WorldWideScience

Sample records for neutral hydrogen absorption

  1. Galactic neutral hydrogen emission-absorption observations from Arecibo

    International Nuclear Information System (INIS)

    Dickey, J.M.; Salpeter, E.E.; Terzian, Y.

    1978-01-01

    We have observed the interstellar medium in the directions of 27 extragalactic sources at high and intermediate galactic latitudes (vertical-barb/sup ii/vertical-bar>5 0 ) at 21 cm wavelength with the upgraded Arecibo telescope (HPBW=3'.2, gainapprox.6 K Jy -1 ). The small beam greatly reduces the uncertainty in the derived on-source emission profile and increases confidence that it corresponds to the same material as the absorption spectrum. Each region has been observed for approximately 2 hours to tetect optical depths as low as 10 -2 in most cases. The data allow the derivation of optical depths, harmonic mean spin temperatures, and column densities for the neutral hydrogen as a function of velocity in the range -200 -1 (LSR) with resolution as fine as 0.25 km s -1 . Spin temperatures as high as 1000 K are evident with a significant fraction of the neutral hydrogen still hotter. The cooler material is distributed over all temperatures from 30 K to at least 800 K. At latitudes below vertical-barb/sup ii/vertical-bar 0 values for the harmonic mean temperature T/sub spin/ in the range 100 K to 300 K are most common.We have detected 66 separate absorption features, tentatively associated with neutral hydrogen clouds, with central temperatures ranging from 30 to 500 K. These features conform well to the relationship T/sub spin/=45(1-e/sup -tau/)/sup -0.5/ (K), over a broad range of values of the optical depth. The velocity distribution of these clouds shows a significant negative-velocity ''tail'' at high and intermediate latitudes. The mean square velocity of the clouds seems to depend on optical depth: v/sub rms/ is greater (approx.11 km s -1 ) for the optically thin clouds (tau -1 ). High-negative-velocity emission (v -1 ) has been detected in six directions; in two of these corresponding absorption features are evident, indicating cool neutral material

  2. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    International Nuclear Information System (INIS)

    Scime, Earl E.

    2016-01-01

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the H α line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support installation on their

  3. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Scime, Earl E. [West Virginia Univ., Morgantown, WV (United States)

    2016-09-23

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the Hα line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support

  4. Water absorption in neutralized Nafion membranes

    International Nuclear Information System (INIS)

    Rodmacq, B.; Roche, E.; Pineri, M.; Escoubez, M.; Duplessix, R.; Eisenberg, A.

    1979-01-01

    In this paper some results are reported about the interactions between water and Nafion neutralized with different cations. The energy of water absorption have been measured in the whole range of relative humidity pressures. Moessbauer spectra permit to get information about the change of environment of the iron atoms during the hydration. Small angle neutron and X ray scattering experiments have then been performed to define a possible phase segregation. From these results a model of clustering in the Nafion membranes is proposed. The neutralized Nafion samples have been obtained by soaking the acid samples in solutions containing the different salts

  5. Formation and infrared absorption of protonated naphthalenes (1-C10H9+ and 2-C10H9+) and their neutral counterparts in solid para-hydrogen.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Yu-Jong; Lee, Yuan-Pern

    2013-02-14

    Protonated naphthalene (C(10)H(9)(+)) and its neutral counterparts (hydronaphthyl radicals, C(10)H(9)) are important intermediates in the reactions of aromatic compounds and in understanding the unidentified infrared (IR) emissions from interstellar media. We report the IR spectra of 1-C(10)H(9)(+), 2-C(10)H(9)(+), 1-C(10)H(9), and 2-C(10)H(9) trapped in solid para-hydrogen (p-H(2)); the latter three are new. These species were produced upon electron bombardment of a mixture of naphthalene (C(10)H(8)) and p-H(2) during matrix deposition. The intensities of IR features of 1-C(10)H(9)(+) decreased after the matrix was maintained in darkness for 19 h, whereas those of 1-C(10)H(9) and 2-C(10)H(9) increased. Irradiation of this matrix sample with light at 365 nm diminished lines of 1-C(10)H(9)(+) and 2-C(10)H(9) and enhanced lines of 1-C(10)H(9) and 2-C(10)H(9)(+); the latter species was unstable and converted to 1-C(10)H(9)(+) in less than 30 min and 2-C(10)H(9) was converted to 1-C(10)H(9) at 365 nm. Observed wavenumbers and relative intensities of these species agree satisfactorily with the anharmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. Compared with spectra recorded previously with IR photodissociation of Ar-tagged C(10)H(9)(+) or IR multiphoton dissociation of C(10)H(9)(+), our method has the advantages of producing high-resolution IR spectra with a wide spectral coverage, true IR intensity and excellent ratio of signal to noise; both protonated species and their neutral counterparts are produced with little interference from other fragments. With these advantages, the IR spectra of 1-C(10)H(9)(+), 2-C(10)H(9)(+), 1-C(10)H(9), and 2-C(10)H(9) are here clearly characterized.

  6. Circumnebular neutral hydrogen in planetary nebulae

    International Nuclear Information System (INIS)

    Taylor, A.R.; Gussie, G.T.; Pottasch, S.R.

    1990-01-01

    Centimeter line observations of six compact planetary nebulae are reported. Circumnebular atomic hydrogen absorption has been observed in NGC 6790, NGC 6886, IC 418, IC 5117, and BD +30 deg 3639, while H I was not observed to a high upper limit in NGC 6741. Hydrogen was also detected in emission from BD +30 deg 3639. The expansion velocities of the circumnebular envelopes are similar to the expansion velocities observed for the ionized nebula. The optical depth of circumnebular H I appears to decrease with increasing linear radius of the ionized nebulae, indicating that these nebulae are ionization bounded and that the amount of atomic hydrogen decreases as young nebulas evolve. 28 refs

  7. LOCAL INTERSTELLAR NEUTRAL HYDROGEN SAMPLED IN SITU BY IBEX

    International Nuclear Information System (INIS)

    Saul, Lukas; Wurz, Peter; Rodriguez, Diego; Scheer, Jürgen; Möbius, Eberhard; Schwadron, Nathan; Kucharek, Harald; Leonard, Trevor; Bzowski, Maciej; Fuselier, Stephen; Crew, Geoff; McComas, Dave

    2012-01-01

    Hydrogen gas is the dominant component of the local interstellar medium. However, owing to ionization and interaction with the heliosphere, direct sampling of neutral hydrogen in the inner heliosphere is more difficult than sampling the local interstellar neutral helium, which penetrates deep into the heliosphere. In this paper, we report on the first detailed analysis of the direct sampling of neutral hydrogen from the local interstellar medium. We confirm that the arrival direction of hydrogen is offset from that of the local helium component. We further report the discovery of a variation of the penetrating hydrogen over the first two years of Interstellar Boundary Explorer observations. Observations are consistent with hydrogen experiencing an effective ratio of outward solar radiation pressure to inward gravitational force greater than unity (μ > 1); the temporal change observed in the local interstellar hydrogen flux can be explained with solar variability.

  8. Neutral hydrogen observations of binary galaxies

    International Nuclear Information System (INIS)

    Moorsel, G.A. van.

    1982-01-01

    The present investigation concerns a detailed neutral hydrogen study of a carefully selected sample of 16 double spiral galaxies with the Westerbork Synthesis Radio Telescope (WSRT). The observational data provide useful material for a number of questions concerning the dynamics of double galaxies, in particular the question of the mass distribution. In Chapter 2 the criteria used to select a sample of double galaxies for observation with the WSRT are discussed. Observing techniques and the reduction of the data using the GIPSY system are described in Chapter 3. Chapters 4 through 7 contain the observational results. In Chapter 8 the method of analysis is described. Masses for the individual galaxies derived from rotation curves are compared with the ''total'' masses estimated from the orbital motion. In this fashion a direct estimate of the amount of dark matter is obtained that avoids the use of mean M/L values. In Chapter 9 a mass estimator for groups is developed in a way analogous to the binary galaxy mass estimator described in Chapter 8. The question of selection effects and the bias of the mass estimator for the point mass model are discussed extensively in Chapter 10. The final results are discussed in Chapter 11. It is shown that the orbital mass exceeds the sum of the individual masses by a large factor for several pairs, indicating either that there is a large amount of dark matter or that something is amiss with the concept of a physical pair. (Auth.)

  9. Cosmological Evolution of the Universe Neutral Gas Mass Measured by Quasar Absorption Systems

    OpenAIRE

    Peroux, Celine; McMahon, Richard G.; Irwin, Mike; Storrie-Lombardi, Lisa J.

    2001-01-01

    The cosmological evolution of neutral hydrogen is an efficient way of tracing structure formation with redshift. It indicates the rate of evolution of gas into stars and hence the gas consumption and rate star formation history of the Universe. In measuring HI, quasar absorbers have proven to be an ideal tool and we use observations from a recent survey for high-redshift quasar absorption systems together with data gathered from the literature to measure the cosmological comoving mass density...

  10. The environmental dependence of neutral hydrogen in the gimic simulations

    CSIR Research Space (South Africa)

    Cunnama, D

    2014-01-01

    Full Text Available We use the Galaxies-Intergalactic Medium Interaction Calculation (GIMIC) cosmological hydrodynamic simulation at z = 0 to study the distribution and environmental dependence of neutral hydrogen (Hi) gas in the outskirts of simulated galaxies...

  11. ExoCube INMS with Neutral Hydrogen Mode

    Science.gov (United States)

    Jones, S.; Paschalidis, N.; Rodriguez, M.; Sittler, E. C., Jr.; Chornay, D. J.; Cameron, T.; Uribe, P.; Nanan, G.; Noto, J.; Waldrop, L.; Mierkiewicz, E. J.; Gardner, D.; Nossal, S. M.; Puig-Suari, J.; Bellardo, J.

    2015-12-01

    The ExoCube mission launched on Jan 31 2015 into a polar orbit to acquire global knowledge of in situ densities of neutral and ionized H, He, and O in the upper ionosphere and lower exosphere. The CubeSat platform is used in combination with incoherent scatter radar and optical ground stations distributed throughout the Americas. ExoCube seeks to obtain the first in situ measurement of neutral exospheric hydrogen and will measure in situ atomic oxygen for the first time in decades. The compact Ion and Neutral Mass Spectrometer (INMS) developed by GSFC uses the gated Time of Flight technique for in situ measurements of ions and neutrals (H, He, N, O, N2, O2) with M/dM of approximately 10. The compact sensor has a dual symmetric configuration with ion and neutral sensor heads. Neutral particles are ionized by electron impact using a thermionic emitter. In situ measurements of neutral hydrogen are notoriously difficult as historically the signal has been contaminated by hydrogen outgassing which persists even years after commissioning. In order to obtain neutral atmospheric hydrogen fluxes, either the atmospheric peak and outgassing peak must be well resolved, or the outgassing component subtracted off. The ExoCube INMS employs a separate mode, specifically for measuring neutral Hydrogen. The details of this mode and lessons learned will be presented as well as in flight instrument validation data for the neutral channel and preliminary flight ion spectra. At the time of abstract submission, the ExoCube spacecraft is currently undergoing attitude control maneuvers to orient INMS in the ram direction for science operations.

  12. Neutral Hydrogen in Local Group Dwarf Galaxies

    Science.gov (United States)

    Grcevich, Jana

    The gas content of the faintest and lowest mass dwarf galaxies provide means to study the evolution of these unique objects. The evolutionary histories of low mass dwarf galaxies are interesting in their own right, but may also provide insight into fundamental cosmological problems. These include the nature of dark matter, the disagreement between the number of observed Local Group dwarf galaxies and that predicted by lambda cold dark matter models, and the discrepancy between the observed census of baryonic matter in the Milky Way's environment and theoretical predictions. This thesis explores these questions by studying the neutral hydrogen (HI) component of dwarf galaxies. First, limits on the HI mass of the ultra-faint dwarfs are presented, and the HI content of all Local Group dwarf galaxies is examined from an environmental standpoint. We find that those Local Group dwarfs within 270 kpc of a massive host galaxy are deficient in HI as compared to those at larger galactocentric distances. Ram-pressure arguments are invoked, which suggest halo densities greater than 2-3 x 10-4 cm-3 out to distances of at least 70 kpc, values which are consistent with theoretical models and suggest the halo may harbor a large fraction of the host galaxy's baryons. We also find that accounting for the incompleteness of the dwarf galaxy count, known dwarf galaxies whose gas has been removed could have provided at most 2.1 x 108 M⊙ of HI gas to the Milky Way. Second, we examine the possibility of discovering unknown gas-rich ultra-faint galaxies in the Local Group using HI. The GALFA-HI Survey catalog is searched for compact, isolated HI clouds which are most similar to the expected HI characteristics of low mass dwarf galaxies. Fifty-one Local Group dwarf galaxy candidates are identified through column density, brightness temperature, and kinematic selection criteria, and their properties are explored. Third, we present hydrodynamic simulations of dwarf galaxies experiencing a

  13. Diagnostics for hot plasmas using hydrogen neutral beams

    International Nuclear Information System (INIS)

    Goldston, R.J.

    1982-12-01

    Beams of neutral hydrogen atoms have found a number of uses in the diagnosis of hot plasmas. In the most straightforward application, neutral beams have been used to determine plasma line density, based on simple attenuation measurements. This technique has been applied most intensively recently to the study of beam-injected mirror plasmas. Neutral beams have also now been used in a number of tokamaks to supply a local increase of the neutral atom target density for charge exchange. By directing a time-modulated neutral beam across the sight-line of a charge-exchange analyzer, and measuring the modulated neutral particle efflux from the plasma, local measurements of the ion energy distribution function can be made. If a modulated diagnostic neutral beam is directed across the sight-line of an ultra-violet spectrometer, one can also make measurements of the local densities and possibly velocity distributions of fully stripped impurities. The fast hydrogen neutrals charge exchange with fully stripped impurities in the plasma, leaving the impurities in excited hydrogen-like states. In their prompt radiative decay the impurity ions emit characteristic uv lines, which can be detected easily

  14. Novel xenon calibration scheme for two-photon absorption laser induced fluorescence of hydrogen

    International Nuclear Information System (INIS)

    Elliott, Drew; Scime, Earl; Short, Zachary

    2016-01-01

    Two photon absorption laser induced fluorescence (TALIF) measurements of neutral hydrogen and its isotopes are typically calibrated by performing TALIF measurements on krypton with the same diagnostic system and using the known ratio of the absorption cross sections [K. Niemi et al., J. Phys. D 34, 2330 (2001)]. Here we present the measurements of a new calibration method based on a ground state xenon scheme for which the fluorescent emission wavelength is nearly identical to that of hydrogen, thereby eliminating chromatic effects in the collection optics and simplifying detector calibration. We determine that the ratio of the TALIF cross sections of xenon and hydrogen is 0.024 ± 0.001.

  15. Dust clouds in Orion and the interstellar neutral hydrogen distribution

    International Nuclear Information System (INIS)

    Bystrova, N.V.

    1989-01-01

    According to published examples of the far IR observations in the Orion and its surroundings, several well defined dust clouds of different sizes and structure are present. For comparison of these clouds with the neutral hydrogen distribution on the area of approx. 1000 sq degs, the data from Pulkovo Sky Survey in the interstellar neutral Hydrogen Radio Line as well as special observations with the RATAN-600 telescope in 21 cm line were used. From the materials of Pulkovo HI Survey, the data were taken near the line emission at ten velocities between -21.8 and +25.6 km/s LSR for the structural component of the interstellar hydrogen emission. The results given concern mainly the Orion's Great Dust Cloud and the Lambda Orionis region where the information about the situation with the dust and interstellar hydrogen is very essential for interpretation

  16. A neutral hydrogen bipole associated with UW CMa

    International Nuclear Information System (INIS)

    Denby, B.; Taylor, K.N.R.

    1986-01-01

    During a recent study of features associated with early-type stars, a linearly extended, low-mass (180 Msolar masses) cloud of neutral hydrogen in the vicinity of UW CMa has been observed. The structure of this cloud and its velocity field suggest that it is indeed associated with UW CMa. Possible models for their relation are considered. (author)

  17. Complexes associated with silicon and hydrogen in the neutralization mechanism of active donors in hydrogenated GaAs: Si(n)

    Energy Technology Data Exchange (ETDEWEB)

    Chevallier, J.; Jalil, A.; Pesant, J.C.; Mostefaoui, R.; Pajot, B.; Murawala, P.; Azoulay, R.

    1987-08-01

    After hydrogen plasma exposure of a n type GaAs:Si crystal, we observe a decrease of the free carrier concentration and a hydrogen diffusion in the near surface region of the material. In bulk crystals, a good correlation has been established between the hydrogen penetration depth and the depth where the free carrier concentration recovers its bulk value. The decrease of the carrier concentration is accompanied by a significant increase of the electron mobility. This increase reveals a neutralization of the active donors and their transformation into electrically neutral complexes. A detailed infrared spectroscopy study on plasma exposed GaAs:Si epilayers shows a very sharp absorption line at 890 cm/sup -1/ on hydrogenated samples and 637 cm/sup -1/ on deuterated samples. These bands are totally absent in hydrogenated undoped GaAs. The isotopic shift frequency analysis indicates that the 890 cm/sup -1/ line could be associated with an arsenic-hydrogen bond where arsenic is supposed to sit as a first nearest neighbour of a silicon donor. Isochronal annealing experiments show a good correlation between the 890 cm/sup -1/ absorption band intensity and the neutralized silicon donor concentration. The neutralization would be due to the formation of (SiAs/sub 3/) As-H complexes, the extra electron of the silicon donor being trapped in order to participate to the As-H bond.

  18. Hydrolysis Batteries: Generating Electrical Energy during Hydrogen Absorption.

    Science.gov (United States)

    Xiao, Rui; Chen, Jun; Fu, Kai; Zheng, Xinyao; Wang, Teng; Zheng, Jie; Li, Xingguo

    2018-02-19

    The hydrolysis reaction of aluminum can be decoupled into a battery by pairing an Al foil with a Pd-capped yttrium dihydride (YH 2 -Pd) electrode. This hydrolysis battery generates a voltage around 0.45 V and leads to hydrogen absorption into the YH 2 layer. This represents a new hydrogen absorption mechanism featuring electrical energy generation during hydrogen absorption. The hydrolysis battery converts 8-15 % of the thermal energy of the hydrolysis reaction into usable electrical energy, leading to much higher energy efficiency compared to that of direct hydrolysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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.)

  20. A large neutral fraction of cosmic hydrogen a billion years after the Big Bang.

    Science.gov (United States)

    Wyithe, J Stuart B; Loeb, Abraham

    2004-02-26

    The fraction of ionized hydrogen left over from the Big Bang provides evidence for the time of formation of the first stars and quasar black holes in the early Universe; such objects provide the high-energy photons necessary to ionize hydrogen. Spectra of the two most distant known quasars show nearly complete absorption of photons with wavelengths shorter than the Lyman alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift of z approximately 6.3, about one billion years after the Big Bang. Here we show that the IGM surrounding these quasars had a neutral hydrogen fraction of tens of per cent before the quasar activity started, much higher than the previous lower limits of approximately 0.1 per cent. Our results, when combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination therefore suggest the presence of a second peak in the mean ionization history of the Universe.

  1. Depolarizing collisions with hydrogen: Neutral and singly ionized alkaline earths

    Energy Technology Data Exchange (ETDEWEB)

    Manso Sainz, Rafael; Ramos, Andrés Asensio; Bueno, Javier Trujillo [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Roncero, Octavio; Sanz-Sanz, Cristina [Instituto de Física Fundamental (IFF-CSIC), CSIC, Serrano 123, E-28006 Madrid (Spain); Aguado, Alfredo, E-mail: octavio.roncero@csic.es [Departamento de Química Física, Unidad Asociada UAM-CSIC, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, E-28049 Madrid (Spain)

    2014-06-20

    Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H°. We compute ab initio potential curves of the atom-H° system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T ≤ 10,000 K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.

  2. Effects of Pollutants and Microorganisms on the Absorption of Electrolytic Hydrogen in Iron

    National Research Council Canada - National Science Library

    Pickering, Howard

    1998-01-01

    ...) develop effective inhibitors for reducing hydrogen absorption. Thiosulfate in acidic solutions increases the hydrogen absorption into iron order of magnitude at 10mM while having little effect on the hydrogen evolution reaction (HER) kinetics...

  3. Kinetics of Hydrogen Absorption and Desorption in Titanium

    Directory of Open Access Journals (Sweden)

    Suwarno Suwarno

    2017-10-01

    Full Text Available Titanium is reactive toward hydrogen forming metal hydride which has a potential application in      energy storage and conversion. Titanium hydride has been widely studied for hydrogen storage, thermal storage, and battery electrodes applications. A special interest is using titanium for hydrogen production in a hydrogen sorption-enhanced steam reforming of natural gas. In the present work, non-isothermal dehydrogenation kinetics of titanium hydride and kinetics of hydrogenation in gaseous flow at isothermal conditions were investigated. The hydrogen desorption was studied using temperature desorption spectroscopy (TDS while the hydrogen absorption and desorption in gaseous flow were studied by temperature programmed desorption (TPD. The present work showed that the path of dehydrogenation of the TiH2 is d®b®a hydride phase with possible overlapping steps occurred. The fast hydrogen desorption rate observed at the TDS main peak temperature were correlated with the fast transformation of the d-TiH1.41 to b-TiH0.59. In the gaseous flow, hydrogen absorption and desorption were related to the transformation of b-TiH0.59 Û d-TiH1.41 with 2 wt.% hydrogen reversible content. Copyright © 2017 BCREC Group. All rights reserved Received: 21st November 2016; Revised: 20th March 2017; Accepted: 9th April 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Suwarno, S., Yartys, V.A. (2017. Kinetics of Hydrogen Absorption and Desorption in Titanium. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3: 312-317  (doi:10.9767/bcrec.12.3.810.312-317

  4. Electron-impact dissociation of molecular hydrogen into neutral fragments

    Science.gov (United States)

    Scarlett, Liam H.; Tapley, Jonathan K.; Fursa, Dmitry V.; Zammit, Mark C.; Savage, Jeremy S.; Bray, Igor

    2018-02-01

    We present convergent close-coupling calculations of electron-impact dissociation of the ground state of molecular hydrogen into neutral fragments over the range of impact energies from 6 to 300 eV. The calculations account for dissociative excitation, excitation radiative decay dissociation, and predissociation through all bound electronic triplet states, and singlet states up to the D' 1 Π u state. An estimate is given for the contribution from the remaining bound electronic singlet states. Our results are in agreement with the recommended data of Yoon et al. [J. Phys. Chem. Ref. Data 37, 913 (2008)] in the low (6-12 eV) and high (60-70 eV) energy regions, but somewhat lower at the intermediate energies.

  5. Interstellar Matters: Neutral Hydrogen and the Galactic Magnetic Field

    Science.gov (United States)

    Verschuur, Gerrit; Schmelz, Joan T.; Asgari-Targhi asgari-Targhi, M.

    2018-01-01

    The physics of the interstellar medium was revolutionized by the observations of the Galactic Arecibo L-Band Feed Array (GALFA) HI survey done at the Arecibo Observatory. The high-resolution, high-sensitivity, high-dynamic- range images show complex, tangled, extended filaments, and reveal that the fabric of the neutral interstellar medium is deeply tied to the structure of the ambient magnetic field. This discovery prompts an obvious question – how exactly is the interstellar {\\it neutral} hydrogen being affected by the galactic magnetic field? We look into this question by examining a set of GALFA-HI data in great detail. We have chosen a long, straight filament in the southern galactic sky. This structure is both close by and isolated in velocity space. Gaussian analysis of profiles both along and across the filament reveal internal structure – braided strands that can be traced through the simplest part, but become tangled in more complex segments. These braids do not resemble in any way the old spherical HI clouds and rudimentary pressure balance models that were used to explain the pre-GALFA- HI interstellar medium. It is clear that these structures are created, constrained, and dominated by magnetic fields. Like many subfields of astronomy before it, e.g., physics of the solar coronal, extragalactic radio jets, and pulsar environment, scientists are confronted with observations that simply cannot be explained by simple hydrodynamics and are forced to consider magneto-hydrodynamics.

  6. RECTIFIED ABSORPTION METHOD FOR THE SEPARATION OF HYDROGEN ISOTOPES

    Science.gov (United States)

    Hunt, C.D.; Hanson, D.N.

    1961-10-17

    A method is described for separating and recovering heavy hydrogen isotopes from gaseous mixtures by multiple stage cyclic absorption and rectification from an approximate solvent. In particular, it is useful for recovering such isoteoes from ammonia feedstock streams containing nitrogen solvent. Modifications of the process ranging from isobaric to isothermal are provided. Certain impurities are tolerated, giving advantages over conventional fractional distillation processes. (AEC)

  7. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  8. Measurement of He neutral temperature in detached plasmas using laser absorption spectroscopy

    Science.gov (United States)

    Aramaki, M.; Tsujihara, T.; Kajita, S.; Tanaka, H.; Ohno, N.

    2018-01-01

    The reduction of the heat load onto plasma-facing components by plasma detachment is an inevitable scheme in future nuclear fusion reactors. Since the control of the plasma and neutral temperatures is a key issue to the detached plasma generation, we have developed a laser absorption spectroscopy system for the metastable helium temperature measurements and used together with a previously developed laser Thomson scattering system for the electron temperature and density measurements. The thermal relaxation process between the neutral and the electron in the detached plasma generated in the linear plasma device, NAGDIS-II was studied. It is shown that the electron temperature gets close to the neutral temperature by increasing the electron density. On the other hand, the pressure dependence of electron and neutral temperatures shows the cooling effect by the neutrals. The possibility of the plasma fluctuation measurement using the fluctuation in the absorption signal is also shown.

  9. GLOBAL PROPERTIES OF NEUTRAL HYDROGEN IN COMPACT GROUPS

    International Nuclear Information System (INIS)

    Walker, Lisa May; Johnson, Kelsey E.; Gallagher, Sarah C.; Privon, George C.; Kepley, Amanda A.; Whelan, David G.; Desjardins, Tyler D.; Zabludoff, Ann I.

    2016-01-01

    Compact groups of galaxies provide a unique environment to study the evolution of galaxies amid frequent gravitational encounters. These nearby groups have conditions similar to those in the earlier universe when galaxies were assembled and give us the opportunity to witness hierarchical formation in progress. To understand how the compact group environment affects galaxy evolution, we examine the gas and dust in these groups. We present new single-dish GBT neutral hydrogen (H i) observations of 30 compact groups and define a new way to quantify the group H i content as the H i-to-stellar mass ratio of the group as a whole. We compare the H i content with mid-IR indicators of star formation and optical [g − r] color to search for correlations between group gas content and star formation activity of individual group members. Quiescent galaxies tend to live in H i-poor groups, and galaxies with active star formation are more commonly found in H i-rich groups. Intriguingly, we also find “rogue” galaxies whose star formation does not correlate with group H i content. In particular, we identify three galaxies (NGC 2968 in RSCG 34, KUG 1131+202A in RSCG 42, and NGC 4613 in RSCG 64) whose mid-IR activity is discrepant with the H i. We speculate that this mismatch between mid-IR activity and H i content is a consequence of strong interactions in this environment that can strip H i from galaxies and abruptly affect star formation. Ultimately, characterizing how and on what timescales the gas is processed in compact groups will help us understand the interstellar medium in complex, dense environments similar to the earlier universe

  10. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    Science.gov (United States)

    Nicovich, J. M.; Wine, P. H.

    1988-01-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  11. The kinetics of Cr layer coated on TiNi films for hydrogen absorption

    Indian Academy of Sciences (India)

    pressure by thermal evaporation on the glass substrate at room temperature. A layer of. Cr of thickness 100 Å was coated on the TiNi thin films. The changing rate of hydrogen absorption increases after Cr layer coating because Cr enhances the catalytic properties of hydrogen absorption in thin films. The rate of hydrogen ...

  12. Pd-Au Electrocatalysts for Hydrogen Evolution Reaction at Neutral pH

    Directory of Open Access Journals (Sweden)

    Elitsa Chorbadzhiyska

    2014-01-01

    Full Text Available Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts, produced from electrolyte with equal Pd and Au content.

  13. Pd-Au Electrocatalysts for Hydrogen Evolution Reaction at Neutral pH

    OpenAIRE

    Elitsa Chorbadzhiyska; Mario Mitov; Georgi Hristov; Nina Dimcheva; Lori Nalbandian; Antigoni Evdou; Yolina Hubenova

    2014-01-01

    Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts...

  14. The Absorption-Desorption of Hydrogen by 1.5 g Depleted Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sunmi; Paek, Seungwoo; Lee, Minsoo; Kim, Si-Hyung; Kim, Kwang-Rag; Ahn, Do-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Sohn, Soon Hwan; Song, Kyu Min [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    The form of metal tritides is one of the most popular methods for the storage of hydrogen isotopes. Particularly when metal is in a powder form, the storage capacity of hydrogen isotopes become the maximum value. Here, a 1.5g depleted uranium metal was decrepitated into a powder upon an absorption and desorption of hydrogen gas. The conditions for an activation, absorption-desorption of the hydrogen were defined.

  15. The Absorption-Desorption of Hydrogen by 1.5 g Depleted Uranium

    International Nuclear Information System (INIS)

    Kim, Sunmi; Paek, Seungwoo; Lee, Minsoo; Kim, Si-Hyung; Kim, Kwang-Rag; Ahn, Do-Hee; Sohn, Soon Hwan; Song, Kyu Min

    2008-01-01

    The form of metal tritides is one of the most popular methods for the storage of hydrogen isotopes. Particularly when metal is in a powder form, the storage capacity of hydrogen isotopes become the maximum value. Here, a 1.5g depleted uranium metal was decrepitated into a powder upon an absorption and desorption of hydrogen gas. The conditions for an activation, absorption-desorption of the hydrogen were defined

  16. Studies of hydrogen incorporation in hydrogenated amorphous carbon films by infrared absorption spectroscopy

    International Nuclear Information System (INIS)

    Alameh, R.; Bounouh, Y.; Sadki, A.; Naud, C.; Theye, M.L.

    1997-01-01

    Author.Hydrogenated amorphous carbon (a-C:H) films presently attract considerable interest because of their potential applications in the domain of multifunctional coatings: transparent in the infrared, very hard, chemically inert, etc...This material is rather complex since it contains C atoms in both sp 3 (diamond) and sp 2 (graphite) electronic configurations, as well as a large concentration of H atoms. Its properties are strongly dependent on the deposition conditions which determine the film microstructure, i.e. the relative proportions of sp 3 and sp 2 C sites, their connection in the network and the hydrogen bonding modes. It has been suggested that the sp 2 C sites tend to cluster into unsaturated chains ans rings, which are then embedded in the sp 3 C sites m atrix . Hydrogen incorporation plays a crucial role in this intrinsic microheterogeneity, which determines the electronic properties, and especially the gap value, of a-C:H. We here present and discuss the results of Fourrier transform infrared absorption spectroscopy measurements performed on a-C:H films prepared under different conditions and submitted to controlled annealing cycles, which exhibit quite different optical gap values (from 1 to 2.5 eV). We carefully analyze the absorption bands detected in the 400-7500 cm -1 spectral range in terms of the vibration modes of C-H and C-C bonds in different local environments and we interpret the results in relation with the film microstructure and optical properties. Special attention is also paid to the absorption background and to the variations of the whole absorption spectra with measurement temperature

  17. Hydrogen atom temperature measured with wavelength-modulated laser absorption spectroscopy in large scale filament arc negative hydrogen ion source

    International Nuclear Information System (INIS)

    Nakano, H.; Goto, M.; Tsumori, K.; Kisaki, M.; Ikeda, K.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Nishiyama, S.; Sasaki, K.

    2015-01-01

    The velocity distribution function of hydrogen atoms is one of the useful parameters to understand particle dynamics from negative hydrogen production to extraction in a negative hydrogen ion source. Hydrogen atom temperature is one of the indicators of the velocity distribution function. To find a feasibility of hydrogen atom temperature measurement in large scale filament arc negative hydrogen ion source for fusion, a model calculation of wavelength-modulated laser absorption spectroscopy of the hydrogen Balmer alpha line was performed. By utilizing a wide range tunable diode laser, we successfully obtained the hydrogen atom temperature of ∼3000 K in the vicinity of the plasma grid electrode. The hydrogen atom temperature increases as well as the arc power, and becomes constant after decreasing with the filling of hydrogen gas pressure

  18. Preparation and Hydrogen Absorption/Desorption Properties of Palladium/kieselguhr Composite

    International Nuclear Information System (INIS)

    Chen Wei; Li Shenlan; Luo Gang; Han Xingbo; Chen Demin; Liu Shi; Yang Ke

    2010-01-01

    A palladium-kieselguhr composite (Pd/K) was prepared by PdCl 2 dipping-reducing method. Distribution of palladium and hydrogen absorption/desorption properties including pressure-composition isotherms (p-C-T curves), absorption kinetics, thermodynamic parameters and absorption/desorption cycling properties of the Pd/K composite were investigated. Compared to pure palladium, hydrogen uptake capacity of the Pd/K composite is decreased, the absorption plateau pressure and plateau slope increase slightly, but the absorption rate is doubled. After 2 000 cycles of hydrogen absorption/desorption, hydrogen uptake capacity and absorption kinetics of the Pd/K composite keep stable with a pulverization rate of 3.6%(mass). (authors)

  19. Hydrogen absorption kinetics of niobium with an ion-plated nickel overlayer

    International Nuclear Information System (INIS)

    Nakamura, K.

    1981-01-01

    The hydrogen absorption rate for nickel-ion-plated niobium was measured as a function of hydrogen pressure and temperature. The observed absorption curves of c(mean)/csub(e) against time (c(mean) and csub(e) are the mean and equilibrium hydrogen concentrations respectively) exhibited a marked hydrogen pressure dependence below 628 K but this was less marked above 723 K. The results were analysed on the basis of the proposed model that the rate-determining step is the hydrogen permeation through the nickel overlayer and that the permeation is driven by the hydrogen activity difference between the two interfaces, namely the H 2 -Ni and Ni-Nb interfaces. The marked pressure dependence can be attributed to the fact that the hydrogen activity coefficient in nickel is constant and that in niobium it varies markedly with concentration, i.e. with hydrogen pressure and temperature. It was also found that the change in the nickel overlayer structure caused by the dilatation of bulk niobium during hydrogen absorption enhances the hydrogen absorption rates. The temperature dependence of the hydrogen absorption rate is also discussed in comparison with that for tantalum with a vacuum-deposited nickel overlayer. (Auth.)

  20. A neutral hydrogen study of the integral-sign galaxy MCG 12-7-28

    International Nuclear Information System (INIS)

    Bottinelli, L.; Gouguenheim, L.

    1975-01-01

    The 'integral-sign' galaxy MCG 12-7-28 has been studied in the 21-cm line of neutral hydrogen with the Nancay radio telescope. Its integral properties are consistent with the following results: The galaxy has an Sb or Sbc type, it is located at a distance of about 18 Mpc and it is seen edge-on. (orig.) [de

  1. Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of cold negative ions

    Science.gov (United States)

    Hershcovitch, A.

    1984-02-13

    A process for selectively neutralizing H/sup -/ ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H/sup -/ ions that are

  2. Negative hydrogen ion sources for neutral beam injectors

    International Nuclear Information System (INIS)

    Prelec, K.

    1977-01-01

    Negative ion sources offer an attractive alternative in the design of high energy neutral beam injectors. The requirements call for a single source unit capable of yielding H - or D - beam currents of up to 10 A, operating with pulses of 1 s duration or longer, with gas and power efficiencies comparable to or better than achievable with double electron capture systems. H - beam currents of up to 1 A have already been achieved in pulses of 10 ms; gas and power efficiencies were, however, lower than required. In order to increase the H - yield, extend the pulse length and improve gas and power efficiencies fundamental processes in the source plasma and on cesium covered electrode surfaces have to be analyzed; these processes will be briefly reviewed and scaling rules established. Based on these considerations as well as on results obtained with 1 A source models a larger model was designed and constructed, having a 7.5 cm long cathode with forced cooling. Results of initial tests will be presented and possible scaling up to 10 A units discussed

  3. Extended x-ray absorption fine structure: Studies of zinc-neutralized sulfonated polystyrene ionomers

    International Nuclear Information System (INIS)

    Ding, Y.S.; Yarusso, D.J.; Pan, H.K.D.; Cooper, S.L.

    1984-01-01

    Extended x-ray absorption fine structure (EXAFS) measurements were performed on a series of zinc-neutralized sulfonated polystyrene ionomers and the local structure around the zinc atom was determined. An interference effect in the EXAFS signal between sulfur and oxygen atoms was found to be significant in these materials. A model for the local structure in the zinc-neutralized sulfonated polystyrene ionomers is proposed which suggests a highly ordered tetrahedral coordination of oxygen around the zinc atoms at a distance of 1.97 +- 0.02 A. In addition there are four sulfur atoms and four oxygen atoms at a distance of 3.15 +- 0.05 A. No zinc-zinc coordination within 5 A was detected in this study

  4. Analytical model of neutral gas shielding for hydrogen pellet ablation

    Energy Technology Data Exchange (ETDEWEB)

    Kuteev, Boris V.; Tsendin, Lev D. [State Technical Univ., St. Petersburg (Russian Federation)

    2001-11-01

    A kinetic gasdynamic scaling for hydrogen pellet ablation is obtained in terms of a neural gas shielding model using both numerical and analytical approaches. The scaling on plasma and pellet parameters proposed in the monoenergy approximation by Milora and Foster dR{sub pe}/dt{approx}S{sub n}{sup 2/3}R{sub p}{sup -2/3}q{sub eo}{sup 1/3}m{sub i}{sup -1/3} is confirmed. Here R{sub p} is the pellet radius, S{sub n} is the optical thickness of a cloud, q{sub eo} is the electron energy flux density and m{sub i} is the molecular mass. Only the numeral factor is approximately two times less than that for the monoenergy approach. Due to this effect, the pellet ablation rates, which were obtained by Kuteev on the basis of the Milora scaling, should be reduced by a factor of 1.7. Such a modification provides a reasonable agreement (even at high plasma parameters) between the two-dimensional kinetic model and the one-dimensional monoenergy approximation validated in contemporary tokamak experiments. As the could (in the kinetic approximation) is significantly thicker than that for the monoenergy case as well as the velocities of the gas flow are much slower, the relative effect of plasma and magnetic shielding on the ablation rate is strongly reduced. (author)

  5. Absorption spectrum of neutral phosphorus (P I) in the range 7700-8256 A

    International Nuclear Information System (INIS)

    Deng Lunhua; Li Chuanliang; Zhang Junli; Yang Xiaohua; Chen Yangqin

    2010-01-01

    The absorption spectrum of neutral phosphorus was recorded in the range 7700-8256 A using optical heterodyne magnetic rotation concentration modulation spectroscopy with a tunable Ti:sapphire laser as the light source. Phosphorus atoms were excited by discharging the mixed gases of phosphorus vapor and neon gas. The phosphorus vapor was prepared by heating white phosphorus chips placed on a cylindrical copper electrode during discharge. In total, 234 lines of P I were observed, of which 127 were assigned. The transition frequencies were obtained with an uncertainty of 0.007 cm -1 . Empirical line intensities were provided covering four orders of magnitude.

  6. Absorption spectrum of neutral phosphorus (P I) in the range 7700-8256 Å

    Science.gov (United States)

    Deng, Lunhua; Li, Chuanliang; Zhang, Junli; Yang, Xiaohua; Chen, Yangqin

    2010-12-01

    The absorption spectrum of neutral phosphorus was recorded in the range 7700-8256 Å using optical heterodyne magnetic rotation concentration modulation spectroscopy with a tunable Ti:sapphire laser as the light source. Phosphorus atoms were excited by discharging the mixed gases of phosphorus vapor and neon gas. The phosphorus vapor was prepared by heating white phosphorus chips placed on a cylindrical copper electrode during discharge. In total, 234 lines of P I were observed, of which 127 were assigned. The transition frequencies were obtained with an uncertainty of 0.007 cm-1. Empirical line intensities were provided covering four orders of magnitude.

  7. Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

    Science.gov (United States)

    Welty, Daniel E.

    1990-01-01

    Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties.

  8. Direct measurement of interstellar extinction toward young stars using atomic hydrogen Lyα absorption

    Energy Technology Data Exchange (ETDEWEB)

    McJunkin, Matthew; France, Kevin; Brown, Alexander [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Schneider, P. C. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Hillenbrand, Lynne [California Institute of Technology, Department of Astrophysics, MC105-24, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Schindhelm, Eric [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Edwards, Suzan, E-mail: matthew.mcjunkin@colorado.edu [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States)

    2014-01-10

    Interstellar reddening corrections are necessary to reconstruct the intrinsic spectral energy distributions (SEDs) of accreting protostellar systems. The stellar SED determines the heating and chemical processes that can occur in circumstellar disks. Measurement of neutral hydrogen absorption against broad Lyα emission profiles in young stars can be used to obtain the total H I column density (N(H I)) along the line of sight. We measure N(H I) with new and archival ultraviolet observations from the Hubble Space Telescope (HST) of 31 classical T Tauri and Herbig Ae/Be stars. The H I column densities range from log{sub 10}(N(H I)) ≈19.6-21.1, with corresponding visual extinctions of A{sub V} =0.02-0.72 mag, assuming an R{sub V} of 3.1. We find that the majority of the H I absorption along the line of sight likely comes from interstellar rather than circumstellar material. Extinctions derived from new HST blue-optical spectral analyses, previous IR and optical measurements, and new X-ray column densities on average overestimate the interstellar extinction toward young stars compared to the N(H I) values by ∼0.6 mag. We discuss possible explanations for this discrepancy in the context of a protoplanetary disk geometry.

  9. Hydrogen absorption/desorption characteristics of room temperature ...

    Indian Academy of Sciences (India)

    Administrator

    . cSolid State Chemistry Section, Babha Atomic Research Centre, Mumbai 400 085, India ... As per the. USDOE's referred technical target, for the success of hydrogen economy, it is essential to develop a hydrogen storage material which can ...

  10. Revision of Collisional-Radiative Models and Neutral-Transport Code for Hydrogen and Helium Species

    International Nuclear Information System (INIS)

    Sawada, Keiji; Goto, Motoshi

    2013-01-01

    We have been developing collisional-radiative models and a neutral-transport code for hydrogen and helium species, which are used to investigate fusion plasmas. Collisional-radiative models of atomic hydrogen and helium have been applied to a helium-hydrogen RF plasma at Shinshu University, Japan, to test whether these models reproduce the observed emission intensities. The electron temperature and density are determined from visible emission line intensities of helium atom considering photoexcitation from the ground state to singlet P states, which is accompanied by radiation trapping. From the observed hydrogen Balmer γ line intensity, which is hardly affected by photoexcitation, the atomic hydrogen density is determined using a hydrogen collisional-radiative model that ignores photoexcitation. The atomic hydrogen temperature, which reproduces Balmer α and β line intensities, is determined using an iterative hydrogen atom collisional-radiative model that calculates photoexcitation rates. R-Matrix cross sections for n≤5 are used in the model. The hope is hoped that precise cross sections for higher-lying levels will be produced to determine the atomic density in fusion plasmas

  11. Simultaneous Hydrogen Generation and Waste Acid Neutralization in a Reverse Electrodialysis System

    KAUST Repository

    Hatzell, Marta C.

    2014-09-02

    Waste acid streams produced at industrial sites are often co-located with large sources of waste heat (e.g., industrial exhaust gases, cooling water, and heated equipment). Reverse electrodialysis (RED) systems can be used to generate electrical power and hydrogen gas using waste heat-derived solutions, but high electrode overpotentials limit system performance. We show here that an ammonium bicarbonate (AmB) RED system can achieve simultaneous waste acid neutralization and in situ hydrogen production, while capturing energy from excess waste heat. The rate of acid neutralization was dependent on stack flow rate and increased 50× (from 0.06 ± 0.04 to 3.0 ± 0.32 pH units min -1 m-2 membrane), as the flow rate increased 6× (from 100 to 600 mL min-1). Acid neutralization primarily took place due to ammonium electromigration (37 ± 4%) and proton diffusion (60 ± 5%). The use of a synthetic waste acid stream as a catholyte (pH ≈ 2) also increased hydrogen production rates by 65% (from 5.3 ± 0.5 to 8.7 ± 0.1 m3 H2 m-3 catholyte day -1) compared to an AmB electrolyte (pH ≈ 8.5). These findings highlight the potential use of dissimilar electrolytes (e.g., basic anolyte and acidic catholyte) for enhanced power and hydrogen production in RED stacks. © 2014 American Chemical Society.

  12. Functional differential equations of neutral type with integrable weak singularity: hydrogen thermal desorption model

    Science.gov (United States)

    Zaika, Yury V.; Kostikova, Ekaterina K.

    2017-11-01

    One of the technological challenges for hydrogen materials science (including the ITER project) is the currently active search for structural materials with various potential applications that will have predetermined limits of hydrogen permeability. One of the experimental methods is thermal desorption spectrometry (TDS). A hydrogen-saturated sample is degassed under vacuum and monotone heating. The desorption flux is measured by mass spectrometer to determine the character of interactions of hydrogen isotopes with the solid. We are interested in such transfer parameters as the coefficients of diffusion, dissolution, desorption. The paper presents a thermal desorption functional differential equations of neutral type with integrable weak singularity and a numerical method for TDS spectrum simulation, where only integration of a nonlinear system of low order ordinary differential equations (ODE) is required. This work is supported by the Russian Foundation for Basic Research (project 15-01-00744).

  13. The effect of organic molecules adsorption on hydrogen absorption in relation to the hydrogen evolution reaction

    Directory of Open Access Journals (Sweden)

    LJILJANA VRACAR

    2001-12-01

    Full Text Available The competitive adsorption of organic molecules (2,7-naphthalenedisulfonic acid and adsorbed H is of interest in relation to its influence on H absorption into a Pd-Ni electrodeposited alloy. The experimental results, in acid solution, show an enhancement of the coverage of the electrode surface with adosrbed H due to the competitive adsorption of organic molecules that interfere with H atoms, through lateral attractive interactions between the adsorbed species and communal electronic effects, leading supposedly to a decreased probability of H entry into the alloy. Chemisorbed H is, on the other hand, an intermediate in the HER, so the enhancement of the electrode coverage in the presence of co-adsorbed organic molecules promotes the hydrogen evolution reaction.

  14. Free-free absorption of infrared radiation in collisions of electrons with neutral rare-gas atoms

    Science.gov (United States)

    Stallcop, J. R.

    1974-01-01

    A relationship between the inverse bremsstrahlung absorption cross section and the electron neutral momentum transfer cross section has been utilized to determine the infrared free-free continuum absorption coefficient for the negative ions of helium, neon, argon, krypton, and xenon. The values of the momentum transfer cross section for this calculation have been obtained from experimental measurements. Analytical expressions for the absorption coefficient have also been developed. From the results of this calculation, it is possible to determine the absorption coefficient per unit electron density per neutral atom for temperatures in the range from 2500 to 25,000 K. The results are compared with those from tabulations of previous calculations and those computed from theoretical values of the phase shifts for the elastic scattering of electrons by neutral atoms.

  15. Analytical Absorption Cross-Section for Photon by a Hydrogen 2s Atom

    International Nuclear Information System (INIS)

    Ndinya, Boniface Otieno; Okeyo, Stephen Onyango

    2011-01-01

    We calculate the absorption cross-section for photon by a hydrogen 2s atom using the quantum-classical approximation for the total photo cross-section of many electron atoms. With the application of the first-order term of the Baker-Hausdorf expansion, the absorption cross-section for the hydrogen 2s atom decreases to a minimum, the Cooper pair minimum, at low photon energy. Such a minimum is absent in the exact absorption cross-section for photon by a hydrogen 2s atom. We have extended the calculation for the absorption cross-section of the hydrogen 2s atom using the quantum-classical approximation for the total photo cross-section of many electron to include the second-order term of the Baker-Hausdorf expansion and observed a great reduction in the dip associated with the Cooper pair minimum at the zero crossing. (atomic and molecular physics)

  16. Corrosion and hydrogen absorption of commercially pure zirconium in acid fluoride solutions

    International Nuclear Information System (INIS)

    Yokoyama, Ken’ichi; Yamada, Daisuke; Sakai, Jun’ichi

    2013-01-01

    Highlights: •Zirconium corrodes and absorbs hydrogen in acid fluoride solutions. •Hydrogen thermal desorption is observed at 300–700 °C. •The resistance to hydrogen absorption of zirconium is higher than that of titanium. -- Abstract: The corrosion and hydrogen absorption of commercially pure zirconium have been investigated in acidulated phosphate fluoride (APF) solutions. Upon immersion in 2.0% APF solution of pH 5.0 at 25 °C, a granular corrosion product (Na 3 ZrF 7 ) deposits over the entire side surface of the specimen, thereby inhibiting further corrosion. In 0.2% APF solution, marked corrosion is observed from the early stage of immersion; no deposition of the corrosion product is observed by scanning electron microscopy. A substantial amount of hydrogen absorption is confirmed in both APF solutions by hydrogen thermal desorption analysis. The amount of absorbed hydrogen of the specimen immersed in the 2.0% APF solution is smaller than that in the 0.2% APF solution in the early stage of immersion. The hydrogen absorption behavior is not always consistent with the corrosion behavior. Hydrogen thermal desorption occurs in the temperature range of 300–700 °C for the specimen without the corrosion product. Under the same immersion conditions, the amount of absorbed hydrogen in commercially pure zirconium is smaller than that in commercially pure titanium as reported previously. The present results suggest that commercially pure zirconium, compared with commercially pure titanium, is highly resistant to hydrogen absorption, although corrosion occurs in fluoride solutions

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

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  18. Thermodynamic and kinetics models of hydrogen absorption bound to phase transformations; Modelisation thermodynamique et cinetiques d'absorption d'hydrogene associees aux transformations de phase

    Energy Technology Data Exchange (ETDEWEB)

    Gondor, G.; Lexcellent, Ch. [Institut FEMTO-ST, Lab. de Mecanique Appliquee R. Chaleat (LMARC), 25 - Besancon (France)

    2007-07-01

    In order to design hydrogen gaseous pressure tanks, the absorption (desorption) of hydrogen has to be described and modelled. The equilibrium state can be described by the 'H{sub 2} gas pressure - H{sub 2} composition in the intermetallic compounds - isotherms' (PCI) curves. Several models of PCI curves already exist. At the beginning of the absorption, the hydrogen atoms and the intermetallic compounds form a solid solution ({alpha} phase). When the hydrogen concentration increases, a phase transformation appears changing the {alpha} solid solution into an hydride ({beta} phase) (solid solution + H{sub 2} {r_reversible} hydride). When all the solid solution has been transformed into hydride, the absorbed hydrogen atoms are in {beta} phase. A new thermodynamic model has been developed in order to take into account this transition phase. The equilibrium state is then given by a relation between the H{sub 2} gas pressure and the H{sub 2} concentration in the intermetallic compound for a fixed external temperature. Two kinetics models have been developed too; at first has been considered that the kinetics depend only of the entire concentration in the intermetallic compound and of the difference between the applied pressure and the equilibrium pressure. Then, has been considered that the hydrogen concentration changes in the metallic matrix. In this last case, for each hydrogenation process, the absorption velocity is calculated to determine the slowest local process which regulates the local evolution of the hydrogen concentration. These two models are based on the preceding thermodynamic model of the PCI curves. (O.M.)

  19. Neutralized solar wind ahead of the Earth's magnetopause as contribution to non-thermal exospheric hydrogen

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2018-03-01

    Full Text Available In a most recent paper by Qin and Waldrop (2016, it had been found that the scale height of hydrogen in the upper exosphere of the Earth, especially during solar minimum conditions, appears to be surprisingly large. This indicates that during minimum conditions when exobasic temperatures should be small, large exospheric H-scale heights predominate. They thus seem to indicate the presence of a non-thermal hydrogen component in the upper exosphere. In the following parts of the paper we shall investigate what fraction of such expected hot hydrogen atoms could have their origin from protons of the shocked solar wind ahead of the magnetopause converted into energetic neutral atoms (ENAs via charge-exchange processes with normal atmospheric, i.e., exospheric hydrogen atoms that in the first step evaporate from the exobase into the magnetosheath plasma region. We shall show that, dependent on the sunward location of the magnetopause, the density of these types of non-thermal hydrogen atoms (H-ENAs becomes progressively comparable with the density of exobasic hydrogen with increasing altitude. At low exobasic heights, however, their contribution is negligible. At the end of this paper, we finally study the question of whether the H-ENA population could even be understood as a self-consistency phenomenon of the H-ENA population, especially during solar activity minimum conditions, i.e., H-ENAs leaving the exosphere being replaced by H-ENAs injected into the exosphere.

  20. Neutralized solar wind ahead of the Earth's magnetopause as contribution to non-thermal exospheric hydrogen

    Science.gov (United States)

    Fahr, Hans J.; Nass, Uwe; Dutta-Roy, Robindro; Zoennchen, Jochen H.

    2018-03-01

    In a most recent paper by Qin and Waldrop (2016), it had been found that the scale height of hydrogen in the upper exosphere of the Earth, especially during solar minimum conditions, appears to be surprisingly large. This indicates that during minimum conditions when exobasic temperatures should be small, large exospheric H-scale heights predominate. They thus seem to indicate the presence of a non-thermal hydrogen component in the upper exosphere. In the following parts of the paper we shall investigate what fraction of such expected hot hydrogen atoms could have their origin from protons of the shocked solar wind ahead of the magnetopause converted into energetic neutral atoms (ENAs) via charge-exchange processes with normal atmospheric, i.e., exospheric hydrogen atoms that in the first step evaporate from the exobase into the magnetosheath plasma region. We shall show that, dependent on the sunward location of the magnetopause, the density of these types of non-thermal hydrogen atoms (H-ENAs) becomes progressively comparable with the density of exobasic hydrogen with increasing altitude. At low exobasic heights, however, their contribution is negligible. At the end of this paper, we finally study the question of whether the H-ENA population could even be understood as a self-consistency phenomenon of the H-ENA population, especially during solar activity minimum conditions, i.e., H-ENAs leaving the exosphere being replaced by H-ENAs injected into the exosphere.

  1. Neutralizing trapped electrons on the hydrogenated surface of a diamond amplifier

    Directory of Open Access Journals (Sweden)

    Xiangyun Chang

    2012-01-01

    Full Text Available We discuss our investigation of electron trapping in a diamond amplifier (DA. Our previous work demonstrated that some electrons reaching the DA’s hydrogenated surface are not emitted. The state and the removal of these electrons is important for DA applications. We found that these stopped electrons are trapped, and cannot be removed by a strong reversed-polarity electric field; to neutralize this surface charge, holes must be sent to the hydrogenated surface to recombine with the trapped electrons through the Shockley-Read-Hall surface-recombination mechanism. We measured the time taken for such recombination on the hydrogenated surface, viz. the recombination time, as less than 5 ns, limited by the resolution of our test system. With this measurement, we demonstrated that DA could be operated in an rf cavity with frequency of a few hundred megahertz.

  2. Spectroscopic Studies of Neutral and Ionized Solid Hydrogen and Gasesous Hydrogen Plasmas

    National Research Council Canada - National Science Library

    Oka, Takeshi

    1998-01-01

    ...=0 -0 in para-hydrogen (p-H2) crystals. Such transitions are clearly highly forbidden in the ordinary electric dipole selection rules and the transitions have to be of the second-order Raman type in which the transition moment M is given...

  3. Interstellar Hydrogen in Galaxies: Radio observations of neutral hydrogen yield valuable information on the properties of galaxies.

