility (LMF). Ballistic transport of these beams from the diode to the target is possible only if the beam current is almost completely neutralized by plasma currents. This paper summarizes related work on relativistic electron beam and heavy ion beam propagation and describes a simple simulation model (DYNAPROP) which has been modified to treat light ion beam propagation. DYNAPROP uses an envelope equation to treat beam dynamics and uses rate equations to describe plasma and conductivity generation. The model has been applied both to the high current, 30 MeV Li +3 beams for LMF as well as low current, 1.2 MeV proton beams which are currently being studied on GAMBLE B at the Naval Research Laboratory. The predicted ratio of net currents to beam current is ∼0.1--0.2 for the GAMBLE experiment and ∼0.01 for LMF. The implications of these results for LMF and the GAMBLE experiments art discussed in some detail. The simple resistive model in DYNAPROP has well-known limitations in the 1 torr regime which arise primarily from the neglect of plasma electron transport. Alternative methods for treating the plasma response are discussed

  19. The Importance of Policy Neutrality for Lowering Greenhouse Gas Emissions

    Directory of Open Access Journals (Sweden)

    Trevor Tombe

    2013-03-01

    Full Text Available The drive by Canadian governments, at the provincial and federal level, to lower greenhouse gas emissions has resulted in a hodgepodge of different policy approaches. Some governments have opted for energy taxes, others for regulated limits on total emissions or emission intensity. Unfortunately, not all policy solutions are created equal; some are more effective than others in lowering total emissions and, worse still, may exact a heavy price on the economy. Policy-makers require a better understanding of how various policies affect the health of an economy and of how to mitigate the most pernicious costs. Key to gaining this improved understanding is to recognize one simple fact: some firms are more productive than others. As a consequence, it matters how workers, machines, energy, and other inputs are distributed between these firms. More productive firms should be larger — it is that simple. Some policies, however, increase input costs differently across firms and create costly distortions. Energy intensity targets are a clear example of a policy that disproportionately burdens lower productivity firms, changing firm sizes for the worse and even leading some to shut down altogether. Using a detailed model of production and energy use that matches the Canadian economy, we explore the consequences of the several forms that energy intensity regulations can take. We find the best approach to lowering greenhouse gas emissions is one that is neutral across firms — one that affects the cost of energy for smaller firms no more, or less, than larger ones. The only policy that fulfils this criterion is a flat energy tax. However, a flat tax on energy could well be politically unsellable in Canada, leaving governments to resort to politically palatable but economically risky intensity targets instead. Recognizing this, we explore a number of ways to improve the performance of intensity targets. First, governments should allow firms the option to

  20. Natural gas transport, regulation in UK

    International Nuclear Information System (INIS)

    Goldoni, Giovanni

    2005-01-01

    The detailed analysis contained in this case history demonstrates the great efforts made in the field of incentive regulation in order to promote competition in the gas market and to improve the efficiency of the gas transport system. The next challenge will be to preserve competition and efficiency in a quite different gas-supply condition [it

  1. Simulation of dense recombining divertor plasmas with a Navier endash Stokes neutral transport model

    International Nuclear Information System (INIS)

    Knoll, D.A.; McHugh, P.R.; Krasheninnikov, S.I.; Sigmar, D.J.

    1996-01-01

    A two-dimensional combined edge plasma Navier endash Stokes neutral transport model is presented for the simulation of dense recombining divertor plasmas. This model includes ions, electrons, and neutral atoms which undergo Coulomb collisions, electron impact ionization, ion endash neutral elastic collisions, three-body and radiative recombination, and neutral endash neutral collisions. The advanced fully implicit solution algorithm is briefly described and a variety of results on a model geometry are presented. It is shown that interesting neutral flow patterns can exist and that these flows can convect significant energy. A solution that ignores neutral endash neutral collisions is shown to be quantitatively different from one that includes neutral endash neutral collisions. Solutions are also shown to be sensitive to the plasma opacity for Lyman α radiation. copyright 1996 American Institute of Physics

  2. Three-dimensional modeling of the neutral gas depletion effect in a helicon discharge plasma

    Science.gov (United States)

    Kollasch, Jeffrey; Schmitz, Oliver; Norval, Ryan; Reiter, Detlev; Sovinec, Carl

    2016-10-01

    Helicon discharges provide an attractive radio-frequency driven regime for plasma, but neutral-particle dynamics present a challenge to extending performance. A neutral gas depletion effect occurs when neutrals in the plasma core are not replenished at a sufficient rate to sustain a higher plasma density. The Monte Carlo neutral particle tracking code EIRENE was setup for the MARIA helicon experiment at UW Madison to study its neutral particle dynamics. Prescribed plasma temperature and density profiles similar to those in the MARIA device are used in EIRENE to investigate the main causes of the neutral gas depletion effect. The most dominant plasma-neutral interactions are included so far, namely electron impact ionization of neutrals, charge exchange interactions of neutrals with plasma ions, and recycling at the wall. Parameter scans show how the neutral depletion effect depends on parameters such as Knudsen number, plasma density and temperature, and gas-surface interaction accommodation coefficients. Results are compared to similar analytic studies in the low Knudsen number limit. Plans to incorporate a similar Monte Carlo neutral model into a larger helicon modeling framework are discussed. This work is funded by the NSF CAREER Award PHY-1455210.

  3. Energy Conservation Tests of a Coupled Kinetic-kinetic Plasma-neutral Transport Code

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, D. P.; Chang, C. S.; Ku, S. H.; Lang, J.; Park, G.

    2012-08-29

    A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.

  4. Investment in transport infrastructure, regulation, and gas-gas competition

    International Nuclear Information System (INIS)

    Gasmi, Farid; Oviedo, Juan Daniel

    2010-01-01

    This paper develops a simple model in which a regulated (upstream) transporter provides capacity to a marketer competing in output with an incumbent in the (downstream) gas commodity market. The equilibrium outcome of the firms' interaction in the downstream market is explicitly taken into account by the regulator when setting the transport charge. We consider various forms of competition in this market and derive the corresponding optimal transport charge policies. We then run simulations that allow us to perform a comparative welfare analysis of these transport infrastructure investment policies based on different assumptions about the intensity of the competition that prevails in the gas commodity market. (author)

  5. Investment in transport infrastructure, regulation, and gas-gas competition

    Energy Technology Data Exchange (ETDEWEB)

    Gasmi, Farid [Toulouse School of Economics (ARQADE and IDEI), Universite Toulouse 1 Capitole (France); Oviedo, Juan Daniel [Universidad del Rosario (Colombia)

    2010-05-15

    This paper develops a simple model in which a regulated (upstream) transporter provides capacity to a marketer competing in output with an incumbent in the (downstream) gas commodity market. The equilibrium outcome of the firms' interaction in the downstream market is explicitly taken into account by the regulator when setting the transport charge. We consider various forms of competition in this market and derive the corresponding optimal transport charge policies. We then run simulations that allow us to perform a comparative welfare analysis of these transport infrastructure investment policies based on different assumptions about the intensity of the competition that prevails in the gas commodity market. (author)

  6. DANTSYS: a system for deterministic, neutral particle transport calculations

    Energy Technology Data Exchange (ETDEWEB)

    Alcouffe, R.E.; Baker, R.S.

    1996-12-31

    The THREEDANT code is the latest addition to our system of codes, DANTSYS, which perform neutral particle transport computations on a given system of interest. The system of codes is distinguished by geometrical or symmetry considerations. For example, ONEDANT and TWODANT are designed for one and two dimensional geometries respectively. We have TWOHEX for hexagonal geometries, TWODANT/GQ for arbitrary quadrilaterals in XY and RZ geometry, and THREEDANT for three-dimensional geometries. The design of this system of codes is such that they share the same input and edit module and hence the input and output is uniform for all the codes (with the obvious additions needed to specify each type of geometry). The codes in this system are also designed to be general purpose solving both eigenvalue and source driven problems. In this paper we concentrate on the THREEDANT module since there are special considerations that need to be taken into account when designing such a module. The main issues that need to be addressed in a three-dimensional transport solver are those of the computational time needed to solve a problem and the amount of storage needed to accomplish that solution. Of course both these issues are directly related to the number of spatial mesh cells required to obtain a solution to a specified accuracy, but is also related to the spatial discretization method chosen and the requirements of the iteration acceleration scheme employed as will be noted below. Another related consideration is the robustness of the resulting algorithms as implemented; because insistence on complete robustness has a significant impact upon the computation time. We address each of these issues in the following through which we give reasons for the choices we have made in our approach to this code. And this is useful in outlining how the code is evolving to better address the shortcomings that presently exist.

  7. Investigation of Sterilization Mechanism for Geobacillus stearothermophilus Spores with Plasma-Excited Neutral Gas

    Science.gov (United States)

    Matsui, Kei; Ikenaga, Noriaki; Sakudo, Noriyuki

    2015-09-01

    We investigate the mechanism of the sterilization with plasma-excited neutral gas that uniformly sterilizes both the space and inner wall of the reactor chamber at atmospheric pressure. Only reactive neutral species such as plasma-excited gas molecules and radicals are separated from the plasma and sent to the reactor chamber for chemical sterilization. The plasma source gas uses humidified mixture of nitrogen and oxygen. Geobacillus stearothermophilus spores and tyrosine which is amino acid are treated by the plasma-excited neutral gas. Shape change of the treated spore is observed by SEM, and chemical modification of the treated tyrosine is analyzed by HPLC. As a result, the surface of the treated spore shows depression. Hydroxylation and nitration of tyrosine are shown after the treatment. For these reasons, we believe that the sterilization with plasma-excited neutral gas results from the deformation of spore structure due to the chemical modification of amino acid.

  8. Effect of neutral gas heating in argon radio frequency inductively coupled plasma

    International Nuclear Information System (INIS)

    Chin, O.H.; Jayapalan, K.K.; Wong, C.S.

    2014-01-01

    Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile. (author)

  9. Precise measurements of neutral gas temperature using Fiber Bragg Grating sensor in Argon capacitively coupled plasmas

    Science.gov (United States)

    Han, Daoman; Liu, Zigeng; Liu, Yongxin; Peng, Wei; Wang, Younian

    2016-09-01

    Neutral gas temperature was measured using Fiber Bragg Grating sensor (FBGs) in capacitively coupled argon plasmas. Thermometry is based on the thermal equilibrium between the sensor and neutral gases, which is found to become faster with increasing pressure. It is also observed that the neutral gas temperature is higher than the room temperature by 10 120 °depending on the experiental conditions, and gas temperature shows significant non-uniformity in space. In addition, radial profiles of neutral temperature at different pressures, resemble these of ion density, obtained by a floating double probe. Specifically, at low pressure, neutral gas temperature and ion density peak at the center of the reactor, while the peak appears at the edge of the electrode at higher pressure. The neutral gas heating is mainly caused by the elastic collisions of Ar + with neutral gas atoms in the sheath region after Ar + gaining a certain energy. This work was supported by the National Natural Science Foundation of China (NSFC) (Grants No. 11335004, 11405018, and 61137005).

  10. Policies and initiatives for carbon neutrality in nordic heating and transport systems

    DEFF Research Database (Denmark)

    Muller, Jakob Glarbo; Wu, Qiuwei; Ostergaard, Jacob

    2012-01-01

    Policies and initiatives promoting carbon neutrality in the Nordic heating and transport systems are presented. The focus within heating systems is the propagation of heat pumps while the focus within transport systems is initiatives regarding electric vehicles (EVs). It is found that conversion...... to heat pumps in the Nordic region rely on both private economic and national economic incentives. Initiatives toward carbon neutrality in the transport system are mostly concentrated on research, development and demonstration for deployment of a large number of EVs. All Nordic countries have plans...... for the future heating and transport systems with the ambition of realizing carbon neutrality....

  11. Neutral particle transport modeling with a reflective source in the plasma edge

    International Nuclear Information System (INIS)

    Valenti, M.E.

    1992-01-01

    A reflective source term is incorporated into the Boltzmann neutral particle transport equation to account for boundary reflection. This reflective neutral model is integrated over a uniform axis and subsequently discretized. The discrete two-dimensional equations are solved iteratively with a computer code. The results of the reflective neutral model computer code are benchmarked with the neutral particle transport code ONEDANT. The benchmark process demonstrates the validity of the reflective neutral model. The reflective neutral model is coupled to the Braams plasma particle and energy transport code. The coupled system generates self-consistent plasma edge transport solutions. These solutions, which utilize the transport equation are similar to solutions which utilize simple plasma edge neutral models when high recycle divertors are modeled. In the high recycle mode, the high electron density at the divertor plate reduces the mean free path of plate neutrals. Hence, the similarity in results. It is concluded that simple neutral models are sufficient for the analysis of high recycle power reactor edge plasmas. Low recycle edge plasmas were not examined

  12. Gas utilization in TFTR [Tokamak Fusion Test Reactor] neutral beam injectors

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Gammel, G.M.; Kugel, H.W.; Grisham, L.R.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1987-08-01

    Measurements of gas utilization in a test TFTR neutral beam injector have been performed to study the feasibility of running tritium neutral beams with existing ion sources. Gas consumption is limited by the restriction of 50,000 curies of T 2 allowed on site. It was found that the gas efficiency of the present long-pulse ion sources is higher than it was with previous short-pulse sources. Gas efficiencies were studied over the range of 35 to 55%. At the high end of this range the neutral fraction of the beam fell below that predicted by room temperature molecular gas flow. This is consistent with observations made on the JET injectors, where it has been attributed to beam heating of the neutralizer gas and a concomitant increase in conductance. It was found that a working gas isotope exchange from H 2 to D 2 could be accomplished on the first beam shot after changing the gas supply, without any intermediate preconditioning. The mechanism believed responsible for this phenomenon is heating of the plasma generator walls by the arc and a resulting thermal desorption of all previously adsorbed and implanted gas. Finally, it was observed that an ion source conditioned to 120 kV operation could produce a beam pulse after a waiting period of fourteen hours by preceding the beam extraction with several hi-pot/filament warm-up pulses, without any gas consumption. 18 refs., 7 figs., 2 tabs

  13. Plasma and neutral gas jet interactions in the exhaust of a magnetic confinement system

    International Nuclear Information System (INIS)

    Krueger, W.A.

    1990-06-01

    A general purpose 2-1/2 dimensional, multifluid, time dependent computer code has been developed. This flexible tool models the dynamic behavior of plasma/neutral gas interactions in the presence of a magnetic field. The simulation has been used to examine the formation of smoke ring structure in the plasma rocket exhaust by injection of an axial jet of neutral gas. Specifically, the code was applied to the special case of attempting to couple the neutral gas momentum to the plasma in such a manner that plasma smoke rings would form, disconnecting the plasma from the magnetic field. For this scenario several cases where run scanning a wide range of neutral gas input parameters. In all the cases it was found that after an initial transient phase, the plasma eroded the neutral gas and after that followed the original magnetic field. From these findings it is concluded that smoke rings do not form with axial injection of neutral gas. Several suggestions for alternative injection schemes are presented

  14. Windowless gas target with gas-dynamical focussing of an ultrasonic neutral gas flow

    International Nuclear Information System (INIS)

    Tietsch, W.; Bethge, K.; Feist, H.; Schopper, E.

    1975-11-01

    The construction of a gas jet target for heavy ion reaction is reported on. The spatial compression strockwaves in a supersonic flow behind a laval nozzle are used as a target. The target thickness can be varied by the choice of the nozzle pressure and the static pressure in the expansion room. All gases can be used. (WL) [de

  15. Multigroup calculations of low-energy neutral transport in tokamak plasmas

    International Nuclear Information System (INIS)

    Gilligan, J.G.; Gralnick, S.L.; Price, W.G. Jr.; Kammash, T.

    1978-01-01

    Multigroup discrete ordinates methods avoid many of the approximations that have been used in previous neutral transport analyses. Of particular interest are the neutral profiles generated as an integral part of larger plasma system simulation codes. To determine the appropriateness of utilizing a particular multigroup code, ANISN, for this purpose, results are compared with the neutral transport module of the Duechs code. For a typical TFTR plasma, predicted neutral densities differ by a maximum factor of three on axis and outfluxes at the plasma boundary by approximately 40%. This is found to be significant for a neutral transport module. Possible sources of the observed discrepancies are indicated from an analysis of the approximations used in the Duechs model. Recommendations are made concerning the future application of the multigroup method. (author)

  16. Natural gas in the transportation sector

    Energy Technology Data Exchange (ETDEWEB)

    Ask, T Oe; Einang, P M; Stenersen, D [MARINTEK (Norway)

    1996-12-01

    The transportation sector is responsible for more than 50% of all oil products consumed, and it is the fastest growing oil demand sector and the fastest growing source of emissions. During the last 10 years there have been a considerable and growing effort in developing internal combustion gas engines. This effort has resulted in gas engines with efficiencies comparable to the diesel engines and with emissions considerably lower than engines burning conventional fuels. This development offers us opportunities to use natural gas very efficiently also in the transportation sector, resulting in reduced emissions. However, to utilize all the built in abilities natural gas has as engine fuel, the natural gas composition must be kept within relatively narrow limits. This is the case with both diesel and gasoline today. A further development require therefore specified natural gas compositions, and the direct use of pipeline natural gas as today would only in limited areas be acceptable. An interesting possibility for producing a specified natural gas composition is by LNG (Liquid Natural Gas) production. (EG)

  17. Inert gas transport in blood and tissues.

    Science.gov (United States)

    Baker, A Barry; Farmery, Andrew D

    2011-04-01

    This article establishes the basic mathematical models and the principles and assumptions used for inert gas transfer within body tissues-first, for a single compartment model and then for a multicompartment model. From these, and other more complex mathematical models, the transport of inert gases between lungs, blood, and other tissues is derived and compared to known experimental studies in both animals and humans. Some aspects of airway and lung transfer are particularly important to the uptake and elimination of inert gases, and these aspects of gas transport in tissues are briefly described. The most frequently used inert gases are those that are administered in anesthesia, and the specific issues relating to the uptake, transport, and elimination of these gases and vapors are dealt with in some detail showing how their transfer depends on various physical and chemical attributes, particularly their solubilities in blood and different tissues. Absorption characteristics of inert gases from within gas cavities or tissue bubbles are described, and the effects other inhaled gas mixtures have on the composition of these gas cavities are discussed. Very brief consideration is given to the effects of hyper- and hypobaric conditions on inert gas transport. © 2011 American Physiological Society. Compr Physiol 1:569-592, 2011.

  18. Advanced neutral gas diagnostics for magnetic confinement devices

    International Nuclear Information System (INIS)

    Wenzel, U.; Schlisio, G.; Marquardt, M.; Pedersen, T.S.; Kremeyer, T.; Schmitz, O.; Mackie, B.; Maisano-Brown, J.

    2017-01-01

    For the study of particle exhaust in nuclear fusion devices the neutral pressure must be measured in strong magnetic fields. We describe as an example the neutral pressure gauges in the Wendelstein 7-X stellarator. Two types are used: hot cathode ionization gauges (or ASDEX pressure gauges) and Penning gauges. We show some results from the first experimental campaign. The main problems were runtime effects and the failure of some ASDEX pressure gauges. To improve the reliability we integrated a new LaB 6 electron emitter into the ASDEX pressure gauges. In addition, a special Penning gauge without permanent magnets was developed in order to operate Penning gauges near the plasma edge. These new pressure gauges will be used in the upcoming campaign of Wendelstein 7-X.

  19. Power stabilized CO2 gas transport laser

    International Nuclear Information System (INIS)

    Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

    1975-01-01

    The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

  20. The petroleum, natural gas and bio fuel transportation; O transporte de petroleo, gas natural e biocombustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Diego Varela; Campos, Carlos Hebert

    2011-01-15

    The paper expose on the activity of petroleum, natural gas and bio fuels transportation, outlining the transportation means used by the petroleum industry. After that, analyses the importance and the economic relevance of the Transpetro. Yet, proceeds an examination of the transportation activity under a constitutional optics, based on the EC 9/95; a legal optic, from the Petroleum Law (Law 9478/97) and some other legal documents related to the theme. Finally, presents the importance that the Law of Natural Gas (Law 11909/09) brought for that activity, by making possible that the natural gas transportation can also be effectuated through the Concession.

  1. Three-dimensional calculations of charge neutralization by neutral gas release

    International Nuclear Information System (INIS)

    Mandell, M.J.; Jongeward, G.A.; Katz, I.

    1993-01-01

    There have been numerous observations of high rocket or spacecraft potentials, both positive and negative, and both naturally and artificially induced, being neutralized during thruster firings. Two current studies, CHARGE-2B (positive polarity) and SPEAR3 (negative polarity), attempt a more systematic exploration of this phenomenon. The authors present here calculations performed in support of the SPEAR-3 program. (1) Conventional phenomenology of breakdown is applied to the three-dimensional system formed by the electrostatic potential and plume density fields. Using real cross sections, they calculate the paths along which the nozzle plume can support breakdown. This leads to a recommendation that the higher flow rate on SPEAR-3 be 2 g/s of argon, equal to the CHARGE-2B flow rate. (2) In a laboratory chamber, conditions (pressure of ∼ 2 x 10 - 5 torr) favor breakdown of the positive (electron-collecting) sheath for SPEAR-3 geometry. Three-dimensional calculations illustrate the evolution of the space charge and potential structure during the breakdown process. These calculations demonstrate the ability to apply accepted phenomenology to real systems with three dimensional electrostatic potential fields, space charge fields, and neutral density fields, including magnetic field effects and real cross-section data

  2. Investigation of the Neutral Gas Pressure Effect on the Metal Resistive Bolometer

    International Nuclear Information System (INIS)

    Zhang, D.; Giannone, L.; Piechotka, M.; Windisch, T.; Klinger, T.; Grulke, O.; Stark, A.

    2008-01-01

    The bolometer system planned for W7-X consists mainly of metal (Au) resistive detector arrays. All the detectors are exposed to neutral gas environment. The thin bolometer foil used for detecting the radiated power loss may be sensitive to the neutral gas pressure due to the strain gauge effect. Recently, a prototype of this kind of bolometer camera consisting of 12 channels has been installed on the cylindrical plasma device VINETA in order to investigate the influences of the neutral gas pressure on the bolometer signals. Experiments are carried out for Ar-discharges under different gas pressure conditions. It is found that the pressure effect of the neutral gas can make considerable contributions, thus inducing non-negligible errors of the results in most of the investigated cases. Using the VINETA plasmas (Ar, T e e -19 m -3 ) as examples, the paper demonstrates and discusses how to minimize the neutral gas effects, especially in the data analysis process. The radiated power and the radiation intensity profile obtained in helicon discharges are presented

  3. Investigation of the Neutral Gas Pressure Effect on the Metal Resistive Bolometer

    Science.gov (United States)

    Zhang, D.; Giannone, L.; Grulke, O.; Piechotka, M.; Windisch, T.; Stark, A.; Klinger, T.

    2008-03-01

    The bolometer system planned for W7-X consists mainly of metal (Au) resistive detector arrays. All the detectors are exposed to neutral gas environment. The thin bolometer foil used for detecting the radiated power loss may be sensitive to the neutral gas pressure due to the strain gauge effect. Recently, a prototype of this kind of bolometer camera consisting of 12 channels has been installed on the cylindrical plasma device VINETA in order to investigate the influences of the neutral gas pressure on the bolometer signals. Experiments are carried out for Ar-discharges under different gas pressure conditions. It is found that the pressure effect of the neutral gas can make considerable contributions, thus inducing non-negligible errors of the results in most of the investigated cases. Using the VINETA plasmas (Ar, Te<10 eV, ne<10-19 m-3) as examples, the paper demonstrates and discusses how to minimize the neutral gas effects, especially in the data analysis process. The radiated power and the radiation intensity profile obtained in helicon discharges are presented.

  4. Transport of liquefied natural gas by tankers

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, Y N; Mkrtychan, Y S; Tregubov, I A; Belyaev, I G

    1979-03-01

    A survey conducted by the USSR's VNIIgaz indicates that the number of LNG tankers in use and under construction presently exceeds 100, ranging in capacity from 600 to 130,000 m/sup 3/. The annual volume of LNG transported by tanker is expected to reach 50 to 60 billion m/sup 3/ by 1980. VNIIgaz examines (1) the design of present tankers, (2) the differences in gas-transport temperature, insulation, and engines, (3) transport recommendations of various LNG-tanker companies around the world, (4) parameters of some types of commercial diesel engines used for tanker propulsion (fueled by gas and/or heavy fuel oil), (5) relative advantages and disadvantages of diesel engines, and (6) the control system for the main gas diesel of an LNG tanker.

  5. The transport system for natural gas

    International Nuclear Information System (INIS)

    Bjoerndalen, Joergen; Nese, Gjermund

    2003-01-01

    In 2002, the actors on the Norwegian shelf in cooperation with the authorities established a new regime for sale and transport of gas. This article deals with some issues of interest relating to this new regime. The transport system for natural gas shows clear signs of being a natural monopoly, which makes it difficult to use the system efficiently. Two main problems of the current way of organizing are pointed out: (1) lack of price and market signals in capacity allocation and (2) unclear incentive effects. The article indicates a possible solution based on the form of organization that is used in the power market

  6. Transportation charges in the gas industry

    International Nuclear Information System (INIS)

    Price, C.

    1994-01-01

    British Gas was privatized in 1986, a monopoly with no direct competition and only very light regulation of the tariff market. The regulator had an obligation to enable competition to develop in the unregulated, large-quantity, contract market. Competitors required access to the BG-owned transportation network. The government has recently rejected the recommendation of divestiture of the supply business, but has accelerated the advent of competition to the domestic market. This paper considers the role of BG's transport charges in these developments, using its past behaviour as a guide, and identifying the issues for future regulation and development of the gas market. (Author)

  7. Macroscopic cross sections for analyzing the transport of neutral particles in plasmas

    International Nuclear Information System (INIS)

    Suzuki, Tadakazu; Taji, Yuukichi; Nakahara, Yasuaki

    1975-05-01

    Algorithms have been developed for calculating the ionization and charge exchange cross sections required for analyzing the neutral transport in plasmas. In our algorithms, the integration of the expression for reaction rate of neutrals with plasmas is performed by expanding the integrand with the use of polynomials. At present, multi-energy-group sets of the cross sections depending on plasma temperature and energy of neutrals can be prepared by means of Maxwellian averages over energy. Calculational results are printed out in the FIDO format. Some numerical examples are given for several forms of spatial distributions assumed for the plasma ion temperature and source neutral energy. (auth.)

  8. Injection of a relativistic electron beam into neutral hydrogen gas

    International Nuclear Information System (INIS)

    de Haan, P.H.; Janssen, G.C.A.M.; Hopman, H.J.; Granneman, E.H.A.

    1982-01-01

    The injection of a relativistic electron beam (0.8 MeV, 6 kA, 150 nsec) into hydrogen gas of 190 Pa pressure results in a plasma with density n/sub e/approx. =10 20 m -3 and temperature kT/sub e/< or approx. =kT/sub i/approx. =3.5 eV. The results of the measurements show good agreement with computations based on a model combining gas ionization and turbulent plasma heating. It is found that a quasistationary state exists in which the energy lost by the beam (about 6% of the total kinetic energy of the beam) is partly used to further ionize and dissociate the gas and for the other part is lost as line radiation

  9. Gas transportation issues in the WCSB

    International Nuclear Information System (INIS)

    Turner, M.

    1998-01-01

    This paper addressed the issue of the competitiveness of the Western Canadian Sedimentary Basin (WCSB), concentrating on transportation issues. Various related issues such as natural gas pricing dynamics, price convergence in late 1998, projected gas revenues, issues of supply and demand, reserves inventory, the worrisome rate of decline in well productivity, deliverability and drilling, all received attention. Despite the gloomy picture, the general conclusion was that industry activity in the Basin will need to increase as the growth of the WCSB will be driven by rising North American demand. A profile of Nova Gas Transmission Ltd. was also presented. 1 tab., 13 figs

  10. [Natural gas rate design and transportation issues

    International Nuclear Information System (INIS)

    Howard, G.S.

    1992-01-01

    This paper is presented from an industrial user viewpoint with regards to natural gas distribution and pricing. The author reviews the problems with rate structures at local distributing companies and gas utility companies which resort to charging high prices to industrial users while subsidizing residential users. He goes on then to discuss the lack of innovation amount LDCs to meet the needs of the industrial sector. Secondly it analyses the regulation and price structure of the pipeline industry which drastically affects all gas prices. The paper specifically discusses 'equivalent margin rates' which are being used by many states to control transportation rates. The author feels that these margin rates are inappropriate in that it transfers much of the LDC's exploration and development costs to the pipeline company which transfers it on to the consumer. He feels that the transportation rates should exclude all costs that are clearly not incurred by an LDC to provide transportation service. The paper concludes with recommendations to regulators regarding the need for regulatory reform of deregulation of the gas industry with regards to profit-taking and the transportation industry with regards to developing capacity assignment programs

  11. Positron transport: The plasma-gas interface

    International Nuclear Information System (INIS)

    Marler, J. P.; Petrovic, Z. Lj.; Bankovic, A.; Dujko, S.; Suvakov, M.; Malovic, G.; Buckman, S. J.

    2009-01-01

    Motivated by an increasing number of applications, new techniques in the analysis of electron transport have been developed over the past 30 years or so, but similar methods had yet to be applied to positrons. Recently, an in-depth look at positron transport in pure argon gas has been performed using a recently established comprehensive set of cross sections and well-established Monte Carlo simulations. The key novelty as compared to electron transport is the effect of positronium formation which changes the number of particles and has a strong energy dependence. This coupled with spatial separation by energy of the positron swarm leads to counterintuitive behavior of some of the transport coefficients. Finally new results in how the presence of an applied magnetic field affects the transport coefficients are presented.

  12. Gas injection in EBT-S for assessment of particle loading effects of neutral beam injection

    International Nuclear Information System (INIS)

    Carpenter, K.H.; Glowienka, J.C.

    1979-01-01

    Experiments have begun to examine the physics of neutral beam injection on EBT-S. Preliminary experiments have been limited to a calibrated gas puffing experiment which simulates the effects of a pulsed beam with zero energy. These experiments begin to address some of the compatibility problems that exist for future beam heating experiments on EBT devices. In particular, neutral beams are to be a significant part of the planned EBT-II experiment which is designed to demonstrate steady-state, reactor-like conditions with both electron cyclotron heating and neutral beam heating

  13. Operation of a TFTR ion source with a ground potential gas feed into the neutralizer

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Dudek, L.E.; Grisham, L.R.; Newman, R.A.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A.; Williams, M.D.; Wright, K.E.

    1991-01-01

    TFTR long pulse ion sources have been operated with gas fed only into the neutralizer. Gas for the plasma generator entered through the accelerator rather than directly into the arc chamber. This modification has been proposed for tritium beam operation to locate control electronics at ground potential and to simplify tritium plumbing. Source operation with this configuration and with the nominal gas system that feeds gas into both the ion source and the center of the neutralizer are compared. Comparison is based upon accelerator grid currents, beam composition, and neutral power delivered to the calorimeter. Charge exchange in the accelerator can be a significant loss mechanism in both systems at high throughput. A suitable operating point with the proposed system was found that requires 30% less gas than used presently. The extracted D + , D + 2 , and D + 3 fractions of the beam were found to be a function of the gas throughput; at similar throughputs, the two gas feed systems produced similar extracted ion fractions. Operation at the proposed gas efficient point results in a small reduction (relative to the old high throughput mode) in the extracted D + fraction of the beam from 77% to 71%, with concomitant changes in the D + 2 fraction from 18% to 26%, and 6% to 3% for D + 3 . The injected power is unchanged, ∼2.2 MW at 95 kV

  14. Improved alternating gradient transport and focusing of neutral molecules

    International Nuclear Information System (INIS)

    Kalnins, Juris; Lambertson, Glen; Gould, Harvey

    2001-01-01

    Polar molecules, in strong-field seeking states, can be transported and focused by an alternating sequence of electric field gradients that focus in one transverse direction while defocusing in the other. We show by calculation and numerical simulation, how one may greatly improve the alternating gradient transport and focusing of molecules. We use a new optimized multipole lens design, a FODO lattice beam transport line, and lenses to match the beam transport line to the beam source and the final focus. We derive analytic expressions for the potentials, fields, and gradients that may be used to design these lenses. We describe a simple lens optimization procedure and derive the equations of motion for tracking molecules through a beam transport line. As an example, we model a straight beamline that transports a 560 m/s jet-source beam of methyl fluoride molecules 15 m from its source and focuses it to 2 mm diameter. We calculate the beam transport line acceptance and transmission, for a beam with velocity spread, and estimate the transmitted intensity for specified source conditions. Possible applications are discussed

  15. Electron emission in the Auger neutralization of a spin-polarized He+ ion embedded in a free electron gas

    International Nuclear Information System (INIS)

    Juaristi, J.I.; Alducin, M.; Diez Muino, R.; Roesler, M.

    2005-01-01

    Results are presented for the energy distribution and spin polarization of the electrons excited during the Auger neutralization of a spin polarized He + ion embedded in a paramagnetic free electron gas. The screening of the He + ion is calculated using density functional theory within the local spin density approximation. The Auger rates, the energy distribution and the spin polarization of the excited electrons are obtained using the Fermi golden rule. The transport of the electrons is calculated within the Boltzmann transport equation formalism. The spin-polarization of the initially excited electrons is very high (>70%) and parallel to that of the electron bound to the He + ion. Nevertheless, the emitted electrons show a much lower degree of polarization, mainly in the low energy range, due to the creation of the unpolarized cascade of secondaries in the transport process

  16. Coupled plasma-neutral transport model for the scrape-off region

    International Nuclear Information System (INIS)

    Galambos, J.D.; Peng, Y.K.M.; Heifetz, D.

    1985-03-01

    Analysis of the scrape-off region requires treatment of the plasma transport along and across the field lines and inclusion of the neutral transport effects. A method for modeling the scrape-off region that is presented here uses separate models for each of these aspects that are coupled together through an iteration procedure that requires only minimal numerical effort. The method is applied here to estimate the neutral pumping rates in the pump-limiter and divertor options for a proposed deuterium-tritium (D-T) ignition experiment. High neutral recycling in the vicinity of the neutralizer plate dramatically affects pumping rates for both the pump-limiter and divertor. In both cases, the plasma flow into the channel surrounding the neutralizer plate is greatly reduced by the neutral recycling. The fraction of this flow that is pumped can be large (> 50%), but in general it is dependent on the particular geometry and plasma conditions. It is estimated that pumping speeds approximately greater than 10 5 L/s are adequate for the exhaust requirements in the pump-limiter and the divertor cases. Also, high neutral recycling on the front surface of the limiter tends to increase the neutral pumping rate

  17. DANTSYS: A diffusion accelerated neutral particle transport code system

    International Nuclear Information System (INIS)

    Alcouffe, R.E.; Baker, R.S.; Brinkley, F.W.; Marr, D.R.; O'Dell, R.D.; Walters, W.F.

    1995-06-01

    The DANTSYS code package includes the following transport codes: ONEDANT, TWODANT, TWODANT/GQ, TWOHEX, and THREEDANT. The DANTSYS code package is a modular computer program package designed to solve the time-independent, multigroup discrete ordinates form of the boltzmann transport equation in several different geometries. The modular construction of the package separates the input processing, the transport equation solving, and the post processing (or edit) functions into distinct code modules: the Input Module, one or more Solver Modules, and the Edit Module, respectively. The Input and Edit Modules are very general in nature and are common to all the Solver Modules. The ONEDANT Solver Module contains a one-dimensional (slab, cylinder, and sphere), time-independent transport equation solver using the standard diamond-differencing method for space/angle discretization. Also included in the package are solver Modules named TWODANT, TWODANT/GQ, THREEDANT, and TWOHEX. The TWODANT Solver Module solves the time-independent two-dimensional transport equation using the diamond-differencing method for space/angle discretization. The authors have also introduced an adaptive weighted diamond differencing (AWDD) method for the spatial and angular discretization into TWODANT as an option. The TWOHEX Solver Module solves the time-independent two-dimensional transport equation on an equilateral triangle spatial mesh. The THREEDANT Solver Module solves the time independent, three-dimensional transport equation for XYZ and RZΘ symmetries using both diamond differencing with set-to-zero fixup and the AWDD method. The TWODANT/GQ Solver Module solves the 2-D transport equation in XY and RZ symmetries using a spatial mesh of arbitrary quadrilaterals. The spatial differencing method is based upon the diamond differencing method with set-to-zero fixup with changes to accommodate the generalized spatial meshing

  18. DANTSYS: A diffusion accelerated neutral particle transport code system

    Energy Technology Data Exchange (ETDEWEB)

    Alcouffe, R.E.; Baker, R.S.; Brinkley, F.W.; Marr, D.R.; O`Dell, R.D.; Walters, W.F.

    1995-06-01

    The DANTSYS code package includes the following transport codes: ONEDANT, TWODANT, TWODANT/GQ, TWOHEX, and THREEDANT. The DANTSYS code package is a modular computer program package designed to solve the time-independent, multigroup discrete ordinates form of the boltzmann transport equation in several different geometries. The modular construction of the package separates the input processing, the transport equation solving, and the post processing (or edit) functions into distinct code modules: the Input Module, one or more Solver Modules, and the Edit Module, respectively. The Input and Edit Modules are very general in nature and are common to all the Solver Modules. The ONEDANT Solver Module contains a one-dimensional (slab, cylinder, and sphere), time-independent transport equation solver using the standard diamond-differencing method for space/angle discretization. Also included in the package are solver Modules named TWODANT, TWODANT/GQ, THREEDANT, and TWOHEX. The TWODANT Solver Module solves the time-independent two-dimensional transport equation using the diamond-differencing method for space/angle discretization. The authors have also introduced an adaptive weighted diamond differencing (AWDD) method for the spatial and angular discretization into TWODANT as an option. The TWOHEX Solver Module solves the time-independent two-dimensional transport equation on an equilateral triangle spatial mesh. The THREEDANT Solver Module solves the time independent, three-dimensional transport equation for XYZ and RZ{Theta} symmetries using both diamond differencing with set-to-zero fixup and the AWDD method. The TWODANT/GQ Solver Module solves the 2-D transport equation in XY and RZ symmetries using a spatial mesh of arbitrary quadrilaterals. The spatial differencing method is based upon the diamond differencing method with set-to-zero fixup with changes to accommodate the generalized spatial meshing.

  19. Alfalfa discovery of the nearby gas-rich dwarf galaxy LEO P. V. Neutral gas dynamics and kinematics

    International Nuclear Information System (INIS)

    Bernstein-Cooper, Elijah Z.; Pardy, Stephen A.; Cannon, John M.

    2014-01-01

    We present new H I spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our H I images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The H I morphology is slightly elongated along the optical major axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V c =15 ± 5 km s –1 . Within the H I radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is ≳15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature components in the neutral ISM of Leo P; the cold and warm components have characteristic velocity widths of 4.2 ± 0.9 km s –1 and 10.1 ± 1.2 km s –1 , corresponding to kinetic temperature upper limits of ∼1100 K and ∼6200 K, respectively. The cold H I component is unresolved at a physical resolution of 200 pc. The highest H I surface densities are observed in close physical proximity to the single H II region. A comparison of the neutral gas properties of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P has the lowest neutral gas mass of any known XMD, and that the dynamical mass of Leo P is more than two orders of magnitude smaller than any known XMD with comparable metallicity.

  20. Electrolyte transport in neutral polymer gels embedded with charged inclusions

    Science.gov (United States)

    Hill, Reghan

    2005-11-01

    Ion permeable membranes are the basis of a variety of molecular separation technologies, including ion exchange, gel electrophoresis and dialysis. This work presents a theoretical model of electrolyte transport in membranes comprised of a continuous polymer gel embedded with charged spherical inclusions, e.g., biological cells and synthetic colloids. The microstructure mimics immobilized cell cultures, where electric fields have been used to promote nutrient transport. Because several important characteristics can, in principle, be carefully controlled, the theory provides a quantitative framework to help tailor the bulk properties for enhanced molecular transport, microfluidic pumping, and physicochemical sensing applications. This talk focuses on the electroosmotic flow driven by weak electric fields and electrolyte concentration gradients. Also of importance is the influence of charge on the effective ion diffusion coefficients, bulk electrical conductivity, and membrane diffusion potential.

  1. The Random Ray Method for neutral particle transport

    Energy Technology Data Exchange (ETDEWEB)

    Tramm, John R., E-mail: jtramm@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science Engineering, 77 Massachusetts Avenue, 24-107, Cambridge, MA 02139 (United States); Argonne National Laboratory, Mathematics and Computer Science Department 9700 S Cass Ave, Argonne, IL 60439 (United States); Smith, Kord S., E-mail: kord@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science Engineering, 77 Massachusetts Avenue, 24-107, Cambridge, MA 02139 (United States); Forget, Benoit, E-mail: bforget@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science Engineering, 77 Massachusetts Avenue, 24-107, Cambridge, MA 02139 (United States); Siegel, Andrew R., E-mail: siegela@mcs.anl.gov [Argonne National Laboratory, Mathematics and Computer Science Department 9700 S Cass Ave, Argonne, IL 60439 (United States)

    2017-08-01

    A new approach to solving partial differential equations (PDEs) based on the method of characteristics (MOC) is presented. The Random Ray Method (TRRM) uses a stochastic rather than deterministic discretization of characteristic tracks to integrate the phase space of a problem. TRRM is potentially applicable in a number of transport simulation fields where long characteristic methods are used, such as neutron transport and gamma ray transport in reactor physics as well as radiative transfer in astrophysics. In this study, TRRM is developed and then tested on a series of exemplar reactor physics benchmark problems. The results show extreme improvements in memory efficiency compared to deterministic MOC methods, while also reducing algorithmic complexity, allowing for a sparser computational grid to be used while maintaining accuracy.

  2. The Random Ray Method for neutral particle transport

    International Nuclear Information System (INIS)

    Tramm, John R.; Smith, Kord S.; Forget, Benoit; Siegel, Andrew R.

    2017-01-01

    A new approach to solving partial differential equations (PDEs) based on the method of characteristics (MOC) is presented. The Random Ray Method (TRRM) uses a stochastic rather than deterministic discretization of characteristic tracks to integrate the phase space of a problem. TRRM is potentially applicable in a number of transport simulation fields where long characteristic methods are used, such as neutron transport and gamma ray transport in reactor physics as well as radiative transfer in astrophysics. In this study, TRRM is developed and then tested on a series of exemplar reactor physics benchmark problems. The results show extreme improvements in memory efficiency compared to deterministic MOC methods, while also reducing algorithmic complexity, allowing for a sparser computational grid to be used while maintaining accuracy.

  3. Integrated transport code system for a multicomponent plasma in a gas dynamic trap

    International Nuclear Information System (INIS)

    Anikeev, A.V.; Karpushov, A.N.; Noak, K.; Strogalova, S.L.

    2000-01-01

    This report is focused on the development of the theoretical and numerical models of multicomponent high-β plasma confinement and transport in the gas-dynamic trap (GDT). In order to simulate the plasma behavior in the GDT as well as that in the GDT-based neutron source the Integrated Transport Code System is developed from existing stand-alone codes calculating the target plasma, the fast ions and the neutral gas in the GDT. The code system considers the full dependence of the transport phenomena on space, time, energy and angle variables as well as the interactions between the particle fields [ru

  4. Serotonin transporter genotype (5-HTTLPR): effects of neutral and undefined conditions on amygdala activation.

    Science.gov (United States)

    Heinz, Andreas; Smolka, Michael N; Braus, Dieter F; Wrase, Jana; Beck, Anne; Flor, Herta; Mann, Karl; Schumann, Gunter; Büchel, Christian; Hariri, Ahmad R; Weinberger, Daniel R

    2007-04-15

    A polymorphism of the human serotonin transporter gene (SCL6A4) has been associated with serotonin transporter expression and with processing of aversive stimuli in the amygdala. Functional imaging studies show that during the presentation of aversive versus neutral cues, healthy carriers of the short (s) allele showed stronger amygdala activation than long (l) carriers. However, a recent report suggested that this interaction is driven by amygdala deactivation during presentation of neutral stimuli in s carriers. Functional MRI was used to assess amygdala activation during the presentation of a fixation cross or affectively aversive or neutral visual stimuli in 29 healthy men. Amygdala activation was increased in s carriers during undefined states such as the presentation of a fixation cross compared with emotionally neutral conditions. This finding suggests that s carriers show stronger amygdala reactivity to stimuli and contexts that are relatively uncertain, which we propose are stressful.

  5. On the relation between plasma and neutral gas profiles in a cold gas-blanket system

    International Nuclear Information System (INIS)

    Bures, M.

    1981-01-01

    A solution for the neutral density profile using the measured plasma density and temperature gradients is presented. The fluid model is used. It is found that the penetration length for neutrals is underestimated in the situation where the integrated profiles are used. The ionization rate need not be inferred in the present calculation, because the ionization of neutrals diffusing into the plasma is implicitly included in measured profiles. This calculation is advantageous in the low temperature range where the ionization rate is a strongly varying function of temperature. Finally the presented solution indicates that the temperature gradient plays the essential role in the determination of the neutral density profile. (Auth.)

  6. Ben Macdhui High Altitude Trace Gas and Aerosol Transport Experiment

    CSIR Research Space (South Africa)

    Piketh, SJ

    1999-01-01

    Full Text Available The Ben Macdhui High Altitude Aerosol and Trace Gas Transport Experiment (BHATTEX) was started to characterize the nature and magnitude of atmospheric, aerosol and trace gas transport paths recirculation over and exiting from southern Africa...

  7. Adaptive tree multigrids and simplified spherical harmonics approximation in deterministic neutral and charged particle transport

    International Nuclear Information System (INIS)

    Kotiluoto, P.

    2007-05-01

    A new deterministic three-dimensional neutral and charged particle transport code, MultiTrans, has been developed. In the novel approach, the adaptive tree multigrid technique is used in conjunction with simplified spherical harmonics approximation of the Boltzmann transport equation. The development of the new radiation transport code started in the framework of the Finnish boron neutron capture therapy (BNCT) project. Since the application of the MultiTrans code to BNCT dose planning problems, the testing and development of the MultiTrans code has continued in conventional radiotherapy and reactor physics applications. In this thesis, an overview of different numerical radiation transport methods is first given. Special features of the simplified spherical harmonics method and the adaptive tree multigrid technique are then reviewed. The usefulness of the new MultiTrans code has been indicated by verifying and validating the code performance for different types of neutral and charged particle transport problems, reported in separate publications. (orig.)

  8. Gas utilization in the Tokamak Fusion Test Reactor neutral beam injectors

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Gammel, G.M.; Kugel, H.W.; Grisham, L.R.; Stevenson, T.N.; von Halle, A.; Williams, M.D.; Jones, T.T.C.

    1989-01-01

    Measurements of gas utilization were performed using hydrogen and deuterium beams in the Tokamak Fusion Test Reactor (TFTR) neutral beam test beamline to study the feasibility of operating tritium beams with existing ion sources under conditions of minimal tritium consumption. (i) It was found that the fraction of gas molecules introduced into the TFTR long-pulse ion sources that are converted to extracted ions (i.e., the ion source gas efficiency) was higher than with previous short-pulse sources. Gas efficiencies were studied over the range 33%--55%, and its effect on neutralization of the extracted ions was studied. At the high end of the gas efficiency range, the neutral fraction of the beam fell below that predicted from room-temperature molecular gas flow (similar to observations at the Joint European Torus). (ii) Beam isotope change studies were performed. No extracted hydrogen ions were observed in the first deuterium beam following a working gas change from H 2 to D 2 . There was no arc conditioning or gas injection preceding the first beam extraction attempt. (iii) Experiments were also performed to determine the reliability of ion source operation during the long waiting periods between pulses that are anticipated during tritium operation. It was found that an ion source conditioned to 120 kV could produce a clean beam pulse after a waiting period of 14 h by preceding the beam extraction with several acceleration voltage/filament warm-up pulses. It can be concluded that the operation of up to six ion sources on tritium gas should be compatible with on-site inventory restrictions established for D--T, Q = 1 experiments on TFTR

  9. Gas fuels for the transport sector; Denmark; Gas til transportsektoren

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    Recent analyses suggest that especially biogas, but also natural gas in macroeconomic terms will be attractive propellants, including for heavy transport. To implement a Danish expansion of gas infrastructure for transportation, the report recommends the following essential elements: 1) A Danish rollout should be closely linked to contracts with fleet owners with heavy vehicles / taxis / vans and the like, thus ensuring high utilization of filling stations; 2) About 10 larger, flexible CNG filling stations set up at major fleet owners is estimated as sufficient for an initial deployment phase, strategically distributed in and around Copenhagen, the major cities and along the main road network from Sweden to Germany; 3) A certain time-limited funding for the construction of infrastructure is likely to cause a rapid spread, if desired, and if other business conditions are in place; 4) There is a need for adjustment of tax terms - the rules for green taxes should be adjusted, and it should be considered to lower the taxes on CNG and biogas; 5) Natural gas mixed with biogas should be an integral element of a comprehensive strategy to ensure maximum CO{sub 2} displacement. (LN)

  10. Gas Transport Services. West European Gas Transmission Tariff Comparisons

    International Nuclear Information System (INIS)

    2006-07-01

    Since 1999, the Dutch gas transmission company, Gastransport Services (GTS), has commissioned an independent consultant to prepare reports comparing gas transportation tariffs across Western Europe on an annual basis. This report describes the tariffs in force at 1 February 2006. The previous report was published in May 2005, and reported on the tariffs which were in force at 1 January 2005. Since then several companies have published revised carriage arrangements, or have adjusted their tariffs (e.g. to reflect inflation, or for other reasons). In this report we compare the GTS tariff with the transportation tariffs in eleven other countries: Austria, Belgium, Denmark, France, Germany, Ireland, Italy, Luxembourg, Spain, Sweden, and the United Kingdom. This means that all West European countries with Third Party Access to gas transmission systems (except Finland) are covered in this report. In this main part of the report, we concentrate on showing charts which illustrate the comparisons of tariffs, at various distances, volumes and load factors. This gives an overall picture of the tariffs offered by each company, rather than concentrating on particular cases. The detailed calculations for each of the 45 cases are shown in the Appendix to this report, and the conclusions from the cases are shown in a colour-coded chart in the Summary and Conclusions.

  11. Spatial profiling of ion and neutral excitation in noble gas electron cyclotron resonance plasmas

    International Nuclear Information System (INIS)

    Rhoades, R.L.; Gorbatkin, S.M.

    1994-01-01

    Optical emission from neutrals and ions of several noble gases has been profiled in an electron cyclotron resonance plasma system. In argon plasmas with a net microwave power of 750 W, the neutral (696.5-nm) and ion (488-nm) emission profiles are slightly center peaked at 0.32 mTorr and gradually shift to a hollow appearance at 2.5 mTorr. Neon profiles show a similar trend from 2.5 to 10.0 mTorr. For the noble gases, transition pressure scales with the ionization potential of the gas, which is consistent with neutral depletion. Studies of noble gas mixtures, however, indicate that neutral depletion is not always dominant in the formation of hollow profiles. For Kr/Ar, Ar/Ne, and Ne/He plasmas, the majority gas tends to set the overall shape of the profile at any given pressure. For the conditions of the current system, plasma density appears to be more dominant than electron temperature in the formation of hollow profiles. The general method described is also a straightforward, inexpensive technique for measuring the spatial distribution of power deposited in plasmas, particularly where absolute scale can be calibrated by some other means

  12. Alternative ways to transport natural gas; Transporte alternativo de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Moura, N.R.; Campos, F.B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    The Brazilian energy matrix has been showing a huge increase in the demand of natural gas due mainly to industries and power plants. Today the Brazilian gas market is supplied with gas produced by PETROBRAS and imported from Bolivia. To increase the Brazilian gas supply, on the short and middle term, PETROBRAS will import LNG (liquefied natural gas) and exploit the new offshore fields discovered on the pre-salt area. The only proven technology available today to bring this offshore gas to the market is the pipeline, but its costs for the pre-salt area are high enough to keep the solution economically attractive. So, PETROBRAS are evaluating and developing alternative ways to transport offshore gas, such as LNG, CNG (Compressed Natural Gas), GTS (Gas-to-Solids or Natural Gas Hydrates) and ANG (Adsorbed Natural Gas). Using information available in the literature, this paper analyses the main concepts of CNG and LNG floating unities. This paper also presents the PETROBRAS R and D results on ANG and GTS aiming at offshore application. (author)

  13. Aurora T: a Monte Carlo code for transportation of neutral atoms in a toroidal plasma

    International Nuclear Information System (INIS)

    Bignami, A.; Chiorrini, R.

    1982-01-01

    This paper contains a short description of Aurora code. This code have been developed at Princeton with Monte Carlo method for calculating neutral gas in cylindrical plasma. In this work subroutines such one can take in account toroidal geometry are developed

  14. Transport coefficients of a dissociating gas

    International Nuclear Information System (INIS)

    Lebed', I.V.

    1987-01-01

    The calculation of the transport coefficients of a dissociating gas involves fundamental difficulties which arise when the internal degrees of freedom of the molecules are taken strictly into account. In practical calculations extensive use is made of the approximation in the context of which the dependence of a diffusion velocity of the molecule on its internal state is totally neglected. In this case the expressions for the stress tensor and the diffusion velocities coincide with the corresponding expressions for a mixture of structureless particles; in the expression for the heat flux the diffusion transport of internal energy is taken only approximately into account. Here, analytic expressions for the diffusion velocities, heat flux and stress tensor are obtained without introducing simplifying assumptions. The calculation method is based on an approximate method of calculating the transport coefficients of a multicomponent mixture of structureless particles. The relations obtained are analyzed and compared with the existing results; their accuracy is estimated. A closed system of equations of gas dynamics is presented for a number of cases of practical importance

  15. Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals.

    Science.gov (United States)

    Sato, Katsufumi; Aoki, Kagari; Watanabe, Yuuki Y; Miller, Patrick J O

    2013-01-01

    Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.

  16. Natural gas and renewable methane for powertrains future strategies for a climate-neutral mobility

    CERN Document Server

    2016-01-01

    This book focuses on natural gas and synthetic methane as contemporary and future energy sources. Following a historical overview, physical and chemical properties, occurrence, extraction, transportation and storage of natural gas are discussed. Sustainable production of natural gas and methane as well as production and storage of synthetic methane are scrutinized next. A substantial part of the book addresses construction of vehicles for natural and synthetic methane as well as large engines for industrial and maritime use. The last chapters present some perspectives on further uses of renewable liquid fuels as well as natural gas for industrial engines and gas power plants.

  17. Application of diffusion theory to neutral atom transport in fusion plasmas

    International Nuclear Information System (INIS)

    Hasan, M.Z.; Conn, R.W.; Pomraning, G.C.

