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Sample records for hydrogen balmer emission

  1. Hydrogen recycling study by Balmer lines emissions in linear plasma machine TPE

    NASA Astrophysics Data System (ADS)

    Shimada, K.; Tanabe, T.; Causey, R.; Venhaus, T.; Okuno, K.

    2001-03-01

    We have investigated the influence of target materials and temperatures on Balmer series emission in a linear plasma apparatus, Tritium Plasma Experiment (TPE). The intensities of the Balmer series emission in front of the target were higher for heavier mass target and also for lower target temperature, showing rather linear relationship between the emission intensity and hydrogen reflection coefficient. For exothermic hydrogen occluders of Ti and Ta, the intensity ratio of Dβ/ Dα increased with the target temperature markedly, whereas the intensity ratio stayed rather constant for endothermic hydrogen occluders of Ni, Cu and W. This is a clear demonstration that the target materials and temperatures modify the boundary plasma. In addition the intensity ratio Dβ/Dα is not simply a function of plasma temperature but has clear target temperature dependence.

  2. Resolution of the discrepancy between Balmer alpha emission rates, the solar Lyman beta flux, and models of geocoronal hydrogen concentration

    NASA Technical Reports Server (NTRS)

    Levasseur, A.-C.; Meier, R. R.; Tinsley, B. A.

    1976-01-01

    New satellite Balmer alpha measurements and solar Lyman beta flux and line profile measurements, together with new measurements of the zodiacal light intensity used in correcting both ground and satellite Balmer alpha measurements for the effects of the Fraunhofer line in the zodiacal light, have been used in a reevaluation of the long-standing discrepancy between ground-based Balmer alpha emission rates and other geocoronal hydrogen parameters. The solar Lyman beta line center flux is found to be (4.1 plus or minus 1.3) billion photons per sq cm per sec per angstrom at S(10.7) equals 110 and, together with a current hydrogen model which has 92,000 atoms per cu cm at 650 km for T(inf) equals 950 K, gives good agreement between calculated Balmer alpha emission rates and the ground-based and satellite measurements.

  3. Simultaneous measurements of the hydrogen airglow emissions of Lyman alpha, Lyman beta, and Balmer alpha.

    NASA Technical Reports Server (NTRS)

    Weller, C. S.; Meier, R. R.; Tinsley, B. A.

    1971-01-01

    Comparison of Lyman-alpha, 740- to 1050-A, and Balmer-alpha airglow measurements made at 134 deg solar-zenith angle on Oct. 13, 1969, with resonance-scattering models of solar radiation. Model comparison with Lyman-alpha data fixes the hydrogen column abundance over 215 km to 2 x 10 to the 13th per cu cm within a factor of 2. Differences between the Lyman-alpha model and data indicate a polar-equatorial departure from spherical symmetry in the hydrogen distribution. A Lyman-beta model based on the hydrogen distribution found to fit the Lyman-alpha data fits the spatial variation of the 740- to 1050-A data well from 100 to 130 km, but it does not fit the data well at higher altitudes; thus the presence of more rapidly absorbed shorter-wavelength radiation is indicated. This same resonance-scattering model yields Balmer-alpha intensities that result in good spatial agreement with the Balmer-alpha measurements, but a fivefold increase in the measured solar line center Lyman-beta flux is required (as required for the Lyman-beta measurement). The intensity ratio of Lyman-beta and Balmer-alpha at night is found to be a simple measure of the hydrogen optical depth if measurements with good accuracy can be made in the visible and ultraviolet spectrum.

  4. 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.

  5. Collisionless Shocks in a Partially Ionized Medium. II. Balmer Emission

    NASA Astrophysics Data System (ADS)

    Morlino, G.; Bandiera, R.; Blasi, P.; Amato, E.

    2012-12-01

    Strong shocks propagating into a partially ionized medium are often associated with optical Balmer lines. This emission is due to impact excitation of neutral hydrogen by hot protons and electrons in the shocked gas. The structure of such Balmer-dominated shocks has been computed in a previous paper, where the distribution function of neutral particles was derived from the appropriate Boltzmann equation including coupling with ions and electrons through charge exchange and ionization. This calculation showed how the presence of neutrals can significantly modify the shock structure through the formation of a neutral-induced precursor ahead of the shock. Here we follow up on our previous work and investigate the properties of the resulting Balmer emission, with the aim of using the observed radiation as a diagnostic tool for shock parameters. Our main focus is on supernova remnant shocks, and we find that, for typical parameters, the Hα emission typically has a three-component spectral profile, where (1) a narrow component originates from upstream cold hydrogen atoms, (2) a broad component comes from hydrogen atoms that have undergone charge exchange with shocked protons downstream of the shock, and (3) an intermediate component is due to hydrogen atoms that have undergone charge exchange with warm protons in the neutral-induced precursor. The relative importance of these three components depends on the shock velocity, on the original degree of ionization, and on the electron-ion temperature equilibration level. The intermediate component, which is the main signature of the presence of a neutral-induced precursor, becomes negligible for shock velocities <~ 1500 km s-1. The width of the intermediate line reflects the temperature in the precursor, while the width of the narrow one is left unaltered by the precursor. In addition, we show that the profiles of both the intermediate and broad components generally depart from a thermal distribution, as a consequence of the

  6. Theoretical quasar emission-line ratios. V - Balmer continuum emission

    NASA Technical Reports Server (NTRS)

    Puetter, R. C.; Levan, P. D.

    1982-01-01

    Isothermal, isobaric models of quasar emission line regions are presented which include an improved treatment of radiative transfer in the bound-free continua, based on a generalization of frequency-integrated line transfer techniques and on the use of a probabilistic radiative transfer equation which explicitly distinguishes between the flux divergence coefficient and the photon escape probability. It is found that Balmer continuum emission can be obtained without compromising observed line ratios. It is also established that optically thin or thick Balmer continuum emission models with blended Fe II line are consistent with 4000-2000 A 'blue bump' observations, and that the improved radiative transfer treatment makes order-of-magnitude corrections to level populations and local cooling rates calculated with past techniques.

  7. Self-broadening of the hydrogen Balmer α line

    NASA Astrophysics Data System (ADS)

    Allard, N. F.; Kielkopf, J. F.; Cayrel, R.; van't Veer-Menneret, C.

    2008-03-01

    Context: Profiles of hydrogen lines in stellar spectra are determined by the properties of the hydrogen atom and the structure of the star's atmosphere. Hydrogen line profiles are therefore a very important diagnostic tool in stellar modeling. In particular they are widely used as effective temperature criterion for stellar atmospheres in the range T_eff 5500-7000 K. Aims: In cool stars such as the Sun hydrogen is largely neutral and the electron density is low. The line center width at half maximum and the spectral energy distribution in the wings are determined primarily by collisions with hydrogen atoms due to their high relative density. This work aims to provide benchmark calculations of Balmer α based on recent H2 potentials. Methods: For the first time an accurate determination of the broadening of Balmer α by atomic hydrogen is made in a unified theory of collisional line profiles using ab initio calculations of molecular hydrogen potential energies and transition matrix elements among singlet and triplet electronic states. Results: We computed the shape, width and shift of the Balmer α line perturbed by neutral hydrogen and studied their dependence on temperature. We present results over the full range of temperatures from 3000 to 12 000 K needed for stellar spectra models. Conclusions: Our calculations lead to larger values than those obtained with the commonly used Ali & Griem (1966, Phys. Rev. A, 144, 366) theory and are closer to the recent calculations of Barklem et al. (2000a, A&A, 355, L5; 2000b, A&A, 363, 1091). We conclude that the line parameters are dependent on the sum of many contributing molecular transitions, each with a different temperature dependence, and we provide tables for Balmer α. The unified line shape theory with complete molecular potentials also predicts additional opacity in the far non-Lorentzian wing.

  8. HYDROGEN BALMER CONTINUUM IN SOLAR FLARES DETECTED BY THE INTERFACE REGION IMAGING SPECTROGRAPH (IRIS)

    SciTech Connect

    Heinzel, P.; Kleint, L.

    2014-10-20

    We present a novel observation of the white light flare (WLF) continuum, which was significantly enhanced during the X1 flare on 2014 March 29 (SOL2014-03-29T17:48). Data from the Interface Region Imaging Spectrograph (IRIS) in its near-UV channel show that at the peak of the continuum enhancement, the contrast at the quasi-continuum window above 2813 Å reached 100%-200% and can be even larger closer to Mg II lines. This is fully consistent with the hydrogen recombination Balmer-continuum emission, which follows an impulsive thermal and non-thermal ionization caused by the precipitation of electron beams through the chromosphere. However, a less probable photospheric continuum enhancement cannot be excluded. The light curves of the Balmer continuum have an impulsive character with a gradual fading, similar to those detected recently in the optical region on the Solar Optical Telescope on board Hinode. This observation represents a first Balmer-continuum detection from space far beyond the Balmer limit (3646 Å), eliminating seeing effects known to complicate the WLF detection. Moreover, we use a spectral window so far unexplored for flare studies, which provides the potential to study the Balmer continuum, as well as many metallic lines appearing in emission during flares. Combined with future ground-based observations of the continuum near the Balmer limit, we will be able to disentangle various scenarios of the WLF origin. IRIS observations also provide a critical quantitative measure of the energy radiated in the Balmer continuum, which constrains various models of the energy transport and deposit during flares.

  9. Laser-induced plasma spectroscopy of hydrogen Balmer series in laboratory air.

    PubMed

    Swafford, Lauren D; Parigger, Christian G

    2014-01-01

    Stark-broadened emission profiles for the hydrogen alpha and beta Balmer series lines in plasma are measured to characterize electron density and temperature. Plasma is generated using a typical laser-induced breakdown spectroscopy (LIBS) arrangement that employs a focused Q-switched neodymium-doped yttrium aluminum garnet (Nd : YAG) laser, operating at the fundamental wavelength of 1064 nm. The temporal evolution of the hydrogen Balmer series lines is explored using LIBS. Spectra from the plasma are measured following laser-induced optical breakdown in laboratory air. The electron density is primarily inferred from the Stark-broadened experimental data collected at various time delays. Due to the presence of nitrogen and oxygen in air, the hydrogen alpha and beta lines become clearly discernible from background radiation for time delays of 0.4 and 1.4 μs, respectively. PMID:25226255

  10. A Guided-Inquiry Lab for the Analysis of the Balmer Series of the Hydrogen Atomic Spectrum

    ERIC Educational Resources Information Center

    Bopegedera, A. M. R. P.

    2011-01-01

    A guided-inquiry lab was developed to analyze the Balmer series of the hydrogen atomic spectrum. The emission spectrum of hydrogen was recorded with a homemade benchtop spectrophotometer. By drawing graphs and a trial-and-error approach, students discover the linear relationship presented in the Rydberg formula and connect it with the Bohr model…

  11. Hydrogen Balmer line formation in solar flares affected by return currents

    NASA Astrophysics Data System (ADS)

    Štepán, J. Å.; Kašparová, J.; Karlický, M.; Heinzel, P.

    2007-09-01

    Aims:We investigate the effect of the electric return currents in solar flares on the profiles of hydrogen Balmer lines. We consider the monoenergetic approximation for the primary beam and runaway model of the neutralizing return current. Methods: Propagation of the 10 keV electron beam from a coronal reconnection site is considered for the semiempirical chromosphere model F1. We estimate the local number density of return current using two approximations for beam energy fluxes between 4 × 1011 and 1 × 1012 erg cm-2 s-1. Inelastic collisions of beam and return-current electrons with hydrogen are included according to their energy distributions, and the hydrogen Balmer line intensities are computed using an NLTE radiative transfer approach. Results: In comparison to traditional NLTE models of solar flares that neglect the return-current effects, we found a significant increase emission in the Balmer line cores due to nonthermal excitation by return current. Contrary to the model without return current, the line shapes are sensitive to a beam flux. It is the result of variation in the return-current energy that is close to the hydrogen excitation thresholds and the density of return-current electrons.

  12. Hydrogen Balmer-alpha broadening in dense plasmas.

    PubMed

    Alexiou, S; Leboucher-Dalimier, E

    1999-09-01

    This work presents a theoretical analysis of experimental results for the hydrogen Balmer-alpha line in dense plasmas, with electron densities between 2x10(18) and 9x10(18) e/cm(3) A simulation of both electrons and ions is employed to produce reliable theoretical widths. These results are essentially in agreement with standard theory results and, for the most part, disagree with the experimental results. Consequently, either mechanisms not accounted for in the theoretical results (such as quadrupoles) are more important than previously thought at these densities, or else there is a problem in the experimental data (such as a possible reabsorption, which is not ruled out by the experimental data). PMID:11970167

  13. Modelling of passive spectroscopy in the ITER divertor: the first hydrogen Balmer lines

    NASA Astrophysics Data System (ADS)

    Rosato, J.; Kotov, V.; Reiter, D.

    2010-07-01

    The first lines of the hydrogen Balmer series are investigated in ITER divertor conditions using a line shape code and a plasma edge transport code. It is shown that most of the emissivity originates from a localized, cold and dense region close to the divertor target plates, where the plasma is in the recombining regime. We simulate the signal obtained by pointing a spectrometer at this zone. The physical processes which contribute to the spectral line formation are examined, with a special emphasis on the Stark effect, photon absorption and stimulated emission. It is shown that, even though the Stark effect is significant, local information on the Doppler atomic temperature can be obtained from a fitting analysis of the Dα spectral line shape.

  14. Hydrogen Balmer Series Self-Absorption Measurement in Laser-Induced Air Plasma

    NASA Astrophysics Data System (ADS)

    Gautam, Ghaneshwar; Parigger, Christian

    2015-05-01

    In experimental studies of laser-induced plasma, we use focused Nd:YAG laser radiation to generate optical breakdown in laboratory air. A Czerny-Turner type spectrometer and an ICCD camera are utilized to record spatially and temporally resolved spectra. Time-resolved spectroscopy methods are employed to record plasma dynamics for various time delays in the range of 0.300 microsecond to typically 10 microsecond after plasma initiation. Early plasma emission spectra reveal hydrogen alpha and ionized nitrogen lines for time delays larger than 0.3 microsecond, the hydrogen beta line emerges from the free-electron background radiation later in the plasma decay for time delays in excess of 1 microsecond. The self-absorption analyses include comparisons of recorded data without and with the use of a doubling mirror. The extent of self-absorption of the hydrogen Balmer series is investigated for various time delays from plasma generation. There are indications of self-absorption of hydrogen alpha by comparison with ionized nitrogen lines at a time delay of 0.3 microsecond. For subsequent time delays, self-absorption effects on line-widths are hardly noticeable, despite the fact of the apparent line-shape distortions. Of interest are comparisons of inferred electron densities from hydrogen alpha and hydrogen beta lines as the plasma decays, including assessments of spatial variation of electron density.

  15. Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

    NASA Technical Reports Server (NTRS)

    Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.

    1987-01-01

    The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.

  16. Calculation of auroral Balmer volume emission height profiles in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Sigernes, F.; Lorentzen, D. A.; Deehr, C. S.; Henriksen, K.

    1994-03-01

    Energetic protons entering the atmosphere will either travel as auroral protons or as neutral hydrogen atoms due to charge-exchange and excitation interactions with atmospheric constituents. Our objective is to develop a simple procedure to evaluate the Balmer excitation rates of H(sub alpha) and H(sub beta) and produce the corresponding volume emission rates vs height, using semi-empirical range relations in air, starting from proton spectra observed from rockets above the main collision region as measured by REASONER et al. (1968) and Soraas et al. (1974). The main assumptions are that the geomagnetic field is parallel and vertical, and that the pitch angle of the proton/hydrogen atom is preserved in collisions with atmospheric constituents before being thermalized. Calculations show that the largest energy losses occur in the height interval between 100 and 125 km, and the corresponding volume emission rate vs height profiles have maximum values in this height interval. The calculated volume emission rate height profile of H(sub beta) compares favorably with that measured with a rocket-borne photometer.

  17. Variations of the ultraviolet Fe II and Balmer continuum emission in the Seyfert galaxy NGC 5548

    NASA Technical Reports Server (NTRS)

    Maoz, D.; Netzer, H.; Peterson, B. M.; Bechtold, J.; Bertram, R.; Bochkarev, N. G.; Carone, T. E.; Dietrich, M.; Filippenko, A. V.; Kollatschny, W.

    1993-01-01

    We present measurements of the Balmer continuum/Fe II emission blend between 2160 and 4130 A in the Seyfert galaxy NGC 5548. The measurements are from spectra obtained as part of the combined space-based and ground-based monitoring program of this object in 1988-1989. An iterative scheme is used to determine and subtract the continuum emission underlying the emission blend so as to obtain a light curve sampled once every four days. The small blue bump is an important component of the emission-line cooling, constituting about one third of the line flux in this object. Its flux varies with an amplitude of approximately +/- 20 percent about the mean, similar to the amplitude of the Balmer line variations during the same period. Its light curve resembles that of Ly-alpha, with a lag of about 10 days behind the continuum variations. The bump variation amplitude is independent of the wavelength interval where it is measured, which indicates that both the Balmer continuum and Fe II emission have comparable variation amplitudes. These results suggest that the Fe II UV multiplets and the Balmer continuum are emitted in the same parts of the broad-line region as most other broad emission lines in this object.

  18. Physical properties of Be star envelopes from Balmer and Fe II emission lines

    NASA Astrophysics Data System (ADS)

    Slettebak, Arne; Collins, George W., II; Truax, Ryland

    1992-07-01

    The study obtains H-alpha, B-beta, H-gamma, and Fe II 6516 line profiles with resolution 0.45 A for 41 bright Be stars with a CCD detonator during two observing periods in 1989. Analysis of the structure of the emission profiles indicates that the Be star emitting envelope is most likely axially symmetric, consistent with a rotating, equatorial disk. A number of Be stars show either a 'wine bottle' structure or inflection points on one side of their H-alpha emission profiles, suggesting a two-component structure for the emitting envelope: an inner disk, possibly turbulent, and an outer extended disk. Differentially rotating disks producing weak H-alpha emission are closer to the central star where rotation broadens the line more strongly, relative to stars with extended envelopes which emit strongly but rotate more slowly. From the Balmer emission decrements it is found that Be star envelopes with Te near 10,000 K have electron densities in the range 10 exp 11 to 10 exp 13/cu cm. Be stars with weak Balmer emission have, on average, somewhat flatter Balmer decrements than stars with strong emission, suggesting envelopes with higher electron densities.

  19. Inferring divertor plasma properties from hydrogen Balmer and Paschen series spectroscopy in JET-ILW

    NASA Astrophysics Data System (ADS)

    Lomanowski, B. A.; Meigs, A. G.; Sharples, R. M.; Stamp, M.; Guillemaut, C.; Contributors, JET

    2015-11-01

    A parametrised spectral line profile model is formulated to investigate the diagnostic scope for recovering plasma parameters from hydrogenic Balmer and Paschen series spectroscopy in the context of JET-ILW divertor plasmas. The separate treatment of Zeeman and Stark contributions in the line model is tested against the PPP-B code which accounts for their combined influence on the spectral line shape. The proposed simplified model does not fully reproduce the Stark-Zeeman features for the α and β transitions, but good agreement is observed in the line width and wing profiles, especially for n  >  5. The line model has been applied to infer radial density profiles in the JET-ILW divertor with generally good agreement between the D 5\\to 2 , 5\\to 3 , 6\\to 2 , 7\\to 2 and 9\\to 2 lines for high recycling and detached conditions. In an L-mode detached plasma pulse the Langmuir probe measurements typically underestimated the density by a factor 2-3 and overestimated the electron temperature by a factor of 5-10 compared to spectroscopically derived values. The line model is further used to generate synthetic high-resolution spectra for low-n transitions to assess the potential for parameter recovery using a multi-parametric fitting technique. In cases with 4 parameter fits with a single Maxwellian neutral temperature component the D 4\\to 3 line yields the best results with parameter estimates within 10% of the input values. For cases with 9 parameter fits inclusive of a multi-component neutral velocity distribution function the quality of the fits is degraded. Simultaneous fitting of the D 3\\to 2 and 4\\to 3 profiles improves the fit quality significantly, highlighting the importance of complementary spectroscopic measurements for divertor plasma emission studies.

  20. Hydrogen Balmer series measurements and determination of Rydberg's constant using two different spectrometers

    NASA Astrophysics Data System (ADS)

    Amrani, D.

    2014-07-01

    This paper investigates the use of two different methods, the optical and the computer-aided diffraction-grating spectrometer, to measure the wavelength of visible lines of Balmer series from the hydrogen atomic spectrum and estimate the value of Rydberg's constant. Analysis and interpretation of data showed that both methods, despite their difference in terms of the type of equipment used, displayed good performance in terms of precision of measurements of wavelengths of spectral lines. A comparison was carried out between the experimental value of Rydberg's constant obtained with both methods and the accepted value. The results of Rydberg's constant obtained with both the optical and computer-aided spectrometers were 1.099 28 × 10-7 m-1 and 1.095 13 × 10-7 m-1 with an error difference of 0.17% and 0.20% compared to the accepted value 1.097 373 × 10-7 m-1, respectively.

  1. Stimulated emission and the flat Balmer decrements of cataclysmic variable stars

    NASA Technical Reports Server (NTRS)

    Elitzur, M.; Ferland, G. J.; Mathews, S. G.; Shields, G. A.

    1983-01-01

    Balmer emission lines from cataclysmic variables often have nearly equal intensities rather than the rapid decrement predicted by simple nebular theory. Traditionally, this has been interpreted in terms of local thermodynamic equilibrium emission from a dense gas with small volume located just above the accretion disk. It is shown that the intense radiation field within a close binary system can affect excited state populations and optical emission in ways which allow a relatively low density gas to closely mimic the high density situation. In at least one case, the old nova V603 Aql, the emitting gas has a low density and nearly fills the orbital plane of the system. If this is characteristic of other systems, then the determination of orbital parameters and masses of cataclysmic variables from emission line radial velocities, as well as the prediction of soft X-ray emission from accreting binaries, will be affected.

  2. Evaluation of hydrogen atom density in the plasma core region based on the Balmer-α line profile

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    The Balmer-α line profile is measured with high wavelength resolution for a discharge in the Large Helical Device. The line profile is regarded as a superposition of continuously varying Doppler broadened components and is expressed as the Laplace transform. Numerical Laplace inversion of the measured line profile gives the distribution function of line emissivity in terms of atom temperature. The temperature dependence of the line emissivity is interpreted as spatial dependence so that the ionization rate and atom density of neutral hydrogen are determined. The temperature range of the detected atoms extends beyond 2 keV which corresponds to a penetration depth of about 1 m in the plasma, or the location at ρ ~ 0.3, where ρ is the normalized minor radius. The atom density of approximately 1013 m-3 is derived in the plasma core region which is more than four orders smaller than that at the plasma boundary. Calculation of neutral transport with a Monte-Carlo simulation code gives satisfactory consistency with the experimental results.

  3. Hydrogen Balmer α line behavior in Laser-Induced Breakdown Spectroscopy depth scans of Au, Cu, Mn, Pb targets in air

    NASA Astrophysics Data System (ADS)

    Senesi, G. S.; Benedetti, P. A.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.

    2010-07-01

    The behavior of hydrogen spectral emission of the plasmas obtained by Laser-Induced Breakdown Spectroscopy (LIBS) measurement of four metal targets (Au, Cu, Mn, Pb) in air was investigated. The plasma was produced by a pulsed Nd:YAG laser emitting in the fundamental wavelength. A systematic study of the spatial-integrated plasma emission obtained by an in-depth scanning of the target was performed for each metal, both in single pulse and collinear double-pulse configurations. Further, a spatial-resolved analysis of the emission of plasma produced on the Al target by a single laser pulse was performed, in order to describe the spatial distribution of emitters deriving from the target and air elements. The line intensities of the main plasma components (target metal, nitrogen, oxygen and hydrogen) were measured in both experimental conditions. Results show that the hydrogen line intensity varies greatly as a function of the metal considered, and exhibits a marked decrease after the first laser shots. However, differently from emission lines due to surface impurities, the hydrogen line intensity reaches a constant level deep inside the target. The spatial-resolved measurements indicate that hydrogen atoms in the plasma mainly derive from the target surface and, only at a minor extent, from the dissociation of molecular hydrogen present in the surrounding air. These findings show that the calculation of plasma electron number density through the measurement of the Stark broadening of hydrogen Balmer α line is possible also in depth scanning measurements.

  4. Black Hole Masses of Active Galaxies with Double-peaked Balmer Emission Lines

    NASA Astrophysics Data System (ADS)

    Lewis, Karen T.; Eracleous, Michael

    2006-05-01

    We have obtained near-IR spectra of five AGNs that exhibit double-peaked Balmer emission lines (NGC 1097, Pictor A, PKS 0921-213, 1E 0450.30-1817, and IRAS 0236.6-3101). The stellar velocity dispersions of the host galaxies were measured from the Ca II λλ8494, 8542, 8662 absorption lines and were found to range from 140 to 200 km s-1. Using the well-known correlation between the black hole mass and the stellar velocity dispersion, the black hole masses in these galaxies were estimated to range from 4×107 to 1.2×108 Msolar. We supplement the observations presented here with estimates of the black holes masses for five additional double-peaked emitters (Arp 102B, 3C 390.3, NGC 4579, NGC 4203, and M81) obtained by other authors using similar methods. Using these black hole masses, we infer the ratio of the bolometric luminosity to the Eddington luminosity, (Lbol/LEdd). We find that two objects (Pictor A and PKS 0921-213) have Lbol/LEdd~0.2, whereas the other objects have Lbol/LEdd<~10-2 (nearby, low-luminosity double-peaked emitters are the most extreme, with Lbol/LEdd<~10-4). The physical timescales in the outer regions of the accretion disks (at r~103GM/c2) in these objects were also estimated and range from a few months for the dynamical timescale to several decades for the sound crossing timescale. The profile variability in these objects is typically an order of magnitude longer than the dynamical time, but we note that variability occurring on the dynamical timescale has not been ruled out by the observations. Based on observations carried out at Cerro Tololo Inter-American Observatory, which is operated by AURA, Inc., under a cooperative agreement with the National Science Foundation.

  5. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, J.W.

    1993-03-30

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  6. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, J.W.

    1991-05-08

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using, a metal hydride.

  7. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, James W.

    1993-01-01

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  8. Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

    SciTech Connect

    Sisovic, N. M.; Konjevic, N.

    2008-11-15

    The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam{yields}NH{sub 3} experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

  9. Are Boltzmann plots of hydrogen Balmer lines a tool for identifying a subclass of S1 AGN?

    NASA Astrophysics Data System (ADS)

    Rafanelli, P.; Ciroi, S.; Cracco, V.; Di Mille, F.; Ilić, D.; La Mura, G.; Popović, L. Č.

    2014-10-01

    It is becoming clear that we can define two different types of nearby AGN belonging to the Seyfert 1 class (S1), on the basis of the match of the intensities of their Broad Balmer Lines (BBL) with the Boltzmann Plots (BP). These two types of S1 galaxies, that we call BP-S1 and NoBP-S1, are characterized, in first approximation, by Broad Line Regions (BLR) with different structural and physical properties. In this communication, we show that these features can be well pointed out by a multi-wavelength analysis of the continuum and of the broad recombination Hydrogen lines, that we carry out on a sample of objects detected at optical and X-ray frequencies. The investigation is addressed to verify whether BP-S1 are the ideal candidates for the study of the kinematical and structural properties of the BLR, in order to derive reliable estimates of the mass of their central engine and to constrain the properties of their nuclear continuum spectrum.

  10. Extended Pre-Transit Structures and the Exosphere Detected for HD189733b in Optical Hydrogen Balmer Line Absorption

    NASA Astrophysics Data System (ADS)

    Redfield, Seth; Cauley, P. Wilson; Jensen, Adam G.; Barman, Travis; Endl, Michael; Cochran, William

    2015-12-01

    We present two separate observations of HD189733b in the three strongest hydrogen Balmer lines (H-alpha, H-beta, and H-gamma), with HiRES on Keck I that show definitive in-transit absorption, confirming the detection with the HET by Jensen et al. (2012), as well as, significant pre-transit absorption. Recently, pre-transit absorption in UV metal transitions of the hot Jupiter exoplanets HD 189733b and WASP12-b have been interpreted as being caused by material compressed in a planetary bow shock, however our observations are the first to densely time-sample and redundantly detect these extended planetary structures. While our first observations (obtained in 2013 and presented in Cauley et al. 2015), were consistent with a bow shock, our subsequent observation taken in August 2015 show pre-transit absorption but with a pattern that is inconsistent with the 2013 model. Instead, the observations indicate significant variability in the strength and timing of the pre-transit absorption. We also find differences in the strength of the in-transit exospheric absorption as well. These changes could be indicative of variability in the extreme stellar wind properties found at just 8 stellar radii, which could drive the extended atmospheric interaction between star and planet. The pre-transit absorption in 2013 was first observed 65 minutes prior to transit (corresponding to a linear distance of ~7 planetary radii), although it could have started earlier. The pre-transit signal in 2015, which is well sampled, is first detected 165 minutes prior to transit (a linear distance of ~17 planetary radii). The line shape of the pre-transit feature and the shape of the time series absorption provide the strongest constraints on the morphology and physical characteristics of extended structures around the exoplanet. The absorption strength observed in the Balmer lines indicates an optically thick, but physically small, geometry. If part of this extended structure is a bow shock mediated

  11. EFFECTS OF AN ACCRETION DISK WIND ON THE PROFILE OF THE BALMER EMISSION LINES FROM ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Flohic, Helene M. L. G.; Eracleous, Michael; Bogdanovic, Tamara E-mail: mce@astro.psu.edu

    2012-07-10

    We explore the connection between active galactic nuclei (AGNs) with single- and double-peaked broad Balmer emission lines by using models dealing with radiative transfer effects through a disk wind. Our primary goal is to assess the applicability of the Murray and Chiang model by making an extensive and systematic comparison of the model predictions with data. In the process, we also verify the original derivation and evaluate the importance of general relativistic effects. As the optical depth through the emission layer increases, the peaks of a double-peaked profile move closer and eventually merge, producing a single peak. The properties of the emission line profile depend as sensitively on the geometric parameters of the line-emitting portion of the disk as they do on the disk-wind parameters. Using a parameter range that encompasses the expected characteristics of the broad-line regions in AGNs, we construct a database of model profiles and measure a set of diagnostic properties. Comparisons of the model profiles with emission lines from a subset of Sloan digital Sky Survey quasars show that observed lines are consistent with moderately large optical depth in the disk wind and a range of disk inclinations i {approx}< 45 Degree-Sign . Including relativistic effects is necessary to produce the asymmetries of observed line profiles.

  12. On Production Mechanisms For Balmer Line Radiation From 'Cold' Atomic Hydrogen and Deuterium In Fusion Edge Plasmas

    SciTech Connect

    Hey, John Douglas

    2010-10-29

    Published arguments, which assign dominant roles to atomic metastability and molecular ion dissociation in the production of 'narrow' Zeeman component Balmer line radiation from the tokamak edge plasma, have been examined critically in relation to: l-redistribution by proton collisions, molecular ion-proton equipartition, and ion acceleration by the plasma sheath (scrape-off layer) potential. These processes are found to constrain the contributions from metastable atoms and from dissociative excitation of molecular ions to 'narrow' Balmer spectra emitted from the plasma edge, in relation to the corresponding contributions from electron impact-induced dissociative excitation of neutral molecules.

  13. Asymmetry of the Balmer-alpha line shape and recovery of the effective hydrogen temperature in the tokamak scrape-off layer

    SciTech Connect

    Neverov, V. S. Kukushkin, A. B.; Lisgo, S. W. Kukushkin, A. S.; Alekseev, A. G.

    2015-02-15

    An algorithm for recovering the effective temperature of atoms of hydrogen (and its isotopes) in the tokamak scrape-off layer from the asymmetry of the Balmer-alpha line shape is proposed. The algorithm is based on the parametrization of the asymmetry of the line shape caused by the nonlocal character of neutral hydrogen flux from the wall into the tokamak plasma. The accuracy of the algorithm is tested against the results of simulations of the velocity distribution function of deuterium neutrals in the scrape-off layer by the EIRENE code with the use of the source data on the main plasma component in the quasi-stationary stage of the inductive mode of ITER operation calculated by the SOLPS4.3 (B2-EIRENE) code.

  14. Digital imaging technique for optical emission spectroscopy of a hydrogen arcjet plume

    NASA Astrophysics Data System (ADS)

    Litchford, Ron J.; Ruyten, Wim M.

    1995-07-01

    A digital imaging technique has been developed for optical emission spectroscopy measurements of a 1.6-kW hydrogen arcjet plume. Emissions from the Balmer alpha and beta transitions of excited atomic hydrogen were measured with a computer-controlled red-green-blue color CCD detector with and without line-centered bandpass interference filters. A method for extending the effective dynamic range of the detector was developed, whereby images obtained with a wide range of exposure times are combined to form a single composite nonsaturated map of the plume emission structure. The line-of-sight measurements were deconvoluted to obtain the true radial intensity distribution with an inverse Abel transformation. Analysis of the inverted measurements indicates that the upper levels of the Balmer alpha and beta transitions are not thermalized with the electrons in the plasma. The local thermodynamic equilibrium assumption fails for this plasma, and the electron temperature is not equivalent to the apparent excitation

  15. On the role of atomic metastability in the production of Balmer line radiation from ‘cold’ atomic hydrogen, deuterium and hydrogenic ion impurities in fusion edge plasmas

    NASA Astrophysics Data System (ADS)

    Hey, J. D.

    2012-03-01

    Published arguments, which assign an important role to atomic metastability in the production of ‘narrow’ Zeeman component radiation from the boundary region of fusion plasmas, are examined critically in relation to l-redistribution by proton and electron collisions, and mixing of unperturbed atomic states by the ion microfield and microfield gradient. It is concluded that these important processes indeed severely constrain the contribution from ‘metastable’ states to the generation of the hydrogen Balmer spectra, for electron concentrations above 1012 cm-3, as pointed out before by the present author (Hey et al 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3555). The analysis of collision-induced l-redistribution represents an extension of that used previously (Hey et al 1996 Contrib. Plasma Phys. 36 583), applicable up to higher electron densities. For comparison purposes, we also consider the question of metastability of ionized helium in a low-temperature plasma, and that of some common hydrogenic impurities (C5+ and Ne9+) in a hydrogen (deuterium) fusion plasma. While for low nuclear charge Z the metastability of 2s1/2 levels is quenched by the plasma environment, it is much reduced in high-Z ions owing to the rapid increase with Z of the two-photon electric dipole (2E1) and magnetic dipole (M1) spontaneous transition rates to the ground state, whereas the role of the plasma in these cases is less important. The main new principle elaborated in this work is the sensitivity of atomic line strengths, and hence collision strengths, to perturbation by the plasma environment for transitions between fine-structure sublevels of the same principal quantum number. As the plasma microfield strength grows, ‘allowed’ transitions diminish in strength, while ‘forbidden’ transitions grow. However, owing to violation of the parity selection rule, there is an overall loss of collision strength available to transitions, resulting from the appearance of significant

  16. Atmosphere Explorer observations of the geocoronal H Balmer alpha nightglow

    NASA Technical Reports Server (NTRS)

    Burrage, M. D.; Yee, J. H.; Abreu, V. J.

    1989-01-01

    The Balmer alpha nightglow emission of geocoronal atomic hydrogen has been investigated using photometric data obtained by the Visible Airglow Experiment on board the Atmosphere Explorer E satellite. The measured H Balmer alpha intensities are presented as a function of solar depression angle, observation zenith angle, and azimuth relative to the sun for solar minimum conditions. The results are at variance with the earlier D2A satellite observations but in better agreement with previous ground-based studies. As a result of comparison with theoretical predictions, the present observations reaffirm the findings of the ground-based investigations in implying that values for the Lyman beta line center flux are a factor of 2 greater than those derived from direct measurements.

  17. LS Pegasi: A Low-Inclination SW Sextantis-Type Cataclysmic Binary with High-Velocity Balmer Emission-Line Wings

    NASA Astrophysics Data System (ADS)

    Taylor, Cynthia J.; Thorstensen, John R.; Patterson, Joseph

    1999-02-01

    We present time-resolved spectroscopy and photometry of the bright cataclysmic variable LS Peg (=S193; V~13.0-Szkody et al.). The Balmer lines exhibit broad, asymmetric wings Doppler-shifted by about 2000 km s^-1 at the edges, while the He I lines show phase-dependent absorption features strikingly similar to SW Sextantis stars, as well as emission through most of the phase. The C III/N III emission blend does not show any phase dependence. From velocities of Hα emission lines, we determine an orbital period of 0.174774+/-0.000003 days (=4.1946 hr), which agrees with Szkody's value of approximately 4.2 hr. No stable photometric signal was found at the orbital period. A noncoherent quasi-periodic photometric signal was seen at a period of 20.7+/-0.3 minutes. The high-velocity Balmer wings most probably arise from a stream reimpact point close to the white dwarf. We present simulated spectra based on a kinematic model similar to the modified disk-overflow scenario of Hellier & Robinson. The models reproduce the broad line wings, though some other details are unexplained. Using an estimate of dynamical phase based on the model, we show that the phasing of the emission- and absorption-line variations is consistent with that in (eclipsing) SW Sex stars. We therefore identify LS Peg as a low-inclination SW Sex star. Our model suggests i=30^deg, and the observed absence of any photometric signal at the orbital frequency establishes i<60^deg. This constraint puts a severe strain on interpretations of the SW Sex phenomenon which rely on disk structures lying slightly out of the orbital plane.

  18. Broad Balmer-Line Absorption in SDSS J172341.10+555340.5

    NASA Astrophysics Data System (ADS)

    Aoki, Kentaro

    2010-10-01

    We present the discovery of Balmer-line absorption from Hα to H9 in an iron low-ionizaton broad absorption line (FeLoBAL) quasar, SDSS J172341.10+555340.5, by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) attached to the Subaru Telescope. The redshift of the Balmer-line absorption troughs is 2.0530±0.0003, and it is blueshifted by 5370 km s-1 from the Balmer emission lines. It is more than 4000 km s-1 blueshifted from the previously known UV absorption lines. We detected relatively strong (EWrest = 20 Å) [OIII] emission lines that are similar to those found in other broad absorption line quasars with Balmer-line absorption. We also derived the column density of neutral hydrogen of 5.2 × 1017 cm-2 by using the curve of growth and taking account of Lyα trapping. We searched for UV absorption lines that had the same redshift with Balmer-line absorption, and found Ali III and Fe III absorption lines at z = 2.053 that correspond to previously unidentified absorption lines, and the presence of other blended troughs that were difficult to identify.

  19. Shock-induced polarized hydrogen emission lines in omicron Ceti

    NASA Astrophysics Data System (ADS)

    Fabas, N.; Lèbre, A.; Gillet, D.

    2012-05-01

    Hydrogen emission lines in Mira variable stars are a well-known phenomenon whose origin has been established as related to the propagation of radiative hypersonic shock waves throughout the stellar atmosphere. A polarimetric observation by McLean and Coyne [1] made on omicron Ceti (the prototype of Mira variable stars) has revealed the existence of linear polarization signatures associated with Balmer emission lines. However, the polarizing mechanism has never been properly explained so far. The study presented here is the first of its kind since it displays the results of a spectropolarimetric survey of omicron Ceti in the Balmer lines. The survey was made with the NARVAL spectropolarimeter (Telescope Bernard Lyot, France) in full Stokes mode. We did not just confirm the appearance of this polarization but we also and above all showed the temporal variation of the linear polarization in the lines. We conclude that the polarizing mechanism is definitely intrinsic to the shock wave propagation throughout the stellar atmosphere of Mira and give some leads about the nature of this mechanism.

  20. The continuum emission spectrum of Hf 2-2 near the Balmer limit and the ORL versus CEL abundance and temperature discrepancy

    NASA Astrophysics Data System (ADS)

    Storey, P. J.; Sochi, Taha

    2014-05-01

    The continuum spectrum of the planetary nebula Hf 2-2 close to the Balmer discontinuity is modelled in the context of the long-standing problem of the abundance and temperature discrepancy found when analysing optical recombination lines and collisionally excited forbidden lines in nebulae. Models are constructed using single and double Maxwell-Boltzmann distributions as well as κ-distributions for the energies of the free electrons. New results for the necessary continuum and line emission coefficients are presented calculated with κ-distributed energies. The best fit to the observed continuum spectrum is found to be a model comprising two components with dramatically different temperatures and with a Maxwell-Boltzmann distribution of electron energies. On the basis of a χ2 analysis, this model is strongly favoured over a model with κ-distributed electron energies.

  1. Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device

    SciTech Connect

    Fujii, K.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2013-01-15

    We observe the Balmer-{alpha}, -{beta}, and -{gamma} lines of hydrogen atoms and Q branches of the Fulcher-{alpha} band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 {approx} 20 eV, while the rotational temperature of molecules is {approx}0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-{alpha} line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there.

  2. Digital imaging technique for optical emission spectroscopy of a hydrogen arcjet plume.

    PubMed

    Litchford, R J; Ruyten, W M

    1995-07-20

    A digital imaging technique has been developed for optical emission spectroscopy measurements of a 1.6-kW hydrogen arcjet plume. Emissions from the Balmer α and β transitions of excited atomic hydrogen were measured with a computer-controlled red-green-blue color CCD detector with and without line-centered bandpass interference filters. A method for extending the effective dynamic range of the detector was developed, whereby images obtained with a wide range of exposure times are combined to form a single composite nonsaturated map of the plume emission structure. The line-of-sight measurements were deconvoluted to obtain the true radial intensity distribution with an inverse Abel transformation. Analysis of the inverted measurements indicates that the upper levels of the Balmer α and β transitions are not thermalized with the electrons in the plasma. The local thermodynamic equilibrium assumption fails for this plasma, and the electron temperature is not equivalent to the apparent excitation temperature obtained when a Boltzmann energy distribution is assumed for the atomic hydrogen excited states. PMID:21052286

  3. Balmer decrements of T Tau stars

    NASA Astrophysics Data System (ADS)

    Katysheva, N. A.

    1981-04-01

    The relative intensities of Balmer lines calculated on the basis of Sobolev's probability method (1947) and the observed decrements of T Tau stars in the catalog of Cohen and Kuhi (1979) are compared with spectral classes between K5 and M5. For the group of stars, G5-K5, studied by Grinin (1980), emission was found to be predominantly of an envelope type, with less of a part played by chromospheric radiation. In K5-M5 stars, however, the envelope makes a smaller contribution to the total radiation, and most of the emission arises in the dense gas at the surface of the star. A comparison of the Balmer decrements of T Tau stars of different spectral classes and flare stars shows that in a transition to stars of lower luminosity, the role of chromospheric radiation increases.

  4. Theoretical quasar emission-line ratios. VII - Energy-balance models for finite hydrogen slabs

    NASA Technical Reports Server (NTRS)

    Hubbard, E. N.; Puetter, R. C.

    1985-01-01

    The present energy balance calculations for finite, isobaric, hydrogen-slab quasar emission line clouds incorporate probabilistic radiative transfer (RT) in all lines and bound-free continua of a five-level continuum model hydrogen atom. Attention is given to the line ratios, line formation regions, level populations and model applicability results obtained. H lines and a variety of other considerations suggest the possibility of emission line cloud densities in excess of 10 to the 10th/cu cm. Lyman-beta/Lyman-alpha line ratios that are in agreement with observed values are obtained by the models. The observed Lyman/Balmer ratios can be achieved with clouds whose column depths are about 10 to the 22nd/sq cm.

  5. Formation of broad Balmer wings in symbiotic stars

    NASA Astrophysics Data System (ADS)

    Chang, Seok-Jun; Heo, Jeong-Eun; Hong, Chae-Lin; Lee, Hee-Won

    2016-07-01

    Symbiotic stars are binary systems composed of a hot white dwarf and a mass losing giant. In addition to many prominent emission lines symbiotic stars exhibit Raman scattered O VI features at 6825 and 7088 Å. Another notable feature present in the spectra of many symbiotics is the broad wings around Balmer lines. Astrophysical mechanisms that can produce broad wings include Thomson scattering by free electrons and Raman scattering of Ly,β and higher series by neutral hydrogen. In this poster presentation we produce broad wings around Hα and H,β adopting a Monte Carlo techinique in order to make a quantitative comparison of these two mechanisms. Thomson wings are characterized by the exponential cutoff given by the termal width whereas the Raman wings are dependent on the column density and continuum shape in the far UV region. A brief discussion is provided.

  6. Segunda discontinuidad de Balmer y procesos físicos en envolturas extendidas de estrellas Be

    NASA Astrophysics Data System (ADS)

    Bibbo, I.; Cruzado, A.; Ringuelet, A.

    We study a group of Be stars in which the second Balmer jump is observed. Our aim is to correlate the second Balmer jump with other spectral features. Spectroscopic observations were performed with the 2.15 m telescope at Complejo Astronómico el Leoncito, CASLEO (San Juan, Argentina). In December 2001 and August 2002 high resolution echelle spectra were obtained with a REOSC echelle spectrograph. We find that, when a second Balmer jump in emission is observed, an emission in λ = 4233,17 Å of FeII multiplet 27 is also, generally seen. Besides, the electron temperature of the region of the envelope where the second jump is formed is estimated assuming that radiative recombinations cause the flux emission in the Balmer continuum. The temperature values obtained in this way are found correlated with the measure of the second Balmer jump.

  7. Shock-induced polarized hydrogen emission lines in the Mira star o Ceti

    NASA Astrophysics Data System (ADS)

    Fabas, N.; Lèbre, A.; Gillet, D.

    2011-11-01

    Context. In the spectra of variable pulsating stars, especially Mira stars, the detection of intense hydrogen emission lines has been explained by the presence of a radiative and hypersonic shock wave, periodically propagating throughout the stellar atmosphere. Previous observation of the Mira star o Ceti around one of its brightest maximum light led to the detection of a strong level of linear polarization associated to Balmer emissions, although the origin of this phenomenon is not fully explained yet. Aims: With the help of spectropolarimetry, we propose to investigate the nature of shock waves propagating throughout the stellar atmosphere and present, for o Ceti (the prototype of Mira stars), a full observational study of hydrogen emission lines formed in the radiative region of such a shock. Methods: Using the instrument NARVAL mounted on the Télescope Bernard Lyot (TBL) in Pic du Midi Observatory (France), we performed a spectropolarimetric monitoring of o Ceti during three consecutive pulsation cycles. For this survey, the four Stokes parameters (I for intensity, Q and U for linear polarization, and V for circular polarization) were systematically collected, with a particular emphasis on the maxima of luminosity, i.e. when a radiative shock wave is supposed to emerge from the photosphere and starts to propagate outward. Results: On hydrogen Balmer lines, over a large part of the luminosity cycle, we report clear detection of polarimetric structures in Q and U Stokes spectra (and also in V Stokes spectra but to a lesser extent). We report a temporal evolution of these spectropolarimetric signatures, which appear strongly correlated to the presence of an intense shock wave responsible for the hydrogen emission lines. We establish that the hydrogen lines are polarized by a physical process inherent to the mechanism responsible for the emission line formation: the shock wave itself. Two mechanisms are thus considered: a global one that implies a polarization

  8. Observations of a mode transition in a hydrogen hollow cathode discharge using phase resolved optical emission spectroscopy

    SciTech Connect

    Dixon, Sam Charles, Christine; Dedrick, James; Boswell, Rod; Gans, Timo; O'Connell, Deborah

    2014-07-07

    Two distinct operational modes are observed in a radio frequency (rf) low pressure hydrogen hollow cathode discharge. The mode transition is characterised by a change in total light emission and differing expansion structures. An intensified CCD camera is used to make phase resolved images of Balmer α emission from the discharge. The low emission mode is consistent with a typical γ discharge, and appears to be driven by secondary electrons ejected from the cathode surface. The bright mode displays characteristics common to an inductive discharge, including increased optical emission, power factor, and temperature of the H{sub 2} gas. The bright mode precipitates the formation of a stationary shock in the expansion, observed as a dark region adjacent to the source-chamber interface.

  9. Balmer line shifts in quasars

    NASA Astrophysics Data System (ADS)

    Sulentic, J. W.; Marziani, P.; Del Olmo, A.; Zamfir, S.

    2016-02-01

    We offer a broad review of Balmer line phenomenology in type 1 active galactic nuclei, briefly summarising luminosity and radio loudness effects, and discussing interpretation in terms of nebular physics along the 4D eigenvector 1 sequence of quasars. We stress that relatively rare, peculiar Balmer line profiles (i.e., with large shifts with respect to the rest frame or double and multiple peaked) that start attracted attentions since the 1970s are still passable of multiple dynamical interpretation. More mainstream objects are still not fully understood as well, since competing dynamical models and geometries are possible. Further progress may come from inter-line comparison across the 4D Eigenvector 1 sequence.

  10. Stationary Inverted Balmer and Lyman populations for a CW HI water-plasma laser

    NASA Astrophysics Data System (ADS)

    Mills, Randell L.

    2002-10-01

    Stationary inverted H Balmer and Lyman populations were observed from a low pressure water-vapor microwave discharge plasma. The ionization and population of excited atomic hydrogen levels was attributed to energy provided by a catalytic resonance energy transfer between hydrogen atoms and molecular oxygen formed in the water plasma. The catalysis mechanism was supported by the observation of O^2+ and H Balmer line broadening of 55 eV compared to 1 eV for hydrogen alone. The high hydrogen atom temperature with a relatively low electron temperature, Te = 2 eV, exhibited characteristics of cold recombining plasmas. These conditions of a water plasma favored an inverted population in the lower levels. Thus, the catalysis of atomic hydrogen may pump a cw HI laser. From our results, laser oscillations are may be possible from (i) n = 3, n = 4, n = 5, n = 6, n = 7, and n = 8 to n = 2, (ii) n = 4, n = 5, n = 6, and n = 7 to n = 3 and (iii) n = 5 and n = 6 to n = 4. Lines of the Balmer series of n = 5, and n = 6 to n = 2 and the Paschen series of n = 5 to n = 3 were of particular importance because of the potential to design blue and 1.3 micron infrared lasers, respectively, which are ideal for many communications and microelectronics applications. At a microwave input power of 9W/cm^3, a collisional radiative model showed that the hydrogen excited state population distribution was consistent with an n = 1arrow5,6 pumping power of an unprecedented 200W/cm^3. High power hydrogen gas lasers are anticipated at wavelengths, over a broad spectral range from far infrared to violet which may be miniaturized to micron dimensions. Such a hydrogen laser represents the first new atomic gas laser in over a decade, and it may prove to be the most efficient, versatile, and useful of all. A further application is the direct generation of electrical power using photovoltaic conversion of the spontaneous or stimulated water vapor plasma emission.

  11. Hydrogen/Air Fuel Nozzle Emissions Experiments

    NASA Technical Reports Server (NTRS)

    Smith, Timothy D.

    2001-01-01

    The use of hydrogen combustion for aircraft gas turbine engines provides significant opportunities to reduce harmful exhaust emissions. Hydrogen has many advantages (no CO2 production, high reaction rates, high heating value, and future availability), along with some disadvantages (high current cost of production and storage, high volume per BTU, and an unknown safety profile when in wide use). One of the primary reasons for switching to hydrogen is the elimination of CO2 emissions. Also, with hydrogen, design challenges such as fuel coking in the fuel nozzle and particulate emissions are no longer an issue. However, because it takes place at high temperatures, hydrogen-air combustion can still produce significant levels of NOx emissions. Much of the current research into conventional hydrocarbon-fueled aircraft gas turbine combustors is focused on NOx reduction methods. The Zero CO2 Emission Technology (ZCET) hydrogen combustion project will focus on meeting the Office of Aerospace Technology goal 2 within pillar one for Global Civil Aviation reducing the emissions of future aircraft by a factor of 3 within 10 years and by a factor of 5 within 25 years. Recent advances in hydrocarbon-based gas turbine combustion components have expanded the horizons for fuel nozzle development. Both new fluid designs and manufacturing technologies have led to the development of fuel nozzles that significantly reduce aircraft emissions. The goal of the ZCET program is to mesh the current technology of Lean Direct Injection and rocket injectors to provide quick mixing, low emissions, and high-performance fuel nozzle designs. An experimental program is planned to investigate the fuel nozzle concepts in a flametube test rig. Currently, a hydrogen system is being installed in cell 23 at NASA Glenn Research Center's Research Combustion Laboratory. Testing will be conducted on a variety of fuel nozzle concepts up to combustion pressures of 350 psia and inlet air temperatures of 1200 F

  12. Hydrogen emission in meteors as a potential marker for the exogenous delivery of organics and water

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Mandell, Avram M.

    2004-01-01

    We detected hydrogen Balmer-alpha (H(alpha)) emission in the spectra of bright meteors and investigated its potential use as a tracer for exogenous delivery of organic matter. We found that it is critical to observe the meteors with high enough spatial resolution to distinguish the 656.46 nm H(alpha) emission from the 657.46 nm intercombination line of neutral calcium, which was bright in the meteor afterglow. The H(alpha) line peak stayed in constant ratio to the atmospheric emissions of nitrogen during descent of the meteoroid. If all of the hydrogen originates in the Earth's atmosphere, the hydrogen atoms are expected to have been excited at T = 4400 K. In that case, we measured an H(2)O abundance in excess of 150 +/- 20 ppm at 80-90 km altitude (assuming local thermodynamic equilibrium in the air plasma). This compares with an expected <20 ppm from H(2)O in the gas phase. Alternatively, meteoric refractory organic matter (and water bound in meteoroid minerals) could have caused the observed H(alpha) emission, but only if the line is excited in a hot T approximately 10000 K plasma component that is unique to meteoric ablation vapor emissions such as Si(+). Assuming that the Si(+) lines of the Leonid spectrum would need the same hot excitation conditions, and a typical [H]/[C] = 1 in cometary refractory organics, we calculated an abundance ratio [C]/[Si] = 3.9 +/- 1.4 for the dust of comet 55P/Tempel-Tuttle. This range agreed with the value of [C]/[Si] = 4.4 measured for comet 1P/Halley dust. Unless there is 10 times more water vapor in the upper atmosphere than expected, we conclude that a significant fraction of the hydrogen atoms in the observed meteor plasma originated in the meteoroid.

  13. Hydrogen emission in meteors as a potential marker for the exogenous delivery of organics and water.

    PubMed

    Jenniskens, Peter; Mandell, Avram M

    2004-01-01

    We detected hydrogen Balmer-alpha (H(alpha)) emission in the spectra of bright meteors and investigated its potential use as a tracer for exogenous delivery of organic matter. We found that it is critical to observe the meteors with high enough spatial resolution to distinguish the 656.46 nm H(alpha) emission from the 657.46 nm intercombination line of neutral calcium, which was bright in the meteor afterglow. The H(alpha) line peak stayed in constant ratio to the atmospheric emissions of nitrogen during descent of the meteoroid. If all of the hydrogen originates in the Earth's atmosphere, the hydrogen atoms are expected to have been excited at T = 4400 K. In that case, we measured an H(2)O abundance in excess of 150 +/- 20 ppm at 80-90 km altitude (assuming local thermodynamic equilibrium in the air plasma). This compares with an expected <20 ppm from H(2)O in the gas phase. Alternatively, meteoric refractory organic matter (and water bound in meteoroid minerals) could have caused the observed H(alpha) emission, but only if the line is excited in a hot T approximately 10000 K plasma component that is unique to meteoric ablation vapor emissions such as Si(+). Assuming that the Si(+) lines of the Leonid spectrum would need the same hot excitation conditions, and a typical [H]/[C] = 1 in cometary refractory organics, we calculated an abundance ratio [C]/[Si] = 3.9 +/- 1.4 for the dust of comet 55P/Tempel-Tuttle. This range agreed with the value of [C]/[Si] = 4.4 measured for comet 1P/Halley dust. Unless there is 10 times more water vapor in the upper atmosphere than expected, we conclude that a significant fraction of the hydrogen atoms in the observed meteor plasma originated in the meteoroid. PMID:15104908

  14. Constraining sub-parsec binary supermassive black holes in quasars with multi-epoch spectroscopy. II. The population with kinematically offset broad Balmer emission lines

    SciTech Connect

    Liu, Xin; Shen, Yue; Bian, Fuyan; Loeb, Abraham; Tremaine, Scott

    2014-07-10

    A small fraction of quasars have long been known to show bulk velocity offsets (of a few hundred to thousands of km s{sup –1}) in the broad Balmer lines with respect to the systemic redshift of the host galaxy. Models to explain these offsets usually invoke broad-line region gas kinematics/asymmetry around single black holes (BHs), orbital motion of massive (∼sub-parsec (sub-pc)) binary black holes (BBHs), or recoil BHs, but single-epoch spectra are unable to distinguish between these scenarios. The line-of-sight (LOS) radial velocity (RV) shifts from long-term spectroscopic monitoring can be used to test the BBH hypothesis. We have selected a sample of 399 quasars with kinematically offset broad Hβ lines from the Sloan Digital Sky Survey (SDSS) Seventh Data Release quasar catalog, and have conducted second-epoch optical spectroscopy for 50 of them. Combined with the existing SDSS spectra, the new observations enable us to constrain the LOS RV shifts of broad Hβ lines with a rest-frame baseline of a few years to nearly a decade. While previous work focused on objects with extreme velocity offset (>10{sup 3} km s{sup –1}), we explore the parameter space with smaller (a few hundred km s{sup –1}) yet significant offsets (99.7% confidence). Using cross-correlation analysis, we detect significant (99% confidence) radial accelerations in the broad Hβ lines in 24 of the 50 objects, of ∼10-200 km s{sup –1} yr{sup –1} with a median measurement uncertainty of ∼10 km s{sup –1} yr{sup –1}, implying a high fraction of variability of the broad-line velocity on multi-year timescales. We suggest that 9 of the 24 detections are sub-pc BBH candidates, which show consistent velocity shifts independently measured from a second broad line (either Hα or Mg II) without significant changes in the broad-line profiles. Combining the results on the general quasar population studied in Paper I, we find a tentative anti-correlation between the velocity offset in the

  15. Hydrogen emissivity in realistic nebulae - The effects of velocity fields and internal dust

    NASA Astrophysics Data System (ADS)

    Cota, S. A.; Ferland, G. J.

    1988-03-01

    The paper presents calculations of the H-beta emissivity expected from nebulae with velocity gradients or internal dust. As has been found by Capriotti, Cox, and Mathews, Lyman line escape and destruction can prevent the 100 percent conversion of high-n Lyman lines into Ly-alpha and Balmer lines. For dusty environments such as the Orion Nebula or the general interstellar medium, the H-beta emissivity can be reduced by less than about 15 percent. Lyman line escape may cause still larger deviations in environments such as nova shells where the expansion velocities are large and velocity gradients likely. Although the partial conversion of Lyman lines only lowers the H-beta emissivity by typically less than about 10 percent under most circumstances, this introduces a systematic error in abundance measurements; the abundance of other elements relative to hydrogen will be overestimated by this amount. This effect must be considered in detail if very accurate abundance measurements are to be made. The present predictions of the deviation from case B emissivity are presented in a way in which they can be easily used by observers or incorporated into photoionization or shock codes.

  16. Development of multiwavelength-range fine-resolution spectrometer for hydrogen emissions and its application to large helical device periphery plasmas

    SciTech Connect

    Fujii, K.; Mizushiri, K.; Nishioka, T.; Shikama, T.; Hasuo, M.; Iwamae, A.; Goto, M.; Morita, S.; Kado, S; Sawada, K.

    2010-03-15

    We developed a spectrometer specialized for simultaneous observation of the hydrogen Balmer-{alpha}, -{beta}, -{gamma} lines and the Fulcher-{alpha} v'=v''=2 rovibronic transition band. The spectrometer was optimized for the light input coupled by nine optical fibers having 400 {mu}m core diameters. The spectral resolutions were 0.02-0.03 nm for these wavelength ranges at the entrance slit width of 20 {mu}m. The polarization resolved spectra of these emissions from the peripheral region of large helical device (LHD) plasmas were measured simultaneously and showed the polarization dependence coming from the magnetic field in the LHD plasma.

  17. Variability of Balmer Profiles in Magnetic Ap/Bp Stars

    NASA Astrophysics Data System (ADS)

    Valyavin, G.; Lee, B.-C.; Shulyak, D.; Han, I.; Kochukhov, O.; Khang, D.-I.; Kim, K.-M.

    2007-06-01

    A set of high precision measurements of weak variations of hydrogen lines in spectra of seven magnetic Ap/Bp stars was carried out using the BOES echelle spectrograph of the Bohuynsan Optical Astronomy Observatory (South Korea). A weak (1-2 %) periodic variability of the Balmer line wings has been detected in the spectra of 2 program stars. Upper limits of possible variations are presented for the remaining 5 objects. We discuss the discovered variability in the framework of model atmospheres with magnetic force terms included. The periodic changes in the Balmer profiles are caused by perturbations in atmospheres of Ap/Bp stars due to their rotationally modulated non-force-free magnetic fields.

  18. Balmer's Manuscripts and the Construction of His Series

    ERIC Educational Resources Information Center

    Banet, Leo

    1970-01-01

    Presents the results of an analysis of Balmer's draft manuscripts, which revealed new and pertinent details about the genesis of the Balmer series. In particular the origin and nature of Balmer's geometrical construction for the series is described. In addition, it is shown that the Balmer series played a direct role in the formulation of the…

  19. Data-model comparison search analysis of coincident PBO Balmer α, EURD Lyman β geocoronal measurements from March 2000

    NASA Astrophysics Data System (ADS)

    Bishop, J.; Mierkiewicz, E. J.; Roesler, F. L.; Gómez, J. F.; Morales, C.

