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Sample records for rf-driven negative hydrogen

  1. Operation of RF driven negative ion source in a pure-hydrogen mode

    SciTech Connect

    Abdrashitov, G.; Belchenko, Yu. Gusev, I.; Senkov, D.; Sanin, A.; Shikhovtsev, I.; Kondakov, A.; Ivanov, A. A.; Sotnikov, O.

    2015-04-08

    The production of negative hydrogen ions in the radio-frequency driven long-pulsed source with external antenna is studied. RF drivers with various geometry of external antenna, Faraday shield and magnets at the rear flange were examined. H- beam extraction through the single emission aperture was performed in the source pure-hydrogen mode with no external seed of alkali additives. H- beam with ion emission current density up to 5 mA/cm{sup 2} and energy up to 75 keV was regularly obtained in the 1 s pulses of the pure-hydrogen mode. The regular temporal increase of H- ion production due to deposition of impurities on the plasma grid surface was recorded. The H- emission current density increased up to 9 mA/cm{sup 2} in this case.

  2. Performance of multi-aperture grid extraction systems for an ITER-relevant RF-driven negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Franzen, P.; Gutser, R.; Fantz, U.; Kraus, W.; Falter, H.; Fröschle, M.; Heinemann, B.; McNeely, P.; Nocentini, R.; Riedl, R.; Stäbler, A.; Wünderlich, D.

    2011-07-01

    The ITER neutral beam system requires a negative hydrogen ion beam of 48 A with an energy of 0.87 MeV, and a negative deuterium beam of 40 A with an energy of 1 MeV. The beam is extracted from a large ion source of dimension 1.9 × 0.9 m2 by an acceleration system consisting of seven grids with 1280 apertures each. Currently, apertures with a diameter of 14 mm in the first grid are foreseen. In 2007, the IPP RF source was chosen as the ITER reference source due to its reduced maintenance compared with arc-driven sources and the successful development at the BATMAN test facility of being equipped with the small IPP prototype RF source ( {\\sim}\\frac{1}{8} of the area of the ITER NBI source). These results, however, were obtained with an extraction system with 8 mm diameter apertures. This paper reports on the comparison of the source performance at BATMAN of an ITER-relevant extraction system equipped with chamfered apertures with a 14 mm diameter and 8 mm diameter aperture extraction system. The most important result is that there is almost no difference in the achieved current density—being consistent with ion trajectory calculations—and the amount of co-extracted electrons. Furthermore, some aspects of the beam optics of both extraction systems are discussed.

  3. Efficient cesiation in RF driven surface plasma negative ion source.

    PubMed

    Belchenko, Yu; Ivanov, A; Konstantinov, S; Sanin, A; Sotnikov, O

    2016-02-01

    Experiments on hydrogen negative ions production in the large radio-frequency negative ion source with cesium seed are described. The system of directed cesium deposition to the plasma grid periphery was used. The small cesium seed (∼0.5 G) provides an enhanced H(-) production during a 2 month long experimental cycle. The gradual increase of negative ion yield during the long-term source runs was observed after cesium addition to the source. The degraded H(-) production was recorded after air filling to the source or after the cesium washing away from the driver and plasma chamber walls. The following source conditioning by beam shots produces the gradual recovery of H(-) yield to the high value. The effect of H(-) yield recovery after cesium coverage passivation by air fill was studied. The concept of cesium coverage replenishment and of H(-) yield recovery due to sputtering of cesium from the deteriorated layers is discussed. PMID:26932015

  4. Optical emission spectroscopy at the large RF driven negative ion test facility ELISE: Instrumental setup and first results

    SciTech Connect

    Wünderlich, D.; Fantz, U.; Franzen, P.; Riedl, R.; Bonomo, F.

    2013-09-15

    One of the main topics to be investigated at the recently launched large (A{sub source}= 1.0 × 0.9 m{sup 2}) ITER relevant RF driven negative ion test facility ELISE (Extraction from a Large Ion Source Experiment) is the connection between the homogeneity of the plasma parameters close to the extraction system and the homogeneity of the extracted negative hydrogen ion beam. While several diagnostics techniques are available for measuring the beam homogeneity, the plasma parameters are determined by optical emission spectroscopy (OES) solely. First OES measurements close to the extraction system show that without magnetic filter field the vertical profile of the plasma emission is more or less symmetric, with maxima of the emission representing the projection of the plasma generation volumes, and a distinct minimum in between. The profile changes with the strength of the magnetic filter field but under all circumstances the plasma emission in ELISE is much more homogeneous compared to the smaller IPP prototype sources. Planned after this successful demonstration of the ELISE OES system is to combine OES with tomography in order to determine locally resolved values for the plasma parameters.

  5. Operation of a cw rf driven ion source with hydrogen and deuterium gas{sup a}

    SciTech Connect

    Melnychuk, S.T.; Debiak, T.W.; Sredniawski, J.J.

    1996-04-01

    We will describe the operation of a cw rf driven multicusp ion source designed for extraction of high current hydrogen and deuterium beams. The source is driven at 2 MHz by a 2.5 turn induction antenna immersed in the plasma. Bare stainless-steel and porcelain-coated Cu antennas have been used. The plasma load is matched to the rf generator by a variable tap {ital N}:1 transformer isolated to 46 kV, and an LC network on the secondary. With H{sub 2} gas the source can be operated at pressures between 5 and 60 mT with power reflection coefficients {lt}0.01. The extracted ion current density with a porcelain-coated antenna is approximately given by 35 mA/cm{sup 2}/kW with an 80 G dipole filter field for input powers from 3.5 to 6.6 kW. The current density remained constant for operation with a 6 and an 8 mm aperture. The source has been operated for 260 h at 3.6 kW with a single-porcelain-coated antenna. Mass spectrometer measurements of the extracted beam at this power show a species mix for H{sup +}:H{sup +}{sub 2}:H{sup +}{sub 3}:OH{sup +} of 0.49: 0.04: 0.42: 0.04. The calculated beam divergence using the IGUN code is compared with the measured divergence from an electrostatic sweep emittance scanner designed for high-power cw beam diagnostics. Phase space measurements at 40 kV and 23 mA beam current result in a normalized rms emittance of 0.09 {pi}mmmrad. {copyright} {ital 1996 American Institute of Physics.}

  6. Operation of a cw rf driven ion source with hydrogen and deuterium gas (abstract){sup a}

    SciTech Connect

    Melnychuk, S.T.; Debiak, T.W.; Sredniawski, J.J.

    1996-03-01

    We will describe the operation of a cw rf driven multicusp ion source designed for extraction of high current hydrogen and deuterium beams. The source is driven at 2 MHz by a 2.5 turn induction antenna immersed in the plasma. Bare stainless-steel and porcelain-coated Cu antennas have been used. The plasma load is matched to the rf generator by a variable tap {ital N}:1 transformer isolated to 46 kV, and an LC network on the secondary. With H{sub 2} gas the source can be operated at pressures between 5 and 60 mT with power reflection coefficients {lt}0.01. The extracted ion current density with a porcelain-coated antenna is approximately given by 35 mA/cm{sup 2}/kW with an 80 G dipole filter field for input powers from 3.5 to 6.6 kW. The current density remained constant for operation with a 6 and an 8 mm aperture. The source has been operated for 260 h at 3.6 kW with a single-porcelain-coated antenna. Mass spectrometer measurements of the extracted beam at this power show a species mix for H{sup +}:H{sup +}{sub 2}:H{sup +}{sub 3}:OH{sup +} of 0.49: 0.04: 0.42: 0.04. The calculated beam divergence using the IGUN code is compared with the measured divergence from an electrostatic sweep emittance scanner designed for high-power cw beam diagnostics. Phase space measurements at 40 kV and 23 mA beam current result in a normalized rms emittance of 0.09 {pi}mmmrad. {copyright} {ital 1996 American Institute of Physics.}

  7. Status of the RF-driven H⁻ ion source for J-PARC linac.

    PubMed

    Oguri, H; Ohkoshi, K; Ikegami, K; Takagi, A; Asano, H; Ueno, A; Shibata, T

    2016-02-01

    For the upgrade of the Japan Proton Accelerator Research Complex linac beam current, a cesiated RF-driven negative hydrogen ion source was installed during the 2014 summer shutdown period, with subsequent operations commencing on September 29, 2014. The ion source has been successfully operating with a beam current and duty factor of 33 mA and 1.25% (500 μs and 25 Hz), respectively. The result of recent beam operation has demonstrated that the ion source is capable of continuous operation for approximately 1100 h. The spark rate at the beam extractor was observed to be at a frequency of less than once a day, which is an acceptable level for user operation. Although an antenna failure occurred during operation on October 26, 2014, no subsequent serious issues have occurred since then. PMID:26932020

  8. RF Driven Multicusp H- Ion Source

    SciTech Connect

    Leung, K.N.; DeVries, G.J.; DiVergilio, W.F.; Hamm, R.W.; Hauck, C.A.; Kunkel, W.B.; McDonald, D.S.; Williams, M.D.

    1990-06-01

    An rf driven multicusp source capable of generating 1-ms H{sup -} beam pulses with a repetition rate as high as 150 Hz has been developed. This source can be operated with a filament or other types of starter. There is almost no lifetime limitation and a clean plasma can be maintained for a long period of operation. It is demonstrated that rf power as high as 25 kW could be coupled inductively to the plasma via a glass-coated copper-coil antenna. The extracted H{sup -} current density achieved is about 200 mA/cm{sup 2}.

  9. Negative hydrogen ion production mechanisms

    SciTech Connect

    Bacal, M.; Wada, M.

    2015-06-15

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  10. Studies on the Extraction Region of the Type VI RF Driven H- Ion Source

    NASA Astrophysics Data System (ADS)

    McNeely, P.; Bandyopadhyay, M.; Franzen, P.; Heinemann, B.; Hu, C.; Kraus, W.; Riedl, R.; Speth, E.; Wilhelm, R.

    2002-11-01

    IPP Garching has spent several years developing a RF driven H- ion source intended to be an alternative to the current ITER (International Thermonuclear Experimental Reactor) reference design ion source. A RF driven source offers a number of advantages to ITER in terms of reduced costs and maintenance requirements. Although the RF driven ion source has shown itself to be competitive with a standard arc filament ion source for positive ions many questions still remain on the physics behind the production of the H- ion beam extracted from the source. With the improvements that have been implemented to the BATMAN (Bavarian Test Machine for Negative Ions) facility over the last two years it is now possible to study both the extracted ion beam and the plasma in the vicinity of the extraction grid in greater detail. This paper will show the effect of changing the extraction and acceleration voltage on both the current and shape of the beam as measured on the calorimeter some 1.5 m downstream from the source. The extraction voltage required to operate in the plasma limit is 3 kV. The perveance optimum for the extraction system was determined to be 2.2 x 10-6 A/V3/2 and occurs at 2.7 kV extraction voltage. The horizontal and vertical beam half widths vary as a function of the extracted ion current and the horizontal half width is generally smaller than the vertical. The effect of reducing the co-extracted electron current via plasma grid biasing on the H- current extractable and the beam profile from the source is shown. It is possible in the case of a silver contaminated plasma to reduce the co-extracted electron current to 20% of the initial value by applying a bias of 12 V. In the case where argon is present in the plasma, biasing is observed to have minimal effect on the beam half width but in a pure hydrogen plasma the beam half width increases as the bias voltage increases. New Langmuir probe studies that have been carried out parallel to the plasma grid (in the

  11. Negative-hydrogen-ion sources

    SciTech Connect

    Prelec, K.

    1983-01-01

    There are two main areas of negative hydrogen ion applications: injection into high energy accelerators and production of beams of energetic hydrogen atoms for fusion devices. In both cases, the ease with which the charge state of negative ions can be changed by either single or double electron stripping is the reason that made their application attractive. In tandem accelerators, the final energy of H/sup +/ ions is twice as high as it would correspond to the terminal voltage, in circular accelerators (synchrotrons, storage rings) injection of H/sup +/ ions by full stripping of H/sup -/ ions in a foil inside the ring is not limited by the Liouville's theorem and results in a higher phase space density than achieved by direct H/sup +/ injection. Finally, beams of hydrogen atoms at energies above 100 keV, which will be required for plasma heating and current drive in future fusion devices, can efficiently be produced only by acceleration of negative ions and their subsequent neutralization.

  12. Size scaling of negative hydrogen ion sources for fusion

    NASA Astrophysics Data System (ADS)

    Fantz, U.; Franzen, P.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.

    2015-04-01

    The RF-driven negative hydrogen ion source (H-, D-) for the international fusion experiment ITER has a width of 0.9 m and a height of 1.9 m and is based on a ⅛ scale prototype source being in operation at the IPP test facilities BATMAN and MANITU for many years. Among the challenges to meet the required parameters in a caesiated source at a source pressure of 0.3 Pa or less is the challenge in size scaling of a factor of eight. As an intermediate step a ½ scale ITER source went into operation at the IPP test facility ELISE with the first plasma in February 2013. The experience and results gained so far at ELISE allowed a size scaling study from the prototype source towards the ITER relevant size at ELISE, in which operational issues, physical aspects and the source performance is addressed, highlighting differences as well as similarities. The most ITER relevant results are: low pressure operation down to 0.2 Pa is possible without problems; the magnetic filter field created by a current in the plasma grid is sufficient to reduce the electron temperature below the target value of 1 eV and to reduce together with the bias applied between the differently shaped bias plate and the plasma grid the amount of co-extracted electrons. An asymmetry of the co-extracted electron currents in the two grid segments is measured, varying strongly with filter field and bias. Contrary to the prototype source, a dedicated plasma drift in vertical direction is not observed. As in the prototype source, the performance in deuterium is limited by the amount of co-extracted electrons in short as well as in long pulse operation. Caesium conditioning is much harder in deuterium than in hydrogen for which fast and reproducible conditioning is achieved. First estimates reveal a caesium consumption comparable to the one in the prototype source despite the large size.

  13. rf driven multicusp H sup minus ion source

    SciTech Connect

    Leung, K.N.; DeVries, G.J.; DiVergilio, W.F.; Hamm, R.W.; Hauck, C.A.; Kunkel, W.B.; McDonald, D.S.; Williams, M.D. )

    1991-01-01

    An rf driven multicusp source capable of generating 1-ms H{sup {minus}} beam pulses with a repetition rate as high as 150 Hz has been developed. This source can be operated with a filament or other types of starter. There is almost no lifetime limitation and a clean plasma can be maintained for a long period of operation. It is demonstrated that rf power as high as 25 kW could be coupled inductively to the plasma via a glass-coated copper-coil antenna. The extracted H{sup {minus}} current density achieved is about 200 mA/cm{sup 2}.

  14. Tunable negative Poisson's ratio in hydrogenated graphene.

    PubMed

    Jiang, Jin-Wu; Chang, Tienchong; Guo, Xingming

    2016-09-21

    We perform molecular dynamics simulations to investigate the effect of hydrogenation on the Poisson's ratio of graphene. It is found that the value of the Poisson's ratio of graphene can be effectively tuned from positive to negative by varying the percentage of hydrogenation. Specifically, the Poisson's ratio decreases with an increase in the percentage of hydrogenation, and reaches a minimum value of -0.04 when the percentage of hydrogenation is about 50%. The Poisson's ratio starts to increase upon a further increase of the percentage of hydrogenation. The appearance of a minimum negative Poisson's ratio in the hydrogenated graphene is attributed to the suppression of the hydrogenation-induced ripples during the stretching of graphene. Our results demonstrate that hydrogenation is a valuable approach for tuning the Poisson's ratio from positive to negative in graphene. PMID:27536878

  15. Size scaling of negative hydrogen ion sources for fusion

    SciTech Connect

    Fantz, U. Franzen, P.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.

    2015-04-08

    The RF-driven negative hydrogen ion source (H{sup −}, D{sup −}) for the international fusion experiment ITER has a width of 0.9 m and a height of 1.9 m and is based on a ⅛ scale prototype source being in operation at the IPP test facilities BATMAN and MANITU for many years. Among the challenges to meet the required parameters in a caesiated source at a source pressure of 0.3 Pa or less is the challenge in size scaling of a factor of eight. As an intermediate step a ½ scale ITER source went into operation at the IPP test facility ELISE with the first plasma in February 2013. The experience and results gained so far at ELISE allowed a size scaling study from the prototype source towards the ITER relevant size at ELISE, in which operational issues, physical aspects and the source performance is addressed, highlighting differences as well as similarities. The most ITER relevant results are: low pressure operation down to 0.2 Pa is possible without problems; the magnetic filter field created by a current in the plasma grid is sufficient to reduce the electron temperature below the target value of 1 eV and to reduce together with the bias applied between the differently shaped bias plate and the plasma grid the amount of co-extracted electrons. An asymmetry of the co-extracted electron currents in the two grid segments is measured, varying strongly with filter field and bias. Contrary to the prototype source, a dedicated plasma drift in vertical direction is not observed. As in the prototype source, the performance in deuterium is limited by the amount of co-extracted electrons in short as well as in long pulse operation. Caesium conditioning is much harder in deuterium than in hydrogen for which fast and reproducible conditioning is achieved. First estimates reveal a caesium consumption comparable to the one in the prototype source despite the large size.

  16. Low pressure and high power rf sources for negative hydrogen ions for fusion applications (ITER neutral beam injection).

    PubMed

    Fantz, U; Franzen, P; Kraus, W; Falter, H D; Berger, M; Christ-Koch, S; Fröschle, M; Gutser, R; Heinemann, B; Martens, C; McNeely, P; Riedl, R; Speth, E; Wünderlich, D

    2008-02-01

    The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D(-) for up to 1 h with an accelerated current density of 200 Am/(2) and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m(2) from an aperture array with an envelope of 1.5 x 0.6 m(2). A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP) at three test facilities in parallel. Current densities of 330 and 230 Am/(2) have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m(2)) and short pulses (<4 s). In the long pulse experiment, equipped with an extraction area of 0.02 m(2), the pulse length has been extended to 3600 s. A large rf source, with the width and half the height of the ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.

  17. An advanced negative hydrogen ion source.

    PubMed

    Goncharov, Alexey A; Dobrovolsky, Andrey N; Goretskii, Victor P

    2016-02-01

    The results of investigation of emission productivity of negative particles source with cesiated combined discharge are presented. A cylindrical beam of negative hydrogen ions with density about 2 A/cm(2) in low noise mode on source emission aperture is obtained. The total beam current values are up to 200 mA for negative hydrogen ions and up to 1.5 A for all negative particles with high divergence after source. The source has simple design and can produce stable discharge with low level of oscillation. PMID:26931996

  18. Negative hydrogen ion yields at plasma grid surface in a negative hydrogen ion source

    SciTech Connect

    Wada, M.; Kenmotsu, T.; Sasao, M.

    2015-04-08

    Negative hydrogen (H{sup −}) ion yield from the plasma grid due to incident hydrogen ions and neutrals has been evaluated with the surface collision cascade model, ACAT (Atomic Collision in Amorphous Target) coupled to a negative surface ionization models. Dependence of negative ion fractions upon the velocity component normal to the surface largely affect the calculation results of the final energy and angular distributions of the H{sup −} ions. The influence is particularly large for H{sup −} ions desorbed from the surface due to less than several eV hydrogen particle implact. The present calculation predicts that H{sup −} ion yield can be maximized by setting the incident angle of hydrogen ions and neutrals to be 65 degree. The Cs thickness on the plasma grid should also affect the yields and mean energies of surface produced H{sup −} ions by back scattering and ion induced desorption processes.

  19. Compression effects in inductively coupled, high-power radio-frequency discharges for negative hydrogen ion production

    NASA Astrophysics Data System (ADS)

    Wilhelm, Rolf

    2003-02-01

    In the paper we present a simplified model description of inductively coupled plasma discharges operating at a rather high radio-frequency (rf) power. In this case the induced high plasma currents can cause periodic compressions over a substantial radial distance. Such conditions are obviously given in rf driven 1 MHz/150 kW plasma sources developed at the Institute for Plasma Physics Garching for negative (hydrogen) ion production in future neutral beam injection (NBI) systems for nuclear fusion research, such as the 1 MeV/50 MW NBI system for the International Thermonuclear Experimental Reactor [T. Inoue, R. Hemsworth, V. Kulygin, and Y. Okumura, Fusion Eng. Design 55, 291 (2001)]. The given model describes quite well the compression and other features of the discharge. The results include the Ohmic power input (i.e., electron heating), the resulting density build-up, and—as a new feature—periodical plasma compressions, leading to a direct energy input also into the plasma ions. The model also explains the strange effect of small argon admixtures, which improve the negative ion yield in rf sources by a factor of up to 2-3 (but which have no effect in conventional dc arc sources). With the calculated dependencies from external parameters (e.g., rf-power and frequency, gas pressure, ion mass or the specific geometry), the modeling may help for the further optimization of the rf source.

  20. Negative ion extraction from hydrogen plasma bulk

    SciTech Connect

    Oudini, N.; Taccogna, F.; Minelli, P.

    2013-10-15

    A two-dimensional particle-in-cell/Monte Carlo collision model has been developed and used to study low electronegative magnetized hydrogen plasma. A configuration characterized by four electrodes is used: the left electrode is biased at V{sub l} = −100 V, the right electrode is grounded, while the upper and lower transversal electrodes are biased at an intermediate voltage V{sub ud} between 0 and −100 V. A constant and homogeneous magnetic field is applied parallel to the lateral (left/right) electrodes. It is shown that in the magnetized case, the bulk plasma potential is close to the transversal electrodes bias inducing then a reversed sheath in front of the right electrode. The potential drop within the reversed sheath is controlled by the transversal electrodes bias allowing extraction of negative ions with a significant reduction of co-extracted electron current. Furthermore, introducing plasma electrodes, between the transversal electrodes and the right electrode, biased with a voltage just above the plasma bulk potential, increases the negative ion extracted current and decreases significantly the co-extracted electron current. The physical mechanism on basis of this phenomenon has been discussed.

  1. Production of negative hydrogen ions on metal grids

    SciTech Connect

    Oohara, W.; Maetani, Y.; Takeda, Takashi; Takeda, Toshiaki; Yokoyama, H.; Kawata, K.

    2015-03-15

    Negative hydrogen ions are produced on a nickel grid with positive-ion irradiation. In order to investigate the production mechanism, a copper grid without the chemisorption of hydrogen atoms and positive helium ions without negative ionization are used for comparison. Positive hydrogen ions reflected on the metal surface obtain two electrons from the surface and become negatively ionized. It is found that the production yield of negative ions by desorption ionization of chemisorbed hydrogen atoms seems to be small, and the production is a minor mechanism.

  2. Production of negative hydrogen ions on metal grids

    NASA Astrophysics Data System (ADS)

    Oohara, W.; Maetani, Y.; Takeda, Takashi; Takeda, Toshiaki; Yokoyama, H.; Kawata, K.

    2015-03-01

    Negative hydrogen ions are produced on a nickel grid with positive-ion irradiation. In order to investigate the production mechanism, a copper grid without the chemisorption of hydrogen atoms and positive helium ions without negative ionization are used for comparison. Positive hydrogen ions reflected on the metal surface obtain two electrons from the surface and become negatively ionized. It is found that the production yield of negative ions by desorption ionization of chemisorbed hydrogen atoms seems to be small, and the production is a minor mechanism.

  3. Investigation of fringe plasma parameters on a high power rf driven ion source

    SciTech Connect

    McNeely, P.; Schiesko, L.

    2010-02-15

    It has been observed that there are differences between the uncompensated Langmuir probes installed in the upper and lower areas of the rf driven H{sup -} sources at IPP Garching. The two probes often had substantially different floating potentials or ion saturation currents. In an effort to understand the reasons for these differences a Langmuir probe analysis system was used on the probes to collect the full current voltage characteristic. The results show what is likely the formation of an ion-ion plasma. The paper shows the effect of beam extraction and the presence of caesium on the probe characteristics.

  4. Approximate Integrals of rf-driven Particle Motion in Magnetic Field

    SciTech Connect

    I.Y. Dodin; N.J. Fisch

    2004-04-26

    For a particle moving in nonuniform magnetic field under the action of an rf wave, ponderomotive effects result from rf-driven oscillations nonlinearly coupled with Larmor rotation. Using Lagrangian and Hamiltonian formalism, we show how, despite this coupling, two independent integrals of the particle motion are approximately conserved. Those are the magnetic moment of free Larmor rotation and the quasi-energy of the guiding center motion parallel to the magnetic field. Under the assumption of non-resonant interaction of the particle with the rf field, these integrals represent adiabatic invariants of the particle motion.

  5. Study on space charge compensation in negative hydrogen ion beam.

    PubMed

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    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(+) 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(-) beam from a 2.45 GHz microwave driven H(-) 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. PMID:26932087

  6. Study on space charge compensation in negative hydrogen ion beam.

    PubMed

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    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(+) 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(-) beam from a 2.45 GHz microwave driven H(-) 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.

  7. Electron Transport across Magnetic Filter in Negative Hydrogen Ion Source

    NASA Astrophysics Data System (ADS)

    Fukano, Azusa; Ogasawara, Masatada

    2001-12-01

    Profiles of electron temperature and number density in a negative-ion source are investigated theoretically. Spatial dependence over the magnetic filter region is obtained using the equations of electron flux and electron heat flux that include the effect of interference of forces by the density gradient and temperature gradient. Due to the effect of the magnetic filter, temperature and density of the electron decrease from the source chamber to the extraction chamber, and the decrease depends on the magnitude of the magnetic flux. The effect of the magnetic filter on the production and destruction rates of the negative hydrogen ion is examined. The reaction rate for the dissociative attachment reaction which produces the negative hydrogen ion increases with the decrease of the electron temperature. However, the production rate per one vibrationally excited hydrogen molecule decreases with the decrease of electron density. On the other hand, the destruction probability of the negative ion by the electron detachment reaction decreases significantly by the decrease of the electron density and temperature. The magnetic filter does not enhance the production of the negative hydrogen ion, but it reduces the destruction of the negative ion because of the decrease of the electron density.

  8. Fine-tuning to minimize emittances of J-PARC RF-driven H- ion source

    NASA Astrophysics Data System (ADS)

    Ueno, A.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Oguri, H.

    2016-02-01

    The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H- ion source has been successfully operated for about one year. By the world's brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity.

  9. Deactivating bacteria with RF Driven Hollow Slot Microplasmas in Open Air at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Yu, Zengqi; Pruden, Amy; Sharma, Ashish; Collins, George

    2003-10-01

    A hollow slot discharge operating in open air at atmospheric pressure has demonstrated its ability to deactivate bacterial growth on nearby surfaces exposed to the RF driven plasma. The cold plasma exits from a hollow slot with a width of 0.2 mm and variable length of 1-35 cm. An internal electrode was powered by 13.56 MHz radio-frequency power at a voltage below 200 V. External electrically grounded slots face the work piece. The plasma plume extends millimeters to centimeter beyond the hollow slot toward the work piece to be irradiated. Argon-Oxygen gas mixtures, at 33 liters per minute flow, were passed through the electrodes and the downstream plasma was employed for the process, with treatment exposure time varied from 0.06 to 0.18 seconds. Bacterial cultures were fixed to 0.22 micron cellulose filter membranes and passed under the plasma at a controlled rate at a distance of about 5-10 millimeters from the grounded slot electrode. Preliminary studies on the effectiveness of the plasma for sterilization were carried out on E. coli. Cultures were grown overnight on the membranes after exposure and the resulting colony forming units (cfu) were determined in treated and untreated groups. In the plasma treated group, a 98.2% kill rate was observed with the lowest exposure time, and increased to 99.8% when the exposure time was tripled. These studies clearly demonstrate the ability of the RF-driven hollow slot atmospheric plasma to inhibit bacterial growth on surfaces.

  10. Negative ion yields in hydrogen scattering from graphite surfaces

    SciTech Connect

    Gleeson, M. A.; Koppers, W. R.; Kleyn, A. W.; Tsumori, K.

    1998-08-20

    We compare the negative ion fraction obtained for scattering of hydrogenous ions (H{sub x}{sup +}, x=1-3) from highly oriented pyrolytic graphite (HOPG), with that obtained for scattering from a polycrystalline graphite surface. In contrast to the HOPG surface, which has a negative ion yield of the order of 1-2%, the polycrystalline sample has yields of up to 30%.

  11. Linac4 low energy beam measurements with negative hydrogen ions

    NASA Astrophysics Data System (ADS)

    Scrivens, R.; Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T.

    2014-02-01

    Linac4, a 160 MeV normal-conducting H- linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H- beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  12. Linac4 low energy beam measurements with negative hydrogen ions

    SciTech Connect

    Scrivens, R. Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T.

    2014-02-15

    Linac4, a 160 MeV normal-conducting H{sup −} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup −} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  13. Linac4 low energy beam measurements with negative hydrogen ions.

    PubMed

    Scrivens, R; Bellodi, G; Crettiez, O; Dimov, V; Gerard, D; Granemann Souza, E; Guida, R; Hansen, J; Lallement, J-B; Lettry, J; Lombardi, A; Midttun, Ø; Pasquino, C; Raich, U; Riffaud, B; Roncarolo, F; Valerio-Lizarraga, C A; Wallner, J; Yarmohammadi Satri, M; Zickler, T

    2014-02-01

    Linac4, a 160 MeV normal-conducting H(-) linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H(-) beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

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

    DOEpatents

    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

  15. A new hybrid scheme for simulations of highly collisional RF-driven plasmas

    NASA Astrophysics Data System (ADS)

    Eremin, Denis; Hemke, Torben; Mussenbrock, Thomas

    2016-02-01

    This work describes a new 1D hybrid approach for modeling atmospheric pressure discharges featuring complex chemistry. In this approach electrons are described fully kinetically using particle-in-cell/Monte-Carlo (PIC/MCC) scheme, whereas the heavy species are modeled within a fluid description. Validity of the popular drift-diffusion approximation is verified against a ‘full’ fluid model accounting for the ion inertia and a fully kinetic PIC/MCC code for ions as well as electrons. The fluid models require knowledge of the momentum exchange frequency and dependence of the ion mobilities on the electric field when the ions are in equilibrium with the latter. To this end an auxiliary Monte-Carlo scheme is constructed. It is demonstrated that the drift-diffusion approximation can overestimate ion transport in simulations of RF-driven discharges with heavy ion species operated in the γ mode at the atmospheric pressure or in all discharge simulations for lower pressures. This can lead to exaggerated plasma densities and incorrect profiles provided by the drift-diffusion models. Therefore, the hybrid code version featuring the full ion fluid model should be favored against the more popular drift-diffusion model, noting that the suggested numerical scheme for the former model implies only a small additional computational cost.

  16. Negative hydrogen ion source for TOKAMAK neutral beam injector (invited)

    NASA Astrophysics Data System (ADS)

    Okumura, Y.; Fujiwara, Y.; Kashiwagi, M.; Kitagawa, T.; Miyamoto, K.; Morishita, T.; Hanada, M.; Takayanagi, T.; Taniguchi, M.; Watanabe, K.

    2000-02-01

    Intense negative ion source producing multimegawatt hydrogen/deuterium negative ion beams has been developed for the neutral beam injector (NBI) in TOKAMAK thermonuclear fusion machines. Negative ions are produced in a cesium seeded multi-cusp plasma generator via volume and surface processes, and accelerated with a multistage electrostatic accelerator. The negative ion source for JT-60U has produced 18.5 A/360 keV (6.7 MW) H- and 14.3 A/380 keV (5.4 MW) D- ion beams at average current densities of 11 mA/cm2 (H-) and 8.5 mA/cm2 (D-). A high energy negative ion source has been developed for the next generation TOKAMAK such as the International Thermonuclear Experimental Reactor (ITER). The source has demonstrated to accelerate negative ions up to 1 MeV, the energy required for ITER. Higher negative ion current density of more than 20 mA/cm2 was obtained in the ITER concept sources. It was confirmed that the consumption rate of cesium is small enough to operate the source for a half year in ITER-NBI without maintenance.

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

    SciTech Connect

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

    2015-04-08

    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. Negative hydrogen ion production in a helicon plasma source

    SciTech Connect

    Santoso, J. Corr, C. S.; Manoharan, R.; O'Byrne, S.

    2015-09-15

    In order to develop very high energy (>1 MeV) neutral beam injection systems for applications, such as plasma heating in fusion devices, it is necessary first to develop high throughput negative ion sources. For the ITER reference source, this will be realised using caesiated inductively coupled plasma devices, containing either hydrogen or deuterium discharges, operated with high rf input powers (up to 90 kW per driver). It has been suggested that due to their high power coupling efficiency, helicon devices may be able to reduce power requirements and potentially obviate the need for caesiation due to the high plasma densities achievable. Here, we present measurements of negative ion densities in a hydrogen discharge produced by a helicon device, with externally applied DC magnetic fields ranging from 0 to 8.5 mT at 5 and 10 mTorr fill pressures. These measurements were taken in the magnetised plasma interaction experiment at the Australian National University and were performed using the probe-based laser photodetachment technique, modified for the use in the afterglow of the plasma discharge. A peak in the electron density is observed at ∼3 mT and is correlated with changes in the rf power transfer efficiency. With increasing magnetic field, an increase in the negative ion fraction from 0.04 to 0.10 and negative ion densities from 8 × 10{sup 14 }m{sup −3} to 7 × 10{sup 15 }m{sup −3} is observed. It is also shown that the negative ion densities can be increased by a factor of 8 with the application of an external DC magnetic field.

  19. A future, intense source of negative hydrogen ions

    NASA Technical Reports Server (NTRS)

    Siefken, Hugh; Stein, Charles

    1994-01-01

    By directly heating lithium hydride in a vacuum, up to 18 micro-A/sq cm of negative hydrogen has been obtained from the crystal lattice. The amount of ion current extracted and analyzed is closely related to the temperature of the sample and to the rate at which the temperature is changed. The ion current appears to be emission limited and saturates with extraction voltage. For a fixed extraction voltage, the ion current could be maximized by placing a grid between the sample surface and the extraction electrode. Electrons accompanying the negative ions were removed by a magnetic trap. A Wein velocity filter was designed and built to provide definitive mass analysis of the extracted ion species. This technique when applied to other alkali hydrides may produce even higher intensity beams possessing low values of emittance.

  20. Development of a novel radio-frequency negative hydrogen ion source in conically converging configuration.

    PubMed

    Jung, B K; Dang, J J; An, Y H; Chung, K J; Hwang, Y S

    2014-02-01

    Volume-produced negative ion source still requires enhancement of current density with lower input RF (radio-frequency) power in lower operating pressure for various applications. To confirm recent observation of efficient negative ion production with a short cylindrical chamber with smaller effective plasma size, the RF-driven transformer-coupled plasma H(-) ion source at Seoul National University is modified by adopting a newly designed quartz RF window to reduce the chamber length. Experiments with the reduced chamber length show a few times enhancement of H(-) ion beam current compared to that extracted from the previous chamber design, which is consistent with the measured H(-) ion population. Nevertheless, decrease in H(-) ion beam current observed in low pressure regime below ∼5 mTorr owing to insufficient filtering of high energy electrons in the extraction region needs to be resolved to address the usefulness of electron temperature control by the change of geometrical configuration of the discharge chamber. A new discharge chamber with conically converging configuration has been developed, in which the chamber diameter decreases as approaching to the extraction region away from the planar RF antenna such that stronger filter magnetic field can be utilized to prohibit high energy electrons from transporting to the extraction region. First experimental results for the H(-) ion beam extraction with this configuration show that higher magnetic filter field makes peak negative beam currents happen in lower operating pressure. However, overall decrease in H(-) ion beam current due to the change of chamber geometry still requires further study of geometrical effect on particle transport and optimization of magnetic field in this novel configuration.

  1. Experimental studies of the Negative Ion of Hydrogen. Final Report

    SciTech Connect

    Bryant, Howard C.

    1999-06-30

    This document presents an overview of the results of the DOE'S support of experimental research into the structure and interactions of the negative ion of hydrogen conducted by the Department of Physics and Astronomy of the University of New Mexico at the Los Alamos National Laboratory. The work involves many collaborations with scientists from both institutions, as well as others. Although official DOE support for this work began in 1977, the experiment that led to it was done in 1971, near the time the 800 MeV linear accelerator at Los Alamos (LAMPF) first came on line. Until the mid nineties, the work was performed using the relativistic beam at LAMFF. The most recent results were obtained using the 35 keV injector beam for the Ground Test Accelerator at Los Alamos. A list of all published results from this work is presented.

  2. Cavity Ring-Down System for Density Measurement of Negative Hydrogen Ion on Negative Ion Source

    SciTech Connect

    Nakano, Haruhisa; Tsumori, Katsuyoshi; Nagaoka, Kenichi; Shibuya, Masayuki; Kisaki, Masashi; Ikeda, Katsunori; Osakabe, Masaki; Kaneko, Osamu; Asano, Eiji; Kondo, Tomoki; Sato, Mamoru; Komada, Seiji; Sekiguchi, Haruo; Takeiri, Yasuhiko; Fantz, Ursel

    2011-09-26

    A Cavity Ring-Down (CRD) system was applied to measure the density of negative hydrogen ion (H{sup -}) in vicinity of extraction surface in the H{sup -} source for the development of neutral beam injector on Large Helical Device (LHD). The density measurement with sampling time of 50 ms was carried out. The measured density with the CRD system is relatively good agreement with the density evaluated from extracted beam-current with applying a similar relation of positive ion sources. In cesium seeded into ion-source plasma, the linearity between an arc power of the discharge and the measured density with the CRD system was observed. Additionally, the measured density was proportional to the extracted beam current. These characteristics indicate the CRD system worked well for H{sup -} density measurement in the region of H{sup -} and extraction.

  3. Rod-filter-field optimization of the J-PARC RF-driven H{sup −} ion source

    SciTech Connect

    Ueno, A. Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

    2015-04-08

    In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second-stage requirements of an H{sup −} ion beam of 60mA within normalized emittances of 1.5πmm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H{sup −} ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). Although rod-filter-field (RFF) is indispensable and one of the most beam performance dominative parameters for the RF-driven H{sup −} ion source with the internal-antenna, the procedure to optimize it is not established. In order to optimize the RFF and establish the procedure, the beam performances of the J-PARC source with various types of rod-filter-magnets (RFMs) were measured. By changing RFM’s gap length and gap number inside of the region projecting the antenna inner-diameter along the beam axis, the dependence of the H{sup −} ion beam intensity on the net 2MHz-RF power was optimized. Furthermore, the fine-tuning of RFM’s cross-section (magnetmotive force) was indispensable for easy operation with the temperature (T{sub PE}) of the plasma electrode (PE) lower than 70°C, which minimizes the transverse emittances. The 5% reduction of RFM’s cross-section decreased the time-constant to recover the cesium effects after an slightly excessive cesiation on the PE from several 10 minutes to several minutes for T{sub PE} around 60°C.

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

    DOEpatents

    Hershcovitch, Ady

    1987-01-01

    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 intersected by a beam of laser light. Photodetachment is effected in a uniform magnetic field that is provided around the beam of H.sup.- ions to spin polarize the H.sup.- ions and produce first and second populations or groups of ions, having their respective proton spin aligned either with the magnetic field or opposite to it. The intersecting beam of laser light is directed to selectively neutralize a majority of the ions in only one population, or given spin polarized group of H.sup.- ions, without neutralizing the ions in the other group thereby forming a population of H.sup.- ions each of which has its proton spin down, and a second group or population of H.sup.o atoms having proton spin up. Finally, the two groups of ions are separated from each other by magnetically bending the group of H.sup.- ions away from the group of neutralized ions, thereby to form an intense H.sup.- ion beam that is directed toward a predetermined objective.

  5. Contribution of wall material to the vibrational excitation and negative ion formation in hydrogen negative ion sources (invited)

    NASA Astrophysics Data System (ADS)

    Bacal, M.; Ivanov, A. A.; Glass-Maujean, M.; Matsumoto, Y.; Nishiura, M.; Sasao, M.; Wada, M.

    2004-05-01

    The wall production contribution to the negative hydrogen ion formation in multicusp ion sources has been investigated using the photodetachment diagnostic (for determining the negative ion density and temperature), negative ion and electron extraction, and vacuum ultraviolet (VUV) emission spectroscopy. The wall material was modified either by depositing thin films from filaments made of different material or by depositing fresh material of the same filament. Thus we show that a fresh tantalum film leads to enhanced negative ion density and enhanced temperature of the hot negative ion population. The slow poisoning effect due to argon additive also indicates the presence of the wall contribution to H- formation. The study of the VUV spectra with different wall materials indicates the presence of vibrationally excited states of H2.

  6. Emittance measurements for optimum operation of the J-PARC RF-driven H{sup −} ion source

    SciTech Connect

    Ueno, A. Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

    2015-04-08

    In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H{sup −} ion beam of 60mA within normalized emittances of 1.5πmm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H{sup −} ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The transverse emittances of the source were measured with various conditions to find out the optimum operation conditions minimizing the horizontal and vertical rms normalized emittances. The transverse emittances were most effectively reduced by operating the source with the plasma electrode temperature lower than 70°C. The optimum value of the cesium (Cs) density around the beam hole of the plasma electrode seems to be proportional to the plasma electrode temperature. The fine control of the Cs density is indispensable, since the emittances seem to increase proportionally to the excessiveness of the Cs density. Furthermore, the source should be operated with the Cs density beyond a threshold value, since the plasma meniscus shape and the ellipse parameters of the transverse emittances seem to be changed step-function-likely on the threshold Cs value.

  7. Laser photodetachment diagnostics of a 1/3-size negative hydrogen ion source for NBI

    SciTech Connect

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

    2015-04-08

    To investigate the flows of charged particles in front of the plasma grid (PG) in a negative hydrogen ion source, the information of the local densities of electrons and negative hydrogen ions (H-) are necessary. For this purpose, the laser photodetachment is applied for pure hydrogen plasmas and Cs-seeded plasma in a 1/3-size negative hydrogen ion source in NIFS-NBI test stand. The H- density obtained by photodetachment is calibrated by the results from cavity ring-down (CRD). The pressure dependence and PG bias dependence of the local H- density are presented and discussed. The results show that H- density increases significantly by seeding Cs into the plasma. In Cs-seeded plasma, relativity exists between the H- ion density and plasma potential.

  8. Design and Start-to-End Simulation of an X-Band RF Driven Hard X-Ray FEL with LCLS Injector

    SciTech Connect

    Sun, Yipeng; /SLAC

    2012-08-20

    In this note, it is briefly discussed the accelerator design and start-to-end 3D macro particles simulation (using ELEGANT and GENESIS) of an X-band RF driven hard X-ray FEL with LCLS injector. A preliminary design and LiTrack 1D simulation studies were presented before in an older publication [1]. In numerical simulations this X-band RF driven hard X-ray FEL achieves/exceeds LCLS-like performance in a much shorter overall length of 350 m, compared with 1200 m in the LCLS case. One key feature of this design is that it may achieve a higher final beam current of 5 kA plus a uniform energy profile, mainly due to the employment of stronger longitudinal wake fields in the last X-band RF linac [2].

  9. A large-area RF source for negative hydrogen ions

    NASA Astrophysics Data System (ADS)

    Frank, P.; Feist, J. H.; Kraus, W.; Speth, E.; Heinemann, B.; Probst, F.; Trainham, R.; Jacquot, C.

    1998-08-01

    In a collaboration with CEA Cadarache, IPP is presently developing an rf source, in which the production of negative ions (H-/D-) is being investigated. It utilizes PINI-size rf sources with an external antenna and for the first step a small size extraction system with 48 cm2 net extraction area. First results from BATMAN (Ba¯varian T_est Ma¯chine for N_egative Ions) show (without Cs) a linear dependence of the negative ion yield with rf power, without any sign of saturation. At elevated pressure (1.6 Pa) a current density of 4.5 mA/cm2 H- (without Cs) has been found so far. At medium pressure (0.6 Pa) the current density is lower by approx. a factor of 5, but preliminary results with Cesium injection show a relative increase by almost the same factor in this pressure range. Langmuir probe measurements indicate an electron temperature Te>2 eV close to the plasma grid with a moderate magnetic filter (700 Gcm). Attempts to improve the performance by using different magnetic configurations and different wall materials are under way.

  10. Effects of discharge chamber length on the negative ion generation in volume-produced negative hydrogen ion source

    SciTech Connect

    Chung, Kyoung-Jae; Jung, Bong-Ki; An, YoungHwa; Dang, Jeong-Jeung; Hwang, Y. S.

    2014-02-15

    In a volume-produced negative hydrogen ion source, control of electron temperature is essential due to its close correlation with the generation of highly vibrationally excited hydrogen molecules in the heating region as well as the generation of negative hydrogen ions by dissociative attachment in the extraction region. In this study, geometric effects of the cylindrical discharge chamber on negative ion generation via electron temperature changes are investigated in two discharge chambers with different lengths of 7.5 cm and 11 cm. Measurements with a radio-frequency-compensated Langmuir probe show that the electron temperature in the heating region is significantly increased by reducing the length of the discharge chamber due to the reduced effective plasma size. A particle balance model which is modified to consider the effects of discharge chamber configuration on the plasma parameters explains the variation of the electron temperature with the chamber geometry and gas pressure quite well. Accordingly, H{sup −} ion density measurement with laser photo-detachment in the short chamber shows a few times increase compared to the longer one at the same heating power depending on gas pressure. However, the increase drops significantly as operating gas pressure decreases, indicating increased electron temperatures in the extraction region degrade dissociative attachment significantly especially in the low pressure regime. It is concluded that the increase of electron temperature by adjusting the discharge chamber geometry is efficient to increase H{sup −} ion production as long as low electron temperatures are maintained in the extraction region in volume-produced negative hydrogen ion sources.

  11. A large-area RF source for negative hydrogen ions

    SciTech Connect

    Frank, P.; Feist, J. H.; Kraus, W.; Speth, E.; Heinemann, B.; Probst, F.; Trainham, R.; Jacquot, C.

    1998-08-20

    In a collaboration with CEA Cadarache, IPP is presently developing an rf source, in which the production of negative ions (H{sup -}/D{sup -}) is being investigated. It utilizes PINI-size rf sources with an external antenna and for the first step a small size extraction system with 48 cm{sup 2} net extraction area. First results from BATMAN (Bavarian T lowbar est Machine for N lowbar egative Ions) show (without Cs) a linear dependence of the negative ion yield with rf power, without any sign of saturation. At elevated pressure (1.6 Pa) a current density of 4.5 mA/cm{sup 2} H{sup -} (without Cs) has been found so far. At medium pressure (0.6 Pa) the current density is lower by approx. a factor of 5, but preliminary results with Cesium injection show a relative increase by almost the same factor in this pressure range. Langmuir probe measurements indicate an electron temperature T{sub e}>2 eV close to the plasma grid with a moderate magnetic filter (700 Gcm). Attempts to improve the performance by using different magnetic configurations and different wall materials are under way.