    1987-01-01

    It is found that the energy dependent diffusion theory provides excellent accuracy in the modelling of transport of neutral atoms in fusion plasmas. Two reasons in particular explain the good accuracy. First, while the plasma is optically thick for low energy neutrals, it is optically thin for high energy neutrals and the diffusion theory with Marshak boundary conditions gives accurate results for an optically thin medium, even for small values of c, the ratio of the scattering cross-section to the total cross-section. Second, the effective value of c at low energy is very close to 1 because of the downscattering via collisions of high energy neutrals. The first reason is proven computationally and theoretically by solving the transport equation in a power series in c and solving the diffusion equation with 'general' Marshak boundary conditions. The second reason is established numerically by comparing the results from a one-dimensional, general geometry, multigroup diffusion theory code, written for this purpose, with the results obtained using the transport code ANISN. Earlier studies comparing one-speed diffusion and transport theory indicated that the diffusion theory would be inaccurate. A detailed analysis shows that this conclusion is limited to a very specific case. Surprisingly, for a very wide range of conditions and when energy dependence is included, the diffusion theory is highly accurate. (author)

  18. The peritoneal transport of serum proteins and neutral dextran in CAPD patients

    NARCIS (Netherlands)

    Krediet, R. T.; Koomen, G. C.; Koopman, M. G.; Hoek, F. J.; Struijk, D. G.; Boeschoten, E. W.; Arisz, L.

    1989-01-01

    The peritoneal transport of five serum proteins and intravenously-administered neutral dextran was studied in 13 CAPD patients. In all patients a study was done three hours after the administration of dextran. In nine the study was repeated after 14 hours, and in six also after 38 hours. Using gel

  19. Simulation of neutral gas flow in a tokamak divertor using the Direct Simulation Monte Carlo method

    International Nuclear Information System (INIS)

    Gleason-González, Cristian; Varoutis, Stylianos; Hauer, Volker; Day, Christian

    2014-01-01

    Highlights: • Subdivertor gas flows calculations in tokamaks by coupling the B2-EIRENE and DSMC method. • The results include pressure, temperature, bulk velocity and particle fluxes in the subdivertor. • Gas recirculation effect towards the plasma chamber through the vertical targets is found. • Comparison between DSMC and the ITERVAC code reveals a very good agreement. - Abstract: This paper presents a new innovative scientific and engineering approach for describing sub-divertor gas flows of fusion devices by coupling the B2-EIRENE (SOLPS) code and the Direct Simulation Monte Carlo (DSMC) method. The present study exemplifies this with a computational investigation of neutral gas flow in the ITER's sub-divertor region. The numerical results include the flow fields and contours of the overall quantities of practical interest such as the pressure, the temperature and the bulk velocity assuming helium as model gas. Moreover, the study unravels the gas recirculation effect located behind the vertical targets, viz. neutral particles flowing towards the plasma chamber. Comparison between calculations performed by the DSMC method and the ITERVAC code reveals a very good agreement along the main sub-divertor ducts

  20. Alfalfa discovery of the nearby gas-rich dwarf galaxy LEO P. V. Neutral gas dynamics and kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein-Cooper, Elijah Z.; Pardy, Stephen A. [Department of Astronomy, University of Wisconsin, 475 N Charter Street, Madison, WI 53706 (United States); Cannon, John M., E-mail: ezbc@astro.wisc.edu, E-mail: spardy@astro.wisc.edu, E-mail: jcannon@macalester.edu [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); and others

    2014-08-01

    We present new H I spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our H I images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The H I morphology is slightly elongated along the optical major axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V {sub c} =15 ± 5 km s{sup –1}. Within the H I radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is ≳15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature components in the neutral ISM of Leo P; the cold and warm components have characteristic velocity widths of 4.2 ± 0.9 km s{sup –1} and 10.1 ± 1.2 km s{sup –1}, corresponding to kinetic temperature upper limits of ∼1100 K and ∼6200 K, respectively. The cold H I component is unresolved at a physical resolution of 200 pc. The highest H I surface densities are observed in close physical proximity to the single H II region. A comparison of the neutral gas properties of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P has the lowest neutral gas mass of any known XMD, and that the dynamical mass of Leo P is more than two orders of magnitude smaller than any known XMD with comparable metallicity.

  1. Attenuation of acoustic waves through reflections at the plasma neutral gas interfaces: weakly ionised case

    International Nuclear Information System (INIS)

    Ghosal, S.K.; Sen, S.N.

    1977-01-01

    The problem of transmission of sonic waves through a weakly ionised plasma bounded in each side by a neutral gas medium has been treated by assuming the plasma to be a mixture of two intermingled fluids viz., neutral particle fluid and ion fluid in equilibrium. From a hydrodynamic analysis the wave equation for 'p', the macroscopic pressure perturbation has been obtained and it is shown that two independent wave motions, one due to the neutral particles and the other due to ions are propagated through the plasma with two different phase velocities. Assuming the usual boundary conditions at the interface, the amplitude of the transmitted wave has been calculated in case of weakly ionized plasma; the theory can be utilized for the determination of electron temperature from the measured value of attenuation if the percentage of ionization and collision cross section can be obtained independently. (author)

  2. Properties of clusters in the gas phase: V. Complexes of neutral molecules onto negative ions

    International Nuclear Information System (INIS)

    Keesee, R.G.; Lee, N.; Castleman, A.W. Jr.

    1980-01-01

    Ion--molecules association reactions of the form A - (B)/sub n1/-+B=A - (B)/sub n/ were studied over a range of temperatures in the gas phase using high pressure mass spectrometry. Enthalpy and entropy changes were determined for the stepwise clustering reactions of (1) sulfur dioxide onto Cl - , I - , and NO 2 - with n ranging from one to three or four, and onto SO 2 - and SO 3 - with n equal to one; and (2) carbon dioxide onto Cl - , I - , NO 2 - , CO 3 - , and SO 3 - with n equal to one. From these data and earlier hydration results, the order of the magnitude of the enthalpy changes on the association of the first neutral for a series of negative ions was found to parallel the gas-phase basicity of those anions. For any given ion, the relative order of the addition enthalpies among the neutrals was found to be dependent on the polarizabilities of the neutrals and on the covalency in the ion-neutral bond. Dispersion of charge via covalent bonding was found to affect significantly the succeeding clustering steps

  3. The formation of urea in space. I. Ion-molecule, neutral-neutral, and radical gas-phase reactions

    Science.gov (United States)

    Brigiano, Flavio Siro; Jeanvoine, Yannick; Largo, Antonio; Spezia, Riccardo

    2018-02-01

    Context. Many organic molecules have been observed in the interstellar medium thanks to advances in radioastronomy, and very recently the presence of urea was also suggested. While those molecules were observed, it is not clear what the mechanisms responsible to their formation are. In fact, if gas-phase reactions are responsible, they should occur through barrierless mechanisms (or with very low barriers). In the past, mechanisms for the formation of different organic molecules were studied, providing only in a few cases energetic conditions favorable to a synthesis at very low temperature. A particularly intriguing class of such molecules are those containing one N-C-O peptide bond, which could be a building block for the formation of biological molecules. Urea is a particular case because two nitrogen atoms are linked to the C-O moiety. Thus, motivated also by the recent tentative observation of urea, we have considered the synthetic pathways responsible to its formation. Aims: We have studied the possibility of forming urea in the gas phase via different kinds of bi-molecular reactions: ion-molecule, neutral, and radical. In particular we have focused on the activation energy of these reactions in order to find possible reactants that could be responsible for to barrierless (or very low energy) pathways. Methods: We have used very accurate, highly correlated quantum chemistry calculations to locate and characterize the reaction pathways in terms of minima and transition states connecting reactants to products. Results: Most of the reactions considered have an activation energy that is too high; but the ion-molecule reaction between NH2OHNH2OH2+ and formamide is not too high. These reactants could be responsible not only for the formation of urea but also of isocyanic acid, which is an organic molecule also observed in the interstellar medium.

  4. LIAD-fs: A novel method for studies of ultrafast processes in gas phase neutral biomolecules

    International Nuclear Information System (INIS)

    Calvert, C R; Kelly, O; Duffy, M J; Belshaw, L; King, R B; Williams, I D; Greenwood, J B

    2012-01-01

    A new experimental technique for femtosecond (fs) pulse studies of gas phase biomolecules is reported. Using Laser-Induced Acoustic Desorption (LIAD) to produce a plume of neutral molecules, a time-delayed fs pulse is employed for ionisation/fragmentation, with subsequent products extracted and mass analysed electrostatically. By varying critical laser pulse parameters, this technique can be used to implement control over molecular fragmentation for a range of small biomolecules, with specific studies of amino acids demonstrated.

  5. Synthesis of diamond-like carbon via PECD using a streaming neutral gas injection hollow cathode

    International Nuclear Information System (INIS)

    Pacho, A.; Pares, E.; Ramos, H.; Mendenilla, A.; Malapit, G.

    2009-01-01

    A streaming neutral gas injection hollow cathode system was used to deposit diamond-like carbon films via plasma enhanced chemical vapor deposition on silicon and nickel-coated silicon substrates with acetylene and hydrogen as reactant gases. Samples were characterized using SEM and Raman spectroscopy. The work presented here aims to demonstrate the capability of the system to synthesize carbonaceous films and is starting point towards work on formation of carbon nanostructures. (author)

  6. Stability aspects of plasmas penetrated by neutral gas with respect to velocity driven modes

    International Nuclear Information System (INIS)

    Ohlsson, D.

    1978-08-01

    A study of the stability properties of dense partially ionized plasmas immersed in strong magnetic fields with respect to velocity driven modes are presented. First we consider modes driven by mass motion perpendicular to the lines of force and the unperturbed density and temperature gradients. The presence of a third fluid, neutral gas, gives under certain conditions rise to unstable modes. This type of instability arises independently or whether the applied electric field transverse to the lines of force, driving the mass motion, being parallel or antiparallel to the unperturbed density and temperature gradient. The presence of neutral gas also corresponds to stabilizing effects which, in certain parameter regions, result in a quenching of this instability. It is shown that modes driven by velocity shear perpendicular to the lines of force are effectively stabilized by viscous and resistive effects. These effects are in certain parameter ranges strongly enhanced on account of plasma-neutral gas interaction effects. In collisionless plasmas, modes driven by velocity shear parallel to the lines of force are stabilized by compressibility effects parallel to the magnetic field and by finite Larmor radius effects. (author)

  7. Gas transportation tariffs in the european union market

    International Nuclear Information System (INIS)

    Bianchi, A.

    2001-01-01

    In a liberalised market, it is an indubitable competitive advantage for a firm to accede at the gas grid with a low cost. The comparison among gas transportation tariffs of 18 European gas transportation companies for a big industrial consumer, shows that Italy is in the medium-high position of the ranking [it

  8. Application of diffusion theory to neutral atom transport in fusion plasmas

    International Nuclear Information System (INIS)

    Hasan, M.Z.; Conn, R.W.; Pomraning, G.C.

    1986-05-01

    It is found that energy dependent diffusion theory provides excellent accuracy in the modelling of transport of neutral atoms in fusion plasmas. Two reasons in particular explain the good accuracy. First, while the plasma is optically thick for low energy neutrals, it is optically thin for high energy neutrals and diffusion theory with Marshak boundary conditions gives accurate results for an optically thin medium even for small values of 'c', the ratio of the scattering to the total cross section. Second, the effective value of 'c' at low energy becomes very close to one due to the down-scattering via collisions of high energy neutrals. The first reason is proven both computationally and theoretically by solving the transport equation in a power series in 'c' and the diffusion equation with 'general' Marshak boundary conditions. The second reason is established numerically by comparing the results from a one-dimensional, general geometry, multigroup diffusion theory code, written for this purpose, with the results obtained using the transport code ANISN

  9. Fast-ion transport and neutral beam current drive in ASDEX upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

    2015-01-01

    The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profiles...... during on-axis injection and outwards shifted profiles during off-axis injection. Due to this change of the fast-ion population, a clear modification of the plasma current profile is predicted but not observed by a motional Stark effect diagnostic. The fast-ion transport caused by MHD activity has been...

  10. Design and characterization of a neutralized-transport experiment for heavy-ion fusion

    Directory of Open Access Journals (Sweden)

    Enrique Henestroza

    2004-08-01

    Full Text Available In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit of the final-focus magnet system through the fusion chamber to hit spots on the target with radii of about 2 mm. For the heavy-ion-fusion power-plant scenarios presently favored in the U.S., a substantial fraction of the ion-beam space charge must be neutralized during this final transport. The most effective neutralization technique found in numerical simulations is to pass each beam through a low-density plasma after the final focusing. To provide quantitative comparisons of these theoretical predictions with experiment, the Virtual National Laboratory for Heavy Ion Fusion has completed the construction and has begun experimentation with the neutralized-transport experiment. The experiment consists of three main sections, each with its own physics issues. The injector is designed to generate a very high-brightness, space-charge-dominated potassium beam, while still allowing variable perveance by a beam aperturing technique. The magnetic-focusing section, consisting of four pulsed quadrupoles, permits the study of magnet tuning, as well as the effects of phase-space dilution due to higher-order nonlinear fields. In the final section, the converging ion beam exiting the magnetic section is transported through a drift region with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization. In this paper, we discuss the design and characterization of the three sections in detail and present initial results from the experiment.

  11. Gas-phase transport of fission products

    International Nuclear Information System (INIS)

    Tang, I.N.; Munkelwitz, H.R.

    1982-01-01

    The paper presents the results of an experimental investigation to show the importance of nuclear aerosol formation as a mechanism for semi-volatile fission product transport under certain postulated HTGR accident conditions. Simulated fission product Sr and Ba as oxides are impregnated in H451 graphite and released at elevated temperatures into a dry helium flow. In the presence of graphite, the oxides are quantitatively reduced to metals, which subsequently vaporize at temperatures much lower than required for the oxides alone to vaporize in the absence of graphite. A substantial fraction of the released material is associated with particulate matter, which is collected on filters located downstream at ambient temperatures. Increasing carrier-gas flow rate greatly enhances the extent of particulate transport. The release and transport of simulated fission product Ag as metal are also investigated. Electron microscopic examinations of the collected Sr and Ag aerosols show large agglomerates composed of primary particles roughly 0.06 to 0.08 μm in diameter

  12. Implications of the quasi-neutrality condition for neoclassical transport in stellarators

    International Nuclear Information System (INIS)

    Beidler, C.D.; Maassberg, H.

    2005-01-01

    In conventional stellarator neoclassical theory, the transport coefficients are determined so as to satisfy the so-called ambipolarity constraint on the radial particle fluxes but without regard to the additional requirement that the underlying solutions of the kinetic equation also fulfill local quasi-neutrality. This neglect is consistent with the assumption that density, n and electrostatic potential, Φ, are constant on a flux surface and is justified in the literature with analytic scaling arguments which demonstrate that quasi-neutrality introduces variations of n and Φ on a flux surface which have only a modest impact on bulk-plasma transport. The consequences for impurity transport have not been considered. In this contribution, the implications which the quasi-neutrality condition has for neoclassical transport in stellarators are investigated using a version of the General Solution of the Ripple-Averaged Kinetic Equation (GSRAKE) which accounts for the variation of Φ on flux surfaces. Solutions of the kinetic equation which simultaneously fulfill the ambipolarity and the quasi-neutrality conditions are determined iteratively using standard methods for solving systems of non-linear equations, given specified density and temperature profiles for pure hydrogen plasmas. For a conventional heliotron device, it is shown that quasi-neutrality significantly reduces the radial extent of the region in which multiple solutions of the ambipolarity condition can exist. Especially in the plasma periphery, where strong density and temperature gradients are found, the magnitude of the 'ion' root is reduced significantly leading to increased particle and energy fluxes. For strongly drift-optimized stellarators, on the other hand, bulk plasma transport is much less affected. In a small number of cases, the non-linear system of equations produces additional solutions which are not possible when only ambipolarity is enforced, but such cases are rare. Finally, it is

  13. Application of diffusion theory to the transport of neutral particles in fusion plasmas

    International Nuclear Information System (INIS)

    Hasan, M.Z.

    1985-01-01

    It is shown that the widely held view that diffusion theory can not provide good accuracy for the transport of neutral particles in fusion plasmas is misplaced. In fact, it is shown that multigroup diffusion theory gives quite good accuracy as compared to the transport theory. The reasons for this are elaborated and some of the physical and theoretical reasons which make the multigroup diffusion theory provide good accuracy are explained. Energy dependence must be taken into consideration to obtain a realistic neutral atom distribution in fusion plasmas. There are two reasons for this; presence of either is enough to necessitate an energy dependent treatment. First, the plasma temperature varies spatially, and second, the ratio of charge-exchange to total plasma-neutral interaction cross section (c) is not close to one. A computer code to solve the one-dimensional multigroup diffusion theory in general geometry (slab, cylindrical and spherical) has been written for use on Cray computers, and its results are compared with those from the one-dimensional transport code ANISN to support the above finding. A fast, compact and versatile two-dimensional finite element multigroup diffusion theory code, FINAT, in X-Y and R-Z cylindrical/toroidal geometries has been written for use on CRAY computers. This code has been compared with the two dimensional transport code DOT-4.3. The accuracy is very good, and FENAT runs much faster compared even to DOT-4.3 which is a finite difference code

  14. Electron-hole collision limited transport in charge-neutral bilayer graphene

    Science.gov (United States)

    Nam, Youngwoo; Ki, Dong-Keun; Soler-Delgado, David; Morpurgo, Alberto F.

    2017-12-01

    Ballistic transport occurs whenever electrons propagate without collisions deflecting their trajectory. It is normally observed in conductors with a negligible concentration of impurities, at low temperature, to avoid electron-phonon scattering. Here, we use suspended bilayer graphene devices to reveal a new regime, in which ballistic transport is not limited by scattering with phonons or impurities, but by electron-hole collisions. The phenomenon manifests itself in a negative four-terminal resistance that becomes visible when the density of holes (electrons) is suppressed by gate-shifting the Fermi level in the conduction (valence) band, above the thermal energy. For smaller densities, transport is diffusive, and the measured conductivity is reproduced quantitatively, with no fitting parameters, by including electron-hole scattering as the only process causing velocity relaxation. Experiments on a trilayer device show that the phenomenon is robust and that transport at charge neutrality is governed by the same physics. Our results provide a textbook illustration of a transport regime that had not been observed previously and clarify the nature of conduction through charge-neutral graphene under conditions in which carrier density inhomogeneity is immaterial. They also demonstrate that transport can be limited by a fully electronic mechanism, originating from the same microscopic processes that govern the physics of Dirac-like plasmas.

  15. Asymptotic theory of neutral stability of the Couette flow of a vibrationally excited gas

    Science.gov (United States)

    Grigor'ev, Yu. N.; Ershov, I. V.

    2017-01-01

    An asymptotic theory of the neutral stability curve for a supersonic plane Couette flow of a vibrationally excited gas is developed. The initial mathematical model consists of equations of two-temperature viscous gas dynamics, which are used to derive a spectral problem for a linear system of eighth-order ordinary differential equations within the framework of the classical linear stability theory. Unified transformations of the system for all shear flows are performed in accordance with the classical Lin scheme. The problem is reduced to an algebraic secular equation with separation into the "inviscid" and "viscous" parts, which is solved numerically. It is shown that the thus-calculated neutral stability curves agree well with the previously obtained results of the direct numerical solution of the original spectral problem. In particular, the critical Reynolds number increases with excitation enhancement, and the neutral stability curve is shifted toward the domain of higher wave numbers. This is also confirmed by means of solving an asymptotic equation for the critical Reynolds number at the Mach number M ≤ 4.

  16. Business case extension of the H-gas transport system

    International Nuclear Information System (INIS)

    2006-09-01

    This document presents an investment proposal for expansion of the Dutch high calorific gas transport grid. This capacity expansion is needed due to changes in gas flows within and through the Netherlands resulting from changes in the Northwestern European gas market, the loss of local production, the increase of inland demand and the increase of international transit transport. The proposed investment enables expansion of entry capacity in the northeast of the Netherlands, expansion of exit capacity in (especially) the south of the Netherlands and expansion of transport capacity in the intervening area of the national gas transport network. [mk] [nl

  17. Electron collection enhancement arising from neutral gas jets on a charged vehicle in the ionosphere

    International Nuclear Information System (INIS)

    Gilchrist, B.E.; Banks, P.M.; Neubert, T.; Williamson, P.R.; Myers, N.B.; Raitt, W.J.; Sasaki, Susumu

    1990-01-01

    Observations of current collection enhancements due to cold nitrogen gas control jet emissions from a highly charged, isolated rocket payload in the ionosphere have been made during the cooperative high altitude rocket gun experiment (CHARGE) 2 using an electrically tethered mother/daughter payload system. The current collection enhancement was observed on a platform (daughter payload) located 100 to 400 m away from the main payload firing an energetic electron beam (mother payload). The authors interpret these results in terms of an electrical discharge forming in close proximity to the daughter vehicle during the short periods of gas emission. The results indicate that it is possible to enhance the electron current collection capability of positively charged vehicles by means of deliberate neutral gas releases into an otherwise undisturbed space plasma. The results are also compared with recent laboratory observations of hollow cathode plasma contactors operating in the ignited mode

  18. RAETRAD MODEL OF RADON GAS GENERATION, TRANSPORT, AND INDOOR ENTRY

    Science.gov (United States)

    The report describes the theoretical basis, implementation, and validation of the Radon Emanation and Transport into Dwellings (RAETRAD) model, a conceptual and mathematical approach for simulating radon (222Rn) gas generation and transport from soils and building foundations to ...

  19. The three-dimensional, discrete ordinates neutral particle transport code TORT: An overview

    International Nuclear Information System (INIS)

    Azmy, Y.Y.

    1996-01-01

    The centerpiece of the Discrete Ordinates Oak Ridge System (DOORS), the three-dimensional neutral particle transport code TORT is reviewed. Its most prominent features pertaining to large applications, such as adjustable problem parameters, memory management, and coarse mesh methods, are described. Advanced, state-of-the-art capabilities including acceleration and multiprocessing are summarized here. Future enhancement of existing graphics and visualization tools is briefly presented

  20. Performing three-dimensional neutral particle transport calculations on tera scale computers

    International Nuclear Information System (INIS)

    Woodward, C.S.; Brown, P.N.; Chang, B.; Dorr, M.R.; Hanebutte, U.R.

    1999-01-01

    A scalable, parallel code system to perform neutral particle transport calculations in three dimensions is presented. To utilize the hyper-cluster architecture of emerging tera scale computers, the parallel code successfully combines the MPI message passing and paradigms. The code's capabilities are demonstrated by a shielding calculation containing over 14 billion unknowns. This calculation was accomplished on the IBM SP ''ASCI-Blue-Pacific computer located at Lawrence Livermore National Laboratory (LLNL)

  1. Equivalent effect of neutral gas pressure and transverse magnetic field in low-pressure glow discharge plasma

    International Nuclear Information System (INIS)

    Toma, M.; Rusu, Ioana; Pohoata, V.; Mihaila, I.

    2001-01-01

    In the paper it is emphasized the equivalent effect of the neutral gas pressure and the action of a transverse magnetic field (TMF), respectively, on a striated positive plasma column. Experimental and theoretical results prove that the distance between striations has the same variation under the influence of both neutral gas pressure and the action of TMF. The pressure modification as well as the action of a TMF can induce ionization instability in the plasma column which explains the standing striation appearance. (authors)

  2. Some estimates of mirror plasma startup by neutral beam heating of pellet and gas cloud targets

    International Nuclear Information System (INIS)

    Shearer, J.W.; Willmann, P.A.

    1978-01-01

    Hot plasma buildup by neutral beam injection into an initially cold solid or gaseous target is found to be conceivable in large mirror machine experiments such as 2XIIB or MFTF. A simple analysis shows that existing neutral beam intensities are sufficient to ablate suitable targets to form a gas or vapor cloud. An approximate rate equation model is used to follow the subsequent processes of ionization, heating, and hot plasma formation. Solutions of these rate equations are obtained by means of the ''GEAR'' techniques for solving ''stiff'' systems of differential equations. These solutions are in rough agreement with the 2XIIB stream plasma buildup experiment. They also predict that buildup on a suitable nitrogen-like target will occur in the MFTF geometry. In 2XIIB the solutions are marginal; buildup may be possible, but is not certain

  3. Natural Gas Container Transportation: the Alternative Way to Solve the World’s Energy Transportation Problems

    Directory of Open Access Journals (Sweden)

    A.M. Shendrik

    2014-03-01

    Full Text Available The container gas transportation for low and medium level consumers as an alternative to pipelines is considered. The options for gas supply schemes, based on road and rail transport are given. The advantages and disadvantages of both types of gas transporting are described, the areas of their effective using are separated in the article. Promising implementations of technology in environment of economic crisis and also considering world trends of energy development are presented. The most advanced organization of compressed gas condensate transportation of unprepared gas fields in large diameter universal cylindrical balloons (up to 1000 mm are reasoned. The problem of compressed gas sea transportation are well disclosed, but the alternative ways of gas transportation by land are not investigated enough. Compressed Natural Gas (CNG Technology - is new promising technology for natural gas transportation by specially designed vessels – CNG-vessels. The feature of this technology is that natural gas can be downloaded directly near gas deposits and unloaded - directly into the customer's network. This eliminates significant capital investments in underwater pipelining or gas liquefaction plants. The main objects of investment are CNG-vessels themselves. The most attractive places for implementation of CNG-technology are sea (offshore natural gas deposits. Numerous international experts estimate the natural gas transportation by CNG-vessels in 1.5-2.0 times more cost-beneficial in comparison with offshore pipelines transportation, or in comparison with LNG (Liquefied Natural Gas shipping with natural gas transportation volume between 0.5 and 4.0 billion cubic meters per year on the route from 250 to 2,500 sea miles. This technology makes possible to provide gas supplement to the mountain and abounding in water areas, remote and weakly gasified regions. Described technology deserves special attention in the case of depleted and low-power oil and

  4. Existence of a critical point in the phase diagram of the ideal relativistic neutral Bose gas

    International Nuclear Information System (INIS)

    Park, Jeong-Hyuck; Kim, Sang-Woo

    2011-01-01

    We explore the phase transitions of the ideal relativistic neutral Bose gas confined in a cubic box, without assuming the thermodynamic limit nor continuous approximation. While the corresponding non-relativistic canonical partition function is essentially a one-variable function depending on a particular combination of temperature and volume, the relativistic canonical partition function is genuinely a two-variable function of them. Based on an exact expression for the canonical partition function, we performed numerical computations for up to 10 5 particles. We report that if the number of particles is equal to or greater than a critical value, which amounts to 7616, the ideal relativistic neutral Bose gas features a spinodal curve with a critical point. This enables us to depict the phase diagram of the ideal Bose gas. The consequent phase transition is first order below the critical pressure or second order at the critical pressure. The exponents corresponding to the singularities are 1/2 and 2/3, respectively. We also verify the recently observed 'Widom line' in the supercritical region.

  5. Detection of cold gas releases in space via low energy neutral atom imaging

    International Nuclear Information System (INIS)

    McComas, D.J.; Funsten, H.O.; Moore, K.R.; Scime, E.E.; Thomsen, M.F.

    1993-01-01

    Low energy neutral atoms (LENAs) are produced in space plasmas by charge exchange between the ambient magnetospheric plasma ions and cold neutral atoms. Under normal conditions these cold neutrals come from the terrestrial geocorona, a shroud of few-eV hydrogen atoms surrounding the Earth. As a consequence of this charge exchange, it has become possible to remotely image many regions of the magnetosphere for the first time utilizing recently developed LENA imaging technology. In addition to the natural hydrogen geocorona, conventional explosions and maneuvering thruster firings can also introduce large amounts of cold gas into the space environment. In this paper the authors examine whether such potentially clandestine activities could also be remotely observed for the first time via LENA imaging. First, they examine the fluxes of LENAs produced in the space environment from a conventional explosion. Then they review the present state of the art in the emerging field of LENA detection and imaging. Recent work has shown that LENAs can be imaged by first converting the neutrals to ions with ultra-thin (10s of angstrom) foils and then electrostatically analyzing these newly created ions to reject the large (> 10 10 cm -2 s -1 ) UV background to which the low energy detectors are sensitive. They conclude that the sensitivities for present LENA imager designs may be just adequate for detecting some man-made releases. With additional improvements in LENA detection capabilities, this technique could become an important new method for monitoring for conventional explosions, as well as other man-made neutral releases, in the space environment

  6. Electron and ion heat transport with lower hybrid current drive and neutral beam injection heating in ASDEX

    International Nuclear Information System (INIS)

    Soeldner, F.X.; Pereverzev, G.V.; Bartiromo, R.; Fahrbach, H.U.; Leuterer, F.; Murmann, H.D.; Staebler, A.; Steuer, K.H.

    1993-01-01

    Transport code calculations were made for experiments with the combined operation of lower hybrid current drive and heating and of neutral beam injection heating on ASDEX. Peaking or flattening of the electron temperature profile are mainly explained by modifications of the MHD induced electron heat transport. They originate from current profile changes due to lower hybrid and neutral beam current drive and to contributions from the bootstrap current. Ion heat transport cannot be described by one single model for all heating scenarios. The ion heat conductivity is reduced during lower hybrid heated phases with respect to Ohmic and neutral beam heating. (author). 13 refs, 5 figs

  7. A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

    International Nuclear Information System (INIS)

    Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K.; Hu, Han-Shi; Li, Jun

    2013-01-01

    Sheltering thorium ions: A Th 4+ ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L) 3 4+ is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Hu, Han-Shi [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); Li, Jun [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (United States)

    2013-07-01

    Sheltering thorium ions: A Th{sup 4+} ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L){sub 3}{sup 4+} is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. First in situ plasma and neutral gas measurements at comet Halley: initial VEGA results

    International Nuclear Information System (INIS)

    Gringauz, K.I.; Remizov, A.P.; Gombosi, T.I.

    1986-04-01

    The first in situ observations and a description of the large scale behaviour of comet Halley's plasma environment are presented. The scientific objectives of the PLASMAG-1 experiment were as follows: to study the change of plasma parameters and distributions as a function of cometocentric distance; to investigate the existence and structure of the cometary bow shock; to determine the change in chemical composition of the heavily mass loaded plasma as the spacecraft approached the comet; and to measure the neutral gas distribution along the spacecraft trajectory. (author)

  10. Alaskan North Slope Oil & Gas Transportation Support

    Energy Technology Data Exchange (ETDEWEB)

    Lilly, Michael Russell [Geo-Watersheds Scientific LLC, Fairbanks, AK (United States)

    2017-03-31

    early or risk being caught on ice roads with flooded stream crossings, or unusable sections of ice road due to local melt. These challenges result in higher oil and gas field exploration and operational costs. Much of the scientific understanding to address transportation issues for oil and gas development on the North Slope exists, but has not been placed into a set of tools and data sets useful for industry and management agencies. Optimizing North Slope transportation networks during winter operation seasons is critical in managing increasing resource development and will provide a framework for environmentally-responsive development. Understanding the physical environment (such as snow, water, ice, soils) is necessary to ensure protection of fisheries and other natural resources on the sensitive tundra landscape. Solutions also have to do more than just describe current conditions, they need the ability to forecast short-term conditions. This will allow management agencies to respond to future variability in snow cover, soil temperature, and water availability more effectively. In turn, industry will then have more time to plan the significant mobilization taking place every winter season.

  11. Development of natural gas ocean transportation chain by means of natural gas hydrate (NGH)

    International Nuclear Information System (INIS)

    Nogami, T.; Oya, N.; Ishida, H.; Matsumoto, H.

    2008-01-01

    Recent studies in Japan have suggested that natural gas hydrate (NGH) transportation of natural gas is more economical than liquefied natural gas (LNG) transportation systems for small, medium and remote gas fields. Researchers in Japan have built a 600 kg per day NGH production and pelletizing plant and regasification facility. This paper discussed feasibility studies conducted in southeast Asia to determine the unit's commercialization potential with large natural gas-related businesses including shipping companies and electric power utilities. The total supply chain was compared with the corresponding liquefied natural gas (LNG) and compressed natural gas (CNG) supply chains. The study also examined natural gas reserves, energy policies, the positioning of natural gas supplies, and future forecasts of natural gas demand. A conceptual design for an NGH supply chain in Indonesia was presented. Results of the study have demonstrated that the NGH chain is an appropriate and economically feasible transportation method for many areas in southeast Asia. 8 refs., 10 figs

  12. TFTR neutral beam D-T gas injection system operational experiences of the first two years

    International Nuclear Information System (INIS)

    Oldaker, M.E.; Lawson, J.E.; Stevenson, T.N.; Kamperschroer, J.H.

    1995-01-01

    The TFTR Neutral Beam Tritium Gas Injection System (TGIS) has successfully performed tritium operations since December 1993. TGIS operation has been reliable, with no leaks to the secondary containment to date. Notable operational problems include throughput leaks on fill, exit and piezoelectric valves. Repair of a TGIS requires replacement of the assembly, involving TFTR downtime and extensive purging, since the TGIS assembly is highly contaminated with residual tritium, and is located within secondary containment. Modifications to improve reliability and operating range include adjustable reverse bias voltage to the piezoelectric valves, timing and error calculation changes to tune the PLC and hardwired timing control, and exercising piezoelectric valves without actually pulsing gas prior to use after extended inactivity. A pressure sensor failure required the development of an open loop piezoelectric valve drive control scheme, using a simple voltage ramp to partially compensate for declining plenum pressure. Replacement of TGIS's have been performed, maintaining twelve system tritium capability as part of scheduled project maintenance activity

  13. Gasoline and other transportation fuels from natural gas in Canada

    International Nuclear Information System (INIS)

    Symons, E.A.; Miller, A.I.

    1981-03-01

    Ways in which natural gas might displace cude oil as a source of fuels for the Canadian transportation market are reviewed. Three approaches are possible: (1) direct use as compressed natural gas; (2)conversion of natural gas to methanol; and (3) further conversion of methanol to synthetic gasoline. (author)

  14. Transport of a nonneutral electron plasma due to electron collisions with neutral atoms

    International Nuclear Information System (INIS)

    Douglas, M.H.; O'Neil, T.M.

    1978-01-01

    Transport of a nonneutral electron plasma across a magnetic field is caused by electron scattering from ambient neutral atoms. A theoretical model of such transport is presented, assuming the plasma is quiescent and the scattering is elastic scattering from infinite mass scattering centers of constant momentum transfer cross section. This model is motivated by recent experiments. A reduced transport equation is obtained by expanding the Boltzmann equation for the electron distribution in inverse powers of the magnetic field. The equation together with Poisson's equation for the radial electric field, which must exist in a nonneutral column, determine the evolution of the system. When these two equations are properly scaled, they contain only a single parameter: the ratio of initial Debye length to initial column radius. For cases where this parameter is either large or small, analytical solutions, or at least partial solutions, are obtained. For intermediate values of the parameter, numerical solutions are obtained

  15. Identification of a disulfide bridge important for transport function of SNAT4 neutral amino acid transporter.

    Directory of Open Access Journals (Sweden)

    Rugmani Padmanabhan Iyer

    Full Text Available SNAT4 is a member of system N/A amino acid transport family that primarily expresses in liver and muscles and mediates the transport of L-alanine. However, little is known about the structure and function of the SNAT family of transporters. In this study, we showed a dose-dependent inhibition in transporter activity of SNAT4 with the treatment of reducing agents, dithiothreitol (DTT and Tris(2-carboxyethylphosphine (TCEP, indicating the possible involvement of disulfide bridge(s. Mutation of residue Cys-232, and the two highly conserved residues Cys-249 and Cys-321, compromised the transport function of SNAT4. However, this reduction was not caused by the decrease of SNAT4 on the cell surface since the cysteine-null mutant generated by replacing all five cysteines with alanine was equally capable of being expressed on the cell surface as wild-type SNAT4. Interestingly, by retaining two cysteine residues, 249 and 321, a significant level of L-alanine uptake was restored, indicating the possible formation of disulfide bond between these two conserved residues. Biotinylation crosslinking of free thiol groups with MTSEA-biotin provided direct evidence for the existence of a disulfide bridge between Cys-249 and Cys-321. Moreover, in the presence of DTT or TCEP, transport activity of the mutant retaining Cys-249 and Cys-321 was reduced in a dose-dependent manner and this reduction is gradually recovered with increased concentration of H2O2. Disruption of the disulfide bridge also decreased the transport of L-arginine, but to a lesser degree than that of L-alanine. Together, these results suggest that cysteine residues 249 and 321 form a disulfide bridge, which plays an important role in substrate transport but has no effect on trafficking of SNAT4 to the cell surface.

  16. Compressed natural gas transportation by utilizing FRP composite pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, S.C. [Trans Ocean Gas Inc., St. John' s, NF (Canada)

    2004-07-01

    This paper discussed the Trans Ocean Gas (TOG) method for transporting compressed natural gas (CNG). As demand for natural gas increases and with half of the world's reserves considered stranded, a method to transport natural gas by ship is needed. CNG transportation is widely viewed as a viable method. Transported as CNG, stranded gas reserves can be delivered to existing markets or can create new natural gas markets not applicable to liquefied natural gas (LNG). In contrast to LNG, compressed gas requires no processing to offload. TOG proposes that CNG be transported using fiber reinforced plastic (FRP) pressure vessels which overcome all the deficiencies of proposed steel-based systems. FRP pressure vessels have been proven safe and reliable through critical applications in the national defense, aerospace, and natural gas vehicle industries. They are light-weight, highly reliable, have very safe failure modes, are corrosion resistant, and have excellent low temperature characteristics. Under TOG's scheme, natural gas can be stored at two thirds the density of LNG without costly processing. TOG's proposed design and testing of a CNG system was reviewed in detail. 1 fig.

  17. Gas Transport and Exchange through Wetland Plant Aerenchyma

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith; Brix, Hans

    2013-01-01

    Aerenchyma, the large airspaces in aquatic plants, is a rapid gas transport pathway between atmosphere and soil in wetlands. Oxygen transport aerates belowground tissue and oxidizes rhizosphere soil, an important process in wetland biogeochemistry. Most plant O2 transport occurs by diffusion...

  18. The Contribution of Natural Gas Vehicles to Sustainable Transport

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The transport sector is currently responsible for 23% of energy-related CO2 emissions, and transport associated CO2 emissions will more than double by 2050. This working paper evaluates the potential costs and benefits of using natural gas as a vehicle fuel for road transportation, as well as the policy related to its market development.

  19. Optimizing beam transport in rapidly compressing beams on the neutralized drift compression experiment – II

    Directory of Open Access Journals (Sweden)

    Anton D. Stepanov

    2018-03-01

    Full Text Available The Neutralized Drift Compression Experiment-II (NDCX-II is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-m-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on the scintillator gives the radius of the beam, but the envelope angle is not measured directly. We demonstrate how the parameters of the beam envelope (radius, envelop angle, and emittance can be reconstructed from a series of images taken by varying the B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section. Keywords: Charged-particle beams, Induction accelerators, Beam dynamics, Beam emittance, Ion beam diagnostics, PACS Codes: 41.75.-i, 41.85.Ja, 52.59.Sa, 52.59.Wd, 29.27.Eg

  20. Evaluation of axial fission gas transport in power ramping experiments

    International Nuclear Information System (INIS)

    Kinoshita, Motoyasu

    1986-01-01

    The LINUS code calculates advective and diffusional transport of fission gas towards an upper plenum through the pellet-cladding gap. The basic equations were modified for analyzing a multi-component gas mixture in the gap and also for dealing with opening and/or closing of the gap, which induces additional axial gas flow. Analysis of the Petten ramp experiment shows that helium pressurization is effective in suppressing an ascending rate of fission gas concentration. After the maximum concentration is achieved through power ramping, the gas concentration could be described by a steady state analytical solution which does not depend on the filling gas pressure. (author)

  1. Natural gas transport with the aid of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Volk, A

    1978-01-01

    After giving a brief explanation on the term natural gas and the chemical composition of natural gases of different origin, the natural gas supply in the FRG and in Western Europe is discussed. Other discussions are included on: (1) planning, construction, and operation of the pipelines; (2) the equipment for pressure increase and the telecommunication equipment which are urgently necessary for gas transport through pipelines; (3) the problem of safety both in connection with the supply and protection of man and material; and (4) problems of profitability of natural gas transport through pipelines.

  2. Transport Properties of operational gas mixtures used at LHC

    CERN Document Server

    Assran, Yasser

    2011-01-01

    This report summarizes some useful data on the transport characteristics of gas mixtures which are required for detection of charged particles in gas detectors. We try to replace Freon used for RPC detector in the CMS experiment with another gas while maintaining the good properties of the Freon gas mixture unchanged. We try to switch to freonless gas mixture because Freon is not a green gas, it is very expensive and its availability is decreasing. Noble gases like Ar, He, Ne and Xe (with some quenchers like carbon dioxide, methane, ethane and isobutene) are investigated. Transport parameters like drift velocity, diffusion, Townsend coefficient, attachment coefficient and Lorentz angle are computed using Garfield software for different gas mixtures and compared with experimental data.

  3. THREEDANT: A code to perform three-dimensional, neutral particle transport calculations

    International Nuclear Information System (INIS)

    Alcouffe, R.E.

    1994-01-01

    The THREEDANT code solves the three-dimensional neutral particle transport equation in its first order, multigroup, discrate ordinate form. The code allows an unlimited number of groups (depending upon the cross section set), angular quadrature up to S-100, and unlimited Pn order again depending upon the cross section set. The code has three options for spatial differencing, diamond with set-to-zero fixup, adaptive weighted diamond, and linear modal. The geometry options are XYZ and RZΘ with a special XYZ option based upon a volume fraction method. This allows objects or bodies of any shape to be modelled as input which gives the code as much geometric description flexibility as the Monte Carlo code MCNP. The transport equation is solved by source iteration accelerated by the DSA method. Both inner and outer iterations are so accelerated. Some results are presented which demonstrate the effectiveness of these techniques. The code is available on several types of computing platforms

  4. The suite of analytical benchmarks for neutral particle transport in infinite isotropically scattering media

    International Nuclear Information System (INIS)

    Kornreich, D.E.; Ganapol, B.D.

    1997-01-01

    The linear Boltzmann equation for the transport of neutral particles is investigated with the objective of generating benchmark-quality evaluations of solutions for homogeneous infinite media. In all cases, the problems are stationary, of one energy group, and the scattering is isotropic. The solutions are generally obtained through the use of Fourier transform methods with the numerical inversions constructed from standard numerical techniques such as Gauss-Legendre quadrature, summation of infinite series, and convergence acceleration. Consideration of the suite of benchmarks in infinite homogeneous media begins with the standard one-dimensional problems: an isotropic point source, an isotropic planar source, and an isotropic infinite line source. The physical and mathematical relationships between these source configurations are investigated. The progression of complexity then leads to multidimensional problems with source configurations that also emit particles isotropically: the finite line source, the disk source, and the rectangular source. The scalar flux from the finite isotropic line and disk sources will have a two-dimensional spatial variation, whereas a finite rectangular source will have a three-dimensional variation in the scalar flux. Next, sources emitting particles anisotropically are considered. The most basic such source is the point beam giving rise to the Green's function, which is physically the most fundamental transport problem, yet may be constructed from the isotropic point source solution. Finally, the anisotropic plane and anisotropically emitting infinite line sources are considered. Thus, a firm theoretical and numerical base is established for the most fundamental neutral particle benchmarks in infinite homogeneous media

  5. Light-emitting Si films formed by neutral cluster deposition in a thin O2 gas

    International Nuclear Information System (INIS)

    Honda, Y.; Takei, M.; Ohno, H.; Shida, S.; Goda, K.

    2005-01-01

    We have fabricated the light-emitting Si-rich and oxygen-rich amorphous SiO 2 (a-SiO 2 ) films using the neutral cluster deposition (NCD) method without and with oxygen gas admitted, respectively, and demonstrate for the first time that these films show a photoluminescent feature. The Si thin films were observed by atomic force microscopy and high-resolution transmission electron microscopy, and analyzed by means of X-ray photoelectron spectroscopy, photoluminescence (PL) and FTIR-attenuated total reflection measurements. All of the PL spectra show mountainous distribution with a peak around 620 nm. It is found that the increase in the oxygen termination in the a-SiO 2 films evidently makes the PL intensity increase. It is demonstrated that NCD technique is one of the hopeful methods to fabricate light-emitting Si thin films

  6. Performance test results of ion beam transport for SST-1 neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Jana, M R; Mattoo, S K [Institute for Plasma Research Bhat, Gandhinagar-382428, Gujarat (India); Uhlemann, R, E-mail: mukti@ipr.res.i [Forschungszentrum Juelich, Institute fur Energieforschung IEF-4, Plasmaphysik D-52425 Juelich (Germany)

    2010-02-01

    A neutral beam injector is built at IPR to heat the plasma of SST-1 and its upgrade. It delivers a maximum beam power of 1.7 MW for 55 kV Hydrogen beam or 80 kV Deuterium beam. At lower beam voltage, the delivered power falls to 500 kW at 30 kV Hydrogen beam which is adequate to heat SST-1 plasma ions to {approx} 1 keV. Process of acceleration of ions to the required beam voltage, conversion of ions to neutrals and removal of un-neutralized ions and the beam diagnostic systems occupy a large space. The consequence is that linear extent of the neutral beam injector is at least a few meters. Also, port access provides a very narrow duct. Even a very good injector design and fabrication practices keep beam divergence at a very low but finite value. The result is beam transport becomes an important issue. Since a wide area beam is constructed by hundreds of beam lets, it becomes essential they be focused in such a way that beam transport loss is minimized. Horizontal and vertical focal lengths are two parameters, in addition to beam divergence, which give a description of the beam transport. We have obtained these two parameters for our injector by using beam transport code; making several hundred simulation runs by varying optical parameters of the beam. The selected parameters set has been translated into the engineering features of the extractor grid set of the ion source. Aperture displacement technique is used to secure the horizontal beam focusing at 5.4 m. Combination of both aperture displacement and inclining of two grid halves to {approx} 17 mrad are secured for vertical beam focusing at 7 m from earth grid of the ion source. The gaps between the design, engineered and performance tested values usually arise due to lack of exercising control over fabrication processes or due to inaccuracies in the assumption made in the model calculations of beam optics and beam transport. This has been the case with several injectors, notably with JET injector. To overcome

  7. Incorporating greenhouse gas (GHG) emissions in long range transportation planning.

    Science.gov (United States)

    2014-05-01

    Greenhouse gas (GHG) emissions continue to be an important focus area for state, local, and federal : agencies. The transportation sector is the second biggest contributor to GHG emissions in the U.S., and : Texas contributes the highest emissions am...

  8. Wind turbines application for energy savings in Gas transportation system

    OpenAIRE

    Mingaleeva, Renata

    2014-01-01

    The Thesis shows the perspectives of involving renewable energy resources into the energy balance of Russia, namely the use of wind energy for the purpose of energy supply for the objects of the Russian Gas transportation system. The methodology of the wind energy technical potential calculation is designed and the wind energy technical potential assessment for onshore and offshore zones of Russia is presented. The analysis of Russian Gas transportation system in terms of energy consumption i...

  9. Analytical solution for the transport equation for neutral particles in cylindrical and Cartesian geometry

    International Nuclear Information System (INIS)

    Goncalves, Glenio Aguiar

    2003-01-01

    In this work, we are reported analytical solutions for the transport equation for neutral particles in cylindrical and cartesian geometry. For the cylindrical geometry, it is applied the Hankel transform of order zero in the S N approximation of the one-dimensional cylindrical transport equation, assuming azimuthal symmetry and isotropic scattering. This procedure is coined HTSN method. The anisotropic problem is handled using the decomposition method, generating a recursive approach, which the HTSN solution is used as initial condition. For cartesian geometry, the one and two dimensional transport equation is derived in the angular variable as many time as the degree of the anisotropic scattering. This procedure leads to set of integro-differential plus one differential equation that can be really solved by the variable separation method. Following this procedure, it was possible to come out with the Case solution for the one-dimensional problem. Numerical simulations are reported for the cylindrical transport problem both isotropic and anisotropic case of quadratic degree. (author)

  10. Gas Transport and Exchange through Wetland Plant Aerenchyma

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith; Brix, Hans

    2013-01-01

    Aerenchyma, the large airspaces in aquatic plants, is a rapid gas transport pathway between atmosphere and soil in wetlands. Oxygen transport aerates belowground tissue and oxidizes rhizosphere soil, an important process in wetland biogeochemistry. Most plant O2 transport occurs by diffusion......, and the major challenge for its accurate measurement is avoiding disturbing small-scale gradients in O2 concentration and demand in the pathway. Small O2 sensors with rapid response times and high spatial resolution are the most popular methods for quantifying O2 transport and rhizosphere oxidation...... such as stirring of solutions. In some species, pressurized gas flows develop in shoots and rhizomes, and their contribution to gas fluxes can be assessed with pressure transducers and flow meters. Other gases produced in wetlands (e.g., CO2, CH4, and N2O) are also transported in aerenchyma. Their fluxes...

  11. On the neutralization of noble gas ions in low energy ion scattering

    International Nuclear Information System (INIS)

    Draxler, M.

    2003-04-01

    The set-up ACOLISSA has been set to operation. It was thoroughly tested and found to completely fulfill the requirements for the measurement of charge integrated and of ion TOF-LEIS spectra. Charge integrated scattering spectra in LEIS exhibit a surface peak in many experimental conditions. It was shown that the appearance of this peak is due to a reduced energy width of the contribution from the surface layer and partly due to a reduced energy loss in the surface layer as compared to deeper layers. In the regime of strong multiple scattering, both reasons reflect the fact, that scattering from surface atoms occurs practically exclusively by single binary collisions, while plural and multiple scattering set in in the subsurface layers. As a consequence, only the surface layer and to some extent also the second layer will contribute to the surface peak. Experiment as well as simulation show this behavior, so that other possible reasons for the appearance of a surface peak (e.g. channeling) can safely be ruled out. At high energies, when the multiple scattering half width angle is small, surface effects are mainly caused by electronic stopping and become small, as observed in both, experiment and simulation. In this regime, the energy spectrum is well described by the single scattering spectrum. From the present thesis one can draw the following conclusions concerning the neutralization of noble gas ions at metal surfaces: below the threshold for collision induced processes (CIN, CIR) Ε Εth), P+ is governed by local processes (collision induced neutralization and collision induced reionization) and by a non-local process (Auger neutralization), and thus depends on the energy as well as on vperp. From experiments like the one presented here, where the ion energy as well as the scattering geometry are varied, the process parameters of the neutralization can uniquely be determined for any system. These findings are generally valid and reveal the relevance of different

  12. Impurity transport during neutral beam injection in the ISX-B tokamak

    International Nuclear Information System (INIS)

    Isler, R.C.; Crume, E.C.; Arnurius, D.E.; Murray, L.E.

    1980-10-01

    In ohmically heated ISX-B discharges, both the intrinsic iron impurity ions and small amounts of argon introduced as a test gas accumulate at the center of the plasma. But during certain beam-heated discharges, it appears that this accumulation does not take place. These results may reflect the conclusion of Stacey and Sigmar that momentum transferred from the beams to the plasma can inhibit inward impurity transport

  13. Underground Coal Gasification: Rates of Post Processing Gas Transport

    Czech Academy of Sciences Publication Activity Database

    Soukup, Karel; Hejtmánek, Vladimír; Stanczyk, K.; Šolcová, Olga

    2014-01-01

    Roč. 68, č. 12 (2014), s. 1707-1715 ISSN 0366-6352 R&D Projects: GA MŠk 7C12017 Grant - others:RFCS(XE) RFCR-CT-2011-00002 Institutional support: RVO:67985858 Keywords : underground coal gas ification * gas transport * textural properties Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.468, year: 2014

  14. Water vapor and Gas Transport through Polymeric Membranes

    NARCIS (Netherlands)

    Metz, S.J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

  15. Diagnostics of discharge channels for neutralized chamber transport in heavy ion fusion

    International Nuclear Information System (INIS)

    Niemann, C.; Penache, D.; Tauschwitz, A.; Rosmej, F.B.; Neff, S.; Birkner, R.; Constantin, C.; Knobloch, R.; Presura, R.; Yu, S.S.; Sharp, W.M.; Ponce, D.M.; Hoffmann, D.H.H.

    2002-01-01

    The final beam transport in the reactor chamber for heavy ion fusion in preformed plasma channels offers many attractive advantages compared to other transport modes. In the past few years, experiments at the Gesellschaft fuer Schwerionenforschung (GSI) accelerator facility have addressed the creation and investigation of discharge plasmas, designed for the transport of intense ion beams. Stable, self-standing channels of 50 cm length with currents up to 55 kA were initiated in low-pressure ammonia gas by a CO 2 -laser pulse along the channel axis before the discharge is triggered. The channels were characterized by several plasma diagnostics including interferometry and spectroscopy. We also present first experiments on laser-guided intersecting discharges

  16. Coupled two-dimensional edge-plasma and neutral gas modelling of the DIII-D scrape-off-layer

    International Nuclear Information System (INIS)

    Maingi, R.; Gilligan, J.; Hankins, O.; Rensink, M.; Owen, L.; Klepper, C.; Mioduszewski, P.

    1992-01-01

    This paper reports that in order to do consistent scrape-off-layer plasma and neutral transport calculations, the 2-D fluid code, B2 has been externally coupled to the neutral transport code, DEGAS, for Dlll-D. The coupling procedure is similar to recent simulations done for TFTR, Tore Supra, and ClT. An averaged source approach is utilized to allow convergence between the two codes. Initial comparison of plasma quantities between the coupled code set and the B2 code alone shows that a colder, denser plasma may exist at the divertor targets than predicted by the B2 code with its internal recycling model

  17. Metal enrichment of the neutral gas of blue compact dwarf galaxies: the compelling case of Pox 36

    Science.gov (United States)

    Lebouteiller, V.; Kunth, D.; Thuan, T. X.; Désert, J. M.

