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Sample records for buffer gas induced

  1. Buffer-gas-induced absorption resonances in Rb vapor

    International Nuclear Information System (INIS)

    Mikhailov, Eugeniy E.; Novikova, Irina; Rostovtsev, Yuri V.; Welch, George R.

    2004-01-01

    We observe transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a Λ interaction configuration in a cell filled with 87 Rb and a buffer gas. This transformation occurs as one-photon detuning of the coupling fields is varied from the atomic transition. No such absorption resonance is found in the absence of a buffer gas. The width of the absorption resonance is several times smaller than the width of the EIT resonance, and the changes of absorption near these resonances are about the same. Similar absorption resonances are detected in the Hanle configuration in a buffered cell

  2. High-quality electromagnetically-induced absorption resonances in a buffer-gas-filled vapour cell

    Science.gov (United States)

    Brazhnikov, D. V.; Ignatovich, S. M.; Vishnyakov, V. I.; Skvortsov, M. N.; Andreeva, Ch; Entin, V. M.; Ryabtsev, I. I.

    2018-02-01

    Magneto-optical subnatural-linewidth resonances of electromagnetically-induced absorption (EIA) in an alkali vapour cell have been experimentally studied. The observation configuration includes using two counter-propagating pumps and probe light waves with mutually orthogonal linear polarizations, exciting an open optical transition in the 87Rb D 1 line in the presence of argon buffer gas. The EIA signals registered in a probe-wave transmission reach an unprecedented contrast of about 135% with respect to the wide ‘Doppler’ absorption pedestal and 29% with respect to the level of background transmission signal. These contrast values correspond to a relatively small resonance full width at half maximum of about 7.2 mG (5.2 kHz). The width of the narrowest EIA resonance observed is about 2.1 mG (1.5 kHz). To our knowledge, such a large relative contrast at the kHz-width is the record result for EIA resonances. In general, the work has experimentally proved that the magneto-optical scheme used has very good prospects for various quantum technologies (quantum sensors of weak magnetic fields, optical switches and other photonic elements).

  3. Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

    International Nuclear Information System (INIS)

    Nikolić, S N; Radonjić, M; Krmpot, A J; Lučić, N M; Zlatković, B V; Jelenković, B M

    2013-01-01

    Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a Π laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 . (paper)

  4. Buffer gas cooling and mixture analysis

    Science.gov (United States)

    Patterson, David S.; Doyle, John M.

    2018-03-06

    An apparatus for spectroscopy of a gas mixture is described. Such an apparatus includes a gas mixing system configured to mix a hot analyte gas that includes at least one analyte species in a gas phase into a cold buffer gas, thereby forming a supersaturated mixture to be provided for spectroscopic analysis.

  5. Optimal buffer gas pressure for laser-induced fluorescence detection of the iodine-129 isotope in the atmosphere

    International Nuclear Information System (INIS)

    Kireev, S.V.; Pit'ko, A.V.; Shnyrev, S.L.

    1995-01-01

    The effect of atmospheric air pressure on the intensity of iodine-129 vapor fluorescence excited by a He-Ne (633 nm) laser is studied. It is shown that to achieve the maximum intensity of fluorescence of molecular iodine-129, it is advantageous, first, to use a 3 He- 20 Ne laser for excitation, and second, to detect atmospheric iodine impurities in the gas mixture under analysis evacuated to 2 x 10 18 - 4 x 10 18 mol/cm 3 . In this case, the sensitivity increases about twofold. 7 refs., 4 figs

  6. Database on gas migration tests through bentonite buffer material

    International Nuclear Information System (INIS)

    Tanai, Kenji

    2009-02-01

    Carbon steel is a candidate material for an overpack for geological disposal of high-level radioactive waste in Japan. The corrosion of the carbon steel overpack in aqueous solution under anoxic conditions will cause the generation of hydrogen gas, which may affect hydrological and mechanical properties of the bentonite buffer. To evaluate such an effect of gas generation, it is necessary to develop a model of gas migration through bentonite buffer material taking account of data obtained from experiments. The gas migration experiments under both unsaturated and saturated conditions have been carried out to clarify the fundamental characteristics of bentonite for gas migration. This report compiles the experimental data obtained from gas migration tests for buffer material which has been conducted by JAEA until December, 2007. A CD-ROM is attached as an appendix. (author)

  7. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.

    2014-01-01

    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed

  8. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  9. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Science.gov (United States)

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  10. Neutron electric dipole moment measurement with a buffer gas comagnetometer

    International Nuclear Information System (INIS)

    Masuda, Yasuhiro; Asahi, Koichiro; Hatanaka, Kichiji; Jeong, Sun-Chan; Kawasaki, Shinsuke; Matsumiya, Ryohei; Matsuta, Kensaku; Mihara, Mototsugu; Watanabe, Yutaka

    2012-01-01

    A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth's rotation is removed. As a result, the GPE is reduced below 10 −28 e cm. -- Highlights: ► A method of high precision neutron EDM measurement is described. ► Geometric phase effects are discussed in terms of Dyson series. ► A magnetic field drift is compensated by means of a buffer gas magnetometer. ► Geometric phase effects are greatly suppressed. ► The systematic error is reduced by two orders of magnitude compared with before.

  11. Neutron electric dipole moment measurement with a buffer gas comagnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yasuhiro, E-mail: yasuhiro.masuda@kek.jp [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Asahi, Koichiro [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Hatanaka, Kichiji [RCNP, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Jeong, Sun-Chan; Kawasaki, Shinsuke [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Matsumiya, Ryohei [RCNP, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Matsuta, Kensaku; Mihara, Mototsugu [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Watanabe, Yutaka [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2012-03-19

    A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth's rotation is removed. As a result, the GPE is reduced below 10{sup −28}e cm. -- Highlights: ► A method of high precision neutron EDM measurement is described. ► Geometric phase effects are discussed in terms of Dyson series. ► A magnetic field drift is compensated by means of a buffer gas magnetometer. ► Geometric phase effects are greatly suppressed. ► The systematic error is reduced by two orders of magnitude compared with before.

  12. Optically pumped alkali laser and amplifier using helium-3 buffer gas

    Science.gov (United States)

    Beach, Raymond J.; Page, Ralph; Soules, Thomas; Stappaerts, Eddy; Wu, Sheldon Shao Quan

    2010-09-28

    In one embodiment, a laser oscillator is provided comprising an optical cavity, the optical cavity including a gain medium including an alkali vapor and a buffer gas, the buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Additionally, an optical excitation source is provided. Furthermore, the laser oscillator is capable of outputting radiation at a first frequency. In another embodiment, an apparatus is provided comprising a gain medium including an alkali vapor and a buffer gas including .sup.3He gas, wherein if .sup.4He gas is also present in the buffer gas, the ratio of the concentration of the .sup.3He gas to the .sup.4He gas is greater than 1.37.times.10.sup.-6. Other embodiments are also disclosed.

  13. Influence of electrode, buffer gas and control gear on metal halide lamp performance

    International Nuclear Information System (INIS)

    Lamouri, A; Naruka, A; Sulcs, J; Varanasi, C V; Brumleve, T R

    2005-01-01

    In this paper the influence of electrode composition, buffer gas fill pressure and control gear on the performance of metal halide lamps is investigated. It is shown that pure tungsten electrodes improve lumen maintenance and reduce voltage rise over lamp life. An optimum buffer gas fill pressure condition is discovered which allows for reduced electrode erosion during lamp starting as well as under normal operating conditions. Use of electronic control gear is shown to improve the performance of metal halide lamps

  14. Progress Toward Buffer Gas Cooling of a 1 μB Species

    Science.gov (United States)

    Johnson, Cort; Newman, Bonna; Brahms, Nathan; Decarvalho, Robert; Li, Chih-Hao; Greytak, Tom; Kleppner, Dan; Doyle, John

    2006-05-01

    Thermalization with a non-magnetic ^3He buffer gas has been demonstrated to be an effective means of removing heat from a sample of hot magnetic atoms held in a magnetic trap[1]. To thermally isolate the atoms, it is necessary to remove the buffer gas without sweeping away the magnetically trapped atoms. The magnetic trap strength is proportional to the magnitude of the atom's moment. This is the primary reason that trapping a 1 μB species has never been realized in a buffer gas cooling experiment. Eventually, we plan to use this technique to trap and cool atomic hydrogen and deuterium. We have built a cryogenic valved cell suspended from a dilution refrigerator along the axis of a 4T quadrupole magnetic field. The cell is maintained at a base temperature of 100mK. The buffer gas is removed by opening the valve. Any remaining buffer gas may be energetic enough to scatter the atoms out of the trapping potential, thus limiting the lifetime. Therefore, we lower the temperature of the cell to decrease the vapor pressure of any ^3He remaining on the walls. We can mimic the conditions of a 1 μB species using atomic Mn (5 μB) simply by lowering the trapping field strength by a factor of five. Further, we will report on efforts to trap and thermally isolate ^7Li, a true 1 μB species. [1]J. D. Weinstein et al., Phys. Rev. A 57, R3173 (1998).

  15. Quantum dot-induced viral capsid assembling in dissociation buffer

    Directory of Open Access Journals (Sweden)

    Gao D

    2013-06-01

    Full Text Available Ding Gao,1,2 Zhi-Ping Zhang,1 Feng Li,3 Dong Men,1 Jiao-Yu Deng,1 Hong-Ping Wei,1 Xian-En Zhang,1 Zong-Qiang Cui1 1State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 2Graduate University of Chinese Academy of Sciences, Beijing, 3Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, People's Republic of China Abstract: Viruses encapsulating inorganic nanoparticles are a novel type of nanostructure with applications in biomedicine and biosensors. However, the encapsulation and assembly mechanisms of these hybridized virus-based nanoparticles (VNPs are still unknown. In this article, it was found that quantum dots (QDs can induce simian virus 40 (SV40 capsid assembly in dissociation buffer, where viral capsids should be disassembled. The analysis of the transmission electron microscope, dynamic light scattering, sucrose density gradient centrifugation, and cryo-electron microscopy single particle reconstruction experimental results showed that the SV40 major capsid protein 1 (VP1 can be assembled into ≈25 nm capsids in the dissociation buffer when QDs are present and that the QDs are encapsulated in the SV40 capsids. Moreover, it was determined that there is a strong affinity between QDs and the SV40 VP1 proteins (KD = 2.19E-10 M, which should play an important role in QD encapsulation in the SV40 viral capsids. This study provides a new understanding of the assembly mechanism of SV40 virus-based nanoparticles with QDs, which may help in the design and construction of other similar virus-based nanoparticles. Keywords: quantum dots, simian virus 40, self-assembly, encapsulation, virus-based nanoparticles

  16. Photo-induced wettability of TiO{sub 2} film with Au buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam [School of Physics, University of Hyderabad, Hyderabad-500046 (India); Madhurima, V., E-mail: madhurima.v@gmail.com [Department of Physics, Central University of Tamil Nadu, Thiruvarur-610004 (India)

    2014-04-24

    The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

  17. Power-law distributions for a trapped ion interacting with a classical buffer gas.

    Science.gov (United States)

    DeVoe, Ralph G

    2009-02-13

    Classical collisions with an ideal gas generate non-Maxwellian distribution functions for a single ion in a radio frequency ion trap. The distributions have power-law tails whose exponent depends on the ratio of buffer gas to ion mass. This provides a statistical explanation for the previously observed transition from cooling to heating. Monte Carlo results approximate a Tsallis distribution over a wide range of parameters and have ab initio agreement with experiment.

  18. Impact of buffer gas quenching on the 1S0 → 1P1 ground-state atomic transition in nobelium

    NARCIS (Netherlands)

    Chhetri, Premaditya; Ackermann, Dieter; Backe, Hartmut; Block, Michael; Cheal, Bradley; Düllmann, Christoph Emanuel; Even, Julia; Ferrer, Rafael; Giacoppo, Francesca; Götz, Stefan; Heßberger, Fritz Peter; Kaleja, Oliver; Khuyagbaatar, Jadambaa; Kunz, Peter; Laatiaoui, Mustapha; Lautenschläger, Felix; Lauth, Werner; Ramirez, Enrique Minaya; Mistry, Andrew Kishor; Raeder, Sebastian; Wraith, Calvin; Walther, Thomas; Yakushev, Alexander

    2017-01-01

    Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique an optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically

  19. Characterization of atomic spin polarization lifetime of cesium vapor cells with neon buffer gas

    Science.gov (United States)

    Lou, Janet W.; Cranch, Geoffrey A.

    2018-02-01

    The dephasing time of spin-polarized atoms in an atomic vapor cell plays an important role in determining the stability of vapor-cell clocks as well as the sensitivity of optically-pumped magnetometers. The presence of a buffer gas can extend the lifetime of these atoms. Many vapor cell systems operate at a fixed (often elevated) temperature. For ambient temperature operation with no temperature control, it is necessary to characterize the temperature dependence as well. We present a spin-polarization lifetime study of Cesium vapor cells with different buffer gas pressures, and find good agreement with expectations based on the combined effects of wall collisions, spin exchange, and spin destruction. For our (7.5 mm diameter) vapor cells, the lifetime can be increased by two orders of magnitude by introducing Ne buffer gas up to 100 Torr. Additionally, the dependence of the lifetime on temperature is measured (25 - 47 oC) and simulated for the first time to our knowledge with reasonable agreement.

  20. Substrate-induced magnetism in epitaxial graphene buffer layers.

    Science.gov (United States)

    Ramasubramaniam, A; Medhekar, N V; Shenoy, V B

    2009-07-08

    Magnetism in graphene is of fundamental as well as technological interest, with potential applications in molecular magnets and spintronic devices. While defects and/or adsorbates in freestanding graphene nanoribbons and graphene sheets have been shown to cause itinerant magnetism, controlling the density and distribution of defects and adsorbates is in general difficult. We show from first principles calculations that graphene buffer layers on SiC(0001) can also show intrinsic magnetism. The formation of graphene-substrate chemical bonds disrupts the graphene pi-bonds and causes localization of graphene states near the Fermi level. Exchange interactions between these states lead to itinerant magnetism in the graphene buffer layer. We demonstrate the occurrence of magnetism in graphene buffer layers on both bulk-terminated as well as more realistic adatom-terminated SiC(0001) surfaces. Our calculations show that adatom density has a profound effect on the spin distribution in the graphene buffer layer, thereby providing a means of engineering magnetism in epitaxial graphene.

  1. Buffer modulation of menadione-induced oxidative stress in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lushchak, Oleh V; Bayliak, Maria M; Korobova, Olha V; Levine, Rodney L; Lushchak, Volodymyr I

    2009-01-01

    The objective of this study was to compare, in vivo, the effects of bicarbonate and phosphate buffers on survival and menadione-induced oxidative stress in yeast cells. The latter were treated with different concentrations of menadione in the presence of these two buffers. At 25 mM concentration of buffers, menadione only slightly reduced yeast surviving; at 50 mM concentration, cell killing by menadione was much more pronounced in bicarbonate than in phosphate buffer. Although the content of protein carbonyl groups did not show development of oxidative stress under menadione-induced stress, inactivation of aconitase and decrease in glutathione level mirrored its induction. However, cellular glutathione and aconitase activity decrease did not correlate with yeast survival. In vitro, aconitase was more quickly inactivated in 50 mM carbonate, than in 50 mM phosphate buffer. The possible involvement of the carbonate radical in these processes is discussed.

  2. Gas migration in KBS-3 buffer bentonite. Sensitivity of test parameters to experimental boundary conditions

    International Nuclear Information System (INIS)

    Harrington, J.F.; Horseman, S.T.

    2003-01-01

    In the current Swedish repository design concept, hydrogen gas can be generated inside a waste canister by anaerobic corrosion of the ferrous metal liner. If the gas generation rate exceeds the diffusion rate of gas molecules in the buffer porewater, gas will accumulate in the void-space of a canister until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. Three long tenn gas injection tests have been performed on cylinders of pre-compacted MX80 bentonite. Two of these tests were undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. Gas was injected at a centrally located porous filter installed in the clay before hydration. Arrangements were made for gas to flow to three independently monitored sink-filter arrays mounted around the specimen. Axial and radial total stresses and internal porewater pressures were continuously monitored. Breakthrough and peak gas pressures were substantially larger than the sum of the swelling pressure and the external porewater. The third test was performed. using an apparatus which radially constrains the specimen during gas flow. Observed sensitivity of the breakthrough and peak gas pressures to the test boundary conditions suggests that gas entry must be accompanied by dilation of the bentonite fabric. In other words, there is a tendency for the volume of the specimen to increase during this process. The experimental evidence is consistent with the flow of gas along a relatively small number of crack-like pathways which propagate through the clay as gas pressure increases. Gas entry and breakthrough under constant volume boundary conditions causes a substantial increase in the total stress and the internal porewater pressure. It is possible to determine the point at which gas enters the clay by monitoring changes in these parameters. Localisation of gas flow within multiple pathways results, in nonuniform discharge rates at the sinks. When gas injection

  3. Gas migration in KBS-3 buffer bentonite. Sensitivity of test parameters to experimental boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, J.F.; Horseman, S.T. [British Geological Survey, Nottingham (United Kingdom)

    2003-01-01

    In the current Swedish repository design concept, hydrogen gas can be generated inside a waste canister by anaerobic corrosion of the ferrous metal liner. If the gas generation rate exceeds the diffusion rate of gas molecules in the buffer porewater, gas will accumulate in the void-space of a canister until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. Three long tenn gas injection tests have been performed on cylinders of pre-compacted MX80 bentonite. Two of these tests were undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. Gas was injected at a centrally located porous filter installed in the clay before hydration. Arrangements were made for gas to flow to three independently monitored sink-filter arrays mounted around the specimen. Axial and radial total stresses and internal porewater pressures were continuously monitored. Breakthrough and peak gas pressures were substantially larger than the sum of the swelling pressure and the external porewater. The third test was performed. using an apparatus which radially constrains the specimen during gas flow. Observed sensitivity of the breakthrough and peak gas pressures to the test boundary conditions suggests that gas entry must be accompanied by dilation of the bentonite fabric. In other words, there is a tendency for the volume of the specimen to increase during this process. The experimental evidence is consistent with the flow of gas along a relatively small number of crack-like pathways which propagate through the clay as gas pressure increases. Gas entry and breakthrough under constant volume boundary conditions causes a substantial increase in the total stress and the internal porewater pressure. It is possible to determine the point at which gas enters the clay by monitoring changes in these parameters. Localisation of gas flow within multiple pathways results, in nonuniform discharge rates at the sinks. When gas injection

  4. Buffer gas cooling of ions stored in an R.F. trap: Computed properties of the ionic cloud

    International Nuclear Information System (INIS)

    Alili, A.; Andre, J.; Vedel, F.

    1988-01-01

    The spatial and energetic properties of an ion cloud confined in an RF quadrupole trap, together with the lifetimes of the confined ions, have been computed by statistical methods and recently by a simulation method. The influences of different parameters such as ion mass, buffer gas mass, working point in the stability diagram, 'weak' space-charge and shape of the velocity distribution of the cooling buffer gas have been investigated and are described. (orig.)

  5. Early age sealing of buffer-rock gap by artificial wetting to induce bentonite swelling

    International Nuclear Information System (INIS)

    Holt, Erika; Marjavaara, Pieti

    2012-01-01

    to quantify the variation of water content, SHORE hardness and density across the buffer and gap filling. The results showed that the bentonite buffer exposed to rapid artificial wetting is able to uniformly swelling to fill the gap within the first day with 25 mm gap. When only a water-filled gap was used, a radial pressure of about 200 kPa was achieved within the first few days with gas-tight steel lid in use. The pressure reached a maximum after about 2 weeks and then gradually declined due to moisture distribution from the gap towards the centre of the buffer block. Radial cracks appeared within the blocks within the test duration, which extended the full depth and across blocks. These could tighten and seal with prolonged testing or water addition. When gap filling materials were used, such as Cebogel pellets or Ibeco Seal granules, the radial pressure had maximum values up to 600 kPa. The pressure developed at a much faster rate and was better maintained over time, without the same type of pressure drop experienced with only an air-water filled gap. It was demonstrated that water could percolate through the pellet filling to be evenly distributed within a few minutes. This was also achieved in longer tube-filling tests simulating actual deposition holes, showing that when the pellets were placed by free-falling there was enough void space to allow full water filtration. The swollen material was well confined in the gap when an axial confining pressure was used from the start of testing. In some cases, the vertical, or axial, uplift pressure due to swelling was as much as double the radial pressure. Yet this could theoretically be counter-balanced by applying a confining load or lid to prevent buffer uplift into the tunnel backfill area. These post-test assessments showed that moisture equilibrium between the gap and buffer was not reached within the short test duration as expected. The outer gap filled material could have water contents on the order of 100 to

  6. Modeling of flowing gas diode pumped alkali lasers: dependence of the operation on the gas velocity and on the nature of the buffer gas.

    Science.gov (United States)

    Barmashenko, B D; Rosenwaks, S

    2012-09-01

    A simple, semi-analytical model of flowing gas diode pumped alkali lasers (DPALs) is presented. The model takes into account the rise of temperature in the lasing medium with increasing pump power, resulting in decreasing pump absorption and slope efficiency. The model predicts the dependence of power on the flow velocity in flowing gas DPALs and checks the effect of using a buffer gas with high molar heat capacity and large relaxation rate constant between the 2P3/2 and 2P1/2 fine-structure levels of the alkali atom. It is found that the power strongly increases with flow velocity and that by replacing, e.g., ethane by propane as a buffer gas the power may be further increased by up to 30%. Eight kilowatt is achievable for 20 kW pump at flow velocity of 20  m/s.

  7. Deprotonation effect of tetrahydrofuran-2-carbonitrile buffer gas dopant in ion mobility spectrometry.

    Science.gov (United States)

    Fernandez-Maestre, Roberto; Meza-Morelos, Dairo; Wu, Ching

    2016-06-15

    When dopants are introduced into the buffer gas of an ion mobility spectrometer, spectra are simplified due to charge competition. We used electrospray ionization to inject tetrahydrofuran-2-carbonitrile (F, 2-furonitrile or 2-furancarbonitrile) as a buffer gas dopant into an ion mobility spectrometer coupled to a quadrupole mass spectrometer. Density functional theory was used for theoretical calculations of dopant-ion interaction energies and proton affinities, using the hybrid functional X3LYP/6-311++(d,p) with the Gaussian 09 program that accounts for the basis set superposition error; analytes structures and theoretical calculations with Gaussian were used to explain the behavior of the analytes upon interaction with F. When F was used as a dopant at concentrations below 1.5 mmol m(-3) in the buffer gas, ions were not observed for α-amino acids due to charge competition with the dopant; this deprotonation capability arises from the production of a dimer with a high formation energy that stabilized the positive charge and created steric hindrance that deterred the equilibrium with analyte ions. F could not completely strip other compounds of their charge because they either showed steric hindrance at the charge site that deterred the approach of the dopant (2,4-lutidine, and DTBP), formed intramolecular bonds that stabilized the positive charge (atenolol), had high proton affinity (2,4-lutidine, DTBP, valinol and atenolol), or were inherently ionic (tetraalkylammonium ions). This selective deprotonation suggests the use of F to simplify spectra of complex mixtures in ion mobility and mass spectrometry in metabolomics, proteomics and other studies that generate complex spectra with thousands of peaks. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Doppler-free laser spectroscopy of buffer-gas-cooled molecular radicals

    International Nuclear Information System (INIS)

    Skoff, S M; Hendricks, R J; Sinclair, C D J; Tarbutt, M R; Hudson, J J; Segal, D M; Sauer, B E; Hinds, E A

    2009-01-01

    We demonstrate Doppler-free saturated absorption spectroscopy of cold molecular radicals formed by laser ablation inside a cryogenic buffer gas cell. By lowering the temperature, congested regions of the spectrum can be simplified, and by using different temperatures for different regions of the spectrum a wide range of rotational states can be studied optimally. We use the technique to study the optical spectrum of YbF radicals with a resolution of 30 MHz, measuring the magnetic hyperfine parameters of the electronic ground state. The method is suitable for high-resolution spectroscopy of a great variety of molecules at controlled temperature and pressure, and is particularly well suited to those that are difficult to produce in the gas phase.

  9. Towards radiation detected resonance ionization spectroscopy on transfermium elements in a buffer gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, 64289 Darmstadt (Germany); Laatiaoui, Mustapha; Block, Michael [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55128 Mainz (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, 55128 Mainz (Germany); Hessberger, Fritz-Peter [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2013-07-01

    The study of the atomic structure of transfermium elements like nobelium (No) and lawrencium (Lr) via Radiation Detected Resonance Ionization Spectroscopy (RADRIS) is one of the most fascinating disciplines of modern atomic physics. It allows the determination of relativistic effects at the heaviest elements and provides a critical test of theoretical predictions. For these transfermium elements no experimental data on atomic level schemes are available at present. First experiments on {sup 254}No were performed in 2007, in which a buffer gas cell with an overall efficiency of 1%. In this experiment the evaporation temperature of nobelium was determined for the first time. To increase the efficiency of the buffer gas cell, off-line measurements have been performed with nat. ytterbium, the chemical homologue of nobelium. Also on-line experiments during a parasitic beam-time in 2012 provided an insight into the critical parameters of our setup. The results of the off-line and on-line measurements are briefly summarized in this talk.

  10. Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

    International Nuclear Information System (INIS)

    Abdullah, S.; Affolderbach, C.; Gruet, F.; Mileti, G.

    2015-01-01

    We report an aging study on micro-fabricated alkali vapor cells using neon as a buffer gas. An experimental atomic clock setup is used to measure the cell's intrinsic frequency, by recording the clock frequency shift at different light intensities and extrapolating to zero intensity. We find a drift of the cell's intrinsic frequency of (−5.2 ± 0.6) × 10 −11 /day and quantify deterministic variations in sources of clock frequency shifts due to the major physical effects to identify the most probable cause of the drift. The measured drift is one order of magnitude stronger than the total frequency variations expected from clock parameter variations and corresponds to a slow reduction of buffer gas pressure inside the cell, which is compatible with the hypothesis of loss of Ne gas from the cell due to its permeation through the cell windows. A negative drift on the intrinsic cell frequency is reproducible for another cell of the same type. Based on the Ne permeation model and the measured cell frequency drift, we determine the permeation constant of Ne through borosilicate glass as (5.7 ± 0.7) × 10 −22 m 2 s −1  Pa −1 at 81 °C. We propose this method based on frequency metrology in an alkali vapor cell atomic clock setup based on coherent population trapping for measuring permeation constants of inert gases

  11. Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J; Latkowski, J

    2010-12-03

    ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.

  12. The extraction of "2"2"9Th"3"+ from a buffer-gas stopping cell

    International Nuclear Information System (INIS)

    Wense, L. von der; Seiferle, B.; Laatiaoui, M.; Thirolf, P.G.

    2016-01-01

    In the whole landscape of atomic nuclei, "2"2"9Th is currently the only known nucleus which could allow for the development of a nuclear-based frequency standard, as it possesses an isomeric state of just 7.6 eV energy above the ground state. The 3+ charge state is of special importance in this context, as Th"3"+ allows for a simple laser-cooling scheme. Here we emphasize the direct extraction of triply-charged "2"2"9Th from a buffer-gas stopping cell. This finding will not only simplify any future approach of "2"2"9Th ion cooling, but is also used for thorium-beam purification and in this way provides a powerful tool for the direct identification of the "2"2"9Th isomer to ground state nuclear transition.

  13. Magnetic trapping of buffer-gas-cooled chromium atoms and prospects for the extension to paramagnetic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Bakker, Joost M [Humboldt Universitaet zu Berlin, Institut fuer Physik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Stoll, Michael [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Weise, Dennis R [Universitaet Konstanz, Fachbereich Physik, 78457 Constance (Germany); Vogelsang, Oliver [Universitaet Konstanz, Fachbereich Physik, 78457 Konstanz (Germany); Meijer, Gerard [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Peters, Achim [Humboldt Universitaet zu Berlin, Institut fuer Physik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2006-10-14

    We report the successful buffer-gas cooling and magnetic trapping of chromium atoms with densities exceeding 10{sup 12} atoms per cm{sup 3} at a temperature of 350 mK for the trapped sample. The possibilities of extending the method to buffer-gas cool and magnetically trap molecules are discussed. To minimize the most important loss mechanism in magnetic trapping, molecules with a small spin-spin interaction and a large rotational constant are preferred. Both the CrH ({sup 6}{sigma}{sup +} ground state) and MnH ({sup 7}{sigma}{sup +}) radicals appear to be suitable systems for future experiments.

  14. Magnetic trapping of buffer-gas-cooled chromium atoms and prospects for the extension to paramagnetic molecules

    International Nuclear Information System (INIS)

    Bakker, Joost M; Stoll, Michael; Weise, Dennis R; Vogelsang, Oliver; Meijer, Gerard; Peters, Achim

    2006-01-01

    We report the successful buffer-gas cooling and magnetic trapping of chromium atoms with densities exceeding 10 12 atoms per cm 3 at a temperature of 350 mK for the trapped sample. The possibilities of extending the method to buffer-gas cool and magnetically trap molecules are discussed. To minimize the most important loss mechanism in magnetic trapping, molecules with a small spin-spin interaction and a large rotational constant are preferred. Both the CrH ( 6 Σ + ground state) and MnH ( 7 Σ + ) radicals appear to be suitable systems for future experiments

  15. F-state quenching with CH4 for buffer-gas cooled 171Y b+ frequency standard

    Directory of Open Access Journals (Sweden)

    Y.-Y. Jau

    2015-11-01

    Full Text Available We report that methane, CH4, can be used as an efficient F-state quenching gas for trapped ytterbium ions. The quenching rate coefficient is measured to be (2.8 ± 0.3 × 106 s−1 Torr−1. For applications that use microwave hyperfine transitions of the ground-state 171Y b ions, the CH4 induced frequency shift coefficient and the decoherence rate coefficient are measured as δν/ν = (−3.6 ± 0.1 × 10−6 Torr−1 and 1/T2 = (1.5 ± 0.2 × 105 s−1 Torr−1. In our buffer-gas cooled 171Y b+ microwave clock system, we find that only ≤10−8 Torr of CH4 is required under normal operating conditions to efficiently clear the F-state and maintain ≥85% of trapped ions in the ground state with insignificant pressure shift and collisional decoherence of the clock resonance.

  16. [Measurement of atomic number of alkali vapor and pressure of buffer gas based on atomic absorption].

    Science.gov (United States)

    Zheng, Hui-jie; Quan, Wei; Liu, Xiang; Chen, Yao; Lu, Ji-xi

    2015-02-01

    High sensitivitymagnetic measurementscanbe achieved by utilizing atomic spinmanipulation in the spin-exchange-relaxation-free (SERF) regime, which uses an alkali cell as a sensing element. The atomic number density of the alkali vapor and the pressure of the buffer gasare among the most important parameters of the cell andrequire accurate measurement. A method has been proposed and developedto measure the atomic number density and the pressure based on absorption spectroscopy, by sweeping the absorption line and fittingthe experiment data with a Lorentzian profile to obtainboth parameters. Due to Doppler broadening and pressure broadening, which is mainly dominated by the temperature of the cell and the pressure of buffer gas respectively, this work demonstrates a simulation of the errorbetween the peaks of the Lorentzian profile and the Voigt profile caused by bothfactors. The results indicates that the Doppler broadening contribution is insignificant with an error less than 0.015% at 313-513 K for a 4He density of 2 amg, and an error of 0.1% in the presence of 0.6-5 amg at 393 K. We conclude that the Doppler broadening could be ignored under above conditions, and that the Lorentzianprofile is suitably applied to fit the absorption spectrumobtainingboth parameters simultaneously. In addition we discuss the resolution and the instability due to thelight source, wavelength and the temperature of the cell. We find that the cell temperature, whose uncertainty is two orders of magnitude larger than the instability of the light source and the wavelength, is one of the main factors which contributes to the error.

  17. Cryogenic buffer-gas loading and magnetic trapping of CrH and MnH molecules

    NARCIS (Netherlands)

    Stoll, M.; Bakker, J. M.; Steimle, T. C.; Meijer, G.; Peters, A.

    2008-01-01

    We report on the buffer- gas cooling and trapping of CrH and MnH molecules in a magnetic quadrupole trap with densities on the order of 10(6) cm(-3) at a temperature of 650 mK. Storage times of up to 180 ms have been observed, corresponding to a 20- fold lifetime enhancement with respect to the

  18. Impact of buffer gas quenching on the 1S0 → 1P1 ground-state atomic transition in nobelium

    International Nuclear Information System (INIS)

    Chhetri, P.; Lautenschlaeger, F.; Ackermann, D.; Backe, H.; Lauth, W.; Block, M.; Duellmann, C.E.; Goetz, S.; Cheal, B.; Wraith, C.; Even, J.; Ferrer, R.; Giacoppo, F.; Hessberger, F.P.; Khuyagbaatar, J.; Kishor Mistry, A.; Raeder, S.; Yakushev, A.; Kaleja, O.; Kunz, P.; Laatiaoui, M.; Minaya Ramirez, E.; Walther, T.

    2017-01-01

    Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique an optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the study of nobelium and beyond, where atomic properties are currently unknown. (authors)

  19. CAST search for sub-eV mass solar axions with $^{3}$He buffer gas

    CERN Document Server

    Aune, S; Belov, A; Borghi, S; Brauninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galan, J; Garcia, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gomez, H; Gruber, E; Guthorl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovcic, K; Karuza, M; Konigsmann, K; Kotthaus, R; Krcmar, M; Kuster, M; Lakic, B; Laurent, J M; Liolios, A; Ljubicic, A; Lozza, V; Lutz, G; Luzon, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodriguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S.K; Stewart, L; Tomas, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-01-01

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV < m_a < 0.64 eV. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 2.3 x 10^{-10} GeV^{-1} at 95% CL, the exact value depending on the pressure setting. KSVZ axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In future we will extend our search to m_a < 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  20. Cryogenic buffer-gas loading and magnetic trapping of CrH and MnH molecules

    OpenAIRE

    Stoll, M.; Bakker, J.; Steimle, T.; Meijer, G.; Peters, A.

    2008-01-01

    We report on the buffer-gas cooling and trapping of CrH and MnH molecules in a magnetic quadrupole trap with densities on the order of 106 cm−3 at a temperature of 650 mK. Storage times of up to 180 ms have been observed, corresponding to a 20-fold lifetime enhancement with respect to the field-free diffusion through the 3He buffer-gas. Using Monte Carlo trajectory simulations, inelastic molecule-3He collision cross sections of 1.6×10−18 and 3.1×10−17 cm2 are extracted for CrH and MnH, respec...

  1. Modelling and analysis of canister and buffer for earthquake induced rock shear and glacial load

    International Nuclear Information System (INIS)

    Hernelind, Jan

    2010-08-01

    Existing fractures crossing a deposition hole may be activated and sheared by an earthquake. The effect of such a rock shear has been investigated by finite element calculations. The buffer material in a deposition hole acts as a cushion between the canister and the rock, which reduces the effect of a rock shear substantially. Lower density of the buffer yields softer material and reduced effect on the canister. However, at the high density that is suggested for a repository the stiffness of the buffer is rather high. The stiffness is also a function of the rate of shear, which means that there may be a substantial damage on the canister at very high shear rates. However, the earthquake induced rock shear velocity is lower than 1 m/s which is not considered to be very high. The rock shear has been modelled with finite element calculations with the code Abaqus. A three dimensional finite element mesh of the buffer and the canister has been created and simulation of a rock shear has been performed. The rock shear has been assumed to take place either perpendicular to the canister at the quarter point or at an inclined angle of 22.5 deg in tension. Furthermore horizontal shear has been studied using a vertical shear plane either at the centre or at 1/4-point for the canister. The shear calculations have been driven to a total shear of 10 cm. The canister also has to be designed to withstand the loads caused by a thick ice sheet. Besides rock shear the model has been used to analyse the effect of such glacial load (either combined with rock shear or without rock shear). This report also summarizes the effect when considering creep in the copper shell

  2. Modelling and analysis of canister and buffer for earthquake induced rock shear and glacial load

    Energy Technology Data Exchange (ETDEWEB)

    Hernelind, Jan (5T Engineering AB (Sweden))

    2010-08-15

    Existing fractures crossing a deposition hole may be activated and sheared by an earthquake. The effect of such a rock shear has been investigated by finite element calculations. The buffer material in a deposition hole acts as a cushion between the canister and the rock, which reduces the effect of a rock shear substantially. Lower density of the buffer yields softer material and reduced effect on the canister. However, at the high density that is suggested for a repository the stiffness of the buffer is rather high. The stiffness is also a function of the rate of shear, which means that there may be a substantial damage on the canister at very high shear rates. However, the earthquake induced rock shear velocity is lower than 1 m/s which is not considered to be very high. The rock shear has been modelled with finite element calculations with the code Abaqus. A three dimensional finite element mesh of the buffer and the canister has been created and simulation of a rock shear has been performed. The rock shear has been assumed to take place either perpendicular to the canister at the quarter point or at an inclined angle of 22.5 deg in tension. Furthermore horizontal shear has been studied using a vertical shear plane either at the centre or at 1/4-point for the canister. The shear calculations have been driven to a total shear of 10 cm. The canister also has to be designed to withstand the loads caused by a thick ice sheet. Besides rock shear the model has been used to analyse the effect of such glacial load (either combined with rock shear or without rock shear). This report also summarizes the effect when considering creep in the copper shell

  3. Nonthermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with gas-liquid porous metal contractor

    Science.gov (United States)

    This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO2) system, with a gas-liquid CO2 contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO2 system at CO2 con...

  4. Energy distributions of an ion in a radio-frequency trap immersed in a buffer gas under the influence of additional external forces

    Science.gov (United States)

    Rouse, I.; Willitsch, S.

    2018-04-01

    An ion held in a radio-frequency trap interacting with a uniform buffer gas of neutral atoms develops a steady-state energy distribution characterized by a power-law tail at high energies instead of the exponential decay characteristic of thermal equilibrium. We have previously shown that the Tsallis statistics frequently used as an empirical model for this distribution is a good approximation when the ion is heated due to a combination of micromotion interruption and exchange of kinetic energy with the buffer gas [Rouse and Willitsch, Phys. Rev. Lett. 118, 143401 (2017), 10.1103/PhysRevLett.118.143401]. Here, we extend our treatment to include the heating due to additional motion of the ion caused by external forces, including the "excess micromotion" induced by uniform electric fields and rf phase offsets. We show that this also leads to a Tsallis distribution with a potentially different power-law exponent from that observed in the absence of this additional forced motion, with the difference increasing as the ratio of the mass of the neutral atoms to that of the ion decreases. Our results indicate that unless the excess micromotion is minimized to a very high degree, then even a system with very light neutrals and a heavy ion does not exhibit a thermal distribution.

  5. Note: Buffer gas temperature inhomogeneities and design of drift-tube ion mobility spectrometers: Warnings for real-world applications by non-specialists

    Science.gov (United States)

    Fernandez-Maestre, R.

    2017-09-01

    Ion mobility spectrometry (IMS) separates gas phase ions moving under an electric field according to their size-to-charge ratio. IMS is the method of choice to detect illegal drugs and explosives in customs and airports making accurate determination of reduced ion mobilities (K0) important for national security. An ion mobility spectrometer with electrospray ionization coupled to a quadrupole mass spectrometer was used to study uncertainties in buffer gas temperatures during mobility experiments. Differences up to 16°C were found in the buffer gas temperatures in different regions of the drift tube and up to 42°C between the buffer gas and the drift tube temperatures. The drift tube temperature is used as an approximation to the buffer gas temperature for the calculation of K0 because the buffer gas temperature is hard to measure. This is leading to uncertainties in the determination of K0 values. Inaccurate determination of K0 values yields false positives that delay the cargo and passengers in customs and airports. Therefore, recommendations are issued for building mobility tubes to assure a homogeneous temperature of the buffer gas. Because the temperature and other instrumental parameters are difficult to measure in IMS, chemical standards should always be used when calculating K0. The difference of 42°C between the drift tube and buffer gas temperatures found in these experiments produces a 10.5% error in the calculation of K0. This large inaccuracy in K0 shows the importance of a correct temperature measurement in IMS.

  6. Electron beam-induced radiation damage: the bubbling response in amorphous dried sodium phosphate buffer.

    Science.gov (United States)

    Massover, William H

    2010-06-01

    Irradiation of an amorphous layer of dried sodium phosphate buffer (pH = 7.0) by transmission electron microscopy (100-120 kV) causes rapid formation of numerous small spherical bubbles [10-100 A (= 1-10 nm)] containing an unknown gas. Bubbling is detected even with the first low-dose exposure. In a thin layer (ca. 100-150 A), bubbling typically goes through nucleation, growth, possible fusion, and end-state, after which further changes are not apparent; co-irradiated adjacent areas having a slightly smaller thickness never develop bubbles. In moderately thicker regions (ca. over 200 A), there is no end-state. Instead, a complex sequence of microstructural changes is elicited during continued intermittent high-dose irradiation: nucleation, growth, early simple fusions, a second round of extensive multiple fusions, general reduction of matrix thickness (producing flattening and expansion of larger bubbles, occasional bubble fission, and formation of very large irregularly-shaped bubbles by a third round of compound fusion events), and slow shrinkage of all bubbles. The ongoing lighter appearance of bubble lumens, maintenance of their rounded shape, and extensive changes in size and form indicate that gas content continues throughout their surprisingly long lifetime; the thin dense boundary layer surrounding all bubbles is proposed to be the main mechanism for their long lifetime.

  7. Cryogenic buffer-gas loading and magnetic trapping of CrH and MnH molecules

    Science.gov (United States)

    Stoll, Michael; Bakker, Joost M.; Steimle, Timothy C.; Meijer, Gerard; Peters, Achim

    2008-09-01

    We report on the buffer-gas cooling and trapping of CrH and MnH molecules in a magnetic quadrupole trap with densities on the order of 106cm-3 at a temperature of 650mK . Storage times of up to 180ms have been observed, corresponding to a 20-fold lifetime enhancement with respect to the field-free diffusion through the He3 buffer-gas. Using Monte Carlo trajectory simulations, inelastic molecule- He3 collision cross sections of 1.6×10-18 and 3.1×10-17cm2 are extracted for CrH and MnH, respectively. Furthermore, elastic molecule- He3 collision cross sections of 1.4(±0.5)×10-14cm2 are determined for both species. We conclude that the confinement time of these molecules in a magnetic trapping field is limited by inelastic collisions with the helium atoms leading to Zeeman relaxation.

  8. Investigations on the carbon contaminations on the alkali cells of DPAL with hydrocarbon buffer gas

    Science.gov (United States)

    Li, Zhiyong; Tan, Rongqing; Wang, Yujie; Ye, Qing; Bian, Jintian; Huang, Wei; Li, Hui; Han, Gaoce

    2017-10-01

    Diode pumped alkali laser (DPAL) with hydrocarbon buffer gases has the features of low threshold and high efficiency. The chemical reaction between alkali and hydrocarbon gases affects the life time of DPAL. In this paper, a method based on Fourier transform infrared spectroscopy and Lambert-Beer law is adopted to find a safe temperature at which DPAL runs for a long term. A theoretical model is established to figure out ways to reduce the peak temperature in the cell window. The results indicates that 170 °C is a safe temperature. Although the absorbance of the cell window to the pump light and alkali laser is lower, there is temperature increase. Small light-transmitting area and air blowing on the windows can reduce the peak temperature effectively. Cooling the cell window is essential and critical in a long-term running DPAL.

  9. Development of a buffer gas trap for the confinement of positrons and study of positronium production in the GBAR experiment

    CERN Document Server

    AUTHOR|(CDS)2101248; van der Werf, Dirk

    The GBAR experiment relies on the production of antihydrogen positive ions to achieve its goal of measuring the gravitational acceleration of antimatter at rest. The ANTION project, included in the GBAR enterprise, is responsible for the production of these antimatter ions. Moreover, it also aims to measure the cross section of antihydrogen production throughout the collision of antiprotons and positronium atoms, as well as the matter cross sections of hydrogen and the hydrogen negative ion. These experiments imply the formation of a very dense positronium cloud, thus a large amount of positrons will be implanted on a positron/positronium converter material. This thesis reports the construction of a three stage buffer gas trap with the goal of trapping and accumulating positrons for the ANTION project. The combination of the Penning-type trap with a LINAC source constitutes a unique experimental setup. The trap was commissioned and optimized and is now fully operational. Trapping protocols were studied and...

  10. A pyruvate-buffered dialysis fluid induces less peritoneal angiogenesis and fibrosis than a conventional solution

    NARCIS (Netherlands)

    van Westrhenen, Roos; Zweers, Machteld M.; Kunne, Cindy; de Waart, Dirk R.; van der Wal, Allard C.; Krediet, Raymond T.

    2008-01-01

    BACKGROUND: Conventional lactate-buffered peritoneal dialysis (PD) fluids containing glucose and glucose degradation products are believed to contribute to the development of fibrosis and angiogenesis in the dialyzed peritoneum. To reduce potential negative effects of lactate, pyruvate was

  11. Evaluation of stainless steel cathodes and a bicarbonate buffer for hydrogen production in microbial electrolysis cells using a new method for measuring gas production

    KAUST Repository

    Ambler, Jack R.; Logan, Bruce E.

    2011-01-01

    Microbial electrolysis cells (MECs) are often examined for hydrogen production using non-sustainable phosphate buffered solutions (PBS), although carbonate buffers have been shown to work in other bioelectrochemical systems with a platinum (Pt) catalyst. Stainless steel (SS) has been shown to be an effective catalyst for hydrogen evolution in MECs, but it has not been tested with carbonate buffers. We evaluated the combined using of SS cathodes and a bicarbonate buffer (BBS) at the applied voltages of 0.5, 0.7 and 0.9 V using a new inexpensive method for measuring gas production called the gas bag method (GBM). This method achieved an average error of only 5.0% based on adding known volumes of gas to the bag. Using the GBM, hydrogen production with SS and a BBS was 26.6 ± 1.8 mL which compared well to 26.4 ± 2.8 mL using Pt and BBS, and 26.8 ± 2.5 mL with a Pt cathode and PBS. Electrical energy efficiency was highest with a SS cathode and BBS at 159 ± 17%, compared to 126 ± 14% for the Pt cathode and BBS, and 134 ± 17% for a Pt cathode and PBS. The main disadvantage of the SS was a lower gas production rate of 1.1 ± 0.3 m3 H2-m-3 d-1 with BBS and 1.2 ± 0.3 m3 H2-m-3 d -1 with PBS, compared to 1.7 ± 0.4 m3 H 2-m-3 d-1 with Pt and PBS. These results show that the GBM is an effective new method for measuring gas production of anaerobic gas production processes, and that SS and bicarbonate buffers can be used to effectively produce hydrogen in MECs. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

  12. A novel contra propagating ultrasonic flowmeter using glad buffer rods for high temperature measurement. Application to the oil and gas industries

    Energy Technology Data Exchange (ETDEWEB)

    Franca, Demartonne R. [Brasilia Univ., DF (Brazil). Dept. de Engenharia Eletrica; Cheng-Kuei Jen; Yuu Ono [National Research Council (NRC), Quebec (Canada). Industrial Materials Institute

    2005-07-01

    Ultrasonic techniques are attractive for process monitoring and control because they are non-intrusive, robust and inexpensive. Two common concerns limiting the high temperature performance of conventional ultrasonic systems for flow measurement are related to transducers and couplants. A suitable approach to overcoming this drawback is to insert a thermal isolating buffer rod with good ultrasonic performance (e.g., high signal-to-noise ratio). This requirement is important because, a priori, the noises generated in the buffer rod may bury the desired signals, so that no meaningful information is extracted. Besides protecting the ultrasonic transducers from overheating in applications such as high temperature flow measurements, buffer rods are also a solution for the couplant between the probe and tested sample, since their probing end can be directly wetted by fluids. Here, we propose clad buffer rods driven by shear transducers as the main building block of contra propagating ultrasonic flowmeters for high temperature application. It is demonstrated that the superior signal-to-noise ratio exhibit by clad buffer rods compared to the reported non-clad counterparts improve precision in transit-time measurement, leading to more accurate flow speed determination. In addition, it is shown that clad buffer rods generate specific ultrasonic signals for temperature calibration of flowmeters, allowing temperature variation while still measuring accurately the flow speed. These results are of interest for the oil and gas industries. (author)

  13. Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gómez, H; Gruber, E; Guthörl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Laurent, J M; Liolios, A; Ljubičić, A; Lozza, V; Lutz, G; Luzón, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-12-23

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  14. Adverse postresuscitation myocardial effects elicited by buffer-induced alkalemia ameliorated by NHE-1 inhibition in a rat model of ventricular fibrillation.

    Science.gov (United States)

    Lamoureux, Lorissa; Radhakrishnan, Jeejabai; Mason, Thomas G; Kraut, Jeffrey A; Gazmuri, Raúl J

    2016-11-01

    Major myocardial abnormalities occur during cardiac arrest and resuscitation including intracellular acidosis-partly caused by CO 2 accumulation-and activation of the Na + -H + exchanger isoform-1 (NHE-1). We hypothesized that a favorable interaction may result from NHE-1 inhibition during cardiac resuscitation followed by administration of a CO 2 -consuming buffer upon return of spontaneous circulation (ROSC). Ventricular fibrillation was electrically induced in 24 male rats and left untreated for 8 min followed by defibrillation after 8 min of cardiopulmonary resuscitation (CPR). Rats were randomized 1:1:1 to the NHE-1 inhibitor zoniporide or vehicle during CPR and disodium carbonate/sodium bicarbonate buffer or normal saline (30 ml/kg) after ROSC. Survival at 240 min declined from 100% with Zoniporide/Saline to 50% with Zoniporide/Buffer and 25% with Vehicle/Buffer (P = 0.004), explained by worsening postresuscitation myocardial dysfunction. Marked alkalemia occurred after buffer administration along with lactatemia that was maximal after Vehicle/Buffer, attenuated by Zoniporide/Buffer, and minimal with Zoniporide/Saline [13.3 ± 4.8 (SD), 9.2 ± 4.6, and 2.7 ± 1.0 mmol/l; P ≤ 0.001]. We attributed the intense postresuscitation lactatemia to enhanced glycolysis consequent to severe buffer-induced alkalemia transmitted intracellularly by an active NHE-1. We attributed the worsened postresuscitation myocardial dysfunction also to severe alkalemia intensifying Na + entry via NHE-1 with consequent Ca 2+ overload injuring mitochondria, evidenced by increased plasma cytochrome c Both buffer-induced effects were ameliorated by zoniporide. Accordingly, buffer-induced alkalemia after ROSC worsened myocardial function and survival, likely through enhancing NHE-1 activity. Zoniporide attenuated these effects and uncovered a complex postresuscitation acid-base physiology whereby blood pH drives NHE-1 activity and compromises mitochondrial function and integrity along

  15. Study of the influence of Nb buffer layer on the exchange coupling induced at the Co/IrMn interface

    Energy Technology Data Exchange (ETDEWEB)

    Merino, I.L.C., E-mail: isabel5cas@gmail.com [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro 22290-180 (Brazil); Figueiredo, L.C. [Instituto de Física, Universidade de Brasília, Brasília 70910-900 (Brazil); Passamani, E.C.; Nascimento, V.P. [Departamento de Física, Universidade Federal do Espírito Santo, Vitória 29075-910 (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, Goiânia 74560-900 (Brazil); Baggio Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro 22290-180 (Brazil)

    2017-06-15

    Highlights: • Nb buffer layer favors smooth/rough Co/IrMn interfaces, depending on its thickness. • Double and single-like hysteresis loop features depend on the Nb thickness. • Co uniaxial anisotropy induced exchange-bias in as-deposited sample. • Uniaxial and exchange-bias anisotropy directions depend on the Nb thickness. • Thicker Nb favors non-collinear anisotropies, while thinner Nb favors collinear. - Abstract: Hybrid Nb(t{sub Nb})/Co(10 nm)/IrMn(15 nm)/Nb(10 nm) heterostructured materials were prepared by DC Magnetron Sputtering and systematically studied by X-ray, magnetization and ferromagnetic resonance techniques. For thinner Nb buffer layer (≤10 nm), it was found that there is an inter-diffusion at Co/IrMn interface, which favors double-like hysteresis loop. For thicker Nb layers, however, a gradual transition from double to single-like hysteresis loops is observed and it is associated with the reduction of the Nb roughness, which also enhances the exchange coupling at the Co/IrMn interface. Nb grown on IrMn layer induces the formation of an NbIrMn alloy layer, while no evidence of inter-diffusion at the Co/Nb interface is observed. For rougher Nb buffer layers (t{sub Nb} < 50 nm), exchange bias and Co uniaxial anisotropies are pointing at the same direction (β∼zero), but for smoother Nb buffer layer (t{sub Nb} = 50 nm) a β angle of 150{sup o} is found. Exchange bias effect was measured in as-prepared and in field-cooled samples; being its presence, in as-prepared sample, attributed to the unidirectional anisotropy of the Co layer (its intensity is modified in case of sample with a CoIrMn alloy layer). Considering that the Si/Nb/Co/IrMn interfaces have different β values (t{sub Nb} = 35 and 50 nm), a study of the influence of magnetization direction, governed by exchange-biased layers, on superconducting properties of Nb films can be successfully done in this hybrid system.

  16. Laser-induced gas plasma machining

    Energy Technology Data Exchange (ETDEWEB)

    Elhadj, Selim; Bass, Isaac Louis; Guss, Gabriel Mark; Matthews, Manyalibo J.

    2017-10-17

    Techniques for removing material from a substrate are provided. A laser beam is focused at a distance from the surface to be treated. A gas is provided at the focus point. The gas is dissociated using the laser energy to generate gas plasma. The substrate is then brought in contact with the gas plasma to enable material removal.

  17. Experimental and numerical study of the chemical composition of WSex thin films obtained by pulsed laser deposition in vacuum and in a buffer gas atmosphere

    International Nuclear Information System (INIS)

    Grigoriev, S.N.; Fominski, V.Yu.; Gnedovets, A.G.; Romanov, R.I.

    2012-01-01

    WSe x thin films were obtained by pulsed laser deposition in vacuum and at various Ar gas pressures up to 10 Pa. Stoichiometry and chemical state of the WSe x films were studied by means of Rutherford backscattering spectrometry and X-ray photoelectron spectroscopy. In the case of pulsed laser deposition of WSe x films in vacuum the value of stoichiometric coefficient x was 1.3. During the deposition in argon at pressures of 2-10 Pa the value of x varied from 1.5 to 2.2. To explain the influence of the buffer gas, a model was used that takes into account the following processes: (1) congruent pulsed laser evaporation of the WSe 2.2 target; (2) scattering of laser-evaporated W and Se atoms in Ar; (3) sputtering of the deposited film by high-energy atoms from the laser plume. Experimentally, the velocity distributions of laser-evaporated W and Se atoms in vacuum were determined by the time-of-flight measurements. Collision Monte Carlo simulations were used to quantify the impact of the buffer gas on the energy and the incidence angle distributions of the deposited W and Se atoms. Model distributions were used to determine the chemical composition of the WSe x films, depending on the efficiency of the preferential sputtering of Se atoms.

  18. Development of a equipment to measure gas transport properties: Application to study candidate buffer mixtures for low-medium level waste repositories

    International Nuclear Information System (INIS)

    Martin, P. L.; Barcala, J. M.; Oller, J. C.

    2002-01-01

    This report describes the design, the construction and a testing of a system set-up for the measurement of gas transport, created at CIEMAT, and its application to study mixtures of candidate buffer materials for Low-Medium Level Waste Repertories. The measure of the gas flows is carried on by mass flow meters of several ranges, white the pressure of the applied within the sample is controlled. Two National l Instrument's acquisition system that permits the control and recording of the parameters. A specific application developed for this test, with National Instruments LabWIEW DSC, permits to mange the system. A client interface lets to follow the experiment course from a remote location through Internet. (Author) 21 refs

  19. Development of a Equipment to Measure Gas Transport Properties: Application to Study Mixtures of Candidates Buffer Materials for Low-Medium Level Waste Repositories

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P.L.; Barcala, J.M.; Oller, J.C.

    2002-07-01

    This report describes the design, the construction and a testing of a system set-up for the measurement of gas transport, created at CIEMAT, and its application to study mixtures of candidate buffer materials for Low-Medium Level Waste Repertories. The measure of the gas flows is carried on by mass flow meters of several ranges, white the pressure of the applied within the sample is controlled. Two National l Instrument's acquisition system that permits the control and recording of the parameters. A specific application developed for this test, with National Instruments LabWIEW DSC, permits to mange the system. A client interface lets to follow the experiment course from a remote location through Internet. (Author) 21 refs.

  20. Magnetic two-dimensional electron gas at the manganite-buffered LaAlO3/SrTiO3 interface

    DEFF Research Database (Denmark)

    R. Zhang, H.; Zhang, Y.; Zhang, H.

    2017-01-01

    Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO3/SrTiO3 interface, stemming from the magnetic ordering of Ti3+ ions with the mediat......Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO3/SrTiO3 interface, stemming from the magnetic ordering of Ti3+ ions...... with the mediation of itinerant electrons. Herein, we report a magnetic 2DEG at a La7/8Sr1/8MnO3-buffered LaAlO3/SrTiO3 interface, which simultaneously shows electrically tunable anomalous Hall effect and high conductivity. The spin-polarized temperature for the 2DEG is promoted to 30 K while the mobility remains...... high. The magnetism likely results from a gradient manganese interdiffusion into SrTiO3. The present work demonstrates the great potential of manganite-buffered LaAlO3/SrTiO3 interfaces for spintronic applications....

  1. Detection of Greenhouse-Gas-Induced Climatic Change

    Energy Technology Data Exchange (ETDEWEB)

    Jones, P.D.; Wigley, T.M.L.

    1998-05-26

    The objective of this report is to assemble and analyze instrumental climate data and to develop and apply climate models as a basis for (1) detecting greenhouse-gas-induced climatic change, and (2) validation of General Circulation Models.

  2. The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-Induced Lysine Acetylation of Mitochondrial Proteins

    Directory of Open Access Journals (Sweden)

    Michael N. Davies

    2016-01-01

    Full Text Available Lysine acetylation (AcK, a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis, we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT, an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK.

  3. Radioactively induced noise in gas-sampling uranium calorimeters

    International Nuclear Information System (INIS)

    Gordon, H.A.; Rehak, P.

    1982-01-01

    The signal induced by radioactivity of a U 238 absorber in a cell of a gas-sampling uranium calorimeter was studied. By means of Campbell's theorem, the levels of the radioactively induced noise in uranium gas-sampling calorimeters was calculated. It was shown that in order to obtain similar radioactive noise performance as U-liquid argon or U-scintillator combinations, the α-particles from the uranium must be stopped before entering the sensing volume of gas-uranium calorimeters

  4. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Lang, P M; Laurent, J M; Liolios, A; Ljubičić, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2014-03-07

    The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  5. NH2- in a cold ion trap with He buffer gas: Ab initio quantum modeling of the interaction potential and of state-changing multichannel dynamics

    Science.gov (United States)

    Hernández Vera, Mario; Yurtsever, Ersin; Wester, Roland; Gianturco, Franco A.

    2018-05-01

    We present an extensive range of accurate ab initio calculations, which map in detail the spatial electronic potential energy surface that describes the interaction between the molecular anion NH2 - (1A1) in its ground electronic state and the He atom. The time-independent close-coupling method is employed to generate the corresponding rotationally inelastic cross sections, and then the state-changing rates over a range of temperatures from 10 to 30 K, which is expected to realistically represent the experimental trapping conditions for this ion in a radio frequency ion trap filled with helium buffer gas. The overall evolutionary kinetics of the rotational level population involving the molecular anion in the cold trap is also modelled during a photodetachment experiment and analyzed using the computed rates. The present results clearly indicate the possibility of selectively detecting differences in behavior between the ortho- and para-anions undergoing photodetachment in the trap.

  6. Determination of the extraction efficiency for {sup 233}U source α-recoil ions from the MLL buffer-gas stopping cell

    Energy Technology Data Exchange (ETDEWEB)

    Wense, Lars v.d.; Seiferle, Benedict; Thirolf, Peter G. [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Laatiaoui, Mustapha [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany)

    2015-03-01

    Following the α decay of {sup 233}U, {sup 229}Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass purification efficiency for {sup 229}Th{sup 3+} is determined via MCP-based measurements and via the direct detection of the {sup 229}Th α decay. A large value of (10±2)% for the combined extraction and mass purification efficiency of {sup 229}Th{sup 3+} is obtained at a mass resolution of about 1u/e. In addition to {sup 229}Th, also other α-recoil ions of the {sup 233,} {sup 232}U decay chains are addressed. (orig.)

