WorldWideScience

Sample records for high co2 pressure

  1. Silicate minerals for CO2 scavenging from biogas in Autogenerative High Pressure Digestion

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Ferrer, I.; Weijma, J.; Lier, van J.B.

    2013-01-01

    Autogenerative High Pressure Digestion (AHPD) is a novel concept that integrates gas upgrading with anaerobic digestion by selective dissolution of CO2 at elevated biogas pressure. However, accumulation of CO2 and fatty acids after anaerobic digestion of glucose resulted in pH 3–5, which is

  2. High Materials Performance in Supercritical CO2 in Comparison with Atmospheric Pressure CO2 and Supercritical Steam

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Tylczak, Joseph [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Carney, Casey [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Dogan, Omer N. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2017-02-26

    This presentation covers environments (including advanced ultra-supercritical (A-USC) steam boiler/turbine and sCO2 indirect power cycle), effects of pressure, exposure tests, oxidation results, and mechanical behavior after exposure.

  3. High pressure X-ray preionized TEMA-CO2 laser

    NARCIS (Netherlands)

    Bonnie, R.J.M.; Witteman, W.J.

    1987-01-01

    The construction of a high-pressure (up to 20 atm) transversely excited CO2 laser using transverse X-ray preionization is described. High pressure operation was found to be greatly improved in comparison to UV-preionized systems. Homogeneous discharges have been achieved in the pressure range 5–20

  4. Measurement and modeling of high-pressure (vapour + liquid) equilibria of (CO2 + alcohol) binary systems

    International Nuclear Information System (INIS)

    Gutierrez, Jorge E.; Bejarano, Arturo; Fuente, Juan C. de la

    2010-01-01

    An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at 2 + 1-propanol), (CO 2 + 2-methyl-1-propanol), (CO 2 + 3-methyl-1-butanol), and (CO 2 + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO 2 + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively.

  5. High pressure X-ray preionized TEMA-CO2 laser

    Science.gov (United States)

    Bonnie, R. J. M.; Witteman, W. J.

    1987-09-01

    The construction of a high-pressure (up to 20 atm) transversely excited CO2 laser using transverse X-ray preionization is described. High pressure operation was found to be greatly improved in comparison to UV-preionized systems. Homogeneous discharges have been achieved in the pressure range 5-20 atm, yielding a specific laser output in the order of 35 J/l.

  6. Phase equilibrium data and thermodynamic modeling of the system (CO2 + biodiesel + methanol) at high pressures

    International Nuclear Information System (INIS)

    Pinto, Leandro F.; Segalen da Silva, Diogo Italo; Rosa da Silva, Fabiano; Ramos, Luiz P.; Ndiaye, Papa M.; Corazza, Marcos L.

    2012-01-01

    Highlights: → We measured phase behavior for the system involving {CO 2 + biodiesel + methanol}. → The saturation pressures were obtained using a variable-volume view cell. → The experimental data were modeled using PR-vdW2 and PR-WS equations of state. - Abstract: The main objective of this work was to investigate the high pressure phase behavior of the binary systems {CO 2 (1) + methanol(2)} and {CO 2 (1) + soybean methyl esters (biodiesel)(2)} and the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} were determined. Biodiesel was produced from soybean oil, purified, characterized and used in this work. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (303.15 to 343.15) K and pressures up to 21 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.2383 to 0.8666) for the binary system {CO 2 (1) + methanol(2)}; (0.4201 to 0.9931) for the binary system {CO 2 (1) + biodiesel(2)}; (0.4864 to 0.9767) for the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} with a biodiesel to methanol molar ratio of (1:3); and (0.3732 to 0.9630) for the system {CO 2 + biodiesel + methanol} with a biodiesel to methanol molar ratio of (8:1). For these systems, (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng-Robinson equation of state with the classical van der Waals (PR-vdW2) and Wong-Sandler (PR-WS) mixing rules. Both thermodynamic models were able to satisfactorily correlate the phase behavior of the systems investigated and the PR-WS presented the best performance.

  7. Design of experimental setup for supercritical CO2 jet under high ambient pressure conditions

    Science.gov (United States)

    Shi, Huaizhong; Li, Gensheng; He, Zhenguo; Wang, Haizhu; Zhang, Shikun

    2016-12-01

    With the commercial extraction of hydrocarbons in shale and tight reservoirs, efficient methods are needed to accelerate developing process. Supercritical CO2 (SC-CO2) jet has been considered as a potential way due to its unique fluid properties. In this article, a new setup is designed for laboratory experiment to research the SC-CO2 jet's characteristics in different jet temperatures, pressures, standoff distances, ambient pressures, etc. The setup is composed of five modules, including SC-CO2 generation system, pure SC-CO2 jet system, abrasive SC-CO2 jet system, CO2 recovery system, and data acquisition system. Now, a series of rock perforating (or case cutting) experiments have been successfully conducted using the setup about pure and abrasive SC-CO2 jet, and the results have proven the great perforating efficiency of SC-CO2 jet and the applications of this setup.

  8. Interfacial tension measurement between CO2 and brines under high temperature and elevated pressure conditions

    Science.gov (United States)

    Li, X.; Boek, E. S.; Maitland, G. C.; Trusler, J. P. M.

    2012-04-01

    We have investigated the dependence of interfacial tension of (CO2 + brine) on temperature, pressure and salinity (including both salt type and molality) over the range of conditions applicable to CO2 storage in saline aquifers. The study covered a wide range of measurements of the interfacial tensions between carbon dioxide and (NaCl + KCl)(aq), CaCl2(aq), MgCl2(aq), Na2SO4(aq), KHCO3(aq), NaHCO3(aq) and two laboratory constructed brines with molality ranging from (0.3 to 5.0) mol·kg-1. The measurements were made at temperatures between (298 and 448) K at various pressures up to 50 MPa, using the pendant drop method in a high-pressure view cell filled with water-saturated CO2. The drop to be imaged was created by injecting brine from a high-pressure syringe pump into a capillary sealed through the top of the cell. The expanded uncertainties of the experimental state variables at 95 % confidence are +0.05 K in temperature and +70 kPa in pressure. For the interfacial tension, the overall expanded relative uncertainty at 95 % confidence was +1.6%. The experimental results show that interfacial tension for all the systems increases linearly with molality, indicating that relatively few measurements and simple interpolation procedures are adequate for describing this property accurately over wide ranges of conditions.

  9. Exploring the Phase Diagram SiO2-CO2 at High Pressures and Temperatures

    Science.gov (United States)

    Kavner, A.

    2015-12-01

    CO2 is an important volatile system relevant for planetary sciences and fundamental chemistry. Molecular CO2 has doubly bonded O=C=O units but high pressure-high temperature (HP-HT) studies have recently shown its transformation into a three-dimensional network of corner-linked [CO4] units analogous to the silica mineral polymorphs, through intermediate non-molecular phases. Here, we report P-V-T data on CO2-IV ice from time-of-flight neutron diffraction experiments, which allow determining the compressibility and thermal expansivity of this intermediate molecular-to-non-molecular phase.1 Aditionally, we have explored the SiO2-CO2 phase diagram and the potential formation of silicon carbonate compounds. New data obtained by laser-heating diamond-anvil experiments in CO2-filled microporous silica polymorphs will be shown. In particular, these HP-HT experiments explore the existence of potential CO2/SiO2 compounds with tetrahedrally-coordinated C/Si atoms by oxygens, which are predicted to be stable (or metastable) by state-of-the-art ab initio simulations.2,3 These theoretical predictions were supported by a recent study that reports the formation of a cristobalite-type Si0.4C0.6O2 solid solution at high-pressures and temperatures, which can be retained as a metastable solid down to ambient conditions.4 Entirely new families of structures could exist based on [CO4]4- units in various degrees of polymerisation, giving rise to a range of chain, sheet and framework solids like those found in silicate chemistry. References[1] S. Palaich et al., Am. Mineral. Submitted (2015) [2] A. Morales-Garcia et al., Theor. Chem. Acc. 132, 1308 (2013) [3] R. Zhou et al., Phys. Rev. X, 4, 011030 (2014) [4] M. Santoro et al. Nature Commun. 5, 3761 (2014)

  10. High-frequency pressure variations in the vicinity of a surface CO2 flux chamber

    Science.gov (United States)

    Eugene S. Takle; James R. Brandle; R. A. Schmidt; Rick Garcia; Irina V. Litvina; William J. Massman; Xinhua Zhou; Geoffrey Doyle; Charles W. Rice

    2003-01-01

    We report measurements of 2Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO2 flux chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface fluxes of CO2. Under the moderate wind speeds, warm temperatures,...

  11. Inactivation of Bacillus subtilis spores by high pressure CO2 with high temperature.

    Science.gov (United States)

    Rao, Lei; Xu, Zhenzhen; Wang, Yongtao; Zhao, Feng; Hu, Xiaosong; Liao, Xiaojun

    2015-07-16

    The objective of this study was to investigate the inactivation of the Bacillus subtilis spores by high pressure CO2 combined with high temperature (HPCD+HT) and to analyze the clumping effect of the spores on their HPCD+HT resistance. The spores of B. subtilis were subjected to heat at 0.1 MPa and HPCD at 6.5-25 MPa, and 82 °C, 86 °C, and 91 °C for 0-120 min. The spores were effectively inactivated by HPCD+HT, but a protective effect on the spores was also found, which was closely correlated to the pressure, temperature and time. The spores treated by HPCD+HT at 6.5 and 10 MPa exhibited a two-stage inactivation curve of shoulder and log-linear regions whereas the spores at 15-25 MPa exhibited a three-stage inactivation curve of shoulder, log-linear and tailing regions, and these curves were well fitted to the Geeraerd model. Approximately 90% of pyridine-2,6-dicarboxylic acid (DPA) was released after HPCD+HT and the 90% DPA release time depend on the pressure and temperature. Moreover, the spore clumping in suspensions was examined by dynamic light scattering. The particle size of the spore suspensions increased with the increase of pressure, temperature and time, indicating the spore clumping. 0.1% Tween 80 as a surfactant inhibited the spore clumping and increased the inactivation ratio of the spores by HPCD+HT. These results indicated that the spore clumping enhanced the spores' resistance to HPCD+HT and induced a protective effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. High Pressure Adsorption Isotherm of CO2 on Activated Carbon using Volumetric Method

    Directory of Open Access Journals (Sweden)

    Awaludin Martin

    2011-05-01

    Full Text Available Adsorption system is ones of the most effective methods for CO2 separating with other substances that produced from the burning of fossil fuels. In the design for that application, beside of characteristics of porous material (adsorbent data, CO2 adsorption data on the adsorbent (kinetic and thermodynamic are also needed. The aim of this research is resulting isothermal adsorption data at pressures up to 3.5 MPa by indirect methods (volumetric method at isothermal temperature of 300, 308, 318 and 338 K. Adsorbent that used in this research is activated carbon made from East of Kalimantan coals by physical activation method (CO2 which is the surface area of activated carbon is 668 m2/g and pore volume is 0.47 mL/g. Carbon dioxide (CO2 that used in this research is high purity carbon dioxide with a purity of 99.9%. Data from the experiment results then correlated using the Langmuir and Toth equations model. The results showed that the maximum adsorption capacity is 0.314 kg/kg at 300 K and 3384.69 kPa. The results of regression of experiment data using Langmuir and Toth models were 3.4% and 1.7%.

  13. High-pressure phase diagrams of liquid CO2 and N2

    Science.gov (United States)

    Boates, Brian; Bonev, Stanimir

    2011-06-01

    The phase diagrams of liquid CO2 and N2 have been investigated using first-principles theory. Both materials exhibit transitions to conducting liquids at high temperatures (T) and relatively modest pressures (P). Furthermore, both liquids undergo polymerization phase transitions at pressures comparable to their solid counterparts. The liquid phase diagrams have been divided into several regimes through a detailed analysis of changes in bonding, as well as structural and electronic properties for pressures and temperatures up to 200 GPa and 10 000 K, respectively. Similarities and differences between the high- P and T behavior of these fluids will be discussed. Calculations of the Hugoniot are in excellent agreement with available experimental data. Work supported by NSERC, LLNL, and the Killam Trusts. Prepared by LLNL under Contract DE-AC52-07NA27344.

  14. High-pressure vapor-liquid equilibrium data for CO2-orange peel oil

    Directory of Open Access Journals (Sweden)

    G.R. Stuart

    2000-06-01

    Full Text Available Recently, there has been a growing interest in fractionating orange peel oil by the use of supercritical carbon dioxide (SCCO2. However, progress in this area has been hindered by the lack of more comprehensive work concerning the phase equilibrium behavior of the SCCO2-orange peel oil system. In this context, the aim of this work is to provide new phase equilibrium data for this system over a wide range of temperatures and pressures, permitting the construction of coexistence PT-xy curves as well as the P-T diagram. The experiments were performed in a high-pressure variable-volume view cell in the temperature range of 50-70ºC from 70 to 135 atm and in the CO2 mass fraction composition range of 0.35-0.98. Based on the experimental phase equilibrium results, appropriate operating conditions can be set for high-pressure fractionation purposes.

  15. Highly efficient Cu-decorated iron oxide nanocatalyst for low pressure CO 2 conversion

    Energy Technology Data Exchange (ETDEWEB)

    Halder, Avik; Kilianová, Martina; Yang, Bing; Tyo, Eric C.; Seifert, Soenke; Prucek, Robert; Panáček, Aleš; Suchomel, Petr; Tomanec, Ondřej; Gosztola, David J.; Milde, David; Wang, Hsien-Hau; Kvítek, Libor; Zbořil, Radek; Vajda, Stefan

    2018-06-01

    We report a nanoparticulate iron oxide based catalyst for CO2 conversion with high efficiency at low pressures and on the effect of the presence of copper on the catalyst's restructuring and its catalytic performance. In situ X-ray scattering reveals the restructuring of the catalyst at the nanometer scale. In situ X-ray absorption near edge structure (XANES) shows the evolution of the composition and oxidation state of the iron and copper components under reaction conditions along with the promotional effect of copper on the chemical transformation of the iron component. X-ray diffraction (XRD), XANES and Raman spectroscopy proved that the starting nano catalyst is composed of iron oxides differing in chemical nature (alpha-Fe2O3, Fe3O4, FeO(OH)) and dimensionality, while the catalyst after CO2 conversion was identified as a mixture of alpha-Fe, Fe3C, and traces of Fe5C2. The significant increase of the rate CO2 is turned over in the presence of copper nanoparticles indicates that Cu nanoparticles activate hydrogen, which after spilling over to the neighbouring iron sites, facilitate a more efficient conversion of carbon dioxide.

  16. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement.

    Science.gov (United States)

    Ogieglo, Wojciech; Ghanem, Bader; Ma, Xiaohua; Wessling, Matthias; Pinnau, Ingo

    2018-04-04

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO 2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, n rel , it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in n rel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO 2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO 2 , the effective reduction of the T g was estimated to be ∼200 °C going from 128 to 7 nm films.

  17. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement

    KAUST Repository

    Ogieglo, Wojciech

    2018-03-12

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.

  18. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement

    KAUST Repository

    Ogieglo, Wojciech; Ghanem, Bader; Ma, Xiaohua; Wessling, Matthias; Pinnau, Ingo

    2018-01-01

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.

  19. Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO2 + alkanol) binary systems

    International Nuclear Information System (INIS)

    Bejarano, Arturo; Gutierrez, Jorge E.; Araus, Karina A.; Fuente, Juan C. de la

    2011-01-01

    Research highlights: → (Vapor + liquid) equilibria of three (CO 2 + C 5 alcohol) binary systems were measured. → Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. → No liquid immiscibility was observed at the temperatures and pressures studied. → Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. → Correlation results showed relative deviations ≤8 % (liquid) and ≤2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO 2 + 3-methyl-2-butanol), (CO 2 + 2-pentanol), and (CO 2 + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO 2 + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

  20. Viability and adaptation potential of indigenous microorganisms from natural gas field fluids in high pressure incubations with supercritical CO2.

    Science.gov (United States)

    Frerichs, Janin; Rakoczy, Jana; Ostertag-Henning, Christian; Krüger, Martin

    2014-01-21

    Carbon Capture and Storage (CCS) is currently under debate as large-scale solution to globally reduce emissions of the greenhouse gas CO2. Depleted gas or oil reservoirs and saline aquifers are considered as suitable reservoirs providing sufficient storage capacity. We investigated the influence of high CO2 concentrations on the indigenous bacterial population in the saline formation fluids of a natural gas field. Bacterial community changes were closely examined at elevated CO2 concentrations under near in situ pressures and temperatures. Conditions in the high pressure reactor systems simulated reservoir fluids i) close to the CO2 injection point, i.e. saturated with CO2, and ii) at the outer boundaries of the CO2 dissolution gradient. During the incubations with CO2, total cell numbers remained relatively stable, but no microbial sulfate reduction activity was detected. After CO2 release and subsequent transfer of the fluids, an actively sulfate-respiring community was re-established. The predominance of spore-forming Clostridiales provided evidence for the resilience of this taxon against the bactericidal effects of supercritical (sc)CO2. To ensure the long-term safety and injectivity, the viability of fermentative and sulfate-reducing bacteria has to be considered in the selection, design, and operation of CCS sites.

  1. High-Calorific Biogas Production by Selective CO2 Retention at Autogenerated Biogas Pressures up to 20 Bar

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Weijma, J.; Lier, van J.B.

    2012-01-01

    Autogenerative high pressure digestion (AHED) is a novel configuration of anaerobic digestion, in which micro-organisms produce autogenerated biogas pressures up to 90 bar with >90% CH4-content in a single step reactor. The less than 10% CO2-content was postulated to be resulting from

  2. Phase behavior for the poly(alkyl methacrylate)+supercritical CO2+DME mixture at high pressures

    International Nuclear Information System (INIS)

    Choi, Yong-Seok; Chio, Sang-Won; Byun, Hun-Soo

    2016-01-01

    The phase behavior curves of binary and ternary system were measured for poly(alkyl methacrylate) in supercritical CO 2 , as well as for the poly(alkyl methacrylate)+dimethyl ether (DME) (or 1-butene) in CO 2 . The solubility curves are reported for the poly(alkyl methacrylate)+DME in supercritical CO 2 at temperature from (300 to 465) K and a pressure from (3.66 to 248) MPa. Also, The high-pressure static-type apparatus of cloud-point curve was tested by comparing the measured phase behavior data of the poly(methyl methacrylate) [PMMA]+CO 2 +20.0 and 30.4 wt% methyl methacrylate (MMA) system with literature data of 10.4, 28.8 and 48.4 wt% MMA concentration. The phase behavior data for the poly(alkyl methacrylate)+CO 2 +DME mixture were measured in changes of the pressure-temperature (p, T) slope and with DME concentrations. Also, the cloud-point pressure for the poly(alkyl methacrylate)+1- butene solution containing supercritical CO 2 shows from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region at concentration range from (0.0 to 95) wt% 1-butene at below 455 K and at below 245MPa.

  3. Phase equilibrium measurements and thermodynamic modelling for the system (CO2 + ethyl palmitate + ethanol) at high pressures

    International Nuclear Information System (INIS)

    Gaschi, Priscilla S.; Mafra, Marcos R.; Ndiaye, Papa M.; Corazza, Marcos L.

    2013-01-01

    Graphical abstract: Ethyl palmitate and biodiesel comparison in a pressure–composition diagram for the systems (CO 2 + ethyl palmitate + biodiesel), at different temperatures. Highlights: ► We measured VLE, LLE, and VLLE for the system (CO 2 + ethyl palmitate + ethanol). ► The saturation pressures were obtained using a variable-volume view cell. ► Phase envelope of (CO 2 + ethyl palmitate) is different that (CO 2 + soybean oil biodiesel). ► The experimental data were modeled using PR-vdW2 and PR–WS equations of state. - Abstract: This work reports phase equilibrium measurements for the binary {CO 2 (1) + ethyl palmitate(2)} and ternary {CO 2 (1) + ethyl palmitate(2) + ethanol(3)} systems at high pressures. There is currently great interest in biodiesel production processes involving supercritical and/or pressurized solvents, such as non-catalytic supercritical biodiesel production and enzyme-catalysed biodiesel production. Also, supercritical CO 2 can offer an interesting alternative for glycerol separation in the biodiesel purification step in a water-free process. In this context, the main goal of this work was to investigate the phase behaviour of binary and ternary systems involving CO 2 , a pure constituent of biodiesel ethyl palmitate and ethanol. Experiments were carried out in a high-pressure variable-volume view cell with operating temperatures ranging from (303.15 to 353.15) K and pressures up to 21 MPa. The CO 2 mole fraction ranged from 0.5033 to 0.9913 for the binary {CO 2 (1) + ethyl palmitate(2)} system and from 0.4436 to 0.9712 for ternary system {CO 2 (1) + ethyl palmitate(2) + ethanol(3)} system with ethyl ester to ethanol molar ratios of (1:6), (1:3), and (1:1). For the systems investigated, vapour–liquid (VL), liquid–liquid (LL) and vapour–liquid–liquid (VLL) phase transitions were observed. The experimental data sets were successfully modeled using the Peng–Robinson equation of state with the classical van der Waals

  4. Impact of CO2 injection protocol on fluid-solid reactivity: high-pressure and temperature microfluidic experiments in limestone

    Science.gov (United States)

    Jimenez-Martinez, Joaquin; Porter, Mark; Carey, James; Guthrie, George; Viswanathan, Hari

    2017-04-01

    Geological sequestration of CO2 has been proposed in the last decades as a technology to reduce greenhouse gas emissions to the atmosphere and mitigate the global climate change. However, some questions such as the impact of the protocol of CO2 injection on the fluid-solid reactivity remain open. In our experiments, two different protocols of injection are compared at the same conditions (8.4 MPa and 45 C, and constant flow rate 0.06 ml/min): i) single phase injection, i.e., CO2-saturated brine; and ii) simultaneous injection of CO2-saturated brine and scCO2. For that purpose, we combine a unique high-pressure/temperature microfluidics experimental system, which allows reproducing geological reservoir conditions in geo-material substrates (i.e., limestone, Cisco Formation, Texas, US) and high resolution optical profilometry. Single and multiphase flow through etched fracture networks were optically recorded with a microscope, while processes of dissolution-precipitation in the etched channels were quantified by comparison of the initial and final topology of the limestone micromodels. Changes in hydraulic conductivity were quantified from pressure difference along the micromodel. The simultaneous injection of CO2-saturated brine and scCO2, reduced the brine-limestone contact area and also created a highly heterogeneous velocity field (i.e., low velocities regions or stagnation zones, and high velocity regions or preferential paths), reducing rock dissolution and enhancing calcite precipitation. The results illustrate the contrasting effects of single and multiphase flow on chemical reactivity and suggest that multiphase flow by isolating parts of the flow system can enhance CO2 mineralization.

  5. CO2-assisted high pressure homogenization: a solvent-free process for polymeric microspheres and drug-polymer composites.

    Science.gov (United States)

    Kluge, Johannes; Mazzotti, Marco

    2012-10-15

    The study explores the enabling role of near-critical CO(2) as a reversible plasticizer in the high pressure homogenization of polymer particles, aiming at their comminution as well as at the formation of drug-polymer composites. First, the effect of near-critical CO(2) on the homogenization of aqueous suspensions of poly lactic-co-glycolic acid (PLGA) was investigated. Applying a pressure drop of 900 bar and up to 150 passes across the homogenizer, it was found that particles processed in the presence of CO(2) were generally of microspherical morphology and at all times significantly smaller than those obtained in the absence of a plasticizer. The smallest particles, exhibiting a median x(50) of 1.3 μm, were obtained by adding a small quantity of ethyl acetate, which exerts on PLGA an additional plasticizing effect during the homogenization step. Further, the study concerns the possibility of forming drug-polymer composites through simultaneous high pressure homogenization of the two relevant solids, and particularly the effect of near-critical CO(2) on this process. Therefore, PLGA was homogenized together with crystalline S-ketoprofen (S-KET), a non-steroidal anti-inflammatory drug, at a drug to polymer ratio of 1:10, a pressure drop of 900 bar and up to 150 passes across the homogenizer. When the process was carried out in the presence of CO(2), an impregnation efficiency of 91% has been reached, corresponding to 8.3 wt.% of S-KET in PLGA; moreover, composite particles were of microspherical morphology and significantly smaller than those obtained in the absence of CO(2). The formation of drug-polymer composites through simultaneous homogenization of the two materials is thus greatly enhanced by the presence of CO(2), which increases the efficiency for both homogenization and impregnation. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. A synthetic-dynamic method for water solubility measurements in high pressure CO_2 using ATR–FTIR spectroscopy

    International Nuclear Information System (INIS)

    Comak, Gurbuz; Foltran, Stéphanie; Ke, Jie; Pérez, Eduardo; Sánchez-Vicente, Yolanda; George, Michael W.; Poliakoff, Martyn

    2016-01-01

    Highlights: • A synthetic method using ATR–FTIR spectroscopy has been developed to measure the solubility of water in CO_2_. • New data have been obtained for the dew point of the water at 4.05 MPa, 5.05 MPa and 6.03 MPa. • These data fill a gap in the literature and could be of significance for CO_2 transport in pipelines for CCS technology. - Abstract: A new synthetic method for studying phase behaviour is described using Attenuated Total Reflection (ATR) spectroscopy. The method has been developed to provide relevant information on the solubility of water in CO_2. The dew point of water has been determined at three different pressures, viz. (4.05, 5.05 and 6.03) MPa with mole fractions of water between 0.01 and 0.04. The data obtained fill the gap in the literature in these regions of pressures and temperatures and could be of high importance in the context of Carbon Capture and Storage (CCS) technology. Indeed, the presence of water in the captured CO_2 could damage the pipeline used for CO_2 transport. Hence, it is very important to have a fully understanding of the behaviour of the (CO_2 + H_2O) mixtures in wide range of temperature relevant for CCS.

  7. On the calculation of leakage rates from vessels filled with high density gaseous CO2 using pressure drop data

    International Nuclear Information System (INIS)

    George, A.F.

    1987-09-01

    This paper considers calculation methods to estimate leakage rates from pressure drop data from vessels filled with high pressure (40 bar) low temperature (25 0 C) CO 2 . It is essential to consider the non-ideality of CO 2 under these conditions if accurate results are to be obtained. There are two main areas where this is relevant: the first is the use of temperature measurements to adjust the measured pressure readings so that the effect of temperature fluctuations is eliminated. The second is in the conversion of the pressure drop data to volumetric leak rate. An example test is described in which it is shown that the CO 2 based temperature correction method improves the accuracy of the pressure drop estimate by about a factor of ten over using a perfect gas assumption and a factor of about 25 over not attempting to adjust the pressure at all. Also the flow rate obtained from assuming the gas was perfect was almost a factor of two too low. A method for scaling leakage rates to other temperature pressures and gases is also given brief consideration in this report. It is observed that the results of scaling are strongly dependent on the flow regime assumed and it is not possible to determine the flow regime from the pressure drop data. Consequently only upper and lower bounds to the scaled estimate can be quoted. (U.K.)

  8. Modelling of accidental releases from a high pressure CO2 pipelines

    NARCIS (Netherlands)

    Molag, M.; Dam, C.

    2011-01-01

    In the near future large quantities of CO2 will be transported over a large distance from Carbon dioxide Capture plants to onshore and off-shore underground Storage (CCS) sites. The risk assessments for the existing CO2 pipelines show distances to harmful threshold concentrations from 1 to 7.2 km.

  9. Ionic Liquid (1-Butyl-3-Metylimidazolium Methane Sulphonate Corrosion and Energy Analysis for High Pressure CO2 Absorption Process

    Directory of Open Access Journals (Sweden)

    Aqeel Ahmad Taimoor

    2018-05-01

    Full Text Available This study explores the possible use of ionic liquids as a solvent in a commercial high-pressure CO2 removal process, to gain environmental and energy benefits. There are two main constraints in realizing this: ionic liquids can be corrosive, specifically when mixed with a water/amine solution with dissolved O2 & CO2; and CO2 absorption within this process is not very well understood. Therefore, scavenging CO2 to ppm levels from process gas comes with several risks. We used 1-butyl-3-methylimidazoium methane sulphonate [bmim][MS] as an ionic liquid because of its high corrosiveness (due to its acidic nature to estimate the ranges of expected corrosion in the process. TAFEL technique was used to determine these rates. Further, the process was simulated based on the conventional absorption–desorption process using ASPEN HYSYS v 8.6. After preliminary model validation with the amine solution, [bmim][MS] was modeled based on the properties found in the literature. The energy comparison was then provided and the optimum ratio of the ionic liquid/amine solution was calculated.

  10. Capillary pressure and saturation relations for supercritical CO2 and brine in sand: High-pressure Pc(Sw) controller/meter measurements and capillary scaling predictions

    Science.gov (United States)

    Tokunaga, Tetsu K.; Wan, Jiamin; Jung, Jong-Won; Kim, Tae Wook; Kim, Yongman; Dong, Wenming

    2013-08-01

    In geologic carbon sequestration, reliable predictions of CO2 storage require understanding the capillary behavior of supercritical (sc) CO2. Given the limited availability of measurements of the capillary pressure (Pc) dependence on water saturation (Sw) with scCO2 as the displacing fluid, simulations of CO2 sequestration commonly rely on modifying more familiar air/H2O and oil/H2O Pc(Sw) relations, adjusted to account for differences in interfacial tensions. In order to test such capillary scaling-based predictions, we developed a high-pressure Pc(Sw) controller/meter, allowing accurate Pc and Sw measurements. Drainage and imbibition processes were measured on quartz sand with scCO2-brine at pressures of 8.5 and 12.0 MPa (45°C), and air-brine at 21°C and 0.1 MPa. Drainage and rewetting at intermediate Sw levels shifted to Pc values that were from 30% to 90% lower than predicted based on interfacial tension changes. Augmenting interfacial tension-based predictions with differences in independently measured contact angles from different sources led to more similar scaled Pc(Sw) relations but still did not converge onto universal drainage and imbibition curves. Equilibrium capillary trapping of the nonwetting phases was determined for Pc = 0 during rewetting. The capillary-trapped volumes for scCO2 were significantly greater than for air. Given that the experiments were all conducted on a system with well-defined pore geometry (homogeneous sand), and that scCO2-brine interfacial tensions are fairly well constrained, we conclude that the observed deviations from scaling predictions resulted from scCO2-induced decreased wettability. Wettability alteration by scCO2 makes predicting hydraulic behavior more challenging than for less reactive fluids.

  11. Influence of CO2 on ultrasound-induced polymerizations in high-pressure fluids

    NARCIS (Netherlands)

    Kuijpers, M.W.A.; Jacobs, L.J.M.; Kemmere, M.F.; Keurentjes, J.T.F.

    2005-01-01

    A strong viscosity increase upon polymerization hinders cavitation and subsequent radical formation during an ultrasound-induced bulk polymerization. Ultrasound-induced radical polymerizations of methyl methacrylate (MMA) have been performed in CO2-expanded MMA, as well as in bulk MMA. For this

  12. A High-Pressure Study of Manganese Metal and its Reactions with CO2 at 6, 23, and 44 GPa

    Science.gov (United States)

    Sawchuk, K. L. S.; McGuire, C. P.; Greenburg, A.; Makhluf, A.; Kavner, A.

    2017-12-01

    The free energies of formation of oxides and carbonates at the extreme pressures and temperatures of Earth's interior provides some of the thermodynamic constrains for models of mantle/core formation and subsequent chemical evolution. The broad goal of our research program is to measure the pressure- and temperature-dependence of free energies of formation of transition metal oxides and carbonates. This requires measurements of the phase stability, density, and thermoelastic properties of metals, oxides, and carbonates at deep-Earth and planetary conditions. Manganese is of interest because it is one of the most abundant transition metal geochemical tracers, it readily forms a carbonate at ambient pressure, and its high-pressure carbonate and oxide densities and equation of state parameters are relatively unknown. Here we report new data on the pressure/volume equation of state and structure of manganese metal as well as its reactions with CO2. These measurements were made using a laser heated diamond anvil cell in conjunction with synchrotron-based X-ray diffraction at beamline 12.2.2 at the Advanced Light Source. Three samples of manganese metal were gas-loaded in a CO2 pressure medium and pressurized to 6, 23, and 44 GPa. Upon laser heating, the CO2 reacted with the Mn metal generating new phases. To analyze the diffraction patterns, we we use a python-based program developed in-house for extracting high resolution 2-dimensional diffraction peak position and intensity information from two-dimensional X-ray diffraction patterns. At each pressure step, the structure and density of the quenched Mn metal phase was determined. At 6 GPa, Mn metal adopts a BCC structure, and at 23 GPa a tetragonal distortion is observed in the lattice. The measured equation of state is in good agreement with an existing meaurement by Fujihisa and Takemura (1995). MnCO3 rhodochrosite is observed in the sample quenched after heating at 6 GPa. Additional high pressure phases are evident

  13. Experimental investigation of convection heat transfer of CO2 at supercritical pressures in a vertical circular tube at high Re

    International Nuclear Information System (INIS)

    Li Zhihui; Jiang Peixue

    2008-01-01

    Convection heat transfer during the upward flow of CO 2 at supercritical pressures in a vertical circular tube (d in = 2 mm) at high Reynolds numbers was investigated experimentally, and the effects of heat fluxes, mass fluxes, inlet temperatures, pressures, buoyancy and thermal acceleration on the convection heat transfer was analyzed. The results show that the tube wall temperature occurs abnormally distribution for high heat-fluxes with upward flow. The degree of deteriorated heat transfer increases with increasing heat flux. Increasing of the mass flux delays the occurrence of the deterioration of heat transfer and weakens the deterioration of heat transfer down-stream section. The inlet temperature strongly influences the heat transfer. The deterioration degree of heat transfer decreases with increasing pressure. (authors)

  14. Flow of CO2 ethanol and of CO2 methanol in a non-adiabatic microfluidic T-junction at high pressures

    NARCIS (Netherlands)

    Blanch Ojea, R.; Tiggelaar, Roald M.; Pallares, J.; Grau, F.X.; Gardeniers, Johannes G.E.

    2012-01-01

    In this work, an experimental investigation of the single- and multiphase flows of two sets of fluids, CO2–ethanol and CO2–methanol, in a non-adiabatic microfluidic T-junction is presented. The operating conditions ranged from 7 to 18 MPa, and from 294 to 474 K. The feed mass fraction of CO2 in the

  15. Potential role of pectate lyase and Ca(2+) in the increase in strawberry fruit firmness induced by short-term treatment with high-pressure CO2.

    Science.gov (United States)

    Wang, Mao Hua; Kim, Jin Gook; Ahn, Sun Eun; Lee, Ah Youn; Bae, Tae Min; Kim, Deu Re; Hwang, Yong Soo

    2014-04-01

    Postharvest treatment with high-pressure CO2 helps to control decay and increase firmness in strawberries. Increases in firmness occurred through modification of calcium binding to cell wall. However, the mechanism(s) involved in Ca(2+) migration to pectic polymers and other physiological events associated with the maintenance of increased firmness are not clearly understood. The focus of this study was to find potential mechanism(s) that are associated with calcium movement, increases in firmness, or maintenance of firmness in strawberry fruit after high-pressure CO2 treatment. An increase in firmness was induced by high-pressure CO2 treatment, but not by high-pressure N2 treatment. This indicates that CO2 stimulates a change in firmness. The increase in firmness induced by high-pressure CO2 seems to involve calcium efflux. Using membrane Ca(2+) -dependent ATPase inhibitors sodium vanadate (250 μM) and erythrosin B (100 μM) delayed both the increase in firmness and calcium binding to wall polymers. Exogenous application of CaCl2 (10 mM) enhanced the firmness increase of fruit slices only when they were exposed to high-pressure CO2 . The activity of pectate lyase was downregulated by CO2 treatment, but β-galactosidase activity was not affected. The increase in strawberry firmness induced by high-pressure CO2 treatment primarily involves the efflux of calcium ions and their binding to wall polymers. These physiological changes are not induced by an anaerobic environment. The downregulation of wall-modifying enzymes, such as pectate lyase, appeared to contribute to the maintenance of firmness that was induced by high-pressure CO2 treatment. © 2014 Institute of Food Technologists®

  16. Biological CO2 conversion to acetate in subsurface coal-sand formation using a high-pressure reactor system

    Directory of Open Access Journals (Sweden)

    Yoko eOhtomo

    2013-12-01

    Full Text Available Geological CO2 sequestration in unmineable subsurface oil/gas fields and coal formations has been proposed as a means of reducing anthropogenic greenhouse gasses in the atmosphere. However, the feasibility of injecting CO2 into subsurface depends upon a variety of geological and economic conditions, and the ecological consequences are largely unpredictable. In this study, we developed a new flow-through-type reactor system to examine potential geophysical, geochemical and microbiological impacts associated with CO2 injection by simulating in situ pressure (0–100 MPa and temperature (0–70°C conditions. Using the reactor system, anaerobic artificial fluid and CO2 (flow rate: 0.002 and 0.00001 mL/min, respectively were continuously supplemented into a column comprised of bituminous coal and sand under a pore pressure of 40 MPa (confined pressure: 41 MPa at 40°C for 56 days. 16S rRNA gene analysis of the bacterial components showed distinct spatial separation of the predominant taxa in the coal and sand over the course of the experiment. Cultivation experiments using sub-sampled fluids revealed that some microbes survived, or were metabolically active, under CO2-rich conditions. However, no methanogens were activated during the experiment, even though hydrogenotrophic and methylotrophic methanogens were obtained from conventional batch-type cultivation at 20°C. During the reactor experiment, the acetate and methanol concentration in the fluids increased while the δ13Cacetate, H2 and CO2 concentrations decreased, indicating the occurrence of homo-acetogenesis. 16S rRNA genes of homo-acetogenic spore-forming bacteria related to the genus Sporomusa were consistently detected from the sandstone after the reactor experiment. Our results suggest that the injection of CO2 into a natural coal-sand formation preferentially stimulates homo-acetogenesis rather than methanogenesis, and that this process is accompanied by biogenic CO2 conversion to

  17. Asymmetric Hollow Fiber Membranes for Separation of CO 2 from Hydrocarbons and Fluorocarbons at High-Pressure Conditions Relevant to C 2 F 4 Polymerization

    KAUST Repository

    Kosuri, Madhava R.

    2009-12-02

    Separation of high-pressure carbon dioxide from fluorocarbons is important for the production of fluoropolymers such as poly(tetrafluoroethylene). Typical polymeric membranes plasticize under high CO2 partial pressure conditions and fail to provide adequate selective separations. Torlon, a polyamide-imide polymer, with the ability to form interchain hydrogen bonding, is shown to provide stability against aggressive CO2 plasticization. Torlon membranes in the form of asymmetric hollow fibers (the most productive form of membranes) are considered for an intended separation of CO 2/C2F4. To avoid safety issues with tetrafluoroethylene (C2F4), which could detonate under testing conditions, safer surrogate mixtures (C2H2F 2 and C2H4) are considered in this paper. Permeation measurements (at 35 °C) indicate that the Torlon membranes are not plasticized even up to 1250 psi of CO2. The membranes provide mixed gas CO2/C2H2F2 and CO 2/C2H4 selectivities of 100 and 30, respectively, at 1250 psi partial pressures of CO2. On the basis of the measured separation performances of CO2/C2H 2F2 and CO2/C2H4 mixtures, the selectivity of the CO2/C2F4 mixture is expected to be greater than 100. Long-term stability studies indicate that the membranes provide stable separations over a period of 5 days at 1250 psi partial pressures of CO2, thereby making the membrane approach attractive. © 2009 American Chemical Society.

  18. Asymmetric Hollow Fiber Membranes for Separation of CO 2 from Hydrocarbons and Fluorocarbons at High-Pressure Conditions Relevant to C 2 F 4 Polymerization

    KAUST Repository

    Kosuri, Madhava R.; Koros, William J.

    2009-01-01

    Separation of high-pressure carbon dioxide from fluorocarbons is important for the production of fluoropolymers such as poly(tetrafluoroethylene). Typical polymeric membranes plasticize under high CO2 partial pressure conditions and fail to provide adequate selective separations. Torlon, a polyamide-imide polymer, with the ability to form interchain hydrogen bonding, is shown to provide stability against aggressive CO2 plasticization. Torlon membranes in the form of asymmetric hollow fibers (the most productive form of membranes) are considered for an intended separation of CO 2/C2F4. To avoid safety issues with tetrafluoroethylene (C2F4), which could detonate under testing conditions, safer surrogate mixtures (C2H2F 2 and C2H4) are considered in this paper. Permeation measurements (at 35 °C) indicate that the Torlon membranes are not plasticized even up to 1250 psi of CO2. The membranes provide mixed gas CO2/C2H2F2 and CO 2/C2H4 selectivities of 100 and 30, respectively, at 1250 psi partial pressures of CO2. On the basis of the measured separation performances of CO2/C2H 2F2 and CO2/C2H4 mixtures, the selectivity of the CO2/C2F4 mixture is expected to be greater than 100. Long-term stability studies indicate that the membranes provide stable separations over a period of 5 days at 1250 psi partial pressures of CO2, thereby making the membrane approach attractive. © 2009 American Chemical Society.

  19. High-Pressure Phase Equilibria in Systems Containing CO2 and Ionic Liquid of the [Cnmim][Tf2N] Type

    OpenAIRE

    Sedláková, Z. (Zuzana); Wagner, Z. (Zdeněk)

    2012-01-01

    In this review, we present a comparison of the high-pressure phase behaviour of binary systems constituted of CO2 and ionic liquids of the [Cn(m)mim][Tf2N] type. The comparative study shows that the solubility of CO2 in ionic liquids of the [Cnmim][Tf2N] type generally increases with increasing pressure and decreasing temperature, but some peculiarities have been observed. The solubility of CO2 in ionic liquid solvents was correlated using the Soave–Redlich–Kwong equation of state. The result...

  20. Highly Efficient Method for the Synthesis of Activated Mesoporous Biocarbons with Extremely High Surface Area for High-Pressure CO2 Adsorption.

    Science.gov (United States)

    Singh, Gurwinder; Lakhi, Kripal S; Kim, In Young; Kim, Sungho; Srivastava, Prashant; Naidu, Ravi; Vinu, Ajayan

    2017-09-06

    A simple and efficient way to synthesize activated mesoporous biocarbons (AMBs) with extremely high BET surface area and large pore volume has been achieved for the first time through a simple solid state activation of freely available biomass, Arundo donax, with zinc chloride. The textural parameters of the AMB can easily be controlled by varying the activation temperature. It is demonstrated that the mesoporosity of AMB can be finely tuned with a simple adjustment of the amount of activating agent. AMB with almost 100% mesoporosity can be achieved using the activating agent and the biomass ratio of 5 and carbonization at 500 °C. Under the optimized conditions, AMB with a BET surface area of 3298 m 2 g -1 and a pore volume of 1.9 cm 3 g -1 can be prepared. While being used as an adsorbent for CO 2 capture, AMB registers an impressively high pressure CO 2 adsorption capacity of 30.2 mmol g -1 at 30 bar which is much higher than that of activated carbon (AC), multiwalled carbon nanotubes (MWCNTs), highly ordered mesoporous carbons, and mesoporous carbon nitrides. AMB also shows high stability with excellent regeneration properties under vacuum and temperatures of up to 250 °C. These impressive textural parameters and high CO 2 adsorption capacity of AMB clearly reveal its potential as a promising adsorbent for high-pressure CO 2 capture and storage application. Also, the simple one-step synthesis strategy outlined in this work would provide a pathway to generate a series of novel mesoporous activated biocarbons from different biomasses.

  1. Equations for calculating hydrogeochemical reactions of minerals and gases such as CO2 at high pressures and temperatures

    Science.gov (United States)

    Appelo, C.A.J.; Parkhurst, David L.; Post, V.E.A.

    2014-01-01

    coefficients for the Peng–Robinson equations are readily available in the literature.The required equations have been implemented in PHREEQC, version 3, and the parameters for calculating the partial molar volumes and fugacity coefficients have been added to the databases that are distributed with PHREEQC. The ease of use and power of the formulation are illustrated by calculating the solubility of CO2 at high pressures and temperatures, and comparing with well-known examples from the geochemical literature. The equations and parameterizations are suitable for wide application in hydrogeochemical systems, especially in the field of carbon capture and storage.

  2. Equations for calculating hydrogeochemical reactions of minerals and gases such as CO2 at high pressures and temperatures

    Science.gov (United States)

    Appelo, C. A. J.; Parkhurst, D. L.; Post, V. E. A.

    2014-01-01

    Peng-Robinson equations are readily available in the literature. The required equations have been implemented in PHREEQC, version 3, and the parameters for calculating the partial molar volumes and fugacity coefficients have been added to the databases that are distributed with PHREEQC. The ease of use and power of the formulation are illustrated by calculating the solubility of CO2 at high pressures and temperatures, and comparing with well-known examples from the geochemical literature. The equations and parameterizations are suitable for wide application in hydrogeochemical systems, especially in the field of carbon capture and storage.

  3. Biological CO2 conversion to acetate in subsurface coal-sand formation using a high-pressure reactor system

    Science.gov (United States)

    Ohtomo, Y.; Ijiri, A.; Ikegawa, Y.; Tsutsumi, M.; Imachi, H.; Uramoto, G.; Hoshino, T.; Morono, Y.; Tanikawa, W.; Hirose, T.; Inagaki, F.

    2013-12-01

    The geological CO2 sequestration into subsurface unmineable oil/gas fields and coal formations has been considered as one of the possible ways to reduce dispersal of anthropogenic greenhouse gasses into the atmosphere. However, feasibility of CO2 injection largely depends on a variety of geological and economical settings, and its ecological consequences have remained largely unpredictable. To address these issues, we developed a new flow-through-type CO2 injection system designated as the 'geobio-reactor system' to examine possible geophysical, geochemical and microbiological impact caused by CO2 injection under in-situ pressure (0-100 MPa) and temperature (0-70°C) conditions. In this study, we investigated Eocene bituminous coal-sandstones in the northwestern Pacific coast, Hokkaido, Japan, using the geobio-reactor system. Anaerobic artificial fluid and CO2 (flow rate: 0.002 and 0.00001 mL/min, respectively) were continuously supplemented into the coal-sand column under the pore pressure of 40 MPa (confined pressure: 41 MPa) at 40°C for 56 days. Molecular analysis of bacterial 16S rRNA genes showed that predominant bacterial components were physically dispersed from coal to sand as the intact form during experiment. Cultivation experiments from sub-sampling fluids indicated that some terrestrial microbes could preserve their survival in subsurface condition. Molecular analysis of archaeal 16S rRNA genes also showed that no methanogens were activated during experiment. We also anaerobically incubated the coal sample using conventional batch-type cultivation technique with a medium for methanogens. After one year of the batch incubation at 20°C, methane could be detected from the cultures except for the acetate-fed culture. The sequence of archaeal 16S rRNA genes via PCR amplification obtained from the H2 plus formate-fed culture was affiliated with a hydrogenotrophic methanogen within the genus Methanobacterium, whereas the methanol plus trimethylamine culture

  4. Nanocrystallization in Al85Ce8Ni5Co2 amorphous alloy obtained by different strain rate during high pressure torsion

    International Nuclear Information System (INIS)

    Henits, P.; Kovacs, Zs.; Schafler, E.; Varga, L.K.; Labar, J.L.; Revesz, A.

    2010-01-01

    In order to elucidate the role of total strain and strain rate during high pressure torsion of Al 85 Ce 8 Ni 5 Co 2 metallic glass, different deformation conditions were applied to devitrify the as-quenched alloy. The disk-shaped specimens were characterized by X-ray diffraction, transmission electron microscopy and thermal analysis.

  5. Raman spectroscopic measurements of CO2 density: Experimental calibration with high-pressure optical cell (HPOC) and fused silica capillary capsule (FSCC) with application to fluid inclusion observations

    Science.gov (United States)

    Wang, X.; Chou, I-Ming; Hu, W.; Burruss, Robert; Sun, Q.; Song, Y.

    2011-01-01

    Raman spectroscopy is a powerful method for the determination of CO2 densities in fluid inclusions, especially for those with small size and/or low fluid density. The relationship between CO2 Fermi diad split (Δ, cm−1) and CO2 density (ρ, g/cm3) has been documented by several previous studies. However, significant discrepancies exist among these studies mainly because of inconsistent calibration procedures and lack of measurements for CO2fluids having densities between 0.21 and 0.75 g/cm3, where liquid and vapor phases coexist near room temperature.In this study, a high-pressure optical cell and fused silica capillary capsules were used to prepare pure CO2 samples with densities between 0.0472 and 1.0060 g/cm3. The measured CO2 Fermi diad splits were calibrated with two well established Raman bands of benzonitrile at 1192.6 and 1598.9 cm−1. The relationship between the CO2 Fermi diad split and density can be represented by: ρ = 47513.64243 − 1374.824414 × Δ + 13.25586152 × Δ2 − 0.04258891551 × Δ3(r2 = 0.99835, σ = 0.0253 g/cm3), and this relationship was tested by synthetic fluid inclusions and natural CO2-rich fluid inclusions. The effects of temperature and the presence of H2O and CH4 on this relationship were also examined.

  6. Source strength and dispersion of CO2 releases from high-pressure pipelines: CFD model using real gas equation of state

    International Nuclear Information System (INIS)

    Liu, Xiong; Godbole, Ajit; Lu, Cheng; Michal, Guillaume; Venton, Philip

    2014-01-01

    Highlights: • Validated CFD models for decompression and dispersion of CO 2 releases from pipelines. • Incorporation of real gas EOS into CFD code for source strength estimation. • Demonstration of better performance of SST k–ω turbulence model for jet flow. • Demonstration of better performance of real gas EOS compared to ideal gas EOS. • Demonstration of superiority of CFD models over a commercial risk assessment package. - Abstract: Transportation of CO 2 in high-pressure pipelines forms a crucial link in the ever-increasing application of Carbon Capture and Storage (CCS) technologies. An unplanned release of CO 2 from a pipeline presents a risk to human and animal populations and the environment. Therefore it is very important to develop a deeper understanding of the atmospheric dispersion of CO 2 before the deployment of CO 2 pipelines, to allow the appropriate safety precautions to be taken. This paper presents a two-stage Computational Fluid Dynamics (CFD) study developed (1) to estimate the source strength, and (2) to simulate the subsequent dispersion of CO 2 in the atmosphere, using the source strength estimated in stage (1). The Peng–Robinson (PR) EOS was incorporated into the CFD code. This enabled accurate modelling of the CO 2 jet to achieve more precise source strength estimates. The two-stage simulation approach also resulted in a reduction in the overall computing time. The CFD models were validated against experimental results from the British Petroleum (BP) CO 2 dispersion trials, and also against results produced by the risk management package Phast. Compared with the measurements, the CFD simulation results showed good agreement in both source strength and dispersion profile predictions. Furthermore, the effect of release direction on the dispersion was studied. The presented research provides a viable method for the assessment of risks associated with CCS

  7. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Science.gov (United States)

    Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng

    2016-01-01

    The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328

  8. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Jianbo Sun

    2016-03-01

    Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.

  9. An Improved CO2-Crude Oil Minimum Miscibility Pressure Correlation

    Directory of Open Access Journals (Sweden)

    Hao Zhang

    2015-01-01

    Full Text Available Minimum miscibility pressure (MMP, which plays an important role in miscible flooding, is a key parameter in determining whether crude oil and gas are completely miscible. On the basis of 210 groups of CO2-crude oil system minimum miscibility pressure data, an improved CO2-crude oil system minimum miscibility pressure correlation was built by modified conjugate gradient method and global optimizing method. The new correlation is a uniform empirical correlation to calculate the MMP for both thin oil and heavy oil and is expressed as a function of reservoir temperature, C7+ molecular weight of crude oil, and mole fractions of volatile components (CH4 and N2 and intermediate components (CO2, H2S, and C2~C6 of crude oil. Compared to the eleven most popular and relatively high-accuracy CO2-oil system MMP correlations in the previous literature by other nine groups of CO2-oil MMP experimental data, which have not been used to develop the new correlation, it is found that the new empirical correlation provides the best reproduction of the nine groups of CO2-oil MMP experimental data with a percentage average absolute relative error (%AARE of 8% and a percentage maximum absolute relative error (%MARE of 21%, respectively.

  10. Study of the effect of pressure on electrolysis of H2O and co-electrolysis of H2O and CO2 at high temperature

    International Nuclear Information System (INIS)

    Bernadet, Lucile

    2016-01-01

    This thesis work investigates the behavior of a solid oxide cell operating under pressure in high temperature steam electrolysis and co-electrolysis mode (H 2 O and CO 2 ). The experimental study of single cell associated with the development of multi-physical models have been set up. The experiments, carried out using an original test bench developed by the CEA-Grenoble on two types of cells between 1 and 10 bar and 700 to 800 C, allowed to identify in both operating modes that the pressure has a positive or negative effect on performance depending on the cell operating point (current, voltage). In addition, gas analyzes performed in co-electrolysis led to detect in situ CH 4 production under pressure. These pressure effects were simulated by models calibrated at atmospheric pressure. Simulations analysis helped identify the pressure dependent mechanisms and propose operating conditions thanks to the establishment of operating maps. (author) [fr

  11. In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.

    Science.gov (United States)

    Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

    2013-01-02

    We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions.

  12. Pressure effect on transport properties of NdCo2

    International Nuclear Information System (INIS)

    Uchima, K; Takaesu, Y; Takeda, M; Flesch, H G; Hedo, M; Nakama, T; Yagasaki, K; Uwatoko, Y; Burkov, A T

    2012-01-01

    Electrical resistivity ρ and thermopower S of the Laves phase compound of NdCo 2 has been investigated at temperatures from 2 K to 300 K. ρ has been measured under pressures up to 8 GPa and S has been measured under pressures up to 3 GPa. The magnetic transition temperature T C obtained by ρ measurement decreases with increasing pressure. The temperature T mim where the thermopower S takes minimum at high temperature region increases linearly with increasing pressure. The high-temperature minimum of S is associated with a sharp peak in density of states related mainly to the Co 3d-electron density. Since the width of an itinerant electronic band depends on the extent of the corresponding overlapping of 3d orbitals, the pressure variation of T min can be attributed to the broadening of the peak width of 3d electron density of states.

  13. Gain measurements in CO2 CW low pressure lasers

    International Nuclear Information System (INIS)

    Rodrigues, N.A.S.; Chanes Junior, J.B.; Jayaram, K.

    1983-01-01

    A series of gain measurements in low pressure CO 2 CW laser were performed in order to study the behaviour of a CO 2 laser ampliflier as a function of pressure and discharge current. A theoretical model, based on rate equations is also presented to describe the laser behaviour and the experimental procedure adopted. (C.L.B.) [pt

  14. CO2 dissolution and its impact on reservoir pressure behavior

    NARCIS (Netherlands)

    Peters, E.; Egberts, P.J.P.; Loeve, D.; Hofstee, C.

    2015-01-01

    Geological storage of CO2 in large, saline aquifers needs to be monitored for safety purposes. In particular the observation of the pressure behavior of a storage site is relevant for the indication of CO2 leakage. However, interpretation of observed pressure is not straightforward in these systems,

  15. HIGH-PRESSURE VAPOR-LIQUID EQUILIBRIUM DATA FOR BINARY AND TERNARY SYSTEMS FORMED BY SUPERCRITICAL CO2, LIMONENE AND LINALOOL

    Directory of Open Access Journals (Sweden)

    MELO S. A. B. VIEIRA DE

    1999-01-01

    Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

  16. Thermal pressure and isochoric thermal conductivity of solid CO2

    International Nuclear Information System (INIS)

    Purs'kij, O.Yi.

    2005-01-01

    The analysis of the correlation between the thermal pressure and the isochoric thermal conductivity of solid CO 2 has been carried out. The temperature dependences of the thermal pressure and isochoric thermal conductivity for samples with various molar volumes have been obtained. The isothermal pressure dependences of the thermal conductivity of solid CO 2 have been calculated. The form of the temperature dependence of the isochoric thermal conductivity taking the thermal pressure into account has been revealed. Behaviour of the isochoric thermal conductivity is explained by phonon-phonon interaction and additional influence of the thermal pressure

  17. Efficient and environmental-friendly dehydration of fructose to 5-hydroxymethyl-2-furfural in water under high pressure of CO2

    NARCIS (Netherlands)

    Motokucho, Suguru; Morikawa, Hiroshi; Nakatani, Hisayuki; Noordover, Bart A.J.

    2016-01-01

    To develop reaction systems of chemical conversion of biomass, fructose was heated in an aqueous medium under pressurized CO2, which caused in situ generation of carbonic acid. It gave 5-hydroxymethyl-2-furfural (HMF) as a dehydration product in good yields. The maximum yield of HMF was 92% in the

  18. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    KAUST Repository

    Swaidan, Raja

    2015-02-01

    A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

  19. A novel high-pressure vessel for simultaneous observations of seismic velocity and in situ CO2 distribution in a porous rock using a medical X-ray CT scanner

    Science.gov (United States)

    Jiang, Lanlan; Nishizawa, Osamu; Zhang, Yi; Park, Hyuck; Xue, Ziqiu

    2016-12-01

    Understanding the relationship between seismic wave velocity or attenuation and CO2 saturation is essential for CO2 storage in deep saline formations. In the present study, we describe a novel upright high-pressure vessel that is designed to keep a rock sample under reservoir conditions and simultaneously image the entire sample using a medical X-ray CT scanner. The pressure vessel is composed of low X-ray absorption materials: a carbon-fibre-enhanced polyetheretherketone (PEEK) cylinder and PEEK vessel closures supported by carbon-fibre-reinforced plastic (CFRP) joists. The temperature was controlled by a carbon-coated film heater and an aramid fibre thermal insulator. The assembled sample cell allows us to obtain high-resolution images of rock samples during CO2 drainage and brine imbibition under reservoir conditions. The rock sample was oriented vertical to the rotation axis of the CT scanner, and seismic wave paths were aligned parallel to the rotation axis to avoid shadows from the acoustic transducers. The reconstructed CO2 distribution images allow us to calculate the CO2 saturation in the first Fresnel zone along the ray path between transducers. A robust relationship between the seismic wave velocity or attenuation and the CO2 saturation in porous rock was obtained from experiments using this pressure vessel.

  20. Effect of high power CO2 and Yb:YAG laser radiation on the characteristics of TIG arc in atmospherical pressure argon and helium

    Science.gov (United States)

    Wu, Shikai; Xiao, Rongshi

    2015-04-01

    The effects of laser radiation on the characteristics of the DC tungsten inert gas (TIG) arc were investigated by applying a high power slab CO2 laser and a Yb:YAG disc laser. Experiment results reveal that the arc voltage-current curve shifts downwards, the arc column expands, and the arc temperature rises while the high power CO2 laser beam vertically interacts with the TIG arc in argon. With the increase of the laser power, the voltage-current curve of the arc shifts downwards more significantly, and the closer the laser beam impingement on the arc to the cathode, the more the decrease in arc voltage. Moreover, the arc column expansion and the arc temperature rise occur mainly in the region between the laser beam incident position and the anode. However, the arc characteristics hardly change in the cases of the CO2 laser-helium arc and YAG laser-arc interactions. The reason is that the inverse Bremsstrahlung absorption coefficients are greatly different due to the different electron densities of the argon and helium arcs and the different wave lengths of CO2 and YAG lasers.

  1. Design of experimental system for supercritical CO2 fracturing under confining pressure conditions

    Science.gov (United States)

    Wang, H.; Lu, Q.; Li, X.; Yang, B.; Zheng, Y.; Shi, L.; Shi, X.

    2018-03-01

    Supercritical CO2 has the characteristics of low viscosity, high diffusion and zero surface tension, and it is considered as a new fluid for non-polluting and non-aqueous fracturing which can be used for shale gas development. Fracturing refers to a method of utilizing the high-pressure fluid to generate fractures in the rock formation so as to improve the oil and gas flow conditions and increase the oil and gas production. In this article, a new type of experimental system for supercritical CO2 fracturing under confining pressure conditions is designed, which is based on characteristics of supercritical CO2, shale reservoir and down-hole environment. The experimental system consists of three sub-systems, including supercritical CO2 generation system, supercritical CO2 fracturing system and data analysis system. It can be used to simulate supercritical CO2 fracturing under geo-stress conditions, thus to study the rock initiation pressure, the formation of the rock fractures, fractured surface morphology and so on. The experimental system has successfully carried out a series of supercritical CO2 fracturing experiments. The experimental results confirm the feasibility of the experimental system and the high efficiency of supercritical CO2 in fracturing tight rocks.

  2. Annual CO2 budget and seasonal CO2 exchange signals at a High Arctic permafrost site on Spitsbergen, Svalbard archipelago

    Science.gov (United States)

    Lüers, J.; Westermann, S.; Piel, K.; Boike, J.

    2014-01-01

    The annual variability of CO2 exchange in most ecosystems is primarily driven by the activities of plants and soil microorganisms. However, little is known about the carbon balance and its controlling factors outside the growing season in arctic regions dominated by soil freeze/thaw-processes, long-lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a High Arctic tundra area on the west coast of Svalbard based on eddy-covariance flux measurements. The annual cumulative CO2 budget is close to zero grams carbon per square meter per year, but shows a very strong seasonal variability. Four major CO2 exchange seasons have been identified. (1) During summer (ground snow-free), the CO2 exchange occurs mainly as a result of biological activity, with a predominance of strong CO2 assimilation by the ecosystem. (2) The autumn (ground snow-free or partly snow-covered) is dominated by CO2 respiration as a result of biological activity. (3) In winter and spring (ground snow-covered), low but persistent CO2 release occur, overlain by considerable CO2 exchange events in both directions associated with changes of air masses and air and atmospheric CO2 pressure. (4) The snow melt season (pattern of snow-free and snow-covered areas), where both, meteorological and biological forcing, resulting in a visible carbon uptake by the high arctic ecosystem. Data related to this article are archived under: http://doi.pangaea.de/10.1594/PANGAEA.809507.