    2009-02-01

    Context: Evidence has grown over the past few years that the neutral phase of blue compact dwarf (BCD) galaxies may be metal-deficient as compared to the ionized gas of their H ii regions. These results have strong implications for our understanding of the chemical evolution of galaxies, and it is essential to strengthen the method, as well as to find possible explanations. Aims: We present the analysis of the interstellar spectrum of Pox 36 with the Far Ultraviolet Spectroscopic Explorer (FUSE). Pox 36 was selected because of the relatively low foreground gas content that makes it possible to detect absorption-lines weak enough that unseen components should not be saturated. Methods: Interstellar lines of H i, N i, O i, Si ii, P ii, Ar i, and Fe ii are detected. Column densities are derived directly from the observed line profiles except for H i, whose lines are contaminated by stellar absorption, thus needing the stellar continuum to be removed. We used the TLUSTY models to remove the stellar continuum and isolate the interstellar component. The best fit indicates that the dominant stellar population is B0. The observed far-UV flux agrees with an equivalent number of ~300 B0 stars. The fit of the interstellar H i line gives a column density of 1020.3±0.4 cm-2. Chemical abundances were then computed from the column densities using the dominant ionization stage in the neutral gas. Our abundances are compared to those measured from emission-line spectra in the optical, probing the ionized gas of the H ii regions. Results: Our results suggest that the neutral gas of Pox 36 is metal-deficient by a factor ~7 as compared to the ionized gas, and they agree with a metallicity of ≈1/35 Z_⊙. Elemental depletion is not problematic because of the low dust content along the selected lines of sight. In contrast, the ionized gas shows a clear depletion pattern, with iron being strongly depleted. Conclusions: The abundance discontinuity between the neutral and ionized phases

  18. Membrane topology of rat sodium-coupled neutral amino acid transporter 2 (SNAT2).

    Science.gov (United States)

    Ge, Yudan; Gu, Yanting; Wang, Jiahong; Zhang, Zhou

    2018-07-01

    Sodium-coupled neutral amino acid transporter 2 (SNAT2) is a subtype of the amino acid transport system A that is widely expressed in mammalian tissues. It plays critical roles in glutamic acid-glutamine circulation, liver gluconeogenesis and other biological pathway. However, the topology of the SNAT2 amino acid transporter is unknown. Here we identified the topological structure of SNAT2 using bioinformatics analysis, Methoxy-polyethylene glycol maleimide (mPEG-Mal) chemical modification, protease cleavage assays, immunofluorescence and examination of glycosylation. Our results show that SNAT2 contains 11 transmembrane domains (TMDs) with an intracellular N terminus and an extracellular C terminus. Three N-glycosylation sites were verified at the largest extracellular loop. This model is consistent with the previous model of SNAT2 with the exception of a difference in number of glycosylation sites. This is the first time to confirm the SNAT2 membrane topology using experimental methods. Our study on SNAT2 topology provides valuable structural information of one of the solute carrier family 38 (SLC38) members. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Transport and interaction of a relativistic electron beam in low pressure neutral gases

    International Nuclear Information System (INIS)

    Iyyengar, S.K.; Rohatgi, V.K.

    1989-01-01

    A numerical study of the transport of a 0.27-MeV, 6.6-kA, 40-ns relativistic electron beam in argon and hydrogen in the pressure range of 0.01--1.0 Torr taking into account charge and current neutralization effects is presented. Ionization by avalanching and by beam and plasma electrons is included in the calculation of plasma density buildup. Plasma heating resulting from return current heating and two-stream instability is taken into account. The computed results of charge transport, net current, and breakdown time are compared with experimental results obtained in this laboratory. The results are in reasonable agreement with the experiment and show a maximum charge transport of 75% at the optimum pressure of 0.1 and 0.6 Torr in argon and hydrogen, respectively. The calculations indicate beam-generated plasma parameters of 10 19 --10 20 m -3 density and 1--5 eV electron temperature

  20. Transport of gas from disk to halo in starforming galaxies

    Directory of Open Access Journals (Sweden)

    Shevchenko Mikhail G.

    2017-12-01

    Full Text Available Using 3-D gas dynamic simulations, we study the supernova (SNe driven transport of gas from the galactic disk. We assume that SNe are distributed randomly and uniformly in the galactic plane and we consider sufficiently high volume SNe rates that are typical for starforming galaxies: νSN = (0.3 − 3 × 10−11 pc−3 yr−1. We found that under such conditions, a major part of gas locked initially in the galactic disk is transported up to ∼ 1 − 5 stellar scale heights within several millions years. As expected gas transport is more efficient in the case of a thinner stellar disk. An decrease/increase of SN rate in the galactic disk with the same stellar scale height leads to an enlarging/shortening of time scale for gas transport. Independent of SN rate, the major fraction of the swept up gas is in the cold phase (T 106 K is elevated to larger heights than cold gas.

  1. Ion transport studies on the PLT tokamak during neutral beam injection

    International Nuclear Information System (INIS)

    Suckewer, S.; Cavallo, A.; Cohen, S.

    1983-12-01

    Radial transport of ions during co- and counter-neutral beam heating in the PLT tokamak has been studied, using molybdenum and scandium ions as tracer elements. The time evolution of the radial profiles of several ionization stages of both elements, injected by laser blowoff during the neutral beam heating, were measured under three significantly different beam-plasma combinations. No noticeable differences in the radial profiles attributable to the beam direction were observed. However, a given injected amount resulted in considerably larger interior concentrations of the tracer element in the counter-beam heating cases, suggesting larger penetration of the plasma periphery. Computer simulation with the MIST code suggests a net inward drift of the order 10 3 cm/sec superposed to a diffusion coefficient of the order 10 4 cm 2 /sec for both scandium and molybdenum ions. Injection of larger amounts of the tracer element, sufficient to cause measurable central electron temperature changes, resulted in dramatic changes in ion-state distributions, making some appear peaked in the center while others disappeared. This effect could be produced with both co- and counter-beam heating, but with lesser amounts in the latter case. It is interpreted as rearrangement of the ionization balance, rather than any preferential accumulation of the injected element

  2. Impurity ion transport studies on the PLT tokamak during neutral-beam injection

    International Nuclear Information System (INIS)

    Suckewer, S.; Cavallo, A.; Cohen, S.

    1984-01-01

    Radial transport of medium- and high-Z ions during co- and counter-neutral-beam heating in the PLT tokamak is studied, using molybdenum and scandium ions as tracer elements. The time evolution of the radial profiles of several ionization stages of both elements, injected by laser blowoff during the neutral-beam heating, is measured under three significantly different beam-plasma combinations. No noticeable differences in the radial profiles attributable to the beam direction are observed. However, a given injected amount resulted in considerably larger interior concentrations of the tracer element in the counter-beam heating cases, suggesting larger penetration of the plasma periphery. Computer simulation with the MIST code suggests a net inward drift of the order 10 3 cm.s -1 superposed to a diffusion coefficient of the order 10 4 cm 2 .s -1 for both scandium and molybdenum ions. Injection of larger amounts of the tracer element, sufficient to cause measurable central electron temperature changes, resulted in dramatic changes in ion-state distributions, making some appear peaked in the centre while others disappeared. This effect could be produced with both co- and counter-beam heating, but with lesser amounts in the latter case. It is interpreted as rearrangement of the ionization balance, rather than any preferential accumulation of the injected element. (author)

  3. Separation of British Gas' transportation and storage business

    International Nuclear Information System (INIS)

    McGregor, G.

    1992-12-01

    In making his substantive reference of the transportation and storage business of British Gas to the Monopolies and Mergers Commission, the Director General of Gas Supply identified the following principal effects adverse to the public interest: ''The absence of provision for the establishment of an independent undertaking to operate the pipe-line system and other facilities used by British Gas for the conveyance and storage of gas which would not be subject to conflicting interests in securing (a) transparency of the prices charged, the costs incurred and the operating methods in respect of the conveyance and storage of gas; (b) proper allocation to various parts of the Gas Supply Business of costs incurred and returns by that business; and (c) protection of information relating to the conveyance and storage of gas from which British Gas might obtain unfair commercial advantage, and thereby avoid the restriction or distortion of competition between British Gas and other persons whose business consists of or includes the supply of gas''. This paper considers the structural issues associated with achieving effective competition and looks at how the relationship between the businesses of supply and transportation might be organised in the short and longer term. (Author)

  4. Transport of natural gas; criterions for the infrastructure planning

    International Nuclear Information System (INIS)

    Unidad de Planeacion Minero Energetica, UPME

    1999-01-01

    The planning of the expansion of transport of natural gas system; should keep in mind the changes that are happening in the structure of this industry in the country. In this respect, it is growing the number of actors private present in her, what determines a indicative type planning, whose main objective is to serve as information or guide in decisions of investment involved agents in the maintenance and the amplification of the net of transport for the national supply of natural gas. An indicative plan has objectives different to those of an operative plan of short term. While this last search to establish a program of adjustments to manage commitments of transport and to maintain, this way, the validity of the gas pipeline, The indicative plan of transport is guided to quantify the intensity of the financial effort that is required so that the capacity of the gas pipeline net, responds to the prospective growth of the gas industry. In other words, the indicative plan should contribute to identify the type of works and the one mounts of the investments that the transport of gas system needs in the long term. In this sense, it is important to specify the function objective that will optimize, this precision it should take into account, in our case, the foreseen expansion of the electric sector, because this it depends in good measure of the costs and of the geographical readiness of fuels as the natural gas and the coal. Said otherwise, the function objective that should be optimized involves the expansion of the net of transport of natural gas and the expansion of the generation capacity simultaneously and of the infrastructure of electricity transmission

  5. Transport of neutral solute across articular cartilage: the role of zonal diffusivities.

    Science.gov (United States)

    Arbabi, V; Pouran, B; Weinans, H; Zadpoor, A A

    2015-07-01

    Transport of solutes through diffusion is an important metabolic mechanism for the avascular cartilage tissue. Three types of interconnected physical phenomena, namely mechanical, electrical, and chemical, are all involved in the physics of transport in cartilage. In this study, we use a carefully designed experimental-computational setup to separate the effects of mechanical and chemical factors from those of electrical charges. Axial diffusion of a neutral solute Iodixanol into cartilage was monitored using calibrated microcomputed tomography micro-CT images for up to 48 hr. A biphasic-solute computational model was fitted to the experimental data to determine the diffusion coefficients of cartilage. Cartilage was modeled either using one single diffusion coefficient (single-zone model) or using three diffusion coefficients corresponding to superficial, middle, and deep cartilage zones (multizone model). It was observed that the single-zone model cannot capture the entire concentration-time curve and under-predicts the near-equilibrium concentration values, whereas the multizone model could very well match the experimental data. The diffusion coefficient of the superficial zone was found to be at least one order of magnitude larger than that of the middle zone. Since neutral solutes were used, glycosaminoglycan (GAG) content cannot be the primary reason behind such large differences between the diffusion coefficients of the different cartilage zones. It is therefore concluded that other features of the different cartilage zones such as water content and the organization (orientation) of collagen fibers may be enough to cause large differences in diffusion coefficients through the cartilage thickness.

  6. Case Study: Natural Gas Regional Transport Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Laughlin, M.; Burnham, A.

    2016-08-01

    Learn about Ryder System, Inc.'s experience in deploying nearly 200 CNG and LNG heavy-duty trucks and construction and operation of L/CNG stations using ARRA funds. Using natural gas in its fleet, Ryder mitigated the effects of volatile fuel pricing and reduced lifecycle GHGs by 20% and petroleum by 99%.

  7. Network ownership and optimal tariffs for natural gas transport

    International Nuclear Information System (INIS)

    Hagen, Kaare P.; Kind, Hans Jarle; Sannarnes, Jan Gaute

    2004-11-01

    This paper addresses the issue of national optimal tariffs for transportation of natural gas in a setting where national gas production in its entirety is exported to end-user markets abroad. In a situation where the transportation network is owned altogether by a vertically integrated national gas producer, it is shown that the optimal tariff depends on the ownership structure in the integrated transportation company as well as in the non-facility based gas company. There are two reasons why it is possibly optimal with a mark-up on marginal transportation costs. First, there is a premium on public revenue if domestic taxation is distorting. Second, with incomplete national taxation of rents from the gas sector, the transportation tariffs can serve as a second best way of appropriating rents accruing to foreigners. In a situation where the network is run as a separate entity subject to a rate of return regulation, it will be optimal to discriminate the tariffs between shippers for the usual Ramseyean reasons. (Author)

  8. Panorama 2009 - greenhouse gas emissions and the transport sector

    International Nuclear Information System (INIS)

    2008-01-01

    The fact that the transport sector is growing quickly brings advantages, such as quick access to any geographical location on earth, but also disadvantages: noise, congestion and polluting emissions such as carbon dioxide (CO 2 ), the greenhouse gas (GHG) primarily responsible for global warming. In the effort to bring GHG emissions under control, improving results in the transport sector is a prime long-term objective. What proportion of CO 2 emissions generated at global and national level are due to the road, air, maritime and rail transport sectors, respectively? What mechanisms can be used to reduce GHG emissions in the transport sector at large?

  9. Radio-frequency heating and neutral atom transport in a fluid-magnetohydrodynamic treatment of burning tokamak plasmas

    International Nuclear Information System (INIS)

    Conn, R.W.; Mau, T.K.; Prinja, A.K.

    1983-01-01

    A physical model for the space and time evolution of the primary parameters of ordinary and burning tokamak plasmas is described by employing a fluid plasma treatment coupled to a magnetohydrodynamic equilibrium description, the solution to the appropriate Maxwell equations, and the solution of the linear transport equation describing neutral atom transport in plasmas. The specific problems of plasma heating by ion cyclotron radiofrequency (ICRF) waves and neutral atom transport in the plasma edge and in complicated geometrical components such as divertor channels or pumped limiter structures are analyzed. A theoretical, onedimensional slab model of ICRF heating at ω = 2ω/SUB cD/ is developed and applied to determine the space-time response of tokamak plasmas. Generally, strong single-pass absorption is found for high-density, high (β) plasmas using a low k 11 spectrum (0.05 to 0.1 cm -1 ) although for (β > 1%, electron Landau damping becomes important. Deterministic and Monte Carlo methods to solve the neutral atom transport problem are described. Specific application to determine the spectrum of neutral atoms emerging from the duct of a pump limiter shows it to be hard (mean energy > 20 eV), indicating very incomplete energy thermalization. Uncertainties are identified in the overall problem of dynamic burning plasma analysis caused by the complexity of the problem itself and by uncertainties in fundamental areas such as plasma transport coefficients, stability, and plasma edge physics

  10. Benchmark studies of BOUT++ code and TPSMBI code on neutral transport during SMBI

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.H. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Wang, Z.H., E-mail: zhwang@swip.ac.cn [Southwestern Institute of Physics, Chengdu 610041 (China); Guo, W., E-mail: wfguo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Ren, Q.L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Sun, A.P.; Xu, M.; Wang, A.K. [Southwestern Institute of Physics, Chengdu 610041 (China); Xiang, N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

    2017-06-09

    SMBI (supersonic molecule beam injection) plays an important role in tokamak plasma fuelling, density control and ELM mitigation in magnetic confinement plasma physics, which has been widely used in many tokamaks. The trans-neut module of BOUT++ code is the only large-scale parallel 3D fluid code used to simulate the SMBI fueling process, while the TPSMBI (transport of supersonic molecule beam injection) code is a recent developed 1D fluid code of SMBI. In order to find a method to increase SMBI fueling efficiency in H-mode plasma, especially for ITER, it is significant to first verify the codes. The benchmark study between the trans-neut module of BOUT++ code and the TPSMBI code on radial transport dynamics of neutral during SMBI has been first successfully achieved in both slab and cylindrical coordinates. The simulation results from the trans-neut module of BOUT++ code and TPSMBI code are consistent very well with each other. Different upwind schemes have been compared to deal with the sharp gradient front region during the inward propagation of SMBI for the code stability. The influence of the WENO3 (weighted essentially non-oscillatory) and the third order upwind schemes on the benchmark results has also been discussed. - Highlights: • A 1D model of SMBI has developed. • Benchmarks of BOUT++ and TPSMBI codes have first been finished. • The influence of the WENO3 and the third order upwind schemes on the benchmark results has also been discussed.

  11. On the use of diffusion synthetic acceleration in parallel 3D neutral particle transport calculations

    International Nuclear Information System (INIS)

    Brown, P.; Chang, B.

    1998-01-01

    The linear Boltzmann transport equation (BTE) is an integro-differential equation arising in deterministic models of neutral and charged particle transport. In slab (one-dimensional Cartesian) geometry and certain higher-dimensional cases, Diffusion Synthetic Acceleration (DSA) is known to be an effective algorithm for the iterative solution of the discretized BTE. Fourier and asymptotic analyses have been applied to various idealizations (e.g., problems on infinite domains with constant coefficients) to obtain sharp bounds on the convergence rate of DSA in such cases. While DSA has been shown to be a highly effective acceleration (or preconditioning) technique in one-dimensional problems, it has been observed to be less effective in higher dimensions. This is due in part to the expense of solving the related diffusion linear system. We investigate here the effectiveness of a parallel semicoarsening multigrid (SMG) solution approach to DSA preconditioning in several three dimensional problems. In particular, we consider the algorithmic and implementation scalability of a parallel SMG-DSA preconditioner on several types of test problems

  12. Pressure in the natural gas pipe. Coherence between tariffs for natural gas transport, and congestion in the Netherlands

    International Nuclear Information System (INIS)

    Boots, M.G.; De Joode, J.; Lise, W.

    2005-11-01

    Using GASTALE (Gas mArket System for Trade Analysis in a Liberalizing Europe), a comprehensive computational game theoretic model of the European gas market, the Energy research Centre of the Netherlands (ECN) conducted at the request of Gas Transportation Services (GTS) a study on the relationship between gas transport tariffs, the demand for gas transport and possible re-routing of gas flows in Northwestern Europe. We find that lowering the average Dutch transport tariff compared to the average German transport tariff induces a re-routing of gas flows from the German network to the Dutch network. In periods of high gas demand, such as the peak winter season, the lower transport tariffs lead to a high potential demand for gas transport which cannot be fulfilled by the limited capacity of the Dutch gas transport network. This will probably even lead to congestion in the Dutch network as a 'first-come first-served' regime is currently applied in the Netherlands. So Dutch gas transport tariffs being out of line with the gas transport tariffs neighbouring countries, implies that there is a real chance that transit flows are crowding-out gas flows destined for Dutch final consumers of gas. Hence, the security of gas supply for the Netherlands is seriously threatened. These findings are robust for variations in the model assumptions as shown by a number of sensitivity analyses [nl

  13. Momentum, heat, and neutral mass transport in convective atmospheric pressure plasma-liquid systems and implications for aqueous targets

    NARCIS (Netherlands)

    Lindsay, A.; Anderson, C.; Slikboer, E.T.; Shannon, S.; Graves, D.

    2015-01-01

    There is a growing interest in the study of plasma-liquid interactions with application to biomedicine, chemical disinfection, agriculture, and other fields. This work models the momentum, heat, and neutral species mass transfer between gas and aqueous phases in the context of a streamer discharge;

  14. Feed gas contaminant control in ion transport membrane systems

    Science.gov (United States)

    Carolan, Michael Francis [Allentown, PA; Minford, Eric [Laurys Station, PA; Waldron, William Emil [Whitehall, PA

    2009-07-07

    Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

  15. Transport Calculations for the reference configuration under neutral bean injection in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Castejon, F.; Liniers, M.

    1999-01-01

    Transport calculations for the Reference Configuration under Neutral Beam Injection in TJ-II are discussed. For all these analysis the Transport Code PROCTR has been used but, in reason of the complex geometry of TJ-II, some modifications to the code have been needed, not only for the absorption, losses and deposition radial profile evaluations, but also for the treatment of the transition between ECRH and NBI or the fit of Transport Coefficients to the different Scaling Laws. The attained centralβ values for high density ( central value around 11 x 10''13 cm''3), in steady, range between a minimum of 1.9% for the GRB law up to 3.6% or 4.2% for those laws that show an explicit dependence with the rotational transform (ISS and LGS), with an intermediate value of 2.8% for the LHD case. Global energy confinement times range between 3.9 and 8.8 ms for the two extreme cases and 5.6 ms for LHD. As well ions as electrons are clearly in the plateau regime, in contrast to the ECRH phase where the electrons are well inside the 1/ν regime, dominated by helical ripple effects. The effect of impurities is to decrease slightly the absorption and the attainable β levels, but only for Zeff values higher than 4 this degradation becomes important. For the stationary state the density remains always below the semiempirical limit, independently of the Zeff value. Even along the first stages of injection, where absorption can be rather low, the limit is not reached, at least for Zeff < 4, so that radioactive collapse along this critical phase should not to be expected. (Author) 14 refs

  16. Generalized hydrodynamic transport in lattice-gas automata

    Science.gov (United States)

    Luo, Li-Shi; Chen, Hudong; Chen, Shiyi; Doolen, Gary D.; Lee, Yee-Chun

    1991-01-01

    The generalized hydrodynamics of two-dimensional lattice-gas automata is solved analytically in the linearized Boltzmann approximation. The dependence of the transport coefficients (kinematic viscosity, bulk viscosity, and sound speed) upon wave number k is obtained analytically. Anisotropy of these coefficients due to the lattice symmetry is studied for the entire range of wave number, k. Boundary effects due to a finite mean free path (Knudsen layer) are analyzed, and accurate comparisons are made with lattice-gas simulations.

  17. Gas transport during in vitro and in vivo preclinical testing of inert gas therapies

    Directory of Open Access Journals (Sweden)

    Ira Katz

    2016-01-01

    Full Text Available New gas therapies using inert gases such as xenon and argon are being studied, which require in vitro and in vivo preclinical experiments. Examples of the kinetics of gas transport during such experiments are analyzed in this paper. Using analytical and numerical models, we analyze an in vitro experiment for gas transport to a 96 cell well plate and an in vivo delivery to a small animal chamber, where the key processes considered are the wash-in of test gas into an apparatus dead volume, the diffusion of test gas through the liquid media in a well of a cell test plate, and the pharmacokinetics in a rat. In the case of small animals in a chamber, the key variable controlling the kinetics is the chamber wash-in time constant that is a function of the chamber volume and the gas flow rate. For cells covered by a liquid media the diffusion of gas through the liquid media is the dominant mechanism, such that liquid depth and the gas diffusion constant are the key parameters. The key message from these analyses is that the transport of gas during preclinical experiments can be important in determining the true dose as experienced at the site of action in an animal or to a cell.

  18. Measurement of gas transport properties for chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

    1996-12-01

    In the chemical vapor infiltration (CVI) process for fabricating ceramic matrix composites (CMCs), transport of gas phase reactant into the fiber preform is a critical step. The transport can be driven by pressure or by concentration. This report describes methods for measuring this for CVI preforms and partially infiltrated composites. Results are presented for Nicalon fiber cloth layup preforms and composites, Nextel fiber braid preforms and composites, and a Nicalon fiber 3-D weave composite. The results are consistent with a percolating network model for gas transport in CVI preforms and composites. This model predicts inherent variability in local pore characteristics and transport properties, and therefore, in local densification during processing; this may lead to production of gastight composites.

  19. A transmission/escape probabilities model for neutral particle transport in the outer regions of a diverted tokamak

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1992-12-01

    A new computational model for neutral particle transport in the outer regions of a diverted tokamak plasma chamber is presented. The model is based on the calculation of transmission and escape probabilities using first-flight integral transport theory and the balancing of fluxes across the surfaces bounding the various regions. The geometrical complexity of the problem is included in precomputed probabilities which depend only on the mean free path of the region

  20. Gas transport and subsoil pore characteristics

    DEFF Research Database (Denmark)

    Berisso, Feto Esimo; Schjønning, Per; Keller, Thomas

    2013-01-01

    Arrangements of elementary soil particles during soil deposition and subsequent biological and physical processes in long-term pedogenesis are expected to lead to anisotropy of the non-tilled subsoil pore system. Soil compaction by agricultural machinery is known to affect soil pore characteristics...... were sampled in vertical and horizontal directions from 0.3, 0.5, 0.7 and 0.9 m depth (the two lower depths only in Sweden). In the laboratory, water retention, air permeability (ka) and gas diffusivity (Ds/D0) were determined. For the sandy clay loam, morphological characteristics of pores (effective......). In the sandy clay loam soil, dB and nB displayed significant anisotropy (FAcharacteristics because of its origin...

  1. A reassessment of the blood-brain barrier transport of large neutral amino acids during acute systemic inflammation in humans

    DEFF Research Database (Denmark)

    Dahl, Rasmus H; Berg, Ronan M G; Taudorf, Sarah

    2018-01-01

    We reassessed data from a previous study on the transcerebral net exchange of large neutral amino acids (LNAAs) using a novel mathematical model of blood-brain barrier (BBB) transport. The study included twelve healthy volunteers who received a 4-h intravenous lipopolysaccharide (LPS) infusion...

  2. Greenhouse Gas Emissions Trading for the Transport Sector

    International Nuclear Information System (INIS)

    Holmgren, Kristina; Belhaj, Mohammed; Gode, Jenny; Saernholm, Erik; Zetterberg, Lars; Aahman, Markus

    2006-12-01

    In this study we have analysed different options to apply emissions trading for greenhouse gas emissions to the transport sector. The main focus has been on the EU transport sector and the possibility to include it in the current EU ETS in the trading period beginning in 2013. The purpose was to study how different alternatives will affect different actors. Focus has been on three sub-sectors; road transport, aviation and shipping. The railway sector has only been treated on a general level. The study includes the following three parts: 1. An economic analysis of the consequences of greenhouse gas emissions trading for the transport sector including an analysis of how the total cost for reaching an emission target will be affected by an integrated emissions trading system for the transport sector and the industry (currently included sectors) compared to separate systems for the sectors, 2. An analysis of design possibilities for the different sub-sectors. Discussion of positive and negative aspects with different choices of design parameters, such as trading entity, covered greenhouse gases, allocation of emission allowances and monitoring systems, 3. Examination of the acceptance among different actors for different options of using greenhouse gas emissions trading in the transport sector. When setting up an emissions trading scheme there are a number of design parameters that have to be analysed in order to find an appropriate system, with limited administrative and transaction costs and as small distortions as possible to competitiveness

  3. Neutral interstellar gas toward epsilon persei: H I, H2, D I, N I, O I

    International Nuclear Information System (INIS)

    Vidal, A.; Ferlet, R.; Laurent, C.; York, D.G.

    1982-01-01

    The study of the interstellar medium toward epsilon Per, a moderately reddened (E/sub B/-V = 0.1) B0.5 star, through the analysis of H I, D I, H 2 , N I, O I, and Ar I absorption features, revealed the following structure of the line of sight: (1) a main interstellar, cold (Tapprox.100 K; b = 2.9 km s -1 ) component, (2) a weak (approx.1% of the main one) probably cold component, and (3) a weak (also approx.1% of the main one) and hot component (Tapprox.8000 K). All three components have normal abundances. Comparison with ground-based observations or other UV studies reveals the presence on the line of sight of an H II region not detected in the neutral species observed in this study. High-velocity H I gas is also detected, located either in the interstellar medium or very likely in the stellar wind for the blue-shifted components. One of these features is blended with the deuterium lines and therefore obscures our D/H evaluation. All we can say is that the data are compatible with a D/H ratio equal to 1.5 x 10 -5 . This blended feature proved to vary by at least a factor of 3 in column density within few hours, a result which sustains our interpretation of the stellar wind origin of the blueshifted high-velocity H I component. However, the alternative interpretation of a high D/H (approx.10 -4 ) value is also compatible with our data

  4. Unconventional Gas. A Game Changer for Transport Too?

    International Nuclear Information System (INIS)

    Boncourt, Maite de

    2011-01-01

    A new technology trend, the development of natural gas vehicles, is emerging in the transport sector. While not new this technology is now being simultaneously revived by the discovery of significant amounts of unconventional gas, by the rise of oil prices, and by the decreased confidence in the sustainability of nuclear technology (and subsequent rising electricity prices in Europe). Natural gas could provide a path to a lower carbon intensive transport sector in both developed and developing countries. Gas is cheaper and less polluting than oil. It emits significantly less local pollutants than diesel and less CO 2 than gasoline. Historically present in Italy, South America, Iran and Pakistan natural gas vehicles are emerging in other countries: in some European countries, in the United States, in the Chinese provinces of Shaanxi and Henan, and in India. Asia and developing countries are expected to be responsible for a large share of the car market growth in the next years and consequently for a significant share of transport CO 2 emissions. The adoption of a given technology there could impact global markets and global CO 2 emissions significantly. While the trend is still loose, this paper responds to the possibility that this technology will expand: what would it imply? would it compete with the development of the electric vehicle? is it desirable? It appears that the advantages of natural gas vehicles are not as clear cut as they seem. Environmentally, they are beneficial only to countries with little -if no- CO 2 emissions standards. Several issues including the development of costly infrastructures are likely to raise costs. Natural gas vehicles development could also slow down the roll out of electric vehicles, hence delaying hopes of smoothing the integration of renewables into the power grid through the use of car batteries' storage capacity. But the main concern is the availability of cheap gas itself, on the basis of which this technology shift could

  5. Reducing greenhouse gas emissions from u.s. transportation

    Science.gov (United States)

    2010-01-01

    This report examines the prospects for substantially reducing the greenhouse gas (GHG) emissions from the U.S. transportation sector, which accounts for 27 percent of the GHG emissions of the entire U.S. economy and 30 percent of the world's transpor...

  6. Development Of A Parallel Performance Model For The THOR Neutral Particle Transport Code

    Energy Technology Data Exchange (ETDEWEB)

    Yessayan, Raffi; Azmy, Yousry; Schunert, Sebastian

    2017-02-01

    The THOR neutral particle transport code enables simulation of complex geometries for various problems from reactor simulations to nuclear non-proliferation. It is undergoing a thorough V&V requiring computational efficiency. This has motivated various improvements including angular parallelization, outer iteration acceleration, and development of peripheral tools. For guiding future improvements to the code’s efficiency, better characterization of its parallel performance is useful. A parallel performance model (PPM) can be used to evaluate the benefits of modifications and to identify performance bottlenecks. Using INL’s Falcon HPC, the PPM development incorporates an evaluation of network communication behavior over heterogeneous links and a functional characterization of the per-cell/angle/group runtime of each major code component. After evaluating several possible sources of variability, this resulted in a communication model and a parallel portion model. The former’s accuracy is bounded by the variability of communication on Falcon while the latter has an error on the order of 1%.

  7. Pulse radiolysis of alkanes in the gas-phase, ion-molecule reactions and neutralization mechanisms of hydrocarbon ions

    International Nuclear Information System (INIS)

    Ausloos, P.

    1975-01-01

    A discussion is presented of the fate of unreactive hydrocarbon ions in various selected gaseous systems. It is shown that experiments performed with the high radiation dose rates obtained in pulse radiolysis experiments have several advantages over conventional low dose rate experiments for the elucidation of the mechanism of homogeneous neutralization of unreactive hydrocarbon ions. This is so because the charged species has a much shorter lifetime with respect to neutralization under high dose rate (pulse radiolysis) conditions, so that the reaction of the ions with minor impurities or accumulated products is much less probable than in low dose rate experiments. It is further shown through a few examples, that quantitative information about the rate contants of neutralization events and ion-molecule reactions can be obtained when the dose rate is high enough for neutralization and chemical reaction to be in competition. Once reliable rate constants for neutralization and ion-molecule reactions are derived, one can obtain a quantitative evaluation of the products which will by formed in the pulse radiolysis of a hydrocarbon gas mixture from a computer calculation. (author)

  8. Gas-Phase Energetics of Actinide Oxides: An Assessment of Neutral and Cationic Monoxides and Dioxides from Thorium to Curium

    Science.gov (United States)

    Marçalo, Joaquim; Gibson, John K.

    2009-09-01

    An assessment of the gas-phase energetics of neutral and singly and doubly charged cationic actinide monoxides and dioxides of thorium, protactinium, uranium, neptunium, plutonium, americium, and curium is presented. A consistent set of metal-oxygen bond dissociation enthalpies, ionization energies, and enthalpies of formation, including new or revised values, is proposed, mainly based on recent experimental data and on correlations with the electronic energetics of the atoms or cations and with condensed-phase thermochemistry.

  9. 2009 South American benchmarking study: natural gas transportation companies

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Nathalie [Gas TransBoliviano S.A. (Bolivia); Walter, Juliana S. [TRANSPETRO, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    In the current business environment large corporations are constantly seeking to adapt their strategies. Benchmarking is an important tool for continuous improvement and decision-making. Benchmarking is a methodology that determines which aspects are the most important to be improved upon, and it proposes establishing a competitive parameter in an analysis of the best practices and processes, applying continuous improvement driven by the best organizations in their class. At the beginning of 2008, GTB (Gas TransBoliviano S.A.) contacted several South American gas transportation companies to carry out a regional benchmarking study in 2009. In this study, the key performance indicators of the South American companies, whose reality is similar, for example, in terms of prices, availability of labor, and community relations, will be compared. Within this context, a comparative study of the results, the comparative evaluation among natural gas transportation companies, is becoming an essential management instrument to help with decision-making. (author)

  10. Natural gas in road transport in New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Maiden, C J

    1986-01-01

    This paper describes how the products of New Zealand's natural gas fields are to be used in the transport sector to reduce oil imports. As a result of such developments New Zealand will be about 53% self-sufficient in transport fuels in 1986/1987. This self-sufficiency will be made up as follows: 25% from condensate from gas fields, 18% from synthetic gasoline, 5% from the use of compressed natural gas (CNG) and liquefied petroleum gas (LPT) in vehicles and 5% from indigenous oil supplies. History and status of the CNG Programme are outlined. Government has set a goal of 200,000 vehicles operating on CNG by 1990 and, at present, about 80,000 vehicles are powered by natural gas. The Gas to Gasoline project is described in some detail. New Zealand's imports of crude oil and oil products for 1986/1987 are forecast to total 1,900,000 tonnes, less than one-half of the 4,257,000 tonnes of comparable imports in 1973/1974.

  11. Greenhouse gas emissions from heavy-duty natural gas, hybrid, and conventional diesel on-road trucks during freight transport

    Science.gov (United States)

    Quiros, David C.; Smith, Jeremy; Thiruvengadam, Arvind; Huai, Tao; Hu, Shaohua

    2017-11-01

    Heavy-duty on-road vehicles account for 70% of all freight transport and 20% of transportation-sector greenhouse gas (GHG) emissions in the United States. This study measured three prevalent GHG emissions - carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) - from seven heavy-duty vehicles, fueled by diesel and compressed natural gas (CNG), and compliant to the MY 2007 or 2010 U.S. EPA emission standards, while operated over six routes used for freight movement in California. Total combined (tractor, trailer, and payload) weights were 68,000 ± 1000 lbs. for the seven vehicles. Using the International Panel on Climate Change (IPCC) radiative forcing values for a 100-year time horizon, N2O emissions accounted for 2.6-8.3% of total tailpipe CO2 equivalent emissions (CO2-eq) for diesel vehicles equipped with Diesel Oxidation Catalyst, Diesel Particulate Filter, and Selective Catalytic Reduction system (DOC + DPF + SCR), and CH4 emissions accounted for 1.4-5.9% of CO2-eq emissions from the CNG-powered vehicle with a three-way catalyst (TWC). N2O emissions from diesel vehicles equipped with SCR (0.17-0.30 g/mi) were an order of magnitude higher than diesel vehicles without SCR (0.013-0.023 g/mi) during highway operation. For the vehicles selected in this test program, we measured 11-22% lower CO2-eq emissions from a hybrid compared to conventional diesel vehicles during transport over lower-speed routes of the freight transport system, but 20-27% higher CO2-eq emissions during higher-speed routes. Similarly, a CNG vehicle emitted up to 15% lower CO2-eq compared to conventional diesel vehicles over more neutral-grade highway routes, but emitted up to 12% greater CO2-eq emissions over routes with higher engine loads.

  12. Quantities of natural gas transported in January-December 2009

    International Nuclear Information System (INIS)

    2010-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2009: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  13. Gas transport into a cavitation bubble during the explosion

    International Nuclear Information System (INIS)

    Oldenziel, D.M.

    1976-01-01

    When considering cavitation bubbles exploding from small stream nuclei the surface tension plays an important role, and mostly negative pressures exist in the surroundings of such a bubble. During the short explosion time, the gas and vapor pressure in the bubble plays no important role in the dynamic process. The high radial velocity of the bubble wall introduces a steep gradient in the concentration of dissolved air near it, which results in some enforced gas transport into the bubble. During the bubble implosion it is necessary to take into account the amount of gas in the bubble, as it certainly plays an important role in exploring the cavitation erosion. In this survey the solution of a mathematical model for the gas diffusion process is compared with some experimental results

  14. Quantities of natural gas transported in August-December 2007

    International Nuclear Information System (INIS)

    2008-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the available monthly key figures of GRTgaz activity from August to December 2007: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  15. Reducing Greenhouse Gas Emissions in Transport: All in One Basket?

    Directory of Open Access Journals (Sweden)

    Nicholas Rivers

    2018-02-01

    Full Text Available Analysis after analysis has shown consistently that if policy-makers aiming to meet climate goals are looking for the most-efficient, least-distortionary way to target emissions growth, there is simply nothing better than abandoning all emissions regulations except for one: A straight, revenue-neutral carbon tax. Nothing works through more channels, at a lower cost. Alas, policy-makers are not always looking for the most-efficient, least-distortionary way to target emissions growth. That’s because many of those same analyses show that in order to reach emissions targets, the price on carbon would have to be so punitive as to be politically unbearable, raising the price of gasoline, for example, by about a dollar a litre. That leads politicians to mix in other policies that are less visible to the consumer but also less efficient, less effective and more expensive in abating carbon dioxide. The recently negotiated Pan-Canadian Framework on Clean Growth and Climate Change intends to follow that model, relying on a blend of different policies to help reach Canada’s Paris climate targets. But while the government seems therefore determined to rule out the possibility of a nothing-but-a-carbon-tax plan, it is possible, through the careful application of just the right sort of emission-reduction approaches, to reduce the costs of abatement in a key policy target — namely, road transportation — to a level that at least approaches the lower cost of a carbon tax. The government will likely consider several options in trying to reduce emissions from road transportation. Typical tools include requiring manufacturers to meet standards for new vehicles that mandate fuel economy and greenhouse gas emissions; gasoline taxes; taxes on emissions-intensive vehicles; subsidies for low-emission or zero-emission vehicles; and subsidies for public transit. Indications are that a low-carbon fuel standard (LCFS will play a significant role in the Pan

  16. Characterization of Nanoscale Gas Transport in Shale Formations

    Science.gov (United States)

    Chai, D.; Li, X.

    2017-12-01

    Non-Darcy flow behavior can be commonly observed in nano-sized pores of matrix. Most existing gas flow models characterize non-Darcy flow by empirical or semi-empirical methods without considering the real gas effect. In this paper, a novel layered model with physical meanings is proposed for both ideal and real gas transports in nanopores. It can be further coupled with hydraulic fracturing models and consequently benefit the storage evaluation and production prediction for shale gas recovery. It is hypothesized that a nanotube can be divided into a central circular zone where the viscous flow behavior mainly exists due to dominant intermolecular collisions and an outer annular zone where the Knudsen diffusion mainly exists because of dominant collisions between molecules and the wall. The flux is derived based on integration of two zones by applying the virtual boundary. Subsequently, the model is modified by incorporating slip effect, real gas effect, porosity distribution, and tortuosity. Meanwhile, a multi-objective optimization method (MOP) is applied to assist the validation of analytical model to search fitting parameters which are highly localized and contain significant uncertainties. The apparent permeability is finally derived and analyzed with various impact factors. The developed nanoscale gas transport model is well validated by the flux data collected from both laboratory experiments and molecular simulations over the entire spectrum of flow regimes. It has a decrease of as much as 43.8% in total molar flux when the real gas effect is considered in the model. Such an effect is found to be more significant as pore size shrinks. Knudsen diffusion accounts for more than 60% of the total gas flux when pressure is lower than 0.2 MPa and pore size is smaller than 50 nm. Overall, the apparent permeability is found to decrease with pressure, though it rarely changes when pressure is higher than 5.0 MPa and pore size is larger than 50 nm.

  17. International transport of incandescent gas mantles - an incident

    International Nuclear Information System (INIS)

    Singh, Khaidem R.K.

    2004-01-01

    Consumer products, though contain small quantities of radioactive material, are designed and manufactured with reference to prescribed safety standards; and supplied for use in public domain. On the basis of the nature of the exposures associated with such practices, which are quite low, the Regulatory Authority exempts the practices from many of the regulatory requirements. As they are inherently safe for handling, transporting and use, they are exempted from some of the requirements under the provisions of the regulations on the transport of radioactive material. Though the basic meaning and purpose of a radioactivity-based consumer product are similar to other commodities, there is a need to transport the former as per the regulations for safe transport of radioactive material till the product reaches at end user. The strict adherence to the transport regulations during transport of the radioactivity-based consumer product would ensure smooth carriage particularly in international arena. On the basis of an incident that happened during the transport of consumer products, this paper analyzes the provisions relating to radioactivity-based consumer products as envisaged in the basic safety standards of IAEA and their transport, particularly for natural thorium based consumer product gas mantles. (author)

  18. Research on gas transport in chimneys: a progress report

    International Nuclear Information System (INIS)

    Hearst, J.R.

    1986-01-01

    The results of the AGRINI and TIERRA experiments have led us to study three general topics: collapse phenomenology, CO 2 content measurement, and gas transport in chimneys. Our results so far are fragmentary, but we have been able to come to some tentative conclusions: (1) a layer of strong material between depths of 24 and 32 m, and perhaps some relatively strong material deeper, may have caused the AGRINI crater shape. This layer was absent at the nearby LABAN and CROWDIE events. We were unable to locate the layer with a surface penetrometer or surface seismic methods, but it may be possible to measure strength vs depth in situ by examining the penetration depth of a projectile. (2) We can probably improve our knowledge of the in situ CO 2 content by calibrating a commercial carbon/oxygen logging system for NTS conditions. (3) It is possible to measure the response of the gas in a chimney to changes in atmospheric pressure. There can be significantly different gas transport in chimneys with the same pressure response, depending on the porosity and the distribution of the porosity. It is possible to perform an inexpensive experiment to study the gas transport in an existing chimney

  19. Particle transport and gas feed during gun injection

    International Nuclear Information System (INIS)

    Fowler, T K.

    1999-01-01

    It is shown that ion and neutral transport during gun injection tends to equalize the density in the spheromak to that in the open-line current channel. Since a gun operating at or near the ion saturation current requires a minimum density, because of transport these gun requirements also determine a minimum density in the spheromak that increases as the field increases. Hence attaining high fields by gun injection sets lower limits on the density, which in turn limits the temperature of the plasma and increases its ohmic resistance. Estimates of these effects are given using 0-D models calibrated to CTX, as guidance to 2-D UEDGE calculations in progress. For gun power levels in SSPX and the Pulsed Spheromak reactor, we find that buildup persists to the highest field levels of interest

  20. Sodium-coupled neutral amino acid (System N/A) transporters of the SLC38 gene family.

    Science.gov (United States)

    Mackenzie, Bryan; Erickson, Jeffrey D

    2004-02-01

    The sodium-coupled neutral amino acid transporters (SNAT) of the SLC38 gene family resemble the classically-described System A and System N transport activities in terms of their functional properties and patterns of regulation. Transport of small, aliphatic amino acids by System A subtypes (SNAT1, SNAT2, and SNAT4) is rheogenic and pH sensitive. The System N subtypes SNAT3 and SNAT5 also countertransport H(+), which may be key to their operation in reverse, and have narrower substrate profiles than do the System A subtypes. Glutamine emerges as a favored substrate throughout the family, except for SNAT4. The SLC38 transporters undoubtedly play many physiological roles including the transfer of glutamine from astrocyte to neuron in the CNS, ammonia detoxification and gluconeogenesis in the liver, and the renal response to acidosis. Probing their regulation has revealed additional roles, and recent work has considered SLC38 transporters as therapeutic targets in neoplasia.

  1. Cross sections and transport properties for Na+ in (DXE gas

    Directory of Open Access Journals (Sweden)

    Nikitović Željka D.

    2016-01-01

    Full Text Available In this work we select most probable reactions of alkali metal ion Na+ with dimethoxyethane (DXE molecule. Appropriate gas phase enthalpies of formation for the products were used to calculate scattering cross section as a function of kinetic energy with Denpoh-Nanbu theory. Calculated cross sections were compared with existing experimental results obtained by guided ion beam tandem mass spectrometry. Three body association reactions of ions with DXE is studied and compared to experimental results. Calculated cross sections were used to obtain transport parameters for alkali metal ion in DXE gas. [Projekat Ministarstva nauke Republike Srbije, br. ON 171037 i br. III 410011

  2. New benchmark for basic and neutral nitrogen compounds speciation in middle distillates using comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Adam, Frédérick; Bertoncini, Fabrice; Brodusch, Nicolas; Durand, Emmanuelle; Thiébaut, Didier; Espinat, Didier; Hennion, Marie-Claire

    2007-04-27

    This paper reports an analytical method for the comprehensive two-dimensional gas chromatography (GC x GC) separation and identification of nitrogen compounds (N-compounds) in middle distillates according to their types (basicity). For the evaluation of the best chromatographic conditions, a non-polar x polar approach was chosen. The impact of the second dimension (stationary phase and column length) on the separation of basic and neutral N-compounds was evaluated by mean of two-dimensional resolution. This study revealed that the implementation of polar secondary column having free electron pairs improves drastically the separation of N-compounds. Indeed, the presence of permanent dipole-permanent dipole interactions between neutral N-compounds and the stationary phase was enlightened. The comparison of two different nitrogen chemiluminescence detectors (NCD) was also evaluated for GC x GC selective monitoring of N-compounds. Owing to higher resolution power and enhanced sensitivity achieved using developed chromatographic and detection conditions, it was possible to identify univocally and to quantitate N-compounds (i) by class of compounds and (ii), within a class, by carbon number. Finally, quantitative comparison of GC x GC-NCD with conventional gas chromatography illustrates the benefits of GC x GC leading to an excellent correlation with results obtained by American Society for Testing Materials (ASTM) methods for the determination of basic/neutral nitrogen ratio in diesel samples.

  3. Selected Topics on Mass Transport in Gas-solid Interactions

    DEFF Research Database (Denmark)

    Somers, Marcel A.J.

    2004-01-01

    The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion-controlled d......The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion...... on the kinetics of phenomena in the solid state. Various experimental techniques were applied to investigate these phenomena; it is however beyond the scope of the present article to treat experimental conditions in detail. The interested reader is referred to the original work for in depth discussions...

  4. Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.; Nieto Delgado, Cesar; Logan, Bruce E.

    2013-01-01

    Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 C to improve their performance as oxygen reduction catalysts in neutral p

  5. Transport of a relativistic electron beam through hydrogen gas

    International Nuclear Information System (INIS)

    Haan, P. de.

    1981-01-01

    In this thesis the author describes the transport properties of an electron beam through vacuum and through hydrogen gas with pressure ranging from 25 to 1000 Pa. Maximum beam energy and current are 0.8 MeV and 6 kA, respectively. The pulse length is around 150 ns. A description is given of the experimental device. Also the diagnostics for probing the beam and the plasma, produced by the beam, are discussed, as well as the data acquisition system. The interaction between the beam and hydrogen gas with a pressure around 200 Pa is considered. A plasma with density around 10 19 m -3 is produced within a few nanoseconds. Measurements yield the atomic hydrogen temperature, electron density, beam energy loss, and induced plasma current and these are compared with the results of a model combining gas ionization and dissociation, and turbulent plasma heating. The angular distribution of the beam electrons about the magnetic field axis is discussed. (Auth.)

  6. Managing change : natural gas transportation to the eastern toll zone

    International Nuclear Information System (INIS)

    Valiante, U.

    2001-01-01

    The Cogenerators Alliance includes Ontario's largest end-use natural gas consumers, Tractebel Power, Westcoast Power, Lake Superior Power, TransAlta Energy, Cardinal Power of Canada and Whitby Cogeneration. Together, they represent 157,798 GJ/day contracted volume. This paper focused on the changing face of the natural gas industry in North America with closer economic ties between Canada, the United States and Mexico in a competitive energy market. The role of Alliance Pipeline in transporting natural gas to markets and the implication of regulation and toll increases were also discussed. It was noted that there is a need for regulatory changes to provide existing pipelines with the appropriate tools needed to ensure the competitive environment will function effectively. tabs., figs

  7. Contracts Take or Pay, for supply and transport of gas

    International Nuclear Information System (INIS)

    Velasquez Bermudez, Jesus Maria

    2000-01-01

    The present article has as objective to study the effect that has the contract of supply and of transport of gas that subscribe generators agents of the electric sector with the agents of the market of the gas. The article concentrates on the study of the denominated contracts take or pay. Initially the modeling is analyzed to include the effect of the contracts of gas in the mathematical models that are used to support the works of planning. Later on is studied of optimal form to determining the prices in spot markets of the industries associated to the contracts. Finally is presented the methodology and controlled experiments that allow to identify and to quantify the macro economic effect of the contracts

  8. 4. report of study group 6.3. Gas for transportation - gas vehicles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The report at hand has been compiled by the International Gas Union Study Group 6.3, which included representatives of 12 different countries. Currently there are about 5.5 million gas vehicles in the world. Of the world vehicle population, that equals less than 1 %. However, just recently in many countries there seem to be new, very rapid developments regarding gas vehicles, as both local and national governments are becoming increasingly aware of exhaust emissions, energy efficiency and security, and the possibilities offered by alternative fuels. This report is intended to give examples and ideas for the gas industry regarding business opportunities in the transportation sector. The principal goal of the report is to provide the reader a thorough picture of the current state-of-the art technology and development trends regarding use of gaseous fuels in the road transportation sector. Thus, the report includes information on technical topics such as different gases, engines, fuel systems, vehicles, and refueling infrastructure. It also addresses the market situation, including legislative and fiscal issues as well as customer awareness issues. The ideas and future prospects, which are compiled in the outlook and conclusion sections, present business opportunities for the participation of the gas industry as an energy provider in the transportation sector. (author)

  9. Possibilities of using liquefied oil gas in transport

    Directory of Open Access Journals (Sweden)

    A. Kuprys

    2009-03-01

    Full Text Available The trends of the input of an alternative type of fuel in the transport system of the European Union are analysed. Taking into account the measures of promoting liquefied petroleum gas (LPG consumption in road transport, a bundle of specific variables was analysed to understand the consumers for making decision to use LPG in cars. It is revealed that the obtained models enable to evaluate the behaviour of consumers and conditioning transition to using an alternative type of fuel in transport industry. The proposed models were assessed conducting statistic and sensitivity analysis. The pay-off of the additional equipment of the car was analysed considering the driven distance with an alternative type of fuel. The pay-off analysis of supplementary equipment depending on the ratio of standard and alternative fuel prices is presented.

  10. Liquid water transport mechanism in the gas diffusion layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, P.; Wu, C.W. [State Key Laboratory of Structure Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China)

    2010-03-01

    We developed an equivalent capillary model of a microscale fiber-fence structure to study the microscale evolution and transport of liquid in a porous media and to reveal the basic principles of water transport in gas diffusion layer (GDL). Analytical solutions using the model show that a positive hydraulic pressure is needed to drive the liquid water to penetrate through the porous GDL even consisting of the hydrophilic fibers. Several possible contributions for the water configuration, such as capillary pressure, gravity, vapor condensation, wettability and microstructures of the GDL, are discussed using the lattice Boltzmann method (LBM). It is found that the distribution manners of the fibers and the spatial mixed-wettability in the GDL also play an important role in the transport of liquid water. (author)

  11. The role of transportation technologies in reducing greenhouse gas emissions

    International Nuclear Information System (INIS)

    Anon.

    1995-11-01

    The potential role of passenger transportation technologies in reducing greenhouse gas emissions was discussed. The technologies considered in the report were those that affect ground transportation of passengers and were in at least the early stages of development in 1995. They were: (1) technologies to improve the fuel efficiency of cars and light trucks, (2) alternative fuels for internal combustion engines, (3) electric hybrid vehicles, (4) advanced technology transit buses, (5) intelligent transportation systems, (6) high speed rail, and (7) bicycles. For each option, the advantages and disadvantages were described. The feasibility of establishing a high-speed rail system serving Canada's most densely populated region, the Windsor to Quebec City corridor, was discussed. Economic and environmental studies of such a proposal are underway. tabs

  12. Behaviour of the ASDEX pressure gauge at high neutral gas pressure and applications for ITER

    International Nuclear Information System (INIS)

    Scarabosio, A.; Haas, G.

    2008-01-01

    The ASDEX Pressure Gauge is, at present, the main candidate for in-vessel neutral pressure measurement in ITER. Although the APG output is found to saturate at around 15 Pa, below the ITER requirement of 20 Pa. We show, here, that with small modifications of the gauge geometry and potentials settings we can achieve satisfactory behaviour up to 30 Pa at 6 T

  13. Axial transport of fission gas in LWR fuel rods

    International Nuclear Information System (INIS)

    Kinoshita, M.

    1983-01-01

    With regard to fission gas transportation inside the fuel rod, the following three mechanisms are important: (1) a localized and time dependent fission gas release from UO 2 fuel to pellet/clad gap, (2) the consequent gas pressure difference between the gap and the plenum, and (3) the inter-diffusion of initially filled Helium and released fission gas such as Xenon. Among these three mechanisms, the 2nd mechanism would result in the one dimensional flow through P/C gap in the axial direction, while the 3rd would average the local fission gas concentration difference. In this paper, an attempt was made to develop a computerized model, LINUS (LINear flow and diffusion under Un-Steady condition) describing the above two mechanisms, items (2) and (3). The item (1) is treated as an input. The code was applied to analyse short length experimental fuel rods and long length commercial fuel rods. The calculated time evolution of Xe concentration along the fuel column shows that the dilution rate of Xe in commercial fuel rods is much slower than that in short experimental fuel rods. Some other sensitivity studies, such as the effect of pre-pressurization, are also presented. (author)

  14. Field measurements of tracer gas transport by barometric pumping

    International Nuclear Information System (INIS)

    Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

    1994-01-01

    Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ''active'' tracer was driven by a large quantity of injected air; the second ''passive'' tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through ∼1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs

  15. Glovebox with purification and pressure control of the neutral gas atmosphere in closed circuit

    International Nuclear Information System (INIS)

    Cadrot, J.

    1990-01-01

    In the gas main are placed 2 series of specific gas purifiers in parallel. Pressure is controlled with a buffer tank two three way solenoid value upstream and down stream a compressor and a supercharger. A checking board allows continuous monitoring of circuit tightness [fr

  16. Magnetic configuration effects on plasma transport under Neutral Beam Injection at TJ-II (Simulation)

    International Nuclear Information System (INIS)

    Guasp, J.; Fuentes, C.; Liniers, M.