  7. Search for Solar Axions by the CERN Axion Solar Telescope with 3 He Buffer Gas: Closing the Hot Dark Matter Gap

    CERN Document Server

    Arik, M.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J.M.; Cetin, S.A.; Collar, J.I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J.A.; Gardikiotis, A.; Garza, J.G.; Gazis, E.N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M.D.; Hoffmann, D.H.H.; Iguaz, F.J.; Irastorza, I.G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Krčmar, M.; Kuster, M.; Lakić, B.; Lang, P.M.; Laurent, J.M.; Liolios, A.; Ljubičić, A.; Lozza, V.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P.S.; Solanki, S.K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J.K.; Yildiz, S.C.; Zioutas, K.

    2014-01-01

    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.

  8. Search for Solar Axions by the CERN Axion Solar Telescope with He3 Buffer Gas: Closing the Hot Dark Matter Gap

    Science.gov (United States)

    Arik, M.; Aune, S.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J. M.; Cetin, S. A.; Collar, J. I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J. A.; Gardikiotis, A.; Garza, J. G.; Gazis, E. N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M. D.; Hoffmann, D. H. H.; Iguaz, F. J.; Irastorza, I. G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Krčmar, M.; Kuster, M.; Lakić, B.; Lang, P. M.; Laurent, J. M.; Liolios, A.; Ljubičić, A.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P. S.; Solanki, S. K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J. K.; Yildiz, S. C.; Zioutas, K.; CAST Collaboration

    2014-03-01

    The CERN Axion Solar Telescope has finished its search for solar axions with He3 buffer gas, covering the search range 0.64 eV≲ma≲1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ≲3.3×10-10 GeV-1 at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  9. Buffers Plus

    Science.gov (United States)

    Ramette, Richard W.

    1998-11-01

    In 1989 JCE Software published The Acid-Base Package: A Collection of Useful Programs for Proton Transfer Systems (Ramette, R. W. J. Chem. Educ. Software 1989, 2B No. 2). This DOS program has been fully upgraded by the same author to the world of Windows 95. Buffers Plus takes advantage of a modern user interface and offers many new options not possible in the original version.

  10. Buffer fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M

    1979-08-30

    A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.

  11. An experimental investigation on the properties of laser-induced plasma emission spectra

    International Nuclear Information System (INIS)

    Tang Xiaoshuan; Li Chunyan; Ji Xuehan; Feng Eryin; Cui Zhifeng

    2004-01-01

    The authors have measured the time-resolved emission spectra produced by Nd: YAG laser induced Al plasma with different kinds of buffer gas (He, Ar, N 2 and Air). The dependence of emission spectra line intensity and Stark broadening on the time delay, kinds and pressure of buffer gas are studied. The results show that the atomic emission line intensity reaches maximum at 3 μs time delay, the Stark broadening increases with increasing the pressure of buffer gas, and decreases with increasing time delay. The Stark broadening in Ar buffer gas is largest among the four different kinds of buffer gas. (author)

  12. Yield of radiation-induced DNA single-strand breaks in Escherichia coli and superinfecting phage lambda at different dose rates. Repair of strand breaks in different buffers

    International Nuclear Information System (INIS)

    Boye, E.; Johansen, I.; Brustad, T.

    1976-01-01

    Cells of E. coli K-12 strain AB 1886 were irradiated in oxygenated phosphate buffered saline at 2 0 C with electrons from a 4-MeV linear accelerator. The yield of DNA single-strand breaks was determined as a function of the dose rate between 2.5 and 21,000 krad/min. For dose rates over 100 krad/min the yield was found to be constant. Below 10 krad/min the yield of breaks decreases drastically. This is explained by rejoining of breaks during irradiation. Twenty percent of the breaks induced by acute exposure are repaired within 3 min at 2 0 C. Superinfecting phage lambda DNA is repaired at the same rate as chromosomal DNA. In contrast to the results obtained with phosphate-buffered saline, an increase in the number of breaks after irradiation is observed when the bacteria are suspended in tris buffer. It is suggested that buffers of low ionic strength facilitate the leakage through the membrane of a small-molecular-weight component(s) necessary for DNA strand rejoining

  13. Buffer-gas cooling of antiprotonic helium to 1.5 to 1.7 K, and antiproton-to–electron mass ratio

    CERN Document Server

    Hori, Masaki; Sótér, Anna; Barna, Daniel; Dax, Andreas; Hayano, Ryugo; Kobayashi, Takumi; Murakami, Yohei; Todoroki, Koichi; Yamada, Hiroyuki; Horváth, Dezső; Venturelli, Luca

    2016-01-01

    Charge, parity, and time reversal (CPT) symmetry implies that a particle and its antiparticle have the same mass. The antiproton-to-electron mass ratio Embedded Image can be precisely determined from the single-photon transition frequencies of antiprotonic helium. We measured 13 such frequencies with laser spectroscopy to a fractional precision of 2.5 × 10−9 to 16 × 10−9. About 2 × 109 antiprotonic helium atoms were cooled to temperatures between 1.5 and 1.7 kelvin by using buffer-gas cooling in cryogenic low-pressure helium gas; the narrow thermal distribution led to the observation of sharp spectral lines of small thermal Doppler width. The deviation between the experimental frequencies and the results of three-body quantum electrodynamics calculations was reduced by a factor of 1.4 to 10 compared with previous single-photon experiments. From this, Embedded Image was determined as 1836.1526734(15), which agrees with a recent proton-to-electron experimental value within 8 × 10−10.

  14. Can Mustard Gas Induce Late Onset Polyneuropathy?

    Directory of Open Access Journals (Sweden)

    SJ. Mousavi

    2007-11-01

    Full Text Available Background:Mustard gas, lethal in high doses, affects multiple organs such as skin, eye and respiratory system. We studied the development of late onset mustardinduced polyneuropathy among chemically wounded Iranian veterans.Methods:In this descriptive study,100 chemically wounded Iranian veterans with severe eye involvement were examined for any signs and symptoms of polyneuropathy by an internist.20 patients were suspected to have neurological symptoms or signs.These patients were examined by a neurologist again. 13 showed abnormal neurological symptoms. Electrodiagnostic exams were performed for this group by another physician.Results:13 veterans had abnormal neurological exam results with prominent sensory signs and symptoms in almost all of them. Brisk deep tendon reflexes were found in 3 cases. Electrodiagnostic studies were compatible with axonal type distal sensory polyneuropathy in 6 subjects. Conclusion: To the best of our knowledge, this is the first report of late onset polyneuropathy among chemically-wounded victims who were exposed to mustard gas. The pathophysiology of this form of neuropathy is still unknown. Unlike most toxic neuropathies,obvious clinical signs and symptoms appeared several years after exposure. No specific treatment for.polyneuropathy due to chemical weapons exposure has been described to date.

  15. Gas induced fire and explosion frequencies

    International Nuclear Information System (INIS)

    Coutts, D.A.

    1997-01-01

    The use and handling of flammable gases poses a fire and explosion hazard to many DOE nuclear facilities. This hazard is not unique to DOE facilities. Each year over 2,900 non-residential structural fires occur in the U.S. where a gas is the first item ignited. Details from these events are collected by the National Fire Incident Reporting System (NFIRS) through an extensive reporting network. This extensive data set (800,000 fires in non-residential structures over a 5-year period) is an underutilized resource within the DOE community. Explosions in nuclear facilities can have very severe consequences. The explosion can both damage the facility containment and provide a mechanism for significant radiological dispersion. In addition, an explosion can have significant worker safety implications. Because of this a quantitative frequency estimate for explosions in an SRS laboratory facility has been prepared using the NFIRS data. 6 refs., 1 tab

  16. Detection of greenhouse-gas-induced climatic change

    International Nuclear Information System (INIS)

    Wigley, T.M.L.; Jones, P.D.

    1992-01-01

    The aims of the US Department of Energy's Carbon Dioxide Research Program are to improve assessments of greenhouse-gas-induced climatic change and to define and reduce uncertainties through selected research. This project will address: The regional and seasonal details of the expected climatic changes; how rapidly will these changes occur; how and when will the climatic effects of CO 2 and other greenhouse gases be first detected; and the relationships between greenhouse-gas-induced climatic change and changes caused by other external and internal factors. The present project addresses all of these questions. Many of the diverse facets of greenhouse-gas-related climate research can be grouped under three interlinked subject areas: modeling, first detection and supporting data. This project will include the analysis of climate forcing factors, the development and refinement of transient response climate models, and the use of instrumental data in validating General Circulation Models (GCMs)

  17. Flow induced vibrations in gas tube assembly of centrifuge

    International Nuclear Information System (INIS)

    Alam, M.; Atta, M.A.; Mirza, J.A.; Khan, A.Q.

    1986-01-01

    A centrifuge essentially consists of a rotor rotating at very high speed. Gas tube assembly, located at the center of the rotor, is used to introduce feed gas into the rotor and remove product and waste streams from it. The gas tube assembly is thus a static component, the product and waste scoops of which are lying in the high pressure region of a fluid rotating at very high speed. This can cause flow induced vibrations in the gas tube assembly. Such vibrations affect not only the mechanical stability of the gas tube assembly but may also reduce the separative power of the centrifuge. In a cascade, if some of the centrifuges have gas tube vibration, then cascade performance will be affected. A theoretical analysis of the effect of waste tube vibrations on product and waste flow rates and pressures in the centrifuge is presented. A simple stage consisting of two centrifuges, in which one has tube vibration, is considered for this purpose. The results are compared with experiment. It is shown that waste tube vibration generates oscillations in waste and product flow rates that are observable outside the centrifuge. (author)

  18. Shale Gas Exploration and Exploitation Induced Risks - SHEER

    Science.gov (United States)

    Capuano, Paolo; Orlecka-Sikora, Beata; Lasocki, Stanislaw; Cesca, Simone; Gunning, Andrew; jaroslawsky, Janusz; Garcia-Aristizabal, Alexander; Westwood, Rachel; Gasparini, Paolo

    2017-04-01

    Shale gas operations may affect the quality of air, water and landscapes; furthermore, it can induce seismic activity, with the possible impacts on the surrounding infrastructure. The SHEER project aims at setting up a probabilistic methodology to assess and mitigate the short and the long term environmental risks connected to the exploration and exploitation of shale gas. In particular we are investigating risks associated with groundwater contamination, air pollution and induced seismicity. A shale gas test site located in Poland (Wysin) has been monitored before, during and after the fracking operations with the aim of assessing environmental risks connected with groundwater contamination, air pollution and earthquakes induced by fracking and injection of waste water. The severity of each of these hazards depends strongly on the unexpected enhanced permeability pattern, which may develop as an unwanted by-product of the fracking processes and may become pathway for gas and fluid migration towards underground water reservoirs or the surface. The project is devoted to monitor and understand how far this enhanced permeability pattern develops both in space and time. The considered hazards may be at least partially inter-related as they all depend on this enhanced permeability pattern. Therefore they are being approached from a multi-hazard, multi parameter perspective. We expect to develop methodologies and procedures to track and model fracture evolution around shale gas exploitation sites and a robust statistically based, multi-parameter methodology to assess environmental impacts and risks across the operational lifecycle of shale gas. The developed methodologies are going to be applied and tested on a comprehensive database consisting of seismicity, changes of the quality of ground-waters and air, ground deformations, and operational data collected from the ongoing monitoring episode (Wysin) and past episodes: Lubocino (Poland), Preese Hall (UK), Oklahoma (USA

  19. Terahertz gas sensor based on absorption-induced transparency

    Directory of Open Access Journals (Sweden)

    Rodrigo Sergio G.

    2016-01-01

    Full Text Available A system for the detection of spectral signatures of gases at the Terahertz regime is presented. The system consists in an initially opaque holey metal film whereby the introduction of a gas provokes the appearance of spectral features in transmission and reflection, due to the phenomenom of absorption-induced transparency (AIT. The peaks in transmission and dips in reflection observed in AIT occur close to the absorption energies of the molecules, hence its name. The presence of the gas would be thus revealed as a strong drop in reflectivity measurements at one (or several of the gas absorption resonances. As a proof of principle, we theoretically demonstrate how the AIT-based sensor would serve to detect tiny amounts of hydrocyanic acid.

  20. Heavy-Ion-Induced Electronic Desorption of Gas from Metals

    CERN Document Server

    Molvik, A W; Mahner, E; Kireeff Covo, M; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Krämer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2007-01-01

    During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dEe/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  1. Buffer mass test - Buffer materials

    International Nuclear Information System (INIS)

    Pusch, R.; Boergesson, L.

    1982-08-01

    Commercial Na bentonite (MX-80) is the clay component of the buffer material in the heater holes as well of the tunnel backfill. Important characteristics are the clay content, liquid limit, X-ray diffraction pattern, water content, and degree of granulation. The ballast material consists of quartz-rich sand and feldspar-rich filler. The preparation of highly compacted bentonite for the near-field isolation of the canister was made by using isostatic compaction technique. The resulting dense bentonite core was cut into regularly shaped blocks which were arranged around each heater and lowered as one unit - heavily instrumented - in the respective deposition holes. For three of the six holes a narrow slot was left open between the bentonite stack and the rock; for the remaining ones a wider slot was chosen with a fill of soft bentonite powder. Both arrangements are expected to yield an ultimate bulk density which is sufficiently high to fulfil the requirement of a negligible permeability and a sufficient swelling pressure as well as heat conductivity, which are the essential parameters. The tunnel backfill, which consists of a mixture of suitably graded ballast material and MX-80 powder, has a considerably lower swelling pressure and heat conductivity, and a higher permeability, all these parameters still within the requirements of the KBS 2 concept. The various zones with different bentonite/sand ratios and the technique to apply them are described in the final part of the report. (Author)

  2. Research on Greenhouse-Gas-Induced Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, M. E.

    2001-07-15

    During the 5 years of NSF grant ATM 95-22681 (Research on Greenhouse-Gas-Induced Climate Change, $1,605,000, 9/15/1995 to 8/31/2000) we have performed work which we are described in this report under three topics: (1) Development and Application of Atmosphere, Ocean, Photochemical-Transport, and Coupled Models; (2) Analysis Methods and Estimation; and (3) Climate-Change Scenarios, Impacts and Policy.

  3. Substrate-induced instability in gas microstrip detectors

    International Nuclear Information System (INIS)

    Bateman, J.E.; Connolly, J.F.

    1992-12-01

    The results of a programme of research into substrate-induced gain instability in gas microstrip detectors are reported. Information has been collected on a wide range of substrates including many commonly available glasses and ceramics. A theoretical model of the gain instability is proposed. While we have not yet found an acceptable substrate for the construction of high flux detectors our experience points to electronically conductive glasses as the most promising source of a stable substrate. (Author)

  4. Earthquake induced rock shear through a deposition hole when creep is considered - first model. Effect on the canister and the buffer

    Energy Technology Data Exchange (ETDEWEB)

    Hernelind, Jan [5T Engineering AB, Vaesteraas (Sweden)

    2006-08-15

    March, 2000, a study regarding 'Earthquake induced rock shear through a deposition hole' was performed. Existing fractures crossing a deposition hole may be activated and sheared by an earthquake. The effect of such a rock shear has been investigated in a project that includes both laboratory tests and finite element calculations. The buffer material in a deposition hole acts as a cushion between the canister and the rock, which reduces the effect of a rock shear substantially. Lower density of the buffer yields softer material and reduced effect on the canister. However, at the high density that is suggested for a repository the stiffness of the buffer is rather high. The stiffness is also a function of the rate of shear, which means that there may be a substantial damage on the canister at very high shear rates. The rock shear has been modeled with finite element calculations with the code ABAQUS. A three-dimensional finite element mesh of the buffer and the canister has been created and simulation of a rock shear has been performed. The rock shear has been assumed to take place perpendicular to the canister at the quarter point. The shear calculations have been driven to a total shear of 20 cm. This report summarizes the effect of considering creep in the canister for one of the previous cases. Two different creep models have been used - the first one has been suggested by K Pettersson and the second one has been suggested by R Sandstroem. Both have been implemented in the FE-code ABAQUS as a user supplied subroutine CREEP. This report summarizes results obtained by using the first model suggested by K Pettersson. As can be seen from the obtained results using the first creep model (in the following named creep{sub k}p) the effect of creep in copper doesn't affect stresses and strains in the buffer and the steel part very much. However, especially the stresses in the canister are highly affected.

  5. Boosting recovery rather than buffering reactivity: Higher stress-induced oxytocin secretion is associated with increased cortisol reactivity and faster vagal recovery after acute psychosocial stress.

    Science.gov (United States)

    Engert, Veronika; Koester, Anna M; Riepenhausen, Antje; Singer, Tania

    2016-12-01

    Animal models and human studies using paradigms designed to stimulate endogenous oxytocin release suggest a stress-buffering role of oxytocin. We here examined the involvement of stress-induced peripheral oxytocin secretion in reactivity and recovery phases of the human psychosocial stress response. Healthy male and female participants (N=114) were subjected to a standardized laboratory stressor, the Trier Social Stress Test. In addition to plasma oxytocin, cortisol was assessed as a marker of hypothalamic-pituitary-adrenal (HPA-) axis activity, alpha-amylase and heart rate as markers of sympathetic activity, high frequency heart rate variability as a marker of vagal tone and self-rated anxiety as an indicator of subjective stress experience. On average, oxytocin levels increased by 51% following psychosocial stress. The stress-induced oxytocin secretion, however, did not reduce stress reactivity. To the contrary, higher oxytocin secretion was associated with greater cortisol reactivity and peak cortisol levels in both sexes. In the second phase of the stress response the opposite pattern was observed, with higher oxytocin secretion associated with faster vagal recovery. We suggest that after an early stage of oxytocin and HPA-axis co-activation, the stress-reducing action of oxytocin unfolds. Due to the time lag it manifests as a recovery-boosting rather than a reactivity-buffering effect. By reinforcing parasympathetic autonomic activity, specifically during stress recovery, oxytocin may provide an important protective function against the health-compromising effects of sustained stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Earthquake induced rock shear through a deposition hole. Influence of shear plane inclination and location as well as buffer properties on the damage caused to the canister

    Energy Technology Data Exchange (ETDEWEB)

    Boergesson, Lennart [Clay Technology AB, Lund (Sweden); Hernelind, Jan [5T Engineering AB, Vaesteraas (Sweden)

    2006-10-15

    The effect on the canister of an earthquake induced 20 cm rock shear with the shear rate 1 m/s along a fracture intersecting a deposition hole in a KBS-V repository has been investigated for a number of different shear cases and for different properties of the buffer material. The scenarios have been modelled with the finite element method and calculations have been done using the code ABAQUS. D-element models of the rock, the buffer and the canister have been used. Contact elements that can model separation have been used for the interfaces between the buffer and the rock and the interfaces between the buffer and the canister. The influence of mainly the following factors has been investigated: 1. Inclination of the intersecting fracture. 2. Shear direction when the fracture is not horizontal (inclination deviates from 90 deg). 3. Location of the shear plane when the inclination is 90 deg. 4. Magnitude of the shear displacement. 5. Bentonite type. 6. Bentonite density. 7. Transformation of the buffer to illite or cemented bentonite. The results from the calculations show that all these factors have important influence on the damage of the canister but the influence is for most factors not easily described since there are mutual interferences between the different factors. Plastic strain larger than 1% was reached in the copper already at 10 cm shear in all cases with Na- and Ca- bentonite. However, for several cases of Na-bentonite and one case of Ca-bentonite such plastic strain was only reached in the lid. The plastic strain in the steel was generally smaller than in the copper mainly due to the higher yield stress in the steel. For all cases of Na-bentonite except one and for about half of the Ca-bentonite cases the plastic strain in the steel was smaller than 1% after 10 cm shear. The shear inclination 45 deg was more harmful for the copper tube than the shear inclination 90 deg when tension shear was considered. At the shear inclinations 45 deg and 22.5 deg

  7. Earthquake induced rock shear through a deposition hole. Influence of shear plane inclination and location as well as buffer properties on the damage caused to the canister

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Hernelind, Jan

    2006-10-01

    The effect on the canister of an earthquake induced 20 cm rock shear with the shear rate 1 m/s along a fracture intersecting a deposition hole in a KBS-V repository has been investigated for a number of different shear cases and for different properties of the buffer material. The scenarios have been modelled with the finite element method and calculations have been done using the code ABAQUS. D-element models of the rock, the buffer and the canister have been used. Contact elements that can model separation have been used for the interfaces between the buffer and the rock and the interfaces between the buffer and the canister. The influence of mainly the following factors has been investigated: 1. Inclination of the intersecting fracture. 2. Shear direction when the fracture is not horizontal (inclination deviates from 90 deg). 3. Location of the shear plane when the inclination is 90 deg. 4. Magnitude of the shear displacement. 5. Bentonite type. 6. Bentonite density. 7. Transformation of the buffer to illite or cemented bentonite. The results from the calculations show that all these factors have important influence on the damage of the canister but the influence is for most factors not easily described since there are mutual interferences between the different factors. Plastic strain larger than 1% was reached in the copper already at 10 cm shear in all cases with Na- and Ca- bentonite. However, for several cases of Na-bentonite and one case of Ca-bentonite such plastic strain was only reached in the lid. The plastic strain in the steel was generally smaller than in the copper mainly due to the higher yield stress in the steel. For all cases of Na-bentonite except one and for about half of the Ca-bentonite cases the plastic strain in the steel was smaller than 1% after 10 cm shear. The shear inclination 45 deg was more harmful for the copper tube than the shear inclination 90 deg when tension shear was considered. At the shear inclinations 45 deg and 22.5 deg

  8. Creep in buffer clay

    International Nuclear Information System (INIS)

    Pusch, R.; Adey, R.

    1999-12-01

    The study involved characterization of the microstructural arrangement and molecular forcefields in the buffer clay for getting a basis for selecting suitable creep models. It is concluded that the number of particles and wide range of the particle bond spectrum require that stochastical mechanics and thermodynamics will be considered and they are basic to the creep model proposed for predicting creep settlement of the canisters. The influence of the stress level on creep strain of MX-80 clay is not well known but for the buffer creep is approximately proportional to stress. Theoretical considerations suggest a moderate impact for temperatures up to 90 deg C and this is supported by model experiments. It is believed that the assumption of strain being proportional to temperature is conservative. The general performance of the stochastic model can be illustrated in principle by use of visco-elastic rheological models implying a time-related increase in viscosity. The shear-induced creep settlement under constant volume conditions calculated by using the proposed creep model is on the order of 1 mm in ten thousand years and up to a couple of millimeters in one million years. It is much smaller than the consolidation settlement, which is believed to be on the order of 10 mm. The general conclusion is that creep settlement of the canisters is very small and of no significance to the integrity of the buffer itself or of the canisters

  9. Flow-induced and acoustically induced vibration experience in operating gas-cooled reactors

    International Nuclear Information System (INIS)

    Halvers, L.J.

    1977-03-01

    An overview has been presented of flow-induced and acoustically induced vibration failures that occurred in the past in gas-cooled graphite-moderated reactors, and the importance of this experience for the Gas-Cooled Fast-Breeder Reactor (GCFR) project has been assessed. Until now only failures in CO 2 -cooled reactors have been found. No problems with helium-cooled reactors have been encountered so far. It is shown that most of the failures occurred because flow-induced and acoustically induced dynamic loads were underestimated, while at the same time not enough was known about the influence of environmental parameters on material behavior. All problems encountered were solved. The comparison of the influence of the gas properties on acoustically induced and flow-induced vibration phenomena shows that the interaction between reactor design and the thermodynamic properties of the primary coolant precludes a general preference for either carbon dioxide or helium. The acoustic characteristics of CO 2 and He systems are different, but the difference in dynamic loadings due to the use of one rather than the other remains difficult to predict. A slight preference for helium seems, however, to be justified

  10. Differential effects of buffer pH on Ca2+-induced ROS emission with inhibited mitochondrial complex I and III

    Directory of Open Access Journals (Sweden)

    Daniel P Lindsay

    2015-03-01

    Full Text Available Excessive mitochondrial reactive oxygen species (ROS emission is a critical component in the etiolo-gy of ischemic injury. Complex I and complex III of the electron transport chain are considered the primary sources of ROS emission during cardiac ischemia and reperfusion (IR injury. Several factors modulate ischemic ROS emission, such as an increase in extra-matrix Ca2+, a decrease in extra-matrix pH, and a change in substrate utilization. Here we examined the combined effects of these factors on ROS emission from respiratory complex I and III under conditions of simulated IR injury. Guinea pig heart mitochondria were suspended in experimental buffer at a given pH and incubated with or without CaCl2. Mitochondria were then treated with either pyruvate, a complex I substrate, followed by rote-none, a complex I inhibitor, or succinate, a complex II substrate, followed by antimycin A, a complex III inhibitor. H2O2 release rate and matrix volume were compared with and without adding CaCl2 and at pH 7.15, 6.9, or 6.5 with pyruvate + rotenone or succinate + antimycin A to simulate conditions that may occur during in vivo cardiac IR injury. We found a large increase in H2O2 release with high [CaCl2] and pyruvate + rotenone at pH 6.9, but not at pHs 7.15 or 6.5. Large increases in H2O2 release rate also occurred at each pH with high [CaCl2] and succinate + antimycin A, with the highest levels observed at pH 7.15. The increases in H2O2 release were associated with significant mitochondrial swelling, and both H2O2 release and swelling were abolished by cyclosporine A, a desensitizer of the mitochondrial permeability transition pore. These results indicate that ROS production by complex I and by III is differently affected by buffer pH and Ca2+ loading with mPTP opening. The study sug-gests that changes in the levels of cytosolic Ca2+ and pH during IR alter the relative amounts of ROS produced at mitochondrial respiratory complex I and complex III.

  11. Spectroscopic analysis of femtosecond laser-induced gas breakdown

    International Nuclear Information System (INIS)

    Hermann, J.; Bruneau, S.; Sentis, M.

    2004-01-01

    The plasma generated by the interaction of a femtosecond laser pulse with gas has been analyzed using time- and space-resolved emission spectroscopy. The laser beam has been focused with a microscope objective into different gases (air, Ar, He) at pressures ranging from 10 2 to 10 5 Pa. From the analysis of spectral line emission from ions and neutral atoms, the plasma parameters and the plasma composition have been determined as a function of time and space. Furthermore, the generation of fast electrons and/or VUV radiation by the femtosecond laser interaction with the gas was brought to the fore. From the time- and space-evolution of the plasma parameters, a rough estimation of initial values of electron density and refraction index in the focal volume has been performed. These results are compared to analysis of the laser beam transmitted by the plasma. The latter show that only a small fraction of the laser energy is absorbed by the plasma while the spatial distribution of the transmitted laser beam is strongly perturbed by the plasma, which acts like a defocusing lens. However, in ambient helium, the plasma defocusing is weak due to the high ionization potential of helium. The understanding of femtosecond laser-induced gas breakdown is useful for process optimization in femtosecond laser applications like micromachining or surface microanalysis, etc

  12. Two-photon induced fluorescence of Cy5-DNA in buffer solution and on silver island films

    International Nuclear Information System (INIS)

    Lukomska, Joanna; Gryczynski, Ignacy; Malicka, Joanna; Makowiec, Slawomir; Lakowicz, Joseph R.; Gryczynski, Zygmunt

    2005-01-01

    We report the observation of a strong two-photon induced fluorescence emission of Cy5-DNA within the tunable range of a Ti:Sapphire laser. The estimated two-photon cross-section for Cy5-DNA of 400 GM is about 3.5-fold higher than it was reported for rhodamine B. The fundamental anisotropies of Cy5-DNA are close to the theoretical limits of 2/5 and 4/7 for one- and two-photon excitation, respectively. We also observed an enhanced two-photon induced fluorescence (TPIF) of Cy5-DNA deposited on silver island films (SIFs). In the presence of SIFs, the TPIF is about 100-fold brighter. The brightness increase of Cy5-DNA TPIF near SIFs is mostly due to enhanced local field

  13. Buffer Zone Fact Sheets

    Science.gov (United States)

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

  14. Collision-induced polarizabilities of inert gas atoms

    International Nuclear Information System (INIS)

    Clarke, K.L.; Madden, P.A.; Buckingham, A.D.

    1978-01-01

    The use of polarizability densities to calculate collision-induced polarizabilities is investigated. One method for computing polarizabilities of inert gas diatoms employs atomic polarizability densities from finite-field Hartree-Fock calculations, together with classical equations for the polarization of dielectrics. It is shown that this model gives inaccurate values for both the local fields and the local response to non-uniform fields. An alternative method incorporating the same physical effects is used to compute the pair polarizabilities to first order in the interatomic interaction. To first order the pair contribution to the trace of the polarizability is negative at short range. The calculated anisotropy does not differ significantly from the DID value, whereas the polarizability density calculation gives a substantial reduction in the anisotropy. (author)

  15. Buffer capacity of the coelomic fluid in echinoderms.

    Science.gov (United States)

    Collard, Marie; Laitat, Kim; Moulin, Laure; Catarino, Ana I; Grosjean, Philippe; Dubois, Philippe

    2013-09-01

    The increase in atmospheric CO2 due to anthropogenic activity results in an acidification of the surface waters of the oceans. The impact of these chemical changes depends on the considered organisms. In particular, it depends on the ability of the organism to control the pH of its inner fluids. Among echinoderms, this ability seems to differ significantly according to species or taxa. In the present paper, we investigated the buffer capacity of the coelomic fluid in different echinoderm taxa as well as factors modifying this capacity. Euechinoidea (sea urchins except Cidaroidea) present a very high buffer capacity of the coelomic fluid (from 0.8 to 1.8mmolkg(-1) SW above that of seawater), while Cidaroidea (other sea urchins), starfish and holothurians have a significantly lower one (from -0.1 to 0.4mmolkg(-1) SW compared to seawater). We hypothesize that this is linked to the more efficient gas exchange structures present in the three last taxa, whereas Euechinoidea evolved specific buffer systems to compensate lower gas exchange abilities. The constituents of the buffer capacity and the factors influencing it were investigated in the sea urchin Paracentrotus lividus and the starfish Asterias rubens. Buffer capacity is primarily due to the bicarbonate buffer system of seawater (representing about 63% for sea urchins and 92% for starfish). It is also partly due to coelomocytes present in the coelomic fluid (around 8% for both) and, in P. lividus only, a compound of an apparent size larger than 3kDa is involved (about 15%). Feeding increased the buffer capacity in P. lividus (to a difference with seawater of about 2.3mmolkg(-1) SW compared to unfed ones who showed a difference of about 0.5mmolkg(-1) SW) but not in A. rubens (difference with seawater of about 0.2 for both conditions). In P. lividus, decreased seawater pH induced an increase of the buffer capacity of individuals maintained at pH7.7 to about twice that of the control individuals and, for those at pH7

  16. Kinetics of an acid-base catalyzed reaction (aspartame degradation) as affected by polyol-induced changes in buffer pH and pK values.

    Science.gov (United States)

    Chuy, S; Bell, L N

    2009-01-01

    The kinetics of an acid-base catalyzed reaction, aspartame degradation, were examined as affected by the changes in pH and pK(a) values caused by adding polyols (sucrose, glycerol) to phosphate buffer. Sucrose-containing phosphate buffer solutions had a lower pH than that of phosphate buffer alone, which contributed, in part, to reduced aspartame reactivity. A kinetic model was introduced for aspartame degradation that encompassed pH and buffer salt concentrations, both of which change with a shift in the apparent pK(a) value. Aspartame degradation rate constants in sucrose-containing solutions were successfully predicted using this model when corrections (that is, lower pH, lower apparent pK(a) value, buffer dilution from the polyol) were applied. The change in buffer properties (pH, pK(a)) from adding sucrose to phosphate buffer does impact food chemical stability. These effects can be successfully incorporated into predictive kinetic models. Therefore, pH and pK(a) changes from adding polyols to buffer should be considered during food product development.

  17. Safety requirements for buildings under induced earthquakes due to gas extraction

    NARCIS (Netherlands)

    Steenbergen, R.D.J.M.; Vrouwenvelder, A.C.W.M.

    2017-01-01

    In the Dutch province of Groningen over the last year shallow earthquakes are induced due to large scale gas extraction from the gas field at 3 km depth. The induced earthquakes differ from the better known tectonic earthquakes all over the world, caused by movement of the earth at large depths. The

  18. Redox Buffer Strength

    Science.gov (United States)

    de Levie, Robert

    1999-04-01

    The proper functioning of enzymes in bodily fluids requires that the pH be maintained within rather narrow limits. The first line of defense against large pH fluctuations in such fluids is the passive control provided by the presence of pH buffers. The ability of pH buffers to stabilize the pH is indicated by the buffer value b introduced in 1922 by van Slyke. It is equally important for many enzymes that the redox potential is kept within a narrow range. In that case, stability of the potential is most readily achieved with a redox buffer. In this communication we define the redox buffer strength by analogy with acid-base buffer strength.

  19. Fluid-induced vibration of composite natural gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Zou, G.P.; Cheraghi, N.; Taheri, F. [Dalhousie Univ., Dept. of Civil Engineering, Halifax, NS (Canada)

    2005-02-01

    Advancements in materials bonding techniques have led to the use of reinforced composite pipelines. The use of steel pipe with a fiber-reinforced composite over-wrap together has produced an exceptionally strong pipe with positive advantages in weight and corrosion resistivity. Understanding the dynamic characteristics of this kind of sub-sea composite pipelines, which often accommodate axial flow of gas, and prediction of their response is of great interest. This paper presents a state-variable model developed for the analysis of fluid-induced vibration of composite pipeline systems. Simply supported, clamped and clamped-simply supported pipelines are investigated. The influence of fluid's Poisson ratio, the ratio of pipe radius to pipe-wall thickness, laminate layup, the ratio of liquid mass density to pipe-wall mass density, the fluid velocity, initial tension and fluid pressure are all considered. The results of our proposed methodology are compared with those of finite element analysis, using ANSYS ssoftware. (Author)

  20. Organellar Calcium Buffers

    Science.gov (United States)

    Prins, Daniel; Michalak, Marek

    2011-01-01

    Ca2+ is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca2+ storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca2+ is buffered by specific proteins known as Ca2+ buffers. Ca2+ buffers are a diverse group of proteins, varying in their affinities and capacities for Ca2+, but they typically also carry out other functions within the cell. The wide range of organelles containing Ca2+ and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca2+ signaling, mediated by a variety of organellar Ca2+ buffers. PMID:21421925

  1. A current induced diffusion model of gas sputtering

    International Nuclear Information System (INIS)

    Hotston, E.S.

    1980-01-01

    A model is proposed to explain the experimental results on deuteron trapping in stainless steel targets at low temperatures carried out at Garching and Culham. The model proposes that the ions are trapped in two kinds of sites: Deep sites with high activation energy and shallow sites of low activation energy. Trapped deuterons reach the surface of the target by being expelled from shallow sites by the action of the ion beam and migrate to nearby sites in a random way, thus moving by a bombardment induced diffusion. Ions diffusing to the target surface and being released are said to be sputtered from the target. It has been necessary to assume numerical values for sizes of some of the processes which occur. With a suitable choice of values the model successfully predicts the numbers of deuterons trapped per unit area of the target, the obserbed density profile of the trapped ions and the threshold at which sputtering starts. The model also successfully describes the replacement of the trapped deuterons by protons, when the deuteron beam is replaced by a proton beam. The collision cross-section for beam ions and ions trapped in shallow sites is too large, 4 x 10 -13 cm 2 , for a binary collision and it is tentatively suggested that the ions in the shallow sites may be in small voids in the target which may be connected with blister formation. Comparison of the present model with one being developed to describe the trapping of deuterons in carbon suggests that it may be possible to describe all gas sputtering experiments in terms of diffusion processes. (orig.)

  2. Principle and Performance of Gas Self-inducing Reactors and Applications to Biotechnology.

    Science.gov (United States)

    Ye, Qin; Li, Zhimin; Wu, Hui

    2016-01-01

    Gas-liquid contacting is an important unit operation in chemical and biochemical processes, but the gas utilization efficiency is low in conventional gas-liquid contactors especially for sparingly soluble gases. The gas self-inducing impeller is able to recycle gas in the headspace of a reactor to the liquid without utilization of additional equipment such as a gas compressor, and thus, the gas utilization efficiency is significantly enhanced. Gas induction is caused by the low pressure or deep vortex at a sufficiently high impeller speed, and the speed at which gas induction starts is termed the critical speed. The critical impeller speed, gas-induction flow rate, power consumption, and gas-liquid mass transfer are determined by the impeller design and operation conditions. When the reactor is operated in a dead-end mode, all the introduced gas can be completely used, and this feature is especially favorable to flammable and/or toxic gases. In this article, the principles, designs, characteristics of self-inducing reactors, and applications to biotechnology are described.

  3. Models of Tidally Induced Gas Filaments in the Magellanic Stream

    Science.gov (United States)

    Pardy, Stephen A.; D’Onghia, Elena; Fox, Andrew J.

    2018-04-01

    The Magellanic Stream and Leading Arm of H I that stretches from the Large and Small Magellanic Clouds (LMC and SMC) and over 200° of the Southern sky is thought to be formed from multiple encounters between the LMC and SMC. In this scenario, most of the gas in the Stream and Leading Arm is stripped from the SMC, yet recent observations have shown a bifurcation of the Trailing Arm that reveals LMC origins for some of the gas. Absorption measurements in the Stream also reveal an order of magnitude more gas than in current tidal models. We present hydrodynamical simulations of the multiple encounters between the LMC and SMC at their first pass around the Milky Way, assuming that the Clouds were more extended and gas-rich in the past. Our models create filamentary structures of gas in the Trailing Stream from both the LMC and SMC. While the SMC trailing filament matches the observed Stream location, the LMC filament is offset. In addition, the total observed mass of the Stream in these models is underestimated by a factor of four when the ionized component is accounted for. Our results suggest that there should also be gas stripped from both the LMC and SMC in the Leading Arm, mirroring the bifurcation in the Trailing Stream. This prediction is consistent with recent measurements of spatial variation in chemical abundances in the Leading Arm, which show that gas from multiple sources is present, although its nature is still uncertain.

  4. Modeling of fault reactivation and induced seismicity during hydraulic fracturing of shale-gas reservoirs

    Science.gov (United States)

    We have conducted numerical simulation studies to assess the potential for injection-induced fault reactivation and notable seismic events associated with shale-gas hydraulic fracturing operations. The modeling is generally tuned toward conditions usually encountered in the Marce...

  5. Reversible brain inactivation induces discontinuous gas exchange in cockroaches.

    Science.gov (United States)

    Matthews, Philip G D; White, Craig R

    2013-06-01

    Many insects at rest breathe discontinuously, alternating between brief bouts of gas exchange and extended periods of breath-holding. The association between discontinuous gas exchange cycles (DGCs) and inactivity has long been recognised, leading to speculation that DGCs lie at one end of a continuum of gas exchange patterns, from continuous to discontinuous, linked to metabolic rate (MR). However, the neural hypothesis posits that it is the downregulation of brain activity and a change in the neural control of gas exchange, rather than low MR per se, which is responsible for the emergence of DGCs during inactivity. To test this, Nauphoeta cinerea cockroaches had their brains inactivated by applying a Peltier-chilled cold probe to the head. Once brain temperature fell to 8°C, cockroaches switched from a continuous to a discontinuous breathing pattern. Re-warming the brain abolished the DGC and re-established a continuous breathing pattern. Chilling the brain did not significantly reduce the cockroaches' MR and there was no association between the gas exchange pattern displayed by the insect and its MR. This demonstrates that DGCs can arise due to a decrease in brain activity and a change in the underlying regulation of gas exchange, and are not necessarily a simple consequence of low respiratory demand.

  6. Oxidation state specific generation of arsines from methylated arsenicals based on L-cysteine treatment in buffered media for speciation analysis by hydride generation-automated cryotrapping-gas chromatography-atomic absorption spectrometry with the multiatomizer

    Energy Technology Data Exchange (ETDEWEB)

    Matousek, Tomas [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 14220 Prague (Czech Republic)], E-mail: matousek@biomed.cas.cz; Hernandez-Zavala, Araceli [Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7310 (United States); Svoboda, Milan; Langrova, Lenka [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 14220 Prague (Czech Republic); Charles University, Faculty of Science, Albertov 8, 12840 Prague 2 (Czech Republic); Adair, Blakely M. [Pharmacokinetics Branch, Experimental Toxicology Division, National Health and Environmental Effects Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Drobna, Zuzana [Department of Nutrition, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Thomas, David J. [Pharmacokinetics Branch, Experimental Toxicology Division, National Health and Environmental Effects Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Styblo, Miroslav [Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7310 (United States); Department of Nutrition, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Dedina, Jiri [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 14220 Prague (Czech Republic)

    2008-03-15

    An automated system for hydride generation-cryotrapping-gas chromatography-atomic absorption spectrometry with the multiatomizer is described. Arsines are preconcentrated and separated in a Chromosorb filled U-tube. An automated cryotrapping unit, employing nitrogen gas formed upon heating in the detection phase for the displacement of the cooling liquid nitrogen, has been developed. The conditions for separation of arsines in a Chromosorb filled U-tube have been optimized. A complete separation of signals from arsine, methylarsine, dimethylarsine, and trimethylarsine has been achieved within a 60 s reading window. The limits of detection for methylated arsenicals tested were 4 ng l{sup -1}. Selective hydride generation is applied for the oxidation state specific speciation analysis of inorganic and methylated arsenicals. The arsines are generated either exclusively from trivalent or from both tri- and pentavalent inorganic and methylated arsenicals depending on the presence of L-cysteine as a prereductant and/or reaction modifier. A TRIS buffer reaction medium is proposed to overcome narrow optimum concentration range observed for the L-cysteine modified reaction in HCl medium. The system provides uniform peak area sensitivity for all As species. Consequently, the calibration with a single form of As is possible. This method permits a high-throughput speciation analysis of metabolites of inorganic arsenic in relatively complex biological matrices such as cell culture systems without sample pretreatment, thus preserving the distribution of tri- and pentavalent species.

  7. Effects of gas conditions on ASH induced agglomeration

    DEFF Research Database (Denmark)

    Ma, T.; Fan, C. G.; Hao, L. F.

    2016-01-01

    Agglomeration is a serious problem for gasification and combustion of biomass in fluidized bed. Agglomeration characteristics may be affected by gas condition, but the literature is quite vague in this regard. This study focuses on the effects of gasification and combustion condition...... on agglomeration tendency with two types of biomass ash, including rice straw and wheat straw ash. The agglomerates are analyzed by SEM-EDS for morphology and elemental composition. Defluidization temperature (Td) in those two types of gas conditions is quite different. Tdin gasification condition is much lower...

  8. Small molecule inhibitors block Gas6-inducible TAM activation and tumorigenicity.

    Science.gov (United States)

    Kimani, Stanley G; Kumar, Sushil; Bansal, Nitu; Singh, Kamalendra; Kholodovych, Vladyslav; Comollo, Thomas; Peng, Youyi; Kotenko, Sergei V; Sarafianos, Stefan G; Bertino, Joseph R; Welsh, William J; Birge, Raymond B

    2017-03-08

    TAM receptors (Tyro-3, Axl, and Mertk) are a family of three homologous type I receptor tyrosine kinases that are implicated in several human malignancies. Overexpression of TAMs and their major ligand Growth arrest-specific factor 6 (Gas6) is associated with more aggressive staging of cancers, poorer predicted patient survival, acquired drug resistance and metastasis. Here we describe small molecule inhibitors (RU-301 and RU-302) that target the extracellular domain of Axl at the interface of the Ig-1 ectodomain of Axl and the Lg-1 of Gas6. These inhibitors effectively block Gas6-inducible Axl receptor activation with low micromolar IC 50s in cell-based reporter assays, inhibit Gas6-inducible motility in Axl-expressing cell lines, and suppress H1299 lung cancer tumor growth in a mouse xenograft NOD-SCIDγ model. Furthermore, using homology models and biochemical verifications, we show that RU301 and 302 also inhibit Gas6 inducible activation of Mertk and Tyro3 suggesting they can act as pan-TAM inhibitors that block the interface between the TAM Ig1 ectodomain and the Gas6 Lg domain. Together, these observations establish that small molecules that bind to the interface between TAM Ig1 domain and Gas6 Lg1 domain can inhibit TAM activation, and support the further development of small molecule Gas6-TAM interaction inhibitors as a novel class of cancer therapeutics.

  9. Ultrasound-induced Gas Release from Contrast Agent Microbubbles

    NARCIS (Netherlands)

    Postema, M.A.B.; Postema, Michiel; Bouakaz, Ayache; Versluis, Michel; de Jong, N.

    2005-01-01

    We investigated gas release from two hard-shelled ultrasound contrast agents by subjecting them to high-mechanical index (MI) ultrasound and simultaneously capturing high-speed photographs. At an insonifying frequency of 1.7 MHz, a larger percentage of contrast bubbles is seen to crack than at 0.5

  10. Direct monitoring of wind-induced pressure-pumping on gas transport in soil

    Science.gov (United States)

    Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

    2017-04-01

    Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non

  11. Buffer design 2012

    International Nuclear Information System (INIS)

    Juvankoski, M.

    2013-08-01

    Posiva's spent nuclear fuel disposal is based on the KBS-3V concept and on the characteristics of the Olkiluoto site. In this concept single canisters containing spent nuclear fuel surrounded by a bentonite buffer are emplaced in individual vertical boreholes drilled in the floor of deposition tunnels in bedrock at about 420 m depth below ground level. Disk type bentonite blocks are installed at the bottom of the hole and on the top of the disposal canister. Ring type bentonite blocks surround the canisters. This report describes the detailed design of the buffer for a KBS-3V repository. The report presents the design basis, the reference design, and summarises the performance analyses carried out for the design. This report addresses aspects concerning the manufacture, quality control, mechanical strength, chemical resistance, thermal dimensioning, handling of buffer components and material ageing phenomena including the effect of radiation. Interaction of buffer and other engineered barriers are included in the study. The long-term evolution of the repository and its effective drivers are considered if they have an impact on the buffer performance but operational safety aspects are also included because they may affect long-term safety. (orig.)

  12. Gas-induced friction and diffusion of rigid rotors

    Science.gov (United States)

    Martinetz, Lukas; Hornberger, Klaus; Stickler, Benjamin A.

    2018-05-01

    We derive the Boltzmann equation for the rotranslational dynamics of an arbitrary convex rigid body in a rarefied gas. It yields as a limiting case the Fokker-Planck equation accounting for friction, diffusion, and nonconservative drift forces and torques. We provide the rotranslational friction and diffusion tensors for specular and diffuse reflection off particles with spherical, cylindrical, and cuboidal shape, and show that the theory describes thermalization, photophoresis, and the inverse Magnus effect in the free molecular regime.

  13. The SVT Hit Buffer

    International Nuclear Information System (INIS)

    Belforte, S.; Dell'Orso, M.; Donati, S.

    1996-01-01

    The Hit Buffer is part of the Silicon Vertex Tracker, a trigger processor dedicated to the reconstruction of particle trajectories in the Silicon Vertex Detector and the Central Tracking Chamber of the Collider Detector at Fermilab. The Hit Buffer is a high speed data-traffic node, where thousands of words are received in arbitrary order and simultaneously organized in an internal structured data base, to be later promptly retrieved and delivered in response to specific requests. The Hit Buffer is capable of processing data at a rate of 25 MHz, thanks to the use of special fast devices like Cache-Tag RAMs and high performance Erasable Programmable Logic Devices from the XILINX XC7300 family

  14. A parallel buffer tree

    DEFF Research Database (Denmark)

    Sitchinava, Nodar; Zeh, Norbert

    2012-01-01

    We present the parallel buffer tree, a parallel external memory (PEM) data structure for batched search problems. This data structure is a non-trivial extension of Arge's sequential buffer tree to a private-cache multiprocessor environment and reduces the number of I/O operations by the number of...... in the optimal OhOf(psortN + K/PB) parallel I/O complexity, where K is the size of the output reported in the process and psortN is the parallel I/O complexity of sorting N elements using P processors....

  15. Attack-Induced Entanglement of Noninteracting Fermi Gas

    International Nuclear Information System (INIS)

    Ren Jie; Zhu Shiqun

    2008-01-01

    The bipartite entanglement in Fermi gas without interaction is investigated when there are three fermions in the system. The negativity and the von Neumann entropy are employed to measure the entanglement of the system. The position of the third fermion can affect the entanglement between the first and the second fermions. The entanglement can be enhanced or suppressed when the third fermion changes its position. When the two fermions are at the same position or when their distance is more than 2.0/k F , the third fermion cannot affect them

  16. Measurement of gas flow velocities by laser-induced gratings

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B; Stampanoni-Panariello, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Kozlov, A D.N. [General Physics Institute, Moscow (Russian Federation)

    1999-08-01

    Time resolved light scattering from laser-induced electrostrictive gratings was used for the determination of flow velocities in air at room temperature. By measuring the velocity profile across the width of a slit nozzle we demonstrated the high spatial resolution (about 200 mm) of this novel technique. (author) 3 figs., 1 ref.

  17. Buffer Zone Sign Template

    Science.gov (United States)

    The certified pesticide applicator is required to post a comparable sign, designating a buffer zone around the soil fumigant application block in order to control exposure risk. It must include the don't walk symbol, product name, and applicator contact.

  18. Buffer Zone, Nicosia

    OpenAIRE

    Sorensen, Marie Louise

    2010-01-01

    Images of the United Nations Buffer Zone or Green Line which has partitioned Cyprus since 1974 The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7/2007-2013] under grant agreement n° 217411.

  19. Gas6 induces cancer cell migration and epithelial–mesenchymal transition through upregulation of MAPK and Slug

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yunhee [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Lee, Mira [Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Semi, E-mail: semikim@kribb.re.kr [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of)

    2013-04-26

    Highlights: •We investigated the molecular mechanisms underlying Gas6-mediated cancer cell migration. •Gas6 treatment and subsequent Axl activation induce cell migration and EMT via upregulation of Slug. •Slug expression mediated by Gas6 is mainly through c-Jun and ATF-2 in an ERK1/2 and JNK-dependent manner. •The Gas6/Axl-Slug axis may be exploited as a target for anti-cancer metastasis therapy. -- Abstract: Binding of Gas6 to Axl (Gas6/Axl axis) alters cellular functions, including migration, invasion, proliferation, and survival. However, the molecular mechanisms underlying Gas6-mediated cell migration remain poorly understood. In this study, we found that Gas6 induced the activation of JNK and ERK1/2 signaling in cancer cells expressing Axl, resulting in the phosphorylation of activator protein-1 (AP-1) transcription factors c-Jun and ATF-2, and induction of Slug. Depletion of c-Jun or ATF-2 by siRNA attenuated the Gas6-induced expression of Slug. Slug expression was required for cell migration and E-cadherin reduction/vimentin induction induced by Gas6. These results suggest that Gas6 induced cell migration via Slug upregulation in JNK- and ERK1/2-dependent mechanisms. These data provide an important insight into the molecular mechanisms mediating Gas6-induced cell migration.

  20. Effect of Pressure-Induced Changes in the Ionization Equilibria of Buffers on Inactivation of Escherichia coli and Staphylococcus aureus by High Hydrostatic Pressure

    Science.gov (United States)

    Gayán, Elisa; Condón, Santiago; Álvarez, Ignacio; Nabakabaya, Maria

    2013-01-01

    Survival rates of Escherichia coli and Staphylococcus aureus after high-pressure treatment in buffers that had large or small reaction volumes (ΔV°), and which therefore underwent large or small changes in pH under pressure, were compared. At a low buffer concentration of 0.005 M, survival was, as expected, better in MOPS (morpholinepropanesulfonic acid), HEPES, and Tris, whose ΔV° values are approximately 5.0 to 7.0 cm3 mol−1, than in phosphate or dimethyl glutarate (DMG), whose ΔV° values are about −25 cm3 mol−1. However, at a concentration of 0.1 M, survival was unexpectedly better in phosphate and DMG than in MOPS, HEPES, or Tris. This was because the baroprotective effect of phosphate and DMG increased much more rapidly with increasing concentration than it did with MOPS, HEPES, or Tris. Further comparisons of survival in solutions of salts expected to cause large electrostriction effects (Na2SO4 and CaCl2) and those causing lower electrostriction (NaCl and KCl) were made. The salts with divalent ions were protective at much lower concentrations than salts with monovalent ions. Buffers and salts both protected against transient membrane disruption in E. coli, but the molar concentrations necessary for membrane protection were much lower for phosphate and Na2SO4 than for HEPES and NaCl. Possible protective mechanisms discussed include effects of electrolytes on water compressibility and kosmotropic and specific ion effects. The results of this systematic study will be of considerable practical significance in studies of pressure inactivation of microbes under defined conditions but also raise important fundamental questions regarding the mechanisms of baroprotection by ionic solutes. PMID:23624471

  1. The Water-Induced Linear Reduction Gas Diffusivity Model Extended to Three Pore Regions

    DEFF Research Database (Denmark)

    Chamindu, T. K. K. Deepagoda; de Jonge, Lis Wollesen; Kawamoto, Ken

    2015-01-01

    . Characterization of soil functional pore structure is an essential prerequisite to understand key gas transport processes in variably saturated soils in relation to soil ecosystems, climate, and environmental services. In this study, the water-induced linear reduction (WLR) soil gas diffusivity model originally...... gas diffusivity from moist to dry conditions across differently structured porous media, including narrow soil size fractions, perforated plastic blocks, fractured limestone, peaty soils, aggregated volcanic ash soils, and particulate substrates for Earth- or space-based applications. The new Cip...

  2. Sulforaphane induces phase II detoxication enzymes in mouse skin and prevents mutagenesis induced by a mustard gas analog

    Energy Technology Data Exchange (ETDEWEB)

    Abel, E.L. [Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957 (United States); Boulware, S. [Division of Pharmacy and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723 (United States); Fields, T.; McIvor, E.; Powell, K.L. [Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957 (United States); DiGiovanni, J.; Vasquez, K.M. [Division of Pharmacy and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723 (United States); MacLeod, M.C., E-mail: mcmacleod@mdanderson.org [Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957 (United States)

    2013-02-01

    Mustard gas, used in chemical warfare since 1917, is a mutagenic and carcinogenic agent that produces severe dermal lesions for which there are no effective therapeutics; it is currently seen as a potential terrorist threat to civilian populations. Sulforaphane, found in cruciferous vegetables, is known to induce enzymes that detoxify compounds such as the sulfur mustards that react through electrophilic intermediates. Here, we observe that a single topical treatment with sulforaphane induces mouse epidermal levels of the regulatory subunit of glutamate-cysteine ligase, the rate-limiting enzyme in glutathione biosynthesis, and also increases epidermal levels of reduced glutathione. Furthermore, a glutathione S-transferase, GSTA4, is also induced in mouse skin by sulforaphane. In an in vivo model in which mice are given a single mutagenic application of the sulfur mustard analog 2-(chloroethyl) ethyl sulfide (CEES), we now show that therapeutic treatment with sulforaphane abolishes the CEES-induced increase in mutation frequency in the skin, measured four days after exposure. Sulforaphane, a natural product currently in clinical trials, shows promise as an effective therapeutic against mustard gas. -- Highlights: ► Sulforaphane induces increased levels of glutathione in mouse skin. ► Sulforaphane induces increased levels of GSTA4 in mouse skin. ► Sulforaphane, applied after CEES-treatment, completely abolishes CEES-mutagenesis. ► The therapeutic effect may suggest a long biological half-life for CEES in vivo.

  3. Prospect of shale gas recovery enhancement by oxidation-induced rock burst

    Directory of Open Access Journals (Sweden)

    Lijun You

    2017-11-01

    Full Text Available By horizontal well multi-staged fracturing technology, shale rocks can be broken to form fracture networks via hydraulic force and increase the production rate of shale gas wells. Nonetheless, the fracturing stimulation effect may be offset by the water phase trapping damage caused by water retention. In this paper, a technique in transferring the negative factor of fracturing fluid retention into a positive factor of changing the gas existence state and facilitating shale cracking was discussed using the easy oxidation characteristics of organic matter, pyrite and other minerals in shale rocks. Furthermore, the prospect of this technique in tackling the challenges of large retention volume of hydraulic fracturing fluid in shale gas reservoirs, high reservoir damage risks, sharp production decline rate of gas wells and low gas recovery, was analyzed. The organic matter and pyrite in shale rocks can produce a large number of dissolved pores and seams to improve the gas deliverability of the matrix pore throats to the fracture systems. Meanwhile, in the oxidation process, released heat and increased pore pressure will make shale rock burst, inducing expansion and extension of shale micro-fractures, increasing the drainage area and shortening the gas flowing path in matrix, and ultimately, removing reservoir damage and improving gas recovery. To sum up, the technique discussed in the paper can be used to “break” shale rocks via hydraulic force and to “burst” shale rocks via chemical oxidation by adding oxidizing fluid to the hydraulic fracturing fluid. It can thus be concluded that this method can be a favorable supplementation for the conventional hydraulic fracturing of shale gas reservoirs. It has a broad application future in terms of reducing costs and increasing profits, maintaining plateau shale gas production and improving shale gas recovery.

  4. Role of buffer gases in optoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Thomas III, L.J.; Kelly, M.J.; Amer, N.M.

    1978-01-01

    The dependence of an acoustically resonant optoacoustic signal on the molecular weight and thermodynamic and transport properpties of the buffer gas is reported. Our results show that careful selection of such gases can significantly increase the sensitivity and flexibility of optoacoustic spectroscopy. We also demonstrate that such thermodynamic quantities as γ (equivalentC/sub p//C/sub v/) and sound velocity can now be measured readily and accurately. Other potential applications are suggested

  5. Laser-induced breakdown spectroscopy at a water/gas interface: A study of bath gas-dependent molecular species

    International Nuclear Information System (INIS)

    Adamson, M.; Padmanabhan, A.; Godfrey, G.J.; Rehse, S.J.

    2007-01-01

    Single-pulse laser-induced breakdown spectroscopy has been performed on the surface of a bulk water sample in an air, argon, and nitrogen gas environment to investigate emissions from hydrogen-containing molecules. A microplasma was formed at the gas/liquid interface by focusing a Nd:YAG laser beam operating at 1064 nm onto the surface of an ultra-pure water sample. A broadband Echelle spectrometer with a time-gated intensified charge-coupled device was used to analyze the plasma at various delay times (1.0-40.0 μs) and for incident laser pulse energies ranging from 20-200 mJ. In this configuration, the dominant atomic spectral features at short delay times are the hydrogen H-alpha and H-beta emission lines at 656 and 486 nm, respectively, as well as emissions from atomic oxygen liberated from the water and air and nitrogen emission lines from the air bath gas. For delay times exceeding approximately 8 μs the emission from molecular species (particularly OH and NH) created after the ablation process dominates the spectrum. Molecular emissions are found to be much less sensitive to variations in pulse energy and exhibit a temporal decay an order of magnitude slower than the atomic emission. The dependence of both atomic hydrogen and OH emission on the bath gas above the surface of the water was studied by performing the experiment at standard pressure in an atmospheric purge box. Electron densities calculated from the Stark broadening of the H-beta and H-gamma lines and plasma excitation temperatures calculated from the ratio of H-beta to H-gamma emission were measured for ablation in the three bath gases

  6. Universal buffers for use in biochemistry and biophysical experiments

    Directory of Open Access Journals (Sweden)

    Dewey Brooke

    2015-08-01

    Full Text Available The use of buffers that mimic biological solutions is a foundation of biochemical and biophysical studies. However, buffering agents have both specific and nonspecific interactions with proteins. Buffer molecules can induce changes in conformational equilibria, dynamic behavior, and catalytic properties merely by their presence in solution. This effect is of concern because many of the standard experiments used to investigate protein structure and function involve changing solution conditions such as pH and/or temperature. In experiments in which pH is varied, it is common practice to switch buffering agents so that the pH is within the working range of the weak acid and conjugate base. If multiple buffers are used, it is not always possible to decouple buffer induced change from pH or temperature induced change. We have developed a series of mixed biological buffers for protein analysis that can be used across a broad pH range, are compatible with biologically relevant metal ions, and avoid complications that may arise from changing the small molecule composition of buffers when pH is used as an experimental variable.

  7. Buffered or under Scrutiny?

    DEFF Research Database (Denmark)

    Klopf, Patricia; Nell, Phillip C.; Puck, Jonas

    – they are to a stronger extent buffered from the external environment than small firms. Thus, this paper adds to previous research by disentangling the complex effects of size on the use of political strategies – a strand of literature which has been characterized by inconsistent findings in the past.......This paper investigates political strategies of MNE subsidiaries operating in emerging markets. Our findings support previous findings of more intense political strategies in the presence of stronger institutional pressures from public and private stakeholders. Furthermore, we hypothesize...

