Electron capture in slow collisions of multicharged ions with hydrogen atoms using merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1991-01-01

Absolute total electron-capture cross-section mesurements are reported for collisions of O 3+ and O 4+ with atomic hydrogen in the energy range 1-1000 eV /amu using merged beams. The data are compared with available coupled-states theoretical calculations. (orig.)

Low-energy charge transfer for collisions of Si3+ with atomic hydrogen

Science.gov (United States)

Bruhns, H.; Kreckel, H.; Savin, D. W.; Seely, D. G.; Havener, C. C.

2008-06-01

Cross sections of charge transfer for Si3+ ions with atomic hydrogen at collision energies of ≈40-2500eV/u were carried out using a merged-beam technique at the Multicharged Ion Research Facility at Oak Ridge National Laboratory. The data span an energy range in which both molecular orbital close coupling (MOCC) and classical trajectory Monte Carlo (CTMC) calculations are available. The influence of quantum mechanical effects of the ionic core as predicted by MOCC is clearly seen in our results. However, discrepancies between our experiment and MOCC results toward higher collision energies are observed. At energies above 1000 eV/u good agreement is found with CTMC results.

Resonance charge exchange between excited states in slow proton-hydrogen collisions

International Nuclear Information System (INIS)

Tolstikhina, Inga Yu.; Kato, Daiji

2010-01-01

The theory of resonance charge exchange in slow collisions of a proton with a hydrogen atom in the excited state is developed. It extends the Firsov-Demkov theory of resonance charge exchange to the case of degenerate initial and final states. The theory is illustrated by semiclassical and quantum calculations of charge exchange cross sections between states with n=2 in parabolic and spherical coordinates. The results are compared with existing close-coupling calculations.

Progress in hydrogen fueled busses

International Nuclear Information System (INIS)

Scott, P.B.; Mazaika, D.M.; Tyler, T.

2004-01-01

'Full text:' The Thor/ISE fuel cell bus has been in demonstration and revenue service during 2002-2003 at sites including SunLine Transit, Chula Vista Transit, Los Angeles County Metropolitan Transit Authority, and AC Transit in Oakland. By taking advantage of ISE's advanced hybrid-electric drive technology, this 30-foot bus operates with a much smaller fuel cell than those used in other buses of this class. Further, stress on the fuel cell is diminished. Based on the exceptional performance of this prototype bus, the transit agencies listed above have concluded that hybrid electric hydrogen fueled buses are attractive. Two types of hydrogen fueled hybrid electric buses will be described: - fuel cell powered, and - HICE (Hydrogen Internal Combustion Engine) This progress report will include: 1. Experience with the Thor/ISE fuel cell bus, including results from revenue service at two transit locations, 2. Design and fabrication status of the advanced fuel cell buses being built for AC Transit and SunLine Transit, 3. Design and fabrication status of the prototype HHICE (Hybrid electric Hydrogen fueled Internal Combustion Engine) bus that uses a Ford hydrogen burning engine, mated to a generator, rather than a fuel cell. Other than the engine, the drive train in the HHICE bus is nearly identical to that of a fuel cell hybrid-electric bus. Canadian participation in the HHICE bus is extensive, it is a New Flyer platform and will be winter tested in Winnipeg. (author)

Progress of Nuclear Hydrogen Program in Korea

International Nuclear Information System (INIS)

Lee, Won Jae

2009-01-01

To cope with dwindling fossil fuels and climate change, it is clear that a clean alternative energy that can replace fossil fuels is required. Hydrogen is considered a promising future energy solution because it is clean, abundant and storable and has a high energy density. As other advanced countries, the Korean government had established a long-term vision for transition to the hydrogen economy in 2005. One of the major challenges in establishing a hydrogen economy is how to produce massive quantities of hydrogen in a clean, safe and economical way. Among various hydrogen production methods, the massive, safe and economic production of hydrogen by water splitting using a very high temperature gas-cooled reactor (VHTR) can provide a success path to the hydrogen economy. Particularly in Korea, where usable land is limited, the nuclear production of hydrogen is deemed a practical solution due to its high energy density. To meet the expected demand for hydrogen, the Korea Atomic Energy Institute (KAERI) launched a nuclear hydrogen program in 2004 together with Korea Institute of Energy Research (KIER) and Korea Institute of Science and Technology (KIST). Then, the nuclear hydrogen key technologies development program was launched in 2006, which aims at the development and validation of key and challenging technologies required for the realization of the nuclear hydrogen production demonstration system. In 2008, Korean Atomic Energy Commission officially approved a long-term development plan of the nuclear hydrogen system technologies as in the figure below and now the nuclear hydrogen program became the national agenda. This presentation introduces the current status of nuclear hydrogen projects in Korea and the progress of the nuclear hydrogen key technologies development. Perspectives of nuclear process heat applications are also addressed

Muonium/muonic hydrogen formation in atomic hydrogen

Indian Academy of Sciences (India)

The muonium/muonic hydrogen atom formation in ± –H collisions is investigated, using a two-state approximation in a time dependent formalism. It is found that muonium cross-section results are similar to the cross-section results obtained for positronium formation in + –H collision. Muonic hydrogen atom formation ...

Electron capture in collisions of S4+ with atomic hydrogen

Science.gov (United States)

Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

2001-06-01

Charge transfer processes due to collisions of ground state S4+(3s2 1S) ions with atomic hydrogen are investigated for energies between 1 meV u-1 and 10 MeV u-1 using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S3+ excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 106 K are also presented.

FY 2005 Annual Progress Report for the DOE Hydrogen Program

Energy Technology Data Exchange (ETDEWEB)

None

2005-10-01

In cooperation with industry, academia, national laboratories, and other government agencies, the Department of Energy's Hydrogen Program is advancing the state of hydrogen and fuel cell technologies in support of the President's Hydrogen Fuel Initiative. The initiative seeks to develop hydrogen, fuel cell, and infrastructure technologies needed to make it practical and cost-effective for Americans to choose to use fuel cell vehicles by 2020. Significant progress was made in fiscal year 2005 toward that goal.

Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron

Science.gov (United States)

Barklem, P. S.

2018-05-01

Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multi-channel Landau-Zener model. An extensive calculation including 166 covalent states and 25 ionic states is presented and rate coefficients are calculated for temperatures in the range 1000-20 000 K. The largest rates are found for charge transfer processes to and from two clusters of states around 6.3 and 6.6 eV excitation, corresponding in both cases to active 4d and 5p electrons undergoing transfer. Excitation and de-excitation processes among these two sets of states are also significant. Full Tables and rate coefficient data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A90

Negative ion collisions. Progress report, April 1, 1994 - March 31, 1997

International Nuclear Information System (INIS)

Champion, R.L.

1996-08-01

During the last three years, the experimental activities have concentrated on several somewhat distinct projects. First, the author has measured total cross sections for electron detachment and charge transfer for collisions of various negative ions with atomic hydrogen and the molecular target, O 3 (ozone). The second type of gas phase experiments investigated the collisional decomposition of the molecular ion H 3 + . Specifically he has measured total cross sections for dissociation and proton transfer with an apparatus utilizing a static gas target cell. The targets include hydrogen, deuterium and the rare gases. He has extended these experiments to include D 3 + in a crossed beam configuration in order to provide a more detailed understanding of the collisional dynamics for these reactants. In the area of ion-surface collisions he has measured sputtering yields for O - and electrons arising from collisions of ions with an Al/O surface. The amount of oxygen on the surface is carefully controlled and the kinetic energy distributions of the ejected anions and electrons have been determined. He has been able to develop a theoretical model which, to a large degree, can describe the process. In a slightly speculative endeavor, he has begun investigating the role of atom-catalyzed field emission, i.e., the extent to which an unoccupied negative ion state for an atom near a surface--under the influence of a strong electric field--can serve as a stepping-stone for electron field emission. Very brief accounts of these activities will be given in this report in section 2. Detailed discussions of the experimental results and their analyses published during the contract period may be found in the following articles which have appeared in the archival literature. Copies of these publications are appended to this report as section 4

2010 Annual Progress Report: DOE Hydrogen Program

Energy Technology Data Exchange (ETDEWEB)

2011-02-01

In the past year, the DOE Hydrogen Program (the Program) made substantial progress toward its goals and objectives. The Program has conducted comprehensive and focused efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. With emphasis on applications that will effectively strengthen our nation's energy security and improve our stewardship of the environment, the Program engages in research, development, and demonstration of critical improvements in the technologies. Highlights of the Program's accomplishments can be found in the sub-program chapters of this report.

Measurements of scattering processes in negative ion: Atom collisions. Technical progress report, 1 September 1991--31 December 1994

International Nuclear Information System (INIS)

Kvale, T.J.

1994-01-01

This report describes the progress made on the research objectives during the past three years of the grant. This research project is designed to study various scattering processes which occur in H - collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H - is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements will provide total cross sections (TCS) initially, and once the angular positioning apparatus is installed, will provide angular differential cross sections (ADCS)

Low Energy Charge Transfer for Collisions of Si³⁺ with Atomic Hydrogen

Energy Technology Data Exchange (ETDEWEB)

Bruhns, H. [Columbia University; Kreckel, H. [Columbia University; Savin, D. W. [Columbia University; Seely, D. G. [Albion College; Havener, Charles C [ORNL

2008-01-01

Cross sections of charge transfer for Si{sup 3+} ions with atomic hydrogen at collision energies of {approx} 40-2500 eV/u were carried out using a merged-beam technique at the Multicharged Ion Research Facility at Oak Ridge National Laboratory. The data span an energy range in which both molecular orbital close coupling (MOCC) and classical trajectory Monte Carlo (CTMC) calculations are available. The influence of quantum mechanical effects of the ionic core as predicted by MOCC is clearly seen in our results. However, discrepancies between our experiment and MOCC results toward higher collision energies are observed. At energies above 1000 eV/u good agreement is found with CTMC results.

Measurements of scattering processes in negative ion-atom collisions

International Nuclear Information System (INIS)

Kvale, T.J.

1992-01-01

This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H - collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H - is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991

Excited-state positronium formation from positron--atomic-hydrogen collisions

International Nuclear Information System (INIS)

Mandal, C.R.; Mandal, M.; Mukherjee, S.C.

1991-01-01

Positronium formation into ground and n=2 levels has been studied in collisions of positrons with atomic hydrogen in the framework of an approximation called the boundary-corrected continuum-intermediate-state (BCCIS) approximation in the energy range of 0.08--2 keV. The conventional continuum-intermediate-state approximation does not satisfy the correct boundary condition. It has been shown that, with a suitable choice of the distorting potential, the boundary condition may be satisfied with a proper account of the intermediate continuum states. It has also been shown that the BCCIS approximation leads to the same transition amplitude as may be derived using the Vainshtein-Presnyakov-Sobelman approximation. The results obtained here are found to be in good agreement when compared with other theoretical results

Excitation and charge transfer in low-energy hydrogen atom collisions with neutral oxygen

Science.gov (United States)

Barklem, P. S.

2018-02-01

Excitation and charge transfer in low-energy O+H collisions is studied; it is a problem of importance for modelling stellar spectra and obtaining accurate oxygen abundances in late-type stars including the Sun. The collisions have been studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multichannel Landau-Zener model. The method has been extended to include configurations involving excited states of hydrogen using an estimate for the two-electron transition coupling, but this extension was found to not lead to any remarkably high rates. Rate coefficients are calculated for temperatures in the range 1000-20 000 K, and charge transfer and (de)excitation processes involving the first excited S-states, 4s.5So and 4s.3So, are found to have the highest rates. Data are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/vizbin/qcat?J/A+A/610/A57. The data are also available at http://https://github.com/barklem/public-data

Charge exchange of excited mesic atoms of hydrogen isotopes in triple collisions with molecules

International Nuclear Information System (INIS)

Men'shikov, L.I.; Ponomarev, L.I.

1985-01-01

At high densities of deuterium-tritium mixture the probability for the occurrence of the isotope-exchange reaction (dμ)/sub n/+t → d+(tμ)/sub n/ from the excited states of n mesic atoms of deuterium is high in the triple collisions of mesic atoms with the molecules of hydrogen isotopes. This reaction should be taken into account in describing the kinetics of muon catalysis

Electron capture in collisions of S{sup 4+} with atomic hydrogen

Energy Technology Data Exchange (ETDEWEB)

Stancil, P.C. [Department of Physics and Astronomy, University of Georgia, Athens, GA (United States)]. E-mail: stancil@physast.uga.edu; Turner, A.R. [Department of Chemistry, University of Liverpool, Liverpool (United Kingdom)]. E-mail: art@liv.ac.uk; Cooper, D.L. [Department of Chemistry, University of Liverpool, Liverpool (United Kingdom)]. E-mail: dlc@liv.ac.uk; Schultz, D.R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mail: schultz@mail.phy.ornl.gov; Rakovic, M.J. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mail: milun@mail.phy.ornl.gov; Fritsch, W. [Abteilung Theoretische Physik, Hahn-Meitner-Institut Berlin, Berlin (Germany)]. E-mail: fritsch@hmi.de; Zygelman, B. [Department of Physics, University of Nevada, Las Vegas, NV (United States)]. E-mail: bernard@physics.unlv.edu

2001-06-28

Charge transfer processes due to collisions of ground state S{sup 4+}(3s{sup 2} {sup 1}S) ions with atomic hydrogen are investigated for energies between 1 meV u{sup -1} and 10 MeV u{sup -1} using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S{sup 3+} excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 10{sup 6} K are also presented. (author)

Muon transfer rates in collisions of hydrogen isotope mesic atoms on 'bare' nuclei. Multichannel adiabatic approach

International Nuclear Information System (INIS)

Korobov, V.I.; Melezhik, V.S.; Ponomarev, L.I.

1992-01-01

A numerical scheme for solving the problem of slow collisions in the three-body adiabatic approach is applied for calculation of muon transfer rates in collisions of hydrogen isotope atoms on bare nuclei. It is demonstrated that the multichannel adiabatic approach allows one to reach high accuracy results (∼3%) estimating the cross sections of charge transfer processes which are the best ones up to date. The method is appliable in a wide range of energies (0.001-50 eV) which is of interest for analysis of muon catalysed fusion experiments. 20 refs.; 3 figs.; 5 tabs

Correlated charge-changing ion-atom collisions. Progress report, 16 February 1993--15 April 1994

International Nuclear Information System (INIS)

Tanis, J.A.

1994-04-01

This report summarizes the progress and accomplishments of research supported by DOE. This work involves the experimental investigation of fundamental atomic processes in collisions of few-electron, charged projectile ions with neutral gas targets or electrons. The major emphasis is the study of collision processes involving two active electrons, and particularly those in which the electron-electron interaction plays a role. New results have been obtained for studies involving (1) continuum-electron emission, (2) double ionization of helium and Li + , and (3) resonant recombination of atomic ions. Experiments were conducted using accelerators at Western Michigan University, Michigan State University, Indiana University, Lawrence Livermore Laboratory, and the Institute of Nuclear Research, Debrecen, Hungary. Brief summaries of work completed and work in progress are given

Free hydrogen atom collision cross sections of interest in controlled thermonuclear research

Energy Technology Data Exchange (ETDEWEB)

Fite, W L [John Jay Hopkins Laboratory for Pure and Applied Science, General Atomic Division of General Dynamics Corporation, San Diego, CA (United States)

1958-07-01

The present paper summarizes the results of measurements of the cross sections of hydrogen atoms for: (1) ionization, (2) excitation of Lyman alpha radiation on electron impact, and (3) elastic scattering of electrons of energy less than 10 eV; and also describes the approach of measurements now in progress on (4) charge-exchange between deuterons and deuterium atoms and (5) ionization of the hydrogen atom on proton impact.

Collision processes of highly excited hydrogen atom, 1

International Nuclear Information System (INIS)

Toshima, Nobuyuki

1977-01-01

The cross sections for the transitions 5S sub(1/2) → 5P sub(1/2), 5S sub(1/2) → 5P sub(3/2), 5P sub(1/2) → 5D sub(3/2), 5S sub(1/2) → 5D sub(3/2) and 5S sub(1/2) → 5D sub(5/2) in the hydrogen atom by proton impact are calculated on the basis of the impact parameter method. Distant collisions are dominant and the couplings among the sub-levels belonging to the same n are important at low energies, but the couplings with the levels belonging to different n's are negligibly small. The Glauber and the Born approximations are also applied to the same problem and the Glauber approximation gives a good agreement with the impact parameter method over a wide energy range down to at least about 100 eV. (auth.)

Data on inelastic processes in low-energy potassium-hydrogen and rubidium-hydrogen collisions

Science.gov (United States)

Yakovleva, S. A.; Barklem, P. S.; Belyaev, A. K.

2018-01-01

Two sets of rate coefficients for low-energy inelastic potassium-hydrogen and rubidium-hydrogen collisions were computed for each collisional system based on two model electronic structure calculations, performed by the quantum asymptotic semi-empirical and the quantum asymptotic linear combinations of atomic orbitals (LCAO) approaches, followed by quantum multichannel calculations for the non-adiabatic nuclear dynamics. The rate coefficients for the charge transfer (mutual neutralization, ion-pair formation), excitation and de-excitation processes are calculated for all transitions between the five lowest lying covalent states and the ionic states for each collisional system for the temperature range 1000-10 000 K. The processes involving higher lying states have extremely low rate coefficients and, hence, are neglected. The two model calculations both single out the same partial processes as having large and moderate rate coefficients. The largest rate coefficients correspond to the mutual neutralization processes into the K(5s 2S) and Rb(4d 2D) final states and at temperature 6000 K have values exceeding 3 × 10-8 cm3 s-1 and 4 × 10-8 cm3 s-1, respectively. It is shown that both the semi-empirical and the LCAO approaches perform equally well on average and that both sets of atomic data have roughly the same accuracy. The processes with large and moderate rate coefficients are likely to be important for non-LTE modelling in atmospheres of F, G and K-stars, especially metal-poor stars.

Design progress of cryogenic hydrogen system for China Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R. (China)

2014-01-29

China Spallation Neutron Source (CSNS) is a large proton accelerator research facility with 100 kW beam power. Construction started in October 2011 and is expected to last 6.5 years. The cryogenic hydrogen circulation is cooled by a helium refrigerator with cooling capacity of 2200 W at 20 K and provides supercritical hydrogen to neutron moderating system. Important progresses of CSNS cryogenic system were concluded as follows. Firstly, process design of cryogenic system has been completed including helium refrigerator, hydrogen loop, gas distribution, and safety interlock. Secondly, an accumulator prototype was designed to mitigate pressure fluctuation caused by dynamic heat load from neutron moderation. Performance test of the accumulator has been carried out at room and liquid nitrogen temperature. Results show the accumulator with welding bellows regulates hydrogen pressure well. Parameters of key equipment have been identified. The contract for the helium refrigerator has been signed. Mechanical design of the hydrogen cold box has been completed, and the hydrogen pump, ortho-para hydrogen convertor, helium-hydrogen heat exchanger, hydrogen heater, and cryogenic valves are in procurement. Finally, Hydrogen safety interlock has been finished as well, including the logic of gas distribution, vacuum, hydrogen leakage and ventilation. Generally, design and construction of CSNS cryogenic system is conducted as expected.

Strong isotope effects on the charge transfer in slow collisions of He2+ with atomic hydrogen, deuterium, and tritium

NARCIS (Netherlands)

Stolterfoht, N.; Cabrera-Trujillo, R.; Oehrn, Y.; Deumens, E.; Hoekstra, R.; Sabin, J. R.

2007-01-01

Probabilities and cross sections for charge transfer by He2+ impact on atomic hydrogen (H), deuterium (D), and tritium (T) at low collision energies are calculated. The results are obtained using an ab initio theory, which solves the time-dependent Schrodinger equation. For the H target, excellent

Calculation of the positronium formation differential cross section for collision of electron with anti-hydrogen atoms

International Nuclear Information System (INIS)

Ghanbari Adivi, E.; Kanjuri, F.; Bolorizadeh, M.

2006-01-01

The positronium formation differential cross sections in collision of the high-energy but non-relativistic electrons with anti-hydrogen atoms are calculated by using the three-body Faddeev-Watson-Lovelace formalism. In a second-order approximation, the inter-nuclear and nuclear-electronic partial amplitudes therein the Faddeev-Watson series are calculated, analytically, in the range of 0-180 degrees of the scattering angles. The presence of the T homas peak a t 45 d egree i s investigated. The results are discussed for 1 and 10 keV impact energies and for electron transition from anti-hydrogen ground state into the different states therein the K-, L- and M- shells of the positronium atoms.

Ab initio study of charge transfer in B2+ low-energy collisions with atomic hydrogen

International Nuclear Information System (INIS)

Turner, A.R.; Cooper, D.L.; Wang, J.G.; Stancil, P.C.

2003-01-01

Charge transfer processes due to collisions of ground state B 2+ (2s 2 S) ions with atomic hydrogen are investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) method. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial and rotational coupling matrix elements obtained with the spin-coupled valence-bond approach. Total and state-selective cross sections and rate coefficients are presented. Comparison with the existing experiments shows our results to be in good agreement. When E 400 eV/u, inclusion of rotational coupling increases the total cross section by 50%-80%, improving the agreement between the current calculations and experiments. For state-selective cross sections, rotational coupling induces mixing between different symmetries; however, its effect, especially at low collision energies, is not as important as had been suggested in previous work

2016 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

Energy Technology Data Exchange (ETDEWEB)

Satyapal, Sunita [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-02-01

In the past year, the DOE Hydrogen Program (the Program) made substantial progress toward its goals and objectives. The Program has conducted comprehensive and focused efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. With emphasis on applications that will effectively strengthen our nation's energy security and improve our stewardship of the environment, the Program engages in research, development, and demonstration of critical improvements in the technologies. Highlights of the Program's accomplishments can be found in the sub-program chapters of this report.

2015 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

Energy Technology Data Exchange (ETDEWEB)

Popovich, Neil

2015-12-01

In the past year, the DOE Hydrogen Program (the Program) made substantial progress toward its goals and objectives. The Program has conducted comprehensive and focused efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. With emphasis on applications that will effectively strengthen our nation's energy security and improve our stewardship of the environment, the Program engages in research, development, and demonstration of critical improvements in the technologies. Highlights of the Program's accomplishments can be found in the sub-program chapters of this report.

2012 Annual Progress Report: DOE Hydrogen and Fuel Cells Program

Energy Technology Data Exchange (ETDEWEB)

2012-12-01

In the past year, the DOE Hydrogen Program (the Program) made substantial progress toward its goals and objectives. The Program has conducted comprehensive and focused efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. With emphasis on applications that will effectively strengthen our nation's energy security and improve our stewardship of the environment, the Program engages in research, development, and demonstration of critical improvements in the technologies. Highlights of the Program's accomplishments can be found in the sub-program chapters of this report.

Ab initio study of charge transfer in B2+ low-energy collisions with atomic hydrogen

Science.gov (United States)

Turner, A. R.; Cooper, D. L.; Wang, J. G.; Stancil, P. C.

2003-07-01

Charge transfer processes due to collisions of ground state B2+(2s 2S) ions with atomic hydrogen are investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) method. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial and rotational coupling matrix elements obtained with the spin-coupled valence-bond approach. Total and state-selective cross sections and rate coefficients are presented. Comparison with the existing experiments shows our results to be in good agreement. When EMOCC cross sections with and without rotational coupling are small (400 eV/u, inclusion of rotational coupling increases the total cross section by 50% 80%, improving the agreement between the current calculations and experiments. For state-selective cross sections, rotational coupling induces mixing between different symmetries; however, its effect, especially at low collision energies, is not as important as had been suggested in previous work.

Beneficial effects of hydrogen-rich saline on early burn-wound progression in rats.

Directory of Open Access Journals (Sweden)

Song Xue Guo

Full Text Available Deep burn wounds undergo a dynamic process known as wound progression that results in a deepening and extension of the initial burn area. The zone of stasis is more likely to develop more severe during wound progression in the presence of hypoperfusion. Hydrogen has been reported to alleviate injury triggered by ischaemia/reperfusion and burns in various organs by selectively quenching oxygen free radicals. The aim of this study was to investigate the possible protective effects of hydrogen against early burn-wound progression.Deep-burn models were established through contact with a boiled, rectangular, brass comb for 20 s. Fifty-six Sprague-Dawley rats were randomly divided into sham, burn plus saline, and burn plus hydrogen-rich saline (HS groups with sacrifice and analysis at various time windows (6 h, 24 h, 48 h post burn. Indexes of oxidative stress, apoptosis and autophagy were measured in each group. The zone of stasis was evaluated using immunofluorescence staining, ELISA, and Western blot to explore the underlying effects and mechanisms post burn.The burn-induced increase in malondialdehyde was markedly reduced with HS, while the activities of endogenous antioxidant enzymes were significantly increased. Moreover, HS treatment attenuated increases in apoptosis and autophagy postburn in wounds, according to the TUNEL staining results and the expression analysis of Bax, Bcl-2, caspase-3, Beclin-1 and Atg-5 proteins. Additionally, HS lowered the level of myeloperoxidase and expression of TNF-α, IL-1β, and IL-6 in the zone of stasis while augmenting IL-10. The elevated levels of Akt phosphorylation and NF-κB p65 expression post burn were also downregulated by HS management.Hydrogen can attenuate early wound progression following deep burn injury. The beneficial effect of hydrogen was mediated by attenuating oxidative stress, which inhibited apoptosis and inflammation, and the Akt/NF-κB signalling pathway may be involved in regulating the

Experimental investigation of the formation of negative hydrogen ions in collisions between positive ions and atomic or molecular targets

International Nuclear Information System (INIS)

Lattouf, Elie

2013-01-01

The formation of the negative hydrogen ion (H - ) in collisions between a positive ion and a neutral atomic or molecular target is studied experimentally at impact energies of a few keV. The doubly-differential cross sections for H - formation are measured as a function of the kinetic energy and emission angle for the collision systems OH + + Ar and O + + H 2 O at 412 eV/a.m.u. These H - ions can be emitted at high energies (keV) in hard quasi-elastic two-body collisions involving a large momentum transfer to the H center. However, H - anions are preferentially emitted at low energy (eV) due to soft many-body (≥ 2) collisions resulting in a low momentum transfer. The formation of H - ions by electron capture follows excitation or ionization of the molecule. The molecular fragmentation dynamics is modeled to simulate the emission of H - ions. The overall good agreement between the simulation and the experiment leads to the understanding of most of the experimental observations. (author) [fr

Hydrogen Atom Collision Processes in Cool Stellar Atmospheres: Effects on Spectral Line Strengths and Measured Chemical Abundances in Old Stars

International Nuclear Information System (INIS)

Barklem, Paul S

2012-01-01

The precise measurement of the chemical composition of stars is a fundamental problem relevant to many areas of astrophysics. State-of-the-art approaches attempt to unite accurate descriptions of microphysics, non-local thermodynamic equilibrium (non-LTE) line formation and 3D hydrodynamical model atmospheres. In this paper I review progress in understanding inelastic collisions of hydrogen atoms with other species and their influence on spectral line formation and derived abundances in stellar atmospheres. These collisions are a major source of uncertainty in non-LTE modelling of spectral lines and abundance determinations, especially for old, metal-poor stars, which are unique tracers of the early evolution of our galaxy. Full quantum scattering calculations of direct excitation processes X(nl) + H ↔ X(n'l') + H and charge transfer processes X(nl) + H ↔ X + + H − have been done for Li, Na and Mg [1,2,3] based on detailed quantum chemical data, e.g. [4]. Rate coefficients have been calculated and applied to non-LTE modelling of spectral lines in stellar atmospheres [5,6,7,8,9]. In all cases we find that charge transfer processes from the first excited S-state are very important, and the processes affect measured abundances for Li, Na and Mg in some stars by as much as 60%. Effects vary with stellar parameters (e.g. temperature, luminosity, metal content) and so these processes are important not only for accurate absolute abundances, but also for relative abundances among dissimilar stars.

Collision-Induced Infrared Absorption by Hydrogen-Helium gas mixtures at Thousands of Kelvin

Science.gov (United States)

Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

2010-10-01

The interaction-induced absorption by collisional pairs of H2 molecules is an important opacity source in the atmospheres of the outer planets and cool stars ^[1]. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H2--H2, H2--He, and H2--H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin ^[2]. Laboratory measurements of interaction-induced absorption spectra by H2 pairs exist only at room temperature and below. We show that our results reproduce these measurements closely ^[2], so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures ^[2]. [1] L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 [2] Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, ``Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin'', International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201

2011 Annual Progress Report: DOE Hydrogen and Fuel Cells Program (Book)

Energy Technology Data Exchange (ETDEWEB)

2011-11-01

In the past year, the DOE Hydrogen and Fuel Cells Program (the Program) made substantial progress toward its goals and objectives. The Program has conducted comprehensive and focused efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. With emphasis on applications that will effectively strengthen our nation's energy security and improve our stewardship of the environment, the Program engages in research, development, and demonstration of critical improvements in the technologies. Highlights of the Program's accomplishments can be found in the sub-program chapters of this report.

Dynamics of the water dimer + nitric oxide collision

Energy Technology Data Exchange (ETDEWEB)

Ree, Jong Baik [Dept. of Chemistry Education, Chonnam National University, Gwangju (Korea, Republic of); Kim, Yoo Hang [Dept. of Chemistry, Inha University, Incheon (Korea, Republic of); Shin, Hyung Kyu [Dept. of Chemistry, University of Nevada, Nevada (Korea, Republic of)

2017-02-15

Collision-induced intermolecular energy transfer and intramolecular vibrational redistribution in the collision of a water dimer and nitric oxide are studied by use of quasiclassical procedures. Intermolecular energy flow is shown to occur mainly through a direct-mode mechanism transferring relatively large amounts in strong collisions. About a quarter of the energy initially deposited in the dimer transfers to the ground state NO, while the rest redistributes among internal motions of the collision system. The main portion of initial energy deposited in the dimer redistributes in the stretches of the donor monomer through the 1:1 resonance followed by in the bend through the 1:2 resonance. Energy transfer from the excited NO to the ground-state dimer is equally efficient, transferring more than half the initial excitation to the donor monomer, the efficiency that is attributed to the internal modes operating as energy reservoirs. The hydrogen bond shares about 15% of the initial excitation stored in both dimer-to-NO and NO-to-dimer processes as a result of strong coupling of the hydrogen bond with the proton-donor OH bond of the monomer. A small fraction of collisions proceeds through a complex-mode mechanism and lead to NO dissociation, the dissociated O atom showing a propensity to form a new hydrogen bond.

Total, partial and differential ionization cross sections in proton-hydrogen collisions at low energy

Energy Technology Data Exchange (ETDEWEB)

Zou, Shiyang [Graduate University for Advanced Studies, School of Mathematical and Physical Science, Toki, Gifu (Japan); Pichl, Lukas [University of Aizu, Foundation of Computer Science Laboratory, Aizuwakamatsu, Fukushima (Japan); Kimura, Mineo [Yamaguchi Univ., Graduate School of Science and Engineering, Ube, Yamaguchi (Japan); Kato, Takako [National Inst. for Fusion Science, Toki, Gifu (Japan)

2003-01-01

Single-differential, partial and total ionization cross sections for the proton-hydrogen collision system at low energy range (0.1-10 keV/amu) are determined by using the electron translation factor corrected molecular-orbital close-coupling method. Full convergence of ionization cross sections as a function of H{sub 2}{sup +} molecular basis size is achieved by including up to 10 bound states, and 11 continuum partial waves. The present cross sections are in an excellent agreement with the recent experiments of Shah et al., but decrease more rapidly than the cross sections measured by Pieksma et al. with decreasing energy. The calculated cross section data are included in this report. (author)

Atomic data on inelastic processes in low-energy manganese-hydrogen collisions

Science.gov (United States)

Belyaev, Andrey K.; Voronov, Yaroslav V.

2017-10-01

Aims: The aim of this paper is to calculate cross sections and rate coefficients for inelastic processes in low-energy Mn + H and Mn+ + H- collisions, especially, for processes with high and moderate rate coefficients. These processes are required for non-local thermodynamic equilibrium (non-LTE) modeling of manganese spectra in cool stellar atmospheres, and in particular, for metal-poor stars. Methods: The calculations of the cross sections and the rate coefficients were performed by means of the quantum model approach within the framework of the Born-Oppenheimer formalism, that is, the asymptotic semi-empirical method for the electronic MnH molecular structure calculation followed by the nonadiabatic nuclear dynamical calculation by means of the multichannel analytic formulas. Results: The cross sections and the rate coefficients for low-energy inelastic processes in manganese-hydrogen collisions are calculated for all transitions between 21 low-lying covalent states and one ionic state. We show that the highest values of the cross sections and the rate coefficients correspond to the mutual neutralization processes into the final atomic states Mn(3d54s(7S)5s e 6S), Mn(3d54s(7S)5p y 8P°), Mn(3d54s(7S)5s e 8S), Mn(3d54s(7S)4d e 8D) [the first group], the processes with the rate coefficients (at temperature T = 6000 K) of the values 4.38 × 10-8, 2.72 × 10-8, 1.98 × 10-8, and 1.59 × 10-8 cm3/ s, respectively, that is, with the rate coefficients exceeding 10-8 cm3/ s. The processes with moderate rate coefficients, that is, with values between 10-10 and 10-8 cm3/ s include many excitation, de-excitation, mutual neutralization and ion-pair formation processes. In addition to other processes involving the atomic states from the first group, the processes from the second group include those involving the following atomic states: Mn(3d5(6S)4s4p (1P°) y 6P°), Mn(3d54s(7S)4d e 6D), Mn(3d54s(7S)5p w 6P°), Mn(3d5(4P)4s4p (3P°) y 6D°), Mn(3d5(4G)4s4p (3P°) y 6F�

Electron-molecule collisions

CERN Document Server

Takayanagi, Kazuo

1984-01-01

Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

Antiproton collisions with molecular hydrogen

DEFF Research Database (Denmark)

Lühr, Armin Christian; Saenz, Alejandro

2008-01-01

Theoretical antiproton and proton cross sections for ionization and excitation of hydrogen molecules as well as energy spectra of the ionized electrons were calculated in the impact-energy range from 8  to  4000  keV. The cross sections were computed with the close-coupling formulation of the sem......Theoretical antiproton and proton cross sections for ionization and excitation of hydrogen molecules as well as energy spectra of the ionized electrons were calculated in the impact-energy range from 8  to  4000  keV. The cross sections were computed with the close-coupling formulation...

Momentum Transfer and Viscosity from Proton-Hydrogen Collisions Relevant to Shocks and Other Astrophysical Environments

International Nuclear Information System (INIS)

Schultz, David Robert; Krstic, Predrag S.; Lee, Teck G.; Raymond, J.C.

2008-01-01

The momentum transfer and viscosity cross sections for proton-hydrogen collisions are computed in the velocity range of ∼200-20,000 km s -1 relevant to a wide range of astrophysical environments such as SNR shocks, the solar wind, winds within young stellar objects or accretion disks, and the interstellar protons interacting with the heliosphere. A variety of theoretical approaches are used to arrive at a best estimate of these cross sections in this velocity range that smoothly connect with very accurate results previously computed for lower velocities. Contributions to the momentum transfer and viscosity cross sections from both elastic scattering and charge transfer are included

Wave-packet continuum-discretization approach to ion-atom collisions including rearrangement: Application to differential ionization in proton-hydrogen scattering

Science.gov (United States)

Abdurakhmanov, I. B.; Bailey, J. J.; Kadyrov, A. S.; Bray, I.

2018-03-01

In this work, we develop a wave-packet continuum-discretization approach to ion-atom collisions that includes rearrangement processes. The total scattering wave function is expanded using a two-center basis built from wave-packet pseudostates. The exact three-body Schrödinger equation is converted into coupled-channel differential equations for time-dependent expansion coefficients. In the asymptotic region these time-dependent coefficients represent transition amplitudes for all processes including elastic scattering, excitation, ionization, and electron capture. The wave-packet continuum-discretization approach is ideal for differential ionization studies as it allows one to generate pseudostates with arbitrary energies and distribution. The approach is used to calculate the double differential cross section for ionization in proton collisions with atomic hydrogen. Overall good agreement with experiment is obtained for all considered cases.

High energy physics at Tufts University. Progress report

International Nuclear Information System (INIS)

1976-09-01

In the past year the Bubble Chamber Group has been involved in a wide range of activities in experimental high energy physics. Beam momenta varying from 2.9 to 300 GeV/c; bubble chambers including the FNAL 30-inch, BNL 80-inch, ANL 12-foot and FNAL 15-foot; targets which include hydrogen, deuterium, hydrogen with downstream plate, and deuterium with downstream spark chambers; beam particles including K - , anti p and p--one is still waiting for neutrinos--were used. A search was made for exotic particles and charmed particles, continued to study strange baryons and mesons, probed the dimensions of the ''fireball,'' and studied multiplicities and correlations in high energy collisions. The following progress in each of the activities which have taken place is summarized. A list of publications is included

Collisions of low-energy multicharged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Crandall, D.H.

1981-01-01

Experimental measurements of cross sections for collisions of multiply charged ions with atoms at the lowest attainable collision energies are reported. Emphasis is on electron capture from hydrogen atoms by multiply charged ions at energies below 1 keV/amu. The principal effort is the development of a merged-ion-atom-beams apparatus for studies down to 1 eV/amu relative energy

One- and two-electron processes in collisions between hydrogen molecules and slow highly charged ions

International Nuclear Information System (INIS)

Wells, E.; Carnes, K.D.; Tawara, H.; Ali, R.; Sidky, Emil Y.; Illescas, Clara; Ben-Itzhak, I.

2005-01-01

A coincidence time-of-flight technique coupled with projectile charge state analysis was used to study electron capture in collisions between slow highly charged ions and hydrogen molecules. We found single electron capture with no target excitation to be the dominant process for both C 6+ projectiles at a velocity of 0.8 atomic units and Ar 11+ projectiles at v 0.63 a.u. Double electron capture and transfer excitation, however, were found to be comparable and occur about 30% of the time relative to single capture. Most projectiles (96%) auto-ionize quickly following double capture into doubly excited states. The data are compared to classical and quantum mechanical model calculations

High energy hadron-hadron collisions. Annual progress report

International Nuclear Information System (INIS)

Chou, T.T.

1979-03-01

Work on high energy hadron-hadron collisions in the geometrical model, performed under the DOE Contract No. EY-76-S-09-0946, is summarized. Specific items studied include the behavior of elastic hadron scatterings at super high energies and the existence of many dips, the computation of meson radii in the geometrical model, and the hadronic matter current effects in inelastic two-body collisions

Experimental investigations of hydrogen cluster ions

International Nuclear Information System (INIS)

Lumig, H.A. van.

1978-01-01

Experiments to obtain information about the structure and stability of small hydrogen cluster ions have been performed. Attenuation and fragmentation measurements are presented of hydrogen cluster ions colliding with nitrogen, argon, hydrogen and helium over fixed energy ranges. The total collision and differential fragmentation cross sections are tabulated. (C.F.)

Demonstration of a Prototype Hydrogen Sensor and Electronics Package - Progress Report 2

Energy Technology Data Exchange (ETDEWEB)

Wu, Amanda S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brosha, Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-06-14

This is the second progress report on the demonstration of a prototype hydrogen sensor and electronics package. It goes into detail about the five tasks, four of which are already completed as of August 2016, with the final to be completed by January 26, 2017. Then the budget is detailed along with the planned work for May 27, 2016 to July 27, 2016.

Coupled-channel calculations of partial capture cross sections in multiply charged ion collisions with hydrogen

International Nuclear Information System (INIS)

Hansen, J.P.; Taulbjerg, K.; University of Tennessee, Knoxville, Tennessee 37996)

1989-01-01

Partial cross sections for electron capture in 1--50-keV collisions of Ar 6+ and Ar 8+ with atomic hydrogen have been calculated using an atomic expansion including two complete principal shells of final states (n=4,5 for Ar 6+ and n=5,6 for Ar 8+ ). The qualitative structure of the results is in good accord with a reaction window picture. The results for Ar 6+ ions are in agreement with published experimental data when precaution is taken with respect to uncertainties in absolute normalization of the data and with respect to a proper analysis of translation energy spectra at lower impact energies. The limited experimental data for Ar 8+ do not agree with the present results

Inelastic Transitions in Slow Collisions of Anti-Hydrogen with Hydrogen Atoms

Science.gov (United States)

Harrison, Robert; Krstic, Predrag

2007-06-01

We calculate excited adiabatic states and nonadiabatic coupling matrix elements of a quasimolecular system containing hydrogen and anti-hydrogen atoms, for a range of internuclear distances from 0.2 to 20 Bohrs. High accuracy is achieved by exact diagonalization of the molecular Hamiltionian in a large Gaussian basis. Nonadiabatic dynamics was calculated by solving MOCC equations. Positronium states are included in the consideration.

2010 Annual Progress Report DOE Hydrogen Program

Energy Technology Data Exchange (ETDEWEB)

None, None

2011-02-01

This report summarizes the hydrogen and fuel cell R&D activities and accomplishments in FY2009 for the DOE Hydrogen Program, including the Hydrogen, Fuel Cells, and Infrastructure Technologies Program and hydrogen-related work in the Offices of Science; Fossil Energy; and Nuclear Energy, Science, and Technology. It includes reports on all of the research projects funded by the DOE Hydrogen Program between October 2009 and September 2010.

Anisotropic intermolecular interaction and rotational ordering in hydrogen-containing solids. Progress report No. 12

Energy Technology Data Exchange (ETDEWEB)

1976-01-01

Progress is reviewed in these areas: nuclear spin-lattice relaxation in ortho-para mixtures of solid deuterium below T/sub lambda/; pulsed NMR experiments of matrix isolated HCl; stimulated Raman scattering in solid hydrogen and nitrogen; and infrared line broadening of matrix isolated molecules. (GHT)

Anisotropic intermolecular interaction and rotational ordering in hydrogen-containing solids. Progress report No. 12

International Nuclear Information System (INIS)

1976-01-01

Progress is reviewed in these areas: nuclear spin-lattice relaxation in ortho-para mixtures of solid deuterium below T/sub lambda/; pulsed NMR experiments of matrix isolated HCl; stimulated Raman scattering in solid hydrogen and nitrogen; and infrared line broadening of matrix isolated molecules

Partially collisional model of the Titan hydrogen torus

International Nuclear Information System (INIS)

Hilton, D.A.

1987-01-01

A numerical model was developed for atomic hydrogen densities in the Titan hydrogen torus. The effects of occasional collisions were included in order to accurately simulate physical conditions inferred from the Voyager 1 and 2 Ultraviolet Spectrometer (UVS) results of Broadfoot et al. (1981) and Sandel et al. (1982). The model employed Lagrangian perturbation of orbital elements of hydrogen atoms launched from Titan and Monte Carlo simulation of collisions and loss mechanisms. The torus is found to be azimuthally symmetric with the density sharply peaked at Titan's orbit, and decreasing rapidly in the outward and perpendicular directions and more gradually inward from 17 to 5 R/sub s/. The energetic hydrogen atoms from Saturn's upper atmosphere, first predicted by Shemansky and Smith (1982), were also investigated. Collisions of these Saturnian atoms with the torus population do not contribute to the torus density, and will lead to a net loss of torus atoms if their launch speeds from Saturn extend above 40 km/sec. The Saturnian atoms produce a corona which was modeled using the theory of Chamberlain (1963)

Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin

Directory of Open Access Journals (Sweden)

Xiaoping Li

2010-01-01

Full Text Available Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2–H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2–H2. Our results agree well with previous ab initio work (where those data exist; the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2–H2 for frequencies from the far infrared to 20 000 cm−1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.

CONFERENCE: Photon-photon collisions

International Nuclear Information System (INIS)

Anon.

1983-01-01

Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists

Hydrogen-Antihydrogen Collisions at Cold Temperatures

Science.gov (United States)

Zygelman, Bernard

2001-05-01

With the CERN anti-proton de-accelerator now on line, it is anticipated that antihydrogen ( \\overline H) atoms will be created, cooled, and stored in large numbers (M. H. Holzscheitner and M. Charlton, Rep. Prog. Phys. 62),1 (1999). It has recently been proposed that the introduction of cold, spin-polarized, hydrogen atoms into a gas of trapped anti-hydrogen could allow the sympathetic cooling of the anti-hydrogen into the sub-Kelvin regime (P. Froelich, S. Jonsell, A.Saenz, B. Zygelman, and A. Dalgarno, Phys. Rev. Lett. 84), 4577 (2000). In this talk we will present the results of calculations that estimate the rate of elastic scattering of H with \\overline H, and compare that to the rate in which the fragmentation reaction, H + \\overline H arrow p \\overline p + e^+ e^- occurs and limits the utility of sympathetic cooling. Unlike the ground state of the H2 system, the H \\overline H system possesses a non-vanishing electric dipole moment (B. Zygelman, A. Saenz, P. Froelich, S. Jonsell and A. Dalgarno, Phys. Rev. A, in Press (2001).) that allows for the additional inelastic reaction H + \\overline H arrow H\\overline H^* + h ν , where H \\overline H^* is a quasi-bound state of the hydrogen-antihydrogen complex. The rate for radiative association into quasi-bound states of the H \\overline H^* complex will be presented and we will explore the viability for the spectroscopic study of this novel four-body matter-antimatter system. Collaborators in this study include, A. Dalgarno, P. Froelich, A. Saenz and S. Jonsell. I wish to thank the Institute for Theoretical Atomic and Molecular Physics (ITAMP) for their hospitality and support during sabbatical leave where part of this work was done. Partial support was provided by NSF grants to the Smithsonian Institution and Harvard University for ITAMP.

Role of atom--atom inelastic collisions in two-temperature nonequilibrium plasmas

International Nuclear Information System (INIS)

Kunc, J.A.

1987-01-01

The contribution of inelastic atom--atom collisions to the production of electrons and excited atoms in two-temperature (with electron temperature T/sub e/, atomic temperature T/sub a/, and atomic density N/sub a/), steady-state, nonequilibrium atomic hydrogen plasma is investigated. The results are valid for plasmas having large amounts of atomic hydrogen as one of the plasma components, so that e--H and H--H inelastic collisions and interaction of these atoms with radiation dominate the production of electrons and excited hydrogen atoms. Densities of electrons and excited atoms are calculated in low-temperature plasma, with T/sub e/ and T/sub a/≤8000 K and 10 16 cm -3 ≤N/sub a/≤10 18 cm -3 , and with different degrees of the reabsorption of radiation. The results indicate that inelastic atom--atom collisions are important for production of electrons and excited atoms in partially ionized plasmas with medium and high atomic density and temperatures below 8000 K

Laser-assisted electron-atom collisions

International Nuclear Information System (INIS)

Mason, N.J.

1989-01-01

New developments in our understanding of the electron-atom collision process have been made possible by combining the use of highly monochromatic electron beams and intense CO 2 lasers. This paper reviews such experiments and discusses possible future progress in what is a new field in atomic collision physics. (author)

Isotope exchange reactions in hydrogen mixtures

International Nuclear Information System (INIS)

Czaplinski, W.; Gula, A.; Kravtsov, A.; Mikhailov, A.; Popov, N.

1990-12-01

The rates of isotopic exchange for the excited states of muonic hydrogen are calculated as functions of collision energy. Ground state population q 1s for different collision energies, target densities and isotope concentrations is obtained. It is shown that for principal quantum numbers n > 5 the isotopic exchange still considerably influences the value of q 1s . (author)

Multi-property isotropic intermolecular potentials and predicted spectral lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) for H2sbnd Ne, -Kr and -Xe

Science.gov (United States)

El-Kader, M. S. A.; Godet, J.-L.; Gustafsson, M.; Maroulis, G.

2018-04-01

Quantum mechanical lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) at room temperature (295 K) are computed for gaseous mixtures of molecular hydrogen with neon, krypton and xenon. The induced spectra are detected using theoretical values for induced dipole moment, pair-polarizability trace and anisotropy, hyper-polarizability and updated intermolecular potentials. Good agreement is observed for all spectra when the literature and the present potentials which are constructed from the transport and thermo-physical properties are used.

Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

Science.gov (United States)

Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

2011-06-01

The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

Coupled-channels calculations of excitation and ionization in ion-atom collisions

International Nuclear Information System (INIS)

Martir, M.H.

1981-01-01

A numerical method has been used to compute excitation and ionization cross sections for ion-atom collisions. The projectile is treated classically and follows a straight line, constant velocity path (unless indicated otherwise). The wave function that describes the atom is expanded about the target in a truncated Hilbert space. The interaction between the projectile and the target atom is treated as a time dependent perturbation. A unitary time development operator, U, propagates the wave function from a time prior to the collision to a time after the collision in small time steps. Contrary to first-order theories, coupling between states is allowed. This method has been improved so that any number of partial waves can be included in the wave function expansion. This method has been applied to study negatively charged projectiles. Cross sections are obtained for collisions of antiprotons on atomic hydrogen (30 keV to 372 keV) and compared with cross sections of protons on atomic hydrogen to explore the Z/sub P/ dependence. The antiproton-hydrogen results were converted into electron-hydrogen values with E/sub e/ = E/sub P/(m/sub e//m/sub P/) (15 eV to 200 eV) and compared to experimental values. The method is then applied to study vacancy production from the L-shell. The partial wave convergence of the cross sections was carefully studied for s through g waves. Collisions between protons (and alpha-particles) and argon are studied to explore the Z/sub P/ dependence of the cross sections. The cross section ratio sigma(α)/(4sigma(p)) is compared to experiment

Positron-atom collisions

International Nuclear Information System (INIS)

Drachman, R.J.