  12. Optimum plasma grid bias for a negative hydrogen ion source operation with Cs

    NASA Astrophysics Data System (ADS)

    Bacal, Marthe; Sasao, Mamiko; Wada, Motoi; McAdams, Roy

    2016-02-01

    The functions of a biased plasma grid of a negative hydrogen (H-) ion source for both pure volume and Cs seeded operations are reexamined. Proper control of the plasma grid bias in pure volume sources yields: enhancement of the extracted negative ion current, reduction of the co-extracted electron current, flattening of the spatial distribution of plasma potential across the filter magnetic field, change in recycling from hydrogen atomic/molecular ions to atomic/molecular neutrals, and enhanced concentration of H- ions near the plasma grid. These functions are maintained in the sources seeded with Cs with additional direct emission of negative ions under positive ion and neutral hydrogen bombardment onto the plasma electrode.

  13. Production of negative hydrogen and deuterium ions in microwave-driven ion sources.

    SciTech Connect

    Spence, D.

    1998-09-11

    The authors report progress they have made in the production of negative hydrogen and deuterium atomic ions in magnetically-confined microwave-driven (2.45 GHz) ion sources. The influence of source surface material, microwave power, source gas pressure and magnetic field configuration on the resulting ion current is discussed. Results strongly suggest that, at least in the source, vibrationally excited molecular hydrogen, the precursor to atomic negative ion production, is produced via a surface mechanism suggested by Hall et al. rather than via a gas phase reaction as is generally believed to be the case in most ion sources.

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

    SciTech Connect

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

    2013-12-16

    We present observations of intense beams of energetic negative hydrogen ions and fast neutral hydrogen atoms in intense (5 × 10{sup 19} W/cm{sup 2}) laser plasma interaction experiments, which were quantified in numerical calculations. Generation of negative ions and neutral atoms is ascribed to the processes of electron capture and loss by a laser accelerated positive ion in the collisions with a cloud of droplets. A comparison with a numerical model of charge exchange processes provides information on the cross section of the electron capture in the high energy domain.

  15. Effect of nickel grid parameters on production of negative hydrogen ions

    SciTech Connect

    Oohara, W.; Yokoyama, H.; Takeda, Toshiaki; Maetani, Y.; Takeda, Takashi; Kawata, K.

    2014-06-15

    Negative hydrogen ions are produced by plasma-assisted catalytic ionization using a nickel grid. When positive ions passing through the grid are decelerated by an electric field, the extraction current density of passing positive ions is sharply reduced by neutralization and negative ionization of the ions. This phenomenon is found to depend on the specific surface area of the grid and the current density.

  16. Roles of a plasma grid in a negative hydrogen ion source

    SciTech Connect

    Bacal, M.; Sasao, M.; Wada, M.; McAdams, R.

    2015-04-08

    The plasma grid is electrically biased with respect to other parts of source chamber wall in both volume sources and sources seeded with alkali metals. The roles of the plasma grid in these two kinds of sources will be described. The main functions of the plasma grid in volume sources are: optimizing the extracted negative ion current, reducing the co-extracted electron current, controlling the axial plasma potential profile, recycling the hydrogen atoms to molecules, concentrating the negative ions near its surface and, when biased positive, depleting the electron population near its surface. These functions are maintained in the sources seeded with alkali metals. However an additional function appears in the Cs seeded sources, namely direct emission of negative ions under positive ion and neutral hydrogen bombardment.

  17. Ways to improve the efficiency and reliability of radio frequency driven negative ion sources for fusion

    SciTech Connect

    Kraus, W.; Briefi, S.; Fantz, U.; Gutmann, P.; Doerfler, J.

    2014-02-15

    Large RF driven negative hydrogen ion sources are being developed at IPP Garching for the future neutral beam injection system of ITER. The overall power efficiency of these sources is low, because for the RF power supply self-excited generators are utilized and the plasma is generated in small cylindrical sources (“drivers”) and expands into the source main volume. At IPP experiments to reduce the primary power and the RF power required for the plasma production are performed in two ways: The oscillator generator of the prototype source has been replaced by a transistorized RF transmitter and two alternative driver concepts, a spiral coil, in which the field is concentrated by ferrites, which omits the losses by plasma expansion and a helicon source are being tested.

  18. First results of the ITER-relevant negative ion beam test facility ELISE (invited).

    PubMed

    Fantz, U; Franzen, P; Heinemann, B; Wünderlich, D

    2014-02-01

    An important step in the European R&D roadmap towards the neutral beam heating systems of ITER is the new test facility ELISE (Extraction from a Large Ion Source Experiment) for large-scale extraction from a half-size ITER RF source. The test facility was constructed in the last years at Max-Planck-Institut für Plasmaphysik Garching and is now operational. ELISE is gaining early experience of the performance and operation of large RF-driven negative hydrogen ion sources with plasma illumination of a source area of 1 × 0.9 m(2) and an extraction area of 0.1 m(2) using 640 apertures. First results in volume operation, i.e., without caesium seeding, are presented.

  19. Experimental evaluation of a negative ion source for a heavy ionfusion negative ion driver

    SciTech Connect

    Grisham, L.R.; Hahto, S.K.; Hahto, S.T.; Kwan, J.W.; Leung, K.N.

    2005-01-18

    Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photodetached to neutrals [1,2,3]. To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm{sup 2} was obtained under the same conditions that gave 57 mA/cm{sup 2} of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that is used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl{sup -} was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 mA/cm{sup 2}, sufficient for present heavy ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source.

  20. Experimental Evaluation of a Negative Ion Source for a Heavy Ion Fusion Negative Ion Driver

    SciTech Connect

    Grisham, L. R.; Hahto, S. K.; Hahto, S. T.; Kwan, J. W.; Leung, K. N.

    2004-06-16

    Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photo-detached to neutrals. To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm{sup 2} was obtained under the same conditions that gave 57 45 mA/cm{sup 2} of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that i s used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl{sup -} was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 45 mA/cm{sup 2}, sufficient for present heavy ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source.

  1. Hydrogen evolution at the negative electrode of the all-vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Sun, Che-Nan; Delnick, Frank M.; Baggetto, Loïc; Veith, Gabriel M.; Zawodzinski, Thomas A.

    2014-02-01

    This work demonstrates a quantitative method to determine the hydrogen evolution rate occurring at the negative carbon electrode of the all vanadium redox flow battery (VRFB). Two carbon papers examined by buoyancy measurements yield distinct hydrogen formation rates (0.170 and 0.005 μmol min-1 g-1). The carbon papers have been characterized using electron microscopy, nitrogen gas adsorption, capacitance measurement by electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). We find that the specific electrochemical surface area (ECSA) of the carbon material has a strong influence on the hydrogen generation rate. This is discussed in light of the use of high surface area material to obtain high reaction rates in the VRFB.

  2. Development of spectrally selective imaging system for negative hydrogen ion source

    SciTech Connect

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

    2014-02-15

    A spectrally selective imaging system has been developed to obtain a distribution of H{sub α} emissions at the extraction region in a hydrogen negative ion source. The diagnostic system consisted of an aspherical lens, optical filters, a fiber image conduit, and a charge coupled device detector was installed on the 1/3-scaled hydrogen negative ion source in the National Institute for Fusion Science. The center of sight line passes beside the plasma grid (PG) surface with the distance of 11 mm, and the viewing angle has coverage 35 mm from the PG surface. Two dimensional H{sub α} distribution in the range up to 20 mm from the PG surface was clearly observed. The reduction area for H{sub α} emission caused by beam extraction was widely distributed in the extraction region near the PG surface.

  3. Cesium dynamics in long pulse operation of negative hydrogen ion sources for fusion

    SciTech Connect

    Fantz, U.; Wimmer, C.

    2012-02-15

    Large scale negative hydrogen ion sources operating stable for 1 h (cw mode) are required for the neutral beam heating system of the fusion experiment ITER. The formation of negative hydrogen ions relies on the surface effect for which cesium is evaporated into the source. In order to monitor the cesium dynamics the laser absorption spectroscopy technique is applied to the long pulse test facility MANITU. In the vacuum phase, without plasma operation the evaporation of cesium and the built-up of the cesium in the source are measured. Typical neutral cesium densities are 10{sup 15} m{sup -3}. During plasma operation and after the plasma phase a high cesium dynamics is observed, showing also depletion of cesium during long pulses with low cesium amount. The co-extracted electron current decreases with the cesium amount to a certain level whereas the ion current indicates an optimum density range.

  4. The First Observation of Intra Beam Stripping of Negative Hydrogen in a Superconducting Linear Accelerator

    SciTech Connect

    Aleksandrov, Alexander V; Plum, Michael A; Shishlo, Andrei P; Galambos, John D

    2012-01-01

    We report on an experiment in which a negative hydrogen ions beam in the Spallation Neutron Source (SNS) linear accelerator was replaced with a beam of protons with similar size and dynamics. Beam loss in the superconducting part of the SNS accelerator was at least an order of magnitude lower for the proton beam. Also beam loss has a stronger dependence on intensity with H- than with proton beams. These measurements verify a recent theoretical explanation of unexpected beam losses in the SNS superconducting linear accelerator based on an intra beam stripping mechanism for negative hydrogen ions. An identification of the new physics mechanism for beam loss is important for the design of new high current linear ion accelerators and the performance improvement of existing machines

  5. A collisional radiative model of hydrogen plasmas developed for diagnostic purposes of negative ion sources

    NASA Astrophysics Data System (ADS)

    Iordanova, Snejana; Paunska, Tsvetelina

    2016-02-01

    A collisional radiative model of low-pressure hydrogen plasmas is elaborated and applied in optical emission spectroscopy diagnostics of a single element of a matrix source of negative hydrogen ions. The model accounts for the main processes determining both the population densities of the first ten states of the hydrogen atom and the densities of the positive hydrogen ions H+, H2+, and H3+. In the calculations, the electron density and electron temperature are varied whereas the atomic and molecular temperatures are included as experimentally obtained external parameters. The ratio of the Hα to Hβ line intensities is calculated from the numerical results for the excited state population densities, obtained as a solution of the set of the steady-state rate balance equations. The comparison of measured and theoretically obtained ratios of line intensities yields the values of the electron density and temperature as well as of the degree of dissociation, i.e., of the parameters which have a crucial role for the volume production of the negative ions.

  6. Research progress on ionic plasmas generated in an intense hydrogen negative ion source

    SciTech Connect

    Takeiri, Y. Tsumori, K.; Nagaoka, K.; Kaneko, O.; Ikeda, K.; Nakano, H.; Kisaki, M.; Tokuzawa, T.; Osakabe, M.; Kondo, T.; Sato, M.; Shibuya, M.; Komada, S.; Sekiguchi, H.; Geng, S.

    2015-04-08

    Characteristics of ionic plasmas, observed in a high-density hydrogen negative ion source, are investigated with a multi-diagnostics system. The ionic plasma, which consists of hydrogen positive- and negative-ions with a significantly low-density of electrons, is generated in the ion extraction region, from which the negative ions are extracted through the plasma grid. The negative ion density, i.e., the ionic plasma density, as high as the order of 1×10{sup 17}m{sup −3}, is measured with cavity ring-down spectroscopy, while the electron density is lower than 1×10{sup 16}m{sup −3}, which is confirmed with millimeter-wave interferometer. Reduction of the negative ion density is observed at the negative ion extraction, and at that time the electron flow into the ionic plasma region is observed to conserve the charge neutrality. Distribution of the plasma potential is measured in the extraction region in the direction normal to the plasma grid surface with a Langmuir probe, and the results suggest that the sheath is formed at the plasma boundary to the plasma grid to which the bias voltage is applied. The beam extraction should drive the negative ion transport in the ionic plasma across the sheath formed on the extraction surface. Larger reduction of the negative ions at the beam extraction is observed in a region above the extraction aperture on the plasma grid, which is confirmed with 2D image measurement of the Hα emission and cavity ring-down spectroscopy. The electron distribution is also measured near the plasma grid surface. These various properties observed in the ionic plasma are discussed.

  7. First experiments with Cs doped Mo as surface converter for negative hydrogen ion sources

    SciTech Connect

    Schiesko, L. Hopf, C.; Höschen, T.; Meisl, G.; Encke, O.; Heinemann, B.; Fantz, U.; Cartry, G.; Amsalem, P.; Achkasov, K.

    2015-08-21

    A study was conducted on the properties of molybdenum implanted with caesium as an approach to reduce the Cs consumption of negative hydrogen ion sources based on evaporated Cs. The depth profiles of the implanted Cs were simulated by SDTrimSP and experimentally determined by X-ray photoelectron spectroscopy depth profiling. In particular, one year after implantation, the depth profiles showed no signs of Cs diffusion into the molybdenum, suggesting long term stability of the implanted Cs atoms. The H{sup −} surface generation mechanisms on the implanted samples in hydrogen plasma were investigated, and the stability of the H{sup −} yield during four hours low power hydrogen plasma discharges was demonstrated. An estimation of the work function reduction (−0.8 eV) by the Cs implantation was performed, and a comparison of the relative negative ion yields between the implanted samples and highly oriented pyrolitic graphite showed that the Cs doped Mo negative ion yield was larger.

  8. Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

    SciTech Connect

    Rauner, D.; Kurutz, U.; Fantz, U.

    2015-04-08

    As the negative hydrogen ion density n{sub H{sup −}} is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H{sup −} is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H{sup −} is produced in the plasma volume, laser photodetachment is applied as the standard method to measure n{sub H{sup −}}. The additional application of CRDS provides the possibility to directly obtain absolute values of n{sub H{sup −}}, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H{sup −} production and destruction processes. The modelled densities are adapted to the absolute measurements of n{sub H{sup −}} via CRDS, allowing to identify collisions of H{sup −} with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H{sup −} in the plasma volume at HOMER. Furthermore, the characteristic peak of n{sub H{sup −}} observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as n{sub e} determines

  9. Volume Production of Negative Hydrogen and Deuterium Ions in aReflex-Type Ion Source

    SciTech Connect

    Jimbo, K.; Ehlers, K.W.; Leung, K.N.; Pyle, R.V.

    1986-01-01

    The extraction of negative and positive hydrogen and deuterium ions from a reflex-type negative ion source has been investigated. Extracted positive and negative ion currents were measured as functions of the gas flow rate, the axial magnetic field, and the bias potential of the cylindrical wall of the arc-chamber. By biasing the cylindrical wall several volts negative relative to the anode, a maximum H{sup -} current of 9.7 mA(J{sup -} {approx_equal} 100 mA/cm{sup 2}) and D{sup -} current of 4.1 mA (J{sup -} {approx_equal} 42 mA/cm{sup 2})were obtained in steady state operation. This result shows a factor of two improvement over previous data. The total impurity negative ion content was less than 1%. When the source was arranged for positive ion extraction, a high proton ratio (90%) was observed. The extracted negative ion current was approximately as large as the positive ion current.

  10. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    SciTech Connect

    Valerio-Lizarraga, Cristhian A.; Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard; Leon-Monzon, Ildefonso; Midttun, Øystein

    2014-02-15

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  11. Multiplying probe for accurate power measurements on an RF driven atmospheric pressure plasma jet applied to the COST reference microplasma jet

    NASA Astrophysics Data System (ADS)

    Beijer, P. A. C.; Sobota, A.; van Veldhuizen, E. M.; Kroesen, G. M. W.

    2016-03-01

    In this paper a new multiplying probe for measuring the power dissipated in a miniature capacitively coupled, RF driven, atmospheric pressure plasma jet (μAPPJ—COST Reference Microplasma Jet—COST RMJ) is presented. The approach aims for substantially higher accuracy than provided by traditionally applied methods using bi-directional power meters or commercially available voltage and current probes in conjunction with digitizing oscilloscopes. The probe is placed on a miniature PCB and designed to minimize losses, influence of unknown elements, crosstalk and variations in temperature. The probe is designed to measure powers of the order of magnitude of 0.1-10 W. It is estimated that it measures power with less than 2% deviation from the real value in the tested power range. The design was applied to measure power dissipated in COST-RMJ running in helium with a small addition of oxygen.

  12. Extraction of negative hydrogen ions from a compact 14 GHz microwave ion source

    SciTech Connect

    Wada, M.; Kasuya, T.; Nishida, T.; Kenmotsu, T.; Maeno, S.; Nishiura, M.; Shinto, K.; Yamaoka, H.

    2012-02-15

    A pair of permanent magnets has formed enough intensity to realize electron cyclotron resonance condition for a 14 GHz microwave in a 2 cm diameter 9 cm long alumina discharge chamber. A three-electrode extraction system assembled in a magnetic shielding has formed a stable beam of negative hydrogen ions (H{sup -}) in a direction perpendicular to the magnetic field. The measured H{sup -} current density was about 1 mA/cm{sup 2} with only 50 W of discharge power, but the beam intensity had shown saturation against further increase in microwave power. The beam current decreased monotonically against increasing pressure.

  13. Extraction of negative hydrogen ions from a compact 14 GHz microwave ion source.

    PubMed

    Wada, M; Kasuya, T; Kenmotsu, T; Maeno, S; Nishida, T; Nishiura, M; Shinto, K; Yamaoka, H

    2012-02-01

    A pair of permanent magnets has formed enough intensity to realize electron cyclotron resonance condition for a 14 GHz microwave in a 2 cm diameter 9 cm long alumina discharge chamber. A three-electrode extraction system assembled in a magnetic shielding has formed a stable beam of negative hydrogen ions (H(-)) in a direction perpendicular to the magnetic field. The measured H(-) current density was about 1 mA∕cm(2) with only 50 W of discharge power, but the beam intensity had shown saturation against further increase in microwave power. The beam current decreased monotonically against increasing pressure.

  14. Caesium Free Negative Ion Sources for Neutral Beam Injectors: a Study of Negative Ion Production on Graphite Surface in Hydrogen and Deuterium Plasma

    SciTech Connect

    Schiesko, L.; Carrere, M.; Cartry, G.; Layet, J.-M.

    2009-03-12

    Negative ion generation on HOPG graphite surface has been studied in hydrogen and deuterium plasma. We measure Ion Distribution Function (IDF) of negative ions coming from graphite surface bombarded by positive ions in H{sub 2}/D{sub 2} plasmas. We showed that negative ions flux was proportional to positive ion flux and was strongly dependant on impinging energy. IDF study shows two generation mechanisms are involved: sputtering of adsorbed H/D as negative ions and, in a less important way, double electron capture. We compare H{sub 2}/D{sub 2} plasmas, and point out isotopic effect between H{sup -} and D{sup -} production.

  15. Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

    SciTech Connect

    Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

    2015-04-08

    A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H{sup −}) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H{sup −} current at higher frequency of cathode heating current.

  16. 3D modeling of the electron energy distribution function in negative hydrogen ion sources.

    PubMed

    Terasaki, R; Fujino, I; Hatayama, A; Mizuno, T; Inoue, T

    2010-02-01

    For optimization and accurate prediction of the amount of H-ion production in negative ion sources, analysis of electron energy distribution function (EEDF) is necessary. We are developing a numerical code which analyzes EEDF in the tandem-type arc-discharge source. It is a three-dimensional Monte Carlo simulation code with realistic geometry and magnetic configuration. Coulomb collision between electrons is treated with the "binary collision" model and collisions with hydrogen species are treated with the "null-collision" method. We applied this code to the analysis of the JAEA 10 A negative ion source. The numerical result shows that the obtained EEDF is in good agreement with experimental results.

  17. Dependence of beam emittance on plasma electrode temperature and rf-power, and filter-field tuning with center-gapped rod-filter magnets in J-PARC rf-driven H{sup −} ion source

    SciTech Connect

    Ueno, A. Koizumi, I.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

    2014-02-15

    The prototype rf-driven H{sup −} ion-source with a nickel plated oxygen-free-copper (OFC) plasma chamber, which satisfies the Japan Proton Accelerator Research Complex (J-PARC) 2nd stage requirements of a H{sup −} ion beam current of 60 mA within normalized emittances of 1.5 π mm mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 μs × 25 Hz) and a life-time of more than 50 days, was reported at the 3rd international symposium on negative ions, beams, and sources (NIBS2012). The experimental results of the J-PARC ion source with a plasma chamber made of stainless-steel, instead of nickel plated OFC used in the prototype source, are presented in this paper. By comparing these two sources, the following two important results were acquired. One was that the about 20% lower emittance was produced by the rather low plasma electrode (PE) temperature (T{sub PE}) of about 120 °C compared with the typically used T{sub PE} of about 200 °C to maximize the beam current for the plasma with the abundant cesium (Cs). The other was that by using the rod-filter magnets with a gap at each center and tuning the gap-lengths, the filter-field was optimized and the rf-power necessary to produce the J-PARC required H{sup −} ion beam current was reduced typically 18%. The lower rf-power also decreases the emittances.

  18. Dependence of beam emittance on plasma electrode temperature and rf-power, and filter-field tuning with center-gapped rod-filter magnets in J-PARC rf-driven H(-) ion source.

    PubMed

    Ueno, A; Koizumi, I; Ohkoshi, K; Ikegami, K; Takagi, A; Yamazaki, S; Oguri, H

    2014-02-01

    The prototype rf-driven H(-) ion-source with a nickel plated oxygen-free-copper (OFC) plasma chamber, which satisfies the Japan Proton Accelerator Research Complex (J-PARC) 2nd stage requirements of a H(-) ion beam current of 60 mA within normalized emittances of 1.5 π mm mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 μs × 25 Hz) and a life-time of more than 50 days, was reported at the 3rd international symposium on negative ions, beams, and sources (NIBS2012). The experimental results of the J-PARC ion source with a plasma chamber made of stainless-steel, instead of nickel plated OFC used in the prototype source, are presented in this paper. By comparing these two sources, the following two important results were acquired. One was that the about 20% lower emittance was produced by the rather low plasma electrode (PE) temperature (TPE) of about 120 °C compared with the typically used TPE of about 200 °C to maximize the beam current for the plasma with the abundant cesium (Cs). The other was that by using the rod-filter magnets with a gap at each center and tuning the gap-lengths, the filter-field was optimized and the rf-power necessary to produce the J-PARC required H(-) ion beam current was reduced typically 18%. The lower rf-power also decreases the emittances.

  19. The negative effects of hydrogenated trans fats and what to do about them.

    PubMed

    Kummerow, Fred A

    2009-08-01

    Partially hydrogenated vegetable oils have been in the American diet since 1900. More than 50 years ago they were found to contain trans fatty acids that were different from natural fatty acids in plant oils and in animal fat. There was growing evidence that the consumption of trans fats have negative health effects, including increasing plasma lipid levels. In 2003, the Food and Drug Administration (FDA) ruled that the amount of trans fat in a food item must be stated on the label after January 1, 2006; food items could be labeled 0% trans if they contain less than 0.5g/serving. Since the initial ruling, it is now known that the fatty acids in partially hydrogenated vegetable oil are 14 cis and trans isomers of octadecenoic and octadecadienoic acids that are formed during hydrogenation. They cause inflammation and calcification of arterial cells: known risk factors for coronary heart disease (CHD). They inhibit cyclooxygenase, an enzyme required for the conversion of arachidonic acid to prostacyclin, necessary for the regulation of blood flow. There have been several reformulations of hydrogenated fat containing varying amounts of trans fatty acids and linoleic acid, an essential fatty acid that is converted to arachidonic acid. Epidemiological data suggest that when trans fat percentages go up and linoleic acid percentages go down, death rates rise; when trans goes down, death rates go down. In spite of the harmful effects of trans fats, the FDA allows it in the food supply as long as the amount in a food item is declared on the label. Trans fat should be banned from the food supply.

  20. A collisional radiative model for caesium and its application to an RF source for negative hydrogen ions

    SciTech Connect

    Wünderlich, D. Wimmer, C.; Friedl, R.

    2015-04-08

    A collisional radiative (CR) model for caesium atoms in low-temperature, low-pressure hydrogen-caesium plasmas is introduced. This model includes the caesium ground state, 14 excited states, the singly charged caesium ion and the negative hydrogen ion. The reaction probabilities needed as input are based on data from the literature, using some scaling and extrapolations. Additionally, new cross sections for electron collision ionization and three-body recombination have been calculated. The relevance of mutual neutralization of positive caesium ions and negative hydrogen ions is highlighted: depending on the densities of the involved particle species, this excitation channel can have a significant influence on the population densities of excited states in the caesium atom. This strong influence is successfully verified by optical emission spectroscopy measurements performed at the IPP prototype negative hydrogen ion source for ITER NBI. As a consequence, population models for caesium in electronegative low-temperature, low-pressure hydrogen-caesium plasmas need to take into account the mutual neutralization process. The present CR model is an example for such models and represents an important prerequisite for deducing the total caesium density in surface production based negative hydrogen ion sources.

  1. Study on a negative hydrogen ion source with hot cathode arc discharge

    SciTech Connect

    Lin, S. H. Fang, X.; Zhang, H. J.; Qian, C.; Ma, B. H.; Wang, H.; Li, X. X.; Zhang, X. Z.; Sun, L. T.; Zhang, Z. M.; Yuan, P.; Zhao, H. W.

    2014-02-15

    A negative hydrogen (H{sup −}) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H{sup −} beam with ε {sub N,} {sub RMS} = 0.08 π mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I{sub e{sup −}}/I{sub H{sup −}} were experimentally studied. The discussion on the result, and opinions to improve the source were given.

  2. Over-the-barrier electron detachment in the hydrogen negative ion

    NASA Astrophysics Data System (ADS)

    Milošević, M. Z.; Simonović, N. S.

    2016-09-01

    The electron detachment from the hydrogen negative ion in strong fields is studied using the two-electron and different single-electron models within the quasistatic approximation. Special attention is payed to over-the-barrier regime where the Stark saddle is suppressed below the lowest energy level. It is demonstrated that the single-electron description of the lowest state of the ion, that is a good approximation for weak fields, fails in this and partially in the tunnelling regime. The exact lowest state energies and detachment rates for the ion at different strengths of the applied field are determined by solving the eigenvalue problem of the full two-electron Hamiltonian. A simple formula for the rate, which is valid in both regimes, is determined by fitting the exact data to the expression estimated using single-electron descriptions.

  3. Monitoring Surface Condition of Plasma Grid of a Negative Hydrogen Ion Source

    SciTech Connect

    Wada, M.; Kasuya, T.; Tokushige, S.; Kenmotsu, T.

    2011-09-26

    Surface condition of a plasma grid in a negative hydrogen ion source is controlled so as to maximize the beam current under a discharge operation with introducing Cs into the ion source. Photoelectric current induced by laser beams incident on the plasma grid can produce a signal to monitor the surface condition, but the signal detection can be easily hindered by plasma noise. Reduction in size of a detection electrode embedded in the plasma grid can improve signal-to-noise ratio of the photoelectric current from the electrode. To evaluate the feasibility of monitoring surface condition of a plasma gird by utilizing photoelectric effect, a small experimental setup capable of determining quantum yields of a surface in a cesiated plasma environment is being assembled. Some preliminary test results of the apparatus utilizing oxide cathodes are reported.

  4. Production of beam of negative hydrogen and deuterium ions from source with electron cyclotron resonance

    SciTech Connect

    Golovanivskii, K.S.; Dzhayamanna, K.; Dugar-Zhabon, V.D.

    1988-09-01

    The GELIOS-H/sup /minus// ion source is described; it has electron cyclotron resonance and is designed for generation of negative hydrogen and deuterium ions. The source consumes up to 100 W of microwave power at a frequency of 2.4 GHz and provides a stationary beam of H/sup /minus// ions of up to 1.5 mA and D/sup /minus// ions of up to 1.0 mA for an exit-aperture diameter of 6.2 mm and an extraction voltage of 4.5 kV. The life of the source is limited only by the life of the microwave generator.

  5. Negative hydrogen ion beam extracted from a Bernas-type ion source

    SciTech Connect

    Miyamoto, N.; Wada, M.

    2011-09-26

    Negative hydrogen (H{sup -}) ion beam was produced without cesium seeding by a Bernas-type ion source with a coaxial hot cathode. The amount of H{sup -} ion beam current extracted from an original Bernas-type ion source using a hairpin shape filament as a hot cathode was 1 {mu}A with the 0.4 A arc current, while that 300 eV beam energy. In the other hand, H{sup -} ion beam current using the Bernas-type ion source with a coaxial hot cathode reached 4 {mu}A under the same condition. Production efficiency was enhanced by the focused plasma produced by a coaxial hot cathode.

  6. 3D self-consistent modeling of a matrix source of negative hydrogen ions.

    PubMed

    Tarnev, Kh; Demerdjiev, A; Shivarova, A; Lishev, St

    2016-02-01

    The paper is in the scope of studies on the rf driving of a matrix source of negative hydrogen ions: a matrix of small radius discharges with planar-coil inductive driving and single aperture extraction from each discharge. The results from a three-dimensional model, in which plasma description is coupled to electrodynamics, confirm former conclusion that a single coil driving of the whole matrix by a zigzag coil with an omega-shaped conductor on the bottom of each discharge tube ensures efficient rf power deposition to the plasma. The latter is due to similarities with the rf driving of a single discharge by a single planar coil, shown by the obtained induced current and spatial distribution of the plasma parameters. Distinctions associated with the coil configuration as a single coil for the whole matrix are also discussed. PMID:26932005

  7. Electrical shielding box measurement of the negative hydrogen beam from Penning ion gauge ion source

    SciTech Connect

    Wang, T.; Yang, Z.; Dong, P.; Long, J. D.; He, X. Z.; Zhang, K. Z.; Zhang, L. W.; Wang, X.

    2012-06-15

    The cold-cathode Penning ion gauge (PIG) type ion source has been used for generation of negative hydrogen (H{sup -}) ions as the internal ion source of a compact cyclotron. A novel method called electrical shielding box dc beam measurement is described in this paper, and the beam intensity was measured under dc extraction inside an electrical shielding box. The results of the trajectory simulation and dc H{sup -} beam extraction measurement were presented. The effect of gas flow rate, magnetic field strength, arc current, and extraction voltage were also discussed. In conclusion, the dc H{sup -} beam current of about 4 mA from the PIG ion source with the puller voltage of 40 kV and arc current of 1.31 A was extrapolated from the measurement at low extraction dc voltages.

  8. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H(-) ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H(-) ion generation in volume-produced negative hydrogen ion sources. PMID:26931999

  9. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H(-) ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H(-) ion generation in volume-produced negative hydrogen ion sources.

  10. Single discharge of the matrix source of negative hydrogen ions: Influence of the neutral particle dynamics

    SciTech Connect

    Paunska, Ts.; Todorov, D. Shivarova, A.; Tarnev, Kh.

    2015-04-08

    The study presents two-dimensional (2D) fluid-plasma-model description of a planar-coil inductively-driven discharge, considered as a single element of a matrix source of volume-produced negative hydrogen ions. Whereas the models developed up to now have been directed towards description of the charged particle behavior in the discharge, including that of the negative ions, this model stresses on the role of the neutral particle dynamics and of the surface processes in the formation of the discharge structure. The latter is discussed based on comparison of results obtained for discharges in a flowing gas and at a constant gas pressure as well as for different values of the coefficient of atom recombination on the walls. The conclusions are that the main plasma parameters – electron density and temperature and plasma potential – determining the gas discharge regime stay stable, regardless of changes in the redistribution of the densities of the neutral particles and of the positive ions. With regards to the volume production of the ions, which requires high density of (vibrationally excited) molecules, the impact on the degree of dissociation of the coefficient of atom recombination on the wall is discussed.

  11. Negative Linear Compressibility in Organic Mineral Ammonium Oxalate Monohydrate with Hydrogen Bonding Wine-Rack Motifs.

    PubMed

    Qiao, Yuancun; Wang, Kai; Yuan, Hongsheng; Yang, Ke; Zou, Bo

    2015-07-16

    Negative linear compressibility (NLC) is a relatively uncommon phenomenon and rarely studied in organic systems. Here we provide the direct evidence of the persistent NLC in organic mineral ammonium oxalate monohydrate under high pressure using synchrotron X-ray powder diffraction, Raman spectroscopy and density functional theory (DFT) calculation. Synchrotron X-ray powder diffraction measurement reveals that ammonium oxalate monohydrate shows both positive and negative linear compressibility along b-axis before 11.5 GPa. The red shift of the external Raman modes and abnormal changes of several selected internal modes in high-pressure Raman spectra further confirmed the NLC. DFT calculations demonstrate that the N-H···O hydrogen bonding "wine-rack" motifs result in the NLC along b-axis in ammonium oxalate monohydrate. We anticipate the high-pressure study of ammonium oxalate monohydrate may represent a promising strategy for accelerating the pace of exploitation and improvement of NLC materials especially in organic systems. PMID:26266859

  12. Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources

    SciTech Connect

    Kuppel, S.; Matsushita, D.; Hatayama, A.; Bacal, M.

    2011-01-01

    This numerical study focuses on the physical mechanisms involved in the extraction of volume-produced H{sup -} ions from a steady state laboratory negative hydrogen ion source with one opening in the plasma electrode (PE) on which a dc-bias voltage is applied. A weak magnetic field is applied in the source plasma transversely to the extracted beam. The goal is to highlight the combined effects of the weak magnetic field and the PE bias voltage (upon the extraction process of H{sup -} ions and electrons). To do so, we focus on the behavior of electrons and volume-produced negative ions within a two-dimensional model using the particle-in-cell method. No collision processes are taken into account, except for electron diffusion across the magnetic field using a simple random-walk model at each time step of the simulation. The results show first that applying the magnetic field (without PE bias) enhances H{sup -} ion extraction, while it drastically decreases the extracted electron current. Secondly, the extracted H{sup -} ion current has a maximum when the PE bias is equal to the plasma potential, while the extracted electron current is significantly reduced by applying the PE bias. The underlying mechanism leading to the above results is the gradual opening by the PE bias of the equipotential lines towards the parts of the extraction region facing the PE. The shape of these lines is due originally to the electron trapping by the magnetic field.

  13. Plasma expansion across a transverse magnetic field in a negative hydrogen ion source for fusion

    NASA Astrophysics Data System (ADS)

    Fantz, U.; Schiesko, L.; Wünderlich, D.

    2014-08-01

    High power negative hydrogen ion sources operating at 0.3 Pa are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required large ion current at a tolerable number of co-extracted electrons the source is equipped with a magnetic filter field (up to 10 mT). The IPP prototype source (1/8 of the area of the ITER source) has been equipped with a flexible magnetic filter frame to perform filter field studies (position, polarity, strength). Axial profiles of the plasma parameters are measured with two Langmuir probes, positioned in the upper and the lower half of the expansion chamber. In addition to the expected decrease in electron temperature and density a vertical drift develops the direction depending on the polarity of the field. Without field no drift is observed. The drift is less pronounced in caesium seeded discharges and almost vanishes in deuterium, indicating an influence of the ion mass on the drift. A comparison with results from a half-size ITER source reveals that the plasma is much more uniform in the large source.

  14. Quantification Of Cesium In Negative Hydrogen Ion Sources By Laser Absorption Spectroscopy

    SciTech Connect

    Fantz, U.; Wimmer, Ch.

    2011-09-26

    The use of cesium in negative hydrogen ion sources and the resulting cesium dynamics caused by the evaporation and redistribution in the vacuum and plasma phase makes a reliable and on-line monitoring of the cesium amount in the source highly desirable. For that purpose, a robust and compact laser absorption setup suitable for the ion source environment has been developed utilizing the Cs D{sub 2} resonance line at 852.1 nm. First measurements are taken in a small laboratory plasma chamber with cesium evaporation. A detection limit of {approx_equal}5x10{sup 13} m{sup -3} at a typical path length of 15 cm has been obtained with a dynamic range of more than three orders of magnitude, limited by line saturation at high densities. For on-line monitoring an automatic data analysis is established achieving a temporal resolution of 100 ms. The setup has then been applied to the ITER prototype ion sources developed at IPP. It is been shown that the method is well suited for routine measurements revealing a new insight into the cesium dynamics during source operation and cesium conditioning.

  15. A discharge with a magnetic X-point as a negative hydrogen ion source

    SciTech Connect

    Tsankov, Tsanko; Czarnetzki, Uwe

    2011-09-26

    The study presents first results from investigations of a novel low-pressure plasma source, intended for a negative hydrogen ion production. The source utilizes a dc magnetic field, shaped to form a cusp with a magnetic null-point (X-point). Beside the common role of filtering out the high energy electrons, this magnetic field configuration ensures in the present case also an interesting mechanism of coupling the RF power to the plasma. Investigations performed using radio frequency modulation spectroscopy (RFMOS) reveal that the main power coupling to the electrons is confined in the region on one side of the X-point. The modulation of the light intensity indicates also the presence of a strong dc drift close to the plane of the X-point. Several hypothesises for its explanation are raised: an azimuthal diamagnetic drift due to strong axial gradients of the electron energy, the excitation of a standing helicon wave, which couples to the radial magnetic field in the plane of the X-point, or a Trivelpiece-Gould wave which is resonantly absorbed near the plane of the X-point.

  16. Characterisation of the properties of a negative hydrogen ion beam by several beam diagnostic techniques

    NASA Astrophysics Data System (ADS)

    Maurizio, R.; Fantz, U.; Bonomo, F.; Serianni, G.

    2016-06-01

    The beam properties of the BATMAN negative ion source, which is the prototype of one module of the source for the ITER neutral beam injection system, are characterised by means of three diagnostic techniques: beam emission spectroscopy (BES), the experimental calorimeter mini-STRIKE and a copper calorimeter. The main beam parameters—beam divergence, homogeneity and top-bottom asymmetries—are studied in different operational scenarios: with different magnetic filter field setups, source settings and with different gases (hydrogen or deuterium). Among all dependences, the influence of the magnetic field configuration on the beam and the evolution of the beam features during some conditioning days are investigated in detail. Data show that the stronger the filter field in the beam region, the higher the beam top-bottom asymmetry—likely a v× B effect. During the conditioning of the source, such vertical beam asymmetry increases as well, suggesting an inhomogeneous H -production at the first grid of the extraction system.

  17. Operation Status of the J-PARC Negative Hydrogen Ion Source

    SciTech Connect

    Oguri, H.; Ikegami, K.; Ohkoshi, K.; Namekawa, Y.; Ueno, A.

    2011-09-26

    A cesium-free negative hydrogen ion source driven with a lanthanum hexaboride (LaB{sub 6}) filament is being operated without any serious trouble for approximately four years in J-PARC. Although the ion source is capable of producing an H{sup -} ion current of more than 30 mA, the current is routinely restricted to approximately 16 mA at present for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The beam run is performed during 1 month cycle, which consisted of a 4-5 weeks beam operation and a few days down-period interval. At the recent beam run, approximately 700 h continuous operation was achieved. At every runs, the beam interruption time due to the ion source failure is a few hours, which correspond to the ion source availability of more than 99%. The R and D work is being performed in parallel with the operation in order to enhance the further beam current. As a result, the H{sup -} ion current of 61 mA with normalized rms emittance of 0.26 {pi}mm.mrad was obtained by adding a cesium seeding system to a J-PARC test ion source which has the almost same structure with the present J-PARC ion source.

  18. Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H{sup −} ion source

    SciTech Connect

    Ueno, A. Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

    2015-04-08

    In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H{sup −} ion beam of 60mA within normalized emittances of 1.5πmm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H{sup −} ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The maintenance and operation procedure to minimize the plasma chamber (PCH) replacement time on the beam line, which is very important to maximize the J-PARC beam time especially for an antenna failure, is presented in this paper. The PCH preserved by filling argon (Ar) gas inside after pre-conditioning including pre-cesiation to produce the required beam at a test-stand successfully produced the required beam on the beam line with slight addition of cesium (Cs). The methods of the feedback controls of a 2MHz-RF-matching, an H{sup −} ion beam intensity and the addition of Cs are also presented. The RF-matching feedback by using two vacuum variable capacitors (VVCs) and RF-frequency shift produced the almost perfect matching with negligibly small reflected RF-power. The H{sup −} ion beam intensity was controlled within errors of ±0.1mA by the RF-power feedback. The amount of Cs was also controlled by remotely opening a Cs-valve to keep the RF-power lower than a settled value.

  19. Effects of roughness and temperature on low-energy hydrogen positive and negative ion reflection from silicon and carbon surfaces

    SciTech Connect

    Tanaka, N.; Kato, S.; Miyamoto, T.; Wada, M.; Nishiura, M.; Tsumori, K.; Matsumoto, Y.; Kenmotsu, T.; Okamoto, A.; Kitajima, S.; Sasao, M.; Yamaoka, H.

    2014-02-15

    Angle-resolved energy distribution functions of positive and negative hydrogen ions produced from a rough-finished Si surface under 1 keV proton irradiation have been measured. The corresponding distribution from a crystalline surface and a carbon surface are also measured for comparison. Intensities of positive and negative ions from the rough-finished Si are substantially smaller than those from crystalline Si. The angular distributions of these species are broader for rough surface than the crystalline surface. No significant temperature dependence for positive and negative ion intensities is observed for all samples in the temperature range from 300 to 400 K.

  20. Effects of roughness and temperature on low-energy hydrogen positive and negative ion reflection from silicon and carbon surfaces.

    PubMed

    Tanaka, N; Kato, S; Miyamoto, T; Nishiura, M; Tsumori, K; Matsumoto, Y; Kenmotsu, T; Okamoto, A; Kitajima, S; Sasao, M; Wada, M; Yamaoka, H

    2014-02-01

    Angle-resolved energy distribution functions of positive and negative hydrogen ions produced from a rough-finished Si surface under 1 keV proton irradiation have been measured. The corresponding distribution from a crystalline surface and a carbon surface are also measured for comparison. Intensities of positive and negative ions from the rough-finished Si are substantially smaller than those from crystalline Si. The angular distributions of these species are broader for rough surface than the crystalline surface. No significant temperature dependence for positive and negative ion intensities is observed for all samples in the temperature range from 300 to 400 K.

  1. Negative Regulation of NADPH Oxidase 4 by Hydrogen Peroxide-inducible Clone 5 (Hic-5) Protein*

    PubMed Central

    Desai, Leena P.; Zhou, Yong; Estrada, Aida V.; Ding, Qiang; Cheng, Guangjie; Collawn, James F.; Thannickal, Victor J.

    2014-01-01

    Hydrogen peroxide-inducible clone 5 (Hic-5) is a focal adhesion adaptor protein induced by the profibrotic cytokine TGF-β1. We have demonstrated previously that TGF-β1 induces myofibroblast differentiation and lung fibrosis by activation of the reactive oxygen species-generating enzyme NADPH oxidase 4 (Nox4). Here we investigated a potential role for Hic-5 in regulating Nox4, myofibroblast differentiation, and senescence. In normal human diploid fibroblasts, TGF-β1 induces Hic-5 expression in a delayed manner relative to the induction of Nox4 and myofibroblast differentiation. Hic-5 silencing induced constitutive Nox4 expression and enhanced TGF-β1-inducible Nox4 levels. The induction of constitutive Nox4 protein in Hic-5-silenced cells was independent of transcription and translation and controlled by the ubiquitin-proteasomal system. Hic-5 associates with the ubiquitin ligase Cbl-c and the ubiquitin-binding protein heat shock protein 27 (HSP27). The interaction of these proteins is required for the ubiquitination of Nox4 and for maintaining low basal levels of this reactive oxygen species-generating enzyme. Our model suggests that TGF-β1-induced Hic-5 functions as a negative feedback mechanism to limit myofibroblast differentiation and senescence by promoting the ubiquitin-proteasomal system-mediated degradation of Nox4. Together, these studies indicate that endogenous Hic-5 suppresses senescence and profibrotic activities of myofibroblasts by down-regulating Nox4 protein expression. Additionally, these are the first studies, to our knowledge, to demonstrate posttranslational regulation of Nox4. PMID:24831009

  2. Modelling the ion source for ITER NBI: from the generation of negative hydrogen ions to their extraction

    NASA Astrophysics Data System (ADS)

    Wünderlich, D.; Mochalskyy, S.; Fantz, U.; Franzen, P.; the NNBI-Team

    2014-02-01

    The neutral beam injection (NBI) system for ITER is based on a large (Asource = 1.9 × 0.9 m2) negative hydrogen or deuterium ion source. In this source negative ions are produced in a low-pressure (pfill ≈ 0.3 Pa) plasma by conversion of atoms and protons on a caesiated molybdenum surface with low work function. Then the negative ions are transported through the plasma to the extraction system where extraction of these ions and co-extraction of electrons also take place. This paper describes the status of the modelling activities connected with the negative ion test facilities of IPP Garching. It is illustrated that these modelling activities constitute a strong support of the experimental activities connected with the development of the negative ion source for ITER NBI. Several numerical codes developed in the past years—in close collaboration with the experiment—and their results are introduced. Focus is laid on the production, transport and extraction of negative hydrogen ions and on the inevitable co-extraction of electrons.

  3. Hydrogen Peroxide Linked to Lysine Oxidase Activity Facilitates Biofilm Differentiation and Dispersal in Several Gram-Negative Bacteria▿

    PubMed Central

    Mai-Prochnow, Anne; Lucas-Elio, Patricia; Egan, Suhelen; Thomas, Torsten; Webb, Jeremy S.; Sanchez-Amat, Antonio; Kjelleberg, Staffan

    2008-01-01

    The marine bacterium Pseudoalteromonas tunicata produces an antibacterial and autolytic protein, AlpP, which causes death of a subpopulation of cells during biofilm formation and mediates differentiation, dispersal, and phenotypic variation among dispersal cells. The AlpP homologue (LodA) in the marine bacterium Marinomonas mediterranea was recently identified as a lysine oxidase which mediates cell death through the production of hydrogen peroxide. Here we show that AlpP in P. tunicata also acts as a lysine oxidase and that the hydrogen peroxide generated is responsible for cell death within microcolonies during biofilm development in both M. mediterranea and P. tunicata. LodA-mediated biofilm cell death is shown to be linked to the generation of phenotypic variation in growth and biofilm formation among M. mediterranea biofilm dispersal cells. Moreover, AlpP homologues also occur in several other gram-negative bacteria from diverse environments. Our results show that subpopulations of cells in microcolonies also die during biofilm formation in two of these organisms, Chromobacterium violaceum and Caulobacter crescentus. In all organisms, hydrogen peroxide was implicated in biofilm cell death, because it could be detected at the same time as the killing occurred, and the addition of catalase significantly reduced biofilm killing. In C. violaceum the AlpP-homologue was clearly linked to biofilm cell death events since an isogenic mutant (CVMUR1) does not undergo biofilm cell death. We propose that biofilm killing through hydrogen peroxide can be linked to AlpP homologue activity and plays an important role in dispersal and colonization across a range of gram-negative bacteria. PMID:18502869

  4. Study of negative hydrogen ion beam optics using the 3D3V PIC model

    SciTech Connect

    Miyamoto, K.; Nishioka, S.; Goto, I.; Hatayama, A.; Hanada, M.; Kojima, A.