  8. Carbon doped GaN buffer layer using propane for high electron mobility transistor applications: Growth and device results

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Nilsson, D.; Danielsson, Ö.; Pedersen, H.; Janzén, E.; Forsberg, U. [Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping 58183 (Sweden); Bergsten, J.; Rorsman, N. [Microwave Electronics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg 41296 (Sweden)

    2015-12-28

    The creation of a semi insulating (SI) buffer layer in AlGaN/GaN High Electron Mobility Transistor (HEMT) devices is crucial for preventing a current path beneath the two-dimensional electron gas (2DEG). In this investigation, we evaluate the use of a gaseous carbon gas precursor, propane, for creating a SI GaN buffer layer in a HEMT structure. The carbon doped profile, using propane gas, is a two stepped profile with a high carbon doping (1.5 × 10{sup 18 }cm{sup −3}) epitaxial layer closest to the substrate and a lower doped layer (3 × 10{sup 16 }cm{sup −3}) closest to the 2DEG channel. Secondary Ion Mass Spectrometry measurement shows a uniform incorporation versus depth, and no memory effect from carbon doping can be seen. The high carbon doping (1.5 × 10{sup 18 }cm{sup −3}) does not influence the surface morphology, and a roughness root-mean-square value of 0.43 nm is obtained from Atomic Force Microscopy. High resolution X-ray diffraction measurements show very sharp peaks and no structural degradation can be seen related to the heavy carbon doped layer. HEMTs are fabricated and show an extremely low drain induced barrier lowering value of 0.1 mV/V, demonstrating an excellent buffer isolation. The carbon doped GaN buffer layer using propane gas is compared to samples using carbon from the trimethylgallium molecule, showing equally low leakage currents, demonstrating the capability of growing highly resistive buffer layers using a gaseous carbon source.

  9. Investigating the episodic buffer

    Directory of Open Access Journals (Sweden)

    Alan Baddeley

    2010-10-01

    Full Text Available A brief account is presented of the three-component working memory model proposed by Baddeley and Hitch. This is followed by an account of some of the problems it encountered in explaining how information from different subsystems with different codes could be combined, and how it was capable of communicating with long-term memory. In order to account for these, a fourth component was proposed, the episodic buffer. This was assumed to be a multidimensional store of limited capacity that can be accessed through conscious awareness. In an attempt to test and develop the concept, a series of experiments have explored the role of working memory in the binding of visual features into objects and verbal sequences into remembered sentences. The experiments use a dual task paradigm to investigate the role of the various subcomponents of working memory in binding. In contrast to our initial assumption, the episodic buffer appears to be a passive store, capable of storing bound features and making them available to conscious awareness, but not itself responsible for the process of binding.

  10. Influence of Ambient Gas on Laser-Induced Breakdown Spectroscopy of Uranium Metal

    International Nuclear Information System (INIS)

    Zhang Dacheng; Ma Xinwen; Wang Shulong; Zhu Xiaolong

    2015-01-01

    Laser-induced breakdown spectroscopy (LIBS) is regarded as a suitable method for the remote analysis of materials in any phase, even in an environment with high radiation levels. In the present work we used the third harmonic pulse of a Nd:YAG laser for ablation of uranium metal and measured the plasma emission with a fiber-optic spectrometer. The LIBS spectra of uranium metal and their features in different ambient gases (i.e., argon, neon, oxygen, and nitrogen) at atmospheric pressure were studied. Strong continuum spectrum and several hundreds of emission lines from UI and UII were observed. It is found that the continuum spectrum observed in uranium not only comes from bremsstrahlung emission but is also due to the complex spectrum of uranium. The influence of ambient gas and the gas flow rate for ablation of uranium metal was investigated. The experimental results indicate that the intensity of the uranium lines was enhanced in argon and nitrogen. However, the intensity of uranium lines was decreased in oxygen due to the generation of UO and other oxides. The results also showed that the highest intensity of uranium lines were obtained in argon gas with a gas flow rate above 2.5 L/min. The enhanced mechanism in ambient gas and the influence of the gas flow rate were analyzed in this work. (paper)

  11. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  12. Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming.

    Science.gov (United States)

    Wallmann, Klaus; Riedel, M; Hong, W L; Patton, H; Hubbard, A; Pape, T; Hsu, C W; Schmidt, C; Johnson, J E; Torres, M E; Andreassen, K; Berndt, C; Bohrmann, G

    2018-01-08

    Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs.

  13. Inherent safety phenomenon of fission-gas induced axial extrusion in oxide and metal fueled LMFBRs

    International Nuclear Information System (INIS)

    Miles, K.J.; Kalimullah.

    1985-01-01

    The current emphasis in LMFBR design is to develop reactor systems that contain as many features as possible to limit the severity of hypothetical accidents and provide the maximum time before corrective action is required while maintaining low capital costs. One feature is the possibility of fission-gas induced axial extrusion of the fuel within the intact cladding. The potential exists for this phenomenon to enable the reactor to withstand most accidents of the TOP variety, or at least provide an extended time for corrective action to be taken. Under transient conditions which produce a heating of the fuel above its nominal operating temperature, thermal expansion of the material axially produces a negative reactivity effect. This effect is presently considered in most accident analysis codes. The phenomenon of fission-gas induced axial extrusion has received renewed interest because of the consideration of metal alloys of uranium and plutonium for the fuel in some current reactor designs

  14. Methods for improved growth of group III nitride buffer layers

    Science.gov (United States)

    Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

    2014-07-15

    Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

  15. Numerical analysis of the thermally induced flow in a strongly rotating gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Novelli, P.

    1982-04-01

    The present work is concerned with the numerical analysis of the thermally induced flow in a rapidly gas centrifuge. The primary purpose for this work is to investigate the dependence of the flow field on the thermal boundary conditions, angular speed, aspect ratio of the cylinder, holdup. Some of our results are compared with the predictions of asymptotic theories, particularly those of Sakurai-Mtsuda and Brouwers, and with the numerical results of Dickinson-Jones.

  16. Buffer moisture protection system

    International Nuclear Information System (INIS)

    Ritola, J.; Peura, J.

    2013-11-01

    With the present knowledge, bentonite blocks have to be protected from the air relative humidity and from any moisture leakages in the environment that might cause swelling of the bentonite blocks during the 'open' installation phase before backfilling. The purpose of this work was to design the structural reference solution both for the bottom of the deposition hole and for the buffer moisture protection and dewatering system with their integrated equipment needed in the deposition hole. This report describes the Posiva's reference solution for the buffer moisture protection system and the bottom plate on basis of the demands and functional requirements set by long-term safety. The reference solution with structural details has been developed in research work made 2010-2011. The structural solution of the moisture protection system has not yet been tested in practice. On the bottom of the deposition hole a copper plate which protects the lowest bentonite block from the gathered water is installed straight to machined and even rock surface. The moisture protection sheet made of EPDM rubber is attached to the copper plate with an inflatable seal. The upper part of the moisture protection sheet is fixed to the collar structures of the lid which protects the deposition hole in the disposal tunnel. The main function of the moisture protection sheet is to protect bentonite blocks from the leaking water and from the influence of the air humidity at their installation stage. The leaking water is controlled by the dewatering and alarm system which has been integrated into the moisture protection liner. (orig.)

  17. Greenhouse-gas-induced climatic change: A critical appraisal of simulations and observations

    International Nuclear Information System (INIS)

    Schlesinger, M.E.

    1990-01-01

    This book is the culmination of a Workshop on Greenhouse-Gas-Induced Climatic Change: A Critical Appraisal of Simulations and Observations which was held at the University of Massachusetts, Amherst, during 8--12 May 1989. The objectives of the Workshop were to: (1) present and evaluate the current status of climate model simulations of greenhouse-gas-induced changes of both the equilibrium and nonequilibrium (transient) climates; (2) present and assess the current status of the observations of global and regional climates from the beginning of the industrial revolution to the present, circa 1850 to 1989; (3) present reconstructions of climatic change during the last millennium to determine the ''natural variability'' of climate on the intra-century time scale; (4) critically evaluate whether or not the climate has changes from circa 1850 to 1989; and (5) compare the observations with the model simulations to ascertain whether a greenhouse-gas-induced climatic change has occurred and, if not, to estimate when in the future such a climatic change will likely become detectable against the background of the ''natural variability.''

  18. Buffer capacity of biologics--from buffer salts to buffering by antibodies.

    Science.gov (United States)

    Karow, Anne R; Bahrenburg, Sven; Garidel, Patrick

    2013-01-01

    Controlling pH is essential for a variety of biopharmaceutical process steps. The chemical stability of biologics such as monoclonal antibodies is pH-dependent and slightly acidic conditions are favorable for stability in a number of cases. Since control of pH is widely provided by added buffer salts, the current study summarizes the buffer characteristics of acetate, citrate, histidine, succinate, and phosphate buffers. Experimentally derived values largely coincide with values calculated from a model that had been proposed in 1922 by van Slyke. As high concentrated protein formulations become more and more prevalent for biologics, the self-buffering potential of proteins becomes of relevance. The current study provides information on buffer characteristics for pH ranges down to 4.0 and up to 8.0 and shows that a monoclonal antibody at 50 mg/mL exhibits similar buffer capacity as 6 mM citrate or 14 mM histidine (pH 5.0-6.0). Buffer capacity of antibody solutions scales linearly with protein concentration up to more than 200 mg/mL. At a protein concentration of 220 mg/mL, the buffer capacity resembles the buffer capacity of 30 mM citrate or 50 mM histidine (pH 5.0-6.0). The buffer capacity of monoclonal antibodies is practically identical at the process relevant temperatures 5, 25, and 40°C. Changes in ionic strength of ΔI=0.15, in contrast, can alter the buffer capacity up to 35%. In conclusion, due to efficient self-buffering by antibodies in the pH range of favored chemical stability, conventional buffer excipients could be dispensable for pH stabilization of high concentrated protein solutions. Copyright © 2013 American Institute of Chemical Engineers.

  19. Two-Buffer Simulation Games

    Directory of Open Access Journals (Sweden)

    Milka Hutagalung

    2016-07-01

    Full Text Available We consider simulation games played between Spoiler and Duplicator on two Büchi automata in which the choices made by Spoiler can be buffered by Duplicator in two different buffers before she executes them on her structure. Previous work on such games using a single buffer has shown that they are useful to approximate language inclusion problems. We study the decidability and complexity and show that games with two buffers can be used to approximate corresponding problems on finite transducers, i.e. the inclusion problem for rational relations over infinite words.

  20. Steady-state ozone concentration in radiation induced noble gas-oxygen discharges

    International Nuclear Information System (INIS)

    Elsayed-Ali, H.E.; Miley, G.H.

    1985-01-01

    Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O 2 and noble gas-O 2 -SF 6 mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10 15 eV.cm -3 .s -1 . The experimental apparatus and proceedure were previously described. The experimentally observed stead-state ozone concentrations in noble gas-O 2 discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O 2 -SF 6 mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF 6 addition. This observation was contrary to only a small increase observed after SF 6 addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O 2 discharges

  1. Steady-state ozone concentrations in radiation induced noble gas-oxygen discharges

    International Nuclear Information System (INIS)

    Elsayed-Ali, H.E.; Miley, G.H.

    1985-01-01

    Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O/sub 2/ and noble gas-o/sub 2/-SF/sub 6/ mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10/sup 15/ eV . cm/sup -3/ . s/sup -1/. The experimental apparatus and procedure were previously described. The experimentally observed steady-state ozone concentrations in noble gas-O/sub 2/ discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O/sub 2/-SF/sub 6/ mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF/sub 6/ addition. This observation was contrary to only a small increase observed after SF/sub 6/ addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O/sub 2/ discharges

  2. The Buffer and Backfill Handbook. Part 3: Models for calculation of processes and behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2003-01-15

    with gas movement through buffers and backfills. This section is intended to describe the principle of gas transport through clay elements using a simple material model. Chapter 8 deals with modeling stress/strain/time behavior of buffers and backfills. The interaction of buffer, rock and canister in deposition hole exposed to tectonically induced shearing is taken as an example of how rheological modeling can be made. Chapter 9 deals with interacting processes in buffer clay. Only few models have been clinically tested to an extent that make them recommendable. In this chapter we will confine ourselves to describe and exemplify two models, one for the mechanical behavior of unsaturated buffer with respect to heat and moisture flow, and the other dealing with geochemical transients during and after saturation of the buffer in canister deposition holes. Chapter 10 deals with the longevity of buffers and backfills. It is based on the Arrhenius-type model proposed to SKB as a working hypothesis for smectite-to-illite conversion, taking the temperature and access to dissolved potassium, as well as the activation energy, as controlling parameters. Chapter 11, finally, gives rather complete descriptions of two numerical codes for predicting the hydration rate of smectitic buffer clay and the internal strain that takes place in the evolution of the maturing clay mass, considering the interaction with the surrounding rock.

  3. Binary gas mixture adsorption-induced deformation of microporous carbons by Monte Carlo simulation.

    Science.gov (United States)

    Cornette, Valeria; de Oliveira, J C Alexandre; Yelpo, Víctor; Azevedo, Diana; López, Raúl H

    2018-07-15

    Considering the thermodynamic grand potential for more than one adsorbate in an isothermal system, we generalize the model of adsorption-induced deformation of microporous carbons developed by Kowalczyk et al. [1]. We report a comprehensive study of the effects of adsorption-induced deformation of carbonaceous amorphous porous materials due to adsorption of carbon dioxide, methane and their mixtures. The adsorption process is simulated by using the Grand Canonical Monte Carlo (GCMC) method and the calculations are then used to analyze experimental isotherms for the pure gases and mixtures with different molar fraction in the gas phase. The pore size distribution determined from an experimental isotherm is used for predicting the adsorption-induced deformation of both pure gases and their mixtures. The volumetric strain (ε) predictions from the GCMC method are compared against relevant experiments with good agreement found in the cases of pure gases. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Surface chemical reactions induced by molecules electronically-excited in the gas

    DEFF Research Database (Denmark)

    Petrunin, Victor V.

    2011-01-01

    and alignment are taking place, guiding all the molecules towards the intersections with the ground state PES, where transitions to the ground state PES will occur with minimum energy dissipation. The accumulated kinetic energy may be used to overcome the chemical reaction barrier. While recombination chemical...... be readily produced. Products of chemical adsorption and/or chemical reactions induced within adsorbates are aggregated on the surface and observed by light scattering. We will demonstrate how pressure and spectral dependencies of the chemical outcomes, polarization of the light and interference of two laser...... beams inducing the reaction can be used to distinguish the new process we try to investigate from chemical reactions induced by photoexcitation within adsorbed molecules and/or gas phase photolysis....

  5. X-ray induced gas desorption within a prototype LEP vacuum chamber

    International Nuclear Information System (INIS)

    Williams, E.M.; Le Normand, F.; Hilleret, N.; Dominichini, G.

    1982-12-01

    The present report is concerned with an experimental simulation of the process of photon induced desorption within an aluminium vacuum chamber of the same basic form as proposed for the LEP accelerator. The objectives in the work can be described in the following three-fold manner: Firstly, to establish the levels of photon induced desorption efficiency for identified gas species. Secondly, to examine the contribution of surface treatments as bakeout and glow discharge cleaning, and to correlate these responses with changes in surface activity induced by beam cleaning. Thirdly, to gain insight into the energy dependence of the desorption process so as to provide a reasonable basis for predicting conditions at the levels of critical energy in excess of 100 keV which are applicable at the full design energy of the LEP accelerator. (orig./HSI)

  6. Using fractional order method to generalize strengthening generating operator buffer operator and weakening buffer operator

    OpenAIRE

    Wu, L.; Liu, S.; Yang, Yingjie

    2016-01-01

    Traditional integer order buffer operator is extended to fractional order buffer operator, the corresponding relationship between the weakening buffer operator and the strengthening buffer operator is revealed. Fractional order buffer operator not only can generalize the weakening buffer operator and the strengthening buffer operator, but also realize tiny adjustment of buffer effect. The effectiveness of GM(1,1) with the fractional order buffer operator is validated by six cases.

  7. Mechanisms of buffer therapy resistance.

    Science.gov (United States)

    Bailey, Kate M; Wojtkowiak, Jonathan W; Cornnell, Heather H; Ribeiro, Maria C; Balagurunathan, Yoganand; Hashim, Arig Ibrahim; Gillies, Robert J

    2014-04-01

    Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.

  8. Bipolar characteristics of AlGaN/AlN/GaN/AlGaN double heterojunction structure with AlGaN as buffer layer

    International Nuclear Information System (INIS)

    Peng, Enchao; Wang, Xiaoliang; Xiao, Hongling; Wang, Cuimei; Yin, Haibo; Chen, Hong; Feng, Chun; Jiang, Lijuan; Hou, Xun; Wang, Zhanguo

    2013-01-01

    Highlights: •2DEG and 2DHG coexist in the AlGaN/AlN/GaN/AlGaN DH-structure. •The sheet densities of 2DEG and 2DHG vary with buffer Al content and GaN thickness. •The conditions for the disappearance of 2DHG are discussed. •Increasing buffer Al content provides better electron confinement. •Dislocation scattering is reduced in the DH-structure. -- Abstract: This is a theoretical study of AlGaN/AlN/GaN/AlGaN double heterojunction (DH) structure with AlGaN as buffer layer. Our calculation shows that as the buffer Al content increases, though two-dimensional electron gas (2DEG) sheet density decreases, the channel back-barrier caused by polarization-induced electric field in GaN provides better electron confinement. And under certain conditions the DH-structure shows bipolar characteristics, with an additional two-dimensional hole gas (2DHG) formed at GaN/AlGaN interface. The influence of the buffer Al content and GaN channel thickness on the 2DEG and 2DHG sheet densities are investigated, and the conditions for the disappearance of 2DHG are discussed. Also, the mobility inhibited by dislocation scattering is enhanced in DH-structure due to the enhancement of screening effect of the 2DEG

  9. Radiation effects on polymer materials. Ionizing radiation induces degradation or improvement? (2) Gas evolution by irradiation

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo

    2005-01-01

    The present article reviews gas evolution from organic polymers induced by ionizing radiations, focusing on gamma-ray irradiation of PE (polyethylene) and PP (polypropylene)-model compounds at temperatures from -77 to 55degC. In the polyolefins, the main gas evolved by irradiation is hydrogen with G-value of 3-4 at room temperatures and G(H 2 ) is 1.8 at 77K. For PE, G(H 2 ) is higher for the low-density PE than for higher-density PE. For the halogenated polymers as PVC, etc., evolved gas is hydrogen halogenated: G(HCl)=6.8 for PVC. For the case where the irradiation is accompanied with the oxidation of polymers, the de-oxygenation and formation of carboxylic radicals are remarkably high and known to emit a bad smell which depends on the thickness of oxidized layers. In conclusion, the gas evolution can be estimated by considering the molecular structure of polymer materials. (S.Ohno)

  10. Fission gas induced deformation model for FRAP-T6 and NSRR irradiated fuel test simulations

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takehiko; Sasajima, Hideo; Fuketa, Toyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Hosoyamada, Ryuji; Mori, Yukihide

    1996-11-01

    Pulse irradiation tests of irradiated fuels under simulated reactivity initiated accidents (RIAs) have been carried out at the Nuclear Safety Research Reactor (NSRR). Larger cladding diameter increase was observed in the irradiated fuel tests than in the previous fresh fuel tests. A fission gas induced cladding deformation model was developed and installed in a fuel behavior analysis code, FRAP-T6. The irradiated fuel tests were analyzed with the model in combination with modified material properties and fuel cracking models. In Test JM-4, where the cladding temperature rose to higher temperatures and grain boundary separation by the pulse irradiation was significant, the fission gas model described the cladding deformation reasonably well. The fuel had relatively flat radial power distribution and the grain boundary gas from the whole radius was calculated to contribute to the deformation. On the other hand, the power density in the irradiated LWR fuel rods in the pulse irradiation tests was remarkably higher at the fuel periphery than the center. A fuel thermal expansion model, GAPCON, which took account of the effect of fuel cracking by the temperature profile, was found to reproduce well the LWR fuel behavior with the fission gas deformation model. This report present details of the models and their NSRR test simulations. (author)

  11. Stored ions in the Paul trap. Preliminary investigations on life-time measurement of the metastable 6D3/2 state of 226Ra+, storage properties of 138Ba+ and 28N2+ at variation of the buffer-gas pressure

    International Nuclear Information System (INIS)

    Leuthner, Heiko

    2011-01-01

    Paul-traps are a widely used tool in scientific research and play an important role in atomic physics and mass spectrometry. (1) From the earth-alkaline ions only spectroscopic data of Ra + are lacking. Those are important for the test of theoretical models and for a future atomic parity violation experiment. The first part of this work describes the setting up of a Paul-trap based Laser-experiment for measuring the lifetime of the 6D 3/2 state of 226 Ra + . Basic tests with 138 Ba + ions are presented. (2) Damping and space charge effects on resonances in the stability region strongly affect the use of Paul-traps in mass spectrometry and analysis of reaction products. The second part of this work presents detailed investigations on the storage of big, buffer-gas-cooled ion clouds in two different Paul-trap experiments; the first of them uses 138 Ba + ions detected continuously by electronic and optical detection systems, the second one uses N 2 + molecular ions and an automated destructive time-of-flight-detection method. A high precision measurement with N 2 + of the first stability region of the trap not only gives the possibility of direct comparison of experimental and theoretical resonances but also provides absolute ion numbers over the whole region for the first time. Unlike previous measurements, the investigations on nonlinear resonances where done on the superimposed stability regions of 4 simultaneously stored ion species. The nonlinear resonances were studied by varying buffer gas pressure and ion number and showed collective resonances without external excitation. By varying the buffer gas pressure the spatial distribution of a Ba + -ion cloud was investigated as well as the change of the optimal storing parameters using N 2 + -ions. Optimum Pressures for catching and trapping of ions turned out to be unequal. Shape and position of externally excited collective and individual resonances were studied under variation of ion number, buffer-gas pressure

  12. Light-pressure-induced nonlinear dispersion of a laser field interacting with an atomic gas

    International Nuclear Information System (INIS)

    Grimm, R.; Mlynek, J.

    1990-01-01

    We report on detailed studies of the effect of resonant light pressure on the optical response of an atomic gas to a single monochromatic laser field. In this very elementary situation of laser spectroscopy, the redistribution of atomic velocities that is induced by spontaneous light pressure leads to a novel contribution to the optical dispersion curve of the medium. This light-pressure-induced dispersion phenomenon displays a pronounced nonlinear dependence on the laser intensity. Moreover, for a given intensity, its strength is closely related to the laser beam diameter. As most important feature, this light-pressure-induced dispersion displays an even symmetry with respect to the optical detuning from line center. As a result, the total Doppler-broadened dispersion curve of the gas can become asymmetric, and a significant shift of the dispersion line center can occur. In addition to a detailed theoretical description of the phenomenon, we report on its experimental investigation on the λ=555.6 nm 1 S 0 - 3 P 1 transition in atomic ytterbium vapor with the use of frequency-modulation spectroscopy. The experimental findings are in good quantitative agreement with theoretical predictions

  13. Condensed Fraction of an Atomic Bose Gas Induced by Critical Correlations

    International Nuclear Information System (INIS)

    Smith, Robert P.; Tammuz, Naaman; Campbell, Robert L. D.; Hadzibabic, Zoran; Holzmann, Markus

    2011-01-01

    We study the condensed fraction of a harmonically trapped atomic Bose gas at the critical point predicted by mean-field theory. The nonzero condensed fraction f 0 is induced by critical correlations which increase the transition temperature T c above T c MF . Unlike the T c shift in a trapped gas, f 0 is sensitive only to the critical behavior in the quasiuniform part of the cloud near the trap center. To leading order in the interaction parameter a/λ 0 , where a is the s-wave scattering length and λ 0 the thermal wavelength, we expect a universal scaling f 0 ∝(a/λ 0 ) 4 . We experimentally verify this scaling using a Feshbach resonance to tune a/λ 0 . Further, using the local density approximation, we compare our measurements with the universal result obtained from Monte Carlo simulations for a uniform system, and find excellent quantitative agreement.

  14. Resonance-enhanced laser-induced plasma spectroscopy: ambient gas effects

    International Nuclear Information System (INIS)

    Lui, S.L.; Cheung, N.H.

    2003-01-01

    When performing laser-induced plasma spectroscopy for elemental analysis, the sensitivity could be significantly enhanced if the plume was resonantly rekindled by a dye laser pulse. The extent of the enhancement was found to depend on the ambient gas. Air, nitrogen, helium, argon and xenon at pressures ranging from vacuum to 1 bar were investigated. In vacuum, the analyte signal was boosted because of reduced cooling, but it soon decayed as the plume freely expanded. By choosing the right ambient gas at the right pressure, the expanding plume could be confined as well as thermally insulated to maximize the analyte signal. For instance, an ambient of 13 mbar xenon yielded a signal-to-noise ratio of 110. That ratio was 53 when the pellet was ablated in air, and decreased further to 5 if the dye laser was tuned off resonance

  15. Surface-Induced Near-Field Scaling in the Knudsen Layer of a Rarefied Gas

    Science.gov (United States)

    Gazizulin, R. R.; Maillet, O.; Zhou, X.; Cid, A. Maldonado; Bourgeois, O.; Collin, E.

    2018-01-01

    We report on experiments performed within the Knudsen boundary layer of a low-pressure gas. The noninvasive probe we use is a suspended nanoelectromechanical string, which interacts with He 4 gas at cryogenic temperatures. When the pressure P is decreased, a reduction of the damping force below molecular friction ∝P had been first reported in Phys. Rev. Lett. 113, 136101 (2014), 10.1103/PhysRevLett.113.136101 and never reproduced since. We demonstrate that this effect is independent of geometry, but dependent on temperature. Within the framework of kinetic theory, this reduction is interpreted as a rarefaction phenomenon, carried through the boundary layer by a deviation from the usual Maxwell-Boltzmann equilibrium distribution induced by surface scattering. Adsorbed atoms are shown to play a key role in the process, which explains why room temperature data fail to reproduce it.

  16. Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

    International Nuclear Information System (INIS)

    Wells, Beric E.; Cuta, Judith M.; Hartley, Stacey A.; Mahoney, Lenna A.; Meyer, Perry A.; Stewart, Charles W.

    2002-01-01

    Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105, and AW-101 to the vitrification plant beginning about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both of these operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated

  17. Effects of Post-Treatment Hydrogen Gas Inhalation on Uveitis Induced by Endotoxin in Rats.

    Science.gov (United States)

    Yan, Weiming; Chen, Tao; Long, Pan; Zhang, Zhe; Liu, Qian; Wang, Xiaocheng; An, Jing; Zhang, Zuoming

    2018-06-07

    BACKGROUND Molecular hydrogen (H2) has been widely reported to have benefiicial effects in diverse animal models and human disease through reduction of oxidative stress and inflammation. The aim of this study was to investigate whether hydrogen gas could ameliorate endotoxin-induced uveitis (EIU) in rats. MATERIAL AND METHODS Male Sprague-Dawley rats were divided into a normal group, a model group, a nitrogen-oxygen (N-O) group, and a hydrogen-oxygen (H-O) group. EIU was induced in rats of the latter 3 groups by injection of lipopolysaccharide (LPS). After that, rats in the N-O group inhaled a gas mixture of 67% N2 and 33% O2, while those in the H-O group inhaled a gas mixture of 67% H2 and 33% O2. All rats were graded according to the signs of uveitis after electroretinography (ERG) examination. Protein concentration in the aqueous humor (AqH) was measured. Furthermore, hematoxylin-eosin staining and immunostaining of anti-ionized calcium-binding adapter molecule 1 (Iba1) in the iris and ciliary body (ICB) were carried out. RESULTS No statistically significant differences existed in the graded score of uveitis and the b-wave peak time in the Dark-adapted 3.0 ERG among the model, N-O, and H-O groups (P>0.05), while rats of the H-O group showed a lower concentration of AqH protein than that of the model or N-O group (P0.05), while the activation of microglia cells in the H-O group was somewhat reduced (Ptreatment hydrogen gas inhalation did not ameliorate the clinical signs, or reduce the infiltrating cells of EIU. However, it inhibited the elevation of protein in the AqH and reduced the microglia activation.

  18. Buffer mass test - Site documentation

    International Nuclear Information System (INIS)

    Pusch, R.

    1983-10-01

    The purpose of this report is to compile test site data that are assumed to be of importance for the interpretation of the Buffer Mass Test. Since this test mainly concerns water uptake and migration processes in the integrated rock/backfill system and the development of temperature fields in this system, the work has been focused on the constitution and hydrology of the rock. The major constitutional rock feature of interest for the BMT is the frequency and distribution of joints and fractures. The development of models for water uptake into the highly compacted bentonite in the heater holes requires a very detailed fracture survey. The present investigation shows that two of the holes (no. 1 and 2) are located in richly fractured rock, while the others are located in fracture-poor to moderately fractured rock. The hydrological conditions of the rock in the BMT area are characterized by water pressures of as much as 100 m water head at a few meters distance from the test site. The average hydraulic conductivity of the rock that confines the BMT tunnel has been estimated at about 10 -10 m/s by Lawrence Laboratory. The actual distribution of the water that enters the tunnel has been estimated by observing the successive moistening after having switched off the ventilation, and this has offered basis of predicting the rate and uniformity of the water uptake in the tunnel backfill. As to the heater holes the detailed fracture patterns and various inflow measurements have yielded a similar basis. The report also gives major data on the rock temperature, gas conditions, mineralogy, rock mechanics, and groundwater chemistry for BMT purposes. (author)

  19. Simulation study on single event burnout in linear doping buffer layer engineered power VDMOSFET

    International Nuclear Information System (INIS)

    Jia Yunpeng; Su Hongyuan; Hu Dongqing; Wu Yu; Jin Rui

    2016-01-01

    The addition of a buffer layer can improve the device's secondary breakdown voltage, thus, improving the single event burnout (SEB) threshold voltage. In this paper, an N type linear doping buffer layer is proposed. According to quasi-stationary avalanche simulation and heavy ion beam simulation, the results show that an optimized linear doping buffer layer is critical. As SEB is induced by heavy ions impacting, the electric field of an optimized linear doping buffer device is much lower than that with an optimized constant doping buffer layer at a given buffer layer thickness and the same biasing voltages. Secondary breakdown voltage and the parasitic bipolar turn-on current are much higher than those with the optimized constant doping buffer layer. So the linear buffer layer is more advantageous to improving the device's SEB performance. (paper)

  20. Evidence for the concentration induced extinction of gas sensitivity in amorphous and nanostructured Te thin films

    International Nuclear Information System (INIS)

    Tsiulyanu, D.; Mocreac, O.; Enachi, M.; Volodina, G.

    2013-01-01

    The extinction of sensitivity to nitrogen dioxide induced by high gas concentration have been observed in ultrathin tellurium films. The phenomenon becomes apparent in both continuous and nanostructured films shown by AFM, SEM and XRD analyses to be in amorphous state. Sensitivity of 30 nm thickness Te film decreases near linearly with concentration increase between 150 and 500 ppb of nitrogen dioxide. The results are explained in terms of formation of a nitrogen dioxide catalytic gate in which a molecule adsorbs (and desorbs) without reacting. (authors)

  1. Electrodialysis operation with buffer solution

    Science.gov (United States)

    Hryn, John N [Naperville, IL; Daniels, Edward J [Orland Park, IL; Krumdick, Greg K [Crete, IL

    2009-12-15

    A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

  2. Comparing and contrasting Holocene and Eemian warm periods with greenhouse-gas-induced warming

    International Nuclear Information System (INIS)

    MacCracken, M.C.; Kutzbach, J.

    1990-01-01

    Periods of the past that are estimated to have been warmer than present are of great potential interest for comparison with simulations of future climates associated with greenhouse-gas-induced warming. Certain features of the climates of the mid-Holocene and Eemian periods, both interglacial maxima, are described. The simulated climatic responses to both types of forcing, in terms of land/ocean and latitudinal averages, are also compared. The zonal average and annual (or seasonal) average radiation fluxes associated with the different-from-present orbital conditions that existed for those interglacials are compared to the radiation flux associated with CO 2 -induced warming. There are some similarities but also significant differences in the two types of radiation flux perturbations, and there are both similarities and differences in the simulated climatic responses

  3. Numerical modeling of self-limiting and self-enhancing caprock alteration induced by CO2 storage in a depleted gas reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianfu; Gherardi, Fabrizio; Xu, Tianfu; Pruess, Karsten

    2007-09-07

    This paper presents numerical simulations of reactive transport which may be induced in the caprock of an on-shore depleted gas reservoir by the geological sequestration of carbon dioxide. The objective is to verify that CO{sub 2} geological disposal activities currently being planned for the study area are safe and do not induce any undesired environmental impact. In our model, fluid flow and mineral alteration are induced in the caprock by penetration of high CO{sub 2} concentrations from the underlying reservoir, where it was assumed that large amounts of CO{sub 2} have already been injected at depth. The main focus is on the potential effect of precipitation and dissolution processes on the sealing efficiency of caprock formations. Concerns that some leakage may occur in the investigated system arise because the seal is made up of potentially highly-reactive rocks, consisting of carbonate-rich shales (calcite+dolomite averaging up to more than 30% of solid volume fraction). Batch simulations and multi-dimensional 1D and 2D modeling have been used to investigate multicomponent geochemical processes. Numerical simulations account for fracture-matrix interactions, gas phase participation in multiphase fluid flow and geochemical reactions, and kinetics of fluid-rock interactions. The geochemical processes and parameters to which the occurrence of high CO{sub 2} concentrations are most sensitive are investigated by conceptualizing different mass transport mechanisms (i.e. diffusion and mixed advection+diffusion). The most relevant mineralogical transformations occurring in the caprock are described, and the feedback of these geochemical processes on physical properties such as porosity is examined to evaluate how the sealing capacity of the caprock could evolve in time. The simulations demonstrate that the occurrence of some gas leakage from the reservoir may have a strong influence on the geochemical evolution of the caprock. In fact, when a free CO{sub 2

  4. Stress and Damage Induced Gas Flow Pattern and Permeability Variation of Coal from Songzao Coalfield in Southwest China

    Directory of Open Access Journals (Sweden)

    Minghui Li

    2016-05-01

    Full Text Available The permeability of coal is a critical parameter in estimating the performance of coal reservoirs. Darcy’s law describes the flow pattern that the permeability has a linear relationship with the flow velocity. However, the stress induced deformation and damage can significantly influence the gas flow pattern and permeability of coal. Coals from Songzao coalfield in Chongqing, southwest China were collected for the study. The gas flow velocities under different injection gas pressures and effective stresses in the intact coal and damaged coal were tested using helium, incorporating the role of gas flow pattern on the permeability of coal. The relationships between the flow velocity and square of gas pressure gradient were discussed, which can help us to investigate the transformation conditions of gas linear flow and gas nonlinear flow in the coal. The results showed that the gas flow in the intact coal existed pseudo-initial flow rate under low effective stress. The low-velocity non-Darcy gas flow gradually occurred and the start-up pressure gradient increased in the coal as the effective stress increased. The gas flow rate in the damaged coal increased nonlinearly as the square of pressure gradient increased under low effective stress. The instability of gas flow caused by high ratio of injection gas pressure over effective stress in the damaged coal contributed to the increase of the gas flow rate. As the effective stress increased, the increase of gas flow rate in coal turned to be linear. The mechanisms of the phenomena were explored according to the experimental results. The permeability of coal was corrected based on the relationships between the flow velocity and square of gas pressure gradient, which showed advantages in accurately estimating the performance of coal reservoirs.

  5. Heat conductivity of buffer materials

    International Nuclear Information System (INIS)

    Boergesson, L.; Fredrikson, Anders; Johannesson, L.E.

    1994-11-01

    The report deals with the thermal conductivity of bentonite based buffer materials. An improved technique for measuring the thermal conductivity of buffer materials is described. Measurements of FLAC calculations applying this technique have led to a proposal of how standardized tests should be conducted and evaluated. The thermal conductivity of bentonite with different void ratio and degree of water saturation has been determined in the following different ways: * Theoretically according to three different investigations by other researchers. * Laboratory measurements with the proposed method. * Results from back-calculated field tests. Comparison and evaluation showed that these results agreed very well, when the buffer material was almost water saturated. However, the influence of the degree of saturation was not very well predicted with the theoretical methods. Furthermore, the field tests showed that the average thermal conductivity in situ of buffer material (compacted to blocks) with low degree of water saturation was lower than expected from laboratory tests. 12 refs, 29 figs, 11 tabs

  6. Buffers and vegetative filter strips

    Science.gov (United States)

    Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

    2008-01-01

    This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.

  7. Determination of methylmercury in fish tissue by gas chromatography with microwave-induced plasma atomic emission spectrometry after derivatization with sodium tetraphenylborate

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, H.E.L.; Leonel, L.V. [Comissao Nacional de Energia Nuclear - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte (Brazil)

    2000-03-01

    The detection of methylmercury species (MeHg) in fish tissue was investigated. Samples were digested with KOH-methanol and acidified prior to extraction with methylene chloride. MeHg was back-extracted from the organic phase into water. An aliquot of this aqueous solution (buffered to pH 5) was subjected to derivatization with sodium tetraphenylborate (NaBPh{sub 4}) and then extracted with toluene. The organic phase containing MePhHg was injected into a gas chromatograph (GC) which is on-line with a microwave-induced plasma atomic emission spectrometer (MIP-AED). The quantification limit was about 0.6 {mu}g/g and 0.1 {mu}g/g of MeHg (as Hg) for 0.08 g of freeze-dried fish powder and 0.5 g of fresh samples, respectively. Two certified reference materials, CRM 464 (tuna fish) from Community Bureau of Reference-BCR and DORM-2 (dogfish muscle) from National Research Council Canada-NRC were selected for checking the accuracy of the method. This methodology was applied to the determination of MeHg in some kinds of fish from the Carmo river with alluvial gold recovery activities (''garimpos'') in Mariana, Minas Gerais, Brazil. (orig.)

  8. Determination of methylmercury in fish tissue by gas chromatography with microwave-induced plasma atomic emission spectrometry after derivatization with sodium tetraphenylborate.

    Science.gov (United States)

    Palmieri, H E; Leonel, L V

    2000-03-01

    The detection of methylmercury species (MeHg) in fish tissue was investigated. Samples were digested with KOH-methanol and acidified prior to extraction with methylene chloride. MeHg was back-extracted from the organic phase into water. An aliquot of this aqueous solution (buffered to pH 5) was subjected to derivatization with sodium tetraphenylborate (NaBPh4) and then extracted with toluene. The organic phase containing MePhHg was injected into a gas chromatograph (GC) which is on-line with a microwave-induced plasma atomic emission spectrometer (MIP-AED). The quantification limit was about 0.6 microg/g and 0.1 microg/g of MeHg (as Hg) for 0.08 g of freeze-dried fish powder and 0.5 g of fresh samples, respectively. Two certified reference materials, CRM 464 (tuna fish) from Community Bureau of Reference-BCR and DORM-2 (dogfish muscle) from National Research Council Canada-NRC were selected for checking the accuracy of the method. This methodology was applied to the determination of MeHg in some kinds of fish from the Carmo river with alluvial gold recovery activities ("garimpos") in Mariana, Minas Gerais, Brazil.

  9. MATHEMATICAL MODELLING OF QUAZISTEADY MODE OF BEARING AIR BUFFER FILLING

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2014-01-01

    Full Text Available Summary. Today the only way to eliminate contact with the product during the manufacturing process is to provide a support surface under its support surface air buffer layer formed due to the expiration of the working environment through holes perforated gas distribution grids forms. There proposed the method of contactless formation of products consisting of composite materials by the means of air buffer in the article. The results of theoretical and experimental investigations of hydro-gas-dynamic processes occurring when casting of organic- mineral composite material onto the bearing air buffer expressed in the form of mathematical description realizing original hypotheses reflected in the choice of transformation algorithm and limiting conditions are presented. On the base of obtained mathematical model the algorithm of calculation of optimum parameters of transporting systems with discretely powered gas buffer is developed. The method of deduction of a semi-finished product on the gas buffer, which allows to level the pressure field under the bearing surface of the deduction object due to the usage of devices of pseudo fluidized granular material in pneumatic chambers is offered. The application of this method allows to eliminate the possibility of contact between the composite material and the working surface of the equipment and also to reduce the cost of production of pneumatic devices, to improve operational characteristics of this equipment. Submitted depending allowed to develop the methodology and implementation of engineering calculation device for non-contact casting composite materials on air buffer, semi-industrial and industrial variants were created and put into production.

  10. A precipitation-induced landslide susceptibility model for natural gas transmission pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Finley, Jason P. [Fugro William Lettis and Associates, Inc., Valencia, California (United States); Slayter, David L.; Hitchcock, Chris S. [Fugro William Lettis and Associates, Inc., Walnut Creek, California (United States); Lee, Chih-Hung [Pacific Gas and Electric Company, Gas Systems Integrity Management, Walnut Creek, California (United States)

    2010-07-01

    Landslides related to heavy rainfall can cause extensive damage to natural gas transmission pipelines. Fugro William Lettis and Associates Inc. have developed and implemented a geographic information system (GIS) model that evaluates near real-time precipitation-induced landslide susceptibility. The model incorporates state-wide precipitation data and geologically-based landslide classifications to produce rapid landslide risk evaluation for Pacific Gas and Electric Company's (PGandE) gas transmission system during winter rain storms in California. The precipitation data include pre-storm event quantitative precipitation forecasts (QPF) and post-storm event quantitative precipitation estimate (QPE) from the United States National Oceanic and Atmospheric Administration (NOAA). The geologic classifications are based on slope, susceptible geologic formations, and the locations of historic or known landslide occurrences. Currently the model is calibrated using qualitative measures. This paper describes the development of the model algorithm and input data, model results, calibration efforts, and the on-going research and landslide collection warranted for continued refinement of the model.

  11. Investigation of Gas Seeding for Planar Laser-Induced Fluorescence in Hypersonic Boundary Layers

    Science.gov (United States)

    Arisman, C. J.; Johansen, C. T.; Bathel, B. F.; Danehy, P. M.

    2015-01-01

    Numerical simulations of the gas-seeding strategies required for planar laser-induced fluorescence in a Mach 10 (approximately Mach 8.2 postshock) airflow were performed. The work was performed to understand and quantify the adverse effects associated with gas seeding and to assess various types of seed gas that could potentially be used in future experiments. In prior experiments, NO and NO2 were injected through a slot near the leading edge of a flatplate wedge model used in NASA Langley Research Center's 31 in. Mach 10 air tunnel facility. In this paper, nitric oxide, krypton, and iodine gases were simulated at various injection rates. Simulations showing the deflection of the velocity boundary layer for each of the cases are presented. Streamwise distributions of velocity and concentration boundary-layer thicknesses, as well as vertical distributions of velocity, temperature, and mass distributions, are presented for each of the cases. A comparison between simulated streamwise velocity profiles and experimentally obtained molecular tagging velocimetry profiles using a nitric oxide seeding strategy is performed to verify the influence of such a strategy on the boundary layer. The relative merits of the different seeding strategies are discussed. The results from a custom solver based on OpenFOAM version 2.2.1 are compared against results obtained from ANSYS® Fluent version 6.3.

  12. Programmable pH buffers

    Science.gov (United States)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  13. Addressing a Common Misconception: Ammonium Acetate as Neutral pH "Buffer" for Native Electrospray Mass Spectrometry

    Science.gov (United States)

    Konermann, Lars

    2017-09-01

    Native ESI-MS involves the transfer of intact proteins and biomolecular complexes from solution into the gas phase. One potential pitfall is the occurrence of pH-induced changes that can affect the analyte while it is still surrounded by solvent. Most native ESI-MS studies employ neutral aqueous ammonium acetate solutions. It is a widely perpetuated misconception that ammonium acetate buffers the analyte solution at neutral pH. By definition, a buffer consists of a weak acid and its conjugate weak base. The buffering range covers the weak acid pKa ± 1 pH unit. NH4 + and CH3-COO- are not a conjugate acid/base pair, which means that they do not constitute a buffer at pH 7. Dissolution of ammonium acetate salt in water results in pH 7, but this pH is highly labile. Ammonium acetate does provide buffering around pH 4.75 (the pKa of acetic acid) and around pH 9.25 (the pKa of ammonium). This implies that neutral ammonium acetate solutions electrosprayed in positive ion mode will likely undergo acidification down to pH 4.75 ± 1 in the ESI plume. Ammonium acetate nonetheless remains a useful additive for native ESI-MS. It is a volatile electrolyte that can mimic the solvation properties experienced by proteins under physiological conditions. Also, a drop from pH 7 to around pH 4.75 is less dramatic than the acidification that would take place in pure water. It is hoped that the habit of referring to pH 7 solutions as ammonium acetate "buffer" will disappear from the literature. Ammonium acetate "solution" should be used instead. [Figure not available: see fulltext.

  14. Laboratory simulations of fluid/gas induced micro-earthquakes: application to volcano seismology.

    Directory of Open Access Journals (Sweden)

    Philip Michael Benson

    2014-11-01

    Full Text Available Understanding different seismic signals recorded in active volcanic regions allows geoscientists to derive insight into the processes that generate them. A key type is known as Low Frequency or Long Period (LP event, generally understood to be generated by different fluid types resonating in cracks and faults. The physical mechanisms of these signals have been linked to either resonance/turbulence within fluids, or as a result of fluids ‘sloshing’ due to a mixture of gas and fluid being present in the system. Less well understood, however, is the effect of the fluid type (phase on the measured signal. To explore this, we designed an experiment in which we generated a precisely controlled liquid to gas transition in a closed system by inducing rapid decompression of fluid-filled fault zones in a sample of basalt from Mt. Etna Volcano, Italy. We find that fluid phase transition is accompanied by a marked frequency shift in the accompanying microseismic dataset that can be compared to volcano seismic data. Moreover, our induced seismic activity occurs at pressure conditions equivalent to hydrostatic depths of 200 to 750 meters. This is consistent with recently measured dominant frequencies of LP events and with numerous models.

  15. Laser-induced breakdown ignition in a gas fed two-stroke engine

    Science.gov (United States)

    Loktionov, E. Y.; Pasechnikov, N. A.; Telekh, V. D.

    2018-01-01

    Laser-induced ignition for internal combustion engines is investigated intensively after demonstration of a compact ‘laser plug’ possibility. Laser spark benefits as compared to traditional spark plugs are higher compression rate, and possibility of almost any fuel ignition, so lean mixtures burning with lower temperatures could reduce harmful exhausts (NO x , CH, etc). No need in electrode and possibility for multi-point, linear or circular ignition can make combustion even more effective. Laser induced combustion wave appears faster and is more stable in time, than electric one, so can be used for ramjets, chemical thrusters, and gas turbines. To the best of our knowledge, we have performed laser spark ignition of a gas fed two-stroke engine for the first time. Combustion temperature and pressure, exhaust composition, ignition timing were investigated at laser and compared to a regular electric spark ignition in a two-stroke model engine. Presented results show possibility for improvement of two-stroke engines performance, in terms of rotation rate increase and NO x emission reduction. Such compact engines using locally mined fuel could be highly demanded in remote Arctic areas.

  16. Interfacial instability induced by a shock wave in a gas-liquid horizontal stratified system

    International Nuclear Information System (INIS)

    Sutradhar, S.C.; Chang, J.S.; Yoshida, H.

    1987-01-01

    The experiments are performed in a rectangular lucite duct equipped with the facility of generating shock waves. Piezo-type pressure transducers are used to monitor the strength and propagation velocity of the shock wave. As the liquid phase has high sound velocity, a prepulse wave system of flow amplitude travels in this phase at a speed faster than the principal shock wave. The magnitude of the transmitted wave in the liquid phase is estimated using a transmission coefficient for gas-liquid system. From the initial pressure ratio of the shock wave, the amplitude of the prepulse as well as the induced interfacial fluid velocity are calculated. The wave length and height of the ripples during the passage of the shock wave are estimated for a specific strength of shock wave moving through the phases. From the high speed photographs, the wave length of the ripples can be assessed. The interfacial friction factor is calculated using colebrook's equation for high speed flow. At least five distinct phenomena are observed to exist during the propagation of a shock wave. These are - (1) the energy carried by the pre-pulse is utilized in perturbing the interface; (2) shock wave induces a mass velocity at the interface; (3) the wavelength of the ripples at the interface is the product of induced interfacial mass velocity and the time period of the prepulse; (4) a portion of the liquid mass of the perturbed interface is entrained in the gas phase may be due to the hydrodynamic lift in that phase; and finally (5) waves with long wavelength are established at the interface

  17. Hydrogen Gas Inhalation Attenuates Seawater Instillation-Induced Acute Lung Injury via the Nrf2 Pathway in Rabbits.

    Science.gov (United States)

    Diao, Mengyuan; Zhang, Sheng; Wu, Lifeng; Huan, Le; Huang, Fenglou; Cui, Yunliang; Lin, Zhaofen

    2016-12-01

    Seawater instillation-induced acute lung injury involves oxidative stress and apoptosis. Although hydrogen gas inhalation is reportedly protective in multiple types of lung injury, the effect of hydrogen gas inhalation on seawater instillation-induced acute lung injury remains unknown. This study investigated the effect of hydrogen gas on seawater instillation-induced acute lung injury and explored the mechanisms involved. Rabbits were randomly assigned to control, hydrogen (2 % hydrogen gas inhalation), seawater (3 mL/kg seawater instillation), and seawater + hydrogen (3 mL/kg seawater instillation + 2 % hydrogen gas inhalation) groups. Arterial partial oxygen pressure and lung wet/dry weight ratio were detected. Protein content in bronchoalveolar lavage fluid (BALF) and serum as well as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels were determined. Hematoxylin-eosin staining was used to monitor changes in lung specimens, and malondialdehyde (MDA) content and myeloperoxidase (MPO) activity were assayed. In addition, NF-E2-related factor (Nrf) 2 and heme oxygenase (HO)-1 mRNA and protein expression were measured, and apoptosis was assessed by measuring caspase-3 expression and using terminal deoxy-nucleotidyl transferase dUTP nick end-labeling (TUNEL) staining. Hydrogen gas inhalation markedly improved lung endothelial permeability and decreased both MDA content and MPO activity in lung tissue; these changes were associated with decreases in TNF-α, IL-1β, and IL-6 in BALF. Hydrogen gas also alleviated histopathological changes and cell apoptosis. Moreover, Nrf2 and HO-1 expressions were significantly activated and caspase-3 expression was inhibited. These results demonstrate that hydrogen gas inhalation attenuates seawater instillation-induced acute lung injury in rabbits and that the protective effects observed may be related to the activation of the Nrf2 pathway.

  18. Optimization of combustion chamber geometry for natural gas engines with diesel micro-pilot-induced ignition

    International Nuclear Information System (INIS)

    Wang, Bin; Li, Tie; Ge, Linlin; Ogawa, Hideyuki

    2016-01-01

    Highlights: • Combustion chamber geometry is optimized to reduce the HC/CO emissions. • CFD model is calibrated against the spray visualization and engine bench test data. • Design space is explored by the multi-objective NSGA-II with Kriging meta-model. • HC and CO emissions are respectively reduced by 56.47% and 33.55%. - Abstract: Smokeless, low nitrogen oxides (NOx), and high thermal efficiency have been achieved through the lean-burn concept for natural gas engine with diesel micro-pilot-induced ignition (MPII). However, the combustion chamber is usually not specialized for natural gas combustion, and increases in the unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are still a challenge for this type of engines. This paper describes optimization of the combustion chamber geometry to reduce the HC and CO emissions and improve the combustion efficiency in the MPII natural gas engine. The 3-D computational fluid dynamics (CFD) simulation model coupled with a chemical reaction mechanism is described. The temporal development of the short-pulsed diesel spray in a high pressure constant-volume vessel is measured and used to calibrate the spray model in the CFD simulation. The simulation models are validated by the experimental data of the in-cylinder pressure trace, apparent heat release rate (AHRR) and exhaust gas emissions from a single-cylinder MPII natural gas engine. To generate the various combustion chamber geometries, the bowl outline is parameterized by the two cubic Bezier curves while keeping the compression ratio constant. The available design space is explored by the multi-objective non-dominated sorting genetic algorithm II (NSGA-II) with Kriging-based meta-model. With the optimization, the HC and CO emissions are reduced by 56.47% and 33.55%, respectively, while the NOx emissions, the maximum rate of pressure rise and the gross indicated thermal efficiency that are employed as the constraints are slightly improved. Finally, the

  19. A sequential approach to control gas for the extraction of multi-gassy coal seams from traditional gas well drainage to mining-induced stress relief

    International Nuclear Information System (INIS)

    Kong, Shengli; Cheng, Yuanping; Ren, Ting; Liu, Hongyong

    2014-01-01

    Highlights: • The gas reservoirs characteristics are measured and analyzed. • A sequential approach to control gas of multi-gassy coal seams is proposed. • The design of gas drainage wells has been improved. • The utilization ways of different concentrations of gas production are shown. - Abstract: As coal resources become exhausted in shallow mines, mining operations will inevitably progress from shallow depth to deep and gassy seams due to increased demands for more coal products. However, during the extraction process of deeper and gassier coal seams, new challenges to current gas control methods have emerged, these include the conflict between the coal mine safety and the economic benefits, the difficulties in reservoirs improvement, as well as the imbalance between pre-gas drainage, roadway development and coal mining. To solve these problems, a sequential approach is introduced in this paper. Three fundamental principles are proposed: the mining-induced stress relief effect of the first-mined coalbed should be sufficient to improve the permeability of the others; the coal resource of the first-mined seams must be abundant to guarantee the economic benefits; the arrangement of the vertical wells must fit the underground mining panel. Tunlan coal mine is taken as a typical example to demonstrate the effectiveness of this approach. The approach of integrating surface coalbed methane (CBM) exploitation with underground gas control technologies brings three major benefits: the improvement of underground coal mining safety, the implementation of CBM extraction, and the reduction of greenhouse gas emissions. This practice could be used as a valuable example for other coal mines having similar geological conditions

  20. Design of a tritium gas cell for beta-ray induced X-ray spectrometry using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Masanori, E-mail: masahara@ctg.u-toyama.ac.jp [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Abe, Shinsuke; Matsuyama, Masao [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Aso, Tsukasa [Electronics and Computer Engineering, National Institute of Technology, Toyama College, 1-2 Ebie-neriya, Imizu City, Toyama 933-0293 (Japan); Tatenuma, Katsuyoshi; Kawakami, Tomohiko; Ito, Takeshi [KAKEN Company Limited, 1044 Horimachi, Mito City, Ibaraki 310-0903 (Japan)

    2017-06-15

    Highlights: • Beta-ray induced X-ray spectrometry (BIXS) is a method for tritium gas analysis. • Gas cell for BIXS was designed by Monte Carlo simulations. • The optimum thickness of the gold layer on a beryllium window was around 150 nm. • This simulation model considered the self-absorption with increasing the cell length. - Abstract: One of the methods used for tritium gas analysis is beta-ray induced X-ray spectrometry (BIXS). Gas cell design is important in this method. The structure of the gas cell for BIXS was optimized by Monte Carlo simulation of beta-ray induced X-ray spectra in various window geometries using the Geant4 tool kit (version 10.01.p02). The simulated spectrum from tritium decay fitted the observed one, and the simulation model was used to obtain the cell parameters for BIXS. The optimum thickness of the gold layer on a beryllium window was around 150 nm. This simulation model also considered the relationship between self-absorption by hydrogen gas and the cell length. Self-absorption increased with increasing cell length and the relationship between the sample pressure and cell length was formulated.

  1. Evidence for the buffer zone in a plasma accelerator

    International Nuclear Information System (INIS)

    Thomas, K.A.; Clothiaux, E.J.

    1991-01-01

    The existence of an absorbing layer, or buffer zone, of weakly ionized gas between the rear of the projectile and the front of the plasma arc armature in a plasma accelerator has been postulated. In the studies reported here a technique for finding the position of the projectile as a function of time is given and compared to the plasma armature position as determined by inductive probes. Analyses of these signals provide the basis for a description of the in-bore motion of the projectile with respect to the plasma arc armature. The experimental evidence appears to support the existence of a buffer zone

  2. Irradiation induced aerosol formation in flue gas: experiments on low doses

    International Nuclear Information System (INIS)

    Maekelae, J.M.

    1992-01-01

    Laboratory experiments on irradiation induced aerosol formation from gaseous sulphur dioxide in humid air are presented. This work is connected to the aerosol particle formation process in the electron beam technique for cleaning flue gas. As a partial process of this method primary products of the radiolysis of water vapour convert sulphur dioxide into gaseous sulphuric acid which then nucleates with water vapour forming small acid droplets. This experimental work has been performed on relatively low absorbed doses. Aerosol particle formation is strongly dependent on dose. In the experiments, the first aerosol particles were detected already on absorbed doses of 0.1-10 mGy. The particle size in these cases is in the so-called ultrafine size range (1-20 nm). In this article three experimental set-ups with some characteristic results are presented. (Author)

  3. Effect of radiation-induced substrate defects on microstrip gas chamber gain behaviour

    International Nuclear Information System (INIS)

    Pallares, A.; Brom, J.M.; Bergdolt, A.M.; Coffin, J.; Eberle, H.; Sigward, M.H.; Fontaine, J.C.; Barthe, S.; Schunck, J.P.

    1998-01-01

    The aim of this work was to quantify the influence of radiation-induced substrate defects on microstrip gas chamber (MSGC) gain behaviour. The first part of this paper focuses on radiation effects on a typical MSGC substrate: Desag D263 glass. Defect generation was studied for Desag D263 with pure silica (Suprasil 1) as a reference. We studied the evolution of defect concentration with respect to accumulated doses up to 480 kGy. Annealing studies of defects in Desag D263 were also performed. In the second part, the radiation sensitivity of Desag D263 glass has been linked to the behaviour of the detector under irradiation. Comparative gain measurements were taken before and after substrate irradiation at 10 and 80 kGy the minimal dose received during LHC operation and the dose for which defect density is maximum (respectively). (orig.)

  4. Effect of radiation-induced substrate defects on microstrip gas chamber gain behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pallares, A.; Brom, J.M.; Bergdolt, A.M.; Coffin, J.; Eberle, H.; Sigward, M.H. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Fontaine, J.C. [Universite de Haute Alsace, GRPHE, 61 rue Albert Camus, 68093 Mulhouse Cedex (France); Barthe, S.; Schunck, J.P. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France)

    1998-08-01

    The aim of this work was to quantify the influence of radiation-induced substrate defects on microstrip gas chamber (MSGC) gain behaviour. The first part of this paper focuses on radiation effects on a typical MSGC substrate: Desag D263 glass. Defect generation was studied for Desag D263 with pure silica (Suprasil 1) as a reference. We studied the evolution of defect concentration with respect to accumulated doses up to 480 kGy. Annealing studies of defects in Desag D263 were also performed. In the second part, the radiation sensitivity of Desag D263 glass has been linked to the behaviour of the detector under irradiation. Comparative gain measurements were taken before and after substrate irradiation at 10 and 80 kGy the minimal dose received during LHC operation and the dose for which defect density is maximum (respectively). (orig.) 26 refs.

  5. Modeling of SQS propagation induced by alpha ray in gas counters

    International Nuclear Information System (INIS)

    Nohtomi, A.; Narita, K.; Sakae, T.; Uozumi, Y.; Matoba, M.

    1995-01-01

    With reference to optical images of the self-quenching streamer (SQS), the authors have already proposed a possible mechanism of SQSs induced by α-rays. To check the validity of the mechanism, they have been designing a model for the computer simulation of the SQS propagation based on the newly proposed mechanism. In the present modeling, in order to calculate the growth of the discharge, a set of continuity equations for electrons and ions is numerically solved in a two-dimensional space. An electron supply process from the α-ray ionization track is assumed to be the dominant process for the streamer development instead of the conventional electron-supply process which is based on the photoionization in the gas media. The streamer propagation is simulated under the concept of two-region model. A first comparison between computed and experimental results shows a good agreement

  6. Thermophysical tests of buffer materials

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokyo (Japan); Taniguchi, Wataru

    1999-03-01

    Thermodynamic properties of buffer materials were measured for putting in order thermodynamic constants to be used in the near-field thermal analysis. The thermal diffusivity and thermal conductivity were measured as functions of the water content and temperature to deduce the specific heat. The thermal conductivity and specific heat varied significantly as the water content changed. Obtained values of the specific heat agreed well the expected values calculated based on the constituents of the buffer material. Temperature dependence of the thermodynamic constants was found small below 90degC. From the findings, the thermal conductivity and specific heat of the buffer material were formulated as functions of the water content. Thermodynamic study of powdery bentonite was carried out as well with a purpose of use for filling apertures in the artificial barrier. (H. Baba)

  7. Effects of gas flow on oxidation reaction in liquid induced by He/O{sub 2} plasma-jet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Atsushi; Uchida, Giichiro, E-mail: uchida@jwri.osaka-u.ac.jp; Takenaka, Kosuke; Setsuhara, Yuichi [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Kawasaki, Toshiyuki [Department of Mechanical and Electrical Engineering, Nippon Bunri University, Oita, Oita 870-0397 (Japan); Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Shiratani, Masaharu [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Fukuoka 819-0395 (Japan)

    2015-07-28

    We present here analysis of oxidation reaction in liquid by a plasma-jet irradiation under various gas flow patterns such as laminar and turbulence flows. To estimate the total amount of oxidation reaction induced by reactive oxygen species (ROS) in liquid, we employ a KI-starch solution system, where the absorbance of the KI-starch solution near 600 nm behaves linear to the total amount of oxidation reaction in liquid. The laminar flow with higher gas velocity induces an increase in the ROS distribution area on the liquid surface, which results in a large amount of oxidation reaction in liquid. However, a much faster gas flow conversely results in a reduction in the total amount of oxidation reaction in liquid under the following two conditions: first condition is that the turbulence flow is triggered in a gas flow channel at a high Reynolds number of gas flow, which leads to a marked change of the spatial distribution of the ROS concentration in gas phase. Second condition is that the dimpled liquid surface is formed by strong gas flow, which prevents the ROS from being transported in radial direction along the liquid surface.

