Transient dynamic crack propagation in gas pressurised pipelines

International Nuclear Information System (INIS)

Caldis, E.S.; Owen, D.R.J.; Taylor, C.

1983-01-01

The prime limitation of dynamic fracture analysis is the lack of a fundamental crack advance theory which can be easily and economically adopted for use with numerical models. The necessity for the inclusion of inertia effects in the solution of certain problem classes is now evident, but most transient dynamic fracture models considered to date include (of necessity) some intuitive/empirical parameters with a frequent need of a priori knowledge of experimental solutions. The particular problem considered in this study is Mode I transient dynamic crack propagation in gas pressurised pipelines. The steel pipe is modelled using thin shell Semiloof finite elements and its transient response is coupled to a one-dimensional finite element model of the compressible gas equations, incorporating a lateral gas flow parameter. The pipe is governed by the usual dynamic equilibrium equation which is discretised in the time domain by a central difference explicit algorithm. The compressible gas response is modelled by the Continuity and Momentum equations and time discretisation is performed by means of a fully backward difference scheme in time. (orig./GL)

Proceedings of the 1993 InterAmerican Petroleum and Gas Conference

International Nuclear Information System (INIS)

1993-01-01

The 1993 InterAmerican Petroleum and Gas Conference (IPGC) took place September 27--28, 1993, in Dallas Texas. The EPGC was sponsored by the US Department of Energy, organized by the East-West Center and hosted by the Institute for the Study of Earth and Man at Southern Methodist University. The IPGC brought together senior oil industry and government representatives from the United States and Latin America to discuss energy security and more efficient resource utilization through improved cooperation and integration of upstream and downstream activities in the United States and Latin America with an emphasis on technology investments and complementary trade strategies. Special attention was given to the growing opportunities for private and foreign investment, trade and joint commercial ventures between US and Latin American companies. The papers included in these proceedings include most of the presentations offered at the conference that addressed a number of key issues including financial challenges of the hydrocarbon sector, regional and national outlook on the world oil market, upstream and downstream outlook, role of natural gas, and environment and infrastructure requirements. Selected papers have been processed separately for inclusion in the Energy Science and Technology database

Cloud-particle galactic gas dynamics and star formation

International Nuclear Information System (INIS)

Roberts, W.W. Jr.

1983-01-01

Galactic gas dynamics, spiral structure, and star formation are discussed in the context of N-body computational studies based on a cloud-particle model of the interstellar medium. On the small scale, the interstellar medium appears to be cloud-dominated and supernova-perturbed. The cloud-particle model simulates cloud-cloud collisions, the formation of stellar associations, and supernova explosions as dominant local processes. On the large scale in response to a spiral galactic gravitational field, global density waves and galactic shocks develop with large-scale characteristics similar to those found in continuum gas dynamical studies. Both the system of gas clouds and the system of young stellar associations forming from the clouds share in the global spiral structure. However, with the attributes of neither assuming a continuum of gas (as in continuum gas dynamical studies) nor requiring a prescribed equation of state such as the isothermal condition so often employed, the cloud-particle picture retains much of the detail lost in earlier work: namely, the small-scale features and structures so important in understanding the local, turbulent state of the interstellar medium as well as the degree of raggedness often observed superposed on global spiral structure. (Auth.)

Systems of quasilinear equations and their applications to gas dynamics

CERN Document Server

Roždestvenskiĭ, B L; Schulenberger, J R

1983-01-01

This book is essentially a new edition, revised and augmented by results of the last decade, of the work of the same title published in 1968 by "Nauka." It is devoted to mathematical questions of gas dynamics. Topics covered include Foundations of the Theory of Systems of Quasilinear Equations of Hyperbolic Type in Two Independent Variables; Classical and Generalized Solutions of One-Dimensional Gas Dynamics; Difference Methods for Solving the Equations of Gas Dynamics; and Generalized Solutions of Systems of Quasilinear Equations of Hyperbolic Type.

Ideal gas approximation for a two-dimensional rarefied gas under Kawasaki dynamics

NARCIS (Netherlands)

Gaudillière, A.; Hollander, den W.Th.F.; Nardi, F.R.; Olivieri, E.; Scoppola, E.

2009-01-01

In this paper we consider a two-dimensional lattice gas under Kawasaki dynamics, i.e., particles hop around randomly subject to hard-core repulsion and nearest-neighbor attraction. We show that, at fixed temperature and in the limit as the particle density tends to zero, such a gas evolves in a way

Microscopic approach to string gas cosmology

Science.gov (United States)

Evnin, Oleg

2014-03-01

In this contribution to the proceedings of the Conference on Modern Physics of Compact Stars and Relativistic Gravity in Yerevan, Armenia (September 18-21, 2013), I review recent work attempting to give a fundamental definition to string evolution in a dynamical, fully compact universe, and present a sketch of how the resulting formalism can be used for addressing questions of phenomenological significance in the field of string gas cosmology.

The computer simulation of 3d gas dynamics in a gas centrifuge

Science.gov (United States)

Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

2016-09-01

We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there.

The computer simulation of 3d gas dynamics in a gas centrifuge

International Nuclear Information System (INIS)

Borman, V D; Bogovalov, S V; Borisevich, V D; Tronin, I V; Tronin, V N

2016-01-01

We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there. (paper)

Spin dynamics in a two-dimensional quantum gas

DEFF Research Database (Denmark)

Pedersen, Poul Lindholm; Gajdacz, Miroslav; Deuretzbacher, Frank

2014-01-01

We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions with superimp......We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions...

Gas-Dynamic Methods to Reduce Gas Flow Nonuniformity from the Annular Frames of Gas Turbine Engines

Science.gov (United States)

Kolmakova, D.; Popov, G.

2018-01-01

Gas flow nonuniformity is one of the main sources of rotor blade vibrations in the gas turbine engines. Usually, the flow circumferential nonuniformity occurs near the annular frames, located in the flow channel of the engine. This leads to the increased dynamic stresses in blades and consequently to the blade damage. The goal of the research was to find an acceptable method of reducing the level of gas flow nonuniformity. Two different methods were investigated during this research. Thus, this study gives the ideas about methods of improving the flow structure in gas turbine engine. Based on existing conditions (under development or existing engine) it allows the selection of the most suitable method for reducing gas flow nonuniformity.

Canadian natural gas market: dynamics and pricing

International Nuclear Information System (INIS)

2000-01-01

This publication by the National Energy Board is part of a continuing program of assessing applications for long-term natural gas export licences. The market-based procedure used by the Board is based on the premise that the marketplace will generally operate in a way that will ensure that Canadian requirements for natural gas will be met at fair market prices. The market--based procedure consists of a public hearing and a monitoring component. The monitoring component involves the on-going assessment of Canadian energy markets to provide analyses of major energy commodities on either an individual or integrated commodity basis. This report is the result of the most recent assessment . It identifies factors that affect natural gas prices and describes the functioning of regional markets in Canada. It provides an overview of the energy demand, including recent trends, reviews the North American gas supply and markets, the natural gas pricing dynamics in Canada, and a regional analysis of markets, prices and dynamics in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec and the Atlantic provinces. In general, demand growth outstripped growth in supply, but natural gas producers throughout North America have been responding to the current high price environment with aggressive drilling programs. The Board anticipates that in time, there will be a supply and demand response and accompanying relief in natural gas prices. A review of the annual weighted average border price paid for Alberta gas indicates that domestic gas users paid less than export customers until 1998, at which point the two prices converged, suggesting that Canadians have had access to natural gas at prices no less favourable than export customers. The influence of electronic trading systems such as NYMEX and AECO-C/NIT have had significant impact on the pricing of natural gas. These systems, by providing timely information to market participants. enables them to manage price

Gas dynamics in strong centrifugal fields

OpenAIRE

Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

2017-01-01

Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of $10^6$g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wa...

Dynamic pressure as a measure of gas turbine engine (GTE) performance

International Nuclear Information System (INIS)

Rinaldi, G; Stiharu, I; Packirisamy, M; Nerguizian, V; Landry, R Jr; Raskin, J-P

2010-01-01

Utilizing in situ dynamic pressure measurement is a promising novel approach with applications for both control and condition monitoring of gas turbine-based propulsion systems. The dynamic pressure created by rotating components within the engine presents a unique opportunity for controlling the operation of the engine and for evaluating the condition of a specific component through interpretation of the dynamic pressure signal. Preliminary bench-top experiments are conducted with dc axial fans for measuring fan RPM, blade condition, surge and dynamic temperature variation. Also, a method, based on standing wave physics, is presented for measuring the dynamic temperature simultaneously with the dynamic pressure. These tests are implemented in order to demonstrate the versatility of dynamic pressure-based diagnostics for monitoring several different parameters, and two physical quantities, dynamic pressure and dynamic temperature, with a single sensor. In this work, the development of a dynamic pressure sensor based on micro-electro-mechanical system technology for in situ gas turbine engine condition monitoring is presented. The dynamic pressure sensor performance is evaluated on two different gas turbine engines, one having a fan and the other without

Key factors of combustion from kinetics to gas dynamics

CERN Document Server

Rubtsov, Nikolai M

2017-01-01

This book summarizes the main advances in the mechanisms of combustion processes. It focuses on the analysis of kinetic mechanisms of gas combustion processes and experimental investigation into the interrelation of kinetics and gas dynamics in gas combustion. The book is complimentary to the one previously published, The Modes of Gaseous Combustion.

Technologies for gas cooled reactor decommissioning, fuel storage and waste disposal. Proceedings of a technical committee meeting

International Nuclear Information System (INIS)

1998-09-01

Gas cooled reactors (GCRs) and other graphite moderated reactors have been important part of the world's nuclear programme for the past four decades. The wide diversity in status of this very wide spectrum of plants from initial design to decommissioning was a major consideration of the International Working group on Gas Cooled Reactors which recommended IAEA to convene a Technical Committee Meeting dealing with GCR decommissioning, including spent fuel storage and radiological waste disposal. This Proceedings includes papers 25 papers presented at the Meeting in three sessions entitled: Status of Plant Decommissioning Programmes; Fuels Storage Status and Programmes; waste Disposal and decontamination Practices. Each paper is described here by a separate abstract

Gas-liquid reactor / separator: dynamics and operability characteristics

NARCIS (Netherlands)

Ranade, V.; Kuipers, J.A.M.; Versteeg, Geert

1999-01-01

A comprehensive mathematical model is developed to simulate gas¿liquid reactor in which both, reactants as well as products enter or leave the reactor in gas phase while the reactions take place in liquid phase. A case of first-order reaction (isothermal) was investigated in detail using the dynamic

Gas-Phase Molecular Dynamics: Theoretical Studies in Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu, H.G.; Muckerman, J.T.

2010-06-01

The goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods.

Gas calorimeter workshop: proceedings

International Nuclear Information System (INIS)

1982-01-01

Gas calorimeters combining functions of energy measurement and fine tracking have become more and more popular in the past few years. They help identify muons, gammas, electrons, and hadrons within dense tracks from transverse and longitudinal shower development. Fine segmentation capability using pads and strips on the cathodes have made gas-sampling calorimeters very attractive for colliding-beam detectors where a large multiplicity of particles are detected in a projected geometry. Linearity, energy resolution, shower position resolution, multishower resolution, and calibration questions were discussed in detail at the workshop. Ease of energy calibration by monitoring radioactive sources, good gain uniformity, and gain stability obtained were among the topics of the speakers. There was a discussion session on the operation mode of wire chambers. Gas calorimeters have been used successfully at CERN, Cornell, Fermilab, and SLAC for experiments. Some of the results from those large-scale devices were reported. Future usage of gas-sampling calorimeters for colliding-beam experiments at Fermilab and CERN were discussed. Wire chambers using extruded conductive plastic tubes have made construction easy of pads and strips which can conveniently read out induced signals from the cathode. The results of extensive studies on such devices were discussed. Separate entries were prepared for the data base for the 17 papers presented

Rarefied gas dynamics - Vol. 2

International Nuclear Information System (INIS)

Belotserkovskii, O.M.; Kogan, M.N.; Kutateladze, S.S.; Rebrov, A.K.

1985-01-01

Volume 2 presents information on the following topics: analytical formulae for cross sections and rate constants of elementary processes in gases; effects of initial molecular states in high-energy scattering of molecular beams; cesium vapor jet target produced with a supersonic nozzle; electron beam diagnostics of high temperature rarefied gas flows; free jet as an object of nonequilibrium processes investigation; free jet expansion with a strong condensation effect; rotational relaxation in high temperature jets of nitrogen; laser induced fluorescence study of free jet expansions; homogeneous condensation of nitrogen in transonic flow; the microscopic theory of clustering and nucleation; diagnostics of clusters in molecular beams; experimental studies of water-aerosol explosive vaporization; laser probing of cluster formations and dissociation in molecular beams; free molecule drag on helium clusters; kinetic model of gas suspension; molecular diffusion through a fine-pored filter versus resonate IR-radiation intensity; and rarefied gas dynamics as related to controlled thermonuclear fusion

Insight conference proceedings : natural gas

International Nuclear Information System (INIS)

2005-01-01

The state of Quebec's energy industry was discussed at this conference. Quebec's energy market is distinct by the diversity of its clients, the resource exploitation sector and its types of industries. As such, the energy needs are specific and the strategies for developing natural gas should be adapted to meet these needs. This conference focused on recent energy policy developments at Quebec's Office of Energy and other regulatory bodies. Topics of discussion included the risks and opportunities of the natural gas export market; volatile gas prices; public consultation processes; perspectives of large energy consumers; hydrocarbon potential and exploration in Quebec; natural gas exploration and development in Quebec; energy security and strategies to address carbon dioxide emissions. Other topics of discussion included the investment climate in Quebec; the profitability of Canada's oil and gas sector and refining capacity in Quebec. The conference featured 17 presentations, of which 6 have been indexed separately for inclusion in this database. refs., tabs., figs

Free Piston Problem for Isentropic Gas Dynamics

OpenAIRE

Takeno, Shigeharu

1995-01-01

We consider the existence of the generalized solution for a free piston problem for isentropic gas dynamics. By the compensated compactness theory, we can show that an approximate solution converges to a generalized solution.

Gas dynamics in strong centrifugal fields

Energy Technology Data Exchange (ETDEWEB)

Bogovalov, S.V.; Kislov, V.A.; Tronin, I.V. [National research nuclear university “MEPhI”, Kashirskoje shosse, 31,115409, Moscow (Russian Federation)

2015-03-10

Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 106g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity.

Fluid dynamic computations of the flue-gas channel in an evaporative gas turbine

Energy Technology Data Exchange (ETDEWEB)

Engdar, Ulf

1999-12-01

A new pilot power plant, based on an advanced thermodynamic cycle, called Evaporative Gas Turbine (EvGT), has been erected at the department for Heat- and Power Engineering, Lund University. The pilot plant is a part of the Evaporative Gas Turbine project, a cooperation between universities and industry in Sweden. The fluid dynamics layout of the plant is not optimized and hence no pressure drop reduction modifications have been made on the plant. A pressure drop will decrease the efficiency of the plant. Temperature measurements have shown that there maybe is a temperature stratification of the flow on the flue-gas side downstream the recuperator. A temperature stratification will influence the measurements and heat exchangers. The objective of this thesis is to investigate pressure drops and temperature stratification in the flue-gas channel between the recuperator and the economizer at the present pilot plant. Further, suggest modifications that can reduce pressure drops and/or a temperature stratification of the flow. The way of dealing with these problems was to utilize computational fluid dynamics (CFD), which makes it possible to compute the flue-gas channel in detail. The CFD-computations were conducted with a commercial computer program, called Star-CD. The pressure drop was calculated as the sum of the static- and the dynamic- pressure drop. No information about the shape of the temperature stratification was available to investigate whether a stratification will sustain or vanish. Therefore, two different temperature profiles was applied at the outlet of the recuperator. To compare modifications with the present plant, concerning the temperature stratification, a temperature rms-value was utilized as a measure of the deviation from a flow with constant temperature over a cross-section. The computations show that the pressure drop in the flue-gas channel is small compared to the pressure drop over the recuperator. Therefore, no pressure drop reducing

Dynamics of the world gas trade

International Nuclear Information System (INIS)

Chabrelie, M.F.

2004-01-01

The increasing distances between gas producing and gas consuming areas have led to foresee a considerable development of the international exchanges with a rate of about 3.5% per year up to 2020. The fluxes should represent about 32% of the commercialized production. The maritime transport by methane tanker ship will be certainly the winner of this dynamics, allowing, thanks to its flexibility, to adjust the offer to the demand of a more and more global market. This is today the bet of an industry which, motivated by technological improvements and markets potentialities, invests massively in new infrastructures. (J.S.)

Excited-state dynamics of a ruthenium(II) catalyst studied by transient photofragmentation in gas phase and transient absorption in solution

Energy Technology Data Exchange (ETDEWEB)

Imanbaew, D.; Nosenko, Y. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Kerner, C. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Chevalier, K.; Rupp, F. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Riehn, C., E-mail: riehn@chemie.uni-kl.de [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Thiel, W.R. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Diller, R. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany)

2014-10-17

Graphical abstract: - Highlights: • Ultrafast dynamics of new Ru(II) catalysts investigated in gas phase and solution. • Catalyst activation (HCl loss) achieved in ion trap by UV photoexcitation. • Electronic relaxation proceeds by IVR and IC followed by ground state dissociation. • No triplet formation in contrast to other Ru-polypyridine complexes. • Solvent prohibits catalyst activation in solution by fast vibrational cooling. - Abstract: We report studies on the excited state dynamics of new ruthenium(II) complexes [(η{sup 6}-cymene)RuCl(apypm)]PF{sub 6} (apypm=2-NR{sub 2}-4-(pyridine-2-yl)-pyrimidine, R=CH{sub 3} (1)/H (2)) which, in their active form [1{sup +}-HCl] and [2{sup +}-HCl], catalyze the transfer hydrogenation of arylalkyl ketones in the absence of a base. The investigations encompass femtosecond pump–probe transient mass spectrometry under isolated conditions and transient absorption spectroscopy in acetonitrile solution, both on the cations [(η{sup 6}-cymene)RuCl(apypm)]{sup +} (1{sup +}, 2{sup +}). Gas phase studies on mass selected ions were performed in an ESI ion trap mass spectrometer by transient photofragmentation, unambiguously proving the formation of the activated catalyst species [1{sup +}-HCl] or [2{sup +}-HCl] after photoexcitation being the only fragmentation channel. The primary excited state dynamics in the gas phase could be fitted to a biexponential decay, yielding time constants of <100 fs and 1–3 ps. Transient absorption spectroscopy performed in acetonitrile solution using femtosecond UV/Vis and IR probe laser pulses revealed additional deactivation processes on longer time scales (∼7–12 ps). However, the formation of the active catalyst species after photoexcitation could not be observed in solution. The results from both studies are compared to former CID investigations and DFT calculations concerning the activation mechanism.

Proceedings of "Optical Probes of Dynamics in Complex Environments"

Energy Technology Data Exchange (ETDEWEB)

Sension, R; Tokmakoff, A

2008-04-01

This document contains the proceedings from the symposium on Optical Probes of Dynamics in Complex Environments, which organized as part of the 235th National Meeting of the American Chemical Society in New Orleans, LA from April 6 to 10, 2008. The study of molecular dynamics in chemical reaction and biological processes using time ƒresolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time resolved spectroscopy is central to all of DOEs grand challenges for fundamental energy science. This symposium brought together leaders in the field of ultrafast spectroscopy, including experimentalists, theoretical chemists, and simulators, to discuss the most recent scientific and technological advances. DOE support for this conference was used to help young US and international scientists travel to the meeting. The latest technology in ultrafast infrared, optical, and xray spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

Proceedings of the KSME 2009 fall annual meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

This proceedings contains articles of the KSME 2009 fall annual meeting. It was held on 4-6 Nov, 2009 in Pyeongchang, Korea. This proceedings is comprised of 10 sessions. The main subject titles of session are as follows: materials and fracture mechanics, CAE and applied mechanics, dynamics and control, fabrication and design, reliability, biotechnology, micro/nano-mechanics, thermodynamics, fluid mechanics, energy and dynamics. (Yi, J. H.)

Dynamics of a massive piston in an ideal gas

International Nuclear Information System (INIS)

Chernov, N I; Lebowitz, J L; Sinai, Yakov G

2002-01-01

This survey is a study of a dynamical system consisting of a massive piston in a cubic container of large size L filled with an ideal gas. The piston has mass M∼L 2 and undergoes elastic collisions with N∼L 3 non-interacting gas particles of mass m=1. It is found that under suitable initial conditions there is a scaling regime with time and space scaled by L in which the motion of the piston and the one-particle distribution of the gas satisfy autonomous coupled equations (hydrodynamic equations) such that in the limit L→∞ the mechanical trajectory of the piston converges in probability to the solution of the hydrodynamic equations for a certain period of time. There is also a heuristic discussion of the dynamics of the system on longer intervals of time

Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu H. G.; Muckerman, J.T.

2012-05-29

The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.

World Gas Conference 1997. Working committee J. World gas prospects, strategies and economics

International Nuclear Information System (INIS)

1997-01-01

This volume of the proceedings contains the report of the International Gas Union's Working Committee J - World gas prospects, strategies and economics - and 7 oral papers dealing with natural gas supply and demand and transmission. (LN)

A systematic investigation of SO2 removal dynamics by coal-based activated cokes: The synergic enhancement effect of hierarchical pore configuration and gas components

Science.gov (United States)

Sun, Fei; Gao, Jihui; Liu, Xin; Tang, Xiaofan; Wu, Shaohua

2015-12-01

For the aim to break through the long-term roadblock to porous carbon based SO2 removal technology, typical coal-based activated cokes differing in terms of surface area, pore configuration and surface functional properties, were employed to investigate the SO2 removal dynamics. Among the employed activated cokes, the one with a hierarchically porous structure greatly enhanced the SO2 removal dynamics under the simulated flue gas compositions. More detailedly, SO2 separate adsorption property under normal temperature and pressure evidenced that monolayer SO2 molecules anchoring on micropore surface is the main adsorption pattern. The catalytic oxidation of SO2 follows the Eley-Rideal mechanism by which SO2 was firstly oxidized by molecular oxygen into SO3 which could depart partially to release the active sites for further adsorption. For the role of hierarchical pore configuration, it was proposed that micropores serve as gas adsorption and reaction accommodation, meso-/macropores act as byproduct H2SO4 transport and buffing reservoirs, which may in turn gives rise to the recovery of active sites in micropores and guarantees the continuous proceeding of sulfur-containing species transformation in the micropores. The present results suggest that pore configuration or interconnecting pattern, but not mere surface area or pore volume, should be favourably considered for optimizing heterogeneous gas-solid adsorption and reaction.

Dynamics of gas in a rotating galaxy

International Nuclear Information System (INIS)

Mulder, W.A.

1985-01-01

This thesis contains a series of papers that deal with some aspects of the gas-dynamics in a disk galaxy. The dissertation is divided in three parts. In the first part, the three dimensional response to the rotating barred potential is studied. Here, the strongest simplication is made: the pressure is neglected. This turns the problem from a global into a local one and leaves the equations of motion for a star or test particle. What if the pressure term is included. It turned out that no efficient numerical methods for computing steady gas flows with strong shocks were available. The key assumption of the second part of this thesis is the existence of a stationary solution. In that case, significant short-cuts over time-dependent integration schemes must be attainable. The various steps that lead to an efficient numerical method are described. In the third part of this dissertation, a two-dimensional code was developed. Technical aspects of the computer program are described as well as the properties of the computed quasi-steady solution. An initial global gas dynamical model for our Galaxy is constructed from one of the solutions. Here the main problem is the determination of the position of the sun in the model. (Auth.)

The origin of the hot metal-poor gas in NGC 1291 - Testing the hypothesis of gas dynamics as the cause of the gas heating

NARCIS (Netherlands)

Perez, [No Value; Freeman, K

In this paper we test the idea that the low-metallicity hot gas in the centre of NGC 1291 is heated via a dynamical process. In this scenario, the gas from the outer gas-rich ring loses energy through bar-driven shocks and falls to the centre. Heating of the gas to X-ray temperatures comes from the

Dynamic safety assessment of natural gas stations using Bayesian network

Energy Technology Data Exchange (ETDEWEB)

Zarei, Esmaeil, E-mail: smlzarei65@gmail.com [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Azadeh, Ali [School of Industrial and Systems Engineering, Center of Excellence for Intelligent-Based Experimental Mechanic, College of Engineering, University of Tehran (Iran, Islamic Republic of); Khakzad, Nima [Safety and Security Science Section, Delft University of Technology, Delft (Netherlands); Aliabadi, Mostafa Mirzaei [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Mohammadfam, Iraj, E-mail: mohammadfam@umsha.ac.ir [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of)

2017-01-05

Graphical abstract: Dynamic cause-consequence analysis of the regulator system failure using BN. - Highlights: • A dynamic and comprehensive QRA (DCQRA) framework is proposed for safety assessment of CGSs. • Bow-tie diagram and Bayesian network are employed for accident scenario modeling. • Critical basic events and minimal cut sets are identified using probability updating. - Abstract: Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations. In this approach, a FMEA is used for hazard analysis while a Bow-tie diagram and Bayesian network are employed to model the worst-case accident scenario and to assess the risks. The results have indicated that the failure of the regulator system was the worst-case accident scenario with the human error as the most contributing factor. Thus, in risk management plan of natural gas stations, priority should be given to the most probable root events and main contribution factors, which have identified in the present study, in order to reduce the occurrence probability of the accident scenarios and thus alleviate the risks.

Dynamic safety assessment of natural gas stations using Bayesian network

International Nuclear Information System (INIS)

Zarei, Esmaeil; Azadeh, Ali; Khakzad, Nima; Aliabadi, Mostafa Mirzaei; Mohammadfam, Iraj

2017-01-01

Graphical abstract: Dynamic cause-consequence analysis of the regulator system failure using BN. - Highlights: • A dynamic and comprehensive QRA (DCQRA) framework is proposed for safety assessment of CGSs. • Bow-tie diagram and Bayesian network are employed for accident scenario modeling. • Critical basic events and minimal cut sets are identified using probability updating. - Abstract: Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations. In this approach, a FMEA is used for hazard analysis while a Bow-tie diagram and Bayesian network are employed to model the worst-case accident scenario and to assess the risks. The results have indicated that the failure of the regulator system was the worst-case accident scenario with the human error as the most contributing factor. Thus, in risk management plan of natural gas stations, priority should be given to the most probable root events and main contribution factors, which have identified in the present study, in order to reduce the occurrence probability of the accident scenarios and thus alleviate the risks.

Emergent dynamic structures and statistical law in spherical lattice gas automata

Science.gov (United States)

Yao, Zhenwei

2017-12-01

Various lattice gas automata have been proposed in the past decades to simulate physics and address a host of problems on collective dynamics arising in diverse fields. In this work, we employ the lattice gas model defined on the sphere to investigate the curvature-driven dynamic structures and analyze the statistical behaviors in equilibrium. Under the simple propagation and collision rules, we show that the uniform collective movement of the particles on the sphere is geometrically frustrated, leading to several nonequilibrium dynamic structures not found in the planar lattice, such as the emergent bubble and vortex structures. With the accumulation of the collision effect, the system ultimately reaches equilibrium in the sense that the distribution of the coarse-grained speed approaches the two-dimensional Maxwell-Boltzmann distribution despite the population fluctuations in the coarse-grained cells. The emergent regularity in the statistical behavior of the system is rationalized by mapping our system to a generalized random walk model. This work demonstrates the capability of the spherical lattice gas automaton in revealing the lattice-guided dynamic structures and simulating the equilibrium physics. It suggests the promising possibility of using lattice gas automata defined on various curved surfaces to explore geometrically driven nonequilibrium physics.

Emergent dynamic structures and statistical law in spherical lattice gas automata.

Science.gov (United States)

Yao, Zhenwei

2017-12-01

Various lattice gas automata have been proposed in the past decades to simulate physics and address a host of problems on collective dynamics arising in diverse fields. In this work, we employ the lattice gas model defined on the sphere to investigate the curvature-driven dynamic structures and analyze the statistical behaviors in equilibrium. Under the simple propagation and collision rules, we show that the uniform collective movement of the particles on the sphere is geometrically frustrated, leading to several nonequilibrium dynamic structures not found in the planar lattice, such as the emergent bubble and vortex structures. With the accumulation of the collision effect, the system ultimately reaches equilibrium in the sense that the distribution of the coarse-grained speed approaches the two-dimensional Maxwell-Boltzmann distribution despite the population fluctuations in the coarse-grained cells. The emergent regularity in the statistical behavior of the system is rationalized by mapping our system to a generalized random walk model. This work demonstrates the capability of the spherical lattice gas automaton in revealing the lattice-guided dynamic structures and simulating the equilibrium physics. It suggests the promising possibility of using lattice gas automata defined on various curved surfaces to explore geometrically driven nonequilibrium physics.

THE INFLUENCE OF AEROSOL GAS-DYNAMIC SUSPENSION CLEANING ON SURFACE OF THE AIRCRAFT PARTS

Directory of Open Access Journals (Sweden)

Vitaly D. Hizhko

2008-02-01

Full Text Available  The specificity of the surface microgeometry formation under the influence of aerosol gas-dynamic suspension flow was considered. The composition and character of metallic surface layer formation of aircraft parts was investigated. The possibility of surface material composition and properties adjustment changing aerosol gas-dynamic suspension flow parameters was determined. The hypothesis about the possibility of using aerosol gas-dynamic suspension flow to form corrosion-resistant coating on the detail metallic surfaces was set up.

Effects of gas periodic stimulation on key enzyme activity in gas double-dynamic solid state fermentation (GDD-SSF).

Science.gov (United States)

Chen, Hongzhang; Shao, Meixue; Li, Hongqiang

2014-03-05

The heat and mass transfer have been proved to be the important factors in air pressure pulsation for cellulase production. However, as process of enzyme secretion, the cellulase formation has not been studied in the view of microorganism metabolism and metabolic key enzyme activity under air pressure pulsation condition. Two fermentation methods in ATPase activity, cellulase productivity, weight lose rate and membrane permeability were systematically compared. Results indicated that gas double-dynamic solid state fermentation had no obviously effect on cell membrane permeability. However, the relation between ATPase activity and weight loss rate was linearly dependent with r=0.9784. Meanwhile, the results also implied that gas periodic stimulation had apparently strengthened microbial metabolism through increasing ATPase activity during gas double-dynamic solid state fermentation, resulting in motivating the production of cellulase by Trichoderma reesei YG3. Therefore, the increase of ATPase activity would be another crucial factor to strengthen fermentation process for cellulase production under gas double-dynamic solid state fermentation. Copyright © 2013 Elsevier Inc. All rights reserved.

Observation of Dynamical Super-Efimovian Expansion in a Unitary Fermi Gas

Science.gov (United States)

Deng, Shujin; Diao, Pengpeng; Li, Fang; Yu, Qianli; Yu, Shi; Wu, Haibin

2018-03-01

We report an observation of a dynamical super Efimovian expansion in a strongly interacting Fermi gas by engineering time dependent external harmonic trap frequencies. When the trap frequency is tailored as [1 /4 t2+1 /t2λ log2(t /t*)]1/2, where t* and λ are two controllable parameters, and the change is faster than a critical value, the expansion of such a quantum gas shows novel dynamics that share the same characteristics as the super Efimov effect. A clear double-log periodicity with discrete geometric scaling emerges for the cloud size in the expansion. The universality of such scaling dynamics is verified both in the noninteracting and in the unitarity limit of Fermi gas. Moreover, the measured energy scaling reveals that the potential and internal energy also show double-log periodicity with a π /2 phase difference, but the total energy is monotonically decreased. Observing super Efimovian evolution represents a paradigm in probing universal properties and allows us in a new way to study many-body nonequilibrium dynamics with experiments.

Comparison of 133Xe gas dynamic SPECT and thin-section CT in patients with pulmonary emphysema

International Nuclear Information System (INIS)

Takahashi, Kazue; Satoh, Katashi; Ohkawa, Motoomi

2001-01-01

We assessed 133 Xe gas dynamic single photon emission computed tomography (SPECT) by comparing washout axial images with thin-section CT (TSCT) in patients with pulmonary emphysema. Twenty-three patients were studied. All patients were diagnosed as having pulmonary emphysema on the basis of TSCT. We compared TSCT of upper, middle and lower lung fields with 133 Xe gas dynamic SPECT axial images at the corresponding levels during the 3 to 4 minutes of washout phase. If the degree of 133 Xe gas retention or TSCT finding of ventral and dorsal parts was not the same, the images were divided into two parts. A total of 174 lesions in 23 cases were examined, but 3 lesions having no retention of 133 Xe gas at equilibrium phase were excluded. The results showed that: there were 37 lesions (21.6%) with equivalent severity on both images; there were 42 lesions (24.5%) with more severity on 133 Xe gas dynamic SPECT than on TSCT; and there were 92 lesions (53.8%) with more severity on TSCT than on 133 Xe gas dynamic SPECT. The severity on 133 Xe gas dynamic SPECT and TSCT was not always compatible. One of the reasons for the variable 133 Xe gas retention even when the lesion had the same severity on TSCT, may be bronchial stricture which cannot be seen on TSCT. By comparison of axial images of 133 Xe gas dynamic SPECT with CT images, we could recognize the areas of 133 Xe gas retention in detail. Results suggest that 133 Xe gas dynamic SPECT can be useful to identify ventilation impairment in pulmonary emphysema. (author)

The real gas dynamics of the fluids of high specific heat

International Nuclear Information System (INIS)

Meier, G.E.A.

1987-01-01

The gas dynamics of real fluids show several new effects beyond the gas dynamics of ideal substances. Many of these effects rely on phase changes in the flow fields and can be explained with the help of more complicated thermal and caloric state equations of the real fluids. Complete adiabatic liquefaction and evaporation are possible for those substances whose specific heat exceeds a limit of about twenty gas constants. These fluids consisting of great molecules have so much internal energy storage capacity in their numerous vibrational degrees of freedom that the heat of evaporation can be supplied or also stored in the case of condensation. So liquefaction shock waves, which transform a gas completely or partly into a liquid, are possible. The shock front becomes thereby the surface of a liquid. Partial liquefaction with droplet condensation occurs in weaker shock waves. On the other hand a superheated liquid with high specific heat can be changed into a gas or mixture state in expansion waves or flows. (orig.)

Ablation plume dynamics in a background gas

DEFF Research Database (Denmark)

Amoruso, Salvatore; Schou, Jørgen; Lunney, James G.

2010-01-01

The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during the expa......The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during...... the expansion. The model also leads to an insightful treatment of the stopping behavior in dimensionless units for plumes and background gases of different atomic/molecular masses. The energetics of the plume dynamics can also be treated with this model. Experimental time-of-flight data of silver ions in a neon...... background gas show a fair agreement with predictions from the PM-model. Finally we discuss the validity of the model, if the work done by the pressure of the background gas is neglected....

Energy Law'88 Proceedings

International Nuclear Information System (INIS)

1988-01-01

This Seminar, divided into 10 topics, covered the legal, economic and trading aspects of oil, coal, natural gas and minerals, nuclear energy was examined from the viewpoint of present government policies, the future of this source of energy and of other sources. The papers presented at the Seminar are reproduced in the Proceedings. (NEA) [fr

5th international exhaust gas and particulate emissions forum. Proceedings; 5. Internationales Forum Abgas- und Partikelemissionen. Beitraege

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-12-11

The Proceedings of the 5th International Exhaust Gas and Particulate Emissions Forum contains 22 printed contributions as well as a CD-ROM. The titles of them are: (1) Diesel Emissions Control in the United States - 2010 and Beyond; (2) The MBE90 commercial vehicle engine for EPA '07 emissions regulations; (3) Concepts for engines and exhaust-gas cleaning systems for heavy duty trucks of the future; (4) HD Engine Technology for Near-Zero Emissions and Lowest Cost of Ownership; (5) (Partially-) Homogeneous Diesel Combustion; (6) Exhaust gas sensors for NOx storage catalysts and ammonia-SCR systems; (7) Sensors for modern exhaust gas after-treatment systems; (8) New reducing agents for low NOx-SCR Techno-logy; (9) Exhaust gas Aftertreatment on Lean Burn Gasoline Direct Injection Engines: The System of TWC and NOx-Storage Catalyst; (10) New Platinum/Palladium based catalyzed filter technologies for future passenger car applications; (11) Development of a Roadway Hydrocarbon Sorption Model and Characterization of a Novel PM Generator; (12) Requirements for current and future particulate measurement instrumentation from the point of view of the Physikalisch-Technische Bundesanstalt; (13) Standardized dilution conditions for gravimetric PM sampling - measures to assure results that correlate; (14) Particle Counting according PMP; (15) Future high-confidence measurement of diesel particulate emissions for approval and development; (16) New developments in optical instrumentation for exhaust gas; (17) Simultaneous Detection of Gaseous and Particulate Exhaust Components by Photoacoustic Spectroscopy; (18) Boundaries of modern exhaust gas instrumentation; (19) Raising quality and reducing application effort through efficient data input to the particulate filter load model for a EURO5 diesel car; (20) Stop-start operation of diesel engines - modified require-ment for exhaust gas after-treatment?; (21) Particulates emission with Biodiesel B30 impact on CSF management; (22

5th international exhaust gas and particulate emissions forum. Proceedings; 5. Internationales Forum Abgas- und Partikelemissionen. Beitraege

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-12-11

The Proceedings of the 5th International Exhaust Gas and Particulate Emissions Forum contains 22 printed contributions as well as a CD-ROM. The titles of them are: (1) Diesel Emissions Control in the United States - 2010 and Beyond; (2) The MBE90 commercial vehicle engine for EPA '07 emissions regulations; (3) Concepts for engines and exhaust-gas cleaning systems for heavy duty trucks of the future; (4) HD Engine Technology for Near-Zero Emissions and Lowest Cost of Ownership; (5) (Partially-) Homogeneous Diesel Combustion; (6) Exhaust gas sensors for NOx storage catalysts and ammonia-SCR systems; (7) Sensors for modern exhaust gas after-treatment systems; (8) New reducing agents for low NOx-SCR Techno-logy; (9) Exhaust gas Aftertreatment on Lean Burn Gasoline Direct Injection Engines: The System of TWC and NOx-Storage Catalyst; (10) New Platinum/Palladium based catalyzed filter technologies for future passenger car applications; (11) Development of a Roadway Hydrocarbon Sorption Model and Characterization of a Novel PM Generator; (12) Requirements for current and future particulate measurement instrumentation from the point of view of the Physikalisch-Technische Bundesanstalt; (13) Standardized dilution conditions for gravimetric PM sampling - measures to assure results that correlate; (14) Particle Counting according PMP; (15) Future high-confidence measurement of diesel particulate emissions for approval and development; (16) New developments in optical instrumentation for exhaust gas; (17) Simultaneous Detection of Gaseous and Particulate Exhaust Components by Photoacoustic Spectroscopy; (18) Boundaries of modern exhaust gas instrumentation; (19) Raising quality and reducing application effort through efficient data input to the particulate filter load model for a EURO5 diesel car; (20) Stop-start operation of diesel engines - modified require-ment for exhaust gas after-treatment?; (21) Particulates emission with Biodiesel B30 impact on CSF management; (22

Lateral Dynamics of Flexible Rotors Supported by Controllable Gas Bearings Theory & Experiment

DEFF Research Database (Denmark)

Pierart Vásquez, Fabián Gonzalo; Santos, Ilmar

2015-01-01

Active gas bearings might represent a mechatronic answer to the growing industrial need for high performance turbomachinery. In this framework, the paper gives a theoretical and experimental contribution to the improvement of lateral dynamics of rotating machines. The work aims at demonstrating...... theoretically as well as experimentally the feasibility of applying active lubrication to gas journal bearings. The operation principle is to generate active forces by regulating the radial injection of a compressible lubricant (gas) by means of piezoelectric actuators mounted on the back of the bearing sleeve....... The active control principle is built using eddy-current sensor signals to detect the lateral motion of the rotor. A feedback law is used to couple the lateral dynamics of a flexible rotor-bearing system with the pneumatic and dynamic characteristics of a piezoelectric actuated valve system. A proportional...

Lattice gas simulations of dynamical geometry in two dimensions.

Science.gov (United States)

Klales, Anna; Cianci, Donato; Needell, Zachary; Meyer, David A; Love, Peter J

2010-10-01

We present a hydrodynamic lattice gas model for two-dimensional flows on curved surfaces with dynamical geometry. This model is an extension to two dimensions of the dynamical geometry lattice gas model previously studied in one dimension. We expand upon a variation of the two-dimensional flat space Frisch-Hasslacher-Pomeau (FHP) model created by Frisch [Phys. Rev. Lett. 56, 1505 (1986)] and independently by Wolfram, and modified by Boghosian [Philos. Trans. R. Soc. London, Ser. A 360, 333 (2002)]. We define a hydrodynamic lattice gas model on an arbitrary triangulation whose flat space limit is the FHP model. Rules that change the geometry are constructed using the Pachner moves, which alter the triangulation but not the topology. We present results on the growth of the number of triangles as a function of time. Simulations show that the number of triangles grows with time as t(1/3), in agreement with a mean-field prediction. We also present preliminary results on the distribution of curvature for a typical triangulation in these simulations.

Gas dynamics models for an oscillating gaseous core fission reactor

Energy Technology Data Exchange (ETDEWEB)

Kuijper, J.C.; Dam, H. van; Hoogenboom, J.E. (Interuniversitair Reactor Inst., Delft (Netherlands))

1991-01-01

Two one-dimensional models are developed for the investigation of the gas dynamical behaviour of the fuel gas in a cylindrical gaseous core fission reactor. By numerical and analytical calculations, it is shown that, for the case where a direct energy extraction mechanism (such as magneto-hydrodynamics (MHD)) is not present, increasing density oscillations occur in the gas. Also an estimate is made of the attainable direct energy conversion efficiency, for the case where a direct energy extraction mechanism is present. (author).

Model-based dynamic control and optimization of gas networks

Energy Technology Data Exchange (ETDEWEB)

Hofsten, Kai

2001-07-01

This work contributes to the research on control, optimization and simulation of gas transmission systems to support the dispatch personnel at gas control centres for the decision makings in the daily operation of the natural gas transportation systems. Different control and optimization strategies have been studied. The focus is on the operation of long distance natural gas transportation systems. Stationary optimization in conjunction with linear model predictive control using state space models is proposed for supply security, the control of quality parameters and minimization of transportation costs for networks offering transportation services. The result from the stationary optimization together with a reformulation of a simplified fluid flow model formulates a linear dynamic optimization model. This model is used in a finite time control and state constrained linear model predictive controller. The deviation from the control and the state reference determined from the stationary optimization is penalized quadratically. Because of the time varying status of infrastructure, the control space is also generally time varying. When the average load is expected to change considerably, a new stationary optimization is performed, giving a new state and control reference together with a new dynamic model that is used for both optimization and state estimation. Another proposed control strategy is a control and output constrained nonlinear model predictive controller for the operation of gas transmission systems. Here, the objective is also the security of the supply, quality control and minimization of transportation costs. An output vector is defined, which together with a control vector are both penalized quadratically from their respective references in the objective function. The nonlinear model predictive controller can be combined with a stationary optimization. At each sampling instant, a non convex nonlinear programming problem is solved giving a local minimum

Modelling of gas-liquid reactors - stability and dynamic behaviour of gas-liquid mass transfer accompanied by irreversible reaction

NARCIS (Netherlands)

Elk, E.P. van; Borman, P.C.; Kuipers, J.A.M.; Versteeg, G.F.

1999-01-01

The dynamic behaviour and stability of single-phase reacting systems has been investigated thoroughly in the past and design rules for stable operation are available from literature. The dynamic behaviour of gas-liquid processes is considerably more complex and has received relatively little

Static and dynamic modelling of gas turbines in advanced cycles

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, Jan-Olof

1998-12-01

Gas turbines have been in operation for at least 50 years. The engine is used for propulsion of aircraft and high speed ships. It is used for power production in remote locations and for peak load and emergency situations. Gas turbines have been used in combined cycles for 20 to 30 years. Highly efficient power plants based on gas turbines are a competitive option for the power industry today. The thermal efficiency of the simple cycle gas turbine has increased due to higher turbine inlet temperatures and improved compressor and expander designs. Equally important are the improved cycles in which the gas turbine operates. One example is the combined cycle that uses steam for turbine cooling. Steam is extracted from the bottoming cycle, then used as airfoil coolant in a closed loop and returned to the bottoming cycle. The Evaporative Gas Turbine (EvGT), also known as the Humid Air Turbine (HAT), is another advanced cycle. A mixture of air and water vapour is used as working media. Air from the compressor outlet is humidified and then preheated in a recuperator prior to combustion. The static and dynamic performance is changed when the gas turbine is introduced in an evaporative cycle. The cycle is gaining in popularity, but so far it has not been demonstrated. A Swedish joint program to develop the cycle has been in operation since 1993. As part of the program, a small pilot plant is being erected at the Lund Institute of Technology (LTH). The plant is based on a 600 kW gas turbine, and demonstration of the EvGT cycle started autumn 1998 and will continue, in the present phase, for one year. This thesis presents static and dynamic models for traditional gas turbine components, such as, the compressor, combustor, expander and recuperator. A static model for the humidifier is presented, based on common knowledge for atmospheric humidification. All models were developed for the pilot plant at LTH with the objective to support evaluation of the process and individual

MERGER SIGNATURES IN THE DYNAMICS OF STAR-FORMING GAS

International Nuclear Information System (INIS)

Hung, Chao-Ling; Sanders, D. B.; Hayward, Christopher C.; Smith, Howard A.; Ashby, Matthew L. N.; Martínez-Galarza, Juan R.; Zezas, Andreas; Lanz, Lauranne

2016-01-01

The recent advent of integral field spectrographs and millimeter interferometers has revealed the internal dynamics of many hundreds of star-forming galaxies. Spatially resolved kinematics have been used to determine the dynamical status of star-forming galaxies with ambiguous morphologies, and constrain the importance of galaxy interactions during the assembly of galaxies. However, measuring the importance of interactions or galaxy merger rates requires knowledge of the systematics in kinematic diagnostics and the visible time with merger indicators. We analyze the dynamics of star-forming gas in a set of binary merger hydrodynamic simulations with stellar mass ratios of 1:1 and 1:4. We find that the evolution of kinematic asymmetries traced by star-forming gas mirrors morphological asymmetries derived from mock optical images, in which both merger indicators show the largest deviation from isolated disks during strong interaction phases. Based on a series of simulations with various initial disk orientations, orbital parameters, gas fractions, and mass ratios, we find that the merger signatures are visible for ∼0.2–0.4 Gyr with kinematic merger indicators but can be approximately twice as long for equal-mass mergers of massive gas-rich disk galaxies designed to be analogs of z ∼ 2–3 submillimeter galaxies. Merger signatures are most apparent after the second passage and before the black holes coalescence, but in some cases they persist up to several hundred Myr after coalescence. About 20%–60% of the simulated galaxies are not identified as mergers during the strong interaction phase, implying that galaxies undergoing violent merging process do not necessarily exhibit highly asymmetric kinematics in their star-forming gas. The lack of identifiable merger signatures in this population can lead to an underestimation of merger abundances in star-forming galaxies, and including them in samples of star-forming disks may bias the measurements of disk

Proceedings of the seventh EWM meeting, European Women in Mathematics

DEFF Research Database (Denmark)

The proceedings consist of a part concerning EWM and a mathematical part of mainly four series of papers. The series are within the following themes: Holomorphic Dynamics, Algebraic Geometry, Mathematical Physics and Moduli Spaces.......The proceedings consist of a part concerning EWM and a mathematical part of mainly four series of papers. The series are within the following themes: Holomorphic Dynamics, Algebraic Geometry, Mathematical Physics and Moduli Spaces....