1984-01-01

The past decade has seen the field of positron-atom collisions mature into an important sub-field of atomic physics. Increasingly intense positron sources are leading towards a situation in which electron and positron collision experiments will be on almost an equal footing, challenging theory to analyze their similarities and differences. The author reviews the advances made in theory, including dispersion theory, resonances, and inelastic processes. A survey of experimental progress and a brief discussion of astrophysical positronics is also included. (Auth.)

Laser spectroscopic measurements of fine structure changing cross sections of alkali earth ions in collisions with molecular hydrogen (H2, D2)

International Nuclear Information System (INIS)

Moriwaki, Yoshiki; Matsuo, Yukari; Fukuyama, Yoshimitsu; Morita, Norio

2006-01-01

Production of alkali earth ions (Ca + , Sr + and Ba + ) by means of a laser ablation technique and measurement of their laser-induced fluorescence, cross sections of collision-induced transitions between the np 2 P J fine structure levels (n= 4, 5 and 6 for Ca + , Sr + and Ba + , respectively) due to collisions with hydrogen molecules at room temperature (298 K) has been performed. The cross sections thus determined for the collisions with H 2 and D 2 are σ(Ca + : 4p 2 P 3/2 → 4p 2 P 1/2 ) = 20.5 ± 0.5, 27.1 ± 1.3 A 2 , σ(Ca + : 4p 2 P 1/2 → 4p 2 P 3/2 ) = 13.2 ± 0.6, 18.7 ± 0.8 A 2 , σ(Sr + : 5p 2 P 3/2 → 5p 2 P 1/2 ) = 22.7 ± 0.4, 18.0 ± 0.4 A 2 and σ(Ba + : 6p 2 P 3/2 → 6p 2 P 1/2 ) 10.4 ± 0.1, 3.4 ± 0.2 A 2 , respectively

Membrane pumping technology, helium and hydrogen isotopes separation in the fusion hydrogen

International Nuclear Information System (INIS)

Pigarov, A.Yu.; Pistunovich, V.I.; Busnyuk, A.O.

1994-01-01

A gas pumping system for the ITER, improved by implementation of superpermeable membranes for selective hydrogen isotope exhaust, is considered. The study of the pumping capability of a niobium membrane for a hydrogen-helium mixture has been fulfilled. The membrane superpermeability can be only realized for atomic hydrogen. Helium does not pass through the membrane, and its presence does not affect the hydrogen pumping. A detailed Monte Carlo simulation of gas behavior for the experimental facility has been done. The probability of permeation for a hydrogen atom for one collision with the membrane is ∼0.1; the same probability of molecule permeation is ∼10 -5 . The probability for atomization, i.e. re-emission of an atomizer is ∼0.2; the probability of recombination of an atom is ∼0.2

Correlated charge changing ion-atom collisions: Progress report for the period March 15, 1988--March 14, 1989

International Nuclear Information System (INIS)

Bernstein, E.M.; Tanis, J.A.

1989-04-01

This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant FG02-87ER13778 from March 15, 1988 through atomic interactions in collisions of highly charged projectiles with neutral targets. Processes involving excitation, ionization, and charge transfer are investigated using coincidence techniques to isolate and identify specific interaction mechanisms. New measurements were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, and Western Michigan University. The principal new results are summarized

Total projectile electron loss cross sections of U^{28+} ions in collisions with gaseous targets ranging from hydrogen to krypton

Directory of Open Access Journals (Sweden)

G. Weber

2015-03-01

Full Text Available Beam lifetimes of stored U^{28+} ions with kinetic energies of 30 and 50  MeV/u, respectively, were measured in the experimental storage ring of the GSI accelerator facility. By using the internal gas target station of the experimental storage ring, it was possible to obtain total projectile electron loss cross sections for collisions with several gaseous targets ranging from hydrogen to krypton from the beam lifetime data. The resulting experimental cross sections are compared to predictions by two theoretical approaches, namely the CTMC method and a combination of the DEPOSIT code and the RICODE program.

Electron capture in ion-molecule collisions at intermediate energy

International Nuclear Information System (INIS)

Kumura, M.

1986-01-01

Recent progress of theoretical charge transfer study in ion-molecule collisions at the intermediate energy is reviewed. Concept of close and distant collisions obtained from extensive ion-atom collision studies is identified so that it can be utilized to model two distinct collision processes. For a close collision, explicit representation of the whole collision complex is necessary to describe collision dynamics correctly, while a model potential approach for molecule is appropriate for a distant collision. It is shown that these two distinct models are indeed capable of reproducing experimental charge transfer cross sections. Some remarks for further theoretical study of ion-molecule collisions are also given. 21 refs., 8 figs

Comparison of hydrogen storage properties of pure Mg and milled ...

Indian Academy of Sciences (India)

Administrator

increase the hydriding and dehydriding rates, pure Mg was ground under hydrogen atmosphere (reactive .... Hydrogen storage properties of pure Mg and milled pure Mg. 833. Figure 3. ... elongated and flat shapes via collisions with the steel.

Laser driven source of spin polarized atomic deuterium and hydrogen

International Nuclear Information System (INIS)

Poelker, M.; Coulter, K.P.; Holt, R.J.

1993-01-01

Optical pumping of potassium atoms in the presence of a high magnetic field followed by spin exchange collisions with deuterium (hydrogen) is shown to yield a high flux of spin polarized atomic deuterium (hydrogen). The performance of the laser driven source has been characterized as a function of deuterium (hydrogen) flow rate, potassium density, pump laser power, and magnetic field. Under appropriate conditions, the authors have observed deuterium atomic polarization as high as 75% at a flow rate 4.2x10 17 atoms/second. Preliminary results suggest that high nuclear polarizations are obtained in the absence of weak field rf transitions as a result of a spin temperature distribution that evolves through frequent H-H (D-D) collisions

Target continuum distorted-wave theory for collisions of fast protons with atomic hydrogen

International Nuclear Information System (INIS)

Crothers, D.S.F.; Dunseath, K.M.

1990-01-01

By considering the target continuum distorted-wave (TCDW) theory as the high-energy limit of the half-way house variational continuum distorted-wave theory, it is shown not only that there is no intermediate elastic divergence but also that the second-order amplitude based on a purely elastic intermediate state is of order υ -6 and is thus negligible. The residual inelastic TCDW theory is developed to second-order at high velocities. It is used to describe charge exchange during collisions of fast protons with atomic hydrogen. Using an on-shell peaking approximation and considering 1s-1s capture it is shown that the residual purely second-order transition amplitude comprises two terms, one real term of order υ -6 and one purely imaginary term of order υ -7 ln υ. At 5 MeV laboratory energy, it is shown that these are negligible. It is also shown that the υ -5 first-order term gives a differential cross section in very good agreement with an experiment at all angles including forward, interference minimum, Thomas maximum and large angles, particularly having folded our theory over experimental resolution. (author)

Experiments with cold hydrogen atoms

International Nuclear Information System (INIS)

Leonas, V.B.

1981-01-01

Numerous investigations of atomic processes in Waseous phase on the surface with participation of ''cold'' hydrogen atoms, made during the last years, are considered. The term ''cold atom'' means the range of relative collision energies E<10 MeV (respectively 'ultracold ' atoms at E< or approximately 1 MeV) which corresponds to the range of temperatures in tens (units) of K degrees. Three main ranges of investigations where extensive experimental programs are realized are considered: study of collisional processes with hydrogen atom participation, hydrogen atoms being of astrophysical interest; study of elastic atom-molecular scattering at superlow energies and studies on the problem of condensed hydrogen. Hydrogen atoms production is realized at dissociation in non-electrode high-frequency or superhigh-frequency discharge. A method of hydrogen quantum generator and of its modifications appeared to be rather an effective means to study collisional changes of spin state of hydrogen atoms. First important results on storage and stabilization of the gas of polarized hydrogen atoms are received

Relativistic Collisions of Structured Atomic Particles

CERN Document Server

Voitkiv, Alexander

2008-01-01

The book reviews the progress achieved over the last decade in the study of collisions between an ion and an atom in which both the atomic particles carry electrons and can undergo transitions between their internal states -- including continua. It presents the detailed considerations of different theoretical approaches, that can be used to describe collisions of structured atomic particles for the very broad interval of impact energies ranging from 0.5--1 MeV/u till extreme relativistic energies where the collision velocity very closely approaches the speed of light.

Recent Progress and New Perspectives on Metal Amide and Imide Systems for Solid-State Hydrogen Storage

Directory of Open Access Journals (Sweden)

Sebastiano Garroni

2018-04-01

Full Text Available Hydrogen storage in the solid state represents one of the most attractive and challenging ways to supply hydrogen to a proton exchange membrane (PEM fuel cell. Although in the last 15 years a large variety of material systems have been identified as possible candidates for storing hydrogen, further efforts have to be made in the development of systems which meet the strict targets of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU and U.S. Department of Energy (DOE. Recent projections indicate that a system possessing: (i an ideal enthalpy in the range of 20–50 kJ/mol H2, to use the heat produced by PEM fuel cell for providing the energy necessary for desorption; (ii a gravimetric hydrogen density of 5 wt. % H2 and (iii fast sorption kinetics below 110 °C is strongly recommended. Among the known hydrogen storage materials, amide and imide-based mixtures represent the most promising class of compounds for on-board applications; however, some barriers still have to be overcome before considering this class of material mature for real applications. In this review, the most relevant progresses made in the recent years as well as the kinetic and thermodynamic properties, experimentally measured for the most promising systems, are reported and properly discussed.

High Energy Physics progress report, 1985-1986

International Nuclear Information System (INIS)

1986-01-01

Progress is reported for experiments addressing: hadron-nucleus collisions, charm production from pp collisions at 400 and 800 GeV/c, radial excitation of rho, direct photon and charmonium production, and search for a quark-gluon plasma in proton-antiproton collisions at 2 TeV

Direct-hydrogen-fueled proton-exchange-membrane fuel cell system for transportation applications. Hydrogen vehicle safety report

Energy Technology Data Exchange (ETDEWEB)

Thomas, C.E. [Directed Technologies, Inc., Arlington, VA (United States)

1997-05-01

This report reviews the safety characteristics of hydrogen as an energy carrier for a fuel cell vehicle (FCV), with emphasis on high pressure gaseous hydrogen onboard storage. The authors consider normal operation of the vehicle in addition to refueling, collisions, operation in tunnels, and storage in garages. They identify the most likely risks and failure modes leading to hazardous conditions, and provide potential countermeasures in the vehicle design to prevent or substantially reduce the consequences of each plausible failure mode. They then compare the risks of hydrogen with those of more common motor vehicle fuels including gasoline, propane, and natural gas.

Electron detachment by H- + H- collisions

International Nuclear Information System (INIS)

Chibisov, M.I.; Yavlinskii, Yu.N.

1994-01-01

The autoionization channels for electrons detachment in collisions of two negative hydrogen ions in the energy range 300 - 500 eV and > 500 eV are investigated. In small energy range at large inter-ion distances the asymptotic approximation is used; at high energies - perturbation theory and classical motion are used. 18 refs., 3 figs

Asymptotic form of the charge exchange cross section in the three body rearrangement collisions

Science.gov (United States)

Omidvar, K.

1975-01-01

A three body general rearrangement collision is considered where the initial and final bound states are described by the hydrogen-like wave functions. Mathematical models are developed to establish the relationships of quantum number, the reduced mass, and the nuclear charge of the final state. It is shown that for the low lying levels, the reciprocal of n cubed scaling law at all incident energies is only approximately satisfied. The case of the symmetric collisions is considered and it is shown that for high n and high incident energy, E, the cross section behaves as the reciprocal of E cubed. Zeros and minima in the differential cross sections in the limit of high n for protons on atomic hydrogen and positrons on atomic hydrogen are given.

Small-angle scattering of ions or atoms by atomic hydrogen

International Nuclear Information System (INIS)

Franco, V.

1982-01-01

A theory for small-angle scattering of arbitrary medium- or high-energy atoms or ions by atomic hydrogen is described. Results are obtained in terms of the known closed-form and easily calculable Glauber-approximation scattering amplitudes for electron-hydrogen collisions and for collisions between the nucleus (treated as one charged particle) of the ion or atom and the hydrogen atom, and in terms of the transition form factor of the arbitrary ion or atom. Applications are made to the angular differential cross sections for the excitation of atomic hydrogen to its n = 2 states by singly charged ground-state helium ions having velocities of roughly between 1/2 and 1 a.u. The differential cross sections are obtained in terms of electron-hydrogen amplitudes and the known He + ground-state form factor. Comparisons are made with other calculations and with recent measurements. The results are in good agreement with the data. It is seen that the effect of the He + electron is to produce significant constructive interference at most energies

Recent progress in nonperturbative electromagnetic lepton-pair production with capture in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Wells, J.C.; Oberacker, V.E.; Umar, A.S.

1993-01-01

The prospect of new colliding-beam accelerators capable of producing collisions of highly stripped high-Z ions, at fixed-target energies per nucleon up to 20 TeV or more, has motivated much interest in lepton-pair production from the QED vacuum. The time-dependent and essentially classical electromagnetic fields involved in such collisions contain larger Fourier components which give rise to sizable lepton-pair production in addition to many other exotic particles. The process of electron-positron production with electron capture is a principal beam-loss mechanism for highly charged ions in a storage ring. In this process, the electron is created in a bound state of one of the participant heavy ions (most likely the 1s state), thus changing the ion's charge state and causing it to be deflected out of the beam. There is a long and sometimes controversial history concerning the use of perturbative methods in studying electromagnetic lepton-pair production; however, reliable perturbative calculations have been used as input into design models for the Relativistic Heavy-Ion Collider (RHIC). Applying perturbation theory to these processes at high energies and small impact parameters results in probabilities which violate unitarity, and cross sections which violate the Froissart bound. This evidence, along with the initial nonperturbative studies, suggests that higher-order QED effects will be important for extreme relativistic collisions. Clearly, large nonperturbative effects in electron-pair production with capture would have important implications for RHIC. In this paper, the authors briefly discuss recent progress in nonperturbative studies of the capture problem. In Section 2, they state the Dirac equation for a lepton in the time-dependent external field of a heavy ion which must be solved to compute lepton-capture probabilities. Section 4 surveys results from recent applications of coupled-channel and lattice techniques to the lepton-capture problem

Recent theoretical studies of slow collisions between plasma impurity ions and H or He atoms

Energy Technology Data Exchange (ETDEWEB)

Fritsch, W. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Theoretische Physik; Tawara, H.

1997-01-01

We review recent progress in theoretical studies of slow collisions between light plasma impurity ions and atomic hydrogen or helium. We start with a brief overview of theory work that has been done by various groups in the past. We then proceed to discuss work that is published in the last two years. For the systems of Be{sup 2+}-He, Be{sup 4+}-He and C{sup 5+}-He we present yet unpublished work of our own. All of this work broadens our knowledge about systems that are of interest for the fusion community. Some of the new information is found to be at variance with what is known from other sources and hence needs further analysis. (author)

Experimental investigation of electron capture from atomic hydrogen and deuterium by alpha particles: Progress report, 15 September 1987-14 September 1988

International Nuclear Information System (INIS)

Gay, T.J.

1988-08-01

During the last nine months, we have made several improvements to the apparatus, measured differential and total cross sections for the reaction, He ++ + He/1s/sup 2/) /yields/ He(/Sigma/n,/ital ell/)+He/sup ++/, and some important progress in understanding the physics of ionizing collisions relevant for fusion plasmas. 6 refs., 5 figs

Calculations on Electron Capture in Low Energy Ion-Molecule Collisions

Energy Technology Data Exchange (ETDEWEB)

Stancil, P.C. [Oak Ridge National Lab., TN (United States); Zygelman, B. [W.M. Keck Lab. for Computational Physics, Univ. of Nevada, Las Vegas, NV (United States); Kirby, K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

1997-12-31

Recent progress on the application of a quantal, molecular-orbital, close-coupling approach to the calculation of electron capture in collisions of multiply charged ions with molecules is discussed. Preliminary results for single electron capture by N{sup 2+} with H{sub 2} are presented. Electron capture by multiply charged ions colliding with H{sub 2} is an important process in laboratory and astrophysical plasmas. It provides a recombination mechanism for multiply charged ions in x-ray ionized astronomical environments which may have sparse electron and atomic hydrogen abundances. In the divertor region of a tokamak fusion device, charge exchange of impurity ions with H{sub 2} plays a role in the ionization balance and the production of radiative energy loss leading to cooling, X-ray and ultraviolet auroral emission from Jupiter is believed to be due to charge exchange of O and S ions with H{sub 2} in the Jovian atmosphere. Solar wind ions interacting with cometary molecules may have produced the x-rays observed from Comet Hyakutake. In order to model and understand the behavior of these environments, it is necessary to obtain total, electronic state-selective (ESS), and vibrational (or rotational) state-selective (VSS) capture cross sections for collision energies as low as 10 meV/amu to as high as 100 keV/amu in some instances. Fortunately, charge transfer with molecular targets has received considerable experimental attention. Numerous measurements have been made with flow tubes, ion traps, and ion beams. Flow tube and ion trap studies generally provide information on rate coefficients for temperatures between 800 K and 20,000 K. In this article, we report on the progress of our group in implementing a quantum-mechanical Molecular Orbital Close Coupling (MOCC) approach to the study of electron capture by multiply charged ions in collisions with molecules. We illustrate this with a preliminary investigation of Single Electron Capture (SEC) by N{sup 2+} with H

CERN: LHC progress

International Nuclear Information System (INIS)

Anon.

1993-01-01

The push for CERN's next major project, the LHC proton collider to be built in the 27-kilometre LEP tunnel, is advancing on a wide front. For the machine itself, there has been considerable progress in the detailed design. While the main thrust is for proton-proton collisions, heavy ions are also on the LHC collision menu. On the experimental side, proposals are coming into sharper focus. For the machine, the main aim is for the highest possible proton collision energies and collision rates in the confines of the existing LEP tunnel, and the original base design looked to achieve these goals in three collision regions. Early discussions on the experimental programme quickly established that the most probable configuration would have two collision regions rather than three. This, combined with hints that the electronics of several detectors would have to handle several bunch crossings at a time, raised the question whether the originally specified bunch spacing of 15 ns was still optimal

Alignment and orientation in ion/endash/atom collisions

International Nuclear Information System (INIS)

Kimura, M.; Lane, N.F.

1987-01-01

Recent progress in the theoretical study of alignment and orientation in atom-atom and ion-atom collisions at intermediate energies is reviewed. Recent systematic studies of the alignment and orientation of electronic charge cloud distributions of excited states resulting from such collisions clearly have provided more detailed information about the underlying collision dynamics. However, since accurate determination of these parameters is quite difficult, both theoretically and experimentally, a close collaboration between theory and experiment is necessary for a deeper understanding of the collision dynamics. A more complete approach, where the full density matrix is determined, is also discussed

[Reactive collisions of high-temperature systems

International Nuclear Information System (INIS)

Graff, M.M.

1990-01-01

The object of this research is to study reactivity at superthermal collision energies using a fast neutral beam that is generated by photodetachment. Systems scheduled for initial study include basic oxygen-hydrogen reactions. Unfortunately, we can not yet report realization of this goal, but during this funding period we have made advances that are anticipated to lead to successful measurements during the next year. The parameters described below refer to the model system O + H 2 → OH + H. The basic design involves the collision of fast neutrals, created by photodetachment of the corresponding negative molecular ion, with a stable reactant gas in a collision cell. Products are detected by ionization and mass analysis. We are equipped to study rotational effects on reactivity by comparing results for rotational levels J = 0 and 1 of H 2 . Highlights during the funding period are given in this report

Processes involved in pion capture in hydrogen-containing molecules

International Nuclear Information System (INIS)

Horvath, D.

1983-03-01

A systematic analysis is presented of the possible elementary processes determining the fate of negative pions stopped in hydrogen-containing samples. Using a phenomenological description in comparison with the available experimental information on pion capture in hydrogen, it is shown that the formation and decay of pπ - atoms in compounds Zsub(m)Hsub(n) are determined mainly by the processes of Auger capture in a molecular orbit ZHπ - , transition from molecular to atomic orbit, transfer of pions to atoms Z in collisions pπ - +Z, and nuclear capture in collisions pπ - +H. The recent assumption of a considerable role of the processes of radiative atomic capture in bound hydrogen atoms, nuclear capture of pions by protons from the molecular state ZHπ - , or 'inner' transfer of the pion via tunnelling through the bond Z-H is not supported by the theory and contradicts the experimental data

Measurements of scattering processes in negative ion-atom collisions: Progress report, 1 September 1988--31 August 1989

International Nuclear Information System (INIS)

Kvale, T.J.

1989-01-01

The main emphasis of this research effort is the simultaneous study of several of the scattering processes that occur in negative ion-atom collisions. These include: elastic scattering, target excitation/ionization, single electron detachment, and double electron detachment. The measurements will provide absolute total and differential cross sections for the aforementioned processes. These are extremely valuable in providing stringent tests of the approximations used in the various theoretical calculations. This period covers the first year of the grant and the vast majority of the activity was directed toward construction of the apparatus needed to carry out the proposed measurements. Progress toward these goals are summarized. 2 refs., 1 fig

Electron's anomalous magnetic-moment effects on electron-hydrogen elastic collisions in the presence of a circularly polarized laser field

International Nuclear Information System (INIS)

Elhandi, S.; Taj, S.; Attaourti, Y.; Manaut, B.; Oufni, L.

2010-01-01

The effect of the electron's anomalous magnetic moment on the relativistic electronic dressing for the process of electron-hydrogen atom elastic collisions is investigated. We consider a laser field with circular polarization and various electric field strengths. The Dirac-Volkov states taking into account this anomaly are used to describe the process in the first order of perturbation theory. The correlation between the terms coming from this anomaly and the electric field strength gives rise to the strong dependence of the spinor part of the differential cross section (DCS) with respect to these terms. A detailed study has been devoted to the nonrelativistic regime as well as the moderate relativistic regime. Some aspects of this dependence as well as the dynamical behavior of the DCS in the relativistic regime have been addressed.

Formation of negative hydrogen ion: polarization electron capture and nonthermal shielding.

Science.gov (United States)

Ki, Dae-Han; Jung, Young-Dae

2012-09-07

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H(-)) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

Formation of negative hydrogen ion: Polarization electron capture and nonthermal shielding

International Nuclear Information System (INIS)

Ki, Dae-Han; Jung, Young-Dae

2012-01-01

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H − ) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

LHC: Collisions on course for 2007

CERN Document Server

2006-01-01

In the LHC tunnel and caverns, a particle accelerator and detectors are rapidly taking shape. At last week's Council meeting, delegates took stock of the year's progress towards first collisions in 2007.

A study on hazard types occurring in hydrogen facilities

International Nuclear Information System (INIS)

Cho, Nam Chul; Jae, Moo Sung; Eon, Yang Joon

2004-01-01

Hydrogen has ideal characteristics as an energy carrier. Hydrogen can be used as a clean fuel in a variety of energy end-use sectors including the conversion to electricity. After combustion, it produces only water. Therefore, the concept of hydrogen energy system has attracted much interest worldwide. But hydrogen has a defect that the explosion risk is high to an inflammable gas of a colorless, tasteless and odorless. Therefore, to use the hydrogen to the source of energy, hydrogen accident sequences and causes analysis must be needed. For this, hazard types occurring in hydrogen facilities have been considered through the case of domestic and foreign hydrogen accident in this study and hazard types to be considered are ignition, leaks, hydrogen dispersion, fire an explosion, storage vessel failure, vent and exhaust system, purging, condensation of air, hydrogen embrittlement, physiological hazard, and collisions during transportation

Inelastic collision rates of trapped metastable hydrogen

NARCIS (Netherlands)

Landhuis, D; Matos, L; Moss, SC; Steinberger, JK; Vant, K; Willmann, L; Greytak, TJ; Kleppner, D

We report the first detailed decay studies of trapped metastable (2S) hydrogen. By two-photon excitation of ultracold H samples, we have produced clouds of at least 5x10(7) magnetically trapped 2S atoms at densities greater than 4x10(10) cm(-3) and temperatures below 100 muK. At these densities and

Electron collision cross sections and radiation chemistry

International Nuclear Information System (INIS)

Hatano, Y.

1983-01-01

A survey is given of the cross section data needs in radiation chemistry, and of the recent progress in electron impact studies on dissociative excitation of molecules. In the former some of the important target species, processes, and collision energies are presented, while in the latter it is demonstrated that radiation chemistry is a source of new ideas and information in atomic collision research. 37 references, 4 figures

Electron capture, electron loss, and deexcitation of fast H(2 2S) and H(1 2S) atoms in collisions with molecular hydrogen and inert gases

International Nuclear Information System (INIS)

Roussel, F.; Pradel, P.; Spiess, G.

1977-01-01

Collisions of ground-state (1 2 S) and metastable (2 2 S) hydrogen atoms with rare gases and molecular hydrogen have been studied in the energy range 0.5--3.0 keV. For an acceptance angle of 55 mrad, the electron loss and the electron-capture cross sections of both H(1 2 S) and H(2 2 S) have been measured and compared with previous experimental values. The deexcitation cross section for H(2 2 S) has been deduced with the help of previously measured total-quenching cross sections for H(2 2 S). The ratio of the electron-capture cross sections for H(2 2 S) relative to H(1 2 S) is found to be very large for argon at low energies. The effects of large-angle scattering and of highly excited states of H are discussed

Liquid-phase chemical hydrogen storage: catalytic hydrogen generation under ambient conditions.

Science.gov (United States)

Jiang, Hai-Long; Singh, Sanjay Kumar; Yan, Jun-Min; Zhang, Xin-Bo; Xu, Qiang

2010-05-25

There is a demand for a sufficient and sustainable energy supply. Hence, the search for applicable hydrogen storage materials is extremely important owing to the diversified merits of hydrogen energy. Lithium and sodium borohydride, ammonia borane, hydrazine, and formic acid have been extensively investigated as promising hydrogen storage materials based on their relatively high hydrogen content. Significant advances, such as hydrogen generation temperatures and reaction kinetics, have been made in the catalytic hydrolysis of aqueous lithium and sodium borohydride and ammonia borane as well as in the catalytic decomposition of hydrous hydrazine and formic acid. In this Minireview we briefly survey the research progresses in catalytic hydrogen generation from these liquid-phase chemical hydrogen storage materials.

Energy dependence of the ionization of highly excited atoms by collisions with excited atoms

International Nuclear Information System (INIS)

Shirai, T.; Nakai, Y.; Nakamura, H.

1979-01-01

Approximate analytical expressions are derived for the ionization cross sections in the high- and low-collision-energy limits using the improved impulse approximation based on the assumption that the electron-atom inelastic-scattering amplitude is a function only of the momentum transfer. Both cases of simultaneous excitation and de-excitation of one of the atoms are discussed. The formulas are applied to the collisions between two excited hydrogen atoms and are found very useful for estimating the cross sections in the wide range of collisions energies

Collision data involving hydro-carbon molecules

International Nuclear Information System (INIS)

Tawara, H.; Itikawa, Y.; Nishimura, H.; Tanaka, H.; Nakamura, Y.

1990-07-01

Hydro-carbon molecules are abundantly produced when graphites are used as internal wall materials of hydrogen plasmas and strongly influence properties of low temperature plasmas near the edges as well as those of high temperature plasmas at the center. In this report, following simple description of the production mechanisms of hydro-carbon molecules under the interactions between graphite and hydrogen plasma, the present status of collision data for hydro-carbon molecules by electron impact is discussed and the relevant data are summarized in a series of figures and tables. It should also be noted that, in addition to fusion plasmas, these hydrocarbon data compiled here are quite useful in other applications such as plasma chemistry and material processing. (author)

Resonance formation in photon-photon collisions

International Nuclear Information System (INIS)

Gidal, G.

1988-08-01

Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the γγ* production of spin-one resonances. 37 refs., 17 figs., 5 tabs

Hydrogen from biomass

NARCIS (Netherlands)

Claassen, P.A.M.; Vrije, de G.J.

2006-01-01

Hydrogen is generally regarded as the energy carrier of the future. The development of a process for hydrogen production from biomass complies with the policy of the Dutch government to obtain more renewable energy from biomass. This report describes the progress of the BWP II project, phase 2 of

Electron transfer, ionization, and excitation atomic collisions

International Nuclear Information System (INIS)

Winter, T.G.; Alston, S.G.

1990-01-01

Basic atomic-collision processes at intermediate and high energies are being studied theoretically at Penn State by Alston and Winter. In the high velocity regime, single-electron capture is treated using a high order multiple-scattering approach; extensive comparison with experiment and analysis of mechanisms have been made. Fitting the calculated amplitude with a simple analytic form, the asymptotic velocity dependence of the cross section is obtained. The effect on the capture amplitude of altering the inner part of the internuclear potential has also been explored. In the intermediate velocity regime, earlier work on collisions between protons and hydrogenic-ion targets using a coupled-state approach is being extended to the two-electron helium target. 29 refs

Microalgal hydrogen production - A review.

Science.gov (United States)

Khetkorn, Wanthanee; Rastogi, Rajesh P; Incharoensakdi, Aran; Lindblad, Peter; Madamwar, Datta; Pandey, Ashok; Larroche, Christian

2017-11-01

Bio-hydrogen from microalgae including cyanobacteria has attracted commercial awareness due to its potential as an alternative, reliable and renewable energy source. Photosynthetic hydrogen production from microalgae can be interesting and promising options for clean energy. Advances in hydrogen-fuel-cell technology may attest an eco-friendly way of biofuel production, since, the use of H 2 to generate electricity releases only water as a by-product. Progress in genetic/metabolic engineering may significantly enhance the photobiological hydrogen production from microalgae. Manipulation of competing metabolic pathways by modulating the certain key enzymes such as hydrogenase and nitrogenase may enhance the evolution of H 2 from photoautotrophic cells. Moreover, biological H 2 production at low operating costs is requisite for economic viability. Several photobioreactors have been developed for large-scale biomass and hydrogen production. This review highlights the recent technological progress, enzymes involved and genetic as well as metabolic engineering approaches towards sustainable hydrogen production from microalgae. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recent Progress Toward Hydrogen Medicine: Potential of Molecular Hydrogen for Preventive and Therapeutic Applications

Science.gov (United States)

Ohta, Shigeo

2011-01-01

Persistent oxidative stress is one of the major causes of most lifestyle-related diseases, cancer and the aging process. Acute oxidative stress directly causes serious damage to tissues. Despite the clinical importance of oxidative damage, antioxidants have been of limited therapeutic success. We have proposed that molecular hydrogen (H2) has potential as a “novel” antioxidant in preventive and therapeutic applications [Ohsawa et al., Nat Med. 2007: 13; 688-94]. H2 has a number of advantages as a potential antioxidant: H2 rapidly diffuses into tissues and cells, and it is mild enough neither to disturb metabolic redox reactions nor to affect reactive oxygen species (ROS) that function in cell signaling, thereby, there should be little adverse effects of consuming H2. There are several methods to ingest or consume H2, including inhaling hydrogen gas, drinking H2-dissolved water (hydrogen water), taking a hydrogen bath, injecting H2-dissolved saline (hydrogen saline), dropping hydrogen saline onto the eye, and increasing the production of intestinal H2 by bacteria. Since the publication of the first H2 paper in Nature Medicine in 2007, the biological effects of H2 have been confirmed by the publication of more than 38 diseases, physiological states and clinical tests in leading biological/medical journals, and several groups have started clinical examinations. Moreover, H2 shows not only effects against oxidative stress, but also various anti-inflammatory and anti-allergic effects. H2 regulates various gene expressions and protein-phosphorylations, though the molecular mechanisms underlying the marked effects of very small amounts of H2 remain elusive. PMID:21736547

2009 Annual Progress Report: DOE Hydrogen Program, November 2009 (Book)

Energy Technology Data Exchange (ETDEWEB)

2009-11-01

This report summarizes the hydrogen and fuel cell R&D activities and accomplishments of the DOE Hydrogen Program for FY2009. It covers the program areas of hydrogen production and delivery; fuel cells; manufacturing; technology validation; safety, codes and standards; education; and systems analysis.

Correlated charge changing ion-atom collisions. Progress report, March 15, 1985-March 14, 1986

International Nuclear Information System (INIS)

Bernstein, E.M.; Tanis, J.A.

1986-04-01

X-ray emission associated with projectile charge-changing events in ion-atom collisions has been used to isolate and investigate excitation, ionization, and charge transfer, as well as combinations of these processes. New measurements were made of K-shell and L-shell resonant transfer and excitation (RTE) for 210 to 300 MeV 20 Ca/sup 10,11+/ + H 2 collisions and 230 to 610 MeV 41 Nb 31+ + H 2 collisions, respectively. Nonresonant transfer and excitation (NTE) was studied for 40 to 160 MeV S 13+ + Ne. Single-electron capture and loss measurements, requiring accel-decel techniques, were made for 2.5 to 200 MeV S 13+ on He. In the case of Ca/sup 16,17,18,19 + / + H 2 collisions the single capture cross cross sections exhibit a nonmonotonic energy dependence which we attribute to RTE. Double-electron capture in single collisions was investigated for S 13+ + He and Ne and Ar 15+ + Ne and the cross sections were found to be 10 to 100 times smaller than the single-capture cross sections. Measured two-electron loss cross sections for Ca/sup q + / ions incident on H 2 vary with charge state and depend strongly on whether L- or K-shell electrons are removed. Measurements of simultaneous projectile excitation and electron loss for several collision systems indicate that K-vacancy production occurs primarily through excitation rather than loss of the 1s electron. 13 refs

Fragmentation of high-energy ionic hydrogen clusters by single collision with helium

International Nuclear Information System (INIS)

Ouaskit, S.; Farizon, B.; Farizon, M.; Gaillard, M.J.; Chevarier, A.; Chevarier, N.; Gerlic, E.; Stern, M.

1994-09-01

Fragmentation of mass-selected 60-keV/amu-H n + induced by single collision with helium has been studied for various cluster sizes n (9, 13,21, 25, and 31). The absolute cross sections of the charged fragments H p + are measured from p equal to n-2. The deduced mass distributions are strongly different from those obtained at lower collision energy (where molecular evaporation is mainly involved) due to a strong production of ionic fragments with a size of p/n -τ , where A is the normalized fragment mass (p/n) and τ an exponent close to 2.6. (authors)

Basins in ARC-continental collisions

Science.gov (United States)

Draut, Amy E.; Clift, Peter D.; Busby, Cathy; Azor, Antonio

2012-01-01

Arc-continent collisions occur commonly in the plate-tectonic cycle and result in rapidly formed and rapidly collapsing orogens, often spanning just 5-15 My. Growth of continental masses through arc-continent collision is widely thought to be a major process governing the structural and geochemical evolution of the continental crust over geologic time. Collisions of intra-oceanic arcs with passive continental margins (a situation in which the arc, on the upper plate, faces the continent) involve a substantially different geometry than collisions of intra-oceanic arcs with active continental margins (a situation requiring more than one convergence zone and in which the arc, on the lower plate, backs into the continent), with variable preservation potential for basins in each case. Substantial differences also occur between trench and forearc evolution in tectonically erosive versus tectonically accreting margins, both before and after collision. We examine the evolution of trenches, trench-slope basins, forearc basins, intra-arc basins, and backarc basins during arc-continent collision. The preservation potential of trench-slope basins is low; in collision they are rapidly uplifted and eroded, and at erosive margins they are progressively destroyed by subduction erosion. Post-collisional preservation of trench sediment and trench-slope basins is biased toward margins that were tectonically accreting for a substantial length of time before collision. Forearc basins in erosive margins are usually floored by strong lithosphere and may survive collision with a passive margin, sometimes continuing sedimentation throughout collision and orogeny. The low flexural rigidity of intra-arc basins makes them deep and, if preserved, potentially long records of arc and collisional tectonism. Backarc basins, in contrast, are typically subducted and their sediment either lost or preserved only as fragments in melange sequences. A substantial proportion of the sediment derived from

High efficiency atomic hydrogen source

International Nuclear Information System (INIS)

Lagomarsino, V.; Bassi, D.; Bertok, E.; De Paz, M.; Tommasini, F.

1974-01-01

This work presents preliminary results of research intended to produce a M.W. discharge atomic hydrogen source with good dissociation at pressures larger than 10 torr. Analysis of the recombination process at these pressures shows that the volume recombination by three body collisions may be more important than wall recombination or loss of atoms by diffusion and flow outside the discharge region

Carbon Dioxide Hydrogenation into Higher Hydrocarbons and Oxygenates: Thermodynamic and Kinetic Bounds and Progress with Heterogeneous and Homogeneous Catalysis.

Science.gov (United States)

Prieto, Gonzalo

2017-03-22

Under specific scenarios, the catalytic hydrogenation of CO 2 with renewable hydrogen is considered a suitable route for the chemical recycling of this environmentally harmful and chemically refractory molecule into added-value energy carriers and chemicals. The hydrogenation of CO 2 into C 1 products, such as methane and methanol, can be achieved with high selectivities towards the corresponding hydrogenation product. More challenging, however, is the selective production of high (C 2+ ) hydrocarbons and oxygenates. These products are desired as energy vectors, owing to their higher volumetric energy density and compatibility with the current fuel infrastructure than C 1 compounds, and as entry platform chemicals for existing value chains. The major challenge is the optimal integration of catalytic functionalities for both reductive and chain-growth steps. This Minireview summarizes the progress achieved towards the hydrogenation of CO 2 to C 2+ hydrocarbons and oxygenates, covering both solid and molecular catalysts and processes in the gas and liquid phases. Mechanistic aspects are discussed with emphasis on intrinsic kinetic limitations, in some cases inevitably linked to thermodynamic bounds through the concomitant reverse water-gas-shift reaction, which should be considered in the development of advanced catalysts and processes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

State-to-state dynamics of H+HX collisions. II. The H+HX→HX/sup dagger/+H (X = Cl,Br,I) reactive exchange and inelastic collisions at 1.6 eV collision energy

International Nuclear Information System (INIS)

Aker, P.M.; Germann, G.J.; Tabor, K.D.; Valentini, J.J.

1989-01-01

We report measurement of product state distributions for the rotationally and/or vibrationally excited HX formed in collisions of translationally hot H atoms with HX (X = Cl, Br, and I) at 1.6 eV collision energy. The product state distributions are probed after only one collision of the fast H atom, using coherent anti-Stokes Raman scattering spectroscopy. Whether proceeding by inelastic collisions or reactive exchange, the transfer of translational energy to vibrational and rotational energy is quite inefficient in H+HX collisions at 1.6 eV. For all three hydrogen halides only 2--3% of the initial translational energy appears as HX vibration. For H+HCl only 6% of the initial energy is converted to HCl rotational energy, while for H+HBr and H+HI, this percentage is twice as large, 11--12%, but still small. The indistinguishability of the two H atoms involved makes it impossible to distinguish reactive exchange from inelastic energy transfer in these H+HX collisions. However, the difference in rotational energy partitioning for H+HBr and H+HI as compared with H+HCl, suggests that reactive exchange is dominant in the former and inelastic energy transfer dominates in the latter. The total cross sections for the combined energy transfer/reactive exchange do not change much with the identity of X, being 13 +- 3, 11 +- 2, and 11 +- 2 A 2 , for H+HCl, H+HBr, and H+HI, respectively

Quantum control of quasi-collision states: A protocol for hybrid fusion

Science.gov (United States)

Vilela Mendes, R.

2018-04-01

When confined to small regions quantum systems exhibit electronic and structural properties different from their free space behavior. These properties are of interest, for example, for molecular insertion, hydrogen storage and the exploration of new pathways for chemical and nuclear reactions. Here, a confined three-body problem is studied, with emphasis on the study of the “quantum scars” associated to dynamical collisions. For the particular case of nuclear reactions, it is proposed that a molecular cage might simply be used as a confining device with the collision states accessed by quantum control techniques.

Microwave interaction with nonuniform hydrogen gas in carbon nanotubes

International Nuclear Information System (INIS)

Babaei, S.; Babaei, Sh.

2009-01-01

In this paper we study the reflection, absorption, and transmission of microwave from nonuniform hydrogen gas in carbon nanotubes, grown by iron-catalyzed high-pressure carbon monoxide disproportionate (HiPco) process. A discussion on the effect of various hydrogen gas parameters on the reflected power, absorbed power, and transmitted power is presented. The nonuniform hydrogen gas slab is modeled by a series of subslabs. The overall number density profile across the whole slab follows a parabolic function. The total reflected, absorbed, and transmitted powers are then deduced and their functional dependence on the number density, collision frequency, and angle of propagation is studied

Pion correlations and calorimeter design for high energy heavy ion collisions. Progress report

International Nuclear Information System (INIS)

Wolf, K.L.

1997-01-01

Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV 208 Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered 208 Pb + Pb collisions. An updated multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au + Au reaction, taken with full event characterization

Theoretical study of non reactive collisions between alkaline atoms and hydrogen or deuterium molecules. Calculations and analysis of the potential surfaces. Application to the fine structure transitions of the Rubidium

International Nuclear Information System (INIS)

Rossi, F.N.

1986-10-01

The adiabatic potential lines are first obtained through the use of a pseudo-potential, depending on the electronic orbital moment. A perturbative method is then used to generate the potential surfaces, according to the potential lines. A quantum calculation in the thermal energy domain is realized, for the cross-sections concerning the structure transitions of the Rubidium, induced by the collision with hydrogen or deuterium molecules. This allowed the interpretation of the experimentally observed isotopic effect [fr

Hydrogen production by Cyanobacteria

Directory of Open Access Journals (Sweden)

Chaudhuri Surabhi

2005-12-01

Full Text Available Abstract The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical, Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

Progress on first-principles-based materials design for hydrogen storage.

Science.gov (United States)

Park, Noejung; Choi, Keunsu; Hwang, Jeongwoon; Kim, Dong Wook; Kim, Dong Ok; Ihm, Jisoon

2012-12-04

This article briefly summarizes the research activities in the field of hydrogen storage in sorbent materials and reports our recent works and future directions for the design of such materials. Distinct features of sorption-based hydrogen storage methods are described compared with metal hydrides and complex chemical hydrides. We classify the studies of hydrogen sorbent materials in terms of two key technical issues: (i) constructing stable framework structures with high porosity, and (ii) increasing the binding affinity of hydrogen molecules to surfaces beyond the usual van der Waals interaction. The recent development of reticular chemistry is summarized as a means for addressing the first issue. Theoretical studies focus mainly on the second issue and can be grouped into three classes according to the underlying interaction mechanism: electrostatic interactions based on alkaline cations, Kubas interactions with open transition metals, and orbital interactions involving Ca and other nontransitional metals. Hierarchical computational methods to enable the theoretical predictions are explained, from ab initio studies to molecular dynamics simulations using force field parameters. We also discuss the actual delivery amount of stored hydrogen, which depends on the charging and discharging conditions. The usefulness and practical significance of the hydrogen spillover mechanism in increasing the storage capacity are presented as well.

Electron and molecular ion collisions relevant to divertor plasma

International Nuclear Information System (INIS)

Takagi, H.

2005-01-01

We introduce the concept of the multi-channel quantum defect theory (MQDT) and show the outline of the MQDT newly extended to include the dissociative states. We investigate some molecular processes relevant to the divertor plasma by using the MQDT: the dissociative recombination, dissociative excitation, and rotation-vibrational transition in the hydrogen molecular ion and electron collisions. (author)

Collisions of carbon and oxygen ions with electrons, H, H2 and He: Volume 5

International Nuclear Information System (INIS)

Phaneuf, R.A.; Janev, R.K.; Pindzola, M.S.

1987-02-01

This report provides a handbook for fusion research of recommended cross-section and rate-coefficient data for collisions of carbon and oxygen ions with electrons, hydrogen atoms and molecules, and helium atoms. Published experimental and theoretical data have been collected and evaluated, and recommended data are presented in tabular, graphical, and parametrized form. Processes considered include exciation, ionization, and charge exchange at collision energies appropriate to applications in fusion-energy research

Progress of highly charged atomic physics at IMP

International Nuclear Information System (INIS)

Ma, X; Zhu, X L; Liu, H P; Li, B; Wei, B R; Sha, S; Cao, S P; Chen, L F; Zhang, S F; Feng, W T; Zhang, D C; Qian, D B

2007-01-01

The progress of atomic physics researches at the Institute of Modern Physics (IMP) is reviewed, covering the studies on ion-atom/molecule collisions, ion-cluster interaction, negative ion formation, state-selective electron capture studied by COLTRIMS, as well as the progress of a new experimental area dedicated for atomic researches at moderate energies, and the advances of the cooler storage rings at the Heavy Ion Research Facility in Lanzhou (HIRFL). New opportunities to study collision dynamics from femto-second to atto-second regime are opened based on the present facilities and the on-going projects

Multiple H3+ fragment production in single collision of fast Hn+ clusters with He atoms

International Nuclear Information System (INIS)

Farizon, B.; Farizon, M.; Gaillard, M.J.; Gerlic, E.; Ouaskit, S.

1994-09-01

The production of H 3 + ions resulting from single collisions of mass-selected ionic hydrogen clusters, H n + (n=9,25,31), with helium at high velocity (1.55 times the Bohr velocity) has been studied. A strong double H 3 + ion production resulting from one incident cluster is observed. Moreover, evidence for a triple H 3 + fragment production is presented for n=25 and 31. Thus, in this energy range, the collision gives rise to multifragmentation processes. The formation of H 3 + ions takes place in the fragmentation of the multicharged cluster resulting from the collision. (authors)

Two-electron excitation to Rydberg levels in fast I6+ on hydrogen collisions

International Nuclear Information System (INIS)

Liao, C.; Hagmann, S.; Zouros, T.J.M.; Montenegro, E.C.; Toth, G.; Richard, P.; Grabbe, S.; Bhalla, C.P.

1995-01-01

The emission of electrons in the forward direction in collisions of 0.3 MeV/u I 6+ with H 2 has been studied, and strong autoionization peaks are observed on the shoulder of the cusp peak. The energies of these autoionization lines in the projectile rest frame are determined by high-resolution electron spectroscopy. Using the electron projectile final charge state coincidence technique, we probe different collision mechanisms, which create continuum electrons that are slow in the projectile rest frame. We conclude that the observed autoionization lines are due to two electron excitation to projectile Rydberg levels. (orig.)

New directions in the theory of spin-polarized atomic hydrogen and deuterium

International Nuclear Information System (INIS)

Koelman, J.M.V.A.

1988-01-01

The three chapters of this thesis dealing with collisions between hydrogen (or deuterium) atoms in their ground state, each treat a different development in the theory of atomic hydrogen or deuterium gas. The decay due to interatomic collisions hindered till now all attempts to reach the low temperature, high-density regime where effects due to degeneracy are expected to show up. In ch. 2 a simple way out is presented for the case of Fermi gases: In spin-polarized Fermi systems at very low temperatures collisions are much effective than in Bose systems. For the Fermi gas, consisting of magnetically confined deuterium atoms, it appears that fast spin-exchange collisions automatically lead to a completely spin-polarized gas for which the spin-relaxation limited lifetime increases dramatically with decreasing temperature. As also the ratio of internal thermalization rate over decay rate increases with decreasing temperature, this gas can be cooled by forced evaporation down to very low temperatures. In ch. 3 it iis shown that the nuclear spin dynamics due to the hyperfine interaction during collisions, strongly limits the improvement in frequency stability attainable by H masers operating at low temperatures. In ch. 4 the phenomenon of spin waves is studied. It is shown that, despite the fact that interactions between two atoms are nuclear-spin independent, the outcome of a scattering event does not depend on the nuclear spins involved due to the particle indistinguishability effects at low collision energies. This effect gives rise to quantum phenomena on a macroscopic scale via the occurrence of spin waves. (author). 185 refs.; 34 figs

Inelastic molecular collisions: application of theoretical methods to problems relevant to laser operation. Progress report, February 1, 1976--November 1, 1976. [Summary of research activities at Princeton Univ

Energy Technology Data Exchange (ETDEWEB)

Rabitz, H

1976-01-01

The main goals of this research are to develop and implement various techniques for describing molecular collision phenomena. The aim is to achieve sufficient understanding of these processes such that collision rates of interest (e.g., for gas lasers) may be reliably estimated. Several areas of research are being explored to achieve this goal. The specific molecular systems of H/sub 2/-H/sub 2/, HF-He, HF-Ar and HCl-Ar are being studied as examples of inelastic molecular collisions. In addition, during the past year further theoretical development was conducted in the area of decomposition techniques and effective Hamiltonian theory. Considerable progress was made in these various areas during the past year. This research represents a collaboration under this contract and with Professor R. Conn, University of Wisconsin, under contract AT(11-1)-2555. Much of the material in this report has been published or is presently in press (items indicated by * in the references).

Radiation from heavy ion collisions

International Nuclear Information System (INIS)

Kast, J.R.; Lee, Y.K.