  3. Modern reciprocating compressors for the use of high pressure refrigerants (e.g. R410A, CO2). Criteria for construction and lubricating systems; Moderne zuigercompressoren voor de toepassing van hogedrukkoudemiddelen (zoals R410A, CO2). Eisen aan constructie en smeersystemen

    Energy Technology Data Exchange (ETDEWEB)

    Van der Lande, C. [Uniechemie, Apeldoorn (Netherlands); Grosse-Kracht, R. [Bitzer, Kuehlmaschinenbau, Sindelfingen (Germany)

    2005-09-01

    The use of high pressure refrigerants like R410A (air conditioning and chillers) and CO2 (low temperature cascade in supermarkets) demands changes in the standard fine reciprocating compressors. The design accounts essential criteria like thermodynamic and physical properties and the interaction between refrigerants and applied lubricants. These are high pressures, the mass flow, the vapour density, the high specific cooling capacity, the power consumption and the temperatures of oil and discharge gasses. [Dutch] De toepassing van R410A (in de klimaat-techniek) en CO2 (in lagetemperatuurcascade-installaties voor de supermarkttoepassing) vereist een aanpassing van standaard semi-hermetische zuigercompressoren om de fysische- en thermodynamische eigenschappen van het koudemiddel tot hun recht te laten komen. Dit zijn vooral de optredende drukken, de massastroom, de dampdichtheid, de hoge specifieke koelcapaciteit, het opgenomen vermogen en de olie- en persgastemperatuur.

  4. Rubber muscle actuation with pressurized CO2 from enzyme-catalyzed urea hydrolysis

    Science.gov (United States)

    Sutter, Thomas M.; Dickerson, Matthew B.; Creasy, Terry S.; Justice, Ryan S.

    2013-09-01

    A biologically inspired pneumatic pressure source was designed and sized to supply high pressure CO2(g) to power a rubber muscle actuator. The enzyme urease served to catalyze the hydrolysis of urea, producing CO2(g) that flowed into the actuator. The actuator’s power envelope was quantified by testing actuator response on a custom-built linear-motion rig. Reaction kinetics and available work density were determined by replacing the actuator with a double-action piston and measuring volumetric gas generation against a fixed pressure on the opposing piston. Under the conditions investigated, urease catalyzed the generation of up to 0.81 MPa (117 psi) of CO2(g) in the reactor headspace within 18 min, and the evolved gas produced a maximum work density of 0.65 J ml-1.

  5. Rubber muscle actuation with pressurized CO2 from enzyme-catalyzed urea hydrolysis

    International Nuclear Information System (INIS)

    Sutter, Thomas M; Dickerson, Matthew B; Creasy, Terry S; Justice, Ryan S

    2013-01-01

    A biologically inspired pneumatic pressure source was designed and sized to supply high pressure CO 2(g) to power a rubber muscle actuator. The enzyme urease served to catalyze the hydrolysis of urea, producing CO 2(g) that flowed into the actuator. The actuator’s power envelope was quantified by testing actuator response on a custom-built linear-motion rig. Reaction kinetics and available work density were determined by replacing the actuator with a double-action piston and measuring volumetric gas generation against a fixed pressure on the opposing piston. Under the conditions investigated, urease catalyzed the generation of up to 0.81 MPa (117 psi) of CO 2(g) in the reactor headspace within 18 min, and the evolved gas produced a maximum work density of 0.65 J ml −1 . (paper)

  6. MgCo2-D2 and MgCoNi-D2 systems synthesized at high pressures and interaction mechanism during the HDDR processing

    Directory of Open Access Journals (Sweden)

    Chubin Wan

    2017-02-01

    MgCo2 is a new example of the hydrogen storage alloy, in which a successful HDDR processing results in the reversible formation of the initial intermetallic at much lower temperatures than in the equilibrium phase diagram of the Mg-Co system.

  7. The oxidation of mild steel in high pressure CO2. Paper presented to the Nuclear Engineering Society on Tuesday, 15 November 1977

    International Nuclear Information System (INIS)

    Gleave, C.

    1977-01-01

    The mechanisms of oxidation of mild steels in high pressure carbon dioxide is elucidated. Rimming steel was oxidized sequentially in C 160 2, at 4.1 MPa and 500 0 C. C 180 2 was used as a tracer gas. The distribution of the 18 0 in the oxide scales could be determined by nuclear micro-analytical techniques in order to determine the oxide growth in both protective and breakaway oxide scales. The examination of the data from weight gains and both nuclear and metallurgical techniques is described and discussed. Several conclusions are drawn to explain the mechanism of the corrosion. (U.K.)

  8. Pressure, O2, and CO2, in aquatic Closed Ecological Systems

    Science.gov (United States)

    Taub, Frieda B.; McLaskey, Anna K.

    2013-03-01

    Pressure increased during net photosynthetic O2 production in the light and decreased during respiratory O2 uptake during the dark in aquatic Closed Ecological Systems (CESs) with small head gas volumes. Because most CO2 will be in the liquid phase as bicarbonate and carbonate anions, and CO2 is more soluble than O2, volumes of gaseous CO2 and gaseous O2 will not change in a compensatory manner, leading to the development of pressure. Pressure increases were greatest with nutrient rich medium with NaHCO3 as the carbon source. With more dilute media, pressure was greatest with NaHCO3, and less with cellulose or no-added carbon. Without adequate turbulence, pressure measurements lagged dissolved O2 concentrations by several hours and dark respiration would have been especially underestimated in our systems (250-1000 ml). With adequate turbulence (rotary shaker), pressure measurements and dissolved O2 concentrations generally agreed during lights on/off cycles, but O2 measurements provided more detail. At 20 °C, 29.9 times as much O2 will distribute into the gas phase as in the liquid, per unit volume, as a result of the limited solubility of O2 in water and according to Henry's Law. Thus even a small head gas volume can contain more O2 than a larger volume of water. When both dissolved and gaseous O2 and CO2 are summed, the changes in Total O2 and CO2 are in relatively close agreement when NaHCO3 is the carbon source. These findings disprove an assumption made in some of Taub's earlier research that aquatic CESs would remain at approximately atmospheric pressure because approximately equal molar quantities of O2 and CO2 would exchange during photosynthesis and respiration; this assumption neglected the distribution of O2 between water and gas phases. High pressures can occur when NaHCO3 is the carbon source in nutrient rich media and if head-gas volumes are small relative to the liquid volume; e.g., one "worse case" condition developed 800 mm Hg above atmospheric

  9. Substantial rate enhancements of the esterification reaction of phthalic anhydride with methanol at high pressure and using supercritical CO2 as a co-solvent in a glass microreactor

    NARCIS (Netherlands)

    Benito-Lopez, F.; Tiggelaar, Roald M.; Salblut, K.; Huskens, Jurriaan; Egberink, Richard J.M.; Reinhoudt, David; Gardeniers, Johannes G.E.; Verboom, Willem

    2007-01-01

    The esterification reaction of phthalic anhydride with methanol was performed at different temperatures in a continuous flow glass microreactor at pressures up to 110 bar and using supercritical CO2 as a co-solvent. The design is such that supercritical CO2 can be generated inside the microreactor.

  10. Studies on the structural stability of Co2P2O7 under pressure

    Science.gov (United States)

    Wang, W. P.; Pang, H.; Jin, M. L.; Shen, X.; Yao, Y.; Wang, Y. G.; Li, Y. C.; Li, X. D.; Jin, C. Q.; Yu, R. C.

    2018-05-01

    The crystal structural evolution of Co2P2O7 was studied by using in situ high pressure angle dispersive x-ray diffraction with synchrotron radiation. The results demonstrate that the α phase of Co2P2O7 goes through a partially irreversible structural transformation to β phase under pressure. The pressure is conductive to reduce the longest Cosbnd O bond length of the α phase, and then more uniform Cosbnd O bonds and regular hexagonal arrangement of CoO6 octahedra of the β phase are favored. According to the Birch-Murnaghan equation, the fitted bulk modulus B0 is 158.1(±5.6) GPa for α phase and 276.5(±6.5) GPa for β phase. Furthermore, the first-principles calculations show that these two phases of Co2P2O7 have almost equal total energies, and also have similar band structures and spin-polarized density of states at their ground states. This may be the reason why these two phases of Co2P2O7 can coexist in the pressure released state. It is found that the band gap energies decrease with increasing pressure for both phases.

  11. Vapor-liquid Phase Equilibria for CO2+Tertpentanol Binary System at Elevated Pressures

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO Jian-cheng; YANG Hao; CHEN Kai-xun

    2011-01-01

    Vapor-liquid phase equilibrium data of tertpentanol in carbon dioxide were measured at temperatures of 313.4,323.4,333.5 and 343.5 K and in the pressure range of 4.56-11.44 MPa.The phase equilibium apparatus used in the work was a variable-volume high-pressure cell.The experimental data were reasonably correlated with Peng-Robinson equation of state(PR-EOS) together with van der Waals-2 two-parameter mixing rules.Henry's Law constants and partial molar volumes of CO2 at infinite dilution were estimated with Krichevsky-Kasarnovsky equation,and Henry's Law constants increase with increasing temperature,however,partial molar volumes of CO2 at infinite dilution are negative whose magnitudes decrease with temperature.Partial molar volumes of CO2 and tertpentanol in liquid phase at equilibrium were calculated.

  12. Pitot pressure analyses in CO2 condensing rarefied hypersonic flows

    Science.gov (United States)

    Ozawa, T.; Suzuki, T.; Fujita, K.

    2016-11-01

    In order to improve the accuracy of rarefied aerodynamic prediction, a hypersonic rarefied wind tunnel (HRWT) was developed at Japan Aerospace Exploration Agency. While this wind tunnel has been limited to inert gases, such as nitrogen or argon, we recently extended the capability of HRWT to CO2 hypersonic flows for several Mars missions. Compared to our previous N2 cases, the condensation effect may not be negligible for CO2 rarefied aerodynamic measurements. Thus, in this work, we have utilized both experimental and numerical approaches to investigate the condensation and rarefaction effects in CO2 hypersonic nozzle flows.

  13. CO2–CH4 permeation in high zeolite 4A loading mixed matrix membranes

    KAUST Repository

    Adams, Ryan T.

    2011-02-01

    Mixed matrix membranes (MMMs) with low particle loadings have been shown to improve the properties of pure polymers for many gas separations. Comparatively few reports have been made for high particle loading (≥50vol.%) MMMs. In this work, CO2-CH4 feeds were used to study the potential of 50vol.% zeolite 4A-poly(vinyl acetate) (PVAc) MMMs for natural gas separations. A low CO2 partial pressure mixed feed probed MMM performance below the plasticization pressure of PVAc and a high CO2 partial pressure mixed feed probed MMM performance at industrially relevant conditions above the plasticization pressure.Under both mixed feed conditions at 35°C, substantial improvements in overall separation performance were observed. At low CO2 partial pressures, CO2 permeability roughly doubled with a nearly 50% increase in selectivity versus pure PVAc under the same conditions. For the high CO2 partial pressure feed, CO2 permeability remained effectively unchanged with a 63% increase in selectivity versus pure PVAc. Surprisingly, the performance of these PVAc based MMMs approached the properties of current " upper bound" polymers. Overall, this work shows that significantly improved performance MMMs can be made with traditional techniques from a low cost, low performance polymer without costly adhesion promoters. © 2010.

  14. CO2–CH4 permeation in high zeolite 4A loading mixed matrix membranes

    KAUST Repository

    Adams, Ryan T.; Lee, Jong Suk; Bae, Tae-Hyun; Ward, Jason K.; Johnson, J.R.; Jones, Christopher W.; Nair, Sankar; Koros, William J.

    2011-01-01

    Mixed matrix membranes (MMMs) with low particle loadings have been shown to improve the properties of pure polymers for many gas separations. Comparatively few reports have been made for high particle loading (≥50vol.%) MMMs. In this work, CO2-CH4 feeds were used to study the potential of 50vol.% zeolite 4A-poly(vinyl acetate) (PVAc) MMMs for natural gas separations. A low CO2 partial pressure mixed feed probed MMM performance below the plasticization pressure of PVAc and a high CO2 partial pressure mixed feed probed MMM performance at industrially relevant conditions above the plasticization pressure.Under both mixed feed conditions at 35°C, substantial improvements in overall separation performance were observed. At low CO2 partial pressures, CO2 permeability roughly doubled with a nearly 50% increase in selectivity versus pure PVAc under the same conditions. For the high CO2 partial pressure feed, CO2 permeability remained effectively unchanged with a 63% increase in selectivity versus pure PVAc. Surprisingly, the performance of these PVAc based MMMs approached the properties of current " upper bound" polymers. Overall, this work shows that significantly improved performance MMMs can be made with traditional techniques from a low cost, low performance polymer without costly adhesion promoters. © 2010.

  15. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo

    2010-01-12

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  16. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo; Car, Anja; Funari, S.; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

    2010-01-01

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  17. Effects of CO 2 on a High Performance Hollow-Fiber Membrane for Natural Gas Purification

    KAUST Repository

    Omole, Imona C.

    2010-05-19

    A 6FDA-based, cross-linkable polyimide was characterized in the form of a defect-free asymmetric hollow-fiber membrane. The novel membrane was cross-linked at various temperatures and tested for natural gas purification in the presence of high CO2 partial pressures. The cross-linked membrane material shows high intrinsic separation performance for CO2 and CH4 (selectivity ∼49, CO2 permeability ∼161 barrer, with a feed at 65 psia, 35 °C, and 10% CO2). Cross-linked asymmetric hollow-fiber membranes made from the material show good resistance to CO2-induced plasticization. Carbon dioxide partial pressures as high as ∼400 psia were employed, and the membrane was shown to be promisingly stable under these aggressive conditions. The performance of the membrane was also analyzed using the dual-mode sorption/transport model. © 2010 American Chemical Society.

  18. Application of GC–MS chromatography for the analysis of the oil fractions extracted by supercritical CO2 at high pressure

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Spirov, Pavel; Søgaard, Erik Gydesen

    2013-01-01

    GC–MS chromatographic analysis has been applied for the investigation of the fractions of oil extracted by supercritical carbon dioxide at a temperature of 60 °C and at pressure values ranging from 22 to 56 MPa. The observations revealed, that the whole extraction process is clearly reflected...... in the chromatograms, demonstrating how the heavier hydrocarbon fractions were gradually involved in the extraction process. The shape of the chromatograms alters with increasing pressure from triangle to trapezoid, approaching the shape of the chromatogram of the crude oil. The observation of the fingerprints...

  19. Heat transfer test in a tube using CO2 at supercritical pressures

    International Nuclear Information System (INIS)

    Kim, Hwan Yeol; Kim, Hyungrae; Song, Jin Ho; Cho, Bong Hyun; Bae, Yoon Yeong

    2005-01-01

    Heat transfer test facility, which is named as SPHINX (Supercritical Pressure Heat Transfer Investigation for NeXt Generation), has been constructed in KAERI for the study of heat transfer and pressure drop characteristics in a single tube, single rod and rod bundle at supercritical CO 2 conditions. The tests with supercritical water are difficult it terms of cost and effort, since the critical pressure and temperature of water are as high as 22.12 MPa and 374.14degC. As a substitute for water, CO 2 is selected for the test since the critical pressure and temperature of CO 2 are 7.38 MPa and 31.05degC that are much lower than those of water. This paper describes the design characteristics of the SPHINX and the experimental investigations on the heat transfer and pressure drop of a vertical single tube with an inside diameter of 4.4 mm with upward flow of supercritical CO 2 . The geometry of the single tube is the same as that of Kyushu University test performed with Freon (R22) for the direct comparison of a medium effect. The tests were performed with various heat and mass fluxes at a given pressure. The range of mass flux is 400∼1200 kg/m 2 s and the heat flux is chosen up to 150 kW/m 2 . The selected pressure are 7.75, 8.12, and 8.85 MPa. The test results are investigated and compared with the previous tests. (author)

  20. Compact, High Accuracy CO2 Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop a low cost, robust, highly precise and accurate CO2 monitoring system. This system will...

  1. Compact, High Accuracy CO2 Monitor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase II proposal seeks to develop a low cost, robust, highly precise and accurate CO2 monitoring system. This system will...

  2. Changes in sparkling wine aroma during the second fermentation under CO2 pressure in sealed bottle.

    Science.gov (United States)

    Martínez-García, Rafael; García-Martínez, Teresa; Puig-Pujol, Anna; Mauricio, Juan Carlos; Moreno, Juan

    2017-12-15

    High quality sparkling wine made by the traditional method requires a second alcoholic fermentation of a base wine in sealed bottles, followed by an aging time in contact with yeast lees. The CO 2 overpressure released during this second fermentation has an important effect on the yeast metabolism and therefore on the wine aroma composition. This study focuses on the changes in chemical composition and 43 aroma compounds released by yeast during this fermentation carried out under two pressure conditions. The data were subjected to statistical analysis allowing differentiating between the base wine and the wine samples taken in the middle and at the end of fermentation. The differentiation among wines obtained to the end of fermentation with or without CO 2 pressure is only achieved by a principal component analysis of 15 selected minor compounds (mainly ethyl dodecanoate, ethyl tetradecanoate, hexyl acetate, ethyl butanoate and ethyl isobutanoate). Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Development of high power pulsed CO2 laser

    International Nuclear Information System (INIS)

    Nakai, Sadao; Matoba, Masafumi; Fujita, Hisanori; Daido, Hiroyuki; Inoue, Mitsuo

    1982-01-01

    The inertial nuclear fusion research using pellet implosion has rapidly progressed accompanying laser technique improvement and output increase. As the high output lasers for this purpose, Nd glass lasers or CO 2 lasers are used. The CO 2 lasers possess the characteristics required as reactor lasers, i.e., high efficiency, high frequency repetition, possibility of scale-up and economy. So, the technical development of high power CO 2 lasers assuming also as reactor drivers has been performed at a quick pace together with the research on the improvement of efficiency of pellet implosion by 10 μm laser beam. The Institute of Laser Engineering, Osaka University, stated to build a laser system LEKKO No. 8 of 8 beams and 10 kJ based on the experiences in laser systems LEKKO No. 1 and LEKKO No. 2, and the system LEKKO No. 8 was completed in March, 1981. The operation tests for one year since then has indicated as the laser characteristics that the system performance was as designed initially. This paper reviews the structure, problems and present status of the large scale CO 2 lasers. In other words, the construction of laser system, CO 2 laser proper, oscillator, booster amplifier, prevention of parasitic oscillation, non-linear pulse propagation and fairing of output pulse form, system control and beam alignment, and high power problems are described. The results obtained are to be reported in subsequent issues. (Wakatsuki, Y.)

  4. Change in cap rock porosity triggered by pressure and temperature dependent CO2–water–rock interactions in CO2 storage systems

    Directory of Open Access Journals (Sweden)

    Christina Hemme

    2017-03-01

    Full Text Available Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas emissions. Supercritical CO2 is injected into a reservoir and dissolves in the brine. Under the impact of pressure and temperature (P–T the aqueous species of the CO2-acidified brine diffuse through the cap rock where they trigger CO2–water–rock interactions. These geochemical reactions result in mineral dissolution and precipitation along the CO2 migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap rock. This study focuses on the diffusive mass transport of CO2 along a gradient of decreasing P–T conditions. The process is retraced with a one-dimensional hydrogeochemical reactive mass transport model. The semi-generic hydrogeochemical model is based on chemical equilibrium thermodynamics. Based on a broad variety of scenarios, including different initial mineralogical, chemical and physical parameters, the hydrogeochemical parameters that are most sensitive for safe long-term CO2 storage are identified. The results demonstrate that P–T conditions have the strongest effect on the change in porosity and the effect of both is stronger at high P–T conditions because the solubility of the mineral phases involved depends on P–T conditions. Furthermore, modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine compositions. Nevertheless, a wide range of conditions for safe CO2 storage is identified.

  5. A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2-N2 and CO2-CH4 gas mixtures with high CO2 loading.

    Science.gov (United States)

    Pal, Arun; Chand, Santanu; Elahi, Syed Meheboob; Das, Madhab C

    2017-11-14

    A microporous MOF {[Zn(SDB)(L) 0.5 ]·S} n (IITKGP-5) with a polar pore surface has been constructed by the combination of a V-shaped -SO 2 functionalized organic linker (H 2 SDB = 4,4'-sulfonyldibenzoic acid) with an N-rich spacer (L = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene), forming a network with sql(2,6L1) topology. IITKGP-5 is characterized by TGA, PXRD and single crystal X-ray diffraction. The framework exhibits lozenge-shaped channels of an approximate size of 4.2 × 5.6 Å 2 along the crystallographic b axis with a potential solvent accessible volume of 26%. The activated IITKGP-5a revealed a CO 2 uptake capacity of 56.4 and 49 cm 3 g -1 at 273 K/1 atm and 295 K/1 atm, respectively. On the contrary, it takes up a much smaller amount of CH 4 (17 cm 3 g -1 at 273 K and 13.6 cm 3 g -1 at 295 K) and N 2 (5.5 cm 3 g -1 at 273 K; 4 cm 3 g -1 at 295 K) under 1 atm pressure exhibiting its potential for a highly selective adsorption of CO 2 from flue gas as well as a landfill gas mixture. Based on the ideal adsorbed solution theory (IAST), a CO 2 /N 2 selectivity of 435.5 and a CO 2 /CH 4 selectivity of 151.6 have been realized at 273 K/100 kPa. The values at 295 K are 147.8 for CO 2 /N 2 and 23.8 for CO 2 /CH 4 gas mixtures under 100 kPa. In addition, this MOF nearly approaches the target values proposed for PSA and TSA processes for practical utility exhibiting its prospect for flue gas separation with a CO 2 loading capacity of 2.04 mmol g -1 .

  6. Laser plasma generation of hydrogen-free diamond-like carbon thin films on Zr-2.5Nb CANDU pressure tube materials and silicon wafers with a pulsed high-power CO2 laser

    International Nuclear Information System (INIS)

    Ebrahim, N.A.; Mouris, J.F.; Hoffmann, C.R.J.; Davis, R.W.

    1995-06-01

    We report the first experiments on the laser plasma deposition of hydrogen-free, diamond-like carbon (DLC) films on Zr-2.5Nb CANDU pressure-tube materials and silicon substrates, using the short-pulse, high-power, CO 2 laser in the High-Power Laser Laboratory at Chalk River Laboratories. The films were (AFM). The thin films show the characteristic signature of DLC films in the Raman spectra obtained using a krypton-ion (Kr + ) laser. The Vickers ultra-low-load microhardness tests show hardness of the coated surface of approximately 7000 Kg force mm -2 , which is consistent with the hardness associated with DLC films. AFM examination of the film morphology shows diamond-like crystals distributed throughout the film, with film thicknesses of up to 0.5 μm generated with 50 laser pulses. With significantly more laser pulses, it is expected that very uniform diamond-like films would be produced. These experiments suggest that it should be possible to deposit hydrogen-free, diamond-like films of relevance to nuclear reactor components with a high-power and high-repetition-rate laser facility. (author). 7 refs., 2 tabs., 15 figs

  7. Annual CO2 budget and seasonal CO2 exchange signals at a high Arctic permafrost site on Spitsbergen, Svalbard archipelago

    DEFF Research Database (Denmark)

    Luërs, J.; Westermann, Signe; Piel, K.

    2014-01-01

    -lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a high Arctic tundra area at the west coast of Svalbard based on eddy covariance flux measurements. The annual cumulative CO2 budget is close to 0 g C m-2 yr-1...

  8. Phenol-Formaldehyde Resin-Based Carbons for CO2 Separation at Sub-Atmospheric Pressures

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

    Full Text Available The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO2 than for other gases. In addition to its involvement in climate change, CO2 is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation, in post-combustion processes (flue gas, CO2-N2 and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms as potential adsorbents for CO2 separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO2, H2, N2, and CH4 adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST in conjunction with the Sips model. The CO2 uptakes of the resin-derived carbons from CO2-CH4, CO2-H2, and CO2-N2 at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL. The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO2 separation in post-combustion (flue gas, CO2-N2 and in hydrogen fermentation (CO2-H2, CO2-CH4.

  9. High pressure pure- and mixed-gas separation of CO2/CH4 by thermally-rearranged and carbon molecular sieve membranes derived from a polyimide of intrinsic microporosity

    KAUST Repository

    Swaidan, Raja

    2013-11-01

    Natural gas sweetening, one of the most promising venues for the growth of the membrane gas separation industry, is dominated by polymeric materials with relatively low permeabilities and moderate selectivities. One strategy towards improving the gas transport properties of a polymer is enhancement of microporosity either by design of polymers of intrinsic microporosity (PIMs) or by thermal treatment of polymeric precursors. For the first time, the mixed-gas CO2/CH4 transport properties are investigated for a complete series of thermally-rearranged (TR) (440°C) and carbon molecular sieve (CMS) membranes (600, 630 and 800°C) derived from a polyimide of intrinsic microporosity (PIM-6FDA-OH). The pressure dependence of permeability and selectivity is reported up to 30bar for 1:1, CO2:CH4 mixed-gas feeds at 35°C. The TR membrane exhibited ~15% higher CO2/CH4 selectivity relative to pure-gas feeds due to reductions in mixed-gas CH4 permeability reaching 27% at 30bar. This is attributed to increased hindrance of CH4 transport by co-permeation of CO2. Interestingly, unusual increases in mixed-gas CH4 permeabilities relative to pure-gas values were observed for the CMS membranes, resulting in up to 50% losses in mixed-gas selectivity over the applied pressure range. © 2013 Elsevier B.V.

  10. Thermodynamic and Kinetic Response of Microbial Reactions to High CO2.

    Science.gov (United States)

    Jin, Qusheng; Kirk, Matthew F

    2016-01-01

    Geological carbon sequestration captures CO 2 from industrial sources and stores the CO 2 in subsurface reservoirs, a viable strategy for mitigating global climate change. In assessing the environmental impact of the strategy, a key question is how microbial reactions respond to the elevated CO 2 concentration. This study uses biogeochemical modeling to explore the influence of CO 2 on the thermodynamics and kinetics of common microbial reactions in subsurface environments, including syntrophic oxidation, iron reduction, sulfate reduction, and methanogenesis. The results show that increasing CO 2 levels decreases groundwater pH and modulates chemical speciation of weak acids in groundwater, which in turn affect microbial reactions in different ways and to different extents. Specifically, a thermodynamic analysis shows that increasing CO 2 partial pressure lowers the energy available from syntrophic oxidation and acetoclastic methanogenesis, but raises the available energy of microbial iron reduction, hydrogenotrophic sulfate reduction and methanogenesis. Kinetic modeling suggests that high CO 2 has the potential of inhibiting microbial sulfate reduction while promoting iron reduction. These results are consistent with the observations of previous laboratory and field studies, and highlight the complexity in microbiological responses to elevated CO 2 abundance, and the potential power of biogeochemical modeling in evaluating and quantifying these responses.

  11. Thermodynamic and kinetic response of microbial reactions to high CO2

    Directory of Open Access Journals (Sweden)

    Qusheng Jin

    2016-11-01

    Full Text Available Geological carbon sequestration captures CO2 from industrial sources and stores the CO2 in subsurface reservoirs, a viable strategy for mitigating global climate change. In assessing the environmental impact of the strategy, a key question is how microbial reactions respond to the elevated CO2 concentration. This study uses biogeochemical modeling to explore the influence of CO2 on the thermodynamics and kinetics of common microbial reactions in subsurface environments, including syntrophic oxidation, iron reduction, sulfate reduction, and methanogenesis. The results show that increasing CO2 levels decreases groundwater pH and modulates chemical speciation of weak acids in groundwater, which in turn affect microbial reactions in different ways and to different extents. Specifically, a thermodynamic analysis shows that increasing CO2 partial pressure lowers the energy available from syntrophic oxidation and acetoclastic methanogenesis, but raises the available energy of microbial iron reduction, hydrogenotrophic sulfate reduction and methanogenesis. Kinetic modeling suggests that high CO2 has the potential of inhibiting microbial sulfate reduction while promoting iron reduction. These results are consistent with the observations of previous laboratory and field studies, and highlight the complexity in microbiological responses to elevated CO2 abundance, and the potential power of biogeochemical modeling in evaluating and quantifying these responses.

  12. CO2 as an Oxidant for High Temperature Reactions

    Directory of Open Access Journals (Sweden)

    Sibudjing eKawi

    2015-03-01

    Full Text Available This paper presents a review on the developments in catalyst technology for the reactions utilizing CO2 for high temperature applications. These include dehydrogenation of alkanes to olefins, the dehydrogenation of ethylbenzene to styrene and finally CO2 reforming of hydrocarbon feedstock (i.e. methane and alcohols. Aspects on the various reaction pathways are also highlighted. The literature on the role of promoters and catalyst development is critically evaluated. Most of the reactions discussed in this review are exploited in industries and related to on-going processes, thus providing extensive data from literature. However some reactions, such as CO2 reforming of ethanol and glycerol which have not reached industrial scale are also reviewed owing to their great potential in terms of sustainability which are essential as energy for the future. This review further illustrates the building-up of knowledge which shows the role of support and catalysts for each reaction and the underlying linkage between certain catalysts which can be adapted for the multiple CO2-related reactions.

  13. High-powered CO2 -lasers and noise control

    Science.gov (United States)

    Honkasalo, Antero; Kuronen, Juhani

    High-power CO2 -lasers are being more and more widely used for welding, drilling and cutting in machine shops. In the near future, different kinds of surface treatments will also become routine practice with laser units. The industries benefitting most from high power lasers will be: the automotive industry, shipbuilding, the offshore industry, the aerospace industry, the nuclear and the chemical processing industries. Metal processing lasers are interesting from the point of view of noise control because the working tool is a laser beam. It is reasonable to suppose that the use of such laser beams will lead to lower noise levels than those connected with traditional metal processing methods and equipment. In the following presentation, the noise levels and possible noise-control problems attached to the use of high-powered CO2 -lasers are studied.

  14. Physiological effects on fishes in a high-CO2 world

    Science.gov (United States)

    Ishimatsu, Atsushi; Hayashi, Masahiro; Lee, Kyoung-Seon; Kikkawa, Takashi; Kita, Jun

    2005-09-01

    Fish are important members of both freshwater and marine ecosystems and constitute a major protein source in many countries. Thus potential reduction of fish resources by high-CO2 conditions due to the diffusion of atmospheric CO2 into the surface waters or direct CO2 injection into the deep sea can be considered as another potential threat to the future world population. Fish, and other water-breathing animals, are more susceptible to a rise in environmental CO2 than terrestrial animals because the difference in CO2 partial pressure (PCO2) of the body fluid of water-breathing animals and ambient medium is much smaller (only a few torr (1 torr = 0.1333 kPa = 1316 μatm)) than in terrestrial animals (typically 30-40 torr). A survey of the literature revealed that hypercapnia acutely affects vital physiological functions such as respiration, circulation, and metabolism, and changes in these functions are likely to reduce growth rate and population size through reproduction failure and change the distribution pattern due to avoidance of high-CO2 waters or reduced swimming activities. This paper reviews the acute and chronic effects of CO2 on fish physiology and tries to clarify necessary areas of future research.

  15. Pulse forming networks for fast pumping of high power electron-beam-controlled CO2 lasers

    International Nuclear Information System (INIS)

    Riepe, K.B.

    1975-01-01

    The transverse electric discharge is a widely used technique for pumping CO 2 lasers at high pressures for the generation, simply and efficiently, of very high power laser pulses. The development of the electron-beam-controlled discharge has allowed the application of the transverse discharge to large aperture, very high energy systems. LASL is now in the process of assembly and checkout of a CO 2 laser which is designed to generate a one nanosecond pulse containing 10 kilojoules, for use in laser fusion experiments. The front end of this laser consists of a set of preamplifiers and a mode locked oscillator with electro-optic single pulse switchout. The final amplifier stage consists of four parallel modules, each one consisting of a two-sided electron gun, and two 35 x 35 x 200 cm gas pumping regions operating at a pressure of 1800 torr with a 3/ 1 / 4 /1 (He/N 2 /CO 2 ) laser mix. (auth)

  16. Adsorption of CO2 from flue gas streams by a highly efficient and stable aminosilica adsorbent.

    Science.gov (United States)

    Liu, Shou-Heng; Lin, Yuan-Chung; Chien, Yi-Chi; Hyu, Han-Ren

    2011-02-01

    Three ordered mesoporous silicas (OMSs) with different pore sizes and pore architectures were prepared and modified with amine functional groups by a postgrafting method. The carbon dioxide (CO2) adsorption on these amine-modified OMSs was measured by using microbalances at 348 K, and their adsorption capacities were found to be 0.2-1.4 mmol g(-1) under ambient pressure using dry 15% CO2. It was found experimentally that the CO2 adsorption capacity and adsorption rate were attributed to the density of amine groups and pore volume, respectively. A simple method is described for the production of densely anchored amine groups on a solid adsorbent invoking direct incorporation of tetraethylenepentamine onto the as-synthesized OMSs. Unlike conventional amine-modified OMSs, which typically show CO2 adsorption capacity less than 2 mmol g(-1), such organic template occluded amine-OMS composites possessed remarkably high CO2 uptake of approximately 4.6 mmol g(-1) at 348 K and 1 atm for a dry 15% CO2/nitrogen feed mixture. The enhancement of 8% in CO2 adsorption capacity was also observed in the presence of 10.6% water vapor. Durability tests done by cyclic adsorption-desorption revealed that these adsorbents also possess excellent stability.

  17. Programming MIL-101Cr for selective and enhanced CO2 adsorption at low pressure by postsynthetic amine functionalization.

    Science.gov (United States)

    Khutia, Anupam; Janiak, Christoph

    2014-01-21

    MIL-101Cr fully or partially (p) postsynthetically modified with nitro (-NO2) or amino (-NH2) groups was shown to be a robust, water stable, selective and enhanced carbon dioxide (CO2) adsorption material with the amine-functionality. The highly microporous amine-modified frameworks (up to 1.6 cm(3) g(-1) total pore volume) exhibit excellent thermal stability (>300 °C) with BET surface areas up to 2680 m(2) g(-1). At 1 bar (at 273 K) the gases CO2, CH4 and N2 are adsorbed up to 22.2 wt%, 1.67 wt% and 2.27 wt%, respectively. The two amine-modified MIL-101Cr-NH2 (4) and MIL-101Cr-pNH2 (5) showed the highest gas uptake capacities in the series with high ratios for the CO2 : N2 and CO2 : CH4 selectivities (up to 119 : 1 and 75 : 1, respectively, at 273 K). Comparison with non-modified MIL-101Cr traces the favorable CO2 adsorption properties of MIL-101Cr-NH2 (4) and MIL-101Cr-pNH2 (5) to the presence of the Lewis-basic amine groups. MIL-101Cr-NH2 (4) has a high isosteric heat of adsorption of 43 kJ mol(-1) at zero surface coverage and also >23 kJ mol(-1) over the entire adsorption range, which is well above the heat of liquefaction of bulk CO2. Large CO2 uptake capacities of amine-functionalized 4 and 5, coupled with high adsorption enthalpy, high selectivities and proven long-term water stability, make them suitable candidates for capturing CO2 at low pressure from gas mixtures including the use as a CO2 sorbent from moist air.

  18. Low coral cover in a high-CO2 world

    Science.gov (United States)

    Hoegh-Guldberg, Ove

    2005-09-01

    Coral reefs generally exist within a relatively narrow band of temperatures, light, and seawater aragonite saturation states. The growth of coral reefs is minimal or nonexistent outside this envelope. Climate change, through its effect on ocean temperature, has already had an impact on the world's coral reefs, with almost 30% of corals having disappeared since the beginning of the 1980s. Abnormally warm temperatures cause corals to bleach (lose their brown dinoflagellate symbionts) and, if elevated for long enough, to die. Increasing atmospheric CO2 is also potentially affecting coral reefs by lowering the aragonite saturation state of seawater, making carbonate ions less available for calcification. The synergistic interaction of elevated temperature and CO2 is likely to produce major changes to coral reefs over the next few decades and centuries. Known tolerances of corals to projected changes to sea temperatures indicate that corals are unlikely to remain abundant on reefs and could be rare by the middle of this century if the atmospheric CO2 concentration doubles or triples. The combination of changes to sea temperature and carbonate ion availability could trigger large-scale changes in the biodiversity and function of coral reefs. The ramifications of these changes for the hundred of millions of coral reef-dependent people and industries living in a high-CO2 world have yet to be properly defined. The weight of evidence suggests, however, that projected changes will cause major shifts in the prospects for industries and societies that depend on having healthy coral reefs along their coastlines.

  19. High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples

    Directory of Open Access Journals (Sweden)

    T. K. Bauska

    2014-11-01

    Full Text Available An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2 trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we describe a new technique to determine the δ13C of CO2 at very high precision, as well as measuring the CO2 and N2O mixing ratios. In this method, ancient air is extracted from relatively large ice samples (~400 g with a dry-extraction "ice grater" device. The liberated air is cryogenically purified to a CO2 and N2O mixture and analyzed with a microvolume-equipped dual-inlet IRMS (Thermo MAT 253. The reproducibility of the method, based on replicate analysis of ice core samples, is 0.02‰ for δ13C-CO2 and 2 ppm and 4 ppb for the CO2 and N2O mixing ratios, respectively (1σ pooled standard deviation. Our experiments show that minimizing water vapor pressure in the extraction vessel by housing the grating apparatus in a ultralow-temperature freezer (−60 °C improves the precision and decreases the experimental blank of the method to −0.07 ± 0.04‰. We describe techniques for accurate calibration of small samples and the application of a mass-spectrometric method based on source fragmentation for reconstructing the N2O history of the atmosphere. The oxygen isotopic composition of CO2 is also investigated, confirming previous observations of oxygen exchange between gaseous CO2 and solid H2O within the ice archive. These data offer a possible constraint on oxygen isotopic fractionation during H2O and CO2 exchange below the H2O bulk melting temperature.

  20. Material Processing with High Power CO2-Lasers

    Science.gov (United States)

    Bakowsky, Lothar

    1986-10-01

    After a period of research and development lasertechnique now is regarded as an important instrument for flexible, economic and fully automatic manufacturing. Especially cutting of flat metal sheets with high power C02-lasers and CNC controlled two or three axes handling systems is a wide spread. application. Three dimensional laser cutting, laser-welding and -heat treatment are just at the be ginning of industrial use in production lines. The main. advantages of laser technology. are - high. accuracy - high, processing velocity - law thermal distortion. - no tool abrasion. The market for laser material processing systems had 1985 a volume of 300 Mio S with growth rates between, 20 % and 30 %. The topic of this lecture are hiTrh. power CO2-lasers. Besides this systems two others are used as machining tools, Nd-YAG- and Eximer lasers. All applications of high. power CO2-lasers to industrial material processing show that high processing velocity and quality are only guaranteed in case of a stable intensity. profile on the workpiece. This is only achieved by laser systems without any power and mode fluctuations and by handling systems of high accuracy. Two applications in the automotive industry are described, below as examples for laser cutting and laser welding of special cylindrical motor parts.

  1. Estimating fault stability and sustainable fluid pressures for underground storage of CO2 in porous rock

    International Nuclear Information System (INIS)

    Streit, J.E.; Hillis, R.R.

    2004-01-01

    Geomechanical modelling of fault stability is an integral part of Australia's GEODISC research program to ensure the safe storage of carbon dioxide in subsurface reservoirs. Storage of CO 2 in deep saline formations or depleted hydrocarbon reservoirs requires estimates of sustainable fluid pressures that will not induce fracturing or create fault permeability that could lead to CO 2 escape. Analyses of fault stability require the determination of fault orientations, ambient pore fluid pressures and in situ stresses in a potential storage site. The calculation of effective stresses that act on faults and reservoir rocks lead then to estimates of fault slip tendency and fluid pressures sustainable during CO 2 storage. These parameters can be visualized on 3D images of fault surfaces or in 2D projections. Faults that are unfavourably oriented for reactivation can be identified from failure plots. In depleted oil and gas fields, modelling of fault and rock stability needs to incorporate changes of the pre-production stresses that were induced by hydrocarbon production and associated pore pressure depletion. Such induced stress changes influence the maximum sustainable formation pressures and CO 2 storage volumes. Hence, determination of in situ stresses and modelling of fault stability are essential prerequisites for the safe engineering of subsurface CO 2 injection and the modelling of storage capacity. (author)

  2. Distribution of the partial pressure of CO2 in surface water (pCO2w) between Japan and the Hawaiian Islands: pCO2w-SST relationship in the winter and summer

    International Nuclear Information System (INIS)

    Inoue, Hisayuki Y.; Ishii, Masao; Matsueda, Hidekazu; Kawano, Takeshi; Murata, Akihiko; Takasugi, Yoshio

    2003-01-01

    On the basis of measurements of the partial pressure of carbon dioxide in surface seawater (pCO 2 w) between Japan and the Hawaiian Islands in winter and summer, we examined the relationship between pCO 2 w and the sea surface temperature (SST) in the North Pacific Subtropical Gyre (NPSG). In winter, pCO 2 w correlated well with the SST (0.14-0.24%/deg C), suggesting a monotonous change in the carbonate system. However, in summer, five different pCO 2 w-SST relationships were found in the NPSG (including the Kuroshio Extension) due to changes in the relative contribution of ocean dynamics (upwelling, vertical mixing and advection), biological activity in the absence (very low level) of macro-nutrients and thermodynamics. The increase in pCO 2 w corresponding to a unit increase in the SST from January to July was low (<2.5%/deg C) west (leeward side) of the Hawaiian Islands (19-22 deg N, 158-168 deg W) and in the Kuroshio Extension (33-35 deg N, 140-165deg E), and high (3%/deg C) south of the Kuroshio Extension (25-30 deg N, 180-165 deg W) and the Hawaiian Islands (15-19 deg N, 157-162 deg W). This suggested that the drawdown of dissolved inorganic carbon was affected by the enhanced biological activity due to upwelling events associated with eddies and/or the transport of dissolved nutrients from gyre edges to the interior

  3. Investigational study of the CO2 balance in high temperature CO2 separation technology; Nisanka tanso koon bunri gijutsu ni okeru CO2 balance ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    An investigational study was conducted to clarify the adaptable environment and effectivity of technologies of high temperature separation/recovery/reutilization of CO2. In the study, data collection, arrangement and comparison were made of various separation technologies such as the membrane method, absorption method, adsorption method, and cryogenic separation method. With the LNG-fired power generation as an example, the adaptable environment and effectivity were made clear by making models by a process simulator, ASPEN PLUS. Moreover, using this simulator, effects of replacing the conventional steam reforming of hydrocarbon with the CO2 reforming were made clear with the methanol synthesis as an example. As to the rock fixation treatment of high temperature CO2, collection/arrangement were made of the data on the fixation treatment of the CO2 separated at high temperature into basic rocks such as peridotite and serpentinite in order to clarify the adaptable environment and effectivity of the treatment. Besides, a potentiality of the fixation to concrete waste was made clear. 57 refs., 57 figs., 93 tabs.

  4. High temperature H2/CO2 separation using cobalt oxide silica membranes

    Energy Technology Data Exchange (ETDEWEB)

    Smart, S.; Diniz da Costa, J.C. [The University of Queensland, FIMLab - Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, Qld 4072 (Australia); Vente, J.F. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2012-09-15

    In this work high quality cobalt oxide silica membranes were synthesized on alumina supports using a sol-gel, dip coating method. The membranes were subsequently connected into a steel module using a graphite based proprietary sealing method. The sealed membranes were tested for single gas permeance of He, H2, N2 and CO2 at temperatures up to 600C and feed pressures up to 600 kPa. Pressure tests confirmed that the sealing system was effective as no gas leaks were observed during testing. A H2 permeance of 1.9 x 10{sup -7} mol m{sup -2} s{sup -1} Pa-1 was measured in conjunction with a H2/CO2 permselectivity of more than 1500, suggesting that the membranes had a very narrow pore size distribution and an average pore diameter of approximately 3 Angstrom. The high temperature testing demonstrated that the incorporation of cobalt oxide into the silica matrix produced a structure with a higher thermal stability, able to resist thermally induced densification up to at least 600C. Furthermore, the membranes were tested for H2/CO2 binary feed mixtures between 400 and 600C. At these conditions, the reverse of the water gas shift reaction occurred, inadvertently generating CO and water which increased as a function of CO2 feed concentration. The purity of H2 in the permeate stream significantly decreased for CO2 feed concentrations in excess of 50 vol%. However, the gas mixtures (H2, CO2, CO and water) had a more profound effect on the H2 permeate flow rates which significantly decreased, almost exponentially as the CO2 feed concentration increased.

  5. High power CO2 lasers and their applications in nuclear industry

    International Nuclear Information System (INIS)

    Nath, A.K.

    2002-01-01

    Carbon dioxide laser is one of the most popular lasers in industry for material processing applications. It has very high power capability and high efficiency, can be operated in continuous wave (CW), modulated and pulsed modes, and has relatively low cost. Due to these characteristics high power CO 2 lasers are being used worldwide in different industries for a wide variety of materials processing operations. In nuclear industry, CO 2 laser has made its way in many applications. Some of the tasks performed by multikilowatt CO 2 laser are cutting operations necessary to remove unprocessible hardware from reactor fuel assemblies, sealing/fixing/removing radioactive contaminations onto/from concrete surfaces and surface modification of engineering components for improved surface mechanical and metallurgical characteristics. We have developed various models of CW CO 2 lasers of power up to 12 kW and a high repetitive rate TEA (Transversely Excited Atmospheric pressure) CO 2 laser of 500 W average power operating at 500 Hz repetition rates. We have carried many materials processing applications of direct relevance to DAE. Recent work includes laser welding of end plug PFBR fuel tubes, martensitic stainless steel and titanium alloy, surface cladding of turbine blades made of Ni-super alloy with stellite 694, fabrication on graded material of stainless steel and stellite, and laser scabbling, drilling and cutting of concrete which have potential application in decontamination and decommissioning of nuclear facilities. A brief overview of these indigenous developments will be presented. (author)

  6. Fracture Initiation of an Inhomogeneous Shale Rock under a Pressurized Supercritical CO2 Jet

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2017-10-01

    Full Text Available Due to the advantages of good fracture performance and the application of carbon capture and storage (CCS, supercritical carbon dioxide (SC-CO2 is considered a promising alternative for hydraulic fracturing. However, the fracture initiation mechanism and its propagation under pressurized SC-CO2 jet are still unknown. To address these problems, a fluid–structure interaction (FSI-based numerical simulation model along with a user-defined code was used to investigate the fracture initiation in an inhomogeneous shale rock. The mechanism of fracturing under the effect of SC-CO2 jet was explored, and the effects of various influencing factors were analyzed and discussed. The results indicated that higher velocity jets of SC-CO2 not only caused hydraulic-fracturing ring, but also resulted in the increase of stress in the shale rock. It was found that, with the increase of perforation pressure, more cracks initiated at the tip. In contrast, the length of cracks at the root decreased. The length-to-diameter ratio and the aperture ratio distinctly affected the pressurization of SC-CO2 jet, and contributed to the non-linear distribution and various maximum values of the stress in shale rock. The results proved that Weibull probability distribution was appropriate for analysis of the fracture initiation. The studied parameters explain the distribution of weak elements, and they affect the stress field in shale rock.

  7. Heat transfer test in a vertical tube using CO2 at supercritical pressures

    International Nuclear Information System (INIS)

    Kim, Hwan Yeol; Kim, Hyungrae; Song, Jin Ho; Cho, Bong Hyun; Bae, Yoon Yeong

    2007-01-01

    Heat transfer test facility, SPHINX (Supercritical Pressure Heat Transfer Investigation for NeXt Generation), was constructed at KAERI (Korea Atomic Energy Research Institute) for an investigation of the thermal-hydraulic behaviors of supercritical CO 2 at the various geometries of the test section. The test data will be used for the reactor core design of the SCWR (SuperCritical Water-cooled Reactor). As a working fluid, CO 2 was selected to make use of the low critical pressure and temperature of CO 2 compared with water. An experimental study was carried out in the SPHINX to investigate the characteristics of heat transfer and pressure drop at a vertical single tube with an inside diameter of 4.4 mm in case of an upward flow of supercritical CO 2 . The heat and mass fluxes were varied at a given pressure. The mass flux was in the range of 400-1,200 kg/m 2 s and the heat flux was chosen up to 150 kW/m 2 . The selected pressures were 7.75, 8.12, and 8.85 MPa. A heat transfer deterioration occurred at the lower mass fluxes. The experimental heat transfer coefficients were compared with the ones predicted by several existing correlations. The standard deviation was about 20% for each correlation and an apparent discrepancy was not found among the correlations. The major components of the pressure drop were a gravitational pressure drop and a frictional pressure drop. The frictional pressure drop increases as the mass flux and heat flux increase. (author)

  8. Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

    International Nuclear Information System (INIS)

    Modak, Arindam; Bhaumik, Asim

    2015-01-01

    Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.

  9. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) during BARCA

    Science.gov (United States)

    Chen, H.; Winderlich, J.; Gerbig, C.; Hoefer, A.; Rella, C. W.; Crosson, E. R.; van Pelt, A. D.; Steinbach, J.; Kolle, O.; Beck, V.; Daube, B. C.; Gottlieb, E. W.; Chow, V. Y.; Santoni, G. W.; Wofsy, S. C.

    2009-12-01

    High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

  10. Adaptive management for subsurface pressure and plume control in application to geological CO2 storage

    Science.gov (United States)

    Gonzalez-Nicolas, A.; Cihan, A.; Birkholzer, J. T.; Petrusak, R.; Zhou, Q.; Riestenberg, D. E.; Trautz, R. C.; Godec, M.

    2016-12-01

    Industrial-scale injection of CO2 into the subsurface can cause reservoir pressure increases that must be properly controlled to prevent any potential environmental impact. Excessive pressure buildup in reservoir may result in ground water contamination stemming from leakage through conductive pathways, such as improperly plugged abandoned wells or distant faults, and the potential for fault reactivation and possibly seal breaching. Brine extraction is a viable approach for managing formation pressure, effective stress, and plume movement during industrial-scale CO2 injection projects. The main objectives of this study are to investigate suitable different pressure management strategies involving active brine extraction and passive pressure relief wells. Adaptive optimized management of CO2 storage projects utilizes the advanced automated optimization algorithms and suitable process models. The adaptive management integrates monitoring, forward modeling, inversion modeling and optimization through an iterative process. In this study, we employ an adaptive framework to understand primarily the effects of initial site characterization and frequency of the model update (calibration) and optimization calculations for controlling extraction rates based on the monitoring data on the accuracy and the success of the management without violating pressure buildup constraints in the subsurface reservoir system. We will present results of applying the adaptive framework to test appropriateness of different management strategies for a realistic field injection project.

  11. Pressure effect on electrical resistivity of Y1-xGdxCo2

    International Nuclear Information System (INIS)

    Nakama, T.; Takaesu, Y.; Yagasaki, K.; Sakai, E.; Kurita, N.; Hedo, M.; Uwatoko, Y.; Burkov, A.T.

    2006-01-01

    Electrical resistivity of Y 1-x Gd x Co 2 alloy system has been measured at temperatures from 2 to 300K in magnetic field up to 15T and under pressure up to 10GPa. The compounds with the composition near to phase boundary between paramagnetic and ferromagnetic ground state (x c ∼0.12) show strong enhancement of electrical resistivity at low temperatures. Large positive magnetoresistance was observed in ferromagnetic alloys in composition range 0.15 1-x Gd x Co 2 at low temperatures is in agreement with the variation of magnetoresistance with the composition

  12. Minimized Capillary End Effect During CO2 Displacement in 2-D Micromodel by Manipulating Capillary Pressure at the Outlet Boundary in Lattice Boltzmann Method

    Science.gov (United States)

    Kang, Dong Hun; Yun, Tae Sup

    2018-02-01

    We propose a new outflow boundary condition to minimize the capillary end effect for a pore-scale CO2 displacement simulation. The Rothman-Keller lattice Boltzmann method with multi-relaxation time is implemented to manipulate a nonflat wall and inflow-outflow boundaries with physically acceptable fluid properties in 2-D microfluidic chip domain. Introducing a mean capillary pressure acting at CO2-water interface to the nonwetting fluid at the outlet effectively prevents CO2 injection pressure from suddenly dropping upon CO2 breakthrough such that the continuous CO2 invasion and the increase of CO2 saturation are allowed. This phenomenon becomes most pronounced at capillary number of logCa = -5.5, while capillary fingering and massive displacement of CO2 prevail at low and high capillary numbers, respectively. Simulations with different domain length in homogeneous and heterogeneous domains reveal that capillary pressure and CO2 saturation near the inlet are reproducible compared with those with a proposed boundary condition. The residual CO2 saturation uniquely follows the increasing tendency with increasing capillary number, corroborated by experimental evidences. The determination of the mean capillary pressure and its sensitivity are also discussed. The proposed boundary condition is commonly applicable to other pore-scale simulations to accurately capture the spatial distribution of nonwetting fluid and corresponding displacement ratio.

  13. Calibration of Relative Humidity Devices in Low-pressure, Low-temperature CO2 Environment

    Science.gov (United States)

    Genzer, Maria; Polkko, Jouni; Nikkanen, Timo; Hieta, Maria; Harri, Ari-Matti

    2017-04-01

    Calibration of relative humidity devices requires in minimum two humidity points - dry (0%RH) and (near)saturation (95-100%RH) - over the expected operational temperature and pressure range of the device. In terrestrial applications these are relatively easy to achieve using for example N2 gas as dry medium, and water vapor saturation chambers for producing saturation and intermediate humidity points. But for example in applications intended for meteorological measurements on Mars there is a need to achieve at least dry and saturation points in low-temperature, low-pressure CO2 environment. We have developed a custom-made, small, relatively low-cost calibration chamber able to produce both dry points and saturation points in Martian range pressure CO2, in temperatures down to -70°C. The system utilizes a commercially available temperature chamber for temperature control, vacuum vessels and pumps. The main pressure vessel with the devices under test inside is placed inside the temperature chamber, and the pressure inside is controlled by pumps and manual valves and monitored with a commercial pressure reference with calibration traceable to national standards. Air, CO2, or if needed another gas like N2, is used for filling the vessel until the desired pressure is achieved. Another pressure vessel with a dedicated pressure pump is used as the saturation chamber. This vessel is placed in the room outside the temperature chamber, partly filled with water and used for achieving saturated water vapor in room-temperature low-pressure environment. The saturation chamber is connected to the main pressure vessel via valves. In this system dry point, low-pressure CO2 environment is achieved by filling the main pressure vessel with dry CO2 gas until the desired pressure is achieved. A constant flow of gas is maintained with the pump and valves and monitored with the pressure reference. The saturation point is then achieved by adding some water vapor from the saturation

  14. A perfluorinated covalent triazine-based framework for highly selective and water-tolerant CO2 capture

    KAUST Repository

    Zhao, Yunfeng

    2013-01-01

    We designed and synthesized a perfluorinated covalent triazine-based framework (FCTF-1) for selective CO2 capture. The incorporation of fluorine (F) groups played multiple roles in improving the framework\\'s CO 2 adsorption and separation capabilities. Thermodynamically, the strongly polar C-F bonds promoted CO2 adsorption via electrostatic interactions, especially at low pressures. FCTF-1\\'s CO2 uptake was 1.76 mmol g-1 at 273 K and 0.1 bar through equilibrium adsorption, exceeding the CO2 adsorption capacity of any reported porous organic polymers to date. In addition, incorporating F groups produced a significant amount of ultra-micropores (<0.5 nm), which offered not only high gas adsorption potential but also kinetic selectivity for CO2-N 2 separation. In mixed-gas breakthrough experiments, FCTF-1 exhibited an exceptional CO2-N2 selectivity of 77 under kinetic flow conditions, much higher than the selectivity (31) predicted from single-gas equilibrium adsorption data. Moreover, FCTF-1 proved to be tolerant to water and its CO2 capture performance remained excellent when there was moisture in the gas mixture, due to the hydrophobic nature of the C-F bonds. In addition, the moderate adsorbate-adsorbent interaction allowed it to be fully regenerated by pressure swing adsorption processes. These attributes make FCTF-1 a promising sorbent for CO2 capture from flue gas. © 2013 The Royal Society of Chemistry.

  15. Correlations of CO2 at supercritical pressures in a vertical circular tube

    International Nuclear Information System (INIS)

    Li Zhihui; Jiang Peixue

    2010-01-01

    The experiment results of convection heat transfer of CO 2 at supercritical pressures in a 2 mm diameter vertical circular tube for upward flow and downward flow were analyzed for pressures ranging from 78 to 95 bar, inlet temperatures from to 25 to 40 degree C, and inlet Re numbers from 3000 to 20000. The results were compared with some well known empirical correlations for the heat transfer without buoyancy effects and the heat transfer with strong buoyancy effects. It is found that there is a big deviation between the experiment results and empirical correlations. Based on the experiment data, correlations are developed for the local Nusselt correlations of CO 2 at supercritical pressures in vertical circular tubes.(authors)

  16. Sea anemones may thrive in a high CO2 world.

    Science.gov (United States)

    Suggett, David J; Hall-Spencer, Jason M; Rodolfo-Metalpa, Riccardo; Boatman, Toby G; Payton, Ross; Tye Pettay, D; Johnson, Vivienne R; Warner, Mark E; Lawson, Tracy

    2012-10-01

    Increased seawater pCO 2 , and in turn 'ocean acidification' (OA), is predicted to profoundly impact marine ecosystem diversity and function this century. Much research has already focussed on calcifying reef-forming corals (Class: Anthozoa) that appear particularly susceptible to OA via reduced net calcification. However, here we show that OA-like conditions can simultaneously enhance the ecological success of non-calcifying anthozoans, which not only play key ecological and biogeochemical roles in present day benthic ecosystems but also represent a model organism should calcifying anthozoans exist as less calcified (soft-bodied) forms in future oceans. Increased growth (abundance and size) of the sea anemone (Anemonia viridis) population was observed along a natural CO 2 gradient at Vulcano, Italy. Both gross photosynthesis (P G ) and respiration (R) increased with pCO 2 indicating that the increased growth was, at least in part, fuelled by bottom up (CO 2 stimulation) of metabolism. The increase of P G outweighed that of R and the genetic identity of the symbiotic microalgae (Symbiodinium spp.) remained unchanged (type A19) suggesting proximity to the vent site relieved CO 2 limitation of the anemones' symbiotic microalgal population. Our observations of enhanced productivity with pCO 2 , which are consistent with previous reports for some calcifying corals, convey an increase in fitness that may enable non-calcifying anthozoans to thrive in future environments, i.e. higher seawater pCO 2 . Understanding how CO 2 -enhanced productivity of non- (and less-) calcifying anthozoans applies more widely to tropical ecosystems is a priority where such organisms can dominate benthic ecosystems, in particular following localized anthropogenic stress. © 2012 Blackwell Publishing Ltd.

  17. Modeling of Pressure Dependence of Interfacial Tension Behaviors of Supercritical CO2 + Crude Oil Systems Using a Basic Parachor Expression

    International Nuclear Information System (INIS)

    Dayanand, S.

    2017-01-01

    Parachor based expressions (basic and mechanistic) are often used to model the experimentally observed pressure dependence of interfacial tension behaviors of complex supercritical carbon dioxide (sc-CO 2 ) and crude oil mixtures at elevated temperatures. However, such modeling requires various input data (e.g. compositions and densities of the equilibrium liquid and vapor phases, and molecular weights and diffusion coefficients for various components present in the system). In the absence of measured data, often phase behavior packages are used for obtaining these input data for performing calculations. Very few researchers have used experimentally measured input data for performing parachor based modeling of the experimental interfacial tension behaviors of sc-CO 2 and crude oil systems that are of particular interest to CO 2 injection in porous media based enhanced oil recovery operations. This study presents the results of parachor based modeling performed to predict pressure dependence of interfacial tension behaviors of a complex sc-CO 2 and crude oil system for which experimentally measured data is available in public domain. Though parachor model based on calculated interfacial tension behaviors shows significant deviation from the measured behaviors in high interfacial tension region, difference between the calculated and the experimental behaviors appears to vanish in low interfacial tension region. These observations suggest that basic parachor expression based calculated interfacial tension behaviors in low interfacial tension region follow the experimental interfacial tension behaviors more closely. An analysis of published studies (basic and mechanistic parachor expressions based on modeling of pressure dependence of interfacial tension behaviors of both standard and complex sc-CO 2 and crude oil systems) and the results of this study reinforce the need of better description of gas-oil interactions for robust modeling of pressure dependence of

  18. Experimental investigation of CO2-brine-rock interactions at elevated temperature and pressure: Implications for CO2 sequestration in deep-saline aquifers

    Science.gov (United States)

    Rosenbauer, R.J.; Koksalan, T.; Palandri, J.L.