    2004-05-01

    Recent Lyman series and Balmer series airglow measurements provide a fresh opportunity to investigate the density distribution and variability of atomic hydrogen in the upper atmosphere. Dedicated nightside Balmer α Fabry-Perot spectrometer measurements at the Pine Bluff Observatory (PBO), University of Wisconsin-Madison, have been acquired since late 1999 taking advantage of several technological advances. Extreme ultraviolet spectral radiance measurements by the Espectrógrafo Ultravioleta extremo para la Radiación Difusa (EURD) instrument on the Spanish MINISAT-1 satellite from October 1997 to December 2001 provide extensive sets of geocoronal Lyman β, Lyman γ and He 584 Å emission intensities. In this paper, coincident EURD Lyman β and PBO Balmer α radiance measurements from the early March 2000 new moon period are presented. In addition to serving as examples of the data sets now available, the data volume poses an analysis challenge not faced in prior geocoronal studies. A data-model comparison search procedure employing resonance radiation transport results for extensive sets of parametric density distribution models is being developed for use in analyses of multiple large data sets; this is described, and example results for the PBO and EURD March 2000 data sets are presented. The tightness of the constraints obtained for the solar line-center Lyman β irradiance and the atomic hydrogen column abundance is somewhat surprising, given the crudeness of the parameter binning in the search procedure and the fact that a small number of recognized corrections remain to be made to each data set.

  20. Hydrogen emissions from Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Moussallam, Yves; Oppenheimer, Clive; Aiuppa, Alessandro; Giudice, Gaetano; Moussallam, Manuel; Kyle, Philip

    2012-11-01

    The continuous measurement of molecular hydrogen (H2) emissions from passively degassing volcanoes has recently been made possible using a new generation of low-cost electrochemical sensors. We have used such sensors to measure H2, along with SO2, H2O and CO2, in the gas and aerosol plume emitted from the phonolite lava lake at Erebus volcano, Antarctica. The measurements were made at the crater rim between December 2010 and January 2011. Combined with measurements of the long-term SO2 emission rate for Erebus, they indicate a characteristic H2 flux of 0.03 kg s-1 (2.8 Mg day-1). The observed H2 content in the plume is consistent with previous estimates of redox conditions in the lava lake inferred from mineral compositions and the observed CO2/CO ratio in the gas plume (˜0.9 log units below the quartz-fayalite-magnetite buffer). These measurements suggest that H2 does not combust at the surface of the lake, and that H2 is kinetically inert in the gas/aerosol plume, retaining the signature of the high-temperature chemical equilibrium reached in the lava lake. We also observe a cyclical variation in the H2/SO2 ratio with a period of ˜10 min. These cycles correspond to oscillatory patterns of surface motion of the lava lake that have been interpreted as signs of a pulsatory magma supply at the top of the magmatic conduit.

  1. Hydrogen sensing characteristics from carbon nanotube field emissions.

    PubMed

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-14

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10(-9) Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing. PMID:26890686

  2. Hydrogen sensing characteristics from carbon nanotube field emissions

    NASA Astrophysics Data System (ADS)

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-01

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10-9 Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing.

  3. EMISSION CORRECTIONS FOR HYDROGEN FEATURES OF THE GRAVES ET AL. SLOAN DIGITAL SKY SURVEY AVERAGES OF EARLY-TYPE, NON-LINER GALAXIES

    SciTech Connect

    Serven, Jedidiah; Worthey, Guy E-mail: gworthey@wsu.ed

    2010-07-15

    For purposes of recovering correct absorption line strengths for stellar population analysis, emission corrections for Balmer series indices on the Lick index system in Sloan Digital Sky Survey (SDSS) stacked quiescent galaxy spectra are derived as a function of the Mg b index strength. These corrections are obtained by comparing the observed Lick index measurements of the SDSS composite spectra with new observed measurements of 13 Virgo Cluster galaxies, and checked with model grids. From the H{alpha}-Mg b diagram, a linear correction for the observed measurement is constructed using best-fit trend lines. Corrections for H{beta}, H{gamma}, and H{delta} are constructed using stellar population models to predict continuum shape changes as a function of Mg b plus Balmer series emission intensities typical of H II regions. The corrections themselves are fairly secure, but the interpretation for H{delta} and H{gamma} indices is complicated by the fact that the H{delta} and H{gamma} indices are sensitive to elemental abundances other than hydrogen.

  4. Nebular Hydrogen Absorption in the Ejecta of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Space Telescope Imaging Spectrograph (STIS) observations of Eta Carinae and immediate ejecta reveal narrow Balmer absorption lines in addition to the nebular-scattered broad P-Cygni absorptions. The narrow absorption correlates with apparent disk structure that separates the two Homunculus lobes. We trace these features about half way up the Northern lobe until the scattered stellar Balmer line doppler-shifts redward beyond the nebular absorption feature. Three-dimensional data cubes, made by mapping the Homunculus at Balmer alpha and Balmer beta with the 52 x 0.1 arcsecond aperture and about 5000 spectral resolving power, demonstrate that the absorption feature changes slowly in velocity with nebular position. We have monitored the stellar Balmer alpha line profile of the central source over the past four years. The equivalent width of the nebular absorption feature changes considerably between observations. The changes do not correlate with measured brightness of Eta Carinae. Likely clumps of neutral hydrogen with a scale size comparable to the stellar disk diameter are passing through the intervening light path on the timescales less than several months. The excitation mechanism involves Lyman alpha radiation (possibly the Lyman series plus Lyman continuum) and collisions leading to populating the 2S metastable state. Before the electron can jump to the ground state by two photon emission (lifetime about 1/8 second), a stellar Balmer photon is absorbed and the electron shifts to an NP level. We see the absorption feature in higher Balmer lines, and but not in Paschen lines. Indeed we see narrow nebular Paschen emission lines. At present, we do not completely understand the details of the absorption. Better understanding should lead to improved insight of the unique conditions around Eta Carinae that leads to these absorptions.

  5. Hydrogen line and continuum emission in young stellar objects. I - Excitation model

    NASA Technical Reports Server (NTRS)

    Kwan, John; Alonso-Costa, Jose L.

    1988-01-01

    Two mechanisms that populate the n = 2 level of hydrogen after the Lyman continuum is depleted are identified. They are ionization of N I from its excited states, followed by charge-exchange between N II and H I, and Ly-beta line wing absorption. Both processes involve absorption of the sub-Lyman continuum between 11 and 13.6 eV. With population in level n = 2 thus maintained, the strong Brackett line fluxes observed are then produced as a result of Balmer photoionization. The magnitude of the sub-Lyman continuum dictates the fraction of Balmer continuum that will be absorbed. Numerical calculations for four young stellar objects with luminosity ranging from 10 to 10,000 solar are performed, and it is concluded that this two-step process of sub-Lyman continuum absorption followed by Balmer photoionization can account for the great majority of observed Brackett line fluxes. The location and mass of the emitting as as determined from the Brackett line fluxes are reported. The Br-alpha luminosity is calculated as a function of the mass loss rate.

  6. Flare model sensitivity of the Balmer spectrum

    NASA Technical Reports Server (NTRS)

    Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.

    1989-01-01

    Careful studies of various chromospheric spectral signatures are very important in order to explore their possible sensitivity to the modifications of the thermodynamic quantities produced by the flare occurrence. Pioneer work of Canfield and co-workers have shown how the H alpha behavior is able to indicate different changes in the atmospheric parameters structure associated to the flare event. It was decided to study the behavior of the highest Balmer lines and of the Balmer continuum in different solar flare model atmospheres. These spectral features, originating in the deep photosphere in a quiet area, may have a sensitivity different from H alpha to the modification of a flare atmosphere. The details of the method used to compute the Stark profile of the higher Balmer line (n is greater than or equal to 6) and their merging were extensively given elsewhere (Donati-Falchi et al., 1985; Falchi et al., 1989). The models used were developed by Ricchiazzi in his thesis (1982) evaluating the chromospheric response to both the nonthermal electron flux, for energy greater than 20 kev, (F sub 20) and to the thermal conduction, (F sub c). The effect of the coronal pressure values (P sub O) at the apex of the flare loop is also included.

  7. Hydrogen emission in fatigue process of hydrogen-charged austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Hayashida, Katsuya; Matsunaga, Hisao; Endo, Masahiro

    2010-03-01

    The acceleration of hydrogen diffusion in the fatigue process of AISI type 304 and 316L meta-stable austenitic stainless steels was studied by paying attention to the relation between fatigue slip bands and hydrogen emission. Slip bands were formed in tension-compression fatigue tests of round specimens in ambient air, and then the specimens were cathodically charged with hydrogen. The location of hydrogen emission was microscopically visualized by means of the hydrogen microprint technique (HMT). Hydrogen was mainly emitted from slip bands on the surface of fatigued specimens. The depth of hydrogen diffusion into the specimens was also observed on the fatigue fracture surfaces by the HMT. The depth for a specimen hydrogen-charged before fatigue testing was about 50 μm at a maximum, whereas the depth for a specimen that was hydrogen-charged after slip bands had been formed in a preliminary fatigue test was about 300 μm. Those results suggested that slip bands act as a pathway where hydrogen will move preferentially.

  8. Hydrogen emission in fatigue process of hydrogen-charged austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Hayashida, Katsuya; Matsunaga, Hisao; Endo, Masahiro

    2009-12-01

    The acceleration of hydrogen diffusion in the fatigue process of AISI type 304 and 316L meta-stable austenitic stainless steels was studied by paying attention to the relation between fatigue slip bands and hydrogen emission. Slip bands were formed in tension-compression fatigue tests of round specimens in ambient air, and then the specimens were cathodically charged with hydrogen. The location of hydrogen emission was microscopically visualized by means of the hydrogen microprint technique (HMT). Hydrogen was mainly emitted from slip bands on the surface of fatigued specimens. The depth of hydrogen diffusion into the specimens was also observed on the fatigue fracture surfaces by the HMT. The depth for a specimen hydrogen-charged before fatigue testing was about 50 μm at a maximum, whereas the depth for a specimen that was hydrogen-charged after slip bands had been formed in a preliminary fatigue test was about 300 μm. Those results suggested that slip bands act as a pathway where hydrogen will move preferentially.

  9. The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge.

    PubMed

    Cortázar, O D; Megía-Macías, A; Tarvainen, O; Kalvas, T; Koivisto, H

    2015-08-01

    The relationship between Balmer-α and Fulcher-band emissions with extracted H(+), H2(+), and H3(+) ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical view-port on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed. PMID:26329183

  10. The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Megía-Macías, A.; Tarvainen, O.; Kalvas, T.; Koivisto, H.

    2015-08-01

    The relationship between Balmer-α and Fulcher-band emissions with extracted H+, H2 + , and H3 + ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical view-port on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed.

  11. Detection of Broad Hα Emission Lines in the Late-time Spectra of a Hydrogen-poor Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Yan, Lin; Quimby, R.; Ofek, E.; Gal-Yam, A.; Mazzali, P.; Perley, D.; Vreeswijk, P. M.; Leloudas, G.; De Cia, A.; Masci, F.; Cenko, S. B.; Cao, Y.; Kulkarni, S. R.; Nugent, P. E.; Rebbapragada, Umaa D.; Woźniak, P. R.; Yaron, O.

    2015-12-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83-148 days to reach a peak bolometric luminosity of ˜1.3 × 1044 erg s-1, then decays slowly at 0.015 mag day-1. The measured ejecta velocity is ˜ 13,000 km s-1. The inferred explosion characteristics, such as the ejecta mass (70-220 M⊙), and the total radiative and kinetic energy (Erad ˜ 1051 erg, Ekin ˜ 2 × 1053 erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmeremission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ˜4500 km s-1 and a ˜300 km s-1 blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ˜2 × 1041 erg s-1 as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ˜4 × 1016 cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M⊙. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M⊙ H-shell, ejected from a progenitor star with an initial mass of (95-150) M⊙ about 40 years ago. We estimate that at least ˜15% of all SLSNe-I may have late-time Balmer emission lines.

  12. Balmer-α spectrum measurements of the LHD one-third ion source

    NASA Astrophysics Data System (ADS)

    Wada, M.; Kenmotsu, T.; Kisaki, M.; Nakano, H.; Nishiura, M.; Tsumori, K.

    2016-02-01

    Wavelength spectra of Balmer-α light from plasmas in the extraction region of the Large Helical Device-R&D negative ion source, or the LHD one-third ion source have exhibited a blue shift as a negative bias voltage was applied to the plasma grid. The blue shift increased as the negative bias voltage with respect to the local plasma potential was increased. The measured spectra were compared with the velocity distributions of surface reflected hydrogen atoms calculated by atomic collisions in amorphous target code. The arc power and the source H2 pressure also affected the shift and broadening in the observed Balmer-α spectra. The possibility of identifying the negative hydrogen ions produced at the low work function plasma grid surface by high resolution spectroscopy is discussed.

  13. Balmer-α spectrum measurements of the LHD one-third ion source.

    PubMed

    Wada, M; Kenmotsu, T; Kisaki, M; Nakano, H; Nishiura, M; Tsumori, K

    2016-02-01

    Wavelength spectra of Balmer-α light from plasmas in the extraction region of the Large Helical Device-R&D negative ion source, or the LHD one-third ion source have exhibited a blue shift as a negative bias voltage was applied to the plasma grid. The blue shift increased as the negative bias voltage with respect to the local plasma potential was increased. The measured spectra were compared with the velocity distributions of surface reflected hydrogen atoms calculated by atomic collisions in amorphous target code. The arc power and the source H2 pressure also affected the shift and broadening in the observed Balmer-α spectra. The possibility of identifying the negative hydrogen ions produced at the low work function plasma grid surface by high resolution spectroscopy is discussed. PMID:26931989

  14. 40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Emission Limits for Hydrogen Halide and... to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP... following table that applies to your process vents that contain hydrogen halide and halogen HAP emissions...

  15. 40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Hydrogen Halide and... to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP... following table that applies to your process vents that contain hydrogen halide and halogen HAP emissions...

  16. Secondary-electron emission from hydrogen-terminated diamond

    SciTech Connect

    Wang E.; Ben-Zvi, I.; Rao, T.; Wu, Q.; Dimitrov, D.A.; T. Xin, T.

    2012-05-20

    Diamond amplifiers demonstrably are an electron source with the potential to support high-brightness, high-average-current emission into a vacuum. We recently developed a reliable hydrogenation procedure for the diamond amplifier. The systematic study of hydrogenation resulted in the reproducible fabrication of high gain diamond amplifier. Furthermore, we measured the emission probability of diamond amplifier as a function of the external field and modelled the process with resulting changes in the vacuum level due to the Schottky effect. We demonstrated that the decrease in the secondary electrons average emission gain was a function of the pulse width and related this to the trapping of electrons by the effective NEA surface. The findings from the model agree well with our experimental measurements. As an application of the model, the energy spread of secondary electrons inside the diamond was estimated from the measured emission.

  17. Hydrogen enrichment for low-emission jet combustion

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1978-01-01

    Simultaneous gaseous pollutant emission indexes (g pollutant/kg fuel) for a research combustor with inlet air at 120,900 N/sq m (11.9 atm) pressure and 727 K (849 F) temperature are as low as 1.0 for NOx and CO and 0.5 for unburned HC. Emissions data are presented for hydrogen/jet fuel (JP-5) mixes and for jet fuel only for premixed equivalence ratios from lean blowout to 0.65. Minimized emissions were achieved at an equivalence ratio of 0.38 using 10-12 mass percent hydrogen in the total fuel to depress the lean blowout limit. They were not achievable with jet fuel alone because of the onset of lean blowout at an equivalence ratio too high to reduce the NOx emission sufficiently.

  18. Spatial imaging of hydrogen Lyman-alpha emission from Jupiter

    NASA Technical Reports Server (NTRS)

    Clarke, J. T.; Weaver, H. A.; Feldman, P. D.; Moos, H. W.; Fastie, W. G.; Opal, C. B.

    1980-01-01

    A sounding rocket measurement of the H I L-alpha emission from Jupiter made on Dec. 1, 1978 shows limb darkening and an average disk brightness of 13 kR. This brightness is significantly higher than in previous measurements, and was confirmed by an IUE observation on Dec. 10, 1978. Comparison with a plane-parallel hydrogen layer model indicates that there is enhanced emission from the equatorial regions, reaching a peak near 80 deg longitude.

  19. Hybrid and conventional hydrogen engine vehicles that meet EZEV emissions

    SciTech Connect

    Aceves, S.M.; Smith, J.R.

    1996-12-10

    In this paper, a time-dependent engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many experimental points obtained in a recent evaluation of a hydrogen research engine. A The validated engine model is then used to calculate fuel economy and emissions for three hydrogen-fueled vehicles: a conventional, a parallel hybrid, and a series hybrid. All vehicles use liquid hydrogen as a fuel. The hybrid vehicles use a flywheel for energy storage. Comparable ultra capacitor or battery energy storage performance would give similar results. This paper analyzes the engine and flywheel sizing requirements for obtaining a desired level of performance. The results indicate that hydrogen lean-burn spark-ignited engines can provide a high fuel economy and Equivalent Zero Emission Vehicle (EZEV) levels in the three vehicle configurations being analyzed.

  20. Molecular hydrogen emission from W51

    NASA Technical Reports Server (NTRS)

    Beckwith, S.; Zuckerman, B.

    1981-01-01

    The detection of emission from the v = 1 approaches 0 S(1) quadrupole transition of H2 toward the cluster of intense infrared and H2O maser sources in W51 (north) is reported. The apparent luminosity of this line in W51 (north) is only about 4% of the luminosity of the same line toward the Kleinmann-Low infrared cluster in Orion; however, additional line-of-sight extinction and spatial extent of the source may account for the lower apparent power in W51. Similarity in the infrared and H2O properties of these clusters is addressed. The implications of the H2 emission for mass loss in the W51 region is discussed and some proposed models of radiation-driven mass outflow from pre-main sequence stars are briefly considered.

  1. Analysis of experimental hydrogen engine data and hydrogen vehicle performance and emissions simulation

    SciTech Connect

    Aceves, S.A.

    1996-10-01

    This paper reports the engine and vehicle simulation and analysis done at Lawrence Livermore (LLNL) as a part of a joint optimized hydrogen engine development effort. Project participants are: Sandia National Laboratory; Los Alamos National Laboratory; and the University of Miami. Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios. NO{sub x} emissions can be reduced to less than 10 ppm without catalyst. HC and CO emissions may result from oxidation of engine oil, but by proper design are negligible (a few ppm). Lean operation also results in increased indicated efficiency due to the thermodynamic properties of the gaseous mixture contained in the cylinder. The high effective octane number of hydrogen allows the use of a high compression ratio, further increasing engine efficiency. In this paper, a simplified engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many experimental points obtained in a recent evaluation of a hydrogen research engine. The experimental data are used to adjust the empirical constants in the heat release rate and heat transfer correlation. The results indicate that hydrogen lean-burn spark-ignite engines can provide Equivalent Zero Emission Vehicle (EZEV) levels in either a series hybrid or a conventional automobile.

  2. Recombination and collisionally excited Balmer lines

    NASA Astrophysics Data System (ADS)

    Raga, A. C.; Castellanos-Ramírez, A.; Esquivel, A.; Rodríguez-González, A.; Velázquez, P. F.

    2015-10-01

    We present a model for the statistical equilibrium of the levels of H, considering recombinations to excited levels, collisional excitations up from the ground state and spontaneous radiative transitions. This problem has a simple "cascade matrix" solution, describing a cascade of downwards spontaneous transitions fed by both recombinations and collisional excitations. The resulting predicted Balmer line ratios show a transition between a low temperature and a high temperature regime (dominated by recombinations and by collisional excitations, respectively), both with only a weak line ratio vs. temperature dependence. This clear characteristic allows a direct observational identification of regions in which the Balmer lines are either recombination or collisionally excited transitions. We find that for a gas in coronal ionization equilibrium the Halpha and Hbeta lines are collisionally excited for all temperatures. In order to have recombination Halpha and Hbeta it is necessary to have higher ionization fractions of H than the ones obtained from coronal equilibrium (e.g., such as the ones found in a photoionized gas).

  3. Hydrogen emission under laser exposure of colloidal solutions of nanoparticles

    NASA Astrophysics Data System (ADS)

    Barmina, E. V.; Simakin, A. V.; Shafeev, G. A.

    2016-07-01

    We report the generation of molecular hydrogen from water by laser irradiation, without any electrodes and photocatalysts. A near infrared pulsed nanosecond laser is used for exposure of colloidal solution of Au nanoparticles suspended in water. Laser exposure of the colloidal solution results in formation of breakdown plasma in liquid and emission of H2. The rate of H2 emission depends critically on the energy of laser pulses. There is a certain threshold in laser fluence in liquid (around 50 J/cm2) below which plasma disappears and H2 emission stops. H2 emission from colloidal solution of Au nanoparticles in ethanol is higher than that from similar water colloid. It is found that formation of plasma and emission of H2 or D2 can be induced by laser exposure of pure liquids, either H2O or D2O, respectively. The results are interpreted as water molecules splitting by direct electron impact from breakdown plasma.

  4. Molecular Hydrogen Line Emission from Photodissociation Regions

    NASA Astrophysics Data System (ADS)

    Chrysostomou, Antonio

    1993-01-01

    The work presented in this thesis is dedicated to the study of the physical properties of photodissociation regions (PDRs), the surface layers of molecular clouds which are irradiated by ultraviolet radiation. The structure of PDRs is investigated with the development of an anlytical model which incorporates the essential heating and cooling mechanisms in a PDR. The main parameters in the model are the density and the incident ulttraviolet radiation field (G0) impinging on the surface which dissociates the molecules in the PDR. It is demonstrated that when the ratio (n / G0) is high (> 100 cm-3) the attenuation of ultraviolet photons is dominated by H2 self shielding, which brings the Hi/H2 transition zone close to the surface of the cloud (Av < 1). When the ratio is of order unity then the attenuation of ultraviolet photons is dominated by dust grains in the PDR. In this case, the Hi / H2 transition zone occurs at a depth of Av ~2-3. Images of the PDR in the northern bar of M17 show that there is a spatial coincidence, accurate to ~1 arcsec, of the H2 and 3.28 micron emission regions (the 3.28 micron emission being a tracer of the hot edge of the PDR delineated by the Hii / Hi transition) placing a lower limit to the density in the clumps of 105 cm-3. This coincidence is also observed in other PDR sources (eg. NGC 2023) and can be readily explained if the sources are clumpy. It is not clear in the northern bar of M17, where G0 ~104, whether shielding by dust or H2 molecules is dominated the attenuation of ultraviolet photons. A uniform, high density PDR model is sufficient to reproduce the observed H2 line intensity, however the images clearly reveal structures at the 2 arcsec level suggesting that a clumpy model is a realistic solution. Long slit K band spectroscopy measurements were taken in the northern bar of M17, where up to 16 H2 lines were identified. Analysis of the data suggests that the emission can only be explained if the H2 molecules are being excited

  5. EMISSIONS REDUCTIONS USING HYDROGEN FROM PLASMATRON FUEL CONVERTERS

    SciTech Connect

    Bromberg, L

    2000-08-20

    Substantial progress in engine emission control is needed in order to meet present and proposed regulations for both spark ignition and diesel engines. Tightening regulations throughout the world reflect the ongoing concern with vehicle emissions. Recently developed compact plasmatron fuel converters have features that are suitable for onboard production of hydrogen for both fuel pretreatment and for exhaust aftertreatment applications. Systems that make use of these devices in conjunction with aftertreatment catalysts have the potential to improve significantly prospects for reduction of diesel engine emissions. Plasmatron fuel converters can provide a rapid response compact means to transform efficiently a wide range of hydrocarbon fuels into hydrogen rich gas. They have been used to reform natural gas [Bromberg1], gasoline [Green], diesel [Bromberg2] and hard-to-reform biofuels [Cohn1] into hydrogen rich gas (H2 + CO). The development of these devices has been pursued for the purpose of reducing engine exhaust pollutants by providing hydrogen rich gas for combustion in spark ignition and possibly diesel engines, as shown in Figure 1 [Cohn2]. Recent developments in compact plasmatron reformer design at MIT have resulted in substantial decreases in electrical power requirements. These new developments also increase the lifetime of the electrodes.

  6. Direct hydrogen production from alcohol using pulse-electron emission in an unsymmetrical electric field

    NASA Astrophysics Data System (ADS)

    Matsuura, H.; Tanikawa, T.; Takaba, H.; Fujiwara, Y.

    2004-05-01

    We report a means of instantaneously producing hydrogen directly from alcohol using pulse-electron emission in an unsymmetrical electric field. We selected 1-butanol as a hydrogen-rich material for producing hydrogen. A 1-butanol molecule has more than twice as many hydrogen atoms as the methanol molecule and is a good candidate for a hydrogen source. The direct electron emission on the surface of volatile 1-butanol prevented intense discharge and produced hydrogen at room temperature in air.

  7. Hydrogen cyanide exhaust emissions from in-use motor vehicles.

    PubMed

    Baum, Marc M; Moss, John A; Pastel, Stephen H; Poskrebyshev, Gregory A

    2007-02-01

    Motor vehicle exhaust emissions are known to contain hydrogen cyanide (HCN), but emission rate data are scarce and, in the case of idling vehicles, date back over 20 years. For the first time, vehicular HCN exhaust emissions from a modern, in-use fleet at idle have been measured. The 14 tested light duty motor vehicles were operating at idle as these conditions are associated with the highest risk exposure scenarios (i.e., enclosed spaces). Vehicular HCN was detected in 89% of the sampled exhaust streams and did not correlate with instantaneous air-fuel-ratio or with any single, coemitted pollutant. However, a moderate correlation between HCN emissions and the product of carbon monoxide and nitric oxide emissions was observed under cold-start conditions. Fleet average, cold-start, undiluted HCN emissions were 105 +/- 97 ppbV (maximum: 278 ppbV), whereas corresponding emissions from vehicles operating under stabilized conditions were 79 +/- 71 ppbV (maximum: 245 ppbV); mean idle fleet HCN emission rates were 39 +/- 35 and 21 +/- 18 microg-min(-1) for cold-start and stabilized vehicles, respectively. The significance of these results is discussed in terms of HCN emissions inventories in the South Coast Air Basin of California and of health risks due to exposure to vehicular HCN. PMID:17328194

  8. 40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Emission Limits for Hydrogen Halide and..., Table 3 Table 3 to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP Emissions... limit in the following table that applies to your process vents that contain hydrogen halide and...

  9. Measurement and Simulation of Deuterium Balmer-Alpha Emission from First-Orbit Fast Ions and the Application to Neutral Density and General Fast-Ion Loss Detection in the DIII-D Tokamak

    NASA Astrophysics Data System (ADS)

    Bolte, Nathan Glynn

    Spectra of the Balmer-alpha radiation of first-orbit fast ions after charge exchange with edge neutrals have been measured in the DIII-D tokamak. Several collimated optics systems view the edge region---while avoiding any active beams---and carry light to a spectrometer tuned to the region of the 656.1 nm deuterium-alpha line. Viewing geometry and the high energy of the lost ions produce Doppler shifts, which effectively separate the fast-ion contributions from the bright, cold edge light. Modulation of the fast-ion source allows for time-evolving background subtraction. A model has been developed for the spectra of these first-orbit fast ions. The passive fast-ion D-alpha simulation (P-FIDAsim) is a forward model consisting of an experimentally- validated beam model, an ion orbit-following code, a collisional-radiative model, and a synthetic spectrometer. Eighty-six experimental spectra were obtained using 6 different neutral beam fast-ion sources and 13 different viewing chords. Parameters such as plasma current, toroidal field, electron density, plasma cross-sectional shape, and number of x-points were varied. Uncalibrated experimental spectra have an overall Spearman rank correlation coefficient with the shape of simulated spectra of 0.58 with subsets of cases rising to a correlation of 0.80. A single set of calibrated spectra (shot 152817) was measured and is used to estimate the neutral density throughout the cross-section of the tokamak. This is done by inverting the simulated spectra in order to find the best neutral density (in a least squares sense) required to best match the experimental spectra. The resulting 2D neutral density shows the expected increase toward each x-point. The average neutral density is found to be 3.3 x 105cm -3 a the magnetic axis, 2.3 x 108cm -3 in the core, 8.1 x 109 cm-3 at the plasma boundary, and 1.1 x 10 11cm-3 near the wall. A technique is developed which--after us first-orbit light to calibrate the system--can quantify

  10. The Transition Zone in Balmer-dominated Shocks

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; van Adelsberg, Matthew; McCray, Richard; Raymond, John C.

    2007-10-01

    We examine the structure of the postshock region in supernova remnants (SNRs). The ``shock transition zone'' is set up by charge transfer and ionization events between atoms and ions and has a width ~(1015 cm-2)n-10, where n0 is the total preshock density (including both atoms and ions). For Balmer-dominated SNRs with shock velocity vs>~1000 km s-1, the Rankine-Hugoniot conditions for ion velocity and temperature are obeyed instantly, leaving the full width at half-maximum (FWHM) of the broad Hα line versus vs relation intact. However, the spatial variation in the postshock densities is relevant to the problem of Lyα resonant scattering in young, core-collapse SNRs. Both two- (preshock atoms and ions) and three-component (preshock atoms, broad neutrals, and ions) models are considered. We compute the spatial emissivities of the broad (ξb) and narrow (ξn) Hα lines; a calculation of these emissivities in SN 1006 is in general agreement with the computed ones of Raymond and coworkers. The (dimensionless) spatial shift, Θshift, between the centroids of ξb and ξn is unique for a given shock velocity and fion, the preshock ion fraction. Measurements of Θshift can be used to constrain n0.

  11. Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Markarian 6

    NASA Astrophysics Data System (ADS)

    Asatrian, Norayr S.

    2014-07-01

    Part of results of the multi-epoch intranight optical spectroscopic monitoring of the Markarian 6 nucleus carried out at the telescopes of 6-m of the Special Astrophysical Observatory (Russia), 2.6-m of the Byurakan Astrophysical Observatory (Armenia) and 2-m of the Tautenburg Observatory (Germany) is presented. Observations were made in 1979, 1986, 1988-1991 and 2007-2009 during a total of 33 nights with an average sampling rate of 4 spectra per night. TV-scanner and long-slit spectrographs equipped with Image Tube and CCD detector arrays were used. Altogether we analyzed 110 Hβ and 58 Hα region spectra to search for intranight variability in the broad hydrogen emission line profiles. The typical spectral resolutions were 4 Å for scanner spectra, 6 Å for photographic spectra, and 5 Å and 10 Å for CCD spectra. The S/N ratio at the continuum level near the Hβ and Hα lines was in the range 15-50. The purpose of the search was to look for the characteristic variability signatures of different kinematical models of the broad emission-line region. We considered the centering and guiding errors which can result in differences between spectra. We found variations in the broad Balmer line difference profiles on time scale of hour with the level of significance of 3.6 σ to 5.0 σ. Variations take the form of narrow, small bumps located at the blue and red sides or only at the blue side of the lines. In the intermediate level of broad line flux, the Hβ and Hα profiles show fine structure. Detected profile changes occurred at the same radial velocity shifts as the details in the fine structure. The variability is at least 2 orders of magnitude more rapid than any observed for broad Balmer line profiles in AGNs that we are aware of in the literature. Discovered extremely rapid line-profile variability may be associated with reverberation effects. Two-sided profile changes may indicate the response of circularly rotating hydrogen clouds in the BLR to a light pulse

  12. Influence of cathode material on generation of energetic hydrogen atoms in a glow discharge

    SciTech Connect

    Cvetanovic, N.; Obradovic, B. M.; Kuraica, M. M.

    2011-01-01

    In this paper influence of cathode material on formation of fast hydrogen atoms in an abnormal glow discharge is investigated using Balmer alpha emission spectroscopy. Energetic H atoms are generated in charge exchange reactions of hydrogen ions that are accelerated in the electric field, and also formed in the backscattering process at the cathode surface. Copper and graphite cathodes were used. Investigation was performed in two orthogonal directions of observation in pure hydrogen and argon-hydrogen mixture. The shapes of the profiles are examined together with the space intensity distribution of Balmer alpha line. Reduced atom reflection from graphite was manifested in the spectroscopic result, in accordance to the field acceleration model. The effect was evident only at high ion energies. This is explained by energy dependence of reflection coefficient for H atoms.

  13. A Possible Solution to the Lyman/Balmer Line Problem in Hot DA White Dwarfs

    NASA Astrophysics Data System (ADS)

    Preval, Simon P.; Barstow, Martin A.; Badnell, Nigel R.; Holberg, Jay B.; Hubeny, Ivan

    2015-06-01

    Arguably, the best method for determining the effective temperature (Teff) and surface gravity (log g) of a DA white dwarf is by fitting the Hydrogen Lyman and Balmer absorption features. However, as has been shown for white dwarfs with Teff>50,000K, the calculated value from the Lyman and Balmer lines are discrepant, which worsens with increasing temperature. Many different solutions have been suggested, ranging from the input physics used to calculate the models, to interstellar reddening. We will focus on the former, and consider three variables. The first is the atomic data used, namely the number of transitions included in line blanketing treatments and the photoionization cross sections. The second is the stark broadening treatment used to synthesise the Lyman and Balmer line profiles, namely the calculations performed by Lemke (1997) and Tremblay & Bergeron (2009). Finally, the third is the atmospheric content. The model grids are calculated with a pure H composition, and a metal polluted composition using the abundances of Preval et al. (2013). We present the preliminary results of our analysis, whereby we have determined the Teff for a small selection of white dwarfs. We plan to extend our analysis by allowing metallicity to vary in future model grids.

  14. 40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Emission Limits for Hydrogen Halide.... FFFF, Table 3 Table 3 to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP... limit in the following table that applies to your process vents that contain hydrogen halide and...

  15. 40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Emission Limits for Hydrogen Halide.... FFFF, Table 3 Table 3 to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP... limit in the following table that applies to your process vents that contain hydrogen halide and...

  16. Optical emission spectroscopy of argon and hydrogen-containing plasmas

    NASA Astrophysics Data System (ADS)

    Siepa, Sarah; Danko, Stephan; Tsankov, Tsanko V.; Mussenbrock, Thomas; Czarnetzki, Uwe

    2015-09-01

    Optical emission spectroscopy (OES) on neutral argon is applied to investigate argon, hydrogen and hydrogen-silane plasmas. The spectra are analyzed using an extensive collisional-radiative model (CRM), from which the electron density and the electron temperature (or mean energy) can be calculated. The CRM also yields insight into the importance of different excited species and kinetic processes. The OES measurements are performed on pure argon plasmas at intermediate pressure. Besides, hydrogen and hydrogen-silane plasmas are investigated using argon as a trace gas. Especially for the gas mixture discharges, CRMs for low and high pressure differ substantially. The commonly used line-ratio technique is found to lose its sensitivity for gas mixture discharges at higher pressure. A solution using absolutely calibrated line intensities is proposed. The effect of radiation trapping and the shape of the electron energy distribution function on the results are discussed in detail, as they have been found to significantly influence the results. This work was supported by the Ruhr University Research School PLUS, funded by Germany's Excellence Initiative [DFG GSC 98/3].

  17. Six Balmer-dominated supernova remnants

    SciTech Connect

    Smith, R.C.; Kirshner, R.P.; Blair, W.P.; Winkler, P.F. Johns Hopkins University, Baltimore, MD Middlebury College, VT )

    1991-07-01

    Spectra of six Balmer-dominated SNRs are examined: the Galactic SNR of SN 1572 and SN 1006, the LMC SNR 0505-67.9, 0509-67.5, 0519-69.0, and 0548-70.4. A shock velocity is derived for each SNR with broad H-alpha and a possible lower limit of the shock velocity in 0509-67.5. Models are used which show that the use of the ratio of broad to narrow intensity as an indicator of shock velocity is not reliable. The observed intensity ratios do not correspond to either the commonly assumed case of no equilibration or to the other extreme of total equilibration. Distances to the filaments in SN 1572 and SN 1006 of 1.5-3.1 kpc and 1.4-2.8 kpc, respectively, are obtained. The ages are estimated to range from about 10,000 yr for 0505-67.9 and 0548-70.4 to less than 1500 yr for the small SNR 0509-67.5 and 0519-69.0.l. These two young SNR bring the number of SNe in the LMC to at least five in the past 1500 yr, making the SN rate per unit luminosity comparable to that reported for late spiral galaxies. 40 refs.

  18. Spectropolarimetry of the molecular hydrogen line emission from OMC-1

    NASA Technical Reports Server (NTRS)

    Burton, Michael G.; Hough, J. H.; Axon, David J.; Hasegawa, T.; Tamura, M.

    1988-01-01

    Observations of the H2 v = 1-0 S(1) line at 35 km/s velocity resolution were obtained at several locations within OMC-1, including the molecular hydrogen reflection nebula. All line profiles are smooth and show no evidence for being composed of discrete components. The data are discussed with respect to a model for the H2 line formation in which the emission originates in discrete clumps moving at different velocities. It is suggested that the extended blue wing may come from fast-moving clumps embedded in a wind.

  19. Proton transport and auroral optical emissions. Ph.D. Thesis

    SciTech Connect

    Shen, D.

    1993-12-31

    The hydrogen lines are the characteristic emissions of proton aurora and have been used to study the impact of protons upon the atmosphere. Observations of hydrogen emission on the long wavelength side of the unshifted lines were not explained by previous theories. To explain the observed optical emissions, a numerical code is developed to solve the one dimensional, steady state, linearly coupled transport equations of H(+)/H in a dipole magnetic field. The mirror force is included in the transport equations to produce backscattered particles which are responsible for emission at wavelengths longward of the unshifted lines. Both downward and upward particle intensities of H(+)/H are calculated. The mirror reflectivities of energy and particles are defined, and their dependences on proton input spectra and pitch angle distributions are studied. The results show that the mirror reflectivity increases both with characteristic energy and with pitch angle of the input proton flux, but is more sensitive to angular distributions than to energy spectra. Energy deposition rate, ionization rate, H alpha, H beta, and nitrogen first negative bands emission rates and profiles are calculated. Calculated fluxes of H(+)/H and emission properties of hydrogen Balmer lines are compared with a rocket measurement. The efficiency for production of the Balmer lines and the nitrogen first negative bands is obtained in terms of the energy input rate and the H(+) particle flux. A Doppler shift of about 3.0 A toward the blue for magnetic zenith profiles of H alpha is obtained, compared with observational results of 6.0 +/- 2.0 A. The calculated emissions on the red side of the unshifted hydrogen atomic emission lines when convolved with the instrumental function account for the observed emissions on the long wavelength side of the unshifted hydrogen Balmer lines.

  20. On emission from a hydrogen-like atom

    NASA Astrophysics Data System (ADS)

    Skobelev, V. V.

    2016-02-01

    A solution of the Dirac equation for an electron in the field of a point nucleus ( Ze) has been obtained as an eigenfunction of the Schrödinger Hamiltonian and the spin projection operator Σ3. With the use of this solution, the probability W (ν) of the emission of a neutrino per unit time from a hydrogen-like atom, (Ze)* to (Ze) + ν bar ν, has been calculated for the first time in the first order of the parameter Ze ≪ 1. The probability W (ν) appears to be rather small, and the corresponding lifetime τ(ν) = [ W (ν)]-1 is much larger than the age of the Universe; correspondingly, this process cannot affect the balance of low-energy neutrinos. The smallness of W (ν) is due not only to the presence of the obvious "weak" factor ( Gm p 2 )2( m/ mp)4 in the expression for W (ν), but also primarily to the "electromagnetic" factor ( Zα)12, which can be revealed only in a particular calculation. It has been argued within quantum electrodynamics with the mentioned wavefunctions that photon emission, ( Ze)* → ( Ze) + γ, can be absent (analysis of photon emission requires the further development of the method), whereas axion emission, ( Ze)* → ( Ze) + a, can occur, although the last two effects have not been considered in detail.

  1. Updated cost estimates of meeting geothermal hydrogen sulfide emission regulations

    SciTech Connect

    Wells, K.D.; Currie, J.W.; Weakley, S.A.; Ballinger, M.Y.

    1981-08-01

    A means of estimating the cost of hydrogen sulfide (H/sub 2/S) emission control was investigated. This study was designed to derive H/sub 2/S emission abatement cost functions and illustrate the cost of H/sub 2/S emission abatement at a hydrothermal site. Four tasks were undertaken: document the release of H/sub 2/S associated with geothermal development; review H/sub 2/S environmental standards; develop functional relationships that may be used to estimate the most cose-effective available H/sub 2/S abatement process; and use the cost functions to generate abatement cost estimates for a specific site. The conclusions and recommendations derived from the research are presented. The definition of the term impacts as used in this research is discussed and current estimates of the highest expected H/sub 2/S concentrations of in geothermal reservoirs are provided. Regulations governing H/sub 2/S emissions are reviewed and a review of H/sub 2/S control technology and a summary of the control cost functions are included. A case study is presented to illustrate H/sub 2/S abatement costs at the Baca KGRA in New Mexico.

  2. Hydrogen recombination at high optical depth and the spectrum of SN 1987A

    NASA Technical Reports Server (NTRS)

    Xu, Yueming; Mccray, Richard; Oliva, Ernesto; Randich, Sofia

    1992-01-01

    A general theory is presented for hydrogen recombination line formation in an expanding medium in which some of the lines are optically thick. This theory is used to calculate the time evolution of the hydrogen lines of SN 1987A at t equal to or greater than 150 days, assuming that the supernova envelope is a homologously expanding uniform sphere. The theoretical luminosities and ratios of the recombination lines agree remarkably well with the observations. For the first 2 yr, the supernova envelope is optically thick to Balmer continuum. For t equal to or less than 400 days, hydrogen is ionized primarily from the n = 2 level by Balmer continuum photons, which are provided partly by the two-photon decay of the 2s state and partly by emission lines of heavy elements.

  3. Spectroscopy of Molecular Hydrogen Emission from KH 15D

    NASA Astrophysics Data System (ADS)

    Deming, Drake; Charbonneau, David; Harrington, Joseph

    2004-01-01

    We report infrared spectroscopy of the unusual eclipsing pre-main-sequence object KH 15D, obtained using NIRSPEC on Keck II. During eclipse, observations using low spectral resolution (λ/δλ~1000) reveal the presence of prominent molecular hydrogen emission in five lines near 2 μm. The relative line strengths are consistent with thermal excitation at T~2800+/-300 K. Observations out of eclipse, at both low and high spectral resolution (λ/δλ~2×104), show reduced contrast with the stellar continuum. The change in contrast for the strongest line, 1-0 S(1), is consistent with an approximately constant emission line superposed on a variable stellar continuum. Emission in the 1-0 S(1) line is observed to extend by >~4" both east and west of the stellar point-spread function (PSF; >~3000 AU). Observed at high spectral resolution, the velocity and the intensity structure of the 1-0 S(1) profile are both asymmetric. East of the stellar PSF (by 1.1"-2.3") the emission is blueshifted (-63 km s-1) and has significantly greater intensity than the marginally redshifted component (+2 km s-1, approximately consistent with zero) that dominates west of the stellar PSF. The spatial extent of the emission and the excitation temperature suggest shock excitation of ambient gas by a bipolar outflow from the star and/or the disk. However, it is difficult to account for the observed radial velocity unless the outflow axis is inclined significantly to the plane of the sky. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  4. Laser plasma diagnostics and self-absorption measurements of the Hβ Balmer series line

    NASA Astrophysics Data System (ADS)

    Gautam, Ghaneshwar; Parigger, Christian G.; Surmick, David M.; EL Sherbini, Ashraf M.

    2016-02-01

    In this work, the peak-separation of the Balmer series hydrogen beta line was measured to determine the electron density of laser-induced plasma from spatially and temporally resolved spectra collected in laboratory air at standard ambient temperature and pressure. The self-absorption phenomenon is investigated by using a mirror that retro-reflects the emitted radiation through the plasma. The experimental data with and without the mirror were analyzed with available hydrogen beta computer simulations. Hardly any self-absorption was found as indicated by the correction factors that only marginally differ from unity. The obtained electron density values are also compared with the electron densities from nearby nitrogen lines. The hydrogen beta Hβ peak-separation method yields reliable results for an electron density of the order of 1 ×1017cm-3 for time delays of 5 μs from plasma generation, which confirms that self-absorption is insignificant for such electron densities.

  5. The Influence of Gas Composition in Dielectric Barrier Discharges on the Broadening of the Hydrogen H{alpha} Transition

    SciTech Connect

    Janus, H. W.

    2006-01-15

    The distribution of hydrogen atoms responsible for emission of the Balmer H{alpha} line in the region of the dielectric barrier discharges in the helium and hydrogen as well as in the argon and hydrogen mixtures, in the direction perpendicular to the electrode surfaces, has bee determined by the optical emission spectroscopy accounting for the polarization of the emitted light. The procedure of fitting the measured line profiles accounting for the Stark effect has been used for determination of the distribution of the electric field in the discharge region.

  6. Temperature enhancement of secondary electron emission from hydrogenated diamond films

    SciTech Connect

    Stacey, A.; Prawer, S.; Rubanov, S.; Akhvlediani, R.; Michaelson, Sh.; Hoffman, A.

    2009-09-15

    The effect of temperature on the stability of the secondary electron emission (SEE) yield from approx100-nm-thick continuous diamond films is reported. At room temperature, the SEE yield was found to decay as a function of electron irradiation dose. The SEE yield is observed to increase significantly upon heating of the diamond surface. Furthermore, by employing moderate temperatures, the decay of the SEE yield observed at room temperature is inhibited, showing a nearly constant yield with electron dose at 200 deg. C. The results are explained in terms of the temperature dependence of the electron beam-induced hydrogen desorption from the diamond surface and surface band bending. These findings demonstrate that the longevity of diamond films in practical applications of SEE can be increased by moderate heating.

  7. Mitigation of hydrogen sulfide emissions in The Geysers KGRA

    SciTech Connect

    Buell, R.

    1981-07-01

    Violations of the ambient air quality standard (AAQS) for hydrogen sulfide (H/sub 2/S) are currently being experienced in The Geysers KGRA and could significantly increase in the future. Attainment and maintenance of the H/sub 2/S AAQS is a potential constraint to optimum development of this resource. The availability of reliable H/sub 2/S controls and the development of a validated air dispersion model are critical to alleviating this constraint. The purpose of this report is to assess the performance capabilities for state-of-the-art controls, to identify potential cost-effective alternative controls, and to identify the California Energy Commission (CEC) staff's efforts to develop a validated air dispersion model. Currently available controls (Stretford, Hydrogen Peroxide, and EIC) are capable of abating H/sub 2/S emissions from a proposed facility to five lbs/hr. Alternative controls, such as condensate stripping and condensate pH control, appear to be promising, cost-effective control options.

  8. The variability of the double-peaked Balmer lines in the active nucleus of NGC 1097

    NASA Technical Reports Server (NTRS)

    Storchi-Bergmann, Thaisa; Eracleous, Michael; Livio, Mario; Wilson, Andrew S.; Filippenko, Alexei V.; Halpern, Jules P.

    1995-01-01

    We present spectroscopic observations of the nucleus of the Seyfert/low-ionization nuclear emission-line region galaxy NGC 1097 spanning the period 1991-1994. The goal was to monitor anticipated variations of the broad, double-peaked Balmer lines which appeared abruptly in 1991. We find that the broad Balmer lines have varied significantly over the monitoring period, both in their integrated fluxes and in their profile shapes. The integrated H-alpha flux has decreased by a factor of 2, the (H-alpha)/(H-beta) ratio has increased, and the originally asymmetric H-alpha profile has become symmetric. The decline of the H-alpha flux and the change in the (H-alpha)/(H-beta) ratio can be interpreted as consequences of either increased obscuration along the line of sight, or a decline in the ionizing continuum, but neither of these scenarios can account for the change in profile shapes. A model attributing the line emission to a precessing elliptical ring around a 10(exp 6) solar mass nuclear black hole can reproduce the observed profile variations. In this scenario, the line-emitting ring is the result of the tidal disruption of a star by the black hole. Alternative scenarios associating the broad-line emission with a collimated bipolar outflow also remain viable, but binary black holes and inhomogeneous accretion disks are disfavored by the observed pattern of variability.

  9. Variation in the Pre-transit Balmer Line Signal Around the Hot Jupiter HD 189733b

    NASA Astrophysics Data System (ADS)

    Cauley, P. Wilson; Redfield, Seth; Jensen, Adam G.; Barman, Travis

    2016-07-01

    As followup to our recent detection of a pre-transit signal around HD 189733 b, we obtained full pre-transit phase coverage of a single planetary transit. The pre-transit signal is again detected in the Balmer lines but with variable strength and timing, suggesting that the bow shock geometry reported in our previous work does not describe the signal from the latest transit. We also demonstrate the use of the Ca ii H and K residual core flux as a proxy for the stellar activity level throughout the transit. A moderate trend is found between the pre-transit absorption signal in the 2013 data and the Ca ii H flux. This suggests that some of the 2013 pre-transit hydrogen absorption can be attributed to varying stellar activity levels. A very weak correlation is found between the Ca ii H core flux and the Balmer line absorption in the 2015 transit, hinting at a smaller contribution from stellar activity compared to the 2013 transit. We simulate how varying stellar activity levels can produce changes in the Balmer line transmission spectra. These simulations show that the strength of the 2013 and 2015 pre-transit signals can be reproduced by stellar variability. If the pre-transit signature is attributed to circumplanetary material, its evolution in time can be described by accretion clumps spiraling toward the star, although this interpretation has serious limitations. Further high-cadence monitoring at Hα is necessary to distinguish between true absorption by transiting material and short-term variations in the stellar activity level.

  10. Echo mapping the Balmer-emission region in NGC 3516

    NASA Technical Reports Server (NTRS)

    Wanders, I.; Horne, K.

    1994-01-01

    We use a maximum-entropy method to show that the transfer function (TF) of the broad-line region (BLR) in the Seyfert-1 galaxy NGC 3516 is time-varying. The TF decreased by nearly a factor of two over a time scale less than half a year during a monitoring campaign in 1990. We conclude that the observed time dependency is likely to be either due to variations of the spectral index of the ionizing continuum spectrum; due to a change in the number or covering fraction of broad-line clouds; due to nonlinear line response; or due to nonstationary anisotropy of the continuum source on time scales of several weeks to months. An extended continuum source could also explain the observed time-dependency. The symmetry of the time lag for variations in the red and blue wings of H-alpha indicates that the BLR kinematics is not dominated by organized radial inflow or outflow. If we assume circular orbits, the observed time lag 14 days at velocity v = 4000 km/s suggests a mass of the central object of approximately 2 x 10(exp 7) solar mass. The H-alpha TF peaks away from zero delay, indicating that the H-alpa BLR is either non-spherical or inwardly emitting.

  11. 40 CFR Table 4 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Hydrogen Chloride Emission Limits

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Process Heaters With Hydrogen Chloride Emission Limits 4 Table 4 to Subpart DDDDD of Part 63 Protection of... Heaters With Hydrogen Chloride Emission Limits As stated in § 63.7500, you must comply with the following applicable operating limits: If you demonstrate compliance with applicable hydrogen chloride emission...

  12. 40 CFR Table 4 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Hydrogen Chloride Emission Limits

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Process Heaters With Hydrogen Chloride Emission Limits 4 Table 4 to Subpart DDDDD of Part 63 Protection of... Heaters With Hydrogen Chloride Emission Limits As stated in § 63.7500, you must comply with the following applicable operating limits: If you demonstrate compliance with applicable hydrogen chloride emission...

  13. 40 CFR Table 4 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Hydrogen Chloride Emission Limits

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Process Heaters With Hydrogen Chloride Emission Limits 4 Table 4 to Subpart DDDDD of Part 63 Protection of... Heaters With Hydrogen Chloride Emission Limits As stated in § 63.7500, you must comply with the following applicable operating limits: If you demonstrate compliance with applicable hydrogen chloride emission...

  14. Molecular hydrogen emission as a density and temperature indicator

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Ferland, Gary J.; Baldwin, Jack A.; Loh, Edwin D.; Fabian, Andy C.; Williams, Robin

    2016-01-01

    Infrared observations have discovered a variety of objects, including filaments in the Crab Nebula and cool-core clusters of galaxies, where the 1-0 S(1) line is stronger than the infrared H I lines. A variety of processes could be responsible for this emission. Although many complete shock or PDR calculations of emission have been published, we know of no previous simple calculation that shows the emission spectrum and level populations of thermally excited low-density . We present a range of purely thermal collisional simulations, corresponding to constant gas kinetic temperature at different densities. We consider the cases where the collisions affecting H2 are predominantly with atomic or molecular hydrogen. The resulting level population (often called "excitation") diagrams show that excitation temperatures are sometimes lower than the gas kinetic temperature when the density is too low for the level populations to go to LTE. The atomic case goes to LTE at much lower densities than the molecular case due to larger collision rates. At low densities for the v=1 and 2 vibrational manifolds level populations are quasi-thermal, which could be misinterpreted as showing the gas is in LTE at high density. At low densities for the molecular case the level population diagrams are discontinuous between v=0 and 1 vibrational manifolds and between v=2, J=0, 1 and other higher J levels within the same vibrational manifold. These jumps could be used as density diagnostics. We show how much the H2 mass would be underestimated using the 1-0 S(1) line strength if the density is below that required for LTE. We give diagnostic diagrams showing level populations over a range of density and temperature. The density where the level populations are given by a Boltzmann distribution relative to the total molecular abundance (required to get the correct H2 mass), is shown for various cases. We discuss the implications of these results for the interpretation of H2 observations of the

  15. Synthetic Spectra of H Balmer and HE I Absorption Lines. I. Stellar Library

    NASA Astrophysics Data System (ADS)

    González Delgado, Rosa M.; Leitherer, Claus

    1999-12-01

    We present a grid of synthetic profiles of stellar H Balmer and He I lines at optical wavelengths with a sampling of 0.3 Å. The grid spans a range of effective temperature 50,000 K>=Teff>=4000 K, and gravity 0.0<=logg<=5.0 at solar metallicity. For Teff>=25,000 K, non-LTE stellar atmosphere models are computed using the code TLUSTY (Hubeny). For cooler stars, Kurucz LTE models are used to compute the synthetic spectra. The grid includes the profiles of the high-order hydrogen Balmer series and He I lines for effective temperatures and gravities that have not been previously synthesized. The behavior of H8 to H13 and He I λ3819 with effective temperature and gravity is very similar to that of the lower terms of the series (e.g., Hβ) and the other He I lines at longer wavelengths; therefore, they are suited for the determination of the atmospheric parameters of stars. These lines are potentially important to make predictions for these stellar absorption features in galaxies with active star formation. Evolutionary synthesis models of these lines for starburst and poststarburst galaxies are presented in a companion paper. The full set of the synthetic stellar spectra is available for retrieval at our website or on request from the authors.

  16. Fuel economy and emissions evaluation of BMW hydrogen 7 mono-fuel demonstration vehicles.

    SciTech Connect

    Wallner, T.; Lohse-Busch, H.; Gurski, S.; Duoba, M.; Thiel, W.; Martin, D.; Korn, T.; Energy Systems; BMW Group Munich Germany; BMW Group Oxnard USA

    2008-12-01

    This article summarizes the testing of two BMW Hydrogen 7 Mono-Fuel demonstration vehicles at Argonne National Laboratory's Advanced Powertrain Research Facility (APRF). The BMW Hydrogen 7 Mono-Fuel demonstration vehicles are derived from the BMW Hydrogen 7 bi-fuel vehicles and based on a BMW 760iL. The mono-fuel as well as the bi-fuel vehicle(s) is equipped with cryogenic hydrogen on-board storage and a gaseous hydrogen port fuel injection system. The BMW Hydrogen 7 Mono-Fuel demonstration vehicles were tested for fuel economy as well as emissions on the Federal Test Procedure FTP-75 cold-start test as well as the highway test. The results show that these vehicles achieve emissions levels that are only a fraction of the Super Ultra Low Emissions Vehicle (SULEV) standard for nitric oxide (NO{sub x}) and carbon monoxide (CO) emissions. For non-methane hydrocarbon (NMHC) emissions the cycle-averaged emissions are actually 0 g/mile, which require the car to actively reduce emissions compared to the ambient concentration. The fuel economy numbers on the FTP-75 test were 3.7 kg of hydrogen per 100 km, which, on an energy basis, is equivalent to a gasoline fuel consumption of 17 miles per gallon (mpg). Fuel economy numbers for the highway cycle were determined to be 2.1 kg of hydrogen per 100 km or 30 miles per gallon of gasoline equivalent (GGE). In addition to cycle-averaged emissions and fuel economy numbers, time-resolved (modal) emissions as well as air/fuel ratio data is analyzed to further investigate the root causes of the remaining emissions traces. The BMW Hydrogen 7 vehicles employ a switching strategy with lean engine operation at low engine loads and stoichiometric operation at high engine loads that avoids the NO{sub x} emissions critical operating regime with relative air/fuel ratios between 1 < {lambda} < 2. The switching between these operating modes was found to be a major source of the remaining NO{sub x} emissions. The emissions results collected

  17. Intermittent control procedures for the Geysers hydrogen sulfide emission abatement

    SciTech Connect

    Buick, B.D.; Mooney, M.L.

    1984-01-01

    Pacific Gas and Electric Company (PG and E) operates the world's largest geothermal steam electric power generation facility, currently about 1.140 megawatts (Mw). This facility is located about 80 miles north of San Francisco, California and is within a region referred to as the Known Geothermal Resource Area (KGRA). Pollutants resulting from this method of electric power generation are due to impurities in the geothermal steam. A major contaminate in the steam is hydrogen sulfide (H/sub 2/S), a regulated pollutant in California. The ambient air quality standard (AAQS) for this pollutant in California is 0.03 parts per million (ppM) averaged over one hour. H/sub 2/S is an invisible, unpleasant smelling gas present in varying concentrations in the geothermal steam. Its odor has been compared to the smell of rotten eggs. Since PG and E is increasingly relying on this source of electrical power generation, it has committed millions of dollars to the development, testing, acquisition, and installation of abatement equipment to reduce H/sub 2/S emissions during the past ten years. In order to reduce the number of exceeds of the AAQS during this developmental period, a predictive model was needed for interim abatement purposes. Most of the high hourly H/sub 2/S values occur with meteorological conditions having poor ventilation resulting from a combination of low wind speed and reduced mixing layer depths. This weather condition is most common during the months of June through October in California. A predictive model was developed from three years of hourly H/sub 2/S measurements of 0.03 ppM or greater in populated areas downwind of the generation facility and from observations of associated meteorological data.

  18. Maximizing light emission from silicon nanocrystals - The role of hydrogen

    NASA Astrophysics Data System (ADS)

    Wilkinson, A. R.; Elliman, R. G.

    2006-01-01

    Time-resolved photoluminescence measurements are undertaken to determine the passivation kinetics of luminescence-quenching defects during isothermal and isochronal annealing in molecular and atomic hydrogen. The latter employs an alneal process in which atomic hydrogen is generated by reactions between a deposited Al layer and H2O or -OH radicals in the SiO2. Passivation and desorption kinetics are shown to be consistent with the existence of two classes of non-radiative defects: one that reacts with either atomic or molecular hydrogen, and the other that reacts only with atomic hydrogen.

  19. Anomalous Balmer continuum temperatures in the Orion Nebula

    NASA Technical Reports Server (NTRS)

    Walter, Donald L.; Dufour, Reginald J.

    1994-01-01

    New long-slit spectra of the Orion Nebula in the near-ultraviolet were used to calculate the Balmer recombination temperature, T(Bac), from the Balmer discontinuity at 3646 A. The spatially resolved data show a decrease in temperature moving to the west of Theta(sup 1) Ori C, from 8400 K at a distance of 40 sec to a low of 2800 K at a distance of 220 sec. Such values are much lower than previously reported. The effect of scattered starlight on these results is calculated and shown to be less than 10%. Previous studies which found scattered light to be important at the discontinuity are in error. Such low temperatures and their impact on nebular physics and abundances are disconcerting and require further study.

  20. Influence of water injection on performance and emissions of a direct-injection hydrogen research engine.

    SciTech Connect

    Nande, A. M.; Wallner, T.; Naber, J.

    2008-10-06

    The application of hydrogen (H{sub 2}) as an internal combustion (IC) engine fuel has been under investigation for several decades. The favorable physical properties of hydrogen make it an excellent alternative fuel for IC engines and hence it is widely regarded as the energy carrier of the future. Direct injection of hydrogen allows optimizing this potential as it provides multiple degrees of freedom to influence the in-cylinder combustion processes and consequently engine efficiency and exhaust emissions.

  1. Spatially Resolved Dust Maps from Balmer Decrements in Galaxies at z ~ 1.4

    NASA Astrophysics Data System (ADS)

    Nelson, Erica June; van Dokkum, Pieter G.; Momcheva, Ivelina G.; Brammer, Gabriel B.; Wuyts, Stijn; Franx, Marijn; Förster Schreiber, Natascha M.; Whitaker, Katherine E.; Skelton, Rosalind E.

    2016-01-01

    We derive average radial gradients in the dust attenuation toward H ii regions in 609 galaxies at z ˜ 1.4, using measurements of the Balmer decrement out to r ˜ 3 kpc. The Balmer decrements are derived from spatially resolved maps of Hα and Hβ emission from the 3D-HST survey. We find that with increasing stellar mass M both the normalization and strength of the gradient in dust attenuation increases. Galaxies with a mean mass of < {log} M> =9.2M⊙ have little dust attenuation at all radii, whereas galaxies with < {log} M> =10.2M⊙ have AHα ≈ 2 mag in their central regions. We parameterize this as {A}{{H}α }=b+c{log} r, with b=0.9+{log}1.0{M}10, c = -1.9-2.2 log M10, r in kpc, and M10 the stellar mass in units of 1010 M⊙. This expression can be used to correct spatially resolved measurements of Hα to radial distributions of star formation. When applied to our data, we find that the star formation rates (SFRs) in the central r < 1 kpc of galaxies in the highest mass bin are ˜6 M⊙ yr-1, six times higher than before correction and approximately half of the total SFR of these galaxies. If this high central SFR is maintained for several Gyr, a large fraction of the stars in present-day bulges likely formed in situ.

  2. A STUDY TO EVALUATE CARBON MONOXIDE AND HYDROGEN SULFIDE CONTINUOUS EMISSION MONITORS AT AN OIL REFINERY

    EPA Science Inventory

    An eleven month field evaluation was done on five hydrogen sulfide and four carbon monoxide monitors located at an oil refinery. The hydrogen sulfide monitors sampled a fuel gas feed line and the carbon monoxide monitors sampled the emissions from a fluid cat cracker (FCC). Two o...