    Science.gov (United States)

    Roberts, M S

    1974-02-01

    Measurement of the 21-cm line radiation originating from the interstellar neutral hydrogen in a galaxy yields information on the total mass and total hydrogen content of the galaxy. The ratio of these two quantities is correlated with structural type in the sense that the later type galaxies contain a higher fraction of their total mass in the form of interstellar hydrogen This ratio is one of the few physical parameters known to correlate with structural type. It need not, however, reflect an evolutionary sequence, such as more hydrogen implying a younger galaxy. Efficiency of conversion of hydrogen to stars can just as easily explain the correlation. Except for the very latest systems, the total mass of a spiral does not appear to be correlated with type. Red shifts of galaxies measured at optical wavelengths and at 21 cm are in excellent agreement. The form of the Doppler expression has been shown to hold over a wavelength range of 5 x 105. All spirals earlier than type Ir which have been studied with adequate resolution show a central minimum in their hydrogen distribution. The region of maximum projected HI surface density occurs at some distance from the center. In the earlier type spirals the optical arms are located in the region of this maximum surface density. In the later type spirals the maximum HI density and prominent optical arms are less well correlated and, at times, are anticorrelated. Detailed studies of the HI distribution and motions within a galaxy require the high relative resolution of beam synthesis arrays. We may expect significant new information from such studies, which are now in progress. Filled-aperture telescopes will supply the necessary observations at zero spacing and vital statistical information on large numbers of galaxies, peculiar systems and groups and clusters of galaxies. The two types of telescope systems will complement one another. In the near future we should have a much better description of spiral galaxies and, we

  4. Absorption and fluorescence spectra of the neutral and anionic green fluorescent protein chromophore: Franck-Condon simulation

    Science.gov (United States)

    Huang, Tsung-wei; Yang, Ling; Zhu, Chaoyuan; Lin, Sheng Hsien

    2012-07-01

    Absorption and fluorescence spectra of the neutral and anionic green fluorescent protein (GFP) chromophore, namely p-hydroxybenzylideneimidazolidinone (p-HBDI), have been simulated using the Franck-Condon factors including inhomogeneous broadening of solvent effect. Ground and the first excited states were calculated by time dependent density functional theory with and without the polarizable continuum model environment. Simulated peak of the neutral/anionic p-HBDI at 380 nm (423 nm)/421 nm agrees with experiment value 370 nm (434 nm)/419 nm for absorption (fluorescence) spectrum. Simulated width of the neutral/anionic p-HBDI at 0.51 eV (0.54 eV)/0.57 eV agrees with experiment value 0.54 eV (0.66 eV)/0.56 eV for absorption (fluorescence) spectrum.

  5. The use of infrared absorption to determine density of liquid hydrogen.

    Science.gov (United States)

    Unland, H. D.; Timmerhaus, K. D.; Kropschot, R. H.

    1972-01-01

    Experimental evaluation of the use of infrared absorption for determining the density of liquid hydrogen, and discussion of the feasibility of an airborne densitometer based on this concept. The results indicate that infrared absorption of liquid hydrogen is highly sensitive to the density of hydrogen, and, under the operating limitations of the equipment and experimental techniques used, the determined values proved to be repeatable to an accuracy of 2.7%. The desiderata and limitations of an in-flight density-determining device are outlined, and some of the feasibility problems are defined.

  6. High stability of palladium/kieselguhr composites during absorption/desorption cycling for hydrogen isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yang, E-mail: lei.y@outlook.com; Liu, Xiaopeng; Li, Shuo; Jiang, Lijun; Zhang, Chao; Li, Shuai; He, Di; Wang, Shumao

    2016-12-15

    Highlights: • Pd/K composites with as high as 57 wt.% of Pd have been successfully prepared. • Palladium particles can be effectively packed into the pores of kieselguhr substrates. • Variation of heat-treatment temperatures hardly affect hydrogen absorption capacity and hydrogen saturation time of the Pd/K. • Anti-pulverization property of Pd/K can be improved by packing palladium into the kieselguhr internal pores and heating at 1300 °C. - Abstract: Palladium/kieselguhr (Pd/K) composites with 57 wt.% of Pd were prepared by an improved dipping and thermal decomposition method and heated at elevated temperature to reduce breakdown during hydrogenation-dehydrogenation cycles. The hydrogen absorption kinetic properties of the samples heated at different temperatures were tested under the condition of 20 °C with 100 kPa hydrogen pressure. The 1300 °C heated Pd/K composites were repeated up to 4010 absorption and desorption cycles at temperature ranges between −40 °C and 200 °C. The results show that the phase structure, hydrogen absorption capacity and hydrogen saturation time of the Pd/K were not affected by the change of heat-treated temperatures. And after heat treatment at 1300 °C, the Pd/K particles were strengthened and fraction of larger than 80 mesh were as high as 93.4%.

  7. An experimental investigation of the rate of hydrogen absorption in zirconium-2.5 wt percent niobium from steam/hydrogen mixtures at elevated temperatures

    International Nuclear Information System (INIS)

    Langman, V.J.

    1984-08-01

    The test specifications for an experimental program to study the rate of hydrogen absorption in zirconium-2.5 weight percent niobium pressure tube material from steam/hydrogen mixtures at elevated temperatures are discussed

  8. Characterizing the 21-cm Signal from Neutral Hydrogen in the IGM at Redshifts 27>z>6 with EDGES

    Science.gov (United States)

    Monsalve, Raul A.; Rogers, Alan E. E.; Bowman, Judd D.; Mozdzen, Thomas J.; Mahesh, Nivedita

    2018-01-01

    Understanding the period when the first stars formed and ionized the InterGalactic Medium (IGM) during the Epoch of Reionization (EoR) represents one of the main objectives of modern cosmology. The Experiment to Detect the Global EoR Signature (EDGES) strives to characterize this period by measuring, for the first time, the all-sky spectrum of the 21-cm signal produced by neutral hydrogen in the IGM at redshifts 27>z>6. In this talk I will describe recent EDGES constraints for the 21-cm signal. Specifically, with measurements from the EDGES High-Band instrument in the range 90-190 MHz, we rule out traditional Tanh models for the epoch of reionization with durations of up to dz=1 over the redshift range 14>z>7. We also rule out a wide range of phenomenological and physically-motivated 21-cm models that contain a large absorption feature in this redshift range, produced by the complex interaction between UV and X-ray radiation from the first sources and the neutral hydrogen in the IGM. Finally, I will describe our efforts to detect the 21-cm signal in the range 27>z>13 with two Low-Band instruments that have observed over 50-100 MHz since 2015. These instruments implement refined calibration techniques and lessons learned from previous generations of EDGES, and have achieved a level of systematic uncertainty low enough to enable detection. I will present Low-Band analysis results, including a variety of cross-checks performed to discriminate between residual instrumental effects and spectral structure that is intrinsic to the sky. I will conclude by describing the preparation of the next observational campaign with upgraded instrumentation.

  9. Renewable Hydrogen Carrier — Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    Directory of Open Access Journals (Sweden)

    Y.-H. Percival Zhang

    2011-01-01

    Full Text Available The hydrogen economy presents an appealing energy future but its implementation must solve numerous problems ranging from low-cost sustainable production, high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density hydrogen carrier and energy source for hydrogen production is possible due to emerging cell-free synthetic biology technology—cell-free synthetic pathway biotransformation (SyPaB. Assembly of numerous enzymes and co-enzymes in vitro can create complicated set of biological reactions or pathways that microorganisms or catalysts cannot complete, for example, C6H10O5 (aq + 7 H2O (l à 12 H2 (g + 6 CO2 (g (PLoS One 2007, 2:e456. Thanks to 100% selectivity of enzymes, modest reaction conditions, and high-purity of generated hydrogen, carbohydrate is a promising hydrogen carrier for end users. Gravimetric density of carbohydrate is 14.8 H2 mass% if water can be recycled from proton exchange membrane fuel cells or 8.33% H2 mass% without water recycling. Renewable carbohydrate can be isolated from plant biomass or would be produced from a combination of solar electricity/hydrogen and carbon dioxide fixation mediated by high-efficiency artificial photosynthesis mediated by SyPaB. The construction of this carbon-neutral carbohydrate economy would address numerous sustainability challenges, such as electricity and hydrogen storage, CO2 fixation and long-term storage, water conservation, transportation fuel production, plus feed and food production.

  10. Hydrogen Absorption in Weldments of Overlaid Claded Pressure Vessel

    Directory of Open Access Journals (Sweden)

    Ronnie Rusli

    2010-10-01

    Full Text Available Cracks was found in type 347 stainless steel internal attachment welds of a reactor for a high temperature, and highpressure hydrogen service. One of the possible causes of cracking is low cycle fatigue cracking induced by repetition ofthermal stress to embrittled weld metal. Type 347 weld metal loses its ductility by presence of sigma phase andhydrogen.

  11. Neutral Hydrogen Clouds near Early-Type Dwarf Galaxies of the Local Group

    OpenAIRE

    Bouchard, A.; Carignan, C.; Staveley-Smith, L.

    2006-01-01

    Parkes neutral hydrogen 21 cm line (HI) observations of the surroundings of 9 early-type Local Group dwarfs are presented. We detected numerous HI clouds in the general direction of those dwarfs and these clouds are often offset from the optical center of the galaxies. Although all the observed dwarfs, except Antlia, occupy phase-space regions where the High-Velocity Cloud (HVC) density is well above average, the measured offsets are smaller than one would expect from a fully random cloud dis...

  12. Hydrogen absorption study of Ti-based alloys performed by melt-spinning

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, R.M.; Lemus, L.F.; Santos, D.S. dos, E-mail: rafaella@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    The hydrogen absorption and desorption of Ti{sub 53}Zr{sub 27}Ni{sub 20} icosahedral quasicrystal (ICQ) and Ti{sub 50}Ni{sub 50} shape memory alloy (SMA) melt-spun ribbons was studied. Samples were exposed to hydrogen gas at 623 K and 4 MPa for 1000 minutes. The total capacity of hydrogen obtained for Ti{sub 53}Zr{sub 27}Ni{sub 20} and Ti{sub 50}Ni{sub 50} was 3.2 and 2.4 wt. % respectively. The Thermal Desorption Spectrometry (TDS) of the hydrogenated alloys shows that both alloys start to desorb hydrogen around 750 K. X-ray diffraction (XRD) patterns, performed after hydrogenation, indicate a complete amorphization of the Ti{sub 53}Zr{sub 27}Ni{sub 20} i-phase alloy, while the Ti{sub 50}Ni{sub 50} alloy remained crystalline after hydride formation. (author)

  13. Hydrogen absorption/desorption characteristics of room temperature ...

    Indian Academy of Sciences (India)

    ... hydrogen storage materials are found to be formed within the range of 1.35 to 1.45 where ∼ 2.5 to 2.9 H/F.U. can be reversibly stored under the ideal operating conditions. The heat of the reaction is found to be ∼ 17 kJ/mol, which means these are promising candidates for stationary and short range mobile applications.

  14. Effect of cold rolling on the hydrogen absorption and desorption kinetics of Zircaloy-4

    International Nuclear Information System (INIS)

    Dupim, I.S.; Moreira, J.M.L.; Huot, J.; Santos, S.F.

    2015-01-01

    Metal matrix composites have been considered promising candidates as nuclear fuels for pressurized water reactors and also for nuclear waste management. Among others, Zircaloy is considered an excellent alternative for metallic matrix in such composites due to its excellent mechanical properties, high thermal conductivity and high corrosion resistance at operating temperatures. For manufacturing these fuels, a necessary step is the production of Zircaloy powder to be used as raw material. A feasible route to produce powders of refractory metals and alloys like Zircaloy is the hydriding and dehydriding process. For this type of processing route, hydrogen absorption and desorption should be performed at the lowest temperature and pressure possible in order to reduce the processing costs. In this paper, we investigated the hydrogen sorption kinetics of Zircaloy and the effect of cold rolling on the reaction rate. It was found that cold rolling greatly increases the hydrogenation kinetics and drastically reduces the dehydrogenation temperature. - Highlights: • The effects of temperature and pressure on the hydrogen reaction kinetics in Zircaloy-4 are analyzed. • The incubation time during absorption measurements increased for higher H2 pressures. • Changes in hydriding reaction kinetics at 1500 kPa of H 2 and 1.25 wt.% of absorption. • Cold rolling increased the hydrogen absorption kinetics and decreased the hydride decomposition temperature

  15. Theory of the Infrared Absorption in the Ordered Solid Hydrogen

    OpenAIRE

    Jun-ichi, IGARASHI; Department of Physics, Osaka University

    1982-01-01

    The infrared absorption coefficient in the ordered solid orthohydrogen is calculated by making use of our anharmonic theory for libron (J=1 excitation) and roton (J=3 excitation). The momentum dependence of the transition amplitudes has properly been taken into account in conformity with our formalism. The shape of vibrational bands including J=1,3 rotational excitations is figured out in good agreement with the experiment by Boggs, Clouter and Welsh. A similar study has also been done for th...

  16. Hydrogen absorption by zirconium alloy cladding tube with surface oxide film

    International Nuclear Information System (INIS)

    Uchida, Masaaki

    1991-08-01

    Hydrogen absorption kinetics of Zircaloy (2 and 4) and Zr-Nb (1% and 2.5%) cladding tubes were studied by heating in hydrogen gas after oxide film formation in steam, oxygen or air. Hydrogen absorption rate depended on the degree of pre-oxidation. In Zr-Nb, the absorption rate was also sensitive to the atmosphere used for pre-oxidation, whereas in Zircaloy the rate was relatively independent of the kind of oxidant. In all materials, pre-oxidation to the transition point was found to bring about high absorption rate in the subsequent hydriding step. After pre-oxidation to the post-transition region, hydrogen absorption rate by Zircaloy showed constant or slightly decreasing tendency with increasing oxidation level, whereas in Zr-Nb, particularly in Zr-2.5%Nb, the rate showed a clearly decreasing tendency depending on the pre-oxidation atmosphere. Different characteristics of Zircaloy and Zr-Nb can partly be explained in terms of different valencies of alloying elements which influence the lattice defect concentrations in the oxide films. (author)

  17. Observations and Interpretations of Energetic Neutral Hydrogen Atoms from the December 5, 2006 Solar Event

    Science.gov (United States)

    Mewaldt, R. A.; Leske, R. A.; Shih, A. Y.; Stone, E. C.; Barghouty, A. f.; Cohen, C. M. S.; Cummings, A. c.; Labrador, A. W.; vonRosenvinge, T. T.

    2009-01-01

    We discuss recently reported observations of energetic neutral hydrogen atoms (ENAs) from an X9 solar flare/coronal mass ejection event on 5 December 2006, located at E79. The observations were made by the Low Energy Telescopes (LETs) on STEREO A and B. Prior to the arrival of the main solar energetic particle (SEP) event at Earth, both LETs observed a sudden burst of 1.6 to 15 MeV energetic neutral hydrogen atoms produced by either flare or shock-accelerated protons. RHESSI measurements of the 2.2-MeV gamma-ray line provide an estimate of the number of interacting flare-accelerated protons in this event, which leads to an improved estimate of ENA production by flare-accelerated protons. Taking into account ENA losses, we find that the observed ENAs must have been produced in the high corona at heliocentric distances > or equal to 2 solar radii. Although there are no CME images from this event, it is shown that CME-shock-accelerated protons can, in principle, produce a time-history consistent with the observations.

  18. STEREO Observations of Energetic Neutral Hydrogen Atoms during the 5 December 2006 Solar Flare

    Science.gov (United States)

    Mewaldt, R. A.; Leske, R. A.; Stone, E. C.; Barghouty, A. F.; Labrador, A. W.; Cohen, C. M. S.; Cummings, A. C.; Davis, A. J.; vonRosenvinge, T. T.; Wiedenbeck, M. E.

    2009-01-01

    We report the discovery of energetic neutral hydrogen atoms emitted during the X9 solar event of December 5, 2006. Beginning 1 hour following the onset of this E79 flare, the Low Energy Telescopes (LETs) on both the STEREO A and B spacecraft observed a sudden burst of 1.6 to 15 MeV protons beginning hours before the onset of the main solar energetic particle (SEP) event at Earth. More than 70% of these particles arrived from a longitude within 10 of the Sun, consistent with the measurement resolution. The derived emission profile at the Sun had onset and peak times remarkably similar to the GOES soft X-ray profile and continued for more than an hour. The observed arrival directions and energy spectrum argue strongly that the particle events less than 5 MeV were due to energetic neutral hydrogen atoms (ENAs). To our knowledge, this is the first reported observation of ENA emission from a solar flare/coronal mass ejection. Possible origins for the production of ENAs in a large solar event are considered. We conclude that the observed ENAs were most likely produced in the high corona and that charge-transfer reactions between accelerated protons and partially-stripped coronal ions are an important source of ENAs in solar events.

  19. Dynamics of excimer laser-ablated aluminum neutral atom plume measured by dye laser resonance absorption photography

    International Nuclear Information System (INIS)

    Gilgenbach, R.M.; Ventzek, P.L.G.

    1991-01-01

    We report the first dye laser resonance absorption photographs of a single species of aluminum ground-state neutral atoms in the plume ablated from solid aluminum by KrF excimer laser radiation. Aluminum ground-state neutral atoms were diagnosed by illuminating the ablated plume with a dye laser tuned to the 3 2 P 1/2 --4 2 S 1/2 transition at 394.4 nm. Measurements have been performed in vacuum as well as in argon and air environments. Streaming velocities measured for neutral aluminum atoms in vacuum ranged from 0.5x10 6 cm/s at low excimer laser fluences of 1--2 J/cm 2 to 3.4x10 6 cm/s at high fluences of 7 J/cm 2 . Dye laser resonance absorption photography measurements of ablated aluminum in argon and air showed slower expansion at 50 and 200 Torr, while observations at 760 Torr indicate turbulent mixing of aluminum neutrals near the surface. Differences between data in argon and air may be due to oxidation of neutral aluminum atoms

  20. The corrosion rate and the hydrogen absorption behavior of titanium under anaerobic condition

    International Nuclear Information System (INIS)

    Suzuki, Hiroyuki; Taniguchi, Naoki

    2006-01-01

    Titanium is one of the candidate materials for overpacks as a high corrosion resistance metal. Hydrogen embrittlement is a main cause of the damage of long term integrity of titanium overpack. It is not well known about the corrosion resistance and hydrogen absorption behavior of titanium under anaerobic condition. In this study, the completely sealed ampoule test and the immersion test of titanium was carried out in aqueous solution and bentonite in order to obtain reliable data about the hydrogen generation rate and the ratio of hydrogen absorption in titanium. As the results of the tests with changing the environmental factors, obvious higher corrosion rates were observed at high carbonate (1 M) and high pH (pH 13) conditions due to the increase in the anodic reaction rate. In other condition, corrosion rate of titanium were estimated to be in the order of 10 -3 - 10 -2 μm/y. Almost all (<98%) of the hydrogen generated by corrosion was absorbed into titanium. Assuming that the time evolution of the hydrogen content in titanium follows linear law to make conservative assessment, the absorbed hydrogen content was estimated to be of 400-500 ppm in 1000 years. (author)

  1. Searching out the hydrogen absorption/desorption limiting reaction factors: Strategies allowing to increase kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Zeaiter, Ali, E-mail: ali.zeaiter@femto-st.fr; Chapelle, David; Nardin, Philippe

    2015-10-05

    Highlights: • A macro scale thermodynamic model that simulates the response of a FeTi-X hydride tank is performed, and validated experimentally. • A sensibility study to identify the most influent input variables that can changes very largely the reaction rate. - Abstract: Hydrogen gas has become one of the most promising energy carriers. Main breakthrough concerns hydrogen solid storage, specially based on intermetallic material use. Regarding the raw material abundance and cost, the AB type alloy FeTi is an auspicious candidate to store hydrogen. Its absorption/desorption kinetics is a basic hindrance to common use, compared with more usual hydrides. First, discussions based on literature help us identifying the successive steps leading to metal hydriding, and allow to introduce the physical parameters which drive or limit the reaction. This analysis leads us to suggest strategies in order to increase absorption/desorption kinetics. Attention is then paid to a thermofluidodynamic model, allowing to describe a macroscopic solid storage reactor. Thus, we can achieve a simulation which describes the overall reaction inside the hydrogen reactor and, by varying the sub-mentioned parameters (thermal conductivity, the powder granularity, environment heat exchange…), we attempt to hierarchy the reaction limiting factors. These simulations are correlated to absorption/desorption experiments for which pressure, temperature and hydrogen flow are recorded.

  2. Thermodynamic modelling and kinetics of hydrogen absorption associated with phase transformations; Modelisation thermodynamique et cinetiques d'absorption de l'hydrogene associees aux transformations de phase

    Energy Technology Data Exchange (ETDEWEB)

    Gondor, G.; Lexcellent, Ch. [LMARC FEMTO-ST, 25 - Besancon (France)

    2007-07-01

    The intermetallic are used for hydrogen pressure containers in order to avoid leaks in the case of an hybrid container. The hydrogen atoms are absorbed by the intermetallic which act as a hydrogen sponge. This hydrogen absorption must be modelled for the container design. The Pressure-composition isotherms describe the equilibrium. Out of this equilibrium the kinetics are controlled by different processes, without taking into account the phase transformations. The author presents a new model of the p-c isotherms with the hydrogen absorption kinetics. (A.L.B.)

  3. Improved hydrogen absorption and desorption kinetics of magnesium-based alloy via addition of yttrium

    Science.gov (United States)

    Yang, Tai; Li, Qiang; Liu, Ning; Liang, Chunyong; Yin, Fuxing; Zhang, Yanghuan

    2018-02-01

    Yttrium (Y) is selected to modify the microstructure of magnesium (Mg) to improve the hydrogen storage performance. Thereby, binary alloys with the nominal compositions of Mg24Yx (x = 1-5) are fabricated by inexpensive casting technique. Their microstructure and phase transformation during hydriding and dehydriding process are characterized by using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy analysis. The isothermal hydrogen absorption and desorption kinetics are also measured by a Sievert's-type apparatus at various temperatures. Typical multiphase structures of binary alloy can be clearly observed. All of these alloys can reversibly absorb and desorb large amount of hydrogen at proper temperatures. The addition of Y markedly promotes the hydrogen absorption kinetics. However, it results in a reduction of reversible hydrogen storage capacity. A maximum value of dehydrogenation rate is observed with the increase of Y content. The Mg24Y3 alloy has the optimal desorption kinetic performance, and it can desorb about 5.4 wt% of hydrogen at 380 °C within 12 min. Combining Johnson-Mehl-Avrami kinetic model and Arrhenius equation, the dehydrogenation activation energy of the alloys are evaluated. The Mg24Y3 alloy also has the lowest dehydrogenation activation energy (119 kJ mol-1).

  4. Model Insensitive and Calibration Independent Method for Determination of the Downstream Neutral Hydrogen Density Through Ly-alpha Glow Observations

    Science.gov (United States)

    Gangopadhyay, P.; Judge, D. L.

    1996-01-01

    Our knowledge of the various heliospheric phenomena (location of the solar wind termination shock, heliopause configuration and very local interstellar medium parameters) is limited by uncertainties in the available heliospheric plasma models and by calibration uncertainties in the observing instruments. There is, thus, a strong motivation to develop model insensitive and calibration independent methods to reduce the uncertainties in the relevant heliospheric parameters. We have developed such a method to constrain the downstream neutral hydrogen density inside the heliospheric tail. In our approach we have taken advantage of the relative insensitivity of the downstream neutral hydrogen density profile to the specific plasma model adopted. We have also used the fact that the presence of an asymmetric neutral hydrogen cavity surrounding the sun, characteristic of all neutral densities models, results in a higher multiple scattering contribution to the observed glow in the downstream region than in the upstream region. This allows us to approximate the actual density profile with one which is spatially uniform for the purpose of calculating the downstream backscattered glow. Using different spatially constant density profiles, radiative transfer calculations are performed, and the radial dependence of the predicted glow is compared with the observed I/R dependence of Pioneer 10 UV data. Such a comparison bounds the large distance heliospheric neutral hydrogen density in the downstream direction to a value between 0.05 and 0.1/cc.

  5. Neutral hydrogen in the neighborhood of the supernova remnant W 50

    International Nuclear Information System (INIS)

    Gosachinskii, I.V.; Khersonskii, V.K.

    1987-01-01

    Observations of neutral hydrogen at wavelength 21 cm in the neighborhood of the supernova remnant W 50, which contains the unique object SS 433, have been made with the RATAN-600 radio telescope with resolution 2' x 130' x 6.3 km/sec. At a radial velocity of about 34 km/sec (kinematic distance 3 kpc) a patchy HI cloud is found with outer diameter 65 pc and mass ∼ 3 x 10 4 M/sub circle/. In addition, at radial velocity 69 km/sec (kinematic distances 5.0 or 10.7 kpc) there is a HI cloud without appreciable large-scale motions. Some models that could explain the connection between these objects and the observed HI clouds are considered

  6. phi-meson photoproduction on Hydrogen in the neutral decay mode

    Energy Technology Data Exchange (ETDEWEB)

    Seraydaryan, Helena [ODU; Amaryan, Moscov J. [ODU; Gavalian, Gagik [JLAB; Baghdasaryan, Hovhannes A. [UVA; Weinstein, Larry [ODU

    2014-05-01

    We report the first measurement of the photoproduction cross section of the $\\phi$ meson in its neutral decay mode in the reaction $\\gamma p \\to p\\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \\le E_\\gamma \\le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \\phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\\gamma p \\to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\\phi$ photoproduction.

  7. Northern dwarf and low surface brightness galaxies. II - The Green Bank neutral hydrogen survey

    Science.gov (United States)

    Schneider, Stephen E.; Thuan, Trinh X.; Mangum, Jeffrey G.; Miller, John

    1992-01-01

    The paper reports neutral hydrogen observations of a large sample of dwarf and other low surface brightness galaxies. A detailed discussion and error analysis of the observations are presented, and spectra are displayed for 329 galaxies detected for the first time, or detected with substantially better signal-to-noise ratios than achieved previously. The positions on the sky of 667 galaxies meeting the present selection criteria north of delta = 38 deg are shown. The distribution of the redshifts of galaxies detected at Green Bank is illustrated. The Green Bank detections tapered off strongly below the median H I flux of 3.7 Jy km/s detected at Arecibo: only 12 percent of the Green Bank sample was detected with smaller fluxes.

  8. 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

  9. Poly(neutral red) based hydrogen peroxide biosensor for chromium determination by inhibition measurements.

    Science.gov (United States)

    Attar, Aisha; Emilia Ghica, M; Amine, Aziz; Brett, Christopher M A

    2014-08-30

    Amperometric hydrogen peroxide enzyme inhibition biosensors based on horseradish peroxidase (HRP) immobilised on electropolymerised neutral red (NR) or directly on the surface of carbon film electrodes (CFE) have been successfully applied to the determination of toxic Cr(III) and Cr(VI). Parameters influencing the performance of the biosensor including the enzyme immobilisation method, the amount of hydrogen peroxide, applied potential and electrolyte pH were optimised. The inhibition of horseradish peroxidase by the chromium species was studied under the optimised conditions. Results from the quantitative analysis of chromium ions are discussed in terms of detection limit, linear range and sensitivity. The HRP kinetic interactions reveal mixed binding of Cr(III) with I50=3.8μM and inhibition binding constant Ki=11.3μM at HRP/PNR/CFE biosensors and uncompetitive binding of Cr(VI) with I50=3.9μM and Ki=0.78μM at HRP/CFE biosensors in the presence of H2O2 substrate. Interferences from other heavy metal ions were studied and the inhibition show very good selectivity towards Cr(III) and Cr(VI). Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Observations of Mercury’s Neutral Hydrogen Exosphere During the MESSENGER Orbital Phase

    Science.gov (United States)

    Vervack, Ronald J.; Hurley, Dana; Pryor, Wayne R.

    2017-10-01

    Because of the difficulty of observing H Lyman α at Mercury remotely, the MESSENGER mission afforded the first chance since the Mariner 10 flybys to investigate the neutral hydrogen exosphere of Mercury in detail. Mariner 10 discovered H at Mercury, but left many questions about the puzzling temperature and density distributions unanswered. Sparse observations during the MESSENGER flybys of Mercury suggested that the H exosphere was grossly similar to what was observed by Mariner 10, but with higher overall emission levels, and they provided no answers to the outstanding issues from Mariner 10. Observations of H Lyman α emission by the Ultraviolet and Visible Spectrometer (UVVS) component of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument onboard MESSENGER were conducted regularly throughout the MESSENGER orbital phase. These observations provide a much more complete picture of the H exosphere at Mercury. We present an analysis of the UVVS orbital observations, focusing on the temporal and spatial distribution of the hydrogen about the planet. Preliminary models will be shown, and the UVVS data will be compared and contrasted to the Mariner 10 data to address the long-outstanding questions about this element of Mercury’s complex exosphere. Support from the NASA Discovery Data Analysis Program is gratefully acknowledged.

  11. Increasing Solar Absorption for Photocatalysis with Black Hydrogenated Titanium Dioxide Nanocrystals

    KAUST Repository

    Chen, X.

    2011-01-20

    When used as a photocatalyst, titanium dioxide (TiO 2) absorbs only ultraviolet light, and several approaches, including the use of dopants such as nitrogen, have been taken to narrow the band gap of TiO 2. We demonstrated a conceptually different approach to enhancing solar absorption by introducing disorder in the surface layers of nanophase TiO 2 through hydrogenation. We showed that disorder-engineered TiO 2 nanocrystals exhibit substantial solar-driven photocatalytic activities, including the photo-oxidation of organic molecules in water and the production of hydrogen with the use of a sacrificial reagent.

  12. Sound Absorption Properties Of Single-Hole Hollow Polyester Fiber Reinforced Hydrogenated Carboxyl Nitrile Rubber Composites

    Directory of Open Access Journals (Sweden)

    Jie Hong

    2017-09-01

    Full Text Available A series of single-hole hollow polyester fiber (SHHPF reinforced hydrogenated carboxyl nitrile rubber (HXNBR composites were fabricated. In this study, the sound absorption property of the HXNBR/SHHPF composite was tested in an impedance tube, the composite morphology was characterized by scanning electron microscope (SEM, and the tensile mechanical property was measured by strength tester. The results demonstrated that a remarkable change in sound absorption can be observed by increasing the SHHPF content from 0% to 40%. In the composite with 40% SHHPF in 1 mm thickness, the sound absorption coefficient reached 0.671 at 2,500 Hz; the effective bandwidth was 1,800-2,500 Hz for sound absorption coefficient larger than 0.2. But the sound absorption property of the composite deteriorated when the SHHPF content increased to 50% in 1 mm thickness. While with 20% SHHPF proportion, the sound absorption property was improved by increasing the thickness of composites from 1 to 5 mm. Compared with the pure HXNBR of the same thickness, the tensile mechanical property of the composite improved significantly by increasing the SHHPF proportion. As a lightweight composite with excellent sound absorption property, the HXNBR/SHHPF composite has potential practical application value in the fields of engineering.

  13. Hydrogen adsorption and hydrogen evolution reaction on a polycrystalline Pt electrode studied by surface-enhanced infrared absorption spectroscopy

    International Nuclear Information System (INIS)

    Kunimatsu, Keiji; Senzaki, Takahiro; Samjeske, Gabor; Tsushima, Minoru; Osawa, Masatoshi

    2007-01-01

    Hydrogen evolution reaction (HER) on a polycrystalline Pt electrode has been investigated in Ar-purged acids by surface-enhanced infrared absorption spectroscopy and electrochemical kinetic analysis (Tafel plot). A vibrational mode characteristic to H atom adsorbed at atop sites (terminal H) was observed at 2080-2095 cm -1 . This band appears at 0.1 V (RHE) and grows at more negative potentials in parallel to the increase in hydrogen evolution current. Good signal-to-noise ratio of the spectra enabled us to establish the quantitative relation between the band intensity (equivalently, coverage) of terminal H and the kinetics of HER, from which we conclude that terminal H atom is the reaction intermediate in HER and the recombination of two terminal H atoms is the rate-determining step. The quantitative analysis of the infrared data also revealed that the adsorption of terminal H follows the Frumkin isotherm with repulsive interaction

  14. Low temperature absorption of hydrogen isotopes on potassium-graphite intercalation compounds prepared from carbon fibers and HOPG

    International Nuclear Information System (INIS)

    Akuzawa, N.; Amemiya, T.; Terai, T.; Takahashi, Y.

    1984-01-01

    Hydrogen absorption behavior of potassium-carbon intercalation compounds (KCsub(x)), prepared from PAN based carbon fiber, benzene derived vapor grown carbon fiber and highly oriented pyrolytic graphite, was investigated by measuring the isotherms of hydrogen- and deuterium-gas absorption and the H 2 - D 2 isotopic partition coefficient at 77 K. The absorption behavior was somewhat different from those of KCsub(x) prepared from natural or artificial graphite powders: The rate of absorption was very slow, especially at the early stage of experiment, and equilibrium absorption was attained only after several runs of absorption-desorption cycles. For KC 21 prepared from HOPG, a remarkable exfoliation was observed by the release of absorbed hydrogen. The isotopic partition coefficients of these samples were not very different from those of other KCsub(x) samples. (author)

  15. The kinetics of Cr layer coated on TiNi films for hydrogen absorption

    Indian Academy of Sciences (India)

    The effect of hydrogen absorption on electrical resistance with temperature for TiNi and TiNi–Cr thin films was investigated. The TiNi thin films of thickness 800 Å were deposited at different angles ( = 0°, 30°, 45°, 60° and 75°) under 10−5 Torr pressure by thermal evaporation on the glass substrate at room temperature.

  16. Evaluation of Ability of Hydrogen Absorption in SAB-16/Pd Nanostructure Composite

    Directory of Open Access Journals (Sweden)

    M.A. Yousefpour

    2015-12-01

    Full Text Available The purpose of this work was to study the hydrogen adsorption on the surface of mesoporous materials based on silica (SBA-16 modified with palladium via temperature. Since mesoporous silica materials have a high specific surface area, and the ordered mesoporous size of 2-10nm, they are suitable for adsorption and storage of hydrogen. SBA-16 is suitable for this purpose due to its cubic crystalstructure and open pores. Single-stage sol-gel method was used to produce nanostructure composite from salt of palladium (PdCl3 and mesoporous silica precursor. The aging time was selected as 12 hr at 80˚C. Furthermore, the obtained materials were heated at 550˚C for 6 hr to remove surfactant and to form pores. Then the materials were characterized by large angle and small angle x-ray diffraction analysis, and hydrogen absorption analysis at upto 200kPa pressure at three different temperatures of -196˚C (77 K, -123˚C (150 K and 30˚C (303 K. Furthermore, adsorption-desorption of nitrogen gas was studied. The surface morphology was observed by field emission scanning electron microscope (FESEM. In addition, the amount of palladium, oxygen, and silicon were measured by using energy dispersive spectroscopy EDS . Finally, the functional groups on the surface of mesoporous silica materials were evaluated using Fourier transform infrared spectroscopy (FTIR. The results of XRD and EDS analyses confirmed the presence of palladium and palladium oxide in mesoporous amorphous silica. In addition, BET results showed that addition of palladium in SBA-16 decreased the surface area, and produced 791 and 538m2/g for SBA-16 and SBA-16/Pd, respectively. Hydrogen absorption in nano structure composite was decreasing with temperatur in comparison with SAB-16. On the other hand, the maximum hydrogen absorption in the nano structure composite containing palladium was obtained at -196˚C (77 K.

  17. Deep neutral hydrogen observations of Leo T with the Westerbork Synthesis Radio Telescope

    Science.gov (United States)

    Adams, Elizabeth A. K.; Oosterloo, Tom A.

    2018-04-01

    Leo T is the lowest mass gas-rich galaxy currently known and studies of its gas content help us understand how such marginal galaxies survive and form stars. We present deep neutral hydrogen (H I) observations from the Westerbork Synthesis Radio Telescope in order to understand its H I distribution and potential for star formation. We find a larger H I line flux than the previously accepted value, resulting in a 50% larger H I mass of 4.1 × 105 M⊙. The additional H I flux is from low surface brightness emission that was previously missed; with careful masking this emission can be recovered even in shallower data. We perform a Gaussian spectral decomposition to find a cool neutral medium component (CNM) with a mass of 3.7 × 104 M⊙, or almost 10% of the total H I mass. Leo T has no H I emission extending from the main H I body, but there is evidence of interaction with the Milky Way circumgalactic medium in both a potential truncation of the H I body and the offset of the peak H I distribution from the optical center. The CNM component of Leo T is large when compared to other dwarf galaxies, even though Leo T is not currently forming stars and has a lower star formation efficiency than other gas-rich dwarf galaxies. However, the H I column density associated with the CNM component in Leo T is low. One possible explanation is the large CNM component is not related to star formation potential but rather a recent, transient phenomenon related to the interaction of Leo T with the Milky Way circumgalactic medium. The reduced datacube (FITS file) is only 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/viz-bin/qcat?J/A+A/612/A26

  18. Influence of hydrogen absorption in amorphous Ni-P electrodes on double layer capacitance and charge transfer coefficient of hydrogen evolution reaction

    Czech Academy of Sciences Publication Activity Database

    Paseka, Ivo

    1999-01-01

    Roč. 44, č. 25 (1999), s. 4551-4558 ISSN 0013-4686 R&D Projects: GA ČR GA203/96/1320 Institutional research plan: CEZ:AV0Z4032918 Keywords : hydrogen absorption * hydrogen evolution * Amorphous alloys * Nickel phosphorus electrodes Subject RIV: CA - Inorganic Chemistry Impact factor: 1.325, year: 1999

  19. Covalent modification of multiwalled carbon nanotubes with neutral red for the fabrication of an amperometric hydrogen peroxide sensor

    International Nuclear Information System (INIS)

    Jeykumari, D R Shobha; Narayanan, S Sriman

    2007-01-01

    The nanoscale dimensions, graphitic surface chemistry and electronic properties of multiwalled carbon nanotubes (MWNTs) make them an ideal candidate for chemical and biochemical sensing. In this paper we explore a covalent chemical strategy for functionalization of MWNTs with neutral red through carbodiimide coupling between the primary amine of neutral red and carboxyl groups of the carbon nanotubes. The construction of an amperometric sensor was achieved by abrasive immobilization of the functionalized MWNTs on a paraffin impregnated graphite electrode followed by a coating of a thin film of nafion. The neutral red functionalized MWNTs were characterized by spectroscopic and electroanalytical methods. From the voltammetric studies, MWNTs were found to exhibit a higher accessible surface area in electrochemical reactions. The modified electrode exhibited stable electrocatalytic activity toward hydrogen peroxide reduction in a wide potential range. A significant decrease in overvoltage for the reduction of hydrogen peroxide, as well as a dramatic increase in the peak currents in comparison with a bare graphite electrode were observed. Such an ability of neutral red functionalized carbon nanotubes to promote the hydrogen peroxide electron transfer reaction with a short response time (<4 s) and long-term stability, a low detection limit, an extended linear concentration range and a high sensitivity suggest great promise for dehydrogenase and oxidase based amperometric biosensors

  20. Covalent modification of multiwalled carbon nanotubes with neutral red for the fabrication of an amperometric hydrogen peroxide sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jeykumari, D R Shobha; Narayanan, S Sriman [Department of Analytical Chemistry, School of Chemical Sciences, University of Madras, Guindy Campus, Chennai-600 025 (India)

    2007-03-28

    The nanoscale dimensions, graphitic surface chemistry and electronic properties of multiwalled carbon nanotubes (MWNTs) make them an ideal candidate for chemical and biochemical sensing. In this paper we explore a covalent chemical strategy for functionalization of MWNTs with neutral red through carbodiimide coupling between the primary amine of neutral red and carboxyl groups of the carbon nanotubes. The construction of an amperometric sensor was achieved by abrasive immobilization of the functionalized MWNTs on a paraffin impregnated graphite electrode followed by a coating of a thin film of nafion. The neutral red functionalized MWNTs were characterized by spectroscopic and electroanalytical methods. From the voltammetric studies, MWNTs were found to exhibit a higher accessible surface area in electrochemical reactions. The modified electrode exhibited stable electrocatalytic activity toward hydrogen peroxide reduction in a wide potential range. A significant decrease in overvoltage for the reduction of hydrogen peroxide, as well as a dramatic increase in the peak currents in comparison with a bare graphite electrode were observed. Such an ability of neutral red functionalized carbon nanotubes to promote the hydrogen peroxide electron transfer reaction with a short response time (<4 s) and long-term stability, a low detection limit, an extended linear concentration range and a high sensitivity suggest great promise for dehydrogenase and oxidase based amperometric biosensors.

  1. Electrocatalytic hydrogen evolution under densely buffered neutral pH conditions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-08-18

    Under buffered neutral pH conditions, solute concentrations drastically influence the hydrogen evolution reaction (HER). The iR-free HER performance as a function of solute concentration was found to exhibit a volcano-shaped trend in sodium phosphate solution at pH 5, with the maximum occurring at 2 M. A detailed microkinetic model that includes calculated activity coefficients, solution resistance, and mass-transport parameters accurately describes the measured values, clarifying that the overall HER performance is predominantly governed by mass-transport of slow phosphate ions (weak acid). In the HER at the optimum concentration of approximately 2 M sodium phosphate at pH 5, our theoretical model predicts that the concentration overpotential accounts for more than half of the required overpotential. The substantial concentration overpotential would originate from the electrolyte property, suggesting that the proper electrolyte engineering will result in an improved apparent HER performances. The significance of concentration overpotential shown in the study is critical in the advancement of electrocatalysis, biocatalysis, and photocatalysis.

  2. Observation and Interpretation of Energetic Neutral Hydrogen Atoms from the December 5, 2006 Solar Flare

    Science.gov (United States)

    Barghouty, A. F.; Mewaldt, R. A.; Leske, R. A.; Shih, A. Y.; Stone, E. C.; Cohen, C. M. S.; Cummings, A. C.; Labrador, A. W.; vonRosenvinge, T. T.; Wiedenbeck, M. E.

    2009-01-01

    We discuss observations of energetic neutral hydrogen atoms (ENAs) from a solar flare/coronal mass ejection event reported by Mewaldt et al. (2009). The observations were made during the 5 December 2006 X9 solar flare, located at E79, by the Low Energy Telescopes (LETs) on STEREO A and B. Prior to the arrival of the main solar energetic particle (SEP) event at Earth, both LETs observed a sudden burst of 1.6 to 15 MeV particles arriving from the Sun. The derived solar emission profile, arrival directions, and energy spectrum all show that the atoms produced by either flare or shock-accelerated protons. RHESSI measurements of the 2.2-MeV gamma-ray line provide an estimate of the number of interacting flare-accelerated protons in this event, which leads to an improved estimate of ENA production by flare-accelerated protons. CME-driven shock acceleration is also considered. Taking into account ENA losses, we conclude that the observed ENAs must have been produced in the high corona at heliocentric distances .2 solar radii.

  3. Blowing in the Milky Way Wind: Neutral Hydrogen Clouds Tracing the Galactic Nuclear Outflow

    Science.gov (United States)

    Di Teodoro, Enrico M.; McClure-Griffiths, N. M.; Lockman, Felix J.; Denbo, Sara R.; Endsley, Ryan; Ford, H. Alyson; Harrington, Kevin

    2018-03-01

    We present the results of a new sensitive survey of neutral hydrogen above and below the Galactic Center with the Green Bank Telescope. The observations extend up to Galactic latitude | b| Accounting for selection effects, the cloud population is symmetric in longitude, latitude, and V LSR. We model the cloud kinematics in terms of an outflow expanding from the Galactic Center and find the population consistent with being material moving with radial velocity {V}{{w}}≃ 330 {km} {{{s}}}-1 distributed throughout a bicone with opening angle α > 140^\\circ . This simple model implies an outflow luminosity {L}{{w}}> 3× {10}40 erg s‑1 over the past 10 Myr, consistent with star formation feedback in the inner region of the Milky Way, with a cold gas mass-loss rate ≲ 0.1 {{M}ȯ {yr}}-1. These clouds may represent the cold gas component accelerated in the nuclear wind driven by our Galaxy, although some of the derived properties challenge current theoretical models of the entrainment process.

  4. Behavior of charge-transfer absorption upon passing through the neutral-ionic phase transition

    DEFF Research Database (Denmark)

    Jacobsen, Claus Schelde; Torrance, J. B.

    1983-01-01

    The charge-transfer band is determined from reflectance measurements on single crystals of TTF-chloranil from 300 to 45 K, passing through the neutral-ionic phase transition at 84 K. As the temperature is decreased from 300 K toward the transition, hnuCT decreases slowly from 0.66 to 0.55 eV, per...

  5. Concentration of atomic hydrogen in a dielectric barrier discharge measured by two-photon absorption fluorescence

    Science.gov (United States)

    Dvořák, P.; Talába, M.; Obrusník, A.; Kratzer, J.; Dědina, J.

    2017-08-01

    Two-photon absorption laser-induced fluorescence (TALIF) was utilized for measuring the concentration of atomic hydrogen in a volume dielectric barrier discharge (DBD) ignited in mixtures of Ar, H2 and O2 at atmospheric pressure. The method was calibrated by TALIF of krypton diluted in argon at atmospheric pressure, proving that three-body collisions had a negligible effect on quenching of excited krypton atoms. The diagnostic study was complemented with a 3D numerical model of the gas flow and a zero-dimensional model of the chemistry in order to better understand the reaction kinetics and identify the key pathways leading to the production and destruction of atomic hydrogen. It was determined that the density of atomic hydrogen in Ar-H2 mixtures was in the order of 1021 m-3 and decreased when oxygen was added into the gas mixture. Spatially resolved measurements and simulations revealed a sharply bordered region with low atomic hydrogen concentration when oxygen was added to the gas mixture. At substoichiometric oxygen/hydrogen ratios, this H-poor region is confined to an area close to the gas inlet and it is shown that the size of this region is not only influenced by the chemistry but also by the gas flow patterns. Experimentally, it was observed that a decrease in H2 concentration in the feeding Ar-H2 mixture led to an increase in H production in the DBD.

  6. Crystallographic and magnetic property changes upon hydrogen absorption in Hf2Fe

    International Nuclear Information System (INIS)

    Vulliet, P.; Teisseron, G.; Jeandey, C.; Oddou, J.L.; Yaouanc, A.

    1984-04-01

    We have found that the cubic intermetallic compound Hf 2 Fe can absorb almost up to five hydrogen atoms per formula at a pressure of one atmosphere. Hf 2 Fe is a Pauli magnet. Upon hydrogen absorption a magnetic moment definitively appears on iron, starting at approximately 1.5 hydrogen concentration. A maximum in the saturation magnetic moment is observed in Hf 2 FeH 3 . The static low field susceptibility presents a maximum value and a non reversible behaviour. These properties are characteristic of a disordered magnetic system (spin-glass like). The γ-γ perturbed angular correlation spectra indicate that at low concentration, the hydrogen is localized only near one type of Hf. From our Moessbauer data we measure a shift in the isomer-shift which is consistent with what is already known. When decreasing the temperature and increasing the hydrogen concentration the spectra get less resolved. This is linked to the fact that the samples are in a disordered magnetic phase

  7. Neutralization study of boron and some metallic impurities (gold, titanium, manganese, chromium) by hydrogen implantation in monocrystal silicon

    International Nuclear Information System (INIS)

    Zundel, T.

    1987-02-01

    Boron doped silicon implanted with hydrogen at low energy in the temperature range 80-140 0 C shows a large decrease of the electrically active dopant concentration up to a depth which increases with the temperature, the implantation duration and the starting material resistivity. This effect is assigned to the formation of an electrically inactive BH complex. The hydrogen incorporation process shows a weakly temperature dependent enhanced diffusion step followed by a normal diffusion phase which may be described by a thermally activated diffusion coefficient. Heating at 80 0 C produces a complete dissociation of the BH complexes in the space charge region of reverse biased Schottky diodes. Consequently the released hydrogen drifts under the electric field and the neutralization becomes more pronounced in the bulk. Hydrogen neutralizes the gold, chromium, manganese related deep levels but has no effect on titanium related defect levels. Thermal annealing at 495 0 C of hydrogenated chromium or manganese doped samples produces four majority carriers levels which disappear at 700 0 C [fr

  8. Hydrogen absorption and desorption in a duplex-annealed Ti-6Al-4V alloy during exposure to different hydrogen-containing environments

    International Nuclear Information System (INIS)

    Eliezer, D.; Tal-Gutelmacher, E.; Cross, C.E.; Boellinghaus, Th.

    2006-01-01

    Based on its excellent combination of a high strength/weight ratio and good corrosion behavior, Ti-6Al-4V alloy is ranked among the most important advanced materials for a variety of industrial applications. However, in many of these technological applications, this alloy is exposed to environments which can act as sources of hydrogen, and severe problems may arise based on its susceptibility to hydrogen embrittlement. Even small hydrogen concentrations might lead to failure. Consequently, a comprehensive knowledge of hydrogen's absorption/desorption behavior and interactions between hydrogen and different microstructural features is necessary to better understand the desorption and trapping mechanisms, the types of the trap sites, and the trapped hydrogen content, in order to determine the safe service conditions of this alloy in the industry. In this paper, different characteristics of hydrogen's absorption/desorption behavior and trapping in a duplex-annealed Ti-6Al-4V alloy are studied by means of thermal desorption spectroscopy (TDS). Spectra analysis is supported by data from a variety of other experimental techniques, such as LECO hydrogen determinator, XRD and microstructure investigations by means of optical and electron microscopy. Hydrogen evolution is found to be a very complex process, being affected by the way hydrogen was initially introduced to the alloy, the phase transformations that may occur during the thermal analysis and the presence of potential trapping sites

  9. A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides.

    Science.gov (United States)

    Powell, J R; Salzano, F J; Yu, W S; Milau, J S

    1976-07-23

    A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output.

  10. Predicted effects of mineral neutralization and bisulfate formation on hydrogen ion concentration for dilute sulfuric acid pretreatment.

    Science.gov (United States)

    Lloyd, Todd A; Wyman, Charles E

    2004-01-01

    Dilute acid and water-only hemicellulose hydrolysis are being examined as part of a multiinstitutional cooperative effort to evaluate the performance of leading cellulosic biomass pretreatment technologies on a common basis. Cellulosic biomass, such as agricultural residues and forest wastes, can have a significant mineral content. It has been shown that these minerals neutralize some of the acid during dilute acid pretreatment, reducing its effectiveness, and the higher solids loadings desired to minimize costs will require increased acid use to compensate. However, for sulfuric acid in particular, an equilibrium shift to formation of bisulfate during neutralization can further reduce hydrogen ion concentrations and compound the effect of neutralization. Because the equilibrium shift has a more pronounced effect at lower acid concentrations, additional acid is needed to compensate. Coupled with the effect of temperature on acid dissociation, these effects increase acid requirements to achieve a particular reaction rate unless minerals are removed prior to hydrolysis.

  11. Silica-Polypyrrole Hybrids as High-Performance Metal-Free Electrocatalysts for the Hydrogen Evolution Reaction in Neutral Media.

    Science.gov (United States)

    Feng, Jin-Xian; Xu, Han; Ye, Sheng-Hua; Ouyang, Gangfeng; Tong, Ye-Xiang; Li, Gao-Ren

    2017-07-03

    Constructing inorganic-organic hybrids with superior properties in terms of water adsorption and activation will lead to catalysts with significantly enhanced electrocatalytic activity in the hydrogen evolution reaction (HER) in environmentally benign neutral media. Herein, we report SiO 2 -polypyrrole (PPy) hybrid nanotubes supported on carbon fibers (CFs) (SiO 2  /PPy NTs-CFs) as inexpensive and high-performance electrocatalysts for the HER in neutral media. Because of the strong electronic interactions between SiO 2 and PPy, the SiO 2 uniquely serves as the centers for water adsorption and activation, and accordingly promotes the HER. The metal-free SiO 2  /PPy NTs-CFs displayed high catalytic activity in the HER in neutral media, such as a low onset potential and small Tafel slope, as well as excellent long-term durability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Ionisation of hydrogen-like atoms by a multiphoton absorption process

    International Nuclear Information System (INIS)

    Gontier, Y.; Trahin, M.

    1967-01-01

    The general expression for the amplitude of the probability of ionisation by a multiphoton absorption process is derived. Its non-relativistic limit is taken and the bipolar approximation is used for calculating the ionisation cross-section of hydrogen-like atoms. This latter involves the summation over intermediate virtual states by means of: a) a recursion relationship concerning angular functions, b) a particular technique which when applied to radial functions makes it possible to solve a system of inhomogeneous first-order differential equations. (authors) [fr

  13. Hydrogen peroxide vapor cross sections: A flow cell study using laser absorption in the near infrared

    Science.gov (United States)

    Rhodes, B. L.; Ronney, P. D.; DeSain, J. D.

    2018-01-01

    The absorption spectra of vapors of concentrated hydrogen peroxide/water mixtures (without a carrier gas) were characterized at wavelengths from 1390 to 1470 nm utilizing a near-infrared diode laser. Low pressures were employed to examine these spectral features near the Doppler-broadened limit. An advantageous portion of the spectra near 1420 nm containing several distinct H2O2 peaks and one well-known H2O peak (for calibration) was identified and the cross-sections of these peaks determined. These cross section values can be employed to measure vapor-phase concentrations of H2O2 in propulsion, atmospheric chemistry, and sterilization applications.

  14. Discovery of Variable Hydrogen Balmer Absorption Lines with Inverse Decrement in PG 1411+442

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xi-Heng; Pan, Xiang; Zhang, Shao-Hua; Sun, Lu-Ming; Ji, Tuo; Liu, Bo; Zhou, Hong-Yan [Polar Research Institute of China, Jinqiao Road 451, Shanghai 200136 (China); Wang, Jian-Guo [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Yang, Chen-Wei; Jiang, Ning, E-mail: zhouhongyan@pric.org.cn, E-mail: shixiheng@pric.org.cn [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)

    2017-07-01

    We present new optical spectra of the well-known broad absorption line (BAL) quasar PG 1411+442, using the DBSP spectrograph at the Palomar 200 inch telescope in 2014 and 2017 and the YFOSC spectrograph at the Lijiang 2.4 m telescope in 2015. A blueshifted narrow absorption line system is clearly revealed in 2014 and 2015 consisting of hydrogen Balmer series and metastable He i lines. The velocity of these lines is similar to the centroid velocity of the UV BALs, suggesting that both originate from the outflow. The Balmer lines vary significantly between the two observations and vanished in 2017. They were also absent in the archived spectra obtained before 2001. The variation is thought to be driven by photoionization change. Besides, the absorption lines show inversed Balmer decrement, i.e., the apparent optical depths of higher-order Balmer absorption lines are larger than those of lower-order lines, which is inconsistent with the oscillator strengths of the transitions. We suggest that such anomalous line ratios can be naturally explained by the thermal structure of a background accretion disk, which allows the obscured part of the disk to contribute differently to the continuum flux at different wavelengths. High-resolution spectroscopic and photometric monitoring would be very useful to probe the structure of the accretion disk as well as the geometry and physical conditions of the outflow.

  15. Discovery of Variable Hydrogen Balmer Absorption Lines with Inverse Decrement in PG 1411+442

    Science.gov (United States)

    Shi, Xi-Heng; Pan, Xiang; Zhang, Shao-Hua; Sun, Lu-Ming; Wang, Jian-Guo; Ji, Tuo; Yang, Chen-Wei; Liu, Bo; Jiang, Ning; Zhou, Hong-Yan

    2017-07-01

    We present new optical spectra of the well-known broad absorption line (BAL) quasar PG 1411+442, using the DBSP spectrograph at the Palomar 200 inch telescope in 2014 and 2017 and the YFOSC spectrograph at the Lijiang 2.4 m telescope in 2015. A blueshifted narrow absorption line system is clearly revealed in 2014 and 2015 consisting of hydrogen Balmer series and metastable He I lines. The velocity of these lines is similar to the centroid velocity of the UV BALs, suggesting that both originate from the outflow. The Balmer lines vary significantly between the two observations and vanished in 2017. They were also absent in the archived spectra obtained before 2001. The variation is thought to be driven by photoionization change. Besides, the absorption lines show inversed Balmer decrement, I.e., the apparent optical depths of higher-order Balmer absorption lines are larger than those of lower-order lines, which is inconsistent with the oscillator strengths of the transitions. We suggest that such anomalous line ratios can be naturally explained by the thermal structure of a background accretion disk, which allows the obscured part of the disk to contribute differently to the continuum flux at different wavelengths. High-resolution spectroscopic and photometric monitoring would be very useful to probe the structure of the accretion disk as well as the geometry and physical conditions of the outflow.