    2005-01-01

    Deep-saline aquifers are potential repositories for excess CO2, currently being emitted to the atmosphere from anthropogenic activities, but the reactivity of supercritical CO2 with host aquifer fluids and formation minerals needs to be understood. Experiments reacting supercritical CO2 with natural and synthetic brines in the presence and absence of limestone and plagioclase-rich arkosic sandstone showed that the reaction of CO2-saturated brine with limestone results in compositional, mineralogical, and porosity changes in the aquifer fluid and rock that are dependent on initial brine composition, especially dissolved calcium and sulfate. Experiments reacting CO2-saturated, low-sulfate brine with limestone dissolved 10% of the original calcite and increased rock porosity by 2.6%. Experiments reacting high-sulfate brine with limestone, both in the presence and absence of supercritical CO2, were characterized by the precipitation of anhydrite, dolomitization of the limestone, and a final decrease in porosity of 4.5%. However, based on favorable initial porosity changes of about 15% due to the dissolution of calcite, the combination of CO2 co-injection with other mitigation strategies might help alleviate some of the well-bore scale and formation-plugging problems near the injection zone of a brine disposal well in Paradox Valley, Colorado, as well as provide a repository for CO2. Experiments showed that the solubility of CO2 is enhanced in brine in the presence of limestone by 9% at 25 ??C and 6% at 120 ??C and 200 bar relative to the brine itself. The solubility of CO2 is enhanced also in brine in the presence of arkosic sandstone by 5% at 120 ??C and 300 bar. The storage of CO 2 in limestone aquifers is limited to only ionic and hydraulic trapping. However, brine reacted with supercritical CO2 and arkose yielded fixation and sequestration of CO2 in carbonate mineral phases. Brine desiccation was observed in all experiments containing a discrete CO2 phase

  19. Reactor Design for CO2 Photo-Hydrogenation toward Solar Fuels under Ambient Temperature and Pressure

    Directory of Open Access Journals (Sweden)

    Chun-Ying Chen

    2017-02-01

    Full Text Available Photo-hydrogenation of carbon dioxide (CO2 is a green and promising technology and has received much attention recently. This technique could convert solar energy under ambient temperature and pressure into desirable and sustainable solar fuels, such as methanol (CH3OH, methane (CH4, and formic acid (HCOOH. It is worthwhile to mention that this direction can not only potentially depress atmospheric CO2, but also weaken dependence on fossil fuel. Herein, 1 wt % Pt/CuAlGaO4 photocatalyst was successfully synthesized and fully characterized by ultraviolet-visible light (UV-vis spectroscopy, X-ray diffraction (XRD, Field emission scanning electron microscopy using energy dispersive spectroscopy analysis (FE-SEM/EDS, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and Brunauer-Emmett-Teller (BET, respectively. Three kinds of experimental photo-hydrogenation of CO2 in the gas phase, liquid phase, and gas-liquid phase, correspondingly, were conducted under different H2 partial pressures. The remarkable result has been observed in the gas-liquid phase. Additionally, increasing the partial pressure of H2 would enhance the yield of product. However, when an extra amount of H2 is supplied, it might compete with CO2 for occupying the active sites, resulting in a negative effect on CO2 photo-hydrogenation. For liquid and gas-liquid phases, CH3OH is the major product. Maximum total hydrocarbons 8.302 µmol·g−1 is achieved in the gas-liquid phase.

  20. Ethylene: Response of Fruit Dehiscence to CO(2) and Reduced Pressure.

    Science.gov (United States)

    Lipe, J A; Morgan, P W

    1972-12-01

    These studies were conducted to determine whether ethylene serves as a natural regulator of fruit wall dehiscence, a major visible feature of ripening in some fruits. We employed treatments to inhibit ethylene action or remove ethylene and observed their effect on fruit dehiscence. CO(2) (13%), a competitive inhibitor of ethylene action in many systems, readily delayed dehiscence of detached fruits of cotton (Gossypium hirsutum L.), pecan (Carya illinoensis [Wang.] K. Koch), and okra (Hibiscus esculentus L.). The CO(2) effect was duplicated by placing fruits under reduced pressure (200 millimeters mercury), to promote the escape of ethylene from the tissue. Dehiscence of detached fruits of these species as well as attached cotton fruits was delayed. The delay of dehiscence of cotton and okra by both treatments was achieved with fruit harvested at intervals from shortly after anthesis until shortly before natural dehiscence. Pecan fruits would not dehisce until approximately 1 month before natural dehiscence, and during that time, CO(2) and reduced pressure delayed dehiscence. CO(2) and ethylene were competitive in their effects on cotton fruit dehiscence. All of the results are compatible with a hypothetical role of ethylene as a natural regulator of dehiscence, a dominant aspect of ripening of cotton, pecan, and some other fruits.

  1. Ethylene: Response of Fruit Dehiscence to CO2 and Reduced Pressure 1

    Science.gov (United States)

    Lipe, John A.; Morgan, Page W.

    1972-01-01

    These studies were conducted to determine whether ethylene serves as a natural regulator of fruit wall dehiscence, a major visible feature of ripening in some fruits. We employed treatments to inhibit ethylene action or remove ethylene and observed their effect on fruit dehiscence. CO2 (13%), a competitive inhibitor of ethylene action in many systems, readily delayed dehiscence of detached fruits of cotton (Gossypium hirsutum L.), pecan (Carya illinoensis [Wang.] K. Koch), and okra (Hibiscus esculentus L.). The CO2 effect was duplicated by placing fruits under reduced pressure (200 millimeters mercury), to promote the escape of ethylene from the tissue. Dehiscence of detached fruits of these species as well as attached cotton fruits was delayed. The delay of dehiscence of cotton and okra by both treatments was achieved with fruit harvested at intervals from shortly after anthesis until shortly before natural dehiscence. Pecan fruits would not dehisce until approximately 1 month before natural dehiscence, and during that time, CO2 and reduced pressure delayed dehiscence. CO2 and ethylene were competitive in their effects on cotton fruit dehiscence. All of the results are compatible with a hypothetical role of ethylene as a natural regulator of dehiscence, a dominant aspect of ripening of cotton, pecan, and some other fruits. PMID:16658260

  2. In situ X-ray ptychography imaging of high-temperature CO2 acceptor particle agglomerates

    DEFF Research Database (Denmark)

    Høydalsvik, Kristin; Fløystad, Jostein Bø; Zhao, Tiejun

    2014-01-01

    be used for in situ phase contrast imaging in structure studies at atmospheric pressure and elevated temperatures. Lithium zirconate, a candidate CO2 capture material, was studied at a pressure of one atmosphere in air and in CO2, at temperatures exceeding 600 °C. Images with a spatial resolution better...

  3. CO2 reactivity and brain oxygen pressure monitoring in severe head injury.

    Science.gov (United States)

    Carmona Suazo, J A; Maas, A I; van den Brink, W A; van Santbrink, H; Steyerberg, E W; Avezaat, C J

    2000-09-01

    To investigate the effect of hyperventilation on cerebral oxygenation after severe head injury. A prospective, observational study. Neurointensive care unit at a university hospital. A total of 90 patients with severe head injury (Glasgow Coma Scale score brain tissue oxygen pressure (PbrO2) was performed as a measure of cerebral oxygenation. Arterial PCO2 was decreased each day over a 5-day period for 15 mins by increasing minute volume on the ventilator setting to 20% above baseline. Arterial blood gas analysis was performed before and after changing ventilator settings. Multimodality monitoring, including PbrO2, was performed in all patients. Absolute and relative PbrO2/PaCO2 reactivity was calculated. Outcome at 6 months was evaluated according to the Glasgow Outcome Scale. Effective hyperventilation, defined by a decrease of PaCO2 > or =2 torr (0.27 kPa), was obtained in 218 (84%) of 272 tests performed. Baseline PaCO2 averaged 32.3 +/- 4.5 torr (4.31 +/- 0.60 kPa). Average reduction in PaCO2 was 3.8 +/- 1.7 torr (0.51 +/- 0.23 kPa). PbrO2 decreased by 2.8 +/- 3.7 torr (0.37 +/- 0.49 kPa; p < .001) from a baseline value of 26.5 +/- 11.6 torr (3.53 +/- 1.55 kPa). PbrO2/PaCO2 reactivity was low on day 1 (0.8 +/- 2.3 torr [0.11 +/- 0.31 kPa]), increasing on subsequent days to 6.1 +/- 4.4 torr (0.81 +/- 0.59 kPa) on day 5. PbrO2/PaCO2 reactivity on days 1 and 2 was not related to outcome. In later phases in patients with unfavorable outcome, relative reactivity was increased more markedly, reaching statistical significance on day 5. Increased hyperventilation causes a significant reduction in PbrO2, providing further evidence for possible increased risk of secondary ischemic damage during hyperventilation. The low PbrO2/PaCO2 reactivity on day 1 indicates the decreased responsiveness of cerebral microvascular vessels to PaCO2 changes, caused by generalized vascular narrowing. The increasing PbrO2/PaCO2 reactivity from days 2 to 5 suggests that the risk of

  4. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    KAUST Repository

    Swaidan, Raja; Ghanem, Bader; Litwiller, Eric; Pinnau, Ingo

    2015-01-01

    -structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC

  5. Effect of pressure on thermopower and resistivity of EuCo2P2

    International Nuclear Information System (INIS)

    Nakama, T; Yoshida, T; Ohno, A; Nakamura, D; Takaesu, Y; Hedo, M; Yagasaki, K; Uchima, K; Fujiwara, T; Shigeoka, T

    2010-01-01

    The measurements of electrical resistivity ρ and thermopower S of the single-crystalline EuCo 2 P 2 have been performed at temperatures from 2 K to 300 K under hydrostatic pressures up to 3 GPa. The temperature dependence of ρ and S show drastic changes at the critical pressure P c , indicating a large modification of electronic structure around the Fermi level due to a pressure-induced structural and magnetic phase transition. The magnetic phase transition temperature increases linearly with increasing pressure, and shows a sudden increase at the critical pressure P c , which correspond to the change of magnetic state from the localized Eu(4f) sub-lattice magnetism into the itinerant Co(3d) sub-lattice magnetism.

  6. CO2 Reforming of CH4 by Atmospheric Pressure Abnormal Glow Plasma

    International Nuclear Information System (INIS)

    Chen Qi; Dai Wei; Tao Xumei; Yu Hui; Dai Xiaoyan; Yin Yongxiang

    2006-01-01

    A novel plasma atmospheric pressure abnormal glow discharge was used to investigate synthesis gas production from reforming methane and carbon dioxide. Special attentions were paid to the discharge characteristics and CH 4 , CO 2 conversion, H 2 , CO selectivity, and ratio of H 2 /CO varied with the changing of discharging power, the total flux, and the ratio of CH 4 /CO 2 . Experiments were performed in wider operation variables, the discharging power of 240 to 600 W, the CH 4 /CO 2 of 0.2 to 1.0 and the total flux of 140 to 500 mL/min. The experiments showed that the conversion of CH 4 and CO 2 was up to 91.9% and 83.2%, the selectivity of CO and H 2 was also up to 80% and 90% and H 2 /CO mole ratio was 0.2 to 1.2, respectively. A brief analysis for discharge characteristics and the experimental results were given

  7. New CO2 Sensor with High Resolution and Fast Response

    Science.gov (United States)

    2001-10-25

    that a few solid substances selectively adsorb CO2. Combined with a Quartz Micro Balance (QMB) [1, 2] or a Surface Acoustic Wave (SAW) device [3...cardiovascular or respiratory tracts should be sterile or desinfected disposables to minimize the risk for the spread of harmful microorganisms. To

  8. AltitudeOmics: Resetting of cerebrovascular CO2 reactivity following acclimatization to high altitude

    Directory of Open Access Journals (Sweden)

    Jui-Lin eFan

    2016-01-01

    Full Text Available Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv responses to modified rebreathing at sea level (SL, upon ascent (ALT1 and following 16 days of acclimatization (ALT16 to 5,260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95% vs. 129%, SL vs. ALT1, 95% confidence intervals (CI [77, 112], [111, 145], respectively, P=0.024 and the slope of the sigmoid response (4.5 vs. 7.5 %/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P=0.026 to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177%, 95% CI [139, 215], P<0.001; slope: 10.3 %/mmHg, 95% CI [8.2, 12.5], P=0.003 compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P=0.982, while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P=0.001 vs. SL, indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2 following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude.

  9. Measurements of the total CO2 concentration and partial pressure of CO2 in seawater during WOCE expeditions in the South Pacific Ocean

    International Nuclear Information System (INIS)

    Takahashi, T.; Goddard, J.G.; Chipman, D.W.; Rubin, S.I.

    1993-01-01

    During the first year of the grant, we participated in three WOCE expeditions (a total of 152 days at sea) in the South Pacific Ocean, and the field phase of the proposed investigation has been successfully completed. The total CO 2 concentration and pCO 2 were determined at sea in 4419 water samples collected at 422 stations. On the basis of the shipboard analyses of SIO Reference Solutions for CO, and a comparison with the results of previous expeditions, the overall precision of our total CO 2 determinations is estimated to be about ±2 uM/kg. The deep water data indicate that there is a CO 2 maximum centered about 2600 meters deep. This appears to represent a southward return flow from the North Pacific. The magnitude and distribution of the CO, maximum observed along the 135.0 degrees W meridian differ from those observed along the 150.5 degrees W meridian due to Tuamotu Archipelago, a topographic high which interferes with the southward return flow. The surface water pCO 2 data indicate that the South Pacific sub-tropical gyre water located between about 15 degrees S and 50 degrees S is a sink for atmospheric CO 2

  10. Development of ε-insensitive smooth support vector regression for predicting minimum miscibility pressure in CO2 flooding

    Directory of Open Access Journals (Sweden)

    Shahram Mollaiy-Berneti

    2018-02-01

    Full Text Available Successful design of a carbon dioxide (CO2 flooding in enhanced oil recovery projects mostly depends on accurate determination of CO2-crude oil minimum miscibility pressure (MMP. Due to the high expensive and time-consuming of experimental determination of MMP, developing a fast and robust method to predict MMP is necessary. In this study, a new method based on ε-insensitive smooth support vector regression (ε-SSVR is introduced to predict MMP for both pure and impure CO2 gas injection cases. The proposed ε-SSVR is developed using dataset of reservoir temperature, crude oil composition and composition of injected CO2. To serve better understanding of the proposed, feed-forward neural network and radial basis function network applied to denoted dataset. The results show that the suggested ε-SSVR has acceptable reliability and robustness in comparison with two other models. Thus, the proposed method can be considered as an alternative way to monitor the MMP in miscible flooding process.

  11. Light-Triggered CO2 Breathing Foam via Nonsurfactant High Internal Phase Emulsion.

    Science.gov (United States)

    Zhang, Shiming; Wang, Dingguan; Pan, Qianhao; Gui, Qinyuan; Liao, Shenglong; Wang, Yapei

    2017-10-04

    Solid materials for CO 2 capture and storage have attracted enormous attention for gaseous separation, environmental protection, and climate governance. However, their preparation and recovery meet the problems of high energy and financial cost. Herein, a controllable CO 2 capture and storage process is accomplished in an emulsion-templated polymer foam, in which CO 2 is breathed-in under dark and breathed-out under light illumination. Such a process is likely to become a relay of natural CO 2 capture by plants that on the contrary breathe out CO 2 at night. Recyclable CO 2 capture at room temperature and release under light irradiation guarantee its convenient and cost-effective regeneration in industry. Furthermore, CO 2 mixed with CH 4 is successfully separated through this reversible breathing in and out system, which offers great promise for CO 2 enrichment and practical methane purification.

  12. Full Characterization of CO2-Oil Properties On-Chip: Solubility, Diffusivity, Extraction Pressure, Miscibility, and Contact Angle.

    Science.gov (United States)

    Sharbatian, Atena; Abedini, Ali; Qi, ZhenBang; Sinton, David

    2018-02-20

    Carbon capture, storage, and utilization technologies target a reduction in net CO 2 emissions to mitigate greenhouse gas effects. The largest such projects worldwide involve storing CO 2 through enhanced oil recovery-a technologically and economically feasible approach that combines both storage and oil recovery. Successful implementation relies on detailed measurements of CO 2 -oil properties at relevant reservoir conditions (P = 2.0-13.0 MPa and T = 23 and 50 °C). In this paper, we demonstrate a microfluidic method to quantify the comprehensive suite of mutual properties of a CO 2 and crude oil mixture including solubility, diffusivity, extraction pressure, minimum miscibility pressure (MMP), and contact angle. The time-lapse oil swelling/extraction in response to CO 2 exposure under stepwise increasing pressure was quantified via fluorescence microscopy, using the inherent fluorescence property of the oil. The CO 2 solubilities and diffusion coefficients were determined from the swelling process with measurements in strong agreement with previous results. The CO 2 -oil MMP was determined from the subsequent oil extraction process with measurements within 5% of previous values. In addition, the oil-CO 2 -silicon contact angle was measured throughout the process, with contact angle increasing with pressure. In contrast with conventional methods, which require days and ∼500 mL of fluid sample, the approach here provides a comprehensive suite of measurements, 100-fold faster with less than 1 μL of sample, and an opportunity to better inform large-scale CO 2 projects.

  13. High-resolution Atmospheric pCO2 Reconstruction across the Paleogene Using Marine and Terrestrial δ13C records

    Science.gov (United States)

    Cui, Y.; Schubert, B.

    2016-02-01

    The early Paleogene (63 to 47 Ma) is considered to have a greenhouse climate1 with proxies suggesting atmospheric CO2 levels (pCO2) approximately 2× pre-industrial levels. However, the proxy based pCO2 reconstructions are limited and do not allow for assessment of changes in pCO2 at million to sub-million year time scales. It has recently been recognized that changes in C3 land plant carbon isotope fractionation can be used as a proxy for pCO2 with quantifiable uncertainty2. Here, we present a high-resolution pCO2 reconstruction (n = 597) across the early Paleogene using published carbon isotope data from both terrestrial organic matter and marine carbonates. The minimum and maximum pCO2 values reconstructed using this method are broad (i.e., 170 +60/-40 ppmv to 2000 +4480/-1060 ppmv) and reflective of the wide range of environments sampled. However, the large number of measurements allows for a robust estimate of average pCO2 during this time interval ( 400 +260/-120 ppmv), and indicates brief (sub-million-year) excursions to very high pCO2 during hyperthermal events (e.g., the PETM). By binning our high-resolution pCO2 data at 1 million year intervals, we can compare our dataset to the other available pCO2 proxies. Our result is broadly consistent with pCO2 levels reconstructed using other proxies, with the exception of paleosol-based pCO2 estimates spanning 53 to 50 Ma. At this timescale, no proxy suggests pCO2 higher than 2000 ppmv, whereas the global surface ocean temperature is considered to be >10 oC warmer than today. Recent climate modeling suggests that low atmospheric pressure during this time period could help reconcile the apparent disconnect between pCO2 and temperature and contribute to the greenhouse climate3. References1. Huber, M., Caballero, R., 2011. Climate of the Past 7, 603-633. 2. Schubert, B.A., Jahren, A.H., 2015. Geology 43, 435-438. 3. Poulsen, C.J., Tabor, C., White, J.D., 2015. Science 348, 1238-1241.

  14. Adaptive metal mirror for high-power CO2 lasers

    Science.gov (United States)

    Jarosch, Uwe-Klaus

    1996-08-01

    Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

  15. Direct numerical simulation of heat transfer to CO2 at supercritical pressure in a vertical tube

    International Nuclear Information System (INIS)

    Bae, Joong-Hun; Yoo, Jung-Yul; Choi, Hae-Cheon

    2003-01-01

    In the present study, the turbulent heat transfer to CO 2 at supercritical pressure in a vertical tube is investigated using Direct Numerical Simulation (DNS), where no turbulence model is adopted. Heat transfer to the supercritical pressure fluids is characterized by rapid variation of thermodynamic/ thermo-physical properties in the fluids. This change in properties occurs within a very narrow range of temperature across the so-called pseudo-critical temperature, causing a peculiar behavior of heat transfer characteristics. The buoyancy effects associated with very large changes in density proved to play a major role in turbulent heat transfer to supercritical pressure fluids. Depending on the degree of buoyancy effects, turbulent heat transfer may increase or significantly decrease, resulting in a local hot spot along the wall. Based on the results of the present DNS study combined with theoretical considerations for turbulent mixed convection heat transfer, the basic mechanism of this local heat transfer deterioration is explained

  16. Deep Sea Memory of High Atmospheric CO2 Concentration

    Science.gov (United States)

    Mathesius, Sabine; Hofmann, Matthias; Caldeira, Ken; Schellnhuber, Hans Joachim

    2015-04-01

    Carbon dioxide removal (CDR) from the atmosphere has been proposed as a powerful measure to mitigate global warming and ocean acidification. Planetary-scale interventions of that kind are often portrayed as "last-resort strategies", which need to weigh in if humankind keeps on enhancing the climate-system stock of CO2. Yet even if CDR could restore atmospheric CO2 to substantially lower concentrations, would it really qualify to undo the critical impacts of past emissions? In the study presented here, we employed an Earth System Model of Intermediate Complexity (EMIC) to investigate how CDR might erase the emissions legacy in the marine environment, focusing on pH, temperature and dissolved oxygen. Against a background of a world following the RCP8.5 emissions path ("business-as-usual") for centuries, we simulated the effects of two massive CDR interventions with CO2 extraction rates of 5 GtC yr-1 and 25 GtC yr-1, respectively, starting in 2250. We found that the 5 GtC yr-1 scheme would have only minor ameliorative influence on the oceans, even after several centuries of application. By way of contrast, the extreme 25 GtC yr-1 scheme eventually leads to tangible improvements. However, even with such an aggressive measure, past CO2 emissions leave a substantial legacy in the marine environment within the simulated period (i.e., until 2700). In summary, our study demonstrates that anthropogenic alterations of the oceans, caused by continued business-as-usual emissions, may not be reversed on a multi-centennial time scale by the most aspirational geoengineering measures. We also found that a transition from the RCP8.5 state to the state of a strong mitigation scenario (RCP2.6) is not possible, even under the assumption of extreme extraction rates (25 GtC yr-1). This is explicitly demonstrated by simulating additional scenarios, starting CDR already in 2150 and operating until the atmospheric CO2 concentration reaches 280 ppm and 180 ppm, respectively. The simulated

  17. Decontamination of Stainless Steel SS 304 Type with Pressurized CO2 Solid

    International Nuclear Information System (INIS)

    Sutoto

    2007-01-01

    The abrasive decontamination of the stainless steel valve using 12 bar pressurized CO 2 solid has been done. Experiment activities was performed in the HOT CELL facility with variation of blasting time 15, 30, 45 and 60 seconds. The result of experiment shown that the operation of abrasive decontamination during 45 seconds gives the decreasing of the equipment radiation dose rate from 460 to 200 mRem/h and decontamination factor 1.35. The secondary waste from decontamination activities was treated by filtration method using HEPA filter and activated carbon filter. (author)

  18. Isolation and determination of cultural characteristics of a new highly CO2 tolerant fresh water microalgae

    International Nuclear Information System (INIS)

    Yue Lihong; Chen Weigong

    2005-01-01

    Fresh water microalgae, which has high CO 2 tolerance, were isolated and its cultural characteristics were investigated. The ZY-1 strain was identified as genus Chlorella. It showed maximum growth at 10% (v/v) CO 2 enriched air flowing condition, and a good growth rate in a broad range of physically controllable conditions, including CO 2 concentration up to 70% (v/v), CO 2 enriched air flow rate, temperature and pH value. The results indicated the feasibility of the ZY-1 strain for fixing CO 2 from stack gases

  19. Pressurized Martian-Like Pure CO2 Atmosphere Supports Strong Growth of Cyanobacteria, and Causes Significant Changes in their Metabolism

    Science.gov (United States)

    Murukesan, Gayathri; Leino, Hannu; Mäenpää, Pirkko; Ståhle, Kurt; Raksajit, Wuttinun; Lehto, Harry J.; Allahverdiyeva-Rinne, Yagut; Lehto, Kirsi

    2016-03-01

    Surviving of crews during future missions to Mars will depend on reliable and adequate supplies of essential life support materials, i.e. oxygen, food, clean water, and fuel. The most economical and sustainable (and in long term, the only viable) way to provide these supplies on Martian bases is via bio-regenerative systems, by using local resources to drive oxygenic photosynthesis. Selected cyanobacteria, grown in adequately protective containment could serve as pioneer species to produce life sustaining substrates for higher organisms. The very high (95.3 %) CO2 content in Martian atmosphere would provide an abundant carbon source for photo-assimilation, but nitrogen would be a strongly limiting substrate for bio-assimilation in this environment, and would need to be supplemented by nitrogen fertilizing. The very high supply of carbon, with rate-limiting supply of nitrogen strongly affects the growth and the metabolic pathways of the photosynthetic organisms. Here we show that modified, Martian-like atmospheric composition (nearly 100 % CO2) under various low pressure conditions (starting from 50 mbar to maintain liquid water, up to 200 mbars) supports strong cellular growth. Under high CO2 / low N2 ratio the filamentous cyanobacteria produce significant amount of H2 during light due to differentiation of high amount of heterocysts.

  20. Impact of pressure on the dynamic behavior of CO2 hydrate slurry in a stirred tank reactor applied to cold thermal energy storage

    International Nuclear Information System (INIS)

    Dufour, Thomas; Hoang, Hong Minh; Oignet, Jérémy; Osswald, Véronique; Clain, Pascal; Fournaison, Laurence; Delahaye, Anthony

    2017-01-01

    Highlights: •CO 2 hydrate storage was studied in a stirred tank reactor under pressure. •CO 2 hydrates can store three times more energy than water during the same time. •Increasing CO 2 hydrate pressure decreases charge time for the same stored energy. •CO 2 hydrate storage allow average power exchange to be maintained along the process. -- Abstract: Phase change material (PCM) slurries are considered as high-performance fluids for secondary refrigeration and cold thermal energy storage (CTES) systems thanks to their high energy density. Nevertheless, the efficiency of such system is limited by storage dynamic. In fact, PCM charging or discharging rate is governed by system design (storage tank, heat exchanger), heat transfer fluid temperature and flow rate (cold or hot source), and PCM temperature. However, with classical PCM (ice, paraffin…), phase change temperature depends only on material/fluid nature and composition. In the case of gas hydrates, phase change temperature is also controlled by pressure. In the current work, the influence of pressure on cold storage with gas hydrates was studied experimentally using a stirred tank reactor equipped with a cooling jacket. A tank reactor model was also developed to assess the efficiency of this storage process. The results showed that pressure can be used to adjust phase change temperature of CO 2 hydrates, and consequently charging/discharging time. For the same operating conditions and during the same charging time, the amount of stored energy using CO 2 hydrates can be three times higher than that using water. By increasing the initial pressure from 2.45 to 3.2 MPa (at 282.15 K), it is also possible to decrease the charging time by a factor of 3. Finally, it appears that the capacity of pressure to increase CO 2 -hydrate phase-change temperature can also improve system efficiency by decreasing thermal losses.

  1. Effects of high CO2 levels on dynamic photosynthesis: carbon gain, mechanisms, and environmental interactions.

    Science.gov (United States)

    Tomimatsu, Hajime; Tang, Yanhong

    2016-05-01

    Understanding the photosynthetic responses of terrestrial plants to environments with high levels of CO2 is essential to address the ecological effects of elevated atmospheric CO2. Most photosynthetic models used for global carbon issues are based on steady-state photosynthesis, whereby photosynthesis is measured under constant environmental conditions; however, terrestrial plant photosynthesis under natural conditions is highly dynamic, and photosynthetic rates change in response to rapid changes in environmental factors. To predict future contributions of photosynthesis to the global carbon cycle, it is necessary to understand the dynamic nature of photosynthesis in relation to high CO2 levels. In this review, we summarize the current body of knowledge on the photosynthetic response to changes in light intensity under experimentally elevated CO2 conditions. We found that short-term exposure to high CO2 enhances photosynthetic rate, reduces photosynthetic induction time, and reduces post-illumination CO2 burst, resulting in increased leaf carbon gain during dynamic photosynthesis. However, long-term exposure to high CO2 during plant growth has varying effects on dynamic photosynthesis. High levels of CO2 increase the carbon gain in photosynthetic induction in some species, but have no significant effects in other species. Some studies have shown that high CO2 levels reduce the biochemical limitation on RuBP regeneration and Rubisco activation during photosynthetic induction, whereas the effects of high levels of CO2 on stomatal conductance differ among species. Few studies have examined the influence of environmental factors on effects of high levels of CO2 on dynamic photosynthesis. We identified several knowledge gaps that should be addressed to aid future predictions of photosynthesis in high-CO2 environments.

  2. High Efficiency Low Cost CO2 Compression Using Supersonic Shock Wave Technology

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J; Aarnio, M; Grosvenor, A; Taylor, D; Bucher, J

    2010-12-31

    Development and testing results from a supersonic compressor are presented. The compressor achieved record pressure ratio for a fully-supersonic stage and successfully demonstrated the technology potential. Several tasks were performed in compliance with the DOE award objectives. A high-pressure ratio compressor was retrofitted to improve rotordynamics behavior and successfully tested. An outside review panel confirmed test results and design approach. A computational fluid dynamics code used to analyze the Ramgen supersonic flowpath was extensively and successfully modified to improve use on high-performance computing platforms. A comprehensive R&D implementation plan was developed and used to lay the groundwork for a future full-scale compressor demonstration. Conceptual design for a CO2 demonstration compressor was developed and reviewed.

  3. EU's CO2 trade a high risk project

    International Nuclear Information System (INIS)

    Wellander, Dag

    2003-01-01

    The uncertainty about the planned CO 2 trade of the European Union (EU) is very great. For the possible buyers in this politically created market the risks may be great and difficult to assess. The most effective way of forcing a reduction of emissions is trading emission licences. But this requires taking a stand on issues of very unpleasant nature. And the Kyoto protocol evades these questions, it is a thin document right from the beginning. Trade in emission licences is one of the three so-called flexible mechanisms of the Kyoto agreement. The second mechanism is joint implementation in which one industrialized country carries out emission reduction actions in another industrialized country. The third is the mechanism of clean development, in which one industrialized country takes remedial actions in a developing country. It is unclear how these mechanisms are to act in accordance with each other, both in the Kyoto Protocol and on the level of the EU. The biggest and most fundamental uncertainty, both on the EU and global levels, relates to the fact that the partners have not decided how to define the right of ownership of emissions of a certain size

  4. Wet skins tanning with chromium in dense CO2 under pressure

    International Nuclear Information System (INIS)

    Saldinari, L.; Dutel, Ch.; Perre, Ch.

    2000-01-01

    is better adapted to tanning chemistry. The water in the skin quickly absorbs the chromium in suspension. The process of tanning in CO 2 medium was applied in a 10-liter cylindrical autoclave, equipped with an internal rotating basket similar in design to a traditional fuller. The optimum conditions are 80 bar and 37 deg C for pressure and temperature, 15 to 20 minutes impregnation time and 2 hours for basification, modified chromium sulfates as tanning agent, and ACTIPLEX CPS containing sodium bicarbonate as basification agents. The pH of the initial skin was 3, dropping to 2.5 after chromium impregnation and then rising to 5 after basification. The feasibility of chromium tanning in dense CO 2 under pressure was demonstrated. The objectives were achieved: reduction of waste volume and chromium content, reduction of chromium use by better impregnation and fixing, shorter operating time, good end product quality. A patent was filed in October 1999. Pre-industrialization of the process is in the planning stage, with a 100-liter unit built to treat a whole skin. (authors)

  5. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

    Science.gov (United States)

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

  6. High-throughput automated parallel evaluation of zinc-based catalysts for the copolymerization of CHO and CO2 to polycarbonates

    NARCIS (Netherlands)

    Meerendonk, van W.J.; Duchateau, R.; Koning, C.E.; Gruter, G.J.M.

    2004-01-01

    Copolymn. of CO2 and oxiranes using a high-pressure autoclave typically allows one expt. per reactor per day. A high-throughput parallel setup was developed and validated for the copolymn. of CO2 and cyclohxene oxide (CHO) with two b-diiminato zinc complexes. The catalyst activity is affected by

  7. Highly integrated CO2 capture and conversion: Direct synthesis of cyclic carbonates from industrial flue gas

    KAUST Repository

    Barthel, Alexander; Saih, Youssef; Gimenez, Michel; Pelletier, Jeremie; Kü hn, Fritz Elmar; D´ Elia, Valerio; Basset, Jean-Marie

    2016-01-01

    Robust and selective catalytic systems based on early transition metal halides (Y, Sc, Zr) and organic nucleophiles were found able to quantitatively capture CO2 from diluted streams via formation of hemicarbonate species and to convert it to cyclic organic carbonates under ambient conditions. This observation was exploited in the direct and selective chemical fixation of flue gas CO2 collected from an industrial exhaust, affording high degrees of CO2 capture and conversion.

  8. Highly integrated CO2 capture and conversion: Direct synthesis of cyclic carbonates from industrial flue gas

    KAUST Repository

    Barthel, Alexander

    2016-02-08

    Robust and selective catalytic systems based on early transition metal halides (Y, Sc, Zr) and organic nucleophiles were found able to quantitatively capture CO2 from diluted streams via formation of hemicarbonate species and to convert it to cyclic organic carbonates under ambient conditions. This observation was exploited in the direct and selective chemical fixation of flue gas CO2 collected from an industrial exhaust, affording high degrees of CO2 capture and conversion.

  9. Influence of drying methods and agronomic variables on the chemical composition of mate tea leaves (Ilex paraguariensis A. St.-Hil) obtained from high-pressure CO2 extraction.

    Science.gov (United States)

    Jacques, Rosângela Assis; Krause, Laiza Canielas; Freitas, Lisiane dos Santos; Dariva, Cláudio; Oliveira, J Vladimir; Caramão, Elina Bastos

    2007-12-12

    The main objective of this work is to assess the influence of two drying methods (microwave and vacuum oven) and some agronomic variables (plant fertilization conditions and sunlight intensity) on the characteristics of mate tea (Ilex paraguariensis) leaves extracts obtained from high-pressure carbon dioxide extractions performed in the temperature range from 20 to 40 degrees C and from 100 to 250 bar. Samples of mate were collected in an experiment conducted under agronomic control at Ervateira Barão LTDA, Brazil. Chemical distribution of the extracts was evaluated by gas chromatography coupled with a mass spectrometer detector (GC/MS). In addition to extraction variables, results showed that both sample drying methods and agronomic conditions exert a pronounced influence on the extraction yield and on the chemical distribution of the extracts.

  10. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas.

    Science.gov (United States)

    van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

    2016-06-01

    The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant's lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant-plant interactions was analysed. Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant-plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly driven by plastic and not by genotypic responses to changes in

  11. Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

    Science.gov (United States)

    van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

  12. A DC excited waveguide multibeam CO2 laser using high frequency ...

    Indian Academy of Sciences (India)

    High power industrial multibeam CO2 lasers consist of a large number of closely packed ... by producing pre-ionization using an auxiliary high frequency pulsed ... of few kilowatts output power, multibeam technique is used [2]. .... gas mixture of CO2, N2 and He enters in each discharge tube individually from .... Commercial.

  13. Intertidal oysters reach their physiological limit in a future high-CO2 world.

    Science.gov (United States)

    Scanes, Elliot; Parker, Laura M; O'Connor, Wayne A; Stapp, Laura S; Ross, Pauline M

    2017-03-01

    Sessile marine molluscs living in the intertidal zone experience periods of internal acidosis when exposed to air (emersion) during low tide. Relative to other marine organisms, molluscs have been identified as vulnerable to future ocean acidification; however, paradoxically it has also been shown that molluscs exposed to high CO 2 environments are more resilient compared with those molluscs naive to CO 2 exposure. Two competing hypotheses were tested using a novel experimental design incorporating tidal simulations to predict the future intertidal limit of oysters in a high-CO 2 world; either high-shore oysters will be more tolerant of elevated P CO 2 because of their regular acidosis, or elevated P CO 2  will cause high-shore oysters to reach their limit. Sydney rock oysters, Saccostrea glomerata , were collected from the high-intertidal and subtidal areas of the shore and exposed in an orthogonal design to either an intertidal or a subtidal treatment at ambient or elevated P CO 2 , and physiological variables were measured. The combined treatment of tidal emersion and elevated P CO 2  interacted synergistically to reduce the haemolymph pH (pH e ) of oysters, and increase the P CO 2  in the haemolymph ( P e,CO 2 ) and standard metabolic rate. Oysters in the intertidal treatment also had lower condition and growth. Oysters showed a high degree of plasticity, and little evidence was found that intertidal oysters were more resilient than subtidal oysters. It is concluded that in a high-CO 2 world the upper vertical limit of oyster distribution on the shore may be reduced. These results suggest that previous studies on intertidal organisms that lacked tidal simulations may have underestimated the effects of elevated P CO 2 . © 2017. Published by The Company of Biologists Ltd.

  14. Exceptionally High Efficient Co-Co2P@N, P-Codoped Carbon Hybrid Catalyst for Visible Light-Driven CO2-to-CO Conversion.

    Science.gov (United States)

    Fu, Wen Gan

    2018-05-02

    Artificial photosynthesis has attracted wide attention, particularly the development of efficient solar light-driven methods to reduce CO2 to form energy-rich carbon-based products. Because CO2 reduction is an uphill process with a large energy barrier, suitable catalysts are necessary to achieve this transformation. In addition, CO2 adsorption on a catalyst and proton transfer to CO2 are two important factors for the conversion reaction,and catalysts with high surface area and more active sites are required to improve the efficiency of CO2 reduction. Here, we report a visible light-driven system for CO2-to-CO conversion that consists of a heterogeneous hybrid catalyst of Co and Co2P nanoparticles embedded in carbon nanolayers codoped with N and P (Co-Co2P@NPC) and a homogeneous Ru(II)-based complex photosensitizer. The average generation rate of CO of the system was up to 35,000 μmol h-1 g-1 with selectivity of 79.1% in 3 h. Linear CO production at an exceptionally high rate of 63,000 μmol h-1 g-1 was observed in the first hour of reaction. Inspired by this highly active catalyst, we also synthesized Co@NC and Co2P@NPC materials and explored their structure, morphology, and catalytic properties for CO2 photoreduction. The results showed that the nanoparticle size, partially adsorbed H2O molecules on the catalyst surface, and the hybrid nature of the systems influenced their photocatalytic CO2 reduction performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Spatial and Temporal Variations in the Partial Pressure and Emission of CO2 and CH4 in and Amazon Floodplain Lake

    Science.gov (United States)

    Forsberg, B. R.; Amaral, J. H.; Barbosa, P.; Kasper, D.; MacIntyre, S.; Cortes, A.; Sarmento, H.; Borges, A. V.; Melack, J. M.; Farjalla, V.

    2015-12-01

    The Amazon floodplain contains a variety of wetland environments which contribute CO2 and CH4 to the regional and global atmospheres. The partial pressure and emission of these greenhouse gases (GHGs) varies: 1) between habitats, 2) seasonally, as the characteristics these habitats changes and 3) diurnally, in response to diurnal stratification. In this study, we investigated the combined influence of these factors on the partial pressure and emission of GHGs in Lago Janauacá, a central Amazon floodplain lake (3o23' S; 60o18' O). All measurements were made between August of 2014 and April of 2015 at two different sites and in three distinct habitats: open water, flooded forest, flooded macrophytes. Concentrations of CO2 and CH4 in air were measured continuously with a cavity enhanced absorption spectrometer, Los Gatos Research´s Ultraportable Greenhouse Gas Analyzer (UGGA). Vertical profiles o pCO2 and pCH4 were measured using the UGGA connected to an electric pump and equilibrator. Diffusive surface emissions were estimated with the UGGA connected to a static floating chamber. To investigate the influence of vertical stratification and mixing on GHG partial pressure and emissions, a meteorological station and submersible sensor chain were deployed at each site. Meteorological sensors included wind speed and direction. The submersible chains included thermistors and oxygen sensors. Depth profiles of partial pressure and diffusive emissions for both CO2 and CH4 varied diurnally, seasonally and between habitats. Both pCO2 and pCH4 were consistently higher in bottom than surface waters with the largest differences occurring at high water when thermal stratification was most stable. Methane emissions and partial pressures were highest at low water while pCO2 and CO2 fluxes were highest during high water periods, with 35% of CO2 fluxes at low water being negative. The highest average surface value of pCO2 (5491 μatm), encountered during rising water, was ~3 times

  16. Sulfonate-grafted porous polymer networks for preferential CO(2) adsorption at low pressure

    NARCIS (Netherlands)

    Lu, W.; Yuan, D.; Sculley, J.; Zhao, D.; Krishna, R.; Zhou, H.-C.

    2011-01-01

    A porous polymer network (PPN) grafted with sulfonic acid (PPN-6-SO3H) and its lithium salt (PPN-6-SO3Li) exhibit significant increases in isosteric heats of CO2 adsorption and CO2-uptake capacities. IAST calculations using single-component-isotherm data and a 15/85 CO2/N2 ratio at 295 K and 1 bar

  17. High-resolution transmission measurements of CO2 at high temperatures for industrial applications

    DEFF Research Database (Denmark)

    Evseev, Vadim; Fateev, Alexander; Clausen, Sønnik

    2012-01-01

    . The spectra have been recorded in a high-temperature flow gas cell and using a Fourier transform infrared (FTIR) spectrometer at a nominal resolution of 0.125 cm-1. The volume fractions of CO2 in the measurements were 1,10 and 100%. The measurements have been validated by comparison with medium...

  18. High CO2 Primes Plant Biotic Stress Defences through Redox-Linked Pathways.

    Science.gov (United States)

    Mhamdi, Amna; Noctor, Graham

    2016-10-01

    Industrial activities have caused tropospheric CO 2 concentrations to increase over the last two centuries, a trend that is predicted to continue for at least the next several decades. Here, we report that growth of plants in a CO 2 -enriched environment activates responses that are central to defense against pathogenic attack. Salicylic acid accumulation was triggered by high-growth CO 2 in Arabidopsis (Arabidopsis thaliana) and other plants such as bean (Phaseolus vulgaris). A detailed analysis in Arabidopsis revealed that elevated CO 2 primes multiple defense pathways, leading to increased resistance to bacterial and fungal challenge. Analysis of gene-specific mutants provided no evidence that activation of plant defense pathways by high CO 2 was caused by stomatal closure. Rather, the activation is partly linked to metabolic effects involving redox signaling. In support of this, genetic modification of redox components (glutathione contents and NADPH-generating enzymes) prevents full priming of the salicylic acid pathway and associated resistance by high CO 2 The data point to a particularly influential role for the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase, a cytosolic enzyme whose role in plants remains unclear. Our observations add new information on relationships between high CO 2 and oxidative signaling and provide novel insight into plant stress responses in conditions of increased CO 2 . © 2016 American Society of Plant Biologists. All Rights Reserved.

  19. Interactive effects of high CO2 and SO2 on growth and antioxidant levels in wheat

    NARCIS (Netherlands)

    Rao, M.V.; De Kok, L.J.

    1994-01-01

    The impact of elevated CO2 and/or SO2 on the growth and antioxidant levels of wheat {Triticum aestivum L. cv. Urban) plants has been studied. High CO2 (0.7 ml I-1) significantly enhanced shoot biomass and photosynthetic capacity, while exposure to SO2 (0.14 ul I-1) resulted in a decreased shoot

  20. High CO2 Primes Plant Biotic Stress Defences through Redox-Linked Pathways1[OPEN

    Science.gov (United States)

    2016-01-01

    Industrial activities have caused tropospheric CO2 concentrations to increase over the last two centuries, a trend that is predicted to continue for at least the next several decades. Here, we report that growth of plants in a CO2-enriched environment activates responses that are central to defense against pathogenic attack. Salicylic acid accumulation was triggered by high-growth CO2 in Arabidopsis (Arabidopsis thaliana) and other plants such as bean (Phaseolus vulgaris). A detailed analysis in Arabidopsis revealed that elevated CO2 primes multiple defense pathways, leading to increased resistance to bacterial and fungal challenge. Analysis of gene-specific mutants provided no evidence that activation of plant defense pathways by high CO2 was caused by stomatal closure. Rather, the activation is partly linked to metabolic effects involving redox signaling. In support of this, genetic modification of redox components (glutathione contents and NADPH-generating enzymes) prevents full priming of the salicylic acid pathway and associated resistance by high CO2. The data point to a particularly influential role for the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase, a cytosolic enzyme whose role in plants remains unclear. Our observations add new information on relationships between high CO2 and oxidative signaling and provide novel insight into plant stress responses in conditions of increased CO2. PMID:27578552

  1. CO2-Tea pulse clipping using pulsed high voltage preionization for high spatial resolution I.R. Lidar systems

    Directory of Open Access Journals (Sweden)

    Gasmi Taieb

    2018-01-01

    Full Text Available An extra-cavity CO2-TEA laser pulse clipper for high spatial resolution atmospheric monitoring is presented. The clipper uses pulsed high voltageto facilitate the breakdown of the gas within the clipper cell. Complete extinction of the nitrogen tail, that degrades the range resolution of LIDARS, is obtained at pressures from 375 up to 1500 Torr for nitrogen and argon gases whereas an attenuation coefficient of almost 102 is achieved for helium. Excellent energy stability and pulse width repeatability were achieved using high voltage pre-ionized gas technique.

  2. CO2-Tea pulse clipping using pulsed high voltage preionization for high spatial resolution I.R. Lidar systems

    Science.gov (United States)

    Gasmi, Taieb

    2018-04-01

    An extra-cavity CO2-TEA laser pulse clipper for high spatial resolution atmospheric monitoring is presented. The clipper uses pulsed high voltageto facilitate the breakdown of the gas within the clipper cell. Complete extinction of the nitrogen tail, that degrades the range resolution of LIDARS, is obtained at pressures from 375 up to 1500 Torr for nitrogen and argon gases whereas an attenuation coefficient of almost 102 is achieved for helium. Excellent energy stability and pulse width repeatability were achieved using high voltage pre-ionized gas technique.

  3. Heat Transfer Characteristics for an Upward Flowing Supercritical Pressure CO2 in a Vertical Annulus Passage

    International Nuclear Information System (INIS)

    Kang, Deog Ji; Kim, Sin; Kim, Hwan Yeol; Bae, Yoon Yeong

    2007-01-01

    Heat transfer experiments at a vertical annulus passage were carried out in the SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt Generation) to investigate the heat transfer behaviors of supercritical CO 2 . The collected test data are to be used for the reactor core design of the SCWR (SuperCritical Water-cooled Reactor). The mass flux was in the range of 400 ∼1200 kg/m 2 s and the heat flux was chosen up to 150 kW/m 2 . The selected pressures were 7.75 and 8.12 MPa. The heat transfer data were analyzed and compared with the previous tube test data. The test results showed that the heat transfer characteristics were similar to those of the tube in case of a normal heat transfer mode and degree of heat transfer deterioration became smaller than that in the tube. Comparison of the experimental heat transfer coefficients with the predicted ones by the existing correlations showed that there was not a distinct difference between the correlations

  4. Characterization of the CO2 fluid adsorption in coal as a function of pressure using neutron scattering techniques (SANS and USANS)

    Science.gov (United States)

    Melnichenko, Y.B.; Radlinski, A.P.; Mastalerz, Maria; Cheng, G.; Rupp, J.

    2009-01-01

    Small angle neutron scattering techniques have been applied to investigate the phase behavior of CO2 injected into coal and possible changes in the coal pore structure that may result from this injection. Three coals were selected for this study: the Seelyville coal from the Illinois Basin (Ro = 0.53%), Baralaba coal from the Bowen Basin (Ro = 0.67%), and Bulli 4 coal from the Sydney Basin (Ro = 1.42%). The coals were selected from different depths to represent the range of the underground CO2 conditions (from subcritical to supercritical) which may be realized in the deep subsurface environment. The experiments were conducted in a high pressure cell and CO2 was injected under a range of pressure conditions, including those corresponding to in-situ hydrostatic subsurface conditions for each coal. Our experiments indicate that the porous matrix of all coals remains essentially unchanged after exposure to CO2 at pressures up to 200??bar (1??bar = 105??Pa). Each coal responds differently to the CO2 exposure and this response appears to be different in pores of various sizes within the same coal. For the Seelyville coal at reservoir conditions (16????C, 50??bar), CO2 condenses from a gas into liquid, which leads to increased average fluid density in the pores (??pore) with sizes (r) 1 ?? 105 ??? r ??? 1 ?? 104???? (??pore ??? 0.489??g/cm3) as well as in small pores with size between 30 and 300???? (??pore ??? 0.671??g/cm3). These values are by a factor of three to four higher than the density of bulk CO2 (??CO2) under similar thermodynamic conditions (??CO2 ??? 0.15??g/cm3). At the same time, in the intermediate size pores with r ??? 1000???? the average fluid density is similar to the density of bulk fluid, which indicates that adsorption does not occur in these pores. At in situ conditions for the Baralaba coal (35 OC, 100??bar), the average fluid density of CO2 in all pores is lower than that of the bulk fluid (??pore / ??CO2 ??? 0.6). Neutron scattering from the

  5. Atmospheric constraints for the CO2 partial pressure on terrestrial planets near the outer edge of the habitable zone

    OpenAIRE

    von Paris, P.; Grenfell, J. L.; Hedelt, P.; Rauer, H.; Selsis, F.; Stracke, B.

    2013-01-01

    In recent years, several potentially habitable, probably terrestrial exoplanets and exoplanet candidates have been discovered. The amount of CO2 in their atmosphere is of great importance for surface conditions and habitability. In the absence of detailed information on the geochemistry of the planet, this amount could be considered as a free parameter. Up to now, CO2 partial pressures for terrestrial planets have been obtained assuming an available volatile reservoir and outgassing scenarios...

  6. An experimental study of relative permeability hysteresis, capillary trapping characteristics, and capillary pressure of CO2/brine systems at reservoir conditions

    Science.gov (United States)

    Akbarabadi, Morteza

    We present the results of an extensive experimental study on the effects of hysteresis on permanent capillary trapping and relative permeability of CO2/brine and supercritical (sc)CO2+SO2/brine systems. We performed numerous unsteady- and steady-state drainage and imbibition full-recirculation flow experiments in three different sandstone rock samples, i.e., low and high-permeability Berea, Nugget sandstones, and Madison limestone carbonate rock sample. A state-of-the-art reservoir conditions core-flooding system was used to perform the tests. The core-flooding apparatus included a medical CT scanner to measure in-situ saturations. The scanner was rotated to the horizontal orientation allowing flow tests through vertically-placed core samples with about 3.8 cm diameter and 15 cm length. Both scCO2 /brine and gaseous CO2 (gCO2)/brine fluid systems were studied. The gaseous and supercritical CO2/brine experiments were carried out at 3.46 and 11 MPa back pressures and 20 and 55°C temperatures, respectively. Under the above-mentioned conditions, the gCO2 and scCO2 have 0.081 and 0.393 gr/cm3 densities, respectively. During unsteady-state tests, the samples were first saturated with brine and then flooded with CO2 (drainage) at different maximum flow rates. The drainage process was then followed by a low flow rate (0.375 cm 3/min) imbibition until residual CO2 saturation was achieved. Wide flow rate ranges of 0.25 to 20 cm3/min for scCO2 and 0.125 to 120 cm3min for gCO2 were used to investigate the variation of initial brine saturation (Swi) with maximum CO2 flow rate and variation of trapped CO2 saturation (SCO2r) with Swi. For a given Swi, the trapped scCO2 saturation was less than that of gCO2 in the same sample. This was attributed to brine being less wetting in the presence of scCO2 than in the presence of gCO 2. During the steady-state experiments, after providing of fully-brine saturated core, scCO2 was injected along with brine to find the drainage curve and as

  7. CO2 deficit in temperate forest soils receiving high atmospheric N-deposition.

    Science.gov (United States)

    Fleischer, Siegfried

    2003-02-01

    Evidence is provided for an internal CO2 sink in forest soils, that may have a potential impact on the global CO2-budget. Lowered CO2 fraction in the soil atmosphere, and thus lowered CO2 release to the aboveground atmosphere, is indicated in high N-deposition areas. Also at forest edges, especially of spruce forest, where additional N-deposition has occurred, the soil CO2 is lowered, and the gradient increases into the closed forest. Over the last three decades the capacity of the forest soil to maintain the internal sink process has been limited to a cumulative supply of approximately 1000 and 1500 kg N ha(-1). Beyond this limit the internal soil CO2 sink becomes an additional CO2 source, together with nitrogen leaching. This stage of "nitrogen saturation" is still uncommon in closed forests in southern Scandinavia, however, it occurs in exposed forest edges which receive high atmospheric N-deposition. The soil CO2 gradient, which originally increases from the edge towards the closed forest, becomes reversed.

  8. High temperature CO2 capture of hydroxyapatite extracted from tilapia scales

    Directory of Open Access Journals (Sweden)

    Oscar H. Ojeda-Niño

    2017-11-01

    Full Text Available Hydroxyapatite (HAp was obtained from tilapia scales by two extraction methods: direct calcination and acid-base treatment. The physicochemical characteristics of the obtained HAps were evaluated by thermogravimetric analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, surface area, infrared spectroscopy, and basicity measurement at 298 K by CO2-pulse titration. Furthermore, the CO2 capture capacity of the solids at high temperature was also determined. Both methods showed the presence of a HAp phase although significant differences in the properties of the solids were found. The HAp obtained by direct calcination exhibited a lower crystallinity and a greater surface area and basicity than the HAp obtained by the acid-base treatment. These features were correlated with the solid’s CO2 capture capacity. In this work, CO2 capture capacity values for HAp yielded by calcination ranged from 2.5 to 3.2 mg CO2 /g captured at 973 K, and for the acid-base treatment-derived HAp, CO2 capture capacity values between 1.2 to 2.5 mg CO2 /g were recorded. These results reveal the potential of HAps extracted from tilapia scales as solids with high CO2 capture capacity, thermal stability, and capture/release cycles reversibility.

  9. Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

    Science.gov (United States)

    Wang, S.; Tokunaga, T. K.

    2014-12-01

    In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

  10. Application Of CO2 Lasers To High Speed Blanking

    Science.gov (United States)

    Grenier, L. E.

    1986-11-01

    While laser cutting of sheetmetal has attained wide acceptance in the automotive industry for the purposes of prototyping and very limited preproduction work, the production rates possible with currently available systems have precluded the use of this technique in a production environment. The device design to be described embodies a high speed X-Y positioner carrying a cutting head with limited Z-axis capability. This approach confers two main benefits, first, production rate is limited only by laser power, since the positioner technology selected will permit movement at rates up to 1.5 m/s (60 in/s), second, the use of a high speed non-contact surface follower to control the Z-axis movement reduces the need to clamp the workpiece rigidly to a precision reference surface. The realized reduction of the clamping requirement permits some latitude in the feed methods that can be employed, allowing the use of coil or sheet feeding as appropriate. The author will provide estimated production rates for the proposed design and demonstrate that a suitable choice of laser source and material feed will permit the production of parts at a rate and cost comparable to conventional blanking with the advantage of much greater flexibility and reduced retooling time.

  11. CO2 laser cutting of advanced high strength steels (AHSS)

    International Nuclear Information System (INIS)

    Lamikiz, A.; Lacalle, L.N. Lopez de; Sanchez, J.A.; Pozo, D. del; Etayo, J.M.; Lopez, J.M.

    2005-01-01

    This article demonstrates the optimum working areas and cutting conditions for the laser cutting of a series of advanced high strength steels (AHSS). The parameters that most influence the cutting of sheet metal have been studied and the results have been divided into two large groups with thickness of more and less than 1 mm. The influence of the material and, more important, the effect of coating have been taken into account. The results, have demonstrate very different behaviours between the thinnest and thickest sheets, whilst the variation of the cutting parameters due to the influence of the material is less relevant. The optimum cutting areas and the quality of the cut evaluated with different criteria are presented. Finally, the best position for the laser beam has been observed to be underneath the sheet

  12. Dual Phase Membrane for High Temperature CO2 Separation

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Lin

    2007-06-30

    This project aimed at synthesis of a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Metal-carbonate dual-phase membranes were prepared by the direct infiltration method and the synthesis conditions were optimized. Permeation tests for CO{sub 2} and N{sub 2} from 450-750 C showed very low permeances of those two gases through the dual-phase membrane, which was expected due to the lack of ionization of those two particular gases. Permeance of the CO{sub 2} and O{sub 2} mixture was much higher, indicating that the gases do form an ionic species, CO{sub 3}{sup 2-}, enhancing transport through the membrane. However, at temperatures in excess of 650 C, the permeance of CO{sub 3}{sup 2-} decreased rapidly, while predictions showed that permeance should have continued to increase with temperature. XRD data obtained from used membrane indicated that lithium iron oxides formed on the support surface. This lithium iron oxide layer has a very low conductivity, which drastically reduces the flow of electrons to the CO{sub 2}/O{sub 2} gas mixture; thus limiting the formation of the ionic species required for transport through the membrane. These results indicated that the use of stainless steel supports in a high temperature oxidative environment can lead to decreased performance of the membranes. This revelation created the need for an oxidation resistant support, which could be gained by the use of a ceramic-type membrane. Work was extended to synthesize a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Helium permeance of the support before and after infiltration of molten carbonate are on the order of 10{sup -6} and 10{sup -10} moles/m{sup 2} {center_dot} Pa {center_dot} s respectively, indicating that the molten carbonate is able to sufficiently infiltrate the membrane. It was found that La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (LSCF) was a suitable candidate for the support

  13. High efficiency nanocomposite sorbents for CO2 capture based on amine-functionalized mesoporous capsules

    KAUST Repository

    Qi, Genggeng; Wang, Yanbing; Estevez, Luis; Duan, Xiaonan; Anako, Nkechi; Park, Ah-Hyung Alissa; Li, Wen; Jones, Christopher W.; Giannelis, Emmanuel P.

    2011-01-01

    A novel high efficiency nanocomposite sorbent for CO2 capture has been developed based on oligomeric amine (polyethylenimine, PEI, and tetraethylenepentamine, TEPA) functionalized mesoporous silica capsules. The newly synthesized sorbents exhibit extraordinary capture capacity up to 7.9 mmol g-1 under simulated flue gas conditions (pre-humidified 10% CO 2). The CO2 capture kinetics were found to be fast and reached 90% of the total capacities within the first few minutes. The effects of the mesoporous capsule features such as particle size and shell thickness on CO2 capture capacity were investigated. Larger particle size, higher interior void volume and thinner mesoporous shell thickness all improved the CO2 capacity of the sorbents. PEI impregnated sorbents showed good reversibility and stability during cyclic adsorption-regeneration tests (50 cycles). © 2011 The Royal Society of Chemistry.

  14. High efficiency of CO2-activated graphite felt as electrode for vanadium redox flow battery application

    Science.gov (United States)

    Chang, Yu-Chung; Chen, Jian-Yu; Kabtamu, Daniel Manaye; Lin, Guan-Yi; Hsu, Ning-Yih; Chou, Yi-Sin; Wei, Hwa-Jou; Wang, Chen-Hao

    2017-10-01

    A simple method for preparing CO2-activated graphite felt as an electrode in a vanadium redox flow battery (VRFB) was employed by the direct treatment in a CO2 atmosphere at a high temperature for a short period. The CO2-activated graphite felt demonstrates excellent electrochemical activity and reversibility. The VRFB using the CO2-activated graphite felts in the electrodes has coulombic, voltage, and energy efficiencies of 94.52%, 88.97%, and 84.15%, respectively, which is much higher than VRFBs using the electrodes of untreated graphite felt and N2-activated graphite felt. The efficiency enhancement was attributed to the higher number of oxygen-containing functional groups on the graphite felt that are formed during the CO2-activation, leading to improving the electrochemical behaviour of the resultant VRFB.

  15. Receding and advancing (CO_2 + brine + quartz) contact angles as a function of pressure, temperature, surface roughness, salt type and salinity

    International Nuclear Information System (INIS)

    Al-Yaseri, Ahmed Z.; Lebedev, Maxim; Barifcani, Ahmed; Iglauer, Stefan

    2016-01-01

    Highlights: • (Water + CO_2) contact angle on quartz increases substantially with pressure and salinity. • (Water + CO_2) contact angle on quartz increases slightly with temperature. • Surface roughness has only a minor influence on (water + CO_2 + quartz) contact angles. - Abstract: The wetting characteristics of CO_2 in rock are of vital importance in carbon geo-storage as they determine fluid dynamics and storage capacities. However, the current literature data has a high uncertainty, which translates into uncertain predictions in terms of containment security and economic project feasibility. We thus measured contact angles for the CO_2/water/quartz system at relevant reservoir conditions, and analysed the effects of pressure (0.1 to 20) MPa, temperature (296 to 343) K, surface roughness (56 to 1300) nm, salt type (NaCl, CaCl_2, and MgCl_2) and brine salinities (0 to 35) wt%. Water contact angles decreased with surface roughness, but increased with pressure, temperature, and brine salinity. Overall the contact angles were significantly increased at storage conditions (∼50°) when compared to ambient conditions (always 0°). Consequently quartz is weakly water-wet (not completely water-wet) at storage conditions, and structural and residual trapping capacities are reduced accordingly.

  16. Heat Transfer Characteristics of CO2 at Supercritical Pressure in a Vertical Circular Tube

    International Nuclear Information System (INIS)

    Yoo, Tae Ho; Bae, Yoon Yong; Kim, Hwan Yeol

    2011-01-01

    At supercritical pressure, the physical properties of fluid change substantially and the heat transfer at a temperature similar to the critical or pseudo-critical temperature improves considerably: however, the heat transfer may deteriorate due to a sudden increase in the wall temperature at a certain condition of a mass and heat flux. In this study, the heat transfer rates in CO 2 flowing vertically upward and downward in a circular tube with a diameter of 4.57 mm under various conditions were calculated by measuring the temperature of the outer wall of the tube. The published heat transfer correlations(6,7) were analyzed by comparing their prediction values with 7,250 experimental data. By introducing a buoyancy parameter, a heat transfer correlation, which could be applied only to a normal heat transfer regime, was extended such that it can be applied to regime of heat transfer deterioration. The published criteria for heat transfer deterioration(9-12) were evaluated against the conditions obtained from the experiment in this study

  17. Pressure effect on thermopower of Y1-xGdxCo2 alloy system

    International Nuclear Information System (INIS)

    Nakama, T.; Takaesu, Y.; Uchima, K.; Yagasaki, K.; Hedo, M.; Uwatoko, Y.; Burkov, A.T.