  3. Hydrogen production rate from comet Austin 1982g

    NASA Technical Reports Server (NTRS)

    Shih, P.; Scherb, F.; Roesler, F. L.

    1984-01-01

    Meaningful measurements with respect to the cometary Balmer-alpha (H-alpha) emission are difficult and require the use of special equipment. The first ground-based observations of H-alpha emission from a cometary hydrogen corona were conducted on comet Kohoutek 1973 XII with a large-aperture Fabry-Perot spectrometer installed at the McMath solar telescope at Kitt Peak National Observatory. The present investigation is concerned with the second ground-based observations of cometary H-alpha emission carried out during the apparition of comet Austin 1982g. A 150 mm dual-etalon Fabry-Perot spectrometer was employed in the experiment. Use was made of an observatory which is designed for the high spectral resolution study of faint extended sources such as interstellar and geocoronal emission lines. The investigation demonstrates that hydrogen production rates from comets as faint as about 7th magnitude can be routinely measured from the ground at minimal cost.

  4. Hydrogen and methanol: a comparison of safety, economics, efficiencies and emissions

    NASA Astrophysics Data System (ADS)

    Adamson, Kerry-Ann; Pearson, Peter

    Fuel cell cars will appear on the market early in the next century. A question still remains — whether these vehicles will store onboard, hydrogen or, the hydrogen-rich carrier, methanol. There are a number of key areas surrounding this question, three of which are safety, economics and efficiency and emissions. Each of these issues was examined using the available literature. It can be seen that it is only with emissions that a clear difference appears and then hydrogen shows an advantage over methanol.

  5. Projected Cost, Energy Use, and Emissions of Hydrogen Technologies for Fuel Cell Vehicles

    SciTech Connect

    Ruth, M. F.; Diakov, V.; Laffen, M. J.; Timbario, T. A.

    2010-01-01

    Each combination of technologies necessary to produce, deliver, and distribute hydrogen for transportation use has a corresponding levelized cost, energy requirement, and greenhouse gas emission profile depending upon the technologies' efficiencies and costs. Understanding the technical status, potential, and tradeoffs is necessary to properly allocate research and development (R&D) funding. In this paper, levelized delivered hydrogen costs, pathway energy use, and well-to-wheels (WTW) energy use and emissions are reported for multiple hydrogen production, delivery, and distribution pathways. Technologies analyzed include both central and distributed reforming of natural gas and electrolysis of water, and central hydrogen production from biomass and coal. Delivery options analyzed include trucks carrying liquid hydrogen and pipelines carrying gaseous hydrogen. Projected costs, energy use, and emissions for current technologies (technology that has been developed to at least the bench-scale, extrapolated to commercial-scale) are reported. Results compare favorably with those for gasoline, diesel, and E85 used in current internal combustion engine (ICE) vehicles, gasoline hybrid electric vehicles (HEVs), and flexible fuel vehicles. Sensitivities of pathway cost, pathway energy use, WTW energy use, and WTW emissions to important primary parameters were examined as an aid in understanding the benefits of various options. Sensitivity studies on production process energy efficiency, total production process capital investment, feed stock cost, production facility operating capacity, electricity grid mix, hydrogen vehicle market penetration, distance from the hydrogen production facility to city gate, and other parameters are reported. The Hydrogen Macro-System Model (MSM) was used for this analysis. The MSM estimates the cost, energy use, and emissions trade offs of various hydrogen production, delivery, and distribution pathways under consideration. The MSM links the H2

  6. Manure ammonia and hydrogen sulfide emissions from a Western dairy storage basin.

    PubMed

    Grant, Richard H; Boehm, Matthew T

    2015-01-01

    The reporting of ammonia (NH) and hydrogen sulfide (HS) emissions from dairies to the federal government depends on the magnitude of the emissions. However, little is known about their daily NH and HS emissions and what influences those emissions. Emissions of NH and HS from two manure storage basins at a 4400-head western free-stall dairy were measured intermittently over 2 yr. Each basin went through stages of filling, drying, and then removal of the manure during the study period. Emissions were determined using backward Lagrangian Stochastic and vertical radial plume methods. Ammonia emissions ranged from 35 to 59 kg d in one basin and from 86 to 90 kg d in a second basin, corresponding to a range of 7 to 19 g d head. Basin NH emissions were highest during initial filling and when the manure was removed. Mean HS emissions ranged from 5 to 22 kg d (1.1-4.6 g d head). Basin HS emissions were highest when the basin was filling. Crusting of the basin surface reduced NH but not HS emissions. The cessation of basin filling reduced HS but not NH emissions. Air temperature and wind conditions were correlated with NH emissions. Barometric pressure decreases were correlated with episodic HS emissions. The variability in emissions with stage of manure handling and storage and meteorological conditions indicates that determining the maximum daily emissions and the annual emissions from such waste basins requires consideration of each stage in conjunction with the climatic conditions during the stage. PMID:25602327

  7. [Study on the Emission Spectrum of Hydrogen Production with Microwave Discharge Plasma in Ethanol Solution].

    PubMed

    Sun, Bing; Wang, Bo; Zhu, Xiao-mei; Yan, Zhi-yu; Liu, Yong-jun; Liu, Hui

    2016-03-01

    Hydrogen is regarded as a kind of clean energy with high caloricity and non-pollution, which has been studied by many experts and scholars home and abroad. Microwave discharge plasma shows light future in the area of hydrogen production from ethanol solution, providing a new way to produce hydrogen. In order to further improve the technology and analyze the mechanism of hydrogen production with microwave discharge in liquid, emission spectrum of hydrogen production by microwave discharge plasma in ethanol solution was being studied. In this paper, plasma was generated on the top of electrode by 2.45 GHz microwave, and the spectral characteristics of hydrogen production from ethanol by microwave discharge in liquid were being studied using emission spectrometer. The results showed that a large number of H, O, OH, CH, C2 and other active particles could be produced in the process of hydrogen production from ethanol by microwave discharge in liquid. The emission spectrum intensity of OH, H, O radicals generated from ethanol is far more than that generated from pure water. Bond of O-H split by more high-energy particles from water molecule was more difficult than that from ethanol molecule, so in the process of hydrogen production by microwave discharge plasma in ethanol solution; the main source of hydrogen was the dehydrogenation and restructuring of ethanol molecules instead of water decomposition. Under the definite external pressure and temperature, the emission spectrum intensity of OH, H, O radicals increased with the increase of microwave power markedly, but the emission spectrum intensity of CH, C2 active particles had the tendency to decrease with the increase of microwave power. It indicated that the number of high energy electrons and active particles high energy electron energy increased as the increase of microwave power, so more CH, C2 active particles were split more thoroughly. PMID:27400531

  8. Improvement of Electron Field Emission in Patterned Carbon Nanotubes by High Temperature Hydrogen Plasma Treatment

    PubMed Central

    Wang, Sigen; Sellin, Paul. J.; Lian, Jun; Özsan, Ersin; Chang, Sha

    2009-01-01

    In this paper, we report a significant improvement of electron field emission property in patterned carbon nanotubes films by using a high temperature (650 °C) hydrogen plasma treatment. This treatment was found to greatly increase the emission current, emission uniformity and stability. The mechanism study showed that these enhanced properties are attributed to the lowering of the potential barrier and the creation of geometrical features through the removal of amorphous carbon, catalyst particles and the saturation of dangling bonds after such a hydrogen plasma treatment. PMID:19946566

  9. Effect of exogenous hydrogen peroxide on biophoton emission from radish root cells.

    PubMed

    Rastogi, Anshu; Pospísil, Pavel

    2010-01-01

    Biophotons spontaneously emitted from radish root cells were detected using highly sensitive photomultiplier tube. Freshly isolated radish root cells exhibited spontaneous photon emission of about 4 counts s(-1). Addition of hydrogen peroxide to the cells caused significant enhancement in biophoton emission to about 500 counts s(-1). Removal of molecular oxygen using glucose/glucose oxidase system and scavengering of reactive oxygen species by reducing agents such are sodium ascorbate and cysteine completely diminished biophoton emission. Spectral analysis of the hydrogen peroxide-induced biophoton emission indicates that biophotons are emitted mainly in green-red region of the spectra. The data provided by electron paramagnetic resonance spin-trapping technique showed that formation of singlet oxygen observed after addition of H2O2 correlates with enhancement in biophoton emission. These observations provide direct evidence that singlet oxygen is involved in biophoton emission from radish root cells. PMID:20106674

  10. Hydrogen two-photon continuum emission from the Horseshoe filament in NGC 1275

    NASA Astrophysics Data System (ADS)

    Johnstone, R. M.; Canning, R. E. A.; Fabian, A. C.; Ferland, G. J.; Lykins, M.; Porter, R. L.; van Hoof, P. A. M.; Williams, R. J. R.

    2012-09-01

    Far-ultraviolet emission has been detected from a knot of Hα emission in the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected relative to the brightness of the Hα line in the same spatial region is very close to that expected from hydrogen two-photon continuum emission in the particle heating model of Ferland et al. if reddening internal to the filaments is taken into account. We find no need to invoke other sources of far-ultraviolet emission such as hot stars or emission lines from C IV in intermediate-temperature gas to explain these data.

  11. Hydrogen Gas Emissions from Active Faults and Identification of Flow Pathway in a Fault Zone

    NASA Astrophysics Data System (ADS)

    Ishimaru, T.; Niwa, M.; Kurosawa, H.; Shimada, K.

    2010-12-01

    It has been observed that hydrogen gas emissions from the subsurface along active faults exceed atmospheric concentrations (e.g. Sugisaki et. al., 1983). Experimental studies have shown that hydrogen gas is generated in a radical reaction of water with fractured silicate minerals due to rock fracturing caused by fault movement (e.g. Kita et al., 1982). Based on such research, we are studying an investigation method for an assessment of fault activity using hydrogen gas emissions from fracture zones. To start, we have devised portable equipment for rapid and simple in situ measurement of hydrogen gas emissions (Shimada et al., 2008). The key component of this equipment is a commercially available and compact hydrogen gas sensor with an integral data logger operable at atmospheric pressure. In the field, we have drilled shallow boreholes into incohesive fault rocks to depths ranging from 15 to 45 cm using a hand-operated drill with a 9mm drill-bit. Then, we have measured the hydrogen gas concentrations in emissions from active faults such as: the western part of the Atotsugawa fault zone, the Atera fault zone and the Neodani fault in central Japan; the Yamasaki fault zone in southwest Japan; and the Yamagata fault zone in northeast Japan. In addition, we have investigated the hydrogen gas concentrations in emissions from other major geological features such as tectonic lines: the Butsuzo Tectonic Line in the eastern Kii Peninsula and the Atokura Nappe in the Northeastern Kanto Mountains. As a result of the investigations, hydrogen gas concentration in emissions from the active faults was measured to be in the approximate range from 6,000 ppm to 26,000 ppm in two to three hours after drilling. A tendency for high concentrations of hydrogen gas in active faults was recognized, in contrast with low concentrations in emissions from tectonic lines that were observed to be in the range from 730 ppm to 2,000 ppm. It is inferred that the hydrogen gas migrates to ground

  12. Global Assessment of Hydrogen Technologies - Task 2 Report Comparison of Performance and Emissions from Near-Term Hydrogen Fueled Light Duty Vehicles

    SciTech Connect

    Fouad, Fouad H.; Peters, Robert W.; Sisiopiku, Virginia P.; Sullivan Andrew J.; Ng, Henry K.; Waller, Thomas

    2007-12-01

    An investigation was conducted on the emissions and efficiency from hydrogen blended compressed natural gas (CNG) in light duty vehicles. The different blends used in this investigation were 0%, 15%, 30%, 50%, 80%, 95%, and ~100% hydrogen, the remainder being compressed natural gas. The blends were tested using a Ford F-150 and a Chevrolet Silverado truck supplied by Arizona Public Services. Tests on emissions were performed using four different driving condition tests. Previous investigation by Don Karner and James Frankfort on a similar Ford F-150 using a 30% hydrogen blend showed that there was substantial reduction when compared to gasoline in carbon monoxide (CO), nitrogen oxide (NOx), and carbon dioxide (CO2) emissions while the reduction in hydrocarbon (HC) emissions was minimal. This investigation was performed using different blends of CNG and hydrogen to evaluate the emissions reducing capabilities associated with the use of the different fuel blends. The results were then tested statistically to confirm or reject the hypotheses on the emission reduction capabilities. Statistically analysis was performed on the test results to determine whether hydrogen concentration in the HCNG had any effect on the emissions and the fuel efficiency. It was found that emissions from hydrogen blended compressed natural gas were a function of driving condition employed. Emissions were found to be dependent on the concentration of hydrogen in the compressed natural gas fuel blend.

  13. The interstellar wind - Mariner 10 measurements of hydrogen /1216 A/ and helium /584 A/ interplanetary emission

    NASA Technical Reports Server (NTRS)

    Broadfoot, A. L.; Kumar, S.

    1978-01-01

    A set of unique observations of interplanetary emission at 1216 A and 584 A is presented which were made from Mariner 10 when that spacecraft was in interplanetary space on its way to Venus. The data provide simultaneous mapping of 1216-A hydrogen emission and 584-A helium emission, which allows a direct cross-correlation of these two aspects of the interstellar wind. The data are examined photometrically and compared with the principles of a simple model which provides a first-order understanding of the expected intensity variation over the celestial sphere. Hydrogen and helium sky maps are given which indicate the minima and maxima in emission intensity, a helium-focusing region in excess of 50 to 60 deg, and asymmetries in both emission profiles.

  14. Use of AERMOD to Determine a Hydrogen Sulfide Emission Factor for Swine Operations by Inverse Modeling

    PubMed Central

    O’Shaughnessy, Patrick T.; Altmaier, Ralph

    2011-01-01

    This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 µg/m2-s was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10−7 µg/yr-m2-kg was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1M kg), concentrations 0.5 km from the CAFO were 35 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels. PMID:21804761

  15. Use of AERMOD to Determine a Hydrogen Sulfide Emission Factor for Swine Operations by Inverse Modeling.

    PubMed

    O'Shaughnessy, Patrick T; Altmaier, Ralph

    2011-08-01

    This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 µg/m(2)-s was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10(-7) µg/yr-m(2)-kg was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1M kg), concentrations 0.5 km from the CAFO were 35 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels. PMID:21804761

  16. Use of AERMOD to determine a hydrogen sulfide emission factor for swine operations by inverse modeling

    NASA Astrophysics Data System (ADS)

    O'Shaughnessy, Patrick T.; Altmaier, Ralph

    2011-09-01

    This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 μg m -2 s -1 was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10 -7 μg yr -1 m -2 kg -1 was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1 M kg), concentrations within 0.5 km from the CAFO exceeded 25 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels.

  17. Doppler broadening of atomic-hydrogen lines in DC and capacitively coupled RF plasmas

    NASA Astrophysics Data System (ADS)

    Akhtar, Kamran; Scharer, J. E.; Mills, R. L.

    2007-10-01

    The extraordinary broadening of Balmer lines of hydrogen admixed with Ar or He as opposed to Xe in DC glow and capacitively coupled rf discharges is studied over a wide range of pressure and gas compositions. High-resolution optical emission spectroscopy is performed parallel to (end-on) and perpendicular (side-on) to the electrode axis along with Langmuir probe measurements of plasma density and electron temperature for the RF capacitive discharge case. A broad and symmetric (Gaussian) Balmer emission line corresponding to 20-60 eV hydrogen atom temperatures is observed in Ar/H2 and He/H2 plasmas. Energy is transferred selectively to hydrogen atoms whereas the atoms of admixed He and Ar gases remain cold (<0.5 eV). In the field acceleration model [e.g., Cvetanovic et. al. J. App. Phys., Vol. 97, 033302-1, 2005] there apparently is no preferred species to which energy is coupled and according to the model one should observe enhanced temperatures of hydrogen and helium atoms in He/H2 discharges where the atomic mass is more comparable (4:1). We also briefly examine the experimental results using the Resonance Transfer Model of hydrogen heating [Mills et. al IEEE Trans. Plasma Sci., 31, 338, 2003] as the source of broadening.

  18. Spectroscopic investigations into extraordinary phenomena in hydrogen plasmas with certain catalysts

    NASA Astrophysics Data System (ADS)

    Nijdam, Sander; van den Brink, Andreas; Driessen, Niels; van Noorden, Peter; de Regt, Ruud; Righart, Tim; Sitters, Gerrit; van Veldhuizen, Eddie; Wijtvliet, Ruud; Kroesen, Gerrit

    2007-10-01

    In recent years hydrogen plasmas have been created that display extraordinary behavior, like breakdown at low electric fields, anomalous plasma afterglow, excessive hydrogen Balmer-α spectral line broadening and EUV and VUV emission. Experiments have been done on three types of hydrogen discharges in order to reproduce the extraordinary plasma behavior observed. We have investigated these hydrogen discharges with different spectroscopic measuring devices. We focused on broadening of the hydrogen Balmer-α line and the emission of EUV and VUV radiation. The measurements in the visible part of the spectrum have been performed using a B&M-100 type (1000 mm) Czerny-Turner monochromator attached to a CCD camera or a photomultiplier. For the VUV and EUV measurements we have used three different monochromators: a Jobin Yvon LHT 30 (320 mm, near grazing incidence), a Jobin Yvon HR 1500 (1500 mm, normal incidence) and a McPherson Model 234/302 vacuum monochromator (200 mm, normal incidence). In all cases a scintillator plate has been used to convert the diffracted UV radiation into visible light which was quantified by a CCD camera or a photomultiplier.

  19. Low Emission Hydrogen Combustors for Gas Turbines Using Lean Direct Injection

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Smith, Timothy D.; Kundu, Krishna

    2005-01-01

    One of the key technology challenges for the use of hydrogen in gas turbine engines is the performance of the combustion system, in particular the fuel injectors. To investigate the combustion performance of gaseous hydrogen fuel injectors flame tube combustor experiments were performed. Tests were conducted to measure the nitrogen oxide (NOx) emissions and combustion performance at inlet conditions of 600 to 1000 deg F, 60 to 200 pounds per square inch absolute (psia), and equivalence ratios up to 0.48. All the injectors were based on Lean Direct Injection (LDI) technology with multiple injection points and quick mixing. One challenge to hydrogen based premixing combustion systems is flashback since hydrogen has a reaction rate over seven times that of Jet-A. To reduce the risk, design mixing times were kept short and velocities high to minimize flashback. Five fuel injector designs were tested in 2.5 and 3.5-in. diameter flame tubes with non-vitiated heated air and gaseous hydrogen. Data is presented on measurements of NOx emissions and combustion efficiency for the hydrogen injectors at 1.0, 3.125, and 5.375 in. from the injector face. Results show that for some configurations, NOx emissions are comparable to that of state of the art Jet-A LDI combustor concepts.

  20. Low-Emission Hydrogen Combustors for Gas Turbines Using Lean Direct Injection

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Smith, Timothy D.; Kundu, Krishna

    2007-01-01

    One of the key technology challenges for the use of hydrogen in gas turbine engines is the performance of the combustion system, in particular the fuel injectors. To investigate the combustion performance of gaseous hydrogen fuel injectors flame tube combustor experiments were performed. Tests were conducted to measure the nitrogen oxide (NO(x)) emissions and combustion performance at inlet conditions of 588 to 811 K, 0.4 to 1.4 MPa, and equivalence ratios up to 0.48. All the injectors were based on Lean Direct Injection (LDI) technology with multiple injection points and quick mixing. One challenge to hydrogen-based premixing combustion systems is flashback since hydrogen has a reaction rate over 7 times that of Jet-A. To reduce the risk, design mixing times were kept short and velocities high to minimize flashback. Five fuel injector designs were tested in 6.35- and 8.9-cm-diameter flame tubes with non-vitiated heated air and gaseous hydrogen. Data is presented on measurements of NO(x) emissions and combustion efficiency for the hydrogen injectors at 2.540, 7.937, and 13.652 cm from the injector face. Results show that for some configurations, NO(x) emissions are comparable to that of state of the art Jet-A LDI combustor concepts.

  1. VizieR Online Data Catalog: Hydrogen emission and recombination coefficients - SS2 (Storey+, 2014)

    NASA Astrophysics Data System (ADS)

    Storey, P. J.; Sochi, T.

    2014-10-01

    The data set consists of two files: e1bk.d and t1bk.d. The first file contains emission coefficients of hydrogen in units of erg.cm3/s as a function of electron density (Ne), temperature (Te) and kappa. The second file named 't1bk.d' contains the hydrogen total recombination coefficients in Case B and the total recombination coefficients to the 2s state of hydrogen in units of cm3/s as a function of Ne, Te and kappa. (5 data files).

  2. Detection of auroral hydrogen Lyman-Alpha emission from Uranus

    SciTech Connect

    Clarke, J.T.

    1982-12-15

    A series of observations of Uranus obtained with the short-wavelength spectrographs of the International Ultraviolet Explorer Observatory in 1982 April and June have revealed unexpectedly strong H Ly..cap alpha.. emission which varied between 430 and 850 Rayleighs in observed disk-averaged brightness over the course of these observations. The variability of the emission alone indicates that much of the emission must be produced by charged particle excitation of H in Uranus's upper atmosphere. In addition, comparison of these data with a model for resonant scattering of solar H Ly..cap alpha.. emission indicates that, over a wide range of model conditions, an emission brightness of even 430 Rayleighs (which was the lowest observed value) corresponds to an H column density on the order of 10/sup 17/ cm/sup -2/ in Uranus's upper atmosphere. At 20 AU from the Sun, solar EUV photodissociation of H/sub 2/ is insufficient to produce such a high column abundance of H, further supporting the identification of charged particle precipitation in Uranus's upper atmosphere. These data thus offer the first strong evidence for the presence of aurorae and therefore a magnetic field on Uranus.

  3. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    NASA Astrophysics Data System (ADS)

    Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

  4. Exospheric and interplanetary hydrogen sensing from a translunar CubeSat platform by the Tomographic Hydrogen Emission Observatory (THEO)

    NASA Astrophysics Data System (ADS)

    Waldrop, L.; Sample, J. G.; Doe, R.; Noto, J.; Walsh, B.; Kamalabadi, F.; Mierkiewicz, E. J.; Kerr, R. B.; Immel, T. J.

    2015-12-01

    The evaporation of neutral hydrogen (H) atmospheres into interplanetary space is a near-ubiquitous process in the universe that can be strongly perturbed by charge exchange coupling with ambient ions, influencing atmospheric evolution as well as the dissipation of plasma energy. Space-based observation of solar ultraviolet (UV) radiation scattered by H atoms is a powerful means to infer the underlying exospheric density distribution and thus unravel the competing effects of thermal and non-thermal processes on H energization and escape. Numerous past and present NASA missions have obtained measurements of terrestrial H emission at 121.6 nm (Lyman alpha) from earth-orbiting satellite platforms. However, their separate targeting of either the optically thick emission in the lower exosphere or the optically thin emission in the outer exosphere, together with their lack of independent measurement of the interplanetary emission that constitutes a significant background contamination, renders such data insufficient to advance exospheric science beyond current understanding. Here, we describe a new nano-satellite mission concept for exospheric H investigation that overcomes these historical measurement limitations. The mission, known as the Tomographic Hydrogen Emission Observatory (THEO), is designed to provide 3-D photometric measurements of terrestrial H Lyman alpha emission from a highly autonomous, three-axis-stabilized, 6U CubeSat platform along a trans-lunar trajectory that is ideal for the unambiguous estimation of H density from the exobase to the magnetopause and beyond. In particular, we will describe the feasibility of meeting operational challenges associated with satellite navigation and communication at such large distances.

  5. Error Estimates for Emission Lines in the Hydrogen and Helium Isosequences

    NASA Astrophysics Data System (ADS)

    Smith, R. K.; Brickhouse, N. S.

    2000-05-01

    Emission lines from hydrogen and helium isosequence are among the strongest in X-ray spectra; they will soon be used to measure the temperature, density, and equilibrium state of collisionally excited, astrophysical plasmas. We have created a new plasma code, APEC, which calculates the emission from such a plasma. APEC calculates the line emission from the direct electron and proton excitation rate and the radiative and dielectronic recombination rate. We show how different collisional plasma codes give varying emissivities for some strong lines of O VII and Fe XXVI, where direct excitation is the primary effect. This variation is partly due to simple differences in the plasma code. However, the primary reason is that much work remains to be done on experimental and theoretical calculations of the atomic rates. Large (~ 50%) differences exist even for excitation rates for hydrogenic ions.

  6. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  7. Effect of hydrogen injection stability and emissions of an experimental premixed prevaporized propane burner

    NASA Technical Reports Server (NTRS)

    Anderson, D. N.

    1975-01-01

    Hydrogen in quantities up to 5 percent by weight of the total fuel flow was injected into a premixed propane burner. The hydrogen was either premixed with the propane and air upstream of the burner or introduced as a torch at the flameholder. Emissions of total nitrogen oxides, carbon monoxide, and unburned hydrocarbon are reported as are combustion efficiencies and lean blowout limits. To maintain at least 99 percent combustion efficiency at a 700 K inlet mixture temperature with no hydrogen added, it was necessary to burn with a propane equivalence ratio of 0.525. When 4 percent hydrogen was premixed with the propane and air, a combustion efficiency greater than 99 percent was recorded at a propane equivalence ratio of 0.425. The total nitrogen oxides (NOx) emissions corresponding to these two conditions were 0.8 g NO2/kg equivalent propane and 0.44 g NO2/kg equivalent propane, respectively. The hydrogen torch did not reduce NOx emissions.

  8. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  9. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  10. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  11. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  12. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  13. Emissions and Total Energy Consumption of a Multicylinder Piston Engine Running on Gasoline and a Hydrogen-gasoline Mixture

    NASA Technical Reports Server (NTRS)

    Cassidy, J. F.

    1977-01-01

    A multicylinder reciprocating engine was used to extend the efficient lean operating range of gasoline by adding hydrogen. Both bottled hydrogen and hydrogen produced by a research methanol steam reformer were used. These results were compared with results for all gasoline. A high-compression-ratio, displacement production engine was used. Apparent flame speed was used to describe the differences in emissions and performance. Therefore, engine emissions and performance, including apparent flame speed and energy lost to the cooling system and the exhaust gas, were measured over a range of equivalence ratios for each fuel. All emission levels decreased at the leaner conditions. Adding hydrogen significantly increased flame speed over all equivalence ratios.

  14. Hydrogen sulfide and nonmethane hydrocarbon emissions from broiler houses in the Southeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrogen sulfide (H2S) and nonmethane hydrocarbon (NMHC) emissions from two mechanically ventilated commercial broiler houses located in the Southeastern United States were continuously monitored over 12 flocks during the one-year period of 2006-2007 as a joint effort between Iowa State University a...

  15. Ultraviolet-pumped infrared fluorescent molecular hydrogen emission in reflection nebulae

    NASA Technical Reports Server (NTRS)

    Sellgren, K.

    1986-01-01

    Strong molecular hydrogen emission at 2.41 microns has been observed in three out of six reflection nebulae surveyed. A spectrum of one nebula, Parsamyan 18, shows several H2 lines whose intensity ratios have values agreeing with those predicted if the excitation is due to UV-pumped fluoresence and disagreeing with those predicted for shock and X-ray excitations.

  16. Impact of Increased Use of Hydrogen on Petroleum Consumption and Carbon Dioxide Emissions, The

    EIA Publications

    2008-01-01

    This report responds to a request from Senator Byron L. Dorgan for an analysis of the impacts on U.S. energy import dependence and emission reductions resulting from the commercialization of advanced hydrogen and fuel cell technologies in the transportation and distributed generation markets.

  17. Ammonia, hydrogen sulfide, carbon dioxide and particulate matter emissions from California high-rise layer houses

    NASA Astrophysics Data System (ADS)

    Lin, X.-J.; Cortus, E. L.; Zhang, R.; Jiang, S.; Heber, A. J.

    2012-01-01

    Ammonia and hydrogen sulfide are hazardous substances that are regulated by the U.S. Environmental Protection Agency through community right-to-know legislation (EPCRA, EPA, 2011). The emissions of ammonia and hydrogen sulfide from large commercial layer facilities are of concern to legislators and nearby neighbors. Particulate matter (PM 10 and PM 2.5) released from layer houses are two of seven criteria pollutants for which EPA has set National Ambient Air Quality Standards as required by the Clean Air Act. Therefore, it is important to quantify the baseline emissions of these pollutants. The emissions of ammonia, hydrogen sulfide, carbon dioxide and PM from two California high-rise layer houses were monitored for two years from October 2007 to October 2009. Each house had 32,500 caged laying hens. The monitoring site was setup in compliance with a U.S. EPA-approved quality assurance project plan. The results showed the average daily mean emission rates of ammonia, hydrogen sulfide and carbon dioxide were 0.95 ± 0.67 (standard deviation) g d -1 bird -1, 1.27 ± 0.78 mg d -1 bird -1 and 91.4 ± 16.5 g d -1 bird -1, respectively. The average daily mean emission rates of PM 2.5, PM 10 and total suspended particulate (TSP) were 5.9 ± 12.6, 33.4 ± 27.4, and 78.0 ± 42.7 mg d -1 bird -1, respectively. It was observed that ammonia emission rates in summer were lower than in winter because the high airflow stabilized the manure by drying it. The reductions due to lower moisture content were greater than the increases due to higher temperature. However, PM 10 emission rates in summer were higher than in winter because the drier conditions coupled with higher internal air velocities increased PM 10 release from feathers, feed and manure.

  18. Time-resolved spectroscopy measurements of hydrogen-alpha, -beta, and -gamma emissions

    SciTech Connect

    Parigger, Christian G.; Dackman, Matthew; Hornkohl, James O

    2008-11-01

    Hydrogen emission spectroscopy results are reported following laser-induced optical breakdown with infrared Nd:YAG laser radiation focused into a pulsed methane flow. Measurements of Stark-broadened atomic hydrogen-alpha, -beta, and -gamma lines show electron number densities of 0.3 to 4x10{sup 17} cm{sup -3} for time delays of 2.1 to 0.4 {mu}s after laser-induced optical breakdown. In methane flow, recombination molecular spectra of the {delta}{nu}=+2 progression of the C2 Swan system are discernable in the H{beta} and H{gamma} plasma emissions within the first few microseconds. The recorded atomic spectra indicate the occurrence of hydrogen self-absorption for pulsed CH4 flow pressures of 2.7x10{sup 5} Pa (25 psig) and 6.5x10{sup 5} Pa (80 psig)

  19. Time-resolved spectroscopy measurements of hydrogen-alpha, -beta, and -gamma emissions.

    PubMed

    Parigger, Christian G; Dackman, Matthew; Hornkohl, James O

    2008-11-01

    Hydrogen emission spectroscopy results are reported following laser-induced optical breakdown with infrared Nd:YAG laser radiation focused into a pulsed methane flow. Measurements of Stark-broadened atomic hydrogen-alpha, -beta, and -gamma lines show electron number densities of 0.3 to 4x10(17) cm(-3) for time delays of 2.1 to 0.4 micros after laser-induced optical breakdown. In methane flow, recombination molecular spectra of the Delta nu = +2 progression of the C(2) Swan system are discernable in the H(beta) and H(gamma) plasma emissions within the first few microseconds. The recorded atomic spectra indicate the occurrence of hydrogen self-absorption for pulsed CH(4) flow pressures of 2.7x10(5) Pa (25 psig) and 6.5x10(5) Pa (80 psig). PMID:19122690

  20. Tracing ram-pressure stripping with warm molecular hydrogen emission

    SciTech Connect

    Sivanandam, Suresh; Rieke, Marcia J.; Rieke, George H.

    2014-12-01

    We use the Spitzer Infrared Spectrograph to study four infalling cluster galaxies with signatures of ongoing ram-pressure stripping. H{sub 2} emission is detected in all four, and two show extraplanar H{sub 2} emission. The emission usually has a warm (T ∼ 115-160 K) and a hot (T ∼ 400-600 K) component that is approximately two orders of magnitude less massive than the warm one. The warm component column densities are typically 10{sup 19} to 10{sup 20} cm{sup –2} with masses of 10{sup 6} to 10{sup 8} M {sub ☉}. The warm H{sub 2} is anomalously bright compared with normal star-forming galaxies and therefore may be excited by ram-pressure. In the case of CGCG 97-073, the H{sub 2} is offset from the majority of star formation along the direction of the galaxy's motion in the cluster, suggesting that it is forming in the ram-pressure wake of the galaxy. Another galaxy, NGC 4522, exhibits a warm H{sub 2} tail approximately 4 kpc in length. These results support the hypothesis that H{sub 2} within these galaxies is shock-heated from the interaction with the intracluster medium. Stripping of dust is also a common feature of the galaxies. For NGC 4522, where the distribution of dust at 8 μm is well resolved, knots and ripples demonstrate the turbulent nature of the stripping process. The Hα and 24 μm luminosities show that most of the galaxies have star-formation rates comparable to similar mass counterparts in the field. Finally, we suggest a possible evolutionary sequence primarily related to the strength of ram-pressure that a galaxy experiences to explain the varied results observed in our sample.

  1. Tracing Ram-pressure Stripping with Warm Molecular Hydrogen Emission

    NASA Astrophysics Data System (ADS)

    Sivanandam, Suresh; Rieke, Marcia J.; Rieke, George H.

    2014-12-01

    We use the Spitzer Infrared Spectrograph to study four infalling cluster galaxies with signatures of ongoing ram-pressure stripping. H2 emission is detected in all four, and two show extraplanar H2 emission. The emission usually has a warm (T ~ 115-160 K) and a hot (T ~ 400-600 K) component that is approximately two orders of magnitude less massive than the warm one. The warm component column densities are typically 1019 to 1020 cm-2 with masses of 106 to 108 M ⊙. The warm H2 is anomalously bright compared with normal star-forming galaxies and therefore may be excited by ram-pressure. In the case of CGCG 97-073, the H2 is offset from the majority of star formation along the direction of the galaxy's motion in the cluster, suggesting that it is forming in the ram-pressure wake of the galaxy. Another galaxy, NGC 4522, exhibits a warm H2 tail approximately 4 kpc in length. These results support the hypothesis that H2 within these galaxies is shock-heated from the interaction with the intracluster medium. Stripping of dust is also a common feature of the galaxies. For NGC 4522, where the distribution of dust at 8 μm is well resolved, knots and ripples demonstrate the turbulent nature of the stripping process. The Hα and 24 μm luminosities show that most of the galaxies have star-formation rates comparable to similar mass counterparts in the field. Finally, we suggest a possible evolutionary sequence primarily related to the strength of ram-pressure that a galaxy experiences to explain the varied results observed in our sample.

  2. Hydrogen alpha laser ablation plasma diagnostics.

    PubMed

    Parigger, C G; Surmick, D M; Gautam, G; El Sherbini, A M

    2015-08-01

    Spectral measurements of the H(α) Balmer series line and the continuum radiation are applied to draw inferences of electron density, temperature, and the level of self-absorption in laser ablation of a solid ice target in ambient air. Electron densities of 17 to 3.2×10(24) m(-3) are determined from absolute calibrated emission coefficients for time delays of 100-650 ns after generation of laser plasma using Q-switched Nd:YAG radiation. The corresponding temperatures of 4.5-0.95 eV were evaluated from the absolute spectral radiance of the continuum at the longer wavelengths. The redshifted, Stark-broadened hydrogen alpha line emerges from the continuum radiation after a time delay of 300 ns. The electron densities inferred from power law formulas agree with the values obtained from the plasma emission coefficients. PMID:26258326

  3. Voyager measurements of hydrogen Lyman-α diffuse emission from the Milky Way.

    PubMed

    Lallement, Rosine; Quémerais, Eric; Bertaux, Jean-Loup; Sandel, Bill R; Izmodenov, Vlad

    2011-12-23

    Doppler-shifted hydrogen Lyman-alpha (Lyα) emission from galaxies is currently measured and used in cosmology as an indicator of star formation. Until now, the Milky Way emission has not been detected, owing to far brighter local sources, including the H (hydrogen) glow, i.e., solar Lyα radiation backscattered by interstellar atoms that flow within the solar system. Because observations from the Voyager spacecraft, now leaving the heliosphere, are decreasingly affected by the H glow, the ultraviolet spectrographs are detecting Lyα diffuse emission from our Galaxy. The surface brightness toward nearby star-forming regions is about 3 to 4 rayleighs. The escape fraction of the radiation from the brightest H II regions is on the order of 3% and is highly spatially variable. These results will help in constraining models of Lyα radiation transfer in distant galaxies. PMID:22144462

  4. Voyager Measurements of Hydrogen Lyman-α Diffuse Emission from the Milky Way

    NASA Astrophysics Data System (ADS)

    Lallement, Rosine; Quémerais, Eric; Bertaux, Jean-Loup; Sandel, Bill R.; Izmodenov, Vlad

    2011-12-01

    Doppler-shifted hydrogen Lyman-alpha (Lyα) emission from galaxies is currently measured and used in cosmology as an indicator of star formation. Until now, the Milky Way emission has not been detected, owing to far brighter local sources, including the H (hydrogen) glow, i.e., solar Lyα radiation backscattered by interstellar atoms that flow within the solar system. Because observations from the Voyager spacecraft, now leaving the heliosphere, are decreasingly affected by the H glow, the ultraviolet spectrographs are detecting Lyα diffuse emission from our Galaxy. The surface brightness toward nearby star-forming regions is about 3 to 4 rayleighs. The escape fraction of the radiation from the brightest H II regions is on the order of 3% and is highly spatially variable. These results will help in constraining models of Lyα radiation transfer in distant galaxies.

  5. Emissions of hydrogen cyanide from on-road gasoline and diesel vehicles

    NASA Astrophysics Data System (ADS)

    Moussa, Samar G.; Leithead, Amy; Li, Shao-Meng; Chan, Tak W.; Wentzell, Jeremy J. B.; Stroud, Craig; Zhang, Junhua; Lee, Patrick; Lu, Gang; Brook, Jeffery R.; Hayden, Katherine; Narayan, Julie; Liggio, John

    2016-04-01

    Hydrogen cyanide (HCN) is considered a marker for biomass burning emissions and is a component of vehicle exhaust. Despite its potential health impacts, vehicular HCN emissions estimates and their contribution to regional budgets are highly uncertain. In the current study, Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) was used to measure HCN emission factors from the exhaust of individual diesel, biodiesel and gasoline vehicles. Laboratory emissions data as a function of fuel type and driving mode were combined with ambient measurement data and model predictions. The results indicate that gasoline vehicles have the highest emissions of HCN (relative to diesel fuel) and that biodiesel fuel has the potential to significantly reduce HCN emissions even at realistic 5% blend levels. The data further demonstrate that gasoline direct injection (GDI) engines emit more HCN than their port fuel injection (PFI) counterparts, suggesting that the expected full transition of vehicle fleets to GDI will increase HCN emissions. Ambient measurements of HCN in a traffic dominated area of Toronto, Canada were strongly correlated to vehicle emission markers and consistent with regional air quality model predictions of ambient air HCN, indicating that vehicle emissions of HCN are the dominant source of exposure in urban areas. The results further indicate that additional work is required to quantify HCN emissions from the modern vehicle fleet, particularly in light of continuously changing engine, fuel and after-treatment technologies.

  6. Hydrogen production and delivery analysis in US markets : cost, energy and greenhouse gas emissions.

    SciTech Connect

    Mintz, M.; Gillette, J.; Elgowainy, A.

    2009-01-01

    Hydrogen production cost conclusions are: (1) Steam Methane Reforming (SMR) is the least-cost production option at current natural gas prices and for initial hydrogen vehicle penetration rates, at high production rates, SMR may not be the least-cost option; (2) Unlike coal and nuclear technologies, the cost of natural gas feedstock is the largest contributor to SMR production cost; (3) Coal- and nuclear-based hydrogen production have significant penalties at small production rates (and benefits at large rates); (4) Nuclear production of hydrogen is likely to have large economies of scale, but because fixed O&M costs are uncertain, the magnitude of these effects may be understated; and (5) Given H2A default assumptions for fuel prices, process efficiencies and labor costs, nuclear-based hydrogen is likely to be more expensive to produce than coal-based hydrogen. Carbon taxes and caps can narrow the gap. Hydrogen delivery cost conclusions are: (1) For smaller urban markets, compressed gas delivery appears most economic, although cost inputs for high-pressure gas trucks are uncertain; (2) For larger urban markets, pipeline delivery is least costly; (3) Distance from hydrogen production plant to city gate may change relative costs (all results shown assume 100 km); (4) Pipeline costs may be reduced with system 'rationalization', primarily reductions in service pipeline mileage; and (5) Liquefier and pipeline capital costs are a hurdle, particularly at small market sizes. Some energy and greenhouse gas Observations: (1) Energy use (per kg of H2) declines slightly with increasing production or delivery rate for most components (unless energy efficiency varies appreciably with scale, e.g., liquefaction); (2) Energy use is a strong function of production technology and delivery mode; (3) GHG emissions reflect the energy efficiency and carbon content of each component in a production-delivery pathway; (4) Coal and natural gas production pathways have high energy consumption

  7. Stratospheric cooling and polar ozone loss due to H2 emissions of a global hydrogen economy

    NASA Astrophysics Data System (ADS)

    Feck, T.; Grooß, J.-U.; Riese, M.; Vogel, B.

    2009-04-01

    "Green" hydrogen is seen as a major element of the future energy supply to reduce greenhouse gas emissions substantially. However, due to the possible interactions of hydrogen (H2) with other atmospheric constituents there is a need to analyse the implications of additional atmospheric H2 that could result from hydrogen leakage of a global hydrogen infrastructure. Emissions of molecular H2 can occur along the whole hydrogen process chain which increase the tropospheric H2 burden. Across the tropical tropopause H2 reaches the stratosphere where it is oxidised and forms water vapour (H2O). This causes increased IR-emissions into space and hence a cooling of the stratosphere. Both effects, the increase of stratospheric H2O and the cooling, enhances the potential of chlorine activation on liquid sulfate aerosol and polar stratospheric clouds (PSCs), which increase polar ozone destruction. Hence a global hydrogen economy could provoke polar ozone loss and could lead to a substantial delay of the current projected recovery of the stratospheric ozone layer. Our investigations show that even if 90% of the current global fossil primary energy input could be replaced by hydrogen and approximately 9.5% of the product gas would leak to the atmosphere, the ozone loss would be increased between 15 to 26 Dobson Units (DU) if the stratospheric CFC loading would retain unchanged. A consistency check of the used approximation methods with the Chemical Lagrangian Model of the Stratosphere (CLaMS) shows that this additional ozone loss can probably be treated as an upper limit. Towards more realistic future H2 leakage rate assumptions (< 3%) the additional ozone loss would be rather small (? 10 DU). However, in all cases the full damage would only occur if stratospheric CFC-levels would retain unchanged. Due to the CFC-prohibition as a result of the Montreal Protocol the forecasts suggest a decline of the stratospheric CFC loading about 50% until 2050. In this case our calculations

  8. Optical emission spectroscopy for simultaneous measurement of plasma electron density and temperature in a low-pressure microwave induced plasma

    SciTech Connect

    Konjevic, N.; Jovicevic, S.; Ivkovic, M.

    2009-10-15

    The simple optical emission spectroscopy technique for diagnostics of low pressure microwave induced plasma (MIP) in hydrogen or in MIP seeded with hydrogen is described and tested. This technique uses the Boltzmann plot of relative line intensities along Balmer spectral series in conjunction with the criterion for partial local thermodynamic equilibrium for low electron density (N{sub e}) plasma diagnostics. The proposed technique is tested in a low pressure MIP discharge for simultaneous determination of electron density N{sub e} (10{sup 17}-10{sup 18} m{sup -3}) and temperature T{sub e}.

  9. Micro-Mixing Lean-Premix System for Ultra-Low Emission Hydrogen/Syngas Combustion

    SciTech Connect

    Erlendur Steinthorsson; Brian Hollon; Adel Mansour

    2010-06-30

    The focus of this project was to develop the next generation of fuel injection technologies for environmentally friendly, hydrogen syngas combustion in gas turbine engines that satisfy DOE's objectives of reducing NOx emissions to 3 ppm. Building on Parker Hannifin's proven Macrolamination technology for liquid fuels, Parker developed a scalable high-performing multi-point injector that utilizes multiple, small mixing cups in place of a single conventional large-scale premixer. Due to the small size, fuel and air mix rapidly within the cups, providing a well-premixed fuel-air mixture at the cup exit in a short time. Detailed studies and experimentation with single-cup micro-mixing injectors were conducted to elucidate the effects of various injector design attributes and operating conditions on combustion efficiency, lean stability and emissions and strategies were developed to mitigate the impact of flashback. In the final phase of the program, a full-scale 1.3-MWth multi-cup injector was built and tested at pressures from 6.9bar (100psi) to 12.4bar (180psi) and flame temperatures up to 2000K (3150 F) using mixtures of hydrogen and natural gas as fuel with nitrogen and carbon dioxide as diluents. The injector operated without flash back on fuel mixtures ranging from 100% natural gas to 100% hydrogen and emissions were shown to be insensitive to combustor pressure. NOx emissions of 3-ppm were achieved at a flame temperature of 1750K (2690 F) when operating on a fuel mixture containing 50% hydrogen and 50% natural gas by volume with 40% nitrogen dilution and 1.5-ppm NOx was achieved at a flame temperature of 1680K (2564 F) using only 10% nitrogen dilution. NOx emissions of 3.5-ppm were demonstrated at a flame temperature of 1730K (2650 F) with only 10% carbon dioxide dilution. Finally, 3.6-ppm NOx emissions were demonstrated at a flame temperature over 1600K (2420 F) when operating on 100% hydrogen fuel with 30% carbon dioxide dilution. Superior operability was

  10. New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation

    NASA Astrophysics Data System (ADS)

    Kowalski, Adam F.; Hawley, S. L.; Carlsson, M.; Allred, J. C.; Uitenbroek, H.; Osten, R. A.; Holman, G.

    2015-12-01

    The heating mechanism at high densities during M-dwarf flares is poorly understood. Spectra of M-dwarf flares in the optical and near-ultraviolet wavelength regimes have revealed three continuum components during the impulsive phase: 1) an energetically dominant blackbody component with a color temperature of T≈104 K in the blue-optical, 2) a smaller amount of Balmer continuum emission in the near-ultraviolet at λ≤3 646 Å, and 3) an apparent pseudo-continuum of blended high-order Balmer lines between λ=3 646 Å and λ≈3 900 Å. These properties are not reproduced by models that employ a typical "solar-type" flare heating level of ≤ 10^{11} erg cm^{-2} s^{-1} in nonthermal electrons, and therefore our understanding of these spectra is limited to a phenomenological three-component interpretation. We present a new 1D radiative-hydrodynamic model of an M-dwarf flare from precipitating nonthermal electrons with a high energy flux of 10^{13} erg cm^{-2} s^{-1}. The simulation produces bright near-ultraviolet and optical continuum emission from a dense (n>10^{15} cm^{-3}), hot (T ≈12 000 - 13 500 K) chromospheric condensation. For the first time, the observed color temperature and Balmer jump ratio are produced self-consistently in a radiative-hydrodynamic flare model. We find that a T≈104 K blackbody-like continuum component and a low Balmer jump ratio result from optically thick Balmer (∞→ n=2) and Paschen recombination (∞→ n=3) radiation, and thus the properties of the flux spectrum are caused by blue (λ≈4 300 Å) light escaping over a larger physical depth range than by red (λ≈6 700 Å) and near-ultraviolet (λ≈3 500 Å) light. To model the near-ultraviolet pseudo-continuum previously attributed to overlapping Balmer lines, we include the extra Balmer continuum opacity from Landau-Zener transitions that result from merged, high-order energy levels of hydrogen in a dense, partially ionized atmosphere. This reveals a new diagnostic of

  11. Effects of Coaxial Air on Nitrogen-Diluted Hydrogen Jet Diffusion Flame Length and NOx Emission

    SciTech Connect

    Weiland, N.T.; Chen, R.-H.; Strakey, P.A.

    2007-10-01

    Turbulent nitrogen-diluted hydrogen jet diffusion flames with high velocity coaxial air flows are investigated for their NOx emission levels. This study is motivated by the DOE turbine program’s goal of achieving 2 ppm dry low NOx from turbine combustors running on nitrogen-diluted high-hydrogen fuels. In this study, effects of coaxial air velocity and momentum are varied while maintaining low overall equivalence ratios to eliminate the effects of recirculation of combustion products on flame lengths, flame temperatures, and resulting NOx emission levels. The nature of flame length and NOx emission scaling relationships are found to vary, depending on whether the combined fuel and coaxial air jet is fuel-rich or fuel-lean. In the absence of differential diffusion effects, flame lengths agree well with predicted trends, and NOx emissions levels are shown to decrease with increasing coaxial air velocity, as expected. Normalizing the NOx emission index with a flame residence time reveals some interesting trends, and indicates that a global flame strain based on the difference between the fuel and coaxial air velocities, as is traditionally used, is not a viable parameter for scaling the normalized NOx emissions of coaxial air jet diffusion flames.

  12. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  13. Hydrogen Pathways: Updated Cost, Well-to-Wheels Energy Use, and Emissions for the Current Technology Status of Ten Hydrogen Production, Delivery, and Distribution Scenarios

    SciTech Connect

    Ramsden, T.; Ruth, M.; Diakov, V.; Laffen, M.; Timbario, T. A.

    2013-03-01

    This report describes a life-cycle assessment conducted by the National Renewable Energy Laboratory (NREL) of 10 hydrogen production, delivery, dispensing, and use pathways that were evaluated for cost, energy use, and greenhouse gas (GHG) emissions. This evaluation updates and expands on a previous assessment of seven pathways conducted in 2009. This study summarizes key results, parameters, and sensitivities to those parameters for the 10 hydrogen pathways, reporting on the levelized cost of hydrogen in 2007 U.S. dollars as well as life-cycle well-to-wheels energy use and GHG emissions associated with the pathways.

  14. Mid Infrared Hydrogen Recombination Line Emission from the Maser Star MWC 349A

    NASA Technical Reports Server (NTRS)

    Smith, Howard A.; Strelnitski, V.; Miles, J. W.; Kelly, D. M.; Lacy, J. H.

    1997-01-01

    We have detected and spectrally resolved the mid-IR hydrogen recombination lines H6(alpha)(12.372 micrometers), H7(alpha)(19.062 micrometers), H7(beta)(l1.309 micrometers) and H8(gamma)(12.385 micrometers) from the star MWC349A. This object has strong hydrogen maser emission (reported in the millimeter and submillimeter hydrogen recombination lines from H36(alpha) to H21(alpha)) and laser emission (reported in the H15(alpha), H12(alpha) and H10(alpha) lines). The lasers/masers are thought to arise predominantly in a Keplerian disk around the star. The mid-IR lines do not show evident signs of lasing, and can be well modeled as arising from the strong stellar wind, with a component arising from a quasi-static atmosphere around the disk, similar to what is hypothesized for the near IR (less than or equal to 4 micrometers) recombination lines. Since populations inversions in the levels producing these mid-IR transitions are expected at densities up to approximately 10(exp 11)/cu cm, these results imply either that the disk does not contain high-density ionized gas over long enough path lengths to produce a gain approximately 1, and/or that any laser emission from such regions is small compared to the spontaneous background emission from the rest of the source as observed with a large beam. The results reinforce the interpretation of the far-IR lines as true lasers.

  15. Hydrogen production rates from ground-based Fabry-Perot observations of comet Kohoutek

    NASA Technical Reports Server (NTRS)

    Scherb, F.

    1981-01-01

    The only ground-based observations of a cometary hydrogen corona that have been obtained up to the present were carried out during the appearance of comet Kohoutek (1973 XII). Hydrogen Balmer alpha (H-alpha) emission from the gas cloud surrounding the comet was detected using a Fabry-Perot spectrometer at Kitt Peak National Observatory. These observations have been reexamined using (1) recently obtained solar full-disk Lyman beta emission line profiles, (2) a new calibration of the absolute sensitivity of the Fabry-Perot spectrometer based on comparison of NGC 7000 with standard stars and the planetary nebula NGC 7662, and (3) corrections for atmospheric extinction instead of the geocoronal H-alpha comparison method used previously to obtain comet H-alpha intensities. The new values for hydrogen production rates are in good agreement with results obtained from Lyman alpha observations of comet Kohoutek.

  16. Evolution of Balmer jump selected galaxies in the ALHAMBRA survey

    NASA Astrophysics Data System (ADS)

    Troncoso Iribarren, P.; Infante, L.; Padilla, N.; Lacerna, I.; Garcia, S.; Orsi, A.; Muñoz Arancibia, A.; Moustakas, J.; Cristóbal-Hornillos, D.; Moles, M.; Fernández-Soto, A.; Martínez, V. J.; Cerviño, M.; Alfaro, E. J.; Ascaso, B.; Arnalte-Mur, P.; Nieves-Seoane, L.; Benítez, N.

    2016-04-01

    Context. Samples of star-forming galaxies at different redshifts have been traditionally selected via color techniques. The ALHAMBRA survey was designed to perform a uniform cosmic tomography of the Universe, and we here exploit it to trace the evolution of these galaxies. Aims: Our objective is to use the homogeneous optical coverage of the ALHAMBRA filter system to select samples of star-forming galaxies at different epochs of the Universe and study their properties. Methods: We present a new color-selection technique, based on the models of spectral evolution convolved with the ALHAMBRA bands and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 Balmer-jump Galaxies (BJGs). We applied the iSEDfit Bayesian approach to fit each detailed spectral energy distribution and determined star-formation rate (SFR), stellar mass, age, and absolute magnitudes. The mass of the halos in which these samples reside were found through a clustering analysis. Results: Five volume-limited BJG subsamples with different mean redshifts are found to reside in halos of median masses ~1012.5 ± 0.2 M⊙ slightly increasing toward z = 0.5. This increment is similar to numerical simulations results, which suggests that we trace the evolution of an evolving population of halos as they grow to reach a mass of ~1012.7 ± 0.1 at z = 0.5. The likely progenitors of our samples at z ~ 3 are Lyman-break galaxies, which at z ~ 2 would evolve into star-forming BzK galaxies, and their descendants in the local Universe are galaxies with luminosities of 1-3 L∗. Hence, this allows us to follow the putative evolution of the SFR, stellar mass, and age of these galaxies. Conclusions: From z ~ 1.0 to z ~ 0.5, the stellar mass of the volume-limited BJG samples changes almost not at all with redshift, suggesting that major mergers play a minor role in the evolution of these galaxies. The SFR evolution accounts for the small

  17. Emissions of molecular hydrogen (H2) and its isotopic signature from residential heaters and waste incinerators

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Mohn, J.; Steinbacher, M.; Bond, S. W.; Roeckmann, T.; Reimann, S.

    2011-12-01

    Atmospheric molecular hydrogen (H2) has recently received increased interest in the scientific community because of a potential shift to a global hydrogen energy economy which could potentially alter the atmospheric budget of H2 due to substantial leakage. This calls for an improved understanding of the present day's atmospheric H2 budget. One of the major sources of H2 are emissions from incomplete combustion of fossil fuel. While emissions of H2 from car exhaust have been studied extensively, those from fossil fuel based heating systems have remained a matter of speculation. Here we present results from measurements of a variety of residential heating systems covering oil, gas, and wood heating with various burner capacities. For oil and gas heating systems we surprisingly find no net H2 emissions, i.e. the exhaust air contains H2 at or below the mole fractions of the intake air (approx. 0.5 ppm). While H2 emissions are virtually absent, those of carbon monoxide (CO) are not. As a consequence, caution has to be exercised when modeling H2 emissions based on assumed H2/CO ratios and using CO emission inventories. We also find that the molecular hydrogen in the approx. 0.5 ppm exhaust air is isotopically strongly depleted (-20 permil to -200 permil) compared to the ambient air (+130 permil). This suggests that H2 is involved in the combustion processes, and therefore the H2 of the intake air is not the same H2 in the exhaust air. Exhausts from waste incinerator plants are generally also depleted in H2 mole fractions and in their H/D isotopic composition.

  18. Infrared emission from hydrogenated amorphous carbon and amorphous carbon grains in the interstellar medium

    NASA Technical Reports Server (NTRS)

    Duley, W. W.; Jones, A. P.; Taylor, S. D.; Williams, D. A.

    1993-01-01

    The correlations deduced by Boulanger et al. (1990) from IRAS maps of the Chamaeleon, Taurus and Ursa Major molecular cloud complexes are interpreted in terms of the evolutionary hydrogenated amorphous carbon model of interstellar dust. In particular, regions of relatively strong 12-micron emission may be regions where recently accreted carbon is being converted by ambient UV to small PAHs in situ. Regions of weak 12-micron emission are probably quiescent regions where carbon has been annealed to amorphous carbon. Observational consequences of these inferences are briefly described.

  19. An interpretation of Mariner 10 helium /584 A/ and hydrogen /1216 A/ interplanetary emission observations

    NASA Technical Reports Server (NTRS)

    Ajello, J. M.

    1978-01-01

    Measurements of the interplanetary emissions of both He(584 A) and H(1216 A) on January 28, 1974, a time of solar minimum, are reported and discussed. An analysis of the Mariner 10 ultraviolet spectrometer data shows that a simultaneous measurement of both emissions results in a self-consistent determination of the physical properties of the interstellar wind. With the aid of a model the number densities of helium and hydrogen outside the solar system were found to be 0.008 + or - 0.003/cu cm and 0.04 (+0.03, -0.02)/cu cm, respectively, which indicates a He/H ratio of 0.20 (+0.30, -0.13). Values characterizing the helium cone, interstellar wind temperature, effective lifetime of hydrogen atoms in the solar system, and downstream direction of the interstellar wind are presented.

  20. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In front of the Headquarters Building at KSC, Center Director Roy Bridges (left) looks at the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by- product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  1. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    KSC employees, along with Center Director Roy Bridges (second from left), view the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  2. Photoelectron emission from metal surfaces induced by VUV-emission of filament driven hydrogen arc discharge plasma

    SciTech Connect

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

    2015-04-08

    Photoelectron emission measurements have been performed using a filament-driven multi-cusp arc discharge volume production H{sup −} ion source (LIISA). It has been found that photoelectron currents obtained with Al, Cu, Mo, Ta and stainless steel (SAE 304) are on the same order of magnitude. The photoelectron currents depend linearly on the discharge power. It is shown experimentally that photoelectron emission is significant only in the short wavelength range of hydrogen spectrum due to the energy dependence of the quantum efficiency. It is estimated from the measured data that the maximum photoelectron flux from plasma chamber walls is on the order of 1 A per kW of discharge power.

  3. Europa - Ultraviolet emissions and the possibility of atomic oxygen and hydrogen clouds

    NASA Technical Reports Server (NTRS)

    Wu, F.-M.; Judge, D. L.; Carlson, R. W.

    1978-01-01

    Emission signals from Europa with wavelength below 800 A were detected by the Pioneer 10 ultraviolet photometer. In the present paper, improved procedures for data reduction are used to determine the spatial region as well as the intensity of the suggested emission sources. The observations indicate a cloud with a radius of about 1.5 Jupiter radii and an apparent brightness of approximately 10 rayleighs for a wavelength of 500 A. It is argued that neutral oxygen atoms, along with neutral hydrogen, are produced through dissociation of water ice on the surface of Europa by particle impact. Electron impact ionization excitation of oxygen atoms in the resulting cloud then gives rise to the observed emission. The present source brightness and cloud radius results are used to estimate an oxygen column density of the order of 10 trillion per sq cm, while the density of atomic hydrogen is at most 100 billion per sq cm and 1 trillion per sq cm for molecular hydrogen.

  4. Emission of hydrogen energetic neutral atoms from the Martian subsolar magnetosheath

    NASA Astrophysics Data System (ADS)

    Wang, X.-D.; Alho, M.; Jarvinen, R.; Kallio, E.; Barabash, S.; Futaana, Y.

    2016-01-01

    We have simulated the hydrogen energetic neutral atom (ENA) emissions from the subsolar magnetosheath of Mars using a hybrid model of the proton plasma charge exchanging with the Martian exosphere to study statistical features revealed from the observations of the Neutral Particle Detectors on Mars Express. The simulations reproduce well the observed enhancement of the hydrogen ENA emissions from the dayside magnetosheath in directions perpendicular to the Sun-Mars line. Our results show that the neutralized protons from the shocked solar wind are the dominant ENA population rather than those originating from the pickup planetary ions. The simulation also suggests that the observed stronger ENA emissions in the direction opposite to the solar wind convective electric field result from a stronger proton flux in the same direction at the lower magnetosheath; i.e., the proton fluxes in the magnetosheath are not cylindrically symmetric. We also confirm the observed increasing of the ENA fluxes with the solar wind dynamical pressure in the simulations. This feature is associated with a low altitude of the induced magnetic boundary when the dynamic pressure is high and the magnetosheath protons can reach to a denser exosphere, and thus, the charge exchange rate becomes higher. Overall, the analysis suggests that kinetic effects play an important and pronounced role in the morphology of the hydrogen ENA distribution and the plasma environment at Mars, in general.

  5. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    NASA Astrophysics Data System (ADS)

    Wang, Zi-han; Wang, Chun-mei; Tang, Hua-xin; Zuo, Cheng-ji; Xu, Hong-ming

    2009-06-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  6. An intensity map of hydrogen 21-cm emission at redshift z approximately 0.8.

    PubMed

    Chang, Tzu-Ching; Pen, Ue-Li; Bandura, Kevin; Peterson, Jeffrey B

    2010-07-22

    Observations of 21-cm radio emission by neutral hydrogen at redshifts z approximately 0.5 to approximately 2.5 are expected to provide a sensitive probe of cosmic dark energy. This is particularly true around the onset of acceleration at z approximately 1, where traditional optical cosmology becomes very difficult because of the infrared opacity of the atmosphere. Hitherto, 21-cm emission has been detected only to z = 0.24. More distant galaxies generally are too faint for individual detections but it is possible to measure the aggregate emission from many unresolved galaxies in the 'cosmic web'. Here we report a three-dimensional 21-cm intensity field at z = 0.53 to 1.12. We then co-add neutral-hydrogen (H i) emission from the volumes surrounding about 10,000 galaxies (from the DEEP2 optical galaxy redshift survey). We detect the aggregate 21-cm glow at a significance of approximately 4sigma. PMID:20651685

  7. Effect of primary-zone equivalence ratio and hydrogen addition on exhaust emission in a hydrocarbon-fueled combustor

    NASA Technical Reports Server (NTRS)

    Norgren, C. T.; Ingebo, R. D.