    2015-04-08

    The mechanism of negative ion extraction under real conditions with the complex magnetic field is studied by using the 3D PIC simulation code. The extraction region of the negative ion source for the negative ion based neutral beam injection system in fusion reactors is modelled. It is shown that the E x B drift of electrons is caused by the magnetic filter and the electron suppression magnetic field, and the resultant asymmetry of the plasma meniscus. Furthermore, it is indicated that that the asymmetry of the plasma meniscus results in the asymmetry of negative ion beam profile including the beam halo. It could be demonstrated theoretically that the E x B drift is not significantly weakened by the elastic collisions of the electrons with neutral particles.

  5. Tests on the extracted current density of negative hydrogen ions from a single element of the matrix source

    SciTech Connect

    Lishev, St.; Yordanov, D. Shivarova, A.

    2015-04-08

    Concepts for the extraction of volume-produced negative hydrogen ions from a rf matrix source (a matrix of small-radius discharges with a planar-coil inductive driving) are presented and discussed based on experimental results for the current densities of the extracted ions and the co-extracted electrons. The experiment has been carried out in a single discharge of the source: a rf discharge with a radius of 2.25 cm inductively driven by a 3.5-turn planar coil. The length of the discharge tube, the area of the reference electrode inserted in the discharge volume, the discharge modes, the magnetic filter and its position along the discharge length, the position of the permanent magnets for the separation of the co-extracted electrons from the extracted ions in the extraction device and the bias applied to its first electrode are considered as factors influencing the extracted currents of negative ions.

  6. Photodetachment Spectrum of Hydrogen Negative Ion Near a Partially Reflecting Spherical Surface

    NASA Astrophysics Data System (ADS)

    Afaq, A.; Iqbal, Azmat; Rahman, Amin Ur; Khan, Naveed; Aleem, Fazal-e.-; Ansari, M. Mushraf

    2016-10-01

    Photodetachment of negative ions near surfaces is of great interest in view of its fundamental significance and technological applications. We reinvestigate the dynamics of photoelectrons in H - photodetachment near a partially reflecting spherical surface by the semiclassical closed-orbit theory. Reflection parameter R and curvature K is used to observe inelastic and spherical effects of the surface, respectively. The classical action is evaluated from the photodetached electron trajectories incident normally at the surface, arising simultaneously from the source and its image. The derived analytical formula of photodetachment cross section correctly recovers the results of reflective spherical surface published recently based on theoretical imaging method.

  7. Cross sections of one- and two-photon detachment of the hydrogen negative ion

    NASA Astrophysics Data System (ADS)

    Pazdzersky, V. A.; Usachenko, V. I.; Ushnurtsev, A. V.

    2000-03-01

    The model non-local separable Yamaguchi potential is proposed as being particularly appropriate for the description of the interaction of a detached electron with its parent residual atomic core in a theoretical treatment of the processes of H- negative ion multiphoton detachment in a monochromatic electromagnetic (EM) field of both linear and circular polarization. Within the framework of that model we derive exact analytical expressions for the cross sections of the one- and two-photon H- detachment processes in the lowest orders of perturbation theory on EM interaction of the detached electron with an ionizing field and studied the effect of various values of the problem parameters. We show that both obtained cross sections are in good agreement with the values measured in relevant experiments and the best results calculated by other authors with different (but much more sophisticated and complicated) approaches and methods.

  8. Transport properties of bare and hydrogenated zigzag silicene nanoribbons: Negative differential resistances and perfect spin-filtering effects

    NASA Astrophysics Data System (ADS)

    Yang, X. F.; Liu, Y. S.; Feng, J. F.; Wang, X. F.; Zhang, C. W.; Chi, F.

    2014-09-01

    Ab initio calculations are performed to investigate the spin-polarized transport properties of the bare and hydrogenated zigzag silicene nanoribbons (ZSiNRs). The results show that the ZSiNRs with symmetric (asymmetric) edges prefer the ferromagnetic (antiferromagnetic) as their ground states with the semiconductor properties, while the accordingly antiferromagnetic (ferromagnetic) states exhibit the metallic behaviors. These facts result in a giant magnetoresistance behavior between the ferromagnetic and antiferromagnetic states in the low bias-voltage regime. Moreover, in the ferromagnetic ZSiNRs with asymmetric edges, a perfect spin-filtering effect with 100% positive electric current polarization can be achieved by altering the bias voltage. In addition, we also find that the negative differential resistances prefer the metastable states. The findings here indicate that the asymmetric and symmetric ZSiNRs are promising materials for spintronic applications.

  9. Transport properties of bare and hydrogenated zigzag silicene nanoribbons: Negative differential resistances and perfect spin-filtering effects

    SciTech Connect

    Yang, X. F.; Liu, Y. S. Feng, J. F.; Wang, X. F.; Zhang, C. W.; Chi, F.

    2014-09-28

    Ab initio calculations are performed to investigate the spin-polarized transport properties of the bare and hydrogenated zigzag silicene nanoribbons (ZSiNRs). The results show that the ZSiNRs with symmetric (asymmetric) edges prefer the ferromagnetic (antiferromagnetic) as their ground states with the semiconductor properties, while the accordingly antiferromagnetic (ferromagnetic) states exhibit the metallic behaviors. These facts result in a giant magnetoresistance behavior between the ferromagnetic and antiferromagnetic states in the low bias-voltage regime. Moreover, in the ferromagnetic ZSiNRs with asymmetric edges, a perfect spin-filtering effect with 100% positive electric current polarization can be achieved by altering the bias voltage. In addition, we also find that the negative differential resistances prefer the metastable states. The findings here indicate that the asymmetric and symmetric ZSiNRs are promising materials for spintronic applications.

  10. Development of a Negative Hydrogen Ion Source for Spatial Beam Profile Measurement of a High Intensity Positive Ion Beam

    SciTech Connect

    Shinto, Katsuhiro; Wada, Motoi; Nishida, Tomoaki; Demura, Yasuhiro; Sasaki, Daichi; Tsumori, Katsuyoshi; Nishiura, Masaki; Kaneko, Osamu; Kisaki, Masashi; Sasao, Mamiko

    2011-09-26

    We have been developing a negative hydrogen ion (H{sup -} ion) source for a spatial beam profile monitor of a high intensity positive ion beam as a new diagnostic tool. In case of a high intensity continuous-wave (CW) deuteron (D{sup +}) beam for the International Fusion Materials Irradiation Facility (IFMIF), it is difficult to measure the beam qualities in the severe high radiation environment during about one-year cyclic operation period. Conventional techniques are next to unusable for diagnostics in the operation period of about eleven months and for maintenance in the one-month shutdown period. Therefore, we have proposed an active beam probe system by using a negative ion beam and started an experimental study for the proof-of-principle (PoP) of the new spatial beam profile monitoring tool. In this paper, we present the status of development of the H{sup -} ion source as a probe beam source for the PoP experiment.

  11. Global model analysis of negative ion generation in low-pressure inductively coupled hydrogen plasmas with bi-Maxwellian electron energy distributions

    SciTech Connect

    Huh, Sung-Ryul; Kim, Nam-Kyun; Jung, Bong-Ki; Chung, Kyoung-Jae; Hwang, Yong-Seok; Kim, Gon-Ho

    2015-03-15

    A global model was developed to investigate the densities of negative ions and the other species in a low-pressure inductively coupled hydrogen plasma with a bi-Maxwellian electron energy distribution. Compared to a Maxwellian plasma, bi-Maxwellian plasmas have higher populations of low-energy electrons and highly vibrationally excited hydrogen molecules that are generated efficiently by high-energy electrons. This leads to a higher reaction rate of the dissociative electron attachment responsible for negative ion production. The model indicated that the bi-Maxwellian electron energy distribution at low pressures is favorable for the creation of negative ions. In addition, the electron temperature, electron density, and negative ion density calculated using the model were compared with the experimental data. In the low-pressure regime, the model results of the bi-Maxwellian electron energy distributions agreed well quantitatively with the experimental measurements, unlike those of the assumed Maxwellian electron energy distributions that had discrepancies.

  12. Optimization of plasma parameters with magnetic filter field and pressure to maximize H- ion density in a negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Cho, Won-Hwi; Dang, Jeong-Jeung; Kim, June Young; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-02-01

    Transverse magnetic filter field as well as operating pressure is considered to be an important control knob to enhance negative hydrogen ion production via plasma parameter optimization in volume-produced negative hydrogen ion sources. Stronger filter field to reduce electron temperature sufficiently in the extraction region is favorable, but generally known to be limited by electron density drop near the extraction region. In this study, unexpected electron density increase instead of density drop is observed in front of the extraction region when the applied transverse filter field increases monotonically toward the extraction aperture. Measurements of plasma parameters with a movable Langmuir probe indicate that the increased electron density may be caused by low energy electron accumulation in the filter region decreasing perpendicular diffusion coefficients across the increasing filter field. Negative hydrogen ion populations are estimated from the measured profiles of electron temperatures and densities and confirmed to be consistent with laser photo-detachment measurements of the H- populations for various filter field strengths and pressures. Enhanced H- population near the extraction region due to the increased low energy electrons in the filter region may be utilized to increase negative hydrogen beam currents by moving the extraction position accordingly. This new finding can be used to design efficient H- sources with an optimal filtering system by maximizing high energy electron filtering while keeping low energy electrons available in the extraction region.

  13. Optimization of plasma parameters with magnetic filter field and pressure to maximize H⁻ ion density in a negative hydrogen ion source.

    PubMed

    Cho, Won-Hwi; Dang, Jeong-Jeung; Kim, June Young; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    Transverse magnetic filter field as well as operating pressure is considered to be an important control knob to enhance negative hydrogen ion production via plasma parameter optimization in volume-produced negative hydrogen ion sources. Stronger filter field to reduce electron temperature sufficiently in the extraction region is favorable, but generally known to be limited by electron density drop near the extraction region. In this study, unexpected electron density increase instead of density drop is observed in front of the extraction region when the applied transverse filter field increases monotonically toward the extraction aperture. Measurements of plasma parameters with a movable Langmuir probe indicate that the increased electron density may be caused by low energy electron accumulation in the filter region decreasing perpendicular diffusion coefficients across the increasing filter field. Negative hydrogen ion populations are estimated from the measured profiles of electron temperatures and densities and confirmed to be consistent with laser photo-detachment measurements of the H(-) populations for various filter field strengths and pressures. Enhanced H(-) population near the extraction region due to the increased low energy electrons in the filter region may be utilized to increase negative hydrogen beam currents by moving the extraction position accordingly. This new finding can be used to design efficient H(-) sources with an optimal filtering system by maximizing high energy electron filtering while keeping low energy electrons available in the extraction region. PMID:26932018

  14. Importance of electric field for H{sup -} extraction in a volume-type hydrogen negative ion source

    SciTech Connect

    Matsumoto, Y.; Nishiura, M.; Sasao, M.; Yamaoka, H.; Shinto, K.; Wada, M.

    2008-02-15

    The effect upon extraction of negative hydrogen ions (H{sup -}) due to electric field near the extractor hole of a H{sup -} source is studied experimentally and theoretically. Probe measurements show that the extraction electric field penetrates into the plasma in the region near the extractor hole. Based on this observation a three-dimensional H{sup -} trajectory calculation that takes into account the local electric field distribution near the plasma electrode has been carried out. The validity of the trajectory calculation was examined by comparing the results with experimentally measured changes in H{sup -} current detected by a Faraday cup due to irradiation of a pulse laser beam in the region close to the extractor hole. The calculation results qualitatively explain the changes in H{sup -} current observed in the experiment. The calculation results also predict that the amount of H{sup -} current passing through the extractor hole changes with the electric field: the penetration of the electric field substantially enhances the H{sup -} extraction current, because it produces an electric field to attract H{sup -} toward the extraction hole.

  15. Endothelial nitric oxide synthase negatively regulates hydrogen peroxide-stimulated AMP-activated protein kinase in endothelial cells.

    PubMed

    Jin, Benjamin Y; Sartoretto, Juliano L; Gladyshev, Vadim N; Michel, Thomas

    2009-10-13

    Hydrogen peroxide and other reactive oxygen species are intimately involved in endothelial cell signaling. In many cell types, the AMP-activated protein kinase (AMPK) has been implicated in the control of metabolic responses, but the role of endothelial cell redox signaling in the modulation of AMPK remains to be completely defined. We used RNA interference and pharmacological methods to establish that H(2)O(2) is a critical activator of AMPK in cultured bovine aortic endothelial cells (BAECs). H(2)O(2) treatment of BAECs rapidly and significantly increases the phosphorylation of AMPK. The EC(50) for H(2)O(2)-promoted phosphorylation of AMPK is 65 + or - 15 microM, within the physiological range of cellular H(2)O(2) concentrations. The Ca(2+)/calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) inhibitor STO-609 abolishes H(2)O(2)-dependent AMPK activation, whereas eNOS inhibitors enhance AMPK activation. Similarly, siRNA-mediated knockdown of CaMKKbeta abrogates AMPK activation, whereas siRNA-mediated knockdown of eNOS leads to a striking increase in AMPK phosphorylation. Cellular imaging studies using the H(2)O(2) biosensor HyPer show that siRNA-mediated eNOS knockdown leads to a marked increase in intracellular H(2)O(2) generation, which is blocked by PEG-catalase. eNOS(-/-) mice show a marked increase in AMPK phosphorylation in liver and lung compared to wild-type mice. Lung endothelial cells from eNOS(-/-) mice also show a significant increase in AMPK phosphorylation. Taken together, these results establish that CaMKKbeta is critically involved in mediating the phosphorylation of AMPK promoted by H(2)O(2) in endothelial cells, and document that eNOS is an important negative regulator of AMPK phosphorylation and intracellular H(2)O(2) generation in endothelial cells. PMID:19805165

  16. Femtosecond Hydrogen Bond Dynamics of Bulk-like and Bound Water at Positively and Negatively Charged Lipid Interfaces Revealed by 2D HD-VSFG Spectroscopy.

    PubMed

    Singh, Prashant Chandra; Inoue, Ken-Ichi; Nihonyanagi, Satoshi; Yamaguchi, Shoichi; Tahara, Tahei

    2016-08-26

    Interfacial water in the vicinity of lipids plays an important role in many biological processes, such as drug delivery, ion transportation, and lipid fusion. Hence, molecular-level elucidation of the properties of water at lipid interfaces is of the utmost importance. We report the two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) study of the OH stretch of HOD at charged lipid interfaces, which shows that the hydrogen bond dynamics of interfacial water differ drastically, depending on the lipids. The data indicate that the spectral diffusion of the OH stretch at a positively charged lipid interface is dominated by the ultrafast (<∼100 fs) component, followed by the minor sub-picosecond slow dynamics, while the dynamics at a negatively charged lipid interface exhibit sub-picosecond dynamics almost exclusively, implying that fast hydrogen bond fluctuation is prohibited. These results reveal that the ultrafast hydrogen bond dynamics at the positively charged lipid-water interface are attributable to the bulk-like property of interfacial water, whereas the slow dynamics at the negatively charged lipid interface are due to bound water, which is hydrogen-bonded to the hydrophilic head group. PMID:27482947

  17. Small radio frequency driven multicusp ion source for positive hydrogen ion beam production

    SciTech Connect

    Perkins, L.T.; Herz, P.R.; Leung, K.N.; Pickard, D.S. )

    1994-04-01

    A compact, 2.5 cm diam rf-driven multicusp ion source has been developed and tested for H[sup +] ion production in pulse mode operation. The source is optimized for atomic hydrogen ion species and extractable current. It is found that hydrogen ion beam current densities in excess of 650 mA/cm[sup 2] can be achieved with H[sup +] species above 80%. The geometry and position of the porcelain-coated copper antenna were found to be of great significance in relation to the efficiency of the ion source.

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

    NASA Astrophysics Data System (ADS)

    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

  19. Negative ion-driven associated particle neutron generator

    DOE PAGES

    Antolak, A. J.; Leung, K. N.; Morse, D. H.; Donovan, D. C.; Chames, J. M.; Whaley, J. A.; Buchenauer, D. A.; Chen, A. X.; Hausladen, P. A.; Liang, F.

    2015-10-09

    We describe an associated particle neutron generator that employs a negative ion source to produce high neutron flux from a small source size. Furthermore, negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). Finally, the neutron generator can operate in eithermore » pulsed or continuous-wave (cw) mode and has been demonstrated to produce 106 D-D n/s (equivalent to similar to 108 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.« less

  20. Negative ion-driven associated particle neutron generator

    SciTech Connect

    Antolak, A. J.; Leung, K. N.; Morse, D. H.; Donovan, D. C.; Chames, J. M.; Whaley, J. A.; Buchenauer, D. A.; Chen, A. X.; Hausladen, P. A.; Liang, F.

    2015-10-09

    We describe an associated particle neutron generator that employs a negative ion source to produce high neutron flux from a small source size. Furthermore, negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). Finally, the neutron generator can operate in either pulsed or continuous-wave (cw) mode and has been demonstrated to produce 106 D-D n/s (equivalent to similar to 108 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.

  1. A spin-Seebeck diode with a negative differential spin-Seebeck effect in a hydrogen-terminated zigzag silicene nanoribbon heterojunction.

    PubMed

    Fu, Hua-Hua; Gu, Lei; Wu, Dan-Dan

    2016-05-14

    The spin-Seebeck effect (SSE), the central topic of spin caloritronics, provides a new direction for future low power consumption technology. To realize device applications of SSE, a spin-Seebeck diode (SSD) with a negative differential SSE is very desirable. To this end, we constructed a spin caloritronics device that was composed of a ferromagnetic double-single-hydrogen-terminated zigzag silicene nanoribbon (ZSiNR-H2-H) and an antiferromagnetic double-double-hydrogen-terminated zigzag silicene nanoribbon (ZSiNR-H2-H2). By using ab initio calculations combined with nonequilibrium Green's function technique, we found that thermally driven spin current through the heterojunction featured the SSD effect and negative differential SSE. The former originates from the asymmetrical thermal-driven conducting electrons and holes, and the latter ascribes to the thermal spin compensation effect. Their physical mechanisms are much different from the previous ones mainly relying on the spin-wave excitations in the interface between metals and magnetic insulators, supporting our study that puts forward a new route to realize the SSD with a negative differential SSE. PMID:27098900

  2. Doppler shift measurement of Balmer-alpha line spectrum emission from a plasma in a negative hydrogen ion source

    SciTech Connect

    Wada, M. Doi, K.; Kisaki, M.; Nakano, H.; Tsumori, K.; Nishiura, M.

    2015-04-08

    Balmer-α light emission from the extraction region of the LHD one-third ion source has shown a characteristic Doppler broadening in the wavelength spectrum detected by a high resolution spectrometer. The spectrum resembles Gaussian distribution near the wavelength of the intensity peak, while it has an additional component of a broader foot. The measured broadening near the wavelength of the intensity peak corresponds to 0.6 eV hydrogen atom temperature. The spectrum exhibits a larger expansion in the blue wing which becomes smaller when the line of sight is tilted toward the driver region from the original observation axis parallel to the plasma grid. A surface collision simulation model predicts the possibility of hydrogen reflection at the plasma grid surface to form a broad Balmer-α light emission spectrum.

  3. Single element of the matrix source of negative hydrogen ions: Measurements of the extracted currents combined with diagnostics.

    PubMed

    Yordanov, D; Lishev, St; Shivarova, A

    2016-02-01

    Combining measurements of the extracted currents with probe and laser-photodetachment diagnostics, the study is an extension of recent tests of factors and gas-discharge conditions stimulating the extraction of volume produced negative ions. The experiment is in a single element of a rf source with the design of a matrix of small-radius inductively driven discharges. The results are for the electron and negative-ion densities, for the plasma potential and for the electronegativity in the vicinity of the plasma electrode as well as for the currents of the extracted negative ions and electrons. The plasma-electrode bias and the rf power have been varied. Necessity of a high bias to the plasma electrode and stable linear increase of the extracted currents with the rf power are the main conclusions.

  4. H{sup -} beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source

    SciTech Connect

    Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N.; Tsumori, K.; Takeiri, Y.

    2012-02-15

    H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.

  5. Expansion of a plasma across a transverse magnetic field in a negative hydrogen ion source for fusion

    NASA Astrophysics Data System (ADS)

    Fantz, Ursel; Schiesko, Loic; Wünderlich, Dirk

    2012-10-01

    Negative ion sources are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required ion current of 40 A at a tolerable amount of co-extracted electrons (electron to ion ratio below one) the source is separated into a plasma generation region and an expansion chamber equipped with a magnetic filter field (up to 10 mT). The field is needed for: (1) cooling the electrons down and thus minimize the H^- destruction by collisions, (2) to reduce the co-extracted electron current, and (3) to enhance the extraction probability for the surface produced negative ions. The area of the ITER source will be approximately 1m width and 2 m height, the IPP prototype source is a 1/8-size source. The recently installed flexible magnetic filter frame allows for systematic filter field studies (strength, position, polarity). Two Langmuir probes have been used to measure the plasma parameters simultaneously in axial direction. The profiles in the upper and lower part of the expansion chamber show beside the expected electron temperature and density decrease a drop in the plasma potential and a drift depending on the polarity, which vanishes when removing the filter field. The data interpretation is supported by modeling activities.

  6. Influence of electric field penetration by a three-electrode beam extraction system on hydrogen negative ion source plasma

    NASA Astrophysics Data System (ADS)

    Matsumoto, Y.; Nishiura, M.; Yamaoka, H.; Sasao, M.; Wada, M.

    2014-02-01

    We study influence of electric field penetration into H- ion source plasma with three-electrode beam extraction system. Clear change in the plasma potential due to the field penetration is observed in case of low gap voltage between a plasma electrode and an extraction electrode. Influence of lens voltage on the second electrode, which is normally utilized to focus the extracted beam, on ion source plasma is evaluated separating contributions of H- density in the plasma and extraction probability of H- ions from the plasma by two kinds of photodetachment techniques. In our operation condition, we found that the lens voltage is also useful to enhance the H- density in the plasma, though it negatively affects the extraction probability.

  7. Hydrogen negative ion production in a 14 GHz electron cyclotron resonance compact ion source with a cone-shaped magnetic filter

    SciTech Connect

    Ichikawa, T.; Kasuya, T.; Wada, M.; Kenmotsu, T.; Maeno, S.; Nishiura, M.; Shimozuma, T.; Yamaoka, H.

    2014-02-15

    The plasma electrode structure of a 14 GHz ECR ion source was modified to enlarge the plasma volume of low electron temperature region. The result shows that the extracted beam current reached about 0.6 mA/cm{sup 2} with about 40 W microwave power. To investigate the correlation between the volume of the low electron temperature region and the H{sup −} current, a vacuum ultraviolet (VUV) spectrometer had been installed to observe light emission in the VUV wavelength range from the plasma. From the results of the negative ion beam current and that from VUV spectrometry, production rate of vibrationally excited hydrogen molecule seems to be enhanced by increasing the volume of low electron temperature region.

  8. Negative catalytic effect of water on the reactivity of hydrogen abstraction from the C-H bond of dimethyl ether by deuterium atoms through tunneling at low temperatures

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Watanabe, Naoki; Kouchi, Akira

    2016-10-01

    We report an experimental study on the catalytic effect of solid water on the reactivity of hydrogen abstraction (H-abstraction) from dimethyl ether (DME) in the low-temperature solid DME-H2O complex. When DME reacted with deuterium atoms on a surface at 15-25 K, it was efficiently deuterated via successive tunneling H-abstraction and deuterium (D)-addition reactions. The 'effective' rate constant for DME-H2O + D was found to be about 20 times smaller than that of pure DME + D. This provides the first evidence that the presence of solid water has a negative catalytic effect on tunneling H-abstraction reactions.

  9. Hydrogen negative ion production in a 14 GHz electron cyclotron resonance compact ion source with a cone-shaped magnetic filter.

    PubMed

    Ichikawa, T; Kasuya, T; Kenmotsu, T; Maeno, S; Nishiura, M; Shimozuma, T; Yamaoka, H; Wada, M

    2014-02-01

    The plasma electrode structure of a 14 GHz ECR ion source was modified to enlarge the plasma volume of low electron temperature region. The result shows that the extracted beam current reached about 0.6 mA/cm(2) with about 40 W microwave power. To investigate the correlation between the volume of the low electron temperature region and the H(-) current, a vacuum ultraviolet (VUV) spectrometer had been installed to observe light emission in the VUV wavelength range from the plasma. From the results of the negative ion beam current and that from VUV spectrometry, production rate of vibrationally excited hydrogen molecule seems to be enhanced by increasing the volume of low electron temperature region.

  10. Development of the front end test stand and vessel for extraction and source plasma analyses negative hydrogen ion sources at the Rutherford Appleton Laboratory

    SciTech Connect

    Lawrie, S. R.; Faircloth, D. C.; Letchford, A. P.; Perkins, M.; Whitehead, M. O.; Wood, T.; Gabor, C.; Back, J.

    2014-02-15

    The ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK uses a Penning surface plasma negative hydrogen ion source. Upgrade options for the ISIS accelerator system demand a higher current, lower emittance beam with longer pulse lengths from the injector. The Front End Test Stand is being constructed at RAL to meet the upgrade requirements using a modified ISIS ion source. A new 10% duty cycle 25 kV pulsed extraction power supply has been commissioned and the first meter of 3 MeV radio frequency quadrupole has been delivered. Simultaneously, a Vessel for Extraction and Source Plasma Analyses is under construction in a new laboratory at RAL. The detailed measurements of the plasma and extracted beam characteristics will allow a radical overhaul of the transport optics, potentially yielding a simpler source configuration with greater output and lifetime.

  11. An experimental study of waveguide coupled microwave heating with conventional multicusp negative ion sources

    NASA Astrophysics Data System (ADS)

    Komppula, J.; Kalvas, T.; Koivisto, H.; Laulainen, J.; Tarvainen, O.

    2015-04-01

    Negative ion production with conventional multicusp plasma chambers utilizing 2.45 GHz microwave heating is demonstrated. The experimental results were obtained with the multicusp plasma chambers and extraction systems of the RF-driven RADIS ion source and the filament driven arc discharge ion source LIISA. A waveguide microwave coupling system, which is almost similar to the one used with the SILHI ion source, was used. The results demonstrate that at least one third of negative ion beam obtained with inductive RF-coupling (RADIS) or arc discharge (LIISA) can be achieved with 1 kW of 2.45 GHz microwave power in CW mode without any modification of the plasma chamber. The co-extracted electron to H- ratio and the optimum pressure range were observed to be similar for both heating methods. The behaviour of the plasma implies that the energy transfer from the microwaves to the plasma electrons is mainly an off-resonance process.

  12. Negative ion source with external RF antenna

    DOEpatents

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

    2007-02-13

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  13. Influence of electrolyte composition and temperature on behaviour of AB5 hydrogen storage alloy used as negative electrode in Ni-MH batteries

    NASA Astrophysics Data System (ADS)

    Karwowska, Malgorzata; Jaron, Tomasz; Fijalkowski, Karol J.; Leszczynski, Piotr J.; Rogulski, Zbigniew; Czerwinski, Andrzej

    2014-10-01

    The AB5-type metal alloy (Mm-Ni4.1Al0.2Mn0.4Co0.45) has been investigated in different electrolytes (LiOH, NaOH, KOH, RbOH, CsOH). All of the electrochemical measurements have been performed using limited volume electrode technique (LVE). Thickness of the working electrode is nearly equal to the diameter of the grain (ca. 50 μm). Hydrogen diffusion coefficient has been determined using chronoamperometry. Hydrogen diffusion coefficient calculated for 100% state of charge reaches maximum value in KOH (DH = 4.65·10-10 cm2 s-1). We have obtained the highest value of capacity for the electrode in KOH and the lowest - in CsOH. The temperature influence on alloy capacity has been also tested. The alloy has been also characterised with SEM coupled with EDS, TGA/DSC and powder XRD. The unit cell of MmNi4.1Al0.2Mn0.4Co0.45 have been refined in the Cu5.4Yb0.8 structure type (a modified LaNi5 structure); the structure is unaffected by the electrochemical treatment.

  14. 3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

  15. Sensitivity of RF-driven Plasma Filaments to Trace Gases

    NASA Astrophysics Data System (ADS)

    Burin, M. J.; Czarnocki, C. J.; Czarnocki, K.; Zweben, S. J.; Zwicker, A.

    2011-10-01

    Filamentary structures have been observed in many types of plasma discharges in both natural (e.g. lightning) and industrial systems (e.g. dielectric barrier discharges). Recent progress has been made in characterizing these structures, though various aspects of their essential physics remain unclear. A common example of this phenomenon can be found within a toy plasma globe (or plasma ball), wherein a primarily neon gas mixture near atmospheric pressure clearly and aesthetically displays filamentation. Recent work has provided the first characterization of these plasma globe filaments [Campanell et al., Physics of Plasmas 2010], where it was noticed that discharges of pure gases tend not to produce filaments. We have extended this initial work to investigate in greater detail the dependence of trace gases on filamentation within a primarily Neon discharge. Our preliminary results using a custom globe apparatus will be presented, along with some discussion of voltage dependencies. Newly supported by the NSF/DOE Partnership in Basic Plasma Science and Engineering.

  16. The Effects of Negative Differential Resistance, Bipolar Spin-Filtering, and Spin-Rectifying on Step-Like Zigzag Graphene Nanoribbons Heterojunctions with Single or Double Edge-Saturated Hydrogen

    NASA Astrophysics Data System (ADS)

    Wang, Lihua; Zhao, Jianguo; Ding, Bingjun; Guo, Yong

    2016-09-01

    In this study, we investigated the spin-resolved transport aspects of step-like zigzag graphene ribbons (ZGNRs) with single or double edge-saturated hydrogen using a method that combined the density functional theory with the nonequilibrium Green's function method under the local spin density approximation. We found that, when the ZGNR-based heterojunctions were in a parallel or antiparallel layout, negative differential resistance, the maximum bipolar spin-filtering, and spin-rectifying effects occurred synchronously except for the case of spin-down electrons in the parallel magnetic layouts. Interestingly, these spin-resolved transport properties were almost unaffected by altering the widths of the two component ribbons. Therefore, step-like ZGNR heterojunctions are promising for use in designing high-performance multifunctional spintronic devices.

  17. Nitrogen Fixation and Hydrogen Metabolism in Relation to the Dissolved Oxygen Tension in Chemostat Cultures of the Wild Type and a Hydrogenase-Negative Mutant of Azorhizobium caulinodans

    PubMed Central

    Boogerd, Fred C.; Ferdinandy-van Vlerken, Marijke M. A.; Mawadza, Crispen; Pronk, Annemieke F.; Stouthamer, Adriaan H.; van Verseveld, Henk W.

    1994-01-01

    Both the wild type and an isogenic hydrogenase-negative mutant of Azorhizobium caulinodans growing ex planta on N2 as the N source were studied in succinate-limited steady-state chemostat cultures under 0.2 to 3.0% dissolved O2 tension. Production or consumption of O2, H2, and CO2 was measured with an on-line-connected mass spectrometer. In the range of 0.2 to 3.0%, growth of both the wild type and the mutant was equally dependent on the dissolved O2 tension: the growth yield decreased, and the specific O2 consumption and CO2 production increased. A similar dependency on the dissolved O2 tension was found for the mutant with 2.5% H2 in the influent gas. The H2/N2 ratio (moles of H2 evolved per mole of N2 consumed via nitrogenase) of the mutant, growing with or without 2.5% H2, increased with increasing dissolved O2 tensions. This increase in the H2/N2 ratio was small but significant. The dependencies of the ATP/N2 ratio (moles of ATP consumed per mole of N2 fixed) and the ATP/2e- ratio [moles of ATP consumed per mole of electron pairs transferred from NAD(P)H to nitrogenase] on the dissolved O2 tension were estimated. These dependencies were interpreted in terms of the physiological concepts of respiratory protection and autoprotection. PMID:16349280

  18. Negative Electron Affinity Mechanism for Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.

    1998-01-01

    The energy distribution of the secondary electrons for chemical vacuum deposited diamond films with Negative Electron Affinity (NEA) was investigated. It was found that while for completely hydrogenated diamond surfaces the negative electron affinity peak in the energy spectrum of the secondary electrons is present for any energy of the primary electrons, for partially hydrogenated diamond surfaces there is a critical energy above which the peak is present in the spectrum. This critical energy increases sharply when hydrogen coverage of the diamond surface diminishes. This effect was explained by the change of the NEA from the true type for the completely hydrogenated surface to the effective type for the partially hydrogenated surfaces.

  19. Cesium in hydrogen negative-ion sources

    SciTech Connect

    Belchenko, Yu.I.; Davydenko, V.I.

    2006-03-15

    Experimental data on the dynamics of cesium particles in the pulsed magnetron and Penning surface-plasma ion sources are presented. Cesium escape from the source emission apertures and the cesium ion current to discharge electrodes was measured. The low value of cesium flux from the source was detected. An intense cesium ion current to the cathode (up to 0.8 A/cm{sup 2}) was measured. The high value of cesium ion current to surface-plasma source cathode confirms the cesium circulation near the cathode.

  20. Negative hydrogen ion sources for accelerators

    SciTech Connect

    Moehs, D.P.; Peters, J.; Sherman, J.; /Los Alamos

    2005-08-01

    A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.

  1. Improvements of the magnetic field design for SPIDER and MITICA negative ion beam sources

    SciTech Connect

    Chitarin, G.; Agostinetti, P.; Aprile, D.; Marconato, N.; Veltri, P.

    2015-04-08

    The design of the magnetic field configuration in the SPIDER and MITICA negative ion beam sources has evolved considerably during the past four years. This evolution was driven by three factors: 1) the experimental results of the large RF-driven ion sources at IPP, which have provided valuable indications on the optimal magnetic configurations for reliable RF plasma source operation and for large negative ion current extraction, 2) the comprehensive beam optics and heat load simulations, which showed that the magnetic field configuration in the accelerator is crucial for keeping the heat load due to electrons on the accelerator grids within tolerable limits, without compromising the optics of the negative ion beam in the foreseen operating scenarios, 3) the progress of the detailed mechanical design of the accelerator, which stimulated the evaluation of different solutions for the correction of beamlet deflections of various origin and for beamlet aiming. On this basis, new requirements and solution concepts for the magnetic field configuration in the SPIDER and MITICA beam sources have been progressively introduced and updated until the design converged. The paper presents how these concepts have been integrated into a final design solution based on a horizontal “long-range” field (few mT) in combination with a “local” vertical field of some tens of mT on the acceleration grids.

  2. An experimental study of waveguide coupled microwave heating with conventional multicusp negative ion sources

    SciTech Connect

    Komppula, J.; Kalvas, T.; Koivisto, H.; Laulainen, J.; Tarvainen, O.

    2015-04-08

    Negative ion production with conventional multicusp plasma chambers utilizing 2.45 GHz microwave heating is demonstrated. The experimental results were obtained with the multicusp plasma chambers and extraction systems of the RF-driven RADIS ion source and the filament driven arc discharge ion source LIISA. A waveguide microwave coupling system, which is almost similar to the one used with the SILHI ion source, was used. The results demonstrate that at least one third of negative ion beam obtained with inductive RF-coupling (RADIS) or arc discharge (LIISA) can be achieved with 1 kW of 2.45 GHz microwave power in CW mode without any modification of the plasma chamber. The co-extracted electron to H{sup −} ratio and the optimum pressure range were observed to be similar for both heating methods. The behaviour of the plasma implies that the energy transfer from the microwaves to the plasma electrons is mainly an off-resonance process.

  3. Hydrogen sensor

    DOEpatents

    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.

  4. A Hydrogen Utopia?

    SciTech Connect

    Cherry, Robert Stephen; Reynolds, Bruce Allen

    2004-01-01

    The use of hydrogen as a fuel for transportation and stationary applications is receiving much favorable attention as a technical and policy issue. However, the widespread introduction of this technology is likely also to have negative consequences that are not being actively discussed in broad public forums. Such possibilities include, among others, delayed development of other energy alternatives, hazards of catalyst or hydride metals, disruptive employment shifts, land usage conflicts, and increased vehicle usage. Even though hydrogen is likely to be beneficial in its overall societal and environmental effects, hydrogen technology advocates must understand the range of problematic issues and prepare to address them.

  5. Negative necrotaxis.

    PubMed

    Ragot, R

    1993-01-01

    We studied necrotaxis in several strains of protists and compared the reaction of living cells in the vicinity of cells killed by a ruby laser. Negative necrotaxis was observed for the unicellular green alga Euglena gracilis, whereas Chlamydomonas was shown to exhibit positive necrotaxis. The cellular colony Pandorina morum exhibited no reaction to the killing of nearby colonies. Both the colorless cryptomonad Chilomonas paramecium and the ciliate Tetrahymena pyriformis exhibited negative necrotaxis following the lysis of vitally stained specimens of their own species. They also exhibited negative necrotaxis following the lysis of Euglena cells. It was also demonstrated that the cellular content of Euglena cells lysed by heat or by a mechanical procedure acts as a repellent to intact Euglena cells. These results suggest that the negative necrotaxis provoked in Euglena by the laser irradiation is probably due to the chemotactic effect produced by the release of cell content in the extracellular medium. This cell content could, according to its chemical composition, act either as a repellent, an attractant, or be inactive. The sensitivity of cells (specific or nonspecific ion channels or chemoreceptors) are also of prime importance in the process.

  6. Hydrogen trapping and the interaction of hydrogen with metals

    NASA Technical Reports Server (NTRS)

    Danford, Merlin D.

    1987-01-01

    A method has been developed for the determination of trapped hydrogen in metal alloys, involving the determination of mobile hydrogen using the electrochemical method and the determination of total hydrogen with the fusion method, the difference in hydrogen concentrations being due to trapped hydrogen. It has been found that hydrogen enters body-centered cubic structures through the grain bodies rather than through the grain boundaries. Hydrogen also diffuses much more rapidly in body-centered cubic structures on charging than in face-centered cubic structures, the hydrogen distribution being more uniform in nature. The energy necessary to cause hydrogen embrittlement is postulated to arise from the changes in crystal lattice energies brought about through interaction of hydrogen with atoms in the metal lattice. The total energy change is more negative for body-centered cubic structures, believed to be the cause of a greater tendency toward hydrogen embrittlement. Finally, the agreement of hydrogen concentrations obtained at 25 C by the electrochemical method with those obtained by the fusion method are taken as a strong indication of the power and validity of the electrochemical method.

  7. Hydrogen Production

    SciTech Connect

    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.

  8. Hydrogen Spectrum

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The series of absorption or emission lines that are characteristic of the hydrogen atom. According to the Bohr theory of the hydrogen atom, devised by Danish physicist Neils Bohr (1885-1962) in 1913, the hydrogen atom can be envisaged as consisting of a central nucleus (a proton) around which a single electron revolves. The electron is located in one of a number of possible permitted orbits, each...

  9. Coal hydrogenation

    SciTech Connect

    Sinor, J.E.

    1981-01-06

    Disclosure is made of a method and apparatus for reacting carbonaceous material such as pulverized coal with heated hydrogen to form hydrocarbon gases and liquids suitable for conversion to fuels wherein the reaction involves injection of pulverized coal entrained in a minimum amount of gas and mixing the entrained coal at ambient temperature with a separate source of heated hydrogen. The heated hydrogen and entrained coal are injected through a rocket engine type injector device. The coal particles are reacted with hydrogen in a reaction chamber downstream of the injector. The products of reaction are rapidly quenched as they exit the reaction chamber and are subsequently collected.

  10. Hydrogen Bibliography

    SciTech Connect

    Not Available

    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.

  11. Hydrogen energy.

    PubMed

    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.

  12. Hydrogen Effect against Hydrogen Embrittlement

    NASA Astrophysics Data System (ADS)

    Murakami, Yukitaka; Kanezaki, Toshihiko; Mine, Yoji

    2010-10-01

    The well-known term “hydrogen embrittlement” (HE) expresses undesirable effects due to hydrogen such as loss of ductility, decreased fracture toughness, and degradation of fatigue properties of metals. However, this article shows, surprisingly, that hydrogen can have an effect against HE. A dramatic phenomenon was found in which charging a supersaturated level of hydrogen into specimens of austenitic stainless steels of types 304 and 316L drastically improved the fatigue crack growth resistance, rather than accelerating fatigue crack growth rates. Although this mysterious phenomenon has not previously been observed in the history of HE research, its mechanism can be understood as an interaction between hydrogen and dislocations. Hydrogen can play two roles in terms of dislocation mobility: pinning (or dragging) and enhancement of mobility. Competition between these two roles determines whether the resulting phenomenon is damaging or, unexpectedly, desirable. This finding will, not only be the crucial key factor to elucidate the mechanism of HE, but also be a trigger to review all existing theories on HE in which hydrogen is regarded as a dangerous culprit.

  13. Storing Hydrogen

    SciTech Connect

    Kim, Hyun Jeong; Karkamkar, Abhijeet J.; Autrey, Thomas; Chupas, Peter; Proffen, Thomas E.

    2010-05-31

    Researchers have been studying mesoporous materials for almost two decades with a view to using them as hosts for small molecules and scaffolds for molding organic compounds into new hybrid materials and nanoparticles. Their use as potential storage systems for large quantities of hydrogen has also been mooted. Such systems that might hold large quantities of hydrogen safely and in a very compact volume would have enormous potential for powering fuel cell vehicles, for instance. A sponge-like form of silicon dioxide, the stuff of sand particles and computer chips, can soak up and store other compounds including hydrogen. Studies carried out at the XOR/BESSRC 11-ID-B beamline at the APS have revealed that the nanoscopic properties of the hydrogenrich compound ammonia borane help it store hydrogen more efficiently than usual. The material may have potential for addressing the storage issues associated with a future hydrogen economy. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  14. Cesium injection system for negative ion duoplasmatrons

    DOEpatents

    Kobayashi, Maasaki; Prelec, Krsto; Sluyters, Theodorus J

    1978-01-01

    Longitudinally extending, foraminous cartridge means having a cylindrical side wall forming one flat, circular, tip end surface and an opposite end; an open-ended cavity, and uniformly spaced orifices for venting the cavity through the side wall in the annulus of a plasma ring for uniformly ejecting cesium for coating the flat, circular, surface. To this end, the cavity is filled with a cesium containing substance and attached to a heater in a hollow-discharge duoplasmatron. By coating the flat circular surface with a uniform monolayer of cesium and locating it in an electrical potential well at the end of a hollow-discharge, ion duoplasmatron source of an annular hydrogen plasma ring, the negative hydrogen production from the duoplasmatron is increased. The negative hydrogen is produced on the flat surface of the cartridge and extracted by the electrical potential well along a trajectory coaxial with the axis of the plasma ring.

  15. Hydrogen bonded arrays: the power of multiple hydrogen bonds.

    PubMed

    Shokri, Alireza; Schmidt, Jacob; Wang, Xue-Bin; Kass, Steven R

    2012-02-01

    Hydrogen bond interactions in small covalent model compounds (i.e., deprotonated polyhydroxy alcohols) were measured by negative ion photoelectron spectroscopy. The experimentally determined vertical and adiabatic electron detachment energies for (HOCH(2)CH(2))(2)CHO(-)(2a), (HOCH(2)CH(2))(3)CO(-) (3a), and (HOCH(2)CH(2)CH(OH)CH(2))(3)CO(-) (4a)reveal that hydrogen-bonded networks can provide enormous stabilizations and that a single charge center not only can be stabilized by up to three hydrogen bonds but also can increase the interaction energy between noncharged OH groups by 5.8 kcal mol(-1) or more per hydrogen bond. This can lead to pK(a) values that are very different from those in water and can provide some of the impetus for catalytic processes.

  16. Hydrogen program overview

    SciTech Connect

    Gronich, S.

    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.

  17. Meningitis - gram-negative

    MedlinePlus

    Gram-negative meningitis ... Acute bacterial meningitis can be caused by Gram-negative bacteria. Meningococcal and H. influenzae meningitis are caused by Gram-negative bacteria and are covered in detail in other articles. This article ...

  18. Hydrogen sulfide

    Integrated Risk Information System (IRIS)

    Hydrogen sulfide ; 7783 - 06 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  19. Hydrogen chloride

    Integrated Risk Information System (IRIS)

    Hydrogen chloride ; CASRN 7647 - 01 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  20. Hydrogen technologies

    SciTech Connect

    Not Available

    1992-05-01

    To the non-nonsense engineer, any talk of a hydrogen economy may seem like so much hot air. This paper reports that as legislative, safety and environmental issues continue to tighten, they're promoting hydrogen's chances as an energy source and, more immediately, its prospects as a chemical feedstock. Paradoxically, the environmental demands that are stimulating hydrogen demand are also inhibiting the gas's production. Previously, gasoline was made with benzene, which means that H{sub 2} was rejected. But now that the laws mandate lower aromatic and higher oxygenate levels in gasolines, there's less H{sub 2} available as byproduct. At the same time, H{sub 2} demand is rising in hydrodesulfurization units, since the same laws require refiners to cut sulfur levels in fuels. Supplementary sources for the gas are also shrinking. In the chlor-alkali industry, H{sub 2} output is dropping, as demand for its coproduct chlorine weakens. At the same time, H{sub 2} demand for the making of hydrogen peroxide is growing, as that environmentally safer bleach gains chlorine's market share.

  1. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  2. Electrochemical Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  3. Hydrogen scavengers

    SciTech Connect

    Carroll, David W.; Salazar, Kenneth V.; Trkula, Mitchell; Sandoval, Cynthia W.

    2002-01-01

    There has been invented a codeposition process for fabricating hydrogen scavengers. First, a .pi.-bonded allylic organometallic complex is prepared by reacting an allylic transition metal halide with an organic ligand complexed with an alkali metal; and then, in a second step, a vapor of the .pi.-bonded allylic organometallic complex is combined with the vapor of an acetylenic compound, irradiated with UV light, and codeposited on a substrate.

  4. Volume production of negative ions in the reflex-type ion source

    SciTech Connect

    Jimbo, K.