    2001-01-01

    A systematic analysis of magnetic configurations (27 in total), using a Transport model including impurity dynamics and sputtering effects has been done. For small size configurations or those close to rational t values there is radioactive collapse, independently of the external gas puffing (GP) strategy chosen. The reason is the insufficiency of observed power, either by the high shine through losses due to their low radii, or by the increase of fast ion orbit losses near the resonances. For the majority of configurations without collapse, fast ion orbit losses for CO injection (going in the same direction than the toroidal magnetic field) are higher, and in consequence the power absorption and the plasma β achieved are laser, than for the opposite direction. Nevertheless in the region placed just above the main resonances (1/3 and 1/2 per period) this situation reverses. The reasons have been analysed and explained at previous studies. A consequence of this fact is that the optima of confinement for the Counter case are shifted towards higher t values than the CO one, with higher plasma β, except near the resonances. As usual the balanced case is in between. The optima achieving stationary state are very close (and often are coincident) with those lacking that restriction. The best configuration (highest average β for balanced injection, with =1.1% and central value 3.2%, although in this region the results are rather insensitive to configuration and GP strategy. the configurations placed around the 100 4 4 would need also the lowest power entering the torus in order to avoid collapse and to achieve an acceptable NBI absorption level. (Author) 12 refs

  17. Direct measurement of the concentration of metastable ions produced from neutral gas particles using laser-induced fluorescence

    Science.gov (United States)

    Chu, Feng; Skiff, Fred; Berumen, Jorge; Mattingly, Sean; Hood, Ryan

    2017-10-01

    Extensive information can be obtained on wave-particle interactions and wave fields by direct measurement of perturbed ion distribution functions using laser-induced fluorescence (LIF). For practical purposes, LIF is frequently performed on metastables that are produced from neutral gas particles and existing ions in other electronic states. We numerically simulate the ion velocity distribution measurement and wave-detection process using a Lagrangian model for the LIF signal. The results show that under circumstances where the metastable ion population is coming directly from the ionization of neutrals (as opposed to the excitation of ground-state ions), the velocity distribution will only faithfully represent processes which act on the ion dynamics in a time shorter than the metastable lifetime. Therefore, it is important to know the ratio of metastable population coming from neutrals to that from existing ions to correct the LIF measurements of plasma ion temperature and electrostatic waves. In this paper, we experimentally investigate the ratio of these two populations by externally launching an ion acoustic wave and comparing the wave amplitudes that are measured with LIF and a Langmuir probe using a lock-in amplifier. DE-FG02-99ER54543.

  18. Reducing the Green House Gas Emissions from the Transportation Sector

    Directory of Open Access Journals (Sweden)

    Oyewande Akinnikawe

    2010-02-01

    Full Text Available In the United States, two thirds of the carbon monoxide and about one third of carbon dioxide emissions come from the transportation sector. Ways to reduce these emissions in the future include replacing gasoline and diesel by biofuels, or by blend of biofuels with conventional gasoline and diesel, or by compressed natural gas (CNG, or by replacing internal combustion engines by electric motors powered by hydrogen fuel cells or battery-powered electric vehicles recharged from the electric grid. This presentation will review these technologies the fuel production pathways, when they are likely to be available, and by what fraction transportation sector green house gas emissions could be reduced by each. A well-to-wheels (WTW analysis is performed on each vehicle/ fuel technology using the GREET model and the total energy use, the CO 2 emissions, NO x emissions, SO x emissions for the life cycle of the vehicle technologies are calculated. Prospects for reducing foreign oil dependence as well as mitigating green house gases emission from the transportation sector will be considered in the analysis.

  19. Impurity transport studies by means of tracer-encapsulated solid pellet injection in neutral beam heated plasmas on LHD

    International Nuclear Information System (INIS)

    Tamura, N; Sudo, S; Khlopenkov, K V; Kato, S; Sergeev, V Yu; Muto, S; Sato, K; Funaba, H; Tanaka, K; Tokuzawa, T; Yamada, I; Narihara, K; Nakamura, Y; Kawahata, K; Ohyabu, N; Motojima, O

    2003-01-01

    The quantitative properties of impurity transport in large helical device (LHD) plasmas heated by neutral beam injection have been investigated by means of tracer-encapsulated solid pellet (TESPEL) injection. In the case of a titanium (Ti) tracer, the behaviour of the emission lines from the highly ionized Ti impurity, Ti Kα(E He-like ∼ 4.7 keV) and Ti XIX (λ = 16.959 nm), has been observed clearly by a soft x-ray pulse height analyzer and a vacuum ultraviolet spectrometer, respectively. A fairly longer decay time of the Ti Kα emission lines is obtained above the value of a line-averaged electron density, 3.0x10 19 m -3 . The dependence of the behaviour of the Ti tracer impurity on the line-averaged electron density below the value of that, 3.5x10 19 m -3 is in qualitative agreement with the characteristics obtained from the observation of the behaviour of an intrinsic metallic impurity in neutral beam heated plasmas on LHD. In order to estimate the properties of the Ti impurity transport quantitatively, the one-dimensional impurity transport code, MIST has been used. As a result of the transport analysis with the MIST code, even an small inward convection should be necessary to account for the experimental results with the value of the line-averaged electron density, 3.5x10 19 m -3 . In order to examine the experimentally obtained transport coefficients, neoclassical analysis with respect to the radial impurity flux has been performed. The inferred rise of the inward convection cannot be explained solely by neoclassical impurity transport. Therefore, in order to account for the inward convection, the effect of a radial electric field and/or some other effect must be taken into account additionally

  20. Time-Dependent Neutral Particle Transport Benchmarks in Two and Three Dimensions

    International Nuclear Information System (INIS)

    Barry D. Ganapol

    2007-01-01

    The main objective of NEER grant was to generate highly accurate 2D and 3D time-dependent neutral particle intensity maps from 3D pulsed wire sources through integration of the analytical representation of a time-dependent point source

  1. The development of a natural gas transportation logistics management system

    Energy Technology Data Exchange (ETDEWEB)

    Pereira dos Santos, Sidney [Petroleo Brasileiro S.A.-PETROBRAS, Av. Almirante Barroso, 81, 12 andar, Centro, Rio de Janeiro RJ 20031-004 (Brazil); Eugenio Leal, Jose, E-mail: jel@puc-rio.br [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Department of Industrial Engineering, R. Marques de S. Vicente 225, Gavea. Rio de Janeiro RJ 22451-900 (Brazil); Oliveira, Fabricio [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Department of Industrial Engineering, R. Marques de S. Vicente 225, Gavea. Rio de Janeiro RJ 22451-900 (Brazil)

    2011-09-15

    Efficient management of the natural gas business chain - based on pipeline transmission networks and taking into consideration the interaction among the main players (e.g., shippers, suppliers, transmission companies and local distribution companies) - requires the use of decision-making support systems. These support systems maximise resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages and market demand shortfalls. This study presents a practical use for technologies, such as a thermohydraulic simulation of gas flow through pipelines, a Monte Carlo simulation for compressor station availability studies, an economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for the maximisation of income and the minimisation of contractual penalties. The proposed system allows the optimum availability level to be defined and maintained by the Transporter (by installing reserve capacity) to mitigate losses related to revenue and contractual penalties. It also economically identifies, quantifies and justifies the installation of stand-by compressor units that can mitigate the Transporter's exposure to losses caused by capacity shortfalls as a consequence of scheduled and non-scheduled outages. - Highlights: > We present a DSS to help the decision on investments on spare compressor units of pipelines systems. > The system may be applied to new or existing projects. > The system is able to estimate the revenue losses and the contractual penalties. > An economical evaluation shows the NPV for each configuration of spare units. > The method was applied to the case study of the Bolivia-Brazil gas pipeline.

  2. The development of a natural gas transportation logistics management system

    International Nuclear Information System (INIS)

    Pereira dos Santos, Sidney; Eugenio Leal, Jose; Oliveira, Fabricio

    2011-01-01

    Efficient management of the natural gas business chain - based on pipeline transmission networks and taking into consideration the interaction among the main players (e.g., shippers, suppliers, transmission companies and local distribution companies) - requires the use of decision-making support systems. These support systems maximise resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages and market demand shortfalls. This study presents a practical use for technologies, such as a thermohydraulic simulation of gas flow through pipelines, a Monte Carlo simulation for compressor station availability studies, an economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for the maximisation of income and the minimisation of contractual penalties. The proposed system allows the optimum availability level to be defined and maintained by the Transporter (by installing reserve capacity) to mitigate losses related to revenue and contractual penalties. It also economically identifies, quantifies and justifies the installation of stand-by compressor units that can mitigate the Transporter's exposure to losses caused by capacity shortfalls as a consequence of scheduled and non-scheduled outages. - Highlights: → We present a DSS to help the decision on investments on spare compressor units of pipelines systems. → The system may be applied to new or existing projects. → The system is able to estimate the revenue losses and the contractual penalties. → An economical evaluation shows the NPV for each configuration of spare units. → The method was applied to the case study of the Bolivia-Brazil gas pipeline.

  3. Logistic management system for natural gas transportation by pipelines; Sistema de gestao de logistica de transporte de gas por gasodutos

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sidney Pereira dos; Castro, Antonio Orestes de Salvo [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Leal, Jose Eugenio [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

    2008-07-01

    An efficient management of the natural gas business chain, based on pipeline transmission network and taking into consideration the interaction between the main players such as shippers, suppliers, transmission companies and local distribution companies, requires the use of decision-making support systems to maximize resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages as well as market demand shortfalls. This work presents a practical utilization of technologies such as thermohydraulic simulation of gas flow through pipelines, Monte Carlo simulation for compressor station availability studies and economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for maximization and minimization objective function. The proposed system allows the definition of the optimum availability level to be maintained by the Transporter, by means of installing redundancy, to mitigate losses related to revenue and contractual penalties. Identifies, quantifies and justifies economically the installation of stand-by compressor units, mitigating Transporter exposure to losses due to capacity shortfalls as consequence of scheduled and non-scheduled outages. (author)

  4. Gas transport in the bentonite barrier of AGP and their interfaces; Transporte de gas en la barrera de bentonita de un AGP y sus interfases

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Rodrigo, V.; Villar Gelicia, M. V.; Martin Martin, P. L.; Romero Alvarez, F. J.

    2014-07-01

    The research of gas transport processes through the barriers is of great relevance in the assessment of the behaviour of the repository. The main objective of this study is to determine the properties of gas transport in saturated bentonite samples and the interfaces between them. (Author)

  5. Reduction of gas flow into a hollow cathode ion source for a neutral beam injector

    International Nuclear Information System (INIS)

    Tanaka, S.; Akiba, M.; Arakawa, Y.; Horiike, H.; Sakuraba, J.

    1982-01-01

    Experimental studies have been made on the reduction of the gas flow rate into ion sources which utilize a hollow cathode. The electron emitter of the hollow cathode was a barium oxide impregnated porous tungsten tube. The hollow cathode was mounted to a circular or a rectangular bucket source and the following results were obtained. There was a tendency for the minimum gas flow rate for the stable source operation to decrease with increasing orifice diameter of the hollow cathode up to 10 mm. A molybdenum button with an appropriate diameter set in front of the orifice reduced the minimum gas flow rate to one half of that without button. An external magnetic field applied antiparallel to the field generated by the heater current stabilized the discharges and reduced the minimum gas flow rate to one half of that without field. Combination of the button and the antiparallel field reduced the minimum gas flow rate from the initial value (9.5 Torr 1/s) to 2.4 Torr 1/s. The reason for these effects was discussed on the basis of the theory for arc starvation

  6. Effects of neutral gas collisions on the power transmission factor at the divertor sheath

    International Nuclear Information System (INIS)

    Futch, A.H.; Matthews, G.F.; Buchenauer, D.; Hill, D.N.; Jong, R.A.; Porter, G.D.

    1992-01-01

    We show that charge-exchange and other ion-neutral collision can reduce the power transmission factor of the plasma sheath, thereby lowering the ion impact energy and target plate sputtering. The power transmission factor relates the heat flux reaching the divertor target to the plasma density and temperature just in front of the surface: δ=Q surf /J ew k T e . Experimental data from the DIII-D tokamak suggests that δ could be as low as 2-3 near the region of peak divertor particle flux, instead of the 7-8 expected from usual sheath theory. Several effects combine to allow ion-neutral interactions to be important in the divertor plasma sheath. The shallow angle of incidence of the magnetic field (1-3deg in DIII-D) leads to the spatial extension of the sheath from approximately ρ i ∝1 mm normal to the plate to several centimeters along the field lines. Ionization reduces the sheath potential, and collisions reduce the ion impact energy. (orig.)

  7. Potential of greenhouse gas emission reduction in Thai road transport by ethanol bus technology

    International Nuclear Information System (INIS)

    Chollacoop, Nuwong; Saisirirat, Peerawat; Sukkasi, Sittha; Tongroon, Manida; Fukuda, Tuenjai; Fukuda, Atsushi; Nivitchanyong, Siriluck

    2013-01-01

    Highlights: ► Energy demand modeling in Thai road transportation sector was developed. ► Such model was used to assess environment impact by ethanol bus technology (ED95). ► Ethanol bus technology (ED95) shows beneficial impacts to Thailand. ► Increase in ethanol demand and decrease in GHG emission in Thailand by ethanol bus. ► Ethanol bus (ED95) has been successfully demonstrated in Thailand. -- Abstract: Over decades, Thailand energy consumption has been concentrated in three main sectors, namely manufacturing, power and transportation. Energy consumption in transportation sector has also been dominated by road transport due to limited coverage by rail and water transportation. Hence, road transport has been a major contributor for greenhouse gas emission in Thailand over recent years. Along with global warming concern throughout the world, Thailand has taken various adaptation and mitigation measures, especially the strong policy push to use carbon–neutral biofuel in transportation sector due to Thailand competitive advantage in agriculture sector. National Renewable Energy Plan (2008–2022) has set challenging targets of 9 and 4.5 million liters/day of ethanol and biodiesel consumption by 2022, respectively. Various blends of ethanol in gasoline (10%, 20% and 85%) and biodiesel in diesel (up to 5%) have been commercially available. However, since current consumption of diesel is twice as much of gasoline, ethanol blend in gasoline would widen the imbalance consumption of gasoline and diesel. The present study however offers an insight into a possibility to use ethanol as diesel substitute. A case study of ethanol bus technology was investigated by recourse to energy demand modeling. Necessary data, such as a number of vehicles (NVs) for various vehicle types, vehicle kilometer of travel (VKT) and fuel economy (FE) were collected, with reasonable assumptions made for those unavailable data, to construct predicative energy demand model. Scenario

  8. 3D Studies of Neutral and Ionised Gas and Stars in Seyfert and Inactive Galaxies

    NARCIS (Netherlands)

    Mundell, C. G.; Dumas, G.; Schinnerer, E.; Nagar, N.; Wilcots, E.; Wilson, A. S.; Emsellem, E.; Ferruit, P.; Peletier, R. F.; De Zeeuw, P. T.; Haan, S.

    Abstract: We are conducting the first systematic 3D spectroscopic imaging survey to quantify the properties of the atomic gas (HI) in a distance-limited sample of 28 Seyfert galaxies and a sample of 28 inactive control galaxies with well-matched optical properties (the VHIKINGS survey). This study

  9. Momentum, heat, and neutral mass transport in convective atmospheric pressure plasma-liquid systems and implications for aqueous targets

    Science.gov (United States)

    Lindsay, Alexander; Anderson, Carly; Slikboer, Elmar; Shannon, Steven; Graves, David

    2015-10-01

    There is a growing interest in the study of plasma-liquid interactions with application to biomedicine, chemical disinfection, agriculture, and other fields. This work models the momentum, heat, and neutral species mass transfer between gas and aqueous phases in the context of a streamer discharge; the qualitative conclusions are generally applicable to plasma-liquid systems. The problem domain is discretized using the finite element method. The most interesting and relevant model result for application purposes is the steep gradients in reactive species at the interface. At the center of where the reactive gas stream impinges on the water surface, the aqueous concentrations of OH and ONOOH decrease by roughly 9 and 4 orders of magnitude respectively within 50 μ m of the interface. Recognizing the limited penetration of reactive plasma species into the aqueous phase is critical to discussions about the therapeutic mechanisms for direct plasma treatment of biological solutions. Other interesting results from this study include the presence of a 10 K temperature drop in the gas boundary layer adjacent to the interface that arises from convective cooling. Though the temperature magnitudes may vary among atmospheric discharge types (different amounts of plasma-gas heating), this relative difference between gas and liquid bulk temperatures is expected to be present for any system in which convection is significant. Accounting for the resulting difference between gas and liquid bulk temperatures has a significant impact on reaction kinetics; factor of two changes in terminal aqueous species concentrations like H2O2, NO2- , and NO3- are observed in this study if the effect of evaporative cooling is not included.

  10. Ecoefficiency indicators for natural gas transportation companies; Proposta de indicadores de desempenho ambiental para empresas do segmento de transporte de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    La Rovere, Emilio Lebre; Mariano, Jacqueline Barboza; Garcia, Katia Cristina; Salgado, Vivian Gullo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Planejamento Energetico; Faertes, Denise [TRANSPETRO - PETROBRAS Transporte, Rio de Janeiro, RJ (Brazil); Barata, Martha Macedo de Lima [Fundacao Inst. Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil)

    2005-07-01

    This paper aims to present a cast of environmental indicators, more specifically ecoefficiency indicators, to natural gas pipeline transportation companies. So as to do that, are defined the concepts of ecoefficiency and sustainability with its principal related environmental indicators. The environmental impacts and aspects of the natural gas pipeline transportation are discussed, and the concept of cleaner service and production is considered in the context of this activity. Are also presented and analyzed the most important indicators of environmental performance used by oil and gas companies and by natural gas transportation companies, so as to support the choice of the proposed indicators. Finally, the cast of the indicators, which was based on the assessment of the Brazilian Northeast System of gas pipelines, operated by PETROBRAS Transporte S.A., TRANSPETRO, is presented. (author)

  11. Data sets for hydrogen reflection and their use in neutral transport calculations

    International Nuclear Information System (INIS)

    Eckstein, W.; Heifetz, D.B.

    1986-08-01

    A realistic characterization of the interaction of ions and neutral particles with device walls is important for any edge plasma calculation. Present reflection models vary in detail and computational efficiency. This paper presents a data set for the distribution of the reflection coefficient, R N , over reflected energy, polar, and azimuthal angles, as functions of incident polar angle and energy. These results have been computed using a vectorized version of the TRIM Monte Carlo code. The data are stored using an algorithm for reducing the data into three one-dimensional distributions, resulting in a realistic reflection model which can be used very efficiently in plasma edge calculations. (orig.)

  12. Secure and economic operational of a gas transportation system; Operacion economica y segura de un sistema de transporte de gas

    Energy Technology Data Exchange (ETDEWEB)

    Sardi, Oscar Jose; Trichilo, Claudia; Valpreda, Carlos [Transportadora de Gas del Sur S.A. (Argentina)

    2003-07-01

    Since 1992, Transportadora de Gas del Sur (TGS) has been operating the longest gas pipeline system in South America. Prior to that date, the system was managed by GE, a state-owned company. Early on in the administration of the company, some improvement opportunities were identified in the technical, commercial, management and personnel fields. An integrated transformation process was developed which involved major investments, acquisition of new technology, re-design of the work force, and new work methodologies. The course of action followed by the company was based on an attempt to achieve permanent improvement on business results. This paper is the result of the improvements applied to our gas transportation system. Due to the time and cost assessment required by scheduled turbine compressor maintenance works (83 - 538.220 hp), a Contingency Plan for turbine compressor breakdowns was established as well as an Economic Dispatch, which can determine low-cost operations in specific periods of time (during the year). This work details the actions taken. (author)

  13. The Gaia-ESO Survey: dynamics of ionized and neutral gas in the Lagoon nebula (M 8)

    Science.gov (United States)

    Damiani, F.; Bonito, R.; Prisinzano, L.; Zwitter, T.; Bayo, A.; Kalari, V.; Jiménez-Esteban, F. M.; Costado, M. T.; Jofré, P.; Randich, S.; Flaccomio, E.; Lanzafame, A. C.; Lardo, C.; Morbidelli, L.; Zaggia, S.

    2017-08-01

    Aims: We present a spectroscopic study of the dynamics of the ionized and neutral gas throughout the Lagoon nebula (M 8), using VLT-FLAMES data from the Gaia-ESO Survey. The new data permit exploration of the physical connections between the nebular gas and the stellar population of the associated star cluster NGC 6530. Methods: We characterized through spectral fitting emission lines of Hα, [N II] and [S II] doublets, [O III], and absorption lines of sodium D doublet, using data from the FLAMES-Giraffe and UVES spectrographs, on more than 1000 sightlines toward the entire face of the Lagoon nebula. Gas temperatures are derived from line-width comparisons, densities from the [S II] doublet ratio, and ionization parameter from Hα/[N II] ratio. Although doubly-peaked emission profiles are rarely found, line asymmetries often imply multiple velocity components along the same line of sight. This is especially true for the sodium absorption, and for the [O III] lines. Results: Spatial maps for density and ionization are derived, and compared to other known properties of the nebula and of its massive stars 9 Sgr, Herschel 36 and HD 165052 which are confirmed to provide most of the ionizing flux. The detailed velocity fields across the nebula show several expanding shells, related to the cluster NGC 6530, the O stars 9 Sgr and Herschel 36, and the massive protostar M 8East-IR. The origins of kinematical expansion and ionization of the NGC 6530 shell appear to be different. We are able to put constrains on the line-of-sight (relative or absolute) distances between some of these objects and the molecular cloud. The data show that the large obscuring band running through the middle of the nebula is being compressed by both sides, which might explain its enhanced density. We also find an unexplained large-scale velocity gradient across the entire nebula. At larger distances, the transition from ionized to neutral gas is studied using the sodium lines. Based on observations

  14. A solution of the monoenergetic neutral particle transport equation for adjacent half-spaces with anisotropic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Ganapol, B.D., E-mail: ganapol@cowboy.ame.arizona.edu [Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ (United States); Mostacci, D.; Previti, A. [Montecuccolino Laboratory, University of Bologna, Via dei Colli, 16, I-40136 Bologna (Italy)

    2016-07-01

    We present highly accurate solutions to the neutral particle transport equation in a half-space. While our initial motivation was in response to a recently published solution based on Chandrasekhar's H-function, the presentation to follow has taken on a more comprehensive tone. The solution by H-functions certainly did achieved high accuracy but was limited to isotropic scattering and emission from spatially uniform and linear sources. Moreover, the overly complicated nature of the H-function approach strongly suggests that its extension to anisotropic scattering and general sources is not at all practical. For this reason, an all encompassing theory for the determination of highly precise benchmarks, including anisotropic scattering for a variety of spatial source distributions, is presented for particle transport in a half-space. We illustrate the approach via a collection of cases including tables of 7-place flux benchmarks to guide transport methods developers. The solution presented can be applied to a considerable number of one and two half-space transport problems with variable sources and represents a state-of-the-art benchmark solution.

  15. Gas Transport and Density Control in the HYLIFE Heavy-Ion Beam Lines

    International Nuclear Information System (INIS)

    Debonnel, Christophe S.; Welch, Dale R.; Rose, David V.; Lawrence, Simon S.Yu; Peterson, Per F.

    2003-01-01

    The effective propagation and focusing of heavy-ion beams in the final-focus magnet region of inertial fusion target chambers require controlling the background gas density and pressure in the beam tubes. Liquid vortexes will coat the inside of the tubes next to the beam ports and will help eliminate the need for mechanical shutters to mitigate the venting of target chamber background gas into the final-focus magnet region. Before the neutralizing region, the beam space charge is high, and ablation and target debris deposition in the final-focus magnet region may cause voltage breakdown. Previous studies focused on evaluating the amount of target chamber debris reaching the entrance of the beam ports. The TSUNAMI code has now been used to assess the density, temperature, and velocity of the vortex debris transported ∼3 m up the beam tubes and reaching the final-focus magnet region, assuming that the liquid vortexes are perfectly absorbing surfaces. To further mitigate debris deposition in the final-focus magnet region, and prevent voltage breakdown, a 'magnetic shutter' has been envisaged to divert the debris out of the final-focus region. This shutter will prevent the hot ablation debris from reaching the magnet region and, coupled to some ionizing scheme, will conveniently suppress early ingression of debris into the final-focus magnet region

  16. Beams of fast neutral atoms and molecules in low-pressure gas-discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Metel, A. S., E-mail: ametel@stankin.ru [Moscow State University of Technology ' Stankin,' (Russian Federation)

    2012-03-15

    Fast neutral atom and molecule beams have been studied, the beams being produced in a vacuum chamber at nitrogen, argon, or helium pressure of 0.1-10 Pa due to charge-exchange collisions of ions accelerated in the sheath between the glow discharge plasma and a negative grid immersed therein. From a flat grid, two broad beams of molecules with continuous distribution of their energy from zero up to e(U + U{sub c}) (where U is voltage between the grid and the vacuum chamber and U{sub c} is cathode fall of the discharge) are propagating in opposite directions. The beam propagating from the concave surface of a 0.2-m-diameter grid is focused within a 10-mm-diameter spot on the target surface. When a 0.2-m-diameter 0.2-m-high cylindrical grid covered by end disks and composed of parallel 1.5-mm-diameter knitting needles spaced by 4.5 mm is immersed in the plasma, the accelerated ions pass through the gaps between the needles, turn inside the grid into fast atoms or molecules, and escape from the grid through the gaps on its opposite side. The Doppler shift of spectral lines allows for measuring the fast atom energy, which corresponds to the potential difference between the plasma inside the chamber and the plasma produced as a result of charge-exchange collisions inside the cylindrical grid.

  17. Influence of neutral-beam injection on impurity transport in the ISX-B tokamak

    International Nuclear Information System (INIS)

    Isler, R.C.; Murray, L.E.; Kasai, S.; Arnurius, D.E.; Bates, S.C.; Crume, E.C.; Dunlap, J.L.; Edmonds, P.H.; Lazarus, E.A.; Murakami, M.; Pare, V.K.; Saltmarsh, M.J.; Swain, D.W.; Thomas, C.E.

    1981-01-01

    Observations of radiation from iron and from argon used as a test gas indicate that co-injection inhibits impurity accumulation in the interior of ISX-B discharges, but counter-injection enhances accumulation. These results agree qualitatively with recent theoretical calculations

  18. High brightness potassium ion gun for the HIF neutralized transport experiment (NTX)

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.; Roy, P.K.; Yu, S.S.

    2003-01-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. To focus a high intensity beam to a small spot requires a high brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce type diode. At the diode exit, an aperture with variable size provides the capability to vary the beam perveance and to significantly reduce the beam emittance. We shall report on the gun characterization including current density profile, phase space distributions and the control of electrons generated by the beam scraping at the aperture. Comparison with particle simulations using the EGUN code will be presented

  19. Spin effects in the screening and Auger neutralization of He+ ions in a spin-polarized electron gas

    International Nuclear Information System (INIS)

    Alducin, M.; Diez Muino, R.; Juaristi, J.I.

    2005-01-01

    The screening of a He + ion embedded in a free electron gas is studied for different spin-polarizations of the medium. Density functional theory and the local spin density approximation are used to calculate the induced electronic density for each spin orientation, i.e. parallel or antiparallel to the spin of the electron bound to the ion. Since both the He + ion and the electron gas are spin-polarized, we analyze in detail the spin state of the screening cloud for the two different possibilities: the spin of the bound electron can be parallel to either the majority spin or the minority spin in the medium. Finally, the spin-dependent Kohn-Sham orbitals are used to calculate the Auger neutralization rate of the He + ion. The polarization of the Auger excited electron is influenced by the spin-polarization of the medium. The results are discussed in terms of the spin-dependent screening and the indistinguishability of electrons with the same spin state

  20. Effects of self-similar correlations on the spectral line shape in the neutral gas

    International Nuclear Information System (INIS)

    Kharintsev, S.S.; Salakhov, M.Kh.

    2001-01-01

    The paper is devoted to the study of the influence of self-similar correlations on the Doppler and pressure broadening within the non-equilibrium Boltzmann gas. The diffuse model for the thermal motion of the radiator and the self-similar mechanism of interference of scalar perturbations for phase shifts of an atomic oscillator are developed. It is shown that taking into account self-similar correlation in a description of the spectral line shape allows one to explain, on the one hand, the additional spectral line Dicke-narrowing in the Doppler regime, and, on the other hand, the asymmetry in wings of the spectral line in a high pressure region

  1. Monoenergetic neutral particle transport in an anisotropically scattering half-space

    International Nuclear Information System (INIS)

    Ganapol, B.D.; Garth, J.C.; Woolf, S.

    1995-01-01

    During the past several years, a considerable effort has been underway to develop reliable analytical benchmark solutions to the one-speed transport equation in various geometries. The reader may well ask open-quotes whyclose quotes such a task has been undertaken, given the recent rapid advances in numerical transport theory. The simple answer is that reliable numerical solutions do not yet exist, and their development still represents a mathematical challenge. However, regardless of how mathematically challenging the development is, there are more compelling reasons for this effort which are rooted in the very fundamentals of science and technology. In particular, these solutions, which are highly accurate numerical evaluations of analytical solution representations, serve as open-quotes industry standardsclose quotes to which other more approximate methods or approximations can be compared. Thus analytical benchmarks are part of the process control and continuous improvement of numerical transport methods and are therefore integral components in TQM (Total Quality Management) as applied to transport methods development. With the above reasoning in mind, the authors begin the development and application of a new analytical solution and evaluation for a half-space featuring anisotropic scattering. This work is an extension of previous efforts in which isotropically scattering half-spaces were treated. The previous benchmarks were obtained most conveniently via a numerical Laplace transform inversion which could be applied in a straightforward manner to the case of isotropic scattering. The application of the Laplace transform method is problematical for anisotropic scattering and does not admit to the direct identification of the scalar flux from integral transport theory

  2. Insights into the Structure, Function, and Ligand Discovery of the Large Neutral Amino Acid Transporter 1, LAT1

    Directory of Open Access Journals (Sweden)

    Natesh Singh

    2018-04-01

    Full Text Available The large neutral amino acid transporter 1 (LAT1, or SLC7A5 is a sodium- and pH-independent transporter, which supplies essential amino acids (e.g., leucine, phenylalanine to cells. It plays an important role at the Blood–Brain Barrier (BBB where it facilitates the transport of thyroid hormones, pharmaceuticals (e.g., l-DOPA, gabapentin, and metabolites into the brain. Moreover, its expression is highly upregulated in various types of human cancer that are characterized by an intense demand for amino acids for growth and proliferation. Therefore, LAT1 is believed to be an important drug target for cancer treatment. With the crystallization of the arginine/agmatine antiporter (AdiC from Escherichia Coli, numerous homology models of LAT1 have been built to elucidate the substrate binding site, ligand–transporter interaction, and structure–function relationship. The use of these models in combination with molecular docking and experimental testing has identified novel chemotypes of ligands of LAT1. Here, we highlight the structure, function, transport mechanism, and homology modeling of LAT1. Additionally, results from structure–function studies performed on LAT1 are addressed, which have enhanced our knowledge of the mechanism of substrate binding and translocation. This is followed by a discussion on ligand- and structure-based approaches, with an emphasis on elucidating the molecular basis of LAT1 inhibition. Finally, we provide an exhaustive summary of different LAT1 inhibitors that have been identified so far, including the recently discovered irreversible covalent inhibitors.

  3. Analysis of particle transport in a gas target divertor

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsu, Shigeki; Tanaka, Satoru [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    2-dimensional modelling of divertor plasma was performed with three types of the divertor geometry configuration. Pumping is effective to reduce neutral recycling to core region in the configuration without baffle. In baffle configuration, a good shielding of neutrals in the divertor region can be achieved. The dome configuration reduces plasma density near the null region and flow shear near the separatrix. (author)

  4. An integrated approach to transportation policy in BC : assessing greenhouse gas reductions opportunities in freight transportation

    Energy Technology Data Exchange (ETDEWEB)

    Gouge, B.; Ries, F.; Reynolds, C.; Mazzi, E. [British Columbia Univ., Vancouver, BC (Canada). Inst. for Resources, Environment and Sustainability; Lim, C. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Civil Engineering, Bureau of Intelligent Transportation Systems and Freight Security; Dowlatabadi, H. [British Columbia Univ., Vancouver, BC (Canada). Inst. for Resources, Environment and Sustainability; British Columbia Univ., Vancouver, BC (Canada). Liu Inst. for Global Issues

    2008-11-15

    This paper presented an integrated assessment for the design of greenhouse gas (GHG) emission reduction policies in British Columbia (BC) with particular reference to the drivers of GHG emissions from the transportation sector. Transportation services are central to the movement of goods and people in modern economies and their provision involves tradeoffs between economic benefits, health effects, and social and environmental impacts. More than a dozen BC initiatives were reviewed, with a specific focus on freight movement. The paper emphasized that consequences of proposals such as low carbon fuel standards need to be carefully assessed, along with mandated vehicle technologies, congestion fees and investment in alternative transportation infrastructure. The Activity, Modal Share, Intensity and Fuel (ASIF) framework was shown to provide insight into drivers of GHG emissions and the potential impact of policy decisions. The framework refers to factors such as the amount of kilometres traveled, share of activity per mode of travel, energy intensity, and GHG emissions per unit of energy for fuel type used in the transportation mode. The relationship between factors indicates that GHG emissions increase as energy intensity increases and as the carbon intensity of fuel increases. The overall intensity of the fleet depends greatly on vehicle composition and the share of travel between different modes. refs., tabs., figs.

  5. Expert System for natural gas transportation network management; Sistema especialista para gerenciamento de redes de transporte de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jonny Carlos da; Porciuncula, Gilson Simoes [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica Lab. de Sistemas Hidraulicos e Pneumaticos

    2003-07-01

    This paper presents a project to integrate expert system and dynamic simulation of natural gas transportation network applying the concept of agents. Natural gas pipeline operation requires the intermittent analysis of hundreds interrelated operational parameters, which represent the network state. The combination of expert system and dynamic simulation is a synergic solution for this kind of problem. With expert system techniques, it is possible to implement rules that describe the relationship between current operational parameters and the network normal operational conditions based on heuristic knowledge. By applying such rules, the system aims to evaluate the real network state and to predict abnormal conditions via dynamic simulation, allowing time analysis of operational situation in advance. At the current stage, the project presents a well defined model. The process of knowledge acquisition and representation has taken place following an incremental approach, considered as development paradigm. The project objectives are to reduce costs, increase the reliability and organize pipeline operation and maintenance information. This work is part of SEGRED project established as partnership among LASHIP/UFSC, SCGAS, TBG and PETROBRAS. The project also received support from FINEP. (author)

  6. The discrete cones methods for two-dimensional neutral particle transport problems with voids

    International Nuclear Information System (INIS)

    Watanabe, Y.; Maynard, C.W.

    1983-01-01

    One of the most widely applied deterministic methods for time-independent, two-dimensional neutron transport calculations is the discrete ordinates method (DSN). The DSN solution, however, fails to be accurate in a void due to the ray effect. In order to circumvent this drawback, the authors have been developing a novel approximation: the discrete cones method (DCN), where a group of particles in a cone are simultaneously traced instead of particles in discrete directions for the DSN method. Programs, which apply to the DSN method in a non-vacuum region and the DCN method in a void, have been written for transport calculations in X-Y coordinates. The solutions for test problems demonstrate mitigation of the ray effect in voids without loosing the computational efficiency of the DSN method

  7. Kinetic neutral transport effects in the pedestal of H-mode discharges in the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Owen, L.W. [Oak Ridge National Laboratory, Building 5700, MS-6169, Oak Ridge, TN 37831-8072 (United States)]. E-mail: owenlw@ornl.gov; Groebner, R.J. [General Atomics, P.O. Box 85608, San Diego, CA 92186-9784 (United States); Mahdavi, M.A. [General Atomics, P.O. Box 85608, San Diego, CA 92186-9784 (United States)

    2005-03-01

    A series of hydrogen and deuterium discharges are analyzed with fluid plasma and Monte Carlo neutrals codes. Comparison of poloidally averaged radial distributions of core neutral density and ionization with analytic solutions of 1-D plasma and neutrals continuity equations support the hypothesis that the width of the density pedestal is largely determined by the neutral source. The increased neutral penetration depth that arises from multiple charge exchange can be included in the analytic model with radially dependent scale lengths. The scale length in the analytic model depends on the neutral fluid velocity which increases across the divertor and pedestal as the neutral atoms charge exchange with the higher temperature background ions. The neutral penetration depth and corresponding density pedestal width depend sensitively on the neutral temperature and the degree of ion-neutral temperature equilibration.

  8. Lattice Boltzmann simulations of water transport in gas diffusion layer of a polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Liang; Cheng, Ping [Ministry of Education Key Laboratory of Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiaotong University, DongChuan Road 800, Shanghai 200240 (China)

    2010-06-15

    The effect of wettability on water transport dynamics in gas diffusion layer (GDL) is investigated by simulating water invasion in an initially gas-filled GDL using the multiphase free-energy lattice Boltzmann method (LBM). The results show that wettability plays a significant role on water saturation distribution in two-phase flow in the uniform wetting GDL. For highly hydrophobicity, the water transport falls in the regime of capillary fingering, while for neutral wettability, water transport exhibits the characteristic of stable displacement, although both processes are capillary force dominated flow with same capillary numbers. In addition, the introduction of hydrophilic paths in the GDL leads the water to flow through the hydrophilic pores preferentially. The resulting water saturation distributions show that the saturation in the GDL has little change after water breaks through the GDL, and further confirm that the selective introduction of hydrophilic passages in the GDL would facilitate the removal of liquid water more effectively, thus alleviating the flooding in catalyst layer (CL) and GDL. The LBM approach presented in this study provides an effective tool to investigate water transport phenomenon in the GDL at pore-scale level with wettability distribution taken into consideration. (author)

  9. COMPLETE IONIZATION OF THE NEUTRAL GAS: WHY THERE ARE SO FEW DETECTIONS OF 21 cm HYDROGEN IN HIGH-REDSHIFT RADIO GALAXIES AND QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Curran, S. J. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Whiting, M. T., E-mail: sjc@physics.usyd.edu.au [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

    2012-11-10

    From the first published z {approx}> 3 survey of 21 cm absorption within the hosts of radio galaxies and quasars, Curran et al. found an apparent dearth of cool neutral gas at high redshift. From a detailed analysis of the photometry, each object is found to have a {lambda} = 1216 A continuum luminosity in excess of L {sub 1216} {approx} 10{sup 23} W Hz{sup -1}, a critical value above which 21 cm has never been detected at any redshift. At these wavelengths, and below, hydrogen is excited above the ground state so that it cannot absorb in 21 cm. In order to apply the equation of photoionization equilibrium, we demonstrate that this critical value also applies to the ionizing ({lambda} {<=} 912 A) radiation. We use this to show, for a variety of gas density distributions, that upon placing a quasar within a galaxy of gas, there is always an ultraviolet luminosity above which all of the large-scale atomic gas is ionized. While in this state, the hydrogen cannot be detected or engage in star formation. Applying the mean ionizing photon rate of all of the sources searched, we find, using canonical values for the gas density and recombination rate coefficient, that the observed critical luminosity gives a scale length (3 kpc) similar that of the neutral hydrogen (H I) in the Milky Way, a large spiral galaxy. Thus, this simple yet physically motivated model can explain the critical luminosity (L {sub 912} {approx} L {sub 1216} {approx} 10{sup 23} W Hz{sup -1}), above which neutral gas is not detected. This indicates that the non-detection of 21 cm absorption is not due to the sensitivity limits of current radio telescopes, but rather that the lines of sight to the quasars, and probably the bulk of the host galaxies, are devoid of neutral gas.

  10. Linking the plasma code EDGE2D to the neutral code NIMBUS for a self consistent transport model of the boundary

    International Nuclear Information System (INIS)

    De Matteis, A.

    1987-01-01

    This report describes the fully automatic linkage between the finite difference, two-dimensional code EDGE2D, based on the classical Braginskii partial differential equations of ion transport, and the Monte Carlo code NIMBUS, which solves the integral form of the stationary, linear Boltzmann equation for neutral transport in a plasma. The coupling has been performed for the real poloidal geometry of JET with two belt-limiters and real magnetic configurations with or without a single-null point. The new integrated system starts from the magnetic geometry computed by predictive or interpretative equilibrium codes and yields the plasma and neutrals characteristics in the edge

  11. Beam divergence scaling in neutral beam injectors

    International Nuclear Information System (INIS)

    Holmes, A.J.T.

    1976-01-01

    One of the main considerations in the design of neutral beam injectors is to monimize the divergence of the primary ion beam and hence maximize the beam transport and minimize the input of thermal gas. Experimental measurements of the divergence of a cylindrical ion beam are presented and these measurements are used to analyze the major components of ion beam divergence, namely: space charge expansion, gas-ion scattering, emittance and optical aberrations. The implication of these divergence components in the design of a neutral beam injector system is discussed and a method of maximizing the beam current is described for a given area of source plasma

  12. Pure- and Mixed-Gas Transport Study of Nafion® and Its Fe3+-Substituted Derivative for Membrane-Based Natural Gas Applications

    KAUST Repository

    Mukaddam, Mohsin Ahmed

    2016-01-01

    The focus of this research project was to develop a fundamental understanding of the structure-gas transport property relationship in Nafion® to investigate its potential use as a gas separation membrane material for natural gas (NG) applications

  13. TRU waste transportation -- The flammable gas generation problem

    International Nuclear Information System (INIS)

    Connolly, M.J.; Kosiewicz, S.T.

    1997-01-01

    The Nuclear Regulatory Commission (NRC) has imposed a flammable gas (i.e., hydrogen) concentration limit of 5% by volume on transuranic (TRU) waste containers to be shipped using the TRUPACT-II transporter. This concentration is the lower explosive limit (LEL) in air. This was done to minimize the potential for loss of containment during a hypothetical 60 day period. The amount of transuranic radionuclide that is permissible for shipment in TRU waste containers has been tabulated in the TRUPACT-II Safety Analysis Report for Packaging (SARP, 1) to conservatively prevent accumulation of hydrogen above this 5% limit. Based on the SARP limitations, approximately 35% of the TRU waste stored at the Idaho National Engineering and Environmental Lab (INEEL), Los Alamos National Lab (LANL), and Rocky Flats Environmental Technology Site (RFETS) cannot be shipped in the TRUPACT-II. An even larger percentage of the TRU waste drums at the Savannah River Site (SRS) cannot be shipped because of the much higher wattage loadings of TRU waste drums in that site's inventory. This paper presents an overview of an integrated, experimental program that has been initiated to increase the shippable portion of the Department of Energy (DOE) TRU waste inventory. In addition, the authors will estimate the anticipated expansion of the shippable portion of the inventory and associated cost savings. Such projection should provide the TRU waste generating sites a basis for developing their TRU waste workoff strategies within their Ten Year Plan budget horizons

  14. User's manual for ONEDANT: a code package for one-dimensional, diffusion-accelerated, neutral-particle transport

    International Nuclear Information System (INIS)

    O'Dell, R.D.; Brinkley, F.W. Jr.; Marr, D.R.

    1982-02-01

    ONEDANT is designed for the CDC-7600, but the program has been implemented and run on the IBM-370/190 and CRAY-I computers. ONEDANT solves the one-dimensional multigroup transport equation in plane, cylindrical, spherical, and two-angle plane geometries. Both regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue search) problems subject to vacuum, reflective, periodic, white, albedo, or inhomogeneous boundary flux conditions are solved. General anisotropic scattering is allowed and anisotropic inhomogeneous sources are permitted. ONEDANT numerically solves the one-dimensional, multigroup form of the neutral-particle, steady-state form of the Boltzmann transport equation. The discrete-ordinates approximation is used for treating the angular variation of the particle distribution and the diamond-difference scheme is used for phase space discretization. Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm. A standard inner (within-group) iteration, outer (energy-group-dependent source) iteration technique is used. Both inner and outer iterations are accelerated using the diffusion synthetic acceleration method

  15. Tripoli-3: monte Carlo transport code for neutral particles - version 3.5 - users manual

    International Nuclear Information System (INIS)

    Vergnaud, Th.; Nimal, J.C.; Chiron, M.

    2001-01-01

    The TRIPOLI-3 code applies the Monte Carlo method to neutron, gamma-ray and coupled neutron and gamma-ray transport calculations in three-dimensional geometries, either in steady-state conditions or having a time dependence. It can be used to study problems where there is a high flux attenuation between the source zone and the result zone (studies of shielding configurations or source driven sub-critical systems, with fission being taken into account), as well as problems where there is a low flux attenuation (neutronic calculations -- in a fuel lattice cell, for example -- where fission is taken into account, usually with the calculation on the effective multiplication factor, fine structure studies, numerical experiments to investigate methods approximations, etc). TRIPOLI-3 has been operational since 1995 and is the version of the TRIPOLI code that follows on from TRIPOLI-2; it can be used on SUN, RISC600 and HP workstations and on PC using the Linux or Windows/NT operating systems. The code uses nuclear data libraries generated using the THEMIS/NJOY system. The current libraries were derived from ENDF/B6 and JEF2. There is also a response function library based on a number of evaluations, notably the dosimetry libraries IRDF/85, IRDF/90 and also evaluations from JEF2. The treatment of particle transport is the same in version 3.5 as in version 3.4 of the TRIPOLI code; but the version 3.5 is more convenient for preparing the input data and for reading the output. The french version of the user's manual exists. (authors)

  16. Direct monitoring of wind-induced pressure-pumping on gas transport in soil

    Science.gov (United States)

    Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

    2017-04-01

    Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non

  17. The open access and the natural gas ducts: transport and distribution; O livre acesso e os dutos de gas natural: transporte e distribuicao

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, Mariana de; Xavier, Yanko Marcius de Alencar [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    The present research, attempting for the economic relevance of the natural gas sector, for the lack of a law that disciplines it and, still, for the structural question of the natural gas ducts activities; it analyzes, in a comparative way, the monopoly of the natural gas ducts activities and the mechanisms of competition chosen to brighten up it: the open access and the by pas. The transport and the distribution of the natural gas are really similar, but the ways to insert the competition in its areas are not. (author)

  18. The OpenMOC method of characteristics neutral particle transport code

    International Nuclear Information System (INIS)

    Boyd, William; Shaner, Samuel; Li, Lulu; Forget, Benoit; Smith, Kord

    2014-01-01

    Highlights: • An open source method of characteristics neutron transport code has been developed. • OpenMOC shows nearly perfect scaling on CPUs and 30× speedup on GPUs. • Nonlinear acceleration techniques demonstrate a 40× reduction in source iterations. • OpenMOC uses modern software design principles within a C++ and Python framework. • Validation with respect to the C5G7 and LRA benchmarks is presented. - Abstract: The method of characteristics (MOC) is a numerical integration technique for partial differential equations, and has seen widespread use for reactor physics lattice calculations. The exponential growth in computing power has finally brought the possibility for high-fidelity full core MOC calculations within reach. The OpenMOC code is being developed at the Massachusetts Institute of Technology to investigate algorithmic acceleration techniques and parallel algorithms for MOC. OpenMOC is a free, open source code written using modern software languages such as C/C++ and CUDA with an emphasis on extensible design principles for code developers and an easy to use Python interface for code users. The present work describes the OpenMOC code and illustrates its ability to model large problems accurately and efficiently

  19. A massively parallel method of characteristic neutral particle transport code for GPUs

    International Nuclear Information System (INIS)

    Boyd, W. R.; Smith, K.; Forget, B.

    2013-01-01

    Over the past 20 years, parallel computing has enabled computers to grow ever larger and more powerful while scientific applications have advanced in sophistication and resolution. This trend is being challenged, however, as the power consumption for conventional parallel computing architectures has risen to unsustainable levels and memory limitations have come to dominate compute performance. Heterogeneous computing platforms, such as Graphics Processing Units (GPUs), are an increasingly popular paradigm for solving these issues. This paper explores the applicability of GPUs for deterministic neutron transport. A 2D method of characteristics (MOC) code - OpenMOC - has been developed with solvers for both shared memory multi-core platforms as well as GPUs. The multi-threading and memory locality methodologies for the GPU solver are presented. Performance results for the 2D C5G7 benchmark demonstrate 25-35 x speedup for MOC on the GPU. The lessons learned from this case study will provide the basis for further exploration of MOC on GPUs as well as design decisions for hardware vendors exploring technologies for the next generation of machines for scientific computing. (authors)

  20. Effect of air turbulence on gas transport in soil; comparison of approaches

    Science.gov (United States)

    Pourbakhtiar, Alireza; Papadikis, Konstantinos; Poulsen, Tjalfe; Bridge, Jonathan; Wilkinson, Stephen

    2017-04-01

    Greenhouse gases are playing the key role in global warming. Soil is a source of greenhouse gases such as methane (CH4). Radon (Rn) which is a radioactive gas can emit form subsurface into the atmosphere and leads to health concerns in urban areas. Temperature, humidity, air pressure and vegetation of soil can affect gas emissions inside soil (Oertel et al., 2016). It's shown in many cases that wind induced fluctuations is an important factor in transport of gas through soil and other porous media. An example is: landfill gas emissions (Poulsen et al., 2001). We applied an experimental equipment for measuring controlled air turbulence on gas transport in soil in relation to the depth of sample. Two approaches for measurement of effect of wind turbulence on gas transport were applied and compared. Experiments were carried out with diffusion of CO2 and air as tracer gases with average vertical wind speeds of 0 to 0.83 m s-1. In approach A, Six different sample thicknesses from 5 to 30 cm were selected and total of 4 different wind conditions with different speed and fluctuations were applied. In approach B, a sample with constant depth was used. Five oxygen sensors were places inside sample at different depths. Total of 111 experiments were carried out. Gas transport is described by advection-dispersion equation. Gas transport is quantified as a dispersion coefficient. Oxygen breakthrough curves as a function of distance to the surface of the sample exposed to wind were derived numerically with an explicit forward time, central space finite-difference based model to evaluate gas transport. We showed that wind turbulence-induced fluctuations is an important factor in gas transport that can increase gas transport with average of 45 times more than molecular diffusion under zero wind condition. Comparison of two strategies for experiments, indicated that, constant deep samples (Approach B) are more reliable for measurement of gas transport under influence of wind

  1. Iterative convergence acceleration of neutral particle transport methods via adjacent-cell preconditioners

    International Nuclear Information System (INIS)

    Azmy, Y.Y.

    1999-01-01

    The author proposes preconditioning as a viable acceleration scheme for the inner iterations of transport calculations in slab geometry. In particular he develops Adjacent-Cell Preconditioners (AP) that have the same coupling stencil as cell-centered diffusion schemes. For lowest order methods, e.g., Diamond Difference, Step, and 0-order Nodal Integral Method (ONIM), cast in a Weighted Diamond Difference (WDD) form, he derives AP for thick (KAP) and thin (NAP) cells that for model problems are unconditionally stable and efficient. For the First-Order Nodal Integral Method (INIM) he derives a NAP that possesses similarly excellent spectral properties for model problems. The two most attractive features of the new technique are:(1) its cell-centered coupling stencil, which makes it more adequate for extension to multidimensional, higher order situations than the standard edge-centered or point-centered Diffusion Synthetic Acceleration (DSA) methods; and (2) its decreasing spectral radius with increasing cell thickness to the extent that immediate pointwise convergence, i.e., in one iteration, can be achieved for problems with sufficiently thick cells. He implemented these methods, augmented with appropriate boundary conditions and mixing formulas for material heterogeneities, in the test code APID that he uses to successfully verify the analytical spectral properties for homogeneous problems. Furthermore, he conducts numerical tests to demonstrate the robustness of the KAP and NAP in the presence of sharp mesh or material discontinuities. He shows that the AP for WDD is highly resilient to such discontinuities, but for INIM a few cases occur in which the scheme does not converge; however, when it converges, AP greatly reduces the number of iterations required to achieve convergence

  2. Assessing transition trajectories towards a sustainable energy system: A case study on the Dutch transition to climate-neutral transport fuel chains

    NARCIS (Netherlands)

    Suurs, R.A.A.; Hekkert, M.P.; Meeus, M.T.H.; Nieuwlaar, E.

    2004-01-01

    This paper proposes a method for the ex ante evaluation of technological trajectories. As a case we study the Dutch transport energy system and its transition to climate neutrality. Two technological trajectories are proposed: (i) a sequence of transition steps based on radical infrastructural

  3. Cosmic-rays, gas, and dust in nearby anticentre clouds. II. Interstellar phase transitions and the dark neutral medium

    Science.gov (United States)

    Remy, Q.; Grenier, I. A.; Marshall, D. J.; Casandjian, J. M.

    2018-03-01

    Aim. H I 21-cm and 12CO 2.6-mm line emissions trace the atomic and molecular gas phases, respectively, but they miss most of the opaque H I and diffuse H2 present in the dark neutral medium (DNM) at the transition between the H I-bright and CO-bright regions. Jointly probing H I, CO, and DNM gas, we aim to constrain the threshold of the H I-H2 transition in visual extinction, AV, and in total hydrogen column densities, NHtot. We also aim to measure gas mass fractions in the different phases and to test their relation to cloud properties. Methods: We have used dust optical depth measurements at 353 GHz, γ-ray maps at GeV energies, and H I and CO line data to trace the gas column densities and map the DNM in nearby clouds toward the Galactic anticentre and Chamaeleon regions. We have selected a subset of 15 individual clouds, from diffuse to star-forming structures, in order to study the different phases across each cloud and to probe changes from cloud to cloud. Results: The atomic fraction of the total hydrogen column density is observed to decrease in the (0.6-1) × 1021 cm-2 range in NHtot (AV ≈ 0.4 mag) because of the formation of H2 molecules. The onset of detectable CO intensities varies by only a factor of 4 from cloud to cloud, between 0.6 × 1021 cm-2 and 2.5 × 1021 cm-2 in total gas column density. We observe larger H2 column densities than linearly inferred from the CO intensities at AV > 3 mag because of the large CO optical thickness; the additional H2 mass in this regime represents on average 20% of the CO-inferred molecular mass. In the DNM envelopes, we find that the fraction of diffuse CO-dark H2 in the molecular column densities decreases with increasing AV in a cloud. For a half molecular DNM, the fraction decreases from more than 80% at 0.4 mag to less than 20% beyond 2 mag. In mass, the DNM fraction varies with the cloud properties. Clouds with low peak CO intensities exhibit large CO-dark H2 fractions in molecular mass, in particular the

  4. Multiscale model reduction for shale gas transport in fractured media

    KAUST Repository

    Akkutlu, I. Y.