High temperature gas cooled reactor technology development. Proceedings of a technical committee meeting

International Nuclear Information System (INIS)

1997-12-01

The successful introduction of an advanced nuclear power plant programme depends on many key elements. It must be economically competitive with alternative sources of energy, its technical development must assure operational dependability, the support of society requires that it be safe and environmentally acceptable, and it must meet the regulatory standards developed for its use and application. These factors interrelate with each other, and the ability to satisfy the established goals and criteria of all of these requirements is mandatory if a country or a specific industry is to proceed with a new, advanced nuclear power system. It was with the focus on commercializing the high temperature gas cooled reactor (HTGR) that the IAEA's International Working Group on Gas Cooled Reactors recommended this Technical Committee Meeting (TCM) on HTGR Technology Development. Over the past few years, many Member States have instituted a re-examination of their nuclear power policies and programmes. It has become evident that the only realistic way to introduce an advanced nuclear power programme in today's world is through international co-operation between countries. The sharing of expertise and technical facilities for the common development of the HTGR is the goal of the Member States comprising the IAEA's International Working Group on Gas Cooled Reactors. This meeting brought together key representatives and experts on the HTGR from the national organizations and industries of ten countries and the European Commission. The state electric utility of South Africa, Eskom, hosted this TCM in Johannesburg, from 13 to 15 November 1996. This TCM provided the opportunity to review the status of HTGR design and development activities, and especially to identify international co-operation which could be utilized to bring about the commercialization of the HTGR

Vacuum sealing with a spiral grooved gas dynamic seal

International Nuclear Information System (INIS)

Sawada, Tadashi

1979-01-01

Gas dynamic seals with rectangular spiral grooves are studied theoretically taking the effects of sidewalls of the grooves and the effects of gas compressibility into account, and slip boundary conditions are employed. The results are compared with the existing experimental data and the validity of the theory is confirmed over a wide pressure range except for the extremely low pressures. Suggestions are made regarding the choice of the geometrical dimensions, i.e., aspect ratio, helix angle, clearance parameter and groove width ratio. (author)

76 FR 52323 - Combined Notice of Filings; Filings Instituting Proceedings

Science.gov (United States)

2011-08-22

.... Applicants: Young Gas Storage Company, Ltd. Description: Young Gas Storage Company, Ltd. submits tariff..., but intervention is necessary to become a party to the proceeding. The filings are accessible in the.... More detailed information relating to filing requirements, interventions, protests, and service can be...

Dynamics and control of a gas-fired furnace

NARCIS (Netherlands)

Roffel, B.; Rijnsdorp, J.E.

1974-01-01

A non-linear model has been developed for a gas-fired furnace in which oil is heated. The model is applicable from minimum to maximum heat load of the furnace. The dynamics of the model have been compared to experimental results, which were obtained for a pilot-scale furnace. They are in good

Modeling and dynamic control simulation of unitary gas engine heat pump

International Nuclear Information System (INIS)

Zhao Yang; Haibo Zhao; Zheng Fang

2007-01-01

Based on the dynamic model of the gas engine heat pump (GEHP) system, an intelligent control simulation is presented to research the dynamic characteristics of the system in the heating operation. The GEHP system simulation model consists of eight models for its components including a natural gas engine, a compressor, a condenser, an expansion valve, an evaporator, a cylinder jacket heat exchanger, an exhaust gas heat exchanger and an auxiliary heater. The intelligent control model is composed of the prediction controller model and the combined controller model. The Runge-Kutta Fehlberg fourth-fifth order algorithms are used to solve the differential equations. The results show that the model is very effective in analyzing the effects of the control system, and the steady state accuracy of the intelligent control scheme is higher than that of the fuzzy controller

Nonlinear dynamics of a soliton gas: Modified Korteweg–de Vries equation framework

Energy Technology Data Exchange (ETDEWEB)

Shurgalina, E.G., E-mail: eshurgalina@mail.ru [Department of Nonlinear Geophysical Processes, Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Pelinovsky, E.N. [Department of Nonlinear Geophysical Processes, Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Department of Applied Mathematics, Nizhny Novgorod State Technical University, Nizhny Novgorod (Russian Federation)

2016-05-27

Dynamics of random multi-soliton fields within the framework of the modified Korteweg–de Vries equation is considered. Statistical characteristics of a soliton gas (distribution functions and moments) are calculated. It is demonstrated that the results sufficiently depend on the soliton gas properties, i.e., whether it is unipolar or bipolar. It is shown that the properties of a unipolar gas are qualitatively similar to the properties of a KdV gas [Dutykh and Pelinovsky (2014) [1

A System Dynamics Analysis of Investment, Technology and Policy that Affect Natural Gas Exploration and Exploitation in China

Directory of Open Access Journals (Sweden)

Jianzhong Xiao

2017-01-01

Full Text Available Natural gas has an increasing role in Chinese energy transformation. We present a system dynamics model of the natural gas industry in China. A new system dynamics model for natural gas companies based on reserve exploration and well construction as well as investment dynamics is proposed. The contribution of the paper is to analyze the influence of technology, investment and policy factors on the natural gas industry. We found that the dynamics of the main variables, including gas policy, cost of investment, accounting depreciation and exploitation technology, are sensitive to the sustainable development of resources. The simulations and results presented here will be helpful for government to reform policies, and for upstream companies to make decisions.

Interring Gas Dynamic Analysis of Piston in a Diesel Engine considering the Thermal Effect

Directory of Open Access Journals (Sweden)

Wanyou Li

2015-01-01

Full Text Available Understanding the interaction between ring dynamics and gas transport in ring pack systems is crucial and needs to be imperatively studied. The present work features detailed interring gas dynamics of piston ring pack behavior in internal combustion engines. The model is developed for a ring pack with four rings. The dynamics of ring pack are simulated. Due to the fact that small changes in geometry of the grooves and lands would have a significant impact on the interring gas dynamics, the thermal deformation of piston has been considered during the ring pack motion analysis in this study. In order to get the temperature distribution of piston head more quickly and accurately, an efficient method utilizing the concept of inverse heat conduction is presented. Moreover, a sensitive analysis based on the analysis of partial regression coefficients is presented to investigate the effect of groove parameters on blowby.

Price dynamics of natural gas and the regional methanol markets

International Nuclear Information System (INIS)

Masih, A. Mansur M.; Albinali, Khaled; DeMello, Lurion

2010-01-01

A 'methanol economy' based mainly on natural gas as a feedstock has a lot of potential to cope with the current and ongoing concerns for energy security along with the reduction of CO-2 emissions. It is, therefore, important to examine the price dynamics of methanol in order to ascertain whether the price of methanol is mainly natural-gas-cost driven or demand driven in the context of different regions. This paper is the first attempt to investigate the following: (1) is the natural gas price significantly related to the regional methanol prices in the Far East, United States and Europe? (2) who drives the regional methanol prices? The paper is motivated by the recent and growing debate on the lead-lag relationship between natural gas and methanol prices. Our findings, based on the most recently developed 'long-run structural modelling' and subject to the limitations of the study, tend to suggest: (1) natural gas price is cointegrated with the regional methanol prices, (2) our within-sample error-correction model results tend to indicate that natural gas was driving the methanol prices in Europe and the United States but not in the Far East. These results are consistent, during most of the period under review (1998.5-2007.3), with the surge in demand for methanol throughout the Far East, particularly in China, Taiwan and South Korea, which appears to have played a relatively more dominant role in the Far East compared to that in Europe and the United States within the framework of the dynamic interactions of input and product prices. However, during the post-sample forecast period as evidenced in our variance decompositions analysis, the emergence of natural gas as the main driver of methanol prices in all three continents is consistent with the recent surge in natural gas price fueled mainly, among others, by the strong hedging activities in the natural gas futures/options as well as refining tightness (similar to those that were happening in the crude oil markets

The articulation of Mexico into the dynamics of competition of the North American natural gas market

International Nuclear Information System (INIS)

Elizalde Baltierra, A.

2002-07-01

Deregulation is at the origin of the new dynamics of competition in the natural gas industry. The United States and Canada were the pioneer countries to suffer these changes. In fact, their natural gas markets today function in a very similar way: i) the private sector takes a place as large as possible, and ii)competition is developed within the three segments of the gas value, especially at the upstream level (emergence of hubs, spot and financial markets,...). In Mexico, its downstream gas activities (transportation, storage and distribution) were liberalized in 1995 in order to attract private investments and to develop the gas sector that has historically been operated under State control. Gas upstream operations remain reserved by the Constitution to the national oil company Petroleos Mexicanos (PEMEX). This thesis develops an evaluation framework of the articulation of Mexico into the dynamics of competition of the North American natural gas market, based on the structure-conduct-performance paradigm. In the first part, all North American's natural gas industries base conditions are analyzed. We examine in the second part, the deregulation and articulation of the dynamics of competition of the American and Canadian gas industries. Finally, in the third part we analyze the main elements of the articulation of Mexico into the dynamics of competition of United States and Canada's gas industries. Furthermore, we evaluate the impact of three of these elements (the economic growth, the electric power generation sector and eventually opening to private investments of gas upstream activities) on the adjustment of gas supply and demand in Mexico to the year 2020. (author)

Shale Gas in Poland: an Analysis of Tax Mechanisms and Dynamic Interactions

Directory of Open Access Journals (Sweden)

Dawid Walentek

2016-12-01

Full Text Available This is a preliminary research into possible taxation mechanisms for firms that will be operating in the shale gas industry in Poland and potential market interactions between the incumbents and the entrants. The study places focus on the level of welfare and it includes a static and a dynamic analysis. The result of the former is that the lump sum tax is the first best of all considered tax mechanisms for the Polish shale gas from the welfare perspective. The second best option for taxation is a combination of the current CIT rate and a windfall profit tax. In respect to the dynamic analysis, the results suggest that Gazprom can remain the market leader in Poland even if the shale gas producers start to operate, due to the sequential character of the competition in the Polish natural gas market. Counterintuitively, it will not come at the expenses of the consumers in Poland and it can bring potential welfare gains

On the Gas Dynamics of Inert-Gas-Assisted Laser Cutting of Steel Plate

Science.gov (United States)

Brandt, A. D.; Settles, G. S.; Scroggs, S. D.

1996-11-01

Laser beam cutting of sheet metal requires an assist gas to blow away the molten material. Since the assist-gas dynamics influences the quality and speed of the cut, the orientation of the gas nozzle with respect to the kerf is also expected to be important. A 1 kW cw CO2 laser with nitrogen assist gas was used to cut mild steel sheet of 1 to 4 mm thickness, using a sonic coaxial nozzle as a baseline. Off-axis nozzles were oriented from 20 deg to 60 deg from normal with exit Mach numbers from 1 to 2.4. Results showed maximum cutting speed at a 40 deg nozzle orientation. Shadowgrams of a geometrically-similar model kerf then revealed a separated shock wave-boundary layer interaction within the kerf for the (untilted) coaxial nozzle case. This was alleviated, resulting in a uniform supersonic flow throughout the kerf and consequent higher cutting speeds, by tilting the nozzle between 20 deg and 45 deg from the normal. This result did not depend upon the exit Mach number of the nozzle. (Research supported by NSF Grant DMI-9400119.)

Dynamic Studies with Radioisotopes in Medicine. Proceedings of the Symposium on Dynamics Studies with Radioisotopes in Clinical Medicine and Research

International Nuclear Information System (INIS)

1971-01-01

Observations on the temporal patterns of uptake, metabolism, clearance or excretion of administered radioactive materials form the basis of many important applications of radioisotopes in clinical medicine and research. Such applications include studies of organ function, of regional blood flow and of the turnover of various substances in the human body. Newly available radioisotopes, new instruments such as gamma came ras, new techniques and new methods of data analysis based on the use of analogue and digital computers are continually enlarging the scope of the applications. Progress in these matters was discussed at the Symposium on Dynamic Studies with Radioisotopes in Clinical Medicine and Research, organized by the lnternational Atomic Energy Agency and held in Rotterdam, The Netherlands, from 31 August to 4 September 1970. A total of 315 participants nominated by 39 countries and 4 international organizations attended, and the 70 papers presented cove r the theoretical aspects of dynamic studies, the development of techniques and instruments for such studies, and specific applications in studies of thyroid, renal, hepatic and splenic function, mineral metabolism, regional blood flow, and cardiac and pulmonary function. The proceedings include the full texts of all the papers presented together with the edited discussions. Invited review papers deal with the general aspects of the various main groups of applications covered. Many of the applications described have already reached the stage of routine use; others are still in the developmental stage. Of particular note in the latter connection are applications based on the quantitative analysis of scintillation camera data. The many papers presented on these topics and the ensuing discussions indicate the great interest now shown in this promising area of development. It is hoped that the proceedings will provide a valuable guide to the present status of the subject

A Dynamic Model of the Combined Electricity and Natural Gas Markets

DEFF Research Database (Denmark)

Jenkins, Sandra; Annaswamy, Anuradha M.; Hansen, Jacob

2015-01-01

With the shale gas revolution, coal retirements, environmental regulations, and increasing renewable energy resources, the interdependency of natural gas and electricity has grown significantly. Interdependency challenges, such as mismatched market schedules and disparate market operations, require...... quantitative modeling in order to garner insights into the effectiveness of various solutions. In this paper, a quantitative model with a dynamic market mechanism is proposed to evaluate the effects of the fuel uncertainty of natural gas-fired power plants on Social Welfare. The results of the model show...

Dynamical heterogeneity in a glass-forming ideal gas.

Science.gov (United States)

Charbonneau, Patrick; Das, Chinmay; Frenkel, Daan

2008-07-01

We conduct a numerical study of the dynamical behavior of a system of three-dimensional "crosses," particles that consist of three mutually perpendicular line segments of length sigma rigidly joined at their midpoints. In an earlier study [W. van Ketel, Phys. Rev. Lett. 94, 135703 (2005)] we showed that this model has the structural properties of an ideal gas, yet the dynamical properties of a strong glass former. In the present paper we report an extensive study of the dynamical heterogeneities that appear in this system in the regime where glassy behavior sets in. On the one hand, we find that the propensity of a particle to diffuse is determined by the structure of its local environment. The local density around mobile particles is significantly less than the average density, but there is little clustering of mobile particles, and the clusters observed tend to be small. On the other hand, dynamical susceptibility results indicate that a large dynamical length scale develops even at moderate densities. This suggests that propensity and other mobility measures are an incomplete measure of the dynamical length scales in this system.

The promising gas-dynamic schemes of vacuum deposition from the supersonic gas mixture flows

International Nuclear Information System (INIS)

Maltsev, R V; Rebrov, A K

2008-01-01

Gas jet deposition (GJD) becomes promising method of thin film and nanoparticle deposition. This paper is focused on elaboration of new methods of GJD based on different gas dynamic schemes of flow formation and interaction with substrate. Using direct statistical simulation method, the analysis was performed for: a) interaction of the jet from the sonic nozzle with a substrate; b) fan flow in the result of interaction of two opposite jets; c) convergent flow from the ring nozzle, directional to the axis; d) interaction of the jet after convergent flow with the substrate; e) fan flow in the result of interaction of two opposite jets after convergent expansion

Gas conference Paris 2013

International Nuclear Information System (INIS)

Anon.

2013-01-01

This special issue of Gaz d'Aujourd'hui journal contains the proceedings of the 2013 edition of the annual French gas conference. These proceedings comprise 7 talks, 5 round-tables and 9 workshops: 1 - Opening talk (H. Malherbe); 2 - Defending the natural gas position in the energy mix (G. Mestralet); 3 - The new youth of natural gas (P. Sauquet); 4 - Round-table No.1: the natural gas market perspectives; 5 - Round-table No.2: natural gas in France's energy transition; 6 - Answering the energy transition challenges (B. Lescoeur); 7 - Round-table No.3: towards an integrated European market in 2014?; 8 - Building up the European gas market (P. de Ladoucette); 9 - Workshop No.1: the big client's strategies in the gas market; 10 - Workshop No.2: the fuel gas perspectives in terrestrial mobility; 11 - Workshop No.3: gas innovations; 12 - The 2030 and 2050 strategy of the European Union policy (B. Devlin); 13 - Round-table No.4: Decentralized production and local development; 14 - Workshop No.4: Gas and maritime transport; 15 - Workshop No.5: bio-methane, vector of the energy transition; 16 - Workshop No.6: Evolution of the storage activity; 17 - Workshop No.7: Dwellings renovation and natural gas development; 18 - Workshop No.8: Is the target model of gas a reality?; 19 - Workshop No.9: Non-conventional gases in the world; 20 - Round-table No.5: Actors' strategy; 21 - Closing talk (J. Ferrier)

The role of the dynamic pressure in stationary heat conduction of a rarefied polyatomic gas

Energy Technology Data Exchange (ETDEWEB)

Arima, Takashi, E-mail: arima@kanagawa-u.ac.jp [Department of Mechanical Engineering, Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Barbera, Elvira, E-mail: ebarbera@unime.it [Department of Mathematics and Computer Science, University of Messina, V.le F. D' Alcontres 31, 98166 Messina (Italy); Brini, Francesca, E-mail: francesca.brini@unibo.it [Department of Mathematics, University of Bologna, via Saragozza 8, 40123 Bologna (Italy); Sugiyama, Masaru, E-mail: sugiyama@nitech.ac.jp [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

2014-07-18

The effect of the dynamic pressure (non-equilibrium pressure) on stationary heat conduction in a rarefied polyatomic gas at rest is elucidated by the theory of extended thermodynamics. It is shown that this effect is observable in a non-polytropic gas. Numerical studies are presented for a para-hydrogen gas as a typical example. - Highlights: • Heat transfer problem in polyatomic rarefied gases is studied in different domains. • Non-zero dynamic pressure is predicted in non-polytropic gases. • The effect of dynamic pressure can be observed indirectly in an experiment. • The case of para-hydrogen is analyzed as an example. • Navier–Stokes, Fourier, and Extended Thermodynamics predictions are compared.

Dynamic Gas Flow Effects on the ESD of Aerospace Vehicle Surfaces

Science.gov (United States)

Hogue, Michael D.; Kapat, Jayanta; Ahmed, Kareem; Cox, Rachel E.; Wilson, Jennifer G.; Calle, Luz M.; Mulligan, Jaysen

2016-01-01

The purpose of this work is to develop a dynamic version of Paschen's Law that takes into account the flow of ambient gas past aerospace vehicle surfaces. However, the classic Paschen's Law does not take into account the flow of gas of an aerospace vehicle, whose surfaces may be triboelectrically charged by dust or ice crystal impingement, traversing the atmosphere. The basic hypothesis of this work is that the number of electron-ion pairs created per unit distance by the electric field between the electrodes is mitigated by the electron-ion pairs removed per unit distance by the flow of gas. The revised Paschen equation must be a function of the mean velocity, v(sub xm), of the ambient gas and reduces to the classical version of Paschen's law when the gas mean velocity, v(sub xm) = 0. New formulations of Paschen's Law, taking into account Mach number and dynamic pressure, derived by the authors, will be discussed. These equations will be evaluated by wind tunnel experimentation later this year. Based on the results of this work, it is hoped that the safety of aerospace vehicles will be enhanced with a redefinition of electrostatic launch commit criteria. It is also possible that new products, such as new anti-static coatings, may be formulated from this data.

Proceedings of the 1999 CERI North American natural gas conference and Calgary gasexpo '99 : cresting the capacity wave

International Nuclear Information System (INIS)

1999-01-01

The basic trends in natural gas exploration, production, research and development were discussed. The significant impact that the dynamics of supply and demand has on the industry was also explained. The sessions at this conference focused on various aspects of the natural gas industry including the challenges from the retail energy market, U.S. gas supplies and the maturing Western Canada Sedimentary Basin. Other topics included advances in gas utilization and gas to liquids technology. The issue of climate change and the impact that the Kyoto Protocol will have on the industry was also discussed. One entire session was devoted to the challenges facing the industry with respect to pipelines and regulatory changes. refs., tabs., figs

A Computation Fluid Dynamic Model for Gas Lift Process Simulation in a Vertical Oil Well

Directory of Open Access Journals (Sweden)

Kadivar Arash

2017-03-01

Full Text Available Continuous gas-lift in a typical oil well was simulated using computational fluid dynamic (CFD technique. A multi fluid model based on the momentum transfer between liquid and gas bubbles was employed to simulate two-phase flow in a vertical pipe. The accuracy of the model was investigated through comparison of numerical predictions with experimental data. The model then was used to study the dynamic behaviour of the two-phase flow around injection point in details. The predictions by the model were compared with other empirical correlations, as well. To obtain an optimum condition of gas-lift, the influence of the effective parameters including the quantity of injected gas, tubing diameter and bubble size distribution were investigated. The results revealed that increasing tubing diameter, the injected gas rate and decreasing bubble diameter improve gas-lift performance.

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.

The effect of gas dynamics on semi-analytic modelling of cluster galaxies

Science.gov (United States)

Saro, A.; De Lucia, G.; Dolag, K.; Borgani, S.

2008-12-01

We study the degree to which non-radiative gas dynamics affect the merger histories of haloes along with subsequent predictions from a semi-analytic model (SAM) of galaxy formation. To this aim, we use a sample of dark matter only and non-radiative smooth particle hydrodynamics (SPH) simulations of four massive clusters. The presence of gas-dynamical processes (e.g. ram pressure from the hot intra-cluster atmosphere) makes haloes more fragile in the runs which include gas. This results in a 25 per cent decrease in the total number of subhaloes at z = 0. The impact on the galaxy population predicted by SAMs is complicated by the presence of `orphan' galaxies, i.e. galaxies whose parent substructures are reduced below the resolution limit of the simulation. In the model employed in our study, these galaxies survive (unaffected by the tidal stripping process) for a residual merging time that is computed using a variation of the Chandrasekhar formula. Due to ram-pressure stripping, haloes in gas simulations tend to be less massive than their counterparts in the dark matter simulations. The resulting merging times for satellite galaxies are then longer in these simulations. On the other hand, the presence of gas influences the orbits of haloes making them on average more circular and therefore reducing the estimated merging times with respect to the dark matter only simulation. This effect is particularly significant for the most massive satellites and is (at least in part) responsible for the fact that brightest cluster galaxies in runs with gas have stellar masses which are about 25 per cent larger than those obtained from dark matter only simulations. Our results show that gas dynamics has only a marginal impact on the statistical properties of the galaxy population, but that its impact on the orbits and merging times of haloes strongly influences the assembly of the most massive galaxies.

North American natural gas supply dynamics: A focus on U.S. supply

International Nuclear Information System (INIS)

George, R.

1999-01-01

This paper discusses US natural gas supply dynamics in the context of the North American gas marketplace. Supply fundamentals are examined, methodology is briefly presented, regional supply outlooks are discussed. Assumptions, drivers and issues are highlighted. The analysis and outlook indicate that the sizeable North American resource base can be economically developed to supply growing US natural gas requirements. The major incremental supply sources are likely to come from deepwater Gulf of Mexico, Rocky Mountain regions, onshore Texas and imports from Canada. Given this outlook, major business and investment opportunities exist for the gas upstream and midstream sectors despite some short-term challenges

Vectorization of a Monte Carlo simulation scheme for nonequilibrium gas dynamics

Science.gov (United States)

Boyd, Iain D.

1991-01-01

Significant improvement has been obtained in the numerical performance of a Monte Carlo scheme for the analysis of nonequilibrium gas dynamics through an implementation of the algorithm which takes advantage of vector hardware, as presently demonstrated through application to three different problems. These are (1) a 1D standing-shock wave; (2) the flow of an expanding gas through an axisymmetric nozzle; and (3) the hypersonic flow of Ar gas over a 3D wedge. Problem (3) is illustrative of the greatly increased number of molecules which the simulation may involve, thanks to improved algorithm performance.

Dynamics of a hot (T∼107 K) gas cloud with volume energy losses

International Nuclear Information System (INIS)

Suchkov, A.A.; Berman, V.G.; Mishurov, Yu.N.

1987-01-01

The dynamics of a hot (T=10 6 -5x10 7 K) gas cloud with volume energy losses is investigated by numerical integration of gas dynamics equations. The dynamics is governed by a spherically symmetric gravitational field of the cloud and additional ''hidden'' mass. The cloud mass is taken in the range M 0 =10 10 -10 12 M sun , its radius R 0 =50-200 kpc, the ''hidden'' mass M ν =10 11 -3x10 13 M sun . The results show that in such sytems a structure can develop in the form of a dense compact nucleus with a radius R s 0 , and an extended rarefied hot envelope with a radius R X ∼ R 0 . Among the models involved are those where the gas cloud is either entirely blown up or entirely collapses; in some models, after the phase of initial expansion, part of the gas mass returns back into the system to form a nucleus and an envelope, and the other part leaves the system. The results are discussed in connection with the formation and early evolution of galaxies, the history of star formation and chemical evolution of galaxies, the origin of hot gas in galaxies and clusters of galaxies. It is suggested that in the real history of galaxies, formation of the nucleus and envelope corresponds to formation of galactic stellar component and X-ray halo

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances

Energy Technology Data Exchange (ETDEWEB)

Faybishenko, B. (ed.)

1999-02-01

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

DYNAMICAL EVOLUTION OF AGN HOST GALAXIES-GAS IN/OUT-FLOW RATES IN SEVEN NUGA GALAXIES

International Nuclear Information System (INIS)

Haan, Sebastian; Schinnerer, Eva; Rix, Hans-Walter; Emsellem, Eric; GarcIa-Burillo, Santiago; Combes, Francoise; Mundell, Carole G.

2009-01-01

To examine the role of the host galaxy structure in fueling nuclear activity, we estimated gas flow rates from several kpc down to the inner few 10 pc for seven nearby spiral galaxies, selected from the NUclei of GAlaxies sample. We calculated gravitational torques from near-infrared images and determined gas in/out-flow rates as a function of radius and location within the galactic disks, based on high angular resolution interferometric observations of molecular (CO using Plateau de Bure interferometer) and atomic (H I using the Very Large Array) gas. The results are compared with kinematic evidence for radial gas flows and the dynamical state of the galaxies (via resonances) derived from several different methods. We show that gravitational torques are very efficient at transporting gas from the outer disk all the way into the galaxies centers at ∼100 pc; previously assumed dynamical barriers to gas transport, such as the corotation resonance of stellar bars, seem to be overcome by gravitational torque induced gas flows from other nonaxisymmetric structures. The resulting rates of gas mass inflow range from 0.01 to 50 M sun yr -1 and are larger for the galaxy center than for the outer disk. Our gas flow maps show the action of nested bars within larger bars for three galaxies. Noncircular streaming motions found in the kinematic maps are larger in the center than in the outer disk and appear to correlate only loosely with the in/out-flow rates as a function of radius. We demonstrate that spiral gas disks are very dynamic systems that undergo strong radial evolution on timescales of a few rotation periods (e.g., 5 x 10 8 yrs at a radius of 5 kpc), due to the effectiveness of gravitational torques in redistributing the cold galactic gas.

Bifurcation and nonlinear dynamic analysis of a flexible rotor supported by relative short gas journal bearings

International Nuclear Information System (INIS)

Wang, C.-C.; Jang, M.-J.; Yeh, Y.-L.

2007-01-01

This paper studies the bifurcation and nonlinear behaviors of a flexible rotor supported by relative short gas film bearings. A time-dependent mathematical model for gas journal bearings is presented. The finite difference method with successive over relation method is employed to solve the Reynolds' equation. The system state trajectory, Poincare maps, power spectra, and bifurcation diagrams are used to analyze the dynamic behavior of the rotor and journal center in the horizontal and vertical directions under different operating conditions. The analysis reveals a complex dynamic behavior comprising periodic and subharmonic response of the rotor and journal center. This paper shows how the dynamic behavior of this type of system varies with changes in rotor mass and rotational velocity. The results of this study contribute to a further understanding of the nonlinear dynamics of gas film rotor-bearing systems

Studies on fuels with low fission gas release. Proceedings of a technical committee meeting

International Nuclear Information System (INIS)

1997-10-01

For more than a decade, the IAEA has organized various specialists meetings to discuss advances in nuclear fuel technology for non-water cooled reactors. In order to review progress in research and development of fuels with low fission gas release for light water reactors, fast reactors and research reactors, an IAEA Technical Committee meeting was organized in October 1996. At the invitation of the Government of the Russian Federation, the meeting was held in Moscow. Experts from seven Member States and one international organization participated. The objective of the meeting was to exchange topical information on such fuels, to evaluate their advantages and drawbacks, and to explore their commercial utilization. The present volume contains the full text of the sixteen papers presented at the meeting. The information compiled in these proceedings should be useful for engineers, scientists and managers from nuclear fuel development organizations, fuel fabrication plants, utilities and regulatory bodies who are involved in the analysis of fuel behaviour under normal and accident conditions. Refs, figs, tabs

Study on the dynamics of charged particles in a rarefied gas of thermonuclear reactor injector

International Nuclear Information System (INIS)

Afanas'ev, P.N.; Svistunov, Yu.A.; Sidorov, V.P.; Udovichenko, S.Yu.

1987-01-01

The motion of an ion beam directly beyond the source is considered in the assumption of homogeneous density of rarefied gas along the injector. Using numerical simulation the dynamics of fast particles in plasma electric field, created by the beam as a result of gas neutral atom ionization, is investigated. It is shown that stationary ambipolar electric field of ''plasma lens'' can affect considerably the beam transverse dynamics

The dynamics of the world gas trade

International Nuclear Information System (INIS)

Chabrelie, M.F.

2003-01-01

The steadily growing distances between the world's gas rich regions and consumer zones foreshadow a powerful expansion of the international trade, at an annual rate of around 3.5% by 2020. Flows could then account for about 32% of marketed production. Trade by LNG tanker is very likely to emerge as the winner of this dynamic, with the flexibility it procures exploited to adjust supply to the demand of a more global market. This is today's gamble of an industry which, driven by technological improvements and market potential, is investing massively in new infrastructures

High resolution kinetic beam schemes in generalized coordinates for ideal quantum gas dynamics

International Nuclear Information System (INIS)

Shi, Yu-Hsin; Huang, J.C.; Yang, J.Y.

2007-01-01

A class of high resolution kinetic beam schemes in multiple space dimensions in general coordinates system for the ideal quantum gas is presented for the computation of quantum gas dynamical flows. The kinetic Boltzmann equation approach is adopted and the local equilibrium quantum statistics distribution is assumed. High-order accurate methods using essentially non-oscillatory interpolation concept are constructed. Computations of shock wave diffraction by a circular cylinder in an ideal quantum gas are conducted to illustrate the present method. The present method provides a viable means to explore various practical ideal quantum gas flows

Dynamical evolution of stars and gas of young embedded stellar sub-clusters

Science.gov (United States)

Sills, Alison; Rieder, Steven; Scora, Jennifer; McCloskey, Jessica; Jaffa, Sarah

2018-03-01

We present simulations of the dynamical evolution of young embedded star clusters. Our initial conditions are directly derived from X-ray, infrared, and radio observations of local systems, and our models evolve both gas and stars simultaneously. Our regions begin with both clustered and extended distributions of stars, and a gas distribution which can include a filamentary structure in addition to gas surrounding the stellar subclusters. We find that the regions become spherical, monolithic, and smooth quite quickly, and that the dynamical evolution is dominated by the gravitational interactions between the stars. In the absence of stellar feedback, the gas moves gently out of the centre of our regions but does not have a significant impact on the motions of the stars at the earliest stages of cluster formation. Our models at later times are consistent with observations of similar regions in the local neighbourhood. We conclude that the evolution of young proto-star clusters is relatively insensitive to reasonable choices of initial conditions. Models with more realism, such as an initial population of binary and multiple stars and ongoing star formation, are the next step needed to confirm these findings.

High temperature gas dynamics an introduction for physicists and engineers

CERN Document Server

Bose, Tarit K

2014-01-01

High Temperature Gas Dynamics is a primer for scientists, engineers, and students who would like to have a basic understanding of the physics and the behavior of high-temperature gases. It is a valuable tool for astrophysicists as well. The first chapters treat the basic principles of quantum and statistical mechanics and how to derive thermophysical properties from them. Special topics are included that are rarely found in other textbooks, such as the thermophysical and transport properties of multi-temperature gases and a novel method to compute radiative transfer. Furthermore, collision processes between different particles are discussed. Separate chapters deal with the production of high-temperature gases and with electrical emission in plasmas, as well as related diagnostic techniques.This new edition adds over 100 pages and includes the following updates: several sections on radiative properties of high temperature gases and various radiation models, a section on shocks in magneto-gas-dynamics, a sectio...

THE DETERMINATION THE POLLUTION EMISSIONS OF SO2, NOX, CO, CO2 AND O2 FROM THE CHANNELS OF BURNT GAS ON BOILER OF 420 T/H - STEAM, IN THE SIGHT APPLICATION PROCEEDING TO REDUCE OF THESE

Directory of Open Access Journals (Sweden)

Valentin Nedeff

2007-03-01

Full Text Available The work present the results obtained after dynamic analyze the pollution emissions of SO2, NOx, CO, CO2 and O2 on evacuation channels of burnt gas on boiler of 420 t/h steam, having right the basic combustible the lignite, and auxiliary combustible the fuel oil and the natural gas. The values of pollution emission was analyze beside the admissible maxims values required by European legislation for Romania in the year 2005. The conclusion elaborated it adverted to: the values of oxides azoth, carry they frame in the limits provide in Environmental Authorization, under 60 mg/Nmc on 6% oxygen, the concentration values of SO2 which was bigger in report with one authorized comprised between 3500-3900 mg/Nmc confronted by 3400 mg/Nm. For integration in the foresee Government Decision 541/2003 aren't sufficient just proceeding of below reduce SO2, must take and another measures such as: get the fuel with quantity of sulphur 0.5% and with a content of ash below 35%.

Flow-pattern identification and nonlinear dynamics of gas-liquid two-phase flow in complex networks.

Science.gov (United States)

Gao, Zhongke; Jin, Ningde

2009-06-01

The identification of flow pattern is a basic and important issue in multiphase systems. Because of the complexity of phase interaction in gas-liquid two-phase flow, it is difficult to discern its flow pattern objectively. In this paper, we make a systematic study on the vertical upward gas-liquid two-phase flow using complex network. Three unique network construction methods are proposed to build three types of networks, i.e., flow pattern complex network (FPCN), fluid dynamic complex network (FDCN), and fluid structure complex network (FSCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K -mean clustering, useful and interesting results are found which can be used for identifying five vertical upward gas-liquid two-phase flow patterns. To investigate the dynamic characteristics of gas-liquid two-phase flow, we construct 50 FDCNs under different flow conditions, and find that the power-law exponent and the network information entropy, which are sensitive to the flow pattern transition, can both characterize the nonlinear dynamics of gas-liquid two-phase flow. Furthermore, we construct FSCN and demonstrate how network statistic can be used to reveal the fluid structure of gas-liquid two-phase flow. In this paper, from a different perspective, we not only introduce complex network theory to the study of gas-liquid two-phase flow but also indicate that complex network may be a powerful tool for exploring nonlinear time series in practice.

Gas phase collision dynamics by means of pulse-radiolysis methods

International Nuclear Information System (INIS)

Hatano, Yoshihiko

1989-01-01

After a brief survey of recent advances in gas-phase collision dynamics studies using pulse radiolysis methods, the following two topics in our research programs are presented with emphasis on the superior advantages of the pulse radiolysis methods over the various methods of gas-phase collision dynamics, such as beam methods, swarm methods and flow methods. One of the topics is electron attachment to van der Waals molecules. The attachment rates of thermal electrons to O 2 and other molecules in dense gases have been measured in wide ranges of both gas temperatures and pressures, from which experimental evidence has been obtained for electron attachment to van der Waals molecules. The results have been compared with theories and discussed in terms of the effect of van der Waals interaction on the electron attachment resonance. The obtained conclusions have been related with investigations of electron attachment, solvation and localization in the condensed phase. The other is Penning ionization and its related processes. The rate constants for the de-excitation of He(2 1 P), He(2 3 S), Ne( 3 P 0 ), Ne( 3 P 1 ), Ne( 3 P 2 ), Ar( 1 P 1 ), Ar( 3 P 1 ), by atoms and molecules have been measured in the temperature range from 100 to 300 K, thus obtaining the collisional energy dependence of the de-excitation cross sections. The results are compared in detail with theories classified according to the excited rare gas atoms in the metastable and resonance states. (author)

Application of advanced data reduction methods to gas turbine dynamic analysis

International Nuclear Information System (INIS)

Juhl, P.B.

1978-01-01

This paper discusses the application of advanced data reduction methods to the evaluation of dynamic data from gas turbines and turbine components. The use of the Fast Fourier Transform and of real-time spectrum analyzers is discussed. The use of power spectral density and probability density functions for analyzing random data is discussed. Examples of the application of these modern techniques to gas turbine testing are presented. The use of the computer to automate the data reduction procedures is discussed. (orig.) [de

Exhaust Gas Temperature Measurements in Diagnostics of Turbocharged Marine Internal Combustion Engines Part II Dynamic Measurements

Directory of Open Access Journals (Sweden)

Korczewski Zbigniew

2016-01-01

Full Text Available The second part of the article describes the technology of marine engine diagnostics making use of dynamic measurements of the exhaust gas temperature. Little-known achievements of Prof. S. Rutkowski of the Naval College in Gdynia (now: Polish Naval Academy in this area are presented. A novel approach is proposed which consists in the use of the measured exhaust gas temperature dynamics for qualitative and quantitative assessment of the enthalpy flux of successive pressure pulses of the exhaust gas supplying the marine engine turbocompressor. General design assumptions are presented for the measuring and diagnostic system which makes use of a sheathed thermocouple installed in the engine exhaust gas manifold. The corrected thermal inertia of the thermocouple enables to reproduce a real time-history of exhaust gas temperature changes.

A gas dynamic and thermochemical model of steam/sodium microleak phenomena

International Nuclear Information System (INIS)

Perkins, R.; Airey, R.; Daniels, L.C.

1985-06-01

Conflicting findings have been reported by 3 UK laboratories for the blockage or rapid escalation of steam/sodium microleaks. In an earlier paper it was shown that this discrepancy could be resolved through the influence on the steam flow of the geometry of the leak paths; the geometry being dependent upon the method of manufacture. The application of gas dynamics and thermochemical methods could account for the rapid escalation of some leaks in terms of the presence of shock waves in the gas flow within the leak path. In this paper the gas dynamic and thermochemical theories are re-stated and a series of leak experiments conducted to test the validity of the theory is described. The theory predicts that for some leaks of variable area of cross-section the blockage/escalation behaviour is determined by small changes in the sodium-side pressure; this effect was found and is discussed as a validation of the theory. Other aspects of leak phenomena are discussed and conclusions are drawn with emphasis on implications for further programmes of leak study and for leaks in LMFBR steam generators in service. (author)

Dynamic gas flow during plasma operation in TMX-U

International Nuclear Information System (INIS)

Pickles, W.L.; Carter, M.R.; Clower, C.A.; Drake, R.P.; Hunt, A.L.; Simonen, T.C.; Turner, W.C.

1982-01-01

Control of the neutral density outside of the plasma radius is essential for proper operation of the various plasma configurations in TMX-U. TMX-U excess-beam, stream-gun, gas-box, and beam-reflux gases are pumped internally in regions defined by 73 0 Ti-gettered liners and warm Ti-gettered plasma liners. The array of fast and slow ion gauges - a large TMX-U diagnostic - has been used to measure the dynamic pressure in many of the liner-defined regions on three time scales. The natural divertor action, or plasma pump effect, of mirror plasmas has been measured using the ion gauge diagnostics on a fast time scale during operation of TMX-U with ECRH start-up. Routine operation of TMX-U is enhanced by the ability to verify the effectiveness of gettering and to locate leaks using pressure data collected on the two slow time scales. A computer code, DYNAVAC 6, which treats TMX-U as a set of conductance-coupled regions with pumping and sources in each region, has been used to successfully model the overall gas dynamics during all phases of TMX-U operation

Dynamic design of gas sorption J-T refrigerator

International Nuclear Information System (INIS)

Chan, C.K.

1986-01-01

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts and is desirable for longterm sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed using a dynamic model, which is described here. The model includes the kinetics of the compressors and the heat switches, the heat transfer of the pre-coolers and the heat exchangers, the on/off ratio of the check valves, and the impedance of the J-T valve. The cooling power, the cycle time, and the operating conditions were obtained in terms of the power input, the heat sink temperature, and the J-T impedance

Dynamic design of gas sorption J-T refrigerator

Science.gov (United States)

Chan, C. K.

1986-01-01

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts is desirable for long-term sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed using a dynamic model, which is described here. The model includes the kinetics of the compressors and the heat switches, the heat transfer of the pre-coolers and the heat exchangers, the on/off ratio of the check valves, and the impedance of the J-T valve. The cooling power, the cycle time, and the operating conditions were obtained in terms of the power input, the heat sink temperature, and the J-T impedance.

Dynamic modeling of gas turbines in integrated gasification fuel cell systems

Science.gov (United States)

Maclay, James Davenport

2009-12-01

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems for use in integrated gasification fuel cell (IGFC) systems operating on coal will stretch existing fossil fuel reserves, generate power with less environmental impact, while having a cost of electricity advantage over most competing technologies. However, the dynamic performance of a SOFC-GT in IGFC applications has not been previously studied in detail. Of particular importance is how the turbo-machinery will be designed, controlled and operated in such applications; this is the focus of the current work. Perturbation and dynamic response analyses using numerical SimulinkRTM models indicate that compressor surge is the predominant concern for safe dynamic turbo-machinery operation while shaft over-speed and excessive turbine inlet temperatures are secondary concerns. Fuel cell temperature gradients and anode-cathode differential pressures were found to be the greatest concerns for safe dynamic fuel cell operation. Two control strategies were compared, that of constant gas turbine shaft speed and constant fuel cell temperature, utilizing a variable speed gas turbine. Neither control strategy could eliminate all vulnerabilities during dynamic operation. Constant fuel cell temperature control ensures safe fuel cell operation, while constant speed control does not. However, compressor surge is more likely with constant fuel cell temperature control than with constant speed control. Design strategies that provide greater surge margin while utilizing constant fuel cell temperature control include increasing turbine design mass flow and decreasing turbine design inlet pressure, increasing compressor design pressure ratio and decreasing compressor design mass flow, decreasing plenum volume, decreasing shaft moment of inertia, decreasing fuel cell pressure drop, maintaining constant compressor inlet air temperature. However, these strategies in some cases incur an efficiency penalty. A broad comparison of cycles

Seasonal Trace Gas Dynamics on Minerotrophic Fen Peatlands in NE-Germany

Science.gov (United States)

Giebels, Michael; Beyer, Madlen; Augustin, Jürgen; Minke, Merten; Juszczak, Radoszlav; Serba, Tomasz

2010-05-01

In Germany more than 99 % of fens have lost their carbon and nutrient sink function due to heavy drainage and agricultural land use especially during the last decades and thus resulted in compression and heavy peat loss (CHARMAN 2002; JOOSTEN & CLARKE 2002; SUCCOW & JOOSTEN 2001; AUGUSTIN et al. 1996; KUNTZE 1993). Therefore fen peatlands play an important part (4-5 %) in the national anthropogenic trace gas budget. But only a small part of drained and agricultural used fens in NE Germany can be restored. Knowledge of the influence of land use to trace gas exchange is important for mitigation of the climate impact of the anthropogenic peatland use. We study carbon exchanges of several fen peatland use areas between soil and atmosphere at different sites in NE-Germany. Our research covers peatlands of supposed strongly climate forcing land use (cornfield and intensive pasture) and of probably less forcing, alternative types (meadow and extensive pasture) as well as rewetted (formerly drained) areas and near-natural sites like a low-degraded fen and a wetted alder woodland. We measured trace gas fluxes with manual and automatic chambers in periodic routines since spring 2007. The used chamber technique bases on DROESLER (2005). In total we now do research at 22 sites situated in 5 different locations covering agricultural, varying states of rewetted and near-natural treatments. We present results of at least 2 years of measurements and show significant differences in their annual trace gas balances depending on the genesis of the observed sites and the seasonal dynamics. Crosswise comparison of different site treatments combined with the seasonal environmental observations give good hints for the identification of main flux driving parameters. That is that a reduced intensity in land use as a supposed mitigating treatment did not show the expected effect, though a normal meadow treatment surprisingly resulted in the lowest balances in both years. For implementing a

Proceedings of the international workshop on hadron facility technology

Energy Technology Data Exchange (ETDEWEB)

Thiessen, H.A. (comp.)

1987-12-01

The conference included papers on facility plans, beam dynamics, accelerator hardware, and experimental facilities. Individual abstracts were prepared for 43 papers in the conference proceedings. (LEW)

Conference Proceedings: Structuring oil and gas property transactions

International Nuclear Information System (INIS)

1999-01-01

The 12 presentations at this conference dealt with issues concerning the legal aspects of oil and gas property transaction agreements. Several issues regarding sales and purchase negotiations of oil and gas property are reviewed and some of the basic principles of contract law are explained. Advantages, disadvantages and opportunities of structuring oil and gas property acquisitions, as well as their tax consequences are also identified. The issue of risk assessment regarding environmental consequences and how public concerns regarding the state of the environment has had an impact on oil and gas transactions, is addressed. Interest in this topic stems from the fact that improved enforcement of existing laws regarding the environment can potentially make purchasers liable for significant costs associated with remediation or clean-up of contaminated properties. refs., tabs., figs

MULTI-CRITERIA EVALUATION OF THE EXPANSION OF NATURAL GAS DISTRIBUTION NETWORK BY THE URBAN DYNAMICS

Directory of Open Access Journals (Sweden)

Vanessa M. Massara

2010-01-01

Full Text Available The objective of this work is to analyze the expansion of the infrastructure of natural gas distribution, identifying priorities from large metropolis using the energy planning based on urban design tools like urban dynamics and techniques like AHP (analytic hierarchy process. The methodology proposed uses matrices considering the relations between the concept of urban dynamics, quality of life and the possibilities of natural gas displacing other energy forms. The matrices are made up of information about social and urban development, costs of establishing the infrastructure and projections of the consumption potential in various sectors. Relating the consumption to urban development parameters and the real estate future of the areas in study, the methodology allows indicating for each district, the viability of implementing a gas network. As conclusion, the model presents the integration between the cities profile and the natural gas use, by means of a growth natural gas on districts of São Paulo City as a specific case study.

A new technique in constructing closed-form solutions for nonlinear PDEs appearing in fluid mechanics and gas dynamics

Directory of Open Access Journals (Sweden)

Panayotounakos D. E.

1996-01-01

Full Text Available We develop a new unique technique in constructing closed-form solutions for several nonlinear partial differential systems appearing in fluid mechanics and gas dynamics. The obtained solutions include fewer arbitrary functions than needed for general solutions, fact that permits us to specify them according to the initial state, or the geometry, of each specific problem under consideration. In order to apply the before mentioned technique we construct closed-form solutions concerning the gas-dynamic equations with constant pressure, the dynamic equations of an ideal gas in isentropic flow, and the two-dimensional incompressible boundary layer flow.

Dynamic Optimal Energy Flow in the Integrated Natural Gas and Electrical Power Systems

DEFF Research Database (Denmark)

Fang, Jiakun; Zeng, Qing; Ai, Xiaomeng

2018-01-01

. Simulation on the test case illustrates the success of the modelling and the beneficial roles of the power-to-gas are analyzed. The proposed model can be used in the decision support for both planning and operation of the coordinated natural gas and electrical power systems.......This work focuses on the optimal operation of the integrated gas and electrical power system with bi-directional energy conversion. Considering the different response times of the gas and power systems, the transient gas flow and steady- state power flow are combined to formulate the dynamic...... optimal energy flow in the integrated gas and power systems. With proper assumptions and simplifications, the problem is transformed into a single stage linear programming. And only a single stage linear programming is needed to obtain the optimal operation strategy for both gas and power systems...

BASIN-CENTERED GAS SYSTEMS OF THE U.S.

Energy Technology Data Exchange (ETDEWEB)

Marin A. Popov; Vito F. Nuccio; Thaddeus S. Dyman; Timothy A. Gognat; Ronald C. Johnson; James W. Schmoker; Michael S. Wilson; Charles Bartberger

2000-11-01

The USGS is re-evaluating the resource potential of basin-centered gas accumulations in the U.S. because of changing perceptions of the geology of these accumulations, and the availability of new data since the USGS 1995 National Assessment of United States oil and gas resources (Gautier et al., 1996). To attain these objectives, this project used knowledge of basin-centered gas systems and procedures such as stratigraphic analysis, organic geochemistry, modeling of basin thermal dynamics, reservoir characterization, and pressure analysis. This project proceeded in two phases which had the following objectives: Phase I (4/1998 through 5/1999): Identify and describe the geologic and geographic distribution of potential basin-centered gas systems, and Phase II (6/1999 through 11/2000): For selected systems, estimate the location of those basin-centered gas resources that are likely to be produced over the next 30 years. In Phase I, we characterize thirty-three (33) potential basin-centered gas systems (or accumulations) based on information published in the literature or acquired from internal computerized well and reservoir data files. These newly defined potential accumulations vary from low to high risk and may or may not survive the rigorous geologic scrutiny leading towards full assessment by the USGS. For logistical reasons, not all basins received the level of detail desired or required.