    1982-06-01

    The production of negative hydrogen ions is investigated in the reflex-type negative ion source. The extracted negative hydrogen currents of 9.7 mA (100 mA/cm/sup 2/) for H/sup -/ and of 4.1 mA(42 mA/cm/sup 2/) for D/sup -/ are obtained continuously. The impurity is less than 1%. An isotope effect of negative ion production is observed.

  5. Hydrogen environment embrittlement

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effect of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed. Additional research is required to determine whether hydrogen environment embrittlement and internal reversible hydrogen embrittlement are similar or distinct types of embrittlement.

  6. RF driven sulfur lamp having driving electrodes which face each other

    DOEpatents

    Gabor, George; Orr, Thomas Robert; Greene, Charles Maurice; Crawford, Douglas Gordon; Berman, Samuel Maurice

    1999-01-01

    A high intensity discharge lamp without mercury is disclosed radiating a selected spectrum of which can be almost entirely in the visible range from an envelope that contains a sulfur containing substance. The lamp utilizes a signal source that generates an excitation signal that is externally coupled to the exterior surface of the envelope to excite the enclosed sulfur containing substance. Various embodiments of the lamp use electrodes adjacent the envelope to couple the excitation signal thereto with the face of the electrodes shaped to complement the shape of the exterior surface of the envelope. Two shapes discussed are spherical and cylindrical. To minimize filamentary discharges each envelope may include an elongated stem affixed to the exterior thereof whereby a rotational subsystem spins the envelope. In yet another embodiment the envelope has a Dewar configuration with two electrodes, one positioned near the external curved side surface of the body, and a second to the inner surface of the hole through the envelope. Further, the envelope may contain a backfill of a selected inert gas to assist in the excitation of lamp with that backfill at a pressure of less than 1 atmosphere, wherein the backfill pressure is directly related to the increase or decrease of peak output and inversely related to the increase and decrease of the emitted spectrum from the envelope. The emitting fill can be less than 6 mg/cc, or at least 2 mg/cc of the envelope of a sulfur containing substance.

  7. RF driven sulfur lamp having driving electrodes which face each other

    DOEpatents

    Gabor, G.; Orr, T.R.; Greene, C.M.; Crawford, D.G.; Berman, S.M.

    1999-06-22

    A high intensity discharge lamp without mercury is disclosed radiating a selected spectrum of which can be almost entirely in the visible range from an envelope that contains a sulfur containing substance. The lamp utilizes a signal source that generates an excitation signal that is externally coupled to the exterior surface of the envelope to excite the enclosed sulfur containing substance. Various embodiments of the lamp use electrodes adjacent the envelope to couple the excitation signal thereto with the face of the electrodes shaped to complement the shape of the exterior surface of the envelope. Two shapes discussed are spherical and cylindrical. To minimize filamentary discharges each envelope may include an elongated stem affixed to the exterior thereof whereby a rotational subsystem spins the envelope. In yet another embodiment the envelope has a Dewar configuration with two electrodes, one positioned near the external curved side surface of the body, and a second to the inner surface of the hole through the envelope. Further, the envelope may contain a backfill of a selected inert gas to assist in the excitation of lamp with that backfill at a pressure of less than 1 atmosphere, wherein the backfill pressure is directly related to the increase or decrease of peak output and inversely related to the increase and decrease of the emitted spectrum from the envelope. The emitting fill can be less than 6 mg/cc, or at least 2 mg/cc of the envelope of a sulfur containing substance. 17 figs.

  8. RF driven sulfur lamp having driving electrodes arranged to cool the lamp

    DOEpatents

    Gabor, G.; Orr, T.R.; Greene, C.M.; Crawford, D.G.; Berman, S.M.

    1998-10-20

    A high intensity discharge lamp without mercury is disclosed radiating a selected spectrum of which can be almost entirely in the visible range from an envelope that contains a sulfur containing substance. The lamp utilizes a signal source that generates an excitation signal that is externally coupled to the exterior surface of the envelope to excite the enclosed sulfur containing substance. Various embodiments of the lamp use electrodes adjacent the envelope to couple the excitation signal thereto with the face of the electrodes shaped to complement the shape of the exterior surface of the envelope. Two shapes discussed are spherical and cylindrical. To minimize filamentary discharges each envelope may include an elongated stem affixed to the exterior thereof whereby a rotational subsystem spins the envelope. In yet another embodiment the envelope has a Dewar configuration with two electrodes, one positioned near the external curved side surface of the body, and a second to the inner surface of the hole through the envelope. Further, the envelope may contain a backfill of a selected inert gas to assist in the excitation of lamp with that backfill at a pressure of less than 1 atmosphere, wherein the backfill pressure is directly related to the increase or decrease of peak output and inversely related to the increase and decrease of the emitted spectrum from the envelope. The emitting fill can be less than 6 mg/cc, or at least 2 mg/cc of the envelope of a sulfur containing substance. 17 figs.

  9. RF driven sulfur lamp having driving electrodes arranged to cool the lamp

    DOEpatents

    Gabor, George; Orr, Thomas Robert; Greene, Charles Maurice; Crawford, Douglas Gordon; Berman, Samuel Maurice

    1998-01-01

    A high intensity discharge lamp without mercury is disclosed radiating a selected spectrum of which can be almost entirely in the visible range from an envelope that contains a sulfur containing substance. The lamp utilizes a signal source that generates an excitation signal that is externally coupled to the exterior surface of the envelope to excite the enclosed sulfur containing substance. Various embodiments of the lamp use electrodes adjacent the envelope to couple the excitation signal thereto with the face of the electrodes shaped to complement the shape of the exterior surface of the envelope. Two shapes discussed are spherical and cylindrical. To minimize filamentary discharges each envelope may include an elongated stem affixed to the exterior thereof whereby a rotational subsystem spins the envelope. In yet another embodiment the envelope has a Dewar configuration with two electrodes, one positioned near the external curved side surface of the body, and a second to the inner surface of the hole through the envelope. Further, the envelope may contain a backfill of a selected inert gas to assist in the excitation of lamp with that backfill at a pressure of less than 1 atmosphere, wherein the backfill pressure is directly related to the increase or decrease of peak output and inversely related to the increase and decrease of the emitted spectrum from the envelope. The emitting fill can be less than 6 mg/cc, or at least 2 mg/cc of the envelope of a sulfur containing substance.

  10. RF-driven tokamak reactor with sub-ignited, thermally stable operation

    SciTech Connect

    Harten, L.P.; Bers, A.; Fuchs, V.; Shoucri, M.M.

    1981-02-01

    A Radio-Frequency Driven Tokamak Reactor (RFDTR) can use RF-power, programmed by a delayed temperature measurement, to thermally stabilize a power equilibrium below ignition, and to drive a steady state current. We propose the parameters for such a device generating approx. = 1600 MW thermal power and operating with Q approx. = 40 (= power out/power in). A one temperature zero-dimensional model allows simple analytical formulation of the problem. The relevance of injected impurities for locating the equilibrium is discussed. We present the results of a one-dimensional (radial) code which includes the deposition of the supplementary power, and compare with our zero-dimensional model.

  11. RUI: Structure and Behavior of RF-Driven Plasma Filaments in High-Pressure Gases

    SciTech Connect

    Burin, Michael J.

    2014-11-18

    The filamentary discharge seen within commercial plasma globes is commonly enjoyed, yet not well understood. We investigate filament properties in a plasma globe using a variable high voltage amplifier. Results from the 3-year grant period and their physics are discussed.

  12. The injection of microorganisms into an atmospheric pressure rf-driven microplasma

    NASA Astrophysics Data System (ADS)

    Maguire, P. D.; Mahony, C. M. O.; Diver, D.; Mariotti, D.; Bennet, E.; Potts, H.; McDowell, D. A.

    2013-09-01

    The introduction of living organisms, such as bacteria, into atmospheric pressure microplasmas offers a unique means to study certain physical mechanisms in individual microorganisms and also help understand the impact of macroscopic entities and liquid droplets on plasma characteristics. We present the characterization of an RF-APD operating at 13.56 MHz and containing microorganisms in liquid droplets emitted from a nebulizer, with the spray entrained in a gas flow by a gas shroud and passed into the plasma source. We report successful microorganism injection and transmission through the plasma with stable plasma operation of at least one hour. Diagnostics include RF electrical characterization, optical emission spectrometry and electrostatic deflection to investigate microorganism charging. A close-coupled Impedans Octiv VI probe indicates source efficiencies of 10 to 15%. The introduction of the droplets/microorganisms results in increased plasma conductivity and reduced capacitance, due to their impact on electron density and temperature. An electrical model will be presented based on diagnostic data and deflection studies with input from simulations of charged aerosol diffusion and evaporation. Engineering and Physical Sciences Research Council EP/K006088, EP/K006142.

  13. X-band dielectric loaded RF driven accelerator structures: Theoretical and experimental investigations

    NASA Astrophysics Data System (ADS)

    Zou, Peng

    An important area of application of high-power radio frequency (RF) and microwave sources is particle acceleration. A major challenge for the current worldwide research and development effort in linear accelerator is the search for a compact and affordable very-high-energy accelerator technology for the next generation supercolliders. It has been recognized for sometime that dielectric loaded accelerator structures are attractive candidates for the next generation very-high-energy linear accelerators, because they possess several distinct advantages over conventional metallic iris- loaded accelerator structures. However, some fundamental issues, such as RF breakdown in the dielectric, Joule heating, and vacuum properties of dielectric materials, are still the subjects of intense investigation, requiring the validation by experiments conducted at high power levels. An X-band traveling-wave accelerator based on dielectric-lined waveguide has been designed and constructed. Numerical calculation, bench measurements, and 3-D electromagnetic field simulation of this dielectric loaded accelerator are presented. One critical technical problem in constructing such dielectric loaded accelerator is efficient coupling of RF power into the dielectric-lined circular waveguide. A coupling scheme has been arrived at by empirical methods. Field distribution in this coupling configuration has been studied by numerical simulation. In the conventional iris-loaded accelerator structures, the peak surface electric field E s is in general found to be at least a factor of 2 higher than the axial acceleration field Ea. Because the peak surface electric field causes electric breakdown of the structure, it represents a direct limitation on the maximum acceleration gradient that can be obtained. A novel hybrid dielectric-iris-loaded periodic accelerator structure is proposed to utilize the advantages of both dielectric-lined waveguides and conventional iris-loaded structures. Numerical simulations show that this type of hybrid accelerator structure can reduce the peak surface electric field on the iris by more than a factor of two without diminishing much in the shunt impedance and the quality factor. This research program addressed the fundamental issues and engineering challenges of dielectric-loaded accelerator structures. Dielectric loaded accelerator structures could be a promising alternative to the conventional designs.

  14. RF-driven ion source with a back-streaming electron dump

    DOEpatents

    Kwan, Joe; Ji, Qing

    2014-05-20

    A novel ion source is described having an improved lifetime. The ion source, in one embodiment, is a proton source, including an external RF antenna mounted to an RF window. To prevent backstreaming electrons formed in the beam column from striking the RF window, a back streaming electron dump is provided, which in one embodiment is formed of a cylindrical tube, open at one end to the ion source chamber and capped at its other end by a metal plug. The plug, maintained at the same electrical potential as the source, captures these backstreaming electrons, and thus prevents localized heating of the window, which due to said heating, might otherwise cause window damage.

  15. ADX: A high Power Density, Advanced RF-Driven Divertor Test Tokamak for PMI studies

    NASA Astrophysics Data System (ADS)

    Whyte, Dennis; ADX Team

    2015-11-01

    The MIT PSFC and collaborators are proposing an advanced divertor experiment, ADX; a divertor test tokamak dedicated to address critical gaps in plasma-material interactions (PMI) science, and the world fusion research program, on the pathway to FNSF/DEMO. Basic ADX design features are motivated and discussed. In order to assess the widest range of advanced divertor concepts, a large fraction (>50%) of the toroidal field volume is purpose-built with innovative magnetic topology control and flexibility for assessing different surfaces, including liquids. ADX features high B-field (>6 Tesla) and high global power density (P/S ~ 1.5 MW/m2) in order to access the full range of parallel heat flux and divertor plasma pressures foreseen for reactors, while simultaneously assessing the effect of highly dissipative divertors on core plasma/pedestal. Various options for efficiently achieving high field are being assessed including the use of Alcator technology (cryogenic cooled copper) and high-temperature superconductors. The experimental platform would also explore advanced lower hybrid current drive and ion-cyclotron range of frequency actuators located at the high-field side; a location which is predicted to greatly reduce the PMI effects on the launcher while minimally perturbing the core plasma. The synergistic effects of high-field launchers with high total B on current and flow drive can thus be studied in reactor-relevant boundary plasmas.

  16. Electrical and Optical Measurements in an RF-Driven Micro-Discharge Source

    NASA Astrophysics Data System (ADS)

    Mahony, C. M. O.; Gans, T.; Graham, W. G.; Maguire, P. D.; Petrovic, Z. Lj.

    2007-10-01

    Microdischarge properties are distinctly different to those of larger sources, leading to potential applications such as: high density tailored plasmas, local heating, fast material processing and scale up to large area sources. Hollow cathode operation is unlikely in micro-hollow cathode devices of diameter <= 100 μm^[1] because short mean free paths inhibit pendular electron motion. Thus diameters as small as 10 μm may be required for HC operation, a critical stability challenge. We report radio frequency operation in micro-hollow cathode structures for diameters as small as 25μm. The sources are operated in argon and helium at pressures of 20 to 600 Torr and ignite readily at ˜20 W, operating stably at powers <10W. Measurements of breakdown characteristics, rf current and voltage and optical emission were recorded. A number of operating modes have been observed in these sub-100μm dimensions and OES of argon and helium discharges indicates there is less sputtering with helium. Positive dc bias has been observed in the cathode potential under rf operation, similar to that reported by Guo & Hong^[2] at a diameter of 300 μm. [1] Kushner, J. Phys. D: Appl. Phys. 38 (2005) 1633 [2]Guo & Hong, Jpn. J. Appl. Phys. 42 (2003) 6598

  17. Negative ion generator

    DOEpatents

    Stinnett, Regan W.

    1984-01-01

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions.

  18. Negative ion generator

    DOEpatents

    Stinnett, R.W.

    1984-05-08

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions. 8 figs.

  19. Sentential Negation in English

    ERIC Educational Resources Information Center

    Mowarin, Macaulay

    2009-01-01

    This paper undertakes a detailed analysis of sentential negation in the English language with Chomsky's Government-Binding theory of Transformational Grammar as theoretical model. It distinguishes between constituent and sentential negation in English. The essay identifies the exact position of Negation phrase in an English clause structure. It…

  20. Hydrogen detector

    DOEpatents

    Kanegae, Naomichi; Ikemoto, Ichiro

    1980-01-01

    A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

  1. Mechanochemical hydrogenation of coal

    DOEpatents

    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.

  2. Hydrogen peroxide poisoning

    MedlinePlus

    ... peroxide is used in these products: Hydrogen peroxide Hair bleach Some contact lens cleaners Note: Household hydrogen peroxide ... it contains 97% water and 3% hydrogen peroxide. Hair bleaches are stronger. They usually have a concentration of ...

  3. Negative Ion Density Fronts

    SciTech Connect

    Igor Kaganovich

    2000-12-18

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas.

  4. Negative Questions in Chinese

    ERIC Educational Resources Information Center

    Yat-shing, Cheung

    1974-01-01

    Mainly concerned with where negative questions in Chinese originate.An abstract treatment allows the derviation of all questions from a general underlying structure with disjunctive pattern and accounts for the discordance between the answer to a negative question and its answer particle. (Author/RM)

  5. RF Negative Ion Source Development at IPP Garching

    SciTech Connect

    Kraus, W.; McNeely, P.; Berger, M.; Christ-Koch, S.; Falter, H. D.; Fantz, U.; Franzen, P.; Froeschle, M.; Heinemann, B.; Leyer, S.; Riedl, R.; Speth, E.; Wuenderlich, D.

    2007-08-10

    IPP Garching is heavily involved in the development of an ion source for Neutral Beam Heating of the ITER Tokamak. RF driven ion sources have been successfully developed and are in operation on the ASDEX-Upgrade Tokamak for positive ion based NBH by the NB Heating group at IPP Garching. Building on this experience a RF driven H- ion source has been under development at IPP Garching as an alternative to the ITER reference design ion source. The number of test beds devoted to source development for ITER has increased from one (BATMAN) by the addition of two test beds (MANITU, RADI). This paper contains descriptions of the three test beds. Results on diagnostic development using laser photodetachment and cavity ringdown spectroscopy are given for BATMAN. The latest results for long pulse development on MANITU are presented including the to date longest pulse (600 s). As well, details of source modifications necessitated for pulses in excess of 100 s are given. The newest test bed RADI is still being commissioned and only technical details of the test bed are included in this paper. The final topic of the paper is an investigation into the effects of biasing the plasma grid.

  6. RF Negative Ion Source Development at IPP Garching

    NASA Astrophysics Data System (ADS)

    Kraus, W.; McNeely, P.; Berger, M.; Christ-Koch, S.; Falter, H. D.; Fantz, U.; Franzen, P.; Fröschle, M.; Heinemann, B.; Leyer, S.; Riedl, R.; Speth, E.; Wünderlich, D.

    2007-08-01

    IPP Garching is heavily involved in the development of an ion source for Neutral Beam Heating of the ITER Tokamak. RF driven ion sources have been successfully developed and are in operation on the ASDEX-Upgrade Tokamak for positive ion based NBH by the NB Heating group at IPP Garching. Building on this experience a RF driven H- ion source has been under development at IPP Garching as an alternative to the ITER reference design ion source. The number of test beds devoted to source development for ITER has increased from one (BATMAN) by the addition of two test beds (MANITU, RADI). This paper contains descriptions of the three test beds. Results on diagnostic development using laser photodetachment and cavity ringdown spectroscopy are given for BATMAN. The latest results for long pulse development on MANITU are presented including the to date longest pulse (600 s). As well, details of source modifications necessitated for pulses in excess of 100 s are given. The newest test bed RADI is still being commissioned and only technical details of the test bed are included in this paper. The final topic of the paper is an investigation into the effects of biasing the plasma grid.

  7. Tribology in Gaseous Hydrogen

    NASA Astrophysics Data System (ADS)

    Sawae, Yoshinori; Sugimura, Joich

    Hydrogen is expected as a clean and renewable energy carrier for future environment-friendly society. Many machine elements in hydrogen energy systems should be operating within hydrogen gas and tribological behavior, such as friction and wear, of bearings and seals are affected by the hydrogen environment through some interactions between material surfaces and gaseous hydrogen, i.e., physisorption of hydrogen molecules and following chemisorptions of dissociated atoms on metal surfaces, formation of metal hydride and reduction of metal oxide layer by hydrogen atoms diffused into bulk. Therefore, friction and wear characteristics of tribomaterials in the hydrogen environment should be appropriately understood to establish a design guideline for reliable hydrogen utilizing systems. This paper reviews the current knowledge about the effect of hydrogen on friction and wear of materials, and then describes our recent progress of hydrogen research in the tribology field.

  8. Evaluation of negative ion distribution changes by image processing diagnostic

    SciTech Connect

    Ikeda, K. Nakano, H.; Tsumori, K.; Kisaki, M.; Nagaoka, K.; Tokuzawa, T.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Geng, S.

    2015-04-08

    Distributions of hydrogen Balmer-α (H{sub α}) intensity and its reduction behavior close to a plasma grid (PG) surface have been observed by a spectrally selective imaging system in an arc discharge type negative hydrogen ion source in National Institute for Fusion Science. H{sub α} reduction indicates a reduction of negative hydrogen ions because the mutual neutralization process between H{sup +} and H{sup −} ions causes the dominant excitation process for H{sub α} emission in the rich H{sup −} condition such as in ionic plasma. We observed a significant change in H{sub α} reduction distribution due to change in the bias voltage, which is used to suppress the electron influx. Small H{sub α} reduction in higher bias is likely because the production of negative ions is suppressed by the potential difference between the plasma and PG surface.

  9. Kriging without negative weights

    SciTech Connect

    Szidarovszky, F.; Baafi, E.Y.; Kim, Y.C.

    1987-08-01

    Under a constant drift, the linear kriging estimator is considered as a weighted average of n available sample values. Kriging weights are determined such that the estimator is unbiased and optimal. To meet these requirements, negative kriging weights are sometimes found. Use of negative weights can produce negative block grades, which makes no practical sense. In some applications, all kriging weights may be required to be nonnegative. In this paper, a derivation of a set of nonlinear equations with the nonnegative constraint is presented. A numerical algorithm also is developed for the solution of the new set of kriging equations.

  10. Negative birefringent polyimide films

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor); Cheng, Stephen Z. D. (Inventor)

    1994-01-01

    A negative birefringent film, useful in liquid crystal displays, and a method for controlling the negative birefringence of a polyimide film is disclosed which allows the matching of an application to a targeted amount of birefringence by controlling the degree of in-plane orientation of the polyimide by the selection of functional groups within both the diamine and dianhydride segments of the polyimide which affect the polyimide backbone chain rigidity, linearity, and symmetry. The higher the rigidity, linearity and symmetry of the polyimide backbone, the larger the value of the negative birefringence of the polyimide film.

  11. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Enz, Glenn L.

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  12. Composition for absorbing hydrogen

    DOEpatents

    Heung, L.K.; Wicks, G.G.; Enz, G.L.

    1995-05-02

    A hydrogen absorbing composition is described. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  13. Negative electrode composition

    DOEpatents

    Kaun, Thomas D.; Chilenskas, Albert A.

    1982-01-01

    A secondary electrochemical cell and a negative electrode composition for use therewith comprising a positive electrode containing an active material of a chalcogen or a transiton metal chalcogenide, a negative electrode containing a lithium-aluminum alloy and an amount of a ternary alloy sufficient to provide at least about 5 percent overcharge capacity relative to a negative electrode solely of the lithium-aluminum alloy, the ternary alloy comprising lithium, aluminum, and iron or cobalt, and an electrolyte containing lithium ions in contact with both of the positive and the negative electrodes. The ternary alloy is present in the electrode in the range of from about 5 percent to about 50 percent by weight of the electrode composition and may include lithium-aluminum-nickel alloy in combination with either the ternary iron or cobalt alloys. A plurality of series connected cells having overcharge capacity can be equalized on the discharge side without expensive electrical equipment.

  14. Logo and Negative Numbers.

    ERIC Educational Resources Information Center

    Strawn, Candace A.

    1998-01-01

    Describes LOGO's turtle graphics capabilities based on a sixth-grade classroom's activities with negative numbers and Logo programming. A sidebar explains LOGO and offers suggestions to teachers for using LOGO effectively. (LRW)

  15. No to negative data

    SciTech Connect

    Wiley, H. S.

    2008-04-01

    A frequent criticism in biology is that we don’t publish our negative data. As a result, the literature has become biased towards papers that favor specific hypotheses1. Some scientists have become so concerned about this trend that they have created journals dedicated to publishing negative results (e.g. the Journal of Negative Results in Biomedicine). Personally, I don’t think they should bother. I say this because I believe negative results are not worth publishing. Rest assured that I do not include drug studies that show a lack of effectiveness towards a specific disease or condition. This type of finding is significant in a societal context, not a scientific one, and thus we all have a vested interest in seeing this type of result published. I am talking about a set of experimental results that fail to support a particular hypothesis. The problem with these types of negative results is that they don’t actually advance science. Science is a set of ideas that can be supported by observations. A negative result does not support any specific idea, but only tells you what isn’t right. Well, there are only a small number of potential hypotheses that are correct, but essentially an infinite number of ideas are not correct. I don’t want to waste my time reading a paper about what doesn’t happen, just about those things that do. I can remember a positive result because I can associate it with a specific concept. What do I do with a negative one? It is hard enough to following the current literature. A flood of negative results would make that task all but impossible

  16. Negative affixes in medical English.

    PubMed

    Dzuganova, B

    2006-01-01

    Many medical terms have negative meaning expressed by means of a negative prefix or suffix. The most frequently used negative prefixes are: a-, dis-, in-, non-, and un-. There is only one negative suffix -less (Ref. 15). PMID:17125069

  17. A Few Facts about Hydrogen [and] Hydrogen Bibliography.

    ERIC Educational Resources Information Center

    Hinds, H. Roger

    Divided into two sections, this publication presents facts about and the characteristics of hydrogen and a bibliography on hydrogen. The first section lists nine facts on what hydrogen is, four on where hydrogen is found, nine on how hydrogen is used, nine on how hydrogen can be used, and 14 on how hydrogen is made. Also included are nine…

  18. Physical applications of muon catalysis: Muon capture in hydrogen

    NASA Astrophysics Data System (ADS)

    Filchenkov, V. V.

    2016-07-01

    Results of theoretical and experimental research on capture of negative muons in hydrogen are reported with an emphasis on the accompanying phenomenon of muon catalysis in hydrogen and subtleties of the experimental method. A conclusion is drawn that precise determination of the capture rate is important for refining the standard model.

  19. Negative Halogen Ions for Fusion Applications

    SciTech Connect

    Grisham, L.R.; Kwan, J.W.; Hahto, S.K.; Hahto, S.T.; Leung, K.N.; Westenskow, G.

    2006-01-01

    Over the past quarter century, advances in hydrogen negative ion sources have extended the usable range of hydrogen isotope neutral beams to energies suitable for large magnetically confined fusion devices. Recently, drawing upon this experience, negative halogen ions have been proposed as an alternative to positive ions for heavy ion fusion drivers in inertial confinement fusion, because electron accumulation would be prevented in negative ion beams, and if desired, the beams could be photo-detached to neutrals. This paper reports the results of an experiment comparing the current density and beam emittance of Cl+ and Cl- extracted from substantially ion-ion plasmas with that of Ar+ extracted from an ordinary electron-ion plasma, all using the same source, extractor, and emittance scanner. At similar discharge conditions, the Cl- current was typically 85 – 90% of the positive chlorine current, with an e-/ Cl- ratio as low as seven without grid magnets. The Cl- was as much as 76% of the Ar+ current from a discharge with the same RF drive. The minimum normalized beam emittance and inferred ion temperatures of Cl+, Cl-, and Ar+ were all similar, so the current density and optical quality of Cl- appear as suitable for heavy ion fusion driver applications as a positive noble gas ion of similar mass. Since F, I, and Br should all behave similarly in an ion source, they should also be suitable as driver beams.

  20. Anxiety and feedback negativity.

    PubMed

    Gu, Ruolei; Huang, Yu-Xia; Luo, Yue-Jia

    2010-09-01

    It has been suggested that anxious individuals are more prone to feel that negative outcomes are particularly extreme and to interpret ambiguous outcomes as negative compared to nonanxious individuals. Previous studies have demonstrated that the feedback negativity (FN) component of event-related brain potential (ERP) is sensitive to outcome evaluation and outcome expectancy. Hence, we predicted that the FN should be different between high trait-anxiety (HTA) and low trait-anxiety (LTA) individuals. To test our hypothesis, the ERPs were recorded during a simple monetary gambling task. The FN was measured as a difference wave created across conditions. We found that the amplitude of the FN indicating negative versus positive outcomes was significantly larger for LTA individuals compared to HTA individuals. However, there was no significant difference in the FN between groups in response to ambiguous versus positive outcomes. The results indicate that there is a relationship between the FN and individual differences in anxiety. We suggest that these results reflect the impact of anxiety on outcome expectation. Our results challenge the reinforcement learning theory of error-related negativity, which proposes that ERN and FN reflect the same cognitive process.

  1. Charged particle flows in the beam extraction region of a negative ion source for NBI.

    PubMed

    Geng, S; Tsumori, K; Nakano, H; Kisaki, M; Ikeda, K; Osakabe, M; Nagaoka, K; Takeiri, Y; Shibuya, M; Kaneko, O

    2016-02-01

    Experiments by a four-pin probe and photodetachment technique were carried out to investigate the charged particle flows in the beam extraction region of a negative hydrogen ion source for neutral beam injector. Electron and positive ion flows were obtained from the polar distribution of the probe saturation current. Negative hydrogen ion flow velocity and temperature were obtained by comparing the recovery times of the photodetachment signals at opposite probe tips. Electron and positive ions flows are dominated by crossed field drift and ambipolar diffusion. Negative hydrogen ion temperature is evaluated to be 0.12 eV. PMID:26931985

  2. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Kreutz, T.G.; Steinbugler, M.

    1996-10-01

    In this report the authors describe results from technical and economic assessments carried out during the past year with support from the USDOE Hydrogen R&D Program. (1) Assessment of technologies for small scale production of hydrogen from natural gas. Because of the cost and logistics of transporting and storing hydrogen, it may be preferable to produce hydrogen at the point of use from more readily available energy carriers such as natural gas or electricity. In this task the authors assess near term technologies for producing hydrogen from natural gas at small scale including steam reforming, partial oxidation and autothermal reforming. (2) Case study of developing a hydrogen vehicle refueling infrastructure in Southern California. Many analysts suggest that the first widespread use of hydrogen energy is likely to be in zero emission vehicles in Southern California. Several hundred thousand zero emission automobiles are projected for the Los Angeles Basin alone by 2010, if mandated levels are implemented. Assuming that hydrogen vehicles capture a significant fraction of this market, a large demand for hydrogen fuel could evolve over the next few decades. Refueling a large number of hydrogen vehicles poses significant challenges. In this task the authors assess near term options for producing and delivering gaseous hydrogen transportation fuel to users in Southern California including: (1) hydrogen produced from natural gas in a large, centralized steam reforming plant, and delivered to refueling stations via liquid hydrogen truck or small scale hydrogen gas pipeline, (2) hydrogen produced at the refueling station via small scale steam reforming of natural gas, (3) hydrogen produced via small scale electrolysis at the refueling station, and (4) hydrogen from low cost chemical industry sources (e.g. excess capacity in refineries which have recently upgraded their hydrogen production capacity, etc.).

  3. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  4. Extracted current saturation in negative ion sources

    SciTech Connect

    Mochalskyy, S.; Lifschitz, A. F.; Minea, T.

    2012-06-01

    The extraction of negatively charged particles from a negative ion source is one of the crucial issues in the development of the neutral beam injector system for future experimental reactor ITER. Full 3D electrostatic particle-in-cell Monte Carlo collision code - ONIX [S. Mochalskyy et al., Nucl. Fusion 50, 105011 (2010)] - is used to simulate the hydrogen plasma behaviour and the extracted particle features in the vicinity of the plasma grid, both sides of the aperture. It is found that the contribution to the extracted negative ion current of ions born in the volume is small compared with that of ions created at the plasma grid walls. The parametric study with respect to the rate of negative ions released from the walls shows an optimum rate. Beyond this optimum, a double layer builds-up by the negative ion charge density close to the grid aperture surface reducing thus extraction probability, and therefore the extracted current. The effect of the extraction potential and magnetic field magnitudes on the extraction is also discussed. Results are in good agreement with available experimental data.

  5. [Chemotherapies of negative schizophrenia].

    PubMed

    Petit, M; Dollfus, S

    1991-01-01

    Five years ago, Goldberg claimed that negative symptoms of schizophrenia do respond to neuroleptics. This apparent discovery is, in fact, a very common way of thinking for European schools of psychiatry, specially the French one guided by Delay and Deniker. Initially focused on reserpine and some alerting phenothiazines such as thioproperazine, this opinion has been extended to benzamides in the 1970s. The analysis of the publications devoted to this point indicates that several drugs are actually considered as potent disinhibitors (i.e. active on negative symptoms of schizophrenia): Phenothiazines: As shown in the controlled studies by Itil (1971), Poirier-Littré (1988), fluphenazine and pipotiazine improve the BPRS anergia factor and the SANS score. Butyrophenones: The first description of the "imipramine like" effect of trifluperidol by Janssen (1959) initiated the studies by Gallant (1960), Fox (1963). They compared trifluperidol at low doses versus haloperidol and chlorpromazine at medium and high doses, BPRS anergia factor improved only at low doses. Diphenylbutylpiperidines (DPBP): Meltzer's review (1986) concluded to the efficacy of such drugs on negative symptoms appearing as a specific biochemical relationship effect. A definite analysis about doses leads to a very different interpretation: DPBP low doses and only low doses improved negative symptoms as much as some low doses of phenothiazines. On the opposite, DPBP, phenothiazines and butyrophenones high doses are inefficient.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1683624

  6. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  7. Cryo-negative staining.

    PubMed

    Adrian, M; Dubochet, J; Fuller, S D; Harris, J R

    1998-01-01

    A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of ammonium molybdate, which we term cryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thinner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associated sample flattening, together with reduced stain granularity, generates high contrast cryo-images of superior quality to conventional air-dry negative staining. Image features characteristic of unstained vitrified cryo-electron microscopic specimens are present, but with reverse contrast. Examples of cryo-negative staining of several particulate biological samples are shown, including bacteriophage T2, tobacco mosaic virus (TMV), bovine liver catalase crystals, tomato bushy stunt virus (TBSV), turnip yellow mosaic virus (TYMV), keyhole limpet hemocyanin (KLH) types 1 and 2, the 20S proteasome from moss and the E. coli chaperone GroEL. Densitometric quantitation of the mass-density of cryo-negatively stained bacteriophage T2 specimens before and after freeze-drying within the TEM indicates a water content of 30% in the vitreous specimen. Determination of the image resolution from cryo-negatively stained TMV rods and catalase crystals shows the presence of optical diffraction data to ca. 10 A and 11.5 A, respectively. For cryo-negatively stained vitrified catalase crystals, electron diffraction shows that atomic resolution is preserved (to better than 20 diffraction orders and less than 3 A). The electron diffraction resolution is reduced to ca. 10 A when catalase crystal specimens are

  8. Negative Mass Propulsion

    NASA Astrophysics Data System (ADS)

    Winterberg, F.

    Schrödinger's analysis of the Dirac equation gives a hint for the existence of negative masses hidden behind positive masses. But their use for propulsion by reducing the inertia of matter for example, in the limit of macroscopic bodied with zero rest mass, depends on a technical solution to free them from their imprisonment by positive masses. It appears that there are basically two ways this might be achieved: 1. By the application of strong electromagnetic or gravitational fields or by high particle energies. 2. By searching for places in the universe where nature has already done this separation, and from where the negative masses can be mined. The first of these two possibilities is for all practical means excluded, because if possible at all, it would depend on electromagnetic or gravitational fields with strength beyond what is technically attainable, or on extremely large likewise not attainable particle energies. With regard to the 2nd possibility, it has been observed that non-baryonic cold dark matter tends to accumulate near the center of galaxies, or places in the universe which have a large gravitational potential well. Because of the equivalence principle of general relativity, the attraction towards the center of a gravitational potential well, produced by a positive mass, is for negative masses the same as for positive masses, and large amounts of negative masses might have over billions of years been trapped in these gravitational potential wells. Now it just happens that the center of the moon is a potential well, not too deep that it cannot be reached by making a tunnel through the moon, not possible for the deeper potential well of the earth, where the temperature and pressure are too high. Making a tunnel through the moon, provided there is a good supply of negative mass, could revolutionize interstellar space flight. A sequence of thermonuclear shape charges would make such tunnel technically feasible.

  9. Hydrogen production by Cyanobacteria

    PubMed Central

    Dutta, Debajyoti; De, Debojyoti; Chaudhuri, Surabhi; Bhattacharya, Sanjoy K

    2005-01-01

    The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical), Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source. PMID:16371161

  10. Hydrogen transport membranes

    DOEpatents

    Mundschau, Michael V.

    2005-05-31

    Composite hydrogen transport membranes, which are used for extraction of hydrogen from gas mixtures are provided. Methods are described for supporting metals and metal alloys which have high hydrogen permeability, but which are either too thin to be self supporting, too weak to resist differential pressures across the membrane, or which become embrittled by hydrogen. Support materials are chosen to be lattice matched to the metals and metal alloys. Preferred metals with high permeability for hydrogen include vanadium, niobium, tantalum, zirconium, palladium, and alloys thereof. Hydrogen-permeable membranes include those in which the pores of a porous support matrix are blocked by hydrogen-permeable metals and metal alloys, those in which the pores of a porous metal matrix are blocked with materials which make the membrane impervious to gases other than hydrogen, and cermets fabricated by sintering powders of metals with powders of lattice-matched ceramic.

  11. Hydrogen Technologies Safety Guide

    SciTech Connect

    Rivkin, C.; Burgess, R.; Buttner, W.

    2015-01-01

    The purpose of this guide is to provide basic background information on hydrogen technologies. It is intended to provide project developers, code officials, and other interested parties the background information to be able to put hydrogen safety in context. For example, code officials reviewing permit applications for hydrogen projects will get an understanding of the industrial history of hydrogen, basic safety concerns, and safety requirements.

  12. Solar hydrogen generator

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Sabol, A. P. (Inventor)

    1977-01-01

    An apparatus, using solar energy to manufacture hydrogen by dissociating water molecules into hydrogen and oxygen molecules is described. Solar energy is concentrated on a globe containing water thereby heating the water to its dissociation temperature. The globe is pervious to hydrogen molecules permitting them to pass through the globe while being essentially impervious to oxygen molecules. The hydrogen molecules are collected after passing through the globe and the oxygen molecules are removed from the globe.

  13. Disposable Hydrogen Generator.

    PubMed

    Brewer, J H; Allgeier, D L

    1965-02-26

    A convenient means of producing hydrogen gas for anaerobe jars or other situations where 2 liters of hydrogen will suffice is described. Hydrogen gas is produced by the chemical action of magnesium metal, zinc chloride, sodium chloride, and water within a unique plastic and aluminum foil envelope. That there is no excessive buildup of hydrogen greatly reduces the hazard of explosion. The gas-producing units are simple to activate and may be discarded after use.

  14. Correlation of H/sup -/ production and the work function of a surface in a hydrogen plasma

    SciTech Connect

    Wada, M.

    1983-03-01

    Surface-plasma negative hydrogen ion sources are being developed as possible parts for future neutral beam systems. In these ion sources, negative hydrogen ions (H/sup -/) are produced at low work function metal surfaces immersed in hydrogen plasmas. To investigate the correlation between the work function and the H/sup -/ production at the surface with a condition similar to the one in the actual plasma ion source, these two parameters were simultaneously measured in the hydrogen plasma environment.

  15. Liquid metal hydrogen barriers

    DOEpatents

    Grover, George M.; Frank, Thurman G.; Keddy, Edward S.

    1976-01-01

    Hydrogen barriers which comprise liquid metals in which the solubility of hydrogen is low and which have good thermal conductivities at operating temperatures of interest. Such barriers are useful in nuclear fuel elements containing a metal hydride moderator which has a substantial hydrogen dissociation pressure at reactor operating temperatures.

  16. Purification of Hydrogen

    DOEpatents

    Newton, A S

    1950-12-05

    Disclosed is a process for purifying hydrogen containing various gaseous impurities by passing the hydrogen over a large surface of uranium metal at a temperature above the decomposition temperature of uranium hydride, and below the decomposition temperature of the compounds formed by the combination of the uranium with the impurities in the hydrogen.

  17. Flash hydrogenation of coal

    DOEpatents

    Manowitz, Bernard; Steinberg, Meyer; Sheehan, Thomas V.; Winsche, Warren E.; Raseman, Chad J.

    1976-01-01

    A process for the hydrogenation of coal comprising the contacting of powdered coal with hydrogen in a rotating fluidized bed reactor. A rotating fluidized bed reactor suitable for use in this process is also disclosed. The coal residence time in the reactor is limited to less than 5 seconds while the hydrogen contact time is not in excess of 0.2 seconds.

  18. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, G.R.

    1999-08-03

    A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.

  19. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, Ganapati Rao

    1999-01-01

    A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

  20. Biological hydrogen photoproduction

    SciTech Connect

    Nemoto, Y.

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  1. Think (Gram) negative!

    PubMed Central

    2010-01-01

    The increasing prevalence of multiresistant Gram-negative bacteria of the Enterobacteriaceae family in Europe is a worrisome phenomenon. Extended spectrum betalactamase-producing Escherichia coli strains are widespread in the community and are frequently imported into the hospital. Of even more concern is the spread of carbapenem-resistant strains of Klebsiella spp. from regions where they are already endemic. Antibiotic use is a main driver of antibiotic resistance, which again increases broad spectrum antibiotic use, resulting in a vicious circle that is difficult to interrupt. The present commentary highlights important findings of a surveillance study of antimicrobial use and resistance in German ICUs over 8 years with a focus on Gram-negative resistance. PMID:20587087

  2. Negative refraction and superconductivity

    NASA Astrophysics Data System (ADS)

    Amariti, Antonio; Forcella, Davide; Mariotti, Alberto; Siani, Massimo

    2011-10-01

    We discuss exotic properties of charged hydrodynamical systems, in the broken superconducting phase, probed by electromagnetic waves. Motivated by general arguments from hydrodynamics, we observe that negative refraction, namely the propagation in opposite directions of the phase velocities and of the energy flux, is expected for low enough frequencies. We corroborate this general idea by analyzing a holographic superconductor in the AdS/CFT correspondence, where the response functions can be explicitly computed. We study the dual gravitational theory both in the probe and in the backreacted case. We find that, while in the first case the refractive index is positive at every frequency, in the second case there is negative refraction at low enough frequencies. This is in agreement with hydrodynamic considerations.

  3. The negative repetition effect.

    PubMed

    Mulligan, Neil W; Peterson, Daniel J

    2013-09-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising negative repetition effect, in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and across pairs, the target words were drawn from a small set of categories. In the repetition condition, the pairs were initially presented in a random order and then presented a 2nd time blocked by the category of the target words. In the single presentation condition, the pairs were presented only in the blocked order. Participants in the former condition recalled fewer target words on a free recall test despite having seen the word pairs twice (the negative repetition effect). This phenomenon is explored in a series of 5 experiments assessing 3 theoretical accounts of the effect. The experiments demonstrate that the negative repetition effect generalizes over multiple encoding conditions (reading and generative encoding), over different memory tests (free and cued recall), and over delay (5 min and 2 days). The results argue against a retrieval account and a levels-of-processing account but are consistent with the item-specific-relational account, the account upon which the effect was initially predicated. PMID:23421508

  4. Hydrogen separation process

    DOEpatents

    Mundschau, Michael; Xie, Xiaobing; Evenson, IV, Carl; Grimmer, Paul; Wright, Harold

    2011-05-24

    A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

  5. Safe venting of hydrogen

    SciTech Connect

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  6. Microstructures of negative and positive azeotropes.

    PubMed

    Shephard, J J; Callear, S K; Imberti, S; Evans, J S O; Salzmann, C G

    2016-07-28

    Azeotropes famously impose fundamental restrictions on distillation processes, yet their special thermodynamic properties make them highly desirable for a diverse range of industrial and technological applications. Using neutron diffraction, we investigate the structures of two prototypical azeotropes, the negative acetone-chloroform and the positive benzene-methanol azeotrope. C-HO hydrogen bonding is the dominating interaction in the negative azeotrope but C-ClO halogen bonding contributes as well. Hydrogen-bonded chains of methanol molecules, which are on average longer than in pure methanol, are the defining structural feature of the positive azeotrope illustrating the fundamentally different local mixing in the two kinds of azeotropes. The emerging trend for both azeotropes is that the more volatile components experience the more pronounced structural changes in their local environments as the azeotropes form. The mixing of the acetone-chloroform azeotrope is essentially random above 20 Å, where the running Kirkwood-Buff integrals of our structural model converge closely to the ones expected from thermodynamic data. The benzene-methanol azeotrope on the other hand displays extended methanol-rich regions and consequently the running Kirkwood-Buff integrals oscillate up to at least 60 Å. Our study provides the first experimental insights into the microstructures of azeotropes and a direct link with their thermodynamic properties. Ultimately, this will provide a route for creating tailored molecular environments in azeotropes to improve and fine-tune their performances. PMID:27367534

  7. Photobiological hydrogen production.

    PubMed

    Asada, Y; Miyake, J

    1999-01-01

    The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase via cyanobacterial ferredoxin was demonstrated in the presence of light. Genetic transformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum was successful; the active enzyme was expressed in PCC7942. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Coculture of Rhodobacter and Clostriudium was applied for hydrogen production from glucose. A mutant strain of Rhodobacter sphaeroides RV whose light-harvesting proteins were altered was obtained by UV irradiation. Hydrogen productivity by the mutant was improved when irradiated with monochromatic light of some wavelengths. The development of photobioreactors for hydrogen production is also reviewed.

  8. Hydrogen storage methods.

    PubMed

    Züttel, Andreas

    2004-04-01

    Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m(-3), approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen

  9. Hydrogen storage methods

    NASA Astrophysics Data System (ADS)

    Züttel, Andreas

    Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m-3, approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen is

  10. Negative Casimir entropies

    NASA Astrophysics Data System (ADS)

    Li, Yang; Milton, Kimball

    In the last decade, various results on the entropy related to the Casimir interactions between two bodies have been obtained and the striking feature that negative values of Casimir entropy frequently appear. The origin of this effect lies in many factors, such as the dissipation of the materials, the geometry of the configuration and so on. We recently investigated the entropies of one body systems. Although the self-free energy of one body systems are always divergent, the self-entropy could be finite in many cases. These phenomenon may throw more light on thermal dynamical behavior of quantum field systems.

  11. Hydrogen Filling Station

    SciTech Connect

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  12. Classroom Management and Negative Reinforcement.

    ERIC Educational Resources Information Center

    Tauber, Robert T.

    Of the four simple consequences for behavior, none is more misunderstood than negative reinforcement. A Negative Reinforcement Quiz administered to 233 student teachers from two universities revealed that the vast majority of respondents mistakenly viewed negative reinforcement as a synonym for punishment, and believe that negative reinforcement…

  13. Polarized negative ions

    SciTech Connect

    Haeberli, W.

    1981-04-01

    This paper presents a survey of methods, commonly in use or under development, to produce beams of polarized negative ions for injection into accelerators. A short summary recalls how the hyperfine interaction is used to obtain nuclear polarization in beams of atoms. Atomic-beam sources for light ions are discussed. If the best presently known techniques are incorporated in all stages of the source, polarized H/sup -/ and D/sup -/ beams in excess of 10 ..mu..A can probably be achieved. Production of polarized ions from fast (keV) beams of polarized atoms is treated separately for atoms in the H(25) excited state (Lamb-Shift source) and atoms in the H(1S) ground state. The negative ion beam from Lamb-Shift sources has reached a plateau just above 1 ..mu..A, but this beam current is adequate for many applications and the somewhat lower beam current is compensated by other desirable characteristics. Sources using fast polarized ground state atoms are in a stage of intense development. The next sections summarize production of polarized heavy ions by the atomic beam method, which is well established, and by optical pumping, which has recently been demonstrated to yield very large nuclear polarization. A short discussion of proposed ion sources for polarized /sup 3/He/sup -/ ions is followed by some concluding remarks.

