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Sample records for hydrogen depth distribution

  1. Measurements of the electrical resistance and the hydrogen depth distribution for Ni 60Nb 20Zr 20 amorphous alloy before and after hydrogen charging

    Science.gov (United States)

    Nakano, Sumiaki; Ohtsu, Naofumi; Nagata, Shinji; Yamaura, Shin-ichi; Uchinashi, Sakae; Kimura, Hisamichi; Shikama, Tatsuo; Inoue, Akihisa

    2005-02-01

    A Ni 60Nb 20Zr 20 amorphous alloy was prepared by the single-roller melt-spinning technique. The change in the electrical resistance of the alloy after electrochemical hydrogen charging in 6 N KOH solution was investigated. The change in the hydrogen depth distribution in the alloy was also investigated by elastic recoil detection. As a result, we found that the electrical resistance of the alloy increases with increasing the hydrogen content in the alloy and that a large number of hydrogen atoms are remained in the surface area of the hydrogen-charged alloy.

  2. Distribution in depth of quasars

    International Nuclear Information System (INIS)

    Schmidt, M.; Green, R.F.

    1980-01-01

    The authors discuss the distribution in depth of different kinds of quasars: quasi-stellar radio sources with steep radio spectrum, those with flat radio spectrum, and optically selected quasars. All exhibit an increase of space density with distance to a different degree. The optically selected quasars, in particular, show a steep increase of surface density with magnitude. The steepness of the increase is inconsistent with a uniform distribution of quasars in the local hypothesis. In the cosmological hypothesis the co-moving space density of optically selected quasars increases by a factor of 100,000 to a redshift of 2, and by factors of 1000 and 10 for steep-spectrum and flat-spectrum radio quasars, respectively. (Auth.)

  3. Model for hydrogen isotope backscattering, trapping and depth profiles in C and a-Si

    International Nuclear Information System (INIS)

    Cohen, S.A.; McCracken, G.M.

    1979-03-01

    A model of low energy hydrogen trapping and backscattering in carbon and a-silicon is described. Depth profiles are calculated and numerical results presented for various incident angular and energy distributions. The calculations yield a relation between depth profiles and the incident ion energy distribution. The use of this model for tokamak plasma diagnosis is discussed

  4. Measuring hydrogen-isotope distribution profiles

    International Nuclear Information System (INIS)

    Poppe, C.H.

    1977-01-01

    A new nondestructive technique was developed for measuring the depth distribution of hydrogen isotopes absorbed or implanted near the surface of any material. The method allows real-time study of the inventory and diffusion of hydrogen, deuterium, and tritium. Briefly, the technique involves bombarding the surface with a monoenergetic beam of ions chosen for their ability to react with the hydrogen isotope in question and produce fast neutrons. The energy distribution of the neutrons is a sensitive indicator of the energy of the bombarding particles at the instant of reaction, and hence of the depth of the reaction sites below he surface of the material. A sensitivity of one part per million was obtained for tritium in copper. The technique is applicable to several energy-related materials problems. 5 figures

  5. Hydrogen depth distribution and fatigue properties of TiAl6V4 with implanted nitrogen; Wasserstoff-Tiefenverteilung und Ermuedungseigenschaften von Stickstoff-implantiertem TiAl6V4

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, H. [Technische Univ. Darmstadt (Germany). Fachbereich Materialwissenschaft; Rueck, D.M. [Gesellschaft fuer Schwerionenforschung mbH (GSI), Darmstadt (Germany). Abt. fuer Materialforschung; Soltani-Farshi, M.; Baumann, H. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik

    1998-12-31

    Depth distributions and cracking initiation were analysed in TiAl6V4 with implanted nitrogen by means of high-energy backscattering spectroscopy, nuclear reaction analysis and fatigue tests under rotary bending loads. The hydrogen content in the substrate is approx. 0.4 at.%. The hydrogen content in the materials layer with implanted nitrogen is up to 2.6 at%. The highest hydrogen concentration was found in material consisting of titanium nitride (TiN) and {alpha}-titanium. In areas with high nitrogen accumulation, where a consistent TiN layer is formed, the hydrogen content is lower than 1.5 at.%. Nitrogen ion implantation was not found to significantly reduce the fatigue strength of the specimens tested under rotary bending loads, although fatigue-induced cracking primarily occurs in specimen zones where the maximum concentrations of hydrogen and nitrogen are close to the surface. (orig./CB) [Deutsch] Tiefenverteilungen und die Rissbildung von Stickstoff-implantiertem TiAl6V4 wurden mittels Hochenergie-Rueckstreu-Spektroskopie, Kernreaktionsanalyse und Umlaufbiegetests untersucht. Der Wasserstoffgehalt im Substrat betraegt etwa 0,4 at.%. In der Stickstoff-implantierten Schicht wird eine Wasserstoffakkumulation bis zu 2,6 at% beobachtet. Die hoechste Wasserstoffkonzentration tritt auf, wenn eine Mischung aus Titannitrid (TiN) und mit Stickstoff angereichertem {alpha}-Titan vorliegt. In Bereichen hoher Stickstoffanreicherung, in denen eine zusammenhaengende TiN-Schicht gebildet wird, sinkt der Wasserstoffanteil unter 1,5 at.% ab. Die Stickstoff-Implantation senkt die Lebensdauern im Umlaufbiegeversuch nicht signifikant ab, obwohl die Ermuedungsrisse bevorzugt von Probenbereichen ausgehen, in denen die Maximalgehalte von Stickstoff und Wasserstoff nahe an der Oberflaeche liegen. (orig.)

  6. Hydrogen depth profiling using elastic recoil detection

    International Nuclear Information System (INIS)

    Doyle, B.L.; Peercy, P.S.

    1979-01-01

    The elastic recoil detection (ERD) analysis technique for H profiling in the near surface regions of solids is described. ERD is shown to have the capability of detecting H and its isotopes down to concentrations of approx. 0.01 at. % with a depth resolution of a few hundred angstroms. Is is demonstrated that 2.4-MeV He ions can be used successfully to profile 1 H and 2 D using this technique. 12 figures

  7. The Beryllium 7 Depth Distribution Study

    International Nuclear Information System (INIS)

    Jalal Sharib; Zainudin Othman; Dainee Nor Fardzila Ahmad Tugi

    2014-01-01

    The aim of this paper is to study the evolution of 7Be depth distribution in a soil profile. The soil samples have been collected by using plastic core in bare area in Bangi, Malaysia. Each of the soil core samples has been sectioned into 2 mm increments to a depth of 4 cm and the samples are subsequently oven dried at 45°C and gently disaggregated. The sample is passed through a < 2 mm sieve and packed into plastic pot for 7Be analysis using gamma spectrometry with a 24 hour count time. From the findings, show the 7Be depth penetration from this study decreases exponentially with depth and is confined within the top few centimeters and similar with other works been reported. The further discussion for this findings will be presented in full paper. (author)

  8. Zero emission distributed hydrogen production

    International Nuclear Information System (INIS)

    Maddaloni, J.; Rowe, A.; Bailey, R.; McDonald, J.D.

    2004-01-01

    The need for distributed production facilities has become a critical issue in developing a hydrogen infrastructure. Hydrogen generation using processes that make effective use of what would normally be considered waste streams or process inefficiencies can have more favorable economics than stand-alone technologies. Currently, natural gas is distributed to industrial and residential customers through a network of pipelines. High pressure main lines move gas to the vicinity of consumers where the pressure is reduced for local, low pressure distribution. Often, the practice is to use an isenthalpic expansion which results in a cooling of the gas stream. Some of the natural gas is burned to preheat the fuel so that the temperature after the expansion is near ambient. This results in the destruction of exergy in the high pressure gas stream and produces CO 2 in the process. If, instead, a turbo-expander is used to reduce the stream pressure, work can be recovered using a generator and hydrogen can be produced via electrolysis. This method of hydrogen production is free of green-house gas emissions, makes use of existing gas distribution facilities, and uses exergy that would otherwise be destroyed. Pressure reduction using the work producing process (turbo-expander) is accompanied by a large drop in temperature, on the average of 70 K. The local gas distributor requires the gas temperature to be raised again to near 8 o C to prevent damage to valve assemblies. The required heating power after expansion can be on the order of megawatts (site dependent.) Supplying the heat can be seen as a cost if energy is taken from the system to reheat the fuel; however, the low temperature stream may also be considered an asset if the cooling power can be used for a local process. This analysis is the second stage of a study to examine the technical and economic feasibility of using pressure let-down sites as hydrogen production facilities. This paper describes a proposed

  9. Density distributions and depth in flocks

    Science.gov (United States)

    Lewis, J. M.; Turner, M. S.

    2017-12-01

    Recent experimental evidence suggests that interactions in flocks of birds do not involve a characteristic length scale. Bird flocks have also been revealed to have an inhomogeneous density distribution, with the density of birds near the border greater than near the centre. We introduce a strictly metric-free model for collective behaviour that incorporates a distributed motional bias, providing control of the density distribution. A simple version of this model is then able to provide a good fit to published data for the density variation across flocks of Starlings. We find that it is necessary for individuals on the edge of the flock to have an inward motional bias but that birds in the interior of the flock instead must have an outward bias. We discuss the ability of individuals to determine their depth within a flock and show how this might be achieved by relatively simple analysis of their visual environment.

  10. Hydrogen analysis depth calibration by CORTEO Monte-Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moser, M., E-mail: marcus.moser@unibw.de [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Reichart, P.; Bergmaier, A.; Greubel, C. [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Schiettekatte, F. [Université de Montréal, Département de Physique, Montréal, QC H3C 3J7 (Canada); Dollinger, G., E-mail: guenther.dollinger@unibw.de [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany)

    2016-03-15

    Hydrogen imaging with sub-μm lateral resolution and sub-ppm sensitivity has become possible with coincident proton–proton (pp) scattering analysis (Reichart et al., 2004). Depth information is evaluated from the energy sum signal with respect to energy loss of both protons on their path through the sample. In first order, there is no angular dependence due to elastic scattering. In second order, a path length effect due to different energy loss on the paths of the protons causes an angular dependence of the energy sum. Therefore, the energy sum signal has to be de-convoluted depending on the matrix composition, i.e. mainly the atomic number Z, in order to get a depth calibrated hydrogen profile. Although the path effect can be calculated analytically in first order, multiple scattering effects lead to significant deviations in the depth profile. Hence, in our new approach, we use the CORTEO Monte-Carlo code (Schiettekatte, 2008) in order to calculate the depth of a coincidence event depending on the scattering angle. The code takes individual detector geometry into account. In this paper we show, that the code correctly reproduces measured pp-scattering energy spectra with roughness effects considered. With more than 100 μm thick Mylar-sandwich targets (Si, Fe, Ge) we demonstrate the deconvolution of the energy spectra on our current multistrip detector at the microprobe SNAKE at the Munich tandem accelerator lab. As a result, hydrogen profiles can be evaluated with an accuracy in depth of about 1% of the sample thickness.

  11. A method to measure depth distributions of implanted ions

    International Nuclear Information System (INIS)

    Arnesen, A.; Noreland, T.

    1977-04-01

    A new variant of the radiotracer method for depth distribution determinations has been tested. Depth distributions of radioactive implanted ions are determined by dissolving thin, uniform layers of evaporated material from the surface of a backing and by measuring the activity before and after the layer removal. The method has been used to determine depth distributions for 25 keV and 50 keV 57 Co ions in aluminium and gold. (Auth.)

  12. Storage, transmission and distribution of hydrogen

    Science.gov (United States)

    Kelley, J. H.; Hagler, R., Jr.

    1979-01-01

    Current practices and future requirements for the storage, transmission and distribution of hydrogen are reviewed in order to identify inadequacies to be corrected before hydrogen can achieve its full potential as a substitute for fossil fuels. Consideration is given to the storage of hydrogen in underground solution-mined salt caverns, portable high-pressure containers and dewars, pressure vessels and aquifers and as metal hydrides, hydrogen transmission in evacuated double-walled insulated containers and by pipeline, and distribution by truck and internal distribution networks. Areas for the improvement of these techniques are indicated, and these technological deficiencies, including materials development, low-cost storage and transmission methods, low-cost, long-life metal hydrides and novel methods for hydrogen storage, are presented as challenges for research and development.

  13. Hydrogen depth resolution in multilayer metal structures, comparison of elastic recoil detection and resonant nuclear reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Wielunski, L.S. E-mail: leszekw@optushome.com.au; Grambole, D.; Kreissig, U.; Groetzschel, R.; Harding, G.; Szilagyi, E

    2002-05-01

    Four different metals: Al, Cu, Ag and Au have been used to produce four special multilayer samples to study the depth resolution of hydrogen. The layer structure of each sample was analysed using 2 MeV He Rutherford backscattering spectrometry, 4.5 MeV He elastic recoil detection (ERD) and 30 MeV F{sup 6+} HIERD. Moreover the hydrogen distribution was analysed in all samples using H({sup 15}N, {alpha}{gamma}){sup 12}C nuclear reaction analysis (NRA) with resonance at 6.385 MeV. The results show that the best depth resolution and sensitivity for hydrogen detection are offered by resonance NRA. The He ERD shows good depth resolution only for the near surface hydrogen. In this technique the depth resolution is rapidly reduced with depth due to multiple scattering effects. The 30 MeV F{sup 6+} HIERD demonstrated similar hydrogen depth resolution to He ERD for low mass metals and HIERD resolution is substantially better for heavy metals and deep layers.

  14. Fish depth distributions in the Lower Mississippi River

    Science.gov (United States)

    Killgore, K. J.; Miranda, Leandro E.

    2014-01-01

    A substantial body of literature exists about depth distribution of fish in oceans, lakes and reservoirs, but less is known about fish depth distribution in large rivers. Most of the emphasis on fish distributions in rivers has focused on longitudinal and latitudinal spatial distributions. Knowledge on depth distribution is necessary to understand species and community habitat needs. Considering this void, our goal was to identify patterns in fish benthic distribution along depth gradients in the Lower Mississippi River. Fish were collected over 14 years in depths down to 27 m. Fish exhibited non-random depth distributions that varied seasonally and according to species. Species richness was highest in shallow water, with about 50% of the 62 species detected no longer collected in water deeper than 8 m and about 75% no longer collected in water deeper than 12 m. Although richness was highest in shallow water, most species were not restricted to shallow water. Rather, most species used a wide range of depths. A weak depth zonation occurred, not as strong as that reported for deep oceans and lakes. Larger fish tended to occur in deeper water during the high-water period of an annual cycle, but no correlation was evident during the low-water period. The advent of landscape ecology has guided river research to search for spatial patterns along the length of the river and associated floodplains. Our results suggest that fish assemblages in large rivers are also structured vertically. 

  15. Depth Images Filtering In Distributed Streaming

    Directory of Open Access Journals (Sweden)

    Dziubich Tomasz

    2016-04-01

    Full Text Available In this paper, we propose a distributed system for point cloud processing and transferring them via computer network regarding to effectiveness-related requirements. We discuss the comparison of point cloud filters focusing on their usage for streaming optimization. For the filtering step of the stream pipeline processing we evaluate four filters: Voxel Grid, Radial Outliner Remover, Statistical Outlier Removal and Pass Through. For each of the filters we perform a series of tests for evaluating the impact on the point cloud size and transmitting frequency (analysed for various fps ratio. We present results of the optimization process used for point cloud consolidation in a distributed environment. We describe the processing of the point clouds before and after the transmission. Pre- and post-processing allow the user to send the cloud via network without any delays. The proposed pre-processing compression of the cloud and the post-processing reconstruction of it are focused on assuring that the end-user application obtains the cloud with a given precision.

  16. Hydrogen distribution studies relevant to CANDU containments

    International Nuclear Information System (INIS)

    Krause, M.; Whitehouse, D.R.; Chan, C.K.; Jones, S.C.A.

    1995-01-01

    Following a loss of coolant accident with coincident loss of emergency core cooling, hydrogen may be produced in a CANDU reactor from the in-core Zircaloy-steam reaction, and released into containment. To meet the requirements for predicting containment hydrogen distribution, and to support measures for mitigation, a computer code GOTHIC is used. Simulations of gas mixing were performed using simple well defined experiments in a small-scale compartment, helium being substituted for hydrogen. At the time of the conference, results indicated that GOTHIC could quantitatively predict the stratified gas distribution resulting from buoyant gas injection near the bottom of an unobstructed compartment. When gas was injected near the top, GOTHIC underpredicted maximum gas concentration at the top, and overpredicted mixing. These errors arise from the finite-volume approximation. 2 refs., 11 figs

  17. Depth profiling of hydrogen passivation of boron in Si(100)

    Science.gov (United States)

    Huang, L. J.; Lau, W. M.; Simpson, P. J.; Schultz, P. J.

    1992-08-01

    The properties of SiO2/p-Si were studied using variable-energy positron-annihilation spectroscopy and Raman spectroscopy. The oxide film was formed by ozone oxidation in the presence of ultraviolet radiation at room temperature. Both the positron-annihilation and Raman analyses show that chemical cleaning of boron-doped p-type Si(100) using concentrated hydrofluoric acid prior to the oxide formation leads to hydrogen incorporation in the semiconductor. The incorporated hydrogen passivates the boron dopant by forming a B-H complex, the presence of which increases the broadening of the line shape in the positron-annihilation analysis, and narrows the linewidth of the Raman peak. Annealing of the SiO2/Si sample at a moderate temperature of 220 °C in vacuum was found sufficient to dissociate the complex and reactivate the boron dopant.

  18. Use of nuclear reactions and ion channeling techniques for depth profiling hydrogen isotopes in solids

    International Nuclear Information System (INIS)

    Appleton, B.R.

    1979-01-01

    Hydrogen has always played a preeminent role in materials science because it so readily alters the physical and chemical properties of materials. However, it is often difficult to determine its role because it is one of the most elusive constituents to detect. More recently hydrogen detection has become necessary in numerous energy-related fields. In fusion energy one must understand plasma particle (hydrogen isotope) recycling, trapping and reemission, as well as the effects of hydrogen on the materials properties of first wall structures in plasma devices (i.e., hydrogen embrittlement, sputtering, blistering, etc.). In geology the presence of hydrogen in various forms alters the mechanical properties of many minerals in the earth's crust and enters directly into studies of tectonic processes. Evaluation of hydrogen in moon rocks increases our understanding of solar wind activity. In solar energy, hydrogen plays an important role in amorphous silicon used in fabricating solar cells. Detection of hydrogen is clearly important in the fossil fuel area. Many of the conventional elemental analysis techniques are not directly applicable to hydrogen determination and others can only detect hydrogen when it is in combination with other elements (i.e., H 2 O, OH, etc.). In this paper we discuss the use of ion beam techniques for obtaining quantitative depth information on hydrogen in materials and discuss the application of these techniques to several problems important in some of the areas mentioned

  19. Depth distribution of nitrogen in silicon from plasma ion implantation

    International Nuclear Information System (INIS)

    Vajo, J.J.; Williams, J.D.; Wei, R.; Wilson, R.G.; Matossian, J.N.

    1994-01-01

    Plasma Ion Implantation (PII) is an ion implantation technique that eliminates the line-of-sight restriction of conventional ion-beam implantation and therefore allows for cost effective surface modification of large-scale objects or large-number of small-scale objects. In PII, a part to be implanted is immersed in a low-pressure (10 -4 --10 -5 Torr), partially-ionized plasma that surrounds the part with a plasma sheath. The part is negatively pulse biased up to 100 keV using a repetitive train (100--1,000 Hz) of short-duration (10--40 μsec) voltage pulses. The applied voltage develops across the sheath and accelerates plasma ions into the surface, implanting them omnidirectionally and simultaneously over the entire surface of the part. The depth distribution of the implanted ions influences the extent and type of surface modification achieved and depends upon many factors. These include three rise and fall time of the voltage-pulse waveform, the voltage-pulse amplitude, the ion specie, the ion density, and the temperature of the target. Understanding the contributions to the depth distribution from each of these factors will enable prediction of conditions that will be useful for implantation of large complex parts. To investigate the contributions to the measured depth distributions from these factors nitrogen, predominantly as N + 2 , has been implanted into silicon using PII at 50 and 100 keV (25 and 50 keV per N atom). The implanted depth distributions have been determined using secondary ion mass spectroscopy and Auger electron spectroscopy depth profiling. The distributions differ from the typical, approximately Gaussian, profiles that result from conventional mass selected monoenergetic ion beam implantation. In comparison with ion beam implants and numerical simulations the profiles appear ''filled-in'' with an approximately constant nitrogen concentration for depths less than the expected average ion range

  20. Depth distribution of benthic dinoflagellates in the Caribbean Sea

    Science.gov (United States)

    Boisnoir, Aurélie; Pascal, Pierre-Yves; Cordonnier, Sébastien; Lemée, Rodolophe

    2018-05-01

    Monitoring of benthic dinoflagellates is usually conducted between sub-surface and 5 m depth, where these organisms are supposed to be in highest abundances. However, only few studies have focused on the small-scale depth distribution of benthic dinoflagellates. In the present study, abundances of dinoflagellates were evaluated on an invasive macrophyte Halophila stipulacea in two coastal sites in Guadeloupe (Caribbean Sea) along a depth gradient from sub-surface to 3 m at Gosier and until 20 m at Rivière Sens during the tropical wet and dry seasons. Species of genus Ostreopsis and Prorocentrum were the most abundant. Depth did not influence total dinoflagellate abundance but several genera showed particular depth-distribution preferences. The highest abundances of Ostreopsis and Gambierdiscus species were estimated preferentially in surface waters, whereas Coolia spp. were found in the same proportions but in deeper waters. Halophila stipulacea biomass was positively correlated with Ostreopsis spp. abundance. Our study suggests that sampling of benthic dinoflagellates should be conducted at different water depths taking into account the presence of the macroalgal substrate as well. In the Caribbean area, special attention should be addressed to the presence of H. stipulacea which tends to homogenize the marine landscape and represents a substrate for hosting dinoflagellate growth.

  1. Hydrogen in oxygen-free, phosphorus-doped copper - Charging techniques, hydrogen contents and modelling of hydrogen diffusion and depth profile

    Energy Technology Data Exchange (ETDEWEB)

    Martinsson, Aasa [Swerea KIMAB, Kista (Sweden); Sandstroem, Rolf [Swerea KIMAB, Kista (Sweden); Div. of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden); Lilja, Christina [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2013-01-15

    In Sweden spent nuclear fuel is planned to be disposed of by encapsulating in cast iron inserts protected by a copper shell. The copper can be exposed to hydrogen released during corrosion processes in the inserts. If the hydrogen is taken up by the copper, it could lead to hydrogen embrittlement. Specimens from oxygen-free copper have been hydrogen charged using two different methods. The purpose was to investigate how hydrogen could be introduced into copper in a controlled way. The thermal charging method resulted in a reduction of the initial hydrogen content. After electrochemical charging of cylindrical specimens, the measured hydrogen content was 2.6 wt. ppm which should compared with 0.6 wt. ppm before charging. The retained hydrogen after two weeks was reduced by nearly 40%. Recently the paper 'Hydrogen depth profile in phosphorus-doped, oxygen-free copper after cathodic charging' (Martinsson and Sandstrom, 2012) has been published. The paper describes experimental results for bulk specimens as well as presenting a model. Almost all the hydrogen is found to be located less than 100 {mu}m from the surface. This model is used to interpret the experimental results on foils in the present report. Since the model is fully based on fundamental equations, it can be used to analyse what happens in new situations. In this report the effect of the charging intensity, the grain size, the critical nucleus size for hydrogen bubble formation as well as the charging time are analysed.

  2. Hydrogen in oxygen-free, phosphorus-doped copper-Charging techniques, hydrogen contents and modelling of hydrogen diffusion and depth profile

    International Nuclear Information System (INIS)

    Martinsson, Aasa; Sandstroem, Rolf; Lilja, Christina

    2013-01-01

    In Sweden spent nuclear fuel is planned to be disposed of by encapsulating in cast iron inserts protected by a copper shell. The copper can be exposed to hydrogen released during corrosion processes in the inserts. If the hydrogen is taken up by the copper, it could lead to hydrogen embrittlement. Specimens from oxygen-free copper have been hydrogen charged using two different methods. The purpose was to investigate how hydrogen could be introduced into copper in a controlled way. The thermal charging method resulted in a reduction of the initial hydrogen content. After electrochemical charging of cylindrical specimens, the measured hydrogen content was 2.6 wt. ppm which should compared with 0.6 wt. ppm before charging. The retained hydrogen after two weeks was reduced by nearly 40%. Recently the paper 'Hydrogen depth profile in phosphorus-doped, oxygen-free copper after cathodic charging' (Martinsson and Sandstrom, 2012) has been published. The paper describes experimental results for bulk specimens as well as presenting a model. Almost all the hydrogen is found to be located less than 100 μm from the surface. This model is used to interpret the experimental results on foils in the present report. Since the model is fully based on fundamental equations, it can be used to analyse what happens in new situations. In this report the effect of the charging intensity, the grain size, the critical nucleus size for hydrogen bubble formation as well as the charging time are analysed

  3. Depth distribution of martensite in xenon implanted stainless steels

    International Nuclear Information System (INIS)

    Johansen, A.; Johnson, E.; Sarholt-Kristensen, L.; Steenstrup, S.; Hayashi, N.; Sakamoto, I.

    1989-01-01

    The amount of stress-induced martensite and its distribution in depth in xenon implanted austenitic stainless steel poly- and single crystals have been measured by Rutherford backscattering and channeling analysis, depth selective conversion electron Moessbauer spectroscopy, cross-sectional transmission electron microscopy and x-ray diffraction analysis. In low nickel 17/7, 304 and 316 commercial stainless steels and in 17:13 single crystals the martensitic transformation starts at the surface and develops towards greater depth with increasing xenon fluence. The implanted layer is nearly completely transformed, and the interface between martensite and austenite is rather sharp and well defined. In high nickel 310 commercial stainless steel and 15:19 and 20:19 single crystals, on the other hand, only insignificant amounts of martensite are observed. (orig.)

  4. Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids.

    Science.gov (United States)

    Nichols, S N; Hofmann, R W; Williams, W M; van Koten, C

    2016-05-20

    Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC 1 ) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Two white clover cultivars, two T. uniflorum accessions and two BC 1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100-200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC 1 than 'Crusader'. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50-100 mm deep than the other entries, and more of its fine root mass at 400-500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400-500 mm than most entries, and a smaller decrease in root length density with depth. These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Distribution of implanted hydrogen in amorphous silicon dioxide a-SiO2

    International Nuclear Information System (INIS)

    Mokrushin, A.D.; Agafonov, Yu.A.; Zinenko, V.I.; Pustovit, A.N.

    2004-01-01

    Hydrogen SIMS distributions are measured in quartz glasses implanted by different doses of H 2 + ions with energy 40 keV. There are two features in distributions: the availability of intensive peak close to the surface and near-constant dependence at large depth up to ions range. These peculiarities are perhaps attributable to the radiation induced diffusion of hydrogen atoms back to the surface via which ions are implanted [ru

  6. Momentum distribution at great depths when electron axial channeling

    International Nuclear Information System (INIS)

    Khokonov, M.Kh.; Tuguz, F.K.

    1989-01-01

    The electron distribution in momenta during axial channeling in thick monocrystals in great depths is estimated. The estimate was carried out with respect to the fact that due to diffusion the angular momentum of the electron can change only in a limited region of phase space and that multiple scattering only takes place on thermal oscillations of nuclei of the crystal lattice. It is shown that in thick monocrystals the distribution in momenta can be considered uniform on the greater part of the way of channeled electrons which can simplity the qualitative consideration of spectral-angular characteristics forming during this radiation

  7. Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis.

    Science.gov (United States)

    Wilde, Markus; Ohno, Satoshi; Ogura, Shohei; Fukutani, Katsuyuki; Matsuzaki, Hiroyuki

    2016-03-29

    Nuclear reaction analysis (NRA) via the resonant (1)H((15)N,αγ)(12)C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a (15)N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the (1)H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~10(13) cm(-2) (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~10(18) cm(-3) (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal (15)N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, (1)H((15)N,αγ)(12)C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of (15)N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

  8. Scaling and extrapolation of hydrogen distribution experiments

    International Nuclear Information System (INIS)

    Karwat, H.

    1986-01-01

    The containment plays an important role in predicting the residual risk to the environment under severe accident conditions. Risk analyses show that massive fission product release from the reactor fuel can occur only if during a loss of coolant the core is severely damaged and a containment failure is anticipated. Large amounts of hydrogen inevitably, are formed during the core degradation and will be released into the containment. More combustible gases are produced later when the coremelt will contact the containment concrete. Thus a potential for an early containment failure exists if a massive hydrogen deflagration cannot be excluded. A more remote cause for early containment failure may be an energetic steam explosion which requires a number of independent conditions when the molten core material contacts residual coolant water. The prediction of the containment loads caused by a hydrogen combustion is dependent on the prediction of the combustion mode. In the paper an attempt is made to identify on basis of a dimensional analysis such areas for which particular care must be exercised when scale experimental evidence is interpreted and extrapolated with the aid of a computer code or a system of computer codes. The study is restricted to fluid dynamic phenomena of the gas distribution process within the containment atmosphere. The gas sources and the mechanical response of containment structures are considered as given boundary conditions under which the containment is to be analyzed

  9. Depth distribution of multiple order X-ray scatter

    International Nuclear Information System (INIS)

    Yao Weiguang; Leszczynski, Konrad

    2008-01-01

    Scatter can significantly affect quality of projectional X-ray radiographs and tomographic reconstructions. With this in mind, we examined some of the physical properties of multiple orders of scatter of X-ray photons traversing through a layer of scattering media such as water. Using Monte Carlo techniques, we investigated depth distributions of interactions between incident X-ray photons and water before the resulting scattered photons reach the detector plane. Effects of factors such as radiation field size, air gap, thickness of the layer of scattering medium and X-ray energy, on the scatter were included in the scope of this study. The following scatter characteristics were observed: (1) for a layer of scattering material corresponding to the typical subject thickness in medical imaging, frequency distribution of locations of the last scattering interaction increases approximately exponentially with depth, and the higher the order of scatter or the energy of the incident photon, the narrower is the distribution; (2) for the second order scatter, the distribution of locations of the first interaction is more uniform than that of the last interaction and is dependent on the energy of the primary photons. Theoretical proofs for some of these properties are given. These properties are important to better understanding of effects of scatter on the radiographic and tomographic imaging process and to developing effective methods for scatter correction

  10. The Spatial Variability of Beryllium-7 Depth Distribution Study

    International Nuclear Information System (INIS)

    Jalal Sharib; Zainudin Othman; Dainee Nor Fardzila Ahmad Tugi; Noor Fadzilah Yusof; Mohd Tarmizi Ishak

    2015-01-01

    The objective of this paper is to study the spatial variability of 7 Be depth evolution in soil profile at two different sampling sites. The soil samples have been collected by using metal core in bare area in Bangi, Selangor and Timah Tasoh, Perlis , Malaysia. Two composite core samples for each sampling sites has been sectioned into 2 mm increments to a depth of 4 cm and oven dried at 45- 60 degree Celsius and gently desegregated. These two composite spatial samples are passed through a < 2 mm sieve and packed into proper geometry plastic container for 7 Be analysis by using gamma spectrometry with a 24-hour count time. From the findings, the 7 Be content in the soil samples from Bangi, Selangor study area is distributed lower depth penetration into the soil profile than Timah Tasoh, Perlis catchment due to many factors such as precipitation (fallout) and others. However, the spatial variability from both samples study area is also decreases exponentially with depth and is confined within the top few centimeters and similar with other works been reported (Blake et al., (2000) and Walling et al.,(2008). Furthermore, a detailed discussion from this study findings will be in full papers. (author)

  11. On depth profiling of hydrogen and helium isotopes and its application to ion-implantation studies

    International Nuclear Information System (INIS)

    Boettiger, J.

    1979-01-01

    The thesis is divided into two parts, the first being a general review of the experimental methods for depth profiling of light isotopes, where ion beams are used. In the second part, studies of ion implantation of hydrogen and helium isotopes, applying the techniques discussed in the first part, are described. The paper summarizes recent experimental results and discusses recent developments. (Auth.)

  12. Hybrid Hydrogen and Mechanical Distributed Energy Storage

    Directory of Open Access Journals (Sweden)

    Stefano Ubertini

    2017-12-01

    Full Text Available Effective energy storage technologies represent one of the key elements to solving the growing challenges of electrical energy supply of the 21st century. Several energy storage systems are available, from ones that are technologically mature to others still at a research stage. Each technology has its inherent limitations that make its use economically or practically feasible only for specific applications. The present paper aims at integrating hydrogen generation into compressed air energy storage systems to avoid natural gas combustion or thermal energy storage. A proper design of such a hybrid storage system could provide high roundtrip efficiencies together with enhanced flexibility thanks to the possibility of providing additional energy outputs (heat, cooling, and hydrogen as a fuel, in a distributed energy storage framework. Such a system could be directly connected to the power grid at the distribution level to reduce power and energy intermittence problems related to renewable energy generation. Similarly, it could be located close to the user (e.g., office buildings, commercial centers, industrial plants, hospitals, etc.. Finally, it could be integrated in decentralized energy generation systems to reduce the peak electricity demand charges and energy costs, to increase power generation efficiency, to enhance the security of electrical energy supply, and to facilitate the market penetration of small renewable energy systems. Different configurations have been investigated (simple hybrid storage system, regenerate system, multistage system demonstrating the compressed air and hydrogen storage systems effectiveness in improving energy source flexibility and efficiency, and possibly in reducing the costs of energy supply. Round-trip efficiency up to 65% can be easily reached. The analysis is conducted through a mixed theoretical-numerical approach, which allows the definition of the most relevant physical parameters affecting the system

  13. Depth profiling of hydrogen in ferritic/martensitic steels by means of a tritium imaging plate technique

    International Nuclear Information System (INIS)

    Otsuka, Teppei; Tanabe, Tetsuo

    2013-01-01

    Highlights: ► We applied a tritium imaging plate technique to depth profiling of hydrogen in bulk. ► Changes of hydrogen depth profiles in the steel by thermal annealing were examined. ► We proposed a release model of plasma-loaded hydrogen in the steel. ► Hydrogen is trapped at trapping sites newly developed by plasma loading. ► Hydrogen is also trapped at surface oxides and hardly desorbed by thermal annealing. -- Abstract: In order to understand how hydrogen loaded by plasma in F82H is removed by annealing at elevated temperatures in vacuum, depth profiles of plasma-loaded hydrogen were examined by means of a tritium imaging plate technique. Owing to large hydrogen diffusion coefficients in F82H, the plasma-loaded hydrogen easily penetrates into a deeper region becoming solute hydrogen and desorbs by thermal annealing in vacuum. However the plasma-loading creates new hydrogen trapping sites having larger trapping energy than that for the intrinsic sites beyond the projected range of the loaded hydrogen. Some surface oxides also trap an appreciable amount of hydrogen which is more difficult to remove by the thermal annealing

  14. Measurement system for depth dose distribution in cancer therapy

    International Nuclear Information System (INIS)

    Nishizawa, Hiroshi; Fujiwara, Hirotsugu; Tsutaka, Yoshikazu; Ikeda, Ikuo

    1999-01-01

    An accurate estimation of an absorbed dose distribution in human tissue is indispensable to efficiently perform radiotherapy in humans. Previously, various methods for such estimation have been developed, however, there is some problem in those methods, it takes too long times (3-4 hours) to determine the absorbed dose distribution through scanning by ionization chamber in water phantom. So, a determination system of depth dose was developed with an aim to determine the absorbed dose of X-ray or electron beam in materials similar to human body. This system was composed of a detector including scintillation fibers which allows emission due to radio-interaction, CCD camera for determination of light distribution of the emission and personal computer for data processing. Though the accuracy of this system was ±2% similar to that of the conventional measuring method, measuring time was reduced to almost 5 min, markedly shorter than that of the conventional water phantom (3-4 hours). The efficacy of works including the adjustment of irradiation system, planning, etc. would be improved by application of this system. (M.N.)

  15. Depth distributions of light action spectra for skin chromophores

    Science.gov (United States)

    Barun, V. V.; Ivanov, A. P.

    2010-03-01

    Light action spectra over wavelengths of 300-1000 nm are calculated for components of the human cutaneous covering: melanin, basal (bloodless) tissue, and blood oxy- and deoxyhemoglobin. The transformation of the spectra with depth in biological tissue results from two factors. The first is the wavelength dependence of the absorption coefficient corresponding to a particular skin chromophore and the second is the spectral selectivity of the radiation flux in biological tissue. This factor is related to the optical properties of all chromophores. A significant change is found to take place in the spectral distribution of absorbed radiant power with increasing depth. The action spectrum of light for the molecular oxygen contained in all components of biological tissue is also studied in the 625-645 nm range. The spectra are found to change with both the volume fraction of blood vessels and the degree of oxygenation of the blood. These results are useful for analyzing processes associated with optical absorption that are possible mechanisms for the interaction of light with biological tissues: photodissociation of oxyhemoglobin and the light-oxygen effect.

  16. Simulation of depth distribution of geological strata. HQSW program

    International Nuclear Information System (INIS)

    Czubek, J.A.; Kolakowski, L.

    1987-01-01

    The method of simulation of the layered geological formation for a given geological parameter is presented. The geological formation contains at least two types of layers and is given with the depth resolution Δh corresponding to the thickness of the hypothetical elementary layer. Two types of geostatistical distributions of the rock parameters are considered: modified normal and modified lognormal for which the input data are expected value and the variance. The HQSW simulation program given in the paper generates in a random way (but in a given repeatable sequence) the thicknesses of a given type of strata, their average specific radioactivity and the variance of specific radioactivity within a given layer. 8 refs., 14 figs., 1 tab. (author)

  17. Hydrogen Distribution in the Lunar Polar Regions

    Science.gov (United States)

    Sanin, A. B.; Mitrofanov, I. G.; Litvak, M. L.; Bakhtin, B. N.; Bodnarik, J. G.; Boynton, W. V.; Chin, G.; Evans, L. G.; Harshmann, K.; Fedosov, F.; hide

    2016-01-01

    We present a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top approximately 1 m layer of lunar regolith. Polar maps of the Moon’s inferred hydrogen abundance are presented and discussed.

  18. Hydrogen distribution in a containment with a high-velocity hydrogen-steam source

    International Nuclear Information System (INIS)

    Bloom, G.R.; Muhlestein, L.D.; Postma, A.K.; Claybrook, S.W.

    1982-09-01

    Hydrogen mixing and distribution tests are reported for a modeled high velocity hydrogen-steam release from a postulated small pipe break or release from a pressurizer relief tank rupture disk into the lower compartment of an Ice Condenser Plant. The tests, which in most cases used helium as a simulant for hydrogen, demonstrated that the lower compartment gas was well mixed for both hydrogen release conditions used. The gas concentration differences between any spatial locations were less than 3 volume percent during the hydrogen/steam release period and were reduced to less than 0.5 volume percent within 20 minutes after termination of the hydrogen source. The high velocity hydrogen/steam jet provided the dominant mixing mechanism; however, natural convection and forced air recirculation played important roles in providing a well mixed atmosphere following termination of the hydrogen source. 5 figures, 4 tables

  19. Simulation of hydrogen distribution in an Indian Nuclear Reactor Containment

    Energy Technology Data Exchange (ETDEWEB)

    Prabhudharwadkar, Deoras M. [Department of Mechanical Engineering, Indian Institute of Technology, Mumbai (India); Iyer, Kannan N., E-mail: kiyer@iitb.ac.i [Department of Mechanical Engineering, Indian Institute of Technology, Mumbai (India); Mohan, Nalini; Bajaj, Satinder S. [Nuclear Power Corporation of India Ltd., Mumbai (India); Markandeya, Suhas G. [Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    2011-03-15

    Research highlights: This work addresses hydrogen dispersion in commercial nuclear reactor containment. The numerical tool used for simulation is first benchmarked with experimental data. Parametric results are then carried out for different release configurations. Results lead to the conclusion that the dispersal is buoyancy dominated. Also, the hydrogen concentration is high enough to demand mitigation devices. - Abstract: The management of hydrogen in a Nuclear Reactor Containment after LOCA (Loss Of Coolant Accident) is of practical importance to preserve the structural integrity of the containment. This paper presents the results of systematic work carried out using the commercial Computational Fluid Dynamics (CFD) software FLUENT to assess the concentration distribution of hydrogen in a typical Indian Nuclear Reactor Containment. In order to obtain an accurate estimate of hydrogen concentration distribution, a suitable model for turbulence closure is required to be selected. Using guidelines from the previous studies reported in the literature and a comparative simulation study using simple benchmark problems, the most suitable turbulence model for hydrogen mixing prediction was identified. Subsequently, unstructured meshes were generated to represent the containment of a typical Indian Nuclear Reactor. Analyses were carried out to quantify the hydrogen distribution for three cases. These were (1) Uniform injection of hydrogen for a given period of time at room temperature, (2) Time varying injection as has been computed from an accident analysis code, (3) Time varying injection (as used in case (2)) at a high temperature. A parametric exercise was also carried out in case (1) where the effect of various inlet orientations and locations on hydrogen distribution was studied. The results indicate that the process of hydrogen dispersal is buoyancy dominated. Further for typical injection rates encountered following LOCA, the dispersal is quite poor and most

  20. Simulation of hydrogen distribution in an Indian Nuclear Reactor Containment

    International Nuclear Information System (INIS)

    Prabhudharwadkar, Deoras M.; Iyer, Kannan N.; Mohan, Nalini; Bajaj, Satinder S.; Markandeya, Suhas G.

    2011-01-01

    Research highlights: → This work addresses hydrogen dispersion in commercial nuclear reactor containment. → The numerical tool used for simulation is first benchmarked with experimental data. → Parametric results are then carried out for different release configurations. → Results lead to the conclusion that the dispersal is buoyancy dominated. → Also, the hydrogen concentration is high enough to demand mitigation devices. - Abstract: The management of hydrogen in a Nuclear Reactor Containment after LOCA (Loss Of Coolant Accident) is of practical importance to preserve the structural integrity of the containment. This paper presents the results of systematic work carried out using the commercial Computational Fluid Dynamics (CFD) software FLUENT to assess the concentration distribution of hydrogen in a typical Indian Nuclear Reactor Containment. In order to obtain an accurate estimate of hydrogen concentration distribution, a suitable model for turbulence closure is required to be selected. Using guidelines from the previous studies reported in the literature and a comparative simulation study using simple benchmark problems, the most suitable turbulence model for hydrogen mixing prediction was identified. Subsequently, unstructured meshes were generated to represent the containment of a typical Indian Nuclear Reactor. Analyses were carried out to quantify the hydrogen distribution for three cases. These were (1) Uniform injection of hydrogen for a given period of time at room temperature, (2) Time varying injection as has been computed from an accident analysis code, (3) Time varying injection (as used in case (2)) at a high temperature. A parametric exercise was also carried out in case (1) where the effect of various inlet orientations and locations on hydrogen distribution was studied. The results indicate that the process of hydrogen dispersal is buoyancy dominated. Further for typical injection rates encountered following LOCA, the dispersal is

  1. Redox Flow Batteries, Hydrogen and Distributed Storage.

    Science.gov (United States)

    Dennison, C R; Vrubel, Heron; Amstutz, Véronique; Peljo, Pekka; Toghill, Kathryn E; Girault, Hubert H

    2015-01-01

    Social, economic, and political pressures are causing a shift in the global energy mix, with a preference toward renewable energy sources. In order to realize widespread implementation of these resources, large-scale storage of renewable energy is needed. Among the proposed energy storage technologies, redox flow batteries offer many unique advantages. The primary limitation of these systems, however, is their limited energy density which necessitates very large installations. In order to enhance the energy storage capacity of these systems, we have developed a unique dual-circuit architecture which enables two levels of energy storage; first in the conventional electrolyte, and then through the formation of hydrogen. Moreover, we have begun a pilot-scale demonstration project to investigate the scalability and technical readiness of this approach. This combination of conventional energy storage and hydrogen production is well aligned with the current trajectory of modern energy and mobility infrastructure. The combination of these two means of energy storage enables the possibility of an energy economy dominated by renewable resources.

  2. Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

    Energy Technology Data Exchange (ETDEWEB)

    Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

    1997-12-31

    The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

  3. Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

    Energy Technology Data Exchange (ETDEWEB)

    Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

    1996-12-31

    The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

  4. An improved in situ method for determining depth distributions of gamma-ray emitting radionuclides

    International Nuclear Information System (INIS)

    Benke, R.R.; Kearfott, K.J.

    2001-01-01

    In situ gamma-ray spectrometry determines the quantities of radionuclides in some medium with a portable detector. The main limitation of in situ gamma-ray spectrometry lies in determining the depth distribution of radionuclides. This limitation is addressed by developing an improved in situ method for determining the depth distributions of gamma-ray emitting radionuclides in large area sources. This paper implements a unique collimator design with conventional radiation detection equipment. Cylindrically symmetric collimators were fabricated to allow only those gamma-rays emitted from a selected range of polar angles (measured off the detector axis) to be detected. Positioned with its axis normal to surface of the media, each collimator enables the detection of gamma-rays emitted from a different range of polar angles and preferential depths. Previous in situ methods require a priori knowledge of the depth distribution shape. However, the absolute method presented in this paper determines the depth distribution as a histogram and does not rely on such assumptions. Other advantages over previous in situ methods are that this method only requires a single gamma-ray emission, provides more detailed depth information, and offers a superior ability for characterizing complex depth distributions. Collimated spectrometer measurements of buried area sources demonstrated the ability of the method to yield accurate depth information. Based on the results of actual measurements, this method increases the potential of in situ gamma-ray spectrometry as an independent characterization tool in situations with unknown radionuclide depth distributions

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

    International Nuclear Information System (INIS)

    Bystrova, N.V.

    1989-01-01

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

  6. Microplastic Distribution at Different Sediment Depths in an Urban Estuary

    Directory of Open Access Journals (Sweden)

    Kathryn A. Willis

    2017-12-01

    Full Text Available As plastic production increases, so to do the threats from plastic pollution. Microplastics (defined as plastics <5 mm are a subset of marine debris about which we know less than we do of larger debris items, though they are potentially ubiquitous in the marine environment. To quantify the distribution and change in microplastic densities through time, we sampled sediment cores from an estuary in Tasmania, Australia. We hypothesized that the type, distribution and abundance of microplastics observed would be associated with increasing plastic production, coastal population growth, and proximity to urban water outflows and local hydrodynamics. Sediments ranging from the year 1744 to 2004 were sub-sampled from each core. We observed microplastics in every sample, with greater plastic frequencies found in the upper (more recent sediments. This time trend of microplastic accumulation matched that of global plastic production and coastal population growth. We observed that fibers were the most abundant type of microplastic in our samples. These fibers were present in sediments that settled prior to the presence of plastics in the environment. We propose a simple statistical model to estimate the level of contamination in our samples. We suggest that the current trend in the literature suggesting very high loads of fibers, particularly in remote locations such as the deep seafloor, may be largely due to contamination.

  7. Nuclear method for determination of nitrogen depth distributions in single seeds. [/sup 14/N tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Sundqvist, B; Gonczi, L; Koersner, I; Bergman, R; Lindh, U

    1974-01-01

    (d,p) reactions in /sup 14/N were used for probing single kernels of seed for nitrogen content and nitrogen depth distributions. Comparison with the Kjeldahl method was made on individual peas and beans. The results were found to be strongly correlated. The technique to obtain depth distributions of nitrogen was also used on high- and low-lysine varieties of barley for which large differences in nitrogen distributions were found.

  8. Positron depth profiling of the structural and electronic structure transformations of hydrogenated Mg-based thin films

    Science.gov (United States)

    Eijt, S. W. H.; Kind, R.; Singh, S.; Schut, H.; Legerstee, W. J.; Hendrikx, R. W. A.; Svetchnikov, V. L.; Westerwaal, R. J.; Dam, B.

    2009-02-01

    We report positron depth-profiling studies on the hydrogen sorption behavior and phase evolution of Mg-based thin films. We show that the main changes in the depth profiles resulting from the hydrogenation to the respective metal hydrides are related to a clear broadening in the observed electron momentum densities in both Mg and Mg2Ni films. This shows that positron annihilation methods are capable of monitoring these metal-to-insulator transitions, which form the basis for important applications of these types of films in switchable mirror devices and hydrogen sensors in a depth-sensitive manner. Besides, some of the positrons trap at the boundaries of columnar grains in the otherwise nearly vacancy-free Mg films. The combination of positron annihilation and x-ray diffraction further shows that hydrogen loading at elevated temperatures, in the range of 480-600 K, leads to a clear Pd-Mg alloy formation of the Pd catalyst cap layer. At the highest temperatures, the hydrogenation induces a partial delamination of the ˜5 nm thin capping layer, as sensitively monitored by positron depth profiling of the fraction of ortho-positronium formed at interface with the cap layer. The delamination effectively blocks the hydrogen cycling. In Mg-Si bilayers, we investigated the reactivity upon hydrogen loading and heat treatments near 480 K, which shows that Mg2Si formation is fast relative to MgH2. The combination of positron depth profiling and transmission electron microscopy shows that hydrogenation promotes a complete conversion to Mg2Si for this destabilized metal hydride system, while a partially unreacted, Mg-rich amorphous prelayer remains on top of Mg2Si after a single heat treatment in an inert gas environment. Thin film studies indicate that the difficulty of rehydrogenation of Mg2Si is not primarily the result from slow hydrogen dissociation at surfaces, but is likely hindered by the presence of a barrier for removal of Mg from the readily formed Mg2Si.

  9. Depth Distribution Of The Maxima Of Extensive Air Shower

    Science.gov (United States)

    Adams, J. H.; Howell, L. W.

    2003-01-01

    Observations of the extensive air showers from space can be free from interference by low altitude clouds and aerosols if the showers develop at a sufficiently high altitude. In this paper we explore the altitude distribution of shower maxima to determine the fraction of all showers that will reach their maxima at sufficient altitudes to avoid interference from these lower atmosphere phenomena. Typically the aerosols are confined within a planetary boundary layer that extends from only 2-3 km above the Earth's surface. Cloud top altitudes extend above 15 km but most are below 4 km. The results reported here show that more than 75% of the showers that will be observed by EUSO have maxima above the planetary boundary layer. The results also show that more than 50% of the showers that occur on cloudy days have their maxima above the cloud tops.

  10. Small scale temporal distribution of radiocesium in undisturbed coniferous forest soil: Radiocesium depth distribution profiles.

    Science.gov (United States)

    Teramage, Mengistu T; Onda, Yuichi; Kato, Hiroaki

    2016-04-01

    The depth distribution of pre-Fukushima and Fukushima-derived (137)Cs in undisturbed coniferous forest soil was investigated at four sampling dates from nine months to 18 months after the Fukushima nuclear power plant accident. The migration rate and short-term temporal variability among the sampling profiles were evaluated. Taking the time elapsed since the peak deposition of pre-Fukushima (137)Cs and the median depth of the peaks, its downward displacement rates ranged from 0.15 to 0.67 mm yr(-1) with a mean of 0.46 ± 0.25 mm yr(-1). On the other hand, in each examined profile considerable amount of the Fukushima-derived (137)Cs was found in the organic layer (51%-92%). At this moment, the effect of time-distance on the downward distribution of Fukushima-derived (137)Cs seems invisible as its large portion is still found in layers where organic matter is maximal. This indicates that organic matter seems the primary and preferential sorbent of radiocesium that could be associated with the physical blockage of the exchanging sites by organic-rich dusts that act as a buffer against downward propagation of radiocesium, implying radiocesium to be remained in the root zone for considerable time period. As a result, this soil section can be a potential source of radiation dose largely due to high radiocesium concentration coupled with its low density. Generally, such kind of information will be useful to establish a dynamic safety-focused decision support system to ease and assist management actions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, M A; El-Fiki, M A; Eissa, H M; Abdel-Hafez, A; Naguib, S H [National Institute of Standards, Cairo (Egypt)

    1996-03-01

    Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs.

  12. Survey on depth distribution of underground structures for consideration of human intrusion into TRU waste repository

    International Nuclear Information System (INIS)

    Sakamoto, Yoshiaki; Senoo, Muneaki; Sugimoto, Junichiro; Ohishi, Kiyotaka; Okishio, Masanori; Shimizu, Haruo.

    1996-01-01

    Depth distributions of some kinds of underground structure in Japan have been investigated to get an information about suitable depth of underground repository for TRU waste that is arising from reprocessing and MOX fuel fabrication plants. The underground structures investigated in this work were foundation pile of multistoried building, that of elevated expressway, that of JR shinkansen railway, tunnel of subway and wells. The major depth distribution of the underground structures except for the wells was in range from 30 to 50m, and their maximum depth was less than 100m. On the other hand, the 99% of wells was less than 300m in depth. Maximum depth of the other underground structures has been also investigated for a survey of the utilization of underground by artificial structures in Japan. (author)

  13. The Pearson IV distribution and its application to ion implanted depth profiles

    International Nuclear Information System (INIS)

    Wilson, R.G.

    1980-01-01

    The Pearson IV distribution system is analyzed to determine the regions of validity for the values of the moments that produce convex, concave, more pointed than Gaussian, and more flat-topped than Gaussian distributions; the limits beyond which no significant change in distribution is produced; and excluded regions. These regions are illustrated in a figure that can be used to facilitate the determination of the Pearson IV moments for experimental ion implanted depth distributions. Examples are given of Pearson IV distributions to illustrate the effects of the ranges of skewness, kurtosis, and standard deviation, for both more pointed and more flat-topped than Gaussian distributions. A procedure is described for matching experimental ion implanted depth distributions to computer plotted Pearson IV modified Gaussian distributions. A few experimental curves are given to illustrate the different types of Pearson IV curves, and accuracies of moments are discussed. (author)

  14. Texture side information generation for distributed coding of video-plus-depth

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Raket, Lars Lau; Zamarin, Marco

    2013-01-01

    We consider distributed video coding in a monoview video-plus-depth scenario, aiming at coding textures jointly with their corresponding depth stream. Distributed Video Coding (DVC) is a video coding paradigm in which the complexity is shifted from the encoder to the decoder. The Side Information...... components) is strongly correlated, so the additional depth information may be used to generate more accurate SI for the texture stream, increasing the efficiency of the system. In this paper we propose various methods for accurate texture SI generation, comparing them with other state-of-the-art solutions...

  15. A technique for determining the depth distribution of cavities in He+-irradiated nickel

    International Nuclear Information System (INIS)

    Fenske, G.; Das, S.K.; Kaminsky, M.

    1979-01-01

    The authors describe a technique for examining the depth distribution of the damage (i.e., dislocations, bubbles and voids) in 4 He + ion-irradiated nickel. One existing technique is to section the sample parallel to the direction of the incident beam and prepare thin foils suitable for TEM. This technique has been used only in a few instances because of the difficulty in sample preparation, but it has the advantage that the entire depth distribution of damage can be obtained from a single sample. The technique described by the present authors is a modification of this type of technique and allows one to observe the depth distribution of bubbles and of damage in very near surface regions (<0.2μm) with excellent depth resolution and a small (approximately 50 A) uncertainty in locating the irradiated surface. (Auth.)

  16. Depth-Dose and LET Distributions of Antiproton Beams in Various Target Materials

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Olsen, Sune; Petersen, Jørgen B.B.

    the annihilation process. Materials We have investigated the impact of substituting the target material on  the depth-dose distribution of pristine and  spread out antiproton beams using the FLUKA Monte Carlo transport program. Classical ICRP targets are compared to water phantoms. In addition, track average...... unrestricted LET is calculated for all configurations. Finally, we investigate which concentrations of gadolinium and boron are needed in a water target in order to observe a significant change in the antiproton depth-dose distribution.  Results Results indicate, that there is no significant change...... in the depth-dose distribution and average LET when substituting the materials. Adding boron and gadolinium up to concentrations of 1 per 1000 atoms to a water phantom, did not change the depth-dose profile nor the average LET. Conclusions  According to our FLUKA calculations, antiproton neutron capture...

  17. A distributed dynamic model of a monolith hydrogen membrane reactor

    International Nuclear Information System (INIS)

    Michelsen, Finn Are; Wilhelmsen, Øivind; Zhao, Lei; Aasen, Knut Ingvar

    2013-01-01

    Highlights: ► We model a rigorous distributed dynamic model for a HMR unit. ► The model includes enough complexity for steady-state and dynamic analysis. ► Simulations show that the model is non-linear within the normal operating range. ► The model is useful for studying and handling disturbances such as inlet changes and membrane leakage. - Abstract: This paper describes a distributed mechanistic dynamic model of a hydrogen membrane reformer unit (HMR) used for methane steam reforming. The model is based on a square channel monolith structure concept, where air flows adjacent to a mix of natural gas and water distributed in a chess pattern of channels. Combustion of hydrogen gives energy to the endothermic steam reforming reactions. The model is used for both steady state and dynamic analyses. It therefore needs to be computationally attractive, but still include enough complexity to study the important steady state and dynamic features of the process. Steady-state analysis of the model gives optimum for the steam to carbon and steam to oxygen ratios, where the conversion of methane is 92% and the hydrogen used as energy for the endothermic reactions is 28% at the nominal optimum. The dynamic analysis shows that non-linear control schemes may be necessary for satisfactory control performance

  18. Depth distribution of chemical phase concentration determined by grazing incidence X-ray diffraction

    International Nuclear Information System (INIS)

    Novak, P.; Ballo, P.; Dobrocka, E.; Vallo, M.; Lalinsky, T.

    2013-01-01

    Grazing incidence geometry is widely used in X-ray diffraction analysis of thin films. Penetration depth of radiation can be easily changed by an appropriate selection of the angle of incidence α that enables obtaining information from different depths of the sample. This depth can be decreased up to a nanometer scale by approaching the critical angle α_c for total external reflection. This method therefore provides an efficient tool for the analysis of depth distribution of various structural properties, such as the crystallite size, the amorphous fraction, stress or the concentration of chemical phase. However, absorption of the radiation can be characterized by an average attenuation coefficient μ a special care has to be paid to the last property. Variation of chemical phase concentration with depth usually results in depth dependence on the attenuation coefficient. In this contribution a method for determination of depth distribution of a chemical phase is outlined. The method correctly takes into account the depth variation of the attenuation coefficient. The method is tested on thin oxidized Ir layers. The aim of this paper is a comparison two simple model cases with the experimental results. (authors)

  19. Phase pupil functions for focal-depth enhancement derived from a Wigner distribution function.

    Science.gov (United States)

    Zalvidea, D; Sicre, E E

    1998-06-10

    A method for obtaining phase-retardation functions, which give rise to an increase of the image focal depth, is proposed. To this end, the Wigner distribution function corresponding to a specific aperture that has an associated small depth of focus in image space is conveniently sheared in the phase-space domain to generate a new Wigner distribution function. From this new function a more uniform on-axis image irradiance can be accomplished. This approach is illustrated by comparison of the imaging performance of both the derived phase function and a previously reported logarithmic phase distribution.

  20. Comparison of the depth distribution processes for 137Cs and 210Pbex in cultivated soils

    International Nuclear Information System (INIS)

    Zhang Yunqi; Zhang Xinbao; Long Yi; He Xiubin; Yu Xingxiu

    2012-01-01

    This paper focuses on the different processes of 137 Cs and 210 Pb ex depth distribution in cultivated soils. In view of their different fallout deposition processes, considering radionuclide will diffuse from the plough layer to the plough pan layer duo to the concentration gradient between the two layers, the 137 Cs and 210 Pb ex depth distribution processes were theoretically derived. Additionally, the theoretical derivation was verified by the measured 137 Cs and 210 Pb ex values in the soil core collected from wheat field in Fujianzhuang, Shanxi Province, China, and the 137 Cs and 210 Pb ex concentrations variation with depth in soils of the wheat field was explained rationally. The 137 Cs depth distribution state in cultivated soils will consistently vary with time due to 137 Cs continual decay and diffusion as an artificial radionuclide without sustainable fallout input since 1960s. In contrast, the 210 Pb ex depth distribution in cultivated soils will achieve steady state because of sustainable deposition of the naturally occurring 210 Pb ex fallout, and it can be concluded that the differences between the theoretical and the measured values, especially for 210 Pb ex , might be associated with the history of plough depth variation or LUCC. (authors)

  1. Effects of External Hydrogen on Hydrogen Transportation and Distribution Around the Fatigue Crack Tip in Type 304 Stainless Steel

    Science.gov (United States)

    Chen, Xingyang; Zhou, Chengshuang; Cai, Xiao; Zheng, Jinyang; Zhang, Lin

    2017-10-01

    The effects of external hydrogen on hydrogen transportation and distribution around the fatigue crack tip in type 304 stainless steel were investigated by using hydrogen microprint technique (HMT) and thermal desorption spectrometry. HMT results show that some silver particles induced by hydrogen release are located near the fatigue crack and more silver particles are concentrated around the crack tip, which indicates that hydrogen accumulates in the vicinity of the crack tip during the crack growth in hydrogen gas environment. Along with the crack propagation, strain-induced α' martensite forms around the crack tip and promotes hydrogen invasion into the matrix, which will cause the crack initiation and propagation at the austenite/ α' martensite interface. In addition, the hydrogen content in the vicinity of the crack tip is higher than that at the crack edge far away from the crack tip, which is related to the stress state and strain-induced α' martensite.

  2. Analysis of hydrogen content and distribution in hydrogen storage alloys using neutron radiography

    International Nuclear Information System (INIS)

    Sakaguchi, Hiroki; Hatakeyama, Keisuke; Satake, Yuichi; Esaka, Takao; Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

    2000-01-01

    Small amounts of hydrogen in hydrogen storage alloys, such as Mg 2 Ni, were detected using neutron radiography (NRG). Hydrogen concentrations in a hydrogenated solid solution were determined by this technique. Furthermore, we were able to obtain NRG images for an initial stage of hydrogen absorption in the hydrogen storage alloys. NRG would be a new measurement method to clarify the behavior of hydrogen in hydrogen storage alloys. (author)

  3. Distribution of base rock depth estimated from Rayleigh wave measurement by forced vibration tests

    International Nuclear Information System (INIS)

    Hiroshi Hibino; Toshiro Maeda; Chiaki Yoshimura; Yasuo Uchiyama

    2005-01-01

    This paper shows an application of Rayleigh wave methods to a real site, which was performed to determine spatial distribution of base rock depth from the ground surface. At a certain site in Sagami Plain in Japan, the base rock depth from surface is assumed to be distributed up to 10 m according to boring investigation. Possible accuracy of the base rock depth distribution has been needed for the pile design and construction. In order to measure Rayleigh wave phase velocity, forced vibration tests were conducted with a 500 N vertical shaker and linear arrays of three vertical sensors situated at several points in two zones around the edges of the site. Then, inversion analysis was carried out for soil profile by genetic algorithm, simulating measured Rayleigh wave phase velocity with the computed counterpart. Distribution of the base rock depth inverted from the analysis was consistent with the roughly estimated inclination of the base rock obtained from the boring tests, that is, the base rock is shallow around edge of the site and gradually inclines towards the center of the site. By the inversion analysis, the depth of base rock was determined as from 5 m to 6 m in the edge of the site, 10 m in the center of the site. The determined distribution of the base rock depth by this method showed good agreement on most of the points where boring investigation were performed. As a result, it was confirmed that the forced vibration tests on the ground by Rayleigh wave methods can be useful as the practical technique for estimating surface soil profiles to a depth of up to 10 m. (authors)

  4. Demonstration of a collimated in situ method for determining depth distributions using gamma-ray spectrometry

    CERN Document Server

    Benke, R R

    2002-01-01

    In situ gamma-ray spectrometry uses a portable detector to quantify radionuclides in materials. The main shortcoming of in situ gamma-ray spectrometry has been its inability to determine radionuclide depth distributions. Novel collimator designs were paired with a commercial in situ gamma-ray spectrometry system to overcome this limitation for large area sources. Positioned with their axes normal to the material surface, the cylindrically symmetric collimators limited the detection of un attenuated gamma-rays from a selected range of polar angles (measured off the detector axis). Although this approach does not alleviate the need for some knowledge of the gamma-ray attenuation characteristics of the materials being measured, the collimation method presented in this paper represents an absolute method that determines the depth distribution as a histogram, while other in situ methods require a priori knowledge of the depth distribution shape. Other advantages over previous in situ methods are that this method d...