    2007-01-01

    Thermopower of Y 1-x Gd x Co 2 pseudobinary compounds has been measured at temperatures from 1.5 to 300K under hydrostatic pressure up to 2GPa and in magnetic field 0-15T. In the inhomogeneous and paramagnetic regions of the phase diagram the main contribution to the electronic transport is related to the strong static magnetic fluctuations, which arise due to interplay of structural disorder within Gd-sublattice and Co-3d itinerant electron metamagnetism. This complex magnetic disorder brings about novel transport phenomena, such as anomalous positive magnetoresistance found in ferrimagnetic state of the alloys. The low-temperature thermopower is almost independent of alloy composition in the ferrimagnetic range of the phase diagram (x>0.3) indicating that the alloying does not change electronic structure of the compounds in a close vicinity of Fermi energy. However, the thermopower shows substantial variation with the composition in the inhomogeneous and in the paramagnetic regions of the phase diagram reflecting evolution of the magnetic structure with the composition

  18. Highly Surface-Active Ca(OH)2 Monolayer as a CO2 Capture Material.

    Science.gov (United States)

    Özçelik, V Ongun; Gong, Kai; White, Claire E

    2018-03-14

    Greenhouse gas emissions originating from fossil fuel combustion contribute significantly to global warming, and therefore the design of novel materials that efficiently capture CO 2 can play a crucial role in solving this challenge. Here, we show that reducing the dimensionality of bulk crystalline portlandite results in a stable monolayer material, named portlandene, that is highly effective at capturing CO 2 . On the basis of theoretical analysis comprised of ab initio quantum mechanical calculations and force-field molecular dynamics simulations, we show that this single-layer phase is robust and maintains its stability even at high temperatures. The chemical activity of portlandene is seen to further increase upon defect engineering of its surface using vacancy sites. Defect-containing portlandene is capable of separating CO and CO 2 from a syngas (CO/CO 2 /H 2 ) stream, yet is inert to water vapor. This selective behavior and the associated mechanisms have been elucidated by examining the electronic structure, local charge distribution, and bonding orbitals of portlandene. Additionally, unlike conventional CO 2 capturing technologies, the regeneration process of portlandene does not require high temperature heat treatment because it can release the captured CO 2 by application of a mild external electric field, making portlandene an ideal CO 2 capturing material for both pre- and postcombustion processes.

  19. Ultrathin Composite Polymeric Membranes for CO2 /N2 Separation with Minimum Thickness and High CO2 Permeance.

    Science.gov (United States)

    Benito, Javier; Sánchez-Laínez, Javier; Zornoza, Beatriz; Martín, Santiago; Carta, Mariolino; Malpass-Evans, Richard; Téllez, Carlos; McKeown, Neil B; Coronas, Joaquín; Gascón, Ignacio

    2017-10-23

    The use of ultrathin films as selective layers in composite membranes offers significant advantages in gas separation for increasing productivity while reducing the membrane size and energy costs. In this contribution, composite membranes have been obtained by the successive deposition of approximately 1 nm thick monolayers of a polymer of intrinsic microporosity (PIM) on top of dense membranes of the ultra-permeable poly[1-(trimethylsilyl)-1-propyne] (PTMSP). The ultrathin PIM films (30 nm in thickness) demonstrate CO 2 permeance up to seven times higher than dense PIM membranes using only 0.04 % of the mass of PIM without a significant decrease in CO 2 /N 2 selectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Global high-resolution monthly pCO2 climatology for the coastal ocean derived from neural network interpolation

    Directory of Open Access Journals (Sweden)

    G. G. Laruelle

    2017-10-01

    Full Text Available In spite of the recent strong increase in the number of measurements of the partial pressure of CO2 in the surface ocean (pCO2, the air–sea CO2 balance of the continental shelf seas remains poorly quantified. This is a consequence of these regions remaining strongly under-sampled in both time and space and of surface pCO2 exhibiting much higher temporal and spatial variability in these regions compared to the open ocean. Here, we use a modified version of a two-step artificial neural network method (SOM-FFN; Landschützer et al., 2013 to interpolate the pCO2 data along the continental margins with a spatial resolution of 0.25° and with monthly resolution from 1998 to 2015. The most important modifications compared to the original SOM-FFN method are (i the much higher spatial resolution and (ii the inclusion of sea ice and wind speed as predictors of pCO2. The SOM-FFN is first trained with pCO2 measurements extracted from the SOCATv4 database. Then, the validity of our interpolation, in both space and time, is assessed by comparing the generated pCO2 field with independent data extracted from the LDVEO2015 database. The new coastal pCO2 product confirms a previously suggested general meridional trend of the annual mean pCO2 in all the continental shelves with high values in the tropics and dropping to values beneath those of the atmosphere at higher latitudes. The monthly resolution of our data product permits us to reveal significant differences in the seasonality of pCO2 across the ocean basins. The shelves of the western and northern Pacific, as well as the shelves in the temperate northern Atlantic, display particularly pronounced seasonal variations in pCO2,  while the shelves in the southeastern Atlantic and in the southern Pacific reveal a much smaller seasonality. The calculation of temperature normalized pCO2 for several latitudes in different oceanic basins confirms that the seasonality in shelf pCO2 cannot solely be explained by

  1. Coral energy reserves and calcification in a high-CO2 world at two temperatures.

    Directory of Open Access Journals (Sweden)

    Verena Schoepf

    Full Text Available Rising atmospheric CO2 concentrations threaten coral reefs globally by causing ocean acidification (OA and warming. Yet, the combined effects of elevated pCO2 and temperature on coral physiology and resilience remain poorly understood. While coral calcification and energy reserves are important health indicators, no studies to date have measured energy reserve pools (i.e., lipid, protein, and carbohydrate together with calcification under OA conditions under different temperature scenarios. Four coral species, Acropora millepora, Montipora monasteriata, Pocillopora damicornis, Turbinaria reniformis, were reared under a total of six conditions for 3.5 weeks, representing three pCO2 levels (382, 607, 741 µatm, and two temperature regimes (26.5, 29.0 °C within each pCO2 level. After one month under experimental conditions, only A. millepora decreased calcification (-53% in response to seawater pCO2 expected by the end of this century, whereas the other three species maintained calcification rates even when both pCO2 and temperature were elevated. Coral energy reserves showed mixed responses to elevated pCO2 and temperature, and were either unaffected or displayed nonlinear responses with both the lowest and highest concentrations often observed at the mid-pCO2 level of 607 µatm. Biweekly feeding may have helped corals maintain calcification rates and energy reserves under these conditions. Temperature often modulated the response of many aspects of coral physiology to OA, and both mitigated and worsened pCO2 effects. This demonstrates for the first time that coral energy reserves are generally not metabolized to sustain calcification under OA, which has important implications for coral health and bleaching resilience in a high-CO2 world. Overall, these findings suggest that some corals could be more resistant to simultaneously warming and acidifying oceans than previously expected.

  2. Highly Efficient Closed-Loop CO2 Removal System for Deep-Space ECLSS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — TDA Research Inc.(TDA) in collaboration with University of Puerto Rico ? Mayaguez (UPRM is proposing to develop a highly efficient CO2 removal system based on UPRM...

  3. Analysis of Pacific oyster larval proteome and its response to high-CO2

    KAUST Repository

    Dineshram, R.; Wong, Kelvin K.W.; Xiao, Shu; Yu, Ziniu; Qian, Pei Yuan; Thiyagarajan, Vengatesen

    2012-01-01

    Most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-CO2 due to ocean acidification (OA) process. Analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool

  4. Painted Goby Larvae under High-CO2 Fail to Recognize Reef Sounds.

    Directory of Open Access Journals (Sweden)

    Joana M Castro

    Full Text Available Atmospheric CO2 levels have been increasing at an unprecedented rate due to anthropogenic activity. Consequently, ocean pCO2 is increasing and pH decreasing, affecting marine life, including fish. For many coastal marine fishes, selection of the adult habitat occurs at the end of the pelagic larval phase. Fish larvae use a range of sensory cues, including sound, for locating settlement habitat. This study tested the effect of elevated CO2 on the ability of settlement-stage temperate fish to use auditory cues from adult coastal reef habitats. Wild late larval stages of painted goby (Pomatoschistus pictus were exposed to control pCO2 (532 μatm, pH 8.06 and high pCO2 (1503 μatm, pH 7.66 conditions, likely to occur in nearshore regions subjected to upwelling events by the end of the century, and tested in an auditory choice chamber for their preference or avoidance to nighttime reef recordings. Fish reared in control pCO2 conditions discriminated reef soundscapes and were attracted by reef recordings. This behaviour changed in fish reared in the high CO2 conditions, with settlement-stage larvae strongly avoiding reef recordings. This study provides evidence that ocean acidification might affect the auditory responses of larval stages of temperate reef fish species, with potentially significant impacts on their survival.

  5. High spin-polarization in ultrathin Co2MnSi/CoPd multilayers

    Science.gov (United States)

    Galanakis, I.

    2015-03-01

    Half-metallic Co2MnSi finds a broad spectrum of applications in spintronic devices either in the form of thin films or as spacer in multilayers. Using state-of-the-art ab-initio electronic structure calculations we exploit the electronic and magnetic properties of ultrathin Co2MnSi/CoPd multilayers. We show that these heterostructures combine high values of spin-polarization at the Co2MnSi spacer with the perpendicular magnetic anisotropy of binary compounds such as CoPd. Thus they could find application in spintronic/magnetoelectronic devices.

  6. Oysters and eelgrass: potential partners in a high pCO2 ocean.

    Science.gov (United States)

    Groner, Maya L; Burge, Colleen A; Cox, Ruth; Rivlin, Natalie; Turner, Mo; Van Alstyne, Kathryn L; Wyllie-Echeverria, Sandy; Bucci, John; Staudigel, Philip; Friedman, Carolyn S

    2018-05-25

    Climate change is affecting the health and physiology of marine organisms and altering species interactions. Ocean acidification (OA) threatens calcifying organisms such as the Pacific oyster, Crassostrea gigas. In contrast, seagrasses, such as the eelgrass Zostera marina, can benefit from the increase in available carbon for photosynthesis found at a lower seawater pH. Seagrasses can remove dissolved inorganic carbon from OA environments, creating local daytime pH refugia. Pacific oysters may improve the health of eelgrass by filtering out pathogens such as Labyrinthula zosterae (LZ), which causes eelgrass wasting disease (EWD). We examined how co-culture of eelgrass ramets and juvenile oysters affected the health and growth of eelgrass and the mass of oysters under different pCO 2 exposures. In Phase I, each species was cultured alone or in co-culture at 12°C across ambient, medium, and high pCO 2 conditions, (656, 1158 and1606 μatm pCO 2 , respectively). Under high pCO 2 , eelgrass grew faster and had less severe EWD (contracted in the field prior to the experiment). Co-culture with oysters also reduced the severity of EWD. While the presence of eelgrass decreased daytime pCO 2 , this reduction was not substantial enough to ameliorate the negative impact of high pCO 2 on oyster mass. In Phase II, eelgrass alone or oysters and eelgrass in co-culture were held at 15°C under ambient and high pCO 2 conditions, (488 and 2013 μatm pCO 2 , respectively). Half of the replicates were challenged with cultured LZ. Concentrations of defensive compounds in eelgrass (total phenolics and tannins), were altered by LZ exposure and pCO 2 treatments. Greater pathogen loads and increased EWD severity were detected in LZ exposed eelgrass ramets; EWD severity was reduced at high relative to low pCO 2 . Oyster presence did not influence pathogen load or EWD severity; high LZ concentrations in experimental treatments may have masked the effect of this treatment. Collectively, these

  7. Effects of long-term high CO2 exposure on two species of coccolithophores

    Directory of Open Access Journals (Sweden)

    K. G. Schulz

    2010-03-01

    Full Text Available The physiological performance of two coccolithophore species, Emiliania huxleyi and Coccolithus braarudii, was investigated during long-term exposure to elevated pCO2 levels. Mono-specific cultures were grown over 152 (E. huxleyi and 65 (C. braarudii generations while pCO2 was gradually increased to maximum levels of 1150 μatm (E. huxleyi and 930 μatm (C. braarudii and kept constant thereafter. Rates of cell growth and cell quotas of particulate organic carbon (POC, particulate inorganic carbon (PIC and total particulate nitrogen (TPN were determined repeatedly throughout the incubation period. Increasing pCO2 caused a decrease in cell growth rate of 9% and 29% in E. huxleyi and C. braarudii, respectively. In both species cellular PIC:TPN and PIC:POC ratios decreased in response to rising pCO2, whereas no change was observed in the POC:TPN ratios of E. huxleyi and C. braarudii. These results are consistent with those obtained in shorter-term high CO2 exposure experiments following abrupt pertubations of the seawater carbonate system and indicate that for the strains tested here a gradual CO2 increase does not alleviate CO2/pH sensitivity.

  8. Highly CO2-supersaturated melts in the Pannonian lithospheric mantle - A transient carbon reservoir?

    Science.gov (United States)

    Créon, Laura; Rouchon, Virgile; Youssef, Souhail; Rosenberg, Elisabeth; Delpech, Guillaume; Szabó, Csaba; Remusat, Laurent; Mostefaoui, Smail; Asimow, Paul D.; Antoshechkina, Paula M.; Ghiorso, Mark S.; Boller, Elodie; Guyot, François

    2017-08-01

    Subduction of carbonated crust is widely believed to generate a flux of carbon into the base of the continental lithospheric mantle, which in turn is the likely source of widespread volcanic and non-volcanic CO2 degassing in active tectonic intracontinental settings such as rifts, continental margin arcs and back-arc domains. However, the magnitude of the carbon flux through the lithosphere and the budget of stored carbon held within the lithospheric reservoir are both poorly known. We provide new constraints on the CO2 budget of the lithospheric mantle below the Pannonian Basin (Central Europe) through the study of a suite of xenoliths from the Bakony-Balaton Highland Volcanic Field. Trails of secondary fluid inclusions, silicate melt inclusions, networks of melt veins, and melt pockets with large and abundant vesicles provide numerous lines of evidence that mantle metasomatism affected the lithosphere beneath this region. We obtain a quantitative estimate of the CO2 budget of the mantle below the Pannonian Basin using a combination of innovative analytical and modeling approaches: (1) synchrotron X-ray microtomography, (2) NanoSIMS, Raman spectroscopy and microthermometry, and (3) thermodynamic models (Rhyolite-MELTS). The three-dimensional volumes reconstructed from synchrotron X-ray microtomography allow us to quantify the proportions of all petrographic phases in the samples and to visualize their textural relationships. The concentration of CO2 in glass veins and pockets ranges from 0.27 to 0.96 wt.%, higher than in typical arc magmas (0-0.25 wt.% CO2), whereas the H2O concentration ranges from 0.54 to 4.25 wt.%, on the low end for estimated primitive arc magmas (1.9-6.3 wt.% H2O). Trapping pressures for vesicles were determined by comparing CO2 concentrations in glass to CO2 saturation as a function of pressure in silicate melts, suggesting pressures between 0.69 to 1.78 GPa. These values are generally higher than trapping pressures for fluid inclusions

  9. Monitoring of injected CO2 at two commercial geologic storage sites with significant pressure depletion and/or re-pressurization histories: A case study

    Directory of Open Access Journals (Sweden)

    Dayanand Saini

    2017-03-01

    The monitoring technologies that have been used/deployed/tested at both the normally pressured West Hastings and the subnormally pressured Bell Creek storage sites appear to adequately address any of the potential “out of zone migration” of injected CO2 at these sites. It would be interesting to see if any of the collected monitoring data at the West Hastings and the Bell Creek storage sites could also be used in future to better understand the viability of initially subnormally pressured and subsequently depleted and re-pressurized oil fields as secure geologic CO2 storage sites with relatively large storage CO2 capacities compared to the depleted and re-pressurized oil fields that were initially discovered as normally pressured.

  10. Assessment of Dynamic Flow, Pressure and Geomechanical Behaviour of a CO2 Storage Complex

    DEFF Research Database (Denmark)

    Mbia, Ernest Ncha; Frykman, Peter

    dioxide (CO2) is the primary greenhouse gas emitted through human activities. Over 7,500 large CO2 emission sources (above 0.1 million tons CO2 year-1) have been identified (IPCC, 2005). These sources are distributed geographically around the world but four clusters of emissions can be observed: in North......-fired power plants) and injecting it into deep formations (e.g., saline aquifers, oil and gas reservoirs, and coalbeds) for storage. This process has drawn increasing consideration as a promising mitigation method that is economically possible. Deep saline aquifers offer the largest storage potential of all...

  11. Thermodynamic properties of CO2 absorption in hydroxyl ammonium ionic liquids at pressures of (100-1600) kPa

    International Nuclear Information System (INIS)

    Kurnia, K.A.; Harris, F.; Wilfred, C.D.; Abdul Mutalib, M.I.; Murugesan, T.

    2009-01-01

    Solubility of CO 2 in six hydroxyl ammonium ionic liquids 2-hydroxyethanaminium acetate [hea], bis(2-hydroxyethyl)ammonium acetate [bheaa], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate [hhemea], 2-hydroxyethanaminium lactate [hel], bis(2-hydroxyethyl)ammonium lactate [bheal], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium lactate [hhemel] at temperatures (298.15, 313.15, and 328.16) K and pressures ranging from (100 to 1600) kPa was determined. From the experimental solubility data, the Henry's constant of CO 2 for each hydroxyl ammonium ionic liquids was estimated and reported as a function of temperature. Furthermore, enthalpy and entropy of absorption were obtained from estimated Henry's constant. The results showed that the solubility increase with increasing pressure and decrease with increasing temperature and the solubility of CO 2 in these six hydroxyl ammonium ionic liquids was in sequence: [hea] > [bheaa] > [hel] > [bheal] > [hhemel] > [hhemea].

  12. Skeletal mineralogy of coral recruits under high temperature and pCO2

    Directory of Open Access Journals (Sweden)

    T. Foster

    2016-03-01

    Our results show that elevated pCO2 alone is unlikely to drive changes in the skeletal mineralogy of young corals. Not having an ability to switch from aragonite to calcite precipitation may leave corals and ultimately coral reef ecosystems more susceptible to predicted ocean acidification. An important area for prospective research would be the investigation of the combined impact of high pCO2 and reduced Mg ∕ Ca ratio on coral skeletal mineralogy.

  13. Facile synthesis of hybrid CNTs/NiCo2S4 composite for high performance supercapacitors

    Science.gov (United States)

    Li, Delong; Gong, Youning; Pan, Chunxu

    2016-07-01

    In this work, a novel carbon nanotubes (CNTs)/NiCo2S4 composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo2S4 composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo2S4 hexagonal nanoplates. Compared with pure NiCo2S4 and the mechanically mixed CNTs/NiCo2S4 composite, the CNTs/NiCo2S4 composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.

  14. Facile synthesis of hybrid CNTs/NiCo2S4 composite for high performance supercapacitors.

    Science.gov (United States)

    Li, Delong; Gong, Youning; Pan, Chunxu

    2016-07-11

    In this work, a novel carbon nanotubes (CNTs)/NiCo2S4 composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo2S4 composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo2S4 hexagonal nanoplates. Compared with pure NiCo2S4 and the mechanically mixed CNTs/NiCo2S4 composite, the CNTs/NiCo2S4 composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.

  15. Advective transport of CO2 in permeable media induced by atmospheric pressure fluctuations: 2. Observational evidence under snowpacks

    Science.gov (United States)

    W. J. Massman; J. M. Frank

    2006-01-01

    Meadow and forest CO2 amounts sampled beneath an approximately meter deep (steady state) snowpack at a subalpine site in southern Rocky Mountains of Wyoming are observed to vary by nearly 200 ppm over periods ranging from 4 to 15 days. This work employs the model of periodic, pressure-induced, advective transport in permeable media developed in...

  16. High spin-polarization in ultrathin Co2MnSi/CoPd multilayers

    International Nuclear Information System (INIS)

    Galanakis, I.

    2015-01-01

    Half-metallic Co 2 MnSi finds a broad spectrum of applications in spintronic devices either in the form of thin films or as spacer in multilayers. Using state-of-the-art ab-initio electronic structure calculations we exploit the electronic and magnetic properties of ultrathin Co 2 MnSi/CoPd multilayers. We show that these heterostructures combine high values of spin-polarization at the Co 2 MnSi spacer with the perpendicular magnetic anisotropy of binary compounds such as CoPd. Thus they could find application in spintronic/magnetoelectronic devices. - Highlights: • Ab-initio study of ultrathin Co 2 MnSi/CoPd multilayers. • Large values of spin-polarization at the Fermi are retained. • Route for novel spintronic/magnetoelectronic devices

  17. Pressurization Risk Assessment of CO2 Reservoirs Utilizing Design of Experiments and Response Surface Methods

    Science.gov (United States)

    Guyant, E.; Han, W. S.; Kim, K. Y.; Park, E.; Han, K.

    2015-12-01

    Monitoring of pressure buildup can provide explicit information on reservoir integrity and is an appealing tool, however pressure variation is dependent on a variety of factors causing high uncertainty in pressure predictions. This work evaluated pressurization of a reservoir system in the presence of leakage pathways as well as exploring the effects of compartmentalization of the reservoir utilizing design of experiments (Definitive Screening, Box Behnken, Central Composite, and Latin Hypercube designs) and response surface methods. Two models were developed, 1) an idealized injection scenario in order to evaluate the performance of multiple designs, and 2) a complex injection scenario implementing the best performing design to investigate pressurization of the reservoir system. A holistic evaluation of scenario 1, determined that the Central Composite design would be used for the complex injection scenario. The complex scenario evaluated 5 risk factors: reservoir, seal, leakage pathway and fault permeabilities, and horizontal position of the pathway. A total of 60 response surface models (RSM) were developed for the complex scenario with an average R2 of 0.95 and a NRMSE of 0.067. Sensitivity to the input factors was dynamic through space and time; at the earliest time (0.05 years) the reservoir permeability was dominant, and for later times (>0.5 years) the fault permeability became dominant for all locations. The RSM's were then used to conduct a Monte Carlo Analysis to further analyze pressurization risks, identifying the P10, P50, P90 values. This identified the in zone (lower) P90 values as 2.16, 1.77, and 1.53 MPa and above zone values of 1.35, 1.23, 1.09 MPa for monitoring locations 1, 2, and 3, respectively. In summary, the design of experiments and response surface methods allowed for an efficient sensitivity and uncertainty analysis to be conducted permitting a complete evaluation of the pressurization across the entire parameter space.

  18. Performance evaluation of high-sulphur coal-fired USC plant integrated with SNOX and CO2 capture sections

    International Nuclear Information System (INIS)

    Cau, Giorgio; Tola, Vittorio; Bassano, Claudia

    2015-01-01

    In recent years coal-fired power plants have increased their role in the global energy scenario thanks to reliability, security of fuel supply and lower cost of fuel and electricity. In this framework global warming issues require a sustainable use of coal and great efforts for greenhouse gases reduction, addressing research and development projects towards more efficient solutions in terms of efficiency and environmental impact. With this aim in this paper a performance assessment of an Ultra Super Critical (USC) steam plant integrated with a CO 2 removal section was carried out. The study is based on simulation models specifically developed through Aspen-Plus and Gate-Cycle software platforms. Performance was assessed referring to typical USC commercial size plants (400–600 MW), fuelled by a mix of a low-sulphur coal and a Sardinian (Sulcis) high-sulphur coal. The USC plant, based on a reheated and regenerative Rankine cycle, is integrated with an SNOX section, with integrated DeNO x and DeSO x processes, and a low temperature CO 2 capture section. The SNOX technology shows several advantages in comparison to conventional de-nitrification and de-sulphuration systems. In particular it is capable to remove both nitrogen and sulphur oxides, requiring less energy absorption compared to traditional FGD systems, allowing a further preheating of the combustion air and without producing process waste. Besides the SNOX releases a commercial product as the sulphuric acid (H 2 SO 4 ) and operational costs are reduced when sulphur content in the coal increases. The CO 2 capture system was based on a chemical absorption process. A conventional system based on an amine (monoethanolamine, MEA) aqueous solution was considered. In order to match high pressure and purity CO 2 transportation requirements, the CO 2 removal section is also integrated with a conditioning and compression section. A performance assessment of the USC plant was carried out varying the high-sulphur coal

  19. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 - O2 environment

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-06-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al2O3 and TiO2) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO2, 10% O2 and 75% N2. This research investigates the effects of CO2 and O2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings.

  20. Controlling mechanisms of surface partial pressure of CO2 in Jiaozhou Bay during summer and the influence of heavy rain

    Science.gov (United States)

    Li, Yunxiao; Yang, Xufeng; Han, Ping; Xue, Liang; Zhang, Longjun

    2017-09-01

    Due to the combined effects of natural processes and human activities, carbon source/sink processes and mechanisms in the coastal ocean are becoming more and more important in current ocean carbon cycle research. Based on differences in the ratio of total alkalinity (TA) to dissolved inorganic carbon (DIC) associated with terrestrial input, biological process (production and respiration), calcium carbonate (CaCO3) process (precipitation and dissolution) and CO2 evasion/invasion, we discuss the mechanisms controlling the surface partial pressure of CO2 (pCO2) in Jiaozhou Bay (JZB) during summer and the influence of heavy rain, via three cruises performed in mid-June, early July and late July of 2014. In mid-June and in early July, without heavy rain or obvious river input, sea surface pCO2 ranged from 521 to 1080 μatm and from 547 to 998 μatm, respectively. The direct input of DIC from sewage and the intense respiration produced large DIC additions and the highest pCO2 values in the northeast of the bay near the downtown of Qingdao. However, in the west of the bay, significant CaCO3 precipitation led to DIC removal but no obvious increase in pCO2, which was just close to that in the central area. Due to the shallow depth and longer water residence time in this region, this pattern may be related to the sustained release of CO2 into the atmosphere. In late July, heavy rain promoted river input in the western and eastern portions of JZB. Strong primary production led to a significant decrease in pCO2 in the western area, with the lowest pCO2 value of 252 μatm. However, in the northeastern area, the intense respiration remained, and the highest pCO2 value was 1149 μatm. The average air-sea CO2 flux in mid-June and early July was 20.23 mmol m- 2 d- 1 and 23.56 mmol m- 2 d- 1, respectively. In contrast, in late July, sources became sinks for atmospheric CO2 in the western and central areas of the bay, halving the average air-sea CO2 flux to a value of 10.58 mmol m- 2

  1. Acclimation to high CO2 in maize is related to water status and dependent on leaf rank.

    Science.gov (United States)

    Prins, Anneke; Mukubi, Josephine Muchwesi; Pellny, Till K; Verrier, Paul J; Beyene, Getu; Lopes, Marta Silva; Emami, Kaveh; Treumann, Achim; Lelarge-Trouverie, Caroline; Noctor, Graham; Kunert, Karl J; Kerchev, Pavel; Foyer, Christine H

    2011-02-01

    The responses of C(3) plants to rising atmospheric CO(2) levels are considered to be largely dependent on effects exerted through altered photosynthesis. In contrast, the nature of the responses of C(4) plants to high CO(2) remains controversial because of the absence of CO(2) -dependent effects on photosynthesis. In this study, the effects of atmospheric CO(2) availability on the transcriptome, proteome and metabolome profiles of two ranks of source leaves in maize (Zea mays L.) were studied in plants grown under ambient CO(2) conditions (350 +/- 20 µL L(-1) CO(2) ) or with CO(2) enrichment (700 +/- 20 µL L(-1) CO(2) ). Growth at high CO(2) had no effect on photosynthesis, photorespiration, leaf C/N ratios or anthocyanin contents. However, leaf transpiration rates, carbohydrate metabolism and protein carbonyl accumulation were altered at high CO(2) in a leaf-rank specific manner. Although no significant CO(2) -dependent changes in the leaf transcriptome were observed, qPCR analysis revealed that the abundance of transcripts encoding a Bowman-Birk protease inhibitor and a serpin were changed by the growth CO(2) level in a leaf rank specific manner. Moreover, CO(2) -dependent changes in the leaf proteome were most evident in the oldest source leaves. Small changes in water status may be responsible for the observed responses to high CO(2,) particularly in the older leaf ranks. © 2010 Blackwell Publishing Ltd.

  2. An advanced analytical solution for pressure build-up during CO2 injection into infinite saline aquifers: The role of compressibility

    Science.gov (United States)

    Wu, Haiqing; Bai, Bing; Li, Xiaochun

    2018-02-01

    Existing analytical or approximate solutions that are appropriate for describing the migration mechanics of CO2 and the evolution of fluid pressure in reservoirs do not consider the high compressibility of CO2, which reduces their calculation accuracy and application value. Therefore, this work first derives a new governing equation that represents the movement of complex fluids in reservoirs, based on the equation of continuity and the generalized Darcy's law. A more rigorous definition of the coefficient of compressibility of fluid is then presented, and a power function model (PFM) that characterizes the relationship between the physical properties of CO2 and the pressure is derived. Meanwhile, to avoid the difficulty of determining the saturation of fluids, a method that directly assumes the average relative permeability of each fluid phase in different fluid domains is proposed, based on the theory of gradual change. An advanced analytical solution is obtained that includes both the partial miscibility and the compressibility of CO2 and brine in evaluating the evolution of fluid pressure by integrating within different regions. Finally, two typical sample analyses are used to verify the reliability, improved nature and universality of this new analytical solution. Based on the physical characteristics and the results calculated for the examples, this work elaborates the concept and basis of partitioning for use in further work.

  3. A new set-up for simultaneous high-precision measurements of CO2, δ13C-CO2 and δ18O-CO2 on small ice core samples

    Science.gov (United States)

    Jenk, Theo Manuel; Rubino, Mauro; Etheridge, David; Ciobanu, Viorela Gabriela; Blunier, Thomas

    2016-08-01

    Palaeoatmospheric records of carbon dioxide and its stable carbon isotope composition (δ13C) obtained from polar ice cores provide important constraints on the natural variability of the carbon cycle. However, the measurements are both analytically challenging and time-consuming; thus only data exist from a limited number of sampling sites and time periods. Additional analytical resources with high analytical precision and throughput are thus desirable to extend the existing datasets. Moreover, consistent measurements derived by independent laboratories and a variety of analytical systems help to further increase confidence in the global CO2 palaeo-reconstructions. Here, we describe our new set-up for simultaneous measurements of atmospheric CO2 mixing ratios and atmospheric δ13C and δ18O-CO2 in air extracted from ice core samples. The centrepiece of the system is a newly designed needle cracker for the mechanical release of air entrapped in ice core samples of 8-13 g operated at -45 °C. The small sample size allows for high resolution and replicate sampling schemes. In our method, CO2 is cryogenically and chromatographically separated from the bulk air and its isotopic composition subsequently determined by continuous flow isotope ratio mass spectrometry (IRMS). In combination with thermal conductivity measurement of the bulk air, the CO2 mixing ratio is calculated. The analytical precision determined from standard air sample measurements over ice is ±1.9 ppm for CO2 and ±0.09 ‰ for δ13C. In a laboratory intercomparison study with CSIRO (Aspendale, Australia), good agreement between CO2 and δ13C results is found for Law Dome ice core samples. Replicate analysis of these samples resulted in a pooled standard deviation of 2.0 ppm for CO2 and 0.11 ‰ for δ13C. These numbers are good, though they are rather conservative estimates of the overall analytical precision achieved for single ice sample measurements. Facilitated by the small sample requirement

  4. Fabrication and thermoelectric properties of highly textured NaCo2O4 ceramic

    International Nuclear Information System (INIS)

    Cheng Jinguang; Sui Yu; Fu Haijin; Lu Zhe; Wei Bo; Qian Zhengnan; Miao Jipeng; Liu Zhiguo; Huang Xiqiang; Zhu Ruibin; Wang Xianjie; Su Wenhui

    2006-01-01

    Highly textured NaCo 2 O 4 polycrystalline sample was fabricated by means of the cold high-pressure compacting followed by the solid-state reaction. X-ray diffraction and scanning electron microscope were employed to show that the plate-like grains within the sample are aligned along the pressing direction. The resistivity ρ and thermoelectric power S along the preferred {0 0 1} plane were measured in the whole temperature range from 15 to 973 K in air and the correlation between thermoelectric properties and texture was investigated. It was found that both ρ and S exhibit metallic behavior in the whole temperature range and the above sample exhibits lower ρ and higher S due to high texture and density. The power factor exhibits a steep rise above 400 K and reaches 761 μW m -1 K -2 at 973 K, suggesting a promising candidate for thermoelectric application at higher temperature. The change of slope in both resistivity and thermoelectric power curves at about 450 K might arise from the spin-state transition of Co ions in the CoO 2 blocks

  5. High speed surface cleaning by a high repetition rated TEA-CO2 laser

    International Nuclear Information System (INIS)

    Tsunemi, Akira; Hirai, Ryo; Hagiwara, Kouji; Nagasaka, Keigo; Tashiro, Hideo

    1994-01-01

    We demonstrated the feasibility of high speed cleaning of solid surfaces by the laser ablation technique using a TEA-CO 2 laser. The laser pulses with the repetition rate of 1 kHz were applied to paint, rust, moss and dirt attached on the surfaces. The attachments were effectively removed without the damage of bulk surfaces by the irradiation of line-focused sequential pulses with an energy of 300 mJ/pulse. A cleaning rate reached to 17 m 2 /hour for the case of paint removal from iron surfaces. (author)

  6. Reversible hydrogen storage using CO2 and a proton-switchable iridium catalyst in aqueous media under mild temperatures and pressures.

    Science.gov (United States)

    Hull, Jonathan F; Himeda, Yuichiro; Wang, Wan-Hui; Hashiguchi, Brian; Periana, Roy; Szalda, David J; Muckerman, James T; Fujita, Etsuko

    2012-03-18

    Green plants convert CO(2) to sugar for energy storage via photosynthesis. We report a novel catalyst that uses CO(2) and hydrogen to store energy in formic acid. Using a homogeneous iridium catalyst with a proton-responsive ligand, we show the first reversible and recyclable hydrogen storage system that operates under mild conditions using CO(2), formate and formic acid. This system is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption. The extraordinary and switchable catalytic activity is attributed to the multifunctional ligand, which acts as a proton-relay and strong π-donor, and is rationalized by theoretical and experimental studies.

  7. "EFFECTIVENESS OF ABDOMINAL WALL ELEVATOR IN REDUCING INTRA-ABDOMINAL PRESSURE AND CO2 VOLUME DURING LAPAROSCOPIC CHOLECYSTECTOMY"

    Directory of Open Access Journals (Sweden)

    A. Yaghoobi Notash

    2004-06-01

    Full Text Available Since CO2 pneumoperitoneum is the dominant method of laparoscopic exposure due to facility and good view, its physiologic effects are most relevant to the surgeons. CO2 pneumoperitoneum may affects hemodynamics by increased intra-abdominal pressure (IAP and the physiologic effects of absorbed CO2. The adverse effects of both mechanisms relate directly to the duration of the pneumoperitoneum and the elevation of IAP. Gasless laparoscopy involves obtaining exposure for laparoscopy by placing an internal retracting device through a small incision and lifting the anterior abdominal wall. We designed and made a mechanical wall elevator and used it in 24 patients, compared with a control group (52 cases using a conventional laparoscopic cholecystectomy. A prospective trial was undertaken in Sina Hospital, Tehran University of Medical Sciences from 1998 to 2000. The patients were assigned randomly to two groups. There was a significant decrease in IAP and CO2 consumption in the group using mechanical wall elevator as compared to conventional laparoscopic cholecystectomy, (mean IAP of 3.5 mmHg compared to 11.4 mmHg in the control group, mean CO2 volume 17 liters compared to 73 liters in the control group. We recommend this semigasless method in laparoscopy due to safety in performance and significant reduction in IAP through the surgery. This method provides a satisfactory view and easy performance without any increase in time or complications. The hospital stay and costs did not increase.

  8. High-Throughput Molecular Simulations of Metal Organic Frameworks for CO2 Separation: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Ilknur Erucar

    2018-02-01

    Full Text Available Metal organic frameworks (MOFs have emerged as great alternatives to traditional nanoporous materials for CO2 separation applications. MOFs are porous materials that are formed by self-assembly of transition metals and organic ligands. The most important advantage of MOFs over well-known porous materials is the possibility to generate multiple materials with varying structural properties and chemical functionalities by changing the combination of metal centers and organic linkers during the synthesis. This leads to a large diversity of materials with various pore sizes and shapes that can be efficiently used for CO2 separations. Since the number of synthesized MOFs has already reached to several thousand, experimental investigation of each MOF at the lab-scale is not practical. High-throughput computational screening of MOFs is a great opportunity to identify the best materials for CO2 separation and to gain molecular-level insights into the structure–performance relationships. This type of knowledge can be used to design new materials with the desired structural features that can lead to extraordinarily high CO2 selectivities. In this mini-review, we focused on developments in high-throughput molecular simulations of MOFs for CO2 separations. After reviewing the current studies on this topic, we discussed the opportunities and challenges in the field and addressed the potential future developments.

  9. High-throughput Molecular Simulations of MOFs for CO2 Separation: Opportunities and Challenges

    Science.gov (United States)

    Erucar, Ilknur; Keskin, Seda

    2018-02-01

    Metal organic frameworks (MOFs) have emerged as great alternatives to traditional nanoporous materials for CO2 separation applications. MOFs are porous materials that are formed by self-assembly of transition metals and organic ligands. The most important advantage of MOFs over well-known porous materials is the possibility to generate multiple materials with varying structural properties and chemical functionalities by changing the combination of metal centers and organic linkers during the synthesis. This leads to a large diversity of materials with various pore sizes and shapes that can be efficiently used for CO2 separations. Since the number of synthesized MOFs has already reached to several thousand, experimental investigation of each MOF at the lab-scale is not practical. High-throughput computational screening of MOFs is a great opportunity to identify the best materials for CO2 separation and to gain molecular-level insights into the structure-performance relationships. This type of knowledge can be used to design new materials with the desired structural features that can lead to extraordinarily high CO2 selectivities. In this mini-review, we focused on developments in high-throughput molecular simulations of MOFs for CO2 separations. After reviewing the current studies on this topic, we discussed the opportunities and challenges in the field and addressed the potential future developments.

  10. Efficient MgO-based mesoporous CO2 trapper and its performance at high temperature.

    Science.gov (United States)

    Han, Kun Kun; Zhou, Yu; Chun, Yuan; Zhu, Jian Hua

    2012-02-15

    A novel MgO-based porous adsorbent has been synthesized in a facile co-precipitation method for the first time, in order to provide a candidate for trapping CO(2) in flue gas at high temperature. The resulting composite exhibits a mesoporous structure with a wide pore size distribution, due to the even dispersion and distribution of microcrystalline MgO in the framework of alumina to form a concrete-like structure. These sorbents can capture CO(2) at high temperature (150-400°C), possessing high reactivity and stability in cyclic adsorption-desorption processes, providing competitive candidates to control CO(2) emission. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Explosive vaporization induced by high-power CO2-laser target interactions

    International Nuclear Information System (INIS)

    Hugenschmidt, M.; Vollrath, K.

    1976-01-01

    The interactions of high-power laser pulses with targets such as metals or dielectric materials causes a series of optical, thermal, and mechanical processes. Thereby, heating, melting, and vaporization can take place in a short time. At power densities of about 10 7 to several 10 8 W/cm 2 this can even be produced explosively. As compared to continuous ablation, this type of interaction can remove greater masses from the bulk of material. The investigations are performed by using an electron-beam preionized CO 2 -laser acting on different target materials. The energy of the laser pulses is about 30 J, the pulse-half-widths of the long-tail pulses 4 to 6 μs. Optical measurements yield some information on threshold values for these processes, for the formation and expansion of plasmas, and for the ejection of material in form of greater particles. High speed photographic techniques include a rotating mirror- and an image converter camera. Starting from shock-wave theory, gas dynamic equations (in unidimensional approximation) allow for a quantitative determination of the specific internal energies and pressures in the case of optical detonation. (orig.) [de

  12. Chemical effects of a high CO2 concentration in oxy-fuel combustion of methane

    DEFF Research Database (Denmark)

    Glarborg, Peter; Bentzen, L.L.B.

    2008-01-01

    The oxidation of methane in an atmospheric-pres sure flow reactor has been studied experimentally under highly diluted conditions in N-2 and CO2, respectively. The stoichiometry was varied from fuel-lean to fuel-rich, and the temperatures covered the range 1200-1800 K. The results were interpreted...... CO2. The high local CO levels may have implications for near-burner corrosion and stagging, but increased problems with CO emission in oxy-fuel combustion are not anticipated....

  13. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor

    International Nuclear Information System (INIS)

    Dou Binlin; Song Yongchen; Liu Yingguang; Feng Cong

    2010-01-01

    The gas-solid reaction and breakthrough curve of CO 2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO 2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO 2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO 2 capture at 550 deg. C. Calcium oxide sorbent after reaction can be easily regenerated at 900 deg. C by pure N 2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO 2 were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  14. An Innovative Configuration for CO2 Capture by High Temperature Fuel Cells

    Directory of Open Access Journals (Sweden)

    Federico Rossi

    2014-09-01

    Full Text Available Many technological solutions have been proposed for CO2 capture in the last few years. Most of them are characterized by high costs in terms of energy consumption and, consequently, higher fossil fuel use and higher economic costs. High temperature fuel cells are technological solutions currently developed for energy production with low environmental impact. In CIRIAF—University of Perugia labs, cylindrical geometry, small-sized molten carbonate fuel cell (MCFC prototypes were built and tested with good energy production and lifetime performances. In the present work, an innovative application for MCFCs is proposed, and an innovative configuration for CO2 capture/separation is investigated. The plant scheme is based on a reformer and a cylindrical MCFC. MCFCs are the most suitable solutions, because CO2 is used in their operating cycle. An analysis in terms of energy consumption/kgCO2 captured is made by coupling the proposed configuration with a gas turbine plant. The proposed configuration is characterized by a theoretical energy consumption of about 500 kJ/kgCO2, which is quite lower than actual sequestration technologies. An experimental campaign will be scheduled to verify the theoretical findings.

  15. Magnetostriction of some cubic rare earth-Co2 compounds in high magnetic fields

    International Nuclear Information System (INIS)

    Moral, A. del; Melville, D.

    1975-01-01

    Magnetostriction measurements have been carried out in the cubic Laves phase compounds DyCo 2 , HoCo 2 and ErCo 2 from 10 K to well above their respective Neel temperatures Tsub(N). Pulsed magnetic fields up to 15 T (150kOe) were applied. The observed magnetostrictions are very large (approximately 10 -3 ) being similar to those found in the RFe 2 compounds. The measurements confirm the extremely high anisotropy of these materials. At the highest fields the polycrystalline samples are still undergoing rotational magnetization processes. The expected values of the saturation magnetostriction at O K are similar in sign and magnitude to those found in the corresponding rare earth metals. This fact and the scaling of magnetostriction with rare earth sublattice magnetization indicates that the rare earth ion is the main source of the magnetostriction. The metamagnetic transition above Tsub(N) has been studied, the relation between critical field and temperature being nonlinear for HoCo 2 and ErCo 2 . The compounds are highly anisotropic above Tsub(N) and all the features indicate that the field-induced phases are likely to be ferrimagnetic. (author)

  16. Transcritical CO2 power cycle – Effects of regenerative heating using turbine bleed gas at intermediate pressure

    International Nuclear Information System (INIS)

    Mondal, Subha; De, Sudipta

    2015-01-01

    For energy utilization from low temperature waste heat, CO 2 is a potential working fluid due to its lower critical temperature. In this work, assuming finite quantity of flue gas available at low temperature (200 °C), a thermodynamic model is developed for a transcritical CO 2 power cycle utilizing turbine bleed gas for regenerative heating. Analysis show that the cycle performance improves with higher value of bleed ratio. However, for a specified bleed pressure and bleed gas temperature at the regenerator exit, maximum practical value of bleed ratio may be fixed by considering the exponential growth of the regenerator size (specified by NTU (number of transfer unit)). Most significant observation is the existence of optimum bleed pressures corresponding to maximum 1st law efficiency or minimum cycle irreversibility for specified values of remaining cycle parameters. - Highlights: • Thermodynamic model for Transcritical CO 2 cycle with bleed gas are developed. • Effects of bleed ratio, pressure, and regenerator exit gas temperature are studied. • 1st and 2nd law efficiencies are estimated. • An optimum bleed pressure for maximum 1st and 2nd efficiencies is obtained. • Maximum value of 1st law efficiency is limited by regenerator size

  17. Highly efficient repetitively pulsed electric-discharge industrial CO2 laser

    International Nuclear Information System (INIS)

    Osipov, V V; Ivanov, M G; Lisenkov, V V; Platonov, V V

    2002-01-01

    The results of investigations aimed at the development of a repetitively pulsed CO 2 laser with an active medium volume of 1000 cm 3 pumped by a combined discharge are generalised. It is shown that, at pump pulse durations of 200-500 μs the optimal characteristics are achieved at active-medium pressures of 60-100 Torr. In this case, the laser efficiency at the initial stage of its operation can reach 22% and; if the energy dissipated in the region of the cathode potential drop is neglected, the efficiency is 28%. After emission of 3x10 5 pulses, the laser efficiency falls to 12%. It has been found that adding CO with a relative concentration [CO]/[CO 2 ] ∼0.75 increases the input and output power by almost 50%. The lasing efficiency is then 10%-12%, and the service life of the laser is by more than 10 6 pulses with a power decrease of no more than 10%. Adding hydrogen up to a concentration [H 2 ]/[CO 2 ] ∼10 leads to an increase in the energy supplied to the gas due to a decrease in the rate of ionisation processes. However, the optimal ratio is [H 2 ]/[CO 2 ] ∼ 1, at which the output power increases by 15%. In a long-term operating mode, the laser power is 1 kW at a peak power of 10 kW and an efficiency of 12%. (lasers)

  18. High efficiency pump combiner fabricated by CO2 laser splicing system

    Science.gov (United States)

    Zhu, Gongwen

    2018-02-01

    High power combiners are of great interest for high power fiber lasers and fiber amplifiers. With the advent of CO2 laser splicing system, power combiners are made possible with low manufacturing cost, low loss, high reliability and high performance. Traditionally fiber optical components are fabricated with flame torch, electrode arc discharge or filament heater. However, these methods can easily leave contamination on the fiber, resulting inconsistent performance or even catching fire in high power operations. The electrodes or filaments also degrade rapidly during the combiner manufacturing process. The rapid degradation will lead to extensive maintenance, making it unpractical or uneconomic for volume production. By contrast, CO2 laser is the cleanest heating source which provides reliable and repeatable process for fabricating fiber optic components including high power combiners. In this paper we present an all fiber end pumped 7x1 pump combiner fabricated by CO2 laser splicing system. The input pump fibers are 105/125 (core/clad diameters in μm) fibers with a core NA of 0.22. The output fiber is a 300/320 fiber with a core NA of 0.22. The average efficiency is 99.4% with all 7 ports more than 99%. The process is contamination-free and highly repeatable. To our best knowledge, this is the first report in the literature on power combiners fabricated by CO2 laser splicing system. It also has the highest reported efficiency of its kind.

  19. CO2 emission inventories for Chinese cities in highly urbanized areas compared with European cities

    International Nuclear Information System (INIS)

    Yu Wei; Pagani, Roberto; Huang Lei

    2012-01-01

    The international literature has paid significant attention to presenting China as the largest emitter of greenhouse gases (GHGs) in the world, despite having much lower per-capita emissions than the global average. In fact, the imbalance of economic development leads to diversity in GHG emissions profiles in different areas of China. This paper employs a common methodology, consistent with the Sustainable Energy Action Plan (SEAP) approved by the Covenant of Mayors (CoM), to estimate CO 2 emissions of four Chinese cities in highly urbanized areas from 2004 to 2010. The results show that the CO 2 emissions of all four cities are still rising and that secondary industries emit the most CO 2 in these cities. By comparing these data with the inventory results of two European cities, this paper further reveals that Chinese cities in highly urbanized areas contribute much higher per-capita emissions than their European competitors. Furthermore, the per-capita CO 2 emissions of the residential sector and private transport in these Chinese cities are growing rapidly, some of them approaching the levels of European cities. According to these findings, several policy suggestions considering regional disparities are provided that aim to reduce the CO 2 emissions of highly urbanized areas in China. - Highlights: ► An exemplary study of GHG emission inventory for Chinese cities. ► Estimate CO 2 emissions of Chinese city in highly urbanized areas from 2004 to 2010. ► The studied Chinese cities contribute higher per-capita emissions than European’s. ► Emissions of residential sector and private transport in China are growing rapidly. ► Several policy suggestions considering regional disparities are provided.

  20. Comprehensive study on the pressure dependence of shock wave plasma generation under TEA CO2 laser bombardment on metal sample

    International Nuclear Information System (INIS)

    Marpaung, A.M.; Kurniawan, H.; Tjia, M.O.; Kagawa, K.

    2001-01-01

    An experimental study has been carried out on the dynamical process taking place in the plasma generated by a TEA CO 2 laser (400 mJ, 100 ns) on a zinc target when surrounded by helium gas of pressure ranging from 2 Torr to 1 atm. Plasma characteristics were examined in detail on the emission lines of Zn I 481.0 nm and He I 587.6 nm by means of an unique time-resolved spatial distribution technique in addition to an ordinary time-resolved emission measurement technique. The results reveal, for the first time, persistent shock wave characteristics in all cases throughout the entire pressure range considered. Further analysis of the data has clarified the distinct characteristics of laser plasmas generated in different ranges of gas pressure. It is concluded that three types of shock wave plasma can be identified; namely, a target shock wave plasma in the pressure range from 2 Torr to around 50 Torr; a coupling shock wave plasma in the pressure range from around 50 Torr to 200 Torr and a gas breakdown shock wave plasma in the pressure range from around 200 Torr to 1 atm. These distinct characteristics are found to be ascribable to the different extents of the gas breakdown process taking place at the different gas pressures. These results, obtained for a TEA CO 2 laser, will provide a useful basis for the analyses of plasmas induced by other lasers. (author)

  1. The CO2 absorption spectrum in the 2.3 μm transparency window by high sensitivity CRDS: (II) Self-absorption continuum

    Science.gov (United States)

    Mondelain, D.; Vasilchenko, S.; Čermák, P.; Kassi, S.; Campargue, A.

    2017-01-01

    The CO2 absorption continuum near 2.3 μm is determined for a series of sub atmospheric pressures (250-750 Torr) by high sensitivity Cavity Ring Down Spectroscopy. An experimental procedure consisting in injecting successively a gas flow of CO2 and synthetic air, keeping constant the gas pressure in the CRDS cell, has been developed. This procedure insures a high stability of the spectra baseline by avoiding changes of the optical alignment due to pressure changes. The CO2 continuum was obtained as the difference between the CO2 absorption coefficient and a local lines simulation using a Voigt profile truncated at ±25 cm-1. Following the results of the preceding analysis of the CO2 rovibrational lines (Vasilchenko S et al. J Quant Spectrosc Radiat Transfer 10.1016/j.jqsrt.2016.07.002, a CO2 line list with intensities obtained by variational calculations and empirical line positions was preferred to the HITRAN line list. A quadratic pressure dependence of the absorption continuum is observed, with an average binary absorption coefficient increasing from 2 to 4×10-8 cm-1 amagat-2 between 4320 and 4380 cm-1. The obtained continuum is found in good agreement with a previous measurement using much higher densities (20 amagat) and a low resolution grating spectrograph and is consistent with values currently used in the analysis of Venus spectra.

  2. Modification of surface layers of copper under the action of the volumetric discharge initiated by an avalanche electron beam in nitrogen and CO2 at atmospheric pressure

    Science.gov (United States)

    Shulepov, M. A.; Akhmadeev, Yu. Kh.; Tarasenko, V. F.; Kolubaeva, Yu. A.; Krysina, O. V.; Kostyrya, I. D.

    2011-05-01

    The results of experimental investigations of the action of the volumetric discharge initiated by an avalanche electron beam on the surface of copper specimens are presented. The volumetric (diffuse) discharge in nitrogen and CO2 at atmospheric pressure was initiated by applying high voltage pulses of nanosecond duration to a tubular foil cathode. It has been found that the treatment of a copper surface by this type of discharge increases the hardness of the surface layer due to oxidation.

  3. Winter time burst of CO2 from the High Arctic soils of Svalbard

    DEFF Research Database (Denmark)

    Friborg, Thomas; Hansen, Birger; Elberling, Bo

    of relatively few measurements which appear to give small and constant emission rates. Further, most studies of the processes behind winter time emission of CO2 conclude that the flux during this time of year can be linked to the respiratory release of CO2 from soil micro organisms, which is temperature...... the winter at a high arctic location in Svalbard (78°N). Measurements were conducted in the field during the winter season of 2004-2005 and show reliable and continuous measurements of CO2 fluxes down to a level of 0.01 ìmol m-2 s-1 and good correspondence with other types of soil chambers. Our results...... indicate that a substantial part of the annual CO2 emission from the ecosystem occur during the freeze in period, where more CO2 is emitted from the soil over a few weeks than the accumulated flux for the rest of the winter. During the coldest part of the...

  4. Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

    Science.gov (United States)

    Santos, Bruna Marques Dos; Balbuena, Tiago Santana

    2017-01-06

    Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO 2 concentrations. Growth under a high concentration of CO 2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO 2 . Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO 2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO 2 . Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO 2 -enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO 2 -enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO 2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in

  5. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong

    2016-06-23

    While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

  6. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    Directory of Open Access Journals (Sweden)

    Venot Olivia

    2014-02-01

    Full Text Available Ultraviolet (UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm. Within the studied range of temperature, the CO2 cross section can vary by more than two orders of magnitude. This, in particular, makes the absorption of CO2 significant up to wavelengths as high as 230 nm, while it is negligible above 200 nm at 300 K. To investigate the influence of these new data on the photochemistry of exoplanets, we implemented the measured cross section into a 1D photochemical model. The model predicts that accounting for this temperature dependency of CO2 cross section can affect the computed abundances of NH3, CO2, and CO by one order of magnitude in the atmospheres of hot Jupiter and hot Neptune.

  7. The carbon curse: Are fuel rich countries doomed to high CO2 intensities?

    International Nuclear Information System (INIS)

    Friedrichs, Jörg; Inderwildi, Oliver R.

    2013-01-01

    The carbon curse is a new theory, related to but distinct from the resource curse. It states that fossil-fuel rich countries tend to follow more carbon-intensive developmental pathways than [if they were] fossil-fuel poor countries, due to a hitherto unappreciated syndrome of causal mechanisms. First, fuel rich countries emit significant amounts of CO 2 in the extraction of fuel and through associated wasteful practices such as gas flaring. Second, easy access to domestic fuel in such countries leads to crowding-out effects for their energy mix and economic structure (for example, abundant oil may displace other fuels from the energy mix and lead to the “Dutch Disease”). Third, fuel abundance weakens the economic incentive to invest in energy efficiency. Fourth, governments in fuel rich countries are under considerable pressure to grant uneconomic fuel consumption subsidies, which further augments the carbon intensity of their economic output. Due to the combined effect of these causal mechanisms, it is genuinely difficult for fuel rich countries to evade carbon-intensive developmental pathways. And yet there are remarkable exceptions like Norway. Such positive outliers indicate that the carbon curse is not destiny when appropriate policies are adopted. - Highlights: • Fuel rich countries appear doomed to high carbon intensity, for four reasons. • First, extractive emissions; and, second, fuel-related crowding-out effects. • Third, weaker incentives to invest in improvements of energy efficiency. • Fourth, significant pressure to grant uneconomic fuel consumption subsidies. • But the carbon curse is not destiny, as indicated by positive outliers like Norway

  8. Evidence for divergence of response in Indica, Japonica, and wild rice to high CO2 x temperature interaction

    Science.gov (United States)

    Previous studies suggest that the intraspecific variability of rice yield response to rising carbon dioxide concentration, [CO2], could serve as a basis of selection to improve genotypes for future high CO2 conditions. However, assessment of responses to elevated [CO2] must consider air temperature,...

  9. Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalyst

    Science.gov (United States)

    Gao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, Yuhan

    2017-10-01

    Although considerable progress has been made in carbon dioxide (CO2) hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The oxygen vacancies on the In2O3 surfaces activate CO2 and hydrogen to form methanol, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane number. The proximity of these two components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Moreover, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.

  10. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Li, Lain-Jong; Huang, Kuo-Wei

    2016-01-01

    for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open

  11. Functional genetic divergence in high CO2 adapted Emiliania huxleyi populations.

    Science.gov (United States)

    Lohbeck, Kai T; Riebesell, Ulf; Collins, Sinéad; Reusch, Thorsten B H

    2013-07-01

    Predicting the impacts of environmental change on marine organisms, food webs, and biogeochemical cycles presently relies almost exclusively on short-term physiological studies, while the possibility of adaptive evolution is often ignored. Here, we assess adaptive evolution in the coccolithophore Emiliania huxleyi, a well-established model species in biological oceanography, in response to ocean acidification. We previously demonstrated that this globally important marine phytoplankton species adapts within 500 generations to elevated CO2 . After 750 and 1000 generations, no further fitness increase occurred, and we observed phenotypic convergence between replicate populations. We then exposed adapted populations to two novel environments to investigate whether or not the underlying basis for high CO2 -adaptation involves functional genetic divergence, assuming that different novel mutations become apparent via divergent pleiotropic effects. The novel environment "high light" did not reveal such genetic divergence whereas growth in a low-salinity environment revealed strong pleiotropic effects in high CO2 adapted populations, indicating divergent genetic bases for adaptation to high CO2 . This suggests that pleiotropy plays an important role in adaptation of natural E. huxleyi populations to ocean acidification. Our study highlights the potential mutual benefits for oceanography and evolutionary biology of using ecologically important marine phytoplankton for microbial evolution experiments. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

  12. The potential effect of high atmospheric CO2 on soil fungi-invertebrate interactions

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Nováková, Alena; Jones, H.

    2002-01-01

    Roč. 8, - (2002), s. 339-344 ISSN 1354-1013 R&D Projects: GA AV ČR IAB6066903 Institutional research plan: CEZ:AV0Z6066911 Keywords : food web * global changes * high CO2 Subject RIV: EH - Ecology, Behaviour Impact factor: 3.398, year: 2002

  13. Effects of CO 2 on a High Performance Hollow-Fiber Membrane for Natural Gas Purification

    KAUST Repository

    Omole, Imona C.; Adams, Ryan T.; Miller, Stephen J.; Koros, William J.

    2010-01-01

    A 6FDA-based, cross-linkable polyimide was characterized in the form of a defect-free asymmetric hollow-fiber membrane. The novel membrane was cross-linked at various temperatures and tested for natural gas purification in the presence of high CO2

  14. Absorption capacity and viscosity for CO_2 capture process using high concentrated PZ-DEAE aqueous solution

    International Nuclear Information System (INIS)

    Fu, Dong; Wang, LeMeng; Mi, ChenLu; Zhang, Pan

    2016-01-01

    Highlights: • Absorption of CO_2 in high concentrated DEAE-PZ aqueous solutions were measured. • Viscosities of CO_2-unloaded and CO_2-loaded DEAE-PZ aqueous solutions were measured. • Weiland equation was used to calculate the viscosities. • Effects of temperature, concentration and CO_2 loading on viscosity were demonstrated. - Abstract: The absorption capacity of CO_2 in piperazine (PZ) promoted 2-diethylaminoethanol (DEAE) aqueous solution was measured. The viscosities of both CO_2-unloaded and CO_2-loaded PZ-DEAE aqueous solutions were measured and then modelled. The temperatures ranged from 303.2 K to 323.2 K. The mass fraction of PZ and DEAE respectively ranged from 0 to 0.075 and 0.3 to 0.5. The temperature and concentration dependences of absorption capacity were determined. The effects of temperature, mass fraction and CO_2 loading on viscosities are demonstrated.

  15. Research and survey report of FY 1997 on the CO2 balance for high-temperature CO2 fixation and utilization technology; 1997 nendo chosa hokokusho (nisanka tanso koon bunri gijutsu ni okeru CO2 balance ni kansuru chosa kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The purpose of this research is to clarify the application condition and effectiveness of high-temperature CO2 fixation and utilization technology. To evaluate the present process, it was compared with others, such as separation using a polymer membrane, physico-chemical absorption process, adsorption process, hydrogen contact reduction process, and biological fixation. The development trends of absorption, membrane, adsorption, and cryogenic separation were investigated. The questionnaire was carried out about the separation technologies which are in the stage of performance test using actual gas, to arrange and compare the data and information. The current trends of chemical and biological CO2 fixation and utilization technology were also investigated for arranging the subjects. High-temperature CO2 disposal by the carbonation in concrete waste has been studied, to clarify its application conditions and effectiveness. In order to compare the separation technologies, treatment processes of CO2 in the exhaust gas from boilers of LNG power generation and coal fired power generation were simulated. These processes were simulated by ASPEN PLUS for the modeling. Trends of application of ASPEN PLUS and collection of information were surveyed by participating in the ASPEN WORLD. 103 refs., 51 figs., 55 tabs.