  8. Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

    International Nuclear Information System (INIS)

    Miyabe, M.; Oba, M.; Iimura, H.; Akaoka, K.; Khumaeni, A.; Kato, M.; Wakaida, I.

    2015-01-01

    The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5–6 J/cm 2 ) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis. - Highlights: • Ablated ground-state species accumulated in a thin hemispherical boundary layer • Inside the layer, a cavity containing a small density of ablated species was formed. • The hemispherical layers of atoms and ions appeared at a nearly identical location. • The measured intensity peak variation was in good agreement with a model prediction. • We ascribed the dominant process for forming the layer to a three-body recombination

  9. Impacts of bedding directions of shale gas reservoirs on hydraulically induced crack propagation

    Directory of Open Access Journals (Sweden)

    Keming Sun

    2016-03-01

    Full Text Available Shale gas reservoirs are different from conventional ones in terms of their bedding architectures, so their hydraulic fracturing rules are somewhat different. In this paper, shale hydraulic fracturing tests were carried out by using the triaxial hydraulic fracturing test system to identify the effects of natural bedding directions on the crack propagation in the process of hydraulic fracturing. Then, the fracture initiation criterion of hydraulic fracturing was prepared using the extended finite element method. On this basis, a 3D hydraulic fracturing computation model was established for shale gas reservoirs. And finally, a series of studies were performed about the effects of bedding directions on the crack propagation created by hydraulic fracturing in shale reservoirs. It is shown that the propagation rules of hydraulically induced fractures in shale gas reservoirs are jointly controlled by the in-situ stress and the bedding plane architecture and strength, with the bedding direction as the main factor controlling the crack propagation directions. If the normal tensile stress of bedding surface reaches its tensile strength after the fracturing, cracks will propagate along the bedding direction, and otherwise vertical to the minimum in-situ stress direction. With the propagating of cracks along bedding surfaces, the included angle between the bedding normal direction and the minimum in-situ stress direction increases, the fracture initiation and propagation pressures increase and the crack areas decrease. Generally, cracks propagate in the form of non-plane ellipsoids. With the injection of fracturing fluids, crack areas and total formation filtration increase and crack propagation velocity decreases. The test results agree well with the calculated crack propagation rules, which demonstrate the validity of the above-mentioned model.

  10. Gas-to-particle conversion in the atmospheric environment by radiation-induced and photochemical reactions

    International Nuclear Information System (INIS)

    Vohra, K.G.

    1975-01-01

    During the last few years a fascinating new area of research involving ionizing radiations and photochemistry in gas-to-particle conversion in the atmosphere has been developing at a rapid pace. Two problems of major interest and concern in which this is of paramount importance are: (1) radiation induced and photochemical aerosol formation in the stratosphere and, (2) role of radiations and photochemistry in smog formation. The peak in cosmic ray intensity and significant solar UV flux in the stratosphere lead to complex variety of reactions involving major and trace constituents in this region of the atmosphere, and some of these reactions are of vital importance in aerosol formation. The problem is of great current interest because the pollutant gases from industrial sources and future SST operations entering the stratosphere could increase the aerosol burden in the stratosphere and affect the solar energy input of the troposphere with consequent ecological and climatic changes. On the other hand, in the nuclear era, the atmospheric releases from reactors and processing plants could lead to changes in the cloud nucleation behaviour of the environment and possible increase in smog formation in the areas with significant levels of radiations and conventional pollutants. A review of the earlier work, current status of the problem, and conventional pollutants. A review of the earlier work, current status of the problem, and some recent results of the experiments conducted in the author's laboratory are presented. The possible mechanisms of gas-to-particle conversion in the atmosphere have been explained

  11. Experimental study of acoustic damping induced by gas-liquid scheme injectors in a combustion chamber

    International Nuclear Information System (INIS)

    Kim, Hak Soon; Sohn, Chae Hoon

    2007-01-01

    In a liquid rocket engine, acoustic damping induced by gas-liquid scheme injectors is studied experimentally for combustion stability by adopting linear acoustic test. In the previous work, it has been found that gas-liquid scheme injector can play a significant role in acoustic damping or absorption when it is tuned finely. Based on this finding, acoustic-damping characteristics of multi-injectors are intensively investigated. From the experimental data, it is found that acoustic oscillations are almost damped out by multi-injectors when they have the tuning length proposed in the previous study. The length corresponds to a half wavelength of the first longitudinal overtone mode traveling inside the injector with the acoustic frequency intended for damping in the chamber. But, new injector-coupled acoustic modes show up in the chamber with the injectors of the tuning length although the target mode is nearly damped out. And, appreciable frequency shift is always observed except for the case of the worst tuned injector. Accordingly, it is proposed that the tuning length is adjusted to have the shorter length than a half wavelength when these phenomena are considered

  12. Nuclear Spiral Shocks and Induced Gas Inflows in Weak Oval Potentials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woong-Tae [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Elmegreen, Bruce G., E-mail: wkim@astro.snu.ac.kr, E-mail: bge@us.ibm.com [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

    2017-05-20

    Nuclear spirals are ubiquitous in galaxy centers. They exist not only in strong barred galaxies but also in galaxies without noticeable bars. We use high-resolution hydrodynamic simulations to study the properties of nuclear gas spirals driven by weak bar-like and oval potentials. The amplitude of the spirals increases toward the center by a geometric effect, readily developing into shocks at small radii even for very weak potentials. The shape of the spirals and shocks depends rather sensitively on the background shear. When shear is low, the nuclear spirals are loosely wound and the shocks are almost straight, resulting in large mass inflows toward the center. When shear is high, on the other hand, the spirals are tightly wound and the shocks are oblique, forming a circumnuclear disk through which gas flows inward at a relatively lower rate. The induced mass inflow rates are enough to power black hole accretion in various types of Seyfert galaxies as well as to drive supersonic turbulence at small radii.

  13. Th17/Treg immunoregulation and implications in treatment of sulfur mustard gas-induced lung diseases.

    Science.gov (United States)

    Iman, Maryam; Rezaei, Ramazan; Azimzadeh Jamalkandi, Sadegh; Shariati, Parvin; Kheradmand, Farrah; Salimian, Jafar

    2017-12-01

    Sulfur mustard (SM) is an extremely toxic gas used in chemical warfare to cause massive lung injury and death. Victims exposed to SM gas acutely present with inhalational lung injury, but among those who survive, some develop obstructive airway diseases referred to as SM-lung syndrome. Pathophysiologically, SM-lung shares many characteristics with smoking-induced chronic obstructive pulmonary disease (COPD), including airway remodeling, goblet cell metaplasia, and obstructive ventilation defect. Some of the hallmarks of COPD pathogenesis, which include dysregulated lung inflammation, neutrophilia, recruitment of interleukin 17A (IL -17A) expressing CD4 + T cells (Th17), and the paucity of lung regulatory T cells (Tregs), have also been described in SM-lung. Areas covered: A literature search was performed using the MEDLINE, EMBASE, and Web of Science databases inclusive of all literature prior to and including May 2017. Expert commentary: Here we review some of the recent findings that suggest a role for Th17 cell-mediated inflammatory changes associated with pulmonary complications in SM-lung and suggest new therapeutic approaches that could potentially alter disease progression with immune modulating biologics that can restore the lung Th17/Treg balance.

  14. Physics-based forecasting of induced seismicity at Groningen gas field, the Netherlands

    Science.gov (United States)

    Dempsey, David; Suckale, Jenny

    2017-08-01

    Earthquakes induced by natural gas extraction from the Groningen reservoir, the Netherlands, put local communities at risk. Responsible operation of a reservoir whose gas reserves are of strategic importance to the country requires understanding of the link between extraction and earthquakes. We synthesize observations and a model for Groningen seismicity to produce forecasts for felt seismicity (M > 2.5) in the period February 2017 to 2024. Our model accounts for poroelastic earthquake triggering and rupture on the 325 largest reservoir faults, using an ensemble approach to model unknown heterogeneity and replicate earthquake statistics. We calculate probability distributions for key model parameters using a Bayesian method that incorporates the earthquake observations with a nonhomogeneous Poisson process. Our analysis indicates that the Groningen reservoir was not critically stressed prior to the start of production. Epistemic uncertainty and aleatoric uncertainty are incorporated into forecasts for three different future extraction scenarios. The largest expected earthquake was similar for all scenarios, with a 5% likelihood of exceeding M 4.0.

  15. Risks Associated with Unconventional Gas Extraction Projects. Induced Seismicity, NORM and Ecological Risks

    International Nuclear Information System (INIS)

    Rodrigo-Naharro, J.; Hurtado, A.; Eguilior, S.; Recreo, F.

    2015-01-01

    The latest technological advances in hydraulic fracturing (fracking) and horizontal drilling are globally driving the commercial extraction of unconventional resources. Although there is still no commercial exploitation of these resources within the EU, the fact that there are potential reserves in some countries, such as Spain, stimulates the need of performing preliminary studies to define the characteristics that an unconventional gas extraction project should consider. The object of these features are the safety of the project, thus minimizing the probabilities of negative environmental impacts, and especially since there is not any EU Framework Directive focusing on the regulation of the operation of such fossil fuels. A project of this nature, involving natural systems, must start from the knowledge of these systems and from an assessment of its features in order to reach the environmental safety of the operations. Moreover, the implementation of risk management systems, along with the existence of an appropriate legislation and supervision are key elements in the development of unconventional gas extraction projects that are environmentally friendly. The present report includes, among the overall risks associated with such projects, those related to: i) the induced seismicity; ii) the Naturally-Occurring Radioactive Materials (NORM); and iii) the ecology.

  16. Theory of current-induced spin polarization in an electron gas

    Science.gov (United States)

    Gorini, Cosimo; Maleki Sheikhabadi, Amin; Shen, Ka; Tokatly, Ilya V.; Vignale, Giovanni; Raimondi, Roberto

    2017-05-01

    We derive the Bloch equations for the spin dynamics of a two-dimensional electron gas in the presence of spin-orbit coupling. For the latter we consider both the intrinsic mechanisms of structure inversion asymmetry (Rashba) and bulk inversion asymmetry (Dresselhaus), and the extrinsic ones arising from the scattering from impurities. The derivation is based on the SU(2) gauge-field formulation of the Rashba-Dresselhaus spin-orbit coupling. Our main result is the identification of a spin-generation torque arising from Elliot-Yafet scattering, which opposes a similar term arising from Dyakonov-Perel relaxation. Such a torque, which to the best of our knowledge has gone unnoticed so far, is of basic nature, i.e., should be effective whenever Elliott-Yafet processes are present in a system with intrinsic spin-orbit coupling, irrespective of further specific details. The spin-generation torque contributes to the current-induced spin polarization (CISP), also known as inverse spin-galvanic or Edelstein effect. As a result, the behavior of the CISP turns out to be more complex than one would surmise from consideration of the internal Rashba-Dresselhaus fields alone. In particular, the symmetry of the current-induced spin polarization does not necessarily coincide with that of the internal Rashba-Dresselhaus field, and an out-of-plane component of the CISP is generally predicted, as observed in recent experiments. We also discuss the extension to the three-dimensional electron gas, which may be relevant for the interpretation of experiments in thin films.

  17. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  18. Rarefied gas flow in a rectangular enclosure induced by non-isothermal walls

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Manuel; Tatsios, Giorgos; Valougeorgis, Dimitris, E-mail: diva@mie.uth.gr [Department of Mechanical Engineering, University of Thessaly, 38334 Volos (Greece); Stefanov, Stefan [Institute of Mechanics, Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2014-05-15

    The flow of a rarefied gas in a rectangular enclosure due to the non-isothermal walls with no synergetic contributions from external force fields is investigated. The top and bottom walls are maintained at constant but different temperatures and along the lateral walls a linear temperature profile is assumed. Modeling is based on the direct numerical solution of the Shakhov kinetic equation and the Direct Simulation Monte Carlo (DSMC) method. Solving the problem both deterministically and stochastically allows a systematic comparison and verification of the results as well as the exploitation of the numerical advantages of each approach in the investigation of the involved flow and heat transfer phenomena. The thermally induced flow is simulated in terms of three dimensionless parameters characterizing the problem, namely, the reference Knudsen number, the temperature ratio of the bottom over the top plates, and the enclosure aspect ratio. Their effect on the flow configuration and bulk quantities is thoroughly examined. Along the side walls, the gas flows at small Knudsen numbers from cold-to-hot, while as the Knudsen number is increased the gas flows from hot-to-cold and the thermally induced flow configuration becomes more complex. These flow patterns with the hot-to-cold flow to be extended to the whole length of the non-isothermal side walls may exist even at small temperature differences and then, they are enhanced as the temperature difference between the top and bottom plates is increased. The cavity aspect ratio also influences this flow configuration and the hot-to-cold flow is becoming more dominant as the depth compared to the width of the cavity is increased. To further analyze the flow patterns a novel solution decomposition into ballistic and collision parts is introduced. This is achieved by accordingly modifying the indexing process of the typical DSMC algorithm. The contribution of each part of the solution is separately examined and a physical

  19. Liver Status Assessment by Spectrally and Time Resolved IR Detection of Drug Induced Breath Gas Changes

    Directory of Open Access Journals (Sweden)

    Tom Rubin

    2016-05-01

    Full Text Available The actual metabolic capacity of the liver is crucial for disease identification, liver therapy, and liver tumor resection. By combining induced drug metabolism and high sensitivity IR spectroscopy of exhaled air, we provide a method for quantitative liver assessment at bedside within 20 to 60 min. Fast administration of 13C-labelled methacetin induces a fast response of liver metabolism and is tracked in real-time by the increase of 13CO2 in exhaled air. The 13CO2 concentration increase in exhaled air allows the determination of the metabolic liver capacity (LiMAx-test. Fluctuations in CO2 concentration, pressure and temperature are minimized by special gas handling, and tracking of several spectrally resolved CO2 absorption bands with a quantum cascade laser. Absorption measurement of different 12CO2 and 13CO2 rotation-vibration transitions in the same time window allows for multiple referencing and reduction of systematic errors. This FLIP (Fast liver investigation package setup is being successfully used to plan operations and determine the liver status of patients.

  20. A Capital Adequacy Buffer Model

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); R.J. Powell (Robert); A.K. Singh (Abhay)

    2013-01-01

    markdownabstract__Abstract__ In this paper, we develop a new capital adequacy buffer model (CABM) which is sensitive to dynamic economic circumstances. The model, which measures additional bank capital required to compensate for fluctuating credit risk, is a novel combination of the Merton

  1. Smoothing type buffer memory device

    International Nuclear Information System (INIS)

    Podorozhnyj, D.M.; Yashin, I.V.

    1990-01-01

    The layout of the micropower 4-bit smoothing type buffer memory device allowing one to record without counting the sequence of input randomly distributed pulses in multi-channel devices with serial poll, is given. The power spent by a memory cell for one binary digit recording is not greater than 0.15 mW, the device dead time is 10 mus

  2. Direct Structural Identification of Gas Induced Gate-Opening Coupled with Commensurate Adsorption in a Microporous Metal-Organic Framework.

    Science.gov (United States)

    Banerjee, Debasis; Wang, Hao; Plonka, Anna M; Emge, Thomas J; Parise, John B; Li, Jing

    2016-08-08

    Gate-opening is a unique and interesting phenomenon commonly observed in flexible porous frameworks, where the pore characteristics and/or crystal structures change in response to external stimuli such as adding or removing guest molecules. For gate-opening that is induced by gas adsorption, the pore-opening pressure often varies for different adsorbate molecules and, thus, can be applied to selectively separate a gas mixture. The detailed understanding of this phenomenon is of fundamental importance to the design of industrially applicable gas-selective sorbents, which remains under investigated due to the lack of direct structural evidence for such systems. We report a mechanistic study of gas-induced gate-opening process of a microporous metal-organic framework, [Mn(ina)2 ] (ina=isonicotinate) associated with commensurate adsorption, by a combination of several analytical techniques including single crystal X-ray diffraction, in situ powder X-ray diffraction coupled with differential scanning calorimetry (XRD-DSC), and gas adsorption-desorption methods. Our study reveals that the pronounced and reversible gate opening/closing phenomena observed in [Mn(ina)2 ] are coupled with a structural transition that involves rotation of the organic linker molecules as a result of interaction of the framework with adsorbed gas molecules including carbon dioxide and propane. The onset pressure to open the gate correlates with the extent of such interaction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Production induced subsidence and seismicity in the Groningen gas field - can it be managed?

    Science.gov (United States)

    de Waal, J. A.; Muntendam-Bos, A. G.; Roest, J. P. A.

    2015-11-01

    Reliable prediction of the induced subsidence resulting from gas production is important for a near sea level country like the Netherlands. Without the protection of dunes, dikes and pumping, large parts of the country would be flooded. The predicted sea-level rise from global warming increases the challenge to design proper mitigation measures. Water management problems from gas production induced subsidence can be prevented if measures to counter its adverse effects are taken timely. This requires reliable subsidence predictions, which is a major challenge. Since the 1960's a number of large, multi-decade gas production projects were started in the Netherlands. Extensive, well-documented subsidence prediction and monitoring technologies were applied. Nevertheless predicted subsidence at the end of the Groningen field production period (for the centre of the bowl) went from 100 cm in 1971 to 77 cm in 1973 and then to 30 cm in 1977. In 1984 the prediction went up again to 65 cm, down to 36 cm in 1990 and then via 38 cm (1995) and 42 cm (2005) to 47 cm in 2010 and 49 cm in 2013. Such changes can have large implications for the planning of water management measures. Until 1991, when the first event was registered, production induced seismicity was not observed nor expected for the Groningen field. Thereafter the number of observed events rose from 5 to 10 per year during the 1990's to well over a hundred in 2013. The anticipated maximum likely magnitude rose from an initial value of less than 3.0 to a value of 3.3 in 1993 and then to 3.9 in 2006. The strongest tremor to date occurred near the village of Huizinge in August 2012. It had a magnitude of 3.6, caused significant damage and triggered the regulator into an independent investigation. Late 2012 it became clear that significantly larger magnitudes cannot be excluded and that values up to magnitude 5.0 cannot be ruled out. As a consequence the regulator advised early 2013 to lower Groningen gas production by as

  4. Production induced subsidence and seismicity in the Groningen gas field – can it be managed?

    Directory of Open Access Journals (Sweden)

    J. A. de Waal

    2015-11-01

    Full Text Available Reliable prediction of the induced subsidence resulting from gas production is important for a near sea level country like the Netherlands. Without the protection of dunes, dikes and pumping, large parts of the country would be flooded. The predicted sea-level rise from global warming increases the challenge to design proper mitigation measures. Water management problems from gas production induced subsidence can be prevented if measures to counter its adverse effects are taken timely. This requires reliable subsidence predictions, which is a major challenge. Since the 1960's a number of large, multi-decade gas production projects were started in the Netherlands. Extensive, well-documented subsidence prediction and monitoring technologies were applied. Nevertheless predicted subsidence at the end of the Groningen field production period (for the centre of the bowl went from 100 cm in 1971 to 77 cm in 1973 and then to 30 cm in 1977. In 1984 the prediction went up again to 65 cm, down to 36 cm in 1990 and then via 38 cm (1995 and 42 cm (2005 to 47 cm in 2010 and 49 cm in 2013. Such changes can have large implications for the planning of water management measures. Until 1991, when the first event was registered, production induced seismicity was not observed nor expected for the Groningen field. Thereafter the number of observed events rose from 5 to 10 per year during the 1990's to well over a hundred in 2013. The anticipated maximum likely magnitude rose from an initial value of less than 3.0 to a value of 3.3 in 1993 and then to 3.9 in 2006. The strongest tremor to date occurred near the village of Huizinge in August 2012. It had a magnitude of 3.6, caused significant damage and triggered the regulator into an independent investigation. Late 2012 it became clear that significantly larger magnitudes cannot be excluded and that values up to magnitude 5.0 cannot be ruled out. As a consequence the regulator advised early 2013 to lower Groningen gas

  5. High dielectric constant and energy density induced by the tunable TiO2 interfacial buffer layer in PVDF nanocomposite contained with core-shell structured TiO2@BaTiO3 nanoparticles

    Science.gov (United States)

    Hu, Penghao; Jia, Zhuye; Shen, Zhonghui; Wang, Peng; Liu, Xiaoru

    2018-05-01

    To realize application in high-capacity capacitors and portable electric devices, large energy density is eagerly desired for polymer-based nanocomposite. The core-shell structured nanofillers with inorganic buffer layer are recently supposed to be promising in improving the dielectric property of polymer nanocomposite. In this work, core-shell structured TO@BT nanoparticles with crystalline TiO2 buffer layer coated on BaTiO3 nanoparticle were fabricated via solution method and heat treatment. The thickness of the TO buffer layer can be tailored by modulating the additive amount of the titanate coupling agent in preparation process, and the apparent dielectric properties of nanocomposite are much related to the thickness of the TO layer. The relatively thin TO layer prefer to generate high polarization to increase dielectric constant while the relatively thick TO layer would rather to homogenize field to maintain breakdown strength. Simulation of electric field distribution in the interfacial region reveals the improving effect of the TO buffer layer on the dielectric properties of nanocomposite which accords with the experimental results well. The optimized nanoparticle TO@BT-2 with a mean thickness of 3-5 nm buffer layer of TO is effective in increasing both the ε and Eb in the PVDF composite film. The maximal discharged energy density of 8.78 J/cm3 with high energy efficiency above 0.6 is obtained in TO@BT-2/PVDF nanocomposite with 2.5 vol% loading close to the breakdown strength of 380 kV/mm. The present study demonstrates the approach to optimize the structure of core-shell nanoparticles by modulating buffer layer and provides a new way to further enlarge energy density in polymer nanocomposite.

  6. Multiplicity dependence of matrix-induced frequency shifts for atomic transitions of the group 12 metals in rare gas solids

    International Nuclear Information System (INIS)

    Laursen, S.L.; Cartland, H.E.

    1991-01-01

    Atomic resonances of the group 12 metal atoms, Hg, Cd, and Zn, undergo frequency shifts from the gas phase atomic line when trapped in rare gas matrices of Ar, Kr, and Xe at 12 K. As expected, the shifts are approximately linear in polarizability of the rare gas, but the slope of this line depends on whether the transition in question is 1 P 1 left-arrow 1 S 0 or 3 P 1 left-arrow 1 S 0 . Thus the matrix-induced frequency shift is dependent on the singlet or triplet nature of the excited state as well as on the matrix material. This dependence on multiplicity is discussed in terms of interactions between the excited-state atomic orbitals and the matrix. The results are compared to matrix studies of other metals and to related gas-phase work on diatomic van der Waals complexes of group 12 metals with rare gases

  7. Inhibition of inducible Nitric Oxide Synthase by a mustard gas analog in murine macrophages

    Directory of Open Access Journals (Sweden)

    Smith Milton

    2006-11-01

    Full Text Available Abstract Background 2-Chloroethyl ethyl sulphide (CEES is a sulphur vesicating agent and an analogue of the chemical warfare agent 2,2'-dichlorodiethyl sulphide, or sulphur mustard gas (HD. Both CEES and HD are alkylating agents that influence cellular thiols and are highly toxic. In a previous publication, we reported that lipopolysaccharide (LPS enhances the cytotoxicity of CEES in murine RAW264.7 macrophages. In the present investigation, we studied the influence of CEES on nitric oxide (NO production in LPS stimulated RAW264.7 cells since NO signalling affects inflammation, cell death, and wound healing. Murine macrophages stimulated with LPS produce NO almost exclusively via inducible nitric oxide synthase (iNOS activity. We suggest that the influence of CEES or HD on the cellular production of NO could play an important role in the pathophysiological responses of tissues to these toxicants. In particular, it is known that macrophage generated NO synthesised by iNOS plays a critical role in wound healing. Results We initially confirmed that in LPS stimulated RAW264.7 macrophages NO is exclusively generated by the iNOS form of nitric oxide synthase. CEES treatment inhibited the synthesis of NO (after 24 hours in viable LPS-stimulated RAW264.7 macrophages as measured by either nitrite secretion into the culture medium or the intracellular conversion of 4,5-diaminofluorescein diacetate (DAF-2DA or dichlorofluorescin diacetate (DCFH-DA. Western blots showed that CEES transiently decreased the expression of iNOS protein; however, treatment of active iNOS with CEES in vitro did not inhibit its enzymatic activity Conclusion CEES inhibits NO production in LPS stimulated macrophages by decreasing iNOS protein expression. Decreased iNOS expression is likely the result of CEES induced alteration in the nuclear factor kappa B (NF-κB signalling pathway. Since NO can act as an antioxidant, the CEES induced down-regulation of iNOS in LPS

  8. Gas-water-rock interactions induced by reservoir exploitation, CO2 sequestration, and other geological storage

    International Nuclear Information System (INIS)

    Lecourtier, J.

    2005-01-01

    Here is given a summary of the opening address of the IFP International Workshop: 'gas-water-rock interactions induced by reservoir exploitation, CO 2 sequestration, and other geological storage' (18-20 November 2003). 'This broad topic is of major interest to the exploitation of geological sites since gas-water-mineral interactions determine the physicochemical characteristics of these sites, the strategies to adopt to protect the environment, and finally, the operational costs. Modelling the phenomena is a prerequisite for the engineering of a geological storage, either for disposal efficiency or for risk assessment and environmental protection. During the various sessions, several papers focus on the great achievements that have been made in the last ten years in understanding and modelling the coupled reaction and transport processes occurring in geological systems, from borehole to reservoir scale. Remaining challenges such as the coupling of mechanical processes of deformation with chemical reactions, or the influence of microbiological environments on mineral reactions will also be discussed. A large part of the conference programme will address the problem of mitigating CO 2 emissions, one of the most important issues that our society must solve in the coming years. From both a technical and an economic point of view, CO 2 geological sequestration is the most realistic solution proposed by the experts today. The results of ongoing pilot operations conducted in Europe and in the United States are strongly encouraging, but geological storage will be developed on a large scale in the future only if it becomes possible to predict the long term behaviour of stored CO 2 underground. In order to reach this objective, numerous issues must be solved: - thermodynamics of CO 2 in brines; - mechanisms of CO 2 trapping inside the host rock; - geochemical modelling of CO 2 behaviour in various types of geological formations; - compatibility of CO 2 with oil-well cements

  9. The thermodynamic-buffer enzymes.

    Science.gov (United States)

    Stucki, J W

    1980-08-01

    Oxidative phosphorylation operates at optimal efficiency if and only if the condition of conductance matching L33/L11 = square root 1-q2 is fulfilled. In this relation L11 is the phenomenological conductance of phosphorylation, L33 the phenomenological conductance of the load, i.e. the irreversible ATP-utilizing processes in the cell, and q the degree of coupling of oxidative phosphorylation driven by respiration. Since during short time intervals L11 and q are constant whereas L33 fluctuates in the cell, oxidative phosphorylation would only rarely operate at optimal efficiency due to violation of conductance matching. This paper demonstrates that the reversible ATP-utilizing reaction catalyzed by adenylate kinase can effectively compensate deviations from conductance matching in the presence of a fluctuating L33 and hence allows oxidative phosphorylation to operate at optimal efficiency in the cell. Since the adenylate kinase reaction was found to buffer a thermodynamic potential, i.e. the phosphate potential, this finding was generalized to the concept of thermodynamic buffering. The thermodynamic buffering ability of the adenylate kinase reaction was demonstrated by experiments with incubated rat-liver mitochondria. Considerations of changes introduced in the entropy production by the adenylate kinase reaction allowed to establish the theoretical framework for thermodynamic buffering. The ability of thermodynamic buffering to compensate deviations from conductance matching in the presence of fluctuating loads was demonstrated by computer simulations. The possibility of other reversible ATP-utilizing reactions, like the ones catalyzed by creatine kinase and arginine kinase, to contribute to thermodynamic buffering is discussed. Finally, the comparison of the theoretically calculated steady-stae cytosolic adenine nucleotide concentrations with experimental data from perfused livers demonstrated that in livers from fed rats conductance matching is fulfilled on a

  10. Oil price induced gas acquisition contracts. Immune to price changes; Oelpreisindizierte Gasbezugsvertraege. Immun gegen Preisaenderungen

    Energy Technology Data Exchange (ETDEWEB)

    Verhoeven, Meike [Soptim AG, Aachen (Germany)

    2012-10-15

    The gas price continues to be linked to the oil price. Gas utilities that must buy gas in these conditions and sell it at a fixed price incur considerable financial risk. Especially with long-term buying contracts, and especially for gas from Russia, producers insist on linking to the oil price. Gas utilities, on the other hand, had to stop to sell gas at a price linked to the oil price two years ago. Utilities attempt to protect themselves, e.g. via oil swaps. Professional portfolio management is necessary to cope with the risks and the highly complex processes involved.

  11. Offsetting global warming-induced elevated greenhouse gas emissions from an arable soil by biochar application.

    Science.gov (United States)

    Bamminger, Chris; Poll, Christian; Marhan, Sven

    2018-01-01

    Global warming will likely enhance greenhouse gas (GHG) emissions from soils. Due to its slow decomposability, biochar is widely recognized as effective in long-term soil carbon (C) sequestration and in mitigation of soil GHG emissions. In a long-term soil warming experiment (+2.5 °C, since July 2008) we studied the effect of applying high-temperature Miscanthus biochar (0, 30 t/ha, since August 2013) on GHG emissions and their global warming potential (GWP) during 2 years in a temperate agroecosystem. Crop growth, physical and chemical soil properties, temperature sensitivity of soil respiration (R s ), and metabolic quotient (qCO 2 ) were investigated to yield further information about single effects of soil warming and biochar as well as on their interactions. Soil warming increased total CO 2 emissions by 28% over 2 years. The effect of warming on soil respiration did not level off as has often been observed in less intensively managed ecosystems. However, the temperature sensitivity of soil respiration was not affected by warming. Overall, biochar had no effect on most of the measured parameters, suggesting its high degradation stability and its low influence on microbial C cycling even under elevated soil temperatures. In contrast, biochar × warming interactions led to higher total N 2 O emissions, possibly due to accelerated N-cycling at elevated soil temperature and to biochar-induced changes in soil properties and environmental conditions. Methane uptake was not affected by soil warming or biochar. The incorporation of biochar-C into soil was estimated to offset warming-induced elevated GHG emissions for 25 years. Our results highlight the suitability of biochar for C sequestration in cultivated temperate agricultural soil under a future elevated temperature. However, the increased N 2 O emissions under warming limit the GHG mitigation potential of biochar. © 2017 John Wiley & Sons Ltd.

  12. Seasonal trends in reduced leaf gas exchange and ozone-induced foliar injury in three ozone sensitive woody plant species

    Energy Technology Data Exchange (ETDEWEB)

    Novak, K. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)]. E-mail: kristopher.novak@wsl.ch; Schaub, M. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Fuhrer, J. [Swiss Federal Research Station for Agroecology and Agriculture FAL, 8046 Zurich (Switzerland); Skelly, J.M. [Department of Plant Pathology, The Pennsylvania State University, University Park, PA 16802 (United States); Hug, C. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Landolt, W. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Bleuler, P. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Kraeuchi, N. [Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

    2005-07-15

    Seasonal trends in leaf gas exchange and ozone-induced visible foliar injury were investigated for three ozone sensitive woody plant species. Seedlings of Populus nigra L., Viburnum lantana L., and Fraxinus excelsior L. were grown in charcoal-filtered chambers, non-filtered chambers and open plots. Injury assessments and leaf gas exchange measurements were conducted from June to October during 2002. All species developed typical ozone-induced foliar injury. For plants exposed to non-filtered air as compared to the charcoal-filtered air, mean net photosynthesis was reduced by 25%, 21%, and 18% and mean stomatal conductance was reduced by 25%, 16%, and 8% for P. nigra, V. lantana, and F. excelsior, respectively. The timing and severity of the reductions in leaf gas exchange were species specific and corresponded to the onset of visible foliar injury. - Reductions in leaf gas exchange corresponded to the onset of ozone-induced visible foliar injury for seedlings exposed to ambient ozone exposures.

  13. Seasonal trends in reduced leaf gas exchange and ozone-induced foliar injury in three ozone sensitive woody plant species

    International Nuclear Information System (INIS)

    Novak, K.; Schaub, M.; Fuhrer, J.; Skelly, J.M.; Hug, C.; Landolt, W.; Bleuler, P.; Kraeuchi, N.

    2005-01-01

    Seasonal trends in leaf gas exchange and ozone-induced visible foliar injury were investigated for three ozone sensitive woody plant species. Seedlings of Populus nigra L., Viburnum lantana L., and Fraxinus excelsior L. were grown in charcoal-filtered chambers, non-filtered chambers and open plots. Injury assessments and leaf gas exchange measurements were conducted from June to October during 2002. All species developed typical ozone-induced foliar injury. For plants exposed to non-filtered air as compared to the charcoal-filtered air, mean net photosynthesis was reduced by 25%, 21%, and 18% and mean stomatal conductance was reduced by 25%, 16%, and 8% for P. nigra, V. lantana, and F. excelsior, respectively. The timing and severity of the reductions in leaf gas exchange were species specific and corresponded to the onset of visible foliar injury. - Reductions in leaf gas exchange corresponded to the onset of ozone-induced visible foliar injury for seedlings exposed to ambient ozone exposures

  14. Urban Runoff: Model Ordinances for Aquatic Buffers

    Science.gov (United States)

    Aquatic Buffers serve as natural boundaries between local waterways and existing development. The model and example ordinaces below provide suggested language or technical guidance designed to create the most effective stream buffer zones possible.

  15. Buffer Zone Requirements for Soil Fumigant Applications

    Science.gov (United States)

    Updated pesticide product labels require fumigant users to establish a buffer zone around treated fields to reduce risks to bystanders. Useful information includes tarp testing guidance and a buffer zone calculator.

  16. Swelling characteristics of buffer material

    International Nuclear Information System (INIS)

    Suzuki, Hideaki; Fujita, Tomoo

    1999-12-01

    After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanism, infiltration of groundwater from the surrounding rock into the EBS, generation of swelling pressure in the buffer due to water infiltration and the stress imposed by the overburden pressure. These phenomena are not all independent, but can be strongly influenced by, and coupled with, each other. Evaluating these coupled thermo-hydro-mechanical phenomena is important in order to clarify the initial transient behavior of the engineered barrier system within the near-field. This report describes the results on measurement of swelling amount and stress at boundary built up under restraint condition with water uptake. The following results are identified. (1) The swelling stress of buffer material at saturated condition tends to be independent of effects of pore water pressure and synthetic sea water, and to decrease with increasing temperature. The swelling stress can be explained by the effective dry density. (2) The strain due to swelling estimated from the results of the swelling amount of buffer material is proportional to swelling stress. (3) The swelling stress and strain under unsaturated condition increase with water uptake. (author)

  17. Reservoir creep and induced seismicity: inferences from geomechanical modeling of gas depletion in the Groningen field

    Science.gov (United States)

    van Wees, Jan-Diederik; Osinga, Sander; Van Thienen-Visser, Karin; Fokker, Peter A.

    2018-03-01

    The Groningen gas field in the Netherlands experienced an immediate reduction in seismic events in the year following a massive cut in production. This reduction is inconsistent with existing models of seismicity predictions adopting compaction strains as proxy, since reservoir creep would then result in a more gradual reduction of seismic events after a production stop. We argue that the discontinuity in seismic response relates to a physical discontinuity in stress loading rate on faults upon the arrest of pressure change. The stresses originate from a combination of the direct poroelastic effect through the pressure changes and the delayed effect of ongoing compaction after cessation of reservoir production. Both mechanisms need to be taken into account. To this end, we employed finite-element models in a workflow that couples Kelvin-Chain reservoir creep with a semi-analytical approach for the solution of slip and seismic moment from the predicted stress change. For ratios of final creep and elastic compaction up to 5, the model predicts that the cumulative seismic moment evolution after a production stop is subject to a very moderate increase, 2-10 times less than the values predicted by the alternative approaches using reservoir compaction strain as proxy. This is in agreement with the low seismicity in the central area of the Groningen field immediately after reduction in production. The geomechanical model findings support scope for mitigating induced seismicity through adjusting rates of pressure change by cutting down production.

  18. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Z.; Chin, Y.S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  19. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    International Nuclear Information System (INIS)

    Liang, Z.; Chin, Y.S.

    2014-01-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  20. Bubble-induced mixing of two horizontal liquid layers with non-uniform gas injection at the bottom

    International Nuclear Information System (INIS)

    Cheung, F.B.; Pedersen, D.R.; Leinweber, G.

    1986-01-01

    During a postulated severe core meltdown accident in an LMFBR, a large amount of sodium coolant may spill into the reactor concrete cavity. A layer of liquid products may form as a result of the sodium-concrete reactions. The liquid product layer, which is highly viscous and much heavier than sodium, separates the concrete from the sodium pool. In general, the downward transport of sodium through the liquid product layer to the unreacted concrete surface, which controls the rate of chemical erosion of the concrete, depends strongly on the agitation induced by gas evolution from the heated concrete. In this study, experiments were conducted to explore the effect of non-uniform gas injection on mixing of two horizontal mutually soluble liquid layers. The liquid in the lower layer was chosen to be more viscous and heavier than the liquid in the upper layer. To simulate the reactor accident situation, gas was injected at the bottom of the liquid-liquid system through a circular hole that covered only the center portion of the bottom surface of the lower liquid layer. The bubble-induced mixing motions were observed and the rate of mixing was measured for different hole sizes and various gas flow rates. The results of this study clearly show that the rate of gas injection is not the only parameter controlling the mixing of the liquid-liquid system. The effect of non-uniform gas injection is important at high gas flow rates. Within the present experimental conditions, the reduction in the overall mixing rate can be as large as a factor of three

  1. cGAS Senses Human Cytomegalovirus and Induces Type I Interferon Responses in Human Monocyte-Derived Cells.

    Directory of Open Access Journals (Sweden)

    Jennifer Paijo

    2016-04-01

    Full Text Available Human cytomegalovirus (HCMV infections of healthy individuals are mostly unnoticed and result in viral latency. However, HCMV can also cause devastating disease, e.g., upon reactivation in immunocompromised patients. Yet, little is known about human immune cell sensing of DNA-encoded HCMV. Recent studies indicated that during viral infection the cyclic GMP/AMP synthase (cGAS senses cytosolic DNA and catalyzes formation of the cyclic di-nucleotide cGAMP, which triggers stimulator of interferon genes (STING and thus induces antiviral type I interferon (IFN-I responses. We found that plasmacytoid dendritic cells (pDC as well as monocyte-derived DC and macrophages constitutively expressed cGAS and STING. HCMV infection further induced cGAS, whereas STING expression was only moderately affected. Although pDC expressed particularly high levels of cGAS, and the cGAS/STING axis was functional down-stream of STING, as indicated by IFN-I induction upon synthetic cGAMP treatment, pDC were not susceptible to HCMV infection and mounted IFN-I responses in a TLR9-dependent manner. Conversely, HCMV infected monocyte-derived cells synthesized abundant cGAMP levels that preceded IFN-I production and that correlated with the extent of infection. CRISPR/Cas9- or siRNA-mediated cGAS ablation in monocytic THP-1 cells and primary monocyte-derived cells, respectively, impeded induction of IFN-I responses following HCMV infection. Thus, cGAS is a key sensor of HCMV for IFN-I induction in primary human monocyte-derived DC and macrophages.

  2. Evaluation of genetic alteration induced by radon gas using the micronucleus test (Tradescantia sp. clone KU-20)

    International Nuclear Information System (INIS)

    Bruschi, Armando L.; Azevedo, Heliana de; Macacini, Jose F.; Roque, Claudio V.

    2011-01-01

    The first observations over the existence of radon gas (Rn), initially known as 'thorium emanation', were carried out between the end of 19 th and beginning of 20 th centuries. A result of uranium-238 (U 238 ) radioactive decay, radon is a tasteless, odorless and colorless gas under room temperature, with a 3.825-day half life and particle α emission in its decay, and as final product of its disintegration, the stable lead-206 isotope (Pb 206 ). Being it is the gas with the highest density known, closed and poor ventilated environments are favorable to its accumulation, with its inhalation being the highest health risk. The use of vegetal bioindicators has shown to be excellent on the monitoring of air quality and on mutagenic potential of various pollutants contained in the atmosphere. Within this context, the objective of this study was to evaluate the micronucleus test application potential utilizing the Tradescantia sp. clone KU-20, in order to evaluate genetic alterations induced by radon gas. Stems of Tradescantia sp. clone KU-20, previously immerse in Hoagland solution, were introduced in a radon detection equipment's calibration chamber (Alphaguard), containing radium salt. Afterwards, the accommodated stems were exposed to radon gas (the average radon concentration was 7.639 KBq/m3) for 24 hours. The results demonstrated an increase on micronucleus formation (39.23 + 2.143 MCN/100 tetrads) in stems exposed in relation to the negative control (18.00 + 1.396 MCN/100 tetrads). The difference between the values indicated a significant increase on micronucleus frequency in the inflorescences subjected to radon gas. The presented results demonstrated the micronucleus test application potential using Tradescantia clone KU-20 to evaluate genetic effects induced by radon gas. (author)

  3. The effect of Cr buffer layer thickness on voltage generation of thin-film thermoelectric modules

    International Nuclear Information System (INIS)

    Mizoshiri, Mizue; Mikami, Masashi; Ozaki, Kimihiro

    2013-01-01

    The effect of Cr buffer layer thickness on the open-circuit voltage generated by thin-film thermoelectric modules of Bi 0.5 Sb 1.5 Te 3 (p-type) and Bi 2 Te 2.7 Se 0.3 (n-type) materials was investigated. A Cr buffer layer, whose thickness generally needs to be optimized to improve adhesion depending on the substrate surface condition, such as roughness, was deposited between thermoelectric thin films and glass substrates. When the Cr buffer layer was 1 nm thick, the Seebeck coefficients and electrical conductivity of 1 µm thermoelectric thin films with the buffer layers were approximately equal to those of the thermoelectric films without the buffer layers. When the thickness of the Cr buffer layer was 1 µm, the same as the thermoelectric films, the Seebeck coefficients of the bilayer films were reduced by an electrical current flowing inside the Cr buffer layer and the generation of Cr 2 Te 3 . The open-circuit voltage of the thin-film thermoelectric modules decreased with an increase in the thickness of the Cr buffer layer, which was primarily induced by the electrical current flow. The reduction caused by the Cr 2 Te 3 generation was less than 10% of the total voltage generation of the modules without the Cr buffer layers. The voltage generation of thin-film thermoelectric modules could be controlled by the Cr buffer layer thickness. (paper)

  4. Buffer erosion in dilute groundwater

    International Nuclear Information System (INIS)

    Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

    2013-08-01

    One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

  5. BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

    Directory of Open Access Journals (Sweden)

    Oxana Spinu

    2015-12-01

    Full Text Available The quantitative basis of the theory of buffer properties for two-phase acid-base buffer systems and for multicomponent heterogeneous systems has been derived. The analytical equations with respect to all components for diverse multicomponent systems were deduced. It has been established, that the buffer capacities of components are mutually proportional.

  6. Doped LZO buffer layers for laminated conductors

    Science.gov (United States)

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  7. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    Science.gov (United States)

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

  8. The synthesis of a new type adsorbent for the removal of toxic gas by radiation-induced graft polymerization

    International Nuclear Information System (INIS)

    Okamoto, Jiro; Sugo, Takanobu

    1990-01-01

    A new type of adsorbent containing sulfuric acid group for the removal of ammonia gas was synthesized by radiation-induced graft polymerization of styrene onto fibrous and nonwoven type polypropylene followed by sulufonation with chlorosulfonic acid. The rate of the adsorption of ammonia gas by H-type adsorbent is independent of the ion-exchange capacity. The amount of ammonia gas adsorbed by the chemical adsorption was dependent on the ion-exchange capacity of H-type fibrous adsorbent and was kept constant value in spite of the equilibrium pressure of ammonia gas. Cu(II)- and Ni(II)-types fibrous adsorbent were prepared by the ion exchange reaction of Na-type fibrous adsorbent with metal nitrate solutions. Although, the rate of adsorption of ammonia gas by metal-type fibrous adsorbent is lower than that of H-type adsorbent, the amount of ammonia gas adsorbed increases compared to H-type adsorbent with the same ion exchange capacity. It was related to the highest coordination number of metal ion. The ratio of the number of ammonia molecules adsorbed chemically and the number of metal ion adsorbed in fibrous adsorbent was 4 for Cu-type and 6 for Ni-type fibrous adsorbent, respectively. (author)

  9. Effect of molecular weight and density of ambient gas on shock wave in laser-induced surface nanostructuring

    International Nuclear Information System (INIS)

    Guo Liying; Wang Xinwei

    2009-01-01

    This paper presents the results of molecular dynamics studies about the shock wave during laser-induced surface nanostructuring. A quasi-three dimensional model is constructed to study systems consisting of over 2 million atoms. Detailed studies are carried out about the shock wave front and Mach number, evolution of plume and ambient gas interaction zone, and energy exchange between the ambient gas and plume. Under an ambience of lower pressure or lighter molecular mass, the plume affects a larger area while the strength of the shock wave front is weaker. With the same ambient pressure, the ablated material features the same kinetic energy at the late stage regardless of the molecular weight of the ambient gas. The same conclusion holds for the energy increase of the ambient gas as well. When the ambient pressure is reduced, more kinetic energy is carried out by the ablated material while less energy is transferred to the ambient gas. It is observed that heavier ambient gas could bounce back the ablated material to the target surface.

  10. Simulation of HTM processes in buffer-rock barriers based on the French HLW disposal concept

    International Nuclear Information System (INIS)

    Li, Xiaoshuo; Roehlig, Klaus-Juergen; Zhang, Chunliang

    2012-01-01

    Document available in extended abstract form only. The main objectives of this paper are to gain experience with modelling and analysis of HTM processes in clay rock and bentonite buffer surrounding heat-generating radioactive waste. The French concept for HLW disposal in drifts with backfilled bentonite buffer considered in numerical calculations which are carried out by using the computer code CODE-BRIGHT developed by the Technical University of Catalonia in Barcelona. The French repository designed by ANDRA is located in the middle of the Callovo-Oxfordian argillaceous formation (COX) of 250 m thickness at a depth of 500 to 630 m below the surface. The French concept has been simplified at this simulation work. A drift is considered to be excavated at a depth of 500 m below the surface. It has a diameter of 2.2 m and a length of 20 m. A large volume of the rock mass around the drift is taken into account by an axisymmetric model of 100 m radius and 100 m length. In fact, this model represents a cylindrical rock-buffer-system with the central axis of the containers, as shown in Figure 1. Some points are selected in the buffer and the rock along the radial line (dash yellow line) in the middle of the drift for recording HTM parameters with time. The display and analysis of the results at this paper are chiefly along this line. The simulation work has been divided to two time steps. At the first step, the drift excavation and ventilation is simulated by reducing the stress normal to the drift wall down to zero and circulating gas along the drift wall with relative humidity of 85 %. Following the drift excavation and ventilation, the HLW containers and the bentonite are emplaced in the drift as the second step of the simulation. This is simulated by simultaneously applying the initial conditions of the buffer and the decayed heat emitting from the waste containers as thermal boundary conditions. Two materials (Clay rock and bentonite buffer) are taken into account

  11. Two dimensional laser induced fluorescence in the gas phase: a spectroscopic tool for studying molecular spectroscopy and dynamics

    Science.gov (United States)

    Gascooke, Jason R.; Lawrance, Warren D.

    2017-11-01

    Two dimensional laser induced fluorescence (2D-LIF) extends the usual laser induced fluorescence technique by adding a second dimension, the wavelength at which excited states emit, thereby significantly enhancing the information that can be extracted. It allows overlapping absorption features, whether they arise from within the same molecule or from different molecules in a mixture, to be associated with their appropriate "parent" state and/or molecule. While the first gas phase version of the technique was published a decade ago, the technique is in its infancy, having been exploited by only a few groups to date. However, its potential in gas phase spectroscopy and dynamics is significant. In this article we provide an overview of the technique and illustrate its potential with examples, with a focus on those utilising high resolution in the dispersed fluorescence dimension.

  12. Quantitative study of the ionization-induced refraction of picosecond laser pulses in gas-jet targets

    International Nuclear Information System (INIS)

    Mackinnon, A.J.; Borghesi, M.; Iwase, A.; Jones, M.W.; Pert, G.J.; Rae, S.; Burnett, K.; Willi, O.

    1996-01-01

    A quantitative study of refractive whole beam defocusing and small scale breakup induced by optical ionization of subpicosecond and picosecond, 0.25 and 1 μm, laser pulses in gas-jet targets at densities above 1x10 19 cm -3 has been carried out. A significant reduction of the incident laser intensity was observed due to refraction from ionization-induced density gradients. The level of refraction measured with optical probing correlated well with the fraction of energy transmitted through the plasma. The numerical and analytical models were found to agree well with experimental observations. copyright 1996 The American Physical Society

  13. Improving Water Quality With Conservation Buffers

    Science.gov (United States)

    Lowrance, R.; Dabney, S.; Schultz, R.

    2003-12-01

    Conservation buffer technologies are new approaches that need wider application. In-field buffer practices work best when used in combination with other buffer types and other conservation practices. Vegetative barriers may be used in combination with edge-of-field buffers to protect and improve their function and longevity by dispersing runoff and encouraging sediment deposition upslope of the buffer. It's important to understand how buffers can be managed to help reduce nutrient transport potential for high loading of nutrients from manure land application sites, A restored riparian wetland buffer retained or removed at least 59 percent of the nitrogen and 66 percent of the phosphorus that entered from an adjacent manure land application site. The Bear Creek National Restoration Demonstration Watershed project in Iowa has been the site of riparian forest buffers and filter strips creation; constructed wetlands to capture tile flow; stream-bank bioengineering; in-stream structures; and controlling livestock grazing. We need field studies that test various widths of buffers of different plant community compositions for their efficacy in trapping surface runoff, reducing nonpoint source pollutants in subsurface waters, and enhancing the aquatic ecosystem. Research is needed to evaluate the impact of different riparian grazing strategies on channel morphology, water quality, and the fate of livestock-associated pathogens and antibiotics. Integrating riparian buffers and other conservation buffers into these models is a key objective in future model development.

  14. Buffered Communication Analysis in Distributed Multiparty Sessions

    Science.gov (United States)

    Deniélou, Pierre-Malo; Yoshida, Nobuko

    Many communication-centred systems today rely on asynchronous messaging among distributed peers to make efficient use of parallel execution and resource access. With such asynchrony, the communication buffers can happen to grow inconsiderately over time. This paper proposes a static verification methodology based on multiparty session types which can efficiently compute the upper bounds on buffer sizes. Our analysis relies on a uniform causality audit of the entire collaboration pattern - an examination that is not always possible from each end-point type. We extend this method to design algorithms that allocate communication channels in order to optimise the memory requirements of session executions. From these analyses, we propose two refinements methods which respect buffer bounds: a global protocol refinement that automatically inserts confirmation messages to guarantee stipulated buffer sizes and a local protocol refinement to optimise asynchronous messaging without buffer overflow. Finally our work is applied to overcome a buffer overflow problem of the multi-buffering algorithm.

  15. Geomechanical response of permafrost-associated hydrate deposits to depressurization-induced gas production

    Science.gov (United States)

    Rutqvist, J.; Moridis, G.J.; Grover, T.; Collett, T.

    2009-01-01

    In this simulation study, we analyzed the geomechanical response during depressurization production from two known hydrate-bearing permafrost deposits: the Mallik (Northwest Territories, Canada) deposit and Mount Elbert (Alaska, USA) deposit. Gas was produced from these deposits at constant pressure using horizontal wells placed at the top of a hydrate layer (HL), located at a depth of about 900??m at the Mallik site and 600??m at the Mount Elbert site. The simulation results show that general thermodynamic and geomechanical responses are similar for the two sites, but with substantially higher production and more intensive geomechanical responses at the deeper Mallik deposit. The depressurization-induced dissociation begins at the well bore and then spreads laterally, mainly along the top of the HL. The depressurization results in an increased shear stress within the body of the receding hydrate and causes a vertical compaction of the reservoir. However, its effects are partially mitigated by the relatively stiff permafrost overburden, and compaction of the HL is limited to less than 0.4%. The increased shear stress may lead to shear failure in the hydrate-free zone bounded by the HL overburden and the downward-receding upper dissociation interface. This zone undergoes complete hydrate dissociation, and the cohesive strength of the sediment is low. We determined that the likelihood of shear failure depends on the initial stress state as well as on the geomechanical properties of the reservoir. The Poisson's ratio of the hydrate-bearing formation is a particularly important parameter that determines whether the evolution of the reservoir stresses will increase or decrease the likelihood of shear failure.

  16. Heme Attenuation Ameliorates Irritant Gas Inhalation-Induced Acute Lung Injury

    Science.gov (United States)

    Aggarwal, Saurabh; Lam, Adam; Bolisetty, Subhashini; Carlisle, Matthew A.; Traylor, Amie; Agarwal, Anupam

    2016-01-01

    Abstract Aims: Exposure to irritant gases, such as bromine (Br2), poses an environmental and occupational hazard that results in severe lung and systemic injury. However, the mechanism(s) of Br2 toxicity and the therapeutic responses required to mitigate lung damage are not known. Previously, it was demonstrated that Br2 upregulates the heme degrading enzyme, heme oxygenase-1 (HO-1). Since heme is a major inducer of HO-1, we determined whether an increase in heme and heme-dependent oxidative injury underlies the pathogenesis of Br2 toxicity. Results: C57BL/6 mice were exposed to Br2 gas (600 ppm, 30 min) and returned to room air. Thirty minutes postexposure, mice were injected intraperitoneally with a single dose of the heme scavenging protein, hemopexin (Hx) (3 μg/gm body weight), or saline. Twenty-four hours postexposure, saline-treated mice had elevated total heme in bronchoalveolar lavage fluid (BALF) and plasma and acute lung injury (ALI) culminating in 80% mortality after 10 days. Hx treatment significantly lowered heme, decreased evidence of ALI (lower protein and inflammatory cells in BALF, lower lung wet-to-dry weight ratios, and decreased airway hyperreactivity to methacholine), and reduced mortality. In addition, Br2 caused more severe ALI and mortality in mice with HO-1 gene deletion (HO-1−/−) compared to wild-type controls, while transgenic mice overexpressing the human HO-1 gene (hHO-1) showed significant protection. Innovation: This is the first study delineating the role of heme in ALI caused by Br2. Conclusion: The data suggest that attenuating heme may prove to be a useful adjuvant therapy to treat patients with ALI. Antioxid. Redox Signal. 24, 99–112. PMID:26376667

  17. Structure and UV-induced photochemistry of 2-furaldehyde dimethylhydrazone isolated in rare gas matrices

    Science.gov (United States)

    Araujo-Andrade, C.; Giuliano, B. M.; Gómez-Zavaglia, A.; Fausto, R.

    2012-11-01

    In this work, a combined matrix isolation FTIR and theoretical DFT(B3LYP)/6-311++G(d,p) study of 2-furaldehyde dimethylhydrazone (2FDH) was performed. According to calculations, two E and two Z conformers exist, the E forms having considerably lower energy than the Z forms. The absence of relevant sterical hindrance between the two substituents around the Cdbnd N bond (dimethylamino and 2-furyl) in the E structures and an extended π-p electron delocalization in the hydrazone moiety determines the higher stability of these species relatively to the Z structures. In the lowest energy form (E-AG) the O-C-Cdbnd N and Cdbnd N-N-Lp (Lp = lone electron pair of amine nitrogen atom) dihedral angles are predicted by the calculations to be -177.2° and 93.7°, respectively. The weak (Ndbnd C)-H⋯O hydrogen bond type interaction (H⋯O distance: 252.2 pm) in form E-AG, together with the absence in this form of the destabilizing interaction between the lone electron pairs of the oxygen and nitrogen atoms existing in E-SG, explains its lower energy in comparison with this latter form. Both E-AG and E-SG conformers could be trapped from room temperature gas phase in low temperature argon and xenon matrices. The high E-SG → E-AG energy barrier (>25 kJ mol-1) explains that, upon increasing the temperature of the matrices no conformational isomerization could be observed. After irradiation of 2FDH with UV-light at λ > 328 and λ > 234 nm, two different photochemistries were observed. Irradiation at lower energy (λ > 328 nm) induced the E-AG → E-SG isomerization. Further irradiation at higher energy (λ > 234 nm) led to a quick consumption of 2FDH and production of furan and dimethylisocyanide.

  18. Heme Attenuation Ameliorates Irritant Gas Inhalation-Induced Acute Lung Injury.

    Science.gov (United States)

    Aggarwal, Saurabh; Lam, Adam; Bolisetty, Subhashini; Carlisle, Matthew A; Traylor, Amie; Agarwal, Anupam; Matalon, Sadis

    2016-01-10

    Exposure to irritant gases, such as bromine (Br2), poses an environmental and occupational hazard that results in severe lung and systemic injury. However, the mechanism(s) of Br2 toxicity and the therapeutic responses required to mitigate lung damage are not known. Previously, it was demonstrated that Br2 upregulates the heme degrading enzyme, heme oxygenase-1 (HO-1). Since heme is a major inducer of HO-1, we determined whether an increase in heme and heme-dependent oxidative injury underlies the pathogenesis of Br2 toxicity. C57BL/6 mice were exposed to Br2 gas (600 ppm, 30 min) and returned to room air. Thirty minutes postexposure, mice were injected intraperitoneally with a single dose of the heme scavenging protein, hemopexin (Hx) (3 μg/gm body weight), or saline. Twenty-four hours postexposure, saline-treated mice had elevated total heme in bronchoalveolar lavage fluid (BALF) and plasma and acute lung injury (ALI) culminating in 80% mortality after 10 days. Hx treatment significantly lowered heme, decreased evidence of ALI (lower protein and inflammatory cells in BALF, lower lung wet-to-dry weight ratios, and decreased airway hyperreactivity to methacholine), and reduced mortality. In addition, Br2 caused more severe ALI and mortality in mice with HO-1 gene deletion (HO-1-/-) compared to wild-type controls, while transgenic mice overexpressing the human HO-1 gene (hHO-1) showed significant protection. This is the first study delineating the role of heme in ALI caused by Br2. The data suggest that attenuating heme may prove to be a useful adjuvant therapy to treat patients with ALI.

  19. Bubble-induced mixing of two horizontal liquid layers with non-uniform gas injection at the bottom

    International Nuclear Information System (INIS)

    Cheung, F.B.; Leinweber, G.; Pedersen, D.R.

    1984-01-01

    During a postulated severe core meltdown accident in an LMFBR, a large amount of sodium coolant may spill into the reactor concrete cavity. A layer of liquid products may form as a result of the sodium-concrete reactions. The liquid product layer, which is highly viscous and much heavier than sodium, separates the concrete from the sodium pool. In general, the downward transport of sodium through the liquid product layer to the unreacted concrete surface, which controls the rate of chemical erosion of the concrete, depends strongly on the agitation induced by gas evolution from the heated concrete. In this study, experiments were conducted to explore the effect of non-uniform gas injection on mixing of two horizontal mutually soluble liquid layers. The liquid in the lower layer was chosen to be more viscous and heavier than the liquid in the upper layer. To simulate the reactor accident situation, gas was injected at the bottom of the liquid-liquid system through a circular hole that covered only the center portion of the bottom surface of the lower liquid layer. The bubble-induced mixing motions were observed and the rate of mixing was measured for different hole sizes and for various gas flow rates

  20. A THEORETICAL DISCUSSION OF THE ECONOMIC EFFECTS OF BUFFER STOCKS AND BUFFER FUNDS

    OpenAIRE

    Simmons, Phil

    1988-01-01

    It has been established that the absence of risk markets justifies market intervention in principle. The form of intervention that has been discussed most widely in the literature is the buffer stock. This paper points out that other forms of intervention, specifically buffer funds, are likely to perform better. The analysis shows that buffer funds are likely to outperform buffer stocks because they address market failure more directly. A sub-theme developed in this paper is that since buffer...

  1. Shield gas induced cracks during nanosecond-pulsed laser irradiation of Zr-based metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hu; Noguchi, Jun; Yan, Jiwang [Keio University, Department of Mechanical Engineering, Faculty of Science and Technology, Yokohama (Japan)

    2016-10-15

    Laser processing techniques have been given increasing attentions in the field of metallic glasses (MGs). In this work, effects of two kinds of shield gases, nitrogen and argon, on nanosecond-pulsed laser irradiation of Zr-based MG were comparatively investigated. Results showed that compared to argon gas, nitrogen gas remarkably promoted the formation of cracks during laser irradiation. Furthermore, crack formation in nitrogen gas was enhanced by increasing the peak laser power intensity or decreasing the laser scanning speed. X-ray diffraction and micro-Raman spectroscopy indicated that the reason for enhanced cracks in nitrogen gas was the formation of ZrN. (orig.)