  5. Plasma Temperature Determination of Hydrogen Containing High-Frequency Electrodeless Lamps by Intensity Distribution Measurements of Hydrogen Molecular Band

    OpenAIRE

    Gavare, Zanda; Revalde, Gita; Skudra, Atis

    2010-01-01

    The goal of the present work was the investigation of the possibility to use intensity distribution of the Q-branch lines of the hydrogen Fulcher-α diagonal band (d3Πu−→a3∑g+ electronic transition; Q-branch with v=v′=2) to determine the temperature of hydrogen containing high-frequency electrodeless lamps (HFEDLs). The values of the rotational temperatures have been obtained from the relative intensity distributions for hydrogen-helium and hydrogen-argon HFEDLs depending on the applied curren...

  6. Measurement of depth-dose distributions by means of the LiF-fluoroplastic thermoluminescent detectors

    International Nuclear Information System (INIS)

    Shaks, A.I.; Uryaev, I.A.; Trifonov, V.A.; Reshetnikova, L.V.

    1977-01-01

    Depth-dose distributions have been studied by means of thin-layer thermoluminescent detectors LiF-fluoroplast (8 mg/cm 2 ). Dosimetric characteristics of the detectors are described. They are: tissue-equivalence, dependence of sensitivity on the dose, dose rate and angle of incidence of radiation, and time-dependent storage, of the total light absorbed. Comparison of the results obtained with the measurements taken with an extrapolation chamber has demonstrated the possibility of measuring the depth-dose distributions by means of LiF-fluoroplast detectors

  7. A study on the hydrogen distributions in a containment for nuclear plant severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kweon Ha; Kim, Ju Youn; Bae, Kyung Hyo [The Korea Maritime Univ., Busan (Korea, Republic of)

    2012-10-15

    Hydrogen explosion has been considered as one of the major issues since Fukushima nuclear accident. The cause of the explosion has not been discovered, but it is clear that the explosion strongly depends on hydrogen distributions in a containment. In this study hydrogen distributions are calculated and analyzed in the containment of APR 1400(Advanced Power Reactor 1400)

  8. Probability distribution of pitting corrosion depth and rate in underground pipelines: A Monte Carlo study

    International Nuclear Information System (INIS)

    Caleyo, F.; Velazquez, J.C.; Valor, A.; Hallen, J.M.

    2009-01-01

    The probability distributions of external-corrosion pit depth and pit growth rate were investigated in underground pipelines using Monte Carlo simulations. The study combines a predictive pit growth model developed by the authors with the observed distributions of the model variables in a range of soils. Depending on the pipeline age, any of the three maximal extreme value distributions, i.e. Weibull, Frechet or Gumbel, can arise as the best fit to the pitting depth and rate data. The Frechet distribution best fits the corrosion data for long exposure periods. This can be explained by considering the long-term stabilization of the diffusion-controlled pit growth. The findings of the study provide reliability analysts with accurate information regarding the stochastic characteristics of the pitting damage in underground pipelines.

  9. Probability distribution of pitting corrosion depth and rate in underground pipelines: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Caleyo, F. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico)], E-mail: fcaleyo@gmail.com; Velazquez, J.C. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico); Valor, A. [Facultad de Fisica, Universidad de La Habana, San Lazaro y L, Vedado, 10400, La Habana (Cuba); Hallen, J.M. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico)

    2009-09-15

    The probability distributions of external-corrosion pit depth and pit growth rate were investigated in underground pipelines using Monte Carlo simulations. The study combines a predictive pit growth model developed by the authors with the observed distributions of the model variables in a range of soils. Depending on the pipeline age, any of the three maximal extreme value distributions, i.e. Weibull, Frechet or Gumbel, can arise as the best fit to the pitting depth and rate data. The Frechet distribution best fits the corrosion data for long exposure periods. This can be explained by considering the long-term stabilization of the diffusion-controlled pit growth. The findings of the study provide reliability analysts with accurate information regarding the stochastic characteristics of the pitting damage in underground pipelines.

  10. Study of time variation of terrestrial gamma radiation due to depth distribution of soil moisture content

    International Nuclear Information System (INIS)

    Yoshioka, Katsuhiro

    1994-01-01

    An empirical equation was deduced from studies of time variations of terrestrial gamma exposure rate and soil moisture content with depth distribution in the surface layer. It was definitely suggested that the variation of terrestrial gamma exposure rate is most strongly influenced by the change of soil moisture content at 5 cm depth. The seasonal variation with a relative maximum in early autumn and a relative minimum in early spring was clearly obtained in the consequence of long time measurements of terrestrial gamma exposure rate and degree of soil dryness. The diurnal change and phase difference due to the effect of depth were also obtained in the dynamic characteristics of soil moisture content at 3 different depths. From the comparison between measured terrestrial gamma exposure rate and that evaluated from soil moisture content using the empirical equation, it was seen that seasonal variations of the both agreed fairly well as a whole. (author)

  11. Quantitative analysis of oxygen depth distribution by means of deuteron reaction

    International Nuclear Information System (INIS)

    Dyumin, A.N.; Eremin, V.K.; Konnikov, S.G.

    1993-01-01

    Experimentally are investigated and realized possibilities for using the reaction for quantitative determination of the depth profiles of the oxygen distribution in HTSC structures in layers up to 10 4 A. It is concluded that in the near-surface layers when profiling the oxygen content is achieved the spatial resolution of 150 A

  12. Distributed multi-hypothesis coding of depth maps using texture motion information and optical flow

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Zamarin, Marco; Rakêt, Lars Lau

    2013-01-01

    Distributed Video Coding (DVC) is a video coding paradigm allowing a shift of complexity from the encoder to the decoder. Depth maps are images enabling the calculation of the distance of an object from the camera, which can be used in multiview coding in order to generate virtual views, but also...

  13. The calculation of electron depth-dose distributions in multilayer medium

    International Nuclear Information System (INIS)

    Wang Chuanshan; Xu Mengjie; Li Zhiliang; Feng Yongxiang; Li Panlin

    1989-01-01

    Energy deposition in multilayer medium and the depth dose distribution in the layers are studied. Based on semi-empirical calculation of electron energy absorption in matter with EDMULT program of Tabata and Ito, further work has been carried out to extend the computation to multilayer composite material. New program developed in this paper makes IBM-PC compatible with complicated electron dose calculations

  14. Measurement of moisture depth distribution in composite materials using positron lifetime technique

    International Nuclear Information System (INIS)

    Singh, J.J.; Holt, W.H.; Mock, W. Jr.; Mall, G.H.

    1980-01-01

    Fiber-reinforced resin matrix composites reportedly suffer significant degradation in their mechanical properties when exposed to hot, moist, environments for extended periods. Moisture weakens the fiber matrix bond as well as the matrix shear strength. An important factor in determining the extent of degradation is the depth distribution of moisture in the resin matrix. Despite the importance of measuring moisture distribution and its effects on composite material properties, not enough data are available on suitable nondestructive techniques for detecting and measuring moisture diffusion in organic composite materials. This paper addresses itself to the problem of measuring the moisture content of such materials, with special emphasis on its depth distribution, using positron lifetime technique

  15. Depth distribution of damage obtained by Rutherford backscattering combined with channeling

    International Nuclear Information System (INIS)

    Behrisch, R.; Roth, J.

    1976-01-01

    The different approaches to determine depth distributions of damage in solids by Rutherford backscattering combined with channeling are reviewed. These methods are best applicable for damage introduced by ion bombardment. Most investigations up to now have been done at semiconductors where the ion damage seems to be more suited for analysis by this method than the ion damage in metals. The quantity used for getting depth profiles is mostly the increase in minimum yields in single alignment Rutherford backscattering, while only few measurements have been done at double alignment and at slight misalignment, i.e., the sides of the channeling dips

  16. The depth distribution of bubbles and fracture in He+ and D+ irradiated copper

    International Nuclear Information System (INIS)

    Johnson, P.B.; Mazey, D.J.

    1982-01-01

    Transmission electron microscopy is used to investigate the spatial arrangement and distribution with depth of gas bubbles produced in Cu by irradiation at 320 K to a level approx. equal to 4 x 10 21 30 keV He + m -2 . At the depth of maximum bubble size the bubbles are random and large (up to approx. equal to 10 nm across). At both shallower and greater depths the gas bubbles are smaller (approx. equal to 2 nm diam), much more uniform in size and ordered on an fcc superlattice with a lattice constant of a 1 approx. equal to 7.7 nm which (in contrast to the average bubble size) is independent of depth. It is suggested that blistering results from fracture, at a depth near the mean projected range, between large randomly-ordered bubbles which have evolved from smaller bubbles of uniform size arranged on a superlattice. For the particular case of D + irradiation of Cu at 120 K evidence is found to suggest that the fracture mechanisms involved in blistering and flaking are quite different. (orig.)

  17. A method for exploring the distribution of radioelements at depth using gamma-ray spectrometric data

    International Nuclear Information System (INIS)

    Li Qingyang

    1997-01-01

    Based on the inherent relation between radioelements and terrestrial heat flow, theoretically shows the possibility of exploring the distribution of radioelements at depth using gamma-ray spectrometric data, and a data-processing and synthesizing method has been adopted to deduce the calculation formula. The practical application in the uranium mineralized area No. 2801 in Yunnan Province proves that this method is of practical value, and it has been successfully applied to the data processing and good results have been obtained

  18. Plasma Temperature Determination of Hydrogen Containing High-Frequency Electrode less Lamps by Intensity Distribution Measurements of Hydrogen Molecular Band

    International Nuclear Information System (INIS)

    Gavare, Z.; Revalde, G.; Skudra, A.

    2011-01-01

    The goal of the present work was the investigation of the possibility to use intensity distribution of the Q-branch lines of the hydrogen Fulcher-a diagonal band (d3η u- a3Σg + electronic transition; Q-branch with ν=ν=2) to determine the temperature of hydrogen containing high-frequency electrode less lamps (HFEDLs). The values of the rotational temperatures have been obtained from the relative intensity distributions for hydrogen-helium and hydrogen-argon HFEDLs depending on the applied current. The results have been compared with the method of temperature derivation from Doppler profiles of He 667.8 nm and Ar 772.4 nm lines. The results of both methods are in good agreement, showing that the method of gas temperature determination from the intensity distribution in the hydrogen Fulcher-a (2-2)Q band can be used for the hydrogen containing HFEDLs. It was observed that the admixture of 10% hydrogen in the argon HFEDLs significantly reduces the gas temperature

  19. Correlation between hypocenter depth, antecedent precipitation and earthquake-induced landslide spatial distribution

    Science.gov (United States)

    Fukuoka, Hiroshi; Watanabe, Eisuke

    2017-04-01

    Since Keefer published the paper on earthquake magnitude and affected area, maximum epicentral/fault distance of induced landslide distribution in 1984, showing the envelope of plots, a lot of studies on this topic have been conducted. It has been generally supposed that landslides have been triggered by shallow quakes and more landslides are likely to occur with heavy rainfalls immediately before the quake. In order to confirm this, we have collected 22 case records of earthquake-induced landslide distribution in Japan and examined the effect of hypocenter depth and antecedent precipitation. Earthquake magnitude by JMA (Japan Meteorological Agency) of the cases are from 4.5 to 9.0. Analysis on hycpocenter depth showed the deeper quake cause wider distribution. Antecedent precipitation was evaluated using the Soil Water Index (SWI), which was developed by JMA for issuing landslide alert. We could not find meaningful correlation between SWI and the earthquake-induced landslide distribution. Additionally, we found that smaller minimum size of collected landslides results in wider distribution especially between 1,000 to 100,000 m2.

  20. Hydrogen generation, distribution and combustion under severe LWR accident conditions: a state-of-technology report

    International Nuclear Information System (INIS)

    Postma, A.K.; Hilliard, R.K.

    1983-03-01

    This report reviews the current state of technology regarding hydrogen safety issues in light water reactor plants. Topics considered in this report include hydrogen generation, distribution in containment, and combustion characteristics. A companion report addresses hydrogen control. The objectives of the study were to identify the key safety issues related to hydrogen produced under severe accident conditions, to describe the state of technology for each issue, and to point out ongoing programs aimed at resolving the open issues

  1. Distribution and depth of bottom-simulating reflectors in the Nankai subduction margin

    Science.gov (United States)

    Ohde, Akihiro; Otsuka, Hironori; Kioka, Arata; Ashi, Juichiro

    2018-04-01

    Surface heat flow has been observed to be highly variable in the Nankai subduction margin. This study presents an investigation of local anomalies in surface heat flows on the undulating seafloor in the Nankai subduction margin. We estimate the heat flows from bottom-simulating reflectors (BSRs) marking the lower boundaries of the methane hydrate stability zone and evaluate topographic effects on heat flow via two-dimensional thermal modeling. BSRs have been used to estimate heat flows based on the known stability characteristics of methane hydrates under low-temperature and high-pressure conditions. First, we generate an extensive map of the distribution and subseafloor depths of the BSRs in the Nankai subduction margin. We confirm that BSRs exist at the toe of the accretionary prism and the trough floor of the offshore Tokai region, where BSRs had previously been thought to be absent. Second, we calculate the BSR-derived heat flow and evaluate the associated errors. We conclude that the total uncertainty of the BSR-derived heat flow should be within 25%, considering allowable ranges in the P-wave velocity, which influences the time-to-depth conversion of the BSR position in seismic images, the resultant geothermal gradient, and thermal resistance. Finally, we model a two-dimensional thermal structure by comparing the temperatures at the observed BSR depths with the calculated temperatures at the same depths. The thermal modeling reveals that most local variations in BSR depth over the undulating seafloor can be explained by topographic effects. Those areas that cannot be explained by topographic effects can be mainly attributed to advective fluid flow, regional rapid sedimentation, or erosion. Our spatial distribution of heat flow data provides indispensable basic data for numerical studies of subduction zone modeling to evaluate margin parallel age dependencies of subducting plates.[Figure not available: see fulltext.

  2. Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

    Science.gov (United States)

    Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

    2005-12-01

    Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

  3. Cumulative history recorded in the depth distribution of radiocesium in sediments deposited on a sandbar

    International Nuclear Information System (INIS)

    Tanaka, Kazuya; Kondo, Hiroaki; Sakaguchi, Aya; Takahashi, Yoshio

    2015-01-01

    We collected sediments deposited on a sandbar from the surface to 20 cm in depth in the Abukuma River to clarify the history of radiocesium derived from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. We analyzed the "1"3"7Cs concentration in the sediments from size-fractioned samples as well as bulk samples. The depth distribution of "1"3"7Cs showed the highest concentration in the deepest sediment layer (18–20 cm) studied, which indicates that sediments with a lower "1"3"7Cs concentration were transported and deposited on sediments having a higher "1"3"7Cs concentration. At the same time, the depth distribution suggests a decrease in radioactivity in provenance areas of the sediments. Analysis of the size-fractioned sediments indicated that the three sediment layers at 4–6 cm, 16–18 cm and 18–20 cm intervals had similar size distribution of "1"3"7Cs and grain size composition although the concentration levels of "1"3"7Cs were different according to their bulk concentrations. The size distribution of "1"3"7Cs also supported the possibility that the decrease in "1"3"7Cs concentration in bulk sediments above 18 cm is due to a decrease in the level of radioactivity in the catchment area. A comparison of the size distribution of "1"3"7Cs between the sediment layers above and below 18 cm suggested that the "1"3"7Cs concentration in the transported fine sediment particles decreased more with time than the "1"3"7Cs concentration in the coarse particles, reflecting the selective transport of the finer particles. The results of this study demonstrated that sediment layers deposited on a sandbar retained the cumulative history of the fluvial transport of radiocesium after the FDNPP accident. - Highlights: • We investigated the history of "1"3"7Cs recorded in sediments in the Abukuma River. • "1"3"7Cs concentration was the highest in the deepest sediment layer studied. • The depth distribution suggests a decrease in radioactivity in

  4. Depth distribution of 2-keV helium-ion irradiation-induced cavities in nickel

    International Nuclear Information System (INIS)

    Fenske, G.; Das, S.K.; Kaminsky, M.

    1981-01-01

    Transmission electron microscopy has been used to study the effect of total dose on the depth distribution of cavities (voids or bubbles) in nickel irradiated at 500 0 C with 20-keV 4 He + ions. A transverse sectioning technique allowed us to obtain the entire depth distribution of cavities from a single specimen. The diameter, number density and volume fraction of cavities were measured as a function of depth from micrographs taken from samples sectioned parallel to the direction of the incident beam. Results for the doses at 2.9 x 10 15 and 2.9 x 10 16 ions/cm 2 show an increase in the average cavity diameter, number density and volume fraction with increasing dose. A further increase in dose from 2.9 x 10 16 to 2.9 x 10 17 ions/cm 2 also shows an increase in the average cavity diameter but a decrease in the number density. This observation is interpreted as evidence for the coalescence of cavities. 3 figures, 1 table

  5. Spatial distributions of dose enhancement around a gold nanoparticle at several depths of proton Bragg peak

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jihun [Department of Radiation Oncology, Hokkaido University Graduate School of Medicine, Hokkaido University (Japan); Sutherland, Kenneth [Department of Medical Physics, Hokkaido University Graduate School of Medicine, Hokkaido University (Japan); Hashimoto, Takayuki [Department of Radiation Medicine, Hokkaido University Graduate School of Medicine (Japan); Shirato, Hiroki [Department of Radiation Medicine, Hokkaido University Graduate School of Medicine and Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University (Japan); Date, Hiroyuki, E-mail: date@hs.hokudai.ac.jp [Faculty of Health Sciences, Hokkaido University (Japan)

    2016-10-01

    Gold nanoparticles (GNPs) have been recognized as a promising candidate for a radiation sensitizer. A proton beam incident on a GNP can produce secondary electrons, resulting in an enhancement of the dose around the GNP. However, little is known about the spatial distribution of dose enhancement around the GNP, especially in the direction along the incident proton. The purpose of this study is to determine the spatial distribution of dose enhancement by taking the incident direction into account. Two steps of calculation were conducted using the Geant4 Monte Carlo simulation toolkit. First, the energy spectra of 100 and 195 MeV protons colliding with a GNP were calculated at the Bragg peak and three other depths around the peak in liquid water. Second, the GNP was bombarded by protons with the obtained energy spectra. Radial dose distributions were computed along the incident beam direction. The spatial distributions of the dose enhancement factor (DEF) and subtracted dose (D{sub sub}) were then evaluated. The spatial DEF distributions showed hot spots in the distal radial region from the proton beam axis. The spatial D{sub sub} distribution isotropically spread out around the GNP. Low energy protons caused higher and wider dose enhancement. The macroscopic dose enhancement in clinical applications was also evaluated. The results suggest that the consideration of the spatial distribution of GNPs in treatment planning will maximize the potential of GNPs.

  6. Representing distributed cognition in complex systems: how a submarine returns to periscope depth.

    Science.gov (United States)

    Stanton, Neville A

    2014-01-01

    This paper presents the Event Analysis of Systemic Teamwork (EAST) method as a means of modelling distributed cognition in systems. The method comprises three network models (i.e. task, social and information) and their combination. This method was applied to the interactions between the sound room and control room in a submarine, following the activities of returning the submarine to periscope depth. This paper demonstrates three main developments in EAST. First, building the network models directly, without reference to the intervening methods. Second, the application of analysis metrics to all three networks. Third, the combination of the aforementioned networks in different ways to gain a broader understanding of the distributed cognition. Analyses have shown that EAST can be used to gain both qualitative and quantitative insights into distributed cognition. Future research should focus on the analyses of network resilience and modelling alternative versions of a system.

  7. Aerosol Optical Depth Distribution in Extratropical Cyclones over the Northern Hemisphere Oceans

    Science.gov (United States)

    Naud, Catherine M.; Posselt, Derek J.; van den Heever, Susan C.

    2016-01-01

    Using Moderate Resolution Imaging Spectroradiometer and an extratropical cyclone database,the climatological distribution of aerosol optical depth (AOD) in extratropical cyclones is explored based solely on observations. Cyclone-centered composites of aerosol optical depth are constructed for the Northern Hemisphere mid-latitude ocean regions, and their seasonal variations are examined. These composites are found to be qualitatively stable when the impact of clouds and surface insolation or brightness is tested. The larger AODs occur in spring and summer and are preferentially found in the warm frontal and in the post-cold frontal regions in all seasons. The fine mode aerosols dominate the cold sector AODs, but the coarse mode aerosols display large AODs in the warm sector. These differences between the aerosol modes are related to the varying source regions of the aerosols and could potentially have different impacts on cloud and precipitation within the cyclones.

  8. Post- and interseismic deformation due to both localized and distributed creep at depth (Invited)

    Science.gov (United States)

    Hetland, E. A.; Zhang, G.; Hines, T.

    2013-12-01

    There are two end-member representations of the ductile lithosphere (i.e., the lower crust and uppermost mantle) commonly used in models of post- and interseismic deformation around strike-slip faults: either (1) laterally homogeneous ductile layers, with sharp contrasts in rheological properties between the layers, in which creep is distributed; or (2) discrete extensions of the fault at depth in which creep is fully localized. The most realistic representation of the ductile lithosphere on earthquake cycle time scales likely falls between these two end-members. Researchers have considered both distributed and localized creep when interpreting post- and interseismic deformation, although the two mechanisms are most commonly treated separately, with the localized creep often approximated by kinematic slip on planar faults. There are a few noteworthy models that considered the feedback between both distributed and localized creep, although those models were largely constrained to 2D geometries of infinite length faults. The thickness of shear zones in the ductile lithosphere may be comparable to the locking depth of the fault, and the existence of a deep shear zone does not preclude the possibility that some distributed creep occurs in the surrounding lithosphere. Furthermore, variations in rheology, including both rheological models and their parameters, may be more subtle than the discrete contrasts typically assumed. In this presentation, we consider models of postseismic deformation following a finite length, strike-slip fault, as well as models of interseismic deformation around an infinite length strike-slip fault. Both sets of models are capable of localized and distributed creep at depth, and use Maxwell viscoelasticity. We show that the horizontal surface velocities during the early postseismic period are most sensitive to the viscosity of the shear zone; however during much of the interseismic period the shear zone is not apparent from the surface

  9. Hydrogen concentration and distribution in high-purity germanium crystals

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.; Luke, P.N.

    1981-10-01

    High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from a melt contained in a high-purity silica crucible. The benefits and problems encountered in using a hydrogen ambient are reviewed. A hydrogen concentration of about 2 x 10 15 cm -3 has been determined by growing crystals in hydrogen spiked with tritium and counting the tritium β-decays in detectors made from these crystals. Annealing studies show that the hydrogen is strongly bound, either to defects or as H 2 with a dissociation energy > 3 eV. This is lowered to 1.8 eV when copper is present. Etching defects in dislocation-free crystals grown in hydrogen have been found by etch stripping to have a density of about 1 x 10 7 cm -3 and are estimated to contain 10 8 H atoms each

  10. Data assimilation of depth-distributed satellite chlorophyll-α in two Mediterranean contrasting sites

    KAUST Repository

    Kalaroni, S.

    2016-04-12

    A new approach for processing the remote sensing chlorophyll-α (Chl-α) before assimilating into an ecosystem model is applied in two contrasting, regarding productivity and nutrients availability, Mediterranean sites: the DYFAMED and POSEIDON E1-M3A fixed point open ocean observatories. The new approach derives optically weighted depth-distributed Chl-α profiles from satellite data based on the model simulated Chl-α vertical distribution and light attenuation coefficient. We use the 1D version of the operational ecological 3D POSEIDON model, based on the European Regional Seas Ecosystem Model (ERSEM). The required hydrodynamic properties are obtained (off-line) from the POSEIDON operational 3D hydrodynamic Mediterranean basin scale model. The data assimilation scheme is the Singular Evolutive Interpolated Kalman (SEIK) filter, the ensemble variant of the Singular Evolutive Extended Kalman (SEEK) filter. The performance of the proposed assimilation approach was evaluated against the Chl-α satellite data and the seasonal averages of available in-situ data for nitrate, phosphate and Chl-α. An improvement of the model simulated near-surface and subsurface maximum Chl-α concentrations is obtained, especially at the DYFAMED site. Model nitrate is improved with assimilation, particularly with the new approach assimilating depth-distributed Chl-α, while model phosphate is slightly worse after assimilation. Additional sensitivity experiments were performed, showing a better performance of the new approach under different scenarios of model Chl-α deviation from pseudo-observations of surface Chl-α.

  11. Data assimilation of depth-distributed satellite chlorophyll-α in two Mediterranean contrasting sites

    KAUST Repository

    Kalaroni, S.; Tsiaras, K.; Petihakis, G.; Hoteit, Ibrahim; Economou-Amilli, A.; G.Triantafyllou

    2016-01-01

    A new approach for processing the remote sensing chlorophyll-α (Chl-α) before assimilating into an ecosystem model is applied in two contrasting, regarding productivity and nutrients availability, Mediterranean sites: the DYFAMED and POSEIDON E1-M3A fixed point open ocean observatories. The new approach derives optically weighted depth-distributed Chl-α profiles from satellite data based on the model simulated Chl-α vertical distribution and light attenuation coefficient. We use the 1D version of the operational ecological 3D POSEIDON model, based on the European Regional Seas Ecosystem Model (ERSEM). The required hydrodynamic properties are obtained (off-line) from the POSEIDON operational 3D hydrodynamic Mediterranean basin scale model. The data assimilation scheme is the Singular Evolutive Interpolated Kalman (SEIK) filter, the ensemble variant of the Singular Evolutive Extended Kalman (SEEK) filter. The performance of the proposed assimilation approach was evaluated against the Chl-α satellite data and the seasonal averages of available in-situ data for nitrate, phosphate and Chl-α. An improvement of the model simulated near-surface and subsurface maximum Chl-α concentrations is obtained, especially at the DYFAMED site. Model nitrate is improved with assimilation, particularly with the new approach assimilating depth-distributed Chl-α, while model phosphate is slightly worse after assimilation. Additional sensitivity experiments were performed, showing a better performance of the new approach under different scenarios of model Chl-α deviation from pseudo-observations of surface Chl-α.

  12. Shallow moonquakes - Depth, distribution and implications as to the present state of the lunar interior

    Science.gov (United States)

    Nakamura, Y.; Latham, G. V.; Dorman, H. J.; Ibrahim, A.-B. K.; Koyama, J.; Horvath, P.

    1979-01-01

    The observed seismic amplitudes of HFT (high-frequency teleseismic) events do not vary with distance as expected for surface sources, but are consistent with sources in the upper mantle of the moon. Thus, the upper mantle of the moon is the only zone where tectonic stresses deriving from differential thermal contraction and expansion of the lunar interior are presently high enough to cause moonquakes. The distribution of shallow moonquake epicenters suggests a possible correlation with impact basins, implying a lasting tectonic influence of impact basins long after their formation. The finite depths now assigned to these shallow moonquakes necessitate further revision to the seismic structural model of the lunar interior.

  13. Emission Depth Distribution Function of Al 2s Photoelectrons in Al2O3

    Science.gov (United States)

    Hucek, S.; Zemek, J.; Jablonski, A.; Tilinin, I. S.

    The escape probability of Al 2s photoelectrons leaving an aluminum oxide sample (Al2O3) has been studied as a function of depth of origin. It has been found that the escape probability (the so-called emission depth distribution function - DDF) depends strongly on the photoelectron emission direction with respect to that of the incident X-ray beam. In particular, in the emission direction close to that of photon propagation, the DDF differs substantially from the simple Beer-Lambert law and exhibits a nonmonotonic behavior with a maximum in the near-surface region at a depth of about 10 Å. Experimental results are in good agreement with theoretical predictions based on Monte Carlo simulations of the electron transport and with analytical solution of the linearized Boltzmann kinetic equation with appropriate boundary conditions. Both theoretical approaches take into account multiple elastic scattering of photoelectrons on their way out of the sample. It is shown that the commonly used straight line approximation (SLA), which neglects elastic scattering effects, fails to describe adequately experimental data at emission directions close to minima of the differential photoelectric cross section.

  14. Depth distribution of damage in copper irradiated with MeV, Ni and He ions

    International Nuclear Information System (INIS)

    Narayan, J.; Noggle, T.S.; Oen, O.S.

    1975-01-01

    Transmission electron microscopy was used to study radiation damage as a function of depth caused by 58 and 4-MeV 58 Ni and 1-MeV He ions in copper single crystals at ambient temperature. The experimental damage density vs penetration depth distributions were compared with calculations based on the atomic collision theory of Lindhard et al. (LSS). For 58-MeV Ni ions, the calculated damage profile using the theoretical LSS value of the electronic stopping parameter (k = 0.167) agrees well with experiment. However, for 4-MeV Ni ions it is necessary to use k = 0.12 to get agreement with the experimental data. In the case of 1-MeV He, the depth location of the calculated damage peak is in good agreement with experiment when the electronic stopping determined by Chu and Powers is used whereas it is about 15 percent too close to the surface using the tables of Northcliffe and Schilling. (auth)

  15. Comment on "Wigner phase-space distribution function for the hydrogen atom"

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Springborg, Michael

    1999-01-01

    We object to the proposal that the mapping of the three-dimensional hydrogen atom into a four-dimensional harmonic oscillator can be readily used to determine the Wigner phase-space distribution function for the hydrogen atom. [S1050-2947(99)07005-5].......We object to the proposal that the mapping of the three-dimensional hydrogen atom into a four-dimensional harmonic oscillator can be readily used to determine the Wigner phase-space distribution function for the hydrogen atom. [S1050-2947(99)07005-5]....

  16. Quantifying spatial distribution of snow depth errors from LiDAR using Random Forests

    Science.gov (United States)

    Tinkham, W.; Smith, A. M.; Marshall, H.; Link, T. E.; Falkowski, M. J.; Winstral, A. H.

    2013-12-01

    There is increasing need to characterize the distribution of snow in complex terrain using remote sensing approaches, especially in isolated mountainous regions that are often water-limited, the principal source of terrestrial freshwater, and sensitive to climatic shifts and variations. We apply intensive topographic surveys, multi-temporal LiDAR, and Random Forest modeling to quantify snow volume and characterize associated errors across seven land cover types in a semi-arid mountainous catchment at a 1 and 4 m spatial resolution. The LiDAR-based estimates of both snow-off surface topology and snow depths were validated against ground-based measurements across the catchment. Comparison of LiDAR-derived snow depths to manual snow depth surveys revealed that LiDAR based estimates were more accurate in areas of low lying vegetation such as shrubs (RMSE = 0.14 m) as compared to areas consisting of tree cover (RMSE = 0.20-0.35 m). The highest errors were found along the edge of conifer forests (RMSE = 0.35 m), however a second conifer transect outside the catchment had much lower errors (RMSE = 0.21 m). This difference is attributed to the wind exposure of the first site that led to highly variable snow depths at short spatial distances. The Random Forest modeled errors deviated from the field measured errors with a RMSE of 0.09-0.34 m across the different cover types. Results show that snow drifts, which are important for maintaining spring and summer stream flows and establishing and sustaining water-limited plant species, contained 30 × 5-6% of the snow volume while only occupying 10% of the catchment area similar to findings by prior physically-based modeling approaches. This study demonstrates the potential utility of combining multi-temporal LiDAR with Random Forest modeling to quantify the distribution of snow depth with a reasonable degree of accuracy. Future work could explore the utility of Terrestrial LiDAR Scanners to produce validation of snow-on surface

  17. Phantom experiment of depth-dose distributions for gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Matsumoto, T.; Kato, K.; Sakuma, Y.; Tsuruno, A.; Matsubayashi, M.

    1993-01-01

    Depth-dose distributions in a tumor simulated phantom were measured for thermal neutron flux, capture gamma-ray and internal conversion electron dose rates for gadolinium neutron capture therapy. The results show that (i) a significant dose enhancement can be achieved in the tumor by capture gamma-rays and internal conversion electrons but the dose is mainly due to capture gamma-rays from the Gd(n, γ) reactions, therefore, is not selective at the cellular level, (ii) the dose distribution was a function of strongly interrelated parameters such as gadolinium concentrations, tumor site and neutron beam size (collimator aperture size), and (iii) the Gd-NCT by thermal neutrons appears to be a potential for treatment of superficial tumor. (author)

  18. Determination of distribution function of refraction index and anion diffusion depth in porous alumina photonic crystals

    Directory of Open Access Journals (Sweden)

    H. Kaviani

    2007-09-01

    Full Text Available   Band structure of porous alumina photonic crystal in the Γ X direction was calculated using order-N method . In a comparison of calculated results with experimental data of reflective and absorptive index, the variation of refractive index of alumina in the external region of oxide layer, around the pores were studied. A Gaussian distribution function was adopted for phosphate anions in the external oxide layer and the variation of refractive index and diffusion depth were determined. The structure of the first four bands was calculated using the obtained distribution of refractive index in the external oxide layer for both TE and TM mode. This results show a narrow full band gap in the TM mode.

  19. Particle and solution phase depth distributions of transuranics and 55Fe in the North Pacific

    International Nuclear Information System (INIS)

    Livingston, H.D.; Mann, D.R.; Casso, S.A.; Schneider, D.L.; Surprenant, L.D.; Bowen, V.T.

    1987-01-01

    In situ large volume filtration and chemisorption techniques were used to collect samples from the North Pacific for radiochemical analyses of fallout transuranics and 55 Fe in filterable and filtered phases. The data cover several locations for surface collections and a detailed depth profile north of Hawaii at 30 0 N. The observed partition of these nuclides between suspended particulate and filtered phases is directly linked to the rates at which they are moved downward through the water column in association with sinking particles. Particulate phases in open ocean surface waters contain higher Pu than subsurface particulates. 241 Am was found to exhibit much stronger particle association in accord with its known greater particle reactivity. In the high Pu deep water layer, particle associated Pu dropped to close to 1% of total Pu concentration. Together with a correlated increase in the proportion of oxidized Pu in this layer close to the sediment-water interface, this is clear evidence of remobilization of Pu from particles at, or near to, the interface. 55 Fe distributions on filtered particulates indicate a much deeper depth distribution relative to the transuranics. This may reflect both a higher particle association reactivity in respect to scavenging and a longer exposure history to scavenging. (author)

  20. Depth distribution analysis of martensitic transformations in Xe implanted austenitic stainless steel

    International Nuclear Information System (INIS)

    Johnson, E.; Johansen, A.; Sarholt-Kristensen, L.; Chechenin, N.G.; Grabaek, L.; Bohr, J.

    1988-01-01

    In this work we present results from a depth distribution analysis of the martensitic phase change occurring in Xe implanted single crystals of austenitic stainless steel. Analysis was done by 'in situ' RBS/channeling analysis, X-ray diffraction and cross-section transmission electron microscopy (XTEM) of the implanted surface. It is found that the martensitic transformation of the surface layer occurs for fluences above 1x10 20 m -2 . The thickness of the transformed layer increases with fluence to ≅ 150 nm at 1x10 21 m -2 , which far exceeds the range plus straggling of the implanted Xe as calculated by the TRIM computer simulation code. Simulations using the MARLOWE code indicate that the thickness of the transformed layer coincides with the range of the small fraction of ions channeled under random implantation conditions. Using cross sectional TEM on the Xe implanted crystals, the depth distribution of gas inclusions and defects can be directly observed. Using X-ray diffraction on implanted single crystals, the solid epitaxial nature of the Xe inclusions, induced prior to the martensitic transformation, was established. The lattice constant obtained from the broad diffraction peak indicates that the pressure in the inclusions is ≅ 5 GPa. (orig./BHO)

  1. Calculated depth-dose distributions for H+ and He+ beams in liquid water

    International Nuclear Information System (INIS)

    Garcia-Molina, Rafael; Abril, Isabel; Denton, Cristian D.; Heredia-Avalos, Santiago; Kyriakou, Ioanna; Emfietzoglou, Dimitris

    2009-01-01

    We have calculated the dose distribution delivered by proton and helium beams in liquid water as a function of the target-depth, for incident energies in the range 0.5-10 MeV/u. The motion of the projectiles through the stopping medium is simulated by a code that combines Monte Carlo and a finite differences algorithm to consider the electronic stopping power, evaluated in the dielectric framework, and the multiple nuclear scattering with the target nuclei. Changes in projectile charge-state are taken into account dynamically as it moves through the target. We use the MELF-GOS model to describe the energy loss function of liquid water, obtaining a value of 79.4 eV for its mean excitation energy. Our calculated stopping powers and depth-dose distributions are compared with those obtained using other methods to describe the energy loss function of liquid water, such as the extended Drude and the Penn models, as well as with the prediction of the SRIM code and the tables of ICRU.

  2. Reconstruction of original indium distribution in InGaAs quantum wells from experimental SIMS depth profiles

    Energy Technology Data Exchange (ETDEWEB)

    Kudriavtsev, Yu., E-mail: yuriyk@cinvestav.mx [Departamento Ingeniería Eléctrica – SEES, CINVESTAV-IPN, Av. IPN #2508, D.F., México (Mexico); Asomoza, R. [Departamento Ingeniería Eléctrica – SEES, CINVESTAV-IPN, Av. IPN #2508, D.F., México (Mexico); Gallardo-Hernandez, S.; Ramirez-Lopez, M.; Lopez-Lopez, M. [Departamento de Física, CINVESTAV-IPN, México (Mexico); Nevedomsky, V.; Moiseev, K. [Ioffe Physical Technical Institute, S-Petersburg (Russian Federation)

    2014-11-15

    Depth profiling analysis of InGaAs/GaAs hetero-structures grown by MBE on GaAs (0 0 1) substrates is reported. A novel two-step procedure for de-convolving experimental SIMS depth distribution is employed and the original In distribution in InGaAs quantum wells (QW) is estimated. The QW thickness calculated from the de-convolved profiles is shown to be in good agreement with the cross-sectional TEM images. The experimental In depth profile is shifted from the original In distribution due to the ion mixing process during depth profiling analysis. It is shown that the de-convolution procedure is suitable for reconstruction of the original QW width and depth by SIMS even for relatively high primary ion energies.

  3. Topographic, meteorologic, and canopy controls on the scaling characteristics of the spatial distribution of snow depth fields

    Science.gov (United States)

    Ernesto Trujillo; Jorge A. Ramirez; Kelly J. Elder

    2007-01-01

    In this study, LIDAR snow depths, bare ground elevations (topography), and elevations filtered to the top of vegetation (topography + vegetation) in five 1-km2 areas are used to determine whether the spatial distribution of snow depth exhibits scale invariance, and the control that vegetation, topography, and winds exert on such behavior. The one-dimensional and mean...

  4. Microbiome variation in corals with distinct depth distribution ranges across a shallow-mesophotic gradient (15-85 m)

    Science.gov (United States)

    Glasl, Bettina; Bongaerts, Pim; Elisabeth, Nathalie H.; Hoegh-Guldberg, Ove; Herndl, Gerhard J.; Frade, Pedro R.

    2017-06-01

    Mesophotic coral ecosystems (MCEs) are generally poorly studied, and our knowledge of lower MCEs (below 60 m depth) is largely limited to visual surveys. Here, we provide a first detailed assessment of the prokaryotic community associated with scleractinian corals over a depth gradient to the lower mesophotic realm (15-85 m). Specimens of three Caribbean coral species exhibiting differences in their depth distribution ranges ( Agaricia grahamae, Madracis pharensis and Stephanocoenia intersepta) were collected with a manned submersible on the island of Curaçao, and their prokaryotic communities assessed using 16S rRNA gene sequencing analysis. Corals with narrower depth distribution ranges (depth-specialists) were associated with a stable prokaryotic community, whereas corals with a broader niche range (depth-generalists) revealed a higher variability in their prokaryotic community. The observed depth effects match previously described patterns in Symbiodinium depth zonation. This highlights the contribution of structured microbial communities over depth to the coral's ability to colonize a broader depth range.

  5. AFSC/RACE/FBEP/Ryer: Polychaete worm tubes modify juvenile northern rock sole Lepidopsetta polyxystra depth distribution in Kodiak nurseries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study that evaluates whether inter-annual variability in the depth distribution of juvenile northern rock sole on their nursery grounds around...

  6. Abundance, diversity and depth distribution of Planctomycetes in northern Sphagnum-dominated wetlands

    Directory of Open Access Journals (Sweden)

    Svetlana N. Dedysh

    2012-01-01

    Full Text Available Members of the bacterial phylum Planctomycetes inhabit various aquatic and terrestrial environments. In this study, fluorescence in situ hybridization (FISH was applied to assess the abundance and depth distribution of these bacteria in nine different Sphagnum-dominated wetlands of Northern Russia. Planctomycetes were most abundant in the oxic part of peat bog profiles. The respective cell numbers were in the range 1.1-6.7×107 cells per gram of wet peat, comprising 2 to 14% of total bacterial cells and displaying linear correlation to the peat water pH. Most peatland sites showed a sharp decline of planctomycete abundance with depth, while in two particular sites this decline was followed by a second population maximum in an anoxic part of the bog profile. Oxic peat layers were dominated by representatives of the Isosphaera-Singulisphaera group, while anoxic part of the bog profile was inhabited mostly by Zavarzinella- and Pirellula-like planctomycetes. Phylogenetically related bacteria of the candidate division OP3 were detected in both oxic and anoxic peat with cell densities of 0.6-4.6×106 cells per gram of wet peat.

  7. Depth distribution analysis of Martensitic transformations in Xe implanted austenitic stainless steel

    DEFF Research Database (Denmark)

    Johnson, E.; Gerritsen, E.; Chechenin, N.G.

    1989-01-01

    In recent years the implantation of noble gases in metals has been found to induce some exciting phenomena such as formation of inclusions containing solid gas at extremely high pressures. In stainless steels these inclusions are the origin of a stress-induced martensitic fcc → bcc phase...... transformation in the implanted layer. In this work we present results from a depth distribution analysis of the martensitic phase change occurring in Xe implanted single crystals of austenitic stainless steel. Analysis was done by in situ RBS/channeling analysis, X-ray diffraction and cross-section transmission...... electron microscopy (XTEM) of the implanted surface. It is found that the martensitic transformation of the surface layer occurs for fluences above 1 × 1020 m−2. The thickness of the transformed layer increases with fluence to ≈ 150 nm at 1 × 10 21 m−2, which far exceeds the range plus straggling...

  8. The 2005 Tarapaca, Chile, Intermediate-depth Earthquake: Evidence of Heterogeneous Fluid Distribution Across the Plate?

    Science.gov (United States)

    Kuge, K.; Kase, Y.; Urata, Y.; Campos, J.; Perez, A.

    2008-12-01

    The physical mechanism of intermediate-depth earthquakes remains unsolved, and dehydration embrittlement in subducting plates is a candidate. An earthquake of Mw7.8 occurred at a depth of 115 km beneath Tarapaca, Chile. In this study, we suggest that the earthquake rupture can be attributed to heterogeneous fluid distribution across the subducting plate. The distribution of aftershocks suggests that the earthquake occurred on the subhorizontal fault plane. By modeling regional waveforms, we determined the spatiotemporal distribution of moment release on the fault plane, testing a different suite of velocity models and hypocenters. Two patches of high slip were robustly obtained, although their geometry tends to vary. We tested the results separately by computing the synthetic teleseismic P and pP waveforms. Observed P waveforms are generally modeled, whereas two pulses of observed pP require that the two patches are in the WNW-ESE direction. From the selected moment-release evolution, the dynamic rupture model was constructed by means of Mikumo et al. (1998). The model shows two patches of high dynamic stress drop. Notable is a region of negative stress drop between the two patches. This was required so that the region could lack wave radiation but propagate rupture from the first to the second patches. We found from teleseismic P that the radiation efficiency of the earthquake is relatively small, which can support the existence of negative stress drop during the rupture. The heterogeneous distribution of stress drop that we found can be caused by fluid. The T-P condition of dehydration explains the locations of double seismic zones (e.g. Hacker et al., 2003). The distance between the two patches of high stress drop agrees with the distance between the upper and lower layers of the double seismic zone observed in the south (Rietbrock and Waldhauser, 2004). The two patches can be parts of the double seismic zone, indicating the existence of fluid from dehydration

  9. In-Space Distributed Fiber Optic Hydrogen Leak Sensor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband Photonics Inc. proposes development of a patent-pending distributed fiber optic sensor for in-space hydrogen leak detection. Reliable and fast detection of...

  10. The determination of gold depth distribution in semiconductor silicon-potential interferences inherent in NAA by radiation damages

    International Nuclear Information System (INIS)

    Rudolph, P.; Lange, A.; Flachowsky, J.

    1986-01-01

    Gold is used quite extensively to control the charge storage time of high speed diodes and transistors. Therefore, the diffusion of gold into silicon wafers of finite thickness is important in the design and fabrication of these devices. Therefore it is necessary to estimate exactly concentration and depth distribution of gold formed by gold doping. Usually, gold content and depth distribution has been estimate by neutron activation analysis with step by step etching techniques. But during the irradiation in a nuclear fuel reactor the silicon wafers undergo minute or pronounced radiation damages which may affect the depth profiles of gold concentration. (author)

  11. Hydrogen and steam distribution following a small-break LOCA in large dry containment

    Institute of Scientific and Technical Information of China (English)

    DENG Jian; CAO Xuewu

    2007-01-01

    The hydrogen deflagration is one of the major risk contributors to threaten the integrity of the containment in a nuclear power plant, and hydrogen control in the case of severe accidents is required by nuclear regulations.Based on the large dry containment model developed with the integral severe-accident analysis tool, a small-break loss-of-coolant-accident (LOCA) without HPI, LPI, AFW and containment sprays, leading to the core degradation and large hydrogen generation, is calculated. Hydrogen and steam distribution in containment compartments is investigated. The analysis results show that significant hydrogen deflagration risk exits in the reactor coolant pump (RCP)compartment and the cavity during the early period, if no actions are taken to mitigate the effects of hydrogen accumulation.

  12. Thermal energy distribution analysis for hydrogen production in RGTT200K conceptual design

    International Nuclear Information System (INIS)

    Tumpal Pandiangan; Ign Djoko Irianto

    2011-01-01

    RGTT200K is a high temperature gas-cooled reactor (HTGR) which conceptually designed for power generation, hydrogen production and desalination. Hydrogen production process in this design uses thermochemical method of Iodine-Sulphur. To increase the thermal conversion efficiency in hydrogen production installations, it needs to design a thermal energy distribution and temperature associated with the process of thermo-chemical processes in the method of Iodine-Sulphur. In this method there are 7 kinds of processes: (i) H 2 SO4 decomposition reaction (ii) treatment of vaporization (iii) treatment of pre vaporizer (iv) treatment of flash 4 (v) treatment of decomposition of HI (vi) treatment of the flash 1-3 and (vii) Bunsen reaction. To regulate the distribution of energy and temperature appropriate to the needs of each process used 3 pieces of heat exchanger (HE). Calculation of energy distribution through the distribution of helium gas flow has been done with Scilab application programs, so that can know the distribution of thermal energy for production of 1 mole of hydrogen. From this model, it can calculate the thermal energy requirement for production of hydrogen at the desired capacity. In the conceptual design of RGTT200K, helium discharge has been designed by 20 kg/s, so that an efficient hydrogen production capacity needed to produce 15347.8 for 21.74 mole of H 2 . (author)

  13. Energy distribution and transfer in flowing hydrogen microwave plasmas

    International Nuclear Information System (INIS)

    Chapman, R.A.

    1987-01-01

    This thesis is an experimental investigation of the physical and chemical properties of a hydrogen discharge in a flowing microwave plasma system. The plasma system is the mechanisms utilized in an electrothermal propulsion concept to convert electromagnetic energy into the kinetic energy of flowing hydrogen gas. The plasmas are generated inside a 20-cm ID resonant cavity at a driving frequency of 2.45 GHz. The flowing gas is contained in a coaxially positioned 22-mm ID quartz discharge tube. The physical and chemical properties are examined for absorbed powers of 20-100 W, pressures of 0.5-10 torr, and flow rates of 0-10,000 μ-moles/sec. A calorimetry system enclosing the plasma system to accurately measure the energy inputs and outputs has been developed. The rate of energy that is transferred to the hydrogen gas as it flows through the plasma system is determined as a function of absorbed power, pressure, and flow rate to +/-1.8 W from an energy balance around the system. The percentage of power that is transferred to the gas is found to increase with increasing flow rate, decrease with increasing pressure, and to be independent of absorbed power

  14. Stress distributions due to hydrogen concentrations in electrochemically charged and aged austenitic stainless steel

    International Nuclear Information System (INIS)

    Rozenak, P.; Loew, A.

    2008-01-01

    As a result of hydrogen concentration gradients in type austenitic stainless steels, formed during electrochemical charging and followed by hydrogen loss during aging, at room temperature, surface stresses were developed. These stresses were measured by X-ray technique and the crack formation thus induced could be studied using equilibrium stress equations. After various electrochemical charging and aging times, X-ray diffraction patterns obtained from samples indicated that the reflected and broadened diffraction peaks are the result of the formation of a non-uniform but continuous solid solution in the austenitic matrix. Since both hydrogen penetrations during charging and hydrogen release during aging are diffusion controlled processes and huge hydrogen concentration gradients in the thin surface layer, at depths comparable with the depth of X-ray penetration, are observed. The non-uniform hydrogen concentration in the austenitic matrix, results to the non-uniform expansion of the atomic microstructure and latter inevitably leads to the development of internal stresses. The internal stresses development formulae's are very similar to those relating to non-uniform heating of the materials, where thermal stresses appear due to non-uniform expansion or contraction. The relevant well developed theory is applicable in our case of non-uniform hydrogen concentrations in a solid solution of electrochemically charged and aged austenitic matrix. A few cracks were present on the surface after some minutes of electrochemical charging and the severity of cracking increased as hydrogen was lost during subsequent aging. This is consistent with the expectation of high compressive stresses in the bulk of the specimen during charging and high tensile surface stresses (at the level of 1 x 10 11 Pa) during the aging process. These stresses can induce the formation of surface cracks during the aging process after electrochemical charging in the AISI 316 stainless steel

  15. Some practical aspects of depth profiling gases in metals by proton backscattering: application to helium and hydrogen isotopes

    International Nuclear Information System (INIS)

    Blewer, R.S.

    1975-01-01

    Maximum detection sensitivity for hydrogen isotopes and helium is achieved by employing thin foil samples backed by a ''beam trap'' to prevent any portion of the incident beam which is not backscattered in the foil sample from reaching the detector. Measurements have been made to determine the magnitude and origin of ''tail'' or''background'' counts which appear in parts of the spectra which ideally should contain no counts and which, by their presence, reduce the detection sensitivity that should theoretically be achievable for light elements. For copper foil targets, the ratio of the counts per channel of the Cu peak to the counts per channel for the background is approximately 5 x 10 3 . The energy distribution of the background has been measured and leads one to the conclusion that for the apparatus used, these counts arise principally from decollimated incident beam protons which strike the sample holder instead of the foil sample. The enhancement in elastic scattering cross section for protons incident on 4 He is discussed and the enhancement factor for a number of other low Z elements is tabulated both for E 0 = 2.5 MeV and for energies at which sharp resonances exist. Example spectra will be drawn from fusion reactor first wall studies presently being conducted which illustrate the effect of applying the principles discussed

  16. DNA analysis of soil extracts can be used to investigate fine root depth distribution of trees

    Science.gov (United States)

    Bithell, Sean L.; Tran-Nguyen, Lucy T. T.; Hearnden, Mark N.; Hartley, Diana M.

    2015-01-01

    Understanding the root distribution of trees by soil coring is time-consuming as it requires the separation of roots from soil and classification of roots into particular size classes. This labour-intensive process can limit sample throughput and therefore sampling intensity. We investigated the use of quantitative polymerase chain reaction (qPCR) on soil DNA extractions to determine live fine root DNA density (RDD, mg DNA m−2) for mango (Mangifera indica) trees. The specificity of the qPCR was tested against DNA extracted from 10 mango cultivars and 14 weed species. All mango cultivars and no weeds were detected. Mango DNA was successfully quantified from control soil spiked with mango roots and weed species. The DNA yield of mango root sections stored in moist soil at 23–28 °C declined after 15 days to low concentrations as roots decayed, indicating that dead root materials in moist soil would not cause false-positive results. To separate large roots from samples, a root separation method for field samples was used to target the root fragments remaining in sieved (minimum 2 mm aperture) soil for RDD comparisons. Using this method we compared the seasonal RDD values of fine roots for five mango rootstock cultivars in a field trial. The mean cultivar DNA yields by depth from root fragments in the sieved soil samples had the strongest relationship (adjusted multiple R2 = 0.9307, P < 0.001) with the dry matter (g m−2) of fine (diameter <0.64 mm) roots removed from the soil by sieving. This method provides a species-specific and rapid means of comparing the distribution and concentration of live fine roots of trees in orchards using soil samples up to 500 g. PMID:25552675

  17. Analyses of hydrogen in quartz and in sapphire using depth profiling by ERDA at atmospheric pressure: Comparison with resonant NRA and SIMS

    International Nuclear Information System (INIS)

    Reiche, Ina; Castaing, Jacques; Calligaro, Thomas; Salomon, Joseph; Aucouturier, Marc; Reinholz, Uwe; Weise, Hans-Peter

    2006-01-01

    Hydrogen is present in anhydrous materials as a result of their synthesis and of their environment during conservation. IBA provides techniques to measure H concentration depth profiles allowing to identify various aspects of the materials including the history of objects such as gemstones used in cultural heritage. A newly established ERDA set-up, using an external microbeam of alpha particles, has been developed to study hydrated near-surface layers in quartz and sapphire by non-destructive H depth profiling in different atmospheres. The samples were also analysed using resonant NRA and SIMS

  18. Analyses of hydrogen in quartz and in sapphire using depth profiling by ERDA at atmospheric pressure: Comparison with resonant NRA and SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Reiche, Ina [Laboratoire du Centre de recherche et de restauration des musees de France (C2RMF), UMR 171 CNRS, 14 quai Francois Mitterrand, 75001 Paris (France); Castaing, Jacques [Laboratoire du Centre de recherche et de restauration des musees de France (C2RMF), UMR 171 CNRS, 14 quai Francois Mitterrand, 75001 Paris (France)]. E-mail: jacques.castaing@culture.fr; Calligaro, Thomas [Laboratoire du Centre de recherche et de restauration des musees de France (C2RMF), UMR 171 CNRS, 14 quai Francois Mitterrand, 75001 Paris (France); Salomon, Joseph [Laboratoire du Centre de recherche et de restauration des musees de France (C2RMF), UMR 171 CNRS, 14 quai Francois Mitterrand, 75001 Paris (France); Aucouturier, Marc [Laboratoire du Centre de recherche et de restauration des musees de France (C2RMF), UMR 171 CNRS, 14 quai Francois Mitterrand, 75001 Paris (France); Reinholz, Uwe [Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Weise, Hans-Peter [Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin (Germany)

    2006-08-15

    Hydrogen is present in anhydrous materials as a result of their synthesis and of their environment during conservation. IBA provides techniques to measure H concentration depth profiles allowing to identify various aspects of the materials including the history of objects such as gemstones used in cultural heritage. A newly established ERDA set-up, using an external microbeam of alpha particles, has been developed to study hydrated near-surface layers in quartz and sapphire by non-destructive H depth profiling in different atmospheres. The samples were also analysed using resonant NRA and SIMS.

  19. Depth distribution of 137Cs adsorption property of clay minerals influenced by mineral weathering

    International Nuclear Information System (INIS)

    Nakao, Atsushi; Funakawa, Shinya; Kosaki, Takashi

    2007-01-01

    Radiocesium adsorption potential of mica clay mineral can increase as it is weathered, because K depletion in mica interlayer sites generates new Cs selective sites. However, in soils weathered under field conditions, the increase in 137 Cs adsorption potential associated with mineral weathering has not been observed extensively. We investigated four soil profiles from Japan and Thailand with different soil pH ranges (3.3-4.0, 4.2-4.3, 5.0-5.7, and 5.5-7.3). The solid/liquid distribution coefficients of Cs ( Cs Kd) in clay ( 137 Cs adsorption potential of mica clay minerals. In three soil profiles, Cs Kd value in clay was the largest at a surface horizon and was decreased with depth, whereas in the most acidic of Podzolic soil profile, it was the largest at B horizon. The large Cs Kd value in surface clays relative to deeper horizons were well associated with that of 2.0-1.0 μm clay fraction. We assumed that the 137 Cs adsorption potential increased at surface horizons mainly because coarser clay micas were weathered and generated Cs selective sites. The exceptional result obtained in Podzolic soil profile suggests that too intensive weathering destruct mica structure and may decrease in Cs adsorption potential of mica clay minerals. (author)

  20. Hydrogen, a bridge between mobility and distributed generation. Some consideration towards the hydrogen economy

    International Nuclear Information System (INIS)

    Valentino Romeri

    2006-01-01

    In this paper were analysed the most recent energy initiatives started by some national and international institution, with particular focus on hydrogen and fuel cell. It were also overviewed the national road-maps towards the hydrogen economy. In 2004, based on the most authoritative available data regarding future FCVs penetration it was observed that, if vehicle power-generation system fuel cell based becomes more sophisticated, the role of the vehicles within the power grid might change. Fuel Cell Vehicle (FVC) could become a new power-generation source, supplying electricity to home and to the grid. Also, it was defined the dimension of this new kind of power generation source in different areas and it was compared with the related power grid installed generation capacity and it was found that this new source could be a multiple of the foreseeable installed capacity in year 2030. In the present work it was revised the analysis with the most recent scenarios and it was found that the results do not change significantly. Unfortunately this kind of analysis is still not considered in the energy debate or in the road-maps towards the hydrogen economy. (author)

  1. Prediction of hydrogen distribution in the reactor building in CANDU6 plant

    International Nuclear Information System (INIS)

    Jin, Y.; Song, Y.

    2008-01-01

    The CANDU plants have a lot of zircaloy. The fuel cladding, calandria tubes and pressure tubes are made of zircaloy. The zircaloy can be oxidized and hydrogen is generated during severe accident progression. The detonation or deflagration to detonation transition (DDT) due to hydrogen combustion may occur if the local hydrogen concentration or global hydrogen concentration exceeds certain value. The detonation may result in the rupture of the reactor building. The inside of the reactor building of CANDU plants is complex. So prediction of hydrogen distribution in the reactor building is important. This prediction is made using ISAAC code and GOTHIC code. ISAAC code partitioned the reactor building in to 7 compartments. GOTHIC code modeled the CANDU6 reactor building using 12 nodes. The hydrogen concentrations in the various compartments in the reactor building are compared. GOTHIC code slightly underpredicts hydrogen concentration in the F/M rooms than ISAAC code, but trend is same. The hydrogen concentration in the boiler room and the moderator room shows almost same as for both codes. (author)

  2. The Need to introduce CFD Methodology in Analyze Hydrogen Distribution for Postulated Severe Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Na, Hanbee; Park, Sukyung; Kim, Kyuntae [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Lee, Jongkwang [Hanbat National University, Daejeon (Korea, Republic of); Kwon, Sejin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-10-15

    The regulatory requirements for combustible gas control systems in Korea is that mean hydrogen mole fraction shall be lower than 10 %, containment integrity shall be kept from combustion of hydrogen, and detonation and global fast turbulent combustion shall be avoided. KHNP provided some analysis which show hydrogen mole fraction is less than 10 % and detonation and global fast turbulence combustion are avoided for postulated severe accident events which covered over 90 % of CDF (core damage frequency) for each NPP. The results were from MAAP code that can simulate from the initiation of the accidents to hydrogen distribution inside containments. It is a Lumped-Parameter codes in which the transport of energy and mass is possible in only predetermined one direction. Therefore, there has been a long-history dispute whether one-dimensional LP codes could simulate the transportation of hydrogen accurately. For example, KHNP made a MAAP model to simulate hydrogen distribution in KSNP (Korean Standard Nuclear Plants), and the containment free volume is divided into 27 nodes in which it is assumed all the properties like each molecule mole fraction and temperate are uniform in each node. In addition, the maximum volume size of them is over 22,000 m{sup 3}, and it is not quite confident that the mole fraction of each molecules and temperature are uniform in the big size space. As for the stress test results of the Wolsong 1, civil experts asked KHNP to conduct hydrogen distribution analysis using Computational Fluid Dynamics (CFD) methodology, and if needed to install hydrogen ignitors in Wolsong 1 NPP. As a reviewer for KHNP's post actions to the Stress Test, the author also asked KHNP to do CFD analysis of hydrogen distribution, and KHNP finally agreed to analyze it using CFD by 2017. KHNP submitted a Shin-hanul 1 and 2 Operation License application in 2015, and the author also asked it to do CFD analysis to simulate hydrogen distribution for Shin-hanul 1 and 2

  3. Depth distribution of preferential flow patterns in a sandy loam soil as affected by tillage

    Directory of Open Access Journals (Sweden)

    C. T. Petersen

    1997-01-01

    Full Text Available Dye-tracer studies using the anionic dye Brilliant Blue FCF were conducted on a structured sandy loam soil (Typic Agrudalf. 25 mm of dye solution was applied to the surface of 11 1.6 x 1.6 m field plots, some of which had been subjected to conventional seed bed preparation (harrowing while others had been rotovated to either 5 or 15 cm depth before sowing. The soil was excavated to about 160 cm depth one or two days after dye application. Flow patterns and structural features appearing on vertical or horizontal cross sections were examined and photographed. The flow patterns were digitized, and depth functions for the number of activated flow pathways and the degree of dye coverage were calculated. Dye was found below 100 cm depth on 26 out of 33 vertical cross sections made in conventionally tilled plots showing that preferential flow was a prevailing phenomenon. The depth-averaged number of stained flow pathways in the 25-100 cm layer was significantly smaller in a plot rotovated to 5 cm depth than in a conventionally tilled plot, both under relatively dry initial soil conditions and when the entire soil profiles were initially at field capacity. There were no examples of dye penetration below 25 cm depth one month after deep rotovation. Distinct horizontal structures in flow patterns appearing at 20-40 cm depth coupled with changes in flow domains indicated soil layering with abrupt changes in soil structure and hydraulic properties.

  4. Transient dynamic finite element analysis of hydrogen distribution test chamber structure for hydrogen combustion loads

    International Nuclear Information System (INIS)

    Singh, R.K.; Redlinger, R.; Breitung, W.