    1974-01-01

    The effects of reducing the primary-zone equivalence ratio on the exhaust emission levels of oxides of nitrogen, carbon monoxide, and unburned hydrocarbons in experimental hydrocarbon-fueled combustor segments at simulated supersonic cruise and idle conditions were investigated. In addition, the effects of the injection of hydrogen fuel (up to 4 percent of the total weight of fuel) on the stability of the hydrocarbon flame and exhaust emissions were studied and compared with results obtained without hydrogen addition.

  8. Emissions of oxides of nitrogen from an experimental premixed-hydrogen burner

    NASA Technical Reports Server (NTRS)

    Anderson, D. N.

    1976-01-01

    Flame-tube experiments using premixed hydrogen and air were conducted to determine the emissions of oxides of nitrogen (NOx) resulting from ultralean combustion. Measurements of NOx emissions and combustion efficiency were made for inlet mixture temperatures of 600 and 700 K, pressures of 3.8 x 10 to the 5th power and 5.2 x 10 to the 5th power N/m squared, reference velocities of 15 to 18 m/sec, and equivalence ratios of 0.2 to 0.4. At the 700 K inlet mixture temperature, NOx emissions were 0.06 ppmv, and combustion efficiency was 98 percent at an equivalence ratio of 0.24. The use of a high-blockage (92-percent blockage) flameholder made it possible to conduct tests without upstream burning in the premixing duct for mixtures with equivalence ratios less than 0.4. For richer mixtures upstream burning did occur and prevented further testing.

  9. Global emissions of hydrogen chloride and chloromethane from coal combustion, incineration and industrial activities: Reactive Chlorine Emissions Inventory

    NASA Astrophysics Data System (ADS)

    McCulloch, Archie; Aucott, Michael L.; Benkovitz, Carmen M.; Graedel, Thomas E.; Kleiman, Gary; Midgley, Pauline M.; Li, Yi-Fan

    1999-04-01

    Much if not all of the chlorine present in fossil fuels is released into the atmosphere as hydrogen chloride (HCl) and chloromethane (CH3Cl, methyl chloride). The chlorine content of oil-based fuels is so low that these sources can be neglected, but coal combustion provides significant releases. On the basis of national statistics for the quantity and quality of coal burned during 1990 in power and heat generation, industrial conversion and residential and commercial heating, coupled with information on the chlorine contents of coals, a global inventory of national HCl emissions from this source has been constructed. This was combined with an estimate of the national emissions of HCl from waste combustion (both large-scale incineration and trash burning) which was based on an estimate of the global quantity released from this source expressed per head of population. Account was taken of reduced emissions where flue gases were processed, for example to remove sulphur dioxide. The HCl emitted in 1990, comprising 4.6 ± 4.3 Tg Cl from fossil fuel and 2 ± 1.9 Tg Cl from waste burning, was spatially distributed using available information on point sources such as power generation utilities and population density by default. Also associated with these combustion sources are chloromethane emissions, calculated to be 0.075 ± 0.07 Tg as Cl (equivalent) from fossil fuels and 0.032 ± 0.023 Tg Cl (equivalent) from waste combustion. These were distributed spatially exactly as the HCl emissions, and a further 0.007 Tg Cl in chloromethane from industrial process activity was distributed by point sources.

  10. Effect of fuel nitrogen and hydrogen content on emissions in hydrocarbon combustion

    NASA Technical Reports Server (NTRS)

    Bittker, D. A.; Wolfbrandt, G.

    1981-01-01

    How the emissions of nitrogen oxides and carbon monoxide are affected by: (1) the decreased hydrogen content and (2) the increased organic nitrogen content of coal derived fuels is investigated. Previous CRT experimental work in a two stage flame tube has shown the effectiveness of rich lean two stage combustion in reducing fuel nitrogen conversion to nitrogen oxides. Previous theoretical work gave preliminary indications that emissions trends from the flame tube experiment could be predicted by a two stage, well stirred reactor combustor model using a detailed chemical mechanism for propane oxidation and nitrogen oxide formation. Additional computations are reported and comparisons with experimental results for two additional fuels and a wide range of operating conditions are given. Fuels used in the modeling are pure propane, a propane toluene mixture and pure toluene. These give hydrogen contents 18, 11 and 9 percent by weight, respectively. Fuel bound nitrogen contents of 0.5 and 1.0 percent were used. Results are presented for oxides of nitrogen and also carbon monoxide concentrations as a function of primary equivalence ratio, hydrogen content and fuel bound nitrogen content.

  11. The Effect of Converting to a U.S. Hydrogen Fuel Cell Vehicle Fleet on Emissions and Energy Use

    NASA Astrophysics Data System (ADS)

    Colella, W. G.; Jacobson, M. Z.; Golden, D. M.

    2004-12-01

    This study analyzes the potential change in emissions and energy use from replacing fossil-fuel based vehicles with hydrogen fuel cell vehicles. This study examines three different hydrogen production scenarios to determine their resultant emissions and energy usage: hydrogen produced via 1) steam reforming of methane, 2) coal gasification, or 3) wind electrolysis. The atmospheric model simulations require two primary sets of data: the actual emissions associated with hydrogen fuel production and use, and the corresponding reduction in emissions associated with reducing fossil fuel use. The net change in emissions is derived using 1) the U.S. EPA's National Emission Inventory (NEI) that incorporates several hundred categories of on-road vehicles and 2) a Process Chain Analysis (PCA) for the different hydrogen production scenarios. NEI: The quantity of hydrogen-related emission is ultimately a function of the projected hydrogen consumption in on-road vehicles. Data for hydrogen consumption from on-road vehicles was derived from the number of miles driven in each U.S. county based on 1999 NEI data, the average fleet mileage of all on-road vehicles, the average gasoline vehicle efficiency, and the efficiency of advanced 2004 fuel cell vehicles. PCA: PCA involves energy and mass balance calculations around the fuel extraction, production, transport, storage, and delivery processes. PCA was used to examine three different hydrogen production scenarios: In the first scenario, hydrogen is derived from natural gas, which is extracted from gas fields, stored, chemically processed, and transmitted through pipelines to distributed fuel processing units. The fuel processing units, situated in similar locations as gasoline refueling stations, convert natural gas to hydrogen via a combination of steam reforming and fuel oxidation. Purified hydrogen is compressed for use onboard fuel cell vehicles. In the second scenario, hydrogen is derived from coal, which is extracted from

  12. White-light emission from solid carbon in aqueous solution during hydrogen generation induced by nanosecond laser pulse irradiation

    NASA Astrophysics Data System (ADS)

    Akimoto, Ikuko; Yamamoto, Shota; Maeda, Kosuke

    2016-07-01

    We previously discovered a novel method of hydrogen generation from high-grade charcoal in an aqueous solution using nanosecond laser pulse irradiation. In this paper, white-light emission during this reaction is reported: A broad spectrum over the visible range is observed above a threshold excitation energy density. The white-light emission is a simultaneous product of the hydrogen generation reaction and is attributed to blackbody radiation in accordance with Planck's Law at a temperature above 3800 K. Consequently, we propose that hydrogen generation induced by laser irradiation proceeds similarly to classical coal gasification, which features reactions at high pressure and high temperature.

  13. Electron emission and molecular fragmentation during hydrogen and deuterium ion impact on carbon surfaces

    NASA Astrophysics Data System (ADS)

    Qayyum, A.; Schustereder, W.; Mair, C.; Scheier, P.; Märk, T. D.; Cernusca, S.; Winter, HP.; Aumayr, F.

    2003-03-01

    Molecular fragmentation and electron emission during hydrogen ion impact on graphite surfaces has been investigated in the eV to keV impact energy region typical for fusion edge plasma conditions. As a target surface graphite tiles for the Tokamak experiment Tore Supra in CEA-Cadarache/France and highly oriented pyrolytic graphite (HOPG) have been used. For both surfaces studied, the experimentally observed threshold for electron emission is at about 50 eV/amu impact energy. Electron emission from the high conductivity side of the carbon tile is 15-20% less as compared to its low conductivity side, whereas results for HOPG are generally between these two cases. Deuterium and hydrogen ions are almost equally effective in liberating electrons from graphite when comparing results for the same impact velocity. Surface-induced dissociation of deuterium ions D 3+ upon impact on Tore Supra graphite tiles, in the collision energy range of 20-100 eV, produced only atomic fragment ions D +. The other possible fragment ion D 2+ could not be observed.

  14. Combined borax and tannin treatment of stored dairy manure to reduce bacterial populations and hydrogen sulfide emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Anaerobic digestion of organic residues in stored livestock manure is associated with the production of odors and emissions. Hydrogen sulfide (H2S) is one such emission that can reach hazardous levels during manure storage and handling, posing a risk to both farmers and livestock. New te...

  15. Correlations between density distributions, optical spectra, and ion species in a hydrogen plasma (invited)

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Megía-Macías, A.; Tarvainen, O.; Kalvas, T.; Koivisto, H.

    2016-02-01

    An experimental study of plasma distributions in a 2.45 GHz hydrogen discharge operated at 100 Hz repetition rate is presented. Ultrafast photography, time integrated visible light emission spectra, time resolved Balmer-alpha emission, time resolved Fulcher Band emission, ion species mass spectra, and time resolved ion species fraction measurements have been implemented as diagnostic tools in a broad range of plasma conditions. Results of plasma distributions and optical emissions correlated with H+, H2 + , and H3 + ion currents by using a Wien filter system with optical observation capability are reported. The magnetic field distribution and strength is found as the most critical factor for transitions between different plasma patterns and ion populations.

  16. Correlations between density distributions, optical spectra, and ion species in a hydrogen plasma (invited).

    PubMed

    Cortázar, O D; Megía-Macías, A; Tarvainen, O; Kalvas, T; Koivisto, H

    2016-02-01

    An experimental study of plasma distributions in a 2.45 GHz hydrogen discharge operated at 100 Hz repetition rate is presented. Ultrafast photography, time integrated visible light emission spectra, time resolved Balmer-alpha emission, time resolved Fulcher Band emission, ion species mass spectra, and time resolved ion species fraction measurements have been implemented as diagnostic tools in a broad range of plasma conditions. Results of plasma distributions and optical emissions correlated with H(+), H2 (+), and H3 (+) ion currents by using a Wien filter system with optical observation capability are reported. The magnetic field distribution and strength is found as the most critical factor for transitions between different plasma patterns and ion populations. PMID:26931922

  17. Star formation activity in Balmer break galaxies at z< 1.5

    NASA Astrophysics Data System (ADS)

    Díaz Tello, J.; Donzelli, C.; Padilla, N.; Akiyama, M.; Fujishiro, N.; Yoshikawa, T.; Hanami, H.

    2016-03-01

    Aims: We present a spectroscopic study of the properties of 64 Balmer break galaxies that show signs of star formation. The studied sample of star-forming galaxies spans a redshift range from 0.094 to 1.475 with stellar masses in the range 108-1012M⊙. The sample also includes eight broad emission line galaxies with redshifts between 1.5 emission line luminosities and investigated the dependence of the SFR and specific SFR (SSFR) on the stellar mass and color. Furthermore, we investigated the evolution of these relations with the redshift. Results: We found that the SFR correlates with the stellar mass; our data is consistent with previous results from other authors in that there is a break in the correlation, which reveals the presence of massive galaxies with lower SFR values (i.e., decreasing star formation). We also note an anticorrelation for the SSFR with the stellar mass. Again in this case, our data is also consistent with a break in the correlation, revealing the presence of massive star-forming galaxies with lower SSFR values, thereby increasing the anticorrelation. These results might suggest a characteristic mass (M0) at which the red sequence could mostly be assembled. In addition, at a given stellar mass, high-redshift galaxies have on average higher SFR and SSFR values than local galaxies. Finally, we explored whether a similar trend could be observed with redshift in the SSFR-(u - B) color diagram, and we hypothesize that a possible (u - B)0 break color may define a characteristic color for the formation of the red sequence.

  18. Measurement and modeling of hydrogen sulfide lagoon emissions from a swine concentrated animal feeding operation.

    PubMed

    Rumsey, Ian C; Aneja, Viney P

    2014-01-01

    Hydrogen sulfide (H2S) emissions were determined from an anaerobic lagoon at a swine concentrated animal feeding operation (CAFO) in North Carolina. Measurements of H2S were made continuously from an anaerobic lagoon using a dynamic flow-through chamber for ∼ 1 week during each of the four seasonal periods from June 2007 through April 2008. H2S lagoon fluxes were highest in the summer with a flux of 3.81 ± 3.24 μg m(-2) min(-1) and lowest in the winter with a flux of 0.08 ± 0.09 μg m(-2) min(-1). An air-manure interface (A-MI) mass transfer model was developed to predict H2S manure emissions. The accuracy of the A-MI mass transfer model in predicting H2S manure emissions was comprehensively evaluated by comparing the model predicted emissions to the continuously measured lagoon emissions using data from all four seasonal periods. In comparison to this measurement data, the A-MI mass transfer model performed well in predicting H2S fluxes with a slope of 1.13 and an r(2) value of 0.60, and a mean bias value of 0.655 μg m(-2) min(-1). The A-MI mass transfer model also performed fairly well in predicting diurnal H2S lagoon flux trends. PMID:24387076

  19. Red Fluorescent Line Emission from Hydrogen Molecules in Diffuse Molecular Clouds

    NASA Technical Reports Server (NTRS)

    Neufeld, David A.; Spaans, Marco

    1996-01-01

    We have modeled the fluorescent pumping of electronic and vibrational emissions of molecular hydrogen (H2) within diffuse molecular clouds that are illuminated by ultraviolet continuum radiation. Fluorescent line intensities are predicted for transitions at ultraviolet, infrared, and red visible wavelengths as functions of the gas density, the visual extinction through the cloud, and the intensity of the incident UV continuum radiation. The observed intensity in each fluorescent transition is roughly proportional to the integrated rate of H2 photodissociation along the line of sight. Although the most luminous fluorescent emissions detectable from ground-based observatories lie at near-infrared wavelengths, we argue that the lower sky brightness at visible wavelengths makes the red fluorescent transitions a particularly sensitive probe. Fabry-Perot spectrographs of the type that have been designed to observe very faint diffuse Ha emissions are soon expected to yield sensitivities that will be adequate to detect H2 vibrational emissions from molecular clouds that are exposed to ultraviolet radiation no stronger than the mean radiation field within the Galaxy. Observations of red H2 fluorescent emission together with cospatial 21 cm H I observations could serve as a valuable probe of the gas density in diffuse molecular clouds.

  20. Revealing the binary origin of Type Ic superluminous supernovae through nebular hydrogen emission

    NASA Astrophysics Data System (ADS)

    Moriya, Takashi J.; Liu, Zheng-Wei; Mackey, Jonathan; Chen, Ting-Wan; Langer, Norbert

    2015-12-01

    We propose that nebular Hα emission, as detected in the Type Ic superluminous supernova iPTF13ehe, stems from matter that is stripped from a companion star when the supernova ejecta collide with it. The temporal evolution, the line broadening, and the overall blueshift of the emission are consistent with this interpretation. We scale the nebular Hα luminosity predicted for Type Ia supernovae in single-degenerate systems to derive the stripped mass required to explain the Hα luminosity of iPTF13ehe. We find a stripped mass of 0.1-0.9 solar masses, assuming that the supernova luminosity is powered by radioactivity or magnetar spin down. Because a central heating source is required to excite the Hα emission, an interaction-powered model is not favored for iPTF13ehe if the Hα emission is from stripped matter. We derive a companion mass of more than 20 solar masses and a binary separation of less than about 20 companion radii based on the stripping efficiency during the collision, indicating that the supernova progenitor and the companion formed a massive close binary system. If Type Ic superluminous supernovae generally occur in massive close binary systems, the early brightening observed previously in several Type Ic superluminous supernovae may also be due to the collision with a close companion. Observations of nebular hydrogen emission in future Type Ic superluminous supernovae will enable us to test this interpretation.

  1. Measurement, analysis, and modeling of hydrogen sulfide emissions from a swine facility in North Carolina

    NASA Astrophysics Data System (ADS)

    Blunden, Jessica

    Annual global source contributions of sulfur compounds to the natural atmospheric environment are estimated to be 142 x 106 tons. Although not quantified, volatilization from animal wastes may be an important source of gaseous reduced sulfur compounds. Hydrogen sulfide (H2S) is a colorless gas emitted during decomposition of hog manure that produces an offensive "rotten egg" odor. Once released into the atmosphere, H 2S is oxidized and the eventual byproduct, sulfuric acid, may combine with other atmospheric constituents to form aerosol products such as ammonium bisulfate and ammonium sulfate. In recent years, confined animal feeding operations (CAFOs) have increased in size, resulting in more geographically concentrated areas of animals and, subsequently, animal waste. In North Carolina and across the southeastern United States anaerobic waste treatment lagoons are traditionally used to store and treat hog excreta at commercial hog farms. Currently, no state regulations exist for H2S gaseous emissions from animal production facilities in North Carolina and the amount of H2S being emitted into the atmosphere from these potential sources is widely unknown. In response to the need for data, this research initiative has been undertaken in an effort to quantify emissions of H2S from swine CAFOs. An experimental study was conducted at a commercial swine farm in eastern North Carolina to measure hydrogen sulfide emissions from a hog housing unit utilizing a mechanical fan ventilation system and from an on-site waste storage treatment lagoon. A dynamic flow-through chamber system was employed to make lagoon flux measurements. Semi-continuous measurements were made over a one-year period (2004-2005) for a few days during each of the four predominant seasons in order to assess diurnal and temporal variability in emissions. Fan rpm from the barn was continuously measured and flow rates were calculated in order to accurately assess gaseous emissions from the system

  2. On the hydrogen emission from the type Ia supernova 2002ic

    SciTech Connect

    Wang, Lifan; Baade, Dietrich; Hoflich, Peter; Wheeler, J. Craig; Kawabata, Koji; Nomoto, Ken'ichi

    2003-12-10

    The discovery of SN 2002ic by the Supernova Factory and the subsequent spectroscopic studies have led to the surprising finding that SN 2002ic is a type Ia supernova with strong ejecta-circumstellar interaction. Here we show that nearly 1 year after the explosion the supernova has become fainter overall, but the H-alpha emission has brightened and broadened dramatically compared to earlier observations. We have obtained spectropolarimetry data which show that the hydrogen-rich matter is highly aspherically distributed. These observations suggest that the supernova exploded inside a dense, clumpy, disk-like circumstellar environment.

  3. Factors Affecting VUV Emission Spectrum near Lyman-{alpha} from a Hydrogen Plasma Source

    SciTech Connect

    Ogino, K.; Kasuya, T.; Shimamoto, S.; Wada, M.; Kimura, Y.; Nishiura, M.

    2011-09-26

    Vacuum ultra violet (VUV) emission spectra from plasmas near walls of different metallic materials were measured to estimate the effect upon the local production rate of vibrational excited hydrogen molecules due to plasma wall interaction. Among Cu, Mo, Ni, Ta and Ti, the intensity of band spectrum around Lyman-{alpha} had become the largest when Cu wall was used while it was the smallest for Ti. The role of particle reflection from the plasma electrode surface upon the H{sup -} production by a pure electron volume process is discussed.

  4. Investigation of SRS conversion of XeCl laser emission in lead vapor, methane, and hydrogen

    SciTech Connect

    Mel'chenko, S.V.; Panchenko, A.N.; Tarasenko, V.F.; Evtushenko, G.S. )

    1994-01-01

    The rapid advances in the development of electric-discharge exciplex lasers and powerful effective sources of UV coherent radiation have uncovered far-reaching prospects for their practical use in various fields of sciences and engineering, such as microelectronics, medicine, ecology (remote detection of contamination in the atmosphere), photochemistry, plasma diagnostics, and others. The wavelength range in which high-power coherent radiation is possible can be greatly expanded by using stimulated Raman scattering (SRS) in metal vapor and compressed gases. This paper is devoted to an investigation of the optimal conditions of SRS-conversion of XeCl-laser emission in lead vapor, methane, and hydrogen.

  5. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On view in front of the Headquarters Building, the Zero Emissions (ZE) transit bus attracts an interested group of employees, including Center Director Roy Bridges (second from left in foreground). Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  6. Hydrogen-oxygen driven Zero Emissions bus drives around KSC Visitor Complex

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Zero Emissions (ZE) transit bus passes a mock-up orbiter named Explorer on a trek through the KSC Visitor Complex. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept.

  7. Hydrogen-oxygen driven Zero Emissions bus drives around KSC Visitor Complex

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Zero Emissions (ZE) transit bus tours the KSC Visitor Complex for a test ride. In the background are a mock-up orbiter named Explorer (left) and a stack of solid rocket boosters and external tank (right), typically used on Shuttle launches. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept.

  8. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    KSC workers, with Center Director Roy Bridges (at right next to bus), head for the open door of the Zero Emissions (ZE) transit bus and a ride around the center. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available to employees for viewing and a ride, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  9. HLINOP: Hydrogen LINe OPacity in stellar atmospheres

    NASA Astrophysics Data System (ADS)

    Barklem, P. S.; Piskunov, N.

    2015-07-01

    HLINOP is a collection of codes for computing hydrogen line profiles and opacities in the conditions typical of stellar atmospheres. It includes HLINOP for approximate quick calculation of any line of neutral hydrogen (suitable for model atmosphere calculations), based on the Fortran code of Kurucz and Peterson found in ATLAS9. It also includes HLINPROF, for detailed, accurate calculation of lower Balmer line profiles (suitable for detailed analysis of Balmer lines) and HBOP, to implement the occupation probability formalism of Daeppen, Anderson and Milhalas (1987) and thus account for the merging of bound-bound and bound-free opacity (used often as a wrapper to HLINOP for model atmosphere calculations).

  10. Reduction of combustion emissions using hydrogen peroxide in a pilot scale combustion chamber

    SciTech Connect

    Martinez, A.I.; Corredor, L.F.; Tamara, W.

    1997-12-31

    A hydrogen peroxide injection system was designed and installed in the stack of a 5,274 million J/hr industrial pilot plant scale combustion chamber using natural gas as fuel. The concentration of peroxide in the gas stream was precisely controlled by continuous injection using an electromagnetic dosage pump, the liquid 50% peroxide solution was finely dispersed into the gases by a water cooled custom designed delivery system with a spray nozzle at the tip. Residence times between 0.1 and 1.8 seconds and concentrations of H{sub 2}O{sub 2} between 280 ppm and 4,000 ppm were used during the test runs. CEMS for total hydrocarbons, carbon monoxide, nitrogen oxides, as well as an ultrasonic gas flow monitor were used to measure the effect of hydrogen peroxide in reducing the emissions of these pollutants. Destruction removal efficiencies between 25% and 100% were observed for hydrocarbons, and concentrations of CO, as well as NO{sub x}. were reduced about 50%. The results indicate that this labscale proved technology yields similar results in reducing combustion emissions in pilot applications, and also a reliable injection system has been developed and tested successfully.

  11. Potential energy and greenhouse gas emission effects of hydrogen production from coke oven gas in U.S. Steel Mills.

    SciTech Connect

    Joseck, F.; Wang, M.; Wu, Y.; Energy Systems; DOE

    2008-02-01

    For this study, we examined the energy and emission effects of hydrogen production from coke oven gas (COG) on a well-to-wheels basis and compared these effects with those of other hydrogen production options, as well as with those of conventional gasoline and diesel options. We then estimated the magnitude of hydrogen production from COG in the United States and the number of hydrogen fuel cell vehicles (FCVs) that could potentially be fueled with the hydrogen produced from COG. Our analysis shows that this production pathway can achieve energy and greenhouse gas emission reduction benefits. This pathway is especially worth considering because first, the sources of COG are concentrated in the upper Midwest and in the Northeast United States, which would facilitate relatively cost-effective collection, transportation, and distribution of the produced hydrogen to refueling stations in these regions. Second, the amount of hydrogen that could be produced may fuel about 1.7 million cars, thus providing a vital near-term hydrogen production option for FCV applications.

  12. 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.

  13. New Observations of Balmer Continuum Flux in Solar Flares. Instrument Description and First Results

    NASA Astrophysics Data System (ADS)

    Kotrč, P.; Procházka, O.; Heinzel, P.

    2016-03-01

    Increase in the Balmer continuum radiation during solar flares was predicted by various authors, but has never been firmly confirmed observationally using ground-based slit spectrographs. Here we describe a new post-focal instrument, the image selector, with which the Balmer continuum flux can be measured from the whole flare area, in analogy to successful detections of flaring dMe stars. The system was developed and put into operation at the horizontal solar telescope HSFA2 of the Ondřejov Observatory. We measure the total flux by a fast spectrometer from a limited but well-defined region on the solar disk. Using a system of diaphragms, the disturbing contribution of a bright solar disk can be eliminated as much as possible. Light curves of the measured flux in the spectral range 350 - 440 nm are processed, together with the Hα images of the flaring area delimited by the appropriate diaphragm. The spectral flux data are flat-fielded, calibrated, and processed to be compared with model predictions. Our analysis of the data proves that the described device is sufficiently sensitive to detect variations in the Balmer continuum during solar flares. Assuming that the Balmer-continuum kernels have at least a similar size as those visible in Hα, we find the flux increase in the Balmer continuum to reach 230 - 550 % of the quiet continuum during the observed X-class flare. We also found temporal changes in the Balmer continuum flux starting well before the onset of the flare in Hα.

  14. Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers

    NASA Astrophysics Data System (ADS)

    Deane, R. P.; Obreschkow, D.; Heywood, I.

    2015-09-01

    Strong gravitational lensing provides some of the deepest views of the Universe, enabling studies of high-redshift galaxies only possible with next-generation facilities without the lensing phenomenon. To date, 21-cm radio emission from neutral hydrogen has only been detected directly out to z ˜ 0.2, limited by the sensitivity and instantaneous bandwidth of current radio telescopes. We discuss how current and future radio interferometers such as the Square Kilometre Array (SKA) will detect lensed H I emission in individual galaxies at high redshift. Our calculations rely on a semi-analytic galaxy simulation with realistic H I discs (by size, density profile and rotation), in a cosmological context, combined with general relativistic ray tracing. Wide-field, blind H I surveys with the SKA are predicted to be efficient at discovering lensed H I systems, increasingly so at z ≳ 2. This will be enabled by the combination of the magnification boosts, the steepness of the H I luminosity function at the high-mass end, and the fact that the H I spectral line is relatively isolated in frequency. These surveys will simultaneously provide a new technique for foreground lens selection and yield the highest redshift H I emission detections. More near term (and existing) cm-wave facilities will push the high-redshift H I envelope through targeted surveys of known lenses.

  15. Role of lubrication oil in particulate emissions from a hydrogen-powered internal combustion engine.

    PubMed

    Miller, Arthur L; Stipe, Christopher B; Habjan, Matthew C; Ahlstrand, Gilbert G

    2007-10-01

    Recent studies suggest that trace metals emitted by internal combustion engines are derived mainly from combustion of lubrication oil. This hypothesis was examined by investigation of the formation of particulate matter emitted from an internal combustion engine in the absence of fuel-derived soot. Emissions from a modified CAT 3304 diesel engine fueled with hydrogen gas were characterized. The role of organic carbon and metals from lubrication oil on particle formation was investigated under selected engine conditions. The engine produced exhaust aerosol with log normal-size distributions and particle concentrations between 10(5) and 10(7) cm(-3) with geometric mean diameters from 18 to 31 nm. The particles contained organic carbon, little or no elemental carbon, and a much larger percentage of metals than particles from diesel engines. The maximum total carbon emission rate was estimated at 1.08 g h(-1), which is much lower than the emission rate of the original diesel engine. There was also evidence that less volatile elements, such as iron, self-nucleated to form nanoparticles, some of which survive the coagulation process. PMID:17969702

  16. Experimental investigation of solid hydrogen pellet ablation in high-temperature plasmas using holographic interferometry and other diagnostics

    SciTech Connect

    Thomas, Jr., C. E.

    1981-03-01

    The technology currently most favored for the refueling of fusion reactors is the high-velocity injection of solid hydrogen pellets. Design details are presented for a holographic interferometer/shadowgraph used to study the microscopic characteristics of a solid hydrogen pellet ablating in an approx. 1-keV plasma. Experimental data are presented for two sets of experiments in which the interferometer/shadowgraph was used to study approx. 1-mm-diam solid hydrogen pellets injected into the Impurity Study Experiment (ISX-B) tokamak at Oak Ridge National Laboratory (ORNL) at velocities of 1000 m/s. In addition to the use of the holographic interferometer, the pellet ablation process is diagnosed by studying the emission of Balmer-alpha photons and by using the available tokamak diagnostics (Thomson scattering, microwave/far-infrared interferometer, pyroelectric radiometer, hard x-ray detector).

  17. BLACK HOLE MASS ESTIMATES BASED ON C IV ARE CONSISTENT WITH THOSE BASED ON THE BALMER LINES

    SciTech Connect

    Assef, R. J.; Denney, K. D.; Kochanek, C. S.; Peterson, B. M.; Kozlowski, S.; Dietrich, M.; Grier, C. J.; Khan, R.; Ageorges, N.; Buschkamp, P.; Gemperlein, H.; Hofmann, R.; Barrows, R. S.; Falco, E.; Kilic, M.; Feiz, C.; Germeroth, A.; Juette, M.; Knierim, V.; Laun, W.; and others

    2011-12-01

    Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on the C IV, H{alpha}, and H{beta} broad emission lines. Our sample is based upon that of Greene, Peng, and Ludwig, expanded with new near-IR spectroscopic observations, consistently analyzed high signal-to-noise ratio (S/N) optical spectra, and consistent continuum luminosity estimates at 5100 A. We find that BH mass estimates based on the full width at half-maximum (FWHM) of C IV show a systematic offset with respect to those obtained from the line dispersion, {sigma}{sub l}, of the same emission line, but not with those obtained from the FWHM of H{alpha} and H{beta}. The magnitude of the offset depends on the treatment of the He II and Fe II emission blended with C IV, but there is little scatter for any fixed measurement prescription. While we otherwise find no systematic offsets between C IV and Balmer line mass estimates, we do find that the residuals between them are strongly correlated with the ratio of the UV and optical continuum luminosities. This means that much of the dispersion in previous comparisons of C IV and H{beta} BH mass estimates are due to the continuum luminosities rather than to any properties of the lines. Removing this dependency reduces the scatter between the UV- and optical-based BH mass estimates by a factor of approximately two, from roughly 0.35 to 0.18 dex. The dispersion is smallest when comparing the C IV {sigma}{sub l} mass estimate, after removing the offset from the FWHM estimates, and either Balmer line mass estimate. The correlation with the continuum slope is likely due to a combination of reddening, host contamination, and object-dependent SED shapes. When we add additional heterogeneous measurements from the literature, the results are unchanged. Moreover, in a trial observation of a

  18. Hydrogen line ratios in Seyfert galaxies and low redshift quasars

    NASA Technical Reports Server (NTRS)

    Kriss, G. R.

    1984-01-01

    New observations of the Lymal alpha radiation/hydrogen alpha radiation ratio in a set of X-ray selected active galactic nuclei and an archival study of International Ultraviolet Explorer (IUE) observations of Lymal alpha low redshift quasars and Seyfert galaxies have been used to form a large sample for studying the influence of soft X-rays on the enhancement of Balmer emission in the broad line region. In common models of broad line clouds, the Balmer lines are formed deep in the interior, largely by collisional excitation. Heating within the clouds is provided by soft X-ray radiation, while Lymal alpha is formed mainly by recombination after photoionization. The ratio Lymal alpha/Halpha is expected to depend weakly on the ratio of ionizing ultraviolet luminosity to X-ray luminosity (L sub UV/l sub x). If the Lymal alpha luminosity is used as a measure of L sub UV' a weak dependence of Lymal/H alpha on the X-ray luminosity is found similar to previous results.

  19. Numerical and experimental study of atomic transport and Balmer line intensity in Linac4 negative ion source

    SciTech Connect

    Shibata, T. Nishida, K.; Hatayama, A.; Mattei, S.; Lettry, J.

    2015-04-08

    Time structure of Balmer H{sub α} line intensity in Linac4 RF plasma has been analyzed by the combined simulation model of atomic transport and Collisional-Radiative models. As a preliminary result, time variation of the line intensity in the ignition phase of RF plasma is calculated and compared with the experimental results by photometry. For the comparison, spatial distribution of the local H{sub α} photon emission rate at each time is calculated from the numerical model. The contribution of the local photon emission rates to the observed line intensity via optical viewing port is also investigated by application of the mock-up of the optical viewing port and the known light source. It has been clarified from the analyses that the higher and the lower peaks of the H{sub α} line intensity observed during 1 RF cycle is mainly due to the different spatial distributions in the electron energy distribution function and the resultant local photon emission rate. These results support previous suggestion that the existence of the capacitive electric field in axial direction leads to the higher/lower peaks of the line intensity.

  20. Feasibility of hydrogen density estimation from tomographic sensing of Lyman alpha emission

    NASA Astrophysics Data System (ADS)

    Waldrop, L.; Kamalabadi, F.; Ren, D.

    2015-12-01

    In this work, we describe the scientific motivation, basic principles, and feasibility of a new approach to the estimation of neutral hydrogen (H) density in the terrestrial exosphere based on the 3-D tomographic sensing of optically thin H emission at 121.6 nm (Lyman alpha). In contrast to existing techniques, Lyman alpha tomography allows for model-independent reconstruction of the underlying H distribution in support of investigations regarding the origin and time-dependent evolution of exospheric structure. We quantitatively describe the trade-off space between the measurement sampling rate, viewing geometry, and the spatial and temporal resolution of the reconstruction that is supported by the data. We demonstrate that this approach is feasible from either earth-orbiting satellites such as the stereoscopic NASA TWINS mission or from a CubeSat platform along a trans-exosphere trajectory such as that enabled by the upcoming Exploration Mission 1 launch.

  1. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  2. Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C.; Edmonds, Ryan G.; Williams, Joseph T.; Baldwin, Stephen P.

    2009-10-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  3. Hydrogen isotopes preclude marine hydrate CH4 emissions at the onset of Dansgaard-Oeschger events.

    PubMed

    Bock, Michael; Schmitt, Jochen; Möller, Lars; Spahni, Renato; Blunier, Thomas; Fischer, Hubertus

    2010-06-25

    The causes of past changes in the global methane cycle and especially the role of marine methane hydrate (clathrate) destabilization events are a matter of debate. Here we present evidence from the North Greenland Ice Core Project ice core based on the hydrogen isotopic composition of methane [deltaD(CH4)] that clathrates did not cause atmospheric methane concentration to rise at the onset of Dansgaard-Oeschger (DO) events 7 and 8. Box modeling supports boreal wetland emissions as the most likely explanation for the interstadial increase. Moreover, our data show that deltaD(CH4) dropped 500 years before the onset of DO 8, with CH4 concentration rising only slightly. This can be explained by an early climate response of boreal wetlands, which carry the strongly depleted isotopic signature of high-latitude precipitation at that time. PMID:20576890

  4. The hydrogen sulfide emissions abatement program at the Geysers Geothermal Power Plant

    NASA Technical Reports Server (NTRS)

    Allen, G. W.; Mccluer, H. K.

    1974-01-01

    The scope of the hydrogen sulfide (H2S) abatement program at The Geysers Geothermal Power Plant and the measures currently under way to reduce these emissions are discussed. The Geysers steam averages 223 ppm H2S by weight and after passing through the turbines leaves the plant both through the gas ejector system and by air-stripping in the cooling towers. The sulfide dissolved in the cooling water is controlled by the use of an oxidation catalyst such as an iron salt. The H2S in the low Btu ejector off gases may be burned to sulfur dioxide and scrubbed directly into the circulating water and reinjected into the steam field with the excess condensate. Details are included concerning the disposal of the impure sulfur, design requirements for retrofitting existing plants and modified plant operating procedures. Discussion of future research aimed at improving the H2S abatement system is also included.

  5. Measurement of the stratospheric hydrogen peroxide concentration profile using far infrared thermal emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Johnson, D. G.; Traub, W. A.; Jucks, K. W.

    1991-01-01

    The first unequivocal measurement of hydrogen peroxide in the stratosphere have been made, a concentration profile obtained from a balloon platform using Fourier transform thermal emission spectroscopy in the far infrared. Measurements were made using the 112/cm R-Q5 branch of the rotational-torsional spectrum, with some confirmation from the 94/cm R-Q4 branch. The volume mixing ratio of H2O2 is 1.6 x 10 to the -10th at 38.4 km, decreasing to 0.6 x 10 to the -10th at 23.8 km, with uncertainties of about 16 percent. These measurements are compared to a recent stratospheric model calculation.

  6. Mitigation of Hydrogen Sulfide Emissions in the Geysers KGRA (Staff Draft)

    SciTech Connect

    Buell, Richard

    1981-07-01

    Violations of the ambient air quality standard (AAQS) for hydrogen sulfide (H2S) are currently being experienced in The Geysers KGRA and could significantly increase in the future. Attainment and maintenance of the H2S AAQS is a potential constraint to optimum development of this resource. The availability of reliable H2S controls and the development of a validated air dispersion model are critical to alleviating this constraint. The purpose of this report is to assess the performance capabilities for state-of-the-art controls, to identify potential cost-effective alternative controls, and to identify the California Energy Commission (CEC) staffs efforts to develop a validated air dispersion model. Currently available controls (Stretford, Hydrogen Peroxide, and EIC) are capable of abating H2S emissions from a proposed facility to five lbs/hr. Alternative controls, such as condensate stripping and condensate pH control, appear to promising, cost-effective control option. The CEC staff is currently developing a validated air dispersion model for The Geysers KGRA. The CEC staff recommends investigation of retrofit control options for existing units, investigation of alternative control technologies, and dispersion analysis for optimum plant location in order to maximize the development potential of The Geysers KGRA. Energy cost studies suggest that the EIC process would be the most cost-effective for retrofits at The Geysers. (DJE-2005)

  7. Hydrogen-bond promoted nucleophilic fluorination: concept, mechanism and applications in positron emission tomography.

    PubMed

    Lee, Ji-Woong; Oliveira, Maria Teresa; Jang, Hyeong Bin; Lee, Sungyul; Chi, Dae Yoon; Kim, Dong Wook; Song, Choong Eui

    2016-08-22

    Due to the tremendous interest in carbon-fluorine bond-forming reactions, research efforts in this area have been dedicated to the development of facile processes to synthesize small fluorine-containing organic molecules. Among others, PET (Positron Emission Tomography) is one of the most important applications of fluorine chemistry. Recognizing the specific requirements of PET processes, some groups have focused on fluorination reactions using alkali metal fluorides, particularly through SN2-type reactions. However, a common "misconception" about the role of protic solvents and hydrogen bonding interactions in this class of reactions has hampered the employment of these excellent promoters. Herein, we would like to review recent discoveries in this context, showing straightforward nucleophilic fluorination reactions using alkali metal fluorides promoted by protic solvents. Simultaneous dual activation of reacting partners by intermolecular hydrogen bonding and the enhancement of the "effective fluoride nucleophilicity", which is Nature's biocatalytic approach with the fluorinase enzyme, are the key to this unprecedentedly successful nucleophilic fluorination. PMID:27264160

  8. Molecular hydrogen emission in L1448 associated with a highly collimated molecular outflow

    NASA Technical Reports Server (NTRS)

    Terebey, Susan

    1991-01-01

    A near-infrared camera was used to search for jets around low-luminosity embedded infrared sources in nearby molecular clouds. The near-infrared offers the advantage that the extinction is very low compared with the optical. A jet is detected in molecular hydrogen at 2.12 microns toward a source in L1448. Given the sample size this indicates a detection rate of no more than a couple percent. The average visual extinction in L1448 is roughly 5 mag. The properties of the molecular hydrogen emission are similar to those measured for known Herbig-Haro objects, suggesting the jet is a buried Herbig-Haro object/jet that would be visible in the optical if the extinction were lower. The L1448 jet coincides with the unusual CO outflow that is highly collimated and contains high-velocity CO 'bullets'. The properties of the L1448 source suggest it defines a transition case between molecular outflows and Herbig-Haro jets, combining the characteristics of both.

  9. Effect of annealing in hydrogen atmosphere on ZnO films for field emission display

    NASA Astrophysics Data System (ADS)

    Zulkifli, Zurita; Sharma, Subash; Shinde, Sachin; Kalita, Golap; Tanemura, M.

    2015-11-01

    Surface morphology, crystallinity, conductivity and optical transmittance of ZnO films can be modified by annealing process. Hydrogen is one of the popular annealing gases as well as nitrogen, argon, oxygen and air which are commonly used for thin film cleaning or the removal of native oxide. In general, annealing is done at high temperatures (> 600degC) to improve the film properties. From a view point of environment, however, lower annealing temperature is preferable. In this work, low annealing process was challenged to understand the effect of annealing temperature on properties of ZnO thin films and nanostructured film grown on glass substrates for transparent field emission device applications. The annealing temperature employed was 100, 200 and 450°C at 100 sccm hydrogen flow rate. ZnO thin films were deposited by RF magnetron sputtering. The ZnO thin films were characterized by X-ray diffraction analysis (XRD), Atomic Force Microscopy (AFM), UV-VIS and Raman spectroscopy. The sheet resistances reduced about 15 kohm/sq at low annealing temperature. By contrast, the optical transmittance did not show any significant changes after annealing. The FE current density increased after the ZnO nanostructures film was annealed in 100°C. The results obtained could motivate a surface treatment for flexible ZnO thin film since the substrate is always suffered by heat.

  10. The formation of emission lines in quasars and Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Kwan, J.; Krolik, J. H.

    1981-01-01

    The photoionization and heating throughout a quasar emission-line cloud optically thick at the Lyman edge are calculated. Photoionization and collisional ionization from excited states of hydrogen are included, which maintain a substantial electron fraction after the exhaustion of Lyman continuum photons halts ground-state photoionization. Observed values are explained for Ly-alpha/H-beta, H-alpha/H-beta, P-alpha/H-alpha, He I 5876/H-beta, O I 8446/H-alpha, and Mg II 2798/H-beta. The dependence of line strengths on physical conditions is discussed, and plotting Fe II/4570/H-beta versus Balmer continuum/H-beta is suggested. Other observations are also suggested, and the degree of asymmetry is given between the forward and backward emission of lines from a finite slab to make possible the use of comparative line profile studies to elucidate cloud kinematics.

  11. Borax and Octabor Treatment of Stored Swine Manure: Reduction in Hydrogen Sulfide Emissions and Phytotoxicity to Agronomic Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gaseous emissions from stored manure have become environmental and health issues for humans and animals as the livestock industry becomes specialized and concentrated. Of particular concern is hydrogen sulfide, which is being targeted for regulatory control in concentrated animal farm operations. ...

  12. Exhaust Emissions and Fuel Properties of Partially Hydrogenated Soybean Oil Methyl Esters Blended with Ultra Low Sulfur Diesel Fuel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Important fuel properties and emissions characteristics of blends (20 vol%) of soybean oil methyl esters (SME) and partially hydrogenated SME (PHSME) in ultra low sulfur diesel fuel (ULSD) were determined and compared with neat ULSD. The following changes in physical properties were noticed for B20...

  13. Flame Emission Spectrometry in General Chemistry Labs: Solubility Product (K[subscript sp]) of Potassium Hydrogen Phthalate

    ERIC Educational Resources Information Center

    Nyasulu, Frazier W.; Cusworth, William, III; Lindquist, David; Mackin, John

    2007-01-01

    In this general chemistry laboratory, flame emission spectrometry is used to determine the potassium ion concentration in saturated solutions of potassium hydrogen phthalate (KHP) in the 0-65 [degree]C temperature range. From these data the solubility products (K[subscript sp]), the Gibbs free energies of solution ([Delta][subscript…

  14. Borax and octabor treatment of stored swine manure to reduce sulfate reducing bacteria and hydrogen sulfide emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odorous gas emissions from stored swine manure are becoming serious environmental and health issues as the livestock industry becomes more specialized, concentrated, and industrialized. These nuisance gasses include hydrogen sulfide (H2S), ammonia, and methane, which are produced as a result of ana...

  15. Neutron emission from JET DT plasmas with RF heating on minority hydrogen

    NASA Astrophysics Data System (ADS)

    Henriksson, H.; Conroy, S.; Ericsson, G.; Gorini, G.; Hjalmarsson, A.; Källne, J.; Tardocchi, M.; EFDA-JET Workprogramme, contributors to the

    2002-07-01

    The neutron emission spectrum from d+t→α+n reactions has been measured as a means to study the plasma response to radio frequency (RF) power coupled to hydrogen and deuteron minority components (through fundamental and second harmonic, respectively) in a tritium discharge at JET. The spectrum was measured with the magnetic proton recoil spectrometer and was analysed in terms of two spectral components due to thermal (TH) and high-energy (HE) deuterons interacting with the bulk ion population of thermal tritons. The results were used to derive information on the deuteron population in terms of temperatures (TTH and THE) as well as corresponding particle and kinetic energy densities of the plasma; the bulk ion temperature (Ti = TTH) was determined both before (with Ohmic heating only) and during the RF pulse. Similar information on protons was derived from other measurements in order to estimate the different RF effects on protons and deuterons. This paper illustrates qualitatively the type of empirical ion kinetic information that can be obtained from neutron emission spectroscopy; the data serves as a basis for comparison with results of predictive and interpretative models on RF effects in plasmas.

  16. The origin of molecular hydrogen emission in cooling-flow filaments

    NASA Astrophysics Data System (ADS)

    Ferland, G. J.; Fabian, A. C.; Hatch, N. A.; Johnstone, R. M.; Porter, R. L.; van Hoof, P. A. M.; Williams, R. J. R.

    2008-05-01

    The optical filaments found in many cooling flows in galaxy clusters consist of low-density (~103cm-3) cool (~103 K) gas surrounded by significant amounts of cosmic-ray and magnetic field energy. Their spectra show anomalously strong low-ionization and molecular emission lines when compared with Galactic molecular clouds exposed to ionizing radiation such as the Orion complex. Previous studies have shown that the spectra cannot be produced by O-star photoionization. Here, we calculate the physical conditions in dusty gas that is well shielded from external sources of ionizing photons and is energized either by cosmic rays or dissipative magnetohydrodynamics waves. Strong molecular hydrogen lines, with relative intensities similar to those observed, are produced. Selection effects introduced by the microphysics produce a correlation between the H2 line upper level energy and the population temperature. These selection effects allow a purely collisional gas to produce H2 emission that masquerades as starlight-pumped H2 but with intensities that are far stronger. This physics may find application to any environment where a broad range of gas densities or heating rates occur. Contains material ©British Crown copyright 2008/MoD. E-mail: gary@pa.uky.edu

  17. Quantifying Molecular Hydrogen Emissions and an Industrial Leakage Rate for the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Irish, M. C.; Schroeder, J.; Beyersdorf, A. J.; Blake, D. R.

    2015-12-01

    The poorly understood atmospheric budget and distribution of molecular hydrogen (H2) have invited further research since the discovery that emissions from a hydrogen-based economy could have negative impacts on the global climate system and stratospheric ozone. The burgeoning fuel cell electric vehicle industry in the South Coast Air Basin of California (SoCAB) presents an opportunity to observe and constrain urban anthropogenic H2 emissions. This work presents the first H2 emissions estimate for the SoCAB and calculates an upper limit for the current rate of leakage from production and distribution infrastructure within the region. A top-down method utilized whole air samples collected during the Student Airborne Research Program (SARP) onboard the NASA DC-8 research aircraft from 23-25 June 2015 to estimate H2 emissions from combustion and non-combustion sources. H2:carbon monoxide (CO) and H2:carbon dioxide ratios from airborne observations were compared with experimentally established ratios from pure combustion source ratios and scaled with the well-constrained CO emissions inventory to yield H2 emissions of 24.9 ± 3.6 Gg a-1 (1σ) from combustion engines and 8.2 ± 4.7 Gg a-1 from non-combustion sources. Total daily production of H2 in the SoCAB was compared with the top-down results to estimate an upper limit leakage rate (5%) where all emissions not accounted for by incomplete combustion in engines were assumed to be emitted from H2 infrastructure. For bottom-up validation, the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory dispersion model was run iteratively with all known stationary sources in attempt to constrain emissions. While this investigation determined that H2 emissions from non-combustion sources in the SoCAB are likely significant, more in-depth analysis is required to better predict the atmospheric implications of a hydrogen economy.

  18. The Balmer-dominated northeast limb of the Cygnus loop supernova remnant

    NASA Technical Reports Server (NTRS)

    Hester, J. Jeff; Raymond, John C.; Blair, William P.

    1994-01-01

    We present a comprehensive investigation of the Balmar-dominated northeast limb of the Cygnus Loop supernova remnant. Data presented include H alpha (O III), and X-ray images, UV and visible spectrophotometry, and high-resolution spectroscophy. The two relatively bright Balmer-dominated filaments visible on the POSS prints are seen to be part of a very smooth and regular complex of filaments. These filaments mark the current location of the blast wave and are seen to bound the sharply limb-brightened X-ray emission, including the previously reported X-ray, 'halo.' The (O III)/h beta ratio throughout the region is approximately 0.1, except for regions in which the shock is undergoing a transition from nonradiative to incomplete radiative to incomplete radiative conditions. At these locations (O III) emission from the cooling region is quite strong, while collisionally excited Balmer-line emission can be weak because of photoionization of the preshock medium by UV from the nascent cooling region. As a result (O III)/H beta is greater than 100 in some locations. The nonradiative/radiative transition is best studied along the length of the northwestern of the two brightest filaments, where the shock velocity and swept-up column go from approximately 180 km/s and 10(exp 17)/sq cm at one end to approximately 140 km/s and 8 x 10(exp 17)/cm at the other. There are also a number of locations of such incomplete radiative emission where the shock has recently encountered denser regions with characteristic sizes of approximately 10(exp 18) cm. There is a considerable amount of evidence that the shock has decelerated from approximately 400 km/s to less than 200 km/s in the last 1000 yr. We interpret this as the result of the blast wave hitting the wall of a cavity which surround the supernova precursor and succeed in matching a wide range of data with a reflected shock model in which the density ofthe cavity wall is approximately 1.2/cu cm and the density in the interior of the

  19. ON THE APPARENT ASSOCIATIONS BETWEEN INTERSTELLAR NEUTRAL HYDROGEN STRUCTURE AND (WMAP) HIGH-FREQUENCY CONTINUUM EMISSION

    SciTech Connect

    Verschuur, Gerrit L.

    2010-03-10

    Galactic neutral hydrogen (H I) within a few hundred parsecs of the Sun contains structure with an angular distribution that is similar to small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP). A total of 108 associated pairs of associated H I and WMAP features have now been cataloged using H I data mapped in 2 km s{sup -1} intervals and these pairs show a typical offset of 0.{sup 0}8. A large-scale statistical test for a direct association is carried out that casts little additional light on whether the these small offsets are merely coincidental or carry information. To pursue the issue further, the nature of several of the features within the foreground H I most closely associated with WMAP structure is examined in detail and it is shown that the cross-correlation coefficient for well-matched pairs of structures is of order unity. It is shown that free-free emission from electrons in unresolved density enhancements in interstellar space could theoretically produce high-frequency radio continuum radiation at the levels observed by WMAP and that such emission will appear nearly flat across the WMAP frequency range. Evidence for such structure in the interstellar medium already exists in the literature. Until higher angular resolution observations of the high-frequency continuum emission structure as well as the apparently associated H I structure become available, it may be difficult to rule out the possibility that some if not all the small-scale structure usually attributed to the cosmic microwave background may have a galactic origin.

  20. SPITZER INFRARED SPECTROGRAPH DETECTION OF MOLECULAR HYDROGEN ROTATIONAL EMISSION TOWARDS TRANSLUCENT CLOUDS

    SciTech Connect

    Ingalls, James G.; Bania, T. M.; Boulanger, F.; Draine, B. T.; Falgarone, E.; Hily-Blant, P. E-mail: bania@bu.edu E-mail: draine@astro.princeton.edu E-mail: pierre.hilyblant@obs.ujf-grenoble.fr

    2011-12-20

    Using the Infrared Spectrograph on board the Spitzer Space Telescope, we have detected emission in the S(0), S(1), and S(2) pure-rotational (v = 0-0) transitions of molecular hydrogen (H{sub 2}) toward six positions in two translucent high Galactic latitude clouds, DCld 300.2-16.9 and LDN 1780. The detection of these lines raises important questions regarding the physical conditions inside low-extinction clouds that are far from ultraviolet radiation sources. The ratio between the S(2) flux and the flux from polycyclic aromatic hydrocarbons (PAHs) at 7.9 {mu}m averages 0.007 for these six positions. This is a factor of about four higher than the same ratio measured toward the central regions of non-active Galaxies in the Spitzer Infrared Nearby Galaxies Survey. Thus, the environment of these translucent clouds is more efficient at producing rotationally excited H{sub 2} per PAH-exciting photon than the disks of entire galaxies. Excitation analysis finds that the S(1) and S(2) emitting regions are warm (T {approx}> 300 K), but comprise no more than 2% of the gas mass. We find that UV photons cannot be the sole source of excitation in these regions and suggest mechanical heating via shocks or turbulent dissipation as the dominant cause of the emission. The clouds are located on the outskirts of the Scorpius-Centaurus OB association and may be dissipating recent bursts of mechanical energy input from supernova explosions. We suggest that pockets of warm gas in diffuse or translucent clouds, integrated over the disks of galaxies, may represent a major source of all non-active galaxy H{sub 2} emission.

  1. On the Apparent Associations Between Interstellar Neutral Hydrogen Structure and (WMAP) High-frequency Continuum Emission

    NASA Astrophysics Data System (ADS)

    Verschuur, Gerrit L.

    2010-03-01

    Galactic neutral hydrogen (H I) within a few hundred parsecs of the Sun contains structure with an angular distribution that is similar to small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP). A total of 108 associated pairs of associated H I and WMAP features have now been cataloged using H I data mapped in 2 km s-1 intervals and these pairs show a typical offset of 0fdg8. A large-scale statistical test for a direct association is carried out that casts little additional light on whether the these small offsets are merely coincidental or carry information. To pursue the issue further, the nature of several of the features within the foreground H I most closely associated with WMAP structure is examined in detail and it is shown that the cross-correlation coefficient for well-matched pairs of structures is of order unity. It is shown that free-free emission from electrons in unresolved density enhancements in interstellar space could theoretically produce high-frequency radio continuum radiation at the levels observed by WMAP and that such emission will appear nearly flat across the WMAP frequency range. Evidence for such structure in the interstellar medium already exists in the literature. Until higher angular resolution observations of the high-frequency continuum emission structure as well as the apparently associated H I structure become available, it may be difficult to rule out the possibility that some if not all the small-scale structure usually attributed to the cosmic microwave background may have a galactic origin.

  2. Activation of extended red emission photoluminescence in carbon solids by exposure to atomic hydrogen and UV radiation

    NASA Technical Reports Server (NTRS)

    Furton, Douglas G.; Witt, Adolf N.

    1993-01-01

    We report on new laboratory results which relate directly to the observation of strongly enhanced extended red emission (ERE) by interstellar dust in H2 photodissociation zones. The ERE has been attributed to photoluminescence by hydrogenated amorphous carbon (HAC). We are demonstrating that exposure to thermally dissociated atomic hydrogen will restore the photoluminescence efficiency of previously annealed HAC. Also, pure amorphous carbon (AC), not previously photoluminescent, can be induced to photoluminesce by exposure to atomic hydrogen. This conversion of AC into HAC is greatly enhanced by the presence of UV irradiation. The presence of dense, warm atomic hydrogen and a strong UV radiation field are characteristic environmental properties of H2 dissociation zones. Our results lend strong support to the HAC photoluminescence explanation for ERE.

  3. THE BALMER-DOMINATED BOW SHOCK AND WIND NEBULA STRUCTURE OF {gamma}-RAY PULSAR PSR J1741-2054

    SciTech Connect

    Romani, Roger W.; Shaw, Michael S.; Camilo, Fernando; Cotter, Garret; Sivakoff, Gregory R. E-mail: msshaw@stanford.ed

    2010-12-01

    We have detected an H{alpha} bow shock nebula around PSR J1741-2054, a pulsar discovered through its GeV {gamma}-ray pulsations. The pulsar is only {approx}1.''5 behind the leading edge of the shock. Optical spectroscopy shows that the nebula is non-radiative, dominated by Balmer emission. The H{alpha} images and spectra suggest that the pulsar wind momentum is equatorially concentrated and implies a pulsar space velocity {approx}150 km s{sup -1}, directed 15{sup 0} {+-} 10{sup 0} out of the plane of the sky. The complex H{alpha} profile indicates that different portions of the post-shock flow dominate line emission as gas moves along the nebula and provide an opportunity to study the structure of this unusual slow non-radiative shock under a variety of conditions. CXO ACIS observations reveal an X-ray pulsar wind nebula within this nebula, with a compact {approx}2.''5 equatorial structure and a trail extending several arcminutes behind. Together these data support a close ({<=}0.5 kpc) distance, a spin geometry viewed edge-on, and highly efficient {gamma}-ray production for this unusual, energetic pulsar.

  4. Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends

    SciTech Connect

    Kirby S. Chapman; Amar Patil

    2007-06-30

    Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes the drawbacks inherent in each fuel type. Objectives of the current study were to evaluate the feasibility of using blends of hydrogen and natural gas as a fuel for conventional natural gas engines. The experiment and data analysis included evaluation of engine performance, efficiency, and emissions along with detailed in-cylinder measurements of key physical parameters. This provided a detailed knowledge base of the impact of using hydrogen/natural gas blends. A four-stroke, 4.2 L, V-6 naturally aspirated natural gas engine coupled to an eddy current dynamometer was used to measure the impact of hydrogen/natural gas blends on performance, thermodynamic efficiency and exhaust gas emissions

  5. Removing hydrogen sulfide from geothermal gases: hypochlorite process reduces hydrogen sulfide emissions to acceptable levels. NTIS tech note

    SciTech Connect

    Not Available

    1981-10-01

    This citation summarizes a one-page announcement of technology available for utilization. A hypochlorite process has been proposed as an alternative to other methods for the removal of hydrogen sulfide from the exhaust gases of geothermal powerplants. An electrolytically-generated sodium hypochlorite solution converts the hydrogen sulfide to water, salt, and sulfur. The hypochlorite process appears to be less expensive than competing processes for most of the cases studied. ...FOR ADDITIONAL INFORMATION: Detailed information about the technology described may be obtained by ordering the NTIS report, order number: DOE/ER/1092-T7, price code: PC A03.

  6. Emission-Line Variability in the Iron Star XX Orphiuchus Over the Past Decade

    NASA Astrophysics Data System (ADS)

    Pugh, Bryan; Walter, D. K.; Howell, S. B.; Cash, J.

    2013-01-01

    We present the results of an analysis of nine years of spectra taken with the Coudé Feed telescope at KPNO of the Iron Star XX Oph. In addition to numerous iron lines, other metals such as Ti and the hydrogen Balmer series are seen in emission, while still others such as the H and K lines of Ca II are in absorption. Our study covers the years 2003 to 2012 and includes an episode in 2004 where photometry from the AAVSO shows a 1.5 magnitude drop in brightness as discussed in Cool et.al. (2005, PASP, 117, 462). Beginning in 2005 and continuing to the present, our data show Balmer lines with P-Cygni profiles , where the strength of the absorption components generally increase over time while the emission components are diminished. We discuss our results in comparison to the model of Howell et.al. (2009 PASAP, 121, 16) of AS 325, a similar iron emission-line star in a binary system. Support for this work was provided by the NSF PAARE program to South Carolina State University under award AST-0750814. We thank the director of KPNO for his generous allocation of telescope time to this project over the years.

  7. Remote sensing and geologic studies of the Balmer-Kapteyn region of the Moon

    NASA Astrophysics Data System (ADS)

    Hawke, B. Ray; Gillis, J. J.; Giguere, T. A.; Blewett, D. T.; Lawrence, D. J.; Lucey, P. G.; Smith, G. A.; Spudis, P. D.; Taylor, G. Jeffrey

    2005-06-01

    The Balmer-Kapteyn (B-K) region is located just east of Mare Fecunditatis on the east limb of the Moon. It is centered on the Balmer-Kapteyn basin, a pre-Nectarian impact structure that exhibits two rings, approximately 225 km and 450 km in diameter. Clementine multispectral images and Lunar Prospector (LP) gamma-ray spectrometer (GRS) data were used to investigate the composition, age, and origin of geologic units in the region. A major expanse of cryptomare was mapped within the B-K basin. Spectral and chemical data obtained for dark-haloed craters (DHCs) established that these impact craters excavated mare basalt from beneath higher-albedo, highland-rich surface units. The buried basalts exposed by DHCs in the region are dominated by low-titanium mare basalts. The fresh DHC FeO values (15.0-15.7 wt.%) that best represent those of buried mare basalts are well within the range of values exhibited by high-alumina mare basalts. While most cryptomare deposits occur beneath surfaces that range in age from Imbrian to Nectarian, it is possible that some mare flows were emplaced during pre-Nectarian time. Most cryptomare deposits in the B-K region were formed by the contamination of mare surfaces by highland-rich distal ejecta from surrounding impact craters. These Balmer-type cryptomare deposits are usually associated with light plains units. Major LP-GRS FeO enhancements are associated with cryptomaria in the Balmer-Kapteyn, Lomonosov-Fleming, Schiller-Schickard, and Mendel-Rydberg regions.

  8. Zero Emissions Hydrogen Production by Fluidized Bed Catalytic Decomposition of Methane

    NASA Astrophysics Data System (ADS)

    Ammendola, P.; Chirone, R.; Ruoppolo, G.