  2. Shield gas induced cracks during nanosecond-pulsed laser irradiation of Zr-based metallic glass

    Science.gov (United States)

    Huang, Hu; Noguchi, Jun; Yan, Jiwang

    2016-10-01

    Laser processing techniques have been given increasing attentions in the field of metallic glasses (MGs). In this work, effects of two kinds of shield gases, nitrogen and argon, on nanosecond-pulsed laser irradiation of Zr-based MG were comparatively investigated. Results showed that compared to argon gas, nitrogen gas remarkably promoted the formation of cracks during laser irradiation. Furthermore, crack formation in nitrogen gas was enhanced by increasing the peak laser power intensity or decreasing the laser scanning speed. X-ray diffraction and micro-Raman spectroscopy indicated that the reason for enhanced cracks in nitrogen gas was the formation of ZrN.

  3. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  4. The effect of radiolytically induced gas pressure on the CO2/CO/graphite system

    International Nuclear Information System (INIS)

    Curtis, A.R.; Faircloth, R.L.; Norwood, K.S.

    1980-03-01

    When radiolysed, carbon dioxide corrodes graphite to produce carbon monoxide, which can blow gas out of the graphite pores. This memorandum demonstrates how to calculate this effect, both analytically and numerically with FACSIMILE, and shows how it depends on dose rate, gas composition, specimen size and graphite diffusivity, for cylindrical geometry. The effect is very small for all cases of interest. (author)

  5. Morphological response to a North Sea bed depression induced by gas mining

    NARCIS (Netherlands)

    Fluit, C.C.J.M.; Hulscher, Suzanne J.M.H.

    2002-01-01

    Gas mining leads to saucer-like surface depressions. In the North Sea, gas is currently mined at several offshore locations. The associated bed depression has a similar spatial extent as offshore tidal sandbanks, which are large-scale bed patterns covering a significant part of the North Sea bottom.

  6. Some effects of gas-induced fluidization in dry granular media

    Energy Technology Data Exchange (ETDEWEB)

    Nermoen, Anders

    2010-06-15

    The main body of this thesis consists of three papers in which aspects of fluid induced deformation in granular materials are studied. Insight from experiments, dimensional analysis, numerical modeling and analytic predictions are combined to interpret observations various aspects of piercement structures in the geological record. A fourth paper is included showing how analogue modeling has been used to understand a geological processes. Paper 1 presents experimental work on the segregation pattern forming in partially fluidized, bi-modal sized granular mixtures. The experiments are performed on a vertically oriented Hele-Shaw cell (HS-cell), the narrow box between two parallel glass plates, filled with glass beads. Gas flow is imparted through the bottom of the bed causing fluidization when the system is driven at velocities exceeding a critical limit. The co-existence of fluidized and static zones is termed partial fluidization and occurs when the imposed gas flux is insufficient to fluidize the whole system. Within the fluidized zones, the particles re-organize and the large particles sediment down while the small particles remains fluidized. The re-organization is caused by differences in the ratio of the weight to the viscous drag. A pipe-like pattern develops due to a feedback mechanism in which the flow is focused through domains dominated by large particles. The focusing of the flow localizes the fluidization, which in turn enables the sedimentation of the large grains. Paper 2 presents an experimental and analytical study of the critical conditions for fluidization of a dry granular material. Based on the experiments, we find that the critical velocity of fluidization scales almost linear with the ratio of the filling height to the inlet width. An analytic model for the pressure field is obtained by solving the Laplace equation for the velocity boundary conditions given by the geometry of the experimental setup. By integrating the vertical component of the

  7. Characteristics study of bentonite as candidate of buffer materials for radioactive waste disposal system

    International Nuclear Information System (INIS)

    Suryantoro; Arimuladi, S.P.; Sastrowardoyo, P.B.

    1998-01-01

    Literature studies on bentonite characteristic of, as candidate for radioactive waste disposal system, have been conducted. Several information have been obtained from references, which would be contributed on performance assessment of engineered barrier. The functions bentonite includes the buffering of chemical and physical behavior, i.e. swelling property, self sealing, hydraulic conductivities and gas permeability. This paper also presented long-term stability of bentonite in natural condition related to the illitisazation, which could change its buffering capacities. These information, showed that bentonite was satisfied to be used for candidate of buffer materials in radioactive waste disposal system. (author)

  8. Vitamin K2 regression aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats.

    Science.gov (United States)

    Jiang, Xiaoyu; Tao, Huiren; Qiu, Cuiting; Ma, Xiaolei; Li, Shan; Guo, Xian; Lv, Anlin; Li, Huan

    2016-09-05

    The aim of this study was to investigate the effect of vitamin K2 on aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats. A calcification model was established by administering 3mg/g warfarin to rats. Rats were divided into 9 groups: control group (0W, 4W, 6W and 12W groups), 4W calcification group, 6W calcification group, 12W calcification group, 6W calcification+6W normal group and 6W calcification+6W vitamin K2 group. Alizarin red S staining measured aortic calcium depositions; alkaline phosphatase activity in serum was measured by a kit; apoptosis was evaluated by TUNEL assay; protein expression levels of Gas6, Axl, phosphorylated Akt (p-Akt), and Bcl-2 were determined by western blotting. The calcium content, calcium depositions, ALP activity and apoptosis were significantly higher in the calcification groups than control group. Gas6, Axl, p-Akt and Bcl-2 expression was lower in the calcification group than control group. 100μg/g vitamin K2 treatment decreased calcium depositions, ALP activity and apoptosis significantly, but increased Gas6, Axl, p-Akt and Bcl-2 expression. 100μg/g vitamin K2 reversed 44% calcification. Pearson correlation analysis showed a positive correlation between formation calcification and apoptosis (R(2)=0.8853, PK2 can inhibit warfarin-induced aortic calcification and apoptosis. The regression of aortic calcification by vitamin K2 involved the Gas6/Axl axis. This data may provide a theoretical basis for future clinical treatments for aortic calcification. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Reaction between laser ablation plume and ambient gas studied by laser-induced fluorescence imaging spectroscopy

    International Nuclear Information System (INIS)

    Sasaki, K; Watarai, H

    2007-01-01

    We visualized the density distributions of C 2 (plume), NO (ambient gas), and CN (reaction product) when a graphite target was ablated by irradiating YAG laser pulses at wavelengths of 1064 and 355 nm in ambient gas mixture of NO and He. It has been shown by the density distributions of C 2 and NO that the expansion of the plume removes the ambient gas and the plume and the ambient gas locate exclusively in both the cases at 1064 and 355 nm. A high CN density was observed at the interface between the plume and the ambient gas at 1064 nm, which is reasonable since chemical reactions between the plume and the ambient gas may occur only at their interface. On the other hand, in the case at 355 nm, we observed considerable CN inside the plume, indicating that the chemical reaction processes in the laser ablation at 355 nm is different from that expected from the density distributions of the plume and the ambient gas

  10. Buffer-induced swelling and vesicle budding in binary lipid mixtures of dioleoylphosphatidylcholine:dioleoylphosphatidylethanolamine and dioleoylphosphatidylcholine:lysophosphatidylcholine using small-angle X-ray scattering and ³¹P static NMR.

    Science.gov (United States)

    Barriga, Hanna M G; Bazin, Richard; Templer, Richard H; Law, Robert V; Ces, Oscar

    2015-03-17

    A large variety of data exists on lipid phase behavior; however, it is mostly in nonbuffered systems over nonbiological temperature ranges. We present biophysical data on lipid mixtures of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE), and lysophosphatidylcholine (LysoPC) examining their behaviors in excess water and buffer systems over the temperature range 4-34 °C. These mixtures are commonly used to investigate the effects of spontaneous curvature on integral membrane proteins. Using small-angle X-ray scattering (SAXS) and (31)P NMR, we observed lamellar and vesicle phases, with the buffer causing an increase in the layer spacing. Increasing amounts of DOPE in a DOPC bilayer decreased the layer spacing of the mesophase, while the opposite trend was observed for increasing amounts of LysoPC. (31)P static NMR was used to analyze the DOPC:LysoPC samples to investigate the vesicle sizes present, with evidence of vesicle budding observed at LysoPC concentrations above 30 mol %. NMR line shapes were fitted using an adapted program accounting for the distortion of the lipids within the magnetic field. The distortion of the vesicle, because of magnetic susceptibility, varied with LysoPC content, and a discontinuity was found in both the water and buffer samples. Generally, the distortion increased with LysoPC content; however, at a ratio of DOPC:LysoPC 60:40, the sample showed a level of distortion of the vesicle similar to that of pure DOPC. This implies an increased flexibility in the membrane at this point. Commonly, the assumption is that for increasing LysoPC concentration there is a reduction in membrane tension, implying that estimations of membrane tension based on spontaneous curvature assumptions may not be accurate.

  11. Production of noble gas isotopes by proton-induced reactions on bismuth

    International Nuclear Information System (INIS)

    Leya, I.; David, J.-C.; Leray, S.; Wieler, R.; Michel, R.

    2008-01-01

    We measured integral thin target cross sections for the proton-induced production of He-, Ne-, Ar-, Kr- and Xe-isotopes from bismuth (Bi) from the respective reaction thresholds up to 2.6 GeV. Here we present 275 cross sections for 23 nuclear reactions. The production of noble gas isotopes from Bi is of special importance for design studies of accelerator driven systems (EA/ADS) and nuclear spallation sources. For experiments with proton energies above 200 MeV the mini-stack approach was used instead of the stacked-foil technique in order to minimise the influences of secondary particles on the residual nuclide production. Comparing the cross sections for Bi to the data published recently for Pb indicates that for 4 He the cross sections for Bi below 200 MeV are up to a factor of 2-3 higher than the Pb data, which can be explained by the production of α-decaying Po-isotopes from Bi but not from Pb. Some of the cross sections for the production of 21 Ne from Bi are affected by recoil effects from neighboured Al-foils, which compromises a study of a possible lowering of the effective Coulomb-barrier. The differences in the excitation functions between Pb and Bi for Kr- and Xe-isotopes can be explained by energy-dependent higher fission cross sections for Bi compared to Pb. The experimental data are compared to results from the theoretical nuclear model codes INCL4/ABLA and TALYS. The INCL4/ABLA system describes the cross sections for the production of 4 He-, Kr- and Xe-isotopes reasonably well, i.e. mostly within a factor of a few. In contrast, the model completely fails describing 21 Ne, 22 Ne, 36 Ar and 38 Ar, which are produced via spallation and/or multifragmentation. The TALYS code is only able to accurately predict reaction thresholds. The absolute values are either significantly over- or underestimated. Consequently, the comparison of measured and modelled thin target cross sections clearly indicates that experimental data are still needed because the

  12. Spin polarization of a magnetic electron gas induced by a van Vleck ion

    International Nuclear Information System (INIS)

    Palermo, L.; Silva, X.A. do

    1978-11-01

    The mutual polarization of a magnetic electron gas and a van Vleck ion, interacting via exchange, are theoretically investigated using the double-time Green function method. A pair of equations describing the dynamics of the electron gas and the ion are conveniently decoupled and an analytic expression for the electron gas polarization, which depends on the square of the exchange parameter, is obtained. Besides a RKKY-like term, a new term associated to the process of formation of the magnetic moment of the ion appears [pt

  13. Melatonin: Buffering the Immune System

    Directory of Open Access Journals (Sweden)

    Juan M. Guerrero

    2013-04-01

    Full Text Available Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

  14. Melatonin: Buffering the Immune System

    Science.gov (United States)

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed. PMID:23609496

  15. Modelling of buffer material behaviour

    International Nuclear Information System (INIS)

    Boergesson, L.

    1988-12-01

    Some material models of smectite rich buffer material suited for nuclear waste isolation are accounted for in the report. The application of these models in finite element calculations of some scenarios and performance are also shown. The rock shear scenario has been closely studied with comparisons between calculated and measured results. Sensitivity analyses of the effect of changing the density of the clay and the rate of shear have been performed as well as one calculation using a hollow steel cylinder. Material models and finite element calculations of canister settlement, thermomechanical effects and swelling are also accounted for. The report shows the present state of the work to establish material models and calculation tools which can be used at the final design of the repository. (31 illustrations)

  16. Room temperature ferromagnetism and CH{sub 4} gas sensing of titanium oxynitride induced by milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Bolokang, Amogelang S., E-mail: Sylvester.Bolokang@transnet.net [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria, 0001 (South Africa); Transnet Engineering, Product Development, Private Bag X 528, Kilnerpark, 0127 (South Africa); Tshabalala, Zamaswazi P. [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria, 0001 (South Africa); Malgas, Gerald F. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville, 7535 (South Africa); Kortidis, Ioannis [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria, 0001 (South Africa); West Virginia University, Department of Mechanical & Aerospace Engineering, Evansdale Campus, Morgantown, WV, 26506 (United States); Swart, Hendrik C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA9300 (South Africa); Motaung, David E., E-mail: dmotaung@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria, 0001 (South Africa)

    2017-06-01

    We report on the room temperature ferromagnetism and CH{sub 4} gas sensing of titanium oxynitride prepared by milling and annealing at 1100 °C in a nitrogen gas environment. Structural analyses revealed a metastable orthorhombic TiO{sub 2} phase after milling for 120 h. The 120 h milled TiO{sub 2} particles and subsequently annealed in nitrogen gas at 1100 °C showed the formation of titanium oxynitride (TiO{sub x}N{sub y}) with a tetragonal crystal structure. An FCC metastable TiO{sub x}N{sub y} phase was also observed with a lattice parameter a = 4.235 Å. The vibrating sample magnetometer and electron paramagnetic analyses showed that the milled and TiO{sub x}N{sub y} samples possess room temperature ferromagnetism. Gas sensing measurements were carried out toward CH{sub 4} and H{sub 2} gases. The TiO{sub x}N{sub y} nanostructures demonstrated higher sensing response and selectivity to CH{sub 4} gas at room temperature. The enhanced response of 1010 and sensitivity of 50.12 ppm{sup -1} at a concentration of 20 ppm CH{sub 4} are associated with higher surface area, pore diameter and surface defects such as oxygen vacancies and Ti{sup 3+}, as evidenced from the Brunauer–Emmet–Teller, photoluminescence, electron paramagnetic resonance and x-ray photoelectron analyses. - Highlights: • Ball milled of TiO{sub 2} structure revealed metastable orthorhombic phase. • Upon nitridation tetragonal and FCC TiO{sub x}N{sub y} crystal structures were induced. • The magnetic properties of TiO{sub 2} nanoparticles was transformed by milling. • TiO{sub x}N{sub y} sensing response for CH{sub 4} gas at room temperature was high.

  17. Signature-based store checking buffer

    Science.gov (United States)

    Sridharan, Vilas; Gurumurthi, Sudhanva

    2015-06-02

    A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.

  18. Laser-induced carbon plasma emission spectroscopic measurements on solid targets and in gas-phase optical breakdown

    International Nuclear Information System (INIS)

    Nemes, Laszlo; Keszler, Anna M.; Hornkohl, James O.; Parigger, Christian

    2005-01-01

    We report measurements of time- and spatially averaged spontaneous-emission spectra following laser-induced breakdown on a solid graphite/ambient gas interface and on solid graphite in vacuum, and also emission spectra from gas-phase optical breakdown in allene C3H4 and helium, and in CO2 and helium mixtures. These emission spectra were dominated by CII (singly ionized carbon), CIII (doubly ionized carbon), hydrogen Balmer beta (H b eta), and Swan C2 band features. Using the local thermodynamic equilibrium and thin plasma assumptions, we derived electron number density and electron temperature estimates. The former was in the 1016 cm -3 range, while the latter was found to be near 20000 K. In addition, the vibration-rotation temperature of the Swan bands of the C2 radical was determined to be between 4500 and 7000 K, using an exact theoretical model for simulating diatomic emission spectra. This temperature range is probably caused by the spatial inhomogeneity of the laser-induced plasma plume. Differences are pointed out in the role of ambient CO2 in a solid graphite target and in gas-phase breakdown plasma

  19. Structural transformation and enhanced gas sensing characteristics of TiO2 nanostructures induced by annealing

    Science.gov (United States)

    Tshabalala, Zamaswazi P.; Motaung, David E.; Swart, Hendrik C.

    2018-04-01

    The improved sensitivity and selectivity, and admirable stability are fundamental features required for the current age gas sensing devices to appease future humanity and environmental requirements. Therefore, herein, we report on the room temperature gas sensing behaviour of TiO2 nanotubes with significance response and sensitivity towards 60 ppm NO2 gas. Improved sensitivity of 29.44 ppm-1 and admirable selectivity towards NO2, among other gases ensuring adequate safety in monitoring NO2 in automobile and food industries. The improved sensitivity of TiO2 nanotubes was attributed to larger surface area provided by the hollow nanotubes resulting to improved gas adsorption and the relatively high concentration of oxygen vacancies.

  20. SODR Memory Control Buffer Control ASIC

    Science.gov (United States)

    Hodson, Robert F.

    1994-01-01

    The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

  1. Towards optical spectroscopy of the element nobelium (Z = 102) in a buffer gas cell. First on-line experiments on {sup 155}Yb at the velocity filter SHIP with a novel ion collection and atom re-evaporation method of high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Backe, H.; Kunz, P.; Lauth, W.; Dretzke, A.; Horn, R.; Kolb, T. [Mainz Univ., Institut fur Kernphysik (Germany); Laatiaoui, M.; Sewtz, M. [Munchen Ludwig-Maximilians-Univ., Dept. fur Physik, Garching (Germany); Ackermann, D.; Block, M.; Herfurth, F.; Hebberger, F.P.; Hofmann, S.; Mann, R. [Gesellschaft fur Schwerionenforschung, Darmstadt (Germany)

    2007-10-15

    For the investigation of the atomic level structure of heavy elements which can only be produced at on-line facilities such as GSI (Darmstadt, Germany), a novel experimental procedure has been developed. It is based on Radiation Detected Resonance Ionization Spectroscopy (RADRIS) and can be applied to elements like nobelium produced at rates of a few ions per second. Fusion reaction products are separated from the primary beam by the velocity filter SHIP at GSI, stopped in a buffer gas cell, collected on a tantalum filament and then re-evaporated as atoms. The ions produced by resonance ionization with tunable laser beams are detected via their characteristic alpha decay. First on-line experiments on alpha-active {sup 155}Yb, which is supposed to have an atomic level structure similar to nobelium, were performed. These test experiments focused on the optimization of the collection and re-evaporation process of the radioactive ions, the laser ionization efficiency and the detection via alpha decay. An overall efficiency for RADRIS of 0.8% with respect to the target production rate was measured. While further improvements of this efficiency are in progress it should already be sufficient for the search for atomic levels in nobelium. (authors)

  2. Towards optical spectroscopy of the element nobelium (Z = 102) in a buffer gas cell. First on-line experiments on 155Yb at the velocity filter SHIP with a novel ion collection and atom re-evaporation method of high efficiency

    International Nuclear Information System (INIS)

    Backe, H.; Kunz, P.; Lauth, W.; Dretzke, A.; Horn, R.; Kolb, T.; Laatiaoui, M.; Sewtz, M.; Ackermann, D.; Block, M.; Herfurth, F.; Hebberger, F.P.; Hofmann, S.; Mann, R.

    2007-01-01

    For the investigation of the atomic level structure of heavy elements which can only be produced at on-line facilities such as GSI (Darmstadt, Germany), a novel experimental procedure has been developed. It is based on Radiation Detected Resonance Ionization Spectroscopy (RADRIS) and can be applied to elements like nobelium produced at rates of a few ions per second. Fusion reaction products are separated from the primary beam by the velocity filter SHIP at GSI, stopped in a buffer gas cell, collected on a tantalum filament and then re-evaporated as atoms. The ions produced by resonance ionization with tunable laser beams are detected via their characteristic alpha decay. First on-line experiments on alpha-active 155 Yb, which is supposed to have an atomic level structure similar to nobelium, were performed. These test experiments focused on the optimization of the collection and re-evaporation process of the radioactive ions, the laser ionization efficiency and the detection via alpha decay. An overall efficiency for RADRIS of 0.8% with respect to the target production rate was measured. While further improvements of this efficiency are in progress it should already be sufficient for the search for atomic levels in nobelium. (authors)

  3. Structure-Dependent Water-Induced Linear Reduction Model for Predicting Gas Diffusivity and Tortuosity in Repacked and Intact Soil

    DEFF Research Database (Denmark)

    Møldrup, Per; Chamindu, T. K. K. Deepagoda; Hamamoto, S.

    2013-01-01

    The soil-gas diffusion is a primary driver of transport, reactions, emissions, and uptake of vadose zone gases, including oxygen, greenhouse gases, fumigants, and spilled volatile organics. The soil-gas diffusion coefficient, Dp, depends not only on soil moisture content, texture, and compaction...... but also on the local-scale variability of these. Different predictive models have been developed to estimate Dp in intact and repacked soil, but clear guidelines for model choice at a given soil state are lacking. In this study, the water-induced linear reduction (WLR) model for repacked soil is made...... air) in repacked soils containing between 0 and 54% clay. With Cm = 2.1, the SWLR model on average gave excellent predictions for 290 intact soils, performing well across soil depths, textures, and compactions (dry bulk densities). The SWLR model generally outperformed similar, simple Dp/Do models...

  4. Free microparticles—An inducing mechanism of pre-firing in high pressure gas switches for fast linear transformer drivers

    Science.gov (United States)

    Li, Xiaoang; Pei, Zhehao; Wu, Zhicheng; Zhang, Yuzhao; Liu, Xuandong; Li, Yongdong; Zhang, Qiaogen

    2018-03-01

    Microparticle initiated pre-firing of high pressure gas switches for fast linear transformer drivers (FLTDs) is experimentally and theoretically verified. First, a dual-electrode gas switch equipped with poly-methyl methacrylate baffles is used to capture and collect the microparticles. By analyzing the electrode surfaces and the collecting baffles by a laser scanning confocal microscope, microparticles ranging in size from tens of micrometers to over 100 μm are observed under the typical working conditions of FLTDs. The charging and movement of free microparticles in switch cavity are studied, and the strong DC electric field drives the microparticles to bounce off the electrode. Three different modes of free microparticle motion appear to be responsible for switch pre-firing. (i) Microparticles adhere to the electrode surface and act as a fixed protrusion which distorts the local electric field and initiates the breakdown in the gap. (ii) One particle escapes toward the opposite electrode and causes a near-electrode microdischarge, inducing the breakdown of the residual gap. (iii) Multiple moving microparticles are occasionally in cascade, leading to pre-firing. Finally, as experimental verification, repetitive discharges at ±90 kV are conducted in a three-electrode field-distortion gas switch, with two 8 mm gaps and pressurized with nitrogen. An ultrasonic probe is employed to monitor the bounce signals. In pre-firing incidents, the bounce is detected shortly before the collapse of the voltage waveform, which demonstrates that free microparticles contribute significantly to the mechanism that induces pre-firing in FLTD gas switches.

  5. Free microparticles-An inducing mechanism of pre-firing in high pressure gas switches for fast linear transformer drivers.

    Science.gov (United States)

    Li, Xiaoang; Pei, Zhehao; Wu, Zhicheng; Zhang, Yuzhao; Liu, Xuandong; Li, Yongdong; Zhang, Qiaogen

    2018-03-01

    Microparticle initiated pre-firing of high pressure gas switches for fast linear transformer drivers (FLTDs) is experimentally and theoretically verified. First, a dual-electrode gas switch equipped with poly-methyl methacrylate baffles is used to capture and collect the microparticles. By analyzing the electrode surfaces and the collecting baffles by a laser scanning confocal microscope, microparticles ranging in size from tens of micrometers to over 100 μm are observed under the typical working conditions of FLTDs. The charging and movement of free microparticles in switch cavity are studied, and the strong DC electric field drives the microparticles to bounce off the electrode. Three different modes of free microparticle motion appear to be responsible for switch pre-firing. (i) Microparticles adhere to the electrode surface and act as a fixed protrusion which distorts the local electric field and initiates the breakdown in the gap. (ii) One particle escapes toward the opposite electrode and causes a near-electrode microdischarge, inducing the breakdown of the residual gap. (iii) Multiple moving microparticles are occasionally in cascade, leading to pre-firing. Finally, as experimental verification, repetitive discharges at ±90 kV are conducted in a three-electrode field-distortion gas switch, with two 8 mm gaps and pressurized with nitrogen. An ultrasonic probe is employed to monitor the bounce signals. In pre-firing incidents, the bounce is detected shortly before the collapse of the voltage waveform, which demonstrates that free microparticles contribute significantly to the mechanism that induces pre-firing in FLTD gas switches.

  6. Temperature buffer test. Dismantling operation

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2010-12-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  7. Temperature buffer test. Dismantling operation

    International Nuclear Information System (INIS)

    Aakesson, Mattias

    2010-12-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  8. Gas-Induced Water-hammer Loads Calculation for Safety Related Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seungchan; Yoon, Dukjoo [Korea Hydro and Nuclear Power Co., LTd, Daejeon (Korea, Republic of); Lee, Dooyong [Seoul National Univ., Seoul (Korea, Republic of)

    2013-05-15

    Of particular interest, gas accumulation can result in system pressure transient in pump discharge piping following a pump start. Consequently, this evolves into a gas-water, a water-hammer event and the accompanying force imbalances on the piping segments can be sufficient to challenge the piping supports and restraint. This paper describes an method performing to the water-hammer loads to determine the maximum loading that would occur in the piping system following the safety injection signal and to evaluate its integrity. For a given gas void volumes in the discharge piping, the result of the calculation shows the maximum loads of 18,894.2psi, which is smaller than the allowable criteria. Also, the maximum peak axial force imbalances acting on the support is 1,720lbf as above.

  9. Gas-Induced Water-hammer Loads Calculation for Safety Related Systems

    International Nuclear Information System (INIS)

    Lee, Seungchan; Yoon, Dukjoo; Lee, Dooyong

    2013-01-01

    Of particular interest, gas accumulation can result in system pressure transient in pump discharge piping following a pump start. Consequently, this evolves into a gas-water, a water-hammer event and the accompanying force imbalances on the piping segments can be sufficient to challenge the piping supports and restraint. This paper describes an method performing to the water-hammer loads to determine the maximum loading that would occur in the piping system following the safety injection signal and to evaluate its integrity. For a given gas void volumes in the discharge piping, the result of the calculation shows the maximum loads of 18,894.2psi, which is smaller than the allowable criteria. Also, the maximum peak axial force imbalances acting on the support is 1,720lbf as above

  10. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine equivalent...

  11. THE BUFFER CAPACITY OF AIRWAY EPITHELIAL SECRETIONS

    Directory of Open Access Journals (Sweden)

    Dusik eKim

    2014-06-01

    Full Text Available The pH of airway epithelial secretions influences bacterial killing and mucus properties and is reduced by acidic pollutants, gastric reflux, and respiratory diseases such as cystic fibrosis (CF. The effect of acute acid loads depends on buffer capacity, however the buffering of airway secretions has not been well characterized. In this work we develop a method for titrating micro-scale (30 µl volumes and use it to study fluid secreted by the human airway epithelial cell line Calu-3, a widely used model for submucosal gland serous cells. Microtitration curves revealed that HCO3- is the major buffer. Peak buffer capacity (β increased from 17 to 28 mM/pH during forskolin stimulation, and was reduced by >50% in fluid secreted by cystic fibrosis transmembrane conductance regulator (CFTR-deficient Calu-3 monolayers, confirming an important role of CFTR in HCO3- secretion. Back-titration with NaOH revealed non-volatile buffer capacity due to proteins synthesized and released by the epithelial cells. Lysozyme and mucin concentrations were too low to buffer Calu-3 fluid significantly, however model titrations of porcine gastric mucins at concentrations near the sol-gel transition suggest that mucins may contribute to the buffer capacity of ASL in vivo. We conclude that CFTR-dependent HCO3- secretion and epithelially-derived proteins are the predominant buffers in Calu-3 secretions.

  12. Shock buffer for nuclear control assembly

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1977-01-01

    A shock buffer is provided for the gradual deceleration of a rapidly descending control element assembly in a nuclear reactor. The interactive buffer components are associated respectively with the movable control element assembly and part of the upper guide structure independent of and spaced from the fuel assemblies of the reactor

  13. ISM-induced erosion and gas-dynamical drag in the Oort Cloud

    International Nuclear Information System (INIS)

    Stern, S.A.

    1990-01-01

    The model presently used to examine the physical interactions between the ISM and the Oort Cloud can account for sputtering, sticking, and grain-impact erosion, as well as gas drag, by envisioning the ISM as a multiphase medium with distinct atomic and molecular cloud-phase regimes and coronal and warm/ambient gas-phase regimes. Erosion, which reduces the effectiveness of the thermal and radiation-damage processes acting on cometary surfaces in the Oort cloud, is found to be the dominant ISM interaction; ISM drag effects were found to efficiently remove submicron particles from the Cloud. 67 refs

  14. ISM-induced erosion and gas-dynamical drag in the Oort Cloud

    Science.gov (United States)

    Stern, S. Alan

    1990-01-01

    The model presently used to examine the physical interactions between the ISM and the Oort Cloud can account for sputtering, sticking, and grain-impact erosion, as well as gas drag, by envisioning the ISM as a multiphase medium with distinct atomic and molecular cloud-phase regimes and coronal and warm/ambient gas-phase regimes. Erosion, which reduces the effectiveness of the thermal and radiation-damage processes acting on cometary surfaces in the Oort cloud, is found to be the dominant ISM interaction; ISM drag effects were found to efficiently remove submicron particles from the Cloud.

  15. Simulation study on single event burnout in linear doping buffer layer engineered power VDMOSFET

    Science.gov (United States)

    Yunpeng, Jia; Hongyuan, Su; Rui, Jin; Dongqing, Hu; Yu, Wu

    2016-02-01

    The addition of a buffer layer can improve the device's secondary breakdown voltage, thus, improving the single event burnout (SEB) threshold voltage. In this paper, an N type linear doping buffer layer is proposed. According to quasi-stationary avalanche simulation and heavy ion beam simulation, the results show that an optimized linear doping buffer layer is critical. As SEB is induced by heavy ions impacting, the electric field of an optimized linear doping buffer device is much lower than that with an optimized constant doping buffer layer at a given buffer layer thickness and the same biasing voltages. Secondary breakdown voltage and the parasitic bipolar turn-on current are much higher than those with the optimized constant doping buffer layer. So the linear buffer layer is more advantageous to improving the device's SEB performance. Project supported by the National Natural Science Foundation of China (No. 61176071), the Doctoral Fund of Ministry of Education of China (No. 20111103120016), and the Science and Technology Program of State Grid Corporation of China (No. SGRI-WD-71-13-006).

  16. Buffer sizing for multi-hop networks

    KAUST Repository

    Shihada, Basem

    2014-01-28

    A cumulative buffer may be defined for an interference domain in a wireless mesh network and distributed among nodes in the network to maintain or improve capacity utilization of network resources in the interference domain without increasing packet queuing delay times. When an interference domain having communications links sharing resources in a network is identified, a cumulative buffer size is calculated. The cumulative buffer may be distributed among buffers in each node of the interference domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed when the network conditions change.

  17. Optimization of protein buffer cocktails using Thermofluor.

    Science.gov (United States)

    Reinhard, Linda; Mayerhofer, Hubert; Geerlof, Arie; Mueller-Dieckmann, Jochen; Weiss, Manfred S

    2013-02-01

    The stability and homogeneity of a protein sample is strongly influenced by the composition of the buffer that the protein is in. A quick and easy approach to identify a buffer composition which increases the stability and possibly the conformational homogeneity of a protein sample is the fluorescence-based thermal-shift assay (Thermofluor). Here, a novel 96-condition screen for Thermofluor experiments is presented which consists of buffer and additive parts. The buffer screen comprises 23 different buffers and the additive screen includes small-molecule additives such as salts and nucleotide analogues. The utilization of small-molecule components which increase the thermal stability of a protein sample frequently results in a protein preparation of higher quality and quantity and ultimately also increases the chances of the protein crystallizing.

  18. How Pt nanoparticles affect TiO2-induced gas-phase photocatalytic oxidation reactions

    NARCIS (Netherlands)

    Fraters, B.D.; Amrollahi Buky, Rezvaneh; Mul, Guido

    2015-01-01

    The effect of Pt nanoparticles on the gas-phase photocatalytic oxidation activity of TiO2 is shown to be largely dependent on the molecular functionality of the substrate. We demonstrate that Pt nanoparticles decrease rates in photocatalytic oxidation of propane, whereas a strong beneficial effect

  19. Optimizing of operational strategies in producting gas fields mitigating induced seismic risk

    NARCIS (Netherlands)

    Chitu, A.G.; Leeuwenburgh, O.; Candela, T.G.G.; Osinga, S.; Kraaijpoel, D.A.; Wassing, B.B.T.

    2017-01-01

    Pore pressure changes caused by the production of gas from reservoir rocks result in reservoir compaction, stress changes on faults, potential fault reactivation and related seismic activity. This seismic activity is expected to be affected by the amount of pressure change, the spatial distribution

  20. γ-irradiation induced zinc ferrites and their enhanced room-temperature ammonia gas sensing properties

    Science.gov (United States)

    Raut, S. D.; Awasarmol, V. V.; Ghule, B. G.; Shaikh, S. F.; Gore, S. K.; Sharma, R. P.; Pawar, P. P.; Mane, R. S.

    2018-03-01

    Zinc ferrite (ZnFe2O4) nanoparticles (NPs), synthesized using a facile and cost-effective sol-gel auto-combustion method, were irradiated with 2 and 5 kGy γ-doses using 60Co as a radioactive source. Effect of γ-irradiation on the structure, morphology, pore-size and pore-volume and room-temperature (300 K) gas sensor performance has been measured and reported. Both as-synthesized and γ-irradiated ZnFe2O4 NPs reveal remarkable gas sensor activity to ammonia in contrast to methanol, ethanol, acetone and toluene volatile organic gases. The responses of pristine, 2 and 5 kGy γ-irradiated ZnFe2O4 NPs are respectively 55%, 66% and 81% @100 ppm concentration of ammonia, signifying an importance of γ-irradiation for enhancing the sensitivity, selectivity and stability of ZnFe2O4 NPs as ammonia gas sensors. Thereby, due to increase in surface area and crystallinity on γ-doses, the γ-irradiation improves the room-temperature ammonia gas sensing performance of ZnFe2O4.

  1. Nitrogen gas plasma treatment of bacterial spores induces oxidative stress that damages the genomic DNA.

    Science.gov (United States)

    Sakudo, Akikazu; Toyokawa, Yoichi; Nakamura, Tetsuji; Yagyu, Yoshihito; Imanishi, Yuichiro

    2017-01-01

    Gas plasma, produced by a short high‑voltage pulse generated from a static induction thyristor power supply [1.5 kilo pulse/sec (kpps)], was demonstrated to inactivate Geobacillus stearothermophilus spores (decimal reduction time at 15 min, 2.48 min). Quantitative polymerase chain reaction and enzyme‑linked immunosorbent assays further indicated that nitrogen gas plasma treatment for 15 min decreased the level of intact genomic DNA and increased the level of 8-hydroxy-2'-deoxyguanosine, a major product of DNA oxidation. Three potential inactivation factors were generated during operation of the gas plasma instrument: Heat, longwave ultraviolet-A and oxidative stress (production of hydrogen peroxide, nitrite and nitrate). Treatment of the spores with hydrogen peroxide (3x2‑4%) effectively inactivated the bacteria, whereas heat treatment (100˚C), exposure to UV-A (75‑142 mJ/cm2) and 4.92 mM peroxynitrite (•ONOO‑), which is decomposed into nitrite and nitrate, did not. The results of the present study suggest the gas plasma treatment inactivates bacterial spores primarily by generating hydrogen peroxide, which contributes to the oxidation of the host genomic DNA.

  2. Sound generating flames of a gas turbine burner observed by laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Hubschmid, W; Inauen, A.; Bombach, R.; Kreutner, W.; Schenker, S.; Zajadatz, M. [Alstom (Switzerland); Motz, C. [Alstom (Switzerland); Haffner, K. [Alstom (Switzerland); Paschereit, C.O. [Alstom (Switzerland)

    2002-03-01

    We performed 2-D OH LIF measurements to investigate the sound emission of a gas turbine combustor. The measured LIF signal was averaged over pulses at constant phase of the dominant acoustic oscillation. A periodic variation in intensity and position of the signal is observed and it is related to the measured sound intensity. (author)

  3. The hormone response element mimic sequence of GAS5 lncRNA is sufficient to induce apoptosis in breast cancer cells

    Science.gov (United States)

    Pickard, Mark R.; Williams, Gwyn T.

    2016-01-01

    Growth arrest-specific 5 (GAS5) lncRNA promotes apoptosis, and its expression is down-regulated in breast cancer. GAS5 lncRNA is a decoy of glucocorticoid/related receptors; a stem-loop sequence constitutes the GAS5 hormone response element mimic (HREM), which is essential for the regulation of breast cancer cell apoptosis. This preclinical study aimed to determine if the GAS5 HREM sequence alone promotes the apoptosis of breast cancer cells. Nucleofection of hormone-sensitive and –insensitive breast cancer cell lines with a GAS5 HREM DNA oligonucleotide increased both basal and ultraviolet-C-induced apoptosis, and decreased culture viability and clonogenic growth, similar to GAS5 lncRNA. The HREM oligonucleotide demonstrated similar sequence specificity to the native HREM for its functional activity and had no effect on endogenous GAS5 lncRNA levels. Certain chemically modified HREM oligonucleotides, notably DNA and RNA phosphorothioates, retained pro-apoptotic. activity. Crucially the HREM oligonucleotide could overcome apoptosis resistance secondary to deficient endogenous GAS5 lncRNA levels. Thus, the GAS5 lncRNA HREM sequence alone is sufficient to induce apoptosis in breast cancer cells, including triple-negative breast cancer cells. These findings further suggest that emerging knowledge of structure/function relationships in the field of lncRNA biology can be exploited for the development of entirely novel, oligonucleotide mimic-based, cancer therapies. PMID:26862727

  4. The exponential rise of induced seismicity with increasing stress levels in the Groningen gas field and its implications for controlling seismic risk

    Science.gov (United States)

    Bourne, S. J.; Oates, S. J.; van Elk, J.

    2018-06-01

    Induced seismicity typically arises from the progressive activation of recently inactive geological faults by anthropogenic activity. Faults are mechanically and geometrically heterogeneous, so their extremes of stress and strength govern the initial evolution of induced seismicity. We derive a statistical model of Coulomb stress failures and associated aftershocks within the tail of the distribution of fault stress and strength variations to show initial induced seismicity rates will increase as an exponential function of induced stress. Our model provides operational forecasts consistent with the observed space-time-magnitude distribution of earthquakes induced by gas production from the Groningen field in the Netherlands. These probabilistic forecasts also match the observed changes in seismicity following a significant and sustained decrease in gas production rates designed to reduce seismic hazard and risk. This forecast capability allows reliable assessment of alternative control options to better inform future induced seismic risk management decisions.

  5. COMBINATIONS OF BUFFER-STOCKS AND BUFFER-FUNDS FOR WOOL PRICE STABILISATION IN AUSTRALIA

    OpenAIRE

    Moir, Brian; Piggott, Roley R.

    1991-01-01

    In this paper a preliminary analysis is presented of a combined buffer-fund and buffer-stock as an alternative to a pure buffer-fund or a pure buffer stock for stabilising wool prices. The alternatives analysed are designed so that each provides the same prices to producers as did the Reserve Price Scheme over the period of analysis. Least-cost combinations of policy instruments are derived. The results show that there is considerable potential for cost savings to be made by combining buffer-...

  6. Pan-viral specificity of IFN-induced genes reveals new roles for cGAS in innate immunity

    Science.gov (United States)

    Schoggins, John W.; MacDuff, Donna A.; Imanaka, Naoko; Gainey, Maria D.; Shrestha, Bimmi; Eitson, Jennifer L.; Mar, Katrina B.; Richardson, R. Blake; Ratushny, Alexander V.; Litvak, Vladimir; Dabelic, Rea; Manicassamy, Balaji; Aitchison, John D.; Aderem, Alan; Elliott, Richard M.; García-Sastre, Adolfo; Racaniello, Vincent; Snijder, Eric J.; Yokoyama, Wayne M.; Diamond, Michael S.; Virgin, Herbert W.; Rice, Charles M.

    2014-01-01

    The type I interferon (IFN) response protects cells from viral infection by inducing hundreds of interferon-stimulated genes (ISGs), some of which encode direct antiviral effectors. Recent screening studies have begun to catalogue ISGs with antiviral activity against several RNA and DNA viruses. However, antiviral ISG specificity across multiple distinct classes of viruses remains largely unexplored. Here we used an ectopic expression assay to screen a library of more than 350 human ISGs for effects on 14 viruses representing 7 families and 11 genera. We show that 47 genes inhibit one or more viruses, and 25 genes enhance virus infectivity. Comparative analysis reveals that the screened ISGs target positive-sense single-stranded RNA viruses more effectively than negative-sense single-stranded RNA viruses. Gene clustering highlights the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS, also known as MB21D1) as a gene whose expression also broadly inhibits several RNA viruses. In vitro, lentiviral delivery of enzymatically active cGAS triggers a STING-dependent, IRF3-mediated antiviral program that functions independently of canonical IFN/STAT1 signalling. In vivo, genetic ablation of murine cGAS reveals its requirement in the antiviral response to two DNA viruses, and an unappreciated contribution to the innate control of an RNA virus. These studies uncover new paradigms for the preferential specificity of IFN-mediated antiviral pathways spanning several virus families.

  7. Spectroscopic investigations of high-power laser-induced dielectric breakdown in gas mixtures containing carbon monoxide.

    Science.gov (United States)

    Civis, Svatopluk; Babánková, Dagmar; Cihelka, Jaroslav; Sazama, Petr; Juha, Libor

    2008-08-07

    Large-scale plasma was created in gas mixtures containing carbon monoxide by high-power laser-induced dielectric breakdown (LIDB). The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth's early atmosphere. A multiple-centimeter-sized fireball was created by focusing a single 85 J, 450 ps near-infrared laser pulse into the center of a 15 L gas cell. The excited reaction intermediates that formed in various stages of the LIDB plasma chemical evolution were investigated by optical emission spectroscopy (OES) with temporal resolution. Special attention was paid to any OES signs of molecular ions. However, carbon monoxide cations were registered only if their production was enhanced by Penning ionization, i.e., excess He was added to the CO. The chemical consequences of laser-produced plasma generation in a CO-N 2-H 2O mixture were investigated using high resolution Fourier-transform infrared absorption spectroscopy (FTIR) and gas chromatography (GC). Several simple inorganic and organic compounds were identified in the reaction mixture exposed to ten laser sparks. H 2 (18)O was used to avoid possible contamination. The large laser spark triggered more complex reactivity originating in carbon monoxide than expected, when taking into account the strong triple bond of carbon monoxide causing typically inefficient dissociation of this molecule in electrical discharges.

  8. cGAS-Mediated Innate Immunity Spreads Intercellularly through HIV-1 Env-Induced Membrane Fusion Sites.

    Science.gov (United States)

    Xu, Shuting; Ducroux, Aurélie; Ponnurangam, Aparna; Vieyres, Gabrielle; Franz, Sergej; Müsken, Mathias; Zillinger, Thomas; Malassa, Angelina; Ewald, Ellen; Hornung, Veit; Barchet, Winfried; Häussler, Susanne; Pietschmann, Thomas; Goffinet, Christine

    2016-10-12

    Upon sensing cytoplasmic retroviral DNA in infected cells, cyclic GMP-AMP (cGAMP) synthase (cGAS) produces the cyclic dinucleotide cGAMP, which activates STING to trigger a type I interferon (IFN) response. We find that membrane fusion-inducing contact between donor cells expressing the HIV envelope (Env) and primary macrophages endogenously expressing the HIV receptor CD4 and coreceptor enable intercellular transfer of cGAMP. This cGAMP exchange results in STING-dependent antiviral IFN responses in target macrophages and protection from HIV infection. Furthermore, under conditions allowing cell-to-cell transmission of HIV-1, infected primary T cells, but not cell-free virions, deliver cGAMP to autologous macrophages through HIV-1 Env and CD4/coreceptor-mediated membrane fusion sites and induce a STING-dependent, but cGAS-independent, IFN response in target cells. Collectively, these findings identify an infection-specific mode of horizontal transfer of cGAMP between primary immune cells that may boost antiviral responses, particularly in infected tissues in which cell-to-cell transmission of virions exceeds cell-free infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Collision induced dissociation of protonated N-nitrosodimethylamine by ion trap mass spectrometry: Ultimate carcinogens in gas phase

    Science.gov (United States)

    Kulikova, Natalia; Baker, Michael; Gabryelski, Wojciech

    2009-12-01

    Collision induced dissociation of protonated N-nitrosodimethylamine (NDMA) and isotopically labeled N-nitrosodimethyl-d6-amine (NDMA-d6) was investigated by sequential ion trap mass spectrometry to establish mechanisms of gas phase reactions leading to intriguing products of this potent carcinogen. The fragmentation of (NDMA + H+) occurs via two dissociation pathways. In the alkylation pathway, homolytic cleavage of the N-O bond of N-dimethyl, N'-hydroxydiazenium ion generates N-dimethyldiazenium distonic ion which reacts further by a CH3 radical loss to form methanediazonium ion. Both methanediazonium ion and its precursor are involved in ion/molecule reactions. Methanediazonium ion showed to be capable of methylating water and methanol molecules in the gas phase of the ion trap and N-dimethyldiazenium distonic ion showed to abstract a hydrogen atom from a solvent molecule. In the denitrosation pathway, a tautomerization of N-dimethyl, N'-hydroxydiazenium ion to N-nitrosodimethylammonium intermediate ion results in radical cleavage of the N-N bond of the intermediate ion to form N-dimethylaminium radical cation which reacts further through [alpha]-cleavage to generate N-methylmethylenimmonium ion. Although the reactions of NDMA in the gas phase are different to those for enzymatic conversion of NDMA in biological systems, each activation method generates the same products. We will show that collision induced dissociation of N-nitrosodiethylamine (NDEA) and N-nitrosodipropylamine (NDPA) is also a feasible approach to gain information on formation, stability, and reactivity of alkylating agents originating from NDEA and NDPA. Investigating such biologically relevant, but highly reactive intermediates in the condensed phase is hampered by the short life-times of these transient species.

  10. Temperature buffer test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2012-04-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first {approx}1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last {approx}600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day {approx}1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day {approx}1,500 to day {approx}1

  11. Temperature buffer test. Final report

    International Nuclear Information System (INIS)

    Aakesson, Mattias

    2012-04-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first ∼1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last ∼600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day ∼1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day ∼1,500 to day ∼1,800. The sensors data concerning

  12. Swift heavy ion induced modification in polycarbonate membrane for gas separation

    International Nuclear Information System (INIS)

    Rajesh Kumar; Prasad, Rajendra; Vijay, Y.K.; Das, D.

    2003-01-01

    Polymeric membranes are extensively used for commercial gas separation applications. Makrofol-KG (polycarbonate) is a glassy polymer. 40 μm thick sheet of Makrofol-KG was irradiated with 40 Ar (14.9 MeV/n) of fluence 10 3 ions/cm 2 and 20 μm thick sheet with 5.3 MeV α-particles of fluence 10 7 ions/cm 2 . The permeability of these polycarbonate membranes for H 2 and CO 2 was measured and also after etching in 6 N NaOH at 60 degC for different periods. Permeability is found to be increased with etching time. At a definite time, critical etching time, the permeability rapidly increases in PC. Positron annihilation lifetimes for unirradiated and irradiated membranes were measured with fast fast coincidence system to study the correlation of free volume hole concentration with gas separation properties. (author)

  13. Pressure disequilibria induced by rapid valve closure in noble gas extraction lines

    Science.gov (United States)

    Morgan, Leah; Davidheiser-Kroll, Brett

    2015-01-01

    Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000 aliquants. Herein we explore the causes and effects of this problem, which is the result of volume changes during valve closure. We also present a solution in the form of an electropneumatic pressure regulator that can precisely control valve motion. This solution reduces the effect to ∼0.3% even after 10,000 aliquants have been removed from a 10 L reservoir.

  14. Laser induced aluminiun plasma analysis by optical emission spectroscopy in a nitrogen background gas

    International Nuclear Information System (INIS)

    Chamorro, J C; Uzuriaga, J; Riascos, H

    2012-01-01

    We studied an Al plasma generated by a Nd:YAG laser with a laser fluence of 4 J/cm 2 , a wavelength of 1064 nm, energy pulse of 500 mJ and 10 Hz repetition rate. We studied their spectral characteristics at various ambient nitrogen pressures by optical emission spectroscopy (OES). The N 2 gas pressure was varied from 20 mTorr to 150 mTorr. In Al plume, both atomic and ionic spectra were observed. The electron temperature and electron number density of the plume as of the function ambient gas pressure were determined. The electron temperature was calculated by using the Boltzmann-plot method and the number density was calculated considering the stark effect as dominating on the emission lines.

  15. Pressure disequilibria induced by rapid valve closure in noble gas extraction lines

    Science.gov (United States)

    Morgan, Leah E.; Davidheiser-Kroll, Brett

    2015-06-01

    Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000 aliquants. Herein we explore the causes and effects of this problem, which is the result of volume changes during valve closure. We also present a solution in the form of an electropneumatic pressure regulator that can precisely control valve motion. This solution reduces the effect to ˜0.3% even after 10,000 aliquants have been removed from a 10 L reservoir.

  16. Nanocrystalline AL2 O2 powders produced by laser induced gas phase reactions

    International Nuclear Information System (INIS)

    Borsella, E.; Botti, S.; Martelli, S.; Zappa, G.; Giorgi, R.; Turt, S.

    1993-01-01

    Nanocrystalline Al 2 O 3 powders were successfully synthesized by a CO 2 laser-driven gas-phase reaction involving trimethylaluminium (Al(CH 3 ) 3 ) and nitrous-oxide (N 2 O). Ethylene (C 2 H 4 ) was added as gas sensitizer. The as-synthesized powder particles showed a considerable carbon contamination and an amorphous-like structure. After thermal treatment at 1200-1400 degrees C, the powder was transformed to hexagonal a-Al 2 O 3 with very low carbon contamination as confirmed by X-ray diffraction, X-ray photo-electron spectroscopy and chemical analysis. The calcinated powders resulted to be spherical single crystal nanoparticles with a mean size of 15-20 nm, as determined by X-ray diffraction, electron microscopy and B.E.T. specific surface measurements. The laser synthesized Al 2 O 3 particles are well suited dispersoids for intermetallic alloy technology

  17. Medium-induced change of the optical response of metal clusters in rare-gas matrices

    Science.gov (United States)

    Xuan, Fengyuan; Guet, Claude

    2017-10-01

    Interaction with the surrounding medium modifies the optical response of embedded metal clusters. For clusters from about ten to a few hundreds of silver atoms, embedded in rare-gas matrices, we study the environment effect within the matrix random phase approximation with exact exchange (RPAE) quantum approach, which has proved successful for free silver clusters. The polarizable surrounding medium screens the residual two-body RPAE interaction, adds a polarization term to the one-body potential, and shifts the vacuum energy of the active delocalized valence electrons. Within this model, we calculate the dipole oscillator strength distribution for Ag clusters embedded in helium droplets, neon, argon, krypton, and xenon matrices. The main contribution to the dipole surface plasmon red shift originates from the rare-gas polarization screening of the two-body interaction. The large size limit of the dipole surface plasmon agrees well with the classical prediction.

  18. Dynamic mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Taniguchi, Wataru

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

  19. Buffer-regulated biocorrosion of pure magnesium.

    Science.gov (United States)

    Kirkland, Nicholas T; Waterman, Jay; Birbilis, Nick; Dias, George; Woodfield, Tim B F; Hartshorn, Richard M; Staiger, Mark P

    2012-02-01

    Magnesium (Mg) alloys are being actively investigated as potential load-bearing orthopaedic implant materials due to their biodegradability in vivo. With Mg biomaterials at an early stage in their development, the screening of alloy compositions for their biodegradation rate, and hence biocompatibility, is reliant on cost-effective in vitro methods. The use of a buffer to control pH during in vitro biodegradation is recognised as critically important as this seeks to mimic pH control as it occurs naturally in vivo. The two different types of in vitro buffer system available are based on either (i) zwitterionic organic compounds or (ii) carbonate buffers within a partial-CO(2) atmosphere. This study investigated the influence of the buffering system itself on the in vitro corrosion of Mg. It was found that the less realistic zwitterion-based buffer did not form the same corrosion layers as the carbonate buffer, and was potentially affecting the behaviour of the hydrated oxide layer that forms on Mg in all aqueous environments. Consequently it was recommended that Mg in vitro experiments use the more biorealistic carbonate buffering system when possible.

  20. Evaporation-induced gas-phase flows at selective laser melting

    Science.gov (United States)

    Zhirnov, I.; Kotoban, D. V.; Gusarov, A. V.

    2018-02-01

    Selective laser melting is the method for 3D printing from metals. A solid part is built from powder layer-by-layer. A continuum-wave laser beam scans every powder layer to fuse powder. The process is studied with a high-speed CCD camera at the frame rate of 104 fps and the resolution up to 5 µm per pixel. Heat transfer and evaporation in the laser-interaction zone are numerically modeled. Droplets are ejected from the melt pool in the direction around the normal to the melt surface and the powder particles move in the horizontal plane toward the melt pool. A vapor jet is observed in the direction of the normal to the melt surface. The velocities of the droplets, the powder particles, and the jet flow and the mass loss due to evaporation are measured. The gas flow around the vapor jet is calculated by Landau's model of submerged jet. The measured velocities of vapor, droplets, and powder particles correlate with the calculated flow field. The obtained results show the importance of evaporation and the flow of the vapor and the ambient gas. These gas-dynamic phenomena can explain the formation of the denudated zones and the instability at high-energy input.

  1. Radiation-induced transformations of isolated organic molecules in solid rare gas matrices

    International Nuclear Information System (INIS)

    Feldman, V.I.

    1998-01-01

    Complete text of publication follows. The studies of radiation-chemical behaviour of isolated organic molecules in rigid inert media are of considerable interest for radiation chemistry and general structural chemistry. Previous efforts were limited to the ESR studies of radicals resulting from some small hydrocarbon molecules in frozen rare gas solutions. Recently, we developed an approach to the radiation chemistry of isolated organic molecules using classic matrix isolation procedure for sample preparation and a combination of ESR and IR spectroscopy for characterization of paramagnetic and diamagnetic species resulting form electron irradiation or organic molecules in solid rare gas matrices at 10-15 K. The results obtained reveal high efficiency of energy transfer from rare gas matrix to organic molecules. The total radiation-chemical yields of degradation of organic molecules in argon and xenon matrices were measured directly by IR spectroscopy. The studies of the effect of electron scavengers on the radiolysis of organic molecules in solid rare gases show that the main primary process is positive hole transfer from matrix to additive molecule. ESR spectra of a number of radical cations (alkanes, ethers, arenes) were first characterized in a low-disturbing environment. It was found that the electronic characteristics (IP, polarizability) of the matrix used had crucial effect on trapping and degradation of primary organic radical cations. Using matrices with various IP provides an unique possibility to examine the chemical meaning of excess energy resulting from exothermic positive hole transfer, that is, to follow the fate of excited cations in condensed phase

  2. Studying gas-sheared liquid film in horizontal rectangular duct with laser-induced fluorescence technique

    Science.gov (United States)

    Cherdantsev, Andrey; Hann, David; Azzopardi, Barry

    2013-11-01

    High-speed LIF-technique is applied to study gas-sheared liquid film in horizontal rectangular duct with 161 mm width. Instantaneous distributions of film thickness resolved in both longitudinal and transverse coordinates were obtained with a frequency of 10 kHz and spatial resolution from 0.125 mm to 0.04 mm. Processes of generation of fast and slow ripples by disturbance waves are the same as described in literature for downwards annular pipe flow. Disturbance waves are often localized by transverse coordinate and may have curved or slanted fronts. Fast ripples, covering disturbance waves, are typically horseshoe-shaped and placed in staggered order. Their characteristic transverse size is of order 1 cm and it decreases with gas velocity. Entrainment of liquid from film surface can also be visualized. Mechanisms of ripple disruption, known as ``bag break-up'' and ``ligament break-up,'' were observed. Both mechanisms may occur on the same disturbance waves. Various scenarios of droplet deposition on the liquid film are observed, including the impact, slow sinking and bouncing, characterized by different outcome of secondary droplets or entrapped bubbles. Number and size of bubbles increase greatly inside the disturbance waves. Both quantities increase with gas and liquid flow rates. EPSRC Programme Grant MEMPHIS (EP/K003976/1), and Roll-Royce UTC (Nottingham, for access to flow facility).

  3. Buffer protection in the installation phase

    International Nuclear Information System (INIS)

    Wimelius, Hans; Pusch, Roland

    2008-12-01

    The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving this and for providing alarm signals if the allowed pressure is

  4. Buffer protection in the installation phase

    Energy Technology Data Exchange (ETDEWEB)

    Wimelius, Hans (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Pusch, Roland (Geodevelopment International AB, Lund (Sweden))

    2008-12-15

    The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving

  5. Surface Water Protection by Productive Buffers

    DEFF Research Database (Denmark)

    Christen, Benjamin

    Vegetated riparian buffer zones are a widely recommended best management practice in agriculture for protecting surface and coastal waters from diffuse nutrient pollution. On the background of the EU funded research project NitroEurope (NEU; www.NitroEurope.eu), this study concentrates...... on the mitigation of nitrogen pollution in surface and groundwater, using riparian buffer zones for biomass production. The objectives are to map suitable areas for buffer implementation across the six NEU study landscapes, model tentative N-loss mitigation, calculate biomass production potential and economic...... designed for local conditions could be a way of protecting water quality attractive to many stakeholders....

  6. Anolyte recycling enhanced bioelectricity generation of the buffer-free single-chamber air-cathode microbial fuel cell.

    Science.gov (United States)

    Ren, Yueping; Chen, Jinli; Shi, Yugang; Li, Xiufen; Yang, Na; Wang, Xinhua

    2017-11-01

    Anolyte acidification is an inevitable restriction for the bioelectricity generation of buffer-free microbial fuel cells (MFCs). In this work, acidification of the buffer-free KCl anolyte has been thoroughly eliminated through anolyte recycling. The accumulated HCO 3 - concentration in the recycled KCl anolyte was above 50mM, which played as natural buffer and elevated the anolyte pH to above 8. The maximum power density (P max ) increased from 322.9mWm -2 to 527.2mWm -2 , which is comparable with the phosphate buffered MFC. Besides Geobacter genus, the gradually increased anolyte pH and conductivity induced the growing of electrochemically active Geoalkalibacter genus, in the anode biofilm. Anolyte recycling is a feasible strategy to strengthen the self-buffering capacity of buffer-free MFCs, thoroughly eliminate the anolyte acidification and prominently enhance the electric power. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Large scale gas injection test (Lasgit): Results from two gas injection tests

    International Nuclear Information System (INIS)

    Cuss, R. J.; Harrington, J. F.; Noy, D. J.; Wikman, A.; Sellin, P.

    2011-01-01

    This paper describes the initial results from a large scale gas injection test (Lasgit) performed at the Aespoe Hard Rock Laboratory (Sweden)). Lasgit is a full-scale field-scale experiment based on the Swedish KBS-3V repository concept, examining the processes controlling gas and water flow in compact buffer bentonite. The first 2 years of the test focused on the artificial hydration of the bentonite buffer. This was followed by a programme of hydraulic and gas injection tests which ran from day 843 to 1110. A further period of artificial hydration occurred from day 1110 to 1385, followed by a more complex programme of gas injection testing which remains on going (day 1385+). After 2 years of hydration, hydraulic conductivity and specific storage values in the lower filter array were found to range from 9 x 10 -14 to 1.6 x 10 -13 m/s and 5.5 x 10 -5 to 4.4 x 10 -4 m -1 respectively, with the injection filter FL903 yielding values of 7.5 x 10 -14 m/s and 2.5 x 10 -5 m -1 . A second set of hydraulic measurements were performed over 1 year and a half later yielding similar values, in the range 7.8 x 10 -14 m/s and 1.3 x 10 -13 m/s. The hydraulic conductivity of FL903 had reduced slightly to 5.3 x 10 -14 m/s while specific storage had increased to 4.0 x 10 -5 m -1 . Both datasets agree with laboratory values performed on small-scale saturated samples. Two sets of gas injection tests were performed over a 3 year period. During the course of testing, gas entry pressure was found to increase from around 650 kPa to approximately 1.3 MPa, indicative of the maturation of the clay. The sequential reduction in volumetric flow rate and lack of correlation between the rate of gas inflow and the gas pressure gradient observed during constant pressure steps prior to major gas entry, is suggestive of a reduction in gas permeability of the buffer and indicates only limited quantities of gas can be injected into the clay without interacting with the continuum stress field. Major gas

  8. Buffer sizing for multi-hop networks

    KAUST Repository

    Shihada, Basem; Jamshaid, Kamran

    2014-01-01

    domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed

  9. Moisture Buffer Value of Building Materials

    DEFF Research Database (Denmark)

    Rode, Carsten; Peuhkuri, Ruut; Time, Berit

    2007-01-01

    When building materials are in contact with indoor air they have some effect to moderate the variations of indoor humidity in occupied buildings. But so far there has been a lack of a standardized quantity to characterize the moisture buffering capability of materials. It has been the objective o...... is a test protocol which expresses how materials should be tested for determination of their Moisture Buffer Value. Finally, the paper presents some of the results of a Round Robin Test on various typical building materials that has been carried out in the project....... of a recent Nordic project to define such a quantity, and to declare it in the form of a NORDTEST method. The Moisture Buffer Value is the figure that has been developed in the project as a way to appraise the moisture buffer effect of materials, and the value is described in the paper. Also explained...