    2005-09-01

    Design and analysis of blast resistant structures is an important area of safety research in nuclear, aerospace, chemical process and vehicle industries. Institute for Nuclear and Energy Technologies (IKET) of Research Centre- Karlsruhe (Forschungszentrum Karlsruhe or FZK) in Germany is pursuing active research on the entire spectrum of safety evaluation for efficient hydrogen management in case of the postulated design basis and beyond the design basis severe accidents for nuclear and non-nuclear applications. This report concentrates on the consequence analysis of hydrogen combustion accidents with emphasis on the structural safety assessment. The transient finite element simulation results obtained for 2gm, 4gm, 8gm and 16gm hydrogen combustion experiments concluded recently on the test-cell structure are described. The frequencies and damping of the test-cell observed during the hammer tests and the combustion experiments are used for the present three dimensional finite element model qualification. For the numerical transient dynamic evaluation of the test-cell structure, the pressure time history data computed with CFD code COM-3D is used for the four combustion experiments. Detail comparisons of the present numerical results for the four combustion experiments with the observed time signals are carried out to evaluate the structural connection behavior. For all the combustion experiments excellent agreement is noted for the computed accelerations and displacements at the standard transducer locations, where the measurements were made during the different combustion tests. In addition inelastic analysis is also presented for the test-cell structure to evaluate the limiting impulsive and quasi-static pressure loads. These results are used to evaluate the response of the test cell structure for the postulated over pressurization of the test-cell due to the blast load generated in case of 64 gm hydrogen ignition for which additional sets of computations were

  5. Direct depth distribution measurement of deuterium in bulk tungsten exposed to high-flux plasma

    Directory of Open Access Journals (Sweden)

    C. N. Taylor

    2017-05-01

    Full Text Available Understanding tritium retention and permeation in plasma-facing components is critical for fusion safety and fuel cycle control. Glow discharge optical emission spectroscopy (GD-OES is shown to be an effective tool to reveal the depth profile of deuterium in tungsten. Results confirm the detection of deuterium. A ∼46 μm depth profile revealed that the deuterium content decreased precipitously in the first 7 μm, and detectable amounts were observed to depths in excess of 20 μm. The large probing depth of GD-OES (up to 100s of μm enables studies not previously accessible to the more conventional techniques for investigating deuterium retention. Of particular applicability is the use of GD-OES to measure the depth profile for experiments where high deuterium concentration in the bulk material is expected: deuterium retention in neutron irradiated materials, and ultra-high deuterium fluences in burning plasma environment.

  6. [Effects of submarine topography and water depth on distribution of pelagic fish community in minnan-taiwan bank fishing ground].

    Science.gov (United States)

    Fang, Shuimei; Yang, Shengyun; Zhang, Chengmao; Zhu, Jinfu

    2002-11-01

    According to the fishing record of the light-seine information vessel in Minnan-Taiwan bank ground during 1989 to 1999, the effects of submarine topography and water depth on distribution of pelagic fish community in Minnan-Taiwan bank fishing ground was studied. The results showed that the pelagic fish distributed concentratively, while the submarine topography and water depth varied widely, but in different fishing regions, the distribution of pelagic fishes was uneven. The distribution of fishing yield increased from north to south, and closed up from sides of the bank to south or north in the regions. Pelagic fish distributed mainly in mixed water in the southern Taiwan Strait, and in warm water in the Taiwan Strait. The central fishing grounds were at high salt regions. Close gathering regions of pelagic fish or central fishing ground would be varied with the seasonal variation of mixed water in the southern Taiwan Strait and warm water in the Taiwan Strait. Central fishing ground was not only related to submarine topography and water depth, but also related to wind direction, wind-power and various water systems. In the fishing ground, the gathering depth of pelagic fish was 30-60 m in spring and summer, and 40-80 m in autumn and winter.

  7. Microanalysis of Fluorine Contamination and its Depth Distribution in Zircaloy by the Use of a Charged Particle Nuclear Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, E; Starfelt, N

    1966-07-15

    Fluorine contamination on and below the surface of zircaloy has been studied by means of proton irradiation using a Van de Graaff accelerator and the detection of prompt gamma radiation from the {sup 19}F (p, {alpha}{gamma}) {sup 16}O reaction. Formulae for deriving depth distributions of impurities from the measured counting rates have been derived. The influence of energy straggling on the depth resolution has been studied. Both the total amount and the depth distribution have been measured in samples, which have undergone different treatments. Because of the high yield from the reaction used, a quantity of fluorine less than 0. 01 {mu}g/cm{sup 2} can be detected by this method.

  8. Depth-related distribution of a key gene of the tetraether lipid biosynthetic pathway in marine Thaumarchaeota

    NARCIS (Netherlands)

    Villanueva, Laura; Schouten, Stefan; Sinninghe Damsté, Jaap S.

    2015-01-01

    The distribution of isoprenoid glycerol dialkyl glycerol tetraethers (GDGT) lipids synthesized by Thaumarchaeota has been shown to be temperature-dependent in world oceans. Depth-related differences in the ammonia monooxygenase (amoA) of Thaumarchaeota have led to the classification of 'shallow' and

  9. Electron momentum distributions and binding energies for the valence orbitals of hydrogen bromide and hydrogen iodide

    International Nuclear Information System (INIS)

    Brion, C.E.; McCarthy, I.E.; Suzuki, I.H.; Weigold, E.; Williams, G.R.J.; Bedford, K.L.; Kunz, A.B.; Weidman, R.

    1981-12-01

    The electron binding energy spectra and momentum distributions have been obtained for the valence orbitals of HBr and HI using noncoplanar symmetric electron coincidence spectroscopy at 1200eV. The weakly bonding inner valence ns orbitals, which have not been previously observed, have their spectroscopic (pole) strength severely split among a number of ion states. For HBr the strength of the main inner valence (ns) transition is 0.42 0.03 whereas for HI it is 0.37 0.04, in close agreement with that observed for the valence s orbitals of the corresponding isoelectronic inert gas atoms. The spectroscopic strength for the two outermost orbitals is found to be close to unity, in agreement with many body Green's function calculations. The measured momentum distributions are compared with several spherically averaged MO momentum distributions, as well as (for HBr) with a Green's function calculation of the generalized overlap amplitude (GOA). The GOA momentum distributions are in excellent agreement with the HBr data, both in shape and relative magnitude. Not all of the MO momentum distributions are in reasonable agreement with the data. Comparison is also made with the calculated momentum distributions for Kr, Br, Xe and I

  10. Angular distribution of protons emitted from the hydrogen plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Antanasijevic, R.; Maric, Z.; Vukovic, J.; Grabez, B. E-mail: grabez@phy.bg.ac.yu; Djordjevic, D.; Joksimovic, D.; Udovicic, V.; Dragic, A.; Stanojevic, J.; Banjanac, R.; Jokovic, D

    2003-06-01

    Angular distribution of emitted protons was measured. The protons were detected with NTD LR-115 placed at the specially constructed semi-spherical holder, which contains 17 different pinhole cameras. The mechanism of proton acceleration and emission are studied theoretically and experimental results are compared with theoretical predictions.

  11. Angular distribution of protons emitted from the hydrogen plasma focus

    International Nuclear Information System (INIS)

    Antanasijevic, R.; Maric, Z.; Vukovic, J.; Grabez, B.; Djordjevic, D.; Joksimovic, D.; Udovicic, V.; Dragic, A.; Stanojevic, J.; Banjanac, R.; Jokovic, D.

    2003-01-01

    Angular distribution of emitted protons was measured. The protons were detected with NTD LR-115 placed at the specially constructed semi-spherical holder, which contains 17 different pinhole cameras. The mechanism of proton acceleration and emission are studied theoretically and experimental results are compared with theoretical predictions

  12. Hydrogen transport in solids with traps in the case of continuum distribution of detrapping energies

    International Nuclear Information System (INIS)

    Krasheninnikov, S I; Smirnov, R D; Marenkov, E D; Pisarev, A A

    2014-01-01

    Tritium retention in the first wall material is one of the key issues in the performance of future fusion reactors. Transport of hydrogenic species in these materials is most commonly treated as diffusion affected by trapping/detrapping processes. Usually only several trap types differing in their activation energies of hydrogen release are considered (up to three types in the TMAP7 code). We suggest that in some cases (e.g. highly damaged or disordered media) the hydrogen trapping/detrapping process is better characterized by a continuum distribution of traps over their detrapping energies. Within a random walk model we show that this assumption leads to qualitative changes in hydrogen transport in solids. Using this model we explain experimental findings on temporal dependence of deuterium outgassing from tokamaks, first wall. (paper)

  13. Momentum distributions and ionization potentials for the valence orbitals of hydrogen fluoride and hydrogen chloride

    International Nuclear Information System (INIS)

    Brion, C.E.; Hood, S.T.; Suzuki, I.H.; Weigold, E.

    1980-02-01

    The binding energy spectra and momentum distributions for the valence orbitals of HF and HCl have been obtained using (e,2e) spectroscopy with symmetric kinematics at 1200eV and 400eV. For HCl the strength of the innermost valence orbital (4sigma) is found to be significantly split among several ion states in the range 25eV to 41eV. The corresponding orbital in HF (2sigma) is however not significantly split among ion states. The measured momentum distributions are compared with the results of several calculatons of at least double zeta quality as well as with a one particle Green's function calculation of the generalized overlap amplitude. Agreement in shape is quite good for the innermost orbitals, but for the π and outer sigma orbitals of HF the momentum distributions calculated directly from the molecular orbitals are significantly more extended in momentum space than the measured distributions. The Green's function calculations give momentum distributions in good agreement with the data and pole strengths for transitions in qualitative agreement with the observed cross sections

  14. Angular distribution in proton-hydrogen charge-transfer collisions

    International Nuclear Information System (INIS)

    Glembocki, O.; Halpern, A.M.

    1977-01-01

    Theoretical angular distributions for p-H charge transfer to the 1s state for energies of 1 keV and above have been examined and compared for three approximation schemes: the plane-wave Born approximation of Jackson and Schiff (JS), the Coulomb projected Born approximation of Geltman (G), and the distorted-wave eikonal approximation of one of the authors (D). The sharp dip in the forward distribution characteristic of JS is found to exist in G and D as well. As expected, G and D give identical results for all but the lowest energies. In the cases of G and D the dip, which is located close to that of JS, disappears and then reappears as the energy rises. Analytic high-energy limits for the angular dependence in both the JS and G cases have been found and are discussed

  15. IMPROVING INTERFEROMETRIC NULL DEPTH MEASUREMENTS USING STATISTICAL DISTRIBUTIONS: THEORY AND FIRST RESULTS WITH THE PALOMAR FIBER NULLER

    International Nuclear Information System (INIS)

    Hanot, C.; Riaud, P.; Absil, O.; Mennesson, B.; Martin, S.; Liewer, K.; Loya, F.; Mawet, D.; Serabyn, E.

    2011-01-01

    A new 'self-calibrated' statistical analysis method has been developed for the reduction of nulling interferometry data. The idea is to use the statistical distributions of the fluctuating null depth and beam intensities to retrieve the astrophysical null depth (or equivalently the object's visibility) in the presence of fast atmospheric fluctuations. The approach yields an accuracy much better (about an order of magnitude) than is presently possible with standard data reduction methods, because the astrophysical null depth accuracy is no longer limited by the magnitude of the instrumental phase and intensity errors but by uncertainties on their probability distributions. This approach was tested on the sky with the two-aperture fiber nulling instrument mounted on the Palomar Hale telescope. Using our new data analysis approach alone-and no observations of calibrators-we find that error bars on the astrophysical null depth as low as a few 10 -4 can be obtained in the near-infrared, which means that null depths lower than 10 -3 can be reliably measured. This statistical analysis is not specific to our instrument and may be applicable to other interferometers.

  16. The penetration depth and lateral distribution of pigment related to the pigment grain size and the calendering of paper

    International Nuclear Information System (INIS)

    Buelow, K.; Kristiansson, P.; Schueler, B.; Tullander, E.; Oestling, S.; Elfman, M.; Malmqvist, K.; Pallon, J.; Shariff, A.

    2002-01-01

    The interaction of ink and newspaper has been investigated and the specific question of penetration of ink into the paper has been addressed with a nuclear microprobe using particle induced X-ray emission. The penetration depth of the newsprint is a critical factor in terms of increasing the quality of newsprint and minimising the amount of ink used. The objective of the experiment was to relate the penetration depth of pigment with the calendering of the paper. The dependence of the penetration depth on the pigment grain size was also studied. To study the penetration depth of pigment in paper, cyan ink with Cu as a tracer of the coloured pigment was used. For the study of the penetration depth dependence of pigment size, specially grounded Japanese ink with well-defined pigment grain size was used. This was compared to Swedish ink with pigment grains with normal size-distribution. The results show that the calendering of the paper considerably affects the penetration depth of ink

  17. Accurate stopping power determination of 15N ions for hydrogen depth profiling by a combination of ion beams and synchrotron radiation

    Science.gov (United States)

    Zier, M.; Reinholz, U.; Riesemeier, H.; Radtke, M.; Munnik, F.

    2012-02-01

    Hydrogen analysis is of particular importance in thin film technology and it is often necessary to obtain a depth profile. The method with the best depth resolution is NRA using the 6385 keV resonance of the 1H( 15N,αγ) 12C nuclear reaction. The correct quantification of the depth and concentration scales in the measured hydrogen profiles relies on accurate stopping power values. We present a method to deduce these values from a combination of two techniques: NRA and X-ray reflectometry (XRR). This method is applied to the determination of the stopping power of ˜6.4 MeV 15N ions in H-containing amorphous Si-layers (a-Si:H). Density-independent stopping powers at different H concentrations are determined by combining the results from NRA and XRR with an overall uncertainty of 3.3%, showing good agreement with SRIM values. This work shows exemplary the methodology for future evaluation of stopping powers for quality assurance in NRA.

  18. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Börries, S., E-mail: stefan.boerries@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Metz, O.; Pranzas, P.K. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Bücherl, T. [ZTWB Radiochemie München (RCM), Technische Universität München (TUM), Walther-Meissner-Str. 3, D-85748 Garching (Germany); Söllradl, S. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII), Technische Universität München (TUM), Lichtenbergstr. 1, D-85748 Garching (Germany); Dornheim, M.; Klassen, T.; Schreyer, A. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany)

    2015-10-11

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail.

  19. Characterization of SCC crack tip and hydrogen distribution in alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Katsuhiko; Nakajima, Nobuo; Fukuya, Koji [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan); Hatano, Yuji [Toyama Univ. (Japan)

    2001-09-01

    In order to identify the mechanism of primary water stress corrosion cracking (SCC), direct observations of SCC crack tip microstructure and hydrogen distribution in alloy 600 were carried out. A new technique has been developed to prepare electron transparent foils including the crack tip using focused-ion beam (FIB) micro-processing technique. Cr-rich oxide and metal-Ni phase were identified in the crack tip and grain boundary ahead of the crack. >From the fact that similar microstructure was observed in the surface oxide layer, it is suggested that the oxidation mechanism is identical at the crack tip region and the surface. It became clear that the crack tip region and the oxidized grain boundary don't work as strong trapping sites of solute hydrogen under unloaded condition, because a homogeneous hydrogen distribution around the crack tip region was detected by tritium microautoradiography. (author)

  20. Depth distribution of Frank loop defects formed in ion-irradiated stainless steel and its dependence on Si addition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dongyue, E-mail: dychen@safety.n.t.u-tokyo.ac.jp [The University of Tokyo, Department of Nuclear Engineering and Management, School of Engineering, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8656 (Japan); Murakami, Kenta [The University of Tokyo, Nuclear Professional School, School of Engineering, 2-22 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1188 (Japan); Dohi, Kenji; Nishida, Kenji; Soneda, Naoki [Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komae, Tokyo 201-8511 (Japan); Li, Zhengcao, E-mail: zcli@tsinghua.edu.cn [Tsinghua University, School of Materials Science and Engineering, Beijing 100084 (China); Liu, Li; Sekimura, Naoto [The University of Tokyo, Department of Nuclear Engineering and Management, School of Engineering, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-12-15

    Although heavy ion irradiation is a good tool to simulate neutron irradiation-induced damages in light water reactor, it produces inhomogeneous defect distribution. Such difference in defect distribution brings difficulty in comparing the microstructure evolution and mechanical degradation between neutron and heavy ion irradiation, and thus needs to be understood. Stainless steel is the typical structural material used in reactor core, and could be taken as an example to study the inhomogeneous defect depth distribution in heavy ion irradiation and its influence on the tested irradiation hardening by nano-indentation. In this work, solution annealed stainless steel model alloys are irradiated by 3 MeV Fe{sup 2+} ions at 400 °C to 3 dpa to produce Frank loops that are mainly interstitial in nature. The silicon content of the model alloys is also tuned to change point defect diffusion, so that the loop depth distribution influenced by diffusion along the irradiation beam direction could be discussed. Results show that in low Si (0% Si) and base Si (0.42% Si) samples the depth distribution of Frank loop density quite well matches the dpa profile calculated by the SRIM code, but in high Si sample (0.95% Si), the loop number density in the near-surface region is very low. One possible explanation could be Si’s role in enhancing the effective vacancy diffusivity, promoting recombination and thus suppressing interstitial Frank loops, especially in the near-surface region, where vacancies concentrate. By considering the loop depth distribution, the tested irradiation hardening is successfully explained by the Orowan model. A hardening coefficient of around 0.30 is obtained for all the three samples. This attempt in interpreting hardening results may make it easier to compare the mechanical degradation between different irradiation experiments.

  1. Depth distribution of displacement damage in α-iron under triple beam ion irradiation

    International Nuclear Information System (INIS)

    Horton, L.L.; Bentley, J.; Jesser, W.A.

    1981-01-01

    The depth dependence of the defect structures was determined for iron irradiated at 850 0 K with 4 MeV Fe 2+ and energetic helium and deuteron ions to 10 dpa and fusion levels of helium and deuterium. From the damage profiles, a sectioning depth of 0.9 μm was selected for studies of iron and bcc iron alloys, such as ferritic steels, utilizing similar irradiation parameters. A comparison of the experimental damage profile to the deposited energy and deposited ion profiles calculated by E-DEP-1 indicated a possible overestimate of the LSS stopping power of at least 22%

  2. Efeito da profundidade de soldagem no hidrogênio difusível de soldas molhadas Effect of water depth on diffusible hydrogen on wet welds

    Directory of Open Access Journals (Sweden)

    Weslley Carlos Dias da Silva

    2012-12-01

    Full Text Available Em soldagem subaquática molhada, a ocorrência de poros e trincas a frio pode ter um efeito bastante prejudicial nas propriedades mecânicas da junta soldada. O hidrogênio contribui diretamente para o aparecimento destas duas descontinuidades. A quantidade de hidrogênio difusível (Hdif no metal de solda pode ser influenciada por diversos fatores. Todavia, pouco se sabe sobre a influência da profundidade de soldagem (pressão sobre a quantidade de Hdif no metal de solda. Neste trabalho, diversas medições de hidrogênio difusível foram feitas nas profundidades de 0,30 m, 10 m e 20 m e 30 m em soldagem molhada. O consumível utilizado foi o eletrodo comercial E6013 envernizado. As medições de hidrogênio difusível foram feitas através do método da cromatografia. Para medição de porosidade foi utilizado o método macrográfico e um programa analisador de imagem. O hidrogênio residual também foi medido. Os resultados mostraram que o hidrogênio difusível reduziu significativamente com o aumento da pressão hidrostática ao contrário da porosidade, que aumentou com o aumento da pressão hidrostática. Não se observou alterações apreciáveis no hidrogênio residual do metal de solda. Desta forma, é possível concluir que a profundidade de soldagem afeta diversos aspectos da soldagem subaquática molhada, em especial, o hidrogênio difusível e porosidade, conforme foi observado neste trabalho.In underwater wet welding, cold cracking and pores might have a deleterious effect in the mechanical properties of welded joint. The hydrogen might act in the occurrence of theses discontinuities. The amount of diffusible hydrogen in the weld metal can be influenced by several factors. However, not yet known whether the depth of welding (pressure affects the amount of diffusible hydrogen in weld metal. In this work, several measurements of diffusible hydrogen were made at following depth: 0.30 m, 10 m, 20 m and 30 m atwet welding. The

  3. Distribution of hydrogen-metabolizing bacteria in alfalfa field soil

    International Nuclear Information System (INIS)

    Cunningham, S.D.; Kapulnik, Y.; Phillips, D.A.

    1986-01-01

    H 2 evolved by alfalfa root nodules during the process of N 2 fixation may be an important factor influencing the distribution of soil bacteria. To test this hypothesis under field conditions, over 700 bacterial isolates were obtained from fallow soil or from the 3-mm layer of soil surrounding alfalfa (Medicago sativa L.) root nodules, alfalfa roots, or bindweed (Convolvulus arvensis L.) roots. Bacteria were isolated under either aerobic or microaerophilic conditions and were tested for their capacity to metabolize H 2 . Isolates showing net H 2 uptake and 3 H 2 incorporation activity under laboratory conditions were assigned a Hup + phenotype, whereas organisms with significant H 2 output capacity were designated as a Hout + phenotype. Under aerobic isolation conditions two Hup + isolates were obtained, whereas under microaerophilic conditions five Hup + and two Hout + isolates were found. The nine isolates differed on the basis of 24 standard bacteriological characteristics or fatty acid composition. Five of the nine organisms were isolated from soil around root nodules, whereas the other four were found distributed among the other three soil environments. On the basis of the microaerophilic isolations, 4.8% of the total procaryotic isolates from soil around root nodules were capable of oxidizing H 2 , and 1.2% could produce H 2 . Two of the Hup + isolates were identified as Rhizobium meliloti by root nodulation tests, but the fact that none of the isolates reduced C 2 H 2 under the assay conditions suggested that the H 2 metabolism traits were associated with various hydrogenase systems rather than with nitrogenase activity

  4. Deep-sea scleractinian coral age and depth distributions in the northwest Atlantic for the last 225,000 years

    Science.gov (United States)

    Robinson, L.F.; Adkins, J.F.; Scheirer, D.S.; Fernandez, D.P.; Gagnon, A.; Waller, R.G.

    2007-01-01

    Deep-sea corals have grown for over 200,000 yrs on the New England Seamounts in the northwest Atlantic, and this paper describes their distribution both with respect to depth and time. Many thousands of fossil scleractinian corals were collected on a series of cruises from 2003-2005; by contrast, live ones were scarce. On these seamounts, the depth distribution of fossil Desmophyllum dianthus (Esper, 1794) is markedly different to that of the colonial scleractinian corals, extending 750 m deeper in the water column to a distinct cut-off at 2500 m. This cut-off is likely to be controlled by the maximum depth of a notch-shaped feature in the seamount morphology. The ages of D. dianthus corals as determined by U-series measurements range from modern to older than 200,000 yrs. The age distribution is not constant over time, and most corals have ages from the last glacial period. Within the glacial period, increases in coral population density at Muir and Manning Seamounts coincided with times at which large-scale ocean circulation changes have been documented in the deep North Atlantic. Ocean circulation changes have an effect on coral distributions, but the cause of the link is not known. ?? 2007 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.

  5. Defect distribution in low-temperature molecular beam epitaxy grown Si/Si(100), improved depth profiling with monoenergetic positrons

    International Nuclear Information System (INIS)

    Szeles, C.; Asoka-Kumar, P.; Lynn, K.G.; Gossmann, H.; Unterwald, F.C.; Boone, T.

    1995-01-01

    The depth distribution of open-volume defects has been studied in Si(100) crystals grown by molecular beam epitaxy at 300 degree C by the variable-energy monoenergetic positron beam technique combined with well-controlled chemical etching. This procedure gave a 10 nm depth resolution which is a significant improvement over the inherent depth resolving power of the positron beam technique. The epitaxial layer was found to grow defect-free up to 80 nm, from the interface, where small vacancy clusters, larger than divacancies, appear. The defect density then sharply increases toward the film surface. The result clearly shows that the nucleation of small open-volume defects is a precursor state to the breakdown of epitaxy and to the evolution of an amorphous film

  6. Theoretical predictions of lactate and hydrogen ion distributions in tumours.

    Directory of Open Access Journals (Sweden)

    Maymona Al-Husari

    Full Text Available High levels of lactate and H(+-ions play an important role in the invasive and metastatic cascade of some tumours. We develop a mathematical model of cellular pH regulation focusing on the activity of the Na(+/H(+ exchanger (NHE and the lactate/H(+ symporter (MCT to investigate the spatial correlations of extracellular lactate and H(+-ions. We highlight a crucial role for blood vessel perfusion rates in determining the spatial correlation between these two cations. We also predict critical roles for blood lactate, the activity of the MCTs and NHEs on the direction of the cellular pH gradient in the tumour. We also incorporate experimentally determined heterogeneous distributions of the NHE and MCT transporters. We show that this can give rise to a higher intracellular pH and a lower intracellular lactate but does not affect the direction of the reversed cellular pH gradient or redistribution of protons away from the glycolytic source. On the other hand, including intercellular gap junction communication in our model can give rise to a reversed cellular pH gradient and can influence the levels of pH.

  7. Neutral Hydrogen Optical Depth near Star-forming Galaxies at z ≈ 2.4 in the Keck Baryonic Structure Survey

    Science.gov (United States)

    Rakic, Olivera; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.

    2012-06-01

    We study the interface between galaxies and the intergalactic medium by measuring the absorption by neutral hydrogen in the vicinity of star-forming galaxies at z ≈ 2.4. Our sample consists of 679 rest-frame UV-selected galaxies with spectroscopic redshifts that have impact parameters advantage of all available Lyman series lines. The median optical depth, and hence the median density of atomic hydrogen, drops by more than an order of magnitude around 100 kpc, which is similar to the virial radius of the halos thought to host the galaxies. The median remains enhanced, at the >3σ level, out to at least 2.8 Mpc (i.e., >9 comoving Mpc), but the scatter at a given distance is large compared with the median excess optical depth, suggesting that the gas is clumpy. Within 100 (200) kpc, and over ±165 km s-1, the covering fraction of gas with Lyα optical depth greater than unity is 100+0 - 32% (66% ± 16%). Absorbers with τLyα > 0.1 are typically closer to galaxies than random. The mean galaxy overdensity around absorbers increases with the optical depth and also as the length scale over which the galaxy overdensity is evaluated is decreased. Absorbers with τLyα ~ 1 reside in regions where the galaxy number density is close to the cosmic mean on scales >=0.25 Mpc. We clearly detect two types of redshift space anisotropies. On scales 3σ significance), an effect that we attribute to large-scale infall (i.e., the Kaiser effect). 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.

  8. Depth profile distribution of Cr, Cu, Co, Ni and Pb in the sediment cores of Mumbai Harbour Bay

    International Nuclear Information System (INIS)

    Madhuparna, D.; Hemalatha, P.; Raj, Sanu S.; Jha, S.K.; Tripathi, R.M.

    2014-01-01

    Estuarine and coastal sediments act as ultimate sink for trace metals that are discharged into the aquatic environment. Sources of environmental contaminants to the coastal system are numerous and may enter the estuarine environment via a number of pathways Mumbai Harbour Bay on the western coast of India, receives low level nuclear wastes and industrial and domestic sewage waste from the surrounding dwellings. Also, the bay is extensively exploited for various other local activities. The present study was carried out in the bay sediment cores to investigate the depth profile distribution of trace element concentration. Biologically significant toxic elements such as Cr, Cu, Co, Ni and Pb were estimated in the sediment cores to find out pattern of distribution in the sediment bed to follow the accumulation of elements with respect to depth

  9. Adjacent field separations for homogenous dose distribution at particular depth and associated hot and cold spots

    International Nuclear Information System (INIS)

    Supe, S.S.; Deka, A.C.; Deka, B.C.; Sathiyanaranyanan, V.K.

    1991-01-01

    In radiotherapy treatment planning we come across many situations when treatment is given by using two adjacent fields, for e.g. for treatment of Hodgkin's disease. A pair of adjacent field have been used regularly for the treatment of ovarian tumours. A small separation is given at the skin level, otherwise hot spots are observed at the depth of interest. The separation depend upon tumour depths, and source to skin distance (SSD). Formulae have been derived for the separation as well as for hot and cold spots. The case of adjacent field becomes more complicated when anterior as well as posterior adjacent fields are used. It is not completely possible to avoid the hot and cold spots in such cases. This is partially avoided by shifting the gap on the skin surface during the course of treatment. (author). 2 refs., 2 tabs

  10. Non destructive method of determination of depth profiling with ESCA spectroscopy by angular distribution

    International Nuclear Information System (INIS)

    Pijolat, Michele.

    1979-07-01

    The aim of this study has been to determine the possibilities of photoelectron spectroscopy ESCA for depth profiling in the first hundred angstrom of a compound. First of all, the technique ESCA has been described in an analytical point of view. Then, the common sputter profiling method has been tested, and a model to deduce the concentrations profile has been formulated. However the analysis of the various effects due to the sputtering events showed that this method is able to give only the profile shape with a bad depth resolution. A new non destructive method based on the analysed depth dependence with photoelectrons emission angle is settled. A computational method (simplexe optimization) is used to deduce the concentrations profile. Simulation have revealed the necessity of submitting constraints proper to the system physical properties and allowed to state the applicability range of the method. The interface profiles Ag-Pd, Ag-Al 2 O 3 and SiO 2 -Si have been measured, and the surface segregation in CuNi alloy has been studied [fr

  11. A method for determining the analytical form of a radionuclide depth distribution using multiple gamma spectrometry measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Steven Clifford, E-mail: sdewey001@gmail.com [United States Air Force School of Aerospace Medicine, Occupational Environmental Health Division, Health Physics Branch, Radiation Analysis Laboratories, 2350 Gillingham Drive, Brooks City-Base, TX 78235 (United States); Whetstone, Zachary David, E-mail: zacwhets@umich.edu [Radiological Health Engineering Laboratory, Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, 1906 Cooley Building, Ann Arbor, MI 48109-2104 (United States); Kearfott, Kimberlee Jane, E-mail: kearfott@umich.edu [Radiological Health Engineering Laboratory, Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, 1906 Cooley Building, Ann Arbor, MI 48109-2104 (United States)

    2011-06-15

    When characterizing environmental radioactivity, whether in the soil or within concrete building structures undergoing remediation or decommissioning, it is highly desirable to know the radionuclide depth distribution. This is typically modeled using continuous analytical expressions, whose forms are believed to best represent the true source distributions. In situ gamma ray spectroscopic measurements are combined with these models to fully describe the source. Currently, the choice of analytical expressions is based upon prior experimental core sampling results at similar locations, any known site history, or radionuclide transport models. This paper presents a method, employing multiple in situ measurements at a single site, for determining the analytical form that best represents the true depth distribution present. The measurements can be made using a variety of geometries, each of which has a different sensitivity variation with source spatial distribution. Using non-linear least squares numerical optimization methods, the results can be fit to a collection of analytical models and the parameters of each model determined. The analytical expression that results in the fit with the lowest residual is selected as the most accurate representation. A cursory examination is made of the effects of measurement errors on the method. - Highlights: > A new method for determining radionuclide distribution as a function of depth is presented. > Multiple measurements are used, with enough measurements to determine the unknowns in analytical functions that might describe the distribution. > The measurements must be as independent as possible, which is achieved through special collimation of the detector. > Although the effects of measurements errors may be significant on the results, an improvement over other methods is anticipated.

  12. Predictive modelling of habitat selection by marine predators with respect to the abundance and depth distribution of pelagic prey.

    Science.gov (United States)

    Boyd, Charlotte; Castillo, Ramiro; Hunt, George L; Punt, André E; VanBlaricom, Glenn R; Weimerskirch, Henri; Bertrand, Sophie

    2015-11-01

    Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. We analysed contemporaneous data on the diving locations of two seabird species, the shallow-diving Peruvian Booby (Sula variegata) and deeper diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique data set, we developed resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper water column. For both species, we show that the probability of diving behaviour is mostly explained by the distribution of prey at shallow depths. While the probability of diving behaviour increases sharply with prey abundance at relatively low levels of abundance, support for including abundance in addition to the depth distribution of prey is weak, suggesting that prey abundance was not a major factor determining the location of diving behaviour during the study period. The study thus highlights the importance of the depth distribution of prey for two species of seabird with different diving capabilities. The results complement previous research that points towards the importance of oceanographic processes that enhance the accessibility of prey to seabirds. The implications are that locations where prey is predictably found at accessible depths may be more important for surface foragers, such as seabirds, than locations where prey is predictably abundant. Analysis of the relative

  13. Dechanneling measurements of defect depth profiles and effective cross-channel distribution of misaligned atoms in ion irradiated gold

    International Nuclear Information System (INIS)

    Pronko, P.P.

    1975-01-01

    Defect depth profiles for self ion and He + irradiated gold are obtained from single and multiple scatter dechanneling analysis in single crystal gold films. Quantitative defect densities are obtained through use of atomic scattering cross sections. Integral damage profiles are extracted from the dechanneling spectra and subsequently differentiated to yield the volume concentration of defects as a function of depth. Results from the self ion irradiations suggest that incident ions produce defect distributions across depths much greater than predicted by random stopping theory. This is in agreement with TEM observations of others. Comparison of the experimental profiles is made with theoretical vacancy distributions predicted by defect diffusion in a radiation environment. Similarities are observed for the low fluence irradiations suggesting that profile characteristics may be controlled by rapid migration and loss of interstitials to the film surfaces during irradiation. Information on the across-channel distribution of misaligned atoms in the damaged films is obtained with the steady increase of transverse energy model applied to the dechanneling spectra. A predominance of slight misalignment is observed with no contribution to dechanneling coming from atoms displaced significantly close to the center of the channels. This is in keeping with what is expected for crystal distortions caused by the strain fields associated with vacancy cluster defects

  14. Distribution of meiobenthos at bathyal depths in the Mediterranean Sea. A comparison between sites of contrasting productivity

    Directory of Open Access Journals (Sweden)

    Anastasios Tselepides

    2004-12-01

    Full Text Available In order to study the distribution of meiobenthos (Metazoa and Foraminifera at bathyal depths along a west-east productivity gradient in the Mediterranean Sea, stations along the continental slopes of the Balearic Sea, west Ionian and east Ionian Seas were sampled during the DESEAS Trans-Mediterranean Cruise in June-July 2001. Standing stock of total meiobenthos differed considerably among the sampling stations, with marked differences occurring between sampling depths and sites. At 600 m depth, meiobenthic abundances were slightly higher over the Balearic continental slope, whereas at the deeper stations (800 m and 1500-1700 m, abundances were significantly higher in the west Ionian Sea. Significant relationships were found between the abundances of major groups and the chloroplastic pigments, indicating that food availability is a major factor controlling the distribution of meiobenthos. Apart from the overall differences in productivity between the western and eastern Mediterranean Sea, local hydrographic features and topographic differences greatly influence the spatial variability of the environmental parameters within each sub-basin and thus the distribution of meiobenthos in the bathyal zone.

  15. Dechanneling measurements of defect depth profiles and effective cross-channel distribution of misaligned atoms in ion-irradiated gold

    International Nuclear Information System (INIS)

    Pronko, P.P.

    1976-01-01

    Defect depth profiles for self-ion and He + irradiated gold are obtained from single and multiple scatter dechanneling analysis in single-crystal gold films. Quantitative defect densities are obtained through use of atomic-scattering cross sections. Integral damage profiles are extracted from the dechanneling spectra and subsequently differentiated to yield the volume concentration of defects as a function of depth. Results from the self-ion irradiations suggest that incident ions produce defect distributions across depths much greater than predicted by random stopping theory. This is in agreement with TEM observations of others. Comparison of the experimental profiles is made with theoretical vacancy distributions predicted by defect diffusion in a radiation environment. Similarities are observed for the low-fluence irradiations, suggesting that profile characteristics may be controlled by rapid migration and loss of interstitials to the film surfaces during irradiation. Information on the across-channel distribution of misaligned atoms in the damaged films is obtained with the steady increase of transverse energy model. A predominance of slight misalignment is observed with no contribution to dechanneling coming from atoms displaced significantly close to the center of the channels. This is in keeping with what is expected for crystal distortions caused by the strain fields associated with vacancy cluster defects. (Auth.)

  16. Breakdown transient study of plasma distributions in a 2.45 GHz hydrogen discharge

    Energy Technology Data Exchange (ETDEWEB)

    Cortázar, O.D., E-mail: daniel.cortazar@uclm.es [Universidad de Castilla-La Mancha, ETSII-INEI, Applied Mechanics and Projects Department, C.J. Cela s/n, 13170 Ciudad Real (Spain); Megía-Macías, A. [ESS Bilbao Consortium, Polígono Ugaldeguren-III Pol. A 7B, 48170-Zamudio, Vizcaya (Spain); Tarvainen, O.; Koivisto, H. [University of Jyväskylä, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2015-05-01

    Plasma distribution transients associated with the breakdown of a 2.45 GHz hydrogen discharge similar to high current microwave ion sources are studied by means of an ultra-fast frame image acquisition system in visible light range. Eight different plasma distributions have been studied by photographing the 2D projections of the discharge through a transparent plasma electrode. The temporal evolution of images in Balmer-alpha and Fulcher band wavelengths have been recorded associated to atomic and molecular excitation and ionization processes. Some unexpected plasma distributions transient behaviors during breakdown are reported.

  17. Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

    Directory of Open Access Journals (Sweden)

    Hongguang Cai

    2014-10-01

    Full Text Available A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen (N, phosphorus (P, and potassium (K uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development, increased nutrient accumulation, and increased yield. Compared with conventional soil management (CK, root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm (T1 and subsoil tillage to 50 cm (T2 were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the 12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments.

  18. Rail transportation by hydrogen vs. electrification - Case study for Ontario, Canada, II: Energy supply and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Marin, G.D.; Naterer, G.F.; Gabriel, K. [University of Ontario Institute of Technology, Faculty of Engineering and Applied Sciences, 2000 Simcoe Street North, Oshawa, Ontario (Canada)

    2010-06-15

    Locomotives offer an efficient mode of transportation when compared to buses, personal vehicles or airplanes for mass transportation over frequent intercity distances. For example, a Bombardier Regina EMU train with 272 seats and a load factor of 53% will consume under 0.07 kWh/passenger-km, which is typically much lower than corresponding values for other transportation modes in similar circumstances. European countries have invested significantly over the years in train electrification. Environmentally friendly methods of transferring power to the wheels are direct electrification and hydrogen fuel cells. Various methods to produce hydrogen for utilization with fuel cell train operation are examined in this paper. This companion paper of a 2-paper set examines the overall impact of energy supply (hydrogen vs. electricity) and distribution on rail transportation, specifically in terms of costs and overall GHG emissions for a case study of GO transit along the Lakeshore corridor in Toronto. Although electrification of train services simplifies some aspects of the operation, when considered over the Lakeshore corridor alone, electrified trains lose their flexibility to serve cities outside the Lakeshore corridor. Hydrogen fuelled trains can provide a smoother transition and interoperability by operating the same routes and stations served by diesel trains today, without being limited to the Lakeshore corridor. This paper evaluates technological, operational and economic aspects of the electrification of the Lakeshore corridor, versus hydrogen train operation, including infrastructure requirements to provide service to a substantial ridership increase projected for the years 2015-2031. Various methods of hydrogen production and distribution are presented and analysed, in order to evaluate the overall life cycle of GHG emissions and costs for various train alternatives. (author)

  19. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

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

  20. Spatial Interpolation of Aerosol Optical Depth Pollution: Comparison of Methods for the Development of Aerosol Distribution

    Science.gov (United States)

    Safarpour, S.; Abdullah, K.; Lim, H. S.; Dadras, M.

    2017-09-01

    Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters are important due to health impact. One widely available metric of aerosol abundance is the aerosol optical depth (AOD). The AOD is the integrated light extinction coefficient over a vertical atmospheric column of unit cross section, which represents the extent to which the aerosols in that vertical profile prevent the transmission of light by absorption or scattering. Seasonal aerosol optical depth (AOD) values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Terra satellites, for the 10 years period of 2000 - 2010 were used to test 7 different spatial interpolation methods in the present study. The accuracy of estimations was assessed through visual analysis as well as independent validation based on basic statistics, such as root mean square error (RMSE) and correlation coefficient. Based on the RMSE and R values of predictions made using measured values from 2000 to 2010, Radial Basis Functions (RBFs) yielded the best results for spring, summer and winter and ordinary kriging yielded the best results for fall.

  1. SPATIAL INTERPOLATION OF AEROSOL OPTICAL DEPTH POLLUTION: COMPARISON OF METHODS FOR THE DEVELOPMENT OF AEROSOL DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    S. Safarpour

    2017-09-01

    Full Text Available Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters are important due to health impact. One widely available metric of aerosol abundance is the aerosol optical depth (AOD. The AOD is the integrated light extinction coefficient over a vertical atmospheric column of unit cross section, which represents the extent to which the aerosols in that vertical profile prevent the transmission of light by absorption or scattering. Seasonal aerosol optical depth (AOD values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS sensor onboard NASA’s Terra satellites, for the 10 years period of 2000 - 2010 were used to test 7 different spatial interpolation methods in the present study. The accuracy of estimations was assessed through visual analysis as well as independent validation based on basic statistics, such as root mean square error (RMSE and correlation coefficient. Based on the RMSE and R values of predictions made using measured values from 2000 to 2010, Radial Basis Functions (RBFs yielded the best results for spring, summer and winter and ordinary kriging yielded the best results for fall.

  2. Simulations of hydrogen distribution experiments using the PRESCON2 and GOTHIC codes

    International Nuclear Information System (INIS)

    Nguyen, T.H.; Collins, W.M.

    1994-01-01

    The main objective of this work is to develop modelling guidelines in the use of containment models to more accurately predict hydrogen distribution in the HDR facility and to assess the ability of both lumped and distributed parameter models in predicting natural convective flows within containment. Experiences learned from this exercise will be applied to present methodologies used in licensing analyses for CANDU containments. PRESCON2 simulations of hydrogen distribution experiments performed in the HDR facility show hydrogen and helium concentrations are under-predicted at high elevations and over predicted at low elevations. Acceptable predictions of the gas concentration are obtained in the vicinity of the release. Results obtained from GOTHIC simulations using lumped parameter models are very comparable to those predicted by PRESCON2. This indicates that lumped parameter codes tend to over-estimate the degree of mixing of fluids due to the inherent nodal atmospheric homogeneity assumption in their numerical formulation. Results obtained from the GOTHIC simulation using a simple distributed parameter model show little improvement compared to those predicted using the lumped parameter model. This indicates that a simple 3-D model will not be sufficient to make significant improvements in the results. More detailed modelling of the junction flows and finer grids should lead to more accurate results. More detailed investigations employing finer 3-D meshes is under investigation. (author)

  3. Three-dimensional fuel pin model validation by prediction of hydrogen distribution in cladding and comparison with experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aly, A. [North Carolina State Univ., Raleigh, NC (United States); Avramova, Maria [North Carolina State Univ., Raleigh, NC (United States); Ivanov, Kostadin [Pennsylvania State Univ., University Park, PA (United States); Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Lacroix, E. [Pennsylvania State Univ., University Park, PA (United States); Manera, Annalisa [Univ. of Michigan, Ann Arbor, MI (United States); Walter, D. [Univ. of Michigan, Ann Arbor, MI (United States); Williamson, R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gamble, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-10-29

    To correctly describe and predict this hydrogen distribution there is a need for multi-physics coupling to provide accurate three-dimensional azimuthal, radial, and axial temperature distributions in the cladding. Coupled high-fidelity reactor-physics codes with a sub-channel code as well as with a computational fluid dynamics (CFD) tool have been used to calculate detailed temperature distributions. These high-fidelity coupled neutronics/thermal-hydraulics code systems are coupled further with the fuel-performance BISON code with a kernel (module) for hydrogen. Both hydrogen migration and precipitation/dissolution are included in the model. Results from this multi-physics analysis is validated utilizing calculations of hydrogen distribution using models informed by data from hydrogen experiments and PIE data.

  4. Determination of the columnar aerosol size distribution by inversion of spectral aerosol optical depth measurements at different areas in Egypt

    International Nuclear Information System (INIS)

    EI-Metwally, M.; Madkour, M.A.

    2006-01-01

    Aerosols have a great effects on nuclear safety calculations and atmospheric environment. The aerosol optical depth measurements are carried out at four areas in Egypt: Cairo and Helwan as urban/industrial areas, Aswan as an arid area and Mansoura as an agricultural area covering the period from Jun 1992 to May 1993. These measurements were recorded by ground-based pyrheliometers with large band-pass filters. Monthly average values of aerosol optical depth (AOD) showed a pronounced temporal trend, with a maximum AOD during summer and the transition seasons (spring and autumn) at all sites. Levels of AODs are higher at both urban and industrial areas than at other areas. Variation of Angstrom exponent a with the AOD was clear at most sites and the a value depends on the spectral range used in its determination. The mean contribution of anthropogenic sources to AOD over Cairo was at the range of 25.1-54.3%, whereas those values in Helwan were at the range of 34.5-59.8%. Finally, columnar aerosol size distributions have been inferred by inverting particularly AOD measurements as a function of wavelength. The Junge (type I) and bimodal (type III) distributions are dominant at urban and arid areas (Cairo and Aswan), whereas mono dispersion distribution (type II) are dominant in industrial and agricultural areas (Helwan and Mansoura). In Cairo and Aswan, the peak of columnar size distribution for the fine mode at radius r is around 0.1 and 0.2 μm respectively, while it is around 1.0 and 2.0 μm for the coarse mode. .Also, the peak of size distribution for the mono dispersion mode was marked at radius around 0.2 μm at both Helwan and Mansoura. A comprehensive comparison of our results with literature size distributions is very sparse, nevertheless, our size distributions in general agree with them

  5. Distribution and covering percentage of sponge (Porifera in different coral reef condition and depth in Barranglompo Island, South Sulawesi

    Directory of Open Access Journals (Sweden)

    SUHARYANTO

    2008-07-01

    Full Text Available In 1996, four specieses of sponge namely Auletta sp., Callyspongia pseudoreticulata, Callyspongia sp., and Halichondria sp. have been potentially identified as bacteriside for fishery commodities. Nevertheless, information on sponge distribution, its covering percentage, and its habitate are still very little. Observation on distribution and abundance of sponge was conducted in the Southeastern and the Northwestern part of Barranglompo Island, South Sulawesi, using scuba diving set and under water writting tools. At first, coral reef condition in 3 and 10 m depths up to 100 m length of shore line were observed in both stations, using “lifeform method”. Then distribution and covering percentage of sponge, biotic and abiotic factor in 3, 6, 9, and 12 m depths in both stations were examined using “square transect method”. The result showed that different coral reef condition qualitatively causes different of sponge species distribution, but quantitatively not significantly different (P>0,05 on its covering percentage. It was also found that generally sponge grows better at the dead coral where no other biotic organism around.

  6. Linking carbon and nitrogen metabolism to depth distribution of submersed macrophytes using high ammonium dosing tests and a lake survey.

    Science.gov (United States)

    Yuan, Guixiang; Cao, Te; Fu, Hui; Ni, Leyi; Zhang, Xiaolin; Li, Wei; Song, Xin; Xie, Ping; Jeppesen, Erik

    2013-12-01

    Strategies of carbon (C) and nitrogen (N) utilisation are among the factors determining plant distribution. It has been argued that submersed macrophytes adapted to lower light environments are more efficient in maintaining C metabolic homeostasis due to their conservative C strategy and ability to balance C shortage. We studied how depth distributions of 12 submersed macrophytes in Lake Erhai, China, were linked to their C-N metabolic strategies when facing acute [Formula: see text] dosing.[Formula: see text] dosing changed C-N metabolism significantly by decreasing the soluble carbohydrate (SC) content and increasing the [Formula: see text]-N and free amino acid (FAA) content of plant tissues.The proportional changes in SC contents in the leaves and FAA contents in the stems induced by [Formula: see text] dosing were closely correlated (positive for SC and negative for FAA) with the colonising water depths of the plants in Lake Erhai, the plants adapted to lower light regimes being more efficient in maintaining SC and FAA homeostasis.These results indicate that conservative carbohydrate metabolism of submersed macrophytes allowed the plants to colonise greater water depths in eutrophic lakes, where low light availability in the water column diminishes carbohydrate production by the plants.

  7. Fitness consequences of habitat variability, trophic position, and energy allocation across the depth distribution of a coral-reef fish

    Science.gov (United States)

    Goldstein, E. D.; D'Alessandro, E. K.; Sponaugle, S.

    2017-09-01

    Environmental clines such as latitude and depth that limit species' distributions may be associated with gradients in habitat suitability that can affect the fitness of an organism. With the global loss of shallow-water photosynthetic coral reefs, mesophotic coral ecosystems ( 30-150 m) may be buffered from some environmental stressors, thereby serving as refuges for a range of organisms including mobile obligate reef dwellers. Yet habitat suitability may be diminished at the depth boundary of photosynthetic coral reefs. We assessed the suitability of coral-reef habitats across the majority of the depth distribution of a common demersal reef fish ( Stegastes partitus) ranging from shallow shelf (SS, restrict foraging. Fish in MP environments had a broader diet niche, higher trophic position, and higher muscle C:N ratios compared to shallower environments. High C:N ratios suggest increased tissue lipid content in fish in MP habitats that coincided with higher investment in reproduction based on gonado-somatic index. These results suggest that peripheral MP reefs are suitable habitats for demersal reef fish and may be important refuges for organisms common on declining shallow coral reefs.

  8. Depth distribution of abiotic drivers of N mineralization and methane emission from a continuously and intermittently flooded Bangladeshi paddy soil

    Science.gov (United States)

    Akter, Masuda; Kader, Md. Abdul; Pierreux, Sofie; Boeckx, Pascal; Kamal, Ahammad Mostafa; Sleutel, Steven

    2016-04-01

    Water-saving irrigation such as AWD may significantly alter depth profiles of moisture content, pH, Eh and soil microbial activity. Modelling the effect of irrigation management on soil N mineralization, therefore requires detailed insight into depth distribution of these variables and dissolved organic carbon (DOC), and evolution of electron acceptors. We set up a field experiment at Bangladesh Agricultural University from January to May' 2015. The cultivated rice variety (BRRI dhan28) was grown under continuous flooding (CF) and alternate wetting and drying (AWD) management, with 120 kg N ha-1(N120) or without (N0)N fertilizer application. We measured soil mineral N and plant N uptake to evaluate N mineralization. CH4 emissions were monitored with timely gas sample collection and GC-analysis. Soil Eh at four depths and temperature at two depths were monitored continuously by Eh/T°-probes connected to a HYPNOS III data logger (MVH, The Netherlands). Simultaneously, soil solution from three depths were sampled with rhizon samplers to track DOC, Fe and Mn in solution. Over the growing season soil and air temperature increased by 8°C, and soil pH stayed near neutral (6.7 to 7.8). In all depths of AWD and CF, Eh dropped sharply to methanic conditions within 21 days after transplanting (DAT). Low redox-potential continued until 77DAT in all cases, except in the puddle layers under AWD, where redox raised to -200mV during drainage. Fe and Mn in soil solution increased gradually over the growing season, indicating continued reductive dissolution of Fe and Mn (hydro-)oxides. DOC increased continuously as well in all depths. Besides to release of DOC bound to pedogenic oxides upon their reductive dissolution, higher plant and soil microbial activity with increasing soil temperature (till 28°C) through the growing season explains the increasing DOC levels. Increasing methanogenic activity as indicated by the high CH4 emissions at 70-84DAT under both CF and AWD is

  9. Adaptation of spectral distribution of synchrotron radiation to X-ray depth lithography

    International Nuclear Information System (INIS)

    Maid, B.; Ehrfeld, W.; Hormes, J.; Mohr, J.; Muenchmeyer, D.

    1989-05-01

    Plastic microstructures with extremly high aspect ratios can be fabricated by X-ray depth lithography with synchrotron radiation. In order to minimize the expenditure in terms of irradiation the spectrum of the synchrotron radiation source has to be adapted to the irradiation task. It is characterized by the height of the microstructure and the maximum admissible dose ratio permitting the resist to develop in the depth without destruction of the surface as a result of radiation damage. Expenditure in terms of irradiation is minimum if an ideal sharp cutoff filter, profiting from the maximum permissible dose ratio, filters out the long-waved portion of the spectrum without attenuating the intensity of the short-waved portion of the spectrum. By the example of a typical resist-developer system the location of the filter edge was determined at different structural heights for the Bonn synchrotron and the ELSA electron stretching facility (Bonn). To be capable of building the ideal sharp cutoff filter, the thickness of an absorber was adapted for different materials in such a way that the maximum permissible dose ratio was obtained. If a thin reflector foil is used which is hit by glazing radiation, the expenditure in terms of irradiation can be reduced because of the steeper filter characteristic of resists with small maximum dose ratios. The short-waved transmitted beam is used for irradiation, with the filter edge set by the angle between the foil and the beam. The technical feasibility of a reflection filter was demonstrated on the model of a reflector foil consisting of 30 nm titanium on 7.5 μm polyimide substrate by transmission measurements performed at different angles. (orig./HP) [de

  10. CFD analyses of steam and hydrogen distribution in a nuclear power plant

    International Nuclear Information System (INIS)

    Siccama, N.B.; Houkema, M.; Komen, E.M.J.

    2003-01-01

    A detailed three-dimensional Computational Fluid Dynamics (CFD) model of the containment of the nuclear power plant has been prepared in order to assess possible multidimensional phenomena. In a first code-to-code comparison step, the CFD model has been used to compute a reference accident scenario which has been analysed earlier with the lumped parameter code SPECTRA. The CFD results compare qualitatively well with the SPECTRA results. Subsequently, the actual steam jet from the primary system has been modelled in the CFD code in order to determine the hydrogen distribution for this realistically modelled source term. Based on the computed hydrogen distributions, it has been determined when use of lumped parameter codes is allowed and when use of CFD codes is required. (author)

  11. Application of a CFD based containment model to different large-scale hydrogen distribution experiments

    International Nuclear Information System (INIS)

    Visser, D.C.; Siccama, N.B.; Jayaraju, S.T.; Komen, E.M.J.

    2014-01-01

    Highlights: • A CFD based model developed in ANSYS-FLUENT for simulating the distribution of hydrogen in the containment of a nuclear power plant during a severe accident is validated against four large-scale experiments. • The successive formation and mixing of a stratified gas-layer in experiments performed in the THAI and PANDA facilities are predicted well by the CFD model. • The pressure evolution and related condensation rate during different mixed convection flow conditions in the TOSQAN facility are predicted well by the CFD model. • The results give confidence in the general applicability of the CFD model and model settings. - Abstract: In the event of core degradation during a severe accident in water-cooled nuclear power plants (NPPs), large amounts of hydrogen are generated that may be released into the reactor containment. As the hydrogen mixes with the air in the containment, it can form a flammable mixture. Upon ignition it can damage relevant safety systems and put the integrity of the containment at risk. Despite the installation of mitigation measures, it has been recognized that the temporary existence of combustible or explosive gas clouds cannot be fully excluded during certain postulated accident scenarios. The distribution of hydrogen in the containment and mitigation of the risk are, therefore, important safety issues for NPPs. Complementary to lumped parameter code modelling, Computational Fluid Dynamics (CFD) modelling is needed for the detailed assessment of the hydrogen risk in the containment and for the optimal design of hydrogen mitigation systems in order to reduce this risk as far as possible. The CFD model applied by NRG makes use of the well-developed basic features of the commercial CFD package ANSYS-FLUENT. This general purpose CFD package is complemented with specific user-defined sub-models required to capture the relevant thermal-hydraulic phenomena in the containment during a severe accident as well as the effect of

  12. Application of a CFD based containment model to different large-scale hydrogen distribution experiments

    Energy Technology Data Exchange (ETDEWEB)

    Visser, D.C., E-mail: visser@nrg.eu; Siccama, N.B.; Jayaraju, S.T.; Komen, E.M.J.

    2014-10-15

    Highlights: • A CFD based model developed in ANSYS-FLUENT for simulating the distribution of hydrogen in the containment of a nuclear power plant during a severe accident is validated against four large-scale experiments. • The successive formation and mixing of a stratified gas-layer in experiments performed in the THAI and PANDA facilities are predicted well by the CFD model. • The pressure evolution and related condensation rate during different mixed convection flow conditions in the TOSQAN facility are predicted well by the CFD model. • The results give confidence in the general applicability of the CFD model and model settings. - Abstract: In the event of core degradation during a severe accident in water-cooled nuclear power plants (NPPs), large amounts of hydrogen are generated that may be released into the reactor containment. As the hydrogen mixes with the air in the containment, it can form a flammable mixture. Upon ignition it can damage relevant safety systems and put the integrity of the containment at risk. Despite the installation of mitigation measures, it has been recognized that the temporary existence of combustible or explosive gas clouds cannot be fully excluded during certain postulated accident scenarios. The distribution of hydrogen in the containment and mitigation of the risk are, therefore, important safety issues for NPPs. Complementary to lumped parameter code modelling, Computational Fluid Dynamics (CFD) modelling is needed for the detailed assessment of the hydrogen risk in the containment and for the optimal design of hydrogen mitigation systems in order to reduce this risk as far as possible. The CFD model applied by NRG makes use of the well-developed basic features of the commercial CFD package ANSYS-FLUENT. This general purpose CFD package is complemented with specific user-defined sub-models required to capture the relevant thermal-hydraulic phenomena in the containment during a severe accident as well as the effect of

  13. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

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

  14. Hydrogen distribution analysis for CANDU 6 containment using the GOTHIC containment analysis code

    International Nuclear Information System (INIS)

    Nguyen, T.H.; Collins, W.M.

    1995-01-01

    Hydrogen may be generated in the reactor core by the zircaloy-steam reaction for a postulated loss of coolant accident (LOCA) scenario with loss of emergency core cooling (ECC). It is important to predict hydrogen distribution within containment in order to determine if flammable mixtures exist. This information is required to determine the best locations in containment for the placement of mitigation devices such as igniters and recombiners. For large break loss coolant accidents, hydrogen is released after the break flow has subsided. Following this period of high discharge the flow in the containment building undergoes transition from forced flow to a buoyancy driven flow (particularly when local air coolers (LACS) are not credited). One-dimensional computer codes (lumped parameter) are applicable during the initial period when a high degree of mixing occurs due to the forced flow generated by the break. However, during the post-blowdown phase the assumption of homogeneity becomes less accurate, and it is necessary to employ three-dimensional codes to capture local effects. This is particularly important for purely buoyant flows which may exhibit stratification effects. In the present analysis a three-dimensional model of CANDU 6 containment was constructed with the GOTHIC computer code using a relatively coarse mesh adequate enough to capture the salient features of the flow during the blowdown and hydrogen release periods. A 3D grid representation was employed for that portion of containment in which the primary flow (LOCA and post-LOCA) was deemed to occur. The remainder of containment was represented by lumped nodes. The results of the analysis indicate that flammable concentrations exist for several minutes in the vicinity of the break and in the steam generator enclosure. This is due to the fact that the hydrogen released from the break is primarily directed upwards into the steam generator enclosure due to buoyancy effects. Once hydrogen production ends

  15. Distributed Video Coding for Multiview and Video-plus-depth Coding

    DEFF Research Database (Denmark)

    Salmistraro, Matteo

    The interest in Distributed Video Coding (DVC) systems has grown considerably in the academic world in recent years. With DVC the correlation between frames is exploited at the decoder (joint decoding). The encoder codes the frame independently, performing relatively simple operations. Therefore......, with DVC the complexity is shifted from encoder to decoder, making the coding architecture a viable solution for encoders with limited resources. DVC may empower new applications which can benefit from this reversed coding architecture. Multiview Distributed Video Coding (M-DVC) is the application...... of the to-be-decoded frame. Another key element is the Residual estimation, indicating the reliability of the SI, which is used to calculate the parameters of the correlation noise model between SI and original frame. In this thesis new methods for Inter-camera SI generation are analyzed in the Stereo...

  16. Quality parameters analysis of optical imaging systems with enhanced focal depth using the Wigner distribution function

    Science.gov (United States)

    Zalvidea; Colautti; Sicre

    2000-05-01

    An analysis of the Strehl ratio and the optical transfer function as imaging quality parameters of optical elements with enhanced focal length is carried out by employing the Wigner distribution function. To this end, we use four different pupil functions: a full circular aperture, a hyper-Gaussian aperture, a quartic phase plate, and a logarithmic phase mask. A comparison is performed between the quality parameters and test images formed by these pupil functions at different defocus distances.

  17. Observations of distributed snow depth and snow duration within diverse forest structures in a maritime mountain watershed

    Science.gov (United States)

    Dickerson-Lange, Susan E.; Lutz, James A.; Gersonde, Rolf; Martin, Kael A.; Forsyth, Jenna E.; Lundquist, Jessica D.

    2015-11-01

    Spatially distributed snow depth and snow duration data were collected over two to four snow seasons during water years 2011-2014 in experimental forest plots within the Cedar River Municipal Watershed, 50 km east of Seattle, Washington, USA. These 40 × 40 m forest plots, situated on the western slope of the Cascade Range, include unthinned second-growth coniferous forests, variable density thinned forests, forest gaps in which a 20 m diameter (approximately equivalent to one tree height) gap was cut in the middle of each plot, and old-growth forest. Together, this publicly available data set includes snow depth and density observations from manual snow surveys, distributed snow duration observations from ground temperature sensors and time-lapse cameras, meteorological data collected at two open locations and three forested locations, and forest canopy data from airborne light detection and ranging (LiDAR) data and hemispherical photographs. These colocated snow, meteorological, and forest data have the potential to improve understanding of forest influences on snow processes, and provide a unique model-testing data set for hydrological analyses in a forested, maritime watershed. We present empirical snow depletion curves within forests to illustrate an application of these data to improve subgrid representation of snow cover in distributed modeling.

  18. Determining global distribution of microplastics by combining citizen science and in-depth case studies.

    Science.gov (United States)

    Bosker, Thijs; Behrens, Paul; Vijver, Martina G

    2017-05-01

    Microplastics (microplastics levels. The difference in extraction procedures can especially impact study outcomes, making it difficult, and sometimes impossible, to directly compare results among studies. To address this, we recently developed a standard operating procedure (SOP) for sampling microplastics on beaches. We are now assessing regional and global variations in beach microplastics using this standardized approach for 2 research projects. Our first project involves the general public through citizen science. Participants collect sand samples from beaches using a basic protocol, and we subsequently extract and quantify microplastics in a central laboratory using the SOP. Presently, we have 80+ samples from around the world and expect this number to further increase. Second, we are conducting 2, in-depth, regional case studies: one along the Dutch coast (close to major rivers, a known source of microplastic input into marine systems), and the other on the Lesser Antilles in the Caribbean (in the proximity to a hotspot of plastics in the North Atlantic Ocean). In both projects, we use our new SOP to determine regional variation in microplastics, including differences in physicochemical characteristics such as size, shape, and polymer type. Our research will provide, for the first time, a systematic comparison on levels of microplastics on beaches at both a regional and global scale. Integr Environ Assess Manag 2017;13:536-541. © 2017 SETAC. © 2017 SETAC.