  16. Carbon Dots/NiCo2 O4 Nanocomposites with Various Morphologies for High Performance Supercapacitors.

    Science.gov (United States)

    Wei, Ji-Shi; Ding, Hui; Zhang, Peng; Song, Yan-Fang; Chen, Jie; Wang, Yong-Gang; Xiong, Huan-Ming

    2016-11-01

    A series of carbon dots/NiCo 2 O 4 composites with various morphologies are prepared and tested for supercapacitors. These samples have good electrical conductivities and efficient ions transport paths, so they exhibit high specific capacitances, superior rate performances, and high cycling stabilities. The optimal composite for hybrid supercapacitor exhibits a high energy density up to 62.0 Wh kg -1 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Skeletal mineralogy of coral recruits under high temperature and pCO2

    Science.gov (United States)

    Foster, T.; Clode, P. L.

    2016-03-01

    Aragonite, which is the polymorph of CaCO3 precipitated by modern corals during skeletal formation, has a higher solubility than the more stable polymorph calcite. This higher solubility may leave animals that produce aragonitic skeletons more vulnerable to anthropogenic ocean acidification. It is therefore important to determine whether scleractinian corals have the plasticity to adapt and produce calcite in their skeletons in response to changing environmental conditions. Both high pCO2 and lower Mg / Ca ratios in seawater are thought to have driven changes in the skeletal mineralogy of major marine calcifiers in the past ˜ 540 Ma. Experimentally reduced Mg / Ca ratios in ambient seawater have been shown to induce some calcite precipitation in both adult and newly settled modern corals; however, the impact of high pCO2 on the mineralogy of recruits is unknown. Here we determined the skeletal mineralogy of 1-month-old Acropora spicifera coral recruits grown under high temperature (+3 °C) and pCO2 (˜ 900 µatm) conditions, using X-ray diffraction and Raman spectroscopy. We found that newly settled coral recruits produced entirely aragonitic skeletons regardless of the treatment. Our results show that elevated pCO2 alone is unlikely to drive changes in the skeletal mineralogy of young corals. Not having an ability to switch from aragonite to calcite precipitation may leave corals and ultimately coral reef ecosystems more susceptible to predicted ocean acidification. An important area for prospective research would be the investigation of the combined impact of high pCO2 and reduced Mg / Ca ratio on coral skeletal mineralogy.

  18. Porous materials as high performance adsorbents for CO2 capture, gas separation and purification

    Science.gov (United States)

    Wang, Jun

    Global warming resulted from greenhouse gases emission has received a widespread attention. Among the greenhouse gases, CO2 contributes more than 60% to global warming due to its huge emission amount. The flue gas contains about 15% CO2 with N2 as the balance. If CO2 can be separated from flue gas, the benefit is not only reducing the global warming effect, but also producing pure CO2 as a very useful industry raw material. Substantial progress is urgent to be achieved in an industrial process. Moreover, energy crisis is one of the biggest challenges for all countries due to the short life of fossil fuels, such as, petroleum will run out in 50 years and coal will run out in 150 years according to today's speed. Moreover, the severe pollution to the environment caused by burning fossil fuels requires us to explore sustainable, environment-friendly, and facile energy sources. Among several alternative energy sources, natural gas is one of the most promising alternative energy sources due to its huge productivity, abundant feed stock, and ease of generation. In order to realize a substantial adsorption process in industry, synthesis of new adsorbents or modification of existing adsorbent with improved properties has become the most critical issue. This dissertation reports systemic characterization and development of five serials of novel adsorbents with advanced adsorption properties. In chapter 2, nitrogen-doped Hypercross-linking Polymers (HCPs) have been synthesized successfully with non-carcinogenic chloromethyl methyl ether (CME) as the cross-linking agent within a single step. Texture properties, surface morphology, CO2/N2 selectivity, and adsorption heat have been presented and demonstrated properly. A comprehensive discussion on factors that affect the CO2 adsorption and CO2/N 2 separation has also been presented. It was found that high micropore proportion and N-content could effectively enhance CO2 uptake and CO2/N2 separation selectivity. In chapter 3, a

  19. Data and modelling requirements for CO2 inversions using high-frequency data

    International Nuclear Information System (INIS)

    Law, R.M.; Rayner, P.J.; Steele, L.P.; Enting, I.G.

    2003-01-01

    We explore the future possibilities for CO 2 source estimation from atmospheric concentration data by performing synthetic data experiments. Synthetic data are used to test seasonal CO 2 inversions using high-frequency data. Monthly CO 2 sources over the Australian region are calculated for inversions with data at 4-hourly frequency and averaged over 1 d, 2.5 d, 5 d, 12.17 d and 1 month. The inversion quality, as determined by bias and uncertainty, is degraded when averaging over longer periods. This shows the value of the strong but relatively short-lived signals present in high-frequency records that are removed in averaged and particularly filtered records. Sensitivity tests are performed in which the synthetic data are 'corrupted' to simulate systematic measurement errors such as intercalibration differences or to simulate transport modelling errors. The inversion is also used to estimate the effect of calibration offsets between sites. We find that at short data-averaging periods the inversion is reasonably robust to measurement-type errors. For transport-type errors, the best results are achieved for synoptic (2-5 d) timescales. Overall the tests indicate that improved source estimates should be possible by incorporating continuous measurements into CO 2 inversions

  20. High-speed high-efficiency 500-W cw CO2 laser hermetization of metal frames of microelectronics devices

    Science.gov (United States)

    Levin, Andrey V.

    1996-04-01

    High-speed, efficient method of laser surface treatment has been developed using (500 W) cw CO2 laser. The principal advantages of CO2 laser surface treatment in comparison with solid state lasers are the basis of the method. It has been affirmed that high efficiency of welding was a consequence of the fundamental properties of metal-IR-radiation (10,6 mkm) interaction. CO2 laser hermetization of metal frames of microelectronic devices is described as an example of the proposed method application.

  1. Ultrathin porous NiCo2O4 nanosheet arrays on flexible carbon fabric for high-performance supercapacitors.

    Science.gov (United States)

    Du, Jun; Zhou, Gang; Zhang, Haiming; Cheng, Chao; Ma, Jianmin; Wei, Weifeng; Chen, Libao; Wang, Taihong

    2013-08-14

    NiCo2O4 with higher specific capacitance is an excellent pseudocapacitive material. However, the bulk NiCo2O4 material prevents the achievement of high energy desity and great rate performance due to the limited electroactive surface area. In this work, NiCo2O4 nanosheet arrays were deposited on flexible carbon fabric (CF) as a high-performance electrode for supercapacitors. The NiCo2O4 arrays were constructed by interconnected ultrathin nanosheets (10 nm) with many interparticle pores. The porous feature of NiCo2O4 nanosheets increases the amount of electroactive sites and facilitates the electrolyte penetration. Hence, the NiCo2O4/CF composites exhibited a high specific capacitance of 2658 F g(-1) (2 A g(-1)), good rate performance, and superior cycling life, suggesting the NiCo2O4/CF is a promising electrode material for flexible electrochemical capacitors.

  2. Armazenamento refrigerado de morango submetido a altas concentrações de CO2 Cold storage of strawberries under high CO2 concentrations

    Directory of Open Access Journals (Sweden)

    Luis C Cunha Junior

    2012-12-01

    strawberries. However, fruits and vegetables are not currently handled under cold chain in Brazil and, when it happens, it used to be at 10 to 15ºC. The goal of this work was to evaluate the quality and the shelf life of 'Oso Grande' strawberry at 10ºC associated to high carbon dioxide concentrations. Strawberries were randomized, chilled and stored at 10ºC in hermetic mini-chambers to apply the CO2 concentrations (0.03, 10, 20, 40 and 80% plus 20% O2. Strawberries were analyzed every two days while they were proper to consumption. The shelf life for strawberries at 20 and 40% CO2 was 8 days, while those at 0.03% CO2 lasted only two days. Strawberries at 80% CO2 maintained good appearance for 6 days, but they were considered unsuitable for consumption due to high levels of acetaldehyde (40.92 µg g-1 and ethanol (1,053 µg g-1 that gave evidence of fermentation process. The weight loss was less than 2% showing how efficient was the method used to control the relative humidity during the storage. Strawberries at 0.03 and 80% CO2 levels showed higher firmness loss. Those fruits lost 40% of the initial firmness. Strawberries at 20 and 40% CO2 lost only 28% of initial firmness. Despite of the statistical effect of the treatments in the external color it was not visually perceptible. Strawberries stored at 10ºC and 40% CO2 plus 20% O2 kept the marketable quality during 8 days.

  3. High-resolution quantification of atmospheric CO2 mixing ratios in the Greater Toronto Area, Canada

    Science.gov (United States)

    Pugliese, Stephanie C.; Murphy, Jennifer G.; Vogel, Felix R.; Moran, Michael D.; Zhang, Junhua; Zheng, Qiong; Stroud, Craig A.; Ren, Shuzhan; Worthy, Douglas; Broquet, Gregoire

    2018-03-01

    Many stakeholders are seeking methods to reduce carbon dioxide (CO2) emissions in urban areas, but reliable, high-resolution inventories are required to guide these efforts. We present the development of a high-resolution CO2 inventory available for the Greater Toronto Area and surrounding region in Southern Ontario, Canada (area of ˜ 2.8 × 105 km2, 26 % of the province of Ontario). The new SOCE (Southern Ontario CO2 Emissions) inventory is available at the 2.5 × 2.5 km spatial and hourly temporal resolution and characterizes emissions from seven sectors: area, residential natural-gas combustion, commercial natural-gas combustion, point, marine, on-road, and off-road. To assess the accuracy of the SOCE inventory, we developed an observation-model framework using the GEM-MACH chemistry-transport model run on a high-resolution grid with 2.5 km grid spacing coupled to the Fossil Fuel Data Assimilation System (FFDAS) v2 inventories for anthropogenic CO2 emissions and the European Centre for Medium-Range Weather Forecasts (ECMWF) land carbon model C-TESSEL for biogenic fluxes. A run using FFDAS for the Southern Ontario region was compared to a run in which its emissions were replaced by the SOCE inventory. Simulated CO2 mixing ratios were compared against in situ measurements made at four sites in Southern Ontario - Downsview, Hanlan's Point, Egbert and Turkey Point - in 3 winter months, January-March 2016. Model simulations had better agreement with measurements when using the SOCE inventory emissions versus other inventories, quantified using a variety of statistics such as correlation coefficient, root-mean-square error, and mean bias. Furthermore, when run with the SOCE inventory, the model had improved ability to capture the typical diurnal pattern of CO2 mixing ratios, particularly at the Downsview, Hanlan's Point, and Egbert sites. In addition to improved model-measurement agreement, the SOCE inventory offers a sectoral breakdown of emissions

  4. High-resolution quantification of atmospheric CO2 mixing ratios in the Greater Toronto Area, Canada

    Directory of Open Access Journals (Sweden)

    S. C. Pugliese

    2018-03-01

    Full Text Available Many stakeholders are seeking methods to reduce carbon dioxide (CO2 emissions in urban areas, but reliable, high-resolution inventories are required to guide these efforts. We present the development of a high-resolution CO2 inventory available for the Greater Toronto Area and surrounding region in Southern Ontario, Canada (area of  ∼ 2.8 × 105 km2, 26 % of the province of Ontario. The new SOCE (Southern Ontario CO2 Emissions inventory is available at the 2.5 × 2.5 km spatial and hourly temporal resolution and characterizes emissions from seven sectors: area, residential natural-gas combustion, commercial natural-gas combustion, point, marine, on-road, and off-road. To assess the accuracy of the SOCE inventory, we developed an observation–model framework using the GEM-MACH chemistry–transport model run on a high-resolution grid with 2.5 km grid spacing coupled to the Fossil Fuel Data Assimilation System (FFDAS v2 inventories for anthropogenic CO2 emissions and the European Centre for Medium-Range Weather Forecasts (ECMWF land carbon model C-TESSEL for biogenic fluxes. A run using FFDAS for the Southern Ontario region was compared to a run in which its emissions were replaced by the SOCE inventory. Simulated CO2 mixing ratios were compared against in situ measurements made at four sites in Southern Ontario – Downsview, Hanlan's Point, Egbert and Turkey Point – in 3 winter months, January–March 2016. Model simulations had better agreement with measurements when using the SOCE inventory emissions versus other inventories, quantified using a variety of statistics such as correlation coefficient, root-mean-square error, and mean bias. Furthermore, when run with the SOCE inventory, the model had improved ability to capture the typical diurnal pattern of CO2 mixing ratios, particularly at the Downsview, Hanlan's Point, and Egbert sites. In addition to improved model–measurement agreement, the SOCE inventory offers a

  5. A Highly Stable Microporous Covalent Imine Network Adsorbent for Natural Gas Upgrading and Flue Gas CO2 Capture

    KAUST Repository

    Das, Swapan Kumar

    2016-06-06

    The feasible capture and separation of CO2 and N2 from CH4 is an important task for natural gas upgrading and the control of greenhouse gas emissions. Here, we studied the microporous covalent imine networks (CIN) material prepared through Schiff base condensation and exhibited superior chemical robustness under both acidic and basic conditions and high thermal stability. The material possesses a relatively uniform nanoparticle size of approximately 70 to 100 nm. This network featured permanent porosity with a high surface area (722 m2g-1) and micropores. A single-component gas adsorption study showed enhanced CO2 and CH4 uptakes of 3.32 mmol/g and 1.14 mmol/g, respectively, at 273 K and 1 bar, coupled with high separation selectivities for CO2/CH4, CH4/N2, and CO2/N2 of 23, 11.8 and 211, respectively. The enriched Lewis basicity in the porous skeletons favours the interaction of quadrupolar CO2 and polarizable CH4, resulting in enhanced CH4 and CO2 uptake and high CH4/N2, CO2/CH4 and CO2/N2 selectivities. Breakthrough experiments showed high CO2/CH4, CH4/N2 and CO2/N2 selectivities of 7.29, 40 and 125, respectively, at 298 K and 1 bar. High heats of adsorption for CH4 and CO2 (QstCH4; 32.61 kJ mol-1 and QstCO2; 42.42 kJ mol-1) provide the ultimate validation for the high selectivity. To the best of our knowledge, such a versatile adsorbent material that displays both enhanced uptake and selectivity for a variety of binary gas mixtures, including CO2/ CH4, CO2/N2 and CH4/N2, has not been extensively explored.

  6. Magnetic properties and effect of pressure on the electronic state of EuCo2Ge2

    Science.gov (United States)

    Ashitomi, Y.; Kakihana, M.; Honda, F.; Nakamura, A.; Aoki, D.; Uwatoko, Y.; Nakashima, M.; Amako, Y.; Takeuchi, T.; Kida, T.; Tahara, T.; Hagiwara, M.; Haga, Y.; Hedo, M.; Nakama, T.; Ōnuki, Y.

    2018-05-01

    EuCo2Ge2 with the tetragonal structure is a Eu-divalent antiferromagnet with the Néel temperature TN = 23 K. The magnetic easy-axis corresponds to the [100] direction (a-axis), while the [001] direction (c-axis) is a hard-axis. The magnetization for H∥ [ 100 ] indicates a metamagnetic transition at 25 kOe and saturates above 75 kOe. On the other hand, the hard-axis magnetization increases approximately linearly and saturates above 110 kOe. The magnetic phase diagram was constructed. A characteristic feature in EuCo2Ge2 is known as a valence transition under pressure, from Eu 2+δ to Eu 3 - δ ‧(δ, δ ‧ electronic state is changed into a moderate heavy fermion state and approaches the nearly trivalent electronic state.

  7. Seagrass (Posidonia oceanica) seedlings in a high-CO2 world: from physiology to herbivory

    KAUST Repository

    Hernán, Gema

    2016-12-01

    Under future increased CO2 concentrations, seagrasses are predicted to perform better as a result of increased photosynthesis, but the effects in carbon balance and growth are unclear and remain unexplored for early life stages such as seedlings, which allow plant dispersal and provide the potential for adaptation under changing environmental conditions. Furthermore, the outcome of the concomitant biochemical changes in plant-herbivore interactions has been poorly studied, yet may have important implications in plant communities. In this study we determined the effects of experimental exposure to current and future predicted CO2 concentrations on the physiology, size and defense strategies against herbivory in the earliest life stage of the Mediterranean seagrass Posidonia oceanica. The photosynthetic performance of seedlings, assessed by fluorescence, improved under increased pCO2 conditions after 60 days, although these differences disappeared after 90 days. Furthermore, these plants exhibited bigger seeds and higher carbon storage in belowground tissues, having thus more resources to tolerate and recover from stressors. Of the several herbivory resistance traits measured, plants under high pCO2 conditions had a lower leaf N content but higher sucrose. These seedlings were preferred by herbivorous sea urchins in feeding trials, which could potentially counteract some of the positive effects observed.

  8. Seagrass (Posidonia oceanica) seedlings in a high-CO2 world: from physiology to herbivory.

    Science.gov (United States)

    Hernán, Gema; Ramajo, Laura; Basso, Lorena; Delgado, Antonio; Terrados, Jorge; Duarte, Carlos M; Tomas, Fiona

    2016-12-01

    Under future increased CO 2 concentrations, seagrasses are predicted to perform better as a result of increased photosynthesis, but the effects in carbon balance and growth are unclear and remain unexplored for early life stages such as seedlings, which allow plant dispersal and provide the potential for adaptation under changing environmental conditions. Furthermore, the outcome of the concomitant biochemical changes in plant-herbivore interactions has been poorly studied, yet may have important implications in plant communities. In this study we determined the effects of experimental exposure to current and future predicted CO 2 concentrations on the physiology, size and defense strategies against herbivory in the earliest life stage of the Mediterranean seagrass Posidonia oceanica. The photosynthetic performance of seedlings, assessed by fluorescence, improved under increased pCO 2 conditions after 60 days, although these differences disappeared after 90 days. Furthermore, these plants exhibited bigger seeds and higher carbon storage in belowground tissues, having thus more resources to tolerate and recover from stressors. Of the several herbivory resistance traits measured, plants under high pCO 2 conditions had a lower leaf N content but higher sucrose. These seedlings were preferred by herbivorous sea urchins in feeding trials, which could potentially counteract some of the positive effects observed.

  9. Toward reduced transport errors in a high resolution urban CO2 inversion system

    Directory of Open Access Journals (Sweden)

    Aijun Deng

    2017-05-01

    Full Text Available We present a high-resolution atmospheric inversion system combining a Lagrangian Particle Dispersion Model (LPDM and the Weather Research and Forecasting model (WRF, and test the impact of assimilating meteorological observation on transport accuracy. A Four Dimensional Data Assimilation (FDDA technique continuously assimilates meteorological observations from various observing systems into the transport modeling system, and is coupled to the high resolution CO2 emission product Hestia to simulate the atmospheric mole fractions of CO2. For the Indianapolis Flux Experiment (INFLUX project, we evaluated the impact of assimilating different meteorological observation systems on the linearized adjoint solutions and the CO2 inverse fluxes estimated using observed CO2 mole fractions from 11 out of 12 communications towers over Indianapolis for the Sep.-Nov. 2013 period. While assimilating WMO surface measurements improved the simulated wind speed and direction, their impact on the planetary boundary layer (PBL was limited. Simulated PBL wind statistics improved significantly when assimilating upper-air observations from the commercial airline program Aircraft Communications Addressing and Reporting System (ACARS and continuous ground-based Doppler lidar wind observations. Wind direction mean absolute error (MAE decreased from 26 to 14 degrees and the wind speed MAE decreased from 2.0 to 1.2 m s–1, while the bias remains small in all configurations (< 6 degrees and 0.2 m s–1. Wind speed MAE and ME are larger in daytime than in nighttime. PBL depth MAE is reduced by ~10%, with little bias reduction. The inverse results indicate that the spatial distribution of CO2 inverse fluxes were affected by the model performance while the overall flux estimates changed little across WRF simulations when aggregated over the entire domain. Our results show that PBL wind observations are a potent tool for increasing the precision of urban meteorological reanalyses

  10. High Arctic Forests During the Middle Eocene Supported by ~400 ppm Atmospheric CO2

    Science.gov (United States)

    Maxbauer, D. P.; Royer, D. L.; LePage, B. A.

    2013-12-01

    Fossils from Paleogene High Arctic deposits provide some of the clearest evidence for greenhouse climates and offer the potential to improve our understanding of Earth system dynamics in a largely ice-free world. One of the most well-known and exquisitely-preserved middle Eocene (47.9-37.8 Myrs ago) polar forest sites, Napartulik, crops out on eastern Axel Heiberg Island (80 °N), Nunavut, Canada. An abundance of data from Napartulik suggest mean annual temperatures of up to 30 °C warmer than today and atmospheric water loads 2× above current levels. Despite this wealth of paleontological and paleoclimatological data, there are currently no direct constraints on atmospheric CO2 levels for Napartulik or any other polar forest site. Here we apply a new plant gas-exchange model to Metasequoia (dawn redwood) leaves to reconstruct atmospheric CO2 from six fossil forests at Napartulik. Individual reconstructions vary between 405-489 ppm with a site mean of 437 ppm (337-564 ppm at 95% confidence). These estimates represent the first direct constraints on CO2 for polar fossil forests and suggest that the temperate conditions present at Napartulik during the middle Eocene were maintained under CO2 concentrations ~1.6× above pre-industrial levels. Our results strongly support the case that long-term climate sensitivity to CO2 in the past was sometimes high, even during largely ice-free periods, highlighting the need to better understand the climate forcing and feedback mechanisms responsible for this amplification.

  11. The CO_2 absorption spectrum in the 2.3 µm transparency window by high sensitivity CRDS: (II) Self-absorption continuum

    International Nuclear Information System (INIS)

    Mondelain, D.; Vasilchenko, S.; Čermák, P.; Kassi, S.; Campargue, A.

    2017-01-01

    The CO_2 absorption continuum near 2.3 µm is determined for a series of sub atmospheric pressures (250–750 Torr) by high sensitivity Cavity Ring Down Spectroscopy. An experimental procedure consisting in injecting successively a gas flow of CO_2 and synthetic air, keeping constant the gas pressure in the CRDS cell, has been developed. This procedure insures a high stability of the spectra baseline by avoiding changes of the optical alignment due to pressure changes. The CO_2 continuum was obtained as the difference between the CO_2 absorption coefficient and a local lines simulation using a Voigt profile truncated at ±25 cm"−"1. Following the results of the preceding analysis of the CO_2 rovibrational lines (Vasilchenko S et al. J Quant Spectrosc Radiat Transfer (10.1016/j.jqsrt.2016.07.002), a CO_2 line list with intensities obtained by variational calculations and empirical line positions was preferred to the HITRAN line list. A quadratic pressure dependence of the absorption continuum is observed, with an average binary absorption coefficient increasing from 2 to 4×10"−"8 cm"−"1 amagat"−"2 between 4320 and 4380 cm"−"1. The obtained continuum is found in good agreement with a previous measurement using much higher densities (20 amagat) and a low resolution grating spectrograph and is consistent with values currently used in the analysis of Venus spectra. - Highlights: • The CO_2 absorption continuum is measured by CRDS in the 2.3 µm window. • The achieved sensitivity and stability allow measurements at sub-atmospheric pressure. • The absorption coefficient is on the order of 3×10"−"8 cm"−"1 amagat"−"2 near 4350 cm"−"1. • A good agreement is obtained with previous results at much higher density (20 amagat).

  12. A system for high-quality CO2 isotope analyses of air samples collected by the CARIBIC Airbus A340-600.

    Science.gov (United States)

    Assonov, S; Taylor, P; Brenninkmeijer, C A M

    2009-05-01

    In 2007, JRC-IRMM began a series of atmospheric CO2 isotope measurements, with the focus on understanding instrumental effects, corrections as well as metrological aspects. The calibration approach at JRC-IRMM is based on use of a plain CO2 sample (working reference CO2) as a calibration carrier and CO2-air mixtures (in high-pressure cylinders) to determine the method-related correction under actual analytical conditions (another calibration carrier, in the same form as the samples). Although this approach differs from that in other laboratories, it does give a direct link to the primary reference NBS-19-CO2. It also helps to investigate the magnitude and nature for each of the instrumental corrections and allows for the quantification of the uncertainty introduced. Critical tests were focused on the instrumental corrections. It was confirmed that the use of non-symmetrical capillary crimping (an approach used here to deal with small samples) systematically modifies delta13C(CO2) and delta18O(CO2), with a clear dependence on the amount of extracted CO2. However, the calibration of CO2-air mixtures required the use of the symmetrical dual-inlet mode. As a proof of our approach, we found that delta13C(CO2) on extracts from mixtures agreed (within 0.010 per thousand) with values obtained from the 'mother' CO2 used for the mixtures. It was further found that very low levels of hydrocarbons in the pumping systems and the isotope ratio mass spectrometry (IRMS) instrument itself were critical. The m/z 46 values (consequently the calculated delta18O(CO2) values) are affected by several other effects with traces of air co-trapped with frozen CO2 being the most critical. A careful cryo-distillation of the extracted CO2 is recommended. After extensive testing, optimisation, and routine automated use, the system was found to give precise data on air samples that can be traced with confidence to the primary standards. The typical total combined uncertainty in delta13C(CO2) and

  13. Influence of shielding gas pressure on welding characteristics in CO2 laser-MIG hybrid welding process

    Science.gov (United States)

    Chen, Yanbin; Lei, Zhenglong; Li, Liqun; Wu, Lin

    2006-01-01

    The droplet transfer behavior and weld characteristics have been investigated under different pressures of shielding gas in CO2 laser and metal inert/active gas (laser-MIG) hybrid welding process. The experimental results indicate that the inherent droplet transfer frequency and stable welding range of conventional MIG arc are changed due to the interaction between CO2 laser beam and MIG arc in laser-MIG hybrid welding process, and the shielding gas pressure has a crucial effect on welding characteristics. When the pressure of shielding gas is low in comparison with MIG welding, the frequency of droplet transfer decreases, and the droplet transfer becomes unstable in laser-MIG hybrid welding. So the penetration depth decreases, which shows the characteristic of unstable hybrid welding. However, when the pressure of shielding gas increases to a critical value, the hybrid welding characteristic is changed from unstable hybrid welding to stable hybrid welding, and the frequency of droplet transfer and the penetration depth increase significantly.

  14. Technology of discharge and laser resonators for high power CO2 lasers. Koshutsuryoku CO2 laser ni tsukawareru hoden reiki laser kyoshinki gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Y.; Kuzumoto, M. (Mitsubishi Electric Corp., Tokyo (Japan))

    1994-03-20

    This paper describes discharge excitation technology and resonator technology as basic technologies for high power CO2 lasers. As a result of progress in high-frequency power element techniques, the discharge excitation technology now generally uses laser excitation using AC discharge of capacity coupling type. Its representative example is silent discharge (SD) excitation. This is a system to excite laser by applying high voltages with as high frequency as 100 kHz to 1 MHz across a pair of electrodes covered with a dielectric material. The system maintains stability in discharge even if power supply voltage amplitude is modulated, and easily provides pulse outputs. Discharge excitation for diffusion cooled type CO2 laser generates a discharge in a gap with a gap length of about 2 mm, and can perform gas cooling by means of thermal conduction of gas, whereas a compact resonator can be fabricated. A resonator for the diffusion cooled type CO2 laser eliminates gas circulation and cooling systems, hence the device can be made more compact. A report has been given that several of these compact resonators were combined, from which a laser output of 85W was obtained by using RF discharge of 2kW. 43 refs., 21 figs.

  15. Summer Distribution of Co2 Partial Pressure In The Ross Sea, Antarctica, and Relations With Biological Activity

    Science.gov (United States)

    Sandrini, S.; Tositti, L.; Tubertini, O.; Ceradini, S.; Palucci, A.; Barbini, R.; Fantoni, R.; Colao, F.; Ferrari, G. M.

    The oceans play a key role in the processes responsible for global climate changes, in fact the oceanic uptake of anthropogenic atmospheric carbon dioxide is estimated to be 17-39The Southern Ocean and Antarctic marginal seas are considered to absorb up to half of this fraction. The Ross Sea, during the summer pack-ice melting, expe- riences rapid seasonal outgrowths, giving rise to phytoplankton blooms, especially in polynya areas near the coast line. This has a direct influence on pCO2 concentration in surface water, and hence on CO2 fluxes between ocean and atmosphere. Both the Ross Sea and the Southern Ocean transect between New Zealand and Antarctica are sys- tematically investigated during Italian Antarctic oceanographic campaigns onboard of the R/V Italica. During the XVI expedition, which took place in January and Febru- ary 2001, simultaneous measurements of surface pCO2 and Chlorophyll-a by laser remote-sensing apparatus were collected. Chlorophyll-a and pCO2 showed a general anticorrelation along the cruise. The survey has revealed the presence of high produc- tive regions in the polynya and close to the ice edge. The linear regression analysis of the chl-a vs pCO2 values improved our knowledge of the time evolution of the phyto- planktonic growth, independently measured by means of the laser yield, thus allowing for discrimination between different initial and final blooms in the Antarctic Ross Sea. The results obtained are here presented and discussed. They confirm the importance of biological production in the net absorption of atmospheric CO2 in continental shelf zones.

  16. In-operando elucidation of bimetallic CoNi nanoparticles during high-temperature CH 4 /CO 2 reaction

    KAUST Repository

    Al-Sabban, Bedour

    2017-05-02

    Dry reforming of methane (DRM) proceeds via CH4 decomposition to leave surface carbon species, followed by their removal with CO2-derived species. Reactivity tuning for stoichiometric CH4/CO2 reactants was attempted by alloying the non-noble metals Co and Ni, which have high affinity with CO2 and high activity for CH4 decomposition, respectively. This study was focused on providing evidence of the capturing surface coverage of the reactive intermediates and the associated structural changes of the metals during DRM at high temperature using in-operando X-ray absorption spectroscopy (XAS). On the Co catalysts, the first-order effects with respect to CH4 pressure and negative-order effects with respect to CO2 pressure on the DRM rate are consistent with the competitive adsorption of the surface oxygen species on the same sites as the CH4 decomposition reaction. The Ni surface provides comparatively higher rates of CH4 decomposition and the resultant DRM than the Co catalyst but leaves some deposited carbon on the catalyst surface. In contrast, the bimetallic CoNi catalyst exhibits reactivity towards the DRM but with kinetic orders resembling Co catalyst, producing negligible carbon deposition by balancing CH4 and CO2 activation. The in-operando X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements confirmed that the Co catalyst was progressively oxidized from the surface to the bulk with reaction time, whereas CoNi and Ni remained relatively reduced during DRM. Density functional theory (DFT) calculation considering the high reaction temperature for DRM confirmed the unselective site arrangement between Co and Ni atoms in both the surface and bulk of the alloy nanoparticle (NP). The calculated heat of oxygen chemisorption became more exothermic in the order of Ni, CoNi, Co, consistent with the catalytic behavior. The comprehensive experimental and theoretical evidence provided herein clearly suggests

  17. One-step synthesis of dimethyl ether from the gas mixture containing CO2 with high space velocity

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lin, Bo-Jhih; Lee, How-Ming; Huang, Men-Han

    2012-01-01

    Highlights: ► A bifunctional catalyst for DME synthesis is prepared using a coprecipitation method. ► The DME synthesis from syngas at a high space velocity of is investigated. ► The reaction is dominated by chemical kinetics at lower reaction temperatures. ► Thermodynamic equilibrium governs the reaction at higher temperatures. ► 0.2 g of ZSM5 is sufficient to be blended with 1 g of the catalyst for DME synthesis. -- Abstract: Dimethyl ether (DME) has been considered as a potential hydrogen carrier used in fuel cells; it can also be consumed as a diesel substitute or chemicals. To develop the technique of DME synthesis, a bifunctional Cu–ZnO–Al 2 O 3 /ZSM5 catalyst is prepared using a coprecipitation method. The reaction characteristics of DME synthesis from syngas at a high space velocity of 15,000 mL (g cat h) −1 are investigated and the effects of reaction temperature, pressure, CO 2 concentration and ZSM5 amount on the synthesis are taken into account. The results suggest that an increase in CO 2 concentration in the feed gas substantially decreases the DME formation. The optimum reaction temperature always occurs at 225 °C, regardless of what the pressure is. It is thus recognized that the DME synthesis is governed by two different mechanisms when the reaction temperature varies. At lower reaction temperatures ( 225 °C). For the CO 2 content of 5 vol.% and the pressure of 40 atm, the maximum DME yield is 1.89 g (g cat h) −1 . It is also found that 0.2 g of ZSM5 is sufficient to be blended with 1 g of the catalyst for DME synthesis.

  18. THE EFFECTIVE DIFFUSIVITY OF CLOVE(Eugenia caryophyllus ESSENTIAL OIL IN PRESSURIZED CO2

    Directory of Open Access Journals (Sweden)

    Caciano ZAPATA NOREÑA

    1997-12-01

    Full Text Available The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65 and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%.O coeficiente de difusão efetivo do óleo essencial de cravo-da-índia em CO2 líquido subcrítico foi estimado. O equipamento experimental usado foi um extrator de leito fixo. O leito fixo foi formado por cravo-da-índia moído (mesh -32 + 65 e compactado, sendo assim considerado como um meio sólido. O coeficiente de difusão efetivo foi estimado pelo ajuste do perfil de concentração experimental à equação de balanço de massa em estado transiente, para difusão unidirecional em um meio sólido. A dependência do coeficiente de difusão com a concentração de óleo no sólido, foi descrita por uma função exponencial. O coeficiente de difusão determinado variou de 3,64 a 5,22x10-10m2/s. Os erros médios relativos foram menores do que 3,1%.

  19. A multi-decade record of high-quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

    Science.gov (United States)

    Bakker, Dorothee; Landa, Camilla S.; Pfeil, Benjamin; Metzl, Nicolas; O’Brien, Kevin; Olsen, Are; Smith, Karl; Cosca, Cathy; Harasawa, Sumiko; Nakaoka, Shin-ichiro; Jones, Stephen; Nojiri, Yukihiro; Steinhoff, Tobias; Sweeney, Colm; Schuster, Ute; Takahashi, Taro; Tilbrook, Bronte; Wada, Chisato; Wanninkhof, Rik; Alin, Simone R.; Balestrini, Carlos F.; Barbero, Leticia; Bates, Nicholas; Bianchi, Alejandro A.; Bonou, Frédéric; Boutin, Jacqueline; Bozec, Yann; Burger, Eugene F.; Cai, Wei-Jun; Castle, Robert D.; Chen, Liqi; Chierici, Melissa; Currie, Kim; Evans, Wiley; Featherstone, Charles; Feely, Richard; Fransson, Agneta; Goyet, Catherine; Greenwood, Naomi; Gregor, Luke; Hankin, Steven C.; Hardman-Mountford, Nick J.; Harlay, Jérôme; Hauck, Judith; Hoppema, Mario; Humphreys, Matthew P.; Hunt, Christopher W.; Huss, Betty; Ibánhez, J. Severino P.; Johannessen, Truls; Keeling, Ralph F.; Kitidis, Vassilis; Körtzinger, Arne; Kozyr, Alex; Krasakopoulou, Evangelia; Kuwata, Akira; Landschützer, Peter; Lauvset, Siv K.; Lefèvre, Nathalie; Lo Monaco, Claire; Manke, Ansley; Mathis, Jeremy T.; Merlivat, Liliane; Millero, Frank J.; Monteiro, Pedro M. S.; Munro, David R.; Murata, Akihiko; Newberger, Timothy; Omar, Abdirahman M.; Ono, Tsuneo; Paterson, Kristina; Pearce, David; Pierrot, Denis; Robbins, Lisa L.; Saito, Shu; Salisbury, Joe; Schlitzer, Reiner; Schneider, Bernd; Schweitzer, Roland; Sieger, Rainer; Skjelvan, Ingunn; Sullivan, Kevin F.; Sutherland, Stewart C.; Sutton, Adrienne J.; Tadokoro, Kazuaki; Telszewski, Maciej; Tuma, Matthias; van Heuven, Steven M. A. C.; Vandemark, Douglas; Ward, Brian; Watson, Andrew J.; Xu, Suqing

    2016-01-01

    The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled f CO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million f CO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million f CO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water f CO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water f CO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) “living data” publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). 

  20. On the mechanism of high product selectivity for HCOOH using Pb in CO2 electroreduction.

    Science.gov (United States)

    Back, Seoin; Kim, Jun-Hyuk; Kim, Yong-Tae; Jung, Yousung

    2016-04-14

    While achieving high product selectivity is one of the major challenges of the CO2 electroreduction technology in general, Pb is one of the few examples with high selectivity that produces formic acid almost exclusively (versus H2, CO, or other byproducts). In this work, we study the mechanism of CO2 electroreduction reactions using Pb to understand the origin of high formic acid selectivity. In particular, we first assess the proton-assisted mechanism proposed in the literature using density functional calculations and find that it cannot fully explain the previous selectivity experiments for the Pb electrode. We then suggest an alternative proton-coupled-electron-transfer mechanism consistent with existing observations, and further validate a new mechanism by experimentally measuring and comparing the onset potentials for CO2 reduction vs. H2 production. We find that the origin of a high selectivity of the Pb catalyst for HCOOH production over CO and H2 lies in the strong O-affinitive and weak C-, H-affinitive characteristics of Pb, leading to the involvement of the *OCHO species as a key intermediate to produce HCOOH exclusively and preventing unwanted H2 production at the same time.

  1. Analysis of Pacific oyster larval proteome and its response to high-CO2

    KAUST Repository

    Dineshram, R.

    2012-10-01

    Most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-CO2 due to ocean acidification (OA) process. Analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool to examine these physiological symptoms at molecular level, but its applications are inadequate. To address this knowledge gap, 2-DE coupled with mass spectrophotometer was used to compare the global protein expression pattern of oyster larvae exposed to ambient and to high-CO2. Exposure to OA resulted in marked reduction of global protein expression with a decrease or loss of 71 proteins (18% of the expressed proteins in control), indicating a wide-spread depression of metabolic genes expression in larvae reared under OA. This is, to our knowledge, the first proteome analysis that provides insights into the link between physiological suppression and protein down-regulation under OA in oyster larvae. © 2012 Elsevier Ltd.

  2. Rapid and Accurate Machine Learning Recognition of High Performing Metal Organic Frameworks for CO2 Capture.

    Science.gov (United States)

    Fernandez, Michael; Boyd, Peter G; Daff, Thomas D; Aghaji, Mohammad Zein; Woo, Tom K

    2014-09-04

    In this work, we have developed quantitative structure-property relationship (QSPR) models using advanced machine learning algorithms that can rapidly and accurately recognize high-performing metal organic framework (MOF) materials for CO2 capture. More specifically, QSPR classifiers have been developed that can, in a fraction of a section, identify candidate MOFs with enhanced CO2 adsorption capacity (>1 mmol/g at 0.15 bar and >4 mmol/g at 1 bar). The models were tested on a large set of 292 050 MOFs that were not part of the training set. The QSPR classifier could recover 945 of the top 1000 MOFs in the test set while flagging only 10% of the whole library for compute intensive screening. Thus, using the machine learning classifiers as part of a high-throughput screening protocol would result in an order of magnitude reduction in compute time and allow intractably large structure libraries and search spaces to be screened.

  3. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser Y.; Ghanem, Bader; Alghunaimi, Fahd; Litwiller, Eric; Pinnau, Ingo

    2016-01-01

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  4. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser Y.

    2016-01-05

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  5. Hierarchical porous NiCo2O4 nanowires for high-rate supercapacitors.

    Science.gov (United States)

    Jiang, Hao; Ma, Jan; Li, Chunzhong

    2012-05-11

    We demonstrate a simple and scalable strategy for synthesizing hierarchical porous NiCo(2)O(4) nanowires which exhibit a high specific capacitance of 743 F g(-1) at 1 A g(-1) with excellent rate performance (78.6% capacity retention at 40 A g(-1)) and cycling stability (only 6.2% loss after 3000 cycles). This journal is © The Royal Society of Chemistry 2012

  6. High Efficiency Mask Based Laser Materials Processing with TEA-CO2 - and Excimer Laser

    DEFF Research Database (Denmark)

    Bastue, Jens; Olsen, Flemmming Ove

    1997-01-01

    In general, mask based laser materials processing techniques suffer from a very low energy efficiency. We have developed a simple device called an energy enhancer, which is capable of increasing the energy efficiency of typical mask based laser materials processing systems. A short review of the ...... line marking with TEA-CO2 laser of high speed canning lines. The second one is manufactured for marking or microdrilling with excimer laser....

  7. Observation of non-chemical equilibrium effect on Ar-CO2-H2 thermal plasma model by changing pressure

    International Nuclear Information System (INIS)

    Al-Mamun, Sharif Abdullah; Tanaka, Yasunori; Uesugi, Yoshihiko

    2009-01-01

    The authors developed a two-dimensional one-temperature chemical non-equilibrium (1T-NCE) model of Ar-CO 2 -H 2 inductively coupled thermal plasmas (ICTP) to investigate the effect of pressure variation. The basic concept of one-temperature model is the assumption and treatment of the same energy conservation equation for electrons and heavy particles. The energy conservation equations consider reaction heat effects and energy transfer among the species produced as well as enthalpy flow resulting from diffusion. Assuming twenty two (22) different particles in this model and by solving mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from hundred and ninety eight (198) chemical reactions, chemical non-equilibrium effects were taken into account. Transport and thermodynamic properties of Ar-CO 2 -H 2 thermal plasmas were self-consistently calculated using the first-order approximation of the Chapman-Enskog method. Finally results obtained at atmospheric pressure (760 Torr) and at reduced pressure (500, 300 Torr) were compared with results from one-temperature chemical equilibrium (1T-CE) model. And of course, this comparison supported discussion of chemical non-equilibrium effects in the inductively coupled thermal plasmas (ICTP).

  8. Design of compact dispersion interferometer with a high efficiency nonlinear crystal and a low power CO2 laser

    Science.gov (United States)

    Akiyama, T.; Yoshimura, S.; Tomita, K.; Shirai, N.; Murakami, T.; Urabe, K.

    2017-12-01

    When the electron density of a plasma generated in high pressure environment is measured by a conventional interferometer, the phase shifts due to changes of the neutral gas density cause significant measurement errors. A dispersion interferometer, which measures the phase shift that arises from dispersion of medium between the fundamental and the second harmonic wavelengths of laser light, can suppress the measured phase shift due to the variations of neutral gas density. In recent years, the CO2 laser dispersion interferometer has been applied to the atmospheric pressure plasmas and its feasibility has been demonstrated. By combining a low power laser and a high efficiency nonlinear crystal for the second harmonic component generation, a compact dispersion interferometer can be designed. The optical design and preliminary experiments are conducted.

  9. Surface Pressure Dependencies in the GEOS-Chem-Adjoint System and the Impact of the GEOS-5 Surface Pressure on CO2 Model Forecast

    Science.gov (United States)

    Lee, Meemong; Weidner, Richard

    2016-01-01

    In the GEOS-Chem Adjoint (GCA) system, the total (wet) surface pressure of the GEOS meteorology is employed as dry surface pressure, ignoring the presence of water vapor. The Jet Propulsion Laboratory (JPL) Carbon Monitoring System (CMS) research team has been evaluating the impact of the above discrepancy on the CO2 model forecast and the CO2 flux inversion. The JPL CMS research utilizes a multi-mission assimilation framework developed by the Multi-Mission Observation Operator (M2O2) research team at JPL extending the GCA system. The GCA-M2O2 framework facilitates mission-generic 3D and 4D-variational assimilations streamlining the interfaces to the satellite data products and prior emission inventories. The GCA-M2O2 framework currently integrates the GCA system version 35h and provides a dry surface pressure setup to allow the CO2 model forecast to be performed with the GEOS-5 surface pressure directly or after converting it to dry surface pressure.

  10. Net Ecosystem Exchange of CO2 with Rapidly Changing High Arctic Landscapes

    Science.gov (United States)

    Emmerton, C. A.

    2015-12-01

    High Arctic landscapes are expansive and changing rapidly. However our understanding of their functional responses and potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements to quantify the net ecosystem exchange (NEE) of CO2 with polar semidesert and meadow wetland landscapes at the highest-latitude location measured to date (82°N). We coupled these rare data with ground and satellite vegetation production measurements (Normalized Difference Vegetation Index; NDVI) to evaluate the effectiveness of upscaling local to regional NEE. During the growing season, the dry polar semidesert landscape was a near zero sink of atmospheric CO2 (NEE: -0.3±13.5 g C m-2). A nearby meadow wetland accumulated over two magnitudes more carbon (NEE: -79.3±20.0 g C m-2) than the polar semidesert landscape, and was similar to meadow wetland NEE at much more southern latitudes. Polar semidesert NEE was most influenced by moisture, with wetter surface soils resulting in greater soil respiration and CO2 emissions. At the meadow wetland, soil heating enhanced plant growth, which in turn increased CO2 uptake. Our upscaling assessment found that polar semidesert NDVI measured on site was low (mean: 0.120-0.157) and similar to satellite measurements (mean: 0.155-0.163). However, weak plant growth resulted in poor satellite NDVI-NEE relationships and created challenges for remotely-detecting changes in the cycling of carbon on the polar semidesert landscape. The meadow wetland appeared more suitable to assess plant production and NEE via remote-sensing, however high Arctic wetland extent is constrained by topography to small areas that may be difficult to resolve with large satellite pixels. We predict that until summer precipitation and humidity increases substantially, climate-related changes of dry high Arctic landscapes may be restricted by poor soil moisture retention, and therefore have some inertia against

  11. CaO-based CO2 sorbents: from fundamentals to the development of new, highly effective materials.

    Science.gov (United States)

    Kierzkowska, Agnieszka M; Pacciani, Roberta; Müller, Christoph R

    2013-07-01

    The enormous anthropogenic emission of the greenhouse gas CO2 is most likely the main reason for climate change. Considering the continuing and indeed growing utilisation of fossil fuels for electricity generation and transportation purposes, development and implementation of processes that avoid the associated emissions of CO2 are urgently needed. CO2 capture and storage, commonly termed CCS, would be a possible mid-term solution to reduce the emissions of CO2 into the atmosphere. However, the costs associated with the currently available CO2 capture technology, that is, amine scrubbing, are prohibitively high, thus making the development of new CO2 sorbents a highly important research challenge. Indeed, CaO, readily obtained through the calcination of naturally occurring limestone, has been proposed as an alternative CO2 sorbent that could substantially reduce the costs of CO2 capture. However, one of the major drawbacks of using CaO derived from natural sources is its rapidly decreasing CO2 uptake capacity with repeated carbonation-calcination reactions. Here, we review the current understanding of fundamental aspects of the cyclic carbonation-calcination reactions of CaO such as its reversibility and kinetics. Subsequently, recent attempts to develop synthetic, CaO-based sorbents that possess high and cyclically stable CO2 uptakes are presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  13. High Blood Pressure Facts

    Science.gov (United States)

    ... Stroke Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir On ... Top of Page CDC Fact Sheets Related to High Blood Pressure High Blood Pressure Pulmonary Hypertension Heart Disease Signs ...

  14. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  15. Diffusion-cooled high-power single-mode waveguide CO2 laser for transmyocardial revascularization

    Science.gov (United States)

    Berishvili, I. I.; Bockeria, L. A.; Egorov, E. N.; Golubev, Vladimir S.; Galushkin, Michail G.; Kheliminsky, A. A.; Panchenko, Vladislav Y.; Roshin, A. P.; Sigaev, I. Y.; Vachromeeva, M. N.; Vasiltsov, Victor V.; Yoshina, V. I.; Zabelin, Alexandre M.; Zelenov, Evgenii V.

    1999-01-01

    The paper presents the results on investigations and development of multichannel waveguide CO2 laser with diffusion cooling of active medium excited by discharge of audio-frequency alternating current. The description of high-power single-mode CO2 laser with average beam power up to 1 kW is presented. The result of measurement of the laser basic parameters are offered, as well as the outcomes of performances of the laser head with long active zone, operating in waveguide mode. As an example of application of these laser, various capabilities a description of the developed medical system 'Genom' used in the transmyocardial laser revascularization (TMLR) procedure and clinical results of the possibilities of the TMLR in the surgical treatment are presented.

  16. Development of high-power CO2 lasers and laser material processing

    Science.gov (United States)

    Nath, Ashish K.; Choudhary, Praveen; Kumar, Manoj; Kaul, R.

    2000-02-01

    Scaling laws to determine the physical dimensions of the active medium and optical resonator parameters for designing convective cooled CO2 lasers have been established. High power CW CO2 lasers upto 5 kW output power and a high repetition rate TEA CO2 laser of 500 Hz and 500 W average power incorporated with a novel scheme for uniform UV pre- ionization have been developed for material processing applications. Technical viability of laser processing of several engineering components, for example laser surface hardening of fine teeth of files, laser welding of martensitic steel shroud and titanium alloy under-strap of turbine, laser cladding of Ni super-alloy with stellite for refurbishing turbine blades were established using these lasers. Laser alloying of pre-placed SiC coating on different types of aluminum alloy, commercially pure titanium and Ti-6Al-4V alloy, and laser curing of thermosetting powder coating have been also studied. Development of these lasers and results of some of the processing studies are briefly presented here.

  17. High temperature capture of CO2 on lithium-based sorbents from rice husk ash.

    Science.gov (United States)

    Wang, Ke; Guo, Xin; Zhao, Pengfei; Wang, Fanzi; Zheng, Chuguang

    2011-05-15

    Highly efficient Li(4)SiO(4) (lithium orthosilicate)-based sorbents for CO(2) capture at high temperature, was developed using waste materials (rice husk ash). Two treated rice husk ash (RHA) samples (RHA1 and RHA2) were prepared and calcined at 800°C in the presence of Li(2)CO(3). Pure Li(4)SiO(4) and RHA-based sorbents were characterized by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetry. CO(2) sorption was tested through 15 carbonation/calcination cycles in a fixed bed reactor. The metals of RHA were doped with Li(4)SiO(4) resulting to inhibited growth of the particles and increased pore volume and surface area. Thermal analyses indicated a much better CO(2) absorption in Li(4)SiO(4)-based sorbent prepared from RHA1 (higher metal content sample) because the activation energies for the chemisorption process and diffusion process were smaller than that of pure Li(4)SiO(4). RHA1-based sorbent also maintained higher capacities during the multiple cycles. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Species Interactions Drive Fish Biodiversity Loss in a High-CO2 World.

    Science.gov (United States)

    Nagelkerken, Ivan; Goldenberg, Silvan U; Ferreira, Camilo M; Russell, Bayden D; Connell, Sean D

    2017-07-24

    Accelerating climate change is eroding the functioning and stability of ecosystems by weakening the interactions among species that stabilize biological communities against change [1]. A key challenge to forecasting the future of ecosystems centers on how to extrapolate results from short-term, single-species studies to community-level responses that are mediated by key mechanisms such as competition, resource availability (bottom-up control), and predation (top-down control) [2]. We used CO 2 vents as potential analogs of ocean acidification combined with in situ experiments to test current predictions of fish biodiversity loss and community change due to elevated CO 2 [3] and to elucidate the potential mechanisms that drive such change. We show that high risk-taking behavior and competitive strength, combined with resource enrichment and collapse of predator populations, fostered already common species, enabling them to double their populations under acidified conditions. However, the release of these competitive dominants from predator control led to suppression of less common and subordinate competitors that did not benefit from resource enrichment and reduced predation. As a result, local biodiversity was lost and novel fish community compositions were created under elevated CO 2 . Our study identifies the species interactions most affected by ocean acidification, revealing potential sources of natural selection. We also reveal how diminished predator abundances can have cascading effects on local species diversity, mediated by complex species interactions. Reduced overfishing of predators could therefore act as a key action to stall diversity loss and ecosystem change in a high-CO 2 world. VIDEO ABSTRACT. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The fate of the Greenland Ice Sheet in a geoengineered, high CO2 world

    International Nuclear Information System (INIS)

    Irvine, Peter J; Lunt, Daniel J; Stone, Emma J; Ridgwell, Andy

    2009-01-01

    Solar radiation management (SRM) geoengineering has been proposed as one means of helping avoid the occurrence of dangerous climate change and undesirable state transitions ('tipping points') in the Earth system. The irreversible melting of the Greenland Ice Sheet is a case in point-a state transition that could occur as a result of CO 2 -driven elevated global temperatures, and one leading to potentially catastrophic sea-level rise. SRM schemes such as the creation of a 'sunshade' or injection of sulfate aerosols into the stratosphere could reduce incoming solar radiation, and in theory balance, in a global mean, the greenhouse warming resulting from elevated concentrations of CO 2 in the atmosphere. Previous work has highlighted that a geoengineered world would have: warming towards the poles, cooling in the tropics, and a reduction in the global hydrological cycle, which may have important implications for the Greenland Ice Sheet. Using a fully coupled global climate model in conjunction with an ice sheet model, we assess the consequences for the mass balance of the Greenland Ice Sheet of the reorganization of climate patterns by the combination of high CO 2 and geoengineering. We find that Greenland surface temperature and precipitation anomalies, compared to the pre-industrial situation, decrease almost linearly with increasing levels of SRM geoengineering, but that these combine to create a highly non-linear response of the ice sheet. The substantial melting of the Greenland Ice Sheet predicted for four times pre-industrial CO 2 levels is prevented in our model with only a partial application of SRM, and hence without having to fully restore the global average temperature back to pre-industrial levels. This suggests that the degree of SRM geoengineering required to mitigate the worst impacts of greenhouse warming, such as sea-level rise, need not be as extensive as generally assumed.

  20. A Thermodynamic Approach for Modeling H2O-CO2 Solubility in Alkali-rich Mafic Magmas at Mid-crustal Pressures

    Science.gov (United States)

    Allison, C. M.; Roggensack, K.; Clarke, A. B.

    2017-12-01

    Volatile solubility in magmas is dependent on several factors, including composition and pressure. Mafic (basaltic) magmas with high concentrations of alkali elements (Na and K) are capable of dissolving larger quantities of H2O and CO2 than low-alkali basalt. The exsolution of abundant gases dissolved in alkali-rich mafic magmas can contribute to large explosive eruptions. Existing volatile solubility models for alkali-rich mafic magmas are well calibrated below 200 MPa, but at greater pressures the experimental data is sparse. To allow for accurate interpretation of mafic magmatic systems at higher pressures, we conducted a set of mixed H2O-CO2 volatile solubility experiments between 400 and 600 MPa at 1200 °C in six mafic compositions with variable alkali contents. Compositions include magmas from volcanoes in Italy, Antarctica, and Arizona. Results from our experiments indicate that existing volatile solubility models for alkali-rich mafic magmas, if extrapolated beyond their calibrated range, over-predict CO2 solubility at mid-crustal pressures. Physically, these results suggest that volatile exsolution can occur at deeper levels than what can be resolved from the lower-pressure experimental data. Existing thermodynamic models used to calculate volatile solubility at different pressures require two experimentally derived parameters. These parameters represent the partial molar volume of the condensed volatile species in the melt and its equilibrium constant, both calculated at a standard temperature and pressure. We derived these parameters for each studied composition and the corresponding thermodynamic model shows good agreement with the CO2 solubility data of the experiments. A general alkali basalt solubility model was also constructed by establishing a relationship between magma composition and the thermodynamic parameters. We utilize cation fractions from our six compositions along with four compositions from the experimental literature in a linear

  1. Pressure Build-up and Decay in Acid Gas Injection Operations in Reefs in the Zama Field, Canada, and Implications for CO2 Storage

    International Nuclear Information System (INIS)

    Pooladi-Darvish, M.; Hong, H.; Pooladi-Darvish, M.; Bachu, S.

    2011-01-01

    The objective of this paper is to examine reasons for pressure rise in the Zama X2X pool in northwestern Alberta, Canada, that was used for acid gas disposal, and whether subsequent pressure decay was a result of pressure dissipation into a larger aquifer. The Zama X2X pool, approximately 1 km 2 in size, is connected to four other nearby pools through a common underlying aquifer. Pressure analysis for all the pools indicates that they are in good hydraulic communication. Initial pressure in the Zama X2X pool was approximately 15 MPa. Pressure declined first during oil production, stabilizing at around 10 MPa in the early 1970's, after which started to increase such that it reached 26 MPa in 1986. Subsequently, pressure declined reaching 22 MPa by 1995 just prior to starting injection of acid gas (80% CO 2 and 20% H 2 S). The operator injected acid gas at lower rates and wellhead pressures than those licensed by the regulatory agency. Despite significant production of water and hydrocarbons, the pressure in the Zama X2X pool continued to be higher than the initial reservoir pressure by more than 5 MPa, such that disposal operations were suspended in late 1998. Oil production continued all this time until 2002. Numerical simulations using CMG-IMEM and corresponding sensitivity studies reported in this paper show that disposal of more than 1 million m 3 of water between 1970 and 1988 and again in 1992-1993 in the adjacent Zama YY pool, which is in good hydrodynamic communication with the Zama X2X pool through the aquifer below the oil column, is the main reason for the high pressures observed in the Zama X2X pool. Sensitivity studies indicate that pressure decay in the X2X pool was due to fluid production. The study indicates that while pressure rise has been caused by hydraulic communication between the X2X and YY pools through the common aquifer, the aquifer was not of large volume to allow dissipation of the pressure. In addition to the case study, the implications

  2. A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

    KAUST Repository

    Li, Peng

    2014-11-13

    Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

  3. A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

    KAUST Repository

    Li, Peng; He, Yabing; Zhao, Yunfeng; Weng, Linhong; Wang, Hailong; Krishna, Rajamani A A; Wu, Hui; Zhou, Wei; O'Keeffe, Michael A.; Han, Yu; Chen, Banglin

    2014-01-01

    Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

  4. Effect of Suction Nozzle Pressure Drop on the Performance of an Ejector-Expansion Transcritical CO2 Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-08-01

    Full Text Available The basic transcritical CO2 systems exhibit low energy efficiency due to their large throttling loss. Replacing the throttle valve with an ejector is an effective measure for recovering some of the energy lost in the expansion process. In this paper, a thermodynamic model of the ejector-expansion transcritical CO2 refrigeration cycle is developed. The effect of the suction nozzle pressure drop (SNPD on the cycle performance is discussed. The results indicate that the SNPD has little impact on entrainment ratio. There exists an optimum SNPD which gives a maximum recovered pressure and COP under a specified condition. The value of the optimum SNPD mainly depends on the efficiencies of the motive nozzle and the suction nozzle, but it is essentially independent of evaporating temperature and gas cooler outlet temperature. Through optimizing the value of SNPD, the maximum COP of the ejector-expansion cycle can be up to 45.1% higher than that of the basic cycle. The exergy loss of the ejector-expansion cycle is reduced about 43.0% compared with the basic cycle.

  5. Dissemination of bacteria labeled with technetium-99m after laparotomy and abdominal insufflation with different CO2 pressures on rats

    International Nuclear Information System (INIS)

    Pitombo, Marcos Bettini; Faria, Clarice Abreu dos Santos Albuquerque de; Steinbruck, Klaus; Bernardo, Luciana Camargo; Bernardo Filho, Mario

    2008-01-01

    Purpose: To asses the dissemination of bacteria labeled with technetium-99m (99mTc) from peritoneal cavity after different surgical procedures. Methods: Bacteria of the Escherichia coli species labeled with 99mTc were used in a concentration of 108 units of colony-makers for ml (UFC/ml) and 1 ml was inoculated through intra-peritoneal via. Forty-eight rats were divided into four groups: control, laparotomy, pneumoperitoneum with 10 mmHg and pneumoperitoneum with 20 mmHg of CO2. Procedures were performed 20 min after injection of the inoculum and lasted 30 min. Animals were sacrificed after six hours (Group 1) and 24 hours (Group 2). Samples of blood, liver and spleen were collected for radioactivity counting. Results: After six hours, indirect detection of the bacteria in different organs was uniform in all groups. After 24 hours, a larger detection of technetium was observed in the livers of animals of the group insufflated with 20 mmHg of CO2, when compared with those of control group (p<0.01). The other groups did not present statistically significant variations. Conclusions: The use of a higher intra-abdominal pressure was associated with a higher bacterial dissemination to the liver. The application of lower intra-abdominal pressures may be associated with a lower dissemination of the infectious status during laparoscopic approach of peritonitis status. (author)

  6. A Heat Transfer Correlation in a Vertical Upward Flow of CO2 at Supercritical Pressures

    International Nuclear Information System (INIS)

    Kim, Hyung Rae; Bae, Yoon Yeong; Song, Jin Ho; Kim, Hwan Yeol

    2006-01-01

    Heat transfer data has been collected in the heat transfer test loop, named SPHINX (Supercritical Pressure Heat Transfer Investigation for NeXt generation), in KAERI. The facility primarily aims at the generation of heat transfer data in the flow conditions and geometries relevant to SCWR (SuperCritical Water-cooled Reactor). The produced data will aid the thermohydraulic design of a reactor core. The loop uses carbon dioxide, and later the results will be scaled to the water flows. The heat transfer data has been collected for a vertical upward flow in a circular tube with varying mass fluxes, heat fluxes, and operating pressures. The results are compared with the existing correlations and a new correlation is proposed by fine-tuning the one of the existing correlations

  7. Granular bamboo-derived activated carbon for high CO(2) adsorption: the dominant role of narrow micropores.

    Science.gov (United States)

    Wei, Haoran; Deng, Shubo; Hu, Bingyin; Chen, Zhenhe; Wang, Bin; Huang, Jun; Yu, Gang

    2012-12-01

    Cost-effective biomass-derived activated carbons with a high CO(2) adsorption capacity are attractive for carbon capture. Bamboo was found to be a suitable precursor for activated carbon preparation through KOH activation. The bamboo size in the range of 10-200 mesh had little effect on CO(2) adsorption, whereas the KOH/C mass ratio and activation temperature had a significant impact on CO(2) adsorption. The bamboo-derived activated carbon had a high adsorption capacity and excellent selectivity for CO(2) , and also the adsorption process was highly reversible. The adsorbed amount of CO(2) on the granular activated carbon was up to 7.0 mmol g(-1) at 273 K and 1 bar, which was higher than almost all carbon materials. The pore characteristics of activated carbons responsible for high CO(2) adsorption were fully investigated. Based on the analysis of narrow micropore size distribution of several activated carbons prepared under different conditions, a more accurate micropore range contributing to CO(2) adsorption was proposed. The volume of micropores in the range of 0.33-0.82 nm had a good linear relationship with CO(2) adsorption at 273 K and 1 bar, and the narrow micropores of about 0.55 nm produced the major contribution, which could be used to evaluate CO(2) adsorption on activated carbons. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Highly efficient photochemical HCOOH production from CO2 and water using an inorganic system

    Directory of Open Access Journals (Sweden)

    Satoshi Yotsuhashi

    2012-12-01

    Full Text Available We have constructed a system that uses solar energy to react CO2 with water to generate formic acid (HCOOH at an energy conversion efficiency of 0.15%. It consists of an AlGaN/GaN anode photoelectrode and indium (In cathode that are electrically connected outside of the reactor cell. High energy conversion efficiency is realized due to a high quantum efficiency of 28% at 300 nm, attributable to efficient electron-hole separation in the semiconductor's heterostructure. The efficiency is close to that of natural photosynthesis in plants, and what is more, the reaction product (HCOOH can be used as a renewable energy source.