  10. Liquid growth hormone: preservatives and buffers

    DEFF Research Database (Denmark)

    Kappelgaard, Anne-Marie; Anders, Bojesen; Skydsgaard, Karen

    2004-01-01

    injection are dependent on the preservative used in the formulation and the concentration of GH. Injection pain may also be related to the buffer substance and injection volume. A liquid formulation of GH, Norditropi SimpleXx, has been developed that dispenses with the need for reconstitution before...... solution. More pain was also reported following large volume injections and following injections with solutions containing high protein concentrations. In summary, optimization of the preservative and buffer content of a liquid GH formulation may reduce injection pain and lead to improved patient...... administration. The formulation uses phenol (3 mg/ml) as a preservative (to protect product from microbial degradation or contamination) and histidine as a buffer. Alternative preservatives used in other GH formulations include m-cresol (9 mg/ml) and benzyl alcohol (3-9 mg/ml). Buffering agents include citrate...

  11. Calculating Buffer Zones: A Guide for Applicators

    Science.gov (United States)

    Buffer zones provide distance between the application block (i.e., edge of the treated field) and bystanders, in order to control pesticide exposure risk from soil fumigants. Distance requirements may be reduced by credits such as tarps.

  12. Buffer Strips for Riparian Zone Management

    National Research Council Canada - National Science Library

    1991-01-01

    This study provides a review of technical literature concerning the width of riparian buffer strips needed to protect water quality and maintain other important values provided by riparian ecosystem...

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

    Science.gov (United States)

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

    2010-10-01

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

  14. Shock wave-induced evaporation of water droplets in a gas-droplet mixture 646

    NARCIS (Netherlands)

    Goossens, H.W.J.; Cleijne, J.W.; Smolders, H.J.; Dongen, van M.E.H.

    1988-01-01

    A model is presented for the droplet evaporation process induced by a shock wave propagating in a fog. The model is based on the existence of a quasi-steady wet bulb state of the droplets during evaporation. It is shown that for moderate shock strength, Ma = <2,=" and=" droplet=" radii=" in=" the="

  15. Lucas Heights buffer zone: plan of management

    International Nuclear Information System (INIS)

    1986-01-01

    This plan is being used by the Commission as a guide for its management of the Lucas Heights buffer zone, which is essentially a circular area having a 1-6 km radius around the HIFAR reactor. Aspects covered by this plan include past uses, current use, objectives for buffer zone land management, emergency evacuation, resource conservation, archaeology, fire, access, rehabilitation of disturbed areas, resource management and plan implementation

  16. Extreme Threshold Failures Within a Heterogeneous Elastic Thin Sheet and the Spatial-Temporal Development of Induced Seismicity Within the Groningen Gas Field

    Science.gov (United States)

    Bourne, S. J.; Oates, S. J.

    2017-12-01

    Measurements of the strains and earthquakes induced by fluid extraction from a subsurface reservoir reveal a transient, exponential-like increase in seismicity relative to the volume of fluids extracted. If the frictional strength of these reactivating faults is heterogeneously and randomly distributed, then progressive failures of the weakest fault patches account in a general manner for this initial exponential-like trend. Allowing for the observable elastic and geometric heterogeneity of the reservoir, the spatiotemporal evolution of induced seismicity over 5 years is predictable without significant bias using a statistical physics model of poroelastic reservoir deformations inducing extreme threshold frictional failures of previously inactive faults. This model is used to forecast the temporal and spatial probability density of earthquakes within the Groningen natural gas reservoir, conditional on future gas production plans. Probabilistic seismic hazard and risk assessments based on these forecasts inform the current gas production policy and building strengthening plans.

  17. Gas-liquid hybrid discharge-induced degradation of diuron in aqueous solution.

    Science.gov (United States)

    Feng, Jingwei; Zheng, Zheng; Luan, Jingfei; Li, Kunquan; Wang, Lianhong; Feng, Jianfang

    2009-05-30

    Degradation of diuron in aqueous solution by gas-liquid hybrid discharge was investigated for the first time. The effect of output power intensity, pH value, Fe(2+) concentration, Cu(2+) concentration, initial conductivity and air flow rate on the degradation efficiency of diuron was examined. The results showed that the degradation efficiency of diuron increased with increasing output power intensity and increased with decreasing pH values. In the presence of Fe(2+), the degradation efficiency of diuron increased with increasing Fe(2+) concentration. The degradation efficiency of diuron was decreased during the first 4 min and increased during the last 10 min with adding of Cu(2+). Decreasing the initial conductivity and increasing the air flow rate were favorable for the degradation of diuron. Degradation of diuron by gas-liquid hybrid discharge fitted first-order kinetics. The pH value of the solution decreased during the reaction process. Total organic carbon removal rate increased in the presence of Fe(2+) or Cu(2+). The generated Cl(-1), NH(4)(+), NO(3)(-), oxalic acid, acetic acid and formic acid during the degradation process were also detected. Based on the detected Cl(-1) and other intermediates, a possible degradation pathway of diuron was proposed.

  18. Temperature Buffer Test. Final THM modelling

    International Nuclear Information System (INIS)

    Aakesson, Mattias; Malmberg, Daniel; Boergesson, Lennart; Hernelind, Jan; Ledesma, Alberto; Jacinto, Abel

    2012-01-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the final THM modelling which was resumed subsequent to the dismantling operation. The main part of this work has been numerical modelling of the field test. Three different modelling teams have presented several model cases for different geometries and different degree of process complexity. Two different numerical codes, Code B right and Abaqus, have been used. The modelling performed by UPC-Cimne using Code B right, has been divided in three subtasks: i) analysis of the response observed in the lower part of the test, by inclusion of a number of considerations: (a) the use of the Barcelona Expansive Model for MX-80 bentonite; (b) updated parameters in the vapour diffusive flow term; (c) the use of a non-conventional water retention curve for MX-80 at high temperature; ii) assessment of a possible relation between the cracks observed in the bentonite blocks in the upper part of TBT, and the cycles of suction and stresses registered in that zone at the start of the experiment; and iii) analysis of the performance, observations and interpretation of the entire test. It was however not possible to carry out a full THM analysis until the end of the test due to

  19. Temperature Buffer Test. Final THM modelling

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Malmberg, Daniel; Boergesson, Lennart; Hernelind, Jan [Clay Technology AB, Lund (Sweden); Ledesma, Alberto; Jacinto, Abel [UPC, Universitat Politecnica de Catalunya, Barcelona (Spain)

    2012-01-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the final THM modelling which was resumed subsequent to the dismantling operation. The main part of this work has been numerical modelling of the field test. Three different modelling teams have presented several model cases for different geometries and different degree of process complexity. Two different numerical codes, Code{sub B}right and Abaqus, have been used. The modelling performed by UPC-Cimne using Code{sub B}right, has been divided in three subtasks: i) analysis of the response observed in the lower part of the test, by inclusion of a number of considerations: (a) the use of the Barcelona Expansive Model for MX-80 bentonite; (b) updated parameters in the vapour diffusive flow term; (c) the use of a non-conventional water retention curve for MX-80 at high temperature; ii) assessment of a possible relation between the cracks observed in the bentonite blocks in the upper part of TBT, and the cycles of suction and stresses registered in that zone at the start of the experiment; and iii) analysis of the performance, observations and interpretation of the entire test. It was however not possible to carry out a full THM analysis until the end of the test due to

  20. Buffer layer annealing effects on the magnetization reversal process in Pd/Co/Pd systems

    International Nuclear Information System (INIS)

    Fassatoui, A.; Belhi, R.; Vogel, J.; Abdelmoula, K.

    2016-01-01

    We have investigated the effect of annealing the buffer layer on the magnetization reversal behavior in Pd/Co/Pd thin films using magneto-optical Kerr microscopy. It was found that annealing the buffer layer at 150 °C for 1 h decreases the coercivity and increases the saturation magnetization and the effective magnetic anisotropy constant. This study also shows that the annealing induces a change of the magnetization reversal from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation. This result demonstrates that the main effect of annealing the buffer layer is to decrease the domain wall pinning in the Co layer, favoring the domain wall propagation mode. - Highlights: • The buffer layer surface morphology changes upon annealing of the buffer layer. • The coercivity decreases while the saturation magnetization and the effective anisotropy increase with the annealing of the buffer layer. • The reversal process changes from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation when annealing the buffer layer.

  1. Buffer regulation of calcium puff sequences

    International Nuclear Information System (INIS)

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-01-01

    Puffs are localized Ca 2+ signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP 3 ). They are the result of the liberation of Ca 2+ from the endoplasmic reticulum through the coordinated opening of IP 3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca 2+ provides a mechanism that enriches the spatio–temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca 2+ signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP 3 R-Ca 2+ channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca 2+ buffer can increase the average number of channels that participate of a puff. (paper)

  2. Buffer regulation of calcium puff sequences.

    Science.gov (United States)

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-02-01

    Puffs are localized Ca(2 +) signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca(2 +) from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca(2 +) provides a mechanism that enriches the spatio-temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca(2 +) signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca(2 +) channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca(2 +) buffer can increase the average number of channels that participate of a puff.

  3. DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway.

    Science.gov (United States)

    Bai, Juli; Cervantes, Christopher; Liu, Juan; He, Sijia; Zhou, Haiyan; Zhang, Bilin; Cai, Huan; Yin, Dongqing; Hu, Derong; Li, Zhi; Chen, Hongzhi; Gao, Xiaoli; Wang, Fang; O'Connor, Jason C; Xu, Yong; Liu, Meilian; Dong, Lily Q; Liu, Feng

    2017-11-14

    Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the DNA-sensing cGAS-cGAMP-STING pathway. Fat-specific knockout of disulfide-bond A oxidoreductase-like protein (DsbA-L), a chaperone-like protein originally identified in the mitochondrial matrix, impaired mitochondrial function and promoted mtDNA release, leading to activation of the cGAS-cGAMP-STING pathway and inflammatory responses. Conversely, fat-specific overexpression of DsbA-L protected mice against high-fat diet-induced activation of the cGAS-cGAMP-STING pathway and inflammation. Taken together, we identify DsbA-L as a key molecule that maintains mitochondrial integrity. DsbA-L deficiency promotes inflammation and insulin resistance by activating the cGAS-cGAMP-STING pathway. Our study also reveals that, in addition to its well-characterized roles in innate immune surveillance, the cGAS-cGAMP-STING pathway plays an important role in mediating obesity-induced metabolic dysfunction.

  4. Laser-induced fluorescence spectra of Ba+*-He exciplexes produced in cold He gas

    International Nuclear Information System (INIS)

    Fukuyama, Yoshimitsu; Matsuo, Yukari; Moriwaki, Yoshiki

    2004-01-01

    We report the observation of laser-induced fluorescence spectra of Ba +* -He exciplexes. The experiment is carried out in an environment of cold gaseous helium at a temperature range of 3-30 K. We have observed the emission spectra of exciplexes by means of excitation of the 6p 2 P 32 2 S 12 transition of Ba + ions. It is found that these spectra are redshifted from the D2 emission line in the free space and are composed of several peaks. The experimental results are reproduced well by theoretical calculation of the emission spectra for vibrational levels of Ba +* -He. We also investigate the vibrational dynamics of the 6p 2 Π 32 state of Ba + *-He, and we have determined the collision-induced vibrational relaxation cross sections of the 6p 2 Π 32 state to be 9.7±1.1 A 2 at 15 K

  5. Current-induced spin polarization in a spin-polarized two-dimensional electron gas with spin-orbit coupling

    International Nuclear Information System (INIS)

    Wang, C.M.; Pang, M.Q.; Liu, S.Y.; Lei, X.L.

    2010-01-01

    The current-induced spin polarization (CISP) is investigated in a combined Rashba-Dresselhaus spin-orbit-coupled two-dimensional electron gas, subjected to a homogeneous out-of-plane magnetization. It is found that, in addition to the usual collision-related in-plane parts of CISP, there are two impurity-density-free contributions, arising from intrinsic and disorder-mediated mechanisms. The intrinsic parts of spin polarization are related to the Berry curvature, analogous with the anomalous and spin Hall effects. For short-range collision, the disorder-mediated spin polarizations completely cancel the intrinsic ones and the total in-plane components of CISP equal those for systems without magnetization. However, for remote disorders, this cancellation does not occur and the total in-plane components of CISP strongly depend on the spin-orbit interaction coefficients and magnetization for both pure Rashba and combined Rashba-Dresselhaus models.

  6. Electromagnetically induced transparency and ultraslow optical solitons in a coherent atomic gas filled in a slot waveguide.

    Science.gov (United States)

    Xu, Jin; Huang, Guoxiang

    2013-02-25

    We investigate the electromagnetically induced transparency (EIT) and nonlinear pulse propagation in a Λ-type three-level atomic gas filled in a slot waveguide, in which electric field is strongly confined inside the slot of the waveguide due to the discontinuity of dielectric constant. We find that EIT effect can be greatly enhanced due to the reduction of optical-field mode volume contributed by waveguide geometry. Comparing with the atomic gases in free space, the EIT transparency window in the slot waveguide system can be much wider and deeper, and the Kerr nonlinearity of probe laser field can be much stronger. We also prove that using slot waveguide ultraslow optical solitons can be produced efficiently with extremely low generation power.

  7. Unified first principles description from warm dense matter to ideal ionized gas plasma: electron-ion collisions induced friction.

    Science.gov (United States)

    Dai, Jiayu; Hou, Yong; Yuan, Jianmin

    2010-06-18

    Electron-ion interactions are central to numerous phenomena in the warm dense matter (WDM) regime and at higher temperature. The electron-ion collisions induced friction at high temperature is introduced in the procedure of ab initio molecular dynamics using the Langevin equation based on density functional theory. In this framework, as a test for Fe and H up to 1000 eV, the equation of state and the transition of electronic structures of the materials with very wide density and temperature can be described, which covers a full range of WDM up to high energy density physics. A unified first principles description from condensed matter to ideal ionized gas plasma is constructed.

  8. Hydrogen Gas Is Involved in Auxin-Induced Lateral Root Formation by Modulating Nitric Oxide Synthesis

    Directory of Open Access Journals (Sweden)

    Zeyu Cao

    2017-10-01

    Full Text Available Metabolism of molecular hydrogen (H2 in bacteria and algae has been widely studied, and it has attracted increasing attention in the context of animals and plants. However, the role of endogenous H2 in lateral root (LR formation is still unclear. Here, our results showed that H2-induced lateral root formation is a universal event. Naphthalene-1-acetic acid (NAA; the auxin analog was able to trigger endogenous H2 production in tomato seedlings, and a contrasting response was observed in the presence of N-1-naphthyphthalamic acid (NPA, an auxin transport inhibitor. NPA-triggered the inhibition of H2 production and thereafter lateral root development was rescued by exogenously applied H2. Detection of endogenous nitric oxide (NO by the specific probe 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM DA and electron paramagnetic resonance (EPR analyses revealed that the NO level was increased in both NAA- and H2-treated tomato seedlings. Furthermore, NO production and thereafter LR formation induced by auxin and H2 were prevented by 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO; a specific scavenger of NO and the inhibitor of nitrate reductase (NR; an important NO synthetic enzyme. Molecular evidence confirmed that some representative NO-targeted cell cycle regulatory genes were also induced by H2, but was impaired by the removal of endogenous NO. Genetic evidence suggested that in the presence of H2, Arabidopsis mutants nia2 (in particular and nia1 (two nitrate reductases (NR-defective mutants exhibited defects in lateral root length. Together, these results demonstrated that auxin-induced H2 production was associated with lateral root formation, at least partially via a NR-dependent NO synthesis.

  9. Electron induced formation and stability of molecular and cluster ions in gas phase and superfluid helium nanodroplets

    International Nuclear Information System (INIS)

    Aleem, M. A.

    2010-01-01

    The present PhD thesis represents a broad range study of electron induced formation and stability of positive and negative ions in gas phase and superfluid helium nanodroplets. The molecules studied are of industrial, environmental, plasma and biological relevance. The knowledge obtained from the study provides new insight for the proper understanding and control on energetics and dynamics of the reactions involved in the formation and fragmentation processes of the studied molecules and clusters. The experiments are accomplished and investigated using mass spectrometric techniques for the formation of molecular and cluster ions using different mass spectrometers available in our laboratory. One part of the work is focused on electron-induced reactions of the molecules in gas phase. Especially focus is laid to electron attachment to the isomers of mononitrotolouene used as an additive to explosives. The fragile nature and high internal energy of these molecules has lead to extensive fragmentation following the ionisation process. Dissociative electron attachment to the three different isomers has shown different resonances and therefore this process can be utilized to explicitly distinguish these isomers. Anion efficiency curves of the isomers have been studied using effusive molecular beam source in combination with a hemispherical electron monochromator as well as a Nier-type ion source attached to a sector field mass spectrometer. The outcome of the experiment is a reliable and effective detection method highly desirable for environmental and security reasons. Secondly, dissociative electron ionization of acetylene and propene is studied and their data is directly related to the plasma modelling for plasma fusion and processing reactors. Temperature effects for dissociative electron attachment to halo-hydrocarbons are also measured using a trochoidal electron monochromator. The second part of the work is concerned with the investigation of electron-induced

  10. Enantioselective Collision-Activated Dissociation of Gas-Phase Tryptophan Induced by Chiral Recognition of Protonated l-Alanine Peptides

    Science.gov (United States)

    Fujihara, Akimasa; Matsuyama, Hiroki; Tajiri, Michiko; Wada, Yoshinao; Hayakawa, Shigeo

    2017-06-01

    Enantioselective dissociation in the gas phase is important for enantiomeric enrichment and chiral transmission processes in molecular clouds regarding the origin of homochirality in biomolecules. Enantioselective collision-activated dissociation (CAD) of tryptophan (Trp) and the chiral recognition ability of l-alanine peptides ( l-Ala n ; n = 2-4) were examined using a linear ion trap mass spectrometer. CAD spectra of gas-phase heterochiral H+( d-Trp)( l-Ala n ) and homochiral H+( l-Trp)( l-Ala n ) noncovalent complexes were obtained as a function of the peptide size n. The H2O-elimination product was observed in CAD spectra of both heterochiral and homochiral complexes for n = 2 and 4, and in homochiral H+( l-Trp)( l-Ala3), indicating that the proton is attached to the l-alanine peptide, and H2O loss occurs from H+( l-Ala n ) in the noncovalent complexes. H2O loss did not occur in heterochiral H+( d-Trp)( l-Ala3), where NH3 loss and (H2O + CO) loss were the primary dissociation pathways. In heterochiral H+( d-Trp)( l-Ala3), the protonation site is the amino group of d-Trp, and NH3 loss and (H2O + CO) loss occur from H+( d-Trp). l-Ala peptides recognize d-Trp through protonation of the amino group for peptide size n = 3. NH3 loss and (H2O + CO) loss from H+( d-Trp) proceeds via enantioselective CAD in gas-phase heterochiral H+( d-Trp)( l-Ala3) at room temperature, whereas l-Trp dissociation was not observed in homochiral H+( l-Trp)( l-Ala3). These results suggest that enantioselective dissociation induced by chiral recognition of l-Ala peptides through protonation could play an important role in enantiomeric enrichment and chiral transmission processes of amino acids.

  11. In situ laser-induced breakdown spectroscopy measurements of chemical compositions in stainless steels during tungsten inert gas welding

    Science.gov (United States)

    Taparli, Ugur Alp; Jacobsen, Lars; Griesche, Axel; Michalik, Katarzyna; Mory, David; Kannengiesser, Thomas

    2018-01-01

    A laser-induced breakdown spectroscopy (LIBS) system was combined with a bead-on-plate Tungsten Inert Gas (TIG) welding process for the in situ measurement of chemical compositions in austenitic stainless steels during welding. Monitoring the weld pool's chemical composition allows governing the weld pool solidification behavior, and thus enables the reduction of susceptibility to weld defects. Conventional inspection methods for weld seams (e.g. ultrasonic inspection) cannot be performed during the welding process. The analysis system also allows in situ study of the correlation between the occurrence of weld defects and changes in the chemical composition in the weld pool or in the two-phase region where solid and liquid phase coexist. First experiments showed that both the shielding Ar gas and the welding arc plasma have a significant effect on the selected Cr II, Ni II and Mn II characteristic emissions, namely an artificial increase of intensity values via unspecific emission in the spectra. In situ investigations showed that this artificial intensity increase reached a maximum in presence of weld plume. Moreover, an explicit decay has been observed with the termination of the welding plume due to infrared radiation during sample cooling. Furthermore, LIBS can be used after welding to map element distribution. For austenitic stainless steels, Mn accumulations on both sides of the weld could be detected between the heat affected zone (HAZ) and the base material.

  12. A Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Induced Pseudoscalar Coupling gp

    International Nuclear Information System (INIS)

    Banks, Thomas Ira

    2007-01-01

    This dissertation describes a measurement of the rate of nuclear muon capture by the proton, performed by the MuCap Collaboration using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPa pressure. The hydrogen target's low gas density of 1 percent compared to liquid hydrogen is key to avoiding uncertainties that arise from the formation of muonic molecules. The capture rate was obtained from the difference between the mu- disappearance rate in hydrogen--as determined from data collected in the experiment's first physics run in fall2004--and the world average for the mu+ decay rate. After combining the results of my analysis with the results from another independent analysis of the 2004 data, the muon capture rate from the hyperfine singlet ground state of the mu-p atom is found to be Λ S = 725.0 ± 17.4 1/s, from which the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m2mu)= 7.3 ± 1.1, is extracted. This result for gP is consistent with theoretical predictions that are based on the approximate chiral symmetry of QCD

  13. Low noise buffer amplifiers and buffered phase comparators for precise time and frequency measurement and distribution

    Science.gov (United States)

    Eichinger, R. A.; Dachel, P.; Miller, W. H.; Ingold, J. S.

    1982-01-01

    Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators were developed. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state of the art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients.

  14. Fission gas induced fuel swelling in low and medium burnup fuel during high temperature transients

    International Nuclear Information System (INIS)

    Vinjamuri, K.

    1980-01-01

    The behavior of light water reactor fuel elements under postulated accident conditions is being studied by the EG and G Idaho, Inc., Thermal Fuels Behavior Program for the Nuclear Regulatory Commission. As a part of this program, unirradiated and previously irradiated, pressurized-water-reactor type fuel rods were tested under power-cooling-mismatch (PCM) conditions in the Power Burst Facility (PBF). During these integral in-reactor experiments, film boiling was produced on the fuel rods which created high fuel and cladding temperatures. Fuel rod diameters increased in the film boiling region to a greater extent for irradiated rods than for unirradiated rods. The purpose of the study was to investigate and assess the fuel swelling which caused the fuel rod diameter increases and to evaluate the ability of an analytical code, the Gas Release and Swelling Subroutine - Steady-State and Transient (GRASS-SST), to predict the results

  15. Fission gas induced fuel swelling in low and medium burnup fuel during high temperature transients. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Vinjamuri, K.

    1980-01-01

    The behavior of light water reactor fuel elements under postulated accident conditions is being studied by the EG and G Idaho, Inc., Thermal Fuels Behavior Program for the Nuclear Regulatory Commission. As a part of this program, unirradiated and previously irradiated, pressurized-water-reactor type fuel rods were tested under power-cooling-mismatch (PCM) conditions in the Power Burst Facility (PBF). During these integral in-reactor experiments, film boiling was produced on the fuel rods which created high fuel and cladding temperatures. Fuel rod diameters increased in the film boiling region to a greater extent for irradiated rods than for unirradiated rods. The purpose of the study was to investigate and assess the fuel swelling which caused the fuel rod diameter increases and to evaluate the ability of an analytical code, the Gas Release and Swelling Subroutine - Steady-State and Transient (GRASS-SST), to predict the results.

  16. Quantum pump effect induced by a linearly polarized microwave in a two-dimensional electron gas.

    Science.gov (United States)

    Song, Juntao; Liu, Haiwen; Jiang, Hua

    2012-05-30

    A quantum pump effect is predicted in an ideal homogeneous two-dimensional electron gas (2DEG) that is normally irradiated by linearly polarized microwaves (MW). Without considering effects from spin-orbital coupling or the magnetic field, it is found that a polarized MW can continuously pump electrons from the longitudinal to the transverse direction, or from the transverse to the longitudinal direction, in the central irradiated region. The large pump current is obtained for both the low frequency limit and the high frequency case. Its magnitude depends on sample properties such as the size of the radiated region, the power and frequency of the MW, etc. Through the calculated results, the pump current should be attributed to the dominant photon-assisted tunneling processes as well as the asymmetry of the electron density of states with respect to the Fermi energy.

  17. Effect of simultaneously induced environmental stimuli on electrical signalling and gas exchange in maize plants.

    Science.gov (United States)

    Vuralhan-Eckert, Jasmin; Lautner, Silke; Fromm, Jörg

    2018-04-01

    Electrical signalling in response to environmental stimuli is a well-known phenomenon in higher plants. For example, in maize, different stimuli, such as wounding or re-irrigation after drought, incite characteristic electrical signals which have quite particular effects on gas exchange. What is less well understood is how plants (specifically maize) respond when two different environmental stimuli are applied simultaneously. To explore this, a three-stage experiment was designed. In the first stage, drought conditions were simulated by decreasing the soil water content to 30-40 % of field capacity. In these conditions, and in contrast to well-watered plants, the maize exhibited only 60-70% of the original level of stomatal conductance and 50-60 % of the original photosynthesis rate. In the second stage of the experiment the plants were re-irrigated and heat stimulated separately. Re-irrigation led to specific electrical signals followed by a gradual increase of gas exchange. In contrast, after heat stimulation of a leaf an electrical signal was evoked that reduced the net CO 2 -uptake rate as well as stomatal conductance. In the third stage, to elucidate how plants process simultaneous re-irrigation and heat stimulation, the drought-stressed maize plants were re-watered and heat-stimulated at the same time. Results showed a two phase response. In the first phase there was a rapid decrease in both the CO 2 uptake rate and the stomatal conductance, while in the second phase each of these parameters increased gradually. Thus, the results strongly support the view that the responses from both stimuli were combined, indicating that maize plants can process simultaneously applied stimuli. Copyright © 2018 Elsevier GmbH. All rights reserved.

  18. Buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions: from protein buffer capacity prediction to bioprocess applications.

    Science.gov (United States)

    Bahrenburg, Sven; Karow, Anne R; Garidel, Patrick

    2015-04-01

    Protein therapeutics, including monoclonal antibodies (mAbs), have significant buffering capacity, particularly at concentrations>50 mg/mL. This report addresses pH-related issues critical to adoption of self-buffered monoclonal antibody formulations. We evaluated solution conditions with protein concentrations ranging from 50 to 250 mg/mL. Samples were both buffer-free and conventionally buffered with citrate. Samples were non-isotonic or adjusted for isotonicity with NaCl or trehalose. Studies included accelerated temperature stability tests, shaking stability studies, and pH changes in infusion media as protein concentrate is added. We present averaged buffering slopes of capacity that can be applied to any mAb and present a general method for calculating buffering capacity of buffer-free, highly concentrated antibody liquid formulations. In temperature stability tests, neither buffer-free nor conventionally buffered solution conditions showed significant pH changes. Conventionally buffered solutions showed significantly higher opalescence than buffer-free ones. In general, buffer-free solution conditions showed less aggregation than conventionally buffered solutions. Shaking stability tests showed no differences between buffer-free and conventionally buffered solutions. "In-use" preparation experiments showed that pH in infusion bag medium can rapidly approximate that of self-buffered protein concentrate as concentrate is added. In summary, the buffer capacity of proteins can be predicted and buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Similarity of salt influences on the pH of buffers, polyelectrolytes, and proteins.

    Science.gov (United States)

    Voinescu, Alina E; Bauduin, Pierre; Pinna, M Cristina; Touraud, Didier; Ninham, Barry W; Kunz, Werner

    2006-05-04

    Changes in pH induced by the addition of electrolytes to buffers, polyelectrolytes (a polycarboxy polymethylene and a polyethyleneimine), and proteins (casein, whey, and lysozyme) solutions are explored systematically. The two buffer systems are triethanolamine/triethanolammonium chloride and citric acid/sodium citrate. These are chosen because of the similarity of their acid-base equilibria with those of amino acids predominant in most proteins, that is, amino acids that include carboxylate or ammonium groups in their structures. The pH of triethanolamine and of citrate buffers respectively increases and decreases when salt is added. At low electrolyte concentrations (buffer solutions. It is even possible to qualitatively predict these changes in protein solutions simply from the primary protein structure. At least in the systems considered here, the specific ion effects on pH seem to correlate with the bulk activity coefficients of the added electrolytes, at least at moderate salt concentrations.

  20. Static mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Suzuki, Hideaki

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of unconfined compression tests, one-dimensional consolidation tests, consolidated-undrained triaxial compression tests and consolidated-undrained triaxial creep tests that aim at getting hold of static mechanical properties. We can get hold of the relationship between the dry density and tensile stress etc. by Brazilian tests, between the dry density and unconfined compressive strength etc. by unconfined compression tests, between the consolidation stress and void ratio etc. by one-dimensional consolidation tests, the stress pass of each effective confining pressure etc. by consolidated-undrained triaxial compression tests and the axial strain rate with time of each axial stress etc. by consolidated-undrained triaxial creep tests. (author)

  1. Sustained housing-type social buffering following social housing in male rats.

    Science.gov (United States)

    Kiyokawa, Yasushi; Ishida, Aya; Takeuchi, Yukari; Mori, Yuji

    2016-05-01

    In social animals, recovery from the adverse effects of distressing stimuli is promoted by subsequent cohousing with a conspecific animal(s). This phenomenon has been termed housing-type social buffering. We previously found that social housing induced housing-type social buffering in fear-conditioned male rats. This buffering took the form of attenuated conditioned hyperthermia in response to an auditory conditioned stimulus (CS). Here, we assessed whether this social buffering is sustained even if the subject is housed alone after a period of social housing. When fear-conditioned subjects were housed alone during a 48-h period between conditioning and re-exposure to the auditory CS, they exhibited conditioned hyperthermia in response to the CS. However, conditioned hyperthermia was not observed when the 12-h period of social housing began 24 and 36h after conditioning during the 48-h period. This was not the case when the 12-h period of social housing began 0 and 12h after the conditioning. These results suggest that housing-type social buffering is sustained for 12h after the 12-h period of social housing. We next considered whether increasing the duration of social housing would extend the period of social buffering. We observed social buffering of conditioned hyperthermia 24 and 48, but not 96h after a 24-h period of social housing. These results suggest that social buffering was extended when the duration of social housing was increased. Taken together, our findings indicate that housing-type social buffering is sustained after a period of social housing. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Laser-induced gratings in the gas phase excited via Raman-active transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, D N [General Physics Inst., Russian Academy of Sciences, Moscow (Russian Federation); Bombach, R; Hemmerling, B; Hubschmid, W [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We report on a new time resolved coherent Raman technique that is based on the generation of thermal gratings following a population change among molecular levels induced by stimulated Raman pumping. This is achieved by spatially and temporally overlapping intensity interference patterns generated independently by two lasers. When this technique is used in carbon dioxide, employing transitions which belong to the Q-branches of the {nu}{sub 1}/2{nu}{sub 2} Fermi dyad, it is possible to investigate molecular energy transfer processes. (author) 2 figs., 10 refs.

  3. Temperature Buffer Test. Measurements of water content and density of the excavated buffer material

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Lars-Erik [Clay Technology AB, Lund (Sweden)

    2010-12-15

    TBT (Temperature Buffer Test) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at understanding and modeling the thermo-hydromechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test was carried out at the - 420 m level in Aespoe HRL in a 8 meters deep and 1.76 m diameter deposition hole, with two heaters (3 m long, 0.6 m diameter), surrounded by a MX-80 bentonite buffer and a confining plug on top anchored with 9 rods. It was installed during spring 2003. The bentonite around upper heater was removed during the period October - December 2009 and the buffer around the lower heater was removed during January - Mars 2010. During dismantling of the buffer, samples were taken on which analyses were made. This report describes the work with the deteroemoeination of the water content and the density of the taken samples. Most of the samples were taken from the buffer by core drilling from the upper surface of each installed bentonite block. The cores had a diameter of about 50 mm and a maximum length equal to the original height of the bentonite blocks (about 500 mm). The water content of the buffer was determined by drying a sample at a temperature of 105 deg C for 24 h and the bulk density was determined by weighing a sample both in the air and immerged in paraffin oil with known density. The water content, dry density, degree of saturation and void ratio of the buffer were then plotted. The plots show that all parts of the buffer had taken up water and the degree of saturation of the buffer varied between 90 - 100%. Large variation in the dry density of the buffer was also observed.

  4. Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

    International Nuclear Information System (INIS)

    Gounder, J.D.; Kutne, P.; Meier, W.

    2012-01-01

    The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 °C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 °C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled laboratory

  5. Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Gounder, J.D., E-mail: James.Gounder@dlr.de; Kutne, P.; Meier, W.

    2012-08-15

    The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 Degree-Sign C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 Degree-Sign C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled

  6. Experimental and theoretical study of the electron cascade induced in a gas by laser light

    International Nuclear Information System (INIS)

    Louis-Jacquet, Michel.

    1978-10-01

    In a laser gas interaction experiment, first electrons created by multiphoton ionization of atoms gain sufficient energy in the laser E.M. wave to promote collisional ionization of other atoms. An experimental and theoretical study of the electron-neutral atom inverse bremsstrahlung process and the consecutive electron cascade is presented. The main basic idea is to create an initial electron population and to study its evolution versus the photon density. A Boltzman equation including several collision terms can describe such a plasma. The resolution by a general eigen values method shows that the electron density growth rate is inversely proportionnal to both neutral atom density and laser light illumination. Experimental conditions were defined in order to insure negligible secondary mechanisms (multiphoton ionization, diffusion, recombination, ...). Using a macroscopic description of the interaction, the growth rate can be deduced from the experimental results. Values are in a rather good agreement with the theoretical ones. Moreover evidence is given of influence of the excited atoms on the multiplication process [fr

  7. Carbon-14 labelling of biomolecules induced by 14CO ionized gas

    International Nuclear Information System (INIS)

    Lier, J.E. van; Sanche, L.

    1979-01-01

    Ionized 14 CO gas provides a rapid method for producing 14 C-labelled biomolecules. The apparatus consists of a high vacuum system in which a small amount of 14 CO is ionized by electron impact. The resulting species drift towards a target where they interact with the molecule of interest to produce 14 C-labelled compounds. Since the reaction time is only 2 minutes, the method is particularly promising for producing tracer biomolecules with short-lived 11 C at high specific activities. The applicability of the method to various classes of compounds of biological importance, including steroids, alkaloids, prostaglandins, nucleosides, amino acids and proteins has been studied. All compounds treated gave rise to 14 C addition and degradation products. Furthermore, for some compounds, chromatographic analysis in multiple systems followed by derivatization and crystallization to constant specific activity, indicated that carbon exchange may occur to produce the labelled, but otherwise unaltered substrate in yields of the order of 10-100 mCi/mol. More conclusive proof of radiochemical identity must await production of larger quantities of material and rigorous purification including at least two different chromatographic techniques. (author)

  8. Scientific Applications Performance Evaluation on Burst Buffer

    KAUST Repository

    Markomanolis, George S.

    2017-10-19

    Parallel I/O is an integral component of modern high performance computing, especially in storing and processing very large datasets, such as the case of seismic imaging, CFD, combustion and weather modeling. The storage hierarchy includes nowadays additional layers, the latest being the usage of SSD-based storage as a Burst Buffer for I/O acceleration. We present an in-depth analysis on how to use Burst Buffer for specific cases and how the internal MPI I/O aggregators operate according to the options that the user provides during his job submission. We analyze the performance of a range of I/O intensive scientific applications, at various scales on a large installation of Lustre parallel file system compared to an SSD-based Burst Buffer. Our results show a performance improvement over Lustre when using Burst Buffer. Moreover, we show results from a data hierarchy library which indicate that the standard I/O approaches are not enough to get the expected performance from this technology. The performance gain on the total execution time of the studied applications is between 1.16 and 3 times compared to Lustre. One of the test cases achieved an impressive I/O throughput of 900 GB/s on Burst Buffer.

  9. Improved indexes for targeting placement of buffers of Hortonian runoff

    Science.gov (United States)

    M.G. Dosskey; Z. Qiu; M.J. Helmers; D.E. Eisenhauer

    2011-01-01

    Targeting specific locations within agricultural watersheds for installing vegetative buffers has been advocated as a way to enhance the impact of buffers and buffer programs on stream water quality. Existing models for targeting buffers of Hortonian, or infiltration-excess, runoff are not well developed. The objective was to improve on an existing soil survey–based...

  10. A buffer overflow detection based on inequalities solution

    International Nuclear Information System (INIS)

    Xu Guoai; Zhang Miao; Yang Yixian

    2007-01-01

    A new buffer overflow detection model based on Inequalities Solution was designed, which is based on analyzing disadvantage of the old buffer overflow detection technique and successfully converting buffer overflow detection to Inequalities Solution. The new model can conquer the disadvantage of the old technique and improve efficiency of buffer overflow detection. (authors)

  11. Positive pressure ventilation with the open lung concept optimizes gas exchange and reduces ventilator-induced lung injury in newborn piglets

    NARCIS (Netherlands)

    van Kaam, Anton H.; de Jaegere, Anne; Haitsma, Jack J.; van Aalderen, Wim M.; Kok, Joke H.; Lachmann, Burkhard

    2003-01-01

    Previous studies demonstrated that high-frequency oscillatory ventilation using the open lung concept (OLC resulted in superior gas exchange and a reduction in ventilator-induced lung injury (VILI). We hypothesized that these beneficial effects could also be achieved by applying the OLC during

  12. Production of simplex RNS and ROS by nanosecond pulse N2/O2 plasma jets with homogeneous shielding gas for inducing myeloma cell apoptosis

    Science.gov (United States)

    Liu, Zhijie; Xu, Dehui; Liu, Dingxin; Cui, Qingjie; Cai, Haifeng; Li, Qiaosong; Chen, Hailan; Kong, Michael G.

    2017-05-01

    In this paper, atmospheric pressure N2/O2 plasma jets with homogeneous shielding gas excited by nanosecond pulse are obtained to generate simplex reactive nitrogen species (RNS) and reactive oxygen species (ROS), respectively, for the purpose of studying the simplex RNS and ROS to induce the myeloma cell apoptosis with the same discharge power. The results reveal that the cell death rate by the N2 plasma jet with N2 shielding gas is about two times that of the O2 plasma jet with O2 shielding gas for the equivalent treatment time. By diagnosing the reactive species of ONOO-, H2O2, OH and \\text{O}2- in medium, our findings suggest the cell death rate after plasma jets treatment has a positive correlation with the concentration of ONOO-. Therefore, the ONOO- in medium is thought to play an important role in the process of inducing myeloma cell apoptosis.

  13. Moisture buffer capacity of different insulation materials

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

    2004-01-01

    . In the isothermal tests the material samples were exposed to the same change in the relative humidity of the ambient air on both sides, while the samples were exposed to variations in relative humidity only on the cold side in the non-isothermal tests. The results of these rather different measurement principles...... lead to more durable constructions. In this paper, a large range of very different thermal insulation materials have been tested in specially constructed laboratory facilities to determine their moisture buffer capacity. Both isothermal and nonisothermal experimental set-ups have been used...... are discussed, and different ways are presented how to determine the moisture buffer capacity of the materials using partly standard material parameters and partly parameters determined from the actual measurements. The results so far show that the determination of moisture buffer capacity is very sensitive...

  14. Buffer construction technique using granular bentonite

    International Nuclear Information System (INIS)

    Masuda, Ryoichi; Asano, Hidekazu; Toguri, Satohito; Mori, Takuo; Shimura, Tomoyuki; Matsuda, Takeshi; Uyama, Masao; Noda, Masaru

    2007-01-01

    Buffer construction using bentonite pellets as filling material is a promising technology for enhancing the ease of repository operation. In this study, a test of such technology was conducted in a full-scale simulated disposal drift, using a filling system which utilizes a screw conveyor system. The simulated drift, which contained two dummy overpacks, was configured as a half-cross-section model with a height of 2.22 m and a length of 6.0 m. The average dry density of the buffer obtained in the test was 1.29 Mg/m 3 , with an angle of repose of 35 to 40 degrees. These test results indicate that buffer construction using a screw conveyor system for pellet emplacement in a waste disposal drift is a promising technology for repositories for high level radioactive wastes. (author)

  15. Labview virtual instruments for calcium buffer calculations.

    Science.gov (United States)

    Reitz, Frederick B; Pollack, Gerald H

    2003-01-01

    Labview VIs based upon the calculator programs of Fabiato and Fabiato (J. Physiol. Paris 75 (1979) 463) are presented. The VIs comprise the necessary computations for the accurate preparation of multiple-metal buffers, for the back-calculation of buffer composition given known free metal concentrations and stability constants used, for the determination of free concentrations from a given buffer composition, and for the determination of apparent stability constants from absolute constants. As implemented, the VIs can concurrently account for up to three divalent metals, two monovalent metals and four ligands thereof, and the modular design of the VIs facilitates further extension of their capacity. As Labview VIs are inherently graphical, these VIs may serve as useful templates for those wishing to adapt this software to other platforms.

  16. Developing suitable buffers to capture transport cycling behavior

    DEFF Research Database (Denmark)

    Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum

    2014-01-01

    units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7 days form the basis for the development and testing of different neighborhood...... buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show...... center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior....

  17. Buffer of Events as a Markovian Process

    International Nuclear Information System (INIS)

    Berdugo, J.; Casaus, J.; Mana, C.

    2001-01-01

    In Particle and Asro-Particle Physics experiments, the events which get trough the detectors are read and processes on-line before they are stored for a more detailed processing and future Physics analysis. Since the events are read and, usually, processed sequentially, the time involved in these operations can lead to a significant lose of events which is, to some extent, reduced by using buffers. We present an estimate of the optimum buffer size and the fraction of events lost for a simple experimental condition which serves as an introductory example to the use of Markow Chains.(Author)

  18. Buffer of Events as a Markovian Process

    Energy Technology Data Exchange (ETDEWEB)

    Berdugo, J.; Casaus, J.; Mana, C.

    2001-07-01

    In Particle and Asro-Particle Physics experiments, the events which get trough the detectors are read and processes on-line before they are stored for a more detailed processing and future Physics analysis. Since the events are read and, usually, processed sequentially, the time involved in these operations can lead to a significant lose of events which is, to some extent, reduced by using buffers. We present an estimate of the optimum buffer size and the fraction of events lost for a simple experimental condition which serves as an introductory example to the use of Markow Chains.(Author)

  19. Emplacement of small and large buffer blocks

    International Nuclear Information System (INIS)

    Saari, H.; Nikula, M.; Suikki, M.

    2010-05-01

    The report describes emplacement of a buffer structure encircling a spent fuel canister to be deposited in a vertical hole. The report deals with installability of various size blocks and with an emplacement gear, as well as evaluates the achieved quality of emplacement and the time needed for installing the buffer. Two block assembly of unequal size were chosen for examination. A first option involved small blocks, the use of which resulted in a buffer structure consisting of small sector blocks 200 mm in height. A second option involved large blocks, resulting in a buffer structure which consists of eight blocks. In these tests, the material chosen for both block options was concrete instead of bentonite. The emplacement test was a three-phase process. A first phase included stacking a two meter high buffer structure with small blocks for ensuring the operation of test equipment and blocks. A second phase included installing buffer structures with both block options to a height matching that of a canister-encircling cylindrical component. A third phase included testing also the installability of blocks to be placed above the canister by using small blocks. In emplacement tests, special attention was paid to the installability of blocks as well as to the time required for emplacement. Lifters for both blocks worked well. Due to the mass to be lifted, the lifter for large blocks had a more heavy-duty frame structure (and other lifting gear). The employed lifters were suspended in the tests on a single steel wire rope. Stacking was managed with both block sizes at adequate precision and stacked-up towers were steady. The stacking of large blocks was considerably faster. Therefore it is probably that the overall handling of the large blocks will be more convenient at a final disposal site. From the standpoint of reliability in lifting, the small blocks were safer to install above the canister. In large blocks, there are strict shape-related requirements which are

  20. Measurement of OH free radical in magnetized sheet plasma crossed with vertical gas-flow by laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Tonegawa, Akira; Takatori, Masahiko; Kobayashi, Yukihiro; Kawamura, Kazutaka; Takayama, Kazuo

    1997-01-01

    We demonstrated the production of OH free radicals in an argon magnetized sheet plasma crossed with vertical gas-flow mixed with an oxygen gas O 2 and a hydrogen gas H 2 . The density and the rotational-vibrational temperature of the OH free radicals were measured by a laser-induced fluorescence (LIF). The density of OH free radicals increases with increasing O 2 gas-flow, while the high energy part of the electron-energy-distribution-function f e (E) above 8 eV decreases. These results suggest the high energy part of f e (E) is contributed to the dissociation of O 2 and the production of OH free radicals. (author)

  1. Photo-Induced Room-Temperature Gas Sensing with a-IGZO Based Thin-Film Transistors Fabricated on Flexible Plastic Foil.

    Science.gov (United States)

    Knobelspies, Stefan; Bierer, Benedikt; Daus, Alwin; Takabayashi, Alain; Salvatore, Giovanni Antonio; Cantarella, Giuseppe; Ortiz Perez, Alvaro; Wöllenstein, Jürgen; Palzer, Stefan; Tröster, Gerhard

    2018-01-26

    We present a gas sensitive thin-film transistor (TFT) based on an amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) semiconductor as the sensing layer, which is fabricated on a free-standing flexible polyimide foil. The photo-induced sensor response to NO₂ gas at room temperature and the cross-sensitivity to humidity are investigated. We combine the advantages of a transistor based sensor with flexible electronics technology to demonstrate the first flexible a-IGZO based gas sensitive TFT. Since flexible plastic substrates prohibit the use of high operating temperatures, the charge generation is promoted with the help of UV-light absorption, which ultimately triggers the reversible chemical reaction with the trace gas. Furthermore, the device fabrication process flow can be directly implemented in standard TFT technology, allowing for the parallel integration of the sensor and analog or logical circuits.

  2. Photo-Induced Room-Temperature Gas Sensing with a-IGZO Based Thin-Film Transistors Fabricated on Flexible Plastic Foil

    Directory of Open Access Journals (Sweden)

    Stefan Knobelspies

    2018-01-01

    Full Text Available We present a gas sensitive thin-film transistor (TFT based on an amorphous Indium–Gallium–Zinc–Oxide (a-IGZO semiconductor as the sensing layer, which is fabricated on a free-standing flexible polyimide foil. The photo-induced sensor response to NO2 gas at room temperature and the cross-sensitivity to humidity are investigated. We combine the advantages of a transistor based sensor with flexible electronics technology to demonstrate the first flexible a-IGZO based gas sensitive TFT. Since flexible plastic substrates prohibit the use of high operating temperatures, the charge generation is promoted with the help of UV-light absorption, which ultimately triggers the reversible chemical reaction with the trace gas. Furthermore, the device fabrication process flow can be directly implemented in standard TFT technology, allowing for the parallel integration of the sensor and analog or logical circuits.

  3. A comparison of single knock-on and complete bubble destruction models of the fission induced re-solution of gas atoms from bubbles

    International Nuclear Information System (INIS)

    Wood, M.H.

    1978-03-01

    In previous theoretical studies of the behaviour of the fission gases in nuclear fuel, the Nelson single knock-on model of the fission induced re-solution of gas atoms from fission gas bubbles has been employed. In the present investigation, predictions from this model are compared with those from a complete bubble destruction model of the re-solution process. The main conclusions of the study are that the complete bubble destruction model predicts more gas release after a particular irradiation time than the single knock-on model, for the same choice of the model parameters, and that parameter sets chosen to give the same gas release predict significantly different bubble size distribution functions. (author)

  4. Grass buffers for playas in agricultural landscapes: An annotated bibliography

    Science.gov (United States)

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    This bibliography and associated literature synthesis (Melcher and Skagen, 2005) was developed for the Playa Lakes Joint Venture (PLJV). The PLJV sought compilation and annotation of the literature on grass buffers for protecting playas from runoff containing sediments, nutrients, pesticides, and other contaminants. In addition, PLJV sought information regarding the extent to which buffers may attenuate the precipitation runoff needed to fill playas, and avian use of buffers. We emphasize grass buffers, but we also provide information on other buffer types.

  5. Gas chromatography/chemical ionization triple quadrupole mass spectrometry analysis of anabolic steroids: ionization and collision-induced dissociation behavior.

    Science.gov (United States)

    Polet, Michael; Van Gansbeke, Wim; Van Eenoo, Peter; Deventer, Koen

    2016-02-28

    The detection of new anabolic steroid metabolites and new designer steroids is a challenging task in doping analysis. Switching from electron ionization gas chromatography triple quadrupole mass spectrometry (GC/EI-MS/MS) to chemical ionization (CI) has proven to be an efficient way to increase the sensitivity of GC/MS/MS analyses and facilitate the detection of anabolic steroids. CI also extends the possibilities of GC/MS/MS analyses as the molecular ion is retained in its protonated form due to the softer ionization. In EI it can be difficult to find previously unknown but expected metabolites due to the low abundance or absence of the molecular ion and the extensive (and to a large extent unpredictable) fragmentation. The main aim of this work was to study the CI and collision-induced dissociation (CID) behavior of a large number of anabolic androgenic steroids (AAS) as their trimethylsilyl derivatives in order to determine correlations between structures and CID fragmentation. Clarification of these correlations is needed for the elucidation of structures of unknown steroids and new metabolites. The ionization and CID behavior of 65 AAS have been studied using GC/CI-MS/MS with ammonia as the reagent gas. Glucuronidated AAS reference standards were first hydrolyzed to obtain their free forms. Afterwards, all the standards were derivatized to their trimethylsilyl forms. Full scan and product ion scan analyses were used to examine the ionization and CID behavior. Full scan and product ion scan analyses revealed clear correlations between AAS structure and the obtained mass spectra. These correlations were confirmed by analysis of multiple hydroxylated, methylated, chlorinated and deuterated analogs. AAS have been divided into three groups according to their ionization behavior and into seven groups according to their CID behavior. Correlations between fragmentation and structure were revealed and fragmentation pathways were postulated. Copyright © 2016 John Wiley

  6. Cosmic Rays and Non-thermal Emission Induced by Accretion of Cool Gas onto the Galactic Disk

    Science.gov (United States)

    Inoue, Susumu; Uchiyama, Yasunobu; Arakawa, Masanori; Renaud, Matthieu; Wada, Keiichi

    2017-11-01

    On both observational and theoretical grounds, the disk of our Galaxy should be accreting cool gas with temperature ≲ {10}5 K via the halo at a rate ˜1 {{M}⊙ {yr}}-1. At least some of this accretion is mediated by high-velocity clouds (HVCs), observed to be traveling in the halo with velocities of a few 100 km s-1 and occasionally impacting the disk at such velocities, especially in the outer regions of the Galaxy. We address the possibility of particle acceleration in shocks triggered by such HVC accretion events, and the detectability of consequent non-thermal emission in the radio to gamma-ray bands and high-energy neutrinos. For plausible shock velocities ˜ 300 {km} {{{s}}}-1 and magnetic field strengths ˜ 0.3{--}10 μ {{G}}, electrons and protons may be accelerated up to ˜1-10 TeV and ˜ 30{--}{10}3 TeV, respectively, in sufficiently strong adiabatic shocks during their lifetime of ˜ {10}6 {{yr}}. The resultant pion decay and inverse Compton gamma-rays may be the origin of some unidentified Galactic GeV-TeV sources, particularly the “dark” source HESS J1503-582 that is spatially coincident with the anomalous H I structure known as “forbidden-velocity wings.” Correlation of their locations with star-forming regions may be weak, absent, or even opposite. Non-thermal radio and X-ray emission from primary and/or secondary electrons may be detectable with deeper observations. The contribution of HVC accretion to Galactic cosmic rays is subdominant, but could be non-negligible in the outer Galaxy. As the thermal emission induced by HVC accretion is likely difficult to detect, observations of such phenomena may offer a unique perspective on probing gas accretion onto the Milky Way and other galaxies.

  7. Measurement of IL-13–Induced iNOS-Derived Gas Phase Nitric Oxide in Human Bronchial Epithelial Cells

    Science.gov (United States)

    Suresh, Vinod; Mih, Justin D.; George, Steven C.

    2007-01-01

    Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl·s−1.cm−2) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air–liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 ± 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13–stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS. PMID:17347445

  8. Measurement of IL-13-induced iNOS-derived gas phase nitric oxide in human bronchial epithelial cells.

    Science.gov (United States)

    Suresh, Vinod; Mih, Justin D; George, Steven C

    2007-07-01

    Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl.s(-1.)cm(-2)) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air-liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 +/- 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13-stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS.

  9. ssDNA degradation along capillary electrophoresis process using a Tris buffer.

    Science.gov (United States)

    Ric, Audrey; Ong-Meang, Varravaddheay; Poinsot, Verena; Martins-Froment, Nathalie; Chauvet, Fabien; Boutonnet, Audrey; Ginot, Frédéric; Ecochard, Vincent; Paquereau, Laurent; Couderc, François

    2017-06-01

    Tris-Acetate buffer is currently used in the selection and the characterization of ssDNA by capillary electrophoresis (CE). By applying high voltage, the migration of ionic species into the capillary generates a current that induces water electrolysis. This phenomenon is followed by the modification of the pH and the production of Tris derivatives. By injecting ten times by capillary electrophoresis ssDNA (50 nM), the whole oligonucleotide was degraded. In this paper, we will show that the Tris buffer in the running vials is modified along the electrophoretic process by electrochemical reactions. We also observed that the composition of the metal ions changes in the running buffer vials. This phenomenon, never described in CE, is important for fluorescent ssDNA analysis using Tris buffer. The oligonucleotides are degraded by electrochemically synthesized species (present in the running Tris vials) until it disappears, even if the separation buffer in the capillary is clean. To address these issues, we propose to use a sodium phosphate buffer that we demonstrate to be electrochemically inactive. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The buffer effect in neutral electrolyte supercapacitors

    DEFF Research Database (Denmark)

    Thrane Vindt, Steffen; Skou, Eivind M.

    2016-01-01

    The observation that double-layer capacitors based on neutral aqueous electrolytes can have significantly wider usable potential windows than those based on acidic or alkaline electrolytes is studied. This effect is explained by a local pH change taking place at the electrode surfaces, leading...... potassium nitrate as the electrolyte and potassium phosphates as the buffer system....

  11. Buffer Overflow Period in a MAP Queue

    Directory of Open Access Journals (Sweden)

    Andrzej Chydzinski

    2007-01-01

    Full Text Available The buffer overflow period in a queue with Markovian arrival process (MAP and general service time distribution is investigated. The results include distribution of the overflow period in transient and stationary regimes and the distribution of the number of cells lost during the overflow interval. All theorems are illustrated via numerical calculations.

  12. Body Buffer Zone and Proxemics in Blocking.

    Science.gov (United States)

    Stockwell, John C.; Bahs, Clarence W.

    This paper investigates the effect of personal body buffer zones on compositional arrangements staged by novice directors. Relationships between directors' concepts of personal space and their projection of its dimensions into staging are studied through the use of a variety of proximity measures--distance, area angles of approach, and physical…

  13. Direct measurement of the concentration of metastable ions produced from neutral gas particles using laser-induced fluorescence

    Science.gov (United States)

    Chu, Feng; Skiff, Fred; Berumen, Jorge; Mattingly, Sean; Hood, Ryan

    2017-10-01

    Extensive information can be obtained on wave-particle interactions and wave fields by direct measurement of perturbed ion distribution functions using laser-induced fluorescence (LIF). For practical purposes, LIF is frequently performed on metastables that are produced from neutral gas particles and existing ions in other electronic states. We numerically simulate the ion velocity distribution measurement and wave-detection process using a Lagrangian model for the LIF signal. The results show that under circumstances where the metastable ion population is coming directly from the ionization of neutrals (as opposed to the excitation of ground-state ions), the velocity distribution will only faithfully represent processes which act on the ion dynamics in a time shorter than the metastable lifetime. Therefore, it is important to know the ratio of metastable population coming from neutrals to that from existing ions to correct the LIF measurements of plasma ion temperature and electrostatic waves. In this paper, we experimentally investigate the ratio of these two populations by externally launching an ion acoustic wave and comparing the wave amplitudes that are measured with LIF and a Langmuir probe using a lock-in amplifier. DE-FG02-99ER54543.

  14. Analyte induced water adsorbability in gas phase biosensors: the influence of ethinylestradiol on the water binding protein capacity.

    Science.gov (United States)

    Snopok, Borys; Kruglenko, Ivanna

    2015-05-07

    An ultra-sensitive gas phase biosensor/tracer/bio-sniffer is an emerging technology platform designed to provide real-time information on air-borne analytes, or those in liquids, through classical headspace analysis. The desired bio-sniffer measures gaseous 17α- ethinylestradiol (ETED) as frequency changes on a quartz crystal microbalance (QCM), which is a result of the interactions of liquid sample components in the headspace (ETED and water) with a biorecognition layer. The latter was constructed by immobilization of polyclonal antiserum against a phenolic A-ring of estrogenic receptors through protein A. The QCM response exhibited stretched exponential kinetics of negative frequency shifts with reversible and "irreversible" components of mass uptake onto the sensor surface in static headspace conditions when exposed to water solutions of ETED over the sensor working range, from 10(-10) to 10(-17) g L(-1). It was shown that the variations in the QCM response characteristics are due to the change of the water-binding capacity of the sensing layer induced by protein transformations initiated by the binding of ETED molecules. This result is well correlated with the natural physiological function of estrogens in controlling the homeostasis of body fluids in living beings.

  15. Buffering action of human dentin in vitro.

    Science.gov (United States)

    Camps, J; Pashley, D H

    2000-01-01

    The purpose of this study was to determine the relative contributions of the mineral and organic phases of dentin to its total buffering capacity and to compare the buffering abilities of normal and caries-affected dentin for acids used in adhesive dentistry. Disks of normal and caries-affected human coronal dentin 0.6 mm thick were prepared. Fifty microL of various acids were applied to the surface of mineralized or completely demineralized dentin for varying lengths of time. They were collected from the surface and combined with water rinses to permit titration of the total amount of acid applied, the amount recovered, the total amount that was taken up by the dentin, and the amount that diffused across dentin into 1 mL of water. Equal volumes of acids were applied to mineralized or demineralized dentin powder or hydroxyapatite powder. About 88% to 90% of applied acid was recovered from the surface; only 10% to 12% of the acid was taken up by dentin. Of the H+ that was taken up, only 1% to 2% actually diffused across 0.6 mm of dentin. Increasing the application time of 37% phosphoric acid did not increase the amount of H+ that diffused across dentin. Increasing the concentration of phosphoric acid from 10% to 65% produced only slight increases in H+ diffusion across dentin. There was no difference in the buffering capacity of normal vs caries-affected dentin disks. Almost all of the buffering capacity of dentin is due to its mineral phase. The high buffering capacity of dentin and the high reactivity of H+ insure that little H+ diffuses through dentin more than 0.6 mm thick.