  19. Depth distribution of carrier lifetime in 65 MeV oxygen ion irradiated silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, N.S. [Ecotopia Science Institute, Division of Energy Science, Nagoya University, Nagoya (Japan); Dahiwale, S.S. [Department of Physics, University of Pune, Pune 411 007 (India); Kanjilal, D. [Nuclear Science Centre, New Delhi (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411 007 (India)]. E-mail: sanjay@physics.unipune.ernet.in

    2006-03-15

    CZ-grown, n-doped crystalline Si(1 1 1) of resistivity 60 {omega} cm and 140 {omega} cm were irradiated with 65 MeV energy oxygen ions, in the fluence range of 2 x 10{sup 1}-10{sup 14} ions/cm{sup 2}. The depth and spatial profile of excess minority carrier recombination time {tau} (lifetime) was measured using photoconductive decay (PCD) method. Lifetime measurements were carried out before the stopping range of impinging ions. Results show a monotonous decrease in lifetime with fluence, which is attributed to defect creation mechanism by electronic energy loss based on the thermal spike model. Also, surface modification is expected with a small loss in crystalline quality. This surface is considered to be a multi-crystalline surface with large grain boundaries that act as trapping sites for excess holes in n-Si(1 1 1). Annealing of the irradiated samples showed a near complete recovery at 750 deg. C for a period of 1 h.

  20. Depth distribution of radiocesium in Fukushima paddy fields and implications for ongoing decontamination works

    Science.gov (United States)

    Lepage, H.; Evrard, O.; Onda, Y.; Lefèvre, I.; Laceby, J. P.; Ayrault, S.

    2014-09-01

    Large quantities of radiocesium were deposited across a 3000 km2 area northwest of the Fukushima Dai-ichi nuclear power plant after the March 2011 accident. Although many studies have investigated the fate of radiocesium in soil in the months following the accident, the potential migration of this radioactive contaminant in rice paddy fields requires further examination after the typhoons that occurred in this region. Such investigations will help minimize potential human exposure in rice paddy fields or transfer of radioactive contaminants from soils to rice. Radionuclide activity concentrations and organic content were analysed in 10 soil cores sampled from paddy fields in November 2013, 20 km north of the Fukushima power plant. Our results demonstrate limited depth migration of radiocesium with the majority concentrated in the uppermost layers of soils (accident, 81.5 to 99.7% of the total 137Cs inventories was still found within the works may increase soil erodibility. We therefore recommend the rapid removal of the uppermost - contaminated - layer of the soil after removing the vegetation to avoid erosion of contaminated material during the subsequent rainfall events. Remediation efforts should be concentrated on soils characterised by radiocesium activities > 10 000 Bq kg-1 to prevent the contamination of rice. Further analysis is required to clarify the redistribution of radiocesium eroded on river channels.

  1. Depth distribution of bubbles in 4He+-ion irradiated nickel and the mechanism of blister formation

    International Nuclear Information System (INIS)

    Fenske, G.; Das, S.K.; Kaminsky, M.; Miley, G.H.

    1978-01-01

    While the radiation blistering phenomenon has been widely studied, the mechanism of blister formation is still not well understood. The present studies on depth distribution of helium bubbles in nickel were carried out in order to obtain a better understanding of the radiation blistering process. Particularly, the aim was to understand the experimental observation that the blister skin thickness for many metals irradiated with He + ions of energies lower than 20-keV is a factor of two or more larger than the calculated projected range. (Auth.)

  2. Application of the resonant 52(p,γ)53Mn reaction to the measurement of chromium depth distributions

    International Nuclear Information System (INIS)

    Switkowski, Z.E.; Petty, R.J.; Clark, G.J.

    1979-01-01

    A resonance in the 52 Cr(p,γ) 53 Mn reaction has been investigated as a probe for the quantitative determination of chromium depth distributions. The relevant nuclear parameters of this resonance were measured to be: resonance energy, Esub(p)1005.2 +- 0.2 keV, total width GAMMA < 100 eV, and resonance strength, (2J+1)GAMMAsub(p)GAMMAsub(γ)/GAMMA = 0.89 +-0.11 eV. As an example of the use of the nuclear resonance technique, the chromium profile of an electroplated chrome black solar absorber surface has been studied and the results are presented

  3. Emission depth distribution function of Al 2s photoelectrons in Al.sub.2./sub.O.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Hucek, Stanislav; Zemek, Josef; Jablonski, A.; Tilinin, L. S.

    2000-01-01

    Roč. 7, 1&2 (2000), s. 109-114 ISSN 0218-625X R&D Projects: GA ČR GA202/95/0032 Grant - others:GA UK(CZ) 33 Institutional research plan: CEZ:AV0Z6022909; CEZ:AV0Z1010914 Keywords : depth distribution function * DDF * Monte Carlo simulation * Beer - Lambert law * Boltzmann kinetic equation * straight line approximation * SLA Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.886, year: 2000

  4. The formation of molecular hydrogen on silicate dust analogs: The rotational distribution

    Energy Technology Data Exchange (ETDEWEB)

    Gavilan, L.; Lemaire, J. L. [LERMA, UMR 8112 du CNRS, de l' Observatoire de Paris et de l' Université de Cergy Pontoise, 5 mail Gay Lussac, F-95000 Cergy Pontoise Cedex (France); Vidali, G. [Visiting Professor. Permanent address: Syracuse University, Physics Department, Syracuse, NY 13244-1320, USA. (United States); Sabri, T.; Jæger, C., E-mail: lisseth.gavilan@obspm.fr [Laboratory Astrophysics and Cluster Physics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena (Germany)

    2014-02-01

    Our laboratory experiments continue to explore how the formation of molecular hydrogen is influenced by dust and how dust thereby affects hydrogen molecules adsorbed on its surface. In Sabri et al., we present the preparation of nanometer-sized silicate grain analogs via laser ablation. These analogs illustrate extremes in structure (fully crystalline or fully amorphous grains), and stoichiometry (the forsterite and fayalite end-members of the olivine family). These were inserted in FORMOLISM, an ultra-high vacuum setup where they can be cooled down to ∼5 K. Atomic beams are directed at these surfaces and the formation of new molecules is studied via REMPI(2+1) spectroscopy. We explored the rotational distribution (0 ≤ J'' ≤ 5) of v'' = 0 of the ground electronic state of H{sub 2}. The results of these measurements are reported here. Surprisingly, molecules formed and ejected from crystalline silicates have a cold (T {sub rot} ∼ 120 K) rotational energy distribution, while for molecules formed on and ejected from amorphous silicate films, the rotational temperature is ∼310 K. These results are compared to previous experiments on metallic surfaces and theoretical simulations. Solid-state surface analysis suggests that flatter grains could hinder the 'cartwheel' rotation mode. A search for hot hydrogen, predicted as a result of H{sub 2} formation, hints at its production. For the first time, the rotational distribution of hydrogen molecules formed on silicate dust is reported. These results are essential to understanding the chemistry of astrophysical media containing bare dust grains.

  5. Thermal neutron diffusion parameters dependent on the flux energy distribution in finite hydrogenous media

    International Nuclear Information System (INIS)

    Drozdowicz, K.

    1999-01-01

    Macroscopic parameters for a description of the thermal neutron transport in finite volumes are considered. A very good correspondence between the theoretical and experimental parameters of hydrogenous media is attained. Thermal neutrons in the medium possess an energy distribution, which is dependent on the size (characterized by the geometric buckling) and on the neutron transport properties of the medium. In a hydrogenous material the thermal neutron transport is dominated by the scattering cross section which is strongly dependent on energy. A monoenergetic treatment of the thermal neutron group (admissible for other materials) leads in this case to a discrepancy between theoretical and experimental results. In the present paper the theoretical definitions of the pulsed thermal neutron parameters (the absorption rate, the diffusion coefficient, and the diffusion cooling coefficient) are based on Nelkin's analysis of the decay of a neutron pulse. Problems of the experimental determination of these parameters for a hydrogenous medium are discussed. A theoretical calculation of the pulsed parameters requires knowledge of the scattering kernel. For thermal neutrons it is individual for each hydrogenous material because neutron scattering on hydrogen nuclei bound in a molecule is affected by the molecular dynamics (characterized with internal energy modes which are comparable to the incident neutron energy). Granada's synthetic model for slow-neutron scattering is used. The complete up-dated formalism of calculation of the energy transfer scattering kernel after this model is presented in the paper. An influence of some minor variants within the model on the calculated differential and integral neutron parameters is shown. The theoretical energy-dependent scattering cross section (of Plexiglas) is compared to experimental results. A particular attention is paid to the calculation of the diffusion cooling coefficient. A solution of an equation, which determines the

  6. Degradation of proton depth dose distributions attributable to microstructures in lung-equivalent material

    Energy Technology Data Exchange (ETDEWEB)

    Titt, Uwe, E-mail: utitt@mdanderson.org; Mirkovic, Dragan; Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Sell, Martin [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Department of Medical Physics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Unkelbach, Jan [Department of Radiation Oncology, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114 (United States); Bangert, Mark [Department of Medical Physics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Oelfke, Uwe [Department of Medical Physics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany and Department of Physics, The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP (United Kingdom)

    2015-11-15

    Purpose: The purpose of the work reported here was to investigate the influence of sub-millimeter size heterogeneities on the degradation of the distal edges of proton beams and to validate Monte Carlo (MC) methods’ ability to correctly predict such degradation. Methods: A custom-designed high-resolution plastic phantom approximating highly heterogeneous, lung-like structures was employed in measurements and in Monte Carlo simulations to evaluate the degradation of proton Bragg curves penetrating heterogeneous media. Results: Significant differences in distal falloff widths and in peak dose values were observed in the measured and the Monte Carlo simulated curves compared to pristine proton Bragg curves. Furthermore, differences between simulations of beams penetrating CT images of the phantom did not agree well with the corresponding experimental differences. The distal falloff widths in CT image-based geometries were underestimated by up to 0.2 cm in water (corresponding to 0.8–1.4 cm in lung tissue), and the peak dose values of pristine proton beams were overestimated by as much as ~35% compared to measured curves or depth-dose curves simulated on the basis of true geometry. The authors demonstrate that these discrepancies were caused by the limited spatial resolution of CT images that served as a basis for dose calculations and lead to underestimation of the impact of the fine structure of tissue heterogeneities. A convolution model was successfully applied to mitigate the underestimation. Conclusions: The results of this study justify further development of models to better represent heterogeneity effects in soft-tissue geometries, such as lung, and to correct systematic underestimation of the degradation of the distal edge of proton doses.

  7. Degradation of proton depth dose distributions attributable to microstructures in lung-equivalent material

    International Nuclear Information System (INIS)

    Titt, Uwe; Mirkovic, Dragan; Mohan, Radhe; Sell, Martin; Unkelbach, Jan; Bangert, Mark; Oelfke, Uwe

    2015-01-01

    Purpose: The purpose of the work reported here was to investigate the influence of sub-millimeter size heterogeneities on the degradation of the distal edges of proton beams and to validate Monte Carlo (MC) methods’ ability to correctly predict such degradation. Methods: A custom-designed high-resolution plastic phantom approximating highly heterogeneous, lung-like structures was employed in measurements and in Monte Carlo simulations to evaluate the degradation of proton Bragg curves penetrating heterogeneous media. Results: Significant differences in distal falloff widths and in peak dose values were observed in the measured and the Monte Carlo simulated curves compared to pristine proton Bragg curves. Furthermore, differences between simulations of beams penetrating CT images of the phantom did not agree well with the corresponding experimental differences. The distal falloff widths in CT image-based geometries were underestimated by up to 0.2 cm in water (corresponding to 0.8–1.4 cm in lung tissue), and the peak dose values of pristine proton beams were overestimated by as much as ~35% compared to measured curves or depth-dose curves simulated on the basis of true geometry. The authors demonstrate that these discrepancies were caused by the limited spatial resolution of CT images that served as a basis for dose calculations and lead to underestimation of the impact of the fine structure of tissue heterogeneities. A convolution model was successfully applied to mitigate the underestimation. Conclusions: The results of this study justify further development of models to better represent heterogeneity effects in soft-tissue geometries, such as lung, and to correct systematic underestimation of the degradation of the distal edge of proton doses

  8. Depth distribution of glyphosate and organic matter after 5 years of agroecology transition compared with industrial agriculture

    Science.gov (United States)

    Aparicio, Virginia; Zamora, Martin; Barbera, Agustin; Castro Franco, Mauricio; Domenech, Marisa; De Geronimo, Eduardo; Costa, Jose Luis

    2017-04-01

    The industrial model of agriculture, defined here by its capital intensity and dependence on massive inputs like seeds, fertilizer, and pesticides, is reducing soil organic matter and increasing the inefficiency in agrochemical used. Ecological impacts of industrial agriculture include pollution by pesticides, soil organic matter loss and soil degradation, among many others, with the consequent human health risks. Many of the negative effects of industrial agriculture are remote from fields and farms. The impacts of industrial agriculture on the environment, public health, and rural communities make it an unsustainable way to grow our food over the long term. An alternative approach to the industrial agriculture is the agroecology which has shown promising success on the ground and is actually the only way to ensure that all people have access to sufficient, healthful food. Farming systems designed and managed according to ecological principles can meet the food needs of society while addressing these pressing environmental and social issues. Our concept of agroecological transition is based on increasing resource use efficiency (e.g. fertilizer, pesticides and water), recycling waste or byproducts of one subsystem in another and applying sound? agricultural practices or precision-agriculture technologies. The objective of this work was to compare two production systems: a) industrial agriculture, b) agroecological transition with respect to the impact on the glyphosate load and the organic matter content in the soil and its distribution in depth. The study sites were two field of 15 ha each located at Barrow Experimental Station (38°19´S, 60°15´W). Soil ECa mapping was carried out and the complete experimental area was divided in three ECa classes with similar soil characteristics. Therefore, soil sampling was carried out by zones, based on three ECa classes at each production systems. Soil samples were taken at 0-2, 2-5, 5-10, 10-20, 20-30 and 30-40 cm depth

  9. Crystal orientation effects on helium ion depth distributions and adatom formation processes in plasma-facing tungsten

    International Nuclear Information System (INIS)

    Hammond, Karl D.; Wirth, Brian D.

    2014-01-01

    We present atomistic simulations that show the effect of surface orientation on helium depth distributions and surface feature formation as a result of low-energy helium plasma exposure. We find a pronounced effect of surface orientation on the initial depth of implanted helium ions, as well as a difference in reflection and helium retention across different surface orientations. Our results indicate that single helium interstitials are sufficient to induce the formation of adatom/substitutional helium pairs under certain highly corrugated tungsten surfaces, such as (1 1 1)-orientations, leading to the formation of a relatively concentrated layer of immobile helium immediately below the surface. The energies involved for helium-induced adatom formation on (1 1 1) and (2 1 1) surfaces are exoergic for even a single adatom very close to the surface, while (0 0 1) and (0 1 1) surfaces require two or even three helium atoms in a cluster before a substitutional helium cluster and adatom will form with reasonable probability. This phenomenon results in much higher initial helium retention during helium plasma exposure to (1 1 1) and (2 1 1) tungsten surfaces than is observed for (0 0 1) or (0 1 1) surfaces and is much higher than can be attributed to differences in the initial depth distributions alone. The layer thus formed may serve as nucleation sites for further bubble formation and growth or as a source of material embrittlement or fatigue, which may have implications for the formation of tungsten “fuzz” in plasma-facing divertors for magnetic-confinement nuclear fusion reactors and/or the lifetime of such divertors.

  10. Tracking Electroencephalographic Changes Using Distributions of Linear Models: Application to Propofol-Based Depth of Anesthesia Monitoring.

    Science.gov (United States)

    Kuhlmann, Levin; Manton, Jonathan H; Heyse, Bjorn; Vereecke, Hugo E M; Lipping, Tarmo; Struys, Michel M R F; Liley, David T J

    2017-04-01

    Tracking brain states with electrophysiological measurements often relies on short-term averages of extracted features and this may not adequately capture the variability of brain dynamics. The objective is to assess the hypotheses that this can be overcome by tracking distributions of linear models using anesthesia data, and that anesthetic brain state tracking performance of linear models is comparable to that of a high performing depth of anesthesia monitoring feature. Individuals' brain states are classified by comparing the distribution of linear (auto-regressive moving average-ARMA) model parameters estimated from electroencephalographic (EEG) data obtained with a sliding window to distributions of linear model parameters for each brain state. The method is applied to frontal EEG data from 15 subjects undergoing propofol anesthesia and classified by the observers assessment of alertness/sedation (OAA/S) scale. Classification of the OAA/S score was performed using distributions of either ARMA parameters or the benchmark feature, Higuchi fractal dimension. The highest average testing sensitivity of 59% (chance sensitivity: 17%) was found for ARMA (2,1) models and Higuchi fractal dimension achieved 52%, however, no statistical difference was observed. For the same ARMA case, there was no statistical difference if medians are used instead of distributions (sensitivity: 56%). The model-based distribution approach is not necessarily more effective than a median/short-term average approach, however, it performs well compared with a distribution approach based on a high performing anesthesia monitoring measure. These techniques hold potential for anesthesia monitoring and may be generally applicable for tracking brain states.

  11. Direct observation of the hydrogen peak in the energy distribution of electrons backscattered elastically from polyethylene

    International Nuclear Information System (INIS)

    Varga, D.; Toekesi, K.; Berenyi, Z.; Toth, J.; Koever, L.

    2004-01-01

    Complete text of publication follows. Observation of the hydrogen peak is either challenging or impossible task for the conventional electron spectroscopy. Hydrogen was observed earlier in electron scattering experiments using transmission geometry and formvar film. In this work we show an alternative way for the detection of hydrogen peak analyzing the spectra of elastically backscattered electrons from polyethylene ((CH 2 ) n ). We take advantage of the fact that the elastic peak from polyethylene split into carbon and hydrogen components. The energy of the elastically scattered electrons is shifted from the nominal values due to the energy transfer between the primary electron and the target atoms (recoil effect). Due to the motion of the scattering atoms, a broadering of the energy width of the spectra takes place. We performed Monte Carlo simulation for 2 keV electrons penetrated and elastically backscattered from polyethylene sample. In our calculations both the elastic and inelastic scattering events were taken into account. We further assume that the thermal motion of the target atoms follows the Maxwell-Boltzmann energy distribution. After each elastic scattering the recoil energy was calculated according to ref Fig. 1 shows the geometric configuration used in the calculation. The initial angle of incident beam (θ) was 50 deg. Fig. 2 shows the gray scale plot of the intensity of electrons backscattered elastically from polyethylene. The separation between the carbon and hydrogen peaks is clearly seen. Our results show that the multiple electron scattering causes only minor changes in the energy shifts and broadenings of elastic peaks. Moreover, our simulations are in good agreement with our experimental observations. (author)

  12. Measurements of nitrogen depth distribution in the surface of steel with the 14N(d,p0)15N reaction

    International Nuclear Information System (INIS)

    Didriksson, R.; Goenczi, L.; Sundqvist, B.

    1980-01-01

    The 14 N(d,p 0 ) 15 N nuclear reaction has been used to measure the nitrogen depth distribution in the surface of steel samples. With a beam energy of 2.5 MeV a depth of 15μm could be analyzed. The depth resolution was 0.7 μm (FWHM) and nitrogen contents down to 0.02 percent could be determined. (author)

  13. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions

    NARCIS (Netherlands)

    Ingerle, D.; Meirer, F.; Pepponi, G.; Demenev, E.; Giubertoni, D.; Wobrauschek, P.; Streli, C.

    2014-01-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and

  14. Ejected electron energy distribution in the ionization of atomic hydrogen by C6+ impact

    International Nuclear Information System (INIS)

    Dey, Ritu; Roy, A.C.

    2006-01-01

    We report doubly differential cross section (DDCS) for C 6+ impact ionization of atomic hydrogen at the incident energy of 2.5 MeV/amu. The calculation is based on the eikonal approximation (EA) method. A comparison is made of the present DDCS with the results of other theoretical methods and experiment. It is found that the multiple scattering effect has a significant influence on the energy distributions of the ejected electrons. The cross sections predicted by the present EA also show reasonably good agreement with experiment

  15. Cell size spatial convergence analysis on GOTHIC distributed parameter models for studying hydrogen mixing behaviour in CANDU containments

    International Nuclear Information System (INIS)

    Yim, K.; Wong, R.C.

    1995-01-01

    Gas mixing phenomena can be modelled using distributed parameter codes such as GOTHIC, but the selection of the optimum cell size is an important user input. The tradeoff between accuracy and practical computation times affect the choice of cell sizes, where small cells provide better accuracy at the expense of longer computing time. A study on cell size effect on hydrogen distribution is presented for the problem of hydrogen mixing behaviour in a typical CANDU reactor containment following a severe reactor accident. Optimal cell sizes were found for different room volumes, hydrogen release profiles and elevations using spatial convergence criteria. The findings of this study provide the technical basis for the cell size selection in the GOTHIC distributed parameter models used for analysing hydrogen mixing behaviour. (author). 1 ref., 1 tab., 13 figs

  16. Chlorophyll, temperature, depth, and irradiance data from bottle in a world-wide distribution from 28 February 1964 to 02 April 1994 (NODC Accession 0000268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chlorophyll, temperature, depth, and irradiance data were collected using bottle from multiple vessels in a world-wide distribution from 28 February 1964 to 02 April...

  17. Depth, chlorophyll, and total pigment data were collected using bottle casts in a world-wide distribution from 16 March 1997 to 30 January 1998 (NODC Accession 0000292)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Depth, chlorophyll, and total pigment data were collected using bottle casts from TIOGA and other platforms in a world-wide distribution from March 16, 1997 to...

  18. Modelling shallow landslide susceptibility by means of a subsurface flow path connectivity index and estimates of soil depth spatial distribution

    Directory of Open Access Journals (Sweden)

    C. Lanni

    2012-11-01

    Full Text Available Topographic index-based hydrological models have gained wide use to describe the hydrological control on the triggering of rainfall-induced shallow landslides at the catchment scale. A common assumption in these models is that a spatially continuous water table occurs simultaneously across the catchment. However, during a rainfall event isolated patches of subsurface saturation form above an impeding layer and their hydrological connectivity is a necessary condition for lateral flow initiation at a point on the hillslope.

    Here, a new hydrological model is presented, which allows us to account for the concept of hydrological connectivity while keeping the simplicity of the topographic index approach. A dynamic topographic index is used to describe the transient lateral flow that is established at a hillslope element when the rainfall amount exceeds a threshold value allowing for (a development of a perched water table above an impeding layer, and (b hydrological connectivity between the hillslope element and its own upslope contributing area. A spatially variable soil depth is the main control of hydrological connectivity in the model. The hydrological model is coupled with the infinite slope stability model and with a scaling model for the rainfall frequency–duration relationship to determine the return period of the critical rainfall needed to cause instability on three catchments located in the Italian Alps, where a survey of soil depth spatial distribution is available. The model is compared with a quasi-dynamic model in which the dynamic nature of the hydrological connectivity is neglected. The results show a better performance of the new model in predicting observed shallow landslides, implying that soil depth spatial variability and connectivity bear a significant control on shallow landsliding.

  19. Electro-catalytic conversion of ethanol in solid electrolyte cells for distributed hydrogen generation

    International Nuclear Information System (INIS)

    Ju, HyungKuk; Giddey, Sarbjit; Badwal, Sukhvinder P.S.; Mulder, Roger J.

    2016-01-01

    Highlights: • Ethanol assisted water electrolysis reduces electric energy input by more than 50%. • Partial oxidation of ethanol leads to formation of undesired chemicals. • Degradation occurs due to formation of by-products and poisoning of catalyst. • Better catalyst has the potential to increase ethanol to H_2 conversion efficiency. • A plausible ethanol electro-oxidation mechanism has been proposed - Abstract: The global interest in hydrogen/fuel cell systems for distributed power generation and transport applications is rapidly increasing. Many automotive companies are now bringing their pre-commercial fuel cell vehicles in the market, which will need extensive hydrogen generation, distribution and storage infrastructure for fueling of these vehicles. Electrolytic water splitting coupled to renewable sources offers clean on-site hydrogen generation option. However, the process is energy intensive requiring electric energy >4.2 kWh for the electrolysis stack and >6 kWh for the complete system per m"3 of hydrogen produced. This paper investigates using ethanol as a renewable fuel to assist with water electrolysis process to substantially reduce the energy input. A zero-gap cell consisting of polymer electrolyte membrane electrolytic cells with Pt/C and PtSn/C as anode catalysts were employed. Current densities up to 200 mA cm"−"2 at 70 °C were achieved at less than 0.75 V corresponding to an energy consumption of about 1.62 kWh m"−"3 compared with >4.2 kWh m"−"3 required for conventional water electrolysis. Thus, this approach for hydrogen generation has the potential to substantially reduce the electric energy input to less than 40% with the remaining energy provided by ethanol. However, due to performance degradation over time, the energy consumption increased and partial oxidation of ethanol led to lower conversion efficiency. A plausible ethanol electro-oxidation mechanism has been proposed based on the Faradaic conversion of ethanol and

  20. In situ analysis of elemental depth distributions in thin films by combined evaluation of synchrotron x-ray fluorescence and diffraction

    International Nuclear Information System (INIS)

    Mainz, R.; Klenk, R.

    2011-01-01

    In this work we present a method for the in situ analysis of elemental depth distributions in thin films using a combined evaluation of synchrotron x-ray fluorescence and energy-dispersive x-ray diffraction signals. We recorded diffraction and fluorescence signals simultaneously during the reactive annealing of thin films. By means of the observed diffraction signals, the time evolution of phases in the thin films during the annealing processes can be determined. We utilized this phase information to parameterize the depth distributions of the elements in the films. The time-dependent fluorescence signals were then taken to determine the parameters representing the parameterized depth distributions. For this latter step, we numerically calculated the fluorescence intensities for a given set of depth distributions. These calculations handle polychromatic excitation and arbitrary functions of depth distributions and take into account primary and secondary fluorescence. Influences of lateral non-uniformities of the films, as well as the accuracy limits of the method, are investigated. We apply the introduced method to analyze the evolution of elemental depth distributions and to quantify the kinetic parameters during a synthesis process of CuInS 2 thin films via the reactive annealing of Cu-In precursors in a sulfur atmosphere.

  1. Depth Dose Distribution Study within a Phantom Torso after Irradiation with a Simulated Solar Particle Event at NSRL

    Science.gov (United States)

    Berger, Thomas; Matthiae, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis; Reitz, Guenther

    2010-01-01

    The adequate knowledge of the radiation environment and the doses incurred during a space mission is essential for estimating an astronaut's health risk. The space radiation environment is complex and variable, and exposures inside the spacecraft and the astronaut's body are compounded by the interactions of the primary particles with the atoms of the structural materials and with the body itself Astronauts' radiation exposures are measured by means of personal dosimetry, but there remains substantial uncertainty associated with the computational extrapolation of skin dose to organ dose, which can lead to over- or underestimation of the health risk. Comparisons of models to data showed that the astronaut's Effective dose (E) can be predicted to within about a +10% accuracy using space radiation transport models for galactic cosmic rays (GCR) and trapped radiation behind shielding. However for solar particle event (SPE) with steep energy spectra and for extra-vehicular activities on the surface of the moon where only tissue shielding is present, transport models predict that there are large differences in model assumptions in projecting organ doses. Therefore experimental verification of SPE induced organ doses may be crucial for the design of lunar missions. In the research experiment "Depth dose distribution study within a phantom torso" at the NASA Space Radiation Laboratory (NSRL) at BNL, Brookhaven, USA the large 1972 SPE spectrum was simulated using seven different proton energies from 50 up to 450 MeV. A phantom torso constructed of natural bones and realistic distributions of human tissue equivalent materials, which is comparable to the torso of the MATROSHKA phantom currently on the ISS, was equipped with a comprehensive set of thermoluminescence detectors and human cells. The detectors are applied to assess the depth dose distribution and radiation transport codes (e.g. GEANT4) are used to assess the radiation field and interactions of the radiation field

  2. The P1-approximation for the Distribution of Neutrons from a Pulsed Source in Hydrogen

    International Nuclear Information System (INIS)

    Claesson, A.

    1963-12-01

    The asymptotic distribution of neutrons from a pulsed, high energy source in an infinite moderator has been obtained earlier in a 'diffusion' approximation. In that paper the cross section was assumed to be constant over the whole energy region and the time derivative of the first moment was disregarded. Here, first, an analytic expression is obtained for the density in a P 1 -approximation. However, the result is very complicated, and it is shown that an asymptotic solution can be found in a simpler way. By taking into account the low hydrogen scattering cross section at the source energy it follows that the space dependence of the distribution is less than that obtained earlier. The importance of keeping the time derivative of the first moment is further shown in a perturbation approximation

  3. Simulating pH and hydrogen sulfide in a distributed collection system

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Le Guennec, Anne; Nielsen, Asbjørn Haaning

    2013-01-01

    A concept for modeling the pH in distributed sewer systems is presented. The concept is an extension of the existing sewer process model WATS, which simulates physical, chemical and biological processes in wastewater, biofilms, sediments, and sewer headspace, as well as water flow, gas flow, and ....... The pH decreased from 7.80 of fresh wastewater entering the nodes to 7.30 at the treatment plant. This decrease could be attributed to the processes of anaerobic fermentation and hydrogen sulfide formation in the network.......A concept for modeling the pH in distributed sewer systems is presented. The concept is an extension of the existing sewer process model WATS, which simulates physical, chemical and biological processes in wastewater, biofilms, sediments, and sewer headspace, as well as water flow, gas flow...

  4. Analysis of hydrogen distribution on Mg-Ni alloy surface by scanning electron-stimulated desorption ion microscope (SESDIM)

    International Nuclear Information System (INIS)

    Yamaga, Atsushi; Hibino, Kiyohide; Suzuki, Masanori; Yamada, Masaaki; Tanaka, Kazuhide; Ueda, Kazuyuki

    2008-01-01

    Hydrogen distribution and behavior on a Mg-Ni alloy surface are studied by using a time-of-flight electron-stimulated desorption (TOF-ESD) microscopy and a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). The desorbed hydrogen ions are energy-discriminated and distinguished into two characters in the adsorbed states, which belong to Mg 2 Ni grains and the other to oxygen-contaminated Mg phase at the grain boundaries. Adsorbed hydrogen is found to be stable up to 150 deg. C, but becomes thermally unstable around at 200 deg. C

  5. Effect of unstable layer depth on the pore pressure distribution, case study of the Slano Blato landslide (Slovenia)

    Science.gov (United States)

    Askarinejad, Amin; Secchi, Bandar; Macek, Matej; Petkovsek, Ana; Springman, Sarah

    2013-04-01

    The Slano Blato landslide is one of the largest landslides in Slovenia with a volume of more than 1 mio m3 of moving debris. The landslide is located at the border of Triassic limestone and Eocene flysch formations. Flysch is composed of layers of marls and sandstones. The sliding mass consists mainly of clay and clayey gravel of highly weathered and deteriorated flysch, while a minor part represents grains and blocks of limestones. (Petkovšek et al., 2009). The first documentation of an instability event dates back to 1789 and the landslide was reactivated during a heavy rain period in November 2000. Since then, the ground surface level above the unstable material on the upper zones of the landslide is significantly decreasing so that the current slope surface is now more than 10 m below the terrain surveyed in 1998. The new landslide topography results in different pore pressure distributions in the slope, which were anticipated to have a detrimental effect on the stability and movement regime of the slope. The main goal of this work is to investigate the effect of the overlying debris depth on the pore water pressure distribution during a predefined precipitation scenario. The behaviour of the unsaturated soil and the effects of fissures in the bedrock are also considered in the analysis. Hydro-mechanical simulations were performed using 2D finite element software (PLAXIS) and numerical results are compared with results from analytical models, which use a 1D steady state formulation for the hydraulic part and a 2D limit equilibrium approach to calculate the safety factors. The numerical studies show significant change in the pore water pressure distribution in the landslide body with variation of the debris depth. An increase in the debris depth leads to higher suction due to the deeper location of the water table. Higher suction increases landslide stability due to: i) increase of the effective stress and hence the shear strength of the material and ii

  6. Dworshak Dam impacts assessment and fisheries investigation -- Kokanee depth distribution in Dworshak Reservoir and implications toward minimizing entrainment. Annual progress report, January--December 1994

    International Nuclear Information System (INIS)

    Maiolie, M.A.; Elam, S.

    1996-10-01

    The authors measured the day and night depth distribution of kokanee Oncorhynchus nerka kennerlyi directly upstream of Dworshak Dam from October 1993 to December 1994 using split-beam hydroacoustics. At night most kokanee (70%) were distributed in a diffuse layer about 10 m thick. The depth of the layer varied with the season and ranged from 30 to 40 m deep during winter and from 15 to 25 m deep during summer. Nighttime depth of the kokanee layer during summer roughly corresponded to a zone where water temperatures ranged from 7 C to 12 C. Daytime kokanee distribution was much different with kokanee located in dense schools. Most kokanee (70%) were found in a 5--15 m thick layer during summer. Daytime depth distribution was also shallowest during fall and deepest during winter. Dworshak Dam has structures which can be used for selective water withdrawal and can function in depth ranges that will avoid the kokanee layer. Temperature constraints limit the use of selective withdrawal during the spring, summer, and fall, but in the winter, water is nearly isothermal and the full range of selector gate depths may be utilized. From October 1993 to February 1994, selector gates were positioned to withdraw water from above the kokanee layer. The discharge pattern also changed with more water being released during May and July, and less water being released during fall and winter. A combination of these two changes is thought to have increased kokanee densities to a record high of 69 adults/ha

  7. Measurement of relative depth-dose distribution in radiochromic film dosimeters irradiated with 43-70 keV electron beam for industrial application

    Science.gov (United States)

    Matsui, Shinjiro; Hattori, Takeaki; Nonaka, Takashi; Watanabe, Yuki; Morita, Ippei; Kondo, Junichi; Ishikawa, Masayoshi; Mori, Yoshitaka

    2018-05-01

    The relative dose in a layer, which is thinner than the thickness of the dosimeter is evaluated using simulated depth-dose distributions, and the measured responses of dosimeters with acceleration voltages from 43 to 70 kV, via ultra-low-energy electron beam (ULEB) irradiation. By stacking thin film dosimeters, we confirmed that the simulated depth-dose distributions coincided with the measured depth-dose curve within the measurement uncertainty (k = 2). Using the measurement dose of the 47 μm dosimeter and the simulated depth-dose distribution, the dose of 11 μm dosimeters in the surface was evaluated within the measurement uncertainty (k = 2). We also verified the effectiveness of this method for a thinner layer by changing the acceleration voltage of the irradiation source. We evaluated the relative dose for an adjusted depth of energy deposition from 4.4 μm to 22.8 μm. As a result, this method was found to be effective for a thickness, which is less than the thickness of the dosimeter. When irradiation conditions are well known with accuracy, using the confirmed relative depth-dose distributions across any dosimeter thickness range, a dose evaluation, in several μm steps will possibly improve the design of industrial ULEB processes.

  8. FLUENT calculations of the hydrogen distribution in a containment during the OECD-NEA THAI HM-2 experiment

    International Nuclear Information System (INIS)

    Visser, D.C.; Komen, E.M.J.; Houkema, M.; Siccama, N.B.; Kyttaelae, Juha; Huhtanen, Risto; Takasuo, Eveliina

    2009-01-01

    Hydrogen may be released into the containment atmosphere of a nuclear power plant during a severe accident. Locally, high hydrogen concentrations may be reached that can possibly cause fast deflagration or even detonation and put the integrity of the containment at risk. Therefore, the distribution and mixing of hydrogen is an important safety issue for nuclear power plants. Computer codes can be applied to predict the hydrogen distribution in the containment within the course of a hypothetical severe accident and get an estimate of the local hydrogen concentration in the various zones of the containment. In this way the risk associated with the hydrogen safety issue can be determined, and safety related measurements and procedures could be assessed. In order to validate the existing computer codes in the context of hydrogen distribution in the containment of a nuclear power plant, experimental benchmark studies have been performed in the German Thermal-hydraulics, Hydrogen, Aerosols and Iodine (THAI) facility in the framework of the OECD-NEA THAI project. In order to demonstrate the capabilities of the commercial Computational Fluid Dynamics (CFD) code FLUENT the THAI HM-2 test was simulated independently by NRG and VTT. In the first phase of the HM-2 test a stratified hydrogen rich light gas layer was established in the upper part of the THAI containment. In the second phase steam was injected at a lower position inducing a rising plume that gradually dissolved the stratified hydrogen-rich layer from below. Thermo-dynamic phenomena like natural convection, mixing, condensation, heat transfer and distribution in different zones that are expected in severe accidents are involved. The calculated results by NRG and VTT (on hydrogen concentration, temperature, pressure and flow velocity) are compared to the experimental results. The most important differences between the CFD model of NRG and VTT are the computational mesh, condensation model and treatment of the solid

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

    Science.gov (United States)

    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.

  10. Distribution of Mast Cells and Locations, Depths, and Sizes of the Putative Acupoints CV 8 and KI 16

    Directory of Open Access Journals (Sweden)

    Sharon Jiyoon Jung

    2017-01-01

    Full Text Available The anatomical locations and sizes of acupuncture points (APs are identified in traditional Chinese medicine by using the cun measurement method. More precise knowledge of those locations and sizes to submillimeter precision, along with their cytological characterizations, would provide significant contributions both to scientific investigations and to precise control of the practice of acupuncture. Over recent decades, researchers have come to realize that APs in the skin of rats and humans have more mast cells (MCs than neighboring nonacupoints. In this work, the distribution of MCs in the ventral skin of mice was studied so that it could be used to infer the locations, depths from the epidermis, and sizes of three putative APs. The umbilicus was taken as the reference point, and a transversal cross section through it was studied. The harvested skins from 8-week-old mice were stained with toluidine blue, and the MCs were recognized by their red-purple stains and their metachromatic granules. The three putative APs, CV 8 and the left and the right KI 16 APs, were identified based on their high densities of MCs. These findings also imply that acupuncture may stimulate, through MCs, an immune response to allergic inflammation.

  11. Implementation and validation of the condensation model for containment hydrogen distribution studies

    International Nuclear Information System (INIS)

    Ravva, Srinivasa Rao; Iyer, Kannan N.; Gupta, S.K.; Gaikwad, Avinash J.

    2014-01-01

    Highlights: • A condensation model based on diffusion was implemented in FLUENT. • Validation of a condensation model for the H 2 distribution studies was performed. • Multi-component diffusion is used in the present work. • Appropriate grid and turbulence model were identified. - Abstract: This paper aims at the implementation details of a condensation model in the CFD code FLUENT and its validation so that it can be used in performing the containment hydrogen distribution studies. In such studies, computational fluid dynamics simulations are necessary for obtaining accurate predictions. While steam condensation plays an important role, commercial CFD codes such as FLUENT do not have an in-built condensation model. Therefore, a condensation model was developed and implemented in the FLUENT code through user defined functions (UDFs) for the sink terms in the mass, momentum, energy and species balance equations together with associated turbulence quantities viz., kinetic energy and dissipation rate. The implemented model was validated against the ISP-47 test of TOSQAN facility using the standard wall functions and enhanced wall treatment approaches. The best suitable grid size and the turbulence model for the low density gas (He) distribution studies are brought out in this paper

  12. A comparative economic assessment of hydrogen production from large central versus smaller distributed plant in a carbon constrained world

    International Nuclear Information System (INIS)

    Nguyen, Y.V.; Ngo, Y.A.; Tinkler, M.J.; Cowan, N.

    2003-01-01

    This paper compares the economics of producing hydrogen at large central plants versus smaller distributed plants at user sites. The economics of two types of central plant, each at 100 million standard cubic feet per day of hydrogen, based on electrolysis and natural gas steam reforming technologies, will be discussed. The additional cost of controlling CO 2 emissions from the natural gas steam reforming plant will be included in the analysis in order to satisfy the need to live in a future carbon constrained world. The cost of delivery of hydrogen from the large central plant to the user sites in a large metropolitan area will be highlighted, and the delivered cost will be compared to the cost from on-site distributed generation plants. Five types of distributed generation plants, based on proton exchange membrane, alkaline electrolysis and advanced steam reforming, will be analysed and discussed. Two criteria were used to rank various hydrogen production options, the cost of production and the price of hydrogen to achieve an acceptable return of investment. (author)

  13. Monte Carlo simulation of the electron and X-ray depth distribution for quantitative electron probe microanalysis of PWR spent fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyoung Mun; Lee, Hyung Kwon; Son, Young Zoon; Chun, Yong Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Electron probe microanalysis requires several corrections to quantify an element of a specimen. The X-rays produced by the primary beam are created at some depth in the specimen. This distribution is usually represented as the function {Phi}(pz), and it is possible to calculate the correction factors for atomic number and absorption effects. The electron and X-ray depth distributions for a quantitative electron probe micro analysis were simulated by the CASINO Monte Carlo program to quantify some elements of the PWR spent fuel with 50 GWd/tU of burnup and 2 years of cooling time

  14. Monte Carlo simulation of the electron and X-ray depth distribution for quantitative electron probe microanalysis of PWR spent fuels

    International Nuclear Information System (INIS)

    Kwon, Hyoung Mun; Lee, Hyung Kwon; Son, Young Zoon; Chun, Yong Bum

    2011-01-01

    Electron probe microanalysis requires several corrections to quantify an element of a specimen. The X-rays produced by the primary beam are created at some depth in the specimen. This distribution is usually represented as the function Φ(pz), and it is possible to calculate the correction factors for atomic number and absorption effects. The electron and X-ray depth distributions for a quantitative electron probe micro analysis were simulated by the CASINO Monte Carlo program to quantify some elements of the PWR spent fuel with 50 GWd/tU of burnup and 2 years of cooling time

  15. Community Energy: Analysis of Hydrogen Distributed Energy Systems with Photovoltaics for Load Leveling and Vehicle Refueling

    Energy Technology Data Exchange (ETDEWEB)

    Steward, D.; Zuboy, J.

    2014-10-01

    Energy storage could complement PV electricity generation at the community level. Because PV generation is intermittent, strategies must be implemented to integrate it into the electricity system. Hydrogen and fuel cell technologies offer possible PV integration strategies, including the community-level approaches analyzed in this report: (1) using hydrogen production, storage, and reconversion to electricity to level PV generation and grid loads (reconversion scenario); (2) using hydrogen production and storage to capture peak PV generation and refuel hydrogen fuel cell electric vehicles (FCEVs) (hydrogen fueling scenario); and (3) a comparison scenario using a battery system to store electricity for EV nighttime charging (electric charging scenario).

  16. Determination of the thickness distribution of a graphene layer grown on a 2″ SiC wafer by means of Auger electron spectroscopy depth profiling

    International Nuclear Information System (INIS)

    Kotis, L.; Gurban, S.; Pecz, B.; Menyhard, M.; Yakimova, R.

    2014-01-01

    Highlights: • The thickness of graphene grown on SiC was determined by AES depth profiling. • The AES depth profiling verified the presence of buffer layer on SiC. • The presence of unsaturated Si bonds in the buffer layer has been shown. • Using multipoint analysis thickness distribution of the graphene on the wafer was determined. - Abstract: Auger electron spectroscopy (AES) depth profiling was applied for determination of the thickness of a macroscopic size graphene sheet grown on 2 in. 6H-SiC (0 0 0 1) by sublimation epitaxy. The measured depth profile deviated from the expected exponential form showing the presence of an additional, buffer layer. The measured depth profile was compared to the simulated one which allowed the derivation of the thicknesses of the graphene and buffer layers and the Si concentration of buffer layer. It has been shown that the graphene-like buffer layer contains about 30% unsaturated Si. The depth profiling was carried out in several points (diameter 50 μm), which permitted the constructing of a thickness distribution characterizing the uniformity of the graphene sheet

  17. Statistical distribution of hydrogen over three positions in the brucite Mg(OH)2 structure from electron diffractometry data

    International Nuclear Information System (INIS)

    Zhukhlistov, A.A.; Avilov, A.S.; Ferraris, D.; Zvyagin, B.B.; Plotnikov, V.P.

    1997-01-01

    The method of improved automatic electron diffractometry for measuring and recording intensities to two-dimensionally distributed reflections of texture-type electron diffraction patterns has been used for the analysis of the brucite Mg(OH) 2 structure. The experimental accuracy of the measured intensities proved to be sufficient for studying fine structural details of the statistical distribution of hydrogen atoms over three structure positions located around the threefold axis of the brucite structure

  18. Development of a multi-layer ion chamber for measurement of depth dose distributions of heavy-ion therapeutic beam for individual patients

    International Nuclear Information System (INIS)

    Shimbo, Munefumi; Futami, Yasuyuki; Yusa, Ken; Matsufuji, Naruhiro; Kanai, Tatsuaki; Urakabe, Eriko; Yamashita, Haruo; Akagi, Takashi; Higashi, Akio

    2000-01-01

    In heavy-ion radiotherapy, an accelerated beam is modified to realize a desired dose distribution in patients. The set-up of the beam-modifying devices in the irradiation system is changed according to the patient, and it is important to check the depth dose distributions in the patient. In order to measure dose distributions realized by an irradiation system for heavy-ion radiotherapy, a multi-layer ionization chamber (MLIC) was developed. The MLIC consists of 64 ionization chambers, which are stacked mutually. The interval between each ionization chamber is about 4.1 mm water. There are signal and high voltage plates in the MLIC, which are used as electrodes of the ionization chambers and phantom. Depth dose distribution from 5.09 mm to 261.92 mm water can be measured in about 30 seconds using this MLIC. Thus, it is possible to check beam quality in a short amount of time. (author)

  19. Depth Distribution Studies of Carbon in Steel Surfaces by Means of Charged Particle Activation Analysis with an Account of Heat and Diffusion Effects in the Sample

    International Nuclear Information System (INIS)

    Brune, D.; Lorenzen, J.; Witalis, E.

    1972-05-01

    Depth distribution studies of carbon in steel and iron were carried out in the concentration range 0.05-1 %, using proton activation analysis. Surface content studies were performed in the concentration range 0.01-1 % using deuteron activation analysis. The following reactions were utilized: 12 C(p,γ) 13 N and 12 C(d,n) 13 N Evaluations of depth distribution were based on resonances in the excitation function. The carbon content was determined with the aid of the positron emitter, 13 N, using either single-peak or coincidence measurements. The heat dissipation in the irradiated region of the samples was calculated, and the temperature rise was measured using thermocouples. The temperature distribution within the hot zone subjected to irradiation by charged particles, together with the temperature distribution around this zone, was studied in order to estimate any effect this might have on the carbon diffusion. A device for automatic sample exchange which is remotely controlled is described

  20. Distribution of deuterium and hydrogen in Zr and Ti foil assemblies under the action of a pulsed deuterium high-temperature plasma

    Science.gov (United States)

    Bondarenko, G. G.; Volobuev, I. V.; Eriskin, A. A.; Kobzev, A. P.; Nikulin, V. Ya.; Peregudova, E. N.; Silin, P. V.; Borovitskaya, I. V.

    2017-09-01

    Deuteron and proton elastic recoil detection analysis is used to study the accumulation and redistribution of deuterium and hydrogen in assemblies of two high-pure zirconium or titanium foils upon pulsed action of high-temperature deuterium plasma (PHTDP) in a plasma-focus installation PF-4. It is noted that, under the action of PHTDP, an implanted deuterium and hydrogen gas impurity are redistributed in the irradiated foils in large depths, which are significantly larger than the deuterium ion free paths (at their maximum velocity to 108 cm/s). The observed phenomenon is attributed to the carrying out of implanted deuterium and hydrogen under the action of powerful shock waves formed in the metallic foils under the action of PHTDP and/or the acceleration of diffusion of deuterium and hydrogen atoms under the action of a compression-rarefaction shock wave at the shock wave front with the redistribution of deuterium and hydrogen to large depths.

  1. Spatio-temporal distribution of Diaphanosoma brachyurum (Cladocera: Sididae in freshwater reservoir ecosystems: importance of maximum water depth and macrophyte beds for avoidance of fish predation

    Directory of Open Access Journals (Sweden)

    Jong-Yun Choi

    2014-10-01

    Full Text Available In empirical studies, Cladocera is commonly utilized as a primary food source for predators such as fish, thus, predator avoidance are important strategies to sustain their population in freshwater ecosystems. In this study, we tested the hypothesis that water depth is an important factor in determining the spatial distribution of Diaphanosoma brachyurum Liévin, 1848 in response to fish predation. Quarterly monitoring was implemented at three water layers (i.e., water surface and middle and bottom layers in 21 reservoirs located in the southeastern part of South Korea. D. brachyurum individuals were frequently observed at the study sites and exhibited different spatial patterns of distribution in accordance with the maximum depth of the reservoirs. In the reservoirs with a maximum depth of more than 6 m, high densities of D. brachyurum were observed in the bottom layers; however, in the shallower reservoirs (maximum depth <6 m, D. brachyurum were concentrated in the surface layer. Moreover, during additional surveys, we observed a trend in which D. brachyurum densities increased as the maximum depth or macrophyte biomass increased. Gut contents analysis revealed that predatory fishes in each reservoir frequently consumed D. brachyurum; however, the consumption rate abruptly decreased in reservoirs where the maximum depth was more than 11 m or in the shallow reservoirs supporting a macrophyte bed. Interestingly, the reservoirs more than 11-m depth supported high densities of D. brachyurum in the bottom layer and in the surface macrophyte bed. Based on these results, reservoirs with a maximum depth of more than 11 m or those with a macrophyte bed may provide a refuge for D. brachyurum to avoid fish predation. Compared with other cladoceran species, D. brachyurum readily exploits various types of refugia (in this study, the deep layer or surface macrophyte bed, which may help explain why this species is abundant in various types of reservoirs.

  2. Integrated analysis of transportation demand pathway options for hydrogen production, storage, and distribution

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    Directed Technologies, Inc. has begun the development of a computer model with the goal of providing guidance to the Hydrogen Program Office regarding the most cost effective use of limited resources to meet national energy security and environmental goals through the use of hydrogen as a major energy carrier. The underlying assumption of this programmatic pathway model is that government and industry must work together to bring clean hydrogen energy devices into the marketplace. Industry cannot provide the long term resources necessary to overcome technological, regulatory, institutional, and perceptual barriers to the use of hydrogen as an energy carrier, and government cannot provide the substantial investments required to develop hydrogen energy products and increased hydrogen production capacity. The computer model recognizes this necessary government/industry partnership by determining the early investments required by government to bring hydrogen energy end uses within the time horizon and profitability criteria of industry, and by estimating the subsequent investments required by industry. The model then predicts the cost/benefit ratio for government, based on contributions of each hydrogen project to meeting societal goals, and it predicts the return on investment for industry. Sensitivity analyses with respect to various government investments such as hydrogen research and development and demonstration projects will then provide guidance as to the most cost effective mix of government actions. The initial model considers the hydrogen transportation market, but this programmatic pathway methodology will be extended to other market segments in the future.

  3. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions

    Energy Technology Data Exchange (ETDEWEB)

    Ingerle, D., E-mail: dingerle@ati.ac.at [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Vienna (Austria); Meirer, F. [Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (Netherlands); Pepponi, G.; Demenev, E.; Giubertoni, D. [MiNALab, CMM-irst, Fondazione Bruno Kessler, Via Sommarive 18, I-38050 Povo (Italy); Wobrauschek, P.; Streli, C. [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Vienna (Austria)

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  4. Analysis of Hydrogen Concentration Distribution during an SBO Accident for Shin-Ulchin APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongtae; Hong, Seong Wan [Korea Atomic energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    To prohibit the accumulation of hydrogen, the containment volume is considered to reduce the hydrogen concentration, or hydrogen mitigation devices such as PARs or igniters are installed in the containment. In the case of the Fukushima NPPs, the applied strategy for the hydrogen safety is the use of a containment venting system (CVS). In this way, the hydrogen accumulated in the containment vessel is vented into the environment. One of the causes of the hydrogen explosions occurring in the containment buildings of the Fukushima NPPs is expected to be the failure of the venting system. The hydrogen was therefore easily accumulated in the containment building. It is uncertain what the ignition source for the hydrogen combustion was during the accident. However, it is not too conservative to assume that an ignition source exists at any time and any place in a containment during a core-melt accident. Shin-Ulchin 1 and 2, which are construction plants of an APR 1400, are two of the newest NPPs in Korea. They have many features to enhance the safety margin during a design-based and beyond-design-based accident. One of them is the in-containment refueling water storage tank (IRWST) located inside the containment. It is used as a sink/source for feed-bleed operation. When the core is damaged along an accident progression, the hydrogen generated in the RPV can be released into the IRWST of the APR1400 with steam and water. From a previous study, it was found that a highly concentrated hydrogen/air mixture can be developed if the hydrogen is released into the IRWST. In the case of Shin-Ulchin 1 and 2, the hydrogen mitigation strategy during a high-pressure accident such as a station blackout (SBO) is changed by installing a 3-way valve. When a severe accident management (SAM) for the plant is initiated, the flow path from a pressurizer to the IRWST is changed into a steam-generator (S/G) compartment by turning the 3-wat valve actively (pilot operated). By doing so, it is

  5. First evaluation of experimental results describing pressure buildup and hydrogen distribution, obtained by experimental series E11

    International Nuclear Information System (INIS)

    Holzbauer, H.; Wolf, L.; Valencia, L.

    1990-01-01

    The beginning of the core meltdown process in the reactor pressure vessel, with a supposed release position for hydrogen in the upper part of the containment, is simulated, and the influence of the plant geometry on the distribution process is studied. In addition, the release point is shifted to the lower containment area, additional hydrogen production owing to the interaction between concrete and melt is taken into account, and sump boiling is simulated. The experimental program covers analytical investigations in the form of blind post-calculations. (DG) [de

  6. Westinghouse-GOTHIC modeling of NUPEC's hydrogen mixing and distribution test M-4-3

    International Nuclear Information System (INIS)

    Ofstun, R.P.; Woodcock, J.; Paulsen, D.L.

    1994-01-01

    NUPEC (NUclear Power Engineering Corporation) ran a series of hydrogen mixing and distribution tests which were completed in April 1992. These tests were performed in a 1/4 linearly scaled model containment and were specifically designed to be used for computer code validation. The results of test M-4-3, along with predictions from several computer codes, were presented to the participants of ISP-35 (a blind test comparison of code calculated results with data from NUPEC test M-7-1) at a meeting in March 1993. Test M-4-3, which was similar to test M-7-1, released a mixture of steam and helium into a steam generator compartment located on the lower level of containment. The majority of codes did well at predicting the global pressure and temperature trends, however, some typical lumped parameter modeling problems were identified at that time. In particular, the models had difficulty predicting the temperature and helium concentrations in the so called 'dead ended volumes' (pressurizer compartment and in-core chase region). Modeling of the dead-ended compartments using a single lumped parameter volume did not yield the appropriate temperature and helium response within that volume. The Westinghouse-GOTHIC (WGOTHIC) computer code is capable of modeling in one, two or three dimensions (or any combination thereof). This paper describes the WGOTHIC modeling of the dead-ended compartments for NUPEC test M-4-3 and gives comparisons to the test data. 1 ref., 1 tab., 14 figs

  7. Distribution of 137Cs in benthic plants along depth profiles in the outer Puck Bay (Baltic Sea)

    International Nuclear Information System (INIS)

    Tamara Zalewska

    2012-01-01

    A study was conducted on three macroalgae species: Polysiphonia fucoides and Furcellaria lumbricalis, the species of the red algae division, and Cladophora glomerata, representing the green algae division, as well as Zostera marina, representing vascular plants. The main aim of the study was to recognize the level of 137 Cs concentrations in the plants, which could be used as a measurement of bioaccumulation efficiency in the selected macrophytes at varying depths, and in the seasonal resolution of the vegetation period: spring-summer and autumnal. The plants' biomass clearly showed seasonal variability, as did the 137 Cs concentrations in the plants. Cesium activity also changed with depth. Seasonal variability in radionuclide content in the plants, as well as the differences in its activity determined along the depth profile, were related mainly to the plant biomass and the dilution effect caused by the biomass increment and reflected the growth dynamics. P. fucoides showed much greater bioaccumulation ability at each depth as compared to C. glomerata, a green algae. Lower concentrations of 137 Cs were also identified in F. lumbricalis and in Z. marina, mostly as a result of differences in morphology and physiology. P. fucoides can be recommended as a bioindicator for the monitoring of 137 Cs contamination due to the high efficiency of bioaccumulation and the available biomass along the depth profile, as well as the occurrence throughout the entire vegetation season. (author)

  8. Effect of tool plunge depth on reinforcement particles distribution in surface composite fabrication via friction stir processing

    Directory of Open Access Journals (Sweden)

    Sandeep Rathee

    2017-04-01

    Full Text Available Aluminium matrix surface composites are gaining alluring role especially in aerospace, defence, and marine industries. Friction stir processing (FSP is a promising novel solid state technique for surface composites fabrication. In this study, AA6061/SiC surface composites were fabricated and the effect of tool plunge depth on pattern of reinforcement particles dispersion in metal matrix was investigated. Six varying tool plunge depths were chosen at constant levels of shoulder diameter and tool tilt angle to observe the exclusive effect of plunge variation. Process parameters chosen for the experimentation are speed of rotation, travel speed and tool tilt angle which were taken as 1400 rpm, 40 mm/min, and 2.5°respectively. Macro and the microstructural study were performed using stereo zoom and optical microscope respectively. Results reflected that lower plunge depth levels lead to insufficient heat generation and cavity formation towards the stir zone center. On the other hand, higher levels of plunge depth result in ejection of reinforcement particles and even sticking of material to tool shoulder. Thus, an optimal plunge depth is needed in developing defect free surface composites.

  9. The orientation dependence of the hydrogen distribution within Mo/V (110) and (001) multilayered artificial superlattices

    CERN Document Server

    Hjörvarsson, B; Olafsson, S; Karlsson, E B; Birch, J; Sundgren, J E

    1997-01-01

    We have investigated the hydrogen distribution within multilayered Mo/V (110) and (001) artificial superlattices. The hydrogen concentration, determined by the sup 1 H( sup 1 sup 5 N, alpha gamma) sup 1 sup 2 C nuclear resonance reaction, is found to decrease with decreasing layer thickness. The decrease is attributed to an interface region with reduced hydrogen content. The extension of this interface region is found to be two monolayers in Mo/V (110), compared to the previously reported three monolayers in Mo/V (001) superlattices. In the (110) oriented samples the relative amount of H in the interface region decreases with increasing average H content (H/V (atomicratio) approx. 0.3-0.5). This effect is shown to be related to the orientation of the hydrogen planes with respect to the boundaries implied by the Mo/V interfaces. The hydrogen induced volume change, obtained by conventional theta-2 theta x-ray diffraction (XRD) and reciprocal space mapping, is found to be smaller for the (110) samples than for t...

  10. Development of hydrogen market: the outlook for demand, wing energy production, mass storage and distribution to vehicles in the regions

    International Nuclear Information System (INIS)

    Le Duigou, A.; Quemere, M.M.; Marion, P.; Decarre, S.; Sinegre, L.; Nadau, L.; Pierre, H.; Menanteau, Ph.; Rastetter, A.; Cuni, A.; Barbier, F.; Mulard, Ph.; Alleau, Th.; Antoine, L.

    2011-01-01

    The HyFrance3 project has provided a national framework for reflection, debate and strategic exchange between major public and industrial research players, namely for their hydrogen technology arms in France (Air Liquide, Total Refining and Marketing, EDF R and D, GDF SUEZ, CNRS-LEPII Energies Nouvelles, AFH2, ALPHEA, ADEME (co-financing and partner) and the CEA (coordinator). This project focuses on studying the landscape, trends and economic competitiveness of some links in the hydrogen chain, for industrial and energy applications, over a period referred to as 'short term' (2020-2030). Four study subjects were tackled: the prospective demand for hydrogen in industry (analysis of the current situation and outlook for 2030, in particular for refining based on two scenarios on mobility), production of hydrogen for transport uses from wind-produced electricity, mass storage that would have to be set up in the Rhone Alpes and PACA regions, to balance supply that is subject to deliberate (maintenance) or involuntary interruptions, and the distribution of hydrogen in the region, for automobile use (gas station network in the Rhone Alpes and PACA regions) by 2050 (with end period all-in costs between 0.4 eur/kg and 0.6 eur/kg, as a function of the price of energy and the distance from the storage site). (authors)

  11. Hydrogen isotope distributions and retentions in the inner divertor tile of JT-60U

    Energy Technology Data Exchange (ETDEWEB)

    Oya, Y. [Radioisotope Center, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan)]. E-mail: yoya@ric.u-tokyo.ac.jp; Hirohata, Y. [Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Tanabe, T. [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Shibahara, T. [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Kimura, H. [Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Oyaidzu, M. [Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Arai, T. [Naka Fusion Establishment, Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan); Masaki, K. [Naka Fusion Establishment, Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan); Gotoh, Y. [Naka Fusion Establishment, Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan); Okuno, K. [Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Miya, N. [Naka Fusion Establishment, Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan); Hino, T. [Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Tanaka, S. [Graduate School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan)

    2005-11-15

    Retention profiles of hydrogen and deuterium in graphite tiles placed in the inner divertor region of JT-60U were analyzed by secondary ion mass spectroscopy (SIMS) and thermal desorption spectroscopy (TDS). The difference in hydrogen and deuterium retention behaviour is discussed considering the frequency of the strike-point hit and history of NBI heating power. It was found that most of hydrogen/deuterium was retained in the deposited layers, HH deposition layers/DD deposition layers or co-deposited with carbon. Owing to the higher heating power of DD discharges, the deuterium concentration in the DD deposition layers was much lower than that of hydrogen in the HH deposition layers. On the area showing no deposition, very shallow profile of deuterium dominated hydrogen profile. These results indicate that the tritium retention is strongly influenced by the history of discharge and temperatures. Tritium retention on graphite tiles and deposition layers could be significantly reduced with increasing the operation temperature.

  12. Hydrogen isotope distributions and retentions in the inner divertor tile of JT-60U

    International Nuclear Information System (INIS)

    Oya, Y.; Hirohata, Y.; Tanabe, T.; Shibahara, T.; Kimura, H.; Oyaidzu, M.; Arai, T.; Masaki, K.; Gotoh, Y.; Okuno, K.; Miya, N.; Hino, T.; Tanaka, S.

    2005-01-01

    Retention profiles of hydrogen and deuterium in graphite tiles placed in the inner divertor region of JT-60U were analyzed by secondary ion mass spectroscopy (SIMS) and thermal desorption spectroscopy (TDS). The difference in hydrogen and deuterium retention behaviour is discussed considering the frequency of the strike-point hit and history of NBI heating power. It was found that most of hydrogen/deuterium was retained in the deposited layers, HH deposition layers/DD deposition layers or co-deposited with carbon. Owing to the higher heating power of DD discharges, the deuterium concentration in the DD deposition layers was much lower than that of hydrogen in the HH deposition layers. On the area showing no deposition, very shallow profile of deuterium dominated hydrogen profile. These results indicate that the tritium retention is strongly influenced by the history of discharge and temperatures. Tritium retention on graphite tiles and deposition layers could be significantly reduced with increasing the operation temperature

  13. Benchmark on hydrogen distribution in a containment based on the OECD-NEA THAI HM-2 experiment

    International Nuclear Information System (INIS)

    Schwarz, S.; Fischer, K.; Bentaib, A.