  16. Integrative CO2 Capture and Hydrogenation to Methanol with Reusable Catalyst and Amine: Toward a Carbon Neutral Methanol Economy.

    Science.gov (United States)

    Kar, Sayan; Sen, Raktim; Goeppert, Alain; Prakash, G K Surya

    2018-02-07

    Herein we report an efficient and recyclable system for tandem CO 2 capture and hydrogenation to methanol. After capture in an aqueous amine solution, CO 2 is hydrogenated in high yield to CH 3 OH (>90%) in a biphasic 2-MTHF/water system, which also allows for easy separation and recycling of the amine and catalyst for multiple reaction cycles. Between cycles, the produced methanol can be conveniently removed in vacuo. Employing this strategy, catalyst Ru-MACHO-BH and polyamine PEHA were recycled three times with 87% of the methanol producibility of the first cycle retained, along with 95% of catalyst activity after four cycles. CO 2 from dilute sources such as air can also be converted to CH 3 OH using this route. We postulate that the CO 2 capture and hydrogenation to methanol system presented here could be an important step toward the implementation of the carbon neutral methanol economy concept.

  17. Hydrogen absorption in Zr(Alsub(x)Bsub(1-x))2 (B = Fe, Co) Laves phase compounds

    International Nuclear Information System (INIS)

    Jacob, I.; Shaltiel, D.

    1978-01-01

    The hydrogen absorption capacity of the systems Zr(Alsub(x)Fesub(1-x)) 2 and Zr(Alsub(x)Cosub(1-x)) 2 (0 = 2 (A = V, Cr, Mn; B = Fe, Co; 0 =< x =< 1). The maximum hydrogen content in both systems is achieved for x approximately 2/12 at 40 atm and 80 K. Further increase of the Al content leads, however, to a steep decrease in the hydrogen capacity. This general behaviour is well described by a phenomenological model, recently proposed by the authors, thus supporting the importance of short-range neighbouring effects for the hydrogen absorption capacity. The influence of Al on the hydrogen sorption properties in different intermetallic compounds is discussed. (author)

  18. Hydrogen absorption mechanisms and hydrogen interactions - defects: implications to stress corrosion of nickel based alloys in pressurized water reactors primary water

    International Nuclear Information System (INIS)

    Jambon, F.

    2012-01-01

    Since the late 1960's, a special form of stress corrosion cracking (SCC) has been identified for Alloy 600 exposed to pressurized water reactors (PWR) primary water: intergranular cracks develop during the alloy exposure, leading, progressively, to the complete ruin of the structure, and to its replacement. The main goal of this study is therefore to evaluate in which proportions the hydrogen absorbed by the alloy during its exposure to the primary medium can be responsible for SCC crack initiation and propagation. This study is aimed at better understanding of the hydrogen absorption mechanism when a metallic surface is exposed to a passivating PWR primary medium. A second objective is to characterize the interactions of the absorbed hydrogen with the structural defects of the alloy (dislocations, vacancies...) and evaluate to what extent these interactions can have an embrittling effect in relation with SCC phenomenon. Alloy 600-like single-crystals were exposed to a simulated PWR medium where the hydrogen atoms of water or of the pressuring hydrogen gas were isotopically substituted with deuterium, used as a tracer. Secondary ion mass spectrometry depth-profiling of deuterium was performed to characterize the deuterium absorption and localization in the passivated alloy. The results show that the hydrogen absorption during the exposure of the alloy to primary water is associated with the water molecules dissociation during the oxide film build-up. In an other series of experiments, structural defects were created in recrystallized samples, and finely characterized by positron annihilation spectroscopy and transmission electron microscopy, before or after the introduction of cathodic hydrogen. These analyses exhibited a strong hydrogen/defects interaction, evidenced by their structural reorganization under hydrogenation (coalescence, migrations). However, thermal desorption spectroscopy analyses indicated that these interactions are transitory, and dependent on

  19. Hydrogen absorption and hydrogen-induced phase-separation in amorphous Zr[sub 50]Ni[sub 50-x]Cu[sub x] alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bakonyi, I. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Toth-Kadar, E. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Nagy, I. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Toth, J. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Tompa, K. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Lovas, A. (Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Solid State Physics); Cziraki, A. (Eoetvoes Univ., Budapest (Hungary). Inst. for Solid State Physics); Fogarassay, B. (Eoetvoes Univ., Budapest (Hungary). Inst. for Solid State Physics); Wiesinger, G. (Technische Univ., Vienna (Austria). Inst. fuer Experimentalphysik)

    1994-01-01

    The hydrogen absorption from the gas phase was investigated for melt-quenched Zr[sub 50]Ni[sub 50-x]Cu[sub x] (0[<=]x[<=]25) amorphous alloys by weighing, by thermoelectric power (TEP) and magnetization measurements aand by electron microscopy. A strongly nonmonotonous behaviour been observed, both as a function of the charging time and the Cu-content, for several materials characteristics and also for the nature of the hydrogen-induced phase-separation. (orig.)

  20. Hydrogen Absorption in Metal Thin Films and Heterostructures Investigated in Situ with Neutron and X-ray Scattering

    Directory of Open Access Journals (Sweden)

    Sara J. Callori

    2016-05-01

    Full Text Available Due to hydrogen possessing a relatively large neutron scattering length, hydrogen absorption and desorption behaviors in metal thin films can straightforwardly be investigated by neutron reflectometry. However, to further elucidate the chemical structure of the hydrogen absorbing materials, complementary techniques such as high resolution X-ray reflectometry and diffraction remain important too. Examples of work on such systems include Nb- and Pd-based multilayers, where Nb and Pd both have strong affinity to hydrogen. W/Nb and Fe/Nb multilayers were measured in situ with unpolarized and polarized neutron reflectometry under hydrogen gas charging conditions. The gas-pressure/hydrogen-concentration dependence, the hydrogen-induced macroscopic film swelling as well as the increase in crystal lattice plane distances of the films were determined. Ferromagnetic-Co/Pd multilayers were studied with polarized neutron reflectometry and in situ ferromagnetic resonance measurements to understand the effect of hydrogen absorption on the magnetic properties of the system. This electronic effect enables a novel approach for hydrogen sensing using a magnetic readout scheme.

  1. Vibration-rotational overtones absorption of solid hydrogens using optoacoustic spectroscopy technique

    International Nuclear Information System (INIS)

    Vieira, M.M.F.

    1985-01-01

    Vibrational-rotational overtones absorption solid hydrogens (H 2 , D 2 , HD) is studied using pulsed laser piezoeletric transducer (PULPIT) optoacoustic spectroscopy is studied. A general downward shift in energy from isolated molecular energies is observed. Studying normal-hydrogen it was observed that the phonon excitations associated with double-molecular transitions are predominantly transverse-optical phonons, whereas the excitations associated with single-molecular transitions are predominantly longitudinal - optical phonons. Multiplet structures were observed for certain double transitions in parahydrogen and orthodeuterium. The HD spectrum, besides presenting the sharp zero-phonon lines and the associated phonon side bands, like H 2 and D 2 , showed also two different features. This observation was common to all the transitions involving pure rotational excitation in H 2 and D 2 , which showed broad linewidths. This, together with some other facts (fluorescence lifetime *approx*10 5 sec; weak internal vibration and lattice coupling), led to the proposition of a mechanism for the fast nonradiative relaxation in solid hydrogens, implied from some observed experimental evidences. This relaxation, due to strong coupling, would happen in two steps: the internal vibration modes would relax to the rotational modes of the molecules, and then this rotational modes would relax to the lattice vibration modes. (Author) [pt

  2. 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.

  3. Study of neutral hydrogen transport in LHD core plasmas based on high dynamic-range Balmer-α spectroscopy

    International Nuclear Information System (INIS)

    Fujii, K.; Goto, M.; Morita, S.

    2014-10-01

    The radial distributions of the neutral hydrogen atom density and pressure in the Large Helical Device (LHD) were studied. The atom density distribution was determined from a detailed analysis of the intensity-calibrated Balmer-α line profile while the pressure distribution was obtained with a simple one-dimensional analytical model. We determined for the first time the atom density at the center of a fusion-oriented plasma, which is approximately three orders smaller than that at the edge. On the contrary, the atom pressure changes only a factor of 10 from the edge to core regions. (author)

  4. Ratio of neutral-current to charged-current cross sections for inclusive neutrino interactions in hydrogen

    International Nuclear Information System (INIS)

    Harris, F.A.; Berge, J.P.; Bogert, D.V.; Cence, R.J.; Coffin, T.C.; Cundy, D.C.; Diamond, R.N.; DiBianca, F.A.; French, H.T.; Hanft, R.; Kochowski, C.; Louis, W.C.; Lynch, G.R.; Malko, J.; Marriner, J.P.; Nezrick, F.A.; Parker, S.I.; Peters, M.W.; Peterson, V.Z.; Roe, B.P.; Ross, R.T.; Scott, W.G.; Seidl, A.A.; Smart, W.; Stenger, V.J.; Stevenson, M.L.; Vander Velde, J.C.

    1977-01-01

    The ratio of neutral-current to charged-current cross sections is determined from a sample of events obtained in an exposure of the Fermilab 15-ft hydrogen bubble chamber to a high-energy, horn-focused neutrino beam. For evens with three or more prongs and with visible hadron momentum above 10 GeV/c, the ratio is 0.40 +- 0.14. A Monte Carlo calculation assuming the Weinberg-Salam model is used to correct for excluded events, yielding R/sub NC/CC/ = 0.48 +- 0.17

  5. The kinetics of hydrogen absorption and desorption in LaNi@#5@#-@#x@#Al@#x@# slurries

    NARCIS (Netherlands)

    Snijder, E.D.; Snijder, E.D.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria

    1993-01-01

    The kinetics of hydrogen absorption and desorption in LaNi4.8Al0.2,LaNi4.9Al0.1 and LaNi5, suspended in cyclohexane and LaNi5 in ethanol have been investigated. The absorption process can be described in terms of mass transfer and reaction resistances in series. The rate-limiting steps for this

  6. Investigation of industrial compositions SONKOR as corrosion inhibitors of mild steel in neutral media containing hydrogen sulfide

    Directory of Open Access Journals (Sweden)

    A. V. Melnikova

    2015-10-01

    Full Text Available Electrochemical and corrosion behavior of mild steel in neutral media containing hydrogen sulfide has been investigated by weight-loss and electrochemical methods and protective effect of industrial compositions SONKOR has been determined. It has been shown that in 3%  NaCl compositions SONKOR have weak protective effect but it increases greatly in presence of hydrogen sulfide in the solution. At concentration of H2S = 0,6 gram per liter maximal protective effect has SONKOR 9801 (85,57% and SONKOR 9920А (81,97%. Inhibitors SONKOR 9021С (70,82%, 9510А(73,11% and 9701(67,87% show less protective effect.

  7. Free-free absorption coefficients and Gaunt factors for dense hydrogen-like stellar plasma

    Science.gov (United States)

    Srećković, V. A.; Sakan, N.; Šulić, D.; Jevremović, D.; Ignjatović, Lj M.; Dimitrijević, M. S.

    2018-03-01

    In this work, we present a study dedicated to determination of the inverse bremsstrahlung absorption coefficients and the corresponding Gaunt factor of dense hydrogen-like stellar-atmosphere plasmas where electron density and temperature change in a wide range. A method suitable for this wide range is suggested and applied to the inner layers of the solar atmosphere, as well as the plasmas of partially ionized layers of some other stellar atmospheres (for example, some DA and DB white dwarfs) where the electron densities vary from 1014 cm-3 to 1020 cm-3 and temperatures from 6000 K to 300 000 K in the wavelength region of 10 nm ≤ λ ≤ 3000 nm. The results of the calculations are illustrated by the corresponding figures and tables.

  8. Effect of thermal treatment on the electrochemical hydrogen absorption of ZrCrNi alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, F.C.; Peretti, H.A.; Corso, H.L [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Bariloche (Argentina); Visintin, A.; Real, S.G.; Castro, E.B.; Triaca, W.E. [Univ. Nacional de La Plata, La Plata (Argentina). Inst. de Investigaciones Fisiquimicas Teoricas y Aplicadas

    2006-07-01

    The catalytic effect of the secondary phases contained in a ZrCrNi alloy on its electrochemical properties was investigated. The purpose of the study was to improve the performance of Ni-MH battery electrodes. Four samples of the alloy were given annealing treatments at T=1250 K at variable times to obtain different concentrations of the secondary phases. Phase structure, morphology, and composition were studied using X-ray diffraction; radiation; scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) microanalysis. Results of the study were compatible with the presence of a major AB{sub 2} phase of C15 structure and the co-existence of C14 and C15 structures in both the as-melted and annealed alloys. The effect of the annealing in the ZrCrNi alloy resulted in a remarkable reduction of the discharge capacity and activation that was attributed to the dissolution of the secondary phases. The major catalytic effect was associated with the Zr{sub 8}Ni{sub 21} phase, by increasing the discharge capacity and favouring the activation. It was concluded that the presence of the catalytic phase in the alloy increased the hydrogen absorption capacity of the electrode due to an enhancement of the hydrogen production by electrolysis on the metal/catalytic phase and electrolyte interface. 6 refs., 1 fig.

  9. Changes in energy of three types of hydrogen bonds upon excitation of aminocoumarins determined from absorption solvatochromic experiments.

    Science.gov (United States)

    Krystkowiak, Ewa; Maciejewski, Andrzej

    2011-06-21

    Absorption spectra of 6-aminocoumarin (6AC) and 7-aminocoumarins (C120 and C151) were studied in polyfluorinated alcohols: (1,1,1,3,3,3-hexafluoroisopropanol (HFIP), 2,2,2-trifluoroethanol (TFE)), in water and in methanol, and compared to those taken in 1-chloro-n-alkanes. According to our results, the observed unusual blue-shift of a long-wavelength band in absorption spectra in strong protic solvents is direct evidence of significant weakening of a NH-O hydrogen bond. The results obtained for the aminocoumarins in HFIP, which in contrast to aliphatic alcohols does not form hydrogen bonds of the acceptor type, prove that the decrease in the energy of the NH-O hydrogen bond upon excitation to the lowest S(1)-LE state is significantly greater than the increase in the energy of hydrogen bonds made by the oxygen atom of carbonyl group OH-O. It is in contrast to theoretical calculations for C151 [Y. Liu, J. Ding, R. Liu, D. Shi and J. Sun, J. Photochem. Photobiol. A, 2009, 201, 203-207]. A comparison of the absorption spectra measured in DMSO and in 1-chloro-n-alkanes shows that the energy of two N-HO hydrogen bonds considerably increases as a result of excitation. These results are consistent with those of the theoretical calculations [Y. Liu, J. Ding, R. Liu, D. Shi and J. Sun, J. Photochem. Photobiol. A, 2009, 201, 203-207; P. Zhou, P. Song, J. Liu, K. Han and G. He, Phys. Chem. Chem. Phys., 2009, 11, 9440-9449]. In this study we applied the procedure proposed by us in J. Photochem. Photobiol. A, 2006, 184, 250-264 for the determination of changes in hydrogen bond energy as a result of electronic excitation based on analysis of the absorption spectra of the probe studied in the solvents interacting with it exclusively nonspecifically and in those forming hydrogen bonds with it.

  10. Neutralization and Acid Dissociation of Hydrogen Carbonate Ion: A Thermochemical Approach

    Science.gov (United States)

    Koga, Nobuyoshi; Shigedomi, Kana; Kimura, Tomoyasu; Tatsuoka, Tomoyuki; Mishima, Saki

    2013-01-01

    A laboratory inquiry into the thermochemical relationships in the reaction between aqueous solutions of NaHCO[subscript 3] and NaOH is described. The enthalpy change for this reaction, delta[subscript r]H, and that for neutralization of strong acid and NaOH(aq), delta[subscript n]H, are determined calorimetrically; the explanation for the…

  11. Hydrogen absorption kinetics and structural properties of Mg85Ni10Ca5 and Mg90Ni10

    International Nuclear Information System (INIS)

    Aoki, Masakazu; Saito, Katsushi; Towata, Shin-ichi

    2005-01-01

    Mg 85 Ni 10 Ca 5 and Mg 90 Ni 10 were prepared by melting mixtures of the elements in mild steel crucibles and pouring them into copper molds. Hydrogen absorption kinetics and structural properties of the alloys were characterized by the volumetric method using a Sievert's apparatus, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystallite size of Mg in Mg 85 Ni 10 Ca 5 , which is evaluated by XRD peak broadening, is about 50% smaller than that in Mg 90 Ni 10 . In addition, the nanometer-scale structure composed of Mg, Mg 2 Ni, Mg 2 Ca was observed in Mg 85 Ni 10 Ca 5 . Mg 85 Ni 10 Ca 5 shows better hydrogen absorption kinetics than Mg 90 Ni 10 in the temperature range of room temperature to 573 K. The better absorption kinetics of Mg 85 Ni 10 Ca 5 is mainly attributed to the nanometer-scale structure

  12. Modification of the electronic, magnetic and structural properties of Nb/Fe(110) multilayers via hydrogen absorption

    International Nuclear Information System (INIS)

    Rehm, Ch.; Fritzsche, H.; Maletta, H.; Klose, F.

    1999-01-01

    Complete text of publication follows. Hydrogen absorption in thin metal films may cause drastic changes of electronic, magnetic and structural properties. The effect of hydrogen loading from the gas phase on Nb/Fe multilayers was investigated (t Nb = 10 - 1000 A). The equilibrium hydrogen concentration in the Nb layers and the hydrogen-induced layer thickness expansion perpendicular to the film plane were determined as function of external hydrogen pressure by means of in-situ neutron reflectivity measurements. In-situ X-ray diffraction experiments performed on the same samples yielded the corresponding expansion of the out-of-plane Nb(110) interplanar spacing and the time-dependence of the charging and decharging process. It was found in all samples that the relative expansion of the Nb layers is considerably larger than the relative increase of the Nb(110) interplanar spacing. The magnetic properties were examined by means of in-situ neutron reflectivity, magnetoresistivity and SQUID measurements. We show that the magnetic exchange coupling between the Fe layers can reversibly be switched by hydrogen absorption/desorption due to changes in the electronic structure of the Nb spacer layers. (author)

  13. The corrosion rate and the hydrogen absorption behavior of titanium under reducing condition-III. Research document

    International Nuclear Information System (INIS)

    Suzuki, H.; Taniguchi, N.; Kawakami, S.

    2005-03-01

    Titanium is one of the candidate materials for overpacks as a high corrosion resistance metal. At the initial stage of repository, oxidizing condition will be given around the overpack because oxygen will be brought from the ground. The oxygen will be consumed by the reaction with impurities in buffer material or corrosion of overpack, and reducing condition will be achieved around the overpack. With the changing of redox condition, the water reduction becomes to dominate the cathodic reaction accompanying hydrogen generation. Crevice corrosion and hydrogen embrittlement are main causes of the damage of long term integrity of titanium overpack. However, it is not known about the corrosion resistance and hydrogen absorption behavior of titanium under reduction condition. In this study, the completely sealed ampoule test and the immersion test of titanium in aqueous solution and bentonite was carried out. In order to obtain reliable data about the hydrogen generation rate and the ratio of hydrogen absorption in titanium. From the result of 3 years immersion tests, corrosion rate of titanium were estimated to be in the order of 10 -2 ∼10 -1 μm/y in the aqueous solution, and 10 -3 ∼10 -2 μm/y in bentonite. This value is almost the same as the last report. Almost all the hydrogen generated by corrosion was absorbed in titanium in the immersion tests in completely sealed ampoule. In the examination that changed each parameter, it was suggested that the amount of the hydrogen absorption become 2∼3 times in 1M HCO 3- and pH13. (author)

  14. Renewable Hydrogen Carrier - Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    Science.gov (United States)

    2011-01-31

    The production of hydrogen by purple bacteria or microalgae are difficult to scale up due to low energy concentration insolation (e.g., ~200 W/m2...Cycle Assessment Of Biodiesel Production From Microalgae . Environ. Sci. Technol. 2009, 43, 6475–6481. 28. Logan, B.E.; Regan, J.M. Microbial fuel...sustainable production , high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density

  15. Cosmology on ultralarge scales with intensity mapping of the neutral hydrogen 21 cm emission: limits on primordial non-Gaussianity.

    Science.gov (United States)

    Camera, Stefano; Santos, Mário G; Ferreira, Pedro G; Ferramacho, Luís

    2013-10-25

    The large-scale structure of the Universe supplies crucial information about the physical processes at play at early times. Unresolved maps of the intensity of 21 cm emission from neutral hydrogen HI at redshifts z=/~1-5 are the best hope of accessing the ultralarge-scale information, directly related to the early Universe. A purpose-built HI intensity experiment may be used to detect the large scale effects of primordial non-Gaussianity, placing stringent bounds on different models of inflation. We argue that it may be possible to place tight constraints on the non-Gaussianity parameter f(NL), with an error close to σ(f(NL))~1.

  16. Observations of neutral hydrogen in radio-loud and interacting galaxies

    Science.gov (United States)

    Heckman, T. M.; Balick, B.; Van Breugel, W. J. W.; Miley, G. K.

    1983-01-01

    The results of a survey of H I in radio-loud and interacting galaxies is presented. Four cases of H I absorption and five of emission are reported. The interesting features found for individual galaxies are described, and the systematic properties are discussed. Column densities of absorbing gas generally exceed those expected for a 'Milky Way' H I disk by more than an order of magnitude. The absorbing gas must have a flattened, disklike morphology oriented roughly parallel to the optical disk of the galaxy. Turbulent noncircular gas motions are evidently present, which are shown to be almost certainly induced by galaxy-galaxy interactions. The set of galaxies in which H I absorption has been detected is dominated by morphologically peculiar objects. It is concluded that the detection of H I seen in absorption against a nuclear radio source permits direct determination of the sense of radial flow of extranuclear material, and is direct evidence that potential 'food' for a compact object in the nucleus exists in the galaxy.

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

    International Nuclear Information System (INIS)

    Eckstein, W.; Heifetz, D.B.

    1986-08-01

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

  18. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    International Nuclear Information System (INIS)

    Wachter, C.

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H α -spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H α -emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  19. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, C

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H{sub {alpha}}-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H{sub {alpha}}-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  20. Oxygen segregation and its impact on the absorption of hydrogen in vanadium; Einfluss der Sauerstoffsegregation auf die Absorption von Wasserstoff in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    The impact of the dissolved oxygen on the hydrogen absorption in vanadium was analysed with an UHV apparatus. The vanadium specimen with an oxygen content of 230 ppm was treated by a variety of heat treatments. The depth distributions of the induced concentrations of segregated oxygen in the specimen were analysed by SIMS. It was found that the amount of segregated oxygen increases with rising final temperature and tempering period. In a further experiment, the specimen was exposed after each segregation process to a H{sub 2}-pressure of 2.2 x 10{sup -4} Pa for a period of 1800 sec. The hydrogen amounts absorbed in the specimen were determined by thermal desorption mass spectrometry (TDMS). It was found that segregation of oxygen close to the surface of the specimen likewise hampers the absorption of hydrogen. (orig./CB) [Deutsch] Der Einfluss des im Volumen geloesten Sauerstoffs auf die Wasserstoff-Absorption in Vanadium wurde in einer UHV-Apparatur untersucht. Zunaechst wurde die V-Probe mit einem Sauerstoffgehalt von 230 ppm unterschiedlichen thermischen Behandlungen ausgesetzt. Die sich einstellenden Konzentrationstiefenverteilungen des an der Oberflaeche segregierten Sauerstoffs wurden anschliessend mit SIMS untersucht. Dabei nimmt die Menge des segregierten Sauerstoffs mit der Hoehe der Endtemperatur sowie der Temperzeit zu. In einem weiteren Experiment wurde die Probe nach jeder Segregationsprozedur fuer eine Zeit von 1800 sec einem H{sub 2}-Druck von 2.2 x 10{sup -4} Pa ausgesetzt. Die Mengen des dabei aufgenommenen Wasserstoffs wurden mit Hilfe der thermischen Desorptions-Massenspektrometrie TDMS bestimmt. Dabei zeigt sich, dass auch die Segregation von Sauerstoff im oberflaechennahen Bereich die Wasserstoffaufnahme in Vanadium behindert. (orig.)

  1. Energetic beams of negative and neutral hydrogen from intense laser plasma interaction

    Czech Academy of Sciences Publication Activity Database

    Abicht, F.; Prasad, R.; Borghesi, Marco; Priebe, G.; Braenzel, J.; Andreev, A.; Nickles, P.V.; Schnürer, M.; Jequier, S.; Revet, G.; Tikhonchuk, V.; Ter-Avetisyan, Sargis

    2013-01-01

    Roč. 103, č. 25 (2013), "253501-1"-"253501-5" ISSN 0003-6951 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 Keywords : charge-exchange * cross-sections * atomic-hydrogen * helium ions * gases * potassium * protons Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.515, year: 2013

  2. Total scattering cross sections and interatomic potentials for neutral hydrogen and helium on some noble gases

    International Nuclear Information System (INIS)

    Ruzic, D.N.; Cohen, S.A.

    1985-04-01

    Measurements of energy-dependent scattering cross sections for 30 to 1800 eV D incident on He, Ne, Ar, and Kr, and for 40 to 850 eV He incident on He, Ar, and Kr are presented. They are determined by using the charge-exchange efflux from the Princeton Large Torus tokamak as a source of D or He. These neutrals are passed through a gas-filled scattering cell and detected by a time-of-flight spectrometer. The cross section for scattering greater than the effective angle of the apparatus (approx. =20 mrad) is found by measuring the energy-dependent attenuation of D or He as a function of pressure in the scattering cell. The interatomic potential is extracted from the data

  3. Triplet excited electronic state switching induced by hydrogen bonding: A transient absorption spectroscopy and time-dependent DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kumar, Venkatraman; Ariese, Freek; Umapathy, Siva, E-mail: umapathy@ipc.iisc.ernet.in [Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012 (India)

    2016-03-21

    The solvent plays a decisive role in the photochemistry and photophysics of aromatic ketones. Xanthone (XT) is one such aromatic ketone and its triplet-triplet (T-T) absorption spectra show intriguing solvatochromic behavior. Also, the reactivity of XT towards H-atom abstraction shows an unprecedented decrease in protic solvents relative to aprotic solvents. Therefore, a comprehensive solvatochromic analysis of the triplet-triplet absorption spectra of XT was carried out in conjunction with time dependent density functional theory using the ad hoc explicit solvent model approach. A detailed solvatochromic analysis of the T-T absorption bands of XT suggests that the hydrogen bonding interactions are different in the corresponding triplet excited states. Furthermore, the contributions of non-specific and hydrogen bonding interactions towards differential solvation of the triplet states in protic solvents were found to be of equal magnitude. The frontier molecular orbital and electron density difference analysis of the T{sub 1} and T{sub 2} states of XT indicates that the charge redistribution in these states leads to intermolecular hydrogen bond strengthening and weakening, respectively, relative to the S{sub 0} state. This is further supported by the vertical excitation energy calculations of the XT-methanol supra-molecular complex. The intermolecular hydrogen bonding potential energy curves obtained for this complex in the S{sub 0}, T{sub 1}, and T{sub 2} states support the model. In summary, we propose that the different hydrogen bonding mechanisms exhibited by the two lowest triplet excited states of XT result in a decreasing role of the nπ{sup ∗} triplet state, and are thus responsible for its reduced reactivity towards H-atom abstraction in protic solvents.

  4. The kinetics of Cr layer coated on TiNi films for hydrogen absorption

    Indian Academy of Sciences (India)

    The nickel titanium alloy. Ti2Ni and TiNi have been used by [1–3] as electrode materials for reversible hy- drogen electrode in nickel hydrogen system. The reversible hydrogen electrodes of this type have been .... The resistance of thin films increases on exposure to hydrogen in vacuum chamber as reported by Adachi et al ...

  5. Extended Neutral Hydrogen in the Aligned Shell Galaxies Arp 230 and MCG -5-7-1 : Formation of Disks in Merging Galaxies?

    NARCIS (Netherlands)

    Schiminovich, David; van Gorkom, J. H.; van der Hulst, J. M.

    As part of an ongoing study of the neutral hydrogen (H I) morphology and kinematics of "shell" elliptical galaxies, we present Very Large Array observations of two shell galaxies with aligned shells, Arp 230 and MCG -5-7-1. Our data provide the first Hi images of Arp 230 and deeper images of MCG

  6. Gastrointestinal Inhibition of Sodium-Hydrogen Exchanger 3 Reduces Phosphorus Absorption and Protects against Vascular Calcification in CKD.

    Science.gov (United States)

    Labonté, Eric D; Carreras, Christopher W; Leadbetter, Michael R; Kozuka, Kenji; Kohler, Jill; Koo-McCoy, Samantha; He, Limin; Dy, Edward; Black, Deborah; Zhong, Ziyang; Langsetmo, Ingrid; Spencer, Andrew G; Bell, Noah; Deshpande, Desiree; Navre, Marc; Lewis, Jason G; Jacobs, Jeffrey W; Charmot, Dominique

    2015-05-01

    In CKD, phosphate retention arising from diminished GFR is a key early step in a pathologic cascade leading to hyperthyroidism, metabolic bone disease, vascular calcification, and cardiovascular mortality. Tenapanor, a minimally systemically available inhibitor of the intestinal sodium-hydrogen exchanger 3, is being evaluated in clinical trials for its potential to (1) lower gastrointestinal sodium absorption, (2) improve fluid overload-related symptoms, such as hypertension and proteinuria, in patients with CKD, and (3) reduce interdialytic weight gain and intradialytic hypotension in ESRD. Here, we report the effects of tenapanor on dietary phosphorous absorption. Oral administration of tenapanor or other intestinal sodium-hydrogen exchanger 3 inhibitors increased fecal phosphorus, decreased urine phosphorus excretion, and reduced [(33)P]orthophosphate uptake in rats. In a rat model of CKD and vascular calcification, tenapanor reduced sodium and phosphorus absorption and significantly decreased ectopic calcification, serum creatinine and serum phosphorus levels, circulating phosphaturic hormone fibroblast growth factor-23 levels, and heart mass. These results indicate that tenapanor is an effective inhibitor of dietary phosphorus absorption and suggest a new approach to phosphate management in renal disease and associated mineral disorders. Copyright © 2015 by the American Society of Nephrology.

  7. Photocatalytic hydrogen evolution from carbon-neutral oxalate with 2-phenyl-4-(1-naphthyl)quinolinium ion and metal nanoparticles.

    Science.gov (United States)

    Yamada, Yusuke; Miyahigashi, Takamitsu; Ohkubo, Kei; Fukuzumi, Shunichi

    2012-08-14

    Photocatalytic hydrogen evolution has been made possible by using oxalate as a carbon-neutral electron source, metal nanoparticles as hydrogen-evolution catalysts and the 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh(+)-NA), which forms the long-lived electron-transfer state upon photoexcitation, as a photocatalyst. The hydrogen evolution was conducted in a deaerated mixed solution of an aqueous buffer and acetonitrile (MeCN) [1:1 (v/v)] by photoirradiation (λ > 340 nm). The gas evolved during the photocatalytic reaction contained H(2) and CO(2) in a molar ratio of 1:2, indicating that oxalate acts as a two-electron donor. The hydrogen yield based on the amount of oxalate reached more than 80% under pH conditions higher than 6. Ni and Ru nanoparticles as well as Pt nanoparticles act as efficient hydrogen-evolution catalysts in the photocatalytic hydrogen evolution. The photocatalyst for hydrogen evolution can be used several times without significant deactivation of the catalytic activity. Nanosecond laser flash photolysis measurements have revealed that electron transfer from oxalate to the photogenerated QuPh˙-NA˙(+), which forms a π-dimer radical cation with QuPh(+)-NA [(QuPh˙-NA˙(+))(QuPh(+)-NA)], occurs followed by subsequent electron transfer from QuPh˙-NA to the hydrogen-evolution catalyst in the photocatalytic hydrogen evolution. Oxalate acts as an efficient electron source under a wide range of reaction conditions.

  8. Observation and Interpretation of Energetic Neutral Hydrogen Atoms from the December 5, 2006 Solar Event

    Science.gov (United States)

    Mewaldt, R. A.; Leske, R. A.; Stone, E. C.; Barghouty, A. F.; Shih, A. Y.; von Rosenvinge, T. T.; Labrador, A. W.; Cohen, C. M. S.; Cummings, A. C.; Cummings, A. C.

    2009-01-01

    We report the first observations of energetic neutral atoms (ENAs) from a solar flare/coronal mass ejection event. The observations were made during the December 5, 2006 X9 solar flare, located at E79, by the Low Energy Telescopes (LETs) on the STEREO A and B spacecraft. Within 1-2 hours of the flare onset, both LETs observed a sudden burst of 1.6 to 15 MeV protons arriving hours before the onset of the main solar energetic particle (SEP) event at Earth. More than 70% of these particles arrived from a longitude within +-10 degrees of the Sun. The derived emission profile at the Sun lasted for more than an hour and had a profile remarkably similar to the GOES soft X-ray profile. The observed arrival directions and energy spectrum argue strongly that the particle events atoms that were stripped of their electrons upon entering the LET sensor. To our knowledge, this is the first reported observation of ENA emission from a solar flare/coronal mass ejection. We discuss possible origins for the production of ENAs in solar events, including charge-transfer reactions involving both flare and shock-accelerated protons. Assuming isotropic emission, we find that 2 x 10E28 ENAs escaped from the Sun in the upper hemisphere. Based on the 2.2 MeV gamma-ray emission observed by RHESSI in this event, and using measured and theoretical cross sections, we estimate that 3 x 10E31 ENAs with 1.8 - 5 MeV could be produced by protons accelerated in the flare. CME-driven shock acceleration is also a possible ENA source, but unfortunately there were no CME observations available from this event. Taking into account ENA losses, we conclude that the observed ENAs were most likely produced in the high corona at heliocentric distances 1.6 solar radii.

  9. Infrared Spectra of Protonated Pyrene and Its Neutral Counterpart in Solid para-Hydrogen.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Yu-Jong; Lee, Yuan-Pern

    2013-06-20

    Protonated polycyclic aromatic hydrocarbons (H(+)PAHs) have been reported to have infrared (IR) bands at wavenumbers near those of unidentified infrared (UIR) emission bands from interstellar objects. We produced 1-C16H11(+) and 1-C16H11 upon electron bombardment during matrix deposition of p-H2 containing pyrene (C16H10) in a small proportion. Intensities of absorption features of 1-C16H11(+) decreased after the matrix was maintained in darkness or irradiated with light at 365 nm, whereas those of 1-C16H11 increased. The observed line wavenumbers and relative intensities of 1-C16H11(+) and 1-C16H11 agree satisfactorily with the scaled vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. Our method, being relatively clean with negligible fragmentation, is applicable to larger H(+)PAH; it has the advantages of producing excellent IR spectra covering a broad spectral range with narrow lines and accurate intensities, so that structural identification among various isomers is feasible.

  10. 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

  11. Calculation of neutral beam deposition accounting for excited states

    International Nuclear Information System (INIS)

    Gianakon, T.A.

    1992-09-01

    Large-scale neutral-beam auxillary heating of plasmas has led to new plasma operational regimes which are often dominated by fast ions injected via the absorption of an energetic beam of hydrogen neutrals. An accurate simulation of the slowing down and transport of these fast ions requires an intimate knowledge of the hydrogenic neutral deposition on each flux surface of the plasma. As a refinement to the present generation of transport codes, which base their beam deposition on ground-state reaction rates, a new set of routines, based on the excited states of hydrogen, is presented as mechanism for computing the attenuation and deposition of a beam of energetic neutrals. Additionally, the numerical formulations for the underlying atomic physics for hydrogen impacting on the constiuent plasma species is developed and compiled as a numerical database. Sample results based on this excited state model are compared with the ground-state model for simple plasma configurations

  12. The effects of the small-scale DM power on the cosmological neutral hydrogen (HI) distribution at high redshifts

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Abir; Sethi, Shiv K. [Department of Astronomy And Astrophysics, Raman Research Institue, C.V. Raman Avenue, Bangalore (India); Mondal, Rajesh; Bharadwaj, Somnath [Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Das, Subinoy [Indian Institue of Astrophysics, 100 Feet Rd, Madiwala, Bangalore (India); Marsh, David J.E., E-mail: abir@rri.res.in, E-mail: rm@phy.iitkgp.ernet.in, E-mail: subinoy@iiap.res.in, E-mail: sethi@rri.res.in, E-mail: somnath@phy.iitkgp.ernet.in, E-mail: david.marsh@kcl.ac.uk [Department of Physics, King' s College London, Strand, London, WC2R 2LS (United Kingdom)

    2016-04-01

    The particle nature of dark matter remains a mystery. In this paper, we consider two dark matter models—Late Forming Dark Matter (LFDM) and Ultra-Light Axion (ULA) models—where the matter power spectra show novel effects on small scales. The high redshift universe offers a powerful probe of their parameters. In particular, we study two cosmological observables: the neutral hydrogen (HI) redshifted 21-cm signal from the epoch of reionization, and the evolution of the collapsed fraction of HI in the redshift range 2 < z < 5. We model the theoretical predictions of the models using CDM-like N-body simulations with modified initial conditions, and generate reionization fields using an excursion set model. The N-body approximation is valid on the length and halo mass scales studied. We show that LFDM and ULA models predict an increase in the HI power spectrum from the epoch of reionization by a factor between 2–10 for a range of scales 0.1 < k < 4 Mpc{sup −1}. Assuming a fiducial model where a neutral hydrogen fraction x-bar {sub HI} = 0.5 must be achieved by z = 8, the reionization process allows us to put approximate bounds on the redshift of dark matter formation z{sub f} > 4 × 10{sup 5} (for LFDM) and the axion mass m{sub a} > 2.6 × 10{sup −23} eV (for ULA). The comparison of the collapsed mass fraction inferred from damped Lyman-α observations to the theoretical predictions of our models lead to the weaker bounds: z{sub f} > 2 × 10{sup 5} and m{sub a} > 10{sup −23} eV. These bounds are consistent with other constraints in the literature using different observables; we briefly discuss how these bounds compare with possible constraints from the observation of luminosity function of galaxies at high redshifts. In the case of ULAs, these constraints are also consistent with a solution to the cusp-core problem of CDM.

  13. A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

    International Nuclear Information System (INIS)

    Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

    2016-01-01

    The solid-state pH electrode has the potential possibility to be used in many extreme situations with satisfactory accuracy and low cost. But its performance is affected by the solid electrolyte, preparation process, and the structure of the sensitive membrane, etc. In this work, the relationships between these factors and the characteristic of the prepared electrode were verified by controlling the preparation conditions with a variety of electrochemical methods. Firstly, the solid electrolyte poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) was electrochemically deposited on the screen-printed carbon electrode (SPCE) substrate by a potentiostatic method in an aqueous solution containing 0.01 M 3,4-ethylenedioxythiophene (EDOT) and 0.1 M polystyrene sulfonic (PSS) acid as the supporting electrolyte. The PEDOT films were then characterized by cyclic voltammetry (CV) in the 0.1 M NaNO3 aqueous solution in order to obtain the optimized polymerization potential and charges where the PEDOT film would have a higher redox capacitance. Finally, the pH electrode was prepared by coating the SPCE/PEDOT(PSS) with a plasticized polyvinyl chloride (PVC) membrane containing tridodecylamine as hydrogen ionophore manually, and experiments were carried out to study the effect of the usage of PVC per square millimeter on the response time and stability of the electrode to optimize the PVC film thickness. The potentiometric response of the pH electrode was studied in the buffer solutions with pH ranging from 5.00 to 10.81 by the open-circuit potential (OCP) method. Experimental results show that the sensitivity of the electrode is  −55.7  ±  0.5 mV pH −1 ( r 2   >  0.9980) at room temperature (24  ±  1 °C) with pH ranging from 2.00–10.50, approximating to the theoretical nernstian slope (−59.16 mV pH −1 ),and the response time was less than 10 s. Moreover, it has low impedance, high accuracy and potential stability

  14. A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

    Science.gov (United States)

    Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

    2016-10-01

    The solid-state pH electrode has the potential possibility to be used in many extreme situations with satisfactory accuracy and low cost. But its performance is affected by the solid electrolyte, preparation process, and the structure of the sensitive membrane, etc. In this work, the relationships between these factors and the characteristic of the prepared electrode were verified by controlling the preparation conditions with a variety of electrochemical methods. Firstly, the solid electrolyte poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) was electrochemically deposited on the screen-printed carbon electrode (SPCE) substrate by a potentiostatic method in an aqueous solution containing 0.01 M 3,4-ethylenedioxythiophene (EDOT) and 0.1 M polystyrene sulfonic (PSS) acid as the supporting electrolyte. The PEDOT films were then characterized by cyclic voltammetry (CV) in the 0.1 M NaNO3 aqueous solution in order to obtain the optimized polymerization potential and charges where the PEDOT film would have a higher redox capacitance. Finally, the pH electrode was prepared by coating the SPCE/PEDOT(PSS) with a plasticized polyvinyl chloride (PVC) membrane containing tridodecylamine as hydrogen ionophore manually, and experiments were carried out to study the effect of the usage of PVC per square millimeter on the response time and stability of the electrode to optimize the PVC film thickness. The potentiometric response of the pH electrode was studied in the buffer solutions with pH ranging from 5.00 to 10.81 by the open-circuit potential (OCP) method. Experimental results show that the sensitivity of the electrode is  -55.7  ±  0.5 mV pH-1 (r 2  >  0.9980) at room temperature (24  ±  1 °C) with pH ranging from 2.00-10.50, approximating to the theoretical nernstian slope (-59.16 mV pH-1),and the response time was less than 10 s. Moreover, it has low impedance, high accuracy and potential stability as well as some

  15. Ab-initio calculations of the hydrogen-uranium system: Surface phenomena, absorption, transport and trapping

    International Nuclear Information System (INIS)

    Taylor, Christopher D.; Scott Lillard, R.

    2009-01-01

    Density functional theory was applied to the initial steps of uranium hydriding: surface phenomena, absorption, bulk transport and trapping. H adsorbs exothermically to the (0 0 1) surface, yet H absorption into the bulk is endothermic, with off-center octahedral absorption having the lowest absorption energy of 0.39 eV, relative to molecular H 2 . H absorption in interstitial sites causes a local softening of the bulk modulus. Diffusion of H in unstrained α-U has a barrier of 0.6 eV. The energy of H absorption adjacent to the chemical impurities C, S, Si was lowered by an amount proportional to the size of the impurity atom, and the resulting lattice strain Si > S > C. Thus, impurities may promote hydriding by providing surfaces or prestrained zones for H uptake.

  16. Determination of concentration and molar absorptivity of hypochlorous acid and hypobromous acid species by hydrogen peroxide titration

    Science.gov (United States)

    Uehara, H.; Arakaki, T.

    2017-12-01

    Hypochlorous acid and hypobromous acid (abbreviated as "HypoX acids") are the main ingredients of bleaching and bactericides. The HypoX acids change their chemical forms depending on environmental factors such as pH and various chemical reactions. For example, it has been reported that hypobromite ion in water changes to carcinogenic bromate by photochemical reaction with ultraviolet light. In this study, concentrations of HypoX acids were determined by UV-VIS absorbance measurement utilizing the fact that HypoX acids react with hydrogen peroxide and do not co-exist in the solution. The method for determining the concentration by titration with hydrogen peroxide can be carried out simpler and more efficiently than the DPD method or the current titration method generally used for chlorine concentration measurement. Molar absorptivity between 250 - 500 nm of HypoX acids, including their conjugate base species, was determined by solving theoretical acid-base formula including molar fraction of each chemical species at various pHs. Molar absorptivity of OCl- and OBr- between 250 - 500 nm was determined based on the concentrations obtained from titration with hydrogen peroxide and absorbance at pH > 10, where OCl- and OBr- dominate. Furthermore, the HypoX acids solutions were irradiated with a solar simulator, and the photolysis rate constants were obtained. Based on those values, the half-lives were calculated and the behavior of HypoX acids in the environment was elucidated.

  17. The effects of the small-scale DM power on the cosmological neutral hydrogen (HI) distribution at high redshifts

    Science.gov (United States)

    Sarkar, Abir; Mondal, Rajesh; Das, Subinoy; Sethi, Shiv. K.; Bharadwaj, Somnath; Marsh, David J. E.

    2016-04-01

    The particle nature of dark matter remains a mystery. In this paper, we consider two dark matter models—Late Forming Dark Matter (LFDM) and Ultra-Light Axion (ULA) models—where the matter power spectra show novel effects on small scales. The high redshift universe offers a powerful probe of their parameters. In particular, we study two cosmological observables: the neutral hydrogen (HI) redshifted 21-cm signal from the epoch of reionization, and the evolution of the collapsed fraction of HI in the redshift range 2 4 × 105 (for LFDM) and the axion mass ma > 2.6 × 10-23 eV (for ULA). The comparison of the collapsed mass fraction inferred from damped Lyman-α observations to the theoretical predictions of our models lead to the weaker bounds: zf > 2 × 105 and ma > 10-23 eV. These bounds are consistent with other constraints in the literature using different observables; we briefly discuss how these bounds compare with possible constraints from the observation of luminosity function of galaxies at high redshifts. In the case of ULAs, these constraints are also consistent with a solution to the cusp-core problem of CDM.

  18. Spatial Variations of Turbulent Properties of Neutral Hydrogen Gas in the Small Magellanic Cloud Using Structure-function Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nestingen-Palm, David; Stanimirović, Snežana; González-Casanova, Diego F.; Babler, Brian [Astronomy Department, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706-1582 (United States); Jameson, Katherine; Bolatto, Alberto, E-mail: sstanimi@astro.wisc.edu [Astronomy Department and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2017-08-10

    We investigate spatial variations of turbulent properties in the Small Magellanic Cloud (SMC) by using neutral hydrogen (H i) observations. With the goal of testing the importance of stellar feedback on H i turbulence, we define central and outer SMC regions based on the star formation rate (SFR) surface density, as well as the H i integrated intensity. We use the structure function and the velocity channel analysis to calculate the power-law index ( γ ) for both underlying density and velocity fields in these regions. In all cases, our results show essentially no difference in γ between the central and outer regions. This suggests that H i turbulent properties are surprisingly homogeneous across the SMC when probed at a resolution of 30 pc. Contrary to recent suggestions from numerical simulations, we do not find a significant change in γ due to stellar feedback as traced by the SFR surface density. This could be due to the stellar feedback being widespread over the whole of the SMC, but more likely due to a large-scale gravitational driving of turbulence. We show that the lack of difference between central and outer SMC regions cannot be explained by the high optical depth H I.

  19. Detection of hydrogen peroxide based on long-path absorption spectroscopy using a CW EC-QCL

    Science.gov (United States)

    Sanchez, N. P.; Yu, Y.; Dong, L.; Griffin, R.; Tittel, F. K.

    2016-02-01

    A sensor system based on a CW EC-QCL (mode-hop-free range 1225-1285 cm-1) coupled with long-path absorption spectroscopy was developed for the monitoring of gas-phase hydrogen peroxide (H2O2) using an interference-free absorption line located at 1234.055 cm-1. Wavelength modulation spectroscopy (WMS) with second harmonic detection was implemented for data processing. Optimum levels of pressure and modulation amplitude of the sensor system led to a minimum detection limit (MDL) of 25 ppb using an integration time of 280 sec. The selected absorption line for H2O2, which exhibits no interference from H2O, makes this sensor system suitable for sensitive and selective monitoring of H2O2 levels in decontamination and sterilization processes based on Vapor Phase Hydrogen Peroxide (VPHP) units, in which a mixture of H2O and H2O2 is generated. Furthermore, continuous realtime monitoring of H2O2 concentrations in industrial facilities employing this species can be achieved with this sensing system in order to evaluate average permissible exposure levels (PELs) and potential exceedances of guidelines established by the US Occupational Safety and Health Administration for H2O2.

  20. Hydrogen absorption and its effect on magnetic properties of Nd2Fe14B

    Science.gov (United States)

    Bezdushnyi, R.; Damianova, R.; Tereshina, I. S.; Pankratov, N. Yu.; Nikitin, S. A.

    2018-05-01

    Magnetic properties of hydrides of the intermetallic compound Nd2Fe14BHx are investigated in the temperature range covering the Curie temperatures (TC) of the compounds (up to 670 K). The temperature dependencies of magnetization are measured under continuous control of hydrogen content in the investigated samples. The dependencies of Curie and spin-reorientation transition (TSR) temperatures on the hydrogen concentration are studied in detail. The dependence of hydrogen concentration on pressure at a constant temperature (near TC) and on the temperature at various pressures are obtained. We attempted to estimate the contributions of the unit cell volume increase upon hydrogenation and the electronic structure change in the variation of TC of the hydrogenated Nd2Fe14 B .

  1. In-situ neutron investigation of hydrogen absorption kinetics in La(FexSi1-x)13 magnetocaloric alloys for room-temperature refrigeration application

    Science.gov (United States)

    Hai, Xueying; Mayer, Charlotte; Colin, Claire V.; Miraglia, Salvatore

    2016-02-01

    Promising magnetocaloric material La(Fe,Si)13 with a first-order magnetic transition has been widely investigated. The observed instability of hydrogen in the material is detrimental for its industrial upscale and a better control of the hydrogen absorption/desorption is necessary to optimize its application potential. In this article, the hydrogen absorption kinetics is studied through an in-situ neutron diffraction experiment. The results allow us to have an inside look at the structure "breathing" to accommodate the interstitial atoms and compare the effect of hydrides with carbohydrides.

  2. Infrared absorption study of hydrogen incorporation in thick nanocrystalline diamond films

    International Nuclear Information System (INIS)

    Tang, C.J.; Neves, A.J.; Carmo, M.C.

    2005-01-01

    We present an infrared (IR) optical absorbance study of hydrogen incorporation in nanocrystalline diamond films. The thick nanocrystalline diamond films were synthesized by microwave plasma-assisted chemical vapor deposition and a high growth rate about 3.0 μm/h was achieved. The morphology, phase quality, and hydrogen incorporation were assessed by means of scanning electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Large amount of hydrogen bonded to nanocrystalline diamond is clearly evidenced by the huge CH stretching band in the FTIR spectrum. The mechanism of hydrogen incorporation is discussed in light of the growth mechanism of nanocrystalline diamond. This suggests the potential of nanocrystalline diamond for IR electro-optical device applications

  3. Hydrogen absorption in RE.sub.2./sub.T.sub.2./sub.In compounds

    Czech Academy of Sciences Publication Activity Database

    Mašková, S.; Kolomiets, A.; Havela, L.; Andreev, Alexander V.; Svoboda, P.; Nakotte, H.; Černý, R.

    2013-01-01

    Roč. 580, DEC (2013), S105-S108 ISSN 0925-8388 Institutional support: RVO:68378271 Keywords : antiferromagnetism * frustration * hydrogen Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.726, year: 2013

  4. ASSOCIATIONS BETWEEN SMALL-SCALE STRUCTURE IN LOCAL GALACTIC NEUTRAL HYDROGEN AND IN THE COSMIC MICROWAVE BACKGROUND OBSERVED BY PLANCK

    International Nuclear Information System (INIS)

    Verschuur, Gerrit L.

    2015-01-01

    High-resolution galactic neutral hydrogen (HI) data obtained with the Green Bank Telescope (GBT) over 56 square degrees of sky around l = 132°, b = 25° are compared with small-scale structure in the Cosmic Microwave Background observed by PLANCK, specifically at 143 and 857 GHz, as well as with 100 μm observations from the IRIS survey. The analysis uses data in 13 2° × 2° sub-areas found in the IRSA database at IPAC. The results confirm what has been reported previously; nearby galactic HI features and high-frequency continuum sources believed to be cosmological are in fact clearly associated. While several attempts strongly suggest that the associations are statistically significant, the key to understanding the phenomenon lies in the fact that in any given area HI is associated with cirrus dust at certain HI velocities and with 143 GHz features at different velocities. At the same time, for the 13 sub-areas studied, there is very little overlap between the dust and 143 GHz features. The data do not imply that the HI itself gives rise to the high-frequency continuum emission. Rather, they appear to indicate undiagnosed brightness enhancements indirectly associated with the HI. If low density interstellar electrons concentrated into clumps, or observed in directions where their integrated line-of-sight column densities are greater than the background in a manner similar to the phenomena that give rise to structure in diffuse HI structure, they will profoundly affect attempts to create a foreground electron mask used for processing PLANCK as well as WMAP data

  5. DFT calculation of geometrical structure and electronic absorption spectra for neutral, mono-, and diprotonated forms of Risperidone (Risperdal)

    Science.gov (United States)

    Alparone, A.

    2012-09-01

    Vertical electronic transitions to singlet valence states of an antipsychotic drug, Risperidone (Risperdal), in its neutral, mono-, and diprotonated forms have been calculated within the time-dependent density functional theory using the PBE0 hybrid functional with the 6-31+G* basis set. The results of the computations show that the lowest-energy allowed π-π* electronic excitation is affected by protonation effects, the spectral shifts of this transition being potentially useful to individuate the different forms of risperidone

  6. Hydrogen production by the high temperature combination of the water gas shift and CO{sub 2} absorption reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bretado, M.A.E.; Vigil, M.D.D.; Gutierrez, J.S.; Ortiz, A.L.; Collins-Martinez, V. [Centro de Investigacion en Materiales Avanzados, Chihuahua, Chih (Mexico). Dept. de Quimica de Materiales

    2009-01-15

    Hydrogen is an important raw material for the chemical and petroleum industry. An important research field has surfaced, dealing with the production of high purity hydrogen for power generation purposes through fuel cells. Industrial technologies for hydrogen production are based on the use of fossil fuels, with catalytic steam methane reforming being the most important process together with partial oxidation of hydrocarbons and the integrated combined coal gasification cycle. Hydrogen production through the water gas shift (WGS) reaction requires two consecutive catalytic steps followed by carbon dioxide (CO{sub 2}) separation. However, combination of the WGS reaction and CO{sub 2} capture by a solid absorbent opens the opportunity to produce high purity hydrogen in one single step called absorption enhanced WGS or AEWGS. In theory, this process would not require a catalyst. This paper presented an experimental study of AEWGS using a quartz-made fixed bed reactor. The CO{sub 2} absorbents tested in this study were calcined dolomite, (CaOMgO) and sodium zirconate (Na{sub 2}ZrO{sub 3}). The paper described the experimental study, with particular reference to the thermodynamic analysis that determined the equilibrium conditions of the systems CO/H{sub 2}O (WGS) and CO/absorbent/H{sub 2} (AEWGS); synthesis and characterization; and the fixed bed reaction system. Results were determined by X-ray diffraction, BET surface area and crystallite size, and reaction evaluation. It was concluded that at reaction conditions, dolomite can efficiently remove CO{sub 2} at partial pressures three times lower than with the use of Na{sub 2}ZrO{sub 3} as absorbent. 24 refs., 1 tab., 6 figs.