1975-01-01

A study of x rays produced in heavy ion collisions has led to a search for molecular orbital x rays, concentrating on 35 Cl ions on Al, NaCl, and C targets. Preliminary analysis of the angular dependence of continuum x rays has tentatively identified quasi-molecular K x rays. Other work completed and in progress is discussed. (3 figures) (U.S.)

Towards high-density matter with relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Nagamiya, Shoji.

1990-04-01

Recent progress in nucleus-nucleus collisions at BNL and CERN suggests a hint that the formation of high-density nuclear matter could be possible with relativistic heavy-ion beams. What is the maximum density that can be achieved by heavy-ion collisions? Are there data which show evidence or hints on the formation of high density matter? Why is the research of high-density interesting? How about the future possibilities on this subject? These points are discussed. (author)

Collisional destruction of fast hydrogen Rydberg atoms

International Nuclear Information System (INIS)

King, M.R.

1984-01-01

A new modulated electric field technique was developed to study Rydberg atom destruction processes in a fast beam. The process of destruction of a band of Rydberg atom destruction of a band of Rydberg atoms through the combined processes of ionization, excitation, and deexcitation was studied for collisions with gas targets. Rydberg atoms of hydrogen were formed by electron capture, and detected by field ionization. The modulated field technique described proved to be an effective technique for producing a large signal for accurate cross section measurements. The independent particle model for Rydberg atom destruction processes was found to hold well for collisions with molecular nitrogen, argon, and carbon dioxide. The resonances in the cross sections for the free electron scattering with these targets were found to also occur in Rydberg destruction. Suggestions for future investigations of Rydberg atom collision processes in the fast beam regime are given

Asymptotic form of the charge-exchange cross section in three-body rearrangement collisions

Science.gov (United States)

Omidvar, K.

1975-01-01

A three-body general-type rearrangement collision is considered in which the initial and final bound states are described by hydrogen-like wave functions. It is shown that the charge-exchange amplitude in the first Born approximation can be expanded at all incident energies in terms of the inverse powers of the principal quantum number (n). By expanding the exchange amplitude in this way, it is demonstrated conclusively that the cross section for capture into the s, p, and d states as well as for the sum over all the angular-momentum states is proportional to 1/n-cubed plus terms proportional to higher inverse odd powers of n. It is found that the low-lying levels cannot be scaled to the 1/n-cubed law irrespective of the value of the incident energy except in the case of capture into the s states in accordance with the Oppenheimer-Brinkman-Kramers approximation. Zeros and minima in the differential cross sections are given in the limit of high principal quantum number for electron capture by protons from atomic hydrogen and for positronium formation by proton-atomic hydrogen collisions.

Storing Hydrogen, by Enhancing Diamond Powder Properties under Hydrogen Plasma with CaF2 and KF for Use in Fuel Cells

International Nuclear Information System (INIS)

Ochoa, Franklyn E. Colmenares

2006-01-01

A fuel cell is like a battery that instead of using electricity to recharge itself, it uses hydrogen. In the fuel cell industry, one of the main problems is storing hydrogen in a safe way and extracting it economically. Gaseous hydrogen requires high pressures which could be very dangerous in case of a collision. The success of hydrogen use depends largely on the development of an efficient storage and release method. In an effort to develop a better hydrogen storage system for fuel cells technology this research investigates the use of 99% pure diamond powder for storing hydrogen. Mixing this powder with a calcium fluoride and potassium fluoride compound in its solid form and treating the surface of the powder with hydrogen plasma, modifies the surface of the diamond. After some filtration through distilled water and drying, the modified diamond is treated with hydrogen. We expect hydrogen to be attracted to the diamond powder surface in higher quantities due to the CaF2 and KF treatment. Due to the large surface area of diamond nanopowder and the electronegative terminal bonds of the fluorine particles on the structure's surface, to the method shows promise in storing high densities of hydrogen

Cyanobacterial Hydrogenases and Hydrogen Metabolism Revisited: Recent Progress and Future Prospects

Directory of Open Access Journals (Sweden)

Namita Khanna

2015-05-01

Full Text Available Cyanobacteria have garnered interest as potential cell factories for hydrogen production. In conjunction with photosynthesis, these organisms can utilize inexpensive inorganic substrates and solar energy for simultaneous biosynthesis and hydrogen evolution. However, the hydrogen yield associated with these organisms remains far too low to compete with the existing chemical processes. Our limited understanding of the cellular hydrogen production pathway is a primary setback in the potential scale-up of this process. In this regard, the present review discusses the recent insight around ferredoxin/flavodoxin as the likely electron donor to the bidirectional Hox hydrogenase instead of the generally accepted NAD(PH. This may have far reaching implications in powering solar driven hydrogen production. However, it is evident that a successful hydrogen-producing candidate would likely integrate enzymatic traits from different species. Engineering the [NiFe] hydrogenases for optimal catalytic efficiency or expression of a high turnover [FeFe] hydrogenase in these photo-autotrophs may facilitate the development of strains to reach target levels of biohydrogen production in cyanobacteria. The fundamental advancements achieved in these fields are also summarized in this review.

Theory of collective dynamics: flow, fluctuations and correlations in heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

Denicol, Gabriel S. [Physics Department, Brookhaven National Lab, Building 510A, Upton, NY, 11973 (United States); Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada)

2016-12-15

I review recent developments in the hydrodynamic modeling of ultra-relativistic heavy ion collisions and the extraction of the properties of bulk QCD matter from heavy ion collision measurements. I briefly summarize the current framework used for the theoretical modeling of heavy ion collisions and report the recent progress on the extraction of the temperature dependence of the shear and bulk viscosity coefficients, the development of statistical tools for data-to-model comparison, and anisotropic hydrodynamics. All these recent developments in our field pave the way for more quantitative determination of the transport properties of bulk QCD matter from the experimental heavy ion collision program.

Collision Risk and Damage after Collision

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Hansen, Peter Friis; Nielsen, Lars Peter

1996-01-01

The paper presents a new and complete procedure for calculation of ship-ship collision rates on specific routes and the hull damage caused by such collisions.The procedure is applied to analysis of collision risks for Ro-Ro pasenger vessels. Given a collision the spatial probability distribution ...

Electron-hydrogen atom inelastic scattering through a correlated wave function

International Nuclear Information System (INIS)

Serpa Vieira, A.E. de.

1984-01-01

The inelastic collision between an electron and a hydrogen atom is studied. A correlated function, used previously to the same system in elastic collisions in which there are two parameters fitted in the energy range studied, is utilized. With this functions an equation is developed for the direct and exchange transition matrix elements to the 15-25 and 15-2 p transitions. The obtained results are compared with Willians experimental measurements, as well the results given by the theoretical treatments of Kingston, Fon and Burke. (L.C.) [pt

Hydrogen release from irradiated elastomers measured by Nuclear Reaction Analysis

Energy Technology Data Exchange (ETDEWEB)

Jagielski, J., E-mail: jacek.jagielski@itme.edu.pl [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); National Centre for Nuclear Research, A. Soltana 7, 05-400 Swierk/Otwock (Poland); Ostaszewska, U. [Institute for Engineering of Polymer Materials & Dyes, Division of Elastomers & Rubber Technology, Harcerska 30, 05-820 Piastow (Poland); Bielinski, D.M. [Technical University of Lodz, Institute of Polymer & Dye Technology, Stefanowskiego 12/16, 90-924 Lodz (Poland); Grambole, D. [Institute of Ion Beam Physics and Materials Research, Helmholtz Zentrum Dresden Rossendorf, PO Box 51 01 19, D-01314 Dresden (Germany); Romaniec, M.; Jozwik, I.; Kozinski, R. [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); Kosinska, A. [National Centre for Nuclear Research, A. Soltana 7, 05-400 Swierk/Otwock (Poland)

2016-03-15

Ion irradiation appears as an interesting method of modification of elastomers, especially friction and wear properties. Main structural effect caused by heavy ions is a massive loss of hydrogen from the surface layer leading to its smoothening and shrinking. The paper presents the results of hydrogen release from various elastomers upon irradiation with H{sup +}, He{sup +} and Ar{sup +} studied by using Nuclear Reaction Analysis (NRA) method. The analysis of the experimental data indicates that the hydrogen release is controlled by inelastic collisions between ions and target electrons. The last part of the study was focused on preliminary analysis of mechanical properties of irradiated rubbers.

Development of an in-vehicle intersection collision countermeasure

Science.gov (United States)

Pierowicz, John A.

1997-02-01

Intersection collisions constitute approximately twenty-six percent of all accidents in the United States. Because of their complexity, and demands on the perceptual and decision making abilities of the driver, intersections present an increased risk of collisions between automobiles. This situation provides an opportunity to apply advanced sensor and processing capabilities to prevent these collisions. A program to determine the characteristics of intersection collisions and identify potential countermeasures will be described. This program, sponsored by the National Highway Traffic Safety Administration, utilized accident data to develop a taxonomy of intersection crashes. This taxonomy was used to develop a concept for an intersection collision avoidance countermeasure. The concept utilizes in-vehicle position, dynamic status, and millimeter wave radar system and an in-vehicle computer system to provide inputs to an intersection collision avoidance algorithm. Detection of potential violation of traffic control device, or proceeding into the intersection with inadequate gap will lead to the presentation of a warning to the driver. These warnings are presented to the driver primarily via a head-up display and haptic feedback. Roadside to vehicle communication provides information regarding phased traffic signal information. Active control of the vehicle's brake and steering systems are described. Progress in the development of the systems will be presented along with the schedule of future activities.

Proceedings of the 1999 U.S. DOE Hydrogen Program Review

Energy Technology Data Exchange (ETDEWEB)

NREL

2000-08-28

The Proceedings of the 1999 US Department of Energy (DOE) Hydrogen Program Review serve as an important technology reference for the DOE Hydrogen Program. This document contains technical progress reports on 60 research and technology validation projects funded by the DOE Hydrogen Program in Fiscal Year 1999, in support of its mission to make hydrogen a cost-effective energy carrier for utility, building, and transportation applications. Each year, the Program conducts a rigorous review of its portfolio of projects, utilizing teams of experts to provide vital feedback on the progress of research.

Double electron capture by protons in collisions with H2

International Nuclear Information System (INIS)

Salazar-Zepeda, M.H.; Gleason, Cristian; Gonzalez, Eduardo; Gonzalez-Magana, O.; Hinojosa, Guillermo

2010-01-01

Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H - velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.

Orientation and alignment in H+-H collisions

International Nuclear Information System (INIS)

Hansen, J.P.; Dubois, A.; Nielsen, S.E.

1991-01-01

We have calculated probabilities, orientation parameters, and alignment angles for 2p excitation and capture in proton-hydrogen collisions at 50- and 100-keV projectile energy. The results, obtained from solving the Schroedinger equation in a multistate atomic-orbital expansion, are compared to those of a similar, recently published investigation. In both studies, similar results for excitation are found, and also for capture at large impact parameters. The origin of different predictions for capture at intermediate impact parameters is discussed

Study of mechanism of hydrogen diffusion in separation devices. Progress report for 1980-1983

International Nuclear Information System (INIS)

Lee, M.H.

1983-01-01

For the purpose of studying the mechanisms of hydrogen diffusion in separation devices e.g. transition-metal membranes, we have developed a microscopic dynamic model appropriate for describing the nonequilibrium statistical mechanics of hydrogen-in-a-metal. Using this model we have carried out a detailed analysis to obtain the autocorrelation function of density fluctuations in the model. Our model is built on the physical idea that, at low temperatures, spin clusters are the basic units or aggregates of transport. Our work can explain the reversed isotope effect in diffusion. We have also obtained an expression for the relative diffusivity, verifiable by experiments with tritium in metals. Our notion of spin clusters is novel. There is some evidence of their existence. The interstitial spin clusters are comparable to atomic and nuclear spin clusters, the only other natural spin clusters. Our demonstration of a long-time tail in the autocorrelation function is also novel. Diffusion can be anomalous if long time tails exist, a current topic in nonlinear behavior of fluids and solids. Our progress has been made possible by our development in the mathematical method of solving the generalized Langevin equation. This method is applicable to any time-dependent quantum many-body model. The underlying basis of this method is our discovery of a new orthogonalization process in Hilbert space, first since Gram and Schmidt over 100 years ago. Our process is simpler if Hilbert space is realized as is for all physical problems. To demonstrate the power and utility of our method we considered a well established model of metals, thereby discovering the existence of a low-frequency electronic mobility. This kind of intrinsic conductivity should exist in ensembles of all light particles, hence also relevant to hydrogen and its isotopes in metals

Studies of fluctuation processes in nuclear collisions

International Nuclear Information System (INIS)

Ayik, S.

1991-02-01

This report summarizes the progress on grant No. DE-FG05-89ER40530 during the period April 15, 1990 to February 15, 1991. Our studies of heavy-ion collisions in the framework of ''a stochastic one-body transport model'' has progress in several directions. We developed a method for obtaining approximate numerical solutions of the transport-equation in semi-classical limit, i.e., Boltzmann-Langevin equation, and tested the method in realistic cases of heavy-ion collisions at energies below 100 MeV per nucleon. Some results of the numerical simulations for a head-on collision of 12 C + 12 C system is included in this report. Work has also continued on studying the stochastic one-body transport model in a quantal representation, which provides a microscopic basis for a consistent description of dissipation and fluctuation properties of large amplitude collective nuclear motion. The previous derivation of the stochastic one-body transport model was presented within the density matrix formalisam. We generalized this treatment and proposed an alternative derivation of the model by employing the Green's function approach within the real-time path formalism of Keldish. One manuscript has been submitted to Nucl. Phys. A for publication. Two other manuscripts are in preparation for publication. Several seminars and contributed talks were presented at various meeting

Computational Laboratory Astrophysics to Enable Transport Modeling of Protons and Hydrogen in Stellar Winds, the ISM, and other Astrophysical Environments

Science.gov (United States)

Schultz, David

As recognized prominently by the APRA program, interpretation of NASA astrophysical mission observations requires significant products of laboratory astrophysics, for example, spectral lines and transition probabilities, electron-, proton-, or heavy-particle collision data. Availability of these data underpin robust and validated models of astrophysical emissions and absorptions, energy, momentum, and particle transport, dynamics, and reactions. Therefore, measured or computationally derived, analyzed, and readily available laboratory astrophysics data significantly enhances the scientific return on NASA missions such as HST, Spitzer, and JWST. In the present work a comprehensive set of data will be developed for the ubiquitous proton-hydrogen and hydrogen-hydrogen collisions in astrophysical environments including ISM shocks, supernova remnants and bubbles, HI clouds, young stellar objects, and winds within stellar spheres, covering the necessary wide range of energy- and charge-changing channels, collision energies, and most relevant scattering parameters. In addition, building on preliminary work, a transport and reaction simulation will be developed incorporating the elastic and inelastic collision data collected and produced. The work will build upon significant previous efforts of the principal investigators and collaborators, will result in a comprehensive data set required for modeling these environments and interpreting NASA astrophysical mission observations, and will benefit from feedback from collaborators who are active users of the work proposed.

Vibrational and cascade dissociation of H{sub 2}{sup +} ions by collision with gas molecules; Dissociation vibrationnelle et dissociation en cascade d'ions H{sub 2}{sup +} par collisions avec les molecules d'un gaz

Energy Technology Data Exchange (ETDEWEB)

Verveer, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-07-01

Protons produced by collisional dissociation of H{sub 2}{sup +} ions have an energy spectrum with a narrow central peak. For a part the protons in this peak are produced by vibrational dissociation and for another part by a cascade of two collisions. For H{sub 2}{sup +} ions of 50 to 150 keV the cross section for vibrational dissociation is about 4.1 10{sup -19} cm{sup 2}/molecule in hydrogen and 1.1 10{sup -18} cm{sup 2}/molecule in argon. (author) [French] Les protons resultant de la dissociation par collisions d'ions H{sub 2}{sup +} dans un gaz ont un spectre d'energie qui presente un pic central tres etroit. Les protons dans ce pic proviennent, pour une part de la dissociation vibrationnelle et pour l'autre part d'une suite de deux collisions. Dans le domaine d'energie des ions H{sub 2}{sup +} de 50 a 150 keV la section efficace de dissociation vibrationnel vaut 4.1 10{sup -19} cm{sup 2}/molecule pour l'hydrogene et 1,1 10{sup -18} cm{sup 2}/molecule pour l'argon.

Measurements of scattering processes in negative ion-atom collisions

International Nuclear Information System (INIS)

Kvale, T.J.

1991-01-01

This research project is designed to provide measurements of various scattering processes which occur in H - collisions with atomic targets at intermediate energies. The immediate goal is to study elastic scattering, single electron detachment, and target excitation/ionization in H - scattering from noble gas targets. For the target inelastic processes, these cross sections are unknown both experimentally and theoretically. The present measurements will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion collisions. This series of experiments required the construction of a new facility, and significant progress toward its operation has been realized during this period. The proposed research is described in this report. The progress on and the status of the apparatus is also detailed in this report

Theoretical interpretation of data from high-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1988-09-01

Nuclear collision data at energies ranging from medium to relativistic are interpreted theoretically. The major objective is a better understanding of high-energy heavy-ion collisions, with particular emphasis on the properties of excited nuclear matter. Further progress towards a satisfactory description of excited subsaturation nuclear matter is achieved. The mean free path of a nucleon in nuclear matter, which is a critical parameter in assessing the applicability of certain nuclear collision models, is investigated. Experimental information is used together with theoretical concepts in collaborations with experimentalists in order to learn about the reaction mechanism and about excited nuclear matter properties. In the framework of a more strictly theoretical program development, subnuclear degrees of freedom and nonlinear phenomena in model field theories are studied

Future directions in electron--ion collision physics

International Nuclear Information System (INIS)

Reed, K.J.; Griffin, D.C.

1992-01-01

This report discusses the following topics: Summary of session on synergistic co-ordination of theory and experiment; synergism between experiment and theory in atomic physics; comparison of theory and experiment for electron-ion excitation and ionization; summary of session on new theoretical and computational methods; new theoretical and computational methods-r-matrix calculations; the coulomb three-body problem: a progress report; summary of session on needs and applications for electron-ion collisional data; electron-ion collisions in the plasma edge; needs and applications of theoretical data for electron impact excitation; summary of session on relativistic effects, indirect effects, resonance, etc; direct and resonant processes in electron-ion collisions; relativistic calculations of electron impact ionization and dielectronic recombination cross section for highly charged ions; electron-ion recombination in the close-coupling approximation; modified resonance amplitudes with strongly correlated channels; a density-matrix approach to the broadening of spectral lines by autoionization, radiative transitions and electron-ion collisions; towards a time-dependent description of electron-atom/ion collisions two electron systems; and comments on inclusion of the generalized bright interaction in electron impact excitation of highly charged ions

Hydrogen as automotive fuel

International Nuclear Information System (INIS)

Ambrosini, G.; Ciancia, A.; Pede, G.; Brighigna, M.

1993-01-01

Hydrogen fueled vehicles may just be the answer to the air pollution problem in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives. This paper examines the feasibility of hydrogen as an automotive fuel by analyzing the following aspects: the chemical-physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems; current production technologies and commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. With reference to recent trial results being obtained in the USA, an assessment is also made of the feasibility of the use of methane-hydrogen mixtures as automotive fuels. The paper concludes with a review of progress being made by ENEA (the Italian Agency for New Technology, Energy and the Environment) in the development of fuel storage and electronic fuel injection systems for hydrogen powered vehicles

Interference between vibration-to-translation and vibration-to-vibration energy transfer modes in diatomic molecules at high collision energies

International Nuclear Information System (INIS)

Shin, H.K.

1983-01-01

An explicit time dependent approach for simultaneous VT and VV energy transfer in diatom--diatom collisions is explored using the exponential form of ladder operators in the solution of the Schroedinger equation of motion. The collision of two hydrogen molecules is chosen to illustrate the extent of interference between VT and VV modes among various vibrational states. While vibrational energy transfer processes of nominally VT type can be treated with pure VT mode at low collision energies, the intermode coupling is found to be very important at collision energies of several hω. The occurrence of the coupling appears to be nearly universal in vibrational transitions at such energies. Exceptions to the coupling have been discussed

Ekpyrosis and inflationary dynamics in heavy ion collisions: the role of quantum fluctuations

Energy Technology Data Exchange (ETDEWEB)

Dusling, K.; Venugopalan, R.; Gelis, F.

2011-05-23

We summarize recent significant progress in the development of a first-principles formalism to describe the formation and evolution of matter in very high energy heavy ion collisions. The key role of quantum fluctuations both before and after a collision is emphasized. Systematic computations are now feasible to address early time isotropization, flow, parton energy loss and the Chiral Magnetic Effect.

Low energy cross section data for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions with atoms and molecules

International Nuclear Information System (INIS)

Okuno, Kazuhiko

2007-04-01

Systematic cross section measurements for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions in low energy collisions with atoms and molecules have been performed continuously by the identical apparatus installed with an octo-pole ion beam guide (OPIG) since 1980 till 2004. Recently, all of accumulated cross section data for a hundred collision systems has been entered into CMOL and CHART of the NIFS atomic and molecular numerical database together with some related cross section data. In this present paper, complicated ion-molecule reactions in hydrogen systems are revealed and the brief outlines of specific properties in low energy charge transfer collisions of multiply charged ions with atoms and molecules are introduced. (author)

Hydrogen perspectives in Japan

International Nuclear Information System (INIS)

Furutani, H.

2000-01-01

Hydrogen energy is considered to present a potential effective options for achieving the greenhouse gas minimization. The MITI (Ministry of International Trade and Industry) of Japanese Government is promoting the WE-NET (World Energy Network System) Project which envisions (1) construction of a global energy network for effective supply, transportation, storage and utilization of renewable energy using hydrogen as an energy carrier as a long-term options of sustainable energy economy, and (2) promotion of market entry of hydrogen energy in near and/or mid future even before construction of a WE-NET system. In this paper, I would like to report how far the hydrogen energy technology development addressed under Phase I has progressed, and describe the outline of the Phase II Plan. (author)

The theory of relativistic heavy ion collisions. [Annual] progress report, [July 1, 1993--June 30, 1994

International Nuclear Information System (INIS)

Shuryak, E.

1994-07-01

For clarity of presentation, we have divided the topics of interest into the following main topics which are discussed in this report: the dynamics of nuclear collisions at very high energies (RHIC and LHC); electromagnetic probes; the dynamics of nuclear collisions at AGS energies; and non-perturbative QCD and the physics of the phase transition

Theoretical research in intermediate-energy nuclear physics. [Technical progress report, April 1, 1993--March 31, 1994

International Nuclear Information System (INIS)

Seki, R.

1994-01-01

This paper discusses progress that has been made on the following seven problems: (1) (e, e'p) at high momentum transfer; (2) post,acceleration effects in two-nucleon interferometry of heavy-ion collisions; (3) pion-nucleus interactions above 0.5 GeV; (4) chiral symmetry breaking in nuclei and picnic atom anomaly; (5) atomic screening on nuclear astronomical reactions; (6) QCD related work (coherent pion production from skyrmion-antiskyrmion annihilation, QCD in 1 + 1 dimensions, and correlation functions in the QCD vacuum), and (7) kaonic hydrogen atom experiment. The problems deal with various topics mostly in intermediate-energy nuclear physics. We place priority on (1) and (2), and describe them somewhat in detail below. Other problems are our on-going projects, but we are placing lower priority on them in the second and third year

A Rechargeable Hydrogen Battery.

Science.gov (United States)

Christudas Dargily, Neethu; Thimmappa, Ravikumar; Manzoor Bhat, Zahid; Devendrachari, Mruthunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Gautam, Manu; Shafi, Shahid Pottachola; Thotiyl, Musthafa Ottakam

2018-04-27

We utilize proton-coupled electron transfer in hydrogen storage molecules to unlock a rechargeable battery chemistry based on the cleanest chemical energy carrier molecule, hydrogen. Electrochemical, spectroscopic, and spectroelectrochemical analyses evidence the participation of protons during charge-discharge chemistry and extended cycling. In an era of anthropogenic global climate change and paramount pollution, a battery concept based on a virtually nonpolluting energy carrier molecule demonstrates distinct progress in the sustainable energy landscape.

Single-collision studies of hot atom energy transfer and chemical reaction

International Nuclear Information System (INIS)

Valentini, J.J.

1991-01-01

This report discusses research in the collision dynamics of translationally hot atoms, with funding with DOE for the project ''Single-Collision Studies of Hot Atom Energy Transfer and Chemical Reaction,'' Grant Number DE-FG03-85ER13453. The work reported here was done during the period September 9, 1988 through October 31, 1991. During this period this DOE-funded work has been focused on several different efforts: (1) experimental studies of the state-to-state dynamics of the H + RH → H 2 R reactions where RH is CH 4 , C 2 H 6 , or C 3 H 8 , (2) theoretical (quasiclassical trajectory) studies of hot hydrogen atom collision dynamics, (3) the development of photochemical sources of translationally hot molecular free radicals and characterization of the high resolution CARS spectroscopy of molecular free radicals, (4) the implementation of stimulated Raman excitation (SRE) techniques for the preparation of vibrationally state-selected molecular reactants

Collision processes of hydrocarbon species in hydrogen plasmas. II The ethane and propane families

CERN Document Server

Janev, R K

2002-01-01

Cross sections and rate coefficients are provided for collision processes of electrons and protons with C sub x H sub y and C sub x H sub y sup + (x = 2, 3; 1 <= y <= 2x + 2) hydrocarbon species in a wide range of collision energies and plasma (gas) temperatures. The considered processes include: electron-impact ionization and dissociation of C sub x H sub y , dissociative excitation, ionization and recombination of C sub x H sub y sup + with electrons, and both charge transfer and atom exchange in proton channels are considered separately. Information is also provided for the energies of each individual reaction channel. The cross sections and rate coefficients are presented in compact analytic forms.

Multiregion, multigroup collision probability method with white boundary condition for light water reactor thermalization calculations

International Nuclear Information System (INIS)

Ozgener, B.; Ozgener, H.A.

2005-01-01

A multiregion, multigroup collision probability method with white boundary condition is developed for thermalization calculations of light water moderated reactors. Hydrogen scatterings are treated by Nelkin's kernel while scatterings from other nuclei are assumed to obey the free-gas scattering kernel. The isotropic return (white) boundary condition is applied directly by using the appropriate collision probabilities. Comparisons with alternate numerical methods show the validity of the present formulation. Comparisons with some experimental results indicate that the present formulation is capable of calculating disadvantage factors which are closer to the experimental results than alternative methods

Multiple-Vehicle Longitudinal Collision Mitigation by Coordinated Brake Control

Directory of Open Access Journals (Sweden)

Xiao-Yun Lu

2014-01-01

Full Text Available Rear-end collision often leads to serious casualties and traffic congestion. The consequences are even worse for multiple-vehicle collision. Many previous works focused on collision warning and avoidance strategies of two consecutive vehicles based on onboard sensor detection only. This paper proposes a centralized control strategy for multiple vehicles to minimize the impact of multiple-vehicle collision based on vehicle-to-vehicle communication technique. The system is defined as a coupled group of vehicles with wireless communication capability and short following distances. The safety relationship can be represented as lower bound limit on deceleration of the first vehicle and upper bound on maximum deceleration of the last vehicle. The objective is to determine the desired deceleration for each vehicle such that the total impact energy is minimized at each time step. The impact energy is defined as the relative kinetic energy between a consecutive pair of vehicles (approaching only. Model predictive control (MPC framework is used to formulate the problem to be constrained quadratic programming. Simulations show its effectiveness on collision mitigation. The developed algorithm has the potential to be used for progressive market penetration of connected vehicles in practice.

On the Collision Nature of Two Coronal Mass Ejections: A Review

Science.gov (United States)

Shen, Fang; Wang, Yuming; Shen, Chenglong; Feng, Xueshang

2017-08-01

Observational and numerical studies have shown that the kinematic characteristics of two or more coronal mass ejections (CMEs) may change significantly after a CME collision. The collision of CMEs can have a different nature, i.e. inelastic, elastic, and superelastic processes, depending on their initial kinematic characteristics. In this article, we first review the existing definitions of collision types including Newton's classical definition, the energy definition, Poisson's definition, and Stronge's definition, of which the first two were used in the studies of CME-CME collisions. Then, we review the recent research progresses on the nature of CME-CME collisions with the focus on which CME kinematic properties affect the collision nature. It is shown that observational analysis and numerical simulations can both yield an inelastic, perfectly inelastic, merging-like collision, or a high possibility of a superelastic collision. Meanwhile, previous studies based on a 3D collision picture suggested that a low approaching speed of two CMEs is favorable for a superelastic nature. Since CMEs are an expanding magnetized plasma structure, the CME collision process is quite complex, and we discuss this complexity. Moreover, the models used in both observational and numerical studies contain many limitations. All of the previous studies on collisions have not shown the separation of two colliding CMEs after a collision. Therefore the collision between CMEs cannot be considered as an ideal process in the context of a classical Newtonian definition. In addition, many factors are not considered in either observational analysis or numerical studies, e.g. CME-driven shocks and magnetic reconnections. Owing to the complexity of the CME collision process, a more detailed and in-depth observational analysis and simulation work are needed to fully understand the CME collision process.

Simultaneous purification and storage of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Hynek, S.; Fuller, W.; Weber, R.; Carlson, E. [Arthur D. Little, Inc., Cambridge, MA (United States)

1998-08-01

Specially coated magnesium particles have been shown to selectively absorb hydrogen from a hydrogen-rich gas stream such as reformate. These coated magnesium particles can store the absorbed hydrogen as required and subsequently deliver pure hydrogen, just as uncoated magnesium particles can. These coated magnesium particles could be used in a device that accepts a steady stream of reformate, as from a methane reformer, stores the selectively absorbed hydrogen indefinitely, and delivers purified hydrogen on demand. Unfortunately, this coating (magnesium nitride) has been shown to degrade over a period of several weeks, so that the magnesium within evidences progressively lower storage capacity. The authors are investigating two other coatings, one of which might be applicable to hydridable metals other than magnesium, to replace magnesium nitride.

Medium response to jets in heavy ion collisions

Science.gov (United States)

Tachibana, Yasuki

2018-01-01

A short overview on recent progress in studies of medium response to jet quenching in heavy ion collisions is presented. We show the typical features of medium response and give comment on their connection to jet observables by introducing the work done by the author and collaborators as an example.

Photoelectrochemical hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Rocheleau, R.E.; Miller, E.; Misra, A. [Univ. of Hawaii, Honolulu, HI (United States)

1996-10-01

The large-scale production of hydrogen utilizing energy provided by a renewable source to split water is one of the most ambitious long-term goals of the U.S. Department of Energy`s Hydrogen Program. One promising option to meet this goal is direct photoelectrolysis in which light absorbed by semiconductor-based photoelectrodes produces electrical power internally to split water into hydrogen and oxygen. Under this program, direct solar-to-chemical conversion efficiencies as high as 7.8 % have been demonstrated using low-cost, amorphous-silicon-based photoelectrodes. Detailed loss analysis models indicate that solar-to-chemical conversion greater than 10% can be achieved with amorphous-silicon-based structures optimized for hydrogen production. In this report, the authors describe the continuing progress in the development of thin-film catalytic/protective coatings, results of outdoor testing, and efforts to develop high efficiency, stable prototype systems.

Key challenges and recent progress in batteries, fuel cells, and hydrogen storage for clean energy systems

Science.gov (United States)

Chalk, Steven G.; Miller, James F.

Reducing or eliminating the dependency on petroleum of transportation systems is a major element of US energy research activities. Batteries are a key enabling technology for the development of clean, fuel-efficient vehicles and are key to making today's hybrid electric vehicles a success. Fuel cells are the key enabling technology for a future hydrogen economy and have the potential to revolutionize the way we power our nations, offering cleaner, more efficient alternatives to today's technology. Additionally fuel cells are significantly more energy efficient than combustion-based power generation technologies. Fuel cells are projected to have energy efficiency twice that of internal combustion engines. However before fuel cells can realize their potential, significant challenges remain. The two most important are cost and durability for both automotive and stationary applications. Recent electrocatalyst developments have shown that Pt alloy catalysts have increased activity and greater durability than Pt catalysts. The durability of conventional fluorocarbon membranes is improving, and hydrocarbon-based membranes have also shown promise of equaling the performance of fluorocarbon membranes at lower cost. Recent announcements have also provided indications that fuel cells can start from freezing conditions without significant deterioration. Hydrogen storage systems for vehicles are inadequate to meet customer driving range expectations (>300 miles or 500 km) without intrusion into vehicle cargo or passenger space. The United States Department of Energy has established three centers of Excellence for hydrogen storage materials development. The centers are focused on complex metal hydrides that can be regenerated onboard a vehicle, chemical hydrides that require off-board reprocessing, and carbon-based storage materials. Recent developments have shown progress toward the 2010 DOE targets. In addition DOE has established an independent storage material testing center

Measurements of the structure of an ionizing shock wave in a hydrogen-helium mixture.

Science.gov (United States)

Leibowitz, L. P.

1973-01-01

Shock structure during ionization of a hydrogen-helium mixture has been followed using hydrogen line and continuum emission measurements. A reaction scheme is proposed which includes hydrogen dissociation and a two-step excitation-ionization mechanism for hydrogen ionization by atom-atom and atom-electron collisions. Agreement has been achieved between numerical calculations and measurements of emission intensity as a function of time for shock velocities from 13 to 20 km/sec in a 0.208 H2-0.792 He mixture. The electron temperature was found to be significantly different from the heavy particle temperature during much of the ionization process. Similar time histories for H beta and continuum emission indicate upper level populations of hydrogen in equilibrium with the electron concentration during the relaxation process.

Recent results from the CELSIUS/WASA collaboration on meson production in proton-hydrogen collisions

International Nuclear Information System (INIS)

Bilger, R.; Bondar, A.; Brodowski, W.; Calen, H.; Clement, H.; Dyring, J.; Ekstroem, C.; Fransson, K.; Gustafsson, L.; Haeggstroem, S.; Hoeistad, B.; Johanson, J.; Johansson, A.; Johansson, T.; Kilian, K.; Kullander, S.; Kupsc, A.; Kuzmin, A.; Marciniewski, P.; Morosov, B.; Moertsell, A.; Oelert, W.; Povtorejko, A.; Ruber, R.J.M.Y.; Schuberth, U.; Sefzick, T.; Sidorov, V.; Shwartz, B.; Sopov, V.; Stepaniak, J.; Sukhanov, A.; Sukhanov, A.; Tchernychev, V.; Turowiecki, A.; Wagner, G.; Wilhelmi, Z.; Zabierowski, J.; Zernov, A.; Zlomanczuk, J.

1999-01-01

Different π and η meson production channels in proton-proton and proton-deuteron collisions have been studied at the CELSIUS storage ring using an internal cluster-jet target setup [1]. During the last years more emphasis has been put on ππ and all but one of the possible channels in proton-proton collisions have been studied. Recently also the quasi-free p+n→d+η reaction cross section has been measured at threshold using 1295 MeV protons and target deuterium. Excess energies from threshold to 10 MeV in the center of mass of the final dη system were covered. Approaching the threshold the cross section is enhanced compared to phase-space expectations. This behaviour is typical for a strong final-state interaction

Measurement of atomic-hydrogen spin-exchange parameters at 0.5 K using a cryogenic hydrogen maser

International Nuclear Information System (INIS)

Hayden, M.E.; Huerlimann, M.D.; Hardy, W.N.

1996-01-01

Using a cryogenic hydrogen maser, suitably modified to have electronic control of both the resonance frequency and the quality factor of the external cavity, we have measured a number of spin-exchange parameters for an atomic-hydrogen (H) gas at a temperature of 0.5 K. These results are relevant to the ultimate achievable frequency stability for cryogenic H masers and, when coupled with accurate calculations of the spin-exchange parameters, serve as a sensitive test of the H-H interatomic potentials. We find evidence for a frequency shift not predicted by semiclassical theories of spin exchange. In the context of a fully quantum mechanical hydrogen-atom spin-exchange theory [B. J. Verhaar et al., Phys. Rev. A 35, 3825 (1987) and J. M. V. A. Koelman et al., Phys. Rev. A 38, 3535 (1988)], this frequency shift is attributed to the influence of hyperfine interactions during spin-exchange collisions. Our findings are generally in agreement with these predictions; however, the sign of the hyperfine-induced frequency shift appears to differ from theory. copyright 1996 The American Physical Society

Initial state fluctuations and final state correlations in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Luzum, Matthew; Petersen, Hannah

2014-01-01

We review the phenomenology and theory of bulk observables in ultra-relativistic heavy-ion collisions, focusing on recent developments involving event-by-event fluctuations in the initial stages of a heavy-ion collision, and how they manifest in observed correlations. We first define the relevant observables and show how each measurement is related to underlying theoretical quantities. Then we review the prevailing picture of the various stages of a collision, including the state-of-the-art modeling of the initial stages of a collision and subsequent hydrodynamic evolution, as well as hadronic scattering and freeze-out in the later stages. We then discuss the recent results that have shaped our current understanding and identify the challenges that remain. Finally, we point out open issues and the potential for progress in the field. (topical review)

Activities of the JILA Atomic Collisions Cross Sections Data Center

International Nuclear Information System (INIS)

Gallagher, J.W.

1983-01-01

The JILA Atomic Collisions Cross Sections Data Center compiles, critically evaluates, and reviews cross sections and rates for low energy (<100 keV) collisions of electrons, photons, and heavy particles with atoms, ions, and simple molecules. Reports are prepared which provide easily accessible recommended data with error limits, list the fundamental literature related to specific topics, identify regions where data are missing, and point out inconsistencies in existing data. The general methodology used in producing evaluated compilations is described. Recently completed projects and work in progress are reported

Hydrogen, deuterium, and tritium isotope exchange experiments in JET

Energy Technology Data Exchange (ETDEWEB)

Horton, L.D.; Andrew, P.; Bracco, G.; Conroy, S.; Corti, S.; Ehrenberg, J.; Goodall, D.H.J.; Jarvis, O.N.; Lomas, P.; Loughlin, M.; Peacock, A.T.; Saibene, G.; Sadler, G.; Sartori, R.; Stamp, M.F.; Thomas, P.R.; Belle, P. van (JET Joint Untertaking, Abingdon, Oxfordshire (United Kingdom))

1992-12-01

Isotope exchange experiments have been performed in JET using hydrogen, deuterium, and, in the recent preliminary tritium experiment (PTE), tritium. The rate of change-over from one isotope to another involves two quite different time constants. We have modelled this behaviour using a multireservoir model which splits the accessible hydrogenic particles into two groups, each having a different rate of exchange of particles with the plasma. By applying this model to the sequence of discharges during and after the PTE, we can determine the parameters in the model. The resulting fit also gives a good representation of hydrogen/deuterium change-over experiments, indicating that the tritium behaves in the same manner as other hydrogen isotopes, at least as far as recycling is concerned. Discrepancies between the model and the actual measurements of tritium recovery after the PTE lead us to conclude that isotope exchange processes resulting from collisions of molecules with the vessel walls play a significant role in spreading tritrium around the machine. (orig.).

Soil properties and elements other than hydrogen that can affect the ...

African Journals Online (AJOL)

A neutron water meter (NWM) operates on the principle that emitted high-energy neutrons are thermalised by elastic collisions with atomic nuclei present in soil, such as that of the hydrogen atom. Thermalised neutrons, however, are affected by other nuclear-matter interactions such as their capture by soil elements and ...

Hydrogen Infrastructure Market Readiness: Opportunities and Potential for Near-term Cost Reductions; Proceedings of the Hydrogen Infrastructure Market Readiness Workshop and Summary of Feedback Provided through the Hydrogen Station Cost Calculator

Energy Technology Data Exchange (ETDEWEB)

Melaina, M. W.; Steward, D.; Penev, M.; McQueen, S.; Jaffe, S.; Talon, C.

2012-08-01

Recent progress with fuel cell electric vehicles (FCEVs) has focused attention on hydrogen infrastructure as a critical commercialization barrier. With major automakers focused on 2015 as a target timeframe for global FCEV commercialization, the window of opportunity is short for establishing a sufficient network of hydrogen stations to support large-volume vehicle deployments. This report describes expert feedback on the market readiness of hydrogen infrastructure technology from two activities.

b-flavour tagging in pp collisions

CERN Multimedia

Birnkraut, Alex

2015-01-01

An essential ingredient of all time-dependent CP violation studies of B mesons is the ability to tag the initial flavour of the B meson. The harsh environment of 7 and 8 TeV pp collisions makes this a particularly difficult enterprise. We report progresses in the flavour tagging of B0 and Bs mesons, including developments of novel techniques like the use of an opposite side charm tagger.

Transitions between the fine structure components of C+ in collision with atomic hydrogen

International Nuclear Information System (INIS)

Bazet, J.F.; Harel, C.; McCarroll, R.; Riera, A.

1975-01-01

The cross section for excitation of the 2 Psub(1/2)- 2 Psub(3/2) transition in thermal C + ( 2 P)-H( 2 S) collisions is calculated in the framework of the semiclassical approximation using the potential energy curves of the 1 Σ, 1 π, 3 π, 3 Σ states of CH + , determined by an exchange perturbation method. Full account is taken of the exchange interaction and of the trajectory effects induced by the long range polarization potential. For low energies E, such that E/k 350 K, sigma depends on the exchange interaction. The cross section, which presents a maximum of 130a 2 0 for E/k approximately equal to 180 K, is lower by about 50% than that calculated by Weisheit and Lane. The cooling function due to C + -H collisions in the interstellar clouds is computed as a function of the kinetic temperature of the medium. (orig.) [de

Collision processes of hydrocarbon species in hydrogen plasmas. Pt. 3. The Silane-family

CERN Document Server

Janev, R K

2003-01-01

Cross sections are provided for most important collision processes of the Silicon-Hydrides from the ''Silane-family'': SiH sub y (y = 1 - 4) molecules and their ions SiH sub y sup + , with (plasma) electrons and protons. The processes include: electron impact ionization and dissociation of SiH sub y , dissociative excitation, ionization and recombination of SiH sub y sup + ions with electrons, and charge - and atom - exchange in proton collisions with SiH sub y. All important channels of dissociative processes are considered. Information is also provided on the energetics (reactants/products energy loss / gain) of each individual reaction channel. Total and partial cross sections are presented in compact analytic forms. The critical assessment of data, derivation of new data and presentation of results follow closely the concepts of the recently published related databases for Carbon-Hydrides, namely for the Methane family, and for the Ethane- and the Propane families, respectively.

Some results of a numerical calculation of plasma dispersion curves including collisions; Quelques resultats de calcul de courbes de dispersion avec collisions

Energy Technology Data Exchange (ETDEWEB)

Lepechinsky, D; Parlange, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Dispersion curves including the effect of collisions have been calculated with a 7090 IBM computer for several types of laboratory hydrogen plasmas; Te = Ti = 1 eV; Te = 1 eV, Ti = 0,1 eV; Te = 10 eV, Ti = 2 eV; Te = 50 eV, Ti 10 eV, with neutral gas pressures of 10{sup -1}, 10{sup -3} and 10{sup -4} mmHg and electron densities of 10{sup 10}, 10{sup 13} and eventually 10{sup 15} el/cc. The corresponding collision frequencies with neutrals and between electrons and ions have been derived using appropriate relationships The dispersion equations used correspond to the macroscopic treatment. The real and imaginary parts of the wave number K are presented as a function of real values of the frequency {omega}, for electrostatic and electromagnetic waves and for e.m. waves propagating parallel to a permanent magnetic field of 500 gauss and 12.5 Kgauss. (authors) [French] Des courbes de dispersion tenant compte de l'effet des collisions ont ete calculees a l'aide d'un ordinateur IBM 7090 pour differents types de plasmas d'hydrogene se presentant au laboratoire; les temperatures electroniques et ioniques envisagees ont ete les suivantes: Te = Ti = 1 Ev; Te = 1 eV, Ti 0,1 eV; Te = 10 eV, Ti = 2 eV; Te = 50 eV, Ti = 10 eV; les pressions de neutres - de 10{sup -1}, 10{sup -3} et 10{sup -4} mmHg; les densites electroniques - de 10{sup 10}, 10{sup 13} et eventuellement de 10{sup 15} el/cc. Les frequences de collision avec les neutres et entre electrons et ions ont ete evaluees en fonction de ces donnees. Les equations, de dispersion utilisees correspondant au traitement macroscopique. On presente les valeurs des parties reelle et imaginaire du nombre d'ondes K en fonction de valeurs reelles de la frequence {omega} pour les ondes electrostatiques et electromagnetiques et pour les ondes e.m. se propageant parallelement a un champ magnetique permanent de 500 gauss et de 12,5 kgauss. (auteurs)

Protein and Peptide Gas-phase Structure Investigation Using Collision Cross Section Measurements and Hydrogen Deuterium Exchange

Science.gov (United States)

Khakinejad, Mahdiar

Protein and peptide gas-phase structure analysis provides the opportunity to study these species outside of their explicit environment where the interaction network with surrounding molecules makes the analysis difficult [1]. Although gas-phase structure analysis offers a unique opportunity to study the intrinsic behavior of these biomolecules [2-4], proteins and peptides exhibit very low vapor pressures [2]. Peptide and protein ions can be rendered in the gas-phase using electrospray ionization (ESI) [5]. There is a growing body of literature that shows proteins and peptides can maintain solution structures during the process of ESI and these structures can persist for a few hundred milliseconds [6-9]. Techniques for monitoring gas-phase protein and peptide ion structures are categorized as physical probes and chemical probes. Collision cross section (CCS) measurement, being a physical probe, is a powerful method to investigate gas-phase structure size [3, 7, 10-15]; however, CCS values alone do not establish a one to one relation with structure(i.e., the CCS value is an orientationally averaged value [15-18]. Here we propose the utility of gas-phase hydrogen deuterium exchange (HDX) as a second criterion of structure elucidation. The proposed approach incudes extensive MD simulations to sample biomolecular ion conformation space with the production of numerous, random in-silico structures. Subsequently a CCS can be calculated for these structures and theoretical CCS values are compared with experimental values to produce a pool of candidate structures. Utilizing a chemical reaction model based on the gas-phase HDX mechanism, the HDX kinetics behavior of these candidate structures are predicted and compared to experimental results to nominate the best in-silico structures which match (chemically and physically) with experimental observations. For the predictive approach to succeed, an extensive technique and method development is essential. To combine CCS

Photon-photon collisions

Energy Technology Data Exchange (ETDEWEB)

Brodsky, S.J.

1985-01-01

The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

Photon-photon collisions

International Nuclear Information System (INIS)

Brodsky, S.J.

1985-01-01

The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references

Current Development in Treatment and Hydrogen Energy Conversion of Organic Solid Waste

Science.gov (United States)

Shin, Hang-Sik

2008-02-01

This manuscript summarized current developments on continuous hydrogen production technologies researched in Korea advanced institute of science and technology (KAIST). Long-term continuous pilot-scale operation of hydrogen producing processes fed with non-sterile food waste exhibited successful results. Experimental findings obtained by the optimization processes of growth environments for hydrogen producing bacteria, the development of high-rate hydrogen producing strategies, and the feasibility tests for real field application could contribute to the progress of fermentative hydrogen production technologies. Three major technologies such as controlling dilution rate depending on the progress of acidogenesis, maintaining solid retention time independently from hydraulic retention time, and decreasing hydrogen partial pressure by carbon dioxide sparging could enhance hydrogen production using anaerobic leaching beds reactors and anaerobic sequencing batch reactors. These findings could contribute to stable, reliable and effective performances of pilot-scale reactors treating organic wastes.

Antiproton-hydrogen scattering at low-eV energies

International Nuclear Information System (INIS)

Morgan Jr., D.L.

1993-01-01

In the scattering of negative particles other than the electron by atoms at lab-frame energies around 10 eV, an elastic process termed 'brickwall scattering' might lead to a high probability for scattering angles around 180deg. For an antiproton slowing in hydrogen, this backward scattering would result in the loss of nearly all of its energy in a single collision, since it and a hydrogen atom have nearly the same mass. Such energy loss would have a significant effect on the energy distribution of antiprotons at energies where capture by the protons of hydrogen is possible and might, thereby, affect the capture rate and the distribution of capture states. In the semiclassical treatment of the problem with an adiabatic potential energy, brickwall scattering is indeed present, and with a substantial cross section. However, this model appears to underestimate inelastic processes. Based on calculations for negative muons on hydrogen atoms, these processes appear to occur for about the same impact parameters as brickwall scattering and thus substantially reduce its effect. (orig.)

Advances in ultracold collisions: Experimentation and theory

International Nuclear Information System (INIS)

Weiner, J.

1995-01-01

Collisions between optically cooled and trapped atoms have been the subject of intensive investigation since early proposals discussed their novel features and key importance to the achievement of a gaseous ensemble in a single quantum state. Progress in both experimentation and theory has accelerated rapidly over the last three years, and two reviews, one emphasizing theory and the other, experiments, recount the state of the art published up to about the midpoint of 1993. The purpose of this chapter is to update continuing lines of research set forth in these and earlier works and to relate new results, establishing novel directions for investigation that have appeared in the literature. Two principal questions motivate research into the nature of ultracold collisions: (1) what new phenomena arise when collisionally interacting particles also exchange photons with modes of the radiation field and (2) what are the important two-body collisional heating mechanisms and how can they be overcome in order to achieve the temperature and density conditions appropriate for Bose-Einstein condensation (BEC)? In fact these two questions are not mutually exclusive, and one of the most notable developments in the past year, relevant to both, has been the demonstration of optical control of two-body ultracold collisional processes. Other important issues touching, on one or both of these questions are the magnitude and sign of the scattering length in s-wave collisions between species in various well-defined quantum states, progress in high-resolution trap loss and photoassociation spectroscopy, and application of optical cooling and compression to atomic beams. 58 refs., 21 figs

Electron transfer processes in ion collisions with atomic hydrogen. Final report for period February 1, 1975--June 30, 1976

International Nuclear Information System (INIS)

Bayfield, J.E.