    2016-05-18

    In this paper, we develop a multiscale model reduction technique that describes shale gas transport in fractured media. Due to the pore-scale heterogeneities and processes, we use upscaled models to describe the matrix. We follow our previous work (Akkutlu et al. Transp. Porous Media 107(1), 235–260, 2015), where we derived an upscaled model in the form of generalized nonlinear diffusion model to describe the effects of kerogen. To model the interaction between the matrix and the fractures, we use Generalized Multiscale Finite Element Method (Efendiev et al. J. Comput. Phys. 251, 116–135, 2013, 2015). In this approach, the matrix and the fracture interaction is modeled via local multiscale basis functions. In Efendiev et al. (2015), we developed the GMsFEM and applied for linear flows with horizontal or vertical fracture orientations aligned with a Cartesian fine grid. The approach in Efendiev et al. (2015) does not allow handling arbitrary fracture distributions. In this paper, we (1) consider arbitrary fracture distributions on an unstructured grid; (2) develop GMsFEM for nonlinear flows; and (3) develop online basis function strategies to adaptively improve the convergence. The number of multiscale basis functions in each coarse region represents the degrees of freedom needed to achieve a certain error threshold. Our approach is adaptive in a sense that the multiscale basis functions can be added in the regions of interest. Numerical results for two-dimensional problem are presented to demonstrate the efficiency of proposed approach. © 2016 Springer International Publishing Switzerland

  5. Application of an entry-exit tariff model to the gas transport system in Spain

    International Nuclear Information System (INIS)

    Alonso, Alejandro; Serrano, Miguel; Olmos, Luis

    2010-01-01

    Under an entry-exit gas tariff system, reservation of capacity is split into entry capacity, to transport gas from the injection points to a virtual balancing point, and exit capacity, to transport gas from the balancing point to the exit points in the system. Entry-exit tariff for gas transport systems have been recommended by the 3rd EU Energy Package, since they are cost reflective, facilitate gas trade and can provide signals for the location of gas injections or off-takes. The advisability of applying an entry-exit tariff system is discussed in this paper. Apart from this, authors propose an entry-exit tariff model and apply it to compute charges for the Spanish gas transport system in 2009. Results produced by the model are presented as coefficients which should multiply the current postal transport tariff. The paper concludes that entry-exit tariffs would be useful location signals which would result in a better use of the gas transport system in Spain. In those cases where demand exceeds available capacity, as it occurs at the congested connection with France, entry-exit tariffs could be supplemented by capacity charges at entry points resulting from auctions. (author)

  6. Leveling the playing field of transportation fuels: Accounting for indirect emissions of natural gas

    International Nuclear Information System (INIS)

    Sexton, Steven; Eyer, Jonathan

    2016-01-01

    Natural gas transportation fuels are credited in prior studies with greenhouse gas emissions savings relative to petroleum-based fuels and relative to the total emissions of biofuels. These analyses, however, overlook a source of potentially large indirect emissions from natural gas transportation fuels, namely the emissions from incremental coal-fired generation caused by price-induced substitutions away from natural-gas-fired electricity generation. Because coal-fired generation emits substantially more greenhouse gases and criteria air pollutants than natural-gas-fired generation, this indirect coal-use change effect diminishes potential emissions savings from natural gas transportation fuels. Estimates from a parameterized multi-market model suggest the indirect coal-use change effect rivals in magnitude the indirect land-use change effect of biofuels and renders natural gas fuels as carbon intensive as petroleum fuels. - Highlights: •Natural gas used in transport causes indirect emissions in the electricity sector. •These emissions result from increased coal use in electricity generation. •They rival in magnitude indirect land use change (ILUC) emissions of biofuels. •Natural gas fuels are estimated to be as carbon intensive as the petroleum fuels. •Policy ignores indirect emissions from natural gas.

  7. Workshop on transport for a common ion driver

    International Nuclear Information System (INIS)

    Olson, C.C.; Lee, E.; Langdon, B.

    1994-01-01

    This report contains research in the following areas related to beam transport for a common ion driver: multi-gap acceleration; neutralization with electrons; gas neutralization; self-pinched transport; HIF and LIF transport, and relevance to common ion driver; LIF and HIF reactor concepts and relevance to common ion driver; atomic physics for common ion driver; code capabilities and needed improvement

  8. Ion transport membrane module and vessel system with directed internal gas flow

    Science.gov (United States)

    Holmes, Michael Jerome; Ohrn, Theodore R.; Chen, Christopher Ming-Poh

    2010-02-09

    An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

  9. Correlating Gas Transport Parameters and X-ray Computed Tomography Measurements in Porous Media

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Hamamoto, Shoichiro; Kawamoto, Ken

    2013-01-01

    physical processes. The objective of this study was to characterize the relationships between gas transport parameters and soil-pore geometry revealed by X-ray CT. Sands of different shapes with a mean particle diameter (d50) ranging from 0.19 to 1.51 mm were used as porous media under both air...... was found between α and tortuosity calculated from gas transport parameters (Equation (Uncited) Image Tools), indicating that gas dispersivity has a linear and inverse relationship with gas diffusivity. A linear relationship was also found between ka and d50/TUMS2, indicating a strong dependency of ka...

  10. Theoretical study and design of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane and intended for cooling of gas transported in a gas-main pipeline

    KAUST Repository

    Petrenko, V.O.; Volovyk, O.S.

    2011-01-01

    This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine

  11. Adsorption and transport of charged vs. neutral hydrophobic molecules at the membrane of murine erythroleukemia (MEL) cells.

    Science.gov (United States)

    Zeng, Jia; Eckenrode, Heather M; Dai, Hai-Lung; Wilhelm, Michael J

    2015-03-01

    The adsorption and transport of hydrophobic molecules at the membrane surface of pre- and post-DMSO induced differentiated murine erythroleukemia (MEL) cells were examined by time- and wavelength-resolved second harmonic light scattering. Two medium (MEL cell, neutral BCP does not. It is suggested that an electrostatic interaction between the opposite charges of the cation and the MEL cell surface is the primary driving force for adsorption. Comparisons of adsorption density and free energy, measured at different pH and cell morphology, indicate that the interaction is predominantly through sialic acid carboxyl groups. MG cation adsorption densities have been determined as (0.6±0.3)×10(6) μm(-2) on the surface of undifferentiated MEL cells, and (1.8±0.5)×10(7) μm(-2) on differentiated MEL cells, while the deduced adsorption free energies are effectively identical (ca. -10.9±0.1 and -10.8±0.1 kcal mol(-1), respectively). The measured MG densities indicate that the total number of surface carboxyl groups is largely conserved following differentiation, and therefore the density of carboxylic groups is much larger on the differentiated cell surface than the undifferentiated one. Finally, in contrast to synthetic liposomes and bacterial membranes, surface adsorbed MG cations are unable to traverse the MEL cell membrane. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Effect of neutrals localized at torus inboard side on the impurity transport in edge stochastic magnetic field layer of LHD

    International Nuclear Information System (INIS)

    Morita, S.; Oishi, T.; Kobayashi, M.; Goto, M.; Kawamura, G.; Zhang, H.M.; Hunag, X.L.; Wang, E.H.

    2014-01-01

    Two-dimensional (2-D) distribution of impurity line emissions has been measured in Large Helical Device (LHD) based on the 2-D extreme ultraviolet (EUV) spectroscopy for studying the edge impurity transport in stochastic magnetic field layer with three-dimensional (3-D) structure. The impurity behavior in the vicinity of two X-points at inboard and outboard sides of torus becomes separately visible with the 2-D measurement. As a result, it is found that the carbon location changes from inboard to outboard X-points when the plasma axis is shifted from R_a_x=3.6 m to 3.75 m. A 3-D simulation with EMC3-EIRENE code agrees with the result at R_a_x=3.75 m but disagreed with the result at R_a_x=3.60 m. The discrepancy between the measurement and simulation at R_a_x=3.60 m is considerably reduced when the effect of neutral hydrogen localized at the inboard side is taken into account, which can modify the density gradient and friction force along the magnetic field. (author)

  13. Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

    Directory of Open Access Journals (Sweden)

    Chaohua Guo

    Full Text Available Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

  14. Feed gas contaminant removal in ion transport membrane systems

    Science.gov (United States)

    Carolan, Michael Francis [Allentown, PA; Miller, Christopher Francis [Macungie, PA

    2008-09-16

    Method for gas purification comprising (a) obtaining a feed gas stream containing one or more contaminants selected from the group consisting of volatile metal oxy-hydroxides, volatile metal oxides, and volatile silicon hydroxide; (b) contacting the feed gas stream with a reactive solid material in a guard bed and reacting at least a portion of the contaminants with the reactive solid material to form a solid reaction product in the guard bed; and (c) withdrawing from the guard bed a purified gas stream.

  15. The regulation of transportation contracts for natural gas: the issue of contractual dirigisme; A regulacao dos contratos de transporte de gas natural: a questao do dirigismo contratual

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Lizziane Souza; Siqueira, Mariana; Vasconcellos, Mariana Vannucci [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    The old principals that that rules the liberal idea of contract are replaced for a new Theory that allows the State to interfere in the private sector to please the public interest. The Gas Transport Contract has the influence of open access and its public regulation is necessary to provide the most important needs of Brazilian market. After this word about the problem, we realize the meaning of the public intervention on the Transport Contracts to protect the nation's interests and to limit the private power. This paper try to clear the meaning of the contracts regulation to the gas natural market and its influence in a Brazilian interests. (author)

  16. Water vapor and gas transport through PEO PBT block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2002-01-01

    Introduction At the bore well natural gas is saturated with water. Downstream the presence of water may cause: formation of methane hydrates (blocking eventually the pipeline), condensation of water in the pipeline and corrosion effects. A process used for the dehydration of natural gas is glycol

  17. 0-6696 : incorporating greenhouse gas (GHG) emissions in long-range transportation planning : [project summary].

    Science.gov (United States)

    2013-08-01

    Greenhouse gas (GHG) emissions continue to be : an important focus area for state, local, and : federal agencies. The transportation sector is the : second biggest contributor to GHG emissions in : the United States, and Texas contributes the : highe...

  18. Greenhouse gas emissions from aviation and marine transportation : mitigation potential and policies

    Science.gov (United States)

    2009-12-01

    This paper provides an overview of greenhouse gas (GHG) emissions : from aviation and marine transportation and the various mitigation options to reduce these emissions. Reducing global emissions by 50 to 80 percent below 1990 levels by 2050reduct...

  19. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available The need for storage of renewable energy (RE generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel

  20. Reducing Greenhouse Gas Emissions in Transport: All in One Basket?

    OpenAIRE

    Nicholas Rivers; Randall Wigle

    2018-01-01

    Analysis after analysis has shown consistently that if policy-makers aiming to meet climate goals are looking for the most-efficient, least-distortionary way to target emissions growth, there is simply nothing better than abandoning all emissions regulations except for one: A straight, revenue-neutral carbon tax. Nothing works through more channels, at a lower cost. Alas, policy-makers are not always looking for the most-efficient, least-distortionary way to target emissions growth....

  1. The analysis of the neutral gas measurements near comet P/Halley based on observations by VEGA-1

    International Nuclear Information System (INIS)

    Gringauz, K.I.; Verigin, M.I.; Remizov, A.P.; Oraevskij, A.A.; Szegoe, K.; Varga, A.

    1989-04-01

    The in-situ measurements of secondary electrons and sputtered ions caused by impacts of neutral particles on metallic surfaces of the Ram Faraday Cup and Plasma Impact Detector sensors in PLAZMAG-1 instrument aboard VEGA 1,2 spacecraft are used to estimate neutral particle density distribution (n n ) around comet P/Halley up to distances of approximately 3x10 σ km. Asymmetries in n n distributions along inbound and outbound legs of spacecraft trajectory are attributed to solar radiation pressure. A model calculation, taking into account solar radiation pressure, leads to 'tear drop' shaped distribution of neutral particles around the cometary nucleus. (author) 46 refs.; 11 figs

  2. Integrated modeling for optimized regional transportation with compressed natural gas fuel

    Directory of Open Access Journals (Sweden)

    Hossam A. Gabbar

    2016-03-01

    Full Text Available Transportation represents major energy consumption where fuel is considered as a primary energy source. Recent development in the vehicle technology revealed possible economical improvements when using natural gas as a fuel source instead of traditional gasoline. There are several fuel alternatives such as electricity, which showed potential for future long-term transportation. However, the move from current situation where gasoline vehicle is dominating shows high cost compared to compressed natural gas vehicle. This paper presents modeling and simulation methodology to optimize performance of transportation based on quantitative study of the risk-based performance of regional transportation. Emission estimation method is demonstrated and used to optimize transportation strategies based on life cycle costing. Different fuel supply scenarios are synthesized and evaluated, which showed strategic use of natural gas as a fuel supply.

  3. A model of gas generation and transport within TRU [transuranic] waste drums

    International Nuclear Information System (INIS)

    Smith, F.G. III.

    1987-01-01

    Gas generation from the radiolytic decomposition of organic material contaminated with plutonium is modeled. Concentrations of gas throughout the waste drum are determined using a diffusional transport model. The model accurately reproduces experimentally measured gas concentrations. With polyethylene waste in unvented drums, the model predicts that hydrogen gas can accumulate to concentrations greater than 4 mole percent (lower flammable limit) with about 5 Ci of plutonium. Polyethylene provides a worst case for combustible waste material. If the drum liner is punctured and a carbon composite filter vent is installed in the drum lid, the plutonium loading can be increased to 240 Ci without generating flammable gas mixtures. 5 refs., 7 figs., 4 tabs

  4. Modeling of the lithium based neutralizer for ITER neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Dure, F., E-mail: franck.dure@u-psud.fr [LPGP, Laboratoire de Physique des Gaz et Plasmas, CNRS-Universite Paris Sud, Orsay (France); Lifschitz, A.; Bretagne, J.; Maynard, G. [LPGP, Laboratoire de Physique des Gaz et Plasmas, CNRS-Universite Paris Sud, Orsay (France); Simonin, A. [IRFM, Institut de Recherche sur la Fusion Magnetique, CEA Cadarache, 13108 Saint-Paul lez Durance (France); Minea, T. [LPGP, Laboratoire de Physique des Gaz et Plasmas, CNRS-Universite Paris Sud, Orsay (France)

    2012-04-04

    Highlights: Black-Right-Pointing-Pointer We compare different lithium based neutraliser configurations to the deuterium one. Black-Right-Pointing-Pointer We study characteristics of the secondary plasma and the propagation of the 1 MeV beam. Black-Right-Pointing-Pointer Using lithium increases the neutralisation effiency keeping correct beam focusing. Black-Right-Pointing-Pointer Using lithium also reduces the backstreaming effect in direction of the ion source. - Abstract: To achieve thermonuclear temperatures necessary to produce fusion reactions in the ITER Tokamak, additional heating systems are required. One of the main method to heat the plasma ions in ITER will be the injection of energetic neutrals (NBI). In the neutral beam injector, negative ions (D{sup -}) are electrostatically accelerated to 1 MeV, and then stripped of their extra electron via collisions with a target gas, in a structure known as neutralizer. In the current ITER specification, the target gas is deuterium. It has been recently proposed to use lithium vapor instead of deuterium as target gas in the neutralizer. This would allow to reduce the gas load in the NBI vessel and to improve the neutralization efficiency. A Particle-in-Cell Monte Carlo code has been developed to study the transport of the beams and the plasma formation in the neutralizer. A comparison between Li and D{sub 2} based neutralizers made with this code is presented here, as well as a parametric study on the geometry of the Li based neutralizer. Results demonstrate the feasibility of a Li based neutralizer, and its advantages with respect to the deuterium based one.

  5. Transport evaluation of a gas-liquid scrubber

    International Nuclear Information System (INIS)

    Brodner, A.J.; Bistline, J.E.; Weber, S.E.

    1982-10-01

    The hydraulics and the mass-transfer behavior of a five-tray, single-bubble-cap, single-downcomer, gas-liquid contactor were studied for use as a gas scrubber. Flooding was not observed at the maximum available liquid and gas flow rates of 0.32 and 464 L/min, respectively. The maximum liquid entrainment was 33% at a gross liquid flow rate of 0.05 L/min. The Murphree-tray efficiencies for absorption of CO 2 (5000 ppM in air) into demineralized water ranged from 0.14 to 0.74 for volumetric liquid-to-gas ratios of 4 x 10 -4 and 2 x 10 -4 , respectively, for k/sub L/a values ranging from 0.088 to 0.36 min -1 . 12 figures, 10 tables

  6. First in situ determination of gas transport coefficients (DO2, DAr and DN2) from bulk gas concentration measurements (O2, N2, Ar) in natural sea ice

    DEFF Research Database (Denmark)

    Crabeck, O.; Delille, B.; Rysgaard, Søren

    2014-01-01

    We report bulk gas concentrations of O2, N2, and Ar, as well as their transport coefficients, in natural landfast subarctic sea ice in southwest Greenland. The observed bulk ice gas composition was 27.5% O2, 71.4% N2, and 1.09% Ar. Most previous studies suggest that convective transport is the main...... driver of gas displacement in sea ice and have neglected diffusion processes. According to our data, brines were stratified within the ice, so that no convective transport could occur within the brine system. There- fore, diffusive transport was the main driver of gas migration. By analyzing the temporal...... evolution of an internal gas peak within the ice, we deduced the bulk gas transport coefficients for oxygen (DO2), argon (DAr), and nitrogen (DN2). The values fit to the few existing estimates from experimental work, and are close to the diffusivity values in water (1025 cm2 s21). We suggest that gas...

  7. Risk from transport of gas by pipeline ''kokui-perm''

    International Nuclear Information System (INIS)

    Yelokhin, A.

    1998-01-01

    Full text of publication follows: the length of gas pipelines in Russia is 142 thousands km, 62 % are pipelines of the large diameters. Annually on gas pipelines in Russia there are more than 70 large accidents, more than 50 % from them is accompanied by ignition of gas. The average ecological looses from accident is: destruction arable lands - 78 hectares; removing from consumption agricultural soils - 6,2 hectares; destruction forests - 47,5 hectares. In work the reasons of accidents on gas pipelines of different diameters are analyzed. So, for pipelines a diameter of 1220 mm by the reasons of accidents are: marriage of civil and erection works - 39, 1 %; outside corrosion - 35,9 %; mechanical damages - 9,4 %; defects of pipes - 6,2 %; defects of the factory equipment - 1,6 %; nature disasters and other reasons - 7,8 %. In work the results of risk analysis on a gas pipeline 'Kokui - Perm' are analysed. The gas pipeline 'Kokui - Perm' passes near 22 towns and countries, crosses 15 highways, 2 rail ways, 15 rivers. In work the concrete recommendations for management of risk and safety of the population are given. (author)

  8. CNG transport by ship with FRP pressure vessels access to east coast gas

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, S. [Trans Ocean Gas Inc., St. John' s, NL (Canada)

    2005-07-01

    This paper discussed the Trans Ocean Gas (TOG) method for transporting compressed natural gas (CNG). CNG transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets that are not feasible for liquefied natural gas (LNG) or pipelines. Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. FRP pressure vessels have been proven safe and reliable through critical applications in the national defense, aerospace, and natural gas vehicle industries. They are light-weight, highly reliable, have very safe failure modes, are corrosion resistant, and have excellent low temperature characteristics. Under TOG's scheme, natural gas can be stored at two thirds the density of LNG without costly processing. TOG's proposed design and testing of a CNG system was reviewed in detail. figs.

  9. Urban form, transportation and greenhouse gas emissions- Experiences in the Nordic Countries

    Energy Technology Data Exchange (ETDEWEB)

    Harmaajaervi, I; Heinonen, S.; Lahti, P. [VTT, Building and Transport (Finland)

    2004-07-01

    The main objective of the project was to identify instruments to develop urban form and transportation systems in a sustainable way to decrease greenhouse gas emissions in the Nordic countries. Instruments can be found on different levels: national, regional and local. The main sectors are land use and transportation planning, land use and transportation policies, tax policy, co-operation, information dissemination, interaction, monitoring and early warning systems. Instruments concern for example control of urban development, supporting residential activities in city centres, control of location of shopping malls, preventing long commuting trips, reduction of transportation need and car dependency, promotion of walking, cycling and public transport and eco-managed telework. (au)

  10. Nonequilibrium Transport and the Bernoulli Effect of Electrons in a Two-Dimensional Electron Gas

    Science.gov (United States)

    Kaya, Ismet I.

    2013-02-01

    Nonequilibrium transport of charged carriers in a two-dimensional electron gas is summarized from an experimental point of view. The transport regime in which the electron-electron interactions are enhanced at high bias leads to a range of striking effects in a two-dimensional electron gas. This regime of transport is quite different than the ballistic transport in which particles propagate coherently with no intercarrier energy transfer and the diffusive transport in which the momentum of the electron system is lost with the involvement of the phonons. Quite a few hydrodynamic phenomena observed in classical gasses have the electrical analogs in the current flow. When intercarrier scattering events dominate the transport, the momentum sharing via narrow angle scattering among the hot and cold electrons lead to negative resistance and electron pumping which can be viewed as the analog of the Bernoulli-Venturi effect observed classical gasses. The recent experimental findings and the background work in the field are reviewed.

  11. Neutral beam monitoring

    International Nuclear Information System (INIS)

    Fink, J.H.

    1979-01-01

    A neutral beam generated by passing accelerated ions through a walled cell containing a low energy neutral gas, such that charge exchange partially neutralizes the high energy beam, is monitored by detecting the current flowing through the cell wall produced by low energy ions which drift to the wall after the charge exchange. By segmenting the wall into radial and longitudinal segments various beam conditions are identified. (U.K.)

  12. Engineering Development of Ceramic Membrane Reactor System for Converting Natural Gas to Hydrogen and Synthesis Gas for Liquid Transportation Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Air Products and Chemicals

    2008-09-30

    An Air Products-led team successfully developed ITM Syngas technology from the concept stage to a stage where a small-scale engineering prototype was about to be built. This technology produces syngas, a gas containing carbon monoxide and hydrogen, by reacting feed gas, primarily methane and steam, with oxygen that is supplied through an ion transport membrane. An ion transport membrane operates at high temperature and oxygen ions are transported through the dense membrane's crystal lattice when an oxygen partial pressure driving force is applied. This development effort solved many significant technical challenges and successfully scaled-up key aspects of the technology to prototype scale. Throughout the project life, the technology showed significant economic benefits over conventional technologies. While there are still on-going technical challenges to overcome, the progress made under the DOE-funded development project proved that the technology was viable and continued development post the DOE agreement would be warranted.

  13. An improved model of fission gas atom transport in irradiated uranium dioxide

    Science.gov (United States)

    Shea, J. H.

    2018-04-01

    The hitherto standard approach to predicting fission gas release has been a pure diffusion gas atom transport model based upon Fick's law. An additional mechanism has subsequently been identified from experimental data at high burnup and has been summarised in an empirical model that is considered to embody a so-called fuel matrix 'saturation' phenomenon whereby the fuel matrix has become saturated with fission gas so that the continued addition of extra fission gas atoms results in their expulsion from the fuel matrix into the fuel rod plenum. The present paper proposes a different approach by constructing an enhanced fission gas transport law consisting of two components: 1) Fick's law and 2) a so-called drift term. The new transport law can be shown to be effectively identical in its predictions to the 'saturation' approach and is more readily physically justifiable. The method introduces a generalisation of the standard diffusion equation which is dubbed the Drift Diffusion Equation. According to the magnitude of a dimensionless Péclet number, P, the new equation can vary from pure diffusion to pure drift, which latter represents a collective motion of the fission gas atoms through the fuel matrix at a translational velocity. Comparison is made between the saturation and enhanced transport approaches. Because of its dependence on P, the Drift Diffusion Equation is shown to be more effective at managing the transition from one type of limiting transport phenomenon to the other. Thus it can adapt appropriately according to the reactor operation.

  14. Estimation of Energy Consumption and Greenhouse Gas Emissions of Transportation in Beef Cattle Production

    Directory of Open Access Journals (Sweden)

    Narayanan Kannan

    2016-11-01

    Full Text Available Accounting for transportation is an important part of the life cycle analysis (LCA of beef cattle production because it is associated with energy consumption and greenhouse gas emissions. This paper describes the development and application of a model that estimates energy consumption and greenhouse gas emissions of transport in beef cattle production. The animal transport model is based on the weight and number of animals in each weight category, type of trailer, vehicle, and fuel used. The energy consumption and greenhouse gas emission estimates of animal feed transportation are based on the weight of a truckload and the number of truckloads of feed transported. Our results indicate that a truckload is travelling approximately 326 km in connection with beef cattle production in the study region. The fuel consumption amounts to 24 L of fossil fuel per 1000 kg of boneless beef. The corresponding greenhouse gas emission is 83 kg. It appears from our results that the majority of energy consumption and greenhouse gas emissions are associated with sending the finished cattle to slaughterhouses and bringing feeder cattle to feedlots. Our results point out appreciable reductions in energy consumption and greenhouse gas emissions by changing from conventional fuel to bio-fuel.

  15. Transport and reaction processes affecting the attenuation of landfill gas in cover soils

    DEFF Research Database (Denmark)

    Molins, S.; Mayer, K.U.; Scheutz, Charlotte

    2008-01-01

    of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate, the contributions of various gas transport processes on methane attenuation in landfill cover soils....... For this purpose, a reactive transport model that includes advection and the Dusty Gas Model for simulation of multicomponent gas diffusion was used. The simulations are constrained by data from a series of counter-gradient laboratory experiments. Diffusion typically accounts for over 99% of methane emission...... to the atmosphere. Oxygen supply into the soil column is driven exclusively by diffusion, whereas advection outward offsets part of the diffusive contribution. In the reaction zone, methane consumption reduces the pressure gradient, further decreasing the significance of advection near the top of the column...

  16. Thinking on Sichuan-Chongqing gas pipeline transportation system reform under market-oriented conditions

    Science.gov (United States)

    Duan, Yanzhi

    2017-01-01

    The gas pipeline networks in Sichuan and Chongqing (Sichuan-Chongqing) region have formed a fully-fledged gas pipeline transportation system in China, which supports and promotes the rapid development of gas market in Sichuan-Chongqing region. In the circumstances of further developed market-oriented economy, it is necessary to carry out further the pipeline system reform in the areas of investment/financing system, operation system and pricing system to lay a solid foundation for improving future gas production and marketing capability and adapting itself to the national gas system reform, and to achieve the objectives of multiparty participated pipeline construction, improved pipeline transportation efficiency and fair and rational pipeline transportation prices. In this article, main thinking on reform in the three areas and major deployment are addressed, and corresponding measures on developing shared pipeline economy, providing financial support to pipeline construction, setting up independent regulatory agency to enhance the industrial supervision for gas pipeline transportation, and promoting the construction of regional gas trade market are recommended.

  17. Quantities of natural gas transmitted in January-December 2012. Quantities of natural gas transported in January-December 2012

    International Nuclear Information System (INIS)

    2013-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2012: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  18. Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

    2015-09-01

    This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

  19. Price dynamics in the market for Liquid Petroleum Gas transport

    International Nuclear Information System (INIS)

    Adland, Roar; Jia Haiying; Lu Jing

    2008-01-01

    The purpose of this paper is to investigate the dynamics of the spot freight rate in the Liquid Petroleum Gas (LPG) shipping market. The spot freight rate process is nonparametrically specified so that the model allows for maximal flexibility in fitting the data. The model is estimated using data for the Very Large Gas Carrier (VLGC) sector and the estimation results are compared to those of crude oil tankers available in the literature. The empirical results suggest that the LPG spot freight rate can be appropriately described by a simple linear stochastic model and does not exhibit the non-linearity found in other bulk shipping sectors

  20. Perturbative studies of toroidal momentum transport using neutral beam injection modulation in the Joint European Torus: Experimental results, analysis methodology, and first principles modeling

    DEFF Research Database (Denmark)

    Mantica, P.; Tala, T.; Ferreira, J.S.

    2010-01-01

    Perturbative experiments have been carried out in the Joint European Torus [Fusion Sci. Technol. 53(4) (2008)] in order to identify the diffusive and convective components of toroidal momentum transport. The torque source was modulated either by modulating tangential neutral beam power...... or by modulating in antiphase tangential and normal beams to produce a torque perturbation in the absence of a power perturbation. The resulting periodic perturbation in the toroidal rotation velocity was modeled using time-dependent transport simulations in order to extract empirical profiles of momentum...

  1. Fundamentals of gas counters

    International Nuclear Information System (INIS)

    Bateman, J.E.

    1994-01-01

    The operation of gas counters used for detecting radiation is explained in terms of the four fundamental physical processes which govern their operation. These are 1) conversion of neutral radiation into charged particles, 2) ionization of the host gas by a fast charge particle 3) transport of the gas ions to the electrodes and 4) amplification of the electrons in a region of enhanced electric field. Practical implications of these are illustrated. (UK)

  2. Marine transportation of liquefied natural gas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Curt, R.P.; Delaney, T.D.

    1973-01-01

    This report covers in some detail most of the major areas of consideration involved in the marine carriage of LNG. Some of the fields investigated and reviewed are the world's total energy picture and the particular requirements of natural gas in the United States in the near future. (GRA)

  3. Monitoring of energy efficiency of technological modes of gas transport using modern gas-turbine equipment

    Science.gov (United States)

    Golik, V. V.; Zemenkova, M. Yu; Shipovalov, A. N.; Akulov, K. A.

    2018-05-01

    The paper presents calculations and an example of energy efficiency justification of the regimes of the equipment used. The engineering design of the gas pipeline in the part of monitoring the energy efficiency of a gas compressor unit (GCU) is considered. The results of the GCU characteristics and its components evaluation are described. The evaluation results of the energy efficiency indicators of the gas pipeline are presented. As an example of the result of the analysis, it is proposed to use gas compressor unit GCU-32 "Ladoga" because of its efficiency and cost effectiveness, in comparison with analogues.

  4. Analysis of volatile phase transport in soils using natural radon gas as a tracer

    International Nuclear Information System (INIS)

    Chen, C.; Thomas, D.M.

    1992-01-01

    We have conducted a field study of soil gas transport processes using radon gas as a naturally occurring tracer. The experiment monitored soil gas radon activity, soil moisture, and soil temperature at three depths in the shallow soil column; barometric pressure, rainfall and wind speed were monitored at the soil surface. Linear and multiple regression analysis of the data sets has shown that the gas phase radon activities under natural environmental conditions are influenced by soil moisture content, barometric pressure variations, soil temperature and soil structure. The effect of wind speed on subsurface radon activities under our field conditions has not been demonstrated

  5. Report of the experts group on the taxation of the access to gas transport and distribution network

    International Nuclear Information System (INIS)

    2001-04-01

    In the framework of a new french gas industry organization (directive of the 22 june 1998), a concerting mission has been realized on prices taxation for the transport and distribution facilities. The following topics have been debated: the integration and competition of the european gas market, the gas market liberalization consistency and the taxation of transport and distribution network access. (A.L.B.)

  6. METHANOL PRODUCTION FROM BIOMASS AND NATURAL GAS AS TRANSPORTATION FUEL

    Science.gov (United States)

    Two processes are examined for production of methanol. They are assessed against the essential requirements of a future alternative fuel for road transport: that it (i) is producible in amounts comparable to the 19 EJ of motor fuel annually consumed in the U.S., (ii) minimizes em...

  7. Membranes for Flue Gas Treatment - Transport behavior of water and gas in hydrophilic polymer membranes

    NARCIS (Netherlands)

    Potreck, Jens

    2009-01-01

    Fossil fuel fired power plants produce electricity and in addition to that large volume flows of flue gas, which mainly contain N2, O2, and CO2, but also large quantities of water vapor. To prevent condensation of the water vapor present in this flue gas stream, water needs to be removed before

  8. Transport Insight 2009. An annual behind-the-scenes view in North West European gas transmission

    International Nuclear Information System (INIS)

    2009-09-01

    Transport Insight provides the users of the gas network, customers (shippers) and other stakeholders with clear and coherent information every year, directly from the source; the Transmission System Operators. TSOs Gas Transport Services (GTS) and Gasunie Deutschland (GUD) have worked closely together to present Transport Insight 2009 as a joint publication. Section 1 describes the major developments and circumstances that affected the gas transmission system in 2008. Section 2 gives in-depth analyses of actual gas transmission at the border clusters of the Gas Transport Services and Gasunie Deutschland grids. These are illustrated in graphs by means of key figures from 2008 and show details of availability, contracted capacity and usage. Section 3 considers trends in Europe, specifically looking at the production decline and swing decline. These sections are followed by the themes in section 4. In these themes a specific topic is discussed in more detail. The first theme describes developments concerning the Title Transfer Facility (TTF) and the Virtual Trading Place (VHP). The second theme focuses on trends in gas storage in Europe.

  9. Transport Insight 2009. An annual behind-the-scenes view in North West European gas transmission

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-09-15

    Transport Insight provides the users of the gas network, customers (shippers) and other stakeholders with clear and coherent information every year, directly from the source; the Transmission System Operators. TSOs Gas Transport Services (GTS) and Gasunie Deutschland (GUD) have worked closely together to present Transport Insight 2009 as a joint publication. Section 1 describes the major developments and circumstances that affected the gas transmission system in 2008. Section 2 gives in-depth analyses of actual gas transmission at the border clusters of the Gas Transport Services and Gasunie Deutschland grids. These are illustrated in graphs by means of key figures from 2008 and show details of availability, contracted capacity and usage. Section 3 considers trends in Europe, specifically looking at the production decline and swing decline. These sections are followed by the themes in section 4. In these themes a specific topic is discussed in more detail. The first theme describes developments concerning the Title Transfer Facility (TTF) and the Virtual Trading Place (VHP). The second theme focuses on trends in gas storage in Europe.

  10. How gas-guzzler conversions can accelerate transportation electrification

    Energy Technology Data Exchange (ETDEWEB)

    Gremban, R. [California Cars Initiative, Palo Alto, CA (United States)

    2010-07-01

    This presentation discussed how plug-in hybrid electric vehicles (PHEV) can ramp up to accelerate greenhouse gas reductions. Specific topics that were presented included required battery manufacturing capacity; rapid conversion of light, medium, and heavy-duty ICE vehicles in the United States into battery electric vehicles and PHEVs; the low hanging fruits such as pickups, vans, larger vehicles, and those with defined drive cycles; the economics of gas guzzler conversions; and Canada and Japan policies on conversions. United States' measures supporting electric vehicle/(PHEV) conversions was also addressed. Some examples of converting vehicles to PHEVs were also outlined. The presentation concluded with some key themes to begin now for market penetration. It was concluded that without ICE conversions, market penetration was too slow. figs.

  11. Description of the Gas Transport through Dynamic Liquid Membrane.

    Czech Academy of Sciences Publication Activity Database

    Uchytil, Petr; Setničková, Kateřina; Tseng, H.-H.; Šíma, Vladimír; Petričkovič, Roman

    2017-01-01

    Roč. 184, AUG 31 (2017), s. 152-157 ISSN 1383-5866 Grant - others:AV ČR(CZ) MOST-16-04 Program:Bilaterální spolupráce Institutional support: RVO:67985858 Keywords : gas separation * liquid membrane * solurion-diffusion model Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 3.359, year: 2016

  12. The Star Formation Rate Efficiency of Neutral Atomic-Dominated Hydrogen Gas in the Ooutskirts of Star-Forming Galaxies From z approx. 1 to z approx. 3

    Science.gov (United States)

    Rafelski, Marc; Gardner, Jonathan P.; Fumagalli, Michele; Neeleman, Marcel; Teplitz, Harry I.; Grogin, Norman; Koekemoer, Anton M.; Scarlata, Claudia

    2016-01-01

    Current observational evidence suggests that the star formation rate (SFR)efficiency of neutral atomic hydrogen gas measured in damped Ly(alpha) systems (DLAs) at z approx. 3 is more than 10 times lower than predicted by the Kennicutt-Schmidt (KS)relation. To understand the origin of this deficit, and to investigate possible evolution with redshift and galaxy properties, we measure the SFR efficiency of atomic gas at z approx. 1, z approx. 2, and z approx. 3 around star-forming galaxies. We use new robust photometric redshifts in the Hubble Ultra Deep Field to create galaxy stacks in these three redshift bins, and measure the SFR efficiency by combining DLA absorber statistics with the observed rest-frame UV emission in the galaxies' outskirts. We find that the SFR efficiency of H I gas at z > 1 is approx. 1%-3% of that predicted by the KS relation. Contrary to simulations and models that predict a reduced SFR efficiency with decreasing metallicity and thus with increasing redshift, we find no significant evolution in the SFR efficiency with redshift. Our analysis instead suggests that the reduced SFR efficiency is driven by the low molecular content of this atomic-dominated phase, with metallicity playing a secondary effect in regulating the conversion between atomic and molecular gas. This interpretation is supported by the similarity between the observed SFR efficiency and that observed in local atomic-dominated gas, such as in the outskirts of local spiral galaxies and local dwarf galaxies.

  13. Transportation and Greenhouse Gas Emissions Trading. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Steve Winkelman; Tim Hargrave; Christine Vanderlan

    1999-10-01

    The authors conclude in this report that an upstream system would ensure complete regulatory coverage of transportation sector emissions in an efficient and feasible manner, and as such represents a key component of a national least-cost GHG emissions abatement strategy. The broad coverage provided by an upstream system recommends this approach over vehicle-maker based approaches, which would not cover emissions from heavy-duty vehicles and the aviation, marine and off-road sub-sectors. The on-road fleet approach unfairly and inefficiently burdens vehicle manufacturers with responsibility for emissions that they cannot control. A new vehicles approach would exclude emissions from vehicles on the road prior to program inception. The hybrid approach faces significant technical and political complications, and it is not clear that the approach would actually change behavior among vehicle makers and users, which is its main purpose. They also note that a trading system would fail to encourage many land use and infrastructure measures that affect VMT growth and GHG emissions. They recommend that this market failure be addressed by complementing the trading system with a program specifically targeting land use- and infrastructure-related activities. A key issue that must be addressed in designing a national GHG control strategy is whether or not it is necessary to guarantee GHG reductions from the transport sector. Neither an upstream system nor a downstream approach would do so, since both would direct capital to the least-cost abatement opportunities wherever they were found. They review two reasons why it may be desirable to force transportation sector reductions: first, that the long-term response to climate change will require reductions in all sectors; and second, the many ancillary benefits associated with transportation-related, and especially VMT-related, emissions reduction activities. If policy makers find it desirable to establish transportation

  14. Numerical solution of fractured horizontal wells in shale gas reservoirs considering multiple transport mechanisms

    Science.gov (United States)

    Zhao, Yu-long; Tang, Xu-chuan; Zhang, Lie-hui; Tang, Hong-ming; Tao, Zheng-Wu

    2018-06-01

    The multiscale pore size and specific gas storage mechanism in organic-rich shale gas reservoirs make gas transport in such reservoirs complicated. Therefore, a model that fully incorporates all transport mechanisms and employs an accurate numerical method is urgently needed to simulate the gas production process. In this paper, a unified model of apparent permeability was first developed, which took into account multiple influential factors including slip flow, Knudsen diffusion (KD), surface diffusion, effects of the adsorbed layer, permeability stress sensitivity, and ad-/desorption phenomena. Subsequently, a comprehensive mathematical model, which included the model of apparent permeability, was derived to describe gas production behaviors. Thereafter, on the basis of unstructured perpendicular bisection grids and finite volume method, a fully implicit numerical simulator was developed using Matlab software. The validation and application of the new model were confirmed using a field case reported in the literature. Finally, the impacts of related influencing factors on gas production were analyzed. The results showed that KD resulted in a negligible impact on gas production in the proposed model. The smaller the pore size was, the more obvious the effects of the adsorbed layer on the well production rate would be. Permeability stress sensitivity had a slight effect on well cumulative production in shale gas reservoirs. Adsorbed gas made a major contribution to the later flow period of the well; the greater the adsorbed gas content, the greater the well production rate would be. This paper can improve the understanding of gas production in shale gas reservoirs for petroleum engineers.

  15. Transportation Energy Futures Series: Effects of the Built Environment on Transportation: Energy Use, Greenhouse Gas Emissions, and Other Factors

    Energy Technology Data Exchange (ETDEWEB)

    Porter, C. D.; Brown, A.; Dunphy, R. T.; Vimmerstedt, L.

    2013-03-01

    Planning initiatives in many regions and communities aim to reduce transportation energy use, decrease emissions, and achieve related environmental benefits by changing land use. This report reviews and summarizes findings from existing literature on the relationship between the built environment and transportation energy use and greenhouse gas emissions, identifying results trends as well as potential future actions. The indirect influence of federal transportation and housing policies, as well as the direct impact of municipal regulation on land use are examined for their effect on transportation patterns and energy use. Special attention is given to the 'four D' factors of density, diversity, design and accessibility. The report concludes that policy-driven changes to the built environment could reduce transportation energy and GHG emissions from less than 1% to as much as 10% by 2050, the equivalent of 16%-18% of present-day urban light-duty-vehicle travel. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  16. Transportation Energy Futures Series. Effects of the Built Environment on Transportation. Energy Use, Greenhouse Gas Emissions, and Other Factors

    Energy Technology Data Exchange (ETDEWEB)

    Porter, C. D. [National Renewable Energy Lab. (NREL) and Cambridge Systematics, Inc., Golden, CO (United States); Brown, A. [National Renewable Energy Lab. (NREL) and Cambridge Systematics, Inc., Golden, CO (United States); Dunphy, R. T. [National Renewable Energy Lab. (NREL) and Cambridge Systematics, Inc., Golden, CO (United States); Vimmerstedt, L. [National Renewable Energy Lab. (NREL) and Cambridge Systematics, Inc., Golden, CO (United States)

    2013-03-15

    Planning initiatives in many regions and communities aim to reduce transportation energy use, decrease emissions, and achieve related environmental benefits by changing land use. This report reviews and summarizes findings from existing literature on the relationship between the built environment and transportation energy use and greenhouse gas emissions, identifying results trends as well as potential future actions. The indirect influence of federal transportation and housing policies, as well as the direct impact of municipal regulation on land use are examined for their effect on transportation patterns and energy use. Special attention is given to the 'four D' factors of density, diversity, design and accessibility. The report concludes that policy-driven changes to the built environment could reduce transportation energy and GHG emissions from less than 1% to as much as 10% by 2050, the equivalent of 16%-18% of present-day urban light-duty-vehicle travel. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  17. Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

    Energy Technology Data Exchange (ETDEWEB)

    Gordillo-Vazquez, F J [Instituto de Astrofisica de Andalucia (IAA), CSIC, PO Box 3004, 18080 Granada (Spain); Donko, Z [Research Institute for Solid State Physics and Optics, H-1525 Budapest, PO Box, 49 (Hungary)

    2009-08-15

    A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, {approx}215 K (at 11 km) and {approx}198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N {<=} 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas

  18. Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

    International Nuclear Information System (INIS)

    Gordillo-Vazquez, F J; Donko, Z

    2009-01-01

    A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, ∼215 K (at 11 km) and ∼198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N ≤ 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas temperature is only slightly

  19. Distribution of E/N and N/e/ in a cross-flow electric discharge laser. [electric field to neutral gas density and electron number density

    Science.gov (United States)

    Dunning, J. W., Jr.; Lancashire, R. B.; Manista, E. J.

    1976-01-01

    Measurements have been conducted of the effect of the convection of ions and electrons on the discharge characteristics in a large scale laser. The results are presented for one particular distribution of ballast resistance. Values of electric field, current density, input power density, ratio of electric field to neutral gas density (E/N), and electron number density were calculated on the basis of measurements of the discharge properties. In a number of graphs, the E/N ratio, current density, power density, and electron density are plotted as a function of row number (downstream position) with total discharge current and gas velocity as parameters. From the dependence of the current distribution on the total current, it appears that the electron production in the first two rows significantly affects the current flowing in the succeeding rows.

  20. Improved treatment of two-dimensional neutral particle transport through voids within the discrete ordinates method by use of generalized view factors

    International Nuclear Information System (INIS)

    Brockmann, H.

    1992-01-01

    Using the discrete ordinates method for the treatment of neutral particle transport through voids serious flux distortions may occur due to the restricted streaming of particles along discrete directions. For mitigating this type of ray effect the method of view factors is proposed which has been developed in the theory of thermal radiation for describing the radiant exchange among surfaces. In order to apply this method to transport theory generalized view factors are defined which regard the angular dependence of the radiation leaving the surfaces. The generalized view factors are calculated analytically for r-z cylinder geometries and by applying the view factor algebra. The method was realized in the discrete ordinates transport code DOT 4.2 and applied to an r-z analogue of the S I S (Square-In-Square) sample problem. The results of the proposed method are compared with those calculated by the common discrete ordinates method and the Monte Carlo method

  1. The features of oil & gas complex's strategic management and hydrocarbon products transportation at developing marine oil & gas fields in Arctic

    Directory of Open Access Journals (Sweden)

    Fadeev А. М.

    2017-12-01

    Full Text Available The paper considers some theoretical and practical issues of strategic management of oil and gas complex at the development of hydrocarbon resources in the Arctic offshore. The analysis of existing approaches in process and project management of oil and gas complex has been carried out taking into account characteristics of offshore projects in the Arctic zone. Considerable attention has been paid to the history and evolution of strategic management as an economic category, functional areas of strategic management at different levels of management have been proposed. The analysis of existing scientific works dedicated to the projects on the Arctic shelf, has shown insufficient development of the strategic management's theory and practice. In particular, the biggest part of the scientific studies is focused on studying issues of the management at the corporate level, at the same time questions at the level of the oil and gas complex are not considered. In existing studies, the project and process approaches to management are often opposed to each other, and according to the authors it is incorrect in relation to the management of the oil and gas complex on the Arctic shelf. The oil and gas complex is a complex and multilevel system that implements unprecedentedly difficult projects in terms of technology. The beginning of hydrocarbon production on the Arctic shelf is inextricably linked with the transportation of extracted raw materials to the processing and marketing sites; it complements the strategic management of the oil and gas complex by the features of organizing efficient transport and logistics solutions.

  2. Pure- and Mixed-Gas Transport Study of Nafion® and Its Fe3+-Substituted Derivative for Membrane-Based Natural Gas Applications

    KAUST Repository

    Mukaddam, Mohsin A.

    2016-05-26

    The focus of this research project was to develop a fundamental understanding of the structure-gas transport property relationship in Nafion® to investigate its potential use as a gas separation membrane material for natural gas (NG) applications including carbon dioxide removal from NG, helium recovery, higher-hydrocarbon removal, and nitrogen separation from methane. Separation processes account for ~45% of all energy used in chemical plants and petroleum refineries. As the drive for energy savings and sustainability intensifies, more efficient separation technology becomes increasingly important. Saudi Arabia ranks among the world’s top 5 NG producers. Commercial hydrocarbon-based glassy polymers often lose their gas separation properties in the presence of condensable, highly sorbing NG components such as CO2, ethane, propane, n-butane, and C5+ hydrocarbons. This deterioration in gas separation performance results from penetrant-induced dilation and plasticization of the polymer matrix, leading to significant methane and higher hydrocarbon losses. Polymers that have intrinsically low affinity to high-solubility NG components may be less susceptible to plasticization and therefore offer better performance under actual field conditions. By virtue of their strong carbon-fluorine bonds and chemical inertness, perfluoropolymers exhibit very low affinity for hydrocarbon gases. Nafion®, the prototypical perfluoro-sulfonated ionomer, comprising hydrophilic sulfonate groups phase-separated from a hydrophobic perfluorocarbon matrix, has demonstrated interesting permeability and selectivity relationships for gas pairs relevant to NG applications. Gas transport properties of Nafion® indicated gas solubility behavior similar to rubbery polymers but with sieving properties more commonly observed in low free volume glassy polymers. Nafion® demonstrated very low solubility for CO2 and hydrocarbon gases; the trend-line slope of solubility versus penetrant condensability

  3. Specialists' meeting on fission product release and transport in gas-cooled reactors. Summary report

    International Nuclear Information System (INIS)

    1985-01-01

    The purpose of the Meeting on Fission Product Release and Transport in Gas-Cooled Reactors was to compare and discuss experimental and theoretical results of fission product behaviour in gas-cooled reactors under normal and accidental conditions and to give direction for future development. The technical part of the meeting covered operational experience and laboratory research, activity release, and behaviour of released activity

  4. Specialists' meeting on fission product release and transport in gas-cooled reactors. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1985-07-01

    The purpose of the Meeting on Fission Product Release and Transport in Gas-Cooled Reactors was to compare and discuss experimental and theoretical results of fission product behaviour in gas-cooled reactors under normal and accidental conditions and to give direction for future development. The technical part of the meeting covered operational experience and laboratory research, activity release, and behaviour of released activity.

  5. Opportunities for Synergy Between Natural Gas and Renewable Energy in the Electric Power and Transportation Sectors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.; Zinaman, O.; Logan, J.

    2012-12-01

    Use of both natural gas and renewable energy has grown significantly in recent years. Both forms of energy have been touted as key elements of a transition to a cleaner and more secure energy future, but much of the current discourse considers each in isolation or concentrates on the competitive impacts of one on the other. This paper attempts, instead, to explore potential synergies of natural gas and renewable energy in the U.S. electric power and transportation sectors.

  6. Ion transport membrane reactor systems and methods for producing synthesis gas

    Science.gov (United States)

    Repasky, John Michael

    2015-05-12

    Embodiments of the present invention provide cost-effective systems and methods for producing a synthesis gas product using a steam reformer system and an ion transport membrane (ITM) reactor having multiple stages, without requiring inter-stage reactant injections. Embodiments of the present invention also provide techniques for compensating for membrane performance degradation and other changes in system operating conditions that negatively affect synthesis gas production.

  7. Gas Transport through Fractured Rock near the U20az Borehole, Pahute Mesa, Nevada.

    Science.gov (United States)

    Rockhold, M.; Lowrey, J. D.; Kirkham, R.; Olsen, K.; Waichler, S.; White, M. D.; Wurstner White, S.

    2017-12-01

    Field experiments were performed in 2012-13 and 2016-17 at the U-20az testbed at the Nevada National Security Site to develop and evaluate capabilities for monitoring and modeling noble gas transport associated with underground nuclear explosions (UNE). Experiments were performed by injecting both chemical (CF2BR2, SF6) and radioactive (37Ar, 127Xe) gas species into the deep subsurface at this legacy UNE site and monitoring the breakthrough of the gases at different locations on or near the ground surface. Gas pressures were also monitored in both the chimney and at ground surface. Field experiments were modeled using the parallel, non-isothermal, two-phase flow and transport simulator, STOMP-GT. A site conceptual-numerical model was developed from a geologic framework model, and using a dual-porosity/permeability model for the constitutive relative permeability-saturation-capillary pressure relations of the fractured rock units. Comparisons of observed and simulated gas species concentrations show that diffusion is a highly effective transport mechanism under ambient conditions in the water-unsaturated fractured rock. Over-pressurization of the cavity during one of the field campaigns, and barometric pressure fluctuations are shown to result in enhanced gas transport by advection through fractures.

  8. The tariffs of use of liquefied natural gas transportation networks and facilities

    International Nuclear Information System (INIS)

    2005-01-01

    The new tariff proposals for the use of natural gas transportation networks were transmitted to the French Ministry of economy, finances and industry on October 27, 2004 by the commission of energy regulation. These proposals have been adopted and are the object of three legislative texts: the decree no. 2005-607 from May 27 2005 relative to the tariffing rules, the by-law from May 27, 2005 relative to the definition of balancing areas, and the advice from May 27, 2005 relative to the tariffs of use of natural gas transportation networks. In application of article 7 of the law from January 3, 2003, the implementation of the first tariffs of use of natural gas transportation networks and of liquefied natural gas (LNG) facilities is defined in the decree no. 2004-994 from September 21, 2004. On the main transportation network, the tariffing is of 'input-output' type and does not depend on the distance, while at the regional network scale, the tariffing is linked with the distance. The tariff of use of LNG facilities is the sum of 4 terms: a fixed term applied to each batch unloaded at the methane terminal, a term proportional to the unloaded LNG quantities, a term depending on the duration of use of LNG storage facilities and a term covering the gas consumptions of LNG facilities. This document gathers these different legislative texts with their appendixes. (J.S.)

  9. Greenhouse gas emissions from the production and use of alternative transport fuels

    International Nuclear Information System (INIS)

    Le Cornu, J.K.

    1990-01-01

    A number of the commonly proposed alternative transport fuels were ranked according to both the cumulative greenhouse gas emissions and the production costs incurred between the recovery of the prime resource and the fuel's end use by the Australian transport fleet. An examination of the emissions of each greenhouse gas at each production stage confirmed the common presumption that the low levels of secondary greenhouse gas emissions involved contribute little to the overall greenhouse impact of a fuel's production and use. From a greenhouse point of view the transport fuels studied could be reasonable well ranked by considering their carbon dioxide emissions alone. A possible exception may apply in the case of the compressed natural gas option, which may need to separate consideration of the effect of fugitive emissions of methane from gas distribution systems. An assumption involved in reaching this result was that nitrous oxide emissions, on which there was inadequate hard data, would not form more than 1% of the total nitrogen oxide emissions. At such an emission level it could contribute up to 5% of a fuel's total greenhouse impact. It is concluded that apart from some small niche opportunities, there is no Australian alternative transport fuel option whose production cost and greenhouse impact makes it one which policy should favour over other fuels. It is stressed that this is no more than a preliminary scouting study of generic options, which addresses only greenhouse issues. 17 refs., 1 tab., 8 figs

  10. Applications of ZigBee Technology in the Safety Monitoring System of Low Gas Pipeline Transportation

    Directory of Open Access Journals (Sweden)

    Wei Deyu

    2015-01-01

    Full Text Available The existing safety monitoring system of low gas pipeline transportation establishes a wired communication network monitoring system mainly on the basis of industrial bus. It has problems such as large transmission signal attenuation, complex wiring, high-labor intensity, inconvenient installation and maintenance, high maintenance cost, and so on. Featuring low cost, power-saving, reliability, stability and flexibility, the wireless sensor network established by ZigBee wireless communication technology can realize the real-time all-dimensional dynamic monitoring on parameters of low gas pipeline transportation system and overcome the shortcomings and deficiencies of wired network system.

  11. Multimodel analysis of anisotropic diffusive tracer-gas transport in a deep arid unsaturated zone

    Science.gov (United States)

    Green, Christopher T.; Walvoord, Michelle Ann; Andraski, Brian J.; Striegl, Robert G.; Stonestrom, David A.

    2015-01-01

    Gas transport in the unsaturated zone affects contaminant flux and remediation, interpretation of groundwater travel times from atmospheric tracers, and mass budgets of environmentally important gases. Although unsaturated zone transport of gases is commonly treated as dominated by diffusion, the characteristics of transport in deep layered sediments remain uncertain. In this study, we use a multimodel approach to analyze results of a gas-tracer (SF6) test to clarify characteristics of gas transport in deep unsaturated alluvium. Thirty-five separate models with distinct diffusivity structures were calibrated to the tracer-test data and were compared on the basis of Akaike Information Criteria estimates of posterior model probability. Models included analytical and numerical solutions. Analytical models provided estimates of bulk-scale apparent diffusivities at the scale of tens of meters. Numerical models provided information on local-scale diffusivities and feasible lithological features producing the observed tracer breakthrough curves. The combined approaches indicate significant anisotropy of bulk-scale diffusivity, likely associated with high-diffusivity layers. Both approaches indicated that diffusivities in some intervals were greater than expected from standard models relating porosity to diffusivity. High apparent diffusivities and anisotropic diffusivity structures were consistent with previous observations at the study site of rapid lateral transport and limited vertical spreading of gas-phase contaminants. Additional processes such as advective oscillations may be involved. These results indicate that gases in deep, layered unsaturated zone sediments can spread laterally more quickly, and produce higher peak concentrations, than predicted by homogeneous, isotropic diffusion models.