    The present paper deals with the strategic field of production of clean fuels with very low to zero emissions. A two stage fluidized bed process for catalytic decomposition of methane has been investigated. Firstly, the fluidized bed has been operated for the thermo-catalytic decomposition (TCD) of methane to produce hydrogen and solid carbon, which deposited on the catalyst. Secondly, the carbon oxy-combustion has been carried out to regenerate the catalyst producing a separated CO2 stream candidate to be directly fed to a sequestration unit. Experiments have been carried out in a laboratory scale bubbling fluidized bed reactor (26mm ill) using a home-made copper dispersed on γ-alumina as catalyst operated at 800°C. The carbon oxy-combustion regeneration strategy have been compared to the carbon combustion one on the basis of the efficiency of carbon removal and the performance ofregenerated catalyst with respect to the TCD process. The effect of multiple cycles of decomposition and regeneration steps has been also quantified. A reasonable cyclic process has been simulated switching between two different feeds, the first containing CH4 and the second containing the regeneration stream. Experimental activity confirmed the possibility ofproducing a CO2 stream that can be finalized to a sequestration unit but also indicated some drawbacks related to the oxy-combustion regeneration strategy which affect the production of COx species during the methane decomposition stage.

  9. Second Epoch Hubble Space Telescope Observations of Kepler's Supernova Remnant: The Proper Motions of Balmer Filaments

    NASA Astrophysics Data System (ADS)

    Sankrit, Ravi; Raymond, John C.; Blair, William P.; Long, Knox S.; Williams, Brian J.; Borkowski, Kazimierz J.; Patnaude, Daniel J.; Reynolds, Stephen P.

    2016-01-01

    We report on the proper motions of Balmer-dominated filaments in Kepler’s supernova remnant using high resolution images obtained with the Hubble Space Telescope at two epochs separated by about 10 years. We use the improved proper motion measurements and revised values of shock velocities to derive a distance to Kepler of {5.1}-0.7+0.8 kpc. The main shock around the northern rim of the remnant has a typical speed of 1690 km s-1 and is encountering material with densities of about 8 cm-3. We find evidence for the variation of shock properties over small spatial scales, including differences in the driving pressures as the shock wraps around a curved cloud surface. We find that the Balmer filaments ahead of the ejecta knot on the northwest boundary of the remnant are becoming fainter and more diffuse. We also find that the Balmer filaments associated with circumstellar material in the interior regions of the remnant are due to shocks with significantly lower velocities and that the brightness variations among these filaments trace the density distribution of the material, which may have a disk-like geometry. Based on observations made with the Hubble Space Telescope.

  10. Dynamic flux chamber measurements of hydrogen sulfide emission rate from a quiescent surface--A computational evaluation.

    PubMed

    Prata, Ademir A; Santos, Jane M; Beghi, Sandra P; Fernandes, Isabella F; Vom Marttens, Lya L C; Pereira Neto, Leovegildo I; Martins, Ramon S; Reis, Neyval C; Stuetz, Richard M

    2016-03-01

    Enclosure devices have been studied and used for research purposes and practical applications in order to measure the emission rate of odorous pollutants from quiescent liquid surfaces to atmosphere. However, important questions remain about the interference of these measuring devices on the actual emission rate. The main concern regarding the use of a flux chamber is the fact that odorous compounds can accumulate into the chamber and yield gas-phase concentration increase inside the equipment, which causes a reduction of the emission rate during the measurement and thus gives an inaccurate local emission rate. Furthermore, the fluid flow inside the chamber does not reproduce the atmospheric boundary layer flow. This study applied the Computational Fluid Dynamics (CFD) technique in order to investigate the influence of the fluid flow features inside a flux chamber on the measured hydrogen sulfide emission rate at quiescent liquid surfaces. The flux chamber design and operational conditions are those supported by the United States Environmental Protection Agency (US EPA). The results show that the US EPA flux chamber presents a fairly well mixed air phase. However, a trend to stagnation and hydrogen sulfide accumulation near chamber walls was detected in the computational simulation, which also indicated that the positioning of the sampling tube in relation to the inlet orifices may lead to deviations in the measurement results. CFD results showed that the wall shear and concentration gradients spatially vary at the gas-liquid interface, and friction velocity inside the chamber does not match typical values of atmospheric flow. PMID:26741548

  11. Measurements of neutral density profiles using a deuterium Balmer-alpha diagnostic in the C-2 FRC plasma

    SciTech Connect

    Gupta, Deepak K.; Deng, B. H.; Knapp, K.; Sun, X.; Thompson, M. C.

    2012-10-15

    In C-2 field-reversed configuration (FRC) device, low neutral density outside the FRC separatrix is required to minimize the charge exchange loss of fast particles. Titanium gettering is used in C-2 to reduce the wall recycling and keep the neutral density low in plasma edge. The measurements of neutral density radial profile are desirable to understand the plasma recycling and the effects of titanium gettering. These measurements are also needed to study the interaction of neutral beams with FRC plasma and confinement of fast ions. Diagnostic based on absolute deuterium Balmer-alpha (D-alpha) radiation measurements is developed and deployed on C-2 device to measure the radial profile of neutral density. Simultaneous measurements of electron density and temperature are done using CO{sub 2} interferometer, Thomson scattering, and triple probes diagnostics along with absolute D-alpha radiation. Abel inversion was performed to get the time dependent radial profile of the local D-alpha emission density. Neutral density profiles are obtained under different machine conditions of titanium deposition.

  12. Two-center effect on low-energy electron emission in collisions of 1-MeV/u bare ions with atomic hydrogen, molecular hydrogen, and helium. I. Atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Tribedi, Lokesh C.; Richard, P.; Gulyás, L.; Rudd, M. E.; Moshammer, R.

    2001-06-01

    We have investigated ionization mechanisms in fast ion-atom collisions by measuring the low-energy electron emission cross sections in a pure three-body collision involving bare carbon ions (v=6.35 a.u.) colliding with atomic hydrogen targets. The measurements have also been extended to molecular hydrogen and helium targets. In this paper we provide the energy and angular distributions of double differential cross sections of low-energy electron emission for atomic hydrogen targets. The Slevin rf source with a high degree of dissociation was used to produce the atomic H target. It is found that the two-center effect has a major influence on the observed large forward-backward angular asymmetry. A detailed comparison is presented with calculations based on the continuum distorted-wave (CDW) and CDW-EIS (eikonal initial-state) approximations. Both the continuum distorted-wave calculations provide a very good understanding of the data, whereas the first Born calculation predicts almost symmetric forward-backward distributions that do not agree with the data. The two-center effect is slightly better represented by the CDW calculations compared to the CDW-EIS calculation. The total cross sections are, however, in good agreement with the theories used. The results for molecular hydrogen and helium will be discussed in the following paper.

  13. JET-SHOCKED H{sub 2} AND CO IN THE ANOMALOUS ARMS OF MOLECULAR HYDROGEN EMISSION GALAXY NGC 4258

    SciTech Connect

    Ogle, P. M.; Lanz, L.; Appleton, P. N.

    2014-06-20

    We present a Spitzer Infrared Spectrograph map of H{sub 2} emission from the nearby galaxy NGC 4258 (Messier 106). The H{sub 2} emission comes from 9.4 ± 0.4 × 10{sup 6} M {sub ☉} of warm molecular hydrogen heated to 240-1040 K in the inner anomalous arms, a signature of jet interaction with the galaxy disk. The spectrum is that of a molecular hydrogen emission galaxy (MOHEG), with a large ratio of H{sub 2} over 7.7 μm polycyclic aromatic hydrocarbon emission (0.37), characteristic of shocked molecular gas. We find close spatial correspondence between the H{sub 2} and CO emission from the anomalous arms. Our estimate of cold molecular gas mass based on CO emission is 10 times greater than our estimate of 1.0 × 10{sup 8} M {sub ☉} based on dust emission. We suggest that the X {sub CO} value is 10 times lower than the Milky Way value because of high kinetic temperature and enhanced turbulence. The H{sub 2} disk has been overrun and is being shocked by the jet cocoon, and much of the gas originally in the disk has been ejected into the galaxy halo in an X-ray hot outflow. We measure a modest star formation rate of 0.08 M {sub ☉} yr{sup –1} in the central 3.4 kpc{sup 2} that is consistent with the remaining gas surface density.

  14. In2O3 Nanotower Hydrogen Gas Sensors Based on Both Schottky Junction and Thermoelectronic Emission

    NASA Astrophysics Data System (ADS)

    Zheng, Zhao Qiang; Zhu, Lian Feng; Wang, Bing

    2015-07-01

    Indium oxide (In2O3) tower-shaped nanostructure gas sensors have been fabricated on Cr comb-shaped interdigitating electrodes with relatively narrower interspace of 1.5 μm using thermal evaporation of the mixed powders of In2O3 and active carbon. The Schottky contact between the In2O3 nanotower and the Cr comb-shaped interdigitating electrode forms the Cr/In2O3 nanotower Schottky diode, and the corresponding temperature-dependent I- V characteristics have been measured. The diode exhibits a low Schottky barrier height of 0.45 eV and ideality factor of 2.93 at room temperature. The In2O3 nanotower gas sensors have excellent gas-sensing characteristics to hydrogen concentration ranging from 2 to 1000 ppm at operating temperature of 120-275 °C, such as high response (83 % at 240 °C to 1000 ppm H2), good selectivity (response to H2, CH4, C2H2, and C3H8), and small deviation from the ideal value of power exponent β (0.48578 at 240 °C). The sensors show fine long-term stability during exposure to 1000 ppm H2 under operating temperature of 240 °C in 30 days. Lots of oxygen vacancies and chemisorbed oxygen ions existing in the In2O3 nanotowers according to the x-ray photoelectron spectroscopy (XPS) results, the change of Schottky barrier height in the Cr/In2O3 Schottky junction, and the thermoelectronic emission due to the contact between two In2O3 nanotowers mainly contribute for the H2 sensing mechanism. The growth mechanism of the In2O3 nanotowers can be described to be the Vapor-Solid (VS) process.

  15. Ultralow field emission from thinned, open-ended, and defected carbon nanotubes by using microwave hydrogen plasma processing

    NASA Astrophysics Data System (ADS)

    Deng, Jian-Hua; Cheng, Lin; Wang, Fan-Jie; Yu, Bin; Li, Guo-Zheng; Li, De-Jun; Cheng, Guo-An

    2015-01-01

    Ultralow field emission is achieved from carbon nanotubes (CNTs) by using microwave hydrogen plasma processing. After the processing, typical capped CNT tips are removed, with thinned, open-ended, and defected CNTs left. Structural analyses indicate that the processed CNTs have more SP3-hybridized defects as compared to the pristine ones. The morphology of CNTs can be readily controlled by adjusting microwave powers, which change the shape of CNTs by means of hydrogen plasma etching. Processed CNTs with optimal morphology are found to have an ultralow turn-on field of 0.566 V/μm and threshold field of 0.896 V/μm, much better than 0.948 and 1.559 V/μm of the as-grown CNTs, respectively. This improved FE performance is ascribed to the structural changes of CNTs after the processing. The thinned and open-ended shape of CNTs can facilitate electron tunneling through barriers and additionally, the increased defects at tube walls can serve as new active emission sites. Furthermore, our plasma processed CNTs exhibit excellent field emission stability at a large emission current density of 10.36 mA/cm2 after being perfectly aged, showing promising prospects in applications as high-performance vacuum electron sources.

  16. Compound specific carbon and hydrogen stable isotope analyses of volatile organic compounds in various emissions of combustion processes.

    PubMed

    Vitzthum von Eckstaedt, Christiane D; Grice, Kliti; Ioppolo-Armanios, Marisa; Kelly, David; Gibberd, Mark

    2012-11-01

    This study presents carbon (δ(13)C) and hydrogen (δD) isotope values of volatile organic compounds (VOCs) in various emission sources using thermal desorption-gas chromatography-isotope ratio mass spectrometry (TD-GC-irMS). The investigated VOCs ranged from C6 to C10. Samples were taken from (i) car exhaust emissions as well as from plant combustion experiments of (ii) various C3 and (iii) various C4 plants. We found significant differences in δ values of analysed VOCs between these sources, e.g. δ(13)C of benzene ranged between (i) -21.7 ± 0.2 ‰, (ii) -27.6 ± 1.6 ‰ and (iii) -16.3 ± 2.2 ‰, respectively and δD of benzene ranged between (i) -73 ± 13 ‰, (ii) -111 ± 10 ‰ and (iii) -70 ± 24 ‰, respectively. Results of VOCs present in investigated emission sources were compared to values from the literature (aluminium refinery emission). All source groups could be clearly distinguished using the dual approach of δ(13)C and δD analysis. The results of this study indicate that the correlation of compound specific carbon and hydrogen isotope analysis provides the potential for future research to trace the fate and to determine the origin of VOCs in the atmosphere using thermal desorption compound specific isotope analysis. PMID:22921436

  17. Mapping the Spatial Distribution of Molecular Hydrogen and PAH emission in Nearby Galaxies with the Spitzer Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Brunner, Gregory; Dufour, R. J.; Sheth, K.; Armus, L.; Schinnerer, E.; Vogel, S.; Wolfire, M.

    2007-12-01

    We have embarked on an archival program to map the spatial distribution of pure rotational molecular hydrogen (H2) line emission and polycyclic aromatic hydrogen (PAH) emission (from the 6.2, 7.7, 8.6, 11.3, 12.7, and 17.1 micron PAH features) in nearby galaxies using spatially resolved Spitzer IRS spectra acquired as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) and other Spitzer programs. We present maps of the H2 and PAH emission for several galaxies (M51, M95, and NGC 3521). We compare the emission distributions in order to understand how H2, PAHs, and ionized gas are spatially correlated across dynamically distinct regions in nearby galaxies. This work is based on observations and archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by both AURA grant GO10822.1 and an award issued by JPL/Caltech to Rice University.

  18. Evaluation of a Hydrogen Fuel Cell Powered Blended-Wing-Body Aircraft Concept for Reduced Noise and Emissions

    NASA Technical Reports Server (NTRS)

    Guynn, Mark D.; Freh, Joshua E.; Olson, Erik D.

    2004-01-01

    This report describes the analytical modeling and evaluation of an unconventional commercial transport aircraft concept designed to address aircraft noise and emission issues. A blended-wing-body configuration with advanced technology hydrogen fuel cell electric propulsion is considered. Predicted noise and emission characteristics are compared to a current technology conventional configuration designed for the same mission. The significant technology issues which have to be addressed to make this concept a viable alternative to current aircraft designs are discussed. This concept is one of the "Quiet Green Transport" aircraft concepts studied as part of NASA's Revolutionary Aerospace Systems Concepts (RASC) Program. The RASC Program was initiated to develop revolutionary concepts that address strategic objectives of the NASA Enterprises, such as reducing aircraft noise and emissions, and to identify advanced technology requirements for the concepts.

  19. Evaluation of an Aircraft Concept With Over-Wing, Hydrogen-Fueled Engines for Reduced Noise and Emissions

    NASA Technical Reports Server (NTRS)

    Guynn, Mark D.; Olson, Erik D.

    2002-01-01

    This report describes the analytical modeling and evaluation of an unconventional commercial transport aircraft concept designed to address aircraft noise and emission issues. A strut-braced wing configuration with overwing, ultra-high bypass ratio, hydrogen fueled turbofan engines is considered. Estimated noise and emission characteristics are compared to a conventional configuration designed for the same mission and significant benefits are identified. The design challenges and technology issues which would have to be addressed to make the concept a viable alternative to current aircraft designs are discussed. This concept is one of the "Quiet Green Transport" aircraft concepts studied as part of NASA's Revolutionary Aerospace Systems Concepts (RASC) Program. The RASC Program seeks to develop revolutionary concepts that address strategic objectives of the NASA Enterprises, such as reducing aircraft noise and emissions, and to identify enabling advanced technology requirements for the concepts.

  20. Emissions of ammonia, hydrogen sulfide, and odor before, during, and after slurry removal from a deep-pit swine finisher.

    PubMed

    Hoff, Steven J; Bundy, Dwaine S; Nelson, Minda A; Zelle, Brian C; Jacobson, Larry D; Heber, Albert J; Ni, Jinqin; Zhang, Yuanhui; Koziel, Jacek A; Beasley, David B

    2006-05-01

    It is a common practice in the midwestern United States to raise swine in buildings with under-floor slurry storage systems designed to store manure for up to one year. These so-called "deep-pit" systems are a concentrated source for the emissions of ammonia (NH3), hydrogen sulfide (H2S), and odors. As part of a larger six-state research effort (U.S. Department of Agriculture-Initiative for Future Agriculture and Food Systems Project, "Aerial Pollutant Emissions from Confined Animal Buildings"), realtime NH3 and H2S with incremental odor emission data were collected for two annual slurry removal events. For this study, two 1000-head deep-pit swine finishing facilities in central Iowa were monitored with one-year storage of slurry maintained in a 2.4 m-deep concrete pit (or holding tank) below the animal-occupied zone. Results show that the H2S emission, measured during four independent slurry removal events over two years, increased by an average of 61.9 times relative to the before-removal H2S emission levels. This increase persisted during the agitation process of the slurry that on average occurred over an 8-hr time period. At the conclusion of slurry agitation, the H2S emission decreased by an average of 10.4 times the before-removal emission level. NH3 emission during agitation increased by an average of 4.6 times the before-removal emission level and increased by an average of 1.5 times the before-removal emission level after slurry removal was completed. Odor emission increased by a factor of 3.4 times the before-removal odor emission level and decreased after the slurry-removal event by a factor of 5.6 times the before-removal emission level. The results indicate that maintaining an adequate barn ventilation rate regardless of animal comfort demand is essential to keeping gas levels inside the barn below hazardous levels. PMID:16739794

  1. Balmer profiles in the geocorona and interstellar space. I - Asymmetries due to fine structure

    NASA Technical Reports Server (NTRS)

    Chamberlain, Joseph W.

    1987-01-01

    While the Doppler profiles of Balmer-alpha and -beta are in principle analyzable in order to derive orbital data concerning both escaping and satellite geocoronal particles, interpretations are in practice hampered by a lack of understanding of profile properties apart from such geocoronal features as an asymmetry, caused by the absence of escape velocity-exceeding, downward-directed particles. Attention is accordingly given to the profiles of H atoms which, while emitting radiation from a complete Maxwellian distribution, also exhibit an H-alpha fine structure-generated asymmetry which is a predictable function of the excitation mechanism.

  2. Balmer-beta line asymmetry characteristics in a high pressure, microwave-produced argon plasma.

    PubMed

    Palomares, J M; Torres, J; Gigosos, M A; van der Mullen, J J A M; Gamero, A; Sola, A

    2009-11-01

    This paper presents a study on the asymmetry of the Balmer H(beta) profile in plasmas produced by microwaves at high pressure with the help of some functions of asymmetry for the whole profile, as well as by means of some specific parameters characterizing only its central dip. The study shows how this asymmetry--very low in our case--depends on the electron density and flux of gases and how the existence of inhomogeneities in the plasma can affect the shape and symmetry of this line. Also, limitations on the determination of the asymmetry are pointed out and the use of this profile for plasma diagnosis is discussed. PMID:19891830

  3. MOLECULAR HYDROGEN EMISSION FROM THE BOUNDARIES OF THE TAURUS MOLECULAR CLOUD

    SciTech Connect

    Goldsmith, Paul F.; Velusamy, Thangasamy; Li Di; Langer, William D.

    2010-06-01

    We report Spitzer Space Telescope observations of the four lowest rotational transitions of H{sub 2} in three portions of the boundary of the Taurus molecular cloud. Emission in the two lowest transitions, S(0) and S(1), was detected in almost all pointing directions, while the S(2) and S(3) lines were marginally detected only after further averaging of data. The widespread detection of lines coming from levels 510 K and 1016 K above the molecular ground state is indicative of gas at a temperature of at least 200 K containing column densities (1-5) x 10{sup 18} cm{sup -2} of H{sub 2}. For the region with the simplest geometry, we have used the Meudon PDR code to model the chemistry, radiative transfer, and excitation of molecular hydrogen. We conclude that models with acceptable values of the UV interstellar radiation field can reproduce the amount of H{sub 2} in the lowest excited state, but cannot account for the degree of excitation of the H{sub 2}. The unexpectedly high degree of excitation of the H{sub 2} in the boundary layer of a molecular cloud, which cannot be explained by the presence of stellar sources, points to an enhanced heating rate which may be the result of, e.g., dissipation of turbulence. We have in one boundary region been able to obtain the ortho-to-para ratio (OPR) for H{sub 2}, which by modeling and possible detection of the S(2) and S(3) lines has a range 1.0 {>=} OPR {>=} 0.15, although this result must be treated with caution. The fact that the ortho-to-para ratio is lower than that expected for equilibrium at the gas kinetic temperature may be indicative of circulation of material from cold, purely molecular regions into the boundary layer, possibly due to turbulent diffusion. The explanation of these data may thus be suggestive of processes that are having a significant effect on the structure and evolution of molecular clouds and the star formation that takes place within them.

  4. Molecular Hydrogen Emission from the Boundaries of the Taurus Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Goldsmith, Paul F.; Velusamy, Thangasamy; Li, Di; Langer, William D.

    2010-06-01

    We report Spitzer Space Telescope observations of the four lowest rotational transitions of H2 in three portions of the boundary of the Taurus molecular cloud. Emission in the two lowest transitions, S(0) and S(1), was detected in almost all pointing directions, while the S(2) and S(3) lines were marginally detected only after further averaging of data. The widespread detection of lines coming from levels 510 K and 1016 K above the molecular ground state is indicative of gas at a temperature of at least 200 K containing column densities (1-5) × 1018 cm-2 of H2. For the region with the simplest geometry, we have used the Meudon PDR code to model the chemistry, radiative transfer, and excitation of molecular hydrogen. We conclude that models with acceptable values of the UV interstellar radiation field can reproduce the amount of H2 in the lowest excited state, but cannot account for the degree of excitation of the H2. The unexpectedly high degree of excitation of the H2 in the boundary layer of a molecular cloud, which cannot be explained by the presence of stellar sources, points to an enhanced heating rate which may be the result of, e.g., dissipation of turbulence. We have in one boundary region been able to obtain the ortho-to-para ratio (OPR) for H2, which by modeling and possible detection of the S(2) and S(3) lines has a range 1.0 >= OPR >= 0.15, although this result must be treated with caution. The fact that the ortho-to-para ratio is lower than that expected for equilibrium at the gas kinetic temperature may be indicative of circulation of material from cold, purely molecular regions into the boundary layer, possibly due to turbulent diffusion. The explanation of these data may thus be suggestive of processes that are having a significant effect on the structure and evolution of molecular clouds and the star formation that takes place within them.

  5. Hydrogenation of polycyclic aromatic hydrocarbons as a factor affecting the cosmic 6.2 micron emission band

    NASA Technical Reports Server (NTRS)

    Beegle, L. W.; Wdowiak, T. J.; Harrison, J. G.

    2001-01-01

    While many of the characteristics of the cosmic unidentified infrared (UIR) emission bands observed for interstellar and circumstellar sources within the Milky Way and other galaxies, can be best attributed to vibrational modes of the variants of the molecular family known as polycyclic aromatic hydrocarbons (PAH), there are open questions that need to be resolved. Among them is the observed strength of the 6.2 micron (1600 cm(-1)) band relative to other strong bands, and the generally low strength for measurements in the laboratory of the 1600 cm(-1) skeletal vibration band of many specific neutral PAH molecules. Also, experiments involving laser excitation of some gas phase neutral PAH species while producing long lifetime state emission in the 3.3 micron (3000 cm(-1)) spectral region, do not result in significant 6.2 micron (1600 cm(-1)) emission. A potentially important variant of the neutral PAH species, namely hydrogenated-PAH (H(N)-PAH) which exhibit intriguing spectral correlation with interstellar and circumstellar infrared emission and the 2175 A extinction feature, may be a factor affecting the strength of 6.2 micron emission. These species are hybrids of aromatic and cycloalkane structures. Laboratory infrared absorption spectroscopy augmented by density function theory (DFT) computations of selected partially hydrogenated-PAH molecules, demonstrates enhanced 6.2 micron (1600 cm(-1)) region skeletal vibration mode strength for these molecules relative to the normal PAH form. This along with other factors such as ionization or the incorporation of nitrogen or oxygen atoms could be a reason for the strength of the cosmic 6.2 micron (1600 cm(-1)) feature.

  6. Interaction of toluene with two-color asymmetric laser fields: Controlling the directional emission of molecular hydrogen fragments

    NASA Astrophysics Data System (ADS)

    Kaziannis, S.; Kotsina, N.; Kosmidis, C.

    2014-09-01

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H2+ and H3+ fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH3- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H2+, H3+ species.

  7. Interaction of toluene with two-color asymmetric laser fields: controlling the directional emission of molecular hydrogen fragments.

    PubMed

    Kaziannis, S; Kotsina, N; Kosmidis, C

    2014-09-14

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H2(+) and H3(+) fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH3- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H2(+), H3(+) species. PMID:25217928

  8. Interaction of toluene with two-color asymmetric laser fields: Controlling the directional emission of molecular hydrogen fragments

    SciTech Connect

    Kaziannis, S.; Kotsina, N.; Kosmidis, C.

    2014-09-14

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H{sub 2}{sup +} and H{sub 3}{sup +} fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH{sub 3}- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H{sub 2}{sup +}, H{sub 3}{sup +} species.

  9. Sodium tetraborate decahydrate (borax) treatment reduces hydrogen sulfide emissions and correlates with a decrease in the sulfate reducing bacteria population of stored swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emission of odorous and toxic gases from stored livestock manure is well documented, and poses a serious health risk to farmers and livestock. Hydrogen sulfide emissions have been sharply rising with more intensive livestock production and are of particular concern due to its acute toxicity. Num...

  10. Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows.

    PubMed

    Lopes, J C; de Matos, L F; Harper, M T; Giallongo, F; Oh, J; Gruen, D; Ono, S; Kindermann, M; Duval, S; Hristov, A N

    2016-07-01

    The objective of this crossover experiment was to investigate the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission, methane isotopic composition, and rumen fermentation and microbial profile in lactating dairy cows. The experiment involved 6 ruminally cannulated late-lactation Holstein cows assigned to 2 treatments: control and 3NOP (60 mg/kg of feed dry matter). Compared with the control, 3NOP decreased methane emission by 31% and increased hydrogen emission from undetectable to 1.33 g/d. Methane emissions per kilogram of dry matter intake and milk yield were also decreased 34% by 3NOP. Milk production and composition were not affected by 3NOP, except milk fat concentration was increased compared with the control. Concentrations of total VFA and propionate in ruminal fluid were not affected by treatment, but acetate concentration tended to be lower and acetate-to-propionate ratio was lower for 3NOP compared with the control. The 3NOP decreased the molar proportion of acetate and increase those of propionate, butyrate, valerate, and isovalerate. Deuterium-to-hydrogen ratios of methane and the abundance of (13)CH3D were similar between treatments. Compared with the control, minor (4‰) depletion in the (13)C/(12)C ratio was observed for 3NOP. Genus composition of methanogenic archaea (Methanobrevibacter, Methanosphaera, and Methanomicrobium) was not affected by 3NOP, but the proportion of methanogens in the total cell counts tended to be decreased by 3NOP. Prevotella spp., the predominant bacterial genus in ruminal contents in this experiment, was also not affected by 3NOP. Compared with the control, Ruminococcus and Clostridium spp. were decreased and Butyrivibrio spp. was increased by 3NOP. This experiment demonstrated that a substantial inhibition of enteric methane emission by 3NOP in dairy cows was accompanied with increased hydrogen emission and decreased acetate-to-propionate ratio; however, neither an effect on rumen

  11. Hydrogen Emission Line n110 rarr n109: Detection at 5009 Megahertz in Galactic H II Regions.

    PubMed

    Höglund, B; Mezger, P G

    1965-10-15

    The hydrogen emission line n(1l0) --> n(109) at the frequency 5009 megahertz which was predicted by Kardashev has been detected in M 17, Orion, and nine other galactic H II regions with the 42.7-m (140-foot) telescope and a 20-channel receiver at the National Radio Astronomy Observatory. The measured product of the half-power width of the line times the ratio of line-to-continuum brightness temperature is larger than that predicted by Kardashev's theory. The radial velocity obtained for M 17 and Orion agrees well with optical measurements. The search for a similar line of excited helium was without success. PMID:17742362

  12. Effect of cumulated dose on hydrogen emission from polyethylene irradiated under oxidative atmosphere using gamma rays and ion beams

    NASA Astrophysics Data System (ADS)

    Ferry, M.; Pellizzi, E.; Boughattas, I.; Fromentin, E.; Dauvois, V.; de Combarieu, G.; Coignet, P.; Cochin, F.; Ngono-Ravache, Y.; Balanzat, E.; Esnouf, S.

    2016-01-01

    This work reports the effect of very high doses, up to 10 MGy, on the H2 emission from high density polyethylene (HDPE) irradiated with gamma rays and ion beams, in the presence of oxygen. This was obtained through a two-step procedure. First, HDPE films were pre-aged, at different doses, using either gamma rays or ion beams. In the second step, the pre-aged samples were irradiated in closed glass ampoules for gas quantification, using the same beam type as for pre-ageing. The hydrogen emission rate decreases when dose increases for both gamma rays and ion beams. However, the decreasing rate appears higher under gamma rays than under ion beam irradiations and this is assigned to a lesser oxidation level under the latter. Herein, we show the effectiveness of the radiation-induced defects scavenging effect under oxidative atmosphere, under low and high excitation densities.

  13. Spatially Resolved Spectroscopy of a Balmer-dominated Shock in the Cygnus Loop: An Extremely Thin Cosmic-Ray Precursor?

    NASA Astrophysics Data System (ADS)

    Katsuda, Satoru; Maeda, Keiichi; Ohira, Yutaka; Yatsu, Yoichi; Mori, Koji; Aoki, Wako; Morihana, Kumiko; Raymond, John C.; Ghavamian, Parviz; Lee, Jae-Joon; Shimoda, Jiro; Yamazaki, Ryo

    2016-03-01

    We present high-resolution long-slit spectroscopy of a Balmer-dominated shock in the northeastern limb of the Cygnus Loop with the Subaru high dispersion spectrograph. By setting the slit angle along the shock normal, we investigate variations of the flux and profile of the Hα line from preshock to postshock regions with a spatial resolution of ˜4 × 1015 cm. The Hα line profile can be represented by a narrow (28.9 ± 0.7 km s-1) Gaussian in a diffuse region ahead of the shock, i.e., a photoionization precursor, and narrow (33.1 ± 0.2 km s-1) plus broad (130-230 km s-1) Gaussians at the shock itself. We find that the width of the narrow component abruptly increases up to 33.1 ± 0.2 km s-1, or 38.8 ± 0.4 km s-1 if we eliminate projected emission originating from the photoionization precursor, in an unresolved thin layer (≲4 × 1015 cm at a distance of 540 pc) at the shock. We show that the sudden broadening can be best explained by heating via damping of Alfvén waves in a thin cosmic-ray (CR) precursor, although other possibilities are not fully ruled out. The thickness of the CR precursor in the Cygnus Loop (a soft gamma-ray emitter) is an order of magnitude thinner than that in Tycho’s Knot g (a hard gamma-ray emitter), which may be caused by the different energy distribution of accelerated particles between the two sources. In this context, systematic studies might reveal a positive correlation between the thickness of the CR precursor and the hardness of the CR energy distribution.

  14. Hydrogen stable isotopic constraints on methane emissions from oil and gas extraction in the Colorado Front Range, USA

    NASA Astrophysics Data System (ADS)

    Townsend-Small, A.; Botner, E. C.; Jimenez, K.; Blake, N. J.; Schroeder, J.; Meinardi, S.; Barletta, B.; Simpson, I. J.; Blake, D. R.; Flocke, F. M.; Pfister, G.; Bon, D.; Crawford, J. H.

    2015-12-01

    The climatic implications of a shift from oil and coal to natural gas depend on the magnitude of fugitive emissions of methane from the natural gas supply chain. Attempts to constrain methane emissions from natural gas production regions can be confounded by other sources of methane. Here we demonstrate the utility of stable isotopes, particularly hydrogen isotopes, for source apportionment of methane emissions. The Denver, Colorado area is home to a large oil and gas field with both conventional oil and gas wells and newer hydraulic fracturing wells. The region also has a large metropolitan area with several landfills and a sizable cattle population. As part of the DISCOVER-AQ and FRAPPE field campaigns in summer 2014, we collected three types of canister samples for analysis of stable isotopic composition of methane: 1), samples from methane sources; 2), samples from two stationary ground sites, one in the Denver foothills, and one in an oil and gas field; and 3), from the NCAR C-130 aircraft in samples upwind and downwind of the region. Our results indicate that hydrogen isotope ratios are excellent tracers of sources of methane in the region, as we have shown previously in California and Texas. Use of carbon isotope ratios is complicated by the similarity of natural gas isotope ratios to that of background methane. Our results indicate that, despite the large amount of natural gas production in the region, biological sources such as cattle feedlots and landfills account for at least 50% of total methane emissions in the Front Range. Future work includes comparison of isotopes and alkane ratios as tracers of methane sources, and calculation of total methane fluxes in the region using continuous measurements of methane concentrations during aircraft flights.

  15. Development of a high dynamic range spectroscopic system for observation of neutral hydrogen atom density distribution in Large Helical Device core plasma

    SciTech Connect

    Fujii, K. Atsumi, S.; Watanabe, S.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2014-02-15

    We report development of a high dynamic range spectroscopic system comprising a spectrometer with 30% throughput and a camera with a low-noise fast-readout complementary metal-oxide semiconductor sensor. The system achieves a 10{sup 6} dynamic range (∼20 bit resolution) and an instrumental function approximated by a Voigt profile with Gauss and Lorentz widths of 31 and 0.31 pm, respectively, for 656 nm light. The application of the system for line profile observations of the Balmeremissions from high temperature plasmas generated in the Large Helical Device is also presented. In the observed line profiles, emissions are detected in far wings more than 1.0 nm away from the line center, equivalent to neutral hydrogen atom kinetic energies above 1 keV. We evaluate atom density distributions in the core plasma by analyzing the line profiles.

  16. Photoelectron emission yield experiments on evolution of sub-gap states in amorphous In-Ga-Zn-O thin films with post deposition hydrogen treatment

    SciTech Connect

    Hayashi, Kazushi Hino, Aya; Tao, Hiroaki; Ochi, Mototaka; Goto, Hiroshi; Kugimiya, Toshihiro

    2015-09-14

    Total photoyield emission spectroscopy (TPYS) was applied to study the evolution of sub-gap states in hydrogen-treated amorphous In-Ga-Zn-O (a-IGZO) thin films. The a-IGZO thin films were subjected to hydrogen radicals and subsequently annealed in ultra-high vacuum (UHV) conditions. A clear onset of the electron emission was observed at around 4.3 eV from the hydrogen-treated a-IGZO thin films. After successive UHV annealing at 300 °C, the onset in the TPYS spectra was shifted to 4.15 eV, and the photoelectron emission from the sub-gap states was decreased as the annealing temperature was increased. In conjunction with the results of thermal desorption spectrometer, it was deduced that the hydrogen atoms incorporated in the a-IGZO thin films induced metastable sub-gap states at around 4.3 eV from vacuum level just after the hydrogenation. It was also suggested that the defect configuration was changed due to the higher temperature UHV annealing, and that the hydrogen atoms desorbed with the involvement of Zn atoms. These experiments produced direct evidence to show the formation of sub-gap states as a result of hydrogen incorporation into the a-IGZO thin films.

  17. Emissions of nitrogen oxides from an experimental hydrogen-fueled gas turbine combustor

    NASA Technical Reports Server (NTRS)

    Norgren, C. T.; Ingebo, R. D.

    1974-01-01

    The effect of operating variables of a hydrogen fueled combustor on exhaust concentrations of total oxides of nitrogen was determined at inlet-air temperature levels up to 810 K, pressure of 414,000N/sa m, and reference velocity of 21.3 m/sec. The combustor, which was originally designed for hydrocarbon fuel produced a NO(x) concentration of 380 ppm with hydrogen at 810 K inlet-air temperature. A reduction in NO(x) of about 30 % was obtained by modification to a lean or rich primary zone. The lowest NO(x) levels obtained with hydrogen were equivalent to those of the reference combustor burning hydrocarbon fuels.

  18. Atmospheric Physics and Earth Observations: Observations of Lyman-agr Emissions of Hydrogen and Deuterium.

    PubMed

    Bertaux, J L; Goutail, F; Kockarts, G

    1984-07-13

    A spectrophotometer was flown on Spacelab 1 to study various mechanisms of Lyman-alpha emission in the upper atmosphere. The use of absorption cells filled with H(2) and D(2) gases allowed us to discriminate a number of weak Lyman-alpha emissions heretofore masked by the strong H geocoronal emission due to resonance scattering of solar photons. Preliminary results are presented on three topics: the first optical detection of the deuterium Lyman-alpha emission at 110 kilometers, with an intensity of 330 rayleighs indicating an eddy diffusion coefficient of 1.3 x 10(6) square centimeters per second; auroral proton precipitations seen on both the night and the day side; and an emission located above 250 kilometers of altitude, interpreted as the result of charge exchange of magnetospheric protons with geocoronal atoms. PMID:17837930

  19. Highest Redshift Image of Neutral Hydrogen in Emission: A CHILES Detection of a Starbursting Galaxy at z = 0.376

    NASA Astrophysics Data System (ADS)

    Fernández, Ximena; Gim, Hansung B.; van Gorkom, J. H.; Yun, Min S.; Momjian, Emmanuel; Popping, Attila; Chomiuk, Laura; Hess, Kelley M.; Hunt, Lucas; Kreckel, Kathryn; Lucero, Danielle; Maddox, Natasha; Oosterloo, Tom; Pisano, D. J.; Verheijen, M. A. W.; Hales, Christopher A.; Chung, Aeree; Dodson, Richard; Golap, Kumar; Gross, Julia; Henning, Patricia; Hibbard, John; Jaffé, Yara L.; Donovan Meyer, Jennifer; Meyer, Martin; Sanchez-Barrantes, Monica; Schiminovich, David; Wicenec, Andreas; Wilcots, Eric; Bershady, Matthew; Scoville, Nick; Strader, Jay; Tremou, Evangelia; Salinas, Ricardo; Chávez, Ricardo

    2016-06-01

    Our current understanding of galaxy evolution still has many uncertainties associated with the details of the accretion, processing, and removal of gas across cosmic time. The next generation of radio telescopes will image the neutral hydrogen (H i) in galaxies over large volumes at high redshifts, which will provide key insights into these processes. We are conducting the COSMOS H i Large Extragalactic Survey (CHILES) with the Karl G. Jansky Very Large Array, which is the first survey to simultaneously observe H i from z = 0 to z ∼ 0.5. Here, we report the highest redshift H i 21 cm detection in emission to date of the luminous infrared galaxy COSMOS J100054.83+023126.2 at z = 0.376 with the first 178 hr of CHILES data. The total H i mass is (2.9 ± 1.0) × 1010 M ⊙ and the spatial distribution is asymmetric and extends beyond the galaxy. While optically the galaxy looks undisturbed, the H i distribution suggests an interaction with a candidate companion. In addition, we present follow-up Large Millimeter Telescope CO observations that show it is rich in molecular hydrogen, with a range of possible masses of (1.8–9.9) × 1010 M ⊙. This is the first study of the H i and CO in emission for a single galaxy beyond z ∼ 0.2.

  20. Highest Redshift Image of Neutral Hydrogen in Emission: A CHILES Detection of a Starbursting Galaxy at z = 0.376

    NASA Astrophysics Data System (ADS)

    Fernández, Ximena; Gim, Hansung B.; van Gorkom, J. H.; Yun, Min S.; Momjian, Emmanuel; Popping, Attila; Chomiuk, Laura; Hess, Kelley M.; Hunt, Lucas; Kreckel, Kathryn; Lucero, Danielle; Maddox, Natasha; Oosterloo, Tom; Pisano, D. J.; Verheijen, M. A. W.; Hales, Christopher A.; Chung, Aeree; Dodson, Richard; Golap, Kumar; Gross, Julia; Henning, Patricia; Hibbard, John; Jaffé, Yara L.; Donovan Meyer, Jennifer; Meyer, Martin; Sanchez-Barrantes, Monica; Schiminovich, David; Wicenec, Andreas; Wilcots, Eric; Bershady, Matthew; Scoville, Nick; Strader, Jay; Tremou, Evangelia; Salinas, Ricardo; Chávez, Ricardo

    2016-06-01

    Our current understanding of galaxy evolution still has many uncertainties associated with the details of the accretion, processing, and removal of gas across cosmic time. The next generation of radio telescopes will image the neutral hydrogen (H i) in galaxies over large volumes at high redshifts, which will provide key insights into these processes. We are conducting the COSMOS H i Large Extragalactic Survey (CHILES) with the Karl G. Jansky Very Large Array, which is the first survey to simultaneously observe H i from z = 0 to z ˜ 0.5. Here, we report the highest redshift H i 21 cm detection in emission to date of the luminous infrared galaxy COSMOS J100054.83+023126.2 at z = 0.376 with the first 178 hr of CHILES data. The total H i mass is (2.9 ± 1.0) × 1010 M ⊙ and the spatial distribution is asymmetric and extends beyond the galaxy. While optically the galaxy looks undisturbed, the H i distribution suggests an interaction with a candidate companion. In addition, we present follow-up Large Millimeter Telescope CO observations that show it is rich in molecular hydrogen, with a range of possible masses of (1.8–9.9) × 1010 M ⊙. This is the first study of the H i and CO in emission for a single galaxy beyond z ˜ 0.2.

  1. First hydrogen operation of NIO1: Characterization of the source plasma by means of an optical emission spectroscopy diagnostic.

    PubMed

    Barbisan, M; Baltador, C; Zaniol, B; Cavenago, M; Fantz, U; Pasqualotto, R; Serianni, G; Vialetto, L; Wünderlich, D

    2016-02-01

    NIO1 (Negative Ion Optimization 1) is a compact and flexible radio frequency H(-) ion source, developed by Consorzio RFX and INFN-LNL. The aim of the experimentation on NIO1 is the optimization of both the production of negative ions and their extraction and beam optics. In the initial phase of its commissioning, NIO1 was operated with nitrogen, but now the source is regularly operated also with hydrogen. To evaluate the source performances, an optical emission spectroscopy diagnostic was installed. The system includes a low resolution spectrometer in the spectral range of 300-850 nm and a high resolution (50 pm) one, to study, respectively, the atomic and the molecular emissions in the visible range. The spectroscopic data have been interpreted also by means of a collisional-radiative model developed at IPP Garching. Besides the diagnostic hardware and the data analysis methods, the paper presents the first plasma measurements across a transition to the full H mode, in a hydrogen discharge. The characteristic signatures of this transition in the plasma parameters are described, in particular, the sudden increase of the light emitted from the plasma above a certain power threshold. PMID:26932047

  2. Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows.

    PubMed

    Olijhoek, D W; Hellwing, A L F; Brask, M; Weisbjerg, M R; Højberg, O; Larsen, M K; Dijkstra, J; Erlandsen, E J; Lund, P

    2016-08-01

    Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. In a 4×4 Latin square design 4 lactating Danish Holstein dairy cows fitted with rumen, duodenal, and ileal cannulas were assigned to 4 calcium ammonium nitrate addition levels: control, low, medium, and high [0, 5.3, 13.6, and 21.1g of nitrate/kg of dry matter (DM), respectively]. Diets were made isonitrogenous by replacing urea. Cows were fed ad libitum and, after a 6-d period of gradual introduction of nitrate, adapted to the corn-silage-based total mixed ration (forage:concentrate ratio 50:50 on DM basis) for 16d before sampling. Digesta content from duodenum, ileum, and feces, and rumen liquid were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Methane production [L/kg of dry matter intake (DMI)] linearly decreased with increasing nitrate concentrations compared with the control, corresponding to a reduction of 6, 13, and 23% for the low, medium, and high diets, respectively. Methane production was lowered with apparent efficiencies (measured methane reduction relative to potential methane reduction) of 82.3, 71.9, and 79.4% for the low, medium, and high diets, respectively. Addition of nitrate increased hydrogen emissions (L/kg of DMI) quadratically by a factor of 2.5, 3.4, and 3.0 (as L/kg of DMI) for the low, medium, and high diets, respectively, compared with the control. Blood methemoglobin levels and nitrate concentrations in milk and urine increased with increasing nitrate intake, but did not constitute a threat for animal health and human food safety. Microbial crude protein synthesis and efficiency were unaffected. Total volatile fatty acid

  3. Catalytic process for control of NO.sub.x emissions using hydrogen

    DOEpatents

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2010-05-18

    A selective catalytic reduction process with a palladium catalyst for reducing NOx in a gas, using hydrogen as a reducing agent. A zirconium sulfate (ZrO.sub.2)SO.sub.4 catalyst support material with about 0.01-2.0 wt. % Pd is applied to a catalytic bed positioned in a flow of exhaust gas at about 70-200.degree. C. The support material may be (ZrO.sub.2--SiO.sub.2)SO.sub.4. H.sub.2O and hydrogen may be injected into the exhaust gas upstream of the catalyst to a concentration of about 15-23 vol. % H.sub.2O and a molar ratio for H.sub.2/NO.sub.x in the range of 10-100. A hydrogen-containing fuel may be synthesized in an Integrated Gasification Combined Cycle power plant for combustion in a gas turbine to produce the exhaust gas flow. A portion of the fuel may be diverted for the hydrogen injection.

  4. What sort of standard candle is Orion for studying molecular hydrogen line emission in galaxies

    NASA Technical Reports Server (NTRS)

    Burton, Michael; Puxley, Phil J.

    1990-01-01

    The total shocked and fluorescent molecular hydrogen 1-0 S(1) line luminosities from Orion have been measured to be about 2.5 solar luminosity and about 2.0 solar luminosity, respectively. The implications for using Orion to study the interstellar medium in galaxies is discussed.

  5. AN INTEGRATED ASSESSMENT OF THE IMPACTS OF HYDROGEN ECONOMY ON TRANSPORTATION, ENERGY USE, AND AIR EMISSIONS

    EPA Science Inventory

    This paper presents an analysis of the potential energy, economic and environmental implications of hydrogen fuel cell vehicle (H2-FCV) penetration into the U.S. light duty vehicle fleet. The approach, which uses the U.S. EPA MARKet ALlocation technology database and model, allow...

  6. Testing convection theories using Balmer line profiles of A, F, and G stars

    NASA Astrophysics Data System (ADS)

    Gardiner, R. B.; Kupka, F.; Smalley, B.

    1999-07-01

    We consider the effects of convection on the Balmer line profiles ({H_α} and {H_β}) of A, F, and G stars. The standard mixing-length theory (MLT) atlas9 models of Kurucz (1993), with and without overshooting, are compared to atlas9 models based on the turbulent convection theory proposed by Canuto & Mazzitelli (1991, 1992) and implemented by Kupka (1996), and the improved version of this model proposed by Canuto et al. (1996) also implemented by Kupka. The Balmer line profiles are a useful tool in investigating convection because they are very sensitive to the parameters of convection used in the stellar atmosphere codes. The {H_α} and {H_β} lines are formed at different depths in the atmosphere. The {H_α} line is formed just above the convection zone. The {H_β} line, however, is partially formed inside the convection zone. We have calculated the {T_eff} of observed stars by fitting Balmer line profiles to synthetic spectra and compared this to: (i) the {T_eff} of the fundamental stars; (ii) the {T_eff} of stars determined by the Infra-Red Flux Method and (iii) the {T_eff} determined by Geneva photometry for the stars in the Hyades cluster. We find that the results from the {H_α} and {H_β} lines are different, as expected, due to the differing levels of formation. The tests are inconclusive between three of the four models; MLT with no overshooting, CM and CGM models, which all give results in reasonable agreement with fundamental values. The results indicate that for the MLT theory with no overshooting it is necessary to set the mixing length parameter alpha equal to 0.5 for stars with {T_eff <= 6000} K or {T_eff >= 7000} K. However for stars with {6000} K{<= T_eff <= 7000} K the required value for the parameter is {alpha >= 1.25}. Models with overshooting are found to be clearly discrepant, consistent with the results with uvby photometry by Smalley & Kupka (1997). Based on observations made at the Observatorio del Roque de los Muchachos using the

  7. Emission of hydrogen sulfide by leaf tissue in response to L-cysteine

    SciTech Connect

    Sekiya, J.; Schmidt, A.; Wilson, L.G.; Filner, P.

    1982-08-01

    Leaf discs and detached leaves exposed to L-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H/sub 2/S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. The emission of leaf discs reached the maximal rate, more than 40 picomoles per minute per square centimeter, 2 to 4 hours after starting exposure to L-cysteine; then it decreased. In the case of detached leaves, the maximum occurred 5 to 10 h after starting exposure. The average emission rate of H/sub 2/S during the first 4 hours from leaf discs of cucurbits in response to 10 millimolar L-cysteine, was usually more than 40 picomoles per minute per square centimeter, i.e. 0.24 micromoles per hour per square decimeter. Leaf discs exposed to 1 millimolar L-cysteine emitted only 2% as much as did the discs exposed to 10 millimolar L-cysteine. The emission from leaf discs and from detached leaves lasted for at least 5 and 15 hours, respectively. However, several hours after the maximal emission, injury of the leaves, manifested as chlorosis, was evident. H/sub 2/S emission was a specific consequence of exposure to L-cysteine; neither D-cysteine nor L-cysteine elicited H/sub 2/S emission. Aminooxyacetic acid, an inhibitor of pyridoxal phosphate dependent enzymes, inhibited the emission. In a cell free system from cucumber leaves, H/sub 2/S formation and its release occurred in response to L-cysteine. Feeding experiments with (/sup 35/S)t-cysteine showed that most of the sulfur in H/sub 2/S was derived from sulfur in the L-cysteine supplied.

  8. Hydrogen and methane emissions from beef cattle and their rumen microbial community vary with diet, time after feeding and genotype.

    PubMed

    Rooke, John A; Wallace, R John; Duthie, Carol-Anne; McKain, Nest; de Souza, Shirley Motta; Hyslop, Jimmy J; Ross, David W; Waterhouse, Tony; Roehe, Rainer

    2014-08-14

    The aims of the present study were to quantify hydrogen (H2) and methane (CH4) emissions from beef cattle under different dietary conditions and to assess how cattle genotype and rumen microbial community affected these emissions. A total of thirty-six Aberdeen Angus-sired (AAx) and thirty-six Limousin-sired (LIMx) steers were fed two diets with forage:concentrate ratios (DM basis) of either 8:92 (concentrate) or 52:48 (mixed). Each diet was fed to eighteen animals of each genotype. Methane (CH4) and H2 emissions were measured individually in indirect respiration chambers. H2 emissions (mmol/min) varied greatly throughout the day, being highest after feed consumption, and averaged about 0·10 mol H2/mol CH4. Higher H2 emissions (mol/kg DM intake) were recorded in steers fed the mixed diet. Higher CH4 emissions (mol/d and mol/kg DM intake) were recorded in steers fed the mixed diet (P< 0·001); the AAx steers produced more CH4 on a daily basis (mol/d, P< 0·05) but not on a DM intake basis (mol/kg DM intake). Archaea (P= 0·002) and protozoa (P< 0·001) were found to be more abundant and total bacteria (P< 0·001) less abundant (P< 0·001) on feeding the mixed diet. The relative abundance of Clostridium cluster IV was found to be greater (P< 0·001) and that of cluster XIVa (P= 0·025) lower on feeding the mixed diet. The relative abundance of Bacteroides plus Prevotella was greater (P= 0·018) and that of Clostridium cluster IV lower (P= 0·031) in the LIMx steers. There were no significant relationships between H2 emissions and microbial abundance. In conclusion, the rate of H2 production immediately after feeding may lead to transient overloading of methanogenic archaea capacity to use H2, resulting in peaks in H2 emissions from beef cattle. PMID:24780126

  9. Light emission induced by an XUV laser pulse interacting resonantly with atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Li, Qingyi; Zhang, Zhiyuan; Zhang, Yunfeng; Li, Suyu; Guo, Fuming; Yang, Yujun

    2016-01-01

    The resonant interaction between XUV ultra-short laser pulses and atomic hydrogen is systematically studied by numerically solving the time-dependent Schrödinger equation in this paper. Triple-peak structures are found to appear in the harmonics emitted provided that the incident laser is resonant with the 1 s-2p transition of the hydrogen atom. Moreover, the energy difference between neighboring peaks is the same and turns out to be proportional to the peak field strength E 0. Based on the theory of strong field approximation, and taking the interactions of the 1 s-2p bound energy levels into consideration, theoretical interpretations of the phenomena mentioned are successfully presented. This work provides a possible approach for generating XUV radiation with a tunable frequency via the interaction between atoms and XUV laser pulses.

  10. THE 217.5 nm BAND, INFRARED ABSORPTION, AND INFRARED EMISSION FEATURES IN HYDROGENATED AMORPHOUS CARBON NANOPARTICLES

    SciTech Connect

    Duley, W. W.; Hu, Anming E-mail: a2hu@uwaterloo.ca

    2012-12-20

    We report on the preparation of hydrogenated amorphous carbon nanoparticles whose spectral characteristics include an absorption band at 217.5 nm with the profile and characteristics of the interstellar 217.5 nm feature. Vibrational spectra of these particles also contain the features commonly observed in absorption and emission from dust in the diffuse interstellar medium. These materials are produced under ''slow'' deposition conditions by minimizing the flux of incident carbon atoms and by reducing surface mobility. The initial chemistry leads to the formation of carbon chains, together with a limited range of small aromatic ring molecules, and eventually results in carbon nanoparticles having an sp {sup 2}/sp {sup 3} ratio Almost-Equal-To 0.4. Spectroscopic analysis of particle composition indicates that naphthalene and naphthalene derivatives are important constituents of this material. We suggest that carbon nanoparticles with similar composition are responsible for the appearance of the interstellar 217.5 nm band and outline how these particles can form in situ under diffuse cloud conditions by deposition of carbon on the surface of silicate grains. Spectral data from carbon nanoparticles formed under these conditions accurately reproduce IR emission spectra from a number of Galactic sources. We provide the first detailed fits to observational spectra of Type A and B emission sources based entirely on measured spectra of a carbonaceous material that can be produced in the laboratory.

  11. On Formation Of HXR, Hydrogen, White Light Emission and Sunquakes in Hydrodynamic Flaring Atmospheres Heated by Particle Beams

    NASA Astrophysics Data System (ADS)

    Dobranskis, R.; Zharkova, V. V.; Zharkov, S.; Druett, M.

    2014-12-01

    We report analysis of kinetic simulations for precipitation of various particle beams (electrons, protons, mixed beam) and hydrodynamic simulations of flaring atmosphere heating by these beams using the approach described by Zharkova and Zharkov (2007). The results show temperature, density and macro-velocity variations as functions of both column and linear depths that for some beam parameters reveals a strong suppression of the upper atmosphere in a form of shocks towards the photosphere and beneath into the solar interior at some distances of 500-3000 km. The shocks deposited at different depths below the photosphere are found to produce varying seismic responses as per model by Zharkov (2013) while the atmospheres above the photosphere reveal various degrees of evaporation of the pressed ambient plasma into the corona depending on beam parameters. After a beam switch off the flaring atmospheres are shown to relax within short timescales to their original status. For physical models corresponding to hydrodynamic responses above we also simulate hydrogen emission produced by these atmospheres using full non-LTE approach and considering collisional excitation and ionisation by electron beams. We compare temporal and spatial distributions of HXR and optical emission in some flares with those produced by the complex simulations above, in attempt to resolve the puzzle of co-spatial formation of HXR and WL emission reported by Martinez-Oliveros et al. (2012).

  12. The Infrared Spectrum of Protonated Ovalene in Solid Para-Hydrogen and its Possible Contribution to Interstellar Unidentified Infrared Emission

    NASA Astrophysics Data System (ADS)

    Tsuge, Masashi; Bahou, Mohammed; Wu, Yu-Jong; Allamandola, Louis; Lee, Yuan-Pern

    2016-07-01

    The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H+PAHs) were proposed as possible carriers, but no spectrum of an H+PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C32H15 +) measured in a para-hydrogen (p-H2) matrix at 3.2 K, generated by bombarding a mixture of ovalene and p-H2 with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d,2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.

  13. Proton emission from thin hydrogenated targets irradiated by laser pulses at 10{sup 16} W/cm{sup 2}

    SciTech Connect

    Torrisi, L.; Giuffrida, L.; Cirrone, P.; Cutroneo, M.; Picciotto, A.; Krasa, J.; Margarone, D.; Velyhan, A.; Laska, L.; Ullschmied, J.; Wolowski, J.; Badziak, J.; Rosinski, M.

    2012-02-15

    The iodine laser at PALS Laboratory in Prague, operating at 1315 nm fundamental harmonics and at 300 ps FWHM pulse length, is employed to irradiate thin hydrogenated targets placed in vacuum at intensities on the order of 10{sup 16} W/cm{sup 2}. The laser-generated plasma is investigated in terms of proton and ion emission in the forward and backward directions. The time-of-flight technique, using ion collectors and semiconductor detectors, is used to measure the ion currents and the corresponding velocities and energies. Thomson parabola spectrometer is employed to separate the contribution of the ion emission from single laser shots. A particular attention is given to the proton production in terms of the maximum energy, emission yield, and angular distribution as a function of the laser energy, focal position, target thickness, and composition. Metallic and polymeric targets allow to generate protons with large energy range and different yield, depending on the laser, target composition, and target geometry properties.

  14. The effect of surface oxide layer on the rate of hydrogen emission from aluminum and its alloys in a high vacuum

    NASA Technical Reports Server (NTRS)

    Makarova, V. I.; Zyabrev, A. A.

    1979-01-01

    The influence of surface oxide layers on the kinetics of hydrogen emission at the high vacuum of 10 to the minus 8th power torr was investigated at temperatures from 20 to 450 C using samples of pure AB00 aluminum and the cast alloy AMg. Cast and deformed samples of AMts alloy were used to study the effect of oxide film thickness on the rate of hydrogen emission. Thermodynamic calculations of the reactions of the generation and dissociation of aluminum oxide show that degasification at elevated temperatures (up to 600 C) and high vacuum will not reduce the thickness of artificially-generated surface oxide layers on aluminum and its alloys.

  15. Stark broadening measurements in plasmas produced by laser ablation of hydrogen containing compounds

    NASA Astrophysics Data System (ADS)

    Burger, Miloš; Hermann, Jörg

    2016-08-01

    We present a method for the measurement of Stark broadening parameters of atomic and ionic spectral lines based on laser ablation of hydrogen containing compounds. Therefore, plume emission spectra, recorded with an echelle spectrometer coupled to a gated detector, were compared to the spectral radiance of a plasma in local thermal equilibrium. Producing material ablation with ultraviolet nanosecond laser pulses in argon at near atmospheric pressure, the recordings take advantage of the spatially uniform distributions of electron density and temperature within the ablated vapor. By changing the delay between laser pulse and detector gate, the electron density could be varied by more than two orders of magnitude while the temperature was altered in the range from 6,000 to 14,000 K. The Stark broadening parameters of transitions were derived from their simultaneous observation with the hydrogen Balmer alpha line. In addition, assuming a linear increase of Stark widths and shifts with electron density for non-hydrogenic lines, our measurements indicate a change of the Stark broadening-dependence of Hα over the considered electron density range. The presented results obtained for hydrated calcium sulfate (CaSO4ṡ2H2O) can be extended to any kind of hydrogen containing compounds.

  16. H I free-bound emission of planetary nebulae with large abundance discrepancies: Two-component models versus κ-distributed electrons

    SciTech Connect

    Zhang, Yong; Liu, Xiao-Wei; Zhang, Bing

    2014-01-01

    The 'abundance discrepancy' problem in the study of planetary nebulae (PNe), viz., the problem concerning systematically higher heavy-element abundances derived from optical recombination lines relative to those from collisionally excited lines, has been under discussion for decades, but no consensus on its solution has yet been reached. In this paper, we investigate the hydrogen free-bound emission near the Balmer jump region of four PNe that are among those with the largest abundance discrepancies, aiming to examine two recently proposed solutions to this problem: two-component models and κ electron energy distributions. We find that the Balmer jump intensities and the spectrum slopes cannot be simultaneously matched by the theoretical calculations based upon single Maxwell-Boltzmann electron-energy distributions, whereas the fitting can be equally improved by introducing κ electron energy distributions or an additional Maxwell-Boltzmann component. We show that although H I free-bound emission alone cannot distinguish between the two scenarios, it can provide important constraints on the electron energy distributions, especially for cold and low-κ plasmas.

  17. Study on The Difference Between Proper-Motion of Halpha line emission and Non-Thermal X-Ray emission In Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Shimoda, Jiro; Ohira, Yutaka; Yamazaki, Ryo; Inoue, Tsuyoshi; Soeda, Masanobu

    Balmer line emission (Halpha) by neutral hydrogen and X-ray synchrotron emission by accelerated electrons are observed from some supernova remnants (SNRs), which are thought as accelerators of galactic cosmic rays (CRs). From these observations, the cosmic ray acceleration efficiency is estimated. According to the theory of diffusive shock acceleration (DSA), electrons are accelerated around the shock front, and emit the synchrotron radiation. Measurement of proper motion of the synchrotron X-rays gives the shock velocity. At the same time, we can estimate the post shock temperature from the line width of Halpha emission, because neutral hydrogen collide with downstream hot protons and exchange their charge, so that the hot neutral component arises. In the specific case of a SNR RCW86, measured expansion speed of Halpha filament is about 1200km/s (Helder et al. 2013), while 6000km/s in X-rays (Helder et al. 2009). It is expected that the emission regions of the Halpha and the synchrotron X-rays are different. However, they are overlaid in the same line of sight. In this study, using three dimensional magnetohydrodynamics (MHD) simulations, we consider propagation of supernova blast wave shock in realistic inhomogeneous interstellar medium. Interaction between the upstream density inhomogeneity and the shock wave causes rippled shock structure and fluctuation of local shock velocity.We show that our synthetic observations of the MHD simulation data are consistent with actual observation results for RCW86.

  18. Variations of the high-level Balmer line spectrum of the helium-strong star σ Orionis E

    NASA Astrophysics Data System (ADS)

    Smith, M. A.; Bohlender, D. A.