Hybrid Approximate Dynamic Programming Approach for Dynamic Optimal Energy Flow in the Integrated Gas and Power Systems

DEFF Research Database (Denmark)

Shuai, Hang; Ai, Xiaomeng; Wen, Jinyu

2017-01-01

This paper proposes a hybrid approximate dynamic programming (ADP) approach for the multiple time-period optimal power flow in integrated gas and power systems. ADP successively solves Bellman's equation to make decisions according to the current state of the system. So, the updated near future...

Comparison of molecular dynamics and kinetic modeling of gas-surface interactions

NARCIS (Netherlands)

Frezzotti, A.; Gaastra - Nedea, S.V.; Markvoort, A.J.; Spijker, P.; Gibelli, L.

2008-01-01

The interaction of a dilute monatomic gas with a solid surface is studied byMolecular Dynamics (MD) simulations and by numerical solutions of a recently proposed kinetic model. Following previous investigations, the heat transport between parallel walls and Couette flow have been adopted as test

Dynamics of elementary processes in the gas phase O2 and CO

International Nuclear Information System (INIS)

Bacchus-Montabonel, M.C.; Tergiman, Y.S.; Vaeck, N.; Baloitcha, E.; Desouter-Lecomte, M.

2002-01-01

Complex reaction mechanisms are involved in the radiation of biomolecules, their dynamics may proceed by a series of elementary processes, induced often by a fast reaction step, followed by relaxation or reorganization of the molecular system. The time-dependent wave packet method tested on the Si 4+ + He system, provides a clear and physical insight into the dynamics of theses process. Photodissociation experiments were performed, in particular the dissociation of bromoacetylchloride Br-CH 2 -COCl, to study the competitive dissociation of C-Cl and C-Br bonds. The dissociation leaded preferentially to C- Cl breaking, although the C-Br bond is thermodynamically weaker. This result is in disagreement with statistical theories, as the branching ratio depends not only on the relative height of the corresponding barriers, but also on non-adiabatic transitions arising from interactions between the different excited states. The effects depends on the distance between the C=O and C-X chromophores and on the conforming molecule. (nevyjel)

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

Quench dynamics of the interacting Bose gas in one dimension.

Science.gov (United States)

Iyer, Deepak; Andrei, Natan

2012-09-14

We obtain an exact expression for the time evolution of the interacting Bose gas following a quench from a generic initial state using the Yudson representation for integrable systems. We study the time evolution of the density and noise correlation for a small number of bosons and their asymptotic behavior for any number. We show that for any value of the coupling, as long as it is repulsive, the system asymptotes towards a strongly repulsive gas, while for any value of an attractive coupling the long time behavior is dominated by the maximal bound state. This occurs independently of the initial state and can be viewed as an emerging "dynamic universality."

Diatomic infrared gas-dynamic laser

International Nuclear Information System (INIS)

Mckenzie, R.L.

1971-01-01

A laser is provided which utilizes the infrared vibration rotation transitions of a diatomic gas such as carbon monoxide. The laser action is produced by an active diatomic gas such as carbon monoxide mixed with a vibrationally resonant pumping gas such as nitrogen. In addition, a noble gas such as argon may be employed as a third gas in the mixture. The gas mixture contains from 1 to 80 vol percent of the active gas based on the pumping gas, and the third gas, if used, can constitute up to 90 percent of the total gas volume. A number of significantly different wavelengths can be produced by the laser. A single laser may contain several optical resonators at different locations, so that the desired wave length can be selected at will

Exploratory investigation of the HIPPO gas-jet target fluid dynamic properties

Energy Technology Data Exchange (ETDEWEB)

Meisel, Zach, E-mail: zmeisel@nd.edu [Department of Physics, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Shi, Ke; Jemcov, Aleksandar [Hessert Laboratory for Aerospace Research, Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556 (United States); Couder, Manoel [Department of Physics, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States)

2016-08-21

In order to optimize the performance of gas-jet targets for future nuclear reaction measurements, a detailed understanding of the dependence of the gas-jet properties on experiment design parameters is required. Common methods of gas-jet characterization rely on measuring the effective thickness using nuclear elastic scattering and energy loss techniques; however, these tests are time intensive and limit the range of design modifications which can be explored to improve the properties of the jet as a nuclear reaction target. Thus, a more rapid jet-characterization method is desired. We performed the first steps towards characterizing the gas-jet density distribution of the HIPPO gas-jet target at the University of Notre Dame's Nuclear Science Laboratory by reproducing results from {sup 20}Ne(α,α){sup 20}Ne elastic scattering measurements with computational fluid dynamics (CFD) simulations performed with the state-of-the-art CFD software ANSYS Fluent. We find a strong sensitivity to experimental design parameters of the gas-jet target, such as the jet nozzle geometry and ambient pressure of the target chamber. We argue that improved predictive power will require moving to three-dimensional simulations and additional benchmarking with experimental data.

FIRST OPERATING RESULTS OF A DYNAMIC GAS BEARING TURBINE IN AN INDUSTRIAL HYDROGEN LIQUEFIER

International Nuclear Information System (INIS)

Bischoff, S.; Decker, L.

2010-01-01

Hydrogen has been brought into focus of industry and public since fossil fuels are depleting and costs are increasing dramatically. Beside these issues new high-tech processes in the industry are in need for hydrogen at ultra pure quality. To achieve these requirements and for efficient transportation, hydrogen is liquefied in industrial plants. Linde Gas has commissioned a new 5.5 TPD Hydrogen liquefier in Leuna, Germany, which has been engineered and supplied by Linde Kryotechnik. One of the four expansion turbines installed in the liquefaction process is equipped with dynamic gas bearings. Several design features and operational characteristics of this application will be discussed. The presentation will include results of efficiency and operational reliability that have been determined from performance tests. The advantages of the Linde dynamic gas bearing turbine for future use in hydrogen liquefaction plants will be shown.

Lattice gas simulations of dynamical geometry in one dimension.

Science.gov (United States)

Love, Peter J; Boghosian, Bruce M; Meyer, David A

2004-08-15

We present numerical results obtained using a lattice gas model with dynamical geometry. The (irreversible) macroscopic behaviour of the geometry (size) of the lattice is discussed in terms of a simple scaling theory and obtained numerically. The emergence of irreversible behaviour from the reversible microscopic lattice gas rules is discussed in terms of the constraint that the macroscopic evolution be reproducible. The average size of the lattice exhibits power-law growth with exponent at late times. The deviation of the macroscopic behaviour from reproducibility for particular initial conditions ('rogue states') is investigated as a function of system size. The number of such 'rogue states' is observed to decrease with increasing system size. Two mean-field analyses of the macroscopic behaviour are also presented. Copyright 2004 The Royal Society

The dynamic characteristics of HTGR (High Temperature Gas Cooled Reactor) system, (2)

International Nuclear Information System (INIS)

Kudo, Kazuhiko; Ohta, Masao; Kawasaki, Hidenori

1979-01-01

The dynamic characteristics of a HTGR plant, which has two cooling loops, was investigated. The analytical model consists of the core with fuel sleeves, coolant channels and blocks, the upper and lower reflectors, the high and low temperature plenums, two double wall pipings, two intermediate heat exchangers and the secondary system. The key plant parameters for calculation were as follows: the core outlet gas temperature 1000 deg C, the reactor thermal output 50 MW, the flow rate of primary coolant gas 7.96 kg/sec-loop and the pressure of primary coolant gas 40 kg/cm 2 at the rated operating condition. The calculating parameters were fixed as follows: the time interval for core characteristic analysis 0.1 sec, the time interval for thermal characteristic analysis 5.0 sec, the number of division of fuel channels 130, and the number of division of an intermediate heat exchanger 200. The assumptions for making the model were evaluated especially for the power distribution in the core and the heat transmission coefficients in the core, the double wall piping and the intermediate heat exchangers. Concerning the analytical results, the self-control to the outer disturbance of reactivity and the plant dynamic behavior due to the change of flow rate of primary and secondary coolants, and the change of gas temperature of secondary coolant at the inlet of intermediate heat exchangers, are presented. (Nakai, Y.)

Modeling the Gas Dynamics Environment in a Subscale Solid Rocket Test Motor

Science.gov (United States)

Eaton, Andrew M.; Ewing, Mark E.; Bailey, Kirk M.; McCool, Alex (Technical Monitor)

2001-01-01

Subscale test motors are often used for the evaluation of solid rocket motor component materials such as internal insulation. These motors are useful for characterizing insulation performance behavior, screening insulation material candidates and obtaining material thermal and ablative property design data. One of the primary challenges associated with using subscale motors however, is the uncertainty involved when extrapolating the results to full-scale motor conditions. These uncertainties are related to differences in such phenomena as turbulent flow behavior and boundary layer development, propellant particle interactions with the wall, insulation off-gas mixing and thermochemical reactions with the bulk flow, radiation levels, material response to the local environment, and other anomalous flow conditions. In addition to the need for better understanding of physical mechanisms, there is also a need to better understand how to best simulate these phenomena using numerical modeling approaches such as computational fluid dynamics (CFD). To better understand and model interactions between major phenomena in a subscale test motor, a numerical study of the internal flow environment of a representative motor was performed. Simulation of the environment included not only gas dynamics, but two-phase flow modeling of entrained alumina particles like those found in an aluminized propellant, and offgassing from wall surfaces similar to an ablating insulation material. This work represents a starting point for establishing the internal environment of a subscale test motor using comprehensive modeling techniques, and lays the groundwork for improving the understanding of the applicability of subscale test data to full-scale motors. It was found that grid resolution, and inclusion of phenomena in addition to gas dynamics, such as two-phase and multi-component gas composition are all important factors that can effect the overall flow field predictions.

Modeling beam-front dynamics at low gas pressures

International Nuclear Information System (INIS)

Briggs, R.J.; Yu, S.

1982-01-01

The dynamics of space charge neutralization at the front of an intense self-focused electron beam pulse exhibits important differences in different gas pressure regimes. At very low pressures, the beam front is in the so-called ion-focused regime (IFR) where all secondary electrons are expelled from the beam region by the radial electric field without causing significant additional ionization. We estimate the upper pressure boundary of this regime by considering the distance scale length for cascade (avalanche) ionization. Data from the FX-25 diode experiments indicate a critical transition pressure (P/sub c/) that agrees with this estimate and with its scaling among various gas types. Normal mobility-limited treatments (local conductivity models) of the secondary electrons at the beam front are not justified until the gas pressure is 10 to 50 times higher than P/sub c/, due to runaway of these secondary electrons in the strong space-charge electric field at the lower pressures. The main conclusion of this study is that a non-local phase space (Boltzmann) treatment of the secondary electrons is required to accurately describe these different beam front regimes and the transitions between them; such a code model is currently under development

Dynamics of polynomial Chaplygin gas warm inflation

Energy Technology Data Exchange (ETDEWEB)

Jawad, Abdul [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Chaudhary, Shahid [Sharif College of Engineering and Technology, Department of Mathematics, Lahore (Pakistan); Videla, Nelson [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile)

2017-11-15

In the present work, we study the consequences of a recently proposed polynomial inflationary potential in the context of the generalized, modified, and generalized cosmic Chaplygin gas models. In addition, we consider dissipative effects by coupling the inflation field to radiation, i.e., the inflationary dynamics is studied in the warm inflation scenario. We take into account a general parametrization of the dissipative coefficient Γ for describing the decay of the inflaton field into radiation. By studying the background and perturbative dynamics in the weak and strong dissipative regimes of warm inflation separately for the positive and negative quadratic and quartic potentials, we obtain expressions for the most relevant inflationary observables as the scalar power spectrum, the scalar spectral, and the tensor-to-scalar ratio. We construct the trajectories in the n{sub s}-r plane for several expressions of the dissipative coefficient and compare with the two-dimensional marginalized contours for (n{sub s}, r) from the latest Planck data. We find that our results are in agreement with WMAP9 and Planck 2015 data. (orig.)

Gas gun dynamics

International Nuclear Information System (INIS)

Denny, Mark

2013-01-01

The mechanics and thermodynamics of one- and two-stage gas guns are developed. Very high projectile muzzle speed can be obtained by the two-stage version. The physics of simple gas guns, such as air rifles, is accessible to undergraduates and the same level of presentation is used here to understand more complex designs. Numerical solutions to the equations of motion are shown, along with insightful analytic approximations. (paper)

Effects of Gas Rarefaction on Dynamic Characteristics of Micro Spiral-Grooved Thrust Bearing.

Science.gov (United States)

Liu, Ren; Wang, Xiao-Li; Zhang, Xiao-Qing

2012-04-01

The effects of gas-rarefaction on dynamic characteristics of micro spiral-grooved-thrust-bearing are studied. The Reynolds equation is modified by the first order slip model, and the corresponding perturbation equations are then obtained on the basis of the linear small perturbation method. In the converted spiral-curve-coordinates system, the finite-volume-method (FVM) is employed to discrete the surface domain of micro bearing. The results show, compared with the continuum-flow model, that under the slip-flow regime, the decrease in the pressure and stiffness become obvious with the increasing of the compressibility number. Moreover, with the decrease of the relative gas-film-thickness, the deviations of dynamic coefficients between slip-flow-model and continuum-flow-model are increasing.

Dynamic behaviour of high-pressure natural-gas flow in pipelines

International Nuclear Information System (INIS)

Gato, L.M.C.; Henriques, J.C.C.

2005-01-01

The aim of the present study is the numerical modelling of the dynamic behaviour of high-pressure natural-gas flow in pipelines. The numerical simulation was performed by solving the conservation equations, for one-dimensional compressible flow, using the Runge-Kutta discontinuous Galerkin method, with third-order approximation in space and time. The boundary conditions were imposed using a new weak formulation based on the characteristic variables. The occurrence of pressure oscillations in natural-gas pipelines was studied as a result of the compression wave originated by the rapid closure of downstream shut-off valves. The effect of the partial reflection of pressure waves was also analyzed in the transition between pipes of different cross-sectional areas

Dynamic behaviour of high-pressure natural-gas flow in pipelines

Energy Technology Data Exchange (ETDEWEB)

Gato, L.M.C. [Department of Mechanical Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)]. E-mail: lgato@mail.ist.utl.pt; Henriques, J.C.C. [Department of Mechanical Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)]. E-mail: jcch@mail.ist.utl.pt

2005-10-01

The aim of the present study is the numerical modelling of the dynamic behaviour of high-pressure natural-gas flow in pipelines. The numerical simulation was performed by solving the conservation equations, for one-dimensional compressible flow, using the Runge-Kutta discontinuous Galerkin method, with third-order approximation in space and time. The boundary conditions were imposed using a new weak formulation based on the characteristic variables. The occurrence of pressure oscillations in natural-gas pipelines was studied as a result of the compression wave originated by the rapid closure of downstream shut-off valves. The effect of the partial reflection of pressure waves was also analyzed in the transition between pipes of different cross-sectional areas.

Collective dynamics in noble-gas and other very simple classical fluids

Directory of Open Access Journals (Sweden)

U.Bafile

2008-03-01

Full Text Available Rare gases and their liquids are the simplest systems to study for accurate investigations of the collective dynamics of fluid matter. Much work has been done using different spectroscopic techniques, molecular-dynamics simulations, and theoretical developments, in order to gain insight into the microscopic processes involved, in particular, in the propagation of acoustic excitations in gases and liquids. Here we briefly review the interpretation schemes currently applied to the characterization of such excitations, and recall a few results obtained from the analysis of rare-gas fluids and other very simple systems.

Robust Design of SAW Gas Sensors by Taguchi Dynamic Method

Directory of Open Access Journals (Sweden)

Hsun-Heng Tsai

2009-02-01

Full Text Available This paper adopts Taguchi’s signal-to-noise ratio analysis to optimize the dynamic characteristics of a SAW gas sensor system whose output response is linearly related to the input signal. The goal of the present dynamic characteristics study is to increase the sensitivity of the measurement system while simultaneously reducing its variability. A time- and cost-efficient finite element analysis method is utilized to investigate the effects of the deposited mass upon the resonant frequency output of the SAW biosensor. The results show that the proposed methodology not only reduces the design cost but also promotes the performance of the sensors.

Kinetics and dynamics of near-resonant vibrational energy transfer in gas ensembles of atmospheric interest

Science.gov (United States)

McCaffery, Anthony J.

2018-03-01

This study of near-resonant, vibration-vibration (V-V) gas-phase energy transfer in diatomic molecules uses the theoretical/computational method, of Marsh & McCaffery (Marsh & McCaffery 2002 J. Chem. Phys. 117, 503 (doi:10.1063/1.1489998)) The method uses the angular momentum (AM) theoretical formalism to compute quantum-state populations within the component molecules of large, non-equilibrium, gas mixtures as the component species proceed to equilibration. Computed quantum-state populations are displayed in a number of formats that reveal the detailed mechanism of the near-resonant V-V process. Further, the evolution of quantum-state populations, for each species present, may be followed as the number of collision cycles increases, displaying the kinetics of evolution for each quantum state of the ensemble's molecules. These features are illustrated for ensembles containing vibrationally excited N2 in H2, O2 and N2 initially in their ground states. This article is part of the theme issue `Modern theoretical chemistry'.

Response Functions for the Two-Dimensional Ultracold Fermi Gas: Dynamical BCS Theory and Beyond

Science.gov (United States)

Vitali, Ettore; Shi, Hao; Qin, Mingpu; Zhang, Shiwei

2017-12-01

Response functions are central objects in physics. They provide crucial information about the behavior of physical systems, and they can be directly compared with scattering experiments involving particles such as neutrons or photons. Calculations of such functions starting from the many-body Hamiltonian of a physical system are challenging and extremely valuable. In this paper, we focus on the two-dimensional (2D) ultracold Fermi atomic gas which has been realized experimentally. We present an application of the dynamical BCS theory to obtain response functions for different regimes of interaction strengths in the 2D gas with zero-range attractive interaction. We also discuss auxiliary-field quantum Monte Carlo (AFQMC) methods for the calculation of imaginary time correlations in these dilute Fermi gas systems. Illustrative results are given and comparisons are made between AFQMC and dynamical BCS theory results to assess the accuracy of the latter.

Canadian natural gas

International Nuclear Information System (INIS)

Lucas, D.A.

1991-01-01

Canada's natural gas industry enjoys a quiet confidence as it looks ahead to the 1990s. In this paper, the author explains why, despite some critical uncertainties, the optimism endures. Reviewing the current conditions of supply, production, consumption, pipelines, and pipeline expansion plans, the author contends that the New World of the 1990s will belong to natural gas. The author's assessment of natural gas markets proceeds far beyond the borders of Canada. The author examines the determinants of gas prices throughout North America and he identifies the one force that promises to seize almost complete control of gas prices throughout the continent. While the analysis points out the attributes of this new pricing regime, it also names the obstacles that could prevent this emerging mechanism from assuming its anticipated position

Evolution of collision numbers for a chaotic gas dynamics.

Science.gov (United States)

Vidgop, Alexander Jonathan; Fouxon, Itzhak

2011-11-01

We put forward a conjecture of recurrence for a gas of hard spheres that collide elastically in a finite volume. The dynamics consists of a sequence of instantaneous binary collisions. We study how the numbers of collisions of different pairs of particles grow as functions of time. We observe that these numbers can be represented as a time integral of a function on the phase space. Assuming the results of the ergodic theory apply, we describe the evolution of the numbers by an effective Langevin dynamics. We use the facts that hold for these dynamics with probability one, in order to establish properties of a single trajectory of the system. We find that for any triplet of particles there will be an infinite sequence of moments of time, when the numbers of collisions of all three different pairs of the triplet will be equal. Moreover, any value of difference of collision numbers of pairs in the triplet will repeat indefinitely. On the other hand, for larger numbers of pairs there is but a finite number of repetitions. Thus the ergodic theory produces a limitation on the dynamics.

Parametric study on ship’s exhaust-gas behavior using computational fluid dynamics

Directory of Open Access Journals (Sweden)

Sunho Park

2017-01-01

Full Text Available The influence of design parameters related to a ship’s exhaust-gas behavior was investigated using computational fluid dynamics (CFD for an 8,000 TEU container carrier. To verify the numerical methods, the results were studied by comparing with experimental results. Several test conditions, i.e. various load conditions of ship, wind angle, deckhouse breadth, radar mast height, and exhaust-pipe height and shape were considered for a ship’s exhaust gas flow around the 8,000 TEU container carrier. The influence of the design parameters on contamination by the exhaust gas was quantified, after which the principal parameters to avoid contamination were selected. Finally, the design guideline of yP/H = 2 was suggested to avoid the contamination from the ship’s exhaust gas using the CFD results, model tests, and sea trials.

Modelling dynamic liquid-gas systems: Extensions to the volume-of-fluid solver

CSIR Research Space (South Africa)

Heyns, Johan A

2013-06-01

Full Text Available This study presents the extension of the volume-of-fluid solver, interFoam, for improved accuracy and efficiency when modelling dynamic liquid-gas systems. Examples of these include the transportation of liquids, such as in the case of fuel carried...

Proceedings of advanced software in robotics

Energy Technology Data Exchange (ETDEWEB)

Danthine, A; Geradin, M

1983-01-01

The following topics were dealt with: kinematics and dynamics modelling; adaptive control; languages; geometric modelling; system architecture; computing aspects of sensing devices; and artificial intellligence. 30 papers were presented, of which all are published in full in the present proceedings. Abstracts of individual papers can be found under the relevant classification codes in this or future issues.

Proceedings of the natural gas research and development contractors review meeting

Energy Technology Data Exchange (ETDEWEB)

Malone, R.D.; Shoemaker, H.D.; Byrer, C.W. (eds.)

1990-11-01

The purpose of this meeting was to present results of the research in the DOE-sponsored Natural Gas Program, and simultaneously to provide a forum for real-time technology transfer, to the active research community, to the interested public, and to the natural gas industry, who are the primary users of this technology. The current research focus is to expand the base of near-term and mid-term economic gas resources through research activities in Eastern Tight Gas, Western Tight Gas, Secondary Gas Recovery (increased recovery of gas from mature fields); to enhance utilization, particularly of remote gas resources through research in Natural Gas to Liquids Conversion; and to develop additional, long term, potential gas resources through research in Gas Hydrates and Deep Gas. With the increased national emphasis on the use of natural gas, this forum has been expanded to include summaries of DOE-sponsored research in energy-related programs and perspectives on the importance of gas to future world energy. Thirty-two papers and fourteen poster presentations were given in seven formal, and one informal, sessions: Three general sessions (4 papers); Western Tight Gas (6 papers); Eastern Tight Gas (8 papers); Conventional/Speculative Resources (8 papers); and Gas to Liquids (6 papers). Individual reports are processed separately on the data bases.

Dynamic Stability Study of Static Gas Bearing for Small Cryogenic Turbo-Expander

International Nuclear Information System (INIS)

Wang Xuemin; Zhuang Ming; Zhang Qiyong; Li Shanshan; Fu Bao

2011-01-01

An experimental method is presented to analyze the dynamic stability of the gas bearing for small cryogenic turbo-expanders. The rotation imbalance response and the shape of the rotor orbit were obtained for different speeds up to 110,000 rpm, and the critical speed of the rotor-bearing system was determined by a Bode diagram. An FFT signal analytical method was applied to identify the resonance frequency, and the waterfall plot was presented. During the whole process of speeding up to the designed speed of 110,000 rpm, the rotor-bearing works stably with no whirl instability, which is validated in a waterfall plot. Also, the tested rotor-bearing model was analyzed theoretically. It was proved that the experimental results were highly consistent with those of theoretical calculations. Thus the experimental method proposed here to analyze the dynamic stability of the gas bearing is feasible. (fusion engineering)

Quantum quench dynamics of the attractive one-dimensional Bose gas via the coordinate Bethe ansatz

Directory of Open Access Journals (Sweden)

Jan C. Zill, Tod M. Wright, Karen V. Kheruntsyan, Thomas Gasenzer, Matthew J. Davis

2018-02-01

Full Text Available We use the coordinate Bethe ansatz to study the Lieb-Liniger model of a one-dimensional gas of bosons on a finite-sized ring interacting via an attractive delta-function potential. We calculate zero-temperature correlation functions for seven particles in the vicinity of the crossover to a localized solitonic state and study the dynamics of a system of four particles quenched to attractive interactions from the ideal-gas ground state. We determine the time evolution of correlation functions, as well as their temporal averages, and discuss the role of bound states in shaping the postquench correlations and relaxation dynamics.

The development and application of dynamic operational risk assessment in oil/gas and chemical process industry

International Nuclear Information System (INIS)

Yang Xiaole; Mannan, M. Sam

2010-01-01

A methodology of dynamic operational risk assessment (DORA) is proposed for operational risk analysis in oil/gas and chemical industries. The methodology is introduced comprehensively starting from the conceptual framework design to mathematical modeling and to decision making based on cost-benefit analysis. The probabilistic modeling part of DORA integrates stochastic modeling and process dynamics modeling to evaluate operational risk. The stochastic system-state trajectory is modeled according to the abnormal behavior or failure of each component. For each of the possible system-state trajectories, a process dynamics evaluation is carried out to check whether process variables, e.g., level, flow rate, temperature, pressure, or chemical concentration, remain in their desirable regions. Component testing/inspection intervals and repair times are critical parameters to define the system-state configuration, and play an important role for evaluating the probability of operational failure. This methodology not only provides a framework to evaluate the dynamic operational risk in oil/gas and chemical industries, but also guides the process design and further optimization. To illustrate the probabilistic study, we present a case-study of a level control in an oil/gas separator at an offshore plant.

Dynamics of exciplex formation in rare gas media

International Nuclear Information System (INIS)

Rojas-Lorenzo, German; Rubayo-Soneira, Jesus; Alberti, Sebastian Fernandez

2009-01-01

A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ( 1 S 0 → 3 P 1 ) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its 3 P 1 electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg * -Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

Gas flow characteristics of a time modulated APPJ: the effect of gas heating on flow dynamics

International Nuclear Information System (INIS)

Zhang, S; Sobota, A; Van Veldhuizen, E M; Bruggeman, P J

2015-01-01

This work investigates the flow dynamics of a radio-frequency (RF) non-equilibrium argon atmospheric pressure plasma jet. The RF power is at a frequency of 50 Hz or 20 kHz. Combined flow pattern visualizations (obtained by shadowgraphy) and gas temperature distributions (obtained by Rayleigh scattering) are used to study the formation of transient vortex structures in initial flow field shortly after the plasma is switched on and off in the case of 50 Hz modulation. The transient vortex structures correlate well with observed temperature differences. Experimental results of the fast modulated (20 kHz) plasma jet that does not induce changes of the gas temperature are also presented. The latter result suggests that momentum transfer by ions does not have dominant effect on the flow pattern close to the tube. It is argued that the increased gas temperature and corresponding gas velocity increase at the tube exit due to the plasma heating increases the admixing of surrounding air and reduces the effective potential core length. With increasing plasma power a reduction of the effective potential core length is observed with a minimum length for 5.6 W after which the length extends again. Possible mechanisms related to viscosity effects and ionic momentum transfer are discussed. (paper)

Gas dynamic virtual nozzle for generation of microscopic droplet streams

Energy Technology Data Exchange (ETDEWEB)

DePonte, D P; Weierstall, U; Schmidt, K; Warner, J; Starodub, D; Spence, J C H; Doak, R B [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States)], E-mail: dandeponte@gmail.com

2008-10-07

As shown by Ganan-Calvo (1998 Phys. Rev. Lett. 80 285-8), a free liquid jet can be compressed in diameter through gas dynamic forces exerted by a coaxially co-flowing gas, obviating the need for a solid nozzle to form a microscopic liquid jet and thereby alleviating the clogging problems that plague conventional droplet sources of small diameter. We describe in this paper a novel form of droplet beam source based on this principle. The source is miniature, robust, dependable, easily fabricated, essentially immune to clogging and eminently suitable for delivery of microscopic liquid droplets, including hydrated biological samples, into vacuum for analysis using vacuum instrumentation. Monodisperse, single-file droplet streams are generated by triggering the device with a piezoelectric actuator.

IUTAM Symposium on Hamiltonian Dynamics, Vortex Structures, Turbulence

CERN Document Server

Borisov, Alexey V; Mamaev, Ivan S; Sokolovskiy, Mikhail A; IUTAM BOOKSERIES : Volume 6

2008-01-01

This work brings together previously unpublished notes contributed by participants of the IUTAM Symposium on Hamiltonian Dynamics, Vortex Structures, Turbulence (Moscow, 25-30 August 2006). The study of vortex motion is of great interest to fluid and gas dynamics: since all real flows are vortical in nature, applications of the vortex theory are extremely diverse, many of them (e.g. aircraft dynamics, atmospheric and ocean phenomena) being especially important. The last few decades have shown that serious possibilities for progress in the research of real turbulent vortex motions are essentially related to the combined use of mathematical methods, computer simulation and laboratory experiments. These approaches have led to a series of interesting results which allow us to study these processes from new perspectives. Based on this principle, the papers collected in this proceedings volume present new results on theoretical and applied aspects of the processes of formation and evolution of various flows, wave a...

A time-dependent dusty gas dynamic model of axisymmetric cometary jets

International Nuclear Information System (INIS)

Korosmezey, A.; Gombosi, T.I.

1990-01-01

The present time-dependent, axisymmetric dusty gas dynamical model of inner cometary atmospheres solves the coupled and time-dependent equations of continuity, momentum, and energy for a gas-dust mixture between the surface of the nucleus and 100 km, using an axisymmetric 40 x 40 grid structure. A novel numerical method employing a second-order accurate Godunov-type scheme with dimensional splitting is used to solve the time-dependent pde system. It is established that a subsolar dust spike not predicted by previous calculations is generated by narrow axisymmetric jets, together with a jet cone whose opening angle depends on the jet length. 28 refs

A dynamic model of gas flow in a non-uniform pipe

International Nuclear Information System (INIS)

Mensah, S.; Lepp, R.M.

1979-08-01

A gas-line model, based on the analysis of compressible flow with friction, has been developed to describe the dynamics of gas flow in a non-uniform line, i.e. one comprising segments of different lengths and diameters. Acoustic wave analysis was used in a novel way, by considering the line as a cascaded connection of uniform pipes separated by discontinuities. The transmission matrix representing this non-uniform line is the product of the matrices for each element in the system. To facilitate implementation of the theoretical model on a hybrid computer, modal approximatons to its transfer functions were derived. Both models were validated against experimental data. (author)

Proceedings of second international conference on vibration engineering and technology of machinery

International Nuclear Information System (INIS)

2002-12-01

This volume of proceedings of the conference on vibration engineering cover a wide range of fields spanning diagnostics and condition monitoring, dynamics of rotors, dynamics of structures, computational methods, vehicle dynamics, vibration control, fluid-structure interaction, random and non-linear vibration. Many of these topics are also important to nuclear industry. The papers relevant to INIS are indexed separately

Anisotropic relaxation dynamics in a dipolar Fermi gas driven out of equilibrium

DEFF Research Database (Denmark)

Aikawa, K.; Frisch, A.; Mark, M.

2014-01-01

We report on the observation of a large anisotropy in the rethermalization dynamics of an ultracold dipolar Fermi gas driven out of equilibrium. Our system consists of an ultracold sample of strongly magnetic $^{167}$Er fermions, spin-polarized in the lowest Zeeman sublevel. In this system, elastic...

Gas dynamics considerations in a non-invasive profile monitor for charged particle beams

CERN Document Server

Tzoganis, Vasilis; Welsch, Carsten P

2014-01-01

A non-invasive, gas jet-based, beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This allows on-line measurement of the 2-dimensional transverse profile of particle beams with negligible disturbance to either primary beam or accelerator vacuum. The monitor is suitable for use with beams across a wide range of energies and intensities. In this setup a nozzle-skimmer system shapes a thin supersonic gas jet into a curtain. However, the small dimensions of the gas inlet nozzle and subsequent skimmers were shown to be the cause of many operational problems. In this paper, the dynamics of gas jet formation transport and shaping is discussed before an image-processing based alignment technique is introduced. Furthermore, experimental results obtained with a 5 keV electron beam are discussed and the effects of gas stagnation pressure on the acquired beam are presented.

Proceedings of the flexible, midsize gas turbine program planning workshop

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The US Department of Energy (DOE) and the California Energy Commission (CEC) held a program planning workshop on March 4--5, 1997 in Sacramento, California on the subject of a flexible, midsize gas turbine (FMGT). The workshop was also co-sponsored by the Electric Power Research Institute (EPRI), the Gas Research Institute (GRI), the Gas Turbine Association (GTA), and the Collaborative Advanced Gas Turbine Program (CAGT). The purpose of the workshop was to bring together a broad cross section of knowledgeable people to discuss the potential benefits, markets, technical attributes, development costs, and development funding approaches associated with making this new technology available in the commercial marketplace. The participants in the workshop included representatives from the sponsoring organizations, electric utilities, gas utilities, independent power producers, gas turbine manufacturers, gas turbine packagers, and consultants knowledgeable in the power generation field. Thirteen presentations were given on the technical and commercial aspects of the subject, followed by informal breakout sessions that dealt with sets of questions on markets, technology requirements, funding sources and cost sharing, and links to other programs.

Explorations in the History of Machines and Mechanisms : Proceedings of HMM2012

CERN Document Server

Ceccarelli, Marco

2012-01-01

This book contains the proceedings of HMM2012, the 4th International Symposium on Historical Developments in the field of Mechanism and Machine Science (MMS). These proceedings cover recent research concerning all aspects of the development of MMS from antiquity until the present and its historiography: machines, mechanisms, kinematics, dynamics, concepts and theories, design methods, collections of methods, collections of models, institutions and biographies.

The effect of gas double-dynamic on mass distribution in solid-state fermentation.

Science.gov (United States)

Chen, Hong-Zhang; Zhao, Zhi-Min; Li, Hong-Qiang

2014-05-10

The mass distribution regularity in substrate of solid-state fermentation (SSF) has rarely been reported due to the heterogeneity of solid medium and the lack of suitable instrument and method, which limited the comprehensive analysis and enhancement of the SSF performance. In this work, the distributions of water, biomass, and fermentation product in different medium depths of SSF were determined using near-infrared spectroscopy (NIRS) and the developed models. Based on the mass distribution regularity, the effects of gas double-dynamic on heat transfer, microbial growth and metabolism, and product distribution gradient were systematically investigated. Results indicated that the maximum temperature of substrate and the maximum carbon dioxide evolution rate (CER) were 39.5°C and 2.48mg/(hg) under static aeration solid-state fermentation (SASSF) and 33.9°C and 5.38mg/(hg) under gas double-dynamic solid-state fermentation (GDSSF), respectively, with the environmental temperature for fermentation of 30±1°C. The fermentation production (cellulase activity) ratios of the upper, middle, and lower levels were 1:0.90:0.78 at seventh day under SASSF and 1:0.95:0.89 at fifth day under GDSSF. Therefore, combined with NIRS analysis, gas double-dynamic could effectively strengthen the solid-state fermentation performance due to the enhancement of heat transfer, the stimulation of microbial metabolism and the increase of the homogeneity of fermentation products. Copyright © 2014 Elsevier Inc. All rights reserved.

A system dynamic model for production and consumption policy in Iran oil and gas sector

International Nuclear Information System (INIS)

Kiani, Behdad; Ali Pourfakhraei, Mohammad

2010-01-01

A system dynamic model is presented, which considers the feedback between supply and demand and oil revenue of the existing system in Iran considering different sectors of the economy. Also the export of the oil surplus and the injection of the gas surplus into the oil reservoirs are seen in the model by establishing a balance between supply and demand. In this model the counter-effects and existing system feedbacks between supply and demand and oil revenue can be seen considering different sectors of the economy. As a result, the effects of oil and gas policies in different scenarios for different sectors of Iran's economy together with the counter-effects of energy consumption and oil revenue are examined. Three scenarios, which show the worst, base and ideal cases, are considered to find future trends of major variables such as seasonal gas consumption in power plants, seasonal injected gas in oil reservoirs, economic growth in the industrial sector, oil consumption in the transportation sector, industrial gas consumption and exported gas. For example, it is shown that the exported gas will reach between 500 and 620 million cubic-meter per day in different scenarios and export revenues can reach up to $500 billion by 2025. - Research Highlights: →A system dynamic model analyzing the feedback between supply, demand and oil revenue is built. →The export of the oil surplus and the injection of the gas surplus into oil reservoirs are modeled. →Effects of oil and gas policies in different scenarios are examined for Iran's economy. →Counter-effects of energy consumption and oil revenue are examined. →Exported gas will reach between 500 and 620 million cubic-meter per day in different scenarios. →Export revenues can reach up to $500 billion by 2025.

Experimental investigation of the dynamics in a strongly interacting Fermi gas : collective modes and rotational properties

International Nuclear Information System (INIS)

Riedl, S.

2009-01-01

This thesis explores the dynamics in an ultracold strongly interacting Fermi gas. Therefore we perform measurements on collective excitation modes and rotational properties of the gas. The strongly interacting gas is realized using an optically trapped Fermi gas of 6 Li atoms, where the interactions can be tuned using a broad Feshbach resonance. Our measurements allow to test the equation of state of the gas, study the transition from hydrodynamic to collisionless behavior, reveal almost ideal hydrodynamic behavior in the nonsuperfluid phase, investigate the lifetime of angular momentum, and show superfluidity through the quenching of the moment of inertia. (author)

Gas dynamic lasers

International Nuclear Information System (INIS)

Hill, R.J.; Jewell, N.T.

1975-01-01

In a high powered laser system it is proposed that combustion gases be bled off from a gas turbine engine and their composition adjusted by burning extra fuel in the bleed gases or adding extra substances. Suitable aerodynamic expansion produces a population inversion resulting in laser action in the CO 2 species. Alternatively, bleed gases may be taken from the high pressure compressor of the gas turbine engine and an appropriate fuel burned therein. If required, other adjustments may also be made to the composition and the resulting gaseous mixture subjected to aerodynamic expansion to induce laser action as before. (auth)

Plasma excitation processes in flue gas simulated with Monte Carlo electron dynamics

Energy Technology Data Exchange (ETDEWEB)

Tas, M.A.; Veldhuizen, E.M. van; Rutgers, W.R. [Eindhoven University of Technology (Netherlands). Div. of Electrical Energy Systems

1997-06-07

The excitation of gas molecules in flue gas by electron impact is calculated with a Monte Carlo (MC) algorithm for electron dynamics in partially ionized gases. The MC algorithm is straightforward for any mixture of molecules for which cross sections are available. Electron drift is simulated in the first case for homogeneous electric fields and in the second case for secondary electrons which are produced by electron-beam irradiation. The electron energy distribution function {epsilon}-bar{sub {theta}}, V-bar{sub d}, {lambda}-bar, the energy branching and the rate of excitation are calculated for standard gas mixtures of Ar-N{sub 2}, O{sub 2} and H{sub 2}O. These fundamental process parameters are needed for the study of reactions to remove NO{sub x} from flue gas. The calculated results indicate that the production of highly excited molecules in the high electric field of a streamer corona discharge has an efficiency similar to that of electron-beam irradiation. (author)

Quantum versus classical statistical dynamics of an ultracold Bose gas

International Nuclear Information System (INIS)

Berges, Juergen; Gasenzer, Thomas

2007-01-01

We investigate the conditions under which quantum fluctuations are relevant for the quantitative interpretation of experiments with ultracold Bose gases. This requires to go beyond the description in terms of the Gross-Pitaevskii and Hartree-Fock-Bogoliubov mean-field theories, which can be obtained as classical (statistical) field-theory approximations of the quantum many-body problem. We employ functional-integral techniques based on the two-particle irreducible (2PI) effective action. The role of quantum fluctuations is studied within the nonperturbative 2PI 1/N expansion to next-to-leading order. At this accuracy level memory integrals enter the dynamic equations, which differ for quantum and classical statistical descriptions. This can be used to obtain a classicality condition for the many-body dynamics. We exemplify this condition by studying the nonequilibrium evolution of a one-dimensional Bose gas of sodium atoms, and discuss some distinctive properties of quantum versus classical statistical dynamics

Numerical studies of neon gas-puff Z-pinch dynamic processes

International Nuclear Information System (INIS)

Ning Cheng; Yang Zhenhua; Ding Ning

2003-01-01

Dynamic processes of neon gas-puff Z-pinch are studied numerically in this paper. A high temperature plasma with a high density can be generated in the process. Based on some physical analysis and assumption, a set of equations of one-dimensional Lagrangian radiation magneto-hydrodynamic (MHD) and its code are developed to solve the problem. Spatio-temporal distributions of plasma parameters in the processes are obtained, and their dynamic variations show that the major results are self-consistent. The duration for the plasma pinched to centre, as well as the width and the total energy of the x-ray pulse caused by the Z-pinch are in reasonable agreement with experimental results of GAMBLE-II. A zipping effect is also clearly shown in the simulation

Proceedings, 15th central hardwood forest conference

Science.gov (United States)

David S. Buckley; Wayne K. Clatterbuck; [Editors

2007-01-01

Proceedings of the 15th central hardwood forest conference held February 27–March 1, 2006, in Knoxville, TN. Includes 86 papers and 30 posters pertaining to forest health and protection, ecology and forest dynamics, natural and artificial regeneration, forest products, wildlife, site classification, management and forest resources, mensuration and models, soil and...

Investigation of interface boundary occurring during cold gas-dynamic spraying of metallic particles

CERN Document Server

Bolesta, A V; Sharafutdinov, M R; Tolochko, B P

2001-01-01

An interface boundary occurring during cold gas dynamic spraying of aluminum particles on a nickel substrate has been studied by the method of X-ray grazing diffraction. Presence of boundary phase of the intermetallic compound Ni sub 3 Al was found.

The Experimental Study of Dynamics of Scaled Gas-Filled Bubble Collapse in Liquid

Science.gov (United States)

Pavlenko, Alexander

2011-06-01

The article provides results of analyzing special features of the single-bubble sonoluminescence, developing the special apparatus to investigate this phenomenon on a larger-scale basis. Certain very important effects of high energy density physics, i.e. liquid compressibility, shock-wave formation under the collapse of the gas cavity in liquid, shock-wave focusing in the gas-filled cavity, occurrence of hot dense plasma in the focusing area, and high-temperature radiation yield are observed in this phenomenon. Specificity of the process is conditioned by the ``ideal'' preparation and sphericity of the gas-and-liquid contact boundary what makes the collapse process efficient due to the reduced influence of hydrodynamic instabilities. Results of experimental investigations; results of developing the facilities, description of methods used to register parameters of facilities and the system under consideration; analytical estimates how gas-filled bubbles evolve in liquid with the regard for scale effects; results of preliminary 1-D gas dynamic calculations of the gas bubble evolution are presented. The work supported by ISTC Project #2116.

Topological phase transition in the quench dynamics of a one-dimensional Fermi gas

OpenAIRE

Wang, Pei; Yi, Wei; Xianlong, Gao

2014-01-01

We study the quench dynamics of a one-dimensional ultracold Fermi gas in an optical lattice potential with synthetic spin-orbit coupling. At equilibrium, the ground state of the system can undergo a topological phase transition and become a topological superfluid with Majorana edge states. As the interaction is quenched near the topological phase boundary, we identify an interesting dynamical phase transition of the quenched state in the long-time limit, characterized by an abrupt change of t...

Set-Up and Validation of a Dynamic Solid/Gas Bioreactor

KAUST Repository

Lloyd-Randol, Jennifer D.

2012-05-01

The limited availability of fossil resourses mandates the development of new energy vectors, which is one of the Grand Challenges of the 21st Century [1]. Biocatalytic energy conversion is a promising solution to meet the increased energy demand of industrialized societies. Applications of biocatalysis in the gas-phase are so far limited to production of fine chemicals and pharmaceuticals. However, this technology has the potential for large scale biocatalytic applications [2], e.g. for the formation of novel energy carriers. The so-called solid/gas biocatalysis is defined as the application of a biocatalyst immobilized on solid-phase support acting on gaseous substrates [3]. This process combines the advantages of bio-catalysis (green chemistry, mild reaction conditions, high specicity & selectivity) and heterogeneous dynamic gas-phase processes (low diffusion limitation, high conversion, simple scale-up). This work presents the modifications of a PID Microactivity Reference reactor in order to make it suitable for solid/gas biocatalysis. The reactor design requirements are based on previously published laboratory scale solid/gas systems with a feed of saturated vapors [4]. These vapors are produced in saturation flasks, which were designed and optimized during this project. Other modifications included relocation of the gas mixing chamber, redesigning the location and heating mechanism for the reactor tube, and heating of the outlet gas line. The modified reactor system was verified based on the Candida antarctica lipase B catalyzed transesterication of ethyl acetate with 1-hexanol to hexyl acetate and ethanol and results were compared to liquid-phase model reactions. Products were analyzed on line by a gas chromatograph with a flame ionization detector. C. antarc- tica physisorbed on silica particles produced a 50% conversion of hexanol at 40 C in the gas-phase. A commercial immobilized lipase from Iris Biotech produced 99% and 97% conversions of hexanol in

Action of illuminating gas on plants. I. Action of the gas on the germination of spores and seeds

Energy Technology Data Exchange (ETDEWEB)

Weiimer, C

1917-01-01

Experiments were performed to determine the effects of coal gas on plants. Results indicate that anaerobic fungi can grow even in undiluted gas and cress seeds (Lepidium sativum) remain alive for weeks in undiluted gas, but the seeds can germinate normally if the gas is diluted 5 times its volume of air. However, if the gas is passed through the soil in which the seeds have been placed, they will not germinate. If water is added to the soil, germination can proceed normally. The chemicals of coal gas which affects plants include sulfur compounds, benzene and ethylene. Carbon monoxide is also a prime constituent of coal gas, but it has no affect on plants.

Nonlinear dynamics of cycle-to-cycle combustion variations in a lean-burn natural gas engine

Energy Technology Data Exchange (ETDEWEB)

Li Guoxiu [School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China)], E-mail: gxli@bjtu.edu.cn; Yao Baofeng [School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China)

2008-04-15

Temporal dynamics of the combustion process in a lean-burn natural gas engine was studied by the analysis of time series of consecutive experimental in-cylinder pressure data in this work. Methods borrowed to the nonlinear dynamical system theory were applied to analyze the in-cylinder pressure time series under operating conditions with different equivalence ratio. Phase spaces were reconstructed from the in-cylinder pressure time series and Poincare section calculated from each phase space. Poincare sections show that the in-cylinder combustion process involves chaotic behavior. Furthermore, return maps plotted from time series of indicated mean effective pressure show that both nonlinear deterministic components and stochastic components are involved in the dynamics of cycle-to-cycle combustion variations in the lean burn natural gas engine. There is a transition from stochastic behavior to noisy nonlinear determinism as equivalence ratio decreases from near stoichiometric to very lean conditions.

Nonlinear dynamics of cycle-to-cycle combustion variations in a lean-burn natural gas engine

International Nuclear Information System (INIS)

Li Guoxiu; Yao Baofeng

2008-01-01

Temporal dynamics of the combustion process in a lean-burn natural gas engine was studied by the analysis of time series of consecutive experimental in-cylinder pressure data in this work. Methods borrowed to the nonlinear dynamical system theory were applied to analyze the in-cylinder pressure time series under operating conditions with different equivalence ratio. Phase spaces were reconstructed from the in-cylinder pressure time series and Poincare section calculated from each phase space. Poincare sections show that the in-cylinder combustion process involves chaotic behavior. Furthermore, return maps plotted from time series of indicated mean effective pressure show that both nonlinear deterministic components and stochastic components are involved in the dynamics of cycle-to-cycle combustion variations in the lean burn natural gas engine. There is a transition from stochastic behavior to noisy nonlinear determinism as equivalence ratio decreases from near stoichiometric to very lean conditions

STUDY OF GAS SEPARATION PROCESS BY DYNAMIC ADSORPTION IN FIXED BED

Directory of Open Access Journals (Sweden)

Ioan Solomon

2010-10-01

Full Text Available An experimental study of mass transfer at gas separation by dynamic adsorption in fixed bed of impregnated silica gel is presented in this work. By means of a mathematical model based on constants and coefficient easy to evaluate, the distributions of adsorbate concentration in gas and solid phases were determined as a function of time and throughout the height of the fixed bed, under isothermal conditions.With this aim, water vapors from air were adsorbed in a fixed bed of impregnated silica gel. The values of the volumetric mass transfer coefficient, Kv, were determined experimentally at several values of air superficial velocity, an air relative humidity of 69�20at 38 °C. The influence of the gas flow velocity and initial water concentration in adsorbent on the distribution of water concentration in both phases was established as a function of time and throughout the height of the fixed bed. The results obtained allow one to determination of the local adsorption rate.