  12. Transformative Reduction of Transportation Greenhouse Gas Emissions. Opportunities for Change in Technologies and Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vimmerstedt, Laura [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brown, Austin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Newes, Emily [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Markel, Tony [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schroeder, Alex [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Yimin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chipman, Peter [U.S. Department of Transportation, Washington, D.C. (United States); Johnson, Shawn [U.S. Department of Transportation, Washington, D.C. (United States)

    2015-04-30

    The transportation sector is changing, influenced by concurrent, ongoing, dynamic trends that could dramatically affect the future energy landscape, including effects on the potential for greenhouse gas emissions reductions. Battery cost reductions and improved performance coupled with a growing number of electric vehicle model offerings are enabling greater battery electric vehicle market penetration, and advances in fuel cell technology and decreases in hydrogen production costs are leading to initial fuel cell vehicle offerings. Radically more efficient vehicles based on both conventional and new drivetrain technologies reduce greenhouse gas emissions per vehicle-mile. Net impacts also depend on the energy sources used for propulsion, and these are changing with increased use of renewable energy and unconventional fossil fuel resources. Connected and automated vehicles are emerging for personal and freight transportation systems and could increase use of low- or non-emitting technologies and systems; however, the net effects of automation on greenhouse gas emissions are uncertain. The longstanding trend of an annual increase in transportation demand has reversed for personal vehicle miles traveled in recent years, demonstrating the possibility of lower-travel future scenarios. Finally, advanced biofuel pathways have continued to develop, highlighting low-carbon and in some cases carbon-negative fuel pathways. We discuss the potential for transformative reductions in petroleum use and greenhouse gas emissions through these emerging transportation-sector technologies and trends and present a Clean Transportation Sector Initiative scenario for such reductions, which are summarized in Table ES-1.

  13. Thermodynamic Modeling of Gas Transport in Glassy Polymeric Membranes.

    Science.gov (United States)

    Minelli, Matteo; Sarti, Giulio Cesare

    2017-08-19

    Solubility and permeability of gases in glassy polymers have been considered with the aim of illustrating the applicability of thermodynamically-based models for their description and prediction. The solubility isotherms are described by using the nonequilibrium lattice fluid (NELF) (model, already known to be appropriate for nonequilibrium glassy polymers, while the permeability isotherms are described through a general transport model in which diffusivity is the product of a purely kinetic factor, the mobility coefficient, and a thermodynamic factor. The latter is calculated from the NELF model and mobility is considered concentration-dependent through an exponential relationship containing two parameters only. The models are tested explicitly considering solubility and permeability data of various penetrants in three glassy polymers, PSf, PPh and 6FDA-6FpDA, selected as the reference for different behaviors. It is shown that the models are able to calculate the different behaviors observed, and in particular the permeability dependence on upstream pressure, both when it is decreasing as well as when it is increasing, with no need to invoke the onset of additional plasticization phenomena. The correlations found between polymer and penetrant properties with the two parameters of the mobility coefficient also lead to the predictive ability of the transport model.

  14. Noble Gas Surface Flux Simulations And Atmospheric Transport

    Energy Technology Data Exchange (ETDEWEB)

    Carrigan, Charles R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sun, Yunwei [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simpson, Matthew D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-30

    Signatures from underground nuclear explosions or UNEs are strongly influenced by the containment regime surrounding them. The degree of gas leakage from the detonation cavity to the surface obviously affects the magnitude of surface fluxes of radioxenon that might be detected during the course of a Comprehensive Test Ban Treaty On-Site Inspection. In turn, the magnitude of surface fluxes will influence the downwind detectability of the radioxenon atmospheric signature from the event. Less obvious is the influence that leakage rates have on the evolution of radioxenon isotopes in the cavity or the downwind radioisotopic measurements that might be made. The objective of this letter report is to summarize our attempt to better understand how containment conditions affect both the detection and interpretation of radioxenon signatures obtained from sampling at the ground surface near an event as well as at greater distances in the atmosphere. In the discussion that follows, we make no attempt to consider other sources of radioactive noble gases such as natural backgrounds or atmospheric contamination and, for simplicity, only focus on detonation-produced radioxenon gases. Summarizing our simulations, they show that the decay of radioxenon isotopes (e.g., Xe-133, Xe-131m, Xe-133m and Xe-135) and their migration to the surface following a UNE means that the possibility of detecting these gases exists within a window of opportunity. In some cases, seeps or venting of detonation gases may allow significant quantities to reach the surface and be released into the atmosphere immediately following a UNE. In other release scenarios – the ones we consider here – hours to days may be required for gases to reach the surface at detectable levels. These release models are most likely more characteristic of “fully contained” events that lack prompt venting, but which still leak gas slowly across the surface for periods of months.

  15. Gas generation phenomena in radioactive waste transportation packaging

    International Nuclear Information System (INIS)

    Nigrey, P.J.

    1998-01-01

    The interaction of radiation from radioactive materials with the waste matrix can lead to the deterioration of the waste form resulting in the possible of gaseous species. Depending on the type and characteristics of the radiation source, the generation of hydrogen may predominate. Since the interaction of alpha particles with the waste form results in significant energy transfer, other gases such as carbon oxides, methane, nitrogen oxides, oxygen, water, and helium are possible. The type of gases produced from the waste forms is determined by the mechanisms involved in the waste degradation. For transuranic wastes, the identified degradation mechanisms are reported to be caused by radiolysis, thermal decomposition or dewatering, chemical corrosion, and bacterial action. While all these mechanisms may be responsible for the building of gases during the storage of wastes, radiolysis and thermal decomposition appear to be main contributors during waste transport operations. (authors)

  16. Effect of biochar on soil structural characteristics: water retention and gas transport

    DEFF Research Database (Denmark)

    Sun, Zhencai; Møldrup, Per; Vendelboe, Anders Lindblad

    Biochar addition to agricultural soil has been reported to reduce climate gas emission, as well as improve soil fertility and crop productivity. Little, however, is known about biochar effects on soil structural characteristics. This study investigates if biochar-application changes soil structural...... characteristics, as indicated from water retention and gas transport measurements on intact soil samples. Soil was sampled from a field experiment on a sandy loam with four control plots (C) without biochar and four plots (B) with incorporated biochar at a rate of 20 tons per hectare (plot size, 6 x 8 m). The C......-gas diffusivity on intact 100cm3 soil samples (5 replicates in each plot). We found that biochar application significantly decreased soil bulk density, hereby creating higher porosity. At the same soil-water matric potential, all the soil-gas phase parameters (air-filled porosity, air permeability and gas...

  17. Greenhouse gas emissions from the international maritime transport of New Zealand's imports and exports

    International Nuclear Information System (INIS)

    Fitzgerald, Warren B.; Howitt, Oliver J.A.; Smith, Inga J.

    2011-01-01

    Greenhouse gas emissions from international maritime transport are exempt from liabilities under the Kyoto Protocol. Research into quantifying these emissions is ongoing, and influences policy proposals to reduce emissions. This paper presents a cargo-based analysis of fuel consumption and greenhouse gas emissions from New Zealand's international maritime transport of goods. Maritime transport moves 99.5% (by mass) of New Zealand's internationally traded products. It is estimated that 73% of visiting vessels' activity can be directly attributed to the movement of goods in and out of New Zealand. A cargo-based methodology was used to estimate that the international maritime transport of New Zealand's imports and exports consumed 2.5 million tonnes (Mt; 2.6 billion litres) of fuel during the year 2007, which generated 7.7 Mt of carbon dioxide (CO 2 ) emissions. Double-counting of emissions would occur if a similar method was applied to all New Zealand's trading partners. In contrast, since few large vessels refuel in New Zealand, the National Greenhouse Gas Inventory listed 2007 international maritime transportation emissions as 0.98 Mt of CO 2 , calculated from fuel bunkered for international transport. The results, therefore, show a significant difference between activity-based and bunker-fuel methodologies in quantifying New Zealand's emissions. International policy implications are discussed. - Research highlights: → Cargo-based analysis of GHG emissions from New Zealand's international maritime transport of goods. → 7.7 Mt of CO 2 estimated from international maritime transport of NZ's 2007 imports and exports. → 73% of visiting vessels' 2007 activity attributed to the movement of goods in and out of NZ. → The results were significantly different from NZ's GHG Inventory bunker-fuel derived emissions figure. → Detailed approach for international transport emissions regional/national assessments described.

  18. Auction design for gas pipeline transportation capacity-The case of Nabucco and its open season

    International Nuclear Information System (INIS)

    Pickl, Matthias; Wirl, Franz

    2011-01-01

    As a response to the Russian dominance of the EU's natural gas supplies and the EU's increasing gas demands, major gas pipeline projects are currently under way to enhance the EU's energy supply security. Oftentimes to raise financing and to allocate gas transportation capacities, auctions are carried out to allow gas shippers to book transportation rights. In recent years, auctions have emerged as one of the most successful allocation mechanisms in the microeconomic theory. However, different auction designs can lead to different outcomes making the choice of auction design a decisive one, especially for divisible-good auctions. This paper seeks to give a formulation of an optimal auction design for gas pipeline transportation capacity. Specifically three different mechanisms are tested: (i) NPV allocation; (ii) pro rata allocation; and (iii) optimization. In addition, Nabucco is taken as a case study to empirically show results of such auction designs. Results show that a trade-off between revenue optimization and fair allocation can be observed: allocation per optimization is the favorable auction design when revenue maximization is more important than fair allocation. On the other hand, pro rata allocation is the auction design to be chosen when fairness of allocation is considered most central. - Research highlights: → Auction design for gas pipeline transportation capacity. → Empirical market-survey of Nabucco pipeline project auction as input data. → Testing of three different allocation mechanisms: (i) NPV allocation; (ii) pro rata allocation; and (iii) optimization. → Results show a trade-off between revenue optimization and fair allocation. → Allocation per optimization is the favorable auction design when revenue maximization is more important than fair allocation. → On the other hand, pro rata allocation is the auction design to be chosen when fairness of allocation is considered most central.

  19. Life cycle energy and greenhouse gas emissions from transportation of Canadian oil sands to future markets

    International Nuclear Information System (INIS)

    Tarnoczi, Tyler

    2013-01-01

    Oil sands transportation diversification is important for preventing discounted crude pricing. Current life cycle assessment (LCA) models that assess greenhouse gas (GHG) emissions from crude oil transportation are linearly-scale and fail to account for project specific details. This research sets out to develop a detailed LCA model to compare the energy inputs and GHG emissions of pipeline and rail transportation for oil sands products. The model is applied to several proposed oils sands transportation routes that may serve as future markets. Comparison between transportation projects suggest that energy inputs and GHG emissions show a high degree of variation. For both rail and pipeline transportation, the distance over which the product is transported has a large impact on total emissions. The regional electricity grid and pump efficiency have the largest impact on pipeline emissions, while train engine efficiency and bitumen blending ratios have the largest impact on rail transportation emissions. LCA-based GHG regulations should refine models to account for the range of product pathways and focus efforts on cost-effective emission reductions. As the climate-change impacts of new oil sands transportation projects are considered, GHG emission boundaries should be defined according to operation control. -- Highlights: •A life cycle model is developed to compare transportation of oil sands products. •The model is applied to several potential future oil sands markets. •Energy inputs and GHG emissions are compared. •Model inputs are explored using sensitivity analysis. •Policy recommendations are provided

  20. Rapid vertical trace gas transport by an isolated midlatitude thunderstorm

    Science.gov (United States)

    Hauf, Thomas; Schulte, Peter; Alheit, Reiner; Schlager, Hans

    1995-11-01

    During the cloud dynamics and chemistry field experiment CLEOPATRA in the summer of 1992 in southern Germany, the Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR) (German Aerospace Research Establishment) research aircraft Falcon traversed four times the anvil of a severe, isolated thunderstorm. The first two traverses were at 8 km altitude and close to the anvil cloud base, while the second two traverses were at 10 km. During the 8-km traverse, measured ozone mixing ratios dropped by 13 parts per billion by volume (ppbv) from the ambient cloud free environment to the anvil cloud, while water vapor increased by 0.3 g kg-1. At the 10-km traverses, ozone dropped by 25 ppbv, while water vapor increased by 0.18 g kg-1. Three-dimensional numerical thunderstorm simulations were performed to understand the cause of these changes. The simulations included the transport of two chemical inert tracers. Ozone was assumed to be one of them. The initial ozone profile was composed from an ozone routine sounding and the in situ Falcon measurements prior to the thunderstorm development. The second tracer is typical for a surface released pollutant with a nonzero, constant value in the boundary layer but zero above it. The redistribution of both tracers by the storm is calculated and compared with the observations. For the anvil penetration at 10 km, the calculated difference in ozone mixing ratios is 21 ppbv, while for water vapor an increase of 0.25 g kg-1 was found, in good agreement with the observations. To validate the model results, the radar reflectivity was calculated from simulated fields of cloud water, rain, graupel, hail, and snow and ice crystals and compared with observed values. With respect to maximum reflectivity values and spatial scales, again, excellent agreement was achieved. It is concluded that the rapid transport from the boundary layer directly into the anvil level is the most likely cause of the observed ozone decrease and water vapor increase

  1. PUC review of LDC gas purchasing practices and transportation agreements

    International Nuclear Information System (INIS)

    Lemon, R.

    1992-01-01

    The optimal paradigm for the PUC review of LDC purchasing and contracting starts with a regulatory paradigm that assigns risk upon the LDC. There are profits and risks in a market economy. Being exposed to risk causes firms to expend costs to minimize the risk, including lowering costs and altering input combinations. The transition within the industry implies greater need for planning, for optimization based on both economics and engineering, and less upon political directives. But the transition is far more encompassing than adding a new layer of regulatory oversight at the state level. States must revise their regulation to get out front - to give those incentives. The management audits will be internally profitable to the firms. If LDCs don't adjust, there will be other firms that will evaluate where poor management exists within this industry, and they will buy them out and lower the costs both for the profit they can obtain and to the betterment of ratepayers who experience lower rates. An a priori incentive process needs to govern PUC review of purchasing practices and transportation agreements. Lessons can be learned from the competitive market on how to structure this dynamic process which yields consumer benefits. This paper is organized as follows. First it identifies the forces which drive change - both historical bias and new options stemming from federal policy. Second, problems with 'improved' traditional regulatory review are discussed. Third, dimensions to an optimal PUC review process are set forth

  2. Sustainable Transportation Fuels from Natural Gas (H{sub 2}), Coal and Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Huffman, Gerald

    2012-12-31

    This research program is focused primarily on the conversion of coal, natural gas (i.e., methane), and biomass to liquid fuels by Fischer-Tropsch synthesis (FTS), with minimum production of carbon dioxide. A complementary topic also under investigation is the development of novel processes for the production of hydrogen with very low to zero production of CO{sub 2}. This is in response to the nation's urgent need for a secure and environmentally friendly domestic source of liquid fuels. The carbon neutrality of biomass is beneficial in meeting this goal. Several additional novel approaches to limiting carbon dioxide emissions are also being explored.

  3. Analysis and theory of gas transport in microporous sol-gel derived ceramic membranes

    NARCIS (Netherlands)

    de Lange, R.S.A.; de Lange, Rob; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.

    1995-01-01

    Sol-gel modification of mesoporous alumina membranes is a very successful technique to improve gas separation performance. Due to the formed microporous top layer, the membranes show activated transport and molecular sieve-like separation factors. This paper concentrates on the mechanism of

  4. Non-equilibrium reacting gas flows kinetic theory of transport and relaxation processes

    CERN Document Server

    Nagnibeda, Ekaterina; Nagnibeda, Ekaterina

    2009-01-01

    This volume develops the kinetic theory of transport phenomena and relaxation processes in the flows of reacting gas mixtures. The theory is applied to the modeling of non-equilibrium flows behind strong shock waves, in the boundary layer, and in nozzles.

  5. Open access natural gas transportation: A progress report on FERC implementation

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This article is a progress report on the Federal Energy Regulatory Commission's implementation of a US Court of Appeals decision upholding open access natural gas transportation. The five issues addressed by the court are identified and discussed. Take or Pay (TOP) contract modification, the crediting mechanism, pregranted abandonment, contract demand reduction, TOP cost passthrough are also discussed

  6. Spin-polarized transport in a two-dimensional electron gas with interdigital-ferromagnetic contacts

    DEFF Research Database (Denmark)

    Hu, C.-M.; Nitta, Junsaku; Jensen, Ane

    2001-01-01

    Ferromagnetic contacts on a high-mobility, two-dimensional electron gas (2DEG) in a narrow gap semiconductor with strong spin-orbit interaction are used to investigate spin-polarized electron transport. We demonstrate the use of magnetized contacts to preferentially inject and detect specific spi...

  7. An integrated transient model for simulating the operation of natural gas transport systems

    NARCIS (Netherlands)

    Pambour, Kwabena Addo; Bolado-Lavin, Ricardo; Dijkema, Gerard P. J.

    This paper presents an integrated transient hydraulic model that describes the dynamic behavior of natural gas transport systems (GTS). The model includes sub models of the most important facilities comprising a GTS, such as pipelines, compressor stations, pressure reduction stations, underground

  8. Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

    Science.gov (United States)

    Shimo, M.; Shimaya, S.; Maejima, T.

    2014-12-01

    Gas transport characteristics of fractured rocks is a great concern to variety of engineering applications such as underground storage of LPG, nuclear waste disposal, CCS and gas flooding in the oil field. Besides absolute permeability, relative permeability and capillary pressure as a function of water saturation have direct influences to the results of two phase flow simulation. However, number of the reported gas flow tests for fractured rocks are limited, therefore, the applicability of the conventional two-phase flow functions used for porous media, such as Mualem-van Genuchten model, to prediction of the gas transport in the fractured rock mass are not well understood. The authors conducted the two types of in-situ tests, with different scales, a borehole gas-injection test and a chamber gas-injection test in fractured granitic rock. These tests were conducted in the Cretaceous granitic rocks at the Namikata underground LPG storage cavern construction site in Ehime Prefecture in Japan, preceding to the cavern scale gas-tightness test. A borehole injection test was conducted using vertical and sub-vertical boreholes drilled from the water injection tunnel nearly at the depth of the top of the cavern, EL-150m. A new type downhole gas injection equipment that is capable to create a small 'cavern' within a borehole was developed. After performing a series of preliminary tests to investigate the hydraulic conductivity and gas-tightness, i.e. threshold pressure, gas injection tests were conducted under different gas pressure. Fig.1 shows an example of the test results From a chamber test using a air pressurizing chamber with volume of approximately166m3, the gas-tightness was confirmed within the uncertainty of 22Pa under the storage pressure of 0.7MPa, however, significant air leakage occurred possibly through an open fracture intersecting the chamber just after cavern pressure exceeds the initial hydrostatic pressure at the ceiling level of the chamber. Anomalies

  9. Profit, productivity, and price differential: an international performance comparison of the natural gas transportation industry

    International Nuclear Information System (INIS)

    Jeong-Dong Lee; Sung-Bae Park; Tai-Yoo Kim

    1999-01-01

    The objective of this paper is to evaluate the performance of natural gas transportation utilities, focusing on the three-key strategic performance measures of profit, productivity, and price differential. We propose a methodology that expresses the three performance measures in a unified single equation using the Edgeworth index. The proposed methodology is applied to an international comparison of the performance of 28 natural gas transportation utilities operating in eight countries in which the business environments differ greatly. The empirical results show the possible causes of performance differences and may shed some light on the direction of regulatory policy, especially for developing countries that have relatively short histories in the natural gas industry, such as Korea. (author)

  10. Liberalisation of EC gas transportation. A critical review of legal and policy arguments driving the discussion on third party access

    International Nuclear Information System (INIS)

    Walde, T.W.

    1992-01-01

    There is no integrated European gas market, but a number of national, quite tightly segregated and insulated gas markets. Gas is partly produced in these national markets (Netherlands, UK, less so in France and Germany) and imported from major, EC- and non-EC, gas exporters (countries emerging out of former USSR, Norway, Netherlands, Algeria, Libya). All European national gas markets are dominated by monopolies or quasi-monopolies controlling importation, transportation and local distribution; in some, particularly the French and South European gas markets, the gas business is controlled by public monopolies. In the United Kingdom, gas is dominated by a now private monopoly under the surveillance of a regulator - OfGas, whose duties include the oversight of competition in the gas industry in the UK and the task of facilitating direct purchases from gas producers (i.e. North Sea oil and gas companies) and traders. (author)

  11. Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII-D tilted neutral beam experiments

    Science.gov (United States)

    Waltz, R. E.; Bass, E. M.; Heidbrink, W. W.; VanZeeland, M. A.

    2015-11-01

    Recent experiments with the DIII-D tilted neutral beam injection (NBI) varying the beam energetic particle (EP) source profiles have provided strong evidence that unstable Alfven eigenmodes (AE) drive stiff EP transport at a critical EP density gradient [Heidbrink et al 2013 Nucl. Fusion 53 093006]. Here the critical gradient is identified by the local AE growth rate being equal to the local ITG/TEM growth rate at the same low toroidal mode number. The growth rates are taken from the gyrokinetic code GYRO. Simulation show that the slowing down beam-like EP distribution has a slightly lower critical gradient than the Maxwellian. The ALPHA EP density transport code [Waltz and Bass 2014 Nucl. Fusion 54 104006], used to validate the model, combines the low-n stiff EP critical density gradient AE mid-core transport with the Angioni et al (2009 Nucl. Fusion 49 055013) energy independent high-n ITG/TEM density transport model controling the central core EP density profile. For the on-axis NBI heated DIII-D shot 146102, while the net loss to the edge is small, about half the birth fast ions are transported from the central core r/a  <  0.5 and the central density is about half the slowing down density. These results are in good agreement with experimental fast ion pressure profiles inferred from MSE constrained EFIT equilibria.

  12. Characteristics of a gas-jet transport system for an on-line isotope separator

    International Nuclear Information System (INIS)

    Kawade, K.; Yamamoto, H.; Amano, H.; Hanada, M.; Katoh, T.; Okano, K.; Kawase, Y.; Fujiwara, I.

    1982-01-01

    Basic characteristics of a gas-jet transport system for an on-line isotope separator have been investigated using a 252 Cf source and a 235 U fission source. The transport efficiency of fission products through a capillary has been measured to be about 60% for the 235 U fission source. The sweep-out time of fission products through a target chamber and the transit time through a capillary have been measured for He, N 2 and CO 2 gases at several pressures. The measured sweep-out times have been almost equal to the exchange over time of the gas. The transit times have been found to be reasonably predicted by calculations. The transport system has been incorporated into the KUR-ISOL and is used for the study of short-lived nuclei. (orig.)

  13. North American natural gas long-term outlook : market and transportation opportunities

    International Nuclear Information System (INIS)

    Mahan, R.

    1998-01-01

    This study assessed the impact of major issues and trends on the market dynamics of the natural gas industry. A view of how these trends may evolve over the 1998 to 2015 period was also presented. The focus of the study is on market and transportation opportunities in Canada and the United States and their relationship in terms of supply, demand and gas flows between large aggregated regions. Key issues addressed in the report include: (1) the impacts of new transportation capacity on the flow of gas among supply and demand regions, (2) the impact of deregulation and environmental issues on the demand for gas in the electricity generation sector, and (3) the impacts of technological innovations on supply cost and size of the resource base. The report predicts a steady increase ( about 2 per cent annually) in demand for natural gas in Canada over the projection period (i.e. 1998-2015). Highest growth rates are likely to occur in the use of natural gas to generate electricity. While Alberta will remain pre-eminent among producing regions, British Columbia and resource areas off Canada's East Coast will also significantly increase their share of Canada's total production. 36 refs., 64 tabs., 46 figs

  14. Three mechanisms model of shale gas in real state transport through a single nanopore

    Science.gov (United States)

    Li, Dongdong; Zhang, Yanyu; Sun, Xiaofei; Li, Peng; Zhao, Fengkai

    2018-02-01

    At present, the apparent permeability models of shale gas consider only the viscous flow and Knudsen diffusion of free gas, but do not take into account the influence of surface diffusion. Moreover, it is assumed that shale gas is in ideal state. In this paper, shale gas is assumed in real state, a new apparent permeability model for shale gas transport through a single nanopore is developed that captures many important migration mechanisms, such as viscous flow and Knudsen diffusion of free gas, surface diffusion of adsorbed gas. According to experimental data, the accuracy of apparent permeability model was verified. What’s more, the effects of pressure and pore radius on apparent permeability, and the effects on the permeability fraction of viscous flow, Knudsen diffusion and surface diffusion were analysed, separately. Finally, the results indicate that the error of the developed model in this paper was 3.02%, which is less than the existing models. Pressure and pore radius seriously affect the apparent permeability of shale gas. When the pore radius is small or pressure is low, the surface diffusion cannot be ignored. When the pressure and the pore radius is big, the viscous flow occupies the main position.

  15. Cold flame on Biofilm - Transport of Plasma Chemistry from Gas to Liquid Phase

    Science.gov (United States)

    Kong, Michael

    2014-10-01

    One of the most active and fastest growing fields in low-temperature plasma science today is biological effects of gas plasmas and their translation in many challenges of societal importance such as healthcare, environment, agriculture, and nanoscale fabrication and synthesis. Using medicine as an example, there are already three FDA-approved plasma-based surgical procedures for tissue ablation and blood coagulation and at least five phase-II clinical trials on plasma-assisted wound healing therapies. A key driver for realizing the immense application potential of near room-temperature ambient pressure gas plasmas, commonly known as cold atmospheric plasmas or CAP, is to build a sizeable interdisciplinary knowledge base with which to unravel, optimize, and indeed design how reactive plasma species interact with cells and their key components such as protein and DNA. Whilst a logical objective, it is a formidable challenge not least since existing knowledge of gas discharges is largely in the gas-phase and therefore not directly applicable to cell-containing matters that are covered by or embedded in liquid (e.g. biofluid). Here, we study plasma inactivation of biofilms, a jelly-like structure that bacteria use to protect themselves and a major source of antimicrobial resistance. As 60--90% of biofilm is made of water, we develop a holistic model incorporating physics and chemistry in the upstream CAP-generating region, a plasma-exit region as a buffer for as-phase transport, and a downstream liquid region bordering the gas buffer region. A special model is developed to account for rapid chemical reactions accompanied the transport of gas-phase plasma species through the gas-liquid interface and for liquid-phase chemical reactions. Numerical simulation is used to illustrate how key reactive oxygen species (ROS) are transported into the liquid, and this is supported with experimental data of both biofilm inactivation using plasmas and electron spin spectroscopy (ESR

  16. Barometric gas transport along faults and its application to nuclear test-ban monitoring

    International Nuclear Information System (INIS)

    Carrigan, C.R.; Heinle, R.A.; Hudson, G.M.; Nitao, J.J.; Zucca, J.J.

    1997-05-01

    Underground nuclear explosions produce a unique but evanescent set of radionuclide gases that potentially can be used in the context of an on-site, test-ban monitoring program to differentiate them from other detected events such as earthquakes or mining activity. In Part I of this report we describe an experiment to evaluate the upward transport of gases from an underground explosion using two gas tracers with very different diffusivities that were released in a 400-m-deep, chemical explosive detonation. The less diffusive (more massive) tracer was detected on a nearby geologic fault 50 days following the detonation while the more diffusive tracer was detected 375 days after release. Computer simulations indicate that the arrival time and the chromatographic behavior of transport are characteristic of barometrically induced flow in a fractured, porous matrix regime. For a hypothetical 1-kiloton fission explosion subject to the same weather and gas transport conditions of the chemical explosion, simulations predict the detectability of argon-37 after 80 days in spite of depletion by radioactive decay. Largely because of the earlier arrival of xenon-133, owing to its lower binary gas diffusivity, the exceedingly short lived isotope should also be detectable - arriving about 30 days earlier than argon. In Part II we consider that our prediction of the detectability of argon and xenon is based upon the small volume (0.00001 m 3 ) sampling technique of the NPE tracer-gas sampling study while actual sampling for radionuclides would involve drawing much larger volume (possibly 0.1-1 m 3 ) gas samples from the near-surface. Extraction of such a large volume of gas from 1-5 meter depths in the soil raises the possibility of significant atmospheric infiltration, leading to substantial dilution of the extracted gas sample. However, an infiltration experiment suggests that significant dilution would not, in fact, occur at the most prolific sampling stations of the earlier gas

  17. Preliminary assessment of the availability of U.S. natural gas resources to meet U.S. transportation energy demand

    International Nuclear Information System (INIS)

    Singh, M. K.; Moore, J. S.

    2002-01-01

    Recent studies have indicated that substitutes for conventional petroleum resources will be needed to meet U.S. transportation energy demand in the first half of this century. One possible substitute is natural gas which can be used as a transportation fuel directly in compressed natural gas or liquefied natural gas vehicles or as resource fuel for the production of hydrogen for fuel cell vehicles. This paper contains a preliminary assessment of the availability of U.S. natural gas resources to meet future U.S. transportation fuel demand. Several scenarios of natural gas demand, including transportation demand, in the U.S. to 2050 are developed. Natural gas resource estimates for the U. S. are discussed. Potential Canadian and Mexican exports to the U.S. are estimated. Two scenarios of potential imports from outside North America are also developed. Considering all these potential imports, U.S. natural gas production requirements to 2050 to meet the demand scenarios are developed and compared with the estimates of U.S. natural gas resources. The comparison results in a conclusion that (1) given the assumptions made, there are likely to be supply constraints on the availability of U.S. natural gas supply post-2020 and (2) if natural gas use in transportation grows substantially, it will have to compete with other sectors of the economy for that supply-constrained natural gas

  18. Nuclear GUI: a Graphical User Interface for 3D discrete ordinates neutral particle transport codes in the doors and BOT3P packages

    International Nuclear Information System (INIS)

    Saintagne, P.W.; Azmy, Y.Y.

    2005-01-01

    A GUI (Graphical User Interface) provides a graphical, interactive and intuitive link between the user and the software. It translates the user'actions into information, e.g; input data that is interpretable by the software. In order to develop an efficient GUI, it is important to master the target computational code. An initial version of a complete GUI for the DOORS and BOT3P packages for solving neutral particle transport problems in 3-dimensional geometry has been completed. This GUI is made of 4 components. The first component GipGui aims at handling cross-sections by mixing microscopic cross-sections from different libraries. The second component TORT-GUI provides the user a simple way to create or modify input files for the TORT codes that is a general purpose neutral transport code able to solve large problems with complex configurations. The third component GGTM-GUI prepares the data describing the problem configuration like the geometrical data, material assignment or key flux positions. The fourth component DTM3-GUI helps the user to visualize TORT results by providing data for a graphics post-processor

  19. Modeling gravity effects on water retention and gas transport characteristics in plant growth substrates

    DEFF Research Database (Denmark)

    Deepagoda Thuduwe Kankanamge Kelum, Chamindu; Jones, Scott B.; Tuller, Markus

    2014-01-01

    utilization to conserve energy and to limit transport costs, native materials mined on Moon or Mars are of primary interest for plant growth media in a future outpost, while terrestrial porous substrates with optimal growth media characteristics will be useful for onboard plant growth during space missions....... Due to limited experimental opportunities and prohibitive costs, liquid and gas behavior in porous substrates under reduced gravity conditions has been less studied and hence remains poorly understood. Based on ground-based measurements, this study examined water retention, oxygen diffusivity and air...... that estimates the gas percolation threshold based on the pore size distribution. The model successfully captured measured data for all investigated media and demonstrated the implications of the poorly-understood shift in gas percolation threshold with improved gas percolation in reduced gravity. Finally, using...

  20. Study of neutral hydrogen transport in LHD core plasmas based on high dynamic-range Balmer-α spectroscopy

    International Nuclear Information System (INIS)

    Fujii, K.; Goto, M.; Morita, S.

    2014-10-01

    The radial distributions of the neutral hydrogen atom density and pressure in the Large Helical Device (LHD) were studied. The atom density distribution was determined from a detailed analysis of the intensity-calibrated Balmer-α line profile while the pressure distribution was obtained with a simple one-dimensional analytical model. We determined for the first time the atom density at the center of a fusion-oriented plasma, which is approximately three orders smaller than that at the edge. On the contrary, the atom pressure changes only a factor of 10 from the edge to core regions. (author)

  1. On the development and benchmarking of an approach to model gas transport in fractured media with immobile water storage

    Science.gov (United States)

    Harp, D. R.; Ortiz, J. P.; Pandey, S.; Karra, S.; Viswanathan, H. S.; Stauffer, P. H.; Anderson, D. N.; Bradley, C. R.

    2017-12-01

    In unsaturated fractured media, the rate of gas transport is much greater than liquid transport in many applications (e.g., soil vapor extraction operations, methane leaks from hydraulic fracking, shallow CO2 transport from geologic sequestration operations, and later-time radionuclide gas transport from underground nuclear explosions). However, the relatively immobile pore water can inhibit or promote gas transport for soluble constituents by providing storage. In scenarios with constant pressure gradients, the gas transport will be retarded. In scenarios with reversing pressure gradients (i.e. barometric pressure variations) pore water storage can enhance gas transport by providing a ratcheting mechanism. Recognizing the computational efficiency that can be gained using a single-phase model and the necessity of considering pore water storage, we develop a Richard's solution approach that includes kinetic dissolution/volatilization of constituents. Henry's Law governs the equilibrium gaseous/aqueous phase partitioning in the approach. The approach is implemented in a development branch of the PFLOTRAN simulator. We verify the approach with analytical solutions of: (1) 1D gas diffusion, (2) 1D gas advection, (3) sinusoidal barometric pumping of a fracture, and (4) gas transport along a fracture with uniform flow and diffusive walls. We demonstrate the retardation of gas transport in cases with constant pressure gradients and the enhancement of gas transport with reversing pressure gradients. The figure presents the verification of our approach to the analytical solution of barometric pumping of a fracture from Nilson et al (1991) where the x-axis "Horizontal axis" is the distance into the matrix block from the fracture.

  2. Improving estimates of subsurface gas transport in unsaturated fractured media using experimental Xe diffusion data and numerical methods

    Science.gov (United States)

    Ortiz, J. P.; Ortega, A. D.; Harp, D. R.; Boukhalfa, H.; Stauffer, P. H.

    2017-12-01

    Gas transport in unsaturated fractured media plays an important role in a variety of applications, including detection of underground nuclear explosions, transport from volatile contaminant plumes, shallow CO2 leakage from carbon sequestration sites, and methane leaks from hydraulic fracturing operations. Gas breakthrough times are highly sensitive to uncertainties associated with a variety of hydrogeologic parameters, including: rock type, fracture aperture, matrix permeability, porosity, and saturation. Furthermore, a couple simplifying assumptions are typically employed when representing fracture flow and transport. Aqueous phase transport is typically considered insignificant compared to gas phase transport in unsaturated fracture flow regimes, and an assumption of instantaneous dissolution/volatilization of radionuclide gas is commonly used to reduce computational expense. We conduct this research using a twofold approach that combines laboratory gas experimentation and numerical modeling to verify and refine these simplifying assumptions in our current models of gas transport. Using a gas diffusion cell, we are able to measure air pressure transmission through fractured tuff core samples while also measuring Xe gas breakthrough measured using a mass spectrometer. We can thus create synthetic barometric fluctuations akin to those observed in field tests and measure the associated gas flow through the fracture and matrix pore space for varying degrees of fluid saturation. We then attempt to reproduce the experimental results using numerical models in PLFOTRAN and FEHM codes to better understand the importance of different parameters and assumptions on gas transport. Our numerical approaches represent both single-phase gas flow with immobile water, as well as full multi-phase transport in order to test the validity of assuming immobile pore water. Our approaches also include the ability to simulate the reaction equilibrium kinetics of dissolution

  3. Experimental Study on Methane Hydrate Formation and Transport from Emulsions in a “Gas Lift” Riser in a Flowloop

    OpenAIRE

    Pham , Trung-Kien; Cameirao , Ana ,; Herri , Jean-Michel; Glenat , Philippe

    2017-01-01

    Session : Flow Assurance: Transportability Strategies - GasHyDyn : Logiciel de simulation de la composition et de la stabilité des hydrates de gaz; International audience; Production of crude oil with natural gas and water at low temperature and high pressure favours conditions for gas hydrate formation which can cause many troubles, up to blockage of pipelines. This work deals with hydrate kinetics of crystallization and agglomeration together with slurry transport and deposition under flowi...

  4. Kinetic theory of neutrals in a bounded plasma slab with inhomogeneous temperature and density profile

    International Nuclear Information System (INIS)

    Tendler, M.B.; Agren, O.

    1982-01-01

    The transport of neutral hydrogen atoms in a hydrogen plasma slab is considered. The influence of the inhomogeneous ion temperature profile on the neutral density and distribution is discussed as well as the influence of the neutral edge energy, charge exchange, and ionization rates. The analytical solutions for the neutral density and distribution function are obtained and compared with the numerical results. The effects due to the inhomogeneous temperature profile are discussed. The recommen-dations from the viewpoint of the effects mentioned previously for the purposes of the cold-gas mantle system have been given

  5. Pore size distribution effect on rarefied gas transport in porous media

    Science.gov (United States)

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

    2017-11-01

    Gas transport phenomena in porous media are known to strongly influence the performance of devices such as gas separation membranes and fuel cells. Knudsen diffusion is a dominant flow regime in these devices since they have nanoscale pores. Many experiments have shown that these porous media have complex structures and pore size distributions; thus, the diffusion coefficient in these media cannot be easily assessed. Previous studies have reported that the characteristic pore diameter of porous media can be defined in light of the pore size distribution; however, tortuosity factor, which is necessary for the evaluation of diffusion coefficient, is still unknown without gas transport measurements or simulations. Thus, the relation between pore size distributions and tortuosity factors is required to obtain the gas transport properties. We perform numerical simulations to prove the relation between them. Porous media are numerically constructed while satisfying given pore size distributions. Then, the mean-square displacement simulation is performed to obtain the tortuosity factors of the constructed porous media.. This paper is based on results obtained from a project commissioned by the New Energy and Industrial Development Organization (NEDO).

  6. Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.

    2013-11-01

    Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 C to improve their performance as oxygen reduction catalysts in neutral pH solutions used in microbial fuel cells (MFCs). The ammonia treated ACs exhibited better catalytic performance in rotating ring-disk electrode tests than their untreated precursors, with the bituminous based AC most improved, with an onset potential of Eonset = 0.12 V (untreated, Eonset = 0.08 V) and n = 3.9 electrons transferred in oxygen reduction (untreated, n = 3.6), and the hardwood based AC (treated, E onset = 0.03 V, n = 3.3; untreated, Eonset = -0.04 V, n = 3.0). Ammonia treatment decreased oxygen content by 29-58%, increased nitrogen content to 1.8 atomic %, and increased the basicity of the bituminous, peat, and hardwood ACs. The treated coal based AC cathodes had higher maximum power densities in MFCs (2450 ± 40 mW m-2) than the other AC cathodes or a Pt/C cathode (2100 ± 1 mW m-2). These results show that reduced oxygen abundance and increased nitrogen functionalities on the AC surface can increase catalytic performance for oxygen reduction in neutral media. © 2013 Elsevier B.V. All rights reserved.

  7. A liquefied energy chain for transport and utilization of natural gas for power production with CO2 capture and storage - Part 4: Sensitivity analysis of transport pressures and benchmarking with conventional technology for gas transport

    International Nuclear Information System (INIS)

    Aspelund, Audun; Gundersen, Truls

    2009-01-01

    A novel energy and cost effective transport chain for stranded natural gas utilized for power production with CO 2 capture and storage is developed. It includes an offshore section, a combined gas carrier and an integrated receiving terminal. In the offshore section, natural gas (NG) is liquefied to LNG by liquid carbon dioxide (LCO 2 ) and liquid inert nitrogen (LIN), which are used as cold carriers. In the onshore process, the cryogenic exergy in the LNG is utilized to cool and liquefy the cold carriers, LCO 2 and LIN. The transport pressures for LNG, LIN and LCO 2 will influence the thermodynamic efficiency as well as the ship utilization; hence sensitivity analyses are performed, showing that the ship utilization for the payload will vary between 58% and 80%, and the transport chain exergy efficiency between 48% and 52%. A thermodynamically optimized process requires 319 kWh/tonne LNG. The NG lost due to power generation needed to operate the LEC processes is roughly one third of the requirement in a conventional transport chain for stranded NG gas with CO 2 capture and sequestration (CCS)

  8. Atmospheric occurrence, transport and gas-particle partitioning of polychlorinated biphenyls over the northwestern Pacific Ocean

    Science.gov (United States)

    Wu, Zilan; Lin, Tian; Li, Zhongxia; Li, Yuanyuan; Guo, Tianfeng; Guo, Zhigang

    2017-10-01

    Ship-board air samples were collected during March to May 2015 from the East China Sea (ECS) to the northwestern Pacific Ocean (NWP) to explore the atmospheric occurrence and gas-particle partitioning of polychlorinated biphenyls (PCBs) when the westerly East Asian Monsoon prevailed. Total PCB concentrations in the atmosphere ranged from 56.8 to 261 pg m-3. Higher PCB levels were observed off the coast and minor temperature-induced changes showed that continuous emissions from East Asia remain as an important source to the regional atmosphere. A significant relationship between Koa (octanol-air partition coefficient) and KP (gas-particle partition coefficient) for PCBs was observed under continental air masses, suggesting that land-derived organic aerosols affected the PCB gas-particle partitioning after long-range transport, while an absence of this correlation was identified in marine air masses. The PCB partitioning cannot be fully explained by the absorptive mechanism as the predicted KP were found to be 2-3 orders of magnitude lower than the measured Kp, while the prediction was closely matched when soot adsorption was considered. The results suggested the importance of soot carbon as a transport medium for PCBs during their long-range transport and considerable impacts of continental outflows on PCBs across the downwind area. The estimated transport mass of particulate PCBs into the ECS and NWP totals 2333 kg during the spring, constituting ca. 17% of annual emission inventories of unintentionally produced PCB in China.

  9. Application of CFRP with High Hydrogen Gas Barrier Characteristics to Fuel Tanks of Space Transportation System

    Science.gov (United States)

    Yonemoto, Koichi; Yamamoto, Yuta; Okuyama, Keiichi; Ebina, Takeo

    In the future, carbon fiber reinforced plastics (CFRPs) with high hydrogen gas barrier performance will find wide applications in all industrial hydrogen tanks that aim at weight reduction; the use of such materials will be preferred to the use of conventional metallic materials such as stainless steel or aluminum. The hydrogen gas barrier performance of CFRP will become an important issue with the introduction of hydrogen-fuel aircraft. It will also play an important role in realizing fully reusable space transportation system that will have high specific tensile CFRP structures. Such materials are also required for the manufacture of high-pressure hydrogen gas vessels for use in the fuel cell systems of automobiles. This paper introduces a new composite concept that can be used to realize CFRPs with high hydrogen gas barrier performance for applications in the cryogenic tanks of fully reusable space transportation system by the incorporation of a nonmetallic crystal layer, which is actually a dense and highly oriented clay crystal laminate. The preliminary test results show that the hydrogen gas barrier characteristics of this material after cryogenic heat shocks and cyclic loads are still better than those of other polymer materials by approximately two orders of magnitude.

  10. Fiscal 2000 survey report. Feasibility study of reciprocative transportation system for carbon dioxide and natural gas utilizing gas hydrate; 2000 nendo gas hidrate wo riyosuru nisanka tanso to tennen gas no kogo yuso system no kanosei chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    A reciprocative CO2/CH{sub 4} transportation system will constitute a foundation on which minor gas fields may be made good use of in the Asia-Pacific region. For the construction of such a system, a survey is conducted into key technologies of separating CO2 from combustion exhaust with the aid of the hydrate process, reciprocative CO2/CH{sub 4} transportation with hydrate acting as medium, and subsurface CO2 storage and its utilization in minor gas fields or the like. The contents of the survey and the results fall in six areas, which are (1) the states of greenhouse gas reduction and natural gas utilization, (2) reciprocative CO2/CH{sub 4} transportation with hydrate acing as medium, (3) CO2 separation from combustion exhaust with the aid of the hydrate process, (4) reciprocative CO2/CH{sub 4} transportation with hydrate acing as medium, (5) subsurface CO2 storage and its utilization in minor gas fields, and (6) the establishment of a reciprocative CO2/CH{sub 4} transportation system and the evaluation of its cost performance. (NEDO)

  11. The orphan transporter v7-3 (slc6a15) is a Na+-dependent neutral amino acid transporter (B0AT2)

    DEFF Research Database (Denmark)

    Bröer, Angelika; Tietze, Nadine; Kowalczuk, Sonja

    2006-01-01

    . The transporter is functionally and sequence related to B(0)AT1 (slc6a19) and was hence named B(0)AT2. Leucine, isoleucine, valine, proline and methionine were recognized by the transporter, with values of K(0.5) (half-saturation constant) ranging from 40 to 200 microM. Alanine, glutamine and phenylalanine were...

  12. Persistent effects of subsoil compaction on pore size distribution and gas transport in a loamy soil

    DEFF Research Database (Denmark)

    Berisso, Feto Esimo; Schjønning, Per; Keller, T

    2012-01-01

    included four repeated wheelings with ∼10 Mg wheel loads. Water retention characteristics (WRC), air permeability (ka) and gas diffusivity (Ds/Do) were measured. A dual-porosity model fitted the WRC well, and there was a reduction in the volume of macropores >30 μm in compacted compared with control soil...... for all soil depths. Averaged for all sampling depths and also for some individual depths, both ka and Ds/Do were significantly reduced by compaction. Gas transport measurements showed that the experimental soil was poorly aerated, with local anoxic conditions at water regimes around field capacity in all...

  13. Power Generation and Transportation Systems Research Department: 1992 annual status report (Gas Research Institute)

    International Nuclear Information System (INIS)

    Benedict, A.

    1992-09-01

    Activities of Gas Research Institute's Power Generation and Transportation Systems subprogram for the period between October 1, 1991 and September 30, 1992 are summarized. The particular project areas covered in the report are Cogeneration and Power Systems, Engine Technology and Component Development, Natural Gas Vehicles Research, and Electric Power Generation. For each project area a separate chapter is provided. Each chapter includes a rationale for funding the research effort, the goals and objectives to be achieved, a general statement on research accomplishments, and the strategy employed in the project area. Each chapter also contains a series of summary reports on the status of each contract

  14. CASCADER: An m-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Cawlfield, D.E.; Been, K.B.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-06-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or diffusion. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. This is volume two to the CASCADER series, titled CASCADR8. It embodies the concepts presented in volume one of this series. To properly understand how the CASCADR8 model works, the reader should read volume one first. This volume presents the input and output file structure for CASCADR8, and a set of realistic scenarios for buried sources of radon gas

  15. CASCADER: An M-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Cawlfield, D.E.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-09-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transport of parent and daughter radionuclides in soil, radionuclide decay may occur. This version of CASCADER called CASCADR9 starts with the concepts presented in volumes one and three of this series. For a proper understanding of how the model works, the reader should read volume one first. Also presented in this volume is a set of realistic scenarios for buried sources of radon gas, and the input and output file structure for CASCADER9

  16. Spatial Variations of Turbulent Properties of Neutral Hydrogen Gas in the Small Magellanic Cloud Using Structure-function Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nestingen-Palm, David; Stanimirović, Snežana; González-Casanova, Diego F.; Babler, Brian [Astronomy Department, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706-1582 (United States); Jameson, Katherine; Bolatto, Alberto, E-mail: sstanimi@astro.wisc.edu [Astronomy Department and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2017-08-10

    We investigate spatial variations of turbulent properties in the Small Magellanic Cloud (SMC) by using neutral hydrogen (H i) observations. With the goal of testing the importance of stellar feedback on H i turbulence, we define central and outer SMC regions based on the star formation rate (SFR) surface density, as well as the H i integrated intensity. We use the structure function and the velocity channel analysis to calculate the power-law index ( γ ) for both underlying density and velocity fields in these regions. In all cases, our results show essentially no difference in γ between the central and outer regions. This suggests that H i turbulent properties are surprisingly homogeneous across the SMC when probed at a resolution of 30 pc. Contrary to recent suggestions from numerical simulations, we do not find a significant change in γ due to stellar feedback as traced by the SFR surface density. This could be due to the stellar feedback being widespread over the whole of the SMC, but more likely due to a large-scale gravitational driving of turbulence. We show that the lack of difference between central and outer SMC regions cannot be explained by the high optical depth H I.

  17. There Will Be Gas: Gazprom's Transport Strategy in Europe

    International Nuclear Information System (INIS)

    Bros, Aurelie

    2015-10-01

    The key role played by Ukraine in the transport of Russian gas and the underground gas storage facilities are a legacy of the Soviet era. The collapse of the USSR forced the Russian Federation to formulate its own national energy strategy after the Soviet Republics and satellite states went independent, to readjust it over time and to define new relationships with these countries regarding the gas sector. The collapse also had the effect of complicating gas transport after 1991 - a reality that had never been a thorny issue before since Ukraine had been formerly integrated into the territory of the Soviet Union. From the mid-1990's onwards, Gazprom has repeatedly tried to control gas transit through Ukraine and other infrastructures from the Soviet era. This effort has been double-pronged: the acquisition of shares in the Ukrainian transit sector (100% owned by the Ukrainian state) and the creation of a joint venture in order to exercise indirect control over the network. Neither of these resulted in success. During the 2000's, especially after the 2004 Orange Revolution, most of the arguments between Ukraine and Russia were based on transit contract, supply agreements, gas debts and management of the transit network. Such a situation led Gazprom-with the support of the Russian government-to adopt a more assertive stance toward Ukraine, i.e. cutting off gas flows intended for Ukraine. The two most serious crises of this nature occurred in 2006 and 2009. Gazprom developed major projects in collaboration with European energy companies to diversify gas supply routes at a time when it anticipated a major increase in European gas demand and the import needs of Russian gas. The Nord Stream pipeline is certainly the best illustration of Gazprom's bypassing policy. From a Russian perspective, transporting gas through the Nord Stream pipeline is much more attractive than Ukraine as Gazprom thereby avoids political tensions, keeps control of the situation and

  18. Efficiency evaluation of gas fuelled and electric driven buses in the public transport sector

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, Tobias Alexander

    2013-07-01

    The following report evaluates the efficiency of gas fuelled and electric driven buses in the public transport sector on a theoretical basis. The results indicate that the combination of CHP power plants and electric driven buses reach an overall efficiency of about 51% throughout the production chain (Well-to-Wheel), including heat distribution losses. The overall Well-to-Wheel efficiency for conventional gas turbines without heat recovery decreases to around 28%. For gas fuelled buses the Well-to-Wheel efficiency is about 30%. The Co2-emissions are evaluated based on the example of a #Left Double Quotation Mark#Volvo B10L CNG#Right Double Quotation Mark# gas bus and the electric driven #Left Double Quotation Mark#Eurabus 600#Right Double Quotation Mark#. The low energy consumption of the electric driven bus results in Co2-emissions of only 181.4 g Co2/km (Grid-to-Wheel). Depending on the utilised power plant technology the overall Co2-emissions (Well-to-Wheel) amount to 307.5 g Co2/km for a CHP power plant and 553.5 g Co2/km for a conventional gas turbine. On the other hand, gas fuelled buses emit about 1.25 kg Co2/km (Tank-to-Wheel), which is eightfold the emissions of an electrical bus. The Well-to-Tank emissions further increase to about 1.32 kg Co2/km. The emission calculation is based on real gas consumption data from a Norwegian public transport utility. The results indicate that the combination of CHP plants and electrical buses provide a much higher efficiency while reducing Co2-emissions. (author)

  19. CNG (compressed natural gas) as fuel for the transport sector in Trinidad and Tobago

    Energy Technology Data Exchange (ETDEWEB)

    So`Brien, G.C.; Persad, P.; Satcunanathan, S. [University of the West Indies, St. Augustine (Trinidad)

    1996-08-01

    Several studies have established that Trinidad and Tobago is well positioned to consider the substitution of compressed natural gas (CNG) for gasoline or diesel in the transport sector. Consequently a programme of conversion of private motors was initiated. Despite considerable advertisement programs projecting CNG as an environmentally friendly and cheap fuel, there is not yet widespread acceptance of the technology. The reasons for this are analysed. It is recommended that the policy of CNG usage be reviewed and the emphasis be shifted to transport fleets. It is also recommended that tax credits be considered as an incentive to users. (author)

  20. Gas transport through porous media; Sur le transport des gaz a travers les milieux poreux

    Energy Technology Data Exchange (ETDEWEB)

    Breton, J P [Commissariat a l' Energie Atomique Saclay (France). Centre d' Etudes Nucleaires

    1968-06-01

    In the first part of this work we derive a rigorous transport theory for a mixture of gases passing through a bed of spheres, when the temperature is uniform. We solve the Boltzmann equation, putting boundary conditions in the solution. Two different methods are used, according to the nature of the flow. The second part deals with the experimental work: measurements of permeability, of separation and of interdiffusion. In the last part, with the help of the new theory presented here, we are for the first time able to explain all the experimental data. (author) [French] Dans la premiere partie de ce travail nous developpons une theorie rigoureuse du transport d'un melange de gaz a travers un lit de spheres, quand la temperature est uniforme. Nous integrons l'equation de Boltzmann en introduisant des conditions aux limites dans la solution. Nous utilisons deux methodes differentes selon le regime d'ecoulement. La seconde partie est consacree a l'etude experimentale: mesures de permeametrie, de separation et d'interdiffusion. Dans la derniere partie, a l'aide de la nouvelle theorie developpee ici, nous expliquons tous les resultats experimentaux, ce qui n'avait pas ete fait jusque la. (auteur)

  1. Transport, atom blockade, and output coupling in a Tonks-Girardeau gas

    International Nuclear Information System (INIS)

    Rutherford, L.; McCann, J. F.; Goold, J.; Busch, Th.

    2011-01-01

    Recent experiments have demonstrated how quantum-mechanical impurities can be created within strongly correlated quantum gases and used to probe the coherence properties of these systems [S. Palzer, C. Zipkes, C. Sias, and M. Koehl, Phys. Rev. Lett. 103, 150601 (2009).]. Here we present a phenomenological model to simulate such an output coupler for a Tonks-Girardeau gas that shows qualitative agreement with the experimental results for atom transport and output coupling. Our model allows us to explore nonequilibrium transport phenomena in ultracold quantum gases and leads us to predict a regime of atom blockade, where the impurity component becomes localized in the parent cloud despite the presence of gravity. We show that this provides a stable mixed-species quantum gas in the strongly correlated limit.