1976-07-01

Results of experiments completed with Yale equipment coupled to the Oak Ridge Test Bench and Tandem Accelerator facilities are presented. Electron transfer cross sections have been measured at keV collision energies for B, C, N and O ions colliding with H, H 2 , Ar and He gas targets. The ion charge states studied range from +2 through +5. Also reported are cross sections for Si and Fe ions on H, H 2 and Ar at energies between 1.5 and 14 MeV, with charge states varying between +5 and +13. Also measured were the cross sections for H + collisions with H, H 2 and Ar for energies between 0.8 and 2.5 MeV. At keV energies the cross sections for highly charged B, C, N and O ions are found to be 1 x 10 -14 cm 2 . The cross sections for 4 MeV Fe ions scale roughly with the square of the ion charge, and have values as high as 0.5 x 10 -14 cm 2 for Fe 10+ + H collisions. A strong energy dependence is found for Fe ion collisions between 4 and 14 MeV. Previous results for MeV H + + Ar collisions are nicely reproduced, while our first results for the fundamental MeV H + - H collision problem are cross sections higher than many theoretical predictions

Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project

Energy Technology Data Exchange (ETDEWEB)

Stottler, Gary

2012-02-08

General Motors, LLC and energy partner Shell Hydrogen, LLC, deployed a system of hydrogen fuel cell electric vehicles integrated with a hydrogen fueling station infrastructure to operate under real world conditions as part of the U.S. Department of Energy's Controlled Hydrogen Fleet and Infrastructure Validation and Demonstration Project. This technical report documents the performance and describes the learnings from progressive generations of vehicle fuel cell system technology and multiple approaches to hydrogen generation and delivery for vehicle fueling.

Kinematics of 3-body in Ionization Collision

International Nuclear Information System (INIS)

Della Picca, Renata

2003-01-01

In this thesis we study three body problems in the frame of the collision theory. First, we deal with the process of autoionization by ion impact where the line profile of the electron emitted is strongly affected by the post-collision interaction with the Coulomb field of the outgoing projectile.Here we analyze how these effects are modified when the projectile velocity is in the close vicinity of the resonant electron velocity.In this energy range, the analysis of the resonance contribution is hindered by the characteristic 'electron capture to the continuum' divergence in the direct term.Here we present a detailed theoretical study of the interplay between both contributions, based on a generalization of the Final-State Interaction model.Finally we propose a modified parameterization of the autoionization line shape in the vicinity of the ECC cusp.Secondly, we study the direct ionization of an atomic target by the impact of a charge projectile, through analysis of the quintuple differential cross section (QDCS) which gives the most complete information about a ionization collision.Its study, without any approximation on the mass ratios can unveil new, not previously observed, structures.In particular, in this work the ionization of Hydrogen molecules by the impact of positrons and muons was studied and a new structure that has not been identified until now was found. Its main characteristics and a possible explanation are presented

Observation of luminescent spectra in low energy ion-neutral collisions. Progress report, June 1, 1976--May 31, 1978

International Nuclear Information System (INIS)

Leventhal, J.J.

1978-01-01

The experiments reported provide detailed information on the fundamental nature of energy transfer processes in ion-molecule or atom-molecule collisions. By combining ion beam techniques with emission spectroscopy, data are obtained which directly lead to internal energy state distributions of atomic and molecular products of these collisions. Data are in the form of emission spectra from nascent energetically excited species formed in the energy transfer process. Changes in the collision-produced spectra as a function of beam kinetic energy yield information on the extent of energy conversion (kinetic → internal) in the collision process. Some of the specific energy transfer processes studied are applicable to the problem of achieving inverted energy level populations in high pressure gas lasers. Also discussed are experiments designed to test theoretical models which predict product energy partitioning in molecular collisions. Because experimentally determined energy state distributions deviate substantially from the predicted distributions it is concluded that additional theoretical work is needed. A simple model was developed which qualitatively reproduces the important features of the data. This model, which is considerably more general than those previously available is outlined and briefly discussed

Progress in materials-based hydrogen storage at Hysa infrastructure in South Africa

CSIR Research Space (South Africa)

Langmi, Henrietta W

2015-10-01

Full Text Available The South African Department of Science and Technology (DST) developed the National Hydrogen and Fuel Cells Technologies (HFCT) Research, Development and Innovation (RDI) Strategy, which was branded Hydrogen South Africa (HySA). HySA was established...

Collision dynamics probed by convoy electron emission

International Nuclear Information System (INIS)

Seliger, M.; Burgdoerfer, J.; Toekesi, K.; Reinhold, C.O.; Takabayashi, Y.; Ito, T.; Komaki, K.; Azuma, T.; Yamazaki, Y.; RIKEN, Saitama

2002-01-01

The description of the collision mechanisms was examined by the emission of convoy electrons as a result of the transport of an Ar 17+ ion with an energy of 390 MeV/amu through self-supporting amorphous carbon foils of thickness varying from 25 to 9190 μg/cm 2 . A classical trajectory Monte Carlo (CTMC) simulation of the random walk of the electron initially attached to the relativistic hydrogenic Argon ion was performed. Measurements were made of the final kinetic energy of the emitted convoy electrons at the Heavy Ion Medical Accelerator in Chiba (HIMAC). (R.P.)

Muon transfer from muonic hydrogen to heavier atoms; Transfert de charge muonique

Energy Technology Data Exchange (ETDEWEB)

Dupays, A

2004-06-01

This work concerns muon transfer from muonic hydrogen to heavier atoms. Recently, a method of measurement of the hyperfine structure of ground-state muonic hydrogen based on the collision energy dependence of the muon transfer rate to oxygen has been proposed. This proposal is based on measurements which where performed at the Paul Scherrer Institute in the early nineties which indicate that the muon transfer from muonic hydrogen to oxygen increases by a factor of 4 going from thermal to 0.12 eV energies. The motivation of our calculations was to confirm this behaviour. To study the collision energy dependence of the muon transfer rate, we have used a time-independent close-coupling method. We have set up an hyperspherical elliptic formalism valid for nonzero total angular momentum which allows accurate computations of state-to-state reactive and charge exchange processes. We have applied this formalism to muon-transfer process to oxygen and neon. The comparison with experimental results is in both cases excellent. Finally, the neon transfer rate dependence with energy suggests to use neon instead of oxygen to perform a measurement of the hyperfine structure of muonic hydrogen. The results of accurate calculations of the muon transfer rates from muonic protium and deuterium atoms to nitrogen, oxygen and neon are also reported. Very good agreement with measured rates is obtained and for the three systems, the isotopic effect is perfectly reproduced. (author)

Progress in the application of classical S-matrix theory to inelastic collision processes

International Nuclear Information System (INIS)

McCurdy, C.W.; Miller, W.H.

1980-01-01

Methods are described which effectively solve two of the technical difficulties associated with applying classical S-matrix theory to inelastic/reactive scattering. Specifically, it is shown that rather standard numerical methods can be used to solve the ''root search'' problem (i.e., the nonlinear boundary value problem necessary to impose semiclassical quantum conditions at the beginning and the end of the classical trajectories) and also how complex classical trajectories, which are necessary to describe classically forbidden (i.e., tunneling) processes, can be computed in a numerically stable way. Application is made to vibrational relaxation of H 2 by collision with He (within the helicity conserving approximation). The only remaining problem with regard to applying classical S-matrix theory to complex collision processes has to do with the availability of multidimensional uniform asymptotic formulas for interpolating the ''primitive'' semiclassical expressions between their various regions of validity

1984-85 ISN progress report

International Nuclear Information System (INIS)

1985-01-01

This progress report ISN 1984-1985 deals with the following subjects: nuclear physics theory, peripheral and intermediate energy physics, characteristics of reaction mechanisms in heavy ion collisions, nuclear structure, fundamental interactions, experimental methods and new instrumentation, some interdisciplinary research activities and technical activities, the SARA cyclotron and finally, technology transfer and valorisation [fr

Hydrodynamic modelling for relativistic heavy-ion collisions at RHIC ...

Indian Academy of Sciences (India)

model, to describe the microscopic evolution and decoupling of the hadronic ... progress on hydrodynamic modelling, investigation on the flow data and the ... and to describe and predict the soft particle physics in relativistic heavy-ion collisions [4]. It is based on the conservation laws of energy, momentum and net charge ...

US-Japan Workshop on atomic-collision data for fusion

International Nuclear Information System (INIS)

Crandall, D.H.; Hafford, P.M.; Itikawa, Y.

1981-04-01

This report, containing abstracts of each of the presentations and discussions, includes: brief talks on the applications of atomic data in tokamaks and in inertial confinement; reviews of the specific atomic collisions projects for fusion in Japan and the United States; discussions of how the data centers operate and manner of exchanging data; brief reviews of the status of electron-ion scattering and ion-atom scattering; discussions of criteria to be used in evaluating and selecting both experimental and theoretical data in these two areas; comparisons of data selected for each of six specific collision reactions which were evaluated by both groups prior to the workshop; brief reviews of activities in the related areas of atomic structure and plasma wall interactions; and a decision to pursue a joint or collaborative compilation of recommended cross sections for oxygen ions for electron impact excitation and electron capture from atomic hydrogen

Technical Integration of Nuclear Hydrogen Production Technology

International Nuclear Information System (INIS)

Lee, Ki Young; Chang, J. H.; Park, J. K.

2007-06-01

These works focus on the development of attainment indices for nuclear hydrogen key technologies, the analysis of the hydrogen production process and the performance estimation for hydrogen production system, and the assessment of the nuclear hydrogen production economy. To estimate the attainments of the key technologies in progress with the performance goals of GIF, itemized are the attainment indices based on SRP published in VHTR R and D steering committee of Gen-IV. For assessing the degree of attainments in comparison with the final goals of VHTR technologies in progress of researches, subdivided are the prerequisite items conformed to the NHDD concepts established in a preconceptual design in 2005. The codes for analyzing the hydrogen production economy are developed for calculating the unit production cost of nuclear hydrogen. We developed basic R and D quality management methodology to meet design technology of VHTR's needs. By putting it in practice, we derived some problems and solutions. We distributed R and D QAP and Q and D QAM to each teams and these are in operation. Computer simulations are performed for estimating the thermal efficiency for the electrodialysis component likely to adapting as one of the hydrogen production system in Korea and EED-SI process known as the key components of the hydrogen production systems. Using the commercial codes, the process diagrams and the spread-sheets were produced for the Bunsen reaction process, Sulphuric Acid dissolution process and HI dissolution process, respectively, which are the key components composing of the SI process

Ultrahigh-pressure transitions in solid hydrogen

International Nuclear Information System (INIS)

Mao, H.; Hemley, R.J.

1994-01-01

During the past five years, major progress has been made in the experimental study of solid hydrogen at ultrahigh pressures as a result of developments in diamond-cell technology. Pressures at which metallization has been predicted to occur have been reached (250--300 Gigapascals). Detailed studies of the dynamic, structural, and electronic properties of dense hydrogen reveal a system unexpectedly rich in physical phenomena, exhibiting a variety of transitions at ultrahigh pressures. This colloquium explores the study of dense hydrogen as an archetypal problem in condensed-matter physics

Correlation effects in electron-atom collisions

International Nuclear Information System (INIS)

Water, W. van de.

1981-01-01

This thesis deals with correlation effects occurring in the outer region of configuration space after an ionising collision. The motion of both escaping electrons in the external region is then fully determined by the long-range Coulomb forces. Firstly the threshold ionisation of hydrogen-like targets is studied. In that case two slow electrons attempt to escape from the Coulomb attraction of the residual ion. Secondly ionising collisions, with the formation of an autoionising state as an intermediate step, are considered. Such an autoionising state is in fact a quasi bound state of the neutral atom which lies imbedded in the ionisation continuum. The state decays after a certain lifetime by emission of an electron. Of all states to be formed in the reaction region only the autoionising state(s) under consideration is then relevant for this type of ionisation process. The energy positions of autoionising states usually are such that the electron to be ionised is ejected with a rather large velocity. The correlation in the outer region of configuration space then consists of the interaction of a fast ejected electron and, in case of threshold excitation of the autoionising state, a slow scattered electron. (Auth.)

Charge Transfer in Collisions of S^4+ with H.

Science.gov (United States)

Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

2001-05-01

Charge transfer processes due to collisions of ground state S^4+ ions with atomic hydrogen were investigated for energies between 1 meV/u and 10 MeV/u using the quantum-mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC), and continuum distorted wave methods. The MOCC calculations utilized ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially-stripped S^3+ excited classical states. Hydrogen target isotope effects were explored and rate coefficients for temperatures between 100 and 10^6 K will be presented

Interaction of atomic hydrogen with ethylene adsorbed on nickel films

International Nuclear Information System (INIS)

Korchak, V.N.; Tret'yakov, I.I.; Kislyuk, M.U.

1976-01-01

The reactivity of ethylene adsorbed on the pure films of nickel at various temperatures was studied with respect to hydrogen atoms generated in the gaseous phase. The experiments were conducted in a glass vacuum apparatus enabling one to obtain the highest vacuum up to 2x20 -10 torr. The catalyst, nickel films, was produced by their deposition onto the walls of the glass reactor at a pressure of the residual gas of 10 -9 torr and a temperature of the walls of 25 deg C. Gas purity was analyzed by the mass spectrometric method. The ethylene adsorbed at the temperatures below 173 deg K reacted readily with the hydrogen atoms to yield ethane. The process ran without practically any activation energy involved and was limited by the attachment of the first hydrogen atom to the ethylene molecule. The efficiency of this interaction was 0.02 of the number of the hydrogen atoms collisions against the surface occupied by the ethylene. The adsorption of the ethylene at room and higher temperatures was accompanied by its disproportioning with the release of the hydrogen into the gaseous phase and a serious destruction of the ethylene molecules adsorbed to produce hydrogen residues interacting with neither molecular nor atomic hydrogen [ru

The hydrogen village: building hydrogen and fuel cell opportunities

International Nuclear Information System (INIS)

Smith, R.

2006-01-01

The presentation addressed the progress the Hydrogen Village Program has made in its first 24 months of existence and will provide an understanding of the development of new markets for emerging Hydrogen and Fuel Cell technologies based on first hand, real world experience. The Hydrogen Village (H2V) is an End User driven, Market Development Program designed to accelerate the sustainable commercialization of hydrogen and fuel cell technologies through awareness, education and early deployments throughout the greater Toronto area (GTA). The program is a collaborative public-private partnership of some 35 companies from a broad cross section of industry administered through Hydrogen and Fuel Cells Canada and funded by the Governments of Canada and Ontario. The intent of the H2V is to develop markets for Hydrogen and Fuel Cell technologies that benefit the local and global community. The following aspects of market development are specifically targeted: 1) Deployments: of near market technologies in all aspects of community life (stationary and mobile). All applications must be placed within the community and contact peoples in their day-to-day activity. End user involvement is critical to ensure that the applications chosen have a commercial justification and contribute to the complementary growth of the market. 2) Development: of a coordinated hydrogen delivery and equipment service infrastructure. The infrastructure will develop following the principles of conservation and sustainability. 3) Human and societal factors: - Public and Corporate policy, public education, Codes/ Standards/ Regulations - Opportunity for real world implementation and feedback on developing codes and standards - Build awareness among regulatory groups, public, and the media. The GTA Hydrogen Village is already well under way with strategically located projects covering a wide range of hydrogen and fuel cell applications including: Residential heat and power generation using solid oxide

Hydrogen behavior in light-water reactors

International Nuclear Information System (INIS)

Berman, M.; Cummings, J.C.

1984-01-01

The Three Mile Island accident resulted in the generation of an estimated 150 to 600 kg of hydrogen, some of which burned inside the containment building, causing a transient pressure rise of roughly 200 kPa (2 atm). With this accident as the immediate impetus and the improved safety of reactors as the long-term goal, the nuclear industry and the Nuclear Regulatory Commission initiated research programs to study hydrogen behavior and control during accidents at nuclear plants. Several fundamental questions and issues arise when the hydrogen problem for light-water-reactor plants is examined. These relate to four aspects of the problem: hydrogen production; hydrogen transport, release, and mixing; hydrogen combustion; and prevention or mitigation of hydrogen combustion. Although much has been accomplished, some unknowns and uncertainties still remain, for example, the rate of hydrogen production during a degraded-core or molten-core accident, the rate of hydrogen mixing, the effect of geometrical structures and scale on combustion, flame speeds, combustion completeness, and mitigation-scheme effectiveness. This article discusses the nature and extent of the hydrogen problem, the progress that has been made, and the important unresolved questions

Quantum-mechanical calculation of three-dimensional atom-diatom collisions in the presence of intense laser radiation

Science.gov (United States)

Devries, P. L.; George, T. F.

1979-01-01

A formalism is presented for describing the collision of fluorine with the hydrogen molecule in the presence of intense radiation. For a laser frequency on the order of the spin-orbit splitting of fluorine, the interaction of the molecular system with the radiation occurs at relatively long range where, for this system, the electric dipole is vanishingly small. Hence the interaction occurs due to the magnetic dipole coupling. Even so, at low collision energies a substantial enhancement of the quenching cross section is found for a radiation intensity of 10 to the 11th W/sq cm.

Spin alignment and violation of the OZI rule in exclusive omega and phi production in pp collisions

Czech Academy of Sciences Publication Activity Database

Adolph, C.; Akhunzyanov, R.; Alekseev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V. A.; Austregisilio, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Donskov, S.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.V.; Elia, C.; Eversheim, P.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grube, B.; Grussemmeyer, T.; Guskov, A.; Guthörl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.; Herrmann, F.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joerg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.; Kolosov, V.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.; Kotzinian, A.; Kouznetsov, O.; Král, Z.; Krämer, M.; Kroumchtein, Z.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Y.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nový, J.; Nikolaenko, V.; Nowak, W. D.; Nunes, A.S.; Orlov, I.; Olshevsky, A.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pešek, M.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V.; Sandacz, A.; Sapozhnikov, M.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlütter, T.; Schmidt, A.; Schmidt, K.; Schmiden, H.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Steiger, L.; Srnka, Aleš; Stolarski, M.; Sulc, M.; Suzuki, H.; Sulej, R.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

2014-01-01

Roč. 886, SEP 2014 (2014), s. 1078-1101 ISSN 0550-3213 R&D Projects: GA MŠk(CZ) LO1212 Keywords : OZI rule * vector meson * pp collision * liquid hydrogen target Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.929, year: 2014

Progress of research on the mechanism of microstructure evolution during irradiation with collision cascades

International Nuclear Information System (INIS)

Kiritani, Michio

1997-01-01

Progress of the research on microstructural evolution during radiation damage accompanied with collision cascades, particularly by neutrons, is summarized from the researches reported in 1995 and 1996. The major part of irradiation was performed with JMTR (Japan Material Testing Reactor), and comparisons were made with the result of D-T fusion neutron irradiation with RTNS-II (Rotating Target Neutron Source, LLNL). The subjects concerned are: (1) Microstructure evolution during irradiation, (2) Processes controlling the accumulation of defects during cascade damage, (3) Subcascades from the viewpoint of point defect cluster formation, (4) Mechanism of suppression of microstructure evolution during temperature cycle neutron irradiation of nickel, (5) Identification of the nature of neutron-irradiation-induced point defect clusters in copper by means of electron irradiation, (6) Easy one-dimensional motion of small interstitial clusters, (7) Identification of the nature of small point defect clusters in neutron irradiated Fe-16Ni-15Cr, (8) Spatial distribution of nucleation of point defect clusters by high energy particle irradiation, (9) Crystallographic orientation dependence of dislocation structures in neutron irradiated metals, (10) Examination of defect accumulation mode with multi-section-removable-irradiation-rig in Japan Material Testing Reactor, (11) Estimation of freely migrating point defects during cascade damage by the growth of helical dislocations, (12) Identification of the nature of neutron-irradiation-induced small point defect clusters in Nickel by means of electron irradiation, (13) Thermal stability of point defect clusters in neutron irradiated Fe-16Ni-15Cr. (author)

Research Progress on the Indirect Hydrogenation of Carbon Dioxide to Methanol.

Science.gov (United States)

Du, Xian-Long; Jiang, Zheng; Su, Dang Sheng; Wang, Jian-Qiang

2016-02-19

Methanol is a sustainable source of liquid fuels and one of the most useful organic chemicals. To date, most of the work in this area has focused on the direct hydrogenation of CO2 to methanol. However, this process requires high operating temperatures (200-250 °C), which limits the theoretical yield of methanol. Thus, it is desirable to find a new strategy for the efficient conversion of CO2 to methanol at relatively low reaction temperatures. This Minireview seeks to outline the recent advances on the indirect hydrogenation of CO2 to methanol. Much emphasis is placed on discussing specific systems, including hydrogenation of CO2 derivatives (organic carbonates, carbamates, formates, cyclic carbonates, etc.) and cascade reactions, with the aim of critically highlighting both the achievements and remaining challenges associated with this field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scientific progress report 1/1975

International Nuclear Information System (INIS)

1975-01-01

Review articles report on the progress in research and development in the fields theoretical physics, nuclear reactions, nuclear moments and internal fields, nuclear collision processes, VICKSI. The publications of the HMI department nuclear and radiation physics in the form of scientific publications, theses, conference papers, colloquium papers, as well as the members are listed. (HK) [de

Collisions of Beq+ and Bq+ ions with H, H2 and He

International Nuclear Information System (INIS)

Phaneuf, R.A.; Janev, R.K.; Tawara, H.; Kimura, M.; Krstic, P.S.; Peach, G.; Mazing, M.A.

1991-01-01

This Working Group Report discusses the available data on cross sections for collisions of beryllium ions and boron ions with atomic and molecular hydrogen and helium for the purpose of applications for plasma diagnostics and modelling of the plasma edge for low energies, and for plasma diagnostics and energy deposition for high energies. In particular, charge exchange, excitation, ionization and two-electron processes are discussed. 43 refs, 1 tab

Jagiellonian University Study of Hadronic Hydrogen-like Atoms in the DIRAC Experiment at PS CERN

CERN Document Server

Afanasyev, L

2017-01-01

Production of hadronic hydrogen-like atoms at high-energy collisions and method of their observation are considered. Main results of the DIRAC experiment on observation and lifetime measurement of atoms formed by pairs of charged pion–pion and pion–kaon are presented.

Intramolecular migration of amide hydrogens in protonated peptides upon collisional activation

DEFF Research Database (Denmark)

Jørgensen, Thomas J. D.; Gårdsvoll, H.; Ploug, M.

2005-01-01

Presently different opinions exist as to the degree of scrambling of amide hydrogens in gaseous protonated peptides and proteins upon collisional activation in tandem mass spectrometry experiments. This unsettled controversy is not trivial, since only a very low degree of scrambling is tolerable...... if collision-induced dissociation (CID) should provide reliable site-specific information from (1)H/(2)H exchange experiments. We have explored a series of unique, regioselectively deuterium-labeled peptides as model systems to probe for intramolecular amide hydrogen migration under low-energy collisional...... are protected against exchange with the solvent, while the amide hydrogens of the nonbinding sequences exchange rapidly with the solvent. We have utilized such long-lived complexes to generate peptides labeled with deuterium in either the binding or nonbinding region, and the expected regioselectivity...

Vibrational excitation in a hydrogen volume source

International Nuclear Information System (INIS)

Eenshuistra, P.J.

1989-01-01

In this thesis the complex of processes which determines the D - or H - density in a volume source, a hydrogen discharge, is studied. D - beams are of interest for driving the current of a fusion plasma in a TOKAMAK. Densities of vibrationally excited molecules, of H atoms, and of metastable hydrogen molecules were determined using Resonance-Enhanced MultiPhoton Ionization (REMPI). An experiment in which vibrationally highly excited molecules are formed by recombination of atoms in a cold metal surface, is described. The production and destruction of vibrationally excited molecules and atoms in the discharge is discussed. The vibrational distribution for 3≤ν≤5 (ν = vibrational quantumnumber) is strongly super-thermal. This effect is more apparent at higher discharge current and lower gas pressure. The analysis with a model based on rate equations, which molecules are predominantly produced by primary electron excitation of hydrogen molecules and deexcited upon one wall collision. The atom production is compatible with dissociation of molecules by primary electrons, dissociation of molecules on the filaments, and collisions between positive ions and electrons. The electrons are predominantly destroyed by recombination on the walls. Finally the production and destruction of H - in the discharge are discussed. The density of H - in the plasma, the electron density and temperature were determined. H - extraction was measured. The ratio of the extracted H - current and the H - density in the plasma gives an indication of the drift velocity of H - in the plasma. This velocity determines the emittance of the extracted beam. It was found that the H - velocity scales with the square root of the electron temperature. The measured H - densities are compatible with a qualitative model in which dissociative attachment of plasma electrons to vibrationally excited molecules is the most important process. (author). 136 refs.; 39 figs.; 10 tabs

Elastic collisions of classical point particles on a finite frictionless linear track with perfectly reflecting endpoints

Science.gov (United States)

DeLuca, R.

2006-03-01

Repeated elastic collisions of point particles on a finite frictionless linear track with perfectly reflecting endpoints are considered. The problem is analysed by means of an elementary linear algebra approach. It is found that, starting with a state consisting of a projectile particle in motion at constant velocity and a target particle at rest in a fixed known position, the points at which collisions occur on track, when plotted versus progressive numerals, corresponding to the collisions themselves, show periodic patterns for a rather large choice of values of the initial position x(0) and on the mass ratio r. For certain values of these parameters, however, only regular behaviour over a large number of collisions is detected.

Dynamics in ion-molecule collisions at high velocities: One- and two-electron processes

International Nuclear Information System (INIS)

Wang, Yudong.

1992-01-01

This dissertation addresses the dynamic interactions in ion-molecule collisions. Theoretical methods are developed for single and multiple electron transitions in fast collisions with diatomic molecules by heavy-ion projectiles. Various theories and models are developed to treat the three basic inelastic processes (excitation, ionization and charge transfer) involving one and more electrons. The development, incorporating the understanding of ion-atom collision theories with some unique characteristics for molecular targets, provides new insights into phenomena that are absent from collisions with atomic targets. The influence from the multiple scattering centers on collision dynamics is assessed. For diatomic molecules, effects due to a fixed molecular orientation or alignment are calculated and compared with available experimental observations. Compared with excitation and ionization, electron capture, which probes deeper into the target, presents significant two-center interference and strong orientation dependence. Attention has been given in this dissertation to exploring mechanisms for two-and multiple electron transitions. Application of independent electron approximation to transfer excitation from molecular hydrogen is studied. Electron-electron interaction originated from projectile and target nuclear centers is studied in conjunction with the molecular nature of target. Limitations of the present theories and models as well as possible new areas for future theoretical and experimental applications are also discussed. This is the first attempt to describe multi-electron processes in molecular dynamics involving fast highly charged ions

Electron Capture in Slow Collisions of Si4+ With Atomic Hydrogen

Science.gov (United States)

Joseph, D. C.; Gu, J. P.; Saha, B. C.

2009-10-01

In recent years the charge transfer involving Si4+ and H at low energies has drawn considerable attention both theoretically and experimentally due to its importance not only in astronomical environments but also in modern semiconductor industries. Accurate information regarding its molecular structures and interactions are essential to understand the low energy collision dynamics. Ab initio calculations are performed using the multireference single- and double-excitation configuration-interaction (MRD-CI) method to evaluate potential energies. State selective cross sections are calculate using fully quantum and semi-classical molecular-orbital close coupling (MOCC) methods in the adiabatic representation. Detail results will be presented in the conference.

Quantum screening effects on the ion-ion collisions in strongly coupled semiclassical plasmas

International Nuclear Information System (INIS)

Ki, Dae-Han; Jung, Young-Dae

2010-01-01

The quantum screening effects on the ion-ion collisions are investigated in strongly coupled semiclassical hydrogen plasmas. The method of stationary phase and effective interaction potential containing the quantum mechanical effect are employed to obtain the scattering phase shift and scattering cross section as functions of the impact parameter, collision energy, de Broglie wavelength, and Debye length. The result shows that the scattering phase and cross section decrease with increasing de Broglie wavelength. It is also shown that the scattering cross section increases with an increase of the Debye length. Hence, it is found that the quantum effect suppresses the scattering cross section. In addition, the quantum effect on the scattering cross section is found to be more important in small Debye length domains.

Experiments on continuum electron capture in atomic hydrogen and collisional interaction of trapped ions. Progress report

International Nuclear Information System (INIS)

Sellin, I.A.; Elston, S.B.

1981-01-01

This section describes the background and scope of as well as progress made on experiments designed to test the present theory of charge exchange to continuum for the case of bare nuclei on atomic hydrogen. The charge transfer process is well known to be an essential ingredient of any attempt to understand the ionization of gaseous media traversed by highly-charged energetic ions. Surprisingly, a sometimes dominant contribution to such ionization remained undiscovered until the past decade. This process, known as charge transfer to the continuum, involves the ionization of electrons from the target species into unbound states closely matched in exit direction and speed to the charged particles which generate them. Subsequent measurements of the resultant forward electron production, performed by University of Tennessee searchers at Oak Ridge and Brookhaven National Laboratories, were unique in employing more highly charged projectiles than previously

Reflection properties of hydrogen ions at helium irradiated tungsten surfaces

International Nuclear Information System (INIS)

Doi, K; Tawada, Y; Kato, S; Sasao, M; Kenmotsu, T; Wada, M; Lee, H T; Ueda, Y; Tanaka, N; Kisaki, M; Nishiura, M; Matsumoto, Y; Yamaoka, H

2016-01-01

Nanostructured W surfaces prepared by He bombardment exhibit characteristic angular distributions of hydrogen ion reflection upon injection of 1 keV H + beam. A magnetic momentum analyzer that can move in the vacuum chamber has measured the angular dependence of the intensity and the energy of reflected ions. Broader angular distributions were observed for He-irradiated tungsten samples compared with that of the intrinsic polycrystalline W. Both intensity and energy of reflected ions decreased in the following order: the polycrystalline W, the He-bubble containing W, and the fuzz W. Classical trajectory Monte Carlo simulations based on Atomic Collision in Amorphous Target code suggests that lower atom density near the surface can make the reflection coefficients lower due to increasing number of collisions. (paper)

HYDROGEN CONCENTRATIONS IN SULFATE-REDUCING ESTUARINE SEDIMENTS DURING PCE DEHALOGENATION

Science.gov (United States)

Despite recent progress made evaluating the role of hydrogen (H2) as a key electron donor in the anaerobic remediation of chloroethenes, few studies have focused on the evaluation of hydrogen thresholds relative to reductive dehalogenation in sulfidogenic environments. Competitio...

Precursors-Derived Ceramic Membranes for High-Temperature Separation of Hydrogen

OpenAIRE

Yuji, Iwamoto

2007-01-01

This review describes recent progress in the development of hydrogen-permselective ceramic membranes derived from organometallic precursors. Microstructure and gas transport property of microporous amorphous silica-based membranes are briefly described. Then, high-temperature hydrogen permselectivity, hydrothermal stability as well as hydrogen/steam selectivity of the amorphous silica-based membranes are discussed from a viewpoint of application to membrane reactors for conversion enhancement...

Absolute fragmentation cross sections in atom-molecule collisions : Scaling laws for non-statistical fragmentation of polycyclic aromatic hydrocarbon molecules

NARCIS (Netherlands)

Chen, T.; Gatchell, M.; Stockett, M. H.; Alexander, J. D.; Zhang, Y.; Rousseau, P.; Domaracka, A.; Maclot, S.; Delaunay, R.; Adoui, L.; Huber, B. A.; Schlathölter, T.; Schmidt, H. T.; Cederquist, H.; Zettergren, H.

2014-01-01

We present scaling laws for absolute cross sections for non-statistical fragmentation in collisions between Polycyclic Aromatic Hydrocarbons (PAH/PAH+) and hydrogen or helium atoms with kinetic energies ranging from 50 eV to 10 keV. Further, we calculate the total fragmentation cross sections

The hydrogen village in the Greater Toronto Area (GTA)

International Nuclear Information System (INIS)

Kimmel, T.B.; Smith, R.

2004-01-01

'Full text:' A Hydrogen Village (H2V) is a public/private partnership with an objective to accelerate the commercialization of hydrogen and fuel cell technology in Canada and firmly position Canada as the international leader in this sector. The first Hydrogen Village is planned for the Greater Toronto Area (GTA) and will make use of existing hydrogen and fuel cell deployments to assist in its creation. This five year GTA Hydrogen Village program is planned to begin operations in 2004. The Hydrogen Village will demonstrate and deploy various hydrogen production and delivery techniques as well as fuel cells for stationary, transportation (mobile) and portable applications. This paper will provide an overview of the Hydrogen Village and identify the missions, objectives, members and progress within the H2V. (author)

Classical/quantum correspondence in state selective charge transfer and excitation reactions involving highly charged ions and hydrogen

International Nuclear Information System (INIS)

Purkait, M

2009-01-01

State selective charge transfer and excitation cross sections for collisions of Ne q+ (q = 1-10) with atomic hydrogen are calculated within the framework of Classical Trajectory Monte Carlo (CTMC) method and Boundary Corrected Continuum Intermediate State (BCCIS) approximation.

Development of a Laser-based Emittance Monitor for Negative Hydrogen Beams

CERN Document Server

AUTHOR|(CDS)2078368; Schmauss, Bernhard; Gibson, Stephen; Boorman, Gary; Bosco, Alessio

High energy particle accelerators are designed to collide charged particle beams and thus study the collision products. Maximising the collision rate, to generate sufficient statistics for precise measurements of rare processes, is one of the key parameters for optimising the overall collider performance. The CERN Large Hadron Collider (LHC) Injectors Upgrade (LIU) includes the construction of LINAC4, a completely new machine working as a first linear acceleration stage for the LHC beam. By accelerating a negative hydrogen beam (H-) instead of protons, it aims to double the beam brightness via a more efficient transfer to the first circular accelerator and subsequently boost the LHC collision rate. To achieve this, a precise knowledge of the transverse beam characteristics in terms of beam emittance is essential. This thesis work covers the development of a laser-based monitor meant to measure non-destructively the LINAC4 beam transverse profile and emittance. This included the implementation of dif...

Antiprotonic-hydrogen atoms

International Nuclear Information System (INIS)

Batty, C.J.

1989-07-01

Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

Thermodynamic Tuning of Mg-Based Hydrogen Storage Alloys: A Review

Science.gov (United States)

Zhu, Min; Lu, Yanshan; Ouyang, Liuzhang; Wang, Hui

2013-01-01

Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH2 are alloying, nanostructuring, and changing the reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored reaction enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys. PMID:28788353

Collision group and renormalization of the Boltzmann collision integral

Science.gov (United States)

Saveliev, V. L.; Nanbu, K.

2002-05-01

On the basis of a recently discovered collision group [V. L. Saveliev, in Rarefied Gas Dynamics: 22nd International Symposium, edited by T. J. Bartel and M. Gallis, AIP Conf. Proc. No. 585 (AIP, Melville, NY, 2001), p. 101], the Boltzmann collision integral is exactly rewritten in two parts. The first part describes the scattering of particles with small angles. In this part the infinity due to the infinite cross sections is extracted from the Boltzmann collision integral. Moreover, the Boltzmann collision integral is represented as a divergence of the flow in velocity space. Owing to this, the role of collisions in the kinetic equation can be interpreted in terms of the nonlocal friction force that depends on the distribution function.

Electron stripping cross sections for light impurity ions in colliding with atomic hydrogens relevant to fusion research

International Nuclear Information System (INIS)

Tawara, H.

1992-04-01

Electron stripping (ionization) cross sections for impurity (carbon) ions with various charge states in collisions with atomic hydrogens have been surveyed. It has been found that these data are relatively limited both in collision energy and charge state and, in particular those necessary for high energy neutral beam injection (NBI) heating in fusion plasma research are scarce. Some relevant cross sections for carbon ions, C q+ (q = 0-5) have been estimated, based upon the existing data, empirical behavior and electron impact ionization data. (author)

The developments of international hydrogen and fuel cell technology standards and the response strategies in Taiwan

International Nuclear Information System (INIS)

Tso, C.

2009-01-01

The application of hydrogen and fuel cells has expanded as the technology in international markets has improved. Leading countries have focused on establishing hydrogen and fuel cell technology standards. Both the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) continuously release new hydrogen and fuel cell related standards. Although the government of Taiwan is promoting the development of a hydrogen and fuel cell industry, it may delay the commercialized schedule if there are no hydrogen and fuel cell related standards and regulations in place. Standards and regulations must be established as quickly as possible in order to accelerate the progress of the hydrogen and fuel cell industry. This presentation reviewed the international progress in hydrogen and fuel cell development and explained Taiwan's response strategies regarding the adoption of hydrogen and fuel cell products in niche Taiwanese markets

Electron-molecule collisions

International Nuclear Information System (INIS)

Shimamura, I.; Takayanagi, K.

1984-01-01

The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

Electron-capture cross sections for low-energy highly charged neon and argon ions from molecular and atomic hydrogen

International Nuclear Information System (INIS)

Can, C.; Gray, T.J.; Varghese, S.L.; Hall, J.M.; Tunnell, L.N.

1985-01-01

Electron-capture cross sections for low-velocity (10 6 --10 7 cm/s) highly charged Ne/sup q/+ (2< or =q< or =7) and Ar/sup q/+ (2< or =q< or =10)= projectiles incident on molecular- and atomic-hydrogen targets have been measured. A recoil-ion source that used the collisions of fast heavy ions (1 MeV/amu) with target gas atoms was utilized to produce slow highly charged ions. Atomic hydrogen was produced by dissociating hydrogen molecules in a high-temperature oven. Measurements and analysis of the data for molecular- and atomic-hydrogen targets are discussed in detail. The measured absolute cross sections are compared with published data and predictions of theoretical models

Absorption of hydrogen by vanadium-palladium alloys

International Nuclear Information System (INIS)

Artman, D.; Lynch, J.F.; Flanagan, T.B.

1976-01-01

Pressure composition isotherms (273-373 K) have been determined for the absorption of hydrogen by a series of six palladium alloys (f.c.c) in the composition range from 1 to 8 at.% vanadium. At a given hydrogen content, the equilibrium hydrogen pressure progressively increases with vanadium content. Thermodynamic parameters for the absorption of hydrogen are reported at infinite dilution of hydrogen and for the formation of the nonstoichiometric hydride from the hydrogen-saturated alloy. The relative, partial molar enthalpy of solution of hydrogen at infinite dilution increases slightly with vanadium content. The presence of vanadium, which absorbs hydrogen itself in its normal b.c.c. structure, greatly inhibits the ability of palladium to absorb hydrogen. For example, the isobaric solubility of hydrogen (1 atm, 298K) decreases from H/Pd=0.7 (palladium) to 0.024 (V(6%)-Pd). The lattice expansion due to the presence of interstitial hydrogen has been determined by X-ray diffraction. From these data it can be concluded that the formation of two non-stoichiometric hydride phases does not occur at vanadium contents greater that 5 at.% (298 K). Electrical resistance has been measured as a function of the hydrogen content of the alloys. The electrical resistance increases more markedly with hydrogen content for these alloys than for any of the palladium alloys previously examined. (Auth.)

Two-temperature equilibration in warm dense hydrogen measured with x-ray scattering from the LCLS

Science.gov (United States)

Fletcher, Luke; High Energy Density Sciences Collaboration

2017-10-01

Understanding the properties of warm dense hydrogen plasmas is critical for modeling stellar and planetary interiors, as well as for inertial confinement fusion (ICF) experiments. Of central importance are the electron-ion collision and equilibration times that determine the microscopic properties in a high energy density state. Spectrally and angularly resolved x-ray scattering measurements from fs-laser heated hydrogen have resolved the picosecond evolution and energy relaxation from a two-temperature plasma towards thermodynamic equilibrium in the warm dense matter regime. The interaction of rapidly heated cryogenic hydrogen irradiated by a 400 nm, 5x1017 W/cm2 , 70 fs-laser is visualized with ultra-bright 5.5 kev x-ray pulses from the Linac Coherent Light (LCLS) source in 1 Hz repetition rate pump-probe setting. We demonstrate that the energy relaxation is faster than many classical binary collision theories that use ad hoc cutoff parameters used in the Landau-Spitzer determination of the Coulomb logarithm. This work was supported by the DOE Office of Science, Fusion Energy Science under contract No. SF00515 and supported under FWP 100182 and DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division, contract DE-AC02-76SF00515.

Microscale Enhancement of Heat and Mass Transfer for Hydrogen Energy Storage

Energy Technology Data Exchange (ETDEWEB)

Drost, Kevin [Oregon State Univ., Corvallis, OR (United States); Jovanovic, Goran [Oregon State Univ., Corvallis, OR (United States); Paul, Brian [Oregon State Univ., Corvallis, OR (United States)

2015-09-30

The document summarized the technical progress associated with OSU’s involvement in the Hydrogen Storage Engineering Center of Excellence. OSU focused on the development of microscale enhancement technologies for improving heat and mass transfer in automotive hydrogen storage systems. OSU’s key contributions included the development of an extremely compact microchannel combustion system for discharging hydrogen storage systems and a thermal management system for adsorption based hydrogen storage using microchannel cooling (the Modular Adsorption Tank Insert or MATI).

Charge transfer in low-energy collisions of H with He+ and H+ with He in excited states

Science.gov (United States)

Loreau, J.; Ryabchenko, S.; Muñoz Burgos, J. M.; Vaeck, N.

2018-04-01

The charge transfer process in collisions of excited (n = 2, 3) hydrogen atoms with He+ and in collisions of excited helium atoms with H+ is studied theoretically. A combination of a fully quantum-mechanical method and a semi-classical approach is employed to calculate the charge-exchange cross sections at collision energies from 0.1 eV u‑1 up to 1 keV u‑1. These methods are based on accurate ab initio potential energy curves and non-adiabatic couplings for the molecular ion HeH+. Charge transfer can occur either in singlet or in triplet states, and the differences between the singlet and triplet spin manifolds are discussed. The dependence of the cross section on the quantum numbers n and l of the initial state is demonstrated. The isotope effect on the charge transfer cross sections, arising at low collision energy when H is substituted by D or T, is investigated. Rate coefficients are calculated for all isotopes up to 106 K. Finally, the impact of the present calculations on models of laboratory plasmas is discussed.

Hydrogen Fuel Cell: Research Progress and Near-Term Opportunities

Science.gov (United States)

2009-04-27

effort brings together automobile and ener- gy companies , as well as their suppliers and other stakeholders, to evaluate light-duty fuel cell vehicles...emissions compared to conventional power technologies. Grocers, banks, tire and hardware companies , logistics providers, and others in the private sector...Term Direct Hydrogen Proton Exchange Membrane (PEM) Fuel Cell Markets, April 2007. 2. Assumptions: Operate 7 hours/shift, 3 shifts/day, 7 days/week

Nucleus-Nucleus Collision as Superposition of Nucleon-Nucleus Collisions

International Nuclear Information System (INIS)

Orlova, G.I.; Adamovich, M.I.; Aggarwal, M.M.; Alexandrov, Y.A.; Andreeva, N.P.; Badyal, S.K.; Basova, E.S.; Bhalla, K.B.; Bhasin, A.; Bhatia, V.S.; Bradnova, V.; Bubnov, V.I.; Cai, X.; Chasnikov, I.Y.; Chen, G.M.; Chernova, L.P.; Chernyavsky, M.M.; Dhamija, S.; Chenawi, K.El; Felea, D.; Feng, S.Q.; Gaitinov, A.S.; Ganssauge, E.R.; Garpman, S.; Gerassimov, S.G.; Gheata, A.; Gheata, M.; Grote, J.; Gulamov, K.G.; Gupta, S.K.; Gupta, V.K.; Henjes, U.; Jakobsson, B.; Kanygina, E.K.; Karabova, M.; Kharlamov, S.P.; Kovalenko, A.D.; Krasnov, S.A.; Kumar, V.; Larionova, V.G.; Li, Y.X.; Liu, L.S.; Lokanathan, S.; Lord, J.J.; Lukicheva, N.S.; Lu, Y.; Luo, S.B.; Mangotra, L.K.; Manhas, I.; Mittra, I.S.; Musaeva, A.K.; Nasyrov, S.Z.; Navotny, V.S.; Nystrand, J.; Otterlund, I.; Peresadko, N.G.; Qian, W.Y.; Qin, Y.M.; Raniwala, R.; Rao, N.K.; Roeper, M.; Rusakova, V.V.; Saidkhanov, N.; Salmanova, N.A.; Seitimbetov, A.M.; Sethi, R.; Singh, B.; Skelding, D.; Soderstrem, K.; Stenlund, E.; Svechnikova, L.N.; Svensson, T.; Tawfik, A.M.; Tothova, M.; Tretyakova, M.I.; Trofimova, T.P.; Tuleeva, U.I.; Vashisht, Vani; Vokal, S.; Vrlakova, J.; Wang, H.Q.; Wang, X.R.; Weng, Z.Q.; Wilkes, R.J.; Yang, C.B.; Yin, Z.B.; Yu, L.Z.; Zhang, D.H.; Zheng, P.Y.; Zhokhova, S.I.; Zhou, D.C.

1999-01-01

Angular distributions of charged particles produced in 16 O and 32 S collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in proton-nucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleus-nucleus collisions can be seen as superposition of the angular distributions in nucleon-nucleus collisions taken at the same impact parameter b NA , that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus

Nucleus-Nucleus Collision as Superposition of Nucleon-Nucleus Collisions

Energy Technology Data Exchange (ETDEWEB)

Orlova, G I; Adamovich, M I; Aggarwal, M M; Alexandrov, Y A; Andreeva, N P; Badyal, S K; Basova, E S; Bhalla, K B; Bhasin, A; Bhatia, V S; Bradnova, V; Bubnov, V I; Cai, X; Chasnikov, I Y; Chen, G M; Chernova, L P; Chernyavsky, M M; Dhamija, S; Chenawi, K El; Felea, D; Feng, S Q; Gaitinov, A S; Ganssauge, E R; Garpman, S; Gerassimov, S G; Gheata, A; Gheata, M; Grote, J; Gulamov, K G; Gupta, S K; Gupta, V K; Henjes, U; Jakobsson, B; Kanygina, E K; Karabova, M; Kharlamov, S P; Kovalenko, A D; Krasnov, S A; Kumar, V; Larionova, V G; Li, Y X; Liu, L S; Lokanathan, S; Lord, J J; Lukicheva, N S; Lu, Y; Luo, S B; Mangotra, L K; Manhas, I; Mittra, I S; Musaeva, A K; Nasyrov, S Z; Navotny, V S; Nystrand, J; Otterlund, I; Peresadko, N G; Qian, W Y; Qin, Y M; Raniwala, R; Rao, N K; Roeper, M; Rusakova, V V; Saidkhanov, N; Salmanova, N A; Seitimbetov, A M; Sethi, R; Singh, B; Skelding, D; Soderstrem, K; Stenlund, E; Svechnikova, L N; Svensson, T; Tawfik, A M; Tothova, M; Tretyakova, M I; Trofimova, T P; Tuleeva, U I; Vashisht, Vani; Vokal, S; Vrlakova, J; Wang, H Q; Wang, X R; Weng, Z Q; Wilkes, R J; Yang, C B; Yin, Z B; Yu, L Z; Zhang, D H; Zheng, P Y; Zhokhova, S I; Zhou, D C

1999-03-01

Angular distributions of charged particles produced in {sup 16}O and {sup 32}S collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in proton-nucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleus-nucleus collisions can be seen as superposition of the angular distributions in nucleon-nucleus collisions taken at the same impact parameter b{sub NA}, that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus.

Nucleus-nucleus collision as superposition of nucleon-nucleus collisions

International Nuclear Information System (INIS)

Orlova, G.I.; Adamovich, M.I.; Aggarwal, M.M.

1999-01-01

Angular distributions of charged particles produced in 16 O and 32 S collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in proton-nucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleus-nucleus collisions can be seen as superposition of the angular distributions in nucleon-nucleus collisions taken at the same impact parameter b NA , that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus. (orig.)

A toolkit for integrated deterministic and probabilistic assessment for hydrogen infrastructure.

Energy Technology Data Exchange (ETDEWEB)

Groth, Katrina M.; Tchouvelev, Andrei V.