Protein structural dynamics at the gas/water interface examined by hydrogen exchange mass spectrometry.

Science.gov (United States)

Xiao, Yiming; Konermann, Lars

2015-08-01

Gas/water interfaces (such as air bubbles or foam) are detrimental to the stability of proteins, often causing aggregation. This represents a potential problem for industrial processes, for example, the production and handling of protein drugs. Proteins possess surfactant-like properties, resulting in a high affinity for gas/water interfaces. The tendency of previously buried nonpolar residues to maximize contact with the gas phase can cause significant structural distortion. Most earlier studies in this area employed spectroscopic tools that could only provide limited information. Here we use hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for probing the conformational dynamics of the model protein myoglobin (Mb) in the presence of N(2) bubbles. HDX/MS relies on the principle that unfolded and/or highly dynamic regions undergo faster deuteration than tightly folded segments. In bubble-free solution Mb displays EX2 behavior, reflecting the occurrence of short-lived excursions to partially unfolded conformers. A dramatically different behavior is seen in the presence of N(2) bubbles; EX2 dynamics still take place, but in addition the protein shows EX1 behavior. The latter results from interconversion of the native state with conformers that are globally unfolded and long-lived. These unfolded species likely correspond to Mb that is adsorbed to the surface of gas bubbles. N(2) sparging also induces aggregation. To explain the observed behavior we propose a simple model, that is, "semi-unfolded" ↔ "native" ↔ "globally unfolded" → "aggregated". This model quantitatively reproduces the experimentally observed kinetics. To the best of our knowledge, the current study marks the first exploration of surface denaturation phenomena by HDX/MS. © 2015 The Protein Society.

Automotive exhaust gas conversion: from elementary step kinetics to prediction of emission dynamics

NARCIS (Netherlands)

Hoebink, J.H.B.J.; Harmsen, J.M.A.; Balenovic, M.; Backx, A.C.P.M.; Schouten, J.C.

2001-01-01

Elementary step based kinetics show a high added value to describe the performance of catalytic exhaust gas converters under dynamic conditions, as demonstrated with a Euro test cycle. Combination of such kinetic models for individual global reactions covers the mutual interactions via common

Future evolution of the liberalised European gas market: Simulation results with a dynamic model

Energy Technology Data Exchange (ETDEWEB)

Lise, Wietze [IBS Research and Consultancy, Aga Han, Agahamami Cadessi 1/6, Cihangir, 34433 Beyoglu, Istanbul (Turkey); Energy Markets and International Environmental Policy group, ECN Policy Studies, Energy Research Centre of the Netherlands, Amsterdam (Netherlands); Hobbs, Benjamin F. [Department of Geography and Environmental Engineering, The Johns Hopkins University, Ames Hall 313, 3400 North Charles Street, Baltimore, MD 21218 (United States)

2008-07-15

Strategic behaviour by gas producers is likely to affect future gas prices and investments in the European Union (EU). To analyse this issue, a computational game theoretic model is presented that is based on a recursive-dynamic formulation. This model addresses interactions among demand, supply, pipeline and liquefied natural gas (LNG) transport, storage and investments in the natural gas market over the period 2005-2030. Three market scenarios are formulated to study the impact of producer market power. In addition, tradeoffs among investments in pipelines, LNG liquefaction and regasification facilities, and storage are explored. The model runs indicate that LNG can effectively compete with pipelines in the near future. Further, significant decreases in Cournot prices between 2005 and 2010 indicate that near-term investments in EU gas transport capacity are likely to diminish market power by making markets more accessible. (author)

Future evolution of the liberalised European gas market: Simulation results with a dynamic model

International Nuclear Information System (INIS)

Lise, Wietze; Hobbs, Benjamin F.

2008-01-01

Strategic behaviour by gas producers is likely to affect future gas prices and investments in the European Union (EU). To analyse this issue, a computational game theoretic model is presented that is based on a recursive-dynamic formulation. This model addresses interactions among demand, supply, pipeline and liquefied natural gas (LNG) transport, storage and investments in the natural gas market over the period 2005-2030. Three market scenarios are formulated to study the impact of producer market power. In addition, tradeoffs among investments in pipelines, LNG liquefaction and regasification facilities, and storage are explored. The model runs indicate that LNG can effectively compete with pipelines in the near future. Further, significant decreases in Cournot prices between 2005 and 2010 indicate that near-term investments in EU gas transport capacity are likely to diminish market power by making markets more accessible. (author)

Dynamics of exciplex formation in rare gas media

Energy Technology Data Exchange (ETDEWEB)

Rojas-Lorenzo, German, E-mail: grojas37@gmail.com [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba)] [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rubayo-Soneira, Jesus [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba); Alberti, Sebastian Fernandez [Centro de Estudios e Investigaciones, Universidad Nacional de Quilmes, Roque Saenz Pena 180, Bernal B1876BXD (Argentina)

2009-07-30

A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ({sup 1}S{sub 0} {yields} {sup 3}P{sub 1}) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its {sup 3}P{sub 1} electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg{sup *}-Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

Dynamic performance of power generation systems for off-shore oil and gas platforms

DEFF Research Database (Denmark)

Pierobon, Leonardo; Breuhaus, Peter; Haglind, Fredrik

2014-01-01

%) arises on the prediction of the rotational speed of the high pressure shaft, while the largest deviation (average relative error ~20%) occurs in the evaluation of the pressure at the outlet of the low pressure turbine. As waste heat recovery units (e.g. organic Rankine cycles) are likely...... to be implemented in future off-shore platforms, the proposed model may serve in the design phase for a preliminary assessment of the dynamic response of the power generation system and to evaluate if requirements such as minimum and maximum frequency during transient operation and the recovery time are satisfied......On off-shore oil and gas platforms two or more gas turbines typically support the electrical demand on site by operating as a stand-alone (island) power system. As reliability and availability are major concerns during operation, the dynamic performance of the power generation system becomes...

Incineration and flue gas treatment technologies

International Nuclear Information System (INIS)

1997-01-01

The proceedings are presented of an international symposium on Incineration and Flue Gas Treatment Technologies, held at Sheffield University in July 1997. Papers from each of the six sessions cover the behaviour of particles in incinerator clean-up systems, pollution control technologies, the environmental performance of furnaces and incinerators, controlling nitrogen oxide emissions, separation processes during flue gas treatment and regulatory issues relating to these industrial processes. (UK)

Dynamic Contraction of the Positive Column of a Self-Sustained Glow Discharge in Molecular Gas Flow

Science.gov (United States)

Shneider, Mikhail

2014-10-01

Contraction of the gas discharge, when current contracts from a significant volume of weakly ionized plasma into a thin arc channel, was attracted attention of scientists for more than a century. Studies of the contraction (also called constriction) mechanisms, besides carrying interesting science, are of practical importance, especially when contraction should be prevented. A set of time-dependent two-dimensional equations for the non-equilibrium weakly-ionized nitrogen/ air plasma is formulated. The process is described by a set of time-dependent continuity equations for the electrons, positive and negative ions; gas and vibrational temperature; by taking into account the convective heat and plasma losses by the transverse flux. Transition from the uniform to contracted state was analyzed. It was shown that such transition experiences a hysteresis, and that the critical current of the transition increases when the pressure (gas density) drops. Possible coexistence of the contracted and uniform state of the plasma in the discharge where the current flows along the density gradient of the background gas was discussed. In this talk the problems related to the dynamic contraction of the current channel inside a quasineutral positive column of a self-sustained glow discharge in molecular gas in a rectangular duct with convection cooling will be discussed. Study presented in this talk was stimulated by the fact that there are large number of experiments on the dynamic contraction of a glow discharge in nitrogen and air flows and a many of possible applications. Similar processes play a role in the powerful gas-discharge lasers. In addition, the problem of dynamic contraction in the large volume of non-equilibrium weakly ionized plasma is closely related to the problem of streamer to leader transitions in lightning and blue jets.

Gas attack

Energy Technology Data Exchange (ETDEWEB)

North, D.

1977-08-01

Consumersfirst Ltd. is reacting to deregulation with a massive advertising campaign. The gas utility is owned by Consumers Gas Energy Inc., and is struggling to hold onto its 35 per cent share of Ontario`s two million residential natural gas buyers. An industry analyst pointed out that deregulation could mean that Consumers` Gas has much to lose: customers, market share, control of the assets and control of the process. The Ontario Energy Board (OEB) however, had specified that Consumersfirst is not to proceed with paperwork to sign up new customers until the OEB issues a draft code-of-conduct that would prevent cross-subsidizing between regulated franchise holders. This has now been done, and several heavyweights such as Calgary-based Suncor Energy Inc., Union Gas of Chatham, Ontario, and the US-based Enron Corp. of Houston, have started campaigns to sign up potential consumers. It is predicted that brand loyalty will be a factor, but in the end, like long distance telephone rates, it will all come down to pricing, and a winning formula is not easy to find.

Greenhouse gas emissions trading and project-based mechanisms. Proceedings - CATEP

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-01-01

Greenhouse gas emissions trading and project-based mechanisms for greenhouse gas reduction are emerging market-based instruments for climate change policy. This book presents a selection of papers from an international workshop co-sponsored by the OECD and Concerted Action on Tradeable Emissions Permits (CATEP), to discuss key research and policy issues relating to the design and implementation of these instruments. The papers cover the experience of developing and transition countries with greenhouse gas emissions trading and project-based mechanisms. In addition, the papers examine the use of tradeable permits in policy mixes and harmonisation of emissions trading schemes, as well as transition issues relating to greenhouse gas emissions trading markets.

Study of Influencing Factors of Dynamic Measurements Based on SnO2 Gas Sensor

Directory of Open Access Journals (Sweden)

Jinhuai Liu

2004-08-01

Full Text Available Abstract: The gas-sensing behaviour based on a dynamic measurement method of a single SnO2 gas sensor was investigated by comparison with the static measurement. The influencing factors of nonlinear response such as modulation temperature, duty ratio, heating waveform (rectangular, sinusoidal, saw-tooth, pulse, etc. were also studied. Experimental data showed that temperature was the most essential factor because the changes of frequency and heating waveform could result in the changes of temperature essentially.

Proceedings of the symposium on the many facets of heavy ion fusion reactions

International Nuclear Information System (INIS)

1986-01-01

The topics of the symposium are sub- and near-barrier fusion, limitations to fusion, compound nucleus decay and spectroscopy, incomplete fusion processes, and fragmentation and liquid-gas phase transition. Separate abstracts were prepared for 54 papers in these proceedings

Micronozzles: 3D numerical structural and gas dynamics modeling, fabrication, and preliminary experimental results

Science.gov (United States)

Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Dolganov, A. G.; Sabadash, V. O.

2001-02-01

The tiny engines, founded on the principle of reactive thrust, are one of most perspective actuators developed by modern micromechanics. These engines can be applied for such apparent problems, as orientation and stabilization of small space objects, but also as local or distributed reactive thrust of new phylum of aerospace objects, for control of boundary layer of flying objects and in series of converting power devices of different purposes. Distinctive features of jet tiny engines are profitability (very large thrust-to-weight ratio) and high (milliseconds) response, which makes them to irreplaceable elements in control systems and, specially, in distributed power generations. These features are provided the minimum sizes, high pressure in working chambers and hypersonic velocity of propulsive jet. Topologically micronozzles are designed as the flat batch devices (3 layers as minimum). The lower and upper layers make flat walls of the nozzle and mainly influence on strength properties of the device. The mean layer reshapes geometry and determines gas dynamic characteristic of the nozzle. A special problem is the opening-up of the combustion-mixture, which is not esteemed in this work. It is necessary to allow for effect of considerable local stresses arising at the expense of static and dynamic loading at design of the jet tiny engines. Thermal gas dynamic processes in the chamber and nozzle determine the values and nature of these stresses, which are hardly studied for the microdevices. The priority is mathematical and experimental simulation of these processes. The most suitable object for initial phase of experimental simulation is the 'cold' engine. The demanded chamber static pressure is formed by external compressed air. In Laboratory of Microtechnology and MicroElectroMechanical Systems a number of such tiny engines with different shapes of the chamber's and the nozzles' surfaces were designed, made and tested. The engines were produced from photosensing

2017 Gas Congress special

International Nuclear Information System (INIS)

Corbin, Patrick; Ferrier, Jerome; Holleaux, Didier; Vivier, Laurent; Gattaz, Pierre; Delga, Carole; Carenco, Jean-Francois; Sadamori, Keisuke

2017-01-01

This special issue of 'Gaz d'Aujourd'hui' journal is entirely devoted to the 2017 Gas Congress proceedings. The congress was organized in 5 round tables and 12 workshops: Round table 1 - COP 21 2 years after, workshops 1-6: 1 - digital transformation: what are the challenges for the gas sector? 2 - Which actors and what policies to fight against energy insecurity? 3 - Natural gas development: what fiscal signs? 4 - Terrestrial transportation: current situation and prospects; 5 - Consumers' perception of gas; 6 - industrial uses; Round table 2 - Maritime and fluvial LNG perspectives; Round table 3 - Territories, the new decision-makers, workshops 7-12: 7 - What energy regulation for tomorrow? 8 - How to succeed in injecting more and more green gas? 9 - Digital, data and emerging technologies (drones, blockchain..): challenges and applications for gas networks? 10 - Underground storage: a promising infrastructure? 11 - Security of supply: what new cooperation? 12 - Power-to-gas: a new way of energy valorization; Round table 4 - Gas and electricity, winning synergies; Round table 5 - The Europe of gas

Proceedings - Alternate Fuels II: The disposal and productive use of industrial wastes

International Nuclear Information System (INIS)

Anon.

1991-01-01

The proceedings contain 26 papers dealing with the following topics: fuels (biomass, coal, petroleum coke, landfill gas, hazardous and toxic wastes, liquid wastes, and digester gas); combustion systems; plant systems (pollution control, combustion control, and materials handling systems); external factors (public relations, markets, hazardous waste, vitrification for waste management); and case histories of resource recovery facilities, process heating plants, and retrofits to alternative fuels. All papers have been processed separately for inclusion on the data base

Gas dynamics an introduction with examples from astrophysics and geophysics

CERN Document Server

Achterberg, Abraham

2016-01-01

This book lays the foundations of gas- and fluid dynamics. The basic equations are developed from first principles, building on the (assumed) knowledge of Classical Mechanics. This leads to the discussion of the mathematical properties of flows, conservation laws, perturbation analysis, waves and shocks. Most of the discussion centers on ideal (frictionless) fluids and gases. Viscous flows are discussed when considering flows around obstacles and shocks. Many of the examples used to illustrate various processes come from astrophysics and geophysical phenomena.

On a non-local gas dynamics like integrable hierarchy

International Nuclear Information System (INIS)

Brunelli, Jose Carlos; Das, Ashok

2004-01-01

We study a new hierarchy of equations derived from the system of isentropic gas dynamics equations where the pressure is a non-local function of the density. We show that the hierarchy of equations is integrable. We construct the two compatible Hamiltonian structures and show that the first structure has three distinct Casimirs while the second has one. The existence of Casimirs allows us to extend the flows to local ones. We construct an infinite series of commuting local Hamiltonians as well as three infinite series (related to the three Casimirs) of non-local charges. We discuss the zero curvature formulation of the system where we obtain a simple expression for the non-local conserved charges, which also clarifies the existence of the three series from a Lie algebraic point of view. We point out that the non-local hierarchy of Hunter-Zheng equations can be obtained from our non-local flows when the dynamical variables are properly constrained. (author)

Proceedings of the switched power workshop

International Nuclear Information System (INIS)

Fernow, R.C.

1988-01-01

These proceedings contain most of the presentations given at a workshop on the current state of research in techniques for switched power acceleration. The proceedings are divided, as was the workshop itself, into two parts. Part 1, contains the latest results from a number of groups active in switched power research. The major topic here is a method for switching externally supplied power onto a transmission line. Advocates for vacuum photodiode switching, solid state switching, gas switching, and synthetic pulse generation are all presented. Other important areas of research described in this section concern: external electrical and laser pulsing systems; the properties of the created electromagnetic pulse; structures used for transporting the electromagnetic pulse to the region where the electron beam is located; and possible applications. Part 2 of the proceedings considers the problem of designing a high brightness electron gun using switched power as the power source. This is an important first step in demonstrating the usefulness of switched power techniques for accelerator physics. In addition such a gun could have immediate practical importance for advanced acceleration studies since the brightness could exceed that of present sources by several orders of magnitude. I would like to take this opportunity to thank Kathleen Tuohy and Patricia Tuttle for their assistance in organizing and running the workshop. Their tireless efforts contribute greatly to a very productive meeting

Proceedings of the DGMK-conference 'Synthesis gas chemistry'. Authors' manuscripts

Energy Technology Data Exchange (ETDEWEB)

Hoenicke, D; Kohlpaintner, C; Luecke, B; Reschetilowski, W [eds.

2000-07-01

The main topics of the DGMK-Conference ''Synthesis Gas Chemistry'' were: production of synthesis gas from several educts, new catalysts, Fischer-Tropsch synthesis, hydroformylation, steam reforming and carbonylation.

76 FR 66053 - High Point Gas Transmission, LLC; Notice of Application

Science.gov (United States)

2011-10-25

.... CP12-9-000 pursuant to section 7(c) of the Natural Gas Act and parts 157 and 284 of the Commission's...) approval of its pro forma tariff; and (4) waiver of the segmentation requirement, all as more fully set... other party in the proceeding. Only parties to the proceeding can ask for court review of Commission...

Chaos and The Changing Nature of Science and Medicine. Proceedings

International Nuclear Information System (INIS)

Herbert, D.E.; Croft, P.; Silver, D.S.; Williams, S.G.; Woodall, M.

1996-01-01

These proceedings represent the lectures given at the workshop on chaos and the changing nature of science and medicine. The workshop was sponsored by the University of South Alabama and the American Association of Physicists in Medicine. The topics discussed covered nonlinear dynamical systems, complexity theory, fractals, chaos in biology and medicine and in fluid dynamics. Applications of chaotic dynamics in climatology were also discussed. There were 8 lectures at the workshop and all 8 have been abstracted for the Energy Science and Technology database

Gas hydrates:estimation of the gas potential, from reflection seismic data in the continental shelf of Uruguay

International Nuclear Information System (INIS)

De Santa Ana, H.; Ucha, N.; Gutierrez, L.; Veroslavsky, G.

2004-01-01

The uruguayan continental shelf shows geophysical indicators of gas hydrates in the Oriental del Plata, Pelotas and Punta del Este basin. The aim of this work is to present the potential presence of gas at the continental shelf in Uruguay and to evaluate the possibility of exploration of unconventional hydrocarbon plays. Analysis of the seismic surface based on regional and stratgigraphic information that proceeded from previous hydrocarbon exploration in the area have been used to estimatge resources of gas hydrates. Gas hydrates accumulation was mapped using characteristic reflectors and amplitude anomalies of seismic lines (BSR). Its quantity was estimated on this basis in about 86 TCF.

Uncertainty in microscale gas damping: Implications on dynamics of capacitive MEMS switches

International Nuclear Information System (INIS)

Alexeenko, Alina; Chigullapalli, Sruti; Zeng Juan; Guo Xiaohui; Kovacs, Andrew; Peroulis, Dimitrios

2011-01-01

Effects of uncertainties in gas damping models, geometry and mechanical properties on the dynamics of micro-electro-mechanical systems (MEMS) capacitive switch are studied. A sample of typical capacitive switches has been fabricated and characterized at Purdue University. High-fidelity simulations of gas damping on planar microbeams are developed and verified under relevant conditions. This and other gas damping models are then applied to study the dynamics of a single closing event for switches with experimentally measured properties. It has been demonstrated that although all damping models considered predict similar damping quality factor and agree well for predictions of closing time, the models differ by a factor of two and more in predicting the impact velocity and acceleration at contact. Implications of parameter uncertainties on the key reliability-related parameters such as the pull-in voltage, closing time and impact velocity are discussed. A notable effect of uncertainty is that the nominal switch, i.e. the switch with the average properties, does not actuate at the mean actuation voltage. Additionally, the device-to-device variability leads to significant differences in dynamics. For example, the mean impact velocity for switches actuated under the 90%-actuation voltage (about 150 V), i.e. the voltage required to actuate 90% of the sample, is about 129 cm/s and increases to 173 cm/s for the 99%-actuation voltage (of about 173 V). Response surfaces of impact velocity and closing time to five input variables were constructed using the Smolyak sparse grid algorithm. The sensitivity analysis showed that impact velocity is most sensitive to the damping coefficient whereas the closing time is most affected by the geometric parameters such as gap and beam thickness. - Highlights: → We examine stochastic non-linear response of a microsystem switch subject to multiple input uncertainties. → Sample devices have been fabricated and device

Large-scale gas dynamical processes affecting the origin and evolution of gaseous galactic halos

Science.gov (United States)

Shapiro, Paul R.

1991-01-01

Observations of galactic halo gas are consistent with an interpretation in terms of the galactic fountain model in which supernova heated gas in the galactic disk escapes into the halo, radiatively cools and forms clouds which fall back to the disk. The results of a new study of several large-scale gas dynamical effects which are expected to occur in such a model for the origin and evolution of galactic halo gas will be summarized, including the following: (1) nonequilibrium absorption line and emission spectrum diagnostics for radiatively cooling halo gas in our own galaxy, as well the implications of such absorption line diagnostics for the origin of quasar absorption lines in galactic halo clouds of high redshift galaxies; (2) numerical MHD simulations and analytical analysis of large-scale explosions ad superbubbles in the galactic disk and halo; (3) numerical MHD simulations of halo cloud formation by thermal instability, with and without magnetic field; and (4) the effect of the galactic fountain on the galactic dynamo.

Insights into the dynamics of in situ gas hydrate formation and dissociation at the Bush Hill gas hydrate field, Gulf of Mexico

Energy Technology Data Exchange (ETDEWEB)

Solomon, Evan A.; Kastner, Miriam; Robertson, Gretchen; Jannasch, Hans; Weinstein, Yishai

2005-07-01

Four newly designed flux meters called the MOSQUITO (Multiple Orifice Sampler and Quantitative Injection Tracer Observer), capable of measuring fluid flow rates and sampling pore fluid chemistry simultaneously, and two temperature loggers were deployed for 430 days adjacent to the Bush Hill hydrate mound in the northern Gulf of Mexico (GC 185). The main objective of the deployment was to understand how chemistry, temperature, and subsurface hydrology dynamically influence the growth and dissociation of the gas hydrate mound. The flux meters were deployed in a mussel field, in bacterial mats, in a tubeworm field, and at a background site approximately 100 m southwest of the hydrate mound. Results from the longterm chemical monitoring suggest that this system is not in dynamic equilibrium. Gas hydrate actively formed within the mussel field adjacent to the most active gas vent, in the tubeworm field, and at the background site. The hydrology is variable with upward flow rates ranging from 1-90 cm/yr and downward flow rates from 3-130 cm/yr. Two distinct hydrologic pulsing events were sampled across the three mound sites, which advect a fluid from depth that further stabilizes the gas hydrate deposit. The hydrogeochemistry at Bush Hill seems to be influenced by multiple mechanisms such as active formation of gas hydrate, fluid influx and outflux due to active venting of CH4 at transient methane seeps at and near the mound, local salt tectonics, and density driven convection. The fluxes of fluid, solutes, and methane may have a significant impact on the seafloor biochemical environment and the water column chemistry at Bush Hill. (Author)

Gas-Dynamic Designing of the Exhaust System for the Air Brake

Science.gov (United States)

Novikova, Yu; Goriachkin, E.; Volkov, A.

2018-01-01

Each gas turbine engine is tested some times during the life-cycle. The test equipment includes the air brake that utilizes the power produced by the gas turbine engine. In actual conditions, the outlet pressure of the air brake does not change and is equal to atmospheric pressure. For this reason, for the air brake work it is necessary to design the special exhaust system. Mission of the exhaust system is to provide the required level of backpressure at the outlet of the air brake. The backpressure is required for the required power utilization by the air brake (the air brake operation in the required points on the performance curves). The paper is described the development of the gas dynamic canal, designing outlet guide vane and the creation of a unified exhaust system for the air brake. Using a unified exhaust system involves moving the operating point to the performance curve further away from the calculated point. However, the applying of one exhaust system instead of two will significantly reduce the cash and time costs.

Furnace draft dynamics analysis after a flue gas desulphurization system incorporation

Energy Technology Data Exchange (ETDEWEB)

Zazo, J.F.L. [Tecnatom, S.A. (Spain)

2007-07-01

Due to environmental regulations some utilities are modifying coal-fired power groups by installing a flue gas desulfurisation system (FGDS) in order to remove SO{sub 2} from a gas stream. These studies have been ordered by 'Endesa Generacion' for the following power plant groups: C.T. Teruel Grs. 1-3, C.T. Litoral Gr. 2, C.T. Compostilla Gr. 3, C.T. Alucdia Grs. 1-2, C.T. Compostilla Grs. 4-5 (on-going); and C.T. Los Barrios (on-going). The pictures that appear in this abstract correspond to Compostilla Gr.4 and Los Barrios projects. In both cases FGDS installation implies a new booster fan and heat exchanger keeping former Induced Draft Fans (IDFs). The main goal for these projects is to analyze the new flue-gas dynamic, in order to: detect risk situations to equipment, particularly to boiler integrity, test control system strategies and interlocks, select parameters to valves and control system to minimize pressure transients, and test operation strategies. 14 figs.

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

Argon concentration time-series as a tool to study gas dynamics in the hyporheic zone.

Science.gov (United States)

Mächler, Lars; Brennwald, Matthias S; Kipfer, Rolf

2013-07-02

The oxygen dynamics in the hyporheic zone of a peri-alpine river (Thur, Switzerland), were studied through recording and analyzing the concentration time-series of dissolved argon, oxygen, carbon dioxide, and temperature during low flow conditions, for a period of one week. The argon concentration time-series was used to investigate the physical gas dynamics in the hyporheic zone. Differences in the transport behavior of heat and gas were determined by comparing the diel temperature evolution of groundwater to the measured concentration of dissolved argon. These differences were most likely caused by vertical heat transport which influenced the local groundwater temperature. The argon concentration time-series were also used to estimate travel times by cross correlating argon concentrations in the groundwater with argon concentrations in the river. The information gained from quantifying the physical gas transport was used to estimate the oxygen turnover in groundwater after water recharge. The resulting oxygen turnover showed strong diel variations, which correlated with the water temperature during groundwater recharge. Hence, the variation in the consumption rate was most likely caused by the temperature dependence of microbial activity.

Dynamics of the Croatian electricity market opening

International Nuclear Information System (INIS)

Pesut, D.; Zeljko, M.; Zutobradic, S.

2003-01-01

Customer eligibility is regulated by the Law on Electricity Market and its Article 23 (Official Gazette 79/01). Eligibility is understood as a possible supplier choice. To ensure the eligible status, annual demand should exceed 40 GWh. The category of customers that has gained the eligibility status based on the Law on Electricity Market makes out a total of around 7 percent of the annual electric energy consumption in Croatia. Thus, it can be said that electricity market openness in Croatia lies somewhat below 10 percent. According to the already mentioned Article 23, paragraph 4, the Government may determine annual demand threshold lowering as a condition to grant the eligibility status. According to the Law on Gas Market from 2001, the category of eligible gas customers in Croatia includes all electricity generators who use gas, regardless of the annual gas consumption, and other customers whose annual consumption exceeds 100 million m3. In 2002 there were seven such customers and they participated with 1,374,160,000 m3, i.e. 51 percent in the total gas consumption. As INA is the sole natural gas producer in Croatia with a long-term contract on the supply line lease for the transportation of Russian gas, it is also the only supplier of natural gas. Therefore, in 2002 each eligible customer bought gas from INA. Issues related to this field are: what kind of dynamics should one proceed with toward further energy market opening in Croatia? How large is this share of electricity, i.e. gas consumption in Croatia? What are the prerequisites, both organisational and technical, for this kind of market opening? (author)

Conference Proceedings

International Nuclear Information System (INIS)

2002-01-01

This volume contains the unedited proceedings of the Second Annual Conference on Managing Electricity Price Volatility. There were a total of eleven papers presented, dealing with a variety of issues affecting price volatility. Subjects treated included: new power generation development in Alberta; an analysis of electricity supply and demand to predict future price volatility; the effect of government intervention in the Alberta electricity market; risk management in volatile energy markets; an analysis of Alberta's capacity to supply its own internal electric power needs; the impact of increased electricity import and export capacity on price fluctuation in Alberta; improving market liquidity in Alberta; using weather derivatives to offset price risk; the impact of natural gas prices on electricity price volatility; capitalizing on advancements in online trading; and strategies for businesses to keep operating through times of price volatility. In most cases only overhead viewgraphs are available

Dynamics of gas cell coalescence during baking expansion of leavened dough.

Science.gov (United States)

Miś, Antoni; Nawrocka, Agnieszka; Lamorski, Krzysztof; Dziki, Dariusz

2018-01-01

The investigation of the dynamics of gas cell coalescence, i.e. a phenomenon that deteriorates the homogeneity of the cellular structure of bread crumb, was carried out performing simultaneously measurements of the dough volume, pressure, and viscosity. It was demonstrated that, during the baking expansion of chemically leavened wheat flour dough, the maximum growth rate of the gas cell radius determined from the ratio of pressure exerted by the expanded dough to its viscosity was on average four-fold lower than that calculated from volume changes in the gas phase of the dough. Such a high discrepancy was interpreted as a result of the course of coalescence, and a formula for determination of its rate was developed. The coalescence rate in the initial baking expansion phase had negative values, indicating nucleation of newly formed gas cells, which increased the number of gas cells even by 8%. In the next baking expansion phase, the coalescence rate started to exhibit positive values, reflecting dominance of the coalescence phenomenon over nucleation. The maximum coalescence rates indicate that, during the period of the most intensive dough expansion, the number of gas cells decreased by 2-3% within one second. At the end of the formation of bread crumb, the number of the gas cells declined by 55-67% in comparison with the initial value. The correctness of the results was positively verified using X-ray micro-computed tomography. The developed method can be a useful tool for more profound exploration of the coalescence phenomenon at various stages of evolution of the cellular structure and its determinants, which may contribute to future development of more effective methods for improving the texture and sensory quality of bread crumb. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular theory of mass transfer kinetics and dynamics at gas-water interface

International Nuclear Information System (INIS)

Morita, Akihiro; Garrett, Bruce C

2008-01-01

The mass transfer mechanism across gas-water interface is studied with molecular dynamics (MD) simulation. The MD results provide a robust and qualitatively consistent picture to previous studies about microscopic aspects of mass transfer, including interface structure, free energy profiles for the uptake, scattering dynamics and energy relaxation of impinging molecules. These MD results are quantitatively compared with experimental uptake measurements, and we find that the apparent inconsistency between MD and experiment could be partly resolved by precise decomposition of the observed kinetics into elemental steps. Remaining issues and future perspectives toward constructing a comprehensive multi-scale description of interfacial mass transfer are summarized.

Effect of differences in gas-dynamic behaviour on the separation performance of ultracentrifuges connected in parallel

International Nuclear Information System (INIS)

Portoghese, C.C.P.; Buchmann, J.H.

1996-01-01

This paper is concerned with the degradation of separation factors occurred when groups of ultracentrifuges having different gas-dynamic behaviour are connected in parallel arrangements. Differences in the gas-dynamic behavior were traduced in terms of different tails pressures for the same operational conditions, that are feed flow rate, product pressure and cut number. A mathematical model describing the ratio of the tails flow rates as a function of the tails pressure ratios and the feed flow rate was developed using experimental data collected from a pair of different ultracentrifuges connected in parallel. The optimization of model parameters was made using Marquardt's algorithm. The model developed was used to simulate the separation factors degradation in some parallel arrangements containing more than two centrifuges. Te obtained results were compared with experimental data collected from different groups of ultracentrifuges. It was observed that the calculated results were in good agreement with experimental data. This mathematical model, which parameters were determined in a two-centrifuges parallel arrangement, is useful to simulate the effect of quantified gas-dynamic differences in the separation factors of groups containing any number of different ultracentrifuges and, consequently, to analyze cascade losses due to this kind of occurrence. (author)

Collective nuclear dynamics. Proceedings

International Nuclear Information System (INIS)

Ivanyuk, F.A.

1994-01-01

The Fourth International school on nuclear physics was help on 29 Aug - 7 Sep, 1994 in Ukraine. The specialists discussed following subjects:liquid drop and the shell correction method; nuclear deformation energy and fission; nuclear structure at high spins, superdeformed states, structure of excited and exotic nuclei; nuclear fluid dynamics and large scale collective motion; order and chaos as they relate to the collective motion; quantum and interference phenomena in nuclear collisions; quasi-fission and multinucleon fragmentation effects; shell effects in non-nuclear systems; new nuclear facilities

Collective nuclear dynamics. Proceedings.

Energy Technology Data Exchange (ETDEWEB)

Ivanyuk, F A [eds.

1994-12-31

The Fourth International school on nuclear physics was help on 29 Aug - 7 Sep, 1994 in Ukraine. The specialists discussed following subjects:liquid drop and the shell correction method; nuclear deformation energy and fission; nuclear structure at high spins, superdeformed states, structure of excited and exotic nuclei; nuclear fluid dynamics and large scale collective motion; order and chaos as they relate to the collective motion; quantum and interference phenomena in nuclear collisions; quasi-fission and multinucleon fragmentation effects; shell effects in non-nuclear systems; new nuclear facilities.

Hydrodynamic performance of a single-use aerated stirred bioreactor in animal cell culture: applications of tomography, dynamic gas disengagement (DGD), and CFD.

Science.gov (United States)

Kazemzadeh, Argang; Elias, Cynthia; Tamer, Melih; Ein-Mozaffari, Farhad

2018-05-01

The hydrodynamics of gas-liquid two-phase flow in a single-use bioreactor were investigated in detail both experimentally and numerically. Electrical resistance tomography (ERT) and dynamic gas disengagement (DGD) combined with computational fluid dynamics (CFD) were employed to assess the effect of the volumetric gas flow rate and impeller speed on the gas-liquid flow field, local and global gas holdup values, and Sauter mean bubble diameter. From the results obtained from DGD coupled with ERT, the bubble sizes were determined. The experimental data indicated that the total gas holdup values increased with increasing both the rotational speed of impeller and volumetric gas flow rate. Moreover, the analysis of the flow field generated inside the aerated stirred bioreactor was conducted using CFD results. Overall, a more uniform distribution of the gas holdup was obtained at impeller speeds ≥ 100 rpm for volumetric gas flow rates ≥ 1.6 × 10 -5  m 3 /s.

Shock structure in continuum models of gas dynamics: stability and bifurcation analysis

International Nuclear Information System (INIS)

Simić, Srboljub S

2009-01-01

The problem of shock structure in gas dynamics is analysed through a comparative study of two continuum models: the parabolic Navier–Stokes–Fourier model and the hyperbolic system of 13 moments equations modeling viscous, heat-conducting monatomic gases within the context of extended thermodynamics. When dissipative phenomena are neglected these models both reduce to classical Euler's equations of gas dynamics. The shock profile solution, assumed in the form of a planar travelling wave, reduces the problem to a system of ordinary differential equations, and equilibrium states appear to be stationary points of the system. It is shown that in both models an upstream equilibrium state suffers an exchange of stability when the shock speed crosses the critical value which coincides with the highest characteristic speed of the Euler's system. At the same time a downstream equilibrium state could be seen as a steady bifurcating solution, while the shock profile represents a heteroclinic orbit connecting the two stationary points. Using centre manifold reduction it is demonstrated that both models, although mathematically different, obey the same transcritical bifurcation pattern in the neighbourhood of the bifurcation point corresponding to the critical value of shock speed, the speed of sound

Coal liquefaction and gas conversion: Proceedings. Volume 1

Energy Technology Data Exchange (ETDEWEB)

1993-12-31

Volume I contains papers presented at the following sessions: AR-Coal Liquefaction; Gas to Liquids; and Direct Liquefaction. Selected papers have been processed separately for inclusion in the Energy Science and Technology Database.

16th DOE nuclear air cleaning conference: proceedings

International Nuclear Information System (INIS)

First, M.W.

1981-02-01

Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas: treatment of offgases from chemical processing; aerosol; behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions; HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration; filter testing; and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

16th DOE nuclear air cleaning conference: proceedings

International Nuclear Information System (INIS)

First, M.W.

1981-02-01

Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas; treatment of offgases from chemical processing; aerosol behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions: HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration, filter testing, and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro/nano-channel : heat flux predictions using combined molecular dynamics and Monte Carlo techniques

NARCIS (Netherlands)

Gaastra - Nedea, S.V.; Steenhoven, van A.A.; Markvoort, A.J.; Spijker, P.; Giordano, D.

2014-01-01

The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and

The Mexican energy sector: integrated dynamic analysis of the natural gas/refining system

International Nuclear Information System (INIS)

Barnes-Regueiro, Francisco; Leach, Matthew; Ruth, Matthias

2002-01-01

Environmental regulations in Mexico could dramatically increase demand for natural gas in the following years. This increase could lead to gas price shocks and a counter-intuitive increase in carbon emissions. The effect would be accentuated if Mexico lacks the funds required to carry on with investments in gas development and processing capacity. With the use of a dynamic computer model, this study addresses responses of the Mexican oil and gas industries to perturbations such as: changes in regulatory and environmental policies; changes in institutional arrangements such as those arising from market liberalization; and lack of availability of investment funds. The study also assesses how regulatory policies can be designed to minimize the economic inefficiencies arising from the business cycle disruptions that some perturbations may cause. In addition, this study investigates how investment responses will shape the Mexican energy sector in the future, particularly with respect to both the relative importance of different fuels for power generation and heating purposes and the nature of competition in the Mexican natural gas market. Furthermore, this study explores the direct consequences of these responses on the level of carbon emissions. (Author)

The wet compression technology for gas turbine power plants: Thermodynamic model

International Nuclear Information System (INIS)

Bracco, Stefano; Pierfederici, Alessandro; Trucco, Angela

2007-01-01

This paper examines from a thermodynamic point of view the effects of wet compression on gas turbine power plants, particularly analysing the influence of ambient conditions on the plant performance. The results of the mathematical model, implemented in 'Matlab' software, have been compared with the simulation results presented in literature and in particular the values of the 'evaporative rate', proposed in Araimo et al. [L. Araimo, A. Torelli, Thermodynamic analysis of the wet compression process in heavy duty gas turbine compressors, in: Proceedings of the 59th ATI Annual Congress, Genova, 2004, pp. 1249-1263; L. Araimo, A. Torelli, Wet compression technology applied to heavy duty gas turbines - GT power augmentation and efficiency upgrade, in: Proceedings of the 59th ATI Annual Congress, Genova, 2004, pp. 1265-1277] by 'Gas Turbines Department' of Ansaldo Energia S.p.A., have been taken into account to validate the model. The simulator permits to investigate the effects of the fogging and wet compression techniques and estimate the power and efficiency gain of heavy duty gas turbines operating in hot and arid conditions

New Iterative Method for Fractional Gas Dynamics and Coupled Burger’s Equations

Directory of Open Access Journals (Sweden)

Mohamed S. Al-luhaibi

2015-01-01

Full Text Available This paper presents the approximate analytical solutions to solve the nonlinear gas dynamics and coupled Burger’s equations with fractional time derivative. By using initial values, the explicit solutions of the equations are solved by using a reliable algorithm. Numerical results show that the new iterative method is easy to implement and accurate when applied to time-fractional partial differential equations.

Vorticity and symplecticity in multi-symplectic, Lagrangian gas dynamics

Science.gov (United States)

Webb, G. M.; Anco, S. C.

2016-02-01

The Lagrangian, multi-dimensional, ideal, compressible gas dynamic equations are written in a multi-symplectic form, in which the Lagrangian fluid labels, m i (the Lagrangian mass coordinates) and time t are the independent variables, and in which the Eulerian position of the fluid element {x}={x}({m},t) and the entropy S=S({m},t) are the dependent variables. Constraints in the variational principle are incorporated by means of Lagrange multipliers. The constraints are: the entropy advection equation S t = 0, the Lagrangian map equation {{x}}t={u} where {u} is the fluid velocity, and the mass continuity equation which has the form J=τ where J={det}({x}{ij}) is the Jacobian of the Lagrangian map in which {x}{ij}=\\partial {x}i/\\partial {m}j and τ =1/ρ is the specific volume of the gas. The internal energy per unit volume of the gas \\varepsilon =\\varepsilon (ρ ,S) corresponds to a non-barotropic gas. The Lagrangian is used to define multi-momenta, and to develop de Donder-Weyl Hamiltonian equations. The de Donder-Weyl equations are cast in a multi-symplectic form. The pullback conservation laws and the symplecticity conservation laws are obtained. One class of symplecticity conservation laws give rise to vorticity and potential vorticity type conservation laws, and another class of symplecticity laws are related to derivatives of the Lagrangian energy conservation law with respect to the Lagrangian mass coordinates m i . We show that the vorticity-symplecticity laws can be derived by a Lie dragging method, and also by using Noether’s second theorem and a fluid relabelling symmetry which is a divergence symmetry of the action. We obtain the Cartan-Poincaré form describing the equations and we discuss a set of differential forms representing the equation system.

Dynamical analysis of an n‑H‑T cosmological quintessence real gas model with a general equation of state

Science.gov (United States)

Ivanov, Rossen I.; Prodanov, Emil M.

2018-01-01

The cosmological dynamics of a quintessence model based on real gas with general equation of state is presented within the framework of a three-dimensional dynamical system describing the time evolution of the number density, the Hubble parameter and the temperature. Two global first integrals are found and examples for gas with virial expansion and van der Waals gas are presented. The van der Waals system is completely integrable. In addition to the unbounded trajectories, stemming from the presence of the conserved quantities, stable periodic solutions (closed orbits) also exist under certain conditions and these represent models of a cyclic Universe. The cyclic solutions exhibit regions characterized by inflation and deflation, while the open trajectories are characterized by inflation in a “fly-by” near an unstable critical point.

Molecular dynamics simulations of classical sound absorption in a monatomic gas

Science.gov (United States)

Ayub, M.; Zander, A. C.; Huang, D. M.; Cazzolato, B. S.; Howard, C. Q.

2018-05-01

Sound wave propagation in argon gas is simulated using molecular dynamics (MD) in order to determine the attenuation of acoustic energy due to classical (viscous and thermal) losses at high frequencies. In addition, a method is described to estimate attenuation of acoustic energy using the thermodynamic concept of exergy. The results are compared against standing wave theory and the predictions of the theory of continuum mechanics. Acoustic energy losses are studied by evaluating various attenuation parameters and by comparing the changes in behavior at three different frequencies. This study demonstrates acoustic absorption effects in a gas simulated in a thermostatted molecular simulation and quantifies the classical losses in terms of the sound attenuation constant. The approach can be extended to further understanding of acoustic loss mechanisms in the presence of nanoscale porous materials in the simulation domain.

Thermal fluid dynamic behavior of coolant helium gas in a typical reactor VHTGR channel of prismatic core

International Nuclear Information System (INIS)

Belo, Allan Cavalcante

2016-01-01

The current studies about the thermal fluid dynamic behavior of the VHTGR core reactors of 4 th generation are commonly developed in 3-D analysis in CFD (computational fluid dynamics), which often requires considerable time and complex mathematical calculations for carrying out these analysis. The purpose of this project is to achieve thermal fluid dynamic analysis of flow of gas helium refrigerant in a typical channel of VHTGR prismatic core reactor evaluating magnitudes of interest such as temperature, pressure and fluid velocity and temperature distribution in the wall of the coolant channel from the development of a computer code in MATLAB considering the flow on one-dimensional channel, thereby significantly reducing the processing time of calculations. The model uses three different references to the physical properties of helium: expressions given by the KTA (German committee of nuclear safety standards), the computational tool REFPROP and a set of constant values for the entire channel. With the use of these three references it is possible to simulate the flow treating the gas both compressible and incompressible. The results showed very close values for the interest quantities and revealed that there are no significant differences in the use of different references used in the project. Another important conclusion to be observed is the independence of helium in the gas compressibility effects on thermal fluid dynamic behavior. The study also indicated that the gas undergoes no severe effects due to high temperature variations in the channel, since this goes in the channel at 914 K and exits at approximately 1263 K, which shows the excellent use of helium as a refrigerant fluid in reactor channels VHTGR. The comparison of results obtained in this work with others in the literature served to confirm the effectiveness of the one-dimensional consideration of method of gas flow in the coolant channel to replace the models made in 3-D for the pressure range and

Dynamic performance of a combined gas turbine and air bottoming cycle plant for off-shore applications

DEFF Research Database (Denmark)

Benato, Alberto; Pierobon, Leonardo; Haglind, Fredrik

2014-01-01

and a combined gas turbine coupled with an air bottoming cycle plant. The case study is the Draugen off-shore oil and gas platform, located in the North Sea, Norway. The normal electricity demand is 19 MW, currently covered by two gas turbines generating each 50% of the power demand, while the third turbine......When the Norwegian government introduced the CO2 tax for hydrocarbon fuels, the challenge became to improve the performance of off-shore power systems. An oil and gas platform typically operates on an island (stand-alone system) and the power demand is covered by two or more gas turbines. In order...... to improve the plant performance, a bottoming cycle unit can be added to the gas turbine topping module, thus constituting a combined cycle plant. This paper aims at developing and testing the numerical model simulating the part-load and dynamic behavior of a novel power system, composed of two gas turbines...

Proceedings of the 6. international conference on gas hydrates : ICGH 2008

Energy Technology Data Exchange (ETDEWEB)

Englezos, P. (ed.) [British Columbia Univ., Vancouver, BC (Canada); Ripmeester, J. (ed.) [National Research Council of Canada, Ottawa, ON (Canada); Dallimore, S.R. [Natural Resources Canada, Ottawa, ON (Canada). Geological Survey of Canada; Servio, P. [McGill Univ., Montreal, PQ (Canada). Dept. of Chemical Engineering; Austvik, T. [Statoil, Trondheim (Norway); Collett, T.S. [United States Geological Survey, Denver, CO (United States); Mehta, A. [Shell E and P Asia Pacific, Sarawak (Malaysia); Paull, C.K. [Monterey Bay Aquarium Research Inst., CA (United States); Sloan, E.D.Jr. [Colorado School of Mines, Golden, CO (United States); Uchida, T. [Hokkaido Univ., Sapporo (Japan)] (comps.)

2008-07-01

This international conference provided a forum to highlight gas hydrate research that is underway at academic institutions as well as government and industrial laboratories around the world. The gas or clathrate hydrate research community includes chemical, petroleum and mechanical engineers, geologists, geophysicists, marine biologists, chemists and physicists. The conference was attended by more than 500 delegates who presented their professional knowledge in all areas of the gas hydrates field, emphasizing new aspects. The topics of discussion included resource delineation, reservoir simulation modeling and production technology. Environmental considerations involving natural gas hydrates and global climate change were also highlighted along with carbon dioxide disposal in aquifers and deep oceans. Issues facing oil and gas operations were also discussed, with reference to flow assurance in pipelines, safety issues, permafrost and marine geohazards. Novel technologies involving hydrogen storage, carbon dioxide capture and sequestration were also highlighted along with basic science and engineering aspects of gas hydrate systems. All 417 presentations from the conference have been catalogued separately for inclusion in this database. refs., tabs., figs.

Proceedings of the 6. international conference on gas hydrates : ICGH 2008

International Nuclear Information System (INIS)

Englezos, P.; Ripmeester, J.; Dallimore, S.R.; Collett, T.S.; Mehta, A.; Paull, C.K.; Sloan, E.D.Jr.; Uchida, T.