  2. Physics and modelling of scrape-off layer transport

    International Nuclear Information System (INIS)

    Cohen, R.H.; Allen, S.L.; Crotinger, J.A.; Kaiser, T.B.; Milovich, J.L.; Mattor, N.; Nevins, W.M.; Porter, G.D.; Rensink, M.E.; Rognlien, T.D.; Berk, H.L.; Diamond, P.H.; Rosenbluth, M.N.; Hinton, F.L.; Staebler, G.M.; Knoll, D.A.; Modi, B.; Xu, X.Q.; Prinja, A.K.; Ryutov, D.D.; Tsidulko, Y.A.

    1992-01-01

    We present studies of three schemes for reducing the peak heat flux on divertor plates, divertor biasing, impurity injection (''radiative divertor'') and neutral gas injection (''gas target divertor''). We report on theoretical analysis of a likely source of turbulent transport in the SOL and incorporation of the resultant transport coefficients into self-consistent models

  3. Plasma neutralizer for H- beams

    International Nuclear Information System (INIS)

    Grossman, M.W.

    1977-01-01

    Neutralization of H - beams by a hydrogen plasma is discussed. Optimum target thickness and maximum neutralization efficiency as a function of the fraction of the hydrogen target gas ionized is calculated for different H - beam energies. Also, the variation of neutralization efficiency with respect to target thickness for different H - beam energies is computed. The dispersion of the neutralized beam by a magnetic field for different energies and different values of B . z is found. Finally, a type of plasma jet is proposed, which may be suitable for a compact H - neutralizer

  4. Liquefied natural gas as a transportation fuel for heavy-duty trucks: Volume I

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This document contains Volume 1 of a three-volume manual designed for use with a 2- to 3-day liquefied natural gas (LNG) training course. Transportation and off-road agricultural, mining, construction, and industrial applications are discussed. This volume provides a brief introduction to the physics and chemistry of LNG; an overview of several ongoing LNG projects, economic considerations, LNG fuel station technology, LNG vehicles, and a summary of federal government programs that encourage conversion to LNG.

  5. Gas Phase Transport, Adsorption and Surface Diffusion in Porous Glass Membrane

    Czech Academy of Sciences Publication Activity Database

    Yang, J.; Čermáková, Jiřina; Uchytil, Petr; Hamel, Ch.; Seidel-Morgenstern, A.

    2005-01-01

    Roč. 104, 2-4 (2005), s. 344-351 ISSN 0920-5861. [International Conference on Catalysis in Membrane Reactors /6./. Lahnstein, 06.07.2004-09.07.2004] R&D Projects: GA AV ČR(CZ) IAA4072402 Institutional research plan: CEZ:AV0Z40720504 Keywords : gas phase transport * vycor glass * adsorption Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.365, year: 2005

  6. Definition of neutral gas density according to the ''Interkosmos-4'' satellite measurements of solar radiation absorption in the 1-8A range

    International Nuclear Information System (INIS)

    Zonnemann, G.; Lippert, V.; Fel'ske, D.

    1980-01-01

    Measurements of the flux of solar irradiation in the range of 1-8 A have been carried out using the ''Interkosmos-4'' satellite. The data obtained during sunsets are used to determine neutral gas density at the altitudes of 80-135 km. Dependence of the effective cross section of solar irradiation absorption in ionosphere on the temperature of the Sun irradiation is given. Estimation of accuracy of the technique applied is presented. It turned out that during determination of absolute value of inert gas density and with its accordance to the altitude considerable errors appear, which do not affect the general density run in the limits of one profile. The profiles have characteristic decay of density at the altitudes of 105-115 km. The data obtained are compared with the measurements carried out simultaneously in the Lsub(α) line, the results of which show excessive absorption of irradiation at the altitudes higher than 100 km, which is explained by the effect of the second absorber, H 2 O most probably

  7. Transport of Gas Phase Radionuclides in a Fractured, Low-Permeability Reservoir

    Science.gov (United States)

    Cooper, C. A.; Chapman, J.

    2001-12-01

    The U.S. Atomic Energy Commission (predecessor to the Department of Energy, DOE) oversaw a joint program between industry and government in the 1960s and 1970s to develop technology to enhance production from low-permeability gas reservoirs using nuclear stimulation rather than conventional means (e.g., hydraulic and/or acid fracturing). Project Rio Blanco, located in the Piceance Basin, Colorado, was the third experiment under the program. Three 30-kiloton nuclear explosives were placed in a 2134 m deep well at 1780, 1899, and 2039 m below the land surface and detonated in May 1973. Although the reservoir was extensively fractured, complications such as radionuclide contamination of the gas prevented production and subsequent development of the technology. Two-dimensional numerical simulations were conducted to identify the main transport processes that have occurred and are currently occurring in relation to the detonations, and to estimate the extent of contamination in the reservoir. Minor modifications were made to TOUGH2, the multiphase, multicomponent reservoir simulator developed at Lawrence Berkeley National Laboratories. The simulator allows the explicit incorporation of fractures, as well as heat transport, phase change, and first order radionuclide decay. For a fractured two-phase (liquid and gas) reservoir, the largest velocities are of gases through the fractures. In the gas phase, tritium and one isotope of krypton are the principle radionuclides of concern. However, in addition to existing as a fast pathway, fractures also permit matrix diffusion as a retardation mechanism. Another retardation mechanism is radionuclide decay. Simulations show that incorporation of fractures can significantly alter transport rates, and that radionuclides in the gas phase can preferentially migrate upward due to the downward gravity drainage of liquid water in the pores. This project was funded by the National Nuclear Security Administration, Nevada Operations Office

  8. Application of space-angle synthesis to two-dimensional neutral-particle transport problems of weapon physics

    International Nuclear Information System (INIS)

    Roberds, R.M.

    1975-01-01

    A space-angle synthesis (SAS) method has been developed for treating the steady-state, two-dimensional transport of neutrons and gamma rays from a point source of simulated nuclear weapon radiation in air. The method was validated by applying it to the problem of neutron transport from a point source in air over a ground interface, and then comparing the results to those obtained by DOT, a state-of-the-art, discrete-ordinates code. In the SAS method, the energy dependence of the Boltzmann transport equation was treated in the standard multigroup manner. The angular dependence was treated by expanding the flux in specially tailored trial functions and applying the method of weighted residuals which analytically integrated the transport equation over all angles. The weighted-residual approach was analogous to the conventional spherical-harmonics (P/sub N/) method with the exception that the tailored expansion allowed for more rapid convergence than a spherical-harmonics P 1 expansion and resulted in a greater degree of accuracy. The trial functions used in the expansion were odd and even combinations of selected trial solutions, the trial solutions being shaped ellipsoids which approximated the angular distribution of the neutron flux in one-dimensional space. The parameters which described the shape of the ellipsoid varied with energy group and the spatial medium, only, and were obtained from a one-dimensional discrete-ordinates calculation. Thus, approximate transport solutions were made available for all two-dimensional problems of a certain class by using tabulated parameters obtained from a single, one-dimensional calculation

  9. Multiscale pore structure and its effect on gas transport in organic-rich shale

    Science.gov (United States)

    Wu, Tianhao; Li, Xiang; Zhao, Junliang; Zhang, Dongxiao

    2017-07-01

    A systematic investigation of multiscale pore structure in organic-rich shale by means of the combination of various imaging techniques is presented, including the state-of-the-art Helium-Ion-Microscope (HIM). The study achieves insight into the major features at each scale and suggests the affordable techniques for specific objectives from the aspects of resolution, dimension, and cost. The pores, which appear to be isolated, are connected by smaller pores resolved by higher-resolution imaging. This observation provides valuable information, from the microscopic perspective of pore structure, for understanding how gas accumulates and transports from where it is generated. A comprehensive workflow is proposed based on the characteristics acquired from the multiscale pore structure analysis to simulate the gas transport process. The simulations are completed with three levels: the microscopic mechanisms should be taken into consideration at level I; the spatial distribution features of organic matter, inorganic matter, and macropores constitute the major issue at level II; and the microfracture orientation and topological structure are dominant factors at level III. The results of apparent permeability from simulations agree well with the values acquired from experiments. By means of the workflow, the impact of various gas transport mechanisms at different scales can be investigated more individually and precisely than conventional experiments.

  10. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. Q.

    1998-12-16

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions.

  11. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies

    International Nuclear Information System (INIS)

    Wang, M. Q.

    1998-01-01

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions

  12. Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation.

    Science.gov (United States)

    Fuoco, Alessio; Khdhayyer, Muhanned R; Attfield, Martin P; Esposito, Elisa; Jansen, Johannes C; Budd, Peter M

    2017-02-11

    Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H₂, O₂, N₂, CH₄, CO₂ were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability.

  13. Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation

    Directory of Open Access Journals (Sweden)

    Alessio Fuoco

    2017-02-01

    Full Text Available Metal-organic frameworks (MOFs were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1. Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8 and Copper benzene tricarboxylate ((HKUST-1, were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H2, O2, N2, CH4, CO2 were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability.

  14. Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation

    Science.gov (United States)

    Fuoco, Alessio; Khdhayyer, Muhanned R.; Attfield, Martin P.; Esposito, Elisa; Jansen, Johannes C.; Budd, Peter M.

    2017-01-01

    Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H2, O2, N2, CH4, CO2 were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability. PMID:28208658

  15. Mixed Finite Element Simulation with Stability Analysis for Gas Transport in Low-Permeability Reservoirs

    Directory of Open Access Journals (Sweden)

    Mohamed F. El-Amin

    2018-01-01

    Full Text Available Natural gas exists in considerable quantities in tight reservoirs. Tight formations are rocks with very tiny or poorly connected pors that make flow through them very difficult, i.e., the permeability is very low. The mixed finite element method (MFEM, which is locally conservative, is suitable to simulate the flow in porous media. This paper is devoted to developing a mixed finite element (MFE technique to simulate the gas transport in low permeability reservoirs. The mathematical model, which describes gas transport in low permeability formations, contains slippage effect, as well as adsorption and diffusion mechanisms. The apparent permeability is employed to represent the slippage effect in low-permeability formations. The gas adsorption on the pore surface has been described by Langmuir isotherm model, while the Peng-Robinson equation of state is used in the thermodynamic calculations. Important compatibility conditions must hold to guarantee the stability of the mixed method by adding additional constraints to the numerical discretization. The stability conditions of the MFE scheme has been provided. A theorem and three lemmas on the stability analysis of the mixed finite element method (MFEM have been established and proven. A semi-implicit scheme is developed to solve the governing equations. Numerical experiments are carried out under various values of the physical parameters.

  16. A risk analysis for gas transport network planning expansion under regulatory uncertainty in Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, C.; Wortmann, J.C. [Information System Cluster, Faculty of Economics and Business, Rijksuniversiteit Groningen, Landleven 5, Postbus 800, 9700 AV Groningen (Netherlands)

    2009-02-15

    The natural gas industry in Western Europe went through drastic changes induced by the unbundling of the national companies, followed by the liberalization of gas trade and the regulation of gas transmission. Natural gas transmission is operated through a network of interconnected grids, and is capacity constrained. Each of the grids is locally regulated in terms of price limits on transportation services. Local tariff differences may induce unnatural gas routing within a network, creating congestion in some part of it. This phenomena is referred to as the Jepma effect. Following Jepma (2001. Gaslevering onder druk. Stichting JIN. Available at: www.jiqweb.org (52pp) (in Dutch)) this may lead to misguided investment decisions. In this paper a multi-stage linear program is used to simulate the repartition of the natural gas flow in an interconnected grid system on a succession of contracting periods. By this simulation, the risk linked to infrastructure investment is assessed. The risk measured can be seen as the probability of a negative present net value for the investment. The model is applied on an example of two grids that are on alternative routes serving same destinations. When applied to a specific situation of North-West Europe (Germany and The Netherlands), the model clearly demonstrates that the risks turn out to be too high to invest: there are hardly any scenarios under which an acceptable ROI will be realized. Given the current tariff policy and current publicly available forecasts of demand and supply, it is unlikely that market forces will attract additional investments in transportation capacity. This reluctance to invest can be prohibitive for further growth of supply if the demand would increase significantly. (author)

  17. A risk analysis for gas transport network planning expansion under regulatory uncertainty in Western Europe

    International Nuclear Information System (INIS)

    Pelletier, C.; Wortmann, J.C.

    2009-01-01

    The natural gas industry in Western Europe went through drastic changes induced by the unbundling of the national companies, followed by the liberalization of gas trade and the regulation of gas transmission. Natural gas transmission is operated through a network of interconnected grids, and is capacity constrained. Each of the grids is locally regulated in terms of price limits on transportation services. Local tariff differences may induce unnatural gas routing within a network, creating congestion in some part of it. This phenomena is referred to as the Jepma effect. Following Jepma (2001. Gaslevering onder druk. Stichting JIN. Available at: www.jiqweb.org (52pp) (in Dutch)) this may lead to misguided investment decisions. In this paper a multi-stage linear program is used to simulate the repartition of the natural gas flow in an interconnected grid system on a succession of contracting periods. By this simulation, the risk linked to infrastructure investment is assessed. The risk measured can be seen as the probability of a negative present net value for the investment. The model is applied on an example of two grids that are on alternative routes serving same destinations. When applied to a specific situation of North-West Europe (Germany and The Netherlands), the model clearly demonstrates that the risks turn out to be too high to invest: there are hardly any scenarios under which an acceptable ROI will be realized. Given the current tariff policy and current publicly available forecasts of demand and supply, it is unlikely that market forces will attract additional investments in transportation capacity. This reluctance to invest can be prohibitive for further growth of supply if the demand would increase significantly. (author)

  18. Welfare distribution effect of a price reduction in the Dutch gas transport market: A scenario analysis of regulatory policy, market form and rent allocation

    NARCIS (Netherlands)

    A. Witteloostuijn, van (Arjen); S. Brakman (Steven); J.G.M. van Marrewijk (Charles)

    2007-01-01

    textabstractAs part of the larger energy market deregulation program, the Dutch energy authority—DTe—has developed the habit to force the Dutch gas transport enterprise—Gas Transport Services, or GTS—to lower its prices. DTe's key argument is that lower gas transport prices will benefit the

  19. Welfare distribution effect of a price reduction in the Dutch gas transport market: A scenario analysis of regulatory policy, market form and rent allocation

    NARCIS (Netherlands)

    Witteloostuijn , van Arjen; Brakman, S.; van Marrewijk, C.

    2007-01-01

    As part of the larger energy market deregulation program, the Dutch energy authority-DTe-has developed the habit to force the Dutch gas transport enterprise-Gas Transport Services, or GTS-to lower its prices. DTe's key argument is that lower gas transport prices will benefit the end-user. Indeed,

  20. Energy utilization and greenhouse-gas emissions: Transportation sector, topical report

    International Nuclear Information System (INIS)

    Darrow, K.G.

    1992-06-01

    The objective of the report is to compare the emissions of greenhouse gases for alternative end-use technologies in the transportation sector. Scientists assert that global warming is occurring and will continue to occur as a result of increasing concentrations of certain gases in the atmosphere. Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are the focus of this analysis because they are believed to cause three-fourths of the global warming effect and because energy production and use are a significant source of these emissions. Greenhouse gas emissions in the energy sector occur during energy production, conversion, transportation and end-use. This analysis compares alternative transportation sector fuel/technology choices in terms of their total fuel-cycle emissions of greenhouse gases. The emphasis of this report is on the end use comparison. The fuel-cycle emissions comparison was developed in a companion report

  1. Intense ion beam transport in magnetic quadrupoles: Experiments on electron and gas effects

    International Nuclear Information System (INIS)

    Seidl, P.A.; Molvik, A.W.; Bieniosek, F.M.; Cohen, R.H.; Faltens, A.; Friedman, A.; Kireef Covo, M.; Lund, S.M.; Prost, L.; Vay, J-L.

    2004-01-01

    Heavy-ion induction linacs for inertial fusion energy and high-energy density physics have an economic incentive to minimize the clearance between the beam edge and the aperture wall. This increases the risk from electron clouds and gas desorbed from walls. We have measured electron and gas emission from 1 MeV K + incident on surfaces near grazing incidence on the High-Current Experiment (HCX) at LBNL. Electron emission coefficients reach values >100, whereas gas desorption coefficients are near 10 4 . Mitigation techniques are being studied: A bead-blasted rough surface reduces electron emission by a factor of 10 and gas desorption by a factor of 2. We also discuss the results of beam transport (of 0.03-0.18 A K + ) through four pulsed room-temperature magnetic quadrupoles in the HCX at LBNL. Diagnostics are installed on HCX, between and within quadrupole magnets, to measure the beam halo loss, net charge and expelled ions, from which we infer gas density, electron trapping, and the effects of mitigation techniques. A coordinated theory and computational effort has made significant progress towards a self-consistent model of positive-ion beam and electron dynamics. We are beginning to compare experimental and theoretical results

  2. Regional disparity of urban passenger transport associated GHG (greenhouse gas) emissions in China: A review

    International Nuclear Information System (INIS)

    Hao, Han; Geng, Yong; Wang, Hewu; Ouyang, Minggao

    2014-01-01

    With China’s urbanization and motorization, greenhouse gas (GHG) emissions from urban passenger transport increased rapidly over recent years. As we estimated, China’s urban passenger transport associated motorized travel, energy consumption and lifecycle GHG emissions reached 2815 billion passenger kilometers (pkm), 77 million tons of oil equivalent (toe) and 335 million ton CO 2 equivalent in 2010, over half of which were located in eastern provinces. Over national level, GHG emissions by private passenger vehicles, business passenger vehicles, taxis, motorcycles, E-bikes, transit buses and urban rails accounted for 57.7%, 13.0%, 7.7%, 8.6%, 1.8%, 10.5% and 0.7% of the total. Significant regional disparity was observed. The province-level per capita GHG emissions ranged from 285 kg/capita in Guizhou to 1273 kg/capita in Beijing, with national average of 486 kg/capita. Depending on province context and local policy orientation, the motorization pathways of China’s several highest motorized provinces are quite diverse. We concluded that motorization rate and transport structure were the substantial factors determining urban passenger transport associated GHG emissions. Considering the great potential of urban passenger transport growth in China, policies guiding the optimization of transport structure should be in place with priority in eastern provinces. - Highlights: • Province-leveled motorized travel, energy consumption and GHG emissions in China were studied. • Significant regional disparities on urban passenger transport were observed. • Region-specific sustainable transport energy policies were discussed

  3. Using high temperature gas-cooled reactors for energy neutral mineral development processes – A proposed IAEA Coordinated Research Project

    International Nuclear Information System (INIS)

    Haneklaus, N.; Reitsma, F.; Tulsidas, H.; Dyck, G.; Koshy, T.; Tyobeka, B.; Schnug, E.; Allelein, H-J.; Birky, B.

    2014-01-01

    Today, uranium mined from various regions is the predominant reactor fuel of the present generation of nuclear power plants. The anticipated growth in nuclear energy may require introducing uranium/thorium from unconventional resources (e.g. phosphates, coal ash or sea water) as a future nuclear reactor fuel. The demand for mineral commodities is growing exponentially and high-grade, easily-extractable resources are being depleted rapidly. This shifts the global production to low-grade, or in certain cases unconventional mineral resources, the production of which is constrained by the availability of large amounts of energy. Numerous mining processes can benefit from the use of so-called “thermal processing”. This is in particular beneficial for (1) low grade deposits that cannot be treated using the presently dominant chemical processing techniques; (2) the extraction of high purity end products; and (3) the separation of high value or unwanted impurities (e.g. uranium, thorium, rare earths, etc.) that could be used/sold, when extracted, which will result in cleaner final products. The considerably lower waste products also make it attractive compared to chemical processing. In the future, we may need to extract nuclear fuel and minerals from the same unconventional resources to make nuclear fuel- and low grade ore processing feasible and cost-effective. These processes could be sustainable only if low-cost, carbon free, reliable energy is available for comprehensive extraction of all valuable commodities, for the entire life of the project. Nuclear power plants and specifically High Temperature Gas-cooled Reactors (HTGRs) can produce this energy and heat in a sustainable way, especially if enough uranium/thorium can be extracted to fuel these reactors.

  4. Heat transport and afterheat removal for gas cooled reactors under accident conditions

    International Nuclear Information System (INIS)

    2001-01-01

    The Co-ordinated Research Project (CRP) on Heat Transport and Afterheat Removal for Gas Cooled Reactors Under Accident Conditions was organized within the framework of the International Working Group on Gas Cooled Reactors (IWGGCR). This International Working Group serves as a forum for exchange of information on national programmes, provides advice to the IAEA on international co-operative activities in advanced technologies of gas cooled reactors (GCRs) and supports the conduct of these activities. Advanced GCR designs currently being developed are predicted to achieve a high degree of safety through reliance on inherent safety features. Such design features should permit the technical demonstration of exceptional public protection with significantly reduced emergency planning requirements. For advanced GCRs, this predicted high degree of safety largely derives from the ability of the ceramic coated fuel particles to retain the fission products under normal and accident conditions, the safe neutron physics behaviour of the core, the chemical stability of the core and the ability of the design to dissipate decay heat by natural heat transport mechanisms without reaching excessive temperatures. Prior to licensing and commercial deployment of advanced GCRs, these features must first be demonstrated under experimental conditions representing realistic reactor conditions, and the methods used to predict the performance of the fuel and reactor must be validated against these experimental data. Within this CRP, the participants addressed the inherent mechanisms for removal of decay heat from GCRs under accident conditions. The objective of this CRP was to establish sufficient experimental data at realistic conditions and validated analytical tools to confirm the predicted safe thermal response of advance gas cooled reactors during accidents. The scope includes experimental and analytical investigations of heat transport by natural convection conduction and thermal

  5. User's guide for TWOHEX: a code package for two-dimensional, neutral-particle transport in equilateral triangular meshes

    International Nuclear Information System (INIS)

    Walters, W.F.; Brinkley, F.W.; Marr, D.R.

    1984-10-01

    TWOHEX solves the two-dimensional multigroup transport equation on an equilateral triangular mesh in the x,y plane. Both regular and adjoint, inhomogeneous (fixed source) and homogeneous problems are solved. Three problem domains are treated by TWOHEX. The whole core domain is a 60 0 parallelogram with vacuum boundary conditions on each face. The third core domain is a 120 0 parallelogram with two vacuum and two rotational boundary conditions. The sixth core domain is a 60 0 parallelogram with two vacuum and two rotational boundary conditions. General anisotropic scattering is allowed and an anisotropic inhomogeneous source may be input as cell averages

  6. Vadose Zone Fate and Transport Simulation of Chemicals Associated with Coal Seam Gas Extraction

    Science.gov (United States)

    Simunek, J.; Mallants, D.; Jacques, D.; Van Genuchten, M.

    2017-12-01

    The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite element models for simulating the one-, and two- or three-dimensional movement of water, heat, and multiple solutes in variably-saturated media, respectively. While the standard HYDRUS models consider only the fate and transport of individual solutes or solutes subject to first-order degradation reactions, several specialized HYDRUS add-on modules can simulate far more complex biogeochemical processes. The objective of this presentation is to provide an overview of the HYDRUS models and their add-on modules, and to demonstrate applications of the software to the subsurface fate and transport of chemicals involved in coal seam gas extraction and water management operations. One application uses the standard HYDRUS model to evaluate the natural soil attenuation potential of hydraulic fracturing chemicals and their transformation products in case of an accidental release. By coupling the processes of retardation, first-order degradation and convective-dispersive transport of the biocide bronopol and its degradation products, we demonstrated how natural attenuation reduces initial concentrations by more than a factor of hundred in the top 5 cm of the vadose zone. A second application uses the UnsatChem module to explore the possible use of coal seam gas produced water for sustainable irrigation. Simulations with different irrigation waters (untreated, amended with surface water, and reverse osmosis treated) provided detailed results regarding chemical indicators of soil and plant health, notably SAR, EC and sodium concentrations. A third application uses the coupled HYDRUS-PHREEQC module to analyze trace metal transport involving cation exchange and surface complexation sorption reactions in the vadose zone leached with coal seam gas produced water following some accidental water release scenario. Results show that the main process responsible for trace metal migration is complexation of

  7. Revisiting low-fidelity two-fluid models for gas-solids transport

    Science.gov (United States)

    Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

    2016-08-01

    Two-phase gas-solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas-solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe-Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

  8. Analysis of neutral volatile aroma components in Tilsit cheese using a combination of dynamic headspace technique, capillary gas chromatography and mass spectrometry

    International Nuclear Information System (INIS)

    Dillinger, K.H.

    2000-03-01

    Tilsit cheese is made by the influence of lab ferment and starter cultures on milk. The ripening is done by repeated inoculation of the surface of the Tilsit cheese with yeasts and read smear cultures. This surface flora forms the typical aroma of the Tilsit cheese during the ripening process. The aim of the work was to receive general knowledge about the kind and amount of the neutral volatile aroma components of Tilsit cheese. Beyond this the ability of forming aroma components by read smear cultures and the dispersion of these components in cheese was to be examined. The results were intended to evaluate the formation of aroma components in Tilsit cheese. The semi-quantitative analyses of the aroma components of all samples were done by combining dynamic headspace extraction, gas chromatography and mass spectrometry. In this process the neutral volatile aroma components were extracted by dynamic headspace technique, adsorbed on a trap, thermally desorbed, separated by gas chromatography, detected and identified by mass spectrometry. 63 components belonging to the chemical classes of esters, ketones, aldehydes, alcohols and sulfur containing substances as well as aromatic hydrocarbons, chlorinated hydrocarbons and hydrocarbons were found in the analysed cheese samples of different Austrian Tilsit manufacturing plants. All cheese samples showed a qualitative equal but quantitative varied spectrum of aroma components. The cultivation of pure cultures on a cheese agar medium showed all analysed aroma components to be involved in the biochemical metabolism of these cultures. The ability to produce aroma components greatly differed between the strains and it was not possible to correlate this ability with the taxonomic classification of the strains. The majority of the components had a non-homogeneous concentration profile in the cheese body. This was explained by effects of diffusion and temporal and spatial different forming of components by the metabolism of the

  9. Bunched beam neutralization

    International Nuclear Information System (INIS)

    Gammel, G.M.; Maschke, A.W.; Mobley, R.M.

    1979-01-01

    One of the steps involved in producing an intense ion beam from conventional accelerators for Heavy Ion Fusion (HIF) is beam bunching. To maintain space charge neutralized transport, neutralization must occur more quickly as the beam bunches. It has been demonstrated at BNL that a 60 mA proton beam from a 750 kV Cockcroft--Walton can be neutralized within a microsecond. The special problem in HIF is that the neutralization must occur in a time scale of nanoseconds. To study neutralization on a faster time scale, a 40 mA, 450 kV proton beam was bunched at 16 MHz. A biased Faraday cup sampled the bunched beam at the position where maximum bunching was nominally expected, about 2.5 meters from the buncher. Part of the drift region, about 1.8 meters, was occupied by a series of Gabor lenses. In addition to enhancing beam transport by transverse focussing, the background cloud of electrons in the lenses provided an extra degree of neutralization. With no lens, the best bunch factor was at least 20. Bunch factor is defined here as the ratio of the distance between bunches to the FWHM bunch length. With the lens, it was hoped that the increased plasma frequency would decrease the neutralization time and cause an increase in the bunch factor. In fact, with the lens, the instantaneous current increased about three times, but the bunch factor dropped to about 10. Even with the lens, the FWHM of the bunches at the position of maximum bunching was still comparable to or less than the oscillation period of the surrounding electron plasma. Thus, the electron density in the lens must increase before neutralization could be effective in this case, or bunching should be done at a lower frequency

  10. Evaluation and analysis method for natural gas hydrate storage and transportation processes

    International Nuclear Information System (INIS)

    Hao Wenfeng; Wang Jinqu; Fan Shuanshi; Hao Wenbin

    2008-01-01

    An evaluation and analysis method is presented to investigate an approach to scale-up a hydration reactor and to solve some economic problems by looking at the natural gas hydrate storage and transportation process as a whole. Experiments with the methane hydration process are used to evaluate the whole natural gas hydrate storage and transportation process. The specific contents and conclusions are as follows: first, batch stirring effects and load coefficients are studied in a semi-continuous stirred-tank reactor. Results indicate that batch stirring and appropriate load coefficients are effective in improving hydrate storage capacity. In the experiments, appropriate values for stirring velocity, stirring time and load coefficient were found to be 320 rpm, 30 min and 0.289, respectively. Second, throughput and energy consumption of the reactor for producing methane hydrates are calculated by mass and energy balance. Results show that throughput of this is 1.06 kg/d, with a product containing 12.4% methane gas. Energy consumption is 0.19 kJ, while methane hydrates containing 1 kJ heat are produced. Third, an energy consumption evaluation parameter is introduced to provide a single energy consumption evaluation rule for different hydration reactors. Parameter analyses indicate that process simplicity or process integration can decrease energy consumption. If experimental gas comes from a small-scale natural gas field and the energy consumption is 0.02 kJ when methane hydrates containing 1 kJ heat are produced, then the decrease is 87.9%. Moreover, the energy consumption evaluation parameter used as an economic criterion is converted into a process evaluation parameter. Analyses indicate that the process evaluation parameter is relevant to technology level and resource consumption for a system, which can make it applicable to economic analysis and venture forecasting for optimal capital utilization

  11. THE HERSCHEL COMPREHENSIVE (U)LIRG EMISSION SURVEY (HERCULES): CO LADDERS, FINE STRUCTURE LINES, AND NEUTRAL GAS COOLING

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J. F.; Van der Werf, P. P.; Israel, F. P.; Meijerink, R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Aalto, S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Observatory, SE-43994 Onsala (Sweden); Armus, L.; Díaz-Santos, T. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Charmandaris, V. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, P. Penteli, 15236 Athens (Greece); Evans, A. S. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Fischer, J. [Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences (CAS), 2 West Beijing Road, Nanjing 210008 (China); González-Alfonso, E. [Departamento de Fsica y Matemáticas, Universidad de Alcalá, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Harris, A. I. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 16, Bonn, D-53121 (Germany); Isaak, K. G. [Scientific Support Office, ESTEC/SRE-S, Keplerlaan 1, NL-2201 AZ Noordwijk (Netherlands); Kramer, C., E-mail: rosenberg@strw.leidenuniv.nl [Instituto Radioastronomía Milimétrica (IRAM), Av. Divina Pastora 7, Nucleo Central, E-18012 Granada (Spain); and others

    2015-03-10

    (Ultra) luminous infrared galaxies ((U)LIRGs) are objects characterized by their extreme infrared (8-1000 μm) luminosities (L {sub LIRG} > 10{sup 11} L {sub ☉} and L {sub ULIRG} > 10{sup 12} L {sub ☉}). The Herschel Comprehensive ULIRG Emission Survey (PI: van der Werf) presents a representative flux-limited sample of 29 (U)LIRGs that spans the full luminosity range of these objects (10{sup 11} L {sub ☉} ≤ L {sub IR} ≤ 10{sup 13} L {sub ☉}). With the Herschel Space Observatory, we observe [C II] 157 μm, [O I] 63 μm, and [O I] 145 μm line emission with Photodetector Array Camera and Spectrometer, CO J = 4-3 through J = 13-12, [C I] 370 μm, and [C I] 609 μm with SPIRE, and low-J CO transitions with ground-based telescopes. The CO ladders of the sample are separated into three classes based on their excitation level. In 13 of the galaxies, the [O I] 63 μm emission line is self absorbed. Comparing the CO excitation to the InfraRed Astronomical Satellite 60/100 μm ratio and to far infrared luminosity, we find that the CO excitation is more correlated to the far infrared colors. We present cooling budgets for the galaxies and find fine-structure line flux deficits in the [C II], [Si II], [O I], and [C I] lines in the objects with the highest far IR fluxes, but do not observe this for CO 4 ≤ J {sub upp} ≤ 13. In order to study the heating of the molecular gas, we present a combination of three diagnostic quantities to help determine the dominant heating source. Using the CO excitation, the CO J = 1-0 linewidth, and the active galactic nucleus (AGN) contribution, we conclude that galaxies with large CO linewidths always have high-excitation CO ladders, and often low AGN contributions, suggesting that mechanical heating is important.

  12. Analysis and optimization of indicators of energy and resource consumption of gas turbine and electric drives for transportation of hydrocarbons

    Science.gov (United States)

    Golik, V. V.; Zemenkova, M. Yu; Seroshtanov, I. V.; Begalko, Z. V.

    2018-05-01

    The paper presents the results of the analysis of statistical indicators of energy and resource consumption in oil and gas transportation by the example of one of the regions of Russia. The article analyzes engineering characteristics of compressor station drives. Official statistical bulletins on the fuel and energy resources of the region in the pipeline oil and gas transportation system were used as the initial data.

  13. The contribution of diffusion to methane transport in deep underground gas deposits; Der Beitrag der Diffusion zum Methantransport in tiefliegenden Gas-Lagerstaetten

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, W. [Institut fuer Erdoel- und Erdgasforschung, Clausthal-Zellerfeld (Germany)

    1998-12-31

    Optimisation of gas production necessitates accurate knowledge of gas transport mechanisms. In view of the extreme temperatures, pressures, and permeability conditions of underground gas deposits, linear transfer of existing knowledge will be inappropriate. The author therefore uses a simple capillary bundle model with exemplary pressures, temperatures and permeabilities in order to assess the contribution of transport by diffusion. The diffusion coefficients, which are required for this and so far could not be measured under pressure, were determined by a new experimental method whose results will permit a better interpretation of the concentration dependence of the diffusion coefficient. The velocity of methane inflow and outflow in the water-filled pore space may provide knowledge on problems of gas storage in the pore space. (orig.) [Deutsch] Fuer den Foerderprozess und insbesondere seine Optimierung ist eine genaue Kenntnis der Transportmechanismen wesentlich. Unter den drastischen Bedingungen fuer Temperatur, Druck und Permeabilitaet tiefliegender Gas-Lagerstaetten mag die Uebertragung der bisherigen Vorstellungen ueber den Transport in der Lagerstaette zu einer unvollstaendigen Beschreibung fuehren. Unter Anwendung eines einfachen Kapillarbuendelmodells wird mit Beispielen fuer Druck, Temperatur und Permeabilitaet der moegliche Beitrag des Transports durch Diffusion abgeschaetzt. Zur Bestimmung der hierfuer notwendigen und bisher unter Druckbeaufschlagung nicht gemessenen Diffusionskoeffizienten wurde eine neue experimentelle Methode angewandt, deren Ergebnisse eine weiterfuehrende Interpretation der Konzentrationsabhaengigkeit des Diffusionskoeffizienten ermoeglichen. Auch fuer Fragestellungen der Speicherung von Gas im Porenraum kann die Geschwindigkeit der Ein- und Ausloesung von Methan im wasserhaltigen Porenraum von Interesse sein. (orig.)

  14. Synthesis and Gas Transport Properties of Hyperbranched Polyimide–Silica Hybrid/Composite Membranes

    Directory of Open Access Journals (Sweden)

    Masako Miki

    2013-12-01

    Full Text Available Hyperbranched polyimide–silica hybrids (HBPI–silica HBDs and hyperbranched polyimide–silica composites (HBPI–silica CPTs were prepared, and their general and gas transport properties were investigated to clarify the effect of silica sources and preparation methods. HBPI–silica HBDs and HBPI–silica CPTs were synthesized by two-step polymerization of A2 + B3 monomer system via polyamic acid as precursor, followed by hybridizing or blending silica sources. Silica components were incorporated by the sol-gel reaction with tetramethoxysilane (TMOS or the addition of colloidal silica. In HBPI-silica HBDs, the aggregation of silica components is controlled because of the high affinity of HBPI and silica caused by the formation of covalent bonds between HBPI and silica. Consequently, HBPI-silica HBDs had good film formability, transparency, and mechanical properties compared with HBPI-silica CPTs. HBPI-silica HBD and CPT membranes prepared via the sol-gel reaction with TMOS showed specific gas permeabilities and permselectivities for CO2/CH4 separation, that is, both CO2 permeability and CO2/CH4 selectivity increased with increasing silica content. This result suggests that gas transport can occur through a molecular sieving effect of the porous silica network derived from the sol-gel reaction and/or through the narrow interfacial region between the silica networks and the organic matrix.

  15. Calculation models for prediction of Liquefied Natural Gas (LNG) ageing during ship transportation

    Energy Technology Data Exchange (ETDEWEB)

    Miana, Mario; Hoyo, Rafael del; Rodrigalvarez, Vega; Valdes, Jose Ramon [Instituto Tecnologico de Aragon, Area de Investigacion, Desarrollo y Servicios Tecnologicos, Maria de Luna 7, 50018 Zaragoza (Spain); Llorens, Raul [ENAGAS SA, Direccion de Ingenieria y Tecnologia del Gas, Autovia A - 2, km. 306.4, 50012 Zaragoza (Spain)

    2010-05-15

    A group of European gas transportation companies within the European Gas Research Group launched in 2007 the 'MOLAS' Project to provide a software program for the analysis of the Liquefied Natural Gas (LNG) ageing process during ship transportation. This program contains two different modeling approaches: a physical algorithm and an 'intelligent' model. Both models are fed with the same input data, which is composed of the ship characteristics (BOR and capacity), voyage duration, LNG composition, temperature, pressure, and volume occupied by liquid phase at the port of origin, together with pressure at the port of destination. The results obtained are the LNG composition, temperature and liquid volume at the port of destination. Furthermore, the physical model obtains the evolution over time of such variables en route as it is based on unsteady mass balances over the system, while the i-model applies neural networks to obtain regression coefficients from historical data composed only of origin and destination measurements. This paper describes both models and validates them from previous published models and experimental data measured in ENAGAS LNG regasification plants. (author)

  16. Radon as a natural tracer for gas transport within uranium waste rock piles

    International Nuclear Information System (INIS)

    Silva, N.C.; Chagas, E.G.L.; Dias, D.C.S.; Guerreiro, E.T.Z.; Alberti, H.L.C.; Braz, M.L.; Abreu, C.B.; Lopez, D.; Branco, O.; Fleming, P.

    2014-01-01

    Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Industrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222 Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222 Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m -3 with mean concentration of 320.7±263.3 kBq m -3 . (authors)

  17. Facilitated transport ceramic membranes for high-temperature gas cleanup. Final report, February 1990--April 1994

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, R.; Minford, E.; Damle, A.S.; Gangwal, S.K.; Hart, B.A.

    1994-04-01

    The objective of this program was to demonstrate the feasibility of developing high temperature, high pressure, facilitated transport ceramic membranes to control gaseous contaminants in Integrated Gasification Combined Cycle (IGCC) power generation systems. Meeting this objective requires that the contaminant gas H{sub 2}S be removed from an IGCC gas mixture without a substantial loss of the other gaseous components, specifically H{sub 2} and CH{sub 4}. As described above this requires consideration of other, nonconventional types of membranes. The solution evaluated in this program involved the use of facilitated transport membranes consisting of molten mixtures of alkali and alkaline earth carbonate salts immobilized in a microporous ceramic support. To accomplish this objective, Air Products and Chemicals, Inc., Golden Technologies Company Inc., and Research Triangle Institute worked together to develop and test high temperature facilitated membranes for the removal of H{sub 2}S from IGCC gas mixtures. Three basic experimental activities were pursued: (1) evaluation of the H{sub 2}S chemistry of a variety of alkali and alkaline earth carbonate salt mixtures; (2) development of microporous ceramic materials which were chemically and physically compatible with molten carbonate salt mixtures under IGCC conditions and which could function as a host to support a molten carbonate mixture and; (3) fabrication of molten carbonate/ceramic immobilized liquid membranes and evaluation of these membranes under conditions approximating those found in the intended application. Results of these activities are presented.

  18. Analysis of CO2 Separation from Flue Gas, Pipeline Transportation, and Sequestration in Coal

    Energy Technology Data Exchange (ETDEWEB)

    Eric P. Robertson

    2007-09-01

    This report was written to satisfy a milestone of the Enhanced Coal Bed Methane Recovery and CO2 Sequestration task of the Big Sky Carbon Sequestration project. The report begins to assess the costs associated with separating the CO2 from flue gas and then injecting it into an unminable coal seam. The technical challenges and costs associated with CO2 separation from flue gas and transportation of the separated CO2 from the point source to an appropriate sequestration target was analyzed. The report includes the selection of a specific coal-fired power plant for the application of CO2 separation technology. An appropriate CO2 separation technology was identified from existing commercial technologies. The report also includes a process design for the chosen technology tailored to the selected power plant that used to obtain accurate costs of separating the CO2 from the flue gas. In addition, an analysis of the costs for compression and transportation of the CO2 from the point-source to an appropriate coal bed sequestration site was included in the report.

  19. Modelling the gas transport and chemical processes related to clad oxidation and hydriding

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, R O; Rashid, Y R [ANATECH Research Corp., San Diego, CA (United States)

    1997-08-01

    Models are developed for the gas transport and chemical processes associated with the ingress of steam into a LWR fuel rod through a small defect. These models are used to determine the cladding regions in a defective fuel rod which are susceptible to massive hydriding and the creation of sunburst hydrides. The brittle nature of zirconium hydrides (ZrH{sub 2}) in these susceptible regions produces weak spots in the cladding which can act as initiation sites for cladding cracks under certain cladding stress conditions caused by fuel cladding mechanical interaction. The modeling of the axial gas transport is based on gaseous bimolar diffusion coupled with convective mass transport using the mass continuity equation. Hydrogen production is considered from steam reaction with cladding inner surface, fission products and internal components. Eventually, the production of hydrogen and its diffusion along the length results in high hydrogen concentration in locations remote from the primary defect. Under these conditions, the hydrogen can attack the cladding inner surface and breakdown the protective ZrO{sub 2} layer locally, initiating massive localized hydriding leading to sunburst hydride. The developed hydrogen evolution model is combined with a general purpose fuel behavior program to integrate the effects of power and burnup into the hydriding kinetics. Only in this manner can the behavior of a defected fuel rod be modeled to determine the conditions the result in fuel rod degradation. (author). 14 refs, 6 figs.

  20. CASCADER: An M-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Emer, D.F.; Shott, G.J.; Donahue, M.E.

    1993-02-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and diffusion. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. CASCADER is a gas-phase, one-space dimensional transport and fate model for M-chain radionuclides in very dry homogeneous or heterogeneous soil. This model contains barometric pressure-induced advection and diffusion together with linear irreversible and linear reversible sorption for each radionuclide. The advection velocity is derived from an embedded air-pumping submodel. The air-pumping submodel is based on an assumption of isothermal conditions, which is driven by barometric pressure. CASCADER allows the concentration of source radionuclides to decay via the classical Bateman chain of simple, first-order kinetic processes. The transported radionuclides also decay via first-order processes while in the soil. A mass conserving, flux-type inlet and exit set of boundary conditions are used. The user must supply the initial distribution for the parent radionuclide in the soil. The initial daughter distribution is found using equilibrium rules. The model is user friendly as it uses a prompt-driven, free-form input. The code is ANSI standard Fortran 77

  1. CASCADER: An m-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Emer, D.F.; Shott, G.J.; Donahue, M.E.

    1992-06-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes as they are advected and/or dispersed. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. CASCADER is a gas-phase, one space dimensional transport and fate model for an m-chain of radionuclides in very dry soil. This model contains barometric pressure-induced advection and diffusion together with linear irreversible and linear reversible sorption for each radionuclide. The advocation velocity is derived from an embedded air-pumping submodel. The airpumping submodel is based on an assumption of isothermal conditions and is barometric pressure driven. CASCADER allows the concentration of source radionuclides to decay via the classical Bateman chain of simple, first-order kinetic processes. The transported radionuclides also decay via first-order processes while in the soil. A mass conserving, flux-type inlet and exit set of boundary conditions is used. The user must supply the initial distribution for the parent radionuclide in the soil. The initial daughter distribution is found using equilibrium rules. The model is user friendly as it uses a prompt-driven, free-form input. The code is ANSI standard Fortran 77

  2. ALMACAL - III. A combined ALMA and MUSE survey for neutral, molecular, and ionized gas in an H I-absorption-selected system

    Science.gov (United States)

    Klitsch, A.; Péroux, C.; Zwaan, M. A.; Smail, I.; Oteo, I.; Biggs, A. D.; Popping, G.; Swinbank, A. M.

    2018-03-01

    Studying the flow of baryons into and out of galaxies is an important part of understanding the evolution of galaxies over time. We present a detailed case study of the environment around an intervening Ly α absorption line system at zabs = 0.633, seen towards the quasar J0423-0130 (zQSO = 0.915). We detect with ALMA the 12CO(2-1), 12CO(3-2), and 1.2 mm continuum emission from a galaxy at the redshift of the Ly α absorber at a projected distance of 135 kpc. From the ALMA detections, we infer interstellar medium conditions similar to those in low-redshift luminous infrared galaxies. Director's Discretionary Time (DDT) Multi-Unit Spectroscopic Explorer (MUSE) integral field unit observations reveal the optical counterpart of the 12CO emission line source and three additional emission line galaxies at the absorber redshift, which together form a galaxy group. The 12CO emission line detections originate from the most massive galaxy in this group. While we cannot exclude that we miss a fainter host, we reach a dust-uncorrected star formation rate (SFR) limit of >0.3 M⊙yr-1 within 100 kpc from the sightline to the background quasar. We measure the dust-corrected SFR (ranging from 3 to 50 M⊙ yr-1), the morpho-kinematics and the metallicities of the four group galaxies to understand the relation between the group and the neutral gas probed in absorption. We find that the Ly α absorber traces either an outflow from the most massive galaxy or intragroup gas. This case study illustrates the power of combining ALMA and MUSE to obtain a census of the cool baryons in a bounded structure at intermediate redshift.

  3. Gas-fuelled driving and sailing. Cost and environmental effects of natural gas and green gas in transport; Rijden en varen op gas. Kosten en milieueffecten van aardgas en groen gas in transport

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, B.E.; Croezen, H.J.; Verbraak, G.M.; Brouwer, F.P.E.

    2010-06-15

    A number of new gaseous fuels for cars and ships is becoming more popular: compressed natural gas (CNG), liquid natural gas (LNG) and biogas. This report presents the results of a study of the costs and environmental effects of these gas applications and compares them to diesel and petrol and the 'common' biofuels biodiesel and bio-ethanol. The green gas applications emit much less CO2 than biodiesel and bio-ethanol from wheat. The air-polluting emissions are much lower in all cases. The basic cost of driving or sailing on these gaseous fuels (excl. levies and taxes) are significantly higher than in case of diesel, but in some cases van be comparable or even lower than in case of liquid biofuels. [Dutch] Een aantal nieuwe gasvormige brandstoffen voor auto's en schepen is in opkomst: aardgas onder druk (CNG), vloeibaar aardgas (LNG) en biogassen. In dit rapport worden de resultaten van een onderzoek naar de kosten en de milieueffecten van deze gastoepassingen gepresenteerd en vergeleken met diesel en benzine en de 'gewone' biobrandstoffen bio-diesel en bio-ethanol. De groen gas-toepassingen stoten aanzienlijk minder CO2 uit dan biodiesel en bio-ethanol uit tarwe. De luchtvervuilende emissies zijn in alle gevallen een stuk lager. De kale kosten van rijden en varen op deze gasvormige brandstoffen (excl. heffingen en belastingen) zijn wel aanzienlijk hoger dan bij diesel, maar kunnen in sommige toepassingen vergelijkbaar of lager uitkomen dan van de vloeibare biobrandstoffen.

  4. Price cap regulation: the case of natural gas transport in the UK; La reglementation par price cap: le cas du transport de gaz naturel au Royaume Uni

    Energy Technology Data Exchange (ETDEWEB)

    David, L. [ATER, Paris-1 Univ., 75 (France)

    1999-09-01

    The transport and storage activities of British Gas company are controlled by a distinct organization named Transco. The access charges paid by the suppliers for the use of Transco's network are regulated by a price cap since October 1, 1994. However, Ofgas, the office of gas supply which is the regulation authority in charge of the control of competition and of British Gas activities, considers this control system as inefficient and has chosen a RPI (retail price index)-X (expected productivity factor)-type price cap for the control of gas transport tariffs. This has led to a disagreement between Transco and Ofgas which has delayed the implementation of the new system up to February 1998. This article compares the choices made by Ofgas for the control of gas transport tariffs with the economical theory. It recalls first, the reasons why the price cap appears as more efficient than the service cost regulation, the alternate method used by regulation authorities to control the tariffs of natural monopolies. Then, the difficulties linked with the implementation of the price cap for the transport of natural gas in the UK are analyzed in order to explain the reasons that led Ofgas to change its formula. Finally, the bases of an optimum hybrid formula are proposed. (J.S.)

  5. FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres

    Science.gov (United States)

    Stock, Joachim W.; Kitzmann, Daniel; Patzer, A. Beate C.; Sedlmayr, Erwin

    2018-06-01

    For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied method is based on the solution of a system of coupled nonlinear (and linear) algebraic equations, namely the law of mass action and the element conservation equations including charge balance, in many variables. Specifically, the system of equations is decomposed into a set of coupled nonlinear equations in one variable each, which are solved analytically whenever feasible to reduce computation time. Notably, the electron density is determined by using the method of Nelder and Mead at low temperatures. The program is written in object-oriented C++ which makes it easy to couple the code with other programs, although a stand-alone version is provided. FastChem can be used in parallel or sequentially and is available under the GNU General Public License version 3 at https://github.com/exoclime/FastChem together with several sample applications. The code has been successfully validated against previous studies and its convergence behavior has been tested even for extreme physical parameter ranges down to 100 K and up to 1000 bar. FastChem converges stable and robust in even most demanding chemical situations, which posed sometimes extreme challenges for previous algorithms.

  6. Earthquake loss estimation for a gas lifeline transportation system in Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Yamin, L.E.; Arambula, S.; Reyes, J.C. [Universidad de los Andes, Bogota (Colombia). Centro de Innovacion y Desarrollo Tecnologico; Belage, S.; Vega, A.; Gil, W. [TransGas de Occidente S.A., Bogota (Colombia)

    2004-07-01

    Methodologies are needed to estimate the seismic risk facing natural gas distribution systems in Colombia in order to establish insurance strategies, risk assessments and emergency plans. This study estimated the maximum probable losses associated with Colombia's 770 km long gas transportation system which stretches from Mariquita to Cali. The pipeline is vulnerable to seismic events, volcanic eruptions, extreme hydrological conditions, and their associated effects such as landslides, liquefaction and avalanches. A geographic information system (GIS) which includes seismic, volcanic, landslide and liquefaction hazards was used to estimate earthquake loss estimates for the natural gas distribution system. Elastic and inelastic finite element methods were used to evaluate the vulnerability of pipelines, bridges, underground crossings and valves. The results were incorporated into the GIS and were used to quantify the probable maximum losses for the system, the most critical associated event, the system's critical zones and the probable damage scenarios. The information was used to define insurance strategies, emergency and contingency plans. It was concluded that due to natural hazards, the natural gas distribution system is at moderate risk despite the low vulnerability of its components. Volcanic eruptions and large earthquakes could produce indirect phenomena such as landslides and liquefaction which could greatly influence the system and which would require adequate risk management. 14 refs., 1 tab., 8 figs.

  7. A case study of electrostatic accidents in the process of oil-gas storage and transportation

    International Nuclear Information System (INIS)

    Hu, Yuqin; Liu, Jinyu; Gao, Jianshen; Wang, Diansheng

    2013-01-01

    Ninety nine electrostatic accidents were reviewed, based on information collected from published literature. All the accidents over the last 30 years occurred during the process of oil-gas storage and transportation. Statistical analysis of these accidents was performed based on the type of complex conditions where accidents occurred, type of tanks and contents, and type of accidents. It is shown that about 85% of the accidents occurred in tank farms, gas stations or petroleum refineries, and 96% of the accidents included fire or explosion. The fishbone diagram was used to summarize the effects and the causes of the effects. The results show that three major reasons were responsible for accidents, including improper operation during loading and unloading oil, poor grounding and static electricity on human bodies, which accounted for 29%, 24% and 13% of the accidents, respectively. Safety actions are suggested to help operating engineers to handle similar situations in the future.

  8. An Experimental and Finite Element Protocol to Investigate the Transport of Neutral and Charged Solutes across Articular Cartilage.

    Science.gov (United States)

    Arbabi, Vahid; Pouran, Behdad; Zadpoor, Amir A; Weinans, Harrie

    2017-04-23

    Osteoarthritis (OA) is a debilitating disease that is associated with degeneration of articular cartilage and subchondral bone. Degeneration of articular cartilage impairs its load-bearing function substantially as it experiences tremendous chemical degradation, i.e. proteoglycan loss and collagen fibril disruption. One promising way to investigate chemical damage mechanisms during OA is to expose the cartilage specimens to an external solute and monitor the diffusion of the molecules. The degree of cartilage damage (i.e. concentration and configuration of essential macromolecules) is associated with collisional energy loss of external solutes while moving across articular cartilage creates different diffusion characteristics compared to healthy cartilage. In this study, we introduce a protocol, which consists of several steps and is based on previously developed experimental micro-Computed Tomography (micro-CT) and finite element modeling. The transport of charged and uncharged iodinated molecules is first recorded using micro-CT, which is followed by applying biphasic-solute and multiphasic finite element models to obtain diffusion coefficients and fixed charge densities across cartilage zones.

  9. The use of the dusty-gas model for the description of mass transport with chemical reaction in porous media

    NARCIS (Netherlands)

    Veldsink, J.W.; Veldsink, J.W.; van Damme, Rudolf M.J.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria

    1995-01-01

    In the present study, mass transport accompanied by chemical reactions in porous media is studied according to the Fick model and the dusty-gas model. For mass transport accompanied by a chemical reaction in catalyst structures showing a plane, line, or point of symmetry, the approximate analytical

  10. Evaluation of alternatives for reducing the consumption of natural gas fuel at city-gates of Brazilian transport systems; Avaliacao das alternativas de reducao do consumo de gas natural combustivel nos pontos de entrega dos sistemas de transporte brasileiros

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Almir B [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil); Augusto, Cristiane R; Seidl, Peter R [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica; Goncalves, Raquel G [UNISUAM - Centro Universitario Augusto Motta, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This work aims to identify actions that can be implemented to increase the energy efficiency of processes involved in the value chain of natural gas, specifically in the process of heating in existing city-gates of transporting natural gas Brazilians plants. The goal is increase supply of gas in Brazil. The main function of city-gates is to deliver the natural gas in contract terms (flow, pressure, temperature and quality). The main issue related to the consumption of natural gas fuel in city-gates is related to the operation (set-up and control) of natural gas combustion, in other words, depends on how the heating system is adjusted dynamically to burn, efficiently, the exact amount of gas required by this system, depending on temperature, pressure, temperature, quality and flow of natural gas at the 'city-gates'. The main objective of this work is to present a study on alternatives at design, set-up and control of natural gas city-gates (transport) in Brazil, aiming to increase the energy efficiency of this facility, and thus contributing to the growth in supply of natural gas available to the market. (author)

  11. Evaluation of alternatives for reducing the consumption of natural gas fuel at city-gates of Brazilian transport systems; Avaliacao das alternativas de reducao do consumo de gas natural combustivel nos pontos de entrega dos sistemas de transporte brasileiros

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Almir B. [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil); Augusto, Cristiane R.; Seidl, Peter R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica; Goncalves, Raquel G. [UNISUAM - Centro Universitario Augusto Motta, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This work aims to identify actions that can be implemented to increase the energy efficiency of processes involved in the value chain of natural gas, specifically in the process of heating in existing city-gates of transporting natural gas Brazilians plants. The goal is increase supply of gas in Brazil. The main function of city-gates is to deliver the natural gas in contract terms (flow, pressure, temperature and quality). The main issue related to the consumption of natural gas fuel in city-gates is related to the operation (set-up and control) of natural gas combustion, in other words, depends on how the heating system is adjusted dynamically to burn, efficiently, the exact amount of gas required by this system, depending on temperature, pressure, temperature, quality and flow of natural gas at the 'city-gates'. The main objective of this work is to present a study on alternatives at design, set-up and control of natural gas city-gates (transport) in Brazil, aiming to increase the energy efficiency of this facility, and thus contributing to the growth in supply of natural gas available to the market. (author)

  12. Scenarios of high greenhouse gas emission reduction in transports and buildings by 2050

    International Nuclear Information System (INIS)

    Teissier, O.; Meunier, L.