    2009-01-01

    Within the course of a hypothetical severe accident in a nuclear power plant, hydrogen can be generated in the primary circuit and released into the containment. Considering the possibility of a deflagration, the simulation of the hydrogen distribution in the containment by computer codes is of major importance. In order to create a data base for code validation, several distribution experiments using helium and hydrogen have been performed in the German THAI (Thermal-Hydraulics, Hydrogen, Aerosols, Iodine) facility. They started with the ISP-47 test TH13 and were followed by the HM (Hydrogen-Helium Material Scaling Tests) series. The objectives of the HM Tests are to confirm the transferability of existing helium distribution test data to hydrogen distribution problems, to understand the processes that lead to the formation and dissolution of a light cloud stratification. The test HM-2 was chosen for a code benchmark. During the first phase of test HM-2 a light gas cloud consisting of hydrogen and nitrogen was established in the upper half of the facility. In the second phase steam was injected at a lower position inducing a rising steam - nitrogen plume. The plume did not break through the cloud, because its density was higher than the density of the cloud. Therefore the cloud was gradually dissolved from its bottom. Eleven organisations performed 'blind' calculations to the HM-2 experiment. The lumped parameter (LP) codes ASTEC, COCOSYS and MELCOR and the CFD codes FLUENT, GASFLOW and GOTHIC were used. The main phenomena were natural convection, interaction between the rising plume and the light gas cloud, steam condensation on walls, fog behaviour and the heat up of the walls. The experimental data of the first phase had been published and the atmospheric stratification was simulated reasonably well. The data from the second phase stayed concealed until the simulated results were submitted. The thermal-hydraulic phenomena were predicted well by several LP- and

  14. Analytical theory relating the depth of the sulfate-methane transition to gas hydrate distribution and saturation

    Science.gov (United States)

    Bhatnagar, Gaurav; Chatterjee, Sayantan; Chapman, Walter G.; Dugan, Brandon; Dickens, Gerald R.; Hirasaki, George J.

    2011-03-01

    We develop a theory that relates gas hydrate saturation in marine sediments to the depth of the sulfate-methane transition (SMT) zone below the seafloor using steady state, analytical expressions. These expressions are valid for systems in which all methane transported into the gas hydrate stability zone (GHSZ) comes from deeper external sources (i.e., advective systems). This advective constraint causes anaerobic oxidation of methane to be the only sulfate sink, allowing us to link SMT depth to net methane flux. We also develop analytical expressions that define the gas hydrate saturation profile based on SMT depth and site-specific parameters such as sedimentation rate, methane solubility, and porosity. We evaluate our analytical model at four drill sites along the Cascadia Margin where methane sources from depth dominate. With our model, we calculate average gas hydrate saturations across GHSZ and the top occurrence of gas hydrate at these sites as 0.4% and 120 mbsf (Site 889), 1.9% and 70 mbsf (Site U1325), 4.7% and 40 mbsf (Site U1326), and 0% (Site U1329), mbsf being meters below seafloor. These values compare favorably with average saturations and top occurrences computed from resistivity log and chloride data. The analytical expressions thus provide a fast and convenient method to calculate gas hydrate saturation and first-order occurrence at a given geologic setting where vertically upward advection dominates the methane flux.

  15. Depth dose distribution in the water for clinical applicators of 90Sr + 90Y, with a extrapolation mini chamber

    International Nuclear Information System (INIS)

    Antonio, Patricia de Lara; Caldas, Linda V.E.; Oliveira, Mercia L.

    2009-01-01

    This work determines the depth dose in the water for clinical applicators of 90 Sr + 90 Y, using a extrapolation mini chamber developed at the IPEN, Sao Paulo, Brazil, and different thickness acrylic plates. The obtained results were compared with the international recommendations and were considered satisfactory

  16. Stochastic distribution of the required coefficient of friction for level walking--an in-depth study.

    Science.gov (United States)

    Chang, Wen-Ruey; Matz, Simon; Chang, Chien-Chi

    2012-01-01

    This study investigated the stochastic distribution of the required coefficient of friction (RCOF) which is a critical element for estimating slip probability. Fifty participants walked under four walking conditions. The results of the Kolmogorov-Smirnov two-sample test indicate that 76% of the RCOF data showed a difference in distribution between both feet for the same participant under each walking condition; the data from both feet were kept separate. The results of the Kolmogorov-Smirnov goodness-of-fit test indicate that most of the distribution of the RCOF appears to have a good match with the normal (85.5%), log-normal (84.5%) and Weibull distributions (81.5%). However, approximately 7.75% of the cases did not have a match with any of these distributions. It is reasonable to use the normal distribution for representation of the RCOF distribution due to its simplicity and familiarity, but each foot had a different distribution from the other foot in 76% of cases. The stochastic distribution of the required coefficient of friction (RCOF) was investigated for use in a statistical model to improve the estimate of slip probability in risk assessment. The results indicate that 85.5% of the distribution of the RCOF appears to have a good match with the normal distribution.

  17. Analysis of mitigating measures during steam/hydrogen distributions in nuclear reactor containments with the 3D field code gasflow

    International Nuclear Information System (INIS)

    Royl, P.; Travis, J.R.; Haytcher, E.A.; Wilkening, H.

    1997-01-01

    This paper reports on the recent model additions to the 3D field code GASFLOW and on validation and application analyses for steam/hydrogen transport with inclusion of mitigation measures. The results of the 3D field simulation of the HDR test E11.2 are summarized. Results from scoping analyses that simulate different modes of CO2 inertization for conditions from the HDR test T31.5 are presented. The last part discusses different ways of recombiner modeling during 3D distribution simulations and gives the results from validation calculations for the HDR recombiner test E11.8.1 and the Battelle test MC3. The results demonstrate that field code simulations with computer codes like GASFLOW are feasible today for complex containment geometries and that they are necessary for a reliable prediction of hydrogen/steam distribution and mitigation effects. (author)

  18. The hydrogen atom-deuterium molecule reaction: Experimental determination of product quantum state distributions

    International Nuclear Information System (INIS)

    Rinnen, K.

    1989-01-01

    The H + H 2 atom exchange reaction (and its isotopic analogs) is the simplest neutral bimolecular chemical reaction because of the small number of electrons in the system and the lightness of the nuclei. The H 3 potential energy surface (PES) is the most accurately known reactive surface (LSTH surface); there have been both quasiclassical trajectory (QCT) and quantal calculations performed on it. This is one of the few systems for which theory is ahead of experiment, and many theoretical predictions await experimental comparison. The H + D 2 → HD + D reaction is studied using thermal D 2 (∼298 K) and translationally hot hydrogen atoms. Photolysis of HI at 266 nm generates H atoms with center-of-mass collision energies of 1.3 and 0.55 eV, both of which are above the classical reaction barrier of 0.42 eV. The rovibrational population distribution of the molecular product is measured by (2+1) resonance-enhanced multiphoton ionization (REMPI). A major effort has been directed toward calibrating the (2+1) REMPI detection procedure, to determine quantitatively the relationship between ion signals and relative quantum state populations for HD. An effusive, high-temperature nozzle has been constructed to populate thermally the high rovibrational levels observed in the reaction. The results are compared to theoretical calculations of the E,F 1 Σ g + - X 1 Σ g + two-photon transition moments. For the H + D 2 reaction, the populations of all energetically accessible HD product levels are measured. Specifically, the following levels are observed: HD(v = 0, J = 0-15), HD(v = 1, J = 0-12), and HD(v = 2, J = 0-8). Of the available energy, 73% is partitioned into product translation, 18% into HD rotation, and 9% into HD vibration

  19. Impact of water depth on the distribution of iGDGTs in the surface sediments from the northern South China Sea: applicability of TEX86 in marginal seas

    Science.gov (United States)

    Chen, Jiali; Hu, Pengju; Li, Xing; Yang, Yang; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning; Lü, Xiaoxia

    2018-03-01

    The TEX 86 H paleothermometer on the base of isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs) has been widely applied to various marine settings to reconstruct past sea surface temperatures (SSTs). However, it remains uncertain how well this proxy reconstructs SSTs in marginal seas. In this study, we analyze the environmental factors governing distribution of iGDGTs in surface sediments to assess the applicability of TEX 86 H paleothermometer in the South China Sea (SCS). Individual iGDGT concentrations increase gradually eastwards. Redundancy analysis based on the relative abundance of an individual iGDGT compound and environmental parameters suggests that water depth is the most influential factor to the distribution of iGDGTs, because thaumarchaeota communities are water-depth dependent. Interestingly, the SST difference (Δ T) between TEX 86 H derived temperature and remote-sensing SST is less than 1°C in sediments with water depth>200 m, indicating that TEX 86 H was the robust proxy to trace the paleo-SST in the region if water depth is greater than 200 m.

  20. Depth to the bottom of magnetic sources (DBMS) from aeromagnetic data of Central India using modified centroid method for fractal distribution of sources

    Science.gov (United States)

    Bansal, A. R.; Anand, S. P.; Rajaram, Mita; Rao, V. K.; Dimri, V. P.

    2013-09-01

    The depth to the bottom of the magnetic sources (DBMS) has been estimated from the aeromagnetic data of Central India. The conventional centroid method of DBMS estimation assumes random uniform uncorrelated distribution of sources and to overcome this limitation a modified centroid method based on scaling distribution has been proposed. Shallower values of the DBMS are found for the south western region. The DBMS values are found as low as 22 km in the south west Deccan trap covered regions and as deep as 43 km in the Chhattisgarh Basin. In most of the places DBMS are much shallower than the Moho depth, earlier found from the seismic study and may be representing the thermal/compositional/petrological boundaries. The large variation in the DBMS indicates the complex nature of the Indian crust.

  1. Depth distribution of secondary phases in kesterite Cu2ZnSnS4 by angle-resolved X-ray absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    J. Just

    2017-12-01

    Full Text Available The depth distribution of secondary phases in the solar cell absorber material Cu2ZnSnS4 (CZTS is quantitatively investigated using X-ray Absorption Near Edge Structure (XANES analysis at the K-edge of sulfur at varying incidence angles. Varying information depths from several nanometers up to the full thickness is achieved. A quantitative profile of the phase distribution is obtained by a self-consistent fit of a multilayer model to the XANES spectra for different angles. Single step co-evaporated CZTS thin-films are found to exhibit zinc and copper sulfide secondary phases preferentially at the front or back interfaces of the film.

  2. Origin and spatial distribution of gas at seismogenic depths of the San Andreas Fault from drill-mud gas analysis

    International Nuclear Information System (INIS)

    Wiersberg, Thomas; Erzinger, Joerg

    2008-01-01

    Data are presented on the molecular composition of drill-mud gas from the lower sedimentary section (1800-3987 m) of the SAFOD (San Andreas Fault Observatory at Depth) Main Hole measured on-line during drilling, as well as C and H isotope data from off-line mud gas samples. Hydrocarbons, H 2 and CO 2 are the most abundant non-atmospheric gases in drill-mud when drilling seismogenic zones. Gas influx into the well at depth is related to the lithology and permeability of the drilled strata: larger formation gas influx was detected when drilling through organic-rich shales and permeable sandstones. The SAF (San Andreas Fault), encountered between approximately 3100 m and 3450 m borehole depth, is generally low in gas, but is encompassed by two gas-rich zones (2700-2900 m and below 3550 m) at the fault margins with enhanced 222 Rn activities and distinct gas compositions. Within the fault, two interstratified gas-rich lenses (3150-3200 m and 3310-3340 m) consist of CO 2 and hydrocarbons (upper zone), but almost exclusively of hydrocarbons (lower zone). The isotopic composition indicates an organic source of hydrocarbons and CO 2 in the entire sedimentary section of the well. Hydrocarbons in sedimentary strata are partly of microbial origin down to ∼2500 m borehole depth. The contribution of thermogenic gas increases between ∼2500 m and 3200 m. Below ∼3200 m, hydrocarbons fully derive from thermal degradation of organic matter. The lack of H 2 in the center of the fault and the high concentration of H 2 in the fractured zones at the fault margins are consistent with H 2 formation by interaction of water with fresh silica mineral surfaces generated by tectonic activities, however, this needs to be verified by laboratory experiments. Based on these studies, it is concluded that the fault zone margins consist of strata with enhanced permeability, separated by a low-permeability fault center

  3. Using high-resolution satellite aerosol optical depth to estimate daily PM2.5 geographical distribution in Mexico City

    OpenAIRE

    Just, Allan C.; Wright, Robert O.; Schwartz, Joel; Coull, Brent A.; Baccarelli, Andrea A.; Tellez-Rojo, Martha María; Moody, Emily; Wang, Yujie; Lyapustin, Alexei; Kloog, Itai

    2015-01-01

    Recent advances in estimating fine particle (PM2.5) ambient concentrations use daily satellite measurements of aerosol optical depth (AOD) for spatially and temporally resolved exposure estimates. Mexico City is a dense megacity that differs from other previously modeled regions in several ways: it has bright land surfaces, a distinctive climatological cycle, and an elevated semi-enclosed air basin with a unique planetary boundary layer dynamic. We extend our previous satellite methodology to...

  4. Element depth profiles of porous silicon

    International Nuclear Information System (INIS)

    Kobzev, A.P.; Nikonov, O.A.; Kulik, M.; Zuk, J.; Krzyzanowska, H.; Ochalski, T.J.

    1997-01-01

    Element depth profiles of porous silicon were measured on the Van-de-Graaff accelerator in the energy range of 4 He + ions from 2 to 3.2 MeV. Application of complementary RBS, ERD and 16 O(α,α) 16 O nuclear reaction methods permits us to obtain: 1) the exact silicon, oxygen and hydrogen distribution in the samples, 2) the distribution of partial pore concentrations. The oxygen concentration in porous silicon reaches 30%, which allows one to assume the presence of silicon oxide in the pores and to explain the spectrum shift of luminescence into the blue area

  5. Role of the interaction processes in the depth-dose distribution of proton beams in liquid water

    International Nuclear Information System (INIS)

    Garcia-Molina, Rafael; Abril, Isabel; De Vera, Pablo; Kyriakou, Ioanna; Emfietzoglou, Dimitris

    2012-01-01

    We use a simulation code, based on Molecular Dynamics and Monte Carlo, to investigate the depth-dose profile and lateral radial spreading of swift proton beams in liquid water. The stochastic nature of the projectile-target interaction is accounted for in a detailed manner by including in a consistent way fluctuations in both the energy loss due to inelastic collisions and the angular deflection from multiple elastic scattering. Depth-variation of the projectile charge-state as it slows down into the target, due to electron capture and loss processes, is also considered. By selectively switching on/off these stochastic processes in the simulation, we evaluate the contribution of each one of them to the Bragg curve. Our simulations show that the inclusion of the energy-loss straggling sizeably affects the width of the Bragg peak, whose position is mainly determined by the stopping power. The lateral spread of the beam as a function of the depth in the target is also examined.

  6. Distribution of benthic invertebrates at different depths in a shallow reservoir in the KwaZulu-Natal Midlands

    Directory of Open Access Journals (Sweden)

    M.J. Samways

    1996-08-01

    Full Text Available The bottom of a freshwater reservoir in the KwaZulu-Natal Midlands was sampled for macro-invertebrates and macrophytes at depths of 0.5 m, 1 m, 2 m, and 3 m. The water plants Elodea spp. which did not occur much beyond 1 m appeared to be a major deter-minant for the presence of invertebrates. At 2 m and 3 m, when temperature and light decreased greatly, it was replaced by the algae Chara spp. Over 98 of the macroinvertebrate individuals in 21 species and 14 families occurred in water 1 m or less in depth. At 2 m and deeper, there was a rapid decline of species, with only one, a snail, occurring at 3 m. Odonata species occurred only in water 1 m or less in depth. Among the Ephemeroptera, Caenis sp. was abundant at 0.5 m and the most dominant species of all. At 1 m, the most dominant species was Cleon palidulosum of the Baetidae. Both in terms of food for waterfowl and trout, and as a reserve for aquatic macroin vertebrates, the shallow fringe of the reservoir was playing by far the major role compared with the deeper, open water. It is recommended both for biotic conservation and fishing that reservoirs have a shallow rim and constant water levels.

  7. Determination of hydrogen abundance in selected lunar soils

    Science.gov (United States)

    Bustin, Roberta

    1987-01-01

    Hydrogen was implanted in lunar soil through solar wind activity. In order to determine the feasibility of utilizing this solar wind hydrogen, it is necessary to know not only hydrogen abundances in bulk soils from a variety of locations but also the distribution of hydrogen within a given soil. Hydrogen distribution in bulk soils, grain size separates, mineral types, and core samples was investigated. Hydrogen was found in all samples studied. The amount varied considerably, depending on soil maturity, mineral types present, grain size distribution, and depth. Hydrogen implantation is definitely a surface phenomenon. However, as constructional particles are formed, previously exposed surfaces become embedded within particles, causing an enrichment of hydrogen in these species. In view of possibly extracting the hydrogen for use on the lunar surface, it is encouraging to know that hydrogen is present to a considerable depth and not only in the upper few millimeters. Based on these preliminary studies, extraction of solar wind hydrogen from lunar soil appears feasible, particulary if some kind of grain size separation is possible.

  8. Plant species distribution in relation to water-table depth and soil redox potential in montane riparian meadows

    Science.gov (United States)

    Kathleen A. Dwire; J. Boone Kauffman; John E. Baham

    2006-01-01

    The distribution of riparian plant species is largely driven by hydrologic and soil variables, and riparian plant communities frequently occur in relatively distinct zones along streamside elevational and soil textural gradients. In two montane meadows in northeast Oregon, USA, we examined plant species distribution in three riparian plant communities¡ªdefined as wet,...

  9. Atom and carrier depth distributions for 300 keV arsenic channeled in the of silicon as a function of alignment angle and ion fluence

    International Nuclear Information System (INIS)

    Wilson, R.G.

    1980-01-01

    Depth distributions of As atoms measured by SIMS, and of associated carriers measured by differential C-V, both give a measured most probable channeling range Rsub(c) of 3.35 to 3.40 μm for 300 keV As ions implanted in the of Si, aligned within approximately 0.05 deg (proper or axial channeling). The As ion fluences used were 3.0 x 10 13 and 1.0 x 10 14 , and 1.5 x 10 12 cm -2 , for the SIMS and C-V, respectively, and the lowest atom and carrier densities measured in the profiles were 1 x 10 15 and 1 x 10 14 cm -3 , respectively. The maximum or saturated As density measured at Rsub(c) was approximately 1.5 x 10 16 cm -3 . The depth distribution for 0.50 deg misalignment from the differed only slightly, probably within the experimental measurement reproducibility, and the Rsub(c) was still approximately 3.4 μm. Atom and carrier depth distributions are also shown for misalignment angles of 1.0 and 2.0 deg from the of Si and are significantly degraded. Comparison of the SIMS profiles shows that channeling has saturated by the time an ion fluence of 3 x 10 13 cm -2 is reached. No significant redistribution of channeled As atoms occurs upon annealing at 800 0 C for 30 min. (author)

  10. Predictive modelling of habitat use by marine predators with respect to the abundance and depth distribution of pelagic prey

    Science.gov (United States)

    Boyd, Charlotte; Castillo, Ramiro; Hunt, George L.; Punt, André E..; VanBlaricom, Glenn R.; Weimerskirch, Henri; Bertrand, Sophie

    2015-01-01

    Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey.

  11. The effect of depth, distance from dam and habitat on spatial distribution of fish in an artificial reservoir

    Czech Academy of Sciences Publication Activity Database

    Prchalová, Marie; Kubečka, Jan; Čech, Martin; Frouzová, Jaroslava; Draštík, Vladislav; Hohausová, Eva; Jůza, Tomáš; Kratochvíl, Michal; Matěna, Josef; Peterka, Jiří; Říha, Milan; Tušer, Michal; Vašek, Mojmír

    2009-01-01

    Roč. 18, č. 2 (2009), s. 247-260 ISSN 0906-6691 R&D Projects: GA AV ČR(CZ) 1QS600170504; GA ČR(CZ) GA206/07/1392; GA MZe(CZ) QH81046 Institutional research plan: CEZ:AV0Z60170517 Keywords : horizontal distribution * vertical distribution * gillnet * reservoir * Cyprinidae * Percidae * redundancy analysis Subject RIV: EH - Ecology, Behaviour Impact factor: 1.512, year: 2009

  12. Development of a high-efficiency hydrogen generator for fuel cells for distributed power generation

    Energy Technology Data Exchange (ETDEWEB)

    Duraiswamy, K.; Chellappa, Anand [Intelligent Energy, 2955 Redondo Ave., Long Beach, CA 90806 (United States); Smith, Gregory; Liu, Yi; Li, Mingheng [Department of Chemical and Materials Engineering, California State Polytechnic University, Pomona, CA 91768 (United States)

    2010-09-15

    A collaborative effort between Intelligent Energy and Cal Poly Pomona has developed an adsorption enhanced reformer (AER) for hydrogen generation for use in conjunction with fuel cells in small sizes. The AER operates at a lower temperature (about 500 C) and has a higher hydrogen yield and purity than those in the conventional steam reforming. It employs ceria supported rhodium as the catalyst and potassium-promoted hydrotalcites to remove carbon dioxide from the products. A novel pulsing feed concept is developed for the AER operation to allow a deeper conversion of the feedstock to hydrogen. Continuous production of near fuel-cell grade hydrogen is demonstrated in the AER with four packed beds running alternately. In the best case of methane reforming, the overall conversion to hydrogen is 92% while the carbon dioxide and carbon monoxide concentrations in the production stream are on the ppm level. The ratio of carbon dioxide in the regeneration exhaust to the one in the product stream is on the order of 10{sup 3}. (author)

  13. Influence of spatial and temporal spot distribution on the ocular surface quality and maximum ablation depth after photoablation with a 1050 Hz excimer laser system.

    Science.gov (United States)

    Mrochen, Michael; Schelling, Urs; Wuellner, Christian; Donitzky, Christof

    2009-02-01

    To investigate the effect of temporal and spatial distributions of laser spots (scan sequences) on the corneal surface quality after ablation and the maximum ablation of a given refractive correction after photoablation with a high-repetition-rate scanning-spot laser. IROC AG, Zurich, Switzerland, and WaveLight AG, Erlangen, Germany. Bovine corneas and poly(methyl methacrylate) (PMMA) plates were photoablated using a 1050 Hz excimer laser prototype for corneal laser surgery. Four temporal and spatial spot distributions (scan sequences) with different temporal overlapping factors were created for 3 myopic, 3 hyperopic, and 3 phototherapeutic keratectomy ablation profiles. Surface quality and maximum ablation depth were measured using a surface profiling system. The surface quality factor increased (rough surfaces) as the amount of temporal overlapping in the scan sequence and the amount of correction increased. The rise in surface quality factor was less for bovine corneas than for PMMA. The scan sequence might cause systematic substructures at the surface of the ablated material depending on the overlapping factor. The maximum ablation varied within the scan sequence. The temporal and spatial distribution of the laser spots (scan sequence) during a corneal laser procedure affected the surface quality and maximum ablation depth of the ablation profile. Corneal laser surgery could theoretically benefit from smaller spot sizes and higher repetition rates. The temporal and spatial spot distributions are relevant to achieving these aims.

  14. Depth Distribution Studies of Carbon in Steel Surfaces by Means of Charged Particle Activation Analysis with an Account of Heat and Diffusion Effects in the Sample

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D; Lorenzen, J [AB Atomenergi, Nykoeping (Sweden); Witalis, E [Swedish National Defence Research Inst., Stockholm (Sweden)

    1972-05-15

    Depth distribution studies of carbon in steel and iron were carried out in the concentration range 0.05-1 %, using proton activation analysis. Surface content studies were performed in the concentration range 0.01-1 % using deuteron activation analysis. The following reactions were utilized: {sup 12}C(p,{gamma}){sup 13}N and {sup 12}C(d,n){sup 13}N Evaluations of depth distribution were based on resonances in the excitation function. The carbon content was determined with the aid of the positron emitter, {sup 13}N, using either single-peak or coincidence measurements. The heat dissipation in the irradiated region of the samples was calculated, and the temperature rise was measured using thermocouples. The temperature distribution within the hot zone subjected to irradiation by charged particles, together with the temperature distribution around this zone, was studied in order to estimate any effect this might have on the carbon diffusion. A device for automatic sample exchange which is remotely controlled is described.

  15. Depth and substrate as determinants of distribution of juvenile flathead sole (Hippoglossoides elassodon) and rock sole (Pleuronectes bilineatus), in Kachemak Bay, Alaska

    Science.gov (United States)

    Abookire, Alisa A.; Norcross, Brenda L.

    1998-01-01

    Three transects in Kachemak Bay, Alaska, were sampled in September 1994, May and August 1995, and February, May, and August 1996. Juvenile flathead sole, Hippoglossoides elassodon, and rock sole, Pleuronectes bilineatus, were the most abundant flatfishes, comprising 65-85% of all fiatfishes captured at any period. Collections of fish and sediments were made at regular depth contour intervals of l0 m. Habitat distribution was described by depth at 10 m increments and sediment percent weights of gravel, sand, and mud. Year-round habitat of flathead sole age-0 was primarily from 40 to 60 m, and age-1 habitat was primarily from 40 to 80 m. Summer habitat of rock sole age-0 and -1 was from 10 to 30 m, and in winter they moved offshore to depths of up to 150 m. Both age classes of flathead sole were most abundant on mixed mud sediments, while age-1 were also in high abundance on muddy sand sediments. Rock sole age-0 and -1 were most abundant on sand, though age-1 were also found on a variety of sediments both finer and coarser grained than sand. Flathead sole and rock sole had distinctive depth and sediment habitats. When habitat overlap occurred between the species, it was most often due to rock sole moving offshore in the winter. Abundances were not significantly different among seasons for age-1 flatfishes.

  16. Challenges in the transition toward a hydrogen-based society. An in-depth study to assess the potential of a transition to a hydrogen-based energy supply in Europe

    International Nuclear Information System (INIS)

    Mourik, R.; De Groot, A.; Jeeninga, H.

    2006-12-01

    The Hysociety project, financed under the FP5 framework of the European Commission, aimed to contribute to European policies on hydrogen-related issues through the development of an action plan for the introduction of hydrogen. The geographic target was Europe, focusing on the 15 European Union member states, plus Norway and Iceland. In addition, demonstration projects in Canada, the United States, Japan, Brazil, and China were analyzed. Work package 1 addressed the technological, infrastructural, ecological, economic, political, and cultural challenges of the transition to a hydrogen-based society. The work built upon an analysis of the challenges identified in demonstration projects in all participating countries. In this article we first discuss the transition theory and the methodology used in Hysociety work package 1 and conclude with a discussion of results of the Hysociety project

  17. The dependence of skin lesions on the depth-dose distribution from β-irradiation of people in the Chernobyl nuclear power plant accident

    International Nuclear Information System (INIS)

    Barabanova, A.

    1990-01-01

    A detailed study was made of conditions of exposure of 56 Chernobyl victims who suffered skin radiation lesions. The most typical conditions were experimentally reconstructed to investigate specific characteristics of dose distribution to the skin according to depth for different exposure conditions. Absorbed doses at depths of 7 mg cm -2 and 150 mg cm -2 were calculated on the basis of measurements with multilayer skin dosemeters. Patients were classified into four groups. Dosimetric characteristics for each group were compared with clinical pictures to establish critical factors in the occurrence of lesions. It was demonstrated that depth-dose distribution of β-radiation to the skin is of great influence not only for early effects of radiation but also for later effects. Radiation lesions in the skin led to death if the area of the lesions exceeded about 50% total body surface, and if doses to the skin were about 200-300 Gy at 7 mg cm -2 and more than about 30 Gy at 150 mg cm -2 . (author)

  18. The 14N(d,0)15N nuclear reaction method for nitrogen depth distribution measurements in wheat and barley

    International Nuclear Information System (INIS)

    Goenczi, L.; Didriksson, R.; Berggren, H.; Sundqvist, B.; Lindh, U.; Awal, M.A.

    1980-01-01

    The 14 N(d,p 0 ) 15 N reaction has been used to measure nitrogen depth distributions in single grains of wheat and barley. With the beam energy used (6 MeV) a depth of 225 μm was reached. In order to test the applicability of the method for plant breeding purposes we have studied 1000 grains of wheat and grains of barley, which are part of a larger material of about 50 000 grains grown and harvested under controlled biological conditions. The measured nitrogen distributions in wheat show striking correlations with parameters describing the nitrogen level of fertilizer, the time of harvesting, the grain position in a head and the analyzed variety of wheat. Contributions to the spectra from silicon in the hull of barley are demonstrated. Contributions from interfering elements in the aleuron layer in wheat placed a limit of 120 μm to the depth region analyzed. The importance of effects like pileup, heating of the grains by the beam and grain asymmetries were studied in detail. The possibility to use the technique for selection purposes in plant breeding will be discussed. (author)

  19. A Novel Hybrid Reformer-Electrolyzer-Purifier (REP) for Distributed Production of Low-Cost, Low Greenhouse Gas Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Fred C. [FuelCell Energy, Inc., Danbury, CT (United States)

    2017-03-28

    FuelCell Energy with support from the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) has investigated the production of low-cost, low CO2 hydrogen using a molten carbonate fuel cell operating as an electrolyzer. We confirmed the feasibility of the technology by testing a large-scale short stack. Economic analysis was done with the assistance of the National Fuel Cell Center at the University of California, Irvine and we found the technology to be attractive, especially for distributed hydrogen. We explored the performance under various operating parameters and developed an accurate model for further analysis and development calculations. We achieved the expected results, meeting all program goals. We identified additional uses of the technology such as for CO2 capture, power storage, and power load leveling.

  20. SOAR on Containment Thermal-hydraulics and Hydrogen Distribution - Prepared by an OECD/NEA Group of Experts

    International Nuclear Information System (INIS)

    Karwat, Helmut; Bardelay, Joel; Hashimoto, Takashi; Koroll, Grant W.; Krause, Matt; L'Heriteau, Jean-Pierre; Lundstroem, Petra; Notafrancesco, Allen; Royl, Peter; Schwinges, Bernd; Tezuka, Hiroko; Tills, Jack; Royen, Jacques

    1999-06-01

    During the course of severe accidents in water-cooled nuclear power plants, large amounts of hydrogen could be generated and released into the containment. The formation of hydrogen inevitably accompanies any core degradation process. The problem may be amplified by the less-likely core-concrete interaction during a subsequent basemat erosion. The integrity of the containment could be challenged by certain hydrogen combustion modes if no mitigative measures were available. International consensus is that a detailed knowledge of containment thermal-hydraulics is necessary to analyse the effectiveness of hydrogen mitigation methods, even though, at present, there are no generally accepted requirements for this purpose. During the last decade, considerable international efforts have been undertaken to better understand the associated problems by executing a large number of experiments and subjecting the test results to extensive analytical assessment. The CSNI Principal Working Group 4 at its meeting in September 1995 proposed to CSNI to draft a state-of-the-art-report (SOAR) on 'Containment Thermal-hydraulics and Hydrogen Distribution'. CSNI had endorsed the preparation of such a SOAR at its November 1995 meeting. The mandate for this SOAR can be best illustrated by several guiding questions that had been raised and discussed during earlier meetings of PWG4 and its Task Group on Severe Accident Phenomena in Containment (SAC): - What had been learnt from recent International Standard Problem (ISP) exercises on containment thermal-hydraulics and hydrogen distribution? - What could be concluded about the codes' abilities to predict the containment thermal behaviour from ISPs and from other related tests for plant application? - How should remaining uncertainties be best handled? - What more needs to be done, if anything? Consequently, the main objectives of this SOAR are: 1. to assess the current capabilities to make relevant predictions for the plant assessment of

  1. Study of the distribution of hydrogen in a PWR containment with CFD codes; Estudio de la distribucion de hidrogeno en una contencion PWR con codigos CFD

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, G.; Matias, R.; Fernandez, K.; Justo, D.; Bocanegra, R.; Mena, L.; Queral, C.

    2015-07-01

    During a severe accident in a PWR, the hydrogen generated may be distributed in the containment atmosphere and reach the combustion conditions that can cause the containment failure. In this research project, a preliminary study has been done about the capacities of ANSYS Fluent 15.0 and GOTHIC 8.0 to tri dimensional distribution of the hydrogen in a PWR containment during a severe accident. (Author)

  2. The influence of a spatial displacement of hydrogen on the reactivity and neutron flux density distribution in a ZrH-moderated reactor

    International Nuclear Information System (INIS)

    Doehler, J.; Bartsch, G.

    1975-08-01

    The effect of changes of the hydrogen concentration in uranium zirconium hydride resulting from spatially varying temperatures on the reactivity and neutron flux distribution of the BER-II core (power 2.2 MW) are shown. Furthermore, in general, the influence of the hydrogen concentration on important reactor parameters of a fuel cell of BER-II is calculated and presented. A comparison of the diffusion calculation with spatially constant hydrogen concentrations shows a decrease of the thermal neutron flux density in regions with a low hydrogen content (high temperature) and inversely an increase for high hydrogen concentrations. Furthermore, a change of the effective multiplication factor by 0.6% was found in the case of a spatially varying hydrogen concentration as compared with the calculation for a constant concentration. (orig.) [de

  3. Weighted halfspace depth

    Czech Academy of Sciences Publication Activity Database

    Kotík, Lukáš; Hlubinka, D.; Vencálek, O.

    Vol. 46, č. 1 (2010), s. 125-148 ISSN 0023-5954 Institutional research plan: CEZ:AV0Z10750506 Keywords : data depth * nonparametric multivariate analysis * strong consistency of depth * mixture of distributions Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.461, year: 2010 http://library.utia.cas.cz/separaty/2010/SI/kotik-weighted halfspace depth.pdf

  4. SPIRAL STRUCTURE OF M51 - DISTRIBUTION AND KINEMATICS OF THE ATOMIC AND IONIZED HYDROGEN

    NARCIS (Netherlands)

    TILANUS, RPJ; ALLEN, RJ

    The atomic hydrogen (H I) and the H-alpha emission lines in the grand-design spiral galaxy M51 have been observed with the Westerbork Synthesis Radio Telescope and the TAURUS Fabry-Perot imaging spectrometer, respectively. Across the inner spiral arms significant tangential and radial velocity

  5. Analysis of the distribution of hydrogen in the containment drywell CN Cofrentes; Analisis de la distribucion de hidrogeno en contencion y pozo seco de C. N. Cofrentes

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M. C.; Serrano, C.; Gonzalez, M.; Jimenez, G.; Lopez-Alonso, E.

    2014-07-01

    The development model of the containment CN Cofrentes by GOTHIC was carried out by introducing all geometric and Containment data structures, thus being able to model all the interior spaces and rooms that compose it. Thus we have obtained a detailed 3D model with sufficient accuracy to the global study of hydrogen management, allowing to take into account, when the distribution of hydrogen, both asymmetric containment as downloads mass and energy in it are made, allowing to simulate the distribution of steam and hydrogen present in the severe accident to determine the areas of greatest risk of deflagration or detonation during the evolution of the accident. (Author)

  6. Distribution of axial length, anterior chamber depth, and corneal curvature in an aged population in South China.

    Science.gov (United States)

    Chen, Hui; Lin, Haotian; Lin, Zhuoling; Chen, Jingjing; Chen, Weirong

    2016-05-01

    Ocular biometry is important for preoperative assessment in cataract and anterior segment surgery. The purpose of this study was to investigate normative ocular biometric parameters and their associations in an older Chinese population. This was a cross-sectional observational study. From 2013 to 2014, we recruited inhabitants aged 50 years or older in Guangzhou, China. Among 1,117 participants in the study, data from 1,015 phakic right eyes were used for analyses. Ocular parameters including axial length (AL), anterior chamber depth (ACD), and corneal curvature (K) were measured using an IOL Master. The mean AL, ACD, and K were 23.48 mm [95 % confidence interval (CI), 23.40-23.55], 3.03 mm (CI, 3.01-3.05), and 44.20 mm (CI, 44.11-44.29), respectively. A mean reduction in ACD with age was observed (P = 0.002) in male subjects but not in female subjects (P = 0.558). Male subjects had significantly longer ALs (23.68 mm versus 23.23 mm, P population in South China. The AL in this Chinese cohort was greater than that observed in the Singaporean Chinese but smaller than that observed in Malaysia and for Caucasians. The Chinese have a shallower ACD than some other racial groups. Age and sex were the most consistent predictors of ocular biometry in the older population from South China.

  7. Using High-Resolution Satellite Aerosol Optical Depth To Estimate Daily PM2.5 Geographical Distribution in Mexico City.

    Science.gov (United States)

    Just, Allan C; Wright, Robert O; Schwartz, Joel; Coull, Brent A; Baccarelli, Andrea A; Tellez-Rojo, Martha María; Moody, Emily; Wang, Yujie; Lyapustin, Alexei; Kloog, Itai

    2015-07-21

    Recent advances in estimating fine particle (PM2.5) ambient concentrations use daily satellite measurements of aerosol optical depth (AOD) for spatially and temporally resolved exposure estimates. Mexico City is a dense megacity that differs from other previously modeled regions in several ways: it has bright land surfaces, a distinctive climatological cycle, and an elevated semi-enclosed air basin with a unique planetary boundary layer dynamic. We extend our previous satellite methodology to the Mexico City area, a region with higher PM2.5 than most U.S. and European urban areas. Using a novel 1 km resolution AOD product from the MODIS instrument, we constructed daily predictions across the greater Mexico City area for 2004-2014. We calibrated the association of AOD to PM2.5 daily using municipal ground monitors, land use, and meteorological features. Predictions used spatial and temporal smoothing to estimate AOD when satellite data were missing. Our model performed well, resulting in an out-of-sample cross-validation R(2) of 0.724. Cross-validated root-mean-squared prediction error (RMSPE) of the model was 5.55 μg/m(3). This novel model reconstructs long- and short-term spatially resolved exposure to PM2.5 for epidemiological studies in Mexico City.

  8. Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

    Energy Technology Data Exchange (ETDEWEB)

    Ocampo, R.; Bauder, C.; Callot, H.J.; Albrecht, P. (Univ. Louis Pasteur, Strasbourg (France))

    1992-02-01

    The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry, and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3), and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical Treibs scheme,' including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

  9. Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

    Science.gov (United States)

    Ocampo, Rubén; Bauder, Claude; Callot, Henry J.; Albrecht, Pierre

    1992-02-01

    The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3) and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical "Treibs scheme," including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

  10. Final Technical Report: Hawaii Hydrogen Center for Development and Deployment of Distributed Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rocheleau, Richard E.

    2008-09-30

    Hydrogen power park experiments in Hawai‘i produced real-world data on the performance of commercialized electrochemical components and power systems integrating renewable and hydrogen technologies. By analyzing the different losses associated with the various equipment items involved, this work identifies the different improvements necessary to increase the viability of these technologies for commercial deployment. The stand-alone power system installed at Kahua Ranch on the Big Island of Hawaii required the development of the necessary tools to connect, manage and monitor such a system. It also helped the electrolyzer supplier to adapt its unit to the stand-alone power system application. Hydrogen fuel purity assessments conducted at the Hawai‘i Natural Energy Institute (HNEI) fuel cell test facility yielded additional knowledge regarding fuel cell performance degradation due to exposure to several different fuel contaminants. In addition, a novel fitting strategy was developed to permit accurate separation of the degradation of fuel cell performance due to fuel impurities from other losses. A specific standard MEA and a standard flow field were selected for use in future small-scale fuel cell experiments. Renewable hydrogen production research was conducted using photoelectrochemical (PEC) devices, hydrogen production from biomass, and biohydrogen analysis. PEC device activities explored novel configurations of ‘traditional’ photovoltaic materials for application in high-efficiency photoelectrolysis for solar hydrogen production. The model systems investigated involved combinations of copper-indium-gallium-diselenide (CIGS) and hydrogenated amorphous silicon (a-Si:H). A key result of this work was the establishment of a robust “three-stage” fabrication process at HNEI for high-efficiency CIGS thin film solar cells. The other key accomplishment was the development of models, designs and prototypes of novel ‘four-terminal’ devices integrating high

  11. Quantitative AMS depth profiling of the hydrogen isotopes collected in graphite divertor and wall tiles of the tokamak ASDEX-Upgrade

    International Nuclear Information System (INIS)

    Sun, G.Y.; Friedrich, M.; Groetzschel, R.; Buerger, W.; Behrisch, R.; Garcia-Rosales, C.

    1997-01-01

    The accelerator mass spectrometry (AMS) facility at the 3 MV Tandetron in Rossendorf has been applied for quantitative depth profiling of deuterium and tritium in samples cut from graphite protection tiles at the vessel walls of the fusion experiment ASDEX-Upgrade at the Max-Planck-Institut fuer Plasmaphysik in Garching. The tritium originates from D(d,p)T fusion reactions in the plasma and it is implanted in the vessel walls together with deuterium atoms and ions from the plasma. The T concentrations in the surface layers down to the analyzing depth of about 25 μm are in the range of 10 11 to 5 x 10 15 T-atoms/cm 3 corresponding to a tritium retention of 3 x 10 10 to 3.5 x 10 12 T-atoms/cm 2 . The much higher deuterium concentrations in the samples were simultaneously measured by calibrated conventional SIMS. In the surface layers down to the analyzing depth of about 25 μm the deuterium concentrations are between 3 x 10 18 and 8 x 10 21 atoms/cm 3 , corresponding to a deuterium retention of 2.5 x 10 16 to 2.5 x 10 18 atoms/cm 2 The estimated total amount of tritium in the vessel walls is of the same order of magnitude as the total number of neutrons produced in D(d,n) 3 He reactions. (orig.)

  12. HMS-burn: a model for hydrogen distribution and combustion in nuclear reactor containments

    International Nuclear Information System (INIS)

    Travis, J.R.

    1985-01-01

    It is now possible to analyze the time-dependent, fully three-dimensional behavior of hydrogen combustion in nuclear reactor containments. This analysis involves coupling the full Navier-Stokes equations with multi-species transport to the global chemical kinetics of hydrogen combustion. A transport equation for the subgrid scale turbulent kinetic energy density is solved to produce the time and space dependent turbulent transport coefficients. The heat transfer coefficient governing the exchange of heat between fluid computational cells adjacent to wall cells is calculated by a modified Reynolds analogy formulation. The analysis of a MARK-III containment indicates very complex flow patterns that greatly influence fluid and wall temperatures and heat fluxes

  13. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation

    Science.gov (United States)

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-10-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System.

  14. Absolute atomic hydrogen density distribution in a hollow cathode discharge by two-photon polarization spectroscopy

    International Nuclear Information System (INIS)

    Gonzalo, A B; Rosa, M I de la; Perez, C; Mar, S; Gruetzmacher, K

    2004-01-01

    We report on quantitative measurements of ground-state atomic hydrogen densities in a stationary plasma far off thermodynamic equilibrium, generated in a hollow cathode discharge, by two-photon polarization spectroscopy via the 1S-2S transition. Absolute densities are obtained using a well established calibration method based on the non-resonant two-photon polarization signal of xenon gas at room temperature, which serves as the reference at the wavelength of the hydrogen transition. This study is dedicated to demonstrating the capability of two-photon polarization spectroscopy close to the detection limit. Therefore, it requires single-longitudinal mode UV-laser radiation provided by an advanced UV-laser spectrometer

  15. Distribution of short block copolymer chains in Binary Blends of Block Copolymers Having Hydrogen Bonding

    Science.gov (United States)

    Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon

    2014-03-01

    A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.

  16. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation

    OpenAIRE

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, Fran?ois; Leroux, Hugues; Vezin, Herv?; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-01-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of elec...

  17. Applications of nuclear reaction analysis for determining hydrogen and deuterium distribution in metals

    International Nuclear Information System (INIS)

    Altstetter, C.J.

    1981-01-01

    The use of ion beams for materials analysis has made a successful transition from the domain of the particle physicist to that of the materials scientist. The subcategory of this field, nuclear reaction analysis, is just now undergoing the transition, particularly in applications to hydrogen in materials. The materials scientist must locate the nearest accelerator, because now he will find that using it can solve mysteries that do not yield to other techniques. 9 figures

  18. Distributed H2 Supply for Fuel Cell Utility Vehicles Year 6 - Activity 3.5 - Development fo a National Center for Hydrogen Technology

    Energy Technology Data Exchange (ETDEWEB)

    Almlie, Jay

    2012-04-15

    The Energy & Environmental Research Center (EERC) has developed a high-pressure hydrogen production system that reforms a liquid organic feedstock and water at operating pressures up to 800 bar (~12,000 psig). The advantages of this system include the elimination of energy-intensive hydrogen compression, a smaller process footprint, and the elimination of gaseous or liquid hydrogen transport. This system could also potentially enable distributed hydrogen production from centralized coal. Processes have been investigated to gasify coal and then convert the syngas into alcohol or alkanes. These alcohols and alkanes could then be easily transported in bulk to distributed high-pressure water-reforming (HPWR)-based systems to deliver hydrogen economically. The intent of this activity was to utilize the EERC’s existing HPWR hydrogen production process, previously designed and constructed in a prior project phase, as a basis to improve operational and production performance of an existing demonstration unit. Parameters to be pursued included higher hydrogen delivery pressure, higher hydrogen production rates, and the ability to refill within a 5-minute time frame.

  19. Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    Energy Technology Data Exchange (ETDEWEB)

    Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Tolj, I.; Davids, M.W.; Bujlo, P. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Smith, F. [Impala Platinum Ltd, Springs (South Africa); Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB{sub 2}-type MH material (H{sub 2} equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H{sub 2} charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H{sub 2} consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system.

  20. Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    International Nuclear Information System (INIS)

    Lototskyy, M.; Tolj, I.; Davids, M.W.; Bujlo, P.; Smith, F.; Pollet, B.G.

    2015-01-01

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB 2 -type MH material (H 2 equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H 2 charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H 2 consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system

  1. Multi-objective stochastic distribution feeder reconfiguration problem considering hydrogen and thermal energy production by fuel cell power plants

    International Nuclear Information System (INIS)

    Niknam, Taher; Kavousi Fard, Abdollah; Baziar, Aliasghar

    2012-01-01

    This paper assesses the operation and management of electrical energy, hydrogen production and thermal load supplement by the Fuel Cell Power Plants (FCPP) in the distribution systems with regard to the uncertainties which exist in the load demand as well as the price of buying natural gas for FCPPs, fuel cost for residential loads, tariff for purchasing electricity, tariff for selling electricity, hydrogen selling price, operation and maintenance cost and the price of purchasing power from the grid. Therefore, a new modified multi-objective optimization algorithm called Teacher-Learning Algorithm (TLA) is proposed to integrate the optimal operation management of Proton Exchange Membrane FCPPs (PEM-FCPPs) and the optimal configuration of the system through an economic model of the PEM-FCPP. In order to improve the total ability of TLA for global search and exploration, a new modification process is suggested such that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated power systems, in this paper for the first time, the DFR problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to see the feasibility and the superiority of the proposed method, a standard test system is investigated as the case study. The simulation results are investigated in four different scenarios to show the effect of hydrogen production and thermal recovery more evidently. -- Highlights: ► Present an economical and thermal modeling of PEM-FCPPs. ► Present an approach for optimal operation of PEM-FCPPs in a stochastic environment. ► Consider benefits of thermal recovery and Hydrogen production for PEM-FCPPs. ► Present several scenarios for management of PEM-FCPPs.

  2. Calculation of the displacement cross sections and the DPA distribution in hydrogenated amorphous silicon semiconductors detectors in medical digital imaging applications

    International Nuclear Information System (INIS)

    Leyva Fabelo, Antonio; Piñera Hernández, Ibrahin; Shtejer Díaz, Katerin; Abreu Alfonso, Yamiel; Cruz Inclán, Carlos Manuel

    2007-01-01

    In present paper the dependence of the displacement cross sections of the different species of atoms in the a-Si:H structure, with the energy of the secondary electrons generated by the X-rays of the typical energies using in medical imaging applications, was calculated using the Mott-McKinley- Feshbach approach. It was verified that for electron energies higher than 1.52 keV it is possible the occurrence of hydrogen atoms displacements, while for the silicon atoms the threshold energy is 126 keV. These results were compared with those obtained for similar detectors but developed with crystalline silicon. With the use of the mathematical simulation of the radiation transport in the matter, the energy spectrum of the secondary electrons was calculated in order to estimate the number of atomic displacements, which take place in the semiconducting amorphous device in working regime. The spatial distribution of the dpa in the detectors volume, as well as its behavior with the depth in the work region are presented and discussed in the text. (author)

  3. A new Liopropoma sea bass (Serranidae, Epinephelinae, Liopropomini) from deep reefs off Curaçao, southern Caribbean, with comments on depth distributions of western Atlantic liopropomins

    Science.gov (United States)

    Baldwin, Carole C.; Robertson, D. Ross

    2014-01-01

    Collecting reef-fish specimens using a manned submersible diving to 300 m off Curaçao, southern Caribbean, is resulting in the discovery of numerous new fish species. The new Liopropoma sea bass described here differs from other western Atlantic members of the genus in having VIII, 13 dorsal-fin rays; a moderately indented dorsal-fin margin; a yellow-orange stripe along the entire upper lip; a series of approximately 13 white, chevron-shaped markings on the ventral portion of the trunk; and a reddish-black blotch on the tip of the lower caudal-fin lobe. The new species, with predominantly yellow body and fins, closely resembles the other two “golden basses” found together with it at Curaçao: L. aberransand L. olneyi. It also shares morphological features with the other western Atlantic liopropomin genus,Bathyanthias. Preliminary phylogenetic data suggest that western Atlantic liopropomins, includingBathyanthias, are monophyletic with respect to Indo-Pacific Liopropoma, and that Bathyanthias is nested within Liopropoma, indicating a need for further study of the generic limits of Liopropoma. The phylogenetic data also suggest that western Atlantic liopropomins comprise three monophyletic clades that have overlapping depth distributions but different depth maxima (3–135 m, 30–150 m, 133–411 m). The new species has the deepest depth range (182–241 m) of any known western Atlantic Liopropomaspecies. Both allopatric and depth-mediated ecological speciation may have contributed to the evolution of western Atlantic Liopropomini.

  4. The P{sub 1}-approximation for the Distribution of Neutrons from a Pulsed Source in Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, A

    1963-12-15

    The asymptotic distribution of neutrons from a pulsed, high energy source in an infinite moderator has been obtained earlier in a 'diffusion' approximation. In that paper the cross section was assumed to be constant over the whole energy region and the time derivative of the first moment was disregarded. Here, first, an analytic expression is obtained for the density in a P{sub 1} -approximation. However, the result is very complicated, and it is shown that an asymptotic solution can be found in a simpler way. By taking into account the low hydrogen scattering cross section at the source energy it follows that the space dependence of the distribution is less than that obtained earlier. The importance of keeping the time derivative of the first moment is further shown in a perturbation approximation.

  5. Determination of the parton distributions and structure functions of the proton from neutrino and antineutrino reactions on hydrogen and deuterium

    Science.gov (United States)

    Jones, G. T.; Jones, R. W. L.; Kennedy, B. W.; Klein, H.; Morrison, D. R. O.; Wachsmuth, H.; Miller, D. B.; Mobayyen, M. M.; Wainstein, S.; Aderholz, M.; Hantke, D.; Katz, U. F.; Kern, J.; Schmitz, N.; Wittek, W.; Borner, H. P.; Myatt, G.; Cooper-Sarkar, A. M.; Guy, J.; Venus, W.; Bullock, F. W.; Burke, S.

    1994-12-01

    This analysis is based on data from neutrino and antineutrino scattering on hydrogen and deuterium, obtained with BEBC in the (anti) neutrino wideband beam of the CERN SPS. The parton momentum distributions in the proton and the proton structure functions are determined in the range 0.01distributions. The QCD predictions are taken into account using the Altarelli-Parisi equations, with a resulting scale parameter 10052_2005_Article_BF01574161_TeX2GIFE1.gif Λ = left( {192 ± 40(stat.) ± {}_{108}^{222} (syst.)} right)MeV.

  6. Hexicon 2: automated processing of hydrogen-deuterium exchange mass spectrometry data with improved deuteration distribution estimation.

    Science.gov (United States)

    Lindner, Robert; Lou, Xinghua; Reinstein, Jochen; Shoeman, Robert L; Hamprecht, Fred A; Winkler, Andreas

    2014-06-01

    Hydrogen-deuterium exchange (HDX) experiments analyzed by mass spectrometry (MS) provide information about the dynamics and the solvent accessibility of protein backbone amide hydrogen atoms. Continuous improvement of MS instrumentation has contributed to the increasing popularity of this method; however, comprehensive automated data analysis is only beginning to mature. We present Hexicon 2, an automated pipeline for data analysis and visualization based on the previously published program Hexicon (Lou et al. 2010). Hexicon 2 employs the sensitive NITPICK peak detection algorithm of its predecessor in a divide-and-conquer strategy and adds new features, such as chromatogram alignment and improved peptide sequence assignment. The unique feature of deuteration distribution estimation was retained in Hexicon 2 and improved using an iterative deconvolution algorithm that is robust even to noisy data. In addition, Hexicon 2 provides a data browser that facilitates quality control and provides convenient access to common data visualization tasks. Analysis of a benchmark dataset demonstrates superior performance of Hexicon 2 compared with its predecessor in terms of deuteration centroid recovery and deuteration distribution estimation. Hexicon 2 greatly reduces data analysis time compared with manual analysis, whereas the increased number of peptides provides redundant coverage of the entire protein sequence. Hexicon 2 is a standalone application available free of charge under http://hx2.mpimf-heidelberg.mpg.de.

  7. Hexicon 2: Automated Processing of Hydrogen-Deuterium Exchange Mass Spectrometry Data with Improved Deuteration Distribution Estimation

    Science.gov (United States)

    Lindner, Robert; Lou, Xinghua; Reinstein, Jochen; Shoeman, Robert L.; Hamprecht, Fred A.; Winkler, Andreas

    2014-06-01

    Hydrogen-deuterium exchange (HDX) experiments analyzed by mass spectrometry (MS) provide information about the dynamics and the solvent accessibility of protein backbone amide hydrogen atoms. Continuous improvement of MS instrumentation has contributed to the increasing popularity of this method; however, comprehensive automated data analysis is only beginning to mature. We present Hexicon 2, an automated pipeline for data analysis and visualization based on the previously published program Hexicon (Lou et al. 2010). Hexicon 2 employs the sensitive NITPICK peak detection algorithm of its predecessor in a divide-and-conquer strategy and adds new features, such as chromatogram alignment and improved peptide sequence assignment. The unique feature of deuteration distribution estimation was retained in Hexicon 2 and improved using an iterative deconvolution algorithm that is robust even to noisy data. In addition, Hexicon 2 provides a data browser that facilitates quality control and provides convenient access to common data visualization tasks. Analysis of a benchmark dataset demonstrates superior performance of Hexicon 2 compared with its predecessor in terms of deuteration centroid recovery and deuteration distribution estimation. Hexicon 2 greatly reduces data analysis time compared with manual analysis, whereas the increased number of peptides provides redundant coverage of the entire protein sequence. Hexicon 2 is a standalone application available free of charge under http://hx2.mpimf-heidelberg.mpg.de.

  8. Distribution of mean surface stable isotopes values in east Antarctica; observed changes with depth in coastal area

    International Nuclear Information System (INIS)

    Lorius, C.; Merlivat, L.

    1975-01-01

    Mean samples of the snow accumulated during the last ten years have been collected at 48 stations distributed along a 850km long axis in East Antarctica, starting from Dumont d'Urville towards Vostok. Up to 1000m elevations the mean deuterium values are rather constant (-150 per thousand); then they decrease with various parameters (distance, elevation) and in particular with the mean annual temperatures, according to a linear relationship (D per thousand=6,04T(degC)-51) for a temperature range from -20 to -55 deg C. The observed D per thousand-O per thousand relationship is discussed. Measurements along a 303m deep core (down to the bedrock) obtained in the control area show very large D changes with mean values varying between -150 and -360 per thousand; this last value characterizes present surface snow deposited about 800km upstream. The observed D variations may be explained by changes in the site of origin of the ice; mechanisms which could explain the presence of ice originating from further distances above less distant origin layers are discussed [fr

  9. Applicability of a numerical model to predict vertical distribution of suspended sediment concentration along the depth in Dithmarschen Bight

    Science.gov (United States)

    Rahbani, M.

    2012-04-01

    A three dimensional numerical model of Delft3d-flow was developed to simulate the current velocity and sediment transport of Piep tidal channel system. This channel system is part of Dithmarschen Bight located in the German North Sea coast. It consists of two main channel namely Norderpiep, and Süderpiep. These two channels conjunct together to form Piep channel near the land on tidal flat. The source of the required field data for this study was those collected under "Prediction of Medium Term Coastal Morphodynamics", known as the PROMORPH project. It was executed during the period May 1999 to June 2002. Those measured data used for calibration and validation of the model were current velocity and suspended sediment concentration (SSC). Current velocities were collected using ADCP devise. Suspended sediment concentration data was prepared by converting the measured values of light transmission. These data was collected using transmissometer. On the basis of some in situ mechanical sampler data an equation was developed to convert light transmission to the SSC. Field data were carried out at several stations along the width of three cross sections from the surface to the bottom, taking into account the limitations. To verify the performance of the calibrated model, its results were compared with the field data. The comparison between the modeled and measured current velocity shows an accuracy of about 0.2 m/s. Factor of two of measured SSC were used to evaluate the performance of the model regarding these values. Some dissimilarity was found between the modeled SSC and those of the field data.To verify the cause of this dissimilarity, two comparing procedures were carried out. First the evolution of the vertical profile of the SSC from the model and those from the field were prepared and compared. In another procedure the snapshot of distribution of SSC at each cross section during different phases of a tidal cycle were prepared using the model results and

  10. Comparison of depth-dose distributions of proton therapeutic beams calculated by means of logical detectors and ionization chamber modeled in Monte Carlo codes

    Energy Technology Data Exchange (ETDEWEB)

    Pietrzak, Robert [Department of Nuclear Physics and Its Applications, Institute of Physics, University of Silesia, Katowice (Poland); Konefał, Adam, E-mail: adam.konefal@us.edu.pl [Department of Nuclear Physics and Its Applications, Institute of Physics, University of Silesia, Katowice (Poland); Sokół, Maria; Orlef, Andrzej [Department of Medical Physics, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Gliwice (Poland)

    2016-08-01

    The success of proton therapy depends strongly on the precision of treatment planning. Dose distribution in biological tissue may be obtained from Monte Carlo simulations using various scientific codes making it possible to perform very accurate calculations. However, there are many factors affecting the accuracy of modeling. One of them is a structure of objects called bins registering a dose. In this work the influence of bin structure on the dose distributions was examined. The MCNPX code calculations of Bragg curve for the 60 MeV proton beam were done in two ways: using simple logical detectors being the volumes determined in water, and using a precise model of ionization chamber used in clinical dosimetry. The results of the simulations were verified experimentally in the water phantom with Marcus ionization chamber. The average local dose difference between the measured relative doses in the water phantom and those calculated by means of the logical detectors was 1.4% at first 25 mm, whereas in the full depth range this difference was 1.6% for the maximum uncertainty in the calculations less than 2.4% and for the maximum measuring error of 1%. In case of the relative doses calculated with the use of the ionization chamber model this average difference was somewhat greater, being 2.3% at depths up to 25 mm and 2.4% in the full range of depths for the maximum uncertainty in the calculations of 3%. In the dose calculations the ionization chamber model does not offer any additional advantages over the logical detectors. The results provided by both models are similar and in good agreement with the measurements, however, the logical detector approach is a more time-effective method. - Highlights: • Influence of the bin structure on the proton dose distributions was examined for the MC simulations. • The considered relative proton dose distributions in water correspond to the clinical application. • MC simulations performed with the logical detectors and the

  11. The Global Terrestrial Network for Permafrost Database: metadata statistics and prospective analysis on future permafrost temperature and active layer depth monitoring site distribution

    Science.gov (United States)

    Biskaborn, B. K.; Lanckman, J.-P.; Lantuit, H.; Elger, K.; Streletskiy, D. A.; Cable, W. L.; Romanovsky, V. E.

    2015-03-01

    The Global Terrestrial Network for Permafrost (GTN-P) provides the first dynamic database associated with the Thermal State of Permafrost (TSP) and the Circumpolar Active Layer Monitoring (CALM) programs, which extensively collect permafrost temperature and active layer thickness data from Arctic, Antarctic and Mountain permafrost regions. The purpose of the database is to establish an "early warning system" for the consequences of climate change in permafrost regions and to provide standardized thermal permafrost data to global models. In this paper we perform statistical analysis of the GTN-P metadata aiming to identify the spatial gaps in the GTN-P site distribution in relation to climate-effective environmental parameters. We describe the concept and structure of the Data Management System in regard to user operability, data transfer and data policy. We outline data sources and data processing including quality control strategies. Assessment of the metadata and data quality reveals 63% metadata completeness at active layer sites and 50% metadata completeness for boreholes. Voronoi Tessellation Analysis on the spatial sample distribution of boreholes and active layer measurement sites quantifies the distribution inhomogeneity and provides potential locations of additional permafrost research sites to improve the representativeness of thermal monitoring across areas underlain by permafrost. The depth distribution of the boreholes reveals that 73% are shallower than 25 m and 27% are deeper, reaching a maximum of 1 km depth. Comparison of the GTN-P site distribution with permafrost zones, soil organic carbon contents and vegetation types exhibits different local to regional monitoring situations on maps. Preferential slope orientation at the sites most likely causes a bias in the temperature monitoring and should be taken into account when using the data for global models. The distribution of GTN-P sites within zones of projected temperature change show a high

  12. Catalytic processing of high-sulfur fuels for distributed hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Muradov, Nazim; Ramasamy, Karthik; Huang, Cunping; T-Raissi, Ali [Central Florida Univ., FL (United States)

    2010-07-01

    In this work, the development of a new on-demand hydrogen production technology is reported. In this process, a liquid hydrocarbon fuel (e.g., high-S diesel) is first catalytically pre-reformed to shorter chain gaseous hydrocarbons (predominantly, C{sub 1}-C{sub 3}) before being directed to the steam reformer, where it is converted to syngas and then to high-purity hydrogen. In the pre-reformer, most sulfurous species present in the fuel are catalytically converted to H{sub 2}S. In the desulfurization unit, H{sub 2}S is scrubbed and converted to H{sub 2} and elemental sulfur. Desulfurization of the pre-reformate gas is carried out in a special regenerative redox system, which includes Fe(II)/Fe(III)-containing aqueous phase scrubber coupled with an electrolyzer. The integrated pre-reformer/scrubber/electrolyzer unit operated successfully on high-S diesel fuel for more than 100 hours meeting the required desulfurization target of >95 % sulfur removal. (orig.)

  13. The hydrogen; L'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

  14. Hawaii hydrogen energy economy: production and distribution of hydrogen and oxygen in the district of north Kohala, the Big Island of Hawaii: a global prototype

    International Nuclear Information System (INIS)

    Russel, G.