2014-03-01

There has been increasing interest in using Quantitative Risk Assessment [QRA] to help improve the safety of hydrogen infrastructure and applications. Hydrogen infrastructure for transportation (e.g. fueling fuel cell vehicles) or stationary (e.g. back-up power) applications is a relatively new area for application of QRA vs. traditional industrial production and use, and as a result there are few tools designed to enable QRA for this emerging sector. There are few existing QRA tools containing models that have been developed and validated for use in small-scale hydrogen applications. However, in the past several years, there has been significant progress in developing and validating deterministic physical and engineering models for hydrogen dispersion, ignition, and flame behavior. In parallel, there has been progress in developing defensible probabilistic models for the occurrence of events such as hydrogen release and ignition. While models and data are available, using this information is difficult due to a lack of readily available tools for integrating deterministic and probabilistic components into a single analysis framework. This paper discusses the first steps in building an integrated toolkit for performing QRA on hydrogen transportation technologies and suggests directions for extending the toolkit.

Canadian fuel cell commercialization roadmap update : progress of Canada's hydrogen and fuel cell industry

International Nuclear Information System (INIS)

Filbee, S.; Karlsson, T.

2009-01-01

Hydrogen and fuel cells are considered an essential part of future low-carbon energy systems for transportation and stationary power. In recognition of this, Industry Canada has worked in partnership with public and private stakeholders to provide an update to the 2003 Canadian Fuel Cell Commercialization Roadmap to determine infrastructure requirements for near-term markets. The update includes technology and market developments in terms of cost and performance. This presentation included an overview of global hydrogen and fuel cell markets as background and context for the activities of the Canadian industry. Approaches toward commercial viability and mass market success were also discussed along with possible scenarios and processes by which these mass markets could develop. Hydrogen and fuel cell industry priorities were outlined along with recommendations for building a hydrogen infrastructure

The Concept of Collision-Free Motion Planning Using a Dynamic Collision Map

Directory of Open Access Journals (Sweden)

Keum-Bae Cho

2014-09-01

Full Text Available In this paper, we address a new method for the collision-free motion planning of a mobile robot in dynamic environments. The motion planner is based on the concept of a conventional collision map (CCM, represented on the L(travel length-T(time plane. We extend the CCM with dynamic information about obstacles, such as linear acceleration and angular velocity, providing useful information for estimating variation in the collision map. We first analyse the effect of the dynamic motion of an obstacle in the collision region. We then define the measure of collision dispersion (MOCD. The dynamic collision map (DCM is generated by drawing the MOCD on the CCM. To evaluate a collision-free motion planner using the DCM, we extend the DCM with MOCD, then draw the unreachable region and deadlocked regions. Finally, we construct a collision-free motion planner using the information from the extended DCM.

Proceedings of the 2000 U.S. DOE Hydrogen Program Review

Energy Technology Data Exchange (ETDEWEB)

NREL

2000-11-01

The 2000 US Department of Energy (DOE) Hydrogen Program Review was sponsored by the Office of Power Delivery Systems, Office of Power Technologies, US Department of Energy. The proceedings from this meeting serve as an important technology reference for the DOE Hydrogen Program. This document contains technical progress reports on research and technology validation projects funded by the DOE Hydrogen Program in Fiscal Year 2000. The growth of fuel cell technology will provide a basis for the establishment of the hydrogen option into both transportation and electricity supply markets.

Negative meson capture in hydrogen

International Nuclear Information System (INIS)

Baird, T.J.

1977-01-01

The processes of deexcitation and capture of negative mesons and hadrons in atomic hydrogen are investigated. Only slow collisions in which the projectile-atom relative velocity is less than one atomic unit are considered, and the motion of the incident particle is treated classically. For each classical trajectory the probability of ionizing the hydrogen atom is determined, together with the energy spectrum of the emitted electron. Ionization probabilities are calculated using the time-dependent formulation of the perturbed stationary state method. Exact two-center electronic wave functions are used for both bound and continuum states. The total ionization cross section and electron energy spectrum have been calculated for negative muons, kaons and antiprotons at incident relative velocities between 0.04 and 1.0 atomic units. The electron energy spectrum has a sharp peak for electron kinetic energies on the order of 10 -3 Rydbergs. The ionization process thus favors the emission of very slow electrons. The cross section for ionization with capture of the incident particle was calculated for relative kinetic energies greater than 1.0 Rydberg. Since ionization was found to occur with the emission of electrons of nearly zero kinetic energy, the fraction of ionizing collisions which result in capture decreases very rapidly with projectile kinetic energy. The energy distributions of slowed down muons and hadrons were also computed. These distributions were used together with the capture cross section to determine the distribution of kinetic energies at which capture takes place. It was found that most captures occur for kinetic energies slightly less than 1.0 Rydbergs with relatively little capture at thermal energies. The captured particles therefore tend to go into very large and loosely found orbits with binding energies less than 0.1 Rydbergs

Electron capture in collisions of N^+ with H and H^+ with N

Science.gov (United States)

Lin, C. Y.; Stancil, P. C.; Gu, J. P.; Buenker, R. J.; Kimura, M.

2004-05-01

Charge transfer processes due to collisions of N^+ with atomic hydrogen and H^+ with atomic nitrogen are investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) method. The MOCC calculations utilize ab initio adiabatic potential curves and nonadiabatic radial and rotational coupling matrix elements obtained with the multireference single- and double-excitation configuration interaction approach. Total and state-selective cross sections for the energy range 0.1-500 eV/u will be presented and compared with existing experimental and theoretical data.

Progress of the ''batman'' RF source for negative hydrogen ions

International Nuclear Information System (INIS)

Frank, P.; Heinemann, B.; Kraus, W.; Probst, F.; Speth, E.; Vollmer, O.; Bucalossi, J.; Trainham, R.

1998-01-01

The aim of a collaboration between CEA Cadarache and IPP Garching is to investigate the ability of an rf source to produce negative-ion current densities compatible with ITER NBI requirements (20 mA/cm 2 D-). A standard PlNI-size rf source developed for ASDEX-Upgrade and a three-grid extraction system form the basis of BATMAN (Bavarian Test Machine for Negative Ions). In the case of a pure hydrogen plasma a current density of 5.5 mA/cm 2 at elevated pressure (2.4 Pa) can be reached. Adding small amounts of argon ( 2 . In the low pressure range (0.7 Pa) the negative ion yield is strongly reduced, but with an admixture of argon and a cesium injection the current density is higher approx. by a factor 8 (4 mA/cm 2 ) compared to the pure hydrogen discharge. The negative ion yield shows a saturation with increasing rf power. (author)

Study of heavy ions collision at SIS energies with the detector FOPI; Etude des collisions d'ions lourds aux energies de SIS avec le detecteur FOPI

Energy Technology Data Exchange (ETDEWEB)

Bastid, N

1999-09-23

The present work has been carried out in the framework of experiments performed with the FOPI detector at the SIS/ESR accelerator facility of GSI-Darmstadt. It is devoted to the study of central and semi-central heavy ion collisions at beam energies ranging from 100 MeV to 2 GeV per nucleon. We present first generalities on relativistic heavy ion collisions then the FOPI detector with a special attention to the FOPI Inner Wall constructed by the Clermont-Ferrand group. The main results of the FOPI collaboration obtained with light and intermediate mass fragments and kaons are presented. A systematic study of the different forms of collection motion of nuclear matter, radial flow in very central reactions, sideward flow and squeeze-out in semi-central collisions, is performed. Further exciting possibilities concerning production and propagation of strangeness at SIS energies will be offered soon with the upgrade of the FOPI detector. The FOPI data have introduced constraints on parameters of theoretical models. Important progress concerning the knowledge of the properties of nuclear matter, the dynamics of the collisions and in-medium effects have been achieved. (author)

Dynamical studies of molecular systems. Progress report, February 1, 1980-October 27, 1980

International Nuclear Information System (INIS)

Rabitz, H.

1980-01-01

Research was carried out in the general areas of collision dynamics and chemical kinetics. Research on the following topics was pursued: computational kinetics and sensitivity analysis of hydrogen-oxygen combustion; chemical kinetic functional sensitivity analysis, elementary sensitivities; the selective preparation of excited vibrational states using the stimulated resonance raman effect; an exactly soluble many channel scattering model; further developments and applications of sensitivity analysis to collisional energy transfer; sensitivity analysis of rotational energy transfer processes to the intermolecular potential; a review of vibrational rotational collision processes; sensitivity analysis of differential cross sections to the intermolecular potential; and a non-local formulation of inelastic scattering as a basis for practical approximations

Polyaniline as a material for hydrogen storage applications.

Science.gov (United States)

Attia, Nour F; Geckeler, Kurt E

2013-07-12

The main challenge of commercialization of the hydrogen economy is the lack of convenient and safe hydrogen storage materials, which can adsorb and release a significant amount of hydrogen at ambient conditions. Finding and designing suitable cost-effective materials are vital requirements to overcome the drawbacks of investigated materials. Because of its outstanding electronic, thermal, and chemical properties, the electrically conducting polyaniline (PANI) has a high potential in hydrogen storage applications. In this review, the progress in the use of different structures of conducting PANI, its nanocomposites as well as activated porous materials based on PANI as hydrogen storage materials is presented and discussed. The effect of the unique electronic properties based on the π-electron system in the backbone of these materials in view of the hydrogen uptake and the relevant mechanisms are highlighted. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1981-01-01

Qualitative picture of high energy hadron-nucleus collision process, emerging from the analysis of experimental data, is presented. Appropriate description procedure giving a possibility of reproducing various characteristics of this process in terms of the data on elementary hadron-nucleon interaction is proposed. Formula reproducing hadron-nucleus collision cross sections is derived. Inelastic collision cross sections for pion-nucleus and proton-nucleus reactions at wide energy interval are calculated for Pb, Ag, and Al targets. A-dependence of cross sections for pion-nucleus and proton-nucleus collisions at nearly 50 GeV/c momentum were calculated and compared with existing experimental data. Energy dependence of cross sections for hadron-nucleus collisions is determined simply by energy dependence of corresponding cross sections for hadron-nucleon collisions; A-dependence is determined simply by nuclear sizes and nucleon density distributions in nuclei

Hypothesis for the mechanism of negative ion production in the surface-plasma negative hydrogen ion source

International Nuclear Information System (INIS)

Hiskes, J.R.

1975-01-01

An analysis of the surface-plasma negative hydrogen ion source has shown that the tungsten cathode supports approximately a monolayer of cesium. The backscattering of protons from the cathode as energetic neutrals and the subsequent backscattering of these neutrals from the anode provides for a flux of energetic atoms incident upon the cathode which is comparable to the ion flux. A hypothesis is proposed for the generation of negative ions during the collision of these energetic atoms with the cathode. Several mechanisms for negative ion production by proton collision with the surface are discussed. (U.S.)

Proceedings of the 1998 U.S. DOE Hydrogen Program Review: Volume 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-08-01

This document contains technical progress reports on 42 research projects funded by the DOE Hydrogen Program in Fiscal Year 1998, in support of its mission to make hydrogen a cost-effective energy carrier for utility, building, and transportation applications. Each year, the Program conducts a rigorous review of its portfolio of projects, utilizing teams of experts to provide vital feedback on the progress of research. These proceedings serve as an important technology reference for the DOE Hydrogen Program. The papers in Volume 2 are arranged under the following topical sections: Storage and separation systems; Thermal systems; and Transportation systems. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

Restricted Collision List method for faster Direct Simulation Monte-Carlo (DSMC) collisions

Energy Technology Data Exchange (ETDEWEB)

Macrossan, Michael N., E-mail: m.macrossan@uq.edu.au

2016-08-15

The ‘Restricted Collision List’ (RCL) method for speeding up the calculation of DSMC Variable Soft Sphere collisions, with Borgnakke–Larsen (BL) energy exchange, is presented. The method cuts down considerably on the number of random collision parameters which must be calculated (deflection and azimuthal angles, and the BL energy exchange factors). A relatively short list of these parameters is generated and the parameters required in any cell are selected from this list. The list is regenerated at intervals approximately equal to the smallest mean collision time in the flow, and the chance of any particle re-using the same collision parameters in two successive collisions is negligible. The results using this method are indistinguishable from those obtained with standard DSMC. The CPU time saving depends on how much of a DSMC calculation is devoted to collisions and how much is devoted to other tasks, such as moving particles and calculating particle interactions with flow boundaries. For 1-dimensional calculations of flow in a tube, the new method saves 20% of the CPU time per collision for VSS scattering with no energy exchange. With RCL applied to rotational energy exchange, the CPU saving can be greater; for small values of the rotational collision number, for which most collisions involve some rotational energy exchange, the CPU may be reduced by 50% or more.

Research Progress of Hydrogen Production fromOrganic Wastes in Microbial Electrolysis Cell(MEC

Directory of Open Access Journals (Sweden)

YU Yin-sheng

2015-08-01

Full Text Available Microbial electrolysis cell(MECtechnology as an emerging technology, has achieved the target of hydrogen production from different substrates such as waste water, forestry wastes, activated sludge by simultaneous enzymolysis and fermentation, which can effectively improve the efficiency of resource utilization. This paper described the working principle of MEC and analyzed these factors influencing the process of hydrogen production from organic waste in MEC.

Electron capture by Ne3+ ions from atomic hydrogen

International Nuclear Information System (INIS)

Rejoub, R.; Bannister, M.E.; Havener, C.C.; Savin, D.W.; Verzani, C.J.; Wang, J.G.; Stancil, P.C.

2004-01-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne 3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u. Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u. Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ∼1 eV/u, an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ∼4 eV/u, the present calculations show a significant target isotope effect

Electron capture by Ne3+ ions from atomic hydrogen

Science.gov (United States)

Rejoub, R.; Bannister, M. E.; Havener, C. C.; Savin, D. W.; Verzani, C. J.; Wang, J. G.; Stancil, P. C.

2004-05-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u . Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u . Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ˜1 eV/u , an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ˜4 eV/u , the present calculations show a significant target isotope effect.

Jet and Leading Hadron Production in High-energy Heavy-ion Collisions

International Nuclear Information System (INIS)

Wang, Xin-Nian

2005-01-01

Jet tomography has become a powerful tool for the study of properties of dense matter in high-energy heavy-ion collisions. I will discuss recent progresses in the phenomenological study of jet quenching, including momentum, colliding energy and nuclear size dependence of single hadron suppression, modification of dihadron correlations and the soft hadron distribution associated with a quenched jet

The cost analysis of hydrogen life cycle in China

International Nuclear Information System (INIS)

Yao, Fei; Jia, Yuan; Mao, Zongqiang

2010-01-01

Currently, the increasing price of oil and the possibility of global energy crisis demand for substitutive energy to replace fossil energy. Many kinds of renewable energy have been considered, such as hydrogen, solar energy, and wind energy. Many countries including China have their own plan to support the research of hydrogen, because of its premier features. But, at present, the cost of hydrogen energy production, storage and transportation process is higher than that of fossil energy and its commercialization progress is slow. Life cycle cost analysis (LCCA) was used in this paper to evaluate the cost of hydrogen energy throughout the life cycle focused on the stratagem selection, to demonstrate the costs of every step and to discuss their relationship. Finally, the minimum cost program is as follows: natural gas steam reforming - high-pressure hydrogen bottles transported by car to hydrogen filling stations - hydrogen internal-combustion engines. (author)

The populations of excited levels of hydrogen-like and helium-like ions in plasmas traversed by neutral hydrogen beams

International Nuclear Information System (INIS)

Spence, J.; Summers, H.P.

1985-01-01

This paper examines the populations of levels of impurity ions in a spartially homogeneous plasma containing primarily thermal electrons and protons and monoenergetic neutral hydrogen atoms. Of special concern is the role of recombination which may include the radiative, three-body and dielectronic process together with charge exchange capture from neutral hydrogen beams. The influence of these primary processes on the population is modified by radiative transitions and redistributive transitions due to collisions with electrons and protons in the plasma. The behaviour of the populations of the ions C 5+ , C 4+ and Ar 16+ with variation of plasma parameters is explored in the present work. A bundled principal quantum level picture and a more elaborate LS resolved picture are used which allow investigation of the expected spectral emission and its sensitivity to uncertainty in the primary rates. The variation of the impurity ion spectrum in transiently recombining or ionising conditions is also considered. (orig.)

Progress in the Development of Lightweight Nickel Electrode for Nickel-Hydrogen Cell

Science.gov (United States)

Britton, Doris L.

1999-01-01

Development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (Ni-H2) program at the NASA Glenn Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a lighter weight electrode for the nickel-hydrogen cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active material. Initial tests include activation and capacity measurements at five different discharge levels, C/2, 1.0 C, 1.37 C, 2.0 C, and 2.74 C. The electrodes are life cycle tested using a half-cell configuration at 40 and 80% depths-of-discharge (DOD) in a low-Earth-orbit regime. The electrodes that pass the initial tests are life cycle-tested in a boiler plate nickel-hydrogen cell before flight weight design are built and tested.

Full two-electron calculations of antiproton collisions with molecular hydrogen

DEFF Research Database (Denmark)

Lühr, Armin Christian; Saenz, Alejandro

2010-01-01

Total cross sections for single ionization and excitation of molecular hydrogen by antiproton impact are presented over a wide range of impact energies from 1 keV to 6.5 MeV. A nonperturbative time-dependent close-coupling method is applied to fully treat the correlated dynamics of the electrons....... Good agreement is obtained between the present calculations and experimental measurements of single-ionization cross sections at high energies, whereas some discrepancies with the experiment are found around the maximum. The importance of the molecular geometry and a full two-electron description...... is demonstrated. The present findings provide benchmark results which might be useful for the development of molecular models....

Self-consistent collisional-radiative model for hydrogen atoms: Atom–atom interaction and radiation transport

International Nuclear Information System (INIS)

Colonna, G.; Pietanza, L.D.; D’Ammando, G.

2012-01-01

Graphical abstract: Self-consistent coupling between radiation, state-to-state kinetics, electron kinetics and fluid dynamics. Highlight: ► A CR model of shock-wave in hydrogen plasma has been presented. ► All equations have been coupled self-consistently. ► Non-equilibrium electron and level distributions are obtained. ► The results show non-local effects and non-equilibrium radiation. - Abstract: A collisional-radiative model for hydrogen atom, coupled self-consistently with the Boltzmann equation for free electrons, has been applied to model a shock tube. The kinetic model has been completed considering atom–atom collisions and the vibrational kinetics of the ground state of hydrogen molecules. The atomic level kinetics has been also coupled with a radiative transport equation to determine the effective adsorption and emission coefficients and non-local energy transfer.

Slow Collisions of Si3+ with Atomic Hydrogen

Science.gov (United States)

Joseph, D. C.; Gu, J.-P.; Saha, B. C.; Liebermann, H. P.; Funke, P.; Buenker, R. J.

2010-03-01

Low energy electron capture from hydrogen atom by multi-charged ions continues to be of interest and applications include both magnetically confined fusion and astrophysical plasmas. The charge exchange process reported here, Si^3+ + H -> Si^2+ + H^+ is an important destruction mechanism of Si^3+ in photo-ionized gas. The soft X-ray emission from comets has been explained by charge transfer of solar wind ions, among them Si^3+, with neutrals in the cometary gas vapor. The state selective cross sections are evaluated using the full quantum [1] and semi-classical molecular orbital close coupling (MOCC) [2] methods. Adiabatic potentials and wave functions for a number of low-lying singlet and triplet states of and symmetry are calculated wing the MRD-CI package [3]. Details will be presented at the conference. [4pt] [1] L. B. Zhao, D. C. Joseph, B. C. Saha, H. P. Liebermann, P. Funke and R. J. Buenker, Phys. Rev A, 79, 034701 (1009).[0pt] [2] M. Kimura and N. F. Lane, At. Mol. Opt. Phys 26, 79 (1990).[0pt] [3] R. J. Buenker, ``Current Aspects of Quantum Chemistry 1981, Vol 21, edited by R. Carbo (Elsevier, Amsterdam) p 17.

Study of dissociative collisions of hydrogen-line ions by mean of angular and energy distributions

International Nuclear Information System (INIS)

Martinez, H.; Urquijo, J. de; Cisneros, C.; Alvarez, J.

1988-01-01

Angular and energy distribution of fragments produced in a collision, employed in conjunction with the 'step-model' that means excitation and binary dissociation, are used to determine the binding energy of H 3 (D 3 ) and HD + 2 and also to identify the principal channels in the dissociation processes. (A.C.A.S.) [pt

Ion-ion collisions

International Nuclear Information System (INIS)

Salzborn, Erhard; Melchert, Frank

2000-01-01

Collisions between ions belong to the elementary processes occurring in all types of plasmas. In this article we give a short overview about collisions involving one-electron systems. For collisions involving multiply-charged ions we limit the discussion to one specific quasi-one-electron system. (author)

The solar-hydrogen economy: an analysis

Science.gov (United States)

Reynolds, Warren D.

2007-09-01

The 20th Century was the age of the Petroleum Economy while the 21st Century is certainly the age of the Solar-Hydrogen Economy. The global Solar-Hydrogen Economy that is now emerging follows a different logic. Under this new economic paradigm, new machines and methods are once again being developed while companies are restructuring. The Petroleum Economy will be briefly explored in relation to oil consumption, Hubbert's curve, and oil reserves with emphasis on the "oil crash". Concerns and criticisms about the Hydrogen Economy will be addressed by debunking some of the "hydrogen myths". There are three major driving factors for the establishment of the Solar-Hydrogen Economy, i.e. the environment, the economy with the coming "oil crash", and national security. The New Energy decentralization pathway has developed many progressive features, e.g., reducing the dependence on oil, reducing the air pollution and CO II. The technical and economic aspects of the various Solar-Hydrogen energy options and combinations will be analyzed. A proposed 24-hour/day 200 MWe solar-hydrogen power plant for the U.S. with selected energy options will be discussed. There are fast emerging Solar Hydrogen energy infrastructures in the U.S., Europe, Japan and China. Some of the major infrastructure projects in the transportation and energy sectors will be discussed. The current and projected growth in the Solar-Hydrogen Economy through 2045 will be given.

Inductively coupled plasma mass spectrometry with hexapole collision cell: figures of merit and applications

Energy Technology Data Exchange (ETDEWEB)

Boulyga, S.F. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen]|[Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen

2000-11-01

The use of gas-filled multipole collision cells represents important progress in ICP-MS instrumentation. It enables an increase in element sensitivity based on the improvement of ion transmission efficiency from near thermalization and collisional focusing of ions. In addition, gas-phase ion-molecule chemistry can be applied in order to reduce mass spectral interferences via charge transfer reaction of interfering ions with reaction gas or via fragmentation of interfering molecular ions by collision-induced dissociation. The application of a hexapole collision cell in quadrupole based ICP-MS (HEX-ICP-QMS) was studied systematically in order to characterize the analytical figures of merit of this approach. Additionally, the performance of different solution introduction systems as well as an inductively coupled plasma shielded torch was studied for use with HEX-ICP-QMS. (orig.)

Catalytic hydrogenation of carbon monoxide. Progress report, December 15, 1991--December 14, 1992

Energy Technology Data Exchange (ETDEWEB)

Wayland, B.B.

1992-12-01

This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

e+e- collisions at the SLC--the left-right asymmetry

International Nuclear Information System (INIS)

Prescott, C.Y.

1993-09-01

Recent progress with the SLC as a prototype linear collider for high energy e + e - collisions is reviewed. Recent advances in the production of high intensity beams of polarized e -s are also discussed. The SLD Collaboration has embarked on a precision measurement of the left-right polarization asymmetry A LR at the Z pole with polarized electrons. Results and future plans are presented

The United Kingdom Hydrogen Association Forms with International Collaboration in Mind

International Nuclear Information System (INIS)

Karen Hall; John Carolin; Ian Williamson

2006-01-01

In April 2006, the United Kingdom Hydrogen Association was launched. This paper will describe the context under which the need was established, and address the challenges and opportunities faced in creating the association. A UK Hydrogen Association can encourage information sharing among regional hydrogen efforts, and provide a mechanism for a larger, single voice on the national level. In addition, a UK Hydrogen Association can serve as a focal point for UK participation in EU activities such as the European Hydrogen and Fuel Cell Technology Platform (HFP), and other international activities such as IPHE and IEA. The results of the stakeholder briefing and progress of a UK Hydrogen Association will be presented, with a focus on international collaboration. (authors)

The atomic hydrogen cloud in the saturnian system

Science.gov (United States)

Tseng, W.-L.; Johnson, R. E.; Ip, W.-H.

2013-09-01

The importance of Titan's H torus shaped by solar radiation pressure and of hydrogen atoms flowing out of Saturn's atmosphere in forming the broad hydrogen cloud in Saturn's magnetosphere is still debated. Since the Saturnian system also contains a water product torus which originates from the Enceladus plumes, the icy ring particles, and the inner icy satellites, as well as Titan's H2 torus, we have carried out a global investigation of the atomic hydrogen cloud taking into account all sources. We show that the velocity and angle distributions of the hot H ejected from Saturn's atmosphere following electron-impact dissociation of H2 are modified by collisions with the ambient atmospheric H2 and H. This in turn affects the morphology of the escaping hydrogen from Saturn, as does the morphology of the ionospheric electron distribution. Although an exact agreement with the Cassini observations is not obtained, our simulations show that H directly escaping from Titan is the dominant contributor in the outer magnetosphere. Of the total number of H observed by Cassini from 1 to 5RS, ∼5.7×1034, our simulations suggest ∼20% is from dissociation in the Enceladus torus, ∼5-10% is from dissociation of H2 in the atmosphere of the main rings, and ∼50% is from Titan's H torus, implying that ∼20% comes from Saturn atmosphere.

Hydrogen related safety issues in the context of containments of Indian PHWRs

International Nuclear Information System (INIS)

Markendeya, S.G.; Ghosh, A.K.; Kushwaha, H.S.; Venkat Raj, V.

2002-01-01

Full text: Assessment of risk due to hydrogen released during postulated hypothetical accident scenarios in the nuclear power plants (NPPs) has been an important area of R and D studies world over. The issues, such as appropriate methodologies for estimation of hydrogen source term and for hydrogen dispersion calculations, technology development for hydrogen mitigation in containment of NPPs and assessment of damage due to deflagration/detonation of hydrogen (if it occurs) are being addressed as a part of some of the multidisciplinary study programs currently underway in BARC. While a significant overall progress has been achieved in general as a result of these programs, requirements of further fine-tuning of these studies have also emerged. The present paper takes a brief look at the current state-of the-art technology available to address these issues. The progress of R and D studies underway at BARC has also been critically reviewed in the paper to bring out necessary planning of further studies so as to enhance the safety of Indian NPPs

Collision-induced absorption with exchange effects and anisotropic interactions: theory and application to H2 - H2.

Science.gov (United States)

Karman, Tijs; van der Avoird, Ad; Groenenboom, Gerrit C

2015-02-28

We discuss three quantum mechanical formalisms for calculating collision-induced absorption spectra. First, we revisit the established theory of collision-induced absorption, assuming distinguishable molecules which interact isotropically. Then, the theory is rederived incorporating exchange effects between indistinguishable molecules. It is shown that the spectrum can no longer be written as an incoherent sum of the contributions of the different spherical components of the dipole moment. Finally, we derive an efficient method to include the effects of anisotropic interactions in the computation of the absorption spectrum. This method calculates the dipole coupling on-the-fly, which allows for the uncoupled treatment of the initial and final states without the explicit reconstruction of the many-component wave functions. The three formalisms are applied to the collision-induced rotation-translation spectra of hydrogen molecules in the far-infrared. Good agreement with experimental data is obtained. Significant effects of anisotropic interactions are observed in the far wing.

Scaling relations in elastic scattering cross sections between multiply charged ions and hydrogen

International Nuclear Information System (INIS)

Rodriguez, V.D.

1991-01-01

Differential elastic scattering cross sections of bare ions from hydrogen are calculated using the eikonal approximation. The results satisfy a scaling relation involving the scattering angle, the ion charge and a factor related to the ion mass. A semiclassical explanation in terms of a distant collision hypothesis for small scattering angle is proposed. A unified picture of related scaling rules found in direct processes is discussed. (author)

Glauber amplitudes for transitions from low lying states in hydrogen atom by charged particle impact

Energy Technology Data Exchange (ETDEWEB)

Kumar, S; Srivastava, M K [Roorkee Univ. (India). Dept. of Physics

1977-07-01

The Glauber amplitudes for the general transition nlm ..-->.. n'1'm' in charged particle - hydrogen atom collisions have been obtained in the form of a one-dimensional integral. The final expression involves only a few hypergeometric functions if n is not too large and is particularly suited to study excitation to highly excited states from a low lying state.

Cross section measurements of the processes occurring in the fragmentation of Hn+ (3 ≤ n ≤ 35) hydrogen clusters induced by high speed (60 keV/u) collisions on helium atoms

International Nuclear Information System (INIS)

Louc, Sandrine

1997-01-01

Different processes involved in the fragmentation of ionised hydrogen clusters H 3 + (H 2 ) (n-3)/2 (n = 5-35) have been studied in the same experiment: the fragmentation of the cluster is induced by the collision with an helium atom at high velocity (≅ c/100). The collision is realised in reversed kinematic - clusters are accelerated - which allows the detection of neutral and charged fragments. The different channels of fragmentation are identified by using coincidence techniques. For all the cluster sizes studied the capture cross sections of one electron of the target by the cluster is equal to the capture cross section of the H 3 + ion. In the same way, the dissociation cross section of the H 3 + core of the cluster does not depend on cluster size. These fragmentation processes are due to the interaction of H 3 + core of the cluster and the helium atom without ionization of another component of the cluster. On the contrary, the cross sections of loss of one, two and three molecules by the cluster and the dissociation cross section of the cluster in all its molecular components depends strongly on the cluster size. This dependence is different from the one measured for the metastable decay of the cluster. Thus, the process of loss of molecules induced by a collision should correspond to a different dissociation mechanism. In regard of the singularities observed for the size dependence, the H 9 + , H 15 + , H 19 + and H 29 + clusters could be the 'core' of the biggest clusters. These observation are in agreement with the size effects of smaller magnitude observed for the dissociation cross section (all the processes). The values of the cross section for the process of at least one ionization of the cluster indicate that about 80% of the fragmentation events result from this process. (author)

Hydrogen adsorption on partially oxidised microporous carbons

International Nuclear Information System (INIS)

J B Parra; C O Ania; C J Duran Valle; M L Sanchez; C Otero Arean

2005-01-01

The search for cost effective adsorbents for large scale gas separation, storage and transport constitutes a present day strategic issue in the energy sector, propelled mainly by the potential use of hydrogen as an energy vector in a sustainable (and cleaner) energy scenario. Both, activated carbons and carbon based nano-structured materials have been proposed as potential candidates for reversible hydrogen storage in cryogenically cooled vessels. For that purpose, surface modification so as to enhance the gas solid interaction energy is desirable. We report on hydrogen adsorption on microporous (active) carbons which have been partially oxidised with nitric acid and ammonium persulfate. From the corresponding hydrogen adsorption isotherms (Fig. 1) an isosteric heat of about 3 kJ mol -1 was derived. This value is in agreement with that of about 3 to 4 kJ mol -1 obtained by quantum chemical calculations on the interaction between the hydrogen molecule and simple model systems (Fig. 2) of both, hydroxyl and carboxyl groups. Further research is in progress with a view to further increases the gas solid interaction energy. However, the values so far obtained are significantly larger than the liquefaction enthalpy of hydrogen: 0.90 kJ mol -1 ; and this is relevant to both, hydrogen separation from gas mixtures and cryogenic hydrogen storage. (authors)

The Norwegian hydrogen guide 2010

Energy Technology Data Exchange (ETDEWEB)

2010-07-01

Hydrogen technologies are maturing at rapid speed, something we experience in Norway and around the globe every day as demonstration projects for vehicles and infrastructure expand at a rate unthinkable of only a few years ago. An example of this evolution happened in Norway in 2009 when two hydrogen filling stations were opened on May the 11th, making it possible to arrange the highly successful Viking Rally from Oslo to Stavanger with more than 40 competing teams. The Viking Rally demonstrated for the public that battery and hydrogen-electric vehicles are technologies that exist today and provide a real alternative for zero emission mobility in the future. The driving range of the generation of vehicles put into demonstration today is more than 450 km on a full hydrogen tank, comparable to conventional vehicles. As the car industry develops the next generation of vehicles for serial production within the next 4-5 years, we will see vehicles that are more robust, more reliable and cost effective. Also on the hydrogen production and distribution side progress is being made, and since renewable hydrogen from biomass and electrolysis is capable of making mobility basically emission free, hydrogen can be a key component in combating climate change and reducing local emissions. The research Council of Norway has for many years supported the development of hydrogen and fuel cell technologies, and The Research Council firmly believes that hydrogen and fuel cell technologies play a crucial role in the energy system of the future. Hydrogen is a flexible transportation fuel, and offers possibilities for storing and balancing intermittent electricity in the energy system. Norwegian companies, research organisations and universities have during the last decade developed strong capabilities in hydrogen and fuel cell technologies, capabilities it is important to further develop so that Norwegian actors can supply high class hydrogen and fuel cell technologies to global markets

The development and validation of a new collision processor for MONK

International Nuclear Information System (INIS)

Connolly, Simon; Grimstone, Malcolm

2003-01-01

This paper summarises the progress with a major development project for the MONK Monte Carlo criticality code, namely the development of a new collision processing modelling package and nuclear data library. The development has now reached the final validation stage and further results will become available over the coming months in the period leading up the release of MONK9. (J.P.N.)

Quantum dynamics of hydrogen atoms on graphene. II. Sticking

Energy Technology Data Exchange (ETDEWEB)

Bonfanti, Matteo, E-mail: matteo.bonfanti@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano (Italy); Jackson, Bret [Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Hughes, Keith H. [School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW (United Kingdom); Burghardt, Irene [Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main (Germany); Martinazzo, Rocco, E-mail: rocco.martinazzo@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano (Italy); Istituto di Scienze e Tecnologie Molecolari, Consiglio Nazionale delle Richerche, v. Golgi 19, 20133 Milano (Italy)

2015-09-28

Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

Quantum dynamics of hydrogen atoms on graphene. II. Sticking

Science.gov (United States)

Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H.; Burghardt, Irene; Martinazzo, Rocco

2015-09-01

Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (˜0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

Quantum dynamics of hydrogen atoms on graphene. II. Sticking.

Science.gov (United States)

Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H; Burghardt, Irene; Martinazzo, Rocco

2015-09-28

Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

Quantum dynamics of hydrogen atoms on graphene. II. Sticking

International Nuclear Information System (INIS)

Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H.; Burghardt, Irene; Martinazzo, Rocco

2015-01-01

Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated

2010 Hydrogen and Fuel Cell Global Commercialization & Development Update

Energy Technology Data Exchange (ETDEWEB)

none,

2010-11-01

This report offers examples of real-world applications and technical progress of hydrogen and fuel cell technologies, including policies adopted by countries to increase technology development and commercialization.

Geothermal hydrogen - a vision? Paper

Energy Technology Data Exchange (ETDEWEB)

Zittel, W.; Weindorf, W.; Wurster, R.; Bussmann, W.

2001-07-01

With the progresses in geothermal electricity production by means of the hot-dry-rock (HDR) method electricity might be produced at cost of between 0.07 - 0.09 ECU/kWh, depending on systems sizes of between 5 - 20 MW{sub e}. The electricity can be used to produce hydrogen from electrolysis and water. This method of electricity production offers high availability with operating hour of between 7,600 - 8,000 hours per year. The 40 GWh electricity production per year from one 5 MW{sub e} geothermal plant are sufficient to produce enough hydrogen for the operation of an average fueling station with about 400 refuelings per day at cost of about 20 - 30 percent higher than today's gasoline (including taxes). In this contribution some details of the analysis are presented as well as a general discussion of geothermal hydrogen production as a future energy vector. (orig.)

Probability of satellite collision

Science.gov (United States)

Mccarter, J. W.

1972-01-01

A method is presented for computing the probability of a collision between a particular artificial earth satellite and any one of the total population of earth satellites. The collision hazard incurred by the proposed modular Space Station is assessed using the technique presented. The results of a parametric study to determine what type of satellite orbits produce the greatest contribution to the total collision probability are presented. Collision probability for the Space Station is given as a function of Space Station altitude and inclination. Collision probability was also parameterized over miss distance and mission duration.

Separation and identification of structural isomers by quadrupole collision-induced dissociation-hydrogen/deuterium exchange-infrared multiphoton dissociation (QCID-HDX-IRMPD).

Science.gov (United States)

Gucinski, Ashley C; Somogyi, Arpád; Chamot-Rooke, Julia; Wysocki, Vicki H

2010-08-01

A new approach that uses a hybrid Q-FTICR instrument and combines quadrupole collision-induced dissociation, hydrogen-deuterium exchange, and infrared multiphoton dissociation (QCID-HDX-IRMPD) has been shown to effectively separate and differentiate isomeric fragment ion structures present at the same m/z. This method was used to study protonated YAGFL-OH (free acid), YAGFL-NH(2) (amide), cyclic YAGFL, and YAGFL-OCH(3) (methyl ester). QCID-HDX of m/z 552.28 (C(29)H(38)N(5)O(6)) from YAGFL-OH reveals at least two distributions of ions corresponding to the b(5) ion and a non-C-terminal water loss ion structure. Subsequent IRMPD fragmentation of each population shows distinct fragmentation patterns, reflecting the different structures from which they arise. This contrasts with data for YAGFL-NH(2) and YAGFL-OCH(3), which do not show two distinct H/D exchange populations for the C(29)H(38)N(5)O(6) structure formed by NH(3) and HOCH(3) loss, respectively. Relative extents of exchange for C(29)H(38)N(5)O(6) ions from six sequence isomers (YAGFL, AGFLY, GFLYA, FLYAG, LYAGF, and LFGAY) show a sequence dependence of relative isomer abundance. Supporting action IRMPD spectroscopy data are also presented herein and also show that multiple structures are present for the C(29)H(38)N(5)O(6) species from YAGFL-OH. Copyright 2010. Published by Elsevier Inc.

The United Kingdom Hydrogen Association Forms with International Collaboration in Mind

International Nuclear Information System (INIS)

Karen Hall; John Carolin; Ian Williamson

2006-01-01

In April 2006, the United Kingdom Hydrogen Association was launched. This paper will describe the context under which the need was established, and address the challenges and opportunities faced in creating the association. A UK Hydrogen Association can encourage information sharing among regional hydrogen efforts, and provide a mechanism for a larger, single voice on the national level. In addition, a UK Hydrogen Association can serve as a focal point for UK participation in EU activities such as the European Hydrogen and Fuel Cell Technology Platform (HFP), and other international activities such as IPHE and IEA. The results of the stake holder briefing and progress of a UK Hydrogen Association will be presented, with a focus on international collaboration. (authors)

An Experimental Study of Unconfined Hydrogen/Oxygen and Hydrogen/Air Explosions

Science.gov (United States)

Richardson, Erin; Skinner, Troy; Blackwood, James; Hays, Michael; Bangham, Mike; Jackson, Austin

2014-01-01

Development tests are being conducted to characterize unconfined Hydrogen/air and Hydrogen/Oxygen blast characteristics. Most of the existing experiments for these types of explosions address contained explosions, like shock tubes. Therefore, the Hydrogen Unconfined Combustion Test Apparatus (HUCTA) has been developed as a gaseous combustion test device for determining the relationship between overpressure, impulse, and flame speed at various mixture ratios for unconfined reactions of hydrogen/oxygen and hydrogen/air. The system consists of a central platform plumbed to inject and mix component gasses into an attached translucent bag or balloon while monitoring hydrogen concentration. All tests are ignited with a spark with plans to introduce higher energy ignition sources in the future. Surrounding the platform are 9 blast pressure "Pencil" probes. Two high-speed cameras are used to observe flame speed within the combustion zone. The entire system is raised approx. 6 feet off the ground to remove any ground reflection from the measurements. As of this writing greater than 175 tests have been performed and include Design of Experiments test sets. Many of these early tests have used bags or balloons between approx. 340L and approx. 1850L to quantify the effect of gaseous mixture ratio on the properties of interest. All data acquisition is synchronized between the high-speed cameras, the probes, and the ignition system to observe flame and shock propagation. Successful attempts have been made to couple the pressure profile with the progress of the flame front within the combustion zone by placing a probe within the bag. Overpressure and impulse data obtained from these tests are used to anchor engineering analysis tools, CFD models and in the development of blast and fragment acceleration models.

Carbon and hydrogen matabolism of green algae in light and dark: Final report

Energy Technology Data Exchange (ETDEWEB)

Gibbs, M. [Brandeis Univ., Waltham, MA (United States), Department of Biology

1996-12-31

This report provides an overview of the progress made during this study. Progress is reported in chloroplast respiration, photoregulation of chloroplast respiration, reductive carboxylic acid cycle, and in oxy-hydrogen reaction all in Chlamydomonas.

Correlated charge-changing ion-atom collisions

International Nuclear Information System (INIS)

Tanis, J.A.

1992-04-01

This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from March 16, 1991 through March 15, 1992. This work involves the experimental investigation of fundamental atomic processes in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron correlation effects. Processes involving combinations of excitation, ionization, and charge transfer are investigated utilizing coincidence techniques in which projectiles charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. New results have been obtained for studies involving (1) resonant recombination of atomic ions, (2) double ionization of helium, and (3) continuum electron emission. Experiments were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, Michigan State University, Western Michigan University, and the Institute of Nuclear Research, Debrecen, Hungary. Brief summaries of work completed and work in progress are given in this report

Correlated charge changing ion-atom collisions

International Nuclear Information System (INIS)

Bernstein, E.M.; Tanis, J.A.

1990-02-01

This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant FG02-87ER13778 from August 15, 1987 through February 15, 1990. The general scope of this work involves the experimental investigation of fundamental atomic interactions in collisions of highly charged projectiles with neutral targets, with a particular emphasis on two-electron interactions. Inner-shell processes involving excitation, ionization, and charge transfer are investigated using, for the most part, coincidence techniques in which projectile charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. Measurements were conducted using accelerators at the Lawrence Berkeley Laboratory (LBL), Argonne National Laboratory (ANL), Hahn-Meitner-Institut, Berlin (HMI), and Western Michigan University (WMU). The research described here has resulted in 34 published papers, 14 invited presentations at national and international meetings, and 31 contributed presentations. Brief summaries of work completed and work in progress are discussed in this paper

Progress of scientific researches and project of CSR in IMP

International Nuclear Information System (INIS)

Jin Genming

2004-01-01

The article reviews the recent progress of the scientific researches including synthesis of new nuclides, investigations of the isospin effects in heavy ion collisions, studies of the nuclear structure in high spin states and the applications of heavy ion beams to other scientific researches, such as biology and material science. It also gives a brief introduction of the development of the design and progress of the new project of heavy ion cooling storage ring (CSR) of Lanzhou. (author)

Evidence for collective expansion in light-particle emission following Au+Au collisions at 100, 150 and 250 A·MeV

Science.gov (United States)

Poggi, G.; Pasquali, G.; Bini, M.; Maurenzig, P.; Olmi, A.; Taccetti, N.; Alard, J. P.; Amouroux, V.; Basrak, Z.; Bastid, N.; Belayev, I. M.; Berger, L.; Blaich, Th.; Boussange, S.; Buta, A.; Čaplar, R.; Cerruti, C.; Cindro, N.; Coffin, J. P.; Donà, R.; Dupieux, P.; Dželalija, M.; Erö, J.; Fan, Z. G.; Fintz, P.; Fodor, Z.; Fraysse, L.; Freifelder, R.; Frolov, S.; Gobbi, A.; Grigorian, Y.; Guillaume, G.; Herrmann, N.; Hildenbrand, K. D.; Hölbling, S.; Houari, A.; Jeong, S. C.; Jundt, F.; Kecskemeti, J.; Koncz, P.; Korchagin, Y.; Kotte, R.; Krämer, M.; Kuhn, C.; Ibnouzahir, M.; Legrand, I.; Lebedev, A.; Maguire, C.; Manko, V.; Mgebrishvili, G.; Mösner, J.; Moisa, D.; Montarou, G.; Montbel, I.; Morel, P.; Neubert, W.; Pelte, D.; Petrovici, M.; Rami, F.; Ramillien, V.; Reisdorf, W.; Sadchikov, A.; Schüll, D.; Seres, Z.; Sikora, B.; Simion, V.; Smolyankin, S.; Sodan, U.; The, K.; Tezkratt, R.; Trzaska, M.; Vasiliev, M. A.; Wagner, P.; Wessels, J. P.; Wienold, T.; Wilhelmi, Z.; Wohlfarth, D.; Zhilin, A. V.; Danielewicz, P.; FOPI Collaboration

1995-02-01

Light-particle emission from Au+Au collisions has been studied in the bombarding-energy range 100-250 A·MeV, using ΔE- ER telescopes in coincidence with the FOPI detector in its phase I configuration. Center-of-mass energy spectra have been measured for Z = 1,2 isotopes emitted in central collisions at CM polar angles between 60° and 90°. Evidence for a collective expansion is reported, on the basis of the mean kinetic energies of hydrogen isotopes. Comparison is presented with statistical calculations (WIX code). For CM kinetic energy spectra, fair agreement is found between data and a recently developed transport model.

Evidence for collective expansion in light-particle emission following Au+Au collisions at 100, 150 and 250 A.MeV

International Nuclear Information System (INIS)

Poggi, G.; Pasquali, G.; Bini, M.

1995-01-01

Light-particle emission from Au+Au collisions has been studied in the bombarding-energy range 100-250A.MeV, using ΔE-E R telescopes in coincidence with the FOPI detector in its phase I configuration. Center-of-mass energy spectra have been measured for Z=1, 2 isotopes emitted in central collisions at CM polar angles between 60 circle and 90 circle . Evidence for a collective expansion is reported, on the basis of the mean kinetic energies of hydrogen isotopes. Comparison is presented with statistical calculations (WIX code). For CM kinetic energy spectra, fair agreement is found between data and a recently developed transport model. ((orig.))

Calculations for very low energy scattering of positrons by molecular hydrogen

Energy Technology Data Exchange (ETDEWEB)

Cooper, J.N. [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)], E-mail: james.cooper@maths.nottingham.ac.uk; Armour, E.A.G. [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

2008-02-15

We give a progress report on ongoing calculations of phase shifts for very low energy elastic scattering of positrons by molecular hydrogen, using the generalised Kohn variational method. Further, provisional calculations of Z{sub eff} for molecular hydrogen at low energies are presented and discussed. The preliminary nature of the work is emphasised throughout.

Gas phase hydrogen peroxide production in atmospheric pressure glow discharges operating in He - H2O

NARCIS (Netherlands)

Vasko, C.A.; Veldhuizen, van E.M.; Bruggeman, P.J.

2013-01-01

The gas phase production of hydrogen peroxide (H2O2) in a RF atmospheric pressure glow discharge with helium and water vapour has been investigated as a function of the gas flow. It is shown that the production of H2O2 is through the recombination of two OH radicals in a three body collision and the

Recent developments in the theory of photon-photon collisions

International Nuclear Information System (INIS)

Brodsky, S.J.

1984-09-01

Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references

IEA Hydrogen Implementing Agreement's Second Generation R and D and the Hydrogen Economy

Energy Technology Data Exchange (ETDEWEB)

Beck, N.; Garcia-Conde, A. G.; Riis, T. U.; Luzzi, A.; Valladares, M. R. de

2005-07-01

Since its creation by the International Energy Agency in the late 1970's, the IEA Hydrogen Implementing Agreement (HIA) has been at the forefront of collaborative international hydrogen research and development (R and D) (http://www.ieahia.org. ) The collective body of HIA hydrogen R and D will contribute to definition of the hydrogen economy. The five-year [2004-2009) mission of the IEA HIA is to advance the adoption of a Hydrogen Economy through strategic implementation of collaborative R and D and outreach programs that address key issues and barriers. The three goals for the Second Generation HIA are: Advancement of science and technology via pre-commercial collaborative RD and D programs; Assessment of market environment, including the non-energy sector; and Implementation of outreach program, aimed at community acceptance and support. The HIA launched its Second Generation of hydrogen R and D in the latter part of 2004. The HIA's anniversary report: In Pursuit of the Future: 25 Years of IEA Research towards the realization of Hydrogen Energy Systems (http://ieahia.org/pdfs/IEA_AnniversaryReport_HIA.pdf) chronicles its contributions to hydrogen R and D. As the hydrogen economy takes shape, the HIA is pleased to share highlights of its R and D history together with progress on planned activities and its six current annexes, listed below: Task 15 Photobiological Production of Hydrogen Task 16 Hydrogen from Carbon-Containing Materials Task 17 Solid and Liquid Storage Task 18 Integrated Systems Evaluation Task 19 Safety Task 20 Hydrogen from Waterphotolysis Planned successor annexes in storage and photobiological hydrogen production will also be discussed, along with a task on high temperature hydrogen production that is now in the definition phase. Over 250 experts from the sixteen member HIA countries and the European Union contribute to this portfolio of cutting edge hydrogen R and D and analysis activities. Several other countries are expected to

Fragmentation of molecular ions in slow electron collisions

International Nuclear Information System (INIS)

Novotny, Steffen

2008-01-01

The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD + the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2 nd order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H 2 + produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

Fragmentation of molecular ions in slow electron collisions

Energy Technology Data Exchange (ETDEWEB)

Novotny, Steffen

2008-06-25

The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD{sup +} the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2{sup nd} order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H{sub 2}{sup +} produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

Progress of the ELISE test facility: towards one hour pulses in hydrogen

Science.gov (United States)

Wünderlich, D.; Fantz, U.; Heinemann, B.; Kraus, W.; Riedl, R.; Wimmer, C.; the NNBI Team

2016-10-01

In order to fulfil the ITER requirements, the negative hydrogen ion source used for NBI has to deliver a high source performance, i.e. a high extracted negative ion current and simultaneously a low co-extracted electron current over a pulse length up to 1 h. Negative ions will be generated by the surface process in a low-temperature low-pressure hydrogen or deuterium plasma. Therefore, a certain amount of caesium has to be deposited on the plasma grid in order to obtain a low surface work function and consequently a high negative ion production yield. This caesium is re-distributed by the influence of the plasma, resulting in temporal instabilities of the extracted negative ion current and the co-extracted electrons over long pulses. This paper describes experiments performed in hydrogen operation at the half-ITER-size NNBI test facility ELISE in order to develop a caesium conditioning technique for more stable long pulses at an ITER relevant filling pressure of 0.3 Pa. A significant improvement of the long pulse stability is achieved. Together with different plasma diagnostics it is demonstrated that this improvement is correlated to the interplay of very small variations of parameters like the electrostatic potential and the particle densities close to the extraction system.