  9. High-performance modeling of CO2 sequestration by coupling reservoir simulation and molecular dynamics

    KAUST Repository

    Bao, Kai

    2013-01-01

    The present work describes a parallel computational framework for CO2 sequestration simulation by coupling reservoir simulation and molecular dynamics (MD) on massively parallel HPC systems. In this framework, a parallel reservoir simulator, Reservoir Simulation Toolbox (RST), solves the flow and transport equations that describe the subsurface flow behavior, while the molecular dynamics simulations are performed to provide the required physical parameters. Numerous technologies from different fields are employed to make this novel coupled system work efficiently. One of the major applications of the framework is the modeling of large scale CO2 sequestration for long-term storage in the subsurface geological formations, such as depleted reservoirs and deep saline aquifers, which has been proposed as one of the most attractive and practical solutions to reduce the CO2 emission problem to address the global-warming threat. To effectively solve such problems, fine grids and accurate prediction of the properties of fluid mixtures are essential for accuracy. In this work, the CO2 sequestration is presented as our first example to couple the reservoir simulation and molecular dynamics, while the framework can be extended naturally to the full multiphase multicomponent compositional flow simulation to handle more complicated physical process in the future. Accuracy and scalability analysis are performed on an IBM BlueGene/P and on an IBM BlueGene/Q, the latest IBM supercomputer. Results show good accuracy of our MD simulations compared with published data, and good scalability are observed with the massively parallel HPC systems. The performance and capacity of the proposed framework are well demonstrated with several experiments with hundreds of millions to a billion cells. To our best knowledge, the work represents the first attempt to couple the reservoir simulation and molecular simulation for large scale modeling. Due to the complexity of the subsurface systems

  10. Effects of high CO2 seawater on the copepod (Acartia tsuensis) through all life stages and subsequent generations

    International Nuclear Information System (INIS)

    Kurihara, Haruko; Ishimatsu, Atsushi

    2008-01-01

    We studied the effects of exposure to seawater equilibrated with CO 2 -enriched air (CO 2 2380 ppm) from eggs to maturity and over two subsequent generations on the copepod Acartia tsuensis. Compared to the control (CO 2 380 ppm), high CO 2 exposure through all life stages of the 1st generation copepods did not significantly affect survival, body size or developmental speed. Egg production and hatching rates were also not significantly different between the initial generation of females exposed to high CO 2 and the 1st and 2nd generation females developed from eggs to maturity in high CO 2 . Thus, the copepods appear more tolerant to increased CO 2 than other marine organisms previously investigated for CO 2 tolerance (i.e., sea urchins and bivalves). However, the crucial importance of copepods in marine ecosystems requires thorough evaluation of the overall impacts of marine environmental changes predicted to occur with increased CO 2 concentrations, i.e., increased temperature, enhanced UV irradiation, and changes in the community structure and nutritional value of phytoplankton

  11. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2 : an experiment with plant populations from naturally high CO2 areas

    NARCIS (Netherlands)

    van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may

  12. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Teens / Hypertension (High Blood Pressure) What's ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  13. Highly Rechargeable Lithium-CO2 Batteries with a Boron- and Nitrogen-Codoped Holey-Graphene Cathode.

    Science.gov (United States)

    Qie, Long; Lin, Yi; Connell, John W; Xu, Jiantie; Dai, Liming

    2017-06-06

    Metal-air batteries, especially Li-air batteries, have attracted significant research attention in the past decade. However, the electrochemical reactions between CO 2 (0.04 % in ambient air) with Li anode may lead to the irreversible formation of insulating Li 2 CO 3 , making the battery less rechargeable. To make the Li-CO 2 batteries usable under ambient conditions, it is critical to develop highly efficient catalysts for the CO 2 reduction and evolution reactions and investigate the electrochemical behavior of Li-CO 2 batteries. Here, we demonstrate a rechargeable Li-CO 2 battery with a high reversibility by using B,N-codoped holey graphene as a highly efficient catalyst for CO 2 reduction and evolution reactions. Benefiting from the unique porous holey nanostructure and high catalytic activity of the cathode, the as-prepared Li-CO 2 batteries exhibit high reversibility, low polarization, excellent rate performance, and superior long-term cycling stability over 200 cycles at a high current density of 1.0 A g -1 . Our results open up new possibilities for the development of long-term Li-air batteries reusable under ambient conditions, and the utilization and storage of CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Investigation of a high power UV pre-ionized tea CO2 laser for making purposes

    International Nuclear Information System (INIS)

    Tan Shiw Jin; Low Kum Seng

    1988-01-01

    A simple, high-power TEA CO 2 laser using profiled electrodes with capacitatively-coupled side-arcs to provide preionization is described. The output pulse energy, beam size and beam divergence of this laser is measured as well as the voltage across the two laser electrodes. The effect of various operating parameters on the output pulse energy and efficiency of this laser are also described. The laser, with a maximum output energy of 4 J per pulse, has been used successfully to mark plastic surfaces such as plastic Ic components. (author)

  15. Design of an Optical System for High Power CO2 Laser Cutting

    DEFF Research Database (Denmark)

    de Lange, D.F.; Meijer, J.; Nielsen, Jakob Skov

    2003-01-01

    The results of a design study for the optical system for cutting with high power CO2 lasers (6 kW and up) will be presented. As transparent materials cannot be used for these power levels, mirrors have been applied. A coaxial cutting gas supply has been designed with a laser beam entrance into th...... independent of the entering beam angle or position. manufacturing tolerances have been compensated in a one time adjustment during the assembly of the optical system. Preliminary cutting results in 13 mm thick steel in a shipyard application show a signinficant improvement in the cutting performance....

  16. Effect of CH4 on the CO2 breakthrough pressure and permeability of partially saturated low-permeability sandstone in the Ordos Basin, China

    Science.gov (United States)

    Zhao, Yan; Yu, Qingchun

    2018-01-01

    The behavior of CO2 that coexists with CH4 and the effect of CH4 on the CO2 stream need to be deeply analyzed and studied, especially in the presence of water. Our previous studies investigated the breakthrough pressure and permeability of pure CO2 in five partially saturated low-permeability sandstone core samples from the Ordos Basin, and we concluded that rocks with a small pore size and low permeability show considerable sealing capacity even under unsaturated conditions. In this paper, we selected three of these samples for CO2-CH4 gas-mixture breakthrough experiments under various degrees of water saturation. The breakthrough experiments were performed by increasing the gas pressure step by step until breakthrough occurred. Then, the effluent gas mixture was collected for chromatographic partitioning analysis. The results indicate that CH4 significantly affects the breakthrough pressure and permeability of CO2. The presence of CH4 in the gas mixture increases the interfacial tension and, thus, the breakthrough pressure. Therefore, the injected gas mixture that contains the highest (lowest) mole fraction of CH4 results in the largest (smallest) breakthrough pressure. The permeability of the gas mixture is greater than that for pure CO2 because of CH4, and the effective permeability decreases with increased breakthrough pressure. Chromatographic partitioning of the effluent mixture gases indicates that CH4 breaks through ahead of CO2 as a result of its weaker solubility in water. Correlations are established between (1) the breakthrough pressure and water saturation, (2) the effective permeability and water saturation, (3) the breakthrough pressure and effective permeability, and (4) the mole fraction of CO2/CH4 in the effluent mixture gases and water saturation. These results deepen our understanding of the multi-phase flow behavior in the porous media under unsaturated conditions, which have implications for formulating emergency response plans for gas

  17. NiCo2O4 particles with diamond-shaped hexahedron structure for high-performance supercapacitors

    Science.gov (United States)

    Li, Yanfang; Hou, Xiaojuan; Zhang, Zengxing; Hai, Zhenyin; Xu, Hongyan; Cui, Danfeng; Zhuiykov, Serge; Xue, Chenyang

    2018-04-01

    Nickel cobalt oxide (NiCo2O4) particles with a diamond-shaped hexahedral porous sheet structure are successfully synthesized by a facile hydrothermal method, followed by calcination in one step. NiCo2O4-I and NiCo2O4-II particles are prepared using the same method with different contents of urea (CO(NH2)2) and ammonium fluoride (NH4F). The different morphologies of the NiCo2O4-I and NiCo2O4-II particles illustrate that CO(NH2)2 and NH4F play an important role in crystal growth. To verify the influence of NH4F and CO(NH2)2 on the morphology of the NiCo2O4 particles, the theory of crystal growth morphology is analyzed. The electrochemical measurements show that NiCo2O4 particles exhibit a high specific capacitance. At a current density of 1.0 mA cm-2, the mass specific capacitances of the NiCo2O4-I and NiCo2O4-II electrodes are 690.75 and 1710.9 F g-1, respectively, in a 6 M KOH aqueous electrolyte. The specific capacitances of the NiCo2O4-I and NiCo2O4-II electrodes remain ∼95.95% and ∼70.58% of the initial capacitance values after 5000 cycles, respectively. According to the two-electrode test, the NiCo2O4-II//AC asymmetric electrodes exhibited an ultrahigh energy density of 64.67 Wh kg-1 at the power density of 12 kW kg-1, demonstrating its excellent application potential as an electrode material for supercapacitors.

  18. End tidal-to-arterial CO2 and O2 gas gradients at low- and high-altitude during dynamic end-tidal forcing.

    Science.gov (United States)

    Tymko, Michael M; Ainslie, Philip N; MacLeod, David B; Willie, Chris K; Foster, Glen E

    2015-06-01

    We sought to characterize and quantify the performance of a portable dynamic end-tidal forcing (DEF) system in controlling the partial pressure of arterial CO2 (Pa(CO2)) and O2 (Pa(O2)) at low (LA; 344 m) and high altitude (HA; 5,050 m) during an isooxic CO2 test and an isocapnic O2 test, which is commonly used to measure ventilatory and vascular reactivity in humans (n = 9). The isooxic CO2 tests involved step changes in the partial pressure of end-tidal CO2 (PET(CO2)) of -10, -5, 0, +5, and +10 mmHg from baseline. The isocapnic O2 test consisted of a 10-min hypoxic step (PET(O2) = 47 mmHg) from baseline at LA and a 5-min euoxic step (PET(O2) = 100 mmHg) from baseline at HA. At both altitudes, PET(O2) and PET(CO2) were controlled within narrow limits (<1 mmHg from target) during each protocol. During the isooxic CO2 test at LA, PET(CO2) consistently overestimated Pa(CO2) (P < 0.01) at both baseline (2.1 ± 0.5 mmHg) and hypercapnia (+5 mmHg: 2.1 ± 0.7 mmHg; +10 mmHg: 1.9 ± 0.5 mmHg). This P(a)-PET(CO2) gradient was approximately twofold greater at HA (P < 0.05). At baseline at both altitudes, PET(O2) overestimated Pa(O2) by a similar extent (LA: 6.9 ± 2.1 mmHg; HA: 4.5 ± 0.9 mmHg; both P < 0.001). This overestimation persisted during isocapnic hypoxia at LA (6.9 ± 0.6 mmHg) and during isocapnic euoxia at HA (3.8 ± 1.2 mmHg). Step-wise multiple regression analysis, on the basis of the collected data, revealed that it may be possible to predict an individual's arterial blood gases during DEF. Future research is needed to validate these prediction algorithms and determine the implications of end-tidal-to-arterial gradients in the assessment of ventilatory and/or vascular reactivity. Copyright © 2015 the American Physiological Society.

  19. Amine-Functionalized Amino Acid-based Ionic Liquids as Efficient and High-Capacity Absorbents for CO2

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Kunov-Kruse, Andreas Jonas; Fehrmann, Rasmus

    2014-01-01

    Ionic liquids (ILs) comprised of ammonium cations and anions of naturally occurring amino acids containing an additional amine group (e.g., lysine, histidine, asparagine, and glutamine) were examined as high-capacity absorbents for CO2. An absorption capacity of 2.1 mol CO2 per mol of IL (3.5 mol...

  20. High repetition ration solid state switched CO2 TEA laser employed in industrial ultrasonic testing of aircraft parts

    Science.gov (United States)

    von Bergmann, Hubertus; Morkel, Francois; Stehmann, Timo

    2015-02-01

    Laser Ultrasonic Testing (UT) is an important technique for the non-destructive inspection of composite parts in the aerospace industry. In laser UT a high power, short pulse probe laser is scanned across the material surface, generating ultrasound waves which can be detected by a second low power laser system and are used to draw a defect map of the part. We report on the design and testing of a transversely excited atmospheric pressure (TEA) CO2 laser system specifically optimised for laser UT. The laser is excited by a novel solid-state switched pulsing system and utilises either spark or corona preionisation. It provides short output pulses of less than 100 ns at repetition rates of up to 1 kHz, optimised for efficient ultrasonic wave generation. The system has been designed for highly reliable operation under industrial conditions and a long term test with total pulse counts in excess of 5 billion laser pulses is reported.

  1. High-temperature resistivity and thermoelectric properties of coupled substituted Ca3Co2O6

    Directory of Open Access Journals (Sweden)

    Meenakshisundaram Senthilkumar and Rajagopalan Vijayaraghavan

    2009-01-01

    Full Text Available Polycrystalline samples of Ca3−xNaxCo2−xMnxO6 (x=0.0–0.5 have been prepared by the sol-gel cum combustion method using sucrose in order to investigate the effects of the coupled substitution of Na and Mn on Ca and Co sites on the transport properties of Ca3Co2O6(Co326. The products were characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction (XRD, thermogravimetry (TGA, differential thermal analysis and scanning electron microscopy. XRD patterns reveal the formation of single-phase products up to x=0.5. Coupled substitution increases the solubility of both Na and Mn on Ca and Co sites, respectively, in contrast to the limited solubility of Na and Mn (x=0.2 when separately substituted. TGA confirms the formation of the Ca3Co2O6 phase at temperatures ~720 °C. The grain size of the parent and substituted products is in the range 150–250 nm. Electrical resistivity and Seebeck coefficient were measured in the temperature range 300–800 K. Resistivity shows semiconducting behavior for all the compositions, particularly in the low-temperature regime. The Seebeck coefficient increases with temperature throughout the measured temperature range for all compositions. The maximum Seebeck coefficient (200 μV K−1 is observed for x=0.5 at 825 K, and this composition may be optimal for high-temperature thermoelectric applications.

  2. Highly Stable Porous Covalent Triazine-Piperazine Linked Nanoflower as a Feasible Adsorbent for Flue Gas CO2 Capture

    KAUST Repository

    Das, Swapan Kumar

    2016-02-11

    Here, we report a porous covalent triazine-piperazine linked polymer (CTPP) featuring 3D nanoflower morphology and enhanced capture/removal of CO2, CH4 from air (N2), essential to control greenhouse gas emission and natural gas upgrading. 13C solid-state NMR and FTIR analyses and CHN and X-ray photoelectron spectroscopy (XPS) elemental analyses confirmed the integration of triazine and piperazine components in the network. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) analyses revealed a relatively uniform particle size of approximately 400 to 500 nm with 3D nanoflower microstructure, which was formed by the self-assembly of interwoven and slight bent nanoflake components. The material exhibited outstanding chemical robustness under acidic and basic medium and high thermal stability up to 773 K. The CTPP possess high surface area (779 m2/g) and single-component gas adsorption study exhibited enhanced CO2 and CH4 uptake of 3.48 mmol/g, 1.09 mmol/g, respectively at 273 K, 1 bar; coupled with high sorption selectivities for CO2/N2 and CH4/N2 of 128 and 17, respectively. The enriched Lewis basicity of the CTPP favors the interaction with CO2, which results in an enhanced CO2 adsorption capacity and high CO2/N2 selectivity. The binary mixture breakthrough study for the flue gas composition at 298 K showed a high CO2/N2 selectivity of 82. CO2 heats of adsorption for the CTPP (34 kJ mol−1) were realized at the borderline between strong physisorption and weak chemisorption (QstCO2; 25−50 kJ mol−1) and low Qst value for N2 (22.09 kJ mol−1), providing the ultimate validation for the high selectivity of CO2 over N2.

  3. Trajectory study of supercollision relaxation in highly vibrationally excited pyrazine and CO2.

    Science.gov (United States)

    Li, Ziman; Sansom, Rebecca; Bonella, Sara; Coker, David F; Mullin, Amy S

    2005-09-01

    Classical trajectory calculations were performed to simulate state-resolved energy transfer experiments of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) and CO(2), which were conducted using a high-resolution transient infrared absorption spectrometer. The goal here is to use classical trajectories to simulate the supercollision energy transfer pathway wherein large amounts of energy are transferred in single collisions in order to compare with experimental results. In the trajectory calculations, Newton's laws of motion are used for the molecular motion, isolated molecules are treated as collections of harmonic oscillators, and intermolecular potentials are formed by pairwise Lennard-Jones potentials. The calculations qualitatively reproduce the observed energy partitioning in the scattered CO(2) molecules and show that the relative partitioning between bath rotation and translation is dependent on the moment of inertia of the bath molecule. The simulations show that the low-frequency modes of the vibrationally excited pyrazine contribute most to the strong collisions. The majority of collisions lead to small DeltaE values and primarily involve single encounters between the energy donor and acceptor. The large DeltaE exchanges result from both single impulsive encounters and chattering collisions that involve multiple encounters.

  4. CO2LD: An innovation educational project for High Degree Professional Training in Refrigeration

    Directory of Open Access Journals (Sweden)

    Ramon Cabello Lopez

    2013-12-01

    Full Text Available Refrigeration is one of the technology sectors which has suffered most changes in the last twenty years, because of the negative impact of the fluids used in the refrigeration cycles, the refrigerants, due to their impact in the ozone layer and the promotion of the global warming. Due to the negative impacts of the fluids, the European Union has established several directives to restrict the use of refrigerant fluids, causing the need of adaptation of the sector to the new regulations. The adaptation of the refrigeration sector to the new regulations must be done by all agents involved, included the training and education of the future refrigeration technicians. To allow this, the project CO2LD has been developed to introduce the future technology in the High Degree Professional Training in Refrigeration. The objective of the project consisted on introducing more efficient and more sustainable refrigeration systems, R134a/CO2 cascade cycles, in the studies of High Degree Professional Training in Refrigeration, and create a collaborative framework among students, secondary-schools, refrigeration technicians, refrigeration companies and the University to facilitate the know-how transfer. This paper presents the objectives of the project, describes its development and analyses the main conclusions of it.

  5. Investigation of heat transfer and pressure drop of CO(2) two-phase flow in a horizontal minichannel

    CERN Document Server

    Wu, J; Haug, F; Franke, C; Bremer, J; Eisel, T; Koettig, T

    2011-01-01

    An innovative cooling system based on evaporative CO(2) two-phase flow is under investigation for the tracker detectors upgrade at CERN (European Organization for Nuclear Research). The radiation hardness and the excellent thermodynamic properties emphasize carbon dioxide as a cooling agent in the foreseen minichannels. A circular stainless steel tube in horizontal orientation with an inner diameter of 1.42 mm and a length of 0.3 m has been used as a test section to perform the step-wise scanning of the vapor quality in the entire two-phase region. To characterize the heat transfer and the pressure drop depending on the vapor quality in the tube, measurements have been performed by varying the mass flux from 300 to 600 kg/m(2) s, the heat flux from 7.5 to 29.8 kW/m(2) and the saturation temperature from -40 to 0 degrees C (reduced pressures from 0.136 to 0.472). Heat transfer coefficients between 4 kW/m(2) K and 28 kW/m(2) K and pressure gradients up to 75 kPa/m were registered. The measured data was analyzed...

  6. Tracing high-pressure metamorphism in marbles: Phase relations in high-grade aluminous calcite-dolomite marbles from the Greek Rhodope massif in the system CaO-MgO-Al 2O 3-SiO 2-CO 2 and indications of prior aragonite

    Science.gov (United States)

    Proyer, A.; Mposkos, E.; Baziotis, I.; Hoinkes, G.

    2008-08-01

    Four different types of parageneses of the minerals calcite, dolomite, diopside, forsterite, spinel, amphibole (pargasite), (Ti-)clinohumite and phlogopite were observed in calcite-dolomite marbles collected in the Kimi-Complex of the Rhodope Metamorphic Province (RMP). The presence of former aragonite can be inferred from carbonate inclusions, which, in combination with an analysis of phase relations in the simplified system CaO-MgO-Al 2O 3-SiO 2-CO 2 (CMAS-CO 2) show that the mineral assemblages preserved in these marbles most likely equilibrated at the aragonite-calcite transition, slightly below the coesite stability field, at ca. 720 °C, 25 kbar and aCO 2 ~ 0.01. The thermodynamic model predicts that no matter what activity of CO 2, garnet has to be present in aluminous calcite-dolomite-marble at UHP conditions.

  7. Modematic: a fast laser beam analyzing system for high power CO2-laser beams

    Science.gov (United States)

    Olsen, Flemming O.; Ulrich, Dan

    2003-03-01

    The performance of an industrial laser is very much depending upon the characteristics of the laser beam. The ISO standards 11146 and 11154 describing test methods for laser beam parameters have been approved. To implement these methods in industry is difficult and especially for the infrared laser sources, such as the CO2-laser, the availabl analyzing systems are slow, difficult to apply and having limited reliability due to the nature of the detection methods. In an EUREKA-project the goal was defined to develop a laser beam analyzing system dedicated to high power CO2-lasers, which could fulfill the demands for an entire analyzing system, automating the time consuming pre-alignment and beam conditioning work required before a beam mode analyses, automating the analyzing sequences and data analysis required to determine the laser beam caustics and last but not least to deliver reliable close to real time data to the operator. The results of this project work will be described in this paper. The research project has led to the development of the Modematic laser beam analyzer, which is ready for the market.

  8. Theoretical And Experimental Investigations On The Plasma Of A CO2 High Power Laser

    Science.gov (United States)

    Abel, W.; Wallter, B.

    1984-03-01

    The CO2 high power laser is increasingly used in material processing. This application of the laser has to meet some requirements: at one hand the laser is a tool free of wastage, but at the other hand is to guarantee that the properties of that tool are constant in time. Therefore power, geometry and mode of the beam have to be stable over long intervalls, even if the laser is used in rough industrial environment. Otherwise laser material processing would not be competitive. The beam quality is affected by all components of the laser - by the CO2 plasma and its IR - amplification, by the resonator which at last generates the beam by optical feedback, and also by the electric power supply whose effects on the plasma may be measured at the laser beam. A transversal flow laser has been developed at the Technical University of Vienna in cooperation with VOest-Alpine AG, Linz (Austria). This laser produces 1 kW of beam power with unfolded resonator. It was subject to investigations presented in this paper.

  9. Hierarchical CuCo2O4 nanobelts as a supercapacitor electrode with high areal and specific capacitance

    International Nuclear Information System (INIS)

    Vijayakumar, Subbukalai; Lee, Seong-Hun; Ryu, Kwang-Sun

    2015-01-01

    Highlights: • First time we report the synthesis of CuCo 2 O 4 nanobelts using hydrothermal method. • The spinel CuCo 2 O 4 nanobelts exhibit maximum areal capacitance of 2.42 F cm −2 . • After 1800 cycles, 127% of the initial specific capacitance was retained. - Abstract: One dimensional hierarchical CuCo 2 O 4 nanobelt like architecture was synthesized via hydrothermal method. The synthesized nanomaterial was characterized using X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The TEM image clearly shows the nanobelt like architecture of CuCo 2 O 4 . The supercapacitor properties of CuCo 2 O 4 nanobelts electrode were tested using cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy. The spinel CuCo 2 O 4 nanobelts exhibit maximum areal and specific capacitance of 2.42 F cm −2 (809 F g −1 ). After 1800 continuous charge-discharge cycles, 127% of the initial capacitance was retained. This superior electrochemical supercapacitor property is mainly due to increased surface area and ion transport of nanobelt like architecture. The charge transfer resistance (R ct ) value of CuCo 2 O 4 nanobelt electrode is 3.85 Ω. This high capacitance and cyclic stability demonstrate that the prepared CuCo 2 O 4 nanobelts are a promising candidate for supercapacitors.

  10. Natural high pCO2 increases autotrophy in Anemonia viridis (Anthozoa) as revealed from stable isotope (C, N) analysis.

    Science.gov (United States)

    Horwitz, Rael; Borell, Esther M; Yam, Ruth; Shemesh, Aldo; Fine, Maoz

    2015-03-05

    Contemporary cnidarian-algae symbioses are challenged by increasing CO2 concentrations (ocean warming and acidification) affecting organisms' biological performance. We examined the natural variability of carbon and nitrogen isotopes in the symbiotic sea anemone Anemonia viridis to investigate dietary shifts (autotrophy/heterotrophy) along a natural pCO2 gradient at the island of Vulcano, Italy. δ(13)C values for both algal symbionts (Symbiodinium) and host tissue of A. viridis became significantly lighter with increasing seawater pCO2. Together with a decrease in the difference between δ(13)C values of both fractions at the higher pCO2 sites, these results indicate there is a greater net autotrophic input to the A. viridis carbon budget under high pCO2 conditions. δ(15)N values and C/N ratios did not change in Symbiodinium and host tissue along the pCO2 gradient. Additional physiological parameters revealed anemone protein and Symbiodinium chlorophyll a remained unaltered among sites. Symbiodinium density was similar among sites yet their mitotic index increased in anemones under elevated pCO2. Overall, our findings show that A. viridis is characterized by a higher autotrophic/heterotrophic ratio as pCO2 increases. The unique trophic flexibility of this species may give it a competitive advantage and enable its potential acclimation and ecological success in the future under increased ocean acidification.

  11. High blood pressure - children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007696.htm High blood pressure - children To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  12. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  13. High blood pressure - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  14. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  15. High-pressure microbiology

    National Research Council Canada - National Science Library

    Michiels, Chris; Bartlett, Douglas Hoyt; Aertsen, Abram

    2008-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High Hydrostatic Pressure Effects in the Biosphere: from Molecules to Microbiology * Filip Meersman and Karel Heremans . . . . . . . . . . . . 2. Effects...

  16. Core/shell structure NiCo2O4@MnCo2O4 nanofibers fabricated by different temperatures for high-performance supercapacitors

    Science.gov (United States)

    Wang, Qing; Qin, Xuefeng; Jiang, Pengcheng; Dai, Jianfeng; Li, Weixue; Gao, Haoran

    2018-03-01

    Core/shell structure NiCo2O4@MnCo2O4 nanofibers (NiCo2O4@MnCo2O4 NFs) were prepared by a facile co-electrospinning method and heat treatment. The composites annealed at 500 °C have a complete, continuously obvious core/shell structure, and clear interface of composites with good morphology, while annealed at 600 °C were stacked on each other and were unable to sustain three-dimensional network structures and 700 °C calcination have completely lost one-dimensional structure. The core NiCo2O4 is about 70 nm in diameter and the MnCo2O4 shell behaves a thickness about 60 nm. When investigated as an electrode material for supercapacitors, the NiCo2O4@MnCo2O4 NFs annealed at 500 °C exihibited the specific capacitance of 463 F g-1 (0.926 F cm-2) at 1 A g-1, higher than that annealed at 600 °C 362 F g-1, 1 A g-1 (0.724 F cm-2, 1 A g-1) and 700 °C 283 F g-1, 1 A g-1 (0.566 F cm-2, 1 A g-1). These results suggest that core/shell NiCo2O4@MnCo2O4 NFs annealed at 500 °C have formed a good morphology with continuously complete core/shell structure which lead to good properties would be potential electrodes for supercapacitors.

  17. Dissociation of NH3 and NH2D by high power CO2 laser radiation

    International Nuclear Information System (INIS)

    Jacobs, R.R.

    1976-08-01

    Multiquantum dissociation of polyatomics using intense CO 2 lasers resulting in isotopic enrichment has been demonstrated for several molecules. In this presentation, the possibility of selective dissociation of NH 3 and NH 2 D by high power laser radiation at 10 μm will be considered. Relevant work performed at the Lawrence Livermore Laboratory and elsewhere will be summarized. In this review, attention will be given to four distinct mechanisms that can play varying degrees of importance in such investigations. Discussion will deal with the usefulness of two-resonant-frequency molecular excitation, the role of buffer gases, and the need to monitor the yields into the ground and excited electronic states of the dissociated fragments

  18. Calcifying invertebrates succeed in a naturally CO2-rich coastal habitat but are threatened by high levels of future acidification

    Directory of Open Access Journals (Sweden)

    M. Wahl

    2010-11-01

    Full Text Available CO2 emissions are leading to an acidification of the oceans. Predicting marine community vulnerability towards acidification is difficult, as adaptation processes cannot be accounted for in most experimental studies. Naturally CO2 enriched sites thus can serve as valuable proxies for future changes in community structure. Here we describe a natural analogue site in the Western Baltic Sea. Seawater pCO2 in Kiel Fjord is elevated for large parts of the year due to upwelling of CO2 rich waters. Peak pCO2 values of >230 Pa (>2300 μatm and pHNBS values of pCO2 values are ~70 Pa (~700 μatm. In contrast to previously described naturally CO2 enriched sites that have suggested a progressive displacement of calcifying auto- and heterotrophic species, the macrobenthic community in Kiel Fjord is dominated by calcifying invertebrates. We show that blue mussels from Kiel Fjord can maintain control rates of somatic and shell growth at a pCO2 of 142 Pa (1400 μatm, pHNBS = 7.7. Juvenile mussel recruitment peaks during the summer months, when high water pCO2 values of ~100 Pa (~1000 μatm prevail. Our findings indicate that calcifying keystone species may be able to cope with surface ocean pHNBS values projected for the end of this century when food supply is sufficient. However, owing to non-linear synergistic effects of future acidification and upwelling of corrosive water, peak seawater pCO2 in Kiel Fjord and many other productive estuarine habitats could increase to values >400 Pa (>4000 μatm. These changes will most likely affect calcification and recruitment, and increase external shell dissolution.

  19. A Micro CO2 Gas Sensor Based on Sensing of pH-Sensitive Hydrogel Swelling by Means of a Pressure Sensor

    NARCIS (Netherlands)

    Herber, S.; Bomer, Johan G.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2005-01-01

    In this paper a sensor is presented for the detection of carbon dioxide gas inside the stomach in order to diagnose gastrointestinal ischemia. The operational principle of the sensor is measuring the CO2 induced pressure generation of a confined pH-sensitive hydrogel by means of a micro pressure

  20. The future of the northeast Atlantic benthic flora in a high CO2 world.

    Science.gov (United States)

    Brodie, Juliet; Williamson, Christopher J; Smale, Dan A; Kamenos, Nicholas A; Mieszkowska, Nova; Santos, Rui; Cunliffe, Michael; Steinke, Michael; Yesson, Christopher; Anderson, Kathryn M; Asnaghi, Valentina; Brownlee, Colin; Burdett, Heidi L; Burrows, Michael T; Collins, Sinead; Donohue, Penelope J C; Harvey, Ben; Foggo, Andrew; Noisette, Fanny; Nunes, Joana; Ragazzola, Federica; Raven, John A; Schmidt, Daniela N; Suggett, David; Teichberg, Mirta; Hall-Spencer, Jason M

    2014-07-01

    Seaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north. Seagrasses will proliferate, and associated epiphytes switch from calcified algae to diatoms and filamentous species. Invasive species will thrive in niches liberated by loss of native species and spread via exponential development of artificial marine structures. Combined impacts of seawater warming, ocean acidification, and increased storminess may replace structurally diverse seaweed canopies, with associated calcified and noncalcified flora, with simple habitats dominated by noncalcified, turf-forming seaweeds.

  1. Hierarchical NiCo2 O4 nanosheets grown on Ni nanofoam as high-performance electrodes for supercapacitors.

    Science.gov (United States)

    Gao, Guoxin; Wu, Hao Bin; Ding, Shujiang; Liu, Li-Min; Lou, Xiong Wen David

    2015-02-18

    A high-performance electrode for supercapacitors is designed and synthesized by growing electroactive NiCo2 O4 nanosheets on conductive Ni nanofoam. Because of the structural advantages, the as-prepared Ni@NiCo2 O4 hybrid nanostructure exhibits significantly improved electrochemical performance with high capacitance, excellent rate capability, and good cycling stability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4 using the cavity ring-down spectroscopy (CRDS technique

    Directory of Open Access Journals (Sweden)

    V. Y. Chow

    2010-03-01

    Full Text Available High-accuracy continuous measurements of greenhouse gases (CO2 and CH4 during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

  3. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) using the cavity ring-down spectroscopy (CRDS) technique

    Science.gov (United States)

    Chen, H.; Winderlich, J.; Gerbig, C.; Hoefer, A.; Rella, C. W.; Crosson, E. R.; van Pelt, A. D.; Steinbach, J.; Kolle, O.; Beck, V.; Daube, B. C.; Gottlieb, E. W.; Chow, V. Y.; Santoni, G. W.; Wofsy, S. C.

    2010-03-01

    High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

  4. Pulse propagation properties in high-power CO2 laser system for laser fusion

    International Nuclear Information System (INIS)

    Daido, H.; Inoue, M.; Fujita, H.; Matoba, M.; Nakai, S.

    1981-01-01

    The simulation results of nonlinear propagation properties in the CO 2 laser system using a simulation model of the SF 6 saturable absorbers and the CO 2 laser amplifiers agree well with the experimental results. The technical problems of the simultaneous irradiation of the multi-beams to a target are also discussed. (author)

  5. Dependence of the absorption of pulsed CO2-laser radiation by silane on wavenumber, fluence, pulse duration, temperature, optical path length, and pressure of absorbing and nonabsorbing gases

    International Nuclear Information System (INIS)

    Blazejowski, J.; Gruzdiewa, L.; Rulewski, J.; Lampe, F.W.

    1995-01-01

    The absorption of three lines [P(20), 944.2 cm -1 ; P(14), 949.2 cm -1 ; and R(24), 978.5 cm -1 ] of the pulsed CO 2 laser (00 0 1--10 0 0 transition) by SiH 4 was measured at various pulse energy, pulse duration, temperature, optical path length, and pressure of the compound and nonabsorbing foreign gases. In addition, low intensity infrared absorption spectrum of silane was compared with high intensity absorption characteristics for all lines of the pulsed CO 2 laser. The experimental dependencies show deviations from the phenomenological Beer--Lambert law which can be considered as arising from the high intensity of an incident radiation and collisions of absorbing molecules with surroundings. These effects were included into the expression, being an extended form of the Beer--Lambert law, which reasonably approximates all experimental data. The results, except for extending knowledge on the interaction of a high power laser radiation with matter, can help understanding and planning processes leading to preparation of silicon-containing technologically important materials

  6. Qualidade de maçãs cv. gala armazenadas em diferentes pressões parciais de O2 e CO2 Quality of 'gala' apples stored at different partial pressures of O2 and CO2

    Directory of Open Access Journals (Sweden)

    Auri Brackmann

    2000-06-01

    Full Text Available Este trabalho teve como objetivo verificar os efeitos da temperatura e pressões parciais de O2 e CO2 sobre a qualidade da maçã cv. Gala armazenada em atmosfera controlada. O delineamento experimental foi o inteiramente casualizado com três repetições de 30 frutos. Os tratamentos foram: 1,0 kPa de O2 e 2,0 kPa de CO2; 1,0 kPa de O2 e 3,0 kPa de CO2; 1,0 kPa de O2 e 4,0 kPa de CO2; 0,75 kPa de O2 e 2,0 kPa de CO2; 0,75 kPa de O2 e 3,0 kPa de CO2 e, 21,0 kPa de O2 e 0,0 kPa de CO2 na temperatura de 0 e 1ºC. A UR permaneceu em torno de 97%. O período de armazenamento foi de oito meses, sendo que as análises foram realizadas no momento da retirada dos frutos das câmaras e após sete dias de exposição dos mesmos à temperatura ambiente (24ºC. Avaliou-se firmeza de polpa, acidez titulável, teor de sólidos solúveis totais, cor de fundo da epiderme, degenerescência senescente, rachaduras e podridões. Melhor conservação da firmeza de polpa, acidez titulável e teores de sólidos solúveis totais foram encontrados com 0,75 a 1 kPa de O2, combinado com 3,0 kPa de CO2 na temperatura de 1ºC. A maçã apresentou degenerescência senescente em 4,0 kPa de CO2 e também quando utilizou-se a temperatura de 0ºC. A temperatura de 1ºC, em relação a 0ºC, manteve melhor qualidade dos frutos após oito meses de armazenamento.To evaluate the effects of the temperature and partial pressures of O2 and CO2 on the quality of `Gala' apples stored under controlled atmosphere an experiment was carried out using a completely randomized design with three replicates, each of 30 fruits. The treatments were: 1.0 kPa of O2 and 2.0 kPa of CO2; 1.0 kPa of O2 and 3.0 kPa of CO2; 1.0 kPa of O2 and 4.0 kPa of CO2; 0.75 kPa of O2 and 2.0 kPa of CO2; 0.75 kPa of O2 and 3.0 kPa of CO2; 21.0 kPa of O2 and 0.0 kPa of CO2 at the temperatures of 0 and 1ºC. RH was mantained around 97%. After 8 months, fruit quality was assessed at the opening of the CA chambers, and

  7. High-frequency productivity estimates for a lake from free-water CO2 concentration measurements

    Science.gov (United States)

    Provenzale, Maria; Ojala, Anne; Heiskanen, Jouni; Erkkilä, Kukka-Maaria; Mammarella, Ivan; Hari, Pertti; Vesala, Timo

    2018-04-01

    Lakes are important actors in biogeochemical cycles and a powerful natural source of CO2. However, they are not yet fully integrated in carbon global budgets, and the carbon cycle in the water is still poorly understood. In freshwater ecosystems, productivity studies have usually been carried out with traditional methods (bottle incubations, 14C technique), which are imprecise and have a poor temporal resolution. Consequently, our ability to quantify and predict the net ecosystem productivity (NEP) is limited: the estimates are prone to errors and the NEP cannot be parameterised from environmental variables. Here we expand the testing of a free-water method based on the direct measurement of the CO2 concentration in the water. The approach was first proposed in 2008, but was tested on a very short data set (3 days) under specific conditions (autumn turnover); despite showing promising results, this method has been neglected by the scientific community. We tested the method under different conditions (summer stratification, typical summer conditions for boreal dark-water lakes) and on a much longer data set (40 days), and quantitatively validated it comparing our data and productivity models. We were able to evaluate the NEP with a high temporal resolution (minutes) and found a very good agreement (R2 ≥ 0.71) with the models. We also estimated the parameters of the productivity-irradiance (PI) curves that allow the calculation of the NEP from irradiance and water temperature. Overall, our work shows that the approach is suitable for productivity studies under a wider range of conditions, and is an important step towards developing this method so that it becomes more widely used.

  8. High-frequency productivity estimates for a lake from free-water CO2 concentration measurements

    Directory of Open Access Journals (Sweden)

    M. Provenzale

    2018-04-01

    Full Text Available Lakes are important actors in biogeochemical cycles and a powerful natural source of CO2. However, they are not yet fully integrated in carbon global budgets, and the carbon cycle in the water is still poorly understood. In freshwater ecosystems, productivity studies have usually been carried out with traditional methods (bottle incubations, 14C technique, which are imprecise and have a poor temporal resolution. Consequently, our ability to quantify and predict the net ecosystem productivity (NEP is limited: the estimates are prone to errors and the NEP cannot be parameterised from environmental variables. Here we expand the testing of a free-water method based on the direct measurement of the CO2 concentration in the water. The approach was first proposed in 2008, but was tested on a very short data set (3 days under specific conditions (autumn turnover; despite showing promising results, this method has been neglected by the scientific community. We tested the method under different conditions (summer stratification, typical summer conditions for boreal dark-water lakes and on a much longer data set (40 days, and quantitatively validated it comparing our data and productivity models. We were able to evaluate the NEP with a high temporal resolution (minutes and found a very good agreement (R2 ≥ 0.71 with the models. We also estimated the parameters of the productivity–irradiance (PI curves that allow the calculation of the NEP from irradiance and water temperature. Overall, our work shows that the approach is suitable for productivity studies under a wider range of conditions, and is an important step towards developing this method so that it becomes more widely used.

  9. High-pressure apparatus

    NARCIS (Netherlands)

    Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.

    1999-01-01

    The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

  10. Flexible and High Performance Supercapacitors Based on NiCo2O4for Wide Temperature Range Applications

    Science.gov (United States)

    Gupta, Ram K.; Candler, John; Palchoudhury, Soubantika; Ramasamy, Karthik; Gupta, Bipin Kumar

    2015-10-01

    Binder free nanostructured NiCo2O4 were grown using a facile hydrothermal technique. X-ray diffraction patterns confirmed the phase purity of NiCo2O4. The surface morphology and microstructure of the NiCo2O4 analyzed by scanning electron microscopy (SEM) showed flower-like morphology composed of needle-like structures. The potential application of binder free NiCo2O4 as an electrode for supercapacitor devices was investigated using electrochemical methods. The cyclic voltammograms of NiCo2O4 electrode using alkaline aqueous electrolytes showed the presence of redox peaks suggesting pseudocapacitance behavior. Quasi-solid state supercapacitor device fabricated by sandwiching two NiCo2O4 electrodes and separating them by ion transporting layer. The performance of the device was tested using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The device showed excellent flexibility and cyclic stability. The temperature dependent charge storage capacity was measured for their variable temperature applications. Specific capacitance of the device was enhanced by ~150% on raising the temperature from 20 to 60 °C. Hence, the results suggest that NiCo2O4 grown under these conditions could be a suitable material for high performance supercapacitor devices that can be operated at variable temperatures.

  11. Constructing robust and highly-selective hydrogel membranes by bioadhesion-inspired method for CO 2 separation

    KAUST Repository

    Wu, Yingzhen

    2018-06-01

    Water-swollen hydrogel membranes are good candidates for CO2 separations due to the favorable solubility of CO2 in water. However, the excessive amount of water often causes the poor mechanical property and low selectivity. Herein, we propose a bioadhesion-inspired method to construct robust and high-performance CO2 separation membranes via in situ generation of polydopamine (PDA) nanoaggregates within poly (vinyl alcohol) (PVA) matrix. PDA nanoaggregates entangled with PVA chains and formed hydrogen bonding with hydroxyl groups from PVA chains. Physical cross-linking occurred between PVA chains and PDA nanoaggregates. Compared with the PVA membrane, the PVA-PDA hybrid membrane with the dopamine content of 0.5mol% exhibited a 1.7-fold increase in tensile strength and a 2.2-fold increase in the tensile modulus. The membranes were used for CO2/CH4 separation. The physical cross-linking resulted in a PVA chain rigidification region around PDA nanoaggregates, which hindered the penetration of larger-size gas molecules and thus enhancing the CO2/CH4 selectivity. Moreover, the abundant amine groups from PDA nanoaggregates could facilitate CO2 transport. The optimized hybrid hydrogel membrane exhibited CO2/CH4 selectivity of 43.2, which was 43.85% higher than that of the PVA membrane. The bioadhesion-inspired method opens up new opportunities to exploit the potential application of hydrogel membranes.

  12. High blood pressure - adults

    Science.gov (United States)

    ... pressure is found. This is called essential hypertension. High blood pressure that is caused by another medical condition or medicine you are taking is called secondary hypertension. Secondary hypertension may be due to: Chronic ...

  13. Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO2 emissions

    Directory of Open Access Journals (Sweden)

    S. Feng

    2016-07-01

    Full Text Available Megacities are major sources of anthropogenic fossil fuel CO2 (FFCO2 emissions. The spatial extents of these large urban systems cover areas of 10 000 km2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO2 emissions over the Los Angeles (LA megacity area. The Weather Research and Forecasting (WRF-Chem model was coupled to a very high-resolution FFCO2 emission product, Hestia-LA, to simulate atmospheric CO2 concentrations across the LA megacity at spatial resolutions as fine as  ∼  1 km. We evaluated multiple WRF configurations, selecting one that minimized errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010. Our results show no significant difference between moderate-resolution (4 km and high-resolution (1.3 km simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution and Hestia-LA (1.3 km resolution fossil fuel CO2 emission products to evaluate the impact of the spatial resolution of the CO2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO2 concentrations. We find that high spatial resolution in the fossil fuel CO2 emissions is more important than in the atmospheric model to capture CO2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO2 fields reflect the coverage of

  14. Calculation of mass transfer in the remote cutting of metals by radiation of a high-power repetitively pulsed CO2 laser

    International Nuclear Information System (INIS)

    Gladush, G G; Rodionov, N B

    2002-01-01

    The mechanism of remote cutting of steel plates by radiation of a high-power repetitively pulsed CO 2 laser is theoretically studied. The models of melt removal by the gravity force and the recoil pressure of material vapour are proposed and the sufficient conditions for the initiation of cutting are determined. A numerical model of a thermally thin plate was employed to describe the cutting for large focal spots. (interaction of laser radiation with matter. laser plasma)

  15. Multi-shelled ZnCo2O4 yolk-shell spheres for high-performance acetone gas sensor

    Science.gov (United States)

    Xiong, Ya; Zhu, Zongye; Ding, Degong; Lu, Wenbo; Xue, Qingzhong

    2018-06-01

    In the present study, multi-shelled ZnCo2O4 yolk-shell spheres have been successfully prepared by using carbonaceous microspheres as templates. It is found that the multi-shelled ZnCo2O4 yolk-shell spheres based sensor shows optimal sensing performances (response value of 38.2, response/recovery time of 19 s/71 s) toward 500 ppm acetone at 200 °C. In addition, this sensor exhibits a low detection limit of 0.5 ppm acetone (response value of 1.36) and a good selectivity toward hydrogen, methane, ethanol, ammonia and carbon dioxide. Furthermore, it is demonstrated that acetone gas response of multi-shelled ZnCo2O4 yolk-shell spheres is significantly better than that of ZnCo2O4 nanotubes and ZnCo2O4 nanosheets. High acetone response of the multi-shelled ZnCo2O4 yolk-shell spheres is attributed to the enhanced gas accessibility of the multi-shell morphology caused by the small crystalline size and high specific surface area while the short response/recovery time is mainly related to the rapid gas diffusion determined by the highly porous structure. Our work puts forward an exciting opportunity in designing various yolk-shelled structures for multipurpose applications.

  16. The High Accuracy Measurement of CO2 Mixing Ratio Profiles Using Ground Based 1.6 μm CO2-DIAL with Temperature Measurement Techniques in the Lower-Atmosphere

    Science.gov (United States)

    Abo, M.; Shibata, Y.; Nagasawa, C.

    2017-12-01

    We have developed a ground based direct detection three-wavelength 1.6 μm differential absorption lidar (DIAL) to achieve measurements of vertical CO2 concentration and temperature profiles in the atmosphere. As the spectra of absorption lines of any molecules are influenced basically by the temperature and pressure in the atmosphere, it is important to measure them simultaneously so that the better accuracy of the DIAL measurement is realized. Conventionally, we have obtained the vertical profile of absorption cross sections using the atmospheric temperature profile by the objective analysis and the atmospheric pressure profile calculated by the pressure height equation. Comparison of atmospheric pressure profiles calculated from this equation and those obtained from radiosonde observations at Tateno, Japan is consistent within 0.2 % below 3 km altitude. But the temperature dependency of the CO2 density is 0.25 %/°C near the surface. Moreover, the CO2 concentration is often evaluated by the mixing ratio. Because the air density is related by the ideal gas law, the mixing ratio is also related by the atmospheric temperature. Therefore, the temperature affects not only accuracy of CO2 concentration but the CO2 mixing ratio. In this paper, some experimental results of the simultaneous measurement of atmospheric temperature profiles and CO2 mixing ratio profiles are reported from 0.4 to 2.5 km altitude using the three-wavelength 1.6 μm DIAL system. Temperature profiles of CO2 DIAL measurement were sometimes different from those of objective analysis below 1.5 km altitude. These differences are considered to be due to regionality at the lidar site. The temperature difference of 5.0 °C corresponds to a CO2 mixing ratio difference of 8.0 ppm at 500 m altitude. This cannot be ignored in estimates of regional sources and sinks of CO2. This three-wavelength CO2 DIAL technique can estimate accurately temporal behavior of CO2 mixing ratio profiles in the lower atmosphere

  17. Long-term changes in CO(2) emissions in Austria and Czechoslovakia-Identifying the drivers of environmental pressures.

    Science.gov (United States)

    Gingrich, Simone; Kušková, Petra; Steinberger, Julia K

    2011-02-01

    This study presents fossil-fuel related CO(2) emissions in Austria and Czechoslovakia (current Czech Republic and Slovakia) for 1830-2000. The drivers of CO(2) emissions are discussed by investigating the variables of the standard Kaya identity for 1920-2000 and conducting a comparative Index Decomposition Analysis. Proxy data on industrial production and household consumption are analysed to understand the role of the economic structure. CO(2) emissions increased in both countries in the long run. Czechoslovakia was a stronger emitter of CO(2) throughout the time period, but per-capita emissions significantly differed only after World War I, when Czechoslovakia and Austria became independent. The difference in CO(2) emissions increased until the mid-1980s (the period of communism in Czechoslovakia), explained by the energy intensity and the composition effects, and higher industrial production in Czechoslovakia. Counterbalancing factors were the income effect and household consumption. After the Velvet revolution in 1990, Czechoslovak CO(2) emissions decreased, and the energy composition effect (and industrial production) lost importance. Despite their different political and economic development, Austria and Czechoslovakia reached similar levels of per-capita CO(2) emissions in the late 20th century. Neither Austrian "eco-efficiency" nor Czechoslovak restructuring have been effective in reducing CO(2) emissions to a sustainable level.

  18. Long-term changes in CO2 emissions in Austria and Czechoslovakia—Identifying the drivers of environmental pressures

    Science.gov (United States)

    Gingrich, Simone; Kušková, Petra; Steinberger, Julia K.

    2011-01-01

    This study presents fossil-fuel related CO2 emissions in Austria and Czechoslovakia (current Czech Republic and Slovakia) for 1830–2000. The drivers of CO2 emissions are discussed by investigating the variables of the standard Kaya identity for 1920–2000 and conducting a comparative Index Decomposition Analysis. Proxy data on industrial production and household consumption are analysed to understand the role of the economic structure. CO2 emissions increased in both countries in the long run. Czechoslovakia was a stronger emitter of CO2 throughout the time period, but per-capita emissions significantly differed only after World War I, when Czechoslovakia and Austria became independent. The difference in CO2 emissions increased until the mid-1980s (the period of communism in Czechoslovakia), explained by the energy intensity and the composition effects, and higher industrial production in Czechoslovakia. Counterbalancing factors were the income effect and household consumption. After the Velvet revolution in 1990, Czechoslovak CO2 emissions decreased, and the energy composition effect (and industrial production) lost importance. Despite their different political and economic development, Austria and Czechoslovakia reached similar levels of per-capita CO2 emissions in the late 20th century. Neither Austrian “eco-efficiency” nor Czechoslovak restructuring have been effective in reducing CO2 emissions to a sustainable level. PMID:21461052

  19. High CO2 emissions from the tropical Godavari estuary (India) associated with monsoon river discharges

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Kumar, N.A.; Prasad, V.R.; Venkataramana, V.; Appalanaidu, S.; Sridevi, B.; Kumar, B.S.K.; Bharati, M.D.; Subbaiah, C.V.; Acharyya, T.; Rao, G.D.; Viswanadham, R.; Gawade, L.; Manjary, D.T.; Kumar, P.P.; Rajeev, K.; Reddy, N.P.C.; Sarma, V.V.; Kumar, M.D.; Sadhuram, Y.; Murty, T.V.R.

    ). Air-water flux of CO 2 was estimated following Wanninkhof (1992) using measured wind speed. 3. Results and discussion The dam controlled freshwater discharge into the Godavari estuary was maximal in August (Fig. 2a). There was virtually... bacterioplankton. Appl. Environ. Microbiol.52,1298-1303. Lewis, E., and D.W.R. Wallace (1998). Program developed for CO2 system calculations. ORNL/CDIAC-105. Carbon dioxide information analysis center, Oak Ridge National Laboratory, U.S. Department of Energy...

  20. Lessons from two high CO2 worlds - future oceans and intensive aquaculture.

    Science.gov (United States)

    Ellis, Robert P; Urbina, Mauricio A; Wilson, Rod W

    2017-06-01

    Exponentially rising CO 2 (currently ~400 μatm) is driving climate change and causing acidification of both marine and freshwater environments. Physiologists have long known that CO 2 directly affects acid-base and ion regulation, respiratory function and aerobic performance in aquatic animals. More recently, many studies have demonstrated that elevated CO 2 projected for end of this century (e.g. 800-1000 μatm) can also impact physiology, and have substantial effects on behaviours linked to sensory stimuli (smell, hearing and vision) both having negative implications for fitness and survival. In contrast, the aquaculture industry was farming aquatic animals at CO 2 levels that far exceed end-of-century climate change projections (sometimes >10 000 μatm) long before the term 'ocean acidification' was coined, with limited detrimental effects reported. It is therefore vital to understand the reasons behind this apparent discrepancy. Potential explanations include 1) the use of 'control' CO 2 levels in aquaculture studies that go beyond 2100 projections in an ocean acidification context; 2) the relatively benign environment in aquaculture (abundant food, disease protection, absence of predators) compared to the wild; 3) aquaculture species having been chosen due to their natural tolerance to the intensive conditions, including CO 2 levels; or 4) the breeding of species within intensive aquaculture having further selected traits that confer tolerance to elevated CO 2 . We highlight this issue and outline the insights that climate change and aquaculture science can offer for both marine and freshwater settings. Integrating these two fields will stimulate discussion on the direction of future cross-disciplinary research. In doing so, this article aimed to optimize future research efforts and elucidate effective mitigation strategies for managing the negative impacts of elevated CO 2 on future aquatic ecosystems and the sustainability of fish and shellfish

  1. Saturated phase densities of (CO_2 + H_2O) at temperatures from (293 to 450) K and pressures up to 64 MPa

    International Nuclear Information System (INIS)

    Efika, Emmanuel C.; Hoballah, Rayane; Li, Xuesong; May, Eric F.; Nania, Manuela; Sanchez-Vicente, Yolanda; Martin Trusler, J.P.

    2016-01-01

    Highlights: • Saturated phase densities of CO_2 + H_2O were measured with a 1.5 kg · m"−"3 uncertainty. • Aqueous phase densities can be predicted within 3 kg · m"−"3 using empirical models. • The CO_2-rich phase density was within 8 kg · m"−"3 of pure CO_2 at the same (p, T). • The cubic EOS of Spycher and Pruess deviates from the data by up to about 8 kg · m"−"3. - Abstract: An apparatus consisting of an equilibrium cell connected to two vibrating tube densimeters and two syringe pumps was used to measure the saturated phase densities of (CO_2 + H_2O) at temperatures from (293 to 450) K and pressures up to 64 MPa, with estimated average standard uncertainties of 1.5 kg · m"−"3 for the CO_2-rich phase and 1.0 kg · m"−"3 for the aqueous phase. The densimeters were housed in the same thermostat as the equilibrium cell and were calibrated in situ using pure water, CO_2 and helium. Following mixing, samples of each saturated phase were displaced sequentially at constant pressure from the equilibrium cell into the vibrating tube densimeters connected to the top (CO_2-rich phase) and bottom (aqueous phase) of the cell. The aqueous phase densities are predicted to within 3 kg · m"−"3 using empirical models for the phase compositions and partial molar volumes of each component. However, a recently developed multi-parameter equation of state (EOS) for this binary mixture, Gernert and Span [32], was found to under predict the measured aqueous phase density by up to 13 kg · m"−"3. The density of the CO_2-rich phase was always within about 8 kg · m"−"3 of the density for pure CO_2 at the same pressure and temperature; the differences were most positive near the critical density, and became negative at temperatures above about 373 K and pressures below about 10 MPa. For this phase, the multi-parameter EOS of Gernert and Span describes the measured densities to within 5 kg · m"−"3, whereas the computationally-efficient cubic EOS model of

  2. Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

    KAUST Repository

    Babarao, Ravichandar

    2010-07-06

    The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.

  3. Thermoeconomic analysis of a novel zero-CO2-emission high-efficiency power cycle using LNG coldness

    International Nuclear Information System (INIS)

    Liu, Meng; Lior, Noam; Zhang, Na; Han, Wei

    2009-01-01

    This paper presents a thermoeconomic analysis aimed at the optimization of a novel zero-CO 2 and other emissions and high-efficiency power and refrigeration cogeneration system, COOLCEP-S (Patent pending), which uses the liquefied natural gas (LNG) coldness during its revaporization. It was predicted that at the turbine inlet temperature (TIT) of 900 C, the energy efficiency of the COOLCEP-S system reaches 59%. The thermoeconomic analysis determines the specific cost, the cost of electricity, the system payback period and the total net revenue. The optimization started by performing a thermodynamic sensitivity analysis, which has shown that for a fixed TIT and pressure ratio, the pinch point temperature difference in the recuperator, (delta)T p1 , and that in the condenser, (delta)T p2 are the most significant unconstrained variables to have a significant effect on the thermal performance of novel cycle. The payback period of this novel cycle (with fixed net power output of 20 MW and plant life of 40 years) was ∝5.9 years at most, and would be reduced to ∝3.1 years at most when there is a market for the refrigeration byproduct. The capital investment cost of the economically optimized plant is estimated to be about 1000 /kWe, and the cost of electricity is estimated to be 0.34-0.37 CNY/kWh (∝0.04 USD/kWh). These values are much lower than those of conventional coal power plants being installed at this time in China, which, in contrast to COOLCEP-S, do produce CO 2 emissions at that. (author)

  4. Equilibrium Total Pressure and CO2 Solubility in Binary and Ternary Aqueous Solutions of 2-(Diethylamino)ethanol (DEEA) and 3-(Methylamino)propylamine (MAPA)

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; Svendsen, Hallvard Fjøsne; Fosbøl, Philip Loldrup

    2014-01-01

    Equilibrium total pressures were measured and equilibrium CO2 partial pressures were calculated from the measured total pressure data in binary and ternary aqueous solutions of 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA). The measurements were carried out in a commercially...... available calorimeter used as an equilibrium cell. The examined systems were the binary aqueous solutions of 5 M DEEA, 2 M MAPA, and 1 M MAPA and the ternary aqueous mixtures of 5 M DEEA + 2 M MAPA (5D2M) and 5 M DEEA + 1 M MAPA (5D1M), which gave liquid–liquid phase split upon CO2 absorption. The total...... pressures were measured and the CO2 partial pressures were calculated as a function of CO2 loading at three different temperatures 40 °C, 80 °C, and 120 °C. All experiments were reproduced with good repeatability. The measurements were carried out for 30 mass % MEA solutions to validate the experimental...

  5. High temperature reactor: Driving force to convert CO2 to fuel - HTR2008-58132

    International Nuclear Information System (INIS)

    McCormick, J. L.

    2008-01-01

    The rapidly increasing cost of petroleum products and uncertainty of long-term supply have prompted the U.S. military to aggressively pursue production of alternative fuels (synfuels) such as coal-to-liquids (CTL). U.S. Air Force is particularly active in this effort while the entire military is involved in simultaneously developing fuel specifications for alternative fuels that enable a single fuel for the entire battle space; all ground vehicles, aircraft and fuel cells. By limiting its focus on coal, tar sands and oil shale resources, the military risks violating federal law which requires the use of synfuels that have life cycle greenhouse gas emissions less than or equal to emissions from conventional petroleum fuels. A climate-friendly option would use a high temperature nuclear reactor to split water. The hydrogen (H 2 ) would be used in the reverse water gas shift (RWGS) to react with carbon dioxide (CO 2 ) to produce carbon monoxide (CO) and water. The oxygen (O 2 ) would be fed into a supercritical (SC) coal furnace. The flue gas CO 2 emissions would be stripped of impurities before reacting with H 2 in a RWGS process. Resultant carbon monoxide (CO) is fed, with additional H2, (extra H 2 needed to adjust the stoichiometry: 2 moles H 2 to one mole CO) into a conventional Fischer-Tropsch synthesis (FTS) to produce a heavy wax which is cracked and isomerized and refined to Jet Propulsion 8 (JP-8) and Jet Propulsion 5 (JP-5) fuels. The entire process offers valuable carbon-offsets and multiple products that contribute to lower syn-fuel costs and to comply with the federal limitation imposed on syn-fuel purchases. While the entire process is not commercially available, component parts are being researched; their physical and chemical properties understood and some are state-of-the-art technologies. An international consortium should complete physical, chemical and economic flow sheets to determine the feasibility of this concept that, if pursued, has broad

  6. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 – O2 environment

    International Nuclear Information System (INIS)

    Farrokhzad, M A; Khan, T I

    2014-01-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al 2 O3 and TiO 2 ) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO 2 , 10% O 2 and 75% N 2 . This research investigates the effects of CO 2 and O 2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO 2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO 2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO 2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings

  7. Characterization of gypsum crystals exposed to a high CO2 concentration fog using x-ray

    International Nuclear Information System (INIS)

    Carreño-Márquez, I. J. A.; Castillo-Sandoval, I.; Esparza-Ponce, H. E.; Fuentes-Cobas, L.; Montero-Cabrera, M. E.