  14. Negative magnetoresistivity in holography

    NASA Astrophysics Data System (ADS)

    Sun, Ya-Wen; Yang, Qing

    2016-09-01

    Negative magnetoresistivity is a special magnetotransport property associated with chiral anomaly in four dimensional chiral anomalous systems, which refers to the transport behavior that the DC longitudinal magnetoresistivity decreases with increasing magnetic field. We calculate the longitudinal magnetoconductivity in the presence of back-reactions of the magnetic field to gravity in holographic zero charge and axial charge density systems with and without axial charge dissipation. In the absence of axial charge dissipation, we find that the quantum critical conductivity grows with increasing magnetic field when the backreaction strength is larger than a critical value, in contrast to the monotonically decreasing behavior of quantum critical conductivity in the probe limit. With axial charge dissipation, we find the negative magnetoresistivity behavior. The DC longitudinal magnetoconductivity scales as B in the large magnetic field limit, which deviates from the exact B 2 scaling of the probe limit result. In both cases, the small frequency longitudinal magnetoconductivity still agrees with the formula obtained from the hydrodynamic linear response theory, even in the large magnetic field limit.

  15. Ultrafine hydrogen storage powders

    DOEpatents

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  16. Hydrogen interactions with metals

    NASA Technical Reports Server (NTRS)

    Mclellan, R. B.; Harkins, C. G.

    1975-01-01

    Review of the literature on the nature and extent of hydrogen interactions with metals and the role of hydrogen in metal failure. The classification of hydrogen-containing systems is discussed, including such categories as covalent hydrides, volatile hydrides, polymeric hydrides, and transition metal hydride complexes. The use of electronegativity as a correlating parameter in determining hydride type is evaluated. A detailed study is made of the thermodynamics of metal-hydrogen systems, touching upon such aspects as hydrogen solubility, the positions occupied by hydrogen atoms within the solvent metal lattice, the derivation of thermodynamic functions of solid solutions from solubility data, and the construction of statistical models for hydrogen-metal solutions. A number of theories of hydrogen-metal bonding are reviewed, including the rigid-band model, the screened-proton model, and an approach employing the augmented plane wave method to solve the one-electron energy band problem. Finally, the mechanism of hydrogen embrittlement is investigated on the basis of literature data concerning stress effects and the kinetics of hydrogen transport to critical sites.

  17. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Steinbugler, M.; Kreutz, T.

    1998-08-01

    In this progress report (covering the period May 1997--May 1998), the authors summarize results from ongoing technical and economic assessments of hydrogen energy systems. Generally, the goal of their research is to illuminate possible pathways leading from present hydrogen markets and technologies toward wide scale use of hydrogen as an energy carrier, highlighting important technologies for RD and D. Over the past year they worked on three projects. From May 1997--November 1997, the authors completed an assessment of hydrogen as a fuel for fuel cell vehicles, as compared to methanol and gasoline. Two other studies were begun in November 1997 and are scheduled for completion in September 1998. The authors are carrying out an assessment of potential supplies and demands for hydrogen energy in the New York City/New Jersey area. The goal of this study is to provide useful data and suggest possible implementation strategies for the New York City/ New Jersey area, as the Hydrogen Program plans demonstrations of hydrogen vehicles and refueling infrastructure. The authors are assessing the implications of CO{sub 2} sequestration for hydrogen energy systems. The goals of this work are (a) to understand the implications of CO{sub 2} sequestration for hydrogen energy system design; (b) to understand the conditions under which CO{sub 2} sequestration might become economically viable; and (c) to understand design issues for future low-CO{sub 2} emitting hydrogen energy systems based on fossil fuels.

  18. Application of anomalous diffusion in production of negative ions

    SciTech Connect

    Jimbo, K.

    1984-11-01

    The production of negative hydrogen ions is investigated in the reflex-type negative ion sources. When anomalous diffusion in the positive column was found by Hoh and Lehnert (Phys. Fluids 3, 600 (1960)), it was pointed out that the large particle loss produced by anomalous diffusion is compensated for by the larger particle production inside the plasma. In the present experiments anomalous diffusion was artificially encouraged by changing the radial electric field inside the reflex discharge. Apparent encouragement of negative ion current by the increase of the density fluctuation amplitude is observed. Twice as much negative ion current was obtained with the artificial encouragement as without. On the other hand, the larger extracted negative ion current was observed with a lower electron temperature, which is calculated from the anomalous diffusion coefficient derived from a simple nonlinear theory. This result is consistent with Wadehra's calculated results (Appl. Phys. Lett. 35, 917 (1979)).

  19. Hydrogen ionic plasma generated using Al plasma grid

    NASA Astrophysics Data System (ADS)

    Oohara, W.; Anegawa, N.; Egawa, M.; Kawata, K.; Kamikawa, T.

    2016-08-01

    Negative hydrogen ions are produced in the apertures of a plasma grid made of aluminum under the irradiation of positive ions, generating an ionic plasma consisting of positive and negative ions. The saturation current ratio obtained using a Langmuir probe reflects the existence ratio of electrons and is found to increase in connection with the diffusion of the ionic plasma. The local increment of the current ratio suggests the collapse of negative ions and the replacement of detached electrons.

  20. Analysis of hydrogen isotope mixtures

    DOEpatents

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

  1. Negative ion source

    DOEpatents

    Leung, K.N.; Ehlers, K.W.

    1982-08-06

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  2. Negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.

    1984-01-01

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  3. Negative ion source

    DOEpatents

    Leung, K.N.; Ehlers, K.W.

    1984-12-04

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field. 14 figs.

  4. Do `negative' temperatures exist?

    NASA Astrophysics Data System (ADS)

    Lavenda, B. H.

    1999-06-01

    A modification of the second law is required for a system with a bounded density of states and not the introduction of a `negative' temperature scale. The ascending and descending branches of the entropy versus energy curve describe particle and hole states, having thermal equations of state that are given by the Fermi and logistic distributions, respectively. Conservation of energy requires isentropic states to be isothermal. The effect of adiabatically reversing the field is entirely mechanical because the only difference between the two states is their energies. The laws of large and small numbers, leading to the normal and Poisson approximations, characterize statistically the states of infinite and zero temperatures, respectively. Since the heat capacity also vanishes in the state of maximum disorder, the third law can be generalized in systems with a bounded density of states: the entropy tends to a constant as the temperature tends to either zero or infinity.

  5. Negative Optical Torque

    PubMed Central

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C. T.

    2014-01-01

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of “negative optical torque”, meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained. PMID:25226863

  6. Negative Entropy of Life

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2015-10-01

    We modify Newtonian gravity to probabilistic quantum mechanical gravity to derive strong coupling. If this approach is valid, we should be able to extend it to the physical body (life) as follows. Using Boltzmann equation, we get the entropy of the universe (137) as if its reciprocal, the fine structure constant (ALPHA), is the hidden candidate representing the negative entropy of the universe which is indicative of the binary information as its basis (http://www.arXiv.org/pdf/physics0210040v5). Since ALPHA relates to cosmology, it must relate to molecular biology too, with the binary system as the fundamental source of information for the nucleotides of the DNA as implicit in the book by the author: ``Quantum Consciousness - The Road to Reality.'' We debate claims of anthropic principle based on the negligible variation of ALPHA and throw light on thermodynamics. We question constancy of G in multiple ways.

  7. Hydrogen powered bus

    ScienceCinema

    None

    2016-07-12

    Take a ride on a new type of bus, fueled by hydrogen. These hydrogen taxis are part of a Department of Energy-funded deployment of hydrogen powered vehicles and fueling infrastructure at nine federal facilities across the country to demonstrate this market-ready advanced technology. Produced and leased by Ford Motor Company , they consist of one 12- passenger bus and one nine-passenger bus. More information at: http://go.usa.gov/Tgr

  8. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  9. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Steinbugler, M.; Dennis, E.

    1995-09-01

    For several years, researchers at Princeton University`s Center for Energy and Environmental Studies have carried out technical and economic assessments of hydrogen energy systems. Initially, we focussed on the long term potential of renewable hydrogen. More recently we have explored how a transition to renewable hydrogen might begin. The goal of our current work is to identify promising strategies leading from near term hydrogen markets and technologies toward eventual large scale use of renewable hydrogen as an energy carrier. Our approach has been to assess the entire hydrogen energy system from production through end-use considering technical performance, economics, infrastructure and environmental issues. This work is part of the systems analysis activity of the DOE Hydrogen Program. In this paper we first summarize the results of three tasks which were completed during the past year under NREL Contract No. XR-11265-2: in Task 1, we carried out assessments of near term options for supplying hydrogen transportation fuel from natural gas; in Task 2, we assessed the feasibility of using the existing natural gas system with hydrogen and hydrogen blends; and in Task 3, we carried out a study of PEM fuel cells for residential cogeneration applications, a market which might have less stringent cost requirements than transportation. We then give preliminary results for two other tasks which are ongoing under DOE Contract No. DE-FG04-94AL85803: In Task 1 we are assessing the technical options for low cost small scale production of hydrogen from natural gas, considering (a) steam reforming, (b) partial oxidation and (c) autothermal reforming, and in Task 2 we are assessing potential markets for hydrogen in Southern California.

  10. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  11. National hydrogen energy roadmap

    SciTech Connect

    None, None

    2002-11-01

    This report was unveiled by Energy Secretary Spencer Abraham in November 2002 and provides a blueprint for the coordinated, long-term, public and private efforts required for hydrogen energy development. Based on the results of the government-industry National Hydrogen Energy Roadmap Workshop, held in Washington, DC on April 2-3, 2002, it displays the development of a roadmap for America's clean energy future and outlines the key barriers and needs to achieve the hydrogen vision goals defined in

  12. Hydrogen energy creeps forward

    NASA Astrophysics Data System (ADS)

    Graff, G.

    1983-05-01

    There have been hopeful forecasts of a 21st centry 'hydrogen economy' in which cheap hydrogen fuel would finally end mankind's dependence on petroleum fuels. The present investigation is concerned with developments related to the possible realization of such forecasts. One vital factor involves the feasibility to provide hydrogen at competitive prices for use as a fuel. Industrial hydrogen is too expensive for applications involving a competition with currently used common fuels. A number of investigations are being conducted in the U.S. and in other countries with the aim to develop an economical process by which hydrogen can be obtained from water. There exist already a great number of feasible different approaches for obtaining hydrogen on the basis of the decomposition of the water molecule. However, problems still to be solved are related to the development of any of these approaches to the point of economic viability. Another crucial factor concerns the strorage of hydrogen. Automakers are testing hydrogen-powered cars in which hydrogen is stored in liquid form or with the aid of metal hydrides.

  13. HYDROGEN SEPARATION MEMBRANES

    SciTech Connect

    Donald P. McCollor; John P. Kay

    1999-08-01

    A likely membrane for future testing of high-temperature hydrogen separation from a gasification product stream was targeted as an inorganic analog of a dense-metal membrane, where the hydrogen would dissolve into and diffuse through the membrane structure. An amorphous membrane such as zinc sulfide appeared to be promising. Previously, ZnS film coating tests had been performed using an electron-beam vacuum coating instrument, with zinc films successfully applied to glass substrates. The coatings appeared relatively stable in air and in a simple simulated gasification atmosphere at elevated temperature. Because the electron-beam coating instrument suffered irreparable breakdown, several alternative methods were tested in an effort to produce a nitrogen-impermeable, hydrogen-permeable membrane on porous sintered steel substrates. None of the preparation methods proved successful in sealing the porous substrate against nitrogen gas. To provide a nitrogen-impermeable ZnS material to test for hydrogen permeability, two ZnS infrared sample windows were purchased. These relatively thick ''membranes'' did not show measurable permeation of hydrogen, either due to lack of absorption or a negligible permeation rate due to their thickness. To determine if hydrogen was indeed adsorbed, thermogravimetric and differential thermal analyses tests were performed on samples of ZnS powder. A significant uptake of hydrogen gas occurred, corresponding to a maximum of 1 mole H{sub 2} per 1 mole ZnS at a temperature of 175 C. The hydrogen remained in the material at ambient temperature in a hydrogen atmosphere, but approximately 50% would be removed in argon. Reheating in a hydrogen atmosphere resulted in no additional hydrogen uptake. Differential scanning calorimetry indicated that the hydrogen uptake was probably due to the formation of a zinc-sulfur-hydrogen species resulting in the formation of hydrogen sulfide. The zinc sulfide was found to be unstable above approximately 200 C

  14. Hydrogen ion microlithography

    DOEpatents

    Tsuo, Y. Simon; Deb, Satyen K.

    1990-01-01

    Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing.

  15. Hydrogen ion microlithography

    DOEpatents

    Tsuo, Y.S.; Deb, S.K.

    1990-10-02

    Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing. 6 figs.

  16. Thin film hydrogen sensor

    DOEpatents

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  17. Sustainable hydrogen production

    SciTech Connect

    Block, D.L.; Linkous, C.; Muradov, N.

    1996-01-01

    This report describes the Sustainable Hydrogen Production research conducted at the Florida Solar Energy Center (FSEC) for the past year. The report presents the work done on the following four tasks: Task 1--production of hydrogen by photovoltaic-powered electrolysis; Task 2--solar photocatalytic hydrogen production from water using a dual-bed photosystem; Task 3--development of solid electrolytes for water electrolysis at intermediate temperatures; and Task 4--production of hydrogen by thermocatalytic cracking of natural gas. For each task, this report presents a summary, introduction/description of project, and results.

  18. Enzymatic Hydrogen Production from Starch and Water

    SciTech Connect

    Zhang, Y.-H. Percival; Evans, Barbara R; Mielenz, Jonathan R; Hopkins, Robert C.; Adams, Michael W. W.

    2007-01-01

    A novel enzymatic reaction was conducted for producing hydrogen from starch and water at 30oC. The overall reaction comprised of 13 enzymes, 1 cofactor (NADP+), and phosphate was driven by energy stored in carbohydrate starch according to the overall stoichiometry stoichiometric reaction of C6H10O5 (l) + 7 H2O (l) --> 12 H2 (g) + 6 CO2 (g). It is spontaneous and unidirectional because of negative Gibbs free energy and the removal of gaseous products from the aqueous reaction solution. With technology improvement and integration with fuel cells, this technology would be suitable for mobile applications and also solve the challenges associated with hydrogen storage, distribution, and infrastructure in a hydrogen economy.

  19. Hydrogen peroxide treatment of TCE contaminated soil

    SciTech Connect

    Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

    1993-12-31

    Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil.

  20. 19. Print from copy negative (original glass plate negative in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Print from copy negative (original glass plate negative in Tippecanoe County Historical Society.) Original photo dated May 7, 1893. View north, south side. - Big Four Depot, 10 South Second Street, Lafayette, Tippecanoe County, IN

  1. Negative Expertise: Comparing Differently Tenured Elder Care Nurses' Negative Knowledge

    ERIC Educational Resources Information Center

    Gartmeier, Martin; Lehtinen, Erno; Gruber, Hans; Heid, Helmut

    2011-01-01

    Negative expertise is conceptualised as the professional's ability to avoid errors during practice due to certain cognitive agencies. In this study, negative knowledge (i.e. knowledge about what is wrong in a certain context and situation) is conceptualised as one such agency. This study compares and investigates the negative knowledge of elder…

  2. Enhancing hydrogen spillover and storage

    DOEpatents

    Yang, Ralph T.; Li, Yingwel; Lachawiec, Jr., Anthony J.

    2011-05-31

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonification as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  3. Combination moisture and hydrogen getter

    DOEpatents

    Not Available

    1982-04-29

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the reusltant hydrogen.

  4. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, Larry A.; Mead, Keith E.; Smith, Henry M.

    1983-01-01

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  5. Enhancing hydrogen spillover and storage

    DOEpatents

    Yang, Ralph T; Li, Yingwei; Lachawiec, Jr., Anthony J

    2013-02-12

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonication as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  6. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, L.A.; Mead, K.E.; Smith, H.M.

    1983-09-20

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (1) a solid acetylenic compound and (2) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  7. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    DOEpatents

    Hindin, Saul G.; Roberts, George W.

    1980-08-12

    A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst.

  8. Hydrogenated graphene and hydrogenated silicene: computational insights.

    PubMed

    Nguyen, Manh-Thuong; Phong, Pham Nam; Tuyen, Nguyen Duc

    2015-06-01

    Density functional calculations are performed to study the energetic, structural, and electronic properties of graphene and silicene functionalized with hydrogen. Our calculations predict that H atoms bind much more strongly to silicene than to graphene. The adsorbed H atoms tend to cooperatively stabilize each other leading to a two-dimensional nucleation and growth mechanism. The different structural and electronic modifications induced by H in fully functionalized graphene and silicene (known as graphane and silicane) are also explained. Finally, the electronic properties of defective graphane with multiple hydrogen vacancies are investigated. Engineering the vacancies in graphane offers a way to modify the electronic properties of this material.

  9. Coagulase-Negative Staphylococci

    PubMed Central

    Heilmann, Christine; Peters, Georg

    2014-01-01

    SUMMARY The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides. PMID:25278577

  10. Negative ion source

    DOEpatents

    Delmore, James E.

    1987-01-01

    A method and apparatus for providing a negative ion source accelerates electrons away from a hot filament electron emitter into a region of crossed electric and magnetic fields arranged in a magnetron configuration. During a portion of the resulting cycloidal path, the electron velocity is reduced below its initial value. The electron accelerates as it leaves the surface at a rate of only slightly less than if there were no magnetic field, thereby preventing a charge buildup at the surface of the emitter. As the electron traverses the cycloid, it is decelerated during the second, third, and fourth quadrants, then reeccelerated as it approaches the end of the fourth quadrant to regain its original velocity. The minimum velocity occurs during the fourth quadrant, and corresponds to an electron temperature of 200.degree. to 500.degree. for the electric and magnetic fields commonly encountered in the ion sources of magnetic sector mass spectrometers. An ion source using the above-described thermalized electrons is also disclosed.

  11. Plasmonics without negative dielectrics

    NASA Astrophysics Data System (ADS)

    Della Giovampaola, Cristian; Engheta, Nader

    2016-05-01

    Plasmonic phenomena are exhibited in light-matter interaction involving materials whose real parts of permittivity functions attain negative values at operating wavelengths. However, such materials usually suffer from dissipative losses, thus limiting the performance of plasmon-based optical devices. Here, we utilize an alternative methodology that mimics a variety of plasmonic phenomena by exploiting the well-known structural dispersion of electromagnetic modes in bounded guided-wave structures filled with only materials with positive permittivity. A key issue in the design of such structures is prevention of mode coupling, which can be achieved by implementing thin metallic wires at proper interfaces. This method, which is more suitable for lower frequencies, allows designers to employ conventional dielectrics and highly conductive metals for which the loss is low at these frequencies, while achieving plasmonic features. We demonstrate, numerically and analytically, that this platform can provide surface plasmon polaritons, local plasmonic resonance, plasmonic cloaking, and epsilon-near-zero-based tunneling using conventional positive-dielectric materials.

  12. Coagulase-negative staphylococci.

    PubMed

    Becker, Karsten; Heilmann, Christine; Peters, Georg

    2014-10-01

    The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides. PMID:25278577

  13. Hydrogen /Hydride/-air secondary battery

    NASA Technical Reports Server (NTRS)

    Sarradin, J.; Bronoel, G.; Percheron-Guegan, A.; Achard, J. C.

    1979-01-01

    The use of metal hydrides as negative electrodes in a hydrogen-air secondary battery seems promising. However, in an unpressurized cell, more stable hydrides that LaNi5H6 must be selected. Partial substitutions of nickel by aluminium or manganese increase the stability of hydrides. Combined with an air reversible electrode, a specific energy close to 100 Wh/kg can be expected.

  14. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    DOEpatents

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  15. Hydrogen in amorphous silicon

    SciTech Connect

    Peercy, P. S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH/sub 1/) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon.

  16. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  17. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, B.S.; Lauf, R.J.

    1995-09-19

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors. 8 figs.

  18. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  19. Towards a Hydrogen Economy

    SciTech Connect

    Sherif, S.A.; Barbir, Frano; Veziroglu, T.N.

    2005-07-01

    From electrolysis and thermolysis to production from biomass, hydrogen production methods are falling into place. So is storage, via all modes of gaseous, liquid, slush, and metal hydride systems. But proponents need to address the perception that hydrogen poses a severe safety risk, since the evidence suggests its risks are of the same order of magnitude as gasoline or natural gas.

  20. Hydrogen Fuel Quality

    SciTech Connect

    Rockward, Tommy

    2012-07-16

    For the past 6 years, open discussions and/or meetings have been held and are still on-going with OEM, Hydrogen Suppliers, other test facilities from the North America Team and International collaborators regarding experimental results, fuel clean-up cost, modeling, and analytical techniques to help determine levels of constituents for the development of an international standard for hydrogen fuel quality (ISO TC197 WG-12). Significant progress has been made. The process for the fuel standard is entering final stages as a result of the technical accomplishments. The objectives are to: (1) Determine the allowable levels of hydrogen fuel contaminants in support of the development of science-based international standards for hydrogen fuel quality (ISO TC197 WG-12); and (2) Validate the ASTM test method for determining low levels of non-hydrogen constituents.

  1. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  2. Atomic hydrogen rocket engine

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Flurchick, K.

    1981-01-01

    A rocket using atomic hydrogen propellant is discussed. An essential feature of the proposed engine is that the atomic hydrogen fuel is used as it is produced, thus eliminating the necessity of storage. The atomic hydrogen flows into a combustion chamber and recombines, producing high velocity molecular hydrogen which flows out an exhaust port. Standard thermodynamics, kinetic theory and wall recombination cross-sections are used to predict a thrust of approximately 1.4 N for a RF hydrogen flow rate of 4 x 10 to the 22nd/sec. Specific impulses are nominally from 1000 to 2000 sec. It is predicted that thrusts on the order of one Newton and specific impulses of up to 2200 sec are attainable with nominal RF discharge fluxes on the order of 10 to the 22nd atoms/sec; further refinements will probably not alter these predictions by more than a factor of two.

  3. Negativity bias and basic values.

    PubMed

    Schwartz, Shalom H

    2014-06-01

    Basic values explain more variance in political attitudes and preferences than other personality and sociodemographic variables. The values most relevant to the political domain are those likely to reflect the degree of negativity bias. Value conflicts that represent negativity bias clarify differences between what worries conservatives and liberals and suggest that relations between ideology and negativity bias are linear. PMID:24970450

  4. Conservatives, liberals, and "the negative".

    PubMed

    Charney, Evan

    2014-06-01

    The authors connect conservatism with aversion to negativity via the tendentious use of the language of threats to characterize conservatism, but not liberalism. Their reliance upon an objective conception of the negative ignores the fact that much of the disagreement between liberals and conservatives is over whether or not one and the same state of affairs is negative or positive. PMID:24970432

  5. Hydrogen Tunneling in Enzymes and Biomimetic Models

    SciTech Connect

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2013-12-20

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a signficant role. The theoretical development portion of this Review was supported by the National Science Foundation under CHE-10-57875. The biological portion of this Review was funded by NIH Grant No. GM056207. The biomimetic portion was supported as part of the Center for Molecular Electro-catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  6. Hydrogen Tunneling in Enzymes and Biomimetic Models

    SciTech Connect

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2014-04-09

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a significant role. The biomimetic portion was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  7. Muon transfer from hot muonic hydrogen atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R. . Inst. de Physique); Bailey, J.M. ); Beer, G.A.; Knowles, P.E.; Mason, G.R.; Olin, A. ); Beveridge, J.L.; Marshall, G.M.; Brewer, J.H.; Forster, B.M. ); Huber, T.M. ); Kammel, P.; Zmeskal, J.

    1992-01-01

    A negative muon beam has been directed on adjacent solid layers of hydrogen and neon. Three targets differing by their deuterium concentration were investigated. Muonic hydrogen atoms can drift to the neon layer where the muon is immediately transferred. The time structure of the muonic neon X-rays follows the exponential law with a disappearance rate corresponding to the one of [mu][sup [minus]p] atoms in each target. The rates [lambda][sub pp[mu

  8. Hydrogen Impurity Defects in Rutile TiO2

    PubMed Central

    Mo, Li-Bin; Wang, Yu; Bai, Yang; Xiang, Qing-Yun; Li, Qun; Yao, Wen-Qing; Wang, Jia-Ou; Ibrahim, Kurash; Wang, Huan-Hua; Wan, Cai-Hua; Cao, Jiang-Li

    2015-01-01

    Hydrogen-related defects play crucial roles in determining physical properties of their host oxides. In this work, we report our systematic experimental and theoretical (based on density functional theory) studies of the defect states formed in hydrogenated-rutile TiO2 in gaseous H2 and atomic H. In gas-hydrogenated TiO2, the incorporated hydrogen tends to occupy the oxygen vacancy site and negatively charged. The incorporated hydrogen takes the interstitial position in atom-hydrogenated TiO2, forming a weak O-H bond with the closest oxygen ion, and becomes positive. Both states of hydrogen affect the electronic structure of TiO2 mainly through changes of Ti 3d and O 2p states instead of the direct contributions of hydrogen. The resulted electronic structures of the hydrogenated TiO2 are manifested in modifications of the electrical and optical properties that will be useful for the design of new materials capable for green energy economy. PMID:26627134

  9. Hydrogen Impurity Defects in Rutile TiO2

    NASA Astrophysics Data System (ADS)

    Mo, Li-Bin; Wang, Yu; Bai, Yang; Xiang, Qing-Yun; Li, Qun; Yao, Wen-Qing; Wang, Jia-Ou; Ibrahim, Kurash; Wang, Huan-Hua; Wan, Cai-Hua; Cao, Jiang-Li

    2015-12-01

    Hydrogen-related defects play crucial roles in determining physical properties of their host oxides. In this work, we report our systematic experimental and theoretical (based on density functional theory) studies of the defect states formed in hydrogenated-rutile TiO2 in gaseous H2 and atomic H. In gas-hydrogenated TiO2, the incorporated hydrogen tends to occupy the oxygen vacancy site and negatively charged. The incorporated hydrogen takes the interstitial position in atom-hydrogenated TiO2, forming a weak O-H bond with the closest oxygen ion, and becomes positive. Both states of hydrogen affect the electronic structure of TiO2 mainly through changes of Ti 3d and O 2p states instead of the direct contributions of hydrogen. The resulted electronic structures of the hydrogenated TiO2 are manifested in modifications of the electrical and optical properties that will be useful for the design of new materials capable for green energy economy.

  10. Negative air ions as a source of superoxide

    NASA Astrophysics Data System (ADS)

    Goldstein, Naum I.; Goldstein, Roman N.; Merzlyak, Mark N.

    1992-06-01

    The physico-chemical characteristics and possible formation mechanisms of negative air ions are considered. It was found that the products of oxygen and nitrogen negative ionization reduce ferricytochrome c and nitroblue tetrazolium, and that these reactions were inhibited by superoxide dismutase. The interaction of negatively ionized oxygen with water led to hydrogen peroxide accumulation, which was inhibited by tetranitromethane or catalase. Nitrogen ionization under these conditions caused the formation of the hydrated electron e{aq/—} and the superoxide anion O{2/—}. The data obtained indicate that the biological activity of negative air ions may be dependent on superoxide. The generation of reactive oxygen ions in the gas phase and also at a gas/water interface is described. A scheme for superoxide production under oxygen and nitrogen ionization is proposed.

  11. Investigations of negative and positive cesium ion species

    NASA Technical Reports Server (NTRS)

    Chanin, L. M.

    1978-01-01

    A direct test is provided of the hypothesis of negative ion creation at the anode or collector of a diode operating under conditions simulating a cesium thermionic converter. The experimental technique involves using direct ion sampling through the collector electrode with mass analysis using a quadrupole mass analyzer. Similar measurements are undertaken on positive ions extracted through the emitter electrode. Measurements were made on a variety of gases including pure cesium, helium-cesium mixtures and cesium-hydrogen as well as cesium-xenon mixtures. The gas additive was used primarily to aid in understanding the negative ion formation processes. Measurements were conducted using emitter (cathode) temperatures up to about 1000 F. The major negative ion identified through the collector was Cs(-) with minor negative ion peaks tentatively identified as H(-), H2(-), H3(-), He(-) and a mass 66. Positive ions detected were believed to be Cs(+), Cs2(+) and Cs3(+).

  12. Hydrogen Data Book from the Hydrogen Analysis Resource Center

    DOE Data Explorer

    The Hydrogen Data Book contains a wide range of factual information on hydrogen and fuel cells (e.g., hydrogen properties, hydrogen production and delivery data, and information on fuel cells and fuel cell vehicles), and it also provides other data that might be useful in analyses of hydrogen infrastructure in the United States (e.g., demographic data and data on energy supply and/or infrastructure). ItÆs made available from the Hydrogen Analysis Resource Center along with a wealth of related information. The related information includes guidelines for DOE Hydrogen Program Analysis, various calculator tools, a hydrogen glossary, related websites, and analysis tools relevant to hydrogen and fuel cells. [From http://hydrogen.pnl.gov/cocoon/morf/hydrogen

  13. Measuring Hydrogen Concentrations in Metals

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1985-01-01

    Commercial corrosion-measurement system adapted to electrochemical determination of hydrogen concentrations in metals. New technique based on diffusion of hydrogen through foil specimen of metal. In sample holder, hydrogen produced on one side of foil, either by corrosion reaction or by cathodic current. Hydrogen diffused through foil removed on other side by constant anode potential, which leads to oxidation of hydrogen to water. Anode current is measure of concentration of hydrogen diffusing through foil. System used to study hydrogen uptake, hydrogen elimination by baking, effect of heat treatment, and effect of electroplating on high-strength steels.

  14. Photoelectrochemical hydrogen production

    SciTech Connect

    Rocheleau, R.; Misra, A.; Miller, E.

    1998-08-01

    A significant component of the US DOE Hydrogen Program is the development of a practical technology for the direct production of hydrogen using a renewable source of energy. High efficiency photoelectrochemical systems to produce hydrogen directly from water using sunlight as the energy source represent one of the technologies identified by DOE to meet this mission. Reactor modeling and experiments conducted at UH provide strong evidence that direct solar-to-hydrogen conversion efficiency greater than 10% can be expected using photoelectrodes fabricated from low-cost, multijunction (MJ) amorphous silicon solar cells. Solar-to-hydrogen conversion efficiencies as high as 7.8% have been achieved using a 10.3% efficient MJ amorphous silicon solar cell. Higher efficiency can be expected with the use of higher efficiency solar cells, further improvement of the thin film oxidation and reduction catalysts, and optimization of the solar cell for hydrogen production rather than electricity production. Hydrogen and oxygen catalysts developed under this project are very stable, exhibiting no measurable degradation in KOH after over 13,000 hours of operation. Additional research is needed to fully optimize the transparent, conducting coatings which will be needed for large area integrated arrays. To date, the best protection has been afforded by wide bandgap amorphous silicon carbide films.

  15. Kinetics and continuum emission of negative atomic ions in partially ionized plasmas

    NASA Technical Reports Server (NTRS)

    Soon, W. H.; Kunc, J. A.

    1991-01-01

    Kinetics and continuum emission of negative ions are studied in stationary atomic hydrogen, nitrogen, and oxygen plasmas. The intensity of the negative-ion emission was found to be neglibible when compared to those of bound-bound and free-bound emission at low and medium particle densities. However, the negative-ion continuum emission can contribute significantly in certain parts of the emission spectrum at high particle densities.

  16. Effects of partial hydrogenation on electronic transport properties in C60 molecular devices

    NASA Astrophysics Data System (ADS)

    Chen, L. N.; Cao, C.; Wu, X. Z.; Ma, S. S.; Huang, W. R.; Xu, H.

    2012-12-01

    By using nonequilibrium Green's functions in combination with the density-function theory, we investigate electronic transport properties of molecular devices with pristine and partial hydrogenation. The calculated results show that the electronic transport properties of molecular devices can be modulated by partial hydrogenation. Interestingly, our results exhibit negative differential resistance behavior in the case of the imbalance H-adsorption in C60 molecular devices under low bias. However, negative differential resistance behavior cannot be observed in the case of the balance H-adsorption. A mechanism is proposed for the hydrogenation and negative differential resistance behavior.

  17. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  18. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  19. Extremely weak hydrogen flames

    SciTech Connect

    Lecoustre, V.R.; Sunderland, P.B.; Chao, B.H.; Axelbaum, R.L.

    2010-11-15

    Hydrogen jet diffusion flames were observed near their quenching limits. These involved downward laminar flow of hydrogen from a stainless steel hypodermic tube with an inside diameter of 0.15 mm. Near their quenching limits these flames had hydrogen flow rates of 3.9 and 2.1 {mu}g/s in air and oxygen, respectively. Assuming complete combustion, the associated heat release rates are 0.46 and 0.25 W. To the authors' knowledge, these are the weakest self-sustaining steady flames ever observed. (author)

  20. Color Changing Hydrogen Sensors

    NASA Technical Reports Server (NTRS)

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  1. Biological hydrogen production

    SciTech Connect

    Benemann, J.R.

    1995-11-01

    Biological hydrogen production can be accomplished by either thermochemical (gasification) conversion of woody biomass and agricultural residues or by microbiological processes that yield hydrogen gas from organic wastes or water. Biomass gasification is a well established technology; however, the synthesis gas produced, a mixture of CO and H{sub 2}, requires a shift reaction to convert the CO to H{sub 2}. Microbiological processes can carry out this reaction more efficiently than conventional catalysts, and may be more appropriate for the relatively small-scale of biomass gasification processes. Development of a microbial shift reaction may be a near-term practical application of microbial hydrogen production.

  2. Chemochromic Hydrogen Leak Detectors

    NASA Technical Reports Server (NTRS)

    Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

    2009-01-01

    At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

  3. Molecular origin of the negative heat capacity of hydrophilic hydration

    NASA Astrophysics Data System (ADS)

    Kinoshita, Masahiro; Yoshidome, Takashi

    2009-04-01

    The hydrophobic and hydrophilic hydrations are analyzed with the emphasis on the sign of the heat capacity of hydration (HCH). The angle-dependent integral equation theory combined with a multipolar water model is employed in the analysis. The hydration entropy (HE) is decomposed into the translational and orientational parts. It is found that the orientational part governs the temperature dependence of the HE. The orientational part is further decomposed into the solute-water pair correlation component (component 1) and the water reorganization component (component 2). For hydrophilic solutes, components 1 and 2 are negative and positive, respectively. As the temperature becomes higher, component 1 increases while component 2 decreases: They make positive and negative contributions to the HCH, respectively. The strong solute-water electrostatic attractive interactions induce the distortion of water structure near the solute and the break of hydrogen bonds. As the temperature increases, the effect of the attractive interactions becomes smaller and the distortion of water structure is reduced (i.e., more hydrogen bonds are recovered with increasing temperature). The latter effect dominates, leading to negative HCH. During the heat addition the formation of hydrogen bonds, which accompanies heat generation, occurs near the solute. Consequently, the addition of the same amount of heat leads to a larger increase in the thermal energy (or equivalently, in the temperature) than in the case of pure water. The hydrophobic hydration, which is opposite to the hydrophilic hydration in many respects, is also discussed in detail.

  4. Metal-Hydrogen Phase Diagrams in the Vicinity of Melting Temperatures

    SciTech Connect

    Shapovalov, V.I.

    1999-01-06

    Hydrogen-metal interaction phenomena belong to the most exciting challenges of today's physical metallurgy and physics of solids due to the uncommon behavior of hydrogen in condensed media and to the need for understanding hydrogen's strong negative impact on properties of some high-strength steels and.alloys. The paper cites and summarizes research data on fundamental thermodynamic characteristics of hydrogen in some metals that absorb it endothermally at elevated temperatures. For a number of metal-hydrogen systems, information on some phase diagrams previously not available to the English-speaking scientific community is presented.

  5. The ENEA F-CUBE Facility: Trends in R.F. driven compact FELs and related diagnostics

    SciTech Connect

    Doria, A.; Gallerano, G.P.; Giovenale, E.

    1995-12-31

    The Frascati FEL Facility F-CUBE (FEL-Compact for User Basic Experiment) currently operates in the mm-wave region providing about 600 hrs of beam time per year to users. This FEL is a low cost compact device intended to be the first step in making the FEL a laboratory tool. It exploits some unique features like short pulses with coherent emission seeding and the dispersion properties of a waveguide resonator at {open_quotes}zero slippage{close_quotes} to provide wide band tunability. The system is presently being upgraded to extend these characteristics into the far infrared. A new NdFeB permanent magnet undulator has been built and magnetic measurements have been performed. FEL tunability in the interval from 400 to 900 pm will be provided by the variation of the undulator gap and of the gap of the planar waveguide in the resonator. Due to the short electron bunch duration coherent spontaneous emission is expected also in this wavelength range. Its effect on the FEL performance will be discussed together with a comparison of different coherent emission mechanisms, like coherent transition radiation (CTR), which can be used as a diagnostic tool.

  6. Remote hydrogen sensing techniques

    NASA Technical Reports Server (NTRS)

    Perry, Cortes L.

    1992-01-01

    The objective of this project is to evaluate remote hydrogen sensing methodologies utilizing metal oxide semi-conductor field effect transistors (MOS-FET) and mass spectrometric (MS) technologies and combinations thereof.

  7. Fiber optic hydrogen sensor

    SciTech Connect

    Butler, M.A.; Sanchez, R.; Dulleck, G.R.

    1996-05-01

    This report covers the development of fiber optic hydrogen and temperature sensors for monitoring dissolved hydrogen gas in transformer oil. The concentration of hydrogen gas is a measure of the corona and spark discharge within the transformer and reflects the state of health of the transformer. Key features of the instrument include use of palladium alloys to enhance hydrogen sensitivity, a microprocessor controlled instrument with RS-232, liquid crystal readout, and 4-20 ma. current loop interfaces. Calibration data for both sensors can be down loaded to the instrument through the RS-232 interface. This project was supported by the Technology Transfer Initiative in collaboration with J. W. Harley, Inc. through the mechanism of a cooperative research and development agreement (CRADA).

  8. Florida Hydrogen Initiative

    SciTech Connect

    Block, David L

    2013-06-30

    The Florida Hydrogen Initiative (FHI) was a research, development and demonstration hydrogen and fuel cell program. The FHI program objectives were to develop Florida?s hydrogen and fuel cell infrastructure and to assist DOE in its hydrogen and fuel cell activities The FHI program funded 12 RD&D projects as follows: Hydrogen Refueling Infrastructure and Rental Car Strategies -- L. Lines, Rollins College This project analyzes strategies for Florida's early stage adaptation of hydrogen-powered public transportation. In particular, the report investigates urban and statewide network of refueling stations and the feasibility of establishing a hydrogen rental-car fleet based in Orlando. Methanol Fuel Cell Vehicle Charging Station at Florida Atlantic University ? M. Fuchs, EnerFuel, Inc. The project objectives were to design, and demonstrate a 10 kWnet proton exchange membrane fuel cell stationary power plant operating on methanol, to achieve an electrical energy efficiency of 32% and to demonstrate transient response time of less than 3 milliseconds. Assessment of Public Understanding of the Hydrogen Economy Through Science Center Exhibits, J. Newman, Orlando Science Center The project objective was to design and build an interactive Science Center exhibit called: ?H2Now: the Great Hydrogen Xchange?. On-site Reformation of Diesel Fuel for Hydrogen Fueling Station Applications ? A. Raissi, Florida Solar Energy Center This project developed an on-demand forecourt hydrogen production technology by catalytically converting high-sulfur hydrocarbon fuels to an essentially sulfur-free gas. The removal of sulfur from reformate is critical since most catalysts used for the steam reformation have limited sulfur tolerance. Chemochromic Hydrogen Leak Detectors for Safety Monitoring ? N. Mohajeri and N. Muradov, Florida Solar Energy Center This project developed and demonstrated a cost-effective and highly selective chemochromic (visual) hydrogen leak detector for safety monitoring

  9. Hydrogen-fueled engine

    NASA Technical Reports Server (NTRS)

    Laumann, E. A.; Reynolds, R. K. (Inventor)

    1978-01-01

    A hydrogen-oxygen fueled internal combustion engine is described, which utilizes an inert gas, such as argon, as a working fluid to increase the efficiency of the engine, eliminate pollution, and facilitate operation of a closed cycle energy system. In a system where sunlight or other intermittent energy source is available to separate hydrogen and oxygen from water, the oxygen and inert gas are taken into a diesel engine into which hydrogen is injected and ignited. The exhaust is cooled so that it contains only water and the inert gas. The inert gas in the exhaust is returned to the engine for use with fresh oxygen, while the water in the exhaust is returned to the intermittent energy source for reconversion to hydrogen and oxygen.

  10. Photoelectrochemical hydrogen production

    SciTech Connect

    Rocheleau, R.E.; Miller, E.; Misra, A.

    1996-10-01

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

  11. Hydrogen chloride test set

    NASA Technical Reports Server (NTRS)

    Workman, G. L.

    1976-01-01

    Detector uses tertiary amine, which makes reaction fairly specific for relatively small highly polarized hydrogen chloride molecule. Reaction is monitored by any microbalance capable of measuring extremely small mass differences in real time.

  12. Hydrogen storage compositions

    SciTech Connect

    Li, Wen; Vajo, John J.; Cumberland, Robert W.; Liu, Ping

    2011-04-19

    Compositions for hydrogen storage and methods of making such compositions employ an alloy that exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The composition includes a ternary alloy including magnesium, boron and a metal and a metal hydride. The ternary alloy and the metal hydride are present in an amount sufficient to render the composition capable of hydrogen storage. The molar ratio of the metal to magnesium and boron in the alloy is such that the alloy exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The hydrogen storage composition is prepared by combining magnesium, boron and a metal to prepare a ternary alloy and combining the ternary alloy with a metal hydride to form the hydrogen storage composition.

  13. Preparation of hydrogen peroxide

    SciTech Connect

    Brill, W.F.

    1984-07-31

    Hydrogen peroxide is produced in a reaction between carbon monoxide, oxygen, and water in the presence of a solvent using a Group 8 noble metal as a catalyst. Especially preferred as the working solution is palladium chloride in acetone.

  14. Thin film hydrogen sensor

    DOEpatents

    Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

    1994-11-22

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

  15. Hydrogen moderator performance calculations

    SciTech Connect

    Picton, D. J.; Beynon, T. D.; Broome, T. A.

    1997-09-01

    A comparison was made between MCNP calculations and experimental measurements of the neutron spectrum from the liquid hydrogen moderator on ISIS. The calculations were performed for varying ortho/para concentrations, and demonstrated a best fit for 100% para-hydrogen. The agreement between the measured and calculated results was good below 2Å (i.e. for energies above 20 meV) but significant deviations were seen for longer wavelengths. A second study used the MCNP code for a detailed comparison of the time distributions and neutron spectra from poisoned liquid hydrogen and liquid methane moderators. The results indicate that the replacement of a liquid methane moderator with liquid hydrogen, in order to eliminate radiation damage effects, is an option which can be seriously considered. (auth)

  16. The hydrogen issue.

    PubMed

    Armaroli, Nicola; Balzani, Vincenzo

    2011-01-17

    Hydrogen is often proposed as the fuel of the future, but the transformation from the present fossil fuel economy to a hydrogen economy will need the solution of numerous complex scientific and technological issues, which will require several decades to be accomplished. Hydrogen is not an alternative fuel, but an energy carrier that has to be produced by using energy, starting from hydrogen-rich compounds. Production from gasoline or natural gas does not offer any advantage over the direct use of such fuels. Production from coal by gasification techniques with capture and sequestration of CO₂ could be an interim solution. Water splitting by artificial photosynthesis, photobiological methods based on algae, and high temperatures obtained by nuclear or concentrated solar power plants are promising approaches, but still far from practical applications. In the next decades, the development of the hydrogen economy will most likely rely on water electrolysis by using enormous amounts of electric power, which in its turn has to be generated. Producing electricity by burning fossil fuels, of course, cannot be a rational solution. Hydroelectric power can give but a very modest contribution. Therefore, it will be necessary to generate large amounts of electric power by nuclear energy of by renewable energies. A hydrogen economy based on nuclear electricity would imply the construction of thousands of fission reactors, thereby magnifying all the problems related to the use of nuclear energy (e.g., safe disposal of radioactive waste, nuclear proliferation, plant decommissioning, uranium shortage). In principle, wind, photovoltaic, and concentrated solar power have the potential to produce enormous amounts of electric power, but, except for wind, such technologies are too underdeveloped and expensive to tackle such a big task in a short period of time. A full development of a hydrogen economy needs also improvement in hydrogen storage, transportation and distribution

  17. The hydrogen issue.

    PubMed

    Armaroli, Nicola; Balzani, Vincenzo

    2011-01-17

    Hydrogen is often proposed as the fuel of the future, but the transformation from the present fossil fuel economy to a hydrogen economy will need the solution of numerous complex scientific and technological issues, which will require several decades to be accomplished. Hydrogen is not an alternative fuel, but an energy carrier that has to be produced by using energy, starting from hydrogen-rich compounds. Production from gasoline or natural gas does not offer any advantage over the direct use of such fuels. Production from coal by gasification techniques with capture and sequestration of CO₂ could be an interim solution. Water splitting by artificial photosynthesis, photobiological methods based on algae, and high temperatures obtained by nuclear or concentrated solar power plants are promising approaches, but still far from practical applications. In the next decades, the development of the hydrogen economy will most likely rely on water electrolysis by using enormous amounts of electric power, which in its turn has to be generated. Producing electricity by burning fossil fuels, of course, cannot be a rational solution. Hydroelectric power can give but a very modest contribution. Therefore, it will be necessary to generate large amounts of electric power by nuclear energy of by renewable energies. A hydrogen economy based on nuclear electricity would imply the construction of thousands of fission reactors, thereby magnifying all the problems related to the use of nuclear energy (e.g., safe disposal of radioactive waste, nuclear proliferation, plant decommissioning, uranium shortage). In principle, wind, photovoltaic, and concentrated solar power have the potential to produce enormous amounts of electric power, but, except for wind, such technologies are too underdeveloped and expensive to tackle such a big task in a short period of time. A full development of a hydrogen economy needs also improvement in hydrogen storage, transportation and distribution

  18. Hydrogen recovery process

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

    2000-01-01

    A treatment process for a hydrogen-containing off-gas stream from a refinery, petrochemical plant or the like. The process includes three separation steps: condensation, membrane separation and hydrocarbon fraction separation. The membrane separation step is characterized in that it is carried out under conditions at which the membrane exhibits a selectivity in favor of methane over hydrogen of at least about 2.5.