    2008-01-01

    The authors report simulations of different environmental policy measures concerning transports and buildings in France. First, they review measures which may entail a reduction of greenhouse gas emissions, and comment their emission reduction potential and their implementation costs. These measures are then ranked, and only those presenting a significant potential and an economically and technologically feasibility are finally considered. Their impact is then simulated by using different models which are adapted to the both sectors and to time ranges. The obtained results are compared to those obtained with a calibrated trend scenario and with a 'factor 4' scenario

  13. Focal spot size predictions for beam transport through a gas-filled reactor

    International Nuclear Information System (INIS)

    Yu, S.S.; Lee, E.P.; Buchanan, H.L.

    1980-01-01

    Results from calculations of focal spot size for beam transport through a gas-filled reactor are summarized. In the converging beam mode, we find an enlargement of the focal spot due to multiple scattering and zeroth order self-field effects. This enlargement can be minimized by maintaining small reactors together with a careful choice of the gaseous medium. The self-focused mode, on the other hand, is relatively insensitive to the reactor environment, but is critically dependent upon initial beam quality. This requirement on beam quality can be significantly eased by the injection of an electron beam of modest current from the opposite wall

  14. Sensitivity analysis of the noble gas transport and fate model: CASCADR9

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Barker, L.E.

    1994-03-01

    CASCADR9 is a desert alluvial soil site-specific noble gas transport and fate model. Input parameters for CASCADR9 are: man-made source term, background concentration of radionuclides, radon half-life, soil porosity, period of barometric pressure wave, amplitude of barometric pressure wave, and effective eddy diffusivity. Using average flux, total flow, and radon concentration at the 40 day mark as output parameters, a sensitivity analysis for CASCADR9 is carried out, under a variety of scenarios. For each scenario, the parameter to which output parameters are most sensitive are identified

  15. Prediction of Repair Work Duration for Gas Transport Systems Based on Small Data Samples

    DEFF Research Database (Denmark)

    Lesnykh, Valery; Litvin, Yuri; Kozin, Igor

    2016-01-01

    Prediction of the duration of a repair and maintenance project of a gas transport system is an important part of planning activities. There exist numerous sources of uncertainties that may result in time overruns possibly leading to multiple negative consequences. Our experience in planning...... this work suggests that accepting the stochastic nature of the project duration is a constructive step towards the preparedness to contingencies and defining penalties for repair companies. To support this approach, one needs to construct probability distributions of the durations of the projects...

  16. Advective and diffusive contributions to reactive gas transport during pyrite oxidation in the unsaturated zone

    DEFF Research Database (Denmark)

    Binning, Philip John; Postma, Diederik Jan; Russel, T.F.

    2007-01-01

    Pyrite oxidation in unsaturated mine waste rock dumps and soils is limited by the supply of oxygen from the atmosphere. In models, oxygen transport through the subsurface is often assumed to be driven by diffusion. However, oxygen comprises 23.2% by mass of dry air, and when oxygen is consumed at...... parameters; for example, the time to approach steady state depends exponentially on the distance between the soil surface and the subsurface reactive zone. Copyright 2007 by the American Geophysical Union....... at depth in the unsaturated zone, a pressure gradient is created between the reactive zone and the ground surface, causing a substantial advective air flow into the subsurface. To determine the balance between advective and diffusive transport, a one-dimensional multicomponent unsaturated zone gas...

  17. Corn Ethanol: The Surprisingly Effective Route for Natural Gas Consumption in the Transportation Sector

    Energy Technology Data Exchange (ETDEWEB)

    Szybist, James P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Curran, Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-05-01

    Proven reserves and production of natural gas (NG) in the United States have increased dramatically in the last decade, due largely to the commercialization of hydraulic fracturing. This has led to a plentiful supply of NG, resulting in a significantly lower cost on a gallon of gasoline-equivalent (GGE) basis. Additionally, NG is a domestic, non-petroleum source of energy that is less carbon-intensive than coal or petroleum products, and thus can lead to lower greenhouse gas emissions. Because of these factors, there is a desire to increase the use of NG in the transportation sector in the United States (U.S.). However, using NG directly in the transportation sector requires that several non-trivial challenges be overcome. One of these issues is the fueling infrastructure. There are currently only 1,375 NG fueling stations in the U.S. compared to 152,995 fueling stations for gasoline in 2014. Additionally, there are very few light-duty vehicles that can consume this fuel directly as dedicated or bi-fuel options. For example, in model year 2013Honda was the only OEM to offer a dedicated CNG sedan while a number of others offered CNG options as a preparation package for LD trucks and vans. In total, there were a total of 11 vehicle models in 2013 that could be purchased that could use natural gas directly. There are additional potential issues associated with NG vehicles as well. Compared to commercial refueling stations, the at-home refueling time for NG vehicles is substantial – a result of the small compressors used for home refilling. Additionally, the methane emissions from both refueling (leakage) and from tailpipe emissions (slip) from these vehicles can add to their GHG footprint, and while these emissions are not currently regulated it could be a barrier in the future, especially in scenarios with broad scale adoption of CNG vehicles. However, NG consumption already plays a large role in other sectors of the economy, including some that are important to

  18. Contribution to internal pressure and flammable gas concentration in RAM [radioactive material] transport packages

    International Nuclear Information System (INIS)

    Warrant, M.M.; Brown, N.

    1989-01-01

    Various facilities in the US generate wastes contaminated with transuranic (TRU) isotopes (such as plutonium and americium) that decay primarily by emission of alpha particles. The waste materials consist of a wide variety of commercially available plastics, paper, cloth, and rubber; concreted or sludge wastes containing water; and metals, glass, and other solid inorganic materials. TRU wastes that have surface dose rates of 200 mrem/hr or less are typically packaged in plastic bags placed inside metal drums or boxes that are vented through high efficiency particulate air (HEPA) filters. These wastes are to be transported from waste generation or storage sites to the Waste Isolation Pilot Plant (WIPP) in the TRUPACT-II, a Type B package. Radiolysis of organic wastes or packaging materials, or wastes containing water generates gas which may be flammable or simply contribute to the internal pressure of the radioactive material (RAM) transport package. This paper discusses the factors that affect the amount and composition of this gas, and summarizes maximum radiolytic G values (number of molecules produced per 100 eV absorbed energy) found in the technical literature for many common materials. These G values can be used to determine the combination of payload materials and decay heats that are safe for transport. G values are established for categories of materials, based on chemical functional groups. It is also shown using transient diffusion and quasi-equilibrium statistical mechanics methods that hydrogen, if generated, will not stratify at the top of the transport package void space. 9 refs., 1 tab

  19. Legal and regulatory possibility of connection between interstate natural gas distribution networks instead of constructing transport pipelines; Possibilidade juridoco-regulatoria da conexao interestadual entre redes de distribuicao de gas natural como alternativa a construcao de gasodutos de transporte

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Gustavo Mano [Andrade, Mano - Advogados, Rio de Janeiro, RJ (Brazil)

    2012-07-01

    According to Revista Brasil Energia (2011a), the local natural gas distribution concessionaire in the State of Sao Paulo Gas Brasiliano Distribuidora - GBD, plans to expand its distribution pipeline network in western Sao Paulo up to the border of the State of Minas Gerais, near the region known as Minas Triangle where a connection with the pipeline network of the State of Minas Gerais' natural gas distribution company, Companhia de Gas de Minas Gerais - GASMIG shall be built in order to supply natural gas to an ammonia plant to be built by PETROBRAS in the City of Uberaba. Still according to the publication, the project described above would be an alternative to the construction of a transportation pipeline that, since the enforcement of the Gas Law - Law No. 11.909/09 (Brasil, 2009), should be subject to concession contracts preceded by a complex, and probably delayed, planning and procurement. However, there is a transportation pipeline project, deriving from the Bolivia-Brazil transportation pipeline near the city of Sao Carlos, in Sao Paulo, crossing the Minas Triangle and finishing in the State of Goias. This project is owned by TGBC Company. The existence of two gas pipeline projects with very similar paths to supply virtually the same regions and based on different regulatory frameworks, one consisting of a connection between the distribution networks of different States and another based on the concept of pipeline transportation of gas under the legal and regulatory federal jurisdiction raises the discussion about the possibility of legal and regulatory interstate connections of distribution pipeline networks as an alternative to planning, allocation and construction of a transportation pipelines. This article aims to examine the legal and regulatory foundations of both alternatives and delineate the limits of performance of States and Federal Government on legislation and regulation concerning the movement of natural gas pipeline through the Country

  20. Greenhouse gas emissions from Thailand’s transport sector: Trends and mitigation options

    International Nuclear Information System (INIS)

    Pongthanaisawan, Jakapong; Sorapipatana, Chumnong

    2013-01-01

    Rapid growth of population and economy during the past two decades has resulted in continuing growth of transport’s oil demand and greenhouse gas (GHG) emissions. The objectives of this study are to examine pattern and growth in energy demand as well as related GHG emissions from the transport sector and to analyze potential pathways of energy demand and GHG emissions reduction from this sector of the measures being set by the Thai Government. A set of econometric models has been developed to estimate the historical trend of energy demand and GHG emissions in the transport sector during 1989–2007 and to forecast future trends to 2030. Two mitigation option scenarios of fuel switching and energy efficiency options have been designed to analyze pathways of energy consumption and GHG emissions reduction potential in Thailand’s transport sector compared with the baseline business-as-usual (BAU) scenario, which assumed to do nothing influences the long-term trends of transport energy demand. It has been found that these two mitigation options can reduce the GHG emissions differently. The fuel-switching option could significantly reduce the amount of GHG emissions in a relatively short time frame, albeit it will be limited by its supply resources, whereas the energy efficiency option is more effective for GHG emissions mitigation in the long term. Therefore, both measures should be implemented simultaneously for both short and long term mitigation effects in order to more effectively achieve GHG emissions reduction target.

  1. Positrons in gas filled traps and their transport in molecular gases

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, Z Lj; Bankovic, A; Marjanovic, S; Suvakov, M; Dujko, S; Malovic, G [Institute of Physics, University of Belgrade, Pregrevica 118, POB 68, Zemun (Serbia); White, R D [ARC Centre for Antimatter-Matter Studies, James Cook University, Townsville 4810, QLD (Australia); Buckman, S J, E-mail: zoran@ipb.ac.rs [ARC Centre for Antimatter-Matter Studies, Australian National University, Canberra, ACT, 0200 (Australia)

    2011-01-01

    In this paper we give a review of two recent developments in positron transport, calculation of transport coefficients for a relatively complete set of collision cross sections for water vapour and for application of they Monte Carlo technique to model gas filled subexcitation positron traps such as Penning Malmberg Surko (Surko) trap. Calculated transport coefficients, very much like those for argon and other molecular gases show several new kinetic phenomena. The most important is the negative differential conductivity (NDC) for the bulk drift velocity when the flux drift velocity shows no sign of NDC. These results in water vapour are similar to the results in argon or hydrogen. The same technique that has been used for positron (and previously electron) transport may be applied to model development of particles in a Surko trap. We have provided calculation of the ensemble of positrons in the trap from an initial beam like distribution to the fully thermalised distribution. This model, however, does not include plasma effects (interaction between charged particles) and may be applied for lower positron densities.

  2. Risks in the transport and storage of liquefied natural gas. Sub-project 5-2: Investigation into building damage

    Science.gov (United States)

    Gouwens, C.; Dragosavic, M.

    The large reserves and increasing use of natural gas as a source of energy have resulted in its storage and transport becoming an urgent problem. Since a liquid of the same mass occupies only a fraction of the volume of a gas, it is economical to store natural gas as a liquid. Liquefied natural gas is stored in insulated tanks and also carried by ship at a temperature of -160 C to 170 C. If a serious accident allows the LNG to escape, a gas cloud forms. The results of a possible explosion from such a gas cloud are studied. The development of a leak, escape and evaporation, size and propagation of the gas cloud, the explosive pressures to be expected and the results on the environment are investigated. Damage to buildings is examined making use of the preliminary conclusions of the other sub-projects and especially the explosive pressures.

  3. Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

    International Nuclear Information System (INIS)

    Marschall, P.; Horseman, S.; Gimmi, T.

    2005-01-01

    The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

  4. Integral diagnostic in the failure causes of external corrosion of a natural gas transport pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Mendoza, J.L.; Saucedo-Robles, L.C.; Rodriguez-Clemente, H. [PEMEX Gas y Petroquimica Basica, Subdireccion de Ductos; Marina Nacional 329, Edificio B-1, Piso 8, Col. Huasteca, D.F., CP 11311 (Mexico); Gonzalez-Nunez, M.A. [Instituto de Investigaciones Electricas, Reforma 113, Col. Palmira, Cuernavaca, Morelos, CP 62490 (Mexico); Zavala-Olivares, G.; Hernandez-Gayosso, M.J. [Instituto Mexicano del Petroleo, Direccion de Exploracion y Produccion, Eje Central Lazaro Cardenas Norte 152, Col. San Bartolo Atepehuacan, D.F., CP 07730 (Mexico)

    2011-08-15

    The objective of this study consisted in investigating the possible causes which give rise to the presence of low wall pipe thicknesses on a 16'' natural gas transport pipeline, even though during the last 12-year period cathodic protection (CP) potentials were kept in the protection range at which external corrosion should not occur. Results from in-line inspection from a 16'' natural gas transport pipeline showed 46 indications with more than 80% wall thickness lost due to external corrosion in the second segment of the pipeline. Direct inspection at the indication locations, review of the CP system performance, pipeline maintenance programs and studies, allowed to make an integral diagnostic where it was found out that the main cause of external corrosion was an inappropriate coating application since the pipeline construction, this situation has originated the increase of CP shielding effects through time. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Large-scale application of natural gas as an engine fuel in public transport

    International Nuclear Information System (INIS)

    Verstegen, P.; Nieuwenhuis, A.; Van Schagen, G.J.

    1993-02-01

    Options and bottlenecks for the use of compressed natural gas (CNG) as an automotive fuel in public transportation have been inventorized and discussed. Based on interviews with representatives of transportation businesses and their umbrella organizations the demands and wishes are listed in chapter one. In chapter two several types of natural gas storage cylinders, focusing on the weight and the costs of the cylinders and the consequences for the road tax. In chapter three attention is paid to the delivery possibilities of the bus manufacturers DAF, Mercedes-Benz, Volvo and MAN. Technical specifications and data on the energy consumption, emission and other aspects are presented. In chapter three the characteristics of fastfill stations and slowfill stations are assessed for implementing problems, costs and reliability. The costs for the use of CNG in buses, as discussed in chapter five, consist of additional costs for the bus, maintenance, road tax, filling station, safety provisions, and reduced costs for the fuel. In chapter six the regulations and legislation for the use of CNG in vehicles, filling stations and storage cylinders is dealt with. In the final chapters seven and eight the necessity of introductory courses and training is briefly discussed, and an overview of current projects in the Netherlands is given. 13 figs., 14 tabs., refs

  6. Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport.

    Science.gov (United States)

    Sheng, Zhizhi; Wang, Honglong; Tang, Yongliang; Wang, Miao; Huang, Lizhi; Min, Lingli; Meng, Haiqiang; Chen, Songyue; Jiang, Lei; Hou, Xu

    2018-02-01

    The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gases and liquids under a steady-state applied pressure, nearly eliminate fouling, and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores' deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.

  7. Neutral currents

    International Nuclear Information System (INIS)

    Paschos, E.A.

    1977-01-01

    It is stated that over the past few years considerable progress has been made in the field of weak interactions. The existence of neutral currents involving leptons and hadrons has been established and some of the questions concerning their detailed structure have been answered. This imposes constraints on the gauge theories and has eliminated large classes of models. New questions have also been raised, one of which concerns the conservation laws obeyed by neutral currents. The wide range of investigations is impressive and is expected to continue with new results from particle, nuclear, and atomic physics. Headings include - various aspects of a gauge theory (choice of group, the symmetry breaking scheme, representation assignments for fermion fields); space-time structure; isospin structure; leptonic neutral currents; and atomic experiments. (U.K.)

  8. Report of the experts group on the taxation of the access to gas transport and distribution network; Rapport du groupe d'experts sur la tarification de l'acces aux reseaux de transport et de distribution de gaz

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-04-01

    In the framework of a new french gas industry organization (directive of the 22 june 1998), a concerting mission has been realized on prices taxation for the transport and distribution facilities. The following topics have been debated: the integration and competition of the european gas market, the gas market liberalization consistency and the taxation of transport and distribution network access. (A.L.B.)

  9. Neutral currents

    International Nuclear Information System (INIS)

    Aubert, B.

    1994-11-01

    The evidence for the existence of weak neutral current has been a very controverted topics in the early 1970's, as well as the muon did in the 1930's. The history is very rich considering the evolution of the experimental techniques in high energy particle physics. The history of the discovery and the study of weak neutral current is reviewed. Later the quest of the intermediate vector boson continues with the decision of the community to build a large proton antiproton collider. (K.A.). 14 refs., 1 fig

  10. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    Science.gov (United States)

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Mathematical modelling of water and gas transport in layered soil covers for coal ash deposits

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, A; Lindgren, M [Kemakta Consultants Co, Stockholm (SE)

    1990-12-17

    In the present work the dry deposition alternative is investigated. In particular the design of soil covers is treated theoretically using mathematical models. The soil cover should primarily act as a barrier against infiltrating water. This is done by having soil cover materials with low permeabilities and sloping covers thereby diverting the infiltrating water in the lateral direction. An important design aspect is that overflow should be avoided since this may cause erosional problems. Thus the design of the cover should allow for lateral water flow within the cover. In the present work we use the computer code TRUST for calculating the flow rates and the moisture contents in two layer covers (till on top of clay) for varying conditions. The calculations so far show that the hydraulic conductivity of the clay layer should be smaller than 10{sup -8} m/s. However, for the simulated longer covers (50 m) a lower hydraulic conductivity gives overflow indicating that better lateral drainage must be provided for. This can be done by increasing the thickness or hydraulic conductivity of the till layer. Simulations for different slopes give little impact, while the hydraulic conductivity of the clay layer is of major importance. Gas transport through the soil cover may be of importance if the waste contains pyrite. In the presence of oxygen and water, pyrite is oxidized producing sulphuric acid. The lowered pH will accelerate the leaching of several heavy metals. The transport rate of gas through a porous material is very sensitive to the water content, decreasing rapidly with increasing water content. In the present work a model, where the unsaturated conditions are accounted for, is outlined. A previously developed method for calculating oxygen transport and oxidation rate of pyrite in connection with mine wastes is generalized from 1D to 2D. A sample calculation illustrates the feasibility of the method. (au) (43 refs.).

  12. Improving the accuracy of vehicle emissions profiles for urban transportation greenhouse gas and air pollution inventories.

    Science.gov (United States)

    Reyna, Janet L; Chester, Mikhail V; Ahn, Soyoung; Fraser, Andrew M

    2015-01-06

    Metropolitan greenhouse gas and air emissions inventories can better account for the variability in vehicle movement, fleet composition, and infrastructure that exists within and between regions, to develop more accurate information for environmental goals. With emerging access to high quality data, new methods are needed for informing transportation emissions assessment practitioners of the relevant vehicle and infrastructure characteristics that should be prioritized in modeling to improve the accuracy of inventories. The sensitivity of light and heavy-duty vehicle greenhouse gas (GHG) and conventional air pollutant (CAP) emissions to speed, weight, age, and roadway gradient are examined with second-by-second velocity profiles on freeway and arterial roads under free-flow and congestion scenarios. By creating upper and lower bounds for each factor, the potential variability which could exist in transportation emissions assessments is estimated. When comparing the effects of changes in these characteristics across U.S. cities against average characteristics of the U.S. fleet and infrastructure, significant variability in emissions is found to exist. GHGs from light-duty vehicles could vary by -2%-11% and CAP by -47%-228% when compared to the baseline. For heavy-duty vehicles, the variability is -21%-55% and -32%-174%, respectively. The results show that cities should more aggressively pursue the integration of emerging big data into regional transportation emissions modeling, and the integration of these data is likely to impact GHG and CAP inventories and how aggressively policies should be implemented to meet reductions. A web-tool is developed to aide cities in improving emissions uncertainty.

  13. Operational Challenges in Gas-To-Liquid (GTL) Transportation Through Trans Alaska Pipeline System (TAPS)

    Energy Technology Data Exchange (ETDEWEB)

    Godwin A. Chukwu; Santanu Khataniar; Shirish Patil; Abhijit Dandekar

    2006-06-30

    Oil production from Alaskan North Slope oil fields has steadily declined. In the near future, ANS crude oil production will decline to such a level (200,000 to 400,000 bbl/day) that maintaining economic operation of the Trans-Alaska Pipeline System (TAPS) will require pumping alternative products through the system. Heavy oil deposits in the West Sak and Ugnu formations are a potential resource, although transporting these products involves addressing important sedimentation issues. One possibility is the use of Gas-to-Liquid (GTL) technology. Estimated recoverable gas reserves of 38 trillion cubic feet (TCF) on the North Slope of Alaska can be converted to liquid with GTL technology and combined with the heavy oils for a product suitable for pipeline transport. Issues that could affect transport of this such products through TAPS include pumpability of GTL and crude oil blends, cold restart of the pipeline following a prolonged winter shutdown, and solids deposition inside the pipeline. This study examined several key fluid properties of GTL, crude oil and four selected blends under TAPS operating conditions. Key measurements included Reid Vapor Pressure, density and viscosity, PVT properties, and solids deposition. Results showed that gel strength is not a significant factor for the ratios of GTL-crude oil blend mixtures (1:1; 1:2; 1:3; 1:4) tested under TAPS cold re-start conditions at temperatures above - 20 F, although Bingham fluid flow characteristics exhibited by the blends at low temperatures indicate high pumping power requirements following prolonged shutdown. Solids deposition is a major concern for all studied blends. For the commingled flow profile studied, decreased throughput can result in increased and more rapid solid deposition along the pipe wall, resulting in more frequent pigging of the pipeline or, if left unchecked, pipeline corrosion.

  14. Water transport in gas diffusion media for PEM fuel cells. Experimental and numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Joerg

    2010-08-20

    The water flux in partially saturated hydrophobic carbon fibre paper for polymer electrolyte membrane fuel cell applications is investigated and compared with the frequently used constitutive two-phase flow model based on Darcy's law. Further, the first steps towards a math-based material design for gas diffusion media are explored in this thesis. Two self-developed ex-situ experiments to investigate the liquid water transport are introduced. The first is a newly developed buoyancy-based measurement of the pressuresaturation relationship on thin porous material with an accuracy of 0.5 kPa for the pressure and {+-} 5% for the saturation. The second experiment measures the pressure drop in dependence of flow rates down to magnitudes of {mu}L/s across the partially saturated thin porous material. This flow rate is relevant for the fuel cell application. The liquid water transport through Toray 060 carbon fibre paper, impregnated with 7% and 10% PTFE is investigated at wet and dry boundary conditions. The experiments are also accompanied by analytical and numerical free surface modelling with the consideration of the material morphology and liquid-solid interaction. The imbibing and draining cases of an arrangement of six fibres at varying solid-liquid interaction and boundary conditions are studied with 'Surface Evolver'. In order to evaluate the findings of ex-situ and modelling work for applicability to water transport in fuel cell operation, the technique of nuclear magnetic resonance (NMR) imaging is assessed. The focus is on the visualisation of 2D and 3D water distribution in the operating fuel cell. The compatibility of the NMR experiment with fuel cell operation in relation to material selection, operating temperature, and current density is addressed. NMR imaging is employed for different current densities, stoichiometries, and fuel cell arrangements. The fuel cell arrangements differ by the cathode diffusion medium. Plain, hydrophobic, and

  15. Ammonia gas transport and reactions in unsaturated sediments: Implications for use as an amendment to immobilize inorganic contaminants

    International Nuclear Information System (INIS)

    Zhong, L.; Szecsody, J.E.; Truex, M.J.; Williams, M.D.; Liu, Y.

    2015-01-01

    Highlights: • Ammonia transport can be predicted from gas movement and equilibrium partitioning. • Ammonia diffusion rate in unsaturated sediment is a function of water contents. • High pH induced by ammonia causes mineral dissolution and sequential precipitation. • Ammonia treatment effectively immobilized uranium from contaminated sediments. - Abstract: Use of gas-phase amendments for in situ remediation of inorganic contaminants in unsaturated sediments of the vadose zone may be advantageous, but there has been limited development and testing of gas remediation technologies. Treatment with ammonia gas has a potential for use in treating inorganic contaminants (such as uranium) because it induces a high pore-water pH, causing mineral dissolution and subsequent formation of stable precipitates that decrease the mobility of some contaminants. For field application of this treatment, further knowledge of ammonia transport in porous media and the geochemical reactions induced by ammonia treatment is needed. Laboratory studies were conducted to support calculations needed for field treatment design, to quantify advective and diffusive ammonia transport in unsaturated sediments, to evaluate inter-phase (gas/sediment/pore water) reactions, and to study reaction-induced pore-water chemistry changes as a function of ammonia delivery conditions, such as flow rate, gas concentration, and water content. Uranium-contaminated sediment was treated with ammonia gas to demonstrate U immobilization. Ammonia gas quickly partitions into sediment pore water and increases the pH up to 13.2. Injected ammonia gas advection front movement can be reasonably predicted by gas flow rate and equilibrium partitioning. The ammonia gas diffusion rate is a function of the water content in the sediment. Sodium, aluminum, and silica pore-water concentrations increase upon exposure to ammonia and then decline as aluminosilicates precipitate when the pH declines due to buffering. Up to 85% of

  16. Accounting for exhaust gas transport dynamics in instantaneous emission models via smooth transition regression.

    Science.gov (United States)

    Kamarianakis, Yiannis; Gao, H Oliver

    2010-02-15

    Collecting and analyzing high frequency emission measurements has become very usual during the past decade as significantly more information with respect to formation conditions can be collected than from regulated bag measurements. A challenging issue for researchers is the accurate time-alignment between tailpipe measurements and engine operating variables. An alignment procedure should take into account both the reaction time of the analyzers and the dynamics of gas transport in the exhaust and measurement systems. This paper discusses a statistical modeling framework that compensates for variable exhaust transport delay while relating tailpipe measurements with engine operating covariates. Specifically it is shown that some variants of the smooth transition regression model allow for transport delays that vary smoothly as functions of the exhaust flow rate. These functions are characterized by a pair of coefficients that can be estimated via a least-squares procedure. The proposed models can be adapted to encompass inherent nonlinearities that were implicit in previous instantaneous emissions modeling efforts. This article describes the methodology and presents an illustrative application which uses data collected from a diesel bus under real-world driving conditions.

  17. Prediction of critical transport velocity for preventing sand deposition in gas-oil multiphase production and well systems

    Energy Technology Data Exchange (ETDEWEB)

    Bello, O.O.; Reinicke, K.M. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. of Petroleum Engineering; Teodoriu, C. [Texas A and M Univ., College Station, TX (United States). Dept. of Petroleum Engineering

    2008-10-23

    The critical transport velocity is one of the key parameters for gas-oil-sand multiphase production and well system design and safe operation. Existing American Petroleum Institute Recommended Practice 14E (API RP 14E) for the sizing of multiphase flow systems suggests an equation to calculate threshold transport velocity. This equation only considers mixture density and does not account for factors such as fluid properties, gas-liquid flow patterns, sand loading, sand particle size, size distributions, shape factor and density. This work presents an improved computational methodology, which can be applied to estimate the critical transport velocity required to ensure efficient performance of gas-oil-sand multiphase production and well systems. The improved method is based on the modelling of three-phase gas-oil-sand pipe flow physics from first principle. Computations of the critical transport velocities show reasonable agreement with values calculated from mechanistic model (Danielson, 2007) for a relatively wide range of design and operating conditions. Compared with the mechanistic model (Danielson, 2007), the present method has no imposed limitations to the range of applicability. It is also takes into adequate account the effects of operating pressure, flow geometry, sand particle size, size distribution and shape factor, which have considerable influence on the critical transport velocity in gas-oil-sand multiphase production and well systems. (orig.)

  18. Gas transport in low-permeability formations: a review of experimental evidence and modeling approaches

    International Nuclear Information System (INIS)

    Marschall, Paul; Keller, Lukas; Lanyon, Bill; Senger, Rainer

    2012-01-01

    This paper presents a review of phenomenological studies on immiscible fluid flow in porous media, clarifies terminology as used by different disciplines and discusses the different modeling approaches. It concludes with a discussion on the transferability of classical two-phase flow concepts on gas transport processes in low-permeability clay-stones. From a phenomenological point of view, advection and diffusion of dissolved species represent the simplest transport mechanisms in a water-saturated porous medium. The propagation of the dissolved species is controlled by the water velocity and its extent is controlled by the hydrodynamic dispersion - a well-known aggregate representation of the mixing processes due to diffusion, Taylor dispersion and tortuosity. Usually, the dissolution of a gaseous species in water is described by Henry's law, the diffusion of the dissolved gas is represented by Fick's law and the viscous losses of the pore water flow in the pore network are expressed by Darcy's law. Two-phase flow conditions occur when gas invades as a separate phase a water-saturated porous medium. This process is often called drainage, because the non-wetting fluid (gas) displaces a wetting fluid (pore water, 'defending' fluid). The propagation of the gas front is controlled by the complex interaction of gravity, viscous forces and capillary forces. Lenormand et al. (1988) conducted two-phase flow experiments for a wide range of capillary numbers Ca and viscosity ratios M. They identified 3 major flow regimes in the C a -M-space, which they coined viscous fingering, capillary fingering and stable displacement. The regime of stable displacement applies for the special case where the invading fluid has a higher viscosity than the defending fluid (e.g. water imbibition in a gas-filled porous medium). Viscous and capillary fingering are associated with instable displacement of a wetting fluid by the non-wetting fluid, giving rise to phenomena such as migration

  19. Detection of leaks for radioactive tracer in marine duct for transport of liquefied petroleum gas; Deteccion de fugas por radiotrazado en ducto marino para transporte de gas LP

    Energy Technology Data Exchange (ETDEWEB)

    Robles P, E. F.; Benitez S, J. A.; Torre O, J. de la; Cruz S, E. de la; Molina, G.; Hernandez C, J. E.; Flores M, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e mail: efrp@nuclear.inin.mx

    2008-07-01

    In this work the aplication in the oil industry of the technique of radioactive tracer appears for the detection of internal leaks in a submarine duct that gives service as it lines of receipt of liquefied petroleum gas (Gas LP) located in the Mexican coast of the Pacific Ocean. This system of marine pipe is a consistent arrangement of a duct interior of 0.254 m (10 inches) of nominal diameter (N.D.) of steel to the carbon for cryogenic service ASTM A 333, Grade 6, schedule 30, isolated thermally with foam of polyurethane and shielding in a steel tube to the carbon ASTM A 53 Grade A, of 0.508 m (20 inches) N. D., schedule 20, which is recovered by a ballast encircling of concrete of 0.0508 m (2 inches) of thickness, reinforced with mesh metallic, and that 1315 m runs on the marine stratum to a maximum depth of 12.5 m. For the detection of leaks by radiotracer it was used as tracer the radioactive isotope La-140 produced in the TRIGA Mark III Experimental Reactor of the National Institute of Nuclear Research, starting from stable lanthanum nitrate (La(NO{sub 3}){sub 3} 6H{sub 2}O), with an activity of 100 mCi, the one which after having been made logistics tasks, given very particular sea maneuvers and due to the conditions of the work place, in the interior tube was injected in two subsequent stages to cover both duct senses; from earth and from the marine end respectively, there being used fresh water like transport way and submergible sodium iodide detectors (NaI) for the rake of the La-140. At the end of the journeys of pursuit of the radiotracer, it was determine the presence of three leaks points located in the break area of the marine surf to 360 m, 450 m and 495 m of distance of a reference point located in the beach section named Trap of Devils. (Author)

  20. Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface ground water: background, base cases, shallow reservoirs, short-term gas and water transport

    Science.gov (United States)

    Researchers examined gas and water transport between a deep tight shale gas reservoir and a shallow overlying aquifer in the two years following hydraulic fracturing, assuming a pre-existing connecting pathway.

  1. The development of the natural gas transportation network in Brazil: Recent changes to the gas law and its role in co-ordinating new investments

    International Nuclear Information System (INIS)

    Colomer Ferraro, Marcelo; Hallack, Michelle

    2012-01-01

    In Brazil, the consensus that natural gas regulation has failed to attract investments, especially from private companies, culminated in a new law for the natural gas sector, passed in March 2009 (Law No. 11,909). The most significant change this new law introduced was the new governmental role in co-ordinating investments in the transportation sector. The Brazilian government has had to plan pipeline networks, estimate the size of demand for transportation and organise bidding to select investors for new pipeline projects. Although the law has established a clear regulatory framework for the midstream sector, providing stability and the legal certainty necessary for long-term investments in assets with high specificity, it has not been able to fill all of the gaps that remain under Law 9,478. In this sense, besides the challenges related to effective implementation of the regulatory attributes defined in Law 11,909, the absence of certain issues prevents the modified legal structure from encouraging the entry of new players in the transportation sector. This paper has identified, according to the neo-institutional view, the mechanisms of co-ordination introduced by the new law and the limitations of the new regulatory framework. - Highlights: ► Natural gas transportation investment requires some coordination mechanisms. ► The 9,478 Act was not capable to incentive the new player entrance. ► Brazilian natural gas industry is strongly concentrated in Petrobras hands. ► The new Brazilian legal framework aims to reduce transaction costs in gas industry. ► The industrial structure of the gas sector discourages the entrance of new investors.

  2. Experience in developing control integrated multilevel systems for gas transport; Developpement de systemes integres de gestion multi-niveaux pour le transport du gaz

    Energy Technology Data Exchange (ETDEWEB)

    Kostyukov, V.Y. [NIIIS, (Russian Federation); Bityukov, V.S. [Gasprom, (Russian Federation)

    2000-07-01

    This report describes the experience of the integrated control multilevel system (IACS) development and implementation for gas transport at the regional enterprises of JSC 'Gasprom', specificity of IACS creation by the Russian enterprises on the basis of the technical and licensed basic software SCADA Geamatics purchased from AEG company under the contract. (authors)

  3. Achieving deep reductions in US transport greenhouse gas emissions: Scenario analysis and policy implications

    International Nuclear Information System (INIS)

    McCollum, David; Yang, Christopher

    2009-01-01

    This paper investigates the potential for making deep cuts in US transportation greenhouse gas (GHG) emissions in the long-term (50-80% below 1990 levels by 2050). Scenarios are used to envision how such a significant decarbonization might be achieved through the application of advanced vehicle technologies and fuels, and various options for behavioral change. A Kaya framework that decomposes GHG emissions into the product of four major drivers is used to analyze emissions and mitigation options. In contrast to most previous studies, a relatively simple, easily adaptable modeling methodology is used which can incorporate insights from other modeling studies and organize them in a way that is easy for policymakers to understand. Also, a wider range of transportation subsectors is considered here-light- and heavy-duty vehicles, aviation, rail, marine, agriculture, off-road, and construction. This analysis investigates scenarios with multiple options (increased efficiency, lower-carbon fuels, and travel demand management) across the various subsectors and confirms the notion that there are no 'silver bullet' strategies for making deep cuts in transport GHGs. If substantial emission reductions are to be made, considerable action is needed on all fronts, and no subsectors can be ignored. Light-duty vehicles offer the greatest potential for emission reductions; however, while deep reductions in other subsectors are also possible, there are more limitations in the types of fuels and propulsion systems that can be used. In all cases travel demand management strategies are critical; deep emission cuts will not likely be possible without slowing growth in travel demand across all modes. Even though these scenarios represent only a small subset of the potential futures in which deep reductions might be achieved, they provide a sense of the magnitude of changes required in our transportation system and the need for early and aggressive action if long-term targets are to be met.

  4. Peculiarities of charge transport in a semiconductor gas discharge electronic devices

    International Nuclear Information System (INIS)

    Koch, E.; Chivi, M.; Salamov, B.G.; Salamov, B.G.

    2009-01-01

    The memory effect in planar semiconductor gas discharge system at different pressures (15-760) and interelectrode distance (60-445 μm) were experimentally studied. The study was performed on the bases of current-voltage characteristic (CVC) measurements with the time lag of several hours of afterglow periods. The influence of the active space-charge remaining from previous discharge on the breakdown voltage has been analyzed using the CVC method for different conductivity of semiconductor GaAs photocathode. On the other hand, the CVC data for subsequent dates present a correlation of memory effect and hysteresis behaviour. The explanation of such relation is based on the influence of long-lived active charges on the electronic transport mechanism of semiconductor material

  5. Electricity and gas market design to supply the German transport sector with hydrogen

    International Nuclear Information System (INIS)

    Robinius, Martin

    2015-01-01

    The German government has set targets to reduce greenhouse gas emissions by 40% by 2020, 55% by 2030, 70% by 2040 and 80-95% by 2050 compared to 1990 as reference year. As well as meeting other requirements, these targets can be achieved by raising the contribution of renewably-generated power to Germany's gross electricity consumption to 80% by 2050. Based on Germany's potential, intermittent energy sources (IES) such as on- and offshore wind, as well as photovoltaics, are necessary sources that must be utilized in order to achieve these ambitious targets. Because of the intermittency of these sources, there will be times in which surplus power generated could be used for example for the transport sector. During these periods of surplus power, the storage capacity of hydrogen allows for a socalled ''power-to-gas'' concept whereby the surplus power can be used to produce hydrogen and oxygen by means of electrolyzers. The aim of this thesis is to identify and develop a market design that is characterized by high penetration levels of IES, supplemented by the use of hydrogen in the transport sector. Furthermore, the aim was to develop a model in which the electricity and gas sector, including a hydrogen pipeline grid, is represented so as to analyze and validate selected market designs. Therefore, potential electricity and gas markets, as well as the most important potential share and stakeholders of a hydrogen infrastructure, are analyzed. With the model developed in this thesis, an existing energy concept has been developed, analyzed and evaluated. In addition, the distribution of the hydrogen production costs was calculated by employing a Monte Carlo Simulation analysis. The developed energy concept relies on 170 GW onshore and 60 GW offshore wind capacity and these dominate the model. This leads to surplus power, especially in the federal states of Lower Saxony, Schleswig-Holstein and Mecklenburg-Western Pomerania. To supply the

  6. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  7. Building-Resolved CFD Simulations for Greenhouse Gas Transport and Dispersion over Washington DC / Baltimore

    Science.gov (United States)

    Prasad, K.; Lopez-Coto, I.; Ghosh, S.; Mueller, K.; Whetstone, J. R.

    2015-12-01

    The North-East Corridor project aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over urban domains such as Washington DC / Baltimore with high spatial and temporal resolution. Atmospheric transport of tracer gases from an emission source to a tower mounted receptor are usually conducted using the Weather Research and Forecasting (WRF) model. For such simulations, WRF employs a parameterized turbulence model and does not resolve the fine scale dynamics generated by the flow around buildings and communities comprising a large city. The NIST Fire Dynamics Simulator (FDS) is a computational fluid dynamics model that utilizes large eddy simulation methods to model flow around buildings at length scales much smaller than is practical with WRF. FDS has the potential to evaluate the impact of complex urban topography on near-field dispersion and mixing difficult to simulate with a mesoscale atmospheric model. Such capabilities may be important in determining urban GHG emissions using atmospheric measurements. A methodology has been developed to run FDS as a sub-grid scale model within a WRF simulation. The coupling is based on nudging the FDS flow field towards that computed by WRF, and is currently limited to one way coupling performed in an off-line mode. Using the coupled WRF / FDS model, NIST will investigate the effects of the urban canopy at horizontal resolutions of 10-20 m in a domain of 12 x 12 km. The coupled WRF-FDS simulations will be used to calculate the dispersion of tracer gases in the North-East Corridor and to evaluate the upwind areas that contribute to tower observations, referred to in the inversion community as influence functions. Results of this study will provide guidance regarding the importance of explicit simulations of urban atmospheric turbulence in obtaining accurate estimates of greenhouse gas emissions and transport.

  8. A Unified Gas Kinetic Scheme for Transport and Collision Effects in Plasma

    Directory of Open Access Journals (Sweden)

    Dongxin Pan

    2018-05-01

    Full Text Available In this study, the Boltzmann equation with electric acceleration term is discretized and solved by the unified gas-kinetic scheme (UGKS. The charged particle transport driven by electric field is included in the electric acceleration term. To capture non-equilibrium distribution function, the probability distribution functions of gas is discretized in a discrete velocity space. After discretization, the numerical flux for distribution function is computed to update the microscopic and macroscopic states. The flux is decided by an integral solution of Boltzmann equation based on characteristic problem. An electron-ion collision model is introduced in the Boltzmann Bhatnagar-Gross-Krook (BGK equation. This finite volume method for the UGKS couples the free transport and long-range interaction between particles. For simplicity, the electric field induced by charged particles is controlled by the Poisson’s equation, which is solved using the Green’s function for two dimensional plasma system subjected to the symmetry or periodic boundary conditions. Two numerical cases, linear Landau damping and Gaussian beam, are carried out to validate the proposed method. The linear electron plasma wave damping is simulated based on electron-ion collision operator. Comparison results show good accuracy and higher efficiency than particle based methods. Difference between Poisson’s equation and complete electromagnetic Maxwell equation is presented by numerical results based on the two models. Highly non-equilibrium and rarefied plasma flows, such as electron flows driven by electromagnetic field, can be simulated easily. The UGKS-Poisson model is proved to be promising in plasma flow simulation.

  9. The use of the natural-gas pipeline infrastructure for hydrogen transport in a changing market structure

    International Nuclear Information System (INIS)

    Haeseldonckx, Dries; D'haeseleer, William

    2007-01-01

    In this paper, the transport and distribution aspects of hydrogen during the transition period towards a possible full-blown hydrogen economy are carefully looked at. Firstly, the energetic and material aspects of hydrogen transport through the existing natural-gas (NG) pipeline infrastructure is discussed. Hereby, only the use of centrifugal compressors and the short-term security of supply seem to constitute a problem for the NG to hydrogen transition. Subsequently, the possibility of percentwise mixing of hydrogen into the NG bulk is dealt with. Mixtures containing up to 17 vol% of hydrogen should not cause difficulties. As soon as more hydrogen is injected, replacement of end-use applications and some pipelines will be necessary. Finally, the transition towards full-blown hydrogen transport in (previously carrying) NG pipelines is treated. Some policy guidelines are offered, both in a regulated and a liberalised energy (gas) market. As a conclusion, it can be stated that the use of hydrogen-natural gas mixtures seems well suited for the transition from natural gas to hydrogen on a distribution (low pressure) level. However, getting the hydrogen gas to the distribution grid, by means of the transport grid, remains a major issue. In the end, the structure of the market, regulated or liberalised, turns out not to be important. (author)

  10. Growth of Cd0.96Zn0.04Te single crystals by vapor phase gas transport method

    Directory of Open Access Journals (Sweden)

    S. H. Tabatabai Yazdi

    2006-03-01

    Full Text Available   Cd0.96Zn0.04Te crystals were grown using vapor phase gas transport method (VPGT. The results show that dendritic crystals with grain size up to 3.5 mm can be grown with this technique. X-ray diffraction and Laue back-reflection patterns show that dendritic crystals are single-phase, whose single crystal grains are randomly oriented with respect to the gas-transport axis. Electrical measurements, carried out using Van der Pauw method, show that the as-grown crystals have resistivity of about 104 Ω cm and n-type conductivity.

  11. Pyrolytic carbon membranes containing silica: morphological approach on gas transport behavior

    Science.gov (United States)

    Park, Ho Bum; Lee, Sun Yong; Lee, Young Moo

    2005-04-01

    Pyrolytic carbon membrane containing silica (C-SiO 2) is a new-class material for gas separation, and in the present work we will deal with it in view of the morphological changes arising from the difference in the molecular structure of the polymeric precursors. The silica embedded carbon membranes were fabricated by a predetermined pyrolysis step using imide-siloxane copolymers (PISs) that was synthesized from benzophenone tetracarboxylic dianhydrides (BTDA), 4,4'-oxydianiline (ODA), and amine-terminated polydimethylsiloxane (PDMS). To induce different morphologies at the same chemical composition, the copolymers were prepared using one-step (preferentially a random segmented copolymer) sand two-step polymerization (a block segmented copolymer) methods. The polymeric precursors and their pyrolytic C-SiO 2 membranes were analyzed using thermal analysis, atomic force microscopy, and transmission electron microscopy, etc. It was found that the C-SiO 2 membrane derived from the random PIS copolymer showed a micro-structure containing small well-dispersed silica domains, whereas the C-SiO 2 membrane from the block PIS copolymer exhibited a micro-structure containing large silica domains in the continuous carbon matrix. Eventually, the gas transport through these C-SiO 2 membranes was significantly affected by the morphological changes of the polymeric precursors.

  12. Transport of Gas-Phase Anthropogenic VOCs to the Remote Troposphere During the NASA ATom Mission

    Science.gov (United States)

    Hornbrook, R. S.; Apel, E. C.; Hills, A. J.; Asher, E. C. C.; Emmons, L. K.; Blake, D. R.; Blake, N. J.; Simpson, I. J.; Barletta, B.; Meinardi, S.; Montzka, S. A.; Moore, F. L.; Miller, B. R.; Sweeney, C.; McKain, K.; Wofsy, S. C.; Daube, B. C.; Commane, R.; Bui, T. V.; Hanisco, T. F.; Wolfe, G. M.; St Clair, J. M.; Ryerson, T. B.; Thompson, C. R.; Peischl, J.; Ray, E. A.

    2017-12-01

    The NASA Atmospheric Tomography (ATom) project aims to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. During the first two deployments, ATom-1 and ATom-2, which took place August 2016 and February 2017, respectively, a suite of trace gas measurement instruments were deployed on the NASA DC-8 which profiled the atmosphere between 0.2 and 13 km from near-pole to near-pole around the globe, sampling in the most remote regions of the atmosphere over the Arctic, Pacific, Southern, and Atlantic Oceans. Volatile organic compounds (VOCs) with a range of lifetimes from days to decades quantified using the Trace Organic Gas Analyzer (TOGA), Whole Air Sampler (WAS) and Programmable Flask Packages (PFPs) demonstrate a significant impact on the remote atmosphere from urban and industrial sources. Comparisons between the transport and fate of pollutants during Northern Hemisphere summer and winter will be presented. Observations of the distributions of anthropogenic VOCs will be compared with simulations using the Community Atmosphere Model with chemistry (CAM-chem).

  13. Environmental law issues: Offshore oil and gas activities and tanker transportation

    International Nuclear Information System (INIS)

    Chapman, P.M.

    1991-01-01

    The environmental law issues that arise from offshore oil/gas activities and petroleum transport are reviewed, focusing on marine oil pollution and especially on the issues surrounding accidental spills. Some observations are offered on the context of these issues, namely on the risks of oil spills, the difficulty of spill response in the ocean and on shorelines, and the possible environmental damage. Environmental control of petroleum operations is discussed with reference to Canadian regulation, the primary source of which is the Oil and Gas Production and Conservation Act. These regulations require developmental approval for offshore operations, formulation of plans for foreseeable spill emergencies, and compensation to those affected by spills, notably those in the fishing industry. Ship-source oil pollution and spill compensation is discussed with reference to international agreements and the Canada Shipping Act. Some problems and trends with oil spill compensation and recovery for environmental damage are noted in such areas as tanker ship standards, cleanup capabilities, and inadequacy of spill penalties and compensation. 18 refs., 1 fig

  14. Use of Gas Transported Reactants for Uranium Remediation in Vadose Zone Sediments

    International Nuclear Information System (INIS)

    Szecsody, James E.; Zhong, Lirong; Truex, Michael J.; Resch, Charles T.; Williams, Mark D.

    2010-01-01

    This laboratory-scale investigation is focused on decreasing mobility of uranium in subsurface contaminated sediments in the vadose zone by in situ geochemical manipulation at low water content. This geochemical manipulation of the sediment surface phases included reduction, pH change (acidic and alkaline), and additions of chemicals (phosphate, ferric iron) to form specific precipitates. Reactants were advected into 1-D columns packed with Hanford 200 area U-contaminated sediment as a reactive gas (for CO2, NH3, H2S, SO2), with a 0.1% water content mist (for NaOH, Fe(III), HCl, PO4) and with a 1% water content foam (for PO4). Because uranium is present in the sediment in multiple phases, changes in U surface phases were evaluated with a series of liquid extractions that dissolve progressively less soluble phases and electron microbe identification of mineral phases. In terms of the short-term decrease in U mobility (in decreasing order), NH3, NaOH mist, CO2, HCl mist, and Fe(III) mist showed 20% to 35% change in U surface phases. The two reductive gas treatments (H2S and SO2) showed little change. For long-term decrease in U transport, mineral phases created that had low solubility (phosphates, silicates) were desired, so NH3, phosphates (mist and foam delivered), and NaOH mist showed the greatest formation of these minerals.

  15. Transition of Gas-Liquid Stratified Flow in Oil Transport Pipes

    Directory of Open Access Journals (Sweden)

    D. Lakehal

    2011-12-01

    Full Text Available Large-Scale Simulation results of the transition of a gas-liquid stratified flow to slug flow regime in circular 3D oil transport pipes under turbulent flow conditions expressed. Free surface flow in the pipe is treated using the Level Set method. Turbulence is approached via the LES and VLES methodologies extended to interfacial two-phase flows. It is shown that only with the Level Set method the flow transition can be accurately predicted, better than with the two-fluid phase-average model. The transition from stratified to slug flow is found to be subsequent to the merging of the secondary wave modes created by the action of gas shear (short waves with the first wave mode (high amplitude long wave. The model is capable of predicting global flow features like the onset of slugging and slug speed. In the second test case, the model predicts different kinds of slugs, the so-called operating slugs formed upstream that fill entirely the pipe with water slugs of length scales of the order of 2-4 D, and lower size (1-1.5 D disturbance slugs, featuring lower hold-up (0.8-0.9. The model predicts well the frequency of slugs. The simulations revealed important parameter effects on the results, such as two-dimensionality, pipe length, and water holdup.

  16. Subsurface fate and transport of cyanide species at a manufactured-gas plant site

    International Nuclear Information System (INIS)

    Ghosh, R.S.; Dzombak, D.A.; Luthy, R.G.; Nakles, D.V.

    1999-01-01

    Cyanide is present at manufactured-gas plant (MGP) sites in oxide-box residuals, which were often managed on-site as fill during active operations. Cyanide can leach from these materials, causing groundwater contamination. Speciation, fate, and transport of cyanide in a sand-gravel aquifer underlying an MGP site in the upper Midwest region of the US were studied through characterization, monitoring, and modeling of a plume of cyanide-contaminated groundwater emanating from the site. Results indicate that cyanide in the groundwater is primarily in the form of iron-cyanide complexes (>98%), that these complexes are stable under the conditions of the aquifer, and that they are transported as nonreactive solutes in the sand-gravel aquifer material. Weak-acid-dissociable cyanide, which represents a minute fraction of total cyanide in the site groundwater, may undergo chemical-biological degradation in the sand-gravel aquifer. It seems that dilution may be the only natural attenuation mechanism for iron-cyanide complexes in sand-gravel aquifers at MGP sites

  17. Electrical detection of spin transport in Si two-dimensional electron gas systems

    Science.gov (United States)

    Chang, Li-Te; Fischer, Inga Anita; Tang, Jianshi; Wang, Chiu-Yen; Yu, Guoqiang; Fan, Yabin; Murata, Koichi; Nie, Tianxiao; Oehme, Michael; Schulze, Jörg; Wang, Kang L.

    2016-09-01

    Spin transport in a semiconductor-based two-dimensional electron gas (2DEG) system has been attractive in spintronics for more than ten years. The inherent advantages of high-mobility channel and enhanced spin-orbital interaction promise a long spin diffusion length and efficient spin manipulation, which are essential for the application of spintronics devices. However, the difficulty of making high-quality ferromagnetic (FM) contacts to the buried 2DEG channel in the heterostructure systems limits the potential developments in functional devices. In this paper, we experimentally demonstrate electrical detection of spin transport in a high-mobility 2DEG system using FM Mn-germanosilicide (Mn(Si0.7Ge0.3)x) end contacts, which is the first report of spin injection and detection in a 2DEG confined in a Si/SiGe modulation doped quantum well structure (MODQW). The extracted spin diffusion length and lifetime are l sf = 4.5 μm and {τ }{{s}}=16 {{ns}} at 1.9 K respectively. Our results provide a promising approach for spin injection into 2DEG system in the Si-based MODQW, which may lead to innovative spintronic applications such as spin-based transistor, logic, and memory devices.

  18. The regulation of greenhouse gas emissions in the field of transport

    International Nuclear Information System (INIS)

    2009-03-01

    Since 1990, CO 2 emissions in the transport sector have increased by nearly 20%, mainly because of increased car traffic. Reducing them by 20% between now and 2020, in accordance with the draft law tabled by the Grenelle Environment Forum - and by much more between now and 2050 in the context of reducing European emissions by 75% - presupposes recourse to economic instruments such as the climate-energy contribution envisaged by the Forum. However, the methods of evaluation and implementation remain to be defined. The order of magnitude of such instruments could correspond to the value defined for the socio-economic calculations of public projects by a Centre d'Analyse Strategique mission that was set up at the request of the Prime Minister and chaired by Alain Quinet. It will thus be close to 30 euros per CO 2 ton today, rising to 100 eu