    1993-01-01

    This paper shows how a community which is totally oil dependent can be transformed into a hydrogen fuel based economy by using the concept of setting hydrogen zones, with the use of off-peak hydro-electrical power and renewable energies. An existing hydro-electric plant in Hawaii could serve as a local prototype. 2 figs

  15. Temperature profile and water depth data collected from SAXON STAR and other platforms in a World wide distribution from 09 March 1983 to 12 November 1986 (NODC Accession 8700035)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the SAXON STAR and other platforms in a World wide distribution. Data were collected...

  16. In-depth characterization of the fluorescent signal of HyPer, a probe for hydrogen peroxide, in bacteria exposed to external oxidative stress.

    Science.gov (United States)

    Lim, Joseph B; Barker, Kimberly A; Huang, Beijing K; Sikes, Hadley D

    2014-11-01

    Genetically encoded, fluorescent biosensors have been developed to probe the activities of various signaling molecules inside cells ranging from changes in intracellular ion concentrations to dynamics of lipid second messengers. HyPer is a member of this class of biosensors and is the first to dynamically respond to hydrogen peroxide (H2O2), a reactive oxygen species that functions as a signaling molecule. However, detailed characterization of HyPer's signal is not currently available within the context of bacteria exposed to external oxidative stress, which occurs in the immunological response of higher organisms against invasive pathogenic bacteria. Here, we performed this characterization, specifically in Escherichia coli exposed to external H2O2. We found that the temporal behavior of the signal does not correspond exactly to peroxide concentration in the system as a function of time and expression of the sensor decreases the peroxide scavenging activity of the cell. We also determined the effects of cell number, both before and after normalization of externally added H2O2 to the number of cells. Finally, we report quantitative characteristics of HyPer's signal in this context, including the dynamic range of the signal, the signal-to-noise ratio, and the half saturation constant. These parameters show statistically meaningful differences in signal between two commonly used strains of E. coli, demonstrating how signal can vary with strain. Taken together, our results establish a systematic, quantitative framework for researchers seeking to better understand the role of H2O2 in the immunological response against bacteria, and for understanding potential differences in the details of HyPer's quantitative performance across studies. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. A simulation study of Linsley's approach to infer elongation rate and fluctuations of the EAS maximum depth from muon arrival time distributions

    International Nuclear Information System (INIS)

    Badea, A.F.; Brancus, I.M.; Rebel, H.; Haungs, A.; Oehlschlaeger, J.; Zazyan, M.

    1999-01-01

    The average depth of the maximum X m of the EAS (Extensive Air Shower) development depends on the energy E 0 and the mass of the primary particle, and its dependence from the energy is traditionally expressed by the so-called elongation rate D e defined as change in the average depth of the maximum per decade of E 0 i.e. D e = dX m /dlog 10 E 0 . Invoking the superposition model approximation i.e. assuming that a heavy primary (A) has the same shower elongation rate like a proton, but scaled with energies E 0 /A, one can write X m = X init + D e log 10 (E 0 /A). In 1977 an indirect approach studying D e has been suggested by Linsley. This approach can be applied to shower parameters which do not depend explicitly on the energy of the primary particle, but do depend on the depth of observation X and on the depth X m of shower maximum. The distribution of the EAS muon arrival times, measured at a certain observation level relatively to the arrival time of the shower core reflect the pathlength distribution of the muon travel from locus of production (near the axis) to the observation locus. The basic a priori assumption is that we can associate the mean value or median T of the time distribution to the height of the EAS maximum X m , and that we can express T = f(X,X m ). In order to derive from the energy variation of the arrival time quantities information about elongation rate, some knowledge is required about F i.e. F = - ∂ T/∂X m ) X /∂(T/∂X) X m , in addition to the variations with the depth of observation and the zenith-angle (θ) dependence, respectively. Thus ∂T/∂log 10 E 0 | X = - F·D e ·1/X v ·∂T/∂secθ| E 0 . In a similar way the fluctuations σ(X m ) of X m may be related to the fluctuations σ(T) of T i.e. σ(T) = - σ(X m )· F σ ·1/X v ·∂T/∂secθ| E 0 , with F σ being the corresponding scaling factor for the fluctuation of F. By simulations of the EAS development using the Monte Carlo code CORSIKA the energy and angle

  18. The impact of aerosol vertical distribution on aerosol optical depth retrieval using CALIPSO and MODIS data: Case study over dust and smoke regions

    Science.gov (United States)

    Wu, Yerong; de Graaf, Martin; Menenti, Massimo

    2017-08-01

    Global quantitative aerosol information has been derived from MODerate Resolution Imaging SpectroRadiometer (MODIS) observations for decades since early 2000 and widely used for air quality and climate change research. However, the operational MODIS Aerosol Optical Depth (AOD) products Collection 6 (C6) can still be biased, because of uncertainty in assumed aerosol optical properties and aerosol vertical distribution. This study investigates the impact of aerosol vertical distribution on the AOD retrieval. We developed a new algorithm by considering dynamic vertical profiles, which is an adaptation of MODIS C6 Dark Target (C6_DT) algorithm over land. The new algorithm makes use of the aerosol vertical profile extracted from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) measurements to generate an accurate top of the atmosphere (TOA) reflectance for the AOD retrieval, where the profile is assumed to be a single layer and represented as a Gaussian function with the mean height as single variable. To test the impact, a comparison was made between MODIS DT and Aerosol Robotic Network (AERONET) AOD, over dust and smoke regions. The results show that the aerosol vertical distribution has a strong impact on the AOD retrieval. The assumed aerosol layers close to the ground can negatively bias the retrievals in C6_DT. Regarding the evaluated smoke and dust layers, the new algorithm can improve the retrieval by reducing the negative biases by 3-5%.

  19. Distribution of hydrogen within the HDR-containment under severe accident conditions. OECD standard problem. Final comparison report

    International Nuclear Information System (INIS)

    Karwat, H.

    1992-08-01

    The present report summarizes the results of the International Standard Problem Exercise ISP-29, based on the HDR Hydrogen Distribution Experiment E11.2. Post-test analyses are compared to experimentally measured parameters, well-known to the analysis. This report has been prepared by the Institute for Reactor Dynamics and Reactor Safety of the Technical University Munich under contract with the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) which received funding for this activity from the German Ministry for Research and Technology (BMFT) under the research contract RS 792. The HDR experiment E11.2 has been performed by the Kernforschungszentrum Karlsruhe (KfK) in the frame of the project 'Projekt HDR-Sicherheitsprogramm' sponsored by the BMFT. Ten institutions from eight countries participated in the post-test analysis exercise which was focussing on the long-lasting gas distribution processes expected inside a PWR containment under severe accident conditions. The gas release experiment was coupled to a long-lasting steam release into the containment typical for an unmitigated small break loss-of-coolant accident. In lieu of pure hydrogen a gas mixture consisting of 15% hydrogen and 85% helium has been applied in order to avoid reaching flammability during the experiment. Of central importance are common overlay plots comparing calculated transients with measurements of the global pressure, the local temperature-, steam- and gas concentration distributions throughout the entire HDR containment. The comparisons indicate relatively large margins between most calculations and the experiment. Having in mind that this exercise was specified as an 'open post-test' analysis of well-known measured data the reasons for discrepancies between measurements and simulations were extensively discussed during a final workshop. It was concluded that analytical shortcomings as well as some uncertainties of experimental boundary conditions may be responsible for deviations

  20. Distribution of hydrogen within the HDR-containment under severe accident conditions. OECD standard problem. Final comparison report

    Energy Technology Data Exchange (ETDEWEB)

    Karwat, H

    1992-08-15

    The present report summarizes the results of the International Standard Problem Exercise ISP-29, based on the HDR Hydrogen Distribution Experiment E11.2. Post-test analyses are compared to experimentally measured parameters, well-known to the analysis. This report has been prepared by the Institute for Reactor Dynamics and Reactor Safety of the Technical University Munich under contract with the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) which received funding for this activity from the German Ministry for Research and Technology (BMFT) under the research contract RS 792. The HDR experiment E11.2 has been performed by the Kernforschungszentrum Karlsruhe (KfK) in the frame of the project 'Projekt HDR-Sicherheitsprogramm' sponsored by the BMFT. Ten institutions from eight countries participated in the post-test analysis exercise which was focussing on the long-lasting gas distribution processes expected inside a PWR containment under severe accident conditions. The gas release experiment was coupled to a long-lasting steam release into the containment typical for an unmitigated small break loss-of-coolant accident. In lieu of pure hydrogen a gas mixture consisting of 15% hydrogen and 85% helium has been applied in order to avoid reaching flammability during the experiment. Of central importance are common overlay plots comparing calculated transients with measurements of the global pressure, the local temperature-, steam- and gas concentration distributions throughout the entire HDR containment. The comparisons indicate relatively large margins between most calculations and the experiment. Having in mind that this exercise was specified as an 'open post-test' analysis of well-known measured data the reasons for discrepancies between measurements and simulations were extensively discussed during a final workshop. It was concluded that analytical shortcomings as well as some uncertainties of experimental boundary conditions may be responsible for deviations

  1. Zooxanthellae of the Montastraea annularis species complex: patterns of distribution of four taxa of Symbiodinium on different reefs and across depths.

    Science.gov (United States)

    Toller, W W; Rowan, R; Knowlton, N

    2001-12-01

    Corals of the Montastraea annularis complex host several different dinoflagellates in the genus Symbiodinium. Here we address two questions arising from our previous studies of these associations on an offshore reef. First, do the same taxa and patterns of association (Symbiodinium A and B found in higher irradiance habitats than Symbiodinium C) occur on an inshore reef? Second, does M. franksi at the limits of its depth range host only Symbiodinium C, as it does at intermediate depths? In both surveys, a new Symbiodinium taxon and different patterns of distribution (assayed by analyses of small ribosomal subunit RNA genes [srDNA]) were observed. Inshore, a taxon we name Symbiodinium E predominated in higher irradiance habitats in M. franksi and its two sibling species; the only other zooxanthella observed was Symbiodinium C. Offshore, M. franksi mainly hosted Symbiodinium C, but hosted Symbiodinium A, B, C, and E in shallow water and Symbiodinium E and C in very deep water. Symbiodinium E may be stress-tolerant. Observed srDNA heterogeneity within samples of Symbiodinium B, C, and E is interpreted as variation across copies within this multigene family. Experimental bleaching of Symbiodinium C supported this interpretation. Thus sequences from natural samples should be interpreted cautiously.

  2. RBS and ERDA determinations of depth distributions of high-dose carbon ions implanted in silicon for silicon-carbide synthesis study

    International Nuclear Information System (INIS)

    Intarasiri, S.; Kamwanna, T.; Hallen, A.; Yu, L.D.; Janson, M.S.; Thongleum, C.; Possnert, G.; Singkarat, S.

    2006-01-01

    For ion beam synthesis of silicon carbide (SiC), a knowledge of the depth distribution of implanted carbon ions in silicon is crucial for successful development. Based on its simplicity and availability, we selected Rutherford backscattering spectrometry (RBS) as an analysis technique for this purpose. A self-developed computer program dedicated to extract depth profiles of lighter impurities in heavier matrix is established. For control, calculated results are compared with an other ion beam analysis (IBA) technique superior for studying lighter impurity in heavier substrate i.e. elastic recoil detection analysis (ERDA). The RBS was performed with a 1.7-MV Tandetron accelerator using He 2+ as the probe ions. The ERDA was performed with a 5-MV Pelletron accelerator using I 8+ as the probe ions. This work shows that the RBS-extracted data had no significant deviations from those of ERDA and simulations by SRIM2003 and SIIMPL computer codes. We also found that annealing at temperatures as high as 1000 deg. C had quite limited effect on the redistribution of carbon in silicon

  3. Monte Carlo simulation of electron depth distribution and backscattering for carbon films deposited on aluminium as a function of incidence angle and primary energy

    Science.gov (United States)

    Dapor, Maurizio

    2005-01-01

    Carbon films are deposited on various substrates (polymers, polyester fabrics, polyester yarns, metal alloys) both for experimental and technological motivations (medical devices, biocompatible coatings, food package and so on). Computational studies of the penetration of electron beams in supported thin film of carbon are very useful in order to compare the simulated results with analytical techniques data (obtained by scanning electron microscopy and/or Auger electron spectroscopy) and investigate the film characteristics. In the present paper, the few keV electron depth distribution and backscattering coefficient for the special case of film of carbon deposited on aluminium are investigated, by a Monte Carlo simulation, as a function of the incidence angle and primary electron energy. The simulated results can be used as a way to evaluate the carbon film thickness by a set of measurements of the backscattering coefficient.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Effect of Grain Orientation and Boundary Distributions on Hydrogen-Induced Cracking in Low-Carbon-Content Steels

    Science.gov (United States)

    Masoumi, Mohammad; Coelho, Hana Livia Frota; Tavares, Sérgio Souto Maior; Silva, Cleiton Carvalho; de Abreu, Hamilton Ferreira Gomes

    2017-08-01

    Hydrogen-induced cracking (HIC) causes considerable economic losses in a wide range of steels exposed to corrosive environments. The effect of crystallographic texture and grain boundary distributions tailored by rolling at 850 °C in three different steels with a body-centered cube structure was investigated on HIC resistance. The x-ray and electron backscattered diffraction techniques were used to characterize texture evolutions during the rolling process. The findings revealed a significant improvement against HIC based on texture engineering. In addition, increasing the number of {111} and {110} grains, associated with minimizing the number of {001} grains in warm-rolled samples, reduced HIC susceptibility. Moreover, the results showed that boundaries associated with low {hkl} indexing and denser packing planes had more resistance against crack propagation.

  6. Echinoid associations with coral habitats differ with taxon in the deep sea and the influence of other echinoids, depth, and fishing history on their distribution

    Science.gov (United States)

    Stevenson, Angela; Davies, Jaime S.; Williams, Alan; Althaus, Franziska; Rowden, Ashley A.; Bowden, David A.; Clark, Malcolm R.; Mitchell, Fraser J. G.

    2018-03-01

    Patterns of habitat use by animals and knowledge of the environmental factors affecting these spatial patterns are important for understanding the structure and dynamics of ecological communities. Both aspects are poorly known for deep-sea habitats. The present study investigates echinoid distributions within cold water coral (CWC) habitats on continental margins off France, Australia, and New Zealand. It further examines the influence of habitat-related variables that might help explain the observed distribution of echinoid taxa. Six echinoid taxa were examined from video and photographic transects to reveal taxon-specific distribution patterns and habitat-related influences. The Echinoidea were found in all habitats studied, but tended to aggregate in architecturally complex habitats associated with living cold-water corals. However, a taxon-specific investigation found that such associations were largely an artefact of the dominant taxa observed in a specific region. Despite the food and shelter resources offered to echinoids by matrix-forming coral habitats, not all taxa were associated with these habitats, and some had a random association with the habitats examined, while others displayed non-random associations. Echinoid distribution was correlated with several variables; the presence of other echinoids, depth, and fishing history were the most influential factors. This study indicates that image data can be a useful tool to detect trends in echinoid habitat associations. It also suggests that refinement of the methods, in particular with studies conducted at a more precise taxon and habitat scale, would facilitate better quantitative analyses of habitat associations and paint a more realistic picture of a population's ecology. Most deep-sea ecological studies to date have been conducted at a relatively coarse taxonomic and habitat resolution, and lack sufficient resolution to provide useful information for the conservation of vulnerable deep-sea habitats.

  7. Large scale experiments simulating hydrogen distribution in a spent fuel pool building during a hypothetical fuel uncovery accident scenario

    Energy Technology Data Exchange (ETDEWEB)

    Mignot, Guillaume; Paranjape, Sidharth; Paladino, Domenico; Jaeckel, Bernd; Rydl, Adolf [Paul Scherrer Institute, Villigen (Switzerland)

    2016-08-15

    Following the Fukushima accident and its extended station blackout, attention was brought to the importance of the spent fuel pools' (SFPs) behavior in case of a prolonged loss of the cooling system. Since then, many analytical works have been performed to estimate the timing of hypothetical fuel uncovery for various SFP types. Experimentally, however, little was done to investigate issues related to the formation of a flammable gas mixture, distribution, and stratification in the SFP building itself and to some extent assess the capability for the code to correctly predict it. This paper presents the main outcomes of the Experiments on Spent Fuel Pool (ESFP) project carried out under the auspices of Swissnuclear (Framework 2012–2013) in the PANDA facility at the Paul Scherrer Institut in Switzerland. It consists of an experimental investigation focused on hydrogen concentration build-up into a SFP building during a predefined scaled scenario for different venting positions. Tests follow a two-phase scenario. Initially steam is released to mimic the boiling of the pool followed by a helium/steam mixture release to simulate the deterioration of the oxidizing spent fuel. Results shows that while the SFP building would mainly be inerted by the presence of a high concentration of steam, the volume located below the level of the pool in adjacent rooms would maintain a high air content. The interface of the two-gas mixture presents the highest risk of flammability. Additionally, it was observed that the gas mixture could become stagnant leading locally to high hydrogen concentration while steam condenses. Overall, the experiments provide relevant information for the potentially hazardous gas distribution formed in the SFP building and hints on accident management and on eventual retrofitting measures to be implemented in the SFP building.

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  9. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

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

  10. Detailed modeling of size distribution functions and hydrogen content in combustion-formed particles

    Energy Technology Data Exchange (ETDEWEB)

    Sirignano, Mariano; D' Anna, Andrea [Dipartimento di Ingegneria Chimica, Universita di Napoli ' ' Federico II' ' , Napoli (Italy); Kent, John [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney (Australia)

    2010-06-15

    A kinetic modeling approach is proposed to delve into the nature and chemistry of combustion-produced particles. A sectional method is used for the first time on this purpose. It is based on modeling of gas-to-particle transitions by sections containing 125 lumped species with C numbers ranging from 24 to 4 x 10{sup 8} and H/C ratio ranging from 0 to 1. This allows not only the mass evolution of particles, but also their hydrogen content to be followed. The model is tested in an atmospheric pressure premixed flat flame of ethylene/oxygen with C/O = 0.8 and cold gas flow velocity of 4 cm/s. Comparison of modeled results with experimental data is satisfying in terms of species concentrations and H/C ratio of the particles. Analysis of model results in comparison with the experimental data has shown that it is possible to distinguish different precursors of particles moving from the exit of the burner into the post-oxidation region of the flame. At particle inception, i.e. just downstream from the flame front, gas-phase PAHs are responsible for particle nucleation and oligomers of aromatic hydrocarbons and small pericondensed hydrocarbons are predominantly present. Then the dehydrogenation process takes place and soot formation starts; in this zone large pericondensed and stacked structures are produced. Further up soot maturation generally linked with dehydrogenation is present, but still a few particles with higher H/C and with low coagulation efficiency are produced and remain present along the flame. The model, in accordance with experimental structural soot analysis, shows that in soot particles condensed structures typical of clusters of large pericondensed hydrocarbons are present whereas high-molecular mass condensed species mainly comprise oligomers of small aromatic compounds of clusters of small pericondensed hydrocarbons. (author)

  11. Pore size distribution and supercritical hydrogen adsorption in activated carbon fibers

    Science.gov (United States)

    Purewal, J. J.; Kabbour, H.; Vajo, J. J.; Ahn, C. C.; Fultz, B.

    2009-05-01

    Pore size distributions (PSD) and supercritical H2 isotherms have been measured for two activated carbon fiber (ACF) samples. The surface area and the PSD both depend on the degree of activation to which the ACF has been exposed. The low-surface-area ACF has a narrow PSD centered at 0.5 nm, while the high-surface-area ACF has a broad distribution of pore widths between 0.5 and 2 nm. The H2 adsorption enthalpy in the zero-coverage limit depends on the relative abundance of the smallest pores relative to the larger pores. Measurements of the H2 isosteric adsorption enthalpy indicate the presence of energy heterogeneity in both ACF samples. Additional measurements on a microporous, coconut-derived activated carbon are presented for reference.

  12. Pore size distribution and supercritical hydrogen adsorption in activated carbon fibers

    International Nuclear Information System (INIS)

    Purewal, J J; Kabbour, H; Ahn, C C; Fultz, B; Vajo, J J

    2009-01-01

    Pore size distributions (PSD) and supercritical H 2 isotherms have been measured for two activated carbon fiber (ACF) samples. The surface area and the PSD both depend on the degree of activation to which the ACF has been exposed. The low-surface-area ACF has a narrow PSD centered at 0.5 nm, while the high-surface-area ACF has a broad distribution of pore widths between 0.5 and 2 nm. The H 2 adsorption enthalpy in the zero-coverage limit depends on the relative abundance of the smallest pores relative to the larger pores. Measurements of the H 2 isosteric adsorption enthalpy indicate the presence of energy heterogeneity in both ACF samples. Additional measurements on a microporous, coconut-derived activated carbon are presented for reference.

  13. Distribution of energetic oxygen and hydrogen in the near-Earth plasma sheet

    Science.gov (United States)

    Kronberg, E. A.; Grigorenko, E. E.; Haaland, S. E.; Daly, P. W.; Delcourt, D. C.; Luo, H.; Kistler, L. M.; Dandouras, I.

    2015-05-01

    The spatial distributions of different ion species are useful indicators for plasma sheet dynamics. In this statistical study based on 7 years of Cluster observations, we establish the spatial distributions of oxygen ions and protons at energies from 274 to 955 keV, depending on geomagnetic and solar wind (SW) conditions. Compared with protons, the distribution of energetic oxygen has stronger dawn-dusk asymmetry in response to changes in the geomagnetic activity. When the interplanetary magnetic field (IMF) is directed southward, the oxygen ions show significant acceleration in the tail plasma sheet. Changes in the SW dynamic pressure (Pdyn) affect the oxygen and proton intensities in the same way. The energetic protons show significant intensity increases at the near-Earth duskside during disturbed geomagnetic conditions, enhanced SW Pdyn, and southward IMF, implying there location of effective inductive acceleration mechanisms and a strong duskward drift due to the increase of the magnetic field gradient in the near-Earth tail. Higher losses of energetic ions are observed in the dayside plasma sheet under disturbed geomagnetic conditions and enhanced SW Pdyn. These observations are in agreement with theoretical models.

  14. Final comparison report on ISP-35: Nupec hydrogen mixing and distribution test (Test M-7-1)

    International Nuclear Information System (INIS)

    1994-12-01

    This final comparison report summarizes the results of the OECD/CSNI sponsored ISP-35 exercise which was based on NUPEC's Hydrogen Mixing and Distribution Test M-7-1. 12 organizations from 10 different countries took part in the exercise. For the ISP-35 test, a steam/light gas (helium) mixture was released into the lower region of a simplified model of a PWR containment. At the same time, the dome cooling spray was also activated. the transient time histories for gas temperature and concentrations were recorded for each of the 25 compartments of the model containment. The wall temperatures as well as the dome pressure were also recorded. The ISP-35 participants simulated the test conditions and attempted to predict the time histories using their accident analysis codes. Results of these analyses are presented, and comparisons are made between the experimental data and the calculated data. In general, predictions for pressure, helium concentration and gas distribution patterns were achieved with acceptable accuracy

  15. Vicinage forces between molecular and atomic fragments dissociated from small hydrogen clusters and their effects on energy distributions

    International Nuclear Information System (INIS)

    Barriga-Carrasco, Manuel D.; Garcia-Molina, Rafael

    2003-01-01

    In this paper we analyze the dynamic evolution of molecular and atomic fragments of small hydrogen clusters interacting with thin solid foils. We compare the vicinage forces, calculated within the dielectric formalism, for H + , H 0 , and H 2 + fragments. Using a molecular dynamics numerical code we determine the energy distribution of the fragments after interacting with the target. This distribution is compared to experimental results for protons coming from the fragmentation of v=2.02 a.u. H 2 + ions impinging on an aluminum foil; a fraction of neutral H 0 is needed to be included in the simulation to get a good agreement with the experimental results. The H 2 + energy spectra for v=5.42 a.u. H 3 + interacting with amorphous carbon is also determined. The asymmetry in the Coulomb peaks appearing in the energy spectra both experimentally and in our calculation is opposite for H 2 + than in H + ; kinematic effects and differences in the electronic stopping are enough to reproduce the difference in the alignment of H 2 + and H + fragments

  16. The study of a hydrological model and its parameters using data on the distribution of hydrogen isotopes

    International Nuclear Information System (INIS)

    Miyamoto, Kiriko

    1996-01-01

    This work focuses on the hydrogen isotopic study of water for the purpose of improving environmental transfer models and parameters with regard to radionuclides. Fallout tritium and the natural deuterium in environmental water were used as natural tracers to investigate the local terrestrial hydrological cycle in Rokkasho Village. From 1991, samples of groundwater, river water and lake/pond water were collected in the village. Their tritium and deuterium content were determined. Groundwater samples can be divided into three groups on the basis of their tritium level and the depth of the layer that they originate from, vis. Group A; samples in the range 0.5-1.1 Bq/l originated from the shallowest layer. Group B; samples in the range 1.5-2.7 Bq/l from a deeper layer. Group C; samples below 0.1 Bq/l from the deepest layer. The river and the lake/pond water were defined as the combined runoff water from the three groundwater reservoir layers, according to their tritium concentrations. A calculational model derived for the Kanto Plain was applied to Rokkasho Village. The tritium concentration for the river water in Rokkasho Village was well simulated by application of the model, if both of the following assumptions are applied. One is that the input of tritium into the area by precipitation is 1.5 times that in the Kanto Plain for 1954-1995. The other is that the size of the Group B groundwater reservoir is one third of that for the Kanto Plain. The well-known altitude effect and the distance effect from the sea as well as the local climatological effect on the deuterium fractionation of the meteoric water were demonstrated in a NE-SW direction in the village. A large amount of Group B groundwater flows out in a SW direction in the village. Hydrogen isotopic studies were found to be indispensable for the improvement of environmental transfer models and parameters related to radionuclides. (author)

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  18. Hydrogen calibration of GD-spectrometer using Zr-1Nb alloy

    Science.gov (United States)

    Mikhaylov, Andrey A.; Priamushko, Tatiana S.; Babikhina, Maria N.; Kudiiarov, Victor N.; Heller, Rene; Laptev, Roman S.; Lider, Andrey M.

    2018-02-01

    To study the hydrogen distribution in Zr-1Nb alloy (Э110 alloy) GD-OES was applied in this work. Qualitative analysis needs the standard samples with hydrogen. However, the standard samples with high concentrations of hydrogen in the zirconium alloy which would meet the requirements of the shape, size are absent. In this work method of Zr + H calibration samples production was performed at the first time. Automated Complex Gas Reaction Controller was used for samples hydrogenation. To calculate the parameters of post-hydrogenation incubation of the samples in an inert gas atmosphere the diffusion equations were used. Absolute hydrogen concentrations in the samples were determined by melting in the inert gas atmosphere using RHEN602 analyzer (LECO Company). Hydrogen distribution was studied using nuclear reaction analysis (HZDR, Dresden, Germany). RF GD-OES was used for calibration. The depth of the craters was measured with the help of a Hommel-Etamic profilometer by Jenoptik, Germany.

  19. Root Systems of Individual Plants, and the Biotic and Abiotic Factors Controlling Their Depth and Distribution: a Synthesis Using a Global Database.

    Science.gov (United States)

    Tumber-Davila, S. J.; Schenk, H. J.; Jackson, R. B.

    2017-12-01

    This synthesis examines plant rooting distributions globally, by doubling the number of entries in the Root Systems of Individual Plants database (RSIP) created by Schenk and Jackson. Root systems influence many processes, including water and nutrient uptake and soil carbon storage. Root systems also mediate vegetation responses to changing climatic and environmental conditions. Therefore, a collective understanding of the importance of rooting systems to carbon sequestration, soil characteristics, hydrology, and climate, is needed. Current global models are limited by a poor understanding of the mechanisms affecting rooting, carbon stocks, and belowground biomass. This improved database contains an extensive bank of records describing the rooting system of individual plants, as well as detailed information on the climate and environment from which the observations are made. The expanded RSIP database will: 1) increase our understanding of rooting depths, lateral root spreads and above and belowground allometry; 2) improve the representation of plant rooting systems in Earth System Models; 3) enable studies of how climate change will alter and interact with plant species and functional groups in the future. We further focus on how plant rooting behavior responds to variations in climate and the environment, and create a model that can predict rooting behavior given a set of environmental conditions. Preliminary results suggest that high potential evapotranspiration and seasonality of precipitation are indicative of deeper rooting after accounting for plant growth form. When mapping predicted deep rooting by climate, we predict deepest rooting to occur in equatorial South America, Africa, and central India.

  20. Impact of He and H relative depth distributions on the result of sequential He+ and H+ ion implantation and annealing in silicon

    Science.gov (United States)

    Cherkashin, N.; Daghbouj, N.; Seine, G.; Claverie, A.

    2018-04-01

    Sequential He++H+ ion implantation, being more effective than the sole implantation of H+ or He+, is used by many to transfer thin layers of silicon onto different substrates. However, due to the poor understanding of the basic mechanisms involved in such a process, the implantation parameters to be used for the efficient delamination of a superficial layer are still subject to debate. In this work, by using various experimental techniques, we have studied the influence of the He and H relative depth-distributions imposed by the ion energies onto the result of the sequential implantation and annealing of the same fluence of He and H ions. Analyzing the characteristics of the blister populations observed after annealing and deducing the composition of the gas they contain from FEM simulations, we show that the trapping efficiency of He atoms in platelets and blisters during annealing depends on the behavior of the vacancies generated by the two implants within the H-rich region before and after annealing. Maximum efficiency of the sequential ion implantation is obtained when the H-rich region is able to trap all implanted He ions, while the vacancies it generated are not available to favor the formation of V-rich complexes after implantation then He-filled nano-bubbles after annealing. A technological option is to implant He+ ions first at such an energy that the damage it generates is located on the deeper side of the H profile.

  1. Using geographic distribution of well-screen depths and hydrogeologic conditions to identify areas of concern for contaminant migration through inactive supply wells

    Science.gov (United States)

    Gailey, Robert M.

    2018-02-01

    Contaminant migration through inactive supply wells can negatively affect groundwater quality and the combined effects from groups of such wells may cause greater impacts. Because the number of wells in many basins is often large and the geographic areas involved can be vast, approaches are needed to estimate potential impacts and focus limited resources for investigation and corrective measures on the most important areas. One possibility is to evaluate the geographic distribution of well-screen depths relative to hydrogeologic conditions and assess where contaminant migration through wells may be impacting groundwater quality. This approach is demonstrated for a geographically extensive area in the southern Central Valley of California, USA. The conditions that lead to wells acting as conduits for contaminant migration are evaluated and areas where the problem likely occurs are identified. Although only a small fraction of all wells appear to act as conduits, potential impacts may be significant considering needs to control nonpoint-source pollution and improve drinking water quality for rural residents. Addressing a limited number of areas where contaminant migration rates are expected to be high may cost-effectively accomplish the most beneficial groundwater quality protection and improvement. While this work focuses on a specific region, the results indicate that impacts from groups of wells may occur in other areas with similar conditions. Analyses similar to that demonstrated here may guide efficient investigation and corrective action in such areas with benefits occurring for groundwater quality. Potential benefits may justify expenditures to develop the necessary data for performing the analyses.

  2. Organic matter in primitive meteorites: a study of the hydrogen isotopic distribution in CM-type carbonaceous chondrites

    Science.gov (United States)

    Piani, L.; Yurimoto, H.; Remusat, L.; Gonzales, A.; Marty, B.

    2017-12-01

    Chondrite meteorites are fragments of rocks coming from small bodies of the asteroid belt and constitute witnesses of the volatile-rich reservoirs present in the inner protoplanetary disk. Among these meteorites, carbonaceous chondrites contain the largest quantity of water and organic matter and are one of the most probable candidates for the delivery of water and molecular origin of life to Earth. Organic matter in carbonaceous chondrites is intimately mixed with hydrated minerals challenging its in situ characterization and the determination of its H-isotope composition (Le Guillou et al., GCA 131, 2014). Organic matter occurs as soluble components (in water or organic solvents) and an insoluble macromolecule. The insoluble organic matter (IOM) is efficiently isolated after acid leaching of the chondrite minerals. IOM has thus been investigated by a large set of analytical techniques allowing its structural organization, chemical composition and isotopic composition to be determined at several scales (e.g. Derenne and Robert, MAPS 45, 2010). In the soluble counterpart (SOM), targeted studies have shown large ranges of D/H ratios in the different classes of soluble organic compounds (i.e. carboxylic acids, ketones and aldehydes, amino-acids etc.) (Remusat, Planetary Mineralogy 15, 2015 and references therein). This D/H distribution indicates a complex and probably multiple-stage synthesis of this organic compounds occurring at different stages of the disk evolution. Nevertheless, inventories of the known C-bearing species in carbonaceous chondrites (carbonates, SOM and IOM) show that about 40-50 % of the carbon is hidden within the matrix (Alexander et al., MAPS 50, 2015). In this study, we perform in situ hydrogen isotope analyses at the micrometer scale by secondary ion mass spectrometry to investigate the distribution of organic matter in primitive chondrites without the use of any chemical treatment. Correlated analyses of the D/H and C/H ratios allow us to

  3. Charge exchange in a planetary corona - Its effect on the distribution and escape of hydrogen

    Science.gov (United States)

    Chamberlain, J. W.

    1977-01-01

    The theory for a spherical collisionless planetary corona is extended to include charge-exchange collisions between H(+) and H, which are assumed to constitute intermingled gases with different kinetic temperatures. The treatment is based on the conventional concept of a critical level (or exobase) above which the only collisions considered in the Boltzmann equation are those that resonantly exchange charge. Although the geometry treated is an oversimplification for a real planet, numerical examples are given for an idealized earth and Venus. For earth, an ion temperature of 4 times the neutral temperature, an ion density at the exobase of 14,000 per cu cm, and a plasmapause at 1.5 earth radii will raise the escape flux of H by a factor of 6. The total H above the exobase is changed by less than 1%. For Venus, conditions are examined that would account for the peculiar H distribution observed from Mariner 5. The plasma conditions required are not obviously outrageous by terrestrial standards, but the Mariner 5 ionosphere measurements did not show a high plasmapause at, say, 1.25 or 1.5 planetary radii, a fact that might argue against a charge-exchange model.

  4. Distribution and Composition of Thiotrophic Mats in the Hypoxic Zone of the Black Sea (150–170 m Water Depth, Crimea Margin)

    Science.gov (United States)

    Jessen, Gerdhard L.; Lichtschlag, Anna; Struck, Ulrich; Boetius, Antje

    2016-01-01

    At the Black Sea chemocline, oxygen- and sulfide-rich waters meet and form a niche for thiotrophic pelagic bacteria. Here we investigated an area of the Northwestern Black Sea off Crimea close to the shelf break, where the chemocline reaches the seafloor at around 150–170 m water depth, to assess whether thiotrophic bacteria are favored in this zone. Seafloor video transects were carried out with the submersible JAGO covering 20 km2 on the region between 110 and 200 m depth. Around the chemocline we observed irregular seafloor depressions, covered with whitish mats of large filamentous bacteria. These comprised 25–55% of the seafloor, forming a belt of 3 km width around the chemocline. Cores from the mats obtained with JAGO showed higher accumulations of organic matter under the mats compared to mat-free sediments. The mat-forming bacteria were related to Beggiatoa-like large filamentous sulfur bacteria based on 16S rRNA sequences from the mat, and visual characteristics. The microbial community under the mats was significantly different from the surrounding sediments and enriched with taxa affiliated with polymer degrading, fermenting and sulfate reducing microorganisms. Under the mats, higher organic matter accumulation, as well as higher remineralization and radiotracer-based sulfate reduction rates were measured compared to outside the mat. Mat-covered and mat-free sediments showed similar degradability of the bulk organic matter pool, suggesting that the higher sulfide fluxes and subsequent development of the thiotrophic mats in the patches are consequences of the accumulation of organic matter rather than its qualitative composition. Our observations suggest that the key factors for the distribution of thiotrophic mat-forming communities near to the Crimean shelf break are hypoxic conditions that (i) repress grazers, (ii) enhance the accumulation and degradation of labile organic matter by sulfate-reducers, and (iii) favor thiotrophic filamentous bacteria

  5. Distribution and Composition of Thiotrophic Mats in the Hypoxic Zone of the Black Sea (150-170 m Water Depth, Crimea Margin).

    Science.gov (United States)

    Jessen, Gerdhard L; Lichtschlag, Anna; Struck, Ulrich; Boetius, Antje

    2016-01-01

    At the Black Sea chemocline, oxygen- and sulfide-rich waters meet and form a niche for thiotrophic pelagic bacteria. Here we investigated an area of the Northwestern Black Sea off Crimea close to the shelf break, where the chemocline reaches the seafloor at around 150-170 m water depth, to assess whether thiotrophic bacteria are favored in this zone. Seafloor video transects were carried out with the submersible JAGO covering 20 km(2) on the region between 110 and 200 m depth. Around the chemocline we observed irregular seafloor depressions, covered with whitish mats of large filamentous bacteria. These comprised 25-55% of the seafloor, forming a belt of 3 km width around the chemocline. Cores from the mats obtained with JAGO showed higher accumulations of organic matter under the mats compared to mat-free sediments. The mat-forming bacteria were related to Beggiatoa-like large filamentous sulfur bacteria based on 16S rRNA sequences from the mat, and visual characteristics. The microbial community under the mats was significantly different from the surrounding sediments and enriched with taxa affiliated with polymer degrading, fermenting and sulfate reducing microorganisms. Under the mats, higher organic matter accumulation, as well as higher remineralization and radiotracer-based sulfate reduction rates were measured compared to outside the mat. Mat-covered and mat-free sediments showed similar degradability of the bulk organic matter pool, suggesting that the higher sulfide fluxes and subsequent development of the thiotrophic mats in the patches are consequences of the accumulation of organic matter rather than its qualitative composition. Our observations suggest that the key factors for the distribution of thiotrophic mat-forming communities near to the Crimean shelf break are hypoxic conditions that (i) repress grazers, (ii) enhance the accumulation and degradation of labile organic matter by sulfate-reducers, and (iii) favor thiotrophic filamentous bacteria

  6. Distribution of isotopic composition of hydrogen, oxygen and carbon in the atmosphere of Croatia and Slovenia

    International Nuclear Information System (INIS)

    Krajcar Bronic, I.; Vreca, P.; Horvatincic, N.; Ogrinc, N.; Baresic, J.; Obelic, B.; Kanduc, T.

    2005-01-01

    Natural cycles of water and carbon can be studied by monitoring the isotopic composition of H 2 O and CO 2 in the atmosphere. The monitoring includes isotopes 2 H , 3 H and 1 8O in precipitation, and 1 3C and 1 4C in atmospheric CO 2 . Here we present the results of such a monitoring of the atmosphere over Croatia and Slovenia for the last several years. Monthly precipitation samples at Zagreb and Ljubljana have been collected since 1976 and 1981, respectively. In the period 2000-2003 the sampling network was extended to seven stations along the Adriatic coast of the two countries. Tritium activity in precipitation shows seasonal variations that are most pronounced at inland stations (Zagreb, Ljubljana) followed by the north-Adriatic (Portoroz, Kozina, Malinska) and mid-Adriatic stations (Zadar, Zavizan), and the smallest are at the south-Adriatic stations (Komiza, Dubrovnik). The mean annual tritium activity also decreases from the north to the south of the Adriatic coast. Seasonal variations in delta2 H and delta1 8O in precipitation follow temperature variations at the sampling stations, and the mean annual d 18O values follow mean annual temperatures. Thus, the south-Adriatic stations show the smallest variations in delta1 8O and highest mean delta1 8O values. Atmospheric CO 2 was collected on a monthly basis in Zagreb and Plitvice to record seasonal variations in both Delta1 4C and delta1 3C . Mean annual 1 4C activities in Zagreb decreased after their peak in the 1960s and approached natural pre-bomb activities. For the last three years, the mean 1 4C activity Delta1 4C has remained about 30 per mile. This study extended our knowledge about natural spatial and temporal distributions of 2 H , 3 H , 1 3C , 1 4C and 1 8O in the atmosphere over a relatively small yet rather diverse area in terms of climate and geographic features.(author)

  7. Determination of the ratio r v = d v u v of the valence quark distributions in the proton from neutrino and antineutrino reactions on hydrogen and deuterium

    Science.gov (United States)

    Jones, G. T.; Jones, R. W. L.; Kennedy, B. W.; Klein, H.; Morrison, D. R. O.; Wachsmuth, H.; Miller, D. B.; Mobayyen, M. M.; Wainstein, S.; Aderholz, M.; Hantke, D.; Katz, U. F.; Kern, J.; Schmitz, N.; Wittek, W.; Borner, H. P.; Myatt, G.; Cooper-Sarkar, A. M.; Guy, J.; Venus, W.; Bullock, F. W.; Burke, S.

    1994-12-01

    Based on a QCD analysis of the parton momentum distributions in the proton, the ratio r v = d v / u v of the d and u valence quark distributions is determined as function of x in the range 0.01< x<0.7. The analysis uses data from neutrino and antineutrino charged current interactions on hydrogen and deuterium, obtained with BEBC in the (anti)neutrino wideband beam of the CERN SPS. Since v mainly depends on the deuterium/hydrogen ratios of the normalised x-y-Q 2-distributions many systematic effects cancel. It is found that r v decreases with increasing x, and drops below the naive SU(6) expectation of 0.5 for x≳0.3. An extrapolation of r v to x=1 is consistent with the hypothesis r v (1)=0.

  8. Study of the distribution of hydrogen in a PWR containment with CFD codes; Estudio de la distribucion de hidrogeno en una contencion PWR con codigos CFD

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, G.; Martinez, R. M.; Fernandez, K.; Morato, D. J.; Bocanegra Melian, R.; Mena, L.; Queral, C.

    2014-07-01

    During the development of a severe accident in a PWR reactor can be generated, large quantities of hydrogen by the oxidation of metals present in the nucleus, mainly the zirconium fuel pods. This hydrogen, along with steam and other gases, can be released to the atmosphere of contention by a leak or break in the primary circuit and achieving conditions in which combustion may occur. Combustion causes thermal and pressure loads that can damage the security systems and the integrity of the containment building, last barrier of confinement of radioactive materials. The main condition that defines the characteristics of the combustion is the concentration of species, detailed knowledge of the distribution of hydrogen is very important to correctly predict the possible damage to the containment in the event that there is combustion. (Author)

  9. Spatial Autocorrelation, Source Water and the Distribution of Total and Viable Microbial Abundances within a Crystalline Formation to a Depth of 800 m

    Directory of Open Access Journals (Sweden)

    E. D. Beaton

    2017-09-01

    Full Text Available Proposed radioactive waste repositories require long residence times within deep geological settings for which we have little knowledge of local or regional subsurface dynamics that could affect the transport of hazardous species over the period of radioactive decay. Given the role of microbial processes on element speciation and transport, knowledge and understanding of local microbial ecology within geological formations being considered as host formations can aid predictions for long term safety. In this relatively unexplored environment, sampling opportunities are few and opportunistic. We combined the data collected for geochemistry and microbial abundances from multiple sampling opportunities from within a proposed host formation and performed multivariate mixing and mass balance (M3 modeling, spatial analysis and generalized linear modeling to address whether recharge can explain how subsurface communities assemble within fracture water obtained from multiple saturated fractures accessed by boreholes drilled into the crystalline formation underlying the Chalk River Laboratories site (Deep River, ON, Canada. We found that three possible source waters, each of meteoric origin, explained 97% of the samples, these are: modern recharge, recharge from the period of the Laurentide ice sheet retreat (ca. ∼12000 years before present and a putative saline source assigned as Champlain Sea (also ca. 12000 years before present. The distributed microbial abundances and geochemistry provide a conceptual model of two distinct regions within the subsurface associated with bicarbonate – used as a proxy for modern recharge – and manganese; these regions occur at depths relevant to a proposed repository within the formation. At the scale of sampling, the associated spatial autocorrelation means that abundances linked with geochemistry were not unambiguously discerned, although fine scale Moran’s eigenvector map (MEM coefficients were correlated with

  10. The Atmospheric Distribution of Molecular Hydrogen (H2) and Related Species During HIPPO and Other Recent Airborne Missions

    Science.gov (United States)

    Hintsa, E. J.; Moore, F. L.; Dutton, G. S.; Hall, B. D.; Nance, J. D.; Hurst, D. F.; Novelli, P. C.; Elkins, J. W.; Daube, B.; Kort, E. A.; Pittman, J. V.; Santoni, G. W.; Wofsy, S. C.; Jaegle, L.

    2012-12-01

    focus here is on the distribution of molecular hydrogen (H2), which has a diverse set of atmospheric and terrestrial sources, and a sink term that is dominated by soil uptake. The data show a slight maximum in the southern hemisphere and much greater variability with altitude in the northern hemisphere, broadly consistent with previous studies. Results from the GEOS-Chem model will be presented to allow greater insight into the distribution of H2 and related molecules. Tracer-tracer correlation plots of H2 with methane and CO will also be used to examine the details of the H2 distribution. HIPPO results show a local maximum in H2 at northern hemisphere midlatitudes in spring and early summer, and persistent low values of hydrogen at high northern latitudes long after the soil sink should have decreased with the onset of winter.

  11. Heterogeneous hydrogen distribution in orthopyroxene from veined mantle peridotite (San Carlos, Arizona): Impact of melt-rock interactions

    Science.gov (United States)

    Denis, Carole M. M.; Demouchy, Sylvie; Alard, Olivier

    2018-03-01

    Experimental studies have shown that hydrogen embedded as a trace element in mantle mineral structures affects the physical properties of mantle minerals and rocks. Nevertheless, hydrogen concentrations in mantle minerals are much lower than predicted by hydrogen solubilities obtained experimentally at high pressure and temperature. Here, we report textural analyses and major and trace element concentrations (including hydrogen) in upper mantle minerals from a spinel-bearing composite xenolith (dunite and pyroxenite) transported by silica-undersaturated mafic alkaline lavas from the San Carlos volcanic field (Arizona, USA). Our results suggest that the composite xenolith results from the percolation-reaction of a basaltic liquid within dunite channels, and is equilibrated with respect to trace elements. Equilibrium temperatures range between 1011 and 1023 °C. Hydrogen concentrations (expressed in ppm H2O by weight) obtained from unpolarized and polarized Fourier transform infrared spectroscopy are low, with average values water stored in the Earth's upper mantle.

  12. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Aerosol Optical Depth and Aerosol Particle Size Distribution Environmental Data Record (EDR) from NDE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of aerosol optical depth (AOD) and particle size from the Visible Infrared Imaging...

  13. Measurements of energy distribution and thrust for microwave plasma coupling of electrical energy to hydrogen for propulsion

    Science.gov (United States)

    Morin, T.; Chapman, R.; Filpus, J.; Hawley, M.; Kerber, R.; Asmussen, J.; Nakanishi, S.

    1982-01-01

    A microwave plasma system for transfer of electrical energy to hydrogen flowing through the system has potential application for coupling energy to a flowing gas in the electrothermal propulsion concept. Experimental systems have been designed and built for determination of the energy inputs and outputs and thrust for the microwave coupling of energy to hydrogen. Results for experiments with pressure in the range 100 microns-6 torr, hydrogen flow rate up to 1000 micronmoles/s, and total absorbed power to 700 w are presented.

  14. Quantification of the distribution of hydrogen by nuclear microprobe at the Laboratory Pierre Sue in the width of zirconium alloy fuel clad of PWR reactors

    International Nuclear Information System (INIS)

    Raepsaet, C.; Bossis, Ph.; Hamon, D.; Bechade, J.L.; Brachet, J.C.

    2007-01-01

    Among the analysis techniques by ions beams, the micro ERDA (Elastic Detection Analysis) is an interesting technique which allows the quantitative distribution of the hydrogen in materials. In particular, this analysis has been used for hydride zirconium alloys, with the nuclear microprobe of the Laboratory Pierre Sue. This probe allows the characterization of radioactive materials. The technique principles are recalled and then two examples are provided to illustrate the fuel clad behavior in PWR reactors. (A.L.B.)

  15. Water in Earth's mantle: Hydrogen analysis of mantle olivine, pyroxenes and garnet using the SIMS

    Science.gov (United States)

    Kurosawa, Masanori; Yurimoto, Hisayoshi; Sueno, Shigeho

    1993-01-01

    Hydrogen (or water) in the Earth's interior plays a key role in the evolution and dynamics of the planet. However, the abundance and the existence form of the hydrogen have scarcely been clear in practice. Hydrogen in the mantle was incorporated in the interior during the formation of the Earth. The incorporated hydrogen was hardly possible to concentrate locally inside the Earth considering its high mobility and high reactivity. The hydrogen, preferably, could be distributed homogeneously over the mantle and the core by the subsequent physical and chemical processes. Therefore, hydrogen in the mantle could be present in the form of trace hydrogen in nominally anhydrous mantle minerals. The hydrogen and the other trace elements in mantle olivines, orthopyroxenes, clinopyroxenes, and garnets were determined using secondary ion mass spectrometry (SIMS) for elucidating (1) the exact hydrogen contents, (2) the correlation between the hydrogen and the other trace elements, (3) the dependence of the hydrogen contents on the depth, and (4) the dependence of the whole rock water contents on the depth.

  16. Research on the surface chemical behavior of uranium metal in hydrogen atmosphere by XPS

    International Nuclear Information System (INIS)

    Fu Xiaoguo; Wang Xiaolin; Yu Yong; Zhao Zhengping

    2001-01-01

    The surface chemical behavior clean uranium metal in hydrogen atmosphere at 100 and 200 degree C is studied by X-ray photoelectron spectroscopy (XPS), respectively. It leads to hydriding reaction when the hydrogen exposure is 12.0 Pa·s, and the U4f 7/2 binding energy of UH 3 is found to be 378.7 eV. The higher temperature (200 degree C) is beneficial to UH 3 formation at the same hydrogen exposures. XPS elemental depth profiles indicate that the distribution of uranium surface layer is UO 2 , UH 3 and U after exposure to 174.2 Pa·s hydrogen

  17. ISLSCP II Ecosystem Rooting Depths

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this study was to predict the global distribution of plant rooting depths based on data about global aboveground vegetation structure and climate....

  18. ISLSCP II Ecosystem Rooting Depths

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The goal of this study was to predict the global distribution of plant rooting depths based on data about global aboveground vegetation structure and...

  19. Collision cascades enhanced hydrogen redistribution in cobalt implanted hydrogenated diamond-like carbon films

    International Nuclear Information System (INIS)

    Gupta, P.; Becker, H.-W.; Williams, G.V.M.; Hübner, R.; Heinig, K.-H.; Markwitz, A.

    2017-01-01

    Highlights: • This paper reports for the first time redistribution of hydrogen atoms in diamond like carbon thin films during ion implantation of low energy magnetic ions. • The results point towards new routes of controlling the composition and distribution of elements at the nanoscale within a base matrix without using any heat treatment methods. • Exploring these opportunities can lead to a new horizon of materials and device engineering needed for enabling advanced technologies and applications. - Abstract: Hydrogenated diamond-like carbon films produced by C_3H_6 deposition at 5 kV and implanted at room temperature with 30 keV Co atoms to 12 at.% show not only a bimodal distribution of Co atoms but also a massive redistribution of hydrogen in the films. Resonant nuclear reaction analysis was used to measure the hydrogen depth profiles (15N-method). Depletion of hydrogen near the surface was measured to be as low as 7 at.% followed by hydrogen accumulation from 27 to 35 at.%. A model is proposed considering the thermal energy deposited by collision cascade for thermal insulators. In this model, sufficient energy is provided for dissociated hydrogen to diffuse out of the sample from the surface and diffuse into the sample towards the interface which is however limited by the range of the incoming Co ions. At a hydrogen concentration of ∼35 at.%, the concentration gradient of the mobile unbounded hydrogen atoms is neutralised effectively stopping diffusion towards the interface. The results point towards new routes of controlling the composition and distribution of elements at the nanoscale within a base matrix without using any heat treatment methods. Exploring these opportunities can lead to a new horizon of materials and device engineering needed for enabling advanced technologies and applications.

  20. Collision cascades enhanced hydrogen redistribution in cobalt implanted hydrogenated diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, P. [National Isotope Centre, GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand); Becker, H.-W. [RUBION, Ruhr-University Bochum (Germany); Williams, G.V.M. [The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand); Hübner, R.; Heinig, K.-H. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (Germany); Markwitz, A., E-mail: a.markwitz@gns.cri.nz [National Isotope Centre, GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand)

    2017-03-01

    Highlights: • This paper reports for the first time redistribution of hydrogen atoms in diamond like carbon thin films during ion implantation of low energy magnetic ions. • The results point towards new routes of controlling the composition and distribution of elements at the nanoscale within a base matrix without using any heat treatment methods. • Exploring these opportunities can lead to a new horizon of materials and device engineering needed for enabling advanced technologies and applications. - Abstract: Hydrogenated diamond-like carbon films produced by C{sub 3}H{sub 6} deposition at 5 kV and implanted at room temperature with 30 keV Co atoms to 12 at.% show not only a bimodal distribution of Co atoms but also a massive redistribution of hydrogen in the films. Resonant nuclear reaction analysis was used to measure the hydrogen depth profiles (15N-method). Depletion of hydrogen near the surface was measured to be as low as 7 at.% followed by hydrogen accumulation from 27 to 35 at.%. A model is proposed considering the thermal energy deposited by collision cascade for thermal insulators. In this model, sufficient energy is provided for dissociated hydrogen to diffuse out of the sample from the surface and diffuse into the sample towards the interface which is however limited by the range of the incoming Co ions. At a hydrogen concentration of ∼35 at.%, the concentration gradient of the mobile unbounded hydrogen atoms is neutralised effectively stopping diffusion towards the interface. The results point towards new routes of controlling the composition and distribution of elements at the nanoscale within a base matrix without using any heat treatment methods. Exploring these opportunities can lead to a new horizon of materials and device engineering needed for enabling advanced technologies and applications.

  1. Challenges in the transition toward a hydroge-based society : an in-depth study to assess the potential of a transition to a hydrogen-based energy supply in Europe

    NARCIS (Netherlands)

    Mourik, R.M.; Jeeninga, H.; Groot, de Arend

    2006-01-01

    The Hysociety project, financed under the FP5 framework of the European Commission, aimed to contribute to European policies on hydrogen-related issues through the development of an action plan for the introduction of hydrogen. The geographic target was Europe, focusing on the 15 European Union

  2. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

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

  3. Energy and angular distributions of secondary electrons from 5--100-keV-proton collisions with hydrogen and nitrogen molecules

    International Nuclear Information System (INIS)

    Rudd, M.E.

    1979-01-01

    Cross sections for the ejection of electrons from hydrogen and nitrogen by protons have been measured as a function of the energy and angle of ejection of the electrons at incident proton energies of 5--70 keV and 100 keV for hydrogen. The range of angles measured was 10--160 0 and the electron energy range was 1.5--300 eV. The doubly differential cross sections were also integrated over angle, over electron energy, or over both to obtain singly differential and total cross sections for electron production. Average electron energies were also calculated from the data. The angular distributions of electrons are peaked in the forward direction but become more isotropic as the proton energy decreases. Nitrogen yields a more isotropic distribution than hydrogen. In this range of proton energies the cross sections integrated over angle are found to fall off approximately exponentially with electron energy, and a simple empirical equation has been found that describes the singly differential and total cross sections within a factor of 2 for several targets. A theoretical interpretation of this result in terms of the molecular promotion model is given in which Meyerhof's method of calculating cross sections for K-shell excitation is applied for the first time to the ionization of outer shells of atoms

  4. The impact of aerosol vertical distribution on aerosol optical depth retrieval using CALIPSO and MODIS data : Case study over dust and smoke regions

    NARCIS (Netherlands)

    Wu, Y.; de Graaf, M.; Menenti, M.

    2017-01-01

    Global quantitative aerosol information has been derived from MODerate Resolution Imaging SpectroRadiometer (MODIS) observations for decades since early 2000 and widely used for air quality and climate change research. However, the operational MODIS Aerosol Optical Depth (AOD) products Collection

  5. A depth-adjusted ambient distribution approach for setting numeric removal targets for a Great Lakes Area of Concern beneficial use impairment: Degraded benthos

    Science.gov (United States)

    We compiled and modelled macroinvertebrate assemblage data from samples collected in 1995-2014 from the estuarine portion of the St. Louis River Area of Concern (AOC) of western Lake Superior. Our objective to create depth-adjusted cutoff values for benthos condition classes (po...

  6. Measurement of hydrogen distributions in iron and steel by means of neutron radiography and tomography; Messung von Wasserstoffverteilungen in Eisen und Stahl mittels Neutronenradiographie und -tomographie

    Energy Technology Data Exchange (ETDEWEB)

    Griesche, Axel; Kannengiesser, Thomas [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Kardjilov, Nikolay; Manke, Ingo [Helmholtz-Zentrum Berlin (HZB), Berlin (Germany); Schillinger, Burkhard [Technische Univ. Muenchen, Garching (Germany)

    2015-07-01

    In recent years, the optimization of the radiography measuring stations at research reactors and in particular the development of the neutron detectors has enabled the measurement of hydrogen distributions with ever higher spatial resolution at the same time more sensitive detection limit. Compared to iron, hydrogen has a high interaction cross-section for neutrons, and thus allows simple radiographic methods of the two and three dimensional visualization of hydrogen distribution in the structure. This allowed us for the first time the measurement of hydrogen diffusion flows in centimeter-thick steel samples with a temporal resolution of 20 s and the quantitative measurement of hydrogen accumulation of crack edges in hydrogen embrittled iron samples. It was also the first gaseous hydrogen detected in the cavities of the cracks and the pressure can be determined. This new quality of information on the microstructure scale granted unprecedented insights for the investigation of damage mechanisms e.g. in the hydrogen embrittlement. By providing local in-situ information that is not accessible by conventional methods such as carrier gas hot extraction, as well as analyzes can be performed in three dimensions with a spatial resolution of 20-30 μm. This article provides examples that use the spatial and temporal resolution of the neutron radiography and tomography to visualize hydrogen distributions in and around cracks and to quantify. The measurements were conducted at the research reactors BER II of HZB in Berlin and FRM II of teh neutron source Heinz Maier-Leibnitz in Garching. (This article contains PowerPoint slides). [German] In den letzten Jahren hat die Optimierung der Radiographie-Messplaetze an Forschungsreaktoren und hier insbesondere die Weiterentwicklung der Neutronendetektoren die Messung von Wasserstoffverteilungen mit immer hoeherer Ortsaufloesung bei gleichzeitig empfindlicherer Nachweisgrenze ermoeglicht. Wasserstoff besitzt im Vergleich zu Eisen

  7. Occurrence and distribution of color and hydrogen sulfide in water of the principal artesian aquifers in the Valdosta area, Georgia

    Science.gov (United States)

    Krause, Richard E.

    1976-01-01

    Hydrogen sulfide and color occur in objectionable amounts in ground water from the principal artesian aquifer in the Valdosta , Ga., area. Generally, water from wells south of Valdosta is high in hydrogen sulfide; water from wells north of the city is high in color. Water with high sulfate is likely to be a problem in wells deeper than about 540 ft. Heavy pumpage concentrated in a small area may cause high-sulfate water to migrate vertically upward into shallower wells. (Woodard-USGS)

  8. Hydrogen energy

    International Nuclear Information System (INIS)

    2005-03-01

    This book consists of seven chapters, which deals with hydrogen energy with discover and using of hydrogen, Korean plan for hydrogen economy and background, manufacturing technique on hydrogen like classification and hydrogen manufacture by water splitting, hydrogen storage technique with need and method, hydrogen using technique like fuel cell, hydrogen engine, international trend on involving hydrogen economy, technical current for infrastructure such as hydrogen station and price, regulation, standard, prospect and education for hydrogen safety and system. It has an appendix on related organization with hydrogen and fuel cell.

  9. Effect of the spatial distribution of physical aquifer properties on modelled water table depth and stream discharge in a headwater catchment

    Directory of Open Access Journals (Sweden)

    C. Gascuel-Odoux

    2010-07-01

    Full Text Available Water table depth and its dynamics on hillslopes are often poorly predicted despite they control both water transit time within the catchment and solute fluxes at the catchment outlet. This paper analyses how relaxing the assumption of lateral homogeneity of physical properties can improve simulations of water table depth and dynamics. Four different spatial models relating hydraulic conductivity to topography have been tested: a simple linear relationship, a linear relationship with two different topographic indexes, two Ks domains with a transitional area. The Hill-Vi model has been modified to test these hypotheses. The studied catchment (Kervidy-Naizin, Western France is underlain by schist crystalline bedrock. A shallow and perennial groundwater highly reactive to rainfall events mainly develops in the weathered saprolite layer. The results indicate that (1 discharge and the water table in the riparian zone are similarly predicted by the four models, (2 distinguishing two Ks domains constitutes the best model and slightly improves prediction of the water table upslope, and (3 including spatial variations in the other parameters such as porosity or rate of hydraulic conductivity decrease with depth does not improve the results. These results underline the necessity of better investigations of upslope areas in hillslope hydrology.

  10. Report on the results of the FY 1998 hydrogen utilization international clean energy system technology (WE-NET). Subtask 5. Survey on the R and D of technologies for hydrogen transport and storage by hydrogen absorbing alloys (V. Development of the distributed transport/storage use hydrogen absorbing alloys); 1998 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET). 5. Suiso yuso chozo gijutsu no kaihatsu (V. bunsan yuso chozoyo suiso kyuzo gokin no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The paper described the FY 1998 results of the development of hydrogen distributed transport/storage use absorbing alloys in the WE-NET project. Study was made of improvement of hydrogen desorption characteristics by substituting Ca for part of Mg of Mg-Ni alloys and substituting Cr for part of Ni. It is necessary to shift the state of atomic bond by H atom and metal atom in alloys from the ionic bond to the metallic bond, and to change from the amorphous state to the BCC type crystal structure. It was found out that it was possible to do it by improving the composition and heat treatment. The addition of Cu to LaMg{sub 2} alloys shifts the bond with hydrogen to the bond with metal. Easy hydrogen desorption and large absorbing capacity can be expected. It was found out that LaMg{sub 2}Cu{sub 2} synthesized by the reaction sintering method has reversible hydrogen absorbing desorption characteristics. The absorbing amount is 2.4 wt%, the desorption amount 1.2 wt%, and the desorption temperature 190 degrees C. Those are still far from WE-NET targeted values, but a clue to the search was obtained. It was found out that by applying doping technology by Ti, etc. to NaAlH{sub 4}, characteristics can be expected of the desorption amount, 4.5 wt%, of the hydrogen desorption starting temperature from 100 degrees C to 200 degrees C. (NEDO)

  11. Charge state distribution of ^{86}Kr in hydrogen and helium gas charge strippers at 2.7  MeV/nucleon

    Directory of Open Access Journals (Sweden)

    H. Kuboki

    2014-12-01

    Full Text Available The charge state distributions of krypton (^{86}Kr with an energy of 2.7  MeV/nucleon were measured using hydrogen (H_{2} and helium (He gas charge strippers. A differential pumping system was constructed to confine H_{2} and He gases to a thickness sufficient for the charge state distributions to attain equilibrium. The mean charge states of ^{86}Kr in H_{2} and He gases attained equilibrium at 25.1 and 23.2, respectively, whereas the mean charge state in N_{2} gas at equilibrium was estimated to be less than 20. The charge distributions are successfully reproduced by the cross sections of ionization and electron capture processes optimized by a fitting procedure.