  19. Purdue Hydrogen Systems Laboratory

    SciTech Connect

    Jay P Gore; Robert Kramer; Timothee L Pourpoint; P. V. Ramachandran; Arvind Varma; Yuan Zheng

    2011-12-28

    The Hydrogen Systems Laboratory in a unique partnership between Purdue University's main campus in West Lafayette and the Calumet campus was established and its capabilities were enhanced towards technology demonstrators. The laboratory engaged in basic research in hydrogen production and storage and initiated engineering systems research with performance goals established as per the USDOE Hydrogen, Fuel Cells, and Infrastructure Technologies Program. In the chemical storage and recycling part of the project, we worked towards maximum recycling yield via novel chemical selection and novel recycling pathways. With the basic potential of a large hydrogen yield from AB, we used it as an example chemical but have also discovered its limitations. Further, we discovered alternate storage chemicals that appear to have advantages over AB. We improved the slurry hydrolysis approach by using advanced slurry/solution mixing techniques. We demonstrated vehicle scale aqueous and non-aqueous slurry reactors to address various engineering issues in on-board chemical hydrogen storage systems. We measured the thermal properties of raw and spent AB. Further, we conducted experiments to determine reaction mechanisms and kinetics of hydrothermolysis in hydride-rich solutions and slurries. We also developed a continuous flow reactor and a laboratory scale fuel cell power generation system. The biological hydrogen production work summarized as Task 4.0 below, included investigating optimal hydrogen production cultures for different substrates, reducing the water content in the substrate, and integrating results from vacuum tube solar collector based pre and post processing tests into an enhanced energy system model. An automated testing device was used to finalize optimal hydrogen production conditions using statistical procedures. A 3 L commercial fermentor (New Brunswick, BioFlo 115) was used to finalize testing of larger samples and to consider issues related to scale up. Efforts

  20. Cryogenic hydrogen release research.

    SciTech Connect

    LaFleur, Angela Christine

    2015-12-01

    The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  1. Hydrogen-powered flight

    NASA Technical Reports Server (NTRS)

    Smith, Timothy D.

    2005-01-01

    As the Nation moves towards a hydrogen economy the shape of aviation will change dramatically. To accommodate a switch to hydrogen the aircraft designs, propulsion, and power systems will look much different than the systems of today. Hydrogen will enable a number of new aircraft capabilities from high altitude long endurance remotely operated aircraft (HALE ROA) that will fly weeks to months without refueling to clean, zero emissions transport aircraft. Design and development of new hydrogen powered aircraft have a number of challenges which must be addressed before an operational system can become a reality. While the switch to hydrogen will be most outwardly noticeable in the aircraft designs of the future, other significant changes will be occurring in the environment. A switch to hydrogen for aircraft will completely eliminate harmful greenhouse gases such as carbon monoxide (CO), carbon dioxide (CO2), sulfur oxides (SOx), unburnt hydrocarbons and smoke. While these aircraft emissions are a small percentage of the amount produced on a daily basis, their placement in the upper atmosphere make them particularly harmful. Another troublesome gaseous emission from aircraft is nitrogen oxides (NOx) which contribute to ozone depletion in the upper atmosphere. Nitrogen oxide emissions are produced during the combustion process and are primarily a function of combustion temperature and residence time. The introduction of hydrogen to a gas turbine propulsion system will not eliminate NOx emissions; however the wide flammability range will make low NOx producing, lean burning systems feasible. A revolutionary approach to completely eliminating NOx would be to fly all electric aircraft powered by hydrogen air fuel cells. The fuel cells systems would only produce water, which could be captured on board or released in the lower altitudes. Currently fuel cell systems do not have sufficient energy densities for use in large aircraft, but the long term potential of eliminating

  2. Lokiarchaeon is hydrogen dependent.

    PubMed

    Sousa, Filipa L; Neukirchen, Sinje; Allen, John F; Lane, Nick; Martin, William F

    2016-01-01

    The nature of the host that acquired the mitochondrion at the eukaryote origin is an important microbial evolutionary issue. Modern phylogenetics indicates that the host was an archaeon. The metagenome sequence of Candidatus Lokiarchaeon has identified it as being the closest relative of the host yet known. Here, we report comparative genomic evidence indicating that Lokiarchaeon is hydrogen dependent, as one theory for the eukaryote origin-the hydrogen hypothesis-predicts for the host lineage. PMID:27572645

  3. Advanced Hydrogen Liquefaction Process

    SciTech Connect

    Schwartz, Joseph; Kromer, Brian; Neu, Ben; Jankowiak, Jerome; Barrett, Philip; Drnevich, Raymond

    2011-09-28

    The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased the understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.

  4. 24. Duplicate negative of an historic negative. 'AERIAL VIEW OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Duplicate negative of an historic negative. 'AERIAL VIEW OF AREA 'B' HOLSTON ORDNANCE WORKS.' 1944. #OCMH 4-12.2ASAV3 in Super Explosives Program RDX and Its Composition A, B, & C, Record Group No. 319, National Archives, Washington, D.C. - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  5. On Negation as Mitigation: The Case of Negative Irony

    ERIC Educational Resources Information Center

    Giora, Rachel; Fein, Ofer; Ganzi, Jonathan; Levi, Natalie Alkeslassy; Sabah, Hadas

    2005-01-01

    Four experiments support the view of negation as mitigation (Giora, Balaban, Fein, & Alkabets, 2004). They show that when irony involves some sizable gap between what is said and what is criticized (He is exceptionally bright said of an idiot), it is rated as highly ironic (Giora, 1995). A negated version of that overstatement (He is not…

  6. Intrinsic Negative Mass from Nonlinearity

    NASA Astrophysics Data System (ADS)

    Di Mei, F.; Caramazza, P.; Pierangeli, D.; Di Domenico, G.; Ilan, H.; Agranat, A. J.; Di Porto, P.; DelRe, E.

    2016-04-01

    We propose and provide experimental evidence of a mechanism able to support negative intrinsic effective mass. The idea is to use a shape-sensitive nonlinearity to change the sign of the mass in the leading linear propagation equation. Intrinsic negative-mass dynamics is reported for light beams in a ferroelectric crystal substrate, where the diffusive photorefractive nonlinearity leads to a negative-mass Schrödinger equation. The signature of inverted dynamics is the observation of beams repelled from strongly guiding integrated waveguides irrespective of wavelength and intensity and suggests shape-sensitive nonlinearity as a basic mechanism leading to intrinsic negative mass.

  7. Electrochemical hydrogen Storage Systems

    SciTech Connect

    Dr. Digby Macdonald

    2010-08-09

    As the global need for energy increases, scientists and engineers have found a possible solution by using hydrogen to power our world. Although hydrogen can be combusted as a fuel, it is considered an energy carrier for use in fuel cells wherein it is consumed (oxidized) without the production of greenhouse gases and produces electrical energy with high efficiency. Chemical storage of hydrogen involves release of hydrogen in a controlled manner from materials in which the hydrogen is covalently bound. Sodium borohydride and aminoborane are two materials given consideration as chemical hydrogen storage materials by the US Department of Energy. A very significant barrier to adoption of these materials as hydrogen carriers is their regeneration from 'spent fuel,' i.e., the material remaining after discharge of hydrogen. The U.S. Department of Energy (DOE) formed a Center of Excellence for Chemical Hydrogen Storage, and this work stems from that project. The DOE has identified boron hydrides as being the main compounds of interest as hydrogen storage materials. The various boron hydrides are then oxidized to release their hydrogen, thereby forming a 'spent fuel' in the form of a lower boron hydride or even a boron oxide. The ultimate goal of this project is to take the oxidized boron hydrides as the spent fuel and hydrogenate them back to their original form so they can be used again as a fuel. Thus this research is essentially a boron hydride recycling project. In this report, research directed at regeneration of sodium borohydride and aminoborane is described. For sodium borohydride, electrochemical reduction of boric acid and sodium metaborate (representing spent fuel) in alkaline, aqueous solution has been investigated. Similarly to literature reports (primarily patents), a variety of cathode materials were tried in these experiments. Additionally, approaches directed at overcoming electrostatic repulsion of borate anion from the cathode, not described in the

  8. Examining hydrogen transitions.

    SciTech Connect

    Plotkin, S. E.; Energy Systems

    2007-03-01

    This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.

  9. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2003-02-05

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  10. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2001-08-28

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  11. Nanostructured materials for hydrogen storage

    DOEpatents

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  12. Hydrogen Delivery Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The mission of the Hydrogen Delivery Technical Team (HDTT) is to enable the development of hydrogen delivery technologies, which will allow for fuel cell competitiveness with gasoline and hybrid technologies by achieving an as-produced, delivered, and dispensed hydrogen cost of $2-$4 per gallon of gasoline equivalent of hydrogen.

  13. Hydrogen Distribution and Delivery Infrastructure

    SciTech Connect

    2008-11-01

    This 2-page fact sheet provides a brief introduction to hydrogen delivery technologies. Intended for a non-technical audience, it explains how hydrogen is transported and delivered today, the challenges to delivering hydrogen for use as a widespread energy carrier, and the research goals for hydrogen delivery.

  14. Hydrogen Generation Via Sodium Borohydride

    NASA Astrophysics Data System (ADS)

    Mohring, Richard M.; Wu, Ying

    2003-07-01

    Along with the technological challenges associated with developing fuel cells and hydrogen burning engines, a major issue that must be addressed to ensure the ultimate success of a hydrogen economy is the ability to store and transport hydrogen effectively. Millennium Cell has developed and patented a proprietary system for storing and generating hydrogen gas called Hydrogen on Demand™. The system releases the hydrogen stored in fuel solutions of sodium borohydride as needed through an easily controllable catalytic process. The fuel itself is water-based, rich in hydrogen content, and non-flammable. It can be stored in plastic containers under no pressure. After the hydrogen from the fuel is consumed, the remaining product, sodium metaborate (chemically similar to borax), can be recycled back into fresh fuel. In this paper, an overview of the Hydrogen on Demand™ technology is presented along with data showing the performance characteristics of practical hydrogen generation systems. A brief discussion of sodium borohydride regeneration chemistry is also provided.

  15. Structural investigations of hydrogenated epitaxial graphene grown on 4H-SiC (0001)

    SciTech Connect

    Tokarczyk, M.; Kowalski, G. Stępniewski, R.; Możdżonek, M.; Strupiński, W.; Ciepielewski, P.; Borysiuk, J.

    2013-12-09

    Structural investigations of hydrogenated epitaxial graphene grown on SiC(0001) are presented. It is shown that hydrogen plays a dual role. In addition to contributing to the well-known removal of the buffer layer, it goes between the graphene planes, resulting in an increase of the interlayer spacing to 3.6 Å–3.8 Å. It is explained by the intercalation of molecular hydrogen between carbon planes, which is followed by H{sub 2} dissociation, resulting in negatively charged hydrogen atoms trapped between the graphene layers, with some addition of covalent bonding to carbon atoms. Negatively charged hydrogen may be responsible for p-doping observed in hydrogenated multilayer graphene.

  16. California Hydrogen Infrastructure Project

    SciTech Connect

    Heydorn, Edward C

    2013-03-12

    Air Products and Chemicals, Inc. has completed a comprehensive, multiyear project to demonstrate a hydrogen infrastructure in California. The specific primary objective of the project was to demonstrate a model of a real-world retail hydrogen infrastructure and acquire sufficient data within the project to assess the feasibility of achieving the nation's hydrogen infrastructure goals. The project helped to advance hydrogen station technology, including the vehicle-to-station fueling interface, through consumer experiences and feedback. By encompassing a variety of fuel cell vehicles, customer profiles and fueling experiences, this project was able to obtain a complete portrait of real market needs. The project also opened its stations to other qualified vehicle providers at the appropriate time to promote widespread use and gain even broader public understanding of a hydrogen infrastructure. The project engaged major energy companies to provide a fueling experience similar to traditional gasoline station sites to foster public acceptance of hydrogen. Work over the course of the project was focused in multiple areas. With respect to the equipment needed, technical design specifications (including both safety and operational considerations) were written, reviewed, and finalized. After finalizing individual equipment designs, complete station designs were started including process flow diagrams and systems safety reviews. Material quotes were obtained, and in some cases, depending on the project status and the lead time, equipment was placed on order and fabrication began. Consideration was given for expected vehicle usage and station capacity, standard features needed, and the ability to upgrade the station at a later date. In parallel with work on the equipment, discussions were started with various vehicle manufacturers to identify vehicle demand (short- and long-term needs). Discussions included identifying potential areas most suited for hydrogen fueling stations

  17. Hydrogen storage and generation system

    DOEpatents

    Dentinger, Paul M.; Crowell, Jeffrey A. W.

    2010-08-24

    A system for storing and generating hydrogen generally and, in particular, a system for storing and generating hydrogen for use in an H.sub.2/O.sub.2 fuel cell. The hydrogen storage system uses the beta particles from a beta particle emitting material to degrade an organic polymer material to release substantially pure hydrogen. In a preferred embodiment of the invention, beta particles from .sup.63Ni are used to release hydrogen from linear polyethylene.

  18. Nickel hydrogen bipolar battery electrode design

    NASA Technical Reports Server (NTRS)

    Puglisi, V. J.; Russell, P.; Verrier, D.; Hall, A.

    1985-01-01

    The preferred approach of the NASA development effort in nickel hydrogen battery design utilizes a bipolar plate stacking arrangement to obtain the required voltage-capacity configuration. In a bipolar stack, component designs must take into account not only the typical design considerations such as voltage, capacity and gas management, but also conductivity to the bipolar (i.e., intercell) plate. The nickel and hydrogen electrode development specifically relevant to bipolar cell operation is discussed. Nickel oxide electrodes, having variable type grids and in thicknesses up to .085 inch are being fabricated and characterized to provide a data base. A selection will be made based upon a system level tradeoff. Negative (hydrpogen) electrodes are being screened to select a high performance electrode which can function as a bipolar electrode. Present nickel hydrogen negative electrodes are not capable of conducting current through their cross-section. An electrode was tested which exhibits low charge and discharge polarization voltages and at the same time is conductive. Test data is presented.

  19. Negation in the Chaamling Language.

    ERIC Educational Resources Information Center

    Rai, Vishnu S.

    This paper examines the different ways of forming negative sentences in the Chaamling language, an indigenous language spoken in the eastern, hilly districts of Nepal. It explains that negation, or negativization, in the Chaamling language is done with the help of affixation. In imperative sentences, the prefix mi- is added to the verb, which is…

  20. Be Aware of Negative Reinforcement.

    ERIC Educational Resources Information Center

    Cipani, Ennio C.

    1995-01-01

    This article examines the concept of negative reinforcement in relation to the maintenance of off-task and disruptive behaviors in classrooms. Suggestions are given for determining whether negative reinforcement (in the form of escape from the instructional task) or teacher attention is maintaining the behavior. Suggestions for making tasks less…

  1. Infective endocarditis with negative blood culture and negative echocardiographic findings.

    PubMed

    Sumatani, Izumi; Kagiyama, Nobuyuki; Saito, Chie; Makanae, Masaki; Kanetsuna, Hideo; Ahn, Kenta; Mizukami, Akira; Hashimoto, Yuji

    2015-06-01

    A 61-year-old male presented with fever. He had a history of aortic valve replacement, and infective endocarditis was suspected. The transthoracic and transesophageal echocardiography on admission could not detect vegetation, and all blood cultures obtained were negative. We concluded that infective endocarditis was not likely. However, repeated echocardiography revealed paravalvular regurgitation and paravalvular abscess. Serum antibody testing for Bartonella henselae was positive, leading to the diagnosis of blood culture-negative endocarditis. Even when blood cultures and echocardiography were negative on initial examination, careful history-taking, blood tests accounting for these pathogens, and repeated echocardiography are crucial for diagnosis.

  2. Experimental investigation of hydrogen peroxide RF plasmas

    NASA Astrophysics Data System (ADS)

    Barni, R.; Decina, A.; Zanini, S.; D'Orazio, A.; Riccardi, C.

    2016-04-01

    This work reports a detailed experimental study of the plasma properties in low pressure RF discharges in hydrogen peroxide and a comparison with argon under the same operating conditions. H2O2 plasmas have been proposed for sterilization purposes. Electrical properties of the discharge were shown to be similar, as for the RF and DC voltages of the driving electrode. Bulk plasma volume remains stable, concentrated in an almost cylindrical region between the two facing electrodes. It was found that the electron temperature is almost uniform across the plasma and independent of the power level. This is higher than in argon discharges: T e  =  4.6  ±  0.9 eV versus T e  =  3.3  ±  1.1 eV. The plasma density increases almost linearly with the power level and a substantial negative ion component has been ruled out in hydrogen peroxide. Dissociation in the plasma gas phase was revealed by atomic hydrogen and hydroxyl radical emission in the discharge spectra. Emission from hydroxyl and atomic oxygen demonstrates that oxidizing radicals are produced by hydrogen peroxide discharges, revealing its usefulness for plasma processing other than sterilization, for instance to increase polymer film surface energy. On the other hand, argon could be considered as a candidate for the sterilization purposes due to the intense production of UV radiation.

  3. Safe Use of Hydrogen and Hydrogen Systems

    NASA Technical Reports Server (NTRS)

    Maes, Miguel

    2006-01-01

    This is a viewgraph presentation that is a course for teaching the safe use of hydrogen. The objectives of the course are 1. To familiarize the student with H2 safety properties 2. To enable the identification, evaluations and addressing of H2 system hazards 3. To teach: a. Safe practices for, b. Design, c. Materials selection, d. H2 system operation, e. Physical principles and empirical observations on which these safe practices are based, f. How to respond to emergency situations involving H2, g How to visualize safety concepts through in-class exercises, h. Identify numerous parameters important to H2 safety.

  4. Hydrogen peroxide poisoning.

    PubMed

    Watt, Barbara E; Proudfoot, Alex T; Vale, J Allister

    2004-01-01

    Hydrogen peroxide is an oxidising agent that is used in a number of household products, including general-purpose disinfectants, chlorine-free bleaches, fabric stain removers, contact lens disinfectants and hair dyes, and it is a component of some tooth whitening products. In industry, the principal use of hydrogen peroxide is as a bleaching agent in the manufacture of paper and pulp. Hydrogen peroxide has been employed medicinally for wound irrigation and for the sterilisation of ophthalmic and endoscopic instruments. Hydrogen peroxide causes toxicity via three main mechanisms: corrosive damage, oxygen gas formation and lipid peroxidation. Concentrated hydrogen peroxide is caustic and exposure may result in local tissue damage. Ingestion of concentrated (>35%) hydrogen peroxide can also result in the generation of substantial volumes of oxygen. Where the amount of oxygen evolved exceeds its maximum solubility in blood, venous or arterial gas embolism may occur. The mechanism of CNS damage is thought to be arterial gas embolisation with subsequent brain infarction. Rapid generation of oxygen in closed body cavities can also cause mechanical distension and there is potential for the rupture of the hollow viscus secondary to oxygen liberation. In addition, intravascular foaming following absorption can seriously impede right ventricular output and produce complete loss of cardiac output. Hydrogen peroxide can also exert a direct cytotoxic effect via lipid peroxidation. Ingestion of hydrogen peroxide may cause irritation of the gastrointestinal tract with nausea, vomiting, haematemesis and foaming at the mouth; the foam may obstruct the respiratory tract or result in pulmonary aspiration. Painful gastric distension and belching may be caused by the liberation of large volumes of oxygen in the stomach. Blistering of the mucosae and oropharyngeal burns are common following ingestion of concentrated solutions, and laryngospasm and haemorrhagic gastritis have been

  5. Reversible Chemochromic Hydrogen Detectors

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Florida Solar Energy Center (FSEC), affiliated with the University of Central Florida, has invented a reversible pigment that changes from light beige to blue when exposed to hydrogen and back to light beige when exposed to atmospheric oxygen. In laboratory and environmental studies, the FSEC pigment in its tape form failed to change color adequately when exposed to hydrogen after one day of exposure at Kennedy Space Center's Beach Corrosion Test Facility. The reversible hydrogen-detecting tape also lost its ability to change color after being placed in an environmental chamber at 45 C for one day. The first attempts at extruding the reversible pigment into various polymers were unsuccessful because of the pigment's poor thermal stability. The goal of this project was to formulate a pigment with improved thermal and environmental stability for extrusion into a variety of appropriate polymer matrices. The formulation of the reversible hydrogen-detecting pigment was modified by removing one reagent and chemically modifying the hydrogen sensitive ingredient. This was intended to improve the hydrophobicity of the pigment and alter the thermal degradation mechanism.

  6. Hydrogen Contractors Meeting

    SciTech Connect

    Fitzsimmons, Tim

    2006-05-16

    This volume highlights the scientific content of the 2006 Hydrogen Contractors Meeting sponsored by the Division of Materials Sciences and Engineering (DMS&E) on behalf of the Office of Basic Energy Sciences (BES) of the U. S. Department of Energy (DOE). Hydrogen Contractors Meeting held from May 16-19, 2006 at the Crystal Gateway Marriott Hotel Arlington, Virginia. This meeting is the second in a series of research theme-based Contractors Meetings sponsored by DMS&E held in conjunction with our counterparts in the Office of Energy Efficiency and Renewable Energy (EERE) and the first with the Hydrogen, Fuel Cells and Infrastructure Technologies Program. The focus of this year’s meeting is BES funded fundamental research underpinning advancement of hydrogen storage. The major goals of these research efforts are the development of a fundamental scientific base in terms of new concepts, theories and computational tools; new characterization capabilities; and new materials that could be used or mimicked in advancing capabilities for hydrogen storage.

  7. Hot Hydrogen Test Facility

    SciTech Connect

    W. David Swank

    2007-02-01

    The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISp. This quantity is proportional to the square root of the propellant’s absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500°C hydrogen flowing at 1500 liters per minute. The facility is intended to test non-uranium containing materials and therefore is particularly suited for testing potential cladding and coating materials. In this first installment the facility is described. Automated Data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

  8. Hot Hydrogen Test Facility

    SciTech Connect

    Swank, W. David; Carmack, Jon; Werner, James E.; Pink, Robert J.; Haggard, DeLon C.; Johnson, Ryan

    2007-01-30

    The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISP. This quantity is proportional to the square root of the propellant's absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500 deg. C hydrogen flowing at 1500 liters per minute. The facility is intended to test low activity uranium containing materials but is also suited for testing cladding and coating materials. In this first installment the facility is described. Automated data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

  9. Hydrogen-Selective Membrane

    DOEpatents

    Collins, John P.; Way, J. Douglas

    1995-09-19

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 .mu.m but typically less than about 20 .mu.m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m.sup.2.s at a temperature of greater than about 500.degree. C. and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500.degree. C. and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400.degree. C. and less than about 1000.degree. C. before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process.

  10. Hydrogen-selective membrane

    DOEpatents

    Collins, J.P.; Way, J.D.

    1995-09-19

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2}s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

  11. Hydrogen-selective membrane

    DOEpatents

    Collins, J.P.; Way, J.D.

    1997-07-29

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2} s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

  12. Hydrogen-selective membrane

    DOEpatents

    Collins, John P.; Way, J. Douglas

    1997-01-01

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 .mu.m but typically less than about 20 .mu.m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m.sup.2. s at a temperature of greater than about 500.degree. C. and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500.degree. C. and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400.degree. C. and less than about 1000.degree. C. before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process.

  13. Magnetic liquefier for hydrogen

    SciTech Connect

    1992-12-31

    This document summarizes work done at the Astronautics Technology Center of the Astronautics Corporation of America (ACA) in Phase 1 of a four phase program leading to the development of a magnetic liquefier for hydrogen. The project involves the design, fabrication, installation, and operation of a hydrogen liquefier providing significantly reduced capital and operating costs, compared to present liquefiers. To achieve this goal, magnetic refrigeration, a recently developed, highly efficient refrigeration technology, will be used for the liquefaction process. Phase 1 project tasks included liquefier conceptual design and analysis, preliminary design of promising configurations, design selection, and detailed design of the selected design. Fabrication drawings and vendor specifications for the selected design were completed during detailed design. The design of a subscale, demonstration magnetic hydrogen liquefier represents a significant advance in liquefaction technology. The cost reductions that can be realized in hydrogen liquefaction in both the subscale and, more importantly, in the full-scale device are expected to have considerable impact on the use of liquid hydrogen in transportation, chemical, and electronic industries. The benefits to the nation from this technological advance will continue to have importance well into the 21st century.

  14. Hydrogen Optical Fiber Sensors

    SciTech Connect

    Lieberman, Robert A.; Beshay, Manal; Cordero, Steven R.

    2008-07-28

    Optically-based hydrogen sensors promise to deliver an added level of safety as hydrogen and fuel cell technologies enter the mainstream. More importantly, they offer reduced power consumption and lower cost, which are desirable for mass production applications such as automobiles and consumer appliances. This program addressed two of the major challenges previously identified in porous optrode-based optical hydrogen sensors: sensitivity to moisture (ambient humidity), and interference from the oxygen in air. Polymer coatings to inhibit moisture and oxygen were developed in conjunction with newer and novel hydrogen sensing chemistries. The results showed that it is possible to achieve sensitive hydrogen detection and rapid response with minimal interference from oxygen and humidity. As a result of this work, a new and more exciting avenue of investigation was developed: the elimination of the porous optrode and deposition of the sensor chemistry directly into the polymer film. Initial results have been promising, and open up a wider range of potential applications from extended optical fiber sensing networks, to simple plastic "stickers" for use around the home and office.

  15. Photobiological production of hydrogen

    NASA Astrophysics Data System (ADS)

    Weaver, P. F.; Lien, S.; Seibert, M.

    1980-01-01

    This literature survey of photobiological hydrogen production covers the period from its discovery in relatively pure cultures during the early 1930s through 1978. The focus is hydrogen production by phototrophic organisms (and their components) which occurs at the expense of light energy and electron-donating substrates. The survey covers the major contributions in the area; however, in many cases, space has limited the degree of detail provided. Among the topics included is a brief historical overview of hydrogen metabolism in photosynthetic bacteria, eucaryotic algae, and cyanobacteria (blue-green algae). The primary enzyme systems, including hydrogenase and nitrogenase, are discussed along with the manner in which they are coupled to electron transport and the primary photochemistry of photosynthesis. A number of in vivo and in vitro photobiological hydrogen evolving schemes including photosynthetic bacterial, green algal, cyanobacterial, two-stage, and cell-free systems are examined in some detail. The remainder of the review discusses specific technical problem areas that currently limit the yield and duration of many of the systems and research that might lead to progress in these specific areas. The final section outlines, in broadest terms, future research directions necessary to these specific areas. The final section outlines, in broadest terms, future research directions necessary to develop practical photobiological hydrogen-producing systems. Both whole cell (near- to mid-term) and cell-free (long-term) systems should be emphasized. Photosynthetic bacteria currently show the most promise for near-term applied systems.

  16. Three chamber negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

    1985-01-01

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

  17. Isotropic Negative Thermal Expansion Metamaterials.

    PubMed

    Wu, Lingling; Li, Bo; Zhou, Ji

    2016-07-13

    Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale.

  18. The Reality of Negative Refraction

    NASA Astrophysics Data System (ADS)

    Smith, David

    2004-03-01

    Negative refraction, a phenomenon first hypothesized by Victor Veselago in 1968 to occur in materials whose permittivity and permeability are simultaneously negative, has now been confirmed in several independent studies. These experiments demonstrate that it is indeed possible to design and fabricate an artificial material - now known as a "metamaterial" - having an index-of-refraction that is negative over some finite band of frequencies. The positive confirmations of the phenomenon of negative refraction represent an important first step. As applications are considered that take advantage of negative index materials, the ability to meet the needed specifications is the next step, since the viability of applications is ultimately tied to the quality, reproducibility and cost of the underlying materials. Some of the more striking or exotic wave propagation behavior predicted to occur in negative index materials, such as reflectionless compact lenses, near-field refocusing, "perfect" lensing, phase compensation and novel wave-guiding phenomena - place challenging demands on the material parameters. In this talk, I will discuss our efforts to fabricate and characterize negative index metamaterials, and how the current material limitations impact a variety of proposed applications.

  19. Isotropic Negative Thermal Expansion Metamaterials.

    PubMed

    Wu, Lingling; Li, Bo; Zhou, Ji

    2016-07-13

    Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale. PMID:27333052

  20. Hydrogen production from carbonaceous material

    DOEpatents

    Lackner, Klaus S.; Ziock, Hans J.; Harrison, Douglas P.

    2004-09-14

    Hydrogen is produced from solid or liquid carbon-containing fuels in a two-step process. The fuel is gasified with hydrogen in a hydrogenation reaction to produce a methane-rich gaseous reaction product, which is then reacted with water and calcium oxide in a hydrogen production and carbonation reaction to produce hydrogen and calcium carbonate. The calcium carbonate may be continuously removed from the hydrogen production and carbonation reaction zone and calcined to regenerate calcium oxide, which may be reintroduced into the hydrogen production and carbonation reaction zone. Hydrogen produced in the hydrogen production and carbonation reaction is more than sufficient both to provide the energy necessary for the calcination reaction and also to sustain the hydrogenation of the coal in the gasification reaction. The excess hydrogen is available for energy production or other purposes. Substantially all of the carbon introduced as fuel ultimately emerges from the invention process in a stream of substantially pure carbon dioxide. The water necessary for the hydrogen production and carbonation reaction may be introduced into both the gasification and hydrogen production and carbonation reactions, and allocated so as transfer the exothermic heat of reaction of the gasification reaction to the endothermic hydrogen production and carbonation reaction.

  1. Acoustical Imaging with Negative Refraction

    NASA Astrophysics Data System (ADS)

    Gan, W. S.

    It is well known that the resolution limit of acoustical images is limited by diffraction to λ/2 where λ is the sound wavelength. Negative refraction proposed by Veselago in 1968 shows possibility of defeating the diffraction limit. His work is for electromagnetic waves. Recently it has been shown experimentally that negative refraction can be achieved for both electromagnetic waves and sound waves by using photonic crystals and phononic crystals respectively. John Pendry proposed the concept of `perfect lens' using negative refraction for electromagnetic waves. In this paper, we propose a `perfect lens' for sound waves and an acoustical imaging system incorporating the `perfect lens' is also outlined

  2. Tunable acoustic double negativity metamaterial.

    PubMed

    Liang, Z; Willatzen, M; Li, J; Christensen, J

    2012-01-01

    Man-made composite materials called "metamaterials" allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative. PMID:23152948

  3. Melaminium hydrogen malonate

    PubMed Central

    Froschauer, Barbara; Weil, Matthias

    2012-01-01

    The melaminium (2,4,6-triamino-1,3,5-triazin-1-ium) cation in the title compound, C3H7N6 +·C3H3O4 −, is essentially planar, with a r.m.s. deviation of the non-H atoms of 0.0085 Å. Extensive hydrogen bonding of the types N—H⋯N and N—H⋯O between cations and cations and between cations and hydrogen malonate (2-carb­oxy­ethano­ate) anions leads to the formation of supra­molecular layers parallel to (1-2-1). An intra­molecular O—H⋯O hydrogen bond in the single deprotonated malonate anion also occurs. PMID:22904984

  4. High-energy Physics with Hydrogen Bubble Chambers

    DOE R&D Accomplishments Database

    Alvarez, L. W.

    1958-03-07

    Recent experience with liquid hydrogen bubble chambers of 25 and 40 cm dia. in high-energy physics experiments is discussed. Experiments described are: interactions of K{sup -} mesons with protons, interactions of antiprotons with protons, catalysis of nuclear fusion reactions by muons, and production and decay of hyperons from negative pions. (W.D.M.)

  5. Hydrogen: Fueling the Future

    SciTech Connect

    Leisch, Jennifer

    2007-02-27

    As our dependence on foreign oil increases and concerns about global climate change rise, the need to develop sustainable energy technologies is becoming increasingly significant. Worldwide energy consumption is expected to double by the year 2050, as will carbon emissions along with it. This increase in emissions is a product of an ever-increasing demand for energy, and a corresponding rise in the combustion of carbon containing fossil fuels such as coal, petroleum, and natural gas. Undisputable scientific evidence indicates significant changes in the global climate have occurred in recent years. Impacts of climate change and the resulting atmospheric warming are extensive, and know no political or geographic boundaries. These far-reaching effects will be manifested as environmental, economic, socioeconomic, and geopolitical issues. Offsetting the projected increase in fossil energy use with renewable energy production will require large increases in renewable energy systems, as well as the ability to store and transport clean domestic fuels. Storage and transport of electricity generated from intermittent resources such as wind and solar is central to the widespread use of renewable energy technologies. Hydrogen created from water electrolysis is an option for energy storage and transport, and represents a pollution-free source of fuel when generated using renewable electricity. The conversion of chemical to electrical energy using fuel cells provides a high efficiency, carbon-free power source. Hydrogen serves to blur the line between stationary and mobile power applications, as it can be used as both a transportation fuel and for stationary electricity generation, with the possibility of a distributed generation energy infrastructure. Hydrogen and fuel cell technologies will be presented as possible pollution-free solutions to present and future energy concerns. Recent hydrogen-related research at SLAC in hydrogen production, fuel cell catalysis, and hydrogen

  6. Hydrogen vehicle fueling station

    SciTech Connect

    Daney, D.E.; Edeskuty, F.J.; Daugherty, M.A.

    1995-09-01

    Hydrogen fueling stations are an essential element in the practical application of hydrogen as a vehicle fuel, and a number of issues such as safety, efficiency, design, and operating procedures can only be accurately addressed by a practical demonstration. Regardless of whether the vehicle is powered by an internal combustion engine or fuel cell, or whether the vehicle has a liquid or gaseous fuel tank, the fueling station is a critical technology which is the link between the local storage facility and the vehicle. Because most merchant hydrogen delivered in the US today (and in the near future) is in liquid form due to the overall economics of production and delivery, we believe a practical refueling station should be designed to receive liquid. Systems studies confirm this assumption for stations fueling up to about 300 vehicles. Our fueling station, aimed at refueling fleet vehicles, will receive hydrogen as a liquid and dispense it as either liquid, high pressure gas, or low pressure gas. Thus, it can refuel any of the three types of tanks proposed for hydrogen-powered vehicles -- liquid, gaseous, or hydride. The paper discusses the fueling station design. Results of a numerical model of liquid hydrogen vehicle tank filling, with emphasis on no vent filling, are presented to illustrate the usefulness of the model as a design tool. Results of our vehicle performance model illustrate our thesis that it is too early to judge what the preferred method of on-board vehicle fuel storage will be in practice -- thus our decision to accommodate all three methods.

  7. Thin film hydrogen sensor

    DOEpatents

    Cheng, Y.T.; Poli, A.A.; Meltser, M.A.

    1999-03-23

    A thin film hydrogen sensor includes a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end. 5 figs.

  8. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Rupe, J. H.; Kushida, R. O. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture and igniting the mixture to provide hot combustion gases by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

  9. The hydrogen hybrid option

    SciTech Connect

    Smith, J.R.

    1993-10-15

    The energy efficiency of various piston engine options for series hybrid automobiles are compared with conventional, battery powered electric, and proton exchange membrane (PEM) fuel cell hybrid automobiles. Gasoline, compressed natural gas (CNG), and hydrogen are considered for these hybrids. The engine and fuel comparisons are done on a basis of equal vehicle weight, drag, and rolling resistance. The relative emissions of these various fueled vehicle options are also presented. It is concluded that a highly optimized, hydrogen fueled, piston engine, series electric hybrid automobile will have efficiency comparable to a similar fuel cell hybrid automobile and will have fewer total emissions than the battery powered vehicle, even without a catalyst.

  10. Hydrogen peroxide catalytic decomposition

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2010-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

  11. Thin film hydrogen sensor

    DOEpatents

    Cheng, Yang-Tse; Poli, Andrea A.; Meltser, Mark Alexander

    1999-01-01

    A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

  12. Reduced hydrogen cadmium plating

    SciTech Connect

    Hoeller, T.; Ross, L. ); Varma, R. ); Agarwala, V.S. )

    1991-01-01

    This paper demonstrates the advantages of using a periodic reverse pulse plating method, incorporating a fast cathodic pulse which is separated from the subsequent anodic/cathodic pulses by a long rest period in producing silvery cadmium coatings on steel from aqueous fluoroborate electrolyte. Also, the deposition obtained by combination of pulse currents and turbulent electrolyte flow system (forced convection of electrolyte, Re {approximately} 20-25,000) result in a near hydrogen-free electrodeposition of fine- grained cadmium. This is confirmed by the determination of diffusible hydrogen by the electrochemical (Barnach Electrode) method.

  13. NREL's Hydrogen Program

    SciTech Connect

    2011-01-01

    The research and development taking place today at the National Renewable Energy Laboratory (NREL) is paving the way for nature's most plentiful element—hydrogen—to power the next generation. NREL researchers are working to unlock the potential of hydrogen and to advance the fuel cell technologies that will power the automobiles, equipment, and buildings of tomorrow. Hydrogen and fuel cells are a fundamental part of the broader portfolio of renewable technologies that are moving our nation toward its goals of energy independence and sustainability.

  14. Hydrogen environment embrittlement of metals

    NASA Technical Reports Server (NTRS)

    Jewett, R. P.; Walter, R. J.; Chandler, W. T.; Frohmberg, R. P.

    1973-01-01

    Hydrogen environment embrittlement refers to metals stressed while exposed to a hydrogen atmosphere. Tested in air, even after exposure to hydrogen under pressure, this effect is not observed on similar specimens. Much high purity hydrogen is prepared by evaporation of liquid hydrogen, and thus has low levels for potential impurities which could otherwise inhibit or poison the absorbent reactions that are involved. High strength steels and nickel-base allows are rated as showing extreme embrittlement; aluminum alloys and the austenitic stainless steels, as well as copper, have negligible susceptibility to this phenomenon. The cracking that occurs appears to be a surface phenomenon, is unlike that of internal hydrogen embrittlement.

  15. Polyhydride complexes for hydrogen storage

    SciTech Connect

    Jensen, C.M.

    1995-09-01

    Polyhydride metal complexes are being developed for application in hydrogen storage. Efforts have focused on developing complexes with improved available hydrogen weight percentages. We have explored the possibility that complexes containing aromatic hydrocarbon ligands could store hydrogen at both the metal center and in the ligands. We have synthesized novel indenyl hydride complexes and explored their reactivity with hydrogen. The reversible hydrogenation of [IrH{sub 3}(PPh{sub 3})({eta}{sup 5}-C{sub 10}H{sub 7})]{sup +} has been achieved. While attempting to prepare {eta}{sup 6}-tetrahydronaphthalene complexes, we discovered that certain polyhydride complexes catalyze both the hydrogenation and dehydrogenation of tetrahydronaphthalene.

  16. Hydrogen production from microbial strains

    DOEpatents

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  17. [Negative pressure therapy in traumatology].

    PubMed

    Ali, Mazen

    2014-01-01

    The treatment of complex wounds in traumatology is a source of concern for nurses. Negative pressure therapy constitutes a solution for difficult-to-treat situations in the framework of open fractures and loss of limb tissue.

  18. Piezoelectric enhancement under negative pressure

    PubMed Central

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-01-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones. PMID:27396411

  19. Piezoelectric enhancement under negative pressure.

    PubMed

    Kvasov, Alexander; McGilly, Leo J; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S; Sluka, Tomas; Tagantsev, Alexander K; Setter, Nava

    2016-01-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones. PMID:27396411

  20. Adjective Metaphors Evoke Negative Meanings

    PubMed Central

    Sakamoto, Maki; Utsumi, Akira

    2014-01-01

    Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1) adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2) although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3) negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities. PMID:24586480

  1. Piezoelectric enhancement under negative pressure.

    PubMed

    Kvasov, Alexander; McGilly, Leo J; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S; Sluka, Tomas; Tagantsev, Alexander K; Setter, Nava

    2016-07-11

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  2. Adjective metaphors evoke negative meanings.

    PubMed

    Sakamoto, Maki; Utsumi, Akira

    2014-01-01

    Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1) adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2) although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3) negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities.

  3. Piezoelectric enhancement under negative pressure

    NASA Astrophysics Data System (ADS)

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-07-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  4. Hydrogen bond and halogen bond inside the carbon nanotube

    NASA Astrophysics Data System (ADS)

    Wang, Weizhou; Wang, Donglai; Zhang, Yu; Ji, Baoming; Tian, Anmin

    2011-02-01

    The hydrogen bond and halogen bond inside the open-ended single-walled carbon nanotubes have been investigated theoretically employing the newly developed density functional M06 with the suitable basis set and the natural bond orbital analysis. Comparing with the hydrogen or halogen bond in the gas phase, we find that the strength of the hydrogen or halogen bond inside the carbon nanotube will become weaker if there is a larger intramolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom donor to the antibonding orbital of the X-H or X-Hal bond involved in the formation of the hydrogen or halogen bond and will become stronger if there is a larger intermolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom acceptor to the antibonding orbital of the X-H or X-Hal bond. According to the analysis of the molecular electrostatic potential of the carbon nanotube, the driving force for the electron-density transfer is found to be the negative electric field formed in the carbon nanotube inner phase. Our results also show that the X-H bond involved in the formation of the hydrogen bond and the X-Hal bond involved in the formation of the halogen bond are all elongated when encapsulating the hydrogen bond and halogen bond within the carbon nanotube, so the carbon nanotube confinement may change the blue-shifting hydrogen bond and the blue-shifting halogen bond into the red-shifting hydrogen bond and the red-shifting halogen bond. The possibility to replace the all electron nanotube-confined calculation by the simple polarizable continuum model is also evaluated.

  5. Microbial detection method based on sensing molecular hydrogen

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.; Stoner, G. E.; Boykin, E. H.

    1974-01-01

    A simple method for detecting bacteria, based on the time of hydrogen evolution, was developed and tested against various members of the Enterobacteriaceae group. The test system consisted of (1) two electrodes, platinum and a reference electrode, (2) a buffer amplifier, and (3) a strip-chart recorder. Hydrogen evolution was measured by an increase in voltage in the negative (cathodic) direction. A linear relationship was established between inoculum size and the time hydrogen was detected (lag period). Lag times ranged from 1 h for 1 million cells/ml to 7 h for 1 cell/ml. For each 10-fold decrease in inoculum, length of the lag period increased 60 to 70 min. Based on the linear relationship between inoculum and lag period, these results indicate the potential application of the hydrogen-sensing method for rapidly detecting coliforms and other gas-producing microorganisms in a variety of clinical, food, and other samples.

  6. Regional Consumer Hydrogen Demand and Optimal Hydrogen Refueling Station Siting

    SciTech Connect

    Melendez, M.; Milbrandt, A.

    2008-04-01

    Using a GIS approach to spatially analyze key attributes affecting hydrogen market transformation, this study proposes hypothetical hydrogen refueling station locations in select subregions to demonstrate a method for determining station locations based on geographic criteria.

  7. [Negative symptoms and cerebral imaging].

    PubMed

    Kaladjian, A; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    A number of neuroanatomical and neurofonctional abnormalities have been evidenced by cerebral imaging studies in patients suffering from schizophrenia. Nevertheless, those specifically associated with the negative symptoms of this disease are still insufficiently known. This work is a review of selected studies that have assessed the brain correlates of negative symptoms in schizophrenia. Approaches using structural imaging have highlighted reduction of gray matter density or cortical thickness associated with negative symptoms, which is rather sparsely distributed within the frontal and temporal regions, localized nevertheless more particularly in the frontal medial and orbitofrontal areas, as well as the amygdalo-hippocampic complex. These deficits are concurrent with a loss of integrity of the principal paths of white matter tracts between frontal and limbic regions. On the other hand, neurofonctional abnormalities associated with negative symptoms involve especially the frontal areas and limbic striatum. A disturbed functioning within the fronto-striatal loops, related to a striatal dopaminergic deficit, may represent a potential explanatory hypothesis of the negative symptoms of schizophrenia, as suggested by studies using Positron Emission Tomography on this topic or neuroimaging studies on the effects of antipsychotics. A better identification of the cerebral abnormalities associated with the negative dimension of schizophrenia, with regard to the lateralization of these abnormalities or to their changes during the course of the disease, could offer new therapeutic modalities for the treatment of this dimension which, until now, remains few responsive to conventional pharmacological treatments. PMID:26776387

  8. Negative refraction in molybdenum disulfide.

    PubMed

    Wang, Wenhui; Cui, Xudong; Yang, Erchan; Fan, Quanping; Xiang, Bin

    2015-08-24

    Recently, negative refractions have been demonstrated in uniaxial crystals with no necessary of negative permittivity and permeability. However, the small anisotropy parameterγin the uniaxial crystals limits the negative refraction occurrence only in a small range of the incident light angle, retarding its practical applications. In this paper, we report negative refraction induced by a pronounced anisotropic behavior in the bulk MoS(2). Using the first-principles, the dielectric function and refractive index calculations confirm a uniaxial trait of MoS(2) with a calculated anisotropy parameterγlarger than 2.5 in the entire range of visible wavelength. The critical incident angle to trigger a negative refraction in the bulk MoS(2) is calculated up to 90°. The finite-difference time-domain simulations prove that the incident light with a density of 59.5% can be negatively refracted in a MoS(2) slab with a thickness of 0.1 µm. Our results open up a new pathway for MoS(2)-like materials to a novel field of optical integration.

  9. Hydrogen from biomass: state of the art and research challenges

    SciTech Connect

    Milne, Thomas A; Elam, Carolyn C; Evans, Robert J

    2002-02-01

    The report was prepared for the International Energy Agency (IEA) Agreement on the Production and Utilization of Hydrogen, Task 16, Hydrogen from Carbon-Containing Materials. Hydrogen's share in the energy market is increasing with the implementation of fuel cell systems and the growing demand for zero-emission fuels. Hydrogen production will need to keep pace with this growing market. In the near term, increased production will likely be met by conventional technologies, such as natural gas reforming. In these processes, the carbon is converted to CO2 and released to the atmosphere. However, with the growing concern about global climate change, alternatives to the atmospheric release of CO2 are being investigated. Sequestration of the CO2 is an option that could provide a viable near-term solution. Reducing the demand on fossil resources remains a significant concern for many nations. Renewable-based processes like solar- or wind-driven electrolysis and photobiological water splitting hold great promise for clean hydrogen production; however, advances must still be made before these technologies can be economically competitive. For the near-and mid-term, generating hydrogen from biomass may be the more practical and viable, renewable and potentially carbon-neutral (or even carbon-negative in conjunction with sequestration) option. Recently, the IEA Hydrogen Agreement launched a new task to bring together international experts to investigate some of these near- and mid-term options for producing hydrogen with reduced environmental impacts. This review of the state of the art of hydrogen production from biomass was prepared to facilitate in the planning of work that should be done to achieve the goal of near-term hydrogen energy systems. The relevant technologies that convert biomass to hydrogen, with emphasis on thermochemical routes are described. In evaluating the viability of the conversion routes, each must be put in the context of the availability of

  10. Study of hydrogen slush-hydrogen gel utilization

    NASA Technical Reports Server (NTRS)

    Keller, C. W.