  7. Infrared absorption spectra of t-HNOH radicals generated on VUV irradiation of NO in solid hydrogen.

    Science.gov (United States)

    Wu, Yu-Jong; Lin, Meng-Yeh; Hsu, Sheng-Chuan; Cheng, Bing-Ming

    2009-04-14

    Photoproduct signature: Irradiation of solid hydrogen near 3 K containing NO with vacuum-UV light from synchrotron radiation yields new infrared absorption lines at 1241.7, 1063.6 and 726.2 cm(-1) (see figure). These new lines are assigned to vibrational modes of t-HNOH. This photoproduct is formed from electronically excited NO reacting with neighboring hydrogen in the solid sample.Irradiation of solid H(2) near 3 K containing NO with vacuum-ultraviolet light from a synchrotron yields new infrared absorption lines at 1241.7, 1063.6 and 726.2 cm(-1). The structures of four possible structural isomers: H(2)NO, t-HNOH, c-HNOH and NOH(2), their vibrational wavenumbers, IR intensities and D-isotopic shifts are calculated with density-functional theory according to B3LYP and PW91PW91/aug-cc-pVTZ methods. Based on the results of those calculations and of experiments with deuterium labeling, we assign the new lines to nu(4) (cis bending), nu(5) (N==O stretching) and nu(6) (out-of-plane deformation) modes, respectively, of t-HNOH. This photoproduct is formed through reaction of electronically excited NO with neighboring H(2) in the solid sample.

  8. Catalytic effect of additional metallic phases on the hydrogen absorption behavior of a Zr-Based alloy

    International Nuclear Information System (INIS)

    Ruiz, F; Peretti, H; Castro, E; Real, S; Visitin, A; Triaca, W

    2005-01-01

    The electrochemical hydrogen absorption of electrodes containing Zr 0 .9Ti 0 .1(Ni 0 .5Mn 0 .25Cr 0 .20V 0 .05) 2 is studied in alkaline media by monitoring the activation and discharge capacity along charge-discharge cycling.The considered alloy is tested in both as melted and annealed condition in order to investigate the catalytic effect of small amounts of micro segregated secondary phases of the Zr-Ni system. Since these catalytic phases are only present in the as melted alloys, tests are also carried out using a composite material elaborated from powders of the annealed alloy with the addition of 18 wt.% of the suspected catalytic phases, melted separately.The hydrogen absorption-desorption behavior for the different cases is discussed and correlated with the metallurgical characterization of the materials.The catalytic effects are studied employing cyclic voltammetry and electrochemical impedance techniques. The results are analyzed in terms of a developed physicochemical model

  9. Hydrogen Absorption Induced Slow Crack Growth in Austenitic Stainless Steels for Petrochemical Pressure Vessel Industries

    Directory of Open Access Journals (Sweden)

    Ronnie Rusli

    2011-05-01

    Full Text Available Type 304Land type 309 austenitic stainless steels were tested either by exposed to gaseous hydrogen or undergoing polarized cathodic charging. Slow crack growth by straining was observed in type 304L, and the formation of α‘ martensite was indicated to be precursor for such cracking. Gross plastic deformation was observed at the tip of the notch, and a single crack grew slowly from this region in a direction approximately perpendicular to the tensile axis. Martensite formation is not a necessary condition for hydrogen embrittlement in the austenitic phase.

  10. Investigation of neutral and ion dynamics in a HiPIMS plasma by tunable laser diode absorption spectroscopy (TDLAS)

    Science.gov (United States)

    Preissing, Patrick; Hecimovic, Ante; von Keudell, Achim

    2016-09-01

    High power impulse magnetron sputtering (HiPIMS) discharges are known for complex plasma interactions, and complex temporal and spatial dynamics. Spatial and temporal dynamic of argon metastable (Arm), Ti atom (Ti0) and Ti ion (Ti+) density and temperature is studied by an extended tunable diode laser absorption spectroscopy setup (TDLAS) during a HiPIMS pulse. The TDLAS setup used a beam expander in combination with a 6 photo diode array to simultaneously measure spatial (resolution 5 mm) and time resolved absorption profiles of an Arm, Ti0 and Ti+ transition. This in combination with moving the magnetron in axial direction gives a complete 2D map of the density evolution. Temporal resolution of 400 ns was achieved by recording the photo diode signal on the National Instruments card. Final results allowed to investigate temporal evolution of the observed species in the volume between the target and the substrate.

  11. Effect of the hydrogen absorption on the positioning of the plastic deformation of a stainless steel-316L

    International Nuclear Information System (INIS)

    Aubert, I.; Olive, J.M.

    2007-01-01

    The aim of this work is to quantify the absorbed hydrogen effects on the plastic deformation (at the grain scale) of stainless steel-316L polycrystals. Tensile tests in air have been carried out on specimens previously cathodically loaded in hydrogen (135 wt.ppm) and unloaded polycrystals. After the tensile tests, a number statistically representative of gliding bands emergent in surface has been observed. In parallel to this experimental study, the plastic gliding level in each grain has been obtained by a finite element method from the polycrystalline microstructure modeled with the EBSD cartography. The Zebulon code developed by the Ecole des Mines de Paris allows to account for the plastic behaviour of the studied polycrystals using the crystalline plasticity model. The coupled analysis of the numerical and experimental results allows to know the gliding plan having produced the gliding steps observed in each grain by AFM. This allows then to quantify the number of emergent dislocations to create the average gliding band. It is then possible to compare the modifications of the positioning of the plastic deformation of the stainless steel-316L induced by hydrogen absorption. (O.M.)

  12. Actuation of Pneumatic Artificial Muscle via Hydrogen Absorption/Desorption of Metal Hydride-LaNi5

    Directory of Open Access Journals (Sweden)

    Thanana Nuchkrua

    2015-01-01

    Full Text Available This paper presents experimental studies on mechanical actuations of a pneumatic artificial muscle (PAM, which is driven by hydrogen gas based metal hydride (MH. The dynamic performances of hydrogen absorption/desorption, taking place within a MH reactor, are controlled via implementing cooling/heating effects of a thermoelectric module (TEM. Hydrogen pressure is applied as a driving force to commanding work outputs of the PAM as desired mechanical actuations. Due to strong inherent nonlinearity, a conventional proportional integral derivative (PID control law is not capable of regulating thermodynamic variables of the HM reaction according to desired performances of the PAM. In this study, the fuzzy adaptive PID control is proposed in manipulating the MH reaction via the TEM. This viability of the proposed methodology is confirmed by the fact that the gains of PID control law are adapted by fuzzy rule-based tuning scheme at various operating conditions of the MH reactor. The experimental results show that the proposed control technique is much more effective than a PID control in both transient and steady state performances of the MH reactor for servo mechanical actuation of the PAM.

  13. Hydrogen absorption in thin ZnO films prepared by pulsed laser deposition

    Czech Academy of Sciences Publication Activity Database

    Melikhova, O.; Čížek, J.; Lukáč, F.; Vlček, M.; Novotný, Michal; Bulíř, Jiří; Lančok, Ján; Anwand, W.; Brauer, G.; Connolly, J.; McCarthy, E.; Krishnamurthy, S.; Mosnier, J.-P.

    2013-01-01

    Roč. 580, suppl. 1 (2013), S40-S43 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GAP108/11/0958 Institutional support: RVO:68378271 Keywords : defects * hydrogen * positron annihilation * thin films * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.726, year: 2013

  14. effect of the hydrogen absorption on the plastic deformation localization of a 316L stainless steel

    International Nuclear Information System (INIS)

    Aubert, I.

    2007-01-01

    This study is realized in the context of the aging evaluation resulting from the coupling between a mechanical constraint and corrosive conditions, as the stress corrosion or the fatigue corrosion. In this study the authors evaluate quantitatively the hydrogen effect on the plasticity at the grain scale. (A.L.B.)

  15. Strong Hydrogen Absorption at Cosmic Dawn: The Signature of a Baryonic Universe

    Science.gov (United States)

    McGaugh, Stacy S.

    2018-03-01

    The recently reported detection of redshifted 21cm absorption at $z \\approx 17$ is a significant advance in the exploration of the cosmic dark ages. The observed signal ($T_{\\mathrm{21}} \\approx -0.5$ K with the limit $T_{\\mathrm{21}} universe.

  16. On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

    Science.gov (United States)

    Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Fantz, U.; Franzen, P.; Minea, T.

    2014-10-01

    The development of a large area (Asource,ITER = 0.9 × 2 m2) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (Asource,BATMAN ≈ 0.32 × 0.59 m2) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child-Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion-ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions

  17. Application of polymeric foams for separation, storage and absorption of hydrogen

    Czech Academy of Sciences Publication Activity Database

    Pientka, Zbyněk; Nemestóthy, N.; Bélafi-Bakó, K.

    2009-01-01

    Roč. 241, 1-3 (2009), s. 106-110 ISSN 0011-9164. [Membrane Science and Technology Conference of Visegrad Countries PERMEA 2007 /3./. Siofok, 02.09.2007-06.09.2007] R&D Projects: GA ČR GA203/06/1207 Institutional research plan: CEZ:AV0Z40500505 Keywords : gas separation * hydrogen * polymeric foam Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.034, year: 2009

  18. Proton emission from resonant laser absorption and self-focusing effects from hydrogenated structures

    Czech Academy of Sciences Publication Activity Database

    Cutroneo, M.; Torrisi, L.; Margarone, Daniele; Picciotto, A.

    2013-01-01

    Roč. 272, May (2013), s. 50-54 ISSN 0169-4332 R&D Projects: GA MŠk EE.2.3.20.0087 Grant - others:OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087 Institutional support: RVO:68378271 Keywords : resonant absorption * self-focusing * Thomson parabola * spectrometer Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.538, year: 2013

  19. Phytosterol stearate esters elicit similar responses on plasma lipids and cholesterol absorption but different responses on fecal neutral sterol excretion and hepatic free cholesterol in male Syrian hamsters.

    Science.gov (United States)

    Ash, Mark M; Hang, Jiliang; Dussault, Patrick H; Carr, Timothy P

    2011-07-01

    The dietary impact of specific phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non-high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver-but not plasma-and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Numerical study of hydrogen absorption in a LM-Ni5 hybride reactor

    International Nuclear Information System (INIS)

    Altinisik, K.; Tekin, M.; Mat, M. D.; Altinisik, A.; Veziroglu, T. N.

    2007-01-01

    Metal hydride formation in an Lm-Ni5 storage tank is numerically studied with a continuum mathematical model. The model considers complex heat, and mass transfer and chemical reaction in the reaction bed. It is found that hydride formation enhances at regions with lower equilibrium pressure. Absorbed hydrogen mass increases exponentially at earlier times of hydriding process and slow down after temperature of reaction bed increases due to the heat of reaction. Numerical results agree satisfactorily with the experimental data in the literature

  1. Thermodynamic modeling of hydrogen sulfide absorption by aqueous N-methyldiethanolamine using the Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2015-01-01

    Aqueous MDEA is the most commonly used solvent for H2S removal from natural gas. A reliable thermodynamic model is required for the proper design of natural gas sweetening processes. In this study, a rigorous thermodynamic model is developed to represent properties of the H2S-MDEA-H2O ternary...... system. The Extended UNIQUAC model is used to represent the system behavior. The model is created based on models for the constituent binary subsystems. The developed model provides accurate representation of VLE and heat of absorption for the studied system and subsystem in the temperature range of 0...

  2. Investigation of structural and hydrogen absorption properties in the LaNi5-xPtx-H2 system

    International Nuclear Information System (INIS)

    Joubert, J.-M.; Charton, J.; Percheron-Guegan, A.

    2003-01-01

    The substitution of nickel by platinum in the binary LaNi 5 compound (CaCu 5 structure type, a=5.019(1) A, c=3.981(1) A, space group P6/mmm) and its effect on the hydrogenation properties was studied. The phase LaNi 5-x Pt x has a homogeneity domain ranging from x=0 to 5. For x 3. Contrary to what is observed in other systems, the hydrogen absorption plateau pressure was found to increase as a function of the cell volume. Powder neutron diffraction experiments were conducted for two deuterated compounds with x=0.25 and 0.75. Deuterium partial ordering occurs in the case of x=0.25 leading to a symmetry decrease to the space group P6mm (LaNi 4.75 Pt 0.25 D 5.23 , a=4.225(1) A, c=5.357(1) A, Z=1, R Bragg =3.3%). For x=0.75, an orthorhombic superstructure based on the CaCu 5 -type lattice was found (LaNi 4.25 Pt 0.75 D 2.61 , a orth =√3a hex =9.089(1) A, b orth =b hex =5.272(1) A, c orth =2c hex =8.145(1) A, Z=4, SG Ibam, R Bragg =6.1%)

  3. On design of absorption, regeneration and recovery system of low concentration hydrogen and tritium in He with titanium sponge

    International Nuclear Information System (INIS)

    Fukuhara, Masashi

    1978-01-01

    Design of a titanium sponge system to remove hydrogen from the helium coolant of high temperature gas-cooled reactors or fusion reactors is discussed in this paper. The data for the present purpose have been accumulated. The equilibrium relation of Ti-H 2 system was given by McQuillan. The present author of this paper obtained an absorption equilibrium diagram, and measurements were made for lower partial pressure than that of McQuillan's data. A breakthrough curve and an adsorption-desorption breakthrough curve of H 2 -Ti sponge system, and the regeneration characteristics of the Ti sponge were measured. As the results of experiments, it is said that tritium and hydrogen can be removed with a Ti sponge system. Examples of the design of a practical system are presented. A disposable system was designed for OGL-1 under the principle that the used Ti sponge is a solid radioactive waste. A regenerative system was designed as a system, in which solid radioactive wastes are not produced. An example of a recovery system is also presented. Discussion on the reason why the Ti-sponge has not been used is presented. (Kato, T.)

  4. Facile synthesis of self-assembled SnO nano-square sheets and hydrogen absorption characteristics

    International Nuclear Information System (INIS)

    Iqbal, M. Zubair; Wang, Fengping; Feng, Ting; Zhao, Hailei; Rafique, M. Yasir; Rafi ud Din; Farooq, M. Hassan; Javed, Qurat ul ain; Khan, Dil Faraz

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Self-assembled stannous oxide (SnO) 2D nano-square sheets have been synthesized. ► The average size of the nano-square sheets is about 200–400 nm. ► Direct optical band gap of 3.16 eV was acquired by using Davis–Mott model. ► The hydrogen absorption capacity of as-synthesized material was 1.194 wt.% comparatively good. -- Abstract: Stannous oxide is an important functional material which contributes to a wide range of applications in energy storage and optoelectronic devices. In the present study, the single crystalline self-assembled stannous oxide (SnO) 2D nano-square sheets have been synthesized with template-free hydrothermal growth method. The morphology, composition and structure were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Raman spectroscopy, respectively. FESEM results have illustrated that the size of self-assembled 3D hierarchical polygon-shape structure of SnO is in the range of 8–12 μm and the average size of the nano-square sheets is about 100 nm. X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns have revealed that the prepared SnO nano-square sheets exist in single-crystalline nature. Two Raman modes A 1g = 211 cm −1 and B 1g = 113 cm −1 were observed by Raman spectroscopy, which is consistent with nano tetragonal phase SnO. Furthermore, the chemical valence of Sn and relative atomic composition of as-prepared SnO have been confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet–visible–near infrared spectrophotometry was used to study the transmittance behavior of SnO nano-structures and direct optical band gap of 3.16 eV was acquired by using Davis–Mott model. The first ever study on hydrogen absorption

  5. Self-Templating Construction of Hollow Amorphous CoMoS4Nanotube Array towards Efficient Hydrogen Evolution Electrocatalysis at Neutral pH.

    Science.gov (United States)

    Wang, Weiyi; Ren, Xiang; Hao, Shuai; Liu, Zhiang; Xie, Fengyu; Yao, Yadong; Asiri, Abdullah M; Chen, Liang; Sun, Xuping

    2017-09-18

    Environmentally friendly electrochemical hydrogen production needs the development of earth-abundant catalyst materials for the hydrogen evolution reaction with high activity and durability at neutral pH. In this work, the self-templating construction of a hollow amorphous CoMoS 4 nanotube array on carbon cloth (CoMoS 4 NTA/CC) is reported, using hydrothermal treatment of a Co(OH)F nanowire array on CC in (NH 4 ) 2 MoS 4 solution. When used as a 3D electrode for hydrogen evolution electrocatalysis, the resulting CoMoS 4 NTA/CC demonstrates superior catalytic activity and strong long-term electrochemical durability in 1.0 M phosphate buffer solution (pH=7). It shows small onset overpotential of 21 mV and requires low overpotentials of 104 and 179 mV to drive geometrical current densities of 10 and 50 mA cm -2 , respectively. Density functional theory calculations suggest that CoMoS 4 has a more favorable hydrogen adsorption free energy than Co(OH)F. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effect of hydrogen bonding on the infrared absorption intensity of OH stretch vibrations

    Science.gov (United States)

    Athokpam, Bijyalaxmi; Ramesh, Sai G.; McKenzie, Ross H.

    2017-05-01

    We consider how the infrared intensity of a hydrogen-bonded OH stretch varies from weak to strong H-bonds using a theoretical model. We obtain trends for the fundamental and overtone transition intensities as a function of the donor-acceptor distance, a common measure of H-bond strength. Building upon our earlier work using a two-diabatic state model, we introduce a Mecke function-based dipole moment for the H-bond and calculate transition moments using one-dimensional vibrational eigenstates along the H-atom transfer coordinate. The fundamental intensity is found to be over 20-fold enhanced for strong H-bonds, where non-Condon effects are significant. We analyse isotope effects, including the secondary geometric isotope effect. The first overtone intensity varies non-monotonically with H-bond strength; suppression occurs for weak bonds but strong enhancements are possible for strong H-bonds. We also study how these trends are affected by Mecke parameter variations. For a few specific dimers, we compare our results with earlier works.

  7. Measurements of neutral hydrogen profiles on the EXTRAP-T2 reversed-field pinch from time-resolved ? line emission

    Science.gov (United States)

    Sallander, J.; Hedqvist, A.; Rachlew-Källne, E.

    1998-09-01

    The investigations of the radial distributions of 0953-4075/31/17/015/img2 emission from the EXTRAP-T2 reversed-field pinch (RFP) plasma show that the emission profile varies a lot, even during one plasma discharge. At central electron temperatures of about 150 eV it was expected that the 0953-4075/31/17/015/img2 emission should emerge from the plasma centre. In comparison, 0953-4075/31/17/015/img4 is always observed to radiate from the centre. Our measurements of 0953-4075/31/17/015/img2 emission have, however, shown that this is not always the case, the emission often comes from the plasma edge. The analysis of the measurements has led us to conclude that the edge emission comes from charge-exchange recombination with neutral hydrogen near the carbon first wall. These observations provide a way to estimate the change in neutral hydrogen density during local plasma-wall interaction.

  8. Adsorption of charged and neutral polymer chains on silica surfaces: The role of electrostatics, volume exclusion, and hydrogen bonding

    NARCIS (Netherlands)

    Spruijt, Evan; Biesheuvel, P.M.; de Vos, Wiebe Matthijs

    2015-01-01

    We develop an off-lattice (continuum) model to describe the adsorption of neutral polymer chains and polyelectrolytes to surfaces. Our continuum description allows taking excluded volume interactions between polymer chains and ions directly into account. To implement those interactions, we use a

  9. ALMACAL - III. A combined ALMA and MUSE survey for neutral, molecular, and ionized gas in an H I-absorption-selected system

    Science.gov (United States)

    Klitsch, A.; Péroux, C.; Zwaan, M. A.; Smail, I.; Oteo, I.; Biggs, A. D.; Popping, G.; Swinbank, A. M.

    2018-03-01

    Studying the flow of baryons into and out of galaxies is an important part of understanding the evolution of galaxies over time. We present a detailed case study of the environment around an intervening Ly α absorption line system at zabs = 0.633, seen towards the quasar J0423-0130 (zQSO = 0.915). We detect with ALMA the 12CO(2-1), 12CO(3-2), and 1.2 mm continuum emission from a galaxy at the redshift of the Ly α absorber at a projected distance of 135 kpc. From the ALMA detections, we infer interstellar medium conditions similar to those in low-redshift luminous infrared galaxies. Director's Discretionary Time (DDT) Multi-Unit Spectroscopic Explorer (MUSE) integral field unit observations reveal the optical counterpart of the 12CO emission line source and three additional emission line galaxies at the absorber redshift, which together form a galaxy group. The 12CO emission line detections originate from the most massive galaxy in this group. While we cannot exclude that we miss a fainter host, we reach a dust-uncorrected star formation rate (SFR) limit of >0.3 M⊙yr-1 within 100 kpc from the sightline to the background quasar. We measure the dust-corrected SFR (ranging from 3 to 50 M⊙ yr-1), the morpho-kinematics and the metallicities of the four group galaxies to understand the relation between the group and the neutral gas probed in absorption. We find that the Ly α absorber traces either an outflow from the most massive galaxy or intragroup gas. This case study illustrates the power of combining ALMA and MUSE to obtain a census of the cool baryons in a bounded structure at intermediate redshift.

  10. Kinetics and thermodynamics of hydrogen absorption and release in {beta}-titanium alloys; Kinetik und Thermodynamik der Wasserstoffaufnahme und -abgabe von {beta}-Titanlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Decker, M.; Christ, H.J. [Siegen Univ. (Gesamthochschule) (Germany). Inst. fuer Werkstofftechnik

    1998-12-31

    The work reported was intended to yield results allowing to describe as completely as possible the processes of interaction of {beta}-titanium and hydrogen. Three alloys have been selected for the experiments which suitably differ in stability of the {beta} phase. The characterisation of the hydrogen/metal interactions is primarily based on gravimetric measurements. A method was found to determine the diffusion coefficient of hydrogen, which is a significant variable for quantitative characterisation of the hydrogen absorption rate. (orig./CB) [Deutsch] In der Arbeit wird eine moeglichst vollstaendige Beschreibung der Wechselwirkung von {beta}-Titanlegierungen mit Wasserstoff angestrebt. Hierfuer wird mit drei Legierungen gearbeitet, die sich hinsichtlich der Stabilitaet der {beta}-Phase in sinnvoll abgestufter Weise unterscheiden. Fuer die Charakterisierung der Wasserstoff/Metall-Wechselwirkung wurden insbesondere gravimetrische Messungen eingesetzt. Weiterhin wurde die fuer eine quantitative Beschreibung der Wasserstoffaufnahmegeschwindigkeit wichtige Groesse des Diffusionskoeffizienten von Wasserstoff mit einem Verfahren bestimmt. (orig./MM)

  11. An Unusual Strong Visible-Light Absorption Band in Red Anatase TiO2 Photocatalyst Induced by Atomic Hydrogen-Occupied Oxygen Vacancies.

    Science.gov (United States)

    Yang, Yongqiang; Yin, Li-Chang; Gong, Yue; Niu, Ping; Wang, Jian-Qiang; Gu, Lin; Chen, Xingqiu; Liu, Gang; Wang, Lianzhou; Cheng, Hui-Ming

    2018-02-01

    Increasing visible light absorption of classic wide-bandgap photocatalysts like TiO 2 has long been pursued in order to promote solar energy conversion. Modulating the composition and/or stoichiometry of these photocatalysts is essential to narrow their bandgap for a strong visible-light absorption band. However, the bands obtained so far normally suffer from a low absorbance and/or narrow range. Herein, in contrast to the common tail-like absorption band in hydrogen-free oxygen-deficient TiO 2 , an unusual strong absorption band spanning the full spectrum of visible light is achieved in anatase TiO 2 by intentionally introducing atomic hydrogen-mediated oxygen vacancies. Combining experimental characterizations with theoretical calculations reveals the excitation of a new subvalence band associated with atomic hydrogen filled oxygen vacancies as the origin of such band, which subsequently leads to active photo-electrochemical water oxidation under visible light. These findings could provide a powerful way of tailoring wide-bandgap semiconductors to fully capture solar light. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Electrolyte Engineering Toward Efficient Hydrogen Production Electrocatalysis with Oxygen-crossover Regulation under Densely Buffered Near-neutral pH Conditions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-12-30

    This study tackles the core issues associated with near-neutral pH water splitting, particularly regarding electrolyte engineering in the electrocatalysis and product cross-over. We demonstrate that solute engineering has a major impact on water splitting electrocatalysis because the diffusion component, often not well integrated into performance descriptions, largely determines the overall performance. The hydrogen evolution reaction (HER) was investigated on Pt, Ni and NiMo catalysts in various concentrations of cations (Li+, K+, Na+) and anions (H2PO4−, HPO42−, PO43− and HCO3−) to describe its performance by quantifying kinetics, diffusion and solution resistance. In fact, the choice of electrolyte in terms of its identity and activity drastically altered the HER rate and oxygen mass-transport flux at near-neutral pH. Electrolyte properties (activity coefficient, kinematic viscosity and diffusion coefficient) accurately described the diffusion contribution, which can be easily isolated when a highly active Pt catalyst was used for the HER. By analyzing these properties, we maximized the HER rate on the Pt by tuning the solute concentration (typically 1.5 – 2.0 M). Moreover, the kinematic viscosity and oxygen solubility in such densely buffered conditions governed the oxygen mass-transport flux in the electrolyte, which in turn tuned the cross-over flux. At near-neutral pH, as high as 90 % selectivity toward the HER was achieved even under an oxygen saturated condition, where only a 40 mV overpotential was needed to achieve 10 mA cm−2 for the HER. This information can be regarded as an important milestone for achieving a highly efficient water splitting system at near-neutral pH.

  13. Atomic-level Pd-Pt alloying and largely enhanced hydrogen-storage capacity in bimetallic nanoparticles reconstructed from core/shell structure by a process of hydrogen absorption/desorption.

    Science.gov (United States)

    Kobayashi, Hirokazu; Yamauchi, Miho; Kitagawa, Hiroshi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki

    2010-04-28

    We have achieved the creation of a solid-solution alloy where Pd and Pt are homogeneously mixed at the atomic level, by a process of hydrogen absorption/desorption as a trigger for core (Pd)/shell (Pt) nanoparticles. The structural change from core/shell to solid solution has been confirmed by in situ powder X-ray diffraction, energy dispersive spectra, solid-state (2)H NMR measurement, and hydrogen pressure-composition isotherms. The successfully obtained Pd-Pt solid-solution nanoparticles with a Pt content of 8-21 atom % had a higher hydrogen-storage capacity than Pd nanoparticles. Moreover, the hydrogen-storage capacity of Pd-Pt solid-solution nanoparticles can be tuned by changing the composition of Pd and Pt.

  14. Planetary gamma-ray spectroscopy: the effects of hydrogen absorption cross-section of the gamma-ray spectrum

    International Nuclear Information System (INIS)

    Lapides, J.R.

    1981-01-01

    The gamma-ray spectroscopy of planet surfaces is one of several possible methods that are useful in determining the elemental composition of planet surfaces from orbiting spacecraft. This has been demonstrated on the Apollos 15 and 16 missions as well as the Soviet Mars-5 mission. Planetary gamma-ray emission is primarily the result of natural radioactive decay and cosmic-ray and solar-flare-induced nuclear reactions. Secondary neutron reactions play a large role in the more intense gamma-ray emission. The technique provides information on the elemental composition of the top few tens of centimeters of the planet surface. Varying concentrations of hydrogen and compositional variations that alter the macroscopic thermal-neutron absorption cross section have a significant effect on the neutron flux in the planet surface and therefore also on the gamma-ray emission from the surface. These effects have been systematically studied for a wide range of possible planetary compositions that include Mercury, the moon, Mars, the comets, and the asteroids. The problem of the Martian atmosphere was also investigated. The results of these calculations, in which both surface neutron fluxes and gamma-ray emission fluxes were determined, were used to develop general procedures for obtaining planet compositions from the gamma-ray spectrum. Several changes have been suggested for reanalyzing the Apollos 15 and 16 gamma-ray results. In addition, procedures have been suggested that can be applied to neutron-gamma techniques in mineral and oil exploration

  15. Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1943-02-19

    A transcript is presented of a speech on the history of the development of hydrogenation of coal and tar. Apparently the talk had been accompanied by the showing of photographic slides, but none of the pictures were included with the report. In giving the history, Dr. Pier mentioned the dependence of much of the development of hydrogenation upon previous development in the related areas of ammonia and methanol syntheses, but he also pointed out several ways in which equipment appropriate for hydrogenation differed considerably from that used for ammonia and methanol. Dr. Pier discussed the difficulties encountered with residue processing, design of the reaction ovens, manufacture of ovens and preheaters, heating of reaction mixtures, development of steels, and development of compressor pumps. He described in some detail his own involvement in the development of the process. In addition, he discussed the development of methods of testing gasolines and other fuels. Also he listed some important byproducts of hydrogenation, such as phenols and polycyclic aromatics, and he discussed the formation of iso-octane fuel from the butanes arising from hydrogenation. In connection with several kinds of equipment used in hydrogenation (whose pictures were being shown), Dr. Pier gave some of the design and operating data.

  16. Porous grape-like spherical silica with hydrogen storage capability, synthesized using neutral dual surfactants as templates

    Energy Technology Data Exchange (ETDEWEB)

    Du, Li; Liao, Shijun; Liu, Quanbing; Yang, Xu; Song, Huiyu; Fu, Zhiyong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Ji, Shan [South Africa Institute for Advanced Materials Chemistry, University of the Western Cape (South Africa)

    2009-05-15

    By using two non-ionic surfactants, 1,12-diaminododecane and a triblock copolymer surfactant F127, as templates, grape-like solid spheres of super-microporous silica (SMS) with ordered, worm-like pore structures have been successfully synthesized, then characterized by SEM/TEM, XRD, TG/DTA, etc. In a sample synthesized at 70 C, well-formed grape-like spheres with worm-like pores were observed by SEM and TEM. The average pore size is ca. 1.87 nm and the specific surface area of the spheres is 865 m{sup 2}/g. The hydrogen storage capacity of the sample Pd/SMS-70-C, prepared by supporting 5 wt% palladium on SMS (synthesized at 70 C), is up to 2.56 wt% at 1.2 MPa hydrogen pressure. (author)

  17. Comparison of high energy gamma rays from absolute value of b greater than 30 deg with the galactic neutral hydrogen distribution

    Science.gov (United States)

    Ozel, M. E.; Ogelman, H.; Tumer, T.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, F. J.

    1978-01-01

    High-energy gamma-ray (energy above 35 MeV) data from the SAS 2 satellite have been used to compare the intensity distribution of gamma rays with that of neutral hydrogen (H I) density along the line of sight, at high galactic latitudes (absolute values greater than 30 deg). A model has been constructed for the case where the observed gamma-ray intensity has been assumed to be the sum of a galactic component proportional to the H I distribution plus an isotropic extragalactic emission. A chi-squared test of the model parameters indicates that about 30% of the total high-latitude emission may originate within the Galaxy.

  18. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    The idea of a "Hydrogen Economy" is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO₂ in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H₂ from the electrolyzer. Methanol made with CO₂ from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan). Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs) by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  19. New Insight into the Hydrogen Evolution Reaction under Buffered Near-Neutral pH Conditions: Enthalpy and Entropy of Activation

    KAUST Repository

    Shinagawa, Tatsuya

    2016-10-06

    Electrochemical conversion of thermodynamically stable chemicals of water and carbon dioxide is regarded as a core technology for achieving sustainability in our society. In both cases, the electrochemical hydrogen evolution reaction (HER) is a key reaction, particularly at near-neutral pH. This study addresses the kinetic aspects of the HER in buffered near-neutral pH conditions using a variety of electrode materials (W, Ni, Pt, Au, and Cu) over a wide temperature range (299–346 K). When the overall performance was summarized with respect to the binding energy of the reaction intermediate species, a classic volcano-shaped relationship was obtained. Interestingly, the temperature sensitivity analysis disclosed that smaller activation energies did not always lead to higher performance in 1.5 mol L–1 K-phosphate solution (pH 5.8). Detailed analysis of the temperature- and potential-dependent parameters revealed that smaller activation energies coincided with smaller values of the pre-exponential factor in the Arrhenius’ equation (associated with the entropy of activation). Due to the trade-off relationship of enthalpy–entropy compensation in the current system, the conventional approach of mixing elements of lower and higher binding energies to the intermediate species failed: even though Ni–Cu showed lower apparent activation energy, its activity toward the HER was between that of Ni and Cu due to the lowered entropy of activation. This study demonstrates the unrevealed fundamental aspects of the HER in buffered near-neutral condition, which contributes to the rational development of efficient energy and material conversion systems.

  20. Modeling of the negative ions extraction from a hydrogen plasma source. Application to ITER Neutral Beam Injector

    International Nuclear Information System (INIS)

    Mochalskyy, S.

    2011-12-01

    The development of a high performance negative ion (NI) source constitutes a crucial step in the construction of a Neutral Beam Injector of the future fusion reactor ITER. NI source should deliver 40 A of H - or of D - . To address this problem in a realistic way, a 3D particles-in-cell electrostatic collisional code was developed. Binary collisions between the particles are introduced using Monte-Carlo collision scheme. This code called ONIX was used to investigate the plasma properties and the transport of the charged particles close to a typical extraction aperture. Results obtained from this code are presented in this thesis. They include negative ions and electrons 3D trajectories. The ion and electron current density profiles are shown for different local magnetic field configurations. Results of production, destruction, and transport of H - in the extraction region are also presented. The production of H - is investigated via 3 atomic processes: 1) electron dissociative attachment to the vibrationally excited molecules H 2 (v) in the volume, 2) interaction of the positive ions H + and H 2 + with the aperture wall and 3) collisions of the neutral gas H, H 2 with aperture wall. The influence of each process on the total extracted NI current is discussed. The extraction efficiency of H - from the volume is compared to the one of H - coming from the wall. Moreover, a parametric study of the H - surface production is presented. Results show the role of sheath behavior in the vicinity of the aperture developing a double layer structure responsible of the NI extraction limitations. The 2 following issues are also analysed. First the influence of the external extracted potential value on the formation of negative sheath and secondly the strength of the magnetic filter on the total extracted NI and co-extracted electron current. The suppression of the electron beam by the negative ion produced at the plasma grid wall is also discussed. Results are in good agreement

  1. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  2. In situ NRA study of hydrogen isotope exchange in self-ion damaged tungsten exposed to neutral atoms

    International Nuclear Information System (INIS)

    Markelj, S.; Založnik, A.; Schwarz-Selinger, T.; Ogorodnikova, O.V.; Vavpetič, P.; Pelicon, P.; Čadež, I.

    2016-01-01

    Isotope exchange was studied in-situ by Nuclear Reaction Analysis in the bulk of self-ion damaged tungsten at 600 K. Both variations of isotope exchange of H by D and of D by H were measured. The deuterium isothermal desorption was also studied and evaluated in order to be able to resolve the self-desorption from the isotope exchange at 600 K. The isotope exchange was also studied on the surface by Elastic Recoil Detection Analysis at 480 K and 380 K. The exchange mechanism was effective both on the surface and in the bulk of damaged tungsten. A simple model was introduced to describe the exchange efficiency on the surface and in the bulk obtaining the exchange cross sections on the surface and in bulk. In both cases an isotope effect was observed, where the exchange of H atoms by D atoms was more efficient than for the reverse sequence. - Highlights: • First study of isotope exchange on surface and in bulk of self-ion damaged tungsten by exposure to neutral atoms. • In situ study by ion beam techniques NRA and ERDA. • Modelling of the isotope exchange mechanism.

  3. Ethylene hydrogenation catalysis on Pt(111) single-crystal surfaces studied by using mass spectrometry and in situ infrared absorption spectroscopy

    Science.gov (United States)

    Tillekaratne, Aashani; Simonovis, Juan Pablo; Zaera, Francisco

    2016-10-01

    The catalytic hydrogenation of ethylene promoted by a Pt(111) single crystal was studied by using a ultrahigh-vacuum surface-science instrument equipped with a so-called high-pressure cell. Kinetic data were acquired continuously during the catalytic conversion of atmospheric-pressure mixtures of ethylene and hydrogen by using mass spectrometry while simultaneously characterizing the surface species in operando mode by reflection-absorption infrared spectroscopy (RAIRS). Many observations reported in previous studies of this system were corroborated, including the presence of adsorbed alkylidyne intermediates during the reaction and the zero-order dependence of the rate of hydrogenation on the pressure of ethylene. In addition, the high quality of the kinetic data, which could be recorded continuously versus time and processed to calculate time-dependent turnover frequencies (TOFs), afforded a more detailed analysis of the mechanism. Specifically, deuterium labeling could be used to estimate the extent of isotope scrambling reached with mixed-isotope-substituted reactants (C2H4 + D2 and C2D4 + H2). Perhaps the most important new observation from this work is that, although extensive H-D exchange takes place on ethylene before being fully converted to ethane, the average stoichiometry of the final product retains the expected stoichiometry of the gas mixture, that is, four regular hydrogen atoms and two deuteriums per ethane molecule in the case of the experiments with C2H4 + D2. This means that no hydrogen atoms are removed from the surface via their inter-recombination to produce X2 (X = H or D). It is concluded that, under catalytic conditions, hydrogen surface recombination is much slower than ethylene hydrogenation and H-D exchange.

  4. He II Raman Scattered Line by Neutral Hydrogen in the Bipolar Platenary Nebula M2-9

    Directory of Open Access Journals (Sweden)

    Hee-Won Lee

    2001-06-01

    Full Text Available In the spectrum of the young bipolar planetary nebula M2-9 obtained from the 1.5 m telescope at the Cerro Tololo Inter-American Observatory, we detected the He~II feature at 6545 Å that are proposed to be formed via Raman scattering by atomic hydrogen. However, in the same spectrum, the He~II emission lines at 6527 Å and 6560 Å are absent, which implies that the He~II emission region is hidden from our line of sight and that the H~I scattering region is pretty much extended not to be obscured entirely. We performed photoionization computations to estimate the physical size of the He~II emission line region to be 1016 cm, from which the location and dimension of the obscuring circumstellar region are inferred and the temperature of the central star must exceed 105 K. The angular size of the circumstellar region responsible for the obscuration of the He~II emission region is ~ 1'' with the assumption of the distance 01 kpc to M2-9, which is consistent with the recent image of M2-9 obtained with the Hubble Space Telescope.

  5. In-Situ X-ray Absorption Spectroscopy as an Unique Tool for Obtaining Information on Hydrogen Binding Site and Electronic Structure of Supported Pt Catalysts: Towards an Understanding of the Compensation Relation in Alkane Hydrogenolysis

    NARCIS (Netherlands)

    Koningsberger, D.C.; Oudenhuijzen, M.K.; Bokhoven, J.A. van; Ramaker, D.E.

    2003-01-01

    L2 and L3 X-ray absorption near edge spectra (XANES) on supported Pt particles, with and without chemisorbed hydrogen, are shown to reflect the type of hydrogen-binding site on the Pt surface. FEFF8 ab initio multiple scattering calculations are used to determine XANES spectral fingerprints for the

  6. First calibration measurements of an FTIR absorption spectroscopy system for liquid hydrogen isotopologues for the isotope separation system of fusion power plants

    International Nuclear Information System (INIS)

    Groessle, R.; Beck, A.; Bornschein, B.; Fischer, S.; Kraus, A.; Mirz, S.; Rupp, S.

    2015-01-01

    Fusion facilities like ITER and DEMO will circulate huge amounts of deuterium and tritium in their fuel cycle with an estimated throughput of kg per hour. One important capability of these fuel cycles is to separate the hydrogen isotopologues (H 2 , D 2 , T 2 , HD, HT, DT). For this purpose the Isotope Separation System (ISS), using cryogenic distillation, as part of the Tritium Enrichment Test Assembly (TRENTA) is under development at Tritium Laboratory Karlsruhe. Fourier transform infrared absorption spectroscopy (FTIR) has been selected to prove its capability for online monitoring of the tritium concentration in the liquid phase at the bottom of the distillation column of the ISS. The actual research-development work is focusing on the calibration of such a system. Two major issues are the identification of appropriate absorption lines and their dependence on the isotopic concentrations and composition. For this purpose the Tritium Absorption IR spectroscopy experiment has been set up as an extension of TRENTA. For calibration a Raman spectroscopy system is used. First measurements, with equilibrated mixtures of H 2 , D 2 and HD demonstrate that FTIR can be used for quantitative analysis of liquid hydro-gen isotopologues and reveal a nonlinear dependence of the integrated absorbance from the D 2 concentration in the second vibrational branch of D 2 FTIR spectra. (authors)

  7. Study of Synchrotron Radiation Near-Edge X-Ray Absorption Fine-Structure of Amorphous Hydrogenated Carbon Films at Various Thicknesses

    Directory of Open Access Journals (Sweden)

    Sarayut Tunmee

    2015-01-01

    Full Text Available The compositions and bonding states of the amorphous hydrogenated carbon films at various thicknesses were evaluated via near-edge X-ray absorption fine-structure (NEXAFS and elastic recoil detection analysis combined with Rutherford backscattering spectrometry. The absolute carbon sp2 contents were determined to decrease to 65% from 73%, while the hydrogen contents increase from 26 to 33 at.% as the film thickness increases. In addition, as the film thickness increases, the π⁎ (C=C, σ⁎ (C–H, σ⁎ (C=C, and σ⁎ (C≡C bonding states were found to increase, whereas the π⁎ (C≡C and σ⁎ (C–C bonding states were observed to decrease in the NEXAFS spectra. Consequently, the film thickness is a key factor to evaluate the composition and bonding state of the films.

  8. Can the Discrepancy between Locally and Globally Derived Neutral Hydrogen Mass Functions be Explained by a Varying Value of M ⋆?

    Science.gov (United States)

    Minchin, Robert F.

    2017-09-01

    I investigate whether it is possible to reconcile the recent Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) observation that the neutral hydrogen mass function (HIMF) across different galactic densities has the same, non-flat, faint-end slope, with observations of isolated galaxies and many galaxy groups that show their HIMFs to have flat faint-end slopes. I find that a fairly simple model in which the position of the knee in the mass function of each individual group is allowed to vary is able to account for both of these observations. If this model reflects reality, the ALFALFA results point to an interesting “conspiracy” whereby the differing group HIMFs always sum up to form global HIMFs with the same faint-end slope in different environments. More generally, this result implies that global environmental HIMFs do not necessarily reflect the HIMFs in individual groups belonging to that environment and cannot be used to directly measure variations in group-specific HIMFs with environment.

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

    Science.gov (United States)

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

    2016-01-01

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

  10. Tensile Characteristics of Bond of Stainless Steel Overlay Weld after Absorption of Hydrogen : Study on a Stainless Steel Overlay Welding Process for Superior Resistance to Disbonding (Report 4)

    OpenAIRE

    Akiyoshi, FUJI; Etsuo, KUDO; Tomoyuki, TAKAHASHI; The Japan Steel Works, Ltd., Muroran Plant; The Japan Steel Works, Ltd., Muroran; The Japan Steel Works, Ltd., Muroran Plant

    1987-01-01

    The tensile characteristics of the bond of the disbanding-resistant overlay weld after absorption of hydrogen were studied and compared with those of the conventional overlay weld. It was found that the tensile strength of the bond of the conventional overlay weld was lower than that of the disbanding-resistant overlay weld. This is due to existence of the coarse planar grains in first layer overlay weld metal adjacent to the bond. The coarse planar grains strongly reduce the resistance to hy...

  11. The investigation of hydrogens bonds between sulphur-bearing heterocyclic and proton-donor compounds by IR absorption spectra

    International Nuclear Information System (INIS)

    Narziev, B.N.; Nurulloev, M.; Makhkambaev, D.

    1982-01-01

    In this article the results of intermolecular interaction study of sulfur-containing heterocyclic (thiophene, thiophane) and proton-donar (water, alcohol, carbonic acids, chlorophon) molecules for measuring of IR spectrum absorption of protondonar compounds in soluted shape are presented

  12. High-resolution IR absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region: role of hydrogenation and alkylation

    Science.gov (United States)

    Maltseva, Elena; Mackie, Cameron J.; Candian, Alessandra; Petrignani, Annemieke; Huang, Xinchuan; Lee, Timothy J.; Tielens, Alexander G. G. M.; Oomens, Jos; Buma, Wybren Jan

    2018-03-01

    Aim. We aim to elucidate the spectral changes in the 3 μm region that result from chemical changes in the molecular periphery of polycyclic aromatic hydrocarbons (PAHs) with extra hydrogens (H-PAHs) and methyl groups (Me-PAHs). Methods: Advanced laser spectroscopic techniques combined with mass spectrometry were applied on supersonically cooled 1,2,3,4-tetrahydronaphthalene, 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, 1,2,3,6,7,8-hexahydropyrene, 9-methylanthracene, and 9,10-dimethylanthracene, allowing us to record mass-selective and conformationally selective absorption spectra of the aromatic, aliphatic, and alkyl CH-stretches in the 3.175 - 3.636 µm region with laser-limited resolution. We compared the experimental absorption spectra with standard harmonic calculations and with second-order vibrational perturbation theory anharmonic calculations that use the SPECTRO program for treating resonances. Results: We show that anharmonicity plays an important if not dominant role, affecting not only aromatic, but also aliphatic and alkyl CH-stretch vibrations. The experimental high-resolution data lead to the conclusion that the variation in Me- and H-PAHs composition might well account for the observed variations in the 3 μm emission spectra of carbon-rich and star-forming regions. Our laboratory studies also suggest that heavily hydrogenated PAHs form a significant fraction of the carriers of IR emission in regions in which an anomalously strong 3 μm plateau is observed.

  13. Electronic Absorption Spectra of Neutral Perylene (C20H12), Terrylene (C30H16), and Quaterrylene (C40H20) and their Positive and Negative Ions: Ne Matrix-Isolation Spectroscopy and Time Dependent Density Functional Theory Calculations

    Science.gov (United States)

    Halasinski, Thomas M.; Weisman, Jennifer L.; Lee, Timothy J.; Salama, Farid; Head-Gordon, Martin; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We present a full experimental and theoretical study of an interesting series of polycyclic aromatic hydrocarbons, the oligorylenes. The absorption spectra of perylene, terrylene and quaterrylene in neutral, cationic and anionic charge states are obtained by matrix-isolation spectroscopy in Ne. The experimental spectra are dominated by a bright state that red shifts with growing molecular size. Excitation energies and state symmetry assignments are supported by calculations using time dependent density functional theory methods. These calculations also provide new insight into the observed trends in oscillator strength and excitation energy for the bright states: the oscillator strength per unit mass of carbon increases along the series.

  14. Measurement of the rate of hydrogen peroxide thermal decomposition in a shock tube using quantum cascade laser absorption near 7.7 μm

    KAUST Repository

    Sajid, Muhammad Bilal

    2013-10-24

    Hydrogen peroxide (H2O2) is formed during hydrocarbon combustion and controls the system reactivity under intermediate temperature conditions. Here, we measured the rate of hydrogen peroxide decomposition behind reflected shock waves using midinfrared absorption of H2O 2 near 7.7 μm. We performed the experiments in diluted H 2O2/Ar mixtures between 930 and 1235 K and at three different pressures (1, 2, and 10 atm). Under these conditions, the decay of hydrogen peroxide is sensitive only to the decomposition reaction rate, H 2O2 + M → 2OH + M (k1). The second-order rate coefficient at low pressures (1 and 2 atm) did not exhibit any pressure dependence, suggesting that the reaction was in the low-pressure limit. The rate data measured at 10 atm exhibited falloff behavior. The measured decomposition rates can be expressed in Arrhenius forms as follows: k1(1 and 2 atm)=10(16.29±0.12)× exp (-21993±301/T)(cm 3 mol -1s-1) k1(10 atm)=10(15.24±0.10)× exp (-19955±247/T)(cm 3 mol -1s-1) © 2013 Wiley Periodicals, Inc.

  15. High harmonic ion cyclotron heating in DIII-D: Beam ion absorption and sawtooth stabilization

    International Nuclear Information System (INIS)

    Heidbrink, W.W.; Fredrickson, E.D.; Mau, T.K.; Petty, C.C.; Pinsker, R.I.; Porkolab, M.; Rice, B.W.

    1999-01-01

    Combined neutral beam injection and fast wave heating at the fourth cyclotron harmonic produce an energetic deuterium beam ion tail in the DIII-D tokamak. When the concentration of thermal hydrogen exceeds ∼ 5%, the beam ion absorption is suppressed in favour of second harmonic hydrogen absorption. As theoretically expected, the beam absorption increases with beam ion gyro-radius; also, central absorption at the fifth harmonic is weaker than central absorption at the fourth harmonic. For central heating at the fourth harmonic, an energetic, perpendicular, beam population forms inside the q = 1 surface. The beam ion tail transiently stabilizes the sawtooth instability but destabilizes toroidicity induced Alfven eigenmodes (TAEs). Saturation of the central heating correlates with the onset of the TAEs. Continued expansion of the q = 1 radius eventually precipitates a sawtooth crash; complete magnetic reconnection is observed. (author)

  16. Enhanced Hydrogen Evolution in the Presence of Plasmonic Au-Photo-Sensitized g-C3N4 with an Extended Absorption Spectrum from 460 to 640 nm.

    Science.gov (United States)

    Xie, Lihong; Ai, Zhuyu; Zhang, Meng; Sun, Runze; Zhao, Weirong

    2016-01-01

    Extensively spectral-responsive photocatalytic hydrogen production was achieved over g-C3N4 photo-sensitized by Au nanoparticles. The photo-sensitization, which was achieved by a facile photo-assisted reduction route, resulted in an extended spectral range of absorption from 460 to 640 nm. The photo-sensitized g-C3N4 (Au/g-C3N4) photocatalysts exhibit significantly enhanced photocatalytic hydrogen evolution with a TOF value of 223 μmol g-1 h-1, which is a 130-fold improvement over g-C3N4. The hydrogen production result confirms that Au nanoparticles are effective photo-sensitizers for the visible light-responsive substrate g-C3N4. UV-vis diffuse reflection spectra (DRS), photoluminescence spectra (PL), electron spin resonance (ESR), and electrochemical measurements were used to investigate the transfer process of photogenerated electrons. The optimal Au/g-C3N4 photocatalyst displays the lowest charge transfer resistance of 18.45 Ω cm-2 and a high electron transfer efficiency, as determined by electrochemical impedance spectroscopy (EIS). The photo-sensitized g-C3N4 shows a broad range of response to visible light (400-640 nm), with significantly high incident photon-to-current efficiency (IPCE) values of 14.52%, 2.9%, and 0.74% under monochromatic light irradiation of 400, 550, and 640 nm, respectively. ESR characterization suggests that Au nanoparticles are able to absorb visible light of wavelengths higher than 460 nm and to generate hot electrons due to the SPR effect.

  17. Enhanced Hydrogen Evolution in the Presence of Plasmonic Au-Photo-Sensitized g-C3N4 with an Extended Absorption Spectrum from 460 to 640 nm.

    Directory of Open Access Journals (Sweden)

    Lihong Xie

    Full Text Available Extensively spectral-responsive photocatalytic hydrogen production was achieved over g-C3N4 photo-sensitized by Au nanoparticles. The photo-sensitization, which was achieved by a facile photo-assisted reduction route, resulted in an extended spectral range of absorption from 460 to 640 nm. The photo-sensitized g-C3N4 (Au/g-C3N4 photocatalysts exhibit significantly enhanced photocatalytic hydrogen evolution with a TOF value of 223 μmol g-1 h-1, which is a 130-fold improvement over g-C3N4. The hydrogen production result confirms that Au nanoparticles are effective photo-sensitizers for the visible light-responsive substrate g-C3N4. UV-vis diffuse reflection spectra (DRS, photoluminescence spectra (PL, electron spin resonance (ESR, and electrochemical measurements were used to investigate the transfer process of photogenerated electrons. The optimal Au/g-C3N4 photocatalyst displays the lowest charge transfer resistance of 18.45 Ω cm-2 and a high electron transfer efficiency, as determined by electrochemical impedance spectroscopy (EIS. The photo-sensitized g-C3N4 shows a broad range of response to visible light (400-640 nm, with significantly high incident photon-to-current efficiency (IPCE values of 14.52%, 2.9%, and 0.74% under monochromatic light irradiation of 400, 550, and 640 nm, respectively. ESR characterization suggests that Au nanoparticles are able to absorb visible light of wavelengths higher than 460 nm and to generate hot electrons due to the SPR effect.

  18. Enhanced Hydrogen Evolution in the Presence of Plasmonic Au-Photo-Sensitized g-C3N4 with an Extended Absorption Spectrum from 460 to 640 nm

    Science.gov (United States)

    Xie, Lihong; Ai, Zhuyu; Zhang, Meng; Sun, Runze; Zhao, Weirong

    2016-01-01

    Extensively spectral-responsive photocatalytic hydrogen production was achieved over g-C3N4 photo-sensitized by Au nanoparticles. The photo-sensitization, which was achieved by a facile photo-assisted reduction route, resulted in an extended spectral range of absorption from 460 to 640 nm. The photo-sensitized g-C3N4 (Au/g-C3N4) photocatalysts exhibit significantly enhanced photocatalytic hydrogen evolution with a TOF value of 223 μmol g-1 h-1, which is a 130-fold improvement over g-C3N4. The hydrogen production result confirms that Au nanoparticles are effective photo-sensitizers for the visible light-responsive substrate g-C3N4. UV–vis diffuse reflection spectra (DRS), photoluminescence spectra (PL), electron spin resonance (ESR), and electrochemical measurements were used to investigate the transfer process of photogenerated electrons. The optimal Au/g-C3N4 photocatalyst displays the lowest charge transfer resistance of 18.45 Ω cm-2 and a high electron transfer efficiency, as determined by electrochemical impedance spectroscopy (EIS). The photo-sensitized g-C3N4 shows a broad range of response to visible light (400–640 nm), with significantly high incident photon-to-current efficiency (IPCE) values of 14.52%, 2.9%, and 0.74% under monochromatic light irradiation of 400, 550, and 640 nm, respectively. ESR characterization suggests that Au nanoparticles are able to absorb visible light of wavelengths higher than 460 nm and to generate hot electrons due to the SPR effect. PMID:27575246

  19. The electronic and optical properties of amorphous silica with hydrogen defects by ab initio calculations

    Science.gov (United States)

    Ren, Dahua; Xiang, Baoyan; Hu, Cheng; Qian, Kai; Cheng, Xinlu

    2018-04-01

    Hydrogen can be trapped in the bulk materials in four forms: interstitial molecular H2, interstitial atom H, O‑H+(2Si=O–H)+, Si‑H‑( {{4O}}\\bar \\equiv {{Si&x2212H}})‑ to affect the electronic and optical properties of amorphous silica. Therefore, the electronic and optical properties of defect-free and hydrogen defects in amorphous silica were performed within the scheme of density functional theory. Initially, the negative charged states hydrogen defects introduced new defect level between the valence band top and conduction band bottom. However, the neutral and positive charged state hydrogen defects made both the valence band and conduction band transfer to the lower energy. Subsequently, the optical properties such as absorption spectra, conductivity and loss functions were analyzed. It is indicated that the negative hydrogen defects caused the absorption peak ranging from 0 to 2.0 eV while the positive states produced absorption peaks at lower energy and two strong absorption peaks arose at 6.9 and 9.0 eV. However, the neutral hydrogen defects just improved the intensity of absorption spectrum. This may give insights into understanding the mechanism of laser-induced damage for optical materials. Project supported by the Science and Technology of Hubei Provincial Department of Education (No. B2017098).