2008-01-01

This international conference provided a forum to highlight gas hydrate research that is underway at academic institutions as well as government and industrial laboratories around the world. The gas or clathrate hydrate research community includes chemical, petroleum and mechanical engineers, geologists, geophysicists, marine biologists, chemists and physicists. The conference was attended by more than 500 delegates who presented their professional knowledge in all areas of the gas hydrates field, emphasizing new aspects. The topics of discussion included resource delineation, reservoir simulation modeling and production technology. Environmental considerations involving natural gas hydrates and global climate change were also highlighted along with carbon dioxide disposal in aquifers and deep oceans. Issues facing oil and gas operations were also discussed, with reference to flow assurance in pipelines, safety issues, permafrost and marine geohazards. Novel technologies involving hydrogen storage, carbon dioxide capture and sequestration were also highlighted along with basic science and engineering aspects of gas hydrate systems. All 417 presentations from the conference have been catalogued separately for inclusion in this database. refs., tabs., figs

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.

PREFACE: 1st European Conference on Gas Micro Flows (GasMems 2012)

Science.gov (United States)

Frijns, Arjan; Valougeorgis, Dimitris; Colin, Stéphane; Baldas, Lucien

2012-05-01

The aim of the 1st European Conference on Gas Micro Flows is to advance research in Europe and worldwide in the field of gas micro flows as well as to improve global fundamental knowledge and to enable technological applications. Gas flows in microsystems are of great importance and touch almost every industrial field (e.g. fluidic microactuators for active control of aerodynamic flows, vacuum generators for extracting biological samples, mass flow and temperature micro-sensors, pressure gauges, micro heat-exchangers for the cooling of electronic components or for chemical applications, and micro gas analyzers or separators). The main characteristic of gas microflows is their rarefaction, which for device design often requires modelling and simulation both by continuous and molecular approaches. In such flows various non-equilibrium transport phenomena appear, while the role played by the interaction between the gas and the solid device surfaces becomes essential. The proposed models of boundary conditions often need an empirical adjustment strongly dependent on the micro manufacturing technique. The 1st European Conference on Gas Micro Flows is organized under the umbrella of the recently established GASMEMS network (www.gasmems.eu/) consisting of 13 participants and six associate members. The main objectives of the network are to structure research and train researchers in the fields of micro gas dynamics, measurement techniques for gaseous flows in micro experimental setups, microstructure design and micro manufacturing with applications in lab and industry. The conference takes place on June 6-8 2012, at the Skiathos Palace Hotel, on the beautiful island of Skiathos, Greece. The conference has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement ITN GASMEMS no. 215504. It owes its success to many people. We would like to acknowledge the support of all members of the Scientific Committee and of all

Gas Price Formation, Structure and Dynamics

Energy Technology Data Exchange (ETDEWEB)

Davoust, R.

2008-07-01

Our study, focused on gas prices in importing economies, describes wholesale prices and retail prices, their evolution for the last one or two decades, the economic mechanisms of price formation. While an international market for oil has developed thanks to moderate storage and transportation charges, these costs are much higher in the case of natural gas, which involves that this energy is still traded inside continental markets. There are three regional gas markets around the world: North America (the United States, importing mainly from Canada and Mexico), Europe (importing mainly from Russia, Algeria and Norway) and Asia (Japan, Korea, Taiwan, China and India, importing mainly from Indonesia, Malaysia and Australia). A market for gas has also developed in South America, but it will not be covered by our paper. In Europe and the US, due to large domestic resources and strong grids, natural gas is purchased mostly through pipelines. In Northeast Asia, there is a lack of such infrastructures, so imported gas takes mainly the form of Liquefied Natural Gas (LNG), shipped on maritime tankers. Currently, the LNG market is divided into two zones: the Atlantic Basin (Europe and US) and the Pacific Basin (Asia and the Western Coast of America). For the past few years, the Middle East and Africa have tended to be crucial suppliers for both LNG zones. Gas price formation varies deeply between regional markets, depending on several structural factors (regulation, contracting practises, existence of a spot market, liquidity, share of imports). Empirically, the degree of market opening (which corresponds to the seniority in the liberalization process) seems to be the primary determinant of pricing patterns. North America has the most liberalized and well-performing natural gas industry in the world. Gas pricing is highly competitive and is based on supply/demand balances. Spot and futures markets are developed. The British gas sector is also deregulated and thus follows a

Gas Price Formation, Structure and Dynamics

International Nuclear Information System (INIS)

Davoust, R.

2008-01-01

Our study, focused on gas prices in importing economies, describes wholesale prices and retail prices, their evolution for the last one or two decades, the economic mechanisms of price formation. While an international market for oil has developed thanks to moderate storage and transportation charges, these costs are much higher in the case of natural gas, which involves that this energy is still traded inside continental markets. There are three regional gas markets around the world: North America (the United States, importing mainly from Canada and Mexico), Europe (importing mainly from Russia, Algeria and Norway) and Asia (Japan, Korea, Taiwan, China and India, importing mainly from Indonesia, Malaysia and Australia). A market for gas has also developed in South America, but it will not be covered by our paper. In Europe and the US, due to large domestic resources and strong grids, natural gas is purchased mostly through pipelines. In Northeast Asia, there is a lack of such infrastructures, so imported gas takes mainly the form of Liquefied Natural Gas (LNG), shipped on maritime tankers. Currently, the LNG market is divided into two zones: the Atlantic Basin (Europe and US) and the Pacific Basin (Asia and the Western Coast of America). For the past few years, the Middle East and Africa have tended to be crucial suppliers for both LNG zones. Gas price formation varies deeply between regional markets, depending on several structural factors (regulation, contracting practises, existence of a spot market, liquidity, share of imports). Empirically, the degree of market opening (which corresponds to the seniority in the liberalization process) seems to be the primary determinant of pricing patterns. North America has the most liberalized and well-performing natural gas industry in the world. Gas pricing is highly competitive and is based on supply/demand balances. Spot and futures markets are developed. The British gas sector is also deregulated and thus follows a

Dynamic structure factor of the normal Fermi gas from the collisionless to the hydrodynamic regime

International Nuclear Information System (INIS)

Watabe, Shohei; Nikuni, Tetsuro

2010-01-01

The dynamic structure factor of a normal Fermi gas is investigated by using the moment method for the Boltzmann equation. We determine the spectral function at finite temperatures over the full range of crossover from the collisionless regime to the hydrodynamic regime. We find that the Brillouin peak in the dynamic structure factor exhibits a smooth crossover from zero to first sound as functions of temperature and interaction strength. The dynamic structure factor obtained using the moment method also exhibits a definite Rayleigh peak (ω∼0), which is a characteristic of the hydrodynamic regime. We compare the dynamic structure factor obtained by the moment method with that obtained from the hydrodynamic equations.

Gas-particle interactions in dense gas-fluidised beds

NARCIS (Netherlands)

Li, J.; Kuipers, J.A.M.

2003-01-01

The occurrence of heterogeneous flow structures in gas-particle flows seriously affects gas¿solid contacting and transport processes in dense gas-fluidized beds. A computational study, using a discrete particle method based on Molecular Dynamics techniques, has been carried out to explore the

Fluctuations in non-ideal pion gas with dynamically fixed particle number

Science.gov (United States)

Kolomeitsev, E. E.; Voskresensky, D. N.

2018-05-01

We consider a non-ideal hot pion gas with the dynamically fixed number of particles in the model with the λϕ4 interaction. The effective Lagrangian for the description of such a system is obtained after dropping the terms responsible for the change of the total particle number. Reactions π+π- ↔π0π0, which determine the isospin balance of the medium, are permitted. Within the self-consistent Hartree approximation we compute the effective pion mass, thermodynamic characteristics of the system and the variance of the particle number at temperatures above the critical point of the induced Bose-Einstein condensation when the pion chemical potential reaches the value of the effective pion mass. We analyze conditions for the condensate formation in the process of thermalization of an initially non-equilibrium pion gas. The normalized variance of the particle number increases with a temperature decrease but remains finite in the critical point of the Bose-Einstein condensation. This is due to the non-perturbative account of the interaction and is in contrast to the ideal-gas case. In the kinetic regime of the condensate formation the variance is shown to stay finite also.

Cracked gas generator

Energy Technology Data Exchange (ETDEWEB)

Abthoff, J; Schuster, H D; Gabler, R

1976-11-17

A small cracked-gas generator in a vehicle driven, in particular, by an air combustion engine has been proposed for the economic production of the gases necessary for low toxicity combustion from diesel fuel. This proceeds via catalytic crack-gasification and exploitation of residual heat from exhaust gases. This patent application foresees the insertion of one of the catalysts supporting the cracked-gas reaction in a container through which the reacting mixture for cracked-gas production flows in longitudinal direction. Further, air ducts are embedded in the catalyst through which exhaust gases and fresh air flow in counter direction to the cracked gas flow in the catalyst. The air vents are connected through heat conduction to the catalyst. A cracked gas constituting H/sub 2//CO/CO/sub 2//CH/sub 4/ and H/sub 2/O can be produced from the air-fuel mixture using appropriate catalysts. By the addition of 5 to 25% of cracked gas to the volume of air drawn in by the combustion engine, a more favourable combustion can be achieved compared to that obtained under normal combustion conditions.

Slow quench dynamics of a one-dimensional Bose gas confined to an optical lattice.

Science.gov (United States)

Bernier, Jean-Sébastien; Roux, Guillaume; Kollath, Corinna

2011-05-20

We analyze the effect of a linear time variation of the interaction strength on a trapped one-dimensional Bose gas confined to an optical lattice. The evolution of different observables such as the experimentally accessible on site particle distribution are studied as a function of the ramp time by using time-dependent numerical techniques. We find that the dynamics of a trapped system typically displays two regimes: For long ramp times, the dynamics is governed by density redistribution, while at short ramp times, local dynamics dominates as the evolution is identical to that of an homogeneous system. In the homogeneous limit, we also discuss the nontrivial scaling of the energy absorbed with the ramp time.

A paradigm for modeling and computation of gas dynamics

Science.gov (United States)

Xu, Kun; Liu, Chang

2017-02-01

In the continuum flow regime, the Navier-Stokes (NS) equations are usually used for the description of gas dynamics. On the other hand, the Boltzmann equation is applied for the rarefied flow. These two equations are based on distinguishable modeling scales for flow physics. Fortunately, due to the scale separation, i.e., the hydrodynamic and kinetic ones, both the Navier-Stokes equations and the Boltzmann equation are applicable in their respective domains. However, in real science and engineering applications, they may not have such a distinctive scale separation. For example, around a hypersonic flying vehicle, the flow physics at different regions may correspond to different regimes, where the local Knudsen number can be changed significantly in several orders of magnitude. With a variation of flow physics, theoretically a continuous governing equation from the kinetic Boltzmann modeling to the hydrodynamic Navier-Stokes dynamics should be used for its efficient description. However, due to the difficulties of a direct modeling of flow physics in the scale between the kinetic and hydrodynamic ones, there is basically no reliable theory or valid governing equations to cover the whole transition regime, except resolving flow physics always down to the mean free path scale, such as the direct Boltzmann solver and the Direct Simulation Monte Carlo (DSMC) method. In fact, it is an unresolved problem about the exact scale for the validity of the NS equations, especially in the small Reynolds number cases. The computational fluid dynamics (CFD) is usually based on the numerical solution of partial differential equations (PDEs), and it targets on the recovering of the exact solution of the PDEs as mesh size and time step converging to zero. This methodology can be hardly applied to solve the multiple scale problem efficiently because there is no such a complete PDE for flow physics through a continuous variation of scales. For the non-equilibrium flow study, the direct

The Reaction Mechanism of Claisen Rearrangement Obtained by Transition State Spectroscopy and Single Direct-Dynamics Trajectory

Directory of Open Access Journals (Sweden)

Takayoshi Kobayashi

2013-02-01

Full Text Available Chemical bond breaking and formation during chemical reactions can be observed using “transition state spectroscopy”. Comparing the measurement result of the transition state spectroscopy with the simulation result of single direct-dynamics trajectory, we have elucidated the reaction dynamics of Claisen rearrangement of allyl vinyl ether. Observed the reaction of the neat sample liquid, we have estimated the time constants of transformation from straight-chain structure to aromatic-like six-membered ring structure forming the C1-C6 bond. The result clarifies that the reaction proceeds via three steps taking longer time than expected from the gas phase calculation. This finding provides new hypothesis and discussions, helping the development of the field of reaction mechanism analysis.

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.

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.

Fuel cell-gas turbine hybrid system design part II: Dynamics and control

Science.gov (United States)

McLarty, Dustin; Brouwer, Jack; Samuelsen, Scott

2014-05-01

Fuel cell gas turbine hybrid systems have achieved ultra-high efficiency and ultra-low emissions at small scales, but have yet to demonstrate effective dynamic responsiveness or base-load cost savings. Fuel cell systems and hybrid prototypes have not utilized controls to address thermal cycling during load following operation, and have thus been relegated to the less valuable base-load and peak shaving power market. Additionally, pressurized hybrid topping cycles have exhibited increased stall/surge characteristics particularly during off-design operation. This paper evaluates additional control actuators with simple control methods capable of mitigating spatial temperature variation and stall/surge risk during load following operation of hybrid fuel cell systems. The novel use of detailed, spatially resolved, physical fuel cell and turbine models in an integrated system simulation enables the development and evaluation of these additional control methods. It is shown that the hybrid system can achieve greater dynamic response over a larger operating envelope than either individual sub-system; the fuel cell or gas turbine. Results indicate that a combined feed-forward, P-I and cascade control strategy is capable of handling moderate perturbations and achieving a 2:1 (MCFC) or 4:1 (SOFC) turndown ratio while retaining >65% fuel-to-electricity efficiency, while maintaining an acceptable stack temperature profile and stall/surge margin.

Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows

Directory of Open Access Journals (Sweden)

Xia Wang

2012-12-01

Full Text Available In modeling gas-liquid two-phase flows, the concept of flow regimes has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are flow regime dependent. Current nuclear reactor safety analysis codes, such as RELAP5, classify flow regimes using flow regime maps or transition criteria that were developed for steady-state, fully-developed flows. As two-phase flows are dynamic in nature, it is important to model the flow regime transitions dynamically to more accurately predict the two-phase flows. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation of the interfacial area, fluid particle (bubble or liquid droplet disintegration, boiling and evaporation, and the destruction of the interfacial area, fluid particle coalescence and condensation. For flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations.

Demand for seasonal gas storage in northwest Europe until 2030. Simulation results with a dynamic model

International Nuclear Information System (INIS)

De Joode, J.; Oezdemir, Oe.

2010-01-01

The fact that depletion of indigenous gas production increases gas import dependency is widely known and accepted. However, there is considerable less attention for the implications of indigenous resource depletion for the provision of seasonal flexibility. The traditionally largest source of seasonal flexibility in Europe is indigenous gas production, mainly based in the Netherlands and the United Kingdom. With the depletion of indigenous sources the market increasingly needs to rely on other sources for seasonal flexibility, such as gas storage facilities. We investigate the future need for gas storage as a source for seasonal flexibility provision using a dynamic gas market model (GASTALE) in which different potential sources for seasonal flexibility - gas production, imports via pipeline, LNG imports and storage facilities - compete with each other in a market-based environment. The inclusion of seasonal flexibility properties in a gas market model allows a more complex analysis of seasonal flexibility issues than previously documented in literature. This is demonstrated in an analysis of the future demand for gas storage in northwestern Europe until 2030. Our results indicate that there is substantial need for additional gas storage facilities and thus supports current project proposals for new investment in gas storage facilities. (author)

Behavior and dynamics of bubble breakup in gas pipeline leaks and accidental subsea oil well blowouts.

Science.gov (United States)

Wang, Binbin; Socolofsky, Scott A; Lai, Chris C K; Adams, E Eric; Boufadel, Michel C

2018-06-01

Subsea oil well blowouts and pipeline leaks release oil and gas to the environment through vigorous jets. Predicting the breakup of the released fluids in oil droplets and gas bubbles is critical to predict the fate of petroleum compounds in the marine water column. To predict the gas bubble size in oil well blowouts and pipeline leaks, we observed and quantified the flow behavior and breakup process of gas for a wide range of orifice diameters and flow rates. Flow behavior at the orifice transitions from pulsing flow to continuous discharge as the jet crosses the sonic point. Breakup dynamics transition from laminar to turbulent at a critical value of the Weber number. Very strong pure gas jets and most gas/liquid co-flowing jets exhibit atomization breakup. Bubble sizes in the atomization regime scale with the jet-to-plume transition length scale and follow -3/5 power-law scaling for a mixture Weber number. Copyright © 2018 Elsevier Ltd. All rights reserved.

Plant accident dynamics of high-temperature reactors with direct gas turbine cycle

International Nuclear Information System (INIS)

Waloch, M.L.

1977-01-01

In the paper submitted, a one-dimensional accident simulation model for high-temperature reactors with direct-cycle gas turbine (single-cycle facilities) is described. The paper assesses the sudden failure of a gas duct caused by the double-ended break of one out of several parallel pipes before and behind the reactor for a non-integrated plant, leading to major loads in the reactor region, as well as the complete loss of vanes of the compressor for an integrated plant. The results of the calculations show especially high loads for the break of a hot-gas pipe immediately behind the flow restrictors of the reactor outlet, because of prolonged effects of pressure gradients in the reactor region and the maximum core differential pressure. A plant accident dynamics calculation therefore allows to find a compromise between the requirements of stable compressor operation, on the one hand, and small loads in the reactor in the course of an accident, on the other, by establishing in a co-ordinated manner the narrowing ratio of the flow restrictors. (GL) [de

Dynamic modeling of fixed-bed adsorption of flue gas using a variable mass transfer model

International Nuclear Information System (INIS)

Park, Jehun; Lee, Jae W.

2016-01-01

This study introduces a dynamic mass transfer model for the fixed-bed adsorption of a flue gas. The derivation of the variable mass transfer coefficient is based on pore diffusion theory and it is a function of effective porosity, temperature, and pressure as well as the adsorbate composition. Adsorption experiments were done at four different pressures (1.8, 5, 10 and 20 bars) and three different temperatures (30, 50 and 70 .deg. C) with zeolite 13X as the adsorbent. To explain the equilibrium adsorption capacity, the Langmuir-Freundlich isotherm model was adopted, and the parameters of the isotherm equation were fitted to the experimental data for a wide range of pressures and temperatures. Then, dynamic simulations were performed using the system equations for material and energy balance with the equilibrium adsorption isotherm data. The optimal mass transfer and heat transfer coefficients were determined after iterative calculations. As a result, the dynamic variable mass transfer model can estimate the adsorption rate for a wide range of concentrations and precisely simulate the fixed-bed adsorption process of a flue gas mixture of carbon dioxide and nitrogen.

SLOWLY ROTATING GAS-RICH GALAXIES IN MODIFIED NEWTONIAN DYNAMICS (MOND)

International Nuclear Information System (INIS)

Sánchez-Salcedo, F. J.; Martínez-García, E. E.; Hidalgo-Gámez, A. M.

2013-01-01

We have carried out a search for gas-rich dwarf galaxies that have lower rotation velocities in their outskirts than MOdified Newtonian Dynamics (MOND) predicts, so that the amplitude of their rotation curves cannot be fitted by arbitrarily increasing the mass-to-light ratio of the stellar component or by assuming additional undetected matter. With presently available data, the gas-rich galaxies UGC 4173, Holmberg II, ESO 245-G05, NGC 4861, and ESO 364-G029 deviate most from MOND predictions and, thereby, provide a sample of promising targets in testing the MOND framework. In the case of Holmberg II and NGC 4861, we find that their rotation curves are probably inconsistent with MOND, unless their inclinations and distances differ significantly from the nominal ones. The galaxy ESO 364-G029 is a promising target because its baryonic mass and rotation curve are similar to Holmberg II but presents a higher inclination. Deeper photometric and H I observations of ESO 364-G029, together with further decreasing systematic uncertainties, may provide a strong test to MOND.

The dynamics of the Frustrated Ising Lattice Gas

International Nuclear Information System (INIS)

Arenzon, J.J.; Stariolo, D.A.; Ricci-Tersenghi, F.

2000-04-01

The dynamical properties of a three dimensional model glass, the Frustrated Ising Lattice Gas (FILG) are studied by Monte Carlo simulations. We present results of compression experiments, where the chemical potential is either slowly or abruptly changed, as well as simulations at constant density. One-time quantities like density and two-times ones as correlations, responses and mean square displacements are measured, and the departure from equilibrium clearly characterized. The aging scenario, particularly in the case of the density autocorrelations, is reminiscent of spin glass phenomenology with violations of the fluctuation-dissipation theorem, typical of systems with one replica symmetry breaking. The FILG, as a valid on-lattice model of structural glasses, can be described with tools developed in spin glass theory and, being a finite dimensional model, can open the way for a systematic study of activated processes in glasses. (author)

Proceedings of the Third APEC Coal Flow Seminar

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-26

This proceedings includes papers presented at the Third APEC Coal Flow Seminar held at Terrigal, Australia in November, 1996. Keynote addresses, three sessions for discussions, and presentations by members economies are included. `Future investment requirements for coal in the APEC region,` `Barriers to investment across the APEC region coal chain,` `International commercial financier`s perspective on coal,` `The role of advanced coal technologies in greenhouse gas abatement and financing its development and uptake,` `Investment issues affecting the uptake of clean coal technology (CCT),` `Role of multilateral development banks in financing CCT to reduce greenhouse gas emissions,` and `Strategies for addressing regional coal issues` were presented as keynote addresses. In the sessions, investment issues facing coal power development, financing coal and investment, and investment strategies for CCT were discussed. 58 refs., 42 figs., 40 tabs.

Gas and heat dynamics of a micro-scaled atmospheric pressure plasma reference jet

International Nuclear Information System (INIS)

Kelly, Seán; Golda, Judith; Schulz-von der Gathen, Volker; Turner, Miles M

2015-01-01

Gas and heat dynamics of the ‘Cooperation on Science and Technology (COST) Reference Microplasma Jet’ (COST-jet), a European lead reference device for low temperature atmospheric pressure plasma application, are investigated. Of particular interest to many biomedical application scenarios, the temperature characteristics of a surface impacted by the jet are revealed. Schlieren imaging, thermocouple measurements, infrared thermal imaging and numerical modelling are employed. Temperature spatial profiles in the gas domain reveal heating primarily of the helium fraction of the gas mixture. Thermocouple and model temporal data show a bounded exponential temperature growth described by a single characteristic time parameter to reach  ∼63% or (1-1/e) fraction of the temperature increase. Peak temperatures occurred in the gas domain where the carrier jet exits the COST-jet, with values ranging from ambient temperatures to in excess of 100 °C in ‘α-mode’ operation. In a horizontal orientation of the COST-jet a curved trajectory of the helium effluent at low gas flows results from buoyant forces. Gas mixture profiles reveal significant containment of the helium concentrations for a surface placed in close proximity to the COST-jet. Surface heating of a quartz plate follows a similar bounded exponential temporal temperature growth as device heating. Spatial profiles of surface heating are found to correlate strongly to the impacting effluent where peak temperatures occur in regions of maximum surface helium concentration. (paper)

Gas and heat dynamics of a micro-scaled atmospheric pressure plasma reference jet

Science.gov (United States)

Kelly, Seán; Golda, Judith; Turner, Miles M.; Schulz-von der Gathen, Volker

2015-11-01

Gas and heat dynamics of the ‘Cooperation on Science and Technology (COST) Reference Microplasma Jet’ (COST-jet), a European lead reference device for low temperature atmospheric pressure plasma application, are investigated. Of particular interest to many biomedical application scenarios, the temperature characteristics of a surface impacted by the jet are revealed. Schlieren imaging, thermocouple measurements, infrared thermal imaging and numerical modelling are employed. Temperature spatial profiles in the gas domain reveal heating primarily of the helium fraction of the gas mixture. Thermocouple and model temporal data show a bounded exponential temperature growth described by a single characteristic time parameter to reach  ∼63% or (1-1/e) fraction of the temperature increase. Peak temperatures occurred in the gas domain where the carrier jet exits the COST-jet, with values ranging from ambient temperatures to in excess of 100 °C in ‘α-mode’ operation. In a horizontal orientation of the COST-jet a curved trajectory of the helium effluent at low gas flows results from buoyant forces. Gas mixture profiles reveal significant containment of the helium concentrations for a surface placed in close proximity to the COST-jet. Surface heating of a quartz plate follows a similar bounded exponential temporal temperature growth as device heating. Spatial profiles of surface heating are found to correlate strongly to the impacting effluent where peak temperatures occur in regions of maximum surface helium concentration.

Proceedings of the 3. International symposium environmental geochemistry in tropical countries. Book of abstracts

International Nuclear Information System (INIS)

1999-01-01

Theoretical and experimental papers are presented in these proceedings covering the following subjects: uranium mining and milling, geochemistry, land and water pollution, mineral wastes, iodine isotopes, gas chromatography, separation processes, environmental quality, qualitative and quantitative chemical analysis, rare earths, uranium isotopes, ground water, radionuclide migration, and sedimentary basins

Gas dynamic design of the pipe line compressor with 90% efficiency. Model test approval

Science.gov (United States)

Galerkin, Y.; Rekstin, A.; Soldatova, K.

2015-08-01

Gas dynamic design of the pipe line compressor 32 MW was made for PAO SMPO (Sumy, Ukraine). The technical specification requires compressor efficiency of 90%. The customer offered favorable scheme - single-stage design with console impeller and axial inlet. The authors used the standard optimization methodology of 2D impellers. The original methodology of internal scroll profiling was used to minimize efficiency losses. Radically improved 5th version of the Universal modeling method computer programs was used for precise calculation of expected performances. The customer fulfilled model tests in a 1:2 scale. Tests confirmed the calculated parameters at the design point (maximum efficiency of 90%) and in the whole range of flow rates. As far as the authors know none of compressors have achieved such efficiency. The principles and methods of gas-dynamic design are presented below. The data of the 32 MW compressor presented by the customer in their report at the 16th International Compressor conference (September 2014, Saint- Petersburg) and later transferred to the authors.

Inverse problem and uncertainty quantification: application to compressible gas dynamics

International Nuclear Information System (INIS)

Birolleau, Alexandre

2014-01-01

This thesis deals with uncertainty propagation and the resolution of inverse problems together with their respective acceleration via Polynomial Chaos. The object of this work is to present a state of the art and a numerical analysis of this stochastic spectral method, in order to understand its pros and cons when tackling the probabilistic study of hydrodynamical instabilities in Richtmyer-Meshkov shock tube experiments. The first chapter is introductory and allows understanding the stakes of being able to accurately take into account uncertainties in compressible gas dynamics simulations. The second chapter is both an illustrative state of the art on generalized Polynomial Chaos and a full numerical analysis of the method keeping in mind the final application on hydrodynamical problems developing shocks and discontinuous solutions. In this chapter, we introduce a new method, naming iterative generalized Polynomial Chaos, which ensures a gain with respect to generalized Polynomial Chaos, especially with non smooth solutions. Chapter three is closely related to an accepted publication in Communication in Computational Physics. It deals with stochastic inverse problems and introduces bayesian inference. It also emphasizes the possibility of accelerating the bayesian inference thanks to iterative generalized Polynomial Chaos described in the previous chapter. Theoretical convergence is established and illustrated on several test-cases. The last chapter consists in the application of the above materials to a complex and ambitious compressible gas dynamics problem (Richtmyer-Meshkov shock tube configuration) together with a deepened study of the physico-numerical phenomenon at stake. Finally, in the appendix, we also present some interesting research paths we quickly tackled during this thesis. (author) [fr

Solvation of ions in the gas-phase: a molecular dynamics simulation

Science.gov (United States)

Cabarcos, Orlando M.; Lisy, James M.

1996-07-01

Molecular dynamics simulations have been performed on the collision between a cesium ion and a cluster of twenty methanol molecules. This process, generating a solvated ion, was studied over a range (1 to 25 eV) of eight collision energies. Preliminary analysis of this gas phase solvation has included the distribution of final ion cluster sizes, fragmentation patterns, solvation timescales and energetics. Two distinct patterns have emerged: a ballistic penetration of the neutral cluster at the higher collision energies and an evaporative evolution of the cluster ion at lower collision energies.

Molecular dynamics study of the influence of wall-gas interactions on heat flow in nanochannels

NARCIS (Netherlands)

Markvoort, Albert. J.; Hilbers, P.A.J.; Nedea, S.V.

2005-01-01

Especially at the nanometer scale interfaces play an important role. The effect of the wettability on the solid-liquid interface has already been studied with molecular dynamics. In this paper we study the dependence of wetting on the solid-gas interface for different density gases and investigate

World Gas Conference 1997. Working committee H. Liquefied gases

International Nuclear Information System (INIS)

1997-01-01

This volume of the proceedings contains the report of the International Gas Union's Working Committee H, Liquefied gases, and oral and poster papers presented at the conference. The committee report and each paper have been abstracted separately. (LN)

Proceedings of the ENCIT 2004: 10. Brazilian congress of thermal engineering and sciences. Abstracts

International Nuclear Information System (INIS)

2004-01-01

Theoretical and experimental papers are presented in this proceedings covering the following subjects: petroleum, industry, fractions and distillates, gas turbines and power plants, reservoir engineering, oil field and wells, offshore drilling, electric power generation, catalysis, aerodynamics, energy consumption and conservation, heat transfer and engines, refrigeration, porous materials and numerical analysis

Supersymmetry: proceedings

International Nuclear Information System (INIS)

Brennan, E.C.

1985-07-01

Some lectures in these proceedings examine the theoretical basis for supersymmetry, recent developments in theories with compact dimensions, and experimental searches for supersymmetric signatures. Technologies are explored for obtaining very high energy electron-positron colliding beams. Separate abstracts were prepared for 35 papers in these conference proceedings

Short- and Long-Term Dynamics of Gas Hydrate at GC600: A Gulf of Mexico Hydrocarbon Seep

Science.gov (United States)

MacDonald, I. R.; Johansen, C.; Silva, M.; Daneshgar, S.; Garcia-Pineda, O. G.; Shedd, W. W.

2014-12-01

The GC600 hydrocarbon seep is located at 1200 m in the northern Gulf of Mexico (GOM). Satellite data show it to be one of the most prolific sources of natural oil slicks in the entire GOM. We mapped its seafloor oil and gas vents with 3-D seismic, swath-bathymetry acoustics and submersible observations, documenting gas hydrate deposits, brine pools, benthic fauna, and authigenic carbonates. Geophysical profiles show subbottom locations of salt bodies and migration conduits. We deployed time-lapse imaging systems focused on individual vents to quantify release rates. Oil and gas flow upward along the flanks of an allochthonous salt body from source rocks at 10,000 m and migrate to the seafloor from faults emanating from the salt. Venting to the water column and surface consists of oily bubbles and occurs in two fields separated by ~1 km. The NW vent field (Megaplume) appears to be a more recent expression and hosts about three highly active vents; while the SE vent field (Birthday Candles) hosts more than 10 vents that are generally slower. We measured discharge rates of 2.6 cm3 s-1 and Megaplume and 0.09 cm3 s-1 at Birthday Candles. Although surface deposits of gas hydrate were evident at both vent fields, the Birthday Candles area featured dozens of conical mounds formed by gas hydrate that were dark brown due to large amounts of liquid oil perfused throughout the deposits. Large brine pools indicated gas hydrate formation at the seafloor. Venting occurred in horizontal fissures on the mounds, in which oil and hydrate combined to form short-lived chimneys and balloon-like structures. Ice worms (Hesiocaeca methanicola) were extremely abundant in burrows extending from the sediment into the gas hydrate. Proceeding farther to the SE, venting is reduced and absent, but surface carbonate deposits suggest relict gas hydrate mounds. We propose that the NW to SE trend at GC600 encompasses the progressive development of a biogeochemical filter that sequesters and

Gas dynamic improvement of the axial compressor design for reduction of the flow non-uniformity level

Science.gov (United States)

Matveev, V. N.; Baturin, O. V.; Kolmakova, D. A.; Popov, G. M.

2017-01-01

Circumferential nonuniformity of gas flow is one of the main problems in the gas turbine engine. Usually, the flow circumferential nonuniformity appears near the annular frame located in the flow passage of the engine. The presence of circumferential nonuniformity leads to the increased dynamic stresses in the blade rows and the blade damage. The goal of this research was to find the ways of the flow non-uniformity reduction, which would not require a fundamental changing of the engine design. A new method for reducing the circumferential nonuniformity of the gas flow was proposed that allows the prediction of the pressure peak values of the rotor blades without computationally expensive CFD calculations.

Shock dynamics of weak imploding cylindrical and spherical shock waves with non-ideal gas effects

International Nuclear Information System (INIS)

Anand, R K

2013-01-01

The author (Anand 2012 Astrophys. Space Sci. 342 377–88) recently obtained jump relations across a shock front in non-ideal gas flow taking into consideration the equation of state for a non-ideal gas as given by Landau and Lifshitz. In this paper an analytical solution for one-dimensional adiabatic flow behind weak converging shock waves propagating in a non-ideal gas is obtained by using Whitham's (1974 Linear and Nonlinear Waves (New York: Wiley)) geometrical shock dynamics approach. The effects of an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and (iii) the adiabatic index of the gas, on the shock velocity, pressure, density, particle velocity, adiabatic compressibility and the change in entropy across the shock front, are analyzed. The results provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the imploding shock front. (paper)

The sensitivity and dynamic response of field ionization gas sensor based on ZnO nanorods

International Nuclear Information System (INIS)

Min Jiahua; Liang Xiaoyan; Wang Bin; Wang Linjun; Zhao Yue; Shi Weimin; Xia Yiben

2011-01-01

Field ionization gas sensors based on ZnO nanorods (50–300 nm in diameter, and 3–8 μm in length) with and without a buffer layer were fabricated, and the influence of the orientation of nano-ZnO on the ionization response of devices was discussed, including the sensitivity and dynamic response of the ZnO nanorods with preferential orientation. The results indicated that ZnO nanorods as sensor anode could dramatically decrease the breakdown voltage. The XRD and SEM images illustrated that nano-ZnO with a ZnO buffer layer displayed high c-axis orientation, which helps to significantly reduce the breakdown voltage. Device A based on ZnO nanorods with a ZnO buffer layer could distinguish toluene and acetone. The dynamic responses of device A to the NO x compounds presented the sensitivity of 0.045 ± 0.007 ppm/pA and the response speed within 17–40 s, and indicated a linear relationship between NO x concentration and current response at low NO x concentrations. In addition, the dynamic responses to benzene, isopropyl alcohol, ethanol, and methanol reveals that the device has higher sensitivity to gas with larger static polarizability and lower ionization energy.

Supersymmetry: proceedings

Energy Technology Data Exchange (ETDEWEB)

Brennan, E.C. (ed.)

1985-07-01

Some lectures in these proceedings examine the theoretical basis for supersymmetry, recent developments in theories with compact dimensions, and experimental searches for supersymmetric signatures. Technologies are explored for obtaining very high energy electron-positron colliding beams. Separate abstracts were prepared for 35 papers in these conference proceedings. (LEW)

Fission gas behaviour in water reactor fuels

International Nuclear Information System (INIS)

2002-01-01

During irradiation, nuclear fuel changes volume, primarily through swelling. This swelling is caused by the fission products and in particular by the volatile ones such as krypton and xenon, called fission gas. Fission gas behaviour needs to be reliably predicted in order to make better use of nuclear fuel, a factor which can help to achieve the economic competitiveness required by today's markets. These proceedings communicate the results of an international seminar which reviewed recent progress in the field of fission gas behaviour in light water reactor fuel and sought to improve the models used in computer codes predicting fission gas release. State-of-the-art knowledge is presented for both uranium-oxide and mixed-oxide fuels loaded in water reactors. (author)

Proceedings of the ENCIT 2008: 12. Brazilian congress of thermal sciences and engineering

International Nuclear Information System (INIS)

Koury, Ricardo Nicolau Nassar; Barbosa, Marcos Pinotti

2008-01-01

Theoretical and experimental papers are presented in this proceedings covering the following subjects: petroleum, industry, fractions and distillates, gas turbines and power plants, reservoir engineering, oil field and wells, offshore operation, electric power generation, aerospace engineering, heat and mass transfer, refrigeration, ventilation and building simulation, nuclear engineering, instrumentation and metrology, fluid mechanics, rheology, environment and numerical analysis

Determination of dynamic variations in the optical properties of graphene oxide in response to gas exposure based on thin-film interference.

Science.gov (United States)

Tabassum, Shawana; Dong, Liang; Kumar, Ratnesh

2018-03-05

We present an effective yet simple approach to study the dynamic variations in optical properties (such as the refractive index (RI)) of graphene oxide (GO) when exposed to gases in the visible spectral region, using the thin-film interference method. The dynamic variations in the complex refractive index of GO in response to exposure to a gas is an important factor affecting the performance of GO-based gas sensors. In contrast to the conventional ellipsometry, this method alleviates the need of selecting a dispersion model from among a list of model choices, which is limiting if an applicable model is not known a priori. In addition, the method used is computationally simpler, and does not need to employ any functional approximations. Further advantage over ellipsometry is that no bulky optics is required, and as a result it can be easily integrated into the sensing system, thereby allowing the reliable, simple, and dynamic evaluation of the optical performance of any GO-based gas sensor. In addition, the derived values of the dynamically changing RI values of the GO layer obtained from the method we have employed are corroborated by comparing with the values obtained from ellipsometry.

Sensor 2001 - 10th International conference. Vol. 1 and 2. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The proceedings of the 10th international conference on sensors 2001 consists of two volumes. Volume I contains works under the following headers: Automotive sensors, position and acceleration, biosensors, electronic nose and tongue, optical sensors, technology and materials, signal processing, marketing, simulation, smart home, wireless sensing. Main topics of volume II are: pressure and force, flow, gas sensors, the microsystems innovation forum, and all works presented in the poster sessions. (uke)

Status and prospects for gas cooled reactor fuels. Proceedings of two IAEA meetings held in June 2004 and June 2005

International Nuclear Information System (INIS)

2009-04-01

Recently, efforts to develop high temperature gas cooled reactors with an aim to building futuristic nuclear energy systems with advanced nuclear fuel cycles in the context of the Generation IV International Forum have increased significantly. In addition, several development projects are ongoing, focusing on the burning of weapons grade plutonium, including civil plutonium and other transuranic elements using the 'deep-burn concept', or 'inert matrix fuels', especially in the form of coated particles in gas cooled reactor systems. There is also considerable global interest in developing 'nuclear hydrogen' energy systems using high temperature gas cooled reactors. Apart from these developments, the value of preserving the large technology base developed in Germany, the United Kingdom and the United States of America, as well as information developed in other countries, has also been a subject of interest to the IAEA. At the second annual meeting of the 'technical working group on nuclear fuel cycles options and spent fuel management' (TWG-NFCO), held in Vienna from 28-30 May 2003, it was recommended to hold a technical meeting on Current Status and Future Prospects of Gas Cooled Reactor Fuels. The meeting should cover the technological progress that has been made in the last three years and plan future fabrication and qualification facilities for GCR/HTR fuel. TWG-NFCO considered it timely that this progress should be presented and discussed in the interested community. Recognizing the numerous activities being pursued in many Member States, the IAEA convened the technical meeting on this topic in June 2004 in Vienna. Consequently, an update meeting was held in June 2005, which was hosted by the Kharkov Institute of Physics and Technology of Ukraine to review and integrate the latest developments. This publication combines the results of the technical meeting of June 2004 and the meeting of June 2005. The proceedings presented here contain 25 in depth papers on the

Interactions of Delta Shock Waves for Zero-Pressure Gas Dynamics with Energy Conservation Law

OpenAIRE

Wei Cai; Yanyan Zhang

2016-01-01

We study the interactions of delta shock waves and vacuum states for the system of conservation laws of mass, momentum, and energy in zero-pressure gas dynamics. The Riemann problems with initial data of three piecewise constant states are solved case by case, and four different configurations of Riemann solutions are constructed. Furthermore, the numerical simulations completely coinciding with theoretical analysis are shown.

Reactive molecular dynamic simulations on the gas separation performance of porous graphene membrane.

Science.gov (United States)

Esfandiarpoor, Somaye; Fazli, Mostafa; Ganji, Masoud Darvish

2017-11-29

The separation of gases molecules with similar diameter and shape is an important area of research. For example, the major challenge to set up sweeping carbon dioxide capture and storage (CCS) in power plants is the energy requisite to separate the CO 2 from flue gas. Porous graphene has been proposed as superior material for highly selective membranes for gas separation. Here we design some models of porous graphene with different sizes and shape as well as employ double layers porous graphene for efficient CO 2 /H 2 separation. The selectivity and permeability of gas molecules through various nanopores were investigated by using the reactive molecular dynamics simulation which considers the bond forming/breaking mechanism for all atoms. Furthermore, it uses a geometry-dependent charge calculation scheme that accounts appropriately for polarization effect which can play an important role in interacting systems. It was found that H-modified porous graphene membrane with pore diameter (short side) of about 3.75 Å has excellent selectivity for CO 2 /H 2 separation. The mechanism of gas penetration through the sub-nanometer pore was presented for the first time. The accuracy of MD simulation results validated by valuable DFT method. The present findings show that reactive MD simulation can propose an economical means of separating gases mixture.

Delta-nucleus dynamics: proceedings of symposium

International Nuclear Information System (INIS)

Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P.

1983-10-01

The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta Δ(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe Δ-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented

Delta-nucleus dynamics: proceedings of symposium

Energy Technology Data Exchange (ETDEWEB)

Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P. (eds.)

1983-10-01

The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

Gas Dynamics in Planetary Nebulae: From Macro-structures to FLIERs

Science.gov (United States)

Perinotto, Mario

2000-10-01

Purpose of this paper is to clarify how Planetary Nebulae (PNe) are very interesting laboratories to study cosmic gas dynamics. I first recall the history of PNe which are generated from low and intermediate mass stars through successive mass loss processes starting in the Reg Giant phase of evolution and continuing also after the termination of the pulsed AGB phase, where most of the nebular mass is believed to be ejected. The correponding stellar winds are the ingredients of the nebula. Their initial properties and subsequent mutual interactions, under the action of the evolving stellar radiation field, are responsible for the properties of the nebula. The observed structures of PNe are considered in detail. Larger scale macroscopic structures (MACS) are examined separately from quite smaller scale microscopic structures (MICS). The formation of MACS, at least in cases of round to moderately elliptical PNe, is shown to be reasonably well understood in terms of existing hydrodynamical models. Considering the kinematical behaviour, MICS can be separated into FLIERs (Fast Low Ionization Emitting Regions) and SLOWERs (slowly moving). Attention is focussed on FLIERs and on the proposed mechanisms to interpret them. Recent observations with the Hubble Space Telescope have provided us with a wealth of detailed (subarcsec) information on the nebular structures. The inner structure of FLIERs is here illustrated to consist of substructures of various shapes with an high degree of individually from object to object, also within the same PN. These new data call for deeper thoretical efforts to solve the problems of cosmic gas dynamics, posed by their observed properties. An ample account is given of the most relevant original works, in an effort to allow the non specialist reader to quickly become acquainted with the status of art in the various aspects of the subject.

Dynamical Behavior of Multi-Robot Systems Using Lattice Gas Automata

Energy Technology Data Exchange (ETDEWEB)

Cameron, S.M.; Robinett, R.; Stantz, K.M.; Trahan, M.W.; Wagner, J.S.

1999-03-11

Recent attention has been given to the deployment of an adaptable sensor array realized by multi-robotic systems. Our group has been studying the collective behavior of autonomous, multi-agent systems and their applications in the area of remote-sensing and emerging threats. To accomplish such tasks, an interdisciplinary research effort at Sandia National Laboratories are conducting tests in the fields of sensor technology, robotics, and multi-robotic and multi-agents architectures. Our goal is to coordinate a constellation of point sensors that optimizes spatial coverage and multivariate signal analysis using unmanned robotic vehicles (e.g., RATLERs, Robotic All-ten-sin Lunar Exploration Rover-class vehicles). Overall design methodology is to evolve complex collective behaviors realized through simple interaction (kinetic) physics and artificial intelligence to enable real-time operational responses to emerging threats. This paper focuses on our recent work understanding the dynamics of many-body systems using the physics-based hydrodynamic model of lattice gas automata. Three design features are investigated. One, for single-speed robots, a hexagonal nearest-neighbor interaction topology is necessary to preserve standard hydrodynamic flow. Two, adaptability, defined by the swarm's deformation rate, can be controlled through the hydrodynamic viscosity term, which, in turn, is defined by the local robotic interaction rules. Three, due to the inherent non-linearity of the dynamical equations describing large ensembles, development of stability criteria ensuring convergence to equilibrium states is developed by scaling information flow rates relative to a swarm's hydrodynamic flow rate. An initial test case simulates a swarm of twenty-five robots that maneuvers past an obstacle while following a moving target. A genetic algorithm optimizes applied nearest-neighbor forces in each of five spatial regions distributed over the simulation domain. Armed with

Western tight gas sands advanced logging workshop proceedings

Energy Technology Data Exchange (ETDEWEB)

Jennings, J B; Carroll, Jr, H B [eds.

1982-04-01

An advanced logging research program is one major aspect of the Western Tight Sands Program. Purpose of this workshop is to help BETC define critical logging needs for tight gas sands and to allow free interchange of ideas on all aspects of the current logging research program. Sixteen papers and abstracts are included together with discussions. Separate abstracts have been prepared for the 12 papers. (DLC)

The method of the gas-dynamic centrifugal compressor stage characteristics recalculation for variable rotor rotational speeds and the rotation angle of inlet guide vanes blades if the kinematic and dynamic similitude conditions are not met

Science.gov (United States)

Vanyashov, A. D.; Karabanova, V. V.

2017-08-01

A mathematical description of the method for obtaining gas-dynamic characteristics of a centrifugal compressor stage is proposed, taking into account the control action by varying the rotor speed and the angle of rotation of the guide vanes relative to the "basic" characteristic, if the kinematic and dynamic similitude conditions are not met. The formulas of the correction terms for the non-dimensional coefficients of specific work, consumption and efficiency are obtained. A comparative analysis of the calculated gas-dynamic characteristics of a high-pressure centrifugal stage with experimental data is performed.

Dynamic simulation of a furnace of steam reforming of natural gas

International Nuclear Information System (INIS)

Acuna, A; Fuentes, C; Smith, C A

1999-01-01

Steam reforming of natural gas is a very important industrial process in refineries and ammonia and methanol plants. Hydrogen is produced by reforming methane with steam. This hydrogen is essential in the hydro-treating process in the refineries thus, it is important to supervise and control the performance of the hydrogen plant. Mathematical models of refineries and chemical plants are used to simulate the behavior of the process units. However, the models especially of reactors like reformers are not very reliable. This paper presents a dynamic model of a furnace-reactor. The simulation results are validated with industrial data

Technology of steam generators for gas-cooled reactors. Proceedings of a specialists' meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

1988-07-01

The activity of the IAEA in the field of the technology of gas-cooled reactors was formalized by formation of an International Working Group on Gas-Cooled Reactors (IWGCR). The gas cooled reactor program considered by the IWGCR includes carbon-dioxide-cooled thermal reactors, helium cooled thermal high temperature reactors for power generation and for process heat applications and gas-cooled fast breeder reactors. This report covers the papers dealing with operating experience, steam generators for next generation of gas-cooled reactors, material development and corrosion problems, and thermohydraulics.

Technology of steam generators for gas-cooled reactors. Proceedings of a specialists' meeting

International Nuclear Information System (INIS)

1988-01-01

The activity of the IAEA in the field of the technology of gas-cooled reactors was formalized by formation of an International Working Group on Gas-Cooled Reactors (IWGCR). The gas cooled reactor program considered by the IWGCR includes carbon-dioxide-cooled thermal reactors, helium cooled thermal high temperature reactors for power generation and for process heat applications and gas-cooled fast breeder reactors. This report covers the papers dealing with operating experience, steam generators for next generation of gas-cooled reactors, material development and corrosion problems, and thermohydraulics

Modelling the Dynamic Interaction Power System Lamp - Application to High Pressure Mercury Gas Discharge Lamps

Directory of Open Access Journals (Sweden)

ZIANE, M.