    1967-01-01

    Study of hydrogen slush-hydrogen gel utilization is presented in two volume publication. The first volume contains the physical and thermal property data for hydrogen used in the study. In the second volume, details of the technical effort are presented including parametric analysis of effects on vehicle systems.

  11. Gas controlled hydrogen fermentation.

    PubMed

    Bastidas-Oyanedel, Juan-Rodrigo; Mohd-Zaki, Zuhaida; Zeng, Raymond J; Bernet, Nicolas; Pratt, Steven; Steyer, Jean-Philippe; Batstone, Damien John

    2012-04-01

    Acidogenic fermentation is an anaerobic process of double purpose, while treating organic residues it produces chemical compounds, such as hydrogen, ethanol and organic acids. Therefore, acidogenic fermentation arises as an attractive biotechnology process towards the biorefinery concept. Moreover, this process does not need sterile operating conditions and works under a wide range of pH. Changes of operating conditions produce metabolic shifts, inducing variability on acidogenic product yield. To induce those changes, experiments, based on reactor headspace N(2)-flushing (gas phase), were designed. A major result was the hydrogen yield increase from 1 to 3.25±0.4 ( [Formula: see text] ) at pH 4.5 and N(2)-flushing of 58.4 (L·d(-1)). This yield is close to the theoretical acidogenic value (4 [Formula: see text] ). The mechanisms that explain this increase on hydrogen yield shifts are related to the thermodynamics of three metabolic reactions: lactate hydrogenase, NADH hydrogenase and homoacetogenesis, which are affected by the low hydrogen partial pressures. PMID:22342590

  12. Resistive hydrogen sensing element

    DOEpatents

    Lauf, Robert J.

    2000-01-01

    Systems and methods are described for providing a hydrogen sensing element with a more robust exposed metallization by application of a discontinuous or porous overlay to hold the metallization firmly on the substrate. An apparatus includes: a substantially inert, electrically-insulating substrate; a first Pd containing metallization deposited upon the substrate and completely covered by a substantially hydrogen-impermeable layer so as to form a reference resistor on the substrate; a second Pd containing metallization deposited upon the substrate and at least a partially accessible to a gas to be tested, so as to form a hydrogen-sensing resistor; a protective structure disposed upon at least a portion of the second Pd containing metallization and at least a portion of the substrate to improve the attachment of the second Pd containing metallization to the substrate while allowing the gas to contact said the second Pd containing metallization; and a resistance bridge circuit coupled to both the first and second Pd containing metallizations. The circuit determines the difference in electrical resistance between the first and second Pd containing metallizations. The hydrogen concentration in the gas may be determined. The systems and methods provide advantages because adhesion is improved without adversely effecting measurement speed or sensitivity.

  13. Experiments on hydrogen deflagration

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Iwabuchi, H.; Groethe, M.; Merilo, E.; Chiba, S.

    Deflagrations of hydrogen mixed with air have been studied in an open space and inside a shock tube to provide fundamental data needed for safety evaluations and validation of computer models. The open space tests were performed in 5.2- and 37-m 3 rectangular tents and in a 300-m 3 hemispherical tent that were filled with quiescent, homogenous mixtures ranging from 15 to 57% hydrogen by volume. The mixture was contained by a very thin plastic membrane that was cut just prior to igniting the mixture with a spark at the bottom center to prevent confinement of the mass flow. The information collected included flame front propagation monitored with ionization probes, the pressure-time histories of the resulting blast, and radiated heat obtained from thermal flux sensors. In these experiments the following results were obtained. (i) Deflagration of 30% hydrogen generated a much higher overpressure than deflagration of 9.5% natural gas. (ii) The flame propagation velocity and generated pressure were remarkably influenced by the hydrogen concentration. (iii) Turbulence caused by obstacles within the gas mixture and increasing the gas mixture volume increased the speed of the flame propagation and the overpressure. (iv) The combustion inside a tube also showed a high-speed deflagration. These results are useful to re-examine the existing codes and standards.

  14. Hydrogen isotope separation

    DOEpatents

    Bartlit, J.R.; Denton, W.H.; Sherman, R.H.

    Disclosed is a system of four cryogenic fractional distillation columns interlinked with two equilibrators for separating a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D/sub 2/, DT, T/sub 2/, and a tritium-free stream of HD for waste disposal.

  15. Hydrogen isotope separation

    DOEpatents

    Bartlit, John R.; Denton, William H.; Sherman, Robert H.

    1982-01-01

    A system of four cryogenic fractional distillation columns interlinked with two equilibrators for separating a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D.sub.2, DT, T.sub.2, and a tritium-free stream of HD for waste disposal.

  16. A Simple Hydrogen Electrode

    ERIC Educational Resources Information Center

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  17. Liquid Hydrogen: Target, Detector

    SciTech Connect

    Mulholland, G.T.; Harigel, G.G.

    2004-06-23

    In 1952 D. Glaser demonstrated that a radioactive source's radiation could boil 135 deg. C superheated-diethyl ether in a 3-mm O glass vessel and recorded bubble track growth on high-speed film in a 2-cm3 chamber. This Bubble Chamber (BC) promised improved particle track time and spatial resolution and cycling rate. Hildebrand and Nagle, U of Chicago, reported Liquid Hydrogen minimum ionizing particle boiling in August 1953. John Wood created the 3.7-cm O Liquid Hydrogen BC at LBL in January 1954. By 1959 the Lawrence Berkley Laboratory (LBL) Alvarez group's '72-inch' BC had tracks in liquid hydrogen. Within 10 years bubble chamber volumes increased by a factor of a million and spread to every laboratory with a substantial high-energy physics program. The BC, particle accelerators and special separated particle beams created a new era of High Energy Physics (HEP) experimentation. The BC became the largest most complex cryogenic installation at the world's HEP laboratories for decades. The invention and worldwide development, deployment and characteristics of these cryogenic dynamic target/detectors and related hydrogen targets are described.

  18. Chemochromic Hydrogen Sensors

    NASA Technical Reports Server (NTRS)

    Wiggins, Bryan C.

    2007-01-01

    As fossil fuel supplies decline, hydrogen is quickly becoming an increasingly important fuel source. Currently hydrogen is the prime fuel of today's space vehicles (e.g., Space Shuttle) and featured as a fuel for some prototype vehicles such as the BMW seven series model. Hydrogen is a colorless, odorless gas with a 4% lower explosive limit which makes leak detection a priority. In an effort to support the use of hydrogen, a chemochromic (color changing) sensor was developed that is robust, simple to use, and does not require active operation. It can be made into a thin tape which can be conveniently used for leak detection at flanges, valves, or outlets. Chemochromic sensors can be either reversible or irreversible; however, irreversible chemochromic sensors will be analyzed in this report. The irreversible sensor is useful during hazardous operations when personnel cannot be present. To actively monitor leaks, testing of the irreversible sensor against environmental effects was completed and results indicated this material is suitable for outdoor use in the harsh beachside environment of Kennedy Space Center. The experiments in this report will give additional results to the environmental testing by adding solid rocket booster residue as a variable. The primary motivation for these experiments is to prepare the sensors for the launch pad environment at the Kennedy Space Center. In an effort to simulate the atmosphere at the pads before and after launch, the chemochromic sensors are exposed to solid rocket residue under various conditions.

  19. Hydrogen fuel - Universal energy

    NASA Astrophysics Data System (ADS)

    Prince, A. G.; Burg, J. A.

    The technology for the production, storage, transmission, and consumption of hydrogen as a fuel is surveyed, with the physical and chemical properties of hydrogen examined as they affect its use as a fuel. Sources of hydrogen production are described including synthesis from coal or natural gas, biomass conversion, thermochemical decomposition of water, and electrolysis of water, of these only electrolysis is considered economicially and technologically feasible in the near future. Methods of production of the large quantities of electricity required for the electrolysis of sea water are explored: fossil fuels, hydroelectric plants, nuclear fission, solar energy, wind power, geothermal energy, tidal power, wave motion, electrochemical concentration cells, and finally ocean thermal energy conversion (OTEC). The wind power and OTEC are considered in detail as the most feasible approaches. Techniques for transmission (by railcar or pipeline), storage (as liquid in underwater or underground tanks, as granular metal hydride, or as cryogenic liquid), and consumption (in fuel cells in conventional power plants, for home usage, for industrial furnaces, and for cars and aircraft) are analyzed. The safety problems of hydrogen as a universal fuel are discussed, noting that they are no greater than those for conventional fuels.

  20. Hydrogen evolution: Guiding principles

    NASA Astrophysics Data System (ADS)

    Xia, Zhenhai

    2016-10-01

    Lower-cost alternatives to platinum electrocatalysts are being explored for the sustainable production of hydrogen, but often trial-and-error approaches are used for their development. Now, principles are elucidated that suggest pathways to rationally design efficient metal-free electrocatalysts based on doped graphene.

  1. The Summer of Hydrogen

    NASA Technical Reports Server (NTRS)

    Weber, Philip

    2008-01-01

    Ground crew veterans at Kennedy Space Center still talk about what they call "the summer of hydrogen"-the long, frustrating months in 1990 when the shuttle fleet was grounded by an elusive hydrogen leak that foiled our efforts to fill the orbiter's external fuel tank. Columbia (STS-35) was on Launch Pad A for a scheduled May 30 launch when we discovered the hydrogen leak during - tanking. The external fuel tank is loaded through the orbiter. Liquid hydrogen flows through a 17-inch umbilical between the orbiter and the tank. During fueling, we purge the aft fuselage with gaseous nitrogen to reduce the risk of fire, and we have a leak-detection system in the mobile launch platform, which samples (via tygon tubing) the atmosphere in and around the vehicle, drawing it down to a mass spectrometer that analyzes its composition. When we progressed to the stage of tanking where liquid hydrogen flows through the vehicle, the concentration of hydrogen approached four percent-the limit above which it would be dangerously flammable. We had a leak. We did everything we could think of to find it, and the contractor who supplied the flight hardware was there every day, working alongside us. We did tanking tests, which involved instrumenting the suspected leak sources, and cryo-loaded the external tank to try to isolate precisely where the leak originated. We switched out umbilicals; we replaced the seals between the umbilical and the orbiter. We inspected the seals microscopically and found no flaws. We replaced the recirculation pumps, and we found and replaced a damaged teflon seal in a main propulsion system detent cover, which holds the prevalve-the main valve supplying hydrogen to Space Shuttle Main Engine 3 -in the open position. The seal passed leak tests at ambient temperature but leaked when cryogenic temperatures were applied. We added new leak sensors-up to twenty at a time and tried to be methodical in our placements to narrow down the possible sources of the problem

  2. Detroit Commuter Hydrogen Project

    SciTech Connect

    Brooks, Jerry; Prebo, Brendan

    2010-07-31

    This project was undertaken to demonstrate the viability of using hydrogen as a fuel in an internal combustion engine vehicle for use as a part of a mass transit system. The advantages of hydrogen as a fuel include renew-ability, minimal environmental impact on air quality and the environment, and potential to reduce dependence on foreign energy sources for the transportation sector. Recognizing the potential for the hydrogen fuel concept, the Southeast Michigan Congress of Governments (SEMCOG) determined to consider it in the study of a proposed regional mass transit rail system for southeast Michigan. SEMCOG wanted to evaluate the feasibility of using hydrogen fueled internal combustion engine (H2ICE) vehicles in shuttle buses to connect the Detroit Metro Airport to a proposed, nearby rail station. Shuttle buses are in current use on the airport for passenger parking and inter-terminal transport. This duty cycle is well suited to the application of hydrogen fuel at this time because of the ability to re-fuel vehicles at a single nearby facility, overcoming the challenge of restricted fuel availability in the undeveloped hydrogen fuel infrastructure. A cooperative agreement between SEMCOG and the DOE was initiated and two H2ICE buses were placed in regular passenger service on March 29, 2009 and operated for six months in regular passenger service. The buses were developed and built by the Ford Motor Company. Wayne County Airport Authority provided the location for the demonstration with the airport transportation contractor, Metro Cars Inc. operating the buses. The buses were built on Ford E450 chassis and incorporated a modified a 6.8L V-10 engine with specially designed supercharger, fuel rails and injectors among other sophisticated control systems. Up to 30 kg of on-board gaseous hydrogen were stored in a modular six tank, 350 bar (5000 psi) system to provide a 150 mile driving range. The bus chassis and body were configured to carry nine passengers with

  3. Hydrogen Storage Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The mission of the Hydrogen Storage Technical Team is to accelerate research and innovation that will lead to commercially viable hydrogen-storage technologies that meet the U.S. DRIVE Partnership goals.

  4. Oxidation resistant organic hydrogen getters

    DOEpatents

    Shepodd, Timothy J.; Buffleben, George M.

    2008-09-09

    A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably Pt. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently removing hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

  5. Onboard hydrogen generation for automobiles

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Cerini, D. J.

    1976-01-01

    Problems concerning the use of hydrogen as a fuel for motor vehicles are related to the storage of the hydrogen onboard a vehicle. The feasibility is investigated to use an approach based on onboard hydrogen generation as a means to avoid these storage difficulties. Two major chemical processes can be used to produce hydrogen from liquid hydrocarbons and methanol. In steam reforming, the fuel reacts with water on a catalytic surface to produce a mixture of hydrogen and carbon monoxide. In partial oxidation, the fuel reacts with air, either on a catalytic surface or in a flame front, to yield a mixture of hydrogen and carbon monoxide. There are many trade-offs in onboard hydrogen generation, both in the choice of fuels as well as in the choice of a chemical process. Attention is given to these alternatives, the results of some experimental work in this area, and the combustion of various hydrogen-rich gases in an internal combustion engine.

  6. Process for thermochemically producing hydrogen

    DOEpatents

    Bamberger, Carlos E.; Richardson, Donald M.

    1976-01-01

    Hydrogen is produced by the reaction of water with chromium sesquioxide and strontium oxide. The hydrogen producing reaction is combined with other reactions to produce a closed chemical cycle for the thermal decomposition of water.

  7. Accentuate the negative: the positive effects of negative acknowledgment.

    PubMed

    Ward, Andrew; Brenner, Lyle

    2006-11-01

    Three studies investigated the capacity of negative acknowledgment, the admission of an unfavorable quality, to elicit relatively positive responses. In Study 1, an acknowledgment that a written paragraph was confusing led individuals to rate the paragraph as clearer than they did when no acknowledgment was offered. In Study 2, a foreign speaker was rated as possessing a clearer voice when he acknowledged his strong accent than when he did not. In Study 3, a hypothetical college applicant's acknowledgment of receiving less than stellar high school grades resulted in a more positive evaluation of those grades. The interpersonal risks and benefits of negative acknowledgment as an impression-management strategy are discussed.

  8. Photovoltaic hydrogen production

    SciTech Connect

    Hiser, H.W.; Memory, S.B.; Veziroglu, T.N.; Padin, J.

    1996-10-01

    This is a new project, which started in June 1995, and involves photovoltaic hydrogen production as a fuel production method for the future. In order to increase the hydrogen yield, it was decided to use hybrid solar collectors to generate D.C. electricity, as well as high temperature steam for input to the electrolyzer. In this way, some of the energy needed to dissociate the water is supplied in the form of heat (or low grade energy), to generate steam, which results in a reduction of electrical energy (or high grade energy) needed. As a result, solar to hydrogen conversion efficiency is increased. In the above stated system, the collector location, the collector tracking sub-system (i.e., orientation/rotation), and the steam temperature have been taken as variables. Five locations selected - in order to consider a variety of latitudes, altitudes, cloud coverage and atmospheric conditions - are Atlanta, Denver, Miami, Phoenix and Salt Lake City. Plain PV and hybrid solar collectors for a stationary south facing system and five different collector rotation systems have been analyzed. Steam temperatures have been varied between 200{degrees}C and 1200{degrees}C. During the first year, solar to hydrogen conversion efficiencies have been considered. The results show that higher steam temperatures, 2 dimensional tracking system, higher elevations and dryer climates causes higher conversion efficiencies. Cost effectiveness of the sub-systems and of the overall system will be analyzed during the second year. Also, initial studies will be made of an advanced high efficiency hybrid solar hydrogen production system.

  9. Task D: Hydrogen safety analysis

    SciTech Connect

    Swain, M.R.; Sievert, B.G.; Swain, M.N.

    1996-10-01

    This report covers two topics. The first is a review of codes, standards, regulations, recommendations, certifications, and pamphlets which address safety of gaseous fuels. The second is an experimental investigation of hydrogen flame impingement. Four areas of concern in the conversion of natural gas safety publications to hydrogen safety publications are delineated. Two suggested design criteria for hydrogen vehicle fuel systems are proposed. It is concluded from the experimental work that light weight, low cost, firewalls to resist hydrogen flame impingement are feasible.

  10. Hydrogen Fire Spectroscopy Issues Project

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Compiler)

    2014-01-01

    The detection of hydrogen fires is important to the aerospace community. The National Aeronautics and Space Administration (NASA) has devoted significant effort to the development, testing, and installation of hydrogen fire detectors based on ultraviolet, near-infrared, mid-infrared, andor far-infrared flame emission bands. Yet, there is no intensity calibrated hydrogen-air flame spectrum over this range in the literature and consequently, it can be difficult to compare the merits of different radiation-based hydrogen fire detectors.

  11. Bis(benzyl­tri­methyl­ammonium) bis­[(4SR,12SR,18RS,26RS)-4,18,26-trihy­droxy-12-oxido-13,17-dioxahepta­cyclo­[14.10.0.03,14.04,12.06,11.018,26.019,24]hexa­cosa-1,3(14),6,8,10,15,19,21,23-nona­ene-5,25-dione] sesquihydrate: dimeric structure formation via [O—H—O]− negative charge-assisted hydrogen bonds (–CAHB) with benzyl­tri­methyl­ammonium counter-ions

    PubMed Central

    Bengiat, Ravell; Gil, Maayan; Klein, Asne; Bogoslavsky, Benny; Cohen, Shmuel; Almog, Joseph

    2016-01-01

    The reaction between bis-ninhydrin resorcinol and benzyl­tri­methyl­ammonium fluoride in ethanol has produced the title compound, 2C10H16N+·2C24H13O8 −·1.5H2O, which contains a unique centrosymmetric supra­molecular dimeric entity, where two deprotonated ligands are held together via two strong and short [O⋯O = 2.4395 (13) Å] [O—H—O]− bonds of the type negative charge-assisted hydrogen bonds (–CAHB). The central aromatic rings of the ligands create parallel-displaced π–π stacking at an inter­planar distance of 3.381 (1) Å, which helps stabilize the dimer. In the crystal, two symmetry-related solvent water mol­ecules with a site occupancy of 0.75 are attached to the carbonyl groups of the dimer by weaker O—H⋯O hydrogen bonds, forming chains along [101]. PMID:27006816

  12. Bis(benzyl-tri-methyl-ammonium) bis-[(4SR,12SR,18RS,26RS)-4,18,26-trihy-droxy-12-oxido-13,17-dioxahepta-cyclo-[14.10.0.0(3,14).0(4,12).0(6,11).0(18,26).0(19,24)]hexa-cosa-1,3(14),6,8,10,15,19,21,23-nona-ene-5,25-dione] sesquihydrate: dimeric structure formation via [O-H-O](-) negative charge-assisted hydrogen bonds (-CAHB) with benzyl-tri-methyl-ammonium counter-ions.

    PubMed

    Bengiat, Ravell; Gil, Maayan; Klein, Asne; Bogoslavsky, Benny; Cohen, Shmuel; Almog, Joseph

    2016-03-01

    The reaction between bis-ninhydrin resorcinol and benzyl-tri-methyl-ammonium fluoride in ethanol has produced the title compound, 2C10H16N(+)·2C24H13O8 (-)·1.5H2O, which contains a unique centrosymmetric supra-molecular dimeric entity, where two deprotonated ligands are held together via two strong and short [O⋯O = 2.4395 (13) Å] [O-H-O](-) bonds of the type negative charge-assisted hydrogen bonds (-CAHB). The central aromatic rings of the ligands create parallel-displaced π-π stacking at an inter-planar distance of 3.381 (1) Å, which helps stabilize the dimer. In the crystal, two symmetry-related solvent water mol-ecules with a site occupancy of 0.75 are attached to the carbonyl groups of the dimer by weaker O-H⋯O hydrogen bonds, forming chains along [101]. PMID:27006816

  13. EDITORIAL: Negative ion based neutral beam injection

    NASA Astrophysics Data System (ADS)

    Hemsworth, R. S.

    2006-06-01

    It is widely recognized that neutral beam injection (NBI), i.e. the injection of high energy, high power, beams of H or D atoms, is a flexible and reliable system that has been the main heating system on a large variety of fusion devices, and NBI has been chosen as one of the three heating schemes of the International Tokomak Reactor (ITER). To date, all the NBI systems but two have been based on the neutralization (in a simple gas target) of positive hydrogen or deuterium ions accelerated to <100 keV/nucleon. Above that energy the neutralization of positive ions falls to unacceptably low values, and higher energy neutral beams have to be created by the neutralization of accelerated negative ions (in a simple gas target), as this remains high (approx60%) up to >1 MeV/nucleon. Unfortunately H- and D- are difficult to create, and the very characteristic that makes them attractive, the ease with which the electron is detached from the ion, means that it is difficult to create high concentrations or fluxes of them, and it is difficult to avoid substantial, collisional, losses in the extraction and acceleration processes. However, there has been impressive progress in negative ion sources and accelerators over the past decade, as demonstrated by the two pioneering, operational, multi-megawatt, negative ion based, NBI systems at LHD (180 keV, H0) and JT-60U (500 keV, D0), both in Japan. Nevertheless, the system proposed for ITER represents a substantial technological challenge as an increase is required in beam energy, to 1 MeV, D0, accelerated ion (D-) current, to 40 A, accelerated current density, 200 A m-2 of D-, and pulse length, to 1 h. At the Fourth IAEA Technical Meeting on Negative Ion Based Neutral Beam Injectors, hosted by the Consorzio RFX, Padova, Italy, 9-11 May 2005, the status of the R&D aimed at the realization of the injectors for ITER was presented. Because of the importance of this development to the success of the ITER project, participants at that

  14. Graphene nanopores as negative differential resistance devices

    SciTech Connect

    Qiu, Wanzhi; Nguyen, Phuong Duc; Skafidas, Efstratios

    2015-02-07

    We present graphene nanopores as new negative differential resistance (NDR) devices, and study their quantum transport properties using non-equilibrium Green's function and the density functional tight binding method. The proposed device structure is created on intrinsic armchair-edged graphene nanoribbons with uniform widths, where the central scattering region has a nanopore in the interior, and the two ends of the nanoribbon act naturally as connecting electrodes. We show that nitrogen-passivated scattering regions generally result in pronounced NDR properties, while hydrogen-passivated ones do not. This NDR effect occurs at low bias voltages, below 1 V, and achieves extraordinarily high peak-to-valley current ratio, while still attaining very high peak current densities. In addition, very sharp current peaks in the μA range can occur in the I-V curves, and through varying structural dimensions of the proposed structure multiple NDR regions can be realized. These results suggest that the device has promising potential in applications such as high frequency oscillators, memory devices, and fast switches.

  15. Input calibration for negative originals

    NASA Astrophysics Data System (ADS)

    Tuijn, Chris

    1995-04-01

    One of the major challenges in the prepress environment consists of controlling the electronic color reproduction process such that a perfect match of any original can be realized. Whether this goal can be reached depends on many factors such as the dynamic range of the input device (scanner, camera), the color gamut of the output device (dye sublimation printer, ink-jet printer, offset), the color management software etc. The characterization of the color behavior of the peripheral devices is therefore very important. Photographs and positive transparents reflect the original scene pretty well; for negative originals, however, there is no obvious link to either the original scene or a particular print of the negative under consideration. In this paper, we establish a method to scan negatives and to convert the scanned data to a calibrated RGB space, which is known colorimetrically. This method is based on the reconstruction of the original exposure conditions (i.e., original scene) which generated the negative. Since the characteristics of negative film are quite diverse, a special calibration is required for each combination of scanner and film type.

  16. Hydrogen and sulfur recovery from hydrogen sulfide wastes

    DOEpatents

    Harkness, John B. L.; Gorski, Anthony J.; Daniels, Edward J.

    1993-01-01

    A process for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

  17. Hydrogen and sulfur recovery from hydrogen sulfide wastes

    DOEpatents

    Harkness, J.B.L.; Gorski, A.J.; Daniels, E.J.

    1993-05-18

    A process is described for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is [dis]associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

  18. Magnetic levitation of condensed hydrogen

    NASA Technical Reports Server (NTRS)

    Paine, C. G.; Seidel, G. M.

    1991-01-01

    Liquid and solid molecular hydrogen has been levitated using a pair of small superconducting solenoids. The hydrogen samples, up to 3 mm in dimension, were trapped in a magnetic potential having either a discrete minimum or a minimum in the form of a ring 1 cm in diameter. The hydrogen could be moved about in the magnetic trap by applying an electric field.

  19. Hydrogen, socio-environmental impact

    NASA Technical Reports Server (NTRS)

    Gilmore, J. S.; Matthews, W. E.; Duff, M. K.

    1975-01-01

    The concept and logic flow of a hydrogen technology assessment are described along with a specific procedure for such an assessment. The development of hydrogen technology is discussed. Factors considered in the development and use of hydrogen include: stimulus of societal needs and technological innovations; economic factors; and social and environmental effects.

  20. Hydrogen rotation-vibration oscillator

    DOEpatents

    Rhodes, C.K.

    1974-01-29

    A laser system is described wherein molecular species of hydrogen and hydrogen isotopes are induced to oscillate on rotational-vibrational levels by subjecting the hydrogen to a transverse beam of electrons of a narrowly defined energy between about 1 and 5 eV, thereby producing high intensity and high energy output. (Official Gazette)

  1. Nickel-hydrogen component development

    NASA Technical Reports Server (NTRS)

    Charleston, J. A.

    1983-01-01

    Light weight energy storage systems for future space missions are investigated. One of the systems being studied is the nickel hydrogen battery. This battery is designed to achieve longer life, improve performance, and higher energy densities for space applications. The nickel hydrogen component development is discussed. Test data from polarization measurements of the hydrogen electrode component is presented.

  2. Hydrogen as an energy vector

    NASA Technical Reports Server (NTRS)

    Powers, W. D.

    1975-01-01

    The feasibility of utilizing hydrogen as an energy vector is considered, with special attention given to means of hydrogen production. The state-of-the-art in thermochemical processes is reviewed, and criteria for the technical and economic feasibility of large-scale thermochemical water splitting processes are presented. The production of hydrogen from coal and from photolysis of water is discussed.

  3. Negative Transportation and Cross-Linguistic Negative Evidence.

    ERIC Educational Resources Information Center

    Soga, Matsuo

    1972-01-01

    This paper considers whether the negative transportation (NT) rule operating in English is operative also in Japanese and whether investigation of the phenomenon in Japanese may provide new insights for English research. The discussion begins with an explanation and examples of the NT rule in English. Japanese cases are then studied, and the…

  4. Fractional quantum conductance values in Au nanoelectrodes due to hydrogen adsorption

    NASA Astrophysics Data System (ADS)

    Díaz, M.; Martín-González, M. S.; Costa-Krämer, J. L.

    2010-08-01

    Hydrogen adsorption in gold nanocontact electrodes in electrochemical solution is experimentally discerned. This is performed with gold nanocontact conductance histograms in an electrochemical environment in which both the electrochemical potential and the electrolyte type are varied. Different salts, acids, and hydrogen peroxide electrolytes are studied. Salts and acids exhibit at negative electrochemical potentials different fractional quantum conductance histograms peaks associated to extra stable structures due to H adsorption while these peaks do not appear for H 2O 2 where electron transfer between solution and electrodes occurs without hydrogen formation or hydrogen adsorption on the gold electrode.

  5. Hydrogen attack - Influence of hydrogen sulfide. [on carbon steel

    NASA Technical Reports Server (NTRS)

    Eliezer, D.; Nelson, H. G.

    1978-01-01

    An experimental study is conducted on 12.5-mm-thick SAE 1020 steel (plain carbon steel) plate to assess hydrogen attack at room temperature after specimen exposure at 525 C to hydrogen and a blend of hydrogen sulfide and hydrogen at a pressure of 3.5 MN/sq m for exposure times up to 240 hr. The results are discussed in terms of tensile properties, fissure formation, and surface scales. It is shown that hydrogen attack from a high-purity hydrogen environment is severe, with the formation of numerous methane fissures and bubbles along with a significant reduction in the room-temperature tensile yield and ultimate strengths. However, no hydrogen attack is observed in the hydrogen/hydrogen sulfide blend environment, i.e. no fissure or bubble formation occurred and the room-temperature tensile properties remained unchanged. It is suggested that the observed porous discontinuous scale of FeS acts as a barrier to hydrogen entry, thus reducing its effective equilibrium solubility in the iron lattice. Therefore, hydrogen attack should not occur in pressure-vessel steels used in many coal gasification processes.

  6. Negative Electron Affinity Effect on the Surface of Chemical Vapor Deposited Diamond Polycrystalline Films

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.; Mearini, G. T.; Dayton, J. A., Jr.

    1996-01-01

    Strong negative electron affinity effects have been observed on the surface of as-grown chemical vapor deposited diamond using Secondary Electron Emission. The test samples were randomly oriented and the surface was terminated with hydrogen. The effect appears as an intensive peak in the low energy part of the spectrum of the electron energy distribution and may be described in the model of effective negative electron affinity.

  7. Patch Test Negative Generalized Dermatitis.

    PubMed

    Spiker, Alison; Mowad, Christen

    2016-01-01

    Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.

  8. Sigma models with negative curvature

    NASA Astrophysics Data System (ADS)

    Alonso, Rodrigo; Jenkins, Elizabeth E.; Manohar, Aneesh V.

    2016-05-01

    We construct Higgs Effective Field Theory (HEFT) based on the scalar manifold Hn, which is a hyperbolic space of constant negative curvature. The Lagrangian has a non-compact O (n , 1) global symmetry group, but it gives a unitary theory as long as only a compact subgroup of the global symmetry is gauged. Whether the HEFT manifold has positive or negative curvature can be tested by measuring the S-parameter, and the cross sections for longitudinal gauge boson and Higgs boson scattering, since the curvature (including its sign) determines deviations from Standard Model values.

  9. Hydrogen diffusion in Zircon

    NASA Astrophysics Data System (ADS)

    Ingrin, Jannick; Zhang, Peipei

    2016-04-01

    Hydrogen mobility in gem quality zircon single crystals from Madagascar was investigated through H-D exchange experiments. Thin slices were annealed in a horizontal furnace flushed with a gas mixture of Ar/D2(10%) under ambient pressure between 900 ° C to 1150 ° C. FTIR analyses were performed on oriented slices before and after each annealing run. H diffusion along [100] and [010] follow the same diffusion law D = D0exp[-E /RT], with log D0 = 2.24 ± 1.57 (in m2/s) and E = 374 ± 39 kJ/mol. H diffusion along [001] follows a slightly more rapid diffusion law, with log D0 = 1.11 ± 0.22 (in m2/s) and E = 334 ± 49 kJ/mol. H diffusion in zircon has much higher activation energy and slower diffusivity than other NAMs below 1150 ° C even iron-poor garnets which are known to be among the slowest (Blanchard and Ingrin, 2004; Kurka et al. 2005). During H-D exchange zircon incorporates also deuterium. This hydration reaction involves uranium reduction as it is shown from the exchange of U5+ and U4+ characteristic bands in the near infrared region during annealing. It is the first time that a hydration reaction U5+ + OH‑ = U4+ + O2‑ + 1/2H2, is experimentally reported. The kinetics of deuterium incorporation is slightly slower than hydrogen diffusion, suggesting that the reaction is limited by hydrogen mobility. Hydrogen isotopic memory of zircon is higher than other NAMs. Zircons will be moderately retentive of H signatures at mid-crustal metamorphic temperatures. At 500 ° C, a zircon with a radius of 300 μm would retain its H isotopic signature over more than a million years. However, a zircon is unable to retain this information for geologically significant times under high-grade metamorphism unless the grain size is large enough. Refrences Blanchard, M. and Ingrin, J. (2004) Hydrogen diffusion in Dora Maira pyrope. Physics and Chemistry of Minerals, 31, 593-605. Kurka, A., Blanchard, M. and Ingrin, J. (2005) Kinetics of hydrogen extraction and deuteration in

  10. Hydrogen Diffusion in Forsterite

    NASA Astrophysics Data System (ADS)

    Demouchy, S.; Mackwell, S.

    2002-12-01

    Physical and chemical properties of Earth's mantle are readily modified by interaction with volatiles, such as water. Thus, characterization of solubility and kinetics of incorporation for water in nominally anhydrous minerals is important in order to understand the behavior of Earth's interior under hydrous conditions. Experimental studies on the olivine-water system indicate that significant amounts of OH can dissolve within olivine as point defects (Bell and Rossman, 1992; Kohlstedt et al. 1996). Extending Kohlstedt and Mackwell's (1998) work, our study concerns the kinetics of hydrogen transport in the iron-free olivine-water system. This study is based on hydrogenation of forsterite samples during piston-cylinder and TZM cold-seal vessel experiments. We use infrared analyses in order to constrain the speciation of the mobile water-derived defects in forsterite single-crystal sample, and the rates of diffusion of such species under uppermost mantle conditions (0.2 to 1.5 GPa, 900 to 1100° C). Hydrogen defect transport in single crystals of forsterite is investigated for diffusion parallel to each crystallographic axis. Defect diffusivities are obtained by fitting a diffusion law to the OH content as a function of position in the sample. Our current results indicate that incorporation of hydroxyl species into iron-free olivine is a one-stage process with hydrogen diffusion linked to magnesium vacancy self-diffusion DV, such that DV = D~/3 = 10-12 m2/s at 1000° C parallel to [001], where D~ represents the chemical diffusivity. Those diffusion rates are slightly lower than in iron-bearing olivine for the same incorporation mechanism. The different concentration profiles show a clear anisotropy of diffusion, with fastest diffusion parallel to [001] as in iron-bearing olivine. Thus, while hydrogen solubilities are dependent on iron content, the rate of incorporation of water-derived species in olivine is not strongly coupled to the concentration of iron. This

  11. Hydrogen diffusion in Zircon

    NASA Astrophysics Data System (ADS)

    Ingrin, Jannick; Zhang, Peipei

    2016-04-01

    Hydrogen mobility in gem quality zircon single crystals from Madagascar was investigated through H-D exchange experiments. Thin slices were annealed in a horizontal furnace flushed with a gas mixture of Ar/D2(10%) under ambient pressure between 900 ° C to 1150 ° C. FTIR analyses were performed on oriented slices before and after each annealing run. H diffusion along [100] and [010] follow the same diffusion law D = D0exp[-E /RT], with log D0 = 2.24 ± 1.57 (in m2/s) and E = 374 ± 39 kJ/mol. H diffusion along [001] follows a slightly more rapid diffusion law, with log D0 = 1.11 ± 0.22 (in m2/s) and E = 334 ± 49 kJ/mol. H diffusion in zircon has much higher activation energy and slower diffusivity than other NAMs below 1150 ° C even iron-poor garnets which are known to be among the slowest (Blanchard and Ingrin, 2004; Kurka et al. 2005). During H-D exchange zircon incorporates also deuterium. This hydration reaction involves uranium reduction as it is shown from the exchange of U5+ and U4+ characteristic bands in the near infrared region during annealing. It is the first time that a hydration reaction U5+ + OH- = U4+ + O2- + 1/2H2, is experimentally reported. The kinetics of deuterium incorporation is slightly slower than hydrogen diffusion, suggesting that the reaction is limited by hydrogen mobility. Hydrogen isotopic memory of zircon is higher than other NAMs. Zircons will be moderately retentive of H signatures at mid-crustal metamorphic temperatures. At 500 ° C, a zircon with a radius of 300 μm would retain its H isotopic signature over more than a million years. However, a zircon is unable to retain this information for geologically significant times under high-grade metamorphism unless the grain size is large enough. Refrences Blanchard, M. and Ingrin, J. (2004) Hydrogen diffusion in Dora Maira pyrope. Physics and Chemistry of Minerals, 31, 593-605. Kurka, A., Blanchard, M. and Ingrin, J. (2005) Kinetics of hydrogen extraction and deuteration in

  12. Wind-To-Hydrogen Energy Pilot Project

    SciTech Connect

    Ron Rebenitsch; Randall Bush; Allen Boushee; Brad G. Stevens; Kirk D. Williams; Jeremy Woeste; Ronda Peters; Keith Bennett

    2009-04-24

    study showed that several factors can greatly affect, both positively and negatively, the "per kg" cost of hydrogen. After a September 15, 2005, meeting to evaluate the advisability of funding Phase II of the project DOE concurred with BEPC that Phase I results did warrant a "go" recommendation to proceed with Phase II activities. The hydrogen production system was built by Hydrogenics and consisted of several main components: hydrogen production system, gas control panel, hydrogen storage assembly and hydrogen-fueling dispenser The hydrogen production system utilizes a bipolar alkaline electrolyzer nominally capable of producing 30 Nm3/h (2.7 kg/h). The hydrogen is compressed to 6000 psi and delivered to an on-site three-bank cascading storage assembly with 80 kg of storage capacity. Vehicle fueling is made possible through a Hydrogenics-provided gas control panel and dispenser able to fuel vehicles to 5000 psi. A key component of this project was the development of a dynamic scheduling system to control the wind energy's variable output to the electrolyzer cell stacks. The dynamic scheduling system received an output signal from the wind farm, processed this signal based on the operational mode, and dispatched the appropriate signal to the electrolyzer cell stacks. For the study BEPC chose to utilize output from the Wilton wind farm located in central ND. Site design was performed from May 2006 through August 2006. Site construction activities were from August to November 2006 which involved earthwork, infrastructure installation, and concrete slab construction. From April - October 2007, the system components were installed and connected. Beginning in November 2007, the system was operated in a start-up/shakedown mode. Because of numerous issues, the start-up/shakedown period essentially lasted until the end of January 2008, at which time a site acceptance test was performed. Official system operation began on February 14, 2008, and continued through the end of

  13. High-Yield Hydrogen Production from Starch and Water by a Synthetic Enzymatic Pathway

    PubMed Central

    Zhang, Y.-H. Percival; Evans, Barbara R.; Mielenz, Jonathan R.; Hopkins, Robert C.; Adams, Michael W.W.

    2007-01-01

    Background The future hydrogen economy offers a compelling energy vision, but there are four main obstacles: hydrogen production, storage, and distribution, as well as fuel cells. Hydrogen production from inexpensive abundant renewable biomass can produce cheaper hydrogen, decrease reliance on fossil fuels, and achieve zero net greenhouse gas emissions, but current chemical and biological means suffer from low hydrogen yields and/or severe reaction conditions. Methodology/Principal Findings Here we demonstrate a synthetic enzymatic pathway consisting of 13 enzymes for producing hydrogen from starch and water. The stoichiometric reaction is C6H10O5 (l)+7 H2O (l)→12 H2 (g)+6 CO2 (g). The overall process is spontaneous and unidirectional because of a negative Gibbs free energy and separation of the gaseous products with the aqueous reactants. Conclusions Enzymatic hydrogen production from starch and water mediated by 13 enzymes occurred at 30°C as expected, and the hydrogen yields were much higher than the theoretical limit (4 H2/glucose) of anaerobic fermentations. Significance The unique features, such as mild reaction conditions (30°C and atmospheric pressure), high hydrogen yields, likely low production costs ($∼2/kg H2), and a high energy-density carrier starch (14.8 H2-based mass%), provide great potential for mobile applications. With technology improvements and integration with fuel cells, this technology also solves the challenges associated with hydrogen storage, distribution, and infrastructure in the hydrogen economy. PMID:17520015

  14. Calibrating the DARHT Electron Spectrometer with Negative Ions

    SciTech Connect

    R. Trainham , A. P. Tipton , and R. R. Bartech

    2005-11-01

    Negative ions of hydrogen and oxygen have been used to calibrate the DARHT electron spectrometer over the momentum range of 2 to 20 MeV/c. The calibration was performed on September 1, 3, and 8, 2004, and it is good to 0.5% absolute, provided that instrument alignment is carefully controlled. The momentum in MeV/c as a function of magnetic field (B in Gauss) and position in the detector plane (X in mm) is: P = (B-6.28)/(108.404-0.1935*X)

  15. Solid evacuated microspheres of hydrogen

    DOEpatents

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1982-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  16. PHOTOBIOLOGICAL HYDROGEN RESEARCH

    SciTech Connect

    Philippidis, George; Tek, Vekalet

    2009-07-01

    The project objectives are to develop bio-hydrogen production by: Cloning the structural and subunit genes (cooKMUX and cooLH resp.) of the O{sub 2}- tolerant NiFe-hydrogenase from the photosynthetic bacterium Rubrivivax gelatinosus CBS strain in collaboration with NREL. Cloning the active site maturation genes (hypA-F) of the CBS hydrogenase in collaboration with NREL. Transforming the structural and subunits genes, along with the maturation genes, into E. coli and determining the minimum number of genes required for expression of a functional hydrogenase. Upon expression of a functional hydrogenase, purifying and characterizing the recombinant hydrogenase from E. coli and performing bioreactor studies to optimize hydrogen production by E. coli.

  17. Geothermal hydrogen sulfide removal

    SciTech Connect

    Urban, P.

    1981-04-01

    UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

  18. Container for hydrogen isotopes

    DOEpatents

    Solomon, David E.

    1977-01-01

    A container for the storage, shipping and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same which has compactness, which is safe against fracture or accident, and which is reusable. The container consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example, of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and will be retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates.

  19. Thermochemical production of hydrogen

    DOEpatents

    Dreyfuss, Robert M.

    1976-07-13

    A thermochemical reaction cycle for the generation of hydrogen from water comprising the following sequence of reactions wherein M represents a metal and Z represents a metalloid selected from the arsenic-antimony-bismuth and selenium-tellurium subgroups of the periodic system: 2MO + Z + SO.sub.2 .fwdarw. MZ + MSO.sub.4 (1) mz + h.sub.2 so.sub.4 .fwdarw. mso.sub.4 + h.sub.2 z (2) 2mso.sub.4 .fwdarw. 2mo + so.sub.2 + so.sub.3 + 1/20.sub.2 (3) h.sub.2 z .fwdarw. z + h.sub.2 (4) h.sub.2 o + so.sub.3 .fwdarw. h.sub.2 so.sub.4 (5) the net reaction is the decomposition of water into hydrogen and oxygen.

  20. Hydrogen Reclamation and Reutilization

    NASA Technical Reports Server (NTRS)

    Hebert, Bartt; Lansaw, John

    2009-01-01

    John C. Stennis Space Center (SSC) provides rocket engine propulsion testing for NASA's space programs. Since the development of the Space Shuttle, every Space Shuttle Main Engine (SSME) has undergone acceptance testing at SSC before going to Kennedy Space Center (KSC) for integration into the Space Shuttle. The SSME is a large cryogenic rocket engine that uses Liquid Hydrogen (LH2) as the fuel. As NASA moves to the new ARES V launch system, the main engines on the new vehicle, as well as the upper stage engine, are currently base lined to be cryogenic rocket engines that will also use LH2. The main rocket engines for the ARES V will be larger than the SSME, while the upper stage engine will be approximately half that size. As a result, significant quantities of hydrogen will be required during the development, testing, and operation of these rocket engines.

  1. Reversible hydrogen storage materials

    DOEpatents

    Ritter, James A.; Wang, Tao; Ebner, Armin D.; Holland, Charles E.

    2012-04-10

    In accordance with the present disclosure, a process for synthesis of a complex hydride material for hydrogen storage is provided. The process includes mixing a borohydride with at least one additive agent and at least one catalyst and heating the mixture at a temperature of less than about 600.degree. C. and a pressure of H.sub.2 gas to form a complex hydride material. The complex hydride material comprises MAl.sub.xB.sub.yH.sub.z, wherein M is an alkali metal or group IIA metal, Al is the element aluminum, x is any number from 0 to 1, B is the element boron, y is a number from 0 to 13, and z is a number from 4 to 57 with the additive agent and catalyst still being present. The complex hydride material is capable of cyclic dehydrogenation and rehydrogenation and has a hydrogen capacity of at least about 4 weight percent.

  2. Parity nonconservation in hydrogen.

    SciTech Connect

    Dunford, R. W.; Holt, R. J.

    2011-01-01

    We discuss the prospects for parity violation experiments in atomic hydrogen and deuterium to contribute to testing the Standard Model (SM). We find that, if parity experiments in hydrogen can be done, they remain highly desirable because there is negligible atomic-physics uncertainty and low energy tests of weak neutral current interactions are needed to probe for new physics beyond the SM. Analysis of a generic APV experiment in deuterium indicates that a 0.3% measurement of C{sub 1D} requires development of a slow (77K) metastable beam of {approx} 5 x 10{sup 14}D(2S)s{sup -1} per hyperfine component. The advent of UV radiation from free electron laser (FEL) technology could allow production of such a beam.

  3. Spontaneous combustion of hydrogen

    NASA Technical Reports Server (NTRS)

    Nusselt, Wilhelm; Pothmann, PH

    1923-01-01

    It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.

  4. Hydrogen-antihydrogen collisions

    PubMed

    Froelich; Jonsell; Saenz; Zygelman; Dalgarno

    2000-05-15

    Matter-antimatter interactions are investigated using hydrogen-antihydrogen collisions as an example. Cross sections for elastic scattering and for the antihydrogen loss (either through the rearrangement reaction, resulting in formation of protonium and positronium according to H+&Hmacr;-->p&pmacr;+e(+)e(-), or via annihilation in flight) are calculated for the first time in a fully quantum mechanical approach. Implications for experiments intending to trap and cool antihydrogen are discussed.