  20. The Effect of Toluene Solution on the Hydrogen Absorption of the Mg-Ti Alloy Prepared by Synthetic Alloying

    Directory of Open Access Journals (Sweden)

    H. Suwarno

    2009-07-01

    Full Text Available The synthesis and characterization of the Mg–Ti alloy have been carried out through a mechanical alloying technique under toluene solution. The Mg and Ti powders are milled for 10, 20, and 30 h in a high energy ball mill. The milled alloys are then hydrided at a temperature of 300 oC in order to investigate the possibility used for hydrogen storage materials. The refinement analyses of the x-ray diffraction patterns show that mechanical alloying of the Mg–Ti powders under toluene solution results in the formation of the TiH2 and Mg2Ti phases. Quantitative analyses indicate that the mass fractions of the TiH2 and Mg2Ti phases are 62.90 % and 30.60 %, while the value for Mg and Ti amount to 2.6 wt% and 1.25 wt%. On hydriding at a temperature of 300 oC, the milled powders are transformed into Mg2TiH4, TiH2 and γ-MgH2 phases with the mass fractions of 25.48 wt%, 64.0 wt%, and 10.52 wt%, respectively. Microstructure analyses show that before milling the shape of particle is mostly a ball shape, after 30 h of milling the shape of particles changes into polygonal shape, and upon hydriding the shape of particles changes from a polygonal shape into an irregular one. The final composition of the specimen after hydriding exhibits that Mg-Ti alloy can be promoted as a hydrogen storage material.

  1. Laboratory observation of the 3P1-3P0 transition of the neutral carbon atom by submillimeter-wave absorption spectroscopy

    International Nuclear Information System (INIS)

    Yamamoto, Satoshi; Saito, Shuji

    1991-01-01

    The 3P1-3P0 transitions of the neutral C-12 and C-13 atoms are observed by laboratory microwave spectroscopy. The carbon atom is produced by discharging a gaseous mixture of CO and He at the liquid nitrogen temperature. The transition frequency is precisely determined for (C-12)T to be 492160.651 + or - 0.055 MHz, where the error is three standard deviations in the frequency measurements. Two hyperfine components, F = 3/2-1/2 and F = 1/2-1/2, are observed for (C-13)I at 492164.276 + or - 0.072 MHz and 492160.147 + or - 0.168 MHz, respectively. The precise laboratory values are recommended as rest frequencies in astronomical observations. 24 refs

  2. Evaluation of vaporized hydrogen peroxide, Citrox and pH neutral Ecasol for decontamination of an enclosed area: a pilot study.

    LENUS (Irish Health Repository)

    Galvin, S

    2012-01-01

    Hydrogen peroxide, Ecasol and Citrox aerosols were each tested for their ability to kill a range of nosocomial pathogens. Hydrogen peroxide had the broadest microbicidal activity but operational issues limit its use. Ecasol was effective against all micro-organisms, except Clostridium difficile, while Citrox aerosols were not effective against Gram-negative bacilli.

  3. A survey of interstellar neutral potassium. I - Abundances and physical conditions in clouds toward 188 early-type stars

    Science.gov (United States)

    Chaffee, F. H., Jr.; White, R. E.

    1982-01-01

    Observations of interstellar absorption in the resonance doublet 7664, 7698 A of neutral potassium toward 188 early-type stars at a spectral resolution of 8 km/s are reported. The 7664 A line is successfully separated from nearly coincident telluric O2 absorption for all but a few of the 165 stars for which K I absorption is detected, making possible an abundance analysis by the doublet ratio method. The relationships between the potassium abundances and other atomic abundances, the abundance of molecular hydrogen, and interstellar reddening are investigated.

  4. Effect of the hydrogen absorption on the positioning of the plastic deformation of a stainless steel-316L; Effet de l'absorption d'hydrogene sur la localisation de la deformation plastique d'un acier inoxydable 316L

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, I.; Olive, J.M. [Bordeaux Univ., Lab. de Mecanique Physique, CNRS, 33 (France)

    2007-07-01

    The aim of this work is to quantify the absorbed hydrogen effects on the plastic deformation (at the grain scale) of stainless steel-316L polycrystals. Tensile tests in air have been carried out on specimens previously cathodically loaded in hydrogen (135 wt.ppm) and unloaded polycrystals. After the tensile tests, a number statistically representative of gliding bands emergent in surface has been observed. In parallel to this experimental study, the plastic gliding level in each grain has been obtained by a finite element method from the polycrystalline microstructure modeled with the EBSD cartography. The Zebulon code developed by the Ecole des Mines de Paris allows to account for the plastic behaviour of the studied polycrystals using the crystalline plasticity model. The coupled analysis of the numerical and experimental results allows to know the gliding plan having produced the gliding steps observed in each grain by AFM. This allows then to quantify the number of emergent dislocations to create the average gliding band. It is then possible to compare the modifications of the positioning of the plastic deformation of the stainless steel-316L induced by hydrogen absorption. (O.M.)

  5. Research on the behaviors of hydrogen absorption and desorption properties of the Ti1.08V1.21Cr0.28Fe0.40Zr0.03 alloy

    International Nuclear Information System (INIS)

    Shuai Maobing; Wu Sheng; Zhao Pengji; Yao Shujiu; Xu Zhilei

    1998-12-01

    Behaviors of hydrogen absorption-desorption and other application-oriented properties of the Ti 1.08 V 1.21 Cr 0.28 Fe 0.40 Zr 0.03 alloy were investigated. The results showed that the alloy was activated easily and had a large hydrogen absorbing content. The plateau pressure at ambient temperature was about 101325 Pa with hydrogen content about 0.8 H/M-1.6 H/M. The thermodynamic parameters of the reaction of hydrogen absorption for the hydride with H/M = 1.25 were found to be ΔH = -27.4 kJ/moleH 2 and ΔS = -200 j/(K·moleH 2 ). The hydrogen absorption and desorption reaction were fast. The hydrogen desorption ratio of the alloy hydride at 600 degree C was above 95 percent. The impurity helium had little effect on the hydrogen absorbing volume, but reduced the reaction rate obviously. While the air had obvious effects both on the absorbing volume and the reaction rate. The alloy resisted pulverization and the relative volume change of the hydride with H/M = 1.1 was only about 11 percent. And the alloy and its hydride did not self-ignite in air. Phase composition of the Ti 1.08 V 1.21 Cr 0.28 Fe 0.40 Zr 0.03 alloy and its hydride were analysed by XRD and Sem. The result showed that a multi-phase formed after hydriding

  6. Development of Hydrogenated Microcrystalline Silicon-Germanium Alloys for Improving Long-Wavelength Absorption in Si-Based Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Yen-Tang Huang

    2014-01-01

    Full Text Available Hydrogenated microcrystalline silicon-germanium (μc-Si1-xGex:H alloys were developed for application in Si-based thin-film solar cells. The effects of the germane concentration (RGeH4 and the hydrogen ratio (RH2 on the μc-Si1-xGex:H alloys and the corresponding single-junction thin-film solar cells were studied. The behaviors of Ge incorporation in a-Si1-xGex:H and μc-Si1-xGex:H were also compared. Similar to a-Si1-xGex:H, the preferential Ge incorporation was observed in μc-Si1-xGex:H. Moreover, a higher RH2 significantly promoted Ge incorporation for a-Si1-xGex:H, while the Ge content was not affected by RH2 in μc-Si1-xGex:H growth. Furthermore, to eliminate the crystallization effect, the 0.9 μm thick absorbers with a similar crystalline volume fraction were applied. With the increasing RGeH4, the accompanied increase in Ge content of μc-Si1-xGex:H narrowed the bandgap and markedly enhanced the long-wavelength absorption. However, the bias-dependent EQE measurement revealed that too much Ge incorporation in absorber deteriorated carrier collection and cell performance. With the optimization of RH2 and RGeH4, the single-junction μc-Si1-xGex:H cell achieved an efficiency of 5.48%, corresponding to the crystalline volume fraction of 50.5% and Ge content of 13.2 at.%. Compared to μc-Si:H cell, the external quantum efficiency at 800 nm had a relative increase by 33.1%.

  7. The Influence of Pickup Protons, from Interstellar Neutral Hydrogen, on the Propagation of Interplanetary Shocks from the Halloween 2003 Solar Events to ACE and Ulysses: A 3-D MHD Modeling Study

    Science.gov (United States)

    Detman, T. R.; Intriligator, D. S.; Dryer, M.; Sun, W.; Deehr, C. S.; Intriligator, J.

    2012-01-01

    We describe our 3-D, time ]dependent, MHD solar wind model that we recently modified to include the physics of pickup protons from interstellar neutral hydrogen. The model has a time-dependent lower boundary condition, at 0.1 AU, that is driven by source surface map files through an empirical interface module. We describe the empirical interface and its parameter tuning to maximize model agreement with background (quiet) solar wind observations at ACE. We then give results of a simulation study of the famous Halloween 2003 series of solar events. We began with shock inputs from the Fearless Forecast real ]time shock arrival prediction study, and then we iteratively adjusted input shock speeds to obtain agreement between observed and simulated shock arrival times at ACE. We then extended the model grid to 5.5 AU and compared those simulation results with Ulysses observations at 5.2 AU. Next we undertook the more difficult tuning of shock speeds and locations to get matching shock arrival times at both ACE and Ulysses. Then we ran this last case again with neutral hydrogen density set to zero, to identify the effect of pickup ions. We show that the speed of interplanetary shocks propagating from the Sun to Ulysses is reduced by the effects of pickup protons. We plan to make further improvements to the model as we continue our benchmarking process to 10 AU, comparing our results with Cassini observations, and eventually on to 100 AU, comparing our results with Voyager 1 and 2 observations.

  8. Reorientational dynamics of charged and neutral solutes in 1-alkyl-3-methylimidazoilum bis(trifluoromethylsulfonyl)imide ionic liquids: Realization of ionic component of hydrogen bond

    Science.gov (United States)

    Sahu, Prabhat Kumar; Sarkar, Moloy

    2016-05-01

    Role of electrostatic interaction on rotational relaxation dynamics of two charged solutes, sodium 8-methoxypyrene-1,3,6-trisulfonate (MPTS), 1-pyrenesulfonic acid sodium salt (1-PSA) and neutral perylene has been studied in two structurally similar but chemically distinguishable imidazolium-based ionic liquids (ILs). Analysis of the results reveals that rotational relaxation of MPTS is significantly hindered even in the IL where acidic C2-H of the imidazolium moiety is replaced by the methyl group. Moreover, rotational relaxation of neutral perylene is found to be faster than mononegative 1-PSA which is again observed to be faster than that of tri-negative MPTS in the same ILs.

  9. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    Science.gov (United States)

    Alquaity, Awad B. S.; KC, Utsav; Popov, Alber; Farooq, Aamir

    2017-12-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm-1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10-5 cm-1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  10. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad

    2017-11-11

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  11. Influence of geometrical non-uniformities of LaNi5 metal hydride bed on its structure and heat and mass transfer at hydrogen absorption

    Science.gov (United States)

    Blinov, D. V.; Dunikov, D. O.; Kazakov, A. N.; Romanov, I. A.

    2017-11-01

    We perform cycling of a 500 g bed of La0.9Ce0.1Ni5 intermetallic compound in vertical and horizontal orientations with measurements of PCT isotherms, and further XRD and SEM investigation of bed structure. Significant decrease in equilibrium absorption pressure is observed in vertical orientation of the bed from 1.58 to 1.36 MPa at 333K, and from 2.68 to 2.51 MPa at 353K, accompanied by evident particle segregation by the bed height and densification at a bottom with formation of a robust agglomerate of small particles (reactor RSP-8 with 1 kg of La0.9Ce0.1Ni5 also show considerable non-uniformity of pressure inside the bed. If the reactor is charged from the top the hydrogen pressure at the bottom is lower on 0.2-0.3 MPa, which results in earlier occurrence of heat and mass transfer crisis.

  12. Tracking Co(I) Intermediate in operando in Photocatalytic Hydrogen Evolution by X-ray transient Absorption Spectroscopy and DFT Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhi-Jun; Zhan, Fei; Xiao, Hongyan; Zhang, Xiaoyi; Kong, Qing-Yu; Fan, Xiang-Bing; Liu, Wen-Qiang; Huang, Mao-Yong; Huang, Cheng; Gao, Yu-Ji; Li, Xu-Bing; Meng, Qing-Yuan; Feng, Ke; Chen, Bin; Tung, Chen-Ho; Zhao, Hai-Feng; Tao, Ye; Wu, Li-Zhu

    2016-12-07

    X-ray transient absorption spectroscopy (XTA) and optical transient spectroscopy (OTA) were used to probe the Co(I) intermediate generated in situ from an aqueous photocatalytic hydrogen evolution system, with [RuII(bpy)3]Cl2·6H2O as the photosensitizer, ascorbic acid/ascorbate as the electron donor, and the Co-polypyridyl complex ([CoII(DPABpy) Cl]Cl) as the pre-catalyst. Upon exposure to light, the XTA measured at Co K-edge visualizes the grow and decay of the Co(I) intermediate, and reveals its Co-N bond contraction of 0.09 ± 0.03 Å. Density functional theory (DFT) calculations support the bond contraction and illustrate that the metal-to-ligand π back-bonding greatly stabilizes the penta-coordinated Co(I) intermediate, which provides easy photon access. To the best of our knowledge, this is the first example of capturing the penta-coordinated Co(I) intermediate in operando with bond contraction by XTA, thereby providing new insights for fundamental understanding of structure– function relationship of cobalt-based molecular catalysts.

  13. The importance of neutral hydrogen for the maintenance of the midlatitude winter nighttime ionosphere: Evidence from IS observations at Kharkiv, Ukraine, and field line interhemispheric plasma model simulations

    Czech Academy of Sciences Publication Activity Database

    Kotov, K. V.; Richards, P. G.; Bogomaz, O. V.; Chernogor, L. F.; Truhlík, Vladimír; Emelyanov, L. Ya.; Chepurnyy, Ya. M.; Domnin, I. F.

    2016-01-01

    Roč. 121, č. 7 (2016), s. 7013-7025 ISSN 2169-9380 Institutional support: RVO:68378289 Keywords : ionosphere * thermosphere * hydrogen * electron density * nighttime Nm F2 enhancement * plasmasphere Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016JA022442/full

  14. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    Hydrogen embrittlement (HE) is a process resulting in a decrease in the fracture toughness or ductility of a metal due to the presence of atomic hydrogen. In addition to pure hydrogen gas as a direct source for the absorption of atomic hydrogen, the damaging effect can manifest itself from other hydrogen-containing gas species such as hydrogen sulfide (H2S), hydrogen chloride (HCl), and hydrogen bromide (HBr) environments. It has been known that H2S environment may result in a much more severe condition of embrittlement than pure hydrogen gas (H2) for certain types of alloys at similar conditions of stress and gas pressure. The reduction of fracture loads can occur at levels well below the yield strength of the material. Hydrogen embrittlement is usually manifest in terms of singular sharp cracks, in contrast to the extensive branching observed for stress corrosion cracking. The initial crack openings and the local deformation associated with crack propagation may be so small that they are difficult to detect except in special nondestructive examinations. Cracks due to HE can grow rapidly with little macroscopic evidence of mechanical deformation in materials that are normally quite ductile. This Technical Memorandum presents a comprehensive review of experimental data for the effects of gaseous Hydrogen Environment Embrittlement (HEE) for several types of metallic materials. Common material screening methods are used to rate the hydrogen degradation of mechanical properties that occur while the material is under an applied stress and exposed to gaseous hydrogen as compared to air or helium, under slow strain rates (SSR) testing. Due to the simplicity and accelerated nature of these tests, the results expressed in terms of HEE index are not intended to necessarily represent true hydrogen service environment for long-term exposure, but rather to provide a practical approach for material screening, which is a useful concept to qualitatively evaluate the severity of

  15. Hydrogen in semiconductors

    CERN Document Server

    Pankove, Jacques I

    1991-01-01

    Hydrogen plays an important role in silicon technology, having a profound effect on a wide range of properties. Thus, the study of hydrogen in semiconductors has received much attention from an interdisciplinary assortment of researchers. This sixteen-chapter volume provides a comprehensive review of the field, including a discussion of hydrogenation methods, the use of hydrogen to passivate defects, the use of hydrogen to neutralize deep levels, shallow acceptors and shallow donors in silicon, vibrational spectroscopy, and hydrogen-induced defects in silicon. In addition to this detailed cove

  16. Impact of hydrogen absorption on crystal structure and magnetic properties of RE.sub.2./sub.T.sub.2./sub.X compounds

    Czech Academy of Sciences Publication Activity Database

    Mašková, S.; Kolomiets, A.; Havela, L.; Andreev, Alexander V.; Svoboda, P.

    2015-01-01

    Roč. 645, Suppl.1 (2015), S76-S79 ISSN 0925-8388. [International Symposium on Metal-Hydrogen Systems (MH14). Salford, 20.07.2014-25.07.2014] Institutional support: RVO:68378271 Keywords : rare earths * hydrogen * metal hydrides * magnetism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.014, year: 2015

  17. High capacity hydrogen storage nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Zidan, Ragaiy; Wellons, Matthew S.

    2017-12-12

    A novel hydrogen absorption material is provided comprising a mixture of a lithium hydride with a fullerene. The subsequent reaction product provides for a hydrogen storage material which reversibly stores and releases hydrogen at temperatures of about 270.degree. C.

  18. Modeling the adsorption of hydrogen, sodium, chloride and phthalate on goethite using a strict charge-neutral ion-exchange theory

    Science.gov (United States)

    Ndu, Udonna

    2017-01-01

    Simultaneous adsorption modeling of four ions was predicted with a strict net charge-neutral ion-exchange theory and its corresponding equilibrium and mass balance equations. An important key to the success of this approach was the proper collection of all the data, particularly the proton adsorption data, and the inclusion of variable concentrations of conjugate ions from the experimental pH adjustments. Using IExFit software, the ion-exchange model used here predicted the competitive retention of several ions on goethite by assuming that the co-adsorption or desorption of all ions occurred in the correct stoichiometries needed to maintain electroneutrality. This approach also revealed that the retention strength of Cl− ions on goethite increases in the presence of phthalate ions. That is, an anion-anion enhancement effect was observed. The retention of Cl− ions was much weaker than phthalate ions, and this also resulted in a higher sensitivity of the Cl− ions toward minor variations in the surface reactivity. The proposed model uses four goethite surface sites. The drop in retention of phthalate ions at low pH was fully described here as resulting from competitive Cl− reactions, which were introduced in increasing concentrations into the matrix as the conjugate base to the acid added to lower the pH. PMID:28464020

  19. Two-fluid (plasma-neutral) Extended-MHD simulations of spheromak configurations in the HIT-SI experiment with PSI-Tet

    Science.gov (United States)

    Sutherland, D. A.; Hansen, C. J.; Jarboe, T. R.

    2017-10-01

    A self-consistent, two-fluid (plasma-neutral) dynamic neutral model has been implemented into the 3-D, Extended-MHD code PSI-Tet. A monatomic, hydrogenic neutral fluid reacts with a plasma fluid through elastic scattering collisions and three inelastic collision reactions: electron-impact ionization, radiative recombination, and resonant charge-exchange. Density, momentum, and energy are evolved for both the plasma and neutral species. The implemented plasma-neutral model in PSI-Tet is being used to simulate decaying spheromak configurations in the HIT-SI experimental geometry, which is being compare to two-photon absorption laser induced fluorescence measurements (TALIF) made on the HIT-SI3 experiment. TALIF is used to measure the absolute density and temperature of monatomic deuterium atoms. Neutral densities on the order of 1015 m-3 and neutral temperatures between 0.6-1.7 eV were measured towards the end of decay of spheromak configurations with initial toroidal currents between 10-12 kA. Validation results between TALIF measurements and PSI-Tet simulations with the implemented dynamic neutral model will be presented. Additionally, preliminary dynamic neutral simulations of the HIT-SI/HIT-SI3 spheromak plasmas sustained with inductive helicity injection will be presented. Lastly, potential benefits of an expansion of the two-fluid model into a multi-fluid model that includes multiple neutral species and tracking of charge states will be discussed.

  20. Ultrafast carrier dynamics unravel role of surface ligands and metal domain size on the photocatalytic hydrogen evolution efficiency of Au-tipped CdS nanorods: an ultrafast transient absorption spectroscopy study

    Science.gov (United States)

    Ben-Shahar, Yuval; Kriegel, Ilka; Scotognella, Francesco; Waiskopf, Nir; Dal Conte, Stefano; Moretti, Luca; Cerullo, Giulio; Rabani, Eran; Banin, Uri

    2017-02-01

    Semiconductor-metal hybrid nanostructures are interesting materials for photocatalysis. Their tunable properties offer a highly controllable platform to design light-induced charge separation, a key to their function in photocatalytic water splitting. Hydrogen evolution quantum yields are influenced by factors as size, shape, material and morphology of the system, additionally the surface coating or the metal domain size play a dominant role. In this paper we present a study on a well-defined model system of Au-tipped CdS nanorods. We use transient absorption spectroscopy to get insights into the charge carrier dynamics after photoexcitation of the bandgap of CdS nanorods. The study of charge transfer processes combined with the hydrogen evolution efficiency unravels the effects of surface coating and the gold tip size on the photocatalytic efficiency. Differences in efficiency with various surface ligands are primarily ascribed to the effects of surface passivation. Surface trapping of charge carriers is competing with effective charge separation, a prerequisite for photocatalysis, leading to the observed lower hydrogen production quantum yields. Interestingly, non-monotonic hydrogen evolution efficiency with size of the gold tip is observed, resulting in an optimal metal domain size for the most efficient photocatalysis. These results are explained by the sizedependent interplay of the metal domain charging and the relative band-alignments. Taken together our findings are of major importance for the potential application of hybrid nanoparticles as photocatalysts.

  1. Questioning hydrogen

    International Nuclear Information System (INIS)

    Hammerschlag, Roel; Mazza, Patrick

    2005-01-01

    As an energy carrier, hydrogen is to be compared to electricity, the only widespread and viable alternative. When hydrogen is used to transmit renewable electricity, only 51% can reach the end user due to losses in electrolysis, hydrogen compression, and the fuel cell. In contrast, conventional electric storage technologies allow between 75% and 85% of the original electricity to be delivered. Even when hydrogen is extracted from gasified coal (with carbon sequestration) or from water cracked in high-temperature nuclear reactors, more of the primary energy reaches the end user if a conventional electric process is used instead. Hydrogen performs no better in mobile applications, where electric vehicles that are far closer to commercialization exceed fuel cell vehicles in efficiency, cost and performance. New, carbon-neutral energy can prevent twice the quantity of GHG's by displacing fossil electricity than it can by powering fuel cell vehicles. The same is true for new, natural gas energy. New energy resources should be used to displace high-GHG electric generation, not to manufacture hydrogen

  2. Beam heating of the neutralizer gas of neutral beam injectors

    International Nuclear Information System (INIS)

    Ott, W.

    1989-02-01

    It was shown by Pamela that the target thickness of the neutralizer gas in neutral beam injectors is smaller than to be expected from gas flow calculations. He explained his findings by direct and indirect beam heating of the gas and a consequent flow acceleration. The role of the neutralizer plasma electrons in the gas heating scenario is reconsidered here. To this end the particle and energy balances of the electrons are solved with allowance for ionization and dissociation of the gas by the electrons. It is shown that the direct contribution of the electrons to heating is not dominant. Their indirect contribution via ion acceleration in the space charge sheath in front of the walls is usually stronger. Methods to increase the neutralizer target thickness are investigated. They are essentially (1) structuring the neutralizer surface in order to reduce the reflection of medium energy particles and to increase the gas accommodation, (2) cooling down the neutralizer to LN 2 -temperature. The scaling of the target thickness with various parameters is investigated and compared with 'cold' flow. Initially it was assumed that the neutralizer plasma electrons are hot and able to excite Balmer alpha radiation in collisions with H 2 molecules. The investigation shows that the electrons must be cold instead (T e + 2 and H + 3 ions leading to excited hydrogen atoms. (orig.)

  3. Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen.

    Science.gov (United States)

    Andersen, J; Voute, A; Mihrin, D; Heimdal, J; Berg, R W; Torsson, M; Wugt Larsen, R

    2017-06-28

    The true global potential energy minimum configuration of the formaldehyde dimer (CH 2 O) 2 , including the presence of a single or a double weak intermolecular CH⋯O hydrogen bond motif, has been a long-standing subject among both experimentalists and theoreticians as two different energy minima conformations of C s and C 2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs. The combination of concentration dependency measurements, observed isotopic spectral shifts associated with H/D substitutions and dedicated annealing procedures, enables the unambiguous assignment of three large-amplitude infrared active hydrogen bond vibrational modes for the non-planar C s configuration of (CH 2 O) 2 embedded in cryogenic neon and enriched para-hydrogen matrices. A (semi)-empirical value for the change of vibrational zero-point energy of 5.5 ± 0.3 kJ mol -1 is proposed for the dimerization process. These THz spectroscopic observations are complemented by CCSD(T)-F12/aug-cc-pV5Z (electronic energies) and MP2/aug-cc-pVQZ (force fields) electronic structure calculations yielding a (semi)-empirical value of 13.7 ± 0.3 kJ mol -1 for the dissociation energy D 0 of this global potential energy minimum.

  4. Methanol absorption characteristics for the removal of H2S (hydrogen sulfide), COS (carbonyl sulfide) and CO2 (carbon dioxide) in a pilot-scale biomass-to-liquid process

    International Nuclear Information System (INIS)

    Seo, Myung Won; Yun, Young Min; Cho, Won Chul; Ra, Ho Won; Yoon, Sang Jun; Lee, Jae Goo; Kim, Yong Ku; Kim, Jae Ho; Lee, See Hoon; Eom, Won Hyun; Lee, Uen Do; Lee, Sang Bong

    2014-01-01

    The BTL (biomass-to-liquid) process is an attractive process that produces liquid biofuels from biomass. The FT (Fisher–Tropsch) process is used to produce synfuels such as diesel and gasoline from gasified biomass. However, the H 2 S (hydrogen sulfide), COS (carbonyl sulfide) and CO 2 (carbon dioxide) in the syngas that are produced from the biomass gasifiers cause a decrease of the conversion efficiency and deactivates the catalyst that is used in the FT process. To remove the acid gases, a pilot-scale methanol absorption tower producing diesel at a rate of 1 BPD (barrel per day) was developed, and the removal characteristics of the acid gases were determined. A total operation time of 500 h was achieved after several campaigns. The average syngas flow rate at the inlet of methanol absorption tower ranged from 300 to 800 L/min. The methanol absorption tower efficiently removed H 2 S from 30 ppmV to less than 1 ppmV and COS from 2 ppmV to less than 1 ppmV with a removal of CO 2 from 20% to 5%. The outlet gas composition adhered to the guidelines for FT reactors. No remaining sulfurous components were found, and the tar component was analyzed in the spent methanol after long-term operations. - Highlights: • The gas cleaning system in a pilot-scale BTL (biomass-to-liquid) process is reported. • Although methanol absorption tower is conventional process, its application to BTL process is attempted. • The methanol absorption tower efficiently removed H 2 S, COS and CO 2 in the syngas. • The sulfurous and tar components in the methanol are analyzed

  5. Predicting laser-induced bulk damage and conditioning for deuterated potassium di-hydrogen phosphate crystals using ADM (absorption distribution model)

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Z M; Spaeth, M L; Manes, K; Adams, J J; Carr, C W

    2010-02-26

    We present an empirical model that describes the experimentally observed laser-induced bulk damage and conditioning behavior in deuterated Potassium dihydrogen Phosphate (DKDP) crystals in a self-consistent way. The model expands on an existing nanoabsorber precursor model and the multi-step absorption mechanism to include two populations of absorbing defects, one with linear absorption and another with nonlinear absorption. We show that this model connects previously uncorrelated small-beam damage initiation probability data to large-beam damage density measurements over a range of ns pulse widths relevant to ICF lasers such as the National Ignition Facility (NIF). In addition, this work predicts the damage behavior of laser-conditioned DKDP and explains the upper limit to the laser conditioning effect. The ADM model has been successfully used during the commissioning and early operation of the NIF.

  6. EXCITATION TEMPERATURE OF THE WARM NEUTRAL MEDIUM AS A NEW PROBE OF THE Lyα RADIATION FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Claire E.; Lindner, Robert R.; Stanimirović, Snežana; Pingel, Nickolas M.; Lawrence, Allen; Babler, Brian L. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Goss, W. M.; Jencson, Jacob [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville, Socorro, NM 87801 (United States); Heiles, Carl [Radio Astronomy Laboratory, UC Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States); Dickey, John [University of Tasmania, School of Maths and Physics, Private Bag 37, Hobart, TAS 7001 (Australia); Hennebelle, Patrick, E-mail: cmurray@astro.wisc.edu [Laboratoire AIM, Paris-Saclay, CEA/IRFU/SAp—CNRS—Université Paris Diderot, F-91191 Gif-sur-Yvette Cedex (France)

    2014-02-01

    We use the Karl G. Jansky Very Large Array to conduct a high-sensitivity survey of neutral hydrogen (H I) absorption in the Milky Way. In combination with corresponding H I emission spectra obtained mostly with the Arecibo Observatory, we detect a widespread warm neutral medium component with excitation temperature 〈T{sub s}〉=7200{sub −1200}{sup +1800} K (68% confidence). This temperature lies above theoretical predictions based on collisional excitation alone, implying that Lyα scattering, the most probable additional source of excitation, is more important in the interstellar medium (ISM) than previously assumed. Our results demonstrate that H I absorption can be used to constrain the Lyα radiation field, a critical quantity for studying the energy balance in the ISM and intergalactic medium yet notoriously difficult to model because of its complicated radiative transfer, in and around galaxies nearby and at high redshift.

  7. Numerical simulation of absorption-desorption cyclic processes for metal-hydrogen reactor with heat recovery using phase-change material

    International Nuclear Information System (INIS)

    Ben Mâad, Hatem; Miled, Amel; Askri, Faouzi; Ben Nasrallah, Sassi

    2016-01-01

    Highlights: • A metal hydride reactor equipped with a PCM was numerically investigated. • A model was developed to account for the equations of heat and mass transfer in PCM. • The liquid fraction in PCM was described by an approximation of Heaviside function. • The use of an unstructured CVFEM to discretize the governing equations. • The prediction of thermal coupling process between the hydride bed and the PCM domain. - Abstract: In this paper a transient two-dimensional mathematical model was developed for predicting the coupled heat and mass transfer within a metal-hydrogen reactor equipped with a phase change material (MHR-PCM for short). For this model, the liquid fraction in the PCM was described by an analytic approximation of the Heaviside step function which, to the knowledge of the authors, is applied for the first time to study phase-change problems. The unstructured control volume finite element method was used to discretize the governing equations and a computer code was developed on Fortran 90 to solve the obtained algebraic equations. The numerical model has been validated by comparison with experimental data and exploited to predict the thermal coupling process between the hydride bed and the PCM domain. The obtained numerical results revealed that the thermal energy stored by the PCM, when the metal-hydrogen reactor reaches 97% of its maximum capacity of hydrogen storage, can evacuate up to 80% of the hydrogen stored in the reactor.

  8. Cosmology: Photons from dwarf galaxy zap hydrogen

    Science.gov (United States)

    Erb, Dawn K.

    2016-01-01

    The detection of photons sufficiently energetic to ionize neutral hydrogen, coming from a compact, star-forming galaxy, offers clues to how the first generation of galaxies may have reionized hydrogen gas in the early Universe. See Letter p.178

  9. Evaluation of Detrimental Effects on Mechanical Properties of Zry-4 Due to Hydrogen Absorption by means of Scanning Electron Microscopy (SEM) In-Situ Observation of Crack Propagation

    International Nuclear Information System (INIS)

    Fernandez, L; Fernandez, G.E; Bertolino, G; Meyer, G

    2001-01-01

    The study of mechanical properties degradation of zirconium alloys due to hydrides assumes fundamental importance in the nuclear industry.During normal nuclear reactors operation, structural parts absorbed hydrogen generated from radiolysis of water, causing detrimental effects on mechanical properties.As a consequence, these materials are easily cracked in the presence of mechanical solicitation due to loss of ductility of the hydride-phase.The presence of cracks indicates fracture mechanic as the most suitable methodology in the study of mechanical properties degradation.In this work we used the crack tip opening displacement (CTOD) criteria to evaluate the detrimental effects on mechanical properties with the observation in SEM of crack propagation.The samples used were SEN (B) of Zry-4 and cathodic homogenous charged with hydrogen concentrations lower than 400 ppm

  10. Neutral polypropylene laser welding

    Science.gov (United States)

    Mandolfino, Chiara; Lertora, Enrico; Gambaro, Carla

    2016-10-01

    The joining of polymeric materials is a technology used in many industrial applications, from transport to telecommunications and the medical sector. A new technology for the joining of polymers is the laser welding process. In particular, fibre laser welding is a flexible technology which allows high process speed and the realization of good quality joints. Despite its application becoming more widespread in the production of assemblies of high precision, the application of laser technology for the welding of polymers has not been the subject of many studies up to now. This study focused on the welding of neutral polypropylene. The window process parameter was identified, without the use of additives to increase radiation absorption, and a mechanical characterization was conducted in order to evaluate the quality of the joints realized.

  11. Modeling Secondary Neutral Helium in the Heliosphere

    International Nuclear Information System (INIS)

    Müller, Hans-Reinhard; Möbius, Eberhard; Wood, Brian E.

    2016-01-01

    An accurate, analytic heliospheric neutral test-particle code for helium atoms from the interstellar medium (ISM) is coupled to global heliospheric models dominated by hydrogen and protons from the solar wind and the ISM. This coupling enables the forward-calculation of secondary helium neutrals from first principles. Secondaries are produced predominantly in the outer heliosheath, upwind of the heliopause, by charge exchange of helium ions with neutral atoms. The forward model integrates the secondary production terms along neutral trajectories and calculates the combined neutral helium phase space density in the innermost heliosphere where it can be related to in-situ observations. The phase space density of the secondary component is lower than that of primary neutral helium, but its presence can change the analysis of primaries and the ISM, and can yield valuable insight into the characteristics of the plasma in the outer heliosheath. (paper)

  12. Neutral hydrogen in elliptical and IO galaxies

    International Nuclear Information System (INIS)

    Bottinelli, L.; Gouguenheim, L.

    1979-01-01

    New HI detections have been obtained using the Nancay radiotelescope for NGC 2974 and 3962. These results and the large scale distribution obtained for NGC 3962 indicate that the HI-rich elliptical galaxies exhibit common properties which are not easily explained by accretion of an intergalactic cloud. The field aroud NGC 1052 has been mapped and there is an HI connection with the neighbouring galaxies. The HI content of several IO galaxies indicates that the galaxies which are members of groups are relatively HI-rich; this could be produced by additional HI coming from companion galaxies [fr

  13. Hydrogen Materials Compatibility in Piezoelectrics

    Science.gov (United States)

    Alvine, Kyle; Pitman, Stan; Henager, Charles; Shutthanandan, Vaithiyalingam; Brown, Craig; Tyagi, Madhu; Jenkins, Tim; Udovic, Terry

    2010-03-01

    Hydrogen materials compatibility is an important materials science issue for hydrogen storage and delivery in hydrogen vehicle technology and infrastructure and to a lesser degree the microelectronics industry where hydrogen passivation is required. Piezoelectrics are one such material. They are used in direct injection hydrogen internal combustion engines (H2ICE) as actuators but tend to foul rapidly in high pressure hydrogen. Ferroelectric random access memory (FERAM) also suffers similar degradation issues. We present high pressure hydrogen absorption and diffusion findings for PZT and BaTiO3 piezoelectric materials. Data is based on quasi-elastic neutron (QENS) scattering and elastic recoil detection analysis (ERDA).

  14. Spectroscopic studies of hydrogen collisions

    International Nuclear Information System (INIS)

    Kielkopf, J.

    1991-01-01

    Low energy collisions involving neutral excited states of hydrogen are being studied with vacuum ultraviolet spectroscopy. Atomic hydrogen is generated by focusing an energetic pulse of ArF, KrF, or YAG laser light into a cell of molecular hydrogen, where a plasma is created near the focal point. The H 2 molecules in and near this region are dissociated, and the cooling atomic hydrogen gas is examined with laser and dispersive optical spectroscopy. In related experiments, we are also investigating neutral H + O and H + metal - atom collisions in these laser-generated plasmas

  15. What is Neutrality?

    NARCIS (Netherlands)

    Pierik, R.; van der Burg, W.

    2014-01-01

    This paper reinvestigates the question of liberal neutrality. We contend that current liberal discussions have been dominated - if not hijacked - by one particular interpretation of what neutrality could imply, namely, exclusive neutrality, that aims to exclude religious and cultural expressions

  16. Interstellar absorption lines in high-resolution IUE spectra of cataclysmic variables

    International Nuclear Information System (INIS)

    Mauche, C.W.; Raymond, J.C.; Cordova, F.A.

    1988-01-01

    High-resolution ultraviolet spectra of five cataclysmic variables obtained with the IUE are used to investigate the character of the interstellar medium in the vicinity of the sun. These spectra reveal narrow absorption features of neutral and singly ionized interstellar species, and, in SS Cyg, narrow velocity-shifted absorption features of C IV, Si IV, and Si III. Using the column densities implied by the absorption features of the neutral and singly ionized species, values for the depletion of Si, Mg, Mn, and Fe from the gas phase of the interstellar medium in the vicinity of the sun are obtained. These hydrogen column densities are of particular importance in constraining the soft X-ray luminosity of cataclysmic variables because of the severe attenuation of the soft X-ray flux of cataclysmic variables by photoelectric absorption in the interstellar medium. In addition, using the column densities implied by the absorption features of C IV, Si IV, and Si III in the spectrum of SS Cyg, the existence of an expanding H II region of interstellar gas photoionized by he EUV and soft X-ray flux of this cataclysmic variable are inferred. 78 references

  17. Deciphering Galactic Hydrogen with 21-SPONGE

    Science.gov (United States)

    Murray, Claire; Stanimirovic, Snezana; Goss, Miller; Heiles, Carl E.; Miller Dickey, John; Lindner, Robert; Babler, Brian L.

    2017-01-01

    Neutral hydrogen (HI) in the interstellar medium (ISM) is crucial to the life cycles of galaxies. The balance between disparate phases of HI -- including the cold neutral (CNM) and warm neutral (WNM) medium -- governs the formation of dense, star-forming material, and reflects the nature of feedback in galaxies. To probe the multi-phase structure of HI, we present results from 21-SPONGE: the largest and most sensitive survey for Galactic HI absorption ever at the Karl G. Jansky Very Large Array (VLA). Complemented by HI emission from the Arecibo Observatory, 21-SPONGE is uniquely sensitive to CNM and WNM temperatures from 10-104 K and column densities from 1018-1022 cm-2. Despite our unprecedented sensitivity, the maximum temperature we detect for individual spectral lines is Ts~1500 K, although stacking analysis of 21-SPONGE absorption lines indicates the presence of pervasive, high-Ts WNM population with Ts~7000 K. To understand the physics underlying these results, we developed Autonomous Gaussian Decomposition (AGD), a Python-based tool for efficiently and objectively analyzing spectral lines. By applying AGD to 21-SPONGE and 1000s of synthetic HI spectra from 3D numerical simulations, we correct our measurements for completeness and observational biases. We further prove that we can successfully recover the temperatures and densities of real clouds along simulated lines of sight. In addition, we show that absorption line shapes are sensitive to the strength and topology of the Lyman alpha radiation field and its role in HI excitation, which are poorly-constrained yet important for understanding the energy balance of the ISM. Our results are among the first to statistically quantify the success of observational methods at reproducing true HI properties, and represent crucial steps towards understanding the role of HI in star formation.

  18. Ultrasonic absorption

    International Nuclear Information System (INIS)

    Beyer, R.T.

    1985-01-01

    The paper reviews studies of ultrasonic absorption in liquid alkali metals. The experimental methods to measure the absorption coefficients are briefly described. Experimental results reported for the liquid metals: sodium, potassium, rubidium and caesium, at medium temperatures, are presented, as well as data for liquid alloys. Absorption losses due to the presence of an external magnetic field, and the effects of viscosity on the absorption in metals, are both discussed. (U.K.)

  19. Micropolarity and Hydrogen-Bond Donor Ability of Environmentally Friendly Anionic Reverse Micelles Explored by UV/Vis Absorption of a Molecular Probe and FTIR Spectroscopy.

    Science.gov (United States)

    Girardi, Valeria R; Silber, Juana J; Falcone, Ruben Darío; Correa, N Mariano

    2018-02-08

    In the present work we show how two biocompatible solvents, methyl laurate (ML) and isopropyl myristate (IPM), can be used as a less toxic alternative to replace the nonpolar component in a sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) formulation. In this sense, the micropolarity and the hydrogen-bond ability of the interface were monitored through the use of the solvatochromism of a molecular probe (1-methyl-8-oxyquinolinium betaine, QB) and Fourier transform infrared spectroscopy (FTIR). Our results demonstrate that the micropolarity sensed by QB in ML RMs is lower than in IPM RMs. Additionally, the water molecules form stronger H-bond interactions with the polar head of AOT in ML than in IPM. By FTIR was revealed that more water molecules interact with the interface in ML/AOT RMs. On the other hand, for AOT RMs generated in IPM, the weaker water-surfactant interaction allows the water molecules to establish hydrogen bonds with each other trending to bulk water more easily than in ML RMs, a consequence of the dissimilar penetration of nonpolar solvents into the interfacial region. The penetration process is strongly controlled by the polarity and viscosity of the external solvents. All of these results allow us to characterize these biocompatible systems, providing information about interfacial properties and how they can be altered by changing the external solvent. The ability of the nontoxic solvent to penetrate or not into the AOT interface produces a new interface with attractive properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Hydrogen-Mediated Electron Doping of Gold Clusters As Revealed by In Situ X-ray and UV-vis Absorption Spectroscopy.

    Science.gov (United States)

    Ishida, Ryo; Hayashi, Shun; Yamazoe, Seiji; Kato, Kazuo; Tsukuda, Tatsuya

    2017-06-01

    We previously reported that small (∼1.2 nm) gold clusters stabilized by poly(N-vinyl-2-pyrrolidone) (Au:PVP) exhibited a localized surface plasmon resonance (LSPR) band at ∼520 nm in the presence of NaBH 4 . To reveal the mechanism of this phenomenon, the electronic structure of Au:PVP during the reaction with NaBH 4 in air was examined by means of in situ X-ray absorption spectroscopy at Au L 3 -edge and UV-vis spectroscopy. These measurements indicated that the appearance of the LSPR band is not associated with the growth in size but is ascribed to electron doping to the Au sp band by the adsorbed H atoms.

  1. Hydrogen production using ammonia borane

    Science.gov (United States)

    Hamilton, Charles W; Baker, R. Thomas; Semelsberger, Troy A; Shrestha, Roshan P

    2013-12-24

    Hydrogen ("H.sub.2") is produced when ammonia borane reacts with a catalyst complex of the formula L.sub.nM-X wherein M is a base metal such as iron, X is an anionic nitrogen- or phosphorus-based ligand or hydride, and L is a neutral ancillary ligand that is a neutral monodentate or polydentate ligand.

  2. Spatial Variability in the Ratio of Interstellar Atomic Deuterium to Hydrogen. II. Observations toward γ2 Velorum and ζ Puppis by the Interstellar Medium Absorption Profile Spectrograph

    Science.gov (United States)

    Sonneborn, George; Tripp, Todd M.; Ferlet, Roger; Jenkins, Edward B.; Sofia, U. J.; Vidal-Madjar, Alfred; Woźniak, Prezemysław R.

    2000-12-01

    High-resolution far-ultraviolet spectra of the early-type stars γ2 Vel and ζ Pup were obtained to measure the interstellar deuterium abundances in these directions. The observations were made with the Interstellar Medium Absorption Profile Spectrograph (IMAPS) during the ORFEUS-SPAS II mission in 1996. IMAPS spectra cover the wavelength range 930-1150 Å with λ/Δλ~80,000. The interstellar D I features are resolved and cleanly separated from interstellar H I in the Lyδ and Lyɛ profiles of both sight lines and also in the Lyγ profile of ζ Pup. The D I profiles were modeled using a velocity template derived from several N I lines in the IMAPS spectra recorded at higher signal-to-noise ratio. To find the best D I column density, we minimized χ2 for model D I profiles that included not only the N(D I) as a free parameter, but also the effects of several potential sources of systematic error, which were allowed to vary as free parameters. H I column densities were measured by analyzing Lyα absorption profiles in a large number of IUE high-dispersion spectra for each of these stars and applying this same χ2-minimization technique. Ultimately we found that D/H=2.18+0.36-0.31×10-5 for γ2 Vel and 1.42+0.25-0.23×10-5 for ζ Pup, values that contrast markedly with D/H derived in Paper I for δ Ori A (the stated errors are 90% confidence limits). Evidently, the atomic D/H ratio in the ISM, averaged over path lengths of 250-500 pc, exhibits significant spatial variability. Furthermore, the observed spatial variations in D/H do not appear to be anticorrelated with N/H, one measure of heavy-element abundances. We briefly discuss some hypotheses to explain the D/H spatial variability. Within the framework of standard big bang nucleosynthesis, the large value of D/H found toward γ2 Vel is equivalent to a cosmic baryon density of ΩBh2=0.023+/-0.002, which we regard as an upper limit since there is no correction for the destruction of deuterium in stars. This paper is

  3. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint)

    National Research Council Canada - National Science Library

    Walker, Quentin E; Cappelli, Mark A; Hargus, William A

    2007-01-01

    ... to a surrogate anode from the plume of low power arcjets operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster-arcjet neutralizer package...

  4. Results from neutral kaon regeneration at high energies

    International Nuclear Information System (INIS)

    Hladky, J.

    1976-01-01

    Experimental neutral kaon regeneration results at Serpukhov energies up to 50 GeV are presented, including the coherent regeneration on hydrogen, deuterium and carbon regenerators and elastic regeneration on deuterium and carbon regenerators. (author)

  5. Effect of the hydrogen absorption on the plastic deformation localization of a 316L stainless steel; Effet de l'absorption d'hydrogene sur la localisation de la deformation plastique d'un acier inoxydable 316L

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, I. [Bordeaux Univ., Lab. de Mecanique Physique, CNRS, 33 (France)

    2007-07-01

    This study is realized in the context of the aging evaluation resulting from the coupling between a mechanical constraint and corrosive conditions, as the stress corrosion or the fatigue corrosion. In this study the authors evaluate quantitatively the hydrogen effect on the plasticity at the grain scale. (A.L.B.)

  6. Infrared absorption of trans-1-chloromethylallyl and trans-1-methylallyl radicals produced in photochemical reactions of trans-1,3-butadiene and Cl2 in solid para-hydrogen.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Jen-Yu; Tanaka, Keiichi; Lee, Yuan-Pern

    2012-08-28

    The reactions of chlorine and hydrogen atoms with trans-1,3-butadiene in solid para-hydrogen (p-H(2)) were investigated with infrared (IR) absorption spectra. When a p-H(2) matrix containing Cl(2) and trans-1,3-butadiene was irradiated with ultraviolet light at 365 nm, intense lines at 650.3, 809.0, 962.2, 1240.6 cm(-1), and several weaker ones due to the trans-1-chloromethylallyl radical, ●(CH(2)CHCH)CH(2)Cl, appeared. Observed wavenumbers and relative intensities agree with the anharmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++g(2d, 2p) method. That the Cl atom adds primarily to the terminal carbon atom of trans-1,3-butadiene is in agreement with the path of minimum energy predicted theoretically, but in contrast to the reaction of Cl + propene in solid p-H(2) [J. Amicangelo and Y.-P. Lee, J. Phys. Chem. Lett. 1, 2956 (2010)] in which the addition of Cl to the central C atom is favored, likely through steric effects in a p-H(2) matrix. A second set of lines, intense at 781.6, 957.9, 1433.6, 2968.8, 3023.5, 3107.3 cm(-1), were observed when the UV-irradiated Cl(2)/trans-1,3-butadiene/p-H(2) matrix was further irradiated with IR light from a SiC source. These lines are assigned to the trans-1-methylallyl radical, ●(CH(2)CHCH)CH(3), produced from reaction of 1,3-butadiene with a H atom resulted from the reaction of Cl atoms with solid p-H(2) exposed to IR radiation.

  7. Infrared absorption spectra of partially deuterated methoxy radicals CH2DO and CHD2O isolated in solid para-hydrogen.

    Science.gov (United States)

    Haupa, Karolina A; Johnson, Britta A; Sibert, Edwin L; Lee, Yuan-Pern

    2017-10-21

    The investigation of partially deuterated methoxy radicals is important because the symmetry lowering from C 3v to C s provides new insights into the couplings between rovibronic states via Jahn-Teller and spin-orbit interactions. The vibrational spectrum of the partially deuterated methoxy radical CH 2 DO in a matrix of p-H 2 has been recorded. This species was prepared by irradiating a p-H 2 matrix containing deuterated d 1 -nitritomethane (CH 2 DONO) at 3.3 K with laser light at 355 nm. The identification of the radical is based on the photochemical behavior of the precursor and comparison of observed vibrational wavenumbers and infrared (IR) intensities with those predicted from a refined quartic, curvilinear, internal coordinate force field calculated with the coupled-cluster singles and doubles with perturbative triples/cc-pVTZ method. CH 2 DO reacts with H 2 with a rate coefficient (3.5 ± 1.0) × 10 -3 s -1 . Predominantly c-CHDOH and a negligibly small amount of t-CHDOH were produced. This stereoselectivity results from the reaction H + C s -CH 2 DOH, which was demonstrated by an additional experiment on irradiation of a CH 2 DOH/Cl 2 /p-H 2 matrix with ultraviolet and IR light to induce the H + CH 2 DOH reaction; only c-CHDOH was observed from this experiment. Even though the energies of transition states and products for the formation of c-CHDOH and t-CHDOH differ by only ∼10 cm -1 , the selective formation of c-CHDOH can be explained by tunneling of the hydrogen atom via an optimal tunneling path. Similarly, the vibronic spectrum for the partially deuterated specie d 2 -methoxy radical (CHD 2 O) was obtained upon irradiation of d 2 -nitritomethane (CHD 2 ONO) at 355 nm. Lines associated with the fundamental vibrational modes were observed and assigned; line positions agree with theoretically predicted vibrational wavenumbers. CHD 2 O reacts with H 2 with a rate coefficient (6.0 ± 1.4) × 10 -3 s -1 ; CD 2 OH was produced as a major product because

  8. How far can a single hydrogen bond tune the spectral properties of the GFP chromophore?

    DEFF Research Database (Denmark)

    Kiefer, Hjalte; Lattouf, Elie; Persen, Natascha Wardinghus

    2015-01-01

    Photoabsorption of the hydrogen-bonded complex of a neutral and an anionic Green Fluorescent Protein chromophore has been studied using a new dual-detection approach to action-absorption spectroscopy. Following absorption of one photon, dissociation through a single channel ensures that the full...... time, the apparent effect of the H-bond for the neutral chromophore is as large as 0.5 eV, red-shifting the absorption maximum of the isolated neutral (340 nm) to that measured in the dimer (393 nm) and various proteins ([similar]395 nm). This shift results from changes in the topography of potential...... absorption spectrum is measured. Our theoretical account of the spectral shape reveals that the anionic 0–0 transition (464 nm) is blue-shifted compared to that of the wild-type protein (478 nm) due to the stronger H-bond in the dimer, and represents an upper bound for that of the isolated anion. At the same...

  9. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Pedersen, Allan Schrøder; Kjøller, John; Larsen, B.

    1983-01-01

    A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast at tempe......A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast...

  10. 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.

  11. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  12. Towards a Revised Monte Carlo Neutral Particle Surface Interaction Model

    International Nuclear Information System (INIS)

    Stotler, D.P.

    2005-01-01

    The components of the neutral- and plasma-surface interaction model used in the Monte Carlo neutral transport code DEGAS 2 are reviewed. The idealized surfaces and processes handled by that model are inadequate for accurately simulating neutral transport behavior in present day and future fusion devices. We identify some of the physical processes missing from the model, such as mixed materials and implanted hydrogen, and make some suggestions for improving the model

  13. Neutral Particle Analyzer Measurements of Ion Behavior in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    S.S. Medley; R.E. Bell; D.S. Darrow; A.L. Roquemore

    2002-02-06

    Initial results obtained with the Neutral Particle Analyzer (NPA) diagnostic on the National Spherical Torus Experiment (NSTX) are presented. Magnetohydrodynamic activity and reconnection events cause depletion of the deuterium energetic ion distribution created by neutral-beam injection. Adding High Harmonic Fast Wave Heating to neutral-beam-heated discharges results in the generation of an energetic ion tail above the beam injection energy. NPA measurements of the residual hydrogen ion temperature are in good agreement with those from recombination spectroscopy.

  14. Truly neutral microobjects and oscillations in particle physics

    International Nuclear Information System (INIS)

    Bilenky, S.M.; Pontecorvo, B.

    1982-01-01

    Oscillation phenomena between different states of neutral elementary particles are discussed. The known kaon oscillation and the proposed neutrino, neutron and other kinds of oscillations are analysed. The proper bound states of neutral objects (neutrinos, neutrons, hydrogen atoms) are investigated in the case of small and strong violation of CP symmetry. Consequences concerning the observable masses and quantum numbers of such neutral objects are drawn. (D.Gy.)

  15. Thermophysics Characterization of Multiply Ionized Air Plasma Absorption of Laser Radiation

    Science.gov (United States)

    Wang, Ten-See; Rhodes, Robert; Turner, Jim (Technical Monitor)

    2002-01-01

    The impact of multiple ionization of air plasma on the inverse Bremsstrahlung absorption of laser radiation is investigated for air breathing laser propulsion. Thermochemical properties of multiply ionized air plasma species are computed for temperatures up to 200,000 deg K, using hydrogenic approximation of the electronic partition function; And those for neutral air molecules are also updated for temperatures up to 50,000 deg K, using available literature data. Three formulas for absorption are calculated and a general formula is recommended for multiple ionization absorption calculation. The plasma composition required for absorption calculation is obtained by increasing the degree of ionization sequentially, up to quadruple ionization, with a series of thermal equilibrium computations. The calculated second ionization absorption coefficient agrees reasonably well with that of available data. The importance of multiple ionization modeling is demonstrated with the finding that area under the quadruple ionization curve of absorption is found to be twice that of single ionization. The effort of this work is beneficial to the computational plasma aerodynamics modeling of laser lightcraft performance.

  16. Neutral Buoyancy Laboratory (NBL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility,...

  17. CO2-neutral fuels

    Science.gov (United States)

    Goede, A. P. H.

    2015-08-01

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

  18. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

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

  19. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  20. Neutral beams for magnetic fusion

    International Nuclear Information System (INIS)

    Hooper, B.

    1977-01-01

    Significant advances in forming energetic beams of neutral hydrogen and deuterium atoms have led to a breakthrough in magnetic fusion: neutral beams are now heating plasmas to thermonuclear temperatures, here at LLL and at other laboratories. For example, in our 2XIIB experiment we have injected a 500-A-equivalent current of neutral deuterium atoms at an average energy of 18 keV, producing a dense plasma (10 14 particles/cm 3 ) at thermonuclear energy (14 keV or 160 million kelvins). Currently, LLL and LBL are developing beam energies in the 80- to 120-keV range for our upcoming MFTF experiment, for the TFTR tokamak experiment at Princeton, and for the Doublet III tokamak experiment at General Atomic. These results increase our long-range prospects of producing high-intensity beams of energies in the hundreds or even thousands of kilo-electron-volts, providing us with optimistic extrapolations for realizing power-producing fusion reactors

  1. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. Nor...... do we fully realize how we might have changed as we return for the fictional worlds we have visited. The feeling of being absorbed is one of the most illusive and transient feelings, but also one that motivates audiences to spend considerable amounts of time in narrative worlds, and one...... that is central to our understanding of the effects of narratives on beliefs and behavior. Key specialists inform the reader of this book about the nature of the peculiar state of consciousness during episodes of absorption, the perception of absorption in history, the role of absorption in meaningful experiences...

  2. Study of neutral particles

    International Nuclear Information System (INIS)

    Bartel, W.; Bulos, F.; Eisner, A.