    2007-12-01

    Using the high-level Balmer lines and continuum, we trace the density structure of two magnetospheric disk segments of the prototypical Bp star σ Orionis E (B2p) as these segments occult portions of the star during the rotational cycle. High-resolution spectra of the Balmer lines ≥H9 and Balmer edge were obtained on seven nights in January-February 2007 at an average sampling of 0.01 cycles. We measured equivalent width variations due to the star occultations by two disk segments 0.4 cycles apart and constructed differential spectra of the migrations of the corresponding absorptions across the Balmer line profiles. We first estimated the rotational and magnetic obliquity angles. We then simulated the observed Balmer jump variation using the model atmosphere codes synspec/circus and evaluated the disk geometry and gas thermodynamics. We find that the two occultations are caused by two disk segments. The first of these transits quickly, indicating that the segment resides in a range of distances, perhaps 2.5-6 R*, from the star. The second consists of a more slowly moving segment situated closer to the surface and causing two semi-resolved absorbing maxima. During its transit this segment brushes across the star's “lower” limb. Judging from the line visibility up to H23-H24 during the occultations, both disk segments have mean densities near 1012 cm-3 and are opaque in the lines and continuum. They have semiheights less than 1/2 R*, and their temperatures are near 10 500 K and 12 000 K, respectively. In all, the disks of Bp stars have a much more complicated geometry than has been anticipated, as evidenced by their (sometimes) non-coplanarity, de-centerness, and from star to star, differences in disk height. Based on observations obtained at the the Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada.

  19. Emission of Hydrogen Sulfide by Leaf Tissue in Response to l-Cysteine 1

    PubMed Central

    Sekiya, Jiro; Schmidt, Ahlert; Wilson, Lloyd G.; Filner, Philip

    1982-01-01

    Leaf discs and detached leaves exposed to l-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H2S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. The emission of leaf discs reached the maximal rate, more than 40 picomoles per minute per square centimeter, 2 to 4 hours after starting exposure to l-cysteine; then it decreased. In the case of detached leaves, the maximum occurred 5 to 10 h after starting exposure. The average emission rate of H2S during the first 4 hours from leaf discs of cucurbits in response to 10 millimolar l-cysteine, was usually more than 40 picomoles per minute per square centimeter, i.e. 0.24 micromoles per hour per square decimeter. Leaf discs exposed to 1 millimolar l-cysteine emitted only 2% as much as did the discs exposed to 10 millimolar l-cysteine. The emission from leaf discs and from detached leaves lasted for at least 5 and 15 hours, respectively. However, several hours after the maximal emission, injury of the leaves, manifested as chlorosis, was evident. H2S emission was a specific consequence of exposure to l-cysteine; neither d-cysteine nor l-cystine elicited H2S emission. Aminooxyacetic acid, an inhibitor of pyridoxal phosphate dependent enzymes, inhibited the emission. In a cell free system from cucumber leaves, H2S formation and its release occurred in response to l-cysteine. Feeding experiments with [35S]l-cysteine showed that most of the sulfur in H2S was derived from sulfur in the l-cysteine supplied and that the H2S emitted for 9 hours accounted for 7 to 10% of l-cysteine taken up. 35S-labeled SO32− and SO42− were found in the tissue extract in addition to internal soluble S2−. These findings

  20. Modeling hydrogen sulfide emissions across the gas-liquid interface of an anaerobic swine waste treatment storage system

    NASA Astrophysics Data System (ADS)

    Blunden, Jessica; Aneja, Viney P.; Overton, John H.

    Hydrogen sulfide (H 2S) is a colorless gas emitted during decomposition of hog manure that produces an offensive "rotten egg" smell and is considered a toxic manure gas. In the southeastern United States, anaerobic waste treatment lagoons are widely used to store and treat hog excreta at commercial hog farms. Hydrogen sulfide is produced as manure decomposes anaerobically, resulting from the mineralization of organic sulfur compounds as well as the reduction of oxidized inorganic sulfur compounds by sulfur-reducing bacteria. The process of H 2S emissions from anaerobic waste treatment lagoons are investigated utilizing a two-film model with three different modeling approaches: Coupled Mass Transfer with Chemical Reactions Model with the assumption (1) pH remains constant in the liquid film (MTCR Model I) and (2) pH may change throughout the liquid film due to diffusion processes that occur within the film (MTCR Model II); and (3) a Mass Transfer Model which neglects chemical reactions (MTNCR Model) in the gas and liquid films. Results of model predictions are consistent with previous works, which show that flux is largely dependent on the physicochemical lagoon properties including sulfide concentration, pH, and lagoon temperature. Air temperature and low wind velocities (e.g., <3.25 m s -1) have negligible impact on flux. Results also indicate that flux values decrease with increased film thickness. The flux was primarily influenced by variations in the liquid film thickness, signifying that the H 2S flux is driven by liquid-phase parameters. Model results were compared with H 2S flux measurements made at a swine waste treatment storage lagoon in North Carolina using a dynamic emission flux chamber system in order to evaluate model accuracy in calculating lagoon H 2S emissions. The MTCR Model II predicted the highest increase in emission rates as aqueous sulfide concentration was increased. The MTNCR Model showed the highest dependence on pH. All three models

  1. Cosmology on Ultralarge Scales with Intensity Mapping of the Neutral Hydrogen 21 cm Emission: Limits on Primordial Non-Gaussianity

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  2. Atomic emission lines in the near ultraviolet; hydrogen through krypton, section 1

    NASA Technical Reports Server (NTRS)

    Kelly, R. L.

    1979-01-01

    A compilation of spectra from the first 36 elements was prepared from published literature available through October 1977. In most cases, only those lines which were actually observed in emission or absorption are listed. The wavelengths included range from 2000 Angstroms to 3200 Angstroms with some additional lines up to 3500 Angstroms. Only lines of stripped atoms are reported; no molecular bands are included.

  3. Atomic emission lines in the near ultraviolet; hydrogen through krypton, section 2

    NASA Technical Reports Server (NTRS)

    Kelly, R. L.

    1979-01-01

    A compilation of spectra from the first 36 elements was prepared from published literature available through October 1977. In most cases, only those lines which were actually observed in emission or absorption are listed. The wavelengths included range from 2000 Angstroms to 3200 Angstroms with some additional lines up to 3500 Angstroms. Only lines of stripped atoms are reported; no molecular bands are included.

  4. Effects of borax treatment on hydrogen sulfide emissions and sulfate reducing bacteria in stored swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malodorous compounds and emissions produced from stored swine manure can pose both environmental and health issues. These nuisance odors largely result from compounds such as sulfides, volatile fatty acids, and phenols, which are produced as a result of anaerobic digestion of materials present in t...

  5. Tuned NV emission by in-plane Al-Schottky junctions on hydrogen terminated diamond

    PubMed Central

    Schreyvogel, Christoph; Wolfer, Marco; Kato, Hiromitsu; Schreck, Matthias; Nebel, Christoph E.

    2014-01-01

    The negatively charged nitrogen-vacancy (NV) centre exhibits outstanding optical and spin properties and thus is very attractive for applications in quantum optics. Up to now an active control of the charge state of near-surface NV centres is difficult and the centres switch in an uncontrolled way between different charge states. In this work, we demonstrate an active control of the charge state of NV centres (implanted 7 nm below the surface) by using an in-plane Schottky diode geometry from aluminium on hydrogen terminated diamond in combination with confocal micro-photoluminescence measurements. The partial quenching of NV-photoluminescence caused by the hole accumulation layer of the hydrogen terminated surface can be recovered by applying reverse bias potentials on this diode, i.e. the NV0 charge state is depleted while the NV− charge state is populated. This charge state conversion is caused by the bias voltage affected modulation of the band bending in the depletion region which shifts the Fermi level across the NV charge transition levels. PMID:24407227

  6. Unmodified versus caustics-impregnated carbons for control of hydrogen sulfide emissions from sewage treatment plants

    SciTech Connect

    Bandosz, T.J.; Bagreev, A.; Adib, F.; Turk, A.

    2000-03-15

    Unmodified and caustic-impregnated carbons were compared as adsorbents for hydrogen sulfide in the North River Water Pollution Control Plant in New York City over a period of 2 years. The carbons were characterized using accelerated H{sub 2}S breakthrough capacity tests, sorption of nitrogen, potentiometric titration, and thermal analysis. The accelerated laboratory tests indicate that the initial capacity of caustic-impregnated carbons exceeds that of unmodified carbon, but the nature of real-life challenge streams, particularly their lower H{sub 2}S concentrations, nullifies this advantage. As the caustic content of the impregnated carbon is consumed, the situation reverses, and the unmodified carbon becomes more effective. When the concentration of H{sub 2}S is low, the developed surface area and pore volume along with the affinity to retain water create a favorable environment for dissociative adsorption of hydrogen sulfide and its oxidation to elemental sulfur, S{sup 4+}, and S{sup 6+}. In the case of the caustic carbon, the catalytic impact of the carbon surface is limited, and its good performance lasts only while active base is present. The results also show the significant differences in performance of unmodified carbons due to combined effects of their porosity and surface chemistry.

  7. Electron field emission from phase pure nanotube films grown in a methane/hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Küttel, Olivier M.; Groening, Oliver; Emmenegger, Christoph; Schlapbach, Louis

    1998-10-01

    Phase pure nanotube films were grown on silicon substrates by a microwave plasma under conditions which normally are used for the growth of chemical vapor deposited diamond films. However, instead of using any pretreatment leading to diamond nucleation we deposited metal clusters on the silicon substrate. The resulting films contain only nanotubes and also onion-like structures. However, no other carbon allotropes like graphite or amorphous clustered material could be found. The nanotubes adhere very well to the substrates and do not need any further purification step. Electron field emission was observed at fields above 1.5 V/μm and we observed an emission site density up to 104/cm2 at 3 V/μm. Alternatively, we have grown nanotube films by the hot filament technique, which allows to uniformly cover a two inch wafer.

  8. Tracing the Milky Way Nuclear Wind with 21cm Atomic Hydrogen Emission

    NASA Astrophysics Data System (ADS)

    Lockman, Felix J.; McClure-Griffiths, N. M.

    2016-08-01

    There is evidence in 21 cm H i emission for voids several kiloparsecs in size centered approximately on the Galactic center, both above and below the Galactic plane. These appear to map the boundaries of the Galactic nuclear wind. An analysis of H i at the tangent points, where the distance to the gas can be estimated with reasonable accuracy, shows a sharp transition at Galactic radii R ≲ 2.4 kpc from the extended neutral gas layer characteristic of much of the Galactic disk, to a thin Gaussian layer with FWHM ∼ 125 pc. An anti-correlation between H i and γ-ray emission at latitudes 10^\\circ ≤slant | b| ≤slant 20^\\circ suggests that the boundary of the extended H i layer marks the walls of the Fermi Bubbles. With H i, we are able to trace the edges of the voids from | z| \\gt 2 {{kpc}} down to z ≈ 0, where they have a radius ∼2 kpc. The extended Hi layer likely results from star formation in the disk, which is limited largely to R ≳ 3 kpc, so the wind may be expanding into an area of relatively little H i. Because the H i kinematics can discriminate between gas in the Galactic center and foreground material, 21 cm H i emission may be the best probe of the extent of the nuclear wind near the Galactic plane.

  9. Zero emission coal: a future source of clean electric power and hydrogen

    SciTech Connect

    Ziock, H. J.

    2001-01-01

    The pairing of two novel technologies may permit coal energy to satisfy a dramatically increasing world energy demand for the next few hundred years. This can be done while virtually eliminating not only airborne SO{sub x}, NO{sub x}, mercury and particulate emissions, but also the main greenhouse gas, carbon dioxide (CO{sub 2}). The Zero Emission Coal Alliance, a collaboration of approximately 20 international industrial and government entities is investigating these concepts with the objective of completing the first pilot plant within 5 years. Paradoxically, climate change was not the overriding consideration that drove the development of these inventions. The more important consideration was that, if world carbon use continues to accelerate at rates even close to those in the last century, carbon from fossil fuels will overwhelm the natural CO{sub 2} sinks. In this view, the 'Kyoto' objectives are almost meaningless and misdirect enormous resources - both human and financial. If a world population of 10 billion reaches a standard of living comaprable, on the average, to that of the US in 2000 (with similar carbon use), then world yearly CO{sub 2} emissions will be ten times their current level. Carbon (in the form of coal) is our most important energy resource. The Challenge is to find sustainable ways of using it.

  10. Tracing the Milky Way Nuclear Wind with 21cm Atomic Hydrogen Emission

    NASA Astrophysics Data System (ADS)

    Lockman, Felix J.; McClure-Griffiths, N. M.

    2016-08-01

    There is evidence in 21 cm H i emission for voids several kiloparsecs in size centered approximately on the Galactic center, both above and below the Galactic plane. These appear to map the boundaries of the Galactic nuclear wind. An analysis of H i at the tangent points, where the distance to the gas can be estimated with reasonable accuracy, shows a sharp transition at Galactic radii R ≲ 2.4 kpc from the extended neutral gas layer characteristic of much of the Galactic disk, to a thin Gaussian layer with FWHM ˜ 125 pc. An anti-correlation between H i and γ-ray emission at latitudes 10^\\circ ≤slant | b| ≤slant 20^\\circ suggests that the boundary of the extended H i layer marks the walls of the Fermi Bubbles. With H i, we are able to trace the edges of the voids from | z| \\gt 2 {{kpc}} down to z ≈ 0, where they have a radius ˜2 kpc. The extended Hi layer likely results from star formation in the disk, which is limited largely to R ≳ 3 kpc, so the wind may be expanding into an area of relatively little H i. Because the H i kinematics can discriminate between gas in the Galactic center and foreground material, 21 cm H i emission may be the best probe of the extent of the nuclear wind near the Galactic plane.

  11. Combination of borax and quebracho condensed tannins treatment to reduce hydrogen sulfide, ammonia and greenhouse gas emissions from stored swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock producers are acutely aware for the need to reduce gaseous emissions from stored livestock waste and have been trying to identify new technologies to address the chronic problem. Besides the malodor issue, toxic gases emitted from stored livestock manure, especially hydrogen sulfide (H2S)...

  12. Hydrogen Fuel Cell Vehicle Fuel Economy Testing at the U.S. EPA National Vehicle and Fuel Emissions Laboratory (SAE Paper 2004-01-2900)

    EPA Science Inventory

    The introduction of hydrogen fuel cell vehicles and their new technology has created the need for development of new fuel economy test procedures and safety procedures during testing. The United States Environmental Protection Agency-National Vehicle Fuels and Emissions Laborato...

  13. Best Management Practices to Prevent and Control Hydrogen Sulfide and Reduced Sulfur Compound Emissions at Landfills That Dispose of Gypsum Drywall

    EPA Science Inventory

    Hydrogen sulfide (H2S) gas can be emitted from both construction and demolition (C&D) debris and municipal solid waste (MSW) landfills. H2S emissions may be problematic at a landfill as they can cause odor, impact surrounding communities, cause wear or dama...

  14. The effects of calcium hydroxide on hydrogen chloride emission characteristics during a simulated densified refuse-derived fuel combustion process.

    PubMed

    Chiang, Kung-Yuh; Jih, Jer-Chyuan; Lin, Kae-Long

    2008-08-30

    This study investigated the effects of different calcium hydroxide (Ca(OH)(2)) addition methods on the potential for hydrogen chloride (HCl) formation in a simulated densified refuse-derived fuel (RDF-5) with single metal combustion system. These experiments were conducted at 850 degrees C with the Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. The results indicated that the potential for HCl formation was decreased significantly by Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. However, the Ca(OH)(2) injection method in the flue gas for HCl emission reduction was better than other method. According to the relationship between the HCl emission and amount of Ca(OH)(2) injected or spiked, it is interesting to find that when the Ca(OH)(2) injected or spiked ranged from 0% to 5%, the potential for HCl formation in the single metal combustion system decreases significantly with increasing Ca(OH)(2) injected or spiked ratio. A corresponding increase in the amount of CaCl(2) partitioned to the fly ash was observed. However, with the ratio of Ca(OH)(2) higher than 5%, the amount of HCl formation showed that no further significant variation occurred with increasing Ca(OH)(2) spiked ratio. PMID:18272287

  15. Plasma and Electrode Emissions from a 1 kW Hydrogen-Nitrogen Arcjet Thruster

    SciTech Connect

    Huang Heji; Pan Wenxia; Meng Xian; Wu Chengkang

    2010-05-21

    Arc root behavior affects the energy transfer and nozzle erosion in an arcjet thruster. To investigate the development of arc root attachment in 1 kW class N{sub 2} and H{sub 2}-N{sub 2} arcjet thrusters from the time of ignition to the stably working condition, a kinetic series of end-on view images of the nozzle obtained by a high-speed video camera was analyzed. The addition of hydrogen leads to higher arc voltage levels and the determining factor for the mode of arc root attachment was found to be the nozzle temperature. At lower nozzle temperatures, constricted type attachment with unstable motions of the arc root was observed, while a fully diffused and stable arc root was observed at elevated nozzle temperatures.

  16. Spontaneous light emission by atomic hydrogen: Fermi's golden rule without cheating

    NASA Astrophysics Data System (ADS)

    Debierre, V.; Durt, T.; Nicolet, A.; Zolla, F.

    2015-10-01

    Focusing on the 2 p- 1 s transition in atomic hydrogen, we investigate through first order perturbation theory the time evolution of the survival probability of an electron initially taken to be in the excited (2 p) state. We examine both the results yielded by the standard dipole approximation for the coupling between the atom and the electromagnetic field - for which we propose a cutoff-independent regularisation - and those yielded by the exact coupling function. In both cases, Fermi's golden rule is shown to be an excellent approximation for the system at hand: we found its maximal deviation from the exact behaviour of the system to be of order 10-8 /10-7. Our treatment also yields a rigorous prescription for the choice of the optimal cutoff frequency in the dipole approximation. With our cutoff, the predictions of the dipole approximation are almost indistinguishable at all times from the exact dynamics of the system.

  17. Plasma and Electrode Emissions from a 1 kW Hydrogen-Nitrogen Arcjet Thruster

    NASA Astrophysics Data System (ADS)

    Huang, Heji; Pan, Wenxia; Meng, Xian; Wu, Chengkang

    2010-05-01

    Arc root behavior affects the energy transfer and nozzle erosion in an arcjet thruster. To investigate the development of arc root attachment in 1 kW class N2 and H2-N2 arcjet thrusters from the time of ignition to the stably working condition, a kinetic series of end-on view images of the nozzle obtained by a high-speed video camera was analyzed. The addition of hydrogen leads to higher arc voltage levels and the determining factor for the mode of arc root attachment was found to be the nozzle temperature. At lower nozzle temperatures, constricted type attachment with unstable motions of the arc root was observed, while a fully diffused and stable arc root was observed at elevated nozzle temperatures.

  18. INTERACTING GALACTIC NEUTRAL HYDROGEN FILAMENTS AND ASSOCIATED HIGH-FREQUENCY CONTINUUM EMISSION

    SciTech Connect

    Verschuur, Gerrit L.

    2013-05-10

    Galactic H I emission profiles in an area where several large-scale filaments at velocities ranging from -46 km s{sup -1} to 0 km s{sup -1} overlap were decomposed into Gaussian components. Eighteen families of components defined by similarities of center velocity and line width were identified and related to small-scale structure in the high-frequency continuum emission observed by the Wilkinson Microwave Anisotropy Probe spacecraft, as evidenced in the Internal Linear Combination (ILC) map of Hinshaw et al. When the center velocities of the Gaussian families, which summarize the properties of all the H I along the lines of sight in a given area, are used to focus on H I channel maps the phenomenon of close associations between H I and ILC peaks reported in previous papers is dramatically highlighted. Of particular interest, each of two pairs of H I peaks straddles a continuum peak. The previously hypothesized model for producing the continuum radiation involving free-free emission from electrons is re-examined in light of the new data. By choosing reasonable values for the parameters required to evaluate the model, the distance for associated H I-ILC features is of order 30-100 pc. No associated H{alpha} radiation is expected because the electrons involved exist throughout the Milky Way. The mechanism for clumping and separation of neutrals and electrons needs to be explored. It is concluded that the small-scale ILC structure originates in the local interstellar medium and not at cosmological distances.

  19. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research.

    PubMed

    Lampert, M; Anda, G; Czopf, A; Erdei, G; Guszejnov, D; Kovácsik, Á; Pokol, G I; Réfy, D; Nam, Y U; Zoletnik, S

    2015-07-01

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera's measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties. PMID:26233377

  20. Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements.

    PubMed

    Chérigier-Kovacic, L; Ström, P; Lejeune, A; Doveil, F

    2015-06-01

    Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied. PMID:26133836

  1. Neutral hydrogen in elliptical galaxies with nuclear radio sources and optical emission lines

    NASA Technical Reports Server (NTRS)

    Dressel, L. L.; Bania, T. M.; Oconnell, R. W.

    1982-01-01

    An H I detection survey of eleven elliptical galaxies with powerful nuclear radio sources was conducted, using the 305 m antenna of Arecibo Observatory, to test the hypothesis that large H I mass is conductive to the formation of nuclear radio sources in elliptical galaxies. The H I was detected in emission in UGC 09114 and was possibly detected in absorption in UGC 06671. Observations of the remaining galaxies were not sensitive enough to support or refute the hypothesis. Data was combined from other H I surveys and spectroscopic surveys to search for correlations of H I mass with other galactic properties and environmental conditions. Strong correlations of (O II) lambda 3727 emission with H I content and with nuclear radio power were found. The latter two properties may simply indicate, respectively, whether a significant amount of gas is available to be ionized and whether energy is provided by nuclear activity for ionization. No dependence of H I content on optical luminosity or on degree of isolation from other galaxies was found.

  2. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Lampert, M.; Anda, G.; Réfy, D.; Zoletnik, S.; Czopf, A.; Erdei, G.; Guszejnov, D.; Kovácsik, Á.; Pokol, G. I.; Nam, Y. U.

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  3. Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements

    SciTech Connect

    Chérigier-Kovacic, L. Doveil, F.; Ström, P.; Lejeune, A.

    2015-06-15

    Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied.

  4. VUV emission spectroscopy diagnostics of a 14 GHz ECR negative hydrogen ion source

    SciTech Connect

    Tamura, R. Ichikawa, T.; Kasuya, T.; Wada, M.; Nishiura, M.; Shimozuma, T.

    2015-04-08

    Vacuum Ultra Violet(VUV) emission from a 4 cm diameter 2 cm long compact ion source excited by 14 GHz microwave has been investigated. Intensity ratio of band spectrum emission near Ly-α to Ly-α line spectrum is determined from the measured spectrum. which shows preferential excitation of molecules near the entrance of microwave input power. The ratio does not depend strongly upon pressure nor the input microwave power when the intensity is integrated over the volume of the plasma. The spatial distribution of the spectrum intensity ratio exhibits concentrations near microwave inlet and the opposite side where the microwave matching structure is located. The ratio at these peripheral regions is about two times as high as that of the central region. The ratio increased in proportion to the ion source pressure up to about 3.0 Pa, indicating efficient production of high energy electrons by ECR up to this pressure.

  5. 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.

  6. Rapid variations of balmer line strengths in the spectra of Be stars. Ph.D. Thesis; [photoelectric spectrophotometric measurements

    NASA Technical Reports Server (NTRS)

    Mcbeath, K. B.

    1974-01-01

    Low resolution photoelectric spectrophotometric measurements of the first four members of the Balmer series in the spectra of one Be and five Be (shell) stars were obtained with the 92-cm telescope and image dissecting scanner. Equivalent widths were computed for each observation, and their standard deviations from the mean values were examined. Results indicate that in three of the program stars, at least one of the Balmer lines shows significant fluctuations in equivalent width. These fluctuations amount to a few per cent of total line strength and the time scales appear to be on the order of three to thirty minutes. The fluctuations are not always present in a given star, indicating that the mechanism producing them may not be continuous. The noncontinuous and nonperiodic nature of the variations, along with their short time scale suggest some form of flare-like or shock origin for the phenomenon.

  7. Cross-correlation cosmography with intensity mapping of the neutral hydrogen 21 cm emission

    NASA Astrophysics Data System (ADS)

    Pourtsidou, A.; Bacon, D.; Crittenden, R.

    2015-11-01

    The cross-correlation of a foreground density field with two different background convergence fields can be used to measure cosmographic distance ratios and constrain dark energy parameters. We investigate the possibility of performing such measurements using a combination of optical galaxy surveys and neutral hydrogen (HI) intensity mapping surveys, with emphasis on the performance of the planned Square Kilometre Array (SKA). Using HI intensity mapping to probe the foreground density tracer field and/or the background source fields has the advantage of excellent redshift resolution and a longer lever arm achieved by using the lensing signal from high redshift background sources. Our results show that, for our best SKA-optical configuration of surveys, a constant equation of state for dark energy can be constrained to ≃8 % for a sky coverage fsky=0.5 and assuming a σ (ΩDE)=0.03 prior for the dark energy density parameter. We also show that using the cosmic microwave background as the second source plane is not competitive, even when considering a COrE-like satellite.

  8. Molecular hydrogen (H2) combustion emissions and their isotope (D/H) signatures from domestic heaters, diesel vehicle engines, waste incinerator plants, and biomass burning

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Mohn, J.; Steinbacher, M.; Bond, S. W.; Röckmann, T.; Reimann, S.

    2012-03-01

    Molecular hydrogen (H2), its stable isotope signature (δD), and the key combustion parameters carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were measured from various combustion processes. H2 in the exhaust of gas and oil-fired heaters and of waste incinerator plants was generally depleted compared to ambient intake air, while CO was significantly elevated. These findings contradict the often assumed co-occurring net H2 and CO emissions in combustion processes and suggest that previous H2 emissions from combustion may have been overestimated when scaled to CO emissions. For the heater exhausts, H2 and δD generally decrease with increasing fuel-to-air ratio, from ambient values of ∼0.5 ppm and +130‰ to 0.2 ppm and -206‰, respectively. These results are interpreted as a combination of an isotopically light H2 source from fossil fuel combustion and a D/H kinetic isotope fractionation of hydrogen in the advected ambient air during its partial removal during combustion. Diesel exhaust measurements from dynamometer test stand driving cycles show elevated H2 and CO emissions during cold-start and some acceleration phases. Their molar H2/CO ratios are <0.25, significantly smaller than those for gasoline combustion. Using H2/CO emission ratios, along with CO global emission inventories, we estimate global H2 emissions for 2000, 2005, and 2010. For road transportation (gasoline and diesel), we calculate 8.6 ± 2.1 Tg, 6.3 ± 1.5 Tg, and 4.1 ± 1.0 Tg, respectively, whereas the contribution from diesel vehicles has increased from 5% to 8% over this time. Other fossil fuel emissions are believed to be negligible but H2 emissions from coal combustion are unknown. For residential (domestic) emissions, which are likely dominated by biofuel combustion, emissions for the same years are estimated at 2.7 ± 0.7 Tg, 2.8 ± 0.7 Tg, and 3.0 ± 0.8 Tg, respectively. Our wood combustion measurements are combined with results from the literature to calculate

  9. Modeling Far-UV Fluorescent Emission Features of Warm Molecular Hydrogen in the Inner Regions of Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Hoadley, Keri; France, Kevin

    2015-01-01

    Probing the surviving molecular gas within the inner regions of protoplanetary disks (PPDs) around T Tauri stars (1 - 10 Myr) provides insight into the conditions in which planet formation and migration occurs while the gas disk is still present. We model observed far ultraviolet (FUV) molecular hydrogen (H₂) fluorescent emission lines that originate within the inner regions (< 10 AU) of 9 well-studied Classic T Tauri stars, using the Hubble Space Telescope Cosmic Origins Spectrograph (COS), to explore the physical structure of the molecular disk at different PPD dust evolutionary stages. We created a 2D radiative transfer model that estimates the density and temperature distributions of warm, inner radial H₂ (T > 1500 K) with a set of 6 free parameters and produces a data cube of expected emission line profiles that describe the physical structure of the inner molecular disk atmosphere. By comparing the modeled emission lines with COS H₂ fluorescence emission features, we estimate the physical structure of the molecular disk atmosphere for each target with the set of free parameters that best replicate the observed lines. First results suggest that, for all dust evolutionary stages of disks considered, ground-state H₂ populations are described by a roughly constant temperature T(H₂) = 2500 +/- 1000 K. Possible evolution of the density structure of the H₂ atmosphere between intact and depleting dust disks may be distinguishable, but large errors in the inferred best-fit parameter sets prevent us from making this conclusion. Further improvements to the modeling framework and statistical comparison in determining the best-fit model-to-data parameter sets are ongoing, beginning with improvements to the radiative transfer model and use of up-to-date HI Lyman α absorption optical depths (see McJunkin in posters) to better estimate disk structural parameters. Once improvements are implemented, we will investigate the possible presence of a molecular wind

  10. High Spatial Resolution Studies of Epithermal Neutron Emission from the Lunar Poles: Constraints on Hydrogen Mobility

    NASA Technical Reports Server (NTRS)

    Boynton, W. V.; Droege, G. F.; Mitrofanov, I. G.; McClanahan, T. P.; Sanin, A. B.; Litvak, M. L.; Schaffner, M.; Chin, G.; Evans, L. G.; Garvin, J. B.; Harshman, K.; Malakhov, A.; Milikh, G.; Sagdeev, R.; Starr, R.

    2012-01-01

    The data from the collimated sensors of the LEND instrument are shown to be of exceptionally high quality. Counting uncertainties are about 0.3% relative and are shown to be the only significant source of random error, thus conclusions based on small differences in count rates are valid. By comparison with the topography of Shoemaker crater, the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined. The observed epithermal-neutron suppression factor due to the hydrogen deposit in Shoemaker crater of 0.25 plus or minus 0.04 cps is consistent with the collimated field-of-view rate of 1.7 cps estimated by Mitrofanov et al. (2010a). The statistical significance of the neutron suppressed regions (NSRs) relative to the larger surrounding polar region is demonstrated, and it is shown that they are not closely related to the permanently shadowed regions. There is a significant increase in H content in the polar regions independent of the H content of the NSRs. The non-NSR H content increases directly with latitude, and the rate of increase is virtually identical at both poles. There is little or no increase with latitude outside the polar region. Various mechanisms to explain this steep increase in the non-NSR polar H with latitude are investigated, and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles.

  11. The hydrogen-poor superluminous supernova iPTF 13ajg and its host galaxy in absorption and emission

    SciTech Connect

    Vreeswijk, Paul M.; Gal-Yam, Avishay; De Cia, Annalisa; Rubin, Adam; Yaron, Ofer; Tal, David; Ofek, Eran O.; Savaglio, Sandra; Quimby, Robert M.; Sullivan, Mark; Cenko, S. Bradley; Filippenko, Alexei V.; Clubb, Kelsey I.; Perley, Daniel A.; Cao, Yi; Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos; Arcavi, Iair; Kasliwal, Mansi M.; and others

    2014-12-10

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z = 0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M {sub u,} {sub AB} = –22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2 × 10{sup 44} erg s{sup –1}, while the estimated total radiated energy is 1.3 × 10{sup 51} erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the Very Large Telescope. From Voigt profile fitting, we derive the column densities log N(Mg I) =11.94 ± 0.06, log N(Mg II) =14.7 ± 0.3, and log N(Fe II) =14.25 ± 0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs) whose progenitors are also thought to be massive stars. This suggests that the environments of hydrogen-poor SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. The neutral gas responsible for the absorption in iPTF 13ajg exhibits a single narrow component with a low velocity width, ΔV = 76 km s{sup –1}, indicating a low-mass host galaxy. No host galaxy emission lines are detected, leading to an upper limit on the unobscured star formation rate (SFR) of SFR{sub [O} {sub II]}<0.07M{sub ⊙}yr{sup −1}. Late-time imaging shows the iPTF 13ajg host galaxy to be faint, with g {sub AB} ≈ 27.0 and R {sub AB} ≥ 26.0 mag, corresponding to M {sub B,} {sub Vega} ≳ –17.7 mag.

  12. The Hydrogen-poor Superluminous Supernova iPTF 13ajg and its Host Galaxy in Absorption and Emission

    NASA Astrophysics Data System (ADS)

    Vreeswijk, Paul M.; Savaglio, Sandra; Gal-Yam, Avishay; De Cia, Annalisa; Quimby, Robert M.; Sullivan, Mark; Cenko, S. Bradley; Perley, Daniel A.; Filippenko, Alexei V.; Clubb, Kelsey I.; Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos; Arcavi, Iair; Rubin, Adam; Kasliwal, Mansi M.; Cao, Yi; Yaron, Ofer; Tal, David; Ofek, Eran O.; Capone, John; Kutyrev, Alexander S.; Toy, Vicki; Nugent, Peter E.; Laher, Russ; Surace, Jason; Kulkarni, Shrinivas R.

    2014-12-01

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z = 0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M u, AB = -22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2 × 1044 erg s-1, while the estimated total radiated energy is 1.3 × 1051 erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the Very Large Telescope. From Voigt profile fitting, we derive the column densities log N(Mg I) =11.94 ± 0.06, log N(Mg II) =14.7 ± 0.3, and log N(Fe II) =14.25 ± 0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs) whose progenitors are also thought to be massive stars. This suggests that the environments of hydrogen-poor SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. The neutral gas responsible for the absorption in iPTF 13ajg exhibits a single narrow component with a low velocity width, ΔV = 76 km s-1, indicating a low-mass host galaxy. No host galaxy emission lines are detected, leading to an upper limit on the unobscured star formation rate (SFR) of SFR_[O \\scriptsize{II]}<0.07 {M_⊙ yr-1}. Late-time imaging shows the iPTF 13ajg host galaxy to be faint, with g AB ≈ 27.0 and R AB >= 26.0 mag, corresponding to M B, Vega >~ -17.7 mag.

  13. Hydrogen sulfide gas emissions during disturbance and removal of stored spent mushroom compost.

    PubMed

    Velusami, B; Curran, T P; Grogan, H M

    2013-10-01

    Spent mushroom compost (SMC) is a by-product of the mushroom industry that is used as an agricultural fertilizer. In Europe, SMC storage and use are governed by EU Nitrates Directive 91/676/EEC to protect waterways against pollution by nitrates. A health and safety risk was identified during the removal of stored SMC for land application, as the stored SMC released high levels of toxic H2S gas into the atmosphere when disturbed. In this study, emissions of H2S were monitored at two outdoor and two indoor locations where stored SMC was being removed for land application. A repeating peak-trough pattern of H2S emissions was detected at all sites, with peaks corresponding to periods of active disturbance of SMC. The highest H2S concentrations (10 s average) detected at the SMC face were, respectively, 680 and 2083 ppm at outdoor sites 1 and 2, and 687 and 89 ppm at indoor sites 3 and 4. Higher concentrations of H2S were released from older SMC compared to newer material. Indoor-stored SMC had lower moisture content (53% to 65%) compared to outdoor-stored material (66% to 72%), while the temperature of indoor-stored SMC was higher (33 degrees C to 51 degrees C) compared to outdoor-stored material (24 degrees C to 36 degreees C). The current short-term exposure limit (STEL) of 10 ppm was exceeded at all sites except site 4, which was smaller than the other sites, indicating a significant health and safety risk associated with working in the vicinity of stored SMC when it is being actively disturbed. Results suggest that SMC stored under cover in small heaps (600 m3) emits less H2S during disturbance and removal compared to SMC stored outdoors in large heaps (> 1500 m3). This should be taken into consideration in the design, construction, and management of SMC storage facilities. Health and safety protocols should be in place at SMC storage facilities to cover the risks of exposure to toxic H2S gas during disturbance of stored SMC. PMID:24673035

  14. Anomalous hydrogen emissions from the San Andreas fault observed at the Cienega Winery, central California

    USGS Publications Warehouse

    Sato, M.; Sutton, A.J.; McGee, K.A.

    1985-01-01

    We began continuous monitoring of H2 concentration in soil along the San Andreas and Calaveras faults in central California in December 1980, using small H2/O2 fuel-cell sensors. Ten monitoring stations deployed to date have shown that anomalous H2 emissions take place occasionally in addition to diurnal changes. Among the ten sites, the Cienega Winery site has produced data that are characterized by very small diurnal changes, a stable baseline, and remarkably distinct spike-like H2 anomalies since its installation in July 1982. A major peak appeared on 1-10 November 1982, and another on 3 April 1983, and a medium peak on 1 November 1983. The occurrences of these peaks coincided with periods of very low seismicity within a radius of 50 km from the site. In order to methodically assess how these peaks are related to earthquakes, three H2 degassing models were examined. A plausible correlational pattern was obtained by using a model that (1) adopts a hemicircular spreading pattern of H2 along an incipient fracture plane from the hypocenter of an earthquake, (2) relies on the FeO-H2O reaction for H2 generation, and (3) relates the accumulated amount of H2 to the mass of serpentinization of underlying ophiolitic rocks; the mass was tentatively assumed to be proportional to the seismic energy of the earthquake. ?? 1985 Birkha??user Verlag.

  15. Estimation of hydrogen sulfide emission rates at several wastewater treatment plants through experimental concentration measurements and dispersion modeling.

    PubMed

    Llavador Colomer, Fernando; Espinós Morató, Héctor; Mantilla Iglesias, Enrique

    2012-07-01

    The management and operation of wastewater treatment plants (WWTP) usually involve the release into the atmosphere of malodorous substances with the potential to reduce the quality of life of people living nearby. In this type of facility, anaerobic degradation processes contribute to the generation of hydrogen sulfide (H2S), often at quite high concentrations; thus, the presence of this chemical compound in the atmosphere can be a good indicator of the occurrence and intensity of the olfactory impact in a specific area. The present paper describes the experimental and modelling work being carried out by CEAM-UMH in the surroundings of several wastewater treatment plants located in the Valencia Autonomous Community (Spain). This work has permitted the estimation of H2S emission rates at different WWTPs under different environmental and operating conditions. Our methodological approach for analyzing and describing the most relevant aspects of the olfactory impact consisted of several experimental campaigns involving intensive field measurements using passive samplers in the vicinity of several WWTPs, in combination with numerical simulation results from a diagnostic dispersion model. A meteorological tower at each WWTP provided the input values for the dispersion code, ensuring a good fit of the advective component and therefore more confidence in the modelled concentration field in response to environmental conditions. Then, comparisons between simulated and experimental H2S concentrations yielded estimates of the global emission rate for this substance at several WWTPs at different time periods. The results obtained show a certain degree of temporal and spatial (between-plant) variability (possibly due to both operational and environmental conditions). Nevertheless, and more importantly, the results show a high degree of uniformity in the estimates, which consistently stay within the same order of magnitude. PMID:22866577

  16. Measurement and analysis of ammonia and hydrogen sulfide emissions from a mechanically ventilated swine confinement building in North Carolina

    NASA Astrophysics Data System (ADS)

    Blunden, Jessica; Aneja, Viney P.; Westerman, Phillip W.

    Emissions of atmospheric ammonia-nitrogen (NH 3-N, where NH 3-N=( {14}/{17})NH 3) and hydrogen sulfide (H 2S) were measured from a finishing swine confinement house at a commercial pig farm in eastern North Carolina. Continuous simultaneous NH 3-N and H 2S emissions were made for ˜1-week period during four different seasons. The number of pigs contained in the house varied from ˜850 to 900 with average weights ranging from ˜38 to 88 kg. Average NH 3-N concentrations were highest during the winter and spring sampling periods, 8.91±4.61 and 8.44±2.40 ppm, respectively, and lower during the summer and fall, 2.45±1.14 and 4.27±0.71 ppm, respectively. Measured average H 2S concentrations were 673±282, 429±223, 47±18, and 304±88 ppb during winter, spring, summer, and fall, respectively. Generally, the H 2S concentrations were approximately an order of magnitude less than NH 3-N during winter, spring, and fall, and two orders of magnitude smaller during the summer season. The average ambient temperature ranged from 5.5 to 22.3 °C while the average barn temperature measured at the outlet fans ranged from 19.0 to 26.0 °C in the winter and summer, respectively. The average fan ventilation rates varied from 253 m 3 min -1 during the fall sampling period to 1024 m 3 min -1 during summer. Calculated total emission rates for both NH 3-N and H 2S were highest during the spring, 4519±1639 g N day -1 and 481±142 g day -1, respectively. Emissions were lowest during the fall season for NH 3-N (904±568 g N day -1) and the summer season for H 2S (82±49 g day -1). Normalized NH 3-N emission rates were highest in winter and spring (33.6±21.9 and 30.6±11.1 g N day -1 AU -1, where 1 AU (animal unit)=500 kg) and lowest during summer and fall (24.3±12.4 and 11.8±7.4 g N day -1 AU -1). Normalized H 2S emissions were highest during the winter and spring seasons (4.2±2.1 and 3.3±1.0 g day -1 AU -1) and were lowest in summer and fall (1.2±0.7 and 1.7±0.5 g day -1 AU -1).

  17. Discovery of an activity cycle in the solar analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates

    NASA Astrophysics Data System (ADS)

    Flores, M.; González, J. F.; Jaque Arancibia, M.; Buccino, A.; Saffe, C.

    2016-05-01

    Context. Most stellar activity cycles similar to that found in the Sun have been detected by using the chromospheric Ca ii H&K lines as stellar activity proxies. However, it is unclear whether such activity cycles can be identified using other optical lines. Aims: We aim to detect activity cycles in solar-analog stars and determine whether they can be identified through other optical lines, such as Fe II and Balmer lines. We study the solar-analog star HD 45184 using HARPS spectra. The temporal coverage and high quality of the spectra allow us to detect both long- and short-term activity variations. Methods: We analysed the activity signatures of HD 45184 by using 291 HARPS spectra obtained between 2003 and 2014. To search for line-core flux variations, we focused on Ca ii H&K and Balmer Hα and Hβ lines, which are typically used as optical chromospheric activity indicators. We calculated the HARPS-S index from Ca ii H&K lines and converted it into the Mount Wilson scale. In addition, we also considered the equivalent widths of Balmer lines as activity indicators. Moreover, we analysed the possible variability of Fe ii and other metallic lines in the optical spectra. The spectral variations were analysed for periodicity using the Lomb-Scargle periodogram. Results: We report for the first time a long-term 5.14-yr activity cycle in the solar-analog star HD 45184 derived from Mount Wilson S index. This makes HD 45184 one of most similar stars to the Sun with a known activity cycle. The variation is also evident in the first lines of the Balmer series, which do not always show a correlation with activity in solar-type stars. Notably, unlike the solar case, we also found that the equivalent widths of the high photospheric Fe ii lines (4924 Å, 5018 Å and 5169 Å) are modulated (±2 mÅ) by the chromospheric cycle of the star. These metallic lines show variations above 4σ in the rms spectrum, while some Ba ii and Ti ii lines present variations at 3σ level, which

  18. Relation between Starlight and Nebular Emission Lines of Star-Forming Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, Hong-Lin; Zhou, Hong-Yan; Wang, Ting-Gui; Zhuang, Zhen-Quan; Dong, Xiao-Bo; Wang, Jun-Xian; Li, Cheng

    2005-06-01

    We present an exercise that intends to establish a relationship between the strength of nebular emission lines and optical stellar features in the spectrum of a galaxy. After accurately subtracting the stellar continuum and the underlying stellar absorption, we made reliable measurements of the emission lines of all the galaxies in the Sloan Digital Sky Survey Data Release 2 (SDSS DR2). More than 4000 star-forming galaxies with high S/N ratio of both the stellar spectrum and the emission lines are selected. These galaxy spectra are fitted with the 10 PCs of Yip et al., after all the emission line regions have been filtered out. We find that the flux of hydrogen Balmer emission lines, Hα and Hβ can be well recovered from the PCs, while the metal lines are not well reproduced. The fluxes of Hα and Hβ measured from the PC-reconstructed spectra and from the observed spectra agree well with an rms scatter of only ~0.1 dex. This result suggests that, with moderate spectral resolution and S/N ratio, the optical stellar spectrum of a galaxy can serve as an indicator of star formation rate.

  19. Vacuum ultraviolet emission spectrum measurement of a microwave-discharge hydrogen-flow lamp in several configurations: Application to photodesorption of CO ice

    SciTech Connect

    Chen, Y.-J.; Wu, C.-Y. R.; Chuang, K.-J.; Chu, C.-C.; Yih, T.-S.; Muñoz Caro, G. M.; Nuevo, M.; Ip, W.-H.

    2014-01-20

    We report measurements of the vacuum ultraviolet (VUV) emission spectra of a microwave-discharge hydrogen-flow lamp (MDHL), a common tool in astrochemistry laboratories working on ice VUV photoprocessing. The MDHL provides hydrogen Ly-α (121.6 nm) and H{sub 2} molecular emission in the 110-180 nm range. We show that the spectral characteristics of the VUV light emitted in this range, in particular the relative proportion of Ly-α to molecular emission bands, strongly depend on the pressure of H{sub 2} inside the lamp, the lamp geometry (F type versus T type), the gas used (pure H{sub 2} versus H{sub 2} seeded in He), and the optical properties of the window used (MgF{sub 2} versus CaF{sub 2}). These different configurations are used to study the VUV irradiation of CO ice at 14 K. In contrast to the majority of studies dedicated to the VUV irradiation of astrophysical ice analogs, which have not taken into consideration the emission spectrum of the MDHL, our results show that the processes induced by photons in CO ice from a broad energy range are different and more complex than the sum of individual processes induced by monochromatic sources spanning the same energy range, as a result of the existence of multistate electronic transitions and discrepancy in absorption cross sections between parent molecules and products in the Ly-α and H{sub 2} molecular emission ranges.

  20. Comparison of Optical Emission Spectroscopy and Cavity Ring-Down Spectroscopy in Large-Scaled Negative-Ion Source

    SciTech Connect

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

    2011-09-26

    Optical emission spectroscopy (OES) and cavity ring-down spectroscopy (CRDS) systems are installed in a 1/3-scaled negative hydrogen-ion source at the National Institute for Fusion Science testbed to investigate the dynamics of H{sup -} ions in the extraction region near the plasma grid. The signal form of the H{sup -} ion density rapidly drops after beam extraction on applying a low-bias voltage. A similar signal drop appears in the intensity of the hydrogen Balmer-line emission measured by OES and is caused by decreasing atomic hydrogen produced by mutual neutralization effects between H{sup -} and H{sup +}. Shot trend of the beam currents are similar to the H{sup -} density and H{sub {alpha}}/H{sub {beta}} in the extraction region, which increases twice as large immediately after Cs seeding. We observe a linear correlation between the H{sup -} density and the inclination of H{sub {alpha}}/H{sub {beta}} which allows for experimentally benchmarking the OES measurement with that of CRDS. Thus, this approach is used for estimating the H{sup -} density by OES in negative-ion sources for high-energy neutral beam injector.

  1. Molecular hydrogen (H2) combustion emissions and their isotope (D/H) signatures from domestic heaters, diesel vehicle engines, waste incinerator plants, and biomass burning

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Mohn, J.; Steinbacher, M.; Bond, S. W.; Röckmann, T.; Reimann, S.

    2012-07-01

    Molecular hydrogen (H2), its stable isotope signature (δD), and the key combustion parameters carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were measured from various combustion processes. H2 in the exhaust of gas and oil-fired heaters and of waste incinerator plants was generally depleted compared to ambient intake air, while CO was significantly elevated. These findings contradict the often assumed co-occurring net H2 and CO emissions in combustion processes and suggest that previous H2 emissions from combustion may have been overestimated when scaled to CO emissions. For the gas and oil-fired heater exhausts, H2 and δD generally decrease with increasing CO2, from ambient values of ~0.5 ppm and +130‰ to 0.2 ppm and -206‰, respectively. These results are interpreted as a combination of an isotopically light H2 source from fossil fuel combustion and a D/H kinetic isotope fractionation of hydrogen in the advected ambient air during its partial removal during combustion. Diesel exhaust measurements from dynamometer test stand driving cycles show elevated H2 and CO emissions during cold-start and some acceleration phases. While H2 and CO emissions from diesel vehicles are known to be significantly less than those from gasoline vehicles (on a fuel-energy base), we find that their molar H2/CO ratios (median 0.026, interpercentile range 0.12) are also significantly less compared to gasoline vehicle exhaust. Using H2/CO emission ratios, along with CO global emission inventories, we estimate global H2 emissions for 2000, 2005, and 2010. For road transportation (gasoline and diesel), we calculate 8.3 ± 2.2 Tg, 6.0 ± 1.5 Tg, and 3.8 ± 0.94 Tg, respectively, whereas the contribution from diesel vehicles is low (0.9-1.4%). Other fossil fuel emissions are believed to be negligible but H2 emissions from coal combustion are unknown. For residential (domestic) emissions, which are likely dominated by biofuel combustion, emissions for the same years are

  2. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    NASA Astrophysics Data System (ADS)

    Shi, Xiheng; Zhou, Hongyan; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-03-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of Hβ shows a variation of more than 5σ at a high velocity portion (\\gt 3000 {km} {{{s}}}-1) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He i and optical Fe ii absorptions (λ4233 from b4P5/2 level and λ5169 from a6S5/2) at the same velocity. These Fe ii lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of n({{H}})≈ {10}9.1 {{cm}}-3 and a column density of {N}{col}({{H}})≈ {10}23 {{cm}}-2 for the BOSS data, but the model fails to predict the variations of ionic column densities between the SDSS and BOSS observations if changes in ionizing flux are assumed. We thus propose transverse motion of the absorbing gas being the cause of the observed broad Balmer absorption line variability. In fact, we find that the changes in covering factors of the absorber can well-reproduce all of the observed variations. The absorber is estimated ∼0.94 pc away from the central engine, which is where the outflow likely experiences deceleration due to the collision with the surrounding medium. This scheme is consistent with the argument that LoBAL QSOs may represent the transition from obscured star-forming galaxies to classic QSOs.

  3. A NEW SUB-PERIOD-MINIMUM CATACLYSMIC VARIABLE WITH PARTIAL HYDROGEN DEPLETION AND EVIDENCE OF SPIRAL DISK STRUCTURE

    SciTech Connect

    Littlefield, C.; Garnavich, P.; Magno, K.; Applegate, A.; Pogge, R.; Irwin, J.; Marion, G. H.; Kirshner, R.; Vinko, J.

    2013-06-15

    We present time-resolved spectroscopy and photometry of CSS 120422:111127+571239 (=SBS 1108+574), a recently discovered SU UMa-type dwarf nova whose 55 minute orbital period is well below the cataclysmic variable (CV) period minimum of {approx}78 minutes. In contrast with most other known CVs, its spectrum features He I emission of comparable strength to the Balmer lines, implying a hydrogen abundance less than 0.1 of long-period CVs-but still at least 10 times higher than that in AM CVn stars. Together, the short orbital period and remarkable helium-to-hydrogen ratio suggest that mass transfer in CSS 120422 began near the end of the donor star's main-sequence lifetime, meaning that this CV is a strong candidate progenitor of an AM CVn system as described by Podsiadlowski et al. Moreover, a Doppler tomogram of the H{alpha} line reveals two distinct regions of enhanced emission. While one is the result of the stream-disk impact, the other is probably attributable to spiral disk structure generated when material in the outer disk achieves a 2:1 orbital resonance with respect to the donor.

  4. Optical emission spectroscopy of the Linac4 and superconducting proton Linac plasma generators.

    PubMed

    Lettry, J; Fantz, U; Kronberger, M; Kalvas, T; Koivisto, H; Komppula, J; Mahner, E; Schmitzer, C; Sanchez, J; Scrivens, R; Midttun, O; Myllyperkiö, P; O'Neil, M; Pereira, H; Paoluzzi, M; Tarvainen, O; Wünderlich, D

    2012-02-01

    CERN's superconducting proton Linac (SPL) study investigates a 50 Hz high-energy, high-power Linac for H(-) ions. The SPL plasma generator is an evolution of the DESY ion source plasma generator currently operated at CERN's Linac4 test stand. The plasma generator is a step towards a particle source for the SPL, it is designed to handle 100 kW peak RF-power at a 6% duty factor. While the acquisition of an integrated hydrogen plasma optical spectrum is straightforward, the measurement of a time-resolved spectrum requires dedicated amplification schemes. The experimental setup for visible light based on photomultipliers and narrow bandwidth filters and the UV spectrometer setup are described. The H(α), H(β), and H(γ) Balmer line intensities, the Lyman band and alpha transition were measured. A parametric study of the optical emission from the Linac4 ion source and the SPL plasma generator as a function of RF-power and gas pressure is presented. The potential of optical emission spectrometry coupled to RF-power coupling measurements for on-line monitoring of short RF heated hydrogen plasma pulses is discussed. PMID:22380238

  5. 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. PMID:17272235

  6. The potential of hydrogen lines for the spectropolarimetry of the solar corona

    NASA Astrophysics Data System (ADS)

    Vial, Jean-Claude; Chane-Yook, Martine

    2016-07-01

    Neutral Hydrogen lines have been detected in the hot and ionized solar corona as early as 1970 (Gabriel et al. 1971) and since then with the Spartan and UVCS/SoHO space experiments. Moreover, because of the sensitivity of the Lyman lines to the Hanle effect (Bommier and Sahal-Brechot 1982, Trujillo Bueno et al. 2005), polarization measurements in these lines could lead to the diagnostic of weak magnetic fields in the corona (Derouich et al. 2010), a challenge which has led to various space mission proposals such as LYOT/SMESE or MASC. Our investigation concerns the computation of the emission in 10 selected lines of Hydrogen (Lyman, Balmer, and Paschen) taking into account the proper computation of the NonLTE H ionization and atomic levels populations. We present the results for three different coronal models (streamer, quiet Sun and coronal hole) in terms of profiles and absolute intensities at altitudes varying from 1.05 to 1.9 solar radius. These spectrophotometric results could help for the determination of the space and ground-based polarimetric instrumentation best suited for the measurement of the coronal magnetic field.

  7. Achievement of high atomic hydrogen densities in cylindrical rf plasmas with magnetic field

    NASA Astrophysics Data System (ADS)

    Fantz, Ursel; Briefi, Stefan

    2014-10-01

    Cylindrical rf plasmas in hydrogen with and without an axial magnetic field of up to 120 G are investigated in the pressure range of 0.3 to 10 Pa. The atomic hydrogen density is determined with optical emission spectroscopy, analyzing the Balmer lines and the molecular radiation (Fulcher band). The results obtained by using different coil geometries (4 to 6 turn windings and Nagoya type antenna) as well as different diameters (10 cm and 25 cm) of a quartz, aluminum oxide or aluminum nitride cylinder are compared. RF powers of up to 600 W at a frequency of 13.56 MHz are available for the 10 cm configuration, whereas up to 70 kW power at 1 MHz are used for the 25 cm cylinder. Density ratios of atoms to molecules of up to 0.3 are achieved in both configurations, whereby the achievement in the high power setup is limited by neutral depletion. The influence of the wall material on the atomic densities, and thus the recombination coefficient, will be pointed out.

  8. Star formation in NGC 4449: MAMA-detector UV imagery and Fabry-Perot Balmer-line imagery

    NASA Technical Reports Server (NTRS)

    Hill, Robert S.; Home, Allen T.; Smith, Andrew M.; Bruhweiler, Fred C.; Cheng, K.P.; Hintzen, Paul M. N.; Oliversen, Ronald J.

    1994-01-01

    Using far-ultraviolet (FUV) and Balmer-line imagery, we investigate the star formation history of 22 large OB complexes in the Magellanic irregular galaxy NGC 4449. The FUV luminosity of NGC 4449 is comparable to those of late-type spirals and is greater than that of the LMC by approximately 2.4 mag, indicating substantial star formation in the last 10(exp 8) yr. FUV data were taken using a sounding-rocket telescope with a Multianode Microchannel Array (MAMA) detector, and Balmer-line data were taken using the Goddard Fabry-Perot Imager. The resulting imagery shows bright, roughly coincident FUV and H alpha sources throughout the extent of the visible galaxy. We model these sources using cluster-evolution codes. Although all sources are a few Myr old, clear age differences are found. In particular, several of the most recently active star formation regions are located together in the galaxy's northern periphery, which is apparently coincident with a large H I reservoir. The brightest and most massive OB complexes are found along the northeast-southwest surface brightness ridgeline (the 'bar'). Over the entire galaxy, star formation rates are consistent on timescales of 10(exp 6), 10(exp 8), and 10(exp 9) yr. A history of recent star formation is suggested with two main episodes, one predominantly in the bar ending approximately 5 Myr ago, and an ongoing one associated with an observed H I cloud.

  9. The MOSDEF Survey: Measurements of Balmer Decrements and the Dust Attenuation Curve at Redshifts z ~ 1.4–2.6

    NASA Astrophysics Data System (ADS)

    Reddy, Naveen A.; Kriek, Mariska; Shapley, Alice E.; Freeman, William R.; Siana, Brian; Coil, Alison L.; Mobasher, Bahram; Price, Sedona H.; Sanders, Ryan L.; Shivaei, Irene

    2015-06-01

    We present results on the dust attenuation curve of z ∼ 2 galaxies using early observations from the MOSFIRE Deep Evolution Field survey. Our sample consists of 224 star-forming galaxies with zspec = 1.36–2.59 and high signal-to-noise ratio measurements of Hα and Hβ obtained with Keck/MOSFIRE. We construct composite spectral energy distributions (SEDs) of galaxies in bins of Balmer decrement to measure the attenuation curve. We find a curve that is similar to the SMC extinction curve at λ ≳ 2500 Å. At shorter wavelengths, the shape is identical to that of the Calzetti et al. relation, but with a lower normalization. Hence, the new attenuation curve results in star formation rates (SFRs) that are ≈ 20% lower, and stellar masses that are {Δ }{log}({M}*{/M}ȯ )≃ 0.16 dex lower, than those obtained with the Calzetti relation. We find that the difference in the total attenuation of the ionized gas and stellar continuum correlates strongly with SFR, such that for dust-corrected SFRs ≳ 20 M⊙ yr‑1, assuming a Chabrier initial mass function, the nebular emission lines suffer an increasing degree of obscuration relative to the continuum. A simple model that can account for these trends is one in which the UV through optical stellar continuum is dominated by a population of less-reddened stars, while the nebular line and bolometric luminosities become increasingly dominated by dustier stellar populations for galaxies with large SFRs, as a result of the increased dust enrichment that accompanies such galaxies. Consequently, UV- and SED-based SFRs may underestimate the total SFR at even modest levels of ≈20 M⊙ yr‑1. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

  10. Macro-System Model: A Federated Object Model for Cross-Cutting Analysis of Hydrogen Production, Delivery, Consumption and Associated Emissions; Preprint

    SciTech Connect

    Ruth, M.; Diakov, V.; Goldsby, M. E.; Sa, T. J.

    2010-12-01

    It is commonly accepted that the introduction of hydrogen as an energy carrier for light-duty vehicles involves concomitant technological development of infrastructure elements, such as production, delivery, and consumption, all associated with certain emission levels. To analyze these at a system level, the suite of corresponding models developed by the United States Department of Energy and involving several national laboratories is combined in one macro-system model (MSM). The macro-system model is being developed as a cross-cutting analysis tool that combines a set of hydrogen technology analysis models. Within the MSM, a federated simulation framework is used for consistent data transfer between the component models. The framework is built to suit cross-model as well as cross-platform data exchange and involves features of 'over-the-net' computation.

  11. Emissions of ammonia, carbon dioxide, and hydrogen sulfide from swine wastewater during and after acidification treatment: effect of pH, mixing and aeration.

    PubMed

    Dai, X R; Blanes-Vidal, V

    2013-01-30

    This study aimed at evaluating the effect of swine slurry acidification and acidification-aeration treatments on ammonia (NH(3)), carbon dioxide (CO(2)) and hydrogen sulfide (H(2)S) emissions during slurry treatment and subsequent undisturbed storage. The study was conducted in an experimental setup consisting of nine dynamic flux chambers. Three pH levels (pH = 6.0, pH = 5.8 and pH = 5.5), combined with short-term aeration and venting (with an inert gas) treatments were studied. Acidification reduced average NH(3) emissions from swine slurry stored after acidification treatment compared to emissions during storage of non-acidified slurry. The reduction were 50%, 62% and 77% when pH was reduce to 6.0, 5.8 and 5.5, respectively. However, it had no significant effect on average CO(2) and H(2)S emissions during storage of slurry after acidification. Aeration of the slurry for 30 min had no effect on average NH(3), CO(2) and H(2)S emissions both during the process and from stored slurry after venting treatments. During aeration treatment, the NH(3), CO(2) and H(2)S release pattern observed was related to the liquid turbulence caused by the gas bubbles rather than to biological oxidation processes in this study. PMID:23246907

  12. A comprehensive study of H emission in a TEA CO2 laser-induced helium gas plasma for highly sensitive analysis of hydrogen in metal samples

    NASA Astrophysics Data System (ADS)

    Lie, Zener Sukra; Khumaeni, Ali; Niki, Hideaki; Kurihara, Kazuyoshi; Kurniawan, Koo Hendrik; Hedwig, Rinda; Fukumoto, Ken-ichi; Kagawa, Kiichiro; Lee, Yong Inn

    2012-07-01

    Our previous work on an innovative method of hydrogen (H) analysis using the specific characteristics of a TEA CO2 laser, "selective detection method of H", has been improved to realize a high H sensitive analysis with a detection limit of several µg/g. For this purpose, first, we clarified the origin of the H emission disturbance coming from H2O molecules; namely, we showed that most of the H emission came from H2O on the metal surface and not from H2O existing in the surrounding gas when we formed a laser-induced gas plasma. Second, the difference in the emission characteristics between the H emission from H2O on the metal surface and H emission from inside in sample was studied to determine the optimum gating time of the optical multi-channel analyzer (OMA). Third, the gas plasma was totally covered by fresh helium gas using a big pipe (5 mm in diameter) and by flowing a high amount of He (10 l/min). Also, we demonstrated that our methods could potentially be applied to H analysis in steel samples, where an H analysis with a sensitivity of less than 1 µg/g is required without employing a heating process, by removing H2O on the sample surface with the aid of defocused TEA CO2 laser irradiation. Thus, we stress that our method can be used for a highly sensitive, in-situ analysis of H for metal samples.

  13. Measurement of anomalously strong emission from the 1s-9p transition in the spectrum of H-like phosphorus following charge exchange with molecular hydrogen.