Materials Down Select Decisions Made Within the Department of Energy Hydrogen Sorption Center of Excellence

Energy Technology Data Exchange (ETDEWEB)

Simpson, Lin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2009-11-30

Technical report describing DOE's Hydrogen Sorption Center of Excellence investigation into various adsorbent and chemisorption materials and progress towards meeting DOE's hydrogen storage targets. The report presents a review of the material status as related to DOE hydrogen storage targets and explains the basis for the down select decisions.

Destruction of fast H(2S) atoms in collisions with neon, krypton, xenon, and molecular hydrogen

International Nuclear Information System (INIS)

Roussel, F.; Pradel, P.; Spiess, G.

1977-01-01

Measurements are reported for the total quenching of metastable hydrogen atoms by neon, krypton, xenon, and molecular hydrogen, in the energy range 0.052--3 keV. The cross sections are found to be on the order of 5 x 10 -15 cm 2 at the lowest energies, and decrease to approximately 2 x 10 -15 cm 2 at the highest energies. The data at low energy are analyzed using a simple theoretical model

Hydrogen engine performance analysis project. Second annual report

Energy Technology Data Exchange (ETDEWEB)

Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

1980-01-01

Progress in a 3 year research program to evaluate the performance and emission characteristics of hydrogen-fueled internal combustion engines is reported. Fifteen hydrogen engine configurations will be subjected to performance and emissions characterization tests. During the first two years, baseline data for throttled and unthrottled, carburetted and timed hydrogen induction, Pre IVC hydrogen-fueled engine configurations, with and without exhaust gas recirculation (EGR) and water injection, were obtained. These data, along with descriptions of the test engine and its components, the test apparatus, experimental techniques, experiments performed and the results obtained, are given. Analyses of other hydrogen-engine project data are also presented and compared with the results of the present effort. The unthrottled engine vis-a-vis the throttled engine is found, in general, to exhibit higher brake thermal efficiency. The unthrottled engine also yields lower NO/sub x/ emissions, which were found to be a strong function of fuel-air equivalence ratio. (LCL)

International bulletin on atomic and molecular data for fusion. No. 18

International Nuclear Information System (INIS)

Katsonis, K.

1982-02-01

This bulletin deals with atomic and molecular data for fusion. A bibliography for the most recent data presented in the document is provided. Work in progress is briefly reported (electron impact excitation of hydrogen-like argon ions, excitation and charge transfer in collisions of Li atoms with alpha particles)

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

International Nuclear Information System (INIS)

Oya, Yasuhisa; Hatano, Yuji; Shimada, Masashi; Buchenauer, Dean; Kolasinski, Robert; Merrill, Brad; Kondo, Sosuke; Hinoki, Tatsuya; Alimov, Vladimir Kh.

2016-01-01

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

Energy Technology Data Exchange (ETDEWEB)

Oya, Yasuhisa, E-mail: syoya@ipc.shizuoka.ac.jp [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Hatano, Yuji [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan); Shimada, Masashi [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Livermore, CA 94551 (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kondo, Sosuke; Hinoki, Tatsuya [Kyoto University, Gokasho, Uji 611-0011 (Japan); Alimov, Vladimir Kh. [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan)

2016-12-15

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Collision Mechanics

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Servis, D.P.; Zhang, Shengming

1999-01-01

The first section of the present report describes the procedures that are being programmed at DTU for evaluation of the external collision dynamics. Then follows a detailed description of a comprehensive finite element analysis of one collision scenario for MS Dextra carried out at NTUA. The last...

Cluster-collision frequency. II. Estimation of the collision rate

International Nuclear Information System (INIS)

Amadon, A.S.; Marlow, W.H.

1991-01-01

Gas-phase cluster-collision rates, including effects of cluster morphology and long-range intermolecular forces, are calculated. Identical pairs of icosahedral or dodecahedral carbon tetrachloride clusters of 13, 33, and 55 molecules in two different relative orientations were discussed in the preceding paper [Phys. Rev. A 43, 5483 (1991)]: long-range interaction energies were derived based upon (i) exact calculations of the iterated, or many-body, induced-dipole interaction energies for the clusters in two fixed relative orientations; and (ii) bulk, or continuum descriptions (Lifshitz--van der Waals theory), of spheres of corresponding masses and diameters. In this paper, collision rates are calculated according to an exact description of the rates for small spheres interacting via realistic potentials. Utilizing the interaction energies of the preceding paper, several estimates of the collision rates are given by treating the discrete clusters in fixed relative orientations, by computing rotationally averaged potentials for the discrete clusters, and by approximating the clusters as continuum spheres. For the discrete, highly symmetric clusters treated here, the rates using the rotationally averaged potentials closely approximate the fixed-orientation rates and the values of the intercluster potentials for cluster surface separations under 2 A have negligible effect on the overall collision rates. While the 13-molecule cluster-collision rate differs by 50% from the rate calculated as if the cluster were bulk matter, the two larger cluster-collision rates differ by less than 15% from the macroscopic rates, thereby indicating the transition of microscopic to macroscopic behavior

Monte Carlo calculation of collisions of directionally-incident electrons on highly excited hydrogen atoms

International Nuclear Information System (INIS)

Kawakami, Kazuki; Fujimoto, Takasi

2001-01-01

We treat classically the n-, l- and m r -changing transitions and ionization. Excitation cross sections against the final state energy continue smoothly to the 'ionization cross sections'. The steady state populations determined by elastic collisions among the degenerate states in the same n level show higher populations in the m 1 =0 states, suggesting positive polarizations of Lyman lines emitted from plasmas having directional electrons. For ionization, the two outgoing electrons have large relative angles, suggesting reduced three body recombination rates for these plasmas. (author)

Theoretical studies in elementary particle physics: [Progress report for the period June 1986 to February 1987

International Nuclear Information System (INIS)

Collins, J.C.

1987-01-01

Theoretical research on elementary particles is reported, with progress discussed in these areas: heavy quark production, the cosmic rays observed from Cygnus X-3, hadron-hadron collisions at small values of x, Monte Carlo event generators for hadron-hadron collisions, review of perturbative QCD theorems, direct computation of helicity amplitudes for tree diagrams, and application of the factorization of helicity amplitudes to the effective W approximation

Quantum-mechanical study of ionization in slow collisions of antiprotons with hydrogen atoms

International Nuclear Information System (INIS)

Sakimoto, Kazuhiro

2004-01-01

The cross sections for the ionization p+H→p+p+e at low collision energies are computed with a complete quantum-mechanical method of time-dependent wave-packet propagation, which was applied to the protonium formation (→pp+e) by the present author [Phys. Rev. A 65, 012706 (2002)]. The ionization process shows very large cross sections even near threshold energy. An impact-parameter semiclassical method, in which the trajectory bending is taken into account by the introduction of the adiabatic potential, is also examined for the calculation of the ionization cross section. The semiclassical results are in good agreement with the quantum-mechanical results

Improved adiabatic calculation of muonic-hydrogen-atom cross sections. I. Isotopic exchange and elastic scattering in asymmetric collisions

International Nuclear Information System (INIS)

Cohen, J.S.; Struensee, M.C.

1991-01-01

The improved adiabatic representation is used in calculations of elastic and isotopic-exchange cross sections for asymmetric collisions of pμ, dμ, and tμ with bare p, d, and t nuclei and with H, D, and T atoms. This formulation dissociates properly, correcting a well-known deficiency of the standard adiabatic method for muonic-atom collisions, and includes some effects at zeroth order that are normally considered nonadiabatic. The electronic screening is calculated directly and precisely within the improved adiabatic description; it is found to be about 30% smaller in magnitude than the previously used value at large internuclear distances and to deviate considerably from the asymptotic form at small distances. The reactance matrices, needed for calculations of molecular-target effects, are given in tables

The LHC cryogenic operation for first collisions and physics run

CERN Document Server

Brodzinski, K; Benda, V; Bremer, J; Casas-Cubillos, J; Claudet, S; Delikaris, D; Ferlin, G; Fernandez Penacoba, G; Perin, A; Pirotte, O; Soubiran, M; Tavian, L; van Weelderen, R; Wagner, U

2011-01-01

The Large Hadron Collider (LHC) cryogenic system was progressively and successfully run for the LHC accelerator operation period starting from autumn 2009. The paper recalls the cryogenic system architecture and main operation principles. The system stability during magnets powering and availability periods for high energy beams with first collisions at 3.5 TeV are presented. Treatment of typical problems, weak points of the system and foreseen future consolidations will be discussed.

Theoretical atomic and molecular physics: Progress report, July 1, 1988 through June 30, 1989

International Nuclear Information System (INIS)

Lane, N.F.

1989-01-01

The theoretical atomic and molecular physics program at Rice University emphasizes fundamental questions regarding the structure and collision dynamics of various atomic and molecular systems with some attention given to atomic processes at surfaces. Our activities have been centered on continuing the projects initiated last year as well as beginning some new studies. These include: differential elastic and charge-transfer scattering and alignment and orientation of the excited electron cloud in ion-atom, atom-atom and ion-molecule collisions, using a molecular-orbital representation and both semiclassical and quantal methods; quenching of low-lying Rydberg states of a sodium atom in a collision with a rare-gas atom, using a semiclassical representation; so far, target atoms He, Ne and Ar have been studied; chemiionization and ion-pair formation in a collision of a Li atom with a metastable He atom at intermediate collision energies, using a combination of quantal and semi-classical methods; Penning ionization of alkali atoms Na and K, using advanced Cl and Stieltjes imaging methods; radiative and nonradiative charge-transfer in He + + H collisions at ultra-low collision energies, using quantal methods; elastic and inelastic processes in electron-molecule collisions, using the continuum-multiple-scattering method; and inelastic collision processes in dense, high-temperature plasmas. Selected highlights of our research progress are briefly summarized in this paper

ICP-MS with hexapole collision cell for isotope ratio measurements of Ca, Fe, and Se.

Science.gov (United States)

Boulyga, S F; Becker, J S

2001-07-01

To avoid mass interferences on analyte ions caused by argon ions and argon molecular ions via reactions with collision gases, an rf hexapole filled with helium and hydrogen has been used in inductively coupled plasma mass spectrometry (ICP-MS), and its performance has been studied. Up to tenfold improvement in sensitivity was observed for heavy elements (m > 100 u), because of better ion transmission through the hexapole ion guide. A reduction of argon ions Ar+ and the molecular ions of argon ArX+ (X = O, Ar) by up to three orders of magnitude was achieved in a hexapole collision cell of an ICP-MS ("Platform ICP", Micromass, Manchester, UK) as a result of gas-phase reactions with hydrogen when the hexapole bias (HB) was set to 0 V; at an HB of 1.6 V argon, and argon-based ions of masses 40 u, 56 u, and 80 u, were reduced by approximately four, two, and five orders of magnitude, respectively. The signal-to-noise ratio 80Se/ 40Ar2+ was improved by more than five orders of magnitude under optimized experimental conditions. Dependence of mass discrimination on collision-cell properties was studied in the mass range 10 u (boron) to 238 u (uranium). Isotopic analysis of the elements affected by mass-spectrometric interference, Ca, Fe, and Se, was performed using a Meinhard nebulizer and an ultrasonic nebulizer (USN). The measured isotope ratios were comparable with tabulated values from IUPAC. Precision of 0.26%, 0.19%, and 0.12%, respectively, and accuracy of 0.13% 0.25%, and 0.92%, respectively, was achieved for isotope ratios 44Ca/ 40Ca and 56Fe/57Fe in 10 microg L(-1) solution nebulized by means of a USN and for 78Se/80Se in 100 microg L(-1) solution nebulized by means of a Meinhard nebulizer.

Particle production in high energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Stock, R.

1985-05-01

Recent data on the production of pions and strange particles at the Bevalac and Synchrophasotron accelerators are reviewed, covering pion spectra and multiplicity distributions, Λ, K + and K - yields and spectra, and Λ polarization. Emphasis is placed on recent progress in determining the equation of state of compressed fireball nuclear matter from the observed pion yield in central collisions. Further, the information derived from apparent spectral temperatures is critically examined, along with a discussion of thermal and chemical equilibrium attainment in the reactions, as revealed by particle spectra and yields. (orig.)

Atom capture and loss in ion molecule collisions

International Nuclear Information System (INIS)

Breinig, M.; Lasley, S.E.; Gaither, C.C. III.

1985-01-01

Progress is reported in measuring the energy and angular distribution of protons emerging with velocity close to the beam velocity from the target region when Ar + beams collide with a CH 4 target and ArH + beams collide with a He target at asymptotically high speeds. The protons result from the transfer of a target constituent to the projectile (atom capture) or from the dissociation of the projectile molecule in the collision (atom loss). For atom capture processes the Thomas peak is clearly observed. 10 refs., 3 figs

Hydrogen fuelled buses: Italian ENEA research program

International Nuclear Information System (INIS)

Ambrosini, G.; Ciancia, A.; Pede, G.

1993-01-01

Current hydrogen automotive fuels research studies being conducted by ENEA (Italian Agency for New Technology, Energy and the Environment) are being targeted towards the development of hydrogen fueled vans and buses for use in highly polluted urban environments where the innovative vehicles' air pollution abatement characteristics would justify their high operating costs as compared with those of conventional automotive alternatives. The demonstration vehicle being used in the experimental studies and performance tests is a two liter minibus with a spark ignition engine power rated at 55 kW with gasoline operation and 45 kW with hydrogen. Detailed design notes are given regarding the retrofitting of the minibus chassis to house the aluminium gas storage tanks and the adaptation of the engine to operate with compressed hydrogen. Attention is given to efforts being made to resolve combustion control and fueling problems. Focus is on the progress being made in the development of an efficient and safe electronically controlled fuel injection system

Experimental studies of elementary particle interactions at high energies: Technical progress report

International Nuclear Information System (INIS)

1987-01-01

This paper discusses progress of experiments at CERN and Fermilab. At CERN, data accumulation and analysis is discussed for the UA-6 experiment, which involves proton-antiproton collisions. At Fermilab, the testing of a collider detector for the Tevatron is discussed

Shape of the Hα emission line in non resonant charge exchange in hydrogen plasmas

International Nuclear Information System (INIS)

Susino Bueno, A.; Zurro Hernandez, B.

1977-01-01

The Hα line shape emitted from a maxwellian hydrogen plasma and produced by non resonant change exchange has been calculated. Its explicit shape depends on the ion temperature, on background neutral energy and on the relative shape of the collision cross section. A comparison between theoretical and experimental shapes of the Hα line is carried out to check the model and to deduce the ion plasma temperature. (author) [es

Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

2015-12-31

The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

Summary of heavy ion theory

International Nuclear Information System (INIS)

Gavin, S.

1994-09-01

Can we study hot QCD using nuclear collisions? Can we learn about metallic hydrogen from the impact of comet Shoemaker-Levy 9 on Jupiter? The answer to both questions may surprise you exclamation point I summarize progress in relativistic heavy ion theory reported at DPF '94 in the parallel sessions

High-energy collisions of particles, strings, and branes

CERN Document Server

Veneziano, Gabriele

2015-01-01

This chapter summarizes some 25 years of work on the transplanckian-energy collisions of particles, strings, and branes, seen as a theoretical laboratory for understanding how gravity and quantum mechanics can be consistently combined in string theory. The ultimate aim of the exercise is to understand whether and how a consistent quantization of gravity can solve some longstanding paradoxes, such as the apparent loss of information in the production and decay of black holes at a semiclassical level. Considerable progress has been made in understanding the emergence of General Relativity expectations and in evaluating several kinds of quantum string corrections to them in the weak-gravity regime while keeping unitarity manifest. While some progress has also been made in the strong-gravity/gravitational collapse domain, full control of how unitarity works in that regime is still lacking.

Differential cross sections for transfer into the 2S state of hydrogen: H+ + H2, H+ + D2

International Nuclear Information System (INIS)

Williams, D.G.; Lee, A.R.; Butcher, E.C.

1986-01-01

Differential cross sections for electron capture into the 2S state of hydrogen are presented for the reactions H + + H 2 and H + + D 2 . The results are for laboratory collision energies between 3.3 and 24 keV and scattering angles between 30 and 90'. The measurements expand on the results previously presented. (author)

High energy experimental physics. Progress report and renewal proposal

International Nuclear Information System (INIS)

Rosen, J.; Miller, D.

1985-01-01

Technical progress is summarized for activities in these areas: study of charm particle production in hadronic collisions (data analysis); large-aperture multiparticle spectrometer; TEV I debuncher ring profile monitor; beta source monochromatizer; final reduction of data from pp and p anti p elastic scattering; high energy elastic scattering and cross section review; consequences of the Auberson-Kinoshita-Martin theorem for the nuclear slope parameter; planning and final design of the elastic scattering and total cross section experiment at the Tevatron Collider; a D-zero pp project and photoproduction experiment; lepton production in heavy-ion collisions; prompt gamma and massive lepton-pair production apparatus; and spin physics with the Fermilab polarized beam facility

Are high energy heavy ion collisions similar to a little bang, or just a very nice firework?

Energy Technology Data Exchange (ETDEWEB)

Shuryak, E.V. [State University of New York, NY (United States)

2001-07-01

The talk is a brief overview of recent progress in heavy ion physics, with emphasis on applications of macroscopic approaches. The central issues are whether the systems exhibit macroscopic behavior we need in order to interpret it as excited hadronic matter, and, if so, what is its effective Equation of State (EoS). This, in turn, depends on the collision rate in matter: we think we understand in hadronic matter near freeze-out, but certainly not at earlier stages of the collisions. Still (and this is about the most important statement we make) there is no indication that is not high enough, so that a hydro description of excited matter be possible. More specifically, we concentrate on such properties of the produced excited system as collective flow, particle composition and fluctuations relaxation are ultimately a measure of a collision rate we would like to know. We also try to explain what exactly are the expected differences between collisions at AGS/SPS and RHIC energies. (author)

Are high energy heavy ion collisions similar to a little bang, or just a very nice firework?

International Nuclear Information System (INIS)

Shuryak, E.V.

2001-01-01

The talk is a brief overview of recent progress in heavy ion physics, with emphasis on applications of macroscopic approaches. The central issues are whether the systems exhibit macroscopic behavior we need in order to interpret it as excited hadronic matter, and, if so, what is its effective Equation of State (EoS). This, in turn, depends on the collision rate in matter: we think we understand in hadronic matter near freeze-out, but certainly not at earlier stages of the collisions. Still (and this is about the most important statement we make) there is no indication that is not high enough, so that a hydro description of excited matter be possible. More specifically, we concentrate on such properties of the produced excited system as collective flow, particle composition and fluctuations relaxation are ultimately a measure of a collision rate we would like to know. We also try to explain what exactly are the expected differences between collisions at AGS/SPS and RHIC energies. (author)

Laser-assisted atom-atom collisions

International Nuclear Information System (INIS)

Roussel, F.

1984-01-01

The basic layer-assisted atom-atom collision processes are reviewed in order to get a simpler picture of the main physical facts. The processes can be separated into two groups: optical collisions where only one atom is changing state during the collision, the other acting as a spectator atom, and radiative collisions where the states of the two atoms are changing during the collision. All the processes can be interpreted in terms of photoexcitation of the quasimolecule formed during the collisional process. (author)

Binary-collision-approximation simulation for noble gas irradiation onto plasma facing materials

International Nuclear Information System (INIS)

Saito, Seiki; Nakamura, Hiroaki; Takayama, Arimichi; Ito, Atsushi M

2014-01-01

A number of experiments show that helium plasma constructs filament (fuzz) structures whose diameter is in nanometer-scale on the tungsten material under the suitable experimental condition. In this paper, binary-collision-approximation-based simulation is performed to reveal the mechanism and the conditions of fuzz formation of tungsten material under plasma irradiation. The irradiation of the plasma of hydrogen, deuterium, and tritium, and also the plasma of noble gas such as helium, neon, and argon atoms are investigated. The possibility of fuzz formation is discussed on the simulation result of penetration depth of the incident atoms

Electron removal from H and He atoms in collisions with C q+ , O q+ ions

Science.gov (United States)

Janev, R. K.; McDowell, M. R. C.

1984-06-01

Cross sections for electron capture and ionisation in collision of partially and completely stripped C q+ , N q+ and O q+ ions with hydrogen and helium atoms have been calculated at selected energies. The classical trajectory Monte Carlo method was used with a variable-charge pseudopotential to describe the interaction of the active electron with the projectile ion. A scalling relationship has been derived for the electron removal (capture and ionisation) cross section which allows a unifield representation of the data.

Atomic processes in hydrogen and deuterium negative ion discharges

International Nuclear Information System (INIS)

Hiskes, J.R.

1992-01-01

A knowledge of the atomic processes active in a hydrogen negative ion discharge and their respective rates is an essential component of the interpretation, modeling, and enhancement of negative ion systems. The generation of the cross sections and rate processes appropriate to this problem has been a principal activity at several laboratories. In this paper is discussed those collision processes that are of major importance for the destruction of the vibrationally excited molecules generated in the discharge, processes that are essential to the valuation of the optimization procedure that is to be discussed in this paper

Hard probes in heavy ion collisions at the LHC: PDFs, shadowing and $pA$ collisions

CERN Document Server

Accardi, Alberto; Botje, M.; Brodsky, S.J.; Cole, B.; Eskola, K.J.; Fai, George I.; Frankfurt, L.; Fries, R.J.; Geist, Walter M.; Guzey, V.; Honkanen, H.; Kolhinen, V.J.; Kovchegov, Yu.V.; McDermott, M.; Morsch, A.; Qiu, Jian-wei; Salgado, C.A.; Strikman, M.; Takai, H.; Tapprogge, S.; Vogt, R.; Zhang, X.f.

2003-01-01

This manuscript is the outcome of the subgroup ``PDFs, shadowing and $pA$ collisions'' from the CERN workshop ``Hard Probes in Heavy Ion Collisions at the LHC''. In addition to the experimental parameters for $pA$ collisions at the LHC, the issues discussed are factorization in nuclear collisions, nuclear parton distributions (nPDFs), hard probes as the benchmark tests of factorization in $pA$ collisions at the LHC, and semi-hard probes as observables with potentially large nuclear effects. Also, novel QCD phenomena in $pA$ collisions at the LHC are considered. The importance of the $pA$ program at the LHC is emphasized.

The Cost of Prior Restraint: "U. S. v. The Progressive."

Science.gov (United States)

Soloski, John; Dyer, Carolyn Stewart

Increased litigation and rising litigation costs threaten the future of newspapers and magazines. A case study was conducted to determine the costs and effects of "United States v. 'The Progressive,'" a prior restraint case over the publication in 1979 of an article on the hydrogen bomb. "The Progressive," which operates at a…

Theoretical maximal storage of hydrogen in zeolitic frameworks.

Science.gov (United States)

Vitillo, Jenny G; Ricchiardi, Gabriele; Spoto, Giuseppe; Zecchina, Adriano

2005-12-07

Physisorption and encapsulation of molecular hydrogen in tailored microporous materials are two of the options for hydrogen storage. Among these materials, zeolites have been widely investigated. In these materials, the attained storage capacities vary widely with structure and composition, leading to the expectation that materials with improved binding sites, together with lighter frameworks, may represent efficient storage materials. In this work, we address the problem of the determination of the maximum amount of molecular hydrogen which could, in principle, be stored in a given zeolitic framework, as limited by the size, structure and flexibility of its pore system. To this end, the progressive filling with H2 of 12 purely siliceous models of common zeolite frameworks has been simulated by means of classical molecular mechanics. By monitoring the variation of cell parameters upon progressive filling of the pores, conclusions are drawn regarding the maximum storage capacity of each framework and, more generally, on framework flexibility. The flexible non-pentasils RHO, FAU, KFI, LTA and CHA display the highest maximal capacities, ranging between 2.86-2.65 mass%, well below the targets set for automotive applications but still in an interesting range. The predicted maximal storage capacities correlate well with experimental results obtained at low temperature. The technique is easily extendable to any other microporous structure, and it can provide a method for the screening of hypothetical new materials for hydrogen storage applications.

Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen

Science.gov (United States)

Draganic, I. N.; Havener, C. C.; Schultz, D. R.; Seely, D. G.; Schultz, P. C.

2011-05-01

Total cross sections of charge exchange (CX) for C5+, N6+, and O7+ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1 - 20,000 eV/u. Absolute CX measurements are performed using an improved merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H+ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous H-oven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close-coupling (MOCC) and atomic orbital close-coupling (AOCC) theoretical calculations. Work supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, and the Office of Basic Energy Sciences of the U.S. DoE.

Investigation of the Direct Charge Transfer in Low Energy D2+ + H Collisions using Merged-Beams Technique

Science.gov (United States)

Romano, S. L.; Guillen, C. I.; Andrianarijaona, V. M.; Havener, C. C.

2011-10-01

The hydrogen - hydrogen (deuterium) molecular ion is the most fundamental ion-molecule two-electron system. Charge transfer (CT) for H2+ on H, which is one of the possible reaction paths for the (H-H2)+ system, is of special interest because of its contribution to H2 formation in the early universe, its exoergicity, and rich collision dynamics. Due to technical difficulty in making an atomic H target, the direct experimental investigations of CT for H2+ on H are sparse and generally limited to higher collision energies. The measurements of the absolute cross section of different CT paths for H2+ on H over a large range of collision energy are needed to benchmark theoretical calculations, especially the ones at low energies. The rate coefficient of CT at low energy is not known but may be comparable to other reaction rate coefficients in cold plasmas with H, H+, H2+, and H3+ as constituents. For instance, CT for H2+ on H and the following H3+ formation reaction H2+ + H2 → H + H3+ are clearly rate interdependent although it was always assumed that every ionization of H2 will lead to the formation of H3+. CT proceeds through dynamically coupled electronic, vibrational and rotational degrees of freedom. One can depict three paths, electronic CT, CT with nuclear substitution, and CT with dissociation. Electronic CT and CT with nuclear substitution in the H2+ on H collisions are not distinguishable by any quantum theory. Here we use the isotopic system (D2+ - H) to measure without ambiguity the electronic CT cross section by observing the H+ products. Using the ion-atom merged-beam apparatus at Oak Ridge National Laboratory, the absolute direct CT cross sections for D2+ + H from keV/u to meV/u collision energies have been measured. The molecular ions are extracted from an Electron-Cyclotron Resonance (ECR) ion source with a vibrational state distribution which is most likely determined by Frank-Condon transitions between ground state D2 and D2+. A ground-state H beam

Subfilter Scale Modelling for Large Eddy Simulation of Lean Hydrogen-Enriched Turbulent Premixed Combustion

NARCIS (Netherlands)

Hernandez Perez, F.E.

2011-01-01

Hydrogen (H2) enrichment of hydrocarbon fuels in lean premixed systems is desirable since it can lead to a progressive reduction in greenhouse-gas emissions, while paving the way towards pure hydrogen combustion. In recent decades, large-eddy simulation (LES) has emerged as a promising tool to

Investigation of Soft Photon Production in Hadronic Collisions Using the OMEGA Spectrometer

CERN Multimedia

2002-01-01

The Omega Spectrometer, with a hydrogen target and two electromagnetic calorimeters, is used to investigate the anomalous production of soft $\\gamma$s in hadronic collisions. The experiment is aimed at confirming an observation made in BEBC: the yield of soft $\\gamma$s (70\\% of the $\\gamma$s have c.m. energies in the range (20~$<$~E(@g)~$<$~60~MeV)) exceeds the QED prediction of hadronic bremsstrahlung by a factor of 3. This effect may be related to the anomalous production of low mass lepton pairs (virtual $\\gamma$s) observed in several hadronic experiments. \\\\ \\\\ An interaction trigger is used to collect events of @p@+p collisions (and pp tagged by Cedars in the beam) at 280~GeV/c. The charged tracks are recorded by the @W spectrometer, the @g's in the two calorimeters. The @g's arising from hadronic radiative decay (mostly @p|0's) are reconstructed, and subtracted event by event. The remaining @g spectrum is studied, in a region of phase space where the background (e.g. bachelor @g's from uncompletel...

Collision Repair Campaign

Science.gov (United States)

The Collision Repair Campaign targets meaningful risk reduction in the Collision Repair source category to reduce air toxic emissions in their communities. The Campaign also helps shops to work towards early compliance with the Auto Body Rule.

SELF-CONSISTENT LANGEVIN SIMULATION OF COULOMB COLLISIONS IN CHARGED-PARTICLE BEAMS

International Nuclear Information System (INIS)

QIANG, J.; RYNE, R.; HABIB, S.

2000-01-01

In many plasma physics and charged-particle beam dynamics problems, Coulomb collisions are modeled by a Fokker-Planck equation. In order to incorporate these collisions, we present a three-dimensional parallel Langevin simulation method using a Particle-In-Cell (PIC) approach implemented on high-performance parallel computers. We perform, for the first time, a fully self-consistent simulation, in which the FR-iction and diffusion coefficients are computed FR-om first principles. We employ a two-dimensional domain decomposition approach within a message passing programming paradigm along with dynamic load balancing. Object oriented programming is used to encapsulate details of the communication syntax as well as to enhance reusability and extensibility. Performance tests on the SGI Origin 2000 and the Cray T3E-900 have demonstrated good scalability. Work is in progress to apply our technique to intrabeam scattering in accelerators

Probing vacuum structure in nuclear collisions. Research report period: 1992--1995

International Nuclear Information System (INIS)

Rafelski, J.

1995-02-01

This is a report of the research activities in the field of Relativistic Nuclear Collisions/Theoretical Nuclear Physics of Johann Refelski at University of Arizona, supported by the Department of Energy, Nuclear Physics Division under grant No. DE-FG02-92ER40733. This report comprises: Section 1 surveys the general context of the work and presents summary of wider research objectives; Section 2 reviews the progress in the interpretation of experimental data, primarily related to diagnosis of high density nuclear matter with strange particle production, in heavy ion collisions at 10--200 GeV A; Section 3 presents the status of the studies of a relativistic quantum transport theory and the related vacuum structure and particle production processes; Section 4 presents a compilation of research projects completed under auspices of this program, with a short narrative description of publication contents

Collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. Project progress report, June 1, 1979-May 31, 1980

International Nuclear Information System (INIS)

Morgan, T.J.

1980-01-01

The objective of this program is to measure atomic collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. The goal is to obtain experimental information on atomic collision processes relevant to the Magnetic Fusion Energy Program. In particular, in connection with the development of double charge exchange D - ion sources, we are measuring D - formation cross sections in alkaline-earth metal vapor targets. During the period covered in this report we have measured electron transfer cross sections for 3-40 keV D + ions and D 0 atoms in collision with calcium vapor

Assessment of hydrogen risk using advanced methodology for lumped parameter code-MELCOR

International Nuclear Information System (INIS)

Duspiva, Jiri; Kujal, Bohumir

2007-01-01

The hydrogen risk is one of the most important containment integrity challenge during a severe accident progression at the VVER type reactors installed at the Czech NPPs. On the basis of recent comprehensive research results the general flame acceleration (FA) and deflagration-to-detonation transition (DDT) criteria were formulated. The main objective of the new methodology developed in the NRI Rez was to prepare an analytical tool for the assessment of the hydrogen risk at the Czech NPPs in the course of a severe accident and also for the design of hydrogen removal system which should be able to prevent or at least minimize the threats of hydrogen detonation in containments. The major idea on which the development of models for the FA and DDT criteria was based is described in OECD state-of-art report (NEA, 2000). The module for the computation of FA criterion (often named σ-criterion) and DDT one (also named λ or Dorofeev criterion) was linked to the MELCOR 1.8.5 model of VVER-1000 containment. The most important feature of new model is that it makes possible to evaluate the both of the criteria for all compartments in the containment continuously during severe accident scenario progression. The containment model, which could be used for such a calculation, has to be very detailed owing to appropriate description of hydrogen distribution. New model was tested by calculation of hydrogen detonation risk in the VVER-1000 containment during severe accident scenario initiated by medium break LOCA. At present two more VVER-1000 severe accident scenarios have been analyzed. The mapping of a hydrogen detonation risk in individual compartments inside containment was performed. The results of analysis confirm that the risk of hydrogen detonation in the great majority of containment compartments during severe accidents is very high if the hydrogen removal system is not installed. (author)

Fiscal 1976 Sunshine Project research report. Interim report (hydrogen energy); 1976 nendo chukan hokokushoshu. Suiso energy

Energy Technology Data Exchange (ETDEWEB)

NONE

1976-11-01

This report summarizes the Sunshine Project research interim reports on hydrogen energy of every organizations. The report includes research items, laboratories, institutes and enterprises concerned, research targets, research plans, and progress conditions. The research items are as follows. (1) Hydrogen production technology (electrolysis, high- temperature high-pressure water electrolysis, 4 kinds of thermochemical techniques, direct thermolysis). (2) Hydrogen transport and storage technology (2 kinds of solidification techniques). (3) Hydrogen use technology (combustion technology, fuel cell, solid electrolyte fuel cell, fuel cell power system, hydrogen fuel engine). (4) Hydrogen safety measures technology (disaster preventive technology for gaseous and liquid hydrogen, preventing materials from embrittlement due to hydrogen, hydrogen refining, transport and storage systems, their safety technology). (5) Hydrogen energy system (hydrogen energy system, hydrogen use subsystems, peripheral technologies). (NEDO)

Hydrogen system (hydrogen fuels feasibility)

International Nuclear Information System (INIS)

Guarna, S.

1991-07-01

This feasibility study on the production and use of hydrogen fuels for industry and domestic purposes includes the following aspects: physical and chemical properties of hydrogen; production methods steam reforming of natural gas, hydrolysis of water; liquid and gaseous hydrogen transportation and storage (hydrogen-hydride technology); environmental impacts, safety and economics of hydrogen fuel cells for power generation and hydrogen automotive fuels; relevant international research programs

Studies of hydrogen pellet acceleration with fuseless electromagnetic railgun

International Nuclear Information System (INIS)

Kim, K.

1986-01-01

A fuseless circular-bore electromagnetic railgun specifically designed for injection of high-velocity hydrogen pellets was constructed and tested. Hydrogen pellets were first accelerated to medium velocities (∼ 500 m/s) using a gas gun and then injected into the railgun. Once a pellet entered the railgun, a plasma arc was initiated by electrically breaking down the propellant gas which followed the pellet from the gas gun into the railgun. Utilizing the propulsive force of this plasma arc armature, further acceleration of the hydrogen pellet was achieved. Using a 60 cm long railgun, proof-of-principle experiments were performed on hydrogen pellets, 1.6 mm, in diameter and 2.15 mm in length, producing velocities exceeding 1.5 km/s. Encouraged by this preliminary success, more extensive studies are in progress to further improve the performance and capabilities of the current system

Probabilistic risk assessment on maritime spent nuclear fuel transportation (Part II: Ship collision probability)

International Nuclear Information System (INIS)

Christian, Robby; Kang, Hyun Gook

2017-01-01

This paper proposes a methodology to assess and reduce risks of maritime spent nuclear fuel transportation with a probabilistic approach. Event trees detailing the progression of collisions leading to transport casks’ damage were constructed. Parallel and crossing collision probabilities were formulated based on the Poisson distribution. Automatic Identification System (AIS) data were processed with the Hough Transform algorithm to estimate possible intersections between the shipment route and the marine traffic. Monte Carlo simulations were done to compute collision probabilities and impact energies at each intersection. Possible safety improvement measures through a proper selection of operational transport parameters were investigated. These parameters include shipment routes, ship's cruise velocity, number of transport casks carried in a shipment, the casks’ stowage configuration and loading order on board the ship. A shipment case study is presented. Waters with high collision probabilities were identified. Effective range of cruising velocity to reduce collision risks were discovered. The number of casks in a shipment and their stowage method which gave low cask damage frequencies were obtained. The proposed methodology was successful in quantifying ship collision and cask damage frequency. It was effective in assisting decision making processes to minimize risks in maritime spent nuclear fuel transportation. - Highlights: • Proposes a probabilistic framework on the safety of spent nuclear fuel transportation by sea. • Developed a marine traffic simulation model using Generalized Hough Transform (GHT) algorithm. • A transportation case study on South Korean waters is presented. • Single-vessel risk reduction method is outlined by optimizing transport parameters.

Hydrogen attack of steel. Progress report, April 1, 1978--March 31, 1979

International Nuclear Information System (INIS)

Shewmon, P.G.

1978-01-01

Four normalized carbon steels made in different ways (Si-killed, Al-killed, REM-treated, and electroslag refined) were studied to determine the role of differing fine inclusions on the early stages of hydrogen attack (HA). Hydrogen exposures were made at 450 0 C (6.5 MPa) and 375 0 C (7.6 MPa). The first stage of HA is shown to be the development of a closely spaced (1-2 μm) array of small bubbles over the ferrite/pearlite, or occasionally the ferrite/ferrite boundaries. These grew together to form tears, primarily in the rolling plane, leading to more rapid expansion normal to this plane. The planes of separation followed high solute layers in banded steel but only rarely did the fracture surfaces follow inclusions. At 450 0 C REM-treated steel was attacked the fastest and the Al-killed steel took two to four times as long for attack

Hydrogen movement and the next action: fossil fuels industry and sustainability economics

International Nuclear Information System (INIS)

Nejat Veziroglu, T.

1997-01-01

Since the hydrogen movement started in 1974, there has been progress in research, development, demonstration and commercialization activities, covering all aspects of the hydrogen energy system. In order to solve the interrelated problems of depletion of fossil fuels and the environmental impact of the combustion products of fossil fuels, it is desirable to speed up the conversion to the hydrogen energy system. Most established industries have joined the hydrogen movement. There is one exception: the fossil fuel industry. A call is made to the fossil fuel industry to join the hydrogen movement. It is also proposed to change the present economic system with a sustainability economics in order to account for environmental damage, recyclability and decommissioning, and thus, ensure a sustainable future. (Author)

Symbolic convergence and the hydrogen economy

International Nuclear Information System (INIS)

Sovacool, Benjamin K.; Brossmann, Brent

2010-01-01

This article documents that the hydrogen economy continues to attract significant attention among politicians, the media, and some academics. We believe that an explanation lies in the way that the hydrogen economy fulfills psychological and cultural needs related to a future world where energy is abundant, cheap, and pollution-free, a 'fantasy' that manifests itself with the idea that society can continue to operate without limits imposed by population growth and the destruction of the environment. The article begins by explaining its research methodology consisting of two literature reviews, research interviews of energy experts, and the application of symbolic convergence theory, a general communications theory about the construction of rhetorical fantasies. We then identify a host of socio-technical challenges to explain why the creation of a hydrogen economy would present immense (and possibly intractable) obstacles, an argument supplemented by our research interviews. Next, we employ symbolic convergence theory to identify five prevalent fantasy themes and rhetorical visions-independence, patriotism, progress, democratization, and inevitability-in academic and public discussions in favor of the hydrogen economy. We conclude by offering implications for scholarship relating to energy policy more broadly.

Plating end fittings to reduce hydrogen ingress at rolled joints in CANDU reactors

International Nuclear Information System (INIS)

White, A.J.; Urbanic, V.F.; Bahurmuz, A.A.; Clendening, W.R.; Joynes, R.; McDougall, G.M.; Skinner, B.C.; Venkatapathi, S.

1993-10-01

Zr-2.5Nb pressure tubes in CANDU nuclear reactors absorb hydrogen at a low rate from the primary heat transport water circulated through the tubes. Extra hydrogen is picked up at the rolled joints that connect the pressure tubes to out-of-core steel piping. This enhanced ingress may contribute to pressure-tube cracking at incorrectly assembled joints. The risk of pressure-tube failure has been decreased by ensuring correct joint assembly, and could be further decreased by reducing hydrogen ingress at rolled joints. This paper reviews progress toward using plated end fittings to reduce rolled-joint hydrogen ingress

Cross section measurements of the processes occurring in the fragmentation of H{sub n}{sup +} (3 {<=} n {<=} 35) hydrogen clusters induced by high speed (60 keV/u) collisions on helium atoms; Mesure des sections efficaces des differents processus intervenant dans la fragmentation d`agregats d`hydrogene H{sub n}{sup +} (3 {<=} n {<=} 35) induite par collision a haute vitesse (60 keV/u) sur un atome d`helium

Energy Technology Data Exchange (ETDEWEB)

Louc, Sandrine [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

1997-09-15

Different processes involved in the fragmentation of ionised hydrogen clusters H{sub 3} + (H{sub 2}){sub (n-3)/2} (n = 5-35) have been studied in the same experiment: the fragmentation of the cluster is induced by the collision with an helium atom at high velocity ({approx_equal} c/100). The collision is realised in reversed kinematic - clusters are accelerated - which allows the detection of neutral and charged fragments. The different channels of fragmentation are identified by using coincidence techniques. For all the cluster sizes studied the capture cross sections of one electron of the target by the cluster is equal to the capture cross section of the H{sub 3}{sup +} ion. In the same way, the dissociation cross section of the H{sub 3}{sup +} core of the cluster does not depend on cluster size. These fragmentation processes are due to the interaction of H{sub 3}{sup +} core of the cluster and the helium atom without ionization of another component of the cluster. On the contrary, the cross sections of loss of one, two and three molecules by the cluster and the dissociation cross section of the cluster in all its molecular components depends strongly on the cluster size. This dependence is different from the one measured for the metastable decay of the cluster. Thus, the process of loss of molecules induced by a collision should correspond to a different dissociation mechanism. In regard of the singularities observed for the size dependence, the H{sub 9}{sup +}, H{sub 15}{sup +}, H{sub 19}{sup +} and H{sub 29}{sup +} clusters could be the `core` of the biggest clusters. These observation are in agreement with the size effects of smaller magnitude observed for the dissociation cross section (all the processes). The values of the cross section for the process of at least one ionization of the cluster indicate that about 80% of the fragmentation events result from this process. (author) 114 refs., 74 figs., 9 tabs.

Hydrogen energy - the end of the beginning

International Nuclear Information System (INIS)

Stuart, A. K.

1997-01-01

Financial barriers to the widespread use of hydrogen energy were the principal messages contained in this banquet address. These barriers include the cost for the hydrogen, cost for the supply infrastructure and the cost of developing and building the special vehicles and appliances to use hydrogen. Some hopeful signs that hydrogen energy is emerging include Ballard's buses, early fuel cell private vehicle refueling station and remote energy systems which will be commercialized within the next ten years. The optimism is based on the effects of deregulation of the electric utility industry in the US now spreading to Canada and other countries, the appearance of effective direct hydrogen fuel cell vehicles under strong industrial sponsorship, and the near-term availability of electrolysis for hydrogen production at a fraction of present capital cost. Each of these reasons for optimism were elaborated in some detail. However, the main force behind the hydrogen solution for transportation is the environmental benefit, i.e. the potential of some one billion automobiles around the world running on an environmentally benign fuel, and the potential effect of that fact on global warming. The likely effects of continuing as before is no longer considered a viable option even by the greatest of skeptics of greenhouse gas emissions, a fact that will make the demand for 'clean' vehicles progressively more pressing with the passage of time. By increasing the hydrogen-to-carbon ratio in upgrading heavy hydrocarbons, the petroleum industry itself is showing the way to factor global warming issues into process choices. By going one step further and obtaining the hydrogen from non-fossil sources, the environmental benefits will be multiplied several fold

Cost reductions in nickel-hydrogen battery

Science.gov (United States)

Beauchamp, Richard L.; Sindorf, Jack F.

1987-01-01

Significant progress was made toward the development of a commercially marketable hydrogen nickel oxide battery. The costs projected for this battery are remarkably low when one considers where the learning curve is for commercialization of this system. Further developmental efforts on this project are warranted as the H2/NiO battery is already cost competitive with other battery systems.

Hydrogen attack of pressure-vessel steel. Progress report, April 1, 1980-March 31, 1981

International Nuclear Information System (INIS)

Shewmon, P.G.

1980-12-01

The nucleation and growth of methane bubbles in the hydrogen attack of pressure vessel steel has been shown to obey models developed to describe the growth of bubbles limiting the creep ductility of metals. This has been done through studies of the effect of prior deformation on bubble nucleation as well as the effect of methane pressure (stress) and temperature on growth kinetics. A comprehensive model of the factors limiting growth has been developed. Its application to the hydrogen attack of a 2 1/4 Cr-1 Mo steel leads to several interesting predictions

Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis.

Science.gov (United States)

Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Tafreshian, Amirmahdi; Valentine, Stephen J

2015-07-01

The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H](4+) ions exhibit two major conformer types with collision cross sections of 418 Å(2) and 446 Å(2); the [M + 3H](3+) ions also yield two different conformer types having collision cross sections of 340 Å(2) and 367 Å(2). Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H](3+) ions show faster HDX rate contributions compared with [M + 4H](4+) ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H](4+) ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).

Quark and Gluon Degrees of Freedom in High-Energy Heavy Ion Collisions

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J. [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: rjfries@comp.tamu.edu

2008-06-01

I discuss some recent progress in our understanding of high energy nuclear collisions. I will focus on two topics which I was lucky to co-pioneer in the recent past. One is recombination of quarks and its interpretation as a signal for deconfinement, the second is electromagnetic radiation from jets passing through a quark gluon plasma. This talk was given during the award ceremony for the 2007 IUPAP Young Scientist Award.

Collisional excitation of ArH+ by hydrogen atoms

Science.gov (United States)

Dagdigian, Paul J.

2018-06-01

The rotational excitation of the 36ArH+ ion in collisions with hydrogen atoms is investigated in this work. The potential energy surface (PES) describing the 36ArH+-H interaction, with the ion bond length r fixed at the average of r over the radial v = 0 vibrational state distribution, was obtained with a coupled cluster method that included single, double, and (perturbatively) triple excitations [RCCSD(T)]. A deep minimum (De = 3135 cm-1) in the PES was found in linear H-ArH+ geometry at an ion-atom separation Re = 4.80a0. Energy-dependent cross-sections and rate coefficients as a function of temperature for this collision pair were computed in close-coupling (CC) calculations. Since the PES possesses a deep well, this is a good system to test the performance of the quantum statistical (QS) method developed by Manolopoulos and co-workers as a more efficient method to compute the cross-sections. Good agreement was found between rate coefficients obtained by the CC and QS methods at several temperatures. In a simple application, the excitation of ArH+ is simulated for conditions under which this ion is observed in absorption.

Review of Solid State Hydrogen Storage Methods Adopting Different Kinds of Novel Materials

Directory of Open Access Journals (Sweden)

Renju Zacharia

2015-01-01

Full Text Available Overview of advances in the technology of solid state hydrogen storage methods applying different kinds of novel materials is provided. Metallic and intermetallic hydrides, complex chemical hydride, nanostructured carbon materials, metal-doped carbon nanotubes, metal-organic frameworks (MOFs, metal-doped metal organic frameworks, covalent organic frameworks (COFs, and clathrates solid state hydrogen storage techniques are discussed. The studies on their hydrogen storage properties are in progress towards positive direction. Nevertheless, it is believed that these novel materials will offer far-reaching solutions to the onboard hydrogen storage problems in near future. The review begins with the deficiencies of current energy economy and discusses the various aspects of implementation of hydrogen energy based economy.

Proposal for a Northeast Asian Hydrogen Highway: From a Natural-gas-based to a Hydrogen-based Society

International Nuclear Information System (INIS)

Kazuhiko O Hashi; Masaru Hirata; William C Leighty; D Eng

2006-01-01

In Northeast Asia, East Siberia and Sakhalin are rich in natural gas (NG). The environmental protection and energy security of the Northeast Asian region requires constructing an energy infrastructure network that can transport and distribute NG throughout the region in the near term, and renewable-source gaseous hydrogen (GH2) in the long term. We have promoted the construction of an NG pipeline network, the principal component of the energy infrastructure essential to our evolution toward a hydrogen-based society, through the Northeast Asia Natural Gas and Pipeline Forum (NAGPF). Our ultimate goal is a clean and sustainable society based on renewable energy sources, wherein hydrogen is produced from the vast potential of renewable energy in Siberia and China. The hydrogen thus produced would be transmitted through the pipeline network, progressively replacing NG as it is depleted. Over three-quarters of commercially exploitable hydroelectric power (hydro) resources of all Russia is in East Siberia. The areas from Kamchatka through the Kurilskiye Islands (called the Chishima Islands, in Japan) to Sakhalin is a world-class wind energy resource. West China has huge potential for solar energy. (authors)

Collisions of low-energy antiprotons and protons with atoms and molecules

International Nuclear Information System (INIS)

Luehr, Armin

2010-01-01

as well as from anti p and p impact are compared with each other and assessed. Furthermore, results obtained with oneelectron model potentials are compared to the full two-electron description of H 2 . Finally, stopping powers for anti p impacts are determined. A case study for H, H 2 , and He is performed which distinguishes for the first time systematically between the stopping powers of atomic and molecular hydrogen. In this work special emphasis is put on the detailed investigation of anti p+H 2 collisions. This includes the dependence of the cross sections on the internuclear distance and on the molecular orientation relative to the projectile trajectory. (orig.)