  12. Development of hydrogen market: the outlook for demand, wing energy production, mass storage and distribution to vehicles in the regions; Developpement des marches de l'hydrogene demande prospective dans l'industrie, production par energie eolienne, stockage massif et distribution aux vehicules en region

    Energy Technology Data Exchange (ETDEWEB)

    Le Duigou, A. [CEA Saclay, DEN/DANS/I-Tese, 91 - Gif-sur-Yvette (France); Quemere, M.M. [EDF R and D, 77 - Moret-Sur- Loing (France); Marion, P.; Decarre, S. [IFP Energies nouvelles, 92 - Rueil-Malmaison (France); Sinegre, L.; Nadau, L.; Pierre, H. [GDF SUEZ, DRI, 93 - La Plaine Saint Denis (France); Menanteau, Ph. [LEPII, Universite de Grenoble - CNRS, 38 (France); Rastetter, A. [ALPHEA, EURODEV Center, 57 - Forbach (France); Cuni, A.; Barbier, F. [Air Liquide, 75 - Paris (France); Mulard, Ph. [Total, La Defense, Raffige Marketing, 92 - Courbevoie (France); Alleau, Th. [AFH2, 75 - Paris (France); Antoine, L. [ADEME, Agence de l' Environnement et de la Maitrise de l' Energie, 75 - Paris (France)

    2011-03-15

    The HyFrance3 project has provided a national framework for reflection, debate and strategic exchange between major public and industrial research players, namely for their hydrogen technology arms in France (Air Liquide, Total Refining and Marketing, EDF R and D, GDF SUEZ, CNRS-LEPII Energies Nouvelles, AFH2, ALPHEA, ADEME (co-financing and partner) and the CEA (coordinator)). This project focuses on studying the landscape, trends and economic competitiveness of some links in the hydrogen chain, for industrial and energy applications, over a period referred to as 'short term' (2020-2030). Four study subjects were tackled: the prospective demand for hydrogen in industry (analysis of the current situation and outlook for 2030, in particular for refining based on two scenarios on mobility), production of hydrogen for transport uses from wind-produced electricity, mass storage that would have to be set up in the Rhone Alpes and PACA regions, to balance supply that is subject to deliberate (maintenance) or involuntary interruptions, and the distribution of hydrogen in the region, for automobile use (gas station network in the Rhone Alpes and PACA regions) by 2050 (with end period all-in costs between 0.4 eur/kg and 0.6 eur/kg, as a function of the price of energy and the distance from the storage site). (authors)

  13. Fuel Cell Power Model Version 2: Startup Guide, System Designs, and Case Studies. Modeling Electricity, Heat, and Hydrogen Generation from Fuel Cell-Based Distributed Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Steward, D.; Penev, M.; Saur, G.; Becker, W.; Zuboy, J.

    2013-06-01

    This guide helps users get started with the U.S. Department of Energy/National Renewable Energy Laboratory Fuel Cell Power (FCPower) Model Version 2, which is a Microsoft Excel workbook that analyzes the technical and economic aspects of high-temperature fuel cell-based distributed energy systems with the aim of providing consistent, transparent, comparable results. This type of energy system would provide onsite-generated heat and electricity to large end users such as hospitals and office complexes. The hydrogen produced could be used for fueling vehicles or stored for later conversion to electricity.

  14. ITAR: A modified TAR method to determine depth dose distribution for an ophthalmic device that performs kilovoltage x-ray pencil-beam stereotaxy

    International Nuclear Information System (INIS)

    Hanlon, Justin; Chell, Erik; Firpo, Michael; Koruga, Igor

    2014-01-01

    Purpose: New technology has been developed to treat age-related macular degeneration (AMD) using 100 kVp pencil-beams that enter the patient through the radio-resistant sclera with a depth of interest between 1.6 and 2.6 cm. Measurement of reference and relative dose in a kilovoltage x-ray beam with a 0.42 cm diameter field size and a 15 cm source to axis distance (SAD) is a challenge that is not fully addressed in current guidelines to medical physicists. AAPM's TG-61 gives dosimetry recommendations for low and medium energy x-rays, but not all of them are feasible to follow for this modality. Methods: An investigation was conducted to select appropriate equipment for the application. PTW's Type 34013 Soft X-Ray Chamber (Freiburg, Germany) and CIRS's Plastic Water LR (Norfolk, VA) were found to be the best available options. Attenuation curves were measured with minimal scatter contribution and thus called Low Scatter Tissue Air Ratio (LSTAR). A scatter conversion coefficient (C scat ) was derived through Monte Carlo radiation transport simulation using MCNPX (LANL, Los Alamos, NM) to quantify the difference between a traditional TAR curve and the LSTAR curve. A material conversion coefficient (C mat ) was determined through experimentation to evaluate the difference in attenuation properties between water and Plastic Water LR. Validity of performing direct dosimetry measurements with a source to detector distance other than the treatment distance, and therefore a different field size due to a fixed collimator, was explored. A method—Integrated Tissue Air Ratio (ITAR)—has been developed that isolates each of the three main radiological effects (distance from source, attenuation, and scatter) during measurement, and integrates them to determine the dose rate to the macula during treatment. Results: LSTAR curves were determined to be field size independent within the range explored, indicating that direct dosimetry measurements may be performed with a source to

  15. ITAR: A modified TAR method to determine depth dose distribution for an ophthalmic device that performs kilovoltage x-ray pencil-beam stereotaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hanlon, Justin, E-mail: jhanlon@orayainc.com; Chell, Erik; Firpo, Michael; Koruga, Igor [Oraya Therapeutics, Inc., Newark, California 94560 (United States)

    2014-02-15

    Purpose: New technology has been developed to treat age-related macular degeneration (AMD) using 100 kVp pencil-beams that enter the patient through the radio-resistant sclera with a depth of interest between 1.6 and 2.6 cm. Measurement of reference and relative dose in a kilovoltage x-ray beam with a 0.42 cm diameter field size and a 15 cm source to axis distance (SAD) is a challenge that is not fully addressed in current guidelines to medical physicists. AAPM's TG-61 gives dosimetry recommendations for low and medium energy x-rays, but not all of them are feasible to follow for this modality. Methods: An investigation was conducted to select appropriate equipment for the application. PTW's Type 34013 Soft X-Ray Chamber (Freiburg, Germany) and CIRS's Plastic Water LR (Norfolk, VA) were found to be the best available options. Attenuation curves were measured with minimal scatter contribution and thus called Low Scatter Tissue Air Ratio (LSTAR). A scatter conversion coefficient (C{sub scat}) was derived through Monte Carlo radiation transport simulation using MCNPX (LANL, Los Alamos, NM) to quantify the difference between a traditional TAR curve and the LSTAR curve. A material conversion coefficient (C{sub mat}) was determined through experimentation to evaluate the difference in attenuation properties between water and Plastic Water LR. Validity of performing direct dosimetry measurements with a source to detector distance other than the treatment distance, and therefore a different field size due to a fixed collimator, was explored. A method—Integrated Tissue Air Ratio (ITAR)—has been developed that isolates each of the three main radiological effects (distance from source, attenuation, and scatter) during measurement, and integrates them to determine the dose rate to the macula during treatment. Results: LSTAR curves were determined to be field size independent within the range explored, indicating that direct dosimetry measurements may be

  16. The spatial distribution and velocity field of the molecular hydrogen line emission from the centre of the Galaxy

    International Nuclear Information System (INIS)

    Gatley, I.; Krisciunas, K.; Jones, T.J.; Hyland, A.R.; Geballe, T.R.; Rijksuniversiteit Groningen

    1986-01-01

    In an earlier paper the existence of a ring of molecular hydrogen-line emission surrounding the nucleus of the Galaxy was demonstrated. Here are presented the first detailed maps of the surface brightness and the velocity field, made in the upsilon=1-0 S(1) line of molecular hydrogen with a spatial resolution of 18 arcsec and a velocity resolution of 130 km s -1 . It is found that the molecular ring is tilted approximately 20 0 out of the plane of the Galaxy, has a broken and clumpy appearance, rotates at 100 km s -1 in the sense of galactic rotation, and exhibits radial motion at a velocity of 50 km s -1 . (author)

  17. Measuring the distribution of equity in terms of energy, environmental, and economic costs in the fuel cycles of alternative fuel vehicles with hydrogen pathway scenarios

    Science.gov (United States)

    Meyer, Patrick E.

    Numerous analyses exist which examine the energy, environmental, and economic tradeoffs between conventional gasoline vehicles and hydrogen fuel cell vehicles powered by hydrogen produced from a variety of sources. These analyses are commonly referred to as "E3" analyses because of their inclusion of Energy, Environmental, and Economic indicators. Recent research as sought a means to incorporate social Equity into E3 analyses, thus producing an "E4" analysis. However, E4 analyses in the realm of energy policy are uncommon, and in the realm of alternative transportation fuels, E4 analyses are extremely rare. This dissertation discusses the creation of a novel E4 simulation tool usable to weigh energy, environmental, economic, and equity trade-offs between conventional gasoline vehicles and alternative fuel vehicles, with specific application to hydrogen fuel cell vehicles. The model, dubbed the F uel Life-cycle Analysis of Solar Hydrogen -- Energy, Environment, Economic & Equity model, or FLASH-E4, is a total fuel-cycle model that combines energy, environmental, and economic analysis methodologies with the addition of an equity analysis component. The model is capable of providing results regarding total fuel-cycle energy consumption, emissions production, energy and environmental cost, and level of social equity within a population in which low-income drivers use CGV technology and high-income drivers use a number of advanced hydrogen FCV technologies. Using theories of equity and social indicators conceptually embodied in the Lorenz Curve and Gini Index, the equity of the distribution of societal energy and environmental costs are measured for a population in which some drivers use CGVs and other drivers use FCVs. It is found, based on baseline input data representative of the United States (US), that the distribution of energy and environmental costs in a population in which some drivers use CGVs and other drivers use natural gas-based hydrogen FCVs can be

  18. Application of the high-temperature ratio method for evaluation of the depth distribution of dose equivalent in a water-filled phantom on board space station Mir

    International Nuclear Information System (INIS)

    Berger, T.; Hajek, M.; Schoener, W.; Fugger, M.; Vana, N.; Akatov, Y.; Shurshakov, V.; Arkhangelsky, V.; Kartashov, D.

    2002-01-01

    A water-filled tissue equivalent phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems, Moscow, Russia. It contains four channels perpendicular to each other, where dosemeters can be exposed at different depths. Between May 1997 and February 1999 the phantom was installed at three different locations on board the Mir space station. Thermoluminescence dosemeters (TLDs) were exposed at various depths inside the phantom either parallel or perpendicular to the hull of the spacecraft. The high-temperature ratio (HTR) method was used for the evaluation of the TLDs. The method was developed at the Atominstitute of the Austrian Universities, Vienna, Austria, and has already been used for measurements in mixed radiation fields on earth and in space with great success. It uses the changes of peak height ratios in LiF:Mg,Ti glow curves in dependence on the linear energy transfer (LET), and therefore allows determination of an 'averaged' LET as well as measurement of the absorbed dose. A mean quality factor and, subsequently, the dose equivalent can be calculated according to the Q(LET ( ) relationship proposed by the ICRP. The small size of the LiF dosemeters means that the HTR method can be used to determine the gradient of absorbed dose and dose equivalent inside the tissue equivalent body. (author)

  19. Development of Innovating Materials for Distributing Mixtures of Hydrogen and Natural Gas. Study of the Barrier Properties and Durability of Polymer Pipes

    Directory of Open Access Journals (Sweden)

    Klopffer Marie-Hélène

    2015-02-01

    Full Text Available With the growing place taken by hydrogen, a question still remains about its delivery and transport from the production site to the end user by employing the existing extensive natural gas pipelines. Indeed, the key challenge is the significant H2 permeation through polymer infrastructures (PolyEthylene (PE pipes, components such as connecting parts. This high flow rate of H2 through PE has to be taken into account for safety and economic requirements. A 3-year project was launched, the aim of which was to develop and assess material solutions to cope with present problems for hydrogen gas distribution and to sustain higher pressure compared to classical high density polyethylene pipe. This project investigated pure hydrogen gas and mixtures with natural gas (20% of CH4 and 80% of H2 in pipelines with the aim to select engineering polymers which are more innovative than polyethylene and show outstanding properties, in terms of permeation, basic mechanical tests but also more specific characterizations such as long term ageing and behaviour. The adequate benches, equipments and scientific approach for materials testing had been developed and validated. In this context, the paper will focus on the evaluation of the barrier properties of 3 polymers (PE, PA11 and PAHM. Experiments were performed for pure H2 and CH4 and also in the presence of mixtures of hydrogen and natural gas in order to study the possible mixing effects of gases. It will report some round-robin tests that have been carried out. Secondly, by comparing data obtained on film, polymer membrane and on pipe section, the influence of the polymer processing will be studied. Innovative multilayers systems will be proposed and compared on the basis of the results obtained on monolayer systems. Finally, the evolution of the transport properties of the studied polymers with an ageing under representative service conditions will be discussed.

  20. Hydrogen, energy of the future?

    International Nuclear Information System (INIS)

    Alleau, Th.

    2007-01-01

    A cheap, non-polluting energy with no greenhouse gas emissions and unlimited resources? This is towards this fantastic future that this book brings us, analyzing the complex but promising question of hydrogen. The scientific and technical aspects of production, transport, storage and distribution raised by hydrogen are thoroughly reviewed. Content: I) Energy, which solutions?: 1 - hydrogen, a future; 2 - hydrogen, a foreseeable solution?; II) Hydrogen, an energy vector: 3 - characteristics of hydrogen (physical data, quality and drawbacks); 4 - hydrogen production (from fossil fuels, from water, from biomass, bio-hydrogen generation); 5 - transport, storage and distribution of hydrogen; 6 - hydrogen cost (production, storage, transport and distribution costs); III) Fuel cells and ITER, utopias?: 7 - molecular hydrogen uses (thermal engines and fuel cells); 8 - hydrogen and fusion (hydrogen isotopes, thermonuclear reaction, ITER project, fusion and wastes); IV) Hydrogen acceptability: 9 - risk acceptability; 10 - standards and regulations; 11 - national, European and international policies about hydrogen; 12 - big demonstration projects in France and in the rest of the world; conclusion. (J.S.)

  1. Chain-Length Distribution and Hydrogen Isotopic Fraction of n-alkyl Lipids in Aquatic and Terrestrial Plants: Implications for Paleoclimate Reconstructions

    Science.gov (United States)

    Gao, L.; Littlejohn, S.; Hou, J.; Toney, J.; Huang, Y.

    2008-12-01

    Recent studies demonstrate that in lacustrine sediments, aquatic plant lipids (e.g., C22-fatty acid) record lake water D/H ratio variation, while long-chain fatty acids (C26-C32, major components of terrestrial plant leaf waxes), record D/H ratios of precipitation (especially in arid regions). However, there are insufficient literature data for the distribution and hydrogen isotopic fractionation of n-alkyl lipids in aquatic and terrestrial plants. In this study, we determined the chain-length distributions and D/H ratios of n-alkyl lipids from 17 aquatic plant species (9 emergent, 4 floating and 4 submerge species) and 13 terrestrial plant species (7 grasses and 6 trees) from Blood Pond, Massachusetts. Our results are consistent with previous studies and provide a solid basis for the paleoclimatic reconstruction using D/H ratios of aquatic and terrestrial plant biomarkers. In addition, systematic hydrogen isotopic analyses on leaf waxes, leaf, stem and soil waters from trees and grasses significantly advance our understanding of our previously observed large D/H ratio difference between tree and grass leaf waxes. Our data indicate that the observed difference is not due to differences in leaf water D/H ratios. In comparison with grasses, trees use greater proportion of D-enriched residual or stored carbohydrates (as opposed to current photosynthetic carbohydrates) for leaf wax biosynthesis, resulting in higher leaf wax D/H ratios. The residual carbohydrates are enriched in deuterium because of the preferential consumption of light-hydrogen substrates during plant metabolism.

  2. Hydrogen interaction with oxidized Si(111) probed with positrons

    International Nuclear Information System (INIS)

    Lynn, K.G.; Nielsen, B.; Welch, D.O.

    1989-01-01

    A variable-energy positron beam was utilized to study the interface action of hydrogen with Si(111) covered by an ultrahigh-vacuum thermally grown oxide of 2-3 nm thickness. It was observed that positrons implanted at shallow depth (< 100 nm) after diffusion are trapped either at the interface between the oxide and the Si or in the oxide. The positron-annihilation characteristics of these trapped positrons are found to be very sensitive to hydrogen exposure. The momentum distribution of the annihilating positron-electron pair, as observed in the Doppler broadening of the annihilation line, broadens considerably after exposure to hydrogen. The effect recovers after annealing at ≅ 1100 K, suggesting a hydrogen binding at the interface of ∼ 3 ± 0.3 eV. (author). 18 refs., 3 figs

  3. Future hydrogen markets for large-scale hydrogen production systems

    International Nuclear Information System (INIS)

    Forsberg, Charles W.

    2007-01-01

    The cost of delivered hydrogen includes production, storage, and distribution. For equal production costs, large users (>10 6 m 3 /day) will favor high-volume centralized hydrogen production technologies to avoid collection costs for hydrogen from widely distributed sources. Potential hydrogen markets were examined to identify and characterize those markets that will favor large-scale hydrogen production technologies. The two high-volume centralized hydrogen production technologies are nuclear energy and fossil energy with carbon dioxide sequestration. The potential markets for these technologies are: (1) production of liquid fuels (gasoline, diesel and jet) including liquid fuels with no net greenhouse gas emissions and (2) peak electricity production. The development of high-volume centralized hydrogen production technologies requires an understanding of the markets to (1) define hydrogen production requirements (purity, pressure, volumes, need for co-product oxygen, etc.); (2) define and develop technologies to use the hydrogen, and (3) create the industrial partnerships to commercialize such technologies. (author)

  4. Hydrogen storage container

    Science.gov (United States)

    Wang, Jy-An John; Feng, Zhili; Zhang, Wei

    2017-02-07

    An apparatus and system is described for storing high-pressure fluids such as hydrogen. An inner tank and pre-stressed concrete pressure vessel share the structural and/or pressure load on the inner tank. The system and apparatus provide a high performance and low cost container while mitigating hydrogen embrittlement of the metal tank. System is useful for distributing hydrogen to a power grid or to a vehicle refueling station.

  5. Mitigation of Hydrogen Hazards in Severe Accidents in Nuclear Power Plants

    International Nuclear Information System (INIS)

    2011-07-01

    Consideration of severe accidents in nuclear power plants is an essential component of the defence in depth approach in nuclear safety. Severe accidents have very low probabilities of occurring, but may have significant consequences resulting from the degradation of nuclear fuel. The generation of hydrogen and the risk of hydrogen combustion, as well as other phenomena leading to overpressurization of the reactor containment in case of severe accidents, represent complex safety issues in relation to accident management. The combustion of hydrogen, produced primarily as a result of heated zirconium metal reacting with steam, can create short term overpressure or detonation forces that may exceed the strength of the containment structure. An understanding of these phenomena is crucial for planning and implementing effective accident management measures. Analysis of all the issues relating to hydrogen risk is an important step for any measure that is aimed at the prevention or mitigation of hydrogen combustion in reactor containments. The main objective of this publication is to contribute to the implementation of IAEA Safety Standards, in particular, two IAEA Safety Requirements: Safety of Nuclear Power Plants: Design and Safety of Nuclear Power Plants: Operation. These Requirements publications discuss computational analysis of severe accidents and accident management programmes in nuclear power plants. Specifically with regard to the risk posed by hydrogen in nuclear power reactors, computational analysis of severe accidents considers hydrogen sources, hydrogen distribution, hydrogen combustion and control and mitigation measures for hydrogen, while accident management programmes are aimed at mitigating hydrogen hazards in reactor containments.

  6. The depth distribution functions of the natural abundances of carbon isotopes in Alfisols thoroughly sampled by thin-layer sampling, and their relation to the dynamics of organic matter in theses soils

    International Nuclear Information System (INIS)

    Becker-Heidmann, P.

    1989-01-01

    The aim of this study was to gain fundamental statements on the relationship between the depth distributions of the natural abundances of 13 C and 14 C isotopes and the dynamics of the organic matter in Alfisols. For this purpose, six Alfisols were investigated: four forest soils from Northern Germany, two of them developed in Loess and two in glacial loam, one West German Loess soil used for fruit-growing and one agricultural granite-gneiss soil from the semiarid part of India. The soil was sampled as succesive horizontal layers of 2 cm depth from an area of 0.5 to 1 m 2 size, starting from the organic down to the C horizon or the lower part of the Bt. This kind of completely thin-layer-wise sampling was applied here for the first time. The carbon content and the natural abundances of the 13 C and the 14 C isotopes of each sample were determined. The δ 13 C value was measured by mass spectrometry. A vacuum preparation line with an electronically controlled cooling unit was constructed thereto. For the determination of the 14 C content, the sample carbon was transferred into benzene, and its activity was measured by liquid scintillation spectrometry. From the combination of the depth distribution functions of the 14 C activity and the δ 13 C value, and with the aid of additional analyses like C/N ratio and particle size distribution, a conclusive interpretation as to the dynamics of the organic matter in the investigated Alfisols is given. (orig./BBR)

  7. Hydrogen and fuel cells

    International Nuclear Information System (INIS)

    2006-06-01

    This road-map proposes by the Group Total aims to inform the public on the hydrogen and fuel cells. It presents the hydrogen technology from the production to the distribution and storage, the issues as motor fuel and fuel cells, the challenge for vehicles applications and the Total commitments in the domain. (A.L.B.)

  8. Oils from different depth in the Alagoas sub-basin distribution and concentration; Oleos em diferentes profundidades na sub-bacia Alagoas: distribuicao e econcentracao

    Energy Technology Data Exchange (ETDEWEB)

    Reboucas, Lucia M.C.; Sant' Ana, Antonio E.G.; Sabino, Adilson R.; Nogueira, Fred A.R.; Moraes, Reinaldo J.R.; Crispim, Alessandre [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Inst. de Quimica e Biotecnologia . Lab. de Analises de Biomarcadores e Semioquimicos]. E-mail: lmcr@qui.ufal.br

    2008-07-01

    This paper reports the distribution and the concentration of n-alkane homologue series and the HPA compounds in 22 oils from Alagoas sub-basin, Pilar Field, Brazil. The n-alkane profile of whole oil gas chromatograms (CG-FID) to light, medium and heave oils represented no-biodegraded oils. The light and medium oils have n-alkane distribution with a maximum in nC{sub 10} and nC{sub 17}. The ration pristine/phytane (P/F) between 1,5 and 2,7 suggest Lacustrine origin. The nalkane distribution from the heavy oils show two maximum between nC{sub 15} and nC{sub 23}. The concentrations of n-alkane are different to all the 22 oils. The F2 fraction classified as light (API>39), medium (36

  9. FY 1974 report on the results of the Sunshine Project. Study of the hydrogen safety technology (Study of the hydrogen safety technology in the distribution/consumption process); 1974 nendo suiso no hoan gijutsu no kenkyu seika hokokusho. Suiso no ryutsu shohi process ni okeru hoan gijutsu no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-05-25

    To put it forcibly, the gas leakage problem should be solved to prevent disaster accidents caused by high pressure gas. From this point of view, the R and D of the safety technology were conducted for the process of hydrogen distribution/consumption. The literature collected was studied, and the present situation was again recognized of the hydrogen gas industrial circle in Japan. At the same time, hydrogen physical properties and the peculiar dangers derived therefrom were comprehensively arranged. Examples of accidents tell realistically how dangerous hydrogen is, and give suggestions for treating hydrogen safely. We can see a lot of examples of how to treat liquid hydrogen in the U.S. It seems that there are no effective methods to detect the leakage of hydrogen, and methods to meet each case are required. To sum up, the research results show how much safety of the distribution/consumption process is secured under the present safety technology and legal regulation. At the same time, those also indicate how much the safety can be enhanced technically in the future. (NEDO)

  10. Oxygen isotopic distribution along the otolith growth axis by secondary ion mass spectrometry: Applications for studying ontogenetic change in the depth inhabited by deep-sea fishes

    Science.gov (United States)

    Shiao, Jen-Chieh; Itoh, Shoichi; Yurimoto, Hisayoshi; Iizuka, Yoshiyuki; Liao, Yun-Chih

    2014-02-01

    This study using tuna otoliths as working standards established a high lateral resolution and precision analysis to measure δ18Ootolith by secondary ion mass spectrometry. This analytical approach of the ion probe was applied to deep-sea fishes to reconstruct the likely depths inhabited by the fishes at different life history stages based on the measured δ18Ootolith values as a proxy of water temperature. Dramatic increases up to 5-6‰ in δ18Ootolith, representing a temperature decrease of approximately 20 °C, were detected in a blind cusk eel (Barathronus maculatus) otolith and in the otoliths of Synaphobranchus kaupii during leptocephalus metamorphosis to glass eel, inferred from the drop of otolith Sr/Ca ratios and increase of otolith growth increment width. δ18Ootolith profiles clearly divided the fish's life history into a planktonic stage in the mixed layer of the ocean and a benthic stage on the deep-sea ocean bottom. The habitat shift signal was recorded within a 150 μm width of otolith growth zone, which was too narrow to be clearly detected by mechanical drilling and conventional isotopic ratio mass spectrometry. However, variations down to -7‰ were found in δ18Ootolith profiles as the result of Cs2+ beam sputter in the core and larval portions of the otoliths. Carbon mapping by electron probe microanalyzer and staining by toluidine blue suggested abundant proteins existed in the areas with anomaly negative δ18Ootolith values, which cannot be interpreted as a habitat change but due to the isotopic fractionation by O emission from the proteins. These results implied that careful design and understanding of the chemical composition of the analytical areas or tracks on the heterogeneous otolith was essential for highly accurate and precise analysis.

  11. Investigating the Relationships between Canopy Characteristics and Snow Depth Distribution at Fine Scales: Preliminary Results from the SnowEX TLS Campaign

    Science.gov (United States)

    Glenn, N. F.; Uhlmann, Z.; Spaete, L.; Tennant, C.; Hiemstra, C. A.; McNamara, J.

    2017-12-01

    Predicting changes in forested seasonal snowpacks under altered climate scenarios is one of the most pressing hydrologic challenges facing today's society. Airborne- and satellite-based remote sensing methods hold the potential to transform measurements of terrestrial water stores in snowpack, improve process representations of snowpack accumulation and ablation, and to generate high quality predictions that inform potential strategies to better manage water resources. While the effects of forest on snowpack are well documented, many of the fine-scale processes influenced by the forest-canopy are not directly accounted for because most snow models don't explicitly represent canopy structure and canopy heterogeneity. This study investigates the influence of forest canopy on snowpack distribution at fine scales and quantifies the influence of canopy heterogeneity on snowpack accumulation and ablation processes. We use terrestrial laser scanning (TLS) data collected during the SnowEX campaign to discover how the relationships between canopy and snow distributions change across scales. Our sample scales range from individual trees to patches of trees across the Grand Mesa, CO, SnowEx site.

  12. Hydrogen diffusion and microstructure in undoped and boron-dope hydrogenated amorphous silicon: An IR and SIMS study

    International Nuclear Information System (INIS)

    Mitra, S.

    1991-01-01

    Hydrogenated amorphous silicon (a-Si:H) prepared by rf sputtering of a polycrystalline Si target at various rf powers 50 ≤ P ≤ 550 W (0.27--2.97 W/cm 2 ), target to substrate distance 1 ≤ d ≤ 2 double-prime, and varying hydrogen partial pressures. Doping was accomplished by introducing diborane (B 2 H 6 ) in the plasma. Hydrogen diffusion was studied from the depth profiles obtained from the SIMS on multilayered a-Si:H/a-Si:(H,D)/a-Si:H samples. The properties of the samples were characterized by IR absorption, optical gap measurements and ESR. IR yielded quantitative and qualitative information total hydrogen content and the nature of the hydrogen bonding, respectively. Hence the hydrogen microstructure of the samples could be varied in a systematic manner and monitored from the hydrogen vibrational modes. The ESR gave information on the number of paramagnetic defects per unit volume in the samples. The IR absorption of both as-deposited and annealed samples were closely monitored and the results clearly demonstrate a strong correlation between hydrogen diffusion and its microstructure. It is shown that microvoids in a-Si:H play a critical role in the process of diffusion by inducing deep hydrogen trapping sites that render them immobile. Consequently, as the microvoid density increases beyond a critical density hydrogen diffusion is totally quenched. The diffusion results are discussed both in the context of multiple trapping transport of hydrogen in an exponential distribution of trapping sites and the floating bond model

  13. Improvement effect on the depth-dose distribution by CSF drainage and air infusion of a tumour-removed cavity in boron neutron capture therapy for malignant brain tumours

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Ono, Koji; Miyatake, Shin-ichi; Maruhashi, Akira

    2006-01-01

    Boron neutron capture therapy (BNCT) without craniotomy for malignant brain tumours was started using an epi-thermal neutron beam at the Kyoto University Reactor in June 2002. We have tried some techniques to overcome the treatable-depth limit in BNCT. One of the effective techniques is void formation utilizing a tumour-removed cavity. The tumorous part is removed by craniotomy about 1 week before a BNCT treatment in our protocol. Just before the BNCT irradiation, the cerebro-spinal fluid (CSF) in the tumour-removed cavity is drained out, air is infused to the cavity and then the void is made. This void improves the neutron penetration, and the thermal neutron flux at depth increases. The phantom experiments and survey simulations modelling the CSF drainage and air infusion of the tumour-removed cavity were performed for the size and shape of the void. The advantage of the CSF drainage and air infusion is confirmed for the improvement in the depth-dose distribution. From the parametric surveys, it was confirmed that the cavity volume had good correlation with the improvement effect, and the larger effect was expected as the cavity volume was larger

  14. Improvement effect on the depth-dose distribution by CSF drainage and air infusion of a tumour-removed cavity in boron neutron capture therapy for malignant brain tumours

    Science.gov (United States)

    Sakurai, Yoshinori; Ono, Koji; Miyatake, Shin-ichi; Maruhashi, Akira

    2006-03-01

    Boron neutron capture therapy (BNCT) without craniotomy for malignant brain tumours was started using an epi-thermal neutron beam at the Kyoto University Reactor in June 2002. We have tried some techniques to overcome the treatable-depth limit in BNCT. One of the effective techniques is void formation utilizing a tumour-removed cavity. The tumorous part is removed by craniotomy about 1 week before a BNCT treatment in our protocol. Just before the BNCT irradiation, the cerebro-spinal fluid (CSF) in the tumour-removed cavity is drained out, air is infused to the cavity and then the void is made. This void improves the neutron penetration, and the thermal neutron flux at depth increases. The phantom experiments and survey simulations modelling the CSF drainage and air infusion of the tumour-removed cavity were performed for the size and shape of the void. The advantage of the CSF drainage and air infusion is confirmed for the improvement in the depth-dose distribution. From the parametric surveys, it was confirmed that the cavity volume had good correlation with the improvement effect, and the larger effect was expected as the cavity volume was larger.

  15. Hydrazine and hydrogen coinjection to mitigate stress corrosion cracking of structural materials in boiling water reactors (7). Effects of bulk water chemistry on ECP distribution inside a crack

    International Nuclear Information System (INIS)

    Wada, Yoichi; Ishida, Kazushige; Tachibana, Masahiko; Aizawa, Motohiro; Fuse, Motomasa

    2007-01-01

    Water chemistry in a simulated crack (crack) has been studied to understand the mechanisms of stress corrosion cracking in a boiling water reactor environment. Electrochemical corrosion potential (ECP) in a crack made in an austenite type 304 stainless steel specimen was measured. The ECP distribution along the simulated crack was strongly affected by bulk water chemistry and bulk flow. When oxygen concentration was high in the bulk water, the potential difference between the crack tip and the outside of the crack (ΔE), which must be one motive force for crack growth, was about 0.3V under a stagnant condition. When oxygen was removed from the bulk water, ECP inside and outside the crack became low and uniform and ΔE became small. The outside ECP was also lowered by depositing platinum on the steel specimen surface and adding stoichiometrically excess hydrogen to oxygen to lower ΔE. This was effective only when bulk water did not flow. Under the bulk water flow condition, water-borne oxygen caused an increase in ECP on the untreated surface inside the crack. This also caused a large ΔE. The ΔE effect was confirmed by crack growth rate measurements with a catalyst-treated specimen. Therefore, lowering the bulk oxidant concentration by such measures as hydrazine hydrogen coinjection, which is currently under development, is important for suppressing the crack growth. (author)

  16. The effects of arbuscular mycorrhizal fungi on glomalin-related soil protein distribution, aggregate stability and their relationships with soil properties at different soil depths in lead-zinc contaminated area.

    Directory of Open Access Journals (Sweden)

    Yurong Yang

    Full Text Available Glomalin-related soil protein (GRSP, a widespread glycoprotein produced by arbuscular mycorrhizal fungi (AMF, is crucial for ecosystem functioning and ecological restoration. In the present study, an investigation was conducted to comprehensively analyze the effects of heavy metal (HM contamination on AMF status, soil properties, aggregate distribution and stability, and their correlations at different soil depths (0-10, 10-20, 20-30, 30-40 cm. Our results showed that the mycorrhizal colonization (MC, hyphal length density (HLD, GRSP, soil organic matter (SOM and soil organic carbon (SOC were significantly inhibited by Pb compared to Zn at 0-20 cm soil depth, indicating that HM had significant inhibitory effects on AMF growth and soil properties, and that Pb exhibited greater toxicity than Zn at shallow layer of soil. Both the proportion of soil large macroaggregates (>2000 μm and mean weight diameter (MWD were positively correlated with GRSP, SOM and SOC at 0-20 cm soil depth (P < 0.05, proving the important contributions of GRSP, SOM and SOC for binding soil particles together into large macroaggregates and improving aggregate stability. Furthermore, MC and HLD had significantly positive correlation with GRSP, SOM and SOC, suggesting that AMF played an essential role in GRSP, SOM and SOC accumulation and subsequently influencing aggregate formation and particle-size distribution in HM polluted soils. Our study highlighted that the introduction of indigenous plant associated with AMF might be a successful biotechnological tool to assist the recovery of HM polluted soils, and that proper management practices should be developed to guarantee maximum benefits from plant-AMF symbiosis during ecological restoration.

  17. The effects of arbuscular mycorrhizal fungi on glomalin-related soil protein distribution, aggregate stability and their relationships with soil properties at different soil depths in lead-zinc contaminated area.

    Science.gov (United States)

    Yang, Yurong; He, Chuangjun; Huang, Li; Ban, Yihui; Tang, Ming

    2017-01-01

    Glomalin-related soil protein (GRSP), a widespread glycoprotein produced by arbuscular mycorrhizal fungi (AMF), is crucial for ecosystem functioning and ecological restoration. In the present study, an investigation was conducted to comprehensively analyze the effects of heavy metal (HM) contamination on AMF status, soil properties, aggregate distribution and stability, and their correlations at different soil depths (0-10, 10-20, 20-30, 30-40 cm). Our results showed that the mycorrhizal colonization (MC), hyphal length density (HLD), GRSP, soil organic matter (SOM) and soil organic carbon (SOC) were significantly inhibited by Pb compared to Zn at 0-20 cm soil depth, indicating that HM had significant inhibitory effects on AMF growth and soil properties, and that Pb exhibited greater toxicity than Zn at shallow layer of soil. Both the proportion of soil large macroaggregates (>2000 μm) and mean weight diameter (MWD) were positively correlated with GRSP, SOM and SOC at 0-20 cm soil depth (P soil particles together into large macroaggregates and improving aggregate stability. Furthermore, MC and HLD had significantly positive correlation with GRSP, SOM and SOC, suggesting that AMF played an essential role in GRSP, SOM and SOC accumulation and subsequently influencing aggregate formation and particle-size distribution in HM polluted soils. Our study highlighted that the introduction of indigenous plant associated with AMF might be a successful biotechnological tool to assist the recovery of HM polluted soils, and that proper management practices should be developed to guarantee maximum benefits from plant-AMF symbiosis during ecological restoration.

  18. Hydrogen Special. Facts, developments, opinions

    International Nuclear Information System (INIS)

    Hisschemoeller, M.; Van de Kerkhof, M.; Stam, T.; Cuppen, E.; Bakker, S.; Florisson, O.; Mallant, R.; Ros, J.; Naghelhout, D.; De Witte, N.; Van Delft, J.; Huurman, J.; Susebeek, J.; De Wit, H.; Hogenhuis, C.; Maatman, D.; Vaessen, M.; Vergragt, P.J.; Bout, P.; Molag, M.; Hemmes, K.; Taanman, M.; Dame, E.; Van Soest, J.P.

    2007-01-01

    In a large number of short articles several aspects of hydrogen are discussed: (dis)advantages; production; transport; distribution; storage; use in fuel cells, vehicles and houses; market; financing of the hydrogen-based economy; hydrogen transition and developing countries; education and training; developments in the USA and the European Union [nl

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  20. Electron impact ionization of size selected hydrogen clusters (H2)N: ion fragment and neutral size distributions.

    Science.gov (United States)

    Kornilov, Oleg; Toennies, J Peter

    2008-05-21

    Clusters consisting of normal H2 molecules, produced in a free jet expansion, are size selected by diffraction from a transmission nanograting prior to electron impact ionization. For each neutral cluster (H2)(N) (N=2-40), the relative intensities of the ion fragments Hn+ are measured with a mass spectrometer. H3+ is found to be the most abundant fragment up to N=17. With a further increase in N, the abundances of H3+, H5+, H7+, and H9+ first increase and, after passing through a maximum, approach each other. At N=40, they are about the same and more than a factor of 2 and 3 larger than for H11+ and H13+, respectively. For a given neutral cluster size, the intensities of the ion fragments follow a Poisson distribution. The fragmentation probabilities are used to determine the neutral cluster size distribution produced in the expansion at a source temperature of 30.1 K and a source pressure of 1.50 bar. The distribution shows no clear evidence of a magic number N=13 as predicted by theory and found in experiments with pure para-H2 clusters. The ion fragment distributions are also used to extract information on the internal energy distribution of the H3+ ions produced in the reaction H2+ + H2-->H3+ +H, which is initiated upon ionization of the cluster. The internal energy is assumed to be rapidly equilibrated and to determine the number of molecules subsequently evaporated. The internal energy distribution found in this way is in good agreement with data obtained in an earlier independent merged beam scattering experiment.

  1. Investigation of hydrogen micro-kinetics in metals with ion beam implantation and analysis

    International Nuclear Information System (INIS)

    Wang, T.S.; Peng, H.B.; Lv, H.Y.; Han, Y.C.; Grambole, D.; Herrmann, F.

    2007-01-01

    One of the most important subjects in the fusion material research is to study the hydrogen and helium concentration, diffusion and evolution in the structure material of fusion reactor, since the hydrogen and helium can be continuously produced by the large dose fast neutron irradiation on material. Various analysis Methods can be used, but the ion beam analysis method has some advantages for studying the hydrogen behaviors in nano- or micrometer resolution. In this work, the hydrogen motion and three-dimensional distribution after implantation into metal has been studied by resonance NRA, micro-ERDA and XRD etc Methods. The resolution of the H-depth-profile is in nanometer level and the lateral resolution can be reached to 2 micrometers. The evolution of hydrogen depth-profile in a titanium sample has been studied versus the change of normal stress in samples. Evident hydrogen diffusion has been observed, while a normal stress is changed in the range of 107-963 MPa. A new phase transformation during the hydrogenation is observed by the in-situ XRD analysis. The further study on the hydrogen behaviors in the structure materials of fusion reactor is in plan. (authors)

  2. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

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

  3. Measurements of energy losses, distributions of energy loss and additivity of energy losses for 50 to 150 keV protons in hydrogen and nine hydrocarbon gases

    International Nuclear Information System (INIS)

    Thorngate, J.H.

    1976-05-01

    Measurements of energy-loss distributions were made for 51, 102, and 153 keV protons traversing hydrogen, methane, ethyne (acetylene), ethene (ethylene), ethane, propyne (methyl acetylene), propadiene (allene), propene (propylene), cyclopropane and propane. The objectives were to test the theories of energy-loss distribution in this energy range and to see if the type of carbon bonding in a hydrocarbon molecule affects the shape of the distribution. Stopping powers and stopping cross sections were also measured at these energies and at 76.5 and 127.5 keV to determine effects of chemical binding. All of the measurements were made at the gas density required to give a 4 percent energy loss. The mean energy, second central moment (a measure of the width of the distribution), and the third central moment (a measure of the skew) were calculated from the measured energy-loss distributions. Stopping power values, calculated using the mean energy, compared reasonably well with those calculated from the Bethe stopping power theory. For the second and third central moments, the best agreement between measurement and theory was when the classical scattering probability was used for the calculations, but even these did not agree well. In all cases, variations were found in the data that could be correlated to the type of carbon binding in the molecule. The differences were statistically significant at a 99 percent confidence interval for the stopping powers and second central moments measured with 51 keV protons. Similar trends were noted at other energies and for the third central moment, but the differences were not statistically significant at the 99 percent confidence interval

  4. Online Simulations of Global Aerosol Distributions in the NASA GEOS-4 Model and Comparisons to Satellite and Ground-Based Aerosol Optical Depth

    Science.gov (United States)

    Colarco, Peter; daSilva, Arlindo; Chin, Mian; Diehl, Thomas

    2010-01-01

    We have implemented a module for tropospheric aerosols (GO CART) online in the NASA Goddard Earth Observing System version 4 model and simulated global aerosol distributions for the period 2000-2006. The new online system offers several advantages over the previous offline version, providing a platform for aerosol data assimilation, aerosol-chemistry-climate interaction studies, and short-range chemical weather forecasting and climate prediction. We introduce as well a methodology for sampling model output consistently with satellite aerosol optical thickness (AOT) retrievals to facilitate model-satellite comparison. Our results are similar to the offline GOCART model and to the models participating in the AeroCom intercomparison. The simulated AOT has similar seasonal and regional variability and magnitude to Aerosol Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer, and Multiangle Imaging Spectroradiometer observations. The model AOT and Angstrom parameter are consistently low relative to AERONET in biomass-burning-dominated regions, where emissions appear to be underestimated, consistent with the results of the offline GOCART model. In contrast, the model AOT is biased high in sulfate-dominated regions of North America and Europe. Our model-satellite comparison methodology shows that diurnal variability in aerosol loading is unimportant compared to sampling the model where the satellite has cloud-free observations, particularly in sulfate-dominated regions. Simulated sea salt burden and optical thickness are high by a factor of 2-3 relative to other models, and agreement between model and satellite over-ocean AOT is improved by reducing the model sea salt burden by a factor of 2. The best agreement in both AOT magnitude and variability occurs immediately downwind of the Saharan dust plume.

  5. Hydrogen system (hydrogen fuels feasibility)

    International Nuclear Information System (INIS)

    Guarna, S.

    1991-07-01

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

  6. Spectrometric kidney depth measurement method

    International Nuclear Information System (INIS)

    George, P.; Soussaline, F.; Raynaud, C.

    1976-01-01

    The method proposed uses the single posterior surface measurement of the kidney radioactivity distribution. The ratio C/P of the number of scattered photons to the number of primary photons, which is a function of the tissue depth penetrated, is calculated for a given region. The parameters on which the C/P value depends are determined from studies on phantoms. On the basis of these results the kidney depth was measured on a series of 13 patients and a correlation was established between the value thus calculated and that obtained by the profile method. The reproducibility of the method is satisfactory [fr

  7. Alternatives for hydrogen production in Brazilian regions aiming the generation of distributed electric energy; Alternativas para a producao de hidrogenio nas regioes brasileiras visando a geracao de energia eletrica distribuida

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi Junior, Paulo

    2009-07-01

    In this work possible sources of hydrogen production for the generation of electric energy in a distributed way, with the fuel cell use, had been selected and studied. Three renewable sources (biomass, photovoltaic and wind) have been studied for energy generation in Brazil. For the establishment of numerical values, the main regional agricultural cultures and the amount of biomass in various brazilian states had been evaluated, in the form of waste, capable to be used for future hydrogen production. It was also investigated and evaluated the numerical capacity of hydrogen production from wind and photovoltaic resources for each region in Brazil, considering the electrolytic process. Based on the results, it is possible to demonstrate the potentialities of Brazil for electric energy generation in a planned distributed way, with fossil fuel substitution, and consequently, decreasing the environmental impacts. (author)

  8. Hail hydrogen

    International Nuclear Information System (INIS)

    Hairston, D.

    1996-01-01

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

  9. Penetration of Hydrogen clusters from 10 to 120 kev/u in carbon foils. Study of their slowing-down and charge distribution of emerging fragments

    International Nuclear Information System (INIS)

    Ray, E.M.

    1991-06-01

    This work is devoted to the experimental study of the interaction between fast (10 to 120 keV/p) hydrogen clusters with thin solid targets. First, we have studied the slowing-down of H n + (2≤n≤21) clusters through carbon foils. Up to date this had been made only with molecular ions. We obtain evidence for vicinage effects on the energy loss of proton-clusters. We show that for projectile energies larger than 50 keV/p, the energy loss of a proton in a cluster is enhanced when compared to that of an isolated proton of the same velocity. At lower incident energies, it is a decrease of the energy loss which is observed. The same effect is also observed in the energy lost in the entrance window of a surface barrier detector bombarded by clusters. This phenomenon is interpreted in terms of interferences between individual polarisation wakes induced by each proton of the cluster. In the second part, we propose an accurate method to study the charge state of the atomic fragments resulting from the dissociation of fast H n + (2≤n≤15) clusters through a carbon foil. This method gives also the distribution of the neutral atoms among the emerging fragments. These distributions are finally compared with binomial laws expected from independent particles

  10. Alone in the dark: Distribution, population structure and reproductive mode of the dominant isopod Eurycope spinifrons Gurjanova, 1933 (Isopoda: Asellota: Munnopsidae) from bathyal and abyssal depths of the Sea of Japan

    Science.gov (United States)

    Elsner, Nikolaus O.; Golovan, Olga A.; Malyutina, Marina V.; Brandt, Angelika

    2013-02-01

    Due to isolation and a period of severe anoxic conditions in geologically recent times, biodiversity is low in the deep Sea of Japan. Among a small group of species inhabiting depths below 2500, only one isopod species, Eurycope spinifrons, was found during the SoJaBio expedition in 2010, but it was the most abundant species of all benthic taxa. E. spinifrons was found with remarkably high numbers of individuals at the sampled stations below 2500 m, providing a rare opportunity to investigate aspects of population structure and reproduction of a deep-sea isopod. The distribution, population structure, fecundity and depth dependent density of E. spinifrons were studied. Brooding females were the longest in body size and least abundant, while mancae were the shortest and most abundant. The mean length of individuals showed little deviation among the stations below 2500 m, ranging from 4.21±0.29 mm in brooding females to 1.20±0.26 mm in free-living mancae. Iteroparity is demonstrated for E. spinifrons. It is argued that females have continuous reproduction which increases in the summer. The length of the brooding females is positively correlated with the number of eggs in the marsupium in our sample (r=0.291; p<0.05). Comparing the mean length of E. spinifrons between different stations revealed that specimens sampled at the upper slope (460 m) were significantly smaller in every developmental stage than those from stations below 2500 m. This finding confirms the existence of a threshold depth below which E. spinifrons was the only isopod species found. Thus, we argue that individuals at deeper stations grow bigger due to reduced competition in the deep Sea of Japan.

  11. New hydrogen technologies

    International Nuclear Information System (INIS)

    1992-01-01

    This report presents an overview of the overall hydrogen system. There are separate sections for production, distribution, transport, storage; and applications of hydrogen. The most important methods for hydrogen production are steam reformation of natural gas and electrolysis of water. Of the renewable energy options, production of hydrogen by electrolysis using electricity from wind turbines or by gasification of biomass were found to be the most economic for Finland. Direct use of this electricity or the production of liquid fuels from biomass will be competing alternatives. When hydrogen is produced in the solar belt or where there is cheap hydropower it must be transported over long distances. The overall energy consumed for the transport is from 25 to 40 % of the initial available energy. Hydrogen storage can be divided into stationary and mobile types. The most economic, stationary, large scale hydrogen storage for both long and short periods is underground storage. When suitable sites are not available, then pressure vessels are the best for short period and liquid H 2 for long period. Vehicle storage of hydrogen is by either metal hydrides or liquid H 2 . Hydrogen is a very versatile energy carrier. It can be used to produce heat directly in catalytic burners without flame, to produce electricity in fuel cells with high efficiency for use in vehicles or for peak power shaving, as a fuel component with conventional fuels to reduce emissions, as a way to store energy and as a chemical reagent in reactions

  12. Hydrogen as automotive fuel

    International Nuclear Information System (INIS)

    Dini, D.; Ciancia, A.; Pede, G.; Sglavo, V.; ENEA, Rome

    1992-01-01

    An assessment of the technical/economic feasibility of the use of hydrogen as an automotive fuel is made based on analyses of the following: the chemical- physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems - with water vapour injection, cryogenic injection, and the low or high pressure injection of hydrogen directly into the combustion chamber; the current commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. The paper concludes that, considering current costs for hydrogen fuel production, distribution and use, at present, the employment of hydrogen fuelled vehicles is feasible only in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives

  13. Fiscal 2000 report on the Phase II R and D of the international hydrogen utilization clean energy network system technology (WE-NET). Task 11. Distributed transportation of hydrogen/hydrogen absorbing alloy for hydrogen storage; 2000 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET) dai 2 ki kenkyu kaihatsu seika hokokusho. 11. Suiso bunsan yuso chozoyo suiso kyuzo gokin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Studies were conducted to find out hydrogen absorbing alloys with an effective hydrogen absorption rate of 3 mass % or more, hydrogen discharge temperature of 100 degrees C or lower, hydrogen absorbing capacity after 5,000 cycles not less than 90% of the initial capacity, applicable to stationary and mobile systems. The V-based alloy that achieved an effective hydrogen absorption rate of 2.6 mass % in the preceding fiscal year was subjected to studies relating to safety and durability. Since V is costly, efforts were exerted to develop TiCrMo alloys to replace the V-based alloy. In the search for novel high-performance alloys, endeavors centered on novel ternary alloys, novel alloys based on Mg and Ti, and novel intermetallic compounds of the Mg-4 family. In the study of guidelines for developing next-generation high-performance alloys, methods for creating hydrides with an H/M (hydrogen/metal) ratio far higher than 2 were discussed. Mentioned as techniques to produce such hydrides were the utilization of the hole regulated lattice, novel alloys based on the ultrahigh pressure hydride phase, new substances making use of the cooperative phenomenon in the coexistent multiple-phase structure, and the like. (NEDO)

  14. Characterization of hydrogenated amorphous silicon. Some behaviors of hydrogen and impurities studied by film characterization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Imura, Takeshi; Kubota, Kazuyoshi; Ushita, Katsumi; Hiraki, Akio

    1980-06-01

    Rutherford backscattering spectrometry and infrared absorption measurement were applied to determine composition in hydrogenated amorphous silicon fabricated either by glow discharge in SiH/sub 4/ plus H/sub 2/ or by reactive sputtering in Ar containing H/sub 2/ in a tetrode or diode sputtering apparatus. The atomic density of Si, the content and depth distribution of H, and the amount of impurities such as Ar were studied for the films deposited under several conditions of substrate temperature and gas pressure and constitution. Some difference was clarified between glow-discharge and sputter deposited films.

  15. Hydrogen detector

    International Nuclear Information System (INIS)

    Kumagaya, Hiromichi; Yoshida, Kazuo; Sanada, Kazuo; Chigira, Sadao.

    1994-01-01

    The present invention concerns a hydrogen detector for detecting water-sodium reaction. The hydrogen detector comprises a sensor portion having coiled optical fibers and detects hydrogen on the basis of the increase of light transmission loss upon hydrogen absorption. In the hydrogen detector, optical fibers are wound around and welded to the outer circumference of a quartz rod, as well as the thickness of the clad layer of the optical fiber is reduced by etching. With such procedures, size of the hydrogen detecting sensor portion can be decreased easily. Further, since it can be used at high temperature, diffusion rate is improved to shorten the detection time. (N.H.)

  16. Sensitive and rapid detection of endogenous hydrogen sulfide distributing in different mouse viscera via a two-photon fluorescent probe

    International Nuclear Information System (INIS)

    Chen, Qian; Yang, Jinfeng; Li, Yinhui; Zheng, Jing; Yang, Ronghua

    2015-01-01

    Development of efficient methods for detection of endogenous H 2 S in living cells and tissues is of considerable significance for better understanding the biological and pathological functions of H 2 S. Two-photon (TP) fluorescent probes are favorable as powerful molecular tools for studying physiological process due to its non-invasiveness, high spatiotemporal resolution and deep-tissues imaging. Up to date, several TP probes for intracellular H 2 S imaging have been designed, but real-time imaging of endogenous H 2 S-related biological processes in tissues is hampered due to low sensitivity, long response time and interference from other biothiols. To address this issue, we herein report a novel two-photon fluorescent probe (TPP-H 2 S) for highly sensitive and fast monitoring and imaging H 2 S levels in living cells and tissues. In the presence of H 2 S, it exhibits obviously improved sensitivity (LOD: 0.12 μM) and fast response time (about 2 min) compared with the reported two-photon H 2 S probes. With two-photon excitation, TPP-H 2 S displays high signal-to-noise ratio and sensitivity even no interference in cell growth media. As further application, TPP-H 2 S is applied for fast imaging of H 2 S in living cells and different fresh tissues by two-photon confocal microscope. Most importantly we first measured the endogenous H 2 S level in different viscera by vivisection and found that the distribution of endogenous H 2 S mostly in brain, liver and lung. The excellent sensing properties of TPP-H 2 S make it a practically useful tool for further studying biological roles of H 2 S. - Highlights: • This two-photon probe exhibits an improved sensitivity and response time to H 2 S. • This probe shows excellent membrane permeability and fast visualization of H 2 S in living cells and tissues. • This probe is successfully applied to measure the endogenously produced H 2 S levels in different viscera of mouse.

  17. Phase and ellipticity dependence of the photoelectron angular distribution in non-resonant two-photon ionization of atomic hydrogen. I

    Energy Technology Data Exchange (ETDEWEB)

    Faye, M; Wane, S T, E-mail: mamadou.faye@ucad.edu.sn [Departement de Physique, Faculte des Sciences et Techniques, Universite Cheikh Anta Diop, Boulevard Martin Luther King, (Corniche Ouest) BP 5005-Dakar Fann (Senegal)

    2011-03-14

    We study the ellipticity and the dependence on the phase lag (lead) (between the semimajor and the semiminor axes of the field components) of the photoelectron angular distribution (PAD) in the non-resonant two-photon ionization of atomic hydrogen. We establish exact analytical expressions for azimuthal PAD for 3s, 3p and 3d excited initial states, marked by the occurrence of an asymmetric term. This term gives rise to elliptic dichroism (ED), which can be obtained in two ways: either with the left (versus right) ellipticity, or with the phase lag (versus lead); for 3s and 3p initial states, it is shown that the quantum phase of continua is directly related to the phase lag, one-photon below-threshold ionization, and indirectly one photon above. Another important result is that the magnetic sublevels, m = 0, for 3p and m = {+-}1, for 3d, do not contribute to the azimuthal PAD. Our numerical results show, for 3s and 3d, and near-threshold ionization, that the PAD has maxima either along the semimajor or the semiminor axis, while for above-threshold ionization, they are always shifted from these axes. However, the maxima of the corresponding ED coincide with the PAD maxima, while for 3p, they are shifted from the PAD minima. A strong dependence of the ED sign is noted, regardless of the state or the process. However, strong ED signals are obtained for the 3s initial state and below-threshold ionization.

  18. Hydrogen highway

    International Nuclear Information System (INIS)

    Anon

    2008-01-01

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

  19. Distribution

    Science.gov (United States)

    John R. Jones

    1985-01-01

    Quaking aspen is the most widely distributed native North American tree species (Little 1971, Sargent 1890). It grows in a great diversity of regions, environments, and communities (Harshberger 1911). Only one deciduous tree species in the world, the closely related Eurasian aspen (Populus tremula), has a wider range (Weigle and Frothingham 1911)....

  20. Potential for post-closure radionuclide redistribution due to biotic intrusion: aboveground biomass, litter production rates, and the distribution of root mass with depth at material disposal area G, Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    French, Sean B.; Christensen, Candace; Jennings, Terry L.; Jaros, Christopher L.; Wykoff, David S.; Crowell, Kelly J.; Shuman, Rob

    2008-01-01

    Low-level radioactive waste (LLW) generated at the Los Alamos National Laboratories (LANL) is disposed of at LANL's Technical Area (T A) 54, Material Disposal Area (MDA) G. The ability of MDA G to safely contain radioactive waste during current and post-closure operations is evaluated as part of the facility's ongoing performance assessment (PA) and composite analysis (CA). Due to the potential for uptake and incorporation of radio nuclides into aboveground plant material, the PA and CA project that plant roots penetrating into buried waste may lead to releases of radionuclides into the accessible environment. The potential amount ofcontamination deposited on the ground surface due to plant intrusion into buried waste is a function of the quantity of litter generated by plants, as well as radionuclide concentrations within the litter. Radionuclide concentrations in plant litter is dependent on the distribution of root mass with depth and the efficiency with which radionuclides are extracted from contaminated soils by the plant's roots. In order to reduce uncertainties associated with the PA and CA for MDA G, surveys are being conducted to assess aboveground biomass, plant litter production rates, and root mass with depth for the four prominent vegetation types (grasses, forbs, shrubs and trees). The collection of aboveground biomass for grasses and forbs began in 2007. Additional sampling was conducted in October 2008 to measure root mass with depth and to collect additional aboveground biomass data for the types of grasses, forbs, shrubs, and trees that may become established at MDA G after the facility undergoes final closure, Biomass data will be used to estimate the future potential mass of contaminated plant litter fall, which could act as a latent conduit for radionuclide transport from the closed disposal area. Data collected are expected to reduce uncertainties associated with the PA and CA for MDA G and ultimately aid in the assessment and subsequent

  1. Hydrogen problems in reactor safety research

    International Nuclear Information System (INIS)

    Casper, H.

    1984-01-01

    The BMFT and BMI have initiated a workshop 'Hydrogen Problems in Reactor Safety Research' that took place October 3./4., 1983. The objective of this workshop was to present the state of the art in the main areas - Hydrogen-Production - Hydrogen-Distribution - Hydrogen-Ignition - Hydrogen-Burning and Containment Behaviour - Mitigation Measures. The lectures on the different areas are compiled. The most important results of the final discussion are summarized as well. (orig.) [de

  2. Complexity and Dynamical Depth

    Directory of Open Access Journals (Sweden)

    Terrence Deacon

    2014-07-01

    Full Text Available We argue that a critical difference distinguishing machines from organisms and computers from brains is not complexity in a structural sense, but a difference in dynamical organization that is not well accounted for by current complexity measures. We propose a measure of the complexity of a system that is largely orthogonal to computational, information theoretic, or thermodynamic conceptions of structural complexity. What we call a system’s dynamical depth is a separate dimension of system complexity that measures the degree to which it exhibits discrete levels of nonlinear dynamical organization in which successive levels are distinguished by local entropy reduction and constraint generation. A system with greater dynamical depth than another consists of a greater number of such nested dynamical levels. Thus, a mechanical or linear thermodynamic system has less dynamical depth than an inorganic self-organized system, which has less dynamical depth than a living system. Including an assessment of dynamical depth can provide a more precise and systematic account of the fundamental difference between inorganic systems (low dynamical depth and living systems (high dynamical depth, irrespective of the number of their parts and the causal relations between them.

  3. Hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Pahwa, P.K.; Pahwa, Gulshan Kumar

    2013-10-01

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

  4. Motivation with Depth.

    Science.gov (United States)

    DiSpezio, Michael A.

    2000-01-01

    Presents an illusional arena by offering experience in optical illusions in which students must apply critical analysis to their innate information gathering systems. Introduces different types of depth illusions for students to experience. (ASK)

  5. Hydrogen energy and sustainability: overview and the role for nuclear energy

    International Nuclear Information System (INIS)

    Rosen, M.A.

    2008-01-01

    This paper discusses the role of nuclear power in hydrogen energy and sustainability. Hydrogen economy is based on hydrogen production, packaging (compression, liquefaction, hydrides), distribution (pipelines, road, rail, ship), storage (pressure and cryogenic containers), transfer and finally hydrogen use

  6. Ion beam analysis of hydrogen retained in carbon nanotubes and carbon films

    International Nuclear Information System (INIS)

    McDaniel, F.D.; Holland, O.W.; Naab, F.U.; Mitchell, L.J.; Dhoubhadel, M.; Duggan, J.L.

    2006-01-01

    Carbon nanotubes (CNTs) are studied as a possible hydrogen storage medium for future energy needs. Typically, hydrogen is stored in the CNTs by exposure of the material to a high-pressure H 2 atmosphere at different temperatures. The maximum hydrogen concentrations stored following this method and measured using ion beam analysis do not exceed 1 wt.%. Introduction of defects by ion irradiation (i.e. implantation) prior to high-pressure H 2 treatment, offers an alternative method to activate H adsorption and enhance the chemisorption of hydrogen. This is a preliminary work where hydrogen was introduced into single-wall nanotubes and carbon films by low-energy (13.6 keV) hydrogen ion implantation. Elastic recoil detection was used to measure the quantity and depth distribution of hydrogen retained in the carbonaceous materials. Results show that there are substantial differences in the measured profiles between the CNT samples and the vitreous carbon. On another hand, only ∼43% of the implanted hydrogen in the CNTs is retained in the region where it should be located according to the SRIM simulations for a solid carbon sample

  7. The hydrogen issue.

    Science.gov (United States)

    Armaroli, Nicola; Balzani, Vincenzo

    2011-01-17

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

  8. Development of micro-beam NRA for 3D-mapping of hydrogen distribution in solids: Application of tapered glass capillary to 6 MeV 15N ion

    International Nuclear Information System (INIS)

    Sekiba, D.; Yonemura, H.; Nebiki, T.; Wilde, M.; Ogura, S.; Yamashita, H.; Matsumoto, M.; Kasagi, J.; Iwamura, Y.; Itoh, T.; Matsuzaki, H.; Narusawa, T.; Fukutani, K.