    1975-01-01

    The range of physics problems for which a detector emphasizing neutrals is most suitable is discussed. The primary goals are the all neutrals cross section, sigma/sub o/ (e + e - → neutrals), the characterization of the neutral energy in multi-hadronic events, the search for monoenergetic photons, and good sensitivity in the difficult region of low energy photons. Those features of multi-hadronic events which are most relevant to a neutral detector were calculated using a jet model with parameters extrapolated from SPEAR energies. These distributions are presented and discussed

  3. Hydrogen Sorption Performance of Pure Magnesium during Continued Cycling

    DEFF Research Database (Denmark)

    Vigeholm, B.; Kjøller, John; Larsen, B.

    1983-01-01

    Preliminary investigations of the hydrogen absorption - desorption by commercially pure magnesium powder under continuous operation show little or no reduction in hydrogen capacity up to 70 cycles and high temperature exposure exceeding 1200 h. Absorption was studied at 260°–425°C and hydrogen...

  4. Catalytic activity of noble metals promoting hydrogen uptake

    NARCIS (Netherlands)

    Borgschulte, A.; Westerwaal, R.J.; Rector, J.H.; Schreuders, H.; Dam, B.; Griessen, R.P.

    2006-01-01

    The engineering of pure and metal alloy catalysts for hydrogen absorption is needed to improve the kinetics of hydrogen-related devices. We introduce a new route to search for alloys that can yield superior catalytic behavior for hydrogen absorption, using an optical technique to measure the

  5. X-ray Absorption Spectroscopy and Density Functional Theory Studies of [(H3buea)FeIII-X]n1 (X= S2-, O2-,OH-): Comparison of Bonding and Hydrogen Bonding in Oxo and Sulfido Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Abhishek; Hocking, Rosalie K.; /Stanford U., Chem. Dept.; Larsen, Peter; Borovik, Andrew S.; /Kansas U.; Hodgson, Keith O.; Hedman, Britt; Solomon, Edward I.; /SLAC,

    2006-09-27

    Iron L-edge, iron K-edge, and sulfur K-edge X-ray absorption spectroscopy was performed on a series of compounds [Fe{sup III}H{sub 3}buea(X)]{sup n-} (X = S{sup 2-}, O{sup 2-}, OH{sup -}). The experimentally determined electronic structures were used to correlate to density functional theory calculations. Calculations supported by the data were then used to compare the metal-ligand bonding and to evaluate the effects of H-bonding in Fe{sup III}-O vs Fe{sup III-}S complexes. It was found that the Fe{sup III-}O bond, while less covalent, is stronger than the FeIII-S bond. This dominantly reflects the larger ionic contribution to the Fe{sup III-}O bond. The H-bonding energy (for three H-bonds) was estimated to be -25 kcal/mol for the oxo as compared to -12 kcal/mol for the sulfide ligand. This difference is attributed to the larger charge density on the oxo ligand resulting from the lower covalency of the Fe-O bond. These results were extended to consider an Fe{sup IV-}O complex with the same ligand environment. It was found that hydrogen bonding to Fe{sup IV-}O is less energetically favorable than that to Fe{sup III-}O, which reflects the highly covalent nature of the Fe{sup IV-}O bond.

  6. PDX neutral-beam reionization losses

    International Nuclear Information System (INIS)

    Kugel, H.W.; Dylla, H.F.; Eubank, H.P.; Kozub, T.A.; Moore, R.; Schilling, G.; Stewart, L.D.; von Halle, A.; Williams, M.D.

    1982-02-01

    Reionization losses for 1.5 MW H 0 and 2 MW D 0 neutral beams injected into the PDX tokamak were studied using pressure gauges, photo-transistors, thermocouples, surface shielding, and surface sample analysis. Considerable outgassing of conventionally prepared 304SS ducts occurred during initial injections and gradually decreased with the cumulative absorption of beam power. Reionization power losses are presently about 5% in the ducts and about 12% total for a beamline including the duct. Present duct pressures are attributed primarily to gas from the ion source and neutralizer with much smaller contributions from residual wall desorption. Physical mechanisms for the observed duct outgassing are discussed

  7. Neutral Particle Analyzer Diagnostic on NSTX

    Energy Technology Data Exchange (ETDEWEB)

    S.S. Medley; A.L. Roquemore

    2004-03-16

    The Neutral Particle Analyzer (NPA) diagnostic on the National Spherical Torus Experiment (NSTX) utilizes a PPPL-designed E||B spectrometer that measures the energy spectra of minority hydrogen and bulk deuterium species simultaneously with 39 energy channels per mass specie and a time resolution of 1 ms. The calibrated energy range is E = 0.5-150 keV and the energy resolution varies from AE/E = 3-7% over the surface of the microchannel plate detector.

  8. Neutral Particle Analyzer Diagnostic on NSTX

    International Nuclear Information System (INIS)

    Medley, S.S.; Roquemore, A.L.

    2004-01-01

    The Neutral Particle Analyzer (NPA) diagnostic on the National Spherical Torus Experiment (NSTX) utilizes a PPPL-designed E||B spectrometer that measures the energy spectra of minority hydrogen and bulk deuterium species simultaneously with 39 energy channels per mass specie and a time resolution of 1 ms. The calibrated energy range is E = 0.5-150 keV and the energy resolution varies from AE/E = 3-7% over the surface of the microchannel plate detector

  9. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  10. Hydrogenation apparatus

    Science.gov (United States)

    Friedman, Joseph [Encino, CA; Oberg, Carl L [Canoga Park, CA; Russell, Larry H [Agoura, CA

    1981-01-01

    Hydrogenation reaction apparatus comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1100.degree. to 1900.degree. C., while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products.

  11. 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

  12. Neutral surfaces in neutral four-spaces

    Directory of Open Access Journals (Sweden)

    Gary Jensen

    1990-11-01

    Full Text Available Properties of the Gauss map of neutral surfaces are studied. Special attention is given to surfaces of parallel, or zero, mean curvature. Bilagrangian structures are defined and used in ways analogous to the use of complex structures in the Riemannian case. The nonsimplicity of the structure group SO(2,2 is used to factor the Gauss map and to construct analogs of the twistor space, called in this context reflector space.

  13. Photodetector with enhanced light absorption

    Science.gov (United States)

    Kane, James

    1985-01-01

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  14. Hail hydrogen

    International Nuclear Information System (INIS)

    Hairston, D.

    1996-01-01

    After years of being scorned and maligned, hydrogen is finding favor in environmental and process applications. There is enormous demand for the industrial gas from petroleum refiners, who need in creasing amounts of hydrogen to remove sulfur and other contaminants from crude oil. In pulp and paper mills, hydrogen is turning up as hydrogen peroxide, displacing bleaching agents based on chlorine. Now, new technologies for making hydrogen have the industry abuzz. With better capabilities of being generated onsite at higher purity levels, recycled and reused, hydrogen is being prepped for a range of applications, from waste reduction to purification of Nylon 6 and hydrogenation of specialty chemicals. The paper discusses the strong market demand for hydrogen, easier routes being developed for hydrogen production, and the use of hydrogen in the future

  15. Achieving Airport Carbon Neutrality

    Science.gov (United States)

    2016-03-01

    This report is a guide for airports that wish to reduce or eliminate greenhouse gas (GHG) emissions from existing buildings and operations. Reaching carbon neutrality typically requires the use of multiple mechanisms to first minimize energy consumpt...

  16. Measurements of the Absorptive Properties of the Ionosphere

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Absorption of radio waves occurs when electrons responding to the wave fields collide with and transfer energy to the neutral particles. A study of ionospheric...

  17. Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen

    DEFF Research Database (Denmark)

    Andersen, Jonas; Voute, A.; Mihrin, Dmytro

    2017-01-01

    conformations of Cs and C2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs....... The combination of concentration dependency measurements, observed isotopic spectral shifts associated with H/D substitutions and dedicated annealing procedures, enables the unambiguous assignment of three large-amplitude infrared active hydrogen bond vibrational modes for the non-planar Cs configuration of (CH2O...

  18. First detection of hydrogen in the β Pictoris gas disk

    Science.gov (United States)

    Wilson, P. A.; Lecavelier des Etangs, A.; Vidal-Madjar, A.; Bourrier, V.; Hébrard, G.; Kiefer, F.; Beust, H.; Ferlet, R.; Lagrange, A.-M.

    2017-03-01

    The young and nearby star β Pictoris (β Pic) is surrounded by a debris disk composed of dust and gas known to host a myriad evaporating exocomets, planetesimals and at least one planet. At an edge-on inclination, as seen from Earth, this system is ideal for debris disk studies providing an excellent opportunity to use absorption spectroscopy to study the planet forming environment. Using the Cosmic Origins Spectrograph (COS) instrument on the Hubble Space Telescope (HST) we observe the most abundant element in the disk, hydrogen, through the H I Lyman α (Ly-α) line. We present a new technique to decrease the contamination of the Ly-α line by geocoronal airglow in COS spectra. This Airglow Virtual Motion (AVM) technique allows us to shift the Ly-α line of the astrophysical target away from the contaminating airglow emission revealing more of the astrophysical line profile. This new AVM technique, together with subtraction of an airglow emission map, allows us to analyse the shape of the β Pic Ly-α emission line profile and from it, calculate the column density of neutral hydrogen surrounding β Pic. The column density of hydrogen in the β Pic stable gas disk at the stellar radial velocity is measured to be log (NH/ 1 cm2) ≪ 18.5. The Ly-α emission line profile is found to be asymmetric and we propose that this is caused by H I falling in towards the star with a bulk radial velocity of 41 ± 6 km s-1 relative to β Pic and a column density of log (NH/ 1 cm2) = 18.6 ± 0.1. The high column density of hydrogen relative to the hydrogen content of CI chondrite meteorites indicates that the bulk of the hydrogen gas does not come from the dust in the disk. This column density reveals a hydrogen abundance much lower than solar, which excludes the possibility that the detected hydrogen could be a remnant of the protoplanetary disk or gas expelled by the star. We hypothesise that the hydrogen gas observed falling towards the star arises from the dissociation of

  19. Solubility and diffusion of hydrogen in pure metals and alloys

    International Nuclear Information System (INIS)

    Wipf, H.

    2001-01-01

    Basic facts are presented of the absorption of hydrogen gas by metals and the diffusion of hydrogen in metals. Specifically considered are crystalline metals without defects and lattice disorder (pure metals), low hydrogen concentrations and the possibility of high hydrogen gas pressures. The first introductory topic is a short presentation of typical phase diagrams of metal hydrogen systems. Then, hydrogen absorption is discussed and shown to be decisively determined by the enthalpy of solution, in particular by its sign which specifies whether absorption is exothermic or endothermic. The formation of high-pressure hydrogen gas bubbles in a metal, which can lead to blistering, is addressed. It is demonstrated that bubble formation will, under realistic conditions, only occur in strongly endothermically hydrogen absorbing metals. The chief aspects of hydrogen diffusion in metals are discussed, especially the large size of the diffusion coefficient and its dependence on lattice structure. It is shown that forces can act on hydrogen in metals, causing a directed hydrogen flux. Such forces arise, for instance, in the presence of stress and temperature gradients and can result in local hydrogen accumulation with potential material failure effects. The final aspect discussed is hydrogen permeation, where the absorption behavior of the hydrogen is found to be in general more decisive on the permeation rate than the value of the diffusion coefficient. (orig.)

  20. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    Science.gov (United States)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  1. Light Absorption Coefficients for Soluble Species in Snow, Dome C, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains light absorption coefficients for soluble chromophores (light-absorbing chemicals) and concentrations of hydrogen peroxide (HOOH) and nitrate...

  2. Hydrogen highway

    International Nuclear Information System (INIS)

    Anon

    2008-01-01

    The USA Administration would like to consider the US power generating industry as a basis ensuring both the full-scale production of hydrogen and the widespread use of the hydrogen related technological processes into the economy [ru

  3. Versatile Hydrogen

    Indian Academy of Sciences (India)

    H m . Some of these compounds have fascinating structures (1,2,3). However the most interesting interaction of hydrogen, is the hydrogen bond. When a hydrogen atom is bound to an electronegative element it acquires a slight positive charge. As a result, it is attracted to other atoms such as nitrogen or oxygen in the ...

  4. Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  5. SECONDARY POPULATION OF INTERSTELLAR NEUTRALS seems deflected to the side

    Science.gov (United States)

    Nakagawa, H.; Bzowski, M.; Yamazaki, A.; Fukunishi, H.; Watanabe, S.; Takahashi, Y.; Taguchi, M.

    Recently the neutral hydrogen flow in the inner heliosphere was found to be deflected relative to the helium flow by about 4 degrees Lallement et al 2005 The explanation of this delfection offered was a distortion of the heliosphere under the action of an ambient interstellar magnetic field In a separate study a number of data sets pertaining to interstellar neutral atoms obtained with various techniques were compiled and interpreted as due to an inflow of interstellar gas from an ecliptic longitude shifted by 10 - 40 degrees from the canonical upstream interstellar neutral flow direction at 254 degrees Collier et al 2004 The origin and properties of such a flow is still under debate We have performed a cross-experiment analysis of the heliospheric hydrogen and helium photometric observations performed simltaneously by the Nozomi spacecraft between the Earth and Mars orbit and explored possible deflection of hydrogen and helium flows with respect to the canonical upwind direction For the interpretation we used predictions of a state of the art 3D and fully time-dependent model of the neutral gas in the heliosphere with the boundary conditions ionization rates and radiation pressure taken from literature The model includes two populations of the thermal interstellar hydrogen predicted by the highly-reputed Moscow Monte Carlo model of the heliosphere The agreement between the data and simulations is not satifactory when one assumes that the upwind direction is the same for both populations and identical with the direction derived from inerstellar helium

  6. Hydrogen in magnesium palladium thin layer structures

    NARCIS (Netherlands)

    Kruijtzer, G.L.

    2008-01-01

    In this thesis, the study of hydrogen storage, absorption and desorption in magnesium layers is described. The magnesium layers have a thickness of 50-500 nm and are covered by a palladium layer which acts as a hydrogen dissociation/association catalyst. The study was preformed under ultra high

  7. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  8. Issues in neutral currents

    International Nuclear Information System (INIS)

    Sehgal, L.M.

    1980-01-01

    The experimental results on low energy confirming the structure of the effective Lagrangian of the weak neutral current processes as predicted by the Salam-Weinberg model are reviewed. Some possible modifications of the effective Lagrangian and the feasibility of their experimental verification are also considered. (P.L.)

  9. Targets for a Neutral Kaon Beam

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Christopher [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-04-01

    A secondary beam of neutral Kaons is under consideration for Hall D at Jefferson Lab to perform spectroscopic studies of hyperons produced by K 0 L particles scattering from proton and deuteron targets. The proposed physics program would utilize the GlueX detector package currently installed in Hall D. This contribution looks at potential targets for use in the new facility, paying close attention to the existing infrastructure of GlueX and Hall D. Unpolarized cryotargets of liquid hydrogen and deuerium, as well as polarized solid targets of protons and deuterons are examined.

  10. Possibilities of hydrogen removal

    International Nuclear Information System (INIS)

    Langer, G.; Koehling, A.; Nikodem, H.

    1982-12-01

    In the event of hypothetical severe accidents in light-water reactors, considerable amounts of hydrogen may be produced and released into the containment. Combustion of the hydrogen may jeopardize the integrity of the containment. The study reported here aimed to identify methods to mitigate the hydrogen problem. These methods should either prevent hydrogen combustion, or limit its effects. The following methods have been investigated: pre-inerting; chemical oxygen absorption; removal of oxygen by combustion; post-inerting with N 2 , CO 2 , or halon; aqueous foam; water fog; deliberate ignition; containment purging; and containment venting. The present state of the art in both nuclear and non-nuclear facilities, has been identified. The assessment of the methods was based on accident scenarios assuming significant release of hydrogen and the spectrum of requirements derived from these scenarios was used to determine the advantages and drawbacks of the various methods, assuming their application in a pressurized-water reactor of German design. (orig.) [de

  11. Divertor, thermonuclear device and method of neutralizing high temperature plasma

    International Nuclear Information System (INIS)

    Ikegami, Hideo.

    1995-01-01

    The thermonuclear device comprises a thermonuclear reactor for taking place fusion reactions to emit fusion plasmas, and a divertor made of a hydrogen occluding material, and the divertor is disposed at a position being in contact with the fusion plasmas after nuclear fusion reaction. The divertor is heated by fusion plasmas after nuclear fusion reaction, and hydrogen is released from the hydrogen occluding material as a constituent material. A gas blanket is formed by the released hydrogen to cool and neutralize the supplied high temperature nuclear fusion plasmas. This prevents the high temperature plasmas from hitting against the divertor, elimination of the divertor by melting and evaporation, and solve a problem of processing a divertor activated by neutrons. In addition, it is possible to utilize hydrogen isotopes of fuels effectively and remove unnecessary helium. Inflow of impurities from out of the system can also be prevented. (N.H.)

  12. Hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Pahwa, P.K.; Pahwa, Gulshan Kumar

    2013-10-01

    In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen has been proposed as the perfect fuel for this future energy system. The availability of a reliable and cost-effective supply, safe and efficient storage, and convenient end use of hydrogen will be essential for a transition to a hydrogen economy. Research is being conducted throughout the world for the development of safe, cost-effective hydrogen production, storage, and end-use technologies that support and foster this transition. This book discusses hydrogen economy vis-a-vis sustainable development. It examines the link between development and energy, prospects of sustainable development, significance of hydrogen energy economy, and provides an authoritative and up-to-date scientific account of hydrogen generation, storage, transportation, and safety.

  13. Generation of intense polarized beams by selective neutralization of negative ions

    International Nuclear Information System (INIS)

    Hershcovitch, A.I.; Hinds, E.A.

    1983-01-01

    A novel scheme is proposed. This method is based on selective neutralization by laser negative hydrogen ions in a magnetic field. This selectivity is based on the fact that the final state of the neutralized atom depends on nuclear polarization in the magnetic field. A two-scenario approach is to be followed: one in which the resulting neutral atom is in the ground state, and in the other the neutral atom is in the n = 2 level. Limiting factors are discussed. The main advantages of this scheme are the availability of multi-ampere negative ion sources and the possibility to neutralize negative ions with very high efficiency. 15 references, 2 figures

  14. Hydrogen peroxide on the surface of Europa

    Science.gov (United States)

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  15. Biomimetic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Krassen, Henning

    2009-05-15

    Hydrogenases catalyze the reduction of protons to molecular hydrogen with outstanding efficiency. An electrode surface which is covered with active hydrogenase molecules becomes a promising alternative to platinum for electrochemical hydrogen production. To immobilize the hydrogenase on the electrode, the gold surface was modified by heterobifunctional molecules. A thiol headgroup on one side allowed the binding to the gold surface and the formation of a self-assembled monolayer. The other side of the molecules provided a surface with a high affinity for the hydrogenase CrHydA1 from Chlamydomonas reinhardtii. With methylviologen as a soluble energy carrier, electrons were transferred from carboxy-terminated electrodes to CrHydA1 and conducted to the active site (H-cluster), where they reduce protons to molecular hydrogen. A combined approach of surface-enhanced infrared absorption spectroscopy, gas chromatography, and surface plasmon resonance allowed quantifying the hydrogen production on a molecular level. Hydrogen was produced with a rate of 85 mol H{sub 2} min{sup -1} mol{sup -1}. On a 1'- benzyl-4,4'-bipyridinum (BBP)-terminated surface, the electrons were mediated by the monolayer and no soluble electron carrier was necessary to achieve a comparable hydrogen production rate (approximately 50% of the former system). The hydrogen evolution potential was determined to be -335 mV for the BBP-bound hydrogenase and -290 mV for the hydrogenase which was immobilized on a carboxy-terminated mercaptopropionic acid SAM. Therefore, both systems significantly reduce the hydrogen production overpotential and allow electrochemical hydrogen production at an energy level which is close to the commercially applied platinum electrodes (hydrogen evolution potential of -270 mV). In order to couple hydrogen production and photosynthesis, photosystem I (PS1) from Synechocystis PCC 6803 and membrane-bound hydrogenase (MBH) from Ralstonia eutropha were bound to each other

  16. Engineering design and manufacturing of prototype neutral injector for JET

    Energy Technology Data Exchange (ETDEWEB)

    De Vere, A.P.C.; Scholes, R.E.; Altmann, H.; Bottiglioni, F.

    1981-01-01

    The first of Neutral Injection heating on JET requires injection of 5 MW of 80 neutral atoms into the plasma torus for times in excess of 10 sec. Eight injectors, each rated at 80 kV and 60 amp of hydrogen ions, will be required to provide this nett 5 MW of full energy hydrogen atoms. This paper describes the engineering design and manufacturing aspects of the prototype versions of these injectors, which are currently referred to as Plug-In Neutral Injectors. In particular the philosophy of accurate alignment of the tetrode accelerator structure on a high voltage insulated flange will be discussed in conjunction with the problem of active cooling of grids.

  17. Engineering design and manufacturing of prototype neutral injector for JET

    International Nuclear Information System (INIS)

    De Vere, A.P.C.; Scholes, R.E.; Altmann, H.; Bottiglioni, F.

    1981-01-01

    The first of Neutral Injection heating on JET requires injection of 5 MW of 80 neutral atoms into the plasma torus for times in excess of 10 sec. Eight injectors, each rated at 80 kV and 60 amp of hydrogen ions, will be required to provide this nett 5 MW of full energy hydrogen atoms. This paper describes the engineering design and manufacturing aspects of the prototype versions of these injectors, which are currently referred to as Plug-In Neutral Injectors. In particular the philosophy of accurate alignment of the tetrode accelerator structure on a high voltage insulated flange will be discussed in conjunction with the problem of active cooling of grids

  18. The absorption effect of the Lα-line Supplement to the paper 'On the Correlation Between the Hα-line emission rate and the ablation rate of a hydrogen pellet in tokamak discharges' – Nuclear Fusion 24 (1984) 697

    DEFF Research Database (Denmark)

    Chang, C. T.; Thomsen, Kenneth

    1985-01-01

    Several assumptions made in a previous study of the correlation between the Hα-line emission rate and the ablation rate of a hydrogen pellet injected into a tokamak discharge showed that the emission layer of the ablatant as optically thin with respect to all levels of the principal quantum numbe...

  19. Hydrogen safety

    International Nuclear Information System (INIS)

    Frazier, W.R.

    1991-01-01

    The NASA experience with hydrogen began in the 1950s when the National Advisory Committee on Aeronautics (NACA) research on rocket fuels was inherited by the newly formed National Aeronautics and Space Administration (NASA). Initial emphasis on the use of hydrogen as a fuel for high-altitude probes, satellites, and aircraft limited the available data on hydrogen hazards to small quantities of hydrogen. NASA began to use hydrogen as the principal liquid propellant for launch vehicles and quickly determined the need for hydrogen safety documentation to support design and operational requirements. The resulting NASA approach to hydrogen safety requires a joint effort by design and safety engineering to address hydrogen hazards and develop procedures for safe operation of equipment and facilities. NASA also determined the need for rigorous training and certification programs for personnel involved with hydrogen use. NASA's current use of hydrogen is mainly for large heavy-lift vehicle propulsion, which necessitates storage of large quantities for fueling space shots and for testing. Future use will involve new applications such as thermal imaging

  20. The influence of blobs on neutral particles in the scrape-off layer

    DEFF Research Database (Denmark)

    Thrysøe, Alexander Simon; Tophøj, Laust Emil Hjerrild; Naulin, Volker

    2016-01-01

    and edge are investigated. Simulations suggest that neutrals originating from dissociation of hydrogen molecules only fuel in the outermost edge region of the plasma, whereas hot neutrals from charge exchange collisions penetrate deep into the bulk plasma. The results are recovered in a simplified 2D model....

  1. Hydrogen Storage and Production Project

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, Abhijit [Univ. of Arkansas, Little Rock, AR (United States); Biris, A. S. [Univ. of Arkansas, Little Rock, AR (United States); Mazumder, M. K. [Univ. of Arkansas, Little Rock, AR (United States); Karabacak, T. [Univ. of Arkansas, Little Rock, AR (United States); Kannarpady, Ganesh [Univ. of Arkansas, Little Rock, AR (United States); Sharma, R. [Univ. of Arkansas, Little Rock, AR (United States)

    2011-07-31

    This is the final technical report. This report is a summary of the project. The goal of our project is to improve solar-to-hydrogen generation efficiency of the PhotoElectroChemical (PEC) conversion process by developing photoanodes with high absorption efficiency in the visible region of the solar radiation spectrum and to increase photo-corrosion resistance of the electrode for generating hydrogen from water. To meet this goal, we synthesized nanostructured heterogeneous semiconducting photoanodes with a higher light absorption efficiency compared to that of TiO2 and used a corrosion protective layer of TiO2. While the advantages of photoelectrochemical (PEC) production of hydrogen have not yet been realized, the recent developments show emergence of new nanostructural designs of photoanodes and choices of materials with significant gains in photoconversion efficiency.

  2. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  3. Ion-Ion Neutralization.

    Science.gov (United States)

    1982-05-31

    of Birmingam, P 0 Box 363, 2310/A2 Birmingham B15 2TT, England. 2303/GlAC II. Controlling Office Name and Address 12. Report Date Air Force Geophysics...source. Thus unwanted molecular excitation and dissociation can be avoided and greater control can be exercised in the creation of suitable plasma...The Fall fractigRal ionization density in these afterglow plagas (%-10 -𔃺) ensures that electron- neutral collisions are the most effective. This

  4. Exercise Equipment: Neutral Buoyancy

    Science.gov (United States)

    Shackelford, Linda; Valle, Paul

    2016-01-01

    Load Bearing Equipment for Neutral Buoyancy (LBE-NB) is an exercise frame that holds two exercising subjects in position as they apply counter forces to each other for lower extremity and spine loading resistance exercises. Resistance exercise prevents bone loss on ISS, but the ISS equipment is too massive for use in exploration craft. Integrating the human into the load directing, load generating, and motion control functions of the exercise equipment generates safe exercise loads with less equipment mass and volume.

  5. Gargamelle: neutral current event

    CERN Multimedia

    1973-01-01

    This event shows real tracks of particles from the 1200 litre Gargamelle bubble chamber that ran on the PS from 1970 to 1976 and on the SPS from 1976 to 1979. In this image a neutrino passes close to a nucleon and reemerges as a neutrino. Such events are called neutral curent, as they are mediated by the Z0 boson which has no electric charge.

  6. Antihypertensive neutral lipid

    Science.gov (United States)

    Snyder, F.L.; Blank, M.L.

    1984-10-26

    The invention relates to the discovery of a class of neutral acetylated either-linked glycerolipids having the capacity to lower blood presure in warm-blooded animals. This physiological effect is structure sensitive requiring a long chain alkyl group at the sn-1 position and a short carbon chain acyl group (acetyl or propionyl) at the sn-2 position, and a hydroxyl group at the sn-3 position.

  7. Why hydrogen

    International Nuclear Information System (INIS)

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  8. Hydrogen millennium

    International Nuclear Information System (INIS)

    Bose, T.K.; Benard, P.

    2000-05-01

    The 10th Canadian Hydrogen Conference was held at the Hilton Hotel in Quebec City from May 28 to May 31, 2000. The topics discussed included current drivers for the hydrogen economy, the international response to these drivers, new initiatives, sustainable as well as biological and hydrocarbon-derived production of hydrogen, defense applications of fuel cells, hydrogen storage on metal hydrides and carbon nanostructures, stationary power and remote application, micro-fuel cells and portable applications, marketing aspects, fuel cell modeling, materials, safety, fuel cell vehicles and residential applications. (author)

  9. Hydrogenation of chalcones using hydrogen permeating through a Pd and palladized Pd electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, M., E-mail: mcgutier@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Nazareno, M.A. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Sosa, V. [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Agencia postal 4, Casilla 61, 5000, Cordoba (Argentina); Lopez de Mishima, B.A., E-mail: bmishima@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Mishima, H.T. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina)

    2010-08-01

    The hydrogenation of benzalacetone and benzalacetophenone was carried out using atomic hydrogen permeating through a palladium membrane. A two-compartment cell separated by a Pd sheet or a palladized Pd (Pd/Pd black) sheet electrode was employed. The reduction products were identified by (GC) gas chromatography, UV-vis absorption spectroscopy and NMR spectroscopy. The carbon-carbon double bond was hydrogenated and the benzylacetone and benzylacetophenone were obtained as products using palladium catalyst. The current efficiency for hydrogenation reaction increases when the current density for water electrolysis decreases and depends on the initial chalcone concentration. It is over 90% at the concentration of 10 mmol L{sup -1}. The hydrogen absorption and diffusion into and through a palladium membrane electrode has been studied by using an electrochemical impedance spectroscopy method. The impedance results would indicate that the hydrogen permeated through the membrane is consumed by the chalcone during the hydrogenation process keeping as the permeable boundary condition in the outer side of the Pd membrane the hydrogen activity almost zero. The hydrogen entering the metal through an adsorbed state and the rate of hydrogen absorption is diffusion-controlled.

  10. Neutral particle beam intensity controller

    Science.gov (United States)

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  11. Hydrogen Storage in Carbon Nanotubes

    Science.gov (United States)

    Gilbert, Joseph; Gilbert, Matthew; Naab, Fabian; Savage, Lauren; Holland, Wayne; Duggan, Jerome; McDaniel, Floyd

    2004-10-01

    Hydrogen as a fuel source is an attractive, relatively clean alternative to fossil fuels. However, a major limitation in its use for the application of automobiles has been the requirement for an efficient hydrogen storage medium. Current hydrogen storage systems are: physical storage in high pressure tanks, metal hydride, and gas-on-solid absorption. However, these methods do not fulfill the Department of Energy's targeted requirements for a usable hydrogen storage capacity of 6.5 wt.%, operation near ambient temperature and pressure, quick extraction and refueling, reliability and reusability.Reports showing high capacity hydrogen storage in single-walled carbon nanotubes originally prompted great excitement in the field, but further research has shown conflicting results. Results for carbon nanostructures have ranged from less than 1 wt.% to 70 wt.%. The wide range of adsorption found in previous experiments results from the difficulty in measuring hydrogen in objects just nanometers in size. Most previous experiments relied on weight analysis and residual gas analysis to determine the amount of hydrogen being adsorbed by the CNTs. These differing results encouraged us to perform our own analysis on single-walled (SWNTs), double-walled (DWNTs), and multi-walled carbon nanotubes (MWNTs), as well as carbon fiber. We chose to utilize direct measurement of hydrogen in the materials using elastic recoil detection analysis (ERDA). This work was supported by the National Science Foundation's Research Experience for Undergraduates and the University of North Texas.

  12. Pretreatment of bituminous coal for hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Hupfer, H.

    1943-03-29

    Bituminous coal became plastic at certain temperature ranges and swelled, causing plugging of preheater tubes. With few exceptions, this problem was encountered only when hydrogenating bituminous coal. This swelling often appeared in the coking of coals, and for the majority of the cases it was found that efforts to reduce the baking ability of bituminous coal also reduced the swelling of coal paste in the preheater tubes. Three methods of pretreatment to reduce swelling were preheating, oxidation (anoxidation), and sulfur treatment. The preheating by hot nitrogen at 250 atm for 3 hours showed no improvement in swelling characteristics, but produced a greater asphalt content and a lower amount of gasification. Absorption of oxygen was shown to increase the viscosity of the coal paste, while preheating in a vacuum showed no effects. Oxidation (anoxidation) increased the splitting and gasification and gave higher asphalt content. The baking ability of Saar coal could be destroyed by addition of 2.5% sulfur and heating for 1/sup 1///sub 2/ hours at 110/sup 0/C, in a stream of H/sub 2/S. The volatile content dropped significantly when the same coal was heated to 200/sup 0/ to 250/sup 0/C. When neutralized Saar coal was dried under a stream of H/sub 2/S, only slight deterioration of the yield was noted with equal degree of gasification. It was concluded that a more or less distinct improvement would be observed from the absorption of sulfur, but that residue processing would have to be altered to account for the sulfur content.

  13. Neutral particle diagnostics for ohmically and auxiliary heated tokamaks

    International Nuclear Information System (INIS)

    Wagner, F.

    1982-01-01

    Protons and hydrogen atoms in a plasma undergo charge-exchange collisions which give rise to an energetic charge-exchange flux emerging from the plasma. The intensity and energy distribution of the charge-exchange flux is measured separately for hydrogen or deuterium. Besides discussing the basic principles and the experimental techniques, this report concentrates on plasma characteristics accessible to neutral particle diagnostics. From the energy distribution of the charge exchange flux, the ion energy distribution can be inferred. In the case of a thermal plasma the measurement of the ion temperature profile allows the analysis of the ion energy transport, and with auxiliary heating the ion heating efficiency can be estimated. From the absolute intensity of the charge-exchange flux the hydrogen atom density can be determined; strong toroidal variation, with sharp increases at limiter and gas input valve, is observed. The atom flux which leaves the plasma hits the wall and forms one branch of plasma wall interaction which can be investigated by measuring the backscattering of neutrals from the wall and by analyzing the wall sputtering due to charge-exchange atoms. Neutral particle diagnostics carried out in the divertor chamber of a divertor tokamak reveal strong plasma wall interaction at the neutralizer plate

  14. Hydrogen Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  15. Adsorption of hydrogen in titanium

    International Nuclear Information System (INIS)

    Martinez R, T.

    1995-01-01

    In this work the absorption of hydrogen in titanium plates using a constant volume system has been realized. The changes of temperature and pressure were used to monitor the progress of the absorption. A stainless steel vacuum chamber with volume of 4,333 cm 3 was used. A titanium sample of 45 x 5.4 x 0.3 cm was located in the center of the chamber. The sample was heated by an electrical source connected to the system. The sample was preconditioned with a vacuum-thermal treatment at 10 -6 mbar and 800 Centigrade degrees for several days. Absorption was observed at room temperature and also at higher temperatures. The room temperature absorption was in the pressure range of 1.0 x 10 3 to 2.5 x 10 3 mbar, and other absorptions were from 180 to 630 Centigrade degrees at 3.5 x 10 -1 to 1.3 x 10 3 mbar. It was found that the gas absorbed was function of the vacuum-thermal pre-conditioned treatment, pressure and temperature. When the first absorption was developed, additional absorptions were realized in short time. We measured the electrical resistivity of the sample in the experiments but we could not see important changes due to the absorption. (Author)

  16. Ultracold neutral plasmas

    Science.gov (United States)

    Lyon, M.; Rolston, S. L.

    2017-01-01

    By photoionizing samples of laser-cooled atoms with laser light tuned just above the ionization limit, plasmas can be created with electron and ion temperatures below 10 K. These ultracold neutral plasmas have extended the temperature bounds of plasma physics by two orders of magnitude. Table-top experiments, using many of the tools from atomic physics, allow for the study of plasma phenomena in this new regime with independent control over the density and temperature of the plasma through the excitation process. Characteristic of these systems is an inhomogeneous density profile, inherited from the density distribution of the laser-cooled neutral atom sample. Most work has dealt with unconfined plasmas in vacuum, which expand outward at velocities of order 100 m/s, governed by electron pressure, and with lifetimes of order 100 μs, limited by stray electric fields. Using detection of charged particles and optical detection techniques, a wide variety of properties and phenomena have been observed, including expansion dynamics, collective excitations in both the electrons and ions, and collisional properties. Through three-body recombination collisions, the plasmas rapidly form Rydberg atoms, and clouds of cold Rydberg atoms have been observed to spontaneously avalanche ionize to form plasmas. Of particular interest is the possibility of the formation of strongly coupled plasmas, where Coulomb forces dominate thermal motion and correlations become important. The strongest impediment to strong coupling is disorder-induced heating, a process in which Coulomb energy from an initially disordered sample is converted into thermal energy. This restricts electrons to a weakly coupled regime and leaves the ions barely within the strongly coupled regime. This review will give an overview of the field of ultracold neutral plasmas, from its inception in 1999 to current work, including efforts to increase strong coupling and effects on plasma properties due to strong coupling.

  17. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  18. Hydrogen energy.

    Science.gov (United States)

    Edwards, P P; Kuznetsov, V L; David, W I F

    2007-04-15

    The problem of anthropogenically driven climate change and its inextricable link to our global society's present and future energy needs are arguably the greatest challenge facing our planet. Hydrogen is now widely regarded as one key element of a potential energy solution for the twenty-first century, capable of assisting in issues of environmental emissions, sustainability and energy security. Hydrogen has the potential to provide for energy in transportation, distributed heat and power generation and energy storage systems with little or no impact on the environment, both locally and globally. However, any transition from a carbon-based (fossil fuel) energy system to a hydrogen-based economy involves significant scientific, technological and socio-economic barriers. This brief report aims to outline the basis of the growing worldwide interest in hydrogen energy and examines some of the important issues relating to the future development of hydrogen as an energy vector.

  19. Ablation of Solid Hydrogen in a Plasma

    DEFF Research Database (Denmark)

    Jørgensen, L. W.; Sillesen, Alfred Hegaard

    1979-01-01

    Several hydrogen pellet ablation models based on the formation of a shielding neutral cloud have been reported by different authors. The predicted ablation rates are shown to follow almost the same scaling law and this is used to explain the authors' ablation experiment.......Several hydrogen pellet ablation models based on the formation of a shielding neutral cloud have been reported by different authors. The predicted ablation rates are shown to follow almost the same scaling law and this is used to explain the authors' ablation experiment....

  20. Spectral interferences in atomic absorption spectrometry, (5)

    International Nuclear Information System (INIS)

    Daidoji, Hidehiro

    1979-01-01

    Spectral interferences were observed in trace element analysis of concentrated solutions by atomic absorption spectrometry. Molecular absorption and emission spectra for strontium chloride and nitrate, barium chloride and nitrate containing 12 mg/ml of metal ion in airacetylene flame were measured in the wavelength range from 200 to 700 nm. The absorption and emission spectra of SrO were centered near 364.6 nm. The absorption spectra of SrOH around 606.0, 671.0 and 682.0 nm were very strong. And, emission spectrum of BaOH in the wavelength range from 480 to 550 nm was stronger. But, the absorption of this band spectrum was very weak. In the wavelength range from 200 to 400 nm, some unknown bands of absorption were observed for strontium and barium. Absorption spectra of SrCl and BaCl were observed in the argon-hydrogen flame. Also, in the carbon tube atomizer, the absorption spectra of SrCl and BaCl were detected clearly in the wavelength range from 185 to 400 nm. (author)

  1. Neutral Beam Injection for Plasma and Magnetic Field Diagnostics

    International Nuclear Information System (INIS)

    Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Kwan, Joe W.; Levinton, Fred

    2007-01-01

    At the Lawrence Berkeley National Laboratory (LBNL) a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. High proton fraction and small divergence is essential for diagnostic neutral beams. In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller) elliptical beam spot at 2.5 m from the end of the extraction column is produced. The beam will deliver up to 5 A of hydrogen beam to the target with a pulse width of ∼1 s, once every 1-2 min. The H1+ ion species of the hydrogen beam will be over 90 percent. For this application, we have compared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antenna behind a dielectric RF-window. The second one uses an internal antenna in similar ion source geometry. The source needs to generate uniform plasma over a large (8 cm x 5 cm) extraction area. We expect that the ion source with internal antenna will be more efficient at producing the desired plasma density but might have the issue of limited antenna lifetime, depending on the duty factor. For both approaches there is a need for extra shielding to protect the dielectric materials from the backstreaming electrons. The source walls will be made of insulator material such as quartz that has been observed to generate plasma with higher atomic fraction than sources with metal walls. The ion beam will be extracted and accelerated by a set of grids with slits, thus forming an array of 6 sheet-shaped beamlets. The multiple grid extraction will be optimized using computer simulation programs. Neutralization of the beam will be done in neutralization chamber, which has over 70 percent neutralization efficiency

  2. Analysis of particle species evolution in neutral beam injection lines

    International Nuclear Information System (INIS)

    Kim, J.; Haselton, H.H.

    1978-07-01

    Analytic solutions to the rate equations describing the species evolution of a multispecies positive ion beam of hydrogen due to charge exchange and molecular dissociation are derived as a function of the background gas (H 2 ) line density in the neutralizing gas cell and in the drift tube. Using the solutions, calculations are presented for the relative abundance of each species as a function of the gas cell thickness, the reionization loss rates in the drift tube, and the neutral beam power as a function of the beam energy and the species composition of the original ion beam

  3. Hydrogen-related effects in crystalline semiconductors

    International Nuclear Information System (INIS)

    Haller, E.E.

    1988-08-01

    Recent experimental and theoretical information regarding the states of hydrogen in crystalline semiconductors is reviewed. The abundance of results illustrates that hydrogen does not preferentially occupy a few specific lattice sites but that it binds to native defects and impurities, forming a large variety of neutral and electrically active complexes. The study of hydrogen passivated shallow acceptors and donors and of partially passivated multivalent acceptors has yielded information on the electronic and real space structure and on the chemical composition of these complexes. Infrared spectroscopy, ion channeling, hydrogen isotope substitution and electric field drift experiments have shown that both static trigonal complexes as well as centers with tunneling hydrogen exist. Total energy calculations indicate that the charge state of the hydrogen ion which leads to passivation dominates, i.e., H + in p-type and H/sup /minus// in n-type crystals. Recent theoretical calculations indicate that is unlikely for a large fraction of the atomic hydrogen to exist in its neutral state, a result which is consistent with the total absence of any Electron Paramagnetic Resonance (EPR) signal. An alternative explanation for this result is the formation of H 2 . Despite the numerous experimental and theoretical results on hydrogen-related effects in Ge and Si there remains a wealth of interesting physics to be explored, especially in compound and alloy semiconductors. 6 refs., 6 figs

  4. Hydrogen-related effects in crystalline semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Haller, E.E.

    1988-08-01

    Recent experimental and theoretical information regarding the states of hydrogen in crystalline semiconductors is reviewed. The abundance of results illustrates that hydrogen does not preferentially occupy a few specific lattice sites but that it binds to native defects and impurities, forming a large variety of neutral and electrically active complexes. The study of hydrogen passivated shallow acceptors and donors and of partially passivated multivalent acceptors has yielded information on the electronic and real space structure and on the chemical composition of these complexes. Infrared spectroscopy, ion channeling, hydrogen isotope substitution and electric field drift experiments have shown that both static trigonal complexes as well as centers with tunneling hydrogen exist. Total energy calculations indicate that the charge state of the hydrogen ion which leads to passivation dominates, i.e., H/sup +/ in p-type and H/sup /minus// in n-type crystals. Recent theoretical calculations indicate that is unlikely for a large fraction of the atomic hydrogen to exist in its neutral state, a result which is consistent with the total absence of any Electron Paramagnetic Resonance (EPR) signal. An alternative explanation for this result is the formation of H/sub 2/. Despite the numerous experimental and theoretical results on hydrogen-related effects in Ge and Si there remains a wealth of interesting physics to be explored, especially in compound and alloy semiconductors. 6 refs., 6 figs.

  5. Hydrogen neutral outflowing disks of B[e] supergiants

    Czech Academy of Sciences Publication Activity Database

    Kraus, Michaela; Borges Fernandes, M.; de Araújo, F. X.

    2008-01-01

    Roč. 33, - (2008), s. 47-49 ISSN 1405-2059. [Massive Stars: Fundamental Parameters and Circumstellar Interactions. Buenos Aires, 11.12.2006-14.12.2006] R&D Projects: GA AV ČR KJB300030701; GA ČR GA205/04/1267 Institutional research plan: CEZ:AV0Z10030501 Keywords : stars * mass loss * stars winds Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  6. Charge transfer and ionization involving argon ions and neutral hydrogen

    International Nuclear Information System (INIS)

    Errea, L F; Illescas, Clara; Mendez, L; Pons, B; Riera, A; Suarez, J

    2006-01-01

    We present classical trajectory Monte Carlo (CTMC) calculations of total and partial cross sections for capture and ionization in Ar 18+ , Ar 17+ , Ar 16+ +H(1s) collisions in the 30-300 keV amu -1 impact energy range. We specially focus on capture into high-lying states of the projectile, which are of paramount importance for diagnostics of fusion plasmas involving Ar q+ seeding. (letter to the editor)

  7. Neutral hydrogen and optical properties of three amorphous galaxies

    Science.gov (United States)

    Hunter, Deidre A.; Woerden, Hugo Van; Gallagher, John S., III

    1994-01-01

    We present new interferometric H I and optical observations of three amorphous galaxies, systems with a smooth, high surface brightness but an asymmetrical distribution of light. All three galaxies are forming stars and have LMC-like emission-line ratios, low dust content, and high H I velocity dispersions. NGC 1140 has a boxy inner morphology with a hook off one corner. At low light levels unusual extensions of starlight are seen curving to the northwest and southeast. The galaxy contains a very luminous central star-forming region and a small chain of H II regions that coincide with the hook. The central H II region has broad H(alpha) velocity profiles full width at half maximum (FWHM) less than or equal to 140 km/s, and it is a radio continuum source. There is a rotating H I gas disk, 40 kpc in radius, at a position angle 51 deg from the optical major axis. The central gas ridge follows the chain of H II regions, and the H I peak is on the hook. The outer gas on the southeast side curves away from the H I major axis. The central gas density is high, and the surface density declines very slowly with radius. The rotation velocity yields a mass of 1 x 10(exp 11) solar mass at 3.3 Holmberg radii (R(sub H)). NGC 1800 has a hook that coincides with a large H II region, and an r(exp 1/4) luminosity distribution. There are numerous H II regions along the major axis and extraordinary filaments of ionized gas. Emanating from the major axis on either side of the galaxy are H(alpha) fingers approximately 750 pc long. About 2.3 kpc to the north is a web of filaments approximately 3 kpc in extent. H(alpha) profiles of H II regions and filaments are narrow. The H I gas disk has a position angle that is approximately 13 deg different from that of the optical axis. There are two peaks near the center, one of which is near the largest H II region. Beyond the Holmberg radius to the west is a 6 x 10(exp 6) solar mass H I cloud. Its velocity indicates a mass of approximately 6 x 10(exp 9) solar mass for NGC 1800 at 1.5 R(sub H). At approximately R(sub 25) to the east there is a large H I shell. Also at approximately R(sub 25) on both sides the velocity gradient switches by 90 deg, and in the interior the rotation is about the major axis. The central gas density is low and falls off slowly. In the inner regions NGC 4670 resembles an S0/a galaxy seen rather edge-on. It contains a central supergiant H II region with very high velocity widths (FWHM less than or equal to 180 km/s) and complex velocity structures. It is a radio continuum source as well. The H I gas is a single spherical cloud or a disk at low inclination centered on the galaxy with a slight elongation along the optical major axis and rotation about the minor axis. The central gas density is high, and there is a high degree of concentration. The rotation speed indicates a total mass of 5 x 10(exp 10) solar mass at 1.1 R(sub H). We compare these characteristics with properties of gas in the presence of stellar bar potentials, gas warps, and interacting and merging galaxy models. Although there are inconsistencies and uncertainties, we conclude that NGC 1140 is a spiral of low surface brightness that has undergone a merger, while NGC 1800 and NGC 4670 are, respectively, probably an Im system and a spiral that had an encounter of the Noguchi (1988a) kind.

  8. The Evolution of Neutral Hydrogen in Galaxy Groups

    Science.gov (United States)

    Sanderson, Kelly Nicole; Wilcots, Eric; Hess, Kelley M.

    2018-01-01

    The Illustris suite of simulations is held as the standard of large scale gravitational and hydro-dynamical simulations and allows us to make a better comparisons with physical processes at the gaseous level by providing a higher mass resolution than previously available through the Millenium-II simulation. We present a comparison of an analysis on the HI content and distribution of galaxies in groups as a function of their group dark matter halo to the results of a large scale cosmological simulation. From the simulation we select optical group members above a Mr=-18 r-band magnitude and HI group members with HI above 109.5M⊙. We find that 74% of the HI detected galaxies are in groups or clusters and 84% of the optically detected galaxies are in groups or clusters. In the Hess & Wilcots (2013) paper it was found that as group membership, or group dark matter halo mass, increased, the fraction of galaxies detected in HI decreased and the spatial distribution of galaxies in these groups increased. We show the spatial distributions of galaxies, HI and optically detected, in order to reproduce these results. We find that Illustris qualitatively reproduces these trends, however, the simulation seems to be overestimating the mass of HI gas in all of its galaxies as well as the number of galaxies above the 109.5M⊙ limit.

  9. Hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Donath, E.

    1942-10-16

    This report mentioned that not very severe demands for purity were made on the hydrogen used in hydrogenation of coal or similar raw materials, because the catalysts were not very sensitive to poisoning. However, the hydrogenation plants tried to remove most impurities anyway by means of oil washes. The report included a table giving the amount of wash oil used up and the amount of hydrogen lost by dissolving into the wash oil used up and the amount of hydrogen lost by dissolving into the wash oil in order to remove 1% of various impurities from 1000 m/sup 3/ of the circulating gas. The amounts of wash oil used up were 1.1 m/sup 3/ for removing 1% nitrogen, 0.3 m/sup 3/ for 1% carbon monoxide, 0.03 m/sup 3/ for 1% methane. The amount of hydrogen lost was 28 m/sup 3/ for 1% nitrogen, 9 m/sup 3/ for 1% methane and ranged from 9 m/sup 3/ to 39 m/sup 3/ for 1% carbon monoxide and 1 m/sup 3/ to 41 m/sup 3/ for carbon dioxide depending on whether the removal was done in liquid phase or vapor phase and with or without reduction of the oxide to methane. Next the report listed and described the major processes used in German hydrogenation plants to produce hydrogen. Most of them produced water gas, which then had its carbon monoxide changed to carbon dioxide, and the carbon oxides washed out with water under pressure and copper hydroxide solution. The methods included the Winkler, Pintsch-Hillebrand, and Schmalfeldt-Wintershall processes, as well as roasting of coke in a rotating generator, splitting of gases formed during hydrogenation, and separation of cokery gas into its components by the Linde process.

  10. INTERSTELLAR NEUTRAL ATOMS AT 1 AU OBSERVED BY THE IMAGE/LENA IMAGER

    International Nuclear Information System (INIS)

    Fuselier, S. A.; Ghielmetti, A. G.; Wurz, P.

    2009-01-01

    Observations from the Imager for Magnetopause to Aurora: Global Exploration (IMAGE) Low Energy Neutral Atom (LENA) imager from 2005 are used to investigate characteristics of interstellar neutrals in the inner solar system. The LENA imager detected an interstellar neutral signal starting in 2004 December and extending to early 2005 April. Using the orientation of the field of view of the imager and the date of the loss of the interstellar neutral signal, it is concluded that the signal is consistent with a relatively compact (several degrees wide in ecliptic latitude and longitude) source of neutral helium and/or energetic (>150 eV) hydrogen originating from the solar apex direction. Observations later in 2005 are used to distinguish the composition and conclude that the relatively compact source likely contains some energetic hydrogen (in addition to the helium).

  11. High-pressure hydrogen materials compatibility of piezoelectric films

    Science.gov (United States)

    Alvine, K. J.; Shutthanandan, V.; Bennett, W. D.; Bonham, C. C.; Skorski, D.; Pitman, S. G.; Dahl, M. E.; Henager, C. H.

    2010-11-01

    Hydrogen is well known for materials compatibility issues, including blistering and embrittlement in metals, which are challenges for its use as the next-generation "green" fuel. Beyond metals, hydrogen also degrades piezoelectric materials used as actuators used in direct injection hydrogen internal combustion engines. We present the materials compatibility studies of piezoelectric films in high-pressure hydrogen environments. Absorption of high-pressure hydrogen and composition changes were studied with an elastic recoil detection analysis and Rutherford back-scattering spectrometry in lead zirconate titanate and barium titanate thin films. Hydrogen surface degradation in the form of blistering and Pb mixing was also observed.

  12. Cooperativity Enables Non-neutralizing Antibodies to Neutralize Ebolavirus

    Directory of Open Access Journals (Sweden)

    Katie A. Howell

    2017-04-01

    Full Text Available Drug combinations are synergistic when their combined efficacy exceeds the sum of the individual actions, but they rarely include ineffective drugs that become effective only in combination. We identified several “enabling pairs” of neutralizing and non-neutralizing anti-ebolavirus monoclonal antibodies, whose combination exhibited new functional profiles, including transforming a non-neutralizing antibody to a neutralizer. Sub-neutralizing concentrations of antibodies 2G4 or m8C4 enabled non-neutralizing antibody FVM09 (IC50 >1 μM to exhibit potent neutralization (IC50 1–10 nM. While FVM09 or m8C4 alone failed to protect Ebola-virus-infected mice, a combination of the two antibodies provided 100% protection. Furthermore, non-neutralizers FVM09 and FVM02 exponentially enhanced the potency of two neutralizing antibodies against both Ebola and Sudan viruses. We identified a hotspot for the binding of these enabling antibody pairs near the interface of the glycan cap and GP2. Enabling cooperativity may be an underappreciated phenomenon for viruses, with implications for the design and development of immunotherapeutics and vaccines.

  13. Hydrogen absorption in Mg1.95Ti0.05Ni0.95Cu0.05 alloy prepared with mechanical alloying and thermal treatment; Absorcion de hidrogeno en la aleacion Mg1.95Ti0.05Ni0.95Cu0.05 preparada por aleado mecanico y tratamiento termico

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Juan Bonifacio; Urena Nunez, Fernando [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: juan.bonifacio@inin.gob.mx

    2009-09-15

    This work presents hydrogen absorption in quaternary alloy Mg1.95Ti0.05Ni0.95Cu0.05 obtained by the mechanical alloying method, followed by thermal treatment in ultra-high pure argon atmosphere. The composition of the phases, microstructure and morphology of ground powders and with thermal treatment were characterized by DRX, SEM/EDS and TEM. After 20 hours of mechanical grinding and recooked at 300 degrees Celsius/1h in argon atmosphere, the quaternary alloy has a Mg{sub 2}Ni crystalline hexagonal structure with a crystallite size under 10 nm. The absorption measurements were performed under a pressure of 0.2 to 1.2 MPa at a temperature of 200 degrees Celsius in a micro-reactor. The quantification of absorption-desorption of hydrogen in the intermetallic was conducted in a TGA-DSC simultaneous calorimeter. Metallic hydride-dehydride powder was characterized with SEM and XRD. [Spanish] En este trabajo se presenta la absorcion de hidrogeno en la aleacion cuaternaria Mg1.95Ti0.05Ni0.95Cu0.05 obtenida por el metodo de aleado mecanico, seguida de tratamiento termico en atmosfera de argon de ultra alta pureza. La composicion de las fases, microestructura y morfologia de los polvos molidos y con tratamiento termico fue caracterizada por DRX, SEM/EDS y TEM. Despues de 20 h de molienda mecanica con recocido a 300 grados Celsios/1h en atmosfera de argon, la aleacion cuaternaria tiene una estructura cristalina hexagonal Mg{sub 2}Ni con tamano de cristalito menor a 10 nm. Las mediciones de absorcion fueron realizadas bajo una presion de 0.2 a 1.2 MPa a una temperatura de 200 grados Celsios en un micro-reactor. La cuantificacion de absorcion-desorcion de hidrogeno en el intermetalico se realizo en un calorimetro simultaneo TGA-DSC. Se determino que la cantidad maxima absorbida de hidrogeno en la aleacion cuaternaria fue de 3.24% en peso cuando la presion fue de 0.8 MPa a dicha temperatura. Polvos metalicos hidrurados-deshidrurados se caracterizaron por SEM y XRD.

  14. Mod en neutral seksualitet!

    DEFF Research Database (Denmark)

    Leer, Jonatan

    2013-01-01

    Towards a Neutral Sexuality! or Roland Barthes as a Queer Thinker? This article argues that the work of Roland Barthes has interesting perspectives in common with the queer theory. This argument will be put forward by using his concept of ‘the neutral’ that Barthes defines as “that which outplays...... the paradigm”. This notion was presented at a series of lectures at Collège de France in 1977. Through a reading of Barthes’s autobiography, Roland Barthes par Roland Barthes (1975), the article demonstrates how Barthes in this text tries to outplay the paradigms that rules over the hegemonic understanding...... theory” in the late 1970’s that beside Barthes includes Jean Baudrillard....