Hydrogen production by high-temperature gas-cooled reactor. Conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system

International Nuclear Information System (INIS)

Sakaba, Nariaki; Ohashi, Hirofumi; Sato, Hiroyuki; Hara, Teruo; Kato, Ryoma; Kunitomi, Kazuhiko

2008-01-01

Nuclear hydrogen production is necessary in an anticipated hydrogen society that demands a massive quantity of hydrogen without economic disadvantage. Japan Atomic Energy Agency (JAEA) has launched the conceptual design study of a hydrogen production system with a near-term plan to connect it to Japan's first high-temperature gas-cooled reactor HTTR. The candidate hydrogen production system is based on the thermochemical water-splitting iodine sulphur (IS) process.The heat of 10 MWth at approximately 900degC, which can be provided by the secondary helium from the intermediate heat exchanger of the HTTR, is the energy input to the hydrogen production system. In this paper, we describe the recent progresses made in the conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system. A new concept of sulphuric acid decomposer is proposed. This involves the integration of three separate functions of sulphuric acid decomposer, sulphur trioxide decomposer, and process heat exchanger. A new mixer-settler type of Bunsen reactor is also designed. This integrates three separate functions of Bunsen reactor, phase separator, and pump. The new concepts are expected to result in improved economics through construction and operation cost reductions because the number of process equipment and complicated connections between the equipment has been substantially reduced. (author)

Collisions of low-energy antiprotons and protons with atoms and molecules

Energy Technology Data Exchange (ETDEWEB)

Luehr, Armin

2010-02-18

comparison of the present findings for p impacts and for anti p+He collisions with literature data. On the other hand, total and differential cross sections for ionization and excitation of the targets by anti p impact complement the sparse literature data of this kind. Results gained from different targets as well as from anti p and p impact are compared with each other and assessed. Furthermore, results obtained with oneelectron model potentials are compared to the full two-electron description of H{sub 2}. Finally, stopping powers for anti p impacts are determined. A case study for H, H{sub 2}, and He is performed which distinguishes for the first time systematically between the stopping powers of atomic and molecular hydrogen. In this work special emphasis is put on the detailed investigation of anti p+H{sub 2} collisions. This includes the dependence of the cross sections on the internuclear distance and on the molecular orientation relative to the projectile trajectory. (orig.)

Solar photochemical production of HBr for off-peak electrolytic hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Heaton, H. [Solar Reactor Technologies Inc., Miami, FL (United States)

1996-10-01

Progress is reported on the development of a unique and innovative hydrogen production concept utilizing renewable (Solar) energy and incorporating energy storage. The concept is based on a solar-electrolytic system for production of hydrogen and oxygen. It employs water, bromine, solar energy, and supplemental electrical power. The process consumes only water, sunlight and off-peak electricity, and produces only hydrogen, oxygen, and peaking electrical power. No pollutants are emitted, and fossil fuels are not consumed. The concept is being developed by Solar Reactor Technologies, Inc., (SRT) under the auspices of a Cooperative Agreement with the U.S. Department of Energy (DOE).

Multi-wavelength study of two possible cloud-cloud collision regions: IRAS 02459+6029 and IRAS 22528+5936

International Nuclear Information System (INIS)

Li Nan; Wang Junjie

2012-01-01

Based on observations of 12 CO (J=2–1), we select targets from archived Infrared Astronomical Satellite (IRAS) data of IRAS 02459+6029 and IRAS 22528+5936 as samples of cloud-cloud collision, according to the criteria given by Vallee. Then we use the Midcourse Space Experiment (MSX) A band (8.28 μm) images and the NRAO VLA Sky Survey (NVSS) (1.4 GHz) continuum images to investigate the association between molecular clouds traced by the CO contour maps. The distribution of dust and ionized hydrogen shows an obvious association with the CO contour maps toward IRAS 02459+6029. However, in the possible collision region of IRAS 22528+5936, NVSS continuum radiation is not detected and the MSX sources are merely associated with the central star. The velocity fields of the two regions indicate the direction of the pressure and interaction. In addition, we have identified candidates of young stellar objects (YSOs) by using data from the Two Micron All Sky Survey (2MASS) in JHK bands expressed in a color-color diagram. The distribution of YSOs shows that the possible collision region is denser than other regions. All the evidence suggests that IRAS 02459+6029 could be an example of cloud-cloud collision, and that IRAS 22528+5936 could be two separate non-colliding clouds. (research papers)

Progress report, August 1, 1980-May 31, 1982

Energy Technology Data Exchange (ETDEWEB)

Rawitscher, G.H.

1982-02-10

Progress is briefly described on the following topics: (1) effect of deuteron breakup on elastic deuteron scattering cross sections and polarizations; (2) the validity of the discretization method; (3) the effect of breakup on rearrangement reactions; (4) formulation in terms of hyperspherical harmonics of the effect of breakup in deuteron-nucleous collisions; and (5) formulation of scattering theory in terms of a basis of positive energy Weinberg functions. (WHK)

Two-state approximation applied to hydrogen formation by proton impact on positronium

Directory of Open Access Journals (Sweden)

E Ghanbari Adivi

2009-09-01

Full Text Available Although there is no experimental data available for antihydrogen formation following antiprotons impact on positroium atoms, as a charge transfer reaction, at incident energies which are suitable for antimatter high-precision spectroscopic studies, measurements were carried out for its charge-conjugate reaction i. e. hydrogen formation, by protons impact on positronium. In this study, a two-state approximation method is applied to charge exchange process in proton-positronium collision system. The nonorthogonality of initial and final states and its effects on the angular distribution of the differential cross sections is taken into account by using this method. The state-to-state differential cross sections are reported for transition from ground state of positronium into the ground and a few lowest excited states of the formed hydrogen. Integrated cross sections are presented as well.

8. annual U.S. hydrogen meeting: Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-01-01

The proceedings contain 35 papers arranged under the following topical sections: Government`s partnership role for hydrogen technology development; Government/industry partnerships -- Demonstrations; Entering the market -- Partnerships in transportation; Hydrogen -- The aerospace fuel; Codes and Standards; Advanced technologies; and Opportunities for partnerships in the utility market. Of the three markets identified (transportation, power production, and village power) papers are presented dealing with the first two. Three parts of the transportation market were covered: cars, trucks, and buses. Progress was reported in both fuel cell and internal combustion engine vehicle propulsion systems. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

U.S. experience with hydrogen water chemistry in boiling water reactors

International Nuclear Information System (INIS)

Cowan, R.L.; Head, R.A.; Indig, M.E.; Ruiz, C.P.; Simpson, J.L.

1988-01-01

Hydrogen water chemistry in boiling water reactors is currently being adopted by many utilities in the U.S., with eleven units having completed preimplementation test programs, four units operating permanently with hydrogen water chemistry, and six other units in the process of installing permanent equipment. Intergranular stress corrosion cracking protection is required for the recirculation piping system and other regions of the BWR systems. The present paper explores progress in predicting and monitoring hydrogen water chemistry response in these areas. Testing has shown that impurities can play an important role in hydrogen water chemistry. Evaluation of their effects are also performed. Both computer modeling and in plant measurements show that each plant will respond uniquely to feedwater hydrogen addition. Thus, each plant has its own unique hydrogen requirement for recirculation system protecion. Furthermore, the modeling, and plant measurements show that different regions of the BWR respond differently to hydrogen injection. Thus, to insure protection of components other than the recirculation systems may require more (or less) hydrogen demand than indicated by the recirculation system measurements. In addition, impurities such as copper can play a significant role in establishing hydrogen demand. (Nogami, K.)

On impact mechanics in ship collisions

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Zhang, Shengming

1998-01-01

The purpose of this paper is to present analytical, closed-form expressions for the energy released for crushing and the impact impulse during ship collisions. Ship–ship collisions, ship collisions with rigid walls and ship collisions with flexible offshore structures are considered. The derived ...

On Impact Mechanics in Ship Collisions

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Zhang, Shengming

1998-01-01

The purpose of this paper is to present analytical, closed-form expressions for the energy released for crushing and the impact impulse during ship collisions. Ship-ship collisions, ship collisions with rigid walls and ship collisions with flexible offshore structures are considered. The derived ...

Electron-hydrogen collisions with dressed target and Volkov projectile states in a laser field

International Nuclear Information System (INIS)

Smith, P.H.G.; Flannery, M.R.

1992-01-01

Cross sections for the 1S-2S and 1S-2P O transitions in laser-assisted e - -H(1S) collisions are calculated in both the multi-channel eikonal treatment and the Born wave approximation, as a function of impact energy and laser field intensity. The laser considered is a monotonic, plane-polarized CO 2 laser (photon energy = 0.117 eV) with the polarization direction parallel to the initial projectile velocity. The first part of this paper confines the laser perturbation to the bound electrons of the atom. The second part extends the laser perturbation to the projectile electron, and the familiar Volkov dressed states are used. (author)

Gravitational waves from cosmic bubble collisions

International Nuclear Information System (INIS)

Kim, Dong-Hoon; Lee, Bum-Hoon; Lee, Wonwoo; Yang, Jongmann; Yeom, Dong-han

2015-01-01

Cosmic bubbles are nucleated through the quantum tunneling process. After nucleation they would expand and undergo collisions with each other. In this paper, we focus in particular on collisions of two equal-sized bubbles and compute gravitational waves emitted from the collisions. First, we study the mechanism of the collisions by means of a real scalar field and its quartic potential. Then, using this model, we compute gravitational waves from the collisions in a straightforward manner. In the quadrupole approximation, time-domain gravitational waveforms are directly obtained by integrating the energy-momentum tensors over the volume of the wave sources, where the energy-momentum tensors are expressed in terms of the scalar field, the local geometry and the potential. We present gravitational waveforms emitted during (i) the initial-to-intermediate stage of strong collisions and (ii) the final stage of weak collisions: the former is obtained numerically, in full General Relativity and the latter analytically, in the flat spacetime approximation. We gain qualitative insights into the time-domain gravitational waveforms from bubble collisions: during (i), the waveforms show the non-linearity of the collisions, characterized by a modulating frequency and cusp-like bumps, whereas during (ii), the waveforms exhibit the linearity of the collisions, featured by smooth monochromatic oscillations. (orig.)

Laser-driven polarized hydrogen and deuterium internal targets

International Nuclear Information System (INIS)

Jones, C.E.; Fedchak, J.A.; Kowalczyk, R.S.

1995-01-01

After completing comprehensive tests of the performance of the source with both hydrogen and deuterium gas, we began tests of a realistic polarized deuterium internal target. These tests involve characterizing the atomic polarization and dissociation fraction of atoms in a storage cell as a function of flow and magnetic field, and making direct measurements of the average nuclear tensor polarization of deuterium atoms in the storage cell. Transfer of polarization from the atomic electron to the nucleus as a result of D-D spin-exchange collisions was observed in deuterium, verifying calculations suggesting that high vector polarization in both hydrogen and deuterium can be obtained in a gas in spin temperature equilibrium without inducing RF transitions between the magnetic substates. In order to improve the durability of the system, the source glassware was redesigned to simplify construction and installation and eliminate stress points that led to frequent breakage. Improvements made to the nuclear polarimeter, which used the low energy 3 H(d,n) 4 He reaction to analyze the tensor polarization of the deuterium, included installing acceleration lenses constructed of wire mesh to improve pumping conductance, construction of a new holding field coil, and elimination of the Wien filter from the setup. These changes substantially simplified operation of the polarimeter and should have reduced depolarization in collisions with the wall. However, when a number of tests failed to show an improvement of the nuclear polarization, it was discovered that extended operation of the system with a section of teflon as a getter for potassium caused the dissociation fraction to decline with time under realistic operating conditions, suggesting that teflon may not be a suitable material to eliminate potassium from the target. We are replacing the teflon surfaces with drifilm-coated ones and plan to continue tests of the polarized internal target in this configuration

Experimental medium energy physics: Annual progress report June 1987--May 1988

International Nuclear Information System (INIS)

1988-01-01

This report discusses progress in experimental medium energy physics at Carnegie Mellon University. Some of the topics covered are: search for the ξ(2230); hyperon-antihyperon production studies; relativistic proton-nucleus and heavy ion-nucleus collisions; H dibaryon physics; hypernuclear physics research; pion physics; H particle experiment design and development; and electron scattering

Generation IV nuclear energy systems and hydrogen economy. New progress in the energy field in the 21st century

International Nuclear Information System (INIS)

Zang Mingchang

2004-01-01

The concept of hydrogen economy was initiated by the United States and other developed countries in the turn of the century to mitigate anxiety of national security due to growing dependence on foreign sources of energy and impacts on air quality and the potential effects of greenhouse gas emissions. Hydrogen economy integrates the primary energy used to produce hydrogen as a future energy carrier, hydrogen technologies including production, delivery and storage, and various fuel cells for transportation and stationary applications. A new hydrogen-based energy system would created as an important solution in the 21st century, flexible, affordable, safe, domestically produced, used in all sectors of the economy and in all regions of the country, if all the R and D plans and the demonstration come to be successful in 20-30 years. Among options of primary energy. Generation IV nuclear energy under development is particularly well suited to hydrogen production, offering the competitive position of large-scale hydrogen production with near-zero emissions. (author)

On the quantum Landau collision operator and electron collisions in dense plasmas

Energy Technology Data Exchange (ETDEWEB)

Daligault, Jérôme, E-mail: daligaul@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-03-15

The quantum Landau collision operator, which extends the widely used Landau/Fokker-Planck collision operator to include quantum statistical effects, is discussed. The quantum extension can serve as a reference model for including electron collisions in non-equilibrium dense plasmas, in which the quantum nature of electrons cannot be neglected. In this paper, the properties of the Landau collision operator that have been useful in traditional plasma kinetic theory and plasma transport theory are extended to the quantum case. We outline basic properties in connection with the conservation laws, the H-theorem, and the global and local equilibrium distributions. We discuss the Fokker-Planck form of the operator in terms of three potentials that extend the usual two Rosenbluth potentials. We establish practical closed-form expressions for these potentials under local thermal equilibrium conditions in terms of Fermi-Dirac and Bose-Einstein integrals. We study the properties of linearized quantum Landau operator, and extend two popular approximations used in plasma physics to include collisions in kinetic simulations. We apply the quantum Landau operator to the classic test-particle problem to illustrate the physical effects embodied in the quantum extension. We present useful closed-form expressions for the electron-ion momentum and energy transfer rates. Throughout the paper, similarities and differences between the quantum and classical Landau collision operators are emphasized.

On the quantum Landau collision operator and electron collisions in dense plasmas

Science.gov (United States)

Daligault, Jérôme

2016-03-01

The quantum Landau collision operator, which extends the widely used Landau/Fokker-Planck collision operator to include quantum statistical effects, is discussed. The quantum extension can serve as a reference model for including electron collisions in non-equilibrium dense plasmas, in which the quantum nature of electrons cannot be neglected. In this paper, the properties of the Landau collision operator that have been useful in traditional plasma kinetic theory and plasma transport theory are extended to the quantum case. We outline basic properties in connection with the conservation laws, the H-theorem, and the global and local equilibrium distributions. We discuss the Fokker-Planck form of the operator in terms of three potentials that extend the usual two Rosenbluth potentials. We establish practical closed-form expressions for these potentials under local thermal equilibrium conditions in terms of Fermi-Dirac and Bose-Einstein integrals. We study the properties of linearized quantum Landau operator, and extend two popular approximations used in plasma physics to include collisions in kinetic simulations. We apply the quantum Landau operator to the classic test-particle problem to illustrate the physical effects embodied in the quantum extension. We present useful closed-form expressions for the electron-ion momentum and energy transfer rates. Throughout the paper, similarities and differences between the quantum and classical Landau collision operators are emphasized.

The 1989 progress report: theoretical Physics

International Nuclear Information System (INIS)

Laval, G.

1989-01-01

The 1989 progress report of the laboratory of theoretical Physics of the Polytechnic School (France) is presented. The investigations reported concern the following subjects: the transport of a passive vector by a flow, the conformal field theories, the dynamics of wetting, the electromagnetic properties of composite materials, the neutrino oscillations, the heavy ion collision phenomenology, the laser-plasma interaction, the construction of a code for simulating the evolution of magnetohydrodynamic instabilities in plasmas. The published papers, the conferences and the Laboratory staff are listed [fr

Combustion characteristics of natural gas-hydrogen hybrid fuel turbulent diffusion flame

Energy Technology Data Exchange (ETDEWEB)

El-Ghafour, S.A.A.; El-dein, A.H.E.; Aref, A.A.R. [Mechanical Power Engineering Department, Faculty of Engineering, Suez Canal University, Port-Said (Egypt)

2010-03-15

Combustion characteristics of natural gas - hydrogen hybrid fuel were investigated experimentally in a free jet turbulent diffusion flame flowing into a slow co-flowing air stream. Experiments were carried out at a constant jet exit Reynolds number of 4000 and with a wide range of NG-H{sub 2} mixture concentrations, varied from 100%NG to 50%NG-50% H{sub 2} by volume. The effect of hydrogen addition on flame stability, flame length, flame structure, exhaust species concentration and pollutant emissions was conducted. Results showed that, hydrogen addition sustains a progressive improvement in flame stability and reduction in flame length, especially for relatively high hydrogen concentrations. Hydrogen-enriched flames found to have a higher combustion temperatures and reactivity than natural gas flame. Also, it was found that hydrogen addition to natural gas is an ineffective strategy for NO and CO reduction in the studied range, while a significant reduction in the %CO{sub 2} molar concentration by about 30% was achieved. (author)

K$^0_S$ and $\\Lambda$ production in Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

CERN Document Server

Abelev, Betty Bezverkhny; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agocs, Andras Gabor; Agostinelli, Andrea; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahmed, Ijaz; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arbor, Nicolas; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bairathi, Vipul; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, Fernando; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Bogolyubskiy, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Bornschein, Joerg; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile Ioan; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Sukalyan; Chattopadhyay, Subhasis; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contin, Giacomo; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dainese, Andrea; Dang, Ruina; Danu, Andrea; Das, Kushal; Das, Debasish; Das, Indranil; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; Delagrange, Hugues; Deloff, Andrzej; Denes, Ervin Sandor; Deppman, Airton; Oliveira Valeriano De Barros, Gabriel; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; De Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Dietel, Thomas; Divia, Roberto; Di Bari, Domenico; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Doenigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutt Mazumder, Abhee Kanti; D'Erasmo, Ginevra; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erazmus, Barbara Ewa; Erdal, Hege Austrheim; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigory; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floratos, Emmanouil; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gorlich, Lidia Maria; Gomez Jimenez, Ramon; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gotovac, Sven; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Costin; Grigoras, Alina Gabriela; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Khan, Kamal; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard Richard; Hippolyte, Boris; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Gian Michele; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacholkowski, Adam Wlodzimierz; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalcher, Sebastian; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Ketzer, Bernhard Franz; Khan, Shuaib Ahmad; Khan, Mohammed Mohisin; Khan, Palash; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Minwoo; Kim, Mimae; Kim, Taesoo; Kim, Jinsook; Kim, Do Won; Kim, Dong Jo; Kim, Beomkyu; Kim, Se Yong; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratyev, Valery; Kondratyeva, Natalia; Konevskikh, Artem; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasilij; Kweon, Min Jung; Kwon, Youngil; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; La Pointe, Sarah Louise; La Rocca, Paola; Lea, Ramona; Lechman, Mateusz Arkadiusz; Lee, Sung Chul; Lee, Graham Richard; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenhardt, Matthieu Laurent; Lenti, Vito; Leoncino, Marco; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Lohner, Daniel; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luzzi, Cinzia; Jacobs, Peter Martin; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martin Blanco, Javier; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mazer, Joel Anthony; Mazumder, Rakesh; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Nyanin, Alexander; Nyatha, Anitha; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Sun Kun; Oh, Saehanseul; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Pachmayer, Yvonne Chiara; Pachr, Milos; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares Vales, Carlos; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woojin; Passfeld, Annika; Patalakha, Dmitry; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piyarathna, Danthasinghe; Planinic, Mirko; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Pop, Amalia; Porteboeuf, Sarah Julie; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Sudhir; Raniwala, Rashmi; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Rauch, Wolfgang Hans; Rauf, Aamer Wali; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rivetti, Angelo; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Sharma, Rohni; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Pradip Kumar; Roy, Christelle Sophie; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Santoro, Romualdo; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Scott, Patrick Aaron; Segato, Gianfranco; Selyuzhenkov, Ilya; Seo, Jeewon; Serci, Sergio; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Satish; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Soltz, Ron Ariel; Song, Myunggeun; Song, Jihye; Soos, Csaba; Soramel, Francesca; Spacek, Michal; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Ter-Minasyan, Astkhik; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Torii, Hisayuki; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urciuoli, Guido Maria; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vande Vyvre, Pierre; Vannucci, Luigi; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Diozcora Vargas Trevino, Aurora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Sergey; Voloshin, Kirill; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wagner, Jan; Wang, Yifei; Wang, Yaping; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Kengo; Weber, Michael; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Xiang, Changzhou; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yang, Shiming; Yano, Satoshi; Yasnopolskiy, Stanislav; Yi, Jungyu; Yin, Zhongbao; Yoo, In-Kwon; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Fan; Zhang, Yonghong; Zhang, Haitao; Zhang, Xiaoming; Zhou, Daicui; Zhou, You; Zhou, Fengchu; Zhu, Xiangrong; Zhu, Jianlin; Zhu, Jianhui; Zhu, Hongsheng; Zichichi, Antonino; Zimmermann, Markus Bernhard; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

2013-11-25

The ALICE measurement of K$^0_S$ and $\\Lambda$ production at mid-rapidity in Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV is presented. The transverse momentum ($p_T$) spectra are shown for several collision centrality intervals and in the $p_T$ range from 0.4 GeV/c (0.6 GeV/c for $\\Lambda$) to 12 GeV/c. The $p_T$ dependence of the $\\Lambda/K^0_S$ ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher $p_T$ with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at $\\sqrt{s}$ = 0.9 TeV and at $\\sqrt{s}$ = 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured $p_T$ spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of $p_T$, models that incorporate the influence of...

Tetrahydroborates: Development and Potential as Hydrogen Storage Medium

Directory of Open Access Journals (Sweden)

Julián Puszkiel

2017-10-01

Full Text Available The use of fossil fuels as an energy supply becomes increasingly problematic from the point of view of both environmental emissions and energy sustainability. As an alternative, hydrogen is widely regarded as a key element for a potential energy solution. However, different from fossil fuels such as oil, gas, and coal, the production of hydrogen requires energy. Alternative and intermittent renewable sources such as solar power, wind power, etc., present multiple advantages for the production of hydrogen. On one hand, the renewable sources contribute to a remarkable reduction of pollutants released to the air. On the other hand, they significantly enhance the sustainability of energy supply. In addition, the storage of energy in form of hydrogen has a huge potential to balance an effective and synergetic utilization of the renewable energy sources. In this regard, hydrogen storage technology presents a key roadblock towards the practical application of hydrogen as “energy carrier”. Among the methods available to store hydrogen, solid-state storage is the most attractive alternative both from the safety and the volumetric energy density points of view. Because of their appealing hydrogen content, complex hydrides and complex hydride-based systems have attracted considerable attention as potential energy vectors for mobile and stationary applications. In this review, the progresses made over the last century on the development in the synthesis and research on the decomposition reactions of homoleptic tetrahydroborates is summarized. Furthermore, theoretical and experimental investigations on the thermodynamic and kinetic tuning of tetrahydroborates for hydrogen storage purposes are herein reviewed.

Recognizing Single Collisions of PtCl6(2-) at Femtomolar Concentrations on Ultramicroelectrodes by Nucleating Electrocatalytic Clusters.

Science.gov (United States)

Dick, Jeffrey E; Bard, Allen J

2015-11-04

We report the electrodeposition of electrocatalytic clusters of platinum from femtomolar platinate solutions. An inert carbon fiber ultramicroelectrode (UME) was held at a potential where proton reduction was unfavorable on carbon but favorable on platinum in a 1 M sulfuric acid solution. Upon addition of femtomolar amounts of hexachloroplatinic acid, which will also reduce to Pt(0) at the applied potential on the carbon fiber UME, cathodic blips were observed in the amperometric i-t response. These blips correspond to the reduction of protons to molecular hydrogen at the small platinum clusters followed by a rapid deactivation likely due to hydrogen bubble formation. On average, these current spikes occur when five platinum atoms have been formed on the electrode, as determined by a comparative analysis of experimental cathodic blips and calculated hexachloroplatinate molecule collision frequencies.

Are High Energy Heavy Ion Collisions similar to a Little Bang, or just a very nice Firework?

Science.gov (United States)

Shuryak, E. V.

2001-09-01

The talk is a brief overview of recent progress in heavy ion physics, with emphasis on applications of macroscopic approaches. The central issues are whether the systems exhibit macroscopic behavior we need in order to interpret it as excited hadronic matter, and, if so, what is its effective Equation of State (EoS). This, in turn, depends on the collision rate in matter: we think we understand in hadronic matter near freeze-out, but certainly not at earlier stages of the collisions. Still (and this is about the most important statement we make) there is no indication that it is not high enough, so that a hydro description of excited matter be possible. More specifically, we concentrate on such properties of the produced excited system as collective flow, particle composition and fluctuations. Note that both a generation of a pressure and the rate of fluctuation relaxation are ultimately a measure of a collision rate we would like to know. We also try to explain what exactly are the expected differences between collisions at AGS/SPS and RHIC energies.

Trending in Probability of Collision Measurements

Science.gov (United States)

Vallejo, J. J.; Hejduk, M. D.; Stamey, J. D.

2015-01-01

A simple model is proposed to predict the behavior of Probabilities of Collision (P(sub c)) for conjunction events. The model attempts to predict the location and magnitude of the peak P(sub c) value for an event by assuming the progression of P(sub c) values can be modeled to first order by a downward-opening parabola. To incorporate prior information from a large database of past conjunctions, the Bayes paradigm is utilized; and the operating characteristics of the model are established through a large simulation study. Though the model is simple, it performs well in predicting the temporal location of the peak (P(sub c)) and thus shows promise as a decision aid in operational conjunction assessment risk analysis.

Fuzzy Reasoning as a Base for Collision Avoidance Decision Support System

Directory of Open Access Journals (Sweden)

tanja brcko

2013-12-01

Full Text Available Despite the generally high qualifications of seafarers, many maritime accidents are caused by human error; such accidents include capsizing, collision, and fire, and often result in pollution. Enough concern has been generated that researchers around the world have developed the study of the human factor into an independent scientific discipline. A great deal of progress has been made, particularly in the area of artificial intelligence. But since total autonomy is not yet expedient, the decision support systems based on soft computing are proposed to support human navigators and VTS operators in times of crisis as well as during the execution of everyday tasks as a means of reducing risk levels.This paper considers a decision support system based on fuzzy logic integrated into an existing bridge collision avoidance system. The main goal is to determine the appropriate course of avoidance, using fuzzy reasoning.

Strangeness in nuclear collisions

International Nuclear Information System (INIS)

Gazdzicki, M.; Roehrich, D.

1996-01-01

Data on the mean multiplicity of strange hadrons produced in minimum bias proton-proton and central nucleus-nucleus collisions at momenta between 2.8 and 400 GeV/c per nucleon have been compiled. The multiplicities for nucleon-nucleon interactions were constructed. The ratios of strange particle multiplicity to participant nucleon as well as to pion multiplicity are larger for central nucleus-nucleus collisions than for nucleon-nucleon interactions at all studied energies. The data at AGS energies suggest that the latter ratio saturates with increasing masses of the colliding nuclei. The strangeness to pion multiplicity ratio observed in nucleon-nucleon interactions increases with collision energy in the whole energy range studied. A qualitatively different behaviour is observed for central nucleus-nucleus collisions: the ratio rapidly increases when going from Dubna to AGS energies and changes little between AGS and SPS energies. This change in the behaviour can be related to the increase in the entropy production observed in central nucleus-nucleus collisions at the same energy range. The results are interpreted within a statistical approach. They are consistent with the hypothesis that the quark gluon plasma is created at SPS energies, the critical collision energy being between AGS and SPS energies. (orig.)

Collision-produced atomic states

International Nuclear Information System (INIS)

Andersen, N.; Copenhagen Univ.

1988-01-01

The last 10-15 years have witnessed the development of a new, powerful class of experimental techniques for atomic collision studies, allowing partial or complete determination of the state of the atoms after a collision event, i.e. the full set of quantum-mechanical scattering amplitudes or - more generally - the density matrix describing the system. Evidently, such studies, involving determination of alignment and orientation parameters, provide much more severe tests of state-of-the-art scattering theories than do total or differential cross section measurements which depend on diagonal elements of the density matrix. The off-diagonal elements give us detailed information about the shape and dynamics of the atomic states. Therefore, close studies of collision-produced atomic states are currently leading to deeper insights into the fundamental physical mechanisms governing the dynamics of atomic collision events. The first part of the lectures deals with the language used to describe atomic states, while the second part presents a selection of recent results for model systems which display fundamental aspects of the collision physics in particularly instructive ways. I shall here restrict myself to atom-atom collisions. The discussion will be focused on states decaying by photon emission though most of the ideas can be easily modified to include electron emission as well. (orig./AH)

Cross-sections of charge and electronic states change of particles at ion-ion and ion-molecule collisions

International Nuclear Information System (INIS)

Panov, M.N.; Afrosimov, V.V.; Basalaev, A.A.; Guschina, N.A.; Nikulin, V.K.

2006-01-01

The interactions of protons and alpha-particles with hydrocarbons are investigated. A quantum-mechanical computation of the electronic structure of all hydrocarbons from methane to butane and its fragment ions was performed in the Hartree-Fock RHF/UHF approximation using a GAMESS program (General Atomic Molecular Electron Structure System). The correlation energy was taken into account within the framework of MP2 perturbation theory. The structural parameters of the hydrocarbon molecules and their charged and neutral fragments were calculated in two cases: in the geometry of the parent molecule or of the relaxation states. The difference of the full energy of the same fragments in and out of brackets gives us the vibration excitation energies of the fragments at the moment of creation. Additional Mulliken effective charges (in electron charge units) of atoms in the fragments have been calculated. The calculations show that removing one electron from the ethane molecule without electronic excitation produced a single charged molecular ion in vibration state with binding energy of hydrogen atoms, some decimal eV. As results we obtain C 2 H 6 + and C 2 H 5 + . Additional fragmentation of hydrocarbon needs electronic excitation of produced single charged ions. Cross sections for electron capture and excitation processes in collisions between the hydrogen-like He + , B 4+ and O 7+ ions have been evaluated. The purpose of the theory within this project during the period under review was to get for the first time new data on Single-Electron Capture (SEC) and Excitation Processes (EP) in collisions of He + (1s) ions with hydrogen-like impurity ions B 4+ (1s) and O 7+ (1s) in the energy range for He + ions from 0.2 MeV to 3.0 MeV. The calculations were carried out by using the method of close-coupling equations with basis sets of eleven and ten quasimolecular two-electron states for reactions (1, 2) and (3, 4), respectively (entrance channel, seven charge transfer channels

Section of Atomic Collisions

International Nuclear Information System (INIS)

Berenyi, D.; Biri, S.; Gulyas, L.; Juhasz, Z.; Kover, A.; Orban, A.; Palinkas, J.; Papp, T.; Racz, R.; Ricz, S.

2009-01-01

The Section of Atomic Collisions is a research unit with extended activity in the field of atomic and molecular physics. Starting from the study of atomic processes at the beamlines of nuclear physics accelerators in the seventies, our research community became one of the centers of fundamental research in Atomki. We also have a strong connection to materials sciences especially along the line of electron and ion spectroscopy methods. Our present activity covers a wide range of topics from atomic collision mechanisms of fundamental interest, to the complex interactions of electrons, ions, photons and antiparticles with atoms, molecules, surfaces, and specific nanostructures. In the last few years, an increasing fraction of our present topics has become relevant for applications, e.g., molecular collision studies for the radiation therapy methods of tumors, or ion-nanostructure interactions for the future construction of small ion-focusing elements. Our section belongs to the Division of Atomic Physics. The other unit of the Division is the Section of Electron Spectroscopy and Materials Sciences. There are traditionally good connections and a strong collaboration between the groups of the two sections in many fields. From the very beginning of our research work in atomic collisions, external collaborations were of vital importance for us. We regularly organize international workshops in the field of fast ion-atom collisions and related small conferences in Debrecen from 1981. Recently, we organized the Conference on Radiation Damage in Biomolecular Systems (RADAM 2008, Debrecen), and coorganized the Conference on Elementary Processes in Atomic Systems (CEPAS 2008, Cluj). We have access to several large scale facilities in Europe within the framework of formal and informal collaborations. The next themes are in this article: Forward electron emission from energetic atomic collisions; Positron-atom collisions; Photon-atom interactions; Interference effects in electron

Experimental and theoretical study of very-low-energy inelastic processes in electron-molecule collisions. Progress report, March 20, 1982-March 20, 1983

International Nuclear Information System (INIS)

Golden, D.E.; Morrison, M.

1983-01-01

Objectives of this research are: to determine accurate integrated and differential cross sections for low energy electron-molecule elastic scattering, excitation and ionization; to develop, implement, and test new experimental and theoretical procedures for studying low energy collision processes; and to contribute to basic understanding of a fundamental problem in atomic collision physics, the interaction of a charged particle with a non-spherical target that is rich in structure

Overview of Cea studies on hydrogen production and related prospects for nuclear power

International Nuclear Information System (INIS)

Agator, J.M.; Guigon, A.

2001-01-01

The anticipated growth of the world energy demand and the increasing concern about the emission of greenhouse gases, with the objectives of limitation fixed by the Kyoto protocol, provide the impetus for the development of hydrogenous fuels, and especially that of hydrogen as energy carrier. The trend will be reinforced in the longer term with the progressive shortage of natural hydrocarbon fuels. Fuel cells used in stationary, transport and portable applications will probably be the most efficient hydrogen converter and the most promising decentralized energy technology of the coming decades. In order to contribute to the reduction of greenhouse gas emissions, the massive use of hydrogen for transport and stationary applications calls for the development of production processes compatible with low CO 2 emissions, thus limiting the use of fossil fuels (natural gas, oil, coal, etc.) as reagent or energy sources. Furthermore, the progressive exhaustion of economic fossil fuel reserves will ultimately make it necessary to extract hydrogen from water through CO 2 -free processes. With this prospect in view, base-load nuclear energy, besides renewable energies, can play an important role to produce hydrogen through electrolysis in the medium term, as can high temperature thermo-chemical water dissociation processes in the longer term. Starting from current research in the field of fuel cells and hydrogen storage systems, the CEA intends to implement a large R and D programme on hydrogen, continuing previous research and covering the aspects of production, transport and related safety requirements. This endeavour is intended to reinforce the contribution of the CEA to the national and European research effort on non-fossil energy sources, and to create new opportunities of international collaboration and networking. (authors)

Overview of CEA studies on hydrogen production and related prospects for nuclear power

International Nuclear Information System (INIS)

Agator, J.M.; Guigon, A.; Serre-Combe, P.

2001-01-01

The anticipated growth of the world energy demand and the increasing concern about the emission of greenhouse gases, with the objectives of limitation fixed by the Kyoto protocol, prepare the ground for the development of hydrogenous fuels, and especially that of hydrogen as energy carrier. The trend will be reinforced in the longer term with the progressive shortage of natural hydrocarbon fuels. Fuel cells used in stationary, transport and portable applications will probably be the most efficient hydrogen converter and the most promising decentralized energy technology of the next decades. In order to contribute to the reduction of greenhouse gas emissions, a massive use of hydrogen for transport and stationary applications calls for the development of production processes compatible with low CO 2 emissions, thus limiting the use of fossil fuels (natural gas, oil, coal...) as reagent or energy sources. Furthermore, the progressive exhaustion of economic fossil fuel reserves will ultimately make it necessary to extract hydrogen from water through CO 2 free processes. With this prospect in view, base-load nuclear energy, besides renewable energies, can play an important role to produce hydrogen through electrolysis in the medium term, and also through high temperature thermochemical water dissociation processes in the longer term. Starting from current research in the field of fuel cans and hydrogen storage systems, the CEA intends to implement a large R and D programme on hydrogen also covering the aspects of production, transport and related safety requirements. This endeavour is intended to reinforce the contribution of the CEA to the national and European research effort on non-fossil energy sources, and to open new opportunities of international collaborations and networking. (authors)

Progress towards 3D black hole merger simulations

International Nuclear Information System (INIS)

Seidel, E.

2001-01-01

I review recent progress in 3D numerical relativity, focused on simulations involving black holes evolved with singularity avoiding slicings, but also touching on recent results in advanced techniques like black hole excision. After a long series of axisymmetric and perturbative studies of distorted black holes and black hole collisions, similar studies were carried out with full 3D codes. The results showed that such black hole simulations can be carried out extremely accurately, although instabilities plague the simulation at uncomfortably early times. However, new formulations of Einstein's equations allow much more stable 3D evolutions than ever before, enabling the first studies of 3D gravitational collapse to a black hole. With these new formulations, for example, it has been possible to perform the first detailed simulations of 3D grazing collisions of black holes with unequal mass, spin, and with orbital angular momentum. I discuss the 3D black hole physics that can now be studied, and prospects for the future, which look increasingly bright due to recent progress in formulations, black hole excision, new gauge conditions, and larger computers. Simulations may soon be able to provide information about the final plunge of two black holes, of relevance for gravitational wave astronomy. (author)

Ion induced fragmentation of biomolecular systems at low collision energies

International Nuclear Information System (INIS)

Bernigaud, V; Adoui, L; Chesnel, J Y; Rangama, J; Huber, B A; Manil, B; Alvarado, F; Bari, S; Hoekstra, R; Postma, J; Schlathoelter, T

2009-01-01

In this paper, we present results of different collision experiments between multiply charged ions at low collision energies (in the keV-region) and biomolecular systems. This kind of interaction allows to remove electrons form the biomolecule without transferring a large amount of vibrational excitation energy. Nevertheless, following the ionization of the target, fragmentation of biomolecular species may occur. It is the main objective of this work to study the physical processes involved in the dissociation of highly electronically excited systems. In order to elucidate the intrinsic properties of certain biomolecules (porphyrins and amino acids) we have performed experiments in the gas phase with isolated systems. The obtained results demonstrate the high stability of porphyrins after electron removal. Furthermore, a dependence of the fragmentation pattern produced by multiply charged ions on the isomeric structure of the alanine molecule has been shown. By considering the presence of other surrounding biomolecules (clusters of nucleobases), a strong influence of the environment of the biomolecule on the fragmentation channels and their modification, has been clearly proven. This result is explained, in the thymine and uracil case, by the formation of hydrogen bonds between O and H atoms, which is known to favor planar cluster geometries.

Chapter 6 Quantum Mechanical Methods for Loss-Excitation and Loss-Ionization in Fast Ion-Atom Collisions

Science.gov (United States)

Belkic, Dzevad

Inelastic collisions between bare nuclei and hydrogen-like atomic systems are characterized by three main channels: electron capture, excitation, and ionization. Capture dominates at lower energies, whereas excitation and ionization prevail at higher impact energies. At intermediate energies and in the region of resonant scattering near the Massey peak, all three channels become competitive. For dressed or clothed nuclei possessing electrons, such as hydrogen-like ions, several additional channels open up, including electron loss (projectile ionization or stripping). The most important aspect of electron loss is the competition between one- and two-electron processes. Here, in a typical one-electron process, the projectile emits an electron, whereas the target final and initial states are the same. A prototype of double-electron transitions in loss processes is projectile ionization accompanied with an alteration of the target state. In such a two-electron process, the target could be excited or ionized. The relative importance of these loss channels with single- and double-electron transitions involving collisions of dressed projectiles with atomic systems is also strongly dependent on the value of the impact energy. Moreover, impact energies determine which theoretical method is likely to be more appropriate to use for predictions of cross sections. At low energies, an expansion of total scattering wave functions in terms of molecular orbitals is adequate. This is because the projectile spends considerable time in the vicinity of the target, and as a result, a compound system comprised of the projectile and the target can be formed in a metastable molecular state which is prone to decay. At high energies, a perturbation series expansion is more appropriate in terms of powers of interaction potentials. In the intermediate energy region, atomic orbitals are often used with success while expanding the total scattering wave functions. The present work is focused on

Continuous dark fermentative hydrogen production by mesophilic microflora: Principles and progress

Energy Technology Data Exchange (ETDEWEB)

Hawkes, Freda R.; Hussy, Ines; Kyazze, Godfrey; Dinsdale, Richard; Hawkes, Dennis L. [School of Applied Sciences, University of Glamorgan, Pontypridd RCT CF37 1DL (United Kingdom)

2007-02-15

Continuous, dark fermentative hydrogen production technology using mixed microflora at mesophilic temperatures may be suitable for commercial development. Clostridial-based cultures from natural sources have been widely used, but more information on the need for heat treatment of inocula and conditions leading to germination and sporulation are required. The amount of nutrients given in the literature vary widely. Hydrogen production is reported to proceed without methane production in the reactor in the pH range 4.5-6.7, with hydraulic retention times optimally between a few hours and 3 days depending on substrate. Higher substrate concentrations should be more energy-efficient but there are product inhibition limitations, for example from unionised butyric acid. Inhibition by H{sub 2} can be reduced by stirring, sparging or extraction through membranes. Of the reactor types investigated, while granules have the best performance with soluble substrate, for particulate feedstock biofilm reactors or continuous stirred tank reactors may be most successful. A second stage is required to utilise the fermentation end products which, when cost-effective reactors are developed, may be photofermentation or microbial fuel cell technologies. Anaerobic digestion is a currently-available technology and the two-stage process is reported to give greater conversion efficiency than anaerobic digestion alone. (author)

International bulletin on atomic and molecular data for fusion. No. 25

International Nuclear Information System (INIS)

Katsonis, K.

1984-06-01

This bulletin deals with atomic and molecular data for fusion. A bibliography for the most recent data presented in the document is provided. Work in progress is also briefly reported (Collision strengths and recombination coefficients for ions of C,N,O; Reactions between ions and atomic hydrogen; Cross sections for electron impact ionisation of Ne + , Ti + and Ni + ions)

Charge changing and excitation cross sections for 1-25 KeV hydrogen ions and atoms incident on sodium

International Nuclear Information System (INIS)

Howald, A.M.

1983-01-01

Measurements of charge changing and excitation cross sections for 1-25 keV beams of hydrogen atoms and ions incident on a sodium vapor target are reported. The charge changing cross sections are for reactions in which the incident H ion or atom gains or loses an electron during a collision with a Na atoms to form a hydrogen ion or atom in a different charge state. The six cross sections measured are sigma/sub +0/ and sigma/sub +-/ for incident protons, sigma/sub -0/ and sigma/sub -+/ for incident H - ions, and sigma/sub g-/ and sigma/sub g+/ for incident H(1s) atoms. Measurements are also reported for the negative, neutral, and positve equilibrium fractions for H beams in thick Na targets. The excitation cross sections are for reactions in which the Na target atom is excited to the 3p level by a collision with a H atom or ion. The five cross sections measured are for incident H + , H 2 + , H 3 + , and H - ions, and for H(1s) atoms. These cross sections are measured using a new technique that compares them directly to the known cross section for excitation by electron impact

Collision-induced destructive quantum interference

International Nuclear Information System (INIS)

Yang Xihua; Sun Zhenrong; Zhang Shi'an; Ding Liang'en; Wang Zugeng

2005-01-01

We conduct theoretical studies on the collision-induced destructive quantum interference of two-colour two-photon transitions in an open rhomb-type five-level system with a widely separated doublet by the density matrix approach. The effects of the collision-induced decay rates, the ratio of the transition dipole moments and the energy separation of the doublet on the interference are analysed. It is shown that a narrow dip appears in the excitation spectrum due to the collision-induced destructive interference, and that the narrow interference dip still exists even when the collision broadening is comparable to the energy separation of the doublet. The physical origin of the collision-induced destructive quantum interference is analysed in the dressed-atom picture

Prediction of hydrogen distribution in the reactor building in CANDU6 plant

International Nuclear Information System (INIS)

Jin, Y.; Song, Y.

2008-01-01

The CANDU plants have a lot of zircaloy. The fuel cladding, calandria tubes and pressure tubes are made of zircaloy. The zircaloy can be oxidized and hydrogen is generated during severe accident progression. The detonation or deflagration to detonation transition (DDT) due to hydrogen combustion may occur if the local hydrogen concentration or global hydrogen concentration exceeds certain value. The detonation may result in the rupture of the reactor building. The inside of the reactor building of CANDU plants is complex. So prediction of hydrogen distribution in the reactor building is important. This prediction is made using ISAAC code and GOTHIC code. ISAAC code partitioned the reactor building in to 7 compartments. GOTHIC code modeled the CANDU6 reactor building using 12 nodes. The hydrogen concentrations in the various compartments in the reactor building are compared. GOTHIC code slightly underpredicts hydrogen concentration in the F/M rooms than ISAAC code, but trend is same. The hydrogen concentration in the boiler room and the moderator room shows almost same as for both codes. (author)

A Collective Collision Operator for DSMC

International Nuclear Information System (INIS)

Gallis, Michail A.; Torczynski, John R.

2000-01-01

A new scheme to simulate elastic collisions in particle simulation codes is presented. The new scheme aims at simulating the collisions in the highly collisional regime, in which particle simulation techniques typically become computationally expensive.The new scheme is based on the concept of a grid-based collision field. According to this scheme, the particles perform a single collision with the background grid during a time step. The properties of the background field are calculated from the moments of the distribution function accumulated on the grid. The collision operator is based on the Langevin equation. Based on comparisons with other methods, it is found that the Langevin method overestimates the collision frequency for dilute gases

Fusion related atomic physics. Progress report, June 1, 1975--February 28, 1976

International Nuclear Information System (INIS)

1976-02-01

Summaries of research progress on ion--atom collisions are given. Electron capture by high velocity point charges (bare nuclei with Z less than or equal to 9) was studied in several ways. Studies on the nuclear reactions induced by 13 C and 9 Be ions near the Coulomb barrier have continued

Black Holes at the LHC: Progress since 2002

International Nuclear Information System (INIS)

Park, Seong Chan

2008-01-01

We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the 'energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.

Electrical conductivity of highly ionized dense hydrogen plasma. II. Comparison of experiment and theory

Energy Technology Data Exchange (ETDEWEB)

Guenther, K [Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Elektronenphysik; Popovic, M M; Popovic, S S; Radtke, R

1976-05-11

The electrical conductivity of a non-ideal hydrogen plasma at p = 10 atm and T = 14,000-21,500 K is derived from electrical measurements and the radial temperature distribution of a pulsed wall-stabilized hydrogen arc using the theoretical temperature dependence of conductivity in an ideal binary collision plasma. From the comparison of theory and experiment, a suggestion to modify the cut-off parameter for charged particle potential from rsub(D) is derived, where rsub(D) is the Debye length. An estimate of Kaklyugin and Norman (Kaklyugin, A.S. and Norman, G.E., 1973 Teplofiz. vysok. temp., vol.11, 238-244) which takes into account both particle correlation and electron localisation in the environment of ions agrees very well with the experimental results over the whole temperature range.

The hydrogen; L'hydrogene

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

Neuromorphic UAS Collision Avoidance

Data.gov (United States)

National Aeronautics and Space Administration — Collision avoidance for unmanned aerial systems (UAS) traveling at high relative speeds is a challenging task. It requires both the detection of a possible collision...

Production of hyperthermal hydrogen atoms by an arc discharge

International Nuclear Information System (INIS)

Samano, E.C.

1993-01-01

A magnetically confined thermal electric arc gas heater has been designed and built as a suitable source of heat for dissociating hydrogen molecules with energy in the range of a few eV. Specifically, the average beam kinetic energy is determined to be 1.5 eV, the dissociation rate is 0.5 atoms per molecule and the atom beam intensity in the forward direction is 1018 atoms/sr-sec. The working pressure in the arc discharge region is from 15 to 25 torr. This novel atom source has been successfully ignited and operated with pure hydrogen during several hours of continuous performance, maintaining its characteristics. The hyperthermal hydrogen atom beam, which is obtained from this source is analyzed and characterized in a high vacuum system, the characterization of the atom beam is accomplished by two different methods: calorimetry and surface ionization. Calorimetic sensor were used for detecting the atom beam by measuring the delivered power of the impinging atoms on the sensor surface. In the second approach an H-surface production backscattering experiment from a low work function surface was conducted. The validity of these two methods is discussed, and the results are compared. The different collision mechanisms to dissociate and ionize hydrogen molecules in the arch discharge are reviewed, as well as the physics of electric arcs. Finally, a Monte Carlo simulation program is used to calculate the ionization probability of low energy atoms perpendicularly reflected from a surface converter, as a model for atom surface ionization

The influence of collisions with noble gases on spectral lines of hydrogen isotopes

International Nuclear Information System (INIS)

Hermans, P.