    2015-01-01

    In Chihuahua State, a little town called Naica has the largest gypsum single crystals in the world. The growth of these structures has been described as a long and stable process developed over thousands of years. Due to the change in the environmental conditions, these crystals could suffer alterations on their surface. In this project we study the cause of possible deterioration of the giant crystals and intend to suggest measures for their preservation. For this sake, our first experiment consists on several gypsum crystals that have been subjected in a climate chamber to a fog at high CO 2 concentration and 51 °C for a period of time of six months, extracting two crystals every 15 days. Then the crystals have been characterized through Grazing Incidence X-Ray Diffraction using a diffractometer PanAlytical X’PertPro with two different detectors; Xe-filled proportional detector and a Pixel 3D detector. The results were compared to determine which technique is the most suitable to study the degradation of gypsum single crystals. In the two cases, we have identified only the gypsum phase, but with different crystal plane orientations

  8. Cold cathode electron guns in the LASL high power short-pulse CO2 laser program

    International Nuclear Information System (INIS)

    Singer, S.; Ladish, J.S.; Nutter, M.J.

    1975-01-01

    The Electron Beam Controlled Discharge CO 2 Laser is now firmly established as the only high power short pulse laser amplifier that has been demonstrated to have scaling capabilities to large apertures and energies much greater than 100 J. These devices require a beam of energetic electrons to control the gas discharge that produces the required population inversion. Until recently, the electron source was usually a thermionic emitter, even for rather large lasers, whose heater requirements dwarfed the pulsed energies associated with the transient operation of the laser. With the advent of reliable cold-cathode electron guns, the operation of these lasers has been greatly simplified. At LASL, there are four electron beam controlled laser systems which are in operation, under construction, or in design: the 1 kJ system, now operational; the 2.5 kJ system; the 10 kJ system; and the 100 kJ system. Only the first uses thermionic-emitter electron guns; the remainder use or will use cold cathode sources. The operation of the 200 x 35 cm 2 two sided cold cathode electron gun used in the 2.5 kJ laser system and to be used in the 10 kJ laser is described

  9. Long-term changes in CO2 emissions in Austria and Czechoslovakia-Identifying the drivers of environmental pressures

    International Nuclear Information System (INIS)

    Gingrich, Simone; Kuskova, Petra; Steinberger, Julia K.

    2011-01-01

    This study presents fossil-fuel related CO 2 emissions in Austria and Czechoslovakia (current Czech Republic and Slovakia) for 1830-2000. The drivers of CO 2 emissions are discussed by investigating the variables of the standard Kaya identity for 1920-2000 and conducting a comparative Index Decomposition Analysis. Proxy data on industrial production and household consumption are analysed to understand the role of the economic structure. CO 2 emissions increased in both countries in the long run. Czechoslovakia was a stronger emitter of CO 2 throughout the time period, but per-capita emissions significantly differed only after World War I, when Czechoslovakia and Austria became independent. The difference in CO 2 emissions increased until the mid-1980s (the period of communism in Czechoslovakia), explained by the energy intensity and the composition effects, and higher industrial production in Czechoslovakia. Counterbalancing factors were the income effect and household consumption. After the Velvet revolution in 1990, Czechoslovak CO 2 emissions decreased, and the energy composition effect (and industrial production) lost importance. Despite their different political and economic development, Austria and Czechoslovakia reached similar levels of per-capita CO 2 emissions in the late 20th century. Neither Austrian 'eco-efficiency' nor Czechoslovak restructuring have been effective in reducing CO 2 emissions to a sustainable level. - Research Highlights: →CO 2 emissions in Austria and Czechoslovakia increased during industrialisation. →The differences were strongest during periods of different political regimes. →The main drivers for differences were energy composition and energy intensity.

  10. High plant species diversity indirectly mitigates CO 2- and N-induced effects on grasshopper growth

    Science.gov (United States)

    Strengbom, Joachim; Reich, Peter B.; Ritchie, Mark E.

    2008-09-01

    We examined how elevated atmospheric [CO 2] and higher rate of nitrogen (N) input may influence grasshopper growth by changing food plant quality and how such effects may be modified by species diversity of the plant community. We reared grasshopper nymphs ( Melanoplus femurrubrum) on Poa pratensis from field-grown monocultures or polycultures (16 species) that were subjected to either ambient or elevated levels of CO 2 and N. Grasshopper growth rate was higher on P. pratensis leaves grown in monocultures than in polycultures, higher on P. pratensis grown under elevated than under ambient [CO 2], and higher on P. pratensis grown under elevated than under ambient [N]. The higher growth rate observed on P. pratensis exposed to elevated [CO 2] was, however, less pronounced for polyculture- than monoculture-grown P. pratensis. Growth rate of the grasshoppers was positively correlated with leaf [N], [C], and concentration of soluble carbohydrates + lipids. Concentration of non-structural carbohydrates + lipids was higher in leaves grown under elevated than under ambient [CO 2], and the difference between P. pratensis grown under ambient and elevated [CO 2] was greater for monoculture- than polyculture-grown P. pratensis. In addition, leaf N concentration was higher in P. pratensis grown in monocultures than in polycultures, suggesting that plant species richness, indirectly, may influence insect performance by changed nutritional value of the plants. Because we found interactive effects between all factors included ([CO 2], [N], and plant species diversity), our results suggest that these parameters may influence plant-insect interactions in a complex way that is not predictable from the sum of single factor manipulations.

  11. [Research on soil bacteria under the impact of sealed CO2 leakage by high-throughput sequencing technology].

    Science.gov (United States)

    Tian, Di; Ma, Xin; Li, Yu-E; Zha, Liang-Song; Wu, Yang; Zou, Xiao-Xia; Liu, Shuang

    2013-10-01

    Carbon dioxide Capture and Storage has provided a new option for mitigating global anthropogenic CO2 emission with its unique advantages. However, there is a risk of the sealed CO2 leakage, bringing a serious threat to the ecology system. It is widely known that soil microorganisms are closely related to soil health, while the study on the impact of sequestered CO2 leakage on soil microorganisms is quite deficient. In this study, the leakage scenarios of sealed CO2 were constructed and the 16S rRNA genes of soil bacteria were sequenced by Illumina high-throughput sequencing technology on Miseq platform, and related biological analysis was conducted to explore the changes of soil bacterial abundance, diversity and structure. There were 486,645 reads for 43,017 OTUs of 15 soil samples and the results of biological analysis showed that there were differences in the abundance, diversity and community structure of soil bacterial community under different CO, leakage scenarios while the abundance and diversity of the bacterial community declined with the amplification of CO2 leakage quantity and leakage time, and some bacteria species became the dominant bacteria species in the bacteria community, therefore the increase of Acidobacteria species would be a biological indicator for the impact of sealed CO2 leakage on soil ecology system.

  12. Full synergistic effect of hydrothermal NiCo2O4 nanosheets/CuCo2O4 nanocones supported on Ni foam for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Wen, Shiyang; Liu, Yu; Bai, Hongye; Shao, Rong; Xu, Wei; Shi, Weidong

    2018-06-01

    In this work, a series of NiCo2O4/CuCo2O4 composites were prepared by a two-step hydrothermal method. The optimized NiCo2O4/CuCo2O4 electrode shows more than 5 times area capacitance (4.97 F cm-2) than pure NiCo2O4 at the current density of 1 mA cm-2. The best performance of sample assembled an asymmetric supercapacitor could reach up to 42 F g-1 at the current density of 1 A g-1. In addition, the maximum energy density of 15 W h kg-1 was achieved with the power density of 814 W kg-1. The as-prepared active electrode material also reveals excellent cycling stability with 90.6% capacitance retention after 5000 cycles. These results indicate potential application in developing energy storage devices with high energy density power density.

  13. Physiological advantages of dwarfing in surviving extinctions in high-CO2 oceans

    Science.gov (United States)

    Garilli, Vittorio; Rodolfo-Metalpa, Riccardo; Scuderi, Danilo; Brusca, Lorenzo; Parrinello, Daniela; Rastrick, Samuel P. S.; Foggo, Andy; Twitchett, Richard J.; Hall-Spencer, Jason M.; Milazzo, Marco

    2015-07-01

    Excessive CO2 in the present-day ocean-atmosphere system is causing ocean acidification, and is likely to cause a severe biodiversity decline in the future, mirroring effects in many past mass extinctions. Fossil records demonstrate that organisms surviving such events were often smaller than those before, a phenomenon called the Lilliput effect. Here, we show that two gastropod species adapted to acidified seawater at shallow-water CO2 seeps were smaller than those found in normal pH conditions and had higher mass-specific energy consumption but significantly lower whole-animal metabolic energy demand. These physiological changes allowed the animals to maintain calcification and to partially repair shell dissolution. These observations of the long-term chronic effects of increased CO2 levels forewarn of changes we can expect in marine ecosystems as CO2 emissions continue to rise unchecked, and support the hypothesis that ocean acidification contributed to past extinction events. The ability to adapt through dwarfing can confer physiological advantages as the rate of CO2 emissions continues to increase.

  14. High CO2 and silicate limitation synergistically increase the toxicity of Pseudo-nitzschia fraudulenta.

    Directory of Open Access Journals (Sweden)

    Avery O Tatters

    Full Text Available Anthropogenic CO(2 is progressively acidifying the ocean, but the responses of harmful algal bloom species that produce toxins that can bioaccumulate remain virtually unknown. The neurotoxin domoic acid is produced by the globally-distributed diatom genus Pseudo-nitzschia. This toxin is responsible for amnesic shellfish poisoning, which can result in illness or death in humans and regularly causes mass mortalities of marine mammals and birds. Domoic acid production by Pseudo-nitzschia cells is known to be regulated by nutrient availability, but potential interactions with increasing seawater CO(2 concentrations are poorly understood. Here we present experiments measuring domoic acid production by acclimatized cultures of Pseudo-nitzschia fraudulenta that demonstrate a strong synergism between projected future CO(2 levels (765 ppm and silicate-limited growth, which greatly increases cellular toxicity relative to growth under modern atmospheric (360 ppm or pre-industrial (200 ppm CO(2 conditions. Cellular Si:C ratios decrease with increasing CO(2, in a trend opposite to that seen for domoic acid production. The coastal California upwelling system where this species was isolated currently exhibits rapidly increasing levels of anthropogenic acidification, as well as widespread episodic silicate limitation of diatom growth. Our results suggest that the current ecosystem and human health impacts of toxic Pseudo-nitzschia blooms could be greatly exacerbated by future ocean acidification and 'carbon fertilization' of the coastal ocean.

  15. Day and Night Variability of CO2 Fluxes and Priming Effects under zea Mays Measured in High Resolution

    Science.gov (United States)

    Splettstoesser, Thomas; Pausch, Johanna

    2017-04-01

    Plant induced increase of soil organic matter turnover rates contribute to carbon emissions in agricultural land use systems. In order to better understand these rhizosphere priming effects, we conducted an experiment which enabled us to monitor CO2 fluxes under Zea mays plants in high resolution. The experiment was conducted in a climate chamber where the plants were grown in tightly sealed boxes for 40 days and CO2 efflux from soil was measured twice a day. Continuous 13C-CO2 label was used to allow differentiation between plant- and soil-derived CO2.This enabled us to monitor root respiration and soil organic matter turnover in the early stages of plant growth and to highlight changes in soil CO2 emissions and priming effects between day and night. The measurements were conducted with a PICARRO G2131-I C high-precision isotopic CO2 Analyzer (PICARRO INC.) utilizing an automated valve system governed by a CR1000 data logger (Campbell Scientific). After harvest roots and shoots were analyzed for 13C content. Microbial biomass, root length density and enzymatic activities in soil were measured and linked to soil organic matter turnover rates. Results show an increased soil CO2 efflux at day time periods and an overall increase with increasing plant biomass. No difference in chloroform fumigation extractable microbial biomass has been found but a strong negative priming effect was measured in the short experimental period, suggesting that the microbes shifted to the utilization of plant exudates without actual microbial growth triggered by the new labile C input. This is coherent with the observed shift in enzyme kinetics. With this experimental setup we show that measurement of priming effects in high resolution can be achieved.

  16. High Power OPO Laser and wavelength-controlled system for 1.6μm CO2-DIAL

    Science.gov (United States)

    Abo, M.; Nagasawa, C.; Shibata, Y.

    2009-12-01

    Unlike the existing 2.0μm CO2-DIAL, a high-energy pulse laser operating in the 1.6μm absorption band of CO2 has not been realized. Quasi phase matching (QPM) devices have high conversion efficiency and high beam quality due to their higher nonlinear optical coefficient. We adapt the PPMgLT crystal as the QPM device. The PPMgLT crystal had 3mm × 3mm apertures, and the periodically poled period was 30.9 μm, with the duty ratio close to the ideal value of 0.5. The beam quality of the pumping laser was exceed M2 ≥1.2. The repetition rate was 400 Hz and the energy was 35 mJ. The pumping laser pulse was injection-seeded by the continuous-wave (CW) fiber laser, which had a narrow spectrum. The pulse pumped the PPMgLT crystal in the ring cavity with a single pass through the dielectric mirror. The PPMgLT crystal was mounted on a copper holder, and the temperature was maintained at 40 °C using a Peltier module. The holder’s temperature was stabilized to within 0.01 °C when the copper holder was covered with a plastic case. The OPO ring cavity was a singly resonant oscillator optimized for the signal wave. Single-frequency oscillation of the PPMgLT OPO was achieved by injection seeding, as described in the following. The injection seeder was a DFB laser having a power of 30mW with a 1MHz oscillation spectrum. Their oscillation wavelength was coarse tuned by temperature and fine tuned by adjusting injection currents. The partial power of the online wavelength was split in the wavelength control unit. We locked the DFB laser as an injection seeder of the online wavelength onto the line center by referencing the fiber coupled multipath gas cell (path length 800mm) containing pure CO2 at a pressure of 700 Torr. Stabilization was estimated to within 1.8MHz rms of the line center of the CO2 absorption line by monitoring the feedback signal of a wavelength-controlled unit. Injection seeding of the PPMgLT OPO was performed by matching the cavity length to the seeder

  17. Dissemination of bacteria labeled with technetium-99m after laparotomy and abdominal insufflation with different CO2 pressures on rats; Disseminacao de bacterias marcadas com tecnecio-99m apos laparotomia e insuflacao com diferentes pressoes de CO2 em ratos

    Energy Technology Data Exchange (ETDEWEB)

    Pitombo, Marcos Bettini; Faria, Clarice Abreu dos Santos Albuquerque de; Steinbruck, Klaus [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Escola de Medicina]. E-mail: mpitombo@urbi.com.br; Bernardo, Luciana Camargo; Bernardo Filho, Mario[Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes (IBRAG). Lab. de Radiofarmacia Experimental

    2008-01-15

    Purpose: To asses the dissemination of bacteria labeled with technetium-99m (99mTc) from peritoneal cavity after different surgical procedures. Methods: Bacteria of the Escherichia coli species labeled with 99mTc were used in a concentration of 108 units of colony-makers for ml (UFC/ml) and 1 ml was inoculated through intra-peritoneal via. Forty-eight rats were divided into four groups: control, laparotomy, pneumoperitoneum with 10 mmHg and pneumoperitoneum with 20 mmHg of CO2. Procedures were performed 20 min after injection of the inoculum and lasted 30 min. Animals were sacrificed after six hours (Group 1) and 24 hours (Group 2). Samples of blood, liver and spleen were collected for radioactivity counting. Results: After six hours, indirect detection of the bacteria in different organs was uniform in all groups. After 24 hours, a larger detection of technetium was observed in the livers of animals of the group insufflated with 20 mmHg of CO2, when compared with those of control group (p<0.01). The other groups did not present statistically significant variations. Conclusions: The use of a higher intra-abdominal pressure was associated with a higher bacterial dissemination to the liver. The application of lower intra-abdominal pressures may be associated with a lower dissemination of the infectious status during laparoscopic approach of peritonitis status. (author)

  18. Utilization of CO2 in High Performance Building and Infrastructure Products

    Energy Technology Data Exchange (ETDEWEB)

    DeCristofaro, Nicholas [Solidia Technologies Inc., Piscataway, NJ (United States)

    2015-11-01

    The overall objective of DE-FE0004222 was to demonstrate that calcium silicate phases, in the form of either naturally-occuring minerals or synthetic compounds, could replace Portland cement in concrete manufacturing. The calcium silicate phases would be reacted with gaseous CO2 to create a carbonated concrete end-product. If successful, the project would offer a pathway to a significant reduction in the carbon footprint associated with the manufacture of cement and its use in concrete (approximately 816 kg of CO2 is emitted in the production of one tonne of Portland cement). In the initial phases of the Technical Evaluation, Rutgers University teamed with Solidia Technologies to demonstrate that natural wollastonite (CaSiO3), milled to a particle size distribution consistent with that of Portland cement, could indeed fit this bill. The use of mineral wollastonite as a cementitious material would potentially eliminate the CO2 emitted during cement production altogether, and store an additional 250 kg of CO2 during concrete curing. However, it was recognized that mineral wollastonite was not available in volumes that could meaningfully impact the carbon footprint associated with the cement and concrete industries. At this crucial juncture, DE-FE0004222 was redirected to use a synthetic version of wollastonite, hereafter referred to as Solidia Cement™, which could be manufactured in conventional cement making facilities. This approach enables the new cementitious material to be made using existing cement industry raw material supply chains, capital equipment, and distribution channels. It would also offer faster and more complete access to the concrete marketplace. The latter phases of the Technical Evaluation, conducted with Solidia Cement made in research rotary kilns, would demonstrate that industrially viable CO2-curing practices were possible. Prototypes of full-scale precast concrete products such as pavers, concrete masonry units, railroad ties, hollow

  19. CO2 Capture and Reuse

    International Nuclear Information System (INIS)

    Thambimuthu, K.; Gupta, M.; Davison, J.

    2003-01-01

    CO2 capture and storage including its utilization or reuse presents an opportunity to achieve deep reductions in greenhouse gas emissions from fossil energy use. The development and deployment of this option could significantly assist in meeting a future goal of achieving stabilization of the presently rising atmospheric concentration of greenhouse gases. CO2 capture from process streams is an established concept that has achieved industrial practice. Examples of current applications include the use of primarily, solvent based capture technologies for the recovery of pure CO2 streams for chemical synthesis, for utilization as a food additive, for use as a miscible agent in enhanced oil recovery operations and removal of CO2 as an undesired contaminant from gaseous process streams for the production of fuel gases such as hydrogen and methane. In these applications, the technologies deployed for CO2 capture have focused on gas separation from high purity, high pressure streams and in reducing (or oxygen deficient) environments, where the energy penalties and cost for capture are moderately low. However, application of the same capture technologies for large scale abatement of greenhouse gas emissions from fossil fuel use poses significant challenges in achieving (at comparably low energy penalty and cost) gas separation in large volume, dilute concentration and/or low pressure flue gas streams. This paper will focus on a review of existing commercial methods of CO2 capture and the technology stretch, process integration and energy system pathways needed for their large scale deployment in fossil fueled processes. The assessment of potential capture technologies for the latter purpose will also be based on published literature data that are both 'transparent' and 'systematic' in their evaluation of the overall cost and energy penalties of CO2 capture. In view of the of the fact that many of the existing commercial processes for CO2 capture have seen applications in

  20. Activated carbons prepared from hazelnut shells, walnut shells and peanut shells for high CO2 adsorption

    Directory of Open Access Journals (Sweden)

    Lewicka Katarzyna

    2017-06-01

    Full Text Available Research treats about producing activated carbons for CO2 capture from hazelnut shells (HN, walnut shells (WN and peanut shells (PN. Saturated solution of KOH was used as an activating agent in ratio 1:1. Samples were carbonized in the furnace in the range of temperatures 600°C–900°C. Properties of carbons were tested by N2 adsorption method, using BET equation, DFT method and volumetric CO2 adsorption method. With the increase of carbonization temperature specific surface area of studied samples increased. The largest surface area was calculated for samples carbonized at 900°C and the highest values of CO2 adsorption had samples: PN900 at 0°C (5.5 mmol/g and WN900 at 25°C (4.34 mmol/g. All of the samples had a well-developed microporous structure.

  1. High-throughput synthesis of mixed-metal electrocatalysts for CO2 reduction

    International Nuclear Information System (INIS)

    He, Jingfu; Dettelbach, Kevan E.; Li, Tengfei; Salvatore, Danielle A.; Berlinguette, Curtis P.

    2017-01-01

    The utilization of CO 2 as a feedstock requires fundamental breakthroughs in catalyst design. The efficiencies and activities of pure metal electrodes towards the CO 2 reduction reaction are established, but the corresponding data on mixed-metal systems are not as well developed. In this study we show that the near-infrared driven decomposition (NIRDD) of solution-deposited films of metal salts and subsequent electrochemical reduction offers the unique opportunity to form an array of mixed-metal electrocatalyst coatings with excellent control of the metal stoichiometries. This synthetic method enabled us to develop an empirical structure-property correlation to help inform the development of optimized CO 2 catalyst compositions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. BioCO2 - a multidisciplinary, biological approach using solar energy to capture CO2 while producing H2 and high value products.

    Science.gov (United States)

    Skjånes, Kari; Lindblad, Peter; Muller, Jiri

    2007-10-01

    Many areas of algae technology have developed over the last decades, and there is an established market for products derived from algae, dominated by health food and aquaculture. In addition, the interest for active biomolecules from algae is increasing rapidly. The need for CO(2) management, in particular capture and storage is currently an important technological, economical and global political issue and will continue to be so until alternative energy sources and energy carriers diminish the need for fossil fuels. This review summarizes in an integrated manner different technologies for use of algae, demonstrating the possibility of combining different areas of algae technology to capture CO(2) and using the obtained algal biomass for various industrial applications thus bringing added value to the capturing and storage processes. Furthermore, we emphasize the use of algae in a novel biological process which produces H(2) directly from solar energy in contrast to the conventional CO(2) neutral biological methods. This biological process is a part of the proposed integrated CO(2) management scheme.

  3. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... other risk factors, like diabetes, you may need treatment. How does high blood pressure affect pregnant women? A few women will get ... HIV, Birth Control Heart Health for Women Pregnancy Menopause More Women's Health ... High Blood Pressure--Medicines to Help You Women and Diabetes Heart ...

  4. High-pressure crystallography

    Science.gov (United States)

    Katrusiak, A.

    2008-01-01

    The history and development of high-pressure crystallography are briefly described and examples of structural transformations in compressed compounds are given. The review is focused on the diamond-anvil cell, celebrating its 50th anniversary this year, the principles of its operation and the impact it has had on high-pressure X-ray diffraction.

  5. Broadening of spectral lines of CO2, N2O , H2CO, HCN, and H2S by pressure of gases dominant in planetary atmospheres (H2, He and CO2)

    Science.gov (United States)

    Samuels, Shanelle; Gordon, Iouli; Tan, Yan

    2018-01-01

    HITRAN1,2 is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in planetary atmospheres. The goal of this project is to add to the potential of the HITRAN database towards the exploration of the planetary atmospheres by including parameters describing broadening of spectral lines by H2, CO2, and He. These spectroscopic data are very important for the study of the hydrogen and helium-rich atmospheres of gas giants as well as rocky planets with volcanic activities, including Venus and Mars, since their atmospheres are dominated by CO2. First step in this direction was accomplished by Wilzewski et al.3 where this was done for SO2, NH3, HF, HCl, OCS and C2H2. The molecules investigated in this work were CO2, N2O, H2CO, HCN and H2S. Line-broadening coefficients, line shifts and temperature-dependence exponents for transitions of these molecules perturbed by H2, CO2 and He have been assembled from available peer-reviewed experimental and theoretical sources. The data was evaluated and the database was populated with these data and their extrapolations/interpolations using semi-empirical models that were developed to this end.Acknowledgements: Financial support from NASA PDART grant NNX16AG51G and the Smithsonian Astrophysical Observatory Latino Initiative Program from the Latino Initiatives Pool, administered by the Smithsonian Latino Center is gratefully acknowledged.References: 1. HITRAN online http://hitran.org/2. Gordon, I.E., Rothman, L.S., Hill, C., Kochanov, R.V., Tan, Y., et al., 2017. The HITRAN2016 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transf. doi:10.1016/j.jqsrt.2017.06.0383. Wilzewski, J.S., Gordon, I.E., Kochanov, R. V., Hill, C., Rothman, L.S., 2016. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2. J. Quant. Spectrosc. Radiat

  6. Advanced Technologies for Monitoring CO2 Saturation and Pore Pressure in Geologic Formations: Linking the Chemical and Physical Effects to Elastic and Transport Properties

    Energy Technology Data Exchange (ETDEWEB)

    Mavko, G.; Vanorio, T.; Vialle, S.; Saxena, N.

    2014-03-31

    Ultrasonic P- and S-wave velocities were measured over a range of confining pressures while injecting CO2 and brine into the samples. Pore fluid pressure was also varied and monitored together with porosity during injection. Effective medium models were developed to understand the mechanisms and impact of observed changes and to provide the means for implementation of the interpretation methodologies in the field. Ultrasonic P- and S-wave velocities in carbonate rocks show as much as 20-50% decrease after injection of the reactive CO2-brine mixture; the changes were caused by permanent changes to the rock elastic frame associated with dissolution of mineral. Velocity decreases were observed under both dry and fluid-saturated conditions, and the amount of change was correlated with the initial pore fabrics. Scanning Electron Microscope images of carbonate rock microstructures were taken before and after injection of CO2-rich water. The images reveal enlargement of the pores, dissolution of micrite (micron-scale calcite crystals), and pitting of grain surfaces caused by the fluid- solid chemical reactivity. The magnitude of the changes correlates with the rock microtexture – tight, high surface area samples showed the largest changes in permeability and smallest changes in porosity and elastic stiffness compared to those in rocks with looser texture and larger intergranular pore space. Changes to the pore space also occurred from flow of fine particles with the injected fluid. Carbonates with grain-coating materials, such as residual oil, experienced very little permanent change during injection. In the tight micrite/spar cement component, dissolution is controlled by diffusion: the mass transfer of products and reactants is thus slow and the fluid is expected to be close to thermodynamical equilibrium with the calcite, leading to very little dissolution, or even precipitation. In the microporous rounded micrite and macropores, dissolution is controlled by

  7. High power CO2 laser development with AOM integration for ultra high-speed pulses

    Science.gov (United States)

    Bohrer, Markus; Vaupel, Matthias; Nirnberger, Robert; Weinberger, Bernhard; Jamalieh, Murad

    2017-01-01

    There is a 500 billion USD world market for packaging expected to grow to a trillion in 2030. Austria plays an important role world wide for high speed laser engraving applications — especially when it comes to high end solutions. Such high end solutions are fundamental for the production of print forms for the packaging and decorating industry (e. g. cans). They are additionally used for security applications (e. g. for printing banknotes), for the textile printing industry and for creating embossing forms (e. g. for the production of dashboards in the automotive industry). High speed, high precision laser engraving needs laser resonators with very stable laser beams (400 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench using hexapods, allowing to optimize the complete beam path with collimators and AOM. The major steps related to laser engraving of dry offset printing plates during the full workflow from the artists design to the printed result on an aluminum can is presented in this paper as well as laser characteristics, AOM integration and correlative CLSM and SEM investigation of the results.

  8. Cavitation-induced reactions in high-pressure carbon dioxide

    NARCIS (Netherlands)

    Kuijpers, M.W.A.; van Eck, D.; Kemmere, M.F.; Keurentjes, J.T.F.

    2002-01-01

    The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of

  9. Highly Stable Porous Covalent Triazine-Piperazine Linked Nanoflower as a Feasible Adsorbent for Flue Gas CO2 Capture

    KAUST Repository

    Das, Swapan Kumar; Wang, Xinbo; Ostwal, Mayur; Zhao, Yunfeng; Han, Yu; Lai, Zhiping

    2016-01-01

    robustness under acidic and basic medium and high thermal stability up to 773 K. The CTPP possess high surface area (779 m2/g) and single-component gas adsorption study exhibited enhanced CO2 and CH4 uptake of 3.48 mmol/g, 1.09 mmol/g, respectively at 273 K

  10. Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records

    Science.gov (United States)

    Martínez-Botí, M. A.; Foster, G. L.; Chalk, T. B.; Rohling, E. J.; Sexton, P. F.; Lunt, D. J.; Pancost, R. D.; Badger, M. P. S.; Schmidt, D. N.

    2015-02-01

    Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2.

  11. Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records.

    Science.gov (United States)

    Martínez-Botí, M A; Foster, G L; Chalk, T B; Rohling, E J; Sexton, P F; Lunt, D J; Pancost, R D; Badger, M P S; Schmidt, D N

    2015-02-05

    Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2.

  12. Behavioural disturbances in a temperate fish exposed to sustained high-CO2 levels.

    Directory of Open Access Journals (Sweden)

    Fredrik Jutfelt

    Full Text Available As atmospheric CO2 levels rise, the CO2 concentration in ocean surface waters increases through a process commonly referred to as ocean acidification. Recently, surprising behavioural modifications has been detected in the early life stages of tropical coral reef fish exposed to ocean acidification-relevant CO2 concentrations, but it has been unclear if this effect could occur in temperate waters. Here we show several severe behavioural disturbances, including effects on boldness, exploratory behaviour, lateralisation, and learning in a temperate fish, the three-spined stickleback (Gasterosteus aculeatus. The behavioural effects were consistent throughout the exposure period and increased in effect size with exposure time. We observed the effects on adult sticklebacks, a species known to be tolerant to other environmental stressors. Our findings suggest that behavioural abnormalities that stem from CO2 exposure are not restricted to sensitive tropical species or early life stages and may therefore affect fish on a global scale. The severity of disturbances and the possibility of a serious behavioural problem for fish across the globe is cause for concern.

  13. Absorption of CO2 laser light by a dense, high temperature plasma

    International Nuclear Information System (INIS)

    Peacock, N.J.; Forrest, M.J.; Morgan, P.D.; Offenberger, A.A.

    1977-01-01

    The interaction between a pulsed, CO 2 laser beam and the plasma produced in a plasma focus device is investigated theoretically and experimentally. The CO 2 laser radiation, directed orthogonal to the pinch axis and along the density gradient only weakly perturbs the focus since the radiation density of 30 J cm -3 (allowing for the Airy enhancement factor near the critical layer), is still less than the plasma thermal energy >=1 kJ cm -3 . On the contrary, the CO 2 laser beam is grossly affected by the plasma and absorption during the compressed pinch phase when the plasma frequency is much more complete than can be predicted by classical resistivity. Density fluctuations at the Langmuir frequency are measured directly for forward scattering from a probe, ruby laser beam. Since the wave numbers correspond to approximately 0.1 the Langmuir waves should appear as electron 'lines' in the scattered spectrum shifted by 427 A from the ruby laser wavelength. At low CO 2 laser pump intensity the electron wave intensity is close to the thermal level. As the pump is increased beyond a threshold of approximately 3x10 9 W/cm -2 (in vacuo) enhanced scattering is observed, reaching a factor of 30 above thermal. A WKB treatment of the electron-ion decay instability which takes into account the linear growth of waves at equal electron and ion temperatures and their convection in an inhomogeneous plasma is reasonably consistent with the observations

  14. Phytoplankton Do Not Produce Carbon-Rich Organic Matter in High CO2 Oceans

    Science.gov (United States)

    Kim, Ja-Myung; Lee, Kitack; Suh, Young-Sang; Han, In-Seong

    2018-05-01

    The ocean is a substantial sink for atmospheric carbon dioxide (CO2) released as a result of human activities. Over the coming decades the dissolved inorganic C concentration in the surface ocean is predicted to increase, which is expected to have a direct influence on the efficiency of C utilization (consumption and production) by phytoplankton during photosynthesis. Here we evaluated the generality of C-rich organic matter production by examining the elemental C:N ratio of organic matter produced under conditions of varying pCO2. The data used in this analysis were obtained from a series of pelagic in situ pCO2 perturbation studies that were performed in the diverse ocean regions and involved natural phytoplankton assemblages. The C:N ratio of the resulting particulate and dissolved organic matter did not differ across the range of pCO2 conditions tested. In particular, the ratio for particulate organic C and N was found to be 6.58 ± 0.05, close to the theoretical value of 6.6.

  15. Highly sensitive miniature fluidic flowmeter based on an FBG heated by Co2+-doped fiber

    NARCIS (Netherlands)

    Liu, Z.; Htein, L.; Cheng, L.K.; Martina, Q.; Jansen, R.; Tam, H.Y.

    2017-01-01

    In this paper, we present a miniature fluidic flow sensor based on a short fiber Bragg grating inscribed in a single mode fiber and heated by Co2+-doped multimode fibers. The proposed flow sensor was employed to measure the flow rates of oil and water, showing good sensitivity of 0.339 nm/(m/s) and

  16. Quantification of uncertainty associated with United States high resolution fossil fuel CO2 emissions: updates, challenges and future plans

    Science.gov (United States)

    Gurney, K. R.; Chandrasekaran, V.; Mendoza, D. L.; Geethakumar, S.

    2010-12-01

    The Vulcan Project has estimated United States fossil fuel CO2 emissions at the hourly time scale and at spatial scales below the county level for the year 2002. Vulcan is built from a wide variety of observational data streams including regulated air pollutant emissions reporting, traffic monitoring, energy statistics, and US census data. In addition to these data sets, Vulcan relies on a series of modeling assumptions and constructs to interpolate in space, time and transform non-CO2 reporting into an estimate of CO2 combustion emissions. The recent version 2.0 of the Vulcan inventory has produced advances in a number of categories with particular emphasis on improved temporal structure. Onroad transportation emissions now avail of roughly 5000 automated traffic count monitors allowing for much improved diurnal and weekly time structure in our onroad transportation emissions. Though the inventory shows excellent agreement with independent national-level CO2 emissions estimates, uncertainty quantification has been a challenging task given the large number of data sources and numerous modeling assumptions. However, we have now accomplished a complete uncertainty estimate across all the Vulcan economic sectors and will present uncertainty estimates as a function of space, time, sector and fuel. We find that, like the underlying distribution of CO2 emissions themselves, the uncertainty is also strongly lognormal with high uncertainty associated with a relatively small number of locations. These locations typically are locations reliant upon coal combustion as the dominant CO2 source. We will also compare and contrast Vulcan fossil fuel CO2 emissions estimates against estimates built from DOE fuel-based surveys at the state level. We conclude that much of the difference between the Vulcan inventory and DOE statistics are not due to biased estimation but mechanistic differences in supply versus demand and combustion in space/time.

  17. Understanding CO2 Plume Behavior and Basin-Scale Pressure Changes during Sequestration Projects through the use of Reservoir Fluid Modeling

    Science.gov (United States)

    Leetaru, H.E.; Frailey, S.M.; Damico, J.; Mehnert, E.; Birkholzer, J.; Zhou, Q.; Jordan, P.D.

    2009-01-01

    Large scale geologic sequestration tests are in the planning stages around the world. The liability and safety issues of the migration of CO2 away from the primary injection site and/or reservoir are of significant concerns for these sequestration tests. Reservoir models for simulating single or multi-phase fluid flow are used to understand the migration of CO2 in the subsurface. These models can also help evaluate concerns related to brine migration and basin-scale pressure increases that occur due to the injection of additional fluid volumes into the subsurface. The current paper presents different modeling examples addressing these issues, ranging from simple geometric models to more complex reservoir fluid models with single-site and basin-scale applications. Simple geometric models assuming a homogeneous geologic reservoir and piston-like displacement have been used for understanding pressure changes and fluid migration around each CO2 storage site. These geometric models are useful only as broad approximations because they do not account for the variation in porosity, permeability, asymmetry of the reservoir, and dip of the beds. In addition, these simple models are not capable of predicting the interference between different injection sites within the same reservoir. A more realistic model of CO2 plume behavior can be produced using reservoir fluid models. Reservoir simulation of natural gas storage reservoirs in the Illinois Basin Cambrian-age Mt. Simon Sandstone suggest that reservoir heterogeneity will be an important factor for evaluating storage capacity. The Mt. Simon Sandstone is a thick sandstone that underlies many significant coal fired power plants (emitting at least 1 million tonnes per year) in the midwestern United States including the states of Illinois, Indiana, Kentucky, Michigan, and Ohio. The initial commercial sequestration sites are expected to inject 1 to 2 million tonnes of CO2 per year. Depending on the geologic structure and

  18. Physiological basis for high CO2 tolerance in marine ectothermic animals: pre-adaptation through lifestyle and ontogeny?

    Directory of Open Access Journals (Sweden)

    M. Bleich

    2009-10-01

    Full Text Available Future ocean acidification has the potential to adversely affect many marine organisms. A growing body of evidence suggests that many species could suffer from reduced fertilization success, decreases in larval- and adult growth rates, reduced calcification rates, and even mortality when being exposed to near-future levels (year 2100 scenarios of ocean acidification. Little research focus is currently placed on those organisms/taxa that might be less vulnerable to the anticipated changes in ocean chemistry; this is unfortunate, as the comparison of more vulnerable to more tolerant physiotypes could provide us with those physiological traits that are crucial for ecological success in a future ocean. Here, we attempt to summarize some ontogenetic and lifestyle traits that lead to an increased tolerance towards high environmental pCO2. In general, marine ectothermic metazoans with an extensive extracellular fluid volume may be less vulnerable to future acidification as their cells are already exposed to much higher pCO2 values (0.1 to 0.4 kPa, ca. 1000 to 3900 μatm than those of unicellular organisms and gametes, for which the ocean (0.04 kPa, ca. 400 μatm is the extracellular space. A doubling in environmental pCO2 therefore only represents a 10% change in extracellular pCO2 in some marine teleosts. High extracellular pCO2 values are to some degree related to high metabolic rates, as diffusion gradients need to be high in order to excrete an amount of CO2 that is directly proportional to the amount of O2 consumed. In active metazoans, such as teleost fish, cephalopods and many brachyuran crustaceans, exercise induced increases in metabolic rate require an efficient ion-regulatory machinery for CO2 excretion and acid-base regulation, especially when anaerobic metabolism is involved and metabolic protons leak into the extracellular space. These ion-transport systems, which are located in highly developed gill epithelia, form the basis for

  19. Supercritical CO2 uptake by nonswelling phyllosilicates.

    Science.gov (United States)

    Wan, Jiamin; Tokunaga, Tetsu K; Ashby, Paul D; Kim, Yongman; Voltolini, Marco; Gilbert, Benjamin; DePaolo, Donald J

    2018-01-30

    Interactions between supercritical (sc) CO 2 and minerals are important when CO 2 is injected into geologic formations for storage and as working fluids for enhanced oil recovery, hydraulic fracturing, and geothermal energy extraction. It has previously been shown that at the elevated pressures and temperatures of the deep subsurface, scCO 2 alters smectites (typical swelling phyllosilicates). However, less is known about the effects of scCO 2 on nonswelling phyllosilicates (illite and muscovite), despite the fact that the latter are the dominant clay minerals in deep subsurface shales and mudstones. Our studies conducted by using single crystals, combining reaction (incubation with scCO 2 ), visualization [atomic force microscopy (AFM)], and quantifications (AFM, X-ray photoelectron spectroscopy, X-ray diffraction, and off-gassing measurements) revealed unexpectedly high CO 2 uptake that far exceeded its macroscopic surface area. Results from different methods collectively suggest that CO 2 partially entered the muscovite interlayers, although the pathways remain to be determined. We hypothesize that preferential dissolution at weaker surface defects and frayed edges allows CO 2 to enter the interlayers under elevated pressure and temperature, rather than by diffusing solely from edges deeply into interlayers. This unexpected uptake of CO 2 , can increase CO 2 storage capacity by up to ∼30% relative to the capacity associated with residual trapping in a 0.2-porosity sandstone reservoir containing up to 18 mass % of illite/muscovite. This excess CO 2 uptake constitutes a previously unrecognized potential trapping mechanism. Copyright © 2018 the Author(s). Published by PNAS.

  20. Reservoir Characterization and CO2 Plume Migration Modeling Based on Bottom-hole Pressure Data: An Example from the AEP Mountaineer Geological Storage Project

    Science.gov (United States)

    Mishra, Srikanta; Kelley, Mark; Oruganti, YagnaDeepika; Bhattacharya, Indra; Spitznogle, Gary

    2014-05-01

    We present an integrated approach for formation permeability estimation, front tracking, reservoir model calibration, and plume migration modeling based on injection rate and down-hole pressure data from CO2 geologic sequestration projects. The data are taken from the 20 MW CO2 capture and storage project at American Electric Power's Mountaineer Plant in West Virginia, USA. The Mountaineer CO2 injection system consists of two injection wells - one in the Copper Ridge Dolomite formation and one in the Rose Run sandstone formation, and three deep observation wells that were operational between October 2009 and May 2011. Approximately 27000 MT and 10000 MT were injected into the Copper Ridge dolomite formation and Rose Run sandstone formation, respectively. A wealth of pressure and rate data from injection and observation wells is available covering a series of injection and pressure falloff events. The methodology developed and applied for interpreting and integrating the data during reservoir analysis and modeling from the Rose Run formation is the subject of this paper. For the analysis of transient pressure data at the injection and observation wells, the CO2 storage reservoir is conceptualized as a radial composite system, where the inner (invaded) zone consists of both supercritical CO2 and brine, and the outer (uninvaded) zone consists of undisturbed brine. Using established analytical solutions for analyzing fluid injection problems in the petroleum reservoir engineering literature, we show how the late-time pressure derivative response from both injection and observation wells will be identical - reflecting the permeability-thickness product of the undisturbed brine-filled formation. We also show how the expanding CO2 plume affects the "effective" compressibility that can be estimated by history matching injection-falloff data and how this can be used to develop a relationship between the plume radius and "effective" compressibility. This provides a novel non

  1. Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane

    Science.gov (United States)

    Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

    2017-01-01

    We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30-200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO2 and 99% N2. Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanoparticles in room temperature. The MOF nanoparticles of 100-200 nm in size displayed higher surface area and adsorption capacity comparing to that of 30-60 nm in size. Nanofibrous membrane was produced by electrospinning of MOF blended PAN solution followed by electrospraying of additional MOF nanoparticles. This yielded uniform MOF deposition on nanofibers, occurred due to electrostatic attraction between highly charged nanoparticles and conductive nanofibers. A test bench for real-time CO2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO2 adsorption for approximately 2 h. Thermogravimetric analysis (TGA) of the membrane showed the thermal stability of the MOF and PAN up to 290 and 425 °C, respectively.

  2. A highly selective copper-indium bimetallic electrocatalyst for the electrochemical reduction of aqueous CO2to CO

    KAUST Repository

    Rasul, Shahid

    2014-12-23

    The challenge in the electrochemical reduction of aqueous carbon dioxide is in designing a highly selective, energy-efficient, and non-precious-metal electrocatalyst that minimizes the competitive reduction of proton to form hydrogen during aqueous CO2 conversion. A non-noble metal electrocatalyst based on a copper-indium (Cu-In) alloy that selectively converts CO2 to CO with a low overpotential is reported. The electrochemical deposition of In on rough Cu surfaces led to Cu-In alloy surfaces. DFT calculations showed that the In preferentially located on the edge sites rather than on the corner or flat sites and that the d-electron nature of Cu remained almost intact, but adsorption properties of neighboring Cu was perturbed by the presence of In. This preparation of non-noble metal alloy electrodes for the reduction of CO2 provides guidelines for further improving electrocatalysis.

  3. Low to High Spin-State Transition Induced by Charge Ordering in Antiferromagnetic YBaCo2O5

    International Nuclear Information System (INIS)

    Vogt, T.; Woodward, P. M.; Karen, P.; Hunter, B. A.; Henning, P.; Moodenbaugh, A. R.

    2000-01-01

    The oxygen-deficient double perovskite YBaCo 2 O 5 , containing corner-linked CoO 5 square pyramids as principal building units, undergoes a paramagnetic to antiferromagnetic spin ordering at 330 K. This is accompanied by a tetragonal to orthorhombic distortion. Below 220 K orbital ordering and long-range Co 2+ /Co 3+ charge ordering occur as well as a change in the Co 2+ spin state from low to high spin. This transition is shown to be very sensitive to the oxygen content of the sample. To our knowledge this is the first observation of a spin-state transition induced by long-range orbital and charge ordering. (c) 2000 The American Physical Society

  4. High nitrate to phosphorus regime attenuates negative effects of rising pCO2 on total population carbon accumulation

    Directory of Open Access Journals (Sweden)

    S. A. Krug

    2012-03-01

    Full Text Available The ongoing rise in atmospheric pCO2 and consequent increase in ocean acidification have direct effects on marine calcifying phytoplankton, which potentially alters carbon export. To date it remains unclear, firstly, how nutrient regime, in particular by coccolithophores preferred phosphate limitation, interacts with pCO2 on particulate carbon accumulation; secondly, how direct physiological responses on the cellular level translate into total population response. In this study, cultures of Emiliania huxleyi were full-factorially exposed to two different N:P regimes and three different pCO2 levels. Cellular biovolume and PIC and POC content significantly declined in response to pCO2 in both nutrient regimes. Cellular PON content significantly increased in the Redfield treatment and decreased in the high N:P regime. Cell abundance significantly declined in the Redfield and remained constant in the high N:P regime. We hypothesise that in the high N:P regime severe phosphorous limitation could be compensated either by reduced inorganic phosphorous demand and/or by enzymatic uptake of organic phosphorous. In the Redfield regime we suggest that enzymatic phosphorous uptake to supplement enhanced phosphorous demand with pCO2 was not possible and thus cell abundance declined. These hypothesised different physiological responses of E. huxleyi among the nutrient regimes significantly altered population carrying capacities along the pCO2 gradient. This ultimately led to the attenuated total population response in POC and PIC content and biovolume to increased pCO2 in the high N:P regime. Our results point to the fact that the physiological (i.e. cellular PIC and POC response to ocean acidification cannot be linearly extrapolated to total population response and thus carbon export. It is therefore necessary to consider both effects of nutrient limitation on cell physiology and their consequences for population size when predicting the influence of

  5. Hierarchically porous Ni monolith@branch-structured NiCo2O4 for high energy density supercapacitors

    Directory of Open Access Journals (Sweden)

    Mengjie Xu

    2016-06-01

    Full Text Available A variety of NiCo2O4 nanostrucutures ranging from nanowire to nanoplate and branched structures were successfully prepared via a simple hydrothermal process. The experimental results show that NiCo2O4 with branched structures possesses the best overall electrochemical performance. The improvement of energy density was explored in terms of hierarchically three-dimensional (3D metal substrates and a high specific area capacitance, and area energy density is obtained with hierarchically porous Ni monolith synthesized through a controlled combustion procedure.

  6. High Blood Pressure

    Science.gov (United States)

    ... kidney disease, diabetes, or metabolic syndrome Read less Unhealthy lifestyle habits Unhealthy lifestyle habits can increase the risk of high blood pressure. These habits include: Unhealthy eating patterns, such as eating too much sodium ...

  7. High Blood Pressure

    Science.gov (United States)

    ... factors Diabetes High blood pressure Family history Obesity Race/ethnicity Full list of causes and risk factors ... give Give monthly Memorials and tributes Donate a car Donate gently used items Stock donation Workplace giving ...

  8. Changing noise levels in a high CO2/lower pH ocean

    Science.gov (United States)

    Brewer, P. G.; Hester, K. C.; Peltzer, E. T.; Kirkwood, W. J.

    2008-12-01

    We show that ocean acidification from fossil fuel CO2 invasion and from increased respiration/reduced ventilation, has significantly reduced ocean sound absorption and thus increased ocean noise levels in the kHz frequency range. Below 10 kHz, sound absorption occurs due to well known chemical relaxations in the B(OH)3/B(OH)4- and HCO3-/CO32- systems. The pH dependence of these chemical relaxations results in decreased sound absorption (α = dB/km) as the ocean becomes more acidic from increased CO2 levels. The scale of surface ocean pH change today from the +105 ppmv change in atmospheric CO2 is about - 0.12 pH, resulting in frequency dependent decreases in sound absorption that now exceed 12% over pre- industrial. Under reasonable projections of future fossil fuel CO2 emissions and other sources a pH change of 0.3 units or more can be anticipated by mid-century, resulting in a decrease in α by almost 40%. Increases in water temperature have a smaller effect but also contribute to decreased sound absorption. Combining a lowering of 0.3 pH units with an increase of 3°C, α will decrease further to almost 45%. Ambient noise levels in the ocean within the auditory range critical for environmental, military, and economic interests are set to increase significantly due to the combined effects of decreased absorption and increasing sources from mankind's activities. Incorporation of sound absorption in modeling future ocean scenarios (R. Zeebe, personal communication) and long-term monitoring possibly with the aid of modern cabled observatories can give insights in how ocean noise will continue to change and its effect on groups such as marine mammals which communicate in the affected frequency range.

  9. High net CO2 and CH4 release at a eutrophic shallow lake on a formerly drained fen

    Science.gov (United States)

    Franz, Daniela; Koebsch, Franziska; Larmanou, Eric; Augustin, Jürgen; Sachs, Torsten

    2016-05-01

    Drained peatlands often act as carbon dioxide (CO2) hotspots. Raising the groundwater table is expected to reduce their CO2 contribution to the atmosphere and revitalise their function as carbon (C) sink in the long term. Without strict water management rewetting often results in partial flooding and the formation of spatially heterogeneous, nutrient-rich shallow lakes. Uncertainties remain as to when the intended effect of rewetting is achieved, as this specific ecosystem type has hardly been investigated in terms of greenhouse gas (GHG) exchange. In most cases of rewetting, methane (CH4) emissions increase under anoxic conditions due to a higher water table and in terms of global warming potential (GWP) outperform the shift towards CO2 uptake, at least in the short term.Based on eddy covariance measurements we studied the ecosystem-atmosphere exchange of CH4 and CO2 at a shallow lake situated on a former fen grassland in northeastern Germany. The lake evolved shortly after flooding, 9 years previous to our investigation period. The ecosystem consists of two main surface types: open water (inhabited by submerged and floating vegetation) and emergent vegetation (particularly including the eulittoral zone of the lake, dominated by Typha latifolia). To determine the individual contribution of the two main surface types to the net CO2 and CH4 exchange of the whole lake ecosystem, we combined footprint analysis with CH4 modelling and net ecosystem exchange partitioning.The CH4 and CO2 dynamics were strikingly different between open water and emergent vegetation. Net CH4 emissions from the open water area were around 4-fold higher than from emergent vegetation stands, accounting for 53 and 13 g CH4 m-2 a-1 respectively. In addition, both surface types were net CO2 sources with 158 and 750 g CO2 m-2 a-1 respectively. Unusual meteorological conditions in terms of a warm and dry summer and a mild winter might have facilitated high respiration rates. In sum, even after 9

  10. A high resolution interferometric method to measure local swelling due to CO2 exposure in coal and shale

    NARCIS (Netherlands)

    Pluymakers, A.; Liu, J.; Kohler, F.; Renard, F.; Dysthe, D.

    2018-01-01

    We present an experimental method to study time-dependent, CO2-induced, local topography changes in mm-sized composite samples, plus results showing heterogeneous swelling of coal and shale on the nano- to micrometer scale. These results were obtained using high resolution interferometry

  11. High-pressure tritium

    International Nuclear Information System (INIS)

    Coffin, D.O.

    1976-01-01

    Some solutions to problems of compressing and containing tritium gas to 200 MPa at 700 0 K are discussed. The principal emphasis is on commercial compressors and high-pressure equipment that can be easily modified by the researcher for safe use with tritium. Experience with metal bellows and diaphragm compressors has been favorable. Selection of materials, fittings, and gauges for high-pressure tritium work is also reviewed briefly

  12. Development of a Novel Gas Pressurized Process-Based Technology for CO2 Capture from Post-Combustion Flue Gases Preliminary Year 1 Techno-Economic Study Results and Methodology for Gas Pressurized Stripping Process

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shiaoguo

    2013-03-01

    supercritical PC plant with 90% CO2 capture. This plant has the same boiler firing rate and superheated high pressure steam generation as the DOE/NETL report’s Case 12 PC plant. However, due to the difference in performance between the GPS-based PCC and the MEA-based CO2 absorption technology, the net power output of this plant may not be exactly at 550 MWe.

  13. Inverse modeling of ground surface uplift and pressure with iTOUGH-PEST and TOUGH-FLAC: The case of CO2 injection at In Salah, Algeria

    Science.gov (United States)

    Rinaldi, Antonio P.; Rutqvist, Jonny; Finsterle, Stefan; Liu, Hui-Hai

    2017-11-01

    Ground deformation, commonly observed in storage projects, carries useful information about processes occurring in the injection formation. The Krechba gas field at In Salah (Algeria) is one of the best-known sites for studying ground surface deformation during geological carbon storage. At this first industrial-scale on-shore CO2 demonstration project, satellite-based ground-deformation monitoring data of high quality are available and used to study the large-scale hydrological and geomechanical response of the system to injection. In this work, we carry out coupled fluid flow and geomechanical simulations to understand the uplift at three different CO2 injection wells (KB-501, KB-502, KB-503). Previous numerical studies focused on the KB-502 injection well, where a double-lobe uplift pattern has been observed in the ground-deformation data. The observed uplift patterns at KB-501 and KB-503 have single-lobe patterns, but they can also indicate a deep fracture zone mechanical response to the injection. The current study improves the previous modeling approach by introducing an injection reservoir and a fracture zone, both responding to a Mohr-Coulomb failure criterion. In addition, we model a stress-dependent permeability and bulk modulus, according to a dual continuum model. Mechanical and hydraulic properties are determined through inverse modeling by matching the simulated spatial and temporal evolution of uplift to InSAR observations as well as by matching simulated and measured pressures. The numerical simulations are in agreement with both spatial and temporal observations. The estimated values for the parameterized mechanical and hydraulic properties are in good agreement with previous numerical results. In addition, the formal joint inversion of hydrogeological and geomechanical data provides measures of the estimation uncertainty.

  14. One-pot synthetic method to prepare highly N-doped nanoporous carbons for CO2 adsorption

    International Nuclear Information System (INIS)

    Meng, Long-Yue; Park, Soo-Jin

    2014-01-01

    A one-pot synthetic method was used for the preparation of nanoporous carbon containing nitrogen from polypyrrole (PPY) using NaOH as the activated agent. The activation process was carried out under set conditions (NaOH/PPY = 2 and NaOH/PPY = 4) at different temperatures in 600–900 °C for 2 h. The effect of the activation conditions on the pore structure, surface functional groups and CO 2 adsorption capacities of the prepared N-doped activated carbons was examined. The carbon was analyzed by X-ray photoelectron spectroscopy (XPS), N2/77 K full isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The CO 2 adsorption capacity of the N-doped activated carbon was measured at 298 K and 1 bar. By dissolving the activation agents, the N-doped activated carbon exhibited high specific surface areas (755–2169 m 2 g −1 ) and high pore volumes (0.394–1.591 cm 3 g −1 ). In addition, the N-doped activated carbons contained a high N content at lower activation temperatures (7.05 wt.%). The N-doped activated carbons showed a very high CO 2 adsorption capacity of 177 mg g −1 at 298 K and 1 bar. The CO 2 adsorption capacity was found to be dependent on the microporosity and N contents. - Highlights: • A one-pot synthetic method was used for the preparation of N-doped nanoporous carbons. • Polypyrrole (PPY) were activated with NaOH under set conditions (NaOH/PPY = 2 and 4). • N-doped activated carbon exhibited high specific surface areas (2169 m 2 g −1 ). • The carbons showed a very high CO 2 adsorption capacity of 177 mg g −1 at 298 K

  15. Coal gasification integration with solid oxide fuel cell and chemical looping combustion for high-efficiency power generation with inherent CO2 capture

    International Nuclear Information System (INIS)

    Chen, Shiyi; Lior, Noam; Xiang, Wenguo

    2015-01-01

    Highlights: • A novel power system integrating coal gasification with SOFC and chemical looping combustion. • The plant net power efficiency reaches 49.8% with complete CO 2 separation. • Energy and exergy analysis of the entire plant is conducted. • Sensitivity analysis shows a nearly constant power output when SOFC temperature and pressure vary. • NiO oxygen carrier shows higher plant efficiency than using Fe 2 O 3 and CuO. - Abstract: Since solid oxide fuel cells (SOFC) produce electricity with high energy conversion efficiency, and chemical looping combustion (CLC) is a process for fuel conversion with inherent CO 2 separation, a novel combined cycle integrating coal gasification, solid oxide fuel cell, and chemical looping combustion was configured and analyzed. A thermodynamic analysis based on energy and exergy was performed to investigate the performance of the integrated system and its sensitivity to major operating parameters. The major findings include that (1) the plant net power efficiency reaches 49.8% with ∼100% CO 2 capture for SOFC at 900 °C, 15 bar, fuel utilization factor = 0.85, fuel reactor temperature = 900 °C and air reactor temperature = 950 °C, using NiO as the oxygen carrier in the CLC unit. (2) In this parameter neighborhood the fuel utilization factor, the SOFC temperature and SOFC pressure have small effects on the plant net power efficiency because changes in pressure and temperature that increase the power generation by the SOFC tend to decrease the power generation by the gas turbine and steam cycle, and v.v.; an advantage of this system characteristic is that it maintains a nearly constant power output even when the temperature and pressure vary. (3) The largest exergy loss is in the gasification process, followed by those in the CO 2 compression and the SOFC. (4) Compared with the CLC Fe 2 O 3 and CuO oxygen carriers, NiO results in higher plant net power efficiency. To the authors’ knowledge, this is the first

  16. Concentration of phenolic compounds is increased in lettuce grown under high light intensity and elevated CO2.

    Science.gov (United States)

    Pérez-López, Usue; Sgherri, Cristina; Miranda-Apodaca, Jon; Micaelli, Francesco; Lacuesta, Maite; Mena-Petite, Amaia; Quartacci, Mike Frank; Muñoz-Rueda, Alberto

    2018-02-01

    The present study was focused on lettuce, a widely consumed leafy vegetable for the large number of healthy phenolic compounds. Two differently-pigmented lettuce cultivars, i.e. an acyanic-green leaf cv. and an anthocyanic-red one, were grown under high light intensity or elevated CO 2 or both in order to evaluate how environmental conditions may affect the production of secondary phenolic metabolites and, thus, lettuce quality. Mild light stress imposed for a short time under ambient or elevated CO 2 concentration increased phenolics compounds as well as antioxidant capacity in both lettuce cvs, indicating how the cultivation practice could enhance the health-promoting benefits of lettuce. The phenolic profile depended on pigmentation and the anthocyanic-red cv. always maintained a higher phenolic amount as well as antioxidant capacity than the acyanic-green one. In particular, quercetin, quercetin-3-O-glucuronide, kaempferol, quercitrin and rutin accumulated under high light or high CO 2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO 2 . In both cvs total free and conjugated phenolic acids maintained higher values under all altered environmental conditions, whereas luteolin reached significant amounts when both stresses were administered together, indicating, in this last case, that the enzymatic regulation of the flavonoid synthesis could be differently affected, the synthesis of flavones being favored. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Randomized trial of low versus high carbon dioxide insufflation pressures in posterior retroperitoneoscopic adrenalectomy.