    PubMed

    Leutenegger, M A; Beiersdorfer, P; Brown, G V; Kelley, R L; Kilbourne, C A; Porter, F S

    2010-08-01

    We have measured K-shell x-ray spectra of highly ionized argon and phosphorus following charge exchange with molecular hydrogen at low collision energy in an electron beam ion trap using an x-ray calorimeter array with ∼6  eV resolution. We find that the emission at the high end of the Lyman series is greater by a factor of 2 for phosphorus than for argon, even though the measurement was performed concurrently and the atomic numbers are similar. This does not agree with current theoretical models and deviates from the trend observed in previous measurements. PMID:20867978

  14. Measurement of Anomalously Strong Emission from the 1s-9p Transition in the Spectrum of H-like Phosphorus Following Charge Exchange with Molecular Hydrogen

    NASA Technical Reports Server (NTRS)

    Leutenegger, M. A.; Beiersdorfer, P.; Brown, G. V.; Kelley, R. L.; Porter, F. S.

    2010-01-01

    We have measured K-shell x-ray spectra of highly ionized argon and phosphorus following charge exchange with molecular hydrogen at low collision energy in an electron beam ion trap using an x-ray calorimeter array with approx.6 eV resolution. We find that the emission at the high-end of the Lyman series is greater by a factor of two for phosphorus than for argon, even though the measurement was performed concurrently and the atomic numbers are similar. This does not agree with current theoretical models and deviates from the trend observed in previous measurements.

  15. Hydrogen Lines in Mira Stars Through Interferometry and Polarimetry

    NASA Astrophysics Data System (ADS)

    Fabas, N.; Chiavassa, A.; Millour, F.; Wittkowski, M.

    2015-12-01

    Balmer lines in emission are the most prominent features in Mira stars spectra and have a strong potential as a proxy to study the lower atmosphere's dynamics. In Fabas et al. ([1]), we accumulated spectropolarimetric observations of Balmer lines in emission. As the shock is propagating outwards, linear polarization rate increases and the angle of this polarization evolves. Assuming that linear polarization arises from anisotropic scattering, it has the potential of telling us about the geometric structure of the shock as it propagates and the study of such atmospheric structures can typically be performed with interferometry. In 2012, AMBER data on the Mira star omicron Ceti were collected in which the Brackett γ line is studied. The data show signatures in the interferometric observables around this line. Olivier Chesneau was in the jury evaluating the PhD thesis of N. Fabas and he was seduced by the idea to study these shock waves with interferometry and use polarimetry as a complementary study.

  16. The molecular hydrogen emission around L1551 IRS 5 - Shock-heated molecular gas at the base of the molecular outflow

    NASA Technical Reports Server (NTRS)

    Yamashita, Takuya; Tamura, Motohide

    1992-01-01

    Spatially resolved observations of the v = 1-0 S(1) molecular hydrogen emission toward L1551 IRS 5 using the grating spectrometer at KPNO are presented. The S(1) emission consists of a ridge component extending toward west along the optical jet from its peak on IRS 5 and a diffuse component which traces the innermost region of the cavity enclosed by the molecular outflow. The ridge component represents shock-heated molecular gas at the root of the optical jet. The diffuse component is too bright to be of scattered origin; it most likely arises from shock-heated gas within the cavity and could represent an acceleration process of the molecular outflow.

  17. Laser-induced carbon plasma emission spectroscopic measurements on solid targets and in gas-phase optical breakdown

    SciTech Connect

    Nemes, Laszlo; Keszler, Anna M.; Hornkohl, James O.; Parigger, Christian

    2005-06-20

    We report measurements of time- and spatially averaged spontaneous-emission spectra following laser-induced breakdown on a solid graphite/ambient gas interface and on solid graphite in vacuum, and also emission spectra from gas-phase optical breakdown in allene C3H4 and helium, and in CO2 and helium mixtures. These emission spectra were dominated by CII (singly ionized carbon), CIII (doubly ionized carbon), hydrogen Balmer beta (H{sub b}eta), and Swan C2 band features. Using the local thermodynamic equilibrium and thin plasma assumptions, we derived electron number density and electron temperature estimates. The former was in the 1016 cm{sup -3} range, while the latter was found to be near 20000 K. In addition, the vibration-rotation temperature of the Swan bands of the C2 radical was determined to be between 4500 and 7000 K, using an exact theoretical model for simulating diatomic emission spectra. This temperature range is probably caused by the spatial inhomogeneity of the laser-induced plasma plume. Differences are pointed out in the role of ambient CO2 in a solid graphite target and in gas-phase breakdown plasma.

  18. Energetic Charged Particle Emission from Hydrogen-Loaded pd and ti Cathodes and its Enhancement by He-4 Implantation

    NASA Astrophysics Data System (ADS)

    Lipson, A. G.; Miley, G. H.; Lipson, A. G.; Lyakhov, B. F.; Roussetski, A. S.

    2006-02-01

    In this paper, we demonstrate reproducible emissions of energetic alphas and protons appearing in an energy range where both cosmic ray interference and possible alpha emissions from contamination (e.g., radon) is assumed to be negligible. We also show that He4 doping of Pd and Ti cathodes leads to a significant enhancement of the energetic charged particles emission (ECPE). This measurement of the emissions of energetic (MeV) particles, in a region of low background interference plus their enhancement by He4 doping provides very strong support for the existence of LENR processes in the crystalline lattice of deuterated metals.

  19. Optimized hydrogen piston engines

    SciTech Connect

    Smith, J.R.

    1994-05-10

    Hydrogen piston engines can be simultaneously optimized for improved thermal efficiency and for extremely low emissions. Using these engines in constant-speed, constant-load systems such as series hybrid-electric automobiles or home cogeneration systems can result in significantly improved energy efficiency. For the same electrical energy produced, the emissions from such engines can be comparable to those from natural gas-fired steam power plants. These hydrogen-fueled high-efficiency, low-emission (HELE) engines are a mechanical equivalent of hydrogen fuel cells. HELE engines could facilitate the transition to a hydrogen fuel cell economy using near-term technology.

  20. Measurements of Hydrogen

    NASA Astrophysics Data System (ADS)

    Ashburn, John Robert

    1990-01-01

    The H(n = 3) density matrices for hydrogen atoms resulting from 20 to 150 keV protons on helium were measured. The technique consisted of applying electric fields in the collision region to Stark mix the field-free eigenstates of H atoms and measuring the Stokes parameters of the emitted Balmer-alpha radiation as a function of the electric field. The n = 3 density matrix with 14 independent parameters associated with the newly formed hydrogen atoms could be fit to the measured Balmer- alpha signals via multivariate regression. The theoretical signal responses used for the fit were determined by fully modeling the collision region and calculating the transition amplitudes of the Stark-mixed hydrogenic states. Significant improvements in the measuring apparatus and in the analysis associated with the fit of the density matrix to the optical signals have reduced systematic errors which were present in the previous investigation. The improvements include a modified optical system, which was automated and calibrated with a well defined viewing region. The performance of four different polarimeters was investigated with the optical system. Also, the background subtraction technique was improved with the addition of an automated gas handling system. Improvements were also implemented in the design of the electrodes which were used for the applied electric fields. Nonuniformities which were present in the electric field were determined by a numerical model and were incorporated into the analysis. The analysis which determined the theoretical signal responses was extensively modified and it was found that H(n = 4) cascade was the most critical limiting factor for the accuracy of the results. An agreement analysis which utilized Hotelling's T^2 statistic determined that smaller systematic errors do remain and that the results are less reproducible at the lower energies studied. However, the results were improved by combining and analyzing the axial and transverse field data

  1. Ultraluminous Star-forming Galaxies and Extremely Luminous Warm Molecular Hydrogen Emission at z = 2.16 in the PKS 1138-26 Radio Galaxy Protocluster

    NASA Astrophysics Data System (ADS)

    Ogle, P.; Davies, J. E.; Appleton, P. N.; Bertincourt, B.; Seymour, N.; Helou, G.

    2012-05-01

    A deep Spitzer Infrared Spectrograph map of the PKS 1138-26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including Hα-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of ~500-1100 M ⊙ yr-1 are estimated from the 7.7 μm PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of Hα is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H2 0-0 S(3)) = 1.4 × 1044 erg s-1 (3.7 × 1010 L ⊙), ~20 times more luminous than any previously known H2 emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 × 106-2 × 109 M ⊙ of T > 300 K molecular gas, which may be heated by the PKS 1138-26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H2 at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected.

  2. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  3. Magnetospheric accretion models for T Tauri stars. 1: Balmer line profiles without rotation

    NASA Technical Reports Server (NTRS)

    Hartmann, Lee; Hewett, Robert; Calvet, Nuria

    1994-01-01

    We argue that the strong emission lines of T Tauri stars are generally produced in infalling envelopes. Simple models of infall constrained to a dipolar magnetic field geometry explain many peculiarities of observed line profiles that are difficult, if not impossible, to reproduce with wind models. Radiative transfer effects explain why certain lines can appear quite symmetric while other lines simultaneously exhibit inverse P Cygni profiles, without recourse to complicated velocity fields. The success of the infall models in accounting for qualitative features of observed line profiles supports the proposal that stellar magnetospheres disrupt disk accretion in T Tauri stars, that true boundary layers are not usually present in T Tauri stars, and that the observed 'blue veiling' emission arises from the base of the magnetospheric accretion column.

  4. HST-COS OBSERVATIONS OF HYDROGEN, HELIUM, CARBON, AND NITROGEN EMISSION FROM THE SN 1987A REVERSE SHOCK

    SciTech Connect

    France, Kevin; Penton, Steven V.; McCray, Richard; Kirshner, Robert P.; Challis, Peter; Laming, Martin J.; Bouchet, Patrice; Garnavich, Peter M.; Fransson, Claes; Larsson, Josefin; Lundqvist, Peter; Sollerman, Jesper; Heng, Kevin; Lawrence, Stephen; Panagia, Nino; Pun, Chun S. J.; Smith, Nathan; Sonneborn, George; Sugerman, Ben; and others

    2011-12-20

    We present the most sensitive ultraviolet observations of Supernova 1987A to date. Imaging spectroscopy from the Hubble Space Telescope-Cosmic Origins Spectrograph shows many narrow ({Delta}v {approx} 300 km s{sup -1}) emission lines from the circumstellar ring, broad ({Delta}v {approx} 10-20 Multiplication-Sign 10{sup 3} km s{sup -1}) emission lines from the reverse shock, and ultraviolet continuum emission. The high signal-to-noise ratio (>40 per resolution element) broad Ly{alpha} emission is excited by soft X-ray and EUV heating of mostly neutral gas in the circumstellar ring and outer supernova debris. The ultraviolet continuum at {lambda} > 1350 A can be explained by H I two-photon (2s {sup 2} S{sub 1/2}-1s {sup 2} S{sub 1/2}) emission from the same region. We confirm our earlier, tentative detection of N V {lambda}1240 emission from the reverse shock and present the first detections of broad He II {lambda}1640, C IV {lambda}1550, and N IV] {lambda}1486 emission lines from the reverse shock. The helium abundance in the high-velocity material is He/H = 0.14 {+-} 0.06. The N V/H{alpha} line ratio requires partial ion-electron equilibration (T{sub e} /T{sub p} Almost-Equal-To 0.14-0.35). We find that the N/C abundance ratio in the gas crossing the reverse shock is significantly higher than that in the circumstellar ring, a result that may be attributed to chemical stratification in the outer envelope of the supernova progenitor. The N/C abundance may have been stratified prior to the ring expulsion, or this result may indicate continued CNO processing in the progenitor subsequent to the expulsion of the circumstellar ring.

  5. HST-COS Observations on Hydrogen, Helium, Carbon, and Nitrogen Emission from the SN 1987A Reverse Shock

    NASA Technical Reports Server (NTRS)

    France, Kevin; McCray, Richard; Penton, Steven V.; Kirshner, Robert P.; Challis, Peter; Laming, J. Martin; Bouchet, Patrice; Chevalier, Roger; Garnavich, Peter M.; Fransson, Claes; Heng, Kevin; Larsson, Josefin; Lawrence, Stephen; Lundqvist, Peter; Panagia, Nino; Pun, Chun S. J.; Smith, Nathan; Sollerman, Jesper; Sonneborn, George; Sugerman, Ben; Wheeler, J. Craig

    2011-01-01

    We present the most sensitive ultraviolet observations of Supernova 1987 A to date. Imaging spectroscopy from the Hubble Space Telescope-Cosmic Origins Spectrograph shows many narrow (Delta v approximates 300 km/s) emission lines from the circumstellar ring, broad Delta v approximates 10-20 x 10(exp 3) km/s) emission lines from the reverse shock, and ultraviolet continuum emission. The high signal-to-noise ratio (>40 per resolution element) broad Ly-alpha emission is excited by soft X-ray and EUV heating of mostly neutral gas in the circumstellar ring and outer supernova debris. The ultraviolet continuum at lambda > 1350 A can be explained by H-I two-photon (2s(exp 2)S(sub 1/2)-l(exp 2)S(sub 1/2)) emission from the same region. We confirm our earlier, tentative detection of N V lambda 1240 emission from the reverse shock and present the first detections of broad He II lambda1640, C IV lambda 1550, and N IV ] lambda1486 emission lines from the reverse shock. The helium abundance in the high-velocity material is He/H = 0.14 +/- 0.06. The N V /H alpha line ratio requires partial ion-electron equilibration (T(sub e)/T(sub p) approximately equal to 0.14-0.35). We find that the N/C abundance ratio in the gas crossing the reverse shock is significantly higher than that in the circumstellar ring, a result that may be attributed to chemical stratification in the outer envelope of the supernova progenitor. The N/C abundance may have been stratified prior to the ring expUlsion, or this result may indicate continued CNO processing in the progenitor subsequent to the expUlsion of the circumstellar ring.

  6. HST/COS SPECTRA OF DF Tau AND V4046 Sgr: FIRST DETECTION OF MOLECULAR HYDROGEN ABSORPTION AGAINST THE Ly{alpha} EMISSION LINE

    SciTech Connect

    Yang Hao; Linsky, Jeffrey L.; France, Kevin E-mail: jlinsky@jilau1.colorado.edu

    2011-03-20

    We report the first detection of molecular hydrogen (H{sub 2}) absorption in the Ly{alpha} emission line profiles of two classical T Tauri stars (CTTSs), DF Tau and V4046 Sgr, observed by the Hubble Space Telescope/Cosmic Origins Spectrograph. This absorption is the energy source for many of the Lyman-band H{sub 2} fluorescent lines commonly seen in the far-ultraviolet spectra of CTTSs. We find that the absorbed energy in the H{sub 2} pumping transitions from a portion of the Ly{alpha} line significantly differ from the amount of energy in the resulting fluorescent emission. By assuming additional absorption in the H I Ly{alpha} profile along our light of sight, we can correct the H{sub 2} absorption/emission ratios so that they are close to unity. The required H I absorption for DF Tau is at a velocity close to the radial velocity of the star, consistent with H I absorption in the edge-on disk and interstellar medium. For V4046 Sgr, a nearly face-on system, the required absorption is between +100 km s{sup -1} and +290 km s{sup -1}, most likely resulting from H I gas in the accretion columns falling onto the star.

  7. Electron Emission From Slightly Oxidized Delta-stabilized Plutonium Generated by its Radioactivity, and Radiation Induced Ionization and Dissociation of Hydrogen at its Surface

    SciTech Connect

    Siekhaus, W J; Nelson, A J

    2011-10-26

    Energy dependent electron emission between zero and 1.4 keV generated by the natural reactivity of plutonium was measured by an electrostatic spectrometer with known acceptance angle and acceptance area. The electron spectral intensity decreases continuously except for a distinctive feature of unknown origin at approximately 180eV. The spectrum was converted to energy dependent electron flux (e/cm{sup 2} s) using the assumption that the emission has a cosine angular distribution. The energy dependent electron mean free path in gases and literature cross sections for electron induced reactions were used to determine the number of ionization and dissociation reactions per cm{sup 2} second, found to be about 8*10{sup 8}/cm{sup 2}s and 1.5*10{sup 8}/cm{sup 2}s, respectively, for hydrogen. These results are to be used with caution until complementary measurements can be made, e.g. independent measurement of the total emitted electron current, since the results here are based on the assumption that the electron emission has a cosine angular distribution. That is unlikely to be correct.

  8. Development of novel and sensitive methods for the determination of sulfide in aqueous samples by hydrogen sulfide generation-inductively coupled plasma-atomic emission spectroscopy.

    PubMed

    Colon, M; Todolí, J L; Hidalgo, M; Iglesias, M

    2008-02-25

    Two new, simple and accurate methods for the determination of sulfide (S(2-)) at low levels (microgL(-1)) in aqueous samples were developed. The generation of hydrogen sulfide (H(2)S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H(2)S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was measured at 180.669nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H(2)S enhanced the sulfur signal emission. By setting a gas separator at the end of the reaction coil, reduced sulfur species in the form of H(2)S were removed from the water matrix, thus, interferences could be avoided. Alternatively, the gas separator was replaced by a nebulizer/spray chamber combination to introduce the sample matrix and reagents into the plasma. This methodology allowed the determination of both sulfide and sulfate in aqueous samples. For both methods the linear response was found to range from 5microgL(-1) to 25mgL(-1) of sulfide. Detection limits of 5microgL(-1) and 6microgL(-1) were obtained with and without the gas separator, respectively. These new methods were evaluated by comparison to the standard potentiometric method and were successfully applied to the analysis of reduced sulfur species in environmental waters. PMID:18261510

  9. Hydrogen bond-assisted aggregation-induced emission and application in the detection of the Zn(ii) ion.

    PubMed

    Wang, Dan; Li, Shu-Mu; Li, Yu-Fei; Zheng, Xiang-Jun; Jin, Lin-Pei

    2016-05-28

    The compounds of 3-aminopyridine-2-carboxylic acid with K(+) (1) and Zn(2+) (2) were found to be AIE-active. The AIE behaviours could be attributed to the restriction of intramolecular rotation (RIR) and vibration (RIV) via hydrogen bonds, resulting in rigidity enhancement of the molecules. An AIE-based fluorescence turn on chemosensor for the Zn(ii) ion has been developed in aqueous media with high selectivity and sensitivity. PMID:27126357

  10. An archetype hydrogen atmosphere problem

    NASA Technical Reports Server (NTRS)

    Athay, R. G.; Mihalas, D.; Shine, R. A.

    1975-01-01

    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.

  11. 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.).

  12. Dissociative excitation as the source of neutral atoms in hydrogen discharges

    SciTech Connect

    McNeill, D.H.

    1980-01-01

    Electron impact dissociative excitation of H/sub 2/ molecules is identified as the origin of the narrow width and structure of Balmer lines observed in various low density hydrogen discharges. On the basis of this data and estimates of the rates of competing processes in plasmas, dissociative excitation, together with other molecular reactions, is proposed as the source of neutral atoms and protons in these discharges.

  13. Materials towards carbon-free, emission-free and oil-free mobility: hydrogen fuel-cell vehicles--now and in the future.

    PubMed

    Hirose, Katsuhiko

    2010-07-28

    In the past, material innovation has changed society through new material-induced technologies, adding a new value to society. In the present world, engineers and scientists are expected to invent new materials to solve the global problem of climate change. For the transport sector, the challenge for material engineers is to change the oil-based world into a sustainable world. After witnessing the recent high oil price and its adverse impact on the global economy, it is time to accelerate our efforts towards this change. Industries are tackling global energy issues such as oil and CO2, as well as local environmental problems, such as NO(x) and particulate matter. Hydrogen is the most promising candidate to provide carbon-free, emission-free and oil-free mobility. As such, engineers are working very hard to bring this technology into the real society. This paper describes recent progress of vehicle technologies, as well as hydrogen-storage technologies to extend the cruise range and ensure the easiness of refuelling and requesting material scientists to collaborate with industry to fight against global warming. PMID:20566516

  14. A Process Based Approach to Modeling Hydrogen Sulfide Emissions Across the Air-Surface Interface of Manure from Concentrated Animal Feeding Operations

    NASA Astrophysics Data System (ADS)

    Rumsey, I. C.; Aneja, V.

    2009-12-01

    Hydrogen sulfide (H2S) emissions from concentrated animal feeding operations (CAFOs) are an important concern due to their contribution to odor and their potential to form PMfine. CAFO manure surface emissions occur from barns floors, during waste storage and treatment, and following land application. There is a need for a process based model, which will provide a method for quantifying emissions in different production, management and environmental conditions. A process based air-surface interface mass transfer model with chemical reactions was developed based on theoretical principles and related published information on H2S emissions. Different approaches were used to calculate the three main components of the model: the dissociation constant, the Henry’s law constant, and the overall mass transport coefficient. The dissociation constant was calculated based on thermodynamic principles and was corrected for the ionic strength of the manure. Similarly, the Henry’s law constant was also calculated based on thermodynamic principles. The overall mass transfer coefficient was developed using a previously published air-surface interface mass transport model, which considered the most important properties affecting mass transport to be the diffusivity of H2S in air, the air viscosity, and the air density. These parameters were modeled using dimensional analysis, which identified the variables that needed to be measured to determine the relevant constant and exponents values. By using the previously published study’s model and their measured constant and exponent values, an appropriate overall mass transfer coefficient was developed. Sensitivity analysis of the process based air-surface interface mass transfer model showed predicted fluxes to be most dependent on manure sulfide concentration and manure pH, and to a smaller extent on wind speed and manure temperature. Model predicted fluxes were compared with measured H2S flux and meteorological and physiochemical

  15. Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Bond, S. W.; Soltic, P.; Röckmann, T.

    2010-02-01

    Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO) and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD=-140‰ to δD=-195‰ upstream of the TWC but these values decreased to -270‰ to -370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ɛ) ranging from -39.8‰ to -15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of -270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

  16. Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Bond, S. W.; Soltic, P.; Röckmann, T.

    2010-06-01

    Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO), and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD = -140‰ to δD = -195‰ upstream of the TWC but these values decreased to -270‰ to -370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ɛ) ranging from -39.8‰ to -15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of -270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

  17. The ejection of shells in the stellar wind of P CYG - The most plausible explanation of the Balmer-line radial velocity variations

    NASA Astrophysics Data System (ADS)

    Markova, N.

    1986-07-01

    Our new data of the Balmer line radial velocities in the P Cygni spectrum are compared to the measurments published by de Groot (1969), Kolka (1983) and Markova (1986). The observed variations are analysed in terms of a model proposed by Kolka (1983) which implies a multiple ejection of shells in the stellar wind of P Cygni. It is shown that all data agree to an ejection time scale of about 200 days. The estimated accelerations for the three data groups are very close which supposes a stability of the ejection mechanism over an interval of about 40 yr. The radial velocities of nalmer and the FeII and FeIII (far UV) lines are compared. The identity of the Balmer and the FeII and FeIII shells is discussed.

  18. Measurement of mesoscopic Si:P delta-doped devices fabricated by rapid STM hydrogen depassivation lithography via field-emission

    NASA Astrophysics Data System (ADS)

    Rudolph, M.; Carr, S. M.; Subramania, G.; Ten Eyck, G.; Dominguez, J.; Lilly, M. P.; Carroll, M. S.; Bussmann, E.

    2014-03-01

    Recently, a method to fabricate nanoelectronic and quantum devices has been developed that utilizes scanning tunneling microscopy (STM) to place dopants (P) into Si with deterministic atomic-precision. Dopant placement is achieved via STM hydrogen depassivation lithography (HDL). Typically HDL is performed in a low-voltage tunneling mode where electrons desorb one H at a time, which requires extremely slow scan rates. Here, we introduce a high-voltage field-emission HDL, increasing patterning scan rate by an order of magnitude. Using the field-emission mode, we fabricated several HDL-patterned Si:P delta-doped devices, including a microscale multi-terminal Hall Effect device and a nanoscale quantum point contact. Low temperature transport measurements of the Hall device reveal a dopant density of 1014 cm-2, resistance of 2 k Ω/square, and mobility of 30 cm2/Vs. The quantum point contact showed a blockaded voltage range of 80 mV, comparable to other similar devices patterned using conventional HDL. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  19. VizieR Online Data Catalog: Balmer break galaxies at z<1.5 star formation (Diaz Tello+, 2016)

    NASA Astrophysics Data System (ADS)

    Diaz Tello, J.; Donzelli, C.; Padilla, N.; Akiyama, M.; Fujishiro, N.; Yoshikawa, T.; Hanami, H.

    2016-05-01

    The galaxies presented in this article come from a sample constructed to study star formation activity of massive galaxies in the redshift range z=0.1-3.0 (Diaz Tello et al., 2013ApJ...771....7D; hereafter D13). The chosen field, the SXDF (RA=02:18:00, DE=-05:00:00; Furusawa et al., 2008, Cat. J/ApJS/176/1) has the advantage that deep photometric data is available in the bands u, B, R, i, z (Subaru), J, H, K (UKIRT), and in all MIR Spitzer bands. The parent sample was selected using the λ3646 Balmer and λ4000 break features as tracers of redshift, as described by Daddi et al. (2004ApJ...617..746D), utilizing the BzK color-color diagram to select star-forming galaxies in a particular redshift range. Furthermore, we used two color-color diagrams to select star-forming galaxies in a lower redshift range than the BzK diagram; these diagrams were presented in Hanami et al. (2012PASJ...64...70H; uVi and uRJ diagrams). (1 data file).

  20. Imaging spectroscopy diagnosis of internal electron temperature and density distributions of plasma cloud surrounding hydrogen pellet in the Large Helical Device

    SciTech Connect

    Motojima, G.; Sakamoto, R.; Goto, M.; Matsuyama, A.; Yamada, H.; Mishra, J. S.

    2012-09-15

    To investigate the behavior of hydrogen pellet ablation, a novel method of high-speed imaging spectroscopy has been used in the Large Helical Device (LHD) for identifying the internal distribution of the electron density and temperature of the plasma cloud surrounding the pellet. This spectroscopic system consists of a five-branch fiberscope and a fast camera, with each objective lens having a different narrow-band optical filter for the hydrogen Balmer lines and the background continuum radiation. The electron density and temperature in the plasma cloud are obtained, with a spatial resolution of about 6 mm and a temporal resolution of 5 Multiplication-Sign 10{sup -5} s, from the intensity ratio measured through these filters. To verify the imaging, the average electron density and temperature also have been measured from the total emission by using a photodiode, showing that both density and temperature increase with time during the pellet ablation. The electron density distribution ranging from 10{sup 22} to 10{sup 24} m{sup -3} and the temperature distribution around 1 eV have been observed via imaging. The electron density and temperature of a 0.1 m plasma cloud are distributed along the magnetic field lines and a significant electron pressure forms in the plasma cloud for typical experimental conditions of the LHD.

  1. Analysis of photon emission from 50--350-keV proton impact on H{sub 2}O

    SciTech Connect

    Goldman, Benjamin D.; Timpone, Stephanie A.; Monce, Michael N.; Mitchell, Laurel; Griffin, Brian

    2011-04-15

    We have measured photon emission cross sections from neutral fragments produced by collisions of 50-350 keV protons with H{sub 2}O molecules. Balmer {alpha}-{delta} emissions from both the target and projectile were recorded. We also analyzed A {sup 2}{Sigma}{sup +}-X {sup 2}{Pi} (0,0) and (1,0) emission from the excited OH fragment produced during target dissociation. Trends in the cross sections revealed two key properties of the collision process: (1) The Bethe theory accurately describes target emission from both H and OH fragments and (2) the ratio of any two Balmer emission cross sections for both the target and projectile can be approximated by simple functions of the respective optical oscillator strengths. Finally, we provide the Bethe fit parameters necessary to calculate the target emission cross sections at all nonrelativistic impact energies.

  2. ULTRALUMINOUS STAR-FORMING GALAXIES AND EXTREMELY LUMINOUS WARM MOLECULAR HYDROGEN EMISSION AT z = 2.16 IN THE PKS 1138-26 RADIO GALAXY PROTOCLUSTER

    SciTech Connect

    Ogle, P.; Davies, J. E.; Helou, G.; Appleton, P. N.; Bertincourt, B.; Seymour, N.

    2012-05-20

    A deep Spitzer Infrared Spectrograph map of the PKS 1138-26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including H{alpha}-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of {approx}500-1100 M{sub Sun} yr{sup -1} are estimated from the 7.7 {mu}m PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of H{alpha} is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H{sub 2} 0-0 S(3)) = 1.4 Multiplication-Sign 10{sup 44} erg s{sup -1} (3.7 Multiplication-Sign 10{sup 10} L{sub Sun }), {approx}20 times more luminous than any previously known H{sub 2} emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 Multiplication-Sign 10{sup 6}-2 Multiplication-Sign 10{sup 9} M{sub Sun} of T > 300 K molecular gas, which may be heated by the PKS 1138-26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H{sub 2} at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected.

  3. pH-Regulated Reversible Transition Between Polyion Complexes (PIC) and Hydrogen-Bonding Complexes (HBC) with Tunable Aggregation-Induced Emission.

    PubMed

    Tian, Sidan; Liu, Guhuan; Wang, Xiaorui; Wu, Tao; Yang, Jinxian; Ye, Xiaodong; Zhang, Guoying; Hu, Jinming; Liu, Shiyong

    2016-02-17

    The mimicking of biological supramolecular interactions and their mutual transitions to fabricate intelligent artificial systems has been of increasing interest. Herein, we report the fabrication of supramolecular micellar nanoparticles consisting of quaternized poly(ethylene oxide)-b-poly(2-dimethylaminoethyl methacrylate) (PEO-b-PQDMA) and tetrakis(4-carboxylmethoxyphenyl)ethene (TPE-4COOH), which was capable of reversible transition between polyion complexes (PIC) and hydrogen bonding complexes (HBC) with tunable aggregation-induced emission (AIE) mediated by solution pH. At pH 8, TPE-4COOH chromophores can be directly dissolved in aqueous milieu without evident fluorescence emission. However, upon mixing with PEO-b-PQDMA, polyion complexes were formed by taking advantage of electrostatic interaction between carboxylate anions and quaternary ammonium cations and the most compact PIC micelles were achieved at the isoelectric point (i.e., [QDMA(+)]/[COO(-)] = 1), as confirmed by dynamic light scattering (DLS) measurement. Simultaneously, fluorescence spectroscopy revealed an evident emission turn-on and the maximum fluorescence intensity was observed near the isoelectric point due to the restriction of intramolecular rotation of TPE moieties within the PIC cores. The kinetic study supported a micelle fusion/fission mechanism on the formation of PIC micelles at varying charge ratios, exhibiting a quick time constant (τ1) relating to the formation of quasi-equilibrium micelles and a slow time constant (τ2) corresponding to the formation of final equilibrium micelles. Upon deceasing the pH of PIC micelles from 8 to 2 at the [QDMA(+)]/[COO(-)] molar ratio of 1, TPE-4COOH chromophores became gradually protonated and hydrophobic. The size of micellar nanoparticles underwent a remarkable decrease, whereas the fluorescence intensity exhibited a further increase by approximately 7.35-fold, presumably because of the formation of HBC micelles comprising cationic PQDMA

  4. Electron Emission from Slightly Oxidized Depleted Uranium Generated by its Own Radioactivity Measured by Electron Spectroscopy, and Electron-Induced Dissociation and Ionization of Hydrogen Near its Surface.

    SciTech Connect

    Siekhaus, W J; Nelson, A J

    2011-10-26

    Energy dependent electron emission (counts per second) between zero and 1.4 keV generated by the natural reactivity of uranium was measured by an electrostatic spectrometer with known acceptance angle and acceptance area. The electron intensity decreases continuously with energy, but at different rates in different energy regimes, suggesting that a variety of processes may be involved in producing the observed electron emission. The spectrum was converted to energy dependent electron flux (e-/cm{sup 2} s) using the assumption that the emission has a cosine angular distribution. The flux decreased rapidly from {approx}10{sup 6}/cm{sup 2}s to {approx}10{sup 5}/cm{sup 2}s in the energy range from zero to 200 eV, and then more slowly from {approx}10{sup 5}/cm{sup 2}s to {approx}3*10{sup 4}/cm{sup 2} s in the range from 200 to 1400 eV. The energy dependent electron mean free path in gases together with literature cross sections for electron induced reactions were used to determine the number of ionization and dissociation reactions per cm{sup 2}s within the inelastic mean free path of electrons, and found to be about 1.3*10{sup 8}/cm{sup 2}s and 1.5*10{sup 7}/cm{sup 2}s, respectively, for hydrogen. An estimate of the number of ionization and dissociation reactions occurring within the total range, rather than the mean free path of electrons in gases resulted in 6.2*10{sup 9}/cm{sup 2}s and 1.3*10{sup 9}/cm{sup 2}s, respectively. The total energy flux carried by electrons from the surface is suspiciously close to the total possible energy generated by one gram of uranium. A likely source of error is the assumption that the electron emission has a cosine distribution. Angular distribution measurements of the electron emission would check that assumption, and actual measurement of the total current emanating from the surface are needed to confirm the value of the current calculated in section II. These results must therefore be used with caution - until they are confirmed

  5. The a 3Σg+ - b 3Σu+ Continuum Emission from Electron Impact of Molecular Hydrogen in Saturn's Atmosphere

    NASA Astrophysics Data System (ADS)

    Hein, J. D.; Johnson, P. V.; Liu, X.; Malone, C. P.; Khakoo, M. A.

    2014-12-01

    Shemansky et al. (2009, Planetary and Space Science 57: 1659-1670) have reported observations of hydrogen atoms flowing out of the top of Saturn's sunlit thermosphere in a confined, distinct plume of ballistic and escaping orbits, and a continuous distribution of H atoms from the top of Saturn's atmosphere to at least 45 Saturn radii (RS) in the satellite orbital plane and to 25 RS azimuthally above and below the plane. These observations have revealed the importance of the excitation of H2 by low energy electrons. H2 is efficiently excited to the triplet states by low energy electrons, and all triplet excitations result in the dissociation of H2 and the production of hot H atoms. Because of this, the electron impact excitation of H2 is an important energy deposition mechanism in the upper atmospheres of Saturn and other giant planets. The a 3Σg+ - b 3Σu continuum transition, which dominates all other H2 transitions in the 168-190 nm region, provides a unique spectral window through which the triplet transition can be observed with the Cassini spacecraft. The excitation and emission cross sections of the a 3Σg+ state and other triplet states are required for the extraction of the triplet emission and excitation rates from the apparent emission rate measured by the spacecraft. These emission and excitation rates, in turn, help to determine the energy deposition rate by electron impact excitation. Unfortunately, large discrepancies exist between published measurements of the a 3Σg+ - b 3Σu continuum transition. In order to begin to address this issue, we have recently revisited the problem by measuring electron impact induced a 3Σg+ - b 3Σu emission cross sections. We have also measured direct excitation cross sections of the triplet a 3Σg+ state. Using these, we are able to partition the excitation function into its direct and cascade components. As stated above, these results will enable improved understanding of phenomena observed in Saturn's atmosphere

  6. Diffuse Hydrogen (H2) emissions from the summit crater of Pico do Fogo before the 2014-15 eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Dionis, Samara; Padrón, Eleazar; Melián, Gladys V.; Asensio-Ramos, María; Fernandes, Paulo; Barrancos, José; Rodríguez, Fátima; Padilla, Germán; Calvo, David; Hernández, Pedro A.; Silva, Sónia; Cabral, Jeremias; Bandomo, Zuleyka; Pereira, José Manuel; Semedo, Helio; Pérez, Nemesio M.

    2015-04-01

    Pico do Fogo is an active stratovolcano rising 2,829 m above sea level, situated in Fogo Island (476 km2), Cape Verde. Pico do Fogo has a long eruptive history with about 30 eruptions since its discovery (~1500 AD). On November 23, 2014 a new volcanic eruption started at the southwestern flank of the volcano after 19 years of the last eruptive event on 1995. Diffuse hydrogen (H2) emission from the summit crater of Pico do Fogo has been regularly estimated since 2007 to improve the geochemical monitoring program for the volcano surveillance. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the volcano-hydrothermal reservoir. Because of its chemical and physical characteristics, H2 moves rapidly though the crust and escapes to the atmosphere. These characteristics make H2 an excellent tracer for processes that occurs in the volcano-hydrothermal systems. The first published data on diffuse H2 degassing rate from Pico do Fogo volcano (37.3 ± 11.3 kg d-1) is related to a field work performed on February 2010 (Dionis et al., 2015). A total of seven diffuse H2 degassing surveys have been carried out during the period 2007-2014. Soil gas H2 concentration measured at 40 cm depth, allowed the computation of its emission rate in about 50 sampling sites selected in the surface environment of Pico do Fogo summit crater (0.14 km2). Both advective (convective) and diffuse components were estimated. The sampling sites were selected to cover homogeneously the study area, allowing the computation of the total H2 emission by sequential Gaussian simulation (sGs). During the study period diffuse H2 emission rate ranged between 2.9 and 163.6 kg d-1. On February 2010, it was observed the first relatively high diffuse H2 emission value which suggests the occurrence of an increase in the heat flow. However, higher observed diffuse H2 emission values than February 2010 were detected on April 2013 (75

  7. Effective temperature of A and F stars from Balmer line profiles, and the Infrared Flux Method. I. Two AM stars: the Sun and Procyon as standards.

    NASA Astrophysics Data System (ADS)

    van't Veer-Menneret, C.; Megessier, C.

    1996-05-01

    With a view of improving the effective temperature determinations, two independent methods have been used, Balmer line profile fitting and the Infrared Flux Method. The effective temperature is the first fundamental parameter to be established before doing abundance analyses of Am stars. For this purpose we used new CCD observations, and the latest versions of Kurucz codes for stellar atmospheres and Balmer line profile calculations. We used the Balmer line profile property of being gravity independent for effective temperatures less than 8500K. However examination of ATLAS9 and BALMER9 code results show that Balmer line profiles are not only dependent on the effective temperature of the atmosphere, but also on its metallicity, and are moreover strongly sensitive to its structure. In a first step we adjusted the convection parameter of atmospheres of the Sun, whose T_eff_, gravity and metallicity are well and independently established, and of Procyon used as a standard for hotter stars. The results showed that in order to fit the observed profiles, unless we increase the temperature of the Sun and Procyon by 400K, we had to lower the mixing length parameter l/H_p_ to 0.5, and to remove the overshooting option in ATLAS9 code, showing in this way a large effect of this process on computed profiles. We recomputed the models with these new options, and adopted for the two Am stars 63 Tauri and τ UMa the parameters [M/H]=+0.5 and logg=4.0 as the most reasonable working hypotheses. Concerning the Infrared Flux Method, it had to be used in its modified form, to take into account the presence of a companion, since both Am stars are single lined spectroscopic binaries. It turned out that the agreement between the effective temperatures derived independently by the two methods was very good. We combined the effective temperatures obtained from the two methods, which yielded T_eff_=7190K for 63 Tauri, and T_eff_=7045K for τ UMa, with the remarkably low internal uncertainty

  8. Hydrogen sulfide gas emissions in the human-occupied zone during disturbance and removal of stored spent mushroom compost.

    PubMed

    Velusami, B; Curran, T P; Grogan, H M

    2013-10-01

    Hydrogen sulfide (H2S) gas levels were monitored in the human-occupied zone at four spent mushroom compost (SMC) storage sites during removal of SMC for application on agricultural land. During SMC removal operations, H2S gas monitors were mounted on the outside of the tractor positioned at the SMC periphery, and worn by individual tractor drivers. The highest H2S concentrations (10 s average) detected outside the tractor, at the SMC periphery, and for the tractor driver were, respectively, 454, 249, and 100 ppm for the outdoor sites and 214, 75, and 51 ppm for the indoor sites. The highest short-term exposure values (STEV over a 15 min period) outside the tractor at the SMC periphery, and for the tractor driver were 147, 55, and 86 ppm for the outdoor sites and 19, 9, and 10 ppm for the indoor sites. The values exceeded the current maximum permissible concentration limit of 10 ppm for all the sites except for the SMC periphery and tractor driver at the indoor sites. Results suggest that H2S levels detected at indoor storage sites during SMC removal are lower compared to outdoor storage sites. Results indicate that there is a substantial health and safety risk associated with working in the vicinity of stored SMC when it is being disturbed and removed for land application, and that the risk is great for the tractor driver. This article discusses possible control measures and lists recommendations to reduce the risks. PMID:24673036

  9. Convoy electron emission from resonant coherently excited 390 MeV/u hydrogen-like Ar ions

    NASA Astrophysics Data System (ADS)

    Azuma, T.; Takabayashi, Y.; Ito, T.; Komaki, K.; Yamazaki, Y.; Takada, E.; Murakami, T.

    2003-12-01

    Energetic ions traveling through a single crystal are excited by an oscillating crystal field produced by a periodic arrangement of the atomic strings/planes, which is called Resonant Coherent Excitation (RCE). We have observed enhancement of convoy electron yields associated with RCE of 1s electron to the n=2 excited states of 390 MeV/u hydrogen-like Ar 17+ ions passing through a Si crystal in the (2 2¯ 0) planar channeling condition. Lost electrons from projectile ions due to ionization contribute to convoy electrons emitted in the forward direction with the same velocity as the projectile ions. With combination of a magnet and a thick Si solid-state detector, we measured the energy spectra of convoy electrons of about 200 keV emitted at 0°. The convoy electron yield as a function of the transition energy, i.e. the resonance profile, has a similar structure to the resonance profile observed through the ionized fraction of the emerging ions. It is explained by the fact that both enhancements are due to increase in the fraction of the excited states from which electrons are more easily ionized by target electron impact in the crystal than from the ground state.

  10. Simultaneous K- and L-band Spectroscopy of Be Stars: Circumstellar Envelope Properties from Hydrogen Emission Lines

    NASA Astrophysics Data System (ADS)

    Granada, A.; Arias, M. L.; Cidale, L. S.

    2010-05-01

    We present medium-resolution K- and L-band spectra of a sample of eight Be stars, obtained with Gemini/NIRI. The IR K and L bands contain many lines of different hydrogen series that are used as a diagnosis to the physical conditions in the circumstellar environments. We make an analysis on the optical depths of the line-forming regions based on the intensity ratios of Pfγ and Brα lines, the behavior of Humphreys' series, and the fluxes of Brα and Brγ lines. All our targets show spectroscopic and photometric long-term variability; thus, time-resolved K- and L-band spectroscopy is an ideal tool for studying the structure and evolution of the innermost regions of the envelope and to test models on the disk-forming mechanism. We note that the instrumental configuration used allowed us to obtain good quality IR observations and to take profit of Gemini band 3 observing time (allocation time for ranked programs in which the observing conditions are relaxed). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (USA), the Science and Technology Facilities Council (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  11. Control of Emissions

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor); Chung, Landy (Inventor)

    2013-01-01

    Methods and apparatus utilizing chlorine dioxide and hydrogen peroxide are useful to reduce NOx emissions, as well as SOx and mercury (or other heavy metal) emissions, from combustion flue gas streams.

  12. Modeling of Stark-Zeeman Lines in Magnetized Hydrogen Plasmas

    NASA Astrophysics Data System (ADS)

    Rosato, J.; Bufferand, H.; Capes, H.; Koubiti, M.; Godbert-Mouret, L.; Marandet, Y.; Stamm, R.

    2015-12-01

    The action of electric and magnetic fields on atomic species results in a perturbation of the energy level structure, which alters the shape of spectral lines. In this work, we present the Zeeman-Stark line shape simulation method and perform new calculations of hydrogen Lyman and Balmer lines, in the framework of magnetic fusion research. The role of the Zeeman effect, fine structure and the plasma's non-homogeneity along the line-of-sight are investigated. Under specific conditions, our results are applicable to DA white dwarf atmospheres.

  13. Effect of Amide Hydrogen Bonding Interaction on Supramolecular Self-Assembly of Naphthalene Diimide Amphiphiles with Aggregation Induced Emission.

    PubMed

    Ghule, Namdev V; La, Duong Duc; Bhosale, Rajesh S; Al Kobaisi, Mohammad; Raynor, Aaron M; Bhosale, Sheshanath V; Bhosale, Sidhanath V

    2016-04-01

    In the present work, two new naphthalene diimide (NDI) amphiphiles, NDI-N and NDI-NA, were successfully synthesized and employed to investigate their self-assembly and optical properties. For NDI-NA, which contains an amide group, aggregation-induced emission enhancement (AIEE) was demonstrated in the presence of various ratios of methylcyclohexane (MCH) in chloroform, which led to the visual color changes. This new amide-containing NDI-NA amphiphile formed nanobelt structures in chloroform/MCH (10:90, v/v) and microcup-like morphologies in chloroform/MCH (5:95, v/v). The closure of these microcups led to the formation of vesicles and microcapsules. The structural morphologies gained from the solvophobic control of NDI-NA were confirmed by various complementary techniques such as infrared spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. In the absence of the amide moiety in NDI-N, no self-assembly was observed, indicating the fundamental role of H-bonding in the self-association process. PMID:27308233

  14. Effect of Amide Hydrogen Bonding Interaction on Supramolecular Self‐Assembly of Naphthalene Diimide Amphiphiles with Aggregation Induced Emission

    PubMed Central

    Ghule, Namdev V.; La, Duong Duc; Bhosale, Rajesh S.; Al Kobaisi, Mohammad; Raynor, Aaron M.

    2016-01-01

    Abstract In the present work, two new naphthalene diimide (NDI) amphiphiles, NDI‐N and NDI‐NA, were successfully synthesized and employed to investigate their self‐assembly and optical properties. For NDI‐NA, which contains an amide group, aggregation‐induced emission enhancement (AIEE) was demonstrated in the presence of various ratios of methylcyclohexane (MCH) in chloroform, which led to the visual color changes. This new amide‐containing NDI‐NA amphiphile formed nanobelt structures in chloroform/MCH (10:90, v/v) and microcup‐like morphologies in chloroform/MCH (5:95, v/v). The closure of these microcups led to the formation of vesicles and microcapsules. The structural morphologies gained from the solvophobic control of NDI‐NA were confirmed by various complementary techniques such as infrared spectroscopy, X‐ray diffraction, and scanning and transmission electron microscopy. In the absence of the amide moiety in NDI‐N, no self‐assembly was observed, indicating the fundamental role of H‐bonding in the self‐association process. PMID:27308233

  15. Coupling and ionization effects on hydrogen spectral line shapes in dense plasmas

    NASA Astrophysics Data System (ADS)

    Calisti, A.; Bureyeva, L. A.; Lisitsa, V. S.; Shuvaev, D.; Talin, B.

    2007-06-01

    A study of hydrogen lines emitted in dense and low temperature plasmas is presented. Coupling and ionization effects in a transition from impact to quasi-static broadening for electrons are analyzed with the help of the Frequency Fluctuation Model (FFM). Electron broadening of Balmer series lines is studied for different densities and temperatures spanning a wide domain from impact to quasi-static limit. It is shown that electronic broadening makes a transition from impact to quasi-static limit depending on plasma conditions and principal quantum number. Even for the Balmer alpha line, at a density equals 1018 cm-3 and a temperature equals 1 eV, this transition occurs both in the wings and the core of the line.

  16. The contribution of dissociative processes to the production of atomic lines in hydrogen plasmas

    NASA Technical Reports Server (NTRS)

    Kunc, J. A.

    1985-01-01

    The contribution of molecular dissociative processes to the production of atomic lines is considered for a steady-state hydrogen plasma. If the contribution of dissociative processes is dominant, a substantial simplification in plasma diagnostics can be achieved. Numerical calculations have been performed for the production of Balmer alpha, beta, and gamma lines in hydrogen plasmas with medium and large degrees of ionization (x greater than about 0.0001) and for electron temperatures of 5000-45,000 K and electron densities of 10 to the 10th to 10 to the 16th/cu cm.

  17. Magnetic structure in cool stars. XVI - Emissions from the outer atmosphere of M-type dwarfs

    NASA Technical Reports Server (NTRS)

    Rutten, R. G. M.; Zwaan, C.; Schrijver, C. J.; Duncan, D. K.; Mewe, R.

    1989-01-01

    Consideration is given to emission from the outer atmospheres of M-type dwarfs in several spectral lines originating from the chromosphere, the transition-region, and the soft X-ray emission from the corona. It is shown that M-type dwarfs systematically deviate from relations between flux densities in soft X-rays and chromospheric and transition-region emission lines. The quantitative relation between the equivalent width of H-alpha and the Ca II, H, and K emission index is determined. It is suggested that the emission in the Balmer spectrum may result from back heating by coronal soft X-rays.

  18. Development of a multichannel Fourier-transform spectrometer to measure weak chemiluminescence: Application to the emission of singlet-oxygen dimol in the decomposition of hydrogen peroxide with gallic acid and K 3[Fe(CN) 6

    NASA Astrophysics Data System (ADS)

    Tsukino, Kazuo; Satoh, Toshihiro; Ishii, Hiroshi; Nakata, Munetaka

    2008-05-01

    A Fourier-transform spectrometer equipped with a Savart-plate polarization interferometer was developed for observation of weak chemiluminescence and applied to a measurement of emission spectra in the decomposition of hydrogen peroxide with gallic acid and K 3[Fe(CN) 6]. The band appearing at ˜580 nm in the chemiluminescence spectrum was assigned to the emission of singlet-oxygen dimol, the peak wavelength being shifted from that observed in the reaction of hydrogen peroxide with sodium hypochlorite, ˜633 nm. The band intensity was increased with the increasing concentration of K 3[Fe(CN) 6] up to ˜100 mM, and thereafter the peak wavelength was shifted from 580 to 700 nm with a decrease in the intensity.

  19. 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

  20. PHYSICAL PROPERTIES, STAR FORMATION, AND ACTIVE GALACTIC NUCLEUS ACTIVITY IN BALMER BREAK GALAXIES AT 0 < z < 1

    SciTech Connect

    Diaz Tello, J.; Donzelli, C.; Padilla, N.; Fujishiro, N.; Yoshikawa, T.; Hanami, H.; Hatsukade, B.

    2013-07-01

    We present a spectroscopic study with the derivation of the physical properties of 37 Balmer break galaxies, which have the necessary lines to locate them in star-forming-active galactic nuclei (AGNs) diagnostic diagrams. These galaxies span a redshift range from 0.045 to 0.93 and are somewhat less massive than similar samples of previous works. The studied sample has multiwavelength photometric data coverage from the ultraviolet to mid-infrared (MIR) Spitzer bands. We investigate the connection between star formation and AGN activity via optical, mass-excitation (MEx), and MIR diagnostic diagrams. Through optical diagrams, 31 (84%) star-forming galaxies, two (5%) composite galaxies, and three (8%) AGNs were classified, whereas from the MEx diagram only one galaxy was classified as AGN. A total of 19 galaxies have photometry available in all the IRAC/Spitzer bands. Of these, three AGN candidates were not classified as AGN in the optical diagrams, suggesting they are dusty/obscured AGNs, or that nuclear star formation has diluted their contributions. By fitting the spectral energy distribution of the galaxies, we derived the stellar masses, dust reddening E(B - V), ages, and UV star formation rates (SFRs). Furthermore, the relationship between SFR surface density ({Sigma}{sub SFR}) and stellar mass surface density per time unit ({Sigma}{sub M{sub */{tau}}}) as a function of redshift was investigated using the [O II] {lambda}3727, 3729, H{alpha} {lambda}6563 luminosities, which revealed that both quantities are larger for higher redshift galaxies. We also studied the SFR and specific SFR (SSFR) versus stellar mass and color relations, with the more massive galaxies having higher SFR values but lower SSFR values than less massive galaxies. These results are consistent with previous ones showing that, at a given mass, high-redshift galaxies have on average larger SFR and SSFR values than low-redshift galaxies. Finally, bluer galaxies have larger SSFR values than redder

  1. 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.

  2. Hydrogen production

    NASA Technical Reports Server (NTRS)

    England, C.; Chirivella, J. E.; Fujita, T.; Jeffe, R. E.; Lawson, D.; Manvi, R.

    1975-01-01

    The state of hydrogen production technology is evaluated. Specific areas discussed include: hydrogen production fossil fuels; coal gasification processes; electrolysis of water; thermochemical production of hydrogen; production of hydrogen by solar energy; and biological production of hydrogen. Supply options are considered along with costs of hydrogen production.

  3. Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

    PubMed Central

    Parigger, Christian G.; Woods, Alexander C.; Witte, Michael J.; Swafford, Lauren D.; Surmick, David M.

    2014-01-01

    In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 µm spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO). The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS. PMID:24561875

  4. DUST EXTINCTION FROM BALMER DECREMENTS OF STAR-FORMING GALAXIES AT 0.75 {<=} z {<=} 1.5 WITH HUBBLE SPACE TELESCOPE/WIDE-FIELD-CAMERA 3 SPECTROSCOPY FROM THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY

    SciTech Connect

    Dominguez, A.; Siana, B.; Masters, D.; Henry, A. L.; Martin, C. L.; Scarlata, C.; Bedregal, A. G.; Malkan, M.; Ross, N. R.; Atek, H.; Colbert, J. W.; Teplitz, H. I.; Rafelski, M.; McCarthy, P.; Hathi, N. P.; Dressler, A.; Bunker, A.

    2013-02-15

    Spectroscopic observations of H{alpha} and H{beta} emission lines of 128 star-forming galaxies in the redshift range 0.75 {<=} z {<=} 1.5 are presented. These data were taken with slitless spectroscopy using the G102 and G141 grisms of the Wide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of the WFC3 Infrared Spectroscopic Parallel survey. Interstellar dust extinction is measured from stacked spectra that cover the Balmer decrement (H{alpha}/H{beta}). We present dust extinction as a function of H{alpha} luminosity (down to 3 Multiplication-Sign 10{sup 41} erg s{sup -1}), galaxy stellar mass (reaching 4 Multiplication-Sign 10{sup 8} M {sub Sun }), and rest-frame H{alpha} equivalent width. The faintest galaxies are two times fainter in H{alpha} luminosity than galaxies previously studied at z {approx} 1.5. An evolution is observed where galaxies of the same H{alpha} luminosity have lower extinction at higher redshifts, whereas no evolution is found within our error bars with stellar mass. The lower H{alpha} luminosity galaxies in our sample are found to be consistent with no dust extinction. We find an anti-correlation of the [O III] {lambda}5007/H{alpha} flux ratio as a function of luminosity where galaxies with L {sub H{alpha}} < 5 Multiplication-Sign 10{sup 41} erg s{sup -1} are brighter in [O III] {lambda}5007 than H{alpha}. This trend is evident even after extinction correction, suggesting that the increased [O III] {lambda}5007/H{alpha} ratio in low-luminosity galaxies is likely due to lower metallicity and/or higher ionization parameters.

  5. Modeling of neutrals in the Linac4 H(-) ion source plasma: hydrogen atom production density profile and Hα intensity by collisional radiative model.

    PubMed

    Yamamoto, T; Shibata, T; Ohta, M; Yasumoto, M; Nishida, K; Hatayama, A; Mattei, S; Lettry, J; Sawada, K; Fantz, U

    2014-02-01

    To control the H(0) atom production profile in the H(-) ion sources is one of the important issues for the efficient and uniform surface H(-) production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H(0) atoms from H2 molecules in the model geometry of the radio-frequency (RF) H(-) ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H(0) production and the Balmer Hα photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H(-) ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established. PMID:24593558

  6. MAPPING DUST THROUGH EMISSION AND ABSORPTION IN NEARBY GALAXIES

    SciTech Connect

    Kreckel, Kathryn; Groves, Brent; Schinnerer, Eva; Meidt, Sharon E.; Tabatabaei, Fatemeh S.; Johnson, Benjamin D.; Aniano, Gonzalo; Calzetti, Daniela; Croxall, Kevin V.; Draine, Bruce T.; Gordon, Karl D.; Crocker, Alison F.; Smith, J. D. T.; Dale, Daniel A.; Hunt, Leslie K.; Kennicutt, Robert C.

    2013-07-01

    Dust has long been identified as a barrier to measuring inherent galaxy properties. However, the link between dust and attenuation is not straightforward and depends on both the amount of dust and its distribution. Herschel imaging of nearby galaxies undertaken as part of the KINGFISH project allows us to map the dust as seen in emission with unprecedented sensitivity and {approx}1 kpc resolution. We present here new optical integral field unit spectroscopy for eight of these galaxies that provides complementary 100-200 pc scale maps of the dust attenuation through observation of the reddening in both the Balmer decrement and the stellar continuum. The stellar continuum reddening, which is systematically less than that observed in the Balmer decrement, shows no clear correlation with the dust, suggesting that the distribution of stellar reddening acts as a poor tracer of the overall dust content. The brightest H II regions are observed to be preferentially located in dusty regions, and we do find a correlation between the Balmer line reddening and the dust mass surface density for which we provide an empirical relation. Some of the high-inclination systems in our sample exhibit high extinction, but we also find evidence that unresolved variations in the dust distribution on scales smaller than 500 pc may contribute to the scatter in this relation. We caution against the use of integrated A{sub V} measures to infer global dust properties.

  7. Non-LTE Line Formation for Hydrogen Revisited

    NASA Astrophysics Data System (ADS)

    Przybilla, Norbert; Butler, Keith

    2004-07-01

    We discuss aspects of non-LTE line formation for hydrogen in early-type stars. We evaluate the effect of variations in the electron-impact excitation cross sections in model atoms of differing complexity by comparison with observation. While the Balmer lines are basically unaffected by the choice of atomic data, the Paschen, Brackett, and Pfund series members allow us to discriminate between the different models. Non-LTE calculations based on the widely used approximation formulae of Mihalas, Heasley, & Auer and of Johnson fail to simultaneously reproduce the optical and IR spectra over the entire parameter range. The use of data from ab initio calculations up to principal quantum number n<=7 largely solves the problem. We recommend a reference model using the available data. This model is of general interest because of the ubiquity of the hydrogen spectrum.

  8. Spatial Correlation between Dust and Hα Emission in Dwarf Irregular Galaxies

    NASA Astrophysics Data System (ADS)

    Jimmy; Tran, Kim-Vy; Saintonge, Amélie; Accurso, Gioacchino; Brough, Sarah; Oliva-Altamirano, Paola; Salmon, Brett; Forrest, Ben

    2016-07-01

    Using a sample of dwarf irregular galaxies selected from the ALFALFA blind H i-survey and observed using the VIMOS IFU, we investigate the relationship between Hα emission and Balmer optical depth ({τ }{{b}}). We find a positive correlation between Hα luminosity surface density and Balmer optical depth in 8 of 11 at ≥0.8σ significance (6 of 11 at ≥1.0σ) galaxies. Our spaxels have physical scales ranging from 30 to 80 pc, demonstrating that the correlation between these two variables continues to hold down to spatial scales as low as 30 pc. Using the Spearman’s rank correlation coefficient to test for correlation between {{{Σ }}}{{H}α } and {τ }{{b}} in all the galaxies combined, we find ρ =0.39, indicating a positive correlation at 4σ significance. Our low stellar-mass galaxy results are in agreement with observations of emission line regions in larger spiral galaxies, indicating that this relationship is independent of the size of the galaxy hosting the emission line region. The positive correlation between Hα luminosity and Balmer optical depth within spaxels is consistent with the hypothesis that young star-forming regions are surrounded by dusty birth-clouds. Based on VLT service mode observations (Programs 081.B-0649 and 083.B-0662) gathered at the European Southern Observatory, Chile.

  9. The First Reported Infrared Emission from the SN1006 Remnant

    NASA Technical Reports Server (NTRS)

    Winkler, P. Frank; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Ghavamian, Parviz; Long, Knox S.; Raymond, John C.; Reynolds, Stephen P.

    2012-01-01

    We report results of infrared imaging and spectroscopic observations of the SN 1006 remnant, carried out with the Spitzer Space Telescope. The 24 m image from MIPS clearly shows faint filamentary emission along the northwest rim of the remnant shell, nearly coincident with the Balmer filaments that delineate the present position of the expanding shock. The 24 m emission traces the Balmer filaments almost perfectly, but lies a few arcsec within, indicating an origin in interstellar dust heated by the shock. Subsequent decline in the IR behind the shock is presumably due largely to grain destruction through sputtering. The emission drops far more rapidly than current models predict, however, even for a higher proportion of small grains than would be found closer to the Galactic plane. The rapid drop may result in part from a grain density that has always been lowera relic effect from an earlier epoch when the shock was encountering a lower densitybut higher grain destruction rates still seem to be required. Spectra from three positions along the NW filament from the IRS instrument all show only a featureless continuum, consistent with thermal emission from warm dust. The dust-to-gas mass ratio in the pre-shock interstellar medium is lower than that expected for the Galactic ISM-as has also been observed in the analysis of IR emission from other SNRs but whose cause remains unclear. As with other SNIa remnants, SN1006 shows no evidence for dust grain formation in the supernova ejecta.

  10. Hydrogenation apparatus

    DOEpatents

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

    1981-01-01

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

  11. A high-resolution field-emission-gun, scanning electron microscope investigation of anisotropic hydrogen decrepitation in Nd-Fe-B-based sintered magnets

    SciTech Connect

    Soderznik, Marko; McGuiness, Paul; Zuzek-Rozman, Kristina; Kobe, Spomenka; Skulj, Irena; Yan Gaolin

    2010-05-15

    In this investigation commercial magnets based on (Nd,Dy){sub 14}(Fe,Co){sub 79}B{sub 7} were prepared by a conventional powder-metallurgy route with a degree of alignment equal to {approx}90% and then exposed to hydrogen at a pressure of 1 bar. The magnets, in the form of cylinders, were observed to decrepitate exclusively from the ends. High-resolution electron microscopy was able to identify the presence of crack formation within the Nd{sub 2}Fe{sub 14}B grains, with the cracks running parallel to the c axis of these grains. Based on the concentration profile for hydrogen in a rare-earth transition-metal material, it is clear that the presence of hydrogen-induced cracks running perpendicular to the ends of the magnet provides for a much more rapidly progressing hydrogen front in this direction than from the sides of the magnet. This results in the magnet exhibiting a macroscopic tendency to decrepitate from the poles of the magnet toward the center. This combination of microstructural modification via particle alignment as part of the sintering process and direct observation via high-resolution electron microscopy has led to a satisfying explanation for the anisotropic hydrogen-decrepitation effect.