  15. Neutral Kaon Spectrometer 2

    Science.gov (United States)

    Kaneta, M.; Beckford, B.; Fujii, T.; Fujii, Y.; Futatsukawa, K.; Han, Y. C.; Hashimoto, O.; Hirose, K.; Ishikawa, T.; Kanda, H.; Kimura, C.; Maeda, K.; Nakamura, S. N.; Suzuki, K.; Tsukada, K.; Yamamoto, F.; Yamazaki, H.

    2018-04-01

    A large-acceptance spectrometer, Neutral Kaon Spectrometer 2 (NKS2), was newly constructed to explore various photoproduction reactions in the gigaelectronvolt region at the Laboratory of Nuclear Science (LNS, currently ELPH), Tohoku University. The spectrometer consisted of a dipole magnet, drift chambers, and plastic scintillation counters. NKS2 was designed to separate pions and protons in a momentum range of less than 1 GeV/ c, and was placed in a tagged photon beamline. A cryogenic H2/D2 target fitted to the spectrometer were designed. The design and performance of the detectors are described. The results of the NKS2 experiment on analyzing strangeness photoproduction data using a 0.8-1.1 GeV tagged photon beam are also presented.

  16. Spectroscopy of neutral radium

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Aran; De, Subhadeep; Jungmann, Klaus; Wilschut, Hans; Willmann, Lorenz [KVI, University of Groningen, Groningen (Netherlands)

    2008-07-01

    The heavy alkaline earth atoms radium is uniquely sensitive towards parity and time reversal symmetry violations due to a large enhancement of an intrinsic permanent electric dipole moment of the nucleous or the electron. Furthermore, radium is sensitive to atomic parity violation and the nuclear anapole moment. To prepare such experiments spectroscopy of relevant atomic states need to be done. At a later stage we will build a neutral atom trap for radium. We have built an atomic beam of the short lived isotope {sup 225}Ra with a flux of several 10{sup 4} atoms/sec. We are preparing the laser spectroscopy using this beam setup. In the preparation for efficient laser cooling and trapping we have successfully trapped barium, which is similar in it's requirements for laser cooling. The techniques which we have developed with barium can be used to trap rare radium isotopes. We report on the progress of the experiments.

  17. Plasma diagnosis by dye laser intracavity absorption: Final report for period January 1, 1982-May 31, 1986

    International Nuclear Information System (INIS)

    Brink, G.O.

    1986-05-01

    Dye laser intracavity absorption (ICA) has been studied as a potential diagnostic for plasma or neutral beam systems. For magnetic field measurements it is necessary to make Zeeman effect measurements on the resonance transition of atomic lithium on a millisecond time scale, or to make motional Stark Effect measurements on an injected fast atomic beam of hydrogen. To do this it may be necessary to sweep the dye laser in wavelength at a rapid rate so that the absorber can be sampled many times during the measurement. We have examined both of these possibilities during this contract. A rather detailed absorption spectrum of molecular hydrogen and deuterium arising in the 2c 3 Piu and other electronic states has been obtained and analyzed. This has provided new information on the types of molecular species that may be detected in a plasma by ICA, and may provide a basis for the application of ICA for the diagnosis of the edge plasma in a tokamak or in the end regions of a mirror machine

  18. LADEE Neutral Mass Spectrometer Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This bundle contains the data collected by the Neutral Mass Spectrometer (NMS) instrument aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE)...

  19. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint)

    Science.gov (United States)

    2007-01-18

    report on fundamental experiments to understand how much electron current can be drawn to a surrogate anode from the plume of low power arcjets ...operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster- arcjet neutralizer package. In the...concept demonstration. The arcjet operated at very low powers (~ 70-120W) on helium, at a mass flow rate of 4.5 mg/s, and was able to effectively

  20. Design considerations for large cryopumps for high power neutral injectors

    International Nuclear Information System (INIS)

    Coupland, J.R.; Hammond, D.P.; Thompson, E.

    1976-01-01

    The megawatt neutral injector being designed at Culham Laboratory will require pumps capable of handling pulsed hydrogen gas loads of more than 20 litre Torr sec -1 . Pressures of -4 Torr need to be maintained in the presence of this gas load implying installed pumping speeds > 2 x 10 5 litres sec -1 . Some fundamental concepts pertaining to cryopumps operating at relatively high pressures and some of the design parameters which need to be taken into consideration, are examined

  1. Ethanol reformation combined with CO{sub 2} absorption for the production of hydrogen; Reformacion de etanol combinada con absorcion de CO{sub 2} para produccion de hidrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Beltran-Pina, B.B.; Delgado-Vigil, M.D.; Salinas-Gutierrez, J.M.; Lopez-Ortiz, A.; Collins-Martinez, V. [Centro de Investigacion en Materiales Avanzados S. C, Chihuahua, Chihuahua (Mexico)]. E-mail: bogdan.beltran@cimav.edu.mx

    2009-09-15

    This work studied the ethanol reforming reaction combined with carbonatation of a metallic oxide to produce hydrogen with CO{sub 2} capture in one single step. A catalyst mixture was used composed of 10 %wt Ni/Al{sub 2}O{sub 3} with a CO{sub 2} absorbent material such as calcined dolomite (CaO*MgO) and sodium zirconate (Na{sub 2}ZrO{sub 3}). The materials synthesized were characterized with x-ray diffraction (XRD), sweep electron microscopy (SEM) and surface area (BET isotherma). A catalyst with a very dispersed active phase and surface area of 170 m{sup 2}/gr was obtained. The evaluation of the ethanol steam reforming reaction was conducted considering a transient system and a stainless steel fixed-bed reactor where catalyst mixtures and CO{sub 2} absorbents were introduced. The reaction was carried out at a temperature of 600 degrees Celsius, with a water/alcohol ratio of 6:1. The quantification of the gases produced during the reaction (H{sub 2}, CO{sub 2}, CO and CH{sub 4}) was performed with gas chromatography. An increase was observed in the hydrogen selectivity when adding absorbent to the catalytic bed from 85% to 98% with dolomite and 97% with sodium zirconate. In addition, a considerable decrease was observed in the selectivity to by-products such as CH{sub 4} and CO{sub 2}. The amount of carbon deposited on the surface of the materials was determined. This increase in the production of hydrogen is attributable to a shift in the thermal dynamic equilibrium of the reforming reaction, according to the Chatelier's principle. [Spanish] Se ha estudiado la reaccion de reformacion de etanol combinada con la carbonatacion de un oxido metalico para la produccion de hidrogeno con captura de CO{sub 2} en un solo paso. Se utilizo una mezcla de un catalizador compuesto de 10 %wt Ni/Al{sub 2}O{sub 3} con un material absorbente de CO{sub 2}, tal como: CaO*MgO (dolomita calcinada) y Na{sub 2}ZrO{sub 3} (zirconato de sodio). Los materiales sintetizados fueron

  2. Inclusive Photoproduction of Neutral k* Mesons

    Science.gov (United States)

    Kolya, Scott Daniel

    Available from UMI in association with The British Library. Requires signed TDF. This thesis presents results from the 1985 data taking of the WA69 experiment at the OMEGA spectrometer, CERN, Geneva, performed by the EGAMMA collaboration (Bonn, CERN, Lancaster, Manchester, RAL, Sheffield, Yerevan). A tagged photon beam of energy 70-170 GeV, produced through bremsstrahlung of an electron beam, was incident on a liquid hydrogen target. The OMEGA spectrometer, together with various downstream detectors, were triggered to record the resulting hadronic interactions. In this thesis the experimental apparatus and software are described, with particular emphasis on the Ring Image Cerenkov detector (RICH). Preliminary analysis of the inclusive production of neutral K*(890) mesons is presented. The RICH is used to identify kaons in the Kpi final state. The Feynman-X (X_ {F}) distributions are compared to the predictions of the quark fusion and LUND fragmentation models of low P_{t} production.

  3. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  4. Nutrition and magnesium absorption

    OpenAIRE

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium absorption was neither affected by soybean protein in the diet nor by supplemental phytate. The inhibitory influence of soybean protein and phytate on apparent magnesium absorption was found ...

  5. Electromagnetic radiation optimum neutralizer

    International Nuclear Information System (INIS)

    Smirnov, Igor

    2002-01-01

    This particular article relates to subtle electrical effects, and provides some evidence of a fundamental nature on how subtle low frequency electromagnetic fields might be utilized to protect human body against harmful effects of high frequencies electromagnetic radiation. I have focused my efforts on definite polar polymer compound named EMRON which is patented in the USA. This polar polymer compound can be excited by external high frequencies electromagnetic fields to generate subtle low frequency oscillations that are beneficial for cellular life structures. This concept is based on the possibility of existence of resonance phenomenon between polar polymers and biopolymers such as proteins, nucleic acids, lipids, etc. Low frequency patterns generated by defined polar polymer compound can interact with biostructures and transmit the signals that support and improve cellular functions in the body. The mechanism of this process was confirmed by number of studies. The animal (including human) brain is affected by electromagnetic waves to the extent that production of Alpha or Theta waves can be directly induced into brain by carrying an ELF (extremely low frequency, 5-12 Hz) signal on a microwave carrier frequency. EMRON does not reduce the power of electromagnetic fields. It 'shields' the cellular structures of the body against the harmful effects of EMR. The radiation is still entering the body but the neutralizing effect of EMRON renders the radiation harmless

  6. Simulation of the time dependent infrared nu2 mode absorptions of (oH2)n:H2O clusters in O2 doped solid hydrogen at 4.2 K.

    Science.gov (United States)

    Abouaf-Marguin, L; Vasserot, A-M; Pardanaud, C

    2009-02-07

    Using Fourier transform infrared spectroscopy, we have analyzed the time evolution of the nu(2) mode of (oH(2))(n):H(2)O clusters (n = 11 to 1) embedded in solid normal hydrogen at 4.2 K over a period of 150 h using paramagnetic O(2) to speed up the ortho to para nuclear spin conversion process. For concentrations H(2)O/O(2)/H(2) = 1/20/4000, at time t = 0 right after the solid is prepared, all the H(2)O molecules are preferentially clustered by large numbers of oH(2). With time the cluster distribution irreversibly shifts toward smaller cluster sizes and also generates freely rotating H(2)O (n = 0) which is solvated completely by pH(2) molecules. From a spectral decomposition of the nu(2) (oH(2))(n):H(2)O cluster spectra, a phenomenological simulation of the time behavior of the clusters has been developed. The time evolution is modeled using coupled rate equations in a step by step n to n-1 cluster cascade fashion and analyzed over nine successive time periods. It shows that rotating H(2)O grows only at the expense of cluster n = 1 and that the process dramatically slows down as the conversion of orthohydrogen proceeds. At the end of the conversion process, it was found that cluster n = 1 remained with a very slow decrease.

  7. Absorption and excretion tests

    International Nuclear Information System (INIS)

    Berberich, R.

    1988-01-01

    The absorption and excretion of radiopharmaceuticals is still of interest in diagnostic investigations of nuclear medicine. In this paper the most common methods of measuring absorption and excretion are described. The performance of the different tests and their standard values are discussed. More over the basic possibilities of measuring absorption and excretion including the needed measurement equipments are presented. (orig.) [de

  8. Hydrogen program overview

    Energy Technology Data Exchange (ETDEWEB)

    Gronich, S. [Dept. of Energy, Washington, DC (United States). Office of Utility Technologies

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  9. The low energy neutral fluxes and their impurity production at the walls of ASDEX

    International Nuclear Information System (INIS)

    Verbeek, H.; Dose, V.; Fu, J.K.; Gehre, O.; Gernhardt, J.; Janeschitz, G.; Mueller, E.R.; Roehr, H.; Steuer, K.H.; Soeldner, F.X.

    1988-01-01

    With the Low Energy Neutral particle Analyser LENA at ASDEX the density dependence of the neutral flux, its mean energy and its impurity production at the walls has been investigated for ohmic hydrogen and deuterium discharges. For hydrogen a large increase of the neutral flux with increasing density was observed, while the mean energy of the neutrals decreases. This holds for hydrogen over the whole range of densities. At constant density the low energy neutral flux increases with the safety factor q. This is in contrast to the high energy flux as measured with the charge exchange analyser. The flux increase of the low energy neutrals can be correlated with the increased decay length of the electron density for higher q-values. For deuterium the same behaviour up to densities of n ≅ 3.5x10 13 cm -3 was observed. For higher densities the flux behaves different corresponding to the different confinement regimes. Only in the regime of saturated ohmic confinement, known so far, the flux increases further with increasing n. With the operational conditions of the new divertor configuration in ASDEX a further increase of τ E with n up to the density limit was observed (improved Ohmic confinement). In this regime the neutral flux saturates with increasing n. In spite of the reduced impurity production at the walls, Z eff increases in this case. (orig.)

  10. An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5

    Science.gov (United States)

    Bañados, Eduardo; Venemans, Bram P.; Mazzucchelli, Chiara; Farina, Emanuele P.; Walter, Fabian; Wang, Feige; Decarli, Roberto; Stern, Daniel; Fan, Xiaohui; Davies, Frederick B.; Hennawi, Joseph F.; Simcoe, Robert A.; Turner, Monica L.; Rix, Hans-Walter; Yang, Jinyi; Kelson, Daniel D.; Rudie, Gwen C.; Winters, Jan Martin

    2018-01-01

    Quasars are the most luminous non-transient objects known and as a result they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120 + 0641 at redshift z = 7.09 has remained the only one known at z > 7 for more than half a decade. Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 × 1013 times the luminosity of the Sun and a black-hole mass of 8 × 108 solar masses. The existence of this supermassive black hole when the Universe was only 690 million years old—just five per cent of its current age—reinforces models of early black-hole growth that allow black holes with initial masses of more than about 104 solar masses or episodic hyper-Eddington accretion. We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman α emission line (the Gunn–Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

  11. An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5.

    Science.gov (United States)

    Bañados, Eduardo; Venemans, Bram P; Mazzucchelli, Chiara; Farina, Emanuele P; Walter, Fabian; Wang, Feige; Decarli, Roberto; Stern, Daniel; Fan, Xiaohui; Davies, Frederick B; Hennawi, Joseph F; Simcoe, Robert A; Turner, Monica L; Rix, Hans-Walter; Yang, Jinyi; Kelson, Daniel D; Rudie, Gwen C; Winters, Jan Martin

    2018-01-25

    Quasars are the most luminous non-transient objects known and as a result they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120 + 0641 at redshift z = 7.09 has remained the only one known at z > 7 for more than half a decade. Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 × 10 13 times the luminosity of the Sun and a black-hole mass of 8 × 10 8 solar masses. The existence of this supermassive black hole when the Universe was only 690 million years old-just five per cent of its current age-reinforces models of early black-hole growth that allow black holes with initial masses of more than about 10 4 solar masses or episodic hyper-Eddington accretion. We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman α emission line (the Gunn-Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

  12. Separation of seven arsenic compounds by high performance liquid chromatography with on-line detection by hydrogen-argon flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, S. H.; Larsen, Erik Huusfeldt; Pritzl, G.

    1992-01-01

    the HPLC column to the nebulizer of the atomic absorption spectrometer. Arsenite, arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) were separated from each other and from the co-injected cationic arsenic compounds, arsenobetaine (AsB), arsenocholine (AsC) and the tetramethylarsonium ion (TMAs......) on an organic polymeric anion-exchange column with 0.1 mol dm-3 carbonate at pH 10.3 as the mobile phase. The three cationic species were separated from each other and from the co-injected anionic species on a silica based cation-exchange column with pyridine at a pH of 2.65 as the mobile phase. The signal...... of mixtures of arsenic standards into the HPLC system were: arsenite, As(III) 1.1; arsenate, As(V) 1.4; MMA 1.4; DMA 0.7; AsB 0.3; AsC 0.5; and the TMAs 0.4. The HPLC-AAS system was used for the analysis of arsenic species in aqueous extracts of soil samples from a polluted land site. Only arsenate was found...

  13. Breakthrough characteristics of gas absorption in a packed column

    International Nuclear Information System (INIS)

    Shitanda, Shoji; Fukada, Satoshi; Koto, Kenji; Mitsuishi, Nobuo

    1979-01-01

    In nuclear industries, the operations to collect or recover various radioactive and non-radioactive gases with a number of absorption or adsorption reagents are practically utilized or planned. Specifically in the operations of recovering hydrogen isotopes, the direct collecting method with active metals such as uranium, zirconium (Zr) and yttrium is watched with keen interest. In this study, the capability of recovering hydrogen by means of Zr was investigated through the estimation of rate-determining step, by flowing the gas mixture of hydrogen and argon after activating metallic Zr under the condition of high temperature and high vacuum, and by determining overall mass transfer coefficient from the absorption breakthrough curves. The details of a packed column and the flowsheet are also described, and the deterioration of Zr powder is considered. That is, the diffusion speed and absorbing reaction speed of hydrogen in Zr particles are supposed to be slow and dominant in mass transfer speed. Further, since gas mixture does not simply diffuse in Zr particles, but the reaction plane seems to move toward the center from the surface in the case of Zr, different from general adsorbents, the moving speed seems to give large effect on the rate-determining step. It is ensured that the hydrogen absorption with Zr powder is so active that hydrogen in gas flow can easily be recovered, and its separation from other gases can be effectively carried out by the desorption of hydrogen from Zr powder by heating it in vacuum. (Wakatsuki, Y.)

  14. Spectrophotometric determination of yeast RNA with neutral red ...

    African Journals Online (AJOL)

    The interaction of neutral red (NR) with yeast RNA (yRNA) was studied by UV-Vis spectrophotometry to develop a simple spectrophotometric method for the determination yRNA. NR exhibited a maximum absorption peak at 528 nm in a Britton-Robinson (B-R) buffer solution of pH 4.0. After the addition of yRNA into NR ...

  15. Innovative Monitoring of Atmospheric Gaseous Hydrogen Fluoride

    OpenAIRE

    Dugheri, Stefano; Bonari, Alessandro; Pompilio, Ilenia; Monti, Alessandro; Mucci, Nicola; Arcangeli, Giulio

    2016-01-01

    Hydrogen fluoride (HF) is a basic raw material for a wide variety of industrial products, with a worldwide production capacity of more than three million metric tonnes. A novel method for determining particulate fluoride and gaseous hydrogen fluoride in air is presented herewith. Air was sampled using miniaturised 13?mm Swinnex two-stage filter holders in a medium-flow pumping system and through the absorption of particulate fluoride and HF vapours on cellulose ester filters uncoated or impre...

  16. Hydrogen usage

    Energy Technology Data Exchange (ETDEWEB)

    1942-10-22

    This short tabular report listed the number of m/sup 3/ of hydrogen required for a (metric) ton of product for various combinations of raw material and product in a hydrogenation procedure. In producing auto gasoline, bituminous coal required 2800 m/sup 3/, brown coal required 2400 m/sup 3/, high-temperature-carbonization tar required 2100 m/sup 3/, bituminous coal distillation tar required 1300 m/sup 3/, brown-coal low-temperature-carbonization tar required 850 m/sup 3/, petroleum residues required 900 m/sup 3/, and gas oil required 500 m/sup 3/. In producing diesel oil, brown coal required 1900 m/sup 3/, whereas petroleum residues required 500 m/sup 3/. In producing diesel oil, lubricants, and paraffin by the TTH (low-temperature-hydrogenation) process, brown-coal low-temperature-carbonization tar required 550 m/sup 3/. 1 table.

  17. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  18. Hydrogen: the future energy carrier.

    Science.gov (United States)

    Züttel, Andreas; Remhof, Arndt; Borgschulte, Andreas; Friedrichs, Oliver

    2010-07-28

    Since the beginning of the twenty-first century the limitations of the fossil age with regard to the continuing growth of energy demand, the peaking mining rate of oil, the growing impact of CO2 emissions on the environment and the dependency of the economy in the industrialized world on the availability of fossil fuels became very obvious. A major change in the energy economy from fossil energy carriers to renewable energy fluxes is necessary. The main challenge is to efficiently convert renewable energy into electricity and the storage of electricity or the production of a synthetic fuel. Hydrogen is produced from water by electricity through an electrolyser. The storage of hydrogen in its molecular or atomic form is a materials challenge. Some hydrides are known to exhibit a hydrogen density comparable to oil; however, these hydrides require a sophisticated storage system. The system energy density is significantly smaller than the energy density of fossil fuels. An interesting alternative to the direct storage of hydrogen are synthetic hydrocarbons produced from hydrogen and CO2 extracted from the atmosphere. They are CO2 neutral and stored like fossil fuels. Conventional combustion engines and turbines can be used in order to convert the stored energy into work and heat.

  19. Infrared absorption of 1-chloro-2-methyl-2-propyl [⋅C(CH3)2CH2Cl] and 2-chloro-2-methylpropyl [⋅CH2C(CH3)2Cl] radicals produced in the addition reactions of Cl with isobutene (i-C4H8) in solid para-hydrogen.

    Science.gov (United States)

    Chou, Ching-Yin; Lee, Yuan-Pern

    2016-10-07

    The addition reactions of chlorine atom with isobutene (i-C 4 H 8 ) in solid para-hydrogen (p-H 2 ) were investigated with infrared (IR) absorption spectra. When a p-H 2 matrix containing Cl 2 and isobutene was irradiated with ultraviolet light at 365 nm, intense lines in a set at 534.5, 1001.0, 1212.9, 1366.0, 2961.6, and 2934.7 cm -1 , and several weaker others due to the 1-chloro-2-methyl-2-propyl radical, ⋅ C(CH 3 ) 2 CH 2 Cl, and those in a second set including intense ones at 642.7, 799.2, 1098.2, 1371.8, and 3027.3 cm -1 due to the 2-chloro-2-methylpropyl radical, ⋅ CH 2 C(CH 3 ) 2 Cl, appeared; the ratio of ⋅ C(CH 3 ) 2 CH 2 Cl to ⋅ CH 2 C(CH 3 ) 2 Cl was approximately (3 ± 1):1. The observed wavenumbers and relative intensities agree with the vibrational wavenumbers and IR intensities predicted with the B3PW91/aug-cc-pVTZ method. That the Cl atom adds to both carbons of the C=C bond of isobutene with the terminal site slightly favored is consistent with the energies of products predicted theoretically, but is in contrast to the reaction of Cl + propene in solid p-H 2 in which the addition of Cl to mainly the central C atom was previously reported. The role of the p-H 2 matrix in affecting the reaction paths is discussed. Absorption lines of the complex i-C 4 H 8 ⋅Cl 2 and the dichloro-product anti-1,2-dichloro-2-methylpropane, a-CH 2 ClCCl(CH 3 ) 2 , are also characterized.

  20. Corrosion inhibitor for aqueous ammonia absorption system

    Science.gov (United States)

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  1. Versatile Hydrogen

    Indian Academy of Sciences (India)

    Hydrogen is probably the most intriguing ele- ment in the periodic table. Although it is only the seventh most abundant element on earth, it is the most abundant element in the uni- verse. It combines with almost all the ele- ments of the periodic table, except for a few transition elements, to form binary compounds of the type E.

  2. Metastable hydrogen

    International Nuclear Information System (INIS)

    Dose, V.

    1982-01-01

    This paper deals with the basic physical properties of the metastable 2 2 sub(1/2) state of atomic hydrogen. Applications relying on its special properties, including measurement of the Lamb shift, production of spin-polarized protons and the measurement of molecular electric moments, are discussed. (author)

  3. Absorption capacity of fructose in healthy adults. Comparison with sucrose and its constituent monosaccharides

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1986-01-01

    state the absorption capacity of fructose given alone ranges from less than 5 g to more than 50 g. The absorption capacity of fructose given as sucrose is much higher. Glucose stimulates fructose uptake in a dose dependent fashion. The possible existence of more than one intestinal transport system......The capacity to absorb fructose in 10 healthy adults was investigated by means of hydrogen breath analysis. Fructose absorption was quantified with lactulose standards. Significant hydrogen production (greater than or equal to 20 ppm rise of breath hydrogen) was found after challenge with 10...

  4. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  5. Analytic treatment of distributions of lithium neutrals and ions in linear devices

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyu-Sun, E-mail: kschung@hanyang.ac.kr [Department of Electrical Engineering, Hanyang University, Seoul (Korea, Republic of); Hirooka, Yoshi; Ashikawa, Naoko [National Institute for Fusion Science, Toki (Japan); Cho, Soon Gook; Choi, Heung Gyoon; Kang, In Je [Department of Electrical Engineering, Hanyang University, Seoul (Korea, Republic of); Tsuchiya, Hayato [National Institute for Fusion Science, Toki (Japan)

    2017-06-15

    Neutral lithium (Li) has been used for the mitigation of heat flux to the plasma facing components and for the control of hydrogen of fusion plasmas. Radial and axial variations of densities of Li neutrals and ions are obtained analytically for a cylindrical chamber by assuming the classical diffusion with or without the magnetic field (B). Neutrals and ions without B can be expressed as a linear combination of the modified Bessel functions of order zero (I{sub 0} and K{sub 0}), while ions with B are to be expressed as the square root of them. Analytical solutions of Li neutral densities with Dirichlet and Neumann boundary conditions are compared to those using Monte Carlo simulation and experimental values of the LIGHT-1 (Lithium Injection Gettering of Hydrogen and its Transport experiments) device. Proper combinations of the relaxation length and size of the source would produce well fitted profiles similar to those observed experimentally and those using Monte Carlo codes.

  6. Determination of the neutral to charged current cross-section ratio for antineutrino interactions on protons

    Science.gov (United States)

    Moreels, J.; Van Doninck, W.; Alamatsaz, H.; Armenise, N.; Azemoon, T.; Bartley, J. H.; Baton, J. P.; Belusevic, R.; Bertrand, D.; Brisson, V.; Calicchio, M.; Colley, D. C.; Cooper, A. M.; Erriquez, O.; Fogli-muciaccia, M. T.; Gerbier, G.; Guy, J. G.; Jones, G. T.; Kochowski, C.; Michette, A. G.; Natali, S.; Neveu, M.; Nuzzo, S.; O'Neale, S.; Parker, M. A.; Petiau, P.; Ruggieri, F.; Sacton, J.; Sewell, S.; Tyndel, M.; Vander Velde, G.; Venus, W.; Vortuba, M. F.; BEBC TST Neutrino Collaboration

    1984-04-01

    An exposure of BEBC equipped with the hydrogen-filled TST to the overlinevμ wide band beam at the CERN SPS has been used to study overlinevμ interactions on free protons. About neutral induced interactions have been observed inside the hydrogen and separated into charged current, neutral current and neutral hadron interactions using a multivariate discriminant analysis based on the kinematics of the events. The neutral to charged current cross-section ratio has been determined to be R poverlinev = 0.33 ± 0.04 . When combined with the value of Rpv previously determined in the same experiment, the result is compatible with the prediction of the standard SU (2) × U (1) model for sin 2θW = 0.24 -0.08+0.06 and ρ = 1.07 -0.08+0.06. Fixing the parameter ρ = 1 yields sin 2θW = 0.18 ± 0.04.

  7. LIGHT-WEIGHT NANOCRYSTALLINE HYDROGEN STORAGE MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    S. G. Sankar; B. Zande; R.T. Obermyer; S. Simizu

    2005-11-21

    During Phase I of this SBIR Program, Advanced Materials Corporation has addressed two key issues concerning hydrogen storage: 1. We have conducted preliminary studies on the effect of certain catalysts in modifying the hydrogen absorption characteristics of nanocrystalline magnesium. 2. We have also conducted proof-of-concept design and construction of a prototype instrument that would rapidly screen materials for hydrogen storage employing chemical combinatorial technique in combination with a Pressure-Composition Isotherm Measurement (PCI) instrument. 3. Preliminary results obtained in this study approach are described in this report.

  8. Industrial implications of hydrogen

    International Nuclear Information System (INIS)

    Pressouyre, G.M.

    1982-01-01

    Two major industrial implications of hydrogen are examined: problems related to the effect of hydrogen on materials properties (hydrogen embrittlement), and problems related to the use and production of hydrogen as a future energy vector [fr

  9. Neutral source and particle balance in the HSX edge

    Science.gov (United States)

    Stephey, Laurie; Kumar, Santhosh; Bader, Aaron; Akerson, Adrian; Schmitz, Oliver; Anderson, David; A, Simon; Talmadge, Joseph; Hegna, Chris

    2015-11-01

    The ability to control the neutral particle and impurity source in fusion devices is critical to obtaining high purity, high confinement plasmas. The neutral particle source defines the edge density gradients and plasma flows. To understand the relationship between the neutral particle source, plasma density gradients and plasma edge and core transport in HSX, a single reservoir particle balance is being used to provide a complete particle inventory. Detailed spectroscopic measurements of hydrogen and helium emission have yielded neutral and plasma profiles and ionization length estimations. The plasma puff source rate has been directly measured. To determine the recycling source rate, two specially designed limiters will be inserted to intercept 99% of the field lines, resulting in a well-defined LCFS and plasma interaction zone. Single limiter insertion resulted in a 50% reduction in global line emission, implying a reduction in wall recycling. Future camera and probe measurements will provide a recycling source rate. HSX neutral physics is also being investigated using EMC3-EIRENE. All results are discussed along with complementary plans for the Wendelstein 7-X startup phase. This work supported by US DOE Grant DE-FG02-93ER54222 and DE-SC0006103.

  10. Neutral and plasma shielding model for pellet ablation

    International Nuclear Information System (INIS)

    Houlberg, W.A.; Milora, S.L.; Attenberger, S.E.

    1987-10-01

    The neutral gas shielding model for ablation of frozen hydrogenic pellets is extended to include the effects of an initial Maxwelliam distribution of incident electron energies; a cold plasma shield outside the neutral shield and extended along the magnetic field; energetic neutral beam ions and alpha particles; and self-limiting electron ablation in the collisionless plasma limit. Including the full electron distribution increases ablation, but adding the cold ionized shield reduces ablation; the net effect is a modest reduction in pellet penetration compared with the monoenergetic electron neutral shielding model with no plasma shield. Unlike electrons, fast ions can enter the neutral shield directly without passing through the cold ionized shield because their gyro-orbits are typically larger than the diameter of the cold plasma tube. Fast alpha particles should not enhance the ablation rate unless their population exceeds that expected from local classical thermalization. Fast beam ions, however, may enhance ablation in the plasma periphery if their population is high enough. Self-limiting ablation in the collisionless limit leads to a temporary distortion of the original plasma electron Maxwellian distribution function through preferential depopulation of the higher-energy electrons. 23 refs., 9 figs

  11. Hydrogen storage by physisorption on porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Panella, B.

    2006-09-13

    A great challenge for commercializing hydrogen powered vehicles is on-board hydrogen storage using economic and secure systems. A possible solution is hydrogen storage in light-weight solid materials. Here three principle storage mechanisms can be distinguished: i) absorption of hydrogen in metals ii) formation of compounds with ionic character, like complex hydrides and iii) physisorption (or physical adsorption) of hydrogen molecules on porous materials. Physical adsorption exhibits several advantages over chemical hydrogen storage as for example the complete reversibility and the fast kinetics. Two classes of porous materials were investigated for physical hydrogen storage, i.e. different carbon nanostructures and crystalline metal-organic frameworks possessing extremely high specific surface area. Hydrogen adsorption isotherms were measured using a Sieverts' apparatus both at room temperature and at 77 K at pressures up to the saturation regime. Additionally, the adsorption sites of hydrogen in these porous materials were identified using thermal desorption spectroscopy extended to very low temperatures (down to 20 K). Furthermore, the adsorbed hydrogen phase was studied in various materials using Raman spectroscopy at different pressures and temperatures. The results show that the maximum hydrogen storage capacity of porous materials correlates linearly with the specific surface area and is independent of structure and composition. In addition the pore structure of the adsorbent plays an important role for hydrogen storage since the adsorption sites for H2 could be assigned to pores possessing different dimensions. Accordingly it was shown that small pores are necessary to reach high storage capacities already at low pressures. This new understanding may help to tailor and optimize new porous materials for hydrogen storage. (orig.)

  12. Carbon compound used in hydrogen storage

    International Nuclear Information System (INIS)

    Iturbe G, J.L.; Lopez M, B.E.

    2004-01-01

    In the present work it is studied the activated carbon of mineral origin for the sorption of hydrogen. The carbon decreased of particle size by means of the one alloyed mechanical. The time of mill was of 10 hours. The characterization one carries out by scanning electron microscopy and X-ray diffraction. The hydrogen sipped in the carbon material it was determined using the Thermal gravimetric method (TGA). The conditions of hydrogenation went at 10 atm of pressure and ambient temperature during 18 hours. They were also carried out absorption/desorption cycles of hydrogen in the same one system of thermal gravimetric analysis. The results showed percentages of sorption of 2% approximately in the cycles carried out in the system TGA and of 4.5% in weight of hydrogen at pressure of 10 atmospheres and ambient temperature during 18 hours. (Author)

  13. Absorption heat pumps

    International Nuclear Information System (INIS)

    Formigoni, C.

    1998-01-01

    A brief description of the difference between a compression and an absorption heat pump is made, and the reasons why absorption systems have spread lately are given. Studies and projects recently started in the field of absorption heat pumps, as well as criteria usually followed in project development are described. An outline (performance targets, basic components) of a project on a water/air absorption heat pump, running on natural gas or LPG, is given. The project was developed by the Robur Group as an evolution of a water absorption refrigerator operating with a water/ammonia solution, which has been on the market for a long time and recently innovated. Finally, a list of the main energy and cost advantages deriving from the use of absorption heat pumps is made [it

  14. Neutrality Versus Materiality: A Thermodynamic Theory of Neutral Surfaces

    Directory of Open Access Journals (Sweden)

    Rémi Tailleux

    2016-09-01

    Full Text Available In this paper, a theory for constructing quasi-neutral density variables γ directly in thermodynamic space is formulated, which is based on minimising the absolute value of a purely thermodynamic quantity J n . Physically, J n has a dual dynamic/thermodynamic interpretation as the quantity controlling the energy cost of adiabatic and isohaline parcel exchanges on material surfaces, as well as the dependence of in-situ density on spiciness, in a description of water masses based on γ, spiciness and pressure. Mathematically, minimising | J n | in thermodynamic space is showed to be equivalent to maximising neutrality in physical space. The physics of epineutral dispersion is also reviewed and discussed. It is argued, in particular, that epineutral dispersion is best understood as the aggregate effect of many individual non-neutral stirring events (being understood here as adiabatic and isohaline events with non-zero buoyancy, so that it is only the net displacement aggregated over many events that is approximately neutral. This new view resolves an apparent paradox between the focus in neutral density theory on zero-buoyancy motions and the overwhelming evidence that lateral dispersion in the ocean is primarily caused by non-zero buoyancy processes such as tides, residual currents and sheared internal waves. The efficiency by which a physical process contributes to lateral dispersion can be characterised by its energy signature, with those processes releasing available potential energy (negative energy cost being more efficient than purely neutral processes with zero energy cost. The latter mechanism occurs in the wedge of instability, and its source of energy is the coupling between baroclinicity, thermobaricity, and density compensated temperature/salinity anomalies. Such a mechanism, which can only exist in a salty ocean, is speculated to be important for dissipating spiciness anomalies and neutral helicity. The paper also discusses potential

  15. Distribution of forbidden neutral carbon emission in the ring nebula (NGC 6720)

    Science.gov (United States)

    Jewitt, D. C.; Danielson, G. E.; Kupferman, P. N.; Maran, S. P.

    1983-01-01

    The spatial distribution of forbidden C I 9823, 9850 A emission in NGC 6720 is reported. Like forbidden O I, the forbidden C I radiation appears enhanced in the region of the bright filaments. A few percent of the carbon atoms in the filaments are neutral. The neutral fraction is consistent with ionization equilibrium calculations made under the assumption of complete shielding of direct stellar radiation by hydrogen. The observed carbon lines are excited by photoelectrons produced from hydrogen by the nebular diffuse radiation field. The forbidden C I observations confirm that the filaments in NGC 6720 are regions of locally enhanced shielding.

  16. Weak neutral-current interactions

    International Nuclear Information System (INIS)

    Barnett, R.M.

    1978-08-01

    The roles of each type of experiment in establishing uniquely the values of the the neutral-current couplings of u and d quarks are analyzed together with their implications for gauge models of the weak and electromagnetic interactions. An analysis of the neutral-current couplings of electrons and of the data based on the assumption that only one Z 0 boson exists is given. Also a model-independent analysis of parity violation experiments is discussed. 85 references

  17. Weak neutral-current interactions

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, R.M.

    1978-08-01

    The roles of each type of experiment in establishing uniquely the values of the the neutral-current couplings of u and d quarks are analyzed together with their implications for gauge models of the weak and electromagnetic interactions. An analysis of the neutral-current couplings of electrons and of the data based on the assumption that only one Z/sup 0/ boson exists is given. Also a model-independent analysis of parity violation experiments is discussed. 85 references. (JFP)

  18. Resonant Self-Trapping and Absorption of Intense Bessel Beams

    International Nuclear Information System (INIS)

    Fan, J.; Parra, E.; Milchberg, H. M.

    2000-01-01

    We report the observation of resonant self-trapping and enhanced laser-plasma heating resulting from propagation of high intensity Bessel beams in neutral gas. The enhancement in absorption and plasma heating is directly correlated to the spatial trapping of laser radiation. (c) 2000 The American Physical Society

  19. Observation of the charge neutrality of the ions from target short-pulse laser interaction experiments

    International Nuclear Information System (INIS)

    Yasuike, Kazuhito

    2003-01-01

    Intended to simulate the early stage of the plasma (preformed plasma) formation in the higher (10 20 W cm -2 ) intensity experiments (in which the plasma density profile rules laser absorption thus conversion efficiency from laser into hot electrons, ions and x-rays) experiments using solid target were done under a peak intensity (main laser pulse) of up to ∼10 15 W cm -2 and pre-pulse and pedestal intensity of ∼10 3 times lower than main pulse. With pedestal, significant enhancement of laser absorption was observed with pedestal condition. Charge neutralization of the ions from the plasma was measured by biased charge collectors. Earlier part of the ion were almost un-neutralized in with or without pedestal condition, and the later part of the ions (≤ few keV) were partially neutralized (≥40%). These not-perfect charge neutralization results is different from the longer nano-seconds pulse experimental results. (author)

  20. Vendor neutral archive in PACS.

    Science.gov (United States)

    Agarwal, Tapesh Kumar; Sanjeev

    2012-10-01

    An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. "Vendor neutral" may not be a suitable term, and "architecture neutral," "PACS neutral," "content neutral," or "third-party neutral" are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe.

  1. Vendor neutral archive in PACS

    Directory of Open Access Journals (Sweden)

    Tapesh Kumar Agarwal

    2012-01-01

    Full Text Available An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. "Vendor neutral" may not be a suitable term, and "architecture neutral," "PACS neutral," "content neutral," or "third-party neutral" are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe.

  2. Site Specificity in Femtosecond Laser Desorption of Neutral H Atoms from Graphite(0001)

    DEFF Research Database (Denmark)

    Frigge, R.; Hoger, T.; Siemer, B.

    2010-01-01

    Femtosecond laser excitation and density functional theory reveal site and vibrational state specificity in neutral atomic hydrogen desorption from graphite induced by multiple electronic transitions. Multimodal velocity distributions witness the participation of ortho and para pair states...... of chemisorbed hydrogen in the desorption process. Very slow velocities of 700 and 400  ms-1 for H and D atoms are associated with the desorption out of the highest vibrational state of a barrierless potential....

  3. STUDIES ON SOLVENT EXTRACTION OF FREE HYDROGEN ...

    African Journals Online (AJOL)

    chromatography with visible absorption spectrometry and obtained a detection limit of 0.01 mg/Cu [10]. ... Seto et al.,. [12] applied colorimetry, ion-specific electrode and headspace gas chromatography with a .... Previous studies have shown that toxicity of cyanides to aquatic organisms is by free hydrogen cyanide and not ...

  4. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    weak (strained) Si–Si bond thereby apparently enhancing the hydrogen diffusion and increasing the light-induced dangling bonds. Keywords. Hydrogenated amorphous silicon; metastable electronic states; hydrogen diffusion. PACS Nos 61.43.Dq; 66.30.-h; 71.23.Cq. 1. Introduction. Hydrogen passivation of dangling bonds ...

  5. Neutral gas and impurity ion flow produced by a plasma sound wave

    International Nuclear Information System (INIS)

    Ohkawa, T.; Miller, R.L.

    1993-01-01

    It is proposed to launch an ion sound wave near the divertor plate of a tokamak plasma to direct the flow of impurities and neutrals in the divertor region. By exciting the ion sound wave with a properly phased second harmonic component, nonlinear effects in the collisional drag of neutrals and impurities can be exploited to yield a time-averaged flow of both hydrogen gas and impurities towards the divertor plate. Thus impurities can be restrained from entering the plasma interior, and an increased neutral density in the divertor region can reduce recycling and enhance radiative cooling there. (Author)

  6. Study of neutral currents in the Argonne 12-foot bubble chamber

    International Nuclear Information System (INIS)

    Hyman, L.G.

    1975-01-01

    Using the ANL 12-foot H 2 bubble chamber filled with hydrogen and deuterium, neutral current events were isolated in the channels νp → νpπ 0 , νp → νnπ + , νn → νpπ - and νn → ν K 0 /sub s/Λ 0 . The neutral current sample is compared to the corresponding charged current interactions. The background reactions which contribute to these channels were carefully studied, and it was concluded that we could isolate the neutral current signal. The Weinberg--Salam gauge model is in good agreement with the data. (U.S.)

  7. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  8. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  9. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  10. Theoretical models of mercury dissolution from dental amalgams in neutral and acidic flows

    Science.gov (United States)

    Keanini, Russell G.; Ferracane, Jack L.; Okabe, Toru

    2001-06-01

    This article reports an experimental and theoretical investigation of mercury dissolution from dental amalgams immersed in neutral (noncorrosive) and acidic (corrosive) flows. Atomic absorption spectrophotometric measurements of Hg loss indicate that in neutral flow, surface oxide films formed in air prior to immersion persist and effectively suppress significant mercury release. In acidic (pH 1) flows, by contrast, oxide films are unstable and dissolve; depending on the amalgam’s material composition, particularly its copper content, two distinct mercury release mechanisms are initiated. In low copper amalgam, high initial mercury release rates are observed and appear to reflect preferential mercury dissolution from unstable Sn8Hg ( γ 2) grains within the amalgam matrix. In high copper amalgam, mercury release rates are initially low, but increase with time. Microscopic examination suggests that this feature reflects corrosion of copper from grains of Cu6Sn5 ( η') and consequent exposure of Ag2Hg3 ( γ 1) grains; the latter serve as internal mercury release sites and become more numerous as corrosion proceeds. Three theoretical models are proposed in order to explain observed dissolution characteristics. Model I, applicable to high and low copper amalgams in neutral flow, assumes that mercury dissolution is mediated by solid diffusion within the amalgam, and that a thin oxide film persists on the amalgam’s surface and lumps diffusive in-film transport into an effective convective boundary condition. Model II, applicable to low copper amalgam in acidic flow, assumes that the amalgam’s external oxide film dissolves on a short time scale relative to the experimental observation period; it neglects corrosive suppression of mercury transport. Model III, applicable to high copper amalgam in acidic flow, assumes that internal mercury release sites are created by corrosion of copper in η' grains and that corrosion proceeds via an oxidation-reduction reaction

  11. Hydrogen local vibrational modes in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, Matthew D. [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-06-01

    Following, a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient. exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen. the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the [111] direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, and anti-crossing is observed between LVM and phonon modes.

  12. Hydrogen local vibrational modes in semiconductors

    Science.gov (United States)

    McCluskey, Matthew Douglas

    Following a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient, exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen, the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the (111) direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, an anti-crossing is observed between the LVM and phonon modes.

  13. 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.)

  14. Development and calibration of the fast neutral particle analyzer of the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Siri, B.

    1989-10-01

    The design and construction of an analyzer for the Tore Supra tokamak fast neutral particles are presented. The energy analysis of the hydrogen and deuterium fast neutrals from the plasma allows the obtention of the plasma ionic temperature. The principle of the analysis is described. The analysis maximal energy is 300 keV for the protons and 150 keV for the deuterons. The measurement of the flow of neutrals in a given energy gap requires the knowledge of the energy of analysis, energy resolution and efficiency of the analyzer. The determination of these parameters needed the utilization of a neutral particle beam of 0 to 50 KeV energy. The energy spectra of the neutrals and the plasma ionic temperature at Tore Supra were obtained [fr

  15. Electromagnetic trapping of neutral atoms

    International Nuclear Information System (INIS)

    Metcalf, H.J.

    1986-01-01

    Cooling and trapping of neutral atoms is a new branch of applied physics that has potential for application in many areas. The authors present an introduction to laser cooling and magnetic trapping. Some basic ideas and fundamental limitations are discussed, and the first successful experiments are reviewed. Trapping a neutral object depends on the interaction between an inhomogeneous electromagnetic field and a multiple moment that results in the exchange of kinetic for potential energy. In neutral atom traps, the potential energy must be stored as internal atomic energy, resulting in two immediate and extremely important consequences. First, the atomic energy levels will necessarily shift as the atoms move in the trap, and, second, practical traps for ground state neutral atoms atr necessarily very shallow compared to thermal energy. This small depth also dictates stringent vacuum requirements because a trapped atom cannot survive a single collision with a thermal energy background gas molecule. Neutral trapping, therefore, depends on substantial cooling of a thermal atomic sample and is inextricably connected with the cooling process

  16. Solubility of hydrogen in transition metals

    International Nuclear Information System (INIS)

    Lee, H.M.

    1976-01-01

    Correlations exist between the heat of solution of hydrogen and the difference in energy between the lowest lying energy levels of the trivalent d/sup n-1/s electronic configuration and the divalent d/sup n-2/s 2 (or the tetravalent d/sup n/) configuration of the neutral gaseous atoms. The trends observed in the transition metal series are discussed in relation to the number of valence electrons per atom in the transition elements in their metallic and neutral states

  17. A new fundamental hydrogen defect in alkali halides

    International Nuclear Information System (INIS)

    Morato, S.P.; Luety, F.

    1978-01-01

    Atom hydrogen in neutral (H 0 ) and negative (H - ) form on substitutional and interstitial lattice sites gives rise to well characterized model defects in alkali-halides (U,U 1 ,U 2 ,U 3 centers), which have been extensively investigated in the past. When studying the photo-decomposition of OH - defects, a new configuration of atomic charged hidrogen was discovered, which can be produced in large quantities in the crystal and is apparently not connected to any other impurity. This new hidrogen defect does not show any pronounced electronic absorption, but displays a single sharp local mode band (at 1114cm -1 in KCl) with a perfect isotope shift. The defect can be produced by various UV or X-ray techniques in crystais doped with OH - , Sh - or H - defects. A detailed study of its formation kinetics at low temperature shows that it is primarily formed by the reaction of a mobile CI 2 - crowdion (H-center) with hidrogen defects [pt

  18. High and rapid hydrogen release from thermolysis of ammonia borane near PEM fuel cell operating temperature

    Science.gov (United States)

    Varma, Arvind; Hwang, Hyun Tae; Al-Kukhun, Ahmad

    2016-11-15

    A system for generating and purifying hydrogen. To generate hydrogen, the system includes inlets configured to receive a hydrogen carrier and an inert insulator, a mixing chamber configured to combine the hydrogen carrier and the inert insulator, a heat exchanger configured to apply heat to the mixture of hydrogen carrier and the inert insulator, wherein the applied heat results in the generation of hydrogen from the hydrogen carrier, and an outlet configured to release the generated hydrogen. To purify hydrogen, the system includes a primary inlet to receive a starting material and an ammonia filtration subassembly, which may include an absorption column configured to absorb the ammonia into water for providing purified hydrogen at a first purity level. The ammonia filtration subassembly may also include an adsorbent member configured to adsorb ammonia from the starting material into an adsorbent for providing purified hydrogen at a second purity level.

  19. Neutral B meson flavor tagging

    CERN Document Server

    Wilson, R J

    2001-01-01

    We present an investigation of the use of net charge and kaon identification to tag the flavor of neutral B mesons. The net charge of the neutral B meson decay products is zero if all charged particles are used and slightly non-zero if only undiscriminated hadronic final states are used. The net charge of the kaons alone correctly tags the identity of the neutral meson in at least a third of all decays. We have parametrized the particle identification capability of several techniques, such as dE/dx in time projection chambers, LEP/SLC ring-imaging chambers and an enhanced BaBar DIRC. Using these parametrisations we compare the relative tagging power of each technique to that of an ideal detector. (8 refs).

  20. Neutral currents in semileptonic reactions

    International Nuclear Information System (INIS)

    Paschos, E.A.

    1975-05-01

    The evidence for weak neutral currents is analyzed in semileptonic reactions with special emphasis on their Lorentz and internal symmetry structure. It is found that present observations are consistent with the expectations of gauge theories, but other possibilities can not be ruled out. Of particular interest in this respect is the presence of a large isoscalar component. The excitation of the Δ-resonance by neutral currents is analyzed, and pion-nucleon mass distributions are presented. Charge asymmetries sensitive to isoscalar-isovector interferences are discussed. (U.S.)

  1. Study of coupled heat and mass transfer during absorption of ...

    Indian Academy of Sciences (India)

    Mayer et al (1987) concluded from their numerical investigation that an excellent heat and mass transfer inside the reaction bed, good thermal contact of the bed material to the bed wall, and high external heat transfer coefficients were the important parameters to make the hydrogen absorption/desorption reaction efficient.

  2. Acoustic absorption by two-level systems in a superconductors

    International Nuclear Information System (INIS)

    Morozov, A.I.; Sizov, A.S.

    1991-01-01

    Contribution to sound absorption and to its rate renormalization, attributed to two-level systems, forming as a result of hydrogen capture by heavy impurities, is found. At that it is supposed that two-level system relaxation rate is defined by single-phonon processes. For superconducting niobium phase estimation for frequency range, where the given supposition is valid, is obtained

  3. Mechanochemical hydrogenation of coal

    Science.gov (United States)

    Yang, Ralph T.; Smol, Robert; Farber, Gerald; Naphtali, Leonard M.

    1981-01-01

    Hydrogenation of coal is improved through the use of a mechanical force to reduce the size of the particulate coal simultaneously with the introduction of gaseous hydrogen, or other hydrogen donor composition. Such hydrogen in the presence of elemental tin during this one-step size reduction-hydrogenation further improves the yield of the liquid hydrocarbon product.

  4. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  5. Study of $\\pi^{-}p$ interactions with neutral final states

    CERN Multimedia

    2002-01-01

    This experiment is a study of the production of neutral particles or states decaying into photons in the reaction $\\pi^{-} + p \\rightarrow M^{0} + n$ at SPS energies. \\\\ \\\\ Special attention is paid to the measurement of the production of heavy particles with hidden quantum numbers and of possible new heavy spinless states decaying into two photons. \\\\ \\\\ The large four-momentum transfer behaviour of binary processes involving known neutral mesons and the production of new meson resonances with high mass and spin will also be studied. Complex multiparticle final states will be analysed as a by-product.\\\\ \\\\ The central unit of the experimental set-up is a 4000 cell Cerenkov hodoscope spectrometer (GAMS) which allows the measurement of the momentum vector of each $\\gamma$ in a multigamma event. \\\\ \\\\ The longitudinal position of the interaction point in the liquid hydrogen target is measured by the Cerenkov light intensity. \\\\ \\\\ A guard system, made of scintillation counters and lead-glass Cerenkov counters, ...

  6. Catalyst support effects on hydrogen spillover

    Science.gov (United States)

    Karim, Waiz; Spreafico, Clelia; Kleibert, Armin; Gobrecht, Jens; Vandevondele, Joost; Ekinci, Yasin; van Bokhoven, Jeroen A.

    2017-01-01

    Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. The phenomenon has been much studied and its occurrence on reducible supports such as titanium oxide is established, yet questions remain about whether hydrogen spillover can take place on nonreducible supports such as aluminium oxide. Here we use the enhanced precision of top-down nanofabrication to prepare controlled and precisely tunable model systems that allow us to quantify the efficiency and spatial extent of hydrogen spillover on both reducible and nonreducible supports. We place multiple pairs of iron oxide and platinum nanoparticles on titanium oxide and aluminium oxide supports, varying the distance between the pairs from zero to 45 nanometres with a precision of one nanometre. We then observe the extent of the reduction of the iron oxide particles by hydrogen atoms generated on the platinum using single-particle in situ X-ray absorption spectromicroscopy applied simultaneously to all particle pairs. The data, in conjunction with density functional theory calculations, reveal fast hydrogen spillover on titanium oxide that reduces remote iron oxide nanoparticles via coupled proton-electron transfer. In contrast, spillover on aluminium oxide is mediated by three-coordinated aluminium centres that also interact with water and that give rise to hydrogen mobility competing with hydrogen desorption; this results in hydrogen spillover about ten orders of magnitude slower than on titanium oxide and restricted to very short distances from the platinum particle. We anticipate that these observations will improve our understanding of hydrogen storage and catalytic reactions involving hydrogen, and that our approach to creating and probing model catalyst systems will provide opportunities for studying the origin of synergistic effects in supported catalysts that combine multiple functionalities.

  7. Agglomeration Versus Localization Of Hydrogen In BCC Fe Vacancies

    International Nuclear Information System (INIS)

    Simonetti, S.; Juan, A.; Brizuela, G.; Simonetti, S.

    2006-01-01

    Severe embrittlement can be produced in many metals by small amounts of hydrogen. The interactions of hydrogen with lattice imperfections are important and often dominant in determining the influence of this impurity on the properties of solids. The interaction between four-hydrogen atoms and a BCC Fe structure having a vacancy has been studied using a cluster model and a semiempirical method. For a study of sequential absorption, the hydrogen atoms were positioned in their energy minima configurations, near to the tetrahedral sites neighbouring the vacancy. VH 2 and VH 3 complexes are energetically the most stables in BCC Fe. The studies about the stability of the hydrogen agglomeration gave as a result that the accumulation is unfavourable in complex vacancy-hydrogen with more than three atoms of hydrogen. (authors)

  8. Hysteresis-free nanoplasmonic pd-au alloy hydrogen sensors

    DEFF Research Database (Denmark)

    Wadell, Carl; Nugroho, Ferry Anggoro Ardy; Lidström, Emil

    2015-01-01

    The recent market introduction of hydrogen fuel cell cars and the prospect of a hydrogen economy have drastically accelerated the need for safe and accurate detection of hydrogen. In this Letter, we investigate the use of arrays of nanofabricated Pd-Au alloy nanoparticles as plasmonic optical...... hydrogen sensors. By increasing the amount of Au in the alloy nanoparticles up to 25 atom %, we are able to suppress the hysteresis between hydrogen absorption and desorption, thereby increasing the sensor accuracy to below 5% throughout the investigated 1 mbar to 1 bar hydrogen pressure range. Furthermore......, we observe an 8-fold absolute sensitivity enhancement at low hydrogen pressures compared to sensors made of pure Pd, and an improved sensor response time to below one second within the 0-40 mbar pressure range, that is, below the flammability limit, by engineering the nanoparticle size....