2007-11-01

Full Text Available The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp, this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on "channel" approximation of the high pressure mercury (HPM gas-discharge lamp, is developed to determine the physical and electric magnitudes, which characterize the dynamic behavior of the couple "lamp-electrical power system". The evolution of the lamp properties when principal parameters of the discharge (pressure of mercury, voltage supply, frequency are varying were studied and analyzed. We show the concordance between simulation, calculations and measurements for electric, energetic or irradiative characteristics. The model reproduces well the evolution of properties of the supply when principal parameters of the discharge vary.

Interactions of Delta Shock Waves for Zero-Pressure Gas Dynamics with Energy Conservation Law

Directory of Open Access Journals (Sweden)

Wei Cai

2016-01-01

Full Text Available We study the interactions of delta shock waves and vacuum states for the system of conservation laws of mass, momentum, and energy in zero-pressure gas dynamics. The Riemann problems with initial data of three piecewise constant states are solved case by case, and four different configurations of Riemann solutions are constructed. Furthermore, the numerical simulations completely coinciding with theoretical analysis are shown.

Reducing pollution at five critical points of shale gas production: Strategies and institutional responses

International Nuclear Information System (INIS)

Centner, Terence J.

2016-01-01

While the public and governments debate the advisability of engaging in shale gas production, the United States has proceeded to develop its resources with an accompanying remarkable increase in natural gas production. The development of shale gas has not been without problems, and some countries have decided that shale gas production should not proceed until more is known about the accompanying health issues and environmental damages. From experiences in the United States, careful consideration of five critical points relating to shale gas production can form the basis for developing strategies for reducing discharges of pollutants: (1) casing and cementing, (2) handling wastewater, (3) venting and flaring, (4) equipment with air emissions, and (5) seismic events. For each strategy, institutional responses to markedly reduce the risks of harm to people and the environment are identified. These responses offer state and local governments ideas for enabling shale gas resources to be developed without sacrificing public health and environmental quality. - Highlights: •Shale gas development involves releases of unnecessary pollutants. •Major sources of unnecessary pollutants can be identified. •For major pollutant sources, strategies can be developed to reduce releases of contaminants. •Alternative strategies can offer firms and governments ways to reduce pollutant releases.

Non-invasive and non-intrusive gas flow measurement based on the dynamic thermal characteristics of a pipeline

Science.gov (United States)

Fan, Zichuan; Cai, Maolin; Xu, Weiqing

2012-10-01

This paper proposes a non-intrusive and non-invasive method for measuring the gas flow rate in pneumatic industry. A heater unit is fixed on the partial circumference of the external wall of a pipeline and emits specific thermal pulses in a predetermined mode. Two sensors attached to the external wall detect the upstream temperature, and the gas flow can be measured according to the relationship between the flow rate and the dynamic thermal characteristics of the pipeline. To determine the preferable relationship, the temperature field model of the measurement system is built. Then, based on the measurement modes and the corresponding simulations, the objective functions for the gas flow specified on different dynamic thermal characteristics are established. Additionally, the minimum measurement time of the method, named reference time scale, is proposed. Further, robustness tests of the measurement method are derived by considering the influences of multiple factors on the objective functions. The experiments confirm that this method does not need to open the pipeline and disturb the flow regime in order to obtain the data; this method also avoids the typical time-consuming and complex operations, resists ambient temperature disturbance and achieves approximately acceptable results.

Non-invasive and non-intrusive gas flow measurement based on the dynamic thermal characteristics of a pipeline

International Nuclear Information System (INIS)

Fan, Zichuan; Cai, Maolin; Xu, Weiqing

2012-01-01

This paper proposes a non-intrusive and non-invasive method for measuring the gas flow rate in pneumatic industry. A heater unit is fixed on the partial circumference of the external wall of a pipeline and emits specific thermal pulses in a predetermined mode. Two sensors attached to the external wall detect the upstream temperature, and the gas flow can be measured according to the relationship between the flow rate and the dynamic thermal characteristics of the pipeline. To determine the preferable relationship, the temperature field model of the measurement system is built. Then, based on the measurement modes and the corresponding simulations, the objective functions for the gas flow specified on different dynamic thermal characteristics are established. Additionally, the minimum measurement time of the method, named reference time scale, is proposed. Further, robustness tests of the measurement method are derived by considering the influences of multiple factors on the objective functions. The experiments confirm that this method does not need to open the pipeline and disturb the flow regime in order to obtain the data; this method also avoids the typical time-consuming and complex operations, resists ambient temperature disturbance and achieves approximately acceptable results. (paper)

Quantitative Analysis of Bioactive Compounds from Aromatic Plants by Means of Dynamic Headspace Extraction and Multiple Headspace Extraction-Gas Chromatography-Mass Spectrometry

NARCIS (Netherlands)

Omar, Jone; Olivares, Maitane; Alonso, Ibone; Vallejo, Asier; Aizpurua-Olaizola, Oier; Etxebarria, Nestor

2016-01-01

Seven monoterpenes in 4 aromatic plants (sage, cardamom, lavender, and rosemary) were quantified in liquid extracts and directly in solid samples by means of dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS) and multiple headspace extraction-gas chromatography-mass spectrometry

CFD model of a spinning pipe gas lens

CSIR Research Space (South Africa)

Snedden, Glen C

2006-07-01

Full Text Available Slides on: Spinning Pipe Gas Lens; Focal Length; Refractive Index; Gas Dynamics; Guess at the gas dynamics; Density Profile; Flow Profile; Rosby Waves; Rayleigh–Taylor Instabilities...

Topological phase transition in the quench dynamics of a one-dimensional Fermi gas with spin–orbit coupling

International Nuclear Information System (INIS)

Wang, Pei; Yi, Wei; Xianlong, Gao

2015-01-01

We study the quench dynamics of a one-dimensional ultracold Fermi gas with synthetic spin-orbit coupling. At equilibrium, the ground state of the system can undergo a topological phase transition and become a topological superfluid with Majorana edge states. As the interaction is quenched near the topological phase boundary, we identify an interesting dynamical phase transition of the quenched state in the long-time limit, characterized by an abrupt change of the pairing gap at a critical quenched interaction strength. We further demonstrate the topological nature of this dynamical phase transition from edge-state analysis of the quenched states. Our findings provide interesting clues for the understanding of topological phase transitions in dynamical processes, and can be useful for the dynamical detection of Majorana edge states in corresponding systems. (paper)

Topological phase transition in the quench dynamics of a one-dimensional Fermi gas with spin-orbit coupling

Science.gov (United States)

Wang, Pei; Yi, Wei; Xianlong, Gao

2015-01-01

We study the quench dynamics of a one-dimensional ultracold Fermi gas with synthetic spin-orbit coupling. At equilibrium, the ground state of the system can undergo a topological phase transition and become a topological superfluid with Majorana edge states. As the interaction is quenched near the topological phase boundary, we identify an interesting dynamical phase transition of the quenched state in the long-time limit, characterized by an abrupt change of the pairing gap at a critical quenched interaction strength. We further demonstrate the topological nature of this dynamical phase transition from edge-state analysis of the quenched states. Our findings provide interesting clues for the understanding of topological phase transitions in dynamical processes, and can be useful for the dynamical detection of Majorana edge states in corresponding systems.

Materials for advanced power engineering 2010. Proceedings

International Nuclear Information System (INIS)

Lecomte-Beckers, Jacqueline; Contrepois, Quentin; Beck, Tilmann; Kuhn, Bernd

2010-01-01

The 9th Liege Conference on ''Materials for Advanced Power Engineering'' presents the results of the materials related COST Actions 536 ''Alloy Development for Critical Components of Environmentally Friendly Power Plants'' and 538 ''High Temperature Plant Lifetime Extension''. In addition, the broad field of current materials research perspectives for high efficiency, low- and zero- emission power plants and new energy technologies for the next decades are reported. The Conference proceedings are structured as follows: 1. Materials for advanced steam power plants; 2. Gas turbine materials; 3. Materials for nuclear fission and fusion; 4. Solid oxide fuel cells; 5. Corrosion, thermomechanical fatigue and modelling; 6. Zero emission power plants.

Materials for advanced power engineering 2010. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Lecomte-Beckers, Jacqueline; Contrepois, Quentin; Beck, Tilmann; Kuhn, Bernd [eds.

2010-07-01

The 9th Liege Conference on ''Materials for Advanced Power Engineering'' presents the results of the materials related COST Actions 536 ''Alloy Development for Critical Components of Environmentally Friendly Power Plants'' and 538 ''High Temperature Plant Lifetime Extension''. In addition, the broad field of current materials research perspectives for high efficiency, low- and zero- emission power plants and new energy technologies for the next decades are reported. The Conference proceedings are structured as follows: 1. Materials for advanced steam power plants; 2. Gas turbine materials; 3. Materials for nuclear fission and fusion; 4. Solid oxide fuel cells; 5. Corrosion, thermomechanical fatigue and modelling; 6. Zero emission power plants.

Statistical mechanical model of gas adsorption in porous crystals with dynamic moieties.

Science.gov (United States)

Simon, Cory M; Braun, Efrem; Carraro, Carlo; Smit, Berend

2017-01-17

Some nanoporous, crystalline materials possess dynamic constituents, for example, rotatable moieties. These moieties can undergo a conformation change in response to the adsorption of guest molecules, which qualitatively impacts adsorption behavior. We pose and solve a statistical mechanical model of gas adsorption in a porous crystal whose cages share a common ligand that can adopt two distinct rotational conformations. Guest molecules incentivize the ligands to adopt a different rotational configuration than maintained in the empty host. Our model captures inflections, steps, and hysteresis that can arise in the adsorption isotherm as a signature of the rotating ligands. The insights disclosed by our simple model contribute a more intimate understanding of the response and consequence of rotating ligands integrated into porous materials to harness them for gas storage and separations, chemical sensing, drug delivery, catalysis, and nanoscale devices. Particularly, our model reveals design strategies to exploit these moving constituents and engineer improved adsorbents with intrinsic thermal management for pressure-swing adsorption processes.

Gas dynamic laser having shutter doors

International Nuclear Information System (INIS)

Olinger, J.B. Jr.; Wahl, R.L.

1975-01-01

A gas dynamic laser is shown wherein gases containing constituents necessary to obtain a lasing action are passed through a nozzle array and directed into a lasing cavity and through a diffuser to an exit. An opening is located on each side of said lasing cavity with a shutter box outside of said cavity having a shutter door for opening or closing said opening. A mirror box is located behind each shutter box and contains a mirror. These mirrors are aligned with the openings in the lasing cavity with each door positioned between an opening and a mirror. Another outlet opening is positioned downstream of the first opening which provides an outlet opening for a laser beam. A shutter box is located around this opening and also houses a shutter door for opening and closing said opening. The mirror box which extends behind this shutter box includes opening means for permitting the output beam to pass through an aerodynamic window to atmosphere. Actuating means are provided for rapidly opening and closing said shutter doors. Bearing means including recirculating balls are located on the top and bottom of each shutter door to ride in tracks at an angle to the sealing surface on the laser device. Vacuum means are provided to reduce the pressure in the shutter box and mirror box independently of the pressure in the lasing cavity

Steady-state and dynamic analysis of a jet engine, gas lubricated shaft seal

Science.gov (United States)

Shapiro, W.; Colsher, R.

1974-01-01

Dynamic response of a gas-lubricated, jet-engine main shaft seal was analytically established as a function of collar misalignment and secondary seal friction. Response was obtained by a forward integration-in-time (time-transient) scheme, which traces a time history of seal motions in all its degrees of freedom. Results were summarized in the form of a seal tracking map which indicated regions of acceptable collar misalignments and secondary seal friction. Methodology, results and interpretations are comprehensively described.

Dynamics of gas-phase transient species studied by dissociative photodetachment of molecular anions

OpenAIRE

Lu, Zhou

2007-01-01

Gas-phase transient species, such as the CH₃CO₂ and HOCO free radicals, play important roles in combustion and environment chemistry. In this thesis work, the dynamics of these two radicals were studied by dissociative photodetachment (DPD) of the negative ions, CH₃CO₂-С and HOCO⁻, respectively. The experiments were carried out with a fast-ion-beam photoelectron-photofragment coincidence (PPC) spectrometer. Mass-selected molecular anions in a fast ion beam were intercepted by a linearly polar...

Effects of Gas Rarefaction on Dynamic Characteristics of Micro Spiral-Grooved Thrust Bearing

OpenAIRE

Liu, Ren; Wang, Xiao-Li; Zhang, Xiao-Qing

2012-01-01

The effects of gas-rarefaction on dynamic characteristics of micro spiral-grooved-thrust-bearing are studied. The Reynolds equation is modified by the first order slip model, and the corresponding perturbation equations are then obtained on the basis of the linear small perturbation method. In the converted spiral-curve-coordinates system, the finite-volume-method (FVM) is employed to discrete the surface domain of micro bearing. The results show, compared with the continuum-flow model, that ...

Fundamental study on repairing technique for cracked or damaged parts of structures by cold gas dynamic spray technique

International Nuclear Information System (INIS)

Ogawa, Kazuhiro; Amao, Satoshi; Ichikawa, Yuji; Shoji, Tetsuo

2008-01-01

This study proposes an innovative technique for repairing of cracked or damaged parts of structures, such as nuclear or thermal power plants, by means of cold gas dynamic spray (CS) technique. In the case of generation of cracks etc. in the structure, the cracks can be repaired by welding. However, the welding spends considerable time on repair, and also needs special skills. The CS technique is known as a new technique not only for coatings but also for thick depositions. It has many advantages, i.e. dense deposition, high deposition rate and low oxidation. Therefore, it has a possibility to apply the CS technique instead of welding to repair the cracks etc. In this study, the cold gas dynamic spray technique as a new repairing technique for some structures is introduced. (author)

Proceedings of emerging technologies for hazardous waste management

International Nuclear Information System (INIS)

Tedder, D.W.

1992-01-01

This book contains proceedings of emerging technologies for hazardous waste management. Topics covered include: Low-temperature oxidation of organic chemical wastes; Advanced waste minimization strategies; Treatment of manufactured gas plant (MGP) and similar wastes; Bioremediation of soils and sediments; Advances in radioactive waste treatment; Computer aides approaches to hazardous waste management; Advances in soil remediation; Low-temperature oxidation of organic chemical waste; Boremediation: Micro, meso, and macro-scale processes; In situ remediation techniques; Treatment of hazardous organics with radiation or solar energy; Technologies for management of municipal waste combustion residues; Environmental restoration and waste management; and Advanced separation and stabilization technologies

Experimental Combustion Dynamics Behavior of a Multi-Element Lean Direct Injection (LDI) Gas Turbine Combustor

Science.gov (United States)

Acosta, Waldo A.; Chang, Clarence T.

2016-01-01

An experimental investigation of the combustion dynamic characteristics of a research multi-element lean direct injection (LDI) combustor under simulated gas turbine conditions was conducted. The objective was to gain a better understanding of the physical phenomena inside a pressurized flametube combustion chamber under acoustically isolated conditions. A nine-point swirl venturi lean direct injection (SV-LDI) geometry was evaluated at inlet pressures up to 2,413 kPa and non-vitiated air temperatures up to 867 K. The equivalence ratio was varied to obtain adiabatic flame temperatures between 1388 K and 1905 K. Dynamic pressure measurements were taken upstream of the SV-LDI, in the combustion zone and downstream of the exit nozzle. The measurements showed that combustion dynamics were fairly small when the fuel was distributed uniformly and mostly due to fluid dynamics effects. Dynamic pressure fluctuations larger than 40 kPa at low frequencies were measured at 653 K inlet temperature and 1117 kPa inlet pressure when fuel was shifted and the pilot fuel injector equivalence ratio was increased to 0.72.

Contrasting dynamics of leaf potential and gas exchange during progressive drought cycles and recovery in Amorpha fruticosa and Robinia pseudoacacia.

Science.gov (United States)

Yan, Weiming; Zheng, Shuxia; Zhong, Yangquanwei; Shangguan, Zhouping

2017-06-30

Leaf gas exchange is closely associated with water relations; however, less attention has been given to this relationship over successive drought events. Dynamic changes in gas exchange and water potential in the seedlings of two woody species, Amorpha fruticosa and Robinia pseudoacacia, were monitored during recurrent drought. The pre-dawn leaf water potential declined in parallel with gas exchange in both species, and sharp declines in gas exchange occurred with decreasing water potential. A significant correlation between pre-dawn water potential and gas exchange was observed in both species and showed a right shift in R. pseudoacacia in the second drought. The results suggested that stomatal closure in early drought was mediated mainly by elevated foliar abscisic acid (ABA) in R. pseudoacacia, while a shift from ABA-regulated to leaf-water-potential-driven stomatal closure was observed in A. fruticosa. After re-watering, the pre-dawn water potential recovered quickly, whereas stomatal conductance did not fully recover from drought in R. pseudoacacia, which affected the ability to tightly control transpiration post-drought. The dynamics of recovery from drought suggest that stomatal behavior post-drought may be restricted mainly by hydraulic factors, but non-hydraulic factors may also be involved in R. pseudoacacia.

Fundamentals of gas particle flow

CERN Document Server

Rudinger, G

1980-01-01

Fundamentals of Gas-Particle Flow is an edited, updated, and expanded version of a number of lectures presented on the "Gas-Solid Suspensions” course organized by the von Karman Institute for Fluid Dynamics. Materials presented in this book are mostly analytical in nature, but some experimental techniques are included. The book focuses on relaxation processes, including the viscous drag of single particles, drag in gas-particles flow, gas-particle heat transfer, equilibrium, and frozen flow. It also discusses the dynamics of single particles, such as particles in an arbitrary flow, in a r

Molecular mechanism of adsorption/desorption hysteresis: dynamics of shale gas in nanopores

Science.gov (United States)

Chen, Jie; Wang, FengChao; Liu, He; Wu, HengAn

2017-01-01

Understanding the adsorption and desorption behavior of methane has received considerable attention since it is one of the crucial aspects of the exploitation of shale gas. Unexpectedly, obvious hysteresis is observed from the ideally reversible physical sorption of methane in some experiments. However, the underlying mechanism still remains an open problem. In this study, Monte Carlo (MC) and molecular dynamics (MD) simulations are carried out to explore the molecular mechanisms of adsorption/desorption hysteresis. First, a detailed analysis about the capillary condensation of methane in micropores is presented. The influence of pore width, surface strength, and temperature on the hysteresis loop is further investigated. It is found that a disappearance of hysteresis occurs above a temperature threshold. Combined with the phase diagram of methane, we explicitly point out that capillary condensation is inapplicable for the hysteresis of shale gas under normal temperature conditions. Second, a new mechanism, variation of pore throat size, is proposed and studied. For methane to pass through the throat, a certain energy is required due to the repulsive interaction. The required energy increases with shrinkage of the throat, such that the originally adsorbed methane cannot escape through the narrowed throat. These trapped methane molecules account for the hysteresis. Furthermore, the hysteresis loop is found to increase with the increasing pressure and decreasing temperature. We suggest that the variation of pore throat size can explain the adsorption/desorption hysteresis of shale gas. Our conclusions and findings are of great significance for guiding the efficient exploitation of shale gas.

Dynamic simulation of a pilot scale vacuum gas oil hydrocracking unit by the space-time CE/SE method

Energy Technology Data Exchange (ETDEWEB)

Sadighi, S.; Ahmad, A. [Institute of Hydrogen Economy, Universiti Teknologi Malaysia, Johor Bahru (Malaysia); Shirvani, M. [Faculty of Chemical Engineering, University of Science and Technology, Tehran (Iran, Islamic Republic of)

2012-05-15

This work introduces a modified space-time conservation element/solution element (CE/SE) method for the simulation of the dynamic behavior of a pilot-scale hydrocracking reactor. With this approach, a four-lump dynamic model including vacuum gas oil (VGO), middle distillate, naphtha and gas is solved. The proposed method is capable of handling the stiffness of the partial differential equations resulting from the hydrocracking reactions. To have a better judgment, the model is also solved by the finite difference method (FDM), and the results from both approaches are compared. Initially, the absolute average deviation of the cold dynamic simulation using the CE/SE approach is 8.98 %, which is better than that obtained using the FDM. Then, the stability analysis proves that for achieving an appropriate response from the dynamic model, the Courant number, which is a function of the time step size, mesh size and volume flow rate through the catalytic bed, should be less than 1. Finally, it is found that, following a careful selection of these parameters, the CE/SE solutions to the hydrocracking model can produce higher accuracy than the FDM results. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cloud fluid models of gas dynamics and star formation in galaxies

Science.gov (United States)

Struck-Marcell, Curtis; Scalo, John M.; Appleton, P. N.

1987-01-01

The large dynamic range of star formation in galaxies, and the apparently complex environmental influences involved in triggering or suppressing star formation, challenges the understanding. The key to this understanding may be the detailed study of simple physical models for the dominant nonlinear interactions in interstellar cloud systems. One such model is described, a generalized Oort model cloud fluid, and two simple applications of it are explored. The first of these is the relaxation of an isolated volume of cloud fluid following a disturbance. Though very idealized, this closed box study suggests a physical mechanism for starbursts, which is based on the approximate commensurability of massive cloud lifetimes and cloud collisional growth times. The second application is to the modeling of colliding ring galaxies. In this case, the driving processes operating on a dynamical timescale interact with the local cloud processes operating on the above timescale. The results is a variety of interesting nonequilibrium behaviors, including spatial variations of star formation that do not depend monotonically on gas density.

Longitudinal and transverse dynamics of ions from residual gas in an electron accelerator

Science.gov (United States)

Gamelin, A.; Bruni, C.; Radevych, D.

2018-05-01

The ion cloud produced from residual gas in an electron accelerator can degrade machine performances and produce instabilities. The ion dynamics in an accelerator is governed by the beam-ion interaction, magnetic fields and eventual mitigation strategies. Due to the fact that the beam has a nonuniform transverse size along its orbit, the ions move longitudinally and accumulate naturally at some points in the accelerator. In order to design effective mitigation strategies it is necessary to understand the ion dynamics not only in the transverse plane but also in the longitudinal direction. After introducing the physics behind the beam-ion interaction, we show how to get accumulation points for a realistic electron storage ring lattice. Simulations of the ion cloud dynamics, including the effect of magnetic fields on the ions, clearing electrodes and clearing gaps are shown. Longitudinal ion trapping due to the magnetic mirror effect in the dipole fringe fields is also detailed. Finally, the effectiveness of clearing electrode using longitudinal clearing fields is discussed and compared to clearing electrodes producing transverse field only.

Analysis of natural gas supply strategies at Fort Drum

International Nuclear Information System (INIS)

Stucky, D.J.; Shankle, S.A.; Anderson, D.M.

1992-07-01

This analysis investigates strategies for Fort Drum to acquire a reliable natural gas supply while reducing its gas supply costs. The purpose of this study is to recommend an optimal supply mix based on the life-cycle costs of each strategy analyzed. In particular, this study is intended to provide initial guidance as to whether or not the building and operating of a propane-air mixing station is a feasible alternative to the current gas acquisition strategy. The analysis proceeded by defining the components of supply (gas purchase, gas transport, supplemental fuel supply); identifying alternative options for each supply component; constructing gas supply strategies from different combinations of the options available for each supply component and calculating the life-cycle costs of each supply strategy under a set of different scenarios reflecting the uncertainty of future events

Oil and gas operational and policy issues in the UK

International Nuclear Information System (INIS)

Howard, D.

1992-01-01

The method of arriving at monthly values under Schedule 3 OTA 1975 applies to all oil which can include LPG and condensate as well as crude oil and gas. The majority of crude oil is now sold spot and in 1987 the method of arriving at monthly values was amended better to reflect this aspect of the crude oil market. The UK gas market was such that the proceeds of sale of large amounts of natural gas were exempt from PRT under Section 10 OTA 1975 and very little gas was disposed of other than at arms length to British Gas. British Gas no longer buys virtually all gas produced from the UK Continental Shelf and neither does it sell all the gas used by UK customers. The use of natural gas to generate electricity has opened up a new market for UK landed gas. How do these changes affect gas valuation.?. (Author)

“Greenwashing gas: Might a ‘transition fuel’ label legitimize carbon-intensive natural gas development?”

International Nuclear Information System (INIS)

Stephenson, Eleanor; Doukas, Alexander; Shaw, Karena

2012-01-01

Natural gas is widely considered to be the crucial “bridging fuel” in the transition to the low-carbon energy systems necessary to mitigate climate change. This paper develops a case study of the shale gas industry in British Columbia (BC), Canada to evaluate this assumption. We find that the transition fuel argument for gas development in BC is unsubstantiated by the best available evidence. Emissions factors for shale gas and LNG remain poorly characterized and contested in the academic literature, and context-specific factors have significant impacts on the lifecycle emissions of shale gas but have not been evaluated. Moreover, while the province has attempted to frame natural gas development within its ambitious climate change policy, this framing misrepresents substantive policy on gas production. The “transition fuel” and “climate solution” labels applied to development by the BC provincial government risk legitimizing carbon-intensive gas development. We argue that policy makers in BC and beyond should abandon the “transition fuel” characterization of natural gas. Instead, decision making about natural gas development should proceed through transparent engagement with the best available evidence to ensure that natural gas lives up to its best potential in supporting a transition to a low-carbon energy system. - Highlights: ► Transition fuel discourse may greenwash gas development. ► Gaps in research obscure emissions factors for LNG and shale gas. ► Climate solution label for shale gas and LNG development in BC is unsubstantiated.

Control of power plants and power systems. Proceedings

International Nuclear Information System (INIS)

Canales-Ruiz, R.

1996-01-01

The 88 papers in this volume constitute the proceedings of the International Federation of Automatic Control Symposium held in Mexico in 1995. The broad areas which they cover are: self tuning control; power plant operations; dynamic stability; fuzzy logic applications; power plants modelling; artificial intelligence applications; power plants simulation; voltage control; control of hydro electric units; state estimation; fault diagnosis and monitoring systems; system expansion and operation planning; security assessment; economic dispatch and optimal load flow; adaptive control; distribution; transient stability and preventive control; modelling and control of nuclear plant; knowledge data bases for automatic learning methods applied to power system dynamic security assessment; control of combined cycle units; power control centres. Separate abstracts have been prepared for the three papers relating to nuclear power plants. (UK)

Local and nonlocal advected invariants and helicities in magnetohydrodynamics and gas dynamics I: Lie dragging approach

International Nuclear Information System (INIS)

Webb, G M; Dasgupta, B; McKenzie, J F; Hu, Q; Zank, G P

2014-01-01

In this paper advected invariants and conservation laws in ideal magnetohydrodynamics (MHD) and gas dynamics are obtained using Lie dragging techniques. There are different classes of invariants that are advected or Lie dragged with the flow. Simple examples are the advection of the entropy S (a 0-form), and the conservation of magnetic flux (an invariant 2-form advected with the flow). The magnetic flux conservation law is equivalent to Faraday's equation. The gauge condition for the magnetic helicity to be advected with the flow is determined. Different variants of the helicity in ideal fluid dynamics and MHD including: fluid helicity, cross helicity and magnetic helicity are investigated. The fluid helicity conservation law and the cross-helicity conservation law in MHD are derived for the case of a barotropic gas. If the magnetic field lies in the constant entropy surface, then the gas pressure can depend on both the entropy and the density. In these cases the conservation laws are local conservation laws. For non-barotropic gases, we obtain nonlocal conservation laws for fluid helicity and cross helicity by using Clebsch variables. These nonlocal conservation laws are the main new results of the paper. Ertel's theorem and potential vorticity, the Hollman invariant, and the Godbillon–Vey invariant for special flows for which the magnetic helicity is zero are also discussed. (paper)

Conference Proceedings: The Quest for gas: tapping additional supplies for a growing market

International Nuclear Information System (INIS)

2000-01-01

The two-day conference attracted 375 attendees from 19 U.S. states, 10 Canadian provinces and territories and several delegates from Europe. The conference reviewed the supply picture in Western Canada and the U.S., the market outlook with special reference to the robust electricity and industrial market, the outlook on gas prices and how the recent high prices impact on gas producers, royalty owners, industrial process users, the expansion of frontier gas, and competing sources of electrical generation, mainly existing coal and nuclear plants. The focus of the discussions centered on the so-called '30 Tcf vision' the recent National Petroleum Council Study in the United States. Further integration of the US and Canadian gas industry, primarily in the area of gas supply, was predicted. Evidence for this integration is the tremendous expansion of the role of frontier gas supplies from the Gulf of Mexico, LNG and coal seam gas in the USA and from the Scotian Shelf, the Liard Valley, north of the sixtieth parallel, Alaska's North Slope and Canada's Mackenzie Delta, to meet North American market demand. A resurgence in the role of large companies was also predicted, displacing the variety of independents, large and small, that have sprung up during the past decade

Proceedings of the natural gas RD&D contractors review meeting, Volume II

Energy Technology Data Exchange (ETDEWEB)

Malone, R.D. [ed.

1995-04-01

This is volume II of papers which were presented at the natural gas RD&D contractors review meeting. Topics include: natural gas upgrading, storage, well drilling, completion, and stimulation. Individual papers were processed separately for the United States Department of Energy databases.

New challenges in gas

Energy Technology Data Exchange (ETDEWEB)

Mandil, C. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Chabrelie, M.F. [Cedigaz, 92 - Rueil Malmaison (France); Streicher, C. [Prosernat, 92 - Paris la Defense (France)] [and others

2003-07-01

New developments in the area of gas treatment will be to a large extent driven by the need to find appropriate solutions to the fundamental need of sustainable development. New gas treatment processes are developed with the aim to minimise contaminant emissions and meet most stringent environmental specifications. A new major challenge for the industry will be to implement new cost effective technologies for reducing CO{sub 2} emissions. Industry has also to minimise its costs, and therefore, in order to ensure at the same time a better protection of the environment and a better safety, it is necessary to innovate. The purpose of this seminar is precisely to identify better the innovations which are required in the area of gas treatment. These proceedings comprise 8 papers and a summary of the contributions to a round-table discussion dealing with the options for CO{sub 2} capture and sequestration. The presentations treat of: the future prospects for the gas industry (M.F. Chabrelie, Cedigaz); the solutions for offshore gas treatment (C. Streicher, Prosernat); gas treatment with membranes (H. Meyer, GTI); the Axens Multibed{sub TM} technology for natural gas treatment (G. Jochem, Axens); the potentials and applications for the Propure co-current contactors (F.P. Nilsen, ProPure); the production of very-sour and super-sour large gas reserves: the new challenges (F. Lallemand, TotalFinaElf); Hybrisol, a new gas treatment process for sour natural gases (F. Lecomte, IFP); and the conception and building of large acid-gas removal units (J. Castel, Technip-Coflexip). (J.S.)

Proceeding of the Sixth Nuclear and Particle Physics Conference (NUPPAC-2007)

International Nuclear Information System (INIS)

2008-11-01

The publication has been set up as proceedings of the Nuclear and Particle Physics conference, the conference contains of the following subjects: High Energy Physics; Nuclear Scattering and Reactions; Nuclear Structure and Spectroscopy; Nuclear and Reactor Physics; Relativistic and Quantum Physics; Plasma and magneto hydro Dynamics; Computation and Simulation and Radiation Measurement and Dosimetry. This conference consists of 642 pages., figs., tabs., refs

Low-momentum dynamic structure factor of a strongly interacting Fermi gas at finite temperature: A two-fluid hydrodynamic description

Science.gov (United States)

Hu, Hui; Zou, Peng; Liu, Xia-Ji

2018-02-01

We provide a description of the dynamic structure factor of a homogeneous unitary Fermi gas at low momentum and low frequency, based on the dissipative two-fluid hydrodynamic theory. The viscous relaxation time is estimated and is used to determine the regime where the hydrodynamic theory is applicable and to understand the nature of sound waves in the density response near the superfluid phase transition. By collecting the best knowledge on the shear viscosity and thermal conductivity known so far, we calculate the various diffusion coefficients and obtain the damping width of the (first and second) sounds. We find that the damping width of the first sound is greatly enhanced across the superfluid transition and very close to the transition the second sound might be resolved in the density response for the transferred momentum up to half of Fermi momentum. Our work is motivated by the recent measurement of the local dynamic structure factor at low momentum at Swinburne University of Technology and the ongoing experiment on sound attenuation of a homogeneous unitary Fermi gas at Massachusetts Institute of Technology. We discuss how the measurement of the velocity and damping width of the sound modes in low-momentum dynamic structure factor may lead to an improved determination of the universal superfluid density, shear viscosity, and thermal conductivity of a unitary Fermi gas.

Modeling of the fluid dynamics and SO{sub 2} absorption in a gas-liquid reactor

Energy Technology Data Exchange (ETDEWEB)

Marocco, L. [Alstom Power Italy, Milan (Italy)

2010-08-01

This paper illustrates a computational fluid dynamic (CFD) model of a counter-current Open Spray Tower desulphurisation reactor and its application in the simulation of a full-scale industrial equipment. The raw flue gas flows upward while a suspension of water and limestone is sprayed downward from different heights. Thereby sulfur dioxide is washed out of the gas. The two-phase gas-liquid flow inside the equipment has been simulated with an Euler-Lagrange approach using a commercial CFD code, while a model for the SO{sub 2} absorption has been developed and implemented in the software through dedicated modules. Physical absorption is modeled using dual-film theory and appropriate empirical and semi-empirical correlations. The aqueous phase chemistry accounts for the instantaneous equilibrium reactions of eight dissolved species into a slurry droplet. The model is used to simulate an industrial plant at different operating conditions. The numerical results are in good agreement with the measured values of pressure drop and sulphur removal efficiency.

Hydrogen Detection With a Gas Sensor Array – Processing and Recognition of Dynamic Responses Using Neural Networks

Directory of Open Access Journals (Sweden)

Gwiżdż Patryk

2015-03-01

Full Text Available An array consisting of four commercial gas sensors with target specifications for hydrocarbons, ammonia, alcohol, explosive gases has been constructed and tested. The sensors in the array operate in the dynamic mode upon the temperature modulation from 350°C to 500°C. Changes in the sensor operating temperature lead to distinct resistance responses affected by the gas type, its concentration and the humidity level. The measurements are performed upon various hydrogen (17-3000 ppm, methane (167-3000 ppm and propane (167-3000 ppm concentrations at relative humidity levels of 0-75%RH. The measured dynamic response signals are further processed with the Discrete Fourier Transform. Absolute values of the dc component and the first five harmonics of each sensor are analysed by a feed-forward back-propagation neural network. The ultimate aim of this research is to achieve a reliable hydrogen detection despite an interference of the humidity and residual gases.

Modelling and simulation of the dynamic performance of a natural-gas turbine flowmeter

Energy Technology Data Exchange (ETDEWEB)

Lopez-Gonzalez, L.M. [Escuela Tecnica Superior de Ingenieria Industrial, Universidad de La Rioja, C/Luis de Ulloa, 20, E-26004 Logrono (La Rioja) (Spain); Sala, J.M.; Gonzalez-Bustamante, J.A. [Escuela Superior de Ingenieros Industriales de Bilbao, Universidad del Pais Vasco, Alameda de Urquijo, s/n 48013 Bilbao (Bizkaia) (Spain); Miguez, J.L. [Universidad de Vigo, Escuela Tecnica Superior de Ingenieros Industriales, C/Lagoas-Marcosende, s/n 36200 Vigo (Pontevedra) (Spain)

2006-11-15

Installations involving fluids often present problems in terms of the dynamic performances of their different parts. These problems can be analysed and dealt with at the design stage. This means that both the technologists who design the thermohydraulic process and those who carry out the regulation and control must be involved in the process from the early stages of the design. In this study, a dynamic model of the behaviour of a gas flowmeter has been developed, based on the laws of conservation of mass, linear momentum, energy and angular momentum. The model has been computerised via a software module. As there is no information available with which to compare the model's behaviour, a continuous rating validation has been carried out, using a comparison with the actual calibration curve of the flowmeter. The results obtained are satisfactory. (author)

Nonequilibrium Spin Dynamics in a Trapped Fermi Gas with Effective Spin-Orbit Interactions

International Nuclear Information System (INIS)

Stanescu, Tudor D.; Zhang Chuanwei; Galitski, Victor

2007-01-01

We consider a trapped atomic system in the presence of spatially varying laser fields. The laser-atom interaction generates a pseudospin degree of freedom (referred to simply as spin) and leads to an effective spin-orbit coupling for the fermions in the trap. Reflections of the fermions from the trap boundaries provide a physical mechanism for effective momentum relaxation and nontrivial spin dynamics due to the emergent spin-orbit coupling. We explicitly consider evolution of an initially spin-polarized Fermi gas in a two-dimensional harmonic trap and derive nonequilibrium behavior of the spin polarization. It shows periodic echoes with a frequency equal to the harmonic trapping frequency. Perturbations, such as an asymmetry of the trap, lead to the suppression of the spin echo amplitudes. We discuss a possible experimental setup to observe spin dynamics and provide numerical estimates of relevant parameters

Proceedings of the second workshop on polarised target materials

International Nuclear Information System (INIS)

Court, G.R.; Niinikoski, T.O.; Cox, S.F.J.; Cragg, D.A.

1980-10-01

The proceedings are reported of a second international workshop which was convened to consider the use of polarised targets in nuclear research and in particular the experimental difficulties imposed by the limitations of target materials with respect to their relatively low hydrogen content and susceptibility to radiation damage. Papers presented were entitled: (1) Introduction and general review. (2) Theory of dynamic nuclear polarisation. (3) Radiation induced paramagnetic centres in organic and inorganic materials. (4) Dynamic nuclear polarisation with radiation induced free radicals. (5) Radiation damage of chemically doped materials. (6) Chemical doping. (7) Techniques and instrumentation. (8) The use of polarised nuclei in physics with neutrons. (9) The use of polarised targets in high energy physics. (U.K.)

Molecular dynamics simulation of chemical vapor deposition of amorphous carbon. Dependence on H/C ratio of source gas

International Nuclear Information System (INIS)

Ito, Atsushi M.; Takayama, Arimichi; Nakamura, Hiroaki; Saito, Seiki; Ohno, Noriyasu; Kajita, Shin

2011-01-01

By molecular dynamics simulation, the chemical vapor deposition of amorphous carbon onto graphite and diamond surfaces was studied. In particular, we investigated the effect of source H/C ratio, which is the ratio of the number of hydrogen atoms to the number of carbon atoms in a source gas, on the deposition process. In the present simulation, the following two source gas conditions were tested: one was that the source gas was injected as isolated carbon and hydrogen atoms, and the other was that the source gas was injected as hydrocarbon molecules. Under the former condition, we found that as the source H/C ratio increases, the deposition rate of carbon atoms decreases exponentially. This exponential decrease in the deposition rate with increasing source H/C ratio agrees with experimental data. However, under the latter molecular source condition, the deposition rate did not decrease exponentially because of a chemical reaction peculiar to the type of hydrocarbon in the source gas. (author)

Thermal fluid dynamic behavior of coolant helium gas in a typical reactor VHTGR channel of prismatic core; Comportamento termofluidodinamico do gas refrigerante helio em um canal topico de reator VHTGR de nucleo prismatico

Energy Technology Data Exchange (ETDEWEB)

Belo, Allan Cavalcante

2016-08-01

The current studies about the thermal fluid dynamic behavior of the VHTGR core reactors of 4{sup th} generation are commonly developed in 3-D analysis in CFD (computational fluid dynamics), which often requires considerable time and complex mathematical calculations for carrying out these analysis. The purpose of this project is to achieve thermal fluid dynamic analysis of flow of gas helium refrigerant in a typical channel of VHTGR prismatic core reactor evaluating magnitudes of interest such as temperature, pressure and fluid velocity and temperature distribution in the wall of the coolant channel from the development of a computer code in MATLAB considering the flow on one-dimensional channel, thereby significantly reducing the processing time of calculations. The model uses three different references to the physical properties of helium: expressions given by the KTA (German committee of nuclear safety standards), the computational tool REFPROP and a set of constant values for the entire channel. With the use of these three references it is possible to simulate the flow treating the gas both compressible and incompressible. The results showed very close values for the interest quantities and revealed that there are no significant differences in the use of different references used in the project. Another important conclusion to be observed is the independence of helium in the gas compressibility effects on thermal fluid dynamic behavior. The study also indicated that the gas undergoes no severe effects due to high temperature variations in the channel, since this goes in the channel at 914 K and exits at approximately 1263 K, which shows the excellent use of helium as a refrigerant fluid in reactor channels VHTGR. The comparison of results obtained in this work with others in the literature served to confirm the effectiveness of the one-dimensional consideration of method of gas flow in the coolant channel to replace the models made in 3-D for the pressure range

Coal liquefaction and gas conversion contractors review conference: Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-11-01

This volume contains 55 papers presented at the conference. They are divided into the following topical sections: Direct liquefaction; Indirect liquefaction; Gas conversion (methane conversion); and Advanced research liquefaction. Papers in this last section deal mostly with coprocessing of coal with petroleum, plastics, and waste tires, and catalyst studies. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

Apparent dynamic contact angle of an advancing gas--liquid meniscus

International Nuclear Information System (INIS)

Kalliadasis, S.; Chang, H.

1994-01-01

The steady motion of an advancing meniscus in a gas-filled capillary tube involves a delicate balance of capillary, viscous, and intermolecular forces. The limit of small capillary numbers Ca (dimensionless speeds) is analyzed here with a matched asymptotic analysis that links the outer capillary region to the precursor film in front of the meniscus through a lubricating film. The meniscus shape in the outer region is constructed and the apparent dynamic contact angle Θ that the meniscus forms with the solid surface is derived as a function of the capillary number, the capillary radius, and the Hamaker's constant for intermolecular forces, under conditions of weak gas--solid interaction, which lead to fast spreading of the precursor film and weak intermolecular forces relative to viscous forces within the lubricating film. The dependence on intermolecular forces is very weak and the contact angle expression has a tight upper bound tan Θ=7.48 Ca 1/3 for thick films, which is independent of the Hamaker constant. This upper bound is in very good agreement with existing experimental data for wetting fluids in any capillary and for partially wetting fluids in a prewetted capillary. Significant correction to the Ca 1/3 dependence occurs only at very low Ca, where the intermolecular forces become more important and tan Θ diverges slightly from the above asymptotic behavior toward lower values

Mining Pribram in science and technology. Proceedings of Session N

International Nuclear Information System (INIS)

1990-01-01

The proceedings contain 50 papers of which 15 have been inputted in INIS. They concern uranium ore leaching, leaching field designing, leaching process optimization, pressure leaching in autoclaves, obtaining zirconium compounds, scandium, rhenium and other elements as by-products in uranium mining, methods of waste solution and gas processing, reclamation of mined areas, experimental studies of interaction of other ores with leaching solutions, methods of processing uranium ores with increased arsenic content, and increasing corrosion resistance of reinforced concrete structures by the action of electric current. (M.D.). 36 figs., 16 tabs., 47 refs

Corrosion And Thermal Processing In Cold Gas Dynamic Spray Deposited Austenitic Stainless Steel Coatings

Science.gov (United States)

2016-06-01

Champagne have demonstrated this use of the cold spray technique in the repair of helicopter mast supports in U.S. Army aircraft, with over 50...Process: Fundamentals and Applications, Champagne , V. K., Ed., Woodhead, Boca Raton, FL Chap. 3. [3] Schiel, J. F., 2014, “The cold gas-dynamic spray... Champagne , V. K., Ed., Woodhead, Boca Raton, FL Chap. 2. [15] Han, W., Meng, X. M., Zhang, J. B., and Zhao, J., 2012, “Elastic modulus of 304 stainless

Proceedings of the natural gas RD&D contractors review meeting, Volume I

Energy Technology Data Exchange (ETDEWEB)

Malone, R.D.

1995-04-01

This report contains papers which were presented at the natural gas contractors review meeting held on April 4-6, 1995. Topics were concerned with resource and reserves, low permeability reservoir characterization, natural fracture detection, drilling, completion, and stimulation, and natural gas upgrading. Individual papers were processed separately for the United States Department of Energy databases.

Study on dynamics of the influence exerted by plasma on gas flow field in non-thermal atmospheric pressure plasma jet

Energy Technology Data Exchange (ETDEWEB)

Qaisrani, M. Hasnain; Xian, Yubin, E-mail: yubin.xian@hotmail.com; Li, Congyun; Pei, Xuekai; Ghasemi, Maede; Lu, Xinpei [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

2016-06-15

In this paper, first, steady state of the plasma jet at different operating conditions is investigated through Schlieren photography with and without applying shielding gas. Second, the dynamic process for the plasma impacting on the gas flow field is studied. When the discharge is ignited, reduction in laminar flow occurs. However, when the gas flow rate is too low or too high, this phenomenon is not obvious. What is more, both frequency and voltage have significant impact on the effect of plasma on the gas flow, but the former is more significant. Shielding gas provides a curtain for plasma to propagate further. High speed camera along with Schlieren photography is utilized to study the impact of plasma on the gas flow when plasma is switched on and off. The transition of the gas flow from laminar to turbulent or vice versa happens right after the turbulent front. It is concluded that appearance and propagation of turbulence front is responsible for the transition of the flow state.

Dynamics of gas-surface interactions atomic-level understanding of scattering processes at surfaces

CERN Document Server

Díez Muniño, Ricardo

2013-01-01

This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level u...

Coherent spin dynamics of an interwell excitonic gas in GaAs/AlGaAs coupled quantum wells

DEFF Research Database (Denmark)

Larionov, A. V.; Bisti, V. E.; Bayer, M.

2006-01-01

The spin dynamics of an interwell exciton gas has been investigated in n-i-n GaAs/AlGaAs coupled quantum wells. The time evolution kinetics of the interwell exciton photoluminescence has been measured under resonant excitation of the 1s heavy-hole intrawell exciton, using a pulsed tunable laser...

Diagnosis of dynamic systems based on explicit and implicit behavioural models: an application to gas turbines in Esprit Project Tiger

Energy Technology Data Exchange (ETDEWEB)

Trave-Massuyes, L. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Milne, R.

1995-12-31

We are interested in the monitoring and diagnosis of dynamic systems. In our work, we are combining explicit temporal models of the behaviour of a dynamic system with implicit behavioural models supporting model based approaches. This work is drive by the needs of and applied to, two gas turbines of very different size and power. In this paper we describe the problems of building systems for these domains and illustrate how we have developed a system where these two approaches complement each other to provide a comprehensive fault detection and diagnosis system. We also explore the strengths and weaknesses of each approach. The work described here is currently working continuously, on line to a gas turbine in a major chemical plant. (author) 24 refs.

Diagnosis of dynamic systems based on explicit and implicit behavioural models: an application to gas turbines in Esprit Project Tiger

Energy Technology Data Exchange (ETDEWEB)

Trave-Massuyes, L [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Milne, R

1996-12-31

We are interested in the monitoring and diagnosis of dynamic systems. In our work, we are combining explicit temporal models of the behaviour of a dynamic system with implicit behavioural models supporting model based approaches. This work is drive by the needs of and applied to, two gas turbines of very different size and power. In this paper we describe the problems of building systems for these domains and illustrate how we have developed a system where these two approaches complement each other to provide a comprehensive fault detection and diagnosis system. We also explore the strengths and weaknesses of each approach. The work described here is currently working continuously, on line to a gas turbine in a major chemical plant. (author) 24 refs.

Selectivity of the gas sensor based on the 50%In2O3-50%Ga2O3 thin film in dynamic mode of operation

Science.gov (United States)

Demin, I. E.; Kozlov, A. G.

2018-01-01

The article considers the gas sensor with the sensitive layer based on the 50%In2O3 -50%Ga2O3 thin film. The temperature and concentration dependencies of gas-induced resistance response of this sensor and the dynamical dependencies of its resistance response on the test gases in air are investigated. The test gases were ethanol, acetone, ammonia and liquefied petroleum gas. The information parameters of the sensor in the dynamical mode of operation were considered to improve its selectivity. The presented results show that the selectivity of the sensor in this mode may be improved by using the following information parameters: gas-induced resistance response in steady state, activation energy of the response and pre-exponential factor of the temperature dependence of the response time constant.

16 CFR 3.2 - Nature of adjudicative proceedings.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Nature of adjudicative proceedings. 3.2... RULES OF PRACTICE FOR ADJUDICATIVE PROCEEDINGS Scope of Rules; Nature of Adjudicative Proceedings § 3.2 Nature of adjudicative proceedings. Adjudicative proceedings are those formal proceedings conducted under...

Fluid dynamics characterization of riser in a FCC cold flow model using gas radiotracer

International Nuclear Information System (INIS)

Santos, Valdemir A. dos; Lima, Emerson A.O.