  12. Multiple diagnostics in a high-pressure hydrogen microwave plasma torch

    SciTech Connect

    Torres, J.; Mullen, J. J. A. M. van der; Gamero, A.; Sola, A.

    2010-02-01

    We present an experimental study of a hydrogen plasma produced by a microwave axial injection torch, launching the plasma in a helium-filled chamber. Three different diagnostic methods have been used to obtain the electron density and temperature as follows: The Stark intersection method of Balmer spectral lines (already tested in argon and helium plasmas); the modified Boltzmann-plot showing that the plasma is far from the local thermodynamic equilibrium but ruled by the excitation-saturation balance; and a study by the disturbed bilateral relations theory. All of these diagnostic techniques show a good agreement.

  13. 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.

  14. 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

  15. High-frequency variations of hydrogen spectral lines in the B3V star η UMa

    NASA Astrophysics Data System (ADS)

    Pokhvala, S. M.

    2015-09-01

    We reported the detection of high-frequency variations in the hydrogen Balmer lines in the hot star η UMa of spectral class B3V. Spectral observations of η UMa were carried out with slitless spectrograph (R˜100) installed on the 60 cm Carl Zeiss telescope in the Andrushivka Observatory. Spectra were obtained with a time resolution in the sub-second range. It has been found that the η UMa shows rapid variations in the hydrogen lines Hα, Hβ, Hγ, as well as variations in the atmospheric oxygen lines. The intensity variations in the hydrogen lines varies from 0.2% to 0.5% , and that of the oxygen lines is approximately 2%.

  16. NLTE in a Hot Hydrogen Star: Auer & Mihalas Revisited

    NASA Astrophysics Data System (ADS)

    Wiersma, J.; Rutten, R. J.; Lanz, T.

    2003-01-01

    We pay tribute to two landmark papers published by Auer & Mihalas in 1969. They modeled hot-star NLTE-RE hydrogen-only atmospheres, using two simplified hydrogen atoms: ApJ 156, 157: H I levels 1, 2 and c, Lyman α the only line ApJ 156, 681: H I levels 1, 2, 3 and c, Balmer α the only line and computed LTE and NLTE models with the single line turned on and off. The results were extensively analyzed in the two papers. Any student of stellar line formation should take these beautiful papers to heart. The final exercise in Rutten's lecture notes ``Radiative Transfer in Stellar Atmospheres'' asks the student to work through five pages of questions concerning diagrams from the first paper alone! That exercise led to the present work in which we recompute the Auer-Mihalas hot-hydrogen-star models with TLUSTY, adding results from a complete hydrogen atom for comparison. Our motivation for this Auer-Mihalas re-visitation is twofold: 1. to add diagnostic diagrams to the ones published by Auer & Mihalas, in particular Bν, Jν, Sν graphs to illustrate the role of the radiation field, and radiative heating & cooling graphs to illustrate the radiative energy budget, 2. to see the effect of adding the rest of the hydrogen atom.

  17. Two-photon decay of excited levels in hydrogen: The ambiguity of the separation of cascades and pure two-photon emission

    NASA Astrophysics Data System (ADS)

    Labzowsky, L.; Solovyev, D.; Plunien, G.

    2009-12-01

    The problem of the evaluation of the two-photon decay width of excited states in hydrogen is considered. Two different approaches to the evaluation of the width including cascades channels are employed: the summation of the transition probabilities for various decay channels and the evaluation of the imaginary part of the Lamb shift. As application, the two-photon decay channels for the 3s level of the hydrogen atom are evaluated, including the cascade transition probability 3s-2p-1s . An important role is assigned to the two-photon decays in astrophysics context, since processes of this kind provide a possibility for the decoupling of radiation and matter in the early universe. We demonstrate the ambiguity of separation of the “pure” two-photon contribution and criticize the existing methods for such a separation.

  18. 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.

  19. Hydrogen added after-burner system

    SciTech Connect

    Kanada, Youji; Hayasi, Masaharu; Akaki, Motonobu; Tsuchikawa, Shunzou; Isomura, Akihito

    1996-09-01

    The authors developed a hydrogen-added afterburner system for a new catalyst heating system, which realized large reduction of emissions during start-up at low temperatures when hydrocarbon (HC) emission was rather high. Key development items of this system are a water electrolysis type small size on-board hydrogen supply unit and an engine matching technique for the verification of emission reduction effects.

  20. 40 CFR 98.163 - Calculating GHG emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.163 Calculating GHG emissions. You must calculate and report the annual process CO2 emissions from each hydrogen production process unit... emissions associated with each fuel and feedstock used for hydrogen production by following paragraphs...

  1. Hydrogenation apparatus

    DOEpatents

    Friedman, J.; Oberg, C. L.; Russell, L. H.

    1981-06-23

    Hydrogenation reaction apparatus is described comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1,100 to 1,900 C, while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products. 2 figs.

  2. Distribution of Atomic Hydrogen in the Upper Atmosphere: Assessment of Absolute Densities and Variations in the light of Recent Observations

    NASA Astrophysics Data System (ADS)

    Bishop, J.

    2002-12-01

    Knowledge of atomic hydrogen densities ([H](z)) in the upper atmosphere is important both for understanding mesospheric-lower thermospheric (MLT) chemistry and for realistic modeling of geocoronal interactions with ionized populations (e.g., plasmasphere, ring current). Work culminating in the 1970's failed to achieve consistent determinations of the distribution of atomic hydrogen; because of this, the relevance of [H](z) determinations in other areas of aeronomic research has remained unacknowledged. Extensive independent sets of optical data, coupled with improved solar Lyman line series irradiances and corrections of assumptions used in the earlier data analyses, however, now enable us to resolve the older inconsistencies and pursue determination of quantities of genuine interest: thermospheric atomic hydrogen vertical fluxes, characteristics of the satellite atom component in the geocorona, etc. These data sets include: Wisconsin Hα\\ Mapper (WHAM) Fabry-Perot data from Kitt Peak Observatory, providing ~ \\ 40,000\\ spectra of geocoronal and galactic Balmer~α intensities beginning in 1997; very high resolution Fabry-Perot data from Pine Bluff Observatory (Wisconsin) of both Balmer~α\\ and Balmer~β\\ intensities and line profiles from 2000-2001; FUSE EUV measurements of Lyman line series intensities from 1999 and 2000 (excluding Lyman~α); MiniSat1/EURD EUV spectrometer measurements of Lyman line series intensities (excluding Lyman~α) from 1997 to 2001; and IMAGE/GEO Lyman~α\\ intensity data from geocoronal positions (satellite apogees ~ 7~R E). In this presentation, modeling analyses of representative data subsets will be discussed, focusing on results relevant to broader aeronomy topics.

  3. Emissions and concentrations of hydrogen sulfide in the air of the tropical forest of the Ivory Coast and of temperate regions in France

    SciTech Connect

    Delmas, R.; Baudet, J.; Servant, J.; Baziard, Y.

    1980-08-20

    Atmospheric H/sub 2/S was measured by a fluorometric method (sensitivity 10 ng). In France, for aerated soils the emissions were between 0.8 and 27 ..mu..g m/sup -2/ h/sup -1/ H/sub 2/S (average 5 ..mu..g m/sup -2/ h/sup -1/). The soil temperature is an important factor governing this emission. The H/sub 2/S concentrations in the air ranged from 0.017 to 0.17 ..mu..g m/sup -3/ (average 0.080 ..mu..g m/sup -3/). In the Ivory Coast the H/sub 2/S emissions were estimated between 30 and 300 ..mu..g m/sup -2/ h/sup -1/. The measured concentrations of H/sub 2/S in the air at ground level ranged from 0.10 to 8.7 ..mu..g m/sup -3/. The relative importance of the measured emissions for anoxic soils of the humid equatorial forests in the global S cycle is discussed.

  4. Emissions of greenhouse gases, ammonia, and hydrogen sulfide from pigs fed standard diets and diets supplemented with dried distillers grains with solubles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine growers are increasingly supplementing animal diets with dried distillers grains soluble (DDGS) to offset cost of a typical corn-soybean meal diet. An experiment was conducted to investigate the effects of DDGS diets on both on manure composition and emissions of greenhouse gases (GHG), ammoni...

  5. Line shape modeling in warm and dense hydrogen plasmas

    NASA Astrophysics Data System (ADS)

    Ferri, S.; Calisti, A.; Mossé, C.; Talin, B.; Gigosos, M. A.; González, M. A.

    2007-05-01

    A study of hydrogen lines emitted in warm ( T˜1eV) and dense ( N≥1018cm -3) plasmas is presented. Under such plasma conditions, the electronic and the ionic contributions to the line width are comparable, and the general question related to a transition from impact to quasi-static broadening arises not only for the far wings but also for the core of spectral lines. The transition from impact to quasi-static broadening for electrons is analyzed by means of Frequency Fluctuation Model (FFM). In parallel, direct integration of the semi-classical evolution equation is performed using electron electric fields calculated by Molecular Dynamics (MD) simulations that permit one to correctly describe the emitter environment. New cross comparisons between benchmark MD simulations and FFM are carried out for electron broadening of the Balmer series lines, and, especially, for the Hα line, for which a few experiments in the warm and dense plasma regimes are available.

  6. The distribution of hydrogen, nitrogen, and chlorine radicals in the lower stratosphere: Implications for changes in O3 due to emission of NO(y) from supersonic aircraft

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; We-Nnberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.

    1994-01-01

    In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower statosphere during SPADE are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N2O5 agree well with measured concentrations of NO and ClO, but concentrations of HO2 and OH are underestimated by 10 to 25%, concentrations of NO2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for (OH) and (HO2) are reduced if we allow for higher yields of O((1)D) from O2 photolysis and for heterogeneous production of HNO2. The data suggest more efficent catalytic removal of O3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommendend rates and cross sections. Increased in (O3) in the lower stratosphere may be larger in response to inputs of NO(y) from supersonic aircraft than estimated by current assessment models.

  7. The Distribution of Hydrogen, Nitrogen, and Chlorine Radicals in the Lower Stratosphere: Implications for Changes in O3 due to Emission of NO(y) from Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.; Koplow, P.; Kohn, D. W.; Webster, C. R.; May, R. D.; Pfister, L.; Gottlieb, E. W.; Michelsen, H. A.; Yue, G. K.; Wilson, J. C.; Brock, C. A.

    1994-01-01

    In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower stratosphere during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N2O5 agree well with measured concentrations of NO and ClO, but concentrations of HO2 and OH are underestimated by 10 to 25%, concentrations of NO2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for [OH] and [HO2] are reduced if we allow for higher yields of O(sup 1)D) from 03 photolysis and for heterogeneous production of HNO2. The data suggest more efficient catalytic removal of O3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommended rates and cross sections. Increases in [O3] in the lower stratosphere may be larger in response to inputs of NO(sub y) from supersonic aircraft than estimated by current assessment models.

  8. Hydrogenated Polycyclic Aromatic Hydrocarbons and the 2940 and 2850 Wavenumber (3.40 and 3.51 micron) Infrared Emission Features

    NASA Technical Reports Server (NTRS)

    Bernstein, Max P.; Sandford, Scott A.; Allamadola, Louis J.

    1996-01-01

    The 3150-2700/cm (3.17-3.70 micron) range of the spectra of a number of Ar-matrix-isolated PAHs containing excess H atoms (H(sub n)-PAHS) are presented. This region covers features produced by aromatic and aliphatic C-H stretching vibrations as well as overtone and combination bands involving lower lying fundamentals. The aliphatic C-H stretches in molecules of this type having low to modest excess H coverage provide excellent fits to a number of the weak emission features superposed on the plateau between 3080 and 2700/cm (3.25 and 3.7 micron) in the spectra of many planetary nebulae, reflection nebulae, and H II regions. Higher H coverage is implied for a few objects. We compare these results in context with the other suggested identifications of the emission features in the 2950-2700/cm (3.39-3.70 micron) region and briefly discuss their astrophysical implications.

  9. Far-Red Emission of mPlum Fluorescent Protein Results from Excited-State Interconversion between Chromophore Hydrogen-Bonding States.

    PubMed

    Yoon, Eunjin; Konold, Patrick E; Lee, Junghwa; Joo, Taiha; Jimenez, Ralph

    2016-06-16

    Fluorescent proteins with large Stokes shifted emission beyond 600 nm are actively sought for live-cell imaging applications. The mechanism of excited-state relaxation leading to the Stokes shift in the mPlum fluorescent protein, which emits at a peak wavelength of 650 nm, has been previously investigated by both ultrafast spectroscopy and theoretical methods. Here, we report that femtosecond time-resolved area-normalized emission spectra of mPlum show a clear isoemissive point. This feature can only result from a system with two emitting states, rather than a system that undergoes a continuous spectral red shift, for example, as expected from typical solvation. Global analysis of the femtosecond time-resolved fluorescence spectra reveals time constants associated with chromophore relaxation, excited-state population transfer, and an excited-state lifetime of the final state. The observations confirm the findings of recent quantum chemical calculations on mPlum. PMID:27214167

  10. Emissions of the natural acidic substance in the acid rain region: Dimethyl sulfide and hydrogen sulfide in the region of Xiamen, China

    SciTech Connect

    Yubao Wang; Miaoqin Lu

    1996-12-31

    The global anthropogenic emissions of sulfur, mainly SO2, are relatively well studied for most of the industrialized world, and relatively little is known to date about natural sulfur emission sources, such as, coastal waters and wetland. The most important atmospheric sulfur compounds originating from biogeochemical sources are DMS and H{sub 2}S. Previous studies suggest that biogenic DMS is mainly emitted from oceanic phytoplankton species. The global emission of sulfur by this process was estimated to be 40 Tg S/year. Major sources of biogenic H{sub 2}S in the atmosphere are believed to be bacterial sulfate reduction in anoxic soils and degradation of organic matter. The mentioned reduced sulfur compounds are partially oxidation in the troposphere to SO{sub 2} and further to sulfur acid, another strong acid produced from DMS oxidation is methane sulphonic acid (CH{sub 3}S(O{sub 2})OH). These compounds are strong acid and will influence the pH of precipitation and will be the important impact in acid rain phenomena.

  11. 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

  12. Hydrogen Generator

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Another spinoff from spacecraft fuel cell technology is the portable hydrogen generator shown. Developed by General Electric Company, it is an aid to safer operation of systems that use hydrogen-for example, gas chromatographs, used in laboratory analysis of gases. or flame ionization detectors used as $ollution monitors. The generator eliminates the need for high-pressure hydrogen storage bottles, which can be a safety hazard, in laboratories, hospitals and industrial plants. The unit supplies high-purity hydrogen by means of an electrochemical process which separates the hydrogen and oxygen in distilled water. The oxygen is vented away and the hydrogen gas is stored within the unit for use as needed. GE's Aircraft Equipment Division is producing about 1,000 of the generators annually.

  13. Hydrogen and OUr Energy Future

    SciTech Connect

    Rick Tidball; Stu Knoke

    2009-03-01

    In 2003, President George W. Bush announced the Hydrogen Fuel Initiative to accelerate the research and development of hydrogen, fuel cell, and infrastructure technologies that would enable hydrogen fuel cell vehicles to reach the commercial market in the 2020 timeframe. The widespread use of hydrogen can reduce our dependence on imported oil and benefit the environment by reducing greenhouse gas emissions and criteria pollutant emissions that affect our air quality. The Energy Policy Act of 2005, passed by Congress and signed into law by President Bush on August 8, 2005, reinforces Federal government support for hydrogen and fuel cell technologies. Title VIII, also called the 'Spark M. Matsunaga Hydrogen Act of 2005' authorizes more than $3.2 billion for hydrogen and fuel cell activities intended to enable the commercial introduction of hydrogen fuel cell vehicles by 2020, consistent with the Hydrogen Fuel Initiative. Numerous other titles in the Act call for related tax and market incentives, new studies, collaboration with alternative fuels and renewable energy programs, and broadened demonstrations--clearly demonstrating the strong support among members of Congress for the development and use of hydrogen fuel cell technologies. In 2006, the President announced the Advanced Energy Initiative (AEI) to accelerate research on technologies with the potential to reduce near-term oil use in the transportation sector--batteries for hybrid vehicles and cellulosic ethanol--and advance activities under the Hydrogen Fuel Initiative. The AEI also supports research to reduce the cost of electricity production technologies in the stationary sector such as clean coal, nuclear energy, solar photovoltaics, and wind energy.

  14. Hydrogen-enrichment-concept preliminary evaluation

    NASA Technical Reports Server (NTRS)

    Ecklund, E. E.

    1975-01-01

    A hydrogen-enriched fuels concept for automobiles is described and evaluated in terms of fuel consumption and engine exhaust emissions through multicylinder (V-8) automotive engine/hydrogen generator tests, single cylinder research engine (CFR) tests, and hydrogen-generator characterization tests. Analytical predictions are made of the fuel consumption and NO/sub x/ emissions which would result from anticipated engine improvements. The hydrogen-gas generator, which was tested to quantify its thermodynamic input-output relationships was used for integrated testing of the V-8 engine and generator.

  15. Hydrogen Production Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The Hydrogen Production Technical Team Roadmap identifies research pathways leading to hydrogen production technologies that produce near-zero net greenhouse gas (GHG) emissions from highly efficient and diverse renewable energy sources. This roadmap focuses on initial development of the technologies, identifies their gaps and barriers, and describes activities by various U.S. Department of Energy (DOE) offices to address the key issues and challenges.

  16. Time variations of UV emission features of Be stars

    NASA Technical Reports Server (NTRS)

    Bahng, J. D. R.

    1975-01-01

    The UV spectra of three Be stars (gamma Cas, sigma Tau, eta Cen) were studied. Of the six Be stars observed in the first four lines of the Balmer series, three stars showed at least one of the Balmer lines to be variable in the equivalent width amounting to a few percent with time scales of 3 to 30 minutes. Photoelectric spectrum scans of five southern Wolf-Rayet stars showed night-to-night variations. A simple model is proposed to account for the behavior of these emission lines. Scans of gamma square Vel showed rapid variations of emission strengths of He II 4686 and C III - IV 4650. These variations have time scales of 1 minute and longer. Night-to-night variations were also found. Scans of four Be stars in H alpha showed a definite variation of 3 to 4 percent, with time scales of 1 minute and longer in sigma Tau. In 48 Per and kappa Dra the variations are not as well established. No variation of any significance was found for nu Gem.

  17. STRONG RESPONSE OF THE VERY BROAD H{beta} EMISSION LINE IN THE LUMINOUS RADIO-QUIET QUASAR PG 1416-129

    SciTech Connect

    Wang, J.; Li, Y.

    2011-11-20

    We report new spectroscopic observations performed in 2010 and 2011 for the luminous radio-quiet quasar PG 1416-129. Our new spectra with high quality cover both H{beta} and H{alpha} regions, and show negligible line profile variation within a timescale of one year. The two spectra allow us to study the variability of the Balmer line profile by comparing the spectra with previous ones taken at 10 and 20 years ago. By decomposing the broad Balmer emission lines into two Gaussian profiles, our spectral analysis suggests a strong response to the continuum level for the very broad component, and significant variations in both bulk blueshift velocity/FWHM and flux for the broad component. The new observations additionally indicate flat Balmer decrements (i.e., too strong H{beta} emission) at the line wings, which is hard to reproduce using recent optically thin models. With these observations we argue that a separate inner optically thin emission-line region might not be necessary in the object to reproduce the observed line profiles.

  18. Spectra, Emission Yields, Cross Sections, and Kinetic Energy Distributions of Hydrogen Atoms from H2 X 1Eg+-d 3IIu Excitation by Electron Impact

    NASA Astrophysics Data System (ADS)

    Liu, Xianming; Shemansky, Donald E.; Yoshii, Jean; Johnson, Paul V.; Malone, Charles P.; Ajello, Joseph M.

    2016-02-01

    Electron-impact excitation of H2 triplet states plays an important role in the heating of outer planet upper thermospheres. The {d}3{{{\\Pi }}}u state is the third ungerade triplet state, and the {d}3{{{\\Pi }}}u-a{}3{{{Σ }}}g+ emission is the largest cascade channel for the a{}3{{{Σ }}}g+ state. Accurate energies of the d{}3{{{\\Pi }}}u-(v, J) levels are calculated from an ab initio potential energy curve. Radiative lifetimes of the {d}3{{{\\Pi }}}u(v, J) levels are obtained by an accurate evaluation of the {d}3{{{\\Pi }}}u-a{}3{{{Σ }}}g+ transition probabilities. The emission yields are determined from experimental lifetimes and calculated radiative lifetimes and are further verified by comparing experimental and synthetic {d}3{{{\\Pi }}}u-a{}3{{{Σ }}}g+ spectra at 20 eV impact energy. Spectral analysis revealed that multipolar components beyond the dipolar term are required to model the {X}1{{{Σ }}}g+-{d}3{{{\\Pi }}}u excitation, and significant cascade excitation occurs at the {d}3{{{\\Pi }}}u(v = 0,1) levels. Kinetic energy (Ek) distributions of H atoms produced via predissociation of the {d}3{{{\\Pi }}}u state and the {d}3{{{\\Pi }}}u-a{}3{{{Σ }}}g+-b{}3{{{Σ }}}u+ cascade dissociative emission are obtained. Predissociation of the {d}3{{{\\Pi }}}u state produces H atoms with an average Ek of 2.3 ± 0.4 eV/atom, while the Ek distribution of the {d}3{{{\\Pi }}}u-a{}3{{{Σ }}}g+-b{}3{{{Σ }}}u+ channel is similar to that of the {X}1{{{Σ }}}g+-a{}3{{{Σ }}}g+-b{}3{{{Σ }}}u+ channel and produces H(1s) atoms with an average Ek of 1.15 ± 0.05 eV/atom. On average, each H2 excited to the {d}3{{{\\Pi }}}u state in an H2-dominated atmosphere deposits 3.3 ± 0.4 eV into the atmosphere, while each H2 directly excited to the a{}3{{{Σ }}}g+ state gives 2.2-2.3 eV to the atmosphere. The spectral distribution of the calculated a{}3{{{Σ }}}g+ -b{}3{{{Σ }}}u+ continuum emission due to the {X}1{{{Σ }}}g+-{d}3{{{\\Pi }}}u excitation is significantly different from

  19. Releve et analyse spectroscopiques d'etoiles naines blanches brillantes et riches en hydrogene

    NASA Astrophysics Data System (ADS)

    Gianninas, Alexandros

    2011-04-01

    We present a spectroscopic survey and analysis of over 1300 bright (V ≤ 17.5), hydrogen-rich white dwarfs. High signal-to-noise ratio optical spectra were obtained and are then analyzed using our standard spectroscopic technique which compares the observed Balmer line profiles to synthetic spectra computed from the latest generation of model atmospheres. First, we present a detailed analysis 29 DAO white dwarfs using our new up-to-date model atmosphere grids in which we have included carbon, nitrogen, and oxygen at solar abundances. We demonstrate that the inclusion of these metals in the model atmospheres is essential in overcoming the Balmer-line problem, which manifests itself as an inability to fit all the Balmer lines simultaneously with consistent atmospheric parameters. We also identify 18 hot DA white dwarfs that also suffer from the Balmer-line problem. Far ultraviolet spectra from the FUSE archive are then examined to demonstrate that there exists a correlation between higher metallic abundances and instances of the Balmer-line problem. The implications of these findings for all hot, hydrogen-rich white dwarfs are discussed. Specifically, the possible evolutionary scenario for DAO white dwarfs is revised and post-EHB evolution need no longer be invoked to explain the evolution for the majority of the DAO stars. Finally, we discuss how the presence of metals might drive a weak stellar wind which in turn could explain the presence of helium in DAO white dwarfs. We then present the complete results from our survey, including the spectroscopic analysis of over 1200 DA white dwarfs. First we present the spectroscopic content of our sample which includes many misclassifications as well as several DAB, DAZ and magnetic white dwarfs. We then discuss the new model atmospheres we employ in our analysis. In addition, we use M dwarf templates to obtain better estimates of the atmospheric parameters for those white dwarfs which are in DA+dM binary systems. A handful

  20. 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.

  1. Solar hydrogen for urban trucks

    SciTech Connect

    Provenzano, J.: Scott, P.B.; Zweig, R.

    1997-12-31

    The Clean Air Now (CAN) Solar Hydrogen Project, located at Xerox Corp., El Segundo, California, includes solar photovoltaic powered hydrogen generation, compression, storage and end use. Three modified Ford Ranger trucks use the hydrogen fuel. The stand-alone electrolyzer and hydrogen dispensing system are solely powered by a photovoltaic array. A variable frequency DC-AC converter steps up the voltage to drive the 15 horsepower compressor motor. On site storage is available for up to 14,000 standard cubic feet (SCF) of solar hydrogen, and up to 80,000 SCF of commercial hydrogen. The project is 3 miles from Los Angeles International airport. The engine conversions are bored to 2.9 liter displacement and are supercharged. Performance is similar to that of the Ranger gasoline powered truck. Fuel is stored in carbon composite tanks (just behind the driver`s cab) at pressures up to 3600 psi. Truck range is 144 miles, given 3600 psi of hydrogen. The engine operates in lean burn mode, with nil CO and HC emissions. NO{sub x} emissions vary with load and rpm in the range from 10 to 100 ppm, yielding total emissions at a small fraction of the ULEV standard. Two trucks have been converted for the Xerox fleet, and one for the City of West Hollywood. A public outreach program, done in conjunction with the local public schools and the Department of Energy, introduces the local public to the advantages of hydrogen fuel technologies. The Clean Air Now program demonstrates that hydrogen powered fleet development is an appropriate, safe, and effective strategy for improvement of urban air quality, energy security and avoidance of global warming impact. Continued technology development and cost reduction promises to make such implementation market competitive.

  2. Hydrogenated polycyclic aromatic hydrocarbons and the 2940 and 2850 wavenumber (3.40 and 3.51 micron) infrared emission features.

    PubMed

    Bernstein, M P; Sandford, S A; Allamandola, L J

    1996-12-01

    The 3150-2700 cm-1 (3.17-3.70 microns) range of the spectra of a number of Ar-matrix-isolated PAHs containing excess H atoms (Hn-PAHs) are presented. This region covers features produced by aromatic and aliphatic C-H stretching vibrations as well as overtone and combination bands involving lower lying fundamentals. The aliphatic C-H stretches in molecules of this type having low to modest excess H coverage provide excellent fits to a number of the weak emission features superposed on the plateau between 3080 and 2700 cm-1 (3.25 and 3.7 microns) in the spectra of many planetary nebulae, reflection nebulae, and H II regions. Higher H coverage is implied for a few objects. We compare these results in context with the other suggested identifications of the emission features in the 2950-2700 cm-1 (3.39-3.70 microns) region and briefly discuss their astrophysical implications. PMID:11541245

  3. Hydrogen as a transportation fuel: Costs and benefits

    SciTech Connect

    Berry, G.D.

    1996-03-01

    Hydrogen fuel and vehicles are assessed and compared to other alternative fuels and vehicles. The cost, efficiency, and emissions of hydrogen storage, delivery, and use in hybrid-electric vehicles (HEVs) are estimated. Hydrogen made thermochemically from natural gas and electrolytically from a range of electricity mixes is examined. Hydrogen produced at central plants and delivered by truck is compared to hydrogen produced on-site at filling stations, fleet refueling centers, and residences. The impacts of hydrogen HEVs, fueled using these pathways, are compared to ultra-low emissions gasoline internal-combustion-engine vehicles (ICEVs), advanced battery-powered electric vehicles (BPEVs), and HEVs using gasoline or natural gas.

  4. 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.

  5. Novel Metallic Membranes for Hydrogen Separation

    SciTech Connect

    Dogan, Omer

    2011-02-27

    To reduce dependence on oil and emission of greenhouse gases, hydrogen is favored as an energy carrier for the near future. Hydrogen can be converted to electrical energy utilizing fuel cells and turbines. One way to produce hydrogen is to gasify coal which is abundant in the U.S. The coal gasification produces syngas from which hydrogen is then separated. Designing metallic alloys for hydrogen separation membranes which will work in a syngas environment poses significant challenges. In this presentation, a review of technical targets, metallic membrane development activities at NETL and challenges that are facing the development of new technologies will be given.

  6. Possibility of nonexistence of hot and superhot hydrogen atoms in electrical discharges

    SciTech Connect

    Loureiro, J.; Amorim, J.

    2010-09-15

    Recently, the existence of extremely energetic hydrogen atoms in electrical discharges has been proposed in the literature with large controversy, from the analysis of the anomalous broadening of hydrogen Balmer lines. In this paper, the velocity distribution of H atoms and the profiles of the emitting atom lines created by the exothermic reaction H{sub 2}{sup +}+H{sub 2}{yields}H{sub 3}{sup +}+H+{Delta}E are calculated, as a function of the internal energy defect {Delta}E. The shapes found for the non-Maxwell-Boltzmann distributions resulting in non-Gaussian line profiles raise serious arguments against the existence of hot and superhot H atoms as it has been proposed, at least with those temperatures.

  7. Interpreting the Hydrogen IR Lines Impact of Improved Electron Collision Data

    NASA Astrophysics Data System (ADS)

    Przybilla, Norbert; Butler, Keith

    We evaluate the effect of variations in the electron-impact excitation cross sections on the non-LTE line formation for hydrogen in early-type stars. While the Balmer lines are basically unaffected by the choice of atomic data, the Brackett and Pfund series members allow us to discriminate between the different models. Non-LTE calculations based on the widely-used approximations of Mihalas, Heasley & Auer and of Johnson fail to simultaneously reproduce the observed optical and IR spectra over the entire parameter range. Instead, we recommend a reference model using data from ab-initio calculations up to principal quantum number n≤7 for quantitative work. This model is of general interest due to the ubiquity of the hydrogen spectrum.

  8. Emission control system

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor); Chung, J. Landy (Inventor)

    2009-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

  9. Contribution of Solar Hydrogen Lyα Line Emission in Total Ionization Rate in Ionospheric D-region During the Maximum of Solar X-flare

    NASA Astrophysics Data System (ADS)

    Nina, A.; Čadež, V. M.; Bajčetić, J.

    2015-12-01

    The solar Lyα line emission can be considered as the dominant source of ionization processes in the ionospheric D-region at altitudes above 70 km during unperturbed conditions. However, large sudden impacts of radiation in some other energy domains can also significantly influence the ionization rate and, in this paper, we present a study on the contribution of Lyα radiation to the ionization rate when the ionosphere is disturbed by solar X-flares. We give relevant analytical expressions and make calculations and numerical simulations for the low ionosphere using data collected by the VLF receiver located in Serbia for the VLF radio signal emitted by the DHO transmitter in Germany.

  10. Florida Hydrogen Initiative

    SciTech Connect

    Block, David L

    2013-06-30

    at any facility engaged in transport, handling and use of hydrogen. Development of High Efficiency Low Cost Electrocatalysts for Hydrogen Production and PEM Fuel Cell Applications ? M. Rodgers, Florida Solar Energy Center The objective of this project was to decrease platinum usage in fuel cells by conducting experiments to improve catalyst activity while lowering platinum loading through pulse electrodeposition. Optimum values of several variables during electrodeposition were selected to achieve the highest electrode performance, which was related to catalyst morphology. Understanding Mechanical and Chemical Durability of Fuel Cell Membrane Electrode Assemblies ? D. Slattery, Florida Solar Energy Center The objective of this project was to increase the knowledge base of the degradation mechanisms for membranes used in proton exchange membrane fuel cells. The results show the addition of ceria (cerium oxide) has given durability improvements by reducing fluoride emissions by an order of magnitude during an accelerated durability test. Production of Low-Cost Hydrogen from Biowaste (HyBrTec?) ? R. Parker, SRT Group, Inc., Miami, FL This project developed a hydrogen bromide (HyBrTec?) process which produces hydrogen bromide from wet-cellulosic waste and co-produces carbon dioxide. Eelectrolysis dissociates hydrogen bromide producing recyclable bromine and hydrogen. A demonstration reactor and electrolysis vessel was designed, built and operated. Development of a Low-Cost and High-Efficiency 500 W Portable PEMFC System ? J. Zheng, Florida State University, H. Chen, Bing Energy, Inc. The objectives of this project were to develop a new catalyst structures comprised of highly conductive buckypaper and Pt catalyst nanoparticles coated on its surface and to demonstrate fuel cell efficiency improvement and durability and cell cost reductions in the buckypaper based electrodes. Development of an Interdisciplinary Hydrogen and Fuel Cell Technology Academic Program ? J

  11. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  12. The one-dimensional hydrogen atom revisited

    NASA Astrophysics Data System (ADS)

    Palma, G.; Raff, U.

    2006-09-01

    The one-dimensional Schrodinger hydrogen atom is an interesting mathematical and physical problem for the study of bound states, eigenfunctions, and quantum-degeneracy issues. This one-dimensional physical system has given rise to some intriguing controversy for more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier-transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found that the complete Balmer energy spectrum is obtained together with an odd-parity set of eigenfunctions. Closed-form solutions in both coordinate and momentum spaces were obtained. No twofold degeneracy was observed as predicted by the degeneracy theorem in one dimension, though it does not necessarily have to hold for potentials with singularities. No ground state with infinite energy exists since the corresponding eigenfunction does not satisfy the Schrodinger equation at the origin.

  13. ADVANCED EMISSIONS CONTROL DEVELOPMENT PROGRAM

    SciTech Connect

    G.A. Farthing

    2001-02-06

    The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPs, or air toxics) from coal-fired boilers. The project goal is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses), and wet flue gas desulfurization (WFGD) systems. Development work initially concentrated on the capture of trace metals, fine particulate, hydrogen chloride, and hydrogen fluoride. Recent work has focused almost exclusively on the control of mercury emissions.

  14. Advanced Emissions Control Development Program

    SciTech Connect

    G. A. Farthing; G. T. Amrhein; G. A. Kudlac; D. A. Yurchison; D. K. McDonald; M. G. Milobowski

    2001-03-31

    The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPs, or air toxics) from coal-fired boilers. This objective is being met by identifying ways to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (fabric filters), and wet flue gas desulfurization (wet FGD) systems. Development work initially concentrated on the capture of trace metals, hydrogen chloride, and hydrogen fluoride. Recent work has focused almost exclusively on the control of mercury emissions.

  15. Emission control system

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2008-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce NOx, SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of NOx, SOx and heavy metals, while isolating useful by-products streams of sulfuric acid and nitric acid as well as solids for the recovery of the heavy metals.

  16. Emission-line mapping of the dwarf nova IP Pegasi in outburst and quiescence

    SciTech Connect

    Marsh, T.R.; Horne, K. )

    1990-02-01

    Time-resolved spectroscopy covering half an orbit and one eclipse during an outburst of the dwarf nova IP Peg are presented and compared with quiescent data. The outburst spectra show strong Balmer and He II 4686 A emission lines that are atypical of outbursting dwarf novae. Double-peaked velocity profiles and rotational distortions during eclipse show that the lines arise primarily in a Keplerian accretional disk. The He II line profile is filled in between the two disk peaks by non-Keplerian emission from close to the white dwarf, possibly indicative of a compact outflowing wind or inflowing magnetic accretion column. During outburst, an accretion rate of roughly 10 to the 17th g/s is needed to acccount for the continuum emission of the disk. The associated boundary layer generates soft X-ray and Lyman continuum fluxes sufficient to photoionize the disk's He II and Balmer emission-line regions. The disk appears to shield the red star totally from the soft X-rays, and in the equatorial region, from the Lyman continuum. 46 refs.

  17. Ammonia and hydrogen sulfide removal using biochar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  18. Hydrogen effects on material behavior; Proceedings of the 4th International Conference on the Effect of Hydrogen on the Behavior of Materials, Moran, WY, Sept. 12-15, 1989

    SciTech Connect

    Moody, N.R.; Thompson, A.W.

    1990-01-01

    The present conference discusses hydrogen permeation, trapping, and transport in metals, hydrogen-induced phase transformations, hydrogen embrittlement studies on stainless steels, hydrogen effects on advanced materials, hydrogen-associated fracture processes, crack growth susceptibility, and hydrogen-resistant engineering alloys and applications. Attention is given to the behavior of hydrogen in evaporated metal films, hydrogen diffusivity in alpha-beta Zr alloys, acoustic emissions from steels containing hydrogen, synergistic effects of He and H isotopes in FCC metals, hydrogen transport by dislocations in Al alloys, the effect of hydrogen precipitation in an Al-{sup 9}Mg alloy, hydrogen effects on Ti oxidation in water vapor, hydrogen effects on the behavior of duplex stainless steels, hydrogen embrittlement of superalloys, hydrogen embrittlement of TiAl alloys, hydrogen-enhanced decohesion in Fe-Si single crystals, cathodic hydrogen embrittlement of a duplex stainless steel, and hydrogen embrittlement in lean uranium alloys.

  19. 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.

  20. Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines

    SciTech Connect

    Soukhanovskii, V A; Johnson, D W; Kaita, R; Roquemore, A L

    2007-04-27

    Spatially resolved measurements of deuterium Balmer and Paschen line emission have been performed in the divertor region of the National Spherical Torus Experiment using a commercial 0.5 m Czerny-Turner spectrometer. While the Balmer emission lines, Balmer and Paschen continua in the ultraviolet and visible regions have been extensively used for tokamak divertor plasma temperature and density measurements, the diagnostic potential of infrared Paschen lines has been largely overlooked. We analyze Stark broadening of the lines corresponding to 2-n and 3-m transitions with principle quantum numbers n = 7-12 and m = 10-12 using recent Model Microfield Method calculations (C. Stehle and R. Hutcheon, Astron. Astrophys. Supl. Ser. 140, 93 (1999)). Densities in the range (5-50) x 10{sup 19} m{sup -3} are obtained in the recombining inner divertor plasma in 2-6 MW NBI H-mode discharges. The measured Paschen line profiles show good sensitivity to Stark effects, and low sensitivity to instrumental and Doppler broadening. The lines are situated in the near-infrared wavelength domain, where optical signal extraction schemes for harsh nuclear environments are practically realizable, and where a recombining divertor plasma is optically thin. These properties make them an attractive recombining divertor density diagnostic for a burning plasma experiment.

  1. 40 CFR 98.163 - Calculating GHG emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.163 Calculating GHG emissions. You must calculate and report the annual CO2 emissions from each hydrogen production process unit using the... associated with each fuel and feedstock used for hydrogen production by following paragraphs (b)(1)...

  2. 40 CFR 98.163 - Calculating GHG emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.163 Calculating GHG emissions. You must calculate and report the annual CO2 emissions from each hydrogen production process unit using the... associated with each fuel and feedstock used for hydrogen production by following paragraphs (b)(1)...

  3. 40 CFR 98.163 - Calculating GHG emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.163 Calculating GHG emissions. You must calculate and report the annual CO2 emissions from each hydrogen production process unit using the... associated with each fuel and feedstock used for hydrogen production by following paragraphs (b)(1)...

  4. 40 CFR 98.163 - Calculating GHG emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.163 Calculating GHG emissions. You must calculate and report the annual CO2 emissions from each hydrogen production process unit using the... associated with each fuel and feedstock used for hydrogen production by following paragraphs (b)(1)...

  5. Comparative costs and benefits of hydrogen vehicles

    SciTech Connect

    Berry, G.D.

    1996-10-01

    The costs and benefits of hydrogen as a vehicle fuel are compared to gasoline, natural gas, and battery-powered vehicles. Costs, energy, efficiency, and tail-pipe and full fuel cycle emissions of air pollutants and greenhouse gases were estimated for hydrogen from a broad range of delivery pathways and scales: from individual vehicle refueling systems to large stations refueling 300 cars/day. Hydrogen production from natural gas, methanol, and ammonia, as well as water electrolysis based on alkaline or polymer electrolytes and steam electrolysis using solid oxide electrolytes are considered. These estimates were compared to estimates for competing fuels and vehicles, and used to construct oil use, air pollutant, and greenhouse gas emission scenarios for the U.S. passenger car fleet from 2005-2050. Fuel costs need not be an overriding concern in evaluating the suitability of hydrogen as a fuel for passenger vehicles. The combined emissions and oil import reduction benefits of hydrogen cars are estimated to be significant, valued at up to {approximately}$400/yr for each hydrogen car when primarily clean energy sources are used for hydrogen production. These benefits alone, however, become tenuous as the basis supporting a compelling rationale for hydrogen fueled vehicles, if efficient, advanced fossil-fuel hybrid electric vehicles (HEV`s) can achieve actual on-road emissions at or below ULEV standards in the 2005-2015 timeframe. It appears a robust rationale for hydrogen fuel and vehicles will need to also consider unique, strategic, and long-range benefits of hydrogen vehicles which can be achieved through the use of production, storage, delivery, and utilization methods for hydrogen which are unique among fuels: efficient use of intermittent renewable energy sources, (e,g, wind, solar), small-scale feasibility, fuel production at or near the point of use, electrolytic production, diverse storage technologies, and electrochemical conversion to electricity.

  6. 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.

  7. Shocked Post-starbust Galaxy Survey: Candidate Post-Starbust Galaxies with Narrow Emission Line Ratios Arising from Shocks

    NASA Astrophysics Data System (ADS)

    Cales, Sabrina; Alatalo, Katherine A.; Appleton, Philip N.; Lisenfeld, Ute; Rich, Jeffrey; Nyland, Kristina; Lacy, Mark; Kewley, Lisa J.

    2015-01-01

    As galaxies age they move from the blue cloud (star forming) to the red sequence (`dead' galaxies) in the color-magnitude diagram of galaxies. Galaxies between the blue cloud and red sequence (i.e., the green valley) are caught in the act of transitioning and they show large Balmer jump and high order Balmer absorption lines in their optical spectra. These galaxies answer to many names (i.e., E+A, K+A, Hdelta-strong, post-starburst), all with similar but slightly different selection criteria. Many studies of transitioning galaxies invoke strong constraints on emission lines in order to guarantee a dominant post-starburst (rather that actively star bursting) stellar population, however these constraints bias the sample against narrow-line emission not arising from star formation, namely active galactic nuclei, low-ionization nuclear emission regions and shocks. Using the Oh-Sarzi-Schawinski-Yi (OSSY) emission and absorption line measurements for SDSS DR7 galaxies we study the intersection between transitioning galaxies and those with shock line ratios. We show that a significant fraction of transitioning galaxies have emission-line ratios indicative of shocks. We postulate that these shocks may be in part responsible for the shepherding of blue star forming galaxies to passive early-types.

  8. 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.

  9. Galactic Diffuse Emissions

    SciTech Connect

    Digel, Seth W.; /SLAC

    2007-10-25

    Interactions of cosmic rays with interstellar nucleons and photons make the Milky Way a bright, diffuse source of high-energy {gamma}-rays. Observationally, the results from EGRET, COMPTEL, and OSSE have now been extended to higher energies by ground-based experiments, with detections of diffuse emission in the Galactic center reported by H.E.S.S. in the range above 100 GeV and of diffuse emission in Cygnus by MILAGRO in the TeV range. In the range above 100 keV, INTEGRAL SPI has found that diffuse emission remains after point sources are accounted for. I will summarize current knowledge of diffuse {gamma}-ray emission from the Milky Way and review some open issues related to the diffuse emission -- some old, like the distribution of cosmic-ray sources and the origin of the 'excess' of GeV emission observed by EGRET, and some recently recognized, like the amount and distribution of molecular hydrogen not traced by CO emission -- and anticipate some of the advances that will be possible with the Large Area Telescope on GLAST. We plan to develop an accurate physical model for the diffuse emission, which will be useful for detecting and accurately characterizing emission from Galactic point sources as well as any Galactic diffuse emission from exotic processes, and for studying the unresolved extragalactic emission.

  10. Solar powered hydrogen generating facility and hydrogen powered vehicle fleet. Final technical report, August 11, 1994--January 6, 1997

    SciTech Connect

    Provenzano, J.J.

    1997-04-01

    This final report describes activities carried out in support of a demonstration of a hydrogen powered vehicle fleet and construction of a solar powered hydrogen generation system. The hydrogen generation system was permitted for construction, constructed, and permitted for operation. It is not connected to the utility grid, either for electrolytic generation of hydrogen or for compression of the gas. Operation results from ideal and cloudy days are presented. The report also describes the achievement of licensing permits for their hydrogen powered trucks in California, safety assessments of the trucks, performance data, and information on emissions measurements which demonstrate performance better than the Ultra-Low Emission Vehicle levels.

  11. Emission Abatement System

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander

    2003-05-13

    Emission abatement system. The system includes a source of emissions and a catalyst for receiving the emissions. Suitable catalysts are absorber catalysts and selective catalytic reduction catalysts. A plasma fuel converter generates a reducing gas from a fuel source and is connected to deliver the reducing gas into contact with the absorber catalyst for regenerating the catalyst. A preferred reducing gas is a hydrogen rich gas and a preferred plasma fuel converter is a plasmatron. It is also preferred that the absorber catalyst be adapted for absorbing NO.sub.x.

  12. The Hα and Hβ emissions in solar prominence structures.

    NASA Astrophysics Data System (ADS)

    Stellmacher, G.; Wiehr, E.

    1994-10-01

    High precision photometry of the Halpha_ and Hbeta_ emissions is performed from spectra of four spatially high resolved quiescent prominences. The data are compared with recent observations and calculations. It is found that for faint emissions the observed Balmer decrement D=E_tot_(Halpha_)/E_tot_(Hbeta_) significantly exceeds the limiting value D=10.0 calculated for slab models. In contrast to former observations, the spatially and spectrally high resolved emission profiles do not require a hot and a cool component for an optimal fit. The deduced source functions do not yield a common value for different prominences, but show an individual mean for each prominence with a tendency for an increase with the optical thickness of Halpha_. Optically thick Halpha_ emissions with central absorptions are spatially related with narrow Hbeta_ emissions and hence with small kinetic temperatures. The narrow Hbeta_ emissions exist over a large range of optical thickness and show equal macroscopic shifts for individual emission features favouring a picture of closely tied bundles of threads.

  13. 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

  14. 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

  15. Role of the medium on the C343 inter/intramolecular hydrogen bond interactions. An absorption, emission, and 1HNMR investigation of C343 in benzene/n-heptane mixtures.

    PubMed

    Gutierrez, Jorge A; Falcone, R Darío; Silber, Juana J; Correa, N Mariano

    2010-07-15

    C343, a common molecular probe utilized in solvation dynamics experiments, was studied in homogeneous media. Absorption, emission, and (1)HNMR spectroscopies were used to investigate the behavior of C343 in benzene and in benzene/n-heptane mixtures. We demonstrate the implications of the medium polarity, measured as the Kamlet-Taft polarity-polarizability (pi*) parameter, in the C343 inter/intramolecular hydrogen bond (H-bond) interactions and the role that this interaction plays in the dimerization process of the dye. In pure benzene, the dimer prevails because the intermolecular H-bond interaction is favored. On the other hand, as the n-heptane content increases the intramolecular H-bond is the strongest and the C343 monomer is favored. As the polarity of the medium decreases, the solvophobic interaction makes that C343 monomer species experiences a more complicated aggregation process beyond the simple monomer dimer equilibrium present in pure benzene. Thus, the addition of n-heptane to the mixture yields a C343 higher-order aggregates species. Thus, our work reveals the importance that the medium has on the behavior of a widespread dye used as chromophore for very different systems such as homogeneous and microheterogenous media. This is very important since the use of chromophores without understanding its chemistry can induce artifacts into the interpretation of solvation dynamics in heterogeneous environments, in particular, those provided by biological systems such as proteins. Considerable care in choosing and characterizing the system is required to analyze the results fully. PMID:20565101

  16. 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.

  17. Hydrogen powered aircraft : The future of air transport

    NASA Astrophysics Data System (ADS)

    Khandelwal, Bhupendra; Karakurt, Adam; Sekaran, Paulas R.; Sethi, Vishal; Singh, Riti

    2013-07-01

    This paper investigates properties and traits of hydrogen with regard to environmental concerns and viability in near future applications. Hydrogen is the most likely energy carrier for the future of aviation, a fuel that has the potential of zero emissions. With investigation into the history of hydrogen, this study establishes issues and concerns made apparent when regarding the fuel in aero applications. Various strategies are analyzed in order to evaluate hydrogen's feasibility which includes production, storage, engine configurations and aircraft configurations.

  18. Hydrogen: Adding Value and Flexibility to the Nuclear Power Industry

    SciTech Connect

    Lee, J.; Bhatt, V.; Friley, P.; Horak, W.; Reisman, A.

    2004-10-04

    The objective of this study was to assess potential synergies between the hydrogen economy and nuclear energy options. Specifically: to provide a market analysis of advanced nuclear energy options for hydrogen production in growing hydrogen demand; to conduct an impact evaluation of nuclear-based hydrogen production on the economics of the energy system, environmental emissions, and energy supply security; and to identify competing technologies & challenges to nuclear options.

  19. 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 effects of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed.

  20. Hydrogen production by photosynthetic microorganisms

    SciTech Connect

    Akano, T.; Fukatsu, K.; Miyasaka, H. |

    1996-12-31

    Hydrogen is a clean energy alternative to the fossil fuels, the main source of greenhouse gas emissions. We developed a stable system for the conversion of solar energy into hydrogen using photosynthetic microorganisms. Our system consists of the following three stages: (1) Photosynthetic starch accumulation in green microalgae (400 L x2); (2) Dark anaerobic fermentation of the algal starch biomass to produce hydrogen and organic compounds (155 L x2); and (3) Further conversion of the organic compounds to produce hydrogen using photosynthetic bacteria (three types of reactors, parallel plate, raceway, and tubular). We constructed a test plant of this process at Nankoh power plant of Kansai Electric Power Company in Osaka, Japan, and carried out a series of tests using CO{sub 2} obtained from a chemical absorption pilot-plant. The photobiological hydrogen production process used a combination of a marine alga, Chlamydomonas sp. MGA 161 and marine photosynthetic bacterium, Rhodopseudomonas sp. W-1S. The dark anaerobic fermentation of algal starch biomass was also investigated. Sustained and stable starch accumulation, starch degradation in the algal cell, and hydrogen production from algal fermentation and photosynthetic bacteria in the light were demonstrated during several experiments. 3 refs., 12 figs., 1 tab.

  1. Dairy gas emissions model: reference manual

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Dairy Gas Emissions Model (DairyGEM) is a software tool for estimating ammonia, hydrogen sulfide, and greenhouse gas (GHG) emissions of dairy production systems as influenced by climate and farm management. A production system is defined to include emissions during the production of all feeds wh...

  2. 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.

  3. Modeling of neutral hydrogen velocities in the Tokamak Fusion Test Reactor

    NASA Astrophysics Data System (ADS)

    Stotler, D. P.; Skinner, C. H.; Budny, R. V.; Ramsey, A. T.; Ruzic, D. N.; Turkot, R. B., Jr.

    1996-11-01

    Monte Carlo neutral transport simulations of hydrogen velocities in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire et al., Phys. Plasmas 2, 2176 (1995)] are compared with experiment using the Doppler-broadened Balmer-α spectral line profile. Good agreement is obtained under a range of conditions, validating the treatment of charge exchange, molecular dissociation, surface reflection, and sputtering in the neutral gas code DEGAS [D. Heifetz et al., J. Comput. Phys. 46, 309 (1982)]. A residual deficiency of 10-100 eV neutrals in most of the simulations indicates that further study of the energetics of H+2 dissociation for electron energies in excess of 100 eV is needed.

  4. Bound-bound transitions in hydrogen-like ions in dense quantum plasmas

    NASA Astrophysics Data System (ADS)

    Qi, Y. Y.; Wang, J. G.; Janev, R. K.

    2016-07-01

    The properties of bound-bound transitions in hydrogen-like ions in dense quantum plasmas, characterized by a cosine-Debye-Hückel interaction between charged particles, are studied in detail. The transition frequencies, oscillator strengths, and radiative transition probabilities of Lyman and Balmer series are calculated for a wide range of screening strengths of the interaction up to the n = 5 shell. For Δ n ≠ 0 transitions, all these quantities exhibit a significant decrease with increasing screening strength, while for the Δ n = 0 transitions and for the radiative lifetimes, the opposite is true. The present results are compared with those available from the literature. They are also compared with the results for the pure Debye-Hückel potential with the same screening strength.

  5. The extended atmosphere of Lambda Pavonis at the time of the emergence of H-emissions from minimum intensity

    NASA Technical Reports Server (NTRS)

    Sahade, Jorge; Rovira, Marta; Ringuelet, Adela E.; Kondo, Yoji; Cidale, Lydia

    1988-01-01

    A study of the Be star Lambda Pavonis, particularly of the changes in the Balmer discontinuity in the interval 1949-1982, is presented. Nearly simultaneous observations carried out with the ESO 1.5 m reflector at La Silla and with the IUE satellite correspond to an epoch when the H emission is starting to increase intensity immediately after having reached its minimum strength. These observations suggest the presence of four distinct regions of line formation, with the material moving outward in the transition region.

  6. Emission line flaring in the SW Sex old nova V533 Herculis

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gil, Pablo; Martínez-Pais, Ignacio G.

    2002-11-01

    We present high time resolution spectroscopy of the non-eclipsing old nova V533 Herculis (N Her 1963). It is the second nova remnant affected by the `SW Sex syndrome'. A modulation of the equivalent width of the emission lines with a period of 23.33 min has been detected. This, together with the strong He II λ4686 emission characteristic of magnetic systems, leads us to link this period to the spin of a magnetic white dwarf. Similar flaring activity has been recorded in other SW Sex stars, namely, the old nova BT Mon, LS Peg and DW UMa, supporting the idea of these systems being magnetic accretors. Stationary emission features are also observed in the Balmer lines, which we attribute to the ejected nova shell.

  7. V533 Herculis: the second SW Sex old nova displaying emission-line flaring

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gil, P.; Martínez-Pais, I. G.

    2002-11-01

    We present high-time-resolution spectroscopy of the non-eclipsing old nova V533 Herculis (N Her 1963). It is the second nova remnant affected by the `SW Sex syndrome'. A modulation of the equivalent width of the emission lines with a period of 23.33 min has been detected. This, together with the strong He IIλ4686 emission characteristic of magnetic systems, leads us to link this period to the spin of a magnetic white dwarf. Similar flaring activity has been recorded in other SW Sex stars, namely, the old nova BT Mon, LS Peg and DW UMa, supporting the idea of these systems being magnetic accretors. Stationary emission features are also observed in the Balmer lines, which we attribute to the ejected nova shell.

  8. 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.

  9. Hydrogen-Assisted IC Engine Combustion as a Route to Hydrogen Implementation

    SciTech Connect

    Andre Boehman; Daniel Haworth

    2008-09-30

    The 'Freedom Car' Initiative announced by the Bush Administration has placed a significant emphasis on development of a hydrogen economy in the United States. While the hydrogen-fueled fuel-cell vehicle that is the focus of the 'Freedom Car' program would rely on electrochemical energy conversion, and despite the large amount of resources being devoted to its objectives, near-term implementation of hydrogen in the transportation sector is not likely to arise from fuel cell cars. Instead, fuel blending and ''hydrogen-assisted'' combustion are more realizable pathways for wide-scale hydrogen utilization within the next ten years. Thus, a large potential avenue for utilization of hydrogen in transportation applications is through blending with natural gas, since there is an existing market for natural-gas vehicles of various classes, and since hydrogen can provide a means of achieving even stricter emissions standards. Another potential avenue is through use of hydrogen to 'assist' diesel combustion to permit alternate combustion strategies that can achieve lower emissions and higher efficiency. This project focused on developing the underlying fundamental information to support technologies that will facilitate the introduction of coal-derived hydrogen into the market. Two paths were envisioned for hydrogen utilization in transportation applications. One is for hydrogen to be mixed with other fuels, specifically natural gas, to enhance performance in existing natural gas-fueled vehicles (e.g., transit buses) and provide a practical and marketable avenue to begin using hydrogen in the field. A second is to use hydrogen to enable alternative combustion modes in existing diesel engines, such as homogeneous charge compression ignition, to permit enhanced efficiency and reduced emissions. Thus, this project on hydrogen-assisted combustion encompassed two major objectives: (1) Optimization of hydrogen-natural gas mixture composition and utilization through laboratory

  10. Discovery of Polarized Line Emission in SN 1006

    NASA Astrophysics Data System (ADS)

    Sparks, W. B.; Pringle, J. E.; Carswell, R. F.; Long, K. S.; Cracraft, M.

    2015-12-01

    Laming predicted that the narrow Balmer line core of the ∼3000 km s‑1 shock in the SN 1006 remnant would be significantly polarized due to electron and proton impact polarization. Here, based on deep spectrally resolved polarimetry obtained with the European Southern Observatory (ESO)’s Very Large Telescope (VLT), we report the discovery of polarized line emission with a polarization degree of 1.3% and position angle orthogonal to the SNR filament. Correcting for an unpolarized broad line component, the implied narrow line polarization is ≈2.0%, close to the predictions of Laming. The predicted polarization is primarily sensitive to shock velocity and post-shock temperature equilibration. By measuring polarization for the SN 1006 remnant, we validate and enable a new diagnostic that has important applications in a wide variety of astrophysical situations, such as shocks, intense radiation fields, high energy particle streams, and conductive interfaces.

  11. Continuum emission in the 1980 July 1 solar flare

    NASA Technical Reports Server (NTRS)

    Zirin, H.; Neidig, D. F.

    1981-01-01

    Comparison of continuum measurements of the July 1, 1980 flare at Big Bear Solar Observatory and Sacramento Peak Observatory show strong blue emission kernels with the ratio of Balmer continuum (Bac):3862 A continuum:continuum above 4275 A to be about 10:5:1. The blue continuum at 3862 A is too strong to be explained by unresolved lines. The Bac intensity was 2.5 times the photosphere and the strongest 3826 A continuum was 2 times the photosphere. The brightest continuum kernel occurred late in the flare, after the hard X-ray peak and related in time to an isolated peak in the 2.2 MeV line, suggesting that that continuum was excited by protons above 20 MeV.

  12. New potentials for conventional aircraft when powered by hydrogen-enriched gasoline

    NASA Technical Reports Server (NTRS)

    Menard, W. A.; Moynihan, P. I.; Rupe, J. H.

    1976-01-01

    Hydrogen enrichment for aircraft piston engines is studied. The feasibility is examined of inflight injection of hydrogen in general aviation aircraft engines to reduce fuel consumption and to lower emission levels. Results are summarized.

  13. Measurement of Gas Temperature in Negative Hydrogen Ion Source by Wavelength-Modulated Laser Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nishiyama, S.; Sasaki, K.; Nakano, H.; Goto, M.; Kisaki, M.; Tsumori, K.; NIFS-NBI Team

    2014-10-01

    Measurement of the energy distribution of hydrogen atom is important and essential to understand the production mechanism of its negative ion (H-) in cesium-seeded negative ion sources. In this work, we evaluated the temperature of atomic hydrogen in the large-scale arc-discharge negative hydrogen ion source in NIFS by wavelength-modulated laser absorption spectroscopy. The laser beam was passed through the adjacent region to the grid electrode for extracting negative ions. The frequency of the laser was scanned slowly over the whole range of the Doppler width (100 GHz in 1s). A sinusoidal frequency modulation at 600 Hz with a width of 30 GHz was superposed onto the slow modulation. The transmitted laser was detected using a photodiode, and its second harmonic component of the sinusoidal modulation was amplified using a lock-in amplifier. The obtained spectrum was in good agreement with an expected spectrum of the Doppler-broadened Balmer- α line. The estimated temperature of atomic hydrogen was approximately 3000 K. The absorption increased with the arc-discharge power, while the temperature was roughly independent of the power. This work is supported by the NIFS Collaboration Research Program NIFS13KLER021.

  14. 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.

  15. Spectropolarimetry of V854 Centauri at minimum light - Clues to the geometry of the dust and emission-line region

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.; Clayton, Geoffrey C.; Schulte-Ladbeck, Regina E.; Meade, Marilyn R.

    1992-01-01

    The RCB star V854 Cen is observed during a very deep decline (Delta m = 8.2) at the AAT. The continuum polarization is very high, ranging from 14 percent at 4200 A to about 4 percent at 6500 A. The polarization decreases across the emission lines, but the polarized flux remains constant. This indicates that the emission lines are unpolarized, so the emission probably arises in a region unobscured by dust. In such a deep minimum, the visible continuum flux is probably almost entirely scattered light, which explains its high polarization. The scattered flux may arise in the same clouds contributing to the observed IR flux if the albedo is low and the grains forward throwing. The emission-line spectrum itself is very unusual for an RCB star in decline, with strong C2 bands and Balmer lines.

  16. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  17. Hydrogen delivery technology rRoadmap

    SciTech Connect

    None, None

    2005-11-01

    Hydrogen holds the long-term potential to solve two critical problems related to the energy infrastructure: U.S. dependence on foreign oil and U.S. emissions of greenhouse gases and pollutants. The U.S. transportation sector is almost completely reliant on petroleum, over half of which is currently imported, and tailpipe emissions remain one of the country’s key air quality concerns. Fuel cell vehicles operating on hydrogen produced from domestically available resources – including renewable resources, coal with carbon sequestration, or nuclear energy – would dramatically decrease greenhouse gases and other emissions, and would reduce dependence on oil from politically volatile regions of the world. Clean, domestically-produced hydrogen could also be used to generate electricity in stationary fuel cells at power plants, further extending national energy and environmental benefits.

  18. 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.

  19. 40 CFR Table 2 to Subpart Ffff of... - Emission Limits and Work Practice Standards for Batch Process Vents

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... halogen reduction device after the combustion control device; or i. Reduce overall emissions of hydrogen halide and halogen HAP by ≥99 percent; orii. Reduce overall emissions of hydrogen halide and halogen HAP to ≤0.45 kg/hr; or iii. Reduce overall emissions of hydrogen halide and halogen HAP to...

  20. 40 CFR Table 2 to Subpart Ffff of... - Emission Limits and Work Practice Standards for Batch Process Vents

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... device; or i. Reduce overall emissions of hydrogen halide and halogen HAP by ≥99 percent; orii. Reduce overall emissions of hydrogen halide and halogen HAP to ≤0.45 kg/hr; or iii. Reduce overall emissions of hydrogen halide and halogen HAP to a concentration ≤20 ppmv. b. Use a halogen reduction device before...