  9. ITER Neutral Beam Injection System

    International Nuclear Information System (INIS)

    Ohara, Yoshihiro; Tanaka, Shigeru; Akiba, Masato

    1991-03-01

    A Japanese design proposal of the ITER Neutral Beam Injection System (NBS) which is consistent with the ITER common design requirements is described. The injection system is required to deliver a neutral deuterium beam of 75MW at 1.3MeV to the reactor plasma and utilized not only for plasma heating but also for current drive and current profile control. The injection system is composed of 9 modules, each of which is designed so as to inject a 1.3MeV, 10MW neutral beam. The most important point in the design is that the injection system is based on the utilization of a cesium-seeded volume negative ion source which can produce an intense negative ion beam with high current density at a low source operating pressure. The design value of the source is based on the experimental values achieved at JAERI. The utilization of the cesium-seeded volume source is essential to the design of an efficient and compact neutral beam injection system which satisfies the ITER common design requirements. The critical components to realize this design are the 1.3MeV, 17A electrostatic accelerator and the high voltage DC acceleration power supply, whose performances must be demonstrated prior to the construction of ITER NBI system. (author)

  10. Net Neutrality in the Netherlands

    NARCIS (Netherlands)

    van Eijk, N.

    2014-01-01

    The Netherlands is among the first countries that have put specific net neutrality standards in place. The decision to implement specific regulation was influenced by at least three factors. The first was the prevailing social and academic debate, partly due to developments in the United States. The

  11. PLT neutral beam injection systems

    International Nuclear Information System (INIS)

    Menon, M.M.; Barber, G.C.; Blue, C.W.

    1979-01-01

    A brief description of the Princeton Large Torus (PLT) neutral beam injection system is given and its performance characteristics are outlined. A detailed operational procedure is included, as are some tips on troubleshooting. Proper operation of the source is shown to be a crucial factor in system performance

  12. Money neutrality: Rethinking the myth

    Directory of Open Access Journals (Sweden)

    Issaoui Fakhri

    2015-01-01

    Full Text Available Considered as an axiomatic basis of classical, neoclassical, and monetarist theories, the long-run money neutrality assumption does not always seem to be verified. Indeed, in our view, the money, in the sense of M2, can constitute a long-run channel of growth transmission. Thus, this paper examines the long-term relationship among money supply (M2, income (GDP, and prices (CPI. The subprime crisis in 2007 has shown that the demand for money does not only meet motives of transaction, precaution, and speculation but also of fictional or quasi-fictional future demands due to the fact that they are created without real counterparts. The capacity of production systems in developed countries to respond to increases in money supply by creating more wealth, involves the assumption of money neutrality in the long-run. However, in developing countries, the excess of money supply may lead to inflation trends. The present study has confirmed the long-term non-neutrality of money supply in the USA, and its neutrality in Gabon and Morocco.

  13. Laser cooling of neutral atoms

    International Nuclear Information System (INIS)

    1993-01-01

    A qualitative description of laser cooling of neutral atoms is given. Two of the most important mechanisms utilized in laser cooling, the so-called Doppler Cooling and Sisyphus Cooling, are reviewed. The minimum temperature reached by the atoms is derived using simple arguments. (Author) 7 refs

  14. RE: Pedagogy--After Neutrality

    Science.gov (United States)

    I'Anson, John

    2010-01-01

    Within the UK and in many parts of the world, official accounts of what it is to make sense of religion are framed within a rhetorics of neutrality in which such study is premised upon the possibility of dispassionate engagement and analysis. This paper, which is largely theoretical in scope, explores both the affordances and the costs of such an…

  15. Survey of hydrogen monitoring devices

    International Nuclear Information System (INIS)

    Lai, W.

    1981-01-01

    Presented are results of a survey of commercially available monitoring devices suitable for hydrogen detection in the secondary containment vessel of a nuclear power plant during the post postulated accident period. Available detectors were grouped into the following five classes: combustion, solid state, electrochemical, thermal conductivity, and absorption. The performance of most available sensors is likely to deteriorate when exposed to the postulated conditions which include moisture, which could be at high temperature, and radioactive noncondensibles. Of the commercial devices, those using metallic filament thermal conductivity detectors seem least susceptible to performance change. Absorption detectors are best suited for this monitoring task but the only available device is designed for pipeline corrosion assessment. Initiation of experimental study to assess apparent deficiencies of commercial detectors is recommended. Also recommended is an analytical/experimental effort to determine the optimum detector array for monitoring in the secondary containment vessels

  16. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning......Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...

  17. The JET cryopump system and its cryolines for neutral injection

    International Nuclear Information System (INIS)

    Obert, W.; Duessing, G.; Kuessel, E.; Kupschus, P.; Mayaux, C.; Rebut, P.H.

    1984-01-01

    Two large scale Cryopump Systems each with 40 m 2 pumping area and 8 x 10 6 ls -1 pumping speed for hydrogen have been manufactured for neutral injection on JET, and so far one has been successfully tested. The system is based on a 'serial open structure' cryopump configuration developed by JET. The design of the cryopump system had to comply with stringent design requirements as the cryopump system must operate close to the tokamak and in the direct vicinity of the 40 MW power of the Ni-ion beams. (author)

  18. Hydrogenation of polycyclic aromatic hydrocarbons as a factor affecting the cosmic 6.2 micron emission band

    Science.gov (United States)

    Beegle, L. W.; Wdowiak, T. J.; Harrison, J. G.

    2001-01-01

    While many of the characteristics of the cosmic unidentified infrared (UIR) emission bands observed for interstellar and circumstellar sources within the Milky Way and other galaxies, can be best attributed to vibrational modes of the variants of the molecular family known as polycyclic aromatic hydrocarbons (PAH), there are open questions that need to be resolved. Among them is the observed strength of the 6.2 micron (1600 cm(-1)) band relative to other strong bands, and the generally low strength for measurements in the laboratory of the 1600 cm(-1) skeletal vibration band of many specific neutral PAH molecules. Also, experiments involving laser excitation of some gas phase neutral PAH species while producing long lifetime state emission in the 3.3 micron (3000 cm(-1)) spectral region, do not result in significant 6.2 micron (1600 cm(-1)) emission. A potentially important variant of the neutral PAH species, namely hydrogenated-PAH (H(N)-PAH) which exhibit intriguing spectral correlation with interstellar and circumstellar infrared emission and the 2175 A extinction feature, may be a factor affecting the strength of 6.2 micron emission. These species are hybrids of aromatic and cycloalkane structures. Laboratory infrared absorption spectroscopy augmented by density function theory (DFT) computations of selected partially hydrogenated-PAH molecules, demonstrates enhanced 6.2 micron (1600 cm(-1)) region skeletal vibration mode strength for these molecules relative to the normal PAH form. This along with other factors such as ionization or the incorporation of nitrogen or oxygen atoms could be a reason for the strength of the cosmic 6.2 micron (1600 cm(-1)) feature.

  19. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available of hydrogen in metals processing and treatment identified, and mechanisms for hydrogen entry into a ferritic surface are discussed. The differences between hydrogen attack of ferritic steels and copper alloys are contrasted, and an unusual case study...

  20. Theory of direct scattering of neutral and charged atoms

    Science.gov (United States)

    Franco, V.

    1979-01-01

    The theory for direct elastic and inelastic collisions between composite atomic systems formulated within the framework of the Glauber approximation is presented. It is shown that the phase-shift function is the sum of a point Coulomb contribution and of an expression in terms of the known electron-hydrogen-atom and proton-hydrogen-atom phase shift function. The scattering amplitude is reexpressed, the pure Coulomb scattering in the case of elastic collisions between ions is isolated, and the exact optical profile function is approximated by a first-order expansion in Glauber theory which takes into account some multiple collisions. The approximate optical profile function terms corresponding to interactions involving one and two electrons are obtained in forms of Meijer G functions and as a one-dimensional integral, and for collisions involving one or two neutral atoms, the scattering amplitude is further reduced to a simple closed-form expression.

  1. Absorption fluids data survey

    Science.gov (United States)

    Macriss, R. A.; Zawacki, T. S.

    Development of improved data for the thermodynamic, transport and physical properties of absorption fluids were studied. A specific objective of this phase of the study is to compile, catalog and coarse screen the available US data of known absorption fluid systems and publish it as a first edition document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. The methodology and findings of the compilation, cataloguing and coarse screening of the available US data on absorption fluid properties and presents current status and future work on this project are summarized. Both in house file and literature searches were undertaken to obtain available US publications with pertinent physical, thermodynamic and transport properties data for absorption fluids. Cross checks of literature searches were also made, using available published bibliographies and literature review articles, to eliminate secondary sources for the data and include only original sources and manuscripts. The properties of these fluids relate to the liquid and/or vapor state, as encountered in normal operation of absorption equipment employing such fluids, and to the crystallization boundary of the liquid phase, where applicable. The actual data were systematically classified according to the type of fluid and property, as well as temperature, pressure and concentration ranges over which data were available. Data were sought for 14 different properties: Vapor-Liquid Equilibria, Crystallization Temperature, Corrosion Characteristics, Heat of Mixing, Liquid-Phase-Densities, Vapor-Liquid-Phase Enthalpies, Specific Heat, Stability, Viscosity, Mass Transfer Rate, Heat Transfer Rate, Thermal Conductivity, Flammability, and Toxicity.

  2. High-energy photoproduction of neutral mesons

    CERN Document Server

    Charity, Tim

    1987-01-01

    This thesis presents results from the first full period of data-taking of the experiment WA69 at the Omega^'^ectrometer, CERN, Geneva. The experiment used a tagged photon beam of energy 60-180 GeV incident on a liquid hydrogen target to study photoproduction of hadronic states. The various components of the experiment are described, with particular emphasis on the electromagnetic calorimeters, and the associated offline software for event reconstruction and acceptance calculation. The performance of the outer calorimeter is discussed, and the pi^0 detection and reconstruction efficiency is examined by comparison with pi^{+/- } production. Searches for photoproduction of neutral meson states reveal a clear signal for the pi^0, eta^0 , and omega^0 mesons. The cross-section for elastic omega^0 production is estimated, and found to be consistent with the established value of 1 mub. The cross-section for inclusive pi^0 and eta^0 production is studied using the variable Feynman-x (x_{F }), and pi^0 production as a ...

  3. The diagnostic neutral beam system for text

    International Nuclear Information System (INIS)

    Hammond, D.P.; Burgin, D.; Coupland, J.R.; DeVere, A.P.C.; Green, T.S.; Klein, H.H.

    1986-01-01

    The detection of highly stripped impurity ions in a Tokamak plasma by means of charge exchange with a probing neutral beam is an interesting and developing technique. Such a beam system is being designed and manufactured by the Culham Laboratory under contract to the University of Texas at Austin. The specification is for a high brightness beam of hydrogen atoms of 30-50 keV energy with a current density of 30 mA/cm/sup 2/ in the target plane. The pulse length is 100 mS, and the beam has to be capable of being modulated at high frequency (≥ 1 KHz) to improve the overall detection capability of the diagnostic system. The total extracted current at 50 KV is 7.2A. The design has been based on a ''bucket'' type plasma source with a four-electrode extraction array of circular apertures. Low perveance extraction is used to obtain both high brightness and freedom from high voltage breakdown, in view of the high degree of reliability needed. Details of performance of the beam line measured during commissioning tests at Culham are given

  4. Hydrogen absorption/desorption characteristics of room temperature ...

    Indian Academy of Sciences (India)

    Administrator

    site element increases. This trend suggests that ZrCr2 and. ZrMn2 form the most stable hydrides and ZrNi2 forms the least stable hydride. Thus, we ..... Bogdanovic B, Brand R A, Marjanovic A, Schwickardi M and. Tölle J 2000 J. Alloys Compd. 302 36. Douglas G, Ivey, Derek O and Northwood 1996 Z. Phys. Chem. 147 191.

  5. Hydrogen production by absorption enhanced water gas shift (AEWGS)

    Energy Technology Data Exchange (ETDEWEB)

    Escobedo Bretado, Miguel A. [Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Ave. Veterinaria s/n, Circuito Universitario, Durango 34120 (Mexico); Departamento de Quimica de Materiales, Centro de Investigacion en Materiales Avanzados, S.C. Miguel de Cervantes 120, Chihuahua, Chih. 31109 (Mexico); Delgado Vigil, Manuel D.; Gutierrez, Jesus Salinas; Lopez Ortiz, Alejandro; Collins-Martinez, Virginia [Departamento de Quimica de Materiales, Centro de Investigacion en Materiales Avanzados, S.C. Miguel de Cervantes 120, Chihuahua, Chih. 31109 (Mexico)

    2010-11-15

    AEWGS is a reaction that combines the WGS reaction and CO{sub 2} capture by a solid absorbent to produce high purity H{sub 2} from synthesis gas in one single step at 600-800 C. This reactor system, if homogeneous, would not require a catalyst. However, previous research on this concept was not conclusive, since a steel reactor was used and reactor walls were suspected to act as catalyst. Therefore, there is a need to address this issue and to select and evaluate suitable CO{sub 2} absorbents for this concept. AEWGS was studied using a quartz-made fixed-bed reactor at; SV = 3000 h{sup -1}, feed; 5% CO, 15% H{sub 2}O, balance He-N{sub 2} at 600 C, 1 atm. CO{sub 2} absorbents tested were CaO*MgO, and Na{sub 2}ZrO{sub 3}. Empty quartz-reactor tests leaded to conclude that a catalyst is needed for the WGS at temperatures of interest. A 97% H{sub 2} product was obtained with calcined dolomite suggesting this last to act as a WGS catalyst. (author)

  6. Photovoltaic Hydrogen Sensor

    Science.gov (United States)

    Daud, Taher; Janesick, James R.; Lambe, John

    1989-01-01

    Photovoltaic device senses hydrogen developed to test degradation of diodes with platinum flash gates on backs. Sensing element is p/n junction rather than conventional Schottky barrier or metal oxide/silicon field-effect transistor. Hydrogen-indicating electrical signal modulated optically rather than electrically. Layered structure of hydrogen detector and principle of operation resemble silicon solar photovoltaic cell. Hydrogen detector responds to hydrogen in atmosphere within minutes and recovers quickly when hydrogen removed.

  7. Absorption capacity of fructose in healthy adults. Comparison with sucrose and its constituent monosaccharides.

    OpenAIRE

    Rumessen, J J; Gudmand-Høyer, E

    1986-01-01

    The capacity to absorb fructose in 10 healthy adults was investigated by means of hydrogen breath analysis. Fructose absorption was quantified with lactulose standards. Significant hydrogen production (greater than or equal to 20 ppm rise of breath hydrogen) was found after challenge with 10% solutions of 50, 37.5, 25, 20, and 15 g fructose in eight, seven, five, four and one subjects, respectively. One subject showed malabsorption after a 10 g dose and possibly also 5 g fructose. In contrast...

  8. Absorption cooling device. Absorptions-Kuehlvorrichtung

    Energy Technology Data Exchange (ETDEWEB)

    Bourne, J.; Vardi, I.; Kimchi, Y.; Ben-Dror, J.

    1980-03-25

    The invention concerns improvements of absorption refrigerators, where a lithium chloride or lithium bromide/water cycle is used. According to the invention an inner separating or dividing structure between different functional parts of a machine of this type is provided. The structure contains two sections of wall, which are separated from one another by a suitable space, in order to achieve thermal insulation. This air space is provided with an opening in the direction towards the inside of the container and the opening is shielded to prevent the entry of liquids (in liquid or spray form).

  9. Alloying effect on the electronic structures of hydrogen storage compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, H.; Moringa, M.; Takahashi, Y. [Nagoya Univ. (Japan). Dept. of Mater. Sci. and Eng.

    1997-05-20

    The electronic structures of hydrogenated LaNi{sub 5} containing various 3d transition elements were investigated by the DV-X{alpha} molecular orbital method. The hydrogen atom was found to form a strong chemical bond with the Ni rather than the La atoms. The alloying modified the chemical bond strengths between atoms in a small metal octahedron containing a hydrogen atom at the center, resulting in the change in the hydrogen absorption and desorption characteristics of LaNi{sub 5} with alloying. (orig.) 7 refs.

  10. Developments in neutral injection heating

    International Nuclear Information System (INIS)

    Green, T.S.; Coupland, J.R.; Hammond, D.P.; Holmes, A.J.T.; Martin, A.R.; Hemsworth, R.S.; Thompson, E.

    1985-01-01

    Performance data obtained from hydrogen injectors developed for auxiliary heating in JET are given. The injectors have operated at 80 kV with a current of 60 A for pulse lengths of 5 seconds. This beam energy is close to the limit at which positive ion systems are acceptably efficient, owing to the rapid decrease of the charge-exchange cross-section with particle kinetic energy. Higher energy beams may be produced using negative ion beams, due to the large cross-section for electron detachment. An H - source based on volume production in a hydrogen gas discharge is being developed to meet future needs. (author)

  11. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A. L.; Chen, J. E. [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  12. Identification of intrinsic catalytic activity for electrochemical reduction of water molecules to generate hydrogen

    KAUST Repository

    Shinagawa, Tatsuya

    2015-01-01

    Insufficient hydronium ion activities at near-neutral pH and under unbuffered conditions induce diffusion-limited currents for hydrogen evolution, followed by a reaction with water molecules to generate hydrogen at elevated potentials. The observed constant current behaviors at near neutral pH reflect the intrinsic electrocatalytic reactivity of the metal electrodes for water reduction. This journal is © the Owner Societies.

  13. The isotope effect on divertor conditions and neutral pumping in horizontal divertor configurations in JET-ILW Ohmic plasmas

    Directory of Open Access Journals (Sweden)

    J. Uljanovs

    2017-08-01

    Full Text Available Understanding the impact of isotope mass and divertor configuration on the divertor conditions and neutral pressures is critical for predicting the performance of the ITER divertor in DT operation. To address this need, ohmically heated hydrogen and deuterium plasma experiments were conducted in JET with the ITER-like wall in varying divertor configurations. In this study, these plasmas are simulated with EDGE2D-EIRENE outfitted with a sub-divertor model, to predict the neutral pressures in the plenum with similar fashion to the experiments. EDGE2D-EIRENE predictions show that the increased isotope mass results in up to a 25% increase in peak electron densities and 15% increase in peak ion saturation current at the outer target in deuterium when compared to hydrogen for all horizontal divertor configurations. Indicating that a change from hydrogen to deuterium as main fuel decreases the neutral mean free path, leading to higher neutral density in the divertor. Consequently, this mechanism also leads to higher neutral pressures in the sub-divertor. The experimental data provided by the hydrogen and deuterium ohmic discharges shows that closer proximity of the outer strike point to the pumping plenum results in a higher neutral pressure in the sub-divertor. The diaphragm capacitance gauge pressure measurements show that a two to three-fold increase in sub-divertor pressure was achieved in the corner and nearby horizontal configurations compared to the far-horizontal configurations, likely due to ballistic transport (with respect to the plasma facing components of the neutrals into the sub-divertor. The corner divertor configuration also indicates that a neutral expansion occurs during detachment, resulting in a sub-divertor neutral density plateau as a function of upstream density at the outer-mid plane.

  14. Hydrogen embrittlement in nickel-hydrogen cells

    Science.gov (United States)

    Gross, Sidney

    1989-01-01

    It was long known that many strong metals can become weakened and brittle as the result of the accumulation of hydrogen within the metal. When the metal is stretched, it does not show normal ductile properties, but fractures prematurely. This problem can occur as the result of a hydrogen evolution reaction such as corrosion or electroplating, or due to hydrogen in the environment at the metal surface. High strength alloys such as steels are especially susceptible to hydrogen embrittlement. Nickel-hydrogen cells commonly use Inconel 718 alloy for the pressure container, and this also is susceptible to hydrogen embrittlement. Metals differ in their susceptibility to embrittlement. Hydrogen embrittlement in nickel-hydrogen cells is analyzed and the reasons why it may or may not occur are discussed. Although Inconel 718 can display hydrogen embrittlement, experience has not identified any problem with nickel-hydrogen cells. No hydrogen embrittlement problem is expected with the 718 alloy pressure container used in nickel-hydrogen cells.

  15. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    c0, c being the instantaneous concentration at a local point and c0, the average concentration of hydrogen in the hydrogenated amorphous silicon. If the system is both incompressible and isotropic, the change in Helmholtz free energy due to fluctuations in the local concentration of hydrogen is given as. 122. Pramana – J.

  16. Impurity induced neutralization of MeV energy protons in JET plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gondhalekar, A. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Korotkov, A.A. [AF Ioffe Institute, Saint Petersburg (Russian Federation)

    1994-07-01

    A model elucidating the role of carbon and beryllium, the main impurities in JET plasmas, in neutralizing MeV energy protons, which arise during ICRF heating of deuterium plasmas in the hydrogen minority heating mode D(H), and from D-D fusion reactions, is presented. The model establishes charge transfer from hydrogen-like impurity ions to protons as the main process for neutralization. Calculations for deducing the proton energy distribution function from measured hydrogen flux are described. The validity of the model is tested by using it to described the measured flux in different conditions of plasma heating and fueling. Further, it is used to deduce the background thermal deuterium atom density at the plasma center. 9 refs., 6 figs.

  17. Analysis of hydrogen storage in metal hydride tanks introducing an induced phase transformation

    Energy Technology Data Exchange (ETDEWEB)

    Gondor, Germain; Lexcellent, Christian [Institut FEMTO-ST, Departement de Mecanique Appliquee (LMARC), Universite de Franche-Comte, UMR CNRS 6174, 24 Chemin de l' Epitaphe, 25000 Besancon (France)

    2009-07-15

    Hydrogen absorption in a metal hydride tank is generally studied based on a heat and mass transfer analysis. The originality of this investigation is that the phase transformation from a solid ({alpha} phase) to hydride ({beta} phase) solution is included in the hydrogen absorption mechanism. Toward this end, a modelling of the equilibrium pressure, composition (absorbed or desorbed hydrogen atoms per metal atoms), and isothermal curves of a LaNi{sub 5} alloy is performed. Moreover, a kinetic model is developed taking into account the steps of hydrogen absorption and desorption (i.e., physisorption, chemisorption, surface penetration, nucleation and growth of the hydride phase and diffusion). Simulations are then performed to show the impact of external conditions (hydrogen gas pressure and temperature) and parameter values (wall heat transfer, conductivities of gas and solid, viscosity, porosity, etc.) on refilling time. The physical nature of the phase transformation associated to the hydrogen storage remains an open problem. (author)

  18. Vitamin A absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Investigation of the absorption of vitamin A and related substances is complicated by the multiplicity of forms in which they occur in the diet and by the possibility that they may be subject to different mechanisms of absorption. Present knowledge of these mechanisms is inadequate, especially in the case of carotenoids. Numerous tests of absorption have been developed. The most common has been the biochemical measurement of the rise in plasma vitamin A after an oral dose of retinol or retinyl ester, but standardization is inadequate. Radioisotope tests based upon assay of serum or faecal activity following oral administration of tritiated vitamin A derivaties hold considerable promise, but again standardization is inadequate. From investigations hitherto performed it is known that absorption of vitamin A is influenced by several diseases, although as yet the consistency of results and the correlation with other tests of intestinal function have often been poor. However, the test of vitamin A absorption is nevertheless of clinical importance as a specialized measure of intestinal function. (author)

  19. Investigation of hydrogen-deformation interactions in β-21S titanium alloy using thermal desorption spectroscopy

    International Nuclear Information System (INIS)

    Tal-Gutelmacher, E.; Eliezer, D.; Boellinghaus, Th.

    2007-01-01

    The focus of this paper is the investigation of the combined influence of hydrogen and pre-plastic deformation on hydrogen's absorption/desorption behavior, the microstructure and microhardness of a single-phased β-21S alloy. In this study, thermal desorption analyses (TDS) evaluation of various desorption and trapping parameters provide further insight on the relationships between hydrogen absorption/desorption processes and deformation, and their mutual influence on the microstructure and the microhardness of β-21S alloy. TDS spectra were supported by other experimental techniques, such as X-ray diffraction, scanning and transmission electron microscopy, hydrogen quantity analyses and microhardness tests. Pre-plastic deformation, performed before the electrochemical hydrogenation of the alloy, increased significantly the hydrogen absorption capacity. Its influence was also evident on the notably expanded lattice parameter of β-21S alloy after hydrogenation. However, no hydride precipitation was observed. An interesting softening effect of the pre-deformed hydrogenated alloy was revealed by microhardness tests. TDS demonstrated the significant effect of pre-plastic deformation on the hydrogen evolution process. Hydrogen desorption temperature and the activation energy for hydrogen release increased, additional trap states were observed and the amount of desorbed hydrogen decreased

  20. Neutral atom traps of radioactives

    International Nuclear Information System (INIS)

    Behr, J.A.

    2003-01-01

    Neutral atoms trapped with modern laser cooling techniques offer the promise of improving several broad classes of experiments with radioactive isotopes. In nuclear β decay, neutrino spectroscopy from beta-recoil coincidences, along with highly polarized samples, enable experiments to search for non-Standard Model interactions, test whether parity symmetry is maximally violated, and search for new sources of time reversal violation. Ongoing efforts at TRIUMF, Los Alamos and Berkeley will be highlighted. The traps also offer bright sources for Doppler-free spectroscopy, particularly in high-Z atoms where precision measurements could measure the strength of weak neutral nucleon-nucleon and electron-nucleon interactions. Physics with francium atoms has been vigorously pursued at Stony Brook. Several facilities plan work with radioactive atom traps; concrete plans and efforts at KVI Groningen and Legnaro will be among those summarized. Contributions to the multidisciplinary field of trace analysis will be left up to other presenters

  1. Neutral atom traps of radioactives

    CERN Document Server

    Behr, J A

    2003-01-01

    Neutral atoms trapped with modern laser cooling techniques offer the promise of improving several broad classes of experiments with radioactive isotopes. In nuclear beta decay, neutrino spectroscopy from beta-recoil coincidences, along with highly polarized samples, enable experiments to search for non-Standard Model interactions, test whether parity symmetry is maximally violated, and search for new sources of time reversal violation. Ongoing efforts at TRIUMF, Los Alamos and Berkeley will be highlighted. The traps also offer bright sources for Doppler-free spectroscopy, particularly in high-Z atoms where precision measurements could measure the strength of weak neutral nucleon-nucleon and electron-nucleon interactions. Physics with francium atoms has been vigorously pursued at Stony Brook. Several facilities plan work with radioactive atom traps; concrete plans and efforts at KVI Groningen and Legnaro will be among those summarized. Contributions to the multidisciplinary field of trace analysis will be left...

  2. Radiative lifetimes of neutral samarium

    International Nuclear Information System (INIS)

    Den Hartog, E A; Lawler, J E

    2013-01-01

    Radiative lifetimes of 120 odd-parity levels of neutral samarium, ranging in energy from 17 190 to 33 507 cm −1 , are measured using the technique of time-resolved laser-induced fluorescence on a slow atomic beam. This work is part of an ongoing study of radiative properties of rare earth neutral atoms, and is motivated by research needs in astrophysics and lighting technology. This set of Sm i lifetimes substantially increases the available published lifetime data, with 49 of the 120 level lifetimes measured for the first time. These data, most of which are accurate to ±5%, will be combined with branching fractions determined from Fourier transform spectroscopy to produce a large set of measured Sm i transition probabilities. (paper)

  3. Radiative lifetimes of neutral gadolinium

    International Nuclear Information System (INIS)

    Den Hartog, E A; Bilty, K A; Lawler, J E

    2011-01-01

    The current work is part of an ongoing study of radiative properties of rare earth neutral atoms motivated by research needs in several disparate fields including astrophysics, laser chemistry and lighting technology. Time-resolved laser-induced fluorescence on a slow atomic beam has been used to measure radiative lifetimes, accurate to ±5%, for 136 levels of neutral gadolinium. Of the 136 levels, 6 are odd parity ranging in energy from 32 929 to 36 654 cm -1 , and the remaining 130 are even parity ranging from 17 750 to 34 175 cm -1 . This set of Gd i lifetimes represents a significant extension to the available published data, with 93 of the 136 level lifetimes measured for the first time. These lifetimes will provide the absolute normalization for a large set of measured Gd i transition probabilities.

  4. Radiative lifetimes of neutral neodymium

    International Nuclear Information System (INIS)

    Den Hartog, E A; Fittante, A J; Lawler, J E

    2011-01-01

    This work is part of an on-going study of radiative properties of rare earth neutral atoms. This work is motivated by research needs in several disparate fields including astrophysics and lighting technology. Radiative lifetimes of 100 levels of neutral neodymium are measured using the technique of time-resolved laser-induced fluorescence on a slow atomic beam. Of the 100 levels, 3 are even parity ranging in energy from 25 746 to 26 835 cm -1 , and the remaining 97 are odd parity ranging from 17 787 to 27 786 cm -1 . This set of Nd i lifetimes represents a significant extension to the available published data, with 51 of the 100 level lifetimes measured for the first time. These data, which are accurate to ±5%, provide the absolute normalization for a large set of measured Nd i transition probabilities.

  5. Entry and diffusion of electrolytic hydrogen in some surface treated steels

    International Nuclear Information System (INIS)

    Waheed, A.F.M.

    1986-01-01

    Hydrogen diffusion and permeation through metals specially ferrous material is a subject that has a large volume of researches. the most important reason is the technological importance associated with the degradation of ferrous materials resulting from hydrogen absorption. The embrittling effect of hydrogen in steels and the catastrophic nature of failures caused by hydrogen embrittlement has led also to the importance of understanding hydrogen entry and surface processes. the effect of surface treatment of some types of steels on hydrogen entry and diffusion at room temperature (25 degree C) was studied. the two types of steels used in this study are plain carbon steel and low alloy steel

  6. Neutral Pion Photoproduction on Neutron

    Science.gov (United States)

    Bulychev, S. A.; Kudryavtsev, A. E.; Kulikov, V. V.; Martem'yanov, M. A.; Tarasov, V. E.; Briscoe, W. J.; Strakovsky, I. I.

    2017-12-01

    The reaction γ n → π0 n is investigated both theoretically and experimentally as an important step toward determining the electromagnetic coupling constants of the N* and Δ* resonances [1]. We analyze the data on the collisions of γ quanta with energies between 200 and 800 MeV with a deuterium target collected by the A2 experiment in Mainz, Germany. These complement the data for neutral-pion photoproduction on protons obtained by the same experiment [2].

  7. Money neutrality: Rethinking the myth

    OpenAIRE

    Issaoui Fakhri; Boufateh Talel; Guesmi Mourad

    2015-01-01

    Considered as an axiomatic basis of classical, neoclassical, and monetarist theories, the long-run money neutrality assumption does not always seem to be verified. Indeed, in our view, the money, in the sense of M2, can constitute a long-run channel of growth transmission. Thus, this paper examines the long-term relationship among money supply (M2), income (GDP), and prices (CPI). The subprime crisis in 2007 has shown that the demand for money does not only...

  8. Vendor neutral archive in PACS

    International Nuclear Information System (INIS)

    Agarwal, Tapesh Kumar; Sanjeev

    2012-01-01

    An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. “Vendor neutral” may not be a suitable term, and “architecture neutral,” “PACS neutral,” “content neutral,” or “third-party neutral” are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe

  9. Hydrogen converters

    International Nuclear Information System (INIS)

    Mondino, Angel V.

    2003-01-01

    The National Atomic Energy Commission of Argentina developed a process of 99 Mo production from fission, based on irradiation of uranium aluminide targets with thermal neutrons in the RA-3 reactor of the Ezeiza Atomic Centre. These targets are afterwards dissolved in an alkaline solution, with the consequent liberation of hydrogen as the main gaseous residue. This work deals with the use of a first model of metallic converter and a later prototype of glass converter at laboratory scale, adjusted to the requirements and conditions of the specific redox process. Oxidized copper wires were used, which were reduced to elementary copper at 400 C degrees and then regenerated by oxidation with hot air. Details of the bed structure and the operation conditions are also provided. The equipment required for the assembling in cells is minimal and, taking into account the operation final temperature and the purge with nitrogen, the procedure is totally safe. Finally, the results are extrapolated for the design of a converter to be used in a hot cell. (author)

  10. Oxygen diluted hexamethyldisiloxane plasmas investigated by means of in situ infrared absorption spectroscopy and mass spectrometry

    Science.gov (United States)

    Magni, D.; Deschenaux, Ch; Hollenstein, Ch; Creatore, A.; Fayet, P.

    2001-01-01

    The gas phase species produced in rf plasmas of hexamethyldisiloxane (HMDSO), Si2O(CH3)6, diluted with oxygen, have been investigated. The complementarity of Fourier transform infrared absorption spectroscopy and mass spectrometry allows the determination of the most abundant neutral components present in the discharge. The measurements reveal that methyl groups (CH3), abundantly formed by the dissociation of the HMDSO molecule, are the precursor for the most abundant species which stem from two kinds of reaction. The first kind of reaction is combustion of CH3 by oxygen-producing formaldehyde (COH2), formic acid (CO2H2), carbon monoxide (CO), carbon dioxide (CO2) and water. It is shown that high mass carbonated radicals, such as SixOyCzHt, first diffuse to the surface and then the carbon is removed by oxygen etching to form CO2. The second is hydrocarbon chemistry promoted by CH3, producing mainly hydrogen (H2), methane (CH4) and acetylene (C2H2).

  11. Gastrointestinal absorption of plutonium

    International Nuclear Information System (INIS)

    Larsen, R.P.; Oldham, R.D.; Bhattacharyya, M.H.; Moretti, E.S.; Austin, D.J.

    1981-01-01

    An investigation has been made of the effect of the oxidation state of plutonium on its absorption from the gastrointestinal tract. For mice and rats that have been starved prior to gastrointestinal administration, there is no significant difference between the absorption factors for Pu(IV) and Pu(VI). The value obtained for Pu(VI) is an order of magnitude lower than that reported previously. The value obtained for Pu(IV) is two orders of magnitude higher than those reported previously for nitrate solutions and the same as those reported for citrate solutions

  12. Quantum Absorption Refrigerator

    Science.gov (United States)

    Levy, Amikam; Kosloff, Ronnie

    2012-02-01

    A quantum absorption refrigerator driven by noise is studied with the purpose of determining the limitations of cooling to absolute zero. The model consists of a working medium coupled simultaneously to hot, cold, and noise baths. Explicit expressions for the cooling power are obtained for Gaussian and Poisson white noise. The quantum model is consistent with the first and second laws of thermodynamics. The third law is quantified; the cooling power Jc vanishes as Jc∝Tcα, when Tc→0, where α=d+1 for dissipation by emission and absorption of quanta described by a linear coupling to a thermal bosonic field, where d is the dimension of the bath.

  13. TEARING THE VEIL: INTERACTION OF THE ORION NEBULA WITH ITS NEUTRAL ENVIRONMENT

    International Nuclear Information System (INIS)

    Van der Werf, Paul P.; Goss, W. M.; O'Dell, C. R.

    2013-01-01

    We present H I 21 cm observations of the Orion Nebula, obtained with the Karl G. Jansky Very Large Array, at an angular resolution of 7.''2 × 5.''7 and a velocity resolution of 0.77 km s –1 . Our data reveal H I absorption in the Veil toward the radio continuum of the H II region, and H I emission arising from the Orion Bar photon-dominated region (PDR) and from the Orion-KL outflow. In the Orion Bar PDR, the H I signal peaks in the same layer as the H 2 near-infrared vibrational line emission, in agreement with models of the photodissociation of H 2 . The gas temperature in this region is approximately 540 K, and the H I abundance in the interclump gas in the PDR is 5%-10% of the available hydrogen nuclei. Most of the gas in this region therefore remains molecular. Mechanical feedback on the Veil manifests itself through the interaction of ionized flow systems in the Orion Nebula, in particular the Herbig-Haro object HH 202, with the Veil. These interactions give rise to prominent blueward velocity shifts of the gas in the Veil. The unambiguous evidence for interaction of this flow system with the Veil shows that the distance between the Veil and the Trapezium stars needs to be revised downward to about 0.4 pc. The depth of the ionized cavity is about 0.7 pc, which is much smaller than the depth and the lateral extent of the Veil. Our results reaffirm the blister model for the M42 H II region, while also revealing its relation to the neutral environment on a larger scale.

  14. A hydrogen ice cube

    NARCIS (Netherlands)

    Peters, C.J.; Schoonman, J.; Schrauwers, A.

    2004-01-01

    Hydrogen is considered to be a highly promising energy carrier. Nonetheless, before hydrogen can become the fuel of choice for the future a number of slight problems will have to be overcome. For example, how can hydrogen be safely stored? Motor vehicles running on hydrogen may be clean in concept

  15. Determination of the neutral to charged current cross section ratio for neutrino interactions on protons

    Energy Technology Data Exchange (ETDEWEB)

    Armenise, N.; Calicchio, M.; Erriquez, O.; Fogli-Muciaccia, M.T.; Natali, S.; Nuzzo, S.; Ruggieri, F. (Bari Univ. (Italy). Ist. di Fisica; Istituto Nazionale di Fisica Nucleare, Bari (Italy)); Belusevic, R.; Colley, D.C.

    1983-03-17

    About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC have been analysed. The data were obtained from an exposure to the vsub(..mu..) wide band beam at the CERN SPS. A separation of these events into charged current, neutral current and neutral hadron induced interactions have been achieved using a multidimensional kinematic analysis. The neutral to charged current cross section ratio for vsub(..mu..) interactions on free protons has been determined avoiding the drastic cuts on the data inherent in previous experiments. The result Rsub(P)sup(v)=0.47 +- 0.04 is compatible with those measurements and the prediction of the standard SU(2) x U(1) model for sinsub(THETA)/sup 2/sub(W)=0.18 +- 0.04.

  16. Determination of the neutral to charged current cross section ratio for neutrino interactions on protons

    Science.gov (United States)

    Armenise, N.; Calicchio, M.; Erriquez, O.; Fogli-Muciaccia, M. T.; Natali, S.; Nuzzo, S.; Ruggieri, F.; Belusevic, R.; Colley, D. C.; Jones, G. T.; O'Neale, S.; Sewell, S.; Votruba, M. F.; Bertrand, D.; Moreels, J.; Sacton, J.; Vander Velde-Wilquet, C.; Van Doninck, W.; Brisson, V.; Francois, T.; Petiau, P.; Cooper, A. M.; Guy, J. G.; Michette, A. G.; Tyndel, M.; Venus, W.; Baton, J. P.; Gerbier, G.; Kochowski, C.; Neveu, M.; Alamatsaz, H.; Azemoon, T.; Bartley, J. H.; Parker, M. A.; BEBC TST Neutrino Collaboration

    1983-03-01

    About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC have been analysed. The data were obtained from an exposure to the vμ wide band beam at the CERN SPS. A separation of these events into charged current, neutral current and neutral hadron induced interactions have been achieved using a multidimensional kinematic analysis. The neutral to charged current cross section ratio for vμ interactions on free protons has been determined avoiding the drastic cuts on the data inherent in previous experiments. The result RPv = 0.47 ± 0.04 is compatible with those measurements and the prediction of the standard SU (2) × U (1) model for sin 2θW = 0.18 ± 0.04.

  17. Probing the structures of neutral boron clusters using infrared/vacuum ultraviolet two color ionization: B[sub 11], B[sub 16], and B[sub 17

    NARCIS (Netherlands)

    Romanescu, C.; Harding, D. J.; Fielicke, A.; Wang, L. S.

    2012-01-01

    The structures of neutral boron clusters, B11, B16, and B17, have been investigated using vibrational spectroscopy and ab initio calculations. Infrared absorption spectra in the wavelength range of 650 to 1550 cm−1 are obtained for the three neutral boron clusters from the enhancement of their

  18. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  19. Fiber optic hydrogen sensor

    Science.gov (United States)

    Buchanan, B.R.; Prather, W.S.

    1991-01-01

    Apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading, by a single spectrophotometer.

  20. Electric arc hydrogen heaters

    International Nuclear Information System (INIS)

    Zasypin, I.M.

    2000-01-01

    The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

  1. Ion-beam Plasma Neutralization Interaction Images

    Energy Technology Data Exchange (ETDEWEB)

    Igor D. Kaganovich; Edward Startsev; S. Klasky; Ronald C. Davidson

    2002-04-09

    Neutralization of the ion beam charge and current is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because the excitation of nonlinear plasma waves may occur. Computer simulation images of plasma neutralization of the ion beam pulse are presented.

  2. Neutral beamline with improved ion energy recovery

    Science.gov (United States)

    Kim, Jinchoon

    1984-01-01

    A neutral beamline employing direct energy recovery of unneutralized residual ions is provided which enhances the energy recovery of the full energy ion component of the beam exiting the neutralizer cell, and thus improves the overall neutral beamline efficiency. The unneutralized full energy ions exiting the neutralizer are deflected from the beam path and the electrons in the cell are blocked by a magnetic field applied transverse to the beam direction in the neutral izer exit region. The ions which are generated at essentially ground potential and accelerated through the neutralizer cell by a negative acceleration voltage are collected at ground potential. A neutralizer cell exit end region is provided which allows the magnetic and electric fields acting on the exiting ions to be loosely coupled. As a result, the fractional energy ions exiting the cell are reflected onto and collected at an interior wall of the neutralizer formed by the modified end geometry, and thus do not detract from the energy recovery efficiency of full energy ions exiting the cell. Electrons within the neutralizer are prevented from exiting the neutralizer end opening by the action of crossed fields drift (ExB) and are terminated to a collector collar around the downstream opening of the neutralizer. The correct combination of the extended neutralizer end structure and the magnet region is designed so as to maximize the exit of full energy ions and to contain the fractional energy ions.

  3. Differences between Doppler velocities of ions and neutral atoms in a solar prominence

    Science.gov (United States)

    Anan, T.; Ichimoto, K.; Hillier, A.

    2017-05-01

    Context. In astrophysical systems with partially ionized plasma, the motion of ions is governed by the magnetic field while the neutral particles can only feel the magnetic field's Lorentz force indirectly through collisions with ions. The drift in the velocity between ionized and neutral species plays a key role in modifying important physical processes such as magnetic reconnection, damping of magnetohydrodynamic waves, transport of angular momentum in plasma through the magnetic field, and heating. Aims: This paper aims to investigate the differences between Doppler velocities of calcium ions and neutral hydrogen in a solar prominence to look for velocity differences between the neutral and ionized species. Methods: We simultaneously observed spectra of a prominence over an active region in H I 397 nm, H I 434 nm, Ca II 397 nm, and Ca II 854 nm using a high dispersion spectrograph of the Domeless Solar Telescope at Hida observatory. We compared the Doppler velocities, derived from the shift of the peak of the spectral lines presumably emitted from optically-thin plasma. Results: There are instances when the difference in velocities between neutral atoms and ions is significant, for example 1433 events ( 3% of sets of compared profiles) with a difference in velocity between neutral hydrogen atoms and calcium ions greater than 3σ of the measurement error. However, we also found significant differences between the Doppler velocities of two spectral lines emitted from the same species, and the probability density functions of velocity difference between the same species is not significantly different from those between neutral atoms and ions. Conclusions: We interpreted the difference of Doppler velocities as being a result of the motions of different components in the prominence along the line of sight, rather than the decoupling of neutral atoms from plasma. The movie attached to Fig. 1 is available at http://www.aanda.org

  4. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  5. Neutron resonance absorption theory

    International Nuclear Information System (INIS)

    Reuss, P.

    1991-11-01

    After some recalls on the physics of neutron resonance absorption during their slowing down, this paper presents the main features of the theoretical developments performed by the french school of reactor physics: the effective reaction rate method so called Livolant-Jeanpierre theory, the generalizations carried out by the author, and the probability table method [fr

  6. A model of hydrogen impact induced chemical erosion of carbon based on elementary reaction steps

    International Nuclear Information System (INIS)

    Wittmann, M.; Kueppers, J.

    1996-01-01

    Based on the elementary reaction steps for chemical erosion of carbon by hydrogen a model is developed which allows to calculate the amount of carbon erosion at a hydrogenated carbon surface under the impact of hydrogen ions and neutrals. Hydrogen ion and neutral flux energy distributions prevailing at target plates in the ASDEX upgrade experiment are chosen in the present calculation. The range of hydrogen particles in the target plates is calculated using TRIDYN code. Based upon the TRIDYN results the extent of the erosion reaction as a function of depth is estimated. The results show that both, target temperature and impinging particle flux energy distribution, determine the hydrogen flux density dependent erosion yield and the location of the erosion below the surface. (orig.)

  7. Enhancement of the neutral-beam stopping cross section in fusion plasmas due to multistep collision processes

    International Nuclear Information System (INIS)

    Boley, C.D.; Janev, R.K.; Post, D.E.

    1983-10-01

    Multistep processes involving excited atomic states are found to produce a substantial increase in the stopping cross section for a neutral hydrogen beam injected into a plasma, and thus to reduce the beam penetration. For typical plasma and beam parameters of current large tokamak experiments, the stopping cross-sectional enhancement is found to vary from 25% to 50% depending on the beam energy, plasma density, and impurity level. For neutral hydrogen beams with energies greater than or equal to 500 keV, envisioned in tokamak amd mirror reactor designs, the enhancement can be as large as 80 to 90%

  8. Low-energy neutral atom emission from the Earth's magnetosphere

    International Nuclear Information System (INIS)

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

    1994-01-01

    Imaging of the terrestrial magnetosphere is possible through the detection of low-energy neutral atoms (LENAs) produced by charge exchange between magnetospheric plasma ions and neutral atoms of the Earth's geocorona. The authors present calculations of both hydrogen and oxygen line-of-sight LENA fluxes expected on orbit for various plasma regimes as predicted by the Rice University Magnetospheric Specification Model. To decrease the required computation time, they are in the process of adapting their code for massively parallel computers. The speed gains achieved from parallel algorithms are substantial, and they present results from computational runs on the Connection Machine CM-2 data parallel supercomputer. They also estimate expected image count rates and image quality based on realistic instrument geometric factors, energy passbands, neutral atom scattering in the instrument, and image accumulation intervals. The results indicate that LENA imaging instruments will need a geometric factor (G) on the order of 0.1 cm 2 sr eV/eV to be capable of imaging storm time ring currents, and a G of 1.0 cm 2 sr eV/eV in order to image the quiet time ring current fluxes, ion injections from the tail, and subsequent ion drifts toward the dayside magnetopause

  9. Energy recovery in high energy neutral beam injectors

    International Nuclear Information System (INIS)

    Laffite, S.

    1991-07-01

    One way to heat the plasma of thermonuclear fusion experiments, is to inject high energy (50 to 100 KeV per nucleon), neutral particles (hydrogen or deuterium). Neutral beam elaboration consists in ion production and acceleration, neutralisation by charge exchange on gas target, disposal of unneutralized ions. But, in the case of positive ion based neutral beam injection, the neutralisation efficiency is limited to 50% at 100 KeV, and decreases rapidly with energy. The energy recovery is a new method for disposing of the unneutralized ions: these are electrostatically decelerated and collected on electrodes which are polarized at low voltage, close to the ion source potential. An energy recovery system was studied and experimented with positive ion beams of 50 and 100 KeV. In the framework of a french-japanese collaboration, we measured a relative power reduction of about 20%, with 100 KeV, 1,5 MW deuterium beams. We have also studied theoretically an energy recovery system for negative ion beams, which will be utilized at high energy (1 MeV). A relative power reduction of 20% can be expected in the best conditions [fr

  10. Programmable controller--a versatile tool for neutral beam control

    International Nuclear Information System (INIS)

    Campbell, G.L.; Haskovec, J.S.; Moore, C.D.

    1983-01-01

    In neutral beam systems (NB) for the Doublet III fusion experiment at GA Technologies Inc., programmable controllers (PC) are successfully used both on the local and the central levels of control. The local level of control is concentrated in the control instrumentation station (CI), located near the neutral beam tank and its instrumentation. The CI station contains one PC which performs control functions for vacuum, hydrogen, cooling water, automatic cryopanel defrost and recovery from power failure. The CI PC provides interface functions to other local control devices as well as to the NB control computer and central level of control. On the central level the PC creates the main part of a mode control system (MC). It supports mode control panels which serve as global control interface to NB operator, coordinates the operation of NB power supplies, central timing system, neutral beam and tokamak control computers. After a brief exposition of typical functions the implication of requirements such as expandability, reliability and versatility on hardware configuration and program structure will be explained. Results of analysis and tests of time-critical functions will be presented. Finally some aspects of interfaces to different instruments and devices will be described

  11. Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations

    Energy Technology Data Exchange (ETDEWEB)

    Swaczyna, Paweł; Grzedzielski, Stan; Bzowski, Maciej, E-mail: pswaczyna@cbk.waw.pl [Space Research Centre of the Polish Academy of Sciences (CBK PAN), Bartycka 18A, 00-716 Warsaw (Poland)

    2017-05-10

    Observations of energetic neutral atoms (ENAs) allow for remote sensing of plasma properties in distant regions of the heliosphere. So far, most of the observations have concerned only hydrogen atoms. In this paper, we present perspectives for observations of helium energetic neutral atoms (He ENAs). We calculated the expected intensities of He ENAs created by the neutralization of helium ions in the inner heliosheath and through the secondary ENA mechanism in the outer heliosheath. We found that the dominant source region for He ENAs is the inner heliosheath. The obtained magnitudes of intensity spectra suggest that He ENAs can be observed with future ENA detectors, as those planned on Interstellar Mapping and Acceleration Probe . Observing He ENAs is most likely for energies from a few to a few tens of keV/nuc. Estimates of the expected count rates show that the ratio of helium to hydrogen atoms registered in the detectors can be as low as 1:10{sup 4}. Consequently, the detectors need to be equipped with an appropriate mass spectrometer capability, allowing for recognition of chemical elements. Due to the long mean free paths of helium ions in the inner heliosheath, He ENAs are produced also in the distant heliospheric tail. This implies that observations of He ENAs can resolve its structure, which seems challenging from observations of hydrogen ENAs since energetic protons are neutralized before they progress deeper in the heliospheric tail.

  12. Interactions of atomic hydrogen with amorphous SiO2

    Science.gov (United States)

    Yue, Yunliang; Wang, Jianwei; Zhang, Yuqi; Song, Yu; Zuo, Xu

    2018-03-01

    Dozens of models are investigated by the first-principles calculations to simulate the interactions of an atomic hydrogen with a defect-free random network of amorphous SiO2 (a-SiO2) and oxygen vacancies. A wide variety of stable configurations are discovered due to the disorder of a-SiO2, and their structures, charges, magnetic moments, spin densities, and density of states are calculated. The atomic hydrogen interacts with the defect-free a-SiO2 in positively or negatively charged state, and produces the structures absent in crystalline SiO2. It passivates the neutral oxygen vacancies and generates two neutral hydrogenated E‧ centers with different Si dangling bond projections. Electron spin resonance parameters, including Fermi contacts, and g-tensors, are calculated for these centers. The atomic hydrogen interacts with the positive oxygen vacancies in dimer configuration, and generate four different positive hydrogenated defects, two of which are puckered like the Eγ‧ centers. This research helps to understand the interactions between an atomic hydrogen, and defect-free a-SiO2 and oxygen vacancies, which may generate the hydrogen-complexed defects that play a key role in the degeneration of silicon/silica-based microelectronic devices.

  13. Space station neutral external environment

    Science.gov (United States)

    Ehlers, H.; Leger, L.

    1988-01-01

    Molecular contamination levels arising from the external induced neutral environment of the Space Station (Phase 1 configuration) were calculated using the MOLFLUX model. Predicted molecular column densities and deposition rates generally meet the Space Station contamination requirements. In the doubtful cases of deposition due to materials outgassing, proper material selection, generally excluding organic products exposed to the external environment, must be considered to meet contamination requirements. It is important that the Space Station configuration, once defined, is not significantly modified to avoid introducing new unacceptable contamination sources.

  14. Hydrogen bonding in oxalic acid and its complexes: A database ...

    Indian Academy of Sciences (India)

    –COOH as an acceptor in the case of biomolecules was carried out by Ramanad- ham and coworkers [4]. A method was proposed to distinguish between ionized and neutral carboxyl group based on hydrogen bonding properties of OH of COOH. A more general survey of all the carboxylic acid structures determined using ...

  15. reaction process simulation of hydrogen gas discharge in a cold ...

    Indian Academy of Sciences (India)

    +. 3 ions produced. As discussed above, there are 21 reactions in pure hydrogen plasma. But by theoretical analysis, when pressure is low (P < 0.133 Pa), we can eliminate the existence of H. +. 3 ; the reaction between H. +. 3 and neutral molecules does not exist. And because the wall recombination reaction is related to H.

  16. Strontium D-Glutamate Hexahydrate and Strontium Di(hydrogen L-glutamate) Pentahydrate

    DEFF Research Database (Denmark)

    Christgau, Stephan; Odderhede, Jette; Stahl, Kenny

    2005-01-01

    Sr(C5H7NO4)] center dot 6H(2)O, ( I), and [Sr(C5H8NO4)(2)] center dot 5H(2)O, (II), both crystallize with similar strontium - glutamate - water layers. In ( I), the neutral layers are connected through hydrogen bonds by water molecules, while in ( II), the positively charged layers are connected...... through hydrogen bonds and electrostatic interactions by interleaving layers of hydrogen glutamate anions and water molecules....

  17. Thermogravimetric measurement of hydrogen storage in carbon-based materials: promise and pitfalls

    International Nuclear Information System (INIS)

    Pinkerton, F.E.; Wicke, B.G.; Olk, C.H.; Tibbetts, G.G.; Meisner, G.P.; Meyer, M.S.; Herbst, J.F.

    2000-01-01

    We have used a thermogravimetric analyzer (TGA) to measure the hydrogen absorption capacity of a variety of carbon-based storage materials, including Li- and K-intercalated graphite and Li-doped multi-wall nanotubes. The TGA uses weight gain/loss as a function of time and temperature to monitor hydrogen absorption/desorption in flowing hydrogen gas. Creating and maintaining a contaminant-free atmosphere is critical to the accurate TGA measurement of hydrogen absorption in carbon-based materials; even low concentrations of impurity gases such as O 2 or H 2 O are sufficient to masquerade as hydrogen absorption. We will discuss examples of this effect relevant to recent reports of hydrogen storage appearing in the literature. The precautions required are non-trivial. In our TGA, for instance, about 16% of the original atmosphere remains after a two-hour purge; at least 15 hours is required to fully purge the apparatus. Furthermore, we cover the TGA with a protective atmosphere enclosure during sample loading to minimize the introduction of impurity gases. With these precautions it is possible to unambiguously measure hydrogen storage. For example, we have determined the hydrogen absorption capacity of our K-intercalated graphite samples to be 1.3 wt% total hydrogen absorption above 50 o C, of which 0.2 wt% can be reproducibly recovered with temperature cycling. With due care, TGA measurements provide complementary information to that obtained from standard pressure techniques for measuring hydrogen sorption, which rely on measuring the loss of gas pressure in a known volume. Taken together, TGA and pressure measurements provide a powerful combination for determining verifiable hydrogen storage capacity. (author)

  18. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  19. Exceptional Optoelectronic Properties of Hydrogenated Bilayer Silicene

    Directory of Open Access Journals (Sweden)

    Bing Huang

    2014-05-01

    Full Text Available Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and double-sided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, high-efficiency, optoelectronic applications.

  20. Hydrogen Induced Cracking of Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    G. De

    2003-02-24

    One potential failure mechanism for titanium and its alloys under repository conditions is via the absorption of atomic hydrogen in the metal crystal lattice. The resulting decreased ductility and fracture toughness may lead to brittle mechanical fracture called hydrogen-induced cracking (HIC) or hydrogen embrittlement. For the current design of the engineered barrier without backfill, HIC may be a problem since the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this scientific analysis and modeling activity is to evaluate whether the drip shield will fail by HIC or not under repository conditions within 10,000 years of emplacement. This Analysis and Model Report (AMR) addresses features, events, and processes related to hydrogen induced cracking of the drip shield. REV 00 of this AMR served as a feed to ''Waste Package Degradation Process Model Report'' and was developed in accordance with the activity section ''Hydrogen Induced Cracking of Drip Shield'' of the development plan entitled ''Analysis and Model Reports to Support Waste Package PMR'' (CRWMS M&O 1999a). This AMR, prepared according to ''Technical Work Plan for: Waste Package Materials Data Analyses and Modeling'' (BSC 2002), is to feed the License Application.