2013-01-01

Was carried out the characterization of a diameter small riser of a cold flow model of a circulating fluidized bed (CFB), with aid of a radioactive tracer. Compressed air and catalytic cracking of petroleum flow through solids pneumatic transport regime, made of transparent material (glass, acrylic, PVC, polycarbonate) for study of problems in Fluid Catalytic Cracking (FCC) unit and development of methods of measurement of fluid dynamic parameters. The CFB model consisted of a mixer component solid-gas (compressed air at 25 deg C and 200 kN/m 2 ; cracking catalyst with an average diameter of 72μm and specific mass of 1,500 kg/m 3 ), comprising a riser pipe glass 0.02m internal diameter and 1.8m height, a gas solid separation vessel by flash effect, with the filter in the gas outlet, and a return column (a glass tube with an internal diameter of 0.0254m) to redirect the catalyst for the riser base. Recorded data allowed studies on residence time distribution of the gaseous phase in the riser, with the identification and characterization of the flow of gas-solid components in the CFB riser of small diameter. A plug flow type with deviations due to back mixing of catalyst close to the walls, associated with the density difference between this component was observed. (author)

Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.

Directory of Open Access Journals (Sweden)

Yoshiyuki Fukuoka

Full Text Available Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency, breath-by-breath ventilation (V̇E and gas exchange (CO2 output (V̇CO2 and O2 uptake (V̇O2 responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min. The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW was significantly greater than that during sinusoidal cycling (SC, and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward and muscle afferent feedback.

APPLICATION OF GAS DYNAMICAL FRICTION FOR PLANETESIMALS. II. EVOLUTION OF BINARY PLANETESIMALS

Energy Technology Data Exchange (ETDEWEB)

Grishin, Evgeni; Perets, Hagai B. [Physics Department, Technion—Israel Institute of Technology, Haifa, 3200003 (Israel)

2016-04-01

One of the first stages of planet formation is the growth of small planetesimals and their accumulation into large planetesimals and planetary embryos. This early stage occurs long before the dispersal of most of the gas from the protoplanetary disk. At this stage gas–planetesimal interactions play a key role in the dynamical evolution of single intermediate-mass planetesimals (m{sub p} ∼ 10{sup 21}–10{sup 25} g) through gas dynamical friction (GDF). A significant fraction of all solar system planetesimals (asteroids and Kuiper-belt objects) are known to be binary planetesimals (BPs). Here, we explore the effects of GDF on the evolution of BPs embedded in a gaseous disk using an N-body code with a fiducial external force accounting for GDF. We find that GDF can induce binary mergers on timescales shorter than the disk lifetime for masses above m{sub p} ≳ 10{sup 22} g at 1 au, independent of the binary initial separation and eccentricity. Such mergers can affect the structure of merger-formed planetesimals, and the GDF-induced binary inspiral can play a role in the evolution of the planetesimal disk. In addition, binaries on eccentric orbits around the star may evolve in the supersonic regime, where the torque reverses and the binary expands, which would enhance the cross section for planetesimal encounters with the binary. Highly inclined binaries with small mass ratios, evolve due to the combined effects of Kozai–Lidov (KL) cycles with GDF which lead to chaotic evolution. Prograde binaries go through semi-regular KL evolution, while retrograde binaries frequently flip their inclination and ∼50% of them are destroyed.

Gas production and storage - gas transport and supply. Colloquium 7th conference proceedings; Gasfoerderung und Gasspeicherung - Gastransport und Gasversorgung. Kolloquium 7. Tagungsband

Energy Technology Data Exchange (ETDEWEB)

Wagner, S. [ed.] [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Bohrtechnik und Fluidbergbau; Koeckritz, V. [comp.

1999-07-01

The colloquium papers discuss trends in gas supply engineering, automtion of gas storages, liberalisation of the gas market, and gas management systems in integrated supply systems. Rock-mechanical problems of natural gas storage caverns are mentioned. Further subjects are gas extraction rom coal seams, power generation from gas in fuel cells, a model for blowout calculation of real gases, and vortex tubes in gas pressure reduction systems. 19 contributions have been recorded separately in this database. [German] Die einzelnen Beitraege des Kolloquiums befassen sich mit den Entwicklungen in der Gasversorgungstechnik, mit der Automatisierung von Gasspeichern, mit der Liberalisierung des Gasmarktes sowie mit Gasmanagementsystemen in Verbundnetzen. Neben der Gasspeicherung in Porenspeichern und Salzkavernen, deren Sicherheit und der Soleversenkung, sind Betraege zu gebirgsmechanischen Problemen in Erdgasspeicherkavernen enthalten. Weitere Themen sind die Gasfoerderung aus Steinkohlefloezen, die Energieerzeugung aus Gas in Brennstoffzellen, ein Modell zur Blowout-Berechnung realer Gase sowie Wirbelrohre in Anlagen zur Gasdruckminderung. Fuer die Datenbank Energy wurden 19 Beitraege separat aufgenommen.

Beam-gas Background Observations at LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00214737; The ATLAS collaboration; Alici, Andrea; Lazic, Dragoslav-Laza; Alemany Fernandez, Reyes; Alessio, Federico; Bregliozzi, Giuseppe; Burkhardt, Helmut; Corti, Gloria; Guthoff, Moritz; Manousos, Athanasios; Sjoebaek, Kyrre; D'Auria, Saverio

2017-01-01

Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

Increasing the speed of computational fluid dynamics procedure for minimization the nitrogen oxide polution from the premixed atmospheric gas burner

Directory of Open Access Journals (Sweden)

Fotev Vasko G.

2017-01-01

Full Text Available This article presents innovative method for increasing the speed of procedure which includes complex computational fluid dynamic calculations for finding the distance between flame openings of atmospheric gas burner that lead to minimal NO pollution. The method is based on standard features included in commercial computational fluid dynamic software and shortens computer working time roughly seven times in this particular case.

Exact Solution of Gas Dynamics Equations Through Reduced Differential Transform and Sumudu Transform Linked with Pades Approximants

Science.gov (United States)

Rao, T. R. Ramesh

2018-04-01

In this paper, we study the analytical method based on reduced differential transform method coupled with sumudu transform through Pades approximants. The proposed method may be considered as alternative approach for finding exact solution of Gas dynamics equation in an effective manner. This method does not require any discretization, linearization and perturbation.

Facilitating Students' Interaction with Real Gas Properties Using a Discovery-Based Approach and Molecular Dynamics Simulations

Science.gov (United States)

Sweet, Chelsea; Akinfenwa, Oyewumi; Foley, Jonathan J., IV

2018-01-01

We present an interactive discovery-based approach to studying the properties of real gases using simple, yet realistic, molecular dynamics software. Use of this approach opens up a variety of opportunities for students to interact with the behaviors and underlying theories of real gases. Students can visualize gas behavior under a variety of…

Proceedings of the DGMK-conference 'Synthesis gas chemistry'. Authors' manuscripts

Energy Technology Data Exchange (ETDEWEB)

Hoenicke, D.; Kohlpaintner, C.; Luecke, B.; Reschetilowski, W. [eds.

2000-07-01

The main topics of the DGMK-Conference ''Synthesis Gas Chemistry'' were: production of synthesis gas from several educts, new catalysts, Fischer-Tropsch synthesis, hydroformylation, steam reforming and carbonylation.

Gas price policies in Central and Eastern Europe. Papers and proceedings of the Seminar

International Nuclear Information System (INIS)

1996-01-01

The seminar on the topic of gas pricing and its future supply to Central and Eastern European countries was organised by the United Nations Gas Centre, part of the Economic Commission for Europe, and sponsored by the Slovenian gas company Geoplin, the N.V. Nederlandse Gasunie and ABN-AMRO Bank. The purpose was to analyse natural gas pricing as the major prerequisite for further integration of the Eastern, Central and Western European gas markets. Almost 150 representatives of gas industries and government officials of 36 different countries presented and discussed their experiences, know-how and visions on the themes of gas pricing and, in relation to these, future supply options. A total of 19 Central and Eastern European countries were represented, 11 western European countries and two from other parts of the world. The large number of participating countries and the high level of participants present witnessed the general acceptance of the importance of sharing views and information as a step towards further integration of the European gas industry. Establishment of commercial price structures and policies was identified as a main concern of Central and Eastern European countries. At present, in many cases in economies in transition the current end user prices are not sufficient to cover import European border prices. Once introduced, the commercial prices will facilitate a country's diversification, which is not only important for diminishing dependency on one supplier, but its also important for the growth of the European market as a whole. Countries that can rely on a diversified supply will allow themselves to have a larger share of gas in their primary energy supply and will be able to support necessary investment. Future market growth in the European gas market as a whole is of great importance for reducing Europe's environmental burden. Experience over the past 20 years in the western European gas industry demonstrated that the market integration is based

Seed and soil dynamics in shrubland ecosystems: proceedings; 2002 August 12-16; Laramie, WY

Science.gov (United States)

Ann L. Hild; Nancy L. Shaw; Susan E. Meyer; D. Terrance Booth; E. Durant McArthur

2004-01-01

The 38 papers in this proceedings are divided into six sections; the first includes an overview paper and documentation of the first Shrub Research Consortium Distinguished Service Award. The next four sections cluster papers on restoration and revegetation, soil and microsite requirements, germination and establishment of desired species, and community ecology of...

75 FR 30392 - Transparency Provisions of Section 23 of the Natural Gas Act; Notice of Extension of Time

Science.gov (United States)

2010-06-01

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RM07-10-002] Transparency Provisions of Section 23 of the Natural Gas Act; Notice of Extension of Time May 24, 2010. In comments following the March 25, 2010 Technical Conference in the above-referenced proceeding, the Natural Gas Supply...

Design and development of gas cooled reactors with closed cycle gas turbines. Proceedings of a technical committee meeting

International Nuclear Information System (INIS)

1996-08-01

Technological advances over the past fifteen years in the design of turbomachinery, recuperators and magnetic bearings provide the potential for a quantum improvement in nuclear power generation economics through the use of the HTGR with a closed cycle gas turbine. Enhanced international co-operation among national gas cooled reactor programmes in these common technology areas could facilitate the development of this nuclear power concept thereby achieving safety, environmental and economic benefits with overall reduced development costs. This TCM and Workshop was convened to provide the opportunity to review and examine the status of design activities and technology development in national HTGR programmes with specific emphasis on the closed cycle gas turbine, and to identify pathways which take advantage of the opportunity for international co-operation in the development of this concept. Refs, figs, tabs

Design and development of gas cooled reactors with closed cycle gas turbines. Proceedings of a technical committee meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-08-01

Technological advances over the past fifteen years in the design of turbomachinery, recuperators and magnetic bearings provide the potential for a quantum improvement in nuclear power generation economics through the use of the HTGR with a closed cycle gas turbine. Enhanced international co-operation among national gas cooled reactor programmes in these common technology areas could facilitate the development of this nuclear power concept thereby achieving safety, environmental and economic benefits with overall reduced development costs. This TCM and Workshop was convened to provide the opportunity to review and examine the status of design activities and technology development in national HTGR programmes with specific emphasis on the closed cycle gas turbine, and to identify pathways which take advantage of the opportunity for international co-operation in the development of this concept. Refs, figs, tabs.

Augmented switching linear dynamical system model for gas concentration estimation with MOX sensors in an open sampling system.

Science.gov (United States)

Di Lello, Enrico; Trincavelli, Marco; Bruyninckx, Herman; De Laet, Tinne

2014-07-11

In this paper, we introduce a Bayesian time series model approach for gas concentration estimation using Metal Oxide (MOX) sensors in Open Sampling System (OSS). Our approach focuses on the compensation of the slow response of MOX sensors, while concurrently solving the problem of estimating the gas concentration in OSS. The proposed Augmented Switching Linear System model allows to include all the sources of uncertainty arising at each step of the problem in a single coherent probabilistic formulation. In particular, the problem of detecting on-line the current sensor dynamical regime and estimating the underlying gas concentration under environmental disturbances and noisy measurements is formulated and solved as a statistical inference problem. Our model improves, with respect to the state of the art, where system modeling approaches have been already introduced, but only provided an indirect relative measures proportional to the gas concentration and the problem of modeling uncertainty was ignored. Our approach is validated experimentally and the performances in terms of speed of and quality of the gas concentration estimation are compared with the ones obtained using a photo-ionization detector.

SAInt – A novel quasi-dynamic model for assessing security of supply in coupled gas and electricity transmission networks

NARCIS (Netherlands)

Pambour, Kwabena Addo; Cakir Erdener, Burcin; Bolado-Lavin, Ricardo; Dijkema, Gerhard P.J.

2017-01-01

The integration of renewable energy sources into existing electric power systems is connected with an increased interdependence between natural gas and electricity transmission networks. To analyse this interdependence and its impact on security of supply, we developed a novel quasi-dynamic

Natural gas deregulation: have the handcuffs really been removed?

International Nuclear Information System (INIS)

Kelley, T.D.

1995-01-01

The natural gas market in New York State was reviewed and characterized as being very competitive. A brief description of the New York State Electric and Gas Corp. (NYSEG) was given. As regards recent developments, in October 1993, the New York Public Service Commission (NYPSC) instituted a proceeding (93-G-0932) on the restructuring of the gas market. Several guidelines for market restructuring were established as a result. The guidelines were in respect to service to consumers, safety of distribution, environmental implications, consumer concerns, gas rates, regulation, and access for core customers. The speaker noted that these guidelines did not promote deregulation. Competitive issues faced by local gas distributors were enumerated. Among these were (1)service to core and non-core customers (2)transition costs, (3)streaming, (4)unbundling and repackaged services, (5)price differentiation, and (6)small customer aggregation. It was expected that marketers would oppose the Public Service Commission giving local gas distributors additional pricing flexibility

Dynamic measurement of mercury adsorption and oxidation on activated carbon in simulated cement kiln flue gas

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Anker Degn; Windelin, Christian

2012-01-01

of the sulfite converter is short and typically within 2min. Dynamic mercury adsorption and oxidation tests on commercial activated carbons Darco Hg and HOK standard were performed at 150°C using simulated cement kiln gas and a fixed bed reactor system. It is shown that the converter and analyzer system...... are still under development and are investigated in this work. A commercial red brass converter was tested at 180°C and it was found that the red brass chips work in nitrogen atmosphere only, but do not work properly under simulated cement kiln flue gas conditions. Test of the red brass converter using only...... elemental mercury shows that when HCl is present with either SO2 or NOx the mercury measurement after the converter is unstable and lower than the elemental mercury inlet level. The conclusion is that red brass chips cannot fully reduce oxidized mercury to elemental mercury when simulated cement kiln gas...

Materials for advanced power engineering 2010. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Lecomte-Beckers, Jacqueline; Contrepois, Quentin; Beck, Tilmann; Kuhn, Bernd (eds.)

2010-07-01

The 9th Liege Conference on ''Materials for Advanced Power Engineering'' presents the results of the materials related COST Actions 536 ''Alloy Development for Critical Components of Environmentally Friendly Power Plants'' and 538 ''High Temperature Plant Lifetime Extension''. In addition, the broad field of current materials research perspectives for high efficiency, low- and zero- emission power plants and new energy technologies for the next decades are reported. The Conference proceedings are structured as follows: 1. Materials for advanced steam power plants; 2. Gas turbine materials; 3. Materials for nuclear fission and fusion; 4. Solid oxide fuel cells; 5. Corrosion, thermomechanical fatigue and modelling; 6. Zero emission power plants.

Effect of the dynamic pressure on the shock wave structure in a rarefied polyatomic gas

Energy Technology Data Exchange (ETDEWEB)

Taniguchi, Shigeru, E-mail: taniguchi@stat.nitech.ac.jp; Sugiyama, Masaru, E-mail: sugiyama@nitech.ac.jp [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Arima, Takashi, E-mail: tks@stat.nitech.ac.jp [Center for Social Contribution and Collaboration, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Ruggeri, Tommaso, E-mail: tommaso.ruggeri@unibo.it [Department of Mathematics and Research Center of Applied Mathematics (CIRAM), University of Bologna, Bologna (Italy)

2014-01-15

We study the shock wave structure in a rarefied polyatomic gas based on a simplified model of extended thermodynamics in which the dissipation is due only to the dynamic pressure. In this case the differential system is very simple because it is a variant of Euler system with a new scalar equation for the dynamic pressure [T. Arima, S. Taniguchi, T. Ruggeri, and M. Sugiyama, Phys. Lett. A 376, 2799–2803 (2012)]. It is shown that this theory is able to describe the three types of the shock wave structure observed in experiments: the nearly symmetric shock wave structure (Type A, small Mach number), the asymmetric structure (Type B, moderate Mach number), and the structure composed of thin and thick layers (Type C, large Mach number)

Dynamics of leaf gas exchange, xylem and phloem transport, water potential and carbohydrate concentration in a realistic 3-D model tree crown.

Science.gov (United States)

Nikinmaa, Eero; Sievänen, Risto; Hölttä, Teemu

2014-09-01

Tree models simulate productivity using general gas exchange responses and structural relationships, but they rarely check whether leaf gas exchange and resulting water and assimilate transport and driving pressure gradients remain within acceptable physical boundaries. This study presents an implementation of the cohesion-tension theory of xylem transport and the Münch hypothesis of phloem transport in a realistic 3-D tree structure and assesses the gas exchange and transport dynamics. A mechanistic model of xylem and phloem transport was used, together with a tested leaf assimilation and transpiration model in a realistic tree architecture to simulate leaf gas exchange and water and carbohydrate transport within an 8-year-old Scots pine tree. The model solved the dynamics of the amounts of water and sucrose solute in the xylem, cambium and phloem using a fine-grained mesh with a system of coupled ordinary differential equations. The simulations predicted the observed patterns of pressure gradients and sugar concentration. Diurnal variation of environmental conditions influenced tree-level gradients in turgor pressure and sugar concentration, which are important drivers of carbon allocation. The results and between-shoot variation were sensitive to structural and functional parameters such as tree-level scaling of conduit size and phloem unloading. Linking whole-tree-level water and assimilate transport, gas exchange and sink activity opens a new avenue for plant studies, as features that are difficult to measure can be studied dynamically with the model. Tree-level responses to local and external conditions can be tested, thus making the approach described here a good test-bench for studies of whole-tree physiology.

Gas dynamics in the central cavity of HYLIFE-II reactor

International Nuclear Information System (INIS)

Chen, X.M.; Schrock, V.E.; Peterson, P.F.; Colella, P.

1992-01-01

In a HYLIFE-II ICF reactor, the microfusion of the D-T capsule in the center of the chamber produces X-rays that can ablate a thin layer off the liquid blanket which protects the first structural wall Thisablated material will implode toward the center line of the central cavity due to the initial vacuum and cylindrical geometry, and then rebound back to the liquid blanket vent through it and exert a pressure ''impulse'' onto the structural wall. The initial ablation occurs in a very short period with very small characteristic length and the implosion and rebounding processes feature very high pressures and temperatures. The proper design of the chamber relies on the reasonably accurate analysis of the gas dynamics in the central cavity and the gas-liquid interaction. In this paper, a second order Godunov numerical method is used to solve the compressible flow equations in the central cavity. The rarefaction and shock phenomena are very well captured by the numerical calculation. The equation of state for Flibe vapor is used in the calculation along with the parameters for the HYLIFE-II design. Since the radiation transport has not yet been included in the current calculations, the vapor possesses higher energy and therefore temperature. The total mass vaporized will also be underestimated in the later time of the calculation. The incorporation of a radiation calculation into this code is our next goal

CAS CERN Accelerator School. Synchrotron radiation and free electron lasers. Proceedings

International Nuclear Information System (INIS)

Turner, S.

1998-01-01

These proceedings present the lectures given at the tenth specialised course organised by the CERN Accelerator School (CAS), the topic this time being 'Synchrotron Radiation and Free-electron Lasers'. A similar course was already given at Chester, UK in 1989 and whose proceedings were published as CERN 90-03. However, recent progress in this field has been so rapid that it became urgent to present a revised version of the course. Starting with a review of the characteristics of synchrotron radiation there follows introductory lectures on electron dynamics in storage rings, beam insertion devices, and beam current and radiation brightness limits. These themes are then developed with more detailed lectures on lattices and emittance, wigglers and undulators, current limitations, beam lifetime and quality, diagnostics and beam stability. Finally lectures are presented on linac and storage ring free-electron lasers. (orig.)

Present status of rarefied gas dynamics approach to the structure of a laser-induced evaporating jet

International Nuclear Information System (INIS)

Cercignani, C.

1980-01-01

With reference to the relation between the state of the surface and the measurements downstream in the dynamic laser pulse technique, the problems arising in connection with the study of the structure of a jet evaporating into a vacuum are investigated. Particular attention is paid to the following aspects gas surface interaction, internal degrees of freedom, presence of more than one species, chemical reactions

Natural Gas and the Transformation of the U.S. Energy Sector: Electricity

Energy Technology Data Exchange (ETDEWEB)

Logan, Jeffrey [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heath, Garvin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Paranhos, Elizabeth [Univ. of Colorado, Boulder, CO (United States); Boyd, William [Univ. of Colorado, Boulder, CO (United States); Carlson, Ken [Colorado State Univ., Fort Collins, CO (United States)

2012-11-01

Domestic natural gas production was largely stagnant from the mid-1970s until about 2005. However, beginning in the late 1990s, advances linking horizontal drilling techniques with hydraulic fracturing allowed drilling to proceed in shale and other formations at much lower cost. The result was a slow, steady increase in unconventional gas production. The Joint Institute for Strategic Energy Analysis (JISEA) designed this study to address four related key questions, which are a subset from the wider dialogue on natural gas; regarding the life cycle greenhouse gas (GHG) emissions associated with shale gas compared to conventional natural gas and other fuels used to generate electricity; existing legal and regulatory frameworks governing unconventional gas development at federal, state, and local levels, and changes in response to the rapid industry growth and public concerns; natural gas production companies changing their water-related practices; and demand for natural gas in the electric sector.

Proceedings of the Fourth Compton Symposium. Proceedings

International Nuclear Information System (INIS)

Dermer, C.D.; Strickman, M.S.; Kurfess, J.D.

1997-01-01

These proceedings represent the papers presented at the Fourth Compton Symposium held in Williamsburg, Virginia in April, 1997. This symposium gives the latest development in gamma ray astronomy and summarizes the results obtained by the Compton Gamma Ray Observatory. One of the missions of the Observatory has been the study of physical processes taking place in the most dynamic sites in the Universe, including supernovae, novae, pulsars, black holes, active galaxies, and gamma-ray bursts. The energies covered range from hard X-ray to gamma-ray regions from 15 KeV to 30 GeV. The Burst and Transient Experiment (BASTE) measures brightness variations in gamma-ray bursts and solar flares. The Oriented Scintillation Spectroscopy Experiment (OSSE), measures spectral output of astrophysical sources in the 0.05 to 10 MeV range. The Imaging Compton Telescope (COMPTEL) detects gamma-rays and performs sky survey in the energy range 1 to 30 MeV. The Energetic Gamma Ray Experiment Telescope (EGRET) covers the broadest energy range from 20 MeV to 30 GeV. The papers presented result from all of the above. There were 249 papers presented and out of these, 6 have been abstracted for the Energy, Science and Technology database

Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

Energy Technology Data Exchange (ETDEWEB)

Xiao, Hai [Clemson Univ., SC (United States); Tsai, Hai-Lung [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States)

2014-09-30

This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologies that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.

Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

Science.gov (United States)

Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

2014-10-16

Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

Scaling symmetries, conservation laws and action principles in one-dimensional gas dynamics

International Nuclear Information System (INIS)

Webb, G M; Zank, G P

2009-01-01

Scaling symmetries of the planar, one-dimensional gas dynamic equations with adiabatic index γ are used to obtain Lagrangian and Eulerian conservation laws associated with the symmetries. The known Eulerian symmetry operators for the scaling symmetries are converted to the Lagrangian form, in which the Eulerian spatial position of the fluid element is given in terms of the Lagrangian fluid labels. Conditions for a linear combination of the three scaling symmetries to be a divergence or variational symmetry of the action are established. The corresponding Lagrangian and Eulerian form of the conservation laws are determined by application of Noether's theorem. A nonlocal conservation law associated with the scaling symmetries is obtained by applying a nonlocal symmetry operator to the scaling symmetry-conserved vector. An action principle incorporating known conservation laws using Lagrangian constraints is developed. Noether's theorem for the constrained action principle gives the same formulas for the conserved vector as the classical Noether theorem, except that the Lie symmetry vector field now includes the effects of nonlocal potentials. Noether's theorem for the constrained action principle is used to obtain nonlocal conservation laws. The scaling symmetry conservation laws only apply for special forms of the entropy of the gas.

Hydrodynamic theory for quantum plasmonics: Linear-response dynamics of the inhomogeneous electron gas

DEFF Research Database (Denmark)

Yan, Wei

2015-01-01

We investigate the hydrodynamic theory of metals, offering systematic studies of the linear-response dynamics for an inhomogeneous electron gas. We include the quantum functional terms of the Thomas-Fermi kinetic energy, the von Weizsa¨cker kinetic energy, and the exchange-correlation Coulomb...... energies under the local density approximation. The advantages, limitations, and possible improvements of the hydrodynamic theory are transparently demonstrated. The roles of various parameters in the theory are identified. We anticipate that the hydrodynamic theory can be applied to investigate the linear...... response of complex metallic nanostructures, including quantum effects, by adjusting theory parameters appropriately....

GasFair and Power '99 and the Ontario Competitive Power Conference: proceedings of the 8. annual natural gas and electricity market conference

International Nuclear Information System (INIS)

1999-01-01

The 47 presentations at Enerdata's 1999 annual conference and trade show were divided between the GasFair and Power '99 Natural Gas and Electricity Market Conference, and the Ontario Competitive Power Conference. The four major sessions of GasFair and Power '99 included the: (1) gas track, (2) power track, (3) gas and power, and (4) forums and workshops. In general, the papers reviewed the recent activities in the natural gas and electric power industry in North America. The presentations highlighted the recent changes that are occurring as a result of deregulation and new environmental policies. The North American electric power and natural gas industry are moving towards competition. Most market participants will benefit from this change because it creates a more level playing field. Several papers also discussed issues regarding the long-term outlook for new Canadian gas supplies to eastern and midwest markets. Some of the other topics discussed included issues regarding the impact of basis tradin g, tools of the energy marketer, and the advantages of pipeline planning. The challenges facing Ontario Hydro to diversify their existing power generation and to use natural gas for power generation in order to meet energy demand was also discussed. tabs., figs

Modelling and dynamic simulation of processes with 'MATLAB'. An application of a natural gas installation in a power plant

International Nuclear Information System (INIS)

Gonzalez-Bustamante, J.A.; Sala, J.M.; Lopez-Gonzalez, L.M.; Miguez, J.L.; Flores, I.

2007-01-01

In this paper, it is proposed to incorporate the analysis of the dynamic performance of the process into the design and engineering stage of projects as a means of analysing and resolving this type of problem. The following contributions are made with this objective in mind:(a)The barriers in the way of dynamic analysis are identified. (b)Software tools which make dynamic analysis accessible during the design and engineering phase of the project are proposed. To achieve this goal, modelling and mathematical simulation are used, with the following features: *strict modelling of mass, momentum and energy conservation equations as well as state equations, and *utilisation of the 'Matlab-Simulink' package as the base-software tool. (c)The procedure and tool proposed for dynamic analysis during the design phase should enable these studies to be carried out at a reasonable cost and time for regular industrial projects, and not just for large research projects or nuclear power plants. To complete this paper, we apply our method to a natural gas installation in a power plant. The model is applied to study the transients of a natural gas supply line to a steam-electric power plant. The results of the model have been validated with the actual data on the boiler trip obtained from the distributed control system of a steam-electric power plant

Microgravity experiments on a granular gas of elongated grains

Science.gov (United States)

Harth, K.; Trittel, T.; Kornek, U.; Höme, S.; Will, K.; Strachauer, U.; Stannarius, R.

2013-06-01

Granular gases represent well-suited systems to investigate statistical granular dynamics. The literature comprises numerous investigations of ensembles of spherical or irregularly shaped grains. Mainly computer models, analytical theories and experiments restricted to two dimensions were reported. In three-dimensions, the gaseous state can only be maintained by strong external excitation, e. g. vibrations or electro-magnetic fields, or in microgravity. A steady state, where the dynamics of a weakly disturbed granular gas are governed by particle-particle collisions, is hard to realize with spherical grains due to clustering. We present the first study of a granular gas of elongated cylinders in three dimensions. The mean free path is considerably reduced with respect to spheres at comparable filling fractions. The particles can be tracked in 3D over a sequence of frames. In a homogeneous steady state, we find non-Gaussian velocity distributions and a lack of equipartition of kinetic energy. We discuss the relations between energy input and vibrating plate accelerations. At the request of the authors and the Proceedings Editors, the PDF file of this article has been updated to amend some references present in the PDF file submitted to AIP Publishing. The references affected are listed here:[1] (c) K. Nichol and K. E. Daniels, Phys. Rev. Lett. 108, 018001 (2012); [11] (e) P. G. de Gennes and J. Prost, The Physics of Liquid Crystals, Clarendon Press, Oxford (1993); [17] (b) K. Harth, et al., Phys. Rev. Lett. 110, 144102 (2013).A LaTeX processing error resulted in changes to the authors reference formatting, which was not detected prior to publication. Due apologies are given to the authors for this oversight. The updated article PDF was published on 12 August 2013.

Russian gas in 1993

International Nuclear Information System (INIS)

Wilson, D.C.

1994-01-01

Natural gas output in Russia fell by 3.5% in 1993. This followed decades of rapid growth in production reaching a peak in 1991 and a minor fall in 1993. Gas consumption also peaked in 1991 and fell by 5% over the two following years. The major cause of the decline in consumption is the fall in electricity demand which has accompanied the economic recession. Gas has accounted for about 60% of the reduction in fuel consumption by power stations. Gas consumption by industrial and municipal boilers has also dropped steeply although household and other municipal consumption has increased. The fall in demand does not wholely account for the fall in production, however. Apart from Yamburg, all operational gas fields have now reached the stage of declining production. Government officials are talking tentatively of 1997 as the turning point for the Russian economy and following this, the demand for gas will rise again. It is not certain, however, that the industry will be able to meet the increased demand which is anticipated. Most of the increased production will have to come from new fields in the Yamal Peninsular the development of which is proceeding much more slowly than planned. In the longer term, possibly in the early years of the next century, the Shtokmanovsk gasfield in the Barents Sea may be developed. Other aspects of the Russian gas industry briefly covered are reserves, financing of exploratory drilling, investment, intra-CIS trade and exports and privatisation of the state owned company Garyprom. (UK)

Novel test of modified Newtonian dynamics with gas rich galaxies.

Science.gov (United States)

McGaugh, Stacy S

2011-03-25

The current cosmological paradigm, the cold dark matter model with a cosmological constant, requires that the mass-energy of the Universe be dominated by invisible components: dark matter and dark energy. An alternative to these dark components is that the law of gravity be modified on the relevant scales. A test of these ideas is provided by the baryonic Tully-Fisher relation (BTFR), an empirical relation between the observed mass of a galaxy and its rotation velocity. Here, I report a test using gas rich galaxies for which both axes of the BTFR can be measured independently of the theories being tested and without the systematic uncertainty in stellar mass that affects the same test with star dominated spirals. The data fall precisely where predicted a priori by the modified Newtonian dynamics. The scatter in the BTFR is attributable entirely to observational uncertainty, consistent with a single effective force law.

Canadian natural gas market dynamics and pricing : an update

International Nuclear Information System (INIS)

2002-10-01

This energy market assessment (EMA) report discusses natural gas price formation and describes the current functioning of regional gas markets in Canada. This EMA also describes the factors affecting the price of natural gas in Canada and examines natural gas markets on a region-by region basis. It is shown that as part of an integrated North American market, prices of natural gas in Canada reflect supply and demand factors in both Canada and the United States. During the low oil price period of 1997/1998, high demand for natural gas outpaced the supply because of low drilling and production activity by producers. In response to the increased demand and lower levels of supply, the price of natural gas increased significantly in 1999 and 2000. This was followed by a period of market adjustment. The importance of electronic trading systems for enhancing price discovery was also discussed with reference to how spot and futures markets allow market participants to manage price volatility. It was determined that Canadians have had access to natural gas on terms and conditions equal to export customers, and at equal pricing. In early November 2000, natural gas prices in North American began to rise due to low levels of natural gas in storage. The price shocks were felt unevenly across the North American market. In response to the high prices, consumers conserved energy use, and many industrial users switched to cheaper fuels. By the spring 2001, demand continued to decrease at a time when production was high. These factors contributed to the downward pressure on gas prices. This EMA discusses the structure of market transactions and market adjustment mechanisms. It is presented in the context of the approaching 2002/2003 winter season where the tightening between natural gas supply and demand is expected to result in price volatility. 28 figs

Social licence, corporate social responsibility and coal seam gas: framing the new political dynamics of contestation

International Nuclear Information System (INIS)

Curran, Giorel

2017-01-01

This paper explores the contestation dynamics between the unconventional gas mining sector and its challengers through the prism of the social licence to operate. Social licence is a dominant narrative in the mining sector today and as a signifier of the sector's CSR credentials, the term is an influential one. Its capacity to confer project legitimacy, and hence avoid the risks of community opposition, helps explain why most companies seek to gain one. Today both gas proponents and opponents talk the language of social licence: the former to defend their projects, the latter to challenge them. Yet, beyond rhetoric, the precise meaning of social licence remains elusive. This paper uses a case study of community opposition to primarily coal seam gas projects in an eastern Australian region to explore how the absence of a precise meaning for social licence has created a strategic opportunity space for the industry's opponents to invest social licence with a potent democracy frame. This democracy framing has proved particularly effective as a contestation tool and helps explain the outcomes in this case. - Highlights: • Unconventional gas exploration and mining is becoming increasingly contested. • A key way of managing this contestation is through the social licence to operate. • Both proponents and opponents of gas mining use social licence strategically. • Social licence has become increasingly politicised. • A democratic frame assists the effectiveness of contestation.

America's gas tank : the high cost of Canada's oil and gas export strategy

International Nuclear Information System (INIS)

Price, M.; Bennett, J.

2002-10-01

The high environmental cost of exporting oil and gas from Canada to the United States is discussed. The increased demand for fossil fuels by the United States has coincided with Canada's deregulation of the energy industry and a greater control of Canadian energy companies by American interests. The authors note that most of the oil and gas produced in Canada is exported to the United States, where many of the extraction and production decisions affecting Canadians and the Canadian environment are made. It was cautioned that if the current trend continues, oil and gas development will degrade habitat for endangered species and greenhouse gases will escalate. This is because the fossil fuel industry, particularly the development of Alberta's tar sands, is helping to increase greenhouse gas emissions outside of Canada by selling fossil fuels that are burned outside of Canada. It is recommended that federal and provincial governments in Canada should shift their policies away from fossil fuel production and promote renewable energy production. The United States plans to increase Canadian oil and gas imports in the coming decade, requiring more wells to be drilled and pipelines to carry it. If the fossil fuel industry proceeds with the current plans, greenhouse gas emissions in Canada will grow to 827 million tonnes by 2010, 44 per cent beyond the Kyoto target, having an overall negative impact on public health, wildlife and fresh water supplies. refs., tabs., figs

A three-dimensional thermal and fluid dynamics analysis of a gas cooled subcritical fast reactor driven by a D-T fusion neutron source

International Nuclear Information System (INIS)

Angelo, G.; Andrade, D.A.; Angelo, E.; Carluccio, T.; Rossi, P.C.R.; Talamo, A.

2011-01-01

Highlights: → A thermal fluid dynamics numerical model was created for a gas cooled subcritical fast reactor. → Standard k-ε model, Eddy Viscosity Transport Equation model underestimates the fuel temperature. → For a conservative assumption, SSG Reynolds stress model was chosen. → Creep strength is the most important parameter in fuel design. - Abstract: The entire nuclear fuel cycle involves partitioning classification and transmutation recycling. The usage of a tokamak as neutron sources to burn spent fuel in a gas cooled subcritical fast reactor (GCSFR) reduces the amount of long-lived radionuclide, thus increasing the repository capacity. This paper presents numerical thermal and fluid dynamics analysis for a gas cooled subcritical fast reactor. The analysis aim to determine the operational flow condition for this reactor, and to compare three distinct turbulence models (Eddy Viscosity Transport Equation, standard k-ε and SSG Reynolds stress) for this application. The model results are presented and discussed. The methodology used in this paper was developed to predict the coolant mass flow rate. It can be applied to any other gas cooled reactor.

17 CFR 12.24 - Parallel proceedings.

Science.gov (United States)

2010-04-01

...) Definition. For purposes of this section, a parallel proceeding shall include: (1) An arbitration proceeding... the receivership includes the resolution of claims made by customers; or (3) A petition filed under... any of the foregoing with knowledge of a parallel proceeding shall promptly notify the Commission, by...

Gas dynamics of semidetached binaries

International Nuclear Information System (INIS)

Lubow, S.H.; Shu, F.H.

1975-01-01

We analyze the gas dynamics of semidetached binary systems within the context of the Rohce model. With the adoption of the assumptions that the contact component rotates synchronously and that the flow occurs isothermally with the thermal speed being a small fraction epsilon of the relative orbital speed, Ωd, of the two stars, we show that the steady flow can be formulated in terms of a problem with multiple length scales. Using this concept, we demonstrate the following by semianalytical methods. (1) The escape of material from the surface of the contact component is accomplished by a highly nonisotropic stellar wind which reaches sonic velocities in a neighborhood of the inner Lagrangian point, L1, of size epsilon in comparison with the orbit separation d. (2) This wind throttles into a narrow stram of material which makes a prescribed angle with respect to the line joining the stellar centers ranging from 19 0 5 to 28 0 4 for the full range of possible stellar mass ratios. (3) The width of the stream scales epsilond while its density scales with epsilon -2 M-dot/Ωd 3 , where M-dot is the mass transfer rate. (4) The stream width remains nearly constant over the part of the stream which is nearly straight, and narrows somewhat as the stream curves toward the detached component. (5) If the detached component is smaller than a certain specified size, the stream results in the formation of a disk of material of prescribed size orbiting the detached component in a direct sense. A subsidi []ry issue examined briefly in this paper is the flow mechanism responsible for moving material to the equator of the contact component, and from there to the L1 region where it is lost by the directed stellar wind. Comparisons of our work are made with previous theoretical studies, and some applications are indicated

Modelling the Dynamic Interaction Power System Lamp - Application to High Pressure Mercury Gas Discharge Lamps

OpenAIRE

ZIANE, M.; MEDLES, K.; ADJOUDJ, M.; MILOUA, F.; DAMELINCOURT, J. J.; TILMATINE, A.

2007-01-01

The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp, this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on ...

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

2013-05-15

We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

Insight conference proceedings : Pacific Canada and north coast offshore oil and gas development

International Nuclear Information System (INIS)

2005-01-01

This conference provided a forum for reviewing oil and gas activities in offshore basins around the world and their influence on British Columbia's plans to reopen its offshore to exploration and development. Details on jurisdictional issues were provided along with potential environmental impacts and remedial actions. Speakers with first hand experience in the latest technologies and mitigation measures addressed issues regarding regulatory regimes used in the Arctic offshore and compared them with proposed developments in British Columbia. Issues specific to the Pacific coast were also discussed, such as the current offshore oil and gas moratorium, land use and the views of First Nations and environmental non-governmental organizations. A current industry perspective of offshore oil and gas development was presented with lessons learned from the east coast. The opportunities for constructing liquefied natural gas (LNG) terminals and their associated facilities in the Pacific coast were also presented. This conference featured 14 presentations, of which 3 have been indexed separately for inclusion in this database

Economic analysis of energy system considering the uncertainties of crude oil, natural gas and nuclear utilization employing stochastic dynamic programming

International Nuclear Information System (INIS)

Hasegawa, Keita; Komiyama, Ryoichi; Fujii, Yasumasa

2016-01-01

The paper presents an economic rationality analysis of power generation mix by stochastic dynamic programming considering fuel price uncertainties and supply disruption risks such as import disruption and nuclear power plant shutdown risk. The situation revolving around Japan's energy security adopted the past statistics, it cannot be applied to a quantitative analysis of future uncertainties. Further objective and quantitative evaluation methods are required in order to analyze Japan's energy system and make it more resilient in sight of long time scale. In this paper, the authors firstly develop the cost minimization model considering oil and natural gas price respectively by stochastic dynamic programming. Then, the authors show several premises of model and an example of result with related to crude oil stockpile, liquefied natural gas stockpile and nuclear power plant capacity. (author)

150 Years of vortex dynamics

DEFF Research Database (Denmark)

Aref, Hassan

2010-01-01

An IUTAM symposium with the title of this paper was held on October 12-16, 2008, in Lyngby and Copenhagen, Denmark, to mark the sesquicentennial of publication of Helmholtz's seminal paper on vortex dynamics. This volume contains the proceedings of the Symposium. The present paper provides...

Description of a heat transfer model suitable to calculate transient processes of turbocharged diesel engines with one-dimensional gas-dynamic codes

Energy Technology Data Exchange (ETDEWEB)

Galindo, J.; Lujan, J.M.; Serrano, J.R.; Dolz, V. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Valencia (Spain); Guilain, S. [Renault s.a.s., Lardy (France)

2006-01-15

This paper describes a heat transfer model to be implemented in a global engine 1-D gas-dynamic code to calculate reciprocating internal combustion engine performance in steady and transient operations. A trade off between simplicity and accuracy has been looked for, in order to fit with the stated objective. To validate the model, the temperature of the exhaust manifold wall in a high-speed direct injection (HSDI) turbocharged diesel engine has been measured during a full load transient. In addition, an indirect assessment of the exhaust gas temperature during this transient process has been carried out. The results show good agreement between the measured and modelled data with good accuracy to predict the engine performance. A dual-walled air gap exhaust manifold has been tested in order to quantify the potential of exhaust gas thermal energy saving on engine transient performance. The experimental results together with the heat transfer model have been used to analyse the influence of thermal energy saving on dynamic performance during the load transient of an HSDI turbocharged diesel engine. (author)

Simplified proceeding as a civil procedure model

Directory of Open Access Journals (Sweden)

Олексій Юрійович Зуб

2016-01-01

Full Text Available Currently the directions for the development of modern civil procedural law such as optimization, facilitation, forwarding proceedings promoting the increase of the civil procedure efficiency factor are of peculiar importance. Their results are occurrence and functionality of simplified proceedings system designed to facilitate significantly hearing some categories of cases, promotion of their consideration within reasonable time and reduce legal expenses so far as it is possible. The category “simplified proceedings” in the native science of the procedural law is underexamined. A good deal of scientists-processualists were limited to studying summary (in the context of optimization as a way to improve the civil procedural form, summary proceedings and procedures functioning in terms of the mentioned proceedings, consideration of case in absentia as well as their modification. Among the Ukrainian scientist who studied some aspects of the simplified proceedings are: E. A. Belyanevych, V. I. Bobrik, S. V. Vasilyev, M. V. Verbitska, S. I. Zapara, A. A. Zgama, V. V. Komarov, D. D. Luspenuk, U. V. Navrotska, V. V. Protsenko, T. V. Stepanova, E. A. Talukin, S. Y. Fursa, M. Y. Shtefan others. The problems of the simplified proceedings were studied by the foreign scientists as well, such as: N. Andrews, Y. Y. Grubanon, N. A. Gromoshina, E. P. Kochanenko, J. Kohler, D. I. Krumskiy, E. M. Muradjan, I. V. Reshetnikova, U. Seidel, N. V. Sivak, M. Z. Shvarts, V. V. Yarkov and others. The paper objective is to develop theoretically supported, practically reasonable notion of simplified proceedings in the civil process, and also basing on the notion of simplified proceedings, international experience of the legislative regulation of simplified proceedings, native and foreign doctrine, to distinguish essential features of simplified proceedings in the civil process and to describe them. In the paper we generated the notion of simplified proceedings that

Gas Enrichment at Liquid-Wall Interfaces

NARCIS (Netherlands)

Dammer, S.M.; Lohse, Detlef

2006-01-01

Molecular dynamics simulations of Lennard-Jones systems are performed to study the effects of dissolved gas on liquid-wall and liquid-gas interfaces. Gas enrichment at walls, which for hydrophobic walls can exceed more than 2 orders of magnitude when compared to the gas density in the bulk liquid,

Fluid relabelling symmetries, Lie point symmetries and the Lagrangian map in magnetohydrodynamics and gas dynamics

International Nuclear Information System (INIS)

Webb, G M; Zank, G P

2007-01-01

We explore the role of the Lagrangian map for Lie symmetries in magnetohydrodynamics (MHD) and gas dynamics. By converting the Eulerian Lie point symmetries of the Galilei group to Lagrange label space, in which the Eulerian position coordinate x is regarded as a function of the Lagrange fluid labels x 0 and time t, one finds that there is an infinite class of symmetries in Lagrange label space that map onto each Eulerian Lie point symmetry of the Galilei group. The allowed transformation of the Lagrangian fluid labels x 0 corresponds to a fluid relabelling symmetry, including the case where there is no change in the fluid labels. We also consider a class of three, well-known, scaling symmetries for a gas with a constant adiabatic index γ. These symmetries map onto a modified form of the fluid relabelling symmetry determining equations, with non-zero source terms. We determine under which conditions these symmetries are variational or divergence symmetries of the action, and determine the corresponding Lagrangian and Eulerian conservation laws by use of Noether's theorem. These conservation laws depend on the initial entropy, density and magnetic field of the fluid. We derive the conservation law corresponding to the projective symmetry in gas dynamics, for the case γ = (n + 2)/n, where n is the number of Cartesian space coordinates, and the corresponding result for two-dimensional (2D) MHD, for the case γ = 2. Lie algebraic structures in Lagrange label space corresponding to the symmetries are investigated. The Lie algebraic symmetry relations between the fluid relabelling symmetries in Lagrange label space, and their commutators with a linear combination of the three symmetries with a constant adiabatic index are delineated

Proceedings of the 25th intersociety energy conversion engineering conference

International Nuclear Information System (INIS)

Nelson, P.A.; Schertz, W.W.; Till, R.H.

1990-01-01

This book contains the proceedings of the 25th intersociety energy conversion engineering conference. Volume 1 is organized under the following headings: space power systems requirements and issues, space power systems; space power systems 2; space nuclear power reactors space nuclear reactor technology I; space nuclear reactor technology II; reactor technology; isotopic fueled power systems I, isotopic fueled power systems II, space power automation; space power automation II, space power automation III; space power automation IV; space power automation V; power systems hardware and design selection, power components, pulse power, power management and distribution, power management and distribution II, power management and distribution III; space energy conversion: solar dynamic, space energy conversion: static and dynamic, space solar array technology, advanced space solar cells

Analysis of Specific Features of the Ukrainian Market of Natural Gas Production and Consumption

Directory of Open Access Journals (Sweden)

Lelyuk Oleksiy V.

2013-11-01

Full Text Available The article provides results of the study of specific features of the Ukrainian market of natural gas production and consumption. It analyses dynamics of the specific weight of Ukraine in general volumes of natural gas consumption in the world, dynamics of natural gas consumption in Ukraine during 1990 – 2012 and dependence of natural gas consumption on GDP volumes by the purchasing power parity. It studies the structure of natural gas consumption by regions in 2012 and sectors of economy, resource base of natural gas in Ukraine and also dynamics of established resources of natural gas in Ukraine and dynamics of natural gas production. It analyses base rates of growth of natural gas resources and production in Ukraine. It considers dynamics of import of natural gas into Ukraine and its import prices and also the structure of natural gas import. It identifies the balance of the natural gas market in Ukraine. On the basis of the conducted analysis the article proves that Ukraine is a gas-deficit country of the world, which depends on natural gas import supplies.