  16. Study of shallow trench isolation technology with a poly-Si sidewall buffer layer

    International Nuclear Information System (INIS)

    Juang, M H; Chen, C L; Jang, S L

    2008-01-01

    Shallow trench isolation (STI) technology with a poly-Si buffer layer at the trench sidewall has been studied. At the densification temperature of 950 °C, for the samples without using a poly-Si buffer layer, the resulting junction shows a leakage of about 700 nA cm −2 for a diode area of 100 × 100 µm 2 , primarily due to large peripheral junction leakage. The large leakage is ascribed to the defect generation caused by a thermally induced stress near the trench sidewall. The usage of a poly-Si buffer layer in the trench sidewall is found to significantly improve the junction characteristics. As a result, when a 40 nm poly-Si buffer layer is sandwiched between the Si substrate and the trench-fill silicon oxide, the resultant junctions show a leakage of only about 8 nA cm −2 . This result may reflect the considerably reduced thermally induced stress near the trench sidewall. Furthermore, at the densification temperature of 1100 °C, the usage of a poly-Si buffer layer can help to achieve excellent junctions with a leakage smaller than 5 nA cm −2 for a diode area of 100 × 100 µm 2

  17. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    DEFF Research Database (Denmark)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouther L.J.

    2013-01-01

    Oxytocin is a peptide drug used to induce labor and prevent bleeding after childbirth. Due to its instability, transport and storage of oxytocin formulations under tropical conditions is problematic. In a previous study, we have found that the stability of oxytocin in aspartate buffered formulati...

  18. Estimating values for the moisture source load and buffering capacities from indoor climate measurements

    NARCIS (Netherlands)

    Schijndel, van A.W.M.

    2008-01-01

    The objective of this study is to investigate the potential for estimating values for the total size of human induced moisture source load and the total buffering (moisture storage) capacity of the interior objects with the use of relatively simple measurements and the use of heat, air, and moisture

  19. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    NARCIS (Netherlands)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouter L J; Frijlink, Henderik W; Mulder, Frans A A

    2013-01-01

    Oxytocin is a peptide drug used to induce labor and prevent bleeding after childbirth. Due to its instability, transport and storage of oxytocin formulations under tropical conditions is problematic. In a previous study, we have found that the stability of oxytocin in aspartate buffered formulation

  20. Low energy electron attachment to SF6 in N2, Ar, and Xe buffer gases

    International Nuclear Information System (INIS)

    Hunter, S.R.; Carter, J.G.; Christophorou, L.G.

    1989-01-01

    The electron attachment rate constants k/sub a/ for SF 6 have been measured in dilute mixtures of SF 6 in high pressure (>1 atm) N 2 , Ar, and Xe buffer gases at room temperature (T≅300 K) over a wide E/N range (electric field strength to gas number density ratio), corresponding to mean electron energies from near thermal electron energies (≅0.04 eV) to ≅4.3 eV. Particular attention has been paid to the effects of space charge distortion, molecular impurities, and changes in the electron energy distribution function on the measured electron attachment rate constant values at the lower E/N values in these mixtures. The present measured thermal electron attachment rate constants in SF 6 /N 2 and SF 6 /Xe gas mixtures are in excellent agreement with recent accurate measurements of these parameters in several SF 6 /buffer gas mixtures. At higher values, the present SF 6 /N 2 measurements are in fair agreement with previous measurements, while no previous measurements using Ar and Xe buffer gases have been published. These measurements have been used in numerical two term, spherical harmonic Boltzmann equation analyses of the electron motion in these gas mixtures to obtain the low energy ( 6 . The present derived electron attachment cross sections are compared with recently measured and derived nondissociative and dissociative electron attachment cross sections for SF 6

  1. Low-Cost Real-Time Gas Monitoring Using a Laser Plasma Induced by a Third Harmonic Q-Switched Nd-YAG Laser

    Directory of Open Access Journals (Sweden)

    Syahrun Nur Abdulmadjid

    2005-11-01

    Full Text Available A gas plasma induced by a third harmonic Nd-YAG laser with relatively low pulsed energy (about 10 mJ has favorable characteristics for gas analysis due to its low background characteristics, nevertheless a high power fundamental Nd-YAG laser (100-200 mJ is widely used for laser gas breakdown spectroscopy. The air plasma can be used as a low-cost real-time gas monitoring system such that it can be used to detect the local absolute humidity, while a helium plasma can be used for gas analysis with a high level of sensitivity. A new technique using a helium plasma to improve laser ablation emission spectroscopy is proposed. Namely, the third harmonic Nd-YAG laser is focused at a point located some distance from the target in the 1-atm helium surrounding gas. By using this method, the ablated vapor from the target is excited through helium atoms in a metastable state in the helium plasma.

  2. Growth and micro structural studies on Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.; Bhatnagar, A.K. [Univ. of Hyderabad (India); Pinto, R. [Solid State Electronics Group, Bombay (India)] [and others

    1994-12-31

    Microstructure of Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) of radio frequency magnetron sputtered buffer layers was studied at various sputtering conditions on Si<100>, Sapphire and LaAlO{sub 3} <100> substrates. The effect of substrate temperatures upto 800 C and sputtering gas pressures in the range of 50 mTorr. of growth conditions was studied. The buffer layers of YSZ and STO showed a strong tendency for columnar structure with variation growth conditions. The buffer layers of YSZ and STO showed orientation. The tendency for columnar growth was observed above 15 mTorr sputtering gas pressure and at high substrate temperatures. Post annealing of these films in oxygen atmosphere reduced the oxygen deficiency and strain generated during growth of the films. Strong c-axis oriented superconducting YBa{sub 2}Cu{sub 9}O{sub 7-x} (YBCO) thin films were obtained on these buffer layers using pulsed laser ablation technique. YBCO films deposited on multilayers of YSZ and STO were shown to have better superconducting properties.

  3. Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy

    Directory of Open Access Journals (Sweden)

    Suborov Evgeny V

    2012-06-01

    Full Text Available Abstract Background Mechanical ventilation with high tidal volumes may cause ventilator-induced lung injury (VILI and enhanced generation of nitric oxide (NO. We demonstrated in sheep that pneumonectomy followed by injurious ventilation promotes pulmonary edema. We wished both to test the hypothesis that neuronal NOS (nNOS, which is distributed in airway epithelial and neuronal tissues, could be involved in the pathogenesis of VILI and we also aimed at investigating the influence of an inhibitor of nNOS on the course of VILI after pneumonectomy. Methods Anesthetized sheep underwent right pneumonectomy, mechanical ventilation with tidal volumes (VT of 6 mL/kg and FiO2 0.5, and were subsequently randomized to a protectively ventilated group (PROTV; n = 8 keeping VT and FiO2 unchanged, respiratory rate (RR 25 inflations/min and PEEP 4 cm H2O for the following 8 hrs; an injuriously ventilated group with VT of 12 mL/kg, zero end-expiratory pressure, and FiO2 and RR unchanged (INJV; n = 8 and a group, which additionally received the inhibitor of nNOS, 7-nitroindazole (NI 1.0 mg/kg/h intravenously from 2 hours after the commencement of injurious ventilation (INJV + NI; n = 8. We assessed respiratory, hemodynamic and volumetric variables, including both the extravascular lung water index (EVLWI and the pulmonary vascular permeability index (PVPI. We measured plasma nitrite/nitrate (NOx levels and examined lung biopsies for lung injury score (LIS. Results Both the injuriously ventilated groups demonstrated a 2–3-fold rise in EVLWI and PVPI, with no significant effects of NI. In the INJV group, gas exchange deteriorated in parallel with emerging respiratory acidosis, but administration of NI antagonized the derangement of oxygenation and the respiratory acidosis significantly. NOx displayed no significant changes and NI exerted no significant effect on LIS in the INJV group. Conclusion Inhibition of nNOS improved gas exchange

  4. Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy.

    Science.gov (United States)

    Suborov, Evgeny V; Smetkin, Alexey A; Kondratiev, Timofey V; Valkov, Andrey Y; Kuzkov, Vsevolod V; Kirov, Mikhail Y; Bjertnaes, Lars J

    2012-06-21

    Mechanical ventilation with high tidal volumes may cause ventilator-induced lung injury (VILI) and enhanced generation of nitric oxide (NO). We demonstrated in sheep that pneumonectomy followed by injurious ventilation promotes pulmonary edema. We wished both to test the hypothesis that neuronal NOS (nNOS), which is distributed in airway epithelial and neuronal tissues, could be involved in the pathogenesis of VILI and we also aimed at investigating the influence of an inhibitor of nNOS on the course of VILI after pneumonectomy. Anesthetized sheep underwent right pneumonectomy, mechanical ventilation with tidal volumes (VT) of 6 mL/kg and FiO2 0.5, and were subsequently randomized to a protectively ventilated group (PROTV; n = 8) keeping VT and FiO2 unchanged, respiratory rate (RR) 25 inflations/min and PEEP 4 cm H2O for the following 8 hrs; an injuriously ventilated group with VT of 12 mL/kg, zero end-expiratory pressure, and FiO2 and RR unchanged (INJV; n = 8) and a group, which additionally received the inhibitor of nNOS, 7-nitroindazole (NI) 1.0 mg/kg/h intravenously from 2 hours after the commencement of injurious ventilation (INJV + NI; n = 8). We assessed respiratory, hemodynamic and volumetric variables, including both the extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI). We measured plasma nitrite/nitrate (NOx) levels and examined lung biopsies for lung injury score (LIS). Both the injuriously ventilated groups demonstrated a 2-3-fold rise in EVLWI and PVPI, with no significant effects of NI. In the INJV group, gas exchange deteriorated in parallel with emerging respiratory acidosis, but administration of NI antagonized the derangement of oxygenation and the respiratory acidosis significantly. NOx displayed no significant changes and NI exerted no significant effect on LIS in the INJV group. Inhibition of nNOS improved gas exchange, but did not reduce lung water extravasation following

  5. A gas circulation and purification system for gas-cell-based low-energy RI-beam production

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, T.; Wada, M.; Katayama, I.; Kojima, T. M.; Reponen, M. [RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsubota, T. [Tokyo KOATSU Co., Ltd., 1-9-8 Shibuya, Shibuyaku, Tokyo 150-0002 (Japan)

    2016-06-15

    A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

  6. On-line determination of iodine in nuclear fuel reprocessing off-gas streams by a combination of laser-induced fluorimetry and laser photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Kuno, Yusuke; Sato, Souichi; Masui, Jinichi

    1992-01-01

    The on-line determination of molecular iodine and organic iodides in nuclear fuel reprocessing off-gas streams containing high concentrations of NO x gas was studied. Ultraviolet radiation is used to convert organic iodides into molecular iodine. The approximate concentration of iodine before and after the photochemical conversion in the presence of NO x gas was first determined by laser-induced fluorimetry. NO 2 was determined by photoacoustic spectroscopy, correcting the acoustic signal due to iodine by using the approximate iodine concentration. NO was determined from the concentrations of NO 2 before and after the photoirradiation based on the photochemical fraction changes of NO and NO 2 . The quenching of the fluorimetry due to NO and NO 2 was finally corrected with the NO and NO 2 concentrations obtained. The detection limit of the proposed method is 10 nl 1 -1 . 7 figs., 2 tabs., 11 refs

  7. Coupled microrings data buffer using fast light

    Science.gov (United States)

    Scheuer, Jacob; Shahriar, Selim

    2013-03-01

    We present a theoretical study of a trap-door optical buffer based on a coupled microrings add/drop filter (ADF) utilizing the white light cavity (WLC). The buffer "trap-door" can be opened and closed by tuning the resonances of the microrings comprising the ADF and trap/release optical pulses. We show that the WLC based ADF yields a maximally flat filter which exhibits superior performances in terms of bandwidth and flatness compared to previous design approaches. We also present a realistic, Silicon-over-Insulator based, design and performance analysis taking into consideration the realistic properties and limitations of the materials and the fabrication process, leading to delays exceeding 850ps for 80GHz bandwidth, and a corresponding delay-bandwidth product of approximately 70.

  8. MOISTURE-BUFFERING CHARACTERISTICS OF BUILDING MATERIALS

    Directory of Open Access Journals (Sweden)

    Young Cheol Choi

    2016-05-01

    Full Text Available The humidity level of indoor air is an important factor influencing the air quality and energy consumption of buildings, as well as the durability of building components. Indoor humidity levels depend on several factors, such as moisture sources, air flow, and the adsorption/desorption properties of materials. The moisture-buffering characteristics of building materials that are in contact with indoor air may help moderate the variations of indoor humidity, especially in the summer and winter. In this study, the moisture adsorption/desorption properties of building materials were investigated experimentally and numerically. These properties can be used to characterize the ability of building materials to exchange moisture with the indoor environment. This study indicates that a building material surface resistivity was the main factor creating variations of moisture buffering.

  9. Chemical buffering capacity of clay rock

    International Nuclear Information System (INIS)

    Beaucaire, C.; Pearson, F.J.; Gautschi, A.

    2004-01-01

    The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

  10. Microbial activity in bentonite buffers. Literature study

    Energy Technology Data Exchange (ETDEWEB)

    Ratto, M.; Itavaara, M.

    2012-07-01

    The proposed disposal concept for high-level radioactive wastes involves storing the wastes underground in copper-iron containers embedded in buffer material of compacted bentonite. Hydrogen sulphide production by sulphate-reducing prokaryotes is a potential mechanism that could cause corrosion of waste containers in repository conditions. The prevailing conditions in compacted bentonite buffer will be harsh. The swelling pressure is 7-8 MPa, the amount of free water is low and the average pore and pore throat diameters are small. This literature study aims to assess the potential of microbial activity in bentonite buffers. Literature on the environmental limits of microbial life in extreme conditions and the occurrence of sulphatereducing prokaryotes in extreme environments is reviewed briefly and the results of published studies characterizing microbes and microbial processes in repository conditions or in relevant subsurface environments are presented. The presence of bacteria, including SRBs, has been confirmed in deep groundwater and bentonite-based materials. Sulphate reducers have been detected in various high-pressure environments, and sulphate-reduction based on hydrogen as an energy source is considered a major microbial process in deep subsurface environments. In bentonite, microbial activity is strongly suppressed, mainly due to the low amount of free water and small pores, which limit the transport of microbes and nutrients. Spore-forming bacteria have been shown to survive in compacted bentonite as dormant spores, and they are able to resume a metabolically active state after decompaction. Thus, microbial sulphide production may increase in repository conditions if the dry density of the bentonite buffer is locally reduced. (orig.)

  11. Isostatic compression of buffer blocks. Middle scale

    International Nuclear Information System (INIS)

    Ritola, J.; Pyy, E.

    2012-01-01

    Manufacturing of buffer components using isostatic compression method has been studied in small scale in 2008 (Laaksonen 2010). These tests included manufacturing of buffer blocks using different bentonite materials and different compression pressures. Isostatic mould technology was also tested, along with different methods to fill the mould, such as vibration and partial vacuum, as well as a stepwise compression of the blocks. The development of manufacturing techniques has continued with small-scale (30 %) blocks (diameter 600 mm) in 2009. This was done in a separate project: Isostatic compression, manufacturing and testing of small scale (D = 600 mm) buffer blocks. The research on the isostatic compression method continued in 2010 in a project aimed to test and examine the isostatic manufacturing process of buffer blocks at 70 % scale (block diameter 1200 to 1300 mm), and the aim was to continue in 2011 with full-scale blocks (diameter 1700 mm). A total of nine bentonite blocks were manufactured at 70 % scale, of which four were ring-shaped and the rest were cylindrical. It is currently not possible to manufacture full-scale blocks, because there is no sufficiently large isostatic press available. However, such a compression unit is expected to be possible to use in the near future. The test results of bentonite blocks, produced with an isostatic pressing method at different presses and at different sizes, suggest that the technical characteristics, for example bulk density and strength values, are somewhat independent of the size of the block, and that the blocks have fairly homogenous characteristics. Water content and compression pressure are the two most important properties determining the characteristics of the compressed blocks. By adjusting these two properties it is fairly easy to produce blocks at a desired density. The commonly used compression pressure in the manufacturing of bentonite blocks is 100 MPa, which compresses bentonite to approximately

  12. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

    Science.gov (United States)

    Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

    2015-01-01

    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

  13. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture.

    Science.gov (United States)

    Mauceri, Daniela; Hagenston, Anna M; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

    2015-09-18

    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Isostatic compression of buffer blocks. Middle scale

    Energy Technology Data Exchange (ETDEWEB)

    Ritola, J.; Pyy, E. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2012-01-15

    Manufacturing of buffer components using isostatic compression method has been studied in small scale in 2008 (Laaksonen 2010). These tests included manufacturing of buffer blocks using different bentonite materials and different compression pressures. Isostatic mould technology was also tested, along with different methods to fill the mould, such as vibration and partial vacuum, as well as a stepwise compression of the blocks. The development of manufacturing techniques has continued with small-scale (30 %) blocks (diameter 600 mm) in 2009. This was done in a separate project: Isostatic compression, manufacturing and testing of small scale (D = 600 mm) buffer blocks. The research on the isostatic compression method continued in 2010 in a project aimed to test and examine the isostatic manufacturing process of buffer blocks at 70 % scale (block diameter 1200 to 1300 mm), and the aim was to continue in 2011 with full-scale blocks (diameter 1700 mm). A total of nine bentonite blocks were manufactured at 70 % scale, of which four were ring-shaped and the rest were cylindrical. It is currently not possible to manufacture full-scale blocks, because there is no sufficiently large isostatic press available. However, such a compression unit is expected to be possible to use in the near future. The test results of bentonite blocks, produced with an isostatic pressing method at different presses and at different sizes, suggest that the technical characteristics, for example bulk density and strength values, are somewhat independent of the size of the block, and that the blocks have fairly homogenous characteristics. Water content and compression pressure are the two most important properties determining the characteristics of the compressed blocks. By adjusting these two properties it is fairly easy to produce blocks at a desired density. The commonly used compression pressure in the manufacturing of bentonite blocks is 100 MPa, which compresses bentonite to approximately

  15. META-ANALYSIS OF NITROGEN REMOVAL IN RIPARIAN BUFFERS

    Science.gov (United States)

    Riparian buffer zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Riparian buffer width may be positively related to nitrogen removal effectiveness by influencing nitrog...

  16. Methyl Bromide Commodity Fumigation Buffer Zone Lookup Tables

    Science.gov (United States)

    Product labels for methyl bromide used in commodity and structural fumigation include requirements for buffer zones around treated areas. The information on this page will allow you to find the appropriate buffer zone for your planned application.

  17. Success and failure with phthalate buffers in capillary zone electrophoresis

    NARCIS (Netherlands)

    Bocek, P.; Gebauer, P.; Beckers, J.L.

    2001-01-01

    Phthalate buffers are currently used in capillary electrophoresis as robust electrolyte systems for indirect detection. This contribution demonstrates that these buffers show regularly not only successful regions of mobilities of analytes (sample window) but also regions of failure where the

  18. Prevalence and risk factors of noise-induced hearing loss among liquefied petroleum gas (LPG) cylinder infusion workers in Taiwan.

    Science.gov (United States)

    Chang, Shu-Ju; Chang, Chin-Kuo

    2009-12-01

    We assessed the exposure levels of noise, estimated prevalence, and identify risk factors of noise-induced hearing loss (NIHL) among male workers with a cross-sectional study in a liquefied petroleum gas cylinder infusion factory in Taipei City. Male in-field workers exposed to noise and administrative controls were enrolled in 2006 and 2007. Face-to-face interviews were applied for demographics, employment history, and drinking/smoking habit. We then performed the measurements on noise levels in field and administration area, and hearing thresholds on study subjects with standard apparatus and protocols. Existence of hearing loss > 25 dBHL for the average of 500 Hz, 1 kHz, and 2 kHz was accordingly determined for NIHL. The effects from noise exposure, predisposing characteristics, employment-related factors, and personal habits to NIHL were estimated by univariate and multivariate logistic regressions. A total of 75 subjects were involved in research and 56.8% of in-field workers had NIHL. Between the in-field and administration groups, hearing thresholds on the worse ear showed significant differences at frequencies of 4 k, 6 k, and 8 kHz with aging considered. Adjusted odds ratio for field noise exposure (OR=99.57, 95% CI: 3.53, 2,808.74) and frequent tea or coffee consumption (OR=0.03, 95% CI: 0.01, 0.51) were found significant. Current study addressed NIHL in a specific industry in Taiwan. Further efforts in minimizing its impact are still in need.

  19. Numerical and experimental investigation of laser induced plasma spectrum of aluminum in the presence of a noble gas

    International Nuclear Information System (INIS)

    Rezaei, Fatemeh; Tavassoli, Seyed Hassan

    2012-01-01

    Laser-induced plasma emission of an aluminum target in helium gas at 1 atm pressure is numerically and experimentally investigated. A laser pulse at wavelength of 266 nm and pulse duration of 10 ns has been considered. Laser ablation is calculated by a one dimensional model based on thermal evaporation mechanism. Spatial and temporal parameters of plasma expansion are determined by using hydrodynamic equations. Three kinds of plasma emission, including Bremsstrahlung, recombination and spectral emissions are considered for modeling the spectrum. Strong lines of aluminum and helium in wavelength interval of 200 to 450 nm are selected. Aluminum spectrum in UV range is depicted and compared with other spectral ranges. Temporal and spatial evolution of plasma emission up to 200 ns after the laser irradiation is studied. The effect of laser energy on the plasma spectrum is studied. An experimental set-up is arranged to compare numerical calculations with experimental results. Experimental and numerical results illustrate that helium line widths and peak intensities become narrower and weaker with time, respectively. Spatial distribution of spectrum shows that for closer distance to the sample surface, an intense continuous emission is observed, while at the farther distance, continuous emission decreases and spectral lines become sharper. A good coincidence is observed between experimental and numerical results. - Highlights: ► Aluminum plasma emission in helium is numerically and experimentally studied. ► Spectral, Bremsstrahlung and recombination emissions in spectrum are calculated. ► All strong lines of aluminum and helium are chosen for spectrum simulation. ► Line widths and peak intensities at later times become narrower and weaker. ► At specific optimum position, the maximum of signal peaks is acquired.

  20. Numerical and experimental investigation of laser induced plasma spectrum of aluminum in the presence of a noble gas

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, Fatemeh, E-mail: f_rezaei@sbu.ac.ir; Tavassoli, Seyed Hassan

    2012-12-01

    Laser-induced plasma emission of an aluminum target in helium gas at 1 atm pressure is numerically and experimentally investigated. A laser pulse at wavelength of 266 nm and pulse duration of 10 ns has been considered. Laser ablation is calculated by a one dimensional model based on thermal evaporation mechanism. Spatial and temporal parameters of plasma expansion are determined by using hydrodynamic equations. Three kinds of plasma emission, including Bremsstrahlung, recombination and spectral emissions are considered for modeling the spectrum. Strong lines of aluminum and helium in wavelength interval of 200 to 450 nm are selected. Aluminum spectrum in UV range is depicted and compared with other spectral ranges. Temporal and spatial evolution of plasma emission up to 200 ns after the laser irradiation is studied. The effect of laser energy on the plasma spectrum is studied. An experimental set-up is arranged to compare numerical calculations with experimental results. Experimental and numerical results illustrate that helium line widths and peak intensities become narrower and weaker with time, respectively. Spatial distribution of spectrum shows that for closer distance to the sample surface, an intense continuous emission is observed, while at the farther distance, continuous emission decreases and spectral lines become sharper. A good coincidence is observed between experimental and numerical results. - Highlights: Black-Right-Pointing-Pointer Aluminum plasma emission in helium is numerically and experimentally studied. Black-Right-Pointing-Pointer Spectral, Bremsstrahlung and recombination emissions in spectrum are calculated. Black-Right-Pointing-Pointer All strong lines of aluminum and helium are chosen for spectrum simulation. Black-Right-Pointing-Pointer Line widths and peak intensities at later times become narrower and weaker. Black-Right-Pointing-Pointer At specific optimum position, the maximum of signal peaks is acquired.

  1. N-decane-air end-gas auto-ignition induced by flame propagation in a constant volume chamber: Influence of compression history

    OpenAIRE

    Quintens , Hugo; Strozzi , Camille; Zitoun , Ratiba; Bellenoue , Marc

    2017-01-01

    International audience; The present study aims at characterizing the end-gas auto-ignition of n-decane – air mixtures induced by a flame propagation in a constant volume chamber. A numerical tool is developed, and the study is first focused on academic compressions, e.g. at constant rate of pressure rise. Thermodynamic conditions of transition from deflagration to auto-ignition are first determined, and the involved physical processes are highlighted. A square section combustion chamber is th...

  2. International comparison of observation-specific spatial buffers

    DEFF Research Database (Denmark)

    Frank, Lawrence D; Fox, Eric H; Ulmer, Jared M

    2017-01-01

    the relative differences in resulting explanatory power on self-reported physical activity outcomes. BEMs were developed in five countries using 'sausage,' 'detailed-trimmed,' and 'detailed,' network buffers at a distance of 1 km around participant household addresses (n = 5883). RESULTS: BEM values were...... significantly different (p trimmed buffer comparisons and 89% of sausage versus detailed network buffer comparisons. Results showed that BEM coefficients in physical activity models did not differ significantly across buffering methods, and in most cases BEM...

  3. Evaluation of buffer zone effectiveness in mitigating the risks associated with agricultural runoff in Prince Edward Island.

    Science.gov (United States)

    Dunn, A M; Julien, G; Ernst, W R; Cook, A; Doe, K G; Jackman, P M

    2011-02-01

    To minimize the risk posed by runoff from row crops, Prince Edward Island introduced buffer legislation in 2000. The legislation mandates 10-m and 20-m buffers, respectively, for moderate sloped (i.e. 5%) agricultural fields that border streams. Since 2001, Environment Canada has been evaluating the effectiveness of various buffer widths on operational farms in reducing toxicity and contaminant concentrations in runoff. Sample collectors, placed in 44 fields at the field edge (0m), 10m and at distances out to 30m, collected overland flow following rainfall-induced runoff events. Samples were collected within 24 hours of an event and analysed for seven pesticides (endosulfan, chlorothalonil, carbofuran, linuron, metribuzin, metalaxyl, mancozeb), water quality parameters and Daphnia magna toxicity. The 10-m buffer required for moderate sloped fields was effective at reducing contaminant concentrations but not always to less than lethal concentrations to Daphnia magna. Limited data beyond 10m for fields of both slope types precluded making recommendations on a suitable buffer width for shallow sloped fields and evaluating the effectiveness of 20-m buffers for steep sloped fields. When paired data were combined and statistically tested for all fields, the studied pesticides underwent a 52-98% and 68-100% reduction in aqueous and particulate concentrations within 10m and 30m, respectively. In addition, by 10m, soluble phosphorus, nitrate-nitrogen and total suspended solids were reduced by 34%, 38% and 64%, respectively. Results suggest buffer zones on operational farms are capable of achieving contaminant reductions comparable to those reported for controlled experiments. Inconsistent siting of sample collectors beyond 10m limited the evaluation of the effects of field slope and buffer width on buffer effectiveness on working farms. Future studies on buffer efficiency on operational farms should focus on building the data set beyond 10m and evaluating load reductions

  4. Increase of weakly acidic gas esophagopharyngeal reflux (EPR) and swallowing-induced acidic/weakly acidic EPR in patients with chronic cough responding to proton pump inhibitors.

    Science.gov (United States)

    Kawamura, O; Shimoyama, Y; Hosaka, H; Kuribayashi, S; Maeda, M; Nagoshi, A; Zai, H; Kusano, M

    2011-05-01

    Gastro-esophageal reflux disease (GERD)-related chronic cough (CC) may have multifactorial causes. To clarify the characteristics of esophagopharyngeal reflux (EPR) events in CC patients whose cough was apparently influenced by gastro-esophageal reflux (GER), we studied patients with CC clearly responding to full-dose proton pump inhibitor (PPI) therapy (CC patients). Ten CC patients, 10 GERD patients, and 10 healthy controls underwent 24-h ambulatory pharyngo-esophageal impedance and pH monitoring. Weakly acidic reflux was defined as a decrease of pH by >1 unit with a nadir pH >4. In six CC patients, monitoring was repeated after 8 weeks of PPI therapy. The number of each EPR event and the symptom association probability (SAP) were calculated. Symptoms were evaluated by a validated GERD symptom questionnaire. Weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR only occurred in CC patients, and the numbers of such events was significantly higher in the CC group than in the other two groups (P pump inhibitor therapy abolished swallowing-induced acidic/weakly acidic EPR, reduced weakly acidic gas EPR, and improved symptoms (all P gas EPR and swallowing-induced acidic/weakly acidic EPR. A direct effect of acidic mist or liquid refluxing into the pharynx may contribute to chronic cough, while cough may also arise indirectly from reflux via a vago-vagal reflex in some patients. © 2011 Blackwell Publishing Ltd.

  5. Complexation of buffer constituents with neutral complexation agents: part I. Impact on common buffer properties.

    Science.gov (United States)

    Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

    2013-09-17

    The complexation of buffer constituents with the complexation agent present in the solution can very significantly influence the buffer properties, such as pH, ionic strength, or conductivity. These parameters are often crucial for selection of the separation conditions in capillary electrophoresis or high-pressure liquid chromatography (HPLC) and can significantly affect results of separation, particularly for capillary electrophoresis as shown in Part II of this paper series (Beneš, M.; Riesová, M.; Svobodová, J.; Tesařová, E.; Dubský, P.; Gaš, B. Anal. Chem. 2013, DOI: 10.1021/ac401381d). In this paper, the impact of complexation of buffer constituents with a neutral complexation agent is demonstrated theoretically as well as experimentally for the model buffer system composed of benzoic acid/LiOH or common buffers (e.g., CHES/LiOH, TAPS/LiOH, Tricine/LiOH, MOPS/LiOH, MES/LiOH, and acetic acid/LiOH). Cyclodextrins as common chiral selectors were used as model complexation agents. We were not only able to demonstrate substantial changes of pH but also to predict the general complexation characteristics of selected compounds. Because of the zwitterion character of the common buffer constituents, their charged forms complex stronger with cyclodextrins than the neutral ones do. This was fully proven by NMR measurements. Additionally complexation constants of both forms of selected compounds were determined by NMR and affinity capillary electrophoresis with a very good agreement of obtained values. These data were advantageously used for the theoretical descriptions of variations in pH, depending on the composition and concentration of the buffer. Theoretical predictions were shown to be a useful tool for deriving some general rules and laws for complexing systems.

  6. Using fluorescent dyes as proxies to study herbicide removal by sorption in buffer zones.

    Science.gov (United States)

    Dollinger, Jeanne; Dagès, Cécile; Voltz, Marc

    2017-04-01

    The performance of buffer zones for removing pesticides from runoff water varies greatly according to landscape settings, hydraulic regime, and system design. Evaluating the performance of buffers for a range of pesticides and environmental conditions can be very expensive. Recent studies suggested that the fluorescent dyes uranine and sulforhodamine B could be used as cost-effective surrogates of herbicides to evaluate buffer performance. However, while transformation mechanisms in buffers have been extensively documented, sorption processes of both dyes have rarely been investigated. In this study, we measured the adsorption, desorption, and kinetic sorption coefficients of uranine and sulforhodamine B for a diverse range of buffer zone materials (soils, litters, plants) and compared the adsorption coefficients (Kd) to those of selected herbicides. We also compared the global sorption capacity of 6 ditches, characterized by varying proportions of the aforementioned materials, between both dyes and a set of four herbicides using the sorption-induced pesticide retention indicator (SPRI). We found that both the individual Kd of uranine for the diverse buffer materials and the global sorption capacity of the ditches are equivalent to those of the herbicides diuron, isoproturon, and metolachlor. The Kd of sulforhodamine B on plants and soils are equivalent to those of glyphosate, and the global sorption capacities of the ditches are equivalent for both molecules. Hence, we demonstrate for the first time that uranine can be used as a proxy of moderately hydrophobic herbicides to evaluate the performance of buffer systems, whereas sulforhodamine B can serve as a proxy for more strongly sorbing herbicides.

  7. Microchannel electrokinetics of charged analytes in buffered solutions near floating electrodes

    DEFF Research Database (Denmark)

    Andersen, Mathias Bækbo; Wolfcale, Trevor; Gregersen, Misha Marie

    to accurately predict such behavior in these flow regimes. Experimentally, using conventional fluorescence microscopy, we investigated the concentration gradient (as well as the associated electroosmosis, induced-charge electro-osmosis, and electrophoresis) of the charged analyte near the floating electrode......We present both experimental and numerical studies of nonlinear electrokinetic flow of buffered solutions seeded with dilute analytes in a straight microchannel (0.6 μm high, 250 μm wide, and 9000 μm long) with a 0.15 μm high 60 μm wide electrode situated at the bottom center of the channel...... as a function of analyte (1 to 10 μM fluorescein and bodipy) and buffer (1 to 10 mM borate and posphate) concentrations and an externally applied voltage drop (50 to 100 V) along the channel. We have implemented a nonlinear continuum kinetics model of the system involving the electric potential, the buffer flow...

  8. Further improvements in competitive guarantees for QoS buffering

    NARCIS (Netherlands)

    Bansal, N.; Fleischer, L.K.; Kimbrel, T.; Mahdian, M.; Schieber, B.; Sviridenko, M.; Diaz, J.; Karhumäki, J.; Lepistö, A.; Sannella, D.

    2004-01-01

    We study the behavior of algorithms for buffering packets weighted by different levels of Quality of Service (QoS) guarantees in a single queue. Buffer space is limited, and packet loss occurs when the buffer overflows. We describe a modification of the previously proposed ``preemptive greedy{''}

  9. Towards Optimal Buffer Size in Wi-Fi Networks

    KAUST Repository

    Showail, Ahmad J.

    2016-01-19

    Buffer sizing is an important network configuration parameter that impacts the quality of data traffic. Falling memory cost and the fallacy that ‘more is better’ lead to over provisioning network devices with large buffers. Over-buffering or the so called ‘bufferbloat’ phenomenon creates excessive end-to-end delay in today’s networks. On the other hand, under-buffering results in frequent packet loss and subsequent under-utilization of network resources. The buffer sizing problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environment. In this dissertation, we discuss buffer sizing challenges in wireless networks, classify the state-of-the-art solutions, and propose two novel buffer sizing schemes. The first scheme targets buffer sizing in wireless multi-hop networks where the radio spectral resource is shared among a set of con- tending nodes. Hence, it sizes the buffer collectively and distributes it over a set of interfering devices. The second buffer sizing scheme is designed to cope up with recent Wi-Fi enhancements. It adapts the buffer size based on measured link characteristics and network load. Also, it enforces limits on the buffer size to maximize frame aggregation benefits. Both mechanisms are evaluated using simulation as well as testbed implementation over half-duplex and full-duplex wireless networks. Experimental evaluation shows that our proposal reduces latency by an order of magnitude.

  10. Managing Multiuser Database Buffers Using Data Mining Techniques

    NARCIS (Netherlands)

    Feng, L.; Lu, H.J.

    2004-01-01

    In this paper, we propose a data-mining-based approach to public buffer management for a multiuser database system, where database buffers are organized into two areas – public and private. While the private buffer areas contain pages to be updated by particular users, the public

  11. Heed the head: buffer benefits along headwater streams

    Science.gov (United States)

    Rhonda Mazza; Deanna (Dede) Olson

    2015-01-01

    Since the Northwest Forest Plan implemented riparian buffers along non-fish bearing streams in 1994, there have been questions about how wide those buffers need to be to protect aquatic and riparian resources from upland forest management activities. The Density Management and Riparian Buffer Study of western Oregon, also initiated in 1994, examines the effects of...

  12. Concentrated flow paths in riparian buffer zones of southern Illinois

    Science.gov (United States)

    R.C. Pankau; J.E. Schoonover; K.W.J. Willard; P.J. Edwards

    2012-01-01

    Riparian buffers in agricultural landscapes should be designed to trap pollutants in overland flow by slowing, filtering, and infiltrating surface runoff entering the buffer via sheet flow. However, observational evidence suggests that concentrated flow is prevalent from agricultural fields. Over time sediment can accumulate in riparian buffers forming berms that...

  13. Stream water responses to timber harvest: Riparian buffer width effectiveness

    Science.gov (United States)

    Barton D. Clinton

    2011-01-01

    Vegetated riparian buffers are critical for protecting aquatic and terrestrial processes and habitats in southern Appalachian ecosystems. In this case study, we examined the effect of riparian buffer width on stream water quality following upland forest management activities in four headwater catchments. Three riparian buffer widths were delineated prior to cutting; 0m...

  14. Analysis of diffusive mass transport in a cracked buffer

    International Nuclear Information System (INIS)

    Garisto, N.C.; Garisto, F.

    1989-11-01

    In the disposal vault design for the Canadian Nuclear Fuel Waste Management Program, cylindrical containers of used nuclear fuel would be placed in vertical boreholes in rock and surrounded with a bentonite-based buffer material. The buffer is expected to absorb and/or retard radionuclides leaching from the fuel after the containers fail. There is some evidence, however, that the buffer may be susceptible to cracking. In this report we investigate numerically the consequences of cracking on uranium diffusion through the buffer. The derivation of the mass-transport equations and the numerical solution method are presented for the solubility-limited diffusion of uranium in a cracked buffer system for both swept-away and semi-impermeable boundary conditions at the rock-buffer interface. The results indicate that for swept-away boundary conditions the total uranium flux through the cracked buffer system is, as expected, greater than through the uncracked buffer. The effect of the cracks is strongly dependent on the ratio D/D eff , where D and D eff are the pore-water and the effective buffer diffusion coefficient, respectively. However, although a decrease in D eff enhances the effect of cracks on the total cumulative flux (relative to the uncracked buffer), it also decreases the total cumulative flux through the cracked buffer system (relative to a cracked buffer with a larger D eff value). Finally, for semi-impermeable boundary conditions, the effect of cracks on the total radionuclide flux is relatively small

  15. Exchangeability of bentonite buffer and backfill materials

    Energy Technology Data Exchange (ETDEWEB)

    Savage, D. [Savage Earth Associates Ltd, Bournemouth (United Kingdom); Arthur, R. [Intera Inc, Ottawa, ON, (Canada); Luukkonen, A.

    2012-08-15

    Clay-based buffer and tunnel backfill materials are important barriers in the KBS-3 repository concept for final disposal of spent nuclear fuel in Finland. One issue that is relevant to material properties is the degree to which different bentonite compositions can be regarded as interchangeable. In Posiva's current repository design, the reference bentonite composition is MX-80, a sodium montmorillonite dominated clay. Posiva would like to be able to use bentonite with Ca-montmorillonite as the dominant clay mineral. However, at this stage, it is not clear what supporting data need to be acquired/defined to be able to place the state of knowledge of Ca-bentonite at the same level as that of Na-bentonite. In this report, the concept of bentonite exchangeability has been evaluated through consideration of how bentonite behaviour may be affected in six key performance-relevant properties, namely (1) mineralogical composition and availability of materials, (2) hydraulic conductivity, (3) mechanical and rheological properties, (4) long-term alteration, (5) colloidal properties, and (6) swelling pressure. The report evaluates implications for both buffer and backfill. Summary conclusions are drawn from these sections to suggest how bentonite exchangeability may be addressed in regulatory assessments of engineered barrier design for a future geological repository for spent fuel in Finland. Some important conclusions are: (a) There are some fundamental differences between Ca- and Na-bentonites such as colloidal behaviour, pore structure and long-term alteration that could affect the exchangeability of these materials as buffer or backfill materials and which should be further evaluated; (b) Additional experimental data are desirable for some issues such as long-term alteration, hydraulic properties and swelling behaviour, (c) The minor mineral content of bentonites is very variable, both between different bentonites and within the same bentonite type, it is not clear

  16. Temporal and spatial dynamics of laser-induced aluminum plasma in argon background at atmospheric pressure: Interplay with the ambient gas

    International Nuclear Information System (INIS)

    Ma, Q.L.; Motto-Ros, V.; Lei, W.Q.; Boueri, M.; Bai, X.S.; Zheng, L.J.; Zeng, H.P.; Yu, J.

    2010-01-01

    Laser ablation in background gas implies supplementary complexities with respect to what happens in the vacuum. It is however essential to understand in detail the involved mechanisms for a number of applications requiring the ablation to be performed in an ambient gas at relative high pressure, such as pulsed-laser deposition, or laser-induced breakdown spectroscopy. In this paper, the expansion of a vapor plume ablated from an aluminum target into an argon gas at atmospheric pressure is experimentally investigated using time- and space-resolved emission spectroscopy. The obtained results provide a detailed description of the interplay between the vapor and the gas. The electron density, the temperature and the number densities (and therefore the partial pressures) of aluminum vapor and argon gas have been measured in and surrounding the vapor plume. Our observations show a confinement of the vapor plume by the gas, which is expected as predicted by the usual hydrodynamics models. The result is a plasma core with quite uniform distributions in electron density, temperature and number densities. Such plasma core presents an ideal emission source for spectroscopic applications. It is however evidenced by our observations that a large amount of argon is mixed into the aluminum plume in the plasma core, which invalidates in the experimental conditions that we used, the hydrodynamic 'piston' model where the background gas is pushed out by the shock wave surrounding the vapor plume. Instead, other mechanisms such as laser-supported detonation wave should play important roles in the early stage of the expansion of the plasma for the determination of its morphology at longer delays.

  17. Peak distortion in the column liquid chromatographic determination of omeprazole dissolved in borax buffer.

    Science.gov (United States)

    Arvidsson, T; Collijn, E; Tivert, A M; Rosén, L

    1991-11-22

    Injection of a sample containing omeprazole dissolved in borax buffer (pH 9.2) into a reversed-phase liquid chromatographic system consisting of a mixture of acetonitrile and phosphate buffer (pH 7.6) as the mobile phase and a C18 surface-modified silica as the solid phase resulted under special conditions in split peaks of omeprazole. The degree of peak split and the retention time of omeprazole varied with the concentration of borax in the sample solution and the ionic strength of the mobile phase buffer as well as with the column used. Borax is eluted from the column in a broad zone starting from the void volume of the column. The retention is probably due to the presence of polyborate ions. The size of the zone varies with the concentration of borax in the sample injected. In the borax zone the pH is increased compared with the pH of the mobile phase, and when omeprazole (a weak acid) is co-eluting in the borax zone its retention is affected. In the front part and in the back part of the borax zone, pH gradients are formed, and these gradients can induce the peak splitting. When the dissolving medium is changed to a phosphate buffer or an ammonium buffer at pH 9 no peak distortion of omeprazole is observed.

  18. Coupled behaviour of bentonite buffer results of PUSKURI project

    International Nuclear Information System (INIS)

    Olin, M.; Rasilainen, K.; Itaelae, A.

    2011-08-01

    In the report main results form a KYT2010 programme's project Coupled behaviour of bentonite buffer (PUSKURI) are presented. In THC modelling, Aku Itaelae made and published his Master of Science Thesis. Itaelae was able to successfully model the LOT-experiment. Additionally, he also listed problems and development proposals for THC-modelling of bentonite buffer. VTT and Numerola created in collaboration a model coupling saturation, diffusion and cation exchange; the model was implemented and tested in Numerrin, COMSOL and TOUGHREACT. Petri Jussila's PhD THM-model was implemented into COMSOL to facilitate further development. At GTK, the mineralogical characterisation of bentonite was planned. The previous THM model (Jussila's model) including only small deformations was successfully generalized to finite deformations in way at least formally preserving the original formalism. It appears that the theory allows also a possibility to include finite plastic deformations in the theory. In order to measure the relevant mechanical properties of compacted bentonite, two different experiments, namely hydrostatic compression experiment and one-dimensional compression experiment were designed. In the hydrostatic compression experiment, a cylindrical sample of compacted bentonite covered with liquid rubber coating is placed in the sample chamber equipped with a piston. The same device was also used in one-dimensional compression experiment. X-ray microtomographic techniques were used in order to study the basic mechanisms of water transport in bentonite. The preliminary results indicate that in the present experimental set-up, water transport is dominated by a dispersive mechanism such as diffusion of vapour in gas phase or diffusion of water in solid phase. (orig.)

  19. The cyclotron gas stopper project at the NSCL

    Energy Technology Data Exchange (ETDEWEB)

    Guenaut, C., E-mail: guenaut@nscl.msu.edu; Bollen, G.; Chouhan, S.; Marti, F.; Morrissey, D. J.; Lawton, D.; Ottarson, J.; Pang, G. K.; Schwarz, S.; Sherrill, B. M. [Michigan State University (United States); Wada, M. [RIKEN (Japan); Zeller, A. F. [Michigan State University (United States)

    2006-11-15

    Gas stopping is becoming the method of choice for converting beams of rare isotopes obtained via projectile fragmentation and in-flight separation into low-energy beams. These beams allow ISOL-type experiments, such as mass measurements with traps or laser spectroscopy, to be performed with projectile fragmentation products. Current gas stopper systems for high-energy beams are based on linear gas cells filled with 0.1-1 bar of helium. While already used successfully for experiments, it was found that space charge effects induced by the ionization of the helium atoms during the stopping process pose a limit on the maximum beam rate that can be used. Furthermore, the extraction time of stopped ions from these devices can exceed 100 ms causing substantial decay losses for very short-lived isotopes. To avoid these limitations, a new type of gas stopper is being developed at the NSCL/MSU. The new system is based on a cyclotron-type magnet with a stopping chamber filled with Helium buffer gas at low pressure. RF-guiding techniques are used to extract the ions. The space charge effects are considerably reduced by the large volume and due to a separation between the stopping region and the region of highest ionization. Cyclotron gas stopper systems of different sizes and with different magnetic field strengths and field shapes are presently investigated.

  20. The cyclotron gas stopper project at the NSCL

    International Nuclear Information System (INIS)

    Guenaut, C.; Bollen, G.; Chouhan, S.; Marti, F.; Morrissey, D. J.; Lawton, D.; Ottarson, J.; Pang, G. K.; Schwarz, S.; Sherrill, B. M.; Wada, M.; Zeller, A. F.

    2006-01-01

    Gas stopping is becoming the method of choice for converting beams of rare isotopes obtained via projectile fragmentation and in-flight separation into low-energy beams. These beams allow ISOL-type experiments, such as mass measurements with traps or laser spectroscopy, to be performed with projectile fragmentation products. Current gas stopper systems for high-energy beams are based on linear gas cells filled with 0.1-1 bar of helium. While already used successfully for experiments, it was found that space charge effects induced by the ionization of the helium atoms during the stopping process pose a limit on the maximum beam rate that can be used. Furthermore, the extraction time of stopped ions from these devices can exceed 100 ms causing substantial decay losses for very short-lived isotopes. To avoid these limitations, a new type of gas stopper is being developed at the NSCL/MSU. The new system is based on a cyclotron-type magnet with a stopping chamber filled with Helium buffer gas at low pressure. RF-guiding techniques are used to extract the ions. The space charge effects are considerably reduced by the large volume and due to a separation between the stopping region and the region of highest ionization. Cyclotron gas stopper systems of different sizes and with different magnetic field strengths and field shapes are presently investigated.

  1. MODELING OF FLOW AND TRANSPORT INDUCED BY PRODUCTION OF HYDROFRACTURE-STIMULATED GAS WELLS NEAR THE RULISON NUCLEAR TEST

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, Rex A. [Navarro Research and Engineering; Cooper, Clay [Desert Research Inst. (DRI), Reno, NV (United States); Falta, Ronald [Clemson Univ., SC (United States)

    2012-09-17

    The Piceance Basin in western Colorado contains significant reserves of natural gas in poorly connected, low-permeability (tight) sandstone lenses of the Mesaverde Group. The ability to enhance the production of natural gas in this area has long been a goal of the oil and gas industry. The U.S. Atomic Energy Commission, a predecessor agency to the U.S. Department of Energy (DOE) and the U.S. Nuclear Regulatory Commission, participated in three tests using nuclear detonations to fracture tight formations in an effort to enhance gas production. The tests were conducted under Project Plowshare, a program designed to identify peaceful, beneficial uses for nuclear devices. The first, Project Gasbuggy, was conducted in 1967 in the San Juan Basin of New Mexico. The two subsequent tests, Project Rulison in 1969 and Project Rio Blanco in 1973, were in the Piceance Basin. The ability to enhance natural gas production from tight sands has become practical through advances in hydraulic fracturing technology (hydrofracturing). This technology has led to an increase in drilling activity near the Rulison site, raising concerns that contamination currently contained in the subsurface could be released through a gas well drilled too close to the site. As wells are drilled nearer the site, the DOE Office of Legacy Management has taken the approach outlined in the June 2010 Rulison Path Forward document (DOE 2010), which recommends a conservative, staged approach to gas development. Drillers are encouraged to drill wells in areas with a low likelihood of encountering contamination (both distance and direction from the detonation zone are factors) and to collect data from these wells prior to drilling nearer the site’s 40 acre institutional control boundary (Lot 11). Previous modeling results indicate that contamination has been contained within Lot 11 (Figure 1). The Path Forward document couples the model predictions with the monitoring of gas and produced water from the gas wells

  2. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  3. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiali; Yu, Xinhai, E-mail: yxhh@ecust.edu.cn; Tu, Shan-Tung; Wang, Zhengdong [Key Laboratory of Pressure Systems and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China); Wang, Zhenyu [Integrated Micro & Nano System Engineering Center, School of Software and Microelectronics at Wuxi, Peking University (China)

    2016-04-15

    The effects of the gas pressure (p{sub g}), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d{sub h} = 1000 μm) driven at constant voltage loading on the drive electrode (V{sub rf}) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p{sub g} increased, the maximum electron (n{sub e}) or ion density (n{sub Ar+}) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ{sub SEE-e}). The peak n{sub e} and n{sub Ar+} were not a monotonic function of p{sub g}, resulting from the two conflicting effects of p{sub g} on n{sub e} and n{sub Ar+}. The impact of ions on the electrode was enhanced when p{sub g} increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p{sub g}. The effects of t on the peaks and distributions of n{sub e} and n{sub Ar+} were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p{sub g} of 800 Pa and V{sub rf} of 180 V. The Au vapor addition increased the peaks of n{sub e} and n{sub Ar+}, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  4. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    International Nuclear Information System (INIS)

    Tang, Jiali; Yu, Xinhai; Tu, Shan-Tung; Wang, Zhengdong; Wang, Zhenyu

    2016-01-01

    The effects of the gas pressure (p_g), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d_h = 1000 μm) driven at constant voltage loading on the drive electrode (V_r_f) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p_g increased, the maximum electron (n_e) or ion density (n_A_r_+) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ_S_E_E_-_e). The peak n_e and n_A_r_+ were not a monotonic function of p_g, resulting from the two conflicting effects of p_g on n_e and n_A_r_+. The impact of ions on the electrode was enhanced when p_g increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p_g. The effects of t on the peaks and distributions of n_e and n_A_r_+ were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p_g of 800 Pa and V_r_f of 180 V. The Au vapor addition increased the peaks of n_e and n_A_r_+, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  5. A Buffer Management Issue in Designing SSDs for LFSs

    Science.gov (United States)

    Kim, Jaegeuk; Seol, Jinho; Maeng, Seungryoul

    This letter introduces a buffer management issue in designing SSDs for log-structured file systems (LFSs). We implemented a novel trace-driven SSD simulator in SystemC language, and simulated several SSD architectures with the NILFS2 trace. From the results, we give two major considerations related to the buffer management as follows. (1) The write buffer is used as a buffer not a cache, since all write requests are sequential in NILFS2. (2) For better performance, the main architectural factor is the bus bandwidth, but 332MHz is enough. Instead, the read buffer makes a key role in performance improvement while caching data. To enhance SSDs, accordingly, it is an effective way to make efficient read buffer management policies, and one of the examples is tracking the valid data zone in NILFS2, which can increase the data hit ratio in read buffers significantly.

  6. Magnetorheological elastomer and its application on impact buffer

    International Nuclear Information System (INIS)

    Fu, J; Yu, M; Zhu, L X; Dong, X M

    2013-01-01

    In this study, a new magnetorheological elastomer (MRE) based buffer is proposed and its vibration isolation performance is investigated. The MRE buffer with a compact structure is first designed in order to accomplish the maximization of the variable stiffness range. The working characteristics of the MRE buffer are then measured and the model of MRE is established. On the basis of the experimental data, the control model of the MRE buffer is also formulated. A two-degree-of-freedom dynamic model with an MRE buffer is then developed. An intelligent control strategy, human simulated intelligent control (HSIC), is proposed to reduce the impact during the drop crash. Finally, the proposed MRE buffer and controller are validated numerically and experimentally. The results show that the proposed MRE buffer and the control strategy can reduce the impact acceleration effectively.

  7. High resolution temperature mapping of gas turbine combustor simulator exhaust with femtosecond laser induced fiber Bragg gratings

    Science.gov (United States)

    Walker, Robert B.; Yun, Sangsig; Ding, Huimin; Charbonneau, Michel; Coulas, David; Lu, Ping; Mihailov, Stephen J.; Ramachandran, Nanthan

    2017-04-01

    Femtosecond infrared (fs-IR) laser written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme sensing. Such conditions are inherent in advanced gas turbine engines under development to reduce greenhouse gas emissions; and the ability to measure temperature gradients in these harsh environments is currently limited by the lack of sensors and controls capable of withstanding the high temperature, pressure and corrosive conditions present. This paper discusses fabrication and deployment of several fs-IR written FBG arrays, for monitoring exhaust temperature gradients of a gas turbine combustor simulator. Results include: contour plots of measured temperature gradients, contrast with thermocouple data.

  8. Buffer layers and articles for electronic devices

    Science.gov (United States)

    Paranthaman, Mariappan P.; Aytug, Tolga; Christen, David K.; Feenstra, Roeland; Goyal, Amit

    2004-07-20

    Materials for depositing buffer layers on biaxially textured and untextured metallic and metal oxide substrates for use in the manufacture of superconducting and other electronic articles comprise RMnO.sub.3, R.sub.1-x A.sub.x MnO.sub.3, and combinations thereof; wherein R includes an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and A includes an element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Ra.

  9. Shock buffer for nuclear control element assembly

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1977-01-01

    A shock buffer for a control element assembly in a nuclear reactor is described, comprising a piston and a cylinder. The piston is affixed to and extends upward from the control rod guide structure; the cylinder is supported by the upper portion of the control element assembly and is vertically oriented with open end downward for receiving the piston. Coolant liquid normally has free access to the cylinder. The piston displaces liquid from the cylinder when inserted, thereby decelerating the control element assembly near its lower extent of travel. (LL)

  10. Physiological gas exchange mapping of hyperpolarized 129 Xe using spiral-IDEAL and MOXE in a model of regional radiation-induced lung injury.

    Science.gov (United States)

    Zanette, Brandon; Stirrat, Elaine; Jelveh, Salomeh; Hope, Andrew; Santyr, Giles

    2018-02-01

    To map physiological gas exchange parameters using dissolved hyperpolarized (HP) 129 Xe in a rat model of regional radiation-induced lung injury (RILI) with spiral-IDEAL and the model of xenon exchange (MOXE). Results are compared to quantitative histology of pulmonary tissue and red blood cell (RBC) distribution. Two cohorts (n = 6 each) of age-matched rats were used. One was irradiated in the right-medial lung, producing regional injury. Gas exchange was mapped 4 weeks postirradiation by imaging dissolved-phase HP 129 Xe using spiral-IDEAL at five gas exchange timepoints using a clinical 1.5 T scanner. Physiological lung parameters were extracted regionally on a voxel-wise basis using MOXE. Mean gas exchange parameters, specifically air-capillary barrier thickness (δ) and hematocrit (HCT) in the right-medial lung were compared to the contralateral lung as well as nonirradiated control animals. Whole-lung spectroscopic analysis of gas exchange was also performed. δ was significantly increased (1.43 ± 0.12 μm from 1.07 ± 0.09 μm) and HCT was significantly decreased (17.2 ± 1.2% from 23.6 ± 1.9%) in the right-medial lung (i.e., irradiated region) compared to the contralateral lung of the irradiated rats. These changes were not observed in healthy controls. δ and HCT correlated with histologically measured increases in pulmonary tissue heterogeneity (r = 0.77) and decreases in RBC distribution (r = 0.91), respectively. No changes were observed using whole-lung analysis. This work demonstrates the feasibility of mapping gas exchange using HP 129 Xe in an animal model of RILI 4 weeks postirradiation. Spatially resolved gas exchange mapping is sensitive to regional injury between cohorts that was undetected with whole-lung gas exchange analysis, in agreement with histology. Gas exchange mapping holds promise for assessing regional lung function in RILI and other pulmonary diseases. © 2017 The Authors. Medical Physics published by Wiley

  11. High-resolution electron microscopy study of Ni81Fe19 film with Co33Cr67 buffer layer

    International Nuclear Information System (INIS)

    Xu, Q.Y.; Wang, Z.M.; Shen, F.; Du, Y.W.; Zhang, Z.

    2003-01-01

    The anisotropic magnetoresistance (AMR) in permalloy Ni 81 Fe 19 film deposited on a 1.2 nm Co 33 Cr 67 buffer layer was significantly enhanced. The high-resolution electron microscopy was used to study the microstructure of Ni 81 Fe 19 film with and without Co 33 Cr 67 buffer layer. It was found that Co 33 Cr 67 buffer layer can induce good (1 1 1) texture, while without Co 33 Cr 67 buffer layer, Ni 81 Fe 19 film show randomly oriented grain structure. The Δρ/ρ enhancement is attributed to the decrease in the resistivity ρ of the Ni 81 Fe 19 film due to the formation of the large (1 1 1) textured grains in Ni 81 Fe 19 film with Co 33 Cr 67 buffer layer. However, the surface roughness of substrate may limit the (1 1 1) textured grain size and induce additional grain boundaries in Ni 81 Fe 19 film with Co 33 Cr 67 buffer layer, limit the enhancement of the AMR effect

  12. Nanosecond Nd-YAG laser induced plasma emission characteristics in low pressure CO{sub 2} ambient gas for spectrochemical application on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Lie, Zener Sukra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Kagawa, Kiichiro [Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia)

    2015-08-28

    An experimental study is conducted on the possibility and viability of performing spectrochemical analysis of carbon and other elements in trace amount in Mars, in particular, the clean detection of C, which is indispensible for tracking the sign of life in Mars. For this study, a nanosecond Nd-YAG laser is employed to generate plasma emission from a pure copper target in CO{sub 2} ambient gas of reduced pressure simulating the atmospheric condition of Mars. It is shown that the same shock wave excitation mechanism also works this case while exhibiting remarkably long cooling stage. The highest Cu emission intensities induced by 4 mJ laser ablation energy is attained in 600 Pa CO{sub 2} ambient gas. Meanwhile the considerably weaker carbon emission from the CO{sub 2} gas appears relatively featureless over the entire range of pressure variation, posing a serious problem for sensitive trace analysis of C contained in a solid sample. Our time resolved intensity measurement nevertheless reveals earlier appearance of C emission from the CO{sub 2} gas with a limited duration from 50 ns to 400 ns after the laser irradiation, well before the initial appearance of the long lasting C emission from the solid target at about 1 μs, due to the different C-releasing processes from their different host materials. The unwanted C emission from the ambient gas can thus be eliminated from the detected spectrum by a proper time gated detection window. The excellent spectra of carbon, aluminum, calcium, sodium, hydrogen, and oxygen obtained from an agate sample are presented to further demonstrate and verify merit of this special time gated LIBS using CO{sub 2} ambient gas and suggesting its viability for broad ranging in-situ applications in Mars.

  13. One-Way Flow of a Rarefied Gas Induced in a Circular Pipe with a Periodic Temperature Distribution

    National Research Council Canada - National Science Library

    Aoki, K

    2000-01-01

    The steady behavior of a rarefied gas in a circular pipe with a saw-like temperature distribution increasing and decreasing periodically in the direction of the pipe axis is investigated numerically...

  14. Influence of surrounding gas, composition and pressure on plasma plume dynamics of nanosecond pulsed laser-induced aluminum plasmas

    Directory of Open Access Journals (Sweden)

    Mahmoud S. Dawood

    2015-10-01

    Full Text Available In this article, we present a comprehensive study of the plume dynamics of plasmas generated by laser ablation of an aluminum target. The effect of both ambient gas composition (helium, nitrogen or argon and pressure (from ∼5 × 10−7 Torr up to atmosphere is studied. The time- and space- resolved observation of the plasma plume are performed from spectrally integrated images using an intensified Charge Coupled Device (iCCD camera. The iCCD images show that the ambient gas does not significantly influence the plume as long as the gas pressure is lower than 20 Torr and the time delay below 300 ns. However, for pressures higher than 20 Torr, the effect of the ambient gas becomes important, the shortest plasma plume length being observed when the gas mass species is highest. On the other hand, space- and time- resolved emission spectroscopy of aluminum ions at λ = 281.6 nm are used to determine the Time-Of-Flight (TOF profiles. The effect of the ambient gas on the TOF profiles and therefore on the propagation velocity of Al ions is discussed. A correlation between the plasma plume expansion velocity deduced from the iCCD images and that estimated from the TOF profiles is presented. The observed differences are attributed mainly to the different physical mechanisms governing the two diagnostic techniques.