    Science.gov (United States)

    Fraser, Sheila; Norlén, Olov; Bender, Kyle; Davidson, Joanne; Bajenov, Sonya; Fahey, David; Li, Shawn; Sidhu, Stan; Sywak, Mark

    2018-05-01

    Posterior retroperitoneoscopic adrenalectomy has gained widespread acceptance for the removal of benign adrenal tumors. Higher insufflation pressures using carbon dioxide (CO 2 ) are required, although the ideal starting pressure is unclear. This prospective, randomized, single-blinded, study aims to compare physiologic differences with 2 different CO 2 insufflation pressures during posterior retroperitoneoscopic adrenalectomy. Participants were randomly assigned to a starting insufflation pressure of 20 mm Hg (low pressure) or 25 mm Hg (high pressure). The primary outcome measure was partial pressure of arterial CO 2 at 60 minutes. Secondary outcomes included end-tidal CO 2 , arterial pH, blood pressure, and peak airway pressure. Breaches of protocol to change insufflation pressure were permitted if required and were recorded. A prospective randomized trial including 31 patients (low pressure: n = 16; high pressure: n = 15) was undertaken. At 60 minutes, the high pressure group had greater mean partial pressure of arterial CO 2 (64 vs 50 mm Hg, P = .003) and end-tidal CO 2 (54 vs 45 mm Hg, P = .008) and a lesser pH (7.21 vs 7.29, P = .0005). There were no significant differences in base excess, peak airway pressure, operative time, or duration of hospital stay. Clinically indicated protocol breaches were more common in the low pressure than the high pressure group (8 vs 3, P = .03). In posterior retroperitoneoscopic adrenalectomy, greater insufflation pressures are associated with greater partial pressure of arterial CO 2 and end-tidal CO 2 and lesser pH at 60 minutes, be significant. Commencing with lesser CO 2 insufflation pressures decreases intraoperative acidosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Development of experimental structure and influence of high CO2 concentration in maize cro Desenvolvimento de estrutura experimentale influências da alta concentração de CO2 na cultura do milho

    Directory of Open Access Journals (Sweden)

    João B. Lopes da Silva

    2012-04-01

    Full Text Available Maize is a C4 plant that shows few or no response to high [CO2]. Thus, this study aimed to analyze the photosynthetic rate and yield of maize under high [CO2] and develop open-top chambers (OTC to create an atmosphere enriched with CO2. The experiment was conducted between October 2008 and March 2009. The OTCs were developed in modular scheme. Measurement of photosynthetic rates, transpiration, stomata conductance, grain yield and dry matter were performed. The experimental design was randomized blocks with four replications and three treatments: P1 - plants grown in OTC with 700 ppm [CO2], P2 - plants grown in OTC with environmental [CO2], and P3 - control, cultivated in open field. The results were analyzed by ANOVA and Tukey's test (PrO milho é uma planta C4 que apresenta pouca, ou nenhuma, resposta às elevadas [CO2]; assim, neste trabalho, objetivou-se analisar respostas fisiológicas e produtivas da cultura do milho sob alta [CO2], e desenvolver câmaras de topo aberto (CTA para criar uma atmosfera enriquecida com CO2. O experimento foi conduzido entre outubro de 2008 e março de 2009. As CTAs foram desenvolvidas em esquema modular. Foram realizadas medições da taxa fotossintética, transpiração, condutância estomática, produção de grãos e matéria seca. O delineamento experimental foi em blocos casualizados, com quatro repetições e três tratamentos: P1 - plantas cultivadas em CTA a [CO2] de 700ppm; P2 - plantas cultivadas em CTAcom [CO2] ambiente; e P3 -plantas cultivadas em campo aberto, testemunhas. Os resultados obtidos foram submetidos à análise de variância e teste de Tukey (Pr<0,05. As câmaras reduzem em 25% a Radiação Fotossinteticamente Ativa e aumentam a temperatura do ar e das folhas, em relação ao ambiente externo. As plantas sob alta [CO2] (P1 apresentaram as maiores taxas fotossintéticas e as menores condutâncias estomáticas e transpiração. O peso total dos grãos (g e a matéria seca da parte a

  19. High resolution numerical investigation on the effect of convective instability on long term CO2 storage in saline aquifers

    International Nuclear Information System (INIS)

    Lu, C; Lichtner, P C

    2007-01-01

    CO 2 sequestration (capture, separation, and long term storage) in various geologic media including depleted oil reservoirs, saline aquifers, and oceanic sediments is being considered as a possible solution to reduce green house gas emissions. Dissolution of supercritical CO 2 in formation brines is considered an important storage mechanism to prevent possible leakage. Accurate prediction of the plume dissolution rate and migration is essential. Analytical analysis and numerical experiments have demonstrated that convective instability (Rayleigh instability) has a crucial effect on the dissolution behavior and subsequent mineralization reactions. Global stability analysis indicates that a certain grid resolution is needed to capture the features of density-driven fingering phenomena. For 3-D field scale simulations, high resolution leads to large numbers of grid nodes, unfeasible for a single workstation. In this study, we investigate the effects of convective instability on geologic sequestration of CO 2 by taking advantage of parallel computing using the code PFLOTRAN, a massively parallel 3-D reservoir simulator for modeling subsurface multiphase, multicomponent reactive flow and transport based on continuum scale mass and energy conservation equations. The onset, development and long-term fate of a supercritical CO 2 plume will be resolved with high resolution numerical simulations to investigate the rate of plume dissolution caused by fingering phenomena

  20. High Fidelity Computational Analysis of CO2 Trapping at Pore Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vinod

    2013-07-13

    With an alarming rise in carbon dioxide (CO2) emission from anthropogenic sources, CO2 sequestration has become an attractive choice to mitigate the emission. Some popular storage media for CO{sub 2} are oil reservoirs, deep coal-bed, and deep oceanic-beds. These have been used for the long term CO{sub 2} storage. Due to special lowering viscosity and surface tension property of CO{sub 2}, it has been widely used for enhanced oil recovery. The sites for CO{sub 2} sequestration or enhanced oil recovery mostly consist of porous rocks. Lack of knowledge of molecular mobility under confinement and molecule-surface interactions between CO2 and natural porous media results in generally governed by unpredictable absorption kinetics and total absorption capacity for injected fluids, and therefore, constitutes barriers to the deployment of this technology. Therefore, it is important to understand the flow dynamics of CO{sub 2} through the porous microstructures at the finest scale (pore-scale) to accurately predict the storage potential and long-term dynamics of the sequestered CO{sub 2}. This report discusses about pore-network flow modeling approach using variational method and analyzes simulated results this method simulations at pore-scales for idealized network and using Berea Sandstone CT scanned images. Variational method provides a promising way to study the kinetic behavior and storage potential at the pore scale in the presence of other phases. The current study validates variational solutions for single and two-phase Newtonian and single phase non-Newtonian flow through angular pores for special geometries whose analytical and/or empirical solutions are known. The hydraulic conductance for single phase flow through a triangular duct was also validated against empirical results derived from lubricant theory.

  1. Development of Advanced High Strength Steel for Improved Vehicle Safety, Fuel Efficiency and CO2 Emission

    Science.gov (United States)

    Kumar, Satendra; Singhai, Mrigandra; Desai, Rahul; Sam, Srimanta; Patra, Pradip Kumar

    2016-10-01

    Global warming and green house gas emissions are the major issues worldwide and their impacts are clearly visible as a record high temperatures, rising sea, and severe `flooding and droughts'. Motor vehicles considered as a major contributor on global warming due to its green house gas emissions. Hence, the automobile industries are under tremendous pressure from government and society to reduce green house gas emission to maximum possible extent. In present work, Dual Phase steel with boron as microalloying is manufactured using thermo-mechanical treatment during hot rolling. Dual phase steel with boron microalloying improved strength by near about 200 MPa than dual phase steel without boron. The boron added dual phase steel can be used for manufacturing stronger and a lighter vehicle which is expected to perform positively on green house gas emissions. The corrosion resistance behavior is also improved with boron addition which would further increase the life cycle of the vehicle even under corrosive atmosphere.

  2. CO2 laser-fabricated cladding light strippers for high-power fiber lasers and amplifiers.

    Science.gov (United States)

    Boyd, Keiron; Simakov, Nikita; Hemming, Alexander; Daniel, Jae; Swain, Robert; Mies, Eric; Rees, Simon; Andrew Clarkson, W; Haub, John

    2016-04-10

    We present and characterize a simple CO2 laser processing technique for the fabrication of compact all-glass optical fiber cladding light strippers. We investigate the cladding light loss as a function of radiation angle of incidence and demonstrate devices in a 400 μm diameter fiber with cladding losses of greater than 20 dB for a 7 cm device length. The core losses are also measured giving a loss of cladding light stripping of a 300 W laser diode with minimal heating of the fiber coating and packaging adhesives.

  3. Alignment system for large high-power CO2 laser fusion systems

    International Nuclear Information System (INIS)

    Bausman, M.D.; Liberman, I.; Manning, J.P.; Singer, S.

    1977-01-01

    Aligning a pulsed CO 2 laser fusion system involves control systems which insure that the centers of beams follow a prescribed path to within 1 mm, that the pointing of the beams is correct to approximately 20 microradians, and that focal spot at the location of the experimental fusion target be placed to accuracies of 10 to 20 micrometers laterally and approximately 50 micrometers axially. These alignments are accomplished by a variety of sensing techniques which include thermal pinholes and quadrant detectors, Seebeck effect silicon detectors, and imaging autocollimating Hartmann test procedures employing ir vidicon systems

  4. High efficiency metal marking with CO2 laser and glass marking with excimer laser

    DEFF Research Database (Denmark)

    Bastue, Jens; Olsen, Flemmming Ove

    1997-01-01

    with a thoroughly tested ray-tracing model is presented and compared with experimental results. Special emphasis is put on two different applications namely marking in metal with TEA-CO2 laser and marking in glass with excimer laser. The results are evaluated on the basis of the achievable energy enhancement......Today, mask based laser materials processing and especially marking is widely used. However, the energy efficiency in such processes is very low [1].This paper gives a review of the results, that may be obtained using the energy enhancing technique [1]. Results of simulations performed...

  5. Deuterium high pressure target

    International Nuclear Information System (INIS)

    Perevozchikov, V.V.; Yukhimchuk, A.A.; Vinogradov, Yu.I.

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm 3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  6. Simulation and initial experiments of a high power pulsed TEA CO2 laser

    Science.gov (United States)

    Torabi, R.; Saghafifar, H.; Koushki, A. M.; Ganjovi, A. A.

    2016-01-01

    In this paper, the output characteristics of a UV pin array pre-ionized TEA CO2 laser have been simulated and compared with the associated experimental data. In our simulation, a new theoretical model has been improved for transient behavior analysis of the discharge current pulse. The laser discharge tube was modeled by a nonlinear RLC electric circuit as a real model for electron density calculation. This model was coupled with a six-temperature model (6TM) in order to simulation dynamic emission processes of the TEA CO2 laser. The equations were solved numerically by the fourth order Runge-Kutta numerical method and some important variables such as current and voltage of the main discharge, resistance of the plasma column and electron density in the main discharge region, were calculated as functions of time. The effects of non-dissociation factor, rotational quantum number and output coupler reflectivity were also studied theoretically. The experimental and simulation results are in good agreement.

  7. Fabrication and Characterization of Polyimide-CNTs hybrid membrane to enhance high performance CO2 separation

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2015-03-01

    Full Text Available This study investigates the CO2 separation performance of a hybrid membranes flat sheet based on polyimide incorporated with carbon nanotubes (CNTs particles. CNTs was selected and its loading were a 1 wt% in total solid. The hybrid composite membranes were fabricated in order to increase their separation performance for the gaseous mixture of CO2 and CH4. Hybrid Composite  membrane incorporated carbon nanotubes were mannufactured  by the dry-wet phase inversion technique using flat sheet membrane casting machine system,  in which the CNTs were embedded into the polyimide membrane and the resulting membranes were characterized. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Sieve-in-a-cage’ morphology observed shows the poor adhesion between polymer and unmodified CNT. The results revealed that the good multi-wall carbon nanotubes dispersion leads to enhanced gas permeation properties. It is also concluded that addition of carbon nanotubes particles into the matrix of Polyimide polymer has significant effect on the membrane structure and properties.

  8. Heterogeneous NiCo2O4@polypyrrole core/sheath nanowire arrays on Ni foam for high performance supercapacitors

    Science.gov (United States)

    Hu, Jing; Li, Minchan; Lv, Fucong; Yang, Mingyang; Tao, Pengpeng; Tang, Yougen; Liu, Hongtao; Lu, Zhouguang

    2015-10-01

    A novel heterogeneous NiCo2O4@PPy core/sheath nanowire arrays are directly grown on Ni foam involving three facile steps, hydrothermal synthesis and calcination of NiCo2O4 nanowire arrays and subsequent in-situ oxidative polymerization of polypyrrole (PPy). When investigated as binder- and conductive additive-free electrodes for supercapacitors (SCs) in 6 M KOH, the NiCo2O4@PPy core/sheath nanowire arrays exhibit high areal capacitance of 3.49 F cm-2 at a discharge current density of 5 mA cm-2, which is almost 1.5 times as much as the pristine NiCo2O4 (2.30 F cm-2). More importantly, it can remain 3.31 F cm-2 (94.8% retention) after 5000 cycles. The as-obtained electrode also displays excellent rate capability, whose areal capacitance can still remain 2.79 F cm-2 while the discharge current density is increased to 50 mA cm-2. The remarkable electrochemical performance is mainly attributed to the unique heterogeneous core/sheath nanowire-array architectures.

  9. Amine-tethered solid adsorbents coupling high adsorption capacity and regenerability for CO2 capture from ambient air.

    Science.gov (United States)

    Choi, Sunho; Gray, McMahan L; Jones, Christopher W

    2011-05-23

    Silica supported poly(ethyleneimine) (PEI) materials are prepared via impregnation and demonstrated to be promising adsorbents for CO(2) capture from ultra-dilute gas streams such as ambient air. A prototypical class 1 adsorbent, containing 45 wt% PEI (PEI/silica), and two new modified PEI-based aminosilica adsorbents, derived from PEI modified with 3-aminopropyltrimethoxysilane (A-PEI/silica) or tetraethyl orthotitanate (T-PEI/silica), are prepared and characterized by using thermogravimetric analysis and FTIR spectroscopy. The modifiers are shown to enhance the thermal stability of the polymer-oxide composites, leading to higher PEI decomposition temperatures. The modified adsorbents present extremely high CO(2) adsorption capacities under conditions simulating ambient air (400 ppm CO(2) in inert gas), exceeding 2 mol(CO (2)) kg(sorbent)(-1), as well as enhanced adsorption kinetics compared to conventional class 1 sorbents. The new adsorbents show excellent stability in cyclic adsorption-desorption operations, even under dry conditions in which aminosilica adsorbents are known to lose capacity due to urea formation. Thus, the adsorbents of this type can be considered promising materials for the direct capture of CO(2) from ultra-dilute gas streams such as ambient air. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  11. High Resolution Measurement of Rhizosphere Priming Effects and Temporal Variability of CO2 Fluxes under Zea Mays

    Science.gov (United States)

    Splettstößer, T.; Pausch, J.

    2016-12-01

    Plant induced increase of soil organic matter turnover rates contribute to carbon emissions in agricultural land use systems. In order to better understand these rhizosphere priming effects, we conducted an experiment, which enabled us to monitor CO2 fluxes under zea mays plants with high resolution. The experiment was conducted in a climate chamber where the plants were grown in thin, tightly sealed boxes for 40 days and CO2 efflux from soil was measured twice a day. 13C-CO2 was introduced to allow differentiation between plant and soil derived CO2.This enabled us to monitor root respiration and soil organic matter turnover in the early stages of plant growth and to highlight changes in soil CO2 emissions and priming effects between day and night. The measurements were conducted with a PICARRO G2131-I δ13C high-precision isotopic CO2 Analyzer (PICARRO INC.) utilizing an automated valve system governed by a CR1000 data logger (Campbell Scientific). After harvest roots and shoots were analyzed for 13C content. Microbial biomass, root length density and enzymatic activities in soil were measured and linked to soil organic matter turnover rates. In order to visualize the spatial distribution of carbon allocation to the root system a few plants were additionally labeled with 14C and 14C distribution was monitored by 14C imaging of the root systems over 4 days. Based on the 14C distribution a grid was chosen and the soil was sampled from each square of the grid to investigate the impact of carbon allocation hotspots on enzymatic activities and microbial biomass. First initial results show an increase of soil CO2 efflux in the night periods, whereby the contribution of priming is not fully analyzed yet. Additionally, root tips were identified as hotspots of short term carbon allocation via 14C imaging and an in increase in microbial biomass could be measured in this regions. The full results will be shown at AGU 2016.

  12. A Semi-Analytical Method for Rapid Estimation of Near-Well Saturation, Temperature, Pressure and Stress in Non-Isothermal CO2 Injection

    Science.gov (United States)

    LaForce, T.; Ennis-King, J.; Paterson, L.

    2015-12-01

    Reservoir cooling near the wellbore is expected when fluids are injected into a reservoir or aquifer in CO2 storage, enhanced oil or gas recovery, enhanced geothermal systems, and water injection for disposal. Ignoring thermal effects near the well can lead to under-prediction of changes in reservoir pressure and stress due to competition between increased pressure and contraction of the rock in the cooled near-well region. In this work a previously developed semi-analytical model for immiscible, nonisothermal fluid injection is generalised to include partitioning of components between two phases. Advection-dominated radial flow is assumed so that the coupled two-phase flow and thermal conservation laws can be solved analytically. The temperature and saturation profiles are used to find the increase in reservoir pressure, tangential, and radial stress near the wellbore in a semi-analytical, forward-coupled model. Saturation, temperature, pressure, and stress profiles are found for parameters representative of several CO2 storage demonstration projects around the world. General results on maximum injection rates vs depth for common reservoir parameters are also presented. Prior to drilling an injection well there is often little information about the properties that will determine the injection rate that can be achieved without exceeding fracture pressure, yet injection rate and pressure are key parameters in well design and placement decisions. Analytical solutions to simplified models such as these can quickly provide order of magnitude estimates for flow and stress near the well based on a range of likely parameters.

  13. Investigation of Peculiarities of a High-Voltage Pulsing Corona Discharge in Carbonic Gas and an Feature Using of Such Discharge for CO2 Dissociation

    International Nuclear Information System (INIS)

    Berezina, G.P.; Mirny, V.I.; Omelaenko, O.L.; Us, V.S.

    2006-01-01

    On laboratory stand of plasmochemical reactor the feature of CO 2 dissociation with the purpose of CO production in high-voltage pulsing corona discharge is investigated at a voltage up to 120 kV, a pulse length of a current 0,5 μs a repetition rate up to 100 Hz. Peculiarities of volt-ampere characteristics of such discharge are studied at different pressures of air and carbonic gas in the discharge chamber and construction of an interior electrode. It is established that in conditions of the carried out experiments a maximum efficiency of CO accretion does not exceed 3,5%

  14. Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo2 and Er(Co1-xSix)2

    International Nuclear Information System (INIS)

    Singh, Niraj K; Kumar, Pramod; Suresh, K G; Nigam, A K; Coelho, A A; Gama, S

    2007-01-01

    The effect of external pressure on the magnetic properties and magnetocaloric effect of polycrystalline compounds DyCo 2 and Er(Co 1-x Si x ) 2 (x = 0,0.025 and 0.05) has been studied. The ordering temperatures of both the parent and the Si-substituted compounds are found to decrease with pressure. In all the compounds, the critical field for metamagnetic transition increases with pressure. It is seen that the magnetocaloric effect in the parent compounds is almost insensitive to pressure, while there is considerable enhancement in the case of Si-substituted compounds. Spin fluctuations arising from the magnetovolume effect play a crucial role in determining the pressure dependence of the magnetocaloric effect in these compounds. The variation of the magnetocaloric effect is explained on the basis of the Landau theory of magnetic phase transitions

  15. The penalty of a long, hot summer. Photosynthetic acclimation to high CO2 and continuous light in "living fossil" conifers.

    Science.gov (United States)

    Osborne, Colin P; Beerling, David J

    2003-10-01

    Deciduous forests covered the ice-free polar regions 280 to 40 million years ago under warm "greenhouse" climates and high atmospheric pCO2. Their deciduous habit is frequently interpreted as an adaptation for minimizing carbon losses during winter, but experiments with "living fossils" in a simulated warm polar environment refute this explanation. Measured carbon losses through leaf abscission of deciduous trees are significantly greater than losses through winter respiration in evergreens, yet annual rates of primary productivity are similar in all species. Here, we investigate mechanisms underlying this apparent paradox by measuring the seasonal patterns of leaf photosynthesis (A) under pCO2 enrichment in the same trees. During spring, A increased significantly in coastal redwood (Sequoia sempervirens), dawn redwood (Metasequoia glyptostroboides), and swamp cypress (Taxodium distichum) at an elevated pCO2 of 80 Pa compared with controls at 40 Pa. However, strong acclimation in Rubisco carboxylation capacity (Vc,max) completely offset the CO2 response of A in all species by the end of 6 weeks of continuous illumination in the simulated polar summer. Further measurements demonstrated the temporary nature of acclimation, with increases in Vc,max during autumn restoring the CO2 sensitivity of A. Contrary to expectations, the acclimation of Vc,max was not always accompanied by accumulation of leaf carbohydrates, but was associated with a decline in leaf nitrogen in summer, suggesting an alteration of the balance in plant sources and sinks for carbon and nitrogen. Preliminary calculations using A indicated that winter carbon losses through deciduous leaf abscission and respiration were recovered by 10 to 25 d of canopy carbon fixation during summer, thereby explaining the productivity paradox.

  16. Thermal damage produced by high-irradiance continuous wave CO2 laser cutting of tissue.

    Science.gov (United States)

    Schomacker, K T; Walsh, J T; Flotte, T J; Deutsch, T F

    1990-01-01

    Thermal damage produced by continuous wave (cw) CO2 laser ablation of tissue in vitro was measured for irradiances ranging from 360 W/cm2 to 740 kW/cm2 in order to investigate the extent to which ablative cooling can limit tissue damage. Damage zones thinner than 100 microns were readily produced using single pulses to cut guinea pig skin as well as bovine cornea, aorta, and myocardium. Multiple pulses can lead to increased damage. However, a systematic decrease in damage with irradiance, predicted theoretically by an evaporation model of ablation, was not observed. The damage-zone thickness was approximately constant around the periphery of the cut, consistent with the existence of a liquid layer which stores heat and leads to tissue damage, and with a model of damage and ablation recently proposed by Zweig et al.

  17. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2016-07-29

    According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO2 emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H2). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

  18. Measurements and trend analysis of O2, CO2 and δ13C of CO2 from the high altitude research station Junfgraujoch, Switzerland - A comparison with the observations from the remote site Puy de Dome, France

    International Nuclear Information System (INIS)

    Valentino, Francesco L.; Leuenberger, Markus; Uglietti, Chiara; Sturm, Patrick

    2008-01-01

    Atmospheric O 2 and CO 2 flask measurements from the high altitude research station Jungfraujoch, Switzerland, and from the observatory at Puy de Dome, France, are presented. Additionally, the Jungfraujoch δ 13 C record of CO 2 is discussed. The observations on flask samples collected at the Jungfraujoch station show, since 2003, an enhancement of the oxygen trend which amounts to about 45 per meg/year with a corresponding CO 2 increase of around 2.4 ppm/year. This enhancement is comparable with that observed at the Puy de Dome station where oxygen, since mid 2002, has decreased with a rate of about 50 per meg/year whilst the CO 2 increase was of around 1.7 ppm/year but exhibiting a higher variability. Several processes influence δO 2 /N 2 . However, these processes are marked with different oxidation ratios (O 2 :CO 2 ) that can be used to distinguish them. The apparent slopes calculated from correlation plots between de-trended CO 2 and δO 2 /N 2 records as well as between corresponding trends are significantly larger than the observed terrestrial exchange and fossil fuel emission slopes indicating a strong oceanic influence. Since ocean-atmosphere exchange can have very variable O 2 :CO 2 ratios depending on processes within the ocean, it is to our understanding the only possibility to explain our observations. The stability of the δO 2 /N 2 scale is critical in this regard, therefore, it is addressed here and we found no significant scale drift which would influence our trend calculations. In our view more important are criterions on the data selection before trend analysis

  19. Fascination at high pressures

    International Nuclear Information System (INIS)

    Chidambaram, R.

    1992-01-01

    Research at high pressures has developed into an interdisciplinary area which has important implications for and applications in the areas of physics, chemistry, materials sciences, planetary sciences, biology, engineering sciences and technology. The state of-the-art in this field is reviewed and future directions are indicated. (M.G.B.)

  20. Inactivation of microorganisms for high pressures in the wine industry

    International Nuclear Information System (INIS)

    Montana B, Jaime Nelson; Ortegon T, Sandra Patricia

    2000-01-01

    In order to evaluate experimentally the capacity of N 2 and CO 2 under pressure to inactivate wild yeasts, which remain in the Puntalarga vineyard grape, musts were exposed to hyperbaric treatment with these gases. At the end of the pascalization (after 2 hours), CO 2 at 15 degrades Celsius under pressures from 1 to 5 MPa, reached high inactivation percentages of yeast cells (> 90%). Contrary to CO 2 treatment the use of N 2 at 15 degrades Celsius at 4 and 10 MPa failed to exert microbicide effect in a same treatment time. While CO 2 gas with high solubility in water has the potential to reduce microbial loads in musts, N 2 gas with low solubility in water have not effect on the survival of the pathogenic microorganisms in these juices

  1. Coupled Hydro-Mechanical Simulations of CO2 Storage Supported by Pressure Management Demonstrate Synergy Benefits from Simultaneous Formation Fluid Extraction

    Directory of Open Access Journals (Sweden)

    Kempka Thomas

    2015-04-01

    Full Text Available We assessed the synergetic benefits of simultaneous formation fluid extraction during CO2 injection for reservoir pressure management by coupled hydro-mechanical simulations at the prospective Vedsted storage site located in northern Denmark. Effectiveness of reservoir pressure management was investigated by simulation of CO2 storage without any fluid extraction as well as with 66% and 100% equivalent volume formation fluid extraction from four wells positioned for geothermal heat recovery. Simulation results demonstrate that a total pressure reduction of up to about 1.1 MPa can be achieved at the injection well. Furthermore, the areal pressure perturbation in the storage reservoir can be significantly decreased compared to the simulation scenario without any formation fluid extraction. Following a stress regime analysis, two stress regimes were considered in the coupled hydro-mechanical simulations indicating that the maximum ground surface uplift is about 0.24 m in the absence of any reservoir pressure management. However, a ground uplift mitigation of up to 37.3% (from 0.24 m to 0.15 m can be achieved at the injection well by 100% equivalent volume formation fluid extraction. Well-based adaptation of fluid extraction rates can support achieving zero displacements at the proposed formation fluid extraction wells located close to urban infrastructure. Since shear and tensile failure do not occur under both stress regimes for all investigated scenarios, it is concluded that a safe operation of CO2 injection with simultaneous formation fluid extraction for geothermal heat recovery can be implemented at the Vedsted site.

  2. Effects of pressure and magnetic field on transport properties of Y1-xRxCo2 alloys (R=Gd, Tb, Dy, Ho and Er)

    International Nuclear Information System (INIS)

    Takaesu, Y; Nakama, T; Kinjyo, A; Yonamine, S; Hedo, M; Yagasaki, K; Uchima, K; Uwatoko, Y; Burkov, A T

    2010-01-01

    Electrical resistivity ρ and thermopower S of Y 1-x R x Co 2 (R=Gd, Tb, Dy, Ho and Er) Laves phase alloy systems were measured at temperatures from 1.5 K to 300 K in magnetic fields up to 15 T and under hydrostatic pressure up to 2 GPa. We show that there is a universal linear relation between the pressure and magnetic field derivatives of the resistivity, dρ/dP and dρ/dB, with gradient, determined by pressure derivative of the critical metamagnetic field of the cobalt 3d electron system. A similar scaling behavior was found for the thermopower dependencies on pressure and alloy composition.

  3. Responses of CO2 Fluxes to Arctic Browning Events in a Range of High Latitude, Shrub-Dominated Ecosystems

    Science.gov (United States)

    Phoenix, G. K.; Treharne, R.; Emberson, L.; Tømmervik, H. A.; Bjerke, J. W.

    2017-12-01

    Climatic and biotic extreme events can result in considerable damage to arctic vegetation, often at landscape and larger scale. These acute events therefore contribute to the browning observed in some arctic regions. It is of considerable concern, therefore, that such extreme events are increasing in frequency as part of climate change. However, despite the increasing importance of browning events, and the considerable impact they can have on ecosystems, to date there is little understanding of their impacts on ecosystem carbon fluxes. To address this, the impacts of a number of different, commonly occurring, extreme events and their subsequent browning (vegetation damage) on key ecosystem CO2 fluxes were assessed during the growing season at a range of event damaged sites of shrub dominated vegetation. Sites were located from the boreal to High Arctic (64˚N-79˚N) and had been previously been damaged by events of frost-drought, extreme winter warming, ground icing and caterpillar (Epirrita autumnata) outbreaks. Plot-level CO2 fluxes of Ecosystem Exchange (NEE), Gross Primary Productivity (GPP) and Ecosystem Respiration (Reco) were assessed using vegetation chambers. At a sub-set of sites, NDVI (greenness) in flux plots was also assessed by hand-held proximal sensor, allowing the relationship between NDVI of damage plots to CO2 flux to be calculated. Despite the contrasting sites and drivers, damage had consistent, major impacts on all fluxes. All sites showed reductions in GPP and NEE with increasing damage, despite efflux from Reco also declining with damage. When scaled to site-level, reductions of up to 81% of NEE, 51% of GPP and 37% of Reco were observed. In the plot-level NDVI-flux relationship, NDVI was shown to explain up to 91% of variation in GPP, and therefore supports the use of NDVI for estimating changes in ecosystem CO2 flux at larger scales in regions where browning has been driven by extreme events. This work is the first attempt to quantify the

  4. Comparison of atmospheric CO2 columns at high latitudes from ground-based and satellite-based methods

    Science.gov (United States)

    Jacobs, N.; Simpson, W. R.; Parker, H. A.; Tu, Q.; Blumenstock, T.; Dubey, M. K.; Hase, F.; Osterman, G. B.

    2017-12-01

    Total column measurements of carbon-dioxide (CO2) from the Orbiting Carbon Observatory-2 (OCO-2) satellite have been validated at mid-latitudes by comparison to the Total Carbon Column Observing Network (TCCON), but there are still a limited number of sites providing high-latitude validation data for satellite observations of CO2, and no TCCON sites in Alaska. To understand the global distribution of CO2 sources and sinks, it is essential that we increase the abundance of validation sites, particularly in the climate-sensitive high-latitude Boreal forest. Therefore, we began the Arctic Mobile Infrared Greenhouse Gas Observations (AMIGGO) campaign in the Boreal Forest region around Fairbanks, Alaska with the goal of satellite validation and measurement of natural ecosystem fluxes. In this campaign, we used the EM27/SUN mobile solar-viewing Fourier-transform infrared spectrometer (EM27/SUN FTS) to retrieve the total CO2 column and column-averaged dry-air mole fraction of CO2 (XCO2) with the GGG2014 algorithm. The EM27/SUN FTS was developed by the Karlsruhe Institute of Technology (KIT) in collaboration with Bruker optics (Gisi et al., 2012, doi:10.5194/amt-5-2969-2012) and has been deployed in urban areas to measure anthropogenic fluxes of CO2 and CH4. To evaluate the EM27/SUN performance, co-located observations were made with two EM27/SUN spectrometers, and we found that XCO2 differences between spectrometers were small (0.24ppm on average) and very stable over time. In this presentation, we report on 14 OCO-2 targeted overpasses that occurred from August 2016 through July 2017, along with additional targets obtained during ongoing observations in 2017. We investigate underlying reasons for observed differences between OCO-2 and ground-based XCO2 using methods developed by Wunch et al. (2017, doi:10.5194/amt-10-2209-2017). As an additional point of comparison, coincident aircraft observations by NOAA Earth System Research Laboratory (ESRL) Global Monitoring

  5. Thermophysical and radiation properties of high-temperature C4F8-CO2 mixtures to replace SF6 in high-voltage circuit breakers

    Science.gov (United States)

    Zhong, Linlin; Cressault, Yann; Teulet, Philippe

    2018-03-01

    C4F8-CO2 mixtures are one of the potential substitutes to SF6 in high-voltage circuit breakers. However, the arc quenching ability of C4F8-CO2 mixtures is still unknown. In order to provide the necessary basic data for the further investigation of arc quenching performance, the compositions, thermodynamic properties, transport coefficients, and net emission coefficients (NEC) of various C4F8-CO2 mixtures are calculated at temperatures of 300-30 000 K in this work. The thermodynamic properties are presented as the product of mass density and specific heat, i.e., ρCp. The transport coefficients include electrical conductivity, viscosity, and thermal conductivity. The atomic and molecular radiation are both taken into account in the calculation of NEC. The comparison of the properties between SF6 and C4F8-CO2 mixtures is also discussed to find their differences. The results of compositions show that C4F8-CO2 mixtures have a distinctive advantage over other alternative gases e.g., CF3I and C3F8, because the dissociative product (i.e., C4F6) of C4F8 at low temperatures has a very high dielectric strength. This is good for an arc quenching medium to endure the arc recovery phase. Compared with SF6, C4F8-CO2 mixtures present lower ρCp at temperatures below 2800 K and larger thermal conductivity above 2800 K. Based on the position of peaks in thermal conductivity, we predict that the cooling of C4F8-CO2 arc will be slowed down at higher temperatures than that of SF6 arc. It is also found that the mixing of CO2 shows slight effects on the electrical conductivity and NEC of C4F8-CO2 mixtures.

  6. Multicollector High Precision Resolution of Primordial Kr and Xe in Mantle CO2 Well Gases

    Science.gov (United States)

    Holland, G.; Ballentine, C.; Cassidy, M.

    2008-12-01

    Noble gas isotopes in magmatic CO2 well gases provide a unique insight into mantle volatile origin and dynamics [1-3]. Previous work has resolved mantle 20Ne/22Ne ratios consistent with a solar wind irradiated meteoritic source for mantle He and Ne [1]. This is distinct from Solar Wind values that might be expected if the primary mechanism of terrestrial mantle volatile acquisition was through the gravitational capture of solar nebula gases [see 4]. Within the CO2 well gases a primordial component has also been resolved in the non- radiogenic Xe isotopic composition [2,3]. Using multicollector mass spectrometry we have observed a 124Xe/130Xe excess of 1.85 percent over air plus/minus 0.17 percent for the least air contaminated samples. At this level of precision we are for the first time able to differentiate between a trapped meteoritic origin (average carbonaceous chondrite or Q Xe) rather than Solar Wind origin as the primordial Xe component. The well gases also contain Kr which, in the least air contaminated sample, have a correlated 86Kr/82Kr excess of 0.55 percent over air plus/minus 0.04 percent. Whilst mass dependent fractionation can theoretically produce correlated excesses in 124Xe-128Xe and 82Kr-86Kr isotopes, no fractionation from air is observed in 38Ar/36Ar [3] and the Kr excesses are in the opposite sense to that of Xe. From 136Xe excesses, Kr fission yield from Pu and U can be calculated and subtracted from the Kr isotopic signature. This fission-corrected signature is most reasonably explained as a primordial component. This is the first time that primordial Kr has ever been resolved in a terrestrial sample. The primordial Kr isotopic signature is distinct from Solar Wind Kr and is consistent with the primordial Kr also originating as a trapped component within meteorites. We are now able to demonstrate that both the light (He and Ne) and Heavy (Kr and Xe) noble gas origin in the terrestrial mantle is consistent with a trapped component during the

  7. Solubility and diffusivity of CO2 in the ionic liquid 1-butyl-3-methylimidazolium tricyanomethanide within a large pressure range (0.01 MPa to 10 MPa)

    NARCIS (Netherlands)

    Zubeir, L.F.; Romanos, G.E.; Weggemans, W.M.A.; Iliev, B.; Schubert, T.J.S.; Kroon, M.C.

    2015-01-01

    Ionic liquids (ILs) are promising solvents for carbon capture because of their high sorption capacity and low regeneration energy compared to conventional amine-based solvents. Previously, tetracyanoborate-based ILs have shown enhanced carbon dioxide (CO2) absorption capacity and absorption kinetics

  8. Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

    International Nuclear Information System (INIS)

    Chiper, A S; Chen, W; Stamate, E; Mejlholm, O; Dalgaard, P

    2011-01-01

    The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO 2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A-X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three times higher in the Ar/CO 2 plasma compared with an Ar plasma. The efficiency of the produced plasma for the inactivation of bacteria on food inside the closed package was investigated.

  9. Growth of highly mesoporous CuCo2O4@C core-shell arrays as advanced electrodes for high-performance supercapacitors

    Science.gov (United States)

    Yan, Hailong; Lu, Yang; Zhu, Kejia; Peng, Tao; Liu, Xianming; Liu, Yunxin; Luo, Yongsong

    2018-05-01

    A series of CuCo2O4 nanostructures with different morphologies were prepared by a hydrothermal method in combination with thermal treatment. The morphology, structure and composition were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. As the electrode materials for supercapacitors, CuCo2O4 nanoneedles delivered the highest specific capacitance compared with other CuCo2O4 nanostructures. Electrochemical performance measurements demonstrate that the carbon layer can improve the electrochemical stability of CuCo2O4 nanoneedles. The CuCo2O4@C electrode exhibits a high specific capacitance of 1432.4 F g-1 at a current density of 1 A g-1, with capacitance retention of 98.2% after 3000 circles. These characteristics of CuCo2O4@C composite are mainly due to the unique one dimensional needle-liked architecture and the conducting carbon, which provide a faster ion/electron transfer rate. These excellent performances of the CuCo2O4@C electrode confirmed the material as a positive electrode for hybrid supercapacitor application.

  10. Effect of Leaf Water Potential on Internal Humidity and CO2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure.

    Science.gov (United States)

    Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; Salmon, Yann; Nikinmaa, Eero; Hari, Pertti; Hölttä, Teemu

    2017-01-01

    The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2 , thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. The omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange

  11. Bringing High-Rate, CO2-Based Microbial Electrosynthesis Closer to Practical Implementation through Improved Electrode Design and Operating Conditions.

    Science.gov (United States)

    Jourdin, Ludovic; Freguia, Stefano; Flexer, Victoria; Keller, Jurg

    2016-02-16

    The enhancement of microbial electrosynthesis (MES) of acetate from CO2 to performance levels that could potentially support practical implementations of the technology must go through the optimization of key design and operating conditions. We report that higher proton availability drastically increases the acetate production rate, with pH 5.2 found to be optimal, which will likely suppress methanogenic activity without inhibitor addition. Applied cathode potential as low as -1.1 V versus SHE still achieved 99% of electron recovery in the form of acetate at a current density of around -200 A m(-2). These current densities are leading to an exceptional acetate production rate of up to 1330 g m(-2) day(-1) at pH 6.7. Using highly open macroporous reticulated vitreous carbon electrodes with macropore sizes of about 0.6 mm in diameter was found to be optimal for achieving a good balance between total surface area available for biofilm formation and effective mass transfer between the bulk liquid and the electrode and biofilm surface. Furthermore, we also successfully demonstrated the use of a synthetic biogas mixture as carbon dioxide source, yielding similarly high MES performance as pure CO2. This would allow this process to be used effectively for both biogas quality improvement and conversion of the available CO2 to acetate.

  12. SC-CO2-assisted process for a high energy density aerogel supercapacitor: the effect of GO loading

    Science.gov (United States)

    Sarno, Maria; Baldino, Lucia; Scudieri, Carmela; Cardea, Stefano; Ciambelli, Paolo; Reverchon, Ernesto

    2017-05-01

    Energy density, safety, and simple and environmentally friendly preparation methods are very significant aspects in the realization of a compact supercapacitor. Herein we report the use of a supercritical CO2-assisted gel drying process (SC-CO2) for the preparation of porous electrodes containing dispersed graphene in a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) binder membrane to sandwich in a new portable supercapacitor based on graphene oxide (GO). A GO loading of 60 wt.% was found to give the best combination of factors (porosity, wettability, mechanical and electrochemical properties). Cycling voltammetry and charge/discharge studies showed an excellent capacitance behaviour and stability in an ionic liquid electrolyte, suggesting SC-CO2 processing as a promising platform to produce highly bulky and porous films for supercapacitors. The supercapacitor device delivers a very high energy density of 79.2 Wh kg-1 at a power density of 0.23 KW kg-1 (current density 0.5 A g-1, specific capacitance 36.2 F g-1) while that of steel remains at 50.3 Wh kg-1 at a power density of 2.8 KW kg-1 (current density 6 A g-1, specific capacitance 23.5 F g-1).

  13. A Nitrogen-Doped Carbon Catalyst for Electrochemical CO2 Conversion to CO with High Selectivity and Current Density.

    Science.gov (United States)

    Jhong, Huei-Ru Molly; Tornow, Claire E; Smid, Bretislav; Gewirth, Andrew A; Lyth, Stephen M; Kenis, Paul J A

    2017-03-22

    We report characterization of a non-precious metal-free catalyst for the electrochemical reduction of CO 2 to CO; namely, a pyrolyzed carbon nitride and multiwall carbon nanotube composite. This catalyst exhibits a high selectivity for production of CO over H 2 (approximately 98 % CO and 2 % H 2 ), as well as high activity in an electrochemical flow cell. The CO partial current density at intermediate cathode potentials (V=-1.46 V vs. Ag/AgCl) is up to 3.5× higher than state-of-the-art Ag nanoparticle-based catalysts, and the maximum current density is 90 mA cm -2 . The mass activity and energy efficiency (up to 48 %) were also higher than the Ag nanoparticle reference. Moving away from precious metal catalysts without sacrificing activity or selectivity may significantly enhance the prospects of electrochemical CO 2 reduction as an approach to reduce atmospheric CO 2 emissions or as a method for load-leveling in relation to the use of intermittent renewable energy sources. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Double-Layer Structured CO2 Adsorbent Functionalized with Modified Polyethyleneimine for High Physical and Chemical Stability.

    Science.gov (United States)

    Jeon, Sunbin; Jung, Hyunchul; Kim, Sung Hyun; Lee, Ki Bong

    2018-06-18

    CO 2 capture using polyethyleneimine (PEI)-impregnated silica adsorbents has been receiving a lot of attention. However, the absence of physical stability (evaporation and leaching of amine) and chemical stability (urea formation) of the PEI-impregnated silica adsorbent has been generally established. Therefore, in this study, a double-layer impregnated structure, developed using modified PEI, is newly proposed to enhance the physical and chemical stabilities of the adsorbent. Epoxy-modified PEI and diepoxide-cross-linked PEI were impregnated via a dry impregnation method in the first and second layers, respectively. The physical stability of the double-layer structured adsorbent was noticeably enhanced when compared to the conventional adsorbents with a single layer. In addition to the enhanced physical stability, the result of simulated temperature swing adsorption cycles revealed that the double-layer structured adsorbent presented a high potential working capacity (3.5 mmol/g) and less urea formation under CO 2 -rich regeneration conditions. The enhanced physical and chemical stabilities as well as the high CO 2 working capacity of the double-layer structured adsorbent were mainly attributed to the second layer consisting of diepoxide-cross-linked PEI.

  15. Tropical coral reef habitat in a geoengineered, high-CO2 world

    Science.gov (United States)

    Couce, E.; Irvine, P. J.; Gregorie, L. J.; Ridgwell, A.; Hendy, E. J.

    2013-05-01

    Continued anthropogenic CO2 emissions are expected to impact tropical coral reefs by further raising sea surface temperatures (SST) and intensifying ocean acidification (OA). Although geoengineering by means of solar radiation management (SRM) may mitigate temperature increases, OA will persist, raising important questions regarding the impact of different stressor combinations. We apply statistical Bioclimatic Envelope Models to project changes in shallow water tropical coral reef habitat as a single niche (without resolving biodiversity or community composition) under various representative concentration pathway and SRM scenarios, until 2070. We predict substantial reductions in habitat suitability centered on the Indo-Pacific Warm Pool under net anthropogenic radiative forcing of ≥3.0 W/m2. The near-term dominant risk to coral reefs is increasing SSTs; below 3 W/m2 reasonably favorable conditions are maintained, even when achieved by SRM with persisting OA. "Optimal" mitigation occurs at 1.5 W/m2 because tropical SSTs overcool in a fully geoengineered (i.e., preindustrial global mean temperature) world.

  16. COMPARISON OF GINGER (Zingiber officiale Roscoe OLEORESIN OBTAINED WITH ETHANOL AND ISOPROPANOL WITH THAT OBTAINED WITH PRESSURIZED CO2

    Directory of Open Access Journals (Sweden)

    Lia P. NOBREGA

    1997-12-01

    Full Text Available Ginger (Zingiber officinale Roscoe belongs to the Zingiberacea family. It is a spice of great commercial importance. In this work ginger oleoresin was obtained with ethanol, isopropanol and liquid carbon dioxide. The chemical compositions of the extract were compared with each other. All oleoresin samples had monoterpenes and sesquiterpenes. Carboxylic acids were found in organic solvent extracts for an extraction time of 2 hours. The component responsible the for pungent characteristic of the oleoresin, gingerois, were detected in samples obtained with organic solvent for extraction times of 6 hours and in samples obtained with CO2 liquid for extraction times of 2 hours.O gengibre (Zingiber officinale Roscoe pertence à família Zingiberacea. É uma especiaria de grande importância comercial. Neste trabalho realizou-se extrações da oleoresina de gengibre com etanol, isopropanol e dióxido de carbono líquido e comparou-se a composição química de cada um dos extratos. A oleoresina obtida tem componentes das classes dos monoterpenos e sesquiterpenos em todas as amostras. Ácidos carboxílicos foram encontrados nos extratos obtidos com solvente orgânico, quando o tempo de extração foi de 2 horas. Os componentes que dão a característica pungente à oleoresina, os gingerois, foram detectados nas amostras obtidas com solvente orgânico, quando o tempo de extração foi de 6 horas e, nas amostras obtidas com CO2 líquido, com 2 horas de extração.

  17. High-permeance crosslinked PTMSP thin-film composite membranes as supports for CO2 selective layer formation

    Directory of Open Access Journals (Sweden)

    Stepan D. Bazhenov

    2016-10-01

    Full Text Available In the development of the composite gas separation membranes for post-combustion CO2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology. The primary requirements to the membrane supports are concerned with their high CO2 permeance. In this work, the membrane supports with desired characteristics were developed as high-permeance gas separation thin film composite (TFC membranes with the thin defect-free layer from the crosslinked highly permeable polymer, poly[1-(trimethylsilyl-1-propyne] (PTMSP. This layer is insoluble in chloroform and can be used as a gutter layer for the further deposition of the СО2-selective materials from the organic solvents. Crosslinking of PTMSP was performed using polyethyleneimine (PEI and poly (ethyleneglycol diglycidyl ether (PEGDGE as crosslinking agents. Optimal concentrations of PEI in PTMSP and PEGDGE in methanol were selected in order to diminish the undesirable effect on the final membrane gas transport characteristics. The conditions of the kiss-coating technique for the deposition of the thin defect-free PTMSP-based layer, namely, composition of the casting solution and the speed of movement of the porous commercial microfiltration-grade support, were optimized. The procedure of post-treatment with alcohols and alcohol solutions was shown to be crucial for the improvement of gas permeance of the membranes with the crosslinked PTMSP layer having thickness ranging within 1–2.5 μm. The claimed membranes showed the following characteristics: CO2 permeance is equal to 50–54 m3(STP/(m2 h bar (18,500–20,000 GPU, ideal CO2/N2 selectivity is 3.6–3.7, and their selective layers are insoluble in chloroform. Thus, the developed high-permeance TFC membranes are considered as a promising supports for further modification by enhanced CO2 selective layer formation. Keywords: Thin-film composite membrane

  18. The CO_2 absorption spectrum in the 2.3 µm transparency window by high sensitivity CRDS: (I) Rovibrational lines

    International Nuclear Information System (INIS)

    Vasilchenko, S.; Konefal, M.; Mondelain, D.; Kassi, S.; Čermák, P.; Tashkun, S.A.; Perevalov, V.I.; Campargue, A.

    2016-01-01

    The absorption of carbon dioxide is very weak near 2.3 µm which makes this transparency window of particular interest for the study of Venus’ lower atmosphere. As a consequence of the weakness of the transitions located in this region, previous experimental data are very scarce and spectroscopic databases provide calculated line lists which should be tested and validated by experiment. In this work, we use the Cavity Ring Down Spectroscopy (CRDS) technique for a high sensitivity characterization of the CO_2 absorption spectrum in two spectral intervals of the 2.3 µm window: 4248–4257 and 4295–4380 cm"−"1 which were accessed using a Distributed Feed Back (DFB) diode laser and a Vertical External Cavity Surface Emitting Laser (VECSEL) as light sources, respectively. The achieved sensitivity (noise equivalent absorption, α_m_i_n, on the order of 5×10"−"1"0 cm"−"1) allowed detecting numerous new transitions with intensity values down to 5×10"−"3"0 cm/molecule. The rovibrational assignments were performed by comparison with available theoretical line lists in particular those obtained at IAO Tomsk using the global effective operator approach. Hot bands of the main isotopologue and "1"6O"1"2C"1"8O bands were found to be missing in the HITRAN database while they contribute importantly to the absorption in the region. Additional CRDS spectra of a CO_2 sample highly enriched in "1"8O were recorded in order to improve the spectroscopy of this isotopologue. As a result about 700 lines of "1"6O"1"2C"1"8O, "1"6O"1"2C"1"7O, "1"7O"1"2C"1"8O, "1"2C"1"8O_2 and "1"3C"1"8O_2 were newly measured. The status of the different databases (HITRAN, CDSD, variational calculations) in the important 2.3 µm transparency window is discussed. Possible improvements to correct evidenced deficiencies are suggested. - Highlights: • High sensitivity CRDS with a VECSEL in the 2.3 µm transparency window of CO_2. • Natural and "1"8O enriched CO_2 spectra recorded with

  19. Measurement and modeling of CO2 solubility in NaCl brine and CO2–saturated NaCl brine density

    DEFF Research Database (Denmark)

    Yan, Wei; Huang, Shengli; Stenby, Erling Halfdan

    2011-01-01

    over climate change and energy security. This work is an experimental and modeling study of two fundamental properties in high pressure CO2–NaCl brine equilibrium, i.e., CO2 solubility in NaCl brine and CO2–saturated NaCl brine density. A literature review of the available data was presented first...

  20. Stem juice production of the C4 sugarcane (Saccharum officinarum) is enhanced by growth at double-ambient CO2 and high temperature.

    Science.gov (United States)

    Vu, Joseph C V; Allen, Leon H

    2009-07-15

    Two cultivars of sugarcane (Saccharum officinarum cv. CP73-1547 and CP88-1508) were grown for 3 months in paired-companion, temperature-gradient, sunlit greenhouses under daytime [CO2] of 360 (ambient) and 720 (double ambient) micromol mol(-1) and at temperatures of 1.5 degrees C (near ambient) and 6.0 degrees C higher than outside ambient temperature. Leaf area and biomass, stem biomass and juice and CO2 exchange rate (CER) and activities of ribulose bisphosphate carboxylase-oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC) of fully developed leaves were measured at harvest. On a main stem basis, leaf area, leaf dry weight, stem dry weight and stem juice volume were increased by growth at doubled [CO2] or high temperature. Such increases were even greater under combination of doubled [CO2]/high temperature. Plants grown at doubled [CO2]/high temperature combination averaged 50%, 26%, 84% and 124% greater in leaf area, leaf dry weight, stem dry weight and stem juice volume, respectively, compared with plants grown at ambient [CO2]/near-ambient temperature combination. In addition, plants grown at doubled [CO2]/high temperature combination were 2-3-fold higher in stem soluble solids than those at ambient [CO2]/near-ambient temperature combination. Although midday CER of fully developed leaves was not affected by doubled [CO2] or high temperature, plants grown at doubled [CO2] were 41-43% less in leaf stomatal conductance and 69-79% greater in leaf water-use efficiency, compared with plants grown at ambient [CO2]. Activity of PEPC was down-regulated 23-32% at doubled [CO2], while high temperature did not have a significant impact on this enzyme. Activity of Rubisco was not affected by growth at doubled [CO2], but was reduced 15-28% at high temperature. The increases in stem juice production and stem juice soluble solids concentration for sugarcane grown at doubled [CO2] or high temperature, or at doubled [CO2]/high temperature combination, were partially

  1. Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent.

    Science.gov (United States)

    Apostolaki, Eugenia T; Vizzini, Salvatrice; Hendriks, Iris E; Olsen, Ylva S

    2014-08-01

    We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and δ(13)C of leaves and epiphytes were significantly lower at the low pH station. Photosynthetic activity of C. nodosa was stimulated by low pH as seen by the significant increase in Chla content of leaves, maximum electron transport rate and compensation irradiance. Seagrass community metabolism was intense at the low pH station, with significantly higher net community production, respiration and gross primary production than the control community, whereas metabolism of the unvegetated community did not differ between stations. Productivity was promoted by the low pH, but this was not translated into biomass, probably due to nutrient limitation, grazing or poor environmental conditions. The results indicate that seagrass response in naturally acidified conditions is dependable upon species and geochemical characteristics of the site and highlight the need for a better understanding of complex interactions in these environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Tropical Cyclones Cause CaCO3 Undersaturation of Coral Reef Seawater in a High-CO2 World

    Science.gov (United States)

    Manzello, D.; Enochs, I.; Carlton, R.; Musielewicz, S.; Gledhill, D. K.

    2013-12-01

    Ocean acidification is the global decline in seawater pH and calcium carbonate (CaCO3) saturation state (Ω) due to the uptake of anthropogenic CO2 by the world's oceans. Acidification impairs CaCO3 shell and skeleton construction by marine organisms. Coral reefs are particularly vulnerable, as they are constructed by the CaCO3 skeletons of corals and other calcifiers. We understand relatively little about how coral reefs will respond to ocean acidification in combination with other disturbances, such as tropical cyclones. Seawater carbonate chemistry data collected from two reefs in the Florida Keys before, during, and after Tropical Storm Isaac provide the most thorough data to-date on how tropical cyclones affect the seawater CO2-system of coral reefs. Tropical Storm Isaac caused both an immediate and prolonged decline in seawater pH. Aragonite saturation state was depressed by 1.0 for a full week after the storm impact. Based on current 'business-as-usual' CO2 emissions scenarios, we show that tropical cyclones with high rainfall and runoff can cause periods of undersaturation (Ω negatively impact the structural persistence of coral reefs over this century.

  3. Hydrothermal synthesis of NiCo2O4 nanowires/nitrogen-doped graphene for high-performance supercapacitor

    International Nuclear Information System (INIS)

    Yu, Mei; Chen, Jianpeng; Ma, Yuxiao; Zhang, Jingdan; Liu, Jianhua; Li, Songmei; An, Junwei

    2014-01-01

    Highlights: • NCO/NG composites were synthesized in a water–glycerol mixed solvent via hydrothermal treatment and subsequent calcination. • NiCo 2 O 4 nanowires are dispersed on NG nanosheets and the composite has porous structure. • The NCO/NG composite exhibits a high specific capacitance and long cycling performance. - Abstract: NiCo 2 O 4 nanowires/nitrogen-doped graphene (NCO/NG) composite materials were synthesized by hydrothermal treatment in a water–glycerol mixed solvent and subsequent thermal transformation. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The electrochemical performance of the composites was evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrum techniques. NiCo 2 O 4 nanowires are densely coated by nitrogen-doped graphene and the composite displays good electrochemical performance. The maximum specific capacitance of NCO/NG is 1273.13 F g −1 at 0.5 A g −1 in 6 M KOH aqueous solution, and it exhibits good capacity retention without noticeable degradation after 3000 cycles at 4 A g −1

  4. Predicting Effects of Corrosion Erosion of High Strength Steel Pipelines Elbow on CO2-Acetic Acid (HAc) Solution

    International Nuclear Information System (INIS)

    Asmara, Y. P.; Ismail, M. F.; Chui, L. Giok; Halimi, Jamiludin

    2016-01-01

    Simultaneously effect of erosion combined with corrosion becomes the most concern in oil and gas industries. It is due to the fast deterioration of metal as effects of solid particles mixed with corrosive environment. There are many corrosion software to investigate possible degradation mechanisms developed by researchers. They are using many combination factors of chemical reactions and physical process. However effects of CO 2 and acid on pipelines orientations are still remain uncovered in their simulation. This research will investigate combination effects of CO 2 and HAc on corrosion and erosion artificial environmental containing sands particles in 45°, 90° and 180° elbow pipelines. The research used theoretical calculations combined with experiments for verification. The main concerns are to investigate the maximum erosion corrosion rate and maximum shear stress at the surface. Methodology used to calculate corrosion rate are Linear Polarization Resistance (LPR) and weight loss. The results showed that at 45°, erosion rate is the more significant effects in contributing degradation of the metal. The effects of CO 2 and HAc gave significant effects when flow rate of the solution are high which reflect synergism effects of solid particles and those chemical compositions. (paper)

  5. Photosynthetic pigments and gas exchange in castor bean under conditions of above the optimal temperature and high CO2

    Directory of Open Access Journals (Sweden)

    Fabiola França Silva

    2015-08-01

    Full Text Available The castor bean plant, a Euphorbiaceae oil seed C3-metabolism rustic and drought-resistant plant, is cultivated in a wide range of environments due to its good adaptive capacity. However, given the current environmental changes, many biochemical and physiological impacts may affect the productivity of important crops, such as castor bean. This work aimed to evaluate the impacts of the castor bean gas exchange in response to high temperature and increased CO2concentration.Our experiment was conducted in a phytotron located at Embrapa Algodão in 2010. We adopted a completely randomized design, with four treatments in a factorial combination of two temperatures (30/20 and 37/30°C and two CO2 levels (400 and 800 mmol L-1; four replications were performed, obtained in five surveys over the growth cycle, for a total of 80 sample units. An infrared gas analyzer (IRGA - Infra Red Gas Analyzer was used for the quantification of the photosynthetic rate, stomatal conductance and transpiration. An increase in the atmospheric CO2 concentration and temperature negatively affected the physiology of the castor bean plants, decreasing the net rate of photosynthesis, transpiration and stomatal conductance.

  6. Supercritical CO2 foaming of radiation crosslinked polypropylene/high-density polyethylene blend: Cell structure and tensile property

    Science.gov (United States)

    Yang, Chenguang; Xing, Zhe; Zhang, Mingxing; Zhao, Quan; Wang, Mouhua; Wu, Guozhong

    2017-12-01

    A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO2) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8-12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO2 foaming of crosslinked PP with the addition of HDPE.

  7. Growth CO2 concentration modifies the transpiration response of Populus deltoides to drought and vapor pressure deficit

    International Nuclear Information System (INIS)

    Engel, V. C.; Griffin, K. L.; Murthy, R.; Patterson, L.; Klimas, C.; Potosnak, M.

    2004-01-01

    To gain a better understanding of the hydraulic constraints on transpiration, altered canopy water relations in response to elevated carbon dioxide was evaluated in a morphological context. It was expected that by integrating the information gained into predictive models of canopy water balance in elevated carbon dioxide, our understanding of leaf-level responses to drought stresses and evaporative demand will also improve. To achieve these objectives, transpiration rates and leaf-to-sapwood area ratios in clonal stands of cottonwoods grown in near-ambient and elevated carbon dioxide were measured at the Biosphere 2 facility near Oracle, Arizona. Results were interpreted in terms of physical controls versus the direct and indirect effects of growth mediated by morphological changes on transpiration fluxes during periods of drought and high evaporative demand. Leaf-level transpiration rates were found to be nearly equivalent across carbon dioxide treatments when soil water was not limited. However, during drought stress, canopy-level transpiration was roughly equivalent across carbon dioxide treatments, but leaf-level fluxes were reduced in elevated carbon dioxide by a factor equal to the leaf area ratio of the canopies. This shift from equivalent leaf-level transpiration to equivalent canopy-level transpiration with increasing drought stress is taken to mean that maximum water use rates are controlled by atmospheric demand at high soil water content and by soil water availability at low soil water content. Changes in vapor pressure deficits had less pronounced effect on transpiration than changes in soil water content. 37 refs., 3 tabs., 5 figs

  8. A sublimation technique for high-precision measurements of δ13CO2 and mixing ratios of CO2 and N2O from air trapped in ice cores

    Directory of Open Access Journals (Sweden)

    H. Fischer

    2011-07-01

    Full Text Available In order to provide high precision stable carbon isotope ratios (δ13CO2 or δ13C of CO2 from small bubbly, partially and fully clathrated ice core samples we developed a new method based on sublimation coupled to gas chromatography-isotope ratio mass spectrometry (GC-IRMS. In a first step the trapped air is quantitatively released from ~30 g of ice and CO2 together with N2O are separated from the bulk air components and stored in a miniature glass tube. In an off-line step, the extracted sample is introduced into a helium carrier flow using a minimised tube cracker device. Prior to measurement, N2O and organic sample contaminants are gas chromatographically separated from CO2. Pulses of a CO2/N2O mixture are admitted to the tube cracker and follow the path of the sample through the system. This allows an identical treatment and comparison of sample and standard peaks. The ability of the method to reproduce δ13C from bubble and clathrate ice is verified on different ice cores. We achieve reproducibilities for bubble ice between 0.05 ‰ and 0.07 ‰ and for clathrate ice between 0.05 ‰ and 0.09 ‰ (dependent on the ice core used. A comparison of our data with measurements on bubble ice from the same ice core but using a mechanical extraction device shows no significant systematic offset. In addition to δ13C, the CO2 and N2O mixing ratios can be volumetrically derived with a precision of 2 ppmv and 8 ppbv, respectively.

  9. Investigations and researches on CO2 balance in a high-temperature carbon dioxide separation technology; Nisanka tanso koon bunri gijutsu ni okeru CO2 balance ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    With an objective to select a promising process by comparing application environments and effectiveness of a high-temperature carbon dioxide separation, recovery and re-utilization technology with other methods, investigations were performed on reducible amount of carbon dioxide discharge by using material balance and system introduction. A large number of chemical and physical technologies are being developed for the separation and refining methods. This paper discusses the technologies for their application to iron and steel making, oil refining, and petrochemical industries, the so-called heavy and large product industries. As a possibility of utilizing the high-temperature separated CO2 in iron and steel making, an investigation was given on the direct iron ore smelting reduction process. It would be unreasonable to use CO2 in oil refining as a substitute to air to regenerate a catalytic decomposition and reformation catalyst because of decline in the catalytic activity. A discussion was given on a case to replace steam with CO2 in steam reformation and pyrolysis of hydrocarbons. The discussion requires the objective to be focused on such items as C/H ratio at a reformer outlet and relationship of balance in decomposition products. The C1 chemical and others were reviewed to search possibilities for their use as raw materials of chemicals used in chemical industries. Possibilities were discussed to fix high-temperature CO2 into peridotite and serpentine. 42 refs., 32 figs., 11 tabs.

  10. Modeling CO2 Storage in Fractured Reservoirs: Fracture-Matrix Interactions of Free-Phase and Dissolved CO2