    2008-01-01

    A micro-beam NRA system, by means of a resonant nuclear reaction 1 H( 15 N, αγ) 12 C, has been developed for the purpose of the 3D mapping of the hydrogen distribution in solids. To obtain the tens μm size of the beam spot, the combination of the newly proposed tapered glass capillary and a conventional quadrupole magnetic lens is employed. An Y patterned film on a substrate is prepared as an application of the developed system. The 6 MeV 15 N beam focused by glass capillaries down to 50 μm successfully shows the hydrogen distribution. The in-plane NRA profile implies that the beam emitted from the glass capillary outlet is parallel, although the original beam has a considerable divergence. The NRA measurements in the 10 3 Pa N 2 atmosphere due to the low gas conductance of the glass capillary is also demonstrated

  9. Phase and ellipticity dependence of the photoelectron angular distribution in non-resonant two-photon ionization of atomic hydrogen. I

    International Nuclear Information System (INIS)

    Faye, M; Wane, S T

    2011-01-01

    We study the ellipticity and the dependence on the phase lag (lead) (between the semimajor and the semiminor axes of the field components) of the photoelectron angular distribution (PAD) in the non-resonant two-photon ionization of atomic hydrogen. We establish exact analytical expressions for azimuthal PAD for 3s, 3p and 3d excited initial states, marked by the occurrence of an asymmetric term. This term gives rise to elliptic dichroism (ED), which can be obtained in two ways: either with the left (versus right) ellipticity, or with the phase lag (versus lead); for 3s and 3p initial states, it is shown that the quantum phase of continua is directly related to the phase lag, one-photon below-threshold ionization, and indirectly one photon above. Another important result is that the magnetic sublevels, m = 0, for 3p and m = ±1, for 3d, do not contribute to the azimuthal PAD. Our numerical results show, for 3s and 3d, and near-threshold ionization, that the PAD has maxima either along the semimajor or the semiminor axis, while for above-threshold ionization, they are always shifted from these axes. However, the maxima of the corresponding ED coincide with the PAD maxima, while for 3p, they are shifted from the PAD minima. A strong dependence of the ED sign is noted, regardless of the state or the process. However, strong ED signals are obtained for the 3s initial state and below-threshold ionization.

  10. Assessment for ion beam analysis methods about hydrogen isotope in hydrogen storaged metal

    International Nuclear Information System (INIS)

    Ding Wei; Long Xinggui; Shi Liqun

    2006-01-01

    In this paper, experimental arrangements of measuring hydrogen isotope concentration and distribution in metal hydride with ion beam analysis methods were reported, and the advantage and disadvantage of different methods were analyzed too. Experiment results show that it can get abundant information and accurate value by these ways. It can get an accurate value since it's the Rutherford cross-section, and the Mylar film used in the experiment is thin enough for H, D and T distinguishing each other while using ERD analysis method with 6.0 MeV O ion beam to proceed this work, but the disadvantage of this method is that the sample preparing is more difficult, and the analysis depth is lower. It could get the distribution information of H, D and T and the analysis depth is about 3.0 μm while using ERD analysis method with 7.4 MeV 4 He ion beam, but the disadvantage is that the spectra of H, D and T overlap each other, which makes a big error in simulated calculation. If using PBS method with 3.0 MeV proton, the analysis depth is deeper, but it couldn't get the H distribution information. (authors)

  11. Hydrogen safety

    International Nuclear Information System (INIS)

    Frazier, W.R.

    1991-01-01

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

  12. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

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

  13. MOPABA-H2 - Computer code for calculation of hydrogen generation and distribution in the equipment of power plants with WWER type reactors in design modes of operation

    International Nuclear Information System (INIS)

    Arkhipov, O.P.; Kharitonov, Yu.V.; Shumskiy, A.M.; Kabakchi, S.A.

    2002-01-01

    With the aim of ensuring the hydrogen explosive-proof situation in the reactor plant, a complex of scientific-and-research work was carried out including the following: revealing the mechanisms of generation and release of hydrogen in the primary equipment components under design operation modes of the reactor plant with WWER; development of calculation procedure and computer code MOPABA-H2 enabling to determine the hydrogen content in RP equipment components under design operation modes. In the process of procedure development it was found out that the calculation of hydrogen content in the plant equipment requires development of the following main mathematical models: radiochemical processes in the primary coolant which has impurities and added special reagents; absorption of the core ionizing radiation by the coolant; steam-zirconium reaction (during design-basis accident of LOCA type); coolant mass transfer over the reactor plant equipment including transition of the phase boundary by the components of the coolant. (author)

  14. Prestack depth migration

    International Nuclear Information System (INIS)

    Postma, R.W.

    1991-01-01

    Two lines form the southern North Sea, with known velocity inhomogeneities in the overburden, have been pre-stack depth migrated. The pre-stack depth migrations are compared with conventional processing, one with severe distortions and one with subtle distortions on the conventionally processed sections. The line with subtle distortions is also compared with post-stack depth migration. The results on both lines were very successful. Both have already influenced drilling decisions, and have caused a modification of structural interpretation in the respective areas. Wells have been drilled on each of the lines, and well tops confirm the results. In fact, conventional processing led to incorrect locations for the wells, both of which were dry holes. The depth migrated sections indicate the incorrect placement, and on one line reveals a much better drilling location. This paper reports that even though processing costs are high for pre-stack depth migration, appropriate use can save millions of dollars in dry-hole expense

  15. Quantification of the distribution of hydrogen by nuclear microprobe at the Laboratory Pierre Sue in the width of zirconium alloy fuel clad of PWR reactors; Quantification de la repartition de l'hydrogene a la microsonde nucleaire du Laboratoire Pierre Sue dans l'epaisseur de tubes de gainage du combustible des REP en alliage de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Raepsaet, C. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules (DSM/DRECAM/LPS-CNRS) UMR9956, 91 - Gif sur Yvette (France); Bossis, Ph. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SEMULM2E), 91 - Gif-sur-Yvette (France); Hamon, D.; Bechade, J.L.; Brachet, J.C. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMALA2M), 91 - Gif-sur-Yvette (France)

    2007-07-01

    Among the analysis techniques by ions beams, the micro ERDA (Elastic Detection Analysis) is an interesting technique which allows the quantitative distribution of the hydrogen in materials. In particular, this analysis has been used for hydride zirconium alloys, with the nuclear microprobe of the Laboratory Pierre Sue. This probe allows the characterization of radioactive materials. The technique principles are recalled and then two examples are provided to illustrate the fuel clad behavior in PWR reactors. (A.L.B.)

  16. Hydrogen millennium

    International Nuclear Information System (INIS)

    Bose, T.K.; Benard, P.

    2000-05-01

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

  17. Radon depth migration

    International Nuclear Information System (INIS)

    Hildebrand, S.T.; Carroll, R.J.

    1993-01-01

    A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

  18. Measuring depth in boreholes

    International Nuclear Information System (INIS)

    Hodson, G.M.

    1979-01-01

    This invention relates to a method of determining the depth of rock strata and other features of a borehole. It may be employed with particular advantage when access to the top of the borehole is difficult, for example in underwater operations. A radioactive marker, such as a source of gamma rays, is positioned near the top of the riser of a sub-sea wellhead structure. A radiation detector is lowered between the marker and a radioactive stratum and the length of line supplied is measured on the floating platform. This enables the depth of the stratum to be measured irrespective of tidal variations of the height of the platform. (U.K.)

  19. Why bother about depth?

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Obrador, Biel; Christensen, Jesper Philip

    We present results from a newly developed method to determine depth specific rates of GPP, NEP and R using frequent automated profiles of DO and temperature. Metabolic rate calculations were made for three lakes of different trophic status using a diel DO methodology that integrates rates across...

  20. Defining depth of anesthesia.

    Science.gov (United States)

    Shafer, S L; Stanski, D R

    2008-01-01

    In this chapter, drawn largely from the synthesis of material that we first presented in the sixth edition of Miller's Anesthesia, Chap 31 (Stanski and Shafer 2005; used by permission of the publisher), we have defined anesthetic depth as the probability of non-response to stimulation, calibrated against the strength of the stimulus, the difficulty of suppressing the response, and the drug-induced probability of non-responsiveness at defined effect site concentrations. This definition requires measurement of multiple different stimuli and responses at well-defined drug concentrations. There is no one stimulus and response measurement that will capture depth of anesthesia in a clinically or scientifically meaningful manner. The "clinical art" of anesthesia requires calibration of these observations of stimuli and responses (verbal responses, movement, tachycardia) against the dose and concentration of anesthetic drugs used to reduce the probability of response, constantly adjusting the administered dose to achieve the desired anesthetic depth. In our definition of "depth of anesthesia" we define the need for two components to create the anesthetic state: hypnosis created with drugs such as propofol or the inhalational anesthetics and analgesia created with the opioids or nitrous oxide. We demonstrate the scientific evidence that profound degrees of hypnosis in the absence of analgesia will not prevent the hemodynamic responses to profoundly noxious stimuli. Also, profound degrees of analgesia do not guarantee unconsciousness. However, the combination of hypnosis and analgesia suppresses hemodynamic response to noxious stimuli and guarantees unconsciousness.

  1. Depth resolved investigations of boron implanted silicon

    Science.gov (United States)

    Sztucki, M.; Metzger, T. H.; Milita, S.; Berberich, F.; Schell, N.; Rouvière, J. L.; Patel, J.

    2003-01-01

    We have studied the depth distribution and structure of defects in boron implanted silicon (0 0 1). Silicon wafers were implanted with a boron dose of 6×10 15 ions/cm -2 at 32 keV and went through different annealing treatments. Using diffuse X-ray scattering at grazing incidence and exit angles we are able to distinguish between different kinds of defects (point defect clusters and extrinsic stacking faults on {1 1 1} planes) and to determine their depth distribution as a function of the thermal budget. Cross-section transmission electron microscopy was used to gain complementary information. In addition we have determined the strain distribution caused by the boron implantation as a function of depth from rocking curve measurements.

  2. Hydrogen energy stations: along the roadside to the hydrogen economy

    International Nuclear Information System (INIS)

    Clark, W.W.; Rifkin, J.; O'Connor, T.; Swisher, J.; Lipman, T.; Rambach, G.

    2005-01-01

    Hydrogen has become more than an international topic of discussion within government and among industry. With the public announcements from the European Union and American governments and an Executive Order from the Governor of California, hydrogen has become a ''paradigm change'' targeted toward changing decades of economic and societal behaviours. The public demand for clean and green energy as well as being ''independent'' or not located in political or societal conflict areas, has become paramount. The key issues are the commitment of governments through public policies along with corporations. Above all, secondly, the advancement of hydrogen is regional as it depends upon infrastructure and fuel resources. Hence, the hydrogen economy, to which the hydrogen highway is the main component, will be regional and creative. New jobs, businesses and opportunities are already emerging. And finally, the costs for the hydrogen economy are critical. The debate as to hydrogen being 5 years away from being commercial and available in the marketplace versus needing more research and development contradicts the historical development and deployment of any new technology be it bio-science, flat panel displays, computers or mobile phones. The market drivers are government regulations and standards soon thereafter matched by market forces and mass production. Hydrogen is no different. What this paper does is describes is how the hydrogen highway is the backbone to the hydrogen economy by becoming, with the next five years, both regional and commercial through supplying stationary power to communities. Soon thereafter, within five to ten years, these same hydrogen stations will be serving hundreds and then thousands of hydrogen fuel powered vehicles. Hydrogen is the fuel for distributed energy generation and hence positively impacts the future of public and private power generators. The paradigm has already changed. (author)

  3. A 4-D Climatology (1979-2009) of the Monthly Tropospheric Aerosol Optical Depth Distribution over the Mediterranean Region from a Comparative Evaluation and Blending of Remote Sensing and Model Products

    Science.gov (United States)

    Nabat, P.; Somot, S.; Mallet, M.; Chiapello, I; Morcrette, J. J.; Solomon, F.; Szopa, S.; Dulac, F; Collins, W.; Ghan, S.; hide

    2013-01-01

    Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD) over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multiyear database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, seasalt, sulfate, black and organic carbon). We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products), TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth- Probe) and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997), the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level- 2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA) has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer), and sulfate aerosols over continental Europe (summer). The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products). Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between dust

  4. A 4-D climatology (1979–2009 of the monthly tropospheric aerosol optical depth distribution over the Mediterranean region from a comparative evaluation and blending of remote sensing and model products

    Directory of Open Access Journals (Sweden)

    P. Nabat

    2013-05-01

    Full Text Available Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multi-year database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, sea-salt, sulfate, black and organic carbon. We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products, TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth-Probe and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997, the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level-2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer, and sulfate aerosols over continental Europe (summer. The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products. Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between

  5. Hydrogen, nitrogen and syngas enriched diesel combustion

    OpenAIRE

    Christodoulou, Fanos

    2014-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University On-board hydrogen and syngas production is considered as a transition solution from fossil fuel to hydrogen powered vehicles until problems associated with hydrogen infrastructure, distribution and storage are resolved. A hydrogen- or syngas-rich stream, which substitutes part of the main hydrocarbon fuel, can be produced by supplying diesel fuel in a fuel-reforming reactor, integrated within ...

  6. Measurement of light-atom distributions in solids

    International Nuclear Information System (INIS)

    Blewer, R.S.

    1977-01-01

    We have developed a sensitive technique that is capable of nondestructively measuring the abundance and depth-distribution of isotopes of hydrogen or helium imbedded in a solid. The measurement is a form of ion-backscattering spectrometry which uses protons to probe within approximately 10μm of the surface of a solid. By analyzing the energy of the backscattered protons we can determine the number of atoms of a given mass present at various depths in the target material. This method permits detection of the lightest elements (i.e., those most difficult to detect by conventional ion-backscattering spectrometry) without sacrificing the capability of revealing the abundance and depth-distribution of heavier elements. For example, we have measured the initial distribution of helium implanted in a metal, then in subsequent measurements kept track of the helium migration

  7. Questioning hydrogen

    International Nuclear Information System (INIS)

    Hammerschlag, Roel; Mazza, Patrick

    2005-01-01

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

  8. Ionization of Interstellar Hydrogen

    Science.gov (United States)

    Whang, Y. C.

    1996-09-01

    Interstellar hydrogen can penetrate through the heliopause, enter the heliosphere, and may become ionized by photoionization and by charge exchange with solar wind protons. A fluid model is introduced to study the flow of interstellar hydrogen in the heliosphere. The flow is governed by moment equations obtained from integration of the Boltzmann equation over the velocity space. Under the assumption that the flow is steady axisymmetric and the pressure is isotropic, we develop a method of solution for this fluid model. This model and the method of solution can be used to study the flow of neutral hydrogen with various forms of ionization rate β and boundary conditions for the flow on the upwind side. We study the solution of a special case in which the ionization rate β is inversely proportional to R2 and the interstellar hydrogen flow is uniform at infinity on the upwind side. We solve the moment equations directly for the normalized density NH/NN∞, bulk velocity VH/VN∞, and temperature TH/TN∞ of interstellar hydrogen as functions of r/λ and z/λ, where λ is the ionization scale length. The solution is compared with the kinetic theory solution of Lallement et al. The fluid solution is much less time-consuming than the kinetic theory solutions. Since the ionization rate for production of pickup protons is directly proportional to the local density of neutral hydrogen, the high-resolution solution of interstellar neutral hydrogen obtained here will be used to study the global distribution of pickup protons.

  9. Hydrologic controls on equilibrium soil depths

    Science.gov (United States)

    Nicótina, L.; Tarboton, D. G.; Tesfa, T. K.; Rinaldo, A.

    2011-04-01

    This paper deals with modeling the mutual feedbacks between runoff production and geomorphological processes and attributes that lead to patterns of equilibrium soil depth. Our primary goal is an attempt to describe spatial patterns of soil depth resulting from long-term interactions between hydrologic forcings and soil production, erosion, and sediment transport processes under the framework of landscape dynamic equilibrium. Another goal is to set the premises for exploiting the role of soil depths in shaping the hydrologic response of a catchment. The relevance of the study stems from the massive improvement in hydrologic predictions for ungauged basins that would be achieved by using directly soil depths derived from geomorphic features remotely measured and objectively manipulated. Hydrological processes are here described by explicitly accounting for local soil depths and detailed catchment topography. Geomorphological processes are described by means of well-studied geomorphic transport laws. The modeling approach is applied to the semiarid Dry Creek Experimental Watershed, located near Boise, Idaho. Modeled soil depths are compared with field data obtained from an extensive survey of the catchment. Our results show the ability of the model to describe properly the mean soil depth and the broad features of the distribution of measured data. However, local comparisons show significant scatter whose origins are discussed.

  10. Hydrogen Contamination of Niobium Surfaces

    International Nuclear Information System (INIS)

    Viet Nguyen-Tuong; Lawrence Doolittle

    1993-01-01

    The presence of hydrogen is blamed for dramatic reductions in cavity Q's. Hydrogen concentration is difficult to measure, so there is a great deal of Fear, Uncertainty, and Doubt (FUD) associated with the problem. This paper presents measurements of hydrogen concentration depth profiles, commenting on the pitfalls of the methods used and exploring how material handling can change the amount of hydrogen in pieces of niobium. Hydrogen analysis was performed by a forward scattering experiment with Helium used as the primary beam. This technique is variously known as FRES (Forward Recoil Elastic Scattering), FRS, HFS (Hydrogen Forward Scattering), and HRA (Hydrogen Recoil Analysis). Some measurements were also made using SIMS (Secondary Ion Mass Spectrometry). Both HFS and SIMS are capable of measuring a depth profile of Hydrogen. The primary difficulty in interpreting the results from these techniques is the presence of a surface peak which is due (at least in part) to contamination with either water or hydrocarbons. With HFS, the depth resolution is about 30 nm, and the maximum depth profiled is about 300 nm. (This 10-1 ratio is unusually low for ion beam techniques, and is a consequence of the compromises that must be made in the geometry of the experiment, surface roughness, and energy straggling in the absorber foil that must be used to filter out the forward scattered helium.) All the observed HFS spectra include a surface peak which includes both surface contamination and any real hydrogen uptake by the niobium surface. Some contamination occurs during the analysis. The vacuum in the analysis chamber is typically a few times 10(sup -6) torr, and some of the contamination is in the form of hydrocarbons from the pumping system. Hydrocarbons normally form a very thin (less than a monolayer) film which is in equilibrium between arrival rate and the evaporation rate. In the presence of the incoming ion beam, however, these hydrocarbons crack on the surface into non

  11. Hydrogen analysis by elastic recoil spectrometry

    International Nuclear Information System (INIS)

    Tirira, J.; Trocellier, P.

    1989-01-01

    An absolute, quantitative procedure was developed to determine the hydrogen content and to describe its concentration profile in the near-surface region of solids. The experimental technique used was the elastic recoil detection analysis of protons induced by 4 He beam bombardment in the energy range <=1.8 MeV. The hydrogen content was calculated using a new recoil cross section expression. The analyses were performed in silicon crystals implanted with hydrogen at 10 keV. The implantation dose was evaluated with an accuracy of 10% and the hydrogen depth profile with that of +-10 nm around 200 nm. (author) 10 refs.; 3 figs

  12. Hydrogen can be used as a perfect fuel

    International Nuclear Information System (INIS)

    Aydin, E.

    2005-01-01

    At present, hydrogen is one of the new and clean energy production sources. Hydrogen is the perfect partner for electricity, and together they create an integrated energy system based on distributed power generation and use. Hydrogen and electricity are interchangeable using a fuel cell (to convert hydrogen to electricity) or an electrolyzer (for converting electricity to hydrogen). A regenerative fuel cell works either way, converting hydrogen to electricity and vice versa. Hydrogen and electricity are both energy carriers because, unlike naturally occurring hydrocarbon fuels, they must both be produced using a primary energy source. In this study, it will be discussed whether hydrogen is perfect fuel or not

  13. Shave-off depth profiling: Depth profiling with an absolute depth scale

    International Nuclear Information System (INIS)

    Nojima, M.; Maekawa, A.; Yamamoto, T.; Tomiyasu, B.; Sakamoto, T.; Owari, M.; Nihei, Y.

    2006-01-01

    Shave-off depth profiling provides profiling with an absolute depth scale. This method uses a focused ion beam (FIB) micro-machining process to provide the depth profile. We show that the shave-off depth profile of a particle reflected the spherical shape of the sample and signal intensities had no relationship to the depth. Through the introduction of FIB micro-sampling, the shave-off depth profiling of a dynamic random access memory (DRAM) tip was carried out. The shave-off profile agreed with a blue print from the manufacturing process. Finally, shave-off depth profiling is discussed with respect to resolutions and future directions

  14. Hydrogen program overview

    Energy Technology Data Exchange (ETDEWEB)

    Gronich, S. [Dept. of Energy, Washington, DC (United States). Office of Utility Technologies

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  15. Passive Wireless Hydrogen Sensors Using Orthogonal Frequency Coded Acoustic Wave Devices, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) based hydrogen sensors for NASA application to distributed wireless hydrogen leak...

  16. Multiple scattering effects in depth resolution of elastic recoil detection

    International Nuclear Information System (INIS)

    Wielunski, L.S.; Harding, G.L.

    1998-01-01

    Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors)

  17. Multiple scattering effects in depth resolution of elastic recoil detection

    Energy Technology Data Exchange (ETDEWEB)

    Wielunski, L.S.; Harding, G.L. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Telecommunications and Industrial Physics; Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, Budapest, (Hungary)

    1998-06-01

    Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors). 19 refs., 4 figs.

  18. Silicon surface damage caused by reactive ion etching in fluorocarbon gas mixtures containing hydrogen

    International Nuclear Information System (INIS)

    Norstroem, H.; Blom, H.; Ostling, M.; Nylandsted Larsen, A.; Keinonen, J.; Berg, S.

    1991-01-01

    For selective etching of SiO 2 on silicon, gases or gas mixtures containing hydrogen are often used. Hydrogen from the glow discharge promotes the formation of a thin film polymer layer responsible for the selectivity of the etching process. The reactive ion etch (RIE) process is known to create damage in the silicon substrate. The influence of hydrogen on the damage and deactivation of dopants is investigated in the present work. The distribution of hydrogen in silicon, after different etching and annealing conditions have been studied. The influence of the RIE process on the charge carrier concentration in silicon has been investigated. Various analytical techniques like contact resistivity measurements, four point probe measurements, and Hall measurements have been used to determine the influence of the RIE process on the electrical properties of processed silicon wafers. The hydrogen profile in as-etched and post annealed wafers was determined by the 1 H( 15 N,αγ) 12 C nuclear reaction. The depth of the deactivated surface layer is discussed in terms of the impinging hydrogen ion energy, i.e., the possibility of H + ions to pick up an energy equal to the peak-to-peak voltage of the rf signal

  19. Hydrogen: Fueling the Future

    International Nuclear Information System (INIS)

    Leisch, Jennifer

    2007-01-01

    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

  20. Institutional Strength in Depth

    International Nuclear Information System (INIS)

    Weightman, M.

    2016-01-01

    Much work has been undertaken in order to identify, learn and implement the lessons from the TEPCO Fukushima Daiichi nuclear accident. These have mainly targeted on engineering or operational lessons. Less attention has been paid to the institutional lessons, although there have been some measures to improve individual peer reviews, particularly by the World Association of Nuclear Operators, and the authoritative IAEA report published in 2015 brought forward several important lessons for regulators and advocated a system approach. The report noted that one of the contributing factors the accident was the tendency of stakeholders not to challenge. Additionally, it reported deficiencies in the regulatory authority and system. Earlier, the root cause of the accident was identified by a Japanese independent parliamentary report as being cultural and institutional. The sum total of the institutions, the safety system, was ineffective. While it is important to address the many technical and operational lessons these may not necessary address this more fundamental lesson, and may not serve to provide robust defences against human or institutional failings over a wide variety of possible events and combinations. The overall lesson is that we can have rigorous and comprehensive safety standards and other tools in place to deliver high levels of safety, but ultimately what is important is the ability of the nuclear safety system to ensure that the relevant institutions diligently and effectively apply those standards and tools — to be robust and resilient. This has led to the consideration of applying the principles of the strength in depth philosophy to a nuclear safety system as a way of providing a framework for developing, assessing, reviewing and improving the system. At an IAEA conference in October 2013, a model was presented for a robust national nuclear safety system based on strength in depth philosophy. The model highlighted three main layers: industry, the

  1. Optical Fiber Grating Hydrogen Sensors: A Review.

    Science.gov (United States)

    Dai, Jixiang; Zhu, Li; Wang, Gaopeng; Xiang, Feng; Qin, Yuhuan; Wang, Min; Yang, Minghong

    2017-03-12

    In terms of hydrogen sensing and detection, optical fiber hydrogen sensors have been a research issue due to their intrinsic safety and good anti-electromagnetic interference. Among these sensors, hydrogen sensors consisting of fiber grating coated with sensitive materials have attracted intensive research interests due to their good reliability and distributed measurements. This review paper mainly focuses on optical fiber hydrogen sensors associated with fiber gratings and various materials. Their configurations and sensing performances proposed by different groups worldwide are reviewed, compared and discussed in this paper. Meanwhile, the challenges for fiber grating hydrogen sensors are also addressed.

  2. Offshore Wind Technology Depth Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coastal bathymetric depth, measured in meters at depth values of: -30, -60, -900 Shallow Zone (0-30m): Technology has been demonstrated on a commercial scale at...

  3. Depth resolution of secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Pustovit, A.N.

    2004-01-01

    The effect of the solid body discreteness in the direction of the normal to the sample surface on the depth resolution of the secondary ion mass spectrometry method is analyzed. It is shown that for this case the dependence of the width at the semi-height of the delta profiles of the studied elements depth distribution on the energy and angle of incidence of the initial ions should have the form of the stepwise function. This is experimentally proved by the silicon-germanium delta-layers in the silicon samples [ru

  4. Metastable hydrogen

    International Nuclear Information System (INIS)

    Dose, V.

    1982-01-01

    This paper deals with the basic physical properties of the metastable 2 2 sub(1/2) state of atomic hydrogen. Applications relying on its special properties, including measurement of the Lamb shift, production of spin-polarized protons and the measurement of molecular electric moments, are discussed. (author)

  5. Seed drill instrumentation for spatial coulter depth measurements

    DEFF Research Database (Denmark)

    Kirkegaard Nielsen, Søren; Munkholm, Lars Juhl; Lamandé, Mathieu

    2017-01-01

    coulter depth varied up to ±5 mm between the blocks. In addition, significant depth variations between the individual coulters were found. The mean depths varied between −14.2 and −25.9 mm for the eleven coulters. The mean shallowest coulter depth (−14.2 mm) was measured for the coulter running...... in the wheel track of the tractor. The power spectral densities (distribution) of the coulter depth oscillation frequencies showed that the majority of oscillations occurred below 0.5 Hz without any natural vibration frequency. The study concluded that the instrumentation concept was functional for on...

  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

    Science.gov (United States)

    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.; hide

    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.

  7. The Norwegian hydrogen guide 2010

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-01

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

  8. Hydrogen, energy vector of the future?

    International Nuclear Information System (INIS)

    Perrin, J.; Deschamps, J.F.

    2004-01-01

    In the framework of a sustainable development with a reduction of the greenhouse gases emissions, the hydrogen seems a good solution because its combustion produces only water. From the today hydrogen industrial market, the authors examine the technological challenges and stakes of the hydrogen-energy. They detail the hydrogen production, distribution and storage and compare with the petrol and the natural gas. Then they explain the fuel cells specificity and realize a classification of the energy efficiency of many associations production-storage-distribution-use. a scenario of transition is proposed. (A.L.B.)

  9. Industrial implications of hydrogen

    International Nuclear Information System (INIS)

    Pressouyre, G.M.

    1982-01-01

    Two major industrial implications of hydrogen are examined: problems related to the effect of hydrogen on materials properties (hydrogen embrittlement), and problems related to the use and production of hydrogen as a future energy vector [fr

  10. Layered compression for high-precision depth data.

    Science.gov (United States)

    Miao, Dan; Fu, Jingjing; Lu, Yan; Li, Shipeng; Chen, Chang Wen

    2015-12-01

    With the development of depth data acquisition technologies, access to high-precision depth with more than 8-b depths has become much easier and determining how to efficiently represent and compress high-precision depth is essential for practical depth storage and transmission systems. In this paper, we propose a layered high-precision depth compression framework based on an 8-b image/video encoder to achieve efficient compression with low complexity. Within this framework, considering the characteristics of the high-precision depth, a depth map is partitioned into two layers: 1) the most significant bits (MSBs) layer and 2) the least significant bits (LSBs) layer. The MSBs layer provides rough depth value distribution, while the LSBs layer records the details of the depth value variation. For the MSBs layer, an error-controllable pixel domain encoding scheme is proposed to exploit the data correlation of the general depth information with sharp edges and to guarantee the data format of LSBs layer is 8 b after taking the quantization error from MSBs layer. For the LSBs layer, standard 8-b image/video codec is leveraged to perform the compression. The experimental results demonstrate that the proposed coding scheme can achieve real-time depth compression with satisfactory reconstruction quality. Moreover, the compressed depth data generated from this scheme can achieve better performance in view synthesis and gesture recognition applications compared with the conventional coding schemes because of the error control algorithm.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  12. Hydrogen production in a PWR during LOCA

    International Nuclear Information System (INIS)

    Cassette, P.

    1984-01-01

    Hydrogen generation during a PWR LOCA has been estimated for design basis accident and for two more severe hypothetical accidents. Hydrogen production during design basis accident is a rather slow mechanism, allowing in the worst case, 15 days to connect a hydrogen recombining unit to the containment atmosphere monitoring system. Hydrogen generated by steam oxidation during more severe hypothetical accidents was found limited by steam availability and fuel melting phenomena. Uncertainty is, however, still remaining on corium-zirconium-steam interaction. In the worst case, calculations lead to the production of 500 kg of hydrogen, thus leading to a volume concentration of 15% in containment atmosphere, assuming homogeneous hydrogen distribution within the reactor building. This concentration is within flammability limits but not within detonation limits. However, hydrogen detonation due to local hydrogen accumulation cannot be discarded. A major uncertainty subsisting on hydrogen hazard is hydrogen distribution during the first hours of the accident. This point determines the effects and consequences of local detonation or deflagration which could possibly be harmful to safeguard systems, or induce missile generation in the reactor building. As electrical supply failures are identified as an important contributor to severe accident risk, corrective actions have been taken in France to improve their reliability, including the installation of a gas turbine on each site to supplement the existing sources. These actions are thus contributing to hydrogen hazard reduction

  13. Corrosion pit depth extreme value prediction from limited inspection data

    International Nuclear Information System (INIS)

    Najjar, D.; Bigerelle, M.; Iost, A.; Bourdeau, L.; Guillou, D.

    2004-01-01

    Passive alloys like stainless steels are prone to localized corrosion in chlorides containing environments. The greater the depth of the localized corrosion phenomenon, the more dramatic the related damage that can lead to a structure weakening by fast perforation. In practical situations, because measurements are time consuming and expensive, the challenge is usually to predict the maximum pit depth that could be found in a large scale installation from the processing of a limited inspection data. As far as the parent distribution of pit depths is assumed to be of exponential type, the most successful method was found in the application of the statistical extreme-value analysis developed by Gumbel. This study aims to present a new and alternative methodology to the Gumbel approach with a view towards accurately estimating the maximum pit depth observed on a ferritic stainless steel AISI 409 subjected to an accelerated corrosion test (ECC1) used in automotive industry. This methodology consists in characterising and modelling both the morphology of pits and the statistical distribution of their depths from a limited inspection dataset. The heart of the data processing is based on the combination of two recent statistical methods that avoid making any choice about the type of the theoretical underlying parent distribution of pit depths: the Generalized Lambda Distribution (GLD) is used to model the distribution of pit depths and the Bootstrap technique to determine a confidence interval on the maximum pit depth. (authors)

  14. Hydrogen infrastructure development in The Netherlands

    International Nuclear Information System (INIS)

    Smit, R.; Weeda, M.; De Groot, A.

    2007-08-01

    Increasingly people think of how a hydrogen energy supply system would look like, and how to build and end up at such a system. This paper presents the work on modelling and simulation of current ideas among Dutch hydrogen stakeholders for a transition towards the widespread use of a hydrogen energy. Based mainly on economic considerations, the ideas about a transition seem viable. It appears that following the introduction of hydrogen in niche applications, the use of locally produced hydrogen from natural gas in stationary and mobile applications can yield an economic advantage when compared to the conventional system, and can thus generate a demand for hydrogen. The demand for hydrogen can develop to such an extent that the construction of a large-scale hydrogen pipeline infrastructure for the transport and distribution of hydrogen produced in large-scale production facilities becomes economically viable. In 2050, the economic viability of a large-scale hydrogen pipeline infrastructure spreads over 20-25 of the 40 regions in which The Netherlands is divided for modelling purposes. Investments in hydrogen pipelines for a fully developed hydrogen infrastructure are estimated to be in the range of 12,000-20,000 million euros

  15. Fluence dependence of disorder depth profiles in Pb implanted Si

    International Nuclear Information System (INIS)

    Christodoulides, C.E.; Kadhim, N.J.; Carter, G.

    1980-01-01

    The total, depth integrated disorder, induced by Pb implantation into Si at room temperature, initially increases rapidly with implantation fluence and then reaches a quasi saturation level where the increase with fluence is slow. Measurements of the depth distributions of the disorder, using high resolution low angle exit Rutherford Backscattering/Channelling analysis, suggest that the quasi saturation results from overlapping of disordered zones generated deep in the tail of the disorder-depth profiles. The depth of the disordered solid-crystal boundary, xsub(D), increases with ion fluence PHI, according to the relation xsub(D) = x bar + f(PHI).σ, where x bar is the most probable projected depth and σ the projected standard deviation of disorder generation. It is shown that this relationship is consistent with an approximately Gaussian depth distribution of disorder production. (author)

  16. Hydrogen-Induced Plastic Deformation in ZnO

    Science.gov (United States)

    Lukáč, F.; Čížek, J.; Vlček, M.; Procházka, I.; Anwand, W.; Brauer, G.; Traeger, F.; Rogalla, D.; Becker, H.-W.

    In the present work hydrothermally grown ZnO single crystals covered with Pd over-layer were electrochemically loaded with hydrogen and the influence of hydrogen on ZnO micro structure was investigated by positron annihilation spectroscopy (PAS). Nuclear reaction analysis (NRA) was employed for determination of depth profile of hydrogen concentration in the sample. NRA measurements confirmed that a substantial amount of hydrogen was introduced into ZnO by electrochemical charging. The bulk hydrogen concentration in ZnO determined by NRA agrees well with the concentration estimated from the transported charge using the Faraday's law. Moreover, a subsurface region with enhanced hydrogen concentration was found in the loaded crystals. Slow positron implantation spectroscopy (SPIS) investigations of hydrogen-loaded crystal revealed enhanced concentration of defects in the subsurface region. This testifies hydrogen-induced plastic deformation of the loaded crystal. Absorbed hydrogen causes a significant lattice expansion. At low hydrogen concentrations this expansion is accommodated by elastic straining, but at higher concentrations hydrogen-induced stress exceeds the yield stress in ZnO and plastic deformation of the loaded crystal takes place. Enhanced hydrogen concentration detected in the subsurface region by NRA is, therefore, due to excess hydrogen trapped at open volume defects introduced by plastic deformation. Moreover, it was found that hydrogen-induced plastic deformation in the subsurface layer leads to typical surface modification: formation of hexagonal shape pyramids on the surface due to hydrogen-induced slip in the [0001] direction.

  17. The fusion-hydrogen energy system

    International Nuclear Information System (INIS)

    Williams, L.O.

    1994-01-01

    This paper will describe the structure of the system, from energy generation and hydrogen production through distribution to the end users. It will show how stationary energy users will convert to hydrogen and will outline ancillary uses of hydrogen to aid in reducing other forms of pollution. It will show that the adoption of the fusion hydrogen energy system will facilitate the use of renewable energy such as wind and solar. The development of highly efficient fuel cells for production of electricity near the user and for transportation will be outlined. The safety of the hydrogen fusion energy system is addressed. This paper will show that the combination of fusion generation combined with hydrogen distribution will provide a system capable of virtually eliminating the negative impact on the environment from the use of energy by humanity. In addition, implementation of the energy system will provide techniques and tools that can ameliorate environmental problems unrelated to energy use. (Author)

  18. Hydrogen storage and integrated fuel cell assembly

    Science.gov (United States)

    Gross, Karl J.

    2010-08-24

    Hydrogen is stored in materials that absorb and desorb hydrogen with temperature dependent rates. A housing is provided that allows for the storage of one or more types of hydrogen-storage materials in close thermal proximity to a fuel cell stack. This arrangement, which includes alternating fuel cell stack and hydrogen-storage units, allows for close thermal matching of the hydrogen storage material and the fuel cell stack. Also, the present invention allows for tailoring of the hydrogen delivery by mixing different materials in one unit. Thermal insulation alternatively allows for a highly efficient unit. Individual power modules including one fuel cell stack surrounded by a pair of hydrogen-storage units allows for distribution of power throughout a vehicle or other electric power consuming devices.

  19. Defence in depth perspectives

    International Nuclear Information System (INIS)

    Veneau, Tania; Ferrier, Agnes; Barbaud, Jean

    2017-01-01

    The Defence in Depth (DiD) concept was introduced to the field of nuclear safety in the sixties and early seventies. Even though it was not well developed at the beginning, the principles rapidly became close to those currently used. The concept was then composed of 3 levels, and was already associated with operating conditions. These principles have progressed over time and now there are five levels, including progressively situations issued from design extension conditions, to cope with severe accidents and dealing with accident management off-site. Indeed, human and organizational features are considered as a part of the safety provisions at all levels in an integrated approach that is not just related to reactor design. That's the current vision from IAEA, addressed first in INSAG 3 then in INSAG 10, and in the IAEA standards requirements currently addressed by SSR-2/1 superseding NS-R-1). These five levels of DiD are also referred to in other texts including WENRA documents in Europe, but also in the national requirements from different countries. Thus, the application of DiD principle has become a recognized international practice. The 2011 Fukushima Daiichi accidents, even if they raised many questions on nuclear safety issues, confirmed the merits of the DiD concept. Indeed, lessons learned from the accidents have reinforced the use of the DiD concept to ensure adequate safety. The discussions focused more on the implementation of the concept (how it has been or can be used in practice) than the concept itself, and in particular on the following subjects: the notion of level robustness, generally addressed separately from the levels definition, but playing an important role for the efficiency of the concept; the notion of levels independence and the need for strengthening them; the role of diversity to achieve levels independence. However, a prescription of additional diversity and independence across all safety levels could result in inappropriately

  20. Hydrogen and nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, N J.D.

    1976-03-01

    There is much debate about the form and availability of energy supplies in the future. It is assumed that nuclear fuel is the only source of controlled energy. Energy inputs from the sun, the wind, the waves, the tides, and other sources not available in the form of fuels are not excluded. In this situation it has been argued that because the cost of transporting energy as a liquid or gaseous fuel is lower than the cost of transmitting energy as electricity it would be more effective to transmit and distribute energy from nuclear fuel in the form of a chemical fuel such as hydrogen. This argument has been critized by Hampson et al., (EAPA 1: 2200) who calculate that the reduced costs of transmission only outweigh the costs of production over distances so large that there appears no realistic application. These calculations neglect the time variation of electricity supply which is fundamental to the planning of an electricity supply system; they also do not appear to do justice to the relationship between the costs of hydrogen and electricity production in an integrated system. These points are included in the analysis presented here by means of the observation that hydrogen generated by nuclear plants with high capital cost and low running cost will be burned by the supply system itself in low-capital-cost plants, suitable for chemical fuels, in order to meet peak demands on the system. This establishes a relationship between the long-run marginal costs of electricity at various times of the day and the long-run marginal cost of hydrogen. These costs are then used to show that, in certain favorable, but common, circumstances, electrolytic hydrogen is the lower-cost source of energy. (from Introduction)

  1. Anomalously deep penetration of hydrogen into niobium under action of pulse high temperature hydrogen plasma

    International Nuclear Information System (INIS)

    Didyk, A.Yu.

    2011-01-01

    The method of elastic recoil detection (ERD) has been used for the study of storage and redistribution processes of hydrogen atoms under the influence of pulse high temperature hydrogen plasma obtained using the 'Plasma Focus' PF-4 set-up in three high purity niobium foils. It was established that with an increase of number of PF-4 set-up pulses there occur spreading and transfer of implanted hydrogen atoms to large depths in three Nb-foils which are significantly larger than the projected range of hydrogen ions (with the velocity ∼ 10 8 cm/s). The maximum hydrogen concentration up to 60 at. % is reached in the nearest to Ph-4 surface of the third Nb-foil at 20 impulses of the Ph-4 set-up. The observed phenomenon can be described by transfer of implanted hydrogen atoms under the action of powerful shock waves, created by pulse hydrogen plasma and (or) by accelerating hydrogen atom diffusion under the influence of compression straining wave at the front of the shock wave at redistribution of hydrogen atoms at large depths. Similar behavior was discovered and described also in series of nickel, vanadium, niobium and tantalum foils (two or three foils and more in a series) including series of foils from heterogeneous (different) materials, which were studied, too

  2. Hydrogen production by nuclear heat

    International Nuclear Information System (INIS)

    Crosbie, Leanne M.; Chapin, Douglas

    2003-01-01

    A major shift in the way the world obtains energy is on the horizon. For a new energy carrier to enter the market, several objectives must be met. New energy carriers must meet increasing production needs, reduce global pollution emissions, be distributed for availability worldwide, be produced and used safely, and be economically sustainable during all phases of the carrier lifecycle. Many believe that hydrogen will overtake electricity as the preferred energy carrier. Hydrogen can be burned cleanly and may be used to produce electricity via fuel cells. Its use could drastically reduce global CO 2 emissions. However, as an energy carrier, hydrogen is produced with input energy from other sources. Conventional hydrogen production methods are costly and most produce carbon dioxide, therefore, negating many of the benefits of using hydrogen. With growing concerns about global pollution, alternatives to fossil-based hydrogen production are being developed around the world. Nuclear energy offers unique benefits for near-term and economically viable production of hydrogen. Three candidate technologies, all nuclear-based, are examined. These include: advanced electrolysis of water, steam reforming of methane, and the sulfur-iodine thermochemical water-splitting cycle. The underlying technology of each process, advantages and disadvantages, current status, and production cost estimates are given. (author)

  3. Hydrogen, fuel of the future?

    International Nuclear Information System (INIS)

    Bello, B.

    2008-01-01

    The European project HyWays has drawn out the road map of hydrogen energy development in Europe. The impact of this new energy vector on the security of energy supplies, on the abatement of greenhouse gases and on the economy should be important in the future. This article summarizes the main conclusions of the HyWays study: CO 2 emissions, hydrogen production mix, oil saving abatement, economic analysis, contribution of hydrogen to the development of renewable energies, hydrogen uses, development of regional demand and of users' centers, transport and distribution. The proposals of the HyWays consortium are as follows: implementing a strong public/private European partnership to reach the goals, favoring market penetration, developing training, tax exemption on hydrogen in the initial phase for a partial compensation of the cost difference, inciting public fleets to purchase hydrogen-fueled vehicles, using synergies with other technologies (vehicles with internal combustion engines, hybrid vehicles, biofuels of second generation..), harmonizing hydrogen national regulations at the European scale. (J.S.)

  4. Evaluation of Depth of Field for depth perception in DVR

    KAUST Repository

    Grosset, A.V.Pascal; Schott, Mathias; Bonneau, Georges-Pierre; Hansen, Charles D.

    2013-01-01

    In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

  5. Evaluation of Depth of Field for depth perception in DVR

    KAUST Repository

    Grosset, A.V.Pascal

    2013-02-01

    In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

  6. Depth concentrations of deuterium ions implanted into some pure metals and alloys

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Wisniewski, R.; Kitowski, K.; Wilczynska, T.; Hofman, A.; Kulikauskas, V.; Shiryaev, A.A.; Zubavichyus, Ya.V.

    2011-01-01

    Pure metals (Cu, Ti, Zr, V, Pd) and diluted Pd alloys (Pd-Ag, Pd-Pt, Pd-Ru, Pd-Rh) were implanted by 25-keV deuterium ions at fluences in the range (1.2-2.3) x 10 22 D + /m 2 . The post-treatment depth distributions of deuterium ions were measured 10 days and three months after the implantation by using Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS). Comparison of the obtained results allowed us to make conclusions about relative stability of deuterium and hydrogen gases in pure metals and diluted Pd alloys. Very high diffusion rates of implanted deuterium ions from V and Pd pure metals and Pd alloys were observed. Small-angle X-ray scattering revealed formation of nanosized defects in implanted corundum and titanium

  7. Quantitative analysis of hydrogen and of its isotopes at the surface of the solids

    International Nuclear Information System (INIS)

    Trocellier, P.

    2007-01-01

    For analyzing the hydrogen isotopes, the nature of the probe which allows to excite the considered material and to give the hydrogen answer is multiple and is supported by various physical principles. The different available techniques are presented and several examples are given. To conclude, it is possible to determine the superficial or volume distribution of hydrogen or of one of its two heavy isotopes in choosing the most physico-chemical method. The choice of the technique to use depends of the wanted performance. In order to simplify, we can associate: 1)the sensitivity with mass spectrometry; 2)the depth resolution with the glow discharge, the SIMS and the resonant nuclear reaction; 3)the studied depth with the accelerated ions beams and the AMS; 4)the distribution image with the electrons stimulated desorption, the beta autoradiography and the ERDA; 5)the quantitative profile with the accelerated ions beams techniques; 6)the isotopic analysis with mass spectrometry and the accelerated ions beams. In order to be sure of the relevance of the measurements result, it is indicated to combine the advantages and the performances of several techniques as SIMS and NRA or FTIR and ERDA for instance. (O.M.)

  8. Coupled hydrogen moderator optimization with ortho/para hydrogen ratio

    International Nuclear Information System (INIS)

    Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Ikeda, Yujiro

    2004-01-01

    Neutronic performance of a coupled hydrogen moderator was studied as a function of para hydrogen concentration, moderator thickness and height, premoderator thickness, etc. for the J-PARC spallation neutron source. It was found that a thick (140 mm) moderator with 100% para-hydrogen was optimal to provide a high time- and energy-integrated neutron intensity below 15 meV and high pulse-peak intensities at lower energies. Distribution of the cold neutrons on a moderator viewed surface was studied and found to exhibit an intensity-enhanced region at the fringe part near the premoderator. This rather peculiar distribution suggested that the moderator and the viewed surface must be designed so as to take the full advantage of the brighter region near the premoderator

  9. WATER DEPTH and Other Data (NODC Accession 9400096)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD); and bathythermograph (XBT) data were collected as part of Distribution/Abundance of Marine Mammals in Gulf of Mexico...

  10. Circumnebular neutral hydrogen in planetary nebulae

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  11. Profiling hydrogen in materials using ion beams

    International Nuclear Information System (INIS)

    Ziegler, J.F.; Wu, C.P.; Williams, P.

    1977-01-01

    Over the last few years many ion beam techniques have been reported for the profiling of hydrogen in materials. Nine of these were evaluated using similar samples of hydrogen ion-implanted into silicon. When possible the samples were analyzed using two or more techniques to confirm the ion-implanted accuracy. The results of this analysis which has produced a consensus profile of H in silicon which is useful as a calibration standard are reported. The analytical techniques used have capabilities ranging from very high depth resolution (approximately 50 A) and high sensitivity (less than 1 ppM) to deep probes for hydrogen which can sample throughout thin sheets

  12. Galactic neutral hydrogen emission-absorption observations from Arecibo

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  13. Clean energy and the hydrogen economy.

    Science.gov (United States)

    Brandon, N P; Kurban, Z

    2017-07-28

    In recent years, new-found interest in the hydrogen economy from both industry and academia has helped to shed light on its potential. Hydrogen can enable an energy revolution by providing much needed flexibility in renewable energy systems. As a clean energy carrier, hydrogen offers a range of benefits for simultaneously decarbonizing the transport, residential, commercial and industrial sectors. Hydrogen is shown here to have synergies with other low-carbon alternatives, and can enable a more cost-effective transition to de-carbonized and cleaner energy systems. This paper presents the opportunities for the use of hydrogen in key sectors of the economy and identifies the benefits and challenges within the hydrogen supply chain for power-to-gas, power-to-power and gas-to-gas supply pathways. While industry players have already started the market introduction of hydrogen fuel cell systems, including fuel cell electric vehicles and micro-combined heat and power devices, the use of hydrogen at grid scale requires the challenges of clean hydrogen production, bulk storage and distribution to be resolved. Ultimately, greater government support, in partnership with industry and academia, is still needed to realize hydrogen's potential across all economic sectors.This article is part of the themed issue 'The challenges of hydrogen and metals'. © 2017 The Author(s).

  14. Theoretical examination of the trapping of ion-implanted hydrogen in metals

    International Nuclear Information System (INIS)

    Myers, S.M.; Nordlander, P.; Besenbacher, F.; Norskov, J.K.

    1986-01-01

    Theoretical analysis of the defect trapping of ion-implanted hydrogen in metals has been extended in two respects. A new transport formalism has been developed which takes account not only of the diffusion, trapping, and surface release of the hydrogen, which were included in earlier treatments, but also the diffusion, recombination, agglomeration, and surface annihilation of the vacancy and interstitial traps. In addition, effective-medium theory has been used to examine multiple hydrogen occupancy of the vacancy, and, for the fcc structure, appreciable binding enthalpies relative to the solution site have been found for occupancies of up to six. These extensions have been employed to model the depth distribution of ion-implanted hydrogen in Ni and Al during linear ramping of temperature, and the results have been used to interpret previously published data from these metals. The agreement between theory and experiment is good for both systems. In the case of Ni, the two experimentally observed hydrogen-release stages are both accounted for in terms of trapping at vacancies with a binding enthalpy that depends upon occupancy in accord with effective-medium theory

  15. Factors controlling contrail cirrus optical depth

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2009-08-01

    Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

    A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

  16. Hydrogen evolution from aqueous-phase photocatalytic reforming of ethylene glycol over Pt/TiO{sub 2} catalysts: Role of Pt and product distribution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fuying [State Key Laboratory of Photocatalysis on Energy and Environment, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002 (China); College of Resources and Chemical Engineering, Sanming University, Sanming 365004 (China); Gu, Quan [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shanxi Normal University, Xi’an 710062 (China); Niu, Yu [College of Resources and Chemical Engineering, Sanming University, Sanming 365004 (China); School of Chemical Engineering, Fuzhou University, Fuzhou 350116 (China); Wang, Renzhang [College of Resources and Chemical Engineering, Sanming University, Sanming 365004 (China); Tong, Yuecong; Zhu, Shuying; Zhang, Hualei [State Key Laboratory of Photocatalysis on Energy and Environment, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002 (China); Zhang, Zizhong, E-mail: z.zhang@fzu.edu.cn [State Key Laboratory of Photocatalysis on Energy and Environment, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002 (China); Wang, Xuxu [State Key Laboratory of Photocatalysis on Energy and Environment, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002 (China)

    2017-01-01

    Highlights: • Photocatalytic EG reforming generates many hydrocarbons besides H{sub 2}, CO{sub 2} and CO. • Pt loading greatly improves the photocatalytic activity of TiO{sub 2} for EG reforming. • Half amount of the produced H{sub 2} over Pt/TiO{sub 2} originates from EG reforming. - Abstract: Pt nanoparticles were loaded on anatase TiO{sub 2} by the photodeposition method to investigate their photocatalytic activity for H{sub 2} evolution in an aqueous solution containing a certain amount of ethylene glycol (EG) as the sacrificial agent. The surface properties and chemical states of the Pt/TiO{sub 2} sample were characterized by X-ray powder diffraction analysis, Brunauer–Emmett–Teller surface area analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, and electrochemical resistance. The aqueous-phase photocatalytic EG reforming using Pt/TiO{sub 2} and anatase TiO{sub 2} generated not only H{sub 2} and CO{sub 2}, but also CO, CH{sub 4}, C{sub 2}H{sub 6}, and C{sub 2}H{sub 4}. Moreover, the amount of formate and acetate complexes in the solution increased gradually. The EG adsorption and gas-phase intermediates during photocatalytic reaction processes were investigated by the in situ FTIR spectrum. Finally, the photocatalytic EG reforming reaction mechanism was elucidated. This helped to better understand the role of a sacrificial agent in a photocatalytic hydrogen production.

  17. GNF Defense in Depth Update

    Energy Technology Data Exchange (ETDEWEB)

    Lingenfelter, Andrew A.; Schneider, Robert J.; Cantonwine, Paul E.; Moore, Brian; Rea, John; Crawford, Douglas C. [Global Nuclear Fuel, P.O. Box 780 M/C H25, Wilmington, NC 28402 (United States)

    2009-06-15

    Global Nuclear Fuel (GNF) has designed, fabricated, and placed into operation more than 9 million fuel rods in approximately 135 thousand assemblies. Customer satisfaction has always compelled GNF to reduce fuel rod failures (defined here as fuel rods that breach or leak in service), However, increasing success with and subsequent expectations for economic performance of nuclear reactor plants have raised broader Industry emphasis on fuel reliability. In 2005, GNF established its Defense-in-Depth (DID) Program for the purpose of focusing attention on the many aspects of fuel design, fabrication, performance, and utilization that affect fuel reliability as well as on the key methods that govern the utilization of GNF fuel. The Program is structured to address each of the identified in-service, fuel failure mechanisms. This paper provides a summary of GNF fuel performance, following previous updates. This paper will discuss recent GNF fuel reliability and channel performance, GNF2 introduction status, and methods. GNF's more recent fuel experience includes approximately 3.8 million GE11/13 (9x9) and GE12/14 (10x10) fuel rods, well over half of which are the GE12/14 design. (Those figures also include roughly 25,000 recently-introduced GNF2 fuel rods.) Reliability, expressed as annual, observed fuel failure rates (i.e., number of rods failed each year divided by the number of opportunities, or fuel rods in service), has improved for each year since 2005. The GNF fuel failure rate for years leading up to 2007 and 2008 has been on the order of 5 to 7 ppm (excluding the corrosion events of 2001-2003), and as of this writing (January 2009) the current in-service failure has decreased to around 1.5 ppm. Failures in GE14 fuel rod failures have been primarily due to debris-fretting (> 60%), with other failures being duty-related or yet undetermined. The only failure observed in GNF2 to date was a single, early-life debris failure in a bundle not equipped with GNF

  18. Significant change of local atomic configurations at surface of reduced activation Eurofer steels induced by hydrogenation treatments

    Energy Technology Data Exchange (ETDEWEB)

    Greculeasa, S.G.; Palade, P.; Schinteie, G. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Kuncser, A.; Stanciu, A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, 77125, Bucharest-Magurele (Romania); Lungu, G.A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Porosnicu, C.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, 77125, Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania)

    2017-04-30

    Highlights: • Engineering of Eurofer slab properties by hydrogenation treatments. • Hydrogenation modifies significantly the local atomic configurations at the surface. • Hydrogenation increases the expulsion of the Cr atoms toward the very surface. • Approaching binomial atomic distribution by hydrogenation in the next surface 100 nm. - Abstract: Reduced-activation steels such as Eurofer alloys are candidates for supporting plasma facing components in tokamak-like nuclear fusion reactors. In order to investigate the impact of hydrogen/deuterium insertion in their crystalline lattice, annealing treatments in hydrogen atmosphere have been applied on Eurofer slabs. The resulting samples have been analyzed with respect to local structure and atomic configuration both before and after successive annealing treatments, by X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and conversion electron Mössbauer spectroscopy (CEMS). The corroborated data point out for a bcc type structure of the non-hydrogenated alloy, with an average alloy composition approaching Fe{sub 0.9}Cr{sub 0.1} along a depth of about 100 nm. EDS elemental maps do not indicate surface inhomogeneities in concentration whereas the Mössbauer spectra prove significant deviations from a homogeneous alloying. The hydrogenation increases the expulsion of the Cr atoms toward the surface layer and decreases their oxidation, with considerable influence on the surface properties of the steel. The hydrogenation treatment is therefore proposed as a potential alternative for a convenient engineering of the surface of different Fe-Cr based alloys.

  19. Estimating the Rut Depth by UAV Photogrammetry

    Directory of Open Access Journals (Sweden)

    Paavo Nevalainen

    2017-12-01

    Full Text Available The rut formation during forest operations is an undesirable phenomenon. A methodology is being proposed to measure the rut depth distribution of a logging site by photogrammetric point clouds produced by unmanned aerial vehicles (UAV. The methodology includes five processing steps that aim at reducing the noise from the surrounding trees and undergrowth for identifying the trails. A canopy height model is produced to focus the point cloud on the open pathway around the forest machine trail. A triangularized ground model is formed by a point cloud filtering method. The ground model is vectorized using the histogram of directed curvatures (HOC method to produce an overall ground visualization. Finally, a manual selection of the trails leads to an automated rut depth profile analysis. The bivariate correlation (Pearson’s r between rut depths measured manually and by UAV photogrammetry is r = 0.67 . The two-class accuracy a of detecting the rut depth exceeding 20 cm is a = 0.65 . There is potential for enabling automated large-scale evaluation of the forestry areas by using autonomous drones and the process described.

  20. Asymptotic analysis of methane-hydrogen-air mixtures

    NARCIS (Netherlands)

    Hermanns, R.T.E.; Bastiaans, R.J.M.; Goey, de L.P.H.

    2005-01-01

    In this paper an asymptotic analysis of de Goey et al.concerning premixed stoichiometric methane-hydrogen-air flames is analyzed in depth. The analysis is performed with up to 50 mole percent of hydrogen in the fuel, at gas inlet temperatures ranging from 300 K to 650 K and pressures from 1 to 15

  1. Industrial view of Hydrogen Energy

    International Nuclear Information System (INIS)

    Francois Jackow

    2006-01-01

    Industrial Gases Companies have been mastering Hydrogen production, distribution, safe handling and applications for several decades for a wide range of gas applications. This unique industrial background positioned these companies to play a key role in the emerging Hydrogen Energy market, which can rely, at early stage of development, on already existing infrastructure, logistics and technical know-how. Nevertheless, it is important to acknowledge that Hydrogen Energy raised specific challenges which are not totally addressed by industrial gas activities. The main difference is obviously in the final customer profile, which differs significantly from the qualified professional our industry is used to serve. A non professional end-user, operating with Hydrogen at home or on board of his family car, has to be served with intrinsically safe and user-friendly solutions that exceed by far the industrial specifications already in place. Another significant challenge is that we will need breakthroughs both in terms of products and infrastructure, with development time frame that may require several decades. The aim of this presentation is to review how a company like Air Liquide, worldwide leader already operating more than 200 large hydrogen production sites, is approaching this new Hydrogen Energy market, all along the complete supply chain from production to end-users. Our contributions to the analysis, understanding and deployment of this new Energy market, will be illustrated by the presentation of Air Liquide internal development's as well as our participation in several national and European projects. (author)

  2. [Potential Carbon Fixation Capability of Non-photosynthetic Microbial Community at Different Depth of the South China Sea and Its Response to Different Electron Donors].

    Science.gov (United States)

    Fang, Feng; Wang, Lei; Xi, Xue-fei; Hu, Jia-jun; Fu, Xiao-hua; Lu, Bing; Xu, Dian-sheng

    2015-05-01

    The seawater samples collected from many different areas with different depth in the South China Sea were cultivated using different electron donors respectively. And the variation in the potential carbon fixation capability ( PCFC ) of non-photosynthetic microbial community (NPMC) in seawater with different depth was determined after a cycle of cultivation through the statistic analysis. In addition, the cause for the variation was clarified through analyzing key gene abundance regarding CO2 fixation and characteristics of seawater with different depth. The result showed that the PCFCs of NPMC in seawater with different depth were generally low and had no significant difference when using NaNO2 as the electron donor. The PCFC of NPMC in surface seawater was higher than that in deep seawater when using H2 as the electron donor, on the contrary, the PCFC of NPMC in deep seawater was higher than that in surface seawater when using Na2S2O3 as the electron donor. The abundance of the main CO2 fixation gene cbbL in surface seawater was higher than that in deep seawater while the cbbM gene abundance in deep seawater was higher than that in surface seawater. Most hydrogen-oxidizing bacteria had the cbbL gene, and most sulfur bacteria had the cbbM gene. The tendency of seawater cbbL/cbbM gene abundance with the change of depth revealed that there were different kinds of bacteria accounting for the majority in NPMC fixing CO2 at different depth of ocean, which led to different response of PCFC of NPMC at different depth of the sea to different electron donors. The distributions of dissolved oxygen and inorganic carbon concentration with the change of the depth of the sea might be an important reason leading to the difference of NPMC structure and even the difference of PCFC at different depth of the sea.

  3. Destructive hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Terrisse, H; Dufour, L

    1929-01-21

    Oils of high boiling point, e.g. gas oil, lamp oil, schist oil, brown coal tar etc., are converted into motor benzine by heating them at 200 to 500/sup 0/C under pressure of 5 to 40 kilograms/cm/sup 2/ in the presence of ferrous chloride and gases such as hydrogen, or water gas, the desulfurization of the oils proceeding simultaneously. One kilogram of lamp oil and 100 g. ferrous chloride are heated in an autoclave in the presence of water gas under a pressure of 18 kg/cm/sup 2/ to 380 to 400/sup 0/C. The gaseous products are allowed to escape intermittently and are replaced by fresh water gas. A product distilling between 35 and 270/sup 0/C is obtained.

  4. A hydrogen economy: opportunities and challenges

    International Nuclear Information System (INIS)

    Tseng, P.; Lee, J.; Friley, P.

    2005-01-01

    A hydrogen economy, the long-term goal of many nations, can potentially confer energy security, along with environmental and economic benefits. However, the transition from a conventional petroleum-based energy system to a hydrogen economy involves many uncertainties, such as the development of efficient fuel-cell technologies, problems in hydrogen production and its distribution infrastructure, and the response of petroleum markets. This study uses the US MARKAL model to simulate the impacts of hydrogen technologies on the US energy system and to identify potential impediments to a successful transition. Preliminary findings highlight possible market barriers facing the hydrogen economy, as well as opportunities in new R and D and product markets for bioproducts. Quantitative analysis also offers insights on policy options for promoting hydrogen technologies. (author)

  5. Ammonia for hydrogen storage: challenges and opportunities

    DEFF Research Database (Denmark)

    Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

    2008-01-01

    The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

  6. Hydrogen and chlorine detection at the SiO2/Si interface

    International Nuclear Information System (INIS)

    Tsong, I.S.T.; Monkowski, M.D.; Monkowski, J.R.; Wintenberg, A.L.; Miller, P.D.; Moak, C.D.

    1981-01-01

    Hydrogen and chlorine depth profiles were obtained on a series of silicon oxides thermally grown in HCl/O 2 and Cl 2 /O 2 ambients at 1100 0 C for 15 minutes using the 19 F nuclear reaction and SIMS techniques. The data show close correlation between the H and Cl profiles in both the HCl/O 2 and Cl 2 /O 2 oxides. While the H and Cl appear to be enriched at the SiO 2 /Si interface of the HCl/O 2 oxides, they are higher in concentration and more evenly distributed in the oxide bulk of the Cl 2 /O 2 oxides

  7. Particle size distribution in soils and marine sediments by laser diffraction using Malvern Mastersizer 2000—method uncertainty including the effect of hydrogen peroxide pretreatment

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Keck, Hannes; Andersen, Thorbjørn Joest

    2018-01-01

    with less than 1% C and some marine sediments. Materials and methods: The method uncertainty for particle size analysis by the laser diffraction method using or not using H2O2 pretreatment followed by 2 min ultrasound and 1-mm sieving was determined for two soil samples and two aquatic sediments......Purpose: Methods for particle size distribution (PSD) determination by laser diffraction are not standardized and differ between disciplines and sectors. The effect of H2O2 pretreatment before a sonication treatment in laser diffraction analysis of soils and marine sediments was examined on soils...... pretreatment on the PSD was small and not significant. The standard deviation (std) in particle size fractions increased with par