  15. Quantitative evaluation of the effect of buffer pressure on well output

    Energy Technology Data Exchange (ETDEWEB)

    Kobrushko, A T

    1980-01-01

    In the examples of the Pashninskiy and the Usinskiy fields of the Komi ASSR, a method is presented for determining the possible increase in output of a gusher well on decrease in the buffer pressure. A quantitative evaluation of this increase is presented. The essence of the method is construction of a nomogram for characteristics of a gusher lifter and indicator diagrams of the wells combined in one figure. Mutual intersection of the characteristics and diagrams corresponds to the steady-state operating mode of the bed-well system. Cases are examined of productivity 10, 25, 50 and 100 m/sup 3//day of the MPa for the Pashninskiy and 25, 50, 102 and 200 m/sup 3//day of the MPa for the Usinskiy fields. Despite the broad range of well productivity, and also the significant difference in fields according to gushing conditions, increase of the well output for 0.1 MPa of decrease in buffer pressure differs little. In the interval of buffer pressures 2.00.5 MPa, the specific increase of output from decrease in buffer pressure is very significant and is 7-10 m/sup 3//day. The findings convincingly proved the expediency of using systems of oil and gas recovery at new fields with possibly low pressure in the pipelines.

  16. Time-related Changes in pH, Buffering Capacity and Phosphate and Urea Concentration of Stimulated Saliva.

    Science.gov (United States)

    Vuletic, Lea; Peros, Kristina; Spalj, Stjepan; Rogic, Dunja; Alajbeg, Ivan

    2014-01-01

    To quantify changes in pH, buffering capacity and hydrogen carbonate, phosphate, protein and urea concentrations of stimulated saliva which occur during a 30-min measurement delay after saliva collection. The correlation between time-related chemical changes and changes of salivary pH and buffering capacity was assessed in order to explain the observed changes in salivary pH and buffering capacity. Stimulated saliva samples were collected from 30 volunteers after inducing salivation by chewing a piece of parafilm. Measurements of salivary variables were made immediately after saliva collection and again 30 min later, during which time the specimens were exposed to the atmosphere in collection cups at room temperature. Postponement of measurements resulted in a significant increase in pH and a significant decrease of buffering capacity, phosphate and urea concentration. The results suggest that the time-related pH increase could primarily be attributed to loss of dissolved carbon dioxide from saliva, and confirm the importance of hydrogen carbonate in the neutralisation of hydrogen ions, but they do not support the principle of catalysed phase-buffering for the hydrogen carbonate buffer system in saliva. A decrease in phosphate and urea concentration affects salivary buffering capacity. This study emphasises the importance of the standardisation of measurement time when measuring salivary pH, buffering capacity, phosphate and urea concentrations following the collection of saliva in order to obtain comparable results. It also provides a partial explanation of the mechanisms underlying the observed changes of pH and buffering capacity over time.

  17. Clad buffer rod sensors for liquid metals

    International Nuclear Information System (INIS)

    Jen, C.-K.; Ihara, I.

    1999-01-01

    Clad buffer rods, consisting of a core and a cladding, have been developed for ultrasonic monitoring of liquid metal processing. The cores of these rods are made of low ultrasonic-loss materials and the claddings are fabricated by thermal spray techniques. The clad geometry ensures proper ultrasonic guidance. The lengths of these rods ranges from tens of centimeters to 1m. On-line ultrasonic level measurements in liquid metals such as magnesium at 700 deg C and aluminum at 960 deg C are presented to demonstrate their operation at high temperature and their high ultrasonic performance. A spherical concave lens is machined at the rod end for improving the spatial resolution. High quality ultrasonic images have been obtained in the liquid zinc at 600 deg C. High spatial resolution is needed for the detection of inclusions in liquid metals during processing. We also show that the elastic properties such as density, longitudinal and shear wave velocities of liquid metals can be measured using a transducer which generates and receives both longitudinal and shear waves and is mounted at the end of a clad buffer rod. (author)

  18. Unsaturated hydraulic property of buffer material

    International Nuclear Information System (INIS)

    Suzuki, Hideaki; Fujita, Tomoo

    1999-09-01

    After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanism, infiltration of groundwater from the surrounding rock into the EBS, generation of swelling pressure in the buffer due to water infiltration and the stress imposed by the overburden pressure. These phenomena are not all independent, but can be strongly influenced by, and coupled with, each other. Evaluating these coupled thermo-hydro-mechanical phenomena is important in order to clarify the initial transient behavior of the engineered barrier system within the near-field. This report describes the results on measurement of chemical potential, water diffusivity, and thermal water diffusivity of bentonite that is considered as a candidate material of buffer and on comparison between measurements and theoretical studies for these properties. The following results are identified; (l) The hysteresis of chemical potential in wet and dry conditions for compacted bentonite is not shown clearly. The chemical potential depends on temperature and amount of montmorillonite. When chemical potential of compacted bentonite is zero, the specimen is saturated. The van Genuchten model is applicable to the measured chemical potential of compacted bentonite. (2) The Darcy's law and Philip and de Vries model are applicable to the measured water diffusivity and thermal water diffusivity of compacted bentonite. (author)

  19. Ammonia gas transport and reactions in unsaturated sediments: Implications for use as an amendment to immobilize inorganic contaminants

    International Nuclear Information System (INIS)

    Zhong, L.; Szecsody, J.E.; Truex, M.J.; Williams, M.D.; Liu, Y.

    2015-01-01

    Highlights: • Ammonia transport can be predicted from gas movement and equilibrium partitioning. • Ammonia diffusion rate in unsaturated sediment is a function of water contents. • High pH induced by ammonia causes mineral dissolution and sequential precipitation. • Ammonia treatment effectively immobilized uranium from contaminated sediments. - Abstract: Use of gas-phase amendments for in situ remediation of inorganic contaminants in unsaturated sediments of the vadose zone may be advantageous, but there has been limited development and testing of gas remediation technologies. Treatment with ammonia gas has a potential for use in treating inorganic contaminants (such as uranium) because it induces a high pore-water pH, causing mineral dissolution and subsequent formation of stable precipitates that decrease the mobility of some contaminants. For field application of this treatment, further knowledge of ammonia transport in porous media and the geochemical reactions induced by ammonia treatment is needed. Laboratory studies were conducted to support calculations needed for field treatment design, to quantify advective and diffusive ammonia transport in unsaturated sediments, to evaluate inter-phase (gas/sediment/pore water) reactions, and to study reaction-induced pore-water chemistry changes as a function of ammonia delivery conditions, such as flow rate, gas concentration, and water content. Uranium-contaminated sediment was treated with ammonia gas to demonstrate U immobilization. Ammonia gas quickly partitions into sediment pore water and increases the pH up to 13.2. Injected ammonia gas advection front movement can be reasonably predicted by gas flow rate and equilibrium partitioning. The ammonia gas diffusion rate is a function of the water content in the sediment. Sodium, aluminum, and silica pore-water concentrations increase upon exposure to ammonia and then decline as aluminosilicates precipitate when the pH declines due to buffering. Up to 85% of

  20. The use of 0.01M phosphate buffered saline as detection buffer for ...

    African Journals Online (AJOL)

    Insufficient supply of manufacture's buffers/diluents in relation to the number of strips per kit has been found to have negative impact on patients' results. Some laboratories personnel tend to use diluents from other rapid tests manufacturers such as Bioline, Unigold as well as malaria rapid diagnostic test (MRDT). This study ...

  1. Vegetative buffer strips for reducing herbicide transport in runoff: effects of buffer width, vegetation, and season

    Science.gov (United States)

    The effect of vegetative buffer strip (VBS) width, vegetation, and season of the year on herbicide transport in runoff has not been well documented for runoff prone soils. A multi-year replicated plot-scale study was conducted on an eroded claypan soil with the following objectives: 1) assess the ef...

  2. Detection of radiation-induced hydrocarbons in irradiated fish and prawns by means of on-line coupled liquid chromatography-gas chromatography

    International Nuclear Information System (INIS)

    Schulzki, G.; Spiegelberg, A.; Bogl, K.W.; Schreiberg, G.A.

    1997-01-01

    Radiation-induced hydrocarbons were analyzed in a fatty (halibut) and a lean fish (cod) as well as in a prawn species by on-line coupled liquid chromatography (LC) -gas chromatography (GC) combined with mass spectrometry. In irradiated halibut which is known to contain mainly saturated and monounsaturated fatty acids, all expected radiolytic alkanes, alkenes, and alkadienes could be detected. The yields of the C(n-1) and C(n-2:1) hydrocarbons were comparable to those found in irradiated lipids of terrestrial animals and plants. However, in cod and prawns which contain high levels of polyunsaturated fatty acids (PUFA), the C(n-1) hydrocarbons were found in concentrations which were up to 10 times higher whereas the C(n-2:1) products were again comparable to those of terrestrial animals and plants. The identification of radiation-induced hydrocarbons in fish lipids was achieved by transfer of the hydrocarbons from the LC column to the gas chromatographic column in fractions differing in their degree of unsaturation. For the first time, radiation-induced hydrocarbons with more than four double bonds generated from polyunsaturated fatty acids (20:4 omega 6 and 20:5 omega 3) could be identified

  3. Activation of a Ca-bentonite as buffer material

    Science.gov (United States)

    Huang, Wei-Hsing; Chen, Wen-Chuan

    2016-04-01

    Swelling behavior is an important criterion in achieving the low-permeability sealing function of buffer material. A potential buffer material may be used for radioactive waste repository in Taiwan is a locally available clayey material known as Zhisin clay, which has been identified as a Ca-bentonite. Due to its Ca-based origin, Zhisin was found to exhibit swelling capacity much lower than that of Na-bentonite. To enhance the swelling potential of Zhisin clay, a cation exchange process by addition of Na2CO3 powder was introduced in this paper. The addition of Na2CO3 reagent to Zhisin clay, in a liquid phase, caused the precipitation of CaCO3 and thereby induced a replacement of Ca2+ ions by Na+ ions on the surface of bentonite. Characterization test conducted on Zhisin clay includes chemical analysis, cation exchange capacity, X-ray diffraction, and thermogravimetry (TG). Free-swelling test apparatus was developed according to International Society of Rock Mechanics recommendations. A series of free-swelling tests were conducted on untreated and activated specimens to characterize the effect of activation on the swelling capacity of Zhisin clay. Efforts were made to determine an optimum dosage for the activation, and to evaluate the aging effect. Also, the activated material was evaluated for its stability in various hydrothermal conditions for potential applications as buffer material in a repository. Experimental results show that Na2CO3-activated Zhisin clay is superior in swelling potential to untreated Zhisin clay. Also, there exists an optimum amount of activator in terms of improvements in the swelling capacity. A distinct time-swell relationship was discovered for activated Zhisin clay. The corresponding mechanism refers to exchange of cations and breakdown of quasi-crystal, which results in ion exchange hysteresis of Ca-bentonite. Due to the ion exchange hysteresis, activated bentonite shows a post-rise time-swell relationship different than the sigmoid

  4. Chemical buffering in natural and engineered barrier systems: Thermodynamic constraints and performance assessment consequences

    International Nuclear Information System (INIS)

    Arthur, R.C.; Wei Zhou

    2000-12-01

    proportional to the buffer intensity. For conditions considered in the bentonite model, calculated front velocities vary from 6.6 x 10 -2 to 6.6 x 10 -5 mm/yr, corresponding to values of the buffer intensity between 1 and 1000 meq/l, respectively. Corresponding travel times for the front to migrate from the buffer-host rock interface to the buffer-canister boundary range from about 5 x 10 3 to 5 x 10 6 years. For conditions considered in the farfield model, the estimated pH-front velocity is about 5.7 x 10 -1 mm/yr, or a factor 5.7 x 10 -5 slower than the assumed Darcy flow velocity of 10 m/yr. The corresponding time for the front to migrate 500 m (e.g., from the ground surface to the depth of a KBS-3 repository) is about 9 x 10 5 years. With the preliminary nature of these results in mind, we conclude that chemical buffering may play an important role in determining the performance of a KBS-3 repository. For example, periods of time that are significant in relation to performance assessment time scales may be required for a pH front, and perhaps other types of fronts, to migrate from the buffer host rock boundary to the buffer-canister boundary (just 35 cm in width). This implies that the KBS-3 near field could in effect be decoupled from the far field, thus minimizing effects on repository performance of time-dependent variations in the geosphere. Similarly, buffering may strongly resist changes in the chemistry of the geosphere, which could be caused, for example, by future variations in climate or other natural or man-induced processes

  5. Buffer Sizing in 802.11 Wireless Mesh Networks

    KAUST Repository

    Jamshaid, Kamran; Shihada, Basem; Xia, Li; Levis, Philip

    2011-01-01

    We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this results in large queueing delays. Such delays may affect TCP stability characteristics, and also increase queueing delays for other flows (including real-time flows) sharing the buffer. In this paper we propose sizing link buffers collectively for a set of nodes within mutual interference range called the 'collision domain'. We aim to provide a buffer just large enough to saturate the available capacity of the bottleneck collision domain that limits the carrying capacity of the network. This neighborhood buffer is distributed over multiple nodes that constitute the network bottleneck; a transmission by any of these nodes fully utilizes the available spectral resource for the duration of the transmission. We show that sizing routing buffers collectively for this bottleneck allows us to have small buffers (as low as 2 - 3 packets) at individual nodes without any significant loss in network utilization. We propose heuristics to determine these buffer sizes in WMNs. Our results show that we can reduce the end-to-end delays by 6× to 10× at the cost of losing roughly 5% of the network capacity achievable with large buffers.

  6. Buffer Sizing in 802.11 Wireless Mesh Networks

    KAUST Repository

    Jamshaid, Kamran

    2011-10-01

    We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this results in large queueing delays. Such delays may affect TCP stability characteristics, and also increase queueing delays for other flows (including real-time flows) sharing the buffer. In this paper we propose sizing link buffers collectively for a set of nodes within mutual interference range called the \\'collision domain\\'. We aim to provide a buffer just large enough to saturate the available capacity of the bottleneck collision domain that limits the carrying capacity of the network. This neighborhood buffer is distributed over multiple nodes that constitute the network bottleneck; a transmission by any of these nodes fully utilizes the available spectral resource for the duration of the transmission. We show that sizing routing buffers collectively for this bottleneck allows us to have small buffers (as low as 2 - 3 packets) at individual nodes without any significant loss in network utilization. We propose heuristics to determine these buffer sizes in WMNs. Our results show that we can reduce the end-to-end delays by 6× to 10× at the cost of losing roughly 5% of the network capacity achievable with large buffers.

  7. Detection and identification of radiation induced hydrocarbons in meets with the use of gas chromatography as one of methods for the detection of irradiated food

    International Nuclear Information System (INIS)

    Lehner, K.; Stachowicz, W.

    2000-01-01

    Results of the determination of the content of radiation induced hydrocarbons in meat samples (chicken, pork, beef) as well as proportion between the concentration of individual hydrocarbons in relation to the content of fatty acids in a given product are presented. The measurements have been done with the use of a Perkin Elmer model 8700 gas chromatograph equipped with a FID detector. The present study is a preliminary work on the implementation of a routine method for the detection of irradiation in foods that contain fats. (author)

  8. Collision-induced dissociation of noncovalent complexes between vancomycin antibiotics and peptide ligand stereoisomers: evidence for molecular recognition in the gas phase

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J. D.; Delforge, D; Remacle, J

    1999-01-01

    In solution, the antibiotics of the vancomycin group bind stereospecifically to peptides with the C-terminal sequence: -L-Lys-D-Ala-D-Ala, Substitution by a L-Ala at either of the two C-terminal residues causes a dramatic decrease in the binding affinity to the antibiotics. This solution behavior...... is clearly reflected in electrospray ionization (ESI) mass spectra obtained from equimolar mixtures of an antibiotic, an isotopically labelled peptide ligand and an unlabelled peptide stereoisomer. Using collision-induced dissociation (CID) we have probed the gas phase stability of isomeric (1:1) noncovalent...

  9. Quantification of potential macroseismic effects of the induced seismicity that might result from hydraulic fracturing for shale gas exploitation in the UK

    OpenAIRE

    Westaway, Robert; Younger, Paul L.

    2014-01-01

    The furore that has arisen in the UK over induced microseismicity from ‘fracking’ for shale gas development, which has resulted in ground vibrations strong enough to be felt, requires the urgent development of an appropriate regulatory framework. We suggest that the existing regulatory limits applicable to quarry blasting (i.e. peak ground velocities (PGV) in the seismic wavefield incident on any residential property of 10 mm s−1 during the working day, 2 mm s−1 at night, and 4.5 mm s−11 at o...

  10. Experiments on thermal conductivity in buffer materials for geologic repository

    International Nuclear Information System (INIS)

    Kanno, T.; Yano, T.; Wakamatsu, H.; Matsushima, E.

    1989-01-01

    Engineered barriers for geologic disposal for HLW are planned to consist of canister, overpack and buffer elements. One of important physical characteristics of buffer materials is determining temperature profiles within the near field in a repository. Buffer materials require high thermal conductivity to disperse radiogenic heat away to the host rock. As the buffer materials, compacted blocks of the mixture of sodium bentonite and sand have been the most promising candidate in some countries, e.g. Sweden, Switzerland and Japan. The authors have been carrying out a series of thermal dispersion experiments to evaluate thermal conductivity of bentonite/quartz sand blocks. In this study, the following two factors considered to affect thermal properties of the near field were examined: effective thermal conductivities of buffer materials, and heat transfer characteristics of the gap between overpack and buffer materials

  11. Moisture buffering capacity of highly absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Cerolini, S.; D' Orazio, M.; Stazi, A. [Department of Architecture, Construction and Structures (DACS), Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy); Di Perna, C. [Department of Energetics, Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy)

    2009-02-15

    This research investigates the possibility to use highly absorbing materials to dampen indoor RH% variations. The practical MBV of sodium polyacrylate, cellulose-based material, perlite and gypsum is evaluated for a daily cyclic exposure that alternates high (75%) and low (33%) RH% levels for 8 h and 16 h, respectively. The adjustment velocity to RH% variations and the presence of hysteretic phenomena are also presented. The cellulose-based material proves to be the most suitable for moisture buffering applications. Starting from this material's properties, the effect of thickness, vapour resistance factor ({mu}) and mass surface exchange coefficient (Z{sub v}) on sorption capacity is evaluated by the use of a numerical model. (author)

  12. A high capacity FASTBUS multiple event buffer

    International Nuclear Information System (INIS)

    Appel, J.A.; Farr, W.D.; Kaplan, D.M.; Levit, L.B.; Napier, T.M.

    1985-01-01

    We have developed a front-end data acquisition and event buffering memory. This single-width FASTBUS module has a capacity of 256K X 32 bits plus parity. The module is dual ported, and its front panel ECLport accepts data at up to 20 MB/sec. It may also be written to and read from as a standard FASTBUS Slave. The module records events as variable length records. Each record is accepted or rejected via front panel control signal. Circuitry to automate FASTBUS record readout and record skip is provided. In its ''linear'' mode, the module may be used as a single pass list. Alternatively, in the ''circular'' mode, the module's internal read pointer can follow its write pointer continuously around the memory. Circular mode is well suited to handling of a continuous data stream. Modules may be linked for larger memory capacity

  13. Buffer mass test - Heater design and operation

    International Nuclear Information System (INIS)

    Nilsson, J.; Ramqvist, G.; Pusch, R.

    1984-06-01

    The nuclear waste is assumed to be contained in cylindrical metal canisters which will be inserted in deposition holes. Heat is generated as a result of the continuing decay of the radioactive waste and in the Buffer Mass Test (BMT) the heat flux expected from such canisters was simulated by the use of six electric heaters. the heaters were constructed partly of aluminium and partly of stainless steel. They are 1520 mm in length and 380 mm in diameter, and give a maximum power output of 3000 W. The heater power can be monitored by panel meters coupled to a computer-based data acquisition system. Both the heater and the control system were manufactured with a high degree of redundancy in case of component failure. This report describes the design, construction, testing, installation and necessary tools for heater installation and dismantling operation. (author)

  14. A study on manufacturing and construction method of buffer

    International Nuclear Information System (INIS)

    Chijimatsu, Masakazu; Sugita, Yutaka; Amemiya, Kiyoshi

    1999-09-01

    As an engineered barrier system in the geological disposal of high-level waste, multibarrier system is considered. Multibarrier system consists of the vitrified waste, the overpack and the buffer. Bentonite is one of the potential material as the buffer because of its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. In order to evaluate the functions of buffer, a lot of experiments has been conducted. The evaluations of these functions are based on the assumption that the buffer is emplaced or constructed in the disposal tunnel (or disposal pit) properly. Therefore, it is necessary to study on the manufacturing / construction method of buffer. As the manufacturing / construction technology of the buffer, the block installation method and in-situ compaction method, etc, are being investigated. The block installation method is to emplace the buffer blocks manufactured in advance at the ground facility, and construction processes of the block installation method at the underground will be simplified compared with the in-situ compaction method. On the other hand, the in-situ compaction method is to introduce the buffer material with specified water content into the disposal tunnel and to make the buffer with high density at the site using a compaction machine. In regard to the in-situ compaction method, it is necessary to investigate the optimum finished thickness of one layer because it is impossible to construct the buffer at one time. This report describes the results of compaction property test and the summary of the past investigation results in connection with the manufacturing / construction method. Then this report shows the construction method that will be feasible in the actual disposal site. (J.P.N.)

  15. Application of capillary gas chromatography-mass spectrometry to chemical characterization of radiation-induced base damage of DNA: implications for assessing DNA repair processes

    International Nuclear Information System (INIS)

    Dizdaroglu, M.

    1985-01-01

    The application of capillary gas chromatography-mass spectrometry (GC-MS) to the chemical characterization of radiation-induced base products of calf thymus DNA is presented. Samples of calf thymus DNA irradiated in N 2 O-saturated aqueous solution were hydrolyzed with HCOOH, trimethylsilylated, and subjected to GC-MS analysis using a fused-silica capillary column. Hydrolysis conditions suitable for the simultaneous analysis of the radiation-induced products of all four DNA bases in a single run were determined. The trimethylsilyl derivatives of these products had excellent GC properties and easily interpretable mass spectra; an intense molecular ion (M+.) and a characteristic (M-CH 3 )+ ion were observed. The complementary use of t-butyldimethylsilyl derivatives was also demonstrated. These derivatives provided an intense characteristic (M-57)+ ion, which appeared as either the base peak or the second most intense ion in the spectra. All mass spectra obtained are discussed

  16. Moisture Buffer Effect and its Impact on Indoor Environment

    DEFF Research Database (Denmark)

    Zhang, Mingjie; Qin, Menghao; Chen, Zhi

    2017-01-01

    The moisture buffer effect of building materials may have great influence on indoor hygrothermal environment. In order to characterize the moisture buffering ability of materials, the basic concept of moisture buffer value (MBV) is adopted. Firstly, a theoretical correction factor is introduced...... in this paper. The moisture uptake/release by hygroscopic materials can be calculated with the factor and the basic MBV. Furthermore, the validation of the correction factor is carried out. The impact of moisture buffering on indoor environment is assessed by using numerical simulations. The results show...

  17. Effects of node buffer and capacity on network traffic

    International Nuclear Information System (INIS)

    Ling Xiang; Ding Jian-Xun; Hu Mao-Bin

    2012-01-01

    In this paper, we study the optimization of network traffic by considering the effects of node buffer ability and capacity. Two node buffer settings are considered. The node capacity is considered to be proportional to its buffer ability. The node effects on network traffic systems are studied with the shortest path protocol and an extension of the optimal routing [Phys. Rev. E 74 046106 (2006)]. In the diagrams of flux—density relationships, it is shown that a nodes buffer ability and capacity have profound effects on the network traffic

  18. Back contact buffer layer for thin-film solar cells

    Science.gov (United States)

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  19. Solubilization of proteins: the importance of lysis buffer choice.

    Science.gov (United States)

    Peach, Mandy; Marsh, Noelle; Miskiewicz, Ewa I; MacPhee, Daniel J

    2015-01-01

    The efficient extraction of proteins of interest from cells and tissues is not always straightforward. Here we demonstrate the differences in extraction of the focal adhesion protein Kindlin-2 from choriocarcinoma cells using NP-40 and RIPA lysis buffer. Furthermore, we demonstrate the use of a more denaturing urea/thiourea lysis buffer for solubilization, by comparing its effectiveness for solubilization of small heat-shock proteins from smooth muscle with the often utilized RIPA lysis buffer. Overall, the results demonstrate the importance of establishing the optimal lysis buffer for specific protein solubilization within the experimental workflow.

  20. How Do Stream Buffers Reduce the Offsite Impact of Pollution?

    OpenAIRE

    Easton, Zachary M.

    2012-01-01

    Summarizes the importance of buffers to reduce pollution and specifically examines where they can be used, how they work, their limitations, required maintenance, performance levels, and expected cost.

  1. Effect of Buffer Bow Structure in Ship-Ship Collision

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Endo, Hisayoshi; Pedersen, Preben Terndrup

    2008-01-01

    tankers, the introduction of buffer bulbous bows has been proposed. Relatively soft buffer bows absorb part of the kinetic energy of the striking ship before penetrating the inner hull of the struck vessel. The purpose of the present paper is to verify the effectiveness of a prototype buffer bulbous bow......) and the forward velocity of the struck ship on the collapse mode of the bow of the striking vessel are investigated. Collapse modes, contact forces and energy absorption capabilities of the buffer bows are compared with those of conventional bows....

  2. Energy and competition: research on the juridical mutations induced by the opening of the electric power and gas sectors

    International Nuclear Information System (INIS)

    Lemaire, Ch.

    2003-01-01

    This document deals with juridical and economical consequences of common directives from 1996 to 1998 in the french internal market of the electric power and gas. These consequences concern the market organization and its operating with a special interest to the operators and operations mutation. (A.L.B.)

  3. Present status of rarefied gas dynamics approach to the structure of a laser-induced evaporating jet

    International Nuclear Information System (INIS)

    Cercignani, C.

    1980-01-01

    With reference to the relation between the state of the surface and the measurements downstream in the dynamic laser pulse technique, the problems arising in connection with the study of the structure of a jet evaporating into a vacuum are investigated. Particular attention is paid to the following aspects gas surface interaction, internal degrees of freedom, presence of more than one species, chemical reactions

  4. Biomass-Ash-Induced Agglomeration in a Fluidized Bed. Part 1: Experimental Study on the Effects of a Gas Atmosphere

    DEFF Research Database (Denmark)

    Ma, Teng; Fan, Chuigang; Hao, Lifang

    2016-01-01

    . The agglomerates are analyzed by scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM–EDS) for morphology and elemental composition. Significant differences are observed on the defluidization temperature (Td) and agglomeration mechanisms in different gas atmospheres. Td in H2 and steam...

  5. Resolution doubling in 3D-STORM imaging through improved buffers.

    Science.gov (United States)

    Olivier, Nicolas; Keller, Debora; Gönczy, Pierre; Manley, Suliana

    2013-01-01

    Super-resolution imaging methods have revolutionized fluorescence microscopy by revealing the nanoscale organization of labeled proteins. In particular, single-molecule methods such as Stochastic Optical Reconstruction Microscopy (STORM) provide resolutions down to a few tens of nanometers by exploiting the cycling of dyes between fluorescent and non-fluorescent states to obtain a sparse population of emitters and precisely localizing them individually. This cycling of dyes is commonly induced by adding different chemicals, which are combined to create a STORM buffer. Despite their importance, the composition of these buffers has scarcely evolved since they were first introduced, fundamentally limiting what can be resolved with STORM. By identifying a new chemical suitable for STORM and optimizing the buffer composition for Alexa-647, we significantly increased the number of photons emitted per cycle by each dye, providing a simple means to enhance the resolution of STORM independently of the optical setup used. Using this buffer to perform 3D-STORM on biological samples, we obtained images with better than 10 nanometer lateral and 30 nanometer axial resolution.

  6. Resolution doubling in 3D-STORM imaging through improved buffers.

    Directory of Open Access Journals (Sweden)

    Nicolas Olivier

    Full Text Available Super-resolution imaging methods have revolutionized fluorescence microscopy by revealing the nanoscale organization of labeled proteins. In particular, single-molecule methods such as Stochastic Optical Reconstruction Microscopy (STORM provide resolutions down to a few tens of nanometers by exploiting the cycling of dyes between fluorescent and non-fluorescent states to obtain a sparse population of emitters and precisely localizing them individually. This cycling of dyes is commonly induced by adding different chemicals, which are combined to create a STORM buffer. Despite their importance, the composition of these buffers has scarcely evolved since they were first introduced, fundamentally limiting what can be resolved with STORM. By identifying a new chemical suitable for STORM and optimizing the buffer composition for Alexa-647, we significantly increased the number of photons emitted per cycle by each dye, providing a simple means to enhance the resolution of STORM independently of the optical setup used. Using this buffer to perform 3D-STORM on biological samples, we obtained images with better than 10 nanometer lateral and 30 nanometer axial resolution.

  7. Temperature buffer test. Installation of buffer, heaters and instruments in the deposition hole

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Lars-Erik; Sanden, Torbjoern; Aakesson, Mattias [Clay Technology AB, Lund (Sweden); Barcena, Ignacio; Garcia-Sineriz, Jose Luis [Aitemin, Madrid (Spain)

    2010-12-15

    During 2003 the Temperature Buffer Test was installed in Aespoe Hard Rock Laboratory. Temperature, water pressure, relative humidity, total pressure and displacements etc. are measured in numerous points in the test. Most of the cables from the transducers are led in the deposition hole through slots in the rock surface of the deposition hole in watertight tubes to the data collection system in a container placed in the tunnel close to the deposition hole. This report describes the work with the installations of the buffer, heaters, and instruments and yields a description of the final location of all instruments. The report also contains a description of the materials that were installed and the densities yielded after placement.

  8. Temperature buffer test. Installation of buffer, heaters and instruments in the deposition hole

    International Nuclear Information System (INIS)

    Johannesson, Lars-Erik; Sanden, Torbjoern; Aakesson, Mattias; Barcena, Ignacio; Garcia-Sineriz, Jose Luis

    2010-12-01

    During 2003 the Temperature Buffer Test was installed in Aespoe Hard Rock Laboratory. Temperature, water pressure, relative humidity, total pressure and displacements etc. are measured in numerous points in the test. Most of the cables from the transducers are led in the deposition hole through slots in the rock surface of the deposition hole in watertight tubes to the data collection system in a container placed in the tunnel close to the deposition hole. This report describes the work with the installations of the buffer, heaters, and instruments and yields a description of the final location of all instruments. The report also contains a description of the materials that were installed and the densities yielded after placement

  9. Comparison of Airway Responses Induced in a Mouse Model by the Gas and Particulate Fractions of Gasoline Direct Injection Engine Exhaust.

    Science.gov (United States)

    Maikawa, Caitlin L; Zimmerman, Naomi; Ramos, Manuel; Shah, Mittal; Wallace, James S; Pollitt, Krystal J Godri

    2018-03-01

    Diesel exhaust has been associated with asthma, but its response to other engine emissions is not clear. The increasing prevalence of vehicles with gasoline direct injection (GDI) engines motivated this study, and the objective was to evaluate pulmonary responses induced by acute exposure to GDI engine exhaust in an allergic asthma murine model. Mice were sensitized with an allergen to induce airway hyperresponsiveness or treated with saline (non-allergic group). Animals were challenged for 2-h to exhaust from a laboratory GDI engine operated at conditions equivalent to a highway cruise. Exhaust was filtered to assess responses induced by the particulate and gas fractions. Short-term exposure to particulate matter from GDI engine exhaust induced upregulation of genes related to polycyclic aromatic hydrocarbon (PAH) metabolism ( Cyp1b1 ) and inflammation ( TNFα ) in the lungs of non-allergic mice. High molecular weight PAHs dominated the particulate fraction of the exhaust, and this response was therefore likely attributable to the presence of these PAHs. The particle fraction of GDI engine exhaust further contributed to enhanced methacholine responsiveness in the central and peripheral tissues in animals with airway hyperresponsiveness. As GDI engines gain prevalence in the vehicle fleet, understanding the health impacts of their emissions becomes increasingly important.

  10. Comparison of Airway Responses Induced in a Mouse Model by the Gas and Particulate Fractions of Gasoline Direct Injection Engine Exhaust

    Directory of Open Access Journals (Sweden)

    Caitlin L. Maikawa

    2018-03-01

    Full Text Available Diesel exhaust has been associated with asthma, but its response to other engine emissions is not clear. The increasing prevalence of vehicles with gasoline direct injection (GDI engines motivated this study, and the objective was to evaluate pulmonary responses induced by acute exposure to GDI engine exhaust in an allergic asthma murine model. Mice were sensitized with an allergen to induce airway hyperresponsiveness or treated with saline (non-allergic group. Animals were challenged for 2-h to exhaust from a laboratory GDI engine operated at conditions equivalent to a highway cruise. Exhaust was filtered to assess responses induced by the particulate and gas fractions. Short-term exposure to particulate matter from GDI engine exhaust induced upregulation of genes related to polycyclic aromatic hydrocarbon (PAH metabolism (Cyp1b1 and inflammation (TNFα in the lungs of non-allergic mice. High molecular weight PAHs dominated the particulate fraction of the exhaust, and this response was therefore likely attributable to the presence of these PAHs. The particle fraction of GDI engine exhaust further contributed to enhanced methacholine responsiveness in the central and peripheral tissues in animals with airway hyperresponsiveness. As GDI engines gain prevalence in the vehicle fleet, understanding the health impacts of their emissions becomes increasingly important.

  11. Precursor Ion Scan Mode-Based Strategy for Fast Screening of Polyether Ionophores by Copper-Induced Gas-Phase Radical Fragmentation Reactions.

    Science.gov (United States)

    Crevelin, Eduardo J; Possato, Bruna; Lopes, João L C; Lopes, Norberto P; Crotti, Antônio E M

    2017-04-04

    The potential of copper(II) to induce gas-phase fragmentation reactions in macrotetrolides, a class of polyether ionophores produced by Streptomyces species, was investigated by accurate-mass electrospray tandem mass spectrometry (ESI-MS/MS). Copper(II)/copper(I) transition directly induced production of diagnostic acylium ions with m/z 199, 185, 181, and 167 from α-cleavages of [macrotetrolides + Cu] 2+ . A UPLC-ESI-MS/MS methodology based on the precursor ion scan of these acylium ions was developed and successfully used to identify isodinactin (1), trinactin (2), and tetranactin (3) in a crude extract of Streptomyces sp. AMC 23 in the precursor ion scan mode. In addition, copper(II) was also used to induce radical fragmentation reactions in the carboxylic acid polyether ionophore nigericin. The resulting product ions with m/z 755 and 585 helped to identify nigericin in a crude extract of Streptomyces sp. Eucal-26 by means of precursor ion scan experiments, demonstrating that copper-induced fragmentation reactions can potentially identify different classes of polyether ionophores rapidly and selectively.

  12. Axial- and radial-resolved electron density and excitation temperature of aluminum plasma induced by nanosecond laser: Effect of the ambient gas composition and pressure

    Directory of Open Access Journals (Sweden)

    Mahmoud S. Dawood

    2015-11-01

    Full Text Available The spatial variation of the characteristics of an aluminum plasma induced by a pulsed nanosecond XeCl laser is studied in this paper. The electron density and the excitation temperature are deduced from time- and space- resolved Stark broadening of an ion line and from a Boltzmann diagram, respectively. The influence of the gas pressure (from vacuum up to atmospheric pressure and compositions (argon, nitrogen and helium on these characteristics is investigated. It is observed that the highest electron density occurs near the laser spot and decreases by moving away both from the target surface and from the plume center to its edge. The electron density increases with the gas pressure, the highest values being occurred at atmospheric pressure when the ambient gas has the highest mass, i.e. in argon. The excitation temperature is determined from the Boltzmann plot of line intensities of iron impurities present in the aluminum target. The highest temperature is observed close to the laser spot location for argon at atmospheric pressure. It decreases by moving away from the target surface in the axial direction. However, no significant variation of temperature occurs along the radial direction. The differences observed between the axial and radial direction are mainly due to the different plasma kinetics in both directions.

  13. Predicting the safety and efficacy of buffer therapy to raise tumour pHe: an integrative modelling study

    Science.gov (United States)

    Martin, N K; Robey, I F; Gaffney, E A; Gillies, R J; Gatenby, R A; Maini, P K

    2012-01-01

    Background: Clinical positron emission tomography imaging has demonstrated the vast majority of human cancers exhibit significantly increased glucose metabolism when compared with adjacent normal tissue, resulting in an acidic tumour microenvironment. Recent studies demonstrated reducing this acidity through systemic buffers significantly inhibits development and growth of metastases in mouse xenografts. Methods: We apply and extend a previously developed mathematical model of blood and tumour buffering to examine the impact of oral administration of bicarbonate buffer in mice, and the potential impact in humans. We recapitulate the experimentally observed tumour pHe effect of buffer therapy, testing a model prediction in vivo in mice. We parameterise the model to humans to determine the translational safety and efficacy, and predict patient subgroups who could have enhanced treatment response, and the most promising combination or alternative buffer therapies. Results: The model predicts a previously unseen potentially dangerous elevation in blood pHe resulting from bicarbonate therapy in mice, which is confirmed by our in vivo experiments. Simulations predict limited efficacy of bicarbonate, especially in humans with more aggressive cancers. We predict buffer therapy would be most effectual: in elderly patients or individuals with renal impairments; in combination with proton production inhibitors (such as dichloroacetate), renal glomular filtration rate inhibitors (such as non-steroidal anti-inflammatory drugs and angiotensin-converting enzyme inhibitors), or with an alternative buffer reagent possessing an optimal pK of 7.1–7.2. Conclusion: Our mathematical model confirms bicarbonate acts as an effective agent to raise tumour pHe, but potentially induces metabolic alkalosis at the high doses necessary for tumour pHe normalisation. We predict use in elderly patients or in combination with proton production inhibitors or buffers with a pK of 7.1–7.2 is most

  14. Predicting the safety and efficacy of buffer therapy to raise tumour pHe: an integrative modelling study.

    Science.gov (United States)

    Martin, N K; Robey, I F; Gaffney, E A; Gillies, R J; Gatenby, R A; Maini, P K

    2012-03-27

    Clinical positron emission tomography imaging has demonstrated the vast majority of human cancers exhibit significantly increased glucose metabolism when compared with adjacent normal tissue, resulting in an acidic tumour microenvironment. Recent studies demonstrated reducing this acidity through systemic buffers significantly inhibits development and growth of metastases in mouse xenografts. We apply and extend a previously developed mathematical model of blood and tumour buffering to examine the impact of oral administration of bicarbonate buffer in mice, and the potential impact in humans. We recapitulate the experimentally observed tumour pHe effect of buffer therapy, testing a model prediction in vivo in mice. We parameterise the model to humans to determine the translational safety and efficacy, and predict patient subgroups who could have enhanced treatment response, and the most promising combination or alternative buffer therapies. The model predicts a previously unseen potentially dangerous elevation in blood pHe resulting from bicarbonate therapy in mice, which is confirmed by our in vivo experiments. Simulations predict limited efficacy of bicarbonate, especially in humans with more aggressive cancers. We predict buffer therapy would be most effectual: in elderly patients or individuals with renal impairments; in combination with proton production inhibitors (such as dichloroacetate), renal glomular filtration rate inhibitors (such as non-steroidal anti-inflammatory drugs and angiotensin-converting enzyme inhibitors), or with an alternative buffer reagent possessing an optimal pK of 7.1-7.2. Our mathematical model confirms bicarbonate acts as an effective agent to raise tumour pHe, but potentially induces metabolic alkalosis at the high doses necessary for tumour pHe normalisation. We predict use in elderly patients or in combination with proton production inhibitors or buffers with a pK of 7.1-7.2 is most promising.

  15. The buffer/container experiment: results, synthesis, issues

    International Nuclear Information System (INIS)

    Graham, J.; Chandler, N.A.; Dixon, D.A.; Roach, P.J.; To, T.; Wan, A.W.L.

    1997-12-01

    A large in-ground experiment has examined how heat affects the performance of the dense sand bentonite 'buffer' that has been proposed for use in the Canadian Nuclear Fuel Waste Management Program. The experiment was performed by Atomic Energy of Canada Limited at its Underground Research Laboratory, Lac du Bonnet, Manitoba between 1991 and 1994. The experiment placed a full-size heater representing a container of nuclear fuel waste in a 1.24-m diameter borehole filled with buffer below the floor of a room excavated at 240-m depth in granitic rock of the Canadian Shield. The buffer and surrounding rock were extensively instrumented for temperatures, total pressures, water pressures, suctions, and rock displacements. Power was provided to the heater for almost 900 days. The experiment showed that good rock conditions can be pre-selected, a borehole can be drilled, and buffer can be placed at controlled densities and water contents. The instrumentation generally worked well, and an extensive data base was successfully organized. Drying was observed in buffer close to the heater. This caused some desiccation cracking. However the cracks only extended approximately one third of the distance to the buffer-rock interface and did not form an advective pathway. Following sampling at the time of decommissioning, cracked samples of buffer were transported to the laboratory and given access to water. The hydraulic conductivities and swelling pressures of these resaturated samples were very similar to those of uncracked buffer. A good balance was achieved between the mass of water flowing into the experiment from the surrounding rock and the increased mass of water in the buffer. A good understanding was developed of the relationships between suctions, water contents, and total pressures in buffer near the buffer-rock interface. Comparisons between measurements and predictions of measured parameters show that a good understanding has been developed of the processes operating

  16. The buffer/container experiment: results, synthesis, issues

    Energy Technology Data Exchange (ETDEWEB)

    Graham, J. [Univ. of Manitoba, Dept. of Civil Engineering, Winnipeg, MB (Canada); Chandler, N.A.; Dixon, D.A.; Roach, P.J.; To, T.; Wan, A.W.L

    1997-12-01

    A large in-ground experiment has examined how heat affects the performance of the dense sand bentonite 'buffer' that has been proposed for use in the Canadian Nuclear Fuel Waste Management Program. The experiment was performed by Atomic Energy of Canada Limited at its Underground Research Laboratory, Lac du Bonnet, Manitoba between 1991 and 1994. The experiment placed a full-size heater representing a container of nuclear fuel waste in a 1.24-m diameter borehole filled with buffer below the floor of a room excavated at 240-m depth in granitic rock of the Canadian Shield. The buffer and surrounding rock were extensively instrumented for temperatures, total pressures, water pressures, suctions, and rock displacements. Power was provided to the heater for almost 900 days. The experiment showed that good rock conditions can be pre-selected, a borehole can be drilled, and buffer can be placed at controlled densities and water contents. The instrumentation generally worked well, and an extensive data base was successfully organized. Drying was observed in buffer close to the heater. This caused some desiccation cracking. However the cracks only extended approximately one third of the distance to the buffer-rock interface and did not form an advective pathway. Following sampling at the time of decommissioning, cracked samples of buffer were transported to the laboratory and given access to water. The hydraulic conductivities and swelling pressures of these resaturated samples were very similar to those of uncracked buffer. A good balance was achieved between the mass of water flowing into the experiment from the surrounding rock and the increased mass of water in the buffer. A good understanding was developed of the relationships between suctions, water contents, and total pressures in buffer near the buffer-rock interface. Comparisons between measurements and predictions of measured parameters show that a good understanding has been developed of the processes

  17. Communicating Low-Probability High-Consequence Risk, Uncertainty and Expert Confidence: Induced Seismicity of Deep Geothermal Energy and Shale Gas.

    Science.gov (United States)

    Knoblauch, Theresa A K; Stauffacher, Michael; Trutnevyte, Evelina

    2018-04-01

    Subsurface energy activities entail the risk of induced seismicity including low-probability high-consequence (LPHC) events. For designing respective risk communication, the scientific literature lacks empirical evidence of how the public reacts to different written risk communication formats about such LPHC events and to related uncertainty or expert confidence. This study presents findings from an online experiment (N = 590) that empirically tested the public's responses to risk communication about induced seismicity and to different technology frames, namely deep geothermal energy (DGE) and shale gas (between-subject design). Three incrementally different formats of written risk communication were tested: (i) qualitative, (ii) qualitative and quantitative, and (iii) qualitative and quantitative with risk comparison. Respondents found the latter two the easiest to understand, the most exact, and liked them the most. Adding uncertainty and expert confidence statements made the risk communication less clear, less easy to understand and increased concern. Above all, the technology for which risks are communicated and its acceptance mattered strongly: respondents in the shale gas condition found the identical risk communication less trustworthy and more concerning than in the DGE conditions. They also liked the risk communication overall less. For practitioners in DGE or shale gas projects, the study shows that the public would appreciate efforts in describing LPHC risks with numbers and optionally risk comparisons. However, there seems to be a trade-off between aiming for transparency by disclosing uncertainty and limited expert confidence, and thereby decreasing clarity and increasing concern in the view of the public. © 2017 Society for Risk Analysis.

  18. Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas

    International Nuclear Information System (INIS)

    Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin; Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping

    2012-01-01

    Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

  19. Risks Associated with Unconventional Gas Extraction Projects. Induced Seismicity, NORM and Ecological Risks; Riesgos Asociados a los Proyectos de Extracción de Gas no Convencional. Sismicidad Inducida, NORM y Riesgos Ecológicos

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo-Naharro, J.; Hurtado, A.; Eguilior, S.; Recreo, F.

    2015-07-01

    The latest technological advances in hydraulic fracturing (fracking) and horizontal drilling are globally driving the commercial extraction of unconventional resources. Although there is still no commercial exploitation of these resources within the EU, the fact that there are potential reserves in some countries, such as Spain, stimulates the need of performing preliminary studies to define the characteristics that an unconventional gas extraction project should consider. The object of these features are the safety of the project, thus minimizing the probabilities of negative environmental impacts, and especially since there is not any EU Framework Directive focusing on the regulation of the operation of such fossil fuels. A project of this nature, involving natural systems, must start from the knowledge of these systems and from an assessment of its features in order to reach the environmental safety of the operations. Moreover, the implementation of risk management systems, along with the existence of an appropriate legislation and supervision are key elements in the development of unconventional gas extraction projects that are environmentally friendly. The present report includes, among the overall risks associated with such projects, those related to: i) the induced seismicity; ii) the Naturally-Occurring Radioactive Materials (NORM); and iii) the ecology.

  20. Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

    Science.gov (United States)

    Kaya, Ismet I.; Eberl, Karl

    2007-05-01

    A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two-dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal can be interpreted as the analog of Bernoulli’s effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

  1. Analysis of Knock Phenomenon Induced in a Constant Volume Chamber by Local Gas Temperature Measurement and Visualization

    Science.gov (United States)

    Moriyoshi, Yasuo; Kobayashi, Shigemi; Enomoto, Yoshiteru

    Knock phenomenon in SI engines is regarded as an auto-ignition of unburned end-gas, and it has been widely examined by using rapid compression machines (RCM), shock-tubes or test engines. Recent researches point out the importance of the low temperature chemical reaction and the negative temperature coefficient (NTC). To investigate the effects, analyses of instantaneous local gas temperature, flow visualization and gaseous pressure were conducted in this study. As measurements using real engines are too difficult to analyze, the authors aimed to make measurements using a constant volume vessel under knock conditions where propagating flame exists during the induction time of auto-ignition. Adopting the two-wire thermocouple method enabled us to measure the instantaneous local gas temperature until the moment when the flame front passes by. High-speed images inside the unburned region were also recorded simultaneously using an endoscope. As a result, it was found that when knock occurs, the auto-ignition initiation time seems slightly early compared to the results without knock. This causes a higher volume ratio of unburned mixture and existence of many hot spots and stochastically leads to an initiation of knock.

  2. 2D and 3D imaging of the gas phase close to an operating model catalyst by planar laser induced fluorescence

    International Nuclear Information System (INIS)

    Blomberg, Sara; Gustafson, Johan; Lundgren, Edvin; Zhou, Jianfeng; Zetterberg, Johan

    2016-01-01

    In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS). These studies have provided an increased understanding of the surface dynamics and the structure of the active phase of surfaces and nano particles as a reaction occurs, providing novel information on the structure/activity relationship. However, the surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface. Therefore, the catalytic activity of the sample itself will act as a gas-source or gas-sink, and will affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, we have applied planar laser induced fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts. Our measurements demonstrate that the gas composition differs significantly close to the catalyst and at the position of the MS, which indeed should have a profound effect on the surface structure. However, PLIF applied to catalytic reactions presents several beneficial properties in addition to investigate the effect of the catalyst on the effective gas composition close to the model catalyst. The high spatial and temporal resolution of PLIF provides a unique tool to visualize the on-set of catalytic reactions and to compare different model catalysts in the same reactive environment. The technique can be

  3. 2D and 3D imaging of the gas phase close to an operating model catalyst by planar laser induced fluorescence

    Science.gov (United States)

    Blomberg, Sara; Zhou, Jianfeng; Gustafson, Johan; Zetterberg, Johan; Lundgren, Edvin

    2016-11-01

    In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS). These studies have provided an increased understanding of the surface dynamics and the structure of the active phase of surfaces and nano particles as a reaction occurs, providing novel information on the structure/activity relationship. However, the surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface. Therefore, the catalytic activity of the sample itself will act as a gas-source or gas-sink, and will affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, we have applied planar laser induced fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts. Our measurements demonstrate that the gas composition differs significantly close to the catalyst and at the position of the MS, which indeed should have a profound effect on the surface structure. However, PLIF applied to catalytic reactions presents several beneficial properties in addition to investigate the effect of the catalyst on the effective gas composition close to the model catalyst. The high spatial and temporal resolution of PLIF provides a unique tool to visualize the on-set of catalytic reactions and to compare different model catalysts in the same reactive environment. The technique can be

  4. Nanosolvation by acetonitrile and 18-crown-6 ether induce strongly different effects on the electron-capture induced dissociation of aromatic tripeptide cations in the gas phase

    DEFF Research Database (Denmark)

    MacLot, S.; Rangama, J.; Nielsen, Steen Brøndsted

    2013-01-01

    for acetonitrile. One or two acetonitrile molecules have also been found to induce little effect on the fragmentation patterns of the charge-reduced peptide ions. By contrast, one or two CE decreases the NH3-loss probability, which is accounted for by the inhibition of this channel upon CE binding to the N...

  5. Riparian ecosystems and buffers - multiscale structure, function, and management: introduction

    Science.gov (United States)

    Kathleen A. Dwire; Richard R. Lowrance

    2006-01-01

    Given the importance of issues related to improved understanding and management of riparian ecosystems and buffers, the American Water Resources Association (AWRA) sponsored a Summer Specialty Conference in June 2004 at Olympic Valley, California, entitled 'Riparian Ecosystems and Buffers: Multiscale Structure, Function, and Management.' The primary objective...

  6. Social Buffering of Stress in Development: A Career Perspective

    Science.gov (United States)

    Gunnar, Megan R.

    2016-01-01

    This review provides a broad overview of my research group's work on social buffering in human development in the context of the field. Much of the focus is on social buffering of the hypothalamic-pituitary-adrenocortical (HPA) system, one of the two major arms of the mammalian stress system. This focus reflects the centrality of the HPA system in research on social buffering in the fields of developmental psychobiology and developmental science. However, buffering of the cardiovascular and autonomic nervous system is also discussed. The central developmental question in this area derives from attachment theory which argues that the infant's experience of stress and arousal regulation in the context of her early attachment relationships is not an immature form of social buffering experienced in adulthood, but rather the foundation out of which individual differences in the capacity to gain stress relief from social partners emerge. The emergence of social buffering in infancy, changes in social buffering throughout childhood and adolescence, the influence of early experience on later individual differences in social buffering, and critical gaps in our knowledge are described. PMID:28544861

  7. Dynamic Buffer Capacity in Acid-Base Systems.

    Science.gov (United States)

    Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

    The generalized concept of 'dynamic' buffer capacity β V is related to electrolytic systems of different complexity where acid-base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton-Robinson buffers, taken as examples.

  8. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals

    DEFF Research Database (Denmark)

    Rugbjerg, Peter; Genee, Hans Jasper; Jensen, Kristian

    2016-01-01

    transcription factor, while interacting DNA-binding domains mediate the transduction of signal and form an interacting molecular buffer. The molecular buffer system enables modular signal inversion through integration with repressor modules. Further, tuning of input sensitivity was achieved through perturbation...

  9. Reduction of buffering requirements: Another advantage of cooperative transmission

    KAUST Repository

    Bader, Ahmed

    2015-04-01

    Yet another advent of cooperative transmission is exposed in this letter. It is shown that cooperation lends itself to the reduction of buffer sizes of wireless sensor nodes. It is less likely to find the channel busy when cooperative transmission is employed in the network. Otherwise, in the lack of cooperation, the probability of build up of packet queues in transmission buffers increases.

  10. Dynamic Buffer Capacity in Acid?Base Systems

    OpenAIRE

    Micha?owska-Kaczmarczyk, Anna M.; Micha?owski, Tadeusz

    2015-01-01

    The generalized concept of ?dynamic? buffer capacity ? V is related to electrolytic systems of different complexity where acid?base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton?Robinson buffers, taken as examples.

  11. Sampling phase lock loop (PLL) with low power clock buffer

    NARCIS (Netherlands)

    Gao, X.; Bahai, A.; Bohsali, M.; Djabbari, A.; Klumperink, Eric A.M.; Nauta, Bram; Socci, G.

    2013-01-01

    A sampling phase locked loop (PLL) circuit includes a pull-up/down buffer configured to convert an oscillator reference clock into a square wave sampling control signal input to a sampling phase detector. The buffer circuit is configured to reduce power by controlling the switching of the pull-up

  12. Bus Implementation Using New Low Power PFSCL Tristate Buffers

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2016-01-01

    Full Text Available This paper proposes new positive feedback source coupled logic (PFSCL tristate buffers suited to bus applications. The proposed buffers use switch to attain high impedance state and modify the load or the current source section. An interesting consequence of this is overall reduction in the power consumption. The proposed tristate buffers consume half the power compared to the available switch based counterpart. The issues with available PFSCL tristate buffers based bus implementation are identified and benefits of employing the proposed tristate buffer topologies are put forward. SPICE simulation results using TSMC 180 nm CMOS technology parameters are included to support the theoretical formulations. The performance of proposed tristate buffer topologies is examined on the basis of propagation delay, output enable time, and power consumption. It is found that one of the proposed tristate buffer topology outperforms the others in terms of all the performance parameters. An examination of behavior of available and the proposed PFSCL tristate buffer topologies under parameter variations and mismatch shows a maximum variation of 14%.

  13. Effects of riparian buffers on hydrology of northern seasonal ponds

    Science.gov (United States)

    Randall K. Kolka; Brian J. Palik; Daniel P. Tersteeg; James C. Bell

    2011-01-01

    Although seasonal ponds are common in northern, glaciated, forested landscapes, forest management guidelines are generally lacking for these systems. The objective of this study was to determine the effect of riparian buffer type on seasonal pond hydrology following harvest of the adjacent upland forest. A replicated block design consisting of four buffer treatments...

  14. Behavior and nutritional condition buffer a large-bodied endotherm against direct and indirect effects of climate

    Science.gov (United States)

    Ryan A. Long; R. Terry Bowyer; Warren P. Porter; Paul Mathewson; Kevin L. Monteith; John G. Kie

    2014-01-01

    Temporal changes in net energy balance of animals strongly influence fitness; consequently, natural selection should favor behaviors that increase net energy balance by buffering individuals against negative effects of environmental variation. The relative importance of behavioral responses to climate-induced variation in costs vs. supplies of energy, however, is...

  15. Impact of solute concentration on the electrocatalytic conversion of dissolved gases in buffered solutions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-04-24

    To maintain local pH levels near the electrode during electrochemical reactions, the use of buffer solutions is effective. Nevertheless, the critical effects of the buffer concentration on electrocatalytic performances have not been discussed in detail. In this study, two fundamental electrochemical reactions, oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR), on a platinum rotating disk electrode are chosen as model gas-related aqueous electrochemical reactions at various phosphate concentrations. Our detailed investigations revealed that the kinetic and limiting diffusion current densities for both the ORR and HOR logarithmically decrease with increasing solute concentration (log|jORR|=-0.39c+0.92,log|jHOR|=-0.35c+0.73). To clarify the physical aspects of this phenomenon, the electrolyte characteristics are addressed: with increasing phosphate concentration, the gas solubility decrease, the kinematic viscosity of the solution increase and the diffusion coefficient of the dissolved gases decrease. The simulated limiting diffusion currents using the aforementioned parameters match the measured ones very well (log|jORR|=-0.43c+0.99,log|jHOR|=-0.40c+0.54), accurately describing the consequences of the electrolyte concentration. These alterations of the electrolyte properties associated with the solute concentration are universally applicable to other aqueous gas-related electrochemical reactions because the currents are purely determined by mass transfer of the dissolved gases. © 2015 The Authors.

  16. Smooth Nb surfaces fabricated by buffered electropolishing

    International Nuclear Information System (INIS)

    Wu, Andy T.; Mammosser, John; Phillips, Larry; Delayen, Jean; Reece, Charles; Wilkerson, Amy; Smith, David; Ike, Robert

    2007-01-01

    It was demonstrated that smooth Nb surfaces could be obtained through buffered electropolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process were optimized to achieve a smooth surface finish. The polishing rate of BEP was determined to be 0.646 μm/min which was much higher than 0.381 μm/min achieved by the conventional electropolishing (EP) process widely used in the superconducting radio frequency (SRF) community. Root mean square measurements using a 3D profilometer revealed that Nb surfaces treated by BEP were an order of magnitude smoother than those treated by the optimized EP process. The chemical composition of the Nb surfaces after BEP was analyzed by static and dynamic secondary ion mass spectrometry (SIMS) systems. SIMS results implied that the surface oxide structure of Nb might be more complicated than what usually believed and could be inhomogeneous. Preliminary results of BEP on Nb SRF single cell cavities and half-cells were reported. It was shown that smooth and bright surfaces could be obtained in 1800 s when the electric field inside a SRF cavity was uniform during a BEP process. This study showed that BEP is a promising technique for surface treatment on Nb SRF cavities to be used in particle accelerators

  17. Buffers for biomass production in temperate European agriculture

    DEFF Research Database (Denmark)

    Christen, Benjamin; Dalgaard, Tommy

    2013-01-01

    , environmental pressures from intensive agriculture and policy developments. Use of conservation buffers by farmers outside of designated schemes is limited to date, but the increasing demand for bioenergy and the combination of agricultural production with conservation calls for a much wider implementation....... This paper reviews the biophysical knowledge on buffer functioning and associated ecosystem services. It describes how a three-zone buffer design, with arable fields buffered in combination by grassland, short rotation forestry (SRF) or coppice (SRC) and undisturbed vegetation along water courses, can...... be incorporated into farming landscapes as productive conservation elements and reflects on the potential for successful implementation. Land use plays a much greater role in determining catchment hydrology than soil type: shelterbelts or buffer strips have markedly higher infiltration capacity than arable...

  18. Evaluation on elution feature of bentonite buffer materials

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Hirohisa; Kanno, Takeshi; Matsumoto, Kazuhiro

    1997-09-01

    In order to evaluate long term physical stability of artificial barrier in land disposal of high level radioactive wastes, it is necessary to know quantitatively elution behavior of buffering materials from disposal road (or cavity) to circumferential rock crack. When elution of the buffer material occurs on large scale, amount of bentonite in the disposal road (or cavity) reduces and reduction of various functions expected to the buffer materials is presumed. According to specification examples of road transverse arrangement and disposal vertical arrangement systems, evaluation on elution amount of the buffer materials at disposal environment was conducted. Opening width of rock crack in the disposal environment was supposed to be 0.5 mm. As a result, obtained mass elution ratios of the buffer materials due to extrusion phenomenon were 0.04 to 0.2% after 10,000 year and 2 to 12% after 1,000,000 years. (G.K.)

  19. Thin film photovoltaic devices with a minimally conductive buffer layer

    Science.gov (United States)

    Barnes, Teresa M.; Burst, James

    2016-11-15

    A thin film photovoltaic device (100) with a tunable, minimally conductive buffer (128) layer is provided. The photovoltaic device (100) may include a back contact (150), a transparent front contact stack (120), and an absorber (140) positioned between the front contact stack (120) and the back contact (150). The front contact stack (120) may include a low resistivity transparent conductive oxide (TCO) layer (124) and a buffer layer (128) that is proximate to the absorber layer (140). The photovoltaic device (100) may also include a window layer (130) between the buffer layer (128) and the absorber (140). In some cases, the buffer layer (128) is minimally conductive, with its resistivity being tunable, and the buffer layer (128) may be formed as an alloy from a host oxide and a high-permittivity oxide. The high-permittivity oxide may further be chosen to have a bandgap greater than the host oxide.

  20. Multi-Buffer Simulations for Trace Language Inclusion

    Directory of Open Access Journals (Sweden)

    Milka Hutagalung

    2016-09-01

    Full Text Available We consider simulation games played between Spoiler and Duplicator on two Büchi automata in which the choices made by Spoiler can be buffered by Duplicator in several buffers before she executes them on her structure. We show that the simulation games are useful to approximate the inclusion of trace closures of languages accepted by finite-state automata, which is known to be undecidable. We study the decidability and complexity and show that the game with bounded buffers can be decided in polynomial time, whereas the game with one unbounded and one bounded buffer is highly undecidable. We also show some sufficient conditions on the automata for Duplicator to win the game (with unbounded buffers.