  5. Coal liquefaction and hydrogenation

    DOEpatents

    Schindler, Harvey D.

    1985-01-01

    The coal liquefaction process disclosed uses three stages. The first stage is a liquefaction. The second and third stages are hydrogenation stages at different temperatures and in parallel or in series. One stage is within 650.degree.-795.degree. F. and optimizes solvent production. The other stage is within 800.degree.-840.degree. F. and optimizes the C.sub.5 -850.degree. F. product.

  6. Hydrogen Exchange Mass Spectrometry.

    PubMed

    Mayne, Leland

    2016-01-01

    Hydrogen exchange (HX) methods can reveal much about the structure, energetics, and dynamics of proteins. The addition of mass spectrometry (MS) to an earlier fragmentation-separation HX analysis now extends HX studies to larger proteins at high structural resolution and can provide information not available before. This chapter discusses experimental aspects of HX labeling, especially with respect to the use of MS and the analysis of MS data.

  7. Polymer system for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    2000-01-01

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  8. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    1998-11-17

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  9. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, T.J.; Whinnery, L.L.

    1998-11-17

    A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen. 1 fig.

  10. Polymer system for gettering hydrogen

    SciTech Connect

    2000-05-16

    A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  11. Advanced hydrogen utilization technology demonstration

    SciTech Connect

    Hedrick, J C; Winsor, R E

    1994-06-01

    This report presents the results of a study done by Detroit Diesel Corporation (DDC). DDC used a 6V-92TA engine for experiments with hydrogen fuel. The engine was first baseline tested using methanol fuel and methanol unit injectors. One cylinder of the engine was converted to operate on hydrogen fuel, and methanol fueled the remaining five cylinders. This early testing with only one hydrogen-fueled cylinder was conducted to determine the operating parameters that would later be implemented for multicylinder hydrogen operation. Researchers then operated three cylinders of the engine on hydrogen fuel to verify single-cylinder idle tests. Once it was determined that the engine would operate well at idle, the engine was modified to operate with all six cylinders fueled with hydrogen. Six-cylinder operation on hydrogen provided an opportunity to verify previous test results and to more accurately determine the performance, thermal efficiency, and emissions of the engine.

  12. Curvature, Hydrogen, Q

    SciTech Connect

    Wallace, John Paul; Myneni, Ganapati Rao; Pike, Robert

    2011-03-31

    The manufacturing of niobium SRF accelerator cavities is plagued by a mobile point defect, hydrogen. For efficient accelerator operation, niobium must function at both high electric and magnetic fields, and is compromised if magnetic impurities are located in the surface regions of the material. The finding that trace hydrogen in niobium can produce structures with magnetic properties is a feature that is not acceptable for a high performance cavity. X-ray diffraction has proved to be the key tool in assessing irreversible process damage to the niobium substrate. In future generations of accelerators, niobium will actually be merely the substrate for more effective superconductors that will allow for more efficient operation. The substrate analogy to the silicon wafer industry is useful since for niobium it may be possible to avoid some of the mistakes made in silicon technology. Because hydrogen attacks niobium on a number of different size scales, there is an inherent complexity in the trouble sources. There are also features in cavity design that are benign, such as local curvature considerations, requiring a fully non symmetric analysis of current flow to be appreciated.

  13. Curvature, Hydrogen, Q

    SciTech Connect

    John Paul Wallace, Ganapati Rao Myneni, and Robert Pike

    2011-03-01

    The manufacturing of niobium SRF accelerator cavities is plagued by a mobile point defect, hydrogen. For efficient accelerator operation, niobium must function at both high electric and magnetic fields, and is compromised if magnetic impurities are located in the surface regions of the material. The finding that trace hydrogen in niobium can produce structures with magnetic properties is a feature that is not acceptable for a high performance cavity. X-ray diffraction has proved to be the key tool in assessing irreversible process damage to the niobium substrate. In future generations of accelerators, niobium will actually be merely the substrate for more effective superconductors that will allow for more efficient operation. The substrate analogy to the silicon wafer industry is useful since for niobium it may be possible to avoid some of the mistakes made in silicon technology. Because hydrogen attacks niobium on a number of different size scales, there is an inherent complexity in the trouble sources. There are also features in cavity design that are benign, such as local curvature considerations, requiring a fully non symmetric analysis of current flow to be appreciated.

  14. Imino Transfer Hydrogenation Reductions.

    PubMed

    Wills, Martin

    2016-04-01

    This review contains a summary of recent developments in the transfer hydrogenation of C=N bonds, with a particularly focus on reports from within the last 10 years and asymmetric transformations. However, earlier work in the area is also discussed in order to provide context for the more recent results described. I focus strongly on the Ru/TsDPEN class of asymmetric transfer hydrogenation reactions originally reported by Noyori et al., together with examples of their applications, particularly to medically valuable target molecules. The recent developments in the area of highly active imine-reduction catalysts, notably those based on iridium, are also described in some detail. I discuss diastereoselective reduction methods as a route to the synthesis of chiral amines using transfer hydrogenation. The recent development of a methodology for positioning reduction complexes within chiral proteins, permitting the generation of asymmetric reduction products through a directed modification of the protein environment in a controlled manner, is also discussed. PMID:27573139

  15. Photoelectrochemical hydrogen production

    SciTech Connect

    Rocheleau, R.E.; Miller, E.; Zhang, Z.

    1995-09-01

    The large-scale production of hydrogen utilizing energy provided by a renewable source to split water is one of the most ambitious long-term goals of the U.S. Department of Energy`s Hydrogen Program. Photoelectrochemical devices-direct photoconversion systems utilizing a photovoltaic-type structure coated with water-splitting catalysts-represent a promising option to meet this goal. Direct solar-to-chemical conversion efficiencies greater than 7% and photoelectrode lifetimes of up to 30 hours in 1 molar KOH have been demonstrated in our laboratory using low-cost, amorphous-silicon-based photoelectrodes. Loss analysis models indicate that the DOE`s goal of 10% solar-to-chemical conversion can be met with amorphous-silicon-based structures optimized for hydrogen production. In this report, we describe recent progress in the development of thin-film catalytic/protective coatings, improvements in photoelectrode efficiency and stability, and designs for higher efficiency and greater stability.

  16. MSW to hydrogen

    SciTech Connect

    Pasternak, A.D.; Richardson, J.H.; Rogers, R.S.; Thorsness, C.B.; Wallman, H.; Richter, G.N.; Wolfenbarger, J.K.

    1994-04-19

    LLNL and Texaco are cooperatively developing a physical and chemical treatment method for the preparation and conversion of municipal solid waste (MSW) to hydrogen by gasification and purification. The laboratory focus will be on pretreatment of MSW waste in order to prepare a slurry of suitable viscosity and heating value to allow efficient and economical gasification and hydrogen production. Initial pretreatment approaches include (1) hydrothermal processing at saturated conditions around 300 C with or without chemical/pH modification and (2) mild dry pyrolysis with subsequent incorporation into an appropriate slurry. Initial experiments will be performed with newspaper, a major constituent of MSW, prior to actual work with progressively more representative MSW samples. Overall system modeling with special attention to energy efficiency and waste water handling of the pretreatment process will provide overall guidance to critical scale-up parameters. Incorporation of additional feed stock elements (e.g., heavy oil) will be evaluated subject to the heating value, viscosity, and economics of the MSW optimal slurry for hydrogen production. Ultimate scale-up of the optimized process will provide sufficient material for demonstration in the Texaco pilot facility; additional long term objectives include more detailed economic analysis of the process as a function of technical parameters and development of a measure/control system to ensure slagging ash for variable MSW feed stocks. Details of the overall project plan and initial experimental and modeling results are presented.

  17. Unimode metamaterials exhibiting negative linear compressibility and negative thermal expansion

    NASA Astrophysics Data System (ADS)

    Dudek, Krzysztof K.; Attard, Daphne; Caruana-Gauci, Roberto; Wojciechowski, Krzysztof W.; Grima, Joseph N.

    2016-02-01

    Unimode metamaterials made from rotating rigid triangles are analysed mathematically for their mechanical and thermal expansion properties. It is shown that these unimode systems exhibit positive Poisson’s ratios irrespective of size, shape and angle of aperture, with the Poisson’s ratio exhibiting giant values for certain conformations. When the Poisson’s ratio in one loading direction is larger than +1, the systems were found to exhibit the anomalous property of negative linear compressibility along this direction, that is, the systems expand in this direction when hydrostatically compressed. Also discussed are the thermal expansion properties of these systems under the assumption that the units exhibit increased rotational agitation once subjected to an increase in temperature. The effect of the geometric parameters on the aforementioned thermo-mechanical properties of the system, are discussed, with the aim of identifying negative behaviour.

  18. Muon transfer from hot muonic hydrogen atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R.; Bailey, J.M.; Beer, G.A.; Knowles, P.E.; Mason, G.R.; Olin, A.; Beveridge, J.L.; Marshall, G.M.; Brewer, J.H.; Forster, B.M.; Huber, T.M.; Kammel, P.; Zmeskal, J.; Kunselman, A.R.; Petitjean, C.

    1992-12-31

    A negative muon beam has been directed on adjacent solid layers of hydrogen and neon. Three targets differing by their deuterium concentration were investigated. Muonic hydrogen atoms can drift to the neon layer where the muon is immediately transferred. The time structure of the muonic neon X-rays follows the exponential law with a disappearance rate corresponding to the one of {mu}{sup {minus}p} atoms in each target. The rates {lambda}{sub pp{mu}} and {lambda}{sub pd} can be extracted.

  19. Volume production of negative ions in the reflex type ion source

    SciTech Connect

    Jimbo, K.

    1982-01-01

    The production of negative hydrogen ions is investigated in the reflex-type negative ion source. The extracted negative hydrogen currents of 9.7 mA (100 mA/cm/sup 2/) for H/sup -/ and of 4.1 mA (42 mA/cm/sup 2/) for D/sup -/ are obtained continuously. The impurity is less then 1%. An isotope effect of negative ion production is observed. When anomalous diffusion in the positive column was found by Lehnert and Hoh (1960), it was pointed out that the large particle loss produced by anomalous diffusion is compensated by the large particle production inside the plasma, i.e., the plasma tries to maintain itself. The self-sustaining property of the plasma is applied to the reflex-type negative ion source. Anomalous diffusion was artificially encouraged by changing the radial electric field inside the reflex discharge. The apparent encouragement of negative ion diffusion by the increase of density fluctuation amplitude is observed. Twice as much negative ion current was obtained with the artificial encouragement as without. It is found from the quasilinear theory that the inwardly directed radial electric field destabilizes the plasma in the reflex-type ion source. The nonlinear theory based on Yoshikawa method (1962) is extended, and the anomalous diffusion coefficient in a weakly ionized plasma is obtained. The electrostatic sheath trap, which increases the confinement of negative ions in the reflex-type ion source, is also discussed.

  20. H3O(+) tetrahedron induction in large negative linear compressibility.

    PubMed

    Wang, Hui; Feng, Min; Wang, Yu-Fang; Gu, Zhi-Yuan

    2016-05-17

    Despite the rarity, large negative linear compressibility (NLC) was observed in metal-organic framework material Zn(HO3PC4H8PO3H)∙2H2O (ZAG-4) in experiment. We find a unique NLC mechanism in ZAG-4 based on first-principle calculations. The key component to realize its large NLC is the deformation of H3O(+) tetrahedron. With pressure increase, the oxygen apex approaches and then is inserted into the tetrahedron base (hydrogen triangle). The tetrahedron base subsequently expands, which results in the b axis expansion. After that, the oxygen apex penetrates the tetrahedron base and the b axis contracts. The negative and positive linear compressibility is well reproduced by the hexagonal model and ZAG-4 is the first MOFs evolving from non re-entrant to re-entrant hexagon framework with pressure increase. This gives a new approach to explore and design NLC materials.

  1. H3O+ tetrahedron induction in large negative linear compressibility

    PubMed Central

    Wang, Hui; Feng, Min; Wang, Yu-Fang; Gu, Zhi-Yuan

    2016-01-01

    Despite the rarity, large negative linear compressibility (NLC) was observed in metal-organic framework material Zn(HO3PC4H8PO3H)∙2H2O (ZAG-4) in experiment. We find a unique NLC mechanism in ZAG-4 based on first-principle calculations. The key component to realize its large NLC is the deformation of H3O+ tetrahedron. With pressure increase, the oxygen apex approaches and then is inserted into the tetrahedron base (hydrogen triangle). The tetrahedron base subsequently expands, which results in the b axis expansion. After that, the oxygen apex penetrates the tetrahedron base and the b axis contracts. The negative and positive linear compressibility is well reproduced by the hexagonal model and ZAG-4 is the first MOFs evolving from non re-entrant to re-entrant hexagon framework with pressure increase. This gives a new approach to explore and design NLC materials. PMID:27184726

  2. Metalinguistic Negation in English and Arabic

    ERIC Educational Resources Information Center

    Nedwick, Kelly M.

    2014-01-01

    Negation is a unique and fascinating property of human language which has been given extensive theoretical and typological treatment. One categorization divides negation use into metalinguistic negation and descriptive negation (Horn, 1985). Descriptive negation (DN) is the truth-functional semantic operator which has received the most attention…

  3. Charged fullerenes as high-capacity hydrogen storage media.

    PubMed

    Yoon, Mina; Yang, Shenyuan; Wang, Enge; Zhang, Zhenyu

    2007-09-01

    Using first-principles calculations within density functional theory, we explore systematically the capacity of charged carbon fullerenes Cn (20 hydrogen storage media. We find that the binding strength of molecular hydrogen on either positively or negatively charged fullerenes can be dramatically enhanced to 0.18-0.32 eV, a desirable range for potential room-temperature, near ambient applications. The enhanced binding is delocalized in nature, surrounding the whole surface of a charged fullerene, and is attributed to the polarization of the hydrogen molecules by the high electric field generated near the surface of the charged fullerene. At full hydrogen coverage, these charged fullerenes can gain storage capacities of up to approximately 8.0 wt %. We also find that, contrary to intuitive expectation, fullerenes containing encapsulated metal atoms only exhibit negligible enhancement in the hydrogen binding strength, because the charge donated by the metal atoms is primarily confined inside the fullerene cages. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage media.

  4. Nickel-hydrogen battery with oxygen and electrolyte management features

    DOEpatents

    Sindorf, John F.

    1991-10-22

    A nickel-hydrogen battery or cell having one or more pressure vessels containing hydrogen gas and a plurality of cell-modules therein. Each cell-module includes a configuration of cooperatively associated oxygen and electrolyte mangement and component alignment features. A cell-module having electrolyte includes a negative electrode, a positive electrode adapted to facilitate oxygen diffusion, a separator disposed between the positive and negative electrodes for separating them and holding electrolyte for ionic conductivity, an absorber engaging the surface of the positive electrode facing away from the separator for providing electrolyte to the positive electrode, and a pair of surface-channeled diffusion screens for enclosing the positive and negative electrodes, absorber, and separator and for maintaining proper alignment of these components. The screens, formed in the shape of a pocket by intermittently sealing the edges together along as many as three sides, permit hydrogen gas to diffuse therethrough to the negative electrodes, and prevent the edges of the separator from swelling. Electrolyte is contained in the cell-module, absorbhed by the electrodes, the separator and the absorber.

  5. Hydrogen Fuel Pilot Plant and Hydrogen ICE Vehicle Testing

    SciTech Connect

    J. Francfort

    2005-03-01

    The U.S. Department Energy's Advanced Vehicle Testing Activity (AVTA) teamed with Electric Transportation Applications (ETA) and Arizona Public Service (APS) to develop the APS Alternative Fuel (Hydrogen) Pilot Plant that produces and compresses hydrogen on site through an electrolysis process by operating a PEM fuel cell in reverse; natural gas is also compressed onsite. The Pilot Plant dispenses 100% hydrogen, 15 to 50% blends of hydrogen and compressed natural gas (H/CNG), and 100% CNG via a credit card billing system at pressures up to 5,000 psi. Thirty internal combustion engine (ICE) vehicles (including Daimler Chrysler, Ford and General Motors vehicles) are operating on 100% hydrogen and 15 to 50% H/CNG blends. Since the Pilot Plant started operating in June 2002, they hydrogen and H/CNG ICE vehicels have accumulated 250,000 test miles.

  6. Photoinduced hydrogen-bonding dynamics.

    PubMed

    Chu, Tian-Shu; Xu, Jinmei

    2016-09-01

    Hydrogen bonding dynamics has received extensive research attention in recent years due to the significant advances in femtolaser spectroscopy experiments and quantum chemistry calculations. Usually, photoexcitation would cause changes in the hydrogen bonding formed through the interaction between hydrogen donor and acceptor molecules on their ground electronic states, and such transient strengthening or weakening of hydrogen bonding could be crucial for the photophysical transformations and the subsequent photochemical reactions that occurred on a time scale from tens of femtosecond to a few nanoseconds. In this article, we review the combined experimental and theoretical studies focusing on the ultrafast electronic and vibrational hydrogen bonding dynamics. Through these studies, new mechanisms and proposals and common rules have been put forward to advance our understanding of the hydrogen bondings dynamics in a variety of important photoinduced phenomena like photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer processes, chemosensor fluorescence sensing, rearrangements of the hydrogen-bond network including forming and breaking hydrogen bond in water. Graphical Abstract We review the recent advances on exploring the photoinduced hydrogen bonding dynamics in solutions through a joint approach of laser spectroscopy and theoretical calculation. The reviewed studies have put forward a new mechanism, new proposal, and new rule for a variety of photoinduced phenomena such as photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer, chemosensor fluorescence sensing, and rearrangements of the hydrogen-bond network in water. PMID:27491849

  7. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < ‑1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  8. Negative effects of positive reinforcement

    PubMed Central

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive—those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures. ImagesFigure 1Figure 2 PMID:22478391

  9. Negative effects of positive reinforcement.

    PubMed

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive-those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures.

  10. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < -1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  11. Biomimetic Production of Hydrogen

    NASA Astrophysics Data System (ADS)

    Gust, Devens

    2004-03-01

    The basic reaction for hydrogen generation is formation of molecular hydrogen from two electrons and two protons. Although there are many possible sources for the protons and electrons, and a variety of mechanisms for providing the requisite energy for hydrogen synthesis, the most abundant and readily available source of protons and electrons is water, and the most attractive source of energy for powering the process is sunlight. Not surprisingly, living systems have evolved to take advantage of these sources for materials and energy. Thus, biology provides paradigms for carrying out the reactions necessary for hydrogen production. Photosynthesis in green plants uses sunlight as the source of energy for the oxidation of water to give molecular oxygen, protons, and reduction potential. Some photosynthetic organisms are capable of using this reduction potential, in the form of the reduced redox protein ferredoxin, to reduce protons and produce molecular hydrogen via the action of an hydrogenase enzyme. A variety of other organisms metabolize the reduced carbon compounds that are ultimately the major products of photosynthesis to produce molecular hydrogen. These facts suggest that it might be possible to use light energy to make molecular hydrogen via biomimetic constructs that employ principles similar to those used by natural organisms, or perhaps with hybrid "bionic" systems that combine biomimetic materials with natural enzymes. It is now possible to construct artificial photosynthetic systems that mimic some of the major steps in the natural process.(1) Artificial antennas based on porphyrins, carotenoids and other chromophores absorb light at various wavelengths in the solar spectrum and transfer the harvested excitation energy to artificial photosynthetic reaction centers.(2) In these centers, photoinduced electron transfer uses the energy from light to move an electron from a donor to an acceptor moiety, generating a high-energy charge-separated state

  12. In defense of negative temperature

    NASA Astrophysics Data System (ADS)

    Poulter, J.

    2016-03-01

    This pedagogical comment highlights three misconceptions concerning the usefulness of the concept of negative temperature, being derived from the usual, often termed Boltzmann, definition of entropy. First, both the Boltzmann and Gibbs entropies must obey the same thermodynamic consistency relation. Second, the Boltzmann entropy does obey the second law of thermodynamics. Third, there exists an integrating factor of the heat differential with both definitions of entropy.

  13. In defense of negative temperature.

    PubMed

    Poulter, J

    2016-03-01

    This pedagogical comment highlights three misconceptions concerning the usefulness of the concept of negative temperature, being derived from the usual, often termed Boltzmann, definition of entropy. First, both the Boltzmann and Gibbs entropies must obey the same thermodynamic consistency relation. Second, the Boltzmann entropy does obey the second law of thermodynamics. Third, there exists an integrating factor of the heat differential with both definitions of entropy. PMID:27078334

  14. Solar hydrogen production: renewable hydrogen production by dry fuel reforming

    NASA Astrophysics Data System (ADS)

    Bakos, Jamie; Miyamoto, Henry K.

    2006-09-01

    SHEC LABS - Solar Hydrogen Energy Corporation constructed a pilot-plant to demonstrate a Dry Fuel Reforming (DFR) system that is heated primarily by sunlight focusing-mirrors. The pilot-plant consists of: 1) a solar mirror array and solar concentrator and shutter system; and 2) two thermo-catalytic reactors to convert Methane, Carbon Dioxide, and Water into Hydrogen. Results from the pilot study show that solar Hydrogen generation is feasible and cost-competitive with traditional Hydrogen production. More than 95% of Hydrogen commercially produced today is by the Steam Methane Reformation (SMR) of natural gas, a process that liberates Carbon Dioxide to the atmosphere. The SMR process provides a net energy loss of 30 to 35% when converting from Methane to Hydrogen. Solar Hydrogen production provides a 14% net energy gain when converting Methane into Hydrogen since the energy used to drive the process is from the sun. The environmental benefits of generating Hydrogen using renewable energy include significant greenhouse gas and criteria air contaminant reductions.

  15. [Alexithymia in negative symptom and non-negative symptom schizophrenia].

    PubMed

    Nkam, I; Langlois-Thery, S; Dollfus, S; Petit, M

    1997-01-01

    Coined by Sifneos in 1972, alexithymia refers to a relative narrowing in emotional functioning, an inability to find appropriate words to describe their emotions and, a poverty of fantasy life. Although initially described in the context of psychosomatic illness, alexithymic characteristics may be observed in patients with a wide range of medical and psychiatric disorders: Parkinson disease, depression, anxiety, substance abuse and eating disorders. Flattening of affect and poverty of speech, major negative symptoms, referred to chronic schizophrenia: there is a lack of outward display of emotion. Accordingly, some disturbances of alexithymia's scores would be expected in schizophrenic patients. The purpose of this study was to estimate and compare the prevalence of alexithymia in deficit and non-deficit schizophrenia. The term "deficit symptoms" may be used as Carpenter, to refer specifically to those negative symptoms that are not considered secondary. The influence of patients' symptoms has also been studied on alexithymia scores: negative and positive symptoms of schizophrenia, depression, anxiety, anhedonia and effects of neuroleptics. Twenty-five patients, meeting DSM III-R criteria for schizophrenia have been studied. All of them treated by neuroleptics, were in a stable clinical status for at least one month. The patients have been categorized into deficit (n = 12) and non-deficit (n = 13) subgroups by one trained psychiatrist (SD), using the Schedule for the Deficit Syndrome. The subjects have been assessed by the same rater (IN), blind to deficit status, using six rating scales: Beth Israel Questionnaire (BIQ) and Toronto Alexithymia Scale (TAS) for alexithymia, Positive and Negative Syndrome Scale (PANSS), Montgomery and Asberg Depression Rating Scale (MADRS), revised Physical Anhedonia Scale (PAS), and finally, Extrapyramidal Symptom Rating Scale (ESRS). Using TAS, alexithymic characteristics were more prevalent in the deficit subgroup as compared to

  16. Hydrogen-enriched fuels

    SciTech Connect

    Roser, R.

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  17. Hydrogen arcjet technology

    NASA Technical Reports Server (NTRS)

    Sankovic, John M.; Hamley, John A.; Haag, Thomas W.; Sarmiento, Charles J.; Curran, Francis M.

    1991-01-01

    During the 1960's, a substantial research effort was centered on the development of arcjets for space propulsion applications. The majority of the work was at the 30 kW power level with some work at 1-2 kW. At the end of the research effort, the hydrogen arcjet had demonstrated over 700 hours of life in a continuous endurance test at 30 kW, at a specific impulse over 1000 s, and at an efficiency of 0.41. Another high power design demonstrated 500 h life with an efficiency of over 0.50 at the same specific impulse and power levels. At lower power levels, a life of 150 hours was demonstrated at 2 kW with an efficiency of 0.31 and a specific impulse of 935 s. Lack of a space power source hindered arcjet acceptance and research ceased. Over three decades after the first research began, renewed interest exists for hydrogen arcjets. The new approach includes concurrent development of the power processing technology with the arcjet thruster. Performance data were recently obtained over a power range of 0.3-30 kW. The 2 kW performance has been repeated; however, the present high power performance is lower than that obtained in the 1960's at 30 kW, and lifetimes of present thrusters have not yet been demonstrated. Laboratory power processing units have been developed and operated with hydrogen arcjets for the 0.1 kW to 5 kW power range. A 10 kW power processing unit is under development and has been operated at design power into a resistive load.

  18. Leak Detection and H2 Sensor Development for Hydrogen Applications

    SciTech Connect

    Brosha, Eric L.

    2012-07-10

    The objectives of this report are: (1) Develop a low cost, low power, durable, and reliable hydrogen safety sensor for a wide range of vehicle and infrastructure applications; (2) Continually advance test prototypes guided by materials selection, sensor design, electrochemical R&D investigation, fabrication, and rigorous life testing; (3) Disseminate packaged sensor prototypes and control systems to DOE Laboratories and commercial parties interested in testing and fielding advanced prototypes for cross-validation; (4) Evaluate manufacturing approaches for commercialization; and (5) Engage an industrial partner and execute technology transfer. Recent developments in the search for sustainable and renewable energy coupled with the advancements in fuel cell powered vehicles (FCVs) have augmented the demand for hydrogen safety sensors. There are several sensor technologies that have been developed to detect hydrogen, including deployed systems to detect leaks in manned space systems and hydrogen safety sensors for laboratory and industrial usage. Among the several sensing methods electrochemical devices that utilize high temperature-based ceramic electrolytes are largely unaffected by changes in humidity and are more resilient to electrode or electrolyte poisoning. The desired sensing technique should meet a detection threshold of 1% (10,000 ppm) H{sub 2} and response time of {approx_equal}1 min, which is a target for infrastructure and vehicular uses. Further, a review of electrochemical hydrogen sensors by Korotcenkov et.al and the report by Glass et.al suggest the need for inexpensive, low power, and compact sensors with long-term stability, minimal cross-sensitivity, and fast response. This view has been largely validated and supported by the fuel cell and hydrogen infrastructure industries by the NREL/DOE Hydrogen Sensor Workshop held on June 8, 2011. Many of the issues preventing widespread adoption of best-available hydrogen sensing technologies available today

  19. Cesium Delivery System for Negative Ion Source at IPR

    SciTech Connect

    Bansal, G.; Pandya, K.; Soni, J.; Gahlaut, A.; Parmar, K. G.; Bandyopadhyay, M.; Chakraborty, A.; Singh, M. J.

    2011-09-26

    The technique of surface production of negative ions using cesium, Cs, has been efficiently exploited over the years for producing negative ion beams with increased current densities from negative ion sources used on neutral beam lines. Deposition of Cs on the source walls and the plasma grid lowers the work function and therefore enables a higher yield of H{sup -}, when hydrogen particles (H and/or H{sub x}{sup +}) strike these surfaces.A single driver RF based (100 kW, 1 MHz) negative ion source test bed, ROBIN, is being set up at IPR under a technical collaboration between IPR and IPP, Germany. The optimization of the Cs oven design to be used on this facility as well as multidriver sources is underway. The characterization experiments of such a Cs delivery system with a 1 g Cs inventory have been carried out using surface ionization technique. The experiments have been carried by delivering Cs into a vacuum chamber without plasma. The linear motion of the surface ionization detector, SID, attached with a linear motion feedthrough allows measuring the angular distribution of the Cs coming out of the oven. Based on the experimental results, a Cs oven for ROBIN has been proposed. The Cs oven design and experimental results of the prototype Cs oven are reported and discussed in the paper.

  20. First experiments with the negative ion source NIO1.

    PubMed

    Cavenago, M; Serianni, G; De Muri, M; Agostinetti, P; Antoni, V; Baltador, C; Barbisan, M; Baseggio, L; Bigi, M; Cervaro, V; Degli Agostini, F; Fagotti, E; Kulevoy, T; Ippolito, N; Laterza, B; Minarello, A; Maniero, M; Pasqualotto, R; Petrenko, S; Poggi, M; Ravarotto, D; Recchia, M; Sartori, E; Sattin, M; Sonato, P; Taccogna, F; Variale, V; Veltri, P; Zaniol, B; Zanotto, L; Zucchetti, S

    2016-02-01

    Neutral Beam Injectors (NBIs), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact radio frequency (rf) ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H(-) current of 130 mA, 60 kV acceleration voltage, was installed at Consorzio RFX, including a high voltage deck and an X-ray shield, to provide a test bench for source optimizations for activities in support to the ITER NBI test facility. NIO1 status and plasma experiments both with air and with hydrogen as filling gas are described. Transition from a weak plasma to an inductively coupled plasma is clearly evident for the former gas and may be triggered by rising the rf power (over 0.5 kW) at low pressure (equal or below 2 Pa). Transition in hydrogen plasma requires more rf power (over 1.5 kW). PMID:26932048

  1. Trapping and spectroscopy of hydrogen

    NASA Astrophysics Data System (ADS)

    Cesar, Claudio Lenz

    1997-08-01

    I review the results and techniques used by the MIT H↑ group to achieve a fractional resolution of 2 parts in 1012 in the 1S-2S transition in hydrogen [Cesar, D. Fried, T. Killian, A. Polcyn, J. Sandberg, I.A. Yu, T. Greytak, D. Kleppner and J. Doyle, Two-photon spectroscopy of trapped atomic hydrogen, Phys. Rev. Lett. 77 (1996) 255.] With some improvements, this system should deliver 100 times higher resolution with an improved signal count rate getting us closer to an old advertised goal of a precision of 1 part in 1018. While these developments are very important for the proposed test of the CPT theorem through the comparison with anti-hydrogen, some of the techniques used with hydrogen are not applicable to anti-hydrogen and I discuss some difficulties and alternatives for the trapping and spectroscopy of anti-hydrogen.

  2. Hydrogen ICE Vehicle Testing Activities

    SciTech Connect

    J. Francfort; D. Karner

    2006-04-01

    The Advanced Vehicle Testing Activity teamed with Electric Transportation Applications and Arizona Public Service to develop and monitor the operations of the APS Alternative Fuel (Hydrogen) Pilot Plant. The Pilot Plant provides 100% hydrogen, and hydrogen and compressed natural gas (H/CNG)-blended fuels for the evaluation of hydrogen and H/CNG internal combustion engine (ICE) vehicles in controlled and fleet testing environments. Since June 2002, twenty hydrogen and H/CNG vehicles have accumulated 300,000 test miles and 5,700 fueling events. The AVTA is part of the Department of Energy’s FreedomCAR and Vehicle Technologies Program. These testing activities are managed by the Idaho National Laboratory. This paper discusses the Pilot Plant design and monitoring, and hydrogen ICE vehicle testing methods and results.

  3. Hydrogen from renewable resources research

    SciTech Connect

    Takahashi, P.K.; McKinley, K.R.

    1990-07-01

    In 1986 the Hawaii Natural Energy Institute (HNEI) and the Florida Solar Energy Center (FSEC) were contracted by the Solar Energy Research Institute (SERI) to conduct an assessment of hydrogen production technologies and economic feasibilities of the production and use of hydrogen from renewable resources. In the 1989/90 period all monies were directed toward research and development with an emphasis on integration of tasks, focusing on two important issues, production and storage. The current year's efforts consisted of four tasks, one task containing three subtasks: Hydrogen Production by Gasification of Glucose and Wet Biomass in Supercritical Water; Photoelectrochemical Production of Hydrogen; Photoemission and Photoluminescence Studies of Catalyzed Photoelectrode Surfaces for Hydrogen Production; Solar Energy Chemical Conversion by Means of Photoelectrochemical (PEC) Methods Using Coated Silicon Electrodes; Assessment of Impedance Spectroscopy Methods for Evaluation of Semiconductor-Electrolyte Interfaces; Solar Energy Conversion with Cyanobacteria; Nonclassical Polyhydride Metal Complexes as Hydrogen Storage Materials. 61 refs., 22 figs., 11 tabs.

  4. Liquid Hydrogen Absorber for MICE

    SciTech Connect

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing

    2010-05-30

    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  5. Thermochemical generation of hydrogen

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R. (Inventor)

    1982-01-01

    The direct fluid contact heat exchange with H2SO4 at about 330 C prior to high temperature decomposition at about 830 C in the oxygen release step of several thermochemical cycles for splitting water into hydrogen and oxygen provides higher heat transfer rates, savings in energy and permits use of cast vessels rather than expensive forged alloy indirect heat exchangers. Among several candidate perfluorocarbon liquids tested, only perfluoropropylene oxide polymers having a degree of polymerization from about 10 to 60 were chemically stable, had low miscibility and vapor pressure when tested with sulfuric acid at temperatures from 300 C to 400 C.

  6. Hydrogen storage development

    SciTech Connect

    Thomas, G.J.; Guthrie, S.E.

    1998-08-01

    A summary of the hydride development efforts for the current program year (FY98) are presented here. The Mg-Al-Zn alloy system was studied at low Zn levels (2--4 wt%) and midrange Al contents (40--60 wt%). Higher plateau pressures were found with Al and Zn alloying in Mg and, furthermore, it was found that the hydrogen desorption kinetics were significantly improved with small additions of Zn. Results are also shown here for a detailed study of the low temperature properties of Mg{sub 2}NiH{sub 4}, and a comparison made between conventional melt cast alloy and the vapor process material.

  7. Hydrogen-Antihydrogen Collisions

    SciTech Connect

    Froelich, P.; Jonsell, S.; Saenz, A.; Zygelman, B.; Dalgarno, A.

    2000-05-15

    Matter-antimatter interactions are investigated using hydrogen-antihydrogen collisions as an example. Cross sections for elastic scattering and for the antihydrogen loss (either through the rearrangement reaction, resulting in formation of protonium and positronium according to H+H(bar sign){yields}p p(bar sign)+e{sup +}e{sup -} , or via annihilation in flight) are calculated for the first time in a fully quantum mechanical approach. Implications for experiments intending to trap and cool antihydrogen are discussed. (c) 2000 The American Physical Society.

  8. Hydrogen aircraft technology

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.

    1991-01-01

    A comprehensive evaluation is conducted of the technology development status, economics, commercial feasibility, and infrastructural requirements of LH2-fueled aircraft, with additional consideration of hydrogen production, liquefaction, and cryostorage methods. Attention is given to the effects of LH2 fuel cryotank accommodation on the configurations of prospective commercial transports and military airlifters, SSTs, and HSTs, as well as to the use of the plentiful heatsink capacity of LH2 for innovative propulsion cycles' performance maximization. State-of-the-art materials and structural design principles for integral cryotank implementation are noted, as are airport requirements and safety and environmental considerations.

  9. System for Hydrogen Sensing

    NASA Technical Reports Server (NTRS)

    Lin, Jenshan; Norton, David P.; Pearton, Stephen J.; Ren, Fan

    2010-01-01

    A low-power, wireless gas-sensing system is designed to safeguard the apparatus to which it is attached, as well as associated personnel. It also ensures the efficiency and operational integrity of the hydrogen-powered apparatus. This sensing system can be operated with lower power consumption (less than 30 nanowatts), but still has a fast response. The detecting signal can be wirelessly transmitted to remote locations, or can be posted on the Web. This system can also be operated by harvesting energy.

  10. Hydrogen Storage in Diamond Powder Utilizing Plasma NaF Surface Treatment for Fuel Cell Applications

    SciTech Connect

    Leal, David A.; Leal-Quiros, E.; Velez, Angel; Prelas, Mark A.; Gosh, Tushar

    2006-12-04

    Hydrogen Fuel Cells offer the vital solution to the world's socio-political dependence on oil. Due to existing difficulty in safe and efficient hydrogen storage for fuel cells, storing the hydrogen in hydrocarbon compounds such as artificial diamond is a realistic solution. By treating the surface of the diamond powder with a Sodium Fluoride plasma exposure, the surface of the diamond is cleaned of unwanted molecules. Due to fluorine's electro negativity, the diamond powder is activated and ready for hydrogen absorption. These diamond powder pellets are then placed on a graphite platform that is heated by conduction in a high voltage circuit made of tungsten wire. Then, the injection of hydrogen gas into chamber allows the storage of the Hydrogen on the surface of the diamond powder. By neutron bombardment in the nuclear reactor, or Prompt Gamma Neutron Activation Analysis, the samples are examined for parts per million amounts of hydrogen in the sample. Sodium Fluoride surface treatment allows for higher mass percentage of stored hydrogen in a reliable, resistant structure, such as diamond for fuel cells and permanently alters the diamonds terminal bonds for re-use in the effective storage of hydrogen. The highest stored amount utilizing the NaF plasma surface treatment was 22229 parts per million of hydrogen in the diamond powder which amounts to 2.2229% mass increase.

  11. Hydrogen desorption kinetics for aqueous hydrogen fluoride and remote hydrogen plasma processed silicon (001) surfaces

    SciTech Connect

    King, Sean W. Davis, Robert F.; Carter, Richard J.; Schneider, Thomas P.; Nemanich, Robert J.

    2015-09-15

    The desorption kinetics of molecular hydrogen (H{sub 2}) from silicon (001) surfaces exposed to aqueous hydrogen fluoride and remote hydrogen plasmas were examined using temperature programmed desorption. Multiple H{sub 2} desorption states were observed and attributed to surface monohydride (SiH), di/trihydride (SiH{sub 2/3}), and hydroxide (SiOH) species, subsurface hydrogen trapped at defects, and hydrogen evolved during the desorption of surface oxides. The observed surface hydride species were dependent on the surface temperature during hydrogen plasma exposure with mono, di, and trihydride species being observed after low temperature exposure (150 °C), while predominantly monohydride species were observed after higher temperature exposure (450 °C). The ratio of surface versus subsurface H{sub 2} desorption was also found to be dependent on the substrate temperature with 150 °C remote hydrogen plasma exposure generally leading to more H{sub 2} evolved from subsurface states and 450 °C exposure leading to more H{sub 2} desorption from surface SiH{sub x} species. Additional surface desorption states were observed, which were attributed to H{sub 2} desorption from Si (111) facets formed as a result of surface etching by the remote hydrogen plasma or aqueous hydrogen fluoride treatment. The kinetics of surface H{sub 2} desorption were found to be in excellent agreement with prior investigations of silicon surfaces exposed to thermally generated atomic hydrogen.

  12. National Hydrogen Roadmap Workshop Proceedings

    SciTech Connect

    2002-04-01

    This document summarizes the presentations and suggestions put forth by officials, industry experts and policymakers in their efforts to come together to develop a roadmap for America''s clean energy future and outline the key barriers and needs to achieve the hydrogen vision. The National Hydrogen Roadmap Workshop was held April 2-3, 2002. These proceedings were compiled into a formal report, The National Hydrogen Energy Roadmap, which is also available online.

  13. Complex hydrides for hydrogen storage

    DOEpatents

    Zidan, Ragaiy

    2006-08-22

    A hydrogen storage material and process of forming the material is provided in which complex hydrides are combined under conditions of elevated temperatures and/or elevated temperature and pressure with a titanium metal such as titanium butoxide. The resulting fused product exhibits hydrogen desorption kinetics having a first hydrogen release point which occurs at normal atmospheres and at a temperature between 50.degree. C. and 90.degree. C.

  14. Installation of spectrally selective imaging system in RF negative ion source.

    PubMed

    Ikeda, K; Wünderlich, D; Fantz, U; Heinemann, B; Kisaki, M; Nagaoka, K; Nakano, H; Osakabe, M; Tsumori, K; Geng, S; Kaneko, O; Takeiri, Y

    2016-02-01

    A spectrally selective imaging system has been installed in the RF negative ion source in the International Thermonuclear Experimental Reactor-relevant negative ion beam test facility ELISE (Extraction from a Large Ion Source Experiment) to investigate distribution of hydrogen Balmer-α emission (Hα) close to the production surface of hydrogen negative ion. We selected a GigE vision camera coupled with an optical band-path filter, which can be controlled remotely using high speed network connection. A distribution of Hα emission near the bias plate has been clearly observed. The same time trend on Hα intensities measured by the imaging diagnostic and the optical emission spectroscopy is confirmed. PMID:26931995

  15. On the formation and destruction of chlorine negative ions in the D region

    NASA Technical Reports Server (NTRS)

    Turco, R. P.

    1977-01-01

    We have investigated the possible reactions of chlorine atoms, chlorine monoxide, and hydrogen chloride with D region negative ions. The mesospheric concentrations of the neutral chlorine gases have been predicted with a diurnally varying one-dimensional model of the upper atmosphere. Despite the low abundances of chlorine compounds in air their high reactivity leads to the formation of substantial quantities of clorine negative ions at high altitudes. The concentration of chlorine ions is limited in daylight by rapid reactions with oxygen and hydrogen atoms and at night by the competitive production of other stable ions. The presence of chlorine negative ions in the upper atmosphere is consistent with in situ mass spectrometer observations of charged species. The abundance of chlorinated ions in the D region may be correlated with mesospheric nitric oxide and water vapor concentrations.

  16. Hydrogen Technology Research at SRNL

    SciTech Connect

    Danko, E.

    2011-02-13

    The Savannah River National Laboratory (SRNL) is a U.S. Department of Energy research and development laboratory located at the Savannah River Site (SRS) near Aiken, South Carolina. SRNL has over 50 years of experience in developing and applying hydrogen technology, both through its national defense activities as well as through its recent activities with the DOE Hydrogen Programs. The hydrogen technical staff at SRNL comprises over 90 scientists, engineers and technologists. SRNL has ongoing R&D initiatives in a variety of hydrogen storage areas, including metal hydrides, complex hydrides, chemical hydrides and carbon nanotubes. SRNL has over 25 years of experience in metal hydrides and solid-state hydrogen storage research, development and demonstration. As part of its defense mission at SRS, SRNL developed, designed, demonstrated and provides ongoing technical support for the largest hydrogen processing facility in the world based on the integrated use of metal hydrides for hydrogen storage, separation, and compression. The SRNL has been active in teaming with academic and industrial partners to advance hydrogen technology. A primary focus of SRNL's R&D has been hydrogen storage using metal and complex hydrides. SRNL and its Hydrogen Technology Research Laboratory have been very successful in leveraging their defense infrastructure, capabilities and investments to help solve this country's energy problems. SRNL has participated in projects to convert public transit and utility vehicles for operation using hydrogen fuel. Two major projects include the H2Fuel Bus and an Industrial Fuel Cell Vehicle (IFCV) also known as the GATOR{trademark}. Both of these projects were funded by DOE and cost shared by industry. These are discussed further in Section 3.0, Demonstration Projects. In addition to metal hydrides technology, the SRNL Hydrogen group has done extensive R&D in other hydrogen technologies, including membrane filters for H2 separation, doped carbon nanotubes

  17. Hydrogen production costs -- A survey

    SciTech Connect

    Basye, L.; Swaminathan, S.

    1997-12-04

    Hydrogen, produced using renewable resources, is an environmentally benign energy carrier that will play a vital role in sustainable energy systems. The US Department of Energy (DOE) supports the development of cost-effective technologies for hydrogen production, storage, and utilization to facilitate the introduction of hydrogen in the energy infrastructure. International interest in hydrogen as an energy carrier is high. Research, development, and demonstration (RD and D) of hydrogen energy systems are in progress in many countries. Annex 11 of the International Energy Agency (IEA) facilitates member countries to collaborate on hydrogen RD and D projects. The United States is a member of Annex 11, and the US representative is the Program Manager of the DOE Hydrogen R and D Program. The Executive Committee of the Hydrogen Implementing Agreement in its June 1997 meeting decided to review the production costs of hydrogen via the currently commercially available processes. This report compiles that data. The methods of production are steam reforming, partial oxidation, gasification, pyrolysis, electrolysis, photochemical, photobiological, and photoelectrochemical reactions.

  18. Hydrogen embrittlement of structural steels.

    SciTech Connect

    Somerday, Brian P.

    2010-06-01

    Carbon-manganese steels are candidates for the structural materials in hydrogen gas pipelines, however it is well known that these steels are susceptible to hydrogen embrittlement. Decades of research and industrial experience have established that hydrogen embrittlement compromises the structural integrity of steel components. This experience has also helped identify the failure modes that can operate in hydrogen containment structures. As a result, there are tangible ideas for managing hydrogen embrittement in steels and quantifying safety margins for steel hydrogen containment structures. For example, fatigue crack growth aided by hydrogen embrittlement is a key failure mode for steel hydrogen containment structures subjected to pressure cycling. Applying appropriate structural integrity models coupled with measurement of relevant material properties allows quantification of safety margins against fatigue crack growth in hydrogen containment structures. Furthermore, application of these structural integrity models is aided by the development of micromechanics models, which provide important insights such as the hydrogen distribution near defects in steel structures. The principal objective of this project is to enable application of structural integrity models to steel hydrogen pipelines. The new American Society of Mechanical Engineers (ASME) B31.12 design code for hydrogen pipelines includes a fracture mechanics-based design option, which requires material property inputs such as the threshold for rapid cracking and fatigue crack growth rate under cyclic loading. Thus, one focus of this project is to measure the rapid-cracking thresholds and fatigue crack growth rates of line pipe steels in high-pressure hydrogen gas. These properties must be measured for the base materials but more importantly for the welds, which are likely to be most vulnerable to hydrogen embrittlement. The measured properties can be evaluated by predicting the performance of the pipeline

  19. Catalyzed borohydrides for hydrogen storage

    DOEpatents

    Au, Ming

    2012-02-28

    A hydrogen storage material and process is provided in which alkali borohydride materials are created which contain effective amounts of catalyst(s) which include transition metal oxides, halides, and chlorides of titanium, zirconium, tin, and combinations of the various catalysts. When the catalysts are added to an alkali borodydride such as a lithium borohydride, the initial hydrogen release point of the resulting mixture is substantially lowered. Additionally, the hydrogen storage material may be rehydrided with weight percent values of hydrogen at least about 9 percent.

  20. Hydrogen fracture toughness tester completion

    SciTech Connect

    Morgan, Michael J.

    2015-09-30

    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.