1982-01-01

In this thesis measurements on the collisional broadening of the depolarized Rayleigh line and the broadening and shift of the rotational Raman lines (radiative transitions 0→2, 1→3 and 2→4) are presented. The experiments were carried out as a function of temperature from 23 K to 311 K for three systems, viz. H 2 -He, H 2 -Ne and H 2 -Ar. Also results of close coupled calculations on the broadening and shift are presented as a function of temperature for the four spectral lines mentioned. The calculations were performed for two systems, viz H 2 -He and H 2 -Ne. For the system H 2 -He two interaction potentials were used as a starting point, and a comparison between these potentials was made. Now that it is possible to do computations on effects related to the non-spherical interaction of the pure hydrogen isotopes, the availability of experimental data is of great importance. Many experiments on these effects have been performed over the last two decades, but their results are scattered throughout the literature. Therefore, in the last chapter of this thesis the experimental results for the pure hydrogen isotopes and in mixtures with noble gases are compiled to serve as comparing material for the calculations. The presentation is such that a direct comparison with calculations is facilitated. (Auth.)

Calculation of total cross sections and effective emission coefficients for B5+ collisions with ground-state and excited hydrogen

International Nuclear Information System (INIS)

Guzman, F; Errea, L F; Illescas, Clara; Mendez, L; Pons, B

2010-01-01

Classical and semiclassical calculations of nl-resolved charge exchange cross sections in B 5 + collisions with H(n i ) are performed to compute effective emission coefficients for the n = 7 → n = 6 transition in B 4 + for plasma conditions typical of the ASDEX-U tokamak. For n i = 1, the value of the emission coefficient is larger than that obtained from ADAS database by a factor of 2 at energies of 10 keV amu -1 , but no differences are found at energies above 50 keV amu -1 . For n i = 2, our calculation yields emission coefficients close to those derived from ADAS data from low to high impact energies. The emission coefficients corresponding to B 5 + + H(n i = 3) collisions are of the same order of magnitude as those for n i = 2.

Towards a greener world : hydrogen and fuel cells 2004 conference and trade show. Conference proceedings

International Nuclear Information System (INIS)

2004-01-01

Fuel Cells Canada and the Canadian Hydrogen Association hosted the Hydrogen and Fuel Cells 2004 Conference and Tradeshow in Toronto, Ontario, Canada on September 25-28, 2004. Industry leaders from around the world showcased the latest developments in fuel cell and hydrogen technology, and shared research breakthroughs. The conference focussed on many aspects of hydrogen and fuel cell technology, specifically: hydrogen technology progress, including storage, infrastructure and production; fuel cells, including quality, cost and applications; economics and policy, including government and industry strategies; fuel cell demonstrations, including transportation, micro-fuel cells, and portable power; and, impact on climate change, including health and the Kyoto Accord

ICP-MS with hexapole collision cell for isotope ratio measurements of Ca, Fe, and Se

Energy Technology Data Exchange (ETDEWEB)

Boulyga, S.F. [Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Central Department for Analytical Chemistry, Research Centre Juelich (Germany)

2001-07-01

To avoid mass interferences on analyte ions caused by argon ions and argon molecular ions via reactions with collision gases, an rf hexapole filled with helium and hydrogen has been used in inductively coupled plasma mass spectrometry (ICP-MS), and its performance has been studied. Up to tenfold improvement in sensitivity was observed for heavy elements (m > 100 u), because of better ion transmission through the hexapole ion guide. A reduction of argon ions Ar{sup +} and the molecular ions of argon ArX{sup +} (X = O, Ar) by up to three orders of magnitude was achieved in a hexapole collision cell of an ICP-MS (''Platform ICP'', Micromass, Manchester, UK) as a result of gas-phase reactions with hydrogen when the hexapole bias (HB) was set to 0 V; at an HB of 1.6 V argon, and argon-based ions of masses 40 u, 56 u, and 80 u, were reduced by approximately four, two, and five orders of magnitude, respectively. The signal-to-noise ratio {sup 80}Se/ {sup 40}Ar{sub 2}{sup +} was improved by more than five orders of magnitude under optimized experimental conditions. Dependence of mass discrimination on collision-cell properties was studied in the mass range 10 u (boron) to 238 u (uranium). Isotopic analysis of the elements affected by mass-spectrometric interference, Ca, Fe, and Se, was performed using a Meinhard nebulizer and an ultrasonic nebulizer (USN). The measured isotope ratios were comparable with tabulated values from IUPAC. Precision of 0.26%, 0.19%, and 0.12%, respectively, and accuracy of 0.13% 0.25%, and 0.92%, respectively, was achieved for isotope ratios {sup 44}Ca/ {sup 40}Ca and {sup 56}Fe/{sup 57}Fe in 10 {mu}g L{sup -1} solution nebulized by means of a USN and for {sup 78}Se/{sup 80}Se in 100 {mu}g L{sup -1} solution nebulized by means of a Meinhard nebulizer. (orig.)

Topics in atomic collision theory

CERN Document Server

Geltman, Sydney; Brueckner, Keith A

1969-01-01

Topics in Atomic Collision Theory originated in a course of graduate lectures given at the University of Colorado and at University College in London. It is recommended for students in physics and related fields who are interested in the application of quantum scattering theory to low-energy atomic collision phenomena. No attention is given to the electromagnetic, nuclear, or elementary particle domains. The book is organized into three parts: static field scattering, electron-atom collisions, and atom-atom collisions. These are in the order of increasing physical complexity and hence necessar

Novel Composite Hydrogen-Permeable Membranes for Non-Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide

Energy Technology Data Exchange (ETDEWEB)

Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Guibing Zhao; Sanil John

2006-09-30

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. Several pulsed corona discharge (PCD) reactors have been fabricated and used to dissociate H{sub 2}S into hydrogen and sulfur. Visual observation shows that the corona is not uniform throughout the reactor. The corona is stronger near the top of the reactor in argon, while nitrogen and mixtures of argon or nitrogen with H{sub 2}S produce stronger coronas near the bottom of the reactor. Both of these effects appear to be explainable base on the different electron collision interactions with monatomic versus polyatomic gases. A series of experiments varying reactor operating parameters, including discharge capacitance, pulse frequency, and discharge voltage were performed while maintaining constant power input to the reactor. At constant reactor power input, low capacitance, high pulse frequency, and high voltage operation appear to provide the highest conversion and the highest energy efficiency for H{sub 2}S decomposition. Reaction rates and energy efficiency per H{sub 2}S molecule increase with increasing flow rate, although overall H{sub 2}S conversion decreases at constant power input. Voltage and current waveform analysis is ongoing to determine the fundamental operating characteristics of the reactors. A metal infiltrated porous ceramic membrane was prepared using vanadium as the metal and an alumina tube. Experiments with this type of membrane are continuing, but the results thus far have been consistent with those obtained in previous project years: plasma driven permeation or superpermeability

Understanding the kinetics of sulfate reduction in brines by hydrogen: Progress report

International Nuclear Information System (INIS)

Strachan, D.M.

1988-07-01

Experiments were conducted with mixtures of hydrogen gas and each of PBB1 and PBB3 brines to examine the reduction kinetics of sulfate in high ionic strength solutions. Results from the experiments with brines showed that the kinetics of sulfate reduction is slower in high ionic strength solutions than the kinetics in low ionic strength solutions. However, the kinetic mechanism does not seem to alter the slow kinetics, but the addition of much larger quantities of sulfide, about 40 mM, does accelerate the reduction of sulfate. Since the proposed reaction mechanism for the reduction of sulfate by hydrogen gas involves the reaction of sulfide with sulfate, slow initial kinetics in the absence of sulfide is understandable, but also implies an unknown rate-limiting reaction. Precipitation of calcium sulfate(s) and calcium sulfide may limit the sulfide and sulfate concentrations to low values. The coexistence of anhydrite and oldhamite may indicate a part of the Ca-S-H 2 O that has not yet been investigated. 6 refs., 4 figs., 3 tabs

Final Technical Report: Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project

Energy Technology Data Exchange (ETDEWEB)

Ronald Grasman

2011-12-31

This report summarizes the work conducted under U.S. Department of Energy (DOE) under contract DE-FC36-04GO14285 by Mercedes-Benz & Research Development, North America (MBRDNA), Chrysler, Daimler, Mercedes Benz USA (MBUSA), BP, DTE Energy and NextEnergy to validate fuel cell technologies for infrastructure, transportation as well as assess technology and commercial readiness for the market. The Mercedes Team, together with its partners, tested the technology by operating and fueling hydrogen fuel cell vehicles under real world conditions in varying climate, terrain and driving conditions. Vehicle and infrastructure data was collected to monitor the progress toward the hydrogen vehicle and infrastructure performance targets of $2.00 to 3.00/gge hydrogen production cost and 2,000-hour fuel cell durability. Finally, to prepare the public for a hydrogen economy, outreach activities were designed to promote awareness and acceptance of hydrogen technology. DTE, BP and NextEnergy established hydrogen filling stations using multiple technologies for on-site hydrogen generation, storage and dispensing. DTE established a hydrogen station in Southfield, Michigan while NextEnergy and BP worked together to construct one hydrogen station in Detroit. BP constructed another fueling station in Burbank, California and provided a full-time hydrogen trailer at San Francisco, California and a hydrogen station located at Los Angeles International Airport in Southern, California. Stations were operated between 2005 and 2011. The Team deployed 30 Gen I Fuel Cell Vehicles (FCVs) in the beginning of the project. While 28 Gen I F-CELLs used the A-Class platform, the remaining 2 were Sprinter delivery vans. Fuel cell vehicles were operated by external customers for real-world operations in various regions (ecosystems) to capture various driving patterns and climate conditions (hot, moderate and cold). External operators consisted of F-CELL partner organizations in California and Michigan

Application of railgun principle to high-velocity hydrogen pellet injection for magnetic fusion reactor fueling

International Nuclear Information System (INIS)

Kim, K.; Zhang, J.

1992-01-01

Three separate papers are included which report research progress during this period: (1) A new railgun configuration with perforated sidewalls, (2) development of a fuseless small-bore railgun for injection of high-speed hydrogen pellets into magnetically confined plasmas, and (3) controls and diagnostics on a fuseless railgun for solid hydrogen pellet injection

Flavour tagging of $b$ mesons in $pp$ collisions at LHCb

CERN Multimedia

Mueller, Vanessa

2016-01-01

Flavour tagging, i.e. the inference of the production flavour of reconstructed $b$ hadrons, is essential for precision measurements of decay time-dependent $CP$ violation and of mixing parameters in the the neutral $B$ meson systems. LHC's $pp$ collisions with their high track multiplicities constitute a challenging environment for flavour tagging and demand for new and improved strategies. We present recent progress and new developments in flavour tagging at the LHCb experiment, which will allow for a further improvement of $CP$ violation measurements in decays of $B^0$ and $B_s^0$ mesons.

Radiations from atomic collision processes

International Nuclear Information System (INIS)

Bernyi, D.

1994-01-01

The physics of atomic collision phenomena in which only the Coulomb forces have a role is an actual field or the research of the present days. The impact energy range in these collisions is very broad,it extends from the eV or even lower region to the GeV region or higher,i.e. it spans the region of three branches of physics,namely that of the atomic,the nuclear and the particle physics.To describe and explain the collision processes themselves, different models (collision mechanisms) are used and they are surveyed in the presentation. Different electromagnetic radiations and particles are emitted from the collision processes.Their features are shown in details together with the most important methods in their detection and study.Examples are given based on the literature and on the investigations of the author and his coworkers. The applications of the radiation from atomic collisions in other scientific fields and in the solution of different practical problems are also surveyed shortly. 16 figs., 2 tabs., 76 refs. (author)

Large-scale hydrogen production using nuclear reactors

Energy Technology Data Exchange (ETDEWEB)

Ryland, D.; Stolberg, L.; Kettner, A.; Gnanapragasam, N.; Suppiah, S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2014-07-01

For many years, Atomic Energy of Canada Limited (AECL) has been studying the feasibility of using nuclear reactors, such as the Supercritical Water-cooled Reactor, as an energy source for large scale hydrogen production processes such as High Temperature Steam Electrolysis and the Copper-Chlorine thermochemical cycle. Recent progress includes the augmentation of AECL's experimental capabilities by the construction of experimental systems to test high temperature steam electrolysis button cells at ambient pressure and temperatures up to 850{sup o}C and CuCl/HCl electrolysis cells at pressures up to 7 bar and temperatures up to 100{sup o}C. In parallel, detailed models of solid oxide electrolysis cells and the CuCl/HCl electrolysis cell are being refined and validated using experimental data. Process models are also under development to assess options for economic integration of these hydrogen production processes with nuclear reactors. Options for large-scale energy storage, including hydrogen storage, are also under study. (author)

Charge transfer and ionization in collisions of Si3+ with H from low to high energy

Science.gov (United States)

Wang, J. G.; He, B.; Ning, Y.; Liu, C. L.; Yan, J.; Stancil, P. C.; Schultz, D. R.

2006-11-01

Charge transfer processes due to collisions of ground state Si3+(3sS1) ions with atomic hydrogen are investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) and classical-trajectory Monte Carlo (CTMC) methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained from Herrero [J. Phys. B 29, 5583 (1996)] which were calculated with a full configuration-interaction method. Total and state-selective single-electron capture cross sections are obtained for collision energies from 0.01eV/u to 1MeV/u . Total and state-selective rate coefficients are also presented for temperatures from 2×103K to 107K . Comparison with existing data reveals that the total CTMC cross sections are in good agreement with the experimental measurements at the higher considered energies and that previous Landau-Zener calculations underestimate the total rate coefficients by a factor of up to two. The CTMC calculations of target ionization are presented for high energies.

Sources of polarized negative ions: progress and prospects

International Nuclear Information System (INIS)

Haeberli, W.

1980-01-01

A summary of recent progress in the art of producing beams of polarized ions is given. In all sources of polarized ions, one first produces (or selects) neutral atoms which are polarized in electron spin. Those types of sources which use a beam of thermal polarized hydrogen atoms are discussed. Progress made in the preparation of the atomic beam and the methods used to convert the neutral atoms to polarized ions is summarized. The second type of source discussed is based on fast (keV) polarized hydrogen atoms. Conversion to negative ions is very simple because one only needs to pass the fast atoms through a suitable charge exchange medium (gas or vapor). However, the production of the polarized atoms is more difficult in this case. The proposal to employ polarized alkali vapor to form a beam of polarized fast H atoms, where the polarized alkali atoms are produced either by an atomic beam apparatus or by optical pumping is discussed

Kinetics of hydrogen in chromospheres of red dwarfs

International Nuclear Information System (INIS)

Bruevich, E.A.; Katsova, M.M.; Livshits, M.A.; AN SSSR, Moscow

1990-01-01

A method is suggested and solution is conducted of the stationary equations for an 8-level hydrogen atom with an approximate account for lines radiative transfer in an optically thick layer. Ionization and excitation of hydrogen atoms are caused by electron collisions; the influence of photospheric radiation was neglected. The medium stays motionless, and the photon escape from the layer is connected with gradual diffusion in frequency during multiple scatterings. Mean over the layer probabilities of photon escape are introduced into the stationary equations. They are determined for a finite-thickness layer with an uniform distribution of primary photon sources and with an absorption coefficient accounting for Stark and Doppler effects. As an example of application of the calculations, an interpretation is presented of the data on the Balmer decrement in the maximum of the stellar flare of YZ CMi on March 4, 1985. It is shown that the transition from a steep Balmer decrement to a mildly sloping one is due to a decrease of the photon escape probability in the higher members of Balmer series, i.e. the lines later than H γ

Translational Entanglement and Teleportation of Matter Wavepackets by Collisions and Half-Collisions

Science.gov (United States)

Fisch, L.; Tal, A.; Kurizki, G.

To date, the translationally-entangled state originally proposed by Einstein, Podolsky and Rosen (EPR) in 1935 has not been experimentally realized for massive particles. Opatrný and Kurizki [Phys. Rev. Lett. 86, 3180 (2000)] have suggested the creation of a position- and momentum-correlated, i.e., translationally-entangled, pair of particles approximating the EPR state by dissociation of cold diatomic molecules, and further manipulation of the EPR pair effecting matter-wave teleportation. Here we aim at setting the principles of and quantifying translational entanglement by collisions and half-collisions. In collisions, the resonance width s and the initial phase-space distributions are shown to determine the degree of post-collisional momentum entanglement. Half-collisions (dissociation) are shown to yield different types of approximate EPR states. We analyse a feasible realization of translational EPR entanglement and teleportation via cold-molecule Raman dissociation and subsequent collisions, resolving both practical and conceptual difficulties it has faced so far: How to avoid entanglement loss due to the wavepacket spreading of the dissociation fragments? How to measure both position and momentum correlations of the dissociation fragments with sufficient accuracy to verify their EPR correlations? How to reliably perform two-particle (Bell) position and momentum measurements on one of the fragments and the wavepacket to be teleported?

NA49: lead-lead collision

CERN Multimedia

1996-01-01

This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

From collisions to clusters

DEFF Research Database (Denmark)

Loukonen, Ville; Bork, Nicolai; Vehkamaki, Hanna

2014-01-01

-principles molecular dynamics collision simulations of (sulphuric acid)1(water)0, 1 + (dimethylamine) → (sulphuric acid)1(dimethylamine)1(water)0, 1 cluster formation processes. The simulations indicate that the sticking factor in the collisions is unity: the interaction between the molecules is strong enough...... control. As a consequence, the clusters show very dynamic ion pair structure, which differs from both the static structure optimisation calculations and the equilibrium first-principles molecular dynamics simulations. In some of the simulation runs, water mediates the proton transfer by acting as a proton...... to overcome the possible initial non-optimal collision orientations. No post-collisional cluster break up is observed. The reasons for the efficient clustering are (i) the proton transfer reaction which takes place in each of the collision simulations and (ii) the subsequent competition over the proton...

Absolute fragmentation cross sections in atom-molecule collisions: Scaling laws for non-statistical fragmentation of polycyclic aromatic hydrocarbon molecules

Energy Technology Data Exchange (ETDEWEB)

Chen, T.; Gatchell, M.; Stockett, M. H.; Alexander, J. D.; Schmidt, H. T.; Cederquist, H.; Zettergren, H., E-mail: henning@fysik.su.se [Department of Physics, Stockholm University, S-106 91 Stockholm (Sweden); Zhang, Y. [Department of Mathematics, Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Rousseau, P.; Maclot, S.; Delaunay, R.; Adoui, L. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen Cedex 05 (France); Université de Caen Basse-Normandie, Esplanade de la Paix, F-14032 Caen (France); Domaracka, A.; Huber, B. A. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen Cedex 05 (France); Schlathölter, T. [Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen (Netherlands)

2014-06-14

We present scaling laws for absolute cross sections for non-statistical fragmentation in collisions between Polycyclic Aromatic Hydrocarbons (PAH/PAH{sup +}) and hydrogen or helium atoms with kinetic energies ranging from 50 eV to 10 keV. Further, we calculate the total fragmentation cross sections (including statistical fragmentation) for 110 eV PAH/PAH{sup +} + He collisions, and show that they compare well with experimental results. We demonstrate that non-statistical fragmentation becomes dominant for large PAHs and that it yields highly reactive fragments forming strong covalent bonds with atoms (H and N) and molecules (C{sub 6}H{sub 5}). Thus nonstatistical fragmentation may be an effective initial step in the formation of, e.g., Polycyclic Aromatic Nitrogen Heterocycles (PANHs). This relates to recent discussions on the evolution of PAHNs in space and the reactivities of defect graphene structures.

Kinematically complete study on electron impact ionisation of aligned hydrogen molecules

Energy Technology Data Exchange (ETDEWEB)

Senftleben, Arne

2009-10-28

Within the work presented here, single ionisation of spatially aligned hydrogen molecules by 200 eV electrons was studied in a kinematically complete experiment. For the first time, a comprehensive set of fully differential cross sections (FDCS) was obtained for this process on a molecular target. The direction of the internuclear axis was derived from the fragment emission of post-collision dissociation of the residual H{sub 2}{sup +} ion. Therefore, a protonic fragment was detected in coincidence with the two final-state electrons using a dedicated reaction microscope and sophisticated data analysis. For direct ionisation into the ionic ground state, existing theoretical cross sections for aligned molecules were tested. Additionally, we observed molecular frame angular distributions of Auger electrons emitted through dissociative autoionisation of H{sub 2}. Earlier findings of kinematically incomplete experiments were reproduced, but the FDCS reveal structures so far unknown. Furthermore, for random alignment, differential cross sections at two distinct values of the mean internuclear distance were obtained, providing new arguments in the current discussion on the nature of discrepancies observed between atomic and molecular collisions. (orig.)

The role of CFD computer analyses in hydrogen safety management

International Nuclear Information System (INIS)

Komen, E.M.J; Visser, D.C; Roelofs, F.; Te Lintelo, J.G.T

2014-01-01

The risks of hydrogen release and combustion during a severe accident in a light water reactor have attracted considerable attention after the Fukushima accident in Japan. Reliable computer analyses are needed for the optimal design of hydrogen mitigation systems, like e.g. passive autocatalytic recombiners (PARs), and for the assessment of the associated residual risk of hydrogen combustion. Traditionally, so-called Lumped Parameter (LP) computer codes are being used for these purposes. In the last decade, significant progress has been made in the development, validation, and application of more detailed, three-dimensional Computational Fluid Dynamics (CFD) simulations for hydrogen safety analyses. The objective of the current paper is to address the following questions: - When are CFD computer analyses needed complementary to the traditional LP code analyses for hydrogen safety management? - What is the validation status of the CFD computer code for hydrogen distribution, mitigation, and combustion analyses? - Can CFD computer analyses nowadays be executed in practical and reliable way for full scale containments? The validation status and reliability of CFD code simulations will be illustrated by validation analyses performed for experiments executed in the PANDA, THAI, and ENACCEF facilities. (authors)

Studies of relativistic heavy ion collisions

International Nuclear Information System (INIS)

Madansky, L.

1989-01-01

This report presents the progress in our program of Relativistic Heavy Ion studies. The first phase of experiments on lepton pairs is almost complete and the results from the initial part of this program are presented in copies of three publications. It appears that the origin of lepton pairs is the annihilation of pions. The evidence for this seems to be the shape of the dilepton mass spectrum, the cross-section as a function of energy which seems to scale with pion production, and the general kinematic behavior of the lepton pairs themselves. We present progress on the development of Ring Imaging Cerenkov counters for dilepton observations in general, and a short report on a high resolution method counter proposal that could be adapted to RHIC counters in general. Publication of results on hyperon polarization with incident polarized proton beams is also presented. These results use the phenomenological approach that could be useful in understanding hyperon production in heavy ion collisions. In this connection, a proposal for studying high density nuclear matter with incident antiprotons is presented. Progress on the TPC detectors developed by the BNL group for heavy ion research is reported, along with recent analysis of polarization with incident silicon beams. Finally, the most recent results on subthreshold antiproton production is presented. These latter results are several orders of magnitude more than expected and they point to some kind of coherent hadronic phenomena even at extremely low energies

Alternative energies. Updates on progress

Energy Technology Data Exchange (ETDEWEB)

Ferreira, German (ed.) [CIRCE - Centre of Research for Energy Resources and Consumption, Zaragoza (Spain)

2013-07-01

Presents fundamental and applied research of alternative energies. Address key pillars in the alternative energy field, such as: biomass energy, hydrogen energy, solar energy, wind energy, hydroelectric power, geothermal energy and their environmental implications, with the most updated progress. Includes the life cycle assessment and thermoeconomic analysis as tools for evaluating and optimising environmental and cost subjects. This book presents nine chapters based on fundamental and applied research of alternative energies. At the present time, the challenge is that technology has to come up with solutions that can provide environmentally friendly energy supply options that are able to cover the current world energy demand. Experts around the world are working on these issues for providing new solutions that will break the existing technological barriers. This book aims to address key pillars in the alternative energy field, such as: biomass energy, hydrogen energy, solar energy, wind energy, hydroelectric power, geothermal energy and their environmental implications, with the most updated progress for each pillar. It also includes the life cycle assessment (LCA) and thermoeconomic analysis (TA) as tools for evaluating and optimising environmental and cost subjects. Chapters are organized into fundamental research, applied research and future trends; and written for engineers, academic researches and scientists.

Inclusive LAMBDA production in sigma-proton collisions at 23 GeV/c

International Nuclear Information System (INIS)

Arik, E.

1976-01-01

Inclusive Λ 0 production resulting from Σ - -proton collisions was studied in the Brookhaven National Laboratory -AGS negative hyperon beam. The experiment consisted of scattering Σ - particles of momentum equal to 23 Gev/c on a liquid hydrogen target. The differential cross section was obtained as a function of missing mass squared and four-momentum transfer from the Σ - to the Λ 0 . The fit made to the predicted form of the differential cross section in the triple-Regge region indicates that this reaction is mediated by a virtual pion emission between the Σ - and p. The combination of Σ - Λ 0 π and Σ - Σ 0 π coupling constants was also determined

The epidemiology of bicyclist's collision accidents

DEFF Research Database (Denmark)

Larsen, L. B.

1994-01-01

of bicyclists and risk situations. The findings should make a basis for preventive programmes in order to decrease the number and severity of bicyclists collision accidents. Data from the emergency room in a 2 year period was combined with data from questionnaires. The study group consisted of 1021 bicyclists......The number of bicyclists injured in the road traffic in collision accidents and treated at the emergency room at Odense University Hospital has increased 66% from 1980 to 1989. The aim of this study was to examine the epidemiology of bicyclist's collision accidents and identify risk groups...... injured in collision accidents, and 1502 bicyclists injured in single accidents was used as a reference group. The young bicyclists 10-19 years of age had the highest incidence of injuries caused by collision accidents. The collision accidents had different characteristics according to counterpart. One...

Multiscale study on hydrogen mobility in metallic fusion divertor material

International Nuclear Information System (INIS)

Heinola, K.

2010-01-01

trapping to vacancies and surfaces. Results from the energetics of pure tungsten defects were used in the development of an classical bond-order potential for describing the tungsten defects to be used in molecular dynamics simulations. The developed potential was utilized in determination of the defect clustering and annihilation properties. These results were further employed in binary collision and rate theory calculations to determine the evolution of large defect clusters that trap hydrogen in the course of implantation. The computational results for the defect and trapped hydrogen concentrations were successfully compared with the experimental results. With the aforedescribed multiscale analysis the experimental results within this thesis and found in the literature were explained both quantitatively and qualitatively. (orig.)

Dynamic Monte-Carlo modeling of hydrogen retention and chemical erosion from Tore Supra deposits

International Nuclear Information System (INIS)

Rai, A.; Schneider, R.; Warrier, M.; Roubin, P.; Martin, C.

2009-01-01

A multi-scale model has been developed to study the hydrogen retention [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. 374 (2008) 304] and chemical erosion of porous graphite. To model the chemical erosion process due to thermal hydrogen ions, Kueppers cycle [J. Kueppers, Surf. Sci. Rep. 22 (1995) 249; M. Wittmann, J. Kueppers, J. Nucl. Mater. 227 (1996) 186] has been introduced. The model is applied to study hydrogen transport in deposits collected from the leading edge of neutralizers of Tore Supra. The effect of internal structure on chemical erosion is studied. The MD study [E. Salonen et al., J. Nucl. Mater. 290-293 (2001) 144] shows that the experimentally observed decrease of erosion yield at higher fluxes is due to the decrease of carbon collision cross-section at a surface due to shielding by hydrogen atom already present on the surface. Inspired by this study, a simple multi-scale model is developed to describe the flux dependence of chemical erosion. The idea is to use the local chemistry effect from the Kueppers model to calculate the hydrocarbon molecule formation process and then to find the release probability of the produced hydrocarbon based on the purely geometrical constraints. The model represents quite well the trends in experimental data.

Review of thermodinamic and mechanical properties of hydrogen-transition metal systems

International Nuclear Information System (INIS)

Mathias, H.; Katz, Y.

1978-04-01

A large body of fundamental and empirical knowledge has been acquired during many years of research concerning the interactions between hydrogen and metals, the location of hydrogen in metal structures, its mobility in metals and its influence on mechanical properties of metals. Much progress has been made in the understanding of related phenomena, and various theories have been proposed, but considerable disagreement still exist about basic mechanisms involved. The growing interest in these subjects and their important role in science and technology are well documented by many reviews and symposia. A general survey of these topics with reference to experimental results and theories related to thermodynamic and mechanical properties of hydrogen-transition metal systems, such as H-Pd, H-Ti, H-Fe etc. is given in the present review. Special emphasis is given to hydrogen embrittlement of metals

Quantum dynamics of the Eley-Rideal hydrogen formation reaction on graphite at typical interstellar cloud conditions.

Science.gov (United States)

Casolo, Simone; Martinazzo, Rocco; Bonfanti, Matteo; Tantardini, Gian Franco

2009-12-31

Eley-Rideal formation of hydrogen molecules on graphite, as well as competing collision induced processes, are investigated quantum dynamically at typical interstellar cloud conditions, focusing in particular on gas-phase temperatures below 100 K, where much of the chemistry of the so-called diffuse clouds takes place on the surface of bare carbonaceous dust grains. Collisions of gas-phase hydrogen atoms with both chemisorbed and physisorbed species are considered using available potential energy surfaces (Sha et al., J. Chem. Phys.2002 116, 7158), and state-to-state, energy-resolved cross sections are computed for a number of initial vibrational states of the hydrogen atoms bound to the surface. Results show that (i) product molecules are internally hot in both cases, with vibrational distributions sharply peaked around few (one or two) vibrational levels, and (ii) cross sections for chemisorbed species are 2-3x smaller than those for physisorbed ones. In particular, we find that H(2) formation cross sections out of chemically bound species decrease steadily when the temperature drops below approximately 1000 K, and this is likely due to a quantum reflection phenomenon. This suggests that such Eley-Rideal reaction is all but efficient in the relevant gas-phase temperature range, even when gas-phase H atoms happen to chemisorb barrierless to the surface as observed, e.g., for forming so-called para dimers. Comparison with results from classical trajectory calculations highlights the need of a quantum description of the dynamics in the astrophysically relevant energy range, whereas preliminary results of an extensive first-principles investigation of the reaction energetics reveal the importance of the adopted substrate model.

Hydrogen energy

International Nuclear Information System (INIS)

2005-03-01

This book consists of seven chapters, which deals with hydrogen energy with discover and using of hydrogen, Korean plan for hydrogen economy and background, manufacturing technique on hydrogen like classification and hydrogen manufacture by water splitting, hydrogen storage technique with need and method, hydrogen using technique like fuel cell, hydrogen engine, international trend on involving hydrogen economy, technical current for infrastructure such as hydrogen station and price, regulation, standard, prospect and education for hydrogen safety and system. It has an appendix on related organization with hydrogen and fuel cell.

Technical Integration of Nuclear Hydrogen Production Technology

International Nuclear Information System (INIS)

Lee, Ki Young; Park, J. K.; Chang, J. H.

2009-04-01

These works focus on the development of attainment indices for nuclear hydrogen key technologies, the analysis of the hydrogen production process and the performance estimation for hydrogen production systems, and the assessment of the nuclear hydrogen production cost. For assessing the degree of attainments in comparison with the final goals of VHTR technologies in progress of researches, subdivided are the prerequisite items confirmed to the NHDD concepts. We developed and applied R and D quality management methodology to meet 'Development of Key Technologies for Nuclear Hydrogen' project. And we also distributed R and D QAM and R and D QAP to each teams and are in operation. The preconceptual flow diagrams of SI, HTSE, and HyS processes are introduced and their material and energy balances have been proposed. The hydrogen production thermal efficiencies of not only the SI process as a reference process but also the HTSE and HyS processes were also estimated. Technical feasibility assessments of SI, HTSE, and HyS processes have been carried out by using the pair-wise comparison and analytic hierarchy process, and it is revealed that the experts are considering the SI process as the most feasible process. The secondary helium pathway across the SI process is introduced. Dynamic simulation codes for the H2S04vaporizer, sulfuric acid and sulfur trioxide decomposers, and HI decomposer on the secondary helium pathway and for the primary and secondary sulfuric acid distillation columns, HIx solution distillation column, and preheater for HI vapor have been developed and integrated

Photon collisions as a glueball source

International Nuclear Information System (INIS)

Liu, H.C.

1984-01-01

Photon-photon and photon-nucleon collisions are suggested as a glueball source at small x in the collision center-of-mass frame. The glueball-production cross section is estimated through the two-gluon-fusion mechanism in perturbative quantum chromodynamics. The pointlike component of the photon structure function has a distinctive feature in that it consists almost purely of gluons at small x, which turns out to be very effective in producing glueballs. A much larger signal-to-noise ratio is expected in the glueball search in high-energy photon-photon and photon-nucleon collisions compared with hadron-hadron collisions. It is argued that the background due to soft collisions of the photons can be effectively reduced

Synthesis and Catalytic Hydrogen Transfer Reaction of Ruthenium(II) Complex

Energy Technology Data Exchange (ETDEWEB)

Son, Jung Ik; Kim, Aram; Noh, Hui Bog; Lee, Hyun Ju; Shim, Yoon Bo; Park, Kang Hyun [Pusan National University, Busan (Korea, Republic of)

2012-01-15

The ruthenium(II) complex [Ru(bpy){sub 2}-(PhenTPy)] was synthesized, and used for the transfer hydrogenation of ketones and the desired products were obtained in good yield. Based on the presented results, transition-metal complexes can be used as catalysts for a wide range of organic transformations. The relationship between the electro-reduction current density and temperature are being examined in this laboratory. Attempts to improve the catalytic activity and determine the transfer hydrogenation mechanism are currently in progress. The catalytic hydrogenation of a ketone is a basic and critical process for making many types of alcohols used as the final products and precursors in the pharmaceutical, agrochemical, flavor, fragrance, materials, and fine chemicals industries. The catalytic hydrogenation process developed by Noyori is a very attractive process. Formic acid and 2-propanol have been used extensively as hydrogenation sources. The advantage of using 2-propanol as a hydrogen source is that the only side product will be acetone, which can be removed easily during the workup process. Hydrogen transfer (HT) catalysis, which generates alcohols through the reduction of ketones, is an attractive protocol that is used widely. Ruthenium(II) complexes are the most useful catalysts for the hydrogen transfer (HT) of ketones. In this method, a highly active catalytic system employs a transition metal as a catalyst to synthesize alcohols, and is a replacement for the hydrogen-using hydrogenation process. The most active system is based on Ru, Rh and Ir, which includes a nitrogen ligand that facilitates the formation of a catalytically active hydride and phosphorus.

Synthesis and Catalytic Hydrogen Transfer Reaction of Ruthenium(II) Complex

International Nuclear Information System (INIS)

Son, Jung Ik; Kim, Aram; Noh, Hui Bog; Lee, Hyun Ju; Shim, Yoon Bo; Park, Kang Hyun

2012-01-01

The ruthenium(II) complex [Ru(bpy) 2 -(PhenTPy)] was synthesized, and used for the transfer hydrogenation of ketones and the desired products were obtained in good yield. Based on the presented results, transition-metal complexes can be used as catalysts for a wide range of organic transformations. The relationship between the electro-reduction current density and temperature are being examined in this laboratory. Attempts to improve the catalytic activity and determine the transfer hydrogenation mechanism are currently in progress. The catalytic hydrogenation of a ketone is a basic and critical process for making many types of alcohols used as the final products and precursors in the pharmaceutical, agrochemical, flavor, fragrance, materials, and fine chemicals industries. The catalytic hydrogenation process developed by Noyori is a very attractive process. Formic acid and 2-propanol have been used extensively as hydrogenation sources. The advantage of using 2-propanol as a hydrogen source is that the only side product will be acetone, which can be removed easily during the workup process. Hydrogen transfer (HT) catalysis, which generates alcohols through the reduction of ketones, is an attractive protocol that is used widely. Ruthenium(II) complexes are the most useful catalysts for the hydrogen transfer (HT) of ketones. In this method, a highly active catalytic system employs a transition metal as a catalyst to synthesize alcohols, and is a replacement for the hydrogen-using hydrogenation process. The most active system is based on Ru, Rh and Ir, which includes a nitrogen ligand that facilitates the formation of a catalytically active hydride and phosphorus

Relativistic heavy ion collisions. Final report, May 1, 1993-April 30, 1996

International Nuclear Information System (INIS)

1996-01-01

The research program supported by the Nuclear Physics Division of DOE started in May 1991. The present three year period is from May 1, 1993 to April 30, 1996. This progress report summarizes the work done during this period. The main topics covered in this report are: quark-hadron phase transitions; particle production by soft interaction in hadronic and nuclear collisions; quantum chromodynamics; charm production; chaos in non-abelian gauge theory; quark-gluon plasma 2; and comments on training of young physicists

Bubble collisions in general relativity

International Nuclear Information System (INIS)

Siklos, S.T.C.; Wu, Z.C.; University of Science and Technology of China, Hofei, Anhwei)

1983-01-01

The collision of two bubbles of true vacuum in a background of false vacuum is considered in the context of General Relativity. It is found that in the thin wall approximation, the problem, can be solved exactly. The region to the future of the collision is described by the pseudo-Schwarzschild de Sitter metric. The parameters in this metric are found by solving the junction conditions at each collision. (author)

CHARACTERIZATION OF WILD PIG VEHICLE COLLISIONS

Energy Technology Data Exchange (ETDEWEB)

Mayer, J; Paul E. Johns, P

2007-05-23

Wild pig (Sus scrofa) collisions with vehicles are known to occur in the United States, but only minimal information describing these accidents has been reported. In an effort to better characterize these accidents, data were collected from 179 wild pig-vehicle collisions from a location in west central South Carolina. Data included accident parameters pertaining to the animals involved, time, location, and human impacts. The age structure of the animals involved was significantly older than that found in the population. Most collisions involved single animals; however, up to seven animals were involved in individual accidents. As the number of animals per collision increased, the age and body mass of the individuals involved decreased. The percentage of males was significantly higher in the single-animal accidents. Annual attrition due to vehicle collisions averaged 0.8 percent of the population. Wild pig-vehicle collisions occurred year-round and throughout the 24-hour daily time period. Most accidents were at night. The presence of lateral barriers was significantly more frequent at the collision locations. Human injuries were infrequent but potentially serious. The mean vehicle damage estimate was $1,173.

New opportunity for hydrogen fuelled vehicles

International Nuclear Information System (INIS)

Krepec, T.; Hong, H.

1998-01-01

The present case study is showing that with recent developments in automotive technology, the concept of a hydrogen hybrid electric vehicle with a range of 300 km is feasible. To extend this range, more progress must be made in the batteries and in the gas tanks, as well as in automobile materials and structure to lower the weight of the vehicle. Regarding a possible commercialization of HHEV, the greatest obstacles are: the cost of the fuel, the refueling infrastructure and the public acceptance of hydrogens as the fuel for cars, taking into account some negative perception related to the past history of accidents with hydrogen. Still, the deciding factor in the acceptance of HHEV's might be the society's desire for zero emission vehicles supported by subsidies towards ZEV's from higher taxation of gasoline. One more aspect of hydrogen car should be discussed here. It is the recently, by Chrysler unveiled, new fuel cell car supplied with gasoline which is scheduled for production in 2005. While it is a step in the right direction, several doubts remain: (1) it will be an LEV not a ZEV, (2) it will produce CO 2 , contributing to greenhouse effect, (3) it will use a not renewable energy source, and as such it can be considered only as a mid-solution to the environmental and energy crisis. 3 refs

High energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Bhalla, K.B.

1980-01-01

An attempt is made to explain nucleus-nucleus collisions based on nuclear emulsion experiments. Peripheral and central collisions are described in detail. Assuming the fireball model, the concepts of geometry, kinematics and thermodynamics in this model are discussed. Projectile and target fragmentations are studied. The advantages of using nuclear emulsions as detectors, are mentioned. Proton-nucleus collisions and nucleus-nucleus collisions are compared. Interactions, of projectiles such as Ca, B and C on targets such as Pb, Ag, Br etc. at very high energies (approximately 300 to 1700 Gev) are listed. A comparison of the near multiplicities in these interactions is given. A generalized explanation is given on the processes involved in these interactions. (A.K.)

Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

Science.gov (United States)

Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

2017-01-01

Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

Theoretical studies of highly ionized species. Progress report, March 1, 1982-February 28, 1985

International Nuclear Information System (INIS)

Dalgarno, A.

1984-08-01

A considerable part of our research efforts since March 1, 1982, has been given to the description and analysis of our extensive calculations of the cross sections for charge transfer of multiply charged ions in collision with atomic hydrogen. Our calculations employed a diabatic formulation (Heil, Butler and Dalgarno 1981). The construction of the diabatic potentials and diabatic coupling matrix elements and the resulting cross sections at thermal energies are presented in another paper (Heil, Butler and Dalgarno 1983). 14 references

Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

Energy Technology Data Exchange (ETDEWEB)

Chacon Velasco, A.J. [Universidad de Pamplona, Pamplona (Colombia); Dougar-Jabon, V.D. [Universidad Industrial de Santander, Bucaramanga (Colombia)

2004-07-01

In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H{sup -} and D{sup -} ion production involves the process of high Rydberg state excitation. (authors)

Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

International Nuclear Information System (INIS)

Chacon Velasco, A.J.; Dougar-Jabon, V.D.

2004-01-01

In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H - and D - ion production involves the process of high Rydberg state excitation. (authors)

High energy hadron-hadron collisions

International Nuclear Information System (INIS)

Chou, T.T.

1990-01-01

Results of a study on high energy collision with the geometrical model are summarized in three parts: (i) the elastic hadron-hadron collision, (ii) the inelastic hadron-hadron collision, and (iii) the e + e - annihilation. The geometrical description of high-energy elastic scattering developed earlier is still in general agreement with experiments at the CERN-S bar ppS energies. A simple one-parameter expression for the blackness of bar pp system has been proposed recently which describes very well all existing data from ISR to S bar ppS energies. The geometrical description has also been extended to include processes of fragmentation and diffraction dissociation and other phenomena. In the past five years, a unified physical picture for multiparticle emission in hadron-hadron and e + e - collisions was developed. It focuses on the idea of the wide range of values for the total angular momentum in hadron-hadron collisions. An extension of this consideration yields a theory for the momentum distribution of the outgoing particles which agrees with bar pp and e + e - collision experiments. The results and conclusions of this theory have been extrapolated to higher energies and yielded many predictions which can be experimentally tested. 37 refs

State resolved rotational excitation cross-sections and rates in H2 + H2 collisions

International Nuclear Information System (INIS)

Sultanov, Renat A.; Guster, Dennis

2006-01-01

Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H 2 -H 2 system are used from the following works: [A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J. Peterson, J. Chem. Phys., 116 (2002) 666; P. Diep, J.K. Johnson, J. Chem. Phys., 113 (2000) 3480; P. Diep, J.K. Johnson, J. Chem. Phys., 112 (2000) 4465]. Cross-sections for rotational transitions 00 → 20, 22, 40, 42, 44 and corresponding rate coefficients are calculated using a quantum-mechanical approach. Results are compared for a wide range of kinetic temperatures 300 K ≤ T≤ 3000 K

Quasi-free scattering in the ionization and destruction of hydrogen and helium Rydberg atoms in collision with neutral targets

International Nuclear Information System (INIS)

Renwick, S.P.

1992-01-01

Hydrogen and helium Rydberg atoms (H** and He**), with principal quantum number n ranging from 10 to 20, have been used in collision experiments from 1 to 40 keV/amu. These were produced by electron capture in a charge-exchange cell and analyzed by ionization in a modulated electric field combined with phase-sensitive detection. Three experiments have been conducted. In the first, spectra of the band of H and He Rydberg states from electron capture were produced by the modulated field technique and compared. Considerable differences were found between the two. Both types of spectra were analyzed with calculations of Stark energies and field ionization rates. Attempts were made to simulate the spectra using this information and some assumptions about the state distribution produced in the electron capture. In the second experiment, destruction cross sections for H** incident on N 2 , Ar, and SF 6 were measured. This was a further test of the independent-particle model for Rydberg atom scattering; in this model, the atom is destroyed by quasi-free scattering of either the ionic core or the outer electron. Already proven valid for n = 20-35, this has been extended to n as low as 10, as measurements with n = 10 showed full compliance with the model. In the third experiment, not only destruction cross sections but also ionization cross sections for H** and He** incident on Xe, AR, and N 2 were measured. The ionization measurement is a more sensitive test of the quasi-free scattering of the Rydberg electron. This was especially important for the Xe and Ar targets, which exhibits a Ramsauer-Townsend minimum in their free-electron scattering cross sections. The quasi-free Rydberg electron should reproduce these data. Unmistakable deviations from the quasi-free prediction were seen in Xe and N 2 but not in Ar. This represents the first measurement of a breakdown of the Independent Particle Model for fast Rydberg atom scattering

Studies in chemical dynamics and radiation chemistry. Technical progress report, 1 July 1974--30 June 1975

International Nuclear Information System (INIS)

Kuppermann, A.

1975-01-01

Research progress in the following areas is reported: low energy electron scattering; photoelectron spectrometry; elementary reactions by photolysis at variable wavelengths; collisions in crossed molecular beams; and, diffusion kinetics in the radiation chemistry of water. Publications related to the work are included. (JGB)

The Palm Desert renewable [hydrogen] transportation system

Energy Technology Data Exchange (ETDEWEB)

Chamberlin, C.E.; Lehman, P. [Humboldt State Univ., Arcata, CA (United States). Schatz Energy Research Center

1998-08-01

This paper describes the Schatz Energy Research Center (SERC) progress on the Palm Desert Renewable Hydrogen Transportation System Project for the period June 1997 through May 1998. The project began in March 1996. The goal of the Palm Desert Project is to develop a clean and sustainable transportation system for a community. The project demonstrates the practical utility of hydrogen as a transportation fuel and the proton exchange membrane (PEM) fuel cell as a vehicle power system. The project includes designing and building 4 fuel cell powered vehicles, a solar hydrogen generating and refueling station, and a fuel cell vehicle diagnostic center. Over this last year, SERC has built a fuel cell powered neighborhood electric vehicle and delivered it to the City of Palm Desert. The design of the hydrogen refueling station is near completion and it is anticipated that construction will be complete in the fall of 1998. The vehicles are currently being refueled at a temporary refueling station. The diagnostic center is being designed and maintenance procedures as well as computer diagnostic programs for the fuel cell vehicles are being developed. City employees are driving the vehicles daily and monitoring data are being collected. The drivers are pleased with the performance of the vehicles.

IHCE '95. International Hydrogen and Clean Energy Symposium '95. (February 6-8, 1995)

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-06

This is a collection of speeches and lectures delivered at the above-named symposium that took place in Tokyo. Three speakers from Japan, Germany, and the U.S. made remarks about the future energy systems and the role of hydrogen; the hydrogen energy development status and plans in Europe; and the role of hydrogen in meeting southern California's air quality goals, respectively. Technical lectures numbering 22 in total included the photocatalytic reactions - water splitting and environmental applications; realization and operation of SWB's (Solar-Wasserstof-Bayern GmBH) development assembling major industrial-scale components of solar hydrogen technology; hydrogen production by UT-3 (University of Tokyo-3) thermochemical water decomposition cycle; energy and environmental technology in Japan - the New Sunshine Program; and research and development plans for WE-NET (World Energy Network). In the poster session, there were 45 exhibitions, which included development on solid polymer electrolyte water electrolysis in Mitsubishi Heavy Industries, Ltd.; development of environmentally friendly technology for the production of hydrogen; and recent progress of hydrogen storage and transportation technologies in North America. (NEDO)

Hydrogen-enriched fuels

Energy Technology Data Exchange (ETDEWEB)

Roser, R. [NRG Technologies, Inc., Reno, NV (United States)

1998-08-01

NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

Safety, codes and standards for hydrogen installations. Metrics development and benchmarking

Energy Technology Data Exchange (ETDEWEB)

Harris, Aaron P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dedrick, Daniel E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Angela Christine [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); San Marchi, Christopher W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-04-01

Automakers and fuel providers have made public commitments to commercialize light duty fuel cell electric vehicles and fueling infrastructure in select US regions beginning in 2014. The development, implementation, and advancement of meaningful codes and standards is critical to enable the effective deployment of clean and efficient fuel cell and hydrogen solutions in the energy technology marketplace. Metrics pertaining to the development and implementation of safety knowledge, codes, and standards are important to communicate progress and inform future R&D investments. This document describes the development and benchmarking of metrics specific to the development of hydrogen specific codes relevant for hydrogen refueling stations. These metrics will be most useful as the hydrogen fuel market transitions from pre-commercial to early-commercial phases. The target regions in California will serve as benchmarking case studies to quantify the success of past investments in research and development supporting safety codes and standards R&D.

Photon-photon collisions

International Nuclear Information System (INIS)

Burke, D.L.

1982-10-01

Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved

Photon-photon collisions

International Nuclear Information System (INIS)

Haissinski, J.

1986-06-01