A Computational Fluid Dynamics Study of Turbulence, Radiation, and Combustion Models for Natural Gas Combustion Burner

Directory of Open Access Journals (Sweden)

Yik Siang Pang

2018-01-01

Full Text Available This paper presents a Computational Fluid Dynamics (CFD study of a natural gas combustion burner focusing on the effect of combustion, thermal radiation and turbulence models on the temperature and chemical species concentration fields. The combustion was modelled using the finite rate/eddy dissipation (FR/EDM and partially premixed flame models. Detailed chemistry kinetics CHEMKIN GRI-MECH 3.0 consisting of 325 reactions was employed to model the methane combustion. Discrete ordinates (DO and spherical harmonics (P1 model were employed to predict the thermal radiation. The gas absorption coefficient dependence on the wavelength is resolved by the weighted-sum-of-gray-gases model (WSGGM. Turbulence flow was simulated using Reynolds-averaged Navier-Stokes (RANS based models. The findings showed that a combination of partially premixed flame, P1 and standard k-ε (SKE gave the most accurate prediction with an average deviation of around 7.8% of combustion temperature and 15.5% for reactant composition (methane and oxygen. The results show the multi-step chemistry in the partially premixed model is more accurate than the two-step FR/EDM. Meanwhile, inclusion of thermal radiation has a minor effect on the heat transfer and species concentration. SKE turbulence model yielded better prediction compared to the realizable k-ε (RKE and renormalized k-ε (RNG. The CFD simulation presented in this work may serve as a useful tool to evaluate a performance of a natural gas combustor. Copyright © 2018 BCREC Group. All rights reserved Received: 26th July 2017; Revised: 9th October 2017; Accepted: 30th October 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Pang, Y.S., Law, W.P., Pung, K.Q., Gimbun, J. (2018. A Computational Fluid Dynamics Study of Turbulence, Radiation, and Combustion Models for Natural Gas Combustion Burner. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 155-169 (doi:10.9767/bcrec

Post-processing computational fluid dynamic simulations of gas turbine combustor

International Nuclear Information System (INIS)

Sturgess, G.J.; Inko-Tariah, W.P.C.; James, R.H.

1986-01-01

The flowfield in combustors for gas turbine engines is extremely complex. Numerical simulation of such flowfields using computational fluid dynamics techniques has much to offer the design and development engineer. It is a difficult task, but it is one which is now being attempted routinely in the industry. The results of such simulations yield enormous amounts of information from which the responsible engineer has to synthesize a comprehensive understanding of the complete flowfield and the processes contained therein. The complex picture so constructed must be distilled down to the essential information upon which rational development decisions can be made. The only way this can be accomplished successfully is by extensive post-processing of the calculation. Post processing of a simulation relies heavily on computer graphics, and requires the enhancement provided by color. The application of one such post-processor is presented, and the strengths and weaknesses of various display techniques are illustrated

Proceedings of the 23. EFNNE: Meeting of the North and Northeast physicists

International Nuclear Information System (INIS)

2005-01-01

Theoretical and experimental works are presented in these proceedings on the following subjects: particles and fields; atomic and molecular physics; spectroscopy; complex systems; material physics; nanoparticles and nonlinear optics; statistical physics; physics teaching; new materials; lasers; astrophysics, cosmology, nuclear physics and particles; magnetism and magnetic materials; non-linear optics; gravitation and geometric methods; phase transitions; semiconductors; atmosphere physics and geophysics; biological physics; characterization of new materials; complex dynamic systems; instrumentation

49 CFR 511.2 - Nature of adjudicative proceedings.

Science.gov (United States)

2010-10-01

... 49 Transportation 6 2010-10-01 2010-10-01 false Nature of adjudicative proceedings. 511.2 Section... SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ADJUDICATIVE PROCEDURES Scope of Rules; Nature of Adjudicative Proceedings, Definitions § 511.2 Nature of adjudicative proceedings. Adjudicative proceedings...

Modelling the dynamics of the cogeneration power plant gas-air duct

Directory of Open Access Journals (Sweden)

Аnatoliy N. Bundyuk

2014-12-01

Full Text Available Introducing into wide practice the cogeneration power plants (or CHP is one of promising directions of the Ukrainian small-scale power engineering development. Thermal and electric energy generation using the same fuel kind can increase the overall plant efficiency. That makes it appropriate to use CHPs at compact residential areas, isolated industrial enterprises constituting one complex with staff housing area, at sports complexes, etc. The gas-air duct of the cogeneration power plant has been considered as an object of the diesel-generator shaft velocity control. The developed GAD mathematical model, served to analyze the CHP dynamic characteristics as acceleration curves obtained under different external disturbances in the MathWorks MATLAB environment. According to the electric power generation technology requirements a convenient transition process type has been selected, with subsequent identification of the diesel-generator shaft rotation speed control law.

A gas dynamics scheme for a two moments model of radiative transfer

International Nuclear Information System (INIS)

Buet, Ch.; Despres, B.

2007-01-01

We address the discretization of the Levermore's two moments and entropy model of the radiative transfer equation. We present a new approach for the discretization of this model: first we rewrite the moment equations as a Compressible Gas Dynamics equation by introducing an additional quantity that plays the role of a density. After that we discretize using a Lagrange-projection scheme. The Lagrange-projection scheme permits us to incorporate the source terms in the fluxes of an acoustic solver in the Lagrange step, using the well-known piecewise steady approximation and thus to capture correctly the diffusion regime. Moreover we show that the discretization is entropic and preserve the flux-limited property of the moment model. Numerical examples illustrate the feasibility of our approach. (authors)

The multi-physics, user-friendly gas-dynamics code Visual Tsunami 2.0

International Nuclear Information System (INIS)

Debonnel, C. S.; Trubov, L.; Zeballos, C. A.; Peterson, P. F.

2007-01-01

Since the early 1990's, the series of simulation code known as TSUNAMI has been the main tool employed to explore gas dynamics phenomena in thick-liquid protected inertial fusion target chambers. The applicability and user-friendliness of the code was recently extended through a set of MATLAB pre- and post-processing tools and graphical user interfaces [1]. Geometry, initial, and boundary conditions can be specified from within AutoCAD through a set of in-house AutoLISP graphical user interfaces. A novel MATLAB core was recently developed and tested, and is now routinely used with the user-friendly pre- and post-processors [2]. An overview of Visual Tsunami 2.0, the latest version of the code, is presented here. (authors)

GasFair and Power '99 and the Ontario Competitive Power Conference: proceedings of the 8. annual natural gas and electricity market conference

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

The 47 presentations at Enerdata's 1999 annual conference and trade show were divided between the GasFair and Power '99 Natural Gas and Electricity Market Conference, and the Ontario Competitive Power Conference. The four major sessions of GasFair and Power '99 included the: (1) gas track, (2) power track, (3) gas and power, and (4) forums and workshops. In general, the papers reviewed the recent activities in the natural gas and electric power industry in North America. The presentations highlighted the recent changes that are occurring as a result of deregulation and new environmental policies. The North American electric power and natural gas industry are moving towards competition. Most market participants will benefit from this change because it creates a more level playing field. Several papers also discussed issues regarding the long-term outlook for new Canadian gas supplies to eastern and midwest markets. Some of the other topics discussed included issues regarding the impact of basis trading, tools of the energy marketer, and the advantages of pipeline planning. The challenges facing Ontario Hydro to diversify their existing power generation and to use natural gas for power generation in order to meet energy demand was also discussed. tabs., figs.

PREFACE: Introduction to the proceedings of Dynamics Days South America 2010

Science.gov (United States)

Macau, Elbert E. N.; Pereira, Tiago; Prado, Antonio F. B. A.; Turci, Luiz F. R.; Winter, Othon C.

2011-03-01

This proceedings presents selected contributions from the participants of South America Dynamics Days 2011, which was hosted by the National Institute for Space Research (INPE), Brazil, in July 2010. Dynamics Days was founded in 1980 and is the longest standing and most respected international series of meetings devoted to the field of dynamics and nonlinearity. Traditionally it has brought together researchers from a wide range of backgrounds - including physics, biology, engineering, chemistry and mathematics - for interdisciplinary research into nonlinear science. Dynamics Days South America 2010 marked the beginning of the South American branch of Dynamics Days. It brought together, for the first time in South America, researchers from a wide range of backgrounds who share a common interest in the theory and applications of nonlinear dynamics. Thus, South American researchers had a forum to promote regional as well as international scientific and technological exchange and collaboration especially, but not exclusively, on problems that are particularly relevant for the development of science and technology in the South American region. Furthermore, the conference also brought together prominent scientists from around the world to review recent developments in nonlinear science. This conference comprised plenary invited talks, minisymposia, contributed talks and poster sessions. The articles that are compiled here were chosen from among the works that were presented as contributed talks and posters. They represent a good selection which allows one to put issues that were discussed during the conference into perspective. It is possible to evaluate the success of an initiative by using several indices. In relation to attendees, the conference had 311 participants from 22 countries, who presented 341 works. About 86% of the participants came from South American countries. These figures allow one to classify this Dynamics Days conference as that with the greatest

46 CFR 502.61 - Proceedings.

Science.gov (United States)

2010-10-01

...; Pleadings; Motions; Replies § 502.61 Proceedings. (a) Proceedings are commenced by the filing of a complaint... documents, or that the nature of the matter in issue is such that an oral hearing and cross-examination are...

Three-component particle image velocimetry in a generic can-type gas turbine combustor

CSIR Research Space (South Africa)

Meyers, Bronwyn C

2012-11-01

Full Text Available -1 Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy November 2012/ Vol. 226(7) Three-componentParticle Image Velocimetry in a Generic Can-type Gas Turbine Combustor B C Meyers 1, 2* , G C Snedden 1 , J P...

Proceedings of the CERI 2006 natural gas conference : North American markets : fragile, handle with care

International Nuclear Information System (INIS)

2006-01-01

This conference was attended by decision makers throughout the supply chain in the natural gas industry who face the continuing challenges of changes in market mechanisms, pricing options, and transmission alternatives. It provided an opportunity to review issues affecting producers, shippers, marketers, and end-users in an environment of tight energy markets and high, inelastic demand. The constraints on adequate energy supplies are influenced by economic factors, current and future resources, materials, equipment, skilled labour, technology and financial capital. The 8 sessions of the conference dealt with the tight North American gas supply; the slow development of new supplies; resource access issues, including politics and supply security; the geopolitics of natural gas; impacts of high prices on the North American economy; energy industry impacts of high natural gas prices; domestic politics and high natural gas prices; and, radical planning scenarios for the future of natural gas. The conference featured 23 presentations, of which 6 have been catalogued separately for inclusion in this database. refs., tabs., figs

Proceedings of the American Power Conference. Volume 58-I

International Nuclear Information System (INIS)

McBride, A.E.

1996-01-01

This is volume 58-I of the proceedings of the American Power Conference, 1996, Technology for Competition and Globalization. The topics of the papers include power plant DC issues; cost of environmental compliance; advanced coal systems -- environmental performance; technology for competition in dispersed generation; superconductivity technologies for electric utility applications; power generation trends and challenges in China; aging in nuclear power plants; innovative and competitive repowering options; structural examinations, modifications and repairs; electric load forecasting; distribution planning; EMF effects; fuzzy logic and neural networks for power plant applications; electrokinetic decontamination of soils; integrated gasification combined cycle; advances in fusion; cooling towers; relays; plant controls; flue gas desulfurization; waste product utilization; and improved technologies

Influence of surrounding gas, composition and pressure on plasma plume dynamics of nanosecond pulsed laser-induced aluminum plasmas

Directory of Open Access Journals (Sweden)

Mahmoud S. Dawood

2015-10-01

Full Text Available In this article, we present a comprehensive study of the plume dynamics of plasmas generated by laser ablation of an aluminum target. The effect of both ambient gas composition (helium, nitrogen or argon and pressure (from ∼5 × 10−7 Torr up to atmosphere is studied. The time- and space- resolved observation of the plasma plume are performed from spectrally integrated images using an intensified Charge Coupled Device (iCCD camera. The iCCD images show that the ambient gas does not significantly influence the plume as long as the gas pressure is lower than 20 Torr and the time delay below 300 ns. However, for pressures higher than 20 Torr, the effect of the ambient gas becomes important, the shortest plasma plume length being observed when the gas mass species is highest. On the other hand, space- and time- resolved emission spectroscopy of aluminum ions at λ = 281.6 nm are used to determine the Time-Of-Flight (TOF profiles. The effect of the ambient gas on the TOF profiles and therefore on the propagation velocity of Al ions is discussed. A correlation between the plasma plume expansion velocity deduced from the iCCD images and that estimated from the TOF profiles is presented. The observed differences are attributed mainly to the different physical mechanisms governing the two diagnostic techniques.

Natural gas supply and demand in Italy

International Nuclear Information System (INIS)

Comaschi, C.; Di Giulio, E.; Sormani, E.

2007-01-01

This article explores the dynamics between natural gas supply and demand in Italy. In order to supply Italy with increasing volumes of gas, several new pipelines and re gasification plants are expected in the next future, but their implementation is uncertain. Thus, there exist the possibility of natural gas shortage in the future. On the other hand, if all the expected projects will be implemented, situations of oversupply cannot be excluded. A system dynamics model deepens such as issue [it

Sensitivity analysis and its application for dynamic improvement

Indian Academy of Sciences (India)

respect to the design parameter changes such as mass, stiffness or damping addition, one can predict the change ..... Proceedings of the International Winter. School on Optimum Dynamic Design (Delhi: Allied Publishers). Okubo N, Masuda K ...

Proceedings from the conference on the ecology and management of high-elevation forests in the central and southern Appalachian Mountains

Science.gov (United States)

James S. Rentch; Thomas M. Schuler

2010-01-01

The proceedings includes 18 peer-reviewed papers and 41 abstracts pertaining to acid deposition and nutrient cycling, ecological classification, forest dynamics, avifauna, wildlife and fisheries, forests pests, climate change, old-growth forest structure, regeneration, and restoration.

Proceedings of the Ontario Petroleum Institute's 46. annual conference : Ontario oil and gas conference

International Nuclear Information System (INIS)

2007-01-01

This conference provided a forum for industry leaders and researchers to discuss issues related to Ontario's oil and gas industry. Economic profiles of the oil, gas, and salt resource industries were presented along with issues related to underground storage and abandoned oil wells. New technologies designed to improve production efficiency were also presented with particular reference to issues related to climate change and global energy needs. Other topics of discussion included gas storage facilities, the environmental impacts of the oil and gas industry, and issues related to site security. The conference was divided into 5 sessions. Two thesis award papers were also presented along with a keynote address that provided an overview of the petroleum industry's economic outlook. The conference featured 16 presentations, of which 3 have been catalogued separately for inclusion in this database. tabs., figs

Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Properties

Energy Technology Data Exchange (ETDEWEB)

Feltre, Anna [Univ Lyon, Univ Lyon1, Ens de Lyon, Centre National de la Recherche Scientifique, Centre de Recherche Astrophysique de Lyon UMR5574, Saint-Genis-Laval (France); Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Charlot, Stephane [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Mignoli, Marco [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Bongiorno, Angela [INAF-Osservatorio Astronomico di Roma, Monteporzio Catone (Italy); Calura, Francesco [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Chevallard, Jacopo [Scientific Support Office, Directorate of Science and Robotic Exploration, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk (Netherlands); Curtis-Lake, Emma [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Gilli, Roberto [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Plat, Adele, E-mail: anna.feltre@univ-lyon1.fr [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France)

2017-11-02

Spectroscopic studies of active galactic nuclei (AGN) are powerful means of probing the physical properties of the ionized gas within them. In particular, near future observational facilities, such as the James Webb Space Telescope (JWST), will allow detailed statistical studies of rest-frame ultraviolet and optical spectral features of the very distant AGN with unprecedented accuracy. In this proceedings, we discuss the various ways of exploiting new dedicated photoionization models of the narrow-line emitting regions (NLR) of AGN for the interpretation of forthcoming revolutionary datasets.

Selective gas absorption by ionic liquids

DEFF Research Database (Denmark)

Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes

2010-01-01

Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

Monitoring of Greenhouse Gases in the Netherlands: uncertainty and priorities for improvement ; Proceedings of a national workshop held in Bilthoven, 1 September 1999

NARCIS (Netherlands)

Amstel AR van; Olivier JGJ; Ruyssenaars PG; WIMEK; LAE

2004-01-01

A workshop was organised in the Netherlands on 1 September 1999 to improve the National System for Monitoring Greenhouse Gas Emissions. These are the proceedings, including discussion papers, presentations of speakers, reports of discussions and conclusions. It was the task of this workshop to

North American natural gas supply and demand

International Nuclear Information System (INIS)

Goobie, G.

2006-01-01

This presentation was given by leading energy analysts Pervin and Gertz, and provided their outlook on the North American natural gas supply and demand as well as transportation and processing options for the Mackenzie Valley project and the Alaska natural gas project. Arctic gas development was discussed in relation to larger North American and world energy markets. The impacts of liquefied natural gas (LNG) infrastructure development were compared with the potential impacts of the Alaska and Mackenzie Valley pipelines. A review of North American gas supplies was presented. LNG imports to the United States are expected to exceed 8 BCF/D by 2010. In addition, huge growth in the LNG markets is expected in middle eastern countries as well as in Africa. There is currently strong growth in liquefaction capacity in most regions. However, many proposed LNG terminals will not proceed due to opposition on the west coast of North America. It is also expected that natural gas liquids (NGL) delivered to Alberta from the Mackenzie Valley Gas project are expected to be used by the heavy oil industry. Canadian crude supplies are expected to grow to nearly 4 million barrels per day by 2015. The impacts of Alaska and Mackenzie Valley gas projects on western NGL markets and the petrochemicals industry were reviewed. It was concluded that major investments in supply and infrastructure are need in order to develop Arctic gas, as LNG is likely to be the largest source of incremental supply. tabs., figs

Proceedings of the 44. annual Ontario Petroleum Institute's oil and gas conference

International Nuclear Information System (INIS)

2005-01-01

This annual conference focused on developments related to the Ontario Petroleum industry. Issues concerning hydrocarbon potential were examined as well as geological information related to oil and gas activities in the region. The conference was divided into 6 sessions. Session 1 provided updates on employment issues in Ontario's oil and gas industry with respect to regulations and staffing as well as an update of issues concerning the geosciences profession in the province. Session 2 examined approaches to predictive geochemistry for buried gas and oil targets. Session 3 presented a comparison of Cambrian reservoir rocks as well as details of a natural channel realignment project. Session 4 presented details of new renewable technologies for the Ontario petroleum industry as well as a regional stratigraphic synthesis for the Paleozoic of southern Ontario. Session 5 provided a primer on tax rules, workers industry needs and an update on training delivery. Session 6 examined approaches to contaminant control. A study of hydrodynamics at the ice-bed interface was also presented. The conference featured 13 presentations, of which 3 have been catalogued separately for inclusion in this database. refs., tabs., figs

Procedural Justice in Dutch Administrative Court Proceedings

Directory of Open Access Journals (Sweden)

André Verburg

2014-11-01

Full Text Available In this paper we discuss recent developments in administrative court proceedings in the Netherlands, called the New Approach. Along with developments leading to the New Approach, it became clear that the insights from research on procedural justice deserve particular attention. The goals of the judge's actions in this respect are both that the proceedings are fair and just and that parties perceive the way they are being treated during proceedings as fair and just.Within the New Approach we discern five procedural justice elements: (1 respect, (2 voice and due consideration, (3 some influence on how proceedings will continue, (4 an explanation of how the proceedings will continue and (5 direct interpersonal contact.The introduction of the New Approach shows two important bottlenecks in Dutch administrative court proceedings, which are (i the possible or supposed collision between legally right outcomes and  procedural justice and (ii the lack of uniformity and predictability.Although what we describe and discuss in this paper focuses on the Dutch situation, many of these considerations apply to administrative court proceedings in other countries. The themes and difficulties that face the administrative law judge seem to be common to many countries.

Price discovery in European natural gas markets

International Nuclear Information System (INIS)

Schultz, Emma; Swieringa, John

2013-01-01

We provide the first high-frequency investigation of price discovery within the physical and financial layers of Europe's natural gas markets. Testing not only looks at short-term return dynamics, but also considers each security's contribution to price equilibrium in the longer-term. Results show that UK natural gas futures traded on the Intercontinental Exchange display greater price discovery than physical trading at various hubs throughout Europe. - Highlights: • We use intraday data to gauge price discovery in European natural gas markets. • We explore short and long-term dynamics in physical and financial market layers. • Results show ICE's UK natural gas futures are the main venue for price discovery

Nonlinear dynamics aspects of particle accelerators

International Nuclear Information System (INIS)

Jowett, J.M.; Turner, S.; Month, M.

1986-01-01

These proceedings contain the lectures presented at the named winter school. They deal with the application of dynamical systems to accelerator theory. Especially considered are the statistical description of charged-beam plasmas, integrable and nonintegrable Hamiltonian systems, single particle dynamics and nonlinear resonances in circular accelerators, nonlinear dynamics aspects of modern storage rings, nonlinear beam-beam resonances, synchro-betatron resonances, observations of the beam-beam interactions, the dynamics of the beam-beam interactions, beam-beam simulations, the perturbation method in nonlinear dynamics, theories of statistical equilibrium in electron-positron storage rings, nonlinear dissipative phenomena in electron storage rings, the dynamical aperture, the transition to chaos for area-preserving maps, special processors for particle tracking, algorithms for tracking of charged particles in circular accelerators, the breakdown of stability, and a personal perspective of nonlinear dynamics. (HSI)

Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution.

Science.gov (United States)

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-08

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al . 2012 Proc. R. Soc. A 468 , 1799-1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi-Dirac or Bose-Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas.

Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution

Science.gov (United States)

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-01

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799–1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi–Dirac or Bose–Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

Exact dynamics of a one dimensional Bose gas in a periodic time-dependent harmonic trap

Science.gov (United States)

Scopa, Stefano; Unterberger, Jéremie; Karevski, Dragi

2018-05-01

We study the unitary dynamics of a 1D gas of hard-core bosons trapped into a harmonic potential which varies periodically in time with frequency . Such periodic systems can be classified into orbits of different monodromies corresponding to two different physical situations, namely the case in which the bosonic cloud remains stable during the time-evolution and the case where it turns out to be unstable. In the present work we derive in the large particle number limit exact results for the stroboscopic evolution of the energy and particle densities in both physical situations.

Gas dynamics in tidal dwarf galaxies: Disc formation at z = 0

Science.gov (United States)

Lelli, Federico; Duc, Pierre-Alain; Brinks, Elias; Bournaud, Frédéric; McGaugh, Stacy S.; Lisenfeld, Ute; Weilbacher, Peter M.; Boquien, Médéric; Revaz, Yves; Braine, Jonathan; Koribalski, Bärbel S.; Belles, Pierre-Emmanuel

2015-12-01

Tidal dwarf galaxies (TDGs) are recycled objects that form within the collisional debris of interacting and merging galaxies. They are expected to be devoid of non-baryonic dark matter, since they can only form from dissipative material ejected from the discs of the progenitor galaxies. We investigate the gas dynamics in a sample of six bona fide TDGs around three interacting and post-interacting systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace"). For NGC 4694 and NGC 5291, we analyse existing H I data from the Very Large Array (VLA), while for NGC 7252 we present new H I observations from the Jansky VLA, together with long-slit and integral-field optical spectroscopy. For all six TDGs, the H I emission can be described by rotating disc models. These H I discs, however, have undergone less than a full rotation since the time of the interaction/merger event, raising the question of whether they are in dynamical equilibrium. Assuming that these discs are in equilibrium, the inferred dynamical masses are consistent with the observed baryonic masses, implying that TDGs are devoid of dark matter. This puts constraints on putative "dark discs" (either baryonic or non-baryonic) in the progenitor galaxies. Moreover, TDGs seem to systematically deviate from the baryonic Tully-Fisher relation. These results provide a challenging test for alternative theories like MOND. Based on observations made with ESO telescopes at Paranal Observatory under programmes 65.O-0563, 67.B-0049, and 083.B-0647.Appendices are available in electronic form at http://www.aanda.orgThe reduced data cubes are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A113

A model of turbocharger radial turbines appropriate to be used in zero- and one-dimensional gas dynamics codes for internal combustion engines modelling

Energy Technology Data Exchange (ETDEWEB)

Serrano, J.R.; Arnau, F.J.; Dolz, V.; Tiseira, A. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Cervello, C. [Conselleria de Cultura, Educacion y Deporte, Generalitat Valenciana (Spain)

2008-12-15

The paper presents a model of fixed and variable geometry turbines. The aim of this model is to provide an efficient boundary condition to model turbocharged internal combustion engines with zero- and one-dimensional gas dynamic codes. The model is based from its very conception on the measured characteristics of the turbine. Nevertheless, it is capable of extrapolating operating conditions that differ from those included in the turbine maps, since the engines usually work within these zones. The presented model has been implemented in a one-dimensional gas dynamic code and has been used to calculate unsteady operating conditions for several turbines. The results obtained have been compared with success against pressure-time histories measured upstream and downstream of the turbine during on-engine operation. (author)

A model of turbocharger radial turbines appropriate to be used in zero- and one-dimensional gas dynamics codes for internal combustion engines modelling

International Nuclear Information System (INIS)

Serrano, J.R.; Arnau, F.J.; Dolz, V.; Tiseira, A.; Cervello, C.

2008-01-01

The paper presents a model of fixed and variable geometry turbines. The aim of this model is to provide an efficient boundary condition to model turbocharged internal combustion engines with zero- and one-dimensional gas dynamic codes. The model is based from its very conception on the measured characteristics of the turbine. Nevertheless, it is capable of extrapolating operating conditions that differ from those included in the turbine maps, since the engines usually work within these zones. The presented model has been implemented in a one-dimensional gas dynamic code and has been used to calculate unsteady operating conditions for several turbines. The results obtained have been compared with success against pressure-time histories measured upstream and downstream of the turbine during on-engine operation

Hydrodynamics in a Degenerate, Strongly Attractive Fermi Gas

Science.gov (United States)

Thomas, John E.; Kinast, Joseph; Hemmer, Staci; Turlapov, Andrey; O'Hara, Ken; Gehm, Mike; Granade, Stephen

2004-01-01

In summary, we use all-optical methods with evaporative cooling near a Feshbach resonance to produce a strongly interacting degenerate Fermi gas. We observe hydrodynamic behavior in the expansion dynamics. At low temperatures, collisions may not explain the expansion dynamics. We observe hydrodynamics in the trapped gas. Our observations include collisionally-damped excitation spectra at high temperature which were not discussed above. In addition, we observe weakly damped breathing modes at low temperature. The observed temperature dependence of the damping time and hydrodynamic frequency are not consistent with collisional dynamics nor with collisionless mean field interactions. These observations constitute the first evidence for superfluid hydrodynamics in a Fermi gas.

Dynamic simulation and optimization of an industrial-scale absorption tower for CO2 capturing from ethane gas

Directory of Open Access Journals (Sweden)

Babak Pouladi

2016-11-01

Full Text Available This article considers a process technology based on absorption for CO2 capturing of ethane gas in phase 9 and 10 of south pars in Iran using diethanolamine (DEA as absorbent solvent. This CO2 capture plant was designed to achieve 85% CO2 recovery and obtain 19 ppm the CO2 concentration in the outlet of absorber. ASPEN–HYSYS software was used for the dynamic simulation of a commercial-scale CO2 capture plant and amine Pkg equation was chosen from the fluid property package for calculating the thermodynamic properties of the process. A static approach for optimization was used to evaluate the optimum conditions. This research revealed that pressure variation does not have any considerable changes in the absorption process, while both amine inlet temperature and volumetric flow rate increment enhance the absorption tower efficiency. The effect of temperature was very significant as shown in the dynamic study plots. The optimum condition for CO2 absorption from a stream of ethane gas with molar flow rate of 2118 kg mol h−1 was obtained 75 m3  h−1 of amine at 53 °C and 24 bar. This optimized condition is acceptable from economical, safe as well as feasible point of view.

Modelling and dynamic simulation of processes with 'MATLAB'. An application of a natural gas installation in a power plant

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Bustamante, J.A.; Sala, J.M.; Flores, I. [Escuela Superior de Ingenieros Industriales de Bilbao, Universidad del Pais Vasco, Alameda de Urquijo, s/n 48013 Bilbao (Bizkaia) (Spain); Lopez-Gonzalez, L.M. [Escuela Tecnica Superior de Ingenieria Industrial, Universidad de La Rioja, C/ Luis de Ulloa, 20. E 26004 Logrono (La Rioja) (Spain); Miguez, J.L. [Universidad de Vigo, Escuela Tecnica Superior de Ingenieros Industriales, C/Lagoas-Marcosende, s/n 36200 Vigo (Pontevedra) (Spain)

2007-07-15

In this paper, it is proposed to incorporate the analysis of the dynamic performance of the process into the design and engineering stage of projects as a means of analysing and resolving this type of problem. The following contributions are made with this objective in mind:(a)The barriers in the way of dynamic analysis are identified. (b)Software tools which make dynamic analysis accessible during the design and engineering phase of the project are proposed. To achieve this goal, modelling and mathematical simulation are used, with the following features: circle strict modelling of mass, momentum and energy conservation equations as well as state equations, and circle utilisation of the 'Matlab-Simulink' package as the base-software tool. (c)The procedure and tool proposed for dynamic analysis during the design phase should enable these studies to be carried out at a reasonable cost and time for regular industrial projects, and not just for large research projects or nuclear power plants. To complete this paper, we apply our method to a natural gas installation in a power plant. The model is applied to study the transients of a natural gas supply line to a steam-electric power plant. The results of the model have been validated with the actual data on the boiler trip obtained from the distributed control system of a steam-electric power plant. (author)

31st IMAC Conference on Structural Dynamics

CERN Document Server

Adams, Douglas; Carrella, Alex; Mayes, Randy; Rixen, Daniel; Allen, Matt; Cunha, Alvaro; Catbas, Fikret; Pakzad, Shamim; Racic, Vitomir; Pavic, Aleksandar; Reynolds, Paul; Simmermacher, Todd; Cogan, Scott; Moaveni, Babak; Papadimitriou, Costas; Allemang, Randall; Clerck, James; Niezrecki, Christopher; Wicks, Alfred

2013-01-01

Topics in Nonlinear Dynamics, Volume 1: Proceedings of the 31st IMAC, A Conference and Exposition on Structural Dynamics, 2013, the first volume of seven from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on:   Nonlinear Oscillations Nonlinearities In Practice Nonlinear System Identification: Methods Nonlinear System Identification: Friction & Contact Nonlinear Modal Analysis Nonlinear Modeling & Simulation Nonlinear Vibration Absorbers Constructive Utilization of Nonlinearity.

Experimental Research on the Impactive Dynamic Effect of Gas-Pulverized Coal of Coal and Gas Outburst

Directory of Open Access Journals (Sweden)

Haitao Sun

2018-03-01

Full Text Available Coal and gas outburst is one of the major serious natural disasters during underground coal, and the shock air flow produced by outburst has a huge threat on the mine safety. In order to study the two-phase flow of a mixture of pulverized coal and gas of a mixture of pulverized coal and gas migration properties and its shock effect during the process of coal and gas outburst, the coal samples of the outburst coal seam in Yuyang Coal Mine, Chongqing, China were selected as the experimental subjects. By using the self-developed coal and gas outburst simulation test device, we simulated the law of two-phase flow of a mixture of pulverized coal and gas in the roadway network where outburst happened. The results showed that the air in the roadway around the outburst port is disturbed by the shock wave, where the pressure and temperature are abruptly changed. For the initial gas pressure of 0.35 MPa, the air pressure in different locations of the roadway fluctuated and eventually remain stable, and the overpressure of the outburst shock wave was about 20~35 kPa. The overpressure in the main roadway and the distance from the outburst port showed a decreasing trend. The highest value of temperature in the roadway increased by 0.25 °C and the highest value of gas concentration reached 38.12% during the experiment. With the action of shock air flow, the pulverized coal transportation in the roadway could be roughly divided into three stages, which are the accelerated movement stage, decelerated movement stage and the particle settling stage respectively. Total of 180.7 kg pulverized coal of outburst in this experiment were erupted, and most of them were accumulated in the main roadway. Through the analysis of the law of outburst shock wave propagation, a shock wave propagation model considering gas desorption efficiency was established. The relationships of shock wave overpressure and outburst intensity, gas desorption rate, initial gas pressure, cross

Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

International Nuclear Information System (INIS)

Miyabe, M.; Oba, M.; Iimura, H.; Akaoka, K.; Khumaeni, A.; Kato, M.; Wakaida, I.

2015-01-01

The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5–6 J/cm 2 ) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis. - Highlights: • Ablated ground-state species accumulated in a thin hemispherical boundary layer • Inside the layer, a cavity containing a small density of ablated species was formed. • The hemispherical layers of atoms and ions appeared at a nearly identical location. • The measured intensity peak variation was in good agreement with a model prediction. • We ascribed the dominant process for forming the layer to a three-body recombination

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

Hamiltonian aspects of three-wave resonant interactions in gas dynamics

Science.gov (United States)

Webb, G. M.; Zakharian, A.; Brio, M.; Zank, G. P.

1997-06-01

Equations describing three-wave resonant interactions in adiabatic gas dynamics in one Cartesian space dimension derived by Majda and Rosales are expressed in terms of Lagrangian and Hamiltonian variational principles. The equations consist of two coupled integro-differential Burgers equations for the backward and forward sound waves that are coupled by integral terms that describe the resonant reflection of a sound wave off an entropy wave disturbance to produce a reverse sound wave. Similarity solutions and conservation laws for the equations are derived using symmetry group methods for the special case where the entropy disturbance consists of a periodic saw-tooth profile. The solutions are used to illustrate the interplay between the nonlinearity represented by the Burgers self-wave interaction terms and wave dispersion represented by the three-wave resonant interaction terms. Hamiltonian equations in Fourier (p,t) space are also obtained where p is the Fourier space variable corresponding to the fast phase variable 0305-4470/30/12/013/img6 of the waves. The latter equations are transformed to normal form in order to isolate the normal modes of the system.

A range of newly developed mobile generators to dynamically produce SI-traceable reference gas mixtures for reactive compounds at atmospheric concentrations

Science.gov (United States)

Leuenberger, Daiana; Pascale, Céline; Guillevic, Myriam; Ackermann, Andreas; Niederhauser, Bernhard

2017-04-01

Three new mobile facilities have been developed at METAS to dynamically generate SI-traceable reference gas mixtures for a variety of reactive compounds at atmospheric amount of substance fractions and at very low levels of uncertainty (Ux balance. The carrier gas is previously purified from the compounds of interest using commercially available purification cartridges. The permeation chambers of ReGaS2 and ReGaS3 have multiple individual cells allowing for the generation of mixtures containing up to 5 different components if required. ReGaS1 allows for the generation of one-component mixtures only. These primary mixtures are then diluted to the required amount of substance fractions using thermal mass flow controllers for full flexibility and adaptability of the generation process over the entire range of possible concentrations. In order to considerably reduce adsorption/desorption processes and thus stabilisation time, all electro-polished stainless steel parts of ReGaS1 and ReGaS2 in contact with the reference gas mixtures are passivated with SilcoNert2000® surface coating. These three state-of-the-art mobile reference gas generators are applicable under both, laboratory and field conditions. Moreover the dynamic generation method can be adapted and applied to a large variety of molecules (e.g. BTEX, CFCs, HCFCs, HFCs and other refrigerants) and is particularly suitable for reactive gas species and/or at concentration ranges which are unstable when stored in pressurised cylinders. Acknowledgement: This work was supported by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union

Proceedings of the neutrons in biology conference, Santa Fe, NM, October 1994

International Nuclear Information System (INIS)

Schoenborn, B.P.

1994-01-01

This volume provides the proceedings for the Neutrons in Biology Conference held in Sante Fe, New Mexico October 1994. The volume is composed of full papers authored by the presenters at the conference. The sessions by which the presentations were organized are entitled Neutron Anatomy, Neutron Sources, Neutron Instrumentation, Small Angle Scattering, Membrane Structures and Dynamics, Protein Structures, Fiber Diffraction, and New Analysis and Experimental Techniques. Each paper has been separately indexed and abstracted for the database

Proceedings of the neutrons in biology conference, Santa Fe, NM, October 1994

Energy Technology Data Exchange (ETDEWEB)

Schoenborn, B.P.

1994-12-31

This volume provides the proceedings for the Neutrons in Biology Conference held in Sante Fe, New Mexico October 1994. The volume is composed of full papers authored by the presenters at the conference. The sessions by which the presentations were organized are entitled Neutron Anatomy, Neutron Sources, Neutron Instrumentation, Small Angle Scattering, Membrane Structures and Dynamics, Protein Structures, Fiber Diffraction, and New Analysis and Experimental Techniques. Each paper has been separately indexed and abstracted for the database.

Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Properties

Directory of Open Access Journals (Sweden)

Anna Feltre

2017-11-01

Full Text Available Spectroscopic studies of active galactic nuclei (AGN are powerful means of probing the physical properties of the ionized gas within them. In particular, near future observational facilities, such as the James Webb Space Telescope (JWST, will allow detailed statistical studies of rest-frame ultraviolet and optical spectral features of the very distant AGN with unprecedented accuracy. In this proceedings, we discuss the various ways of exploiting new dedicated photoionization models of the narrow-line emitting regions (NLR of AGN for the interpretation of forthcoming revolutionary datasets.

Regression testing Ajax applications : Coping with dynamism

NARCIS (Netherlands)

Roest, D.; Mesbah, A.; Van Deursen, A.

2009-01-01

Note: This paper is a pre-print of: Danny Roest, Ali Mesbah and Arie van Deursen. Regression Testing AJAX Applications: Coping with Dynamism. In Proceedings of the 3rd International Conference on Software Testing, Verification and Validation (ICST’10), Paris, France. IEEE Computer Society, 2010.

Conversion of Coal Mine Gas to LNG

Energy Technology Data Exchange (ETDEWEB)

None, None

2016-02-05

This project evolved from a 1995, DOE-NETL competitive solicitation for practical CMM capture and utilization concepts. Appalachian Pacific was one of three companies selected to proceed with the construction and operation of a cost-shared demonstration plant. In the course of trying to proceed with this demonstration plant, AP examined several liquefaction technologies, discussed obtaining rights to coal mine methane with a number of coal companies, explored marketing potential with a wide variety of customers in many sections of the United States, studied in great detail the impact of a carbon credit exchange, and developed a suite of analytical tools with which to evaluate possible project options. In the end, the newness of the product, reluctance on the part of the coal companies to venture away from time tested practices, difficulty with obtaining financing, the failure of a carbon credit market to develop and the emergence of shale derived gas production prevented a demonstration plant from being built.

An Introduction to the Material Point Method using a Case Study from Gas Dynamics

International Nuclear Information System (INIS)

Tran, L. T.; Kim, J.; Berzins, M.

2008-01-01

The Material Point Method (MPM) developed by Sulsky and colleagues is currently being used to solve many challenging problems involving large deformations and/or fragementations with considerable success as part of the Uintah code created by the CSAFE project. In order to understand the properties of this method an analysis of the considerable computational properties of MPM is undertaken in the context of model problems from gas dynamics. One aspect of the MPM method in the form used here is shown to have first order accuracy. Computational experiments using particle redistribution are described and show that smooth results with first order accuracy may be obtained.

Power to Fuels: Dynamic Modeling of a Slurry Bubble Column Reactor in Lab-Scale for Fischer Tropsch Synthesis under Variable Load of Synthesis Gas

Directory of Open Access Journals (Sweden)

Siavash Seyednejadian

2018-03-01

Full Text Available This research developed a comprehensive computer model for a lab-scale Slurry Bubble Column Reactor (SBCR (0.1 m Dt and 2.5 m height for Fischer–Tropsch (FT synthesis under flexible operation of synthesis gas load flow rates. The variable loads of synthesis gas are set at 3.5, 5, 7.5 m3/h based on laboratory adjustments at three different operating temperatures (483, 493 and 503 K. A set of Partial Differential Equations (PDEs in the form of mass transfer and chemical reaction are successfully coupled to predict the behavior of all the FT components in two phases (gas and liquid over the reactor bed. In the gas phase, a single-bubble-class-diameter (SBCD is adopted and the reduction of superficial gas velocity through the reactor length is incorporated into the model by the overall mass balance. Anderson Schulz Flory distribution is employed for reaction kinetics. The modeling results are in good agreement with experimental data. The results of dynamic modeling show that the steady state condition is attained within 10 min from start-up. Furthermore, they show that step-wise syngas flow rate does not have a detrimental influence on FT product selectivity and the dynamic modeling of the slurry reactor responds quite well to the load change conditions.

6th Stuttgart international symposium on automotive and engine technology. Proceedings; 6. Internationales Stuttgarter Symposium: Kraftfahrwesen und Verbrennungsmotoren. Konferenzband

Energy Technology Data Exchange (ETDEWEB)

Bargende, M.; Reuss, H.C.; Wiedemann, J. (eds.)

2005-07-01

The proceedings volume has three sections: Part 1, 'Engines' discusses diesel engines, engine mechanics, gasoline engines, FVV projects, analysis and simulation. Part 2, 'Vehicles' contains papers on car concepts, dynamics, acoustics and vibrations, aeroacoustics, aerodynamics, thermomanagement and engine cooling. Part 3, 'Motor car mechatronics' goes into board network and energy management, sensors and actuators, dynamics and control, testing and diagnosis, software and design tools, networking and architecture. (orig.)

Proceedings of the Canadian Gas Association's western operations workshop : readiness : reduce the risk

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

The natural gas industry is now facing a number of challenges related to energy infrastructure security and new regulations regarding pipeline and employee safety. Organized by the Canadian Gas Association (CGA), this workshop provided a forum for gas distribution companies, transmission companies, and service providers to discuss issues related to the delivery of natural gas in Canada. While the workshop also included tours and descriptions of specific natural gas facilities and operational centres, several of the breakout sessions during the workshop were used to discuss natural gas technologies and planning procedures related to safety and security. Planning process improvements using risk analysis for operations were discussed. Safety strategies for the 2010 Olympics relating to critical infrastructure protection were reviewed. Issues concerning emergency response preparedness were examined, as well as threats to energy infrastructure from acts of terrorism. Recent innovations in fire retardant clothing were presented. Technological innovations presented at the workshop included a cold weather technology line heater, and new technologies in underground pipe manufacturing. Human resources issues included new approaches to stress management and employee support and safety. The workshop featured 12 breakout sessions, of which 4 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Dynamical vanishing of the order parameter in a confined Bardeen-Cooper-Schrieffer Fermi gas after an interaction quench

Science.gov (United States)

Hannibal, S.; Kettmann, P.; Croitoru, M. D.; Axt, V. M.; Kuhn, T.

2018-01-01

We present a numerical study of the Higgs mode in an ultracold confined Fermi gas after an interaction quench and find a dynamical vanishing of the superfluid order parameter. Our calculations are done within a microscopic density-matrix approach in the Bogoliubov-de Gennes framework which takes the three-dimensional cigar-shaped confinement explicitly into account. In this framework, we study the amplitude mode of the order parameter after interaction quenches starting on the BCS side of the BEC-BCS crossover close to the transition and ending in the BCS regime. We demonstrate the emergence of a dynamically vanishing superfluid order parameter in the spatiotemporal dynamics in a three-dimensional trap. Further, we show that the signal averaged over the whole trap mirrors the spatiotemporal behavior and allows us to systematically study the effects of the system size and aspect ratio on the observed dynamics. Our analysis enables us to connect the confinement-induced modifications of the dynamics to the pairing properties of the system. Finally, we demonstrate that the signature of the Higgs mode is contained in the dynamical signal of the condensate fraction, which, therefore, might provide a new experimental access to the nonadiabatic regime of the Higgs mode.

Simulation Of Gas Focused Liquid Jets

OpenAIRE

Zahoor, Rizwan

2018-01-01

The main aim of dissertation is to develop an experimentally verified computational fluid dynamic (CFD) model of micron-sized liquid jet, produced by an injection molded Gas Dynamic Virtual Nozzle (GDVN). In these nozzles, liquid jets are efficiently orientedly transporting mass and momentum. They are produced by intelligently projecting hydrodynamic focusing effect from a high-speed stream of a co-flowing lower density and lower viscosity gas on a stream of liquid from a feeding capillary. L...

Gas expulsion vs gas retention in young stellar clusters II: effects of cooling and mass segregation

Science.gov (United States)

Silich, Sergiy; Tenorio-Tagle, Guillermo

2018-05-01

Gas expulsion or gas retention is a central issue in most of the models for multiple stellar populations and light element anti-correlations in globular clusters. The success of the residual matter expulsion or its retention within young stellar clusters has also a fundamental importance in order to understand how star formation proceeds in present-day and ancient star-forming galaxies and if proto-globular clusters with multiple stellar populations are formed in the present epoch. It is usually suggested that either the residual gas is rapidly ejected from star-forming clouds by stellar winds and supernova explosions, or that the enrichment of the residual gas and the formation of the second stellar generation occur so rapidly, that the negative stellar feedback is not significant. Here we continue our study of the early development of star clusters in the extreme environments and discuss the restrictions that strong radiative cooling and stellar mass segregation provide on the gas expulsion from dense star-forming clouds. A large range of physical initial conditions in star-forming clouds which include the star-forming cloud mass, compactness, gas metallicity, star formation efficiency and effects of massive stars segregation are discussed. It is shown that in sufficiently massive and compact clusters hot shocked winds around individual massive stars may cool before merging with their neighbors. This dramatically reduces the negative stellar feedback, prevents the development of the global star cluster wind and expulsion of the residual and the processed matter into the ambient interstellar medium. The critical lines which separate the gas expulsion and the gas retention regimes are obtained.

Thermal-Flow Code for Modeling Gas Dynamics and Heat Transfer in Space Shuttle Solid Rocket Motor Joints

Science.gov (United States)

Wang, Qunzhen; Mathias, Edward C.; Heman, Joe R.; Smith, Cory W.

2000-01-01

A new, thermal-flow simulation code, called SFLOW. has been developed to model the gas dynamics, heat transfer, as well as O-ring and flow path erosion inside the space shuttle solid rocket motor joints by combining SINDA/Glo, a commercial thermal analyzer. and SHARPO, a general-purpose CFD code developed at Thiokol Propulsion. SHARP was modified so that friction, heat transfer, mass addition, as well as minor losses in one-dimensional flow can be taken into account. The pressure, temperature and velocity of the combustion gas in the leak paths are calculated in SHARP by solving the time-dependent Navier-Stokes equations while the heat conduction in the solid is modeled by SINDA/G. The two codes are coupled by the heat flux at the solid-gas interface. A few test cases are presented and the results from SFLOW agree very well with the exact solutions or experimental data. These cases include Fanno flow where friction is important, Rayleigh flow where heat transfer between gas and solid is important, flow with mass addition due to the erosion of the solid wall, a transient volume venting process, as well as some transient one-dimensional flows with analytical solutions. In addition, SFLOW is applied to model the RSRM nozzle joint 4 subscale hot-flow tests and the predicted pressures, temperatures (both gas and solid), and O-ring erosions agree well with the experimental data. It was also found that the heat transfer between gas and solid has a major effect on the pressures and temperatures of the fill bottles in the RSRM nozzle joint 4 configuration No. 8 test.

Offshore Newfoundland: from a project to an industry. Conference '95 proceedings

International Nuclear Information System (INIS)

Keough, S.

1995-01-01

The Proceedings of the 11. International Offshore Petroleum Conference consists of 18 papers, organized into four sessions, dealing, respectively, with (1) Hibernia today, (2) downstream operations, (3) future developments, and (4) international marketing and competitiveness. The majority of the papers dealt with the Hibernia project off the coast of Newfoundland. An update of the project to date, planning for the start-up of production, lifting and transportation problems, plans for the Come By Chance refinery, future developments, marketing Newfoundland's offshore expertise internationally, and perspectives on the international oil and gas industry were the principal issues discussed. A list of conference participants was also included. Figs., tabs

Proceedings of the workshops on the utilization of electron beams

International Nuclear Information System (INIS)

Sato, Shoichi

1993-09-01

Workshops organized by JAERI in cooperation with OAEP, BATAN and JAIF on the utilization of electron beam (EB) were held in Bangkok and Jakarta on 9 and 13 July 1992, respectively. The proceedings contain 13 papers presented at the Workshops. Welcome remarks, opening address and closing remarks are also recorded. At the first part of the Workshops, general view on the application of electron accelerators and introduction of electron accelerators were made. Potential applications of electron accelerators to polymer processing, sterilization of medical products, flue gas purification, treatment of wastewater and sewage sludge and bioresources were introduced from Japanese participants. Potential application of electron accelerators to polymer processing and food irradiation in Thailand and Indonesia were also discussed. (author)

Western Pacific